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Flotation techniques to improve viability of Juniperus polycarpos seed lots

Journal of Forestry Research 2017年第2期28卷 231-239页

作者： abolfazl daneshvar Mulualem Tigabu Asaddollah Karimidoost Per Christer Odén Southern Swedish Forest Research Centre Swedish University of Agricultural SciencesP.O.Box 49SE-230 53 AlnarpSweden Department of Natural Resources Gonbad Kavoos UniversityShahid Fallahi StreetP.O.Box 163GonbadIran Agriculture and Natural Resources Research Center of Golestan Province Beheshti Ave.P.O.Box ***GorganIran

The germination of freshly collected Juniperus polycarpos（K. Koch） seeds is very low and attributed to the large proportion of nonviable seeds in the seed ***, the aim of this study was to improve seed lot quality by removing nonviable seeds using two flotation techniques： incubation-drying-separation（IDS） and modified specific gravity（MSG） separation. We examined different IDS conditions（the specific incubation time, subsequent drying time and sorting media） for effectively sorting out nonviable seeds; and tested the feasibility of modified SG separation, which involved soaking seeds in water for a certain period before sorting in different concentrations of sucrose solution. Viable seeds were expected to absorb and metabolically bind more water during soaking than dead seeds could, and hence be sorted effectively depending on the viscosity of the sucrose solution. The viability of the seeds that floated or sank was determined in a topographical tetrazolium chloride（TTC） test. For the IDS trial,7 days incubation followed by 9 h of drying and sedimentation in pure water or 200 g L-1sucrose solution identified, respectively, 75 and 82 % of the seeds as viable（sunken） seeds. For the MSG trail, 77 % viable seeds were recovered in the sunken fraction when seeds were soaked for 48 h then immediately sorted in 600 g L-1sucrose solution. In both cases, the loss of viable seeds in the discarded floating fraction was only 4 %. The results demonstrate that both IDS and MSG separation techniques substantially improved seed lot viability, but MSG separation is simple and needs no modern seed handling facility, and its efficacy relies on seed mass（due to the initial soaking） and the specific density and viscosity of the flotation medium.

关键词： viable viability sorting sucrose tetrazolium incubation subsequent viscosity proportion immediately

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Growth characteristics and reproductive output of dwarf mistletoeinfected Juniperus polycarpos in Iran

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Journal of Forestry Research 2014年第4期25卷 827-834页

作者： abolfazl daneshvar Mulualem Tigabu Asaddollah Karimidoost Mostafa Farhadi Per Christer Odén Swedish University of Agricultural Sciences Southern Swedish Forest Research Centre P.O Box 49 SE-230 53 Alnarp Sweden Department of Natural Resources Gonbad Kavous University Shahid Fallahi Street PO BOX: 163 Gonbad Iran Agriculture and Natural Resources Research Center of Golestan Province Beheshti Ave. PO Box *** Gorgan IRAN

Dwarf mistletoes are parasitic flowering plants that infect conifers, resulting in substantial loss of growth and mortality. Recently, forest managers in Iran are contemplating whether infection of Juniperus polycarpos C. Koch forests by dwarf mistletoe, Arceuthobium oxycedri （DC.） M. Bieb, influences tree vigor and contributes to insuffieient natural regeneration. The present study aimed at assessing the severity of infection and its impact on growth and reproductive output of./., polycar- pos. Infected and uninfected trees （n =20 each） were selected for assess- ment of diameter, height, crown area, and crown volume as well as quantity and quality of cones and seeds. The severity of infection of trees was determined by Hawksworth＇s 6-class dwarf mistletoe rating （DMR） system. The DMR system revealed that 40% of the infected sample trees were lightly infected （DMR =1-2） and 60% were moderately infected （DMR =3--4）. Growth characteristics did not differ significantly （p 〉 0.05） between infected and uninfected trees. However, moderate infec- tion affected the reproductive output of./. polycarpos by significantly （p 〈0.05） reducing the mean number of cones per unit area of the crown, increasing the number of damaged seeds, and reducing seed size and seedgermination capacity. We conclude that reproductive output of J.. poly- carpos is more sensitive than growth characters to moderate infection by juniper dwarf mistletoe, and this might partly account for poor natural regeneration.

