Active damping of piezo-composite beams

The aim of the present study is to investigate the effects of piezoceramic materials on the active damping of vibrating piezo-composite beams. The active damping is obtained by using an actuator and a sensor piezoceramic layer acting in ‘closed-loop’. By transferring the accumulated voltage on the sensor layer to the piezoelectric actuator layer, the beam can actively damp-out its vibrations. An exact mathematical model, based on a first order shear deformation theory (FSDT) is developed and described. This model allows the investigation of piezo-composite beams with two actuation/sensing type mechanisms, extension and shear. The present study is confined to symmetric lay-up beams using continuous piezoelectric layers. Using the present model, both natural and damped vibrations are calculated. The effects of the feedback gain, G, and the beam length on the damped vibrations are investigated and presented.     

Understanding and countering chronic processes with mental patients: An interpersonal model.

Presents a broad-focus model for conceptualizing and treating chronic processes with psychiatric patients that integrates behavioral social-competence approaches and systemic-interactive ones. The events that originate and sustain dysfunctional behaviors involve a cycle of repetitive failure, rejection and hurt, self-isolation and segregation by others, mutual guilt and anger, psychiatric labeling, and giving up. The rehabilitation center in which the mapping of and training in social competences occurs serves as the context for systemic interactions that counter these chronic processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Detection of non-topological motifs in protein structures

We present an efficient technique for the comparison of proteinstructures. The algorithm uses a vector representation of thesecondary structure elements and searches for spatial configurationsof secondary structure elements in proteins. In such recurringprotein folds, the order of the secondary structure elementsin the protein chains is disregarded. The method is based onthe geometric hashing paradigm and implements approaches originatingin computer vision. It represents and matches the secondarystructure element vectors in a 3-D translation and rotationinvariant manner. The matching of a pair of proteins takes onaverage under 3 s on a Silicon Graphics Indigo2 workstation,allowing extensive all-against-all comparisons of the data setof non-redundant protein structures. Here we have carried outsuch a comparison for a data set of over 500 protein molecules.The detection of recurring topological and non-topological,secondary structure element order-independent protein foldsmay provide further insight into evolution. Moreover, as theserecurring folding units are likely to be conformationalHy favourable,the availability of a data set of such topological motifs canserve as a rich input for threading routines. Below, we describethis rapid technique and the results it has obtained. Whilesome of the obtained matches conserve the order of the secondarystructure elements, others are entirely order independent. Asan example, we focus on the results obtained for Che Y, a signaltransduction protein, and on the profilin-ß-actincomplex. The Che Y molecule is composed of a five-stranded,parallel ß-sheet flanked by five helices. Here weshow its similarity with the Escherichia coli elongation factor,with L-arabinose binding protein, with haloalkane dehalogenaseand with adenylate kinase. The profilin–ß-actincontains an antiparallel ß-pleated sheet with -helicaltermini. Its similarities to lipase, fructose disphosphataseand ß-lactamase are displayed.     

Long-range hydrodynamic response of particulate liquids and liquid-laden solids

In viscous particulate liquids, such as suspensions and polymer solutions, the large-distance steady-state flow due to a local disturbance is commonly described in terms of hydrodynamic screening—beyond a correlation length ξ the response drops from that of the pure solvent, characterized by its viscosity η₀, to that of the macroscopic liquid with viscosity η > η₀ For cases where η >> η₀ we show, based on general conservation arguments, that this screening picture, while being asymptotically correct, should be refined in an essential way. The crossover between the microscopic and macroscopic behaviors occurs gradually over a wide range of distances, ξ < r < (η / η₀)^1/2 ξ In liquid-laden solids, such as colloidal glasses, gels, and liquid-filled porous media, where η → ∞, this intermediate behavior takes over the entire large-distance response. The intermediate flow field, arising from the effect of mass displacement rather than momentum diffusion, has several unique characteristics: (i) It has a dipolar shape with l/r ³ spatial decay, negative transverse components, and vanishing angular average. (ii) Its amplitude depends on the liquid properties through η₀ and ξ alone; thus, in cases where ξ is fixed by geometry (e.g., for particulate liquids tightly confined in solid matrices), the large-distance response is independent of particle concentration. (iii) The intermediate field builds up non-diffusively, with a distance-independent relaxation rate, making it dominant at large distances before steady state has been reached. We demonstrate these general properties in three model systems.     

