Bacterial foraging solution based fuzzy logic decision for optimal capacitor allocation in radial distribution system

This paper proposes a novel methodology for the optimal location and sizing of shunt capacitors in radial distribution systems. This method is based on a fuzzy decision making which using a new evolutionary method. The capacitor placement optimization problem includes: minimizing the cost of peak power, reducing energy loss and improving voltage profile. The installation node is selected by the fuzzy reasoning supported by the fuzzy set theory in a step by step procedure. Also an evolutionary algorithm known as bacteria foraging algorithm (BFA) is utilized in solving the objective multivariable optimization problem and the optimal node for capacitor placement is determined. The proposed approach is applied to 34-bus distribution system as a test study and the results are compared with previous method. The results show that this method provides more economic solution by reducing power losses, energy loss, total required capacitive compensation and show a good improvement in nodes voltage to be in the requested range. Comparison between the proposed method in this paper and similar methods in other research works shows the effectiveness of the proposed method for solving optimum capacitor planning problem.     

A Lexicographic Optimization and Augmented ϵ-constraint Technique for Short-term Environmental/Economic Combined Heat and Power Scheduling

Abstract—In recent years, combined heat and power units have become significant elements in conventional power stations due their numerous merits, including operational cost savings and reduced emissions. In this regard, this article proposes a short-term multi-objective framework for the combined heat and power economic/emission dispatch problem. In addition, to more precisely model the problem, the non-linear forms of fuel cost functions and valve-point loading along with power transmission loss are considered. The objectives of the problem are total cost minimization as well as minimization of pollutant emissions; lexicographic optimization and the augmented epsilon-constraint technique are employed to solve the multi-objective problem. Also, a fuzzy decision making technique has been used to select the most preferred solution among the Pareto solutions. Afterward, a comprehensive comparison is performed between the results obtained from the proposed method and those derived from the non-dominated sorting genetic algorithm II, strength Pareto evolutionary algorithm 2, and multi-objective line-up competition algorithm, verifying the superiority of the presented approach for lower execution time, total cost, and emission. Furthermore, the proposed model is implemented on a large-scale test system while the execution time is rational.     

A proposed real options method for assessing investments

Real options analysis is being increasingly used for assessing investments under uncertainty; however, traditional real options methods have some characteristics that restrict their use, such as modeling the value of the underlying asset using geometric Brownian motion and assuming a fixed cost in exercising the options. In this paper, another real options method is expounded that mitigates some of the difficulties posed by traditional methods. Another important aspect that we analyzed in this paper is considering the fuzzy aspects of real options theory. In this section, we are trying to use fuzzy logic concepts integrated with system dynamics to assessing real options in investment projects and we examine dynamic versions of fuzzy logic systems. System dynamics (SD) is an effective method for studying dynamic conditions and changes in complex systems. In this paper, a new dynamic model of real-world systems is designed based on the concepts of system dynamic and fuzzy logic approach. The method is explained with an example from aviation. The analysis offers obvious proof that the integrated fuzzy–SD model could help investors to decide how they should choose an investment program, that managers can use the same results to restructure the program to improve the financial feasibility of the project, and that both investors and managers can define minimum needs to ensure program success.     

Multifunctional and thermoresponsive unimolecular micelles for tumor-targeted delivery and site-specifically release of anticancer drugs

Considering the fact that tumors have a lower pH value and a higher temperature than a normal tissue, a new type of thermoresponsive and biodegradable micelles, based on the H40-poly(?-caprolactone)-b-poly(N-isopropylacrylamide-co-acrylamide)-fluorescein methyl ester/b′-methoxy poly(ethylene glycol)/poly(ethylene glycol)-folate (i.e., H40-PCL-b-P(NIPAAm-co-AAm)-FL/b′-MPEG/PEG-FA (HPPNAP-FA)) with imaging and targeting moieties on the periphery were developed for the tumor-targeted delivery and temperature-induced site-specifically release of hydrophobic anticancer drugs. The amphiphilic HPPNAP-FA copolymer was able to self-assemble into unimolecular micelles in aqueous solution with an average diameter of 65 nm. The lower critical solution temperature (LCST) of micelles was around 39.5 °C. The anticancer drug, paclitaxel (PTX), was encapsulated into the multifunctional micelles. In vitro release studies demonstrated that the drug-loaded delivery system is relatively stable at physiologic conditions but susceptible to mild acidic environments and temperatures above LCST which would trigger the release of encapsulated drugs. Both flow cytometry and fluorescent microscopy showed that the cellular uptake of the PTX-loaded HPPNAP-FA micelles is higher than that of the PTX-loaded HPPNAP because of the folate receptor mediated endocytosis. The efficacy of this thermoresponsive drug delivery system was also evaluated at temperatures above the LCST (40 °C); the results demonstrated that the cellular uptake and the cytotoxicity of PTX-loaded micelles increase prominently. These results indicate that these multifunctional and thermoresponsive unimolecular micelles are promising biomaterials to improve the delivery efficiency and cancer specificity of hydrophobic chemotherapeutic drugs.     

