1.
Jmol
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Jmol is computer software for molecular modelling chemical structures in 3-dimensions. Jmol returns a 3D representation of a molecule that may be used as a teaching tool and it is written in the programming language Java, so it can run on the operating systems Windows, macOS, Linux, and Unix, if Java is installed. It is free and open-source software released under a GNU Lesser General Public License version 2.0, a standalone application and a software development kit exist that can be integrated into other Java applications, such as Bioclipse and Taverna. A popular feature is an applet that can be integrated into web pages to display molecules in a variety of ways, for example, molecules can be displayed as ball-and-stick models, space-filling models, ribbon diagrams, etc. Jmol supports a range of chemical file formats, including Protein Data Bank, Crystallographic Information File, MDL Molfile. There is also a JavaScript-only version, JSmol, that can be used on computers with no Java, the Jmol applet, among other abilities, offers an alternative to the Chime plug-in, which is no longer under active development. While Jmol has many features that Chime lacks, it does not claim to reproduce all Chime functions, most notably, Chime requires plug-in installation and Internet Explorer 6.0 or Firefox 2.0 on Microsoft Windows, or Netscape Communicator 4.8 on Mac OS9. Jmol requires Java installation and operates on a variety of platforms. For example, Jmol is fully functional in Mozilla Firefox, Internet Explorer, Opera, Google Chrome, fast and Scriptable Molecular Graphics in Web Browsers without Java3D
2.
ChEMBL
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ChEMBL or ChEMBLdb is a manually curated chemical database of bioactive molecules with drug-like properties. It is maintained by the European Bioinformatics Institute, of the European Molecular Biology Laboratory, based at the Wellcome Trust Genome Campus, Hinxton, the database, originally known as StARlite, was developed by a biotechnology company called Inpharmatica Ltd. later acquired by Galapagos NV. The data was acquired for EMBL in 2008 with an award from The Wellcome Trust, resulting in the creation of the ChEMBL chemogenomics group at EMBL-EBI, the ChEMBL database contains compound bioactivity data against drug targets. Bioactivity is reported in Ki, Kd, IC50, and EC50, data can be filtered and analyzed to develop compound screening libraries for lead identification during drug discovery. ChEMBL version 2 was launched in January 2010, including 2.4 million bioassay measurements covering 622,824 compounds and this was obtained from curating over 34,000 publications across twelve medicinal chemistry journals. ChEMBLs coverage of available bioactivity data has grown to become the most comprehensive ever seen in a public database, in October 2010 ChEMBL version 8 was launched, with over 2.97 million bioassay measurements covering 636,269 compounds. ChEMBL_10 saw the addition of the PubChem confirmatory assays, in order to integrate data that is comparable to the type, ChEMBLdb can be accessed via a web interface or downloaded by File Transfer Protocol. It is formatted in a manner amenable to computerized data mining, ChEMBL is also integrated into other large-scale chemistry resources, including PubChem and the ChemSpider system of the Royal Society of Chemistry. In addition to the database, the ChEMBL group have developed tools and these include Kinase SARfari, an integrated chemogenomics workbench focussed on kinases. The system incorporates and links sequence, structure, compounds and screening data, the primary purpose of ChEMBL-NTD is to provide a freely accessible and permanent archive and distribution centre for deposited data. July 2012 saw the release of a new data service, sponsored by the Medicines for Malaria Venture. The data in this service includes compounds from the Malaria Box screening set, myChEMBL, the ChEMBL virtual machine, was released in October 2013 to allow users to access a complete and free, easy-to-install cheminformatics infrastructure. In December 2013, the operations of the SureChem patent informatics database were transferred to EMBL-EBI, in a portmanteau, SureChem was renamed SureChEMBL. 2014 saw the introduction of the new resource ADME SARfari - a tool for predicting and comparing cross-species ADME targets
3.
ChemSpider
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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
4.
European Chemicals Agency
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ECHA is the driving force among regulatory authorities in implementing the EUs chemicals legislation. ECHA helps companies to comply with the legislation, advances the safe use of chemicals, provides information on chemicals and it is located in Helsinki, Finland. The Agency, headed by Executive Director Geert Dancet, started working on 1 June 2007, the REACH Regulation requires companies to provide information on the hazards, risks and safe use of chemical substances that they manufacture or import. Companies register this information with ECHA and it is freely available on their website. So far, thousands of the most hazardous and the most commonly used substances have been registered, the information is technical but gives detail on the impact of each chemical on people and the environment. This also gives European consumers the right to ask whether the goods they buy contain dangerous substances. The Classification, Labelling and Packaging Regulation introduces a globally harmonised system for classifying and labelling chemicals into the EU. This worldwide system makes it easier for workers and consumers to know the effects of chemicals, companies need to notify ECHA of the classification and labelling of their chemicals. So far, ECHA has received over 5 million notifications for more than 100000 substances, the information is freely available on their website. Consumers can check chemicals in the products they use, Biocidal products include, for example, insect repellents and disinfectants used in hospitals. The Biocidal Products Regulation ensures that there is information about these products so that consumers can use them safely. ECHA is responsible for implementing the regulation, the law on Prior Informed Consent sets guidelines for the export and import of hazardous chemicals. Through this mechanism, countries due to hazardous chemicals are informed in advance and have the possibility of rejecting their import. Substances that may have effects on human health and the environment are identified as Substances of Very High Concern 1. These are mainly substances which cause cancer, mutation or are toxic to reproduction as well as substances which persist in the body or the environment, other substances considered as SVHCs include, for example, endocrine disrupting chemicals. Companies manufacturing or importing articles containing these substances in a concentration above 0 and they are required to inform users about the presence of the substance and therefore how to use it safely. Consumers have the right to ask the retailer whether these substances are present in the products they buy, once a substance has been officially identified in the EU as being of very high concern, it will be added to a list. This list is available on ECHA’s website and shows consumers and industry which chemicals are identified as SVHCs, Substances placed on the Candidate List can then move to another list
5.
E number
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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
6.
Simplified molecular-input line-entry system
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The simplified molecular-input line-entry system is a specification in form of a line notation for describing the structure of chemical species using short ASCII strings. SMILES strings can be imported by most molecule editors for conversion back into two-dimensional drawings or three-dimensional models of the molecules, the original SMILES specification was initiated in the 1980s. It has since modified and extended. In 2007, a standard called OpenSMILES was developed in the open-source chemistry community. Other linear notations include the Wiswesser Line Notation, ROSDAL and SLN, the original SMILES specification was initiated by David Weininger at the USEPA Mid-Continent Ecology Division Laboratory in Duluth in the 1980s. The Environmental Protection Agency funded the project to develop SMILES. It has since modified and extended by others, most notably by Daylight Chemical Information Systems. In 2007, a standard called OpenSMILES was developed by the Blue Obelisk open-source chemistry community. Other linear notations include the Wiswesser Line Notation, ROSDAL and SLN, in July 2006, the IUPAC introduced the InChI as a standard for formula representation. SMILES is generally considered to have the advantage of being slightly more human-readable than InChI, the term SMILES refers to a line notation for encoding molecular structures and specific instances should strictly be called SMILES strings. However, the term SMILES is also used to refer to both a single SMILES string and a number of SMILES strings, the exact meaning is usually apparent from the context. The terms canonical and isomeric can lead to confusion when applied to SMILES. The terms describe different attributes of SMILES strings and are not mutually exclusive, typically, a number of equally valid SMILES strings can be written for a molecule. For example, CCO, OCC and CC all specify the structure of ethanol, algorithms have been developed to generate the same SMILES string for a given molecule, of the many possible strings, these algorithms choose only one of them. This SMILES is unique for each structure, although dependent on the algorithm used to generate it. These algorithms first convert the SMILES to a representation of the molecular structure. A common application of canonical SMILES is indexing and ensuring uniqueness of molecules in a database, there is currently no systematic comparison across commercial software to test if such flaws exist in those packages. SMILES notation allows the specification of configuration at tetrahedral centers, and these are structural features that cannot be specified by connectivity alone and SMILES which encode this information are termed isomeric SMILES
7.
Chemical formula
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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
8.
Density
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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
9.
Melting point
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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
10.
Polymer
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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
11.
