A file is a tool used to remove fine amounts of material from a workpiece. It is common in woodworking and other similar trade and hobby tasks. Most are hand tools, made of a case hardened steel bar of rectangular, triangular, or round cross-section, with one or more surfaces cut with sharp parallel teeth. A narrow, pointed tang is common at one end. A rasp is a form of file with distinct, individually cut teeth used for coarsely removing large amounts of material. Files have been developed with abrasive surfaces, such as natural or synthetic diamond grains or silicon carbide, allowing removal of material that would dull or resist metal, such as ceramic. Early filing or rasping has prehistoric roots and grew out of the blending of the twin inspirations of cutting with stone cutting tools and abrading using natural abrasives, such as well-suited types of stone. Relatedly, lapping is quite ancient, with wood and beach sand offering a natural pair of lap and lapping compound; the Disston authors state, "To abrade, or file, ancient man used sand, coral, fish skin, gritty woods,—also stone of varying hardness in connection with sand and water."The Bronze Age and the Iron Age had various kinds of files and rasps.
Archaeologists have discovered rasps made from bronze in Egypt, dating back to the years 1200–1000 BC. Archaeologists have discovered rasps made of iron used by the Assyrians, dating back to the 7th Century BC. During the Middle Ages files were quite advanced, thanks to the extensive talents of blacksmiths. By the 11th century, there existed hardened files that would seem quite modern to today's eyes, but although they existed, could have spread in a geographical sense, via trade, they were not widespread in the cultural sense of the word—that is, most people, many smiths, did not have them. For example, in the 13th century, ornamental iron work at Paris was done skillfully with the aid of files, but the process was a secret known only to a master craftsman; the Disston authors state, "It was not until the fourteenth century, that those who practiced art in ironwork began to use other tools, besides heat and the hammer, regularly." This statement could mislead in the sense that stoning and lapping have never been rare activities among humans, or smiths.
But the point is that modern iron or steel files, with teeth and hardening, the material culture of intricate filing that would lead to locksmithing and gunsmithing, for example, are what took time to become common. But by the late Middle Ages, the transition was extensive; the Disston authors mention Nuremberg and Remscheid as leading centers of production for files as well as tools in general. The activity in Remscheid reflects the metalworking spirit of the Rhine-Ruhr region in general rather than representing a single village of geniuses in isolation. Most files of the period were smithed by hand in a sequence in which the iron was forged the teeth were cut with a chisel, the piece was hardened, followed sometimes by tempering. Among the drawings of Leonardo da Vinci is a sketch of a machine tool for the cutting of files. Prior to the industrialization of machining and the development of interchangeable parts during the 19th century, filing was much more important in the construction of mechanisms.
Component parts were shaped by forging, by primitive machining operations. These components were individually hand-fit for assembly by careful and deliberate filing; the potential precision of such fitting is much higher than assumed, but the components of such hand-fit assemblies are decidedly not interchangeable with those from another assembly. Locks and firearms were manufactured in this way for centuries before the Industrial Revolution. Machining in the mid-19th century was dependent on filing, because milling practice was evolving out of its infancy; as late as the early 20th century, manufacturing involved filing parts to precise shape and size. In today's manufacturing environment and grinding have replaced this type of work, filing tends to be for deburring only. Skillful filing to shape and size is still a part of diemaking, toolmaking, etc. but in those fields, the goal is to avoid handwork when possible. Files come in a wide variety of materials, shapes and tooth configurations; the cross-section of a file can be flat, half-round, square, knife edge or of a more specialized shape.
Steel files may be through hardened or case hardened. There is no unitary international standard for file nomenclature. A file is "blunt" if its sides and width are both parallel throughout i
A hot plate is a portable self-contained tabletop small appliance cooktop that features one, two or more electric heating elements or gas burners. A hot plate can be used as a stand-alone appliance, but is used as a substitute for one of the burners from an oven range or a kitchen stove. Hot plates are used for food preparation in locations where a full kitchen stove would not be convenient or practical. A hot plate can have a flat round surface. Hot plates can be used in areas without electricity; this type of cooking equipment is powered by electricity. In laboratory settings, hot plates are used to heat glassware or its contents; some hot plates contain a magnetic stirrer, allowing the heated liquid to be stirred automatically. In a student laboratory, hot plates are used because baths can be hazards if they spill, overheat or ignite because they have high thermal inertia and mantles can be expensive and are designed for specific flask volumes. Two alternative methods for heating glassware using a hotplate are available.
