Feasibility Assessment of Basin Solar Stills

The present study assesses the feasibility of exploiting single- and double-basin solar stills in our daily lives. An investigation is carried out to determine the thermal performance and economic viability of making use of solar stills in water desalination. The climatic conditions of Tehran (35°44?N, 51°30?E) are considered to assess the feasibility of the basins. Transient energy and mass balance equations are utilized for modeling the thermal performance. The equations are solved by using fourth-order Runge–Kutta method in FORTRAN. The daily productivities of single- and double-basin solar stills are found to be 5.22 kg/m² and 7.73 kg/m², respectively, while the effect of different water masses (20–100 kg) on the productivity of each system was found to be optimum at 20 kg/m². The results are compared with experimental work performed under different climatic conditions to examine the validity of the feasibility of basins in general. A life cycle cost analysis performed for Tehran, yields that single- and double-basin solar stills have savings-to-investment ratios of 4.2 and 4.8, respectively, indicating that they are economically feasible.     

Assessing the impact of leather industries on the quality of water discharged into the East China Sea from Wenzhou Watersheds

Ammonium nitrogen and total germanium are among the main pollutants in the wastewater discharged from the leather industry. The intake of high concentrations of ammonium nitrogen and/or total germanium harms human health and biological species, as is well documented in literature. This paper focuses on assessing the trends of ammonium nitrogen and total germanium concentrations through time in two watersheds (Aojiang and Oujiang) in the Wenzhou metropolitan area of Zhejiang Province and their relationships with the released wastewater using regression and correlation statistics. The paper also utilizes the integrated pollution index to evaluate water quality in the two watersheds. Preliminary results show that, from 1992 to 1998 in the Aojing watershed, the concentrations of ammonium nitrogen and total germanium increased 13 and 14 times, respectively, decreasing somewhat after 1998, while between 1992 and 1997 in the Oujiang watershed, the concentrations increased, then decreased after 1997. The concentrations of ammonium nitrogen and total germanium are positively related to the amount of released wastewater. The concentrations of ammonium nitrogen and total germanium exceeded water standards 12 and 3 times, respectively, in Pingyang county of the Aojiang watershed, 14 and 3.3 times in Lucheng District of the Oujiang watershed, and 14 and 3.8 times in the Ouhai Oujiang watershed, respectively. In Pingyang county of the Aojiang watershed, the water quality degraded from Type III in 1992 to over Type V in 2003, and in the Oujiang watershed, the water quality degraded from Type II to over Type IV in 1999, when they were compared with the water quality standards. The water quality slightly improved in 2003 for the Oujiang watershed. It appears that pollution did have a direct positive correlation with leather industry production in the Pingyang Aojing watershed, while there was a negative correlation between the two in the Oujiang watershed. In these two watersheds, the integrated pollution index did not appear to relate to population dynamics and agricultural production. This paper also discusses the current new methodologies and approaches adopted nationally and internationally to reduce the contaminants and purify the environment for maintaining a sustainable and healthier environment in Wenzhou.     

Erosional Consequence of Saltcedar Control

Removal of nonnative riparian trees is accelerating to conserve water and improve habitat for native species. Widespread control of dominant species, however, can lead to unintended erosion. Helicopter herbicide application in 2003 along a 12-km reach of the Rio Puerco, New Mexico, eliminated the target invasive species saltcedar (Tamarix spp.), which dominated the floodplain, as well as the native species sandbar willow (Salix exigua Nuttall), which occurred as a fringe along the channel. Herbicide application initiated a natural experiment testing the importance of riparian vegetation for bank stability along this data-rich river. A flood three years later eroded about 680,000 m³ of sediment, increasing mean channel width of the sprayed reach by 84%. Erosion upstream and downstream from the sprayed reach during this flood was inconsequential. Sand eroded from channel banks was transported an average of 5 km downstream and deposited on the floodplain and channel bed. Although vegetation was killed across the floodplain in the sprayed reach, erosion was almost entirely confined to the channel banks. The absence of dense, flexible woody stems on the banks reduced drag on the flow, leading to high shear stress at the toe of the banks, fluvial erosion, bank undercutting, and mass failure. The potential for increased erosion must be included in consideration of phreatophyte control projects.     

