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Evolutional Characteristics of Debris Flow in the Siwalik Hills of Nepal

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International Journal of Geosciences 2019年第12期10卷 1049-1067页

作者： bharat prasad bhandari Subodh Dhakal Central Department of Environment Science Tribhuvan University Kirtipur Nepal Department of Geology Tri-Chandra Multiple Campus Tribhuvan University Kathmandu Nepal

As a youngest Mountain of the world, Siwalik region of Nepal is facing several mass movements like landslide and debris flow in monsoon period every year. Debris flow is very common in the steep slope of weak and fragile sedimentary rocks. This paper used remote sensing data and GIS to evaluate evolutional characteristics of debris flow hazard in the Siwalik hill of Babai watershed based on the geological, topographical and hydrological factors. All together 101 debris flow polygons were made by using Google Earth and by field verification. Digital Elevation Model (DEM) was used to analyze debris flow distribution and topographical features. Lithostratigraphy was studied to evaluate geological characters and rainfall data was used to evaluate hydrological character. Average slope for debris flow evolution in Lower, Middle and Upper Siwalik is 34°, 50° and 30° respectively. The average 24 hours rainfall to occur debris flow is found 160.67 mm. The area and length of debris flow channel are significantly different in three geological formations. The temporal distribution of debris flow from 2001 to 2018 shows that the trend of debris flow generation is higher in Middle Siwalik rocks with slope greater than 30°. Three major sources of debris flows were evaluated namely slide induced debris flow, fall induced debris flow and erosion induced debris flow where the slide induced debris flow is predominant. This study can be better source to understand the general mechanism of debris flow generation to the policy makers for reducing the future impact of debris flow in the overall Siwalik zone of Nepal.

关键词： Debris Flow GIS Siwaliks Topography

GIS-Based Frequency Ratio Method for Identification of Potential Landslide Susceptible Area in the Siwalik Zone of Chatara-Barahakshetra Section, Nepal

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Open Journal of Geology 2019年第12期9卷 873-896页

作者： Dinesh Thapa bharat prasad bhandari Golden Gate International College Tribhuvan University Kathmandu Nepal Central Department of Environmental Science Tribhuvan University Kirtipur Nepal

The hilly regions of Nepal are potential for land sliding in rainy season. Lying between two major thrusts: Main Frontal Thrust (MFT) and Main Boundary Thrust (MBT), the rocks of Siwalik zone are very weak and fragile. Shallow and deep landslides are very common in the Siwalik zone during heavy and continuous rainfall. The landslide in the busy road and agglomerate settlements are destroying the life and properties every year in rainy season. This study aims to develop a landslide susceptibility map of Chatara-Barahakshetra area, Siwalik zones of eastern Nepal by the means of frequency ratio model. The paper utilized the remote sensing and GIS to develop a landslide susceptibility map. Total of 382 landslide polygons were mapped from Google earth and by field verification. The validation results showed that the success rate curve with 72.55 percentage of the area lying under the curve and the prediction rate curve with 71.73 percentage of the area lying under the curve indicating that prediction ability of the Frequency Ratio model. These landslide susceptibility maps can be used as a planning tool by prioritizing areas for controlling the landslide effects. More than 71% success rate indicate that frequency ratio model is suitable model for the landslide susceptibility in the study area.

关键词： Factor Map Landslide Inventory Frequency Ratio Susceptibility Validation

Impact of a Magnetic Dipole on Heat Transfer in Non-Conducting Magnetic Fluid Flow over a Stretching Cylinder

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Fluid Dynamics & Materials Processing 2024年第3期20卷 475-486页

作者： Anupam bhandari Department of Mathematics School of EngineeringUniversity of Petroleum&Energy Studies(UPES)Energy Acres BuildingBidholi DehradunUttarakhand248007India

The thermal behavior of an electrically non-conducting magnetic liquid flowing over a stretching cylinder under the influence of a magnetic dipole is *** governing nonlinear differential equations are solved numerically using a finite element approach,which is properly validated through comparison with earlier results available in the *** results for the velocity and temperature fields are provided for different values of the Reynolds number,ferromagnetic response number,Prandtl number,and viscous dissipation *** influence of some physical parameters on skin friction and heat transfer on the walls of the cylinder is also *** applicability of this research to heat control in electronic devices is discussed to a certain extent.

