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Predicting the strength properties of slurry infiltrated fibrous concrete using artificial neural network

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Frontiers of Structural and Civil Engineering 2018年第4期12卷 490-503页

作者： T.chandra sekhara REDDY Civil Engineering G.P.R.Engineering CollegeKurnool 518002Andhra PradeshIndia

This paper is aimed at adapting Artificial Neural Networks (ANN) to predict the strength properties of SIFCON containing different minerals admixture. The investigations were done on 84 SIFCON mixes, and specimens were cast and tested after 28 days curing. The obtained experimental data are trained using ANN which consists of 4 input parameters like Percentage of fiber (PF), Aspect Ratio (AR), Type of admixture (TA) and Percentage of admixture (PA). The corresponding output parameters are compressive strength, tensile strength and flexural strength. The predicted values obtained using ANN show a good correlation between the experimental data. The performance of the 4-14-3 architecture was better than other architectures. It is concluded that ANN is a highly powerful tool suitable for assessing the strength characteristics of SIFCON.

关键词： artificial neural networks root mean square error SIFCON silica fume metakaolin steel fiber Experimental data Steel fibers Artificial neural networks metakaolin Mean square error strength property FIBER-REINFORCED CONCRETE Additives Silica fume Root mean square

Improvising the Self-Healing Capabilities of Concrete Using Different Pozzolanic Materials and Crystalline Admixtures

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Journal of Wuhan University of Technology(Materials Science) 2022年第3期37卷 429-439页

作者： A Ravitheja T chandra sekhara Reddy C Sashidhar SVR Engineering College AyyalurNandyalKurnoolAndhra PradeshIndia Civil Engineering G Pulla Reddy Engineering CollegeKurnoolAPIndia Jawaharlal Nehru Technological University AnantapurIndia

To analyse the self-healing capacities in terms of mechanical performance of the pozzolanic materials,such as,fly ash,metakaolin and silica fume and crystalline ***-cracked concrete cubes with about 0.05 mm width were exposed to four different environmental conditions at different exposure times in order to determine the effect of temperature and water availability on the self-healing *** the exposure,the control and tested concrete cubes were evaluated for regained strength,void reduction,corrosion inhibition,damp proofing,relative impermeability and *** samples with SF10CA have better cementitious filling and low percentage of voids and water absorption.

关键词： crystalline admixtures pozzolanic materials self-healing

ROBUST HIGH ORDER CONVERGENCE OF AN OVERLAPPING SCHWARZ METHOD FOR SINGULARLY PERTURBED SEMILINEAR REACTION-DIFFUSION PROBLEMS

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Journal of Computational Mathematics 2013年第5期31卷 509-521页

作者： S. chandra sekhara Ra~ Sunil Kumar Department of Mathematics Indian Institute of Technology Delhi Hauz khas New Delhi-110016 India

In this article we propose an overlapping Schwarz domain decomposition method for solving a singularly perturbed semilinear reaction-diffusion problem. The solution to this problem exhibits boundary layers of width O（√ε ln（1/√ε）） at both ends of the domain due to the presence of singular perturbation parameter ε. The method splits the domain into three overlapping subdomains, and uses the Numerov or Hermite scheme with a uniform mesh on two boundary layer subdomains and a hybrid scheme with a uniform mesh on the interior subdomain. The numerical approximations obtained from this method are proved to be almost fourth order uniformly convergent （in the maximum norm） with respect to the singular perturbation parameter. Furthermore, it is proved that, for small ε, one iteration is sufficient to achieve almost fourth order uniform convergence. Numerical experiments are given to illustrate the theoretical order of convergence established for the method.

关键词： Singular perturbation Semilinear reaction-diffusion Overlapping Schwarzmethod Robust convergence Numerov scheme.

Self-Healing Concrete with Crystalline Admixture——A Review

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Journal of Wuhan University of Technology(Materials Science) 2019年第5期34卷 1143-1154页

作者： A Ravitheja Dr T chandra sekhara Reddy Dr C Sashidhar JNTU College of Engineering AnantapurAPIndia Civil Engineering GPR Engineering CollegeKurnoolAPIndia Civil Engineering JNTU College of EngineeringAnantapurAPIndia

The scope of the present paper is to understand the effects of crystalline admixture on the selfhealing capacity of the cementitious composites. Previous studies were examined and a conclusion was drawn to the effect that different additives to crystalline admixture tend to improve self-healing of concrete for larger cracks. It is recommended that initial treatment with chemical admixture can stimulate and heal further cracks and it has the better repeatability trend in mixing with the concretes and mechanical recovery is possible even under repetitive preloading. Effective self-healing with chemical admixtures even under open-air exposure, leads to study the importance of a service ability design parameter including the maximum allowable crack width by repeatability analysis as a function of the exposure with the concept of sealable crack width.

