A wash bottle is a squeeze bottle with a nozzle, used to rinse various pieces of laboratory glassware, such as test tubes and round bottom flasks. Wash bottles are sealed with a screw-top lid; when hand pressure is applied to the bottle, the liquid inside becomes pressurized and is forced out of the nozzle into a narrow stream of liquid. Most wash bottles are made up of polyethylene, a flexible solvent-resistant petroleum-based plastic. Most bottles contain an internal dip tube allowing upright use. Wash bottles may be filled with a range of common laboratory solvents and reagents, according to the work to be undertaken; these include deionized water, detergent solutions and rinse solvents such as acetone, isopropanol or ethanol. In biological labs it is common to keep sodium hypochlorite solution in a wash bottle to disinfect unneeded cultures. There are a consistent set of colour codes and markings used to identify the contents of wash bottles. Red is used for acetone, White for ethanol or sodium hypochlorite, green for Methanol is yellow for isopropanol and blue for distilled water.
Safety warning labels are used to identify potential hazards. Where reagents with high vapour pressure are used such as ethanol or methanol, small pressure release holes are incorporated into the cap to release and excess vapour pressure and avoid material being ejected through the nozzle when not in use; the use of wash bottles helps rusers measure the precise amount of liquid used. In addition, unwanted substances or particles cannot pass through wash bottles; the use of wash bottles is more convenient than using graduated cylinders. Wash bottles are kept on the laboratory bench in a secure way so that they can be located and so that they do not interfere with other work taking place; such containment may be by the use of two ring clamps which have similar size attached to a lattice rod. Different types of wash bottles are suitable with different types of substances. A spiral gas-lift wash bottle, for example, is suitable for eliminating gas with the liquid system having two phases like bromide and water.
In addition, a Simple graduated. A type of strong solvent and a type of destructive substance can be dealt with Nalgene Teflon FEP wash bottles since the special type of plastic is used to produce this type of wash bottles. Squeeze bottle
A static mixer is a precision engineered device for the continuous mixing of fluid materials, without moving components. The fluids to be mixed are liquid, but static mixers can be used to mix gas streams, disperse gas into liquid or blend immiscible liquids; the energy needed for mixing comes from a loss in pressure. One design of static mixer is the plate-type mixer and another common device type consists of mixer elements contained in a cylindrical or squared housing. Mixer size can vary from about 6 mm to 6 meters diameter. Typical construction materials for static mixer components included stainless steel, Teflon, PVDF, PVC, CPVC and polyacetal; the latest design involve static mixing elements made of glass-lined steel. In the plate type design mixing is accomplished through intense turbulence in the flow. In the housed-elements design the static mixer elements consist of a series of baffles made of metal or a variety of plastics; the mixer housing can be made of metal or plastic. The housed-elements design incorporates a method for delivering two streams of fluids into the static mixer.
As the streams move through the mixer, the non-moving elements continuously blend the materials. Complete mixing depends on many variables including the fluids' properties, tube inner diameter, number of elements and their design; the housed-elements mixer's fixed helical elements can produce patterns of flow division and radial mixing: Flow division: In laminar flow, a processed material divides at the leading edge of each element of the mixer and follows the channels created by the element shape. At each succeeding element, the two channels are further divided, resulting in an exponential increase in stratification; the number of striations produced is 2n. Radial mixing: In either turbulent flow or laminar flow, rotational circulation of a processed material around its own hydraulic center in each channel of the mixer causes radial mixing of the material. Processed material is intermixed to reduce or eliminate radial gradients in temperature and material composition. A common application is mixing nozzles for two-component sealants.
