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731.
The price of fuelwood has been increasing at a rate higher than that of the consumer price index in most of the major urban centres of India. Today, in terms of cost per unit of energy delivered, fuelwood is more than twice as expensive as kerosene for cooking. This has immense public policy implications. A number of complementary policy interventions are needed so that forests can be saved and the stability of energy supplies can be achieved in developing countries.  相似文献   
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733.
ABSTRACT: The method of identifying dry stream reaches in carbonate terrane as surface indicators of potential ground-water reservoirs offers a valuable exploration technique that is more rapid and less expensive than traditional exploration methods involving random test drilling. In areas where dry stream reaches occur, subsurface drainage successfully competes with surface drainage, and sheet-like dissolution openings have developed parallel to bedding creating the ground-water reservoir. The occurrence and hydraulic characteristics of such reservoirs are highly variable, as attested to by the wide range of well yields. Union Hollow in south-central Tennessee is the setting for a case study that illustrates the application of the dry stream reach technique. In this technique, dry stream reach identification is based on two types of readily acquired information: (1) remotely sensed black and white infrared aerial photography; and (2) surface reconnaissance of stream channel characteristics. Test drilling in Union Hollow subsequent to identification of the dry reach proved that a localized ground-water reservoir was present.  相似文献   
734.
Efficient, economical treatment of mercury-contaminated soils and industrial wastes requires a treatment process that reduces mercury content to near background levels (<1 ppm) and recovers the removed mercury in pure recyclable form without producing liquid, solid, or gaseous secondary wastes. This article reviews the results achieved using a medium-temperature thermal desorption process developed and commercialized by Mercury Recovery Services, Inc. (MRS) that has successfully achieved these goals.  相似文献   
735.
Large but feasible increases that have been projected for the production of wood energy in the United States can be expected to significantly alter the current carbon storage patterns in US forest vegetation. The 1976 net wood increment left after forest cutting equals about 136 × 106 tons of carbon/year, with about 60% of the increment found in merchantable trees, and the remainder in nonmerchantable components.Achieving 5–10 quads of wood energy beyond 1976 levels by the year 2010 can significantly change current carbon storage patterns with the magnitude of change dependent on the extent of residue harvest to meet energy goals, and the rate of future forest growth. Complete loss of the apparent net wood increment is a possible outcome.Although the future growth and harvest situation cannot be known now, a range of possible scenarios suggests that US forests in the year 2010 will store much less carbon than today, thus significantly changing their role in the global carbon cycle.  相似文献   
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738.
After the Aznalcóllar mining spill (25th April 1998), considerable social concern arose amongst the inhabitants of the SW Iberian Peninsula concerning the consumption of local seafood. Squilla mantis was collected in four regions of the Gulf of Cádiz with a dual objective: to analyze the heavy metal levels for human consumption and as part of biomonitoring program. Heavy metal concentrations (Fe, Mn, Zn, Cu, Cd and Pb) were analyzed in soft tissues and cuticle. The highest values were found in the soft tissues for zinc, copper and cadmium and in the cuticle for iron, manganese and lead. The mean copper concentration in the soft tissue, corresponding to the edible part, was 27.1 microg x g(-1) wet weight. Approximately 80% of stations showed values higher than 20 microg x g(-1) wet weight of copper, the Spanish legal limit for the concentration of this metal in the crustacean for human consumption. For Zn and Cu no significant differences were found between regions, probably related with the capacity for regulation of S. mantis. The highest values found for copper in the Gulf of Cádiz compared to other areas is likely to be related with contamination from terrestrial mining activities (copper and pyrites) in the region, dating back to the times of Tartessians and Romans, rather than the effects of mining spill which was shown not to create any significant increases in heavy metal concentrations of organisms of the Guadalquivir River or the adjacent coastal area.  相似文献   
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The physical processes governing flow and pollutantdispersion at the neighbourhood scale, a spatial scaleintermediate between the street scale and the city scale, is notwell understood. Furthermore, it is not clear whether a traditional approach using averaged characteristics such as theaerodynamic roughness length is sufficient to predict the concentration field at this scale. To investigate pollutant dispersion in a real urban area, three field experiments were designed within the UK-URGENT programme sponsored by NERC. Theexperiments were performed in the City of Birmingham using a finite duration release of inert, non-toxic and non-depositingtracers, vis. perfluoromethylcyclohexane (PMCH) and perfluoromethylcyclopentane (PMCP). Measurements were taken using air bag samplers placedin an arc at 3.5 km (first experiment) and 1 km (second andthird experiments) from the source; some trap samplers wereplaced outside the main arc in the outskirts of the city. Measurements were analysed in the laboratory using anovel gas-chromatography technique. Data so obtained werecompared with predictions from a simple steady-state modeland a time-dependent model. The concentration-time serieswere very asymmetrical with a sharp rise, a plateau followedby a relatively slow decrease and finally a long-livedplateau above (or possibly very slow decrease to) thebackground level.  相似文献   
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