关键词： conifers Greek juniper forest health parasitic plant seed size

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Pre-sowing treatment for breaking dormancy in Acer velutinum Boiss. seed lots

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Journal of Forestry Research 2013年第2期24卷 273-278页

作者： Mostafa Farhadi Mulualem Tigabu Alireza Ghasemi Arian Mehdi Sharifani abolfazl daneshvar Per Christer Oden Swedish University of Agricultural Sciences Southern Swedish Forest Research Centre Education Center of Jihad-Agriculture Gorgan University of Agricultural Sciences and Natural Resources Horticulture Department

Acer velutinum Boiss is a valuable tree species native to Iran, and its seeds possess physiological dormancy that hampers seedling production in the nursery for large-scale reforestation efforts. The aim of this study was to determine the optimal dormancy breaking treatments for A. velutinum seeds. We conducted a factorial experiment involving six seed lots collected along an elevation gradient from 300 to 1800 m at 300 m interval and four cold-moist stratification periods （0, 4, 8 and 16 weeks） at 4℃ and 70% relative humidity. The result shows that the germination of cold-moist stratified seeds was significantly （p 〈 0.0001） higher than the control for all seed lots. The highest germination capacity was recorded after 16 weeks of cold-moist stratification for all seed lots （68% 88% depending on the seed lot） except those collected from mid altitude sites （600 and 900 m） that germinated equally well （≥ 75%） after 4and 8-week of clod-moist stratification compared to the other seed lots. The mean germination time was significantly shorter （12 to 19 days, depending on the seed lot） for seeds stratified for 16 weeks than for untreated seeds. It can be concluded that：（1） cold-moist stratification for 16 weeks is the best pre-sowing treatment for breaking dormancy in A. velutinum seeds; and （2） seeds should be collected from mid altitude sites （600 and 900 m） to get more than 80% germination within 15 days, and these seed lots even required shorter cold-moist stratification period（eight weeks） than other seed lots.

关键词： cold-stratification altitude physiological dormancy velvet maple seed germination

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Physico-chemical characteristics and heavy metal concentrations of copper mine wastes in Zambia:implications for pollution risk and restoration

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Journal of Forestry Research 2020年第4期31卷 1283-1293页

作者： Mutale N.Chileshe Stephen Syampungani Emma Sandell Festin Mulualem Tigabu abolfazl daneshvar Per Christer Odén School of Natural Resources Copperbelt UniversityBox 21692KitweZambia Faculty of Forest Sciences Southern Swedish Forest Research CentreSwedish University of Agricultural SciencesBox 4923053 AlnarpLommaSweden Department of Biology Faculty of Basic Sciences and EngineeringGonbad Kavous UniversityShahid Fallahi StreetBasirat BlvdBox 163Gonbad-e-KavousGolestanIran

Soil characterization is a vital activity to develop appropriate and effective restoration protocols for mine wastelands while insights into the total content of heavy metals in the soil is an important step in estimating the hazards that the metals may pose to the vital roles of soil in the *** study addressed the following research questions:(1)To what extent do the physico-chemical characteristics vary between mine waste sediments and the nearby forest soil?(2)Are the concentrations of heavy metals high enough to be considered as toxic?and(3)Are heavy metals present in mine waste sediments potential sources of pollution?We hypothesized that the physicochemical characteristics of mine waste sediments are less favorably for plant establishment and growth while the concentrations of heavy metals are very high,thus restricting the success of revegetation of mine waste *** waste sediments were sampled following a diagonal transect across tailings dams,overburden dump sites and the local forest soil from the top layer(0-20 cm)using a closed *** were analyzed for arsenic,barium,lead,cadmium,cobalt,copper,chromium,nickel,vanadium,and zinc as well as for soil physico-chemical *** mine waste sediments were dominated by silt whilst the forest soil by sand particles,with significantly high bulk density in the *** the forest soil and overburden sediments were acidic than the alkaline tailings dam *** organic carbon and nitrogen contents were significantly low in mine wasteland substrates but the concentration of Ca and Mg were significantly higher in tailings dam substrate than the forest *** concentrations of available P,K and Na were similar across *** mean concentrations of heavy metals were significantly(pCo>Ba>Ni>As>Zn>Pb>Cr>V>Cd,and that on the overburd

关键词： Contamination factors Overburden material Phytostabilization Pollution load index Tailings dam

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Best compromising crashworthiness design of automotive S-rail using TOPSIS and modified NSGAⅡ

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Journal of Central South University 2015年第1期22卷 121-133页

作者： abolfazl Khalkhali School of Automotive Engineering Iran University of Science and Technology

In order to reduce both the weight of vehicles and the damage of occupants in a crash event simultaneously, it is necessary to perform a multi-objective optimal design of the automotive energy absorbing components. Modified non-dominated sorting genetic algorithm II(NSGA II) was used for multi-objective optimization of automotive S-rail considering absorbed energy(E), peak crushing force(Fmax) and mass of the structure(W) as three conflicting objective functions. In the multi-objective optimization problem(MOP), E and Fmax are defined by polynomial models extracted using the software GEvo M based on train and test data obtained from numerical simulation of quasi-static crushing of the S-rail using ABAQUS. Finally, the nearest to ideal point(NIP)method and technique for ordering preferences by similarity to ideal solution(TOPSIS) method are used to find the some trade-off optimum design points from all non-dominated optimum design points represented by the Pareto fronts. Results represent that the optimum design point obtained from TOPSIS method exhibits better trade-off in comparison with that of optimum design point obtained from NIP method.

