scholarly journals A Fast-Response Automated Gas Equilibrator (FaRAGE) for continuous in situ measurement of CH<sub>4</sub> and CO<sub>2</sub> dissolved in water

2020 ◽  
Vol 24 (7) ◽  
pp. 3871-3880 ◽  
Author(s):  
Shangbin Xiao ◽  
Liu Liu ◽  
Wei Wang ◽  
Andreas Lorke ◽  
Jason Woodhouse ◽  
...  
Keyword(s):  
Response Time ◽  
Greenhouse Gas ◽  
Three Dimensional ◽  
Fast Response ◽  
In Situ Measurement ◽  
Inland Waters ◽  
Gas Analyzer ◽  
Potential Applications ◽  
Carbon Dioxide Co2

Abstract. Biogenic greenhouse gas emissions, e.g., of methane (CH4) and carbon dioxide (CO2) from inland waters, contribute substantially to global warming. In aquatic systems, dissolved greenhouse gases are highly heterogeneous in both space and time. To better understand the biological and physical processes that affect sources and sinks of both CH4 and CO2, their dissolved concentrations need to be measured with high spatial and temporal resolution. To achieve this goal, we developed the Fast-Response Automated Gas Equilibrator (FaRAGE) for real-time in situ measurement of dissolved CH4 and CO2 concentrations at the water surface and in the water column. FaRAGE can achieve an exceptionally short response time (t95 %=12 s when including the response time of the gas analyzer) while retaining an equilibration ratio of 62.6 % and a measurement accuracy of 0.5 % for CH4. A similar performance was observed for dissolved CO2 (t95 %=10 s, equilibration ratio 67.1 %). An equilibration ratio as high as 91.8 % can be reached at the cost of a slightly increased response time (16 s). The FaRAGE is capable of continuously measuring dissolved CO2 and CH4 concentrations in the nM-to-sub mM (10−9–10−3 mol L−1) range with a detection limit of sub-nM (10−10 mol L−1), when coupling with a cavity ring-down greenhouse gas analyzer (Picarro GasScouter). FaRAGE allows for the possibility of mapping dissolved concentration in a “quasi” three-dimensional manner in lakes and provides an inexpensive alternative to other commercial gas equilibrators. It is simple to operate and suitable for continuous monitoring with a strong tolerance for suspended particles. While the FaRAGE is developed for inland waters, it can be also applied to ocean waters by tuning the gas–water mixing ratio. The FaRAGE is easily adapted to suit other gas analyzers expanding the range of potential applications, including nitrous oxide and isotopic composition of the gases.

scholarly journals A Fast-response automated gas equilibrator (FaRAGE) for continuous in situ measurement of methane dissolved in water

2020 ◽  
Author(s):  
Shangbin Xiao ◽  
Liu Liu ◽  
Wei Wang ◽  
Andreas Lorke ◽  
Jason Woodhouse ◽  
...  
Keyword(s):  
Response Time ◽  
Three Dimensional ◽  
Fast Response ◽  
In Situ Measurement ◽  
Gas Analyzer ◽  
Biogenic Methane ◽  
Lakes And Reservoirs ◽  
Ch4 Concentration ◽  
Dissolved Ch4 Concentration

Abstract. Biogenic methane (CH4) emissions from inland waters contribute substantially to global warming. In aquatic systems, CH4 dissolved in freshwater lakes and reservoirs is highly heterogeneous both in space and time. To better understand the biological and physical processes that affect sources and sinks of CH4 in lakes and reservoirs, dissolved CH4 needs to be measured with a highest temporal resolution. To achieve this goal, we developed the Fast-Response Automated Gas Equilibrator (FaRAGE) for real-time in situ measurement of dissolved CH4 concentration at the water surface and in the water column. FaRAGE can achieve an exceptionally short response time (t95 % = 12 s when including the response time of the gas analyzer) while retaining an equilibration ratio of 63 % and a measurement accuracy of 0.5 %. An equilibration ratio as high as 91.8 % can be reached at the cost of a slightly increased response time (16 s). The FaRAGE is capable of continuously measuring dissolved CH4 concentrations in the nM-to-mM (10−9–10−3 mol L−1) range with a detection limit of sub-nM (10−10 mol L−1), when coupled with a cavity ring-down greenhouse gas analyzer (Picarro GasScouter). It enables the possibility of mapping dissolved CH4 concentration in a quasi three-dimensional manner in lakes. The FaRAGE is simple to operate, inexpensive, and suitable for continuous monitoring with a strong tolerance to suspended particles. The easy adaptability to other gas analyzers such as Ultra-portable Los Gatos and stable isotopic gas analyzer (Picarro G2132-i) also provides the potential for many further applications, e.g. measuring dissolved 13δC-CH4 and CO2.

