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.     

Synthesis and characterization of γ-Bi2O3 based solid electrolyte doped with Nb2O5

γ-phase bismuth oxide is a well known high oxygen ion conductor and can be used as an electrolyte for intermediate temperature solid oxide fuel cells (IT-SOFCs). This study aims to determine new phases of Bi₂O₃-Nb₂O₅ binary system and the temperature dependence of the electrical transport properties. The reaction products obtained in open air atmosphere were characterized by X-ray powder diffractions (XRD). The unit cell parameters were defined from the indexes of the powder diffraction patterns. The γ-Bi₂O₃ crystal system were obtained by doping 0.01 < mole% Nb₂O₅ < 0.04 at 750 °C for 48 and 96 h. Thermal behaviour and thermal stability of the phases were investigated by thermal analysis techniques. Surface and grain properties of the related phases were determined by SEM analysis. The temperature dependence of the electrical properties of γ-Bi₂O₃ solid solution was measured by four-point probe d.c. conductivity method. In the investigated system, the highest value of conductivity was observed for σ _T = 0.016 ohm^?1 cm^?1 at 650 °C on 4 mole% Nb₂O₅ addition. The electrical conductivity curves of studied materials revealed regular increase with temperature in the form of the Arrhenius type conductivity behaviour.     

Speed control of SR motor by self-tuning fuzzy PI controller with artificial neural network

In this work, the dynamic model, flux-current-rotor position and torque-current-rotor position values of the switched reluctance motor (SRM) are obtained in MATLAB/Simulink. Motor control speed is achieved by self-tuning fuzzy PI (Proportional Integral) controller with artificial neural network tuning (NSTFPI). Performance of NSTFPI controller is compared with performance of fuzzy logic (FL) and fuzzy logic PI (FLPI) controllers in respect of rise time, settling time, overshoot and steady state error.     

Investigation of organic solvent/oil sorption capabilities of phenylene-bridged cross-linked poly(alkoxysilane)s

Phenylene-bridged cross-linked poly(alkoxysilane)s produced by the condensation of 1,4-bis(triethoxysilyl) benzene (BTEB) with different lengths of aliphatic diols in proper stoichiometric ratios were successfully prepared. The synthesized phenylene-bridged poly(alkoxysilane)s were characterized by Fourier transform infrared spectroscopy (FTIR), solid-state ¹³C and ²⁹Si cross polarization magic angle spinning nuclear magnetic resonance (CP-MAS NMR), and thermal gravimetric analysis (TGA). The oil and organic solvent uptake capacity, reusability, absorption and desorption kinetics of cross-linked polymers were examined. The effect of chain length of the linear diol monomers on the polymer-solvent interaction was also investigated. The swelling experiments were conducted in oils such as gasoline, euro diesel and organic solvents such as dichloromethane, tetrahydrofuran, benzene and toluene. All the synthesized polymers have high and fast swelling properties in oils and organic solvents. The reutilize properties of polymer in organic solvents were also investigated.     

Estimating graph distance and centrality on shared nothing architectures

We present a parallel toolkit for pairwise distance computation in massive networks. Computing the exact shortest paths between a large number of vertices is a costly operation, and serial algorithms are not practical for billion‐scale graphs. We first describe an efficient parallel method to solve the single source shortest path problem on commodity hardware with no shared memory. Using it as a building block, we introduce a new parallel algorithm to estimate the shortest paths between arbitrary pairs of vertices. Our method exploits data locality, produces highly accurate results, and allows batch computation of shortest paths with 7% average error in graphs that contain billions of edges. The proposed algorithm is up to two orders of magnitude faster than previously suggested algorithms and does not require large amounts of memory or expensive high‐end servers. We further leverage this method to estimate the closeness and betweenness centrality metrics, which involve systems challenges dealing with indexing, joining, and comparing large datasets efficiently. In one experiment, we mined a real‐world Web graph with 700 million nodes and 12 billion edges to identify the most central vertices and calculated more than 63 billion shortest paths in 6 h on a 20‐node commodity cluster. Copyright © 2014 John Wiley & Sons, Ltd.     

Biofunctionalization of magnetic poly(glycidyl methacrylate) microspheres with protein A: Characterization and cellular interactions

Monodisperse poly(glycidyl methacrylate) (m-PGMA) microspheres which show superparamagnetic behaviour were synthesized by dispersion polymerization. Bioligand protein A was covalently immobilized onto glutaraldehyde activated microspheres (3.12 mg protein A per gram of microspheres). Cell culture studies denoted that 61% of total L929 mouse fibroblasts were bound to the m-PGMA microspheres while 84% of total cells were bounding to the protein A immobilized (m-PGMA-PrA) microspheres. Interactions between m-PGMA-PrA microspheres and L929 cells were stronger than that of m-PGMA microspheres due to the non-specific interactions between protein A and cell surface. The cells interacted with m-PGMA-PrA microspheres keep their round form rather than attaching to the tissue culture polystyrene (TCPS) surface. In conclusion, this study consists a basis for the fractionation of blood lymphocytes bearing IgG antibodies on their surfaces by using protein A immobilized m-PGMA microspheres.     

Interdialytic blood pressure obtained by ambulatory blood pressure measurement and left ventricular structure in hypertensive hemodialysis patients

Unlike in subjects with normal renal function, the relationship between hypertension and cardiovascular morbidity and mortality in dialysis patients is still being debated. In order to clarify this issue, we performed 44-hour ambulatory blood pressure measurements (ABPM) during the interdialytic period in a group of 164 hypertensive patients, the blood pressure (BP) control based on conventional antihypertensive strategy previously, on chronic hemodialysis treatment in the Mediterranean region of Turkey. These results were then compared with their echocardiographic data. This is a cross-sectional analysis. The mean ABPM during 44 hours was close to the manually measured predialysis value, but there was a gradual increase in the ABPM values in the interdialytic period. When divided into a group with mild or no left ventricular hypertrophy (LVH) (45 patients) and severe LVH (119 patients), the latter had significantly higher BP levels in all separate periods, while the difference in predialysis BP was not significant. Patients with severe LVH had larger left atrium and left ventricular diameters, and consumed more antihypertensive drugs. Systolic BP during the night before dialysis showed the strongest relation to LVH, but interdialytic weight gain was also independently related to LVH. Yet, 56% of the patients with systolic BP <135 had severe LVH. There is not only an association between BP and presence of LVH, but it is shown that volume expansion is also an important independent determinant of LVH. This may explain the difficulty in identifying hypertension as a cardiac risk factor in these patients.