1.
ChemSpider
–
ChemSpider is a database of chemicals. ChemSpider is owned by the Royal Society of Chemistry, the database contains information on more than 50 million molecules from over 500 data sources including, Each chemical is given a unique identifier, which forms part of a corresponding URL. This is an approach to develop an online chemistry database. The search can be used to widen or restrict already found results, structure searching on mobile devices can be done using free apps for iOS and for the Android. The ChemSpider database has been used in combination with text mining as the basis of document markup. The result is a system between chemistry documents and information look-up via ChemSpider into over 150 data sources. ChemSpider was acquired by the Royal Society of Chemistry in May,2009, prior to the acquisition by RSC, ChemSpider was controlled by a private corporation, ChemZoo Inc. The system was first launched in March 2007 in a release form. ChemSpider has expanded the generic support of a database to include support of the Wikipedia chemical structure collection via their WiChempedia implementation. A number of services are available online. SyntheticPages is an interactive database of synthetic chemistry procedures operated by the Royal Society of Chemistry. Users submit synthetic procedures which they have conducted themselves for publication on the site and these procedures may be original works, but they are more often based on literature reactions. Citations to the published procedure are made where appropriate. They are checked by an editor before posting. The pages do not undergo formal peer-review like a journal article. The comments are moderated by scientific editors. The intention is to collect practical experience of how to conduct useful chemical synthesis in the lab, while experimental methods published in an ordinary academic journal are listed formally and concisely, the procedures in ChemSpider SyntheticPages are given with more practical detail. Comments by submitters are included as well, other publications with comparable amounts of detail include Organic Syntheses and Inorganic Syntheses
ChemSpider
–
ChemSpider
2.
E number
–
E numbers are codes for substances that are permitted to be used as food additives for use within the European Union and Switzerland. Commonly found on labels, their safety assessment and approval are the responsibility of the European Food Safety Authority. Having a single unified list for food additives was first agreed upon in 1962 with food colouring, in 1964, the directives for preservatives were added,1970 for antioxidants and 1974 for the emulsifiers, stabilisers, thickeners and gelling agents. They are increasingly, though rarely, found on North American packaging. In some European countries, E number is used informally as a pejorative term for artificial food additives. This is incorrect, because many components of foods have E numbers, e. g. vitamin C. NB, Not all examples of a fall into the given numeric range. Moreover, many chemicals, particularly in the E400–499 range, have a variety of purposes, the list shows all components that have or had an E-number assigned. Not all additives listed are still allowed in the EU, but are listed as they used to have an E-number, for an overview of currently allowed additives see here. Includes Lists of authorised food additives Food additives database
E number
–
A solution of E101
riboflavin (also known as vitamin B2)
E number
–
Crystals of E621
Monosodium glutamate, a flavour enhancer
3.
PubChem
–
PubChem is a database of chemical molecules and their activities against biological assays. The system is maintained by the National Center for Biotechnology Information, a component of the National Library of Medicine, PubChem can be accessed for free through a web user interface. Millions of compound structures and descriptive datasets can be downloaded via FTP. PubChem contains substance descriptions and small molecules with fewer than 1000 atoms and 1000 bonds, more than 80 database vendors contribute to the growing PubChem database. PubChem consists of three dynamically growing primary databases, as of 28 January 2016, Compounds,82.6 million entries, contains pure and characterized chemical compounds. Substances,198 million entries, contains also mixtures, extracts, complexes, bioAssay, bioactivity results from 1.1 million high-throughput screening programs with several million values. PubChem contains its own online molecule editor with SMILES/SMARTS and InChI support that allows the import and export of all common chemical file formats to search for structures and fragments. In the text search form the database fields can be searched by adding the name in square brackets to the search term. A numeric range is represented by two separated by a colon. The search terms and field names are case-insensitive, parentheses and the logical operators AND, OR, and NOT can be used. AND is assumed if no operator is used, example,0,5000,50,10 -5,5 PubChem was released in 2004. The American Chemical Society has raised concerns about the publicly supported PubChem database and they have a strong interest in the issue since the Chemical Abstracts Service generates a large percentage of the societys revenue. To advocate their position against the PubChem database, ACS has actively lobbied the US Congress, soon after PubChems creation, the American Chemical Society lobbied U. S. Congress to restrict the operation of PubChem, which they asserted competes with their Chemical Abstracts Service
PubChem
–
PubChem
4.
Chemical formula
–
These are limited to a single typographic line of symbols, which may include subscripts and superscripts. A chemical formula is not a name, and it contains no words. Although a chemical formula may imply certain simple chemical structures, it is not the same as a full chemical structural formula. Chemical formulas can fully specify the structure of only the simplest of molecules and chemical substances, the simplest types of chemical formulas are called empirical formulas, which use letters and numbers indicating the numerical proportions of atoms of each type. Molecular formulas indicate the numbers of each type of atom in a molecule. For example, the formula for glucose is CH2O, while its molecular formula is C6H12O6. This is possible if the relevant bonding is easy to show in one dimension, an example is the condensed molecular/chemical formula for ethanol, which is CH3-CH2-OH or CH3CH2OH. For reasons of structural complexity, there is no condensed chemical formula that specifies glucose, chemical formulas may be used in chemical equations to describe chemical reactions and other chemical transformations, such as the dissolving of ionic compounds into solution. A chemical formula identifies each constituent element by its chemical symbol, in empirical formulas, these proportions begin with a key element and then assign numbers of atoms of the other elements in the compound, as ratios to the key element. For molecular compounds, these numbers can all be expressed as whole numbers. For example, the formula of ethanol may be written C2H6O because the molecules of ethanol all contain two carbon atoms, six hydrogen atoms, and one oxygen atom. Some types of compounds, however, cannot be written with entirely whole-number empirical formulas. An example is boron carbide, whose formula of CBn is a variable non-whole number ratio with n ranging from over 4 to more than 6.5. When the chemical compound of the consists of simple molecules. These types of formulas are known as molecular formulas and condensed formulas. A molecular formula enumerates the number of atoms to reflect those in the molecule, so that the formula for glucose is C6H12O6 rather than the glucose empirical formula. However, except for very simple substances, molecular chemical formulas lack needed structural information, for simple molecules, a condensed formula is a type of chemical formula that may fully imply a correct structural formula. For example, ethanol may be represented by the chemical formula CH3CH2OH
Chemical formula
–
Al 2 (SO 4) 3
5.
Density
–
The density, or more precisely, the volumetric mass density, of a substance is its mass per unit volume. The symbol most often used for density is ρ, although the Latin letter D can also be used. Mathematically, density is defined as mass divided by volume, ρ = m V, where ρ is the density, m is the mass, and V is the volume. In some cases, density is defined as its weight per unit volume. For a pure substance the density has the numerical value as its mass concentration. Different materials usually have different densities, and density may be relevant to buoyancy, purity, osmium and iridium are the densest known elements at standard conditions for temperature and pressure but certain chemical compounds may be denser. Thus a relative density less than one means that the floats in water. The density of a material varies with temperature and pressure and this variation is typically small for solids and liquids but much greater for gases. Increasing the pressure on an object decreases the volume of the object, increasing the temperature of a substance decreases its density by increasing its volume. In most materials, heating the bottom of a results in convection of the heat from the bottom to the top. This causes it to rise relative to more dense unheated material, the reciprocal of the density of a substance is occasionally called its specific volume, a term sometimes used in thermodynamics. Density is a property in that increasing the amount of a substance does not increase its density. Archimedes knew that the irregularly shaped wreath could be crushed into a cube whose volume could be calculated easily and compared with the mass, upon this discovery, he leapt from his bath and ran naked through the streets shouting, Eureka. As a result, the term eureka entered common parlance and is used today to indicate a moment of enlightenment, the story first appeared in written form in Vitruvius books of architecture, two centuries after it supposedly took place. Some scholars have doubted the accuracy of this tale, saying among other things that the method would have required precise measurements that would have been difficult to make at the time, from the equation for density, mass density has units of mass divided by volume. As there are units of mass and volume covering many different magnitudes there are a large number of units for mass density in use. The SI unit of kilogram per metre and the cgs unit of gram per cubic centimetre are probably the most commonly used units for density.1,000 kg/m3 equals 1 g/cm3. In industry, other larger or smaller units of mass and or volume are often more practical, see below for a list of some of the most common units of density
Density
–
Air density vs. temperature
6.
Melting point
–
The melting point of a solid is the temperature at which it changes state from solid to liquid at atmospheric pressure. At the melting point the solid and liquid phase exist in equilibrium, the melting point of a substance depends on pressure and is usually specified at standard pressure. When considered as the temperature of the change from liquid to solid. Because of the ability of some substances to supercool, the point is not considered as a characteristic property of a substance. For most substances, melting and freezing points are approximately equal, for example, the melting point and freezing point of mercury is 234.32 kelvins. However, certain substances possess differing solid-liquid transition temperatures, for example, agar melts at 85 °C and solidifies from 31 °C to 40 °C, such direction dependence is known as hysteresis. The melting point of ice at 1 atmosphere of pressure is close to 0 °C. In the presence of nucleating substances the freezing point of water is the same as the melting point, the chemical element with the highest melting point is tungsten, at 3687 K, this property makes tungsten excellent for use as filaments in light bulbs. Many laboratory techniques exist for the determination of melting points, a Kofler bench is a metal strip with a temperature gradient. Any substance can be placed on a section of the strip revealing its thermal behaviour at the temperature at that point, differential scanning calorimetry gives information on melting point together with its enthalpy of fusion. A basic melting point apparatus for the analysis of crystalline solids consists of an oil bath with a transparent window, the several grains of a solid are placed in a thin glass tube and partially immersed in the oil bath. The oil bath is heated and with the aid of the melting of the individual crystals at a certain temperature can be observed. In large/small devices, the sample is placed in a heating block, the measurement can also be made continuously with an operating process. For instance, oil refineries measure the point of diesel fuel online, meaning that the sample is taken from the process. This allows for more frequent measurements as the sample does not have to be manually collected, for refractory materials the extremely high melting point may be determined by heating the material in a black body furnace and measuring the black-body temperature with an optical pyrometer. For the highest melting materials, this may require extrapolation by several hundred degrees, the spectral radiance from an incandescent body is known to be a function of its temperature. An optical pyrometer matches the radiance of a body under study to the radiance of a source that has been previously calibrated as a function of temperature, in this way, the measurement of the absolute magnitude of the intensity of radiation is unnecessary. However, known temperatures must be used to determine the calibration of the pyrometer, for temperatures above the calibration range of the source, an extrapolation technique must be employed
Melting point
–
Melting points (in blue) and boiling points (in pink) of the first eight
carboxylic acids (°C)
Melting point
–
Kofler bench with samples for calibration
Melting point
–
Automatic digital melting point meter
Melting point
–
Pressure dependence of water melting point
7.
Aqueous solution
–
An aqueous solution is a solution in which the solvent is water. It is usually shown in chemical equations by appending to the relevant chemical formula, for example, a solution of table salt, or sodium chloride, in water would be represented as Na+ + Cl−. The word aqueous means pertaining to, related to, similar to, as water is an excellent solvent and is also naturally abundant, it is a ubiquitous solvent in chemistry. Substances that are hydrophobic often do not dissolve well in water, an example of a hydrophilic substance is sodium chloride. Acids and bases are aqueous solutions, as part of their Arrhenius definitions, the ability of a substance to dissolve in water is determined by whether the substance can match or exceed the strong attractive forces that water molecules generate between themselves. If the substance lacks the ability to dissolve in water the molecules form a precipitate, reactions in aqueous solutions are usually metathesis reactions. Metathesis reactions are another term for double-displacement, that is, when a cation displaces to form a bond with the other anion. The cation bonded with the latter anion will dissociate and bond with the other anion, aqueous solutions that conduct electric current efficiently contain strong electrolytes, while ones that conduct poorly are considered to have weak electrolytes. Those strong electrolytes are substances that are ionized in water. Nonelectrolytes are substances that dissolve in water yet maintain their molecular integrity, examples include sugar, urea, glycerol, and methylsulfonylmethane. When writing the equations of reactions, it is essential to determine the precipitate. To determine the precipitate, one must consult a chart of solubility, soluble compounds are aqueous, while insoluble compounds are the precipitate. Remember that there may not always be a precipitate, when performing calculations regarding the reacting of one or more aqueous solutions, in general one must know the concentration, or molarity, of the aqueous solutions. Solution concentration is given in terms of the form of the prior to it dissolving. Metal ions in aqueous solution Solubility Dissociation Acid-base reaction theories Properties of water Zumdahl S.1997, 4th ed. Boston, Houghton Mifflin Company
Aqueous solution
–
The first
solvation shell of a sodium ion dissolved in water.
8.
Standard enthalpy change of formation
–
Its symbol is ΔHo f or ΔfHo. The superscript Plimsoll on this symbol indicates that the process has occurred under standard conditions at the specified temperature. One exception is phosphorus, for which the most stable form at 1 atm is black phosphorus and this is true for all enthalpies of formation. In physics the energy per particle is expressed in electronvolts. All elements in their states have a standard enthalpy of formation of zero. The formation reaction is a constant pressure and constant temperature process, since the pressure of the standard formation reaction is fixed at 1 atm, the standard formation enthalpy or reaction heat is a function of temperature. For tabulation purposes, standard formation enthalpies are all given at a temperature,298 K. The standard enthalpy of formation is equivalent to the sum of separate processes included in the Born–Haber cycle of synthesis reactions. This is because enthalpy is a state function, in the example above the standard enthalpy change of formation for sodium chloride is equal to the sum of the standard enthalpy change of formation for each of the steps involved in the process. This is especially useful for very long reactions with many intermediate steps, chemists may use standard enthalpies of formation for a reaction that is hypothetical. That it is shows that the reaction, if it were to proceed, would be exothermic. It is possible to heat of formations for simple unstrained organic compounds with the Heat of formation group additivity method. Standard enthalpies of formation are used in thermochemistry to find the enthalpy change of any reaction. This implies that the reaction is exothermic, the converse is also true, the standard enthalpy of reaction will be positive for an endothermic reaction. When a reaction is reversed, the magnitude of ΔH stays the same, when the balanced equation for a reaction is multiplied by an integer, the corresponding value of ΔH must be multiplied by that integer as well. Allotropes of an element other than the state generally have non-zero standard enthalpies of formation. Standard enthalpy of sublimation, or heat of sublimation, is defined as the required to sublime one mole of the substance under standard conditions. Standard enthalpy of solution is the change associated with the dissolution of a substance in a solvent at constant pressure under standard conditions
Standard enthalpy change of formation
–
Standard enthalpy change of formation in
Born-Haber diagram for
lithium fluoride.
9.