关键词： automotive S-rail crashworthiness technique for ordering preferences by similarity to ideal solution(TOPSIS) method group method of data handling(GMDH) algorithm multi-objective optimization modified non-dominated sorting genetic algorithm(NSGA II) Pareto front

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Low-cost sensorless control of four-switch,brushless DC motor drive with direct back-EMF detection

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第2期10卷 201-208页

作者： abolfazl HALVAEI NIASAR abolfazl VAHEDI Hassan MOGHBELLI Department of Electrical Engineering Faculty of EngineeringUniversity of Kashan Center of Excellence for Power System Automation and Operation Iran University of Science and Technology Department of Science and Mathematics Texas A&M University at Qatar

We propose a position sensorless control scheme for a four-switch,three-phase brushless DC motor drive,based on the zero crossing point detection of phase back-EMF voltages using newly defined error functions(EFs). The commutation in-stants are 30° after detected zero crossing points of the EFs. Developed EFs have greater magnitude rather than phase or line voltages so that the sensorless control can work at a lower speed range. Moreover,EFs have smooth transitions around zero voltage level that reduces the commutation errors. EFs are derived from the filtered terminal voltages vao and vbo of two low-pass filters,which are used to eliminate high frequency noises for calculation of the average terminal voltages. The feasibility of the proposed sensorless control is demonstrated by simulation and experimental results.

关键词： Brushless DC motor Four-switch inverter Sensorless control Back-EMF voltage sensing DSP

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HBIR: Hypercube-Based Image Retrieval

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Journal of Computer Science & Technology 2012年第1期27卷 147-162页

作者： Hossein Ajorloo abolfazl Lakdashti Department of Computer Engineering Sharif University of Technology Tehran Iran University College of Rouzbahan Sari Iran

In this paper, we propose a mapping from low level feature space to the semantic space drawn by the users through relevance feedback to enhance the performance of current content based image retrieval （CBIR） systems. The proposed approach makes a rule base for its inference and configures it using the feedbacks gathered from users during the life cycle of the system. Each rule makes a hypercube （HC） in the feature space corresponding to a semantic concept in the semantic space. Both short and long term strategies are taken to improve the accuracy of the system in response to each feedback of the user and gradually bridge the semantic gap. A scoring paradigm is designed to determine the effective rules and suppress the inefficient ones. For improving the response time, an HC merging approach and, for reducing the conflicts, an HC splitting method is designed. Our experiments on a set of 11 000 images from the Corel database show that the proposed approach can better describe the semantic content of images for image retrieval with respect to some existing approaches reported recently in the literature. Moreover, our approach can be better trained and is not saturated in long time, i.e., any feedback improves the precision and recall of the system. Another strength of our method is its ability to address the dynamic nature of the image database such that it can follow the changes occurred instantaneously and permanently by adding and dropping images.

关键词： image retrieval relevance feedback rule base hypercube (HC)

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The Generalized-Fisher composite fading model for the next generation of mobile communication systems

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Digital Communications and Networks 2024年第5期10卷 1322-1331页

作者： Fereshteh Salimian Rizi abolfazl Falahati Department of Electrical Engineering Iran University of Science and Technology(IUST)

The new generation of communication systems is moving towards using a millimeter-wave *** the shadowing effects are undeniable in this type of propagation,the proposed Generalized Fisher(GF) distribution can be useful in modeling shadowed fading channels,considering the non-linearity and the multi-cluster nature of the diffusion *** introducing the model,its main statistics,including Probability Density Function(PDF),Cumulative Distribution Function(CDF),Moment Generating Function(MGF),and the distribution of the sum of an arbitrary number of independent and non-identically distributed(i.n.i.d.) random variables with GF distribution are ***,some wireless communication application criteria such as ergodic and outage capacities,are ***,considering the classic Wyner's wiretap model and passive eavesdropping scenario,specific security criteria,such as the probability of non-zero secrecy capacity and secrecy outage probability,are also *** expressions are measured in terms of either univariate or multivariate Fox's H-function.

