Table of Contents - Volume 15 Number 1

Embelin and gliclazide administration to diabetic rats cause a highly significant decline in the blood glycated hemoglobin, serum glucose and nitric oxide activity with a concomitant increase in the serum insulin level. The aim of present work was the development and characterization of self-solid nano-emulsified drug delivery system (SNEDDS) formulation of embelin in combination with gliclazide for the determination of antidiabetic effect in Wistar rats. In this connection, we prepared SNEDDS by using an oil:surfactant mixture ratio of [Capmul^® MCM: Kolliphor^® HS 15: PEG 400 (2:1)] and encapsulated the drug combination in this system. The in-vitro characterization of optimized liquid SNEDDS containing 40% surfactant mixture and 60% oil) was performed and the SNEDDS were found to have particle size of 159.9nm, polydispersity index of 0.289 and zeta potential of -34.35mV. Percentage cumulative release from this formulation was 94.26±3.80% for gliclazide and 90.63±3.67% for embelin in phosphate buffer (pH 7.4) compared to 39.09±1.38% and 34.29±1.20% from plain drug suspension. The embelin (30mg/kg)+gliclazide (10mg/kg) loaded SNEDDS was found to be effective in reversing streptozotocin-induced hyperglycemia as compared to pure drugs in Wistar rats.

Hide Abstract

Microstructure, thermal behavior, wettability and electrochemical corrosion parameters of Sn₈₂Bi₁₅Zn₃, Sn₇₇Bi₁₅Zn₃Sb₅, Sn₇₉Bi₁₅Zn₃Ag₃ and Sn_81.3Bi₁₅Zn₃Cu_0.7 [Jagadeees1] alloys have been studied and analyzed.  The contact angles of used alloys varied from 21° to 31° which is less than 90° (low contact angle).  That is meant, wetting process of these alloys are very favorable and the fluid will spread over a large area of the surface.  Melting temperature values of Sn₈₂Bi₁₅Zn₃, Sn₇₇Bi₁₅Zn₃Sb₅, Sn₇₉Bi₁₅Zn₃Ag₃ and Sn_81.3Bi₁₅Zn₃Cu_0.7 [Jagadeees2] alloys are lower than tin based eutectic solder alloys, (Sn- Zn or Sn- Cu or Sn- Sb), by 11% to 22%.  Scanning electron microscope, x-ray analysis and differential scanning calorimetry graphs show that, the used alloys contained different phases.  Corrosion rate of Sn₈₂Bi₁₅Zn₃ alloy in HCl varied after adding alloying elements.  Sn₇₇Bi₁₅Zn₃Sb₅ alloy has lowest corrosion rate value.

Hide Abstract

(PEO+KNO₃+Nano Al₂O₃) based Composite Polymer Electrolytes (CPE) has been prepared by using solution casting technique. In this technique, Poly (ethylene oxide) (PEO) and KNO₃salt were dissolved separately in methanol and they were mixed together. Nano alumina (Al₂O₃) (particle size ~10nm) was doped to mixed solution and stirred for 24hrs. X-ray diffraction (XRD) technique has been obtained to determine complexation of salt and polymer in composite polymer electrolytes. Ionic and electronic transference numbers of these composite polymer electrolytes has been calculated by using Wagner’s polarization technique. The DC Conductivity of these composite polymer electrolytes has been evaluated in the temperature range of 303-373 K.

Hide Abstract

Ruthenium oxides owing to their high specific capacitance have been widely identified as promising materials for electrochemical charge storage devices. However, high priced ruthenium precursors restrict their commercial usage. Accordingly, numerous explorations investigated the influences on capacitive behavior of ruthenium oxide on blending with varied materials like other metal oxides, activated carbons, conducting polymers, CNTs and functionalized graphene systems as composites. The aim had been to optimize the material cost without compromising with but improving the composite electrochemical performances. The scientific explorations reveal that the overall specific capacitance of composites is a strongly related to the ruthenium oxide (RuO₂) present in the system since it is the main electro-active material providing the Faradaic pseudocapacitances besides the electrical double layer contributions from the base carbon component of the composite. Major progress in the theoretical and practical research and development in this particular field has enviced a large number of research articles and technical reports in the recent past. The current investigations focus on utilizing minimum amount of metal in the composite; upholding the synergistic effect from the metal oxide and the support (carbon materials generally) to obtain better electrochemical signatures. Optimization of important factors leading to reduced nanostructure agglomeration, minimum electrostatic resistance and ultrafast proton/electrons diffusion through the hollow porous structures may ultimately result to the theoretically expected specific capacitance. Nonetheless, to the best of knowledge of the author, there is no systematic review available pertaining to recent advancement of the composites of RuO₂. Thus, this overview categorically narrates recent progresses on the fabrication, performances and achievements of ruthenium oxide composite as electrode material in energy storage applications which will be beneficial especially to the newcomers in this field of research.

