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   47篇
  免费   0篇
  国内免费   3篇
安全科学   1篇
废物处理   5篇
环保管理   4篇
综合类   5篇
基础理论   3篇
污染及防治   20篇
评价与监测   9篇
社会与环境   2篇
灾害及防治   1篇
  2022年   2篇
  2021年   6篇
  2019年   2篇
  2018年   3篇
  2017年   2篇
  2016年   2篇
  2015年   4篇
  2014年   2篇
  2013年   10篇
  2012年   4篇
  2011年   3篇
  2008年   1篇
  2007年   1篇
  2006年   1篇
  2005年   1篇
  2004年   1篇
  2003年   1篇
  2002年   2篇
  2000年   1篇
  1996年   1篇
排序方式: 共有50条查询结果,搜索用时 531 毫秒
21.

Production of Scenedesmus sp. biomass in chicken slaughterhouse wastewater (CSWW) is a promising alternative technique for commercial culture medium due to the high nutritional content of the generated biomass to be used as fish feeds. The current work deals with optimising of biomass production in CSWW using response surface methodology (RSM) as a function of two independent variables, namely temperature (10–30 °C) and photoperiod (6–24 h). The potential application of biomass yield as fish feeds was evaluated based on carbohydrate, protein and lipid contents. The results revealed that the best operating parameters for Scenedesmus sp. biomass production with high contents of carbohydrates, proteins and lipids were determined at 30 °C and after 24 h. The actual and predicted values were 2.47 vs. 3.09 g, 1.44 vs. 1.27 μg/mL, 29.9 vs. 31.60% and 25.75 vs. 28.44%, respectively. Moreover, the produced biomass has a high concentration of fatty acid methyl ester (FAME) as follows: 35.91% of C15:1; 17.58% of C24:1 and 14.11% of C18:1N9T. The biomass yields have 7.98% of eicosapentaenoic acid (EPA, C20:5N3) which is more appropriate as fish feeds. The Fourier transform infrared (FTIR) analysis of biomass revealed that the main functional groups included hydroxyl (OH), aldehyde (=C–H), alkanes and acyl chain groups. Scanning electron micrograph (SEM) and energy-dispersive X-ray spectroscopic analysis (EDS) indicated that the surface morphology and element distribution in biomass produced in BBM and CSWW were varied. The findings have indicated that the biomass produced in CSWW has high potential as fish feeds.

  相似文献   
22.
The pivot point of delta in Tarbela dam has reached at about 10.6 km from the dam face which may result in blocking of tunnels. Tarbela delta was modeled from 1979 to 2060 using hec-6 model. Initially, the model was calibrated for year 1999 and validated for years 2000, 2001, 2002, and 2006 by involving the data of sediment concentration, reservoir cross sections (73 range lines), elevation-area capacity curves, and inflows and outflows from the reservoir. Then, the model was used to generate future scenarios, i.e., run-1, run-2, and run-3 with pool levels; 428, 442, and 457 m, respectively, till 2060. Results of run-1 and run-2 showed advancement to choke the tunnels by 2010 and 2030, respectively. Finally, in run-3, the advancement was further delayed showing that tunnels 1 and 2 will be choked by year 2050 and pivot point will reach at 6.4 km from the dam face.  相似文献   
23.
SUMMARY

Solid household waste management in Malaysia has reached a critical stage. Increasing population, urbanization and changing patterns of lifestyle have instigated the phenomenon. The 15 000 tonnes of garbage produced daily are thrown into 230 landfills nationwide, where 80% of them have only two years of life span left. Although recycling programmes were launched as early as 1990, only 5% of the wastes are recycled. The purpose of the present research was to ascertain the current management of household solid waste, attitude and motivational factors towards recycling. Data were collected using interview survey on 150 households in an urban residential area. The findings demonstrated that the respondents had very low awareness and knowledge regarding local domestic waste management. Separation of organic and non-organic wastes was rarely practised by 76% of the respondents. Most waste was thrown away, except for newspaper and aluminium cans which were regularly recycled, while furniture, and electrical items were reused by giving away or trading-in. The attitude of the respondents towards recycling was modest. Of the five motivational factors, intrinsic satisfaction and individual commitment were more important reasons for recycling than convenience, economic motivation and societal commitment. The results of the study indicated that, in order to overcome the solid waste crisis, the conscience of the individual needs to be raised through environmental awareness and concern, inculcation of sustainable consumption practices and education on waste management.  相似文献   
24.
