A hybrid evolutionary algorithm for distribution feeder reconfiguration

This paper presents a new method to reduce the distribution system loss by feeder reconfiguration.This new method combines self-adaptive particle swarm optimization(SAPSO) with shuffled frog-leaping algorithm(SFLA) in an attempt to find the global optimal solutions for the distribution feeder reconfiguration(DFR).In PSO algorithm,appropriate adjustment of the parameters is cumbersome and usually requires a lot of time and effort.Thus,a self-adaptive framework is proposed to improve the robustness of PSO.In ...     

Novel nanostructure-based electrochemical sensor for simultaneous determination of dopamine and acetaminophen

A carbon-paste electrode modified with a novel molybdenum (VI) complex and carbon nanotubes have been applied to the electrocatalytic oxidation of dopamine (DA) which reduced the overpotential by about 125 mV with obviously increase the current response. Due to its strong electrocatalytic activity towards DA, the modified carbon-paste electrode can resolve the overlapped voltammetric waves of DA and acetaminophen (AC) into two well-defined voltammetric peaks with peak-to-peak separation in potentials of about 230 mV. This property allows to selective determination of DA in the presence of AC. The transfer coefficient (a) for the electrocatalytic oxidation of DA and diffusion coefficient of this substance under the experimental conditions were also investigated. In phosphate buffer solution of pH 7.0, the oxidation current increased linearly with two concentration intervals of DA, one is 0.1 to 40.0 μM and, the other is 40.0 to 800.0 μM. The detection limit (3σ) obtained by DPV was 76.0 nM. The proposed method was successfully applied to the determination of DA, and AC in some commercial pharmaceutical samples.     

Comparison between conventional and ultrasonic preparation of beef tallow biodiesel

Tallow is biodiesel feedstock that, due to its highly centralized generation in slaughter/processing facilities and historically low prices, may have energetic, environmental, and economic advantages that could be exploited. Transesterification of fatty acids by means of ultrasonic energy has been used for biodiesel production from different vegetable oils. However, application of ultrasonic irradiation for biodiesel production from beef tallow has received little attention. In this work, the transesterification of beef tallow with methanol was performed in the presence of potassium hydroxide as a catalyst using ultrasound irradiation (400 W, 24 kHz). The reaction time, conversion and biodiesel quality were compared with that seen in conventional transesterification. The results indicated that the reaction conversion and biodiesel quality were similar; however, the use of ultrasonic irradiation decreased the reaction time, showing that this method may be a promising alternative to the conventional method.     

ZMVHA-B1, the gene for subunit B of vacuolar H+-ATPase from the eelgrass Zostera marina L. Is able to replace vma2 in a yeast null mutant

A vacuolar H(+)-ATPase (VHA) gene (ZMVHA-B1) was isolated from an eelgrass (Zostera marina) leaf cDNA library and was characterized to be approximately 1.4 kbp in length and to encode the B subunit protein of VHA comprising 488 amino acids. ZMVHA-B1 was highly expressed in all organs of eelgrass; the expression level was highest in the leaves. On transformation of a yeast vma2 null mutant with ZMVHA-B1, yeast cells became able to grow at pH 7.5, accompanied by the vesicular accumulation of LysoSensor green DND-189. Thus, ZMVHA-B1 expressed in yeast cells produced a functional B subunit that was efficiently incorporated into the VHA complex and eventually restored vacuolar morphology and activity. This success expedites the application of heterologous expression in yeast mutant cells to the screening of eelgrass genes involved in salt-resistance mechanisms, which are to be utilized in improving important crops.     

A general solution to the material performance index for bending strength design

This paper presents a general solution to the material performance index for the bending strength design of beams. In general, the performance index for strength design is where σ_f is the material strength, ρ is the material density and q is a function of the direction of scaling. Previous studies have only solved q for three particular cases: proportional scaling of width and height (q = 2/3), constrained height (q = 1) and constrained width (q = 1/2). This paper presents a general solution to the exponent q for any arbitrary direction of scaling. The index is used to produce performance maps that rank relative material performance for particular design cases. The performance index and the performance maps are applied to a design case study.     

