Recent Trends in Advanced Materials

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Authors: R. Venkatachalam, S. Balasivanandha Prabu
Abstract: The main aim of this work is to identify the natural frequency of mild steel sandwich shaft disc system. An experimental evaluation is completed to evaluate the natural frequency and damping response of mild steel sandwich shaft disc system using Lab VIEW 8.5 software and National Instrument’s data acquisition (DAQ) system. The validation of the experimental results carried out using ANSYS 13.0, a finite element analysis software package. In addition, the effect of shaft thickness, disc thickness, shaft length variation, second, third, four and five systems also studied. The outcome of the results show that the increase in the parameter values have significant effect in the vibration responses of the mild steel sandwich shaft disc system which provide very much helpful information for the designers and researchers.
Authors: Aravind Naga Revuru, Nagarajan Padmavathy, Angappan Sheela, Swamiappan Sasikumar
Abstract: The major cause of surface and ground water contamination is due to effluent from dyeing industries. The discharged effluent chemicals inhibit light penetration into water bodies and some are considered to be carcinogenic. In this study, the photocatalytic decomposition of the synthetic dye, methylene blue was investigated in the presence of activated TiO2. The TiO2 sample was characterized by using XRD to analyze the presence of anatase and rutile phases. The dye degradation was monitored as a change in absorbance by UV-Visible spectrophotometer. The contributing factors towards dye degradation include both the dye concentration as well as the quantity of TiO2 used. Different quantities of TiO2 in anatase phase was taken and activated under UV radiation for 15 min. and subsequently coated on to TLC plates using 5% polyvinyl alcohol as a binding agent. This photocatalytic plate was kept in the methylene blue dye solution and exposed to sunlight. The results shows that 57% of the 30ppm methylene blue dye gets degraded within 75min., when exposed to UV activated TiO2 in presence of natural sunlight.
Authors: Poonam R. Inamdar, Jyotsna Hazarika, T.B. Sridharan, A. Sheela
Abstract: Since the discovery of cisplatin, transitional metal complexes have been proven to be potent DNA intercalating agents. As zinc being an active core of binding site of some metalloenzymes, the synthesis of structurally similar zinc (II) complexes is on the offing. They are found to be potent DNA intercalating and cleaving agents. Thus, the current study is focused on synthesis of zinc (II) complexes using amino acid / schiff bases as ligands. The complexes are characterized by FTIR, UV-Visible and mass spectral studies and assessed for their DNA binding study using λ DNA by Gel electrophoresis.
Authors: S. Ershadul Haque, B. Ramdas, A. Sheela
Abstract: Nano CdS has been prepared by solid state method at room temperature in the absence of any surfactants or dopants. It is characterized by powder X-ray diffraction, scanning electron microscopy (SEM) and diffuse reflectance spectroscopic techniques. It shows cubic structure with the particle size ranging about 20nm. It also exhibits a strong photocatalytic activity for the decomposition of methyl orange (MO) and rhodamine B (RB) under UV and sunlight irradiation. The result shows that CdS exerts greater photocatalytic activity for MO (83%) and RB (73%) under sunlight than UV light.
Authors: Madhvesh Pathak, Blassan Samuel, Kiran Tummalapalli, Prasanth Vuppalapati Giri, Rakesh Bohra, Kap Jin Kim
Abstract: Titanium(IV) complexes of the type [(acac)2Ti(O-G-O] and [(acac)2Ti(OCH2CH2SH)2] {where G = (CH2)2, CH2CH(CH3), CH2CH(C2H5), CH(CH3)CH(CH3) have been synthesized in high yield by the interaction of the precursor [(acac)2Ti( OR)2] {where R = Pri , Et} with a variety of glycols and thioglycols in 1:1 and 1:2 molar ratios in refluxing benzene under anhydrous condition yield heteroleptic derivatives. On the basis of physico-chemical analyses, a cis-octahedral environment around Ti (IV) is proposed.
