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Forest structure and woody plant species composition after a wildfire in beech forests in the north of Iran

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Journal of Forestry Research 2013年第2期24卷 255-262页

作者： Mohammad Naghi adel.Hassan Pourbabaei Ali Omidi Daniel C Dey Facultad de Department of Forestry Natural Resources Faculty University of Guilan Department of Forestry Natural Resources Office USDA Forest Service Northern Research Station 202 Natural Resources Building

Beech （Fagus orientalis Lipsky） forest covers about 565,000 ha of land in Guilan province, north of Iran and forms a major carbon pool. It is an important economic, soil protection and recreation resource. We studied long-term effects of fire on the structure and composition 37 years after fire occurrence in these forests. To do this research, we selected 85 ha burned and 85 ha unburned beech forests）. The results indicated that the fire had not changed the overall uneven-aged structure, but it changed forest composition from pure stands to mixed stands that now include species such as Carpinus betulus, Acer cappadocicum and Alnus subcordata. The density of trees and regeneration was significantly increased, while the density of shrubs significantly decreased. The main reasons for increased tree regeneration were attributed to （1） reduction of litter depth, and （2） increase in available light from opening of the canopy and reduction in shrub competition. It is apparent that the forest is on a path to return to its natural state before the fire after 37 years.

关键词： fire structure composition regeneration beech forest Guilan Province

Multi-Scale Network with Integrated Attention Unit for Crowd Counting

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Computers, Materials & Continua 2022年第11期73卷 3879-3903页

作者： adel.Hafeezallah Ahlam Al-Dhamari Syed Abd Rahman Abu-Bakar Department of Electrical Engineering Taibah UniversityMadinahSaudi Arabia Department of Electronics and Computer Engineering School of Electrical EngineeringFaculty of EngineeringUniversiti Teknologi Malaysia81310JohorMalaysia Department of Computer Engineering Hodeidah UniversityHodeidahYemen

Estimating the crowd count and density of highly dense scenes witnessed in Muslim gatherings at religious sites in Makkah and Madinah is critical for developing control strategies and organizing such a large ***,since the crowd images in this case can range from low density to high density,detection-based approaches are hard to apply for crowd ***,deep learning-based regression has become the prominent approach for crowd counting problems,where a density-map is estimated,and its integral is further computed to acquire the final count *** this paper,we put forward a novel multi-scale network(named 2U-Net)for crowd counting in sparse and dense *** proposed framework,which employs the U-Net architecture,is straightforward to implement,computationally efficient,and has single-step *** layers are used to retrieve the pooling layers’erased information and learn hierarchically pixelwise spatial *** helps in obtaining feature values,retaining spatial locations,and maximizing data integrity to avoid data *** addition,a modified attention unit is introduced and integrated into the proposed 2UNet model to focus on specific crowd *** proposed model concentrates on balancing the number of model parameters,model size,computational cost,and counting accuracy compared with other works,which may involve acquiring one criterion at the expense of other *** on five challenging datasets for density estimation and crowd counting have shown that the proposed model is very effective and outperforms comparable mainstream ***,it counts very well in both sparse and congested crowd *** 2U-Net model has the lowest MAE in both parts(Part A and Part B)of the ShanghaiTech,UCSD,and Mall benchmarks,with 63.3,7.4,1.5,and 1.6,***,it obtains the lowest MSE in the ShanghaiTech-Part B,UCSD,and Mall benchmarks with 12.0,1.9,and 2.1,respectively.

关键词： Computer vision crowd analysis crowd counting U-Net max-pooling index unpooling attention units

Numerical Simulation of Double Diffusive Mixed Convection in a Horizontal Annulus with Finned Inner Cylinder

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Fluid Dynamics & Materials Processing 2019年第2期15卷 153-169页

作者： Cherfi Ryad Sadaoui Djamel Sahi adel.Mouloud Smail Laboratoire de Mécanique Matériaux et Energétique(L2ME)Facultéde TechnologieUniversitéde Bejaia06000BejaiaAlgérie

The present work relates to a numerical investigation of double diffusive mixed convection around a horizontal annulus with a finned inner *** solutal and thermal buoyancy forces are sustained by maintaining the inner and outer cylinders at uniform temperatures and *** effects are also considered,with the Boussinesq *** forced convection effect is induced by the outer cylinder rotating with an angular velocity(ω)in an anti-clockwise *** studies are made for various combinations of dimensionless numbers;buoyancy ratio number(N),Lewis number(Le),Richardson number(Ri)and Grashof number(Gr).The isotherms,isoconcentrations and streamlines as well as both average and local Nusselt and Sherwood numbers were studied.A finite volume scheme is adopted to solve the transport equations for continuity,momentum,energy and mass *** results indicate that the use of fins on the inner cylinder with outer cylinder rotation,significantly improves the heat and mass transfer in the annulus.