Other applications include chemical processing. Static mixers can be used in the refinery and oil and gas markets as well, for example in bitumen processing or for desalting crude oil. In polymer production, static mixers can be used to facilitate polymerization reactions or for the admixing of liquid additives; the static mixer traces its origins to an invention for a mixing device filed on Nov. 29, 1965 by the Arthur D. Little Company; this device was the housed-elements type and was licensed to the Kenics Corporation and marketed as the Kenics Motionless Mixer. Today, the Kenics brand is owned by National Oilwell Varco; the plate type static mixer patent was issued on November 24, 1998 to Robert W. Glanville of Westfall Manufacturing. Thermal cleaning Static Mixer
Ultraviolet designates a band of the electromagnetic spectrum with wavelength from 10 nm to 400 nm, shorter than that of visible light but longer than X-rays. UV radiation is present in sunlight, contributes about 10% of the total light output of the Sun, it is produced by electric arcs and specialized lights, such as mercury-vapor lamps, tanning lamps, black lights. Although long-wavelength ultraviolet is not considered an ionizing radiation because its photons lack the energy to ionize atoms, it can cause chemical reactions and causes many substances to glow or fluoresce; the chemical and biological effects of UV are greater than simple heating effects, many practical applications of UV radiation derive from its interactions with organic molecules. Suntan and sunburn are familiar effects of over-exposure of the skin to UV, along with higher risk of skin cancer. Living things on dry land would be damaged by ultraviolet radiation from the Sun if most of it were not filtered out by the Earth's atmosphere.
More energetic, shorter-wavelength "extreme" UV below 121 nm ionizes air so that it is absorbed before it reaches the ground. Ultraviolet is responsible for the formation of bone-strengthening vitamin D in most land vertebrates, including humans; the UV spectrum thus has effects both harmful to human health. The lower wavelength limit of human vision is conventionally taken as 400 nm, so ultraviolet rays are invisible to humans, although some people can perceive light at shorter wavelengths than this. Insects and some mammals can see near-UV. Ultraviolet rays are invisible to most humans; the lens of the human eye blocks most radiation in the wavelength range of 300–400 nm. Humans lack color receptor adaptations for ultraviolet rays; the photoreceptors of the retina are sensitive to near-UV, people lacking a lens perceive near-UV as whitish-blue or whitish-violet. Under some conditions and young adults can see ultraviolet down to wavelengths of about 310 nm. Near-UV radiation is visible to insects, some mammals, birds.
Small birds have a fourth color receptor for ultraviolet rays. "Ultraviolet" means "beyond violet", violet being the color of the highest frequencies of visible light. Ultraviolet has a higher frequency than violet light. UV radiation was discovered in 1801 when the German physicist Johann Wilhelm Ritter observed that invisible rays just beyond the violet end of the visible spectrum darkened silver chloride-soaked paper more than violet light itself, he called them "oxidizing rays" to emphasize chemical reactivity and to distinguish them from "heat rays", discovered the previous year at the other end of the visible spectrum. The simpler term "chemical rays" was adopted soon afterwards, remained popular throughout the 19th century, although some said that this radiation was different from light; the terms "chemical rays" and "heat rays" were dropped in favor of ultraviolet and infrared radiation, respectively. In 1878 the sterilizing effect of short-wavelength light by killing bacteria was discovered.
By 1903 it was known. In 1960, the effect of ultraviolet radiation on DNA was established; the discovery of the ultraviolet radiation with wavelengths below 200 nm, named "vacuum ultraviolet" because it is absorbed by the oxygen in air, was made in 1893 by the German physicist Victor Schumann. The electromagnetic spectrum of ultraviolet radiation, defined most broadly as 10–400 nanometers, can be subdivided into a number of ranges recommended by the ISO standard ISO-21348: A variety of solid-state and vacuum devices have been explored for use in different parts of the UV spectrum. Many approaches seek to adapt visible light-sensing devices, but these can suffer from unwanted response to visible light and various instabilities. Ultraviolet can be detected by suitable photodiodes and photocathodes, which can be tailored to be sensitive to different parts of the UV spectrum. Sensitive ultraviolet photomultipliers are available. Spectrometers and radiometers are made for measurement of UV radiation.
