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Search for H I emission from superdisk candidates associated with radio galaxies

Research in Astronomy and Astrophysics 2019年第6期19卷 71-78页

作者： Abhijeet Anand Nirupam Roy gopal-krishna Max-Planck-Institut fur Astrophysik Karl-Schwarzschild-Str. 1 D-85741 Garching Germany Department of Physics Indian Institute of Science Bangalore - 560012 India Aryabhatta Research Institute of Observational Sciences (ARIES) Manora Peak Nainital - 263129 India Max-Planck-Institut fur Radioastronomie Auf dem Hugel 69 53121 Bonn Germany

giant gaseous layers(termed “superdisks”) have been hypothesized in the past to account for the strip-like radio emission gap(or straight-edged central brightness depression) observed between twin radio lobes, in over a dozen relatively nearby powerful Fanaroff-Riley Class II radio galaxies. They could also provide a plausible alternative explanation for a range of observations. Although a number of explanations have been proposed for the origin of the superdisks, little is known about their material content. Some X-ray observations of superdisk candidates indicate the presence of hot gas, but a cool dusty medium also seems to be common. If they are entirely or partly composed of neutral gas, then it may be directly detectable and we report here a first attempt to detect/image any neutral hydrogen gas present in the superdisks that are inferred to be present in four nearby radio galaxies. We have not found a positive H I signal in any of the four sources, resulting in tight upper limits on the H I number density in the postulated superdisks,estimated directly from the central rms noise values of the final radio continuum subtracted image. The estimated ranges of the upper limit on neutral hydrogen number density and column density are 10^-4-10^-3 atoms per cm3 and 10^19-10^20 atoms per cm^2, respectively. No positive H I signal is detected even after combining all the four available H I images(with inverse variance weighting). This clearly rules out an H I dominated superdisk as a viable model to explain these structures, however, the possibility of a superdisk being composed of warm/hot gas still remains open.

关键词： galaxies:active galaxies:general galaxies:structure radio lines:galaxies

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Analysis of unlined pressure shafts and tunnels of selected Norwegian hydropower projects

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Journal of Rock Mechanics and geotechnical Engineering 2018年第3期10卷 486-512页

作者： Chhatra Bahadur Basnet krishna Kanta Panthi Department of geoscience and Petroleum Norwegian University of Science and Technology

Norwegian hydropower industry has more than 100 years of experiences in constructing more than4000 km-long unlined pressure shafts and tunnels with maximum static head of 1047 m（equivalent to almost 10.5 MPa） reached at unlined pressure tunnel of Nye Tyin project. Experiences gained from construction and operation of these unlined pressure shafts and tunnels were the foundation to develop design criteria and principles applied in Norway and some other countries. In addition to the confinement criteria, Norwegian state-of-the-art design principle for unlined pressure shaft and tunnel is that the minor principal stress at the location of unlined pressure shaft or tunnel should be more than the water pressure in the shaft or tunnel. This condition of the minor principal stress is prerequisite for the hydraulic jacking/splitting not to occur through joints and fractures in rock mass. Another common problem in unlined pressure shafts and tunnels is water leakage through hydraulically splitted joints or pre-existing open joints. This article reviews some of the first attempts of the use of unlined pressure shaft and tunnel concepts in Norway, highlights major failure cases and two successful cases of significance, applies Norwegian criteria to the cases and reviews and evaluates triggering factors for *** article further evaluates detailed engineering geology of failure cases and also assesses common geological features that could have aggravated the failure. The minor principal stress is investigated and quantified along unlined shaft and tunnel alignment of six selected project cases by using threedimensional numerical model. Furthermore, conditions of failure through pre-existing open joints by hydraulic jacking and leakage are assessed by using two-dimensional fluid flow analysis. Finally, both favorable and unfavorable ground conditions required for the applicability of Norwegian confinement criteria in locating the unlined pressure shafts and tunnels for ge

关键词： Hydropower projects Unlined pressure shafts and tunnels Minor principal stress Hydraulic jacking Water leakage

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Rock-like behavior of biocemented sand treated under non-sterile environment and various treatment conditions

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Journal of Rock Mechanics and geotechnical Engineering 2021年第3期13卷 705-716页

作者： Meghna Sharma Neelima Satyam krishna RReddy Discipline of Civil Engineering Indian Institute of Technology IndoreIndore453552India Department of Civil Materialsand Environmental EngineeringUniversity of Illinois at ChicagoChicagoILUSA

