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1.
This paper uses an incremental mode-superposition procedure to compute the inelastic dynamic response of multi-degree-of-freedom systems. A damping matrix proportional to the instantaneous properties is used throughout the analysis. The non-linear response of several shear type plane and space frames with elastic-plastic and bilinear column properties subjected to ground excitation was computed by both the incremental mode-superposition and the direct integration of the coupled equations of motion. When all modes are considered, the responses computed by the incremental mode-superposition are identical to those from the direct integration. Fewer modes can also be used to compute the response with reasonable accuracy by performing the modal truncation for each time increment. The study shows that incorporating instantaneous damping in non-linear dynamic analysis is relatively simple and requires less computational time than the direct integration. 相似文献
2.
Kinetics and Equilibrium Sorption Studies of 4-Nitrophenol on pyrolyzed and activated oil shale residue 总被引：1，自引：0，他引：1
Sorption of the organic pollutant 4-nitrophenol (4-NP) by pyrolyzed and activated Jordanian oil-shale was studied. Pyrolyzed oil shale was prepared using a fluidized bed reactor at 520 °C in the presence of nitrogen. Physical activation was carried out by treating the pyrolyzed oil shale with CO2 at 830 °C, while chemical activation was achieved by using KOH and ZnCl2 as impregnating agents. Batch kinetics and isotherm studies were conducted to evaluate the sorption process. Effects of contact time, initial sorbate concentration, sorbent concentration, temperature, pH and inorganic salts (NaCl and KCl) on the sorption process by the different sorbents were considered. Chemically activated oil shale, pretreated with ZnCl2, gave the highest uptake of 4-NP. The isotherm experimental data fit reasonably well to Langmuir, Freundlich and Redlich-Paterson models. Three kinetic models, namely the Morris-Weber, Lagergren, and Pseudo-Second-Order model (PSOM), were applied to represent the experimental results for both pyrolyzed and ZnCl2-oil shale sorbents. 相似文献
3.
In this paper, the improved version of the meshless singular boundary method(ISBM) is developed for analyzing the hydrodynamic performance of bottom-standing submerged breakwaters in regular normally incident waves. Both the single and dual prismatic breakwaters of rectangular and trapezoidal forms are examined. Only the impermeable breakwaters are considered in this study. The physical problem is cast in terms of the Laplace equation governing an irrotational flow and incompressible fluid motion with the appropriate mixed-type boundary conditions, and it is solved numerically using the ISBM. The numerical results are presented in terms of the hydrodynamic quantities of reflection and transmission coefficients. The values are first validated against the data of previous studies, computed, and discussed for a variety of structural conditions, including the height, width, and spacing of breakwater submergence. An excellent agreement is observed between the ISBM results and those of other methods. The breakwater width is found to feature marginal effects compared with the height. The present method is shown to accurately predict the resonant conditions at which the maximum reflection and transmission occur. The trapezoidal breakwaters are found to generally present a wide spectrum of reflections, suggesting that they would function better than the rectangular breakwaters. The dual breakwater systems are confirmed to perform much better than single structures. 相似文献
4.
Bouras Fawzi Al-Mukhtar Muzahim Tapsoba Nouffou Belayachi Naima Sabio Serge Beck Kévin Martin Mylène 《Geotechnical and Geological Engineering》2022,40(4):2033-2049
Geotechnical and Geological Engineering - An investigation performed on the interactions of silty soil treated with cement or lime demonstrates the strong relationship between microstructural... 相似文献
5.
The impact of the wastewater input of Médiouna agglomeration (southeastern area of Casablanca) on the diatom flora and water quality of Oued Hassar stream (Morocco) was studied from July 1997 to August 1998. This wastewater effluent, which was highly loaded with ammonia, orthophosphates and organic matters, had disturbed the diatom assemblages structure and water quality of this stream.The study of the epilithic algal assemblages revealed the presence of 130 taxa of diatoms, 21 of which, according to the available literature, were recorded for the first time in the Moroccan inland waters. Almost all the latter taxa are mesohalobic or oligohalobic-indifferent. Nitzschia inconspicua Grun. was the most abundant species (47.7%) and grows particularly at the source of the stream. Navicula subminuscula Manguin, Nitzschia capitellata Hust. and Nitzschia desertorum Hust. have their dominance in the highly polluted zones, especially downstream the wastewater input. 相似文献
6.
