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101.
Regional Environmental Change - This study examines the change in climate variables and snow cover dynamics and their impact on the hydrological regime of the Jhelum River basin in Western...  相似文献   
102.
Poly(l-lactic acid) (PLLA)/poly(caprolactone) (PCL) and two types of organoclay (OMMT) including a fatty amide and ocatdecylamine montmorillonite (FA-MMT and ODA-MMT) were employed to produce polymer nanocomposites by melt blending. Materials were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), elemental analysis, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Mechanical properties were also investigated for these nanocomposites. The nanocomposites showed increasing mechanical properties and thermal stability. XRD results indicated that the materials formed nanocomposites. SEM morphology showed that increasing content of OMMT reduced the domain size of phase separated particles. TEM outcomes have confirmed the intercalated type of nanocomposite. Additionally, a solution casting process has been used to prepare these nanocomposites and characterized to compare these results with the above process.  相似文献   
103.
露天矿生产爆破,特别是靠帮爆破在边坡中形成的爆破损伤区对其稳定性具有很大的影响。本文针对大孤山铁矿露天爆破开采的实际情况,建立了极限平衡数值分析模型及峰值速度衰减公式。利用数值分析软件Geoslope对边坡靠帮爆破过程中岩体损伤范围进行了研究,主要分析了在爆破-200--212m水平时,爆破震动对边坡岩体的影响,并利用萨道夫斯基公式和PPV安全判据对爆区周围岩体损伤范围进行了计算。结果表明距离炮孔6.2m以内范围为完全破碎区,6.2-12.4m为岩体重度损伤区,12.4-19.7m为轻微损伤区。数值分析表明距爆源同一距离的岩体质点峰值速度随深度的增加而减小,爆破区周围震动波速成漏斗形分布,同实际爆破情况吻合。  相似文献   
104.
The present study aims to examine the physiological, biochemical and defence system responses of Calotropis procera to vehicle exhaust pollution. We selected various sample sites along two major roads in the Punjab province of Pakistan, i.e. Faisalabad to Sargodha road (FSR) and Pindi Bhattian to Lillah motorway (M-2). Traffic density at all sites and plant responses (i.e. chlorophyll a, chlorophyll b, total chlorophyll and carotenoid contents, transpiration rate, stomatal conductance, photosynthetic rate, sub-stomatal CO2 concentration, water use efficiency, total free amino acids, total soluble proteins and total antioxidant activity) were measured. Levels of carbon (C) and nitrogen (N) and four metals of most possible concern – i.e. lead (Pb), zinc (Zn), cadmium (Cd) and nickel (Ni) – were also examined in all samples. We found their considerable deposition in all the samples along roads. Inhibitory effects of roadside pollutants were noted for photosynthetic pigments, stomatal conductance, transpiration rate, photosynthetic rate and total soluble proteins, whereas stimulatory effects were noted for sub-stomatal CO2 concentration, free amino acids and total antioxidant activity. The stimulation of antioxidant enzymes activity revealed stress and mitigation of reactive oxygen species. The present study clearly signifies that C. procera has great potential to endure the stress caused by roadside pollutants.  相似文献   
105.
ABSTRACT: A critical examination of the techniques used to assess and specify environmental instream flow requirements is provided. The strengths and weaknesses of individual techniques are evaluated on both an absolute and a comparative basis. Particular attention is given to the problem of specifying environmental flow requirements in Australia where the hydrology has distinctly different characteristics to those in countries where most of the models for prediction of instream flow requirements were developed. Broad recommendations as to the suitability and use of the different techniques for different conditions are provided.  相似文献   
106.
The aim of this study is to identify management practices that effectively reduce greenhouse gas (GHG) emissions with regard to the green supply chain adopted by mobile phone producers. Six cases were surveyed (Apple, Samsung, LG, Huawei, Nokia, and ZTE). The main source of data was sustainability reports, which were retrieved from the Global Reporting Initiative database. A special data analysis technique called rank analysis was adopted. The results revealed that the effective practices to reduce GHG 1 emissions were related to production process and business travel; those that were effective for reducing GHG 2 emissions were related to facilities accreditation and energy saving; and those effective in reducing GHG 3 emissions were related to logistics and customer practices. No effective actions related to the management of relationships with suppliers were identified by this study. Indicative models for the relationship between actions and GHG emissions were developed, as was a value‐stream map. The previous studies reporting the effective practices in other industries reported results for reducing GHG 1 or GHG 3, or overall GHG emissions, without discriminating among the actions taken to reduce such emissions, although some limited actions were reported. This study describes the effective practices along the whole supply chain—both upstream and downstream—and it also lists the actions related to addressing all the emissions, whether GHG 1, 2, or 3.  相似文献   
107.