Rethinking cities in the Middle East: political economy, planning, and the lived space

Urbanisation is an economic, political, and socio-cultural complexity, and so is its interaction with cityscapes. However, this truism rarely finds an expression in academic research. It is obvious that economic transitions would determine the quality and volume of the built environment. Municipal and state decision making further shape the nature of urban spaces, and socio-cultural transformations influence perceived notions of the lived space and, in turn, reshape the physical landscape itself. Nevertheless, research on cities in the Middle East and elsewhere remains fairly limited in scope, with little cross-discipline 'conversation' among scholars in different fields which attempts to account for such complexity. This is all the more surprising as life in cities has become, over the past half century or so, the most significant form of human collective dwelling; in the Middle East over half the population currently lives in urban settings and the numbers are forecast to grow in the future.1

This review article is the result of a dialogue between an architect and an economic historian in response to the foregoing. We have united in an attempt to offer a more integrative approach to Middle East urbanism, accounting for the interactions of the political economy of this region, planning, and the lived space. The key questions on which we focus are why and how do state transformation and economic structural change impact upon urban space. In seeking the answers we examine the long-term trajectory of cities as they went through the first period of globalisation under imperial intervention and/or direct colonial rule; gradually came under independent, inward-looking, national regimes; and presently experience the second wave of globalisation and the opening of local economies to international markets. Such a narrative explores common themes in the historical trajectories of cities' lives.

Our long-term, geographically extensive overview (Map 1) is bound to miss some specific developments that have made a significant impact on the transformations of cities in the region; our aim is not to totalise Middle East experiences and reduce a variety of narratives to a simplistic linear model of change. Even more so, our study of the Middle East is mostly focused on Egypt, the Asian Arab countries (the mashraq), Israel/Palestine, and Turkey, the geographical unit which roughly corresponded with the Ottoman Empire, the last state to control the Middle East before the age of nations. We acknowledge that any bird's eye view perspective is bound to do some injustice to historically specific contexts, and city transitions that occurred in such contexts. We would welcome any future work that brings our suggestion here, namely to integrate political economy with the study of urban development and city life, to bear on more specific research on urbanism in the Middle East.     

Experimental Investigation of Convective Heat Transfer Between Silicon-Melt and Solidification Front

Convective heat transfer between silicon melt and solidification front during Bridgman-type solidification process in a ceramic crucible has been investigated by means of heat balance analysis of the crucible during the process. The effect of aspect ratio on the Rayleigh and Nusselt numbers has been investigated. For a large crucible size (with inner diameter of about 0.50-m), the dependence correlates well with the empiric formula Nu?=?0.303 Ra^0.279. For a small crucible size (with inner diameter of about 0.20-m), the dependence correlates well with the empiric formula Nu?=?0.181 Ra^0.285. The experimental data obtained were compared with the available literature experimental and numerical simulation data.

     

General control charts for attributes

Traditional Shewhart-type control charts ignore the skewness of the plotted statistic. Occasionally, the skewness is too large to be ignored, and in such cases the classical Shewhart chart ceases to deliver satisfactory performance. In this paper, we develop a general framework for constructing Shewhart-like control charts for attributes based on fitting a quantile function that preserves all first three moments of the plotted statistic. Furthermore, these moments enter explicitly into the formulae for calculating the limits. To enhance the accuracy of these limits the value of the skewness measure used in the calculations is inflated by 44%. This inflation rate delivers accurate control limits for diversely-shaped attribute distributions like the binomial, the Poisson, the geometric and the negative binomial. A new control chart for the M/M/S queueing model is developed and its performance evaluated.