Table of Contents - Volume 6 Number 1

The network structure of the polystyrene resin/carbon black (PS/CB) nanocomposites were studied by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), crosslinking density , interparticle distance among conducting sites . Mechanical properties of PS composite filled with different content of CB were investigated and the composite always exhibited higher hardness and elastic modulus than green PS. The thermal stability of nanocomposites was examined by thermal gravimetric analysis. The influences of CB content on the static conductivity, mobility carriers and concentration of charge carriers of the PS/CB nanocomposites were examined. Conductivity – temperature curves shows a positive temperature coefficient of resistance (PTCR) effect. It has been proved that the inclusion of CB into the PS/CB nanocomposites significantly enhanced the PTCR intensity and thermal stability of the nanocomposites. The electromagnetic interference shielding effectiveness (EMI), the dielectric constant, the skin depth, the reflection coefficient and the absorbance coefficient as functions of CB content of composites are investigated. In addition, the EMI, of the nanocomposites were measured and calculated in a frequency range of 1-12 GHz. The results show that PS/CB composites exhibit high EMI in the microwave band at high CB content. The composites studied are found to have a wide range of potential applications for PTCR thermistors and microwave absorber at 12 GHz.

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A new method in selecting the inputs of the neural networks for multivariate time series is proposed. The input and output time series are analyzed and suitable mathematical models are built in the input-output model parametric representation. The inputs to the best input-output models are chosen as the inputs to the neural network model. The estimates from different models are then combined to obtain an unbiased estimate of the output series. The resulting combined neural network model is used in forecasting the bench marking gas furnace multivariate time series. The new developed procedure outperformed previously used forecasting techniques.

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Various compositions of silver conducting glasses [AgI – Ag2O-P2O5-Fe2O3 ] were prepared by melt quenching technique. X-ray diffraction (XRD),Mossbauer effect (ME), infrared (IR), differential thermal analysis (DTA) studies were carried. Dielectric measurements have been carried out on (50-x)P2O5-xAgI-40Ag2O-10Fe2O3 ,[x=0,5,10,15,20,30] glasses from 50 Hz upto 5MHz.The frequency dependence of the total conductivity is nearly constant at the low frequency, identified with the true dc ionic conductivity sdc (0) and at high frequencies an additional term increasing in a power law with exponent s<1 corresponds to translational hopping motion.Effect of frequency and temperature on dielectric constants and dielectric loss is studied. The general behaviour of e?? shows a decrease with increasing frequency following a power relation with exponent m>1 and activation energy values of Wm about 0.042-0.016 eV lower than obtained using dc conductivity.

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The electrochemical behaviour of iron electrode in different concentrations of NaOH solution was studied using cyclic voltammograms and A.C. Impedance techniques. Four anodic peaks (A1-A4) were observed in the anodic scan of cyclic voltammograms where two cathodic peaks (C1 and C2) were observed in the cathodic scan of cyclic voltammograms. The four anodic peaks due to the formation Fe(OH)ads peak (A1), Fe(OH)2, peak (A2), Fe2O3(peak A3) and formation of more stable Fe(III) species (peak A4) and the cathodic scan due to the reduction of species formed on the anodic scan.

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Launch event imposes critical loading conditions on the space flight hardware. Space structures are exposed to different environments and consequently the space vehicle experiences various loading conditions. The random vibration load, which is inputted mechanically and acoustically from rocket engines, is one of the major loads which must be considered in payload flight hardware structures. In this study two different approaches for calculating the frequency response of a small satellite structure under random vibration acceleration loads have been considered. These approaches are based on frequency response analysis using modal effective modes and effective masses related to these modes, and finite element spectrum analysis. The first approach considers the overall behavior of the structure. On the other hand, the second approach reveals the response of the structure on each desired node. The results of the first approach are dependent on the number of selected modes, and effective masses related to the modes. The analyses for small satellites show that the application of superposition technique can result in an appreciable reduction in the calculation time, and helps in finding points on the structure, which show the behavior of the center of gravity during the tests. In addition, it may also be used as approximation for modeling of satellite behavior, treated as concentrated mass, during the quick analyses at the preliminary design, and for the satellite and launcher coupled analyses. The analyses show that the satellite behavior under the effect of local modes can be different. This increases the error in this approach, especially for larger structures, which have structure elements with greater inertial effects and consequently higher local effective masses. This approach also predicts the equivalent static load based on root mean square (rms) calculation of power spectral density response. This paper also considers the influence of effective mode selection criteria on the rms value of the response.