Silicon detectors are used across the spectrum. Vacuum UV, or VUV, wavelengths are absorbed by molecular oxygen in the air, though the longer wavelengths of about 150–200 nm can propagate through nitrogen. Scientific instruments can therefore utilize this spectral range by operating in an oxygen-free atmosphere, without the need for costly vacuum chambers. Significant examples include 193 nm photolithography equipment and circular dichroism spectrometers. Technology for VUV instrumentation was driven by solar astronomy for many decades. While optics can be used to remove unwanted visible light that contaminates the VUV, in general, detectors can be limited by their response to non-VUV radiation, the development of "solar-blind" devices has been an important area of research. Wide-gap solid-state devices or vacuum devices with high-cutoff photocathodes can be attractive compared to silicon diodes. Extreme UV is characterized by a transition in the physics of interaction with matter. Wavelengths longer than about 30 nm interact with the outer valence electrons of atoms, while wavelengths shorter than that interact with inner-shell electrons and nuclei.
The long end of the EUV spectrum is set by a prominent He+ spectr
A laboratory is a facility that provides controlled conditions in which scientific or technological research and measurement may be performed. Laboratories used for scientific research take many forms because of the differing requirements of specialists in the various fields of science and engineering. A physics laboratory might contain a particle accelerator or vacuum chamber, while a metallurgy laboratory could have apparatus for casting or refining metals or for testing their strength. A chemist or biologist might use a wet laboratory, while a psychologist's laboratory might be a room with one-way mirrors and hidden cameras in which to observe behavior. In some laboratories, such as those used by computer scientists, computers are used for either simulations or the analysis of data. Scientists in other fields will use still other types of laboratories. Engineers use laboratories as well to design and test technological devices. Scientific laboratories can be found as research room and learning spaces in schools and universities, government, or military facilities, aboard ships and spacecraft.
Despite the underlying notion of the lab as a confined space for experts, the term "laboratory" is increasingly applied to workshop spaces such as Living Labs, Fab Labs, or Hackerspaces, in which people meet to work on societal problems or make prototypes, working collaboratively or sharing resources. This development is inspired by new, participatory approaches to science and innovation and relies on user-centred design methods and concepts like Open innovation or User innovation. One distinctive feature of work in Open Labs is phenomena of translation, driven by the different backgrounds and levels of expertise of the people involved. Early instances of "laboratories" recorded in English involved alchemy and the preparation of medicines; the emergence of Big Science during World War II increased the size of laboratories and scientific equipment, introducing particle accelerators and similar devices. The earliest laboratory according to the present evidence is a home laboratory of Pythagoras of Samos, the well-known Greek philosopher and scientist.
This laboratory was created when Pythagoras conducted an experiment about tones of sound and vibration of string. In the painting of Louis Pasteur by Albert Edelfelt in 1885, Louis Pasteur is shown comparing a note in his left hand with a bottle filled with a solid in his right hand, not wearing any personal protective equipment. Researching in teams started in the 19th century, many new kinds of equipment were developed in the 20th century. A 16th century underground alchemical laboratory was accidentally discovered in the year 2002. Rudolf II, Holy Roman Emperor was believed to be the owner; the laboratory is preserved as a museum in Prague. Laboratory techniques are the set of procedures used on natural sciences such as chemistry, physics to conduct an experiment, all of them follow the scientific method. Laboratory equipment refers to the various tools and equipment used by scientists working in a laboratory: The classical equipment includes tools such as Bunsen burners and microscopes as well as specialty equipment such as operant conditioning chambers, spectrophotometers and calorimeters.
Chemical laboratorieslaboratory glassware such as the beaker or reagent bottle Analytical devices as HPLC or spectrophotometersMolecular biology laboratories + Life science laboratoriesAutoclave Microscope Centrifuges Shakers & mixers Pipette Thermal cyclers Photometer Refrigerators and Freezers Universal testing machine ULT Freezers Incubators Bioreactor Biological safety cabinets Sequencing instruments Fume hoods Environmental chamber Humidifier Weighing scale Reagents Pipettes tips Polymer consumables for small volumes sterileLaboratory equipment is used to either perform an experiment or to take measurements and gather data. Larger or more sophisticated equipment is called a scientific instrument; the title of laboratory is used for certain other facilities where the processes or equipment used are similar to those in scientific laboratories. These notably include: Film laboratory or Darkroom Clandestine lab for the production of illegal drugs Computer lab Crime lab used to process crime scene evidence Language laboratory Medical laboratory Public health laboratory Industrial laboratory In many laboratories, hazards are present.
