Design and development of a data acquisition system for photovoltaic modules characterization

Testing photovoltaic generators performance is complicated. This is due to the influence of a variety of interactive parameters related to the environment such as solar irradiation and temperature in addition to solar cell material (mono-crystalline, poly-crystalline, amorphous and thin films). This paper presents a computer-based instrumentation system for the characterization of the photovoltaic (PV) conversion. It based on a design of a data acquisition system (DAQS) allowing the acquisition and the drawing of the characterization measure of PV modules in real meteorological test conditions.     

Calculation and Updating of Reliability Parameters in Probabilistic Safety Assessment

The internal events of nuclear power plant are complex and include equipment maintenance, equipment damage etc. These events will affect the probability of the current risk level of the system as well as the reliability of the equipment parameter values so such kind of events will serve as an important basis for systematic analysis and calculation. This paper presents a method for reliability parameters calculation and their updating. The method is based on binomial likelihood function and its conjugate beta distribution. For update parameters Bayes’ theorem has been selected. To implement proposed method a computer base program is designed which provide help to estimate reliability parameters.     

Sequential Reaction-Separation in a Microchannel Reactor for Liquid–Liquid Phase Transfer Catalysis

A microchannel reactor with guideline structure was investigated to carry out sequential reaction- separation. The catalytic reaction between benzyl chloride and sodium sulfide was demonstrated. Under parallel multiphase flow conditions, the catalytic reaction proceeded with phase separation could be ensured. The phase separation performance was enhanced by performing surface modification.     

Metallocene polypropylene crystallization kinetic during cooling in rotational molding thermal condition

This article is part of an ambitious project. The aim is to simulate mechanical properties of rotomolded part from microstructure consideration. Main objective here is to consider metallocene polypropylene crystallization kinetic (PP) during cooling stage in rotational molding. Crystallization kinetic of metallocene PP is so rapid that microscopy cannot help to observe nucleation and growth. Crystallization rate can be estimated by a global kinetic. Given that cooling in rotational molding is dynamic with a constant rate, Ozawa law appears more appropriate. Ozawa parameters have been estimated by differential scanning calorimetry. In rotational molding thermal condition, Avrami index identifies a complex nucleation intermediate between spontaneous and sporadic. Ozawa rate constant is 68 times higher than this obtained for Ziegler–Natta PP. By coupling transformation rate from Ozawa model and a thermal model developed earlier, the difference between theory and experimental is less than 1%. To optimize rotational molding, study has been completed by sensitivity to adjustable parameters. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Asphaltene aggregation onset during high-salinity waterflooding of reservoirs (a molecular dynamic study)

Abstract

The primary objective of this study is to establish an understanding of the role of high-salinity brine on the intensity of asphaltene aggregation onset during waterflooding of petroleum reservoirs. We already have shown that asphaltenes have a high tendency to form aggregates during waterflooding process when pure- and low salinity-water are injected into reservoirs. To fulfill the present objective, molecular dynamic simulations are performed on asphaltenic-oil/aqueous systems at 550 K-200?bar. The oil phase consists of asphaltenes (10?wt.%) and ortho-xylene, in which asphaltene molecules are completely soluble. Our simulations results reveal that the “salt-in effect” of high-salinity brine (25 wt.% NaCl) on seven different model asphaltenic oils causes a significant reduction of the onset of asphaltene aggregation as compared with pure-water. Such “salt-in effect” is primarily due to a considerable reduction of water miscibility in the oil phase at high pressure and temperature.     

Fermentation of date palm juice by curdlan gum production from Rhizobium radiobacter ATCC 6466™: Purification, rheological and physico-chemical characterization

The present study was undertaken to investigate the possibility of using date palm juice byproducts for curdlan production by Rhizobium radiobacter ATCC 6466™ in batch experiments. A number of operational parameters, namely pH value, temperature range, inoculum ratio, agitation speed, carbon concentration, nitrogen source, and fermentation time, were investigated in terms of their optimal values for as well as individual and synergistic effects on curdlan production. The findings indicated that the strain exhibited a high ability to use the natural substrate under investigation. A curdlan production yield of 22.83 g/l was obtained in 500-ml agitated flasks (50 ml) when the strain was cultivated in the optimal medium (pH, 7; ammonium sulphate concentration, 2 g/l; date glucose juice concentration, 120 g/l) operating at 30 °C with an inoculum ratio of 5 ml/100 ml, an agitation speed of 180 rpm, and a fermentation period of 51 h. The purified date byproducts-curdlan (DBP-curdlan) had a molecular weight of 180 kDa, a linear structure composed exclusively of β-(1,3)-glucosidic linkages, a melting temperature (T_m) and glass transition temperature (T_g) of 1.24 and −3.55 °C, respectively. The average measured heights of its molecules were noted to fluctuate between 14.1 ± 0.07 and 211.73 ± 0.6 μm.     

Application of evolutionary global optimization techniques in the design of RC water tanks

This paper presents evolutionary-based optimization procedures for designing conical reinforced concrete water tanks. The material cost of the tank that includes concrete, reinforcement, and formwork required for walls and floor was chosen as the objective function in the nonlinear optimization problem formulation. The wall thicknesses (at the bottom and at the top), base thickness, depth of water tank, and wall inclination were considered as design variables.Three advanced optimization techniques to solve the nonlinear constrained structural optimization problems were investigated. These methods are: (1) Shuffled Complex Evolution (SCE), (2) Simulated Annealing (SA) and Genetic Algorithm (GA). Several tests were performed to illustrate the robustness of these techniques and results were encouraging for SCE Method. The SCE method proved to be superior to the SA and GA methods in obtaining the best discovered solutions. The paper concludes that the robust search capability of SCE algorithm technique is well suited for solving the structural problem in hand.     

Dielectric analysis of chlorinated polyvinyl chloride stabilized with di‐n‐octyltin maleate

Dielectric relaxation of chlorinated polyvinyl chloride stabilized with di‐n‐octyltin maleate has been studied in the frequency range 1 kHz–1 MHz at various temperatures between 300 and 450 K. A clear dielectric relaxation band (α‐type) associated with dipolar polarization has been observed in the studied range. The stabilizer molecules increase the segmental mobility of the polymer, and specific interaction occurs between both the C? Cl and C?O polar groups. The temperature dependence of the relaxation process was analyzed by combining the critical free volume expression by Cohen and Turnbull with the Williams‐Landel‐Ferry (WLF) model of the thermal expansion of free and occupied volumes. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

The effect of visco-anaesthetic medicament on tactile gag reflex control

Visco-anaesthetic medication has been used for controlling the gagging sensation in 35 dental patients during intra-oral radiography and impression making. The drug was satisfactory in 29 patients and failed to control the gagging reflex in 6 patients. A direct relation between loss of oral sensation and control of gag reflex has been established.