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The interaction of alloys with the ionic components of the electrolyte, in the metallic lattice of alloys, shows that the boundary layer with the changed composition presents, the interdiffusion of its components occurs, and plastic flow of atomic planes appears. The physical mechanism of these phenomena is examined.

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Various compositions of silver-based superionic conducting [AgI – Ag2O-P2O5-Fe2O3 ] glasses were prepared by melt quenching technique. X-ray diffraction (XRD),Mossbauer effect (ME), infrared (IR), differential thermal analysis (DTA) and electrical conductivity studies were carried out to optimize the high ionic conducting composition. Solid-State primary batteries were fabricated using the 20P2O5-30AgI-40Ag2O-10Fe2O3 glass with Ag2S as anode and Ag as cathode of type; ( ( Ag2S + SE ) / solid electrolyte / Ag ). Superionic solid electrolyte glass for rechargeable battery application was performed and characterized at many conditions such as different thichnesses , different pressures , different load resistance , different temperatures , annealing times and different storage times.

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Cr(III) hydrolysis in aqueous solution has been studied theoretically by means of density-functional method (DFT). All possible structures arising from different tautomers have been determined. The solvation energy has been calculated using the UAHF-PCM method. The hydrolysis reaction free energies have been calculated and compared with the available experimental data. The different hydrolysis species have distinct geometries and electronic structures. Improvement of theory level in calculating the electronic energy does not necessarily improve the calculated free energies in aqueous solution since the UAHF-PCM is a simple method that neglects specific interactions with the solvent. Therefore, it is important to have the correct balance between theory level used in the electronic properties calculation especially in the UAHF-PCM method. The PBE/TZVP/UAHF-PCM method has been found to calculate correctly the hydrolysis energies of Cr(III), deviating about 2.7 kcal/mol from experimental values.

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Zinc oxide nanoparticles are fabricated using Ball milling method. For the synthesis of these nanoparticles, 99.9% pure zinc oxide powder is milled for 40 hours. Transmission electron microscopy is employed to study the microstructure of these nanoclusters. It is seen from the transmission electron microscope (TEM) images that the nanoparticles of ZnO are aggregated and form nanoclusters. The diameter of these nanopaticles varies from 5-10 nm, whereas the diameter of these nanoclusters is of the order of several tens of nanometers. The X-ray diffraction technique is used to verify the structure of these synthesized zinc oxide nanoparticles. From the XRD pattern, it is suggested that these nanoparticles are crystalline in nature. The UV visible spectrum shows a broad peak at 380 nm, which is a characteristic of ZnO.

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In the present paper, we have investigated two characteristics of three different wave guides employed in arrayed waveguide grating (AWG) in passive optical networks (PON) where rates of variations are processed. Both the thermal and the spectral effects are taken into account. The waveguides are made of Lithium Niobate, germania-doped silica, and Polymethyl metha acrylate (PMMA) polymer. The thermal and spectral sensitivities of optical devices are also analyzed. In general, both qualitative and quantitative analysis of the temporal and spectral responses of AWG and sensitivity are parametrically processed over wide ranges of the set of affecting parameters.

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In this paper, we present the concept of Problem-Based Learning as a tool of integrating the basic knowledge previously acquired in a chemistry lesson to the mathematical modeling of pH-metrics. In like manner, we consider how to use this technique to bring the knowledge acquired in a calculus lesson into teaching electricity in a chemistry class. It involves some level of brain storming. Here active learning takes place and knowledge gained by students either way through a collaborative learning situation becomes personalized within the group. This underscores the need for the integration of the curricular of some basic concepts in mathematics and the sciences in general from the school level, thus it makes it easier for students in the tertiary educational level to learn higher and applicable concepts. Problem-based learning method then becomes an enviable tool which can be used in teaching both Mathematics and Chemistry at the Secondary and tertiary levels.

