1,322 research outputs found

    Exploiting Template Metaprogramming to customize an object-oriented operating system

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    Nowadays, the growing complexity of embedded systems demands for configurability, variability and reuse. Conditional compilation and object-orientation are two of the most applied approaches in the management of system variability. While the former increases the code management complexity, the latter leverages the needed modularity and adaptability to simplify the development of reusable and customizable software at the expense of performance and memory penalty. This paper shows how C++ TMP (Template Metaprogramming) can be applied to manage the variability of an object-oriented operating system and at the same time get ride out of the performance and memory footprint overhead. In doing so, it will be statically generated only the desired functionalities, thus ensuring that code is optimized and adjusted to application requirements and hardware resources.Fundação para a Ciência e a Tecnologia (FCT

    Experiments with embedded system design at UMinho and AIT

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    Nowadays, embedded systems are central to modern life, mainly due to the scientific and technological advances of the last decades that started a new reality in which the embedded systems market has been growing steadily, along with a monthly or even weekly emergence of new products with different applications across several domains. This embedded system ubiquity was the drive for the following question ”Why should we focus on embedded systems design?” that was answered in [1, 2] with the following points: (1) high and fast penetration in products and services due to the integration of networking, operating system and database capabilities, (2) very strategic field economically and (3) a new and relatively undefined subject in academic environment. Other adja- cent questions have been raised such as ”Why is the design of embedded systems special?”. The answer for this last question is based mainly on several problems raised by the new technologies, such as the need for more human resources in specialized areas and high learning curve for system designers. As pointed in [1], these problems can prevent many companies from adopting these new technologies or force them not to respond timely in mastering these technological and market challenges. In this paper, it is described how staff at ESRG-UMinho 1 and ISE-AIT 2 faced the embedded systems challenges at several levels. It starts to de- scribe the development of the educational context for the new technolo- gies and show how our Integrated Master Curriculum in Industrial Elec- tronics and Computer Engineering has been adapted to satisfy the needs of the major university customers, the industry

    ClimaWin : an intelligent window for optimal ventilation and minimum thermal loss

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    In this paper the ClimaWin concept is introduced. The ClimaWin project's main goals are to improve both indoor air quality and the energy efficiency of new and refurbished buildings, through the use of novel green smart windows. Generally, in order to improve windows' energy efficiency better insulation materials are used in windows frames and glasses. However, this approach leads to a severe deterioration of indoor air quality (IAQ) especially in buildings that are not equipped with heating, ventilation and air conditioning (HVAQ) systems. The Climawin windows do not require wires neither for power nor for communications. The window is powered through a battery (for blind operation) and a solar panel, which makes it an ideal solution for retrofitting. In order to achieve the energy efficiency requirements, the Climawin system hardware, the microcontroller software architecture and the radio communication strategy were designed for low power consumption. Furthermore, all the information about the system status can be monitored and actuated using intuitive graphical applications developed for PCs and Android OS smartphones. A remote database keeps all the relevant information about the system, making it easy to detect any anomaly or even to adjust the control algorithm parameters from a remote location. A full-set of web services are also provided in order to simplify the communication with home automation systems.Fundação para a Ciência e a Tecnologia (FCT

    Immobilization of a Commercial Lipase from Penicillium camembertii (Lipase G) by Different Strategies

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    The objective of this work was to select the most suitable procedure to immobilize lipase from Penicillium camembertii (Lipase G). Different techniques and supports were evaluated, including physical adsorption on hydrophobic supports octyl-agarose, poly(hydroxybutyrate) and Amberlite resin XAD-4; ionic adsorption on the anionic exchange resin MANAE-agarose and covalent attachment on glyoxyl-agarose, MANAE-agarose cross-linked with glutaraldehyde, MANAE-agarose-glutaraldehyde, and epoxy-silica-polyvinyl alcohol composite. Among the tested protocols, the highest hydrolytic activity (128.2 ± 8.10 IU·g−1 of support) was achieved when the lipase was immobilized on epoxy-SiO2-PVA using hexane as coupling medium. Lipase immobilized by ionic adsorption on MANAE-agarose also gave satisfactory result, attaining 55.6 ± 2.60 IU·g−1 of support. In this procedure, the maximum loading of immobilized enzyme was 9.3 mg·g−1 of gel, and the highest activity (68.8 ± 2.70 IU·g−1 of support) was obtained when 20 mg of protein·g−1 was offered. Immobilization carried out in aqueous medium by physical adsorption on hydrophobic supports and covalent attachment on MANAE-agarose-glutaraldehyde and glyoxyl-agarose was shown to be unfeasible for Lipase G. Thermal stability tests revealed that the immobilized derivative on epoxy-SiO2-PVA composite using hexane as coupling medium had a slight higher thermal stability than the free lipase

    Triagem de suportes orgânicos e protocolos de ativação na imobilização e estabilização de lipase de Thermomyces lanuginosus

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    Lipase from Thermomyces lanuginosus was covalently immobilized on activated poly-hydroxybutyrate, sugarcane bagasse and the chemically modified hybrid hydrogel chitosan-alginate prepared by different strategies. Among the tested supports, chitosan-alginate chemically modified with 2,4,6-trinitrobenzenesulfonic acid rendered derivatives with the highest hydrolytic activity and thermal-stability, 45-fold more stable than soluble lipase and was then selected for further studies. The pH of maximum activity was similar for both immobilized and free lipase (pH 8.0) while optimum temperature was 5 - 10 ºC higher for the immobilized lipase. Higher yields in the butyl butyrate synthesis were found for the derivatives prepared by activation with glycidol and epichlorohydrin

    Produção de concentrados de ácidos graxos por hidrólise de óleos vegetais mediada por lipase vegetal

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    The aim of this work was to verify the ability of enzymatic crude extract from dormant castor bean seeds to yield concentrated fatty acids by hydrolysis of polyunsaturated vegetable oils such as corn and sunflower. The enzymatic extract exhibited higher activity towards corn oil, which was selected for further studies to determine optimum hydrolysis conditions by factorial design. Maximum hydrolysis percentage (≈84%) was reached at 60% wt. oil:buffer acetate 100 mM pH 4.5, 33 ºC and 5.0% wt. of crude extract after 70 min of reaction. These results suggest that the use of low-cost lipase from castor bean seeds has potential for oil hydrolysis

    Modification of oils and fats by biotransformation

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    The oleochemical industry has a permanent interested in controlling the physical, functional and organoleptical properties of their products and in producing useful derivatives from their raw materials. The potential of biotechnology for developing novel or well-known products at more competitive costs meets the need of this industrial segment in expanding their goals. In this work some technical aspects, problems and perspectives related to the production of oil and fat derivatives using biotransformation techniques are discussed. Particular emphasis is given to the description of biotransformation processes using lipase as catalyst, in view of the great versatility of this enzyme class to mediate typical reactions in this technological sector.14615

    Modified Brans-Dicke theory of gravity from five-dimensional vacuum

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    We investigate, in the context of five-dimensional (5D) Brans-Dicke theory of gravity, the idea that macroscopic matter configurations can be generated from pure vacuum in five dimensions, an approach first proposed in the framework of general relativity. We show that the 5D Brans-Dicke vacuum equations when reduced to four dimensions lead to a modified version of Brans-Dicke theory in four dimensions (4D). As an application of the formalism, we obtain two five-dimensional extensions of four-dimensional O'Hanlon and Tupper vacuum solution and show that they lead two different cosmological scenarios in 4D.Comment: 9 page
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