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Hydro-elastic computational analysis of a marine propeller using two-way fluid structure interaction

Journal of Ocean Engineering and Science 2022年第3期7卷 280-291页

作者： V.Rama krishna Srinivas prasad Sanaka N.Pardhasaradhi B.Raghava Rao Naval Science&Technological Laboratory Visakhapatnam532007India Department of mechanical Engineering V.R.Siddhartha Engineering CollegeVijayawada520007India

marine propellers have complex geometry and their performance is determined by costly and time consuming open water *** of numerical techniques helps researchers in effective design of *** approaches are used that predicted either hydrodynamic and acoustic response or structural ***-way fluid-structure interaction(FSI)analysis is a very useful approach providing all three responses which helps in the design,analysis and optimization of a *** objective of this paper is to predict the hydro-elastic response of a propeller using two-way FSI on a 0.2m diameter,DTmB-4119 propeller using ANSYS ***-way FSI analysis is carried out using system coupling approach that transfers the data between the structural and fluid *** turbulence effects are captured using the large-eddy simulation(LES)model and the Ffowcs Williams Hawkings(FWH)acoustic model is used for evaluating the sound pressure level(SPL)generated by *** is extended to evaluate the hydro-elastic and acoustic response of the propeller after validating the hydrodynamic performance with the experimental result in the *** results from Two-way FSI analysis are in close agreement when compared with the one-way FSI ***-way FSI can accommodate the peak value of stress and deformation developed during the initial part of the transient solution which is important in the design of *** study reveals that metallic(NAB)propeller can be replaced by a composite *** acoustic response from two-way FSI analysis will be more realistic due to the consideration of hydro-elastic effect of propeller.

关键词： Advance ratio Coupled analysis CFD marine propeller Hydrodynamic parameters Two-way fluid structure interaction

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Composition of forests and vegetation in the Kailash Sacred Landscape,Nepal

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Journal of Forestry Research 2020年第5期31卷 1625-1635页

作者： Ripu mardhan Kunwar maria Fadiman Tobin Hindle madan krishna Suwal Yagya prasad Adhikari Kedar Baral Rainer Bussmann Department of Geosciences Florida Atlantic University777 Glades RoadBoca RatonFL 33431USA Department of Geography University of BergenFosswinckelsgate 6P.O.Box 78025020 BergenNorway Department of Biogeography University of BayreuthUniversitatsstr.3095447 BayreuthGermany Department of Forests Kathmandu 44600Nepal Ilia State University Kakutsa Cholokashvili Ave 3/50162 TbilisiRepublic of Georgia

A total of 141 quadrats were sampled using stratified random sampling to study forest,environment and human interactions along an elevation gradient 1800 to 3665 m at the remote Kailash Sacred Landscape,*** forest types were identified,including Laurel-Oak to Rhododendron to Blue pine,comprising 191 species including 60 useful from 166 genera and 87 *** environmental variables elevation,slope,and temperature were significant(pmining the composition and distribution of forest *** of large numbers of useful plants along with diverse forest and vegetation types suggest a strong association between the culture of local villages and nature *** to changes in climate,socio-culture and land-use,forest degradation is expected to accelerate,thus forcing government and indigenous community forest management measures to acknowledge human,cultural and environmental variables for sustainable forest management.

关键词： Phyto-sociological assessment Environmental factors Forest types Culture Kailash Sacred Landscape Nepal

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Development of Palmprint Verification System Using Biometrics

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软件学报 2006年第8期17卷 1824-1836页

作者： G. Shobha m. krishna S.C. Sharma R.V. College of Engineering Mysore Road Bangalore 560059 India

Palmprint verification system using Biometrics is one of the emerging technologies, which recognizes a person based on the principle lines, wrinkles and ridges on the surface of the palm. These line structures are stable and remain unchanged throughout the life of an individual. more importantly, no two palmprints from different individuals are the same, and normally people do not feel uneasy to have their palmprint images taken for testing. Therefore palmprint recognition offers a promising future for medium-security access control systems. In this paper, a new approach for personal authentication using hand images is discussed. Gray-Scale palm images are captured using a digital camera at a resolution of 640×480. Each of these gray-scale images is aligned and then used to extract palmprint and hand geometry features. These features are then used for authenticating users. The image acquisition setup used here is inherently simple and it does not employ any special illumination nor does it use any pegs that might cause any inconvenience to users. Experimental results show that the designed system achieves an acceptable level of performance.