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This paper reports on the application of Fourier transform to speckle photography. The simple technique here enables the measurement of the refractive index of a transparent plate. A simple mathematical approach has been applied utilizing the resulting data to estimate the refractive index of the plate.

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A sample of Balanites oil was analyzed by some chromatographic methods. The saponifiable and the unsaponifiable contents of the oil were determined, It was found that the oil contains 84.56% fatty acids and 1.03 % sterols. The percentages of the fatty acids Stearic, Palmitic, Oleic and Linoleic in the oil were found 7.18, 12.50, 30.90, and 34.34% respectively.

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In this work we take into consideration a (2+1)-dimensional higher order Broer-Kaup system. Amodification of homogenous balance method (HB) is suggested to search for periodic solution and solitary wave solution of Broer-kaup system of nonlinear equations.

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The inhibition effect of Acalypha indica L. water extract (AIWE) on mild steel corrosion in 1N phosphoric acid has been studied by mass loss and polarization techniques between 303 K and 333K. The inhibition efficiency increased with increase in concentration of plant extract. The corrosion rate increased with increase in temperature and decreased with increase in concentration of inhibitor compared to blank. The adsorption of inhibitor on mild steel surface has been found to obey Temkin?s adsorption isotherm. Potentiostatic polarization results revealed that Tribulus terrestris .L extract act as mixed type inhibitor. The values of activation energy (Ea), free energy of adsorption (DGads), heat of adsorption (Qads), enthalpy of adsorption (DH) and entropy of adsorption (DS) were calculated. Surface analysis (FT-IR and SEM) was also carried out to establish the mechanism of corrosion inhibitor on mild steel corrosion in phosphoric acid medium.

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Mechanical alloying through high energy ball milling was used to produce Ni-Fe alloy powders starting from elemental Ni and Fe powders of average particle size 80 and 25μm respectively. High Energy Planetary ball milling at room temperature wasperformed for various time durations ranging between 2 to 100 h. Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD) and Particle Size Analyzer were used for characterization. In 40%Ni-Fe the grain size first decreases with milling till 8 h and then increases reaching the next highest value at 16 h. After 16h the grain size continuously decreases reaching the lowest value of 7.3 nm at the end of 100h of milling. In 75%Ni-Fe alloy the grain size decreases continuously with milling h reaching the value of 34 nm at 100 h of milling. It is observed from 40%Ni-Fe that the particle size decreases continuously with milling time as the fracturing forces dominate over the cold welding entire period. At the end of milling the particle size does not change appreciably due to the equilibrium between the fracturing and cold welding forces. The particle size reaches the lowest value of 0.967 μm at the end of 100 h of milling. In 75%Ni-Fe alloy during 2 to 8 h of milling the particle size remain constant at 13.5 μm. During 32 to 64 h of milling, it is observed that the particle size remains constant at 7.5 μm. This may be due to equilibrium between the fracturing and cold welding forces in these regions of milling. The particle size decreases after 64 h and reaches the lowest value of 3 μm at 100 h of milling.

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The lyoluminescence (LL) emission spectra of luminol, fluroscein & rhodamine-B (R-B) dyes have been recorded at optimum concentration of the activators in aqueous ethylamine. An enhancement of three & seven fold incrases in LL intensity of luminal has been observed at 9 ?10-5 M concentration of fluoresce in & 8?5-5 M concentration of R-B respectively, in the binary solution of luminol & dyes. The LL emission spectra of luminol-dye mixture are recorded at the concentration of enhancement in LL intensity of luminol. These spectra in resolution, should foure mission bands. The first two bands of 430 & 470 nm corresponds to LL to luminol & the other two bands of longer wavelength emission corresponds to LL of dye molecule. The observed enhancement of LL intensity is explain with the help of a mechanism based on the reactions of colour centers with activities.

