Detector paint

Other products of Porton Down s research and development at the end of the 1930s included eye shields to protect against high-altitude liquid mustard gas attack, the oil-skin anti-gas cape, impregnated battle dress, protective dubbing for boots, detectors and detector paints, decontamination procedures, gas identification sets for service units, respirators and anti-gas covers for horses and dogs. Protection for camels was also studied a prototype respirator still exists in the establishment at Porton Down. 

The CWS also studied the critical need for chemical agent detectors and alarms. Initially, World War I soldiers relied on their own senses (smell, and throat and nose irritation) to detect chemicals. Eventually, the CWS was able to produce various dyes that changed color when contaminated with mustard agent. Most of the formulas for the detector paints, however, were British, and the CWS had trouble duplicating their work.35... 

For droplets, the M5 detector paint and the M6 detector paper both turned from olive green to red. None of the detectors provided any advance warning, and all merely confirmed the presence of the agents after the fact. 

By March 1942 a number of blister gas detectors, all of which were based on color changes in a dye base and had their origins in British and American developments in 1918, had been standardized. They included the M4 vapor detector kit, capable of registering even faint concentrations of nitrogen and sulphur mustards M5 liquid vesicant detector paint M6 liquid vesicant detector paper and M7 vesicant detector crayon, sensitive to mustard and lewisite. Although the CWS had not discovered a better dye base than that developed by the British, NDRC chemists at the University of Chicago, at the University of Virginia, and at Ohio State improved its composition and developed new detector materials. ... 

Traditional appHcations for latices are adhesives, binders for fibers and particulate matter, protective and decorative coatings (qv), dipped goods, foam, paper coatings, backings for carpet and upholstery, modifiers for bitumens and concrete, and thread and textile modifiers. More recent appHcations include biomedical appHcations as protein immobilizers, visual detectors in immunoassays (qv), as release agents, in electronic appHcations as photoresists for circuit boards, in batteries (qv), conductive paint, copy machines, and as key components in molecular electronic devices. 

The reduction of molybdate salts in acidic solutions leads to the formation of the molybdenum blues (9). Reductants include dithionite, staimous ion, hydrazine, and ascorbate. The molybdenum blues are mixed-valence compounds where the blue color presumably arises from the intervalence Mo(V) — Mo(VI) electronic transition. These can be viewed as intermediate members of the class of mixed oxy hydroxides the end members of which are Mo(VI)02 and Mo(V)0(OH)2 [27845-91-6]. MoO and Mo(VI) solutions have been used as effective detectors of reductants because formation of the blue color can be monitored spectrophotometrically. The nonprotonic oxides of average oxidation state between V and VI are the molybdenum bronzes, known for their metallic luster and used in the formulation of bronze paints (see Paint). 

For the examination of paint films or special coatings, e.g. pipe linings, low-voltage holiday detectors with wet sponge electrodes are available. 

A combination of HPLC and amperometric detection was proposed for determination of tributylstannyl oxide in antifouling paint. The detector is of the static hanging Hg drop type in a flow cell, the solvent is CH2CI2/THF, containing tetrabutylammonium perchlorate as supporting electrolyte. The oxidation mechanism depicted in reactions 4... 

Some of the systems can be strung as a line device and offers detection over a long path alternatively they be used as spot detectors. A common deficiency after installation is they tend to become painted over, susceptible to damage, or the fusible element may suffer a change in activation temperature over a long installation period. 

The activity of chemically active AF paints usually relies on the reactivity of organometallic compounds (e.g. TBT-, Zn-, Si, Cu- acrylates and Zn-resinates) and inorganic pigments (i.e. CU2O). In spite of this, scanning electron microscopy coupled with energy dispersive X-ray detectors (SEM-EDX) has not been used extensively to characterise such reactions. Bishop and Silva... 

Grimmer G et al Characterization of polycyclic aromatic hydrocarbons as essential carcinogenic constituents of coal combustion and automobile exhaust using mouse-skin-painting as a carcinogen-specific detector. Toxicol Environ Chem 6 97, 1983... 

The measurement electrodes can be wrapped around, threaded onto, or painted over a standard capillary. The use of a grounded shield in between the measurement electrodes greatly reduces stray capacitance. (B) Simplified circuit diagram for a contactless conductivity detector. includes double layer capacitance Cjj as well as the capacitance across the capillary wall. 

