检索结果-南通市图书馆

Effect of postweld heat treatment on interface microstructure and metallurgical properties of explosively welded bronze–carbon steel

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2018年第8期25卷 1849-1861页

作者： KHANZADEH GHARAHSHIRAN Mohammad reza KHOSHAKHLAGH Ali KHALAJ Gholamreza BAKHTIARI Hamid BANIHASHEMI Ali reza Center for Advanced Engineering Research Majlesi Branch Islamic Azad University Young Researchers and Elites Club Science and Research Branch Islamic Azad University Young Researchers and Elites Club Saveh Branch Islamic Azad University Department of Materials Engineering Najafabad Branch Islamic Azad University Department of Materials Engineering Shahreza Branch Islamic Azad University

The effects of postweld heat treatment on the microstructure and metallurgical properties of a bronze–carbon steel(st37)explosively bonded interface were *** welding was done under 1.5-and 2-mm standoff distances and different conditions of explosive *** were postweld heat treated for 4 and 16 h in the furnace at 250°C and 500°C and then air *** studies using optical microscopy,scanning electron microscopy,and microhardness testing were used to evaluate the welded *** examinations showed that by increasing the standoff distance and the explosive charge,the interface of bronze to steel became *** microhardness test result showed that the hardness of the samples was higher near the joint interface compared with other areas because of the intensive plastic deformation,which was caused by the explosion *** results show that increasing the heat treatment temperature and time caused the intermetallic compounds’layer thickness to increase,and,because of the higher diffusion of copper and tin,the iron amount in the intermetallic compounds ***,because of the increase in heat treatment temperature and time,internal stresses were released,and the interface hardness decreased.

关键词： heat treatment explosive welding intermetallic compound standoff distance diffusion layer

Numerical and experimental study of an innovative pipeline design in a granular pneumatic-conveying system

在线全文

学校读者我要写书评

暂无评论

Particuology 2018年第3期16卷 196-203页

作者： Hasan Ghafori Hamid reza Ebrahimi Department of Mechanical Engineering MaJlesi Branch Islamic Azad University lsfilhan Iran Department of Chemical Engineering Majlesi Branch Islamic Azad University lsfahan Iran

During gas-solid mixture conveying in a dense phase, material is conveyed in dunes on the bottom of the pipeline, or as a pulsating moving bed. This phenomenon increases the pressure drop and power consumption. We introduce a new technique to reduce the pressure drop, which is termed the perforated double tube. To validate this new model, the gas-solid flow pattern and pressure drop were studied numerically and experimentally. The power consumption was also studied experimentally. Numerical studies were performed by the Eulerian-Lagrangian approach to predict gas and particle movement in the pipeline, Comparisons between the numerical predictions and the experimental results for the gas-solid flow patterns and pressure drop show good agreement.

关键词： Computational fluid dynamics Power consumption Perforated double tube Pneumatic conveying

3D numerical parametric study of the influence of open-pit mining sequence on existing tunnels

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Mining Science and Technology 2017年第3期27卷 459-466页

作者： Beyabanaki Amir reza Gall Vojtech McMillen Jacobs Associates San Francisco CA 94105 USA Gall Zeidler Consultants Ashburn VA 20147 USA

The development of open-pit mines can adversely affect and even damage existing access tunnels. To ensure the safety and serviceability of them, it is essential to know potential adverse effects of the mining sequence on existing tunnels such as displacements of the lining and additional loads on the lining. In this paper, three-dimensional numerical parametric study is performed to explore this complex interaction. This study investigates the effects of different parameters that may affect the tunnel response. These parameters are： excavation sequence method, horizontal/vertical stress ratio, slope angle, and tunnel diameter. This study shows that the mining sequence affects the stability of the tunnels. The open-pit mining activities lead to both higher axial forces in rock bolts and normal forces and bending moments in the lining. The results of the analysis also demonstrate that the mining sequence causes tunnel heave and significant tensile forces in the lining. Based on the study in this paper a better understanding of the interaction between oDen-oit minin~ seouence and tunnels will he ohtained

关键词： Three-dimensionalNumerical parametric studyExisting tunnelOpen-pit mining sequenceModeling

Modeling of unconfined compressive strength of soil-RAP blend stabilized with Portland cement using multivariate adaptive regression spline