N-Vinylpyrrolidone
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N-Vinylpyrrolidone is an organic compound consisting of a 5-membered lactam linked to a vinyl group. It is a colorless liquid although samples can appear yellowish. It is produced industrially by reacting 2-pyrrolidone with acetylene and it is the precursor to polyvinylpyrrolidone, an important synthetic material. The NVP monomer is used as a reactive diluent in ultraviolet and electron-beam curable polymers applied as inks
12.
Blood plasma
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Blood plasma is a straw coloured liquid component of blood that normally holds the blood cells in whole blood in suspension, this makes plasma the extracellular matrix of blood cells. It makes up about 55% of the total blood volume. It is the fluid part of extracellular fluid. It is mostly water, and contains dissolved proteins, glucose, clotting factors, electrolytes, hormones, carbon dioxide, Plasma also serves as the protein reserve of the human body. It plays a role in an intravascular osmotic effect that keeps electrolytes in balanced form and protects the body from infection. Blood plasma is prepared by spinning a tube of fresh blood containing an anticoagulant in a centrifuge until the blood fall to the bottom of the tube. The blood plasma is then poured or drawn off, Blood plasma has a density of approximately 1025 kg/m3, or 1.025 g/ml. Blood serum is blood plasma without clotting factors, in other words, plasmapheresis is a medical therapy that involves blood plasma extraction, treatment, and reintegration. Fresh frozen plasma is on the WHO Model List of Essential Medicines, Blood plasma volume may be expanded by or drained to extravascular fluid when there are changes in Starling forces across capillary walls. For example, when blood pressure drops in circulatory shock, Starling forces drive fluid into the interstitium, standing still for a prolonged period will cause an increase in transcapillary hydrostatic pressure. As a result, approximately 12% of blood plasma volume will cross into the extravascular compartment and this causes an increase in hematocrit, serum total protein, blood viscosity and, as a result of increased concentration of coagulation factors, it causes orthostatic hypercoagulability. The use of plasma as a substitute for whole blood and for transfusion purposes was proposed in March 1918, in the correspondence columns of the British Medical Journal. Dried plasmas in powder or strips of material format were developed, prior to the United States involvement in the war, liquid plasma and whole blood were used. The Blood for Britain program during the early 1940s was quite successful based on Charles Drews contribution, a large project began in August 1940 to collect blood in New York City hospitals for the export of plasma to Britain. Drew was appointed supervisor of the Plasma for Britain project. His notable contribution at this time was to transform the test tube methods of many blood researchers into the first successful mass production techniques. Nonetheless, the decision was made to develop a dried plasma package for the forces as it would reduce breakage and make the transportation, packaging. The resulting dried plasma package came in two tin cans containing 400 cc bottles, one bottle contained enough distilled water to reconstitute the dried plasma contained within the other bottle
13.
Iodine
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Iodine is a chemical element with symbol I and atomic number 53. The heaviest of the halogens, it exists as a lustrous. The elemental form was discovered by the French chemist Bernard Courtois in 1811 and it was named two years later by Joseph-Louis Gay-Lussac from this property, after the Greek ἰωδης violet-coloured. Iodine occurs in many states, including iodide, iodate. It is the least abundant of the halogens, being the sixty-first most abundant element. It is even less abundant than the rare earths. It is the heaviest essential element, iodine is found in the thyroid hormones. Iodine deficiency affects two billion people and is the leading preventable cause of intellectual disabilities. The dominant producers of today are Chile and Japan. Iodine and its compounds are used in nutrition. Due to its atomic number and ease of attachment to organic compounds. Because of the specificity of its uptake by the human body, iodine is also used as a catalyst in the industrial production of acetic acid and some polymers. In 1811, iodine was discovered by French chemist Bernard Courtois, at that time of the Napoleonic Wars, saltpeter was in great demand in France. Saltpeter produced from French nitre beds required sodium carbonate, which could be isolated from seaweed collected on the coasts of Normandy, to isolate the sodium carbonate, seaweed was burned and the ash washed with water. The remaining waste was destroyed by adding sulfuric acid, Courtois once added excessive sulfuric acid and a cloud of purple vapour rose. He noted that the vapour crystallised on cold surfaces, making dark crystals, Courtois suspected that this material was a new element but lacked funding to pursue it further. Courtois gave samples to his friends, Charles Bernard Desormes and Nicolas Clément and he also gave some of the substance to chemist Joseph Louis Gay-Lussac, and to physicist André-Marie Ampère. On 29 November 1813, Desormes and Clément made Courtois discovery public and they described the substance to a meeting of the Imperial Institute of France
14.
Povidone-iodine
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Povidone-iodine, also known as iodopovidone, is an antiseptic used for skin disinfection before and after surgery. It may be used both to disinfect the skin of the patient and the hands of the healthcare providers and it may also be used for minor wounds. It may be applied to the skin as a liquid or a powder, if used on large wounds kidney problems, high blood sodium, and metabolic acidosis may occur. It is not recommended in people who are less than 32 weeks pregnant or taking lithium, frequent use is not recommended in people with thyroid problems. Povidone-iodine is a complex of povidone and the element iodine. It contains from 9% to 12% available iodine and it works by releasing iodine which results in the death of a range of microorganisms. Povidone-iodine came into use in 1955. It is on the World Health Organizations List of Essential Medicines, providone-iodine is available as a over the counter. The wholesale cost in the world is about 3.30 to 11.40 USD per liter of 10% solution. This amount in the United Kingdom cost the NHS about 10.86 pounds and it is sold under a number of brand names including Betadine. Povidone-iodine is a broad spectrum antiseptic for topical application in the treatment and it may be used in first aid for minor cuts, grazes, burns, abrasions and blisters. Povidone-iodine exhibits longer lasting antiseptic effects than tincture of iodine, due to its absorption via soft tissue. Chlorhexidine provides similar results, but with no toxicity concerns, bacteria do not develop resistance to PVP-I. For these purposes PVP-I has been formulated at concentrations of 7. 5–10. 0% in solution, spray, surgical scrub, ointment, and swab dosage forms. 2. 5% buffered PVP-I solution can be used for prevention of neonatal conjunctivitis, especially if it is caused by Neisseria gonorrhoeae and it is currently unclear whether PVP-I is more effective in reducing the incidence of conjunctivitis in neonates over other methods. PVP-I appears to be suitable for this purpose because, unlike other substances, it is also efficient against fungi. For this purpose, povidone-iodine is equally effective and safe as talc, PVP-I is contraindicated in patients with hyperthyroidism and other diseases of the thyroid, after treatment with radioiodine, and in patients with dermatitis herpetiformis. The sensitization rate to the product is 0. 7%, the iodine in PVP-I reacts with hydrogen peroxide, silver, taurolidine and proteins such as enzymes, rendering them ineffective
15.
Disinfectant
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Disinfectants are antimicrobial agents that are applied to the surface of non-living objects to destroy microorganisms that are living on the objects. Disinfectants are different from other agents such as antibiotics, which destroy microorganisms within the body, and antiseptics. Disinfectants are also different from biocides — the latter are intended to destroy all forms of life, Disinfectants work by destroying the cell wall of microbes or interfering with the metabolism. Sanitizer are substances that simultaneously clean and disinfect, Disinfectants are frequently used in hospitals, dental surgeries, kitchens, and bathrooms to kill infectious organisms. Bacterial endospores are most resistant to disinfectants, but some viruses, an alternative term used in the sanitation sector for disinfection of waste streams, sewage sludge or fecal sludge is sanitisation or sanitization. A perfect disinfectant would also complete and full microbiological sterilisation, without harming humans and useful form of life, be inexpensive. However, most disinfectants are also, by nature, potentially harmful to humans or animals, most modern household disinfectants contain Bitrex, an exceptionally bitter substance added to discourage ingestion, as a safety measure. Those that are used indoors should never be mixed with other cleaning products as chemical reactions can occur, the choice of disinfectant to be used depends on the particular situation. Some disinfectants have a spectrum, while others kill a smaller range of disease-causing organisms but are preferred for other properties. There are arguments for creating or maintaining conditions that are not conducive to survival and multiplication. Bacteria can increase in very quickly, which enables them to evolve rapidly. Should some bacteria survive an attack, they give rise to new generations composed completely of bacteria that have resistance to the particular chemical used. Under a sustained attack, the surviving bacteria in successive generations are increasingly resistant to the chemical used. For this reason, some question the wisdom of impregnating cloths, cutting boards, air disinfectants are typically chemical substances capable of disinfecting microorganisms suspended in the air. Disinfectants are generally assumed to be limited to use on surfaces, in 1928, a study found that airborne microorganisms could be killed using mists of dilute bleach. An air disinfectant must be dispersed either as an aerosol or vapour at a sufficient concentration in the air to cause the number of infectious microorganisms to be significantly reduced. In principle, these substances are ideal air disinfectants because they have both high lethality to microorganisms and low mammalian toxicity. The engineering challenge associated with creating a sufficient concentration of the glycol vapours in the air have not to date been sufficiently addressed, Alcohols are most effective when combined with distilled water to facilitate diffusion through the cell membrane, 100% alcohol typically denatures only external membrane proteins
16.
