Effect of simultaneous double doping in Ba and Ti sites on dielectric and ferroelectric properties of sol–gel synthesized nano-BaTiO<Subscript>3</Subscript>

Lead free (Ba_(1−3x)Nd_(2x))(Ti_(1−y)Zr_y)O₃ (x = 0, 0.025, y = 0, 0.025, 0.05) ceramics were prepared successfully using sol–gel method. The effect of Nd, Zr content on dielectric and polarisation properties of BaTiO₃ were studied using dielectric and hysteresis measurements. SEM analysis proved that the particle size of compounds as prepared were in the order of 30–60 nm. The ferroelectric phase transition from tetragonal to cubic phase was observed around 130 °C for pure BaTiO₃. With the addition of Nd (2.5 mol%) and increasing content of Zr (2.5 and 5 mol%), it was observed that transition temperature (T_c) shifts to lower temperatures (70–50 °C), but didn’t show any relaxor behaviour. Dielectric measurements showed an increase in the values at room temperature in all the doped samples. The synthesized ceramics exhibited typical P–E hysteresis loops at room temperature accompanied by saturation polarisation (P_s) and remanent polarisation (P_r). Behaviour of polarisation phenomena in these compounds showed interesting results with increasing temperature.     

EMG pattern classification using SOFMs for hand signal recognition

 We propose a method of pattern classification of electromyographic (EMG) signals using a set of self- organizing feature maps (SOFMs). The proposed method is simple to apply in that the EMG signals are directly input to the SOFMs without preprocessing. Experimental results are presented that show the effectiveness of the SOFM based classifier for the recognition of the hand signal version of the Korean alphabet from EMG signal patterns.     

Quantitative stochastic simulation of telecommunication networks in DESC+ +

DESC+ + (Discrete Event Simulation package using C+ +) has been developed as an object-oriented tool for quantitative simulation studies of communication protocols and architectures of telecommunication networks. The main issue of such performance studies is to secure proper statistical accuracy of the final simulation results. In DESC+ + this problem has been solved by automating analysis of simulation output data, aimed at stopping simulation when the estimates reach the required level of precision. The package consists of various object classes. While some of them are responsible for on-line output data analysis, others allow simulation programs of telecommunication networks to be easily developed by re-using existing (sub)models. We discuss main design and implementational issues of DESC+ +, and illustrate them by an example.     

Molecular analysis of the rfaD gene, for heptose synthesis, and the rfaF gene, for heptose transfer, in lipopolysaccharide synthesis in Salmonella typhimurium

We report the analysis of three open reading frames of Salmonella typhimurium LT2 which we identified as rfaF, the structural gene for ADP-heptose:LPS heptosyltransferase II; rfaD, the structural gene for ADP-L-glycero-D-manno-heptose-6-epimerase; and part of kbl, the structural gene for 2-amino-3-ketobutyrate CoA ligase. A plasmid carrying rfaF complements an rfaF mutant of S. typhimurium; rfaD and kbl are homologous to and in the same location as the equivalent genes in Escherichia coli K-12. The RfaF (heptosyl transferase II) protein shares regions of amino acid homology with RfaC (heptosyltransferase I), RfaQ (postulated to be heptosyltransferase III), and KdtA (ketodeoxyoctonate transferase), suggesting that these regions function in heptose binding. E. coli contains a block of DNA of about 1,200 bp between kbl and rfaD which is missing from S. typhimurium. This DNA includes yibB, which is an open reading frame of unknown function, and two promoters upstream of rfaD (P3, a heat-shock promoter, and P2). Both S. typhimurium and E. coli rfaD genes share a normal consensus promoter (P1). We postulate that the yibB segment is an insertion into the line leading to E. coli from the common ancestor of the two genera, though it could be a deletion from the line leading to S. typhimurium. The G+C content of the rfaLKZYJI genes of both S. typhimurium LT2 and E. coli K-12 is about 35%, much lower than the average of enteric bacteria; if this low G+C content is due to lateral transfer from a source of low G+C content, it must have occurred prior to evolutionary divergence of the two genera.     

