7,949 research outputs found

    Nature-inspired Cuckoo Search Algorithm for Side Lobe Suppression in a Symmetric Linear Antenna Array

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    In this paper, we proposed a newly modified cuckoo search (MCS) algorithm integrated with the Roulette wheel selection operator and the inertia weight controlling the search ability towards synthesizing symmetric linear array geometry with minimum side lobe level (SLL) and/or nulls control. The basic cuckoo search (CS) algorithm is primarily based on the natural obligate brood parasitic behavior of some cuckoo species in combination with the Levy flight behavior of some birds and fruit flies. The CS metaheuristic approach is straightforward and capable of solving effectively general N-dimensional, linear and nonlinear optimization problems. The array geometry synthesis is first formulated as an optimization problem with the goal of SLL suppression and/or null prescribed placement in certain directions, and then solved by the newly MCS algorithm for the optimum element or isotropic radiator locations in the azimuth-plane or xy-plane. The study also focuses on the four internal parameters of MCS algorithm specifically on their implicit effects in the array synthesis. The optimal inter-element spacing solutions obtained by the MCS-optimizer are validated through comparisons with the standard CS-optimizer and the conventional array within the uniform and the Dolph-Chebyshev envelope patterns using MATLABTM. Finally, we also compared the fine-tuned MCS algorithm with two popular evolutionary algorithm (EA) techniques include particle swarm optimization (PSO) and genetic algorithms (GA)

    Selection Of A Filler For Tablets Manufactured With Direct Compression Method Containing Dry Ginger Extract

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    The preliminary studies of physico-chemical and pharmaco-technological properties of the dry extract of ginger have determined the need for introduction of different groups of excipients for developing a solid dosage form for the treatment of type II diabetes mellitus.Aim. To choose the rational filler in the composition of tablets with ginger obtained by direct compression.Materials and methods. The study object was the dry extract of ginger (DEG) (producer “Megaprom”, Dnepr,Ukraine) and modern excipients for the production of tablets by direct compression: GalenIQ 721 (BENEO-Palatinit Gmb), Flowlac 100 (Meggle Co.), Tablettose 80 (Meggle Co.), Farmaxx (Merck), Microcelac 100 (Meggle Co.), Vivapur 112 and 102 (JRS Pharm), Prosolv HD 90, Prosolv SMCC 50 (JRS Pharm) manufactured in Germany. Pharmaco-technological and physico-chemical properties of the samples were studied according to conventional methods of the State Pharmacopoeia of Ukraine.Results and discussion. According to the results of the crystallographic analysis, the ability to the moisture absorption, resistance to crushing, disintegration time, fluidity indicators, angle of repose and bulk volume the effect of modern excipients on physicochemical and pharmaco-technological properties of the dry extract of ginger has been studied.Conclusions. According to the results of microscopic analysis, it has been found, that the rational fillers are GalenIQ 721, Prosolv HD 90, Prosolv SMCC 50, Vivapur 102 and Vivapur 112, as they provide a uniform system and the necessary resistance to destruction. The study of the kinetics of the moisture absorption has shown that addition of the fillers significantly reduces the increase in moisture compared to the dry extract. The mixture with GalenIQ 721 has the lowest parameters of moisture absorption at a relative air humidity of 45 %, 75 % and 100 %. In accordance with the results of the pharmaco-technological studies, it has been found that addition of GalenIQ 721 leads to improved flowability, disintegration, settling qualities; it indicates the feasibility of its inclusion into the composition of the solid dosage form

    Coherent current states in mesoscopic four-terminal Josephson junction

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    A theory is offered for the ballistic 4-terminal Josephson junction. The studied system consists of a mesoscopic two-dimensional normal rectangular layer which is attached in each side to the bulk superconducting banks (terminals). The relation between the currents through the different terminals, which is valid for arbitrary temperatures and junction sizes, is obtained. The nonlocal coupling of the supercurrents leads to a new effect, specific for the mesoscopic weak link between two superconducting rings; an applied magnetic flux through one of the rings produces a magnetic flux in the other ring even in the absence of an external flux through the other one. The phase dependent distributions of the local density of Andreev states, of the supercurrents and of the induced order parameter are obtained. The "interference pattern" for the anomalous average inside the two dimensional region can be regulated by the applied magnetic fluxes or the transport currents. For some values of the phase differences between the terminals, the current vortex state and the two dimensional phase slip center are appeared.Comment: 17 pages in Latex and 6 ps Figures. Will be published in Low Temp.Phy