Laboratory hazards might include poisons. Therefore, safety precautions are vitally important. Rules exist to minimize the individual's risk, safety equipment is used to protect the lab users from injury or to assist in responding to an emergency; the Occupational Safety and Health Administration in the United States, recognizing the unique characteristics of the laboratory workplace, has tailored a standard for occupational exposure to hazardous chemicals in laboratories. This standard is referred to as the "Laboratory Standard". Under this standard, a laboratory is required to produce a Chemical Hygiene Plan which addresses the specific hazards found in its location, its approach to them. In determining the proper Chemical Hygiene Plan for a particular business or laboratory, it is necessary to understand the requirements of the standard, evaluation of the current safety and environmental practi
Polythiophenes are polymerized thiophenes, a sulfur heterocycle. They are white solids with the formula n for the parent PT; the rings are linked through the 2- and 5-positions. Polys have substituents at the 3- or 4-position, they are white solids, but tend to be soluble in organic solvents. PTs become conductive; the electrical conductivity results from the delocalization of electrons along the polymer backbone. Conductivity however is not the only interesting property resulting from electron delocalization; the optical properties of these materials respond to environmental stimuli, with dramatic color shifts in response to changes in solvent, applied potential, binding to other molecules. Changes in both color and conductivity are induced by the same mechanism, twisting of the polymer backbone and disrupting conjugation, making conjugated polymers attractive as sensors that can provide a range of optical and electronic responses; the development of polythiophenes and related conductive organic polymers was recognized by the awarding of the 2000 Nobel Prize in Chemistry to Alan J. Heeger, Alan MacDiarmid, Hideki Shirakawa "for the discovery and development of conductive polymers".
PT is an ordinary organic polymer, being a white solid, poorly soluble in most solvents. Upon treatment with oxidizing agents, however the material takes on a dark color and becomes electrically conductive. Oxidation is referred to as "doping". Around 0.2 equivalent of oxidant is used to convert PTs into the optimmally conductive state. Thus about one of every five rings is oxidized. Many different oxidants are used; because of the redox reaction, the conductive form of polythiophene is a salt. An idealized stoichiometry is shown using the oxidant PF6: n + 1/5n PF6 → n0.2n + 1/5 nAIn principle, PT can be n-doped using reducing agents, but this approach is practiced. Upon "p-doping", charged unit called; the bipolaron moves as a unit along the polymer chain and is responsible for the macroscopically observed conductivity of the material. Conductivity can approach 1000 S/cm. In comparison, the conductivity of copper is 5×105 S/cm; the conductivity of PTs is lower than 1000 S/cm, but high conductivity is not necessary for many applications, e.g. as an antistatic film.
A variety of reagents have been used to dope PTs. Iodine and bromine produce conductive materials, which are unstable owing to slow evaporation of the halogen. Organic acids, including trifluoroacetic acid, propionic acid, sulfonic acids produce PTs with lower conductivities than iodine, but with higher environmental stabilities. Oxidative polymerization with ferric chloride can result in doping by residual catalyst, although matrix-assisted laser desorption/ionization mass spectrometry studies have shown that polys are partially halogenated by the residual oxidizing agent. Poly dissolved in toluene can be doped by solutions of ferric chloride hexahydrate dissolved in acetonitrile, can be cast into films with conductivities reaching 1 S/cm. Other, less common p-dopants include gold trifluoromethanesulfonic acid; the extended π-systems of conjugated PTs produce some of the most interesting properties of these materials—their optical properties. As an approximation, the conjugated backbone can be considered as a real-world example of the "electron-in-a-box" solution to the Schrödinger equation.
Conjugation relies upon overlap of the π-orbitals of the aromatic rings, which, in turn, requires the thiophene rings to be coplanar. The number of coplanar rings determines the conjugation length—the longer the conjugation length, the lower the separation between adjacent energy levels, the longer the absorption wavelength. Deviation from coplanarity may be permanent, resulting from mislinkages during synthesis or bulky side chains; this twist in the backbone reduces the conjugation length, the separation between energy levels is increased. This results in a shorter absorption wavelength. Determining the maximum effective conjugation length requires the synthesis of regioregular PTs of defined length; the absorption band in the visible region is red-shifted as the conjugation length increases, the maximum effective conjugation length is calculated as the saturation point of the red-shift. Early studies by ten Hoeve et al. estimated that the effective conjugation extended over 11 repeat units, while studies increased this estimate to 20 units.
