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The effect of K2SiF6 on the MgH2 hydrogen storage properties

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Journal of Magnesium and Alloys 2020年第3期8卷 832-840页

作者： M.Ismail M.S.yahya n.A.Sazelee n.A.Ali F.A.Halim Yap n.S.Mustafa Energy Storage Research Group Faculty of Ocean Engineering Technology and InformaticsUniversity Malaysia Terengganu21030 Kuala TerengganuMalaysia Faculty of Innovative Design and Technology Universiti Sultan Zainal AbidinGong Badak Campus21300 Kuala NerusTerengganuMalaysia

The catalytic effect of K2SiF6 on MgH2 was first timely *** MgH2+5 wt.%K2SiF6 was prepared via the ball milling *** catalyst had lessened the initial decomposition temperature by 134℃ and 48℃ as compared to both pristine and milled MgH2 samples,*** 2 minutes,4.5 wt.%of hydrogen was absorbed(250℃)by the doped composite,which was 0.8 wt.%higher than the milled ***,for the desorption kinetics(320℃,1 atm),the amount of desorbed hydrogen was increased by 2.4 wt.%and 2.3 wt.%for the first 10 and 20 ***,contracting volume and Johnson-Mehl-Avrami models were used to analyse the kinetics *** decomposition activation energy calculated based on Kissinger equation was 114 kJ/*** for the active species,Mg2Si,MgF2 and KH were formed during the heating *** active species are speculated to be responsible for the improvement of the hydrogenation properties of the composite.

关键词： Catalytic effect Magnesium hydride Hydrogen storage Sorption properties Contracting volume model

Comparison of soil fertility of Acer insigne, Quercus castaneifolia, and Pinus brutia stands in the Hyrcanian forests of Iran

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应用与环境生物学报 2014年第5期20卷 899-905页

作者： yahya Kooch Zohre Zoghi Department of Forestry Faculty of Natural Resources Tarbiat Modares University

Trees species have different effects on soil properties and nutrients. Plantation as a management strategy for soil productivity retention and the prevention of destruction can be effective in the continuity of forest productivity. After 21 years, the effects of the maple(Acer velutinum Bioss.), oak(Quercus castaneifolia C. A. Mey.), and red pine(Pinus brutia Ten.) stands on soil fertility were assessed in the Sari region(northern Iran). Soil was sampled at depths of 0-10, 10-20, 20-30, and 30-40 cm at all stands using a core soil sampler with an 81 cm2 cross section. Soil texture, pH, organic carbon(C), total nitrogen(n), available phosphorus(P), potassium(K), calcium(Ca), and magnesium(Mg) for all samples were measured in the laboratory. Our findings showed that the planted stands significantly affected soil physicochemical properties. Statistical comparisons revealed that the highest and lowest levels of n, P, K, Ca, and Mg in soil occurred in the maple and red pine stands, respectively. Measurements of soil fertility showed that fertility decreased in relation to increased soil depth, with significant differences depending on soil depth. Our results suggest that to rehabilitate degraded natural forests, at least in northern Iran, the plantation of suitable native broad-leaved species can be recommended for forestation plan management.

关键词： plantation needle-leaved species broad-leaved depth

Soil functional indicators in mixed beech forests are clearly species-specifi c

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Journal of Forestry Research 2023年第4期34卷 1033-1049页

作者： yahya Kooch neda Ghorbanzadeh Samaneh Hajimirzaaghaee Markus Egli Faculty of natural Resources&Marine Sciences Tarbiat Modares UniversityNoor 46417-76489MazandaranIran Faculty of natural Resources University of GuilanSowmeh Sara 4432-3136GuilanIran Faculty of natural Resources University of Agricultural Sciences and Natural ResourcesSariIran Department of Geography University of ZürichZurichSwitzerland

