Theoretical Investigation of Magnetohydrodynamic Radiative Non-Newtonian Fluid Flow over a Stretched Surface

The aim of this study is to investigate the heat and mass transfer in magnetohydrodynamic Newtonian and non-Newtonian fluid flow over a stretched domain in the presence of thermal radiation, chemical reaction, Soret and Dufour effects. In addition to this, we also considered the aligned magnetic field (i.e. the magnetic field applied at different angles) along the flow direction and dual solutions are executed for the transverse and aligned magnetic field cases. The governing system of equations is transformed as the system of ODEs with the help of suited similarity transforms. The resulting equations are solved numerically with the aid of the shooting process. The graphical and tabular results are explored to discuss the flow, thermal and concentration behavior along with the heat and mass transfer rate. Keywords: MHD, Aligned Magnetic field, Soret and Dufour effects, Radiation, Chemical reaction

Magneto Hydrodynamic Flow of Dissipative Non-Newtonian Fluid over an Exponential Stretching Surface with Thermal Radiation

Numerical investigation is carried out to analyze the flow, heat and mass transfer behavior of magnetohydrodynamic non-Newtonian fluid (Casson) over a stretched surface with thermal radiation, chemical reaction and viscous dissipation effects. The governing PDEs are transformed as ODEs with the help of suited similarity transform. The effective Matlab package bvp5c is used to obtain the numerical solutions of the transformed equations. The impact of pertinent parameters on the common profiles (flow, temperature and concentration) is discussed in detail with the assistance of graphical illustrations for Casson and Newtonian fluid cases. Tabular results are presented to explain the nature of the wall friction, local Nusselt and Sherwood numbers. Keywords: Magnetohydrodynamics; Radiation; Dissipation; Casson; Chemical reaction

Size--sensitive melting characteristics of gallium clusters: Comparison of Experiment and Theory for Ga17+_{17}{}^{+} and Ga20+_{20}{}^{+}

Experiments and simulations have been performed to examine the finite-temperature behavior of Ga$_{17}{}^{+}$ and Ga$_{20}{}^{+}$ clusters. Specific heats and average collision cross sections have been measured as a function of temperature, and the results compared to simulations performed using first principles Density--Functional Molecular--Dynamics. The experimental results show that while Ga$_{17}{}^{+}$ apparently undergoes a solid--liquid transition without a significant peak in the specific--heat, Ga$_{20}{}^{+}$ melts with a relatively sharp peak. Our analysis of the computational results indicate a strong correlation between the ground--state geometry and the finite--temperature behavior of the cluster. If the ground--state geometry is symmetric and "ordered" the cluster is found to have a distinct peak in the specific--heat. However, if the ground--state geometry is amorphous or "disordered" the cluster melts without a peak in the specific--heat.Comment: 6 figure

VLSI Implementation of Encoder and Decoder for Advanced Communication Systems

Forward Error Correction (FEC) schemes are an essential component of wireless communication systems.Present wireless standards such as Third generation (3G) systems, GSM, 802.11A, 802.16 utilize some configuration of convolutional coding. Convolutional encoding with Viterbi decoding is a powerful method for forward error correction. The Viterbi algorithm is the most extensively employed decoding algorithm for convolutional codes which comprises of minimum path and value calculation and retracing the path. The efficiency of error detection and correction increases with constraint length. In this paper the convolutional encoder and viterbi decoder are implemented on FPGA for constraint length of 9 and bit rate ½

Energy optimization of 6T SRAM cell using low-voltage and high-performance inverter structures

The performance of the cell deteriorates, when static random access memory (SRAM) cell is operated below 1V supply voltage with continuous scale down of the complementary metal oxide semiconductor (CMOS) technology. The conventional 6T, 8T-SRAM cells suffer writeability and read static noise margins (SNM) at low-voltages leads to degradation of cell stability. To improve the cell stability and reduce the dynamic power dissipation at low- voltages of the SRAM cell, we proposed four SRAM cells based on inverter structures with less energy consumption using voltage divider bias current sink/source inverter and NOR/NAND gate using a pseudo-nMOS inverter. The design and implementation of SRAM cell using proposed inverter structures are compared with standard 6T, 8T and ST-11T SRAM cells for different supply voltages at 22-nm CMOS technology exhibit better performance of the cell. The read/write static noise margin of the cell significantly increases due to voltage divider bias network built with larger cell-ratio during read path. The load capacitance of the cell is reduced with minimized switching transitions of the devices during high-to-low and low- to-high of the pull-up and pull-down networks from VDD to ground leads to on an average 54% of dynamic power consumption. When compared with the existing ones, the read/write power of the proposed cells is reduced to 30%. The static power gets reduced by 24% due to stacking of transistors takes place in the proposed SRAM cells as compare to existing ones. The layout of the proposed cells is drawn at a 45-nm technology, and occupies an area of 1.5 times greater and 1.8 times greater as compared with 6T-SRAM cell