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The oxidation of isoprene (2-methyl-1,3-butadiene) is known to play a central role in the photochemistry of the troposphere, but is generally not considered to lead to the formation of secondary organic aerosol (SOA), due to the relatively high volatility of known reaction products. However, in the chamber studies described here, we measure SOA production from isoprene photo-oxidation under high-NOx conditions, at significantly lower isoprene concentrations than had been observed previously. Mass yields are low (0.9-3.0%), but because of large emissions, isoprene photo-oxidation may still contribute substantially to global SOA production. Results from photo-oxidation experiments of compounds structurally similar to isoprene (1,3-butadiene and 2- and 3-methyl-1-butene) suggest that SOA formation from isoprene oxidation proceeds from the further reaction of first-generation oxidation products (i.e., the oxidative attack of both double bonds). The gas-phase chemistry of such oxidation products is in general poorly characterized and warrants further study.

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Theoretical investigation has been carried out to evaluate the effect of weakly ionized plasma medium on radiation characteristics of rectangular microstrip antenna. Elemental area has been utilized to obtain the components of radiated fields which further extrapolated to obtain the components of radiation for rectangular patch. Further these expressions are modified for weakly ionized plasma medium. It has been observed that the presence of plasma medium affect the radiation characteristics of microstrip antennas to a great extent. The investigation reveals that in weakly ionized plasma, the level of first side lobe increases with increasing value of wp/w. The effective permittivity is also found to decrease with higher values of wp/w, as a result of which microstrip patches becomes more omnidirectional.

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Present study describes the first total synthesis of a cyclic heptapeptide, stylisin 1 (8) via coupling of tetrapeptide Boc-L-Tyrosinyl-L-Prolyl-L-Leucyl-L-Proline-OH and tripeptide L-Phenylalanyl-L-Isoleucyl-L-Proline-OMe followed by cyclization of linear heptapeptide segment. Structure elucidation of synthesized cyclopeptide was done on basis of detailed spectral as well as elemental analysis. From the results of pharmacological screening, it was concluded that cyclopeptide 8 possessed moderate cytotoxicity against Dalton's lymphoma ascites (DLA) and Ehrlich's ascites carcinoma (EAC) cell lines with IC50 (inhibitory concentration, 50%) values of 10.6 and 14.6 μM. Furthermore, cyclopeptide 8 exhibited moderate to good antimicrobial activity against Gram -ve bacteria Klebsiella pneumoniae and Pseudomonas aeruginosa, dermatophytes and Candida albicans with minimum inhibitory concentration (MIC) of 6 μg/ml.

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In the present study the effect of pre-irradiation deformation on the thermoluminescence (TL) of g-irradiated undoped and Cu++ doped NaCl crystals for different impurity concentrations, radiation doses etc. have been studied. Two peaks at 392? K and 465?K respectively are observed in TL glow curves of pre-irradiation deformed undoped and Cu++ doped NaCl crystals. The intensities of both the peaks in TL glow curves increases linearly with increasing pre-irradiation deformation of the pure and Cu++ doped NaCl crystals. It is found that increase in the TL peak-II with strain is higher as compared to that of TL peak-I. The temperature Tm1 and Tm2 corresponding to the first and second peaks in TL glow curves respectively, do not change significantly with the pre-irradiation deformation of the crystals.

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In the present work, synthesis of Polyaniline (PANI) is carried out by chemical oxidation method by using ammonium persulphate as an oxidant. PANI- SrTiO3 composites were synthesized by using various weight percentages (10, 20, 30, 40 and 50wt %) of SrTiO3 in PANI by insitu polymerization. The composites are characterized by using various techniques such as XRD and SEM. XRD micrographs indicate that SrTiO3 is homogeneously distributed in the PANI. SEM micrograph indicates that PANI / SrTiO3 have many aggregated pores. The Dielectric constant and Dielectric tangent loss are studied by sandwiching the pellets of these composites between the silver electrodes. It is observed that dielectric constant decreases with increasing frequency where as at higher frequencies dielectric constant remains constant. PANI and its composites exhibit small value of dielectric loss at higher frequency. The AC conductivity is studied in the frequency range from 102Hz-106Hz. From these studies it is found that, AC conductivity remains constant at lower frequency and increase rapidly at higher frequency, which is characteristics behaviour of disordered materials. Hence, this composite finds applications such as sensor devisees.

