1,202 research outputs found

    Duals of noncommutative supersymmetric U(1) gauge theory

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    Parent actions for component fields are utilized to derive the dual of supersymmetric U(1) gauge theory in 4 dimensions. Generalization of the Seiberg-Witten map to the component fields of noncommutative supersymmetric U(1) gauge theory is analyzed. Through this transformation we proposed parent actions for noncommutative supersymmetric U(1) gauge theory as generalization of the ordinary case.Duals of noncommutative supersymmetric U(1) gauge theory are obtained. Duality symmetry under the interchange of fields with duals accompanied by the replacement of the noncommutativity parameter \Theta_{\mu\nu} with \tilde{\Theta}_{\mu \nu} = \epsilon_{\mu\nu\rho\sigma}\Theta^{\rho\sigma} of the non--supersymmetric case is broken at the level of actions. We proposed a noncommutative parent action for the component fields which generates actions possessing this duality symmetry.Comment: Typos corrected. Version which will appear in JHE

    Evaluation of the biocompatibility of experimentally manufactured portland cement: an animal study

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    Objectives: The purpose of this study was to evaluate the biocompatibility of MTA and the experimentally manufactured portland cement (EMPC). Study design: Twenty one Sprague Dawley (SD) rats were allocated to testing of three groups. Group I and Group II included ProRoot MTA and the EMPC. The materials were mixed with distilled water and placed in polyethylene tubes. The tubes were implanted subcutaneously in the dorsal region of the animals. Group III served as control; the implanted polyethylene tubes remained empty. At 7, 14, and 28 days after the implantation, the animals were sacrificed and the implants were removed with the surrounding tissues. The specimens were prepared for histological examination to evaluate the inflammatory response. Results: No significant difference was found between tissue reactions against the tested materials (p>0.05). Also, control group showed similar results(p>0.05). Conclusions: Results suggest that the EMPC has the potential to be used in clinical conditions in which ProRoot MTA is indicated. MTA and the EMPC show comparable biocompatibility when evaluated in vivo. Although the results are supportive for the EMPC, more studies are required before the safe clinical use of the EMPC

    Climatic controls on biophysical interactions in the Black Sea under present day conditions and a potential future (A1B) climate scenario

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    A dynamical downscaling approach has been applied to investigate climatic controls on biophysical interactions and lower trophic level dynamics in the Black Sea. Simulations were performed under present day conditions (1980–1999) and a potential future (2080–2099) climate scenario, based on the Intergovernmental Panel for Climate Change A1B greenhouse gas emission scenario. Simulations project a 3.7 °C increase in SST, a 25% increase in the stability of the seasonal thermocline and a 37 day increase in the duration of seasonal stratification. Increased winter temperatures inhibited the formation of Cold Intermediate Layer (CIL) waters resulting in near complete erosion of the CIL, with implications for the ventilation of intermediate water masses and the subduction of riverine nutrients. A 4% increase in nitrate availability within the upper 30 m of the water column reflected an increase in the retention time of river water within the surface mixed-layer. Changes in thermohaline structure, combined with a 27% reduction in positive wind stress curl, forced a distinct change in the structure of the basin-scale circulation. The predominantly cyclonic circulation characteristic of contemporary conditions was reversed within the southern and eastern regions of the basin, where under A1B climatic conditions, anticyclonic circulation prevailed. The change in circulation structure significantly altered the horizontal advection and dispersion of high nutrient river waters originating on the NW self. Net primary production increased by 5% on average, with much spatial variability in the response, linked to advective processes. Phytoplankton biomass also increased by 5% and the higher nutrient environment of the future scenario caused a shift in species composition in favour of larger phytoplankton. No significant change in zooplankton biomass was projected. These results constitute one of many possible future scenarios for the Black Sea, being dependent on the modelling systems employed in addition to the choice of emission scenario. Our results emphasise in particular the sensitivity of dynamical downscaling studies to the regional wind forcing fields extracted from global models (these being typically model dependent). As atmospheric warming is projected with a high degree of confidence warming of the Black Sea upper layer, increased water column stability, and erosion of the CIL are believed to be robust results of this study

    Improvement of Thermal Processes for Using Residues from Bioethanol and Sugar Production in Brazil: Experiments and Proposed Optimization Measures

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    Within a national funded Brazilian-German cooperation project ASHES, the thermal utilization of bagasse and other residuals from the sugar processing industry was examined. The characterization of the ashes was also performed but it is not in the focus of this paper. To determine the relevant combustion parameters, tests were carried out in a laboratory-scale, fixed bed reactor (KLEAA) at KIT-ITC. Subsequently, Fraunhofer UMSICHT carried out tests in continuously operated combustion plants with different plant sizes of 30 kW, 100 kW, and 440 kW. All relevant compositions were analyzed by CUTEC. The primary objective was to gain knowledge regarding the combustion and emission behavior of the fuels. These findings were used to identify optimization potentials at various points and elaborate concepts for their improvement. In the next steps of the project, optimization of these concepts will be the focus. In cooperation with the Brazilian project partners, several of them should be implemented into practice after the project

