Table of Contents - Volume 4 Number 1

A method for approximating multivariable linear discrete time-varying system is described. The method is based on minimizing the difference between the system outputs and the reduced order model outputs. The optimal model parameters are given by a set of non-linear equations. It is shown that when the output and the state of the model are equal, the synthesis simplifies to a linear problem. The results are illustrated by a numerical example.

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The satellite thermal control maintains temperatures of all satellite components within their allowable operational temperature limits, throughout the satellite mission. Aluminum and composite materials are used for satellite structures. Thermal control performance, structural properties and manufacturing cost are important factors in selection of satellite structures. In this paper, we present the comparison of thermal performance of aluminum and composites, used as structural materials for a small satellite. We have also studied the effect of thermal contact resistance, between the satellite main components and the structural elements, on the overall thermal performance of these satellite structures. The temperature results, for major satellite components in the two types of structures considered in this paper, show the improvement in the overall thermal performance of composite satellite structures over the aluminum satellite structure.

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In this paper, we investigate the problem of existence of positive solutions for the nonlinear fourth order boundary value problem: D4u(t) = la(t)f(u(t)), 0 < t < 1, u(0) = u"(0) = u'(1) = u"'(1) = 0, where l is a positive parameter. By using Krasnoesel?skii?s fixed point theorem of cone, we establish various results on the existence of positive solutions of the boundary value problem. Under various assumptions on a(t) and f(u(t)), we give the intervals of the parameter l which yield the existence of

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The concept of deriving the structures of isomers of boranes using Kiremire?s and Lipscomb?s equations has been extended to the derivation of the structures of carboranes. The carbon atom is considered to be isoelectronic to the boron atom plus one electron. Just like the boranes, the carboranes also obey the relationship K = s +2t +y. A good number of carborane clusters both neutral and ionic are given as illustrative examples.

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A highly sensitive and accurate method for preconcentration and determination of ultra trace amounts of cobalt and nickel ions in water samples is proposed. The preconcentration is achieved using C18-silica extraction disks modified with thioridazine?HCl (THR) . The retained ions on the prepared solid phase was eluted with 10 ml of 0.01 M nitric acid and measured by inductively coupled plasma-optical emission spectrometry (ICP-OES). The influence of the type and amount of eluent used, pH, sample and eluent flow rates, amount of THR and the effect of other ions on extraction efficiency were investigated. The limits of detection of the method were 0.12 and 0.09 μg l-1 for cobalt and nickel, respectively, and provide an enrichment factor of 100. The results obtained on 10 successive extractions and elution cycles revealed relative standard deviations of 1.8 and 1.9% for cobalt and nickel, respectively. The proposed method has been applied to the determination of ultra trace amounts of cobalt and nickel ions in natural and synthetic water samples with satisfactory results.

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A method of solvent extraction is described for concentrating and separating the copper from an aqueous alkaline solution (pH 9-10) of steel into an organic solvent prior to analysis by flame atomic absorption spectroscopy. In this research first, ammonium pyrrolidinedithiocarbamate (APDC) as a chelating agent, and tartaric acid as masking agent for ferric ion, were used then, solvent extraction, separation of copper from steel and subsequent determination of copper in the organic solvent were carried out. The copper content of four separate samples of each of the standard steels was extracted as a Cu/APDC complex into MIBK. The results obtained for steel samples were very near to the certificated values particularly when iron is added to the standard solutions. Thus, APDC could be used successfully in the extraction of copper from steel samples even when iron is not added to the standards.