IDLH
–
Examples include smoke or other poisonous gases at sufficiently high concentrations. It is calculated using the LD50 or LC50, IDLH values are often used to guide the selection of breathing apparatus that are made available to workers or firefighters in specific situations. The NIOSH definition does not include oxygen deficiency although atmosphere-supplying breathing apparatus is also required, examples include high altitudes and unventilated, confined spaces. It also uses the broader term impair, rather than prevent, for example, blinding but non-toxic smoke could be considered IDLH under the OSHA definition if it would impair the ability to escape a dangerous but not life-threatening atmosphere. The OSHA definition is part of a standard, which is the minimum legal requirement. If the concentration of substances is IDLH, the worker must use the most reliable respirators. Such respirators should not use cartridges or canister with the sorbent, in addition, the respirator must maintain positive pressure under the mask during inspiration, as this will prevent the leakage of unfiltered air through the gaps. The following examples are listed in reference to IDLH values, NIOSH IDLH site 1910.134 Respiratory protection definitions
IDLH
–
Pressure-demand supplied-air respirator equipped with a full facepiece in combination with an auxiliary pressure-demand self-contained breathing apparatus - for IDLH conditions in workplace.
IDLH
–
Pressure-demand self-contained breathing apparatus with a full facepiece - for IDLH conditions in workplace.
10.
Starch
–
Starch or amylum is a polymeric carbohydrate consisting of a large number of glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants as an energy store and it is the most common carbohydrate in human diets and is contained in large amounts in staple foods such as potatoes, wheat, maize, rice, and cassava. Pure starch is a white, tasteless and odorless powder that is insoluble in water or alcohol. It consists of two types of molecules, the linear and helical amylose and the branched amylopectin, depending on the plant, starch generally contains 20 to 25% amylose and 75 to 80% amylopectin by weight. Glycogen, the store of animals, is a more branched version of amylopectin. In industry, starch is converted into sugars, for example by malting and it is processed to produce many of the sugars used in processed foods. Dissolving starch in water gives wheatpaste, which can be used as a thickening, stiffening or gluing agent. The biggest industrial non-food use of starch is as an adhesive in the papermaking process, starch can be applied to parts of some garments before ironing, to stiffen them. The word starch is from a Germanic root with the strong, stiff. Amylum for starch is from the Greek αμυλον, amylon which means not ground at a mill, the root amyl is used in biochemistry for several compounds related to starch. Starch grains from the rhizomes of Typha as flour have been identified from grinding stones in Europe dating back to 30,000 years ago, starch grains from sorghum were found on grind stones in caves in Ngalue, Mozambique dating up to 100,000 years ago. Pure extracted wheat starch paste was used in Ancient Egypt possibly to glue papyrus, the extraction of starch is first described in the Natural History of Pliny the Elder around AD 77–79. Romans used it also in cosmetic creams, to powder the hair, persians and Indians used it to make dishes similar to gothumai wheat halva. Rice starch as surface treatment of paper has been used in production in China. In addition to starchy plants consumed directly,66 million tonnes of starch were being produced per year world-wide by 2008. In the EU this was around 8.5 million tonnes, with around 40% being used for applications and 60% for food uses. Most green plants use starch as their energy store, an exception is the family Asteraceae, where starch is replaced by the fructan inulin. In photosynthesis, plants use light energy to produce glucose from carbon dioxide, the glucose is used to make cellulose fibers, the structural component of the plant, or is stored in the form of starch granules, in amyloplasts
Starch
–
Starch
Starch
–
Starch, 800x magnified, under polarized light, showing characteristic
extinction cross
Starch
–
Rice starch seen on light microscope. Characteristic for the rice starch is that starch granules have an angular outline and some of them are attached to each other and form larger granules
Starch
–
Granules of wheat starch, stained with iodine, photographed through a light microscope
11.
Organic compound
–
An organic compound is virtually any chemical compound that contains carbon, although a consensus definition remains elusive and likely arbitrary. Organic compounds are rare terrestrially, but of importance because all known life is based on organic compounds. The most basic petrochemicals are considered the building blocks of organic chemistry, for historical reasons discussed below, a few types of carbon-containing compounds, such as carbides, carbonates, simple oxides of carbon, and cyanides are considered inorganic. The distinction between organic and inorganic compounds, while useful in organizing the vast subject of chemistry. Organic chemistry is the science concerned with all aspects of organic compounds, Organic synthesis is the methodology of their preparation. The word organic is historical, dating to the 1st century, for many centuries, Western alchemists believed in vitalism. This is the theory that certain compounds could be synthesized only from their classical elements—earth, water, air, vitalism taught that these organic compounds were fundamentally different from the inorganic compounds that could be obtained from the elements by chemical manipulation. Vitalism survived for a while even after the rise of modern atomic theory and it first came under question in 1824, when Friedrich Wöhler synthesized oxalic acid, a compound known to occur only in living organisms, from cyanogen. A more decisive experiment was Wöhlers 1828 synthesis of urea from the inorganic salts potassium cyanate, urea had long been considered an organic compound, as it was known to occur only in the urine of living organisms. Wöhlers experiments were followed by others, in which increasingly complex organic substances were produced from inorganic ones without the involvement of any living organism. Even though vitalism has been discredited, scientific nomenclature retains the distinction between organic and inorganic compounds, still, even the broadest definition requires excluding alloys that contain carbon, including steel. The C-H definition excludes compounds that are considered organic, neither urea nor oxalic acid is organic by this definition, yet they were two key compounds in the vitalism debate. The IUPAC Blue Book on organic nomenclature specifically mentions urea and oxalic acid, other compounds lacking C-H bonds but traditionally considered organic include benzenehexol, mesoxalic acid, and carbon tetrachloride. Mellitic acid, which contains no C-H bonds, is considered an organic substance in Martian soil. The C-H bond-only rule also leads to somewhat arbitrary divisions in sets of carbon-fluorine compounds, for example, CF4 would be considered by this rule to be inorganic, whereas CF3H would be organic. Organic compounds may be classified in a variety of ways, one major distinction is between natural and synthetic compounds. Another distinction, based on the size of organic compounds, distinguishes between small molecules and polymers, natural compounds refer to those that are produced by plants or animals. Many of these are extracted from natural sources because they would be more expensive to produce artificially
Organic compound
–
Methane is one of the simplest organic compounds
12.
Carbon
–
Carbon is a chemical element with symbol C and atomic number 6. It is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds, three isotopes occur naturally, 12C and 13C being stable, while 14C is a radioactive isotope, decaying with a half-life of about 5,730 years. Carbon is one of the few elements known since antiquity, Carbon is the 15th most abundant element in the Earths crust, and the fourth most abundant element in the universe by mass after hydrogen, helium, and oxygen. It is the second most abundant element in the body by mass after oxygen. The atoms of carbon can bond together in different ways, termed allotropes of carbon, the best known are graphite, diamond, and amorphous carbon. The physical properties of carbon vary widely with the allotropic form, for example, graphite is opaque and black while diamond is highly transparent. Graphite is soft enough to form a streak on paper, while diamond is the hardest naturally occurring material known, graphite is a good electrical conductor while diamond has a low electrical conductivity. Under normal conditions, diamond, carbon nanotubes, and graphene have the highest thermal conductivities of all known materials, all carbon allotropes are solids under normal conditions, with graphite being the most thermodynamically stable form. They are chemically resistant and require high temperature to react even with oxygen, the most common oxidation state of carbon in inorganic compounds is +4, while +2 is found in carbon monoxide and transition metal carbonyl complexes. The largest sources of carbon are limestones, dolomites and carbon dioxide, but significant quantities occur in organic deposits of coal, peat, oil. For this reason, carbon has often referred to as the king of the elements. The allotropes of carbon graphite, one of the softest known substances, and diamond. It bonds readily with other small atoms including other carbon atoms, Carbon is known to form almost ten million different compounds, a large majority of all chemical compounds. Carbon also has the highest sublimation point of all elements, although thermodynamically prone to oxidation, carbon resists oxidation more effectively than elements such as iron and copper that are weaker reducing agents at room temperature. Carbon is the element, with a ground-state electron configuration of 1s22s22p2. Its first four ionisation energies,1086.5,2352.6,4620.5 and 6222.7 kJ/mol, are higher than those of the heavier group 14 elements. Carbons covalent radii are normally taken as 77.2 pm,66.7 pm and 60.3 pm, although these may vary depending on coordination number, in general, covalent radius decreases with lower coordination number and higher bond order. Carbon compounds form the basis of all life on Earth
Carbon
–
Graphite (left) and diamond (right), the two most well-known allotropes of carbon
Carbon
–
Spectral lines of carbon
Carbon
–
A large sample of glassy carbon.
Carbon
–
Graphite ore
13.
Hydrogen
–
Hydrogen is a chemical element with chemical symbol H and atomic number 1. With a standard weight of circa 1.008, hydrogen is the lightest element on the periodic table. Its monatomic form is the most abundant chemical substance in the Universe, non-remnant stars are mainly composed of hydrogen in the plasma state. The most common isotope of hydrogen, termed protium, has one proton, the universal emergence of atomic hydrogen first occurred during the recombination epoch. At standard temperature and pressure, hydrogen is a colorless, odorless, tasteless, non-toxic, nonmetallic, since hydrogen readily forms covalent compounds with most nonmetallic elements, most of the hydrogen on Earth exists in molecular forms such as water or organic compounds. Hydrogen plays an important role in acid–base reactions because most acid-base reactions involve the exchange of protons between soluble molecules. In ionic compounds, hydrogen can take the form of a charge when it is known as a hydride. The hydrogen cation is written as though composed of a bare proton, Hydrogen gas was first artificially produced in the early 16th century by the reaction of acids on metals. Industrial production is mainly from steam reforming natural gas, and less often from more energy-intensive methods such as the electrolysis of water. Most hydrogen is used near the site of its production, the two largest uses being fossil fuel processing and ammonia production, mostly for the fertilizer market, Hydrogen is a concern in metallurgy as it can embrittle many metals, complicating the design of pipelines and storage tanks. Hydrogen gas is flammable and will burn in air at a very wide range of concentrations between 4% and 75% by volume. The enthalpy of combustion is −286 kJ/mol,2 H2 + O2 →2 H2O +572 kJ Hydrogen gas forms explosive mixtures with air in concentrations from 4–74%, the explosive reactions may be triggered by spark, heat, or sunlight. The hydrogen autoignition temperature, the temperature of spontaneous ignition in air, is 500 °C, the detection of a burning hydrogen leak may require a flame detector, such leaks can be very dangerous. Hydrogen flames in other conditions are blue, resembling blue natural gas flames, the destruction of the Hindenburg airship was a notorious example of hydrogen combustion and the cause is still debated. The visible orange flames in that incident were the result of a mixture of hydrogen to oxygen combined with carbon compounds from the airship skin. H2 reacts with every oxidizing element, the ground state energy level of the electron in a hydrogen atom is −13.6 eV, which is equivalent to an ultraviolet photon of roughly 91 nm wavelength. The energy levels of hydrogen can be calculated fairly accurately using the Bohr model of the atom, however, the atomic electron and proton are held together by electromagnetic force, while planets and celestial objects are held by gravity. The most complicated treatments allow for the effects of special relativity
Hydrogen
–
Purple glow in its plasma state
Hydrogen
–
The
Space Shuttle Main Engine burnt hydrogen with oxygen, producing a nearly invisible flame at full thrust.
Hydrogen
–
Spectral lines of hydrogen
Hydrogen
–
First tracks observed in
liquid hydrogen bubble chamber at the
Bevatron
14.
Oxygen
–
Oxygen is a chemical element with symbol O and atomic number 8. It is a member of the group on the periodic table and is a highly reactive nonmetal. By mass, oxygen is the third-most abundant element in the universe, after hydrogen, at standard temperature and pressure, two atoms of the element bind to form dioxygen, a colorless and odorless diatomic gas with the formula O2. This is an important part of the atmosphere and diatomic oxygen gas constitutes 20. 8% of the Earths atmosphere, additionally, as oxides the element makes up almost half of the Earths crust. Most of the mass of living organisms is oxygen as a component of water, conversely, oxygen is continuously replenished by photosynthesis, which uses the energy of sunlight to produce oxygen from water and carbon dioxide. Oxygen is too reactive to remain a free element in air without being continuously replenished by the photosynthetic action of living organisms. Another form of oxygen, ozone, strongly absorbs ultraviolet UVB radiation, but ozone is a pollutant near the surface where it is a by-product of smog. At low earth orbit altitudes, sufficient atomic oxygen is present to cause corrosion of spacecraft, the name oxygen was coined in 1777 by Antoine Lavoisier, whose experiments with oxygen helped to discredit the then-popular phlogiston theory of combustion and corrosion. One of the first known experiments on the relationship between combustion and air was conducted by the 2nd century BCE Greek writer on mechanics, Philo of Byzantium. In his work Pneumatica, Philo observed that inverting a vessel over a burning candle, Philo incorrectly surmised that parts of the air in the vessel were converted into the classical element fire and thus were able to escape through pores in the glass. Many centuries later Leonardo da Vinci built on Philos work by observing that a portion of air is consumed during combustion and respiration, Oxygen was discovered by the Polish alchemist Sendivogius, who considered it the philosophers stone. In the late 17th century, Robert Boyle proved that air is necessary for combustion, English chemist John Mayow refined this work by showing that fire requires only a part of air that he called spiritus nitroaereus. From this he surmised that nitroaereus is consumed in both respiration and combustion, Mayow observed that antimony increased in weight when heated, and inferred that the nitroaereus must have combined with it. Accounts of these and other experiments and ideas were published in 1668 in his work Tractatus duo in the tract De respiratione. Robert Hooke, Ole Borch, Mikhail Lomonosov, and Pierre Bayen all produced oxygen in experiments in the 17th and the 18th century but none of them recognized it as a chemical element. This may have been in part due to the prevalence of the philosophy of combustion and corrosion called the phlogiston theory, which was then the favored explanation of those processes. Established in 1667 by the German alchemist J. J. Becher, one part, called phlogiston, was given off when the substance containing it was burned, while the dephlogisticated part was thought to be its true form, or calx. The fact that a substance like wood gains overall weight in burning was hidden by the buoyancy of the combustion products
Oxygen
–
Spectral lines of oxygen
Oxygen
Oxygen
–
A trickle of liquid oxygen is deflected by a magnetic field, illustrating its paramagnetic property
Oxygen
–
Oxygen discharge (spectrum) tube. The green color is similar to the color of an
"aurora borealis"
15.
