360 research outputs found

    Hubble Diagram Test of Expanding and Static Cosmological Models: The Case for a Slowly Expanding Flat Universe

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    We present a new redshift (RS) versus photon travel time () test including 171 supernovae RS data points. We extended the Hubble diagram to a range of z = 0,0141–8.1 in the hope that at high RSs, the fitting of the calculated RS/ diagrams to the observed RS data would, as predicted by different cosmological models, set constraints on alternative cosmological models. The Lambda cold dark matter (ΛCDM), the static universe model, and the case for a slowly expanding flat universe (SEU) are considered. We show that on the basis of the Hubble diagram test, the static and the slowly expanding models are favored

    Optimal distribution of phosphorus compounds in multi-layered natural fabric reinforced biocomposites

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    Flame retardancy and mechanical performance of multi-layered biocomposites, consisting of polylactic acid (PLA) matrix films and plain-woven flax fabrics as reinforcement, were investigated. Full factorial design (32) was applied to evaluate the effects of the distribution of P and N containing compounds between the matrix and the fibrous carrier. Composition property correlations of the composite constituents (i.e. flax fabrics treated in aqueous solutions of diammonium phosphate and urea with differing ratio and concentrations and matrix films with 0 to 20 wt% ammonium polyphosphate based intumescent flame retardant content) were determined by thermogravimetric analyses and open flame tests. Positive interaction between the composite constituents was revealed for green composites consisting of various combinations of treated fabrics and intumescent PLA systems. The biocomposites flame retarded with a combined approach, i.e. with a balanced distribution of P containing additives between the phases, were found to gain improved mechanical performance and fire retardancy. It was confirmed by tensile testing and electron microscopy as well as by UL-94, limiting oxygen index and cone calorimeter tests. As a conclusion, interpretation is given for the optimum found

    FLAME RETARDED, REINFORCED POLYPROPYLENE TECHNICAL FIBRES

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    A new simple method has been elaborated for increasing the strength of oriented polypropylene fibres by additives. The principle of the process is the incorporation of inorganic fillers (such as talc or CaCO3 ) into polypropylene matrix material in a manner that allows maintaining the stretch ability of the fibre formed in this way. A new halogen free additive system has been developed which contains reactive P, N, Si and Zn derivatives that react with each other in the production line forming a flame retarded polypropylene fibre by reactive extrusion. The influence of the additive system under combustion is based on the formation of a closed intumescent surface layer, that hinders the heat and flammable material transport

    SZTAKI desktop grid: a modular and scalable way of building large computing grids

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    So far BOINC based desktop grid systems have been applied at the global computing level. This paper describes an extended version of BOINC called SZTAKI desktop grid (SZDG) that aims at using desktop grids (DGs) at local (enterprise/institution) level. The novelty of SZDG is that it enables the hierarchical organisation of local DGs, i.e., clients of a DG can be DGs at a lower level that can take work units from their higher level DG server. More than that, even clusters can be connected at the client level and hence work units can contain complete MPI programs to be run on the client clusters. In order to easily create master/worker type DG applications a new API, called as the DC-API has been developed. SZDG and DC-API has been successfully applied both at the global and local level, both in academic institutions and in companies to solve problems requiring large computing power

    Distributed Environment for Efficient Virtual Machine Image Management in Federated Cloud Architectures

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    The use of Virtual Machines (VM) in Cloud computing provides various benefits in the overall software engineering lifecycle. These include efficient elasticity mechanisms resulting in higher resource utilization and lower operational costs. VM as software artifacts are created using provider-specific templates, called VM images (VMI), and are stored in proprietary or public repositories for further use. However, some technology specific choices can limit the interoperability among various Cloud providers and bundle the VMIs with nonessential or redundant software packages, leading to increased storage size, prolonged VMI delivery, stagnant VMI instantiation and ultimately vendor lock-in. To address these challenges, we present a set of novel functionalities and design approaches for efficient operation of distributed VMI repositories, specifically tailored for enabling: (i) simplified creation of lightweight and size optimized VMIs tuned for specific application requirements; (ii) multi-objective VMI repository optimization; and (iii) efficient reasoning mechanism to help optimizing complex VMI operations. The evaluation results confirm that the presented approaches can enable VMI size reduction by up to 55%, while trimming the image creation time by 66%. Furthermore, the repository optimization algorithms, can reduce the VMI delivery time by up to 51% and cut down the storage expenses by 3%. Moreover, by implementing replication strategies, the optimization algorithms can increase the system reliability by 74%

    Nanofibrous solid dosage form of living bacteria prepared by electrospinning

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    The aim of this work was to investigate the suitability of electrospinning for biodrug delivery and to develop an electrospinning-based method to produce vaginal drug delivery systems. Lactobacillus acidophilus bacteria were encapsulated into nanofibers of three different polymers (polyvinyl alcohol and polyvinylpyrrolidone with two different molar masses). Shelf life of the bacteria could be enhanced by the exclusion of water and by preparing a solid dosage form, which is an advantageous and patient-friendly way of administration. The formulations were stored at –20, 7 and 25°C, respectively. Viability testing showed that the nanofibers can provide long term stability for huge amounts of living bacteria if they are kept at (or below) 7°C. Furthermore, all kinds of nanowebs prepared in this work dissolved instantly when they got in contact with water, thus the developed biohybrid nanowebs can provide new potential ways for curing bacterial vaginosis

    ENABLING GENERIC DISTRIBUTED COMPUTING INFRASTRUCTURE COMPATIBILITY FOR WORKFLOW MANAGEMENT SYSTEMS

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    Solving workflow management system’s Distributed Computing Infrastructure (DCI) incompatibility and their workflow interoperability issues are very challenging and complex tasks. Workflow management systems (and therefore their workflows, workflow developers and also their end-users) are bounded tightly to some limited number of supported DCIs, and efforts required to allow additional DCI support. In this paper we are specifying a concept how to enable generic DCI compatibility for grid workflow management systems (such as ASKALON, MOTEUR, gUSE/WS-PGRADE, etc.) on job and indirectly on workflow level. To enable DCI compatibility among the different workflow management systems we have developed the DCI Bridge software solution. In this paper we will describe its internal architecture, provide usage scenarios to show how the developed service resolve the DCI interoperability issues between various middleware types. The generic DCI Bridge service enables the execution of jobs onto the existing major DCI platforms (such as Service Grids (Globus Toolkit 2 and 4, gLite, ARC, UNICORE), Desktop Grids, Web services, or even cloud based DCIs)
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