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In this research, we were interest to study the electrochemical behaviour of modified composite electrode" [Co-Ph3]2+, 2ClO4-complex? mixed with ?graphite powder?, at different per cent weights and pressures in aqueous and THF media. According to our results in aqueous solution, 0.1M NaClO4, one irreversible system CoII/CoI (DEp @ 250 mv) and in ?THF + TBAP 0.1M, two irreversible systems CoII/ CoII and CoII/CoIand appear and the later is more irreversible. The main idea is to verify electro-catalytic assis

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Nano particles of nickel-cobalt oxide are prepared by chemical co-precipitation method by decomposition of their respective metal chlorides, sodium carbonate and EDTA. The average particle size is determined from X-ray line broadening and the diffractogram is compared with JCPDS data and the phase of the particle formed is determined and the shift in the D-value due to the nano nature is also analyzed. The nanoparticles formed have spinel structure. The effect of sintering temperature on the particle size is analyzed. The size of the particles is confirmed by TEM. The surface morphology is revealed by SEM image. EDS confirms the elements present in the sample. The low temperature dc conductivity studies of the sample were carried out and it was seen that the activation energy for the temperature range 100K-250K is 0.37ev and for the range 250K-350K is 0.62ev.The conductivity in the temperature range 275K-350K is much larger than the conductivity in the range 100K-250K. This value is much greater than the value reported for bulk nickel cobalt oxide (0.03 eV). It indicates the enhancement of conductivity in nanosized form of this material.

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The trace concentrations of copper in several British steel samples and standards have been investigated in this research by direct method using hydrochloric and nitric acid mixture, and sulphuric acid, Phosphoric acid and water mixture. Three standard steels containing copper in the range of 0.13% - 0.39% were used. These were low alloy steel B.C.S. No. 257/1 (0.13% Cu), carbon steel B.C.S. No. 239/2 (0.18% Cu) and alloy steel B.C.S. No. 253/1 (0.39% Cu). The dissolution procedure of steels, led to a solution which was analysed directly by atomic absorption spectrophotometry. Absorption due to copper was measured at 324.8 nm by atomizing the solution in a 10 cm slot burner using an air-acetylene flame with air flow rate 5.2 L/min and acetylene flow rate 1.2 L/min and operating the hollow cathode lamp at 5 mA. Burner height was set at point 6. The appropriate calibration solutions were aspirated, followed by the sample solutions. Water was aspirated between each test when the zero was checked. The copper content of the sample solutions were read from the calibration graphs. The absorption of each solution measured at least three times. The results obtained in this research for copper content of steel samples indicate that a mixture of hydrochloric and nitric acids is to be preferred as the solvent medium, especially when iron is added to the standard solutions, when the copper contents found are near to the certificate values.

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A sensitive, selective and rapid method has been developed for the determination μg l-1 level of cobalt based on the rapid reaction of cobalt(II) with N-benzoyl-N-phenylhydroxylamine (BPHA) and the solid phase extraction (SPE) of the colored chelate with Waters Porapak Sep-Park C18 disk. The BPHA can react with Co(II) in the presence of pH 3.9 acetic acid -sodium acetate buffer solution and cetyl trimethylammonium bromide (CTMAB) medium to form a violet chelate of a molar ratio 1:2 (cobalt to BPHA). This chelate can retained on Waters Porapak Sep-Park C18 disk quantitatively when they passed the disk as aqueous solution. After the enrichment finished, the retained chelate can be eluted from disk by 2.5 ml of ethanol (contain 5% acetic acid). In the measured solution, the molar absorptivity of the chelate is 1.58?105 l mol-1 cm-1at 636 nm, and Beer?s law is obeyed in the range of 0.01-0.42 μg ml-1. The relative standard deviation for 11 replicate sample of 0.01 μg ml-1 level is 2.28%. The detection limit is 0.01 μg l-1 (in original samples). This method can be applied to the determination of mg l-1 level of cobalt in drinking water with satisfactory results.

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In this research, we were interest to study the electrochemical behaviour of modified composite electrode" [Co-Ph3]2+, 2ClO4-complex? mixed with ?graphite powder?, at different per cent weights and pressures in aqueous and THF media. According to our results in aqueous solution, 0.1M NaClO4, one irreversible system CoII/CoI (DEp @ 250 mv) and in ?THF + TBAP 0.1M, two irreversible systems CoII/ CoII and CoII/CoIand appear and the later is more irreversible. The main idea is to verify electro-catalytic assis

