Study of solvents for butadiene extraction by gas chromatography

Six solvents have been studied by GLC for separation of 1,3-butadiene from C₄-olefins having close boiling points. Infinite dilution activity coefficients and partition coefficients of five olefins have been determined in these solvents by conventional GLC-technique at 30 °C. Relative volatilities of olefins in solvents have been calculated and on this basis the solvents have been compared.     

Sahand Plasma Focus Emitted More Than 35 J in Yield Neon Soft X-ray

X-ray emission from neon plasma produced in Sahand Filippov type plasma focus device is investigated. Detecting system used in our experiments is a five channel pin diode detector. Soft X-ray emissions from neon gas at different charging voltages and working gas pressures are studied and optimum condition for production of soft X-ray for Sahand plasma focus facility is obtained. Results show that for every working pressure there is a charging voltage at which the average soft X-ray yield is maximum and this optimum charging voltage increases with increasing gas pressure. For 0.25, 0.50 and 0.75 Torr neon the optimum voltages are 12, 13 and 16 kV respectively. The highest average soft X-ray yields produced at 0.50 Torr which is about 35.87 ± 1.18 J. Also soft X-ray production decreased after a certain pressure which for our experiments is 0.50 Torr. The variation of relative hard X-ray yield with charging voltage and working gas pressure is also investigated. The results show that 0.50 Torr is also the best operating gas pressure for optimum hard X-ray production in Sahand Filippov type plasma focus device.     

Magnetic Reynolds Number and Neon Current Sheet Structure in the Axial Phase of a Plasma Focus

The Magnetic Reynolds Number (MRN) in neon is computed as a function of Neon shock speed. The magnetic field profiles at various positions in the axial run down phase of the INTI Plasma Focus device are measured over a range of pressures from 2 to 20 Torr. These profiles are assessed for good electromagnetic coupling including measuring the current per unit current sheet thickness as a comparative measure of current sheet diffusion. It was found that at an axial current sheet speed of over 3.5 cm/μs (corresponding to MRN > 15), the current sheet has a compact profile with current density of 55 kA/cm of sheet thickness whereas at speeds below 2.8 cm/μs (corresponding to MRN < 10) the profile is more diffuse with current density less than 30 kA/cm of sheet thickness. Based on these studies it is proposed to take a speed of 3 cm/μs corresponding to an MRN of 10 as the minimum speed of neon current sheet below which the electromagnetic coupling begins to weaken.     

Quasi-static analysis of three-line microstrip symmetrical coupleron anisotropic substrates

A method for analyzing three asymmetrically coupled microstrip lines on an anisotropic substrate has been developed. Computer programs based on the method of moments have been employed and the coupler mode impedance, coupling constant, and phase velocity, as functions of the anisotropy ratio, have been obtained     

Low-frequency noise measurement-based reliability testing of VLSI interconnects with different geometry

Low-frequency noise measurements were performed on thin metallic very large-scale integration (VLSI) interconnects of three different geometries. These measurements were carried out under stressing current densities between 1.0/spl times/10/sup 5/ A/cm/sup 2/ and 2.2/spl times/10/sup 6/ A/cm/sup 2/ at different ambient temperatures up to 280/spl deg/C, in order to investigate the dependence of low-frequency noise on the geometrical shape of the VLSI interconnects. The behavior of these samples under these conditions is analyzed in this letter.     

Anomalous electrical transport behavior in nanocrystalline nickel

We have prepared nanocrystalline Ni (n-Ni) samples of grain sizes 40-100?nm using a polyol method and investigated the electrical transport on their compacted pellets in the temperature range 3-300?K. The resistivity, ρ, decreases nearly linearly with increase in compaction pressure but without a change in its slope, dρ/dT. ρ is anomalously large, and is strongly temperature and grain-size dependent. The resistivity at room temperature, ρ(300?K), is in the range ～40-759?μΩ?cm but with a positive coefficient of resistivity α (metallic). This is associated with the significantly enhanced dρ/dT with increase in residual resistivity ρ(0). These characteristics are attributed to the disorder in the grain boundaries that represents effectively a series resistor network.     

A continuous-time least mean-phase adaptive filter for power system frequency estimation

The mean squared error criterion is widely used in the literature. However, there are applications where the squared error is not the primary parameter affecting the performance of a system. In this paper, we introduce a cost function that is based on the phase error. The criterion is useful for applications where the performance depends primarily on the phase of the estimated (recovered) signal. A continuous-time adaptive filter is then developed using the proposed criterion in stochastic differential equation formalism. The proposed adaptive filter is used to estimate power system frequency where the formulated structure is very simple. The three-phase voltages are converted to a complex form for processing by the proposed algorithm. The performance of the new algorithm is studied through simulations at different situations of the power system.     

SOLUBILISED WAXES AND THEIR INFLUENCE ON THE FLOW PROPERTIES OF LUBE OIL BASE STOCKS

ABSTRACT

The physico-chemical properties of Lubricating oil base stocks (LOBS) are generally influenced by the type/nature and concentration of solubilised waxes present in them. Detailed composition of the solubilised waxes, saturates and aromatics present in LOBS and its distillate fractions has been sludied. Further the influence of these solubilised waxes and as well of saturates/aromatics on the flow properties particularly pour point, viscosity and viscosity temperature relationship of LOBS sample and its distillate fractions have been investigated. The response of a commercial pour point depressant additive with varying composition of solubilised waxes in lube oil base stock sample has also been studied.     

Energy dependent cluster formation in heterogeneous wireless sensor network

The applications of Wireless Sensor Network is increasing rapidly in almost every domain. So, the limited node’s battery life in the network should be utilized efficiently. Various approaches have been proposed earlier to lessen the usage of energy in the network and to enhance the network lifespan. In this paper we are proposing an approach for efficient cluster head selection namely Energy Dependent Cluster Formation in Heterogeneous Wireless Sensor Network (EDCF) to enhance the lifespan of network. The simulation of the proposed EDCF technique is performed in MATLAB simulator and to measure its performance the comparison is performed with various existing protocols. The proposed EDCF protocol has shown the enhancement in the lifespan of the network as compared to the previous clustering approaches.

     

Why only blue in the traditional architecture of western Himalaya,India?

The local environment defines the traditional designs and color of buildings in remote wilderness areas. Color, an integral element of the traditional architecture, is related to the culture, experience, perception, and beliefs, which forms a part of the traditional knowledge of the user. Some ethnic groups have been using some specific color patterns in their houses for generations, which have been carried forward in their traditions and customs. Recognizing this, a study to document the color preference and motivations for the preference of specific colors by an ethnic community residing in the interior valleys of western Himalaya was conducted. By group discussions, 13 indicators, which further merged into five motivation categories, were identified. Semistructured interviews (n = 159) were conducted to assess the perception of selected ethnic groups toward color preference. This study reveals that color preference in architecture is influenced by psychological and sociocultural reasons that vary with gender and age classes.