One method is to suspend glassware above the surface of the plate with no direct contact. This not only reduces the temperature of the glass, but it slows down the rate of heat exchange and encourages heating; this works well for low boiling point operations or when a heat source's minimum temperature is high. Another method, called a teepee setup because it looks a little like a tipi, is to suspend glassware above a plate and surround the flask by a skirt of tinfoil; the skirt should start at the neck of the flask and drape down to the surface of the plate, not touching the sides of the flask, but covering the majority of the plates surface. This method is for glassware to be heated at higher temperatures because the flask is warmed indirectly by the hot air collecting under the skirt and unlike suspending the glassware, this method is better protected from drafts. Both these methods are useful in a student laboratory as they are cheaper, effective and the user does not have to wait for a bath to cool down after use.
Hot plates are used for many industrial applications. These hot plates vary in size from 2 to over 300 square centimetres. Typical operating temperatures vary from 100 to 750°C and power requirements are in the 120 to 480 volt range. Most industrial hot plates will withstand loads more than 150 pounds. Industrial hot plates which incorporate a porous heated plate are referred to as heated chucks; these plates are used to heat thin films evenly by drawing the film on the plate with a vacuum. These plates are used in the process of manufacturing semiconductors. Hot plates using special material and protective coatings are used in mining and related industries to heat samples of toxic chemicals; such hot plates are referred to as corrosion-resistant hot plates. Hot plates are used in the electronics industry as a method of soldering and desoldering components onto circuit boards. Hot plates with two heating surfaces are used to fuse plastic pipes. Many of these pipes are over 90-centimeter diameter.
The two pipes to be fused are pressed against the plate. The plate is removed and the two pipes are pressed together and bonded; this process is called butt fusion. Bachelor griller Blech, a sheet of metal that may be placed over cooking burners to help in the observation of the Jewish Sabbath Griddle, a flat heated cooking surface, maybe a pan, a gas powered version or in table-top electrical appliance form Heating element, a material that converts electrical energy to heat through resistance List of stoves Portable stove, a portable cooking device that may burn liquid or gas fuel Definitions: Hot plate Important notes.
Laboratory water bath
A water bath is laboratory equipment made from a container filled with heated water. It is used to incubate samples in water at a constant temperature over a long period of time. All water baths have an analogue interface to allow users to set a desired temperature. Utilisations include melting of substrates or incubation of cell cultures, it is used to enable certain chemical reactions to occur at high temperature. Water bath is a preferred heat source for heating flammable chemicals instead of an open flame to prevent ignition. Different types of water baths are used depending on application. For all water baths, it can be used up to 99.9 °C. When temperature is above 100 °C, alternative methods such as oil bath, silicone bath or sand bath may be used. Use with caution, it is not recommended to use water bath with moisture pyrophoric reactions. Do not heat a bath fluid above its flash point. Water level should be monitored, filled with distilled water only; this is required to prevent salts from depositing on the heater.
Disinfectants can be added to prevent growth of organisms. Raise the temperature to 90 °C or higher to once a week for half an hour for the purpose of decontamination. Markers tend to come off in water baths. Use water resistant ones. If application involves liquids that give off fumes, it is recommended to operate water bath in fume hood or in a well ventilated area; the cover is closed to help reaching high temperatures. Set up on a steady surface away from flammable materials. Circulating the water baths are ideal for applications when temperature uniformity and consistency are critical, such as enzymatic and serologic experiments. Water is circulated throughout the bath resulting in a more uniform temperature; this type of water bath relies on convection instead of water being uniformly heated. Therefore, it is less accurate in terms of temperature control. In addition, there are add-ons that provide stirring to non-circulating water baths to create more uniform heat transfer; this type of water bath has extra control for shaking.