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Polymer nanocomposites (PNCs), defined as polymers bonded with nanoparticles to produce materials with enhanced properties, have been in existence for years but are recently gaining momentum in mainstream biosensor, drug delivery, gas barrier, commercial packaging, automobile, fuel and flame retardant materials industries. This article is designed to handover an extensive report on polymer nanocomposite research. It starts with a brief introduction of nanotechnology and nanocomposite to create a base for the better understanding of core of the subject. It discusses and correlates the scientific principles and mechanisms with various techniques for the synthesis of different PNCs. In this article, efforts are made to give necessary foundation and tools to address system-specific complexity and explain the properties of PNCs with the help of scientific framework which gives clues for the processing of PNC of desired and altered properties. Characterization techniques of these materials are briefly depicted and finally a summary of the vast commercial applications along with its health and safety concerns is . Thus this article offers the general discussion on polymer nanocomposites processing and synthesis, characterization and applications.

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A method of solvent extraction is described for concentrating and separating the copper from an aqueous solution of steel into an organic solvent prior to analysis by flame atomic absorption spectroscopy. The choice of possible chelating agents and solvent was made after a series of preliminary experiments. More detailed experiments were then carried out with those solvent extraction systems which appeared to be most promising. This research was carried out by using NaDDC and ZnDBC as chelating agents for carrying out solvent extraction, separation of copper from steel and subsequent determination of the copper directly in the organic solvent. The copper content of steel sample solutions were determined by extraction as either a copper diethyldithiocarbamate (CuDDC) complex from aqueous alkaline solution into methyl isobutyl ketone (MIBK) or copper dibenzyldithiocarbamate (CuDBC) complex from the acidic solution into MIBK, and then by spraying the MIBK extract into an air-acetylene flame. The conclusion is that for a rapid determination of copper in the steel samples, direct atomization of aqueous solution when dissolved in hydrochloric acid and nitric acid mixture is to be preferred if high accuracy is not required (~ 4% error). More accurate results can be obtained using a longer extraction procedure using ZnDBC (~ 1% error).

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The different catalysts like Mont. K-10 clay, Mont. KSF clay, Yb (OTf)3, Sc(OTf)3, Dy (OTf)3, Gd (OTf)3, and InCl3 can be recycled many times without loss of catalytic activity during the synthesis of tetrahydroporphyrin under microwave irradiation.

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The charge transfer complexes were prepared and characterized by I.R. and elemental analysis. The molecular formula were found to be Co (ETH)2- I2, Ni (ETH)2- I2, Cu (ETH)2- I2, Zn (ETH)2- I2, Co (ETH)2- AgClO4, Ni (ETH)2- AgClO4, and Zn (ETH)2 - AgClO4,.

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The inhibition effect of Cytisine derivative namely [ N-( 3- Methylthio-5-acetamido-1,2,4-thiadiazolyl ) cytisine ] on mild steel in 1M H2SO4 has been studied by using weight loss, electrochemical polarization and scanning electron microscopic (SEM) techniques. It has been concluded that percentage inhibition increases with increase in concentration of inhibitor. The adsorption of [ N-( 3- Methylthio-5-acetamido-1,2,4-thiadiazolyl ) cytisine ] on mild steel surface in 1M H2SO4 obeys Langumir adsorption isotherm, surface analysis studies are carried out to establish the mechanism of corrosion inhibition. The polarization data indicate that this compound act as very good cathodic inhibitors for mild steel in 1M H2SO4 and its inhibition efficiency increases with concentration and the highest value obtained is around 92%.

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Single crystals of potassium acid phthalate (KAP), Nickel Doped KAP (NiKAP) and Cobalt doped KAP(Co KAP) have been grown from aqueous solutions by solvent evaporation method. The effect of these metal irons on surface morphology, structure, optical and mechanical properties have been studied. Single crystal XRD studies of these crystals confirm that both the added impurities have modified the structure of the KAP crystals in a similar manner. The presence of dopants in the crystal lattice have been further confirmed by FTIR analysis. The stoichiometric composition of both the doped crystals have been studied using EDAX analysis. Optical absorbance was carried out for all the crystals. The absorbance in the visible region observed in both the doped crystals was assigned to their d-d transitions. Micro hardness of the pure and doped crystals were found using Vickers?s Hardness Technique.

