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Influence of freeze-only and freezing-thawing cycles on splash erosion

International Soil and Water Conservation Research 2018年第4期6卷 275-279页

作者： Seyed Hamidreza Sadeghi mohammad bagher raeisi Zeinab Hazbavi Watershed Management Engineering Department Faculty of Natural ResourcesMember of Agrohydrology GroupTarbiat Modares UniversityNoor46417-76489Iran Watershed Management Engineering and Sciences Department of Watershed Management EngineeringFaculty of Natural ResourcesTarbiat Modares UniversityIran

Soil erosion is recognized as one of the most important types of land degradation in the world particularly in many developing countries like Iran. Water erosion is initiated by splash erosion triggered by raindrop impact. Understanding the process of splash erosion under freezing and thawing conditions is essential to unravel soil erosion mechanisms under temperate conditions leading to appropriate planning of soil and water conservation projects. The present study aimed to study the individual effects of freeze-only as well as freezing-thawing cycle on splash erosion in a loess soil from an erosion prone area in mountainous northern regions of Iran. The study was conducted under laboratory conditions using erosion plots. The erosion plots were subjected to freeze only and freeze-thawing treatments by simulating cold conditions using a large cooling compartment system specifically manufactured for this purpose. The splash erosion under a designed simulated rainfall (1.2mmmin-1 for 30 min) was then measured as upward, downward and net splash erosion in splash cups. The results showed that freeze only decreased the upward, downward and net splash erosion by 0.81 ± 0.43, 0.82 ± 0.29 and 0.85 ± 0.23% while freezing-thawing cycle decreased splash erosion to 0.93 ± 0.83, 0.61 ± 0.43 and 0.57 ± 0.36%. This may be attributed to temporary increase in soil strength and stability or surface sealing during freezing process leading to reduced splash erosion.

关键词： Experimental plots Freezing effects Rainfall simulation Soil detachment process

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Edge Coloring of Graphs with Applications in Coding Theory

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China Communications 2021年第1期18卷 181-195页

作者： Ghaffar raeisi mohammad Gholami Department of Mathematical Sciences Shahrekord UniversityShahrekordP.O.Box 115Iran

In this paper,a new type of edge coloring of graphs together with an algorithm for such an edge coloring is presented to construct some columnweight three low-density parity-check(LDPC)codes whose Tanner graphs are free of *** kind of edge coloring is applied on some well-known classes of graphs such as complete graphs and complete bipartite graphs to generate some column-weight 3 LDPC codes having flexibility in terms of code length and ***,the constructed(3;k)-regular codes with regularities k=4;5;:::;22 have lengths n=12;20;26,35;48;57;70;88;104;117;140;155;176;204;228;247;280;301;330;having minimum block length compared to the best known similar codes in the *** addition to linear complexity of generating such parity-check matrices,they can be considered as the base matrices of some quasi-cyclic(QC)LDPC codes with maximum achievable girth 18,which inherit the low-complexity encoder implementations of QC-LDPC *** results show that the QC-LDPC codes with large girth lifted from the constructed base matrices have good performances and outperform random codes,progressive edge growth LDPC codes,some finite fields and group rings based QC-LDPC codes and also have a close competition to the standard IEEE 802.16e(WiMAX)code.

关键词： low-density parity-check code edge coloring Quasi-cyclic LDPC code girth AWGN channel

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Enhanced removal of nitrate and phosphate from wastewater by Chlorella vulgaris: Multi-objective optimization and CFD simulation

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Chinese Journal of Chemical Engineering 2019年第3期27卷 639-648页

作者： mohammad bagher Sabeti mohammad Amin Hejazi Afzal Karimi Faculty of Chemical and Petroleum Engineering University of Tabriz Department of Food Biotechnology Branch for Northwest & West Region Agricultural Biotechnology Research Institute of Iran Agricultural Education and Extension Organization (AREEO) Department of Biotechnology Faculty of Advanced Technologies in Medicine Iran University of Medical Sciences