    U-duality in three and four dimensions

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    Using generalised geometry we study the action of U-duality acting in three and four dimensions on the bosonic fields of eleven dimensional supergravity. We compare the U-duality symmetry with the T-duality symmetry of double field theory and see how the SL(2)SL(3)SL(2)\otimes SL(3) and SL(5) U-duality groups reduce to the SO(2,2) and SO(3,3) T-duality symmetry groups of the type IIA theory. As examples we dualise M2-branes, both black and extreme. We find that uncharged black M2-branes become charged under U-duality, generalising the Harrison transformation, while extreme M2-branes will become new extreme M2-branes. The resulting tension and charges are quantised appropriately if we use the discrete U-duality group Ed(Z)E_d(Z).Comment: v1: 35 pages; v2: minor corrections in section 4.1.2, many references added; v3: further discussion added on the conformal factor of the generalised metric in section 2 and on the Wick-rotation used to construct examples in section

    IL-2: Fine-tuning the Germinal Center Reaction

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    T follicular cells help B cells to drive germinal center formation. In this issue of Immunity, Ballesteros-Tato et al. (2012) demonstrate that high amounts of interleukin-2 inhibit production of this critical T effector subset

    The Relationship of Creativity Domains with Personality Traits and Academic Environment in Higher Education

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    Creativity assessment is the cornerstone of effective creativity development in higher education It is one of the main topics in creativity research as it is one of the most difficult skill to measure in any of the 21 st century skills We argue that in additions to the big five creativity in higher education is related to the environment and that more research is needed to understand this relations Therefore this study aimed to investigate this relations specifically creativity domain with personality traits and the academic environment Measures for these constructs were administered to 103 Malaysian undergraduate students In order to examine the nature of the relations between creative personality and other constructs we used Structural Equation Modeling The results indicate that the model is valid and reliable for assessing the creative person of higher education students This study showed that both personality traits and academic environment are important to assess the creative personalit

    Modified-nano-adsorbents for nitrate efficient removal: a review

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    Excessive nitrate discharge into the aquatic environment from human activities is the main contributor to groundwater and surface water contamination. Its toxicity in water is a serious concern as it gives huge impacts on aquatic life since it damages the ecosystem and water sources around the globe. Recently, the development of nanomaterials as nano-adsorbent makes adsorption the most attractive solution among them. Nano-adsorbents pose high efficiency to remove pollutants from aqueous media. The exclusive chemical and structural properties of the developed nano-adsorbents are the determinative effects of nitrate adsorption performance. In this mini review, the state-of-the-art development of nano-adsorbents and nano-adsorbents-modified membranes for nitrate from water is discussed, and some challenges faced in this field are also highlighted

    Textile Diamond Dipole and Artificial Magnetic Conductor Performance under Bending, Wetness and Specific Absorption Rate Measurements

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    Textile diamond dipole and Artificial Magnetic Conductor (AMC) have been proposed and tested under wearable and body centric measurements. The proposed antenna and AMC sheet are entirely made of textiles for both the substrate and conducting parts, thus making it suitable for wearable communications. Directive radiation patterns with high gain are obtained with the proposed AMC sheet, hence minimizing the radiation towards the human body. In this study, wearable and body centric measurements are investigated which include bending, wetness and Specific Absorption Rate (SAR). Bending is found not to give significant effect to the antenna and AMC performance, as opposed to wetness that yields severe performance distortion. However, the original performance is retrieved once the antenna and AMC dried. Moreover, notable SAR reduction is achieved with the introduction of the AMC sheet, which is appropriate to reduce the radiation that penetrates into human flesh
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