845 research outputs found

    The order-disorder transition in model lipid bilayers is a first-order hexatic to liquid phase transition

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    We characterize the order-disorder transition in a model lipid bilayer using molecular dynamics simulations. We find that the ordered phase is hexatic. In particular, in-plane structures possess a finite concentration of 5-7 disclination pairs that diffuse throughout the plane of the bilayer, and further, in-plane structures exhibit long-range orientational order and short-range translational order. In contrast, the disordered phase is liquid. The transition between the two phases is first order. Specifically, it exhibits hysteresis, and coexistence exhibits an interface with capillary scaling. The location of the interface and its spatial fluctuations are analyzed with a spatial field constructed from a rotational-invariant for local 6-fold orientational order. As a result of finite interfacial tension, there necessarily exist associated forces of assembly between membrane-bound solutes that pre-melt the ordered phase.Comment: Addressed the comments from colleagues, corrected typos, clarified text, updated references. The new draft also contains new results relating to the hexatic phas

    Supporting Special-Purpose Health Care Models via Web Interfaces

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    The potential of the Web, via both the Internet and intranets, to facilitate development of clinical information systems has been evident for some time. Most Web-based clinical workstations interfaces, however, provide merely a loose collection of access channels. There are numerous examples of systems for access to either patient data or clinical guidelines, but only isolated cases where clinical decision support is presented integrally with the process of patient care, in particular, in the form of active alerts and reminders based on patient data. Moreover, pressures in the health industry are increasing the need for doctors to practice in accordance with Âżbest practiceÂż guidelines and often to operate under novel health-care arrangements. We present the Care Plan On-Line (CPOL) system, which provides intranet-based support for the SA HealthPlus Coordinated Care model for chronic disease management. We describe the interface design rationale of CPOL and its implementation framework, which is flexible and broadly applicable to support new health care models over intranets or the Internet

    Innovative drive concept for machining robots

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    In this paper an innovative drive concept for robots to improve their machining capability is presented. As a test bed a two-axis robot is designed and equipped with torque motors with load-sided high resolution encoders in addition to conventional gear motors with harmonic drive gearboxes. The gear motors are used for positioning tasks while the torque motors in particular compensate static and dynamic load-sided angle errors. The model-based control algorithm is decoupled and separately actuates both the servo gear and torque motors. It is shown that a considerable increase of performance is possible when adding the torque motors especially regarding the compensation of dynamic angle errors. The paper will present the design and details of the new drive concept, the modeling basics and first simulation results

    Subacute aluminium intoxication in hemodialysis patients

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    Laboratorium voor ToxicologieKlinische chemie, farmacie en toxicologie in relatie tot effectoren, mediatoren en doelorganen bij ziekteprocessen

    Influence of AFP Process Parameters on the Temperature Distribution Used for Thermal in-process Monitoring

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    Automated Fiber Placement is an important manufacturing process when it comes to aerospace part generation. To minimize the machine downtime, an online monitoring system is necessary to prevent time consuming visual inspection. Therefore, a new thermal in-process monitoring system is integrated. Herewith spotted temperature difference enable the localization of placed tows and detection of defects. The thermal contrast between subsurface and tows depends on different process parameters such as lay-up speed, tooling temperature and compaction pressure. This influence is analyzed and discussed within lay-up studies to gain further knowledge about the different effects to increase the reliability of in-process monitoring as well as AFP processes.Therm-O-PlanNiedersächsisches Vorab, Volkswagen Foundatio

    Correlation between process load and deep rolling induced residual stress profiles

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    Deep rolling is often used as a finishing step after cutting because of its beneficial influence on surface and subsurface properties, which lead to an increase in performance and lifecycle behavior. This manufacturing process is suitable to reduce roughness and to induce compressive residual stresses. As thermal effects only play a minor role in the deep rolling process, it is possible to link the resulting residual stresses to the analytically determined internal process loads. The boundaries of these relationships are investigated on hardened AISI 4140 using different mechanical loads and overlap factors

    Correlation between process load and deep rolling induced residual stress profiles

    Get PDF
    Deep rolling is often used as a finishing step after cutting because of its beneficial influence on surface and subsurface properties, which lead to an increase in performance and lifecycle behavior. This manufacturing process is suitable to reduce roughness and to induce compressive residual stresses. As thermal effects only play a minor role in the deep rolling process, it is possible to link the resulting residual stresses to the analytically determined internal process loads. The boundaries of these relationships are investigated on hardened AISI 4140 using different mechanical loads and overlap factors

    Virtuele communities voorbij de hype: Nieuw inzichten voor managers, marketeers en marktonderzoekers

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    Consumenten leggen steeds vaker contact met elkaar via het Internet. Elektronische discussieforums, mededelingenborden, nieuwsgroepen, e-maillijsten, chatrooms en weblogs bieden consumenten, waar dan ook ter wereld, de mogelijkheid om hun kennis, ervaringen en meningen te delen. De populariteit van deze elektronische contacten tussen consumenten blijkt uit de grote hoeveelheid virtuele communities die georganiseerd zijn rondom consumptiegerelateerde interesses. Dit soort communities vertegenwoordigen uitgebreide netwerken van consumptiekennis en kameraadschap die invloed hebben op consumentengedrag. In dit artikel gaan we in op een aantal nieuwe inzichten ten aanzien van virtuele communities die managers, marketeers en marktonderzoekers beter in staat stellen om strategisch gebruik te maken van de vele mogelijkheden die nu nog vaak onbenut worden gelaten
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