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PH Helmet
The P helmet, PH helmet and PHG helmet were early types of gas mask issued by the British Army in the First World War, to protect troops against chlorine, phosgene and tear gases. Rather than having a separate filter for removing the toxic chemicals, they consisted of a gas-permeable hood worn over the head which was treated with chemicals. The P (or Phenate) Helmet, officially called the Tube Helmet, appeared in July 1915, replacing the simpler Hypo Helmet. It featured two mica eyepieces instead of the single visor of its predecessor, and added an exhale valve fed from a metal tube which the wearer held in his mouth. The exhale valve was needed because a double layer of flannel – one treated and one not – was needed because the solution attacked the fabric. It had flannel layers of cloth-dipped in sodium phenolate and glycerin and protected against chlorine and phosgene, but not against tear gas. Around 9 million were made. The PH Helmet (Phenate Hexamine) replaced i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vickers Machine Gun Crew With Gas Masks
Vickers was a British engineering company that existed from 1828 until 1999. It was formed in Sheffield as a steel foundry by Edward Vickers and his father-in-law, and soon became famous for casting church bells. The company went public in 1867, acquired more businesses, and began branching out into military hardware and shipbuilding. In 1911, the company expanded into aircraft manufacture and opened a flying school. They expanded even further into electrical and railway manufacturing, and in 1928 acquired an interest in the Supermarine. Beginning in the 1960s, various parts of the company were nationalised, and in 1999 the rest of the company was acquired by Rolls-Royce plc, who sold the defence arm to Alvis plc. The Vickers name lived on in Alvis Vickers, until the latter was acquired by BAE Systems in 2004 to form BAE Systems Land Systems. History Early history Vickers was formed in Sheffield as a steel foundry by Edward Vickers and his father-in-law George Naylor in 18 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypo Helmet
The Hypo helmet, or British Smoke Hood (its official name), was an early British World War I gas mask, designed by Cluny MacPherson. Earlier designs The German army used poison gas for the first time against Entente troops at the Second Battle of Ypres, Belgium on 22 April 1915. As an immediate response, the British began issuing cotton wool wrapped in muslin to its troops by 3 May. This was followed by the Black Veil Respirator, invented by John Scott Haldane, which began to be issued to troops on 20 May 1915. The Black Veil was a cotton pad soaked in an absorbent solution which was secured over the mouth using black cotton veiling. The veiling could be drawn up to cover the eyes, providing some protection against lachrymatory agents, however the mask itself still only provided little protection against chlorine gas. It was also of fragile construction, required training to use effectively and largely immobilized men during a gas attack as they were concerned about their mask ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Cyanide
Hydrogen cyanide, sometimes called prussic acid, is a chemical compound with the formula HCN and structure . It is a colorless, extremely poisonous, and flammable liquid that boils slightly above room temperature, at . HCN is produced on an industrial scale and is a highly valued precursor to many chemical compounds ranging from polymers to pharmaceuticals. Large-scale applications are for the production of potassium cyanide and adiponitrile, used in mining and plastics, respectively. It is more toxic than solid cyanide compounds due to its volatile nature. Structure and general properties Hydrogen cyanide is a linear molecule, with a triple bond between carbon and nitrogen. The tautomer of HCN is HNC, hydrogen isocyanide. Hydrogen cyanide is weakly acidic with a p''K''a of 9.2. It partially ionizes in water solution to give the cyanide anion, CN−. A solution of hydrogen cyanide in water, represented as HCN, is called ''hydrocyanic acid''. The salts of the cyanid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexamethylene Tetramine
Hexamethylenetetramine, also known as methenamine, hexamine, or urotropin, is a heterocyclic organic compound with the formula (CH2)6N4. This white crystalline compound is highly soluble in water and polar organic solvents. It has a cage-like structure similar to adamantane. It is useful in the synthesis of other organic compounds, including plastics, pharmaceuticals, and rubber additives. It sublimes in vacuum at 280 °C. Synthesis, structure, reactivity Hexamethylenetetramine was discovered by Aleksandr Butlerov in 1859. In this article, Butlerov discovered formaldehyde, which he called "dioxymethylen" (methylene dioxide) age 247because his empirical formula for it was incorrect (C4H4O4). On pages 249–250, he describes treating formaldehyde with ammonia gas, creating hexamine. It is prepared industrially by combining formaldehyde and ammonia: : The reaction can be conducted in gas phase and in solution. The molecule has a tetrahedral cage-like structure, similar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glycerin
Glycerol (), also called glycerine in British English and glycerin in American English, is a simple triol compound. It is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. The glycerol backbone is found in lipids known as glycerides. Because it has antimicrobial and antiviral properties, it is widely used in wound and burn treatments approved by the U.S. Food and Drug Administration. Conversely, it is also used as a bacterial culture medium. It can be used as an effective marker to measure liver disease. It is also widely used as a sweetener in the food industry and as a humectant in pharmaceutical formulations. Because of its three hydroxyl groups, glycerol is miscible with water and is hygroscopic in nature. Structure Although achiral, glycerol is prochiral with respect to reactions of one of the two primary alcohols. Thus, in substituted derivatives, the stereospecific numbering labels the molecule with a "sn-" prefix before the stem name of the m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Phenolate
