scholarly journals Ligand-Linked Nanoparticles-Based Hydrogen Gas Sensor with Excellent Homogeneous Temperature Field and a Comparative Stability Evaluation of Different Ligand-Linked Catalysts

Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1205 ◽  
Author(s):  
Anmona Pranti ◽  
Daniel Loof ◽  
Sebastian Kunz ◽  
Volkmar Zielasek ◽  
Marcus Bäumer ◽  
...  
Keyword(s):  
Temperature Field ◽  
Gas Flow ◽  
Hydrogen Gas ◽  
Sensor Design ◽  
Long Term Stability ◽  
Average Temperature ◽  
Improved Stability ◽  
Thermoelectric Sensor ◽  
Comparative Stability ◽  
Homogeneous Temperature

This paper presents a thermoelectric gas microsensor with improved stability where platinum nanoparticles linked by bifunctional ligands are used as a catalyst. The sensor design provides a homogeneous temperature field over the membrane, an important factor for the long-term stability of the catalyst. A comprehensive study of heat transfer from the chip is performed to evaluate the convection heat loss coefficient and to understand its effect on the homogeneity of the temperature field in a real-time situation. The effect of highly heat-conductive thermopiles is also analyzed by comparing the temperature distribution and power consumption with a thermoresistive sensor of the same dimensions and materials. Despite the thermopiles, the thermoelectric sensor gives better temperature homogeneity and consumes 23% less power than the thermoresistive sensor for 90 °C average temperature on the membrane. A comparative stability analysis among ligand-linked nanoparticles with 5 different ligands and unprotected nanoparticles was done through 3 consecutive 24 h tests under 1.5% continuous hydrogen gas flow. The sensors give very stable output, almost no degradation, through 72 h (3 × 24 h) tests for 3 different ligand-linked nanoparticles. The sensor design provides superb stability to the catalyst: Even catalysts of unprotected nanoparticles withstood more than 24 h and the sensor signal degradation is only 20%.

Experimental Study of Thermal Effects in a Hydrogen Cryo-Adsorption Storage System

2009 ◽  
Author(s):  
Petar Aleksic´ ◽  
Erling Næss
Keyword(s):  
Activated Carbon ◽  
Gas Flow ◽  
Hydrogen Adsorption ◽  
Storage System ◽  
Hydrogen Gas ◽  
Material Development ◽  
Average Temperature ◽  
Gas Compression ◽  
Charge Pressure ◽  
Main Barrier

While the main barrier for the development of hydrogen adsorption type storage systems remains the material development, an improved thermal management may offer solutions to minimize the penalties in the amount of stored gas during fast-filling and the residual amount of hydrogen during discharging operations. The emphasis of this work was to experimentally investigate the dynamical thermal behavior of a hydrogen cryoadsorption storage system during fast-filling operations. The experiments were conducted with granulated activated carbon and MOF adsorbents. The influence of the charge pressure and the gas flow rate on the temperature elevations and the amount of filled hydrogen gas was analyzed. The heat generated in the storage vessel originates from the released heat of adsorption, gas compression work and thermal energy transfer that takes place when high pressure gas at the ambient temperature is introduced to the tank. A typical average temperature increase observed during the charging of the test tank, filled with the activated carbon (NORIT R0.8 extra), to 2 MPa was about 21 K. Such temperature elevation leads to a significant decrease in adsorption storage capacity.

scholarly journals The Berkeley Earth Land/Ocean Temperature Record

2020 ◽  
Author(s):  
Robert A. Rohde ◽  
Zeke Hausfather
Keyword(s):  
Temperature Field ◽  
Sea Ice ◽  
The Arctic ◽  
Temperature Record ◽  
Ocean Temperature ◽  
Average Temperature ◽  
Ice Coverage ◽  
Air Temperatures ◽  
The 19Th Century ◽  
Homogeneous Temperature

