A method for regulating a gas mixture formed from a gas and a fuel gas in a fuel gas-operated heating appliance, wherein the gas mixture is created by providing and mixing a gas quantity by way of a first control element and a fuel gas quantity by way of a second control element, wherein a microthermal gas sensor and a gas mixture sensor are used and sensor signals are relayed to a controller, and wherein upon change in the detected sensor signal [of the] gas sensor the newly detected sensor signal of the gas sensor is compared to reference values which have been measured in the laboratory and saved in a table of values in the controller and from this a target value of the sensor signal of the gas mixture sensor is determined without a mixture ratio of the gas mixture composed of fuel gas and gas being changed.

A method is provided for estimating at least one combustion characteristic of a fuel gas belonging to a family of fuel gases, where the at least one characteristic includes at least one of a Wobbe index or a higher heating value. The method includes measuring at least two flow properties of the fuel gas and measuring a dihydrogen content X.sub.H.sub.2 contained in the fuel gas. The method also includes estimating the at least one characteristic

[00001]${}_{\frac{\mathrm{GN}}{H.Math..Math.2}}$

using an empirical affine relationship of

[00002]${}_{\frac{\mathrm{GN}}{H.Math..Math.2}}=+.Math.Y+.Math.X_{H_2}.$

Here, , , and are coefficients predetermined for the family of fuel gases, and Y is a variable representative of physical properties of the fuel gas prepared from the measurements of the at least two flow properties of the fuel gas.

The present disclosure relates to a portable hydrocarbon plume monitoring system. The system is configured to be supportable at an elevated location above a region to be monitored for the presence of a hydrocarbon plume. The system has a housing and a hyperspectral sensor supported from the housing. The hyperspectral sensor images at least a portion of the region to be monitored and detects a presence of a hydrocarbon plume emanating from the region. The system also includes a computer for controlling operation of the hyperspectral sensor. The computer is adapted to use absorbance information and data generated by the hyperspectral sensor to determine the presence of a hydrocarbon plume emanating from the region.

A method for the detection of adulterated gasoline in a sample is disclosed. The method includes contacting a sample with an immobilized molecular probe, the immobilized molecular probe having a photoluminescence which is environmentally sensitive; collecting the photoluminescence from the immobilized molecular probe; and determining whether the photoluminescence is indicative of adulterated gasoline. A test strip for the detection of adulterated gasoline in a sample is also disclosed, including an immobilized molecular probe embedded in a substrate and/or immobilized to the substrate, the immobilized molecular probe having photoluminescence which is environmentally sensitive to adulterated gasoline. The method and test strips are designed to be robust, portable, and within the capabilities of untrained personnel.

Disclosed are substance detection and identification devices, and methods of using them for detection and identification of substances in ambient surroundings, on surfaces of objects, inside closed items or in fluids. A substance detection and identification device may comprise a housing, an opening in the housing for passage of sample material therethrough, a sensing unit located in the housing and an array of sensing elements configured and operable to interact with sample material in the vicinity thereof for detecting one or more specific substances and generating sensing data indicative thereof. A sample path defined in the housing between the opening and the sensing unit is used for facilitating flow of the sample material towards the sensing unit. A gas inlet assembly provided in the housing is configured for providing a predetermined supply of the sample material to the sensing elements in the sensors array, to thereby enable a predetermined time pattern of the sensing data from the array of sensing elements. A heating unit may be provided in the housing for heating the sensing elements.

Methods, devices, and systems are provided for analyzing the moisture content in natural gas. In one embodiment, a portable moisture analyzer system is provided and can include a moisture analyzer and a housing. The moisture analyzer can include a tunable diode laser absorption spectrometer (TDLAS) and a natural gas sample conditioning system. The TDLAS can be configured to detect water vapor content within a natural gas sample. The sample conditioning system can be in fluid communication with the TDLAS and can be configured to condition at least one of temperature, flow rate, and pressure of a natural gas sample. The housing can be configured to receive the moisture analyzer therein and to protect the moisture analyzer from vibration and/or shock.

Methods and systems for testing performance of a catalyst element are provided. The catalyst element can be an oxidation catalyst element or a non-selective catalytic reduction catalyst element, where the subject methods and systems are configured for testing under various lambda () conditions. The subject methods and systems find use in a variety of applications where it is desired to test the performance of a catalyst element.

The invention determines at least one combustion property of a two-phase fuel gas. The invention comprises providing the fuel gas from substantially only a first phase of the fuel gas to a combustion engine and operating the combustion engine such that a first -value is achieved in the combustion process. The invention further provides the fuel gas from substantially only a second of the two phases of the fuel gas to the combustion engine, wherein the second phase is different from the first phase and wherein the same volumetric air/fuel ratio is kept as when the combustion engine was operated with the first -value. The invention determines a second -value when the combustion engine is operated with the fuel gas from substantially only the second of the two phases of the fuel gas and determines at least one first combustion property of the fuel gas based on the second -value.

A method includes providing a length of pipeline that has a housing defining a central bore extending the length of the pipe and a space formed within the housing and extending the length of the pipe. At least one condition within the space is continuously monitored within the space to detect in real time if a change in the housing occurs.

Systems and methods for evaluating permeability at unsteady-state pressure conditions and areal distribution of microproppants are provided. In some embodiments, the methods comprise: obtaining a first dataset relating to a positive permeability through a split core plug sample of a subterranean formation at a plurality of different differential pressures; obtaining a second dataset relating to a positive permeability through the split core plug sample at each different differential pressure after a plurality of microproppant particles have been placed between two halves of the sample; extrapolating a baseline positive permeability of the sample at a differential pressure equal to zero based on the first dataset; extrapolating a treated positive permeability of the sample at a differential pressure equal to zero based on the second dataset; calculating a closure resistance of the fracture and the fracture closure pressure using the second dataset; and estimating a proppant areal placement factor.