Estimating optimum parameters of tuned mass dampers using harmony search

In this paper, the optimum parameters of tuned mass dampers (TMD) are proposed under seismic excitations. Harmony search (HS), a metaheurestic optimization method, which has been successfully applied for several engineering problems, is revised for tuning passive mass dampers. A Matlab program is developed for numerical optimization and time domain simulation. Optimization criteria are the peak values of first storey displacement and acceleration transfer function. In order to find best results, all properties of TMD are searched. For a fast and general optimization, a harmonic loading is utilized for numerical iterations. Also, final TMD parameters are checked under earthquake excitations. This new approach is compared with several other documented methods. Comparisons show that the new approach is more effective than other documented methods and more feasible due to smaller TMD parameters.     

Some structural properties of CdO:F films produced by ultrasonic spray pyrolysis method

The fluorine doped cadmium oxide (CdO:F) samples have been deposited at 250 °C by ultrasonic spray pyrolysis method. Cadmiumacetat-dihydrat and ammonium fluoride have been taken as a source of cadmium and fluorine-dopant respectively. The thickness of the CdO:F samples was about 1.4 μm. X-ray diffraction pattern of the CdO:F samples has revealed that the samples are polycrystalline with cubic sodium chloride structure. There are shifts of the d values (interplanar spacing) for CdO:F samples with respect to standard CdO film. The lattice parameters for cubic structure have been calculated using the Bragg equation. The texture coefficients calculated for various planes at different fluorine concentrations indicate that the samples have exhibited (111) and (200) preferential orientations.     

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.     

陋室铭

“斯是陋室,唯吾德馨”,在中国传统文化中,有关家居文化的追求大抵就是如此了。在今天,“陋室”已逐渐淡出人们的生活,而“德馨”始终是人们的理想。该住宅的主人深受儒家文化的熏陶,对传统的家庭和生活有着深刻的认知。他希望日常生活就浸润在这种文化底蕴中,要求简单扼要。基     

Sensitivity to signal quantization of 43 Gb/s and 107 Gb/s optical 16-QAM OFDM transmission with coherent detection

The sensitivity of optical orthogonal-frequency division multiplexing (OFDM) transmission to the finite resolutions of the digital-to-analog (DAC) and analog-to-digital converters (ADC) has been analyzed using numerical simulations. We show that for back-to-back configuration the requirements regarding the number of quantization bits for the DACs are similar to the ones of the ADCs. After transmission over metro and long-haul distances a higher resolution of the DAC/ADC is required compared to back-to-back configuration. We show that after transmission it is sufficient to enhance either the ADC resolution or the DAC resolution by 1 bit.     

Fundamental limits on time delay estimation in dispersed spectrum cognitive radio systems

In this paper, fundamental limits on time delay estimation are studied for cognitive radio systems, which facilitate opportunistic use of spectral resources. First, a generic Cramer-Rao lower bound (CRLB) expression is obtained in the case of unknown channel coefficients and carrier-frequency offsets (CFOs) for cognitive radio systems with dispersed spectrum utilization. Then, various modulation schemes are considered, and the effects of unknown channel coefficients and CFOs on the accuracy of time delay estimation are quantified. Finally, numerical studies are performed in order to verify the theoretical analysis.     

Catalytic behavior of ruthenium in soybean oil hydrogenation

Soybean oil was hydrogenated with a carbon‐supported ruthenium catalyst (Ru/C) at 165 °C, 2 bar H₂ and 500 rpm stirring speed. Reaction rates, trans isomer formation, selectivity ratios and melting behaviors of the samples were monitored. No catalytic activity was found for the application of 10 ppm of the catalyst, and significant catalytic activity appeared at >50 ppm of active catalyst. The catalyst concentration had an effect on the reaction rate of hydrogenation, but the weight‐normalized reaction rate constant (k_c) was almost independent of the catalyst concentration at lower iodine values. Ru/C generated considerable amounts of trans fatty acids (TFA), including high amounts of trans 18:2, and also stearic acid, due to its very non‐selective nature. The selectivity ratios were found to be low and varied between 1.12 and 4.32 during the reactions. On the other hand, because of the low selectivity, higher slip melting points and solid fat contents at high temperatures were obtained than those for nickel and palladium catalysts. Another different characteristic of this catalyst was the formation (max 1.67%) of conjugated linoleic acid (CLA) during hydrogenation. Besides, CLA formation in the early stages of the reactions did not change very much with the lower iodine values.     