    Honey Bees Inspired Optimization Method: The Bees Algorithm

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    Optimization algorithms are search methods where the goal is to find an optimal solution to a problem, in order to satisfy one or more objective functions, possibly subject to a set of constraints. Studies of social animals and social insects have resulted in a number of computational models of swarm intelligence. Within these swarms their collective behavior is usually very complex. The collective behavior of a swarm of social organisms emerges from the behaviors of the individuals of that swarm. Researchers have developed computational optimization methods based on biology such as Genetic Algorithms, Particle Swarm Optimization, and Ant Colony. The aim of this paper is to describe an optimization algorithm called the Bees Algorithm, inspired from the natural foraging behavior of honey bees, to find the optimal solution. The algorithm performs both an exploitative neighborhood search combined with random explorative search. In this paper, after an explanation of the natural foraging behavior of honey bees, the basic Bees Algorithm and its improved versions are described and are implemented in order to optimize several benchmark functions, and the results are compared with those obtained with different optimization algorithms. The results show that the Bees Algorithm offering some advantage over other optimization methods according to the nature of the problem

    Renewable energy policy in Turkey

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    Abstract: This study aims to explore the availability and potential of renewable energy sources in Turkey and discuss the government policies and economic aspects. Turkey is a country which has the highest hydropower and wind energy potential among European countries. Current energy policy of Turkey primarily aims to maximize geothermal, wind and hydropower potential of the country in next 15 years. In Several incentives were developed for electricity generation from renewable energy sources by the publication of Law No. 5346 in 2005. The most important ones are: ease of land acquisition and feed-in-tariffs which promises purchasing of electricity generated by legal entities with a price of 5-5.5 €c/kWh. Since Turkey is a European Union (EU) candidate its laws and regulations must be compatible with EU. As the legislation in EU member states is investigated it is apparent that Law No. 5346 should be restructured. This should include: (i) redetermination of feed-in-tariff amount according to type and capacity of renewable energy source, (ii) taking installed capacity into account instead of reservoir area for hydroelectric power plants as renewable energy source, (iii) making detailed Environmental Impact Assessment (EIA) report obligatory for renewable energy plants. The emphasis has been given on hydropower and wind energy. The renewable energy policy of Turkey has been compared with the advanced economies in Europe like Germany and Norwa

    PARAMETRICAL METHOD OF LOW-FREQUENCY HARMONICS SUPPRESSION IN RECTIFIER’S OUTPUT VOLTAGE UNDER SUPPLY VOLTAGE UNBALANCES (MATHEMATICAL MODEL, STUDY AND INDUSTRIAL APPLICATION)

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    This paper deals with using an original and pure electronic method for low-frequency harmonic suppression with wide industrial realization and application, in place of the usually heavy inductive, low-frequency harmonic filters. One of the main applications was made for small land power supply units of onboard complexesin ground-based air navigation when preflight ground check-service is made. The transport management at thousands of small provincial airports in the former country is still unfortunate. The same situation is in Northern and central Central Asia, Northern Caucasian and Trans-Caucasian Mountains, oriented to small civil and agricultural services airports, etc. Everywhere the phaseand line voltage amplitude unbalance can reach between 10-15% at the settlement’s power tiny transformer or generator and there are thousands and thousands of such local «airports» [1, 6]. This paperhas been editing by a native speaker, Ms. Rachel Alcorn — our sincere thanks

    A timing optimization method based on clock skew scheduling and partitioning in a parallel computing environment

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    Paper presented at the Midwest Symposium on Circuits and Systems, San Juan, Puerto Rico.This paper describes the implementation of a heuristic method to perform non-zero clock skew scheduling of digital VLSI circuits in a parallel computing environment. In the proposed method, circuit partitions that have low number of timing paths between partitions are formed. Clock skew scheduling is applied independently to each partition-sequentially or in parallel on a computing cluster-and results are iteratively merged. The scalability of the proposed method is superior compared to conventional non-zero clock skew scheduling techniques due to the reduction of analyzed circuit sizes (partition sizes) at each iteration step and the potential to parallelize the analyses of these partitions. It is demonstrated that after only the first iteration step of the proposed method, feasible clock schedules for 65% of the ISCAS'89 benchmark circuits are computed. For these circuits, average speedups of 2.1X and 2.6X are observed for sequential and parallel application of clock skew scheduling to partitions, respectively
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