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A method suggested by Ganguly is considered for the determination of kibnetic parameters of a differential thermal analysis (DTA) curve. The method is applied both to numerically computed and experimental DTA peaks and encouraging results have been obtained.

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Every conductor belongs to transportentropy function such that when an electric change passes, there is entropy absorbed or evolved between any two points of the conductor. If follows that the peltier heat per unit change developed at the isothermal junction of the two conductors is given by p = T.S where p = Peltier heat, T = Temperature and S= entropy function. Secondly for a single conductor under temperature gradient dT/dx, the Thomson heat is given by s=T.ds/dt, S appears as being the thermoelectric power. The present communication is an attempt to discuss quantitatively the thermodynamic relations of the thermoelectricity. The thermoelectric power of a conductor appears as a transport of the electric charge or, more lossely, of conduction electrons. William Thomsom13 himself suggested that the Thomson heat might be regarded essentially as a specific heat of electricity in differentmetals, since they appear the quantity of heat absorbed or evolved by the unit current electricity in passing from cold to hot or hot to cold, between localities differing by one degree of temperature in each metal, respectively.

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CuIn2Se4 thin films are developed by electrochemically deposition technique on stainless steel substrates in galvanostatics mode from an aqueous acidic bath. Which contain CuSO4, InCl3 and SeO2.the properties of film are studies by deposition parameters such as deposition time, current density, deposing potential, pH of bath, temperature of bath, are optimized and crystal structure are studied by X-Ray diffraction analysis. Optical properties studied with effect of temperature. Surface morphology observed by Scanning Electron Microscopy with annealing at different temperature.

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Corrosion rate (Progressive) of mild-steel (MS), zinc and aluminum have been determined under outdoor conditions of exposure at Vapi (South Gujarat) representing an industrial environment. Mild steel (MS), zinc and aluminium plates exposed during November 2005 indicates corrosion rate of 791, 131 and 2.4 mg/sq.dm for one month exposure period and 12731, 952 and 29.8 mg/sq.dm for mild steel, zinc and aluminium respectively for twelve months exposure period. Mild steel panels exposed vertically suffer less corrosion than those exposed at an angle of 45?. The resistivity towards the environment was in the increasing order of mild steel < zinc < aluminium. Corrosion rate of these three metals was found more in rainy seasons than the rate of winter and summer season.

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Four commercial non-ionic surfactant compounds, namely Bixin, Zenthoxylum almauta, Echitamin, Nyctanthin were tested as inhibition for corrosion of Copper 0.5 M sulphuric acid solution. Weight loss measurements, potentiostatic polarizatiors and cyclic voltammetry techniques were used in this study. It was found that all the four used compounds act as good inhibitors for acid corrosion of Copper. The inhibition efficiencies obtained by the three techniques were almost the same, and increases with increasing the surfactant concentration. The polarization studies show that all used compounds act also mixed inhibitors. The inhibition action of these surfactants is interpreted in view of their adsorption on the metal surface making a barrier to mass and charge transfer. It was found that the adsorption of compounds follows Longmuir isotherm. The values of free energy of adsorption for them were calcopperlated. It was found that the adsorption process is spontaneous and increases, for different surfactants, in the same direction as inhibition efficiency. The cyclic voltammetry shows that there is only one anodic peak corresponding to the dissolution reaction of electrode. The copperrrent of this dissolution peak was used also for corrosion rate measurements and in evaluation of inhibition efficiencies of the used compounds.

