A CAD/CAE-integrated injection mold design system for plastic products

Mold design is a knowledge-intensive process. This paper describes a knowledge-based oriented, parametric, modular and feature-based integrated computer-aided design/computer-aided engineering (CAD/CAE) system for mold design. Development of CAx systems for numerical simulation of plastic injection molding and mold design has opened new possibilities of product analysis during the mold design. The proposed system integrates Pro/ENGINEER system with the specially developed module for the calculation of injection molding parameters, mold design, and selection of mold elements. The system interface uses parametric and CAD/CAE feature-based database to streamline the process of design, editing, and reviewing. Also presented are general structure and part of output results from the proposed CAD/CAE-integrated injection mold design system.     

FISTA Algorithm for Radiography Images Enhancement with Background Blurring Removal

Testing and detecting potential defects in works of art is usually required to cause minimal or no damage; industrial Radiography Testing (RT) is often the method of choice provided the images are of the required high quality and yield high defect detection sensitivity. Various digital image processing methods can be employed to achieve improved image quality and information extraction as required. The level and nature of the noise in the RT images is usually unknown. In addition to the different noises, the image quality is degraded by the blurring effect. In this study, a modified form of the Fast Iterative Shrinkage-Thresholding Algorithm (FISTA) with quadratic regularization strategy was developed and applied to remove the blurring. The output of the application of the method to number RT images of five art objects was evaluated by industrial radiography and antiquities experts. It was confirmed that the applied method was efficient and improved image quality and defect detection.     

On the analysis of fracture mechanisms and mechanical behavior of AA5083-based tri-modal composites reinforced with 5 wt.%B4C and toughened by AA5083 and AA2024 coarse grain phases

In this article, the influence of AA2024 and AA5083 coarse grains on mechanical properties and failure mechanisms of AA5083-5wt. %B₄C tri-modal composite has been discussed. AA2024 and AA5083 powders (<100 µm) were added to mechanically milled AA5083-5 wt.%B₄C powders in 25 and 50 wt.% and the mixtures were consolidated using the hot press and hot extrusion techniques. Results indicated that by adding AA2024 and AA5083 powders as coarse grains, hardness and tensile strength of AA5083-5 wt.%B₄C composite decreased but ductility increased. Moreover, by adding AA2024 powders as coarse grains, fracture mode changed and cracks tended to grow through along AA2024/AA5083-5 wt.%B₄C interface rather than being arrested or deflected. It seemed that dislocation mobility and the interface between coarse grains and ultra-fine grains had the main role in determining the mechanical properties and failure mechanisms in tri-modal AA5083-B₄C composites.     

Workflow re-engineering of design-build projects using a BIM tool

The use of design-build delivery methods and building information modeling (BIM) tools in the construction industry has been growing rapidly in recent years due to the increasing demand for more efficient construction project management. The successful implementation of these?tools by engineering firms on projects, however, is still not being achieved consistently. This paper shares the experiences of the implementation of an in-house BIM tool by a large engineering, procurement, and construction firm that has an extensive reputation for design-build projects. A new workflow was proposed that takes full advantage of the BIM tool to both enhance the construction management performance and to minimize the impact on the firm’s existing workflow. The development of a new workflow was conducted by interviewing key personnel in various departments of the firm and by carefully examining probable impacts of the BIM tool’s introduction into the firm’s business processes.     

Visually perceived eye level: Changes induced by a pitched-from-vertical 2-line visual field.

The physical elevation corresponding to visually perceived eye level (VPEL) changes linearly with the pitch of a visual field. Deviations from true eye level average more than 0.5 times the angle of pitch over a 65° pitch range. A visual field consisting of 2 dim, isolated vertical lines in darkness is more than 4/5 as effective as that of a complexly structured visual field; 2 horizontal lines have a small and inconsistent effect. Differences in influence on VPEL between pitched-from-vertical and horizontal lines were predicted from an analysis that extracted differences in retinal perspective resulting from changes in pitch. The Great Circle Model (GCM), based on a spherical approximation to the erect, stationary eye, predicts the present results and results of 8 other sets of experiments. The model treats the influence of a single line on VPEL as systematically related to the elevation of the intersection between the great circle containing the image of the line and the central vertical retinal meridian; generalized GCM combines visual inputs with inputs from the body-referenced mechanism and maps onto the central nervous system. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of Concentration on Steady-State Viscometric Properties of Short Chain Polymer Solutions Over the Entire Concentration Range

Relationships between viscometric behavior and concentration are observed and evaluated through a series of nonequilibrium molecular dynamics simulations of the behavior of 20-site polymers in solution with explicit solvent across the full concentration range. The zero-shear viscosities, first normal stress coefficients and steady-state shear compliance of the solutions are examined alongside conformational properties including the excluded volume effect. The variation of viscosity with concentration in these solutions is described by the Huggins equation up to relatively high concentrations. At these high concentrations, the effects on conformation of excluded volume interactions decline, while no clear semi-dilute region is identifiable. Although the steady-state shear compliance of the system appears concentration-independent, the dilute and melt behaviors of this system are accurately described by the theories of Zimm and Rouse, respectively.     

Theoretical studies of Rhizomucor miehei lipase activation

Computational methods have been used to study the extensiveconformational change of Rhizomucor miehei lipase upon activation.Hie present study considers the possible activation route, theenergies involved and molecular interactions during the conformationalchange of the lipase in a hydrophobic environment. The conformationalchange was studied by conventional molecular dynamics methodsand with a combined molecular dynamics and mechanics protocol,in which the conformational change was simulated by restrainingCor pseudotorsional angles in small steps between the two crystallographicallyobserved positions of the lid. In the closed conformer of theenzyme the active site is completely buried under a short helicalloop, ‘the lid’. The activation of the lipase consistsof a movement of the lid, which results in an open conformerwith an exposed active she. From the results of the simulationsin the present work we suggest that the lipase in a hydrophobicenvironment is stabilized in the open form by electrostaticinteractions.     

Alkaline earth metal oxides on γ-Al2O3 supported Co catalyst and their application to mercaptan oxidation

γ-Al₂O₃-supported alkaline earth metal oxide samples with different MgO, CaO, SrO and BaO loadings have been prepared by impregnating γ-Al₂O₃ with alkaline earth metal nitrate solutions and then calcining at 773 K and 1,023 K. The resultant samples have been characterized by XRD, EDS coupled with SEM, CO₂-TPD and BET. After preparation of the γ-Al₂O₃-supported alkaline earth metal oxide samples and impregnation with the liquid catalyst LCPs30, supplied by Axens, the catalytic performance of these catalysts was evaluated in the mercaptan oxidation reaction. Results showed that magnesium base oxide is formed at 773 K and base oxides of calcium, barium and strontium are formed at 1,023 K. Catalysts with higher mole ratios have higher conversions and the basicity increases with increasing base oxide loading in the samples. Furthermore, the conversion of mercaptans increases with increasing atomic number of the alkaline earth metal, excluding MgO, which has the highest conversion compared to the other base oxides.