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Estimation of soil carbon pools in the forests of Khyber Pakhtunkhwa Province, Pakistan

Journal of Forestry Research 2020年第6期31卷 2313-2321页

作者： Anwar Ali Muhammad irfan ashraf Saeed Gulzar Muhammad Akmal Bilal Ahmad Pakistan Forest Institute Peshawar 25130Pakistan Department of Forestry and Range Management PMAS Arid Agriculture UniversityRawalpindi 46300Pakistan Institute of Soil Science PMAS Arid Agriculture UniversityRawalpindi 46300Pakistan Institute of Agriculture Sciences and Forestry University of SwatSwat 19130Pakistan

Forest soils have high carbon densities compared to other *** carbon sequestration is important to reduce CO 2 concentrations in the *** eff ective climate change mitigation strategy involves limiting the emissions of greenhouse gases from *** Pakhtunkhwa is the most forested province of Pakistan,hosting about one-third of the country’s 4.5×106 ha forest *** organic carbon in the province’s forests was estimated through a fi eld-based study carried out during 2014–17 covering the whole *** was collected from 373 sample plots laid out in diff erent forest types using a stratifi ed cluster sampling *** total quantity of soil organic carbon was estimated at 59.4×106 t with an average of 52.4±5.3 t/*** 69%of the total soil carbon is present in temperate *** broad-leaved and subtropical pine forests constitute 11.4%and 8.8%of the soil carbon stock ***,subalpine and oak forests have respective shares of 5.1%and 5.7%in the soil carbon *** lowest carbon stock(0.1%)was found in dry-tropical thorn *** highest soil carbon density was found in subalpine forests(69.5±7.2 t/ha)followed by moist temperate forests(68.5±6.7 t/ha)and dry temperate forests(60.7±6.5 t/ha).Oak forests have carbon density of 43.4±7.1 t/*** pine,subtropical broad-leaved and dry tropical thorn forests have soil carbon densities of 36.3±3.7,32.8±6.2 and 31.5±3.5 t/ha,*** forests of the Khyber Pakhtunkhwa province have substantial amounts of soil carbon which must be conserved for climate change mitigation and maintenance of sound forest health.

关键词： Soil carbon Carbon sequestration Climate change Carbon sink Forests Khyber Pakhtunkhwa

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Evaluation of state and community/private forests in Punjab, Pakistan using geospatial data and related techniques

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Forest Ecosystems 2015年第2期2卷 155-167页

作者： Naeem Shahzad Urooj Saeed Hammad Gilani Sajid Rashid Ahmad irfan ashraf Syed Muhammad Irteza World Wide Fund for Nature (WWF) Institute of Geology University of the Punjab International Centre for Integrated Mountain Development (ICIMOD) Department of Land Surveying and Geo-Informatics Hong Kong Polytechnic University

Background： Forests are fundamental in maintaining water supplies, providing economic goods, mitigating climate change, and maintaining biodiversity, thus providing many of the world＇s poorest with income, food and medicine. Too often, forested lands are treated as ＂wastelands＂ or ＂free＂ and are easily cleared for agricultural and infrastructure expansion. Methods： In this paper, the sustainability of two forest ecosystems （state and community/private owned） was evaluated using SPOT-5 satellite images of 2005 and 2011. This study was conducted in a sub-watershed area covering 468 km2, of which 201 km2 is managed by the state and 267 km2 by community/private ownership in the Murree Galliat region of Punjab Province of Pakistan. A participatory approach was adopted for the delineation and demarcation of forest boundaries. The Geographic Object-Based Image Analysis （GEOBIA） technique was used for identification and mapping of ten Land Cover （LC） features. Results： The results show that between the years 2005 to 2011, a total of 55 km2 （24 km2 in state-owned forest and 31 km2 in community/private forest） was converted from forest to non-forest. The conclusion is that conservation is more effective in state-owned forests than in the community/private forests. Conclusions： These findings may help to mobilize community awareness and identify effective initiatives for improved management of community/private forest land for other regions of Pakistan.

关键词： Forest management SPOT-5 satellite images State and community/private owned forests Murree Galliat Pakistan

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Exploring the potential of Sentinel-2A satellite data for aboveground biomass estimation in fragmented Himalayan subtropical pine forest

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Journal of Mountain Science 2020年第12期17卷 2880-2896页

作者： Mobushir Riaz KHANI Iftikhar Ahmad KHAN Muhammad Hasan Ali BAIG LIU Zheng-jia Muhammad irfan ashraf School of Environmental Science Charles Sturt UniversityAlburyNSW 2640Australia Institute of Geo-information&Earth Observation Arid Agriculture University RawalpindiPakistan&(ii)Department of ForestAzad Jammu&Kashmir Muzaffarabad-i3100Pakistan Institute of Geo-information&Earth Observation(IGEO) PMAS Arid Agriculture University Rawalpindi 46300Pakistan Institute of Geographic Sciences and Natural Resources Research Chinese Academy of SciencesBeijing 100101China Department of Forestry&Range Management PMAS Arid Agriculture University Rawalpindi 46300Pakistan

