The Electronic Structure of Graphite from Compton Profile Measurements

Compton profile data are used to investigate the ground state wavefunction of graphite. The results of two new $\gamma$-ray measurements are reported and compared with the results of earlier $\gamma$-ray and electron scattering measurements. A tight-binding calculation has been carried out and the results of earlier calculations based on a molecular model and a pseudo-potential wavefunction are considered. The analysis, in terms of the reciprocal form factor, shows that none of the calculations gives an adequate description of the data in the basal plane although the pseudo-potential calculation describes the anisotropy in the plane reasonably well. In the basal plane the zero-crossing theorem appears to be violated and this problem must be resolved before more accurate models can be derived. In the c-axis direction the molecular model and the tight binding calculation give better agreement with the experimental data than does the pseudopotential calculation.

The structure of turbulent boundary layers along mildly curved surfaces

This paper describes a detailed study of the structure of turbulence in boundary layers along mildly curved convex and concave surfaces. The surface curvature studied corresponds to δ/Rw = ± 0·01, δ being the boundary-layer thickness and Rw the radius of curvature of the wall, taken as positive for convex and negative for concave curvature. Measurements of turbulent energy balance, autocorrelations, auto- and cross-power spectra, amplitude probability distributions and conditional correlations are reported. It is observed that even mild curvature has very strong effects on the various aspects of the turbulent structure. For example, convex curvature suppresses the diffusion of turbulent energy away from the wall, reduces drastically the integral time scales and shifts the spectral distributions of turbulent energy and Reynolds shear stress towards high wavenumbers. Exactly opposite effects, though generally of a smaller magnitude, are produced by concave wall curvature. It is also found that curvature of either sign affects the v fluctuations more strongly than the u fluctuations and that curvature effects are more significant in the outer region of the boundary layer than in the region close to the wall. The data on the conditional correlations are used to study, in detail, the mechanism of turbulent transport in curved boundary layers. (Published Online April 12 2006)

Arts, gentrification, and planning for creativity

Recent decades have seen an almost obsessive focus on creativity in an urban development context. Yet, creativity has come to be prized not so much for the intrinsic values of imagination, innovation and experimentation as for the possibility to exploit these qualities as a means of urban revitalization and wealth generation. This policy emphasis has both contributed to the misplaced assumption that artistic activity causes gentrification and displacement while, at the same time, often setting in motion programs that are detrimental to the creative environments such policies claim to support. It is time to end the current approach to creative city planning, which treats the arts as amenities to catalyze land development and lure upscale consumption.

Effect of compatibilization on mechanical and thermal properties of polypropylene–soy flour composites

A new biobased composite was developed by adding soy flour (SF) to polypropylene (PP). This composite shows an enhanced tensile strength and modulus but decrease in elongation at break. The compatibilizer (coupling agent) appears to have a synergistic effect on tensile strength. The presence of the compatibilizer improves the dispersion of SF in the PP matrix. The addition of glycerol plasticizer to the composite improves the processability resulting in improved performance, as compared to composites without glycerol plasticizer. The optimal compatibilizer content appears to be 6%.

Control aspects in proportionality Markov manpower systems

In this paper, the control aspects of a hierarchical organization under the influence of "proportionality" policies are analyzed. Proportionality policies are those that restrict the recruitment to every level of the hierarchy (except the bottom most level or base level) to be in strict proportion to the promotions into that level. Both long term and short term control analysis have been discussed. In long term control the specific roles of the parameters of the system with regard to control of the shape and size of the system have been analyzed and yield suitable control strategies. In short term control, the attainability of a target or goal structure within a specific time from a given initial structure has been analyzed and yields the required recruitment strategies. The theoretical analyses have been illustrated with computational examples and also with real world data.

