ANALYSIS OF THIN PLATES IN BENDING BY NEW RECTANGULAR STRAIN BASED ELEMENT.

Abstract This paper deals with the development of a new simple four node rectangular finite element for bending analysis of thin plates. The displacement s field of this element is based on the assumed functions for the various strains satisfying the compatibility equations. This developed element has three degrees of freedom at each node (two rotations and one translation), and it passed successfully benchmark tests in the case of thin plates without shear locking phenomena. The obtained numerical results using the developed element converge toward both analytical and reference solutions

Influence of impreciseness in designing tritrophic level complex food chain modeling in interval environment

Abstract In this paper, we construct a tritrophic level food chain model considering the model parameters as fuzzy interval numbers. We check the positivity and boundedness of solutions of the model system and find out all the equilibrium points of the model system along with its existence criteria. We perform stability analysis at all equilibrium points of the model system and discuss in the imprecise environment. We also perform meticulous numerical simulations to study the dynamical behavior of the model system in detail. Finally, we incorporate different harvesting scenarios in the model system and deploy maximum sustainable yield (MSY) policies to determine optimum level of harvesting in the imprecise environment without putting any unnecessary extra risk on the species toward its possible extinction

The evolution of Balmer jump selected galaxies in the ALHAMBRA survey

We present a new color-selection technique, based on the Bruzual & Charlot models convolved with the bands of the ALHAMBRA survey, and the redshifted position of the Balmer jump to select star-forming galaxies in the redshift range 0.5 < z < 1.5. These galaxies are dubbed Balmer jump Galaxies BJGs. We apply the iSEDfit Bayesian approach to fit each detailed SED and determine star-formation rate (SFR), stellar mass, age and absolute magnitudes. The mass of the haloes where these samples reside are found via a clustering analysis. Five volume-limited BJG sub-samples with different mean redshifts are found to reside in haloes of median masses $\sim 10^{12.5 \pm 0.2} M_\odot$ slightly increasing toward z=0.5. This increment is similar to numerical simulations results which suggests that we are tracing the evolution of an evolving population of haloes as they grow to reach a mass of $\sim 10^{12.7 \pm 0.1} M_\odot$ at z=0.5. The likely progenitors of our samples at z$\sim$3 are Lyman Break Galaxies, which at z$\sim$2 would evolve into star-forming BzK galaxies, and their descendants in the local Universe are elliptical galaxies.Hence, this allows us to follow the putative evolution of the SFR, stellar mass and age of these galaxies. From z$\sim$1.0 to z$\sim$0.5, the stellar mass of the volume limited BJG samples nearly does not change with redshift, suggesting that major mergers play a minor role on the evolution of these galaxies. The SFR evolution accounts for the small variations of stellar mass, suggesting that star formation and possible minor mergers are the main channels of mass assembly.Comment: 14 pages, 10 figures. Submitted to A&A. It includes first referee's comments. Abstract abridged due to arXiv requirement

Spontaneous Meta-Arithmetic as the First Step Toward School Algebra

Taking as a point of departure the vision of school algebra as a formalized meta-discourse of arithmetic, we have been following six pairs of 7th-grade students (12-13 years old) as they gradually modify their spontaneous meta-arithmetic toward the “official” algebraic form of talk. In this paper we take a look at the very beginning of this process. Preliminary analyses of data have shown, unsurprisingly, that while reflecting on arithmetic processes and relations, the uninitiated 7th graders were employing colloquial means, which could not protect them against occasional ambiguities. More unexpectedly, this spontaneous meta-arithmetic, although not supported by any previous algebraic schooling, displayed some algebra-like features, not to be normally found in everyday discourses

The Final Merger of Black-Hole Binaries

Recent breakthroughs in the field of numerical relativity have led to dramatic progress in understanding the predictions of General Relativity for the dynamical interactions of two black holes in the regime of very strong gravitational fields. Such black-hole binaries are important astrophysical systems and are a key target of current and developing gravitational-wave detectors. The waveform signature of strong gravitational radiation emitted as the black holes fall together and merge provides a clear observable record of the process. After decades of slow progress, these mergers and the gravitational-wave signals they generate can now be routinely calculated using the methods of numerical relativity. We review recent advances in understanding the predicted physics of events and the consequent radiation, and discuss some of the impacts this new knowledge is having in various areas of astrophysics.Comment: 57 pages; 9 figures. Updated references & fixed typos. Published version is at http://www.annualreviews.org/doi/abs/10.1146/annurev.nucl.010909.08324

