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Design Aspects (design + aspect)
Selected AbstractsUsability and Safety of Ventricular Assist Devices: Human Factors and Design AspectsARTIFICIAL ORGANS, Issue 9 2009Lorenz Geidl Abstract The purpose of this study was the investigation of the usability and ergonomics of ventricular assist devices (VADs) in everyday usage. Patients with four different VAD types were observed. After implantation, instruction, and discharge from the hospital, the patients returned on a regular basis to the outpatient clinic, where the investigation took place. Data collection took place in two phases. In phase I home-released VAD patients were asked about perceived problems with the system at home. Additionally health-care professionals were interviewed to gather information on frequent VAD inconveniences and shortcomings. This inquiry resulted in a standardized self-assessment questionnaire and a manual skill test, which were performed in phase II by the whole collective (16 patients and ongoing). As a result, 38% of the patients disconnected parts of their system unintentionally at least once. All of them ascribed this problem to their own carelessness. Thirty-eight percent had to replace a cable. Seventy-five percent desired an additional cable strain relief. Thirty-eight percent suffered from rubbing of parts on the body. Sixty-three percent used a separate repository aside from the factory-provided transportation systems. The overall noise emission (pump, ventilators, and alarms) annoyed 56%; however, for 32% the alarm signals were too quiet to wake them up. No correlation between the assessed manual skills and the number of adverse events was found. To conclude, this preliminary study revealed considerable potential for improvements in the usability of ventricular assist systems. [source] Target-Family-Oriented Focused Libraries for Kinases,Conceptual Design Aspects and Commercial AvailabilityCHEMBIOCHEM, Issue 3 2005Olaf Prien Dr. Tailor-made libraries may increase the likelihood of identifying potential lead candidates in early drug-discovery phases. That at least 12 commercial vendors offer their services in providing compound collections of tentative kinase inhibitors reflects the growing interest in kinases within the pharmaceutical industry. Some conceptual design approaches for focused library design for the kinase family are reviewed, and the design concepts of these commercialized libraries is discussed. [source] Design aspects of satellite,cellular hybrid wireless systemsINTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING, Issue 2 2002Tamer ElBatt Abstract In this paper we investigate various issues related to the design of satellite,cellular hybrid systems. First, we review the fundamental problems of channel partitioning and call admission/assignment. Second, we study the impact of different frequency reuse constraints, in both layers, on the optimum channel partitioning. Third, we investigate, analytically and via simulation, the effect of reducing the cell size. We emphasize the blocking-forced termination probabilities trade-off for pure cellular and satellite,cellular hybrid systems. Accordingly, an optimization problem with respect to the cell size is formulated. Finally, we search for the optimum dynamic call re-assignment policy that improves the system capacity at the expense of the complexity associated with tearing down a connection in one system and setting-up an alternative one in the other system. For a small hybrid system, we characterized the optimum re-assignment policies that minimize the blocking probability, dropping probability, and a weighted cost function of these probabilities. Copyright © 2002 John Wiley & Sons, Ltd. [source] Archaeological Reconnaissance of the 1865 American-Built Sub Marine Explorer at Isla San Telmo, Archipielago de las Perlas, PanamaINTERNATIONAL JOURNAL OF NAUTICAL ARCHAEOLOGY, Issue 2 2006James P. Delgado A wrecked submarine lying in the inter-tidal zone of Isla San Telmo, off Panama's coast, has been identified as Sub Marine Explorer, a rare surviving example of a mid-19th-century submersible. One of the world's first successful lock-out dive-chambers, the craft had a fatal design aspect that ultimately harmed its crew and may have killed the builder through the effects of pressure. Documentation of the submarine provides a detailed understanding of this technologically advanced but flawed craft. © 2006 The Author [source] Design Considerations for Plate and Frame Ultrafiltration Modules by Computational Fluid Dynamics Analysis,THE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 3 2006Mauro M. Dal-Cin Abstract Pressure and flow maldistributions were studied in a full-scale industrial plate and frame ultrafiltration module, operating in a Z flow pattern, for the recovery of used motor oils. Solutions were obtained using (1) a three-dimensional solution of the Navier-Stokes equation using computational fluid dynamics and (2) Bernoulli's equation and a momentum balance in one dimension. Fluid decelerations and accelerations generated pressure increases and decreases in the distributor and collector, respectively, biasing the flow distribution to the last channel. Several modifications to the original design were evaluated; the most effective was larger distributor and collector diameters, which greatly improved the uniformity of the flow distribution and transmembrane pressure, and reduced the overall pressure drop in a bank. A variable diameter distributor and collector module was designed using the 1-D