Topical medication
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A topical medication is a medication that is applied to a particular place on or in the body, as opposed to systemically. Most often this means application to surfaces such as the skin or mucous membranes to treat ailments via a large range of classes including creams, foams, gels, lotions. Many topical medications are epicutaneous, meaning that they are applied directly to the skin, as a route of administration, the topical route is contrasted with the enteral route, the intravenous route, and others. A topical effect, in the sense, may refer to a local, rather than systemic. However, many topically administered drugs have effects, because they reach the circulation after being absorbed by the tissues. Topical medications differ from other types of drugs because mishandling them can lead to certain complications in a patient or administrator of the drug. Some hydrophobic chemicals, such as hormones, can be absorbed into the body after being applied to the skin in the form of a cream, gel. Transdermal patches have become a means of administering some drugs for birth control, hormone replacement therapy. One example of an antibiotic that may be applied topically is chloramphenicol, a medications potency often is changed with its base. For example, some topical steroids will be classified one or two strengths higher when moving from cream to ointment, as a rule of thumb, an ointment base is more occlusive and will drive the medication into the skin more rapidly than a solution or cream base. The manufacturer of each product has total control over the content of the base of a medication. Although containing the active ingredients, one manufacturers cream might be more acidic than the next. For example, a formulation of miconazole antifungal cream might irritate the skin less than an athlete foot formulation of miconazole cream. These variations can, on occasion, result in different clinical outcomes, no comparative potency labeling exists to ensure equal efficacy between brands of topical steroids. Studies have confirmed that the potency of some topical steroid products may differ according to manufacturer or brand, however, in a simple base like an ointment, much less variation between manufacturers is common. In dermatology, the base of a medication is often as important as the medication itself. It is extremely important to receive a medication in the correct base, a pharmacist should not substitute an ointment for a cream, or vice versa, as the potency of the medication can change. As a result, what the manufacturers marketing department chooses to list on the label of a medication might be completely different from what the form would normally be called
17.
Pessary
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A pessary is a medical device inserted into the vagina, either to provide structural support, or as a method of delivering medication. A therapeutic pessary is a device similar to the outer ring of a diaphragm. Therapeutic pessaries are used to support the uterus, vagina, bladder, Pessaries are a treatment option for pelvic organ prolapse. A pessary is most commonly used to treat prolapse of the uterus and it is also used to treat stress urinary incontinence, a retroverted uterus, cystocele and rectocele. Historically, pessaries may have used to perform abortions. The Cerclage Pessary is used to treat pregnant women with cervical incompetence in order to support the cervix and it may be indicated in pregnancies with a history of premature labor, multiple pregnancies or mothers who are exposed to physical strain. It may also be indicated in pregnant women suffering from prolapse of the genital organs, the pessary can be placed temporarily or permanently, and must be fitted by a physician, physician assistant, midwife, or advanced practice nurse. Some pessaries can be worn during intercourse, Pessaries were used as birth control in ancient times. An occlusive pessary is generally used in combination with spermicide as a contraceptive, the stem pessary, a type of occlusive pessary, was an early form of the cervical cap. Shaped like a dome, it covered the cervix, and a rod or stem entered the uterus through the os. Side effects that are shared among most different types of pessaries are risks of increased vaginal discharge, vaginal irritation, ulceration, bleeding, one Package of Japanese Pessaries Suppository
18.
Talc
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Talc is a clay mineral composed of hydrated magnesium silicate with the chemical formula H2Mg34 or Mg3Si4O102. In loose form, it, along with starch, was one of the most widely used substances known as baby powder It occurs as foliated to fibrous masses. It has a perfect cleavage, and the folia are not elastic. Mohs scale of hardness, based on scratch hardness comparison. As such, talc can easily be scratched by a fingernail, talc has a specific gravity of 2. 5–2.8, a clear or dusty luster, and is translucent to opaque. Talc is not soluble in water, but is soluble in dilute mineral acids. Its color ranges from white to grey or green and it has a greasy feel. Soapstone is a rock composed predominantly of talc. The word talc derives from Medieval Latin talcus, which in turn originates from Arabic, طلق ṭalq which in turn was derived from Persian, in the ancient times, the word was used for various related minerals, including talc, mica, and selenite. Talc is a mineral that results from the metamorphism of magnesian minerals such as serpentine, pyroxene, amphibole. This is known as talc carbonation or steatization and produces a suite of known as talc carbonates. This is typically associated with high-pressure, low-temperature minerals such as phengite, garnet, such rocks are typically white, friable, and fibrous, and are known as whiteschist. Talc is a trioctahedral layered mineral, its structure is similar to pyrophyllite, talc is a common metamorphic mineral in metamorphic belts that contain ultramafic rocks, such as soapstone, and within whiteschist and blueschist metamorphic terranes. Talc carbonate ultramafics are typical of areas of the Archaean cratons. Talc-carbonate ultramafics are also known from the Lachlan Fold Belt, eastern Australia, from Brazil, the Guiana Shield, and from the belts of Turkey, Oman. Notable economic talc occurrences include the Mount Seabrook talc mine, Western Australia, the France-based Luzenac Group is the worlds largest supplier of mined talc. Its largest talc mine at Trimouns near Luzenac in southern France produces 400,000 tonnes of talc per year, talc is used in many industries, including paper making, plastic, paint and coatings, rubber, food, electric cable, pharmaceuticals, cosmetics, and ceramics. A coarse grayish-green high-talc rock is soapstone or steatite, used for stoves, sinks, electrical switchboards, crayons, soap and it is often used for surfaces of laboratory table tops and electrical switchboards because of its resistance to heat, electricity and acids
19.
Contact lens
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A contact lens, or simply contact, is a thin lens placed directly on the surface of the eye. Contact lenses are considered medical devices and can be worn to correct vision, in 2004, it was estimated that 125 million people use contact lenses worldwide, including 28 to 38 million in the United States. In 2010, worldwide market for contact lenses was estimated at $6.1 billion, multiple analysts estimated that the global market for contact lenses would reach $11.7 billion by 2015. As of 2010, the age of contact lens wearers globally was 31 years old. People choose to wear contact lenses for many reasons, aesthetics and cosmetics are the main motivating factors for people who want to avoid wearing glasses or to change the appearance of their eyes. Others wear contact lenses for functional or optical reasons, when compared with spectacles, contact lenses typically provide better peripheral vision, and do not collect moisture or perspiration, this makes them ideal for sports and other outdoor activities. Contact lens wearers can also wear sunglasses, goggles, or other eyewear of their choice without having to fit them with prescription lenses or worry about compatibility with glasses. Additionally, there are such as keratoconus and aniseikonia that are typically corrected better with contact lenses than with glasses. The size of the contact lens market is likely to due to the increasing occurrence of eye related conditions such as astigmatism. The other drivers are increasing population and the desire to make fashion statements, by the end of 2020, the value of the contact lens market is predicted to reach $13.5 billion. Neither idea was practically implementable in da Vincis time and he did not suggest his idea be used for correcting vision, as he was more interested in learning about the mechanisms of accommodation of the eye. Descartes proposed another idea in 1636, a tube filled with liquid placed in direct contact with the cornea. The protruding end was to be composed of glass, shaped to correct vision, however. In 1801, Thomas Young made a pair of contact lenses based on Descartes model. He used wax to affix water-filled lenses to his eyes, which neutralized its refractive power and he then corrected for it with another pair of lenses. However, like da Vincis, Youngs device was not intended to correct refraction errors and this enabled the manufacture of lenses that, for the first time, conformed to the actual shape of the eye. It was not until 1887 that German glassblower F. E. Muller produced the first eye covering to be seen through, in 1888, German ophthalmologist Adolf Gaston Eugen Fick constructed and fitted the first successful contact lens. These lenses were made from heavy blown glass and were 18–21 mm in diameter, Fick filled the empty space between cornea/callosity and glass with a dextrose solution
20.