关键词： crystalline admixture permeability reducer admixture cracking

Observation of free oscillations after the 2010 Chile and 2011 Japan earthquakes by superconducting gravimeter in Kutch,Gujarat,India

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Geodesy and Geodynamics 2023年第1期14卷 52-64页

作者： chandra Sekhar Pedapudi Madhusudhana rao Katlamudi Severine Rosat Institute of Seismological Research GandhinagarGujaratIndia Department of Earth Sciences Gujarat UniversityAhmedabadGujaratIndia Institut Terre et Environnement de Strasbourg CNRS UMR 7063StrasbourgFrance

In this paper,we present observations of free oscillations of the Earth after major earthquakes in Chile(February 27,2010,Mw8.8)and Japan(March 11,2011,Mw9.1)using data from the dual-sphere superconducting gravimeter(SG-055),installed at Badargadh(23°0.47 N,70°0.62 E),Kutch,Gujarat,India in March *** see the noise characteristics,we calculated the power spectral density of the gravity time series of 5 quiet days in the frequency band 0.05-20 mHz using the new low noise model(NLNM)as a *** compared the noise level of the Badargadh site to other SG sites around the *** shows that the Badargadh SG is in a low noise *** find that the noise increases at frequencies below 1 *** a characteristic is also observed in Djougou(Afrique,Benin)and Strasbourg(France).Using theoretical tides for Gujarat,we estimated a scale factor of about-814 nm/s~2/V for Gravl(lowersphere)and about-775 nm/s~2/V for Grav2(upper-sphere).We corrected the influence of atmospheric pressure from the one-second gravity data before switching to the frequency *** extracted a total of 53 Earth’s Free Oscillations(EFO)modes during the earthquake in Japan and about 47 EFO modes during the earthquake in *** are able to extract the lowest0S2spheroidal mode(0.30945 mHz or54 min)and0S0radial mode(0.81439 mHz or 20 min).The longer time series shows individual0S2singlets and0S3(0.46855 mHz)singlets due to the Coriolis splitting *** cross-referenced the frequencies of these modes using the PREM model and previous global *** correlation coefficient between the observed and the PREM model for these two events are 0.999 for Japan earthquake and 0.993 for Chile *** validates the quality of the data useful for low-frequency studies in *** also calculated the relative deviations of our observed fundamental modes with previously determined observed and theoretical *** found that the relative deviations of our observed free oscillations

关键词： Superconducting gravity data Free oscillations PREM model

Need for operational simplicity and timely disbursal of benefits—a qualitative exploration of the implementation of a direct benefit transfer scheme for persons with tuberculosis in India

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Infectious Diseases of Poverty 2024年第3期13卷 58-72页

作者： Malu Mohan Jeromie W.V.Thangaraj Sumit Pandey G.Sri Lakshmi Priya Sivavallinathan Arunachalam Rahul Sharma Hemant Deepak Shewade B.Aishwarya K.Afeeq Afsana Khatoon B.Gokulvijay Gude Sireesha Kavita chandra S.Nandhakumar Prince Samuel C.Nanditha Viswanathan Devika Shanmugasundaram Raghuram rao Manoj V.Murhekar Kathiresan Jeyashree Indian Council of Medical Research-National Institute of Epidemiology R-127TNHBAyapakkamChennaiTamil Nadu 600077India TB Support Network WHO Country Office for IndiaNew DelhiIndia Central Tuberculosis Division Government of IndiaNew DelhiIndia

Background Ni-kshay Poshan Yojana(NPY)is a direct benefit transfer scheme of the Government of India introduced in 2018 to support the additional nutritional requirements of persons with TB(PwTB).Our recent nationwide evaluation of implementation and utilization of NPY using programmatic data of PwTB from nine randomly selected Indian states,reported a 70%coverage and high median delay in benefit *** undertook a qualitative study between January and July 2023,to understand the detailed implementation process of NPY and explore the enablers and barriers to effective implementation and utilization of the NPY *** We followed a grounded theory approach to inductively develop theoretical explanations for social phenomena through data generated from multiple *** conducted 36 in-depth interviews of national,district and field-level staff of the National Tuberculosis Elimination Programme(NTEP)and NPY beneficiaries from 30 districts across nine states of India,selected using theoretical *** analytical framework developed through inductive coding of a set of six interviews,guided the coding of the subsequent *** and themes emerged through constant comparison and the data collection continued until theoretical *** Stakeholders perceived NPY as a beneficial *** political commitment from the state administration,mainstreaming of NTEP work with the district public healthcare delivery system,availability of good geographic and internet connectivity and state-specific grievance redressal mechanisms and innovations were identified as enablers of ***,the complex,multi-level benefit approval process,difficulties in accessing banking services,perceived inadequacy of benefits and overworked human resources in the NTEP were identified as barriers to implementation and *** The optimal utilization of NPY is enabled by strong political commitment and challenged by its length

关键词： National Tuberculosis Elimination Programme Nutritional status Direct benefit transfer Implementation Cash transfer scheme Grounded theory India

Influence of local stiffeners and cutout shapes on the vibration and stability characteristics of quasi-isotropic laminates under hygro-thermo-mechanical loadings

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Defence Technology（防务技术） 2022年第12期18卷 2107-2124页

作者： T.Rajanna K.S.Subash chandra K.Venkata rao Department of Civil Engineering B.M.S College of EngineeringBengaluru560019India Research Scholar B.M.S College of EngineeringBengaluru560019India Department of Mechanical Engineering B.M.S Evening College of EngineeringBengaluru560019India Department of Mechanical Engineering Government PolytechnicBagepalli561207India

