Interdiffusion study on Co(W) solid solution and topological close-packed mu phase in Co-W system

An interdiffusion study is conducted on the Co-W system by a diffusion couple technique. The interdiffusion coefficient of the Co(W) solid solution and the Co7W6 mu phase is determined. The activation energy is found to increase with the W content of the Co(W) solid solution. (C) 2010 Elsevier Ltd. All rights reserved.

A Case Study in Matching Service Descriptions to Implementations in an Existing System

A number of companies are trying to migrate large monolithic software systems to Service Oriented Architectures. A common approach to do this is to first identify and describe desired services (i.e., create a model), and then to locate portions of code within the existing system that implement the described services. In this paper we describe a detailed case study we undertook to match a model to an open-source business application. We describe the systematic methodology we used, the results of the exercise, as well as several observations that throw light on the nature of this problem. We also suggest and validate heuristics that are likely to be useful in partially automating the process of matching service descriptions to implementations.

Characterization of an in vitro transcription system from rinderpest virus

An in vitro transcription system for rinderpest virus (RPV) is described. Ribonucleoprotein complexes isolated from RPV-infected Vero cells, human lung carcinoma cells, or detergent-disrupted purified virions synthesized authentic RPV mRNAs for the N, P, M, F and H genes as identified by dot blot hybridization analysis with individual cDNA clones. The relative abundance of the mRNAs synthesized in vitro decreased from the 3? end of the genome to the 5? end, very similar to that observed with measles virus transcription in vitro. The transcription by purified virions was stimulated three-fold by the addition of infected human lung carcinoma cell lysate, demonstrating the involvement of host factor(s) in mRNA synthesis.

Noise-spike-induced escape in a bistable system driven by colored noise: Noise with long correlation times

An escape mechanism in a bistable system driven by colored noise of large but finite correlation time (tau) is analyzed. It is shown that the fluctuating potential theory [Phys. Rev. A 38, 3749 (1988)] becomes invalid in a region around the inflection points of the bistable potential, resulting in the underestimation of the mean first passage time at finite tau by this theory. It is shown that transitions at large but finite tau are caused by noise spikes, with edges rising and falling exponentially in a time of O(tau). Simulation of the dynamics of the bistable system driven by noise spikes of the above-mentioned nature clearly reveal the physical mechanism behind the transition.

Role of zirconium addition on stability of UAl3 phase in Al-U system

The microstructural changes of Al-22 wt%U and Al-46 wt%U alloys containing 3 wt% Zr were investigated after heat treatment at 620 degrees C for 1 to 45 days, Though it is reported that addition of similar to 3 wt% Zr stabilizes the (U,Zr)Al-3 phase at room temperature, the present investigation shows that the (U,Zr)Al-3 phase is not stable but slowly transforms to the U0.9Al4 phase, The high temperature creep curves generated for these ternary alloys showed a wavy pattern which also suggests that the (U,Zr)Al-3 phase is not stable.

On the explicit determination of the polar decomposition in n-dimensional vector spaces

A method for the explicit determination of the polar decomposition (and the related problem of finding tensor square roots) when the underlying vector space dimension n is arbitrary (but finite), is proposed. The method uses the spectral resolution, and avoids the determination of eigenvectors when the tensor is invertible. For any given dimension n, an appropriately constructed van der Monde matrix is shown to play a key role in the construction of each of the component matrices (and their inverses) in the polar decomposition.

Axial wave propagation in coupled nanorod system with nonlocal small scale effects

This article deals with the axial wave propagation properties of a coupled nanorod system with consideration of small scale effects. The nonlocal elasticity theory has been incorporated into classical rod/bar model to capture unique features of the coupled nanorods under the umbrella of continuum mechanics theory. Nonlocal rod model is developed for coupled nanorods. The strong effect of the nonlocal scale has been obtained which leads to substantially different wave behavior of nanorods from those of macroscopic rods. Explicit expressions are derived for wavenumber, cut-off frequency and escape frequency of nanorods. The analysis shows that the wave characteristics of nanorods are highly over estimated by the classical rod model, which ignores the effect of small-length scale. The studies also shows that the nonlocal scale parameter introduces certain band gap region in axial or longitudinal wave mode, where no wave propagation occurs. This is manifested in the spectrum cures as the region, where the wavenumber tends to infinite or wave speed tends to zero. The effect of the coupled spring stiffness is also capture in the present analysis. It has been also shown that the cut-off frequency increases as the stiffness of the coupled spring increases and also the coupled spring stiffness has no effect on escape frequency of the axial wave mode in the nanorod. This cut-off frequency is also independent of the nonlocal small scale parameter. The present study may bring in helpful insights while investigating multiple-nanorod-system-models for future nano-optomechanical systems applications. The results can also provide useful guidance for the study and design of the next generation of nanodevices that make use of the wave propagation properties of coupled single-walled carbon nanotubes or coupled nanorods. (C) 2011 Elsevier Ltd. All rights reserved.