Polysaccharide
–
They range in structure from linear to highly branched. Examples include storage polysaccharides such as starch and glycogen, and structural polysaccharides such as cellulose, polysaccharides are often quite heterogeneous, containing slight modifications of the repeating unit. Depending on the structure, these macromolecules can have distinct properties from their building blocks. They may be amorphous or even insoluble in water, natural saccharides are generally of simple carbohydrates called monosaccharides with general formula n where n is three or more. Examples of monosaccharides are glucose, fructose, and glyceraldehyde, polysaccharides, meanwhile, have a general formula of Cxy where x is usually a large number between 200 and 2500. When the repeating units in the backbone are six-carbon monosaccharides, as is often the case, the general formula simplifies to n. Polysaccharides are an important class of biological polymers and their function in living organisms is usually either structure- or storage-related. Starch is used as a polysaccharide in plants, being found in the form of both amylose and the branched amylopectin. In animals, the structurally similar glucose polymer is the more densely branched glycogen, glycogens properties allow it to be metabolized more quickly, which suits the active lives of moving animals. Cellulose and chitin are examples of structural polysaccharides, cellulose is used in the cell walls of plants and other organisms, and is said to be the most abundant organic molecule on Earth. It has many such as a significant role in the paper and textile industries, and is used as a feedstock for the production of rayon, cellulose acetate, celluloid. Chitin has a structure, but has nitrogen-containing side branches. It is found in arthropod exoskeletons and in the walls of some fungi. It also has multiple uses, including surgical threads, polysaccharides also include callose or laminarin, chrysolaminarin, xylan, arabinoxylan, mannan, fucoidan and galactomannan. Nutrition polysaccharides are common sources of energy, many organisms can easily break down starches into glucose, however, most organisms cannot metabolize cellulose or other polysaccharides like chitin and arabinoxylans. These carbohydrate types can be metabolized by bacteria and protists. Ruminants and termites, for example, use microorganisms to process cellulose, even though these complex carbohydrates are not very digestible, they provide important dietary elements for humans. Called dietary fiber, these carbohydrates enhance digestion among other benefits, the main action of dietary fiber is to change the nature of the contents of the gastrointestinal tract, and to change how other nutrients and chemicals are absorbed
Polysaccharide
–
A view of the
atomic structure of a single branched strand of
glucose units in a glycogen
molecule.
Polysaccharide
–
Amylose is a linear
polymer of
glucose mainly linked with α(1→4) bonds. It can be made of several thousands of glucose units. It is one of the two components of
starch, the other being
amylopectin.
16.
Glycosidic bond
–
In chemistry, a glycosidic bond or glycosidic linkage is a type of covalent bond that joins a carbohydrate molecule to another group, which may or may not be another carbohydrate. A glycosidic bond is formed between the hemiacetal or hemiketal group of a saccharide and the group of some compound such as an alcohol. A substance containing a glycosidic bond is a glycoside, glycosidic bonds of the form discussed above are known as O-glycosidic bonds, in reference to the glycosidic oxygen that links the glycoside to the aglycone or reducing end sugar. In analogy, one also considers S-glycosidic bonds, where the oxygen of the bond is replaced with a sulfur atom. In the same way, N-glycosidic bonds, have the glycosidic oxygen replaced with nitrogen. Substances containing N-glycosidic bonds are known as glycosylamines. C-glycosyl bonds have the oxygen replaced by a carbon, the term C-glycoside is considered a misnomer by IUPAC and is discouraged. All of these modified glycosidic bonds have different susceptibility to hydrolysis, one distinguishes between α- and β-glycosidic bonds based on the relative stereochemistry of the anomeric position and the stereocenter furthest from C1 in the saccharide. An α-glycosidic bond is formed when both carbons have the same stereochemistry, whereas a β-glycosidic bond occurs when the two carbons have different stereochemistry. One complicating issue is that the alpha and beta conformations were originally defined based on the orientation of the major constituents in a Haworth projection. In this case, for D-sugars, a beta conformation would see the major constituent at each carbon drawn above the plane of the ring, for L-sugars, the definitions would then, necessarily, reverse. This is worth noting as these older definitions still permeate the literature, pharmacologists often join substances to glucuronic acid via glycosidic bonds in order to increase their water solubility, this is known as glucuronidation. Many other glycosides have important physiological functions, Nüchter et al. have shown a new approach to Fischer Glycosylation. Employing a microwave oven equipped with refluxing apparatus in a reactor with pressure bombs, Nüchter et al. were able to achieve 100% yield of α-. This method can be performed on a multi-kilogram scale, ondruschka, and W. Lautenschläger, Synthetic Communications 31,1277. Vishal Y Joshis method Joshi et al, d-glucose is first protected by forming the peracetate by addition of acetic anhydride in acetic acid, and then addition of hydrogen bromide which brominates at the 5-position. On addition of the alcohol ROH and lithium carbonate, the OR replaces the bromine and it was suggested by Joshi et al. that lithium acts as the nucleophile that attacks the carbon at the 5-position and through a transition state the alcohol is substituted for the bromine group. Glycoside hydrolases, are enzymes that break glycosidic bonds, glycoside hydrolases typically can act either on α- or on β-glycosidic bonds, but not on both
Glycosidic bond
–
A β-1,6
glucan molecule showing how carbons are numbered. The terminal saccharide is linked via a β-1,6 glycosidic bond. The remaining linkages are all β-1,3.
Glycosidic bond
–
Adenosine, a component of
RNA, results from the sugar
ribose and
adenine via the formation of an N-glycosidic bond (shown as the vertical line between the N and the sugar cycle)
17.
Cell wall
–
A cell wall is a structural layer surrounding some types of cells, situated outside the cell membrane. It can be tough, flexible, and sometimes rigid and it provides the cell with both structural support and protection, and also acts as a filtering mechanism. Cell walls are present in most prokaryotes, in algae, plants and fungi, a major function is to act as pressure vessels, preventing over-expansion of the cell when water enters. The composition of cell walls varies between species and may depend on type and developmental stage. The primary cell wall of plants is composed of the polysaccharides cellulose, hemicellulose. Often, other such as lignin, suberin or cutin are anchored to or embedded in plant cell walls. Algae possess walls made of glycoproteins and polysaccharides such as carrageenan, in bacteria, the cell wall is composed of peptidoglycan. The cell walls of archaea have various compositions, and may be formed of glycoprotein S-layers, pseudopeptidoglycan, Fungi possess cell walls made of the glucosamine polymer chitin. Unusually, diatoms have a wall composed of biogenic silica. A plant cell wall was first observed and named by Robert Hooke in 1665, in 1804, Karl Rudolphi and J. H. F. Link proved that cells had independent cell walls, before, it had been thought that cells shared walls and that fluid passed between them this way. The mode of formation of the wall was controversial in the 19th century. Hugo von Mohl advocated the idea that the wall grows by apposition. Carl Nägeli believed that the growth of the wall in thickness, each theory was improved in the following decades, the apposition theory by Eduard Strasburger, and the intussusception theory by Julius Wiesner. In 1930, Ernst Münch coined the term apoplast in order to separate the living symplast from the dead plant region, Cell walls serve similar purposes in those organisms that possess them. They may give cells rigidity and strength, offering protection against mechanical stress, in multicellular organisms, they permit the organism to build and hold a definite shape. Cell walls also limit the entry of large molecules that may be toxic to the cell and they further permit the creation of stable osmotic environments by preventing osmotic lysis and helping to retain water. Their composition, properties, and form may change during the cell cycle, in most cells, the cell wall is flexible, meaning that it will bend rather than holding a fixed shape, but has considerable tensile strength
Cell wall
–
Diagram of the plant cell, with the cell wall in green.
18.
Green plants
–
Plants are mainly multicellular, predominantly photosynthetic eukaryotes of the kingdom Plantae. The term is generally limited to the green plants, which form an unranked clade Viridiplantae. This includes the plants, conifers and other gymnosperms, ferns, clubmosses, hornworts, liverworts, mosses and the green algae. Green plants have cell walls containing cellulose and obtain most of their energy from sunlight via photosynthesis by primary chloroplasts and their chloroplasts contain chlorophylls a and b, which gives them their green color. Some plants are parasitic and have lost the ability to produce amounts of chlorophyll or to photosynthesize. Plants are characterized by sexual reproduction and alternation of generations, although reproduction is also common. There are about 300–315 thousand species of plants, of which the great majority, green plants provide most of the worlds molecular oxygen and are the basis of most of Earths ecologies, especially on land. Plants that produce grains, fruits and vegetables form humankinds basic foodstuffs, Plants play many roles in culture. They are used as ornaments and, until recently and in variety, they have served as the source of most medicines. The scientific study of plants is known as botany, a branch of biology, Plants are one of the two groups into which all living things were traditionally divided, the other is animals. The division goes back at least as far as Aristotle, who distinguished between plants, which generally do not move, and animals, which often are mobile to catch their food. Much later, when Linnaeus created the basis of the system of scientific classification. Since then, it has become clear that the plant kingdom as originally defined included several unrelated groups, however, these organisms are still often considered plants, particularly in popular contexts. When the name Plantae or plant is applied to a group of organisms or taxon. The evolutionary history of plants is not yet settled. Those which have been called plants are in bold, the way in which the groups of green algae are combined and named varies considerably between authors. Algae comprise several different groups of organisms which produce energy through photosynthesis, most conspicuous among the algae are the seaweeds, multicellular algae that may roughly resemble land plants, but are classified among the brown, red and green algae. Each of these groups also includes various microscopic and single-celled organisms
Green plants
–
Green algae from
Ernst Haeckel 's
Kunstformen der Natur, 1904.
Green plants
–
Had'n
Green plants
–
Dicksonia antarctica, a species of
tree fern
Green plants
–
A petrified log in
Petrified Forest National Park.
19.
Algae
–
Algae is an informal term for a large, diverse group of photosynthetic organisms which are not necessarily closely related, and is thus polyphyletic. Included organisms range from unicellular genera, such as Chlorella and the diatoms, to forms, such as the giant kelp. Most are aquatic and autotrophic and lack many of the cell and tissue types, such as stomata, xylem, and phloem. No definition of algae is generally accepted, one definition is that algae have chlorophyll as their primary photosynthetic pigment and lack a sterile covering of cells around their reproductive cells. Some authors exclude all prokaryotes thus do not consider cyanobacteria as algae, Algae constitute a polyphyletic group since they do not include a common ancestor, and although their plastids seem to have a single origin, from cyanobacteria, they were acquired in different ways. Green algae are examples of algae that have primary chloroplasts derived from endosymbiotic cyanobacteria, diatoms and brown algae are examples of algae with secondary chloroplasts derived from an endosymbiotic red alga. Algae exhibit a range of reproductive strategies, from simple asexual cell division to complex forms of sexual reproduction. Algae lack the various structures that characterize land plants, such as the phyllids of bryophytes, rhizoids in nonvascular plants, and the roots, leaves, and other organs found in tracheophytes. Most are phototrophic, although some are mixotrophic, deriving energy both from photosynthesis and uptake of organic carbon either by osmotrophy, myzotrophy, or phagotrophy. Some other heterotrophic organisms, such as the apicomplexans, are derived from cells whose ancestors possessed plastids. Fossilized filamentous algae from the Vindhya basin have been dated back to 1.6 to 1.7 billion years ago, the singular alga is the Latin word for seaweed and retains that meaning in English. Although some speculate that it is related to Latin algēre, be cold, a more likely source is alliga, binding, entwining. The Ancient Greek word for seaweed was φῦκος, which could mean either the seaweed or a red dye derived from it, the Latinization, fūcus, meant primarily the cosmetic rouge. It could be any color, black, red, green, accordingly, the modern study of marine and freshwater algae is called either phycology or algology, depending on whether the Greek or Latin root is used. The name Fucus appears in a number of taxa, most algae contain chloroplasts that are similar in structure to cyanobacteria. Chloroplasts contain circular DNA like that in cyanobacteria and presumably represent reduced endosymbiotic cyanobacteria, however, the exact origin of the chloroplasts is different among separate lineages of algae, reflecting their acquisition during different endosymbiotic events. The table below describes the composition of the three groups of algae. Their lineage relationships are shown in the figure in the upper right, many of these groups contain some members that are no longer photosynthetic
Algae
–
A variety of algae growing on the sea bed in shallow waters
Algae
–
False-color
Scanning electron micrograph of the unicellular
coccolithophore Gephyrocapsa oceanica
Algae
–
The
kelp forest exhibit at the Monterey Bay Aquarium. A three-dimensional, multicellular thallus
Algae
–
Rock lichens in Ireland
20.
Oomycete
–
Oomycota or oomycetes form a distinct phylogenetic lineage of fungus-like eukaryotic microorganisms. They are filamentous, microscopic, absorptive organisms that reproduce sexually and asexually. One oomycete, the mycoparasite Pythium oligandrum, is used for biocontrol, the oomycetes are also often referred to as water molds, although the water-preferring nature which led to that name is not true of most species, which are terrestrial pathogens. The Oomycota have a sparse fossil record. A possible oomycete has been described from Cretaceous amber, the oomycetes rarely have septa, and if they do, they are scarce, appearing at the bases of sporangia, and sometimes in older parts of the filaments. Some are unicellular, but others are filamentous and branching and this group was originally classified among the fungi and later treated as protists, based on general morphology and lifestyle. A cladistic analysis based on modern discoveries about the biology of these organisms supports a close relationship with some photosynthetic organisms, such as brown algae. A common taxonomic classification based on data, places the class Oomycota along with other classes such as Phaeophyceae within the phylum Heterokonta. This relationship is supported by a number of observed differences in the characteristics of oomycetes, for instance, the cell walls of oomycetes are composed of cellulose rather than chitin and generally do not have septations. Also, in the state they have diploid nuclei, whereas fungi have haploid nuclei. Most oomycetes produce self-motile zoospores with two flagella, one flagellum has a whiplash morphology, and the other a branched tinsel morphology. The tinsel flagellum is unique to the Kingdom Heterokonta, spores of the few fungal groups which retain flagella have only one whiplash flagellum. Oomycota and fungi have different metabolic pathways for synthesizing lysine and have a number of enzymes that differ, the ultrastructure is also different, with oomycota having tubular mitochondrial cristae and fungi having flattened cristae. In spite of evidence to the contrary, many species of oomycetes are still described or listed as types of fungi and may sometimes be referred to as pseudofungi. Previously the group was arranged into six orders, the Saprolegniales are the most widespread. Many break down decaying matter, others are parasites, the Leptomitales have wall thickenings that give their continuous cell body the appearance of septation. They bear chitin and often reproduce asexually, the Rhipidiales use rhizoids to attach their thallus to the bed of stagnant or polluted water bodies. The Albuginales are considered by authors to be a family within the Peronosporales
Oomycete
–
A
culture of an oomycete from a stream
Oomycete
–
Water molds
21.