The Sentinel-2 A satellite having embedded advantage of red edge spectral bands offers multispectral imageries with improved spatial,spectral and temporal resolutions as compared to the other contemporary satellites providing medium resolution *** study was aimed at exploring the potential of Sentinel-2 A imagery to estimate Above Ground Biomass(AGB) of Subtropical Pine Forest in Pakistan administered *** developed an AGB predictive model using field inventory and Sentinel 2 A based spectral and textural parameters along with topographic features derived from ALOS Digital Elevation Model(DEM).Field inventory data was collected from 108 randomly distributed plots(0.1 ha each) across the study *** stepwise linear regression method was employed to investigate the potential relationship between field data and corresponding satellite *** and carbon mapping of the study area was carried out through established AGB estimation model with R(o.86),R2(0.74),adjusted R2(0.72) and RMSE value of 33 t/*** results showed that first order textures(mean,standard deviation and variance) significantly contributed in AGB predictive modeling while only one spectral band ratio made contribution from spectral *** study leads to the conclusion that Sentinel-2 A optical data is a potential source for AGB estimation in subtropical pine forest of the area of interest with added benefit of its free of cost availability,higher quality data and long-term continuity that can be utilized for biomass carbon distribution mapping in the resource constraint study area for sustainable forest management.

关键词： Field inventory Forest Biomass Sentinel 2A AGB Modelling Spectral features Textures

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Modular Multilevel Converter with Wireless Magnetic Power Decoupling for Three-phase MV Adjustable-speed Drives

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CSEE Journal of Power and Energy Systems 2022年第5期8卷 1497-1507页

作者： Mohamed Atef Tawfik Mohammad Sameer irfan ashraf Ahmed Joung-Hu Park Department of Electrical Engineering Soongsil UniversitySeoul 156-743South Korea

In this paper,we propose a modular multilevel converter(MMC)with a wireless magnetic power decoupling approach suitable for medium-voltage high-power variable-speed machine *** proposed power decoupling approach is independent of the operating frequency,which solves the issue of wide fluctuations of low-frequency voltage ripple components in submodule(SM)capacitors,especially at low-speed operations without using any ripple power *** wireless magnetic elements reduces the amount of high-voltage insulation between the transformer windings,resulting in a significant reduction in the overall size of the *** basic idea of our proposed approach is to magnetically couple the instantaneous three-phase ripple power of each of the three adjacent-arm *** proposed MMC is free from low-frequency capacitors,resulting in enhanced system reliability,volume,and *** operation principles of the proposed MMC are explained,and a control design is *** performance of the proposed scheme was verified via simulation and experimental tests.

关键词： Modular multilevel converter power decoupling submodule capacitor voltage ripple variable-speed drives wireless high-frequency transformer

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Miniaturized Argon Plasma: Neutral Gas Characteristics in Dielectric Barrier Discharge

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Plasma Science and Technology 2015年第10期17卷 853-861页

作者： ashraf FARAHAT Department of Prep Year Physics College of Applied and Supporting StudiesKing Fahd University of Petroleum and Minerals(KFUPM) Department of Physics Faculty of Science Moharam Beek Alexandria University

Plasma-neutral gas dynamics is computationally investigated in a miniaturized mi- crothruster~ that encloses Ar and contains dielectric material sandwiched between two metal plates using a two-dimensional plasma mode. Spatial and temporal plasma properties are investigated by solving the Poisson equation with the conservation equations of charged and excited neutral plasma species using the COMSOL Multiphysics 4.2b. The microthruster property is found to depend on the secondary electron emission coefficient. The electrohydrodynamic force （EHD） is calculated and found to be significant in the sheath area near the dielectric layer and is found to affect gas flow dynamics including the Ar excimer formation and density. The effects of pressure and secondary emission coefficient are discussed. The plasma characteristics are affected by small changes in the secondary electron emission coefficient, which could result from the dielec- tric erosion and aging, and is found to affect the electrohydrodynamic force produced when the microthruster is used to produce thrust for a small spacecraft.

关键词： plasma modeling plasma species dielectric barrier discharge

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A review of recent advancements in finite element formulation for sandwich plates

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Chinese Journal of Aeronautics 2019年第4期32卷 785-798页

作者： Shehzaib irfan Faisal SIDDIQUI Aerospace Engineering Department College of Aeronautical Engineering National University of Sciences and TechnologyRisalpur

Use of composite structures is exponentially growing in different fields due to their higher strength-to-weight ratio. This application trend requires that accurate theoretical explanations and their finite element models be developed for analyzing sandwich plates before finalizing the designs. This paper reviews the recent research trends of finite element formulations developed for analyzing sandwich plates. This paper reviews the finite element models developed after the year 2000. Initially, the finite element formulations based on first order shear deformation theory, higher order shear deformation theories, mixed solid-shell elements, zig-zag theories and global–local theories are presented. Then, some finite element formulations developed to analyze a very new class of structures called piezoelectric structures are presented. At the end, some formulations to analyze a very critical phenomenon called buckling are presented.