Abstract. A global land/ocean temperature record has been created by combining the Berkeley Earth monthly land temperature field with spatially-kriged version of the HadSST3 dataset. This combined product spans the period from 1850 to present and covers the majority of the Earth's surface: approximately 57 % in 1850, 75 % in 1880, 95 % in 1960, and 99.9 % by 2015. It includes average temperatures in 1° × 1° lat/lon grid cells for each month when available. It agrees quite well with records from Hadley's HadCRUT4, NASA's GISTEMP, NOAA's GlobalTemp, and Cowtan and Way, but provides a more spatially complete and homogeneous temperature field. Two versions of the record are provided treating areas with sea ice cover as either air temperature over sea ice or sea surface temperature under sea ice. The choice of how to assess the temperature of areas with sea ice coverage has a notable impact on global anomalies over past decades due to rapid warming of air temperatures in the Arctic. Accounting for rapid warming of Arctic air suggests ~ 0.1 °C additional global-average temperature rise since the 19th century than temperature series that do not capture the changes in the Arctic. Updated versions of this dataset will be presented each month at the Berkeley Earth website (http://berkeleyearth.org/data/), and a convenience copy of the version discussed in this paper has been archived and is freely available at https://doi.org/10.5281/zenodo.3634713 (Rohde & Hausfather, 2020).

scholarly journals Evaluation of hydrogen gas flow system in DECY - 13 cyclotron

2021 ◽  
Vol 1825 (1) ◽  
pp. 012027
Author(s):  
F I Diah ◽  
Saminto ◽  
V A F Sari ◽  
K Wibowo ◽  
F S Permana
Keyword(s):  
Gas Flow ◽  
Flow System ◽  
Hydrogen Gas

scholarly journals Hydrogen gas concentration measurement in small area using raman lidar measurement technnology

2018 ◽  
Vol 176 ◽  
pp. 01019 ◽  
Author(s):  
Sachiyo Sugimoto ◽  
Ippei Asahi ◽  
Tatuso Shiina
Keyword(s):  
Small Area ◽  
Gas Flow ◽  
Hydrogen Gas ◽  
Measurement Technology ◽  
Lidar Measurement ◽  
Measurement Point ◽  
Raman Lidar ◽  
Gas Concentration ◽  
Scattering Light ◽  
Temporal And Spatial

When change of hydrogen(H2) gas concentration in a certain point is measured, non-contact measurement technology with high temporal and spatial resolution is necessary. In this study, H2 concentration in the small area of <1cm2 under the gas flow was measured by using a Raman lidar. Raman scattering light at the measurement point of 750mm ahead was detected by the Raman lidar. As a result, it was proved that the H2 concentration of more than 100ppm could be successfully measured.

Numerical Analysis of Flow Fields and Temperature Fields in a Regenerative Heating Furnace for Steel Pipes

2018 ◽  
Vol 10 (3) ◽  
Author(s):  
Yi Han ◽  
Feng Liu ◽  
Xin Ran
Keyword(s):  
Temperature Field ◽  
Flow Field ◽  
Flow Velocity ◽  
Gas Flow ◽  
Flow Fields ◽  
Heating Furnace ◽  
Temperature Fields ◽  
Turbulent Layer ◽  
Steel Pipes ◽  
Pipe Blanks

In the production process of large-diameter seamless steel pipes, the blank heating quality before roll piercing has an important effect on whether subsequently conforming piping is produced. Obtaining accurate pipe blank heating temperature fields is the basis for establishing and optimizing a seamless pipe heating schedule. In this paper, the thermal process in a regenerative heating furnace was studied using fluent software, and the distribution laws of the flow field in the furnace and of the temperature field around the pipe blanks were obtained and verified experimentally. The heating furnace for pipe blanks was analyzed from multiple perspectives, including overall flow field, flow fields at different cross sections, and overall temperature field. It was found that the changeover process of the regenerative heating furnace caused the temperature in the upper part of the furnace to fluctuate. Under the pipe blanks, the gas flow was relatively thin, and the flow velocity was relatively low, facilitating the formation of a viscous turbulent layer and thereby inhibiting heat exchange around the pipe blanks. The mutual interference between the gas flow from burners and the return gas from the furnace tail flue led to different flow velocity directions at different positions, and such interference was relatively evident in the middle part of the furnace. A temperature “layering” phenomenon occurred between the upper and lower parts of the pipe blanks. The study in this paper has some significant usefulness for in-depth exploration of the characteristics of regenerative heating furnaces for steel pipes.