Bacteria
–
Bacteria constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a number of shapes, ranging from spheres to rods, Bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, Bacteria also live in symbiotic and parasitic relationships with plants and animals. Most bacteria have not been characterised, and only half of the bacterial phyla have species that can be grown in the laboratory. The study of bacteria is known as bacteriology, a branch of microbiology, There are typically 40 million bacterial cells in a gram of soil and a million bacterial cells in a millilitre of fresh water. There are approximately 5×1030 bacteria on Earth, forming a biomass which exceeds that of all plants, Bacteria are vital in many stages of the nutrient cycle by recycling nutrients such as the fixation of nitrogen from the atmosphere. The nutrient cycle includes the decomposition of bodies and bacteria are responsible for the putrefaction stage in this process. In March 2013, data reported by researchers in October 2012, was published and it was suggested that bacteria thrive in the Mariana Trench, which with a depth of up to 11 kilometres is the deepest known part of the oceans. Other researchers reported related studies that microbes thrive inside rocks up to 580 metres below the sea floor under 2.6 kilometres of ocean off the coast of the northwestern United States. According to one of the researchers, You can find microbes everywhere—theyre extremely adaptable to conditions, the vast majority of the bacteria in the body are rendered harmless by the protective effects of the immune system, though many are beneficial particularly in the gut flora. However several species of bacteria are pathogenic and cause diseases, including cholera, syphilis, anthrax, leprosy. The most common fatal diseases are respiratory infections, with tuberculosis alone killing about 2 million people per year. In developed countries, antibiotics are used to treat infections and are also used in farming, making antibiotic resistance a growing problem. Once regarded as constituting the class Schizomycetes, bacteria are now classified as prokaryotes. Unlike cells of animals and other eukaryotes, bacterial cells do not contain a nucleus and these evolutionary domains are called Bacteria and Archaea. The ancestors of modern bacteria were unicellular microorganisms that were the first forms of life to appear on Earth, for about 3 billion years, most organisms were microscopic, and bacteria and archaea were the dominant forms of life. In 2008, fossils of macroorganisms were discovered and named as the Francevillian biota, however, gene sequences can be used to reconstruct the bacterial phylogeny, and these studies indicate that bacteria diverged first from the archaeal/eukaryotic lineage. Bacteria were also involved in the second great evolutionary divergence, that of the archaea, here, eukaryotes resulted from the entering of ancient bacteria into endosymbiotic associations with the ancestors of eukaryotic cells, which were themselves possibly related to the Archaea
Bacteria
–
Had'n
Bacteria
Bacteria
–
A
biofilm of thermophilic bacteria in the outflow of
Mickey Hot Springs,
Oregon, approximately 20 mm thick.
Bacteria
–
Helicobacter pylori electron micrograph, showing multiple flagella on the cell surface
22.
Biofilm
–
A biofilm is any group of microorganisms in which cells stick to each other and often these cells adhere to a surface. These adherent cells are embedded within a self-produced matrix of extracellular polymeric substance. Biofilm extracellular polymeric substance, which is referred to as slime, is a polymeric conglomeration generally composed of extracellular DNA, proteins. Biofilms may form on living or non-living surfaces and can be prevalent in natural, industrial and hospital settings. The microbial cells growing in a biofilm are physiologically distinct from planktonic cells of the same organism, when a cell switches to the biofilm mode of growth, it undergoes a phenotypic shift in behavior in which large suites of genes are differentially regulated. Formation of a biofilm begins with the attachment of free-floating microorganisms to a surface, if the colonists are not immediately separated from the surface, they can anchor themselves more permanently using cell adhesion structures such as pili. Some species are not able to attach to a surface on their own but are able to anchor themselves to the matrix or directly to earlier colonists. It is during this colonization that the cells are able to communicate via quorum sensing using products such as N-acyl homoserine lactone, some bacteria are unable to form biofilms as successfully due to their limited motility. Non-motile bacteria cannot recognize the surface or aggregate together as easily as motile bacteria, once colonization has begun, the biofilm grows through a combination of cell division and recruitment. Polysaccharide matrices typically enclose bacterial biofilms, the final stage of biofilm formation is known as dispersion, and is the stage in which the biofilm is established and may only change in shape and size. The development of a biofilm may allow for an aggregate cell colony to be resistant to antibiotics. Cell-cell communication or quorum sensing has shown to be involved in the formation of biofilm in several bacterial species. There are five stages of development, Initial attachment. Dispersal of cells from the colony is an essential stage of the biofilm life cycle. Dispersal enables biofilms to spread and colonize new surfaces, enzymes that degrade the biofilm extracellular matrix, such as dispersin B and deoxyribonuclease, may play a role in biofilm dispersal. Biofilm matrix degrading enzymes may be useful as anti-biofilm agents, recent evidence has shown that a fatty acid messenger, cis-2-decenoic acid, is capable of inducing dispersion and inhibiting growth of biofilm colonies. Secreted by Pseudomonas aeruginosa, this compound induces cyclo heteromorphic cells in species of bacteria. Nitric oxide has also shown to trigger the dispersal of biofilms of several bacteria species at sub-toxic concentrations
Biofilm
–
Staphylococcus aureus biofilm on an indwelling
catheter
Biofilm
–
An
iridescent biofilm on the surface of a fishtank.
Biofilm
–
Five stages of biofilm development: (1) Initial attachment, (2) Irreversible attachment, (3) Maturation I, (4) Maturation II, and (5) Dispersion. Each stage of development in the diagram is paired with a photomicrograph of a developing P. aeruginosa biofilm. All photomicrographs are shown to same scale.
Biofilm
–
Biofilm in
Yellowstone National Park. Longest raised mat area is about half a meter long.
23.
Polymer
–
A polymer is a large molecule, or macromolecule, composed of many repeated subunits. Because of their range of properties, both synthetic and natural polymers play an essential and ubiquitous role in everyday life. Polymers range from familiar synthetic plastics such as polystyrene to natural biopolymers such as DNA and proteins that are fundamental to biological structure, Polymers, both natural and synthetic, are created via polymerization of many small molecules, known as monomers. The units composing polymers derive, actually or conceptually, from molecules of low molecular mass. The term was coined in 1833 by Jöns Jacob Berzelius, though with a distinct from the modern IUPAC definition. The modern concept of polymers as covalently bonded macromolecular structures was proposed in 1920 by Hermann Staudinger, Polymers are studied in the fields of biophysics and macromolecular science, and polymer science. Polyisoprene of latex rubber is an example of a polymer. In biological contexts, essentially all biological macromolecules—i. e, proteins, nucleic acids, and polysaccharides—are purely polymeric, or are composed in large part of polymeric components—e. g. Isoprenylated/lipid-modified glycoproteins, where small molecules and oligosaccharide modifications occur on the polyamide backbone of the protein. The simplest theoretical models for polymers are ideal chains, Polymers are of two types, Natural polymeric materials such as shellac, amber, wool, silk and natural rubber have been used for centuries. A variety of natural polymers exist, such as cellulose. Most commonly, the continuously linked backbone of a used for the preparation of plastics consists mainly of carbon atoms. A simple example is polyethylene, whose repeating unit is based on ethylene monomer, however, other structures do exist, for example, elements such as silicon form familiar materials such as silicones, examples being Silly Putty and waterproof plumbing sealant. Oxygen is also present in polymer backbones, such as those of polyethylene glycol, polysaccharides. Polymerization is the process of combining many small molecules known as monomers into a covalently bonded chain or network, during the polymerization process, some chemical groups may be lost from each monomer. This is the case, for example, in the polymerization of PET polyester, the distinct piece of each monomer that is incorporated into the polymer is known as a repeat unit or monomer residue. Laboratory synthetic methods are divided into two categories, step-growth polymerization and chain-growth polymerization. However, some methods such as plasma polymerization do not fit neatly into either category
Polymer
–
Appearance of real linear polymer chains as recorded using an
atomic force microscope on a surface, under liquid medium. Chain
contour length for this polymer is ~204 nm; thickness is ~0.4 nm.
Polymer
–
A polyethylene sample that has
necked under tension.
Polymer
–
A plastic item with thirty years of exposure to heat and cold, brake fluid, and sunlight. Notice the discoloration, swelling, and
crazing of the material
Polymer
–
Chlorine attack of acetal resin plumbing joint
24.
Cotton
–
Cotton is a soft, fluffy staple fiber that grows in a boll, or protective case, around the seeds of the cotton plants of the genus Gossypium in the mallow family Malvaceae. The fiber is almost pure cellulose, under natural conditions, the cotton bolls will tend to increase the dispersal of the seeds. The plant is a native to tropical and subtropical regions around the world, including the Americas, Africa. The greatest diversity of wild species is found in Mexico, followed by Australia. Cotton was independently domesticated in the Old and New Worlds, the fiber is most often spun into yarn or thread and used to make a soft, breathable textile. Current estimates for world production are about 25 million tonnes or 110 million bales annually, China is the worlds largest producer of cotton, but most of this is used domestically. The United States has been the largest exporter for many years, in the United States, cotton is usually measured in bales, which measure approximately 0.48 cubic meters and weigh 226.8 kilograms. Cotton cultivation in the region is dated to the Indus Valley Civilization, the Indus cotton industry was well-developed and some methods used in cotton spinning and fabrication continued to be used until the industrialization of India. Between 2000 and 1000 BC cotton became widespread across much of India, for example, it has been found at the site of Hallus in Karnataka dating from around 1000 BC. Cotton fabrics discovered in a cave near Tehuacán, Mexico have been dated to around 5800 BC, the domestication of Gossypium hirsutum in Mexico is dated between 3400 and 2300 BC. Cotton was grown upriver, made into nets, and traded with fishing villages along the coast for supplies of fish. The Spanish who came to Mexico and Peru in the early 16th century found the people growing cotton and this may be a reference to tree cotton, Gossypium arboreum, which is a native of the Indian subcontinent. According to the Columbia Encyclopedia, Cotton has been spun, woven and it clothed the people of ancient India, Egypt, and China. Hundreds of years before the Christian era, cotton textiles were woven in India with matchless skill, in Iran, the history of cotton dates back to the Achaemenid era, however, there are few sources about the planting of cotton in pre-Islamic Iran. The planting of cotton was common in Merv, Ray and Pars of Iran, in Persian poets poems, especially Ferdowsis Shahname, there are references to cotton. Marco Polo refers to the products of Persia, including cotton. John Chardin, a French traveler of the 17th century who visited the Safavid Persia, during the Han dynasty, cotton was grown by Chinese peoples in the southern Chinese province of Yunnan. Mohamed Ali Pasha accepted the proposition and granted himself the monopoly on the sale and export of cotton in Egypt, and later dictated cotton should be grown in preference to other crops
Cotton
–
Cotton
Cotton
–
Manually decontaminating cotton before processing at an Indian spinning mill (2010)
Cotton
–
Cotton field
Cotton
–
Cotton plant
25.
Wood
–
Wood is a porous and fibrous structural tissue found in the stems and roots of trees, and other woody plants. It is a material, a natural composite of cellulose fibers which are strong in tension embedded in a matrix of lignin which resists compression. Wood is sometimes defined as only the secondary xylem in the stems of trees, in a living tree it performs a support function, enabling woody plants to grow large or to stand up by themselves. It also conveys water and nutrients between the leaves, other growing tissues, and the roots, Wood may also refer to other plant materials with comparable properties, and to material engineered from wood, or wood chips or fiber. In 2005, the stock of forests worldwide was about 434 billion cubic meters. As an abundant, carbon-neutral renewable resource, woody materials have been of intense interest as a source of renewable energy, in 1991 approximately 3.5 billion cubic meters of wood were harvested. Dominant uses were for furniture and building construction, a 2011 discovery in the Canadian province of New Brunswick discovered the earliest known plants to have grown wood, approximately 395 to 400 million years ago. Wood can be dated by carbon dating and in species by dendrochronology to make inferences about when a wooden object was created. People have used wood for millennia for many purposes, primarily as a fuel or as a material for making houses, tools, weapons, furniture, packaging, artworks. Constructions using wood date back ten thousand years, buildings like the European Neolithic long house were made primarily of wood. Recent use of wood has changed by the addition of steel. The year-to-year variation in tree-ring widths and isotopic abundances gives clues to the climate at that time. This process is known as growth, it is the result of cell division in the vascular cambium, a lateral meristem. These cells then go on to form thickened secondary cell walls, composed mainly of cellulose, hemicellulose, if the distinctiveness between seasons is annual, these growth rings are referred to as annual rings. Where there is little seasonal difference growth rings are likely to be indistinct or absent, if the bark of the tree has been removed in a particular area, the rings will likely be deformed as the plant overgrows the scar. It is usually lighter in color than that near the portion of the ring. The outer portion formed later in the season is known as the latewood or summerwood. However, there are differences, depending on the kind of wood
Wood
–
Diagram of
secondary growth in a
tree showing idealised vertical and horizontal sections. A new layer of wood is added in each growing season, thickening the stem, existing branches and
roots, to form a
growth ring.
Wood
Wood
–
A knot on a tree at the
Garden of the Gods public park in
Colorado Springs, Colorado (October 2006)
Wood
–
Wood knot in vertical section
26.
Hemp
–
A nuclear electromagnetic pulse is a characteristic burst of electromagnetic radiation created by nuclear explosions. The resulting rapidly changing electric and magnetic fields may couple with electrical and electronic systems to produce damaging current, the specific characteristics of any particular nuclear EMP event vary according to a number of factors, the most important of which is the altitude of the detonation. The term electromagnetic pulse generally excludes optical and ionizing ranges, in military terminology, a nuclear warhead detonated hundreds of kilometers above the Earths surface is known as a high-altitude electromagnetic pulse device. The fact that a pulse is produced by a nuclear explosion was known in the earliest days of nuclear weapons testing. The magnitude of the EMP and the significance of its effects, during the first United States nuclear test on 16 July 1945, electronic equipment was shielded because Enrico Fermi expected the electromagnetic pulse. The official technical history for that first nuclear test states, All signal lines were completely shielded, in spite of this many records were lost because of spurious pickup at the time of the explosion that paralyzed the recording equipment. During British nuclear testing in 1952–1953 instrumentation failures were attributed to radioflash, the first openly reported observation of the unique aspects of high-altitude nuclear EMP occurred during the helium balloon lofted Yucca nuclear test of the Hardtack I series on 28 April 1958. In that test, the field measurements from the 1.7 kiloton weapon went off the scale of the test instruments and was estimated to be about 5 times the oscilloscope limits. The Yucca EMP was initially positive-going whereas low-altitude bursts were negative pulses, also, the polarization of the Yucca EMP signal was horizontal, whereas low-altitude nuclear EMP was vertically polarized. In spite of many differences, the unique EMP results were dismissed as a possible wave propagation anomaly. The larger scientific community aware of the significance of the EMP problem after a three-article series on nuclear EMP was published in 1981 by William J. Broad in Science. In July 1962, the US carried out the Starfish Prime test and this demonstrated that the effects of a high-altitude nuclear explosion were much larger than had been previously calculated. Starfish Prime was the first success in the series of United States high-altitude nuclear tests in 1962 known as Operation Fishbowl, subsequent tests gathered more data on the high-altitude EMP phenomenon. The EMP damage of the Starfish Prime test was quickly repaired because of the ruggedness of Hawaiis electrical and these calculations, combined with the accelerating reliance on EMP-sensitive microelectronics, heightened awareness that EMP could be a significant problem. In 1962, the Soviet Union also performed three EMP-producing nuclear tests in space over Kazakhstan, the last in the Soviet Project K nuclear tests. The geomagnetic storm–like E3 pulse from Test 184 induced a current surge in an underground power line that caused a fire in the power plant in the city of Karaganda. After the collapse of the Soviet Union, the level of damage was communicated informally to U. S. scientists. After the 1991 collapse of the Soviet Union, there was a period of a few years of cooperation between United States and Russian scientists on the HEMP phenomenon
Hemp
27.
