The Hydrodynamical Limit of Quantum Hall system

We study the current algebra of FQHE systems in the hydrodynamical limit of small amplitude, long-wavelength fluctuations. We show that the algebra simplifies considerably in this limit. The hamiltonian is expressed in a current-current form and the operators creating inter-Landau level and lowest Landau level collective excitations are identified.Comment: Revtex, 16 page

Single-Symbol ML Decodable Distributed STBCs for Partially-Coherent Cooperative Networks

Space-time block codes (STBCs) that are single-symbol decodable (SSD) in a co-located multiple antenna setting need not be SSD in a distributed cooperative communication setting. A relay network with N relays and a single source-destination pair is called a partially-coherent relay channel (PCRC) if the destination has perfect channel state information (CSI) of all the channels and the relays have only the phase information of the source-to-relay channels. In this paper, first, a new set of necessary and sufficient conditions for a STBC to be SSD for co-located multiple antenna communication is obtained. Then, this is extended to a set of necessary and sufficient conditions for a distributed STBC (DSTBC) to be SSD for a PCRC, by identifying the additional conditions. Using this, several SSD DSTBCs for PCRC are identified among the known classes of STBCs. It is proved that even if a SSD STBC for a co-located MIMO channel does not satisfy the additional conditions for the code to be SSD for a PCRC, single-symbol decoding of it in a PCRC gives full-diversity and only coding gain is lost. It is shown that when a DSTBC is SSD for a PCRC, then arbitrary coordinate interleaving of the in-phase and quadrature-phase components of the variables does not disturb its SSD property for PCRC. Finally, it is shown that the possibility of {\em channel phase compensation} operation at the relay nodes using partial CSI at the relays increases the possible rate of SSD DSTBCs from $\frac{2}{N}$ when the relays do not have CSI to 1/2, which is independent of N

Managerial Action And Resource Advantage Theory: Conceptual Frameworks Emanating From A Positive Theory Of Competition

Purpose – The purpose of this paper is to illustrate that conceptual frameworks developed from a general theory of competition, i.e. resourceadvantage (R-A) theory, can facilitate managerial action. Design/methodology/approach – After a brief overview of resource-advantage (R-A) theory, five conceptual frameworks are developed and offered for the purposes of managerial action. Findings – This paper identifies several conceptual frameworks and after noting that conceptual frameworks that do not have positive theoretical foundations may not be as useful as those that do, develops five conceptual frameworks that are based on R-A theory. Practical implications – The conceptual frameworks developed in this paper have great potential for facilitating managerial action. Originality/value – Conceptual frameworks that have positive theoretical foundations can be very useful for practitioners. In fact, the frameworks proposed in this paper can replace frameworks that are currently in use for managerial action

Teaching Dynamic Competition in Marketing

The purpose of this paper is to illustrate how marketing instructors can prepare students for the real world of dynamic, even hyper-kinetic, competition by teaching resource-advantage (R-A) theory of competition. Accordingly, this paper reviews the problem of marketing students’ lack of preparation for real-world, dynamic competition which is a result of the static-equilibrium focus of the theories of competition that they learn in their economics courses, and shows how the problem can be resolved by exposing students to the dynamic competition of R-A theory. Specifically, we provide answers to five questions concerning pedagogy and R-A theory: (1) Why should students learn about dynamic competition, in general, and R-A theory, in particular? (2) What should students read prior to class? (3) What background information should be discussed? (4) Which figures and tables should be used? (5) What does R-A theory imply for teaching marketing? Overall, in addition to providing students an understanding of dynamic competition, R-A theory “pulls together” theories of marketing strategy. In fact, in graduate and undergraduate marketing strategy classes that use R-A theory, instructors report that they see extensive use by students of R-A theory and the theory’s lexicon, R-A theory’s conceptual frameworks, and central tenets of different forms of marketing strategy