Adsorption of 4-chlorophenol from aqueous solutions by xad-4 resin: isotherm, kinetic, and thermodynamic analysis

Removal of 4-chlorophenol (4-CP) from synthetic aqueous solutions through adsorption on Amberlite XAD-4 resin, a non-ionic macroreticular resins, under batch equilibrium experimental conditions at 298, 308 and 318K was investigated. It is necessary to propose a suitable model to a better understanding on the mechanism of 4-CP adsorption. For this purpose, Langmiur, Freundlich, Toth, and Redlich-Peterson (RP) isotherm models were compared. The two and three parameters in the adopted adsorption isotherm models were determined by the help of MATLAB package program. It was determined that best fitted adsorption isotherm models were obtained to be in the order: Redlich-Peterson>Langmuir>Toth>Freundlich isotherms. The pseudo-second-order kinetic model provided the best correlation to the experimental results. Results of the intra-particle diffusion model show that the pore diffusion is not the only rate limiting step. The lower correlation of the data to the Bangham's equation also represents that the diffusion of the adsorbate into pores of the sorbent is not the only rate-controlling step. The thermodynamic constants of adsorption phenomena; DeltaG degrees, DeltaH degrees, and DeltaS degrees were found as -4.17 (at 298K) kJ/mol, -42.01 kJ/mol, and -0.127 kJ/(mol K), respectively. The results showed that adsorption of 4-CP on Amberlite XAD-4, a nonionic polymeric resin was exothermic and spontaneous.     

Neural Models for the Resonant Frequency of Electrically Thin and Thick Circular Microstrip Antennas and the Characteristic Parameters of Asymmetric Coplanar Waveguides Backed with a Conductor

Neural models for computing the resonant frequency of electrically thin and thick circular microstrip antennas, based on the multilayered perceptrons and the radial basis function networks, are presented. Five learning algorithms, delta-bar-delta, extended delta-bar-delta, quick-propagation, directed random search and genetic algorithms, are used to train the multilayered perceptrons. The radial basis function network is trained according to its learning strategy. The resonant frequency results of neural models are in very good agreement with the experimental results available in the literature. In this paper, the characteristic impedance and the effective permittivity of the asymmetric coplanar waveguide backed with a conductor are also computed by using only one neural model trained by the backpropagation with momentum and the extended delta-bar-delta algorithms. When the performances of neural models are compared with each other, the best results for test are obtained from the multilayered perceptrons trained by the extended delta-bar-delta algorithm.     

不同非热加工技术对百香果果浆杀菌效果及品质变化的比较

为评价不同非热杀菌方式对果蔬原料杀菌效果及品质的影响,该研究分别采用超高压技术（High Hydrostatic Pressure,HHP）、低温等离子体技术（Cold Plasma,CP）和辐照技术三种方式对百香果鲜榨果浆进行杀菌处理。结果表明,三种非热处理方式对果浆中的微生物（2.15 lg(CFU/g)、2.44 lg(CFU/g)、2.34 lg(CFU/g)）均有一定的抑制和杀灭作用,其中300 MPa及以上压力处理和3 kGy辐照量处理后果浆的菌落数均＜1 lg(CFU/g),这两种方式对百香果果浆均有较好的杀菌效果。为了进一步探究超高压处理对果浆贮藏期的影响,该研究还探讨了超高压处理前后的果浆在-20 ℃的条件下储存9个月内微生物含量的变化,实验得出,500 MPa和600 MPa处理的百香果果浆在-20 ℃下储存9个月后微生物含量仍＜2 lg(CFU/g),符合国家安全规定。在理化性质方面,超高压技术和低温等离子体技术能有效保持果浆的色泽（ΔE＜2）和风味（p＞0.05）,且能抑制果浆POD酶、PPO酶的活性,但辐照处理无法钝化PPO酶。综上所述,超高压技术能有效杀灭百香果果浆中的菌落,并能更好地保持果浆的品质,因此超高压技术在百香果果浆中具有较好的商业应用前景。