Investigation of encapsulation of pancreatic beta cells and curcumin within alginate microcapsules

Cell encapsulation is an ideal approach for the replacement of pancreatic function in Type 1 diabetes. Poor biocompatibility of microcapsules generates an inflammatory response in the implantation site and induces fibrosis infiltration, which causes microencapsulated cell death and graft failure. To prevent inflammation after implantation, composite microcapsules that exhibit anti-inflammatory properties were designed. This study is about encapsulating beta cells and curcumin within 1.5% alginate by the jet-breaking regime of the syringe pump. The microcapsules’ size distribution and rate of the alginate solution were characterized to find uniform particles. Micro-size particles were attained at a rate of 25 mL/min. Uniform spherical microcapsules (200–300 μm) were created in large amounts in a short period. Microcapsule breakage was less than 3% during 7 days, which demonstrated the stability of the encapsulation method. Insulin secretion and cell viability assays were performed 1, 3, and 7 days after microencapsulation by glucose-stimulated insulin secretion (GSIS) and 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assays. No significant differences in the amount of insulin secretion and beta cell viability were observed among free cells, alginate microcapsules, and curcumin-alginate microcapsules during 7 days (p > 0.05). Therefore, the curcumin and alginate membrane did not show any harmful impacts on the function and survival of the beta cells.     

Towards automated HPC scheduler configuration tuning

High performance computing (HPC) systems allow researchers and businesses to harness large amounts of computing power needed for solving complex problems. In such systems a job scheduler prioritizes the execution of jobs belonging to users of the system in a manner that allows the system to satisfy performance objectives for various groups of users while simultaneously making efficient use of available resources. Typically, system administrators have the responsibility of manually configuring or tuning the job scheduler such that the performance objectives of user groups as well as system‐level performance objectives are met. Modern job schedulers used in production systems are quite complex. Through detailed trace‐driven simulations, we show that manually tuning the configuration of production schedulers in an environment characterized by multiple performance objectives is very challenging and may not be feasible. To alleviate this problem, this paper describes a toolset that can help a system administrator to automatically configure a scheduler such that the performance objectives for various classes of users in the system as well as other system‐level performance objectives can be satisfied. A unique aspect of this work that differentiates it from the existing work on scheduler tuning is that it has been implemented to work with a widely used production scheduler. Furthermore, in contrast to the existing work it considers the challenging real‐world problem of delivering different levels of performance to different classes of users. System administrators can exploit the toolset to react quickly to changes in performance objectives and workload conditions. Case studies using synthetic and real HPC workloads demonstrate the effectiveness of the technique. Copyright © 2011 John Wiley & Sons, Ltd.     

Turbulent Magneto-Convection in a Differentially Heated Enclosure

Numerically investigation was carried out for turbulent magnetohydrodynamics natural convection in a square enclosure.The vertical walls are maintained isothermal at different temperatures and the horizontal walls are adiabatic.Non linear goveming equations for the fluid flow and heat transfer are solved by finite volume method.The computations are carded out for Rayleigh number 107,Hartmann numbers from 0 to 800 and Prandtl number 0.01(sodium).It is observed that as the Hartmarm number increases the stratification of the temperature field in the interior reduces,and the thermal boundary layers at the two side walls begin to diminish and the isotherms become almost parallel to the vertical walls which indicates that natural convection heat transfer has been changed to conduction mode.     

Effect of Tank Size and Geometry on the Flow Induced by Circular Bubble Plumes and Water Jets

Ambient flow field and circulation patterns induced by circular bubble plumes and water jets in tanks of different sizes were studied in rectangular and square water tanks. A nonstationary nature of the flow was observed in all experiments and its dominant oscillation frequency was found to directly relate to the tank size. The flow circulation patterns were similar for bubble plumes and water jets, but changed significantly with tank size and geometry. Strong three-dimensional effects were observed in a rectangular tank, resulting in flow entraining in the longer plane and flow detraining in the shorter plane, especially for the bubble plume tests. A relationship was developed to relate the tank size to the patterns of circulation cells. Nearly isotropic turbulent flow conditions were obtained in all experiments, but the effect of tank size and geometry on the magnitude of the turbulent stresses was more pronounced in the bubble plume tests.