394 research outputs found

    A lattice Boltzmann study of phase separation in liquid-vapor systems with gravity

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    Phase separation of a two-dimensional van der Waals fluid subject to a gravitational force is studied by numerical simulations based on lattice Boltzmann methods (LBM) implemented with a finite difference scheme. A growth exponent α=1\alpha=1 is measured in the direction of the external force.Comment: To appear in Communications in Computational Physics (CiCP

    ENERGY CONSUMPTION OF MOBILE PHONES

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    Battery consumption in mobile applications development is a very important aspect and has to be considered by all the developers in their applications. This study will present an analysis of different relevant concepts and parameters that may have an impact on energy consumption of Windows Phone applications. This operating system was chosen because limited research related thereto has been conducted, even though there are related studies for Android and iOS operating systems. Furthermore, another reason is the increasing number of Windows Phone users. The objective of this research is to categorise the energy consumption parameters (e.g. use of one thread or several threads for the same output). The result for each group of experiments will be analysed and a rule will be derived. The set of derived rules will serve as a guide for developers who intend to develop energy efficient Windows Phone applications. For each experiment, one application is created for each concept and the results are presented in two ways; a table and a chart. The table presents the duration of the experiment, the battery consumed in the experiment, the expected battery lifetime, and the energy consumption, while the charts display the energy distribution based on the main threads: UI thread, application thread, and network thread

    A formal method for rule analysis and validation in distributed data aggregation service

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    The usage of Cloud Serviced has increased rapidly in the last years. Data management systems, behind any Cloud Service, are a major concern when it comes to scalability, flexibility and reliability due to being implemented in a distributed way. A Distributed Data Aggregation Service relying on a storage system meets these demands and serves as a repository back-end for complex analysis and automatic mining of any type of data. In this paper we continue our previous work on data management in Cloud storage. We present a formal approach to express retrieval and aggregation rules with a compact, yet powerful tool called Rule Markup Language. Our extended solution proposes a standard form to schemes and uses the tool to match the rules to the XML form of the structured data in order to obtain the unstructured entries from BlobSeer data storage system. This allows the Distributed Data Aggregation Service (DDAS) to bypass several steps when processing a retrieval request. Our new architecture is more loosely-coupled with a separate module, the new tool, used fo

    Meta-scheduling Issues in Interoperable HPCs, Grids and Clouds

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    Over the last years, interoperability among resources has been emerged as one of the most challenging research topics. However, the commonality of the complexity of the architectures (e.g., heterogeneity) and the targets that each computational paradigm including HPC, grids and clouds aims to achieve (e.g., flexibility) remain the same. This is to efficiently orchestrate resources in a distributed computing fashion by bridging the gap among local and remote participants. Initially, this is closely related with the scheduling concept which is one of the most important issues for designing a cooperative resource management system, especially in large scale settings such as in grids and clouds. Within this context, meta-scheduling offers additional functionalities in the area of interoperable resource management, this is because of its great agility to handle sudden variations and dynamic situations in user demands. Accordingly, the case of inter-infrastructures, including InterCloud, entitle that the decentralised meta-scheduling scheme overcome issues like consolidated administration management, bottleneck and local information exposition. In this work, we detail the fundamental issues for developing an effective interoperable meta-scheduler for e-infrastructures in general and InterCloud in particular. Finally, we describe a simulation and experimental configuration based on real grid workload traces to demonstrate the interoperable setting as well as provide experimental results as part of a strategic plan for integrating future meta-schedulers

    Dynamic modelling and nonlinear model predictive control of a fluid catalytic cracking unit

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    The paper presents the application of two nonlinear model predictive control (NMPC) approaches: quasi-infinite-horizon nonlinear MPC (QIHNMPC) and moving horizon estimator nonlinear MPC (MHE-NMPC) to the Fluid Catalytic Cracking Unit (FCCU). A complex dynamic model of the reactor–regenerator–fractionator system is developed and subsequently used in the controller. The novelty of the model consists in that besides the complex dynamics of the reactor–regenerator system, it also includes the dynamic model of the fractionator, as well as a five lumps kinetic model for the riser. Tight control is achieved using the QIHNMPC approach. The MHE-NMPC considers important features of a real-time control algorithm, resulting in a framework for practical NMPC implementation, such as: state and parameter estimation and efficient solution of the optimisation problem. In the NMPC approach, only measurements available in practice are considered, whereas the rest of the states are estimated together with uncertain model parameters, via MHE technique. Using an efficient numerical implementation based on the multiple shooting algorithm real-time feasibility of the approach is achieved. The incentives of the proposed approaches are assessed on the simulated industrial FCCU

    RESEARCH ON INDUSTRIALIZATION IN OBTAINING BIOFERTILIZERS AND BIOFUELS FROM SEAWEED

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    Obtaining biofertilizers and biofuels from organic products has been of great interest in recent years and is an important step in combating pests and reducing soil chemicals. Seaweed is an great agent in reduction pollution, in the textile industry, in the manufacture of pulp and paper, in distillation, in petrochemistry, metallurgy, chemistry, food, pharmaceuticals, as well as in agriculture as biofertilizers.This article presents stages of research worldwide on the potential of industrialization in obtaining biofuels and biofertilizers from seaweed.The paper highlights technologies and processing methods in obtaining future biofertilizers and biofuels with a low impact on new climate change felt strongly on agriculture