关键词：灰色图象边缘追踪顶点检测验证系统

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Influence of cerium ions on structure-dependent magnetic properties of Ba-Sr m-type hexaferrite nanocrystals

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Journal of Rare Earths 2024年第2期42卷 364-372,I0005页

作者： Ram A.Pawar Sunil m.Patange P.m.Dighe Sher Singh meena Abdullah GAl-Sehemi mehboobali Pannipara Santosh S.Jadhav Department of Physics ArtsCommerce and Science CollegeAhmednagar413711MaharashtraIndia Department of Physics Shri Krishna MahavidyalayaGunjotiDistOsmanabad413606MaharashtraIndia Padmashri Vikhe Patil College of Arts Science and CommercePravaranagarA/P.Loni(Kd)Tal.RahataDistAhmednagar413713MaharashtraIndia Solid State Physics Division Bhabha Atomic Research CentreMumbai400085MaharashtraIndia Department of Chemistry King Khalid UniversityAbha61413Saudi Arabia Department of Physics D.S.M's ArtsCommerce and Science CollegeJintur431509MaharashtraIndia

The present study is a systematic effort to investigate the structure-sensitive magnetic parameters of Ce^(3+) substituted Ba-Sr hexaferrite nanocrystals chemically formulated as Ba_(0.5)Sr_(0.5)Ce_(x)Fe_(12-x)O_(19) where x=0.0-0.2 with Δx=*** hexaferrite powders were prepared using the sol-gel self-ignition route and structurally characterized by means of powder X-ray diffraction and Fourier transform infrared *** creation of the m-type hexaferrite phase within the synthesized samples was revealed from the Rietveld refinement of the X-ray *** occurrence of a secondary phase of CeO_(2) was revealed within the hexaferrites for the substitution,x> *** refined X-ray diffraction data were utilized to compute the lattice parameters,X-ray density,and lattice parameter *** crystal structure plotted from the refined XRD data reveals the occupancy of the ions at different lattice *** XPS data of the hexaferrite were analyzed to confirm the oxidation states of the constituent *** nanocrystalline nature of the hexaferrites was revealed from the crystallite sizes calculated using Scherer's *** analysis of FTIR spectra confirms that only a fraction of Ce^(3+)accommodated in the lattice and the remaining Ce content reside in the form of the CeO_(2) *** morphology of the hexaferrites was analyzed from the FESEm profiles of the ferrite *** magnetic behavior study was performed by analyzing the Curie temperature,hysteresis loops,and hyperfine interactions by means of susceptibility,V.S.m,and mossbauer spectroscopy,*** hexaferrites with increasing coercivity,decreasing saturation magnetization,and decreasing Curie temperature are reported in the *** substituted Ce^(3+)ions inhibit the grain growth and create lattice imperfections giving rise to hexaferrites with tuned magnetic parameters suitable for different applications.

关键词： Ba-Sr hexaferrite Ce^(3+)substitution XPS Saturation magnetization Coercivity m?ssbauer spectroscopy

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Dielectric Function of Silicon Nanoclusters: Role of Hydrogen

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Chinese Physics Letters 2011年第9期28卷 241-244页

作者： SIB krishna Ghoshal m.R.Sahar m.S.Rohani Advanced Optical material Research Group Department of PhysicsFaculty of ScienceUniversiti Teknologi Malaysia81310 UTM SkudaiJohorMalaysia

Electronic and optical properties of small silicon quantum dots having 3 to 44 atoms per dot with and without surface passivation are investigated by computer simulation using the pseudo-potential *** empirical pseudo-potential Hamiltonian,a plane-wave basis expansion and a basic tetrahedral structure with undistorted local bonding configurations are *** structures of the quantum dots are relaxed and optimized before and after hydrogen *** is found that the gap increases more for a hydrogenated surface than the unpassivated ***,both quantum confinement and surface passivation determine the optical and electronic properties of Si quantum *** luminescence is probably due to the radiative recombination of electrons and holes in the quantum-confined *** effect of passivation of the surface dangling bonds by hydrogen atoms and the role of surface states on the gap energy is also *** results for the density of states,the dielectric function,the frequency dependent optical absorption cross section,the extinction coefficient and the static dielectric constants of the size are *** importance of the confinement and the role of surface passivation on the optical effects are discussed.

