Beneficial Effect of Compatibilization on the Aging of Cellulose‐Reinforced Biopolymer Blends

The effect of aging on the thermo‐mechanical properties of new biocomposite materials obtained from renewable resources is studied. Cellulose was used as the reinforcing phase and the matrix was composed of a blend of two biopolymers (PEM and PLLA) in order to have a good compromise between stiffness and flexibility. Two grafting agents were used to compatibilize the filler with the matrix. The ensuing materials were then aged at 35 °C and 80% relative humidity during 45 days. Thermal and dynamic mechanical properties of the blends and composites were measured before and after aging. Important variations of crystallinity were observed and results show that grafting allowed obtaining high‐performance composites even after aging.

     

Magnetic and Photocatalytic Activity of Pure BaFe12O19 and BaFe12O19-TiO2 Hexagonal Ferrite Nanocomposites

Journal of Superconductivity and Novel Magnetism - Hard hexagonal barium ferrite BaFe12O19 (BaM), as well as core–shell structure BaFe12O19-TiO2 composite nanoparticles, was successfully...     

Topology optimization of plane structures using smoothed particle hydrodynamics method

This paper presents an alternative topology optimization method based on an efficient meshless smoothed particle hydrodynamics (SPH) algorithm. To currently calculate the objective compliance, the deficiencies in standard SPH method are eliminated by introducing corrective smoothed particle method and total Lagrangian formulation. The compliance is established relative to a designed density variable at each SPH particle which is updated by optimality criteria method. Topology optimization is realized by minimizing the compliance using a modified solid isotropic material with penalization approach. Some numerical examples of plane elastic structure are carried out and the results demonstrate the suitability and effectiveness of the proposed SPH method in the topology optimization problem. Copyright © 2016 John Wiley & Sons, Ltd.     

Quality and exposure control in semiconductor manufacturing. Part II: Evaluation

The purpose of this article is to test the performance of a heuristic algorithm that computes a quality control plan. The objective of the tests reported in this paper is twofold: (1) to compare the proposed heuristic algorithm (HA) to an optimal allocation (OA) method; and (2) to analyse the behaviour and limitations of the proposed HA on a scale-1 test with a before/after test. The method employed to evaluate this algorithm is based on comparisons: 1. The first test illustrates the method and its sensitivity to internal parameters. It is based on a simplified case study of a product from the semiconductor industry. The product is made up of 1000, 800 and 1200 wafers incorporating three different technologies. The production duration is 1 week, and three tools were involved in this test. The behaviour of the proposed algorithm is checked throughout the evolution of the model parameters: risk exposure limit (R_L ) and measurement capacity (P). The quality control plan for each tool and product are analysed and compared to those from a one stage allocation process (named C ⁰) that does not take into account risk exposure considerations. A comparison is also performed with OA.

2. The second scale-1 test is based on three scenarios of several months of regular semiconductor production. Data were obtained from 23 etching and 12 photolithographical tools. The outputs provided by the HA are used in the sampling scheduler implemented at this plant. The resulting samples are compared against three indicators.

The results of these comparisons show that, for small instances, OA is more relevant than the HA method. The HA provides realistic limits that are suitable for daily operations. Even though the HA may provide far from optimal results, it demonstrates major MAR improvement. In terms of the maximum inhibit limit, the HA achieves better performances than C ⁰, and they are strongly correlated to R_L and to the control capacity. The article concludes that the proposed algorithm can be used to plan controls and to guide their scheduling. It can also improve the insurance design for several levels of acceptance of risk.     

Icosahedrons microstrip antenna network architecture proposal for new USS telecommunication subsystem

The paper presents a new antenna network subsystem architecture developed for application on board wireless communication subsystem. Founded research work results demonstrate the success of mathematical modeling and simulation of the proposed Icosahedrons Microstrip Antenna Network Architecture. Antenna elements are simulated, prototyped and tested. The Icosahedrons Microstrip Antenna Network is developed to meet the visibility requirements during inter small USS satellite radio communications.     

Generalization of the polycrystalline β-model: Finite element assessment and application to softening material behavior

On the basis of the polycrystalline model of Cailletaud and Pilvin [G. Cailletaud, P. Pilvin, Rev. Eur. EF 3 (1994) 515–541], a generalization of the β-scale transition rule from the macroscopic level to the grain level is developed in this paper. The new proposed model is split into several sub-models. It is shown that the classical Pilvin–Cailletaud model describes correctly the overall mechanical behavior of softening materials. However, the local mechanical behavior at the grain level is not well simulated. A polycrystalline aggregate model is then generated and computed by the finite element technique to select the most accurate sub-model in predicting both the overall stress–strain response and the local stress and strain distributions. The material parameters of each sub-model are evaluated using the results of the finite element computations at two levels: (i) the macroscopic level, using the volume average over all Gauss points and (ii) the phase scale, using the volume average over the Gauss points of the elements having the same orientation. The most accurate model is compared with experiments using available monotonic tensile data for Ti–6Al–4V. The selected model appears also to be capable of correctly evaluating the stress–strain behavior at the grain level and reducing the deviation of phase strains with regards to the mean strain.     

A design for testability approach for nano-CMOS analogue integrated circuits

Dependability requirements must be considered from the beginning when designing safety-critical systems. Therefore, testing should even be considered earlier, intertwined with the design process. The process of designing for better testability is called design for testability (DfT). This article presents two designs for testability and fault diagnosis techniques using a new design analogue checker circuit in order to improve the testability and the diagnosability of nano-CMOS (complementary metal oxide semiconductor) analogue circuits used in safety-critical applications based on the system-on-chip (SoC) approach design. The testing techniques presented in this work can be done during and after the system fabrication. The checker is implemented in full-custom 65 nm Complementary metal–oxide–semiconductor (CMOS) technology with low supply voltage and small-size capabilities. SPICE simulations of the post-layout extracted CMOS checker, which include all parasitic, are used to validate the technique and demonstrate the acceptable electrical behaviour of the checker.     

Analysis of thin composite structures using an efficient hex-shell finite element

In this paper a general methodology for the modeling of material composite multilayered shell structures is proposed using a Hex-shell finite element modeling. The first part of the paper is devoted to the general FE formulation of the present composite 8-node Hex-shell element called SCH8, based only on displacement degrees of freedom. A particular attention is given to alleviate shear, trapezoidal and thickness locking, without resorting to the classical plane-stress assumption. The anisotropic material behavior of layered shells is modeled using a fully three dimensional elastic orthotropic material law in each layer, including the thickness stress component. Applications to laminate thick shell structures are studied to validate the methodology, and good results have been obtained in comparison with ABAQUS© commercial code.     

Impact of urban upgrading on perceptions of safety in informal settlements: Case study of Bouakal,Batna

This paper explores how modifications of urban space in informal settlements influence residents′ quality of life and perceptions of safety. This is a case study of Bouakal, the oldest informal district in Batna, a middle city in Algeria. This paper examines the effects of urban improvement practices in Bouakal by exploring two questions: In what ways did interventions in this informal settlement affect the quality of life for the residents? How do these effects correlate with changes in the perception of safety in this area? The survey involved 141 residents from Bouakal, and local residents were selected to collect the levels of perceived safety. This paper concludes that urban upgrading has improved the quality of life and has a positive effect on the perception of safety in the settlement.