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Pressure measurement in combusting and non-combusting gases using laser-induced grating spectroscopy
摘要： The measurement of pressure using laser-induced thermal grating spectroscopy, LITGS, with improved accuracy and precision is reported. Pressure values are derived from the record of the time-profile of LITGS signals by fitting of modelled signals to experimental data. The procedure is described for accurate modelling of the LIGS signals involving a sequence of calculation steps with appropriate weighting and calibration to determine the best-fit value of pressure-dependent parameters for averaged and single-shot measurements. Results are reported showing application of this model-fitting method to measurements of pressure in static cells using LITGS generated from NO in mixtures containing N2 at pressures in the range 0.5–5.0 bar with accuracy of 1–3% and single-shot precision of 4–7%. Time-resolved measurements of pressure, using LITGS signals generated in toluene-seeded fuel vapour, during the compression and expansion strokes of a motored optically accessible engine are reported with pressure-dependent accuracy ranging from better than 10 to around 20% over the cycle and single-shot precision in the range 5–15% over the same range. Measurements in the engine under firing conditions were obtained over a limited range and slightly increased uncertainties associated with varying composition resulting from exhaust gas residuals. The method was found to be of limited utility for measurements in high temperature flames at around ambient pressures.
关键词： Combustion,Laser-induced thermal grating spectroscopy,Non-combusting gases,Pressure measurement,LITGS
更新于2025-11-25 10:30:42
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Adsorption of hazardous gases in nuclear islands on monolayer MoS2 sheet
摘要： Monitoring and removing the hazardous gases (such as radioactive gases and hydrogen) in the nuclear islands are full with enormous challenges, although the two methods can improve the safety level of the nuclear power plant. Due to its excellent electronic and chemical properties, two dimensional materials are considered as the candidate for monitoring and removing the hazardous gases in the nuclear islands. In this paper, the adsorption of the hazardous gases on monolayer MoS2 sheet was investigated by using the first principles calculation method. The adsorption energy, total charge transfer, and density of states (DOS) were calculated to understand the adsorption mechanism and sensing performance of the monolayer MoS2 sheet to the hazardous gases. The results show that an attractive interaction exists between the hazardous gases and the monolayer MoS2 sheet. The magnitude of the adsorption energy demonstrates that physisorption dominates the adsorption of the hazardous gas molecules on the monolayer MoS2 sheet, but the adsorption of the dissociated H/I atom belongs to chemisorption. The DOS shows that the orbitals, H 1s and I 5p, play a crucial role in the adsorption, and the change of the electronic structure indicates that the monolayer MoS2 sheet might be a promising material which is used for monitoring the gaseous radioactive iodine in the nuclear islands.
关键词： Hydrogen,Hazardous gases,Radioactive gases,First principles calculation,Monolayer MoS2 sheet
更新于2025-09-23 15:23:52
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Light-illumination stability of amorphous InGaZnO thin film transistors in oxygen and moisture ambience
摘要： The light-illumination stability of amorphous InGaZnO Thin Film Transistors (a-IGZO TFTs) in oxygen and moisture ambience was in-depth characterized by both current-voltage (I-V) and capacitance-voltage (C-V) measurements. With the illuminated light wavelength decreasing, both I-V and C-V curves shifted negatively. When the ambient oxygen content or moisture level increased, the a-IGZO TFTs exhibited more stable properties under light illumination. A qualitative model was proposed to explain the related physical mechanism. The higher oxygen content or moisture level bene?ted the light-illumination-induced oxygen adsorption at back channels of a-IGZO TFTs and prevented the formation of oxygen vacancies (VO) in channel layers; the VO variation with the light illumination became more di?cult and hence led to better light-illumination stability of the corresponding TFT devices.