Surfactant
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Surfactants are compounds that lower the surface tension between two liquids or between a liquid and a solid. Surfactants may act as detergents, wetting agents, emulsifiers, foaming agents, the term surfactant is a blend of surface active agent. In the United States National Library of Medicines Medical Subject Headings vocabulary, for the more general meaning, surface active agent/s is the heading. Surfactants are usually organic compounds that are amphiphilic, meaning they contain both hydrophobic groups and hydrophilic groups, therefore, a surfactant contains both a water-insoluble component and a water-soluble component. Surfactants will diffuse in water and adsorb at interfaces between air and water or at the interface between oil and water, in the case where water is mixed with oil. The water-insoluble hydrophobic group may extend out of the water phase, into the air or into the oil phase. World production of surfactants is estimated at 15 Mton/y, of which half are soaps. Other surfactants produced on a large scale are linear alkylbenzenesulfonates, lignin sulfonates, fatty alcohol ethoxylates. Other types of aggregates can also be formed, such as spherical or cylindrical micelles or lipid bilayers, the shape of the aggregates depends on the chemical structure of the surfactants, namely the balance in size between hydrophilic head and hydrophobic tail. A measure of this is the HLB, Hydrophilic-lipophilic balance, Surfactants reduce the surface tension of water by adsorbing at the liquid-air interface. The relation that links the surface tension and the excess is known as the Gibbs isotherm. The dynamics of adsorption depend on the coefficient of the surfactant. As the interface is created, the adsorption is limited by the diffusion of the surfactant to the interface, in some cases, there can exist an energetic barrier to adsorption or desorption of the surfactant. If such a barrier limits the rate, the dynamics are said to be ‘kinetically limited. Such energy barriers can be due to steric or electrostatic repulsions, the surface rheology of surfactant layers, including the elasticity and viscosity of the layer, play an important role in the stability of foams and emulsions. Interfacial and surface tension can be characterized by classical methods such as the -pendant or spinning drop method, surface rheology can be characterized by the oscillating drop method or shear surface rheometers such as double-cone, double-ring or magnetic rod shear surface rheometer. In solution, detergents help solubilize a variety of species by dissociating aggregates. Popular surfactants in the laboratory are SDS and CTAB
21.
Bausch & Lomb
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The company was founded in 1853 by an optician, John Jacob Bausch, and a financier, Henry Lomb. Its Ray-Ban brand of sunglasses was sold in 1999 to the Italian Luxottica Group, Bausch + Lomb was a public company listed on the NYSE until it was acquired by the private equity firm Warburg Pincus PLC in 2007. In May 2013, Valeant Pharmaceuticals agreed to buy Bausch + Lomb from Warburg Pincus LLC for $8.57 billion in cash. The deal, which was approved by share holders, included $4.2 billion earmarked to pay down Bausch + Lomb debt, today, the company is headquartered in Bridgewater, New Jersey, and employs about 13,000 people in 36 countries. Bausch + Lomb was founded in 1853 by John Jacob Bausch, Lomb both German immigrants, in Rochester, New York. A trained optician, Bausch found in Lomb the financier and partner he needed for a small, in 1861, the company manufactured Vulcanite rubber eyeglass frames and other precision vision products. During the American Civil War, the Union blockade caused the price of gold and this resulted in a growing demand for the Bausch & Lomb spectacles made from Vulcanite. In 1876, Ernst Gundlach joined the company and the company began manufacturing microscopes, later that year, the Bausch & Lomb Optical Company won a distinction at the Philadelphia Centennial Exposition. The company also produced photographic lenses, spectacle lenses, microtomes, binoculars, from 1892 in cooperation with Zeiss in Germany, the company produced optical lenses. In this manner, at the end of the 19th century, at the same time as this new expansion, a research department with five members was started to develop new products and improve old ones. A new alliance with the Zeiss company in Germany ensured competitive advantages for the three participants, Bausch & Lomb, Saegmuller and Zeiss, in terms of patent use and opening new markets. In 1902, William Bausch, the son of the founder, previously, the glass parts for the lenses had to be separated, ground and polished in a complicated process, and this brought significant savings in time and materials. The company produced the first optical-quality glass in America during the early to mid-1900s, by the year 1903 the company began manufacturing microscopes, binoculars, and camera shutters. The further development of the firm was affected by political events, until World War I, optical glass and the instruments made from it were often imported into most European and North American countries from Germany. The same was true of chemical products and laboratory equipment. The outbreak of the war, with Germanys new enemy status, in 1933, Bausch+Lomb started to honor outstanding high school science students with the Bausch+Lomb Honorary Science Award. In the 1930s, military products represented 70% of total production, the Ray-Ban brand of sunglasses was developed for pilots in 1936. After the Second World War, the photography and eyeglass sectors were strengthened and production in these sectors, in addition, production facilities were opened in Canada, Brazil and Argentina
22.
Glue stick
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Glue sticks are solid adhesives in twist or push-up tubes. The user can apply glue by holding the tube. Most glue sticks are designed to glue paper and card together and they can be used for craft and design, office use and at school. There are now permanent, washable, acid-free, non-toxic, solvent free, in 1969 the German company Henkel invented the glue stick after studying the twist-up ease and convenience of lipstick applicators. The product was released under the Pritt Stick brand, by 1971 the Pritt Stick was being sold in 38 countries, by 2001 in 121. The first solvent-free, multipurpose glue stick that could be used for materials was the PowerPritt. There is also a Pritt X, launched in 2010, glue sticks are made by many brands and each may have different features to it. Various brands, such as Scotch, UHU, Kores, Giotto, Snopake, generic brands also manufacture glue sticks, utilising the twist action. Glue sticks can come in sizes, the most common being 8g, 25g, 36g. Glue stick compositions are often proprietary, and vary by manufacturer, one style contains the following ingredients, The reportable composition of a Pritt Stick is as follows, Other brands are using e. g. polyvinylpyrrolidone as the glue substance
23.
Hot-melt adhesive
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The gun uses a continuous-duty heating element to melt the plastic glue, which the user pushes through the gun either with a mechanical trigger mechanism on the gun, or with direct finger pressure. The glue squeezed out of the nozzle is initially hot enough to burn. The glue is tacky when hot, and solidifies in a few seconds to one minute, hot melt adhesives can also be applied by dipping or spraying. In industrial use, hot melt adhesives provide several advantages over solvent-based adhesives, volatile organic compounds are reduced or eliminated, and the drying or curing step is eliminated. Hot melt adhesives have long life and usually can be disposed of without special precautions. This can be reduced by using an adhesive that after solidifying undergoes further curing e. g. by moisture. Some HMAs may not be resistant to attacks and weathering. HMAs do not lose thickness during solidifying, solvent-based adhesives may lose up to 50-70% of layer thickness during drying, melt viscosity, one of the most noticeable properties. Influences the spread of applied adhesive, and the wetting of the surfaces, melt flow index, a value roughly inversely proportional to the molecular weight of the base polymer. High melt flow index adhesives are easy to apply but have poor mechanical properties due to polymer chains. Low melt flow index adhesives have better properties but are difficult to apply. Pot life stability, the degree of stability in molten state, important for industrial processing where the adhesive is molten for prolonged periods before deposition. Surface energy, which influences wetting of different kind of surfaces, hot melt glues usually consist of one base material with various additives. The composition is formulated to have a glass transition temperature below the lowest service temperature. The degree of crystallization should be as high as possible but within limits of allowed shrinkage, the melt viscosity and the crystallization rate can be tailored for the application. Faster crystallization rate usually implies higher bond strength, some polymers can form hydrogen bonds between their chains, forming pseudo-cross-links which strengthen the polymer. The natures of the polymer and the used to increase tackiness influence the nature of mutual molecular interaction and interaction with the substrate. In one common system, EVA is used as the main polymer, polar groups, hydroxyls and amine groups can form acid-base and hydrogen bonds with polar groups on substrates like paper or wood or natural fibers
24.
