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Design Applications (design + application)
Selected AbstractsExamples of fire engineering design for steel members, using a standard curve versus a new parametric curveFIRE AND MATERIALS, Issue 2-4 2004C. R. Barnett Abstract This paper presents examples of the differences that can occur when a standard time-temperature curve and a parametric time-temperature curve are used to determine temperatures likely to be reached by uninsulated and insulated steel members during a fire. For low and moderate structural fire severity situations, determination of the adequacy of a steel member by comparing the temperature reached in a ,design fire' with the limiting temperature based on the member heat sink characteristics, extent of insulation and utilization factor is becoming increasingly common fire engineering design practice. For this it is important to have an accurate and widely applicable parametric fire model as is practicable. The standard time-temperature curve used in the examples is the ISO 834 curve. The two parametric time-temperature curves used in the paper are the Eurocode parametric curve and a recently developed one termed the ,BFD curve'. The latter has been found to fit the results of a wide range of actual fire tests more closely than do existing parametric curves and is mathematically simpler in form. The shape of the BFD curve and the parameters used to define it bear a strong relationship to both the pyrolysis coefficient (R/Avhv0.5) and the opening factor, F02. The curve also models the development of fire without the need for time shifts. It uses a single and relatively simple equation to generate the temperature of both the growth and decay phases of a fire in a building and only three factors are required to derive the curve. These factors are (i) the maximum gas temperature, (ii) the time at which this maximum temperature occurs, and (iii) a shape constant for the curve. If desired, the shape constant can be different on the growth and the decay sides to model a very wide range of natural fire conditions and test results. This paper presents an overview of the background to the BFD curve. It then illustrates its use in a simple fire engineering design application, where the adequacy of a steel beam is checked using the Eurocode parametric curve and the BFD curve to represent the fire. Copyright © 2004 John Wiley & Sons, Ltd. [source] Development of High Strength Magnesium Based MMC Reinforced with SiC Particles for Satellite Structure ApplicationsMATERIALWISSENSCHAFT UND WERKSTOFFTECHNIK, Issue 4 2003B. Landkof Abstract The appearance of Metal Matrix Composites has opened a new area in structural design. The possibility of tailoring mechanical properties of structural metals reinforced with particles or fibers into specific spacecraft applications is very appealing. This paper deals with such a MMC, which is based on a magnesium alloy matrix and SiC reinforcement. The technology used is a commercial semi-solid die-casting, which promises a cost-effective solution. The results of the first stage of this research are discussed with a focus on the satellite structure design application. The next steps of this investigation are also presented. [source] Reforms Towards Intellectual Property-Based Economic Development in MalaysiaTHE JOURNAL OF WORLD INTELLECTUAL PROPERTY, Issue 4 2009Lim Heng Gee It has been constantly asserted that the intellectual property (IP) system is an effective way to enhance creativity, technological innovations, trade and competitiveness. Others, however, maintain that the IP system may not necessarily be the most effective and appropriate way to fuel the economy. This article investigates the role that IP plays in the economic development of Malaysia from 1986 to 2006. In particular, the article examines the impact of IP-based reforms, which includes not only the IP laws but other IP-related policies with a view to determine how these policies contribute to economic development in Malaysia. For this purpose, the article starts with a brief summary of important IP-related policies. Then the article proceeds with an analysis of trends in IP applications such as patent, trademark and industrial design application. Using data such as numbers of IP filing and grant, this article suggests ways in which the reforms in IP-related policies could have supported growth or could have directly influenced trends in IP application in Malaysia. The article further examines the growth of IP applications in four industrial sectors in Malaysia, i.e. automobiles, information technology, pharmaceuticals, and information and communications technology. [source] Asymmetric one-storey elastic systems with non-linear viscous and viscoelastic dampers: Earthquake responseEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 4 2003Wen-Hsiung Lin Abstract Investigated are earthquake responses of one-way symmetric-plan, one-storey systems with non-linear fluid viscous dampers (FVDs) attached in series to a linear brace (i.e. Chevron or inverted V-shape braces).Thus, the non-linear damper is viscous when the brace