This shaking feature can be turned off. In microbiological practices, constant shaking allows liquid-grown cell cultures grown to mix with the air; some key benefits of shaking water bath are user-friendly operation via keypad, convenient bath drains, adjustable shaking frequencies, bright LED-display, optional lift-up bath cover, power switch integrated in keypad and warning and cut-off protection for low/high temperature. Thermal immersion circulator Heated bath Hot plate Sand bath Oil bath
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
A clamp holder or clamp fastener is a piece of laboratory apparatus, used to secure laboratory clamps, such as extension-type utility clamps, or other attachments to a ring stand or lab frame. The material can be made up of cast iron, stainless steel, aluminium or nickel-plated zinc. A ring-stand rod and clamp are inserted into two jaws of a clamp holder and adjustable thumbscrews fasten the clamp holder to the attachments and lock it in place; the attachments can be secured with the thumbscrews to be positioned at any height or angle, with a regular clamp holder positioning the apparatus at a 90° angle. Clamp holders can secure laboratory equipment at specific angles and weights, as required. Clamp holders are used to hold the attached apparatus over a work surface. There are several different types of holders, such as swivel holders and all-position holders, that allow adjustments for different angles and planes. In some cases it can be used to attach support rods together. Retort Stand Utility Clamp Iron Ring
A microscope is an instrument used to see objects that are too small to be seen by the naked eye. Microscopy is the science of investigating small structures using such an instrument. Microscopic means invisible to the eye. There are many types of microscopes, they may be grouped in different ways. One way is to describe the way the instruments interact with a sample to create images, either by sending a beam of light or electrons to a sample in its optical path, or by scanning across, a short distance from the surface of a sample using a probe; the most common microscope is the optical microscope, which uses light to pass through a sample to produce an image. Other major types of microscopes are the fluorescence microscope, the electron microscope and the various types of scanning probe microscopes. Although objects resembling lenses date back 4000 years and there are Greek accounts of the optical properties of water-filled spheres followed by many centuries of writings on optics, the earliest known use of simple microscopes dates back to the widespread use of lenses in eyeglasses in the 13th century.
The earliest known examples of compound microscopes, which combine an objective lens near the specimen with an eyepiece to view a real image, appeared in Europe around 1620. The inventor is unknown. Several revolve around the spectacle-making centers in the Netherlands including claims it was invented in 1590 by Zacharias Janssen and/or Zacharias' father, Hans Martens, claims it was invented by their neighbor and rival spectacle maker, Hans Lippershey, claims it was invented by expatriate Cornelis Drebbel, noted to have a version in London in 1619. Galileo Galilei seems to have found after 1610 that he could close focus his telescope to view small objects and, after seeing a compound microscope built by Drebbel exhibited in Rome in 1624, built his own improved version. Giovanni Faber coined the name microscope for the compound microscope Galileo submitted to the Accademia dei Lincei in 1625; the first detailed account of the microscopic anatomy of organic tissue based on the use of a microscope did not appear until 1644, in Giambattista Odierna's L'occhio della mosca, or The Fly's Eye.
The microscope was still a novelty until the 1660s and 1670s when naturalists in Italy, the Netherlands and England began using them to study biology. Italian scientist Marcello Malpighi, called the father of histology by some historians of biology, began his analysis of biological structures with the lungs. Robert Hooke's Micrographia had a huge impact because of its impressive illustrations. A significant contribution came from Antonie van Leeuwenhoek who achieved up to 300 times magnification using a simple single lens microscope, he sandwiched a small glass ball lens between the holes in two metal plates riveted together, with an adjustable-by-screws needle attached to mount the specimen. Van Leeuwenhoek re-discovered red blood cells and spermatozoa, helped popularise the use of microscopes to view biological ultrastructure. On 9 October 1676, van Leeuwenhoek reported the discovery of micro-organisms; the performance of a light microscope depends on the quality and correct use of the condensor lens system to focus light on the specimen and the objective lens to capture the light from the specimen and form an image.
Early instruments were limited until this principle was appreciated and developed from the late 19th to early 20th century, until electric lamps were available as light sources. In 1893 August Köhler developed a key principle of sample illumination, Köhler illumination, central to achieving the theoretical limits of resolution for the light microscope; this method of sample illumination produces lighting and overcomes the limited contrast and resolution imposed by early techniques of sample illumination. Further developments in sample illumination came from the discovery of phase contrast by Frits Zernike in 1953, differential interference contrast illumination by Georges Nomarski in 1955. In the early 20th century a significant alternative to the light microscope was developed, an instrument that uses a beam of electrons rather than light to generate an image; the German physicist, Ernst Ruska, working with electrical engineer Max Knoll, developed the first prototype electron microscope in 1931, a transmission electron microscope.
The transmission electron microscope works on similar principles to an optical microscope but uses electrons in the place of light and electromagnets in the place of glass lenses. Use of electrons, instead of light, allows for much higher resolution. Development of the transmission electron microscope was followed in 1935 by the development of the scanning electron microscope by Max Knoll. Although TEMs were being used for research before WWII, became popular afterwards, the SEM was not commercially available until 1965. Transmission electron microscopes became popular following the Second World War. Ernst Ruska, working at Siemens, developed the first commercial transmission electron microscope and, in the 1950s, major scientific conferences on electron microscopy started being held. In 1965, the first commercial scanning electron microscope was developed by Profess