Processes for sensing a variety of toxic chemicals and/or processes for determining the residual life of a filter or filtration system are provided. Exemplary process for sensing a toxic chemical include contacting a toxic chemical, or byproduct thereof, with a sorbent that includes a porous metal hydroxide and a transition metal reactant suitable to react with a toxic chemical or byproduct thereof. The sorbent is contacted with the toxic chemical or byproduct thereof for a sampling time. A difference between a post-exposure colorimetric state of the sorbent and a pre-exposure colorimetric state of the sorbent or control is determined to thereby sense exposure to, or the presence of, the toxic chemical or byproduct thereof.

The disclosure includes an air quantity analyzer for use in underground coal mines, comprising an explosion-proof enclosure. According to some embodiments, the air quantity analyzer for use in underground coal mines comprises a gas pipeline inside of the explosion-proof enclosure, the gas pipeline coupled to a mechanical component selected from the group consisting of an air sampler, a gas pool, and combinations thereof, a detection device inside of the explosion-proof enclosure, the detection device having a vacuum pump, wherein the vacuum pump is coupled to the gas pipeline, and a central processor inside of the explosion-proof enclosure and electrically coupled to the vacuum pump of the detection device, the central processor electrically coupled to an electric component selected from the group consisting of a light source, a detector, a power conversion module, a display and alarm module, a data communication module, and combinations thereof.

A sensor and method for the rapid detection of fluoride containing gaseous species specifically the chemical warfare agents Sarin and Soman nerve gas, in which a chemically sensitive composition containing dye indicator molecules complexed with a heavy metal salt is exposed to an environment under surveillance for toxic gasses. In one embodiment the sensing composition is introduced into a polymer-based substrate. The detection composition reacts with hydrogen fluoride which is a decomposition by-product of Sarin and Soman gas so as to change the color of the dye indicator, in one embodiment being pentamethoxy red, that is to change the color of the polymer-based substrate from colorless to a dark purple color. The complex of pentamethoxy red with the exemplary heavy metal salt, zirconyl chloride, is specific for Sarin and Soman nerve gas; it does not react to certain other toxic gases. In various embodiments a hydrolyzing agent is introduced in the polymer-based substrate to improve the detection reaction sensitivity and to increase the reaction rate and decrease the detection time for sensor chemistry.

A method for measuring the concentration of fluorine gas, which includes irradiating a halogen fluoride-containing gas with ultraviolet light in which the ratio (W.sub.X/W.sub.F) of the maximum value (W.sub.X) of ultraviolet light intensity in the wavelength region of less than 250 nm with respect to the ultraviolet light intensity (W.sub.F) at a wavelength of 285 nm is 1/10 or less, and measuring the absorbance at a wavelength of 285 nm to obtain the concentration of fluorine gas contained in the halogen fluoride-containing gas.

New alloys of Group VI transition metal dichalcogenides having the chemical formula MX.sub.2-xX.sub.x, produced using a chalcogen-substitution approach, wherein M is a Group VI transition metal (Cr, Mo, W, or Sg); X is a chalcogen (O, S, Se, Te, or Po); and X is a group 15 (N, P, As, Sb, or Bi) or a group 17 (F. Cl, Br, I, or At); and where x ranges from 0 to 2. The stability of different structural phases of such MX.sub.2-xX.sub.x Group VI 2D TMD alloy materials can be tuned via the choice of the chalcogen used. The MX.sub.2-xX.sub.x Group VI 2D TMD alloy materials produced in accordance with the chalcogen-substitution approach of the present invention can be used as components of phase-change based devices such as memory elements, field-effect transistors (FETs), or gas sensors.

The present invention provides a catalytic conversion-type sensor that detects a detection target gas by detecting a conversion gas produced through a reaction, the catalytic conversion-type sensor including: a gas flow path that allows the detection target gas to flow down; and a conversion portion that is connected to the gas flow path, the conversion portion including, on a side partitioned by a diffusion means that allows the detection target gas to naturally diffuse, a heated catalyst portion that produces a conversion gas by causing the detection target gas to come into contact with a heated catalyst and react with the heated catalyst, and a sensor element portion that is capable of detecting the conversion gas produced through the reaction.

Systems and methods for sanitizing pool and spa water are provided. An electrolytic chlorinator is provided which includes a combined flow, temperature, and salt concentration sensor. The electrolytic chlorinator could include an acid tank for in-situ cleaning of the electrolytic chlorinator or acidification of pool/spa water where needed. A delayed polarity reversal technique is provided for de-scaling and managing passivation of the blades of an electrolytic chlorinator. The electrolytic chlorinator could include a sacrificial anode for protecting components of the chlorinator as well as other pool/spa components. The electrolytic chlorinator could include an integral, electrically-controlled acid generator, a brine tank for periodically superchlorinating and/or shocking pool/spa water, and/or a plurality of chemical tanks/feeds for periodically injecting chemicals into the chlorinator. A combined ultraviolet (UV)/Ozone and salt (electrolytic) chlorine generator is provided, as well as: filters having integral UV sanitizers; reflective linings for UV sanitization systems; means for injecting bubbles into pool/spa water; and a system for acquiring and analyzing samples of pool/spa water using an unmanned aircraft (drone).

The techniques described herein provide sensing systems and methods that provide configurable sensitivity and extended dynamic range of gas measurements. The systems and methods apply dielectric excitation at two or more excitation frequencies to a sensing material via sensing electrodes. A linearity of the electrical signal is changed by changing the operation parameters of the gas sensing element of the sensor.

An electrochemical gas sensor (10) includes a housing (11) which has a number of electrodes (31, 32), i.e. at least one working electrode (31) and at least one counter electrode (32), in addition to a liquid electrolyte (60). At least one of the electrodes (31, 32) and/or the housing (11) are at least partially formed of an absorption agent composition. A method of detecting acid gases employs the electrochemical gas sensor (10).

Processes for sensing a variety of toxic chemicals and/or processes for determining the residual life of a filter or filtration system are provided. Exemplary process for sensing a toxic chemical include contacting a toxic chemical, or byproduct thereof, with a sorbent that includes a porous metal hydroxide and a transition metal reactant suitable to react with a toxic chemical or byproduct thereof. The sorbent is contacted with the toxic chemical or byproduct thereof for a sampling time. A difference between a post-exposure colorimetric state of the sorbent and a pre-exposure colorimetric state of the sorbent or control is determined to thereby sense exposure to, or the presence of, the toxic chemical or byproduct thereof.