PRIMORDIAL RADIONUCLIDES DISTRIBUTION AND DOSE EVALUATION IN UDAGAMANDALAM REGION OF NILGIRIS IN INDIA

Manikandan, N. Muguntha,Selvasekarapandian, S.,Sivakumar, R.,Meenakshisundaram, V.,Raghunath, V.M. 대한방사선 방어학회 2001 방사선방어학회지 Vol.26 No.3

The activity concentration of primordial radionuclides i.e., 238U series, 232Th series and 40K, in soil samples collected from Udagamandalam environment, have been measured by employing NaI(Tl) Gamma ray Spectrometer. The absorbed gamma dose rate has also been simultaneously measured by using both Environmental Radiation Dosimeter at each soil sampling location (ambient gamma dose) as well as from the gamma dose derived from the activity concentration of the primordial radionuclides. The results of activity concentration of each radionuclides in soil, absorbed dose rate in air due to soil activity and possible cosmic radiation at each location along with human effective dose equivalent for Udagamandalam environment are presented and discussed.

Influence of plastic viscosity of mix on Self-Compacting Concrete with river and crushed sand

J.S. Kalyana Rama,M.V.N. Sivakumar,K. Sai Kubair,A. Vasan 사단법인 한국계산역학회 2019 Computers and Concrete, An International Journal Vol.23 No.1

In view of the increasing utility of concrete as a construction material, the major challenge is to improve the quality of construction. Nowadays the common problem faced by many of the concrete plants is the shortage of river sand as fine aggregate material. This led to the utilization of locally available materials from quarries as fine aggregate. With the percentage of fines present in Crushed Rock Fines (CRF)or crushed sand is more compared to river sand, it shows a better performance in terms of fresh properties. The present study deals with the formulation of SCC mix design based on the chosen plastic viscosity of the mix and the measured plastic viscosity of cement pastes incorporating supplementary cementitious materials with CRF and river sand as a fine aggregate. Four different combinations including two binary and one ternary mix are adopted for the current study. Influence of plastic viscosity of the mix on the fresh and hardened properties are investigated for SCC mixes with varying water to cement ratios. It is observed that for an increasing plastic viscosity of the mix, slump flow, T500 and J-ring spread increased but V-funnel and L-box decreased. Compressive, split tensile and flexural strengths decreased with the increase in plastic viscosity.

Microwave sintering of iron deficient Ni–Cu–Zn ferrites for multilayer chip inductors

M. Penchal Reddy,W. Madhuri,G. Balakrishnaiah,N. Ramamanohar Reddy,K.V. Sivakumar,V.R.K. Murthy,R. Ramakrishna Reddy 한국물리학회 2011 Current Applied Physics Vol.11 No.2

This study was aimed at the low temperature synthesis of iron deficient samples of Ni―Cu―Zn ferrite using the microwave sintering technique. The samples were sintered at 950 ℃ for 30 min. Microstuctural and structural analyses were carried out using a scanning electron microscope (SEM) and X-ray diffraction (XRD), respectively. The lattice parameter was found to increase with increasing nickel concentration. The porosity calculated using X-ray density and measured density also shows a decreasing behavior with increasing nickel concentration. The variation of saturation magnetization was studied as a function of nickel concentration. All the compositions indicate that they are ferrimagnetic in nature. Initial permeability plotted against temperature at 10 kHz showed a sharp drop at Curie transition temperature and values observed at transition are found to be dependent on the nickel concentration. The dielectric constant, dielectric loss tangent and ac conductivity of all samples were measured at room temperature as a function of frequency. These parameters decrease with increase in frequency for all of the samples. The present ferrites are well suitable for the application in multilayer chip inductor due to its low temperature sinterability, good magnetic properties and low loss at high frequency.

PRIMORDIAL RADIONUCLIDES DISTRIBUTION AND DOSE EVALUATION IN UDAGAMANDALAM REGION OF NILGIRIS IN INDIA

N. Muguntha Manikandan,S. Selvasekarapandian,R. Sivakumar,V. Meenakshisundaram,V.M. Raghunath 대한방사선방어학회 2001 방사선방어학회지 Vol.26 No.3

Durable keratin-based bilayered electrospun mats for wound closure

Singaravelu, Sivakumar,Ramanathan, Giriprasath,Muthukumar, Thangavelu,Raja, M. D.,Nagiah, Naveen,Thyagarajan, Sitalakshmi,Aravinthan, Adithan,P., Gunasekaran,Natarajan, T. S.,V. N. Geetha Selva, Ganga The Royal Society of Chemistry 2016 Journal of Materials Chemistry B Vol.4 No.22

