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291.
Deqing Mei Shan Yue Xiaodong Zhao Klaus Hielscher Roland Baar 《International Journal of Green Energy》2016,13(11):1120-1128
Experiments were performed in a single cylinder common-rail diesel engine that adopts a low temperature premixed charge compression ignition (PCCI) mode. Combustion features of dimethyl carbonate (DMC)-diesel blends under various centers of heat release (COHRs) were revealed in details. With retarding of COHR, all the peaks of pressure and pressure rise rate and bulk gas temperature are postponed and declined in sequence. Normally, the crank angle of peak pressure is quite close to the COHR, while the peak of bulk gas temperature appears about 7°CA after COHR as a rule. The prolongation can be demonstrated at every stage of combustion such as q10 and q90 with the COHR being put backward. In addition, the heat release of diesel is completely slower than that of D10 fuel at various stages. Unfortunately, retarding of COHR implies a declining thermal efficiency of engines as well as a higher cyclic variation in general. Nevertheless, D10 blend has higher thermal efficiency than diesel thanks to high oxygen content of DMC and low boiling point that prompts better fuel atomization and complete combustion. Meanwhile, the cyclical variation of D10 is greater than diesel fuel owing to the low heat value, high latent heat of vaporization, and poor flammability of DMC. As a total, a comprehensive understanding of PCCI combustion features under different COHRs can be conducive to conducting effective management of combustion process and manipulating the subsequent emission performance to a favorable level. 相似文献
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Glenk K 《Journal of environmental management》2011,92(3):531-541
This paper describes an approach to account for asymmetric preference formation in discrete choice models used for environmental valuation. The paper draws on data from a case study on preferences for environmental change resulting from a hypothetical rural development and conservation programme in Indonesia. Local knowledge on the current state of the environment was used to define an individual-specific status quo that consistently frames changes in a range of environmental services as gains or losses matching the perceptions of the local population living in the vicinity of a National Park. I estimated choice models that included separate parameters for increases and decreases in attribute levels for the environmental services and derived the indicators of local willingness to pay (WTP) corresponding to the bidirectional changes relative to the individual-specific status quo option. I found clear evidence of an asymmetric response to increase and decrease in attribute levels relative to the status quo. Ignoring asymmetric preference formation can therefore result in biased estimates of WTP indicators and welfare measures of change in cases where the outcomes of environmental programmes can plausibly result in both an increase and a decrease relative to a reference option. Compared to a symmetrical modelling approach, the combination of simultaneously accounting for asymmetric preference formation and preference heterogeneity in the choice model yielded additional insights that may be used to inform the development of local strategies towards biodiversity conservation. 相似文献
294.
Hnninen Jari Mkinen Katja Nordhausen Klaus Laaksonlaita Jussi Loisa Olli Virta Joni 《Environmental Modeling and Assessment》2022,27(4):571-584
Environmental Modeling & Assessment - To build a forecasting tool for the state of eutrophication in the Archipelago Sea, we fitted a Generalized Additive Mixed Model (GAMM) to marine... 相似文献
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The parthenogenetic Marmorkrebs (marbled crayfish) produces genetically uniform offspring 总被引:1,自引:0,他引:1
Genetically identical animals are very much in demand as laboratory objects because they allow conclusions about environmental
and epigenetic effects on development, structures, and behavior. Furthermore, questions about the relative fitness of various
genotypes can be addressed. However, genetically identical animals are relatively rare, in particular, organisms that combine
a high reproduction rate and a complex organization. Based on its exclusively parthenogenetic reproduction mode, it has been
suggested that the Marmorkrebs (Crustacea, Decapoda, Astacida), a recently discovered crayfish, is an excellent candidate
for research addressing the aforementioned questions. However, until now, a study using molecular markers that clearly proves
the genetic uniformity of the offspring has been lacking. Here, with this first molecular study, we show that this crayfish
indeed produces genetically uniform clones. We tested this with 19 related individuals of various generations of a Marmorkrebs
population by means of six different microsatellite markers. We found that all examined specimens were identical in their
allelic composition. Furthermore, half of the analyzed loci were heterozygous. These results and the absence of meioses in
previous histological studies of the ovaries lead us to conclude the Marmorkrebs propagates apomictically. Thus, a genetically
uniform organism with complex morphology, development, and behavior is now available for various laboratory studies. 相似文献
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