Paperboard
–
Paperboard is a thick paper-based material. While there is no differentiation between paper and paperboard, paperboard is generally thicker than paper. According to ISO standards, paperboard is a paper with a grammage above 224 g/m2, Paperboard can be single- or multi-ply. Paperboard can be cut and formed, is lightweight. Another end-use would be graphic printing, such as book and magazine covers or postcards, sometimes it is referred to as cardboard, which is a generic, lay term used to refer to any heavy paper pulp–based board. Paperboard is also used in fine arts for creating sculptures, in 1817, the first paperboard carton was produced in England. Folding cartons first emerged around the 1860s and were shipped flat to save space,1879 saw the development of mechanical die cutting and creasing of blanks. In 1911 the first kraft sulphate mill was built in Florida and in 1915 the gable top milk carton was patented, ovenable paperboard was introduced in 1974. Terminology and classifications of paperboard are not always uniform, differences occur depending on specific industry, locale, and personal choice. It is the covering over the corrugating medium. Other Binders board – a paperboard used in bookbinding for making hardcovers, pulp board are produced on pulping machines that can handle higher grammage and several plies. The above-mentioned fibrous material can come from fresh sources or from recycled waste paper. Around 90% of virgin paper is made from wood pulp and it is now mandatory in many countries for paper-based packaging to be manufactured wholly or partially from recycled material. Raw materials include, Hardwood, Ca.0.05 inches in length e. g. Birch which has short fibres and it is generally more difficult to work with, however, it does provide higher tensile strength, but lower tear and other strength properties. Although its fibres are not as long and strong as those in softwood, Hardwood fibres fill the sheet better and therefore make a smoother paper that is more opaque and better for printing. Hardwood makes an excellent corrugating medium, softwood, Ca.0.13 inches in length e. g. Pine and spruce which have typically long fibres and make superior paperboard in services where strength is important. Recycled, Used paper is collected and sorted and usually mixed with virgin fibres in order to new material. This is necessary as the recycled fibre often loses strength when reused, mixed waste paper is not usually deinked for paperboard manufacture and hence the pulp may contain traces of inks, adhesives, and other residues which together give it a grey colour
Paperboard
–
Corrugated fiberboard made from paperboard
Paperboard
–
Sculpture made of massive paperboard by
Herbert Wetterauer
28.
Paper
–
Paper is a thin material produced by pressing together moist fibres of cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets. It is a material with many uses, including writing, printing, packaging, cleaning. The modern pulp and paper industry is global, with China leading its production, the oldest known archaeological fragments of the immediate precursor to modern paper, date to the 2nd century BC in China. The pulp papermaking process is ascribed to Cai Lun, a 2nd-century AD Han court eunuch, with paper as an effective substitute for silk in many applications, China could export silk in greater quantity, contributing to a Golden Age. Because of papers introduction to the West through the city of Baghdad, in the 19th century, industrial manufacture greatly lowered its cost, enabling mass exchange of information and contributing to significant cultural shifts. In 1844, the Canadian inventor Charles Fenerty and the German F. G. Keller independently developed processes for pulping wood fibres, before the industrialisation of the paper production the most common fibre source was recycled fibres from used textiles, called rags. The rags were from hemp, linen and cotton, a process for removing printing inks from recycled paper was invented by German jurist Justus Claproth in 1774. Today this method is called deinking and it was not until the introduction of wood pulp in 1843 that paper production was not dependent on recycled materials from ragpickers. The word paper is etymologically derived from Latin papyrus, which comes from the Greek πάπυρος, although the word paper is etymologically derived from papyrus, the two are produced very differently and the development of the first is distinct from the development of the second. Papyrus is a lamination of natural plant fibres, while paper is manufactured from fibres whose properties have changed by maceration. To make pulp from wood, a chemical pulping process separates lignin from cellulose fibres and this is accomplished by dissolving lignin in a cooking liquor, so that it may be washed from the cellulose, this preserves the length of the cellulose fibres. Paper made from chemical pulps are also known as wood-free papers–not to be confused with paper, this is because they do not contain lignin. The pulp can also be bleached to produce paper, but this consumes 5% of the fibres, chemical pulping processes are not used to make paper made from cotton. There are three main chemical pulping processes, the process dates back to the 1840s and it was the dominant method extent before the second world war. Most pulping operations using the process are net contributors to the electricity grid or use the electricity to run an adjacent paper mill. Another advantage is that this process recovers and reuses all inorganic chemical reagents, soda pulping is another specialty process used to pulp straws, bagasse and hardwoods with high silicate content. There are two major mechanical pulps, thermomechanical pulp and groundwood pulp, in the TMP process, wood is chipped and then fed into steam heated refiners, where the chips are squeezed and converted to fibres between two steel discs. In the groundwood process, debarked logs are fed into grinders where they are pressed against rotating stones to be made into fibres
Paper
–
Different types of paper:
carton,
tissue paper
Paper
–
Hemp wrapping paper, China, circa 100 BC.
Paper
–
The microscopic structure of paper:
Micrograph of paper
autofluorescing under
ultraviolet illumination. The individual fibres in this sample are around 10
µm in diameter.
Paper
–
Card and paper stock for
crafts use comes in a wide variety of textures and colors.
29.
Cellophane
–
Cellophane is a thin, transparent sheet made of regenerated cellulose. Its low permeability to air, oils, greases, bacteria, Cellophane is in many countries a registered trade mark of Innovia Films Ltd based in Wigton, Cumbria, United Kingdom. The film is passed through several more baths, one to remove sulfur, one to bleach the film. A similar process, using a hole instead of a slit, is used to make a fibre called rayon, chemically, cellophane, rayon and cellulose are polymers of glucose and contain the chemical elements carbon, hydrogen and oxygen. Cellophane was invented by Swiss chemist Jacques E. Brandenberger while employed by Blanchisserie et Teinturerie de Thaon, in 1900, inspired by seeing a wine spill on a restaurants tablecloth, he decided to create a cloth that could repel liquids rather than absorb them. His first step was to spray a waterproof coating onto fabric, the resultant coated fabric was far too stiff, but the clear film easily separated from the backing cloth, and he abandoned his original idea as the possibilities of the new material became apparent. It took ten years for Brandenberger to perfect his film, his chief improvement over earlier work with films being to add glycerin to soften the material. By 1912 he had constructed a machine to manufacture the film, the following year, the company Comptoir des Textiles Artificiels bought the Thaon firms interest in Cellophane and established Brandenberger in a new company, La Cellophane SA. Whitmans candy company initiated use of cellophane for candy wrapping in the United States in 1912 for their Whitmans Sampler and they remained the largest user of imported cellophane from France until nearly 1924, when DuPont built the first cellophane manufacturing plant in the US. Cellophane saw limited sales in the US at first since while it was waterproof and this meant that it was unsuited to packaging products that required moisture proofing. DuPont hired chemist William Hale Charch, who spent three years developing a nitrocellulose lacquer that, when applied to Cellophane, made it moisture proof. Following the introduction of moisture-proof Cellophane in 1927, the materials sales tripled between 1928 and 1930, and in 1938, Cellophane accounted for 10% of DuPonts sales and 25% of its profits. The British textile company Courtaulds viscose technology had allowed it to diversify in 1930 into viscose film, however, competition with Cellophane was an obstacle to its sales, and in 1935 it founded British Cellophane Limited in conjunction with the Cellophane Company and its French parent company CTA. A major production facility was constructed at Bridgwater, Somerset, England, from 1935 to 1937, BCL subsequently constructed plants in Cornwall, Ontario, as an adjunct to the existing Courtaulds viscose rayon plant there, and in 1957 at Barrow-in-Furness, Cumbria. Those last two plants were closed in the 1990s, cellulose film has been manufactured continuously since the mid-1930s and is still used today. In the UK and in other countries, cellophane is a registered trademark. Cellophane sales have dwindled since the 1960s, due to alternative packaging options, when placed between two plane polarizing filters, cellophane produces prismatic colours due to its birefringent nature. Artists have used this effect to create stained glass-like creations that are kinetic and interactive
Cellophane
–
Printed cellophane bag with
chocolate hearts and a transparent cellophane packaging with
gingerbread
30.
Rayon
–
Rayon is a manufactured regenerated cellulose fiber. It is made from purified cellulose, primarily from wood pulp and it is then dissolved and forced through a spinneret to produce filaments which are chemically solidified, resulting in synthetic fibers of nearly pure cellulose. Because rayon is manufactured from naturally occurring polymers, it is considered a semi-synthetic fiber, specific types of rayon include viscose, modal and lyocell, each of which differs in manufacturing process and properties of the finished product. The solubility of nitrocellulose in organic solvents such as ether and acetone was the basis for the first artificial silk by Georges Audemars in about 1855, commercial production started in 1891, but the result was flammable and more expensive than cellulose acetate or cuprammonium rayon. Because of this expense, production ceased early in the 1900s, nitrocellulose was briefly known as mother-in-law silk. Nathan Rosenstein invented the process by which he turned rayon from a hard fiber to a fabric. This allowed rayon to become a popular raw material in textiles, paul Schützenberger discovered that cellulose reacts with acetic anhydride to form cellulose acetate. The triacetate is soluble only in making the method expensive. The discovery that hydrolyzed cellulose acetate is soluble in polar solvents, like acetone, made production of cellulose acetate fibers cheap. The Swiss chemist Matthias Eduard Schweizer discovered that dissolved in tetraaminecopper dihydroxide. Max Fremery and Johann Urban developed a method to produce carbon fibers for use in light bulbs in 1897, Production of cuprammonium rayon for textiles started in 1899 in the Vereinigte Glanzstoff Fabriken AG in Oberbruch near Aachen. Improvement by the J. P. Bemberg AG in 1904 made the artificial silk a product comparable to real silk, in 1894, English chemist Charles Frederick Cross, and his collaborators Edward John Bevan, and Clayton Beadle patented their artificial silk. They named their material viscose, because its production involved the intermediacy of a viscous solution. The process built on the reaction of cellulose with a strong base, the xanthate is then converted back to a cellulose fiber in a subsequent step. The first commercial viscose rayon was produced by the U. K. company Courtaulds Fibres in 1905, Courtaulds formed an American division, American Viscose, to produce their formulation in the United States in 1910. The name rayon was adopted in 1924, with viscose being used for the organic liquid used to make both rayon and cellophane. In Europe, though, the fabric itself became known as viscose, the viscose method can use wood as a source of cellulose, whereas other routes to rayon require lignin-free cellulose as starting material. The use of sources of cellulose makes viscose cheaper, so it was used on a larger scale than the other methods
Rayon
–
A device for spinning Viscose Rayon dating from 1901
Rayon
–
A sample of rayon from a skirt, photographed with a
macro lens.
Rayon
31.
Energy crop
–
An energy crop is a plant grown as a low-cost and low-maintenance harvest used to make biofuels, such as bioethanol, or combusted for its energy content to generate electricity or heat. Energy crops are generally categorized as woody or herbaceous plants, many of the latter are grasses of the family Graminaceae, commercial energy crops are typically densely planted, high-yielding crop species which are processed to bio-fuel and burnt to generate power. Woody crops such as willow or poplar are widely utilised, as well as grasses such as Miscanthus. Through genetic modification and application of biotechnology plants can be manipulated to create greater yields, reduce associated costs, high energy yield can also be realized with existing cultivars. Energy generated by burning plants grown for the purpose, often after the dry matter is pelletized, Energy crops are used for firing power plants, either alone or co-fired with other fuels. Alternatively they may be used for heat or combined heat and power production, to cover the increasing requirements of woody biomass, short rotation coppice were applied to agricultural sites. Within this cropping systems fast growing species like willows and poplars are planted in growing cycles of three to five years. The cultivation of this cultures is dependent on wet soil conditions, however, an influence on local water conditions could not be excluded. This indicates that an establishment should exclude the vicinity to vulnarable wetland ecosystems, anaerobic digesters or biogas plants can be directly supplemented with energy crops once they have been ensiled into silage. The fastest growing sector of German biofarming has been in the area of Renewable Energy Crops on nearly 500,000 ha of land, Energy crops can also be grown to boost gas yields where feedstocks have a low energy content, such as manures and spoiled grain. It is estimated that the energy yield presently of bioenergy crops converted via silage to methane is about 2 GWh/km2. Small mixed cropping enterprises with animals can use a portion of their acreage to grow and convert energy crops, in Europe and especially Germany, however, this rapid growth has occurred only with substantial government support, as in the German bonus system for renewable energy. European production of biodiesel from energy crops has grown steadily in the last decade, principally focused on rapeseed used for oil, production of oil/biodiesel from rape covers more than 12,000 km² in Germany alone, and has doubled in the past 15 years. Biodiesel yield of soybeans is significantly lower than that of rape, Energy crops for biobutanol are grasses. Two leading non-food crops for the production of cellulosic bioethanol are switchgrass, there has been a preoccupation with cellulosic bioethanol in America as the agricultural structure supporting biomethane is absent in many regions, with no credits or bonus system in place. Consequently, a lot of money and investor hopes are being pinned on marketable and patentable innovations in enzyme hydrolysis. New developments in converting grain stillage into biogas energy looks promising as a means to improve the energy ratio of this type of bioethanol process. Dedicated energy crops are non-food energy crops as giant miscanthus, switchgrass, jatropha, fungi, dedicated energy crops are promising cellulose sources that can be sustainably produced in many regions of the United States
Energy crop
–
A
Department for Environment, Food and Rural Affairs energy crops scheme plantation in the United Kingdom. Energy
crops of this sort can be used in conventional power stations or specialised electricity generation units, reducing the amount of
fossil fuel -derived
carbon dioxide emissions.
Energy crop
–
Elephant grass (
Miscanthus sinensis) is an experimental energy crop
Energy crop
–
Coconuts sun-dried in
Kozhikode,
Kerala for making copra, the dried meat, or kernel, of the
coconut.
Coconut oil extracted from it has made copra an important agricultural commodity for many coconut-producing countries. It also yields coconut cake which is mainly used as
feed for livestock.
Energy crop
–
Pure biodiesel (B-100), made from soybeans
32.