<P>A bilayered nanofibrous scaffold with rapid wound healing properties is found to be suitable for tissue regeneration applications. The objective of this study is to reveal the fabrication of a poly(3-hydroxybutyric acid) (P)-gelatin (G) nanofibrous mat through electrospinning, with a horn keratin-chitosan-based biosheet (KC) as a bilayered nanofibrous scaffold. The mupirocin (D)-loaded horn KC biosheet (KCD) acts as the primary layer over which PG nanofibers were electrospun to act as the secondary layer. It is shown that this engineered bilayered nanofibrous scaffold material (KC-PG) should fulfill the functions of the extracellular matrix (ECM) by elucidating its function<I>in vitro</I>and<I>in vivo</I>. The bilayered nanofibrous scaffold was designed to exhibit improved physiochemical, biological and mechanical properties, with better swelling and porosity for enhanced oxygen permeability, and it also exhibits an acceptable antibacterial property to prevent infection at the wound site. The bilayered nanofibrous scaffold assists in better biocompatibility towards fibroblast and keratinocyte cell lines. The morphology of the nanofibrous scaffold aids increased cell adhesion and proliferation with cell material interactions. This was elucidated with the help of<I>in vitro</I>fluorescence staining against both cell lines. The bilayered KCD-PG nanofibrous scaffold material gives accelerated wound healing efficiency during<I>in vivo</I>wound healing. The results showed the regulation of growth factors with enhanced collagen synthesis, thereby helping in faster wound healing.</P>

Optimization of low temperature hydrogen sensor using nano ceramic-particles for use in hybrid electric vehicles

J. Niresh,N. Archana,S. Neelakrishnan,V. M. Sivakumar,D. S. Dharun 한양대학교 세라믹연구소 2020 Journal of Ceramic Processing Research Vol.21 No.3

Hydrogen sensing in automobile application is the need of the hour as fuel cell based hybrid electric vehicle is developingat a faster pace. Nickel ferrite (NiFe2O4) nanoparticles embedded reduced graphene oxide (rGO) prepared by a facilehydrothermal thermal process was employed as a chemiresistive sensor for the detection of H2 gas. To study themorphological and structural features the synthesized samples were characterized by transmission electron microscopy(TEM), X-Ray diffraction and Raman Spectroscopy. 50 nm cube shaped NiFe2O4 nanoparticles were found to bedistributed on few layered rGO nanosheets. The electrical conductivity of pristine n type NiFe2O4 and NiFe2O4/rGO weretested at various operating temperatures. Hydrogen sensing characteristics were measured by forming a thick film of thesynthesized nanocomposite paste on an alumina substrate. Sensing results showed that NiFe2O4/ 1% rGO showed themaximum response at an optimum temperature of 80 ºC towards 200 ppm of hydrogen gas among four variants. Integration of NiFe2O4 nanoparticles on rGO nanosheets has markedly enhanced the conductivity of the nanocomposite. The sensor showed a lower detection limit of 8 ppm with two linear ranges from 30-90 ppm and 100 to 700 ppm. Furtherthe sensor was tested for its selectivity and stability.

Plastic viscosity based mix design of self-compacting concrete with crushed rock fines

Kalyana Rama J S,Sivakumar M V N,Vasan A,Sai Kubair,Ramachandra Murthy A 사단법인 한국계산역학회 2017 Computers and Concrete, An International Journal Vol.20 No.4

With the increasing demand in the production of concrete, there is a need for adopting a feasible, economical and sustainable technique to fulfill practical requirements. Self-Compacting Concrete (SCC) is one such technique which addresses the concrete industry in providing eco-friendly and cost effective concrete. The objective of the present study is to develop a mix design for SCC with Crushed Rock Fines (CRF) as fine aggregate based on the plastic viscosity of the mix and validate the same for its fresh and hardened properties. Effect of plastic viscosity on the fresh and hardened properties of SCC is also addressed in the present study. SCC mixes are made with binary and ternary blends of Fly Ash (FA) and Ground Granulated Blast Slag (GGBS) with varying percentages as a partial replacement to Ordinary Portland Cement (OPC). The proposed mix design is validated successfully with the experimental investigations. The results obtained, indicated that the fresh properties are best achieved for SCC mix with ternary blend followed by binary blend with GGBS, Fly Ash and mix with pure OPC. It is also observed that the replacement of sand with 100% CRF resulted in a workable and cohesive mix.

Antitumor effect of Careya arborea against Ehrlich ascites carcinoma with reference to lipid peroxidation and enzymatic and non enzymatic antioxidant system in Swiss albino mice

R Sambath Kumar,T Sivakumar,V Senthil,N Venkateswara Murthy,V Balasubramaniam,R Kanaga Sabi,R. Shanmuga Sundram,P Perumal,U K Mazumder,M Gupta 경희대학교 융합한의과학연구소 2008 Oriental Pharmacy and Experimental Medicine Vol.8 No.2

