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341.
342.
Michael Bozsin 《Journal of the Air & Waste Management Association (1995)》2013,63(6):332-333
Air pollution abatement has been a constant concern for the ceramic indudry over the last four decades. The multiplicity of materials involved, numbering in the hundreds of fluxes and refractories for the manufacture of many different types of glasses, results in gaseous as well as particulate reaction products. Methods of abatement through various means have been developed and are in use in the United States and world-wide today. 相似文献
343.
344.
Bojidarka Ivanova Michael Spiteller 《Environmental science and pollution research international》2014,21(2):1548-1563
Since primary environmental concept for long storage of nuclear waste involved assessment of water in uranium complexes depending on migration processes, the paper emphasized solid-state matrix-assisted laser desorption/ionization (MALDI) mass spectrometric (MS) and IR spectroscopic determination of UO2(NO3)2·6H2O; UO2(NO3)2·3H2O, α-, β-, and γ-UO3 modifications; UO3·xH2O (x?=?1 or 2); UO3·H2O, described chemically as UO2(OH)2, β- and γ-UO2(OH)2 modifications; and UO4·2H2O, respectively. Advantages and limitation of vibrational spectroscopic approach are discussed, comparing optical spectroscopic data and crystallographic ones. Structural similarities occurred in α–γ modifications of UO3, and UO2(OH)2 compositions are analyzed. Selective speciation achieved by solid-state mass spectrometry is discussed both in terms of its analytical contribution for environmental quality assurance and assessment of radionuclides, and fundamental methodological interest related the mechanistic complex water exchange of UO3·H2O forms in the gas phase. In addition to high selectivity and precision, UV-MALDI-MS, employing an Orbitrap analyzer, was a method that provided fast steps that limited sample pretreatment techniques for direct analysis including imaging. Therefore, random and systematic errors altering metrology and originating from the sample pretreatment stages in the widely implemented analytical protocols for environmental sampling determination of actinides are significantly reduced involving the UV-MALDI-Orbitrap-MS method. The method of quantum chemistry is utilized as well to predict reliably the thermodynamics and nature of U–O bonds in uranium species in gas and condensed phases. 相似文献
345.
The diamond cartel has remained effective in controlling diamond supplies and prices for a longer period than any other major minerals cartel in the twentieth century. This paper examines the diamond pipeline from mine to the jewellery market. Particular attention is given to the characteristics of diamonds and of the industry structure that make the long-term stability of the cartel possible. The strategies of De Beers Consolidated Diamond Mines in controlling rough gem supplies and prices are examined, and projections are made to 2000. The paper shows that in spite of a projected decrease in the share of total diamond production sold through the De Beers' cartel in the 1990s, the cartel is expected to continue effectively to control supplies and prices. 相似文献
346.
Michael R. Palermo 《补救:环境净化治理成本、技术与工艺杂志》1991,1(4):473-492
This article describes the selection and field evaluation of dredging equipment and techniques for removal of highly contaminated sediments from the upper estuary of the Acusbnet River, a portion of the New Bedford Harbor Supetfund Project. Site conditions as related to dredge selection and operation, factors considered in selection of equipment, and various dredge types considered for use are described. Each of the dredge types is ranked according to the following criteria: availability, safety, potential for sediment resuspension, maneuverability, cleanup precision, cost and production, flexibility, required water depth for operation, ability to access the site, and compatibility with disposal options. A field pilot study comparing three dredge types indicated that dredging could be conducted at the site without a significant increase in the contaminant release from the upper estuary to the lower harbor. 相似文献
347.
Abundance of fecal caliform bacteria is a weak index of the presence of human pathogens in wastewater entering coastal waters.
In spite of this, use of fecal caliform indices for management purposes is widespread. To gain insight into interpretation
of fecal coliform data, we evaluated size of stocks of fecal coliforms in water, sediments, and sea wrack, in Buttermilk Bay,
a coastal embayment in Massachusetts. Sediments contained most of the fecal coliforms. Fecal coliforms in sediments were as
much as one order of magnitude more abundant than in the water column or in sea wrack. The fecal coliforms in sediments of
Buttermilk Bay were so abundant that resuspension of fecal coliforms from just the top 2 cm of muddy sediments could add sufficient
cells to the water column to have the whole bay exceed the federal limit of fecal coliforms for shellfishing.
The major sources of fecal coliforms to the bay were water-fowls, surface runoff, groundwater, and streams. Waterfowl were
the largest source of fecal coliforms during cold months; surface runoff, streams, and groundwater were most important during
warm months. Redirection of surface runoff pipes is unlikely to be a very successful management action since contributions
via this source are insufficient to account for the measured increases in concentrations of fecal coliforms in water. Removal
of waterfowl is also unlikely to be useful, since fecal coliform concentrations leading to closures of shellfish beds and
swimming areas are most frequent during warm months when waterfowl are rarest. Rates of loss of fecal caliform cells from
the water column by death and tidal exchange were high. Mortality of cells was about an order of magnitude larger than losses
by tidal exchange.
The amounts of fecal coliforms brought into the bay by waterfowl, surface runoff, groundwater, and streams are an order of
magnitude smaller than the losses by mortality and tidal removal. This implies that there is an additional source of fecal
coliforms within the bay. We suggest that resuspension of the upper layers of sediments can easily account for the fecal coliforms
present in the water.
Fecal coliform content of water and shellfish were not correlated. In contrast, sediment and shellfish fecal coliform abundances
were significantly related. Monitoring of fecal coliforms in sediments may provide a better assessment of shellfish than sampling
of water.
The large fecal coliform stock in sediments should be the first priority for management. Efforts ought to be directed toward
the reduction of sediment fecal coliform stocks. Lowering nutrient additions to coastal water bodies may be one practical
approach. 相似文献
348.
Environmental degradation, competition for resources, increasing food demands, and the integration of agriculture into the
international economy threaten the sustainability of many food production systems. Despite these concerns, the concept of
sustainable food production systems remains unclear, and recent attempts to appraise sustainability have been hampered by
conceptual inconsistencies and the absence of workable definitions. Six perspectives are shown to underpin the concept. Environmental
accounting identifies biophysical limits for agriculture. Sustained yield refers to output levels that can be maintained continuously.
Carrying capacity defines maximum population levels that can be supported in perpetuity. Production unit viability refers
to the capacity of primary producers to remain in agriculture. Product supply and security focuses on the adequacy of food
supplies. Equity is concerned with the spatial and temporal distribution of products dervied from resource use. Many studies
into sustainable agriculture cover more than one of these perspectives, indicating the concept is complex and embraces issues
relating to the biophysical, social, and economic environments. Clarification of the concept would facilitate the development
of frameworks and analytical systems for appraising the sustainability of food production systems.
LRRC Contribution No. 90–46. 相似文献
349.
350.
W. Michael. Aust Russ Lea James D. Gregory 《Journal of the American Water Resources Association》1991,27(1):111-116
ABSTRACT: A palustrine water tupelo (Nyssa aquatica L.)-baldcy-press (Taxodium distichum (L.) Rich.) swamp in southwestern Alabama was subjected to three types of disturbance, including helicopter logging, rubber-tired skidder logging simulation, and helicopter logging followed by an herbicide application. An adjacent undisturbed stand served as a control area. Post-harvest collection of sedimentation data revealed that the herbaceous and woody vegetation regrowth within the helicopter and skidded clearcut areas trapped more sediments than did the control or herbicide treatment areas. Clearcutting, followed by plant regrowth, improved the wet-land's capacity to remove sediments from overbank flow flood waters. 相似文献