Decision Making For Vertical Handoff In Heterogeneous Wireless System

V.Sivasankaran,V.Nagarajan,R.Senthil 대한전자공학회 2015 ITC-CSCC :International Technical Conference on Ci Vol.2015 No.6

In upcoming world the communication among heterogeneous wireless networks is a challenging task. Since the access technologies of various networks are different and while interoperable operations, some technical issues may occur. Handoff is an important method can provide solution for making interoperability among heterogeneous networks. Handoff method is purely depends on the attributes of the network such as bandwidth, delay, signal quality, reliability, and energy, access cost and so on. Handoff decision can be obtained by investigating the attribute values and various MADM methods such as SAW, MEW, TOPSIS and GRA are proposed already. In this paper EMADM - [Extended Multiple Attribute Decision Making] approach is proposed to choose the optimized attribute values for decision making using AIS-[Artificial Immune System]. Performance is evaluated by analyzing and comparing the obtained performance metrics with the existing approaches.

Visible upconversion luminescence of Yb co-doped Gd2Zr2O7:Er prepared by a solution combustion reaction

Singh, V.,Rai, V. K.,Gao, H.,Singh, N.,Li, J.,Srivastava, A. K.,Senthil Kumaran, R.,Singh, P. K. Springer Science + Business Media 2016 Journal of materials science Materials in electron Vol.27 No.1

<P>Phosphor powders of Gd2Zr2O7:Er3+ and Gd2Zr2O7:Er3+, Yb3+ have been prepared by the urea combustion route. Phase evolution of the synthesized powder is determined by X-ray diffraction techniques. Near infrared to visible frequency upconversion in the doped/codoped phosphors upon CW diode laser excitation at similar to 978 nm have been studied and an enhancement about similar to 26 and similar to 93 times in the green and red region observed in the Gd2Zr2O7:Er3+, Yb3+ compared to that of the Gd2Zr2O7:Er3+ phosphor. Based upon the ratio of green to red emission band and fluorescence intensity ratio, energy transfer from the Yb3+ to Er3+ ions has been observed to be a dominant process responsible for this enhancement in the visible region.</P>

Genetic Diversity of Indian Jatropha Species as Revealed by Morphological and ISSR Markers

Vijayanand V,Senthil N,Vellaikumar S,Paramathma M 한국작물학회 2009 Journal of crop science and biotechnology Vol.12 No.3

The selection of Jatropha based on morphological information and molecular markers is essential as it is more reliable and consistent. Hence, twelve Jatropha accessions from different geographical areas of India were screened for genetic diversity using 19 morphological traits and 21 ISSR primers. The analysis of morphological traits grouped the accessions into five clusters. The cluster I consisted of J. curcas (CJC 18), J. curcas (CJC 20), J. curcas (CJC 22), J. curcas (CJC21), and J. curcas (CJC 25), and contained the maximum number of accessions; clusters II and IV contained the minimum number of accessions. Among all the characters, the highest range was exhibited by plant height and the least value by the number of branches. The twenty-one ISSR primers generated 156 polymorphic alleles. The average number of ISSR alleles generated was 7.47 per primer. The ISSR primer UBC 884 was highly informative with the maximum of 12 alleles. The 12 genotypes were grouped into eight clusters. The cluster I contained the maximum number of accessions, namely J. curcas (CJC 18), J. curcas (CJC 20), J. curcas (CJC 22), J. curcas (CJC21), and J. curcas (CJC 25). The clusters II, III, IV, V, VI, VII, and VIII (J. tanjorensis, J. gossypiifolia, J. glandulifera, J. podagrica, J. ramanadensis J. villosa, and J. integerrima) contained the minimum number of accessions. Maximum diversity between J. villosa and J. integerrima was noticed and the least diversity between J. curcas (CJC21) and J. curcas (CJC 25) seen because the ISSR markers differentiated the Jatropha accession into a wide genetic diversity as compared to the morphological data. The species-specific diagnostic markers identified in the study such as 1000 bp alleles for J. glandulifera by the primer UBC 826 is suitable for discriminating species of Jatropha, and thus can be used for identifying a Jatropha species from any mixed population comprising other members of the Jatropha complex. The selection of Jatropha based on morphological information and molecular markers is essential as it is more reliable and consistent. Hence, twelve Jatropha accessions from different geographical areas of India were screened for genetic diversity using 19 morphological traits and 21 ISSR primers. The analysis of morphological traits grouped the accessions into five clusters. The cluster I consisted of J. curcas (CJC 18), J. curcas (CJC 20), J. curcas (CJC 22), J. curcas (CJC21), and J. curcas (CJC 25), and contained the maximum number of accessions; clusters II and IV contained the minimum number of accessions. Among all the characters, the highest range was exhibited by plant height and the least value by the number of branches. The twenty-one ISSR primers generated 156 polymorphic alleles. The average number of ISSR alleles generated was 7.47 per primer. The ISSR primer UBC 884 was highly informative with the maximum of 12 alleles. The 12 genotypes were grouped into eight clusters. The cluster I contained the maximum number of accessions, namely J. curcas (CJC 18), J. curcas (CJC 20), J. curcas (CJC 22), J. curcas (CJC21), and J. curcas (CJC 25). The clusters II, III, IV, V, VI, VII, and VIII (J. tanjorensis, J. gossypiifolia, J. glandulifera, J. podagrica, J. ramanadensis J. villosa, and J. integerrima) contained the minimum number of accessions. Maximum diversity between J. villosa and J. integerrima was noticed and the least diversity between J. curcas (CJC21) and J. curcas (CJC 25) seen because the ISSR markers differentiated the Jatropha accession into a wide genetic diversity as compared to the morphological data. The species-specific diagnostic markers identified in the study such as 1000 bp alleles for J. glandulifera by the primer UBC 826 is suitable for discriminating species of Jatropha, and thus can be used for identifying a Jatropha species from any mixed population comprising other members of the Jatropha complex.