The methanol extract of stem barks of Careya arborea Roxb. (MECA) (Family- Myrtaceae) was evaluated for antitumor activity and antioxidant status against Ehrlich’s Ascites Carcinoma (EAC) bearing Swiss albino mice. After 24 h of tumor inoculation the MECA was administered at the doses of 50, 100 and 200 mg/kg body weight/mice/day for 14 days. After the last dose and 18 h fasting mice were sacrificed. The effect of MECA on the growth of transplantable murine tumor, life span of EAC bearing hosts, hematological profiles, serum and liver biochemical parameters were estimated. The MECA showed significant (P < 0.01) decrease in ascites volume, packed cell volume and viable cell count and prolonged the life span of EAC tumor bearing mice. Hematological profiles reverted to more or less normal levels in extract treated mice. The MECA also produced protective effect by decreasing the activity of serum enzymes, bilirubin and increase the protein and uric acid levels. MECA significantly (P < 0.05) decreased the levels of lipid peroxidation, while significantly (P < 0.05) increased the levels of glutathione content, vitamin C, vitamin E, superoxide dismutase and catalase CAT. The results indicate that MECA exhibited significant antitumor and antioxidant activity in EAC bearing mice. The methanol extract of stem barks of Careya arborea Roxb. (MECA) (Family- Myrtaceae) was evaluated for antitumor activity and antioxidant status against Ehrlich’s Ascites Carcinoma (EAC) bearing Swiss albino mice. After 24 h of tumor inoculation the MECA was administered at the doses of 50, 100 and 200 mg/kg body weight/mice/day for 14 days. After the last dose and 18 h fasting mice were sacrificed. The effect of MECA on the growth of transplantable murine tumor, life span of EAC bearing hosts, hematological profiles, serum and liver biochemical parameters were estimated. The MECA showed significant (P < 0.01) decrease in ascites volume, packed cell volume and viable cell count and prolonged the life span of EAC tumor bearing mice. Hematological profiles reverted to more or less normal levels in extract treated mice. The MECA also produced protective effect by decreasing the activity of serum enzymes, bilirubin and increase the protein and uric acid levels. MECA significantly (P < 0.05) decreased the levels of lipid peroxidation, while significantly (P < 0.05) increased the levels of glutathione content, vitamin C, vitamin E, superoxide dismutase and catalase CAT. The results indicate that MECA exhibited significant antitumor and antioxidant activity in EAC bearing mice.

Influence of coarse aggregate properties on specific fracture energy of steel fiber reinforced self compacting concrete

Raja Rajeshwari, B.,Sivakumar, M.V.N. Techno-Press 2020 Advances in concrete construction Vol.9 No.2

Fracture properties of concrete depend on the mix proportions of the ingredients, specimen shape and size, type of testing method used for the evaluation of fracture properties. Aggregates play a key role for changes in the fracture behaviour of concrete as they constitute about 60-75 % of the total volume of the concrete. The present study deals with the effect of size and quantity of coarse aggregate on the fracture behaviour of steel fibre reinforced self compacting concrete (SFRSCC). Lower coarse aggregate and higher fine aggregate content in SCC results in the stronger interfacial transition zone and a weaker stiffness of concrete compared to vibrated concrete. As the fracture properties depend on the aggregates quantity and size particularly in SCC, three nominal sizes (20 mm, 16 mm and 12.5 mm) and three coarse to fine aggregate proportions (50-50, 45-55, 40-60) were chosen as parameters. Wedge Split Test (WST), a stable test method was adopted to arrive the requisite properties. Specimens without and with guide notch were investigated. The results are indicative of increase in fracture energy with increase in coarse aggregate size and quantity. The splitting force was maximum for specimens with 12.5 mm size which is associated with a brittle failure in the pre-ultimate stage followed by a ductile failure due to the presence of steel fibres in the post-peak stage.

Antitumor effect of Careya arborea against Ehrlich ascites carcinoma with reference to lipid peroxidation and enzymatic and non enzymatic antioxidant system in Swiss albino mice

Kumar, R Sambath,Sivakumar, T,Senthil, V,Murthy, N Venkateswara,Balasubramaniam, V,Sabi, R Kanaga,Sundram, R. Shanmuga,Perumal, P,Mazumder, U K,Gupta, M Kyung Hee Oriental Medicine Research Center 2008 Oriental pharmacy and experimental medicine Vol.8 No.2

The methanol extract of stem barks of Careya arborea Roxb. (MECA) (Family- Myrtaceae) was evaluated for antitumor activity and antioxidant status against Ehrlich's Ascites Carcinoma (EAC) bearing Swiss albino mice. After 24 h of tumor inoculation the MECA was administered at the doses of 50, 100 and 200 mg/kg body weight/mice/day for 14 days. After the last dose and 18 h fasting mice were sacrificed. The effect of MECA on the growth of transplantable murine tumor, life span of EAC bearing hosts, hematological profiles, serum and liver biochemical parameters were estimated. The MECA showed significant (P < 0.01) decrease in ascites volume, packed cell volume and viable cell count and prolonged the life span of EAC tumor bearing mice. Hematological profiles reverted to more or less normal levels in extract treated mice. The MECA also produced protective effect by decreasing the activity of serum enzymes, bilirubin and increase the protein and uric acid levels. MECA significantly (P < 0.05) decreased the levels of lipid peroxidation, while significantly (P < 0.05) increased the levels of glutathione content, vitamin C, vitamin E, superoxide dismutase and catalase CAT. The results indicate that MECA exhibited significant antitumor and antioxidant activity in EAC bearing mice.