Crystal structure and orientation of uniaxially and biaxially oriented PLA and PP nanoclay composite films

Cast films of poly(lactic acid) (PLA) and polypropylene (PP) with 2.5 and 5 wt % organo modified nanoclay were prepared and then uniaxially and biaxially hot drawn at T = 90 and 155°C, respectively, using a biaxial stretcher. The orientation of PLA and PP crystal unit cells, alignment of clay platelets, as well as the extent of intercalation and exfoliation were studied using wide angle X‐ray diffraction (WAXD). The measurement of d‐spacing of the 001 plane (normal to platelets plane) of the clay tactoids indicated the intercalation of the silicate layers for the PLA nanocomposite films, whereas the PP nanofilled films showed only dispersion of the nanoparticles (i.e., neither intercalation nor exfoliation were observed). The intercalation level of the clay platelets in PLA was almost identical for the uniaxially and biaxially drawn films. Our finding showed that the crystallite unit cell alignments are appreciably dependent on uniaxial and biaxial stretching. Moreover, the incorporation of clay to some extent influenced the orientation of the crystal unit cell axes (a, b, and c) of the oriented films. The silicate layers revealed a much higher orientation into the flow direction in the uniaxially stretched films compared to the biaxially drawn samples. In addition, the orientation of the 001 plane of nanoclays was significantly greater in the PLA compared to the PP nanoclay composite films probably due to a better intercalation and stress transfer in the former. Morphological pictograms illustrating the effects of uniaxial and biaxial stretching on the clay orientation are proposed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

A study of the electrophoretic deposition of bioactive glass-chitosan composite coating

Bioactive glass is coated on implant's surface to improve corrosion resistance and osseointegration, when placed in the body. Bioactive glass particles were synthesized through a sol-gel process and deposited along with chitosan to form a composite coating on a stainless steel substrate using electrophoretic deposition technique. Stable suspensions of chitosan-bioactive glass were prepared using bioactive glass particles (<1 μm) and 0.5 g/l chitosan solution. The influence of ethanol-water ratio on deposition yield was investigated. For all process conditions, best results were achieved with suspension of 30 vol% water in ethanol-water containing 2 g/l bioactive glass. FTIR studies showed that chitosan was absorbed on ceramic particle surface via hydroxyl and amid bonds. In order to evaluate the coating, its structure and electrochemical properties were studied. It was concluded that increasing the process voltage led to an increase in particle size and porosity, but induced cracks in the coating. In the presence of the polymer-bioactive glass coating, current density in artificial saliva was decreased by 52% and corrosion potential shifted toward more noble values.     

Deformation–wear transition map of DLC coating under cyclic impact loading

A new deformation–wear transition map of hydrogen-free amorphous carbon coating (commonly known as Diamond-Like Carbon (DLC) coating) on tungsten high speed steel (SKH2) substrate under cyclic impact loading has been proposed to clarify the interactions of the operating parameters, deformation and wear. The study was carried out using an impact tester, under lubricated conditions over a wide range of impact cycles, and applied normal loads. SKH2 discs were coated with thin DLC films using a Physical Vapor Deposition (PVD) method. Tungsten (W) was used as an interlayer material. The DLC coated disc was impacted repeatedly by a chromium molybdenum steel (SCM420) pin. All impact tests were conducted at room temperature. It has been suggested that the deformation–wear transition map is an easy way to illustrate the impact wear mechanisms of DLC coating, as shown by its transition zones. Initially, the DLC coating only follows the plastic deformation of the substrate until several impact cycles. Then, a suppression of plastic deformation of the substrate is taking place due to the decreasing contact pressure with impact cycles to the yield point. Wear of the DLC coating becomes dominant when the critical limit of maximum normal impact load and impact cycles is exceeded. From experimental observations, some degradation of the DLC coating occurs within the wear zone.     

Circuit implementation of a fully programmable and continuously slope tunable triangular/trapezoidal membership function generator

In this article, a fully programmable membership function generator (MFG) is proposed. This MFG is capable of generating triangular, trapezoidal as well as both S-shaped and Z-shaped membership functions simultaneously. Utilizing a differential pair as an analog switch leads to relax the design of fuzzy systems control part. This MFG has the ability of adapting itself with various fuzzy controllers which produce different control voltage ranges. Unlike the available reported literatures, this MFG uses a new analog programmable current mirror (APCM) instead of digitally programmable current mirrors to adjust the slopes of membership functions. Extensive time domain simulations have been carried out using Hspice by level 49 parameters (BSIM3v3) in standard CMOS technology to validate the effective performance of the proposed MFG.     

Application of Glazing for Bread Quality Improvement

Glazing is a surface coating method for enhancement of the quality factors of bakery products. This study was intended to investigate the effect of different bakery glazing groups such as natural, polyols, sugars, and hydrocolloids on Barbari flat bread. Some quality attributes of bread such as moisture content, water activity, specific volume and width/height ratio (0 day) and hardness, crumb, and crust moisture (0–12 days) were evaluated. Results showed that vegetable oil treated samples had the lowest water activity and moisture content. Also, xanthan treatment provided the greatest effect on the specific volume of fresh bread, which enhanced it from 3.94 to 5 cm³/g. Vegetable oil, glycerol, dextrose, liquid glucose, and guar treatments had more significant effect on width/height ratio in comparison to nontreated (unglazed) bread. Evaluation of crumb hardness and moisture during 12 days storage implicated water, egg yolk, starch, and propylene glycol treatments were able to diminish the bread staling and these treated samples had the lowest crumb hardness. Crumb moisture of Barbari bread was affected mostly by water and starch treatments at day 12. Finally, our finding approved that using of glazing as a novel method is an effective technique for improvement of overall quality of flat bread and its application is suggested for large-scale production of other bakery products.