Microbially induced calcite precipitation(MICP)is a recently developed technique for microbiological ground improvement that has been applied for mitigating various geotechnical ***,the major challenges,such as calcite precipitation uniformity,presence of different bacteria,cementation solution optimization for cost reduction,and implementation under non-sterile and uncontrolled field environment are still not fully explored and require detailed investigation before field *** study aims to address these challenges of MICP to improve the geotechnical properties of sandy *** series of experiments were conducted using poorly graded Narmada River(India)sand,which were subjected to various biotreatment schemes and tested for unconfined compressive strength(UCS),split tensile strength(STS),ultrasonic pulse velocity(UPV),hydraulic conductivity(after 6 d,12 d,and 18 d of treatment),and calcite *** microstructure of sand was examined through a scanning electron microscope(SEM).Initially,the sand was individually augmented with two non-pathogenic bacterial strains,***(S.)pasteurii and Bacillus(B.)*** stopped-flow injection method was adopted to provide cementation solutions at three different durations(treatment cycle)of 12 h,24 h,and 48 h and three different pore volumes(PVs)of 1,0.75,and *** pore volume here refers to the porosity which is expressed as a ratio,i.e.a porosity of 50%was used as *** results showed rock-like behaviors of biocemented sand with the UCS,STS,and UPV enhancement up to 2333 kPa,437 kPa,and 2670 m/s,*** hydraulic conductivity reduction of 96.6%was achieved by 12%of calcite formation after 18 d of treatment using Sporosarcina pasteurii,12-h treatment cycle,and one pore volume of cementation media in each ***,a 24-h treatment cycle and 0.5-pore volume cementation solution were found to be the optimal treatment which was effective and economical to achiev

关键词： Bacteria Microbially induced calcite precipitation (MICP) Soil stabilization Microstructure Calcite content

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On the spatio-temporal variation in b-value after 25 April 2015 gorkha,Nepal earthquake

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geodesy and geodynamics 2022年第5期13卷 525-533页

作者： Ram krishna Tiwari Harihar Paudyal Daya Shanker Central Department of Physics Tribhuvan UniversityKirtipurKathmanduNepal Birendra Multiple Campus Tribhuvan UniversityBharatpurChitwanNepal Department of Earthquake Engineering Indian Institute of Technology RoorkeeRoorkeeUttarakhandIndia

In the present study,the spatial-temporal distribution of b-value along the five faults area(the Judi fault,Thaple fault,Kathmandu fault,Motihari-gauri Shanker fault,and Motihari-Everest fault)was investigated after the gorkha earthquake(M7.8).The earthquake catalog of 10,500 events was prepared by compiling the published *** study area is bounded in the central Himalaya from 26.5°to 29°in latitude direction and 84°to 87°in longitude *** frequency magnitude distribution shows the variation of the b-value along with fault areas from 0.45 to 0.69,indicating a common characteristic of aftershock *** particular,the Judi fault area,Thaple fault area,and Motihari-Everest fault area are characterized by the low b-values of 0.45±0.02,0.48±0.02,and 0.55±0.04,*** regions could be the source region for future *** low b-value observed for fault areas are also consistent with the thrust faulting pattern in the region as indicated by the focal mechanism of mainshock and major *** temporal variation of b-value shows inevitable fluctuations during25 April to 12 May *** the area selected,the Motihari-Everest fault area is in critical strain(mechanically locked)conditions,as indicated by the stepwise energy release pattern.

关键词： Frequency-magnitude distribution Time series analysis Thrust fault Stress Central Himalaya

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Assessing the effectiveness of community managed forests for plant diversity conservation in Meghalaya,Northeast India

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Plant Diversity 2022年第3期44卷 243-254页

作者： Aabid Hussain Mir Kiranmay Sarma krishna Upadhaya Department of Environmental Studies North-Eastern Hill UniversityShillong793022MeghalayaIndia University School of Environment Management Guru Gobind Singh Indraprastha UniversityDwarka 16CNew Delhi110075India Department of Basic Sciences and Social Sciences North-Eastern Hill UniversityShillong793022MeghalayaIndia

In the state Meghalaya,northeast India,>80%of the forest lands are owned by local communities and managed by traditional *** forests are under severe threats due to a number of human *** present study was conducted to assess the plant diversity and identify the community forests for priority conservation in Khasi Hills of *** explorations carried out in the 87 forests reveals the presence of 1300 plant species of which 400 are either rare,endemic or *** the different forest categories,reserve forests had the highest number of species(1190),followed by sacred forests(987 species)and village forests(786 species).Majority of the forests(56)had high-species richness,irreplaceability level(42 forests)and vulnerability level(54).In terms of area,13.8%(1666.8 ha)fall under low risk while 1855 ha under high risk *** risk zone was mostly represented by village *** area of 7661.56 ha of community forests falls under high priority category and hence calls for immediate conservation *** conservation priority map generated in the present study will help to concentrate the protection strategy to the demarcated and adjoining areas and help conservationists and planners to evolve effective strategies for conservation of the community forests.

