944 resultados para Syatematic derivation of monopole solutions
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International Biodeterioration & Biodegradation 64(2010)388 e 396
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The effects of ivermectin, a semi-synthetic drug widely used for treatment of livestock parasitic diseases, were observed on Culex quinquefasciatus larvae. Toxic effects and mortality evaluation were carried out after 5, 15, 30 and 60 minutes of exposure to 1, 5 or 10 ppm of ivermectin solutions. Observations were made 24 and 48 hours after the beginning of the experiment, and loss of mobility, progressive paralysis and high mortality of larvae were recorded. The observed effects of ivermectin on the mosquito larvae is probably correlated with chloride channel activation on cell membranes.
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Currently excessive fossil fuel consumption has become a serious problem. People are searching for new solutions of energy production and there are several options to obtain alternative sources of energy without further devastating the already destroyed environment. One of these solutions is growing microalgae, from which biodiesel can be obtained. The microalgae production is a growing business because of its many useful compounds. In order to collect these compounds microalgae must first be harvested and then dried. Nowadays the solutions used for drying use too much energy and therefore are too expensive and not sustainable. The goal of this project, one of the possible choices during the EPS@ISEP 2013 Spring, was to develop a solar microalgae dryer. The multinational team involved in its development was composed of five students, from distinct countries and fields of study, and was the responsible for designing a solar microalgae dryer prototype for the microalgae laboratory of the chemical engineering department at ISEP, suitable for future tests and incorporating control process (in order not to destroy the microalgae during the drying process). The solar microalgae dryer was built to work as a distiller that gets rid of the excess water from the microalgae suspension. This paper presents a possible solution for this problem, the steps to create the device to harvest the microalgae by drying them with the use of solar energy (also used as an energy source for the solar dryer control system), the technologies used to build the solar microalgae dryer, and the benefits it presents compared to current solutions. It also presents the device from the ethical and sustainable viewpoint. Such alternative to already existing methods is competitive as far as energy usage is concerned.
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Signal-to-interference ratio (SIR) performance of a multiband orthogonal frequency division multiplexing ultra-wideband system with residual timing offset is investigated. To do so, an exact mathematical derivation of the SIR of this system is derived. It becomes obvious that, unlike a cyclic prefixing based system, a zero padding based system is sensitive to residual timing offset.
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The evolution of the electrical grid into a smart grid, allowing user production, storage and exchange of energy, remote control of appliances, and in general optimizations over how the energy is managed and consumed, is also an evolution into a complex Information and Communication Technology (ICT) system. With the goal of promoting an integrated and interoperable smart grid, a number of organizations all over the world started uncoordinated standardization activities, which caused the emergence of a large number of incompatible architectures and standards. There are now new standardization activities which have the goal of organizing existing standards and produce best practices to choose the right approach(es) to be employed in specific smart grid designs. This paper follows the lead of NIST and ETSI/CEN/CENELEC approaches in trying to provide taxonomy of existing solutions; our contribution reviews and relates current ICT state-of-the-art, with the objective of forecasting future trends based on the orientation of current efforts and on relationships between them. The resulting taxonomy provides guidelines for further studies of the architectures, and highlights how the standards in the last mile of the smart grid are converging to common solutions to improve ICT infrastructure interoperability.
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A new man-tailored biomimetic sensor for Chlorpromazine host-guest interactions and potentiometric transduction is presented. The artificial host was imprinted within methacrylic acid, 2-vinyl pyridine and 2-acrylamido-2-methyl-1-propanesulfonic acid based polymers. Molecularly imprinted particles were dispersed in 2-nitrophenyloctyl ether and entrapped in a poly(vinyl chloride) matrix. Slopes and detection limits ranged 51–67 mV/decade and 0.46–3.9 μg/mL, respectively, in steady state conditions. Sensors were independent from the pH of test solutions within 2.0–5.5. Good selectivity was observed towards oxytetracycline, doxytetracycline, ciprofloxacin, enrofloxacin, nalidixic acid, sulfadiazine, trimethoprim, glycine, hydroxylamine, cysteine and creatinine. Analytical features in flowing media were evaluated on a double-channel manifold, with a carrier solution of 5.0 × 10−2 mol/L phosphate buffer. Near-Nernstian response was observed over the concentration range 1.0 × 10−4 to 1.0 × 10−2 mol/L. Average slopes were about 48 mV/decade. The sensors were successfully applied to field monitoring of CPZ in fish samples, offering the advantages of simplicity, accuracy, automation feasibility and applicability to complex samples.
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This paper presents the TEC4SEA research infrastructure created in Portugal to support research, development, and validation of marine technologies. It is a multidisciplinary open platform, capable of supporting research, development, and test of marine robotics, telecommunications, and sensing technologies for monitoring and operating in the ocean environment. Due to the installed research facilities and its privileged geographic location, it allows fast access to deep sea, and can support multidisciplinary research, enabling full validation and evaluation of technological solutions designed for the ocean environment. It is a vertically integrated infrastructure, in the sense that it possesses a set of skills and resources which range from pure conceptual research to field deployment missions, with strong industrial and logistic capacities in the middle tier of prototype production. TEC4SEA is open to the entire scientific and enterprise community, with a free access policy for researchers affiliated with the research units that ensure its maintenance and sustainability. The paper describes the infrastructure in detail, and discusses associated research programs, providing a strategic vision for deep sea research initiatives, within the context of both the Portuguese National Ocean Strategy and European Strategy frameworks.