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AgInse2 thin film is developed by electrochemically deposition technique on stainless steel substrates in galvanostatics mode from an aqueous acidic bath containing AgCl3, InCl3, and SeO2. The growth kinetics of the film was studies by measurement of thickness i.e. Mass difference method. And the deposition parameters such as electrolyte bath concentration, deposition time, current density, and pH of electrolyte bath are optimized. The X-ray diffraction (XRD) analysis of the deposited film showed presence of polycrystalline nature. And the interplanner distance (d). The surface morphology studies by Scanning electron microscope (SEM) show that the deposited film is well adherent and uniform.

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The Te containg CdSe thin film were prepapred by electrochemical codepotion under potentiostatic control to study their current voltage behaviour, capacitance, charge density. Current - voltage measurement have also been carried out for the construction of Tafel plots to determine the exchange current density and corrosion rates. Electro synthesis of Te containing CdSe films have been electrosynthesized at - 0.600v Vs SCE (Saturated Calomal Electrode) on titanium subtract from Aqueous solution. The corrosion characteristics of the film have been studied by polarization techniques. This is study to investigate the effect of tellurium concentration on the composition, capacitance and corrosion parameters of CdSe films electro synthesis by electrochemical co-deposition. This is the study to investigate the effect of tellurium concentration on the composition, Capacitance, morphology and corrosion parameters of the CdSe Te thin films electrosynthesis by eletrodeposition.

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A simple, specific and precise high performance liquid chromatographic method has been developed for estimation of Glipizide in its pure and pharmaceutical dosage forms. A HPLC system consisting of a gradient pump, reverse phase C-18 analytical column, a variable UV-Visible detector set at 225 nm and an integrator was used. The mobile phase consisted of methanol and 0.115%w/v ammonium dihydrogen phosphate buffer and pumped at 1ml/min at ambient temperature. This RP-HPLC method was validated for its linearity, precision and accuracy. The calibration curve was linear in the range of 10 to 70 μg/ml).

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The stability constants of Cu (II), La (III) metal ions with substituted azoles has been studied by pH-metric technique at 0.1 M (KNO3) ionic strength at 27 ± 0.10C in aqueous medium. Also the effect of ionic strength on stability constants of chelates of azoles in 70% DMF-Water system with pH-metric technique has been studied. The data obtained was used to study the correct mechanism of complexation, to determine thermodynamic properties and to study proton-ligand and metal-ligand stability constants.

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High turbidity in water is a good indicative of undrinkable water quality and suggests contamination of water having suspended particles of heavy metals in it.Water treatment plants also fails to treat contaminated water associated with turbidity in it. The main objective of this study is to treat high turbidity water by Magnetite particles in the effect of a magnetic field,which enhances the rate of removal of turbidity from water.After magnetization magnetite particles can remove turbidity from 9600 NTU to 20 NTU. The use of magnetite particles are also pH friendly because they are more effective up to pH OF 6.0 to9.0. It has also been investigated that recycle of magnetite particles and their reuse is also recommendable. Cetyltrimethyl ammoniumbromide (CTAB) and other similar tri derivatives are found useful in regeneration of magnetite particles.

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A process for the preparation of nickel titanate, which comprises adding an aqueous solution containing ions of titanium and nickel, to an aqueous alkaline solution containing hydrogen peroxide. The resulting precipitate is recovered and heated at a temperature of 850 oC to give nickel titanate. The samples were then analyzed using a series of techniques including X- ray diffraction (XRD), Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and Thermo gravimetry (TG). The results indicated that nickel titanate nanopowders with particle size less than 100 nm could be obtained after calcination of precipitate at 850 oC.

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The general result of the Compton process is derived in this paper without the assumption that one of the particles should be initially at rest. Nor is it assumed that one of the particles is a photon.

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The main characteristics of the depletion layer, are obtained on the basis of a suggested model, according to which, the charge is distributed, not as a space charge but as surface charge on the lateral sides of the depletion layer. Comparative discussions of the results obtained according to both models are given. The dependences on the ratio ?? ?? and the applied voltage ?? ?? are clarified. Both forward and backward biases are also considered. Graphical representations for the obtained relations, considering an illustrative example on a silicon cell are also given.

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