is considered rigid or viscoelastic (VE) when the brace is flexible. The energy dissipation capacity of a non-linear FVD is characterized by an amplitude-dependent damping ratio for an energy-equivalent linear FVD, which is determined assuming the damper undergoes harmonic motion. Although this formulation is shown to be advantageous for single-degree-of-freedom (SDF) systems, it is difficult to extend its application to multi-degree-of-freedom (MDF) systems for two reasons: (1) the assumption that dampers undergo harmonic motion in parameterizing the non-linear damper is not valid for its earthquake-induced motion of an MDF system; and (2) ensuring simultaneous convergence of all unknown amplitudes of dampers is difficult in an iterative solution of the non-linear system. To date, these limitations have precluded the parametric study of the dynamics of MDF systems with non-linear viscous or VE dampers. However, they are overcome in this investigation using concepts of modal analysis because the system is weakly non-linear due to supplemental damping. It is found that structural response is only weakly affected by damper non-linearity and is increased by a small amount due to bracing flexibility. Thus, the effectiveness of supplemental damping in reducing structural responses and its dependence on the planwise distribution of non-linear VE dampers were found to be similar to that of linear FVDs documented elsewhere. As expected, non-linear viscous and VE dampers achieve essentially the same reduction in response but with much smaller damper force compared to linear dampers. Finally, the findings in this investigation indicate that the earthquake response of the asymmetric systems with non-linear viscous or VE dampers can be estimated with sufficient accuracy for design applications by analysing the same asymmetric systems with all non-linear dampers replaced by energy-equivalent linear viscous dampers. Copyright © 2003 John Wiley & Sons, Ltd. [source] Extension of a combined analytical/numerical initial value problem solver for unsteady periodic flowINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 9 2002Lawrence J. De Chant Abstract Here we describe analytical and numerical modifications that extend the Differential Reduced Ejector/ mixer Analysis (DREA), a combined analytical/numerical, multiple species ejector/mixing code developed for preliminary design applications, to apply to periodic unsteady flow. An unsteady periodic flow modelling capability opens a range of pertinent simulation problems including pulse detonation engines (PDE), internal combustion engine ICE applications, mixing enhancement and more fundamental fluid dynamic unsteadiness, e.g. fan instability/vortex shedding problems. Although mapping between steady and periodic forms for a scalar equation is a classical problem in applied mathematics, we will show that extension to systems of equations and, moreover, problems with complex initial conditions are more challenging. Additionally, the inherent large gradient initial condition singularities that are characteristic of mixing flows and that have greatly influenced the DREA code formulation, place considerable limitations on the use of numerical solution methods. Fortunately, using the combined analytical,numerical form of the DREA formulation, a successful formulation is developed and described. Comparison of this method with experimental measurements for jet flows with excitation shows reasonable agreement with the simulation. Other flow fields are presented to demonstrate the capabilities of the model. As such, we demonstrate that unsteady periodic effects can be included within the simple, efficient, coarse grid DREA implementation that has been the original intent of the DREA development effort, namely, to provide a viable tool where more complex and expensive models are inappropriate. Copyright © 2002 John Wiley & Sons, Ltd. [source] Recent advances of neural network-based EM-CADINTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 5 2010Humayun Kabir Abstract In this article, we provide an overview of recent advances in computer-aided design techniques using neural networks for electromagnetic (EM) modeling and design applications. Summary of various recent neural network modeling techniques including passive component modeling, design and optimization using the models are discussed. Training data for the models are generated from EM simulations. The trained neural networks become fast and accurate models of EM structures. The models are then incorporated into various optimization methods and commercially available circuit simulators for fast design and optimization. We also provide an overview of recently developed neural network inverse modeling technique. Training a neural network inverse model directly may become difficult due to the nonuniqueness of the input,output relationship in the inverse model. Training data containing multivalued solutions are divided into groups according to derivative information. Multiple inverse submodels are built based on divided data groups and are then combined to form a complete model. Comparison between the conventional EM-based design approach and the inverse design approach has also been discussed. These computer-aided design techniques using neural models provide circuit level simulation speed with EM level accuracy avoiding the high computational cost of EM simulation. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010. [source] A TRIANGULAR MODEL OF DIMENSIONLESS RUNOFF PRODUCING RAINFALL HYETOGRAPHS IN TEXAS,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 4 2003William H. Asquith ABSTRACT: A synthetic triangular hyetograph for a large data base of Texas rainfall and runoff is needed. A hyetograph represents the temporal distribution of rainfall intensity at a point or over a watershed during a storm. Synthetic hyetographs are estimates of the expected time distribution for a design storm and principally are used in small watershed hydraulic structure design. A data base of more than 1,600 observed cumulative hyetographs that produced runoff from 91 small watersheds (generally less than about 50 km2) was used to provide statistical parameters for a simple triangular shaped hyetograph model. The model provides an estimate of the average hyetograph in dimensionless form for storm durations of 0 to 24 hours and 24 to 72 hours. As a result of this study, the authors concluded that the expected dimensionless cumulative hyetographs of 0 to 12 hour and 12 to 24 hour durations were sufficiently similar to be combined with minimal information loss. The analysis also suggests that dimensionless cumulative hyetographs are independent of the frequency level or return period of total storm depth and thus are readily used for many design applications. The two triangular hyetographs presented are intended to enhance small watershed design practice in applicable parts of Texas. [source] CIRSE: A solvation energy estimator compatible with flexible protein docking and design applicationsPROTEIN SCIENCE, Issue 7 2006David S. Cerutti Abstract We present the Coordinate Internal Representation of Solvation Energy (CIRSE) for computing the solvation energy of protein configurations in terms of pairwise interactions between their atoms with analytic derivatives. Currently, CIRSE is trained to a Poisson/surface-area benchmark, but CIRSE is not meant to fit this benchmark exclusively. CIRSE predicts the overall solvation energy of protein structures from 331 NMR ensembles with 0.951 ± 0.047 correlation and predicts relative solvation energy changes between members of individual ensembles with an accuracy of 15.8 ± 9.6 kcal/mol. The energy of individual atoms in any of CIRSE's 17 types is predicted with at least 0.98 correlation. We apply the model in energy minimization, rotamer optimization, protein design, and protein docking applications. The CIRSE model shows some propensity to accumulate errors in energy minimization as well as rotamer optimization, but these errors are consistent enough that CIRSE correctly identifies the relative solvation energies of designed sequences as well as putative docked complexes. We analyze the errors accumulated by the CIRSE model during each type of simulation and suggest means of improving the model to be generally useful for all-atom simulations. [source] Applicability of published data for fatigue-limited designQUALITY AND RELIABILITY ENGINEERING INTERNATIONAL, Issue 8 2009Martin Leary Abstract The use of published fatigue data provides an expedient basis for fatigue-limited engineering design by alleviating the necessity of explicit testing. However, published fatigue data often exhibits incomplete documentation of the associated test conditions. Incomplete documentation introduces uncertainties in fatigue life prediction that may limit the applicability of the published fatigue data for design applications. Characterization of the applicability of published fatigue data is critical for robust fatigue-limited design. However, no quantitative methods have been identified which respond to this requirement. A novel method has been developed to provide a systematic characterization of the applicability of published fatigue data based on internationally recognized standards. This method provides a conceptual mechanism to: identify the applicability of published fatigue test data for specific design scenarios,thereby informing engineers of potential limitations of published data and allowing prioritization of multiple data sources; identify material domains of insufficient applicability,thereby providing a robust basis for identifying beneficial fatigue test programs; compromise between design complexity and the uncertainties inherent in fatigue life prediction; define a framework for the appropriate documentation of published fatigue data. A sample of published fatigue data sources associated with a specific fatigue-limited safety,critical design scenario was assessed by the method presented in this paper. For the majority of the sampled references, the associated documentation was insufficient to allow the fatigue test data to be confidently applied to the subsequent design activity. Copyright © 2009 John Wiley & Sons, Ltd. [source] | ||||||||||