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This paper addresses the challenging task of computing multiple roots of a system of nonlinear equations. A repulsion algorithm that invokes the Nelder-Mead (N-M) local search method and uses a penalty-type merit function based on the error function, known as 'erf', is presented. In the N-M algorithm context, different strategies are proposed to enhance the quality of the solutions and improve the overall efficiency. The main goal of this paper is to use a two-level factorial design of experiments to analyze the statistical significance of the observed differences in selected performance criteria produced when testing different strategies in the N-M based repulsion algorithm. The main goal of this paper is to use a two-level factorial design of experiments to analyze the statistical significance of the observed differences in selected performance criteria produced when testing different strategies in the N-M based repulsion algorithm.
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Dissertation to obtain the degree of Doctor of Philosophy in Electrical and Computer Engineering(Industrial Information Systems)
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Proceedings IGLC-18, July 2010, Technion, Haifa, Israel
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Proceedings IGLC-19, July 2011, Lima, Perú
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A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics
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This paper discusses the development of modular solutions for eco low-cost houses based on a pre-fabricated modular wall system environmentally sustainable, socioeconomically competitive and geared towards developing African nations with a housing deficit. The key point to the research of a modular wall solution is a structural layer complemented with local and materials made by non-specialized workforce. This wall also meets also hydrothermal acoustic and mechanical properties. Thus,the solution also offers good safety and interior comfort conditions to its users while maintaining the flexibility to expand the size of the house. Parameters as dimensions, materials and constructive processes of the existing housing stock were studied. Features such as the family size, typology, different uses, common materials, existing regulations, minimal living conditions, safety and comfort have also been considered to achieve the most efficient solution.
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Phenolic acids are aromatic secondary plant metabolites, widely spread throughout the plant kingdom. Due to their biological and pharmacological properties, they have been playing an important role in phytotherapy and consequently techniques for their separation and purification are in need. This thesis aims at exploring new sustainable separation processes based on ionic liquids (ILs) in the extraction of biologically active phenolic acids. For that purpose, three phenolic acids with similar chemical structures were selected: cinnamic acid, p-coumaric acid and caffeic acid. In the last years, it has been shown that ionic liquids-based aqueous biphasic systems (ABSs) are valid alternatives for the extraction, recovery and purification of biomolecules when compared to conventional ABS or extractions carried out with organic solvents. In particular, cholinium-based ILs represent a clear step towards a greener chemistry, while providing means for the implementation of efficient techniques for the separation and purification of biomolecules. In this work, ABSs were implemented using cholinium carboxylate ILs using either high charge density inorganic salt (K3PO4) or polyethylene glycol (PEG) to promote the phase separation of aqueous solutions containing three different phenolic acids. These systems allow for the evaluation of effect of chemical structure of the anion on the extraction efficiency. Only one imidazolium-based IL was used in order to establish the effect of the cation chemical structure. The selective extraction of one single acid was also researched. Overall, it was observed that phenolic acids display very complex behaviours in aqueous solutions, from dimerization to polymerization and also hetero-association are quite frequent phenomena, depending on the pH conditions. These phenomena greatly hinder the correct quantification of these acids in solution.
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One of the biggest challenges for humanity is global warming and consequently, climate changes. Even though there has been increasing public awareness and investments from numerous countries concerning renewable energies, fossil fuels are and will continue to be in the near future, the main source of energy. Carbon capture and storage (CCS) is believed to be a serious measure to mitigate CO2 concentration. CCS briefly consists of capturing CO2 from the atmosphere or stationary emission sources and transporting and storing it via mineral carbonation, in oceans or geological media. The latter is referred to as carbon capture and geological storage (CCGS) and is considered to be the most promising of all solutions. Generally it consists of a storage (e.g. depleted oil reservoirs and deep saline aquifers) and sealing (commonly termed caprock in the oil industry) formations. The present study concerns the injection of CO2 into deep aquifers and regardless injection conditions, temperature gradients between carbon dioxide and the storage formation are likely to occur. Should the CO2 temperature be lower than the storage formation, a contractive behaviour of the reservoir and caprock is expected. The latter can result in the opening of new paths or re-opening of fractures, favouring leakage and compromising the CCGS project. During CO2 injection, coupled thermo-hydro-mechanical phenomena occur, which due to their complexity, hamper the assessment of each relative influence. For this purpose, several analyses were carried out in order to evaluate their influences but focusing on the thermal contractive behaviour. It was finally concluded that depending on mechanical and thermal properties of the pair aquifer-seal, the sealing caprock can undergo significant decreases in effective stress.