关键词： Thin ?lm transistor,Light-illumination stability,Amorphous InGaZnO,Ambient gases
更新于2025-09-23 15:23:52
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[IEEE 2018 International Conference on Applied Engineering (ICAE) - Batam, Indonesia (2018.10.3-2018.10.4)] 2018 International Conference on Applied Engineering (ICAE) - An Integrated Comparative Approach to Estimating Forest Aboveground Carbon Stock Using Advanced Remote Sensing Technologies
摘要： Greenhouse gases in the atmosphere play a very important role in maintaining the temperature of the earth. Plants absorb carbon in the atmosphere in the form of CO2 which is beneficial for photosynthesis which will produce O2 into the atmosphere. By utilizing remote sensing technology and field data integration, this research aims to estimating aboveground carbon reserves in the research area. The results of this research indicate that the above ground carbon stock resulting from estimation calculations using remote sensing data and field calculations using brown allometric are 103,397 TonC / Ha with an error rate of 1,8354. This error level indicates the size of the error in the estimated value of each pixel.
关键词： Carbon Stock,Batam Island,Temperature,Remote Sensing Data,Greenhouse Gases
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE Sciences and Humanities International Research Conference (SHIRCON) - Lima, Peru (2018.11.20-2018.11.22)] 2018 IEEE Sciences and Humanities International Research Conference (SHIRCON) - Low Cost Air Quality Measurement System Using Light Scattering Sensors
摘要： Air pollution is a very sensitive issue since currently, Lima is one of the places where there is greater air pollution by particulate matter in the world (PM10). Resulting in long-term health problems, especially in the respiratory and cardiovascular system that is why analyzing and knowing the quality of the air that we breathe, it is essential to prevent health problems in the future. Therefore, this research proposes an air quality measurement system based on Arduino and low-cost sensors that will provide us with a low-cost tool to determine the quality of the air we breathe. This system focuses on a matrix of sensors that will monitor the temperature and humidity conditions, as well as gases harmful to our health and PM10. Finally, these measured values will be reflected in an LCD revealing the values in real time.
关键词： particulate matter,light scattering sensor,polluting gases,Arduino
更新于2025-09-23 15:22:29
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Carbon Dioxide and Water Vapour Fluxes of a Alkaline Fen and Their Dependence on Reflectance
摘要： This study shows results of parallel measurements of greenhouse gases fluxes (carbon dioxide and water vapour) and canopy reflectance of alkaline fen. Fluxes were measured using eddy-covariance technique on micrometeorological station located in the Upper Biebrza Basin (NE Poland) in Rogo?ynek Village. Study site is located in the Biebrza National Park which was established to protect one of the biggest coherent lowland wetland area in the Central Europe. Statistical relations of reflectance and spectral indices with fluxes were calculated based on measurements during two growing season (2015 and 2016). Four types of functions were examined: linear, quadratic, exponential and logarithmic and for two timestamps: half-hour and day. The correlation between carbon dioxide fluxes and reflectance is better than for water vapour fluxes. For both carbon dioxide and water vapour we obtained higher correlations coefficients using selected spectral indices than using reflectance and higher correlations for daily timestamp than for half-hour fluxes.
关键词： greenhouse gases,eddy-covariance technique,spectral indices,Biebrza River valley,wetland
更新于2025-09-23 15:22:29
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[IEEE 2018 International Conference on Emerging Trends and Innovations In Engineering And Technological Research (ICETIETR) - Ernakulam (2018.7.11-2018.7.13)] 2018 International Conference on Emerging Trends and Innovations In Engineering And Technological Research (ICETIETR) - Design, Simulation and Optimization of Metal Oxide Sensor for Ammonia Detection Using Nanowires
摘要： The levels of toxic gases are increasing enormously in the atmosphere, thereby causing adverse effects on the health of all living beings. There are various toxic gases like ammonia, oxides of nitrogen etc., which have to be detected and eliminated even if present in minute concentrations. Metal oxide based sensors is a sought-after technology for various reasons. In this paper, we present a method of detecting ammonia gas using titanium oxide nanowire based gas sensor. The basic principle of operation was adsorption of gas on to the sensing substance. This happens only at elevated temperatures which are provided by a micro hotplate. The aim was to increase the sensitivity of the sensor and to reduce the power consumption. Surface resistance, which varies due to interactions of gas and oxide, was taken as a measure to calculate the concentration in the ambience of sensor. COMSOL multiphysics tool was used for the performance analysis of the sensor.