To enhance the efficiency of wastewater biotreatment with microalgae, the effects of physical parameters need to be investigated and optimized. In this regard, the individual and interactive effects of temperature, p H and aeration rate on the performance of biological removal of nitrate and phosphate by Chlorella vulgaris were studied by response surface methodology(RSM). Furthermore, a multi-objective optimization technique was applied to the response equations to simultaneously find optimal combinations of input parameters capable of removing the highest possible amount of nitrate and phosphate. The optimal calculated values were temperature of 26.3 °C, pH of 8 and aeration rate of 4.7 L·min^(-1). Interestingly, under the optimum condition, approximately 85% of total nitrate and 77% of whole phosphate were removed after 48 h and 24 h, respectively, which were in excellent agreement with the predicted values. Finally, the effect of baffle on mixing performance and, as a result, on bioremoval efficiency was investigated in Stirred Tank Photobioreactor(STP) by means of Computational Fluid Dynamics(CFD). Flow behavior indicated substantial enhancement in mixing performance when the baffle was inserted into the tank. Obtained simulation results were validated experimentally. Under the optimum condition, due to proper mixing in baffled STP, nitrate and phosphate removal increased up to 93% and 86%,respectively, compared to unbaffled one.

关键词： Nitrate Phosphate Nutrient removal Response surface methodology Stirred Tank Photobioreactor Computational Fluid Dynamics

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DYNAMICS OF KNOWLEDGE ACCUMULATION IN TECHNOLOGY FOLLOWER COUNTRIES: A SYSTEM DYNAMICS APPROACH

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Journal of Systems Science and Systems Engineering 2009年第3期18卷 312-340页

作者： Ehsan SHAFIEI mohammad-bagher GHOFRANI Yadollah SABOOHI Power and Energy Planning Department Ministry of Energy TehranIran Department of Energy Engineering Sharif University of Technology TehranIran Sharif Energy Research Inst. Sharif University of Technology TehranIran

In this paper the process of knowledge accumulation for a particular technology is studied. Two countries, say the technology follower and the technology frontier, are considered. The frontier＇s knowledge growth is determined by its R＆D efforts on the technology. The level of knowledge stock for the follower country is augmented by its R＆D activities for the technology and absorbing some of the external knowledge through spillover from the frontier. The extent to which the follower is able to exploit the external knowledge depends on technological gap, absorptive capacity, absorption time and degree of spillover. New concepts such as natural and enhanced degree of spillover, background and innovative knowledge and absorption speed are introduced in the present work to deeply explore the process of knowledge spillover. The factors influencing the knowledge development in the long term are simultaneously studied in an integrated structure provided by the System Dynamics approach. This framework shows the responses to the changes and provides the basis for examining the interactions among the variables over time.

关键词： Knowledge spillover technology follower absorptive capacity absorption speed,knowledge complexity system dynamics

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Sacrificial piles as a countermeasure against local scour around underwater pipelines

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Water Science and Engineering 2024年第2期17卷 187-196页

作者： Forough raeisi Seyed mohammad Ali Zomorodiann Masih Zolghadr Hazi mohammad Azamathulla Department of Water Engineering Shiraz UniversityShiraz ***Iran Department of Water Sciences Engineering Jahrom UniversityJahrom ***Iran Department of Civil and Environmental Engineering The University of the West IndiesSt.Augustine CampusTrinidad 331310Republic of Trinidad and Tobago

Local scour around pipelines crossing rivers or in marine environments is a significant *** can lead to failure of the pipelines resulting in environmental side effects and economic *** study developed an experimental method to reduce local scour around pipelines with a steady flow of clear water by installing cylindrical and cubical sacrificial *** sizes of sacrificial piles were examined in a linear *** piles were installed on the upstream side of the pipeline at three *** scour depth reduction rates below the pipeline were *** results showed that sacrificial piles could protect a pipeline from local scour.A portion of scoured sediment around the sacrificial piles was deposited beneath the *** sediment accumulation reduced the scour depth beneath the *** of the experimental results demonstrated that the size of piles(d),the spacing between piles,and the distance between the pipe and piles(Xp)were the variables that reduced the maximum scour beneath the pipeline with a diameter of *** the piles with d=0.40D and 0.64D,X_(p)=4OD was the optimal distance to install a group of piles,and cubical piles could mitigate scour more effectively than cylindrical piles under similar *** the piles with d=D,the greatest reduction in scour depth was achieved at X_(p)=50D with any desired spacings between piles,and cylindrical piles in this dimension could protect the pipeline against scour more effectively than cubical piles.

