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Inertisation options for BG method and optimisation using CFD modelling

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International Journal of Mining Science and Technology 2015年第3期25卷 401-405页

作者： Morla Ramakrishna Balusu Rao Tanguturi krishna Ting Ren CSIRO Earth Science and Resource Engineering Faculty of Engineering and Information Science University of Wollongong

Spontaneous combustion(sponcom) is one of the issues of concern with the blasting gallery(BG) method of coal mining and has the potential to cause fires, and impact on production and safety, greenhouse gas(GHG) emissions and huge costs involved in controlling the aftermath situations. Some of the research attempts made to prevent and control coal mine fires and spontaneous combustion in thick seams worked with bord and pillar mining methods are presented in this paper. In the study, computational fluid dynamics(CFD) modelling techniques were used to simulate and assess the effects of various mining methods, layouts, designs, and different operational and ventilation parameters on the flow of goaf gases in BG panels. A wide range of parametric studies were conducted to develop proactive strategies to control and prevent ingress of oxygen into the goaf area preventing spontaneous combustion and mine fires.

关键词： Blasting gallery method Spontaneous combustion Inertisation CFD

High-energy ion treatments of amorphous As40Se60 thin films for optical applications

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Progress in Natural Science:Materials International 2014年第3期24卷 239-246页

作者： Rashmi Chauhan Arvind Tripathi krishna Kant Srivastava Department of Physic DAV College CSJM University Research Foundation for Education and Technology Department of Physics DBS College CSJM University

The treatment of 100 MeV Ag swift-heavy ion(SHI) irradiation with five different fluences(3 1010, 1 1011, 3 1011, 1 1012, and3 1012ions/cm2) was used to design optical and structural properties of amorphous(a-) As40Se60 chalcogenide thin films. Swanepoel method was applied on transmission measurements to determine the changes in optical bandgap, Tauc parameter and linear optical parameters, i.e., linear optical absorption, extinction coefficient and linear refractive index. Dispersion of the material was determined by Wemple–DiDomenico *** in nonlinear optical parameters of third-order optical susceptibility and nonlinear refractive index were determined using semi-empirical relations. Changes in surface morphology of the films were investigated using SEM observation, which indicated that fluence 3 1012ions/cm2was upper threshold limit for these films for ion treatment. It is observed that optical bandgap reduces from 1.76 eV to 1.64 eV, and nonlinear refractive index increases from 1.31 10 10[esu] to 1.74 10 10[esu]. Linear refractive index initially increases from 2.80 to 3.52(for fluence3 1010ions/cm2) and then keeps decreasing. The observed changes in optical properties upon irradiation were explained in terms of structural rearrangements by Raman measurement. The study was compiled with the previous literature to propose SHI as an effective optical engineering technique to achieve desired changes according to the need of optical/photonic applications.

关键词： Amorphous chalcogenide thin films Ion irradiation Linear and nonlinear optical properties Swanepoel method Semi-empirical relations Raman measurements

Endosonographic diagnosis of advanced neoplasia in intraductal papillary mucinous neoplasms

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World Journal of Gastroenterology 2020年第23期26卷 3201-3212页

作者： Andrew Eiterman Ali Lahooti Somashekar G krishna Department of Internal Medicine The Ohio State University Wexner Medical CenterColumbusOH 43210United States Division of Gastroenterology Hepatologyand NutritionThe Ohio State University Wexner Medical CenterColumbusOH 43210United States

Pancreatic cancer has a high mortality rate with minimal proven *** Papillary Mucinous Neoplasms(IPMNs) are known precursor lesions for pancreatic cancer. Identification of pancreatic cysts has improved from advances in abdominal imaging. Despite multiple revisions of the international consensus recommendations and various guidelines by other major societies,successful risk stratification of the malignant potential of mucinous pancreatic cysts remains challenging. Specifically, detection and accurate classification of advanced neoplasia(high-grade dysplasia and/or adenocarcinoma) in IPMNs is suboptimal with current diagnostic strategies. Development of interventional techniques utilizing endoscopic ultrasound include-through-the-needle microforceps biopsy, next-generation or whole genome molecular analysis of cyst fluid, and needle-based confocal laser endomicroscopy. These techniques suffer from a series of limitations in technical success, diagnostic yield, and clinical feasibility, but a combination approach may offer a solution that optimizes their cyst evaluation and risk stratification. Assessment and comparison of these techniques is restricted by lack of adequate surgical specimens for testing of diagnostic accuracy, resulting in a possible sample bias. Additional large-scale multicenter studies are needed to accumulate evidence for the utility and feasibility of their translation into clinical practice. Great strides have been made in pancreatic cyst evaluation, but further research is required to improve diagnostic accuracy and clinical management of IPMNs.