Simulation and Comparative Analysis on Environmental Control in Subway

2012 ◽  
Vol 209-211 ◽  
pp. 1068-1072
Author(s):  
Ming Liu ◽  
Bao Gang Zhang ◽  
Liu Wen ◽  
Zhong Zhi Huang
Keyword(s):  
Temperature Field ◽  
Energy Consumption ◽  
Comparative Analysis ◽  
Environmental Control ◽  
Thermal Environment ◽  
Airflow Velocity ◽  
Waiting Room ◽  
Local Climate ◽  
Average Temperature ◽  
Environment Control

To ensure passengers can have a comfortable thermal environment in the subway waiting room is one of the main targets in subway environment control. By using the CFD software, this paper takes an island platform with double-layer of Shenyang as the object to simulate the thermal environment of platform screen door and ventilation in the open system, then detailed analysis on the variation of the temperature field, airflow velocity field in the typical position. The results indicated that average temperature of no-PSD system platform is 2.5 ~3 °C higher than that of PSD system, standing room is 1.5 °C higher than that of PSD system , but these also meet the requirement of the standards of the environmental control and passengers’ thermal comfort. Meanwhile, through the comparative analysis to the energy consumption of the two systems, we find ventilating condition has superior to PSD system in energy saving, and it is more suitable for the local climate in the northeast.

scholarly journals Catalytic Micro Gas Sensor with Excellent Homogeneous Temperature Distribution and Low Power Consumption for Long-Term Stable Operation

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 927 ◽  
Author(s):  
Anmona Shabnam Pranti ◽  
Daniel Loof ◽  
Sebastian Kunz ◽  
Marcus Bäumer ◽  
Walter Lang
Keyword(s):  
Temperature Distribution ◽  
Low Power ◽  
Gas Sensor ◽  
Gas Flow ◽  
Pt Nanoparticles ◽  
Stable Operation ◽  
Catalytic Layer ◽  
Micro Gas Sensor ◽  
Homogeneous Temperature

This paper presents a long-term stable thermoelectric micro gas sensor with ligand linked Pt nanoparticles as catalyst. The sensor design gives an excellent homogeneous temperature distribution over the catalytic layer, an important factor for long-term stability. The sensor consumes very low power, 18 mW at 100 °C heater temperature. Another thermoresistive sensor is also fabricated with same material for comparative analysis. The thermoelectric sensor gives better temperature homogeneity and consumes 23% less power than thermoresistive sensor for same average temperature on the membrane. The sensor shows linear characteristics with temperature change and has significantly high Seebeck coefficient of 6.5 mV/K. The output of the sensor remains completely constant under 15,000 ppm continuous H2 gas flow for 24 h. No degradation of sensor signal for 24 h indicates no deactivation of catalytic layer over the time. The sensor is tested with 3 different amount of catalyst at 2 different operating temperatures under 6000 ppm and 15,000 ppm continuous H2 gas flow for 4 h. Sensor output is completely stable for 3 different amount of catalyst.

Assessment of the Fluctuations in the Microstructural Parameters of Cellulose in Wood in an Inhomogeneous Temperature Field

2018 ◽  
Vol 45 (6) ◽  
pp. 275-278
Author(s):  
N.N. Matveev ◽  
N.S. Kamalova ◽  
N.Yu. Evsikova ◽  
A.S. Chernykh
Keyword(s):  
Temperature Field ◽  
Crystallite Size ◽  
Wood Specimen ◽  
Average Crystallite Size ◽  
Potential Difference ◽  
Microstructural Parameters ◽  
Inhomogeneous Temperature ◽  
Inhomogeneous Temperature Field ◽  
Homogeneous Temperature

The possibility of assessing the average crystallite size of cellulose in wood by formalised modelling from the magnitude of the potential difference arising in the wood specimen owing to polarisation in a non-homogeneous temperature field is considered.

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