Distribution System Protection with Decentralized Generation Introduced into the System

Cogeneration from renewable energy sources has been universally proposed as a partial alternative to the solution of our nation's energy problems. New technical, safety, and operational problems are introduced when this generation is placed into a distribution grid. Addressed is the problem of distribution system protection with the introduction of cogeneration sources and the changes and modifications which may be required in the application of present-day protection devices. A sample system is considered, and system protection and coordination with and without cogeneration has been calculated through a digital fault and system protection coordination program. The results indicate through the study of several systems that additional coordination and protection considerations will be required when sizable cogeneration sources are introduced to maintain a high degree of reliability and service continuity.     

A hybrid heuristic workflow scheduling algorithm for cloud computing environments

Cloud computing is a relatively new concept in the distributed systems and is widely accepted as a new solution for high performance and distributed computing. Its dynamisms in providing virtual resources for organisations and laboratories and its pay-per-use policy make it very popular. A workflow models a process consisting of a series of steps that shape an application. Workflow scheduling is the method for assigning each workflow task to a processing resource in a way that specific workflow rules are satisfied. Some scheduling algorithms for workflows may assume some quality of service parameter such as cost and deadline. Some efforts have been done on workflow scheduling on cloud computing environments with different service level agreements. But most of them suffer from low speed. Here, we introduce a new hybrid heuristic algorithm based on particle swarm optimisation (PSO) and gravitation search algorithms. The proposed algorithm, in addition to processing cost and transfer cost, takes deadline limitations into account. The proposed workflow scheduling approach can be used by both end-users and utility providers. The CloudSim toolkit is used as a cloud environment simulator and the Amazon EC2 pricing is the reference pricing used. Our experimental result shows about 70% cost reduction, in comparison to non-heuristic implementations, 30% cost reduction in comparison to PSO, 30% cost reduction in comparison to gravitational search algorithm and 50% cost reduction in comparison to hybrid genetic-gravitational algorithm.     

Fast Thermal Generation Rescheduling

A new dynamic programming algorithm for fast rescheduling thermal generation is presented. The savings in computational times are brought about by the introduction of two new techniques: the variable truncation dynamic programming and the limitation of the solution space to be searched. Several examples on a 20 machine system are used to illustrate the application of the algorithm and to show that optimal solutions are obtained at significantly reduced computational times.     

Hybrid Amine-Functionalized Titania/Silica Nanoparticles for Solid-Phase Extraction of Lead,Copper, and Zinc from Food and Water Samples: Kinetics and Equilibrium Studies

In the present study, hybrid amine-functionalized titania/silica nanoparticles were employed as a new and novel adsorbent for solid-phase extraction of Pb²⁺, Cu²⁺, and Zn²⁺ ions prior to their determination using flame atomic absorption spectrometry. Under the best conditions (including adsorbent, 0.4 g; eluent, 5.0 mL nitric acid (HNO₃), 3.0 mol L^?1, 1.0 mL min^?1; and sample, pH 5.0, 3.0 mL min^?1), detection limits, adsorption capacities, and preconcentration factors were 0.12–0.24 μg L^?1, 7.1–20.7 mg g^?1, and 200, respectively. To predict the adsorption isotherms, different isotherm models were studied and the obtained results showed that the Langmuir model is the most suitable one to explain the experimental data. The kinetics of the reaction followed pseudo-second-order kinetic model. Thermodynamic parameters like free energy (ΔG ⁰) and enthalpy (ΔH ⁰) confirmed the spontaneous and exothermic nature of the process. The method was successfully applied for determination of the analytes in different food and water samples.     

Viscosity and rheological behavior of castor–canola mixture

In this work, the effects of shear rate on viscosity of selected pure food grade oils (castor and canola) are investigated. The rheological behavior of castor–canola oil mixture is also studied through modeling the experimental data. The effect of shear rate on the variation of viscosity was clearly observed. Interpretations of the results from rheological models indicate that these food grade oils belong to pseudo‐plastic category. The results also show that among the six used mixing rules, Grunberg–Nissan model seems very well fitted to the experimental data.     

Extraction and Enrichment of Triazole and Triazine Pesticides from Honey Using Air‐Assisted Liquid–Liquid Microextraction

In the present work, an easy, fast, and effective approach is developed for the extraction and enrichment of triazole and triazine pesticides in honey by air‐assisted liquid–liquid microextraction coupled with gas chromatography‐flame ionization detection. Initially, honey is dissolved in an acetonitrile: water mixture and after that a few microliter of a less soluble organic solvent in aqueous phase is added. In order to form a cloudy solution, the extractant mixed with aqueous phase is repeatedly sucked and expelled by a syringe needle into a glass tube. After centrifugation, the sedimented phase (1 mL) is removed with a syringe and injected into de‐ionized water. By this action, the settled phase volume is reduced to 10 μL and the analytes are concentrated, too. Under optimum extraction conditions, limits of detection and quantitation for the studied pesticides are in the ranges of 2 to 5 and 6 to 17 ng/g, respectively. Extraction recoveries and enrichment factors are from 61% to 95% and 61 to 95, respectively.     

The Effects of Asphaltene Deposition on Unconsolidated Porous Media Properties during Miscible Natural Gas Flooding

Abstract

The deposition of asphaltenes in porous media is a complex phenomenon, which needs to be investigated under dynamic flowing conditions. Here, the likelihood of asphaltene deposition problems during dynamic displacement of dead oil by natural gas in unconsolidated porous media is experimentally inspected. Dynamic experiments showed a considerable increase in asphaltene deposition in the unconsolidated matrix during natural gas injection. The results show that increase in asphaltene deposition leads to pore plugging, porosity, and absolute permeability reduction of the porous media. Irreducible water measurements show that natural gas-induced asphaltenes change the sandstone wettability to oil-wet.     

Performance optimization of pharmaceutical supply chain by a unique resilience engineering and fuzzy mathematical framework

Pharmaceutical supply chains (PSCs) are responsible for guaranteeing that the right people receive the right medication at the right time and in the right conditions. These responsibilities make PSC very complex and subsequently increase their vulnerability and disturbance probability. Resilience engineering (RE) can enable supply chain managers to cope with disruptions and to help them maintain their efficient performance. This study proposes a unique RE framework for performance optimization of the pharmaceutical sector in a veterinary organization. A standard questionnaire was used to collect the required data. Next, data envelopment analysis (DEA) and fuzzy data envelopment analysis (FDEA) approaches were employed to formulate the problem. Sensitivity analysis was performed based on the most appropriate model of DEA and FDEA. The results showed that redundancy was the most effective factor in enhancing efficiency in PSCs in the veterinary organization. This is one of the first studies that investigate the influence of resilience indicators on PSC through DEA/FDEA and statistical methods.     

Combinatorial optimization of resilience engineering and organizational factors in a gas refinery by a unique mathematical programming approach

This study is an attempt to evaluate the mutual impacts of resilience engineering (RE) and managerial and organizational factors in a large gas refinery. RE is a paradigm for safety management that focuses on how to help people cope with complexity under pressure to achieve success. The data obtained from questionnaire are analyzed by statistical methods and data envelopment analysis (DEA) approach. The results of Cronbach's alpha test show that the data are reliable. The results of DEA demonstrate that learning and flexibility among all RE factors have the greatest impact on managerial and organizational factors. In addition, the organizational factors have a greater influence on RE in comparison with managerial factors. Spearman's test was used to verify the results of this study. This is the first study that identifies the most important factors of integrated managerial and organizational factors and RE through a unique mathematical programming approach in a gas refinery.