A gas leak detection system that combines sensor units having an array of sensors that detect natural gas and the volatile organic compounds and variable atmospheric conditions that confound existing gas leak detection methods, a specially designed sensor housing that limits the variability of those atmospheric conditions, and a machine learning-enabled process that uses the wide array of sensor data to differentiate between natural gas leaks and other confounding factors. Multiple low-cost sensor units can be used to monitor gas concentrations at multiple locations across a site (e.g., a well pad or other oil or natural gas facility), enabling the gas leak detection system to model gas leak emission rates in two- or three-dimensional space to reveal the most likely origin of the gas leak.

The present disclosure provides a method for preparing nitrogen oxide gas sensor based on sulfur-doped graphene. The method includes: 1) providing graphene and a micro heater platform substrate, and transferring the graphene onto the micro heater platform substrate; 2) putting the micro heater platform substrate covered with the graphene into a chemical vapor deposition reaction furnace; 3) performing gas feeding and exhausting treatment to the reaction furnace by using inert gas; 4) simultaneously feeding inert gas and hydrogen gas into the reaction furnace at a first temperature; 5) feeding inert gas, hydrogen gas and sulfur source gas into the reaction furnace at a second temperature for reaction to perform sulfur doping to the graphene (21); and 6) stopping feeding the sulfur source gas, and performing cooling in a hydrogen gas and insert gas shielding atmosphere.

A sensor is disclosed. The sensor according to an embodiment of the present invention may include a substrate; a first electrode pattern disposed on one side of the substrate to form a layer; a second electrode pattern disposed on the one side of the substrate to form a layer and separated from the first electrode pattern; a sensing layer located on the one side of the substrate and covering the first electrode pattern and the second electrode pattern and containing a semiconductor; a protective layer located on the one side of the substrate and covering at least a part of the sensing layer, and containing a material different from that of the sensing layer; a first electrode pad disposed on the one side of the substrate to form a layer and electrically connected to the first electrode pattern; a second electrode pad disposed on the one side of the substrate and electrically connected to the second electrode pattern; and a housing accommodating the substrate and including a filter spaced apart from the substrate, wherein the substrate includes an opening formed adjacent to an outer boundary of the first and second electrode patterns.

Detection and capture of toxic nitrogen oxides (NO.sub.x) is important for emissions control of exhaust gases and general public health. The low power sensor provides direct electrically detection of trace (0.5-5 ppm) NO.sub.2 at relatively low temperatures (50° C.) via changes in the electrical properties of nitrogen-oxide-capture active materials. For example, the high impedance of MOF-74 enables applications requiring a near-zero power sensor or dosimeter, such as for smart industrial systems and the internet of things, with 0.8 mg MOF-74 active material drawing <15 pW for a macroscale sensor 35 mm.sup.2 area.

There is described a system for analyzing an air condition. The system comprises a detection unit configured for detecting of detection signals indicative of a bacteria-related contamination of an evaporator and/or an air filter of the air condition, an analyzing unit configured for analyzing of a level of contamination of the evaporator and/or the air filter based on the detection signals, and an output unit configured for outputting the analyzed level of contamination of the evaporator and/or the air filter to a user.

Various apparatus, systems, and methods for measuring a solution characteristic of a sample comprising microorganisms are disclosed. In one embodiment, a sensor apparatus is disclosed comprising a sample container comprising a sample chamber configured to receive the sample and a reference sensor component comprising a reference conduit having a reference conduit cavity defined therein. The reference conduit cavity can be at least partially filled with a reference buffer gel, buffer solution, or wicking component. A segment of the reference conduit can extend into the sample chamber. A reference electrode material can be positioned at a proximal end of the wicking component or extend partially into the reference conduit cavity. The sensor apparatus can also comprise an active sensor component having an active electrode in fluid contact with the sample. The sample in the sample chamber can be aerated through an aeration port defined along a surface of the sample container.

A gas sensing device is provided. The gas sensing device includes a substrate, a sensing film deposited on the substrate, and a plurality of electrodes deposited on the sensing film. The sensing film comprising ReNiO3, wherein Re is a rare-earth cation wherein. At least one of the electrodes including platinum, palladium, or a combination thereof. The electrodes are spaced apart from each other for measurement of electrical resistance.

A gas sensor for sensing a gas in a humid environment includes a first electrode layer, a second electrode layer that is spaced apart from the first electrode layer, and a gas sensing layer that electrically interconnects the first electrode layer and the second electrode layer. The gas sensing layer is made of a hygroscopic electrically insulating material.

Disclosed is a composition for a hydrogen sulfide gas sensor containing copper, lithium and NiWO.sub.4, wherein the NiWO.sub.4 is co-doped with the copper and the lithium. Also disclosed is a method for preparing a composition for a hydrogen sulfide gas sensor, the method including steps of: (1) mixing NiO, Li.sub.2CO.sub.3, CuO and WO.sub.3 powders together at a molar ratio of 0.720 to 0.725:1.0 to 1.05:0.0120 to 0.0125:0.25 to 0.255, followed by calcination, thus preparing a powder mixture; (2) applying pressure to the powder mixture by a cold isostatic pressing process, thus preparing a green body; and (3) subjecting the green body to normal-pressure sintering.

A sensing material for detecting hydrogen sulfide capable of detecting hydrogen sulfide even having a low concentration, a hydrogen sulfide-sensitive layer containing the sensing material for detecting hydrogen sulfide, and a metal oxide semiconductor-type gas sensor having the hydrogen sulfide-sensitive layer are provided. The sensing material for detecting hydrogen sulfide includes CuFe.sub.2O.sub.4-type complex oxide (W). The CuFe.sub.2O.sub.4-type complex oxide (W) contains, as a main component (W1), 35.0 to 49.5 mol % of iron oxide in terms of Fe.sub.2O.sub.3 and 50.5 to 65 mol % of copper oxide in terms of CuO, and an average particle diameter of particles is 3 μm or less.