Evaluation of design requirements using fuzzy outranking methods

To increase customer satisfaction, quality function deployment is used to translate customer needs into technical design requirements (DRs). Determination of DRs for product development is very important because these requirements are the vital keys to successful products. The methods used to evaluate DRs in the literature can be categorized into multicriteria evaluation methods such as scoring methods, the analytic hierarchy method, analytic network process, and so forth. There are few papers using fuzzy multi‐attribute outranking methods to evaluate DRs. This article aims to compare the results of three different fuzzy outranking methods to evaluate the DRs in the PVC windows industry. A sensitivity analysis is also made by using the software, FOuR. © 2007 Wiley Periodicals, Inc. Int J Int Syst 22: 1229–1250, 2007.     

Failure Analysis of Two-Dimensional Carbon-Epoxy Composite Plate Pinned Joint

The aim of this study is to investigate failure strength and failure mode of a mechanically fastened carbon-epoxy composite plate of arbitrary orientation. The failure load and the failure mode are analyzed numerically and experimentally. The numerical method includes two steps. First, the stress distribution in the plate is calculated by the use of finite-element method. Second, the failure load and the failure mode are predicted by means of Tsai-Hill and fiber tensile-compressive failure criteria. A computer program was developed which can be used to calculate the failure load, the failure mode, and the propagation of failure. The distance-to-diameter, E/D , and width-to-diameter, W/D , ratios in the plate are changed from 1 to 5 and 2 to 5, respectively. It is found that full bearing strength is developed when E/D and W/D ratios are equal to or greater than 4.     

New organic semiconductor materials: electrical conductivity,thermal properties and application of voltage‐controlled negative resistance device of poly[(2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid)‐co‐(maleic acid)]

BACKGROUND: Electrical conductivity, photoconductivity, voltage‐controlled negative resistance and thermal properties of copolymers of 2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid and maleic acid were investigated in order to obtain new organic semiconductors. RESULTS: The room temperature conductivity of three different copolymers was found to be in the range 1.28 × 10^?8 ? 1.20 × 10^?7 S cm^?1. The dark‐ and photo‐current‐voltage characteristics indicate that the copolymers exhibit voltage‐controlled differential negative resistance behaviour. The electrical conductivity of the polymers increases by photo‐illumination, suggesting that the polymers exhibit photoconductivity. The width of the exponential tail in the forbidden band gap of the three polymers was determined via the transient photocurrent technique and E₀ values were in the range 34.4–36.49 meV. CONCLUSION: The results suggest that the copolymers could be used as organic semiconductor materials. Copyright © 2007 Society of Chemical Industry     

Effects of the aluminum filler content on moisture diffusion into epoxy adhesives in distilled water and sea water

Epoxies are the most common of high‐performance structural adhesives, especially in automotive and aircraft manufacturing. In a variety of industrial applications, epoxy adhesives are required to have enhanced thermal conductivity. The normal method of changing this property is to add to the epoxy a filler of higher conductivity than the continuous phase. Although the improvement in the thermal properties of adhesives by the addition of metal fillers is obvious, their influence on water sorption characteristics of adhesives is not clear. It was the objective of this study to shed light on these aspects, which are lacking in the literature. The emphasis was placed on determining the moisture sorption behavior of aluminum‐powder‐filled epoxy adhesives under complete immersion in distilled water and sea water. Moisture diffusion tests show that the addition of aluminum filler into epoxy decreases the total amount of water intake at saturation in both fluids. However, there appears to be no significant effect of the aluminum filler content on the moisture diffusivity in epoxy adhesive specimens in either distilled water or seawater. It has also been determined that the adhesives adsorb a larger amount of water upon exposure to distilled water than when exposed to seawater, whereas the moisture diffusion rate in the adhesive immersed in seawater is higher than that in distilled water. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1165–1171, 2005     

Analyses of acoustic emission response of a fault breccia in uniaxial deformation

Interpretation of mechanical tests on block-in-matrix rocks (bimrocks) is difficult and often open to dispute as, with deformation, the interactions between blocks, matrix and pores are complex, reflecting the influence of their different shape, size, strength and stiffness. The acoustic emission (AE) technique can be used to record an ultrasound pulse emitted by a defect within the sample at the moment of its occurrence. Typically several deformations occur, such as crack closure, crack initiation or permanent crack damage, but they may be difficult to visualize with a fault breccia. Consequently, with fault breccia it is advisable to focus on the primary stage of deformation where the acoustic emission response may be traced to properties of the breccia, such as block proportions. The paper shows that the different geometrical properties, particularly the volumetric block proportions, are reflected by stress concentrations which in turn trigger specific AE signatures.     

Surface Characterization of Mild Steel During Atmospheric Corrosion After Being Treated by Sodium Dihydrogen Orthophosphate

Protection of Metals and Physical Chemistry of Surfaces - The objective of this study was to characterize the surfaces of the steel products produced locally during their exposure to the industrial...     

Preparation and thermal properties of polyethylene terephthalate/huntite–hydromagnesite composites

In this report, it was aimed to the improve thermal stability of polyethylene terephthalate (PET) by adding huntite/hydromagnesite minerale. PET/huntite/hydromagnesite composites were prepared by adding various proportions of huntite/hydromagnesite to PET. The chemical structures of the composites were characterized by Fourier transform infrared spectroscopy (FTIR) and X‐ray diffraction (XRD) analysis. Thermal properties of the composites were determined by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Glass‐transition temperatures and char yields increased with the increase of the huntite/hydromagnesite content in the composites. The surface morphologies of the composites were investigated by a scanning electron microscopy. The obtained results proved that the composite system is more thermally stable than the pure PET itself. POLYM. COMPOS., 37:3275–3279, 2016. © 2015 Society of Plastics Engineers     

Preparation and characterization of thermally conductive thermoplastic polyurethane/h‐BN nanocomposites

Polyurethane nanocomposites are versatile engineering polymers with unique properties. In this study, nano hexagonal boron nitride containing thermoplastic polyurethane elastomers were prepared via melt blending and hot‐pressing techniques. The nanocomposites were characterized using Fourier transform infrared, differential scanning calorimetry, thermal gravimetric analysis, tensile tests, and thermal conductivity measurements. The surface morphology of the TPU/h‐BN composites was characterized by scanning electron microscopy. The optical properties of the composites were determined by UV transmittance measurements and as the amount of h‐BN increased, optical transparencies decreased dramatically. Nanocomposites displayed higher E‐modulus values and lower elongation at break values than the pure TPU elastomer. Char yields of TPUs increased with increasing h‐BN percentage. Moreover, thermal conductivity of the composite materials improved with the incorporation of h‐BN. POLYM. COMPOS., 35:530–538, 2014. © 2013 Society of Plastics Engineers