关键词： quantum dielectric extinction

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Review of pharmacologic and immunologic agents in the management of COVID-19

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Biosafety and Health 2021年第3期3卷 148-155页

作者： marzuq A.Ungogo mustapha mohammed bala N.Umar Auwal A.bala Garba m.Khalid Department of Veterinary Pharmacology and Toxicology Ahmadu Bello UniversityZaria 810107Kaduna StateNigeria Institute of Infection Immunity and InflammationCollege of MedicalVeterinary and Life SciencesUniversity of GlasgowGlasgow G128TAUnited Kingdom School of Pharmaceutical Sciences Universiti Sains Malaysi1Penang City 11800Pulau Pinang StateMalaysia Department of Clinical Pharmacy and Pharmacy Practice Ahmadu Bello UniversityZaria 810107Kaduna StateNigeria Department of Veterinary microbiology Faculty of Veterinary MedicineAhmadu Bello UniversityZaria 810107Kaduna StateNigeria Department of Pharmacology College of Medicine and Health SciencesFederal UniversityDutse 720231Jigawa StateNigeria Faculty of Pharmaceutical Sciences Bayero UniversityKano P.M.B.3011Kano StateNigeria Department of Pharmaceutical Sciences UniversitàDegli Studi di MilanoVia G.Colombo71Milano 20133Italy

The novel coronavirus disease 2019(COVID-19)is the third coronavirus outbreak in the last two *** and re-emerging infections like COVID-19 pose serious challenges of the paucity of information and lack of specific cure or *** leaves utilisation of existing scientific data on related viral infections and repurposing relevant aetiologic and supportive therapies as the best control approach while novel strategies are developed and *** promising antiviral agents including lopinavir,ritonavir,remdesivir,umifenovir,darunavir,and oseltamivir have been repurposed and are currently trialled for the care for COVID-19 *** therapies for the management of symptoms and to provide support especially in severe and critically ill patients have also been *** review provides an appraisal of the current evidence for the rational use of frontline therapeutics in the management of *** also includes updates regarding COVID-19 immunotherapy and vaccine development.

关键词： SAR-CoV-2 COVID-19 Respiratory Drug repurposing Antiviral Supportive therapy Immunotherapy

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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

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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

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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

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microstructure and mechanical properties of similar and dissimilar metal gas tungsten constricted arc welds:maraging steel to 13-8 mo stainless steel

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Defence Technology（防务技术） 2019年第1期15卷 111-121页

作者： C.V.S.murthy A.Gopala krishna G.m.Reddy Defence Research and Development Laboratory Jawaharlal Nehru Technological University Defence metallurgical Research Laboratory

maraging steel (250) and 13-8 mo stainless steel plates were joined by gas tungsten constricted arc welding(GTCAW) process in similar and dissimilar metal combinations using 13-8 mo stainless steel filler wire. The similar and dissimilar metal welds made in solutionized condition were subjected to standard post weld hardening treatments direct ageing at 485 ℃, soaking for 31/2 hours followed by air cooling(ageing treatment of maraging steel) and direct ageing at 510 ℃, soaking for 4 h followed by air cooling(ageing treatment of 13-8 mo stainless steel). The joint characterization studies include microstructure examination, microhardness survey across the weldments and transverse weld tensile *** and dissimilar metal weldments responded to both the post weld ageing treatment. After post weld aging, increase in yield strength, UTS and slight reduction in % elongation of similar and dissimilar metal were observed. The observed tensile properties were correlated with microstructure and hardness distribution across the welds.

关键词： maraging steel(250) 13-8 mo stainless steel mechanical properties microstructure

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