Effects of thermal buoyancy and variable thermal conductivity on the MHD flow and heat transfer in a power-law fluid past a vertical stretching sheet in the presence of a non-uniform heat source

The paper considers the flow of a power-law fluid past a vertical stretching sheet. Effects of variable thermal conductivity and non-uniform heat source/sink on the heat transfer are addressed. The thermal conductivity is assumed to vary linearly with temperature. Similarity transformation is used to convert the governing partial differential equations into a set of coupled, non-linear ordinary differential equations. Two different types of boundary heating are considered, namely Prescribed power-law Surface Temperature (PST) and Prescribed power-law Heat Flux (PHF). Shooting method is used to obtain the numerical solution for the resulting boundary value problems. The effects of Chandrasekhar number, Grashof number, Prandtl number, non-uniform heat source/sink parameters, wall temperature parameter and variable thermal conductivity parameter on the dynamics are shown graphically in several plots. The skin friction and heat transfer coefficients are tabulated for a range of values of the parameters. Present study reveals that in a gravity affected flow buoyancy effect has a significant say in the control of flow and heat transfer. © 2008 Elsevier Ltd. All rights reserved

Organizational professionalism in globalizing law firms.

Are the challenges of globalization, technology and competition exercising a dramatic impact on professional practice whilst, in the process, compromising traditional notions of professionalism, autonomy and discretion? This paper engages with these debates and uses original, qualitative empirical data to highlight the vast areas of continuity that exist even the largest globalizing law firms. Whilst it is undoubted that growth in the size of firms and their globalization bring new challenges, these are resolved in ways that are sensitive to professional values and interests. In particular, a commitment to professional autonomy and discretion still characterises the way in which these firms operate and organize themselves. This situation is explained in terms of the development of an organizational model of professionalism, whereby the large organization is increasingly emerging as a primary locus of professionalization and whereby professional priorities and objectives are increasingly supported by organizational logics, systems and initiatives

Gas Chromatography Results Interpretation: Absolute Amounts Versus Relative Percentages

Geneeskunde en GesondheidswetenskappeChemiese PatologiePlease help us populate SUNScholar with the post print version of this article. It can be e-mailed to: [email protected]

Closed-String Tachyons and the Hagedorn Transition in AdS Space

We discuss some aspects of the behaviour of a string gas at the Hagedorn temperature from a Euclidean point of view. Using AdS space as an infrared regulator, the Hagedorn tachyon can be effectively quasi-localized and its dynamics controled by a finite energetic balance. We propose that the off-shell RG flow matches to an Euclidean AdS black hole geometry in a generalization of the string/black-hole correspondence principle. The final stage of the RG flow can be interpreted semiclassically as the growth of a cool black hole in a hotter radiation bath. The end-point of the condensation is the large Euclidean AdS black hole, and the part of spacetime behind the horizon has been removed. In the flat-space limit, holography is manifest by the system creating its own transverse screen at infinity. This leads to an argument, based on the energetics of the system, explaining why the non-supersymmetric type 0A string theory decays into the supersymmetric type IIB vacuum. We also suggest a notion of `boundary entropy', the value of which decreases along the line of flow.Comment: 24 pages, Harvmac. 2 Figures. Typos corrected and reference adde

Bianchi type I space and the stability of inflationary Friedmann-Robertson-Walker space

Stability analysis of the Bianchi type I universe in pure gravity theory is studied in details. We first derive the non-redundant field equation of the system by introducing the generalized Bianchi type I metric. This non-redundant equation reduces to the Friedmann equation in the isotropic limit. It is shown further that any unstable mode of the isotropic perturbation with respect to a de Sitter background is also unstable with respect to anisotropic perturbations. Implications to the choice of physical theories are discussed in details in this paper.Comment: 5 pages, some comment adde

Collider signals from slow decays in supersymmetric models with an intermediate-scale solution to the mu problem

