MHD non similar flow and heat transfer with an exponentially decreasing velocity distribution

K. R. Jayakumar,A. T. Eswara 장전수학회 2014 Proceedings of the Jangjeon mathematical society Vol.17 No.4

MHD non similar flow and heat transfer with an exponentially decreasing velocity distribution

Neutral beam injector system for Steady State Tokamak -1

S. K. Mattoo,A.K. Chakraborty,B. Prajapati,BVSNNP Sridhar,C. Rotti,Ch. Chakrapani,G. Patel,M. Bandyopadhyay,M.J. Singh,M.R. Jana,N.P. Singh,P. Bharati,P.J. Patel,P.K. Jayakumar,R. Onali,S. Ramababu,S. 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.49 No.III

This paper discusses the experimental results obtained from the various components developed for a 1.7 MW neutral beam injector (NBI). Several technologies related to fabrication of back plate, extractor grids, high-current filament feedthru’s, heat-transfer elements, ceramic insulators, cryopumps, rectangular vessels and power supplies have been developed in collaboration with the Indian industry. Control experiments on the prototype plasma box are described.

Hot tensile behavior of SiC-, NbC-, and MgO-reinforced LM25 metal matrix composites for high-temperature applications

Jayakumar T.,Annamalai K. 한국세라믹학회 2023 한국세라믹학회지 Vol.60 No.2

The main aim of this research was to investigate the mechanical behavior of aluminum (LM25) alloy hybrid metal matrix composites for high-temperature applications. The L25 alloy is hybrid reinforced with varying silicon carbide (SiC), niobium carbide (NbC), and magnesium oxide (MgO) nanoparticle compositions. Hybrid particle-reinforced composites are manufactured by means of a liquid manufacturing technique. The hot tensile behavior of the LM25 matrix and hybrid composites was examined under the temperature condition 30 °C–400 °C as per ASTM B557 and ASTM E8M standards using a hot tensile test rig. In addition, the surface morphology of the LM25 alloy and SiC-, NbC-, and MgO-reinforced composites was investigated using scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX). The results of the surface morphology investigation of the composites revealed that the SiC, NbC, and MgO particles were homogenously scattered within the matrix and revealed clearer interface bonding. In tensile test, the LM25 alloy/ 3wt% SiC, NbC, and MgO (LMSMN-3) composite showed a yield and tensile strength around 230.82 MPa and 251.71 MPa, which was 25% larger than the LM25 alloy materials, whereas LM25 alloy/1wt% SiC, NbC, and MgO (LMSMN-1) and LM25 alloy/2wt% SiC, NbC, and MgO (LMSMN-2) composites showed a yield and tensile strength of 176.45 MPa, 203.71 MPa,192 MPa, and 211.32 MPa, respectively, which was 23% and 16.75% higher than the LM25 alloy under room temperature condition. Also, at elevated temperatures such as 200℃ and 400℃, the LMSMN-3 composite exhibited a maximum increase in the tensile properties, i.e., 48.28% at 200℃ and of 61.12% at 400℃.

SOME GENERALIZATIONS OF LOGISTIC DISTRIBUTION AND THEIR PROPERTIES

Mathew, Thomas,Jayakumar, K. The Korean Statistical Society 2007 Journal of the Korean Statistical Society Vol.36 No.1

The logistic distribution is generalized using the Marshall-Olkin scheme and its generalization. Some properties are studied. First order autoregressive time series model with Marshall-Olkin semi-logistic distribution as marginal is developed and studied.

Differential Response of Azolla microphylla Kaulf . and Azolla filiculoides Lam . to Sodium Fluoride

(M . Eyini),(K . Sujanandini),(C . Pothiraj),(M . Jayakumar),(Kil Bong Seop) 한국식물학회 1999 Journal of Plant Biology Vol.42 No.4

Some Generalizations of Logistic Distribution and Their Properties

Thomas Mathew,K. Jayakumar 한국통계학회 2007 Journal of the Korean Statistical Society Vol.36 No.1

The logistic distribution is generalized using the Marshall-Olkin schemeand its generalization. Some properties are studied. First order autore-gressive time series model with Marshall-Olkin semi-logistic distribution asmarginal is developed and studied.AMS 2000 subject classications.Primary 62E10; Secondary 60E05.Keywords.Autoregressive processes, hazard rate, semi-logistic distribution, stationarity.1. IntroductionLogistic distribution has attracted the attention of many researchers due tothe application of this distribution in various elds. Glasbey (1979) applied thegeneralized logistic curve to the weight gain analysis of Ayshire steer calves,which were recorded weekly from birth to slaughter at 880 ponds. Oliver (1982)applied the logistic curve to human population. Wijesinhaet al.(1983) appliedthe polychotomous logistic regression model to large data set of patients wherethere were many distinct diagnostic categories. Johnson (1985) applied logisticregression to estimate the survival time of diagnosed leukemia patients. Morgan(1985) proposed and applied the cubic logistic model to quantal assay data.By various methods new parameters can be introduced to expand families ofdistributions. Introduction of a scale parameter leads to accelerate life modeland taking powers of a survival function introduces a parameter that leads toproportional hazards model. Marshall and Olkin (1997) introduced a new methodof adding a parameter to expand families of distribution. In particular, startingReceived February 2006; accepted October 2006.1Corresponding author. Department of Statistics, M.D. College, Pazhanji-680542, Thrissurdistrict, Kerala, India (e-mail: ttmathew@redimail.com)