Effect of Pulsed Current GTA Welding Parameters on the Fusion Zone Microstructure of AA 6061 Aluminium Alloy

( T. Senthil Kumar ),( V. Balasubramanian ),( S. Babu ),( M. Y. Sanavullah ) 대한금속재료학회 ( 구 대한금속학회 ) 2007 METALS AND MATERIALS International Vol.13 No.4

AA6061 aluminium alloy (Al-Mg-Si alloy) has gathered wide acceptance in the fabrication of food processing equipment, chemical containers, passenger cars, road tankers, and railway transport systems. The preferred process for welding these aluminium alloys is frequently Gas Tungsten Arc (GTA) welding due to its comparatively easy applicability and lower cost. In the case of single pass GTA welding of thinner sections of this alloy, the pulsed current has been found beneficial due to its advantages over the conventional continuous current processes. The use of pulsed current parameters has been found to improve the mechanical properties of the welds compared to those of continuous current welds of this alloy due to grain refinement occurring in the fusion zone. In this investigation, an attempt has been made to develop a mathematical model to predict the fusion zone grain diameter incorporating pulsed current welding parameters. Statistical tools such as design of experiments, analysis of variance, and regression analysis are used to develop the mathematical model. The developed model can be effectively used to predict the fusion grain diameter at a 95 % confidence level for the given pulsed current parameters. The effect of pulsed current GTA welding parameters on the fusion zone grain diameter of AA 6061 aluminium alloy welds is reported in this paper.

Rietveld refinement, microstructure, conductivity and impedance properties of Ba[Zr_0.25Ti_0.75]O_3 ceramic

T. Badapanda,V. Senthil,S.K. Rout,L.S. Cavalcante,A.Z. Simões,T. P. Sinha,S. Panigrahi,M.M. de Jesus,E. Longo,J.A. Varela 한국물리학회 2011 Current Applied Physics Vol.11 No.6

In this work, we report the Rietveld refinement, microstructure, conductivity and impedance properties of Ba[Zr_0.25Ti_0.75]O_3 ceramic synthesized by solid state reaction. This ceramic was characterized by X-ray diffraction, Rietveld refinement, scanning electron microscopy and energy dispersive X-ray spectrometry. Impedance spectroscopy analyses reveals a non-Debye relaxation phenomenon being its relaxation frequency moving toward to positive side with increase of temperature. A significant shift in impedance loss peaks toward higher frequency side indicates conduction in material and favoring the long range motion of mobile charge carriers. The frequency dependent ac conductivity at different temperatures indicates that the conduction process is thermally activated. The variation of dc conductivity exhibited a negative temperature coefficient of resistance behavior. The ac conductivity data are used to evaluate the density of states at Fermi level and activation energy of this ceramic. The dc electrical and thermal conductivities of grain and grain boundary have been discussed.