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2019年第4期13卷 787-799页

作者： Ali reza GHANIZADEH Morteza RAHROVAN Department of Civil Engineering Sirjan University of Technology Sirjan 78137-33385 Iran Department of Civil Engineering Yazd University Yazd 89195-741 Iran

The recycled layer in full-depth reclamation (FDR) method is a mixture of coarse aggregates and reclaimed asphalt pavement (RAP) which is stabilized by a stabilizer agent. For design and quality control of the final product in FDR method, the unconfined compressive strength of stabilized material should be known. This paper aims to develop a mathematical model for predicting the unconfined compressive strength (UCS) of soil-RAP blend stabilized with Portland cement based on multivariate adaptive regression spline (MARS). To this end, two different aggregate materials were mixed with different percentages of RAP and then stabilized by different percentages of Portland cement. For training and testing of MARS model, total of 64 experimental UCS data were employed. Predictors or independent variables in the developed model are percentage of RAP, percentage of cement, optimum moisture content, percent passing of #200 sieve, and curing time. The results demonstrate that MARS has a great ability for prediction of the UCS in case of soil-RAP blend stabilized with Portland cement (R2 is more than 0.97). Sensitivity analysis of the proposed model showed that the cement, optimum moisture content, and percent passing of #200 sieve are the most influential parameters on the UCS of FDR layer.

关键词： full-depth reclamation soil-reclaimed asphalt pavement blend Portland cement unconfined compressive strength multivariate adaptive regression spline

Finite element model updating of a large structure using multi-setup stochastic subspace identification method and bees optimization algorithm

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2019年第4期13卷 965-980页

作者： reza KHADEMI-ZAHEDI Pouyan ALIMOURI Institute of Structural Mechanics Bauhaus-Universitat WeimarWeimar 99423Germany Mechanical Engineering Department Shahid Chamran University of AhvazAhvazIran

In the present contribution, operational modal analysis in conjunction with bees optimization algorithm are utilized to update the finite element model of a solar power plant structure. The physical parameters which required to be updated are uncertain parameters including geometry, material properties and boundary conditions of the aforementioned structure. To determine these uncertain parameters, local and global sensitivity analyses are performed to increase the solution accuracy. An objective function is determined using the sum of the squared errors between the natural frequencies calculated by finite element method and operational modal analysis, which is optimized using bees optimization algorithm. The natural frequencies of the solar power plant structure are estimated by multi-setup stochastic subspace identification method which is considered as a strong and efficient method in operational modal analysis. The proposed algorithm is efficiently implemented on the solar power plant structure located in Shahid Chamran university of Ahvaz, Iran, to update parameters of its finite element model. Moreover, computed natural frequencies by numerical method are compared with those of the operational modal analysis. The results indicate that, bees optimization algorithm leads accurate results with fast convergence.

关键词： operational modal analysis solar power plant structure multi-setup stochastic subspace bees optimization algorithm sensitivity analysis

A New Method for Clustering Based on Development of Imperialist Competitive Algorithm

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China Communications 2014年第12期11卷 54-61页

作者： Mohammad reza Dehghani Zadeh Mohammad Fathian Mohammad reza Gholamian School of Industrial Engineering Iran University of Science and Technology Narmak 16844 Tehran Iran

Clustering is one of the most widely used data mining techniques that can be used to create homogeneous clusters.K-means is one of the popular clustering algorithms that,despite its inherent simplicity,has also some major *** way to resolve these problems and improve the k-means algorithm is the use of evolutionary algorithms in *** this study,the Imperialist Competitive Algorithm(ICA) is developed and then used in the clustering *** of IRIS,Wine and CMC datasets using developed ICA and comparing them with the results of clustering by the original ICA,GA and PSO algorithms,demonstrate the improvement of Imperialist competitive algorithm.

