Effects of fluorine doping on the structural properties of the CdO films deposited by ultrasonic spray pyrolysis

The fluorine doped cadmium oxide samples have been deposited at 250 °C by ultrasonic spray pyrolysis method. X-ray diffraction patterns of the CdO:F samples have revealed that the samples are polycrystalline with cubic sodium chloride structure. The texture coefficients calculated for various planes at different fluorine concentrations indicate that the samples have exhibited (1 1 1) and (2 0 0) preferential orientations. The lattice parameters for cubic structure of each diffraction plane have been calculated. The crystallite size of the samples being nearly constant until 4% of fluorine doping showed reasonable decrease above this concentration value. The macro strain and dislocation density vary with fluorine concentrations.     

Magnetic hydrophobic affinity nanobeads for lysozyme separation

N-Methacryloyl-l-phenylalanine (MAPA) containing poly(2-hydroxyethylmethacrylate) based magnetic [mag-poly(HEMA–MAPA)] nanobeads was prepared for lysozyme purification form chicken egg white. MAPA was synthesized by reacting methacryloyl chloride with l-phenylalanine methyl ester and provided hydrophobic functionality to the nanobeads. Size of mag-poly(HEMA–MAPA) nanobeads was 386 nm and obtained by surfactant free emulsion polymerization of HEMA and MAPA having a specific surface area of 580 m²/g. Mag-poly(HEMA–MAPA) nanobeads were characterized by FTIR, AFM, TEM, ESR, and elemental analysis. Lysozyme adsorption experiments were investigated under different conditions in batch system (i.e., medium pH, protein concentration, temperature, salt type). Lysozyme adsorption capacity of mag-poly(HEMA) and mag-poly(HEMA–MAPA) nanobeads from aqueous solutions was estimated as 24 and 517 mg/g, respectively. Lysozyme molecules were desorbed with 50% ethylene glycol solution with 98% recovery. It was observed that mag-poly(HEMA–MAPA) nanobeads can be used without significant decrease in lysozyme adsorption capacity after ten adsorption–desorption cycles. Mag-poly(HEMA–MAPA) nanobeads was used for the purification of lysozyme from chicken egg white. Purity of lysozyme was estimated by SDS-PAGE.     

Adaptive linkage crossover

Problem-specific knowledge is often implemented in search algorithms using heuristics to determine which search paths are to be explored at any given instant. As in other search methods, utilizing this knowledge will more quickly lead a genetic algorithm (GA) towards better results. In many problems, crucial knowledge is not found in individual components, but in the interrelations between those components. For such problems, we develop an interrelation (linkage) based crossover operator that has the advantage of liberating GAs from the constraints imposed by the fixed representations generally chosen for problems. The strength of linkages between components of a chromosomal structure can be explicitly represented in a linkage matrix and used in the reproduction step to generate new individuals. For some problems, such a linkage matrix is known a priori from the nature of the problem. In other cases, the linkage matrix may be learned by successive minor adaptations during the execution of the evolutionary algorithm. This paper demonstrates the success of such an approach for several problems.     

High-performance implementation of in-network traffic pacing for small-buffer networks

Demands on data communication networks continue to drive the need for increasingly faster link speeds. Optical packet switching networks promise to provide data rates that are sufficiently high to satisfy the needs of the future Internet core network. However, a key technological problem with optical packet switching is the very small size of packet buffers that can be implemented in the optical domain. Existing protocols, for example the widely used Transmission Control Protocol (TCP), do not perform well in such small-buffer networks. To address this problem, we have proposed techniques for actively pacing traffic at edge networks to ensure that traffic bursts are reduced or eliminated and thus do not cause packet losses in routers with small buffers. We have also shown that this traffic pacing can improve the performance of conventional networks that use small buffers (e.g., to reduce the cost of buffer memory on routers). A key challenge in this context is to develop systems that can perform such packet pacing efficiently and at high data rates. In this paper, we present the design and prototype of a hardware implementation of our packet pacing technique. We discuss and evaluate design trade-offs and present performance results from an prototype implementation based on a NetFPGA fieldprogrammable gate array system. Our results show that traffic pacing can be implemented with few hardware resources and without reducing system throughput. Therefore, we believe that traffic pacing can be deployed widely to improve the operation of current and future networks.     

