Institution
Simón Bolívar University
Education•Caracas, Venezuela•
About: Simón Bolívar University is a education organization based out in Caracas, Venezuela. It is known for research contribution in the topics: Population & Crystallization. The organization has 5912 authors who have published 8294 publications receiving 126152 citations.
Topics: Population, Crystallization, Nucleation, Differential scanning calorimetry, Context (language use)
Papers published on a yearly basis
Papers
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TL;DR: In this article, a mixture of isotactic polypropylene, PP and atactic polystyrene (PS) was used to study the nucleation mechanism of immiscible melt mixed blends of a crystallisable polyolefin (isotactic PP) and PS in a wide composition range.
Abstract: Immiscible melt mixed blends of a crystallisable polyolefin (isotactic polypropylene, PP) and atactic polystyrene (PS) were prepared in a wide composition range. It was found that when PP is the major component in the blend its crystallisation behaviour is not affected by blending it with PS. However if PP is the minor component, it will be dispersed in the immiscible PS matrix, hence the nucleation mechanism changes from predominantly heterogeneous to predominantly homogeneous as long as the size of the dispersed PP droplets is below a critical value (of the order of 1–2 μm).
109 citations
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TL;DR: In this paper, the authors employ the gravitational decoupling approach for static and spherically symmetric systems to develop a simple and powerful method in order to continuously isotropize any anisotropic solution of the Einstein field equations, and generate new solutions for self-gravitating distributions with the same or vanishing complexity factor.
Abstract: We employ the gravitational decoupling approach for static and spherically symmetric systems to develop a simple and powerful method in order to (a) continuously isotropize any anisotropic solution of the Einstein field equations, and (b) generate new solutions for self-gravitating distributions with the same or vanishing complexity factor. A few working examples are given for illustrative purposes.
108 citations
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TL;DR: In this paper, the authors find closed-form expressions for the Kirchhoff index of certain connected graphs using Foster's theorems, random walks, and the superposition principle.
Abstract: We find closed-form expressions for the resistance, or Kirchhoff index, of certain connected graphs using Foster's theorems, random walks, and the superposition principle. © 2001 John Wiley & Sons, Inc. Int J Quant Chem 81: 135–140, 2001
108 citations
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TL;DR: Results show that these types of variable fidelity RSAs can be effectively managed by the trust region model management strategy to drive convergence of MDO problems and the CSSO based sampling strategy was found to be, in general, more efficient in driving the optimization.
Abstract: The dimensionality and complexity of typical multidisciplinary systems hinders the use of formal optimization techniques in application to this class of problems. The use of approximations to represent the system design metrics and constraints has become vital for achieving good performance in many multidisciplinary design optimization (MDO) algorithms. This paper reports recent research efforts on the use of variable fidelity response surface approximations (RSA) to drive the convergence of MDO problems using a trust region model management algorithm. The present study focuses on a comparative study of different response sampling strategies based on design of experiment (DOE) approaches within the disciplines to generate the zero order data to build the RSAs. Two MDO test problems that have complex coupling between disciplines are used to benchmark the performance of each sampling strategy. The results show that these types of variable fidelity RSAs can be effectively managed by the trust region model management strategy to drive convergence of MDO problems. It is observed that the efficiency of the optimization algorithm depends on the sampling strategy used. A comparison of the DOE approaches with those obtained using a optimization based sampling strategy (i.e. concurrent subspace optimization --- CSSO) shows the DOE methodologies to be competitive with the CSSO based sampling methodology in some cases. However, the CSSO based sampling strategy was found to be, in general, more efficient in driving the optimization.
108 citations
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TL;DR: Self-nucleation (SN) as discussed by the authors is a special nucleation process triggered by self-seeds or selfnuclei that are generated in a given polymeric material by specific thermal protocols or by inducing chain orientation in the molten or partially molten state.
Abstract: Self-nucleation (SN) is a special nucleation process triggered by self-seeds or self-nuclei that are generated in a given polymeric material by specific thermal protocols or by inducing chain orientation in the molten or partially molten state. SN increases the nucleation density of polymers by several orders of magnitude, producing significant modifications to their morphology and overall crystallization kinetics. In fact, SN can be used as a tool for investigating the overall isothermal crystallization kinetics of slow-crystallizing materials by accelerating the primary nucleation stage in a previous SN step. Additionally, SN can facilitate the formation of one particular crystalline phase in polymorphic materials. The SN behavior of a given polymer is influenced by its molecular weight, molecular topology, and chemical structure, among other intrinsic and extrinsic characteristics. This review paper focuses on the applications of DSC-based SN techniques to study the nucleation, crystallization, and morphology of different types of polymers, blends, copolymers, and nanocomposites.
107 citations
Authors
Showing all 5925 results
Name | H-index | Papers | Citations |
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Franco Nori | 114 | 1117 | 63808 |
Ignacio Rodriguez-Iturbe | 96 | 334 | 32283 |
Ian W. Hamley | 78 | 469 | 25800 |
Francisco Zaera | 73 | 432 | 19907 |
Thomas G. Habetler | 73 | 395 | 20725 |
Douglas L. Jones | 70 | 512 | 21596 |
I. Taboada | 66 | 346 | 13528 |
Enrique Herrero | 64 | 242 | 11653 |
Rudi Studer | 60 | 268 | 19876 |
Alejandro J. Müller | 58 | 420 | 12410 |
David Padua | 58 | 243 | 11155 |
Rudolf Jaffé | 58 | 182 | 10268 |
Luis Balicas | 57 | 328 | 14114 |
Volker Abetz | 55 | 386 | 11583 |
Ananias A. Escalante | 51 | 160 | 8866 |