    Metformin plus PIAF combination chemotherapy for hepatocellular carcinoma

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    Objectives: Metformin, the most used oral antidiabetic drug for the treatment of type 2 diabetus mellitus, has proved encouraging results when used in the treatment of various types of cancer such as triple-negative breast cancer. Despite compelling evidence of a role of metformin as an anticancer drug, the mechanisms by which metformin exerts its oncostatic actions are not fully understood yet. Therefore, we tried to bring new insights by analyzing the anti-neoplastic effect of metformin for hepatocellular carcinoma-derived stem-like cells treated with conventional combination chemotherapy. Methods: Cancer stem-like cells previusly isolated from a hepatocellular carcinoma biopsy were treated with metformin, PIAF chemotherapy regimen and the combination of these two protocols. Measurements of lipid peroxidation, reduced glutathione, fluorescein diacetate and proliferation rates were determined, apart from the autophagy assay and apoptosis determination by chip flow cytometry. Results: Metformin alone and especially metformin in association with PIAF increases oxidative stress within the cells by increasing the levels of lipid peroxids as well as decreasing the levels of reduced glutathione. The MTT cell proliferation assay showed decreased prolife­ration rates for the arm treated with metformin and with the combination of drugs in comparison with the control arm, proving high correlation with the oxidative stress results. The autophagy assay and determination of apoptosis by chip flow cytometry confirmed the results obtained in the previous assays. Conclusion: Metformin could be used in chemotherapy treatments to induce reactive oxygen species and increase the cytostatics effects within the tumor cell. Still, further experiments must be carried out on murine models before we can move on and use this drugs in the adjuvant setting for unresectable primary liver cancer

    Finite difference lattice Boltzmann model with flux limiters for liquid-vapor systems

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    In this paper we apply a finite difference lattice Boltzmann model to study the phase separation in a two-dimensional liquid-vapor system. Spurious numerical effects in macroscopic equations are discussed and an appropriate numerical scheme involving flux limiter techniques is proposed to minimize them and guarantee a better numerical stability at very low viscosity. The phase separation kinetics is investigated and we find evidence of two different growth regimes depending on the value of the fluid viscosity as well as on the liquid-vapor ratio.Comment: 10 pages, 10 figures, to be published in Phys. Rev.

    Dynamique des populations et mosaïque forestière en hêtraie-sapinière naturelle préservée. une comparaison entre Vosges et Carpates

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    A comparison of population dynamics and forest architecture has been carried in two well preserved beech-fir forests of Europe, in the Carpates and in the Vosges. The two reserves present marked differences in climate, soils and local environment. We show that beech dominates all the strata. In a situation of valley bottom (Carpates), its shady canopy explains growth patterns of understorey. Beech and fir present alternating phases of suppression and re-growth. Seedlings and saplings grow preferentially at the edges of adult canopies and in gaps. In the Vosges, slope induces imbricated crowns, and lateral light inputs are higher than in the Carpates. However regeneration is less dense because of less favourable soils and climate, and located preferentially in the neighbourhood of gaps. Both forests present a fine-grained architecture of eco-units, which increase resistance to disturbancesUne recherche comparative de sylvigénèse en hêtraie-sapinière a été entreprise dans deux réserves forestières intégrales, présentant des différences écologiques marquées dans les Hautes Vosges et les Carpates orientales. Les données recueillies concernent la structure des populations de ligneux (hêtre, sapin, épicéa, érable sycomore) et l'organisation architecturale des mosaiques forestières, par deux profils architecturaux, qui illustrent un aspect des situations sylvigénétiques rencontrées dans ces forêts de montagnes. Les principaux résultats démontrent que le hêtre domine les strates des deux forêts. En situation de fond de vallon (Carpates), l'ombrage qui résulte d'une canopée dense impose aux arbustes dominés (jeunes hêtres, mais surtout sapins) une croissance en palier parfois très longue, qui explique les situations préférentielles des semis en bordure des éco-unités matures ou dans les trouées. En situation de pente (Vosges), l'architecture en pile d'assiette des dominants, qui résulte de l'importance des apports lumineux latéraux, raccourcit cette attente. Mais les conditions plus rudes rencontrées dans cette réserve diminuent les densités à tous les étages. L'architecture des deux réserves montre une mosaïque fine d'éco-unités à différentes hauteurs, composées de plusieurs espèces ligneuses atteignant parfois des dimensions impressionnantes. L'ensemble est très stable, en dépit des aléas climatiques

    Centralized micro-clouds: an infrastructure for service distribution in collaborative smart devices

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    In the current information-driven society, the massive use and impact of communications and mobile devices challenge the design of communication networks. This highlights the emergency of a new Internet structure namely the Internet of Things that refers to the transformation of physical objects to smart objects and their communication. Based on that the communication of such objects will offer an augmented infrastructure that is formed dynamically and on the fly based on transient links among objects. This is the concept behind cloud computing, to provide a computer-based environment where various services are available to be consumed by everyday users, anywhere and at anytime. Our vision encompasses a dynamic micro-cloud environment that is formed from devices that share computational power. This encompasses inter-linked smart objects and smart mobile devices available from a smart environment that can be formed dynamically. The proposed micro-cloud notion will be of apparent significance to maintain the required quality of service in dynamic scenarios such as those found in emergency and disaster situations. To represent such system we are focused on the development of such architecture into a novel simulation toolkit that allows the replication of Internet of Things scenarios
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