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排序方式: 共有378条查询结果,搜索用时 31 毫秒
91.
This paper discusses the social science and engineering dimensions of search and rescue (SAR) in collapsed buildings. First, existing information is presented on factors that influence the behaviour of trapped victims, particularly human, physical, socioeconomic and circumstantial factors. Trapped victims are most often discussed in the context of structural collapse and injuries sustained. Most studies in this area focus on earthquakes as the type of disaster that produces the most extensive structural damage. Second, information is set out on the engineering aspects of urban search and rescue (USAR) in the United States, including the role of structural engineers in USAR operations, training and certification of structural specialists, and safety and general procedures. The use of computational simulation to link the engineering and social science aspects of USAR is discussed. This could supplement training of local SAR groups and USAR teams, allowing them to understand better the collapse process and how voids form in a rubble pile. A preliminary simulation tool developed for this purpose is described. 相似文献
92.
Hemdan Bahaa Ahmed El Nahrawy Amany Mohamed Mansour Abdel-Fatah M. Hammad Ali Belal Abou 《Environmental science and pollution research international》2019,26(10):9508-9523
Environmental Science and Pollution Research - We used a green sol–gel synthesis method to fabricate a novel nanoporous copper aluminosilicate (CAS) material. Nanoporous CAS was characterized... 相似文献
93.
Mohamed El Ghazali Benhamza Abdelhafid Brima Saddok Houda Noureddine Moummi 《International Journal of Sustainable Engineering》2017,10(2):82-89
Earth-air heat exchangers (EAHE) are devices used in the geothermal technique in order to reduce energy consumption in buildings. In this study, a simulation was conducted through the computational fluid dynamics platform FLUENT 6.3 for the prediction of thermal performance of the EAHE that describes the variation of the air temperature inside the tube. For this, it was necessary to design the heat exchanger while respecting the design and the actual dimensions of the experimental set-up, and stating that the temperature of the wall of the horizontal tube of the exchanger is equal to that of ground at 3 m depth. It should be noted that in assessing the temperature along the two sections vertical (input and output) of the exchanger, opting for a function (UDF) the user define function. Finally, noting a good agreement between both experimental and numerical study, and showing that a significant reduction in temperature at the outlet of the exchanger to a difference of 20 °C, confirming the effectiveness of the heat exchanger. 相似文献
94.
Heli Sirén Samira El Fellah 《Environmental science and pollution research international》2017,24(20):16765-16785
A novel analytical-scale concept to improve reliability of detection and analysis of natural and processed wastewater samples from a purification plant was developed. A sequential sample clean-up system of polymer-based octadecyl and silane-based quaternary amine sorbents were used for concentrating human based steroid hormones and their metabolites and detecting them by UV absorption with capillary electrophoresis (CE). The water samples were collected from influent and effluent processes of the water purification plant in Helsinki, Finland.The CE methods were partial-filling micellar electrokinetic chromatography and capillary zone electrophoresis. The analysis times and method concentration levels were optimized with eight steroids at the range of 0.5–10 mg/L. Since in CE the detectable quantities were higher than the existing amounts in the process waters, the real samples needed matrix removal combined with steroid enrichment. After 20,000-fold concentration testosterone-glucoside, androstenedione, progesterone, and estradiol-glucoside could be determined in the process water samples. The amounts of individual steroids in influent and effluent waters were 0–429 and 0–207 ng/L, respectively. Correspondently, their total amounts were 735 and 212 ng/L with excellent in day and inter-day repeatability. The RSD values were less than 1, 9.7, and 19% in repeated analyses, calculated from 60 analyses during 24 h, and from 130 analyses during 15 months, respectively. The steroid removal in purification process was 65% on average. The solid particles separated in three steps during the water clean-up concept contained 9.8–45 ng/g steroids in combined dry precipitates. 相似文献
95.
Life cycle assessment (LCA) is the standard technique used to make a quantitative evaluation about the ecological sustainability of a product or service. The life cycle inventory (LCI) data sets that provide input to LCA computations can express essential information about the operation of a process or production step. As a consequence, LCI data are often regarded as confidential and are typically concealed through aggregation with other data sets. Despite the importance of privacy protection in publishing LCA studies, the community lacks a formal framework for managing private data, and no techniques exist for performing aggregation of LCI data sets that preserve the privacy of input data. However, emerging computational techniques known as “secure multiparty computation” enable data contributors to jointly compute numerical results without enabling any party to determine another party’s private data. In the proposed approach, parties who agree on a shared computation model, but do not trust one another and also do not trust a common third party, can collaboratively compute a weighted average of an LCA metric without sharing their private data with any other party. First, we formulate the LCA aggregation problem as an inner product over a foreground inventory model. Then, we show how LCA aggregations can be computed as the ratio of two secure sums. The protocol is useful when preparing LCA studies involving mutually competitive firms. 相似文献
96.