Design and analysis of a fault tolerant hybrid mobile scheme

Mobile computing systems provide users with access to information regardless of their geographical location. In these systems, Mobile Support Stations (MSSs) play the role of providing reliable and uninterrupted communication and computing facilities to mobile hosts. The failure of a MSS can cause interruption of services provided by the mobile system. Two basic schemes for tolerating the failure of MSSs exist in the literature. The first scheme is based on the principle of checkpointing used in distributed systems. The second scheme is based on state information replication of mobile hosts in a number of secondary support stations. Depending on the replication scheme used, the second approach is further classified as a pessimistic or an optimistic technique. In this paper, we propose a hybrid scheme which combines the pessimistic and the optimistic replication schemes. In the proposed scheme, an attempt is made to strike a balance between the long delay caused by the pessimistic and the high memory requirements of the optimistic schemes. In order to find the best ratio between the number of pessimistic to the number of optimistic secondary stations in the proposed scheme, we used fuzzy logic. We also used simulation to compare the performance of the proposed scheme with those of the optimistic and the pessimistic schemes. Simulation results showed that the proposed scheme performs better than either schemes in terms of delay and memory requirements.     

Fractionation effects of polystyrene on acylation reaction and their adhesive and corrosive properties

First, polystyrene (PS) was fractionated using solvent-precipitation methods; then the chemical modification of PS was investigated in the presence of Lewis acid [BF₃·O(C₂H₅)₂] catalyst with some anhydrides such as phthalic anhydride, glutaric anhydride, maleic anhydride, and propionic anhydride. The amount of the polyfunctional groups bonded to polymer structures changed depending on the molecular weight of the polymer, and more functional groups connected to the highest-molecular-weight fraction. The amount of the bonded functional groups was determined with the chemical analysis method. The structures of PS functionalized with anhydrides were confirmed by FTIR, ¹H NMR, and thermogravimetric studies. Their adhesion capability and corrosion resistance against metals have been investigated under various conditions. The results showed that the addition of functional groups to PS increases its adhesion capability and corrosion resistance. This increase is attributed to the quantity of the functional groups bonded to PS.     

Photochemical Degradation of Recycled High-Impact Polystyrene

Photooxidative aging of high-impact polystyrene sheets at 25°C was followed for different intervals of 25, 40, 50, 75, and 80 h. Five different types of samples were used, viz. virgin, and recycled once, twice, three, and four times. The optical properties of exposed samples exhibited changes as a result of discoloration. The transmittance and reflection deceases whereas absorbance increases with increasing recycling of high-impact polystyrene.     

Crystallization behaviour and properties of multicomponent strontium—Containing lithia calcia silicate glasses

The crystallization behaviour of lithia calcia silicate system containing MgO, SrO, and Al₂O₃ has been investigated using DTA, XRD and SEM. The coefficient of thermal expansion and Vicker's microhardness of the obtained products were also evaluated. The main crystalline phases formed after different heat-treatments were lithium metasilicate, wollastonite, diopside, β-spodumene ss, pseudo-wollastonite, Sr₂SiO₄, Sr₂Mg(Si₂O₇) and μ-(Ca,Sr)SiO₃. The wollastonite structure can accept considerable amount of strontium to form wollastonite strontium solid solution, while there is no solid solution of strontium in pseudo-wollastonite.     

Reinforced concrete deep beam shear strength capacity modelling using an integrative bio-inspired algorithm with an artificial intelligence model

The design and sustainability of reinforced concrete deep beam are still the main issues in the sector of structural engineering despite the existence of modern advancements in this area. Proper understanding of shear stress characteristics can assist in providing safer design and prevent failure in deep beams which consequently lead to saving lives and properties. In this investigation, a new intelligent model depending on the hybridization of support vector regression with bio-inspired optimization approach called genetic algorithm (SVR-GA) is employed to predict the shear strength of reinforced concrete (RC) deep beams based on dimensional, mechanical and material parameters properties. The adopted SVR-GA modelling approach is validated against three different well established artificial intelligent (AI) models, including classical SVR, artificial neural network (ANN) and gradient boosted decision trees (GBDTs). The comparison assessments provide a clear impression of the superior capability of the proposed SVR-GA model in the prediction of shear strength capability of simply supported deep beams. The simulated results gained by SVR-GA model are very close to the experimental ones. In quantitative results, the coefficient of determination (R²) during the testing phase (R² = 0.95), whereas the other comparable models generated relatively lower values of R² ranging from 0.884 to 0.941. All in all, the proposed SVR-GA model showed an applicable and robust computer aid technology for modelling RC deep beam shear strength that contributes to the base knowledge of material and structural engineering perspective.