关键词： Ferrofluid stretching cylinder finite element method heat transfer magnetic dipole

Design of Power System Stabilizer for DFIG-based Wind Energy Integrated Power Systems Under Combined Influence of PLL and Virtual Inertia Controller

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Journal of Modern Power Systems and Clean Energy 2024年第2期12卷 524-534页

作者： Balakrushna Sahu Bibhu prasad Padhy Department of Electrical Engineering Indian Institute of Technology RoparPunjab140001India

Wind energy systems (WESs) based on doubly-fed induction generators (DFIGs) have enormous potential for meeting the future demands related to clean energy. Due to the low inertia and intermittency of power injection, a WES is equipped with a virtual inertial controller (VIC) to support the system during a frequency deviation event. The frequency deviation measured by a phase locked loop (PLL) installed on a point of common coupling (PCC) bus is the input signal to the VIC. However, a VIC with an improper inertial gain could deteriorate the damping of the power system, which may lead to instability. To address this issue, a mathematical formulation for calculating the synchronizing and damping torque coefficients of a WES-integrated single-machine infinite bus (SMIB) system while considering PLL and VIC dynamics is proposed in this paper. In addition, a power system stabilizer (PSS) is designed for wind energy integrated power systems to enhance electromechanical oscillation damping. A small-signal stability assessment is performed using the infinite bus connected to a synchronous generator of higher-order dynamics integrated with a VIC-equipped WES. Finally, the performance and robustness of the proposed PSS is demonstrated through time-domain simulation in SMIB and nine-bus test systems integrated with WES under several case studies.

关键词： Doubly-fed induction generator(DFIG) virtual inertia controller(VIC) phase locked loop(PLL) small-signal analysis synchronizing/damping torque synchronous generator power system stabilizer(PSS)

评估农林业适应气候变化的潜力:尼泊尔拉姆琼案例研究

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Journal of Resources and Ecology 2024年第2期15卷 280-292页

作者： JOSHI Rajeev TAMANG Gyanu Maya bhandari Prativa SHARMA bharat JOSHI Dikshya BHUSAL Shushma 尼泊尔农林大学林学院自然资源管理学院尼泊尔卡塔里56310 特里布万大学林业研究所(博卡拉校区) 尼泊尔博卡拉33700 森林和土壤保护部森林部门办公室尼泊尔久姆拉21200 森林研究所印度德拉敦248001 远西大学农学院尼泊尔提卡波10901

农林系统具有多种效益,包括通过使用肥用树种来提高土壤质量,通过树冠改善小气候,以及生产薪柴和其他医药产品等森林产品以提高经济效益。农林复合经营有助于更好的土地管理、生计多样化和提高土地生产力。然而,政策制定者和其他利益相... 详细信息

农林系统具有多种效益,包括通过使用肥用树种来提高土壤质量,通过树冠改善小气候,以及生产薪柴和其他医药产品等森林产品以提高经济效益。农林复合经营有助于更好的土地管理、生计多样化和提高土地生产力。然而,政策制定者和其他利益相关方在农林业作为气候变化适应战略中作用的争辩却越来越多。本研究的目的是评估农林业作为气候变化适应战略的潜力。数据主要通过问卷调查从拉姆琼县Taksar的120名受访者中收集,采用卡方检验和二元logistic模型分析了影响气候变化适应策略的家庭选择因素。同样,通过访谈、讨论和观察以及后续的文件分析,对所获得的数据进行三角互证和验证。研究表明,农民采取了许多应对气候变化的策略,这些策略包括农牧多样化(71%)、使用改良作物品种、化肥和农药(73%)、农林复合经营(68%)、创收多样化(72%)、改变作物种植日期(57%)和复种措施(67%)等。从卡方检验和二元logistic模型中发现,“耕作经验”、“教育水平”、“农场规模”和“性别”对气候变化适应策略具有显著影响。农林复合经营具有不同的效益,如增加河流汇水(79.2%)、改善小气候(80.8%)、增加木材产品(71.7%)、提高粮食产量(83.3%)、改善牲畜健康和畜产品(77.5%)、提高土壤肥力(84.2%)和多样化生计选择(82.2%)。基于这些发现,该研究得出结论:农林复合经营是一种可以减少气候变化对当地环境影响的农业生产方法,推广和采用农林业可以帮助当地社区减少气候变化的影响。

关键词：气候变化适应策略当地社区复种

A Pair of Pseudo-differential Operators Involving Index Whittaker Transform in L_(2)^(a) (R_(+);m_(a)(x)dx)

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Acta Mathematica Sinica,English Series 2024年第6期40卷 1420-1430页

作者： Jeetendrasingh MAAN Akhilesh prasad Department of Mathematics and Computing Indian Institute of Technology(Indian School of Mines)Dhanbad-826004India

Pseudo-differential operators(PDO)Q(x,L_(a,x))and Q(x,L_(a,x))involving the index Whittaker transform are *** for these operators in Hilbert space L_(2)^(a)(R+;m_(a)(x)dx)are obtained.A symbol classΩis *** product an... 详细信息

关键词： Pseudo-differential operator index Whittaker transform confluent hypergeometric functions Hilbert space

Impacts of road on plant invasions in the Middle Mountain region of central Nepal

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Journal of Mountain Science 2024年第2期21卷 619-632页

作者： Ananda ADHIKARI Adarsha SUBEDI Achyut TIWARI bharat Babu SHRESTHA Central Department of Botany Tribhuvan UniversityKirtipur 44618Nepal

