6,000 research outputs found

    The role of Computer Aided Process Engineering in physiology and clinical medicine

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    This paper discusses the potential role for Computer Aided Process Engineering (CAPE) in developing engineering analysis and design approaches to biological systems across multiple levels—cell signalling networks, gene, protein and metabolic networks, cellular systems, through to physiological systems. The 21st Century challenge in the Life Sciences is to bring together widely dispersed models and knowledge in order to enable a system-wide understanding of these complex systems. This systems level understanding should have broad clinical benefits. Computer Aided Process Engineering can bring systems approaches to (i) improving understanding of these complex chemical and physical (particularly molecular transport in complex flow regimes) interactions at multiple scales in living systems, (ii) analysis of these models to help to identify critical missing information and to explore the consequences on major output variables resulting from disturbances to the system, and (iii) ‘design’ potential interventions in in vivo systems which can have significant beneficial, or potentially harmful, effects which need to be understood. This paper develops these three themes drawing on recent projects at UCL. The first project has modeled the effects of blood flow on endothelial cells lining arteries, taking into account cell shape change resulting in changes in the cell skeleton which cause consequent chemical changes. A second is a project which is building an in silico model of the human liver, tieing together models from the molecular level to the liver. The composite model models glucose regulation in the liver and associated organs. Both projects involve molecular transport, chemical reactions, and complex multiscale systems, tackled by approaches from CAPE. Chemical Engineers solve multiple scale problems in manufacturing processes – from molecular scale through unit operations scale to plant-wide and enterprise wide systems – so have an appropriate skill set for tackling problems in physiology and clinical medicine, in collaboration with life and clinical scientists

    Comparison of reusable insulation systems for cryogenically-tanked earth-based space vehicles

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    Three reusable insulation systems concepts were developed for use with cryogenic tanks of earth-based space vehicles. Two concepts utilized double-goldized Kapton (DGK) or double-aluminized Mylar (DAM) multilayer insulation (MLI), while the third utilized a hollow-glass-microsphere, loadbearing insulation (LBI). Thermal performance measurements were made under space-hold (vacuum) conditions for insulating warm boundary temperatures of approximately 291 K. The resulting effective thermal conductivity was approximately 0.00008 W/m-K (W = weight,Kg; m = measured; K = temperature) for the MLI systems (liquid hydrogen test results) and 0.00054 W/m-K for the LBI system (liquid nitrogen test results corrected to liquid hydrogen temperature)

    Calibration of a conceptual rainfall-runoff model using simulated annealing

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    Simulated annealing (Kirkpatrick et al, 1983) is used to estimate the parameters of a mathematical model that predicts the water yield from a catchment. The calibration problem involves finding the global minimum of a multivariate function that has many extraneous local minima, a situation in which conventional optimisation methods are ineffective. The objective function which quantifies discrepancies between the computed and observed streamflows must be carefully selected to satisfy the least square assumptions. Several published simulated annealing algorithms have been implemented, tested and evaluated using standard test functions. Appropriate cooling schedules are found for each algorithm and test function investigated. The number of function evaluations required to find the minimum is compared to published results for the test functions using either simulated annealing and other global optimisation methods. A new simulated annealing algorithm based on the Hooke and Jeeves (1961) pattern search method is developed and compared with existing algorithms from the literature

    Combining Consumer Valuation Research with Sensory Science Techniques: A Laboratory Experiment

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    In this research, we integrated an experimental auction with sensory science techniques—namely, trained sensory panels used to analyze the sensory attributes of wines—to examine the effects of objective and sensory information in the market for California-produced Cabernet Sauvignons. The experiment permitted observation of consumer valuation for sensory attributes of wine, appellations, expert ratings, and wineries. Participants submitted bids each time they received new information about the wines. The balanced experimental design permits evaluation of the effects of consumer characteristics on attribute valuation. We had 236 people participate in the research, which consisted of nine rounds of bidding and one round of hedonic liking scores. Rounds 5-9 repeated the structure of information released in rounds 1-4, but added sensory information, yielding 472 observations for each type of information (e.g. appellation, expert rating, winery). We obtain a total of 8496 valuations, or bids and 944 hedonic “liking” ratings, as well as demographic information, wine consumption data, and a wine knowledge score for each consumer. The results of the research agree with many of the previously held notions about valuation of wine by consumers. Participants value Cabernet Sauvignons from Napa Valley and Sonoma County and their sub-appellations more than wines labeled with the California appellation. Bids for wines rated by experts such as the Wine Advocate (Robert Parker) or Wine Spectator increased as the experts’ ratings increased. However, we also find that consumer characteristics are very important in explaining WTP for wine attributes. The contributions of prestigious appellations to the value of Cabernet Sauvignons depended on consumer characteristics. Willingness to pay was highly correlated with sensory evaluation, but even after tasting the wine, appellation and expert ratings still mattered for WTP. Overall, the research describes a significant amount of heterogeneity in the preferences for sensory characteristics of wine, and that individual characteristics systematically explain many of the differences in valuation of wine attributes.Experimental Economics, Willingness to Pay, WTP, Wine, Consumer Valuation, Hedonic Pricing, Sensory Analysis, Demand and Price Analysis, Food Consumption/Nutrition/Food Safety, Marketing, Research Methods/ Statistical Methods,

    Experimental investigation of liquid sloshing in a scale-model Centaur liquid-hydrogen tank

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    Liquid sloshing in scale model Centaur liquid hydrogen tan
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