Fine PM measurements: personal and indoor air monitoring   总被引:3,自引:0,他引:3  
This review compiles personal and indoor microenvironment particulate matter (PM) monitoring needs from recently set research objectives, most importantly the NRC published "Research Priorities for Airborne Particulate Matter (1998)". Techniques and equipment used to monitor PM personal exposures and microenvironment concentrations and the constituents of the sampled PM during the last 20 years are then reviewed. Development objectives are set and discussed for personal and microenvironment PM samplers and monitors, for filter materials, and analytical laboratory techniques for equipment calibration, filter weighing and laboratory climate control. The progress is leading towards smaller sample flows, lighter, silent, independent (battery powered) monitors with data logging capacity to store microenvironment or activity relevant sensor data, advanced flow controls and continuous recording of the concentration. The best filters are non-hygroscopic, chemically pure and inert, and physically robust against mechanical wear. Semiautomatic and primary standard equivalent positive displacement flow meters are replacing the less accurate methods in flow calibration, and also personal sampling flow rates should become mass flow controlled (with or without volumetric compensation for pressure and temperature changes). In the weighing laboratory the alternatives are climatic control (set temperature and relative humidity), and mechanically simpler thermostatic heating, air conditioning and dehumidification systems combined with numerical control of temperature, humidity and pressure effects on flow calibration and filter weighing.  相似文献   
25.
In conjunction with a nationwide motorcycle safety program, the provision of exclusive motorcycle lanes has been implemented to overcome link-motorcycle accidents along trunk roads in Malaysia. However, not much work has been done to address accidents at junctions involving motorcycles. This article presents the development of predictive model for motorcycle accidents at three-legged major-minor priority junctions of urban roads in Malaysia. The generalized linear modeling technique was used to develop the model. The final model reveals that motorcycle accidents are proportional to the power of traffic flow. An increase in nonmotorcycle and motorcycle flows entering the junctions is associated with an increase in motorcycle accidents. Nonmotorcycle flow on major roads had the highest effect on the probability of motorcycle accidents. Approach speed, lane width, number of lanes, shoulder width, and land use were found to be significant in explaining motorcycle accidents at the three-legged major-minor priority junctions. These findings should enable traffic engineers to specifically design appropriate junction treatment criteria for nonexclusive motorcycle lane facilities.  相似文献   
26.
The Urban Farming Movement is relatively young in Louisville, Kentucky but it seems to be off to a good start. Being in its earliest stages, assessments of this effort must be made cautiously, even tentatively. Examining a movement that is in progress requires a study of the state's land use and segregation policies, both of which have been dynamic in Kentucky. Further, this study is also relevant as there is a growing convergence of national and regional attitudes towards American obesity, while there are competing notions of food preference and food choice. All of which are influenced by racial politics, and there is a deep concern regarding food security. Considering all of these, it is necessary to examine the Government's efforts to address obesity/food imbalance in a variety of settings, especially where urban farming is expanding, such as Chicago and Detroit. In New York, roof-top gardens dot the landscape and the urban farm movement is largely a “success”. So, city leaders have chosen to address another health issue – trans fat. Rather than joining the food choice/preference debate by banning fast-food restaurants, city leaders have chosen to enact a trans-fat ban. Unpopular at first, other cities and states have followed, and the Federal Government will mandate a trans-fat ban this year. In Louisville, Chicago and Detroit, where the trans-fat bans did not succeed, the urban farm movement may be the primary means of addressing malnutrition, in the form of obesity.  相似文献   
27.