关键词： Clear water River crossing pipeline Local scour Self-burial process Sediment transport

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Mesoscale eddies and their dispersive environmental impacts in the Persian Gulf

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Chinese Physics B 2020年第8期29卷 363-371页

作者： Amin raeisi Abbasali Bidokhti Seyed mohammad Jafar Nazemosadat Kamran Lari Faculty of Natural Resources and Environment Science and Research BranchIslamic Azad UniversityTehran ***Iran Geophysics Institute University of TehranTehran ***Iran Department of Water Engineering Oceanic and Atmospheric Research CenterShiraz UniversityShiraz ***Iran Department of Physical Oceanography Faculty of Marine Science and TechnologyTehran North BranchIslamic Azad UniversityTehran ***Iran

As the mesoscale eddies in oceans and semi-enclosed seas are significant in horizontal dispersion of pollutants,we investigate the seasonal variations of these eddies in the Persian Gulf(PG)that are usually generated due to seasonal winds and baroclinic *** sea surface height(SSH)data from 2010 to 2014 of AVISO are used to identify and track eddies,using the SSH-based *** seasonal horizontal dispersion coefficients are estimated for the PG,using the properties of *** results show an annual mean of 78 eddies with a minimum lifetime of one *** of the eddies are predominantly cyclonic(59.1%)and have longer lifetimes and higher diffusion coefficients than the anti-cyclonic *** eddy activity is higher in warm seasons,compared to that of cold *** locations with high eddy diffusion coefficients are high-risk areas by using maps of horizontal eddy diffusion coefficients,perilous times and locations of the release of pollutants are specified to be within the longitude from 51.38°E to 55.28°*** mentioned areas are located from the Strait of Hormuz towards the northeast of the PG,closer to Iranian ***,July can be considered as the most dangerous time of pollution release.

关键词： Persian Gulf mesoscale eddies marine pollution horizontal eddy diffusion coefficient

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The mediating role of environmental emotions in transition from knowledge to sustainable use of groundwater resources in Iran's agriculture

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International Soil and Water Conservation Research 2018年第2期6卷 143-152页

作者： Aliakbar raeisi Masoud Bijani mohammad Chizari Department of Agricultural Extension and Education College of AgricultureTarbiat Modares University(TMU)Tehran ***Iran

The excessive use of groundwater resources has created numerous environmental consequences in Iran. Many water experts believe that this crisis can be overcome by fostering sustainable environmental behavior in the utilization of groundwater resources and increasing the farmers' environmental knowledge, attitude and emotions. The objective of this study was to investigate transformation of en-vironmental knowledge to sustainable use of groundwater resources through the analysis of the med-iating role of environmental emotions in Iran's agriculture. This research was carried out via a survey technique within the category of descriptive-correlation and causal-relational research. All the wheat producing farmers of Sistan and Baluchestan Province, which is a clear example of critical conditions for groundwater resources in Iran (N=168,873), constituted the statistical population of the study of whom 384 participants were selected using a stratified random sampling method. The research instrument was a questionnaire whose validity was confirmed by a panel of professionals in agricultural extension, education and water management. The reliability of the items of the questionnaire was also evaluated via a pilot study and Cronbach's alpha (0.70≤α≤0.84). The results of the causal analysis indicated that environmental knowledge (β=0.309) and environmental emotions (β=0.565) have the significant in-fluence on sustainable environmental behavior in the utilization of groundwater among wheat farmers. Therefore, it can be said environmental emotions is an important mediating factor for potentially im-proving water stakeholders' sustainable environmental behavior.

关键词： Sustainable environmental behavior (SEB) Groundwater Environmental knowledge (EK) Environmental emotions (EE) Causal analysis

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Evaluation of renewable energies production potential in the Middle East:confronting the world’s energy crisis

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Frontiers in Energy 2020年第1期14卷 42-56页

作者： Hamid BAHRAMPOUR Amir Khosro BEHESHTI MARNANI mohammad bagher ASKARI mohammad Reza BAHRAMPOUR Department of Mechanical Engineering Islamic Azad UniversityScience and Research BranchTehran14515-775Iran Department of Chemistry Payame Noor UniversityTehran19395-3697Iran Department of Physics Payame Noor UniversityTehran19395-3697Iran Department of Materials Science and Engineering Payame Noor UniversityTehran19395-3697Iran

Oil and fossil fuels,the main source of energy in the Middle East have obviously the most destructive effects on the environment and public *** developed countries of the Middle East are faced with the crisis and energy *** paper is about evaluating the energy demand/consumption in the Middle ***,the position of energy consumption in the world and the Middle East is ***,the evaluation of the current potential of clean energy production from renewable energies is ***,according to related maps,charts and information presented for the condition of renewable energy which has been approved by the countries of the Middle East,the greatest places in some countries of this region are introduced and discussed.

