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Electrostatic Detection Device
An electrostatic detection device, or EDD, is a specialized piece of equipment commonly used in questioned document examination to reveal indentations or impressions in paper that may otherwise go unnoticed. It is a non-destructive technique (will not damage the evidence in question), allowing further tests to be carried out. It is a sensitive technique capable of detecting indentations on pages several layers below the top sheet and many years after the indentations were created. EDD equipment and investigative techniques were central to overturning a number of convictions in the United Kingdom, as it was possible to demonstrate that witness statements had been altered or signed as blank pages in reverse order to the main notes. This was central in a number of cases investigated at the West Midlands Serious Crime Squad that were appealed. The allegations of tampering with evidence and witness statements led to the unit being disbanded, and over 60 convictions being quashed, many of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Questioned Document Examination
In forensic science, questioned document examination (QDE) is the examination of documents potentially disputed in a court of law. Its primary purpose is to provide evidence about a suspicious or questionable document using scientific processes and methods. Evidence might include alterations, the chain of possession, damage to the document, forgery, origin, authenticity, or other questions that come up when a document is challenged in court. Overviews Many QDE involve a comparison of the questioned document, or components of the document, to a set of known standards. The most common type of examination involves handwriting wherein the examiner tries to address concerns about potential authorship. A document examiner is often asked to determine if a questioned item originated from the same source as the known item(s), then present their opinion on the matter in court as an expert witness. Other common tasks include determining what has happened to a document, determining when a d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ninhydrin
Ninhydrin (2,2-dihydroxyindane-1,3-dione) is an organic compound with the formula C6H4(CO)2C(OH)2. It is used to detect ammonia and amines. Upon reaction with these amines, ninhydrin gets converted into deep blue or purple derivatives, which are called Ruhemann's purple. Ninhydrin is most commonly used to detect fingerprints, as the terminal amines of lysine residues in peptides and proteins sloughed off in fingerprints react with ninhydrin. Ninhydrin is a white solid that is soluble in ethanol and acetone. Ninhydrin can be considered as the hydrate of indane-1,2,3-trione. History Ninhydrin was discovered in 1910 by the German-English chemist Siegfried Ruhemann (1859–1943). In the same year, Ruhemann observed ninhydrin's reaction with amino acids. In 1954, Swedish investigators Oden and von Hofsten proposed that ninhydrin could be used to develop latent fingerprints. Uses Ninhydrin can also be used to monitor deprotection in solid phase peptide synthesis (Kaiser test). The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Forensic Equipment
Forensic science, also known as criminalistics, is the application of science to criminal and civil laws, mainly—on the criminal side—during criminal investigation, as governed by the legal standards of admissible evidence and criminal procedure. Forensic science is a broad field that includes; DNA analysis, fingerprint analysis, blood stain pattern analysis, firearms examination and ballistics, tool mark analysis, serology, toxicology, hair and fiber analysis, entomology, questioned documents, anthropology, odontology, pathology, epidemiology, footwear and tire tread analysis, drug chemistry, paint and glass analysis, digital audio video and photo analysis. Forensic scientists collect, preserve, and analyze scientific evidence during the course of an investigation. While some forensic scientists travel to the scene of the crime to collect the evidence themselves, others occupy a laboratory role, performing analysis on objects brought to them by other individuals. Still ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triboelectric
The triboelectric effect (also known as triboelectric charging) is a type of contact electrification on which certain materials become electrically charged after they are separated from a different material with which they were in contact. Rubbing the two materials with each other increases the contact between their surfaces, and hence the triboelectric effect. Rubbing glass with fur for example, or a plastic comb through the hair, can build up triboelectricity. Most everyday static electricity is triboelectric. The polarity and strength of the charges produced differ according to the materials, surface roughness, temperature, strain, and other properties. The triboelectric effect is very unpredictable, and only broad generalizations can be made. Amber, for example, can acquire an electric charge by contact and separation (or friction) with a material like wool. This property was first recorded by Thales of Miletus. The word "electricity" is derived from William Gilbert's initi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrophotography
Xerography is a dry photocopying technique. Originally called electrophotography, it was renamed xerography—from the roots el, ξηρός, label=none ''xeros'', meaning "dry" and -γραφία ''-graphia'', meaning "writing"—to emphasize that unlike reproduction techniques then in use such as cyanotype, the process of xerography used no liquid chemicals. History Xerography was invented by American physicist Chester Carlson, based significantly on contributions by Hungarian physicist Pál Selényi. Carlson applied for and was awarded on October 6, 1942. Carlson's innovation combined electrostatic printing with photography, unlike the dry electrostatic printing process invented by Georg Christoph Lichtenberg in 1778. Carlson's original process was cumbersome, requiring several manual processing steps with flat plates. In 1946, Carlson signed an agreement with Haloid Photographic Company to develop it as a commercial product. Before that year, Carlson had proposed his ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrostatic
Electrostatics is a branch of physics that studies electric charges at rest (static electricity). Since classical times, it has been known that some materials, such as amber, attract lightweight particles after rubbing. The Greek word for amber, (), was thus the source of the word 'electricity'. Electrostatic phenomena arise from the forces that electric charges exert on each other. Such forces are described by Coulomb's law. Even though electrostatically induced forces seem to be rather weak, some electrostatic forces are relatively large. The force between an electron and a proton, which together make up a hydrogen atom, is about 36 orders of magnitude stronger than the gravitational force acting between them. There are many examples of electrostatic phenomena, from those as simple as the attraction of plastic wrap to one's hand after it is removed from a package, to the apparently spontaneous explosion of grain silos, the damage of electronic components during manufacturi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paper Size
Paper size standards govern the size of sheets of paper used as writing paper, stationery, cards, and for some printed documents. The ISO 216 standard, which includes the commonly used A4 size, is the international standard for paper size. It is used across the world except in North America and parts of Central and South America, where North American paper sizes such as "Letter" and "Legal" are used. The international standard for envelopes is the C series of ISO 269. International paper sizes The international paper size standard is ISO 216. It is based on the German DIN 476 standard for paper sizes. ISO paper sizes are all based on a single aspect ratio of the square root of 2, or approximately 1:1.41421. There are different series, as well as several extensions. The following international paper sizes are included in Cascading Style Sheets (CSS): ''A3'', ''A4'', ''A5'', ''B4'', ''B5''. A series There are 11 sizes in the A series, designated A0–A10, al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fingerprint
A fingerprint is an impression left by the friction ridges of a human finger. The recovery of partial fingerprints from a crime scene is an important method of forensic science. Moisture and grease on a finger result in fingerprints on surfaces such as glass or metal. Deliberate impressions of entire fingerprints can be obtained by ink or other substances transferred from the peaks of friction ridges on the skin to a smooth surface such as paper. Fingerprint records normally contain impressions from the pad on the last joint of fingers and thumbs, though fingerprint cards also typically record portions of lower joint areas of the fingers. Human fingerprints are detailed, nearly unique, difficult to alter, and durable over the life of an individual, making them suitable as long-term markers of human identity. They may be employed by police or other authorities to identify individuals who wish to conceal their identity, or to identify people who are incapacitated or deceased and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poison Pen Letter
A poison pen letter is a letter or note containing unpleasant, abusive, or malicious statements or accusations about the recipient or a third party. It is usually sent anonymously. In the term "poison pen" (or poisoned pen), the word poison is used figuratively, rather than literally. Poison pen letters are usually composed and sent to upset the recipient. They differ from blackmail, which is intended to obtain something from the recipient. In the United Kingdom, Section 1 of the Malicious Communications Act 1988 covers most cases of poison pen letters. See also * Ransom note effect – A message composed of multiple juxtaposing typefaces * James Forster (poison pen letter writer) * Hate mail * Chain letter * Stalking Stalking is unwanted and/or repeated surveillance by an individual or group toward another person. Stalking behaviors are interrelated to harassment and intimidation and may include following the victim in person or monitoring them. The ter ... Reference ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Contract
A contract is a legally enforceable agreement between two or more parties that creates, defines, and governs mutual rights and obligations between them. A contract typically involves the transfer of goods, services, money, or a promise to transfer any of those at a future date. In the event of a breach of contract, the injured party may seek judicial remedies such as damages or rescission. Contract law, the field of the law of obligations concerned with contracts, is based on the principle that agreements must be honoured. Contract law, like other areas of private law, varies between jurisdictions. The various systems of contract law can broadly be split between common law jurisdictions, civil law jurisdictions, and mixed law jurisdictions which combine elements of both common and civil law. Common law jurisdictions typically require contracts to include consideration in order to be valid, whereas civil and most mixed law jurisdictions solely require a meeting of the mind ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