Platinum(II) and palladium(II) metallomacrocycles derived from cationic 4,4 '-bipyridinium, 3-aminopyrazinium and 2-aminopyrimidinium ligands

A series of cationic, ditopic N-donor ligands based on 4,4-bipyridine (4,4-bipy), 3-aminopyrazine (apyz) and 2-aminopyrimidine (apym), each incorporating two positively-charged N-heterocycles linked by a conformationally-flexible spacer unit, have been synthesised and treated with palladium(II) or platinum(II) precursors [M(2,2-bipy)(NO3)2] (M = Pd(II) or Pt(II)) to form highly cationic metallocyclic species. Treatment of 1,6-bis(4,4-bipyridinium)hexane nitrate with [M(2,2-bipy)(NO3)2] in aqueous solution, followed by the addition of KPF6, resulted in the formation of the [2+2] species [M2(2,2-bipy)2{4,4-bipy(CH2)64,4-bipy}2](PF6)8. Treatment of [Pd(PhCN)2Cl2] with 1,3-bis(4,4-bipyridinium)propane hexafluorophosphate in MeCN afforded [Pd2Cl4{4,4-bipy(CH2)34,4-bipy}2](PF6)4. When the cationic apyz or apym ligands were used in aqueous solution, the analogous metallomacrocycles did not form. Instead, deprotonation of the exocyclic amino group occurred upon coordination of the ligand to afford a tetranuclear [4+2] species in the case of platinum(II), with Pt(II)Pt(II) bonding supported by strong UV-vis absorption at = 428 nm which was assigned to a metal-metal-to-ligand charge transfer (MMLCT) band. Thus, treatment of 1,6-bis(3-aminopyrazinium)hexane nitrate with [Pt(2,2-bipy)(NO3)2], followed by the addition of KPF6, led to the formation of the red species [Pt4(2,2-bipy)4{apyz(CH2)6apyz–2H}2](PF6)8. No related products could be identified with palladium(II), consistent with the low propensity for this metal ion to form strong Pd(II)Pd(II) bonding interaction

Structural Analysis and Optimization of Nozzle Attachment on Channel Shell Design

In Channel shells, Nozzles are required for inlet and outlet purposes either to carry fluids or for providing multipurpose connections. If these nozzles present on peak of the dish end do not disturb the symmetry of the shell. However sometimes process requires that nozzles to be placed on the periphery of the shell. These nozzles disturb the symmetry of the shell. Geometrical parameters of nozzle connections may significantly vary even in one channel shell. These nozzles cause geometric discontinuity of the shell wall. So a stress concentration is created at the junction. Hence a detailed analysis is required. If nozzles are placed on the periphery of a channel shell, they disturb the axis symmetry of the system and cause eccentricity. Sometimes this cause generation of a couple & lead to a structural imbalance. So that it need to analysed in FEA to understand effects of nozzle on Stress attributes of the shell. This work also studies the effect of eccentricity of the nozzles under varying thickness of shell and reinforcement pad. The effect of material concession for nozzle and Shell on the stress induced is also studied. From the results obtained by ANSYS, optimum study was performed by response surface methodology to obtain optimum shell thickness and reinforcement pad thickness for different class of materials

Relation between reversal dominance time and carrying capacities in multiplex ecological ammensalism - A numerical study

The paper aims to investigate a mathematical model of multiplex Ecological Ammensalism with the help of classical RK-method of fourth order in view of reversal dominance time. The mathematical model constitutes of Ammensal-enemy species pair with cover protection for Ammensal species, alternative resources for enemy species and both the species are immigrated. In addition to this, harvesting variable rates are also incorporated. The model is characterized by a couple of first order non linear ordinary differential equations. The relation between the carrying capacity of Ammensal /enemy species with the reversal dominance time is investigated numerically. Some conclusions are derived from the relationships.  AMS Classification: 92 D 25, 92 D 4