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Topic Review
Gas-Liquid Membrane Contactors with Aqueous-Amine Solvents
Gas–liquid membrane contactor (GLMC) is a promising process intensification technology for offshore natural gas conditioning in which weight and footprint constraints impose severe limitations. Thanks to its potential for substituting conventional packed/trayed columns for acid-gas absorption and acid-gas solvent regeneration, gas-liquid membrane contactors have been investigated experimentally and theoretically, wherein aqueous-amine solvents and their blends are the most employed solvents for carbon dioxide removal from natural gas in gas-liquid membrane contactors. 
  • 659
  • 19 Sep 2022
Topic Review
Gas-Sensing Characteristics of Metal Oxide Semiconductor Sensors
The sensing characteristics of metal oxide semiconductors (MOSs) depend on the carrier concentration, which is relevant to the working temperature. The characteristic parameters commonly used to measure gas-sensing performance include optimal working temperature, sensitivity, selectivity, stability, repeatability, response and recovery time, and the lowest detection limits.
  • 2.0K
  • 29 Jun 2022
Topic Review
Gas–Liquid Slug Flow in Honeycomb Microchannel Reactor
The microreactor is characterized by large specific surface area, short diffusion transmission path and strong controllability. The pressure distribution inside the microreactor was closely related to the phase distribution. The increasing inlet gas velocity increased the gas phase volume fraction, as well as the gas slug length. Higher gas velocity resulted in stronger turbulence of the liquid phase flow field and a deviation of residence time distribution from normal distribution, but it was favorable to even more residence time during the liquid phase. There also exists a secondary flow in the gas–liquid interface.
  • 454
  • 07 Mar 2022
Topic Review
Gas/Oil-Relative Permeabilities
Thermal recovery processes for heavy oil exploitation involve three-phase flow at elevated temperatures. The mathematical modeling of such processes necessitates the account of changes in the rock–fluid system’s flow behavior as the temperature rises. To this end, numerous studies on effects of the temperature on relative permeabilities have been reported in the literature. Compared to studies on the temperature effects on oil/water-relative permeabilities, studies (and hence, data) on gas/oil-relative permeabilities are limited. However, the role of temperature on both gas/oil and oil/water-relative permeabilities has been a topic of much discussion, contradiction and debate. The jury is still out, without a consensus, with several contradictory hypotheses, even for the limited number of studies on gas/oil-relative permeabilities. This study presents a critical analysis of studies on gas/oil-relative permeabilities as reported in the literature, and puts forward an undeniable argument that the temperature does indeed impact gas/oil-relative permeabilities and the other fluid–fluid properties contributing to flow in the reservoir, particularly in a thermal recovery process. It further concludes that such thermal effects on relative permeabilities must be accounted for, properly and adequately, in reservoir simulation studies using numerical models. The paper presents a review of most cited studies since the 1940s and identifies the possible primary causes that contribute to contradictory results among them, such as differences in experimental methodologies, experimental difficulties in flow data acquisition, impact of flow instabilities during flooding, and the differences in the specific impact of temperature on different rock–fluid systems. We first examined the experimental techniques used in measurements of oil/gas-relative permeabilities and identified the challenges involved in obtaining reliable results. Then, the effect of temperature on other rock–fluid properties that may affect the relative permeability was examined. Finally, we assessed the effect of temperature on parameters that characterized the two-phase oil/gas-relative permeability data, including the irreducible water saturation, residual oil saturation and critical gas saturation. Through this critical review of the existing literature on the effect of temperature on gas/oil-relative permeabilities, we conclude that it is an important area that suffers profoundly from a lack of a comprehensive understanding of the degree and extent of how the temperature affects relative permeabilities in thermal recovery processes, and therefore, it is an area that needs further focused research to address various contradictory hypotheses and to describe the flow in the reservoir more reliably.
  • 2.2K
  • 14 Jul 2020
Topic Review
Gaseous and Liquid Fuel Cook-Stove
Clean and efficient cook-stoves and fuels are essential to address energy demand and ensure safe cooking for billions of people across the globe. Currently, nearly 2651 million people in developing countries (Africa—910 million, Asia—1674 million, Central and South America—57 million, and Middle East—10 million) are without clean cooking facilities.
  • 1.5K
  • 03 Feb 2023
Topic Review
Gaseous Emissions from the Composting Process
Compost can be used in agricultural activities due to its various positive impacts on the physical and chemical properties of the soil, meanwhile reducing utilization of inorganic fertilizers. Composting has also negative environmental impacts, some of them of social concern. This is the case of composting atmospheric emissions, especially in the case of greenhouse gases (GHG) and certain families of volatile organic compounds (VOC). 
  • 1.1K
  • 27 Oct 2021
Topic Review
Gaspee Affair
Script error: No such module "Infobox military conflict". The Gaspee Affair was a significant event in the lead-up to the American Revolution. HMS Gaspee was a British customs schooner that had been enforcing the Navigation Acts in and around Newport, Rhode Island in 1772. It ran aground in shallow water while chasing the packet ship Hannah on June 9 near Gaspee Point in Warwick, Rhode Island. A group of men led by Abraham Whipple and John Brown attacked, boarded, and torched the ship. The event increased tensions between the American colonists and British officials, following the Boston Massacre in 1770. British officials in Rhode Island wanted to increase their control over trade—legitimate trade as well as smuggling—in order to increase their revenue from the small colony. But Rhode Islanders increasingly protested the Stamp Act, the Townshend Acts, and other British impositions that had clashed with the colony's history of rum manufacturing, maritime trade, and slave trading. This event and others in Narragansett Bay marked the first acts of violent uprising against the British crown's authority in America, preceding the Boston Tea Party by more than a year and moving the Thirteen Colonies as a whole toward the war for independence.
  • 1.8K
  • 18 Oct 2022
Topic Review
Gate-Level Static Approximate Adders
This work compares and analyzes static approximate adders which are suitable for FPGA and ASIC type implementations. We consider many static approximate adders and evaluate their performance with respect to a digital image processing application using standard figures of merit such as peak signal to noise ratio and structural similarity index metric. We provide the error metrics of approximate adders, and the design metrics of accurate and approximate adders corresponding to FPGA and ASIC type implementations. For the FPGA implementation, we considered a Xilinx Artix-7 FPGA, and for an ASIC type implementation, we considered a 32-28 nm CMOS standard digital cell library. While the inferences from this work could serve as a useful reference to determine an optimum static approximate adder for a practical application, in particular, we found approximate adders HOAANED, HERLOA and M-HERLOA to be preferable.
  • 865
  • 14 Dec 2021
Topic Review
GAZ Tigr
The GAZ Tigr (Russian: Тигр and English: Tiger) is a Russia n 4x4, multipurpose, all-terrain infantry mobility vehicle manufactured by GAZ, first delivered to the Russian Army in 2006. Primarily used by the Russian Federation's armed forces, it is also used by numerous other countries.
  • 7.0K
  • 26 Oct 2022
Topic Review
GDL for Proton Exchange Membrane Fuel Cells
Proton exchange membrane fuel cells (PEMFCs) are an attractive type of fuel cell that have received successful commercialization, benefitted from its unique advantages (including an all solid-state structure, a low operating temperature and low environmental impact). In general, the structure of PEMFCs can be regarded as a sequential stacking of functional layers, among which the gas diffusion layer (GDL) plays an important role in connecting bipolar plates and catalyst layers both physically and electrically, offering a route for gas diffusion and drainage and providing mechanical support to the membrane electrode assemblies. 
  • 1.0K
  • 13 Dec 2022
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