The Mathematical Facts Of Games Of Chance Between Exposure, Teaching, And Contribution To Cognitive Therapies: Principles Of An Optimal Mathematical Intervention For Responsible Gambling

On the question of whether gambling behavior can be changed as result of teaching gamblers the mathematics of gambling, past studies have yielded contradictory results, and a clear conclusion has not yet been drawn. In this paper, I bring some criticisms to the empirical studies that tended to answer no to this hypothesis, regarding the sampling and laboratory testing, and I argue that an optimal mathematical scholastic intervention with the objective of preventing problem gambling is possible, by providing the principles that would optimize the structure and content of the teaching module. Given the ethical aspects of the exposure of mathematical facts behind games of chance, and starting from the slots case – where the parametric design is missing, we have to draw a line between ethical and optional information with respect to the mathematical content provided by a scholastic intervention. Arguing for the role of mathematics in problem-gambling prevention and treatment, interdisciplinary research directions are drawn toward implementing an optimal mathematical module in cognitive therapies

Shape evolution of electrodeposited bumps with deep cavity

Electrodeposited bumps are the indispensable microconnectors for high-density interconnection in the latest microelectronics applications. The deep cavities are especially important for the solder bumps for ball grid arrays. This investigation discusses the relation between cavity shapes and current distributions of deep cavities. The role of convection and diffusion within the cavities is calculated at diffusion-limited overpotentials with numerical fluid dynamics computations. The current distributions become symmetric and peak profiles become sharper for the deeper cavities of large aspect ratios and of negative photoresist angles, theta. For 30 mu m cathode length, the current at the center is larger than that at the edges for photoresist angles of theta less than or equal to 0. For these deep cavities, the convection outside the cavity is not related to the current distribution and the current distribution is determined by the cavity shape. The mass transport within the deep cavities is controlled mainly by diffusion. This is because the convection outside the cavities is not effectively stirring inside the deep cavities.</p

Emerging technologies in physics education

Three emerging technologies in physics education are evaluated from the interdisciplinary perspective of cognitive science and physics education research. The technologies - Physlet Physics, the Andes Intelligent Tutoring System (ITS), and Microcomputer-Based Laboratory (MBL) Tools - are assessed particularly in terms of their potential at promoting conceptual change, developing expert-like problem-solving skills, and achieving the goals of the traditional physics laboratory. Pedagogical methods to maximize the potential of each educational technology are suggested.Comment: Accepted for publication in the Journal of Science Education and Technology; 20 page

Mesoscale heat waves induced by orography

Abstract. This work is devoted to the analysis of an unusual and sudden thermal fluctuation that interested portions of Friuli Venezia Giulia (Italy) during the night of 27 July 1983. The whole 1983 summer was extremely warm in Europe and in particular on the Italian peninsula, from the Alps down to Sicily. Nevertheless, the day of 27 July 1983 in Friuli Venezia Giulia deserves special attention because the observed maximum temperatures did not occur during day-time but during night-time (from 23:00 up to 24:00 LT, 21:00–22:00 UTC). Peaks of 34.8°C and values of relative humidity of the order of 28% were registered by the official network of weather stations. This event interested mainly the central-eastern part of the plain of Friuli Venezia Giulia, a few kilometers far from the Slovenian border and relieves. The thermal anomalies lasted up to an hour, then temperatures decreased toward values more usual for the climate of the month. The study of this event is carried out with the aid of the AR-WRF numerical atmospheric model, initialized through the ECMWF analysis. The numerical simulations highlight the important role played by orography, jointly with the peculiar thermal structure of the atmosphere, for the enhancing of the internal wave pattern over that area. According to the sensitivity studies realized, the amplification of the internal wave pattern might represent a possible explanation for that meteorological enigma