Mohamed Kaddari Mahmoud El Mouden Abdelowahed Hajjaji 《International Journal of Green Energy》2017,14(10):839-844
This paper presents potential energy savings by installing high-efficiency motors instead of existing ones and their impact on greenhouse gases emissions reductions. This research study of the energy efficiency of electric motors has been performed in a typical thermal power plant. In the literature, the focus has been mainly on separate and away electric motors from operating facilities. The important advantage of this paper over other studies is that it uses the actual motors’ efficiency in the evaluation. The gains both in terms of electrical energy savings and in terms of financial economy by using high-efficiency motors have been discussed. As a result, the energy saving can be expected as 12.6% at the operating rate. This excellent result also reduces greenhouse gas emission by 1,423 tons every year. The analysis of the data provided an overview on energy losses often generated by the degradation and rewinding of electrical motors. This study represents very encouraging results that will help energy managers of industrial plants to become more involved in energy efficiency strategies. 相似文献
97.
Riham R. Mohamed Nadia A. Rizk Bothaina M. Abd El Hady Heba M. Abdallah Magdy W. Sabaa 《Journal of Polymers and the Environment》2017,25(3):667-682
Crosslinked carboxymethyl chitosan (CMCh)/poly(ethylene glycol) (PEG) nanocomposites were synthesized using terephthaloyl diisothiocyanate as a crosslinking agent, in presence of montmorillonite (MMT), in different weight ratios of the two matrices. Characterization of nanocomposites was performed using different analyses. Swelling behavior was studied in different buffered solutions. It was found that formation of crosslinked CMCh/PEG nanocomposites increased the swell ability. Metal ions adsorption had also been investigated. The results indicated that crosslinked CMCh adsorbs various metal ions much more than non-crosslinked CMCh. Antimicrobial activity was examined against Gram-positive bacteria (S. aureus (RCMB 010027) and S. Pyogens (RCMB 010015), Gram-negative bacteria (E. coli (RCMB 010056), and also against fungi (A. fumigates (RCMBA 02564, G. candidum (RCMB 05096) and C. albicans (RCMB 05035). Data indicated that most of these nanocomposites exhibited good antimicrobial potency. Degradation studies were carried out in simulated body fluid for different time periods in order to find out the degradation index. Results showed that weight loss (%) of most of the nanocomposites increased as a function of incubation time. 相似文献
98.
Maftouh Abderrahim El Fatni Omkaltoume Bouzekri Siham Rajabi Fateme Sillanpää Mika Butt Muhammad Hammad 《Environmental science and pollution research international》2023,30(2):2341-2354
Environmental Science and Pollution Research - Due to disparities in the allocation of rainwater and drought, extreme exploitation of groundwater reservoirs has depleted water supplies in many... 相似文献
99.
This work aims to determine the maximum concentration and downwind distance at the earth's surface in two methods Briggs and standard for two conditions are slightly unstable and neutral by using the Gaussian equation at different effective heights and wind seeped at (8.9, 8.5 and 8 m/s) under lateral and vertical dispersion coefficient measurement. 相似文献
100.
Distribution and Statistical Analysis of Leachable and Total Heavy Metals in the Sediments of the Suez Gulf 总被引:3,自引:0,他引:3
The concentrations of nine heavy metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pd and Zn) in the labile and total fractions of muddy
and sandy sediment samples collected from twelve sites in Suez Gulf during April 1999 were studied to evaluate the pollution
status of the Suez Gulf. The enrichment factors (EF) for each element were calculated. There are extremely high concentrations
of Cd, Ni, Pb and slightly concentration of Cr and Cu in both muddy and sandy sediments. The concentration of Zn was moderately
high and can be considered as seriously contaminate Metal pollution index (MPI) shows high values ranged between 46 to 156
and 40 to 232 for both sandy and muddy sediments, respectively. Concentrations of heavy metals were normalized against iron
for total fraction in both of sandy and muddy sediments. Principal component analysis (PCA) was studied on the data matrix
obtained and represented three-factor model explaining 92.22% for labile and 88.82% for total fractions of muddy sediment.
The main source of contamination is the offshore oil fields and industrial wastes. This is largely a result of ineffective
and inefficient operation equipment, illegal discharge of dirty ballast water from tankers and lack of supervision and prosecution
of offenders. 相似文献