关键词： Finned inner cylinder double diffusive flow heat and mass transfer rotating annulus mixed convection numerical simulation

Photo-Induced Spin Dynamics in Nanoelectronic Devices

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Chinese Physics Letters 2012年第10期29卷 248-252页

作者： Mina D.Asham Walid A.Zein adel.H.Phillips Faculty of Engineering Benha UniversityBenhaEgypt Faculty of Engineering Ain-Shams UniversityCairoEgypt

The present research is devoted to the investigation of electron spin transmission through a nanoelectronic *** device is modeled as nonmagnetic semiconductor quantum dot coupled to two diluted magnetic semiconductor *** spin transport characteristics through such a device are investigated under the effect of an ac-field of a wide range of *** present result shows a periodic oscillation of the conductance for both the cases of parallel and antiparallel spin *** oscillations are due to *** for spin polarization and giant magneto-resistance show the coherency *** present research might be useful for developing single spin-based quantum bits(qubits)required for quantum information processing and quantum spin-telecommunication.

关键词： property quantum electronic

Flocking control of a fleet of unmanned aerial vehicles

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Control Theory and Technology 2018年第2期16卷 82-92页

作者： adel.BELKADI Zhixiang LIU Laurent CIARLETTA Youmin ZHANG Didier THEILLIOL CRAN University of Lorraine Nancy France Department of Mechanical Industrial and Aerospace Engineering Concordia University Montreal Canada Lorraine Research Laboratory in Computer Science and its Applications (LORIA) University of Lorraine Nancy France

Current applications using single unmanned vehicle have been gradually extended to multiple ones due to their increased efficiency in mission accomplishment, expanded coverage areas and ranges, as well as enhanced system reliability. This paper presents a flocking control method with application to a fleet of unmanned quadrotor helicopters （UQHs）. Three critical characteristics of formation keeping, collision avoidance, and velocity matching have been taken into account in the algorithm development to make it capable of accomplishing the desired objectives （like forest/pipeline surveillance） by safely and efficiently operating a group of UQHs. To achieve these, three layered system design philosophy is considered in this study. The first layer is the flocking controller which is designed based on the kinematics of UQH. The modified Cucker and Smale model is used for guaranteeing the convergence of UQHs to flocking, while a repelling force between each two UQHs is also added for ensuring a specified safety distance. The second layer is the motion controller which is devised based on the kinetics of UQH by employing the augmented state-feedback control approach to greatly minimize the steady-state error. The last layer is the UQH system along with its actuators. Two primary contributions have been made in this work： first, different from most of the existing works conducted on agents with double integrator dynamics, a new flocking control algorithm has been designed and implemented on a group of UQHs with nonlinear dynamics. Furthermore, the constraint of fixed neighbouring distance in formation has been relaxed expecting to significantly reduce the complexity caused by the increase of agents number and provide more flexibility to the formation control. Extensive numerical simulations on a group of UQH nonlinear models have been carried out to verify the effectiveness of the proposed method.

关键词： Flocking unmanned aerial vehicles unmanned quadrotor helicopters Cucker and Smale formation control

Robust design and analysis for opto-mechanical two array laser warning system

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Defence Technology(防务技术) 2023年第9期27卷 46-52页

作者： Mazhar Tayel Mohamed Shehata Mohamed Mabrouk Abdlarhman adel.Mohamed Shady Shokry Mostafa Alshershby Faculty of Engineering Alexandria UniversityAlexandriaEgypt Egyptian Air Defense Collage AlexandriaEgypt Laser and Optoelectronics Department Technical Research CenterEgypt

In the past three decades,laser warning systems(LWS)have emerged in great importance,as the development of laser-guided weapons,such as airborne Hellfire missiles,has increased,posing an imminent threat to vital areas and *** laser warning station(LWS)can detect,classify,identify,and give alarm from laser threat at a very short time with high ***,the designers of this system must take into account the detectability and field of view to cover the area to be *** main contribution in this research is an analytical design of LWS that consists of 24 detector elements,distributed in two arrays(2×12)***,calculating the best distance between the detectors according to the laser beam spot *** addition,enhancement laser warring sensor detection capability and detection performance FOV between the detectors to increase coverage area up to 360°.Moreover,decreasing dead zone area between the laser detectors *** calculations and illustrations made to reach the best systematic design.

关键词： LWS Field of view Detector elements

Islands of stability and quasi-magic numbers for super- and ultra-heavy nuclei

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Chinese Physics C 2016年第12期40卷 69-90页

作者： M.Ismail A.Y.Ellithi A.adel.Hisham Anwer Physics Department Faculty of Science Cairo University Physics Department College of Science Majmaah University Physics Department German University in Cairo

In the framework of Strutinsky＇s approach, we calculated the shell and the residual pairing correction energies for 5569 even-even nuclei in the range 72 ≤ Z ≤ 282 and 96≤N ≤ 540. Quasi-magic numbers and deformed islands of stability that reside in a range defined by Green＇s formula and the two-neutrons drip line are introduced. We present 36 quasi-magic proton and 53 quasi-magic neutron magic numbers that contribute to the formation of 133 deformed islands of stability along the N-Z space. The quasi-magic proton and neutron magic numbers volatile as the mass number increases and other magic numbers take over. Consequently, the deformed islands of stability fail to exhibit a pattern along the search space covered.

