192 research outputs found
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Anthropogenically forced decadal change of South Asian summer monsoon across the midâ1990s
Analysis of observations indicates that there was a significant decadal change in summer (JuneâAugust) mean rainfall over South Asia and Southeast Asia across the midâ1990s, which is characterized by less rainfall over centralânorthern India and northern IndoâChina Peninsula. This study investigates impacts of anthropogenic forcing on the observed decadal change across the midâ1990s. A set of experiments using the coupled atmosphereâoceanâmixedâlayer model MetUMâGOML2 has been performed to quantify the relative roles of changes in anthropogenic greenhouse gases (GHG) and anthropogenic aerosols (AA). Results indicate a dominant role of anthropogenic changes in the observed decadal changes. Separately, the changes in GHG forcing play an important role in the reduction of rainfall over centralânorthern India through the changes of atmospheric circulation (i.e. the local Hadley circulation and the Walker circulation), with additional contribution from changes in AA forcing. The changes in AA forcing dominate the reduction of rainfall over northern IndoâChina Peninsula due to highâpressure anomalies over northern South Asia and the western subtropical Pacific. These highâpressure anomalies are induced by the surface cooling mainly via aerosolâradiation interaction that decreases downward clear sky shortwave radiation over South Asia during summer, and aerosolâradiation interaction and aerosolâcloud interaction that decrease downward shortwave radiation over the western subtropical Pacific during preâsummer seasons
Influence of air supply velocity on temperature field in the self heating process of coal
The air supply velocity is an important factor affecting the spontaneous combustion of coal. The appropriate air velocity can not only provide the oxygen required for the oxidation reaction, but maintains the good heat storage environment. Therefore, it is necessary to study the influence of the actual air velocity in the pore space on the self-heating process of coal particles. This paper focuses on studying the real space piled up by spherical particles. CFD simulation software is used to establish the numerical model from pore scale. Good fitness of the simulation results with the existing results verifies the feasibility of the calculation method. Later, the calculation conditions are changed to calculate and analyze the velocity field and the temperature field for self-heating of some particles (the surface of the particles is at a certain temperature) and expound the effect of different air supply velocities on gathering and dissipating the heat
Atmospheric responses over Asia to sea ice loss in the Barents and Kara seas in midâlate winter and early spring: a perspective revealed from CMIP5 data
This study investigated atmospheric responses in midâlate winter and early spring to sea ice loss in the Barents and Kara seas using regressions of the JanuaryâMarch mean atmosphere on Barents and Kara sea ice area in November and December. Similar atmospheric circulation responses were obtained from reanalysis data and multimodel ensemble results from the Coupled Model Intercomparison Project Phase 5, i.e., sea ice anomalies are the dominant factor driving the overlying atmosphere. The results showed that an ArcticâAsia dipole structure, with opposite anomalies over the mid-latitudes of Asia and over the adjoining Arctic, appears to be the key atmospheric circulation anomaly influencing the East Asian climate in midâlate winter and early spring
Novel composite meshes to evaluate their structural property and in vivo biocompatibility for tissue repair
Composite meshes of different types have been prepared and used for tissue repair in pelvic floor disorder. An interlocking texture mesh (inter-mesh) and a membrane coated mesh (electro-mesh) have been used based on their structural property and biocompatibility. The proportion of degradation material in inter-mesh (69.6%) is found extremely higher than that of electro-mesh (3.22%), thus leading to higher product weight (65.50±2.31 g/m2) and thickness (0.500±0.025 mm). After 4 weeks of implantation in animal experiment, inter-mesh with surrounding tissues is observed to have higher breaking strength in tensile behavoir and better flexibility. Tissues on inter-mesh are found to grow faster with larger thickness (0.76±0.033 mm). The surface area loss of inter-mesh (2.49±0.25%) is much less than that of electro-mesh (7.49±0.63 %) within the first 2 weeks of implantation. However, the materialâs degradation is accelerated after 2 weeks, leading to a higher shrinkage of 13.12±1.48 %
