6,944 research outputs found

    Eksplorasi Air Tanah di Pandaan

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    This geoelectricity survey was conducted to get an idea of the distribution of resistivity (rock resistivity) either vertically or laterally, especially the alleged distribution of layers of rock can serve as carriers of water layer or aquifer. The results of this survey are expected to provide data to the PT Sampoerna, about the possibilities of layout, the existence and depth of carrier layers of water that can be used to meet the supply water for the needs of the Integrated Education Trainning Center. The results of the geoelectricity measurements were generally cannot reach the target depth to be surveyed, where, from the 10 points of sounding wich were conducted, only 3 points could penetrate the >100 m depths in VES VES-2,-6,-7 and VES VES-8. This were likely due to the resistivity characteristics between rock layers which entirely were the product of volcanic activity in the form of breksi, breksi Tuff, lava and tuff were not so different that less could be detected properly. The value of soil or rocks doty resistivity ranged from 0.5 to 868 Wm, volcanic breksi ranged from 1156 to 1944 Wm, volcanic breksi and aquifer I (shallow) ranged from 600 to 770 Wm, tuf ranged from 16 to 80 Wm, breksi Tuff and aquifer II (deep) ranged from 126 to 226 Wm. The possibility of the aquifer I (shallow) spreads were throughout the entire VES with the top depth ranged from 1.74 to 15.66 m. The base depth ranged from 14 to 28.59 m. The aquifer I thickness ranged from 8.37 to 16.36 m. The possibility of the aquifer II (deep) spreads were throughout the entire VES-2, VES-5, VES-6, and VES-7 with the top depth ranged from 17.16 to 72.32 m. The base depth ranged from 80 to 149.08 m. The aquifer I thickness ranged from 22,85 to 131,92 m. For the purposes of the water supply, it is recommended to perform the drilling around the VES-5, VES-6, VES-7 and VES-8 or by the VES-2 because in those areas have the potential of 2 aquifer layers or a thick aquifer layer

    Quasi-Local Energy Flux of Spacetime Perturbation

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    A general expression for quasi-local energy flux for spacetime perturbation is derived from covariant Hamiltonian formulation using functional differentiability and symplectic structure invariance, which is independent of the choice of the canonical variables and the possible boundary terms one initially puts into the Lagrangian in the diffeomorphism invariant theories. The energy flux expression depends on a displacement vector field and the 2-surface under consideration. We apply and test the expression in Vaidya spacetime. At null infinity the expression leads to the Bondi type energy flux obtained by Lindquist, Schwartz and Misner. On dynamical horizons with a particular choice of the displacement vector, it gives the area balance law obtained by Ashtekar and Krishnan.Comment: 8 pages, added appendix, version to appear in Phys. Rev.

    A Proposal for a Multi-Drive Heterogeneous Modular Pipe- Inspection Micro-Robot

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    This paper presents the architecture used to develop a micro-robot for narrow pipes inspection. Both the electromechanical design and the control scheme will be described. In pipe environments it is very useful to have a method to retrieve information of the state of the inside part of the pipes in order to detect damages, breaks and holes. Due to the di_erent types of pipes that exists, a modular approach with di_erent types of modules has been chosen in order to be able to adapt to the shape of the pipe and to chose the most appropriate gait. The micro-robot has been designed for narrow pipes, a _eld in which there are not many prototypes. The robot incorporates a camera module for visual inspection and several drive modules for locomotion and turn (helicoidal, inchworm, two degrees of freedom rotation). The control scheme is based on semi-distributed behavior control and is also described. A simulation environment is also presented for prototypes testing

    Allogeneic morphogenetic protein vs. recombinant human bone morphogenetic protein-2 in lumbar interbody fusion procedures: a radiographic and economic analysis