关键词： Conservation Disturbance Endemic Rare Threatened Village forest

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An assessment of population structure and regeneration status of Magnolia punduana Hk. f. & Th.(Magnoliaceae) in fragmented forests of northeast India

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Journal of Forestry Research 2020年第3期31卷 937-943页

作者： Viheno Iralu Ngakhainii Trune Pao krishna Upadhaya Department of Environmental Studies School of Human and Environmental SciencesNorth-Eastern Hill UniversityShillong 793022India Department of Basic Sciences and Social Sciences School of TechnologyNorth-Eastern Hill UniversityShillong 793022India

The population structure and regeneration status of Magnolia punduana Hk. f. & Th., an endemic tree species of northeast India were investigated in fragmented forests in the Jarain Hills and in adjoining areas of Meghalaya state. The population structure was discontinuous in all the fragments with the absence of individuals in higher diameter classes. The number of individuals increased with the size of the fragment patches(p gh(24–30 individuals ha-1) in the largest fragment(>105 ha). The number of seedlings and saplings were also higher in the larger fragments. Human-related disturbances had a negative impact on the species population(pgment size, site characteristics and ongoing human disturbances. The restricted distribution of the species coupled withexploitation and habitat destruction underlines the need for its conservation.

关键词： Conservation Disturbance Fragmentation Magnolia punduana Restricted distribution

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A threshold voltage model of short-channel fully-depleted recessed-source/drain(Re-S/D) SOI MOSFETs with high-k dielectric

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Chinese Physics B 2015年第10期24卷 604-611页

作者： gopi krishna Saramekala Sarvesh Dubey Pramod Kumar Tiwari Department of Electronics and Communication Engineering National Institute of Technology Shri Ramswaroop Memorial University

In this paper, a surface potential based threshold voltage model of fully-depleted（FD） recessed-source/drain（Re-S/D）silicon-on-insulator（SOI） metal-oxide semiconductor field-effect transistor（MOSFET） is presented while considering the effects of high-k gate-dielectric material induced fringing-field. The two-dimensional（2D） Poisson＇s equation is solved in a channel region in order to obtain the surface potential under the assumption of the parabolic potential profile in the transverse direction of the channel with appropriate boundary conditions. The accuracy of the model is verified by comparing the model＇s results with the 2D simulation results from ATLAS over a wide range of channel lengths and other parameters,including the dielectric constant of gate-dielectric material.

关键词： recessed-source/drain (Re-S/D) high-k gate-material fringing field and SCEs

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Illumination-Free Clustering Using Improved Slime Mould Algorithm for Acute Lymphoblastic Leukemia Image Segmentation

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Journal of Bionic Engineering 2023年第6期20卷 2916-2934页

作者： krishna gopal Dhal Swarnajit Ray Sudip Barik Arunita Das Department of Computer Science and Application Midnapore College(Autonomous)Paschim MedinipurMidnaporeWest BengalIndia Department of Computer Science and Engineering Maulana Abul Kalam Azad University of TechnologyKolkataWest BengalIndia Department of Computer Science and Engineering Kalyani Government Engineering CollegeKalyaniWest BengalIndia

Partitional clustering techniques such as K-Means(KM),Fuzzy C-Means(FCM),and Rough K-Means(RKM)are very simple and effective techniques for image ***,because their initial cluster centers are randomly determined,it is often seen that certain clusters converge to local *** addition to that,pathology image segmentation is also problematic due to uneven lighting,stain,and camera settings during the microscopic image capturing ***,this study proposes an Improved Slime Mould Algorithm(ISMA)based on opposition based learning and differential evolution’s mutation strategy to perform illumination-free White Blood Cell(WBC)*** ISMA helps to overcome the local optima trapping problem of the partitional clustering techniques to some *** paper also performs a depth analysis by considering only color components of many well-known color spaces for clustering to find the effect of illumination over color pathology image *** and visual results encourage the utilization of illumination-free or color component-based clustering approaches for image ***-KM and“ab”color channels of CIELab color space provide best results with above-99%accuracy for only nucleus ***,for entire WBC segmentation,ISMA-KM and the“CbCr”color component of YCbCr color space provide the best results with an accuracy of above 99%.Furthermore,ISMA-KM and ISMA-RKM have the lowest and highest execution times,*** the other hand,ISMA provides competitive outcomes over CEC2019 benchmark test functions compared to recent well-established and efficient Nature-Inspired Optimization Algorithms(NIOAs).