Quality Assurance and Assessment in Technical Education System: A Web Based Approach

Engineering education quality embraces the activities through which a technical institution satisfies itself that the quality of education it provides and standards it has set are appropriate and are being maintained. There is a need to develop a standardised approach to most aspects of quality assurance for engineering programmes which is sufficiently well defined to be accepted for all assessments.We have designed a Technical Educational Quality Assurance and Assessment (TEQ-AA) System, which makes use of the information on the web and analyzes the standards of the institution. With the standards as anchors for definition, the institution is clearer about its present in order to plan better for its future and enhancing the level of educational quality.The system has been tested and implemented on the technical educational Institutions in the Karnataka State which usually host their web pages for commercially advertising their technical education programs and their Institution objectives, policies, etc., for commercialization and for better reach-out to the students and faculty. This helps in assisting the students in selecting an institution for study and to assist in employment.

Adaptive control of vibration transmission in a strut system

In this article, theoretical and the experimental studies are reported on the adaptive control of vibration transmission in a strut system subjected to a longitudinal pulse train excitation. In the control scheme, a magneto-strictive actuator is employed at the downstream transmission point in the secondary path. The actuator dynamics is taken into account. The system boundary parameters are first estimated off-line, and later employed to simulate the system dynamics. A Delayed-X Filtered-E spectral algorithm is proposed and implemented in real time. The underlying mechanics based filter construction allows for the time varying system dynamics to be taken into account. This work should be of interest for active control of vibration and noise transmission in helicopter gearbox support struts and other systems.

Effect of convection and viscoelasticity on spinodal decomposition in fluids

Current analytical work on the effect of convection and viscoelasticity on the early and late stages of spinodal decomposition is briefly described. In the early stages, the effect of viscoelastic stresses was analysed using a simple Maxwell model for the stress, which was incorporated in the Langevin equation for the momentum field. The viscoelastic stresses are found to enhance the rate of decomposition. In the late stages, the pattern formed depends on the relative composition of the two species. Droplet spinodal decomposition occurs when the concentration of one of the species is small. Convective transport does not have a significant effect on the growth of a single droplet, but it does result in an attractive interaction between non - Brownian droplets which could lead to coalescence. The effect of convective transport for the growth of random interfaces in a near symmetric quench was analysed using an 'area distribution function', which gives the distribution of surface area of the interface in curvature space. It was found that the curvature of the interface decreases proportional to t in the late stages of spinodal decomposition, and the surface area also decreases proportional to t.

Modeling of Ascending/Descending Velocity of Metal Droplet Emulsified in Pb-Salt System

Metal-slag emulsion is an important process to enhance the reaction rate between the two phases; thus, it improves the heat and mass transfer of the process significantly. Various experimental studies have been carried out, and some system specific relations have been proposed by various investigators. A unified, theoretical study is lacking to model this complex phenomenon. Therefore, two simple models based on fundamental laws for metal droplet velocity (both ascending and descending) and bubble velocity, as well as its position at any instant of time, have been proposed. Analytical solutions have been obtained for the developed equations. Analytical solutions have been verified for the droplet velocity, traveling time, and size distribution in slag phase by performing high-temperature experiments in a Pb-salt system and comparing the obtained data with theory. The proposed model has also been verified with published experimental data for various liquid systems with a wide range of physical properties. A good agreement has been found between the analytical solution and the experimental and published data in all cases.

Establishment of an in vitro transcription system for Peste des petits ruminant virus

Background: Peste-des-petits ruminants virus (PPRV) is a non segmented negative strand RNA virus of the genus Morbillivirus within Paramyxoviridae family. Negative strand RNA viruses are known to carry nucleocapsid (N) protein, phospho (P) protein and RNA polymerase (L protein) packaged within the virion which possess all activities required for transcription, post-transcriptional modification of mRNA and replication. In order to understand the mechanism of transcription and replication of the virus, an in vitro transcription reconstitution system is required. In the present work, an in vitro transcription system has been developed with ribonucleoprotein (RNP) complex purified from virus infected cells as well as partially purified recombinant polymerase (L-P) complex from insect cells along with N-RNA (genomic RNA encapsidated by N protein) template isolated from virus infected cells. Results: RNP complex isolated from virus infected cells and recombinant L-P complex purified from insect cells was used to reconstitute transcription on N-RNA template. The requirement for this transcription reconstitution has been defined. Transcription of viral genes in the in vitro system was confirmed by PCR amplification of cDNAs corresponding to individual transcripts using gene specific primers. In order to measure the relative expression level of viral transcripts, real time PCR analysis was carried out. qPCR analysis of the transcription products made in vitro showed a gradient of polarity of transcription from 3' end to 5' end of the genome similar to that exhibited by the virus in infected cells. Conclusion: This report describes for the first time, the development of an in vitro transcription reconstitution system for PPRV with RNP complex purified from infected cells and recombinant L-P complex expressed in insect cells. Both the complexes were able to synthesize all the mRNA species in vitro, exhibiting a gradient of polarity in transcription.