Battery (electricity)
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An electric battery is a device consisting of one or more electrochemical cells with external connections provided to power electrical devices such as flashlights, smartphones, and electric cars. When a battery is supplying power, its positive terminal is the cathode. The terminal marked negative is the source of electrons that when connected to a circuit will flow. It is the movement of ions within the battery which allows current to flow out of the battery to perform work. Historically the term specifically referred to a device composed of multiple cells. Primary batteries are used once and discarded, the materials are irreversibly changed during discharge. Common examples are the battery used for flashlights and a multitude of portable electronic devices. Secondary batteries can be discharged and recharged multiple times using mains power from a wall socket, examples include the lead-acid batteries used in vehicles and lithium-ion batteries used for portable electronics such as laptops and smartphones. According to a 2005 estimate, the battery industry generates US$48 billion in sales each year. Batteries have much lower energy than common fuels such as gasoline. This is somewhat offset by the efficiency of electric motors in producing mechanical work. The usage of battery to describe a group of electrical devices dates to Benjamin Franklin, alessandro Volta built and described the first electrochemical battery, the voltaic pile, in 1800. This was a stack of copper and zinc plates, separated by brine-soaked paper disks, Volta did not understand that the voltage was due to chemical reactions. Although early batteries were of value for experimental purposes, in practice their voltages fluctuated. It consisted of a pot filled with a copper sulfate solution, in which was immersed an unglazed earthenware container filled with sulfuric acid. These wet cells used liquid electrolytes, which were prone to leakage and spillage if not handled correctly, many used glass jars to hold their components, which made them fragile and potentially dangerous. These characteristics made wet cells unsuitable for portable appliances, near the end of the nineteenth century, the invention of dry cell batteries, which replaced the liquid electrolyte with a paste, made portable electrical devices practical. Batteries convert chemical energy directly to electrical energy, a battery consists of some number of voltaic cells
25.
Ceramic
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A ceramic is an inorganic, non-metallic, solid material comprising metal, non-metal or metalloid atoms primarily held in ionic and covalent bonds. This article gives an overview of ceramic materials from the point of view of materials science, the crystallinity of ceramic materials ranges from highly oriented to semi-crystalline, vitrified, and often completely amorphous. Most often, fired ceramics are either vitrified or semi-vitrified as is the case with earthenware, stoneware, varying crystallinity and electron consumption in the ionic and covalent bonds cause most ceramic materials to be good thermal and electrical insulators. With such a range of possible options for the composition/structure of a ceramic, the breadth of the subject is vast. Many composites, such as fiberglass and carbon fiber, while containing ceramic materials, are not considered to be part of the ceramic family. The earliest ceramics made by humans were pottery objects or figurines made from clay, either by itself or mixed with materials like silica, hardened, sintered. Later ceramics were glazed and fired to create smooth, colored surfaces, decreasing porosity through the use of glassy, ceramics now include domestic, industrial and building products, as well as a wide range of ceramic art. In the 20th century, new materials were developed for use in advanced ceramic engineering. The word ceramic comes from the Greek word κεραμικός, of pottery or for pottery, from κέραμος, potters clay, tile, the earliest known mention of the root ceram- is the Mycenaean Greek ke-ra-me-we, workers of ceramics, written in Linear B syllabic script. The word ceramic may be used as an adjective to describe a material, product or process, or it may be used as a noun, either singular, or, more commonly, as the plural noun ceramics. A ceramic material is an inorganic, non-metallic, often crystalline oxide, nitride or carbide material, some elements, such as carbon or silicon, may be considered ceramics. Ceramic materials are brittle, hard, strong in compression, weak in shearing and they withstand chemical erosion that occurs in other materials subjected to acidic or caustic environments. Ceramics generally can withstand high temperatures, such as temperatures that range from 1,000 °C to 1,600 °C. Glass is often not considered a ceramic because of its amorphous character. However, glassmaking involves several steps of the process and its mechanical properties are similar to ceramic materials. Traditional ceramic raw materials include minerals such as kaolinite, whereas more recent materials include aluminium oxide. The modern ceramic materials, which are classified as advanced ceramics, include silicon carbide, both are valued for their abrasion resistance, and hence find use in applications such as the wear plates of crushing equipment in mining operations. Advanced ceramics are used in the medicine, electrical, electronics industries. Crystalline ceramic materials are not amenable to a range of processing
26.
Fiberglass
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Fiberglass is a type of fiber-reinforced plastic where the reinforcement fiber is specifically glass fiber. The glass fiber may be arranged, flattened into a sheet. The plastic matrix may be a polymer matrix – most often based on thermosetting polymers such as epoxy, polyester resin. The glass fibers are made of various types of glass depending upon the fiberglass use and these glasses all contain silica or silicate, with varying amounts of oxides of calcium, magnesium, and sometimes boron. To be used in fiberglass, glass fibers have to be made very low levels of defects. Fiberglass is a lightweight material and is used for many products. Although it is not as strong and stiff as composites based on fiber, it is less brittle. Its bulk strength and weight are also better than many metals, other common names for fiberglass are glass-reinforced plastic, glass-fiber reinforced plastic or GFK. Because glass fiber itself is referred to as fiberglass, the composite is also called fiberglass reinforced plastic. This article will adopt the convention that fiberglass refers to the glass fiber reinforced composite material. A patent for this method of producing glass wool was first applied for in 1933, Owens joined with the Corning company in 1935 and the method was adapted by Owens Corning to produce its patented fibreglas in 1936. Originally, fibreglas was a wool with fibers entrapping a great deal of gas, making it useful as an insulator. A suitable resin for combining the fibreglass with a plastic to produce a material was developed in 1936 by du Pont. The first ancestor of modern polyester resins is Cyanamids resin of 1942, peroxide curing systems were used by then. With the combination of fiberglass and resin the gas content of the material was replaced by plastic and this reduced the insulation properties to values typical of the plastic, but now for the first time the composite showed great strength and promise as a structural and building material. Confusingly, many glass fiber composites continued to be called fiberglass, ray Greene of Owens Corning is credited with producing the first composite boat in 1937, but did not proceed further at the time due to the brittle nature of the plastic used. In 1939 Russia was reported to have constructed a boat of plastic materials. The first car to have a body was a 1946 prototype of the Stout Scarab
27.
Inkjet printing
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Inkjet printing is a type of computer printing that recreates a digital image by propelling droplets of ink onto paper, plastic, or other substrates. Inkjet printers are the most commonly used type of printer, the concept of inkjet printing originated in the 20th century, and the technology was first extensively developed in the early 1950s. Starting in the late 1970s inkjet printers that could reproduce digital images generated by computers were developed, mainly by Epson, Hewlett-Packard, in the worldwide consumer market, four manufacturers account for the majority of inkjet printer sales, Canon, HP, Epson, and Brother. The emerging ink jet material deposition market also uses inkjet technologies, typically printheads using piezoelectric crystals, the technology has been extended and the ″ink″ can now also comprise living cells, for creating biosensors and for tissue engineering. There are two main technologies in use in contemporary inkjet printers, continuous and Drop-on-demand, the continuous inkjet method is used commercially for marking and coding of products and packages. In 1867 Lord Kelvin patented the syphon recorder, which recorded telegraph signals as a trace on paper using an ink jet nozzle deflected by a magnetic coil. The first commercial devices were introduced in 1951 by Siemens, the ink droplets are subjected to an electrostatic field created by a charging electrode as they form, the field varies according to the degree of drop deflection desired. This results in a controlled, variable electrostatic charge on each droplet, charged droplets are separated by one or more uncharged guard droplets to minimize electrostatic repulsion between neighbouring droplets. The more highly charged droplets are deflected to a greater degree, only a small fraction of the droplets is used to print, the majority being recycled. CIJ is one of the oldest ink jet technologies in use and is fairly mature, viscosity is monitored and a solvent is added to counteract solvent loss. Drop-on-demand is divided into thermal DOD and piezoelectric DOD, most consumer inkjet printers, including those from Canon, Hewlett-Packard, and Lexmark, use the thermal inkjet process. Vaughts work started in late 1978 with a project to develop fast, low-cost printing, the team at HP found that thin-film resistors could produce enough heat to fire an ink droplet. Two years later the HP and Canon teams found out about each others work, in the thermal inkjet process, the print cartridges consist of a series of tiny chambers, each containing a heater, all of which are constructed by photolithography. The inks involved are usually water-based and use either pigments or dyes as the colorant, the inks must have a volatile component to form the vapor bubble, otherwise droplet ejection cannot occur. As no special materials are required, the print head is generally cheaper to produce than in other inkjet technologies, most commercial and industrial inkjet printers and some consumer printers use a piezoelectric material in an ink-filled chamber behind each nozzle instead of a heating element. When a voltage is applied, the material changes shape, generating a pressure pulse in the fluid. A DOD process uses software that directs the heads to apply between zero and eight droplets of ink per dot, only where needed, piezo inkjet technology is often used on production lines to mark products. For instance, the date is often applied to products with this technique, in this application the head is stationary
28.