Novel composite meshes to evaluate their structural property and in vivo biocompatibility for tissue repair
404-410Composite meshes of different types have been prepared and used for tissue repair in pelvic floor disorder. An interlocking texture mesh (inter-mesh) and a membrane coated mesh (electro-mesh) have been used based on their structural property and biocompatibility. The proportion of degradation material in inter-mesh (69.6%) is found extremely higher than that of electro-mesh (3.22%), thus leading to higher product weight (65.50±2.31 g/m2) and thickness (0.500±0.025 mm). After 4 weeks of implantation in animal experiment, inter-mesh with surrounding tissues is observed to have higher breaking strength in tensile behavoir and better flexibility. Tissues on inter-mesh are found to grow faster with larger thickness (0.76±0.033 mm). The surface area loss of inter-mesh (2.49±0.25%) is much less than that of electro-mesh (7.49±0.63 %) within the first 2 weeks of implantation. However, the materialâs degradation is accelerated after 2 weeks, leading to a higher shrinkage of 13.12±1.48 %
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Projected near-term changes of temperature extremes in Europe and China under different aerosol emissions
This study assesses near-term future changes in temperature extremes over China and Europe in scenarios with two very different anthropogenic aerosol (AA) pathways from 2016 to 2049: a maximum technically feasible aerosol reduction (MTFR), and a current legislation aerosol scenario (CLE), both with greenhouses gas forcing following RCP 4.5. Simulations with a fully coupled atmosphere-ocean model HadGEM3-GC2 show that there is an increase in hot extremes and a decrease in cold extremes relative to the present day (1995-2014) over China and Europe in both scenarios. However, the magnitude of the changes in both hot and cold extremes depends strongly on the AA pathway. The AA reduction in MTFR amplifies the changes in temperature extremes relative to CLE, and accounts for 40% and 30% of the projected changes in temperature extremes relative to present day over China and Europe respectively. Thus, this study suggests that future and current policy decisions about AA emissions have the potential for a large near-term impact on temperature extremes
Effects of different stocking densities on the CO2 fluxes at water-air interface and the respiration metabolism in sea cucumber Apostichopus japonicus (Selenka)
Recently, abundant research has been devoted to investigating the variations of CO2 concentration in the atmosphere. However, the information of CO2 fluxes at the water-air interface remains limited, especially those from the respiratory metabolism of aquatic organisms. In the present study, a comprehensive analysis was carried out to evaluate the effects of different stocking densities of sea cucumber (Apostichopus japonicus) on the CO2 fluxes at water-air interface, and to explore the relationships between CO2 fluxes and respiratory metabolism. A total of 60 sea cucumbers were randomly classified into 4 groups with different stocking densities, including 2, 5 and 8 ind./tank (namely D2, D5 and D8 groups). After 34-day feeding trial, individuals in D5 had superior growth performance rather than D2 and D8. The analysis of modified floating static chambers clearly showed that the mean CO2 flux at the water-air interface in D5 was significantly higher than D2 and D8. Meanwhile, energy budget analysis revealed that D5 had higher carbon and nitrogen utilization, excretion energy and metabolizable energy, suggesting relatively active respiration metabolism in moderate stocking density. The activities of pyruvate dehydrogenase (PDH) and α-ketoglutarate dehydrogenase (OGDH) in respiratory tree and body wall tissues provided additional evidence for the higher respiration metabolism rate of individuals at D5, which may be responsible for the higher CO2 fluxes at the water-air interface. Transcriptome analysis was performed to uncover the molecular mechanism of respiratory metabolism affected by different stocking densities. The differentially expressed genes in respiration trees and body walls were significantly enriched in peroxisome, fatty acid degradation, and oxidative phosphorylation pathways. It may explain the differences of respiration metabolism rates at different stocking densities. The present study preliminarily revealed the CO2 fluxes variation at the water-air interface from aquatic invertebrates, and provided the scientific basis for the efficient and low-carbon agricultural technologies of sea cucumber
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