Control aspects in proportionality Markov manpower systems

In this paper, the control aspects of a hierarchical organization under the influence of "proportionality" policies are analyzed. Proportionality policies are those that restrict the recruitment to every level of the hierarchy (except the bottom most level or base level) to be in strict proportion to the promotions into that level. Both long term and short term control analysis have been discussed. In long term control the specific roles of the parameters of the system with regard to control of the shape and size of the system have been analyzed and yield suitable control strategies. In short term control, the attainability of a target or goal structure within a specific time from a given initial structure has been analyzed and yields the required recruitment strategies. The theoretical analyses have been illustrated with computational examples and also with real world data. The control of such proportionality systems is then compared with that of the general systems (which do not follow such policies) with some significant conclusions. The control relations of such proportionality systems are found to be simpler and more practically feasible than those of general Markov systems, which do not have such restrictions. Such proportionality systems thus not only retain and match the flexibility of general Markov systems but also have the added advantage of simpler and more practically feasible controls. The proportionality policies hence act as an alternative and more practicably feasible means of control. (C) 2004 Elsevier Inc. All rights reserved.

Mechanical and Thermal Properties of Eva Blended with Biodegradable Ethyl Cellulose

In this study, biodegradable blend of Poly (Ethylene-co-Vinyl Acetate) (EVA) and Ethyl Cellulose (EC) were prepared. Ethylene vinyl alcohol (EVOH) copolymer was used as an interfacial compatibilizer to enhance adhesion between EVA and EC. The melt blended compatibilized biocomposites were examined for mechanical and thermal properties as per the ASTM standards. It has been found that the EC has a reinforcing effect on EVA leading to enhanced tensile strength and also impart biodegradability. Thus, a high loading of 50% EC could be added without compromising Much on the mechanical properties. Analysis of the tensile data using predictive theories showed an enhanced interaction of the dispersed phase (EC) and the matrix (EVA). The compatibilizing effects of EVOH on these blends were confirmed by the significant improvement in the mechanical properties comparable with neat EVA as also observed by SEM microscopy. The TGA thermograms exhibits two-stage degradation and as EC content increases, the onset temperature for thermal degradation reduces. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 116: 1044-1056, 2010

A molecular dynamics study of a PbO.SiO2 glass and melt

The structures of a PbO.SiO2 glass and melt have been studied using molecular dynamics simulation employing Born-Mayer-Huggins pair potentials. Various pair distribution functions are presented and discussed. Pb-Pb correlations persist in the melt, in agreement with experimental observations. The calculated and experimental radial distribution functions are compared.

Structured systems methodology for evaluation of random interruptions in continuous process type manufacturing systems

A structured systems methodology was developed to analyse the problems of production interruptions occurring at random intervals in continuous process type manufacturing systems. At a macro level the methodology focuses on identifying suitable investment policies to reduce interruptions of a total manufacturing system that is a combination of several process plants. An interruption-tree-based simulation model was developed for macroanalysis. At a micro level the methodology focuses on finding the effects of alternative configurations of individual process plants on the overall system performance. A Markov simulation model was developed for microlevel analysis. The methodology was tested with an industry-specific application.

Deviation from 3-D Ising critical behaviour in aqueous electrolyte solutions

The near-critical behaviour in complex fluids, comprising electrolyte solutions, polymer solutions and amphiphilic systems, reveals a marked departure from the 3-D Ising behaviour. This departure manifests itself either in terms of a crossover from Ising to mean-field (or classical) critical behaviour, when moving away from a given critical point (Tc), or by the persistence of only mean-field region in the surprisingly close vicinity of Tc. The ilo,non-Ising features of the osmotic compressibility (chi(T,p)) in solutions of electrolytes, that exhibit orle or many liquid-liquid transitions, will be presented. The underlying cause of the breakdown of the anticipated 3-D Ising behaviour in aqueous electrolyte solutions is traced to the structuring induced by the electrolytes. New evidence constituting, measurements of small-angle X-ray scattering (SAXS) and the excess molar volume, is advanced to support the thesis of the close relationship, between the structuring and the deviation from the 3-D Ising critical behaviour in aqueous electrolyte solutions.