Biofuel
–
Biofuels can be derived directly from plants, or indirectly from agricultural, commercial, domestic, and/or industrial wastes. Renewable biofuels generally involve contemporary carbon fixation, such as those that occur in plants or microalgae through the process of photosynthesis, other renewable biofuels are made through the use or conversion of biomass. This biomass can be converted to convenient energy-containing substances in three different ways, thermal conversion, chemical conversion, and biochemical conversion and this biomass conversion can result in fuel in solid, liquid, or gas form. This new biomass can also be used directly for biofuels, bioethanol is an alcohol made by fermentation, mostly from carbohydrates produced in sugar or starch crops such as corn, sugarcane, or sweet sorghum. Cellulosic biomass, derived from sources, such as trees and grasses, is also being developed as a feedstock for ethanol production. Ethanol can be used as a fuel for vehicles in its pure form, bioethanol is widely used in the USA and in Brazil. Current plant design does not provide for converting the portion of plant raw materials to fuel components by fermentation. Biodiesel is produced from oils or fats using transesterification and is the most common biofuel in Europe, in 2010, worldwide biofuel production reached 105 billion liters, up 17% from 2009, and biofuels provided 2. 7% of the worlds fuels for road transport. Global ethanol fuel production reached 86 billion liters in 2010, with the United States and Brazil as the top producers. The worlds largest biodiesel producer is the European Union, accounting for 53% of all production in 2010. As of 2011, mandates for blending biofuels exist in 31 countries at the national level, the International Energy Agency has a goal for biofuels to meet more than a quarter of world demand for transportation fuels by 2050 to reduce dependence on petroleum and coal. The production of biofuels also led into an automotive industry. There are various social, economic, environmental and technical issues relating to production and use. Most transportation fuels are liquids, because vehicles usually require high energy density and this occurs naturally in liquids and solids. High energy density can also be provided by a combustion engine. The fuels that are easiest to burn cleanly are typically liquids, thus, liquids meet the requirements of being both energy-dense and clean-burning. In addition, liquids can be pumped, which means handling is easily mechanized, first-generation or conventional biofuels are made from sugar, starch, or vegetable oil. Biobutanol is often claimed to provide a replacement for gasoline
Biofuel
–
A bus fueled by
biodiesel
Biofuel
–
Information on pump regarding
ethanol fuel blend up to 10%,
California
Biofuel
–
Neat ethanol on the left (A),
gasoline on the right (G) at a
filling station in
Brazil
Biofuel
–
Walmart 's truck fleet logs millions of miles each year, and the company planned to double the fleet's efficiency between 2005 and 2015. This truck is one of 15 based at Walmart's
Buckeye, Arizona distribution center that was converted to run on a biofuel made from reclaimed cooking grease produced during food preparation at Walmart stores.
33.
Cellulosic ethanol
–
Cellulosic ethanol is ethanol produced from cellulose rather than from the plants seeds or fruit. It is a biofuel produced from grasses, wood, algae, the fibrous parts of the plants are mostly inedible to animals, including humans, except for ruminants. Considerable interest in cellulosic ethanol exists because it has the potential for strong economic importance, growth of cellulose by plants is a mechanism that captures and stores solar energy chemically in nontoxic ways with resultant supplies that are easy to transport and store. Additionally, transport may be unneeded anyway, because grasses or trees can grow almost anywhere temperate, potential exists for the many benefits of carbonaceous liquid fuels and petrochemicals but in a carbon cycle–balanced and renewable way. To date, what stands in the way of these goals is that production of alcohol is not yet sufficiently practical on a commercial scale. Cellulosic ethanol is a type of biofuel produced from lignocellulose, a material that comprises much of the mass of plants. Lignocellulose is composed mainly of cellulose, hemicellulose and lignin, corn stover, Panicum virgatum, Miscanthus grass species, wood chips and the byproducts of lawn and tree maintenance are some of the more popular cellulosic materials for ethanol production. Switchgrass and Miscanthus are the major biomass materials being studied today, one of the benefits of cellulosic ethanol is it reduces greenhouse gas emissions by 85% over reformulated gasoline. By contrast, starch ethanol, which most frequently uses natural gas to energy for the process. According to the National Academy of Sciences in 2011, there is no commercially viable bio-refinery in existence to convert lignocellulosic biomass to fuel, the French chemist, Henri Braconnot, was the first to discover that cellulose could be hydrolyzed into sugars by treatment with sulfuric acid in 1819. The hydrolyzed sugar could then be processed to form ethanol through fermentation, the first commercialized ethanol production began in Germany in 1898, where acid was used to hydrolyze cellulose. In the United States, the Standard Alcohol Company opened the first cellulosic ethanol plant in South Carolina in 1910. Later, a plant was opened in Louisiana. However, both plants were closed after World War I due to economic reasons, the first attempt at commercializing a process for ethanol from wood was done in Germany in 1898. It involved the use of acid to hydrolyze the cellulose to glucose. The Germans soon developed an industrial process optimized for yields of around 50 US gallons per ton of biomass and this process soon found its way to the US, culminating in two commercial plants operating in the southeast during World War I. These plants used what was called the American Process — a one-stage dilute sulfuric acid hydrolysis, though the yields were half that of the original German process, the throughput of the American process was much higher. A drop in lumber production forced the plants to close shortly after the end of World War I, in the meantime, a small but steady amount of research on dilute acid hydrolysis continued at the USFSs Forest Products Laboratory
Cellulosic ethanol
–
Bioreactor for cellulosic ethanol research.
Cellulosic ethanol
–
Fluidized Bed Gasifier in
Güssing Burgenland Austria
Cellulosic ethanol
–
Biofuels
34.
Wood pulp
–
Pulp is a lignocellulosic fibrous material prepared by chemically or mechanically separating cellulose fibres from wood, fiber crops or waste paper. The wood fiber sources required for pulping are 45% sawmill residue, 21% logs and chips, many kinds of paper are made from wood with nothing else mixed into them. This includes newspaper, magazines and even toilet paper, Pulp is one of the most abundant raw materials worldwide. Using wood to make paper is a recent innovation. The ancient Egyptians were the first to make paper from reeds, papermaking using cotton and linen fibers spread to Europe in the 13th century, and the increasing use of fabric brought more rag paper, which was a factor in the development of printing. By the 1800s, fibre crops such as flax, which provided linen fibres, were still the material source. Chemical processes quickly followed, first with J. Roths use of acid to treat wood, then by Benjamin Tilghmans U. S. patent on the use of calcium bisulfite, Ca2. Almost a decade later, the first commercial sulfite pulp mill was built and it used magnesium as the counter ion and was based on work by Carl Daniel Ekman. By 1900, sulfite pulping had become the dominant means of producing wood pulp, the competing chemical pulping process, the sulfate, or kraft, process, was developed by Carl F. Dahl in 1879, the first kraft mill started, in Sweden, in 1890. The invention of the boiler, by G. H. Tomlinson in the early 1930s, allowed kraft mills to recycle almost all of their pulping chemicals, global production of wood pulp in 2006 was 175 million tons. In the previous year,63 million tons of market pulp was sold, with Canada being the largest source at 21 percent of the total, chemical pulp made up 93 percent of market pulp. The timber resources used to make wood pulp are referred to as pulpwood, wood pulp comes from softwood trees such as spruce, pine, fir, larch and hemlock, and hardwoods such as eucalyptus, aspen and birch. A pulp mill is a facility that converts wood chips or other plant fibre source into a thick fiberboard which can be shipped to a paper mill for further processing. Pulp can be manufactured using mechanical, semi-chemical or fully chemical methods, the finished product may be either bleached or non-bleached, depending on the customer requirements. Wood and other plant materials used to make pulp contain three components, cellulose fibers, lignin and hemicelluloses. The aim of pulping is to break down the structure of the fibre source, be it chips, stems or other plant parts. The various mechanical pulping methods, such as groundwood and refiner mechanical pulping, much of the lignin remains adhering to the fibres
Wood pulp
–
Structure of fibres of pulp
Wood pulp
–
Pulp at a paper mill near Pensacola, 1947
Wood pulp
–
Fibres in wood pulp
Wood pulp
–
International Paper Company. Pulp mill that makes
fluff pulp for use in
absorbent products with the
kraft process.
35.
Ruminant
–
Ruminants are mammals that are able to acquire nutrients from plant-based food by fermenting it in a specialized stomach prior to digestion, principally through microbial actions. The process typically requires the fermented ingesta to be regurgitated and chewed again, the process of rechewing the cud to further break down plant matter and stimulate digestion is called rumination. The word ruminant comes from the Latin ruminare, which means to chew over again, the roughly 150 species of ruminants includes both domestic and wild species. Ruminating mammals include cattle, goats, sheep, giraffes, yaks, deer, antelope and it has also been suggested that notoungulates also relied on rumination, as opposed to other antlantogenates that relied on the more typical hindgut fermentation, though this is not entirely certain. Taxonomically, the suborder Ruminantia is a lineage of herbivorous artiodactyls that includes the most advanced, the term ruminant is not synonymous with Ruminantia. The suborder Ruminantia includes many ruminant species, but does not include tylopods, the primary difference between a ruminant and nonruminant is that ruminants have a four-compartment stomach. The four parts are the rumen, reticulum, omasum, in the first two chambers, the rumen and the reticulum, the food is mixed with saliva and separates into layers of solid and liquid material. Solids clump together to form the cud or bolus, the cud is then regurgitated and chewed to completely mix it with saliva and to break down the particle size. Fiber, especially cellulose and hemicellulose, is broken down in these chambers by microbes into the three volatile fatty acids, acetic acid, propionic acid, and butyric acid. Protein and nonstructural carbohydrate are also fermented, though the rumen and reticulum have different names, they represent the same functional space as digesta can move back and forth between them. Together, these chambers are called the reticulorumen, after this, the digesta is moved to the true stomach, the abomasum. The abomasum is the equivalent of the monogastric stomach. Digesta is finally moved into the intestine, where the digestion and absorption of nutrients occurs. Microbes produced in the reticulorumen are also digested in the small intestine, fermentation continues in the large intestine in the same way as in the reticulorumen. Only small amounts of glucose are absorbed from dietary carbohydrates, most dietary carbohydrates are fermented into VFAs in the rumen. The VFA propionate is used for around 70% of the glucose and glycogen produced, also, some mammals are pseudoruminants, which have a three-compartment stomach instead of four like ruminants. Pseudoruminants, like traditional ruminants, are foregut fermentors and most ruminate or chew cud, however, their anatomy and method of digestion differs significantly from that of a four-chambered ruminant. Monogastric herbivores, such as rhinoceroses, horses, and rabbits, are not ruminants and these hindgut fermenters digest cellulose in an enlarged cecum through the reingestion of the cecotrope
Ruminant
–
Food digestion in the simple stomach of nonruminant animals versus ruminants
Ruminant
–
Rough illustration of a ruminant digestive system
36.
Termite
–
Termites are eusocial insects that are classified at the taxonomic rank of infraorder Isoptera, or as epifamily Termitoidae within the cockroach order Blattodea. Termites were once classified in an order from cockroaches. However, the first termites emerged during the Permian or even the Carboniferous. About 3,106 species are described, with a few hundred more left to be described. Although these insects are called white ants, they are not ants. Like ants and some bees and wasps from the separate order Hymenoptera, all colonies have fertile males called kings and one or more fertile females called queens. Termites mostly feed on plant material and cellulose, generally in the form of wood, leaf litter, soil. Termites are major detritivores, particularly in the subtropical and tropical regions, Termites are among the most successful groups of insects on Earth, colonising most landmasses except for Antarctica. Their colonies range in size from a few hundred individuals to enormous societies with several million individuals, Termite queens have the longest lifespan of any insect in the world, with some queens reportedly living up to 30 to 50 years. Unlike ants, which undergo a metamorphosis, each individual termite goes through an incomplete metamorphosis that proceeds through egg, nymph. Colonies are described as superorganisms because the termites form part of a self-regulating entity, Termites are a delicacy in the diet of some human cultures and are used in many traditional medicines. Several hundred species are significant as pests that can cause serious damage to buildings, crops. Some species, such as the West Indian drywood termite, are regarded as invasive species, the infraorder name Isoptera is derived from the Greek words iso and ptera, which refers to the nearly equal size of the fore and hind wings. Termite derives from the Latin and Late Latin word termes, altered by the influence of Latin terere from the earlier word tarmes, Termite nests were commonly known as terminarium or termitaria. In early English, termites were known as wood ants or white ants, the modern term was first used in 1781. DNA analysis from 16S rRNA sequences has supported a hypothesis, originally suggested by Cleveland and colleagues in 1934 and this earlier conclusion had been based on the similarity of the symbiotic gut flagellates in the wood-eating cockroaches to those in certain species of termites regarded as living fossils. In the 1960s additional evidence supporting that hypothesis emerged when F. A. McKittrick noted similar morphological characteristics between some termites and Cryptocercus nymphs. These similarities have led some authors to propose that termites be reclassified as a family, the Termitidae, within the order Blattodea
Termite
Termite
–
The external appearance of the giant northern termite Mastotermes darwiniensis is suggestive of the close relationship between termites and cockroaches
Termite
–
Fossilised
Nanotermes isaacae termite alate in Cambay amber
Termite
–
Close-up view of a worker's head
37.
Digestion
–
Digestion is the breakdown of large insoluble food molecules into small water-soluble food molecules so that they can be absorbed into the watery blood plasma. In certain organisms, these substances are absorbed through the small intestine into the blood stream. Digestion is a form of catabolism that is divided into two processes based on how food is broken down, mechanical and chemical digestion. The term mechanical digestion refers to the breakdown of large pieces of food into smaller pieces which can subsequently be accessed by digestive enzymes. In chemical digestion, enzymes break down food into the small molecules the body can use. In the human system, food enters the mouth and mechanical digestion of the food starts by the action of mastication, a form of mechanical digestion. After undergoing mastication and starch digestion, the food will be in the form of a small and it will then travel down the esophagus and into the stomach by the action of peristalsis. Gastric juice in the stomach starts protein digestion, gastric juice mainly contains hydrochloric acid and pepsin. As these two chemicals may damage the stomach wall, mucus is secreted by the stomach, providing a slimy layer that acts as a shield against the effects of the chemicals. At the same time protein digestion is occurring, mechanical mixing occurs by peristalsis and this allows the mass of food to further mix with the digestive enzymes. After some time, the resulting liquid is called chyme. When the chyme is fully digested, it is absorbed into the blood, 95% of absorption of nutrients occurs in the small intestine. Water and minerals are reabsorbed back into the blood in the colon where the pH is slightly acidic about 5.6 ~6.9, some vitamins, such as biotin and vitamin K produced by bacteria in the colon are also absorbed into the blood in the colon. Waste material is eliminated from the rectum during defecation, there is a fundamental distinction between internal and external digestion. External digestion developed earlier in history, and most fungi still rely on it. In this process, enzymes are secreted into the environment surrounding the organism, where they break down an organic material, some organisms, including nearly all spiders, simply secrete biotoxins and digestive chemicals into the extracellular environment prior to ingestion of the consequent soup. Bacteria use several systems to obtain nutrients from other organisms in the environments, in a channel transupport system, several proteins form a contiguous channel traversing the inner and outer membranes of the bacteria. It is a system, which consists of only three protein subunits, the ABC protein, membrane fusion protein, and outer membrane protein
Digestion
–
Venus Flytrap (Dionaea muscipula) leaf
Digestion
Digestion
–
Trophozoites of Entamoeba histolytica with ingested erythrocytes
Digestion
–
A
Catalina Macaw 's seed-shearing beak
38.