关键词： data mining homogeneous cluster imperialist competitive algorithm

Stabilizing silica nanoparticles in high saline water by using polyvinylpyrrolidone for reduction of asphaltene precipitation damage under dynamic condition

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2019年第5期27卷 1021-1029页

作者： Mohammad reza Aghajanzadeh Mohammad Sharifi Department of Petroleum Engineering Amirkabir University of Technology

In this study, the performance of stable nanofluid containing SiO2 nanoparticles dispersed and stabilized in high salinity brine for asphaltene inhibition in dynamic condition is evaluated. In the first stage of this work, the stability of silica nanoparticles in different range of water salinity(0–100000 mg·L-1) is investigated. Next, stable nanofluid containing highest salinity is selected as asphaltene inhibitor agent to inject into the damaged core sample. The estimated values of oil recovery for base case, after damage process and after inhibition of asphaltene precipitation using nanofluid are 51.6%, 36.1% and 46.7%, respectively. The results showed the reduction in core damage after using nanofluid. In addition, the relative permeability curves are plotted for the base case, after damage process and also after inhibition of asphaltene precipitation using nanofluid. Comparison of relative permeability curves shows, relative permeability of oil phase decreased after damage process as compared with the base case. But after using nanofluid the oil relative permeability curve has shifted to the right and effective permeability of oil phase has been improved.

关键词： Formation damage Enhanced oil recovery Salinity Asphaltene Core flooding Nano particles

Electrophoretic deposition and an investigation of co-dopants effect on luminescence property of Mg2SiO4:Eu3+phosphors

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2017年第12期35卷 1171-1179页

作者： Mehdi Ghahari Ali reza Naeimi Department of Nanomaterials and Nano Coatings Institute for Color Science and TechnologyTehranIran

Forsterite particles doped with europium ions（Eu^（3＋）） were synthesized via a solution combustion method. The effect of co-dopants on photoluminescence intensity was described. Different percentages of calcium（Ca^（2＋））, zinc（Zn^（2＋））, barium（Ba^（2＋）） and strontium（Sr^（2＋）） were added to the Mg2SiO4：Eu^（3＋）*** synthesized sample was characterized by X-ray diffraction, transmission electron microscopy,scanning electron microscopy, spectrofluorometer and the FTIR spectroscopy. X-ray diffraction（XRD）results revealed that dominant phase was forsterite in all samples. Additionally, a negligible amount of periclase phase was recognized in the samples. The average size of the synthesized particles was less than 200 nm. The presence of co-dopant led to an enhancement in the photoluminescent property of the synthesized samples. The maximum increase in photoluminescence intensity was obtained by Ba^（2＋）ions as a co-dopant. Condensed films of photoluminescence particles were produced by utilizing electrophoresis technique to deposit particles. The results showed that polyvinyl pyrrolidone was the best surface modifier to raise the mass deposition of the samples on the substrate.

关键词： Luminescence materials Forsterite Combustion syntheses Electrophoretic deposition

Evaluation of heavy metal contamination hazards in nuisance dust particles, in Kurdistan Province, western Iran

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2013年第7期25卷 1346-1354页

作者： reza Bashiri Khuzestani Bubak Souri Department of Environmental Sciences Faculty of Natural Resources University of Kurdistan

The effects of natural andgeochemical factors depending on heavy metal contamination in nuisance dust particles were evaluated. The nuisance dust particles were sampled using passive deposit gauge method for one year from April2010 to March2011 and the obtained samples were measured for the total contents and the contamination levels of Fe, Mn, Cu and As usinggeo-accumulation index （Igeo ）, enrichment factor （EF） and the integrated pollution index （IPI）. The results showed that, the contamination levels of Fe and Mn based on Igeo values, were uncontaminated （Igeo 〈 0）（variations of the Igeo index was from -3.11 to -1.751 for Fe, from -0.630 to -1.925 for Mn）, while the values of Cu and As were demonstrated to have moderate contamination based on Igeo values （variations of Igeo index was from -1.125 to 0.848 for Cu, and from -2.002 to 1.249 for As）. The analysis of EF also revealed minor to moderate enrichment for Mn （1.215-4.214）, minor to moderately severe enrichment for Cu （2.791-6.484）, and As （1.370-8.462）, respectively. The variation of the IPI index also showed low to moderate level of heavy metal pollution in nuisance dust particulates （0.511-1.829）. The analysis of the results also approved that the natural processes andgeochemical variables （the changing meteorological parameters） can significantly affect the availability of heavy metals in nuisance dust particles in Western Iran.

关键词： heavy metal contamination nuisance dust deposit gauge method geo-accumulation index enrichment factor integrated pollution index