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Principle eigen value of distance matrix for salicylhydroxamic acids derivatives have determined and then correlated with Physicochemical properties namely logP, Molar volume and Parachor values. Excellent results have been obtained while multiple linear graph methods have been used to calculate biological & physico-chemical properties of different derivatives.

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The maximum bubble pressure method was used to measure the dynamic surface tension of triton x-100 solutions (below CMC, at the CMC, above CMC). SensaDyne surface tensiometer was used which employs maximum bubble pressure method. Wilhelmy plate method was employed to measure static surface tension. Measurements were performed at 28?C. Equilibrium surface concentration was estimated from Gibb?s adsorption equation. The Ward and Tordai equation was used to get the diffusion coefficient. The results are in agreement with the data obtained by other methods. The demicellization rate constant is obtained from the Ward and Tordai equations. It is found that the rate constant strongly depends on surfactant concentration.

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The charge transfer complexes were prepared and characterized by I.R. and elemental analysis. The molecular formula were found to be Co (ETH)2- I2, Ni (ETH)2- I2, Cu (ETH)2- I2, Zn (ETH)2- I2, Co (ETH)2- AgClO4, Ni (ETH)2- AgClO4, and Zn (ETH)2 - AgClO4,.

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The effect of change in power level of microwave ir-irdation on product yield in organic reaction using heterogeneous Mont. K-10 catalyst in explored.

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The inhibitive effect of (agar) on the corrosion of mild steel in 1M HCl has been investigated using gravimetric and electrochemical techniques. The percentage inhibition efficiency was found to increase with increasing the concentration of inhibitor and with decreasing temperature. From both gravimetric and electrochemical experiments, the inhibition efficiency of the agar was found to be in the 92 -98 % range for 1M HCl medium. Galvanostatic study indicates that this compound act as a mixed type corrosion inhibitor. The rate of corrosion of mild steel rapidly increases with temperature over the temperature range of 30?C to 60?C, both in absence and presence of inhibitor. Thermodynamic parameters for adsorption process have been calculated using the Langmuir?s adsorption isotherm.

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The inhibitive effect of (agar) on the corrosion of mild steel in 1M HCl has been investigated using gravimetric and electrochemical techniques. The percentage inhibition efficiency was found to increase with increasing the concentration of inhibitor and with decreasing temperature. From both gravimetric and electrochemical experiments, the inhibition efficiency of the agar was found to be in the 92 -98 % range for 1M HCl medium. Galvanostatic study indicates that this compound act as a mixed type corrosion inhibitor. The rate of corrosion of mild steel rapidly increases with temperature over the temperature range of 30?C to 60?C, both in absence and presence of inhibitor. Thermodynamic parameters for adsorption process have been calculated using the Langmuir?s adsorption isotherm.

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We have predicted the phase transition pressure and corresponding relative volume change of LuSb having NaCl type structure under high pressure using three body interaction potential approaches (TBIPA). The potential model is consisting of long range columbic, three body interaction forces, short range overlap repulsive forces operative up to next neighbor ions and short-range van der Walls interaction with zero point energy effects. We have obtained phase transition and relative volume change, which are in close agreement with experimental approach. Thus TBIPA is promising with respect to the prediction of transition pressure and stability of rare earth compounds.

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A rapid and facile synthesis of tetraphenylporphyrin using K-10 clay as catalyst under microwave irradiation is carried out efficiently.

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A method involving the use of solution electrophoresis is described for the study of equilibria in metal-ligand binary complex systems in solution. The technique is based on the migration of metal ion in solution under an electric field with the complexants added to the background electrolyte at different pH in an electrophoretic tube.

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Warfarin acetals are synthesized by intra cyclodehydration reaction in presence of Mont. KSF clay in good yields under microwave irradiation.

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Gliquidone (Glurenorm) is chemically I-Cyclohexyl-3-4- (2-(3,4-dilhydro-7-methoxy-4, 4-dimethyl-1, 3-dixo-2 (I-H)- Isoquinoly) ethyl benzene sulphenyl urea, an oral antidiabetic agent, forms 2:1 complex with zinc acetate in alcoholic medium. The present study describes the synthesis, analysis and composition of gliquidane Zn complex.