model. Flow distribution was significantly improved but also yielded an undesirable overall higher pressure drop and a pressure maldistribution in the bank. The maldistribution of the main inlet manifold to the distributors in the first bank was strongly dependent on the module design. The flow distribution across the width of a channel became uniform within a short distance, essentially eliminating the need to consider this design aspect any further. Flows at the bank outlets, and hence inlets of the following bank, showed uniform lateral distribution in all cases, suggesting that future modelling work can be limited to a fraction of the module width, based on symmetry, in order to gain computational efficiency. On a étudié les mauvaises distributions de pression et d'écoulement dans un module d'ultrafiltration à plateaux et à cadres à l'échelle industrielle, fonctionnant dans un schéma d'écoulement en Z, pour la récupération des huiles de moteurs usées. Des solutions ont été obtenues avec (1) une solution tridimensionnelle de l'équation de Navier-Stokes utilisant la mécanique des fluides par ordinateur, et (2) l'équation de Bernoulli et un bilan de quantité de mouvement unidimensionnel. Les décélérations et accélérations de fluide entraînent des augmentations et diminutions de pression dans le distributeur et le collecteur, respectivement, ce qui fausse la distribution d'écoulement dans le dernier canal. On a évalué plusieurs modifications du concept original; la plus efficace sont des diamètres de distributeur et de collecteur plus larges, qui permettent d'améliorer grandement l'uniformité de la distribution d'écoulement et la pression transmembranaire, et qui réduisent la perte de charge globale dans une batterie. Un module de distributeur et de collecteur de diamètres variables a été conçu au moyen du modèle 1D. La distribution d'écoulement est significativement améliorée mais cause une perte de charge globale plus grande indésirable et une mauvaise distribution de pression dans la batterie. La mauvaise distribution du manifold d'entrée principal vers les distributeurs dans la première batterie est fortement dépendante de la conception du module. La distribution d'écoulement dans toute la largeur d'un canal devient uniforme sur une courte distance, éliminant essentiellement le besoin d'approfondir cet aspect de la conception. L'écoulement en sortie de batteries et donc à l'entrée des batteries suivantes montre une distribution latérale uniforme dans tous les cas, ce qui suggère que le travail de modélisation futur peut se limiter à une fraction de la largeur du module, pour des raisons de symétrie, pour gagner de l'efficacité numérique. [source] Auctioning greenhouse gas emissions permits in Australia,AUSTRALIAN JOURNAL OF AGRICULTURAL & RESOURCE ECONOMICS, Issue 2 2010Regina Betz The allocation of permits is an important design aspect of an emissions trading scheme. Traditionally, governments have favoured the free allocation of greenhouse gas permits based on individual historical emissions (,grandfathering') or industry benchmark data. Particularly in the European Union (EU), the free allocation of permits has proven complex and inefficient and the distributional implications are politically difficult to justify; auctioning emissions permits has therefore become more popular. The EU is now moving to auction more than 50 per cent of all permits in 2013, and in the US the Regional Greenhouse Gas Initiative (RGGI) has begun auctioning more than 90 per cent of total allowances. Another case in point is the Australian proposal for a Carbon Pollution Reduction Scheme (CPRS), which provides for auctioning a significant share of total permits. This paper discusses the proposed Australian CPRS's auction design. A major difference to other emissions trading schemes is that the CPRS plans to auction multiple vintages of emissions permits simultaneously. [source] Allocating treatment options to patient profiles: clinical art or science?ADDICTION, Issue 5 2006Gerhard Bühringer ABSTRACT Background For many researchers, the disappointing results of Project MATCH were the death blow for any further activities in the field of patient,treatment interactions. On the other hand, we have an increased knowledge of patient heterogeneity and a greater variety of treatment options than before, and allocation guidelines for an ongoing process of patient-placement decisions are of high practical relevance. Aims To analyse deficits in the current research and to provide suggestions for future action. Findings It is argued that (1) certain major design aspects of Project MATCH and other research studies,such as stringent patient exclusion criteria and low treatment ,dosage',minimize the chances of detecting possible patient,treatment interactions and (2) Project MATCH obscures our view of previous treatment-allocation research findings., Conclusions Several research strategies and specific research topics are suggested for (1) improving the theoretical and methodological basis for detecting possible patient,treatment interactions and (2) stimulating research on major treatment decision needs, such as site, setting, time in treatment (extensiveness and intensity), service components and specific treatment modules. More international research cooperation is needed to clarify the inconsistent findings. [source] Design of distributed controllers with constrained and noisy linksINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 18 2006Shengxiang Jiang Abstract In this paper we consider some design aspects of distributed controllers that