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41.
The levels of lead in city street dirt and in soil from various locations in Glasgow were investigated during spring 1976. Lead concentrations in street dirt ranged from 150–2300 ppm, mean 960 ppm, and were significantly elevated with respect to the observed “natural” level of 78 ppm. Lead derived from anti-knock compounds in petrol and introduced to the environment via automobile exhausts was clearly implicated as the main source of lead pollution in a series of soil lead measurements at the centre and periphery of eight Glasgow parks.Various chemical leaching techniques were employed and compared. Less than 5% of street dirt and soil lead was found to be associated with the organic phase.  相似文献   
42.
This paper presents the development of a comfort index that measures adaptivity in outdoor spaces. Over a 9-month period 649 people were surveyed in three locations, in temperatures between 10 and 28 °C. An exploratory factor analysis develops a 15-item scale of comfort that includes measures of adaptivity: clothing, exposure time and seating location. The scale is regressed on physical measures: average instantaneous wind speed; maximum wind speed; mean-exposed radiant temperature; mean-shaded radiant temperature and ambient temperature. The results model the relative contributions of the microclimatic factors for the comfort in the outdoor space. Analyses suggest gustiness and wind speed are most important in determining user satisfaction. There is strong support for the theory that people actively adapt to microclimatic conditions.  相似文献   
43.
景观建筑学   总被引:2,自引:0,他引:2  
景观是我们生活的地区的基本结构,成熟的景观是文明社会发展最完善、最复杂的人工艺术,涵盖了相当数量的知识、经济和物质资源,它表达了人们对世界的期望,即使人在物质和精神方面都受益。对于一个成功的景观工程而言,统筹安排如何将道路、排水系统、资源和自然保护、野生动物栖息、社会空间以及建筑位置等进行控制协调是至关重要的。按照欧林事务所的经验,景观建筑师更容易具有整合各要素的能力。  相似文献   
44.
Interstitial P levels in Lake Mendota and Lake Wingra were evaluated as a function of season and water column and sediment depth. Interstitial water was obtained by the centrifugation-filtration method. Temporal variations were observed over the entire 15 cm sediment depth interval examined in all four locations evaluated. Interstitial reactive P (IRP) levels in Lake Mendota ranged from 0.014–1.67 mg l−1 at the 5–6 m water column depth and from 1.20–5.75 mg l−1 at the 18–19.5 m depth. IRP levels in Lake Wingra ranged from 0.029–2.15 mg l−1 at 3.5 m and from 0.191–3.96 mg l−1 at 2 m. Variations in interstitial P were attributed to variations in oxidation state of Fe as influenced by oxygen transport and reduction rates.  相似文献   
45.
The paper outlines some of the actions taken by Severn Trent Water to achieve compliance with consent limits since the implementation of the Control of Pollution Act (Part II) in 1985.
Prior to and since 1985, Severn Trent Water has undertaken an extensive programme to analyse the reasons for failure and carry out remedial work. A major feature of this programme, which has been further stimulated by privatization, has been the need to reduce the lead time for carrying out improvements.
The paper discusses the means by which this has been achieved, including the introduction of the 'fast-track'initiative and the 'process matrix'.
Other aspects are outlined including initiatives to develop more robust processes, computerized work scheduling, extensive training programmes and best practice studies.  相似文献   
46.
In order to protect the sensitive waters in Tolo harbour (Hong Kong), Sha Tin and Tai Po sewage-treatment works were first designed to remove 70% of the nitrogen load from the sewage. Since then, due to continuing serious eutrophication problems in the harbour, both plants have been modified to increase the removal efficiency to 90%.
The modifications were based on the Bardenpho process. However, the designers of the two plants adopted different approaches to process intensity, complexity and control of bacterial foam. At Sha Tin, the average monthly results have shown an increase of total nitrogen removal from 60–70% to about 80% since its completion. The addition of methanol was found to be ineffective on further enhancement of the denitrification rate due to difficulties in the apportioning of the second anoxic zone. The overall monthly results for Tai Po have also shown an increase in the removal rate to about 80%, even though 90% was achieved for a short period of time. The major problem encountered at the latter plant was that the process design did not provide an effective control on bacterial foaming, which had affected the smooth operation of the process.  相似文献   
47.
48.
The direct determination of 238U in various soil samples was done by measuring the 63.3-keV transition from the decay of the first daughter 234Th. Potential errors resulting from the chemical non-equilibrium of 238U with its daughters are thus avoided. The method sensitivity is 1 ppm compared to the 35 ppm obtainable by employing the 1001-keV gamma ray. A Ge(Li) gamma-ray spectrometer is the only analytical tool required. Examples are offered that demonstrate the usefulness of the technique for routine, inexpensive environmental monitoring of uranium. The technique also has the capability of providing information on the 238U/235U isotopic ratio.  相似文献   
49.
Selected tissues from four short-finned pilot whales that stranded at Cumberland Island National Seashore were analyzed for total cadmium, mercury and selenium by neutron activation. Cadmium reached a maximum mean wet weight concentration of 31.4 ppm in the kidney tissues. Maximum mean wet weight concentrations of mercury, 230.0 ppm, and selenium, 44.2 ppm, were found in the liver tissues. The lowest concentration of each metal was found in the blubber. Postmortem examination showed that the whales had no food in their stomachs. The whales must have been utilizing metabolic reserves, contaminated with residual concentrations of heavy metals, prior to beaching. This utilization of reserves probably resulted in the high concentrations of cadmium, mercury and selenium found in the liver and kidney tissues. Since the heavy metal concentrations were three to four times greater in the stranded whales, as compared to apparently healthy whales of the same species, it is suggested that heavy metal toxicosis may have been a factor contributing to this particular stranding.  相似文献   
50.
This paper quantifies and analyzes the flow of human capital caused by the migration of Blacks within the U.S. over time. Detailed characteristics of migration flows for Blacks moving in and out of each of the nine divisions in the U. S. were determined and multiplied by the appropriate value of human capital (discounted earnings approach). These flows were then summed to determine the aggregate inter-regional flows of Black human capital. The effects of age and education on these flows are analyzed as are the probable effects of such flows on regional economic growth.Results of the study show that there is a significant ageeducation interaction effect for Blacks. In addition, these interregional flows suggest that there is a substantial flow of Black human capital from the South to the North and West, and from the North to the West. Significant losses in Black human capital on the part of the South have several rather important public policy implications.  相似文献   
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