关键词： Middle East countries renewable energy fossil fuels energy crisis

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Fe^(3+)-Doped Anatase TiO_2 Study Prepared by New Sol-Gel Precursors

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Chinese Physics Letters 2018年第2期35卷 102-106页

作者： Bahram Khoshnevisan mohammad bagher Marami Majid Farahmandjou Department of Physics Faculty of ScienceUniversity of Kashan Departments of Physics Varamin Pishva BranchIslamis Azad University

FeTi_1-O_2（= 0.00,0.05,0.10） nanocomposites are synthesized using a sol-gel method involving an ethanol solvent in the presence of ethylene glycol as the stabilizer,and acetic acid as the chemical *** structural and optical analyses are studied to reveal their physicochemical *** the x-ray diffractometer（XRD）analysis,the size of the nanoparticles（NPs） is found to be 18-32 nm,where the size of the NPs decreases down to 18 nm when Fe impurity of up to 10% is added,whereas their structure remains *** results also indicate that the structure of the NPs is tetragonal in the anatase *** Fourier transform infrared spectroscopy analysis suggests the presence of a vibration bond（Ti-O） in the *** photoluminescence analysis indicates that the diffusion of Fe^（3＋） ions into the TiO_2 matrix results in a decreasing electron-hole recombination,and increases the photocatalytic properties,where the best efficiency appears at an impurity of10%.The UV-diffuse reflection spectroscopy analysis indicates that with the elevation of iron impurity,the band gap value decreases from 3.47 eV for the pure sample to 2.95 eV for the 10 mol% Fe-doped TiO_2 NPs.

关键词： Fe Doped Anatase TiO2 Study Prepared by New Sol-Gel Precursors TiO

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Investigation of the degradation rate of electron beam processed and friction stir processed biocompatible ZKX50 magnesium alloy

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Journal of Magnesium and Alloys 2022年第3期10卷 768-781页

作者： Fatemeh Iranshahi mohammad bagher Nasiri Fernando Gustavo Warchomicka Christof Sommitsch Joining and Forming Institute of Materials ScienceGraz University of TechnologyKopernikusgasse 24/IGraz 8010Austria

Together with the mechanical properties,the degradation rate is an important factor for biodegradable *** ZKX50 Mg alloy is a suitable candidate to be used as a biodegradable implant due to its favorable biocompatibility and mechanical *** research investigates the degradation rate and corrosion behavior of the ZKX50 as a function of the microstructure constituents and their *** grain refinement is the main strengthening mechanism for the ZKX50,the effect of the microstructure refinement on the corrosion rate was studied by applying electron beam processing(EBP)and friction stir processing(FSP)on the ZKX50 cast *** study the effect of the microstructure constituents and their morphology a subsequent solution heat treatment(HT)was applied to the processed *** results show that the EBP and FSP lead to a uniform and remarkably refined microstructure of the ZKX50 alloy and homogeneous distribution of the intermetallic *** results of electrochemical corrosion tests together with the microstructure characterization show that microgalvanic corrosion is the predominant mechanism that occurs between the Ca2Mg6Zn3 intermetallic phase andα-Mg *** to the results attained through the electrochemical tests,the EBPed-HT ZKX50 alloy shows higher corrosion resistance compared to all other conditions immersed in 0.5 wt.%NaCl *** dissolution and spheroidizing of Ca2Mg6Zn3 particles during the solution heat treatment provides higher corrosion resistance mainly by decreasing the microgalvanic *** microstructure of the heat-treated samples does not show a significant grain coarsening which can degrade the enhancement of the mechanical properties achieved by the EBP and FSP.

关键词： Magnesium alloys Electron beam processing Friction stir processing Corrosion Biodegradable metals.

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