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Mapping the current and future distributions of Onosma species endemic to Iran

Journal of Arid Land 2020年第6期12卷 1031-1045页

作者： Farzaneh KHAJOEI NASAB ahmadreza mehrabian Hossein MOSTAFAVI Department of Plant Sciences and Biotechnology Faculty of Life Sciences and BiotechnologyShahid Beheshti UniversityTehran ***Iran Department of Biodiversity and Ecosystems Management Environmental Sciences Research InstituteShahid Beheshti UniversityTehran ***Iran

Climate change may cause shifts in the natural range of species especially for those that are geographically restricted and/or endemic species.In this study,the spatial distribution of five endemic and threatened species belonging to the genus Onosma(including O.asperrima,O.bisotunensis,O.kotschyi,O.platyphylla,and O.straussii)was investigated under present and future climate change scenarios:RCP2.6(RCP,representative concentration pathway;optimistic scenario)and RCP8.5(pessimistic scenario)for the years 2050 and 2080 in Iran.Analysis was conducted using the maximum entropy(MaxEnt)model to provide a basis for the protection and conservation of these species.Seven environmental variables including aspect,depth of soil,silt content,slope,annual precipitation,minimum temperature of the coldest month,and annual temperature range were used as main predictors in this study.The model output for the potential habitat suitability of the studied species showed acceptable performance for all species(i.e.,the area under the curve(AUC)>0.800).According to the models generated by MaxEnt,the potential current patterns of the species were consistent with the observed areas of distributions.The projected climate maps under optimistic and pessimistic scenarios(RCP2.6 and RCP8.5,respectively)of 2050 and 2080 resulted in reductions and expansions as well as positive range changes for all species in comparison to their current predicted distributions.Among all species,O.bisotunensis showed the most significant and highest increase under the pessimistic scenario of 2050 and 2080.Finally,the results of this study revealed that the studied plant species have shown an acute adaptability to environmental changes.The results can provide useful information to managers to apply appropriate strategies for the management and conservation of these valuable Iranian medicinal and threatened plant species in the future.

关键词： climate change endemic plant MaxEnt species distribution modeling RCP2.6 RCP8.5 Iran

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Vegetation Mapping of the Mond Protected Area of Bushehr Province(South-west Iran)

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Journal of Integrative Plant Biology 2009年第3期51卷 251-260页

作者： ahmadreza mehrabian Alireza Naqinezhad Abdolrassoul Salman Mahiny Hossein Mostafavi Homan Liaghati Mohsen Kouchekzadeh Department of Biodiversity and Ecosystems Management Environmental Sciences Research InstituteShahid Beheshti University Department of Biology Faculty of SciencesUniversity of Mazandaran College of the Environment Gorgan University of Agriculture and Natural Resources Sciences Department of Ecological Agriculture Environmental Sciences Research InstituteShahid Beheshti University Department of Planning and Design of Environment Environmental Research InstituteShahid Beheshti University

Arid regions of the world occupy up to 35% of the earth＇s surface, the basis of various definitions of climatic conditions, vegetation types or potential for food production. Due to their high ecological value, monitoring of arid regions is necessary and modern vegetation studies can help in the conservation and management of these areas. The use of remote sensing for mapping of desert vegetation is difficult due to mixing of the spectral reflectance of bright desert soils with the weak spectral response of sparse vegetation. We studied the vegetation types in the semiarid to arid region of Mond Protected Area, south-west Iran, based on unsupervised classification of the Spot XS bands and then produced updated maps. Sixteen map units covering 12 vegetation types were recognized in the area based on both field works and satellite mapping. Halocnemum strobilaceum and Suaeda fruticosa vegetation types were the dominant types and Ephedra foliata, Salicornia europaea-Suaeda heterophylla vegetation types were the smallest. Vegetation coverage decreased sharply with the increase in salinity towards the coastal areas of the Persian Gulf. The highest vegetation coverage belonged to the riparian vegetation along the Mond River, which represents the northern boundary of the protected area. The location of vegetation types was studied on the separate soil and habitat diversity maps of the study area, which helped in final refinements of the vegetation map produced.

关键词： arid region coast line halophytes island vegetation Iran Persian Gulf vegetation mapping vegetation types.

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Investigating the influential post-disaster factors in determining the optimal location of shelters:A case study,Sarpol-e Zahab,Kermanshah province,Iran

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Frontiers of Architectural Research 2022年第5期11卷 846-864页

作者： Ali Moghri ahmadreza Khalili Department of Art and Architecture Islamic Azad UniversityTehranIran

A proper location is one of the most influential factors in shelter performance.Although considerable research focuses on finding a suitable site for temporary shelters,only a few address the effect of post-disaster circumstances on discovering the optimal location.This study primarily aims to investigate the influential factors in determining a suitable place for temporary shelters after a crisis.Therefore,an algorithm is proposed.This algorithm is achieved by analyzing and computing the post-crisis urban route and facility accessibility based on photogrammetric photographs taken by an unmanned aerial vehicle/satellite.