关键词： Composite fading Ergodic capacity Generalized-Fisher distribution Secrecy analysis Sum of random variables

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Kinetic Study and NBO Analysis of the Dehydrogenation Mechanism of Five-membered Ring Heterocyclic 2,5-Dihydro-[furan, thiophene, selenophene]

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Chinese Journal of Chemistry 2011年第11期29卷 2249-2256页

作者： Shiroudi, abolfazl Zahedi, Ehsan Chemistry Department Shahrood Branch Islamic Azad University Shahrood Iran

The theoretical study of the dehydrogenation of 2,5-dihydro-[furan （1）, thiophene （2）, and selenophene （3）] was carried out using ab initio molecular orbital （MO） and density functional theory （DFT） methods at the B3LYP/6-311G＊＊//B3LYP/6-311G＊＊ and MP2/6-311G＊＊//B3LYP/6-311G＊＊ levels of theory. Among the used methods in this study, the obtained results show that B3LYP/6-311G＊＊ method is in good agreement with the available experimental values. Based on the optimized ground state geometries using B3LYP/6-311G＊＊ method, the natural bond orbital （NBO） analysis of donor-acceptor （bond-antibond） interactions revealed that the stabilization energies associated with the electronic delocalization from non-bonding lone-pair orbitals [LP（e）x3] to C＊C（1）- H（2） antibonding orbital, decrease from compounds 1 to 3. The LP（e）x3→σ＊c（1）-H（2） resonance energies for compounds 1--3 are 23.37, 16.05 and 12.46 kJ/mol, respectively. Also, the LP（e）xa→σ＊c（1）-H（2） delocalizations could fairly explain the decrease of occupancies of LP（e）x3 non-bonding orbitals in ring of compounds 1-3 （3 〉2 〉 1）. The electronic delocalization from LP（e）x3 non-bonding orbitals to σ＊c（1）-G（2） antibonding orbital increases the ground state structure stability, Therefore, the decrease of LP（e）x3→σ＊c（1）-H（2） delocalizations could fairly explain the kinetic of the dehydrogenation reactions of compounds 1-3 （kl〉k2〉k3）. Also, the donor-acceptor interactions, as obtained from NBO analysis, revealed that the πc（4）=c（7）→σ＊c（1）-H（2） resonance energies decrease from compounds 1 to 3. Further, the results showed that the energy gaps between πC（4）-C（7） bonding and σ＊c（1）-H（2） antibonding orbitals decrease from compounds 1 to 3. The results suggest also that in compounds 1--3, the hydrogen elimi- nations are controlled by LP（e）→σ＊ resonance energies. Analysis of bond order, natural bond orbital charges, bond indexes, synchronicity parameters, and IRC calculations indicate that these reactions are occurring through a con- ce

关键词： unimolecular reaction ab initio dehydrogenation density functional theory (DFT) intrinsic reaction coordinate (IRC) natural bond orbital (NBO)

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Assessment of groundwater potential using multi-criteria decision analysis and geoelectrical surveying

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Geo-Spatial Information Science 2022年第4期25卷 600-618页

作者： Marzieh Shabani Zohreh Masoumi abolfazl Rezaei Department of Earth Sciences Institute for Advanced Studies in Basic Sciences(IASBS)ZanjanIran Center for Research in Climate Change and Global Warming(CRCC) Institute for Advanced Studies in Basic Sciences(IASBS)ZanjanIran

A precise map of the dispersion of the groundwater potential across each watershed can help decision-makers to exert optimal water management in each *** this research,the potential of groundwater resources in both the Zanjanrood Catchment and the Tarom Region,located in the northwest of Iran,has been *** effective criteria including slope,land-use,drainage density,spring density,lithology,lineament density,and rainfall are *** were first weighted using the Analytical Hierarchical Process(AHP)method and then overlaid by the Technique for Order Preferences by Similarity to Ideal(TOPSIS)***,the spatial zoning map of groundwater potential was obtained in four categories.A sensitivity analysis was performed to determine the influence of each criterion on the obtained *** model was verified using both the spatial distribution of the high-discharged production wells and the geophysical-based geoelectric field *** results indicate that the high-discharged wells(>40 l/s)in both regions are dispersed predominantly in the very good zone and,in several cases,in the good ***,the results from the two-dimensional models of resistivity and induced polarization of geoelectrical field survey are inappropriate agreement with those from the TOPSIS ***,there is no suitable potential zone of groundwater in the surrounding highlands to be used in the future for drinking purposes since the highlands water supply is a strategic supply for *** strategies employed in this study,the results of GIS modeling,and the geoelectrical analysis can be considered for sustainable development of similar arid and semi-arid areas since groundwater is considered as the main supplier of water in such regions.

关键词： Spatial Information System(GIS) Remote Sensing(RS) groundwater potential TOPSIS geoelectrical field survey sustainable development

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