The problem of the origin of the mu parameter in the Minimal Supersymmetric Standard Model can be solved by introducing singlet supermultiplets with non-renormalizable couplings to the ordinary Higgs supermultiplets. The Peccei-Quinn symmetry is broken at a scale which is the geometric mean between the weak scale and the Planck scale, yielding a mu term of the right order of magnitude and an invisible axion. These models also predict one or more singlet fermions which have electroweak-scale masses and suppressed couplings to MSSM states. I consider the case that such a singlet fermion, containing the axino as an admixture, is the lightest supersymmetric particle. I work out the relevant couplings in several of the simplest models of this type, and compute the partial decay widths of the next-to-lightest supersymmetric particle involving leptons or jets. Although these decays will have an average proper decay length which is most likely much larger than a typical collider detector, they can occasionally occur within the detector, providing a striking signal. With a large sample of supersymmetric events, there will be an opportunity to observe these decays, and so gain direct information about physics at very high energy scales.Comment: 24 pages, LaTeX, 4 figure

Higgs Scalars in the Minimal Non-minimal Supersymmetric Standard Model

We consider the simplest and most economic version among the proposed non-minimal supersymmetric models, in which the $\mu$-parameter is promoted to a singlet superfield, whose all self-couplings are absent from the renormalizable superpotential. Such a particularly simple form of the renormalizable superpotential may be enforced by discrete $R$-symmetries which are extended to the gravity-induced non-renormalizable operators as well. We show explicitly that within the supergravity-mediated supersymmetry-breaking scenario, the potentially dangerous divergent tadpoles associated with the presence of the gauge singlet first appear at loop levels higher than 5 and therefore do not destabilize the gauge hierarchy. The model provides a natural explanation for the origin of the $\mu$-term, without suffering from the visible axion or the cosmological domain-wall problem. Focusing on the Higgs sector of this minimal non-minimal supersymmetric standard model, we calculate its effective Higgs potential by integrating out the dominant quantum effects due to stop squarks. We then discuss the phenomenological implications of the Higgs scalars predicted by the theory for the present and future high-energy colliders. In particular, we find that our new minimal non-minimal supersymmetric model can naturally accommodate a relatively light charged Higgs boson, with a mass close to the present experimental lower bound.Comment: 63 pages (12 figures), extended versio

The anomalous Higgs-top couplings in the MSSM

The anomalous couplings of the top quark and the Higgs boson has been studied in an effective theory resulting in the framework of the minimal supersymmetric extension of the standard model (MSSM) when the heavy fields are integrated out. Constraints on the parameters of the model from the experimental data on the ratio $R_b={\Gamma(Z\to b\bar{b})/\Gamma(Z\to hadrons)}$ are derived.Comment: Latex, 26 pages + 13 ps figures, final version in PR

The First Magnetic Fields

We review current ideas on the origin of galactic and extragalactic magnetic fields. We begin by summarizing observations of magnetic fields at cosmological redshifts and on cosmological scales. These observations translate into constraints on the strength and scale magnetic fields must have during the early stages of galaxy formation in order to seed the galactic dynamo. We examine mechanisms for the generation of magnetic fields that operate prior during inflation and during subsequent phase transitions such as electroweak symmetry breaking and the quark-hadron phase transition. The implications of strong primordial magnetic fields for the reionization epoch as well as the first generation of stars is discussed in detail. The exotic, early-Universe mechanisms are contrasted with astrophysical processes that generate fields after recombination. For example, a Biermann-type battery can operate in a proto-galaxy during the early stages of structure formation. Moreover, magnetic fields in either an early generation of stars or active galactic nuclei can be dispersed into the intergalactic medium.Comment: Accepted for publication in Space Science Reviews. Pdf can be also downloaded from http://canopus.cnu.ac.kr/ryu/cosmic-mag1.pd

Wholesale pricing in a small open economy

This paper addresses the empirical analysis of wholesale profit margins using data of the Dutch wholesale sector, 1986. At the heart of the analysis is the typical nature of wholesale production: wholesalers do not produce a tangible product, but offer a service capacity. This has an immediate impact on the identification, interprelation and measurement of determinants of profit variations. A model is set up to explain variations in wholesale profit margins, which is inspired by two widely applied approaches to industry pricing: the behavioural mark-up model and the marginalist price-cost model