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Central European Journal of Engineering最新文献

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The variational iteration method for solving linear and nonlinear ODEs and scientific models with variable coefficients 求解线性、非线性ode和变系数科学模型的变分迭代法
Central European Journal of Engineering Pub Date : 2014-05-29 DOI: 10.2478/s13531-013-0141-6
A. Wazwaz
{"title":"The variational iteration method for solving linear and nonlinear ODEs and scientific models with variable coefficients","authors":"A. Wazwaz","doi":"10.2478/s13531-013-0141-6","DOIUrl":"https://doi.org/10.2478/s13531-013-0141-6","url":null,"abstract":"We apply the variational iteration method (VIM) for solving linear and nonlinear ordinary differential equations with variable coefficients. We use distinct Lagrange multiplier for each order of ODE. We emphasize the power of the method by testing a variety of models with distinct orders and variable coefficients. Scientific models, namely, the hybrid selection model, the Thomas-Fermi equation, the Kidder equation of the Unsteady flow of gas through a porous medium, and the Riccati equation, are studied as well.","PeriodicalId":407983,"journal":{"name":"Central European Journal of Engineering","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116642819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 57
Valorization of agricultural waste into activated carbons and its adsorption characteristics for heavy metals 农业废弃物活化成活性炭及其对重金属的吸附特性研究
Central European Journal of Engineering Pub Date : 2014-05-29 DOI: 10.2478/s13531-013-0148-z
B. Koubaissy, J. Toufaily, S. Cheikh, M. Hassan, T. Hamieh
{"title":"Valorization of agricultural waste into activated carbons and its adsorption characteristics for heavy metals","authors":"B. Koubaissy, J. Toufaily, S. Cheikh, M. Hassan, T. Hamieh","doi":"10.2478/s13531-013-0148-z","DOIUrl":"https://doi.org/10.2478/s13531-013-0148-z","url":null,"abstract":"Activated carbon derived from pine cones waste was prepared by carbonization at 450°C, activated by different activating agents: ZnCl2, H2SO4 and NaOH, and then pyrolyzed at 600°C. Adsorption of Cr VI and other heavy metals (Mn II, Fe II, Cu II) on activated carbons was investigated to evaluate the adsorption properties. Special attention was paid to the effects of carbon surface functionalities that were analyzed by FT-IR and zeta potential study. Moreover, XRD study of activated carbon was also carried out. Results had shown that activated carbon by NaOH was the best adsorbent for removal of chromium VI from wastewater. The solid-solution interaction was determined by analyzing the adsorption isotherms at room temperature at different pH. When pH is above 4, the removal fraction of Cr (VI) ions decreased with the increase of pH. The removal fraction of Cr (VI) ions decreased below pH 4. The preferable removal of Cu (II) over Mn(II) and Fe (II) could be due to its lower affinity to solvent.Pseudo-second order equation provided the better correlation for the adsorption kinetics data. Equilibrium isotherms were determined by Fowler-Guggenheim model.","PeriodicalId":407983,"journal":{"name":"Central European Journal of Engineering","volume":"61 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116693082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 12
Stacked configuration of rectangular and hexagonal patches with shorting pin for circularly polarized wideband performance 带短引脚的矩形和六角形贴片的堆叠结构对圆极化宽带性能的影响
Central European Journal of Engineering Pub Date : 2014-05-29 DOI: 10.2478/s13531-013-0136-3
S. Rawat, K. Sharma
{"title":"Stacked configuration of rectangular and hexagonal patches with shorting pin for circularly polarized wideband performance","authors":"S. Rawat, K. Sharma","doi":"10.2478/s13531-013-0136-3","DOIUrl":"https://doi.org/10.2478/s13531-013-0136-3","url":null,"abstract":"The radiation characteristics of a stacked microstrip antenna geometry proficient of providing circular polarization along with wide impedance bandwidth is simulated by using IE3D software and later on this antenna was fabricated on FR-4 substrate with an air gap and testing is done in free space. The feed location, location of applied shorting pin and width of air gap introduced between driver element and parasitically coupled element were optimized to obtain best results. The measured impedance bandwidth better than 31.72% and axial ratio bandwidth close to 1.68% were achieved with the proposed geometry. The simulated and measured results obtained are in good match with each other.","PeriodicalId":407983,"journal":{"name":"Central European Journal of Engineering","volume":"165 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123006900","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 21
On MHD unsteady reactive Couette flow with heat transfer and variable properties 换热变性质MHD非定常反应库埃特流研究
Central European Journal of Engineering Pub Date : 2014-05-29 DOI: 10.2478/s13531-013-0139-0
O. Makinde, Oswald Franks