Hide Abstract

Thin films of MoO₃ were deposited on quartz glass, Silicon (100) and Indium Tin Oxide (ITO) substrates by dc magnetron sputtering  at two substrate temperatures of 300 K and 600 K and at sputtering pressures of 5 Pa and 10 Pa and at a fixed sputtering power of 50 W.  The deposited films were characterized by  Grazing Incidence X-ray Diffraction (GIXRD), Raman and Optical Transmittance Spectra and Cyclic Voltametry (CV) studies. The GIXRD reveales that the  crystallanity of films starts at low temperature (300 K) and crystallizes in orthorhombic phase. The crystallanity increases with increase of substrate temperature. The Raman spectral studies reveals strong shift in the emission peak position for films deposited at 5 Pa and 300 K,  and there is no significant peaks in case of  films deposited at 10 Pa and 600 K. The optical transmittance of the films  is 78 % for films deposited at 5 Pa and 300 K and is maximum (95 %) when deposited at 600 K.  The transmittance is decreasing to 90 % with increase in sputtering pressure. The absorption edge is shifting towards lower wavelength with increase in substrate temperature due to increase in the reactivity of the ionic species (molybdenum ions and oxygen ions) and shifting towards higher wavelengths with sputtering pressures due to the scattering of atomic species which decreases the reactivity between ionic species.   The average diffusion coefficient (D) of the films deposited at 5 Pa and 300  K is 7x10^-14 cm²/sec and decreasing with increase in substrate temperature of the deposited films. With further increase in the sputtering pressure to 10 Pa and at low temperatures a large increment in the D value was observed (8.2x10^-12 cm²/sec) due to the enhancement in the mobility of the Li⁺ ions through the internal and intra grain boundaries due to low grain size of MoO₃ (8 nm) of the film. The measured thickness of the films by Taly stip profilometer is 3000 Å.

Hide Abstract

Dysprosium substituted Magnesium ferrite weresuccessfully prepared by chemical combustion method. The as synthesized powder was presintered in air at 600⁰C for 1hr and finally sintered at 950⁰C for 1hr. From X-ray powder diffraction pattern of MgDy_0.03Fe_1.97O_4, confirmed formation of single phase cubic spinel structure. The value of crystallite size obtained from X-ray powder diffraction (311) peak , it is found to be 46.38nm.The frequency and temperature variation of dielectric parameters such as real dielectric constant (ε′), complex dielectric constant (ε") and dielectric loss tangent (tanδ) were determined using Hioki LCR - Q meter. The frequency variation of dielectric constant shows a normal dielectric behavior of spinel ferrites. The dielectric loss tangent with frequency shows similar behavior as dielectric constant. The dielectric constant and dielectric loss tangent increases with increase in temperature

Hide Abstract

Films of polyvinyl alcohol (PVA) – polyvinyl pyrrolidone (PVP) blend doped with lead nitrate (Pb(NO₃)₂) were prepared by solution casting method, with doping level (DL) of Pb(NO₃)₂ in PVA – PVP polymeric blend varying from 2.7 up to 50.5 wt%. The prepared films were characterized using UV-Visible spectroscopy, fluorescence (or photo- luminescence) spectroscopy, FTIR and Raman spectroscopy. Parameters like optical band gaps due to indirect allowed transition (IAT) and direct allowed transition (DAT), as well as the activation energy (E_a) for optical transitions are extracted from the UV- Visible (or optical) spectra of these films. Objective of the FTIR, Raman and Fluorescence spectroscopic study is to understand the molecular chemical changes in PVA and PVP caused by the dopant (Pb(NO₃)₂). There is an enhancement of fluorescence intensity at DLs of 2.7 wt%, and at DL 7.6 wt%, the fluorescence intensity decreases (quenching). PVP acts as a capping agent for the dopant species, and is considered to be responsible for changes in fluorescence intensity. Signature of nitrate ion (NO₃^-) vibration is observed at wavenumber 1037 cm^-1 in Raman spectra, and in the FTIR spectra, the NO₃^- vibration is seen at the wavenumber equal to 1380 cm^-1.

