Search for dissertations about: "natural gas"

Showing result 1 - 5 of 1244 swedish dissertations containing the words natural gas.

  1. 1. Analysis of Deformation of Gas Diffusion Layers and the Impact on Performance of PEM Fuel Cells

    Author : Jiatang Wang; Värmeöverföring; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; PEM fuel cell; compression ratio; assembly pressure; porosity; deformed GDL; electric resistance; transport phenomena; model; performance; analysis; OpenFOAM;

    Abstract : Proton exchange membrane (PEM) fuel cells have been promoted due to significant breakthroughs in various aspects and increasing public interests. The porous features of the gas diffusion layer (GDL) and the necessary assembly processes generate localized pressure forces on the channel/shoulder structure of the bi-polar plates (BPP). READ MORE

  2. 2. Mid-infrared photonic devices for on-chip optical gas sensing

    Author : Floria Ottonello Briano; Kristinn B. Gylfason; Delphine Marris-Morini; KTH; []
    Keywords : ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURVETENSKAP; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; NATURAL SCIENCES; NATURAL SCIENCES; ENGINEERING AND TECHNOLOGY; ENGINEERING AND TECHNOLOGY; ENGINEERING AND TECHNOLOGY; mid-infrared; mid-IR; photonics; silicon photonics; gas sensing; optical sensing; optical gas sensing; spectroscopy; absorption; dispersion; carbon dioxide; CO2; CO2 sensing; trace gas; ethanol sensing; alcohol sensing; waveguide; photonic waveguide; ring resonator; nanowire; nanoheater; emitter; thermal source; bolometer; microbolometer; thermal detector; high frequency; 3 omega method; plasmonic; platinum; Kanthal; silicon-on-insulator; micro-electro-mechanical systems MEMS ; microfabrication; microsystems; microtechnology; nanotechnology; Optics and Photonics; Optik och fotonik; Electrical Engineering; Elektro- och systemteknik;

    Abstract : Gas detection is crucial in a wide range of fields and applications, such as safety and process control in the industry, atmospheric sciences, and breath diagnostics. Optical gas sensing offers some key advantages, compared to other sensing methods such as electrochemical and semiconductor sensing: high specificity, fast response, and minimal drift. READ MORE

  3. 3. Real-time breath gas analysis of carbon monoxide : laser-based detection and pulmonary gas exchange modeling

    Author : Ramin Ghorbani; Florian M. Schmidt; Anders Blomberg; Christoffer Boman; Staffan Schedin; Jonathan Beauchamp; Umeå universitet; []
    Keywords : MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; NATURVETENSKAP; NATURVETENSKAP; TEKNIK OCH TEKNOLOGIER; MEDICIN OCH HÄLSOVETENSKAP; NATURAL SCIENCES; NATURAL SCIENCES; ENGINEERING AND TECHNOLOGY; MEDICAL AND HEALTH SCIENCES; carbon monoxide CO ; pulmonary gas exchange; computational modeling; real-time breath gas analysis; single-exhalation profile; laser absorption spectroscopy; nonlinear least-squares fitting; breath sampling; baseline level; diurnal variation; healthy population; exposure study; fysik; Physics; Physiology; fysiologi;

    Abstract : Breath gas analysis is a promising approach for non-invasive medical diagnostics and physiological monitoring. Real-time, breath-cycle resolved biomarker detection facilitates data interpretation and has the potential to improve the diagnostic value of breath tests as exhalation profiles carry spatiotemporal information about biomarker origin and gas exchange in the respiratory tract. READ MORE

  4. 4. Determining the quality of natural gas and biomethane : Development of a correlative method and instrument prototype for measuring gas quality

    Author : Taras Koturbash; Vladimir G. Kutcherov; Andrew R. Martin; Khaled Loubar; KTH; []
    Keywords : Natural gas; biomethane; calorific value; Wobbe Index; ultrasonic measurement; sound attenuation; Energiteknik; Energy Technology;

    Abstract : The composition of natural gas highly depends on its origin: natural gas from various deposits, substitute natural gas that can be produced from fossil fuels or renewable sources. The intermixing of gases from various supply sources during pipeline transportation also leads to more complicated and unpredictable gas composition variations at the consumption site. READ MORE

  5. 5. Gas Exchange over Aquatic Interfaces and its Importance for Greenhouse Gas Emission

    Author : Jovana Kokic; Sebastian Sobek; Erik Sahlée; Marcus B. Wallin; Anne Ojala; Uppsala universitet; []
    Keywords : NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; NATURAL SCIENCES; gas exchange; lake; stream; lake sediment; headwaters; carbon dioxide; methane; greenhouse gas emission; carbon; turbulence; Biology with specialization in Limnology; Biologi med inriktning mot limnologi;

    Abstract : Aquatic ecosystems play a substantial role in global cycling of carbon (C), despite covering only about 4% of the earth surface. They emit large amounts of greenhouse gases (GHG) to the atmosphere, comparable to the amount of C stored annually in terrestrial ecosystems. In addition, C can be buried in lake sediments. READ MORE