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An innovative solution electrophoresis technique has been used for this study of methyl cysteine complexes of some metals ions viz. Th (IV), Fe (III), Cr (III) and Al (III). 1 : 1 complex is formed by Th (IV) while 1:1 and 1:2 complex is form by Fe (III), Cr (III) and Al (III). The stability constant of the complexes formed were found to be : log k1 = 8.25 (for Th (IV)), log k1 = 7.84, log k2 = 6.83 (for Fe (III)), log k1 = 7.64, log k2 = 4.72 (for Cr (III)), log k1 = 7.33, log k2 = 5.15 (for Al (III)) at 35?C and ionic strength 0.1 M.

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An attempt has been made for the experimental evaluation to study the effect of the hexagonal finned surface on the local heat transfer coefficients between the impinging circular air jet and flat plate. Reynolds number is varied between 7000 and 30000 based on the nozzle exit condition and jet to plate spacing between 0.5 to 6 times of the nozzle diameter. The fins used are in the form of hexagonal prism of side 2.04 mm and height of 2 mm spaced at a pitch of 7.5 mm.on the target plate. It is observed that there is increase in the heat transfer coefficient up to 68 % depending on the nozzle plate spacing and the Reynolds number.

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It is a well-established fact that the Web applications require frequent maintenance because of cutting–edge business competitions. Further, such applications are maintained by third party in majority of the cases. This paper emphasizes that the factors like Analyzability, Changeability, Scalability, Stability and Testability as defined by ISO9126 standards are not sufficient. It is important to consider factors like the capability of maintenance team, management attitude of both client and maintenance organization. Further, the capability of the original Web application developer is also important.

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The dielectric properties of molecular complexes have been formed by Co (ETH)2, Ni (ETH)2,
Cu (ETH)2, and Zn (ETH)2 (ETH represents, N-Ethoxycarbonylpyrrole-2-thiocarboxamide) and iodine have been studied in carbon tetrachloride. These studies provide a substantial information on the
geometry of these molecular complexes.

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Gallium nitride (GaN) is a next-generation semiconductor material with excellent potential for a range of technological application ,extending beyond the possibilities of established materials such as Si and GaAs. GaN is a wide band gap emiconductor making it well suited to blue/ violet light-emitting diodes, lasers and optical detectors, valuable for a range of application including wide bandwidth optical communications, high-density data storage, and energy-efficient generation of natural white light. Its wide band gap and high chemical stability also offer the prospect of high temperature electronic devices, of particular interest for down-hole instrumentation in the oil and gas industry and elsewhere. High saturated drift velocity and high thermal conductivity are valuable for high power switches for traction motor control,and devices for microwave generation .Tremendous amount of research activity is taking place world wide in fabricating and characterizing devices made from III-Nitrides and their alloys.We have carried out the current-voltage measurements and obtained clear rectifing junction for the case of GaN-Au ,while the system of Al-GaN-Al showed omic characteristics .Doping concentration and barrier height have been determined from the capacitance-voltage measurements.

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The K value has a strong correlation to molecular geometries of boranes, carboranes, metalloboranes and a large number of transition metal organometallic cluster systems. Its basis is the eight ( octet ) and eighteen electron rules. This paper provides simple examples which illustrate the link between the three dimensional geometry of a cluster and its K value. It also found that for the simple systems the K value is related to Wade?s skeletal electron pairs ( SEP ) by the equation K = 3( N-2).

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The conductance of the solution of beryllium soaps has been measured at 30?C + 0.05?C in pure benzene with a view to determined the critical miceller concentration (CMC), molar conductance at infinite dilution. The results show that the specific conductance of the solutions of a soap increases whereas the molar conductance decreases with the increase in the soap concentration but increases with increasing chain length of the soap. The value of CMC decreases with the increase in the chain length of soap. The viscosity measurements confirm that the soap molecules does not aggregate appreciably below the CMC and the results has been interpreted in terms of Einstein, Vand, Moulik, and Jones-Dole equations. The values of molar volume are in agreement.

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