Biological invasion is triggered by human development activities such as the construction and expansion of road *** verges serve as important habitats and corridors for the distribution of invasive alien plant species(IAPS)between geographically distant ***,the trajectory of plant invasion and the data regarding the impact of roads on IAPS distribution are relatively poor in ***,we surveyed two road types(main roads and feeder road)in the Middle Mountain region of central Nepal in order to investigate how different road types are driving the dispersal of IAPS along road verges and the adjacent natural *** sampling was conducted at ca 2.5 km intervals along the *** each sampling site,paired plots(25 m×4 m)were sampled:one adjacent to and along the road,and another 20 m away and parallel to it in the interior *** results revealed that the main road verges had a higher cover(33%)and a larger number of IAPS(14 species)than the feeder road(25%;10 species).The IAPS cover and richness were significantly higher along verges than in the adjacent interior habitats for both road types,indicating that roads are contributing as corridors for the dispersal of IAPS in the Middle Mountain areas of central ***,elevation,tree canopy,and disturbances(grazing/mowing/trampling)were found to be the key factors that determine spatial distribution of IAPS along road *** emphasize that regular monitoring of vegetation along the road verges can help with the early detection and control of potential IAPS in the region before they become problematic.

关键词： Biological invasions Dispersal corridor Invasive alien plants Transport infrastructure Himalayan mountains

A novel control strategy of a variable-speed doubly-fed-induction-generator-based wind energy conversion system

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CLEAN ENERGY 2024年第1期8卷 153-170页

作者： Mohapatra, Shibani prasad Dash, Pradipta Kishore Siksha O Anusandhan Deemed Univ Dept Elect Engn Bhubaneswar 751030 Odisha India Siksha O Anusandhan Deemed Univ Multidisciplinary Res Cell Bhubaneswar 751030 Odisha India

This paper aims to address the issue of control of a variable-speed wind turbine based on doubly-fed induction generators. In this work, an effort is made to extract the maximum efficiency from a doubly-fed induction generator-based variable-speed wind turbine by controlling the rotor current. In the first step, a maximum power point tracking technique is used to extract the maximum power from the turbine. Then a stator-flux-oriented vector control strategy is employed to control the rotor-side current. Subsequently, a grid voltage vector-oriented control strategy is used to control the grid-side system of the grid-connected generator. Considering the nonlinearity and parameter uncertainty of the system, an active disturbance rejection controller with a sliding-mode-based extended-state observer is developed for the above-mentioned control strategies. Furthermore, the stability of the controller is tested and the performance of the controller is compared with the classical proportional-integral controller based on disturbance rejection, robustness and tracking capability in a highly non-linear wind speed variation scenario. Modelling, control and comparison are conducted in the MATLAB (R)/Simulink (R) environment. Finally, a real-time hardware set-up is presented using the dSPACE ds-1104 R&D processing board to validate the control scheme. From the result of the experiments, it is seen that the proposed controller takes 10-15 control cycles to settle to its steady-state values, depending on the control loop, whereas the conventional proportional-integral controller takes 60-75 control cycles. As a result, the settling time for the proposed control scheme is shorter than that of the proportional-integral controller. The maximum efficiency is extracted from a doubly-fed induction generator-based variable-speed wind turbine by controlling the rotor current. A maximum power point tracking technique is used in combination with a stator-flux-oriented vector control strate

关键词： doubly-fed induction generator variable-speed wind turbine vector control active disturbance rejection controller stability analysis NONLINEAR CONTROL DFIG TURBINE

Liver transplantation as an alternative for the treatment of non-resectable liver colorectal cancer: Advancing the therapeutic algorithm

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Hepatobiliary & Pancreatic Diseases International 2024年第2期23卷 154-159页

作者： Badi Rawashdeh Richard Bell Abdul Hakeem Raj prasad Division of Transplant Surgery Department of General SurgeryMedical College of WisconsinMilwaukeeWI53226USA Leeds Teaching Hospital LeedsUK

Colorectal cancer is a leading cause of cancerrelated mortality,with nearly half of the affected patients developing liver *** three decades,liver resection(LR)has been the primary curative strategy,yet its applicability is limited to about 20%of *** transplantation(LT)for unresectable metastases was attempted unsuccessfully in the 1990s,with high rates of perioperative death and *** is now more interest in this strategy due to improvements in systemic therapies and surgical techniques.A significant study conducted by the Oslo group showed that patients receiving liver transplants had a 60%chance of survival after five *** better results have been achieved by using advanced imaging for risk stratification and further refining selection criteria,especially in the Norvegian SECA *** review carefully charts the development and history of LT as a treatment option for colorectal cancer liver *** revolutionary path from the early days of exploratory surgery to the current situation of cautious optimism is traced,highlighting the critical clinical developments and improved patient selection standards that have made LT a potentially curative treatment for such challenging very well selected cases.

关键词： Liver transplantation Colorectal cancer liver metastases Non-resectable liver metastases