The perforated stiffened panel is generally found as a sub-component of sophisticated *** fundamental purpose of this panel is to withstand against buckling under complicated loading and environmental ***,an accurate knowledge of critical buckling behaviour of stiffened panels is very much essential for a reliable and lightweight structural *** this paper,the focus is on quasi-laminated panels with different cutout shapes of various sizes and their responses to hygrothermal environments under nonlinearly varying edge loads and is compared with the locally stiffened *** this,the modelling of the panel and stiffener is done by adopting nine-noded heterosis plate elements and three noded beam elements *** stiffener formulation is suitably modified in order to take the torsional effect also into consideration along with the effect of shear ***,the plate and the stiffener elements are treated separately,and then the displacement compatibility is maintained between them by using the transformation *** a given loading and geometric discontinuity,the stress distribution within the perforated panel is highly non-uniform in nature and hence a dynamic approach has been used to calculate buckling loads by adopting two sets of boundary conditions,one set for pre-buckling stress analysis and the second set for buckling *** different quasi-isotropic stacking sequences are deliberated in this work by varying different ply-orientation in each *** study also addresses the effect of various parameters such as nonlinear loads,hygro-thermal loads,cutout size and shapes,position of cutout,stiffener parameters,stacking sequences,thickness of plate and boundary conditions.

关键词： Locally stiffened panels Buckling Vibration Cutouts Heterosis Hygrothermal environment

Cu–Co–O nano-catalysts as a burn rate modifier for composite solid propellants

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Defence Technology（防务技术） 2016年第4期12卷 297-304页

作者： D. Chaitanya Kumar rao Narendra YADAV Puran chandra JOSHI Space Engineering and Rocketry Birla Institute of Technology Mesra Ranchi 835215 India

Nano-catalysts containing copper–cobalt oxides(Cu–Co–O) have been synthesized by the citric acid(CA) complexing method. Copper(II) nitrate and Cobalt(II) nitrate were employed in different molar ratios as the starting reactants to prepare three types of nano-catalysts. Well crystalline nano-catalysts were produced after a period of 3 hours by the calcination of CA–Cu–Co–O precursors at 550 °C. The phase morphologies and crystal composition of synthesized nano-catalysts were examined using Scanning Electron Microscope(SEM), Energy Dispersive Spectroscopy(EDS) and Fourier Transform Infrared Spectroscopy(FTIR) methods. The particle size of nano-catalysts was observed in the range of 90 nm–200 nm. The prepared nano-catalysts were used to formulate propellant samples of various compositions which showed high reactivity toward the combustion of HTPB/AP-based composite solid propellants. The catalytic effects on the decomposition of propellant samples were found to be significant at higher temperatures. The combustion characteristics of composite solid propellants were significantly improved by the incorporation of nano-catalysts. Out of the three catalysts studied in the present work, Cu Co-I was found to be the better catalyst in regard to thermal decomposition and burning nature of composite solid propellants. The improved performance of composite solid propellant can be attributed to the high crystallinity, low agglomeration and lowering the decomposition temperature of oxidizer by the addition of Cu Co-I nano-catalyst.

关键词： Metal oxides Nano-catalysts Solid propellant Burn rate Surface morphology Thermal analysis

Morpho-anatomical and physicochemical studies of Fumaria indica(Hausskn.)Pugsley

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Asian Pacific Journal of Tropical Biomedicine 2012年第10期2卷 830-834页

作者： Prakash chandra Gupta Ch V rao University Institute of Pharmacy Chhatrapati Shahu Ji Maharaj University National Botanical Research Institute

Objective:To study morpho-anatomical characters and physicochemical analysis of Fumaria indica(***)(Hausskn.)Pugsley,(Fumariaceae),an important medicinal plant used extensively for treating a variety of ailments in various system of indigenous ***:Evaluation of the different parts of the plant was carried out to determine the morphoanatomical,physicochemical,phytochemical and HPTLC fingerprinting profile of *** and other WHO recommended methods were performed for ***:Morphoanatomical studies showed compound and pinnatifid leaf,4 to 6 cm in length,linear and oblong in shape and anomocytic arrangement of stomata,thin walled parenchymatous cells,scattered,sclerenchymatous,capped vascular bundles and radiating medullary *** studies showed foreign matter 0.2%,loss on drying 6.8%,total ash 16.77%,alcohol and water soluble extractives 8.92%and 20.26%,respectively,sugar 17.75%,starch 22.97%and tannins 2.37%.Phytochemical evaluation revealed the presence of carbohydrate,alkaloids,flavonoids,saponins,tannins and *** layer chromatography was carried out with different solvents and the best solvent system was chloroform and methanol in 80:20 ratio and revealed 12 spots with different R_f value under UV light 366λ.Conclusions:The results of the study can serve as a valuable source of information and provide suitable standards for identification of this plant material for future investigations and applications.

关键词： Morpho-anatomy Transverse sections HPTLC Stomata Xylem Physicochemical