2,234 research outputs found

    A Four Slot Dual Feed and Dual Band Reconfigurable Antenna for Fixed Satellite Service Applications

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    A dual feed and dual-band reconfigurable antenna is designed, analyzed, and prototyped in this work for fixed satellite service communication applications. The designed model occupies the compact dimension of 24X21X1.2 mm on FR4 substrate and provides an input impedance of 50 ohms at both ports. The proposed model offers additional circular polarization characteristics at both the resonating bands. The PIN diode-based switching conditions, and the frequency reconfigurability analysis in both simulation and measurement are almost match. The combination of dual-band resonance, frequency reconfigurable nature, and compact dimension makes this model an attractive candidate in the specified field with considerable gain (8.5 dB) and efficiency (80%)

    Bottleneck Routing Games with Low Price of Anarchy

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    We study {\em bottleneck routing games} where the social cost is determined by the worst congestion on any edge in the network. In the literature, bottleneck games assume player utility costs determined by the worst congested edge in their paths. However, the Nash equilibria of such games are inefficient since the price of anarchy can be very high and proportional to the size of the network. In order to obtain smaller price of anarchy we introduce {\em exponential bottleneck games} where the utility costs of the players are exponential functions of their congestions. We find that exponential bottleneck games are very efficient and give a poly-log bound on the price of anarchy: O(logLlogE)O(\log L \cdot \log |E|), where LL is the largest path length in the players' strategy sets and EE is the set of edges in the graph. By adjusting the exponential utility costs with a logarithm we obtain games whose player costs are almost identical to those in regular bottleneck games, and at the same time have the good price of anarchy of exponential games.Comment: 12 page

    Aluminothermic process for the preparation of Ferromolybdenum and Ferrovanadium

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    The paper presents laboratory development of processes involving aluminothermic reduction, in open reactors, for the preparation of ferromolybdenum and ferrovanadium starting from indigenously available resources. The coverage incorporates chemical processing that has been developed for treating the starting resources such as low grade sulphide concentrate/molybdenum scrap/molybdenum laden solution for molybdenum and vanadium bearing slag or vanadium sludge for vanadium to prepare suitable intermed-iates. These essentially constitute raw materials develop-ed as alternative to the conventional ores for the two ferroalloys

    Uji Aktifitas Ekstrak Daun Sicerek (Clausena Excavata Burm. F) terhadap Candida Albicans

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    Lebih dari 50%-80% infeksi jamur berada di rongga mulut. Infeksi jamur pada rongga mulut yang disebut dengan kandidiasis disebabkan oleh Candida albicans. Pengobatan kandidiasis biasanya dengan penggunaan obat antijamur dimana kandungannya dari bahan sintesis. Penggunaan bahan sintesis tidak sepenuhnya aman karena menimbulkan berbagai efek samping, dengan demikian untuk meminimalkan efek samping dalam pengobatan dapat digunakan obat dari bahan alami. Salah satu obat yang seringdigunakan oleh masyarakat Sumatra Barat yaitu daun sicerek (Clausena Excavata Burm F). Daun sicerek (Clausena Excavata Burm F) mengandung senyawa aktif alkaloid dan flavonoid yang dapat digunakan sebagai antijamur. Jenis penelitian ini adalah penelitian eksperimental laboratorium secara in vitro untuk mengetahui aktivitas antijamur ekstrak daun sicerek (Clausena Excavata Burm F) terhadap jamur Candida albicans. Analisa statistik menggunakan uji Anova dengan nilai p= 0,00

    A Time-Space Tradeoff for Triangulations of Points in the Plane

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    In this paper, we consider time-space trade-offs for reporting a triangulation of points in the plane. The goal is to minimize the amount of working space while keeping the total running time small. We present the first multi-pass algorithm on the problem that returns the edges of a triangulation with their adjacency information. This even improves the previously best known random-access algorithm

    Operative planning in Thoracic Surgery: A pilot study comparing imaging techniques and 3D printing.

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    BACKGROUND: Careful preoperative planning in thoracic surgery is essential for positive outcomes especially in video assisted thoracic surgery (VATS) where palpation and 3-dimensional imaging is restricted. The objective of this study was to evaluate the ability of different imaging techniques such as Computerized Tomography (CT) scanning, maximal intensity projection (MIP) imaging, 3-dimensional (3D) reconstruction as well as 3D printing, to define the anatomy of the hilar structures prior to anatomical lung resection. METHODS: All patients undergoing elective lung resections by VATS for cancer under a single surgeon were identified over a three-month period. A single surgeon was asked to record the number of pulmonary artery branches supplying the lobe to be resected using the preoperative CT scan, MIP images and 3D reconstructed CT images. 3 patients had their lung hilum printed. These were then compared to the intraoperative findings. RESULTS: 16 patients had their preoperative imaging analyzed. A further 3 patients had their lung hilum 3D printed. Although not statistically significant, the 3D prints of the hilum were found to be the most accurate measurement with a correlation of 0.92. CT, 3D reconstructed CT and MIP images tended to under recognize the number of arterial branches and therefore scored between 0.26 and 0.39 in terms of absolute agreement with the number of arteries found at operation. CONCLUSIONS: 3D printing in the planning of thoracic surgery may suggest a benefit over contemporary available imaging modalities and the use of 3D printing in practicing operations is being established

    Large collective Lamb shift of two distant superconducting artificial atoms

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    Virtual photons can mediate interaction between atoms, resulting in an energy shift known as a collective Lamb shift. Observing the collective Lamb shift is challenging, since it can be obscured by radiative decay and direct atom-atom interactions. Here, we place two superconducting qubits in a transmission line terminated by a mirror, which suppresses decay. We measure a collective Lamb shift reaching 0.8% of the qubit transition frequency and exceeding the transition linewidth. We also show that the qubits can interact via the transmission line even if one of them does not decay into it.Comment: 7+5 pages, 4+2 figure
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