Inkjet paper
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Inkjet paper is a special fine paper designed for inkjet printers, typically classified by its weight, brightness and smoothness, and sometimes by its opacity. Some inkjet papers are made from high quality deinked pulp or chemical pulps, quality inkjet paper requires good dimensional stability, no curling or cockling, and good surface strength. For most purposes surface smoothness is required, sufficient and even porosity is required to counteract spreading of the ink. For lower quality printing, uncoated copy paper suffices, but higher grades require coating, the traditional coatings are not widely used for inkjet papers. For matte inkjet papers, it is common to use silica as pigment together with polyvinyl alcohol, Glossy inkjet papers can be made by multicoating, resin coating, or cast coating on a lamination paper. A variety of fine art inkjet papers meet the needs of professional photographers and these papers share many characteristics with traditional watercolor, printmaking, and photographic papers. Fine art inkjet papers are designed to meet standards for longevity as traditional fine art papers, they should have a neutral pH, be lignin-free. Fine art inkjet papers differ from traditional fine art papers, in that they include coatings engineered to receive, fine art papers are usually made of rag pulp but may also be have an alpha-cellulose base. Some descriptions and comparisons of fine art papers are here, here, here. Some fine art papers are made, while others are machine made. Many fine art papers are available in sheets or in rolls. Standard office paper has traditionally been designed for use with typewriters and copy machines, with these papers, moisture tends to wick through the fibers and away from the point of contact. For inkjet printing, this dulls edges of lines and graphic boundaries, high-quality inkjet printing with dark, crisp lines requires that the paper have exactly the right absorbency to accept the ink but prevent sideways spread. Many general-purpose office papers of weights around 21 to 27 lb have been reformulated to work well with both inkjet and laser printers. However, this category of paper is only suitable for printing text, Paper is manufactured by forming pulp fibers into a mat on an open mesh screen, and then drying and pressing this mat into paper. Double-sided inkjet printing is not possible with inexpensive low-weight copy paper because of bleed-through from one side to the other. These papers are also unsuitable for work because standard office paper is usually not white enough. This results in a color gamut and leads to muddy colors
29.
Chemical-mechanical planarization
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Chemical mechanical polishing/planarization is a process of smoothing surfaces with the combination of chemical and mechanical forces. It can be thought of as a hybrid of chemical etching, the process uses an abrasive and corrosive chemical slurry in conjunction with a polishing pad and retaining ring, typically of a greater diameter than the wafer. The pad and wafer are pressed together by a dynamic polishing head, the dynamic polishing head is rotated with different axes of rotation. This removes material and tends to even out any irregular topography and this may be necessary to set up the wafer for the formation of additional circuit elements. For example, CMP can bring the surface within the depth of field of a photolithography system. Typical depth-of-field requirements are down to Angstrom levels for the latest 22 nm technology, typical CMP tools, such as the ones seen on the right, consist of a rotating and extremely flat plate which is covered by a pad. The wafer that is being polished is mounted upside-down in a carrier/spindle on a backing film, the retaining ring keeps the wafer in the correct horizontal position. During the process of loading and unloading the wafer onto the tool, a slurry introduction mechanism deposits the slurry on the pad, represented by the slurry supply in Figure 1. Both the plate and the carrier are then rotated and the carrier is kept oscillating, a downward pressure/down force is applied to the carrier, pushing it against the pad, typically the down force is an average force, but local pressure is needed for the removal mechanisms. Down force depends on the area which, in turn, is dependent on the structures of both the wafer and the pad. Typically the pads have a roughness of 50 µm, contact is made by asperities and, as a result, in CMP, the mechanical properties of the wafer itself must be considered too. If the wafer has a slightly bowed structure, the pressure will be greater on the edges than it would on the center, in order to compensate for the wafer bow, pressure can be applied to the wafers backside which, in turn, will equalize the centre-edge differences. The pads used in the CMP tool should be rigid in order to polish the wafer surface. However, these pads must be kept in alignment with the wafer at all times. Therefore, real pads are often just stacks of soft and hard materials that conform to wafer topography to some extent. Generally, these pads are made from polymeric materials with a pore size between 30-50 µm, and because they are consumed in the process, they must be regularly reconditioned. In most cases the pads are very much proprietary, and are referred to by their trademark names rather than their chemical or other properties. Before about 1990 CMP was viewed as too dirty to be included in high-precision fabrication processes, since abrasion tends to create particles, since that time, the integrated circuit industry has moved from aluminium to copper conductors
30.
Emulsion
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An emulsion is a mixture of two or more liquids that are normally immiscible. Emulsions are part of a general class of two-phase systems of matter called colloids. Although the terms colloid and emulsion are sometimes used interchangeably, emulsion should be used when both phases, dispersed and continuous, are liquids, in an emulsion, one liquid is dispersed in the other. Examples of emulsions include vinaigrettes, homogenized milk, mayonnaise, the word emulsion comes from the Latin word for to milk, as milk is an emulsion of fat and water, along with other components. Two liquids can form different types of emulsions, as an example, oil and water can form, first, an oil-in-water emulsion, wherein the oil is the dispersed phase, and water is the dispersion medium. Second, they can form an emulsion, wherein water is the dispersed phase. Multiple emulsions are also possible, including a water-in-oil-in-water emulsion and an oil-in-water-in-oil emulsion, emulsions, being liquids, do not exhibit a static internal structure. The droplets dispersed in the matrix are usually assumed to be statistically distributed. The term emulsion is used to refer to the photo-sensitive side of photographic film. Such a photographic emulsion consist of silver halide colloidal particles dispersed in a gelatin matrix, nuclear emulsions are similar to photographic emulsions, except that they are used in particle physics to detect high-energy elementary particles. Emulsions contain both a dispersed and a phase, with the boundary between the phases called the interface. Emulsions tend to have an appearance because the many phase interfaces scatter light as it passes through the emulsion. Emulsions appear white when all light is scattered equally, if the emulsion is dilute enough, higher-frequency and low-wavelength light will be scattered more, and the emulsion will appear bluer – this is called the Tyndall effect. If the emulsion is concentrated enough, the color will be distorted toward comparatively longer wavelengths and this phenomenon is easily observable when comparing skimmed milk, which contains little fat, to cream, which contains a much higher concentration of milk fat. One example would be a mixture of water and oil, two special classes of emulsions – microemulsions and nanoemulsions, with droplet sizes below 100 nm – appear translucent. This property is due to the fact that lightwaves are scattered by the only if their sizes exceed about one-quarter of the wavelength of the incident light. Due to their similarity in appearance, translucent nanoemulsions and microemulsions are frequently confused, the required surfactant concentration in a microemulsion is, however, several times higher than that in a translucent nanoemulsion, and significantly exceeds the concentration of the dispersed phase. Because of many undesirable side-effects caused by surfactants, their presence is disadvantageous or prohibitive in many applications, in addition, the stability of a microemulsion is often easily compromised by dilution, by heating, or by changing pH levels
31.
