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肝肿瘤:感兴趣区与容积分析在CT衰减值定量分析中的比较

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国际医学放射学杂志 2012年第3期 270-271页

作者： H.Chalian S.M.Tochetto H.G.Tre p.rezai V.Yaghmai 张红 Department of Radiology Northwestern University Feinberg School of Medicine676 N Saint Clair StSuite 800ChicagoIL 60611

目的 CT评估应用于常规的手工绘制感兴趣区(ROI)法和半自动容积分析方法对肝脏肿瘤密度衰减值测量的可重复性。材料与方法该项回顾性研究符合HIpAA并得到机构审查委员会的批准,免除病人知情同意。在多层螺旋CT门静脉期相上,采用单一ROI... 详细信息

目的 CT评估应用于常规的手工绘制感兴趣区(ROI)法和半自动容积分析方法对肝脏肿瘤密度衰减值测量的可重复性。材料与方法该项回顾性研究符合HIpAA并得到机构审查委员会的批准,免除病人知情同意。在多层螺旋CT门静脉期相上,采用单一ROI、同一层面3个ROI的平均值,以及半自动勾划整个肿瘤容积(容积的密度衰减值)的方

关键词：容积密度衰减值可重复性再现性结肠癌肝转移消化系肿瘤肝脏肿瘤感兴趣区 CT

Scleractinian coral communities of Hormuz Island in the persianGulf

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Acta Oceanologica Sinica 2022年第12期41卷 48-57页

作者： Yamin pouryousef Jafar Seyfabadi Hamid rezai Alireza Mahvari Mohammad Ali Jafari Department of Marine Biology Faculty of Marine SciencesTarbiat Modares UniversityNoor 46417Iran Darya Negar pars Consulting Engineers Tehran 14669Iran Department of Environment Hormozgan provincial Directorate Bandar Abbas 79168Iran

The abundance and health of scleractinian coral communities of Hormuz Island were investigated.For this purpose,we employed 20 m line intercept transects—12 in the intertidal zone and 15 subtidally to evaluate coral cover and community composition.The estimated dead coral coverage was 6.21%±0.81%,while live coral coverage was 16.93%±1.81%,considered as very poor.Totally,12 genera were recorded,of which porites with 11.9%±1.4%live cover was the dominant,while Goniopora had the least cover(0.07%±0.08%).Based on Mann-Whitney U-test,live coral coverage,dead coral coverage,algal coverage,cover of other benthic organisms and abiotic components showed significant univariate differences between zones(ppearman correlation test between the abundance of biotic and abiotic components indicated significant negative correlation of live coral and sand with zoantharian and significant positive correlation of algae and other benthic organisms with rubble.The reef health indices used for the corals indicated that,in general,the environmental conditions were not suitable,which could be attributed to both natural and anthropogenic factors,the most important of which was zoantharian’overgrowth on the scleractinian corals in this region.

关键词： scleractinian corals zoantharian reef health indices Hormuz Island persian Gulf

Effects of dieback on the vegetative, chemical, and physiological status of mangrove forests, Iran

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Journal of Arid Land 2023年第11期15卷 1391-1404页

作者： Vahid Farashi KAHNOUJ Marzieh rezai Rasool MAHDAVI Maryam MOSLEHI Saiedeh ESKANDARI Natural Resources Engineering Group Desert Management and ControlUniversity of HormozganHormozganBandarabass ***Iran Natural Resources Engineering Group Faculty of Agriculture and Natural ResourcesUniversity of HormozganHormozganBandarabass ***Iran Research Division of Natural Resources Hormozgan Agricultural and Natural Resources Research and Education CenterAgricultural ResearchEducation and Extension Organization(AREEO)Bandarabbas ***Iran Forest Research Division Research Institute of Forests and RangelandsAgricultural ResearchEducation and Extension Organization(AREEO)Tehran ***Iran

