首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   19篇
  免费   0篇
安全科学   1篇
环保管理   5篇
综合类   1篇
基础理论   4篇
污染及防治   5篇
评价与监测   3篇
  2019年   1篇
  2017年   1篇
  2016年   1篇
  2013年   2篇
  2011年   2篇
  2010年   2篇
  2009年   1篇
  2008年   3篇
  2007年   1篇
  2006年   1篇
  2004年   3篇
  2002年   1篇
排序方式: 共有19条查询结果,搜索用时 31 毫秒
1.
Real‐time flood inundation mapping is vital for emergency response to help protect life and property. Inundation mapping transforms rainfall forecasts into meaningful spatial information that can be utilized before, during, and after disasters. While inundation mapping has traditionally been conducted on a local scale, automated algorithms using topography data can be utilized to efficiently produce flood maps across the continental scale. The Height Above the Nearest Drainage method can be used in conjunction with synthetic rating curves (SRCs) to produce inundation maps, but the performance of these inundation maps needs to be assessed. Here we assess the accuracy of the SRCs and calculate statistics for comparing the SRCs to rating curves obtained from hydrodynamic models calibrated against observed stage heights. We find SRCs are accurate enough for large‐scale approximate inundation mapping while not as accurate when assessing individual reaches or cross sections. We investigate the effect of terrain and channel characteristics and observe reach length and slope predict divergence between the two types of rating curves, and SRCs perform poorly for short reaches with extreme slope values. We propose an approach to recalculate the slope in Manning’s equation as the weighted average over a minimum distance and assess accuracy for a range of moving window lengths.  相似文献   
2.
Formulation of standards of quality in parks and outdoor recreation can be guided by normative theory and related empirical methods. We apply this approach to measure the acceptability of a range of use levels in national parks in Turkey and the United States. Using statistical methods for comparing norm curves across contexts, we find significant differences among Americans, British, and Turkish respondents. In particular, American and British respondents were substantially less tolerant of seeing other visitors and demonstrated higher norm intensity than Turkish respondents. We discuss the role of culture in explaining these findings, paying particular attention to Turkey as a traditional “contact culture” and the conventional emphasis on solitude and escape in American environmental history and policy. We conclude with a number of recommendations to stimulate more research on the relationship between culture and outdoor recreation.  相似文献   
3.
The objective of this study was to determine the dust concentrations in selected tractor and combine operations in eastern Mediterranean region in Turkey Mean dust concentrations were 137.9 mg m(-3), 83.6 mg m(-3), 80.3 mg m(-3), and 88.8 mg m(-3) respectively for soil packing, furrowing, straw making, and baling on tractors with no cabins whereas 106.9 mg m(-3) was found in combines without cabins, which are much higher than the limit dust concentration (10 mg m(-3)) considered hazardous for workers' health. In tractor operations with field-installed cabins, mean dust concentrations were 5.6 mg m(-3), 6.6 mg m(-3), 6.4 mg m(-3), and 3.7 mg m(-3), respectively in soil packing, furrowing, straw making, and baling while 4.7 mg m(-3) was measured in combines with field-installed cabins. Considering unit-manufactured cabins, mean dust concentrations were 1.1 mg m(-3), 1.6 mg m(-3), 3.2 mg m(-3), and 1.4 mg m(-3) respectively in tractor operations, and 1.4 mg mr(-3) in combine operations. Variance analyses showed that not only the respiration environment of the workers but also the field operation had a significant effect on measured dust concentrations (p < 0.01). Pearson correlation coefficient was 0.74 (very strong level) between dust concentration and wind speed in soil packing, 0.46 (medium level) between dust concentration and wind speed in baling, and 0.44 (medium level) between dust concentration and ground speed in combining.  相似文献   
4.
The main objective of this study is to generate a knowledge base which is composed of user-defined variables and included raster imagery, vector coverage, spatial models, external programs, and simple scalars and to develop an expert classification using Landsat 7 (ETM+) imagery for land cover classification in a part of Trabzon city. Expert systems allow for the integration of remote-sensed data with other sources of geo-referenced information such as land use data, spatial texture, and digital elevation model to obtain greater classification accuracy. Logical decision rules are used with the various datasets to assign class values for each pixel. Expert system is very suitable for the work of image interpretation as a powerful means of information integration. Landsat ETM data acquired in the year 2000 were initially classified into seven classes for land cover using a maximum likelihood decision rule. An expert system was constructed to perform post-classification sorting of the initial land cover classification using additional spatial datasets such as land use data. The overall accuracy of expert classification was 95.80%. Individual class accuracy ranged from 75% to 100% for each class.  相似文献   
5.
