Effect of eggshell and silk fibroin on styrene–ethylene/butylene–styrene as bio-filler

SEBS (poly(styrene-b-ethylene/butylene-b-styrene)) biodegradable composites reinforced with various eggshell contents and silk fibroin are prepared by melt processing technique followed by different characterization techniques. Compare with SEBS/eggshell composites, the SEBS/eggshell/silk composites exhibit the reduction in particle size and increase interface interaction within the matrix. Thermal stability also increases in quantity.     

Chemically modified fly ash for fabricating super-strong biodegradable poly(vinyl alcohol) composite films

Composite films of poly(vinyl alcohol) (PVA) and chemically modified fly ash (MFA) by sodium hydroxide were prepared by aqueous cast method with 5, 10, 15, 20 and 25 wt% MFA treated with 1 wt% cross-linking agent (glutaraldehyde, GLA). The tensile strengths of the composite films were found to increase proportionally with MFA and the maximum strength attained was 414% higher in the case of 20 wt% MFA than that in neat PVA film. The percentage of strain at break exponentially decreased with addition of MFA. The modulus of the composites was determined to increase proportionally up to a maximum 685% at 20 wt% MFA compared to that of neat PVA film. Interfacial networking between the MFA and PVA was evident from scanning electron microscopy (SEM) images of tensile-fractured surfaces, which was not observed for the unmodified fly ash (FA) system. Atomic force microscopy (AFM) analysis showed that the mean square surface roughness of the composite films of PVA–MFA was 53% smoother than the films with FA.     

Combining convergence and diversity in evolutionary multiobjective optimization

Over the past few years, the research on evolutionary algorithms has demonstrated their niche in solving multiobjective optimization problems, where the goal is to find a number of Pareto-optimal solutions in a single simulation run. Many studies have depicted different ways evolutionary algorithms can progress towards the Pareto-optimal set with a widely spread distribution of solutions. However, none of the multiobjective evolutionary algorithms (MOEAs) has a proof of convergence to the true Pareto-optimal solutions with a wide diversity among the solutions. In this paper, we discuss why a number of earlier MOEAs do not have such properties. Based on the concept of epsilon-dominance, new archiving strategies are proposed that overcome this fundamental problem and provably lead to MOEAs that have both the desired convergence and distribution properties. A number of modifications to the baseline algorithm are also suggested. The concept of epsilon-dominance introduced in this paper is practical and should make the proposed algorithms useful to researchers and practitioners alike.     

Built-in self-test of MEMS accelerometers

A built-in self-test technique that is applicable to symmetric microsystems is described. A combination of existing layout features and additional circuitry is used to make measurements from symmetrically located points. In addition to the normal sense output, self-test outputs are used to detect the presence of layout asymmetry that are caused by local, hard-to-detect defects. Simulation results for an accelerometer reveal that our self-test approach is able to distinguish misbehavior resulting from local defects and global manufacturing process variations. A mathematical model is developed to analyze the efficacy of the differential built-in self-test method in characterization of a wide range of local manufacturing variations affecting different regions of a device and/or wafer. Model predictions are validated by simulation. Specifically, it has been shown that by using a suitable modulation scheme, sensitivity to etch variation along a particular direction is improved by nearly 30%.     

A poly-framed LDD sub-half-micrometer CMOS technology

A novel LDD spacer technology that uses disposable silicon nitride spacers on a sacrificial polysilicon frame has been developed for a sub-half-micrometer CMOS technology. An improvement in short-channel behavior is achieved due to a reduction in lateral LDD n^- and p^- diffusion, and the effect of substrate bias on the drain junction leakage caused by sidewall spacer formation is eliminated. The DC hot-carrier lifetime for the 0.3-μm-channel-length poly-framed LDD NMOS devices, defined as the time associated with a 10% shift in peak transconductance, is in excess of 10 years for a power supply voltage of 3.3 V     

Investigation of pyroelectric characteristics of 0.8 Pb (Zn1/3Nb2/3)O3 - 0.1 Pb TiO3 - 0.1 BaTiO3 ceramics with special reference to uncooled infrared detection