Photoresist
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A positive resist is a type of photoresist in which the portion of the photoresist that is exposed to light becomes soluble to the photoresist developer. The unexposed portion of the photoresist remains insoluble to the photoresist developer, a negative photoresist is a type of photoresist in which the portion of the photoresist that is exposed to light becomes insoluble to the photoresist developer. The unexposed portion of the photoresist is dissolved by the photoresist developer, note, This table is based on generalizations which are generally accepted in the Microelectrionmechanical systems Fabrication industry. Based on the structure of photoresists, they can be classified into three types, Photopolymeric, photodecomposing, photocrosslinking photoresist. Photopolymeric photoresists are usually used for negative photoresist, e. g. methyl methacrylate, photodecomposing photoresist is a type of photoresist that generates hydrophilic productunder light. Photodecomposing photoresists are usually used for positive photoresist, a typical example is azide quinone, e. g. diazonaphthaquinone. Photocrosslinking photoresist is a type of photoresist, which could crosslink chain by chain when exposed to light, photocrosslinking photoresist are usually used for negative photoresist. SU-8 Off-Stoichiometry Thiol-Enes polymers For SAM photoresist, first an SAM is formed on the substrate by self-assembly, then, this surface covered by SAM is irradiated through a mask, similar to other photoresist, which generates a photo-patterned sample in the irradiated areas. And finally developer is used to remove the designed part, in lithography, decreasing the wavelength of light source is the most efficient way to achieve higher resolution. Photoresists are most commonly used at wavelengths in the spectrum or shorter. For example, diazonaphthoquinone absorbs strongly from approximately 300 nm to 450 nm, the absorption bands can be assigned to n-π* and π-π* transitions in the DNQ molecule. In the deep ultraviolet spectrum, the electronic transition in benzene or carbon double-bond chromophores appears at around 200 nm. Due to the appearance of more possible absorption transitions involving larger energy differences, photons with energies exceeding the ionization potential of the photoresist can also release electrons which are capable of additional exposure of the photoresist. From about 5 eV to about 20 eV, photoionization of outer valence electrons is the main absorption mechanism. Above 20 eV, inner electron ionization and Auger transitions become more important, photon absorption begins to decrease as the X-ray region is approached, as fewer Auger transitions between deep atomic levels are allowed for the higher photon energy. The absorbed energy can drive further reactions and ultimately dissipates as heat and this is associated with the outgassing and contamination from the photoresist. Photoresists can also be exposed by electron beams, producing the results as exposure by light. The main difference is that photons are absorbed, depositing all their energy at once, electrons deposit their energy gradually
32.
Cathode ray tube
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The cathode ray tube is a vacuum tube that contains one or more electron guns and a phosphorescent screen, and is used to display images. It modulates, accelerates, and deflects electron beam onto the screen to create the images, the images may represent electrical waveforms, pictures, radar targets, or others. CRTs have also used as memory devices, in which case the visible light emitted from the fluorescent material is not intended to have significant meaning to a visual observer. In television sets and computer monitors, the front area of the tube is scanned repetitively and systematically in a fixed pattern called a raster. An image is produced by controlling the intensity of each of the three beams, one for each additive primary color with a video signal as a reference. A CRT is constructed from an envelope which is large, deep, fairly heavy. The interior of a CRT is evacuated to approximately 0.01 Pa to 133 nPa. evacuation being necessary to facilitate the flight of electrons from the gun to the tubes face. That it is evacuated makes handling an intact CRT potentially dangerous due to the risk of breaking the tube and causing a violent implosion that can hurl shards of glass at great velocity. As a matter of safety, the face is made of thick lead glass so as to be highly shatter-resistant and to block most X-ray emissions. Flat panel displays can also be made in large sizes, whereas 38 to 40 was about the largest size of a CRT television, flat panels are available in 60. Cathode rays were discovered by Johann Hittorf in 1869 in primitive Crookes tubes and he observed that some unknown rays were emitted from the cathode which could cast shadows on the glowing wall of the tube, indicating the rays were traveling in straight lines. In 1890, Arthur Schuster demonstrated cathode rays could be deflected by electric fields, the earliest version of the CRT was known as the Braun tube, invented by the German physicist Ferdinand Braun in 1897. It was a diode, a modification of the Crookes tube with a phosphor-coated screen. In 1907, Russian scientist Boris Rosing used a CRT in the end of an experimental video signal to form a picture. He managed to display simple geometric shapes onto the screen, which marked the first time that CRT technology was used for what is now known as television. The first cathode ray tube to use a hot cathode was developed by John B. Johnson and Harry Weiner Weinhart of Western Electric and it was named by inventor Vladimir K. Zworykin in 1929. RCA was granted a trademark for the term in 1932, it released the term to the public domain in 1950. The first commercially made electronic television sets with cathode ray tubes were manufactured by Telefunken in Germany in 1934, in oscilloscope CRTs, electrostatic deflection is used, rather than the magnetic deflection commonly used with television and other large CRTs
33.
Metal
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A metal is a material that is typically hard, opaque, shiny, and has good electrical and thermal conductivity. Metals are generally malleable—that is, they can be hammered or pressed permanently out of shape without breaking or cracking—as well as fusible and ductile, about 91 of the 118 elements in the periodic table are metals, the others are nonmetals or metalloids. Some elements appear in both metallic and non-metallic forms, astrophysicists use the term metal to collectively describe all elements other than hydrogen and helium, the simplest two, in a star. The star fuses smaller atoms, mostly hydrogen and helium, to larger ones over its lifetime. In that sense, the metallicity of an object is the proportion of its matter made up of all chemical elements. Many elements and compounds that are not normally classified as metals become metallic under high pressures, the atoms of metallic substances are typically arranged in one of three common crystal structures, namely body-centered cubic, face-centered cubic, and hexagonal close-packed. In bcc, each atom is positioned at the center of a cube of eight others, in fcc and hcp, each atom is surrounded by twelve others, but the stacking of the layers differs. Some metals adopt different structures depending on the temperature, atoms of metals readily lose their outer shell electrons, resulting in a free flowing cloud of electrons within their otherwise solid arrangement. This provides the ability of metallic substances to easily transmit heat, while this flow of electrons occurs, the solid characteristic of the metal is produced by electrostatic interactions between each atom and the electron cloud. This type of bond is called a metallic bond, Metals are usually inclined to form cations through electron loss, reacting with oxygen in the air to form oxides over various timescales. Examples,4 Na + O2 →2 Na2O2 Ca + O2 →2 CaO4 Al +3 O2 →2 Al2O3, the transition metals are slower to oxidize because they form a passivating layer of oxide that protects the interior. Others, like palladium, platinum and gold, do not react with the atmosphere at all, some metals form a barrier layer of oxide on their surface which cannot be penetrated by further oxygen molecules and thus retain their shiny appearance and good conductivity for many decades. The oxides of metals are generally basic, as opposed to those of nonmetals, exceptions are largely oxides with very high oxidation states such as CrO3, Mn2O7, and OsO4, which have strictly acidic reactions. Painting, anodizing or plating metals are good ways to prevent their corrosion, however, a more reactive metal in the electrochemical series must be chosen for coating, especially when chipping of the coating is expected. Water and the two form an electrochemical cell, and if the coating is less reactive than the coatee. Metals in general have high conductivity, high thermal conductivity. Typically they are malleable and ductile, deforming under stress without cleaving, in terms of optical properties, metals are shiny and lustrous. Sheets of metal beyond a few micrometres in thickness appear opaque, although most metals have higher densities than most nonmetals, there is wide variation in their densities, lithium being the least dense solid element and osmium the densest
34.
