Boundary homogenization for a quasi-linear elliptic problem

We describe the asymptotic behaviour of the solution of a quasi-linear elliptic problem posed in a cylinder and with homogeneous Dirichlet boundary conditions imposed on narrow helicoidal strips ε-periodically distributed on the lateral boundary of this cylinder when the parameter ε goes to 0. We use epi-convergence arguments in order to establish the limit behaviour. We also compute the rate of convergence of the solution of the original problem to that of the limit one.     

Liquid crystal-based optical space switches fordwdm networks

This paper addresses the issue of using conventional liquid crystal materials as reconfigurable holographic or diffractive phase elements within optical space switches and the resulting constraints in their choice and use in a telecommunication environment. We discuss the advantage of this technology for implementing holographic-based approaches with respect to other techniques. As an illustration we give two examples which illustrate two generic architectures and complementary use of liquid crystal to implement them. Finally, we give some trends on implementations of high channel capacity space switches based on this technology.     

Optimisation des performances de modules multipuces Modélisation par réseaux de neurones

Widely used in microwave multichip module design, passive device models are subject to intensive researches. This paper introduces the concept of automate generation of neural models for passives and interconnects. Accurate and fast, these models efficiently integrate electromagnetic effects present at microwave frequencies. By optimizing the circuit performance, the proposed approach can automatically predict not only the final geometrical structure of the different passive components and their respective interconnects but also, for the fist time, their optimum location in the circuit. Applications using passive models implemented in circuit simulators are presented.     

Distance monotonicity and a new characterization of Hamming graphs

Hamming graphs are simply Cartesian products of complete graphs. Several characterizations of these graphs involve the notion of intervals in a graph and related topics. The notion of interval distance monotonicity has already been used in order to obtain a characterization of hypercubes. Here, we revisit this notion and use it to obtain a new characterization of Hamming graphs by performing a combination of the hypercube characterization and the interval hypercube characterization.     

Design of the injection beamline for the Californium Rare Isotope Breeder Upgrade electron beam ion source charge breeder

The design of the ion injection line connecting the electron beam ion source (EBIS) charge breeder and the Californium Rare Isotope Breeder Upgrade radio frequency quadrupole cooler-buncher at the Argonne Tandem Linear Accelerator System was investigated with particle tracking simulations. The injection line was configured to accommodate several differential pumping sections, individual optical components were optimized to minimize emittance growth, and the ion beam parameters were matched with the EBIS electron beam acceptance to minimize losses upon injection.     

A study of the degradation of compatibilized and uncompatibilized peanut shell powder/recycled polypropylene composites due to natural weathering

Compatibilized and uncompatibilized composites containing various loadings of recycled polypropylene (RPP) and peanut shell powder (PSP) were prepared. An amount of 3 parts by weight per hundred parts of resin of poly(ethylene‐co‐acrylic acid) (PEAA) was used as a compatibilizer in the RPP/PSP composites. The effect of PEAA and PSP loading on natural weathering was investigated. Composites without PEAA were used as a control, with the samples being tested before exposure to the environment. The PSP loading was varied from 0 to 40 wt%. The samples were exposed to natural weathering in the northern part of Malaysia for 6 months. The results showed that there was a higher decrease in tensile strength and elongation at break in the uncompatibilized composites compared with the compatibilized composites after exposure. Moreover, the tensile modulus increased for both the uncompatibilized and the compatibilized composites after natural weathering. The weight loss for both the uncompatibilized and the compatibilized RPP/PSP composites with PSP loading of 40 wt% after 6 months exposure was 9.24 and 7.13 wt%, respectively. J. VINYL ADDIT. TECHNOL., 23:290–297, 2017. © 2015 Society of Plastics Engineers     

Tabu search for the redundancy allocation problem of homogenous series–parallel multi-state systems

