1,298 research outputs found
Preliminary Study of S-Wave Velocity and Unconfined Compressive Strength of Cement- Palf Stabilised Kaolin
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
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
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.
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
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 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
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
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
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 ) 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
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
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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