MK Morphological Study of Am Stars at 66 Å/mm

The pseudo-luminosity effect in the metallic line A-type stars found by Abt & Morgan (1976) is confirmed in a random sample of 27 Am stars. From a morphological study of their spectra in the wavelength interval 3850-4400 Å at a reciprocal dispersion of 66 Å/mm, revised spectral types are given on the MK system for their K-line and metallic-line spectra. This shows that: (a) our segregation of weak Am from the Am stars largely agrees with that by Cowleyet al. (1969); (b) all the stars in the sample are dwarfs according to their K-line classification; (c) more than 80 per cent exhibit the pseudo-luminosity effect significantly, with their metallic-line spectra resembling a giant or even a supergiant in the violet (3850-4100 Å), and a giant rather than a dwarf in the blue region (4260-4400 Å); (d) in two-thirds of the stars under (c), the Sr n 4077 Å line is found to have a markedly brighter luminosity class compared to any region, and in more than one-third of the sample it is comparable to that in Ap stars; (e) at least five stars exhibit characteristics which might suggest a spectrum variability: among these, the most striking example is 41 Sex A which was found to show a phase-modulated spectrum variation hitherto unknown in Am stars; (f) the metallic-line spectra of another five stars appear to be similar to A-shell type in differing degrees; (g) less than 20 per cent of the sample comprises stars which do not show any significant differential luminosity effect; these stars might have been misclassified or perhaps they are in a quiescent state. We also confirm the conclusion arrived at by Bohm-Vitense & Johnson (1978) that all Am stars may vary and our observations suggest that groups may exist among them

Effect of Viscous Dissipation, Soret and Dufour Effect on Free Convection Heat and Mass Transfer from Vertical Surface in a Porous Medium

AbstractIn the present approach, a two dimensional steady free convection flow of heat and mass transfer from a vertical surface in porous media with viscous dissipation has been analyzed numerically considering Soret and Dufour effects. The governing non linear partial differential equations have been transformed by a similar transformation in to a system of ordinary differential equations, which are solved numerically by using implicit finite difference scheme. The dimensionless velocity, temperature and concentration profiles are displayed graphically showing the effects for the different values of the Lewis number, soret number and viscous dissipation parameter

Process control & instrumentation for titanium sponge plant

A large scale facility for establishing the technology of production of titanium sponge in 4000 kg batches by high temperature reduction of titanium tetrachloride has been set up at the Defence Metallurgical Research Laboratory, Hyderabad. The steps involved in the process are (i) two stage distillation for the purification of titanium tetrachloride (ii) high temperature reduction of titanium tetrachloride by molten magnesium followed by pyro-vacuum distillation of sponge in a combined reductionvacuum disti-llation furnace and (iii) processing of the sponge produ-ced which include sponge ejection, cutting, crushing and blending. To produce high purity sponge in a reproducible manner batch after batch, very close monitoring & control of process parameters is essential. In view of the highly reactive nature of the metal, any post reduction purifica-tion is totally ruled out. This paper discusses in detail the process control scheme adopted for the titanium tetra-chloride purification and reduction operations, highlight-ing the type of instrumentation adopted considering the corrosive nature of titanium tetrachloride. A microproce-ssor based Distributed Control System has been installed for controlling the process operation. Salient features of this system are also described in this paper

Image Denoising by using Modified SGHP Algorithm

In real time applications, image denoising is a predominant task. This task makes adequate preparation for images looks prominent. But there are several denoising algorithms and every algorithm has its own distinctive attribute based upon different natural images. In this paper, we proposed a perspective that is modified parameter in S-Gradient Histogram Preservation denoising method. S-Gradient Histogram Preservation is a method to compute the structure gradient histogram from the noisy observation by taking different noise standard deviations of different images. The performance of this method is enumerated in terms of peak signal to noise ratio and structural similarity index of a particular image. In this paper, mainly focus on peak signal to noise ratio, structural similarity index, noise estimation and a measure of structure gradient histogram of a given image