关键词： Buckling Finite element FSDT HSDT Laminated composites Piezoelectric Sandwich plates Zig-zag theory

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Hydraulic jump basins with wedge-shaped baffles

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2012年第7期13卷 519-525页

作者： ashraf Fathy ELLAYN Institute of Port Coastal and Offshore Engineering Zhejiang University

This laboratory study deals with the hydraulic jump properties for an artificially roughened bed with wedge-shaped baffle blocks. The experiments were conducted for both smooth and rough beds with a Froude number in the range of 3.06≤F1≤10.95 and a relative bed roughness ranging 0.22≤KR≤1.4. The data from this study were compared with those of rectangular baffle blocks. New experimental formulae were developed for determining the sequent depth ratio and the hydraulic jump length in terms of the inflow Froude number and relative bed roughness. Bélanger's jump equation of a rectangular channel was extended to account for the implications of the bed shear stress coefficient attributable to channel bed roughness. It was found that, in comparison with the smooth bed, the wedge-shaped bed roughness reduced the sequent depth of the hydraulic jump by approximately 16.5% to 30% and the hydraulic jump length by approximately 30% to 53%.

关键词： Energy dissipater Hydraulic jump Stilling basins Wedge-shaped bed roughness

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Arabic Bank Check Processing: State of the Art

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Journal of Computer Science & Technology 2013年第2期28卷 285-299页

作者： irfan Ahmad Sabri A.Mahmoud Information and Computer Science Department King Fahd University of Petroleum & Minerals

In this paper, we present a general model for Arabic bank check processing indicating the major phases of a check processing system. We then survey the available databases for Arabic bank check processing research. The state of the art in the different phases of Arabic bank check processing is surveyed （i.e., pre-processing, check analysis and segmentation, features extraction, and legal and courtesy amounts recognition）. The open issues for future research are stated and areas that need improvements are presented. To the best of our knowledge, it is the first survey of Arabic bank check processing.

关键词： handwriting analysis document analysis text processing feature evaluation and selection pattern analysis

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MHD stagnation point flow of a micropolar fluid towards a heated surface

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Applied Mathematics and Mechanics(English Edition) 2011年第1期32卷 45-54页

作者： M.ashraf M.M.ashraf Centre for Advanced Studies in Pure and Applied Mathematics Bahauddin Zakariya University

The problem of two dimensional stagnation point flow of an electrically conducting micropolar fluid impinging normally on a heated surface in the presence of a uniform transverse magnetic field is analyzed. The governing continuity, momentum, angular momentum, and heat equations together with the associated boundary conditions are reduced to dimensionless form using suitable similarity transformations. The reduced self similar non-linear equations are then solved numerically by an algorithm based on the finite difference discretization. The results are further refined by Richardson＇s extrapolation. The effects of the magnetic parameter, the micropolar parameters, and the Prandtl number on the flow and temperature fields are predicted in tabular and graphical forms to show the important features of the solution. The study shows that the velocity and thermal boundary layers become thinner as the magnetic parameter is increased. The micropolar fluids display more reduction in shear stress as well as heat transfer rate than that exhibited by Newtonian fluids, which is beneficial in the flow and thermal control of polymeric processing.

关键词： magnetohydrodynamics (MHD) stagnation flow micropolar fluids finitedifferences similarity transformations boundary layer

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Employing adaptive fuzzy computing for RCP intelligent control and fault diagnosis

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Nuclear Science and Techniques 2023年第9期34卷 82-93页

作者： ashraf Aboshosha Hisham A.Hamad Rad.Eng.Department NCRRTEgyptian Atomic Energy Authority(EAEA)CairoEgypt Electronics Technology Department Faculty of Technology and EducationHelwan UniversityCairoEgypt

Loss of coolant accident(LOCA),loss of fluid accident(LOFA),and loss of vacuum accident(LOVA)are the most severe accidents that can occur in nuclear power reactors(NPRs).These accidents occur when the reactor loses its cooling media,leading to uncontrolled chain reactions akin to a nuclear *** article is focused on exploring methods to prevent such accidents and ensure that the reactor cooling system remains fully *** reactor coolant pump(RCP)has a pivotal role in facilitating heat exchange between the primary cycle,which is connected to the reactor core,and the secondary cycle associated with the steam ***,the RCP is integral to preventing catastrophic events such as LOCA,LOFA,and LOVA *** this study,we discuss the most critical aspects related to the RCP,specifically focusing on RCP control and RCP fault *** AI-based adaptive fuzzy method is used to regulate the RCP’s speed and torque,whereas the neural fault diagnosis system(NFDS)is implemented for alarm signaling and fault diagnosis in nuclear *** address the limitations of linguistic and statistical intelligence approaches,an integration of the statistical approach with fuzzy logic has been *** integrated system leverages the strengths of both *** fuzzy control was applied to the VVER 1200 NPR-RCP induction motor,and the NFDS was implemented on the Kori-2 NPR-RCP.

关键词： Nuclear power plant(NPP) Reactor coolant pump Fault diagnosis Reactor passive safety Neural network Adaptive fuzzy

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