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Explosive Vapor Detector
Explosive vapor detectors (EVD) are explosives detection instruments whose principle of operation is the selective analysis of collected vapor samples from the air, in contrast to explosives trace detectors (ETD) which require the physical collection of particulate samples from surfaces. EVDs are not limited to explosives, and may also be used to detect narcotics and other illicit or dangerous substances such as biological agents or chemical warfare agents. EVDs can be classified into two types: portable EVDs, and pre-concentrated sample EVDs. Portable units have detection limits in the ranges of parts per million or parts per billion, similar to those of ETDs or explosive detection dogs. Pre-concentrated sample EVDs have sensitivities in the range of parts per quadrillion (10−15). Principle of operation The detection process is based on two broad steps: sampling and analysis. In portable instruments, sampling and the analysis are done on the same device. Sampling A samp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Explosives Detection
Explosive detection is a non-destructive inspection process to determine whether a container contains explosive material. Explosive detection is commonly used at airports, ports and for border control. Detection tools Colorimetrics & automated colorimetrics The use of colorimetric test kits for explosive detection is one of the most simple methods for officers, and widely used method for the detection of explosives. Colorimetric detection of explosives involves applying a chemical reagent to an unknown material or sample and observing a color reaction. Common color reactions are known and indicate to the user if there is an explosive material present and in many cases the group of explosives from which the material is derived. The major groups of explosives are Nitroaromatic compound, nitroaromatic, nitrate ester, and Nitroamine, nitramine explosives, as well as inorganic nitrate-based explosives. Other groups include chlorates and peroxides which are not nitro based explosives. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mass Spectrometry
Mass spectrometry (MS) is an analytical technique that is used to measure the mass-to-charge ratio of ions. The results are presented as a ''mass spectrum'', a plot of intensity as a function of the mass-to-charge ratio. Mass spectrometry is used in many different fields and is applied to pure samples as well as complex mixtures. A mass spectrum is a type of plot of the ion signal as a function of the mass-to-charge ratio. These spectra are used to determine the elemental or isotopic signature of a sample, the masses of particles and of molecules, and to elucidate the chemical identity or structure of molecules and other chemical compounds. In a typical MS procedure, a sample, which may be solid, liquid, or gaseous, is ionization, ionized, for example by bombarding it with a Electron ionization, beam of electrons. This may cause some of the sample's molecules to break up into positively charged fragments or simply become positively charged without fragmenting. These ions (fragmen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
European Civil Aviation Conference
The European Civil Aviation Conference (ECAC) or Conférence Européenne de l'Aviation Civile (CEAC) is an intergovernmental organization which was established by the International Civil Aviation Organization (ICAO) and the Council of Europe. It is located in Neuilly-sur-Seine in France. Founded in 1955 with 19 member states, the ECAC now totals 44 members, including all 27 EU, 31 of the 32 European Aviation Safety Agency member states, and all 41 EUROCONTROL member states. ECAC "promotes the continued development of a safe, efficient and sustainable European air transport system. In doing so, it seeks to harmonise civil aviation policies and practices amongst its Member States and promote understanding on policy matters between its Member States and other parts of the world." Its strategic priorities are safety, security and the environment. Membership ECAC, EUROCONTROL and EU members: * Austria (1955) * Belgium (1955) * Bulgaria (1991) * Croatia (1992) * Cyprus (1969) * C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Breath Analysis
Exhaled breath analysis is a method in medicine for gaining information on the clinical state of an individual by monitoring the components present in the exhaled breath. It is a non-invasive method and breath samples can be extracted as often as desired. Identification and quantification of potential disease biomarkers can be seen as the driving force for the analysis of exhaled breath. Moreover, future applications for medical diagnosis and therapy control with dynamic assessments of normal physiological function or pharmacodynamics are intended. Breath analysis is performed using various approaches for sampling and analysis. Breath gas analysis consists of the analysis of volatile organic compounds, for example in blood alcohol testing, and various analytical methods can be applied. Breath aerosol analysis consists in the sampling and analysis of particles emitted in the respiratory tract and present in exhaled breath. This is a relatively new field that holds great promise ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Demining
Demining or mine clearance is the process of removing land mines from an area. In military operations, the object is to rapidly clear a path through a minefield, and this is often done with devices such as mine plows and blast waves. By contrast, the goal of ''humanitarian demining'' is to remove all of the landmines to a given depth and make the land safe for human use. Specially trained dogs are also used to narrow down the search and verify that an area is cleared. Mechanical devices such as flails and excavators are sometimes used to clear mines. A great variety of methods for detecting landmines have been studied. These include electromagnetic methods, one of which (ground penetrating radar) has been employed in tandem with metal detectors. Acoustic methods can sense the cavity created by mine casings. Sensors have been developed to detect vapor leaking from landmines. Animals such as rats and mongooses can safely move over a minefield and detect mines, and animals can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Food Fraud