Symbiosis
–
Symbiosis is any type of a close and long-term biological interaction between two different species, be it mutualistic, commensalistic, or parasitic. In 1879, Heinrich Anton de Bary defined it as the living together of unlike organisms, Symbiosis can be obligatory, which means that one or both of the symbionts entirely depend on each other for survival, or facultative when they can generally live independently. When one organism lives on another such as mistletoe, it is called ectosymbiosis, or endosymbiosis when one partner lives inside the tissues of another, as in Symbiodinium in corals. In 1877, Albert Bernhard Frank used the term symbiosis which previously had used to depict people living together in community to describe the mutualistic relationship in lichens. In 1879, the German mycologist Heinrich Anton de Bary defined it as the living together of unlike organisms, symbiotic relationships can be obligate, meaning that one or both of the symbionts entirely depend on each other for survival. For example, in lichens, which consist of fungal and photosynthetic symbionts, the algal or cyanobacterial symbionts in lichens, such as Trentepohlia, can generally live independently, and their symbiosis is, therefore, facultative. Endosymbiosis is any relationship in which one symbiont lives within the tissues of the other, either within the cells or extracellularly. Mutualism or interspecies reciprocal altruism is a relationship between individuals of different species where both individuals benefit, in general, only lifelong interactions involving close physical and biochemical contact can properly be considered symbiotic. Mutualistic relationships may be either obligate for both species, obligate for one but facultative for the other, or facultative for both, a large percentage of herbivores have mutualistic gut flora to help them digest plant matter, which is more difficult to digest than animal prey. This gut flora is made up of cellulose-digesting protozoans or bacteria living in the herbivores intestines, coral reefs are the result of mutualisms between coral organisms and various types of algae which live inside them. Most land plants and land ecosystems rely on mutualisms between the plants, which fix carbon from the air, and mycorrhyzal fungi, which help in extracting water, an example of mutual symbiosis is the relationship between the ocellaris clownfish that dwell among the tentacles of Ritteri sea anemones. The territorial fish protects the anemone from anemone-eating fish, and in turn the stinging tentacles of the anemone protect the clownfish from its predators, a special mucus on the clownfish protects it from the stinging tentacles. A further example is the fish, which sometimes lives together with a shrimp. The shrimp digs and cleans up a burrow in the sand in which both the shrimp and the fish live. The shrimp is almost blind, leaving it vulnerable to predators when outside its burrow, in case of danger the goby fish touches the shrimp with its tail to warn it. When that happens both the shrimp and goby fish quickly retreat into the burrow, different species of gobies also exhibit mutualistic behavior through cleaning up ectoparasites in other fish. Another non-obligate symbiosis is known from encrusting bryozoans and hermit crabs, the bryozoan colony develops a cirumrotatory growth and offers the crab a helicospiral-tubular extension of its living chamber that initially was situated within a gastropod shell. A spectacular examples of mutualism is between the siboglinid tube worms and symbiotic bacteria that live at hydrothermal vents and cold seeps
Symbiosis
Symbiosis
–
Alder tree root nodule
Symbiosis
–
Hermit crab, Calcinus laevimanus, with sea anemone.
Symbiosis
–
Bryoliths document a mutualistic symbiosis between a
hermit crab and encrusting
bryozoans;
Banc d'Arguin,
Mauritania
39.
Trichonympha
–
Trichonympha is a genus of parabasalid excavates that live in the intestines of many, if not most, termite species. They are symbiotes, in that break down the cellulose in the wood. Trichonympha - it resembles teardrops or pears that are wearing wigs and they are extremely motile, and fed by engulfing wood and plant fibers through phagocytosis, which always occurs at the broad ends of their bodies. As beguiling as a relationship between an insect and its wood-digesting symbiote may seem, further investigations of Trichonympha reveals even more mind-boggling situations. The presence of spirochete ectosymbiotes embedded in its membrane, and together with Trichonymphas own flagella, give the protist its characteristic wiggy appearance. Another extremely similar metamonad termite symbiote is Mixotricha paradoxa, guichard, P. Desfosses, A. Maheshwari, A. Hachet, V. Dietrich, C. Brune, A. Ishikawa, T. Sachse, C, gonczy, P. Cartwheel Architecture of Trichonympha Basal Body. López-García, Purificación, Tai, Vera, James, Erick R. Perlman, Steve J. Keeling, gut Contents of Termite - Nikon 2015 Small World Video Competition
Trichonympha
–
Trichonympha
40.
Human nutrition
–
Human nutrition refers to the provision of essential nutrients necessary to support human life and health. Generally, people can survive up to 40 days without food, poor nutrition is a chronic problem often linked to poverty, poor nutrition understanding and practices, and deficient sanitation and food security. Malnutrition and its consequences are immense contributors to deaths and disabilities worldwide, promoting good nutrition helps children grow, promotes human development and eradication of poverty. The human body contains chemical compounds, such as water, carbohydrates, amino acids, fatty acids and these compounds consist of elements such as carbon, hydrogen, oxygen, nitrogen, phosphorus, calcium, iron, zinc, magnesium, manganese, and so on. All the chemical compounds and elements contained in the body occur in various forms and combinations such as hormones, vitamins, phospholipids. These compounds may be found in the body as well as in the various types of organisms that humans consume. Comparing food to waste material can help determine the specific compounds, the effects of nutrients may only be discernible over an extended period of time, during which all food and waste must be analyzed. The number of involved in such experiments is high, making nutritional studies time-consuming and expensive. The seven major classes of nutrients are carbohydrates, fats, fiber, minerals, proteins, vitamins and these nutrient classes are categorized as either macronutrients or micronutrients. The macronutrients are carbohydrates, fats, fiber, proteins, the micronutrients are minerals and vitamins. The macronutrients provide structural material, and energy, some of the structural material can be used to generate energy internally, and in either case it is measured in Joules or kilocalories. Vitamins, minerals, fiber, and water do not provide energy, a third class of dietary material, fiber, seems also to be required, for both mechanical and biochemical reasons, though the exact reasons remain unclear. For all age groups, males need to consume higher amounts of macronutrients than females, in general, intakes increase with age until the second or third decade of life. Molecules of carbohydrates and fats consist of carbon, hydrogen, carbohydrates range from simple monosaccharides to complex polysaccharides. Fats are triglycerides, made of assorted fatty acid monomers bound to a glycerol backbone, some fatty acids, but not all, are essential in the diet, they cannot be synthesized in the body. Protein molecules contain nitrogen atoms in addition to carbon, oxygen, the fundamental components of protein are nitrogen-containing amino acids, some of which are essential in the sense that humans cannot make them internally. Some of the acids are convertible to glucose and can be used for energy production just as ordinary glucose. By breaking down existing protein, some glucose can be produced internally and this occurs naturally when atrophy takes place, or during periods of starvation
Human nutrition
–
Grain products: rich sources of complex and simple carbohydrates
Human nutrition
–
Protein milkshakes, made from protein powder (center) and milk (left), are a common
bodybuilding supplement.
41.
Insoluble
–
Solubility is the property of a solid, liquid, or gaseous chemical substance called solute to dissolve in a solid, liquid, or gaseous solvent. The solubility of a substance depends on the physical and chemical properties of the solute and solvent as well as on temperature, pressure. The solubility of a substance is a different property from the rate of solution. Most often, the solvent is a liquid, which can be a substance or a mixture. One may also speak of solid solution, but rarely of solution in a gas, the extent of solubility ranges widely, from infinitely soluble such as ethanol in water, to poorly soluble, such as silver chloride in water. The term insoluble is often applied to poorly or very poorly soluble compounds, a common threshold to describe something as insoluble is less than 0.1 g per 100 mL of solvent. Under certain conditions, the solubility can be exceeded to give a so-called supersaturated solution. Metastability of crystals can also lead to apparent differences in the amount of a chemical that dissolves depending on its form or particle size. A supersaturated solution generally crystallises when seed crystals are introduced and rapid equilibration occurs, phenylsalicylate is one such simple observable substance when fully melted and then cooled below its fusion point. Solubility is not to be confused with the ability to dissolve a substance, for example, zinc dissolves in hydrochloric acid as a result of a chemical reaction releasing hydrogen gas in a displacement reaction. The zinc ions are soluble in the acid, the smaller a particle is, the faster it dissolves although there are many factors to add to this generalization. Crucially solubility applies to all areas of chemistry, geochemistry, inorganic, physical, organic, in all cases it will depend on the physical conditions and the enthalpy and entropy directly relating to the solvents and solutes concerned. By far the most common solvent in chemistry is water which is a solvent for most ionic compounds as well as a range of organic substances. This is a factor in acidity/alkalinity and much environmental and geochemical work. According to the IUPAC definition, solubility is the composition of a saturated solution expressed as a proportion of a designated solute in a designated solvent. Solubility may be stated in units of concentration such as molarity, molality, mole fraction, mole ratio, mass per volume. Solubility occurs under dynamic equilibrium, which means that solubility results from the simultaneous and opposing processes of dissolution, the solubility equilibrium occurs when the two processes proceed at a constant rate. The term solubility is used in some fields where the solute is altered by solvolysis
Insoluble
–
Diving medicine:
Insoluble
–
"Soluble" redirects here. For the algebraic object called a "soluble group", see
Solvable group.
42.
Dietary fiber
–
Dietary fiber or roughage is the indigestible portion of food derived from plants. It has two components, Soluble fiber, which dissolves in water, is readily fermented in the colon into gases and physiologically active byproducts. It delays gastric emptying which in turn can cause a feeling of fullness. Insoluble fiber, which does not dissolve in water, is inert and provides bulking, or it can be prebiotic. Bulking fibers absorb water as they move through the digestive system, Dietary fibers can act by changing the nature of the contents of the gastrointestinal tract and by changing how other nutrients and chemicals are absorbed. Some types of soluble fiber absorb water to become a gelatinous, viscous substance which is fermented by bacteria in the digestive tract, some types of insoluble fiber have bulking action and are not fermented. Lignin, a major dietary insoluble fiber source, may alter the rate, other types of insoluble fiber, notably resistant starch, are fully fermented. A novel position has been adopted by the US Department of Agriculture to include functional fibers as isolated fiber sources that may be included in the diet, the term fiber is something of a misnomer, since many types of so-called dietary fiber are not actually fibrous. Food sources of fiber are often divided according to whether they provide soluble or insoluble fiber. Plant foods contain both types of fiber in varying degrees, according to the plants characteristics, a disadvantage of a diet high in fiber is the potential for significant intestinal gas production and bloating. Originally, fiber was defined to be the components of plants that resist human digestive enzymes, the definition was later changed to also include resistant starch, along with inulin and other oligosaccharides. Official definition of dietary fiber differs a little among different institutions, Dietary fibers are found in fruits, vegetables, the exact amount of fiber contained in the food can be seen in the following table of expected fiber in USDA food groups/subgroups Dietary fiber is found in plants. While all plants contain some fiber, plants with high concentrations are generally the most practical source. Fiber-rich plants can be eaten directly, or, alternatively, they can be used to make supplements and fiber-rich processed foods. The Academy of Nutrition and Dietetics, formerly the American Dietetic Association, some plants contain significant amounts of soluble and insoluble fiber. For example, plums and prunes have a thick skin covering a juicy pulp, the skin is a source of insoluble fiber, whereas soluble fiber is in the pulp. Grapes also contain an amount of fiber. The root of the plant, or glucomannan, produces results similar to fiber
Dietary fiber
–
Legumes contain healthy dietary fibers.
43.
Feces
–
Feces or faeces are the solid or semisolid metabolic waste from an animals digestive tract, discharged through the anus or cloaca during a process called defecation. Urine and feces together are called excreta, collected feces has various uses, namely as fertilizer or soil conditioner in agriculture, as a fuel source, or for medicinal purposes. After an animal has digested eaten material, the remains of material are discharged from its body as waste. Although it is lower in energy than the food from which it is derived, feces may retain a large amount of energy and this means that of all food eaten, a significant amount of energy remains for the decomposers of ecosystems. Many organisms feed on feces, from bacteria to fungi to insects such as dung beetles, some may specialize in feces, while others may eat other foods as well. Feces serve not only as a food, but also as a supplement to the usual diet of some animals. Feces and urine, which reflect light, are important to raptors such as kestrels. Seeds also may be found in feces, animals who eat fruit are known as frugivores. An advantage for a plant in having fruit is that animals will eat the fruit and this mode of seed dispersal is highly successful, as seeds dispersed around the base of a plant are unlikely to succeed and often are subject to heavy predation. Provided the seed can withstand the pathway through the system, it is not only likely to be far away from the parent plant. This cycling of matter is known as the biogeochemical cycle, the distinctive odor of feces is due to bacterial action. Gut flora produce compounds such as indole, skatole, and thiols and these are the same compounds that are responsible for the odor of flatulence. Consumption of foods prepared with spices may result in the spices being undigested, the perceived bad odor of feces has been hypothesized to be a deterrent for humans, as consuming or touching it may result in sickness or infection. Human perception of the odor may be contrasted by an animals perception of it, for example. In humans and depending on the individual and the circumstances, defecation may occur daily, extensive hardening of the feces may cause prolonged interruption in the routine and is called constipation. Human fecal matter varies significantly in appearance, depending on diet, normally it is semisolid, with a mucus coating. The brown coloration comes from a combination of bile and bilirubin, in newborn babies, initially fecal matter is yellow-green after the meconium. This coloration comes from the presence of bile alone, throughout the life of an ordinary human, one may experience many types of feces
Feces
–
A comparison of
elephant (left) and
human feces (right)
Feces
Feces
–
The
cassowary disperses plant seeds via its feces
Feces
–
Earthworm feces aid in provision of minerals and plant nutrients in an accessible form
44.
Defecation
–
Defecation is the final act of digestion, by which organisms eliminate solid, semisolid, or liquid waste material from the digestive tract via the anus. Humans expel feces with a frequency varying from a few times daily to a few times weekly, waves of muscular contraction in the walls of the colon move fecal matter through the digestive tract towards the rectum. Undigested food may also be expelled this way, in a process called egestion, as the waste fills the rectum and expands the rectal walls, nervous system stretch receptors in the rectal walls stimulate the desire to defecate. If defecation is delayed for a period the fecal matter may harden. If defecation occurs too fast, before liquid is absorbed. When the rectum is full, an increase in intra-rectal pressure forces apart the walls of the anal canal, the rectum shortens as material is forced into the anal canal and peristaltic waves push the feces out of the rectum. The internal and external anal sphincters along with the puborectalis muscle allow the feces to be passed by muscles pulling the anus up over the exiting feces, Defecation is normally assisted by taking a deep breath and trying to expel this air against a closed glottis. This contraction of expiratory chest muscles, diaphragm, abdominal wall muscles, ventilation at this point temporarily ceases as the lungs push the chest diaphragm down to exert the pressure. Thoracic blood pressure rises and as a response the amount of blood pumped by the heart decreases. Death has been known to occur in cases where defecation causes the pressure to rise enough to cause the rupture of an aneurysm or to dislodge blood clots. Also, in releasing the Valsalva maneuver blood pressure falls, this, coupled with standing up quickly to leave the toilet, during defecation, the external sphincter muscles relax. The anal and urethral sphincter muscles are closely linked, experiments by Harrison Weed at the Ohio State University Medical Center have shown they can only be contracted together, not individually, and that both show relaxation during urination. This explains why defecation is frequently accompanied by urination, Defecation may be involuntary or voluntary. Young children learn voluntary control through the process of toilet training, the anus and buttocks may be cleansed after defecation with toilet paper, similar paper products, or other absorbent material. In many cultures, such as Hindu and Muslim, water is used for cleansing after defecation. When water is used for cleansing after defecation, toilet paper may be used for drying the area afterwards. The positions and modalities of defecation are culture-dependent, squat toilets are used by the vast majority of the world, including most of Africa, Asia, and the Middle East. The use of sit-down toilets in the Western world is a recent development
Defecation
–
The
caganer is a defecating figurine in Spanish Nativity scenes
Defecation
–
Anatomy of the anus and rectum
45.