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    BACKGROUND: Since the introduction of rhBMP-2 (Infuse®) in 2002, surgeons have had an alternative substitute to autograft and its related donor site morbidity. Recently, the prevalence of reported adverse events and complications related to the use of rhBMP-2 has raised many ethical and legal concerns for surgeons. Additionally, the cost and decreasing reimbursement landscape of rhBMP-2 use have required identification of a viable alternative. Osteo allogeneic morphogenetic protein (OsteoAMP®) is a commercially available allograft-derived growth factor rich in osteoinductive, angiogenic, and mitogenic proteins. This study compares the radiographic fusion outcomes between rhBMP-2 and OsteoAMP allogeneic morphogenetic protein in lumbar interbody fusion spine procedures. METHODS: Three hundred twenty-one (321) patients from three centers underwent a transforaminal lumbar interbody fusion (TLIF) or lateral lumbar interbody fusion (LLIF) procedure and were assessed by an independent radiologist for fusion and radiographically evident complications. The independent radiologist was blinded to the intervention, product, and surgeon information. Two hundred and twenty-six (226) patients received OsteoAMP with autologous local bone, while ninety-five (95) patients received Infuse with autologous local bone. Patients underwent radiographs (x-ray and/or CT) at standard postoperative follow-up intervals of approximately 1, 3, 6, 12, and 18 months. Fusion was defined as radiographic evidence of bridging across endplates, or bridging from endplates to interspace disc plugs. Osteobiologic surgical supply costs were also analyzed to ascertain cost differences between OsteoAMP and rhBMP-2. RESULTS: OsteoAMP produced higher rates of fusion at 6, 12, and 18 months (p ≤ 0.01). The time required for OsteoAMP to achieve fusion was approximately 40% less than rhBMP-2 with approximately 70% fewer complications. Osteobiologic supply costs were 80.5% lower for OsteoAMP patients (73.7% lower per level) than for rhBMP-2. CONCLUSIONS: Results of this study indicate that OsteoAMP is a viable alternative to rhBMP-2 both clinically and economically when used in TLIF and LLIF spine procedures

    Electronic Structure of Electron-doped Sm1.86Ce0.14CuO4: Strong `Pseudo-Gap' Effects, Nodeless Gap and Signatures of Short Range Order

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    Angle resolved photoemission (ARPES) data from the electron doped cuprate superconductor Sm1.86_{1.86}Ce0.14_{0.14}CuO4_4 shows a much stronger pseudo-gap or "hot-spot" effect than that observed in other optimally doped nn-type cuprates. Importantly, these effects are strong enough to drive the zone-diagonal states below the chemical potential, implying that d-wave superconductivity in this compound would be of a novel "nodeless" gap variety. The gross features of the Fermi surface topology and low energy electronic structure are found to be well described by reconstruction of bands by a 2×2\sqrt{2}\times\sqrt{2} order. Comparison of the ARPES and optical data from the samesame sample shows that the pseudo-gap energy observed in optical data is consistent with the inter-band transition energy of the model, allowing us to have a unified picture of pseudo-gap effects. However, the high energy electronic structure is found to be inconsistent with such a scenario. We show that a number of these model inconsistencies can be resolved by considering a short range ordering or inhomogeneous state.Comment: 5 pages, 4 figure

    Properties of the symplectic structure of General Relativity for spatially bounded spacetime regions

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    We continue a previous analysis of the covariant Hamiltonian symplectic structure of General Relativity for spatially bounded regions of spacetime. To allow for near complete generality, the Hamiltonian is formulated using any fixed hypersurface, with a boundary given by a closed spacelike 2-surface. A main result is that we obtain Hamiltonians associated to Dirichlet and Neumann boundary conditions on the gravitational field coupled to matter sources, in particular a Klein-Gordon field, an electromagnetic field, and a set of Yang-Mills-Higgs fields. The Hamiltonians are given by a covariant form of the Arnowitt-Deser-Misner Hamiltonian modified by a surface integral term that depends on the particular boundary conditions. The general form of this surface integral involves an underlying ``energy-momentum'' vector in the spacetime tangent space at the spatial boundary 2-surface. We give examples of the resulting Dirichlet and Neumann vectors for topologically spherical 2-surfaces in Minkowski spacetime, spherically symmetric spacetimes, and stationary axisymmetric spacetimes. Moreover, we show the relation between these vectors and the ADM energy-momentum vector for a 2-surface taken in a limit to be spatial infinity in asymptotically flat spacetimes. We also discuss the geometrical properties of the Dirichlet and Neumann vectors and obtain several striking results relating these vectors to the mean curvature and normal curvature connection of the 2-surface. Most significantly, the part of the Dirichlet vector normal to the 2-surface depends only the spacetime metric at this surface and thereby defines a geometrical normal vector field on the 2-surface. Properties and examples of this normal vector are discussed.Comment: 46 pages; minor errata corrected in Eqs. (3.15), (3.24), (4.37) and in discussion of examples in sections IV B,
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