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921.
922.
It is generally accepted as a useful and workable hypothesis that when an ecosystem receives an inflow of exergy (energy that can do work) it will utilize this flow of exergy to move as far away from thermodynamic equilibrium as possible after the exergy (energy) for maintenance has been covered. If more combinations of system components including organisms are offered, the combination of components and processes that will bring the system most away from thermodynamic equilibrium will win.The amino acid sequences of the proteins e.g. enzymes determine and control the life processes of the organisms and may be viewed as information sensu lato. The free energy of oxidation of the amino acids and the peptide bonds of the cell enzymes expresses therefore the exergy content, eco-exergy or work capacity that the information contributes to “moving further away from thermodynamic equilibrium”. In this paper eco-exergy is calculated and plotted versus the β-values (a measure of the information contained in the genome) for different organisms. The eco-exergy density was previously (see [J?rgensen et al., 1995] and [J?rgensen et al., 2005]) proposed to be calculated as the summation of the product of the β-values representing the information of the genome multiplied by the concentrations of the respective ecosystem components. This analysis shows a strong correlation between the β-values and free energy released when oxidizing the enzymes. The β-values can therefore be assumed to represent the free energy that the organisms have invested in genetic information.  相似文献   
923.
Carrousel氧化沟的三维流场模拟与分析   总被引:1,自引:0,他引:1  
利用CFD的Fluent软件,采用标准的三维K—ε紊流模型,对桂林市七里店污水处理厂1#氧化沟的流场进行了数值模拟,对导流墙和推进器附近的流速进行了计算分析。结果表明,氧化沟下层流速较低,局部区域流速低于0.2m/s。为了防止污泥沉降,应进一步降低推进器位置。能量损失分析表明,卡罗塞氧化沟能量损失主要来源于沿程摩擦损失和局部损失。可通过增加墙体光滑度、降低入口高度以及增加导流墙的曲率半径等措施减少能量损失,改善现有氧化沟的水力特征。  相似文献   
924.
The increasing levels of global warming, depleting sources of fossil fuels and increasing energy costs are all having a large detrimental effect on today's society. Many efforts are being made to try and increase energy efficiency all over the world. One of the major problems is unnecessary and excessive energy utilisation. This problem has been identified by Loughborough University and they are making efforts to try and reduce energy wastage. One of their strategies, used up until recently, involved increasing energy awareness within students in halls of residence by means of a reward system called the Residential Halls Energy Efficiency League (Imago Services, Loughborough Students Union, Estates Services 2006). This scheme managed to reduce energy consumption by up to 10%, saving an estimated £9000 in only 52 days. Can those results be improved by targeting students more specifically? How much energy can be saved by increasing energy awareness?  相似文献   
925.
Extrusion-coating experiments were carried out in the pilot line at Tampere Univesity of Technology (Institute of Paper Converting). Typical paper and paperboard substrates were coated with commercially produced 3-hydroxybutyrate/3-hydroxyvalerate. The resulting physical properties of extrusion-coated composite structures were studied. Adhesion between PHB/V and a fiber-based substrate was rather poor, regardless of typically used pretreatments (corona and flame). On the other hand, adhesion was sufficient (mode of failure was fiber tear as the materials were separated) when the substrate was primed with an acrylic-based primer. The surface energy and polarity of PHB/V were much higher than the respective ones of LDPE. Curling of PHB/V was reduced by the addition of wax or tall oil rosin into the base polymer.  相似文献   
926.
漫湾水电站是澜沧江水能梯级开发的第一个干流大型水电站,加强库区水土流失治理与监督监测尤为必要,而降雨侵蚀力的时空分布规律研究则是实现区域土壤侵蚀定量监测预报的重要基础。根据有关降雨侵蚀力的计算方法,利用漫湾电站库区4个测站1980~2000年的逐月平均降雨资料,估算了其降雨侵蚀力R值的时空分布规律及其变化特征。结果表明:漫湾电站库区多年平均降雨侵蚀力在1 9336~3 9727 MJ·mm/hm2·h;R值的年内变化显著,且较大值集中分布在雨季的5月~10月,平均R值占全年的867%,尤其6~8月连续3个月的降雨侵蚀力平均占全年侵蚀力的一半以上;R值的年际变化显示20世纪90年代漫湾电站库区降雨侵蚀力比80年代平均增加2835 MJ·mm/hm2·h;R值的空间分布上以凤庆站点的年降雨侵蚀力最大;南涧站点的年降雨侵蚀力最小,但是其年际波动幅度较大。全面地分析了漫湾电站库区降雨侵蚀力R值的时空变化特征,为该地区有效防止与监测水土流失情况、更好地安置水电站工程移民提供参考。  相似文献   
927.