This paper develops an efficient tabu search (TS) heuristic to solve the redundancy allocation problem for multi-state series–parallel systems. The system has a range of performance levels from perfect functioning to complete failure. Identical redundant elements are included in order to achieve a desirable level of availability. The elements of the system are characterized by their cost, performance and availability. These elements are chosen from a list of products available in the market. System availability is defined as the ability to satisfy consumer demand, which is represented as a piecewise cumulative load curve. A universal generating function technique is applied to evaluate system availability. The proposed TS heuristic determines the minimal cost system configuration under availability constraints. An originality of our approach is that it proceeds by dividing the search space into a set of disjoint subsets, and then by applying TS to each subset. The design problem, solved in this study, has been previously analyzed using genetic algorithms (GAs). Numerical results for the test problems from previous research are reported, and larger test problems are randomly generated. Comparisons show that the proposed TS out-performs GA solutions, in terms of both the solution quality and the execution time.     

Reduction of Listeria monocytogenes and Escherichia coli O157:H7 numbers on vacuum-packaged fresh beef treated with nisin or nisin combined with EDTA.

Nisin or nisin combined with EDTA was used to treat fresh beef. Beef cubes (2.5 by 2.5 by 2.5 cm) that were inoculated with approximately 7 log CFU/ml of Listeria monocytogenes Scott A or Escherichia coli O157:H7 505 B were dipped in the following solutions: (i) H2O, (ii) HCl, (iii) nisin, (iv) EDTA, or (v) nisin combined with EDTA, respectively, for 10 min each, with an exception of one set of control beef samples without treatment. Beef samples were then drip-dried for 15 min, vacuum packaged, and stored at 4 degrees C for up to 30 days. The pH on beef after different treatments was not a key factor in preventing bacterial growth. Treatment with nisin or with nisin combined with EDTA reduced the population of L. monocytogenes by 2.01 and 0.99 log CFU/cm2 as compared to the control, respectively, under the conditions of vacuum package and storage at 4 degrees C for up to 30 days. However, the effect of nisin and nisin combined with EDTA against E. coli O157:H7 505 B was marginal at 1.02 log CFU/cm2 and 0.8 log CFU/cm2 reductions, respectively.     

Neural-based approach for localization of sensors in indoor environment

Location of wireless sensor nodes is an important piece of information for many applications. There are many algorithms present in literature based on Received Signal Strength (RSSI) to estimate the location. However the radio signal propagation is easily influenced by diffraction, reflection and scattering. Therefore algorithms purely based on RSSI may not accurately predict the position of the node. In the present work, an algorithm for estimating the position of mobile nodes is proposed which is based on a combination of Received Signal Strength (RSSI) and Link Quality Indicator (LQI). Artificial Neural Networks are used to establish the relationship between the location of the mobile node and the experimentally obtained values of RSSI and LQI. Two different algorithms namely, Bayesian Regularization and Gradient Descent are used to develop the neural network model. Proposed algorithms improve the localization accuracy and perform better than other state-of-the-art algorithms.     

Evaluation of the Effectiveness of New Compatibilizers Based on EBAGMA‐LDPE and EBAGMA‐PET Masterbatches for LDPE/PET Blends

The present paper is aimed to evaluate the efficiency of two masterbatches, i.e., EBAGMA/LDPE (MB1) and EBAGMA/PET (MB2) with 50/50 w/w composition, prepared by melt mixing and used as new compatibilizers for blends of LDPE/PET. The morphology, the mechanical and the thermal properties of LDPE/PET/MB1 and LDPE/PET/MB2 ternary blends have been investigated. Morphological investigation by SEM of LDPE/PET/MB1 ternary blends showed a finer dispersion of PET in LDPE matrix with a better interfacial adhesion compared to those of both LDPE/PET/MB2 and binary LDPE/PET blends. The results also indicated a substantial improvement in both elongation at break and impact strength, while the Young's modulus decreased. Moreover, the thermal properties showed a decrease of the crystallization phenomena of PET in LDPE/PET/MB1 blend, thus confirming the good dispersion of PET particles into the continuous phase of LDPE matrix, leading to the conclusion that MB1 could be an efficient compatibilizer for LDPE/PET system.