关键词： Locating Temporary shelter Crisis areas Computing Photogrammetric photos

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Strengthening of reinforced concrete beams using fiberreinforced cementitious matrix systems fabricated with custom-designed mortar and fabrics

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Frontiers of Structural and Civil Engineering 2023年第7期17卷 1100-1116页

作者： ahmadreza RAMEZANI Mohammad Reza ESFAHANI Javad SABZI Faculty of Engineering Ferdowsi University of MashhadMashhadIran

The performance of a new fiber-reinforced cementitious matrix(FRCM)system developed using custom-designed mortar and fabrics is investigated in this study.The behavior of this system is evaluated in terms of both the flexural and shear strengthening of reinforced concrete beams.Eight beams are designed to assess the effectiveness of the FRCM system in terms of flexural strengthening,and four specimens are designed to investigate their shear behavior.The parameters investigated for flexural strengthening are the number of layers,span/depth ratio,and the strengthening method.Unlike previous studies,custom fabrics with similar axial stiffness are used in all strengthening methods in this study.In the shear-strengthened specimens,the effects of the span/depth ratio and strengthening system type(fiberreinforced polymer(FRP)or FRCM)are investigated.The proposed FRCM system exhibits desirable flexural and shear strengthening for enhancing the load capacity,provides sufficient bonding with the substrate,and prevents premature failure modes.Considering the similar axial stiffness of fabrics used in both FRCM and FRP systems and the higher load capacity of specimens strengthened by the former,cement-based mortar performs better than epoxy.

关键词： fiber-reinforced cementitious matrix flexural strengthening shear strengthening carbon fiber-reinforced polymer shear span

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Physical model simulation of rock-support interaction for the tunnel in squeezing ground

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Journal of Rock Mechanics and Geotechnical Engineering 2022年第1期14卷 82-92页

作者： Ketan Arora Marte Gutierrez ahmadreza Hedayat Civil and Environmental Engineering Colorado School of MinesGoldenCO80401USA

The existence of squeezing ground conditions can lead to significant challenges in designing an adequate support system for tunnels.Numerous empirical,observational and analytical methods have been suggested over the years to design support systems in squeezing ground conditions,but all of them have some limitations.In this study,a novel experimental setup having physical model for simulating the tunnel boring machine(TBM)excavation and support installation process in squeezing clay-rich rocks is developed.The observations are made to understand better the interaction between the support and the squeezing ground.The physical model included a large true-triaxial cell,a miniature TBM,laboratoryprepared synthetic test specimen with properties similar to natural mudstone,and an instrumented cylindrical aluminum support system.Experiments were conducted at realistic in situ stress levels to study the time-dependent three-dimensional tunnel support convergence.The tunnel was excavated using the miniature TBM in the cubical rock specimen loaded in the true-triaxial cell,after which the support was installed.The confining stress was then increased in stages to values greater than the rock’s unconfined compressive strength.A model for the time-dependent longitudinal displacement profile(LDP)for the supported tunnel was proposed using the tunnel convergence measurements at different times and stress levels.The LDP formulation was then compared with the unsupported model to calculate the squeezing amount carried by the support.The increase in thrust in the support was backcalculated from an analytical solution with the assumption of linear elastic support.Based on the test results and case studies,a recommendation to optimize the support requirement for tunnels in squeezing ground is proposed.

关键词： Squeezing ground Tunnel support system Longitudinal displacement profile Rock-support interaction

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Effect of fiber hybridization on energy absorption and synergy in concrete

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Frontiers of Structural and Civil Engineering 2019年第6期13卷 1338-1349页

作者： ahmadreza RAMEZANI Mohammad Reza ESFAHANI Department of Civil Engineering Ferdowsi University of MashhadMashhad 91775-1111Iran

In the present study,steel and polypropylene(PP)fibers have been utilized with the intent of obtaining hybrid fiber-reinforced concrete(HFRC)with desirable mechanical properties.An attempt has been made to scrutinize the properties of HFRC with the main concentration being on energy absorption characteristics of concrete and the efficacy of fiber hybridization in producing synergy.Accordingly,a total of 180 specimens,representing 20 different mixtures have been cast and evaluated through compressive,split tensile,and flexural tests.The relevant flexural toughness of the specimens was calculated using ASTM C1018,ASTM Cl 609,JSCE,and PCS methods,and the effectiveness of these methods was evaluated based on the experimental results.It was observed that steel fibers are more effective in the improvement of flexural toughness in the presence ofPP fibers.Furthermore,synergy associated with the combination of fibers at different stages of deflection of the beam specimens was observed and analyzed.