关键词： Pancreatic cyst Confocal endomicroscopy Microforceps biopsy Cyst fluid molecular analysis Endoscopic ultrasound Intraductal papillary mucinous neoplasms

Current status of the biliary tract malformation

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World Journal of Clinical Pediatrics 2024年第2期13卷 100-103页

作者： krishna Kumar Govindarajan Department of Pediatric Surgery JIPMERPondicherryPondicherry 605006India

The choledochal cyst(CC)can be better termed as biliary tract malformation because of the close association of embryology and etiology in the causation of *** to Babbitt's postulation of reflux,damage and dilatation,reflux was not demonstrable as the causative factor in all varieties of *** pressure in the biliary system,otherwise termed ductal hypertension,is put forth as an alternative to explain the evolution of *** forme fruste type,which does not find a place in the standard classification,typifies the ductal hypertension *** a closer,in-depth review would be able to highlight this apt terminology of biliary tract malformation.

关键词： Choledochal cyst Biliary tract Biliary dilatation Ductal hypertension Common channel Pancreatobiliary malunion

Investigations on Low Speed Axial Compressor with Forward and Backward Sweep

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Journal of Thermal Science 2007年第2期16卷 121-133页

作者： M.Govardhan O.G.krishna Kumar N.Sitaram Thermal Turbomachines Laboratory Department of Mechanical EngineeringIndian Institute of Technology MadrasChennai 600036India

In the recent past, experimental studies have shown some advantages of blade lean and sweep in axial compressors. As most of the experimental results are combined with other features, it is difficult to determine the effect of individual parameters on the performance of the compressor. The present numerical studies are aimed at understanding the performance and three-dimensional flow pattern at the exit of swept and unswept rotors. Three rotors, namely; unswept, 200 forward swept and 200 backward swept rotors are analysed with a specific intention of understanding the pattern of the blade boundary layer flow. The analysis was done using a fully three-dimensional viscous CFD code CFX-5. Results indicated reduction in pressure rise with sweep. Backward sweep is detrimental as far as the performance near endwalls is considered. On the other hand total pressure loss in the wake in mid span region is less with backward sweep, which favours its application here. However, backward sweep adversely affects the stall margin. The ability of the forward sweep to deflect the streamlines towards hub gets diminished at low flow rates. Forward sweep changes the streamline pattern in such a way that the suction surface streamlines are deflected towards the hub and the pressure surface streamlines are deflected towards the easing. An opposite behaviour is observed in backward swept rotors.

关键词： Sweep pressure rise streamline shift stall margin blade loading

Mathematical modelling on diffusion and control of COVIDe19

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Infectious Disease Modelling 2020年第1期5卷 588-597页

作者： M.Veera krishna Department of Mathematics Rayalaseema UniversityKurnoolAndhra Pradesh518007India

In this paper,we develop a mathematical model for the spread and control of the coronavirus *** outbreak of COVID-19 has led to more than one million confirmed cases as of April 3rd,*** the early spread dynamics of the infection and evaluating the effectiveness of control measures is crucial for assessing the potential for sustained transmission to occur in new *** a mathematical model of severe COVID-19 spread with four datasets from within and outside of Wuhan,China;it is estimated how spread in Wuhan varied between January and February *** is used these estimates to assess the potential for sustained human-to-human spread to occur in locations outside Wuhan if disease holders were *** is combined SEIR framework model with data on cases of COVID-19 in China and International cases that originated in Wuhan to estimate how spread had varied over time during January and February *** on these estimates,it is calculated the probability that freshly introduced cases might produce outbreaks in other ***,it is calculated approximately the median day by day basic reproduction number in Wuhan,refused from 2$45(95%CI:1.16-4.87)one week before travel restrictions were introduced on Jan 23rd,2020,to 1.05(0.42-2.40)one week *** on our estimates of,presumptuous SARS approximating disparity,it is computed that in locations with a similar spread potential to Wuhan in near the beginning of January,some time ago there are at least four independently set up cases,there is a more than fifty percent chance the infection will found within those ***-19 spreading probably refused in Wuhan during delayed January 2020,corresponding with the prologue of voyage control *** more cases arrive in international locations with similar spread potential to Wuhan,before these organize measures,it is likely many chains of spread will fail to create initially but might lead to innovative outbreaks ultimately.

