366 research outputs found

    An Origami-Inspired Design of a Thermal Mixing Element Within a Concentrated Solar Power System

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    A Concentrated Solar Power on Demand (CSPonD) system heats a tank of molten salt with sunlight, storing the sun's energy thermally and generating electricity when needed using a heat exchanger. To prevent the heated salt from forming thermal gradients (reducing the heat exchanger's efficiency) or overheating (and becoming corrosive), a thermal mixing element mixes the heated salt both axially and radially. Since the mixing element can only move axially within the tank, it contains internal, radial channels to induce radial flow of the salt. These channels are constructed from tabbed wall-components, whose tabs seat into and extend past slots in the top-and bottom-plates of the mixing element. The top-and bottom-plates are constructed from multiple panels with overlapping slots, allowing the panels to form the plates when the tabs are inserted. This interlocking design allows majority of the mixing element to be rapidly manufactured at a low cost from sheet metal and simplifies transportation. In situ, the assembled components fasten together by bending the overextending tabs, minimizing the number of fasteners needed. Topics: Design, Concentrating solar powerMasdar Institute of Science and Technolog

    A MAGNETICALLY SUSPENDED, SPHERICAL PERMANENT MAGNETIC DIPOLE ACTUATOR

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    The attitude control system (ACS) of a spacecraft contains a minimum of three reaction wheels to rotate the spacecraft in 3 degrees of freedom (DoF), but typically contains additional reaction wheels for both redundancy and improved pointing accuracy. Each wheel rotates the spacecraft about its axis by imparting an equal-and-opposite torque when the spacecraft accelerates the wheel. Since space, weight, and power (SWaP) are a premium on a spacecraft, reaction spheres, which impart an equal-and-opposite torque about an arbitrary axis when the spacecraft accelerates the sphere about that axis, have been proposed to reduce the ACS down to a single device. While NASA first proposed reaction spheres over a half century ago, limitations with previous designs have kept the technology from commercialization. These designs can be generalized into two categories: asynchronous, induction-type actuators and synchronous actuators similar to DC and hysteresis motors. The induction-type designs are difficult to model and suffer from eddy current losses in the rotor while the synchronous designs often have rotors constructed from multiple magnets which presents fabrication, strength, and balance issues. To incorporate the best of both worlds, the mechanical simplicity of an induction motor with the efficiency and simple model of a brushless DC motor, a spherical permanent magnetic dipole rotor actuated by a stator of surrounding soils has been considered. This paper presents the modeling, design, and vertical suspension of a prototype permanent magnetic dipole reaction sphere depicted in Figure 1

    Large-Scale Gene Disruption in Magnaporthe oryzae Identifies MC69, a Secreted Protein Required for Infection by Monocot and Dicot Fungal Pathogens

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    To search for virulence effector genes of the rice blast fungus, Magnaporthe oryzae, we carried out a large-scale targeted disruption of genes for 78 putative secreted proteins that are expressed during the early stages of infection of M. oryzae. Disruption of the majority of genes did not affect growth, conidiation, or pathogenicity of M. oryzae. One exception was the gene MC69. The mc69 mutant showed a severe reduction in blast symptoms on rice and barley, indicating the importance of MC69 for pathogenicity of M. oryzae. The mc69 mutant did not exhibit changes in saprophytic growth and conidiation. Microscopic analysis of infection behavior in the mc69 mutant revealed that MC69 is dispensable for appressorium formation. However, mc69 mutant failed to develop invasive hyphae after appressorium formation in rice leaf sheath, indicating a critical role of MC69 in interaction with host plants. MC69 encodes a hypothetical 54 amino acids protein with a signal peptide. Live-cell imaging suggested that fluorescently labeled MC69 was not translocated into rice cytoplasm. Site-directed mutagenesis of two conserved cysteine residues (Cys36 and Cys46) in the mature MC69 impaired function of MC69 without affecting its secretion, suggesting the importance of the disulfide bond in MC69 pathogenicity function. Furthermore, deletion of the MC69 orthologous gene reduced pathogenicity of the cucumber anthracnose fungus Colletotrichum orbiculare on both cucumber and Nicotiana benthamiana leaves. We conclude that MC69 is a secreted pathogenicity protein commonly required for infection of two different plant pathogenic fungi, M. oryzae and C. orbiculare pathogenic on monocot and dicot plants, respectively

    Excavation of an early 17th-century glassmaking site at Glasshouse, Shinrone, Co. Offaly, Ireland

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    An archaeological research excavation was conducted in the area immediately surrounding an upstanding glassmaking furnace near Shinrone, Co. Offaly, Ireland. It dates to the early to mid 17th century and was built and operated by French Huguenots, probably de Hennezells (de Hennezel/Henzeys/Hensie) who had settled in this region as part of the Crown plantation of King’s County (now Co. Offaly). This furnace, which employed wood rather than coal as a fuel, is a very rare survival, with no other upstanding examples known in Ireland, Britain or the Lorraine region of France where the form probably originated

    Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

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    Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

    Search for heavy resonances decaying to two Higgs bosons in final states containing four b quarks

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    A search is presented for narrow heavy resonances X decaying into pairs of Higgs bosons (H) in proton-proton collisions collected by the CMS experiment at the LHC at root s = 8 TeV. The data correspond to an integrated luminosity of 19.7 fb(-1). The search considers HH resonances with masses between 1 and 3 TeV, having final states of two b quark pairs. Each Higgs boson is produced with large momentum, and the hadronization products of the pair of b quarks can usually be reconstructed as single large jets. The background from multijet and t (t) over bar events is significantly reduced by applying requirements related to the flavor of the jet, its mass, and its substructure. The signal would be identified as a peak on top of the dijet invariant mass spectrum of the remaining background events. No evidence is observed for such a signal. Upper limits obtained at 95 confidence level for the product of the production cross section and branching fraction sigma(gg -> X) B(X -> HH -> b (b) over barb (b) over bar) range from 10 to 1.5 fb for the mass of X from 1.15 to 2.0 TeV, significantly extending previous searches. For a warped extra dimension theory with amass scale Lambda(R) = 1 TeV, the data exclude radion scalar masses between 1.15 and 1.55 TeV

    Search for supersymmetry in events with one lepton and multiple jets in proton-proton collisions at root s=13 TeV

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    Measurement of the top quark mass using charged particles in pp collisions at root s=8 TeV

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    Measurement of the Splitting Function in &ITpp &ITand Pb-Pb Collisions at root&ITsNN&IT=5.02 TeV

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    Data from heavy ion collisions suggest that the evolution of a parton shower is modified by interactions with the color charges in the dense partonic medium created in these collisions, but it is not known where in the shower evolution the modifications occur. The momentum ratio of the two leading partons, resolved as subjets, provides information about the parton shower evolution. This substructure observable, known as the splitting function, reflects the process of a parton splitting into two other partons and has been measured for jets with transverse momentum between 140 and 500 GeV, in pp and PbPb collisions at a center-of-mass energy of 5.02 TeV per nucleon pair. In central PbPb collisions, the splitting function indicates a more unbalanced momentum ratio, compared to peripheral PbPb and pp collisions.. The measurements are compared to various predictions from event generators and analytical calculations.Peer reviewe
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