Sodium phenoxide (sodium phenolate) is an organic compound with the formula NaOC6H5. It is a white crystalline solid. Its anion, phenoxide, also known as phenolate, is the conjugate base of phenol. It is used as a precursor to many other organic compounds, such as aryl ethers. Synthesis and structure Most commonly, solutions of sodium phenoxide are produced by treating phenol with sodium hydroxide. Anhydrous derivatives can be prepared by combining phenol and sodium. A related, updated procedure uses sodium methoxide instead of sodium hydroxide: :NaOCH3 + HOC6H5 → NaOC6H5 + HOCH3 Sodium phenoxide can also be produced by the "alkaline fusion" of benzenesulfonic acid, whereby the sulfonate groups are displaced by hydroxide: :C6H5SO3Na + 2 NaOH → C6H5ONa + Na2SO3 This route once was the principal industrial route to phenol. Structure Like other sodium alkoxides, solid sodium phenoxide adopts a complex structure involving multiple Na-O bonds. Solvent-free material i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mica
Micas ( ) are a group of silicate minerals whose outstanding physical characteristic is that individual mica crystals can easily be split into extremely thin elastic plates. This characteristic is described as perfect basal cleavage. Mica is common in igneous and metamorphic rock and is occasionally found as small flakes in sedimentary rock. It is particularly prominent in many granites, pegmatites, and schists, and "books" (large individual crystals) of mica several feet across have been found in some pegmatites. Micas are used in products such as drywalls, paints, fillers, especially in parts for automobiles, roofing and shingles, as well as in electronics. The mineral is used in cosmetics and food to add "shimmer" or "frost." Properties and structure The mica group is composed of 37 phyllosilicate minerals. All crystallize in the monoclinic system, with a tendency towards pseudohexagonal crystals, and are similar in structure but vary in chemical composition. Micas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tear Gas
Tear gas, also known as a lachrymator agent or lachrymator (), sometimes colloquially known as "mace" after the early commercial aerosol, is a chemical weapon that stimulates the nerves of the lacrimal gland in the eye to produce tears. In addition, it can cause severe eye and respiratory pain, skin irritation, bleeding, and blindness. Common lachrymators both currently and formerly used as tear gas include pepper spray (OC gas), PAVA spray ( nonivamide), CS gas, CR gas, CN gas (phenacyl chloride), bromoacetone, xylyl bromide and Mace (a branded mixture). While lachrymatory agents are commonly deployed for riot control by law enforcement and military personnel, its use in warfare is prohibited by various international treaties.E.g. the Geneva Protocol of 1925 prohibited the use of "asphyxiating gas, or any other kind of gas, liquids, substances or similar materials". During World War I, increasingly toxic and deadly lachrymatory agents were used. The short and long- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
A World War I British Gas Hood C
A, or a, is the first Letter (alphabet), letter and the first vowel of the Latin alphabet, Latin alphabet, used in the English alphabet, modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is English alphabet#Letter names, ''a'' (pronounced ), plural English alphabet#Letter names, ''aes''. It is similar in shape to the Greek alphabet#History, Ancient Greek letter alpha, from which it derives. The Letter case, uppercase version consists of the two slanting sides of a triangle, crossed in the middle by a horizontal bar. The lowercase version can be written in two forms: the double-storey a and single-storey ɑ. The latter is commonly used in handwriting and fonts based on it, especially fonts intended to be read by children, and is also found in italic type. In English grammar, "English articles, a", and its variant "English articles#Indefinite article, an", are Article (grammar)#Indefinite article, indefinite arti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosgene
Phosgene is the organic chemical compound with the formula COCl2. It is a toxic, colorless gas; in low concentrations, its musty odor resembles that of freshly cut hay or grass. Phosgene is a valued and important industrial building block, especially for the production of precursors of polyurethanes and polycarbonate plastics. Phosgene is extremely poisonous and was used as a chemical weapon during World War I, where it was responsible for 85,000 deaths. It was a highly potent pulmonary irritant and quickly filled enemy trenches due to it being a heavy gas. It is classified as a Schedule 3 substance under the Chemical Weapons Convention. In addition to its industrial production, small amounts occur from the breakdown and the combustion of organochlorine compounds, such as chloroform. Structure and basic properties Phosgene is a planar molecule as predicted by VSEPR theory. The C=O distance is 1.18 Å, the C−Cl distance is 1.74 Å and the Cl−C−Cl angle is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorine
Chlorine is a chemical element with the symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine is a yellow-green gas at room temperature. It is an extremely reactive element and a strong oxidising agent: among the elements, it has the highest electron affinity and the third-highest electronegativity on the revised Pauling scale, behind only oxygen and fluorine. Chlorine played an important role in the experiments conducted by medieval alchemists, which commonly involved the heating of chloride salts like ammonium chloride ( sal ammoniac) and sodium chloride (common salt), producing various chemical substances containing chlorine such as hydrogen chloride, mercury(II) chloride (corrosive sublimate), and hydrochloric acid (in the form of ). However, the nature of free chlorine gas as a separate substance was only recognised aroun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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