关键词： Pathology image Image segmentation Clustering Color space White blood cell Optimization Swarm intelligence Fuzzy clustering Rough clustering

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Extrahepatic metastasis of hepatocellular carcinoma to the paravertebral muscle:A case report

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World Journal of Hepatology 2017年第22期9卷 973-978页

作者： Kazuhiro Takahashi krishna g Putchakayala Mohamed Safwan Dean Y Kim Transplant and Hepatobiliary Surgery Henry Ford HospitalDetroitMI 48202United States

Identification of extrahepatic metastases(EHM) of hepatocellular carcinoma(HCC) has been paradoxically increasing due to an increase in the survival of HCC patients. However, metastasis of HCC to the skeletal muscle tissue is extremely rare. We describe a unique case of HCC metastasizing to the paravertebral muscle. A 55-year-old man with a history of hepatitis B cirrhosis underwent partial liver resection with complete removal of HCC. Three months later, a computed tomography(CT) scan showed intrahepatic recurrence. The tumors were treated with yttrium-90 microspheres, transcatheter arterial chemoembolization, and sorafenib. Six months later, a CT scan showed an enhancing lesion of the left paravertebral muscle that on biopsy were consistent with metastatic HCC. The tumor was treated with stereotactic hypo-fractionated imageguided radiation therapy(SHFRT). A follow-up scan 3 mo post-radiotherapy revealed a stable appearance of the paravertebral muscle metastasis. Because of the progression in the intrahepatic tumors, the patient was treated with capecitabine, which was changed to dasatinib 6 mo later. The patient passed away three years after the primary surgical resection. Management of EHM poses an extreme challenge. This is the first case of HCC with EHM to the paravertebral muscle in which stability of disease was achieved using SHFRT. This case highlights the importance of early detection of hepatitis B viral infection and initiation of anti-viral therapy to decrease recurrence of HCC and prevent EHM.

关键词： Hepatocellular carcinoma Skeletal muscle Paravertebral muscle Extrahepatic metastasis Stereotactic hypo-fractionated image guided radiation therapy Hepatitis B virus

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Diagnosis of COVID-19 from Chest X-Ray Images Using Wavelets-Based Depthwise Convolution Network

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Big Data Mining and Analytics 2021年第2期4卷 84-93页

作者： krishna Kant Singh Akansha Singh Department of ECE KIET Group of InstitutionsDelhi-NCRGhaziabad 201206India Department of CSE ASETAmity University Uttar PradeshNoida 201310India

Coronavirus disease 2019 also known as COVID-19 has become a pandemic. The disease is caused by a beta coronavirus called Severe Acute Respiratory Syndrome Coronavirus 2(SARS-Co V-2). The severity of the disease can be understood by the massive number of deaths and affected patients globally. If the diagnosis is fast-paced, the disease can be controlled in a better manner. Laboratory tests are available for diagnosis, but they are bounded by available testing kits and time. The use of radiological examinations that comprise Computed Tomography(CT) can be used for the diagnosis of the disease. Specifically, chest X-Ray images can be analysed to identify the presence of COVID-19 in a patient. In this paper, an automated method for the diagnosis of COVID-19 from the chest X-Ray images is proposed. The method presents an improved depthwise convolution neural network for analysing the chest X-Ray images. Wavelet decomposition is applied to integrate multiresolution analysis in the network. The frequency sub-bands obtained from the input images are fed in the network for identifying the *** network is designed to predict the class of the input image as normal, viral pneumonia, and COVID-19. The predicted output from the model is combined with grad-CAM visualization for diagnosis. A comparative study with the existing methods is also performed. The metrics like accuracy, sensitivity, and F1-measure are calculated for performance evaluation. The performance of the proposed method is better than the existing methodologies and thus can be used for the effective diagnosis of the disease.

关键词： coronavirus COVID-19 deep learning convolution neural network X-Ray images

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