{"title":"On MHD unsteady reactive Couette flow with heat transfer and variable properties","authors":"O. Makinde, Oswald Franks","doi":"10.2478/s13531-013-0139-0","DOIUrl":"https://doi.org/10.2478/s13531-013-0139-0","url":null,"abstract":"This study is devoted to investigate the effect of magnetic field on a reactive unsteady generalized Couette flow with temperature dependent viscosity and thermal conductivity. It is assumed that conducting incompressible fluid is subjected to an exothermic reaction under Arrhenius kinetics, neglecting the consumption of the material. The model nonlinear differential equations governing the transient momentum and energy balance are obtained and tackled numerically using a semi-discretization finite difference technique coupled with Runge-Kutta Fehlberg integration scheme. Important properties of the velocity and temperature fields including thermal stability conditions are presented graphically and discussed quantitatively.","PeriodicalId":407983,"journal":{"name":"Central European Journal of Engineering","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132069197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 15
Microwave plasma assisted pyrolysis of refuse derived fuels 微波等离子体辅助垃圾衍生燃料的热解
Central European Journal of Engineering Pub Date : 2014-05-29 DOI: 10.2478/s13531-013-0142-5
P. Khongkrapan, P. Thanompongchart, N. Tippayawong, T. Kiatsiriroat
{"title":"Microwave plasma assisted pyrolysis of refuse derived fuels","authors":"P. Khongkrapan, P. Thanompongchart, N. Tippayawong, T. Kiatsiriroat","doi":"10.2478/s13531-013-0142-5","DOIUrl":"https://doi.org/10.2478/s13531-013-0142-5","url":null,"abstract":"This work combined plasma reactivity and pyrolysis for conversion of solid wastes. Decomposition of refuse derived fuel (RDF) and its combustible components (paper, biomass, and plastic) in an 800 W microwave plasma reactor was investigated at varying argon flow rates of 0.50 to 1.25 lpm for 3 minutes. The characteristic bright light emission of plasma was observed with calculated maximum power density of about 35 W/cm3. The RDF and its components were successfully converted into char and combustible gas. The average char yield was found to be 12–21% of the original mass, with a gross calorific value of around 39 MJ/kg. The yield of the product gas was in the range 1.0–1.7 m3/kg. The combustible gas generated from the pyrolysis of the RDF contained about 14% H2, 66% CO, and 4% CH4 of the detected gas mass, with a heating value of 11 MJ/m3. These products are potentially marketable forms of clean energy.","PeriodicalId":407983,"journal":{"name":"Central European Journal of Engineering","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127514991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 16
Influence of malfunctions of the maintenance activities on the urban buses fuel consumption 维修活动故障对城市客车燃油消耗的影响
Central European Journal of Engineering Pub Date : 2014-05-19 DOI: 10.2478/s13531-013-0144-3
Crișan Horea George, Filip Nicolae
{"title":"Influence of malfunctions of the maintenance activities on the urban buses fuel consumption","authors":"Crișan Horea George, Filip Nicolae","doi":"10.2478/s13531-013-0144-3","DOIUrl":"https://doi.org/10.2478/s13531-013-0144-3","url":null,"abstract":"Optimization of activities with the aim to provide quality service in conditions of high profitability, is one of the main objectives chased by managers in transportation companies. As a consequence, directing the attention towards monitoring of maintenance activities of vehicles fleet, can achieve desired results. Two of the most important issues related to the maintenance activity, is the increase of reliability and reduction of fuel consumption of the vehicles fleet. Aforementioned actions represents a way forward for raising the quality and profitability of services offered. In this paper, the main ways of monitoring the fuel consumption, in order to reduce it and increase the reliability of transportation vehicles fleet, are presented. For the evaluation of the maintenance system and the degree of influence of malfunctions recorded on the fuel consumption, using the Pareto -ABC method, following case study on a fleet of buses for urban public transport has been conducted. Results obtained highlights the deficiencies of the maintenance process carried out and constitutes a solid base for the reorganization of the maintenance activity, involving preventive maintenance activities, in order to contribute decisively to the results targeted by the management of transport companies.","PeriodicalId":407983,"journal":{"name":"Central European Journal of Engineering","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126423036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 3
Prediction of liquefaction potential and pore water pressure beneath machine foundations 机器基础下液化势和孔隙水压力预测
Central European Journal of Engineering Pub Date : 2014-05-13 DOI: 10.2478/s13531-013-0165-y
M. Fattah, M. Al-Neami, N. Jajjawi
{"title":"Prediction of liquefaction potential and pore water pressure beneath machine foundations","authors":"M. Fattah, M. Al-Neami, N. Jajjawi","doi":"10.2478/s13531-013-0165-y","DOIUrl":"https://doi.org/10.2478/s13531-013-0165-y","url":null,"abstract":"The present research is concerned with predicting liquefaction potential and pore water pressure under the dynamic loading on fully saturated sandy soil using the finite element method by QUAKE/W computer program. As a case study, machine foundations on fully saturated sandy soil in different cases of soil densification (loose, medium and dense sand) are analyzed. Harmonic loading is used in a parametric study to investigate the effect of several parameters including: the amplitude frequency of the dynamic load. The equivalent linear elastic model is adopted to model the soil behaviour and eight node isoparametric elements are used to model the soil. Emphasis was made on zones at which liquefaction takes place, the pore water pressure and vertical displacements develop during liquefaction. The