The pyroelectric characteristics for 0.8 Pb(Zn_1/3Nb_2/3)O₃ - 0.1 PbTiO₃ - 0.1 BaTiO₃ ceramics were investigated to determine the usefulness of this material as an uncooled infrared detector. Two successive phase transitions, changing the crystal symmetry from rhombohedral to tetragonal, and then to cubic on a heating process, were observed in the material. The results of measurements were compared with those of PLZT (8/40/60) and the Ca-Modified PbTiO₃, which are currently the favored materials for uncooled arrays. The results indicate that 0.8 PZN - 0.1 PT - 0.1 BT is a promising material for both transverse mode and pyroelectric CCD arrays.     

The superionic Agl-Ag2O-V2O5 system: Electrical conductivity studies on glass and polycrystalline forms

Superionic conducting glasses in the Agl-Ag₂O-V₂O₅ system were prepared by heating the appropriate amounts of raw materials at 723 K and quenching in liquid nitrogen. The polycrystalline materials were prepared by slowly cooling the melt to room temperature. X-ray diffraction was used for material characterization. The electrical conductivity of the pulverized samples, pressed together with an electrode mixture of silver and electrolyte (1:2 by weight) under 5000 kg cm^–2 pressure to form pellets 10 mm in diameter and 2 to 3 mm in thickness, was measured in the temperature range 300 to 365 K at 1 kHz. The ionic conductivities of the glasses were always higher than those of their polycrystalline counterparts, while their activation energies were also slightly higher. Conductivity measurements on annealed glassy samples indicated that the conductivity decreases with the time of annealing, and reaches a constant value which is nearly the same as that of the polycrystalline sample. Electronic conductivities of both types of sample were obtained by using Wagner's polarization cell technique, which showed that the electronic conductivity for both types was five orders of magnitude less than the total conductivity. Typical galvanic cells having the configuration Ag,electrolyte/electrolyte/C,electrolyte,I₂ were constructed and the silver ion transport number was calculated by the e.m.f. method.     

Self-adaptive genetic algorithms with simulated binary crossover

Self-adaptation is an essential feature of natural evolution. However, in the context of function optimization, self-adaptation features of evolutionary search algorithms have been explored mainly with evolution strategy (ES) and evolutionary programming (EP). In this paper, we demonstrate the self-adaptive feature of real-parameter genetic algorithms (GAs) using a simulated binary crossover (SBX) operator and without any mutation operator. The connection between the working of self-adaptive ESs and real-parameter GAs with the SBX operator is also discussed. Thereafter, the self-adaptive behavior of real-parameter GAs is demonstrated on a number of test problems commonly used in the ES literature. The remarkable similarity in the working principle of real-parameter GAs and self-adaptive ESs shown in this study suggests the need for emphasizing further studies on self-adaptive GAs.     

Bridge capacitor bank design and operation

The concept of a bridge capacitor bank installation was presented in a previous paper (see N.G. Andrei et. al., IEEE Trans. Power Systems, vol.8, no.4, p.1463-70, 1993). This paper discusses design and operation aspects related to the installation of a bridge capacitor bank in a substation. The 138/69 kV bridge capacitor bank installation presented by Andrei et. al. is analyzed. An automatic switching control relay scheme for the same test installation is also discussed. The control scheme takes into account the dual effect a bridge capacitor installation has upon the electrical power system: it generates reactive power on the station 138 kV bus and transfers reactive power from the 69 kV to the 138 kV bus. An unbalance protection scheme preventing the cascading type failure of the capacitor units in the 138/69 kV bridge capacitor bank is also presented. An unbalance protection scheme for high voltage, large MVAr size bridge capacitor banks is also discussed. Simple analytical formulas with practical value to evaluate the magnitude and frequency of the voltage transients generated by the energization of a bridge capacitor bank are presented. Recorded switching transient magnitudes and frequencies are compared with calculated values