Monte Carlo analysis of ridged waveguides with transformation media

A computational model is presented for Monte Carlo simulation of waveguides with ridges, by combining the principles of transformation electromagnetics and the finite methods (such as finite element or finite difference methods). The principle idea is to place a transformation medium around the ridge structure, so that a single and easy‐to‐generate mesh can be used for each realization of the Monte Carlo simulation. Hence, this approach leads to less computational resources. The technique is validated by means of various finite element simulations in the context of 3D waveguides of uniform cross‐section. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2013.     

A Neurogenetic approach for the resource-constrained project scheduling problem

A variety of metaheuristic approaches have emerged in recent years for solving the resource-constrained project scheduling problem (RCPSP), a well-known NP-hard problem in scheduling. In this paper, we propose a Neurogenetic approach which is a hybrid of genetic algorithms (GA) and neural-network (NN) approaches. In this hybrid approach the search process relies on GA iterations for global search and on NN iterations for local search. The GA and NN search iterations are interleaved in a manner that allows NN to pick the best solution thus far from the GA pool and perform an intensification search in the solution's local neighborhood. Similarly, good solutions obtained by NN search are included in the GA population for further search using the GA iterations. Although both GA and NN approaches, independently give good solutions, we found that the hybrid approach gives better solutions than either approach independently for the same number of shared iterations. We demonstrate the effectiveness of this approach empirically on the standard benchmark problems of size J30, J60, J90 and J120 from PSPLIB.     

Effect of a chemical synthesis‐based pharmaceutical wastewater on performance,acetoclastic methanogenic activity and microbial population in an upflow anaerobic filter

The performance of an upflow anaerobic filter (UAF) treating a chemical synthesis‐based pharmaceutical wastewater was evaluated under various operating conditions. During start‐up, the UAF was initially fed by glucose till an organic loading rate (OLR) of approximately 7.5 kg COD m^?3 day^?1 with a hydraulic retention time of 2.3 days. A soluble COD removal efficiency of 98% was achieved before the addition of the wastewater. Initially, the filter inertia was acclimatized to the wastewater by sequential feeding of 10% (w/v), 30% (w/v) and 70% (w/v) of the pre‐aerated wastewater mixed with glucose followed by a 100% (w/v) pre‐aerated wastewater. During the operation, the COD removal efficiency and methane yield decreased to 75% and 0.30 m³ CH₄ kg^?1 COD_removed respectively. As the UAF became accustomed to the pre‐aerated wastewater, raw wastewater was fed in increasing ratios of 20% (w/v), 60% (w/v) and 80% (w/v) with the pre‐aerated wastewater as the remaining part. During this stage of the operation, a COD removal efficiency in a range of 77–86% was achieved and the methane yield decreased to 0.24 m³ CH₄ kg^?1 COD_removed. Finally, 100% (w/v) raw wastewater was fed and a COD removal efficiency of 65% was achieved with a methane yield of 0.20 m³ CH₄ kg^?1 COD_removed. At the end of the operation, acetoclastic methanogenic activity was only measured in the bottom section of the UAF, this showed a 90% reduction in comparison with activity of inoculation sludge. Microscopic examinations revealed that rod‐shaped methanogens remained as the dominant species whereas Methanosarcina‐like species and filaments were present only in insignificant numbers along the UAF. © 2002 Society of Chemical Industry     

Evaluating the nursing academicians in Turkey in the scope of Web of Science: scientometrics of original articles

Scientometrics - Scientometrics, bibliometrics, webometrics, and informetrics are specific research fields that cover statistical analyses of a particular research field which summarize the...     

Phase Engineering of 2D Tin Sulfides

Tin sulfides can exist in a variety of phases and polytypes due to the different oxidation states of Sn. A subset of these phases and polytypes take the form of layered 2D structures that give rise to a wide host of electronic and optical properties. Hence, achieving control over the phase, polytype, and thickness of tin sulfides is necessary to utilize this wide range of properties exhibited by the compound. This study reports on phase‐selective growth of both hexagonal tin (IV) sulfide SnS₂ and orthorhombic tin (II) sulfide SnS crystals with diameters of over tens of microns on SiO₂ substrates through atmospheric pressure vapor‐phase method in a conventional horizontal quartz tube furnace with SnO₂ and S powders as the source materials. Detailed characterization of each phase of tin sulfide crystals is performed using various microscopy and spectroscopy methods, and the results are corroborated by ab initio density functional theory calculations.     

Structuring ship design project approval mechanism towards installation of operator-system interfaces via fuzzy axiomatic design principles

Managing the verification of primary design projects for ship machinery systems is one of the crucial stages in ship building processes. In particular, the design of operator-system interfaces such as remote controls, displays, alarms, workstations, and labels requires a high level of technical expertise and systematic control. This paper focuses on structuring a ship design project approval mechanism (SDPAM) based on fuzzy axiomatic design (FAD) methodology which is concerned with the system design of relevant interfaces on an engine room control console. Design characteristics such as accessibility and operational requirements are treated as “hard” constraints being encountered in this complex problem. Hence, the proposed methodology requires performance assessment using fuzzy values. This study provides original contributions to the existing approval procedures of classification societies, which are non-governmental construction and classification organizations in the shipping industry. Furthermore, the study proposes a new approach to handle uncertainty and vagueness by an axiomatic design extension to ship project execution problems.     