Hide Abstract

Aluminum based metal matrix composites are given more attention in fabrication of surface engineering applications due to their excellent mechanical and wear properties. In this study, Friction stir processing (FSP) method was used to fabricate the surface composite with inserting different volume % of ZrO₂ reinforcement particles in the Aluminum 6082 alloy. The hardness and triblogical characteristics of fabricated surface composites and base alloy were investigated. The higher volume content of reinforcement surface revealed higher hardness and higher wear resistance compared to the lower volume content reinforcement surface and base material. The wear worn-out of composite surfaces and base alloy were examined through SEM for understanding the wear mechanisms.

Hide Abstract

In this paper, a comprehensive concept of the effect of new technology on the energy economics of petroleum, gas and petrochemistry is proposed. The roadmap of development, the tools of the main method, elements, the main challenges and weak points are discussed. The treasury of stock exchange allows the energy economics to have a criterion for the policies of the government, a common landscape for the various beneficiaries, reinforcement of the research and development based upon the new technology of the energy sector. Three case studies (national firm of petrochemical industry of Kermanshah, shazand and Tabriz) from ETF in world market is proposed to illustrate the conceptual approach. This article is under the special attention of researcher, deciders and the commission of studies to promote their policies.

Hide Abstract

Pure and Magnesium Nitrate hexahydrate (MgN) doped Barium Nitrate (BaN) crystals were grown by slow evaporation technique. FTIR spectral studies have been carried to identify the presence various functional groups. An FTIR spectrum of grown crystals confirms the presence of ionic bonds in the structure of pure and doped BaN crystals. The influence of MgN doping on FTIR spectra was absorbing frequencies by pure and doped BaN crystals were studied. Thermogravimetric of pure and doped BaN crystals were analysed to characterise thermal stability. Thermal parameters are evaluated using thermogram. The results are presented and discussed in this paper.

Hide Abstract

In this paper, the effect of scan rate on the corrosion parameters and electrochemical behaviour of Retrogression and Re-aging (RRA) heat treatment of 7075 aluminium alloy has been investigated by Potentiodynamic polarization (PD) and electrochemical impedance spectroscopy (EIS) methods. The Potentiodynamic polarization (PD) curves were obtained at various scan rates for aged aluminium alloys in 0.5 M H₂SO₄ solution. The results show that at high scan rates shows unpredicted fluctuation of charging current, whereas at lower scan rates fewer disturbances are observed. The aged samples were chemically and mechanically characterized. It was observed that the RRA at 0.7 h shown improved corrosion property as well as mechanical properties compared to T6 temper. The corrosion properties were confirmed by EIS and polarization experiments.

Hide Abstract

In present experimental study an attempt has been made to investigate the effect of three machine input parameters namely current,voltage and nozzle to plate distance (NPD) on tensile strength of weld bead and weld penetration. Three different levels (current 180, 190, 200 in ampere. Voltage 21, 24, 27 in volt and NPD 12, 16, 20 in mm) have been considered in order to evaluate the effect of these parameters on tensile strength and penetration of weld bead. Taguchi method has been employed  to abate the number of experiments and  analyze  the effect of various parameters. Orthogonal array L9 was used for data optimization. On the basis of experimental data, the mathematical technique  has been developed by using analysis of variance. Results were obtained from each parameter at different levels for tensile strength and weld bead geometry. Based on these results different parameters were identified for maximum tensile strength and maximum weld penetration. Result show that maximum tensile strength was 390.8 Mpa at 200 ampere current, 27 volt and 16 mm NPD where as maximum weld penetration was 3.20 mm at 200 ampere current, 24 volt and 12 mm NPD

Hide Abstract