Selecting the suitable material handling equipment in the presence of vagueness

Selection of the suitable material handling equipment (MHE) is a very difficult task for the manufacturing companies because of the considerable capital investment required. There are many tangible and intangible factors for choosing the suitable MHE. Multiple criteria decision making (MCDM) has been found to be a useful approach to analyze these conflicting factors. The evaluation of MHE alternatives within the frame of various subjective criteria and the weights of the criteria are usually expressed in linguistic terms. This makes fuzzy logic a more natural approach to this kind of problems. This paper proposes a combined MCDM methodology for evaluation and selection of MHE types for a company in the steel construction industry in Istanbul, Turkey. Fuzzy analytic network process (FANP) is utilized for assigning weights of the criteria for MHE selection and fuzzy technique for order preference by similarity to ideal solution (TOPSIS) is used to determine the most proper system alternative using the criteria weights attained by FANP. The selection is based on the compatibility between MHE and production characteristics. Objective is to select the most efficient MHE considering also the cost efficiency. The study was followed by the sensitivity analyses of the results.     

Care transitions in the outpatient surgery preoperative process: facilitators and obstacles to information flow and their consequences

Patient care transitions have been shown to be critical points at which failure as well as recovery from potential failure may occur. The purpose of this research was to identify transitions in patient care and the flow of associated information at different steps in the outpatient surgery preoperative care process and, in turn, attempt to identify breakdowns in the information flow process and their ramifications. A study of one organization’s preoperative process for outpatient surgery was conducted, employing four means of data collection to gather information on preoperative work processes: employee shadowing, patient shadowing, clinic observation, and dictated feedback. Various facilitators and obstacles in information flow were found to be present in the preoperative care process. Obstacles often resulted in negative consequences for healthcare providers and patients. Helping care providers understand how their actions affect the various elements of the preoperative process, through improved awareness, may be one way to improve information flow problems within the outpatient surgery process.     

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Ohne Zusammenfassung VDI     

Development of a multipurpose tile body: Phase and microstructural development

In this study, an attempt was made in order to develop a multipurpose tile body using a single formulation. In order to achieve this, several body recipes were prepared using mainly local raw materials with clearly defined physical and chemical properties at different sieve residues and single fast fired under industrial conditions in the first part of the study. In the second part, the most suitable formulations with the corresponding sieve residues were determined and further fired at different peak temperatures under laboratory conditions in order to establish their vitrification ranges and optimum firing temperatures. The tested peak firing temperatures were varied at 20 °C intervals from 1120 to 1200 °C for multipurpose wall tile body and from 1140 to 1220 °C for multipurpose floor tile body. The physical and thermal properties of the fired bodies such as water absorption, linear firing shrinkage, bulk density and linear thermal expansion coefficient were measured. The vitrification behaviour of the multipurpose bodies was also evaluated using a double-beam optical non-contact dilatometer. Furthermore, the fired bodies were subjected to colour measurements. Particular consideration was given to the phase and microstructural evolution of the developed tile bodies. X-ray diffraction (XRD) was used to analyse the phases formed before and after firing. Scanning electron microscopy (SEM) in combination with energy dispersive X-ray spectroscopy (EDS) was further employed in order to observe the microstructural and microchemical characteristics of the fired bodies with respect to peak firing temperature. The preliminary experimental results showed that it was possible to obtain a multipurpose body with the properties in accordance with ISO-EN 10545.     

Fully Automated Three-Dimensional Column-Switching SPE–FIA–HPLC System for the Characterization of Lipids by a Single Injection: Part I. Instrumental Design and Chemometric Approach to Assess the Effect of Experimental Settings on the Response of ELSD

This article presents the first application of fully automated three‐dimensional (3D) column‐switching SPE–FIA–HPLC system for the characterization of lipids by a single injection. The whole system was designed and set up by modifying Agilent 1200 Series HPLC system in our laboratory. By using this system, a complete separation profile of the oil samples was achieved in a very short time period by using single injections. This approach was applied on vegetable oils which contains a large number of relatively high‐class lipid components, such as TG, FFA, sterols, tocopherols, DG, ester and MG. In this part of the study, we focused on the optimization of evaporative light scattering detector (ELSD) by using an experimental design and RSM. Three experimental parameters were chosen as an independent variables which are the flow rate of mobile phase, nebulization temperature and evaporation temperature. A multivariate five level experimental design was used to establish a quadratic model as a functional relationship between the response values and independent variables. The optimal values of parameters were found to be a flow rate of 1.25 mL min^?1, nebulization temperature of 80 °C, and evaporation temperature of 40 °C. Regression analysis with an R² values indicated as a satisfactory correlation between the experimental and predicted values. ANOVA test results were also illustrate that the models can be successfully used to predict the optimum parameters of ELSD. Thus, the proposed system is suitable for a large number of applications including research and development of new quality control and characterization methods for vegetable oils.     

Computational insights into charge transfer across functionalized semiconductor surfaces

Abstract

Photoelectrochemical water-splitting is a promising carbon-free fuel production method for producing H₂ and O₂ gas from liquid water. These cells are typically composed of at least one semiconductor photoelectrode which is prone to degradation and/or oxidation. Various surface modifications are known for stabilizing semiconductor photoelectrodes, yet stabilization techniques are often accompanied by a decrease in photoelectrode performance. However, the impact of surface modification on charge transport and its consequence on performance is still lacking, creating a roadblock for further improvements. In this review, we discuss how density functional theory and finite-element device simulations are reliable tools for providing insight into charge transport across modified photoelectrodes.     

Microstructural Characterization of Reactively Sintered Mullites

Mullite ceramics have been produced by reaction sintering of powders prepared using pseudoboehmite–colloidal silica and aluminum sulfate–colloidal silica mixtures. The microstructural development of these mullites was studied by a number of transmission electron microscopy based techniques including diffuse dark field, Fresnel fringe defocus imaging, and high-resolution transmission electron microscopy. This characterization procedure showed that mullite ceramics free from glassy phases at triple junctions and grain boundaries could be produced from both mixtures using suitable sintering temperatures and alumina/silica ratios. The wetting of grain boundaries by glass, occurring in the mullite ceramics from either incomplete reaction between alumina and silica components or release of silica from the mullite structure with increasing temperature, was found to depend on the prior thermal history of the ceramics.     

Mechanical characterization of highly porous β-Si3N4 ceramics fabricated via partial sintering & starch addition

In this study, porous β-Si₃N₄ ceramics containing limited amount of Sm₂O₃ and CaO as sintering aids were produced by addition of potato starch (10 and 20 vol.%) and partial sintering. Two different Si₃N₄ powders, α- and β-, were used as starting materials. Scanning electron microscopy investigations revealed that development of elongated β-Si₃N₄ grains were much more pronounced when α-Si₃N₄ starting powder was used. Even though porosity values of the compositions prepared by using α-Si₃N₄ (～57.0–58.4%) is significantly higher than the samples produced by β-Si₃N₄ (42.6%), no significant change was observed for the bending strength, fracture toughness and Weibull modulus. This indicates that microstructural features have a significant contribution to the mechanical properties of the porous materials in terms of bending strength and fracture toughness.