The increasing use of ozone in water disinfection processes has been the focus of considerable concern in regards to inorganic disinfection by product formation of bromate in waters containing bromide. Due to the public health risk caused by the presence of bromate as a suspected carcinogen, attention had been addressed to the conditions under which bromate is formed. In this study, photoanodic bromine generation and bromate (BrO(3)(-)) formation were investigated using a TiO(2) electrode in a photoelectrocatalytic (PEC) treatment process. The separation of anodic and cathodic reactions in the PEC system resulted in a pH decrease from 9.3 to 3.0 in the photoanode compartment and an increase to 11.0 in the cathode compartment. Under a photo-illumination intensity of 5.7 m W cm(-2) UV, a biasing potential of +1.0V vs SCE, a pH of 6.0 and at a NaBr concentration of 1.0 x 10(-2) M, active bromine formation increased over time with 2.4 x 10(-6) M min(-6) rate and reached a steady-state concentration of 1.44 x 10(-4) M in 60 min. Bromate formation was detected after a lag-period of 15 min and exhibited a continuous increasing trend with respect to irradiation time. No bromate formation was observed below pH 6.5 whereas an increasing bromate concentrations and pH up to pH=8.5 were noted.  相似文献   
6.
Arsenic (As) is a metalloid that poses serious environmental threats due to its behemoth toxicity and wide abundance. The use of arsenic-contaminated groundwater for irrigation purpose in crop fields elevates arsenic concentration in surface soil and in the plants. In many arsenic-affected countries, including Bangladesh and India, rice is reported to be one of the major sources of arsenic contamination. Rice is much more efficient at accumulating arsenic into the grains than other staple cereal crops. Rice is generally grown in submerged flooded condition, where arsenic bioavailability is high in soil. As arsenic species are phytotoxic, they can also affect the overall production of rice, and can reduce the economic growth of a country. Once the foodstuffs are contaminated with arsenic, this local problem can gain further significance and may become a global problem, as many food products are exported to other countries. Large-scale use of rainwater in irrigation systems, bioremediation by arsenic-resistant organisms and hyperaccumulating plants, and the aerobic cultivation of rice are some possible ways to reduce the extent of bioaccumulation in rice. Investigation on a complete food chain is urgently needed in the arsenic-contaminated zones, which should be our priority in future researches.  相似文献   
7.
Cakirogullari GC  Secer S 《Chemosphere》2011,85(11):1713-1718
The concentrations of indicator polychlorinated biphenyls (PCBs) and organochlorine insecticides were determined in bonito (Sardasarda L. 1758) and anchovy (Engraulisencrasicolus L. 1758) from the Black Sea, Turkey. Concentrations of total indicator PCBs ranged between <1-17.0 in bonito, and <1-17.5 ng/g fresh weight in anchovy, and total of 1,1,1-trichloro-2,2-bis-chlorophenyl-ethane and its metabolites’ (DDTs) concentrations ranged between 13.4-26.3, and 2.96-19.0 ng/g fresh weight in bonito and anchovy respectively. PCB 52, p,p′-DDE and endosulfan (α + β) were found dominant in both of the fish species. Except endosulfan, and some DDT metabolites, none of the studied organochlorine pesticides was detected in the fish samples. Concentrations of PCBs in anchovy were found higher than those in bonito, whereas DDT and endosulfan concentrations were found similar in both of the fish species. All of the fish samples had residue concentrations below the maximum residue limits (MRL) recommended by FAO/WHO Codex Alimentarius Commission.  相似文献   
8.
Selcuk H  Bekbolet M 《Chemosphere》2008,73(5):854-858
In this study, photocatalytic (PC) and photoelectrocatalytic (PEC) treatment methods were comparatively investigated as a possible means of removing humic acid (HA) following absorbance at 254nm (UV(254)) and total organic carbon (TOC) analysis. The enhanced HA degradation rates were obtained in the PEC system over the conventional PC process under acidic, neutral and alkaline conditions. Preliminary and binary experiments were performed to determine the selectivity of the photoanode in terms of HA and chloride oxidation. TOC, chlorine and photocurrent parameters proved that HA was selectively removed before chlorine generation. The inhibitory effect of carbonate ions on the performance of photoanode was also studied under different pH values.  相似文献   
9.
10.
Striped hyenas (Hyaena hyaena L.) are one of the large carnivores whose numbers have rapidly decreased in Turkey. To monitor and assess the distribution of striped hyenas in Mediterranean region of Turkey, geographical information systems (GIS) and remote sensing technologies were implemented. For this purpose, the GIS database was generated and digital maps were produced in ArcGIS 9.2 program, considering some of the main factors including signs of striped hyenas, elevation, slope, land use types, feeding sources, and road network. The land use types in the distribution area of striped hyenas were classified by using ERDAS Imagine program. The results from the land use classification indicated that the signs of striped hyenas mostly distributed over the agricultural areas especially with olive groves, and followed by maquis. It was found that there was a spatial relationship between the signs of striped hyenas and feeding sources such as organic waste centers and a chicken farm in the region.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号