Beech stands are considered part of the ancient forest ecosystems in the northern *** mixed stands in beach forest ecosystems,the type of associated tree species can signifi cantly aff ect soil functions,but their infl uence on microbial activity,nutrient cycling and belowground properties is ***,we considered forest patches in northern Iran that are dominated by diff erent tree species:Fagus orientalis Lipsky,Quercus castaneifolia ***.,Pterocarya fraxinifolia(Lam.),Tilia begonifolia Stev.,Zelkova carpinifolia Dippe,Acer cappadocicum Gled,Acer velutinum Boiss.,Fraxinus excelsior L.,Carpinus betulus L.,and Alnus subcordata *** each forest patch–tree species,litter and soil samples(25×25×10 cm,100 of each)were analyzed for determine soil and litter properties and their relationship with tree *** litter decomposition rate during a 1-year experiment was also determined.A PCA showed a clear diff erence between selected litter and soil characteristics among tree ***,***,***,***,***,***,and *** enhanced soil microbial biomass of carbon,whereas patches with ***,*** and *** had faster litter decomposition and enhanced biotic activities and C and n ***,soil function indicators were species-specifi c in the mixed beech ***(a n-fi xing species),*** and *** were main drivers of microbial activities related to nutrient cycling in the old-growth beech forest.

关键词： Old-growth forest Deciduous tree species Soil fertility Microbial activities Carbon and nitrogen cycle

Isolation and identification of desert habituated arbuscular mycorrhizal fungi newly reported from the Arabian Peninsula

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Journal of Arid Land 2014年第4期6卷 488-497页

作者： Sarah SYMAnCZIK Janusz BLASZKOWSKI Sally KOEGEL Thomas BOLLER Andres WIEMKEn Mohamed n AL-yahya'EI Zurich Basel Plant Science Center Institute of BotanyUniversity of Basel Department of Plant Protection West Pomeranian University of Technology Soil and Water Research Center. Ministry of Agriculture and Fisheries Department of Aridland Agriculture College of Food and AgricultureUnited Arab Emirates University

Arbuscular mycorrhizal fungi（AMF） are known to facilitate the growth and vigour of many plants, particularly in arid ecosystems. In a survey of AMF in a date palm plantation and two natural sites of a desert in Oman, we generated many single spore-derived cultures of AMF. We identified a number of these isolates based on spore morphotyping and molecular phylogenetic analysis using the sequence of the LSU-rDnA. Here, we presented the characteristics of four species of AMF recovered, namely Claroideoglomus drummondii, Diversispora aurantia, Diversispora spurca and Funneliformis africanum. The four species have been described previously, but for the Arabian Peninsula they are reported here for the first time. Our endeavor of isolation and characterization of some AMF habituated to arid sites of Arabia represents a first step towards application for environmental conservation and sustainable agriculture in this region.

关键词： arbuscular mycorrhizal fungi biotechnology isolation characterization desert ecosystem Arabian Peninsula Oman

Studies on product distribution of alkali promoted iron catalyst in Fischer-Tropsch synthesis

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Journal of natural Gas Chemistry 2010年第1期19卷 31-34页

作者： Ali nakhaei Pour Masoud Zare yahya Zamani Research Institute of Petroleum Industry National Iranian Oil Company P.O.Box 14665-137 Tehran Iran

The dependencies of hydrocarbon product distributions of alkali promoted iron catalyst in Fischer-Tropsch synthesis have been studied. The concept of two superimposed Anderson-Schulz-Flory distributions has been applied for the representation of the effects of Mg, La and Ca promoters on product distributions. The FTS performance of the catalysts was tested in a fixed bed reactor under the conditions 563 K, 1.7 MPa, H2/CO = 1 and space velocities 4.86 and 13.28 nl·h^-1·gFe^-1. The results indicate that appropriate amounts of these promoters enhance the break in ASF distributions in the order Ca 〉 Mg 〉 La because of the rising of the catalyst surface basicity.