A Semi-Active, High-Torque, Magnetorheological Fluid Limited Slip Differential Clutch

2006 ◽  
Vol 128 (5) ◽  
pp. 604-610 ◽  
Author(s):  
Barkan Kavlicoglu ◽  
Faramarz Gordaninejad ◽  
Cahit Evrensel ◽  
Alan Fuchs ◽  
George Korol
Keyword(s):  
Response Time ◽  
Three Dimensional ◽  
Fast Response ◽  
Design Development ◽  
Element Analysis ◽  
Mr Fluid ◽  
Bingham Plastic ◽  
Mr Fluids ◽  
Torque Transmission ◽  
And Performance

The design, development, and performance characterization of a magnetorheological (MR) fluid clutch for automotive limited slip differential (LSD) applications is presented in this study. The controllability of MR fluids provides an adjustable torque transmission and slippage for the LSD application. Three-dimensional electromagnetic finite element analysis (FEA) is performed to optimize the magnetic circuit and clutch design. Based on the results obtained from the FEA, the theoretical torque transfer capacity of the clutch is predicted utilizing Bingham-Plastic constitutive model. The clutch is characterized at different velocities and electromagnet electric input currents. Both the torque transfer capacity and the response time of the clutch were examined. It was demonstrated that the proposed MR fluid LSD clutch is capable of transferring controllable high torques with a fast response time.

scholarly journals A Fiber-Integrated CRDS Sensor for In-Situ Measurement of Dissolved Carbon Dioxide in Seawater

Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6436
Author(s):  
Mai Hu ◽  
Bing Chen ◽  
Lu Yao ◽  
Chenguang Yang ◽  
Xiang Chen ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Equilibrium Condition ◽  
Co2 Concentration ◽  
Scientific Data ◽  
In Situ Measurement ◽  
Integrated Sensor ◽  
Dissolved Carbon ◽  
Low Efficiency ◽  
Carbon Dioxide Co2

Research on carbon dioxide (CO2) geological and biogeochemical cycles in the ocean is important to support the geoscience study. Continuous in-situ measurement of dissolved CO2 is critically needed. However, the time and spatial resolution are being restricted due to the challenges of very high submarine pressure and quite low efficiency in water-gas separation, which, therefore, are emerging the main barriers to deep sea investigation. We develop a fiber-integrated sensor based on cavity ring-down spectroscopy for in-situ CO2 measurement. Furthermore, a fast concentration retrieval model using exponential fit is proposed at non-equilibrium condition. The in-situ dissolved CO2 measurement achieves 10 times faster than conventional methods, where an equilibrium condition is needed. As a proof of principle, near-coast in-situ CO2 measurement was implemented in Sanya City, Haina, China, obtaining an effective dissolved CO2 concentration of ~950 ppm. The experimental results prove the feasibly for fast dissolved gas measurement, which would benefit the ocean investigation with more detailed scientific data.

scholarly journals Soil Greenhouse Gas Emissions under Different Land-Use Types in Savanna Ecosystems of Kenya

2019 ◽  
Author(s):  
Sheila Wachiye ◽  
Lutz Merbold ◽  
Timo Vesala ◽  
Janne Rinne ◽  
Matti Räsänen ◽  
...  
Keyword(s):  
Land Use ◽  
Greenhouse Gas ◽  
Ghg Emissions ◽  
Measurement Data ◽  
Mitigation Strategies ◽  
P Value ◽  
Land Use Types ◽  
Wide Range ◽  
Carbon Dioxide Co2

