Contamination bacterienne d'une zone balneaire liee a sa frequentation

The bacterial contamination from bathers in the water and sand at a beach was investigated. Measurements were made of the composition of the cutaneous bacterial flora released by two bathers as well as the sensitivity of the main contaminants to solar radiation. The variations in bacterial concentration of the sea water and sand were determined at the sea shore over three complete day cycles. Broadly speaking, the concentration of some bacteria increases with the frequency with which the beach is used. Nevertheless, short-period variations seem to be masked by the opposing effects of solar radiation and bathers.     

铝酸钙水泥、硅酸盐水泥和β-半水石膏混合物中钙矾石的膨胀性能

本文利用现场同步加速X-射线衍射、等温量热仪和膨胀测量等手段,研究了在20℃,100%相对湿度下,由25%(重量比)的铝酸钙水泥、12.5%的硅酸盐水泥、12.5%的β-半水石膏和50%的水组成的浆体的水化。水化伊始,首先形成了石膏和钙矾石,同时半水石膏也相应消耗(0-45min内)。随后石膏继续消耗,钙矾石持续形成,2h45min后石膏消耗完毕,铝酸盐-AFm开始形成,同时钙矾石的数量在7h内保持不变。热曲线的第一个峰源自机械搅拌、初始润湿和溶解,还有钙矾石和石膏的形成,第二个峰为石膏被钙矾石所替代,第三个对应于铝酸盐-AFm的形成。石膏被钙矾石替代伴随着0.7%平均线性膨胀。     

Migration analysis using data with time intervals of differing widths

Migration data collected for periods of differing lengths will yield inconsistent population forecasts, inconsistent multiregional life tables, and alternative interpretations of mobility levels and migration patterns. In this paper, examples are first given to illustrate the effects of migration interval choice on demographic variables. The moverstayer model and its generalizations are discussed in their role as models useful in achieving consistency. It is argued that in addition to theievel of mobility, the geographic pattern of migration flows is also affected by the choice of interval width.     

Planning the post-communist city: Experiences from Sofia

This paper examines adjustments of the urban planning process to the post-communist context in the case of Sofia, the capital of Bulgaria. The main research question is whether master-planning processes have substantially changed from top-down and technocratic (as they certainly were in fascist and then communist Bulgaria) to open and participatory today. The paper tells the story of four master plans—one pre-communist, two communist, and one post-communist. It concludes that despite the increased capacity of the citizenry to both influence and challenge government planning and decision-making, there is little evidence of sharp discontinuity between past and present planning processes.     

Effects of adding organic materials to an acid sulfate soil on the growth of cocoa (Theobroma cacao L.) seedlings

Acid sulfate soils having a pH of less than 3.5 are widespread in Malaysia. Some of these soils are planted to cocoa, but the yield is reported to be low due to soil infertility related to Al toxicity. Cocoa growth is sensitive to the presence of Al in the soil. To a certain extent, Al toxicity in soils can be reduced by organic matter application and to a greater extent in iron-poor acid sulfate soil. A study was conducted to determine the efficacy of various types of organic materials easily available in the country to ameliorate acid sulfate soil infertility for growing cocoa seedlings. The treatments were control (nil), lime (3 t/ha), peat (10% w/w), peat plus green manure (10% w/w), peat plus rice straw (10% w/w), peat plus chicken dung (10% w/w) and peat plus POMS (Palm oil mill sludge) (10% w/w). The growth of cocoa seedlings was affected significantly by the presence of Al in the cocoa tissues. As the amount of Al in the leaves increased, the relative top dry weight of cocoa seedlings decreased. Likewise, the relative plant height was negatively correlated with Al in the leaves. Peat as well as peat in combination with green manure, rice straw, chicken dung or palm oil mill sludge was able to reduce Al toxicity in acid sulfate soil; the highest top dry weight of cocoa seedlings were obtained in the peat plus green manure treatment. The best cocoa seedlings root growth was found for the peat treatment alone. The relative top dry weight of cocoa seedlings was negatively correlated with Al(3+) as well as Al(3+)+Al(OH)(2+)+Al(OH)(2)(+) activity in the soil solution. The critical values for Al(3+) and the combination of Al(3+)+Al(OH)(2+)+Al(OH)(2)(+) activity in the soil solution were 10 microM and 15 microM, respectively.     