关键词： deformed nuclei islands of stability magic numbers

Stabilization of chromium(Ⅵ) by hydroxysulfate green rust in chromium(Ⅵ)-contaminated soils

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Pedosphere 2021年第4期31卷 645-657页

作者： Leila ALIDOKHT Shahin OUSTAN Alireza KHATAEE Mohammad R.NEYSHABURI adel.REYHANITABAR Faculty of Agriculture Department of Soil ScienceUniversity of TabrizTabriz 51666-16471(Iran) Research Laboratory of Advanced Water and Wastewater Treatment Processes Department of Applied ChemistryFaculty of ChemistryUniversity of TabrizTabriz 51666-16471(Iran) Department of Environmental Engineering Gebze Technical UniversityGebze 41400(Turkey)

Chromium(Cr)-contaminated soils pose a great environmental risk, with high solubility and persistent leaching of Cr(Ⅵ). In this study, hydroxysulfate green rust(GR_(SO4)), with the general formula Fe(Ⅱ)_(4) Fe(Ⅲ)_(2)(OH)_(12) SO_(4)·8 H_(2) O, was evaluated for its efficiency in Cr(Ⅵ) stabilization via Cr(Ⅵ) reduction to Cr(Ⅲ) in four representative Cr(Ⅵ)-spiked soils. The initial concentrations of phosphate buffer-extractable Cr(Ⅵ)(Cr(Ⅵ)b) in soils 1, 2, 3, and 4 were 382.4, 575.9, 551.3, and 483.7 mg kg^(-1), respectively. Reduction of Cr(Ⅵ) to Cr(Ⅲ) by structural Fe(Ⅱ)(Fe(Ⅱ)s) in GR_(SO4) in all studied soils was fast,wherein the application of GR_(SO4) markedly decreased the amount of Cr(Ⅵ)bat the Cr(Ⅵ)b/Fe(Ⅱ)s stoichiometric mole ratio of 0.33. The kinetics of Cr(Ⅵ)reduction by GR_(SO4) could not be determined as this reaction coincided with the release of Cr(Ⅵ) from soil during the experiment. The concentration of Cr(Ⅵ)bdecreased, as the Cr(Ⅵ)b/Fe(Ⅱ)s ratio decreased from 0.46 to 0.20, generally to below 10 mg kg^(-1). Back-transformation of the generated Cr(Ⅲ)was examined in the presence of manganese oxide birnessite at the birnessite/initial Cr(Ⅲ) mole ratio of 4.5. The results of batch tests showed that only 5.2% of the initial Cr(Ⅲ) was converted to Cr(Ⅵ) after two months, while under field capacity moisture conditions, less than 0.05% of the initial Cr(Ⅲ) was oxidized to Cr(Ⅵ) after six months. The results illustrated that remediation of Cr(Ⅵ)-contaminated soils would be fast, successful, and irreversible with an appropriate quantity of fresh GR_(SO_(4)).

关键词： batch system birnessite Cr(Ⅲ)oxidation layered double hydroxide reduction soil remediation

Robust correlation to predict dew point pressure of gas condensate reservoirs

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Petroleum 2017年第3期3卷 340-347页

作者： Mohammad Ali Ahmadi adel.Elsharkawy Department of Petroleum Engineering Ahwaz Faculty of Petroleum EngineeringPetroleum University of TechnologyAhwazIran Department of Petroleum Engineering College of Engineering&PetroleumKuwait UniversityKuwait

When the bottom-hole flowing pressure in a gas condensate reservoir drops below the dew point pressure,liquid starts to build up around the well bore resulting in gas productivity *** this reason it is important to be able to accurately either measure or estimate the dew point *** condensate formed in the reservoir will not flow until its saturation reaches the critical saturation and in many cases it might not be entirely *** order to maximize gas production and condensate recovery,the reservoir pressure must be maintained close to the dew point *** attempts have been made to predict the dew point pressure in case the gas sample becomes unavailable or measured value is ***,most of these attempts have minor success rates and are based on limited *** this paper we present a robust,cheap,and easy model for predicting the dew point pressure for gas condensate *** new model is an intelligent based model called“Gene Expression Programming”that is carried out to generate a precise and accurate correlation to estimate the dew point pressure in condensate gas *** new model has been trained and tested using a large data bank collected for the *** of the suggested correlation has been compared to published *** validity of this model has also been compared to experimental data and other published correlations.

关键词： Dew point pressure Gene Expression Programming Condensate gas Modeling