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611.
612.
The Science of Nature - 相似文献
613.
The effects of predominant currents on the morphology of coral reefs has been studied in the leeward patch reefs of Anegada, British Virgin Islands. Measurements of current velocity and direction and sediment characteristics together with mapping of approximately 31 patch reefs within a 2 km2 area suggest that even under relatively low but constant current velocities (surface current 20 cm sec-1) the major reef-building corals show definite distribution patterns on the reef. The currents also appear to be responsible, in part, for marked orientation and elongation of patch reefs in a north-west/ south-east direction and for a gradation of patch-reef type across the study area. 相似文献
614.
Albin Brandstetter Roger L. Engel Dennis B. Cearlock 《Journal of the American Water Resources Association》1973,9(6):1188-1200
ABSTRACT: A comprehensive mathematical model (Urban Wastewater Management Model) has been developed to continuously simulate time-varying wastewater flows and qualities in complex metropolitan combined sewerage systems. The model serves three functions: (1) assessment of existing or planned system performance in relation to other wastewater discharges in either a metropolitan or river basin area; (2) determination of the optium operation or automatic control of existing or planned systems during rainstorms; and (3) determination of the most economically feasible combination of design alternatives for improving or expanding existing systems to meet specified performance criteria. The model provides an efficient engineering tool for evaluating and controlling pollutant discharges from combined sewerage systems (including treatment plants) to receiving waters, while considering the time and spacial variations of rainfall and dry-weather flows and qualities as well as economic constraints. 相似文献
615.
B. Fullerton Dr R. C. Wilkinson Jeremy Howells Naima Chabbis M. F. Downing 《Journal of Environmental Planning and Management》1986,29(2):98-100
URBANIZATION AND COMMUNITY BUILDING IN MODERN NORWAY
J. S. Tortenson, M. F. Metcalfe, T. F. Rasmussen
Urbana Press, Oslo 1985. 312 pp., figs and tables.
REGIONAL DEVELOPMENT POLICY
R. Riddell
Gower, 1985. £18.50
REVIEW OF SERVICE INDUSTRIES: A GEOGRAPHICAL APPRAISAL
P. W. Daniels
Methuen, 1985. £27.50.
ARABIC‐ISLAMIC CITIES: BUILDING AND PLANNING PRINCIPLES
Besim Selim Hakim
KPI Ltd., London, 1986. pp. 192. £46 (h/b)
FIFTY YEARS OF LANDSCAPE DESIGN
Sheila Harvey and Stephen Rettig
The Landscape Press, 1985. £12.50
CAPABILITY BROWN AND THE EIGHTEENTH CENTURY ENGLISH LANDSCAPE
Roger Turner
Weidenfeld & Nicholson. £16.95. 相似文献
616.
Dilution of indoor air contaminants with less contaminated outdoor air is the most common strategy for control of indoor air quality. Unfortunately this strategy frequently imposes a substantial energy burden. If the contaminants are associated with occupants and their activities, a ventilation control system based on the carbon dioxide level in the controlled space is shown to relieve this energy burden. A test was carried out in the Fridley, MN, Junior High School Music Department to obtain air quality, energy, and subjective response data on an Automatic Variable Ventilation System. A control system with both CO2 and temperature inputs was devised to control the use of outdoor air. Infiltration measurements lead to a quantitative measure of ventil3tion efficiency. This in turn led to recommendations for air circulation patterns in rooms. The measured ventilation efficiency enabled energy and CO2 models to fit measured data. Energy savings of approximately 20% were found for this application. Subjective response of the occupants also was measured. A special questionnaire, subjected to statistical analysis, showed that the subjects felt warmer with increased CO2 in the room air. 相似文献
617.
We have adapted a procedure which was developed for studying the correlations in the distribution of genetic factors, such as sex ratios in siblings, to obtain estimates of the correlation between the number of mutagens and the number of nonmutagens in a sample. Positive correlations with correlation coefficients in excess of 0.8 were obtained. The high correlation suggests that it is possible to estimate the number of mutagens in samples with N > 100 compounds as (0.064 ± 0.01) N. 相似文献
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620.
The methane oxidation potential of several types of compost methanotrophic biofilter columns were compared in the laboratory over a period of 220 days. The results indicate an increase in methanotrophic activity over a period of about 100 days, up to a maximum of 400 g m(-2) day(-1), and a gradual decline to about 100 g m(-2) day(-1) within the next 120 days. High methane oxidation rates appear to be restricted to a small area of the column, 10-15 cm thick. Based on the laboratory investigations carried out to determine the cause for the decline in methane oxidation rate, it was concluded that the formation of exopolymeric substances (EPS), at the zones of maximum methane oxidation, was responsible for this decline. In monitoring methane oxidation in a column for up to 600 days, it was observed that mixing of the medium after formation of EPS enabled the column to temporarily recover high performance. The results suggest that stable, homogenous compost, with a low C/N and low ammonium content, mixed on a regular basis, could achieve and maintain high methane oxidation efficiencies. 相似文献