Effects of Process Parameters on the Mechanical Properties of Glass Fabric Reinforced Polypropylene Composites

S. Suresh,V. S. Senthil Kumar 한국고분자학회 2018 폴리머 Vol.42 No.4

The present study investigates the effects of process parameters such as fabric structure, fabric orientation and compatibilizer concentration on the mechanical properties of fabric reinforced polypropylene composites. Two types of glass fabric reinforced composites with two different stacking sequences were prepared by compressing molding. The composites were prepared with and without compatibilizer for the purpose of analyzing interfacial-bonding. The composites were investigated in terms of tensile, flexural and impact strength for evaluation of the effects of the process parameters. The factorial approach is used to design the experimental layout. The test results revealed that Type-2 fabric reinforced composite in [0-90]4 orientation with 8 wt% compatibilizer possesses better mechanical properties. Tensile, flexural and impact strength were increased by 106%, 235% and 100%, respectively. Analysis of variance was used to identify the most significant factors which would affect the performance of composites. Morphological study explored the presence of strong interfacial-bonding between the materials.

A Political, Economic, Social, Technological, Legal and Environmental (PESTLE) approach for assessment of coastal zone management practice in India

R. Sridhar,V. Sachithanandam,T. Mageswaran,R. Purvaja,R. Ramesh,A. Senthil Vel,E. Thirunavukkarasu 한국행정학회 2016 International Review of Public Administration Vol.21 No.3

This article presents a comprehensive analysis of coastal zone management practice through a political, economic, social, technological, legal and environmental (PESTLE) approach and by reviewing relevant literature. Various geo-morphological features and coastal resources of India and major threats on coastal areas were highlighted. The article also highlights the transition of coastal zone management policies of India and their impacts on the coastal areas and ecosystems. Attempting to cite examples for the eff orts taken for environmental protection from historical past to the recent developing era, the article also describes the present framework and addresses the strengths and challenges and concludes with some suggestions for an eff ective coastal zone management in India.

Experimental investigation of weld characteristics on submerged friction stir welded 6061-T6 aluminum alloy

C. Rathinasuriyan,V. S. Senthil Kumar 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.8

Mechanical properties such as fatigue life, corrosion resistance, brittle fracture, hardness and dimensional stability mainly depend on the residual stresses of the welded sample. The main purpose of the research work is measuring the residual stress at different rotational speeds and water heads and correlates the results with its microhardness and its grain size. In the present study, submerged friction welding was conducted at different rotational speeds of 800, 1000 and 1200 rpm and water heads of 10 and 20 mm, respectively, while the welding speed and axial load were maintained constant. Residual stress was evaluated at the center of the nugget zone on the welded samples using the nondestructive of X-ray diffraction method. Normal friction stir welding (without water head) experiments were carried out later at various rotational speeds of 800, 1000 and 1200 rpm for comparing with the results of the SFS welded samples. The results indicate that the value of d-spacing, lattice parameter and residual stress of submerged friction stir welded sample as higher than that of the normal FS welded sample. The grain size of the SFS welded samples is compared with those of FS welded samples using a scanning electron microscopy. SFSW samples exhibit smaller grain sizes compared to the normal FSW.

Tuning the physical properties of Sb-doped ZnO nanopowders toward elevated photosensing and photocatalytic activity

Kumari S. Senthil,Nirmala W.,Chidhambaram N.,Prabu M.,Ganesh V.,Yahia I. S. 한국세라믹학회 2023 한국세라믹학회지 Vol.60 No.4

This report outlines the photo sensing and photocatalytic properties of the Sb-doped ZnO nanopowders synthesized using the co-precipitation method. According to X-ray diffraction analyses, the produced nanopowders are polycrystalline and devoid of any secondary phase clusters. After antimony was added to the ZnO host matrix, a reduction in crystallite size was noticed. The distinct stretching vibrational modes (Zn–O and Sb–O) present in the produced nanopowders are validated using FTIR measurements. The bandgap shrinkage from 3.21 to 3.16 eV was obtained with the substitution of 5 wt% antimony in the ZnO matrix. In the case of Sb doped nanopowder samples, the reduction in ultraviolet band emission intensity was observed signifying the delayed photo-generated charge carriers recombination, which could favor the photo sensing and photocatalytic activity in ZnO. The photo sensing of the fabricated devices showed maximum responsivity (R), detectivity (D*), and external quantum efficiency (EQE) of 4.78 × 10–2 AW−1, 4.27 × 109 Jones and 11.1%, respectively for the 5% Sb-doped ZnO nanopowder. In addition, the 5% Sb-doped ZnO nanopowder photocatalysts reveal a superior degradation efficiency of 77% among other prepared photocatalysts.

Conducting Copolymer/ZnO Nanocomposite: Synthesis, Characterization, and Its Photocatalytic Activity for the Removal of Pollutants

Sivakumar, K.,Senthil Kumar, V.,Shim, Jae-Jin,Haldorai, Yuvaraj Informa UK (TaylorFrancis) 2014 Synthesis and reactivity in inorganic, metal-organ Vol.44 No.10