New powellite type oxides in Ca–R–Nb–Mo–O system (R = Y, La, Nd, Sm or Bi)—Their synthesis, structure and dielectric properties

New complex oxides having powellite (CaMoO₄) type structure in the Ca–R–Nb–Mo–O system (R = Y, La, Nd, Sm or Bi) were prepared employing the method of solid state reaction between the component oxides at high temperature (1000–1100 °C). The new compounds, CaRNbMoO₈ (R = Y, La, Nd, Sm, Bi) are colorless and electrical insulators. The dielectric constants (K at 1 MHz) of these compounds are in the range 14–33 and K shows very little variation in the temperature range 30–100 °C. Their temperature coefficient of dielectric constant (TCK) is negative, which varies from − 21 to − 220 ppm/°C.     

Development of a stochastic optimization for multireservoir scheduling

Seasonal reservoir scheduling for multireservoir hydrothermal power systems is a practical, nonlinear, stochastic problem of high dimension. Extension of an existing deterministic algorithm to handle stochastic aspects is desirable. A linear feedback rule, but with chance constraints on lower limits only, gives some promising results. Exact solution by stochastic dynamic programming is possible only for a one-reservoir model. This result is compared to the deterministic and linear feedback solutions.     

Self-tuning PID controllers for dead time processes

A number of proportional-integral-derivative (PID) based self-tuning controllers exist for the control of difficult processes. A common weakness of these self-tuning PID controllers is their inability to cope with dead-time processes. Here, self-tuning controllers based on a pole-assignment approach, which can overcome fractional dead time, constant and known dead time, plus time-varying dead time, are presented. It is shown using the simulation and experimental results that the controllers work well in handling dead-time processes     

Intelligent System for Adapting to a User’s Characteristics

In this paper, we propose an intelligent system that adapts itself to a user’s characteristics or habits. The proposed intelligent system is composed of two Learning Vector Quantisation (LVQ) networks, commonly used in the fields of pattern recognition and signal processing. From the external condition of the plant, the first LVQ network learns to recognise the pattern of the sensed signal, and then aids the second LVQ to learn the user’s characteristics or habits so as to automatically produce the user’s favoured output. To verify the usefulness of the proposed method, we simulated and experimented with a variable illuminator. Both simulation and experimental results showed that the proposed intelligent system learns to automatically produce the illuminator output that the user most favours for the circumstances.     

Characterization of Date (Deglet Nour) Seed Free and Bound Polyphenols by High‐Performance Liquid Chromatography‐Mass Spectrometry

Date (Pheonix dactylifera L.) seeds are a valuable and abundant by‐product with various potential food applications. Free polyphenols (FPPs) and bound polyphenols (BPPs) of date seeds from Deglet Nour variety grown in Australia were investigated using high‐performance liquid chromatography‐mass spectrometry. The FPP fraction contained the following main phenolic compounds per gram of date seed powder; procyanidin B1 (499.8 ± 7.8 μg), procyanidin B2 (288.6 ± 6.1 μg), catechin (167.6 ± 2.1 μg), epicatechin (39.44 ± 0.39 μg), and protocatechuic acid (1.77 ± 0.22 μg). Additionally, one of the 2 A‐type dimers was confirmed as procyanidin A2 (24.05 ± 0.12 μg/g). A‐type dimers have not been reported before in date seeds. The BPP fraction contained epicatechin (52.59 ± 0.76 μg/g) and procyanidin B2 (294.2 ± 3.7 μg/g), while several peaks exhibiting ESI^? m/z of 153 indicated dihydroxybenzoic acid isomers including protocatechuic acid (2.138 ± 0.025 μg/g). These findings contributed to our knowledge of date seed phytochemicals and understanding of their contribution to the reported bioactivities.