关键词： COVID-19 Coronavirus Mathematical modelling Diffusion Reproduction number

The Rationale for Reviewing Current Concepts of Urban Planning and Developing New Ones in India

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Built Heritage 2017年第3期1卷 34-43页

作者： A.G.krishna Menon Departments of Architecture and Urban Design School of Planning and ArchitectureNew DelhiIndia

Urban planning in India is heir to a colonial paradigm that imposed practices developed from the experiences of Western urbanisation to the local Indian *** paper suggests that this paradigm exacerbates the complex problems of contemporary urbanisation,but there is little attempt among Indian urban planners to acknowledge and address the consequences of their colonial *** forces of globalisation are reinforcing this postcolonial intellectual malaise by reposing greater faith in capital-and technology-intensive solutions to solve problems instead of reforming the inherited processes of urban *** paper argues that the nascent field of urban conservation in India offers the potential to review the dominant paradigms of urban planning and develop more context-specific and appropriate strategies for tackling the problems of Indian urbanisation.

关键词： historic space historic metropolitan context evolution reflection

Influence of Nano-Materials on Mechanical and Permeation Characteristics of High Strength Concrete

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Journal of Wuhan University of Technology(Materials Science) 2022年第3期37卷 416-422页

作者： K V S Gopala krishna Sastry M Srinivasula Reddy A Ravitheja Civil Engineering G Pulla Reddy Engineering CollegeKurnoolAPIndia SVR Engineering College NandyalAndhra PradeshIndia

Efforts have been made to evaluate the influences of the addition of nanoparticles on the strength,durability and mineralogical changes of high strength concrete(HSC).Therefore,mixes were prepared for conventional concrete mix(CCM)of M80 ***,various mixes were prepared by replacing cementitious materials initially with 1%Nano-CaCO_(3)(NC),2%NC,3%NC in the CCM,and then 1%NC and Nano-SiO_(2)(NS)NS,2%NC and NS,3%NC and NS(NC and NS were in equal proportion)in the *** developed concretes were then evaluated for mechanical properties,permeation characteristics,and mineralogical *** the studies,it is found that the concrete at 2%NCS possesses superior mechanical and superior permeation characteristics of all the mixes.A clear variation in the mineralogical structure with the addition of nanoparticles has been observed.

关键词： high strength concrete nano silicon dioxide nano calcium carbonate mechanical properties permeation properties

How does the stand structure of treeline-forming species shape the treeline ecotone in different regions of the Nepal Himalayas?

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Journal of Mountain Science 2020年第10期17卷 2354-2368页

作者： Parveen K.CHHETRI Raju BISTA krishna B.SHRESTHA Department of Earth Science and Geography California State UniversityDominguez HillsCarsonCalifornia90747USA Department of Biological Sciences University of BergenPO Box 7803N-5020BergenNorway

Stand structure dynamics are considered as major happenings in any forest as a response to environmental ***,this important topic is underrepresented in the treeline studies in the Nepal *** aimed to investigate site-as well as species-specific changes in morphometric features(basal diameter,crown cover,density,and height)along the elevational gradient across treeline ecotones in response to recent environmental *** stand structure characteristics of Abies spectabilis,Pinus wallichiana,and Betula utilis across the treeline ecotone of three study sites in Eastern(Barun),Central(Manang),and Western(Dhorpatan)Nepal were analyzed to elucidate structural ***,eight transects(20 m×(60–250 m))across the treeline ecotone were *** of all life forms,trees(>2 m),saplings(0.5–2 m),and seedlings(<0.5 m),within each transect were enumerated and sampled for the morphometric features and ***-specific and species-specific stand structure dynamics were *** rate of basal area increment was higher in Barun,but the Manang treeline,despite profound regeneration in recent years,had a low annual basal area ***,the altitudinal distribution of age and morphometry were not consistent among those ***,intra-specific competition was not *** site-specific stand structure dynamics explain why treelines do not respond uniformly to increasing *** invokes,in further studies,the incorporation of the tree’s morphometric adaptation traits,phenotypic plasticity,and interactions between species genotype and the environment.

关键词： Climate change Morphometry Nepal Himalayas Stand structure Treeline Tree-rings