The present work deals with meandering and bank erosion of the River Nile of Egypt and its environmental impact between Sohag and El-Minia, Egypt. The study depends on using Landsat imagery acquired on 1987–2000 and field observations. Field observations, remote sensing, and GIS analysis and sinuosity index were used in this study to investigate river meandering and the associated processes of erosion of river bank and islands, deposition of sediments and formation of new islands. The analysis of Landsat imagery revealed the migration of river course with time and space. Some islands disappear completely in the study area whereas new islands appear in other places. The lateral erosion on the river banks led to a decrease in agricultural lands bordering the river banks and decrease in the areas of the river islands which in turn reduces the agricultural production. Depositional processes create new floodplains on the convex sides of the river course and new islands and sand bars. Protection methods are recommended to protect the river bank from further movement and erosion. The present conditions of river meandering and the associated processes of erosion and deposition accelerated with human activities have its impact on the environment. The most prominent hazard problem is reduction of agricultural lands and loss of property as well as navigation problems. River control is recommended to weaken the secondary currents created by the river bends. It is recommended to regularly monitor the river banks and islands and measure the rates of erosion and deposition. Sand bars and subsurface islands should be monitored and identified with flash lights to mitigate navigation problems. 相似文献
7.
Physical and chemical activation of pyrolyzed oil shale residue for the adsorption of phenol from aqueous solutions 总被引：4，自引：0，他引：4
Batch kinetics and isotherm studies were carried out to evaluate the sorption of phenol by pyrolyzed and activated Jordanian oil-shale. The effects of contact time, initial sorbate concentration, sorbent concentration, temperature, pH and inorganic salts (NaCl and KCl), on the adsorption process by different sorbents were considered. Chemically activated oil shale, pretreated with ZnCl 2, gave the highest uptake of phenol. The isotherm experimental data fit well to Freundlich and Redlich-Paterson models and to a less extent to the Langmuir model. The increase in the initial sorbate concentration resulted in an increase in the uptake. Three kinetics models, namely the Morris-Weber model, the Lagergren model, and the pseudo-second-order model (PSOM), were applied to represent the experimental results for pyrolyzed and ZnCl 2-oil shale sorbents. Pyrolyzed oil shale was prepared using a fluidized bed reactor at 520 °C in the presence of nitrogen. Physical activation was carried out by treating the resulted pyrolyzed oil shale with CO 2 at 830 °C, while chemical activation of oil shale was carried out using KOH and ZnCl 2 as impregnating agents. 相似文献
8.
Adsorption of copper and zinc by oil shale 总被引：8，自引：0，他引：8
Oil shale is able to remove appreciable amounts of copper and zinc ions from aqueous solutions. It was noted that an increase
in the adsorbent concentration with constant copper or zinc concentration resulted in greater metal removal from solution.
An increase in the copper or zinc concentration with a constant sorbent concentration resulted in higher metal loading per
unit weight of sorbent. For both metals, copper and zinc, equilibrium was attained after 24-h contact time. Increase in the
initial pH or temperature of the metal solution resulted in an increase in the metal uptake per unit weight of the sorbent.
Freundlich isotherm model was found to be applicable for the experimental data of Cu2+ and Zn2+. The results showed that oil shale could be used for the adsorption of the Cu2+ and Zn2+ with higher affinity toward Zn2+ ions. Addition of sodium salt to the metal solution influenced copper removal positively, but inhibited zinc removal.
Received: 3 January 2000 · Accepted: 27 June 2000 相似文献
9.
Fawzi Asadi Dr. 《GeoJournal》1990,21(4):375-383
A key objective of the Israeli occupation of the West Bank and Gaza Strip in Palestine has been to render the economy of these regions dependent on the Israeli economy and thus hamper their economic development. Large areas of land have been confiscated or expropriated by the Israeli authorities to establish Jewish settlements. Other severe measures imposed include control of irrigation water and obstacles for the Arab agricultural and industrial sector in the Occupied Territories aimed at preventing Arab competition with Israeli products.Palestinian agriculturalists have met this challenge and have worked to achieve higher production levels in agriculture. Nonetheless, economic development there was blocked, and many agriculturalists sought employment inside Israel. The Intifada since December 1987 has aimed at encouraging Arab economic independence and intensification of efforts to meet national requirements of greater self-sufficiency in subsistence crops and stimulation of agriculture-related industries. The Intifada is thus functioning as a stimulus to development and economic viability. 相似文献
10.
Imene Meriem Benbakhti Said Maouche Djelloul Belhai Assia Harbi Jean-François Ritz Ghilles Rabai Ahmed Rezouk Fawzi Doumaz 《Journal of Seismology》2018,22(6):1549-1561
In this work, we reappraise the seismogenic potential of the geologic structures in the western Tell Atlas of Algeria, considered active host to moderate to low magnitude earthquakes. The direct identification of active faults is generally a difficult task in northern Algeria. The active tectonics in the Oran Plio-Quaternary age basin (Northwestern Algeria) is analyzed and characterized through a morpho-structural study combining topographic, geomorphologic, geological, and neotectonic data. Folds and fault scarps affecting Quaternary deposits show that the region is affected by compressional deformation still active nowadays, as shown by the recorded seismic activity. Our new observations enable a better understanding of the present seismotectonic context of the Oran region, particularly with regard to the magnitude and source of the 1790 Oran damaging event. The obtained result helps to shed some light on the elusive active tectonics characterizing this coastal area, and to assess regional seismic hazard, particularly in coastal zones where large seismogenic areas straddle the onshore–offshore zones. 相似文献