Noise impact caused by electrical energy substations in the city of Curitiba, Brazil

This survey is intended to characterize the noise impact due to electrical energy substations in the city of Curitiba over the population living in their vicinity. This impact has been studied with the aid of a computational tool capable of mapping the acoustical field of substations and their vicinity. Several factors have been considered in this survey: (1) sound power of the transformers; (2) vehicle flow on the surrounding roads; (3) positioning of the firewalls, buildings and walls; and (4) terrain topography. Four substations have been analyzed, and an acoustical map has been traced for each of them. With these maps it was possible to visualize what was the incident noise level on the building facades. The predicted noise levels have been compared to the environmental legislation of the noise emissions in effect in the city.     

Experience with the preconstruction of thawing of soils in the foundation bed of the main building of the Neryungrinsk state area power plant

Conclusions 1. The scheme that we developed is efficient and ensures thawing over a period of 40–45 days. 2. To accelerate thawing by 8–10 days when using two electric heaters in each hole, it is necessary to raise the heaters by 3–4 m after 25 days and continue thawing. 3. An 8–10-day reduction in the thaw time is also possible by using three 1.25-kW electric heaters in each hole in place of two heaters of the same capacity, installing them at depths of 20, 14, and 8 m from the surface. Taking the results of the experimental work account, the State Institute for Special Design developed a plan for the production preconstruction thawing of soils over a area of 12,380 m². The volume of soil thawed was 324,400 m³. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 3, pp. 7–8. May–June, 1982.     

Activated charcoal and microflora in water treatment

Significant sanitation was achieved by using 0.5% activated charcoal in influent and effluent of a wastewater treatment plant. The drastic reduction in the microorganisms was confirmed for twelve tester strains, including gram-positives, gram-negatives, Candida albicans, Vahlkampfia avara, Leptospira biflexa and Trichomonas foetus. The removal of microflora correlates positively with the quality of the activated charcoal used. Once adsorbed, the bacteria could not be eluted by salt, alkalinization or citric acid. Diatomaceous earth also eliminated some of the microflora, but white clay (Bolus alba) and zinc dust are inefficient. The activated carbon may be reused several times after regeneration by heat (2 h at 160°C), but eventually a slight decrease in adsorbing capacity occurs.     

Extending the Q system's prediction of support in tunnels employing fuzzy logic and extra parameters

Rock mass classifications predict support measures according to expert rules by rating rock mass and taking into account the span of the opening. A similar procedure is adopted, in this work, and computerized using statistics and fuzzy logic. Fuzzy expert systems are trained with data of previously constructed underground openings. Using subtractive clustering the systems have the intelligence to pick up the relations between input and output and define the rules that represent the system's behavior automatically. These systems are found to predict support to be used more successfully than the Q system. With the introduction of extra input variables, which are important in numerical analysis, such as depth and intact rock strength, an extended fuzzy system is developed. This system is suggested for preliminary use as it is able to predict support even better.     

Cost-benefit analysis of the use of TBT: the case for a treatment approach

The current climate of hostility towards the use of tributyltin (TBT) as an active ingredient in ship anti-fouling paint appears to be based on a very biased assessment of its environmental impact. While many national and international regulatory agencies are moving towards further restriction, and a complete ban is under active discussion, a number of factors appear to have been ignored. The economic impact of a ban on TBT when no adequate substitute exists could be substantial. Environmentally, consequences would include a substantial increase in the consumption of fossil fuel, with corresponding increases in carbon dioxide and sulphur dioxide emissions; the construction of more vessels; the transfer of ship-building, ship-repairing and ship-breaking activities from well-regulated to unregulated or under-regulated areas in the developing world; and a shift from sea transport to less environmentally acceptable forms of transport. Experience in Europe and other parts of the developed world shows that existing restrictions, where they are properly enforced, are probably adequate to alleviate the environmental damage associated with TBT. Some existing legislation acts to inhibit the search for effective substitutes. The environmental benefits of TBT have been ignored. Little thought has been given to a technical, rather than a legislative solution to controlling TBT inputs to the environment. A method is described for treating TBT-contaminated wastewaters, which has been successfully tested in prototype at full scale. Legislative measures against TBT will do nothing to address the problem of the existing backlog of contaminated material, nor even to permit the IMO proposal for the removal of TBT from all ships by 2008 to be successfully concluded in an environmentally safe manner, since no provision has been made for the disposal of the existing TBT; most probably it will be dumped in environmentally sensitive, unregulated areas in the developing world.