关键词： metal oxide,COMSOL,nanowire,micro hotplate,toxic gases
更新于2025-09-23 15:22:29
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Near-infrared remote sensing of Los Angeles trace gas distributions from a mountaintop site
摘要： The Los Angeles basin is a significant anthropogenic source of major greenhouse gases (CO2 and CH4) and the pollutant CO, contributing significantly to regional and global climate change. We present a novel approach for monitoring the spatial and temporal distributions of greenhouse gases in the Los Angeles basin using a high-resolution spectroscopic remote sensing technique. A new Fourier transform spectrometer called CLARS-FTS has been deployed since May, 2010, at Jet Propulsion Laboratory (JPL)'s California Laboratory for Atmospheric Remote Sensing (CLARS) on Mt. Wilson, California, for automated long-term measurements of greenhouse gases. The instrument design and performance of CLARS-FTS are presented. From its mountaintop location at an altitude of 1673 m, the instrument points at a programmed sequence of ground target locations in the Los Angeles basin, recording spectra of reflected near-IR solar radiation. Column-averaged dry-air mole fractions of greenhouse gases (XGHG) including XCO2, XCH4, and XCO are retrieved several times per day for each target. Spectra from a local Spectralon? scattering plate are also recorded to determine background (free tropospheric) column abundances above the site. Comparisons between measurements from LA basin targets and the Spectralon? plate provide estimates of the boundary layer partial column abundances of the measured species. Algorithms are described for transforming the measured interferograms into spectra, and for deriving column abundances from the spectra along with estimates of the measurement precision and accuracy. The CLARS GHG measurements provide a means to infer relative, and possibly absolute, GHG emissions.
关键词： column abundances,remote sensing,greenhouse gases,Fourier transform spectrometer,Los Angeles basin
更新于2025-09-23 15:22:29
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Initial evaluation of proportional scintillation in liquid Xenon for direct dark matter detection
摘要： The Liquid Xenon Time Projection Chamber (LXeTPC) is often seen as an ideal detector for the direct Dark Matter (DM) search. In such experiments an efficient γ-ray background discrimination is essential. This can be achieved by distinguishing the ionization density, different for γ-rays and Nuclear Recoils. Two quantities are used for this measurement, the direct scintillation light generated by the ionizing event, and the free charges swept away by an electric field before recombination occurs. Present LXe detectors apply the Dual Phase principle, i.e. the charges are extracted into the gas phase and are measured by the proportional light they produce in a strong electric field in the gas. With ever growing dimensions of the detectors it is difficult to meet the tight mechanical tolerances required. Proportional scintillation also occurs in the liquid phase, although at much higher field strengths. Such field strengths can be reached in the 1/r field close to thin wires. All the limitations due to the extraction of electrons into the gas phase are avoided. Since the liquid level has not to be crossed, the design of the detector becomes simpler with many advantages over Dual Phase detectors. Our initial tests clearly show the pulses. They are much shorter, and their length is limited by longitudinal diffusion of the drifting charges. The threshold for proportional light production seems significantly lower, and estimates of the gain are more favorable than previously predicted. We attribute these discrepancies to our improved liquid purity.
关键词： Time projection Chambers (TPC),Dark Matter detectors (WIMPs,multiplication and electroluminescence in rare gases and liquids,ionization,Charge transport,double-phase),axions,etc.),Noble liquid detectors (scintillation
更新于2025-09-23 15:22:29
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Simple imaging for the diamond anvil cell: Applications to hard-to-reach places
摘要： The employment of high-pressure gases as a pressure-transmitting medium, sample, or reactant for diamond anvil cell experiments is widespread. As a pressure transmitter, high-pressure gases are crucial to forming quasi-hydrostatic compression atmospheres for samples inside the uniaxially driven cell. We describe an optical design for forming high-resolution images of the gasket and sample chamber of the diamond anvil cell under high gas pressures in a gas loading apparatus. Our design is simple, is of low-cost, and may be easily adapted to suit gas loading apparatus of any design, as well as other common hard-to-reach environments in diamond anvil cell experiments, i.e., those with large stand-off distances, such as cryostats.
关键词： optical design,high-pressure gases,gas loading apparatus,diamond anvil cell,imaging
更新于2025-09-23 15:21:21