关键词： hybrid fiber-reinforced concrete synergy toughness steel fibers polypropylene fibers

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Ultrasonic imaging of microscale processes in quartz gouge during compression and shearing

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Journal of Rock Mechanics and Geotechnical Engineering 2020年第6期12卷 1137-1151页

作者： Amin Gheibi ahmadreza Hedayat Colorado School of Mines GoldenUSA

Active ultrasonic monitoring in rock joints and gouge materials has the potential to detect the signatures of shear failure for a wide range of sliding modes,from slow and stable movements to fast and unstable sliding.While these collected measurements currently are being used to identify the seismic precursors to shear failure in rock joints and gouge materials,the underlying physical processes and contact scale mechanisms that control the changes in ultrasonic wave attributes are still poorly understood.To address this knowledge gap,this paper aims to investigate the relationship between the variations in ultrasonic wave attributes and the underlying particle scale mechanisms during both compression and shearing.Our double direct shear experiments were coupled with ultrasonic wave propagation measurements on granular quartz gouges,in which the gouge layers were sheared under different sliding velocities and constant normal stress conditions.Simultaneously,ultrasonic waveforms were continuously recorded during shearing with a fast data acquisition system and three pairs of ultrasonic wave transducers embedded at the two sides of the gouge layers.Different particle comminution mechanisms were observed from the non-uniform distribution of normal and shear stresses through the changes in ultrasonic transmissivity and scanning electron microscope(SEM)images.Our results show that the signatures of the geometry-and time-dependent variations of the inter-particle contact quality and pore volume changes with sliding velocity and slip accumulation were clearly captured from the variations in the transmitted wave amplitude and the dominant frequency,respectively.In addition,we found that variations in dominant frequency corresponded to dilation and compaction of the granular gouge layer during compression as well as stable and unstable sliding.Our results therefore confirmed that nondestructive acoustic techniques are capable of capturing a variety of micromechanical processes during fault gouge deformation and may prove

关键词： Granular material Ultrasonic investigation Particle comminution Compaction and dilation

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Theoretical Study of Halogen Effect in Isomerization of 2-Halo-[9]-annulen Anion at the DFT Level

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Chinese Journal of Structural Chemistry 2011年第6期30卷 906-912页

作者： ahmadreza Bekhradnia SATTAR Arshadi Pharmaceutical Sciences Research Center Department of Medicinal ChemistryMazandaran University of Medical Sciences Department of Chemistry Payame Noor UniversityBehshahr Unit

Cis-trans isomerization of [9]-annulenanion（1） and its 2-fluoro-,2-chloro-and 2-bromo-derivatives（2,3 and 4,respectively） were investigated at the HF/6-31G＊ and B3LYP/6-311＋＋G＊＊ levels of theory.Cis,cis,cis,cis structures appear more stable than their corresponding cis,cis,cis,trans-isomers.The relative height of energy barriers for cis-trans isomerization is：2cis 〉1cis 〉3cis〉 4cis.This trend for the reverse trans-cis isomerization follows the electronegativity of the substituent at C-2（2trans 3trans 4trans 1trans）.

关键词： isomerization halogen effects -annulen anion DFT

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Characteristics of the First Occurrence of Jurassic Petroleum in the Zagros Basin, Iran

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Acta Geologica Sinica(English Edition) 2018年第6期92卷 2280-2296页

作者： Sadouni JALIL Rabbani ahmadreza AmirKabir University of Technology Faculty of Petroleum Engineering

After two well tests in the Asmari well#A, located in the North Dezful zone, it was concluded that in the Jurassic Mus/Alan/Neyriz and Upper Sargelu reservoirs, highly mature colorless oil and gas were trapped, including 4%-6% H2 S. The alternation of Garau shale and the Gotnia anhydrite seal was so efficient that it did not allow the upward migration of petroleum from Jurassic reservoirs to higher levels. Descriptive ratios, chromatograms, pick correlation and cross plots demonstrated that the oil and gas have been derived from a TOC-enriched sequence, consisting of the base of the Garau and the top of the Sargelu Formations. This highly organic matter-rich sequence is traceable as an oil shale in other parts of the North Dezful zone, such as the Gashun section. The petroleum accumulations in both reservoirs are identical, have the same maturity and the same source. Diagrams of δ13 C2 versus δ13 C3, δ13 C1 versus wetness of gas(C1/C2+C3) and δ13 C1 versus δDC1 suggest that the gas is derived from a highly mature source. There are indications of TSR effects on the original petroleum that could have changed the volumetric and isotopic composition of the oil and gas. This result requires more careful study of the petroleum components to be undertaken.

关键词： isotope wetness enrichment migration oil shale

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Topomerization of 2-Halo-[9] Annulen Anion at the DFT Level

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Chinese Journal of Structural Chemistry 2011年第10期30卷 1509-1516页

作者： SATTAR Arshadi ahmadreza Bekhradnia Department of Chemistry Payame Noor University Pharmaceutical Sciences Research Center Department of Medicinal ChemistryMazandaran University of Medical Sciences

Topomerization of [9] annulen anion （1） and its 2-fluoro-, 2-chloro- and 2- bromo-defivatives （2, 3 and 4, respectively） are studied at the HF/6-31G＊ and B3LYP/6-31 1＋＋G＊＊ levels of theory. The relative ease of topomerization is dependent on the charge distribution and planarity of the ground state and the transition state of 9-membered rings as well as the size and electronegativity of halogen substituent. Consequently, the endo-2-halo-[9] annulen anion topomers become unstable and easily convert to related exo-topomers. Hence, according to the DFT calcu- lations, the order of topomerization energy barrier for endo = exo topomerization is lendo 〉 2endo 〉 3endo.

关键词： topomerization substiuent effects 2-halo- annulen anion DFT

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