Anselme Payen
–
Anselme Payen was a French chemist known for discovering the enzyme diastase, and the carbohydrate cellulose. He began studying science with his father when he was 13-year-old, at the age of 23, Payen became manager of a borax-refining factory, where he developed a process for synthesizing borax from soda and boric acid. Previously, all borax had been imported from the East Indies exclusively by the Dutch, payens new method of synthesizing borax allowed him to sell the mineral at one third the going price, and break the Dutch monopoly. Payen also developed processes for refining sugar, along with a way to refine starch and alcohol from potatoes, Payen invented a decolorimeter, which dealt with the analysis, decolorization, bleaching, and crystallization of sugar. Payen discovered the first enzyme, diastase, in 1833 and he is also known for isolating and naming the carbohydrate cellulose. In 1835, Payen became a professor at École Centrale Paris and he was later elected professor at the Conservatoire National des Arts et Métiers. He died in Paris on May 13,1871, the American Chemical Societys Cellulose and Renewable Materials Division has established an annual award in his honor, the Anselme Payen Award
Anselme Payen
–
Anselme Payen
46.
Thermoplastic
–
A thermoplastic, or thermosoftening plastic, is a plastic material, a polymer, that becomes pliable or moldable above a specific temperature and solidifies upon cooling. Most thermoplastics have a molecular weight. The polymer chains associate through intermolecular forces, which weaken rapidly with increased temperature, thermoplastics differ from thermosetting polymers, which form irreversible chemical bonds during the curing process. Thermosets do not melt, but decompose and do not reform upon cooling, above its glass transition temperature and below its melting point, the physical properties of a thermoplastic change drastically without an associated phase change. Some thermoplastics do not fully crystallize below the transition temperature. Amorphous and semi-amorphous plastics are used when high optical clarity is necessary, amorphous and semi-amorphous plastics are less resistant to chemical attack and environmental stress cracking because they lack a crystalline structure. Brittleness can be decreased with the addition of plasticizers, which increases the mobility of amorphous chain segments to effectively lowers the transition temperature. Modification of the polymer through copolymerization or through the addition of side chains to monomers before polymerization can also lower it. Naval Research Laboratory developed thermoplastic armor, that can be repaired in the field by a user via tools for pressing irons, acrylic, a polymer called poly, is also known by trade names such as Lucite, Perspex and Plexiglas. It serves as a substitute for glass for items such as aquariums, motorcycle helmet visors, aircraft windows, viewing ports of submersibles. It is extensively used to make signs, including lettering and logos, in medicine, it is used in bone cement and to replace eye lenses. Acrylic paint consists of PMMA particles suspended in water, acrylonitrile butadiene styrene is a terpolymer synthesized from styrene and acrylonitrile in the presence of polybutadiene. ABS is a material that exhibits high impact resistance and mechanical toughness. It poses few risks to health under normal handling. It is used in consumer products, such as toys, appliances. Nylon belongs to a class of polymers called polyamides and it has served as a substitute mainly for hemp, cotton and silk, in products such as parachutes, cords, sails, flak vests and womens clothing. Nylon fibers are useful in making fabrics, rope, carpets and musical strings, whereas in bulk form, Nylon is used for mechanical parts including machine screws, gears, in addition, it is used in the manufacture of heat-resistant composite materials. Polylactic acid is a biodegradable thermoplastic aliphatic polyester derived from renewable resources, such as starch, tapioca roots, chips or starch
Thermoplastic
–
Stress Strain graph of thermoplastic material
47.
Celluloid
–
Celluloids are a class of compounds created from nitrocellulose and camphor, with added dyes and other agents. Generally considered the first thermoplastic, it was first created as Parkesine in 1856 and as Xylonite in 1869, Celluloid is easily molded and shaped, and it was first widely used as an ivory replacement. The main use was in movie and photography industries, which used only celluloid films prior to acetate films that were introduced in the 1950s. Celluloid is highly flammable, difficult and expensive to produce and no longer used, although its most common uses today are in table tennis balls, musical instruments. Collodion, invented in 1848 and used as a wound dressing, Parkes patented his discovery after realising a solid residue remained after evaporation of the solvent from photographic collodion. Parkes patented it as a clothing waterproofer for woven fabrics in the same year, later Parkes showcased Parkesine at the 1862 International Exhibition in London, where he was awarded a bronze medal for his efforts. The introduction of Parkesine is generally regarded as the birth of the plastics industry and he used cloth, ivory dust, and shellac, and on April 6,1869, patented a method of covering billiard balls with the addition of collodion. With assistance from Peter Kinnear and other investors, Hyatt formed the Albany Billiard Ball Company in Albany, New York, in 1870, John and his brother Isaiah patented a process of making a horn-like material with the inclusion of cellulose nitrate and camphor. Isaiah Hyatt dubbed his material celluloid in 1872, english inventor Daniel Spill had worked with Parkes and formed the Xylonite Co. to take over Parkes patents, describing the new plastic products as Xylonite. He took exception to the Hyatts claims and pursued the brothers in a number of cases between 1877 and 1884. The judge ruled all manufacturing of celluloid could continue both in Spills British Xylonite Company and Hyatts Celluloid Manufacturing Company, Hyatt used heat and pressure to simplify the manufacture of these compounds. Over the years, celluloid has become the term used for this type of plastic. English photographer John Carbutt founded the Keystone Dry Plate Works in 1879 with the intention of producing gelatin dry plates, the Celluloid Manufacturing Company was contracted for this work by means of thinly slicing layers out of celluloid blocks and then removing the slice marks with heated pressure plates. After this, the strips were coated with a photosensitive gelatin emulsion. It is not certain exactly how long it took for Carbutt to standardize his process, a 15-inch-wide sheet of Carbutts film was used by William Dickson for the early Edison motion picture experiments on a cylinder drum Kinetograph. However, the film base produced by this means was still considered too stiff for the needs of motion picture photography. By 1889, more flexible celluloids for photographic film were developed and this ability to produce photographic images on a flexible material was a crucial step toward the advent of motion pictures. Most movie and photography films prior to the move to acetate films in the fifties were made of celluloid
Celluloid
–
9.5 mm motion picture film
Celluloid
–
Newark, New Jersey, industrial production complex of the Celluloid Company (c. 1890)
Celluloid
–
Celluloid and
sterling silver pen.
Celluloid
–
Celluloid doll
48.
Silk
–
Silk is a natural protein fiber, some forms of which can be woven into textiles. The protein fiber of silk is composed mainly of fibroin and is produced by insect larvae to form cocoons. The best-known silk is obtained from the cocoons of the larvae of the mulberry silkworm Bombyx mori reared in captivity, Silk is produced by several insects, but generally only the silk of moth caterpillars has been used for textile manufacturing. There has been research into other types of silk, which differ at the molecular level. Silk is mainly produced by the larvae of insects undergoing complete metamorphosis, Silk production also occurs in Hymenoptera, silverfish, mayflies, thrips, leafhoppers, beetles, lacewings, fleas, flies, and midges. Other types of arthropod produce silk, most notably various arachnids such as spiders, the word silk comes from Old English sioloc, from Greek σηρικός serikos, silken, ultimately from an Asian source. Several kinds of silk, which are produced by caterpillars other than the mulberry silkworm, have been known and used in China, South Asia. However, the scale of production was far smaller than for cultivated silks. Thus, the way to obtain silk suitable for spinning into textiles in areas where commercial silks are not cultivated was by tedious. Commercial silks originate from reared silkworm pupae, which are bred to produce a silk thread with no mineral on the surface. The pupae are killed by either dipping them in boiling water before the adult moths emerge or by piercing them with a needle. These factors all contribute to the ability of the cocoon to be unravelled as one continuous thread. Wild silks also tend to be difficult to dye than silk from the cultivated silkworm. Genetic modification of domesticated silkworms is used to facilitate the production of more types of silk. Silk fabric was first developed in ancient China, the earliest example of silk fabric is from 3630 BC, and it was used as wrapping for the body of a child from a Yangshao culture site in Qingtaicun at Xingyang, Henan. Legend gives credit for developing silk to a Chinese empress, Leizu, because of its texture and lustre, silk rapidly became a popular luxury fabric in the many areas accessible to Chinese merchants. Silk was in demand, and became a staple of pre-industrial international trade. In July 2007, archaeologists discovered intricately woven and dyed silk textiles in a tomb in Jiangxi province, Silk is described in a chapter on mulberry planting by Si Shengzhi of the Western Han
Silk
–
Four of the most important domesticated silk moths. Top to bottom:
Bombyx mori,
Hyalophora cecropia,
Antheraea pernyi,
Samia cynthia. From
Meyers Konversations-Lexikon (1885–1892)
Silk
–
Woven silk textile from tomb no 1. at
Mawangdui in
Changsha,
Hunan province,
China, from the
Western Han Dynasty, 2nd century BC
Silk
–
A painting depicting women inspecting silk, early 12th century, ink and color on silk, by
Emperor Huizong of Song.
Silk
–
Portrait of a silk merchant in Guangzhou,
Qing dynasty, from
Peabody Essex Museum
49.
Hermann Staudinger
–
Hermann Staudinger was a German organic chemist who demonstrated the existence of macromolecules, which he characterized as polymers. For this work he received the 1953 Nobel Prize in Chemistry and he is also known for his discovery of ketenes and of the Staudinger reaction. Hermann Staudinger was born in 1881 in Worms, after receiving his Ph. D. from the University of Halle in 1903, Staudinger took a position at the University of Strasbourg. It was here that he discovered the ketenes, a family of molecules characterized by the general depicted in Figure 1. Ketenes would prove an important intermediate for the production of yet-to-be-discovered antibiotics such as penicillin and amoxicillin. In 1907, Staudinger began an assistant professorship at the Technical University of Karlsruhe, here, he successfully isolated a number of useful organic compounds as more completely reviewed by Rolf Mülhaupt. In 1912, Staudinger took on a new position at the Swiss Federal Institute of Technology in Zurich, one of his earliest discoveries came in 1919, when he and colleague Meyer reported that azides react with triphenylphosphine to form phosphazide. This reaction – commonly referred to as the Staudinger reaction – produces a high phosphazide yield. While at Karlsruhe and later, Zurich, Staudinger began research in the chemistry of rubber, for very high molecular weights had been measured by the physical methods of Raoult. In other words, polymers are like chains of paper clips, at first the majority of Staudinger’s colleagues refused to accept the possibility that small molecules could link together covalently to form high-molecular weight compounds. As Mülhaupt aptly notes, this is due in part to the fact that molecular structure, in 1926 he was appointed lecturer of chemistry at the University of Freiburg at Freiburg in Breisgau, where he spent the rest of his career. In 1927, he married the Latvian botanist, Magda Voita (also shown as, further evidence to support his polymer hypothesis emerged in the 1930s. High molecular weights of polymers were confirmed by membrane osmometry, the X-ray diffraction studies of polymers by Herman Mark provided direct evidence for long chains of repeating molecular units. And the synthetic work led by Carothers demonstrated that such as nylon. His theory opened up the subject to development, and helped place polymer science on a sound basis. Staudinger’s groundbreaking elucidation of the nature of the high-molecular weight compounds he termed Makromoleküle paved the way for the birth of the field of polymer chemistry, Staudinger himself saw the potential for this science long before it was fully realized. e. Staudinger founded the first polymer chemistry journal in 1940, and in 1953 received the Nobel Prize in Chemistry for “his discoveries in the field of macromolecular chemistry. ”In 1999, heidegger and Nazism, denounced or demoted non-Nazis Polymer science Helmut Ringsdorf. Hermann Staudinger and the Future of Polymer Research Jubilees – Beloved Occasions for Cultural Piety, ogilvie, Marilyn Bailey, Harvey, Joy Dorothy
Hermann Staudinger
–
Hermann Staudinger
Hermann Staudinger
–
Figure 3. A chain of paper clips (above) is a good model for a polymer such as
polylactic acid (below). The polymer chain is composed of small pieces linked together in a head-to-tail fashion.
50.
Enzyme
–
Enzymes /ˈɛnzaɪmz/ are macromolecular biological catalysts. Enzymes accelerate, or catalyze, chemical reactions, the molecules at the beginning of the process upon which enzymes may act are called substrates and the enzyme converts these into different molecules, called products. Almost all metabolic processes in the cell need enzymes in order to occur at rates fast enough to sustain life, the set of enzymes made in a cell determines which metabolic pathways occur in that cell. The study of enzymes is called enzymology, enzymes are known to catalyze more than 5,000 biochemical reaction types. Most enzymes are proteins, although a few are catalytic RNA molecules, enzymes specificity comes from their unique three-dimensional structures. Like all catalysts, enzymes increase the rate of a reaction by lowering its activation energy, some enzymes can make their conversion of substrate to product occur many millions of times faster. An extreme example is orotidine 5-phosphate decarboxylase, which allows a reaction that would take millions of years to occur in milliseconds. Chemically, enzymes are like any catalyst and are not consumed in chemical reactions, enzymes differ from most other catalysts by being much more specific. Enzyme activity can be affected by other molecules, inhibitors are molecules that decrease enzyme activity, many drugs and poisons are enzyme inhibitors. An enzymes activity decreases markedly outside its optimal temperature and pH, some enzymes are used commercially, for example, in the synthesis of antibiotics. French chemist Anselme Payen was the first to discover an enzyme, diastase and he wrote that alcoholic fermentation is an act correlated with the life and organization of the yeast cells, not with the death or putrefaction of the cells. In 1877, German physiologist Wilhelm Kühne first used the term enzyme, the word enzyme was used later to refer to nonliving substances such as pepsin, and the word ferment was used to refer to chemical activity produced by living organisms. Eduard Buchner submitted his first paper on the study of yeast extracts in 1897, in a series of experiments at the University of Berlin, he found that sugar was fermented by yeast extracts even when there were no living yeast cells in the mixture. He named the enzyme that brought about the fermentation of sucrose zymase, in 1907, he received the Nobel Prize in Chemistry for his discovery of cell-free fermentation. Following Buchners example, enzymes are usually named according to the reaction they carry out, the biochemical identity of enzymes was still unknown in the early 1900s. Sumner showed that the enzyme urease was a protein and crystallized it. These three scientists were awarded the 1946 Nobel Prize in Chemistry, the discovery that enzymes could be crystallized eventually allowed their structures to be solved by x-ray crystallography. This high-resolution structure of lysozyme marked the beginning of the field of structural biology, an enzymes name is often derived from its substrate or the chemical reaction it catalyzes, with the word ending in -ase
Enzyme
–
Eduard Buchner
Enzyme
–
The enzyme
glucosidase converts sugar
maltose to two
glucose sugars. Active site residues in red, maltose substrate in black, and NAD cofactor in yellow. (
PDB: 1OBB )
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. PMID 27759105. doi:10.1038/srep35578. Retrieved 19 October 2016.
"Cellulose". Encyclopædia Britannica. 5 (11th ed.). 1911.
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