Mangrove forests are valuable resources in tropical and subtropical regions,which have been faced dieback due to various human activities including rapid expansion of shrimp farming,urban development,and pollution,as well as natural factors such as rising sea level,increasing air temperature,drought,and sharp decrease in rainfall.However,the mechanisms of dieback of mangrove forests are not well understood.Therefore,this research aimed to assess the vegetative,chemical,and physiological status of grey mangrove(Avicennia marina(Forsk.)Vierh.)forests at different intensities of dieback in the Hormozgan province,Iran.A total of 40 plots categorized into four dieback intensities(severe,medium,low,and control)were randomly selected for monitoring,and various parameters related to vegetative,chemical,and physiological status of grey mangrove forests were examined.The results revealed that the control group had the highest tree density,seedling density,vitality levels,aerial root density,and aerial root height.Generally,as dieback severity increased,a decrease in demographic and vegetative parameters of trees and seedlings was observed in the dieback treatments.The amounts of heavy metals(lead,cadmium,and nickel)in the sediment,roots,and leaves of grey mangrove trees at different dieback levels indicated that lead levels were the highest in the sediment,roots,and leaves in the severe dieback treatment.At the same time,the control had the lowest values.Cadmium concentrations in the sediment followed the pattern of severe dieback>moderate dieback>low dieback>control with no significant differences in the roots and leaves.Nickel amounts in all three parts,i.e.,sediment,roots,and leaves showed the highest levels in the severe dieback treatment.Furthermore,metal level analysis in the organs of grey mangrove trees at different dieback levels revealed that lead and nickel were more abundant in the root organ compared with the leaves.In contrast,the leaf organ exhibited the highest cadmium levels.Dieback significantly impacted

关键词： nickel forests grey

parametric study of droplet size in an axisymmetric flow-focusing capillary device

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Chinese Journal of Chemical Engineering 2020年第4期28卷 1016-1022页

作者： Mostafa Rahimi Sajad Yazdanparast pouya rezai Department of Mechanical Engineering University of Mohaghegh ArdabiliArdabilIran Department of Mechanical Engineering York UniversityTorontoONCanada

A conventional technique for microfluidic droplet generation is Co-axial Flow Focusing(CFF)in which a contraction zone is placed downstream of the dispersed phase nozzle.In this contraction zone,the dispersed-phase(dphase)fluid is pinched off by continuous-phase(c-phase)fluid to generate micro-droplets.Studying the influence of multiple parameters such as the fluids velocities and viscosities,the interfacial tension,and nozzle and orifice diameters on the droplet size is of great importance for the design and application of CFF devices.Thus,development of more complete numerical models is required.In this paper,we show our model is compatible with experimental data and then numerically investigate the effects of aforementioned parameters on the droplet generation in a CFF microfluidic device.Simulation results showed that the c-phase flow rate,viscosity and the interfacial tension had great impacts on the droplet size.The effect of the nozzle diameter on the generated droplet size was small compared to that of the orifice in a CFF device.Using the simulation results,a correlation was also developed and suggested which predicts the droplet size with less than 15%error in a wide range of the introduced dimensionless parameters.

关键词： Co-axial Flow Focusing Microfluidics Droplet generation Numerical investigation

Estimation of froth flotation recovery and collision probability based on operational parameters using an artificial neural network

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International Journal of Minerals,Metallurgy and Materials 2010年第5期17卷 526-534页

作者： Saeed Chehreh Chelgani Behzad Shahbazi Bahram rezai Surface Science Western Research Park University of Western Ontario Mining Engineering Department Science and Research Branch Islamic Azad University Amirkabir University of Technology

An artificial neural network and regression procedures were used to predict the recovery and collision probability of quartz flotation concentrate in different operational conditions. Flotation parameters, such as dimensionless numbers （Froude, Reynolds, and Weber）, particle size, air flow rate, bubble diameter, and bubble rise velocity, were used as inputs to both methods. The linear regression method shows that the relationships between flotation parameters and the recovery and collision probability of flotation can achieve correlation coefficients （R2） of 0.54 and 0.87, respectively. A feed-forward artificial neural network with 3-3-3-2 arrangement is able to simultaneously estimate the recovery and collision probability as the outputs. In testing stages, the quite satisfactory correlation coefficient of 0.98 was achieved for both outputs. It shows that the proposed neural network models can be used to determine the most advantageous operational conditions for the expected recovery and collision probability in the froth flotation process.

关键词： flotation recovery collision probability neural networks

Selective separation of gallium from aluminum in SDS–Ga–Al and SDS–Ga–Al–fluoride systems by ion flotation

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Journal of Central South University 2017年第4期24卷 789-795页

作者： Bahri Zahra rezai Bahram1 Kowsari Elaheh Department of Mining and Metallurgical Engineering Amirkabir University of TechnologyTehran 158754413Iran Department of Chemistry Amirkabir University of TechnologyTehran 15916-34311Iran

Selective separation of gallium from aluminum by ion flotation using sodium dodecyl sulfate(SDS) as an anionic surfactant and fluoride as an inorganic ligand was investigated. The experimental results were analyzed using the stability constants and speciation diagrams of fluoride metal complexes. The presence of fluoride in the solution has a positive influence upon the separation of gallium from aluminum. The results show that increasing the fluoride concentration makes a more effective separation of gallium from aluminum because of a simultaneous increase in the complexion of aluminum with fluoride and a change in the electrical charge of the aluminum(ALF_4^-). The dehydration model of LIU and DOYLE was also applied to compare the ion flotation and the selectivity coefficients of gallium over aluminum with experimental results.

