物系管理与可持续发展

该文回顾德国自60年代以来,从“末端治理型”环保政策到现在提出“物系管理”的发展变化,介绍了德国环境保护工作的成功与不足。从物系管理的产生背景出发,探讨了物系管理的概念、意义、应用实践、面临的困难。此外,该文还阐明物系管理可以成为促进中国可持续发展的一个及时、有效的工具。     

Energetics and environmental costs of agriculture in a dry tropical region of India

The present article, based on a study of five village ecosystems, assesses the energy efficiency of rain-fed agriculture in a dry tropical environment and the impact of agricultural activity on the surrounding natural ecosystems. Agronomic yield is insufficient to meet the food requirement of the human population, hence 11.5%–49.7% of the required amount of food grains are imported from the market. Energy requirements of five studied agroecosystems are subsidized considerably by the surrounding forest in the form of fodder and firewood. Natural ecosystems supply about 80%–95% of fodder needs and 81%–100% of fuelwood needs. The output-input ratio of agriculture indicated that, on average, 4.1 units of energy are expended to obtain one unit of agronomic energy. Of this, 3.9 units are supplied by the natural ecosystem. In addition, 38% of the extracted firewood is marketed. The illegal felling and lopping of trees result in ever-increasing concentric circles of forest destruction around the villages and together with excessive grazing results in savannization. The forests can be conserved by encouraging fuelwood plantations (0.7 ha/ha cultivated land) and developing village pastures (1.6 ha/ha cultivated land) and reducing the livestock numbers. Agricultural production in the region can be stabilized by introducing improved dry farming techniques such as intercropping, planned rainwater management, and adequate use of fertilizers.     

The relationship between resources and living standards

Available estimates of potentially recoverable world mineral and fuel resources are examined with a view to determining whether everyone likely to be living on earth next century could be raised to the material living standards people in developed countries now have. It is concluded that this goal is impossible. A number of fundamentally important implications follow, especially regarding the inappropriateness of growth strategies in general, goals for Third World development, and the need for ‘de-development’ of developed countries to much more frugal, self-sufficient and cooperative social systems.     

含铁地下水取水构筑物进水面上的腐蚀与沉积

地下水取水构筑物早期报废的原因错综复杂,而含铁地下水取水构筑物的早期报废问题常常比一般情况更为突出,本文对含铁地下水取水构筑的进水面上的腐蚀与沉积问题进行了初步探讨,供分析研究。     

Households’ recycling efforts

Households’ recycling effort is often argued to be of an insignificant size. It is also frequently argued that this contribution, if significant, is not a cost to households, since it is voluntary. Thus households’ use of time and energy are frequently disregarded in cost-benefit analyses of stricter recycling targets. In this survey, based on 1162 interviews, we find that sorting at source involves significant extra use of time and energy in the households. On average, each of those asked reported that they use close to half an hour a week for cleaning, sorting and transporting recyclable waste. On average, 185 h is used per tonne of waste. Four out of ten reported that they use warm or hot water to clean the materials. When investigating the motives for sorting waste, we find that many perceive sorting as mandatory, while some in fact find it a pleasant activity in itself. Moral motives for sorting at source are also widespread. A majority would prefer that a company took over the sorting if this were possible, and on average, the respondents are willing to pay US$ 20/year for this service.     

提高水基热气溶胶灭火剂燃速途径的研究

水基热气溶胶灭火剂是以替代哈龙为目的而研制的新一代气溶胶灭火剂；因为其燃烧速度对灭火效率有重大影响，故本文在理论分析的基础上，采用加入金属粉提高导热系数，增加反应放热量；加入正催化剂降低反应活化能；在反应器中采用导流管除去燃烧表面的液态产物，加强燃烧反应的热反馈等方式提高灭火剂燃速。     

特殊阻力与喷枪喷头结构合理设计

喷枪喷头的结构设计和加工质量可大幅度地影响射流质量和喷射效果。本文重点论述了合理结构设计对减少特殊阻力、提高喷头效率的影响。同时提出了减少特殊阻力的具体措施。这对提高射流的打击效果和工作效率大有稗益。     

Performance analysis of different orc power plant configurations using solar and geothermal heat sources

ABSTRACT

Energy optimization is performed on hybrid solar-geothermal power plant working according to Organic Rankine Cycle and installed in southern Tunisia. The performances of four different configurations of the power plant are studied. Mass and energy balances are established for the different compounds. The effects of the main operating parameters such as the geothermal water temperature, ambient temperature and direct normal irradiation on the power plant performances are analyzed. A code is established using Engineering Equation Solver software (EES) to perform the required calculations. Obtained results show that the hybrid solar-geothermal power plant with a heat recovery system is the most suitable configuration design giving a better overall energy efficiency of 15.77 and13.11% and a maximum net power of 1089 and 1882 kW in winter and summer, respectively. However, in the summer season, using a heat recovery system can valuable only when the water temperature is higher than 66°C. For air-cooled condenser, the suitable condensing pressure is 1 bar in winter and 1.9 bars in summer.     

Energy conservation and thermal comfort in a New York city high rise office building

Detailed analysis of an energy conservation program implemented on a 46 story government building is presented. Conservation was achieved by reduced lighting, changes in building operating hours, thermostat settings of 20C (68F) in the winter and 27C (80F) in the summer, and the elimination of air conditioning reheat. As a result, energy consumption in the summer was reduced by 54 percent. A survey of the occupants' thermal comfort and the insulating value of thei r clothing was taken. In the summer 68 percent were comfortable compared with 80 percent in the winter. The insulating value of the clothing worn by the women was consistently less than that of the men; the difference was largest in the summer. Though the temperatures in the occupied spaces were not as cold or as warm as the thermostat settings, the survey indicates that comfort could be improved if occupants dressed more appropriately for the expected thermal environment of the work place.An energy analysis with a building simulation program (NBSLD) was also undertaken. The simulated energy consumption was within 5 percent of the measured values. Additional large savings may be achieved in this and similar buildings through a reduction in the energy cost of transporting air and chilled and hot water around the building for the environmental control systems.     

Market and nonmarket values of the Georgia landscape

Natural landscapes produce goods and services, such as fish, wildlife, recreation, climate control, that are not adequately incorporated in their market values. Contingent Valuation (CV) and Energy Analysis (EA) approaches were used to estimate the nonmarket value of forests in Georgia. Both methods yielded similar estimates of approximately $200 ha^–1, which was 31% of the total market and nonmarket value of forests. Energy analysis was also used to estimate the nonmarket value of the major land uses in Georgia. Relative contributions of nonmarket value to total value ranged from 0.1% for urban areas to approximately 100% for wetlands. For the state as a whole, nonmarket production of natural and developed ecosystems was estimated at $2.6 billion. This value is comparable to annual marketed agricultural ($2.8 billion) and timber ($4.5 billion) production, both very important industries in Georgia. Changing land use patterns in Georgia and elsewhere are likely to be accompanied by shifts in the relative importances of market and non-market values.