Authors: Madhvesh Pathak, Blassan Samuel, Kiran Tummalapalli, Prasanth Vuppalapati Giri, Sivasankar Koppala, Rakesh Bohra, Kap Jin Kim
Abstract: Novel structural arrangements for alkoxyalkanol modified titanium tetraisopropoxide [(Ti(OPri)4, TPT] were obtained from stoichiometric reactions between TPT and alkoxyalkanols {HOCH2CH2OR,where R= Me, Et}. All the 1:1, 1:2, 1:3 and 1:4 reactions in refluxing benzene form mononuclear species [(OPri)4-nTi(OC2H4OR)n]. All these compounds can be purified by distillation under reduced pressure. On the basis of IR and NMR (1H &13C) spectral studies all the mononuclear derivatives have been obtained in tetrahedral geometry around titanium atom.
Authors: K. Ghosh, Y. Naresh, N. Srichakradhar Reddy
Abstract: In this paper, we present theoretical model and computations for tuning the photoluminescence (PL) emission of InAs/GaAs quantum dots at 1.3 -1.55 μm by optimizing its height and base dimensions through quantum mechanical concepts. Simulation on the annealing induced compositional change in the QDs was carried out using Fick’s diffusion model. Results from our computation illustrated that lower base size of 10 nm and larger height QDs of 5.1 nm can be effectively utilized for extending the PL emission to longer wavelengths with minimal blue-shift on annealing. This highlights the potential of our model and computation to assist in precisely engineering the optical properties of QD materials for specific device applications.
Authors: Mayank Chakraverty, Harish M. Kittur
Abstract: High gate leakage current, as a central problem, has decelerated the downscaling of minimum feature size of the field effect transistors In this paper, a combination of density functional theory and non equilibrium Green’s function formalism has been applied to the atomic scale calculation of the tunnel currents through CeO2, Y2O3, TiO2 and Al2O3 dielectrics in MOSFETs. The tunnel currents for different bias voltages applied to Si/Insulator/Si systems have been obtained along with tunnel conductance v/s bias voltage plots for each system. The results are in agreement to the use of high dielectric constant materials as gate dielectric so as to enable further downscaling of MOSFETs with reduced gate leakage currents thereby enabling ultra large scale integration. When used as dielectric, TiO2 exhibits extremely low tunnel currents followed by Y2O3 while CeO2 and Al2O3 exhibit high tunnel currents through them at certain bias voltages.
Authors: S. Santhosh, S. Balasivanandha Prabu
Abstract: This study presents wet chemical reaction synthesis of nano Hydroxyapatite (HA) powder from seashells and the use of HA powder for the preparation of a composite coating with polysulfone (PSU), a biocompatible polymer which is electrospun on to Ti-6Al-4V alloy. The XRD/EDX patterns obtained for the synthesized powder showed phase pure hydoxyapatite and the HR-SEM analysis revealed that the HA particles have rod-shaped morphology. The HA powder was reinforced with Polysulfone (PSU) under different concentrations and coated by electro spinning over 2 mm thick sheets of Ti-6Al-4V alloy. The coated titanium sheets were also characterized by HR-SEM.
Authors: Balasubramanian Bhavani, Balakrishnan Naveena, Nagarajan Partha
Abstract: The fibrinolytic enzymes can be used as a potential drug to cure thrombosis diseases. These enzymes can effectively catalyze the degradation of fibrin in blood clot. To develop safe and cheaper fibrinolytic agents, fibrinolytic enzyme was isolated from Streptomyces venezuelae. Strain improvement was employed to increase the production of fibrinolytic enzymes using random mutagenesis (UV and Ethyl methane sulfonate). The mutants obtained were screened based on their fibrinolytic activity and best mutant was selected for further studies. Mutant obtained by Ethyl Methane Sulfonate was able to yield the fibrinolytic activity of 13 FU/mL in growth medium which was higher than wild strain (6 FU/mL). The results indicated that EMS was effective mutagenic agents for strain improvement of Streptomyces venezuelae for enhanced production of fibrinolytic enzyme. The mutant showed improved growth compared to wild strain. The optimal temperature and pH value of this fibrinolytic enzyme were found to be 40 °C and 8.0, respectively. The strain improvement also improves the stability of Streptomyces venezuelae which showed resistance to temperature and pH at higher values. Invitro assays revealed that fibrinolytic enzyme produced by Streptomyces venezuelae could degrade fibrin suggesting that its future application in pharmaceutical industry as thrombolytic agent is highly promising.

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