Using the absorbance and emission profile of discrete conjugated oligos prepared through polymerization and separation, Lawrence et al. determined the effective conjugation length of poly to be 14 units. The effective conjugation length of polythiophene derivatives depend on the chemical structure of side chains, thiophene backbones. A variety of environmental factors can cause the conjugated backbone to twist, reducing the conjugation length and causing an absorption band shift, including solvent, application of an electric field, dissolved ions; the absorption band of poly in aqueous solutions of poly shifts from 480 nm at pH 7 to 415 nm at pH 4. This is attributed to formation of a compact coil structure, which can form hydrogen bonds with PVA upon partial deprotonation of the acetic acid group. Shifts in PT absorption bands due to changes in temperature r
Hot air oven
Hot air ovens are electrical devices which use dry heat to sterilize. They were developed by Pasteur, they can be operated from 50 to 300 °C, using a thermostat to control the temperature. Their double walled insulation keeps the heat in and conserves energy, the inner layer being a poor conductor and outer layer being metallic. There is an air filled space in between to aid insulation. An air circulating fan helps in uniform distribution of the heat; these are fitted with the adjustable wire mesh plated trays or aluminium trays and may have an on/off rocker switch, as well as indicators and controls for temperature and holding time. The capacities of these ovens vary. Power supply needs vary from country depending on the voltage and frequency used. Temperature sensitive tapes or biological indicators using bacterial spores can be used as controls, to test for the efficacy of the device during use, they do not require water and there is not much pressure build up within the oven, unlike an autoclave, making them safer to work with.
This makes them more suitable to be used in a laboratory environment. They can still be as effective, they can be more rapid than an autoclave and higher temperatures can be reached compared to other means. As they use dry heat instead of moist heat, some organisms like prions, may not be killed by them every time, based on the principle of thermal inactivation by oxidation. A complete cycle involves heating the oven to the required temperature, maintaining that temperature for the proper time interval for that temperature, turning the machine off and cooling the articles in the closed oven till they reach room temperature; the standard settings for a hot air oven are: 1.5 to 2 hours at 160 °C 6 to 12 minutes at 190 °C....plus the time required to preheat the chamber before beginning the sterilization cycle. If the door is opened before time, heat escapes and the process becomes incomplete, thus the cycle must be properly repeated all over. These are used to sterilize articles that can withstand high temperatures and not get burnt, like glassware and powders.
Linen gets burnt and surgical sharps lose their sharpness. Textbook of Microbiology by Prof. C P Baveja, ISBN 81-7855-266-3 Textbook of Microbiology by Ananthanarayan and Panikar, ISBN 81-250-2808-0 http://www.tpub.com/content/medical/14274/css/14274_146.htm
A Meker–Fisher burner, or Meker burner, is a laboratory burner that produces multiple open gas flames, used for heating and combustion. It is used when laboratory work requires a hotter flame than attainable using a Bunsen burner, or used when a larger-diameter flame is desired, such as with an inoculation loop or in some glassblowing operations; the burner was introduced by French chemist Georges Méker in an article published in 1905. The Meker–Fisher burner heat output can be in excess of 12,000 BTU per hour using LP gas. Flame temperatures of up to 1,100–1,200 °C are achievable. Compared with a Bunsen burner, the lower part of its tube has more openings with larger total cross-section, admitting more air and facilitating better mixing of air and gas; the tube is wider, its top is covered with a plate mesh, which separates the flame into an array of smaller flames with a common external envelope, ensures uniform heating, preventing flashback to the bottom of the tube, a risk at high air-to-fuel ratios and limits the maximal rate of air intake in a Bunsen burner.
The flame burns unlike the Bunsen or Teclu burners. Bunsen burner Teclu burner Video of Meker burner in use