关键词： ion flotation gallium(Ⅲ) selective separation inorganic ligand

Dynamic simulation of the effect of time-dependent variation of pH on response variable of the tailing thickener of coal washing plant

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International Journal of Coal Science & Technology 2019年第1期6卷 127-137页

作者： Mehdi Rahimi Ali Akbar Abdollahzadeh Bahram rezai Department of Mining and Metallurgical Engineering Amirkabir University of Technology TehranIran Department of Mining Engineering University of KashanKashanIran

Dynamic simulation approach can be used for understanding the nonlinear behavior in mineral processing circuits. In this study, the gel point, the main parameters of batch flux density function and the main parameters of effective solid stress were determined at different conditions (pH, flocculant dosage and particle size). Therefore, the main parameters of phenome no logical model of sedimentation and thickening were determined as a functio n of particle size, pH and flocculant dosages using the result of experimental tests and Curve expert professional software. Then, the dynamic simulation was carried out for the industrial thickener of coal washing plant and the time-dependent variation of response variables was investigated by time-dependent variation of pH of input feed to thickener using the obtained equations. It was observed that it is possible to predict the thickener behavior as a function of time for time dependent variation of pH of input feed to the thickener of coal washing plant using obtained equations that it was not possible using phenomenological model of thickener alone.

关键词： Dynamic simulation Dewatering Ideal continuous thickener Thickener behavior Time-dependent variation of pH

Dynamic simulation of pilot thickener operation using phenomenological model with results validation for continuous and discontinuous tests

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Journal of Central South University 2017年第5期24卷 1207-1216页

作者： Rahimi Mehdi Unesi Majid rezai Bahram Abdollahzadeh Ali Department of Mining and Metallurgical Engineering Amirkabir University of Technology Young Researchers and Elites Club Science and Research Branch Islamic Azad University Department of Mining Engineering University of Kashan

The phenomenological theory of sedimentation-thickening processes predicts the settling behavior of a flocculated suspension in dependence of two functions, the batch flux density function and the effective solid stress. These functions were determined using batch settling tests. The governing equations for sedimentation were then solved numerically for these functions and the predictions were compared to the experimental results from pilot scale thickener tests. Firstly, the continuous tests were performed in the plexiglass pilot thickener at different feed flow rates and discharge rates and the solid volume fraction of discharge, the bed height and the time were recorded for each condition. These tests were also simulated and it was observed that there is a good agreement between the results of continuous tests and the results of dynamic simulation. Secondly, the discontinuous tests were performed in the plexiglass pilot thickener at different feed flow rates with a discharge rate of zero. The bed formation rate was determined for each condition. These tests were also simulated and it was observed that there is a good agreement between the results of discontinuous tests and the results of simulation.

关键词： dynamic simulation dewatering thickener behavior pilot thickener validation

Bonded-particle model calibration using response surface methodology

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particuology 2017年第3期15卷 141-152页

作者： Sajjad Chehreghani Mohammad Noaparast Bahram rezai Sied Ziaedin Shafaei School of Mining University College of Engineering University of Tehran. 14395-515. Tehran Iran Department of Mining and Metallurgy Engineering. Amir Kabir University of Technology Tehran Iran

The bonded-particle model （BpM） is commonly used in numerical analysis of the mechanical behavior of rock samples. Constructing a BpM model requires specification of a number of microstructural parame- ters, including the parallel-bond tensile strength, parallel-bond cohesion strength, parallel-bond effective modulus, parallel-bond friction angle, and parallel-bond stiffness ratio. These parameters cannot be eas- ily measured in the laboratory or directly related to either measurable or physical material parameters. Hence, a calibration process is required to choose the values to be used in simulations of physical systems. In this study, response surface methodology along with the central composite design approach is used to calibrate BpMs. The sensitivities of the microparameters related to the uniaxial compressive strength （UCS） and elasticity modulus （i.e., the macroscopic responses of the models） are thoroughly scrutinized. Numerical simulations are performed to carefully assess the performance of the model. It is found that the elasticity modulus is highly correlated with the parallel-bond effective modulus. In addition, the parallel- bond tensile and cohesion strengths are the two most significant microparameters with a considerable effect on the UCS. The predicted values determined by the proposed approach are in good agreement with the observed values, which verifies the applicability of the proposed method.

关键词： Bonded-particle modelCalibrationResponse surface methodologyUniaxial compressive strength