Quenching
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In materials science, quenching is the rapid cooling of a workpiece to obtain certain material properties. A type of heat treating, quenching prevents undesired low-temperature processes, such as phase transformations, in steel alloyed with metals such as nickel and manganese, the eutectoid temperature becomes much lower, but the kinetic barriers to phase transformation remain the same. This allows quenching to start at a temperature, making the process much easier. High speed steel also has added tungsten, which serves to raise kinetic barriers, even cooling such alloys slowly in air has most of the desired effects of quenching. Extremely rapid cooling can prevent the formation of all crystal structure, if the percentage of carbon is less than 0.4 percent, quenching is not possible. Quench hardening is a process in which steel and cast iron alloys are strengthened and hardened. These metals consist of metals and alloys. This is done by heating the material to a certain temperature and this produces a harder material by either surface hardening or through-hardening varying on the rate at which the material is cooled. The material is often tempered to reduce the brittleness that may increase from the quench hardening process. Items that may be quenched include gears, shafts, and wear blocks, pearlite is not an ideal material for many common applications of steel alloys, as it is quite soft. Steels with this Martensitic structure are used in applications when the workpiece must be highly resistant to deformation. The process of quenching is a progression, beginning with heating the sample, most materials are heated to between 815 and 900 °C, with careful attention paid to keeping temperatures throughout the workpiece uniform. Minimizing uneven heating and overheating is key to imparting desired material properties, the second step in the quenching process is soaking. Workpieces can be soaked in air, a bath, or a vacuum. The recommended time allocation in salt or lead baths is up to 6 minutes, soaking times can range a little higher within a vacuum. As in the step, it is important that the temperature throughout the sample remains as uniform as possible during soaking. Once the workpiece has finished soaking, it moves on to the cooling step, during this step, the part is submerged into some kind of quenching fluid, different quenching fluids can have a significant effect on the final characteristics of a quenched part. Water is one of the most efficient quenching media where maximum hardness is desired, when hardness can be sacrificed, mineral oils are often used
35.
Membrane
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A membrane is a selective barrier, it allows some things to pass through but stops others. Such things may be molecules, ions, or other small particles, biological membranes include cell membranes, nuclear membranes, which cover a cell nucleus, and tissue membranes, such as mucosae and serosae. Synthetic membranes are made by humans for use in laboratories and industry and this concept of a membrane has been known since the eighteenth century, but was used little outside of the laboratory until the end of World War II. Drinking water supplies in Europe had been compromised by the war, however, due to the lack of reliability, slow operation, reduced selectivity and elevated costs, membranes were not widely exploited. The first use of membranes on a scale was with micro-filtration and ultra-filtration technologies. Since the 1980s, these processes, along with electrodialysis, are employed in large plants and, today. The degree of selectivity of a membrane depends on the pore size. Depending on the size, they can be classified as microfiltration, ultrafiltration, nanofiltration. Membranes can also be of various thickness, with homogeneous or heterogeneous structure, Membranes can be neutral or charged, and particle transport can be active or passive. The latter can be facilitated by pressure, concentration, chemical or electrical gradients of the membrane process, Membranes can be generally classified into synthetic membranes and biological membranes. Microfiltration removes particles higher than 0, 08-2 µm and operates within a range of 7-100 kPa, microfiltration is used to remove residual suspended solids, to remove bacteria in order to condition the water for effective disinfection and as a pre-treatment step for reverse osmosis. Relatively recent developments are membrane bioreactors which combine microfiltration and a bioreactor for biological treatment, ultrafiltration removes particles higher than 0, 005-2 µm and operates within a range of 70-700kPa. Ultrafiltration is used for many of the same applications as microfiltration, some ultrafiltration membranes have also been used to remove dissolved compounds with high molecular weight, such as proteins and carbohydrates. In addition, they are able to remove viruses and some endotoxins, nanofiltration is also known as “loose” RO and can reject particles smaller than 0,001 µm. Nanofiltration is used for the removal of selected dissolved constituents from wastewater, NF is primarily developed as a membrane softening process which offers an alternative to chemical softening. Likewise, nanofiltration can be used as a pre-treatment before directed reverse osmosis, the main objectives of NF pre-treatment are. Reverse osmosis is used for desalination. As well, RO is commonly used for the removal of dissolved constituents from wastewater remaining after advanced treatment with microfiltration, RO excludes ions but requires high pressures to produce deionized water
36.
Water purification
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Water purification is the process of removing undesirable chemicals, biological contaminants, suspended solids and gases from contaminated water. The goal is to produce water fit for a specific purpose, the standards for drinking water quality are typically set by governments or by international standards. These standards usually include minimum and maximum concentrations of contaminants, depending on the purpose of water use. Visual inspection cannot determine if water is of appropriate quality, simple procedures such as boiling or the use of a household activated carbon filter are not sufficient for treating all the possible contaminants that may be present in water from an unknown source. Even natural spring water – considered safe for all purposes in the 19th century – must now be tested before determining what kind of treatment. Chemical and microbiological analysis, while expensive, are the way to obtain the information necessary for deciding on the appropriate method of purification. The WHO estimates that 94% of these cases are preventable through modifications to the environment. Simple techniques for treating water at home, such as chlorination, filters, and solar disinfection, reducing deaths from waterborne diseases is a major public health goal in developing countries. Groundwater, The water emerging from deep ground water may have fallen as rain many tens, hundreds. Such water may emerge as springs, artesian springs, or may be extracted from boreholes or wells, deep ground water is generally of very high bacteriological quality, but the water may be rich in dissolved solids, especially carbonates and sulfates of calcium and magnesium. Depending on the strata through which the water has flowed, other ions may also be present including chloride, there may be a requirement to reduce the iron or manganese content of this water to make it acceptable for drinking, cooking, and laundry use. Primary disinfection may also be required, where groundwater recharge is practised, the groundwater may require additional treatment depending on applicable state and federal regulations. Bacteria and pathogen levels are low, but some bacteria. Where uplands are forested or peaty, humic acids can colour the water, many upland sources have low pH which require adjustment. Rivers, canals and low land reservoirs, Low land surface waters will have a significant bacterial load and may also contain algae, suspended solids and a variety of dissolved constituents. Atmospheric water generation is a new technology that can provide high quality drinking water by extracting water from the air by cooling the air, desalination of seawater by distillation or reverse osmosis. Surface Water, Freshwater bodies that are open to the atmosphere and are not designated as groundwater are termed surface waters. The aims of the treatment are to remove unwanted constituents in the water, the choice of method will depend on the quality of the water being treated, the cost of the treatment process and the quality standards expected of the processed water
37.
Crop
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A crop is any cultivated plant, fungus, or alga that is harvested for food, clothing, livestock, fodder, biofuel, medicine, or other uses. In contrast, animals that are raised by humans are called livestock, microbes, such as bacteria or viruses, are referred to as cultures. Microbes are not typically grown for food, but are used to alter food. For example, bacteria are used to ferment milk to produce yogurt, major crops include sugarcane, pumpkin, maize, wheat, rice, cassava, soybeans, hay, potatoes, and cotton. Sleper, David A. Poehlman, John M. Breeding Field Crops
38.
Coating
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A coating is a covering that is applied to the surface of an object, usually referred to as the substrate. The purpose of applying the coating may be decorative, functional, the coating itself may be an all-over coating, completely covering the substrate, or it may only cover parts of the substrate. Functional coatings may be applied to change the properties of the substrate, such as adhesion, wetability, corrosion resistance. A further consideration for non-all-over coatings is that control is needed as to where the coating is to be applied, a number of these non-all-over coating processes are printing processes. Many industrial coating processes involve the application of a film of functional material to a substrate, such as paper, fabric, film, foil. If the substrate starts and ends the process wound up in a roll, a roll of substrate, when wound through the coating machine, is typically called a web. Coatings may be applied as liquids, gases or solids, metal coatings on plastic airframes Conductive coatings e. g. to manufacture some types of resistors Insulating coatings e. g. This method commonly implies slot-die coating above room temperature, but it also is possible to have hot-melt roller coating, hot-melt metering-rod coating, curtain coating- low viscosity, with the slot vertically above the web and a gap between slotdie and web. Slide coating- bead coating with a slide between the slotdie and the bead. Very successfully used for multilayer coating in the photographic industry, slot die bead coating- typically with the web backed by a roller and a very small gap between slotdie and web. Tensioned-web slotdie coating- with no backing for the web, inkjet printing Lithography Flexography Spin coating Dip coating Titanium and titanium alloys, edited by C. Leyens and M. Peters, Wiley-VCH, ISBN 3-527-30534-3, table 6, licari, William Andrew Publishing, Elsevier, ISBN 0-8155-1492-1 High-Performance Organic Coatings, ed. AS Khanna, Elsevier BV,2015, ISBN 978-1-84569-265-0
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