Abstract. For effective climate change mitigation strategies, adequate data on greenhouse gas (GHG) emissions from a wide range of land-use and land cover types area prerequisite. However, GHG field measurement data are still scarce for many land-use types in Africa, causing a high uncertainty in GHG budgets. To address this knowledge gap, we present in situ measurements of carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) emissions in the lowland part of southern Kenya. We conducted chamber measurements on gas exchange from four dominant land-use types (LUTs) and included (1) cropland, (2) grazed savanna, (3) bushland, and (4) conservation land. Between 29 November 2017 to 3 November 2018, eight measurement campaigns were conducted accounting for regional seasonality (including wet and dry seasons and transitions periods) in each LUT. Mean CO2 emissions for the whole observation period were significantly higher (p-value 

scholarly journals Greenhouse gas emissions from boreal inland waters unchanged after forest harvesting

2018 ◽  
Author(s):  
Marcus Klaus ◽  
Erik Geibrink ◽  
Anders Jonsson ◽  
Ann-Kristin Bergström ◽  
David Bastviken ◽  
...  
Keyword(s):  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Forest Harvesting ◽  
Aquatic Systems ◽  
Inland Waters ◽  
Humic Lakes ◽  
Gas Emissions ◽  
Forestry Practices ◽  
Water Characteristics ◽  
Carbon Dioxide Co2

Abstract. Forestry practices generally result in an increased export of carbon and nitrogen to downstream aquatic systems. Although these losses affect the greenhouse gas budget of managed forests, it is unknown if they modify greenhouse gas emissions of recipient aquatic systems. To assess this question, we quantified atmospheric fluxes of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) of humic lakes and their inlet streams in four boreal catchments of which two were treated with forest clear-cuts followed by site preparation (18 % and 44 % of the catchment area) using a Before/After-Control/Impact-experiment. We measured atmospheric gas fluxes and hydrological and physicochemical water characteristics in hillslope groundwater, along stream transects and at multiple locations in lakes at 2-hourly to biweekly intervals throughout the summer season over a four year period. We found that the treatment did not significantly change greenhouse gas emissions from streams or lakes within three years of the treatment, despite significant increases of CO2 and CH4 concentrations in hillslope groundwater. Our results highlight the importance of the riparian zone-stream continuum as effective biogeochemical buffers and wind shelters to prevent greenhouse gases leaching from forest clear-cuts and evasion via downstream inland waters. These findings are representative for low productive forests located in relatively flat landscapes where forestry practices cause only a limited initial impact on catchment hydrology and biogeochemistry.

Potential Applications of Bacterial Cellulose in Environmental and Pharmaceutical Sectors

2020 ◽  
Vol 26 (45) ◽  
pp. 5793-5806
Author(s):  
Mazhar Ul-Islam ◽  
Salman Ul-Islam ◽  
Sumayia Yasir ◽  
Atiya Fatima ◽  
Md. Wasi Ahmed ◽  
...  
Keyword(s):  
Bacterial Cellulose ◽  
3D Structure ◽  
Three Dimensional ◽  
Base Material ◽  
Advanced Materials ◽  
Ex Situ ◽  
Potential Applications ◽  
Wide Readership ◽  
Water Filters

Biopolymers and their composites have been extensively investigated in recent years for multiple applications, especially in environmental, medical, and pharmaceutical fields. Bacterial cellulose (BC) has emerged as a novel biomaterial owing to its nontoxic, high-liquid absorbing and holding capacity, drug-carrying ability, and pollutant absorbing features. Additionally, its web-shaped three-dimensional (3D) structure and hydrogen bonding sites have incited a combination of various nanoparticles, polymers, and other materials with BC in the form of composites. Such BC-based composites have been developed through in-situ, ex-situ, and solution casting methods for targeted applications, such as air and water filters, controlled drug delivery systems, wound dressing materials, and tissue regeneration. This review details the production and development of BCbased composites with different materials and by various methods. It further describes various applications of BC-based composites in the environmental and pharmaceutical sectors, with specific examples from the recent literature. This review could potentially appeal a wide readership in these two emerging fields, where novel and advanced materials for different applications have been developed on a regular basis using BC as the base material.

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