guarantee a ,, performance level. In particular, we consider two design problems. First, is the case where, without loss of generality, there are two distributed subcontrollers connected to a (generalized) plant and the interest is placed in minimizing the number of noise-free (and dynamics free) communication channels between the subcontrollers needed to provide a given performance. The second is the case where, given a distributed controller designed in the first case, communication noise is present and we seek an optimal choice of the communication signals to guarantee a performance level while keeping the communication signal to noise power limited. We take a linear matrix inequality (LMI) approach to provide solution procedures to these problems and present examples that demonstrate their efficiency. Copyright © 2006 John Wiley & Sons, Ltd. [source] What about Design Newness?THE JOURNAL OF PRODUCT INNOVATION MANAGEMENT, Issue 6 2009Investigating the Relevance of a Neglected Dimension of Product Innovativeness In several industries, new products are very similar in functional features but compete on their unique design. Firms like Alessi, Apple, Bang & Olufsen, Dyson, or Kartell all follow a design-driven innovation approach and use their products' visual appearance as the main mean for differentiation. In spite of this, design newness is never discussed among the dimensions of product innovativeness. Instead, conceptualizations of product innovativeness mostly focus on a product's technical newness or the changes it implies for the innovating firm or for the market it enters. This paper seeks to build an argument for why design newness should be considered as a dimension of product innovativeness. In addition to providing conceptual rationale, empirical evidence is offered on the influence of design newness on sales performance across a product's life cycle. To be able to put the findings into perspective, the performance effects of design newness are compared with those of technical newness. As several products exemplify that design newness and technical newness can go hand in hand, not only direct performance effects but also interaction effects between both newness dimensions are investigated. The arguments are tested on a sample of 157 new cars launched between 1978 and 2006 in Germany. The automobile industry is selected because of the strategic role of both technical and design aspects in product innovation. Putting a focus on this industry also has the advantage that historical information on car specifics and objective sales data over time are accessible. The results emphasize that both design and technical newness are important drivers of car sales. However, the effects differ widely across the product life cycle. While design newness has a positive impact right after the introduction and persists in strength over time, technical newness drives sales with a lagged effect and decreases toward the end of the life cycle. The test of a combined influence of design newness and technical newness on sales performance produces no significant results. These results open interesting avenues for future research on product innovativeness in general and design newness in particular. For management practice, the findings emphasize the importance of overall product innovativeness, clarify the different performance effects of design and technical newness across the product life cycle, and show the value of creating a unique visual product appearance to positively trigger product diffusion. [source] Prediction of the Removal Efficiency of a Novel Two-Stage Hybrid Scrubber for Flue Gas DesulfurizationCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 1 2006A. Bandyopadhyaya Abstract Emission of SO2 from various industrial sources occurs in varying concentrations and quantities. The operation of scrubbers as SO2 control devices is getting more and more attention as pollution control regulations are tightened. Experimental investigations on the scrubbing of SO2 in a novel two-stage hybrid (spray-cum-bubble column) scrubber using water and dilute sodium alkali are reported. Empirical and semi-empirical correlations are developed for the prediction of the performances of the bubble and the spray sections in terms of various pertinent variables of the system for water and alkaline scrubbing, respectively. The contribution of the mass transfer enhancement factor towards the removal of SO2 has been exploited while developing the semi-empirical correlation for the prediction of performance in alkaline scrubbing. The predicted values are in excellent agreement with the experimental values. Finally, the operating features of the scrubber and design aspects are discussed in order to develop our understanding for practical applications. [source] Intermediate Temperature Reversible Fuel CellsINTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 2 2007Singaravelu Elangovan Electrolysis of water produces high-purity hydrogen directly, with no need for additional clean-up process. Efficiency and cost of electrolysis are favorable with high-temperature steam electrolyzers where a portion of the required energy can be supplied as thermal energy. With the similarity in requirements, much of the materials and designs aspects for the high-temperature electrolyzers have been derived from solid oxide fuel cell development. Lanthanum gallate electrolyte-based cells were evaluated in fuel cell and electrolysis modes of operation. A modified nickel anode is shown to lower the reactivity with the gallate. [source] | |||||||||||||||||||