Fruit, vegetable, flower waste (FVFW), dairy products waste (DPW), meat waste (MW) and sugar waste (SW) obtained from a supermarket chain were anaerobically digested, in order to recover methane as a source of renewable energy. Batch mesophilic anaerobic reactors were run at total solids (TS) ratios of 5%, 8% and 10%. The highest methane yield of 0.44 L CH4/g VSadded was obtained from anaerobic digestion of wastes (FVFW + DPW + MW + SW) at 10% TS, with 66.4% of methane (CH4) composition in biogas. Anaerobic digestion of mixed wastes at 5% and 8% TS provided slightly lower methane yields of 0.41 and 0.40 L CH4/g VSadded, respectively. When the wastes were digested alone without co-substrate addition, the highest methane yield of 0.40 L CH4/g VSadded was obtained from FVFW at 5% TS. Generally, although the volatile solids (VS) conversion percentages seemed low during the experiments, higher methane yields could be obtained from anaerobic digestion of supermarket wastes. A suitable carbon/nitrogen (C/N) ratio, proper adjustment of the buffering capacity and the addition of essential trace nutrients (such as Ni) could improve VS conversion and biogas production yields significantly.  相似文献   
928.
Fuelwood is one of the major sources of energy in the domestic sector across the rural areas,especially in the developing regions across the world.The Northeastern Himalayan state of Manipur is dominated by the tribal population that largely depends on fuelwood from the nearby forest area.The entire dependence on forests for energy resources is affecting the sustainability of the forest ecosystem in the region,thus indicating the livelihood conditions.Since land-use land-cover change is the key driver to the change in resource availability of a region,the present study has tried to analyze the landcover changes over a period 28 years.The second major component affecting resource availability is the increasing population pressure that leads to changes in the land dynamics,which directly affect the resource production.Based on the existing consumption pattern,the total consumption of fuelwood in the watershed ranges fiom a minimum of 289.992 tons/year to a maximum of 3545.719 tons/year with an average of 1561.956 tons/year in the year 2009 and simulated fuelwood consumption for the year 2021 is around 1469.260 tons/year.Nine different probable scenarios of resource are proposed to calculate the stress value that can be used by the policy-makers and planners for suitable policy implementation at the micro level with a complex social system.  相似文献   
929.
In the electricity sector, innovation in large-scale storage is anticipated to reduce costs and improve performance. The effect on greenhouse gas emissions of lower storage costs depends on the interactions between storage and the entire grid. The literature has disagreed on the role of storage in reducing emissions. In this paper we present a stylized model, which suggests that the effect of storage costs on emissions depends on the supply responsiveness of both fossil and renewable generators. Under common conditions in the United States, lower storage costs are more likely to reduce emissions when wind investment responds to equilibrium electricity prices and when solar investment does not. Simulations of a computational model of grid investment and operation confirm these intuitions. Moreover, because of its effect on coal and natural gas–fired supply responsiveness, introducing a carbon dioxide emissions price may increase the likelihood that lower storage costs reduce emissions.  相似文献   
930.
In the wake of the Fukushima nuclear accident, alternative energy paths have been discussed for Japan, but except for a few studies the assumption is usually made that Japan is too densely populated to be suited for a near-100% sustainable, indigenous energy provision. The studies emphasizing renewable energy have proposed the use of photovoltaic power as the main source of electricity supply, in combination with diurnal battery storage and supplemented by other renewable sources such as wind, hydro, and geothermal power. Here, an alternative approach is explored, with wind and derived hydrogen production as the main energy source, but still using solar energy, biofuels, and hydropower in a resilient combination allowing full satisfaction of demands in all sectors of the economy, i.e., for dedicated electricity, transportation energy as well as heat for processes and comfort. Furthermore, the possible advantage of establishing a regional energy system with energy interchange and coordinated management of the mix of renewable energy resources across a wider region is discussed. As the closest neighbor, the energy system of South Korea is considered, first regarding the possibility of a similar full renewable energy reliance, and then for possible synergetic effects of connecting the Korean and the Japanese energy systems, in order to be able to better cope with the intermittency of renewable energy source flows.  相似文献   
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