关键词： chain length distribution Fischer-Tropsch synthesis Fe catalyst

Effects of Pits and Mounds Following Windthrow Events on Soil Features and Greenhouse Gas Fluxes in a Temperate Forest

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Pedosphere 2015年第6期25卷 853-867页

作者： yahya KOOCH Sakineh Mollaei DARABI Seyed Mohsen HOSSEInI Department of Forestry Faculty of Natural Resources & Marine SciencesTarbiat Modares University

Pit and mound micro-relief(resultant microsites from trees uprooted by windthrow) could have regimes of microclimate and soil features that differ from areas of undisturbed soil. In an attempt to provide a comprehensive evaluation of the significance of pits and mounds on soil features and also the dynamics of greenhouse gas(GHG) fluxes at local scale, this study was carried out in a reserved area of Darabkola forest in Mazandaran Province, northern Iran. The age of a pit and mound was considered equal to the degree of decay of the blown down tree. Three microsites were distinguished, consisting of pit bottom(PB), mound top(MT) and undisturbed area(UA). Soil samples were taken at 0–15 and 15–30 cm depths from all microsites and analysed for soil physical, chemical and biological features. Our findings suggested that in context of forest ecology, pits and mounds following windthrow events should be considered as an effective factor influencing soil features(i.e., density, texture, water content, p H, organic C, total n, available nutrients and earthworm density/biomass) and especially GHG fluxes. Results showed that MT acted as a sink for n2O(-0.010 mg n2 O m-2d-1) and CH4(-0.257 mg CH4m-2d-1) fluxes and also produced lower CO2 concentrations(0.095 mg CO2 m-2d-1) than PB(0.207 mg CO2 m-2d-1) and UA(0.098 mg CO2 m-2d-1). As a consequence, a separation into pits/mounds would be important for a precise budgeting of greenhouse gases.

关键词： carbon dioxide, methane microsite, nitrous oxide oriental beech, uprooted tree

Downed logs improve soil properties in old-growth temperate forests of northern Iran

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Pedosphere 2020年第3期30卷 378-389页

作者： negar MOGHIMIAn Seyed Gholamali JALALI yahya KOOCH Ana REY Faculty of natural Resources&Marine Sciences Tarbiat Modares UniversityNoor 46417-76489Iran Department of Biogeography and Global Change National Museum of Natural History(MNCN)Spanish Scientific Council(CSIC)C/Serrano 115bisMadrid 28006(Spain

Dead trees, particularly downed logs, play an important role in the dynamics of forest ecosystem. Contribution of decaying wood to C and nutrient pools of forest soils depends on the tree species and degree of wood decay. However, the extent to which the downed logs affect the soil properties of temperate forests has rarely been evaluated. In this study, a mixed beech forest was selected in Liresar region of Mazandaran Province, northern Iran, to investigate if and how the presence of downed logs affected soil quality and function by comparing soils underneath degraded logs and nearby soils of the two dominant tree species(beech and hornbeam). We then explored how these effects occurred as downed logs decomposed by comparing the woods of both tree species at four degrees of decomposition. Degree of decay of downed logs was classified into four classes(DC1–DC4). Eight dead trees of each tree species were selected at the center of each sample plot. Three composite soil samples underneath each decaying log and 100 cm away from a decaying log were collected at two soil depths(0–15 and 15–30 cm) to analyze soil main physicochemical properties and microbial activity. The results revealed that downed logs affected soil physical(5% wetter than control soils), chemical(2% lower pH, 100% increase in organic C and total n in the case of hornbeam, and 2% increase in P), and biological characteristics(soil microbial respiration enhanced by 10%, and microbial biomass C 620 and 351.5 mg kg-1 and microbial biomass n 66.47 and 32.18 mg kg-1, respectively, in the cases of beech and hornbeam), thus resulting in significantly different soil microsites from those without downed logs. Presence of downed logs increased soil microbial activity and soil fertility as wood decayed. Thus, the presence of downed logs is an important factor influencing forest soils and should be taken into consideration in forest management practices.

