The invention relates to a colorimetric gas detector for determining and monitoring gaseous substances. The colorimetric gas detector can be used in any application requiring the detection of substances in a gaseous environment. The colorimetric gas detector has a photodetector, a light source positioned opposite to the photodetector, and a receiving slot for positioning a colorimetric media between the camera and the light source.

Disclosed is a gas sensor element having an electrode containing a first metal as a predominant component and a lead containing a second metal as a predominant component. The electrode and the lead are connected directly at a connection boundary thereof, or connected indirectly via a connection joint. The connection boundary or joint includes a component region where either one of the first and second metals lower in specific gravity than the other of the first and second metals is contained in an amount ranging between those in the electrode and the lead.

A gas detection sheet wherein a porous coordination polymer represented by formula (1) is supported on a supporter and the air permeability of the gas detection sheet is 0.8 seconds or more and 60 seconds or less.

Fe.sub.x(pz)[Ni.sub.1-yM.sub.y(CN).sub.4]  (1)

(wherein, pz=pyrazine, 0.95≦x<1.05, M=Pd or Pt, 0≦y<0.15).

An ammonia detection section is disposed on an electrically insulating layer and includes a reference electrode, a solid electrolyte body for ammonia, and a detection electrode that are stacked in this order on the electrically insulating layer. In the ammonia detection section, a three-phase boundary is formed at the interface between the reference electrode and the solid electrolyte body for ammonia, and another three-phase boundary is formed at the interface between the detection electrode and the solid electrolyte body for ammonia. The concentration of ammonia in exhaust gas is thereby detected. The ammonia detection section includes a porous layer formed of an electrically insulating porous material and disposed between the insulating layer and the reference electrode.

A chemosensing hydrogel is provided that undergoes a colorimetric reaction in response to the detection of a biogenic amine vapor, such as a biogenic amine vapor that is a by-product resulting from food spoilage. In an embodiment, an apparatus for detection of biogenic amines, is provided that includes a hydrogel having a bimetallic iron(II)-iron(III) complex disposed within the hydrogel, wherein the hydrogel is configured to change from a first color to a second color in response to exposure to a biogenic amine.

A method and system for mitigating a urea deposit within an SCR system that includes determining a mass of an accumulated urea deposit present within the SCR catalyst and SCR piping, comparing the mass of the accumulated urea deposit with a deposit upper threshold limit, and initiating an SCR regeneration event when the mass of the accumulated urea deposit is greater than the deposit upper threshold limit. The method further includes determining an amount of NH.sub.3 passing through the SCR catalyst downstream of the urea deposit, comparing the amount of NH.sub.3 passing through the SCR catalyst with an NH.sub.3 regeneration threshold limit, and terminating the SCR regeneration event when the level of NH.sub.3 passing through the SCR catalyst is less than the SCR NH.sub.3 regeneration threshold.

A gas sensor, and a method for measuring the concentrations of a plurality of target components in a gas to be measured are disclosed. The gas sensor is provided with: a specific component measurement means which measures the concentration of a specific component in a measurement chamber; a preliminary oxygen concentration control means which controls the oxygen concentration in a preliminary adjustment chamber; a drive control means which controls the driving and stopping of the preliminary oxygen concentration control means; and a target component acquisition means which, on the basis of the difference between sensor outputs from the specific component measurement means when the preliminary oxygen concentration control means is being driven and when the preliminary oxygen concentration control means is stopped, and one of the respective sensor outputs, acquires the concentrations of a first target component and a second target component.

A gas sensor device includes: a sensor film including a sensor surface and a resistance which increases with an increase in an amount of gas adsorbed on the sensor surface; a first electrode, a second electrode, and a third electrode that are electrically coupled to the sensor film; and a protective film that covers the sensor surface in a region between the first electrode and the second electrode, wherein the sensor surface is exposed in a region near the third electrode.

Systems, devices, and methods for a gas sensor comprising one or more optical cells; a processor having addressable memory, the processor configured to: detect gas from the one or more optical cells of the gas sensor, where the detected gas is one or more of: methane, carbon dioxide, hydrogen sulfide, water, ammonia, sulfur oxides, and nitrogen; record data corresponding to the detected gas, where the recorded data comprises at least one of: an ambient temperature from a temperature sensor, an ambient pressure from a pressure sensor, an aerial vehicle telemetry, and an aerial vehicle location from a global positioning system (GPS); and generate a map of atmospheric greenhouse gas concentration on a map based on the detected gas and the recorded data.

A system for detecting molecular structures is provided. The system includes a radio frequency (RF) wireless antenna, batteryless sensor, and a network analyzer. The sensor has an ultra-high frequency dipole antenna that transmits data to the RF wireless antenna and a sensing element. The sensing element is operatively coupled to the dipolar antenna and detects molecular structures. The network analyzer receives data from the RF wireless antenna and analyzes the data to determine a concentration of molecular structures.