This is the kind of information that one may obtain, using the detector without sampling of a painting. Figure 15 shows the setup for analyzing a painting in which a tan ribbon is aligned with the center of the detector. The spectrum obtained is shown at the bottom and is that of a typical natural yellow ochre. 

Most of the routine work in structural analysis is performed with D5000 Siemens diffractometer equipped with a Gobel mirror and an energy-dispersive detector. Raman micro-spectrometry has been recently introduced with a Labram infinity spectrometer with two laser sources, fitted with a horizontal output adapted to the investigation of vertical items like paintings or statues. For the most fine structural investigations, experiments are conducted with EXAFS, XANES or diffraction lines from various synchrotron facilities (ESRF at Grenoble, BESSY at Berlin, LURE at Paris). 

FIGURE 2-17. Contribution of molecular weight to polymer properties, (a) Molecular weight distribution profile of a typical polymer. (b) Quality control of an alkyd resin. It was determined that a good paint resulted only when the ratio of the peak heights was between 0.6 and 0.8. Detector refractive index. 

The components assembled at Winterthur in 1970 to make up the energy dispersive x-ray fluorescence analyzer system employed in this study of trace elements in paper, documents, prints, and watercolor paintings were Kevex Series 3000P cryogenic system and detector (sample viewing diameter, 15 mm detector resolution, 170 eV at 5.9 keV... 

Emitted by heavy atoms, such as uranium, radium, radon, and plutonium (to name a few), alpha particles are helium nuclei, making them the most massive kind of radiation. Alpha radiation can cause a great deal of damage to the living cells it encounters, but has such a short range in tissue (only a few microns) that external alpha radiation cannot penetrate the dead cells of the epidermis to irradiate the living cells beneath. If inhaled, swallowed, or introduced into open wounds, however, alpha radiation can be very damaging. In nature, alpha radiation is found in rocks and soils as part of the minerals, in air as radon gas, and dissolved in water as radium, uranium, or radon. Alpha emitters are also found in nuclear power plants, nuclear weapons, some luminous paints (radium may be used for this), smoke detectors, and some consumer products. Objects and patients exposed to alpha radiation may become contaminated, but they do not become radioactive. 

IR spectra were taken at room temperature (300 K) and liquid-helium temperatures (5-15 K), using a Bomem DAS Fourier transform infrared (FTIR) spectrometer and an InSb detector. For the low-temperature measurements, a Janis continuous-flow liquid-helium cryostat with wedged, IR-transparent windows was utilized. Hall-effect measurements, in the Van der Pauw geometry, were performed at room temperature using a system from MMR Technologies. Wires were attached to the ZnO using silver paint, which provided adequate Ohmic contacts for the electron concentrations (10 cm ) in these samples. 

Use of additional temperature detectors to provide highly localized and redundant temperature monitoring. These include detectors on the wall of the vessel skin thermocouples) as well as in thermowells exposed to the process fluids. In some cases, temperature-sensitive paint that changes color above a certain threshold is used on the outside of the vessel. 

MAJOR PRODUCT APPLICATIONS adhesives, caulks, sealants, inks, paints, coatings, EMI control, gaskets, decoration, plating, composites, building products, computers, pastes for electronics, stucco, arts and crafts, smoke detectors, covers, printers, copiers... 

Early CWA detectors were quite primitive and included primarily chemical-reactive dyes in paints. These were insensitive and therefore unreliable (Smart, 1997). Later technology used more sensitive chemical dyes in other formats such as paper tickets. Modem detectors now consist of fieldable IR spectrometers and an alarm system designed to warn of the presence of CWAs on the battlefield or in an enclosed space. Several rehable tests for the diagnosis of CWA exposure have been developed. To detect HD exposure, the level of thiodiglycol, a metabolite of HD, is quantitated in the urine using a gas chromatography/mass spectrometry (GC/MS) analytical method (Jakubowski et al., 1990 TB MED 296, 1996). Nerve agent exposure is detected in the field by the use of a fieldable Ellman assay to determine chohnesterase inhibition in the blood (Ellman et al., 1961 TB MED 296, 1996). 

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