关键词： beech course woody debris dead tree decay degree hornbeam soil microbial activity soil physicochemical properties

Application of dynamic model to predict some inside environment variables in a semi-solar greenhouse

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Information Processing in Agriculture 2018年第2期5卷 279-288页

作者： Behzad Mohammadi Seyed Faramarz Ranjbar yahya Ajabshirchi Department of Mechanical Engineering Mechanical Engineering FacultyUniversity of TabrizIran Department of Biosystems Engineering Faculty of AgricultureUniversity of TabrizIran

Greenhouses are one of the most effective cultivation methods with a yield per cultivated area up to 10 times more than free land cultivation but the use of fossil fuels in this production field is very *** greenhouse environment is an uncertain nonlinear system which classical modeling methods have some problems to solve *** are many control methods,such as adaptive,feedback and intelligent control and they require a precise ***,many modeling methods have been proposed for this purpose;including physical,transfer function and black-box *** objective of this paper is to modeling and experimental validation of some inside environment variables in an innovative greenhouse structure(semi-solar greenhouse).For this propose,a semi-solar greenhouse was designed and constructed at the north-West of Iran in Azerbaijan Province(38°10′n and 46°18′E with elevation of 1364 mabove the sea level).The main inside environment factors include inside air temperature(Ta)and inside soil temperature(Ts)were collected as the experimental data *** dynamic heat transfer model used to estimate the temperature in two different points of semi-solar greenhouse with initial *** results showed that dynamic model can predict the inside temperatures in two different points(Ta and Ts)with RMSE,MAPE and EF about 5.3C,10.2% and 0.78% and 3.45C,7.7%and 0.86%,respectively.

关键词： Semi-solar greenhouse Dynamic model Commercial greenhouse

Effects of Increasing Tungsten on Structural,Elastic and Optical Properties of xWO_3-(40-x)Ag_2O-60Te_2O Glass System

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Journal of Materials Science & Technology 2015年第1期31卷 83-90页

作者： MM.Umair A.K.yahya M.K.Halimah H.A.A.Sidek School of Physics and Materials Studies Universiti Teknologi MARA Department of Physics Faculty of ScienceUniversiti Putra Malaysia

Ternary teiiurite glasses with composition of xWO3（40-x）Ag2O-60TeO2（x=0-40 mol%） have been prepared by melt-quenching *** and optical properties of the glass system were obtained by ultrasonic velocity measurements and UV-vis spectroscopy,respectively,while structural investigation was carried out by using Raman *** longitudinal and shear velocities,vLand vsshowed large increase at x from 0 to 20 mol%before decrease with further addition of *** longitudinal modulus CLand shear modulus μ bulk modulus KeYoung’s modulus Vand Debye temperature θDshowed similar behaviors to both *** large increase of the elastic moduli at x from 0 to 20 mol%is suggested to be due to the increase in WO6octahedral unit structure indicating the increase of bridging oxygen（BO） and formation of stronger Te-O-W bonds compared to Te-O-Te *** the other hand,forx> 20 mol%,the decrease in the elastic moduli was due to the increase of non-bridging oxygen（nBO） as a result of formation of WO4tetrahedral via breaking Te-O-W *** analysis by using bulk compression and ring deformation models showed a slight decrease in the ratio of ideal bulk modulus Kbcto the experimental bulk modulus Keand average atomic ring size,/ for×ncrease for x > 20 mol%.Our analysis also indicates that limited ring deformation took place and the main compression mechanism in this glass system was mainly ideal isotropic *** the other hand,optical band gap Eoptshowed small variation for x=0-20 mol%but decreased upon higher WO3content while refractive index n showed the opposite *** optical behavior is suggested to be related to the changes in cross link density and nBO concentration in the glass system.

关键词： Elastic moduli Optical absorption Raman spectrosco