Alzanzalakhet, Melia azedarach L. (Sapindales: Meliaceae) is a common medicinal plant which is found in Hail desert in Saudi Arabia and traditionally used for various purposes. In this study, toxin effectiveness of the ethanolic, acetonic, and aqueous extracts of M. azedarach leaves was tested to determine a larvicidal activity against the cucurbit fly, Dacus ciliatus (Loew) (Diptera: Tephritidae). Different treatments with M. azedarach extracts varied significantly in their impact on mortality of D. ciliatus larvae. Results showed that all tested extracts in the three solvents exerted a positive pattern for reducing larvae of D. ciliatus. However, the ethanolic M. azedarach extract was the most potent compared with other tested solvents. The highest mortality of the D. ciliatus larvae was shown to be 94%, 74%, and 68% when the concentration was 1?×?105?ppm for ethanolic, acetonic, and aqueous extracts, respectively. In contrast, the concentration 1?×?101?ppm resulted in the lowest mortality of D. ciliatus larvae at 40%, 34%, and 12% for ethanolic, acetonic, and aqueous extracts, respectively. Overall, the results of this study suggest that the ethanolic extract of M. azedarach leaves may be used as a sustainable method for controlling D. ciliatus larvae.  相似文献   
108.
Environmental Science and Pollution Research - This study aims to evaluate the environmental performance of small and medium-sized enterprises (SMEs) through green human resource...  相似文献   
109.
厦门西海域综合整治后表层沉积物污染状况   总被引:1,自引:0,他引:1  
根据2003年11月的厦门西海域表层沉积物污染状况的现场调查资料,对2002年综合整治后厦门西海域重金属含量及异养细菌、粪大肠肝菌等的分布特点进行了研究。结果表明,厦门西海域表层沉积物中Cu、Zn、As含量的平均值分别为:67.4、283.8、9.8×10-6(干重),各站位沉积物中的Cu、Zn离子含量都超标。员当湖排污口附近的污染最为严重,粪大肠杆菌、弧菌、多环芳烃降解菌和油脂降解菌数都为最高值,在沉积物样品中分别可达到490/g、3.3×103/g、1.5×105/g、5×104/g。  相似文献   
110.
In the present paper, seven heavy metals (Pb, Cd, Ni, Cu, Zn, Cr and Fe) in canned salmon, sardine and tuna fish were determined by using atomic absorption spectroscopy. Cadmium and lead levels were determined by graphite tube AAS whereas Ni, Cu, Cr and Fe were determined by flame AAS. Analytical results were validated by spiking the samples with various concentrations of these metals for recovery. The metal contents, expressed in μg/g, wet weight, varied depending upon the specie studied. The levels of Pb ranged from 0.03–1.20 μg-g−1 with an average of 0.313 μg-g−1 for salmon; 0.03–0.51 μg-g−1 with an average of 0.233 μg-g−1 for tuna and 0.13–1.97 μg-g−1 with an average of 0.835 μg-g−1 for sardines. The levels of Cd ranged from 0.02–0.38 μg-g−1 with an average of 0.161 μg-g−1 for salmon; 0.07–0.64 μg-g−1 with an average of 0.227 μg-g−1 for tuna and 0.010–0.690 μg-g−1 with an average of 0.183 μg-g−1 for sardines. Comparative evaluation of these metals in three varieties of fish showed that average concentration of lead in sardines is about 4 times and Ni about 3 times higher as compared to tuna. Generally, the levels of these metals follow the order sardine > salmon > tuna. The data generated in the present study compared well with the similar studies carried out in different parts of the world. The results indicate that canned fish, in general and tuna in particular, have concentrations within permissible limits of WHO/FAO levels for these heavy metals. Therefore, their contribution to the total body burden of these metals can be considered as negligibly small.  相似文献   
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