Counterfeit consumer goods are goods illegally made or sold without the brand owner's authorization, often violating trademarks. Counterfeit goods can be found in nearly every industry, from luxury products like designer handbags and watches to everyday goods like electronics and medications. Typically of lower quality, counterfeit goods may pose health and safety risks. Various organizations have attempted to estimate the size of the global counterfeit market. According to the OECD, counterfeit goods made up approximately 2.5% of global trade in 2019, with an estimated value of $464 billion. Sales of counterfeit and pirated goods are projected to reach €1.67 trillion (approximately $1.89 trillion USD) by 2030. Despite the illegality of counterfeit items, many counterfeit items, especially fashion items such as handbags, watches, shoes and sports jerseys, are widely sold in many regions and are purchased by both locals and tourists, typically at markets in Africa, Asia, Lati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Detection Rate
In medicine and statistics, sensitivity and specificity mathematically describe the accuracy of a test that reports the presence or absence of a medical condition. If individuals who have the condition are considered "positive" and those who do not are considered "negative", then sensitivity is a measure of how well a test can identify true positives and specificity is a measure of how well a test can identify true negatives: * Sensitivity (true positive rate) is the probability of a positive test result, conditioned on the individual truly being positive. * Specificity (true negative rate) is the probability of a negative test result, conditioned on the individual truly being negative. If the true status of the condition cannot be known, sensitivity and specificity can be defined relative to a " gold standard test" which is assumed correct. For all testing, both diagnoses and screening, there is usually a trade-off between sensitivity and specificity, such that higher sensiti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Imaging
Imaging is the representation or reproduction of an object's form; especially a visual representation (i.e., the formation of an image). Imaging technology is the application of materials and methods to create, preserve, or duplicate images. Imaging science is a multidisciplinary field concerned with the generation, collection, duplication, analysis, modification, and visualization of images,Joseph P. Hornak, ''Encyclopedia of Imaging Science and Technology'' (John Wiley & Sons, 2002) including imaging things that the human eye cannot detect. As an evolving field it includes research and researchers from physics, mathematics, electrical engineering, computer vision, computer science, and perceptual psychology. ''Imager, Imagers'' are imaging sensors. Imaging chain The foundation of imaging science as a discipline is the "imaging chain" – a conceptual model describing all of the factors which must be considered when developing a system for creating visual renderings (image ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vapor Pressure
Vapor pressure or equilibrium vapor pressure is the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases (solid or liquid) at a given temperature in a closed system. The equilibrium vapor pressure is an indication of a liquid's thermodynamic tendency to evaporate. It relates to the balance of particles escaping from the liquid (or solid) in equilibrium with those in a coexisting vapor phase. A substance with a high vapor pressure at normal temperatures is often referred to as '' volatile''. The pressure exhibited by vapor present above a liquid surface is known as vapor pressure. As the temperature of a liquid increases, the attractive interactions between liquid molecules become less significant in comparison to the entropy of those molecules in the gas phase, increasing the vapor pressure. Thus, liquids with strong intermolecular interactions are likely to have smaller vapor pressures, with the reverse true for weaker interactions. The vapor p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sensor Resolution
A sensor is often defined as a device that receives and responds to a signal or stimulus. The stimulus is the quantity, property, or condition that is sensed and converted into electrical signal. In the broadest definition, a sensor is a device, module, machine, or subsystem that detects events or changes in its environment and sends the information to other electronics, frequently a computer processor. Sensors are used in everyday objects such as touch-sensitive elevator buttons (tactile sensor) and lamps which dim or brighten by touching the base, and in innumerable applications of which most people are never aware. With advances in micromachinery and easy-to-use microcontroller platforms, the uses of sensors have expanded beyond the traditional fields of temperature, pressure and flow measurement, for example into MARG sensors. Analog sensors such as potentiometers and force-sensing resistors are still widely used. Their applications include manufacturing and machinery, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Standard Atmosphere (unit)
The standard atmosphere (symbol: atm) is a unit of pressure defined as Pa. It is sometimes used as a ''reference pressure'' or ''standard pressure''. It is approximately equal to Earth's average atmospheric pressure at sea level. History The standard atmosphere was originally defined as the pressure exerted by a 760 mm column of mercury at and standard gravity (''g''n = ). It was used as a reference condition for physical and chemical properties, and the definition of the centigrade temperature scale set 100 °C as the boiling point of water at this pressure. In 1954, the 10th General Conference on Weights and Measures (CGPM) adopted ''standard atmosphere'' for general use and affirmed its definition of being precisely equal to dynes per square centimetre (). This defined pressure in a way that is independent of the properties of any particular substance. In addition, the CGPM noted that there had been some misapprehension that the previous definition (from the 9th CGPM ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