Cultural competence as an ethical requirement: Introducing a new educational model.

Demographic data show a trend toward increasing racial and ethnic diversity among students in public schools, but the teaching population is projected to remain largely White and female. Without proper training, teachers will be ill equipped to meet the educational needs of these diverse students and run the risk of unwittingly perpetuating prevalent stereotypes and discriminatory practices about certain racial and ethnic groups. This preliminary study offers a theoretically driven model for training, the Racial and Ethical Sensitivity Training KIT (REST-KIT), which is designed to (a) increase preservice teachers' ability to recognize ethical dilemmas related to intolerance in schools and (b) provide preservice teachers with techniques and skills for handling these dilemmas. The REST-KIT is unique in that it ties cultural competence to ethical principles based on professional codes of ethics accepted by school professions and emphasizes that cultural competence is a professional requirement, not a personal choice. Pre- and posttests were given to ascertain the program's effectiveness. Both a self-report and a behavior-based measure indicated that participants showed more cultural competence after completing the workshop. Implications and directions for future research are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An integrated fuzzy QFD model proposal on routing of shipping investment decisions in crude oil tanker market

Monitoring the market has crucial roles for executing the shipping investment decisions in maritime transportation industry. The high level of managerial effort requires bringing market tendencies with the up-to-date data over dynamic parameters. This paper extends the Quality Function Deployment (QFD) principles towards shipping investment process via the originally proposed Ship of Quality (SoQ) framework. Furthermore, the Fuzzy Analytic Hierarchy Process (FAHP) and Fuzzy Axiomatic Design (FAD) algorithms are integrated into the SoQ frame in order to involve quantitative outcomes into the shipping investment decisions. The SoQ is performed over a set of periodical data and recent trends of the principal crude oil tanker markets such as Very Large Crude Oil Carriers (VLCCs), Suezmaxes, and Aframaxes in order to ensure the illustrative results. As an effective investment tool, the proposed SoQ model is expected to provide invaluable decision aid for the relevant shipping executives.     

Activation of solgel titanium nanofilm by UV illumination for NOM removal.

The control of natural organic matter (NOM) in drinking water treatment plants is required in order to control (i) the formation of potentially harmful disinfection byproducts (DBPs), (ii) the regrowth of bacteria and (iii) pipe corrosion in the distribution system. Photocatalysis is a promising advanced oxidation technology due to its ability to mineralise chlorinated byproduct precursors such as humic acids (HAs) to carbon dioxide and water. In this study, the efficiency of HAs and NOM removal in terms of UV absorbance at 254 nm (UV254) was tested by means of a new photocatalytic reactor made of stacked polymethylmethacrylate (PMMA) rings coated by TiO2 nanofilm. Three different sets of rings were coated with TiO2 gel one, two and three times respectively to optimise the coating thickness according to UV254 removal efficiency. The titania sol was immobilised on the substrate by a low temperature procedure and after 8 months the reactors were reactivated by means of UV radiation before the experiments. The photocatalytic removal efficiency of humic acid in terms of UV254 was significantly higher after 1 hour for the reactor employed with high thickness TiO2 nanofilm (around 20%) compared to middle and low thickness reactors (6 and 1.4%, respectively). However, during the same reaction time only 10% of UV254 was removed with high thickness TiO2 nanofilm using raw surface water, probably owing to ionic species naturally occurring in the raw water sample. Finally, the activation of the TiO2 nanofilm may be effectively accomplished by means of UV radiation where calcination cannot be applied (e.g. thermally sensitive substrates).     

The false positive effect of residue of sulphur sources on dithiocarbamate analysis based on CS2 measurement

Turkey plays an important role in the international trade of apricots as it has the largest production rate in the world. Since the sulphurisation process is allowed to be used for different products, the effect of residual sulphur and its compounds (which can be found in products as pesticide residues or additive residues) on the positive detection of carbon disulphide (CS₂) still creates a big challenge in international trade. Therefore, the main objective of the present study was to investigate the effects of residues of sulphur or sulphur compounds on dithiocarbamate analysis methods based on CS₂ measurement. In this study, apricots were chosen since they contain sulphur residues as a result of the sulphurisation process. Sulphur dioxide and dithiocarbamate analyses were conducted on dried apricots prepared with the sulphurisation process (SA) and without the sulphurisation process (NSA); analysis was by two different accredited laboratories. No of pesticide was applied to either SA or NSA samples. Although some of the NSA samples had <LOQ values, approximately 70 ± 32 mg/kg SO₂ and 0.061 ± 0.021 mg/kg dithiocarbamate were detected for NSA samples. On the other hand, for the SA sample group, 927–2915 mg/kg of SO₂ and 0.265–0.825 mg/kg of dithiocarbamate were detected. Furthermore, a strong correlation between residual sulphur and dithiocarbamate values was observed. This study showed that the analysis method based on CS₂ measurement may lead to false positive results for dithiocarbamates when residues of sulphur or sulphur compounds are found in products as pesticide or additive residues. Therefore, residual sulphur compounds as a result of the sulphurisation process (which is not considered during the evaluation of products) must be taken into account during the evaluation of products for dithiocarbamates.