Exploring the relationship between TIG welding current and AA5754-H111 joint characteristics

G. Tamil Kumaran,K.S. Jayakumar 한양대학교 청정에너지연구소 2023 Journal of Ceramic Processing Research Vol.24 No.5

This study focused on the effects of pulse current factors, such as peak current, base current, pulse frequency, and pulse length,on the mechanical and metallurgical characteristics of AA5754-H111 steel during gas tungsten arc welding. A total of eighteenconnections were created by correcting the above changes. The purpose of the current research is to examine the mechanicaland microstructural characteristics of welded joints. The optical microscope and SEM analysis were used to carry out themetallurgical characterization. The different types of welding parameter used and evaluated all the welded samples. Thecombination of 160A peak current, 75 Hz pulse frequency, and a 42% duration pulse results in the welded samples' superiormechanical properties as compared to other input welding conditions. These joints have advantages such as consistentlydistributed deposits, better fusion zone hardness, and increased grain quality in the weld zone. These characteristics assist toenhance the tensile characteristics present in joints.

Modification of pharmacokinetics of norfloxacin following oral administration of curcumin in rabbits

B. H. Pavithra,K. Jayakumar,N. Prakash 대한수의학회 2009 JOURNAL OF VETERINARY SCIENCE Vol.10 No.4

Investigation was carried out in adult New Zealand white rabbits to study the influence of curcumin pre-treatment on pharmacokinetic disposition of norfloxacin following single oral administration. Sixteen rabbits were divided into two groups of eight each consisting of either sex. Animals in group-I were administered norfloxacin (100 mg/kg body weight p.o), while animals in group-II received similar dose of norfloxacin after pre-treatment with curcumin (60 mg/kg body weight per day, 3 days, p.o). Blood samples were drawn from the marginal ear vein into heparin-coated vials at 0 (zero time), 5, 10, 15, 30 min and 1, 2, 4, 6, 12 and 24 h post-treatment. Plasma norfloxacin concentrations were determined by high performance liquid chromatography. The plasma concentration-time profile of norfloxacin was adequately described by a one-compartment open model. The pharmacokinetic data revealed that curcumin-treated animals had significantly (p ≤ 0.05) higher area under the plasma concentrationtime curve and area under the first moment of plasma drug concentration-time curve. Prior treatment of curcumin significantly (p ≤ 0.05) increased elimination half-life and volume of distribution of norfloxacin. Further treatment with curcumin reduced loading and maintenance doses by 26% and 24% respectively.

Assessment of environmental flows using hydrological methods for Krishna River, India

Uday Kumar, A.,Jayakumar, K.V. Techno-Press 2018 Advances in environmental research Vol.7 No.3

Krishna River is significantly affected due to Srisailam dam from past 30 years. The impact of this hydraulic structure drastically reduced the minimum flow regime on the downstream, which made the river nearing to decaying stage. In the present paper, Environmental Flow called minimum flow values released for the dam are estimated with the help of three hydrological methods viz., Range of variability Approach (RVA), Desktop Reserve Model (DRM), and Global Environmental Flow Calculator (GEFC). DRM method suggested considering the intermediate values obtained from among the three methods to preserve the ecosystem on the downstream of the river, which amounts to an average annual allocation of 9378 Million Cubic Meter (MCM) which is equal to 23.11% of mean annual flow (MAF). In this regard GEFC and RVA methods accounted for 22% and 31.04% of MAF respectively. The results indicate that current reservoir operation policy is causing a severe hydrological alteration in the high flow season especially in the month of July. The study concluded that in the case of non-availability of environmental information, hydrological indicators can be used to provide the basic assessment of environmental flow requirements. It is inferred from the results obtained from the study, that the new reservoir operations can fulfil human water needs without disturbing Environmental Flow Requirements.

Carbohydrate-Based Nanogels as Drug and Gene Delivery Systems

Uthaman, S.,Maya, S.,Jayakumar, R.,Cho, C.-S.,Park, I.-K. American Scientific Publishers 2014 Journal of Nanoscience and Nanotechnology Vol.14 No.1

Nanogels are hydrogels with nanometer-scale three-dimensional networks of physically or chemically cross-linked chains. Nanogels have attracted much interest in recent years for various biomedical applications such as drug delivery systems and bioimaging owing to their specific properties of size tunability and intrinsic hydrophilic surfaces. Nanogels are generally classified either as natural polymer-based or synthetic polymer-based nanogels. Natural polymer-based nanogels are considered better candidates for drug delivery than synthetic polymer-based nanogels. This review summarizes the role of natural polymer-based nanogels, especially carbohydrate-based nanogels as drug and gene delivery systems.