战略环境评价在中国的发展及方法学探讨

本文在回顾和评述战略评价（SEA）的发展状况的基础上，从概念和实践的角度，对SEA方法学作了初步探讨，并提出SEA方法学研究的一般思路。     

Strategies for determining soil-loss tolerance

Excessive soil losses due to erosion or lateral displacement by machinery impair productivity. Some soil loss is tolerable, but not so much that plant productivity diminishes. Thus productivity is the dominant concern in determining soil-loss tolerance. The effects of soil loss on productivity, however, are difficult to determine. Therefore, two alternatives are discussed for determining the limits of soil loss, or soil-loss tolerance. These alternatives are the maintenance of soil organic matter and, for shallow and moderately deep soils, the maintenance of soil depth. They are not new strategies, but our rapidly increasing knowledge of the dynamics of soil organic matter and the rates of soil formation from bedrock or consolidated sediments warrants the reconsideration of these alternatives. Reductions in either soil organic matter or the depth of shallow or moderately deep soils will lead to declining productivity. Soil organic matter, considered to be a surrogate for productivity, is much easier to monitor than is productivity. Also, there are many computer models for predicting the effects of management on soil organic matter. Recently compiled data on rates of soil formation suggest that soil losses of 1 t/a (2.24 Mg/ha yr) are greater than the rate of replenishment by the weathering of lithic or paralithic material in all but very wet climates.     

关于燃煤电厂环境影响评价工作中的一些问题

对燃煤电厂的环评工作中，项目选址、总平面布置、污染防治与清洁生产：冷却塔噪声等一些值得注意的问题进行了探讨，并提出了一些初步意见。     

The impact of a nationwide effort to reduce airbag-related deaths among children: an examination of fatality trends among younger and older age groups

INTRODUCTION: The purpose of this study was to examine the impact of a nationwide response to emerging airbag-related deaths among children. This response, implemented in 1996, focused on moving children to a rear seat and increasing proper restraint usage. METHOD: Fatality trends from 1992 through 1996 and from 1996 through 2003 were examined for younger children (ages 0-3) and for older children (ages 4-12). RESULTS: Prior to 1997, a steady reduction in unrestrained deaths (among younger children) was offset by increases in restrained deaths (among younger and older children), increases in rear-seat deaths (among younger children), and increases in front-seat deaths (among older children). After 1996, there were significant decreases in fatalities in both age groups, with larger and more immediate reductions among the younger children. The largest reductions were immediately after 1996, when younger-child deaths declined by 16%, and after 1999, when deaths among both age groups declined by about 16%. CONCLUSIONS: The immediate reduction in front-seat deaths among younger children, particularly infants, appears to have been closely associated with the nationwide public information efforts implemented in 1996. Later reductions in front-seat and unrestrained deaths, among both younger and older children, were likely associated with the combination of legislative, enforcement, and public information programs, which increased after 1999. IMPACT ON INDUSTRY: The findings suggest that a large expenditure of resources by public and private-sector organizations after 1996 resulted in the prevention of hundreds of deaths among young children. In addition, the results provide insights with regard to the categories of deaths most affected by such programs and issues that deserve additional attention.     

Growth accounting in a fishery

Since 1950, the real value of fish catches in Norway has about doubled, while the number of fishermen has declined by about 85 percent. This has made it possible to maintain fishermen's incomes roughly on par with other occupational groups in Norway. It is investigated to what extent this increase in labor productivity is due to accumulation of capital, increasingly abundant fish stocks, or technological progress. Since the capital stock in recent years is not much greater in real terms than in the early 1960s, it is tempting to ascribe most of the increase in labor productivity to technical progress. This, however, would leave out the role of fish stocks; if stocks have increased over this period, this would explain some of what otherwise appears as a technical progress. Using data on labor, capital, fish catches, and fish stock abundance 1961–2004 the development of total factor productivity is examined. Ignoring changes in fish stocks, total factor productivity is estimated to have increased by 0.8 percent per year. Accounting for changes in fish stocks raises this to 1.7–4.3 percent per year, depending on the importance assigned to stocks as factors of production.     

Constraints on foraging success due to resource ecology limit colony productivity in social insects

The benefit of group living is a fundamental question in social evolution. For sociality to evolve, each individual must gain in terms of some fitness component by living in larger groups. However, in social insects, a decrease in per capita success in brood production has been observed in larger groups. While it has been proposed that this decrease could be outweighed by an increase in the predictability of success, a functional basis to this hypothesis has so far never been demonstrated. In this paper, using foraging economics as a functional proxy to colony productivity, we construct a model to explore how number of foragers in the colony interacts with the ecology of resources to influence per capita foraging success and its predictability. The results of the model show that there is no increase in per capita foraging success in larger colonies under most circumstances, though there is an increase in its predictability. We then test the model with empirical data on the foraging behavior of the primitively eusocial wasp, Ropalidia marginata. The consistency between the data and the model suggests that foraging economics could provide a robust functional basis in explaining the relationship between colony size and productivity.     

广州李坑垃圾填埋场水环境污染调查

通过现场采样与历史资料统计，分析了广州市李坑垃圾填埋场垃圾渗滤液的水质特征，及其对地睛水和地表水的影响强度及范围，结果表明，该场对环境产生影响的主要污染物是以ＮＨ３－Ｎ、ＣＯＤＣｒ为代表的高浓度有机物、垃圾渗滤液对地下水的影响强度不大，对作为农业灌溉用水的地表水影响不超过２０００ｍ，对１０ｋｍ上的饮用水源不造成影响