results showed that liquefaction and deformation develop fast with the increase of loading amplitude and frequency. Liquefaction zones increase with the increase of load frequency and amplitude. Tracing the propagation of liquefaction zones, one can notice that, liquefaction occurs first near the loading end and then develops faraway. The soil overburden pressure affects the soil liquefaction resistance at large depths. The liquefaction resistance and time for initial liquefaction increase with increasing depths. When the frequency changes from 5 to 10 rad/sec. (approximately from static to dynamic), the response in displacement and pore water pressure is very pronounced. This can be attributed to inertia effects. Further increase of frequency leads to smaller effect on displacement and pore water pressure. When the frequency is low; 5, 10 and 25 rad/sec., the oscillation of the displacement ends within the period of load application 60 sec., while when ω = 50 rad/sec., oscillation continues after this period.","PeriodicalId":407983,"journal":{"name":"Central European Journal of Engineering","volume":"96 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116053623","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 12
An estimation of critical buckling strain for pipe subjected plastic bending 塑性弯曲管道临界屈曲应变的估计
Central European Journal of Engineering Pub Date : 2014-05-13 DOI: 10.2478/s13531-013-0168-8
L. Ji, M. Zheng, H. Y. Chen, Y. Zhao, Lijun Yu, Jun Hu, H. Teng
{"title":"An estimation of critical buckling strain for pipe subjected plastic bending","authors":"L. Ji, M. Zheng, H. Y. Chen, Y. Zhao, Lijun Yu, Jun Hu, H. Teng","doi":"10.2478/s13531-013-0168-8","DOIUrl":"https://doi.org/10.2478/s13531-013-0168-8","url":null,"abstract":"An approach for estimating critical buckling strain of pipe subjected plastic bending is established in the present paper. A rigid — perfectly plastic material model and cross section ovalization of pipe during bending are employed for the approach. The energy rates of the ovalised pipe bending and the cross section ovalising are proposed firstly. Furthermore, these energy rates are combined to perform the buckling analysis of pipe bending, an estimation formula of critical buckling strain for pipe subjected plastic bending is proposed. The predicting result of the new critical buckling strain formula is compared with the available experimental data, it shows that the formula is valid.","PeriodicalId":407983,"journal":{"name":"Central European Journal of Engineering","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128740401","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
A new monitoring technique for the grounding grids 一种新的接地网监测技术
Central European Journal of Engineering Pub Date : 2014-05-06 DOI: 10.2478/s13531-013-0164-z
Y. Chikarov, T. Lie, N. Nair
{"title":"A new monitoring technique for the grounding grids","authors":"Y. Chikarov, T. Lie, N. Nair","doi":"10.2478/s13531-013-0164-z","DOIUrl":"https://doi.org/10.2478/s13531-013-0164-z","url":null,"abstract":"The performance and reliability of grounding grids depend on its structural integrity. If grounding conductors are damaged, it may cause misoperation of protective relay which leads to trip feeders unnecessarily. It can also cause not only failures on the surroundings such as the grounding grid, secondary circuits’ cables, and structural elements but also voltage hazard for human. The circuits may attain unacceptable voltages when short-circuit fault currents occur in these grids. This paper presents the development of a new technique to monitor the operating conditions of the grounding grids of high voltage apparatus and systems without any diggings and forced outages. New concept, principals, a technique and a device shown in the paper have never been described before by the other authors. The technique is based on the evaluation of the electromagnetic field distribution pattern over the damaged horizontal elements of the grid.","PeriodicalId":407983,"journal":{"name":"Central European Journal of Engineering","volume":"695 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116115944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 3
A compact broadband microstrip patch antenna with defective ground structure for C-Band applications c波段应用中具有缺陷接地结构的紧凑宽带微带贴片天线
Central European Journal of Engineering Pub Date : 2014-04-29 DOI: 10.2478/s13531-013-0162-1
S. Rawat, K. Sharma
{"title":"A compact broadband microstrip patch antenna with defective ground structure for C-Band applications","authors":"S. Rawat, K. Sharma","doi":"10.2478/s13531-013-0162-1","DOIUrl":"https://doi.org/10.2478/s13531-013-0162-1","url":null,"abstract":"A novel design of a circular patch antenna having defected ground structure is presented in this communication. The antenna is designed for C-band applications. A wide bandwidth of 60.3% (4.04–7.28) GHz is obtained in the C-band frequency range 4–8 GHz. It is also found through parametric analysis that shape and dimensions of the finite ground plane and slots in the patch are the key factors in improving the bandwidth of the proposed geometry. The antenna is fabricated using FR-4 substrate and parameters like return loss, VSWR and input impedance are measured experimentally.","PeriodicalId":407983,"journal":{"name":"Central European Journal of Engineering","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128447311","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 47
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