Slope failure has become a major concern in Malaysia due to the rapid development and urbanisation in the country. It poses severe threats to any highway construction industry, residential areas, natural resources and tourism activities. The extent of damages that resulted from this catastrophe can be lessened if a long-term early warning system to predict landslide prone areas is implemented. Thus, this study aims to characterise the relationship between Oxisols properties and soil colour variables to be manipulated as key indicators to forecast shallow slope failure. The concentration of each soil property in slope soil was evaluated from two different localities that consist of 120 soil samples from stable and unstable slopes located along the North-South Highway (PLUS) and East-West Highway (LPT). Analysis of variance established highly significant difference (P < 0.0001) between the locations, the total organic carbon (TOC), soil pH, cation exchange capacity (CEC), soil texture, soil chromaticity and all combinations of interactions. The overall CIELAB analysis leads to the conclusion that the CIELAB variables lightness L*, c* (Chroma) and h* (Hue) provide the most information about soil colour and other related soil properties. With regard to the relationship between colour variables and soil properties, the analysis detected that soil texture, organic carbon, iron oxide and aluminium concentration were the key factors that strongly correlate with soil colour variables at the studied area. Indicators that could be used to predict shallow slope failure were high value of L*(62), low values of c* (20) and h* (66), low concentration of iron (53 mg kg?1) and aluminium oxide (37 mg kg?1), low soil TOC (0.5%), low CEC (3.6 cmol/kg), slightly acidic soil pH (4.9), high amount of sand fraction (68%) and low amount of clay fraction (20%).  相似文献   
28.
Produced water is water trapped in underground formations that is brought to the surface along with oil or gas production. Oilfield impacted soil is the most common environmental problem associated with oil production. The produced water associated with oil-production contaminates the soil and causes the outright death of plants, and the subsequent erosion of topsoil. Also, impacted soil serves to contaminate surface waters and shallow aquifers. This paper is intended to provide an approach for full characterization of contaminated soil by produced water, by means of analysis of both the produced water and the impacted soil using several recommended analytical techniques and then identify and assay the main constituents that cause contamination of the soil. Gialo-59 oilfield (29N, 21E), Libya, has been chosen as the case study of this work. The field has a long history of petroleum production since 1959, where about 300,000 bbl of produced water be discharged into open pit. Test samples of contaminated soil were collected from one of the disposal pits. Samples of produced water were collected from different points throughout the oil production process, and the analyses were carried out at the labs of Libyan Petroleum Institute, Tripoli, Libya. The results are compared with the local environmental limiting constituents in order to prepare for a plan of soil remediation. The results showed that the main constituents (pollutants) that impact the soil are salts and hydrocarbon compounds. Accordingly; an action of soil remediation has been proposed to remove the salts and degradation of hydrocarbons.  相似文献   
29.
Environmental Science and Pollution Research - Owing to the ever-increasing demand for food, the growing global population has forced farmers to increase fertilizer use. The overall use of...  相似文献   
30.
Recent monitoring investigations have shown that antimicrobial agents used in veterinary medicine can cause non-point source contamination of soils through manure spreading. In the present study, the effect of the antimicrobial agent sulfamethazine (sulfadimidine) on degradation and sorption of the herbicide metolachlor in a sandy loam soil was studied. In soil samples treated with sulfamethazine at two concentrations (15 and 150 microg kg(-1) soil), metolachlor persistence was not different than of that observed in untreated samples. These results were supported by the absence of effects of both sulfamethazine concentration levels on the size of the culturable soil bacteria population. Equilibrating soil samples with metolachlor solutions containing equivalent sulfamethazine concentrations did not lead to any significant effects on metolachlor sorption, suggesting that, under the conditions of the present experiment, sulfamethazine did not affect metolachlor bioavailability in soil. This laboratory investigation showed that concentrations of sulfamethazine in the microg kg(-1) range did not cause significant effects on metolachlor degradation and sorption thus not affecting the main processes ruling its environmental fate in soil.  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