305 research outputs found

    Embankment on Vertical Drains - Pore Pressures During Construction

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    Excess pore pressures and consolidation settlements observed during the construction of a trial embankment placed on four different types of vertical drains are examined with the aim of evaluating: undrained pore pressure response, field coefficient of consolidation and drain performance

    Leaning Tower of Pisa — Updated Information

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    The paper is aimed at giving information on the present situation of the Leaning Tower of Pisa and on the activities undertaken for its safeguard by the International Committee appointed in May 1990 by the Italian Government. After a brief review of the subsoil conditions of the structural features and of the observed movements of the Tower, the activities undertaken by the Committee are also summarized

    Role of In-Situ Testing in Geotechnical Earthquake Engineering

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    The available in situ testing techniques of special relevance in Geotechnical Earthquake Engineering are subject to a synthetic review in the light of the general framework of soil stress-strain behavior. Especial attention is devoted to the recent innovations and current capabilities of in situ testing methods to assess the shear modulus G and damping ratio D. The determination of the undrained steady state shear strength via penetration and seismic tests is also discussed

    An analysis of pressuremeter holding tests

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    Cone penetration tests in a virtual calibration chamber

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    A virtual calibration chamber was built using a threedimensional model based on the discrete-element method. The chamber was then filled with a scaled granular equivalent of Ticino sand, the material properties of which were selected by curve-fitting triaxial tests. Cone penetration tests were then performed under different initial densities and isotropic stresses. Penetration resistance in the virtual calibration chamber was affected by the same cone/chamber size effect that affects physical calibration chambers and was corrected accordingly. The corrected cone resistance obtained from the virtual calibration chamber cone penetration tests shows good quantitative agreement with correlations that summarise previous physical results

    Radon-Nikodym derivatives of quantum operations

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    Given a completely positive (CP) map TT, there is a theorem of the Radon-Nikodym type [W.B. Arveson, Acta Math. {\bf 123}, 141 (1969); V.P. Belavkin and P. Staszewski, Rep. Math. Phys. {\bf 24}, 49 (1986)] that completely characterizes all CP maps SS such that T−ST-S is also a CP map. This theorem is reviewed, and several alternative formulations are given along the way. We then use the Radon-Nikodym formalism to study the structure of order intervals of quantum operations, as well as a certain one-to-one correspondence between CP maps and positive operators, already fruitfully exploited in many quantum information-theoretic treatments. We also comment on how the Radon-Nikodym theorem can be used to derive norm estimates for differences of CP maps in general, and of quantum operations in particular.Comment: 22 pages; final versio

    Nanoaperture fabrication via colloidal lithography for single molecule fluorescence analysis

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    In single molecule fluorescence studies, background emission from labeled substrates often restricts their concentrations to non-physiological nanomolar values. One approach to address this challenge is the use of zero-mode waveguides (ZMWs), nanoscale holes in a thin metal film that physically and optically confine the observation volume allowing much higher concentrations of fluorescent substrates. Standard fabrication of ZMWs utilizes slow and costly E-beam nano-lithography. Herein, ZMWs are made using a self-assembled mask of polystyrene microspheres, enabling fabrication of thousands of ZMWs in parallel without sophisticated equipment. Polystyrene 1 mu m dia. microbeads self-assemble on a glass slide into a hexagonal array, forming a mask for the deposition of metallic posts in the inter-bead interstices. The width of those interstices (and subsequent posts) is adjusted within 100-300 nm by partially fusing the beads at the polystyrene glass transition temperature. The beads are dissolved in toluene, aluminum or gold cladding is deposited around the posts, and those are dissolved, leaving behind an array ZMWs. Parameter optimization and the performance of the ZMWs are presented. By using colloidal self-assembly, typical laboratories can make use of sub-wavelength ZMW technology avoiding the availability and expense of sophisticated clean-room environments and equipment

    Entangling operations and their implementation using a small amount of entanglement

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    We study when a physical operation can produce entanglement between two systems initially disentangled. The formalism we develop allows to show that one can perform certain non-local operations with unit probability by performing local measurement on states that are weakly entangled.Comment: 4 pages, no figure
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