Effect of Nd-Substitution on Thermally Activated Flux Creep in the Bi1.7Pb0.3−x Nd x Sr2Ca3Cu4O12+y Superconductors

The magnetoresistance of Bi_1.7Pb_0.3?x Nd _x Sr₂Ca₃Cu₄O_12+y superconductors with x=0.025, 0.050, 0.075 and 0.10 have been measured for different values of the applied magnetic field. Thermally activated flux creep model has been studied in order to calculate the flux pinning energies. The calculated flux pinning energies decrease with the increasing Nd-content and applied magnetic field.     

Estimation and evaluation of sub-bands on LF and HF base-bands in HRV for Ventricular Tachyarrhythmia patients

Heart Rate Variability (HRV) is an efficient tool for assessment of Sympathovagal Balance (SB) and classification of cardiac disturbances. However, its index may be not enough for classification and evaluation of some disease. This study presents 32 new sub-bands over LF and HF base-bands that are accepted in the literature. Moreover, it determines dominant sub-bands over both base-bands in VTA database. These sub-bands are obtained using Wavelet Packet Transform (WPT) and evaluated using Multilayer Perceptron Neural Networks (MLPNN). Results are compared with obtained results from normal datasets. The domination effects of these sub-bands are assessed according to comparison of each other related to MLPNN training and test accuracy percentages by selecting different width of windows. As a result, obtained results showed that the LF zone including LF₁, LF₂ and LF₃ sub-bands on 0.0390625–0.0859375 Hz frequency range is the most dominant over the LF base-band and, the HF zone including HF1, HF2 and HF3 on 0.1953125–0.28125 Hz frequency range is the most dominant over the HF base-band. In normal datasets, distinctive domination effect has not been determined.     

Effects of sowing and harvesting dates on yield and some quality characteristics of crops in sugar beet/cereal rotation system

BACKGROUND: Cereals are the main crops in rotation following sugar beet harvest. However, a delay in planting winter cereals as a result of late sugar beet harvest is a disadvantage in sugar beet/cereal rotations. In this study, field trials were carried out to investigate the effects of sowing and harvesting dates on the yield and quality of sugar beet (Beta vulgaris L.) and cereals (wheat, Triticum aestivum L., and six‐rowed barley, Hordeum vulgare L.) during two consecutive years. Beet was sown on three dates and harvested on four dates, followed by cereals which were sown on four dates. Root yield and digestion ratio (sugar beet) and grain yield, 1000‐kernel weight, test weight and protein content (wheat and barley) were determined. RESULTS: The highest root yield (52.53 t ha^?1) was obtained from early sown (5 April) and late harvested (1 November) beet, while the highest digestion ratio (17.4%) was obtained from late sown (3 May) and late harvested (1 November) beet. Lower cereal grain yields were obtained from later sowings. The highest grain yields (5.87 and 6.02 t ha^?1) were obtained from earlier sown wheat. Protein content was also affected by sowing date, which appeared to be very important under unstable climatic conditions. CONCLUSION: It is essential to consider the timing of sowing of cereal crops when unstable climatic conditions are present. Hence sowing date recommendations in regular climatic conditions may be misleading for countries dependent on winter rainfall for cereal production. Copyright © 2007 Society of Chemical Industry     

The use of mixture experiments in tolerance allocation problems

The response surface methodology (RSM) approach can be used to determine the optimal component tolerances in an assembly. Frequently, response surface designs such as Box-Behnken design and central composite design are used in tolerance allocation problems. In this article, mixture experiments, which are essentially constructed for designing a blend composition, are proposed instead of response surface designs in order to observe the cost values. Also some advantages and disadvantages of mixture designs are discussed.     

Cost optimization of feed mixes by genetic algorithms

The cost optimization is a key element to determine the least-cost feed mixture according to animals’ nutrient requirements and the effective use of the sources. In this paper, the cost optimization of feeds is performed by genetic algorithm, considering the growing style and type, age, nutritional requirement and feedstuff costs for poultry and different types of animals. The proposed method is compared with linear programming approach to measure its performance. The obtained results show that Genetic algorithms could be applicable to the cost optimization of the feed mixtures. In addition, a software program is developed by using Delphi environment, which provides flexible, extensible and user-friendly framework for tuning the heuristic relevant parameters and improving the solution quality.     

Efficient Nonlinear Absorbing Platinum(II) Acetylide Chromophores in Solid PMMA Matrices

Platinum(II) acetylides were incorporated into poly(methyl methacrylate) (PMMA) glasses to obtain solid‐state nonlinear optical devices. We report on device fabrication, structural, chemical, and mechanical properties, as well as the optical limiting capabilities of the final solids. Two different guest‐host systems are presented: 1) Dye molecules functionalized to be readily dispersed in methyl methacrylate (MMA) and subsequent in situ polymerization of the MMA yielding solid PMMA host matrices. 2) Dye molecules functionalized to copolymerize with MMA forming covalent bonds between the guest and the PMMA host matrix. A range of doped organic solids were prepared, reaching concentrations up to 13 wt% of the guest molecule. Raman spectra of the doped solid devices indicate that the chemical structure of the nonlinear dyes remains intact upon the polymerization of the solid matrix. Luminescence spectra confirm that the basic photophysical properties observed for the same solute molecules in THF are maintained also in the solid state. Optical power limiting (OPL) characterization reveal clamping levels for the dyes nonbonded to the solid host being less than 4 µJ at pulse energies up to 110 µJ at 532 nm (f/5 arrangement and 5 ns pulses), which is comparable to the performance of similar dyes in THF solutions. In contrast, the highly crosslinked solid possesses a higher clamping level (8 µJ) at the same nominal concentration.     

Determination of interfacial energies of solid Sn solution in the In–Bi–Sn ternary alloy

The equilibrated grain boundary groove shapes of solid Sn solution (Sn-40.14 at.% In-16.11 at.% Bi) in equilibrium with the In–Bi–Sn liquid (In-21.23 at.% Bi-19.04 at.% Sn) were observed from the quenched sample at 59 °C. Gibbs–Thomson coefficient, solid–liquid interfacial energy and grain boundary energy of the solid Sn solution have been determined from the observed grain boundary groove shapes. The thermal conductivity of solid phase for In-21.23 at.% Bi-19.04 at.% Sn alloy and the thermal conductivity ratio of liquid phase to solid phase at the melting temperature have also been measured with radial heat flow apparatus and Bridgman type growth apparatus, respectively.