1,298 research outputs found

    Preliminary Study of S-Wave Velocity and Unconfined Compressive Strength of Cement- Palf Stabilised Kaolin

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    Clays are notoriously well known for giving rise to myriad problems and difficulties inconstruction due to excessive settlement and limited strength. Hence, there is a need to pretreatthe soils prior to construction, such as improving the engineering properties via thestabilisation technique, before additional load can be applied on it. In soil stabilisation,cement is commonly used as a stabilizing agent, to simultaneously increase the strength andstiffness of the originally weak, soft material. However cement is relatively expensive andpotentially harmful to the environment when admixed with soils. The need for alternativestabilizing agents which could reduce the use of cement is therefore apparent. In this study,natural fibres were retrieved from pineapple leaves, an agricultural waste product typical ofJohor. Next pre-determined quantities of pineapple leaf fibres (PALF) were added to anartificial clay, kaolin, together with cement. The mixture was formed into specimens of 38mm diameter and 76 mm high, cured in dry condition before being subjected to the s-wavevelocity and unconfined strength measurements. A range of curing period was introduced toexamine the effect of time on the performance of the stabilised specimens too. It was foundthat the fibres function as a form of reinforcement to the soil. Also, the test data revealed thatPALF alone makes negligible contribution to the improved properties, where cement isnecessary to act as a binder to strengthen the soil matrix. Nevertheless the potential of usingPALF as an additive to cement in soft soil stabilisation is promising, though further work isnecessary to better understand the stabilised material and its long term performance

    Managing peer relationships online - Investigating the use of Facebook by juvenile delinquents and youths-at-risk

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    10.1016/j.chb.2012.04.025Computers in Human Behavior2918-15CHBE

    Pharmaceutical Properties of Nanoparticulate Formulation Composed of TPGS and PLGA for Controlled Delivery of Anticancer Drug

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    A suitable management of the pharmaceutical property is needed and helpful to design a desired nanoparticulate delivery system, which includes the carrier nature, particle size and size distribution, morphology, surfactant stabiliser according to the technique applied, drug-loading ratio and encapsulation efficiency, surface property, etc. All will influence the in vitro release, in vivo behaviour and tissue distribution of administered particulate drug loaded nanoparticles. The main purpose of the present work was to determine the effect of drug loading ratio when employing TPGS as surfactant stabiliser and/or matrix material to improve the nanoparticulate formulation. The model drug employed was paclitaxel.Singapore-MIT Alliance (SMA

    Implementation of bowel ultrasound practice for the diagnosis and management of necrotising enterocolitis.

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    Necrotising enterocolitis (NEC) is a serious inflammatory bowel disease of prematurity with potentially devastating complications and remains a leading cause of morbidity and mortality among premature infants. In recent years, there has been accumulating data regarding benefits of using bowel ultrasound (BUS) in the diagnosis and management of NEC. Despite this, adoption of robust BUS programmes into clinical practice has been slow. As BUS is a relatively new technique, many barriers to implementation exist, namely lack of education and training for sonographers and radiologists, low case volume and unfamiliarity by clinicians regarding how to use the information provided. The aim of this manuscript is to provide a framework and a roadmap for units to implement BUS in day-to-day practice for NEC diagnosis and management

    Weak in Space, Log in Time Improvement of the Lady{\v{z}}enskaja-Prodi-Serrin Criteria

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    In this article we present a Lady{\v{z}}enskaja-Prodi-Serrin Criteria for regularity of solutions for the Navier-Stokes equation in three dimensions which incorporates weak LpL^p norms in the space variables and log improvement in the time variable.Comment: 14 pages, to appea

    Charged black holes in generalized dilaton-axion gravity

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    We study generic Einstein-Maxwell-Kalb-Ramond-dilaton actions, and derive conditions under which they give rise to static, spherically symmetric black hole solutions. We obtain new asymptotically flat and non-flat black hole solutions which are in general electrically and magnetically charged. They have positive definite and finite quasi-local masses. Existing non-rotating black hole solutions (including those appearing in low energy string theory) are recovered in special limits.Comment: Replaced with revised version, 33 pages, No figure

    RS1, Higher Derivatives and Stability

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    We demonstrate the classical stability of the weak/Planck hierarchy within the Randall-Sundrum scenario, incorporating the Goldberger-Wise mechanism and higher-derivative interactions in a systematic perturbative expansion. Such higher-derivative interactions are expected if the RS model is the low-energy description of some more fundamental theory. Generically, higher derivatives lead to ill-defined singularities in the vicinity of effective field theory branes. These are carefully treated by the methods of classical renormalization.Comment: 30 page

    Thermodynamics of a Kerr Newman de Sitter Black Hole

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    We compute the conserved quantities of the four-dimensional Kerr-Newman-dS (KNdS) black hole through the use of the counterterm renormalization method, and obtain a generalized Smarr formula for the mass as a function of the entropy, the angular momentum and the electric charge. The first law of thermodynamics associated to the cosmological horizon of KNdS is also investigated. Using the minimal number of intrinsic boundary counterterms, we consider the quasilocal thermodynamics of asymptotic de Sitter Reissner-Nordstrom black hole, and find that the temperature is equal to the product of the surface gravity (divided by 2π2\pi) and the Tolman redshift factor. We also perform a quasilocal stability analysis by computing the determinant of Hessian matrix of the energy with respect to its thermodynamic variables in both the canonical and the grand-canonical ensembles and obtain a complete set of phase diagrams. We then turn to the quasilocal thermodynamics of four-dimensional Kerr-Newman-de Sitter black hole for virtually all possible values of the mass, the rotation and the charge parameters that leave the quasilocal boundary inside the cosmological event horizon, and perform a quasilocal stability analysis of KNdS black hole.Comment: REVTEX4, 12 pages, 12 figures, references added and some points in Sec II have been clarified, version to appear in Can. J. Phy

    Geodesic motions in extraordinary string geometry

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    The geodesic properties of the extraordinary vacuum string solution in (4+1) dimensions are analyzed by using Hamilton-Jacobi method. The geodesic motions show distinct properties from those of the static one. Especially, any freely falling particle can not arrive at the horizon or singularity. There exist stable null circular orbits and bouncing timelike and null geodesics. To get into the horizon {or singularity}, a particle need to follow a non-geodesic trajectory. We also analyze the orbit precession to show that the precession angle has distinct features for each geometry such as naked singularity, black string, and wormhole.Comment: 15 pages, 11 figure

    Greybody Factors of Charged Dilaton Black Holes in 2 + 1 Dimensions

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    We have studied scalar perturbations of charged dilaton black holes in 2+1 dimensions. The black hole considered here is a solution to the low-energy string theory in 2+1 dimensions. The exact decay rates and the grey body factors for the massless minimally coupled scalar is computed for both the charged and the uncharged dilaton black holes. The charged and the uncharged black hole show similar behavior for grey body factors, reflection coefficients and decay rates.Comment: The equation for the potential and figure:1 are changed. The changes does not effect the result
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