719 research outputs found
Behavior of Reinforced Concrete Box Beam Strengthened with CFRP U-Wrap Strips Under Torsion
The present study focuses on the torsional strengthening behavior of reinforced
concrete (RC) box section beams that are widely used in bridges. Four RC box beams were
fabricated, and three of them were wrapped by carbon fiber-reinforced polymer (CFRP)
U-wrap strips with or without longitudinal strips. The different wrapping configuration,
cracking angle, failure pattern, and tensile strain of fibers were investigated and discussed
accordingly. The experimental results addressed that U-wrap strips strengthening also can
upgrade the ultimate torque of beams moderately. In particular, using U-wrap and longitudinal
strips to bond the box beams increased the torsional stiffness slightly. The same equation from
different codes for calculating RC specimens can accurately predict the ultimate strength of the
control beam, but the calculation of the fib model overestimated the torsional strengthening
improvement of the wrapped specimens. However, Ghobarah et al. assumed approximately
3000με of the average ultimate fiber strain in calculating the ultimate strength of the wrapped
box beams which shows in relatively appropriate agreement with testing results
Removal of Chromium (III) from Aqueous Solution by Coconut Husk and Rice Straw
Coconut husk fibre and rice straw were found to be able to remove significant amount of Cr (III) ions from aqueous solutions. Its removal is a function of pH
and concentration. The optimum pH range for maximum uptake is between 4 and 6 for both substrates. The adsorption capacity was found to be 0.55 and
0.30 millimole Cr (III) / g substrate for coconut husk and rice straw respectively. The adsorption kinetic studies show that the removal process follows a first order rate expression. The breakthrough curves and adsorption efficiency of various columns containing mixed media of coconut husk/rice straw, soil and sand have been obtained. The results demonstrate that these agricultural
residues could be used as barriers in a landfill to maximize immobilization of toxic metal ions such as Cr (III) in leachates
Asymmetric vibration of polar orthotropic annular circular plates of quadratically varying thickness with same boundary conditions
Abstract. In the present paper, asymmetric vibration of polar orthotropic annular circular plates of quadratically varying thickness resting on Winkler elastic foundation is studied by using boundary characteristic orthonormal polynomials in Rayleigh-Ritz method. Convergence of the results is tested and comparison is made with results already available in the existing literature. Numerical results for the first ten frequencies for various values of parameters describing width of annular plate, thickness profile, material orthotropy and foundation constant for all three possible combinations of clamped, simply supported and free edge conditions are shown and discussed. It is found that (a) higher elastic property in circumferential direction leads to higher stiffness against lateral vibration; (b) Lateral vibration characteristics of F -F plates is more sensitive towards parametric changes in material orthotropy and foundation stiffness than C-C and S-S plates; (c) Effect of quadratical thickness variation on fundamental frequency is more significant in cases of C-C and S-S plates than that of F -F plates. Thickness profile which is convex relative to plate center-line tends to result in higher stiffness of annular plates against lateral vibration than the one which is concave and (d) Fundamental mode of vibration of C-C and S-S plates is axisymmetrical while that of F -F plates is asymmetrical
NNT pseudoexon activation as a novel mechanism for disease in two siblings with familial glucocorticoid deficiency
CONTEXT:
Intronic DNA frequently encodes potential exonic sequences called pseudoexons. In recent years, mutations resulting in aberrant pseudoexon inclusion have been increasingly recognized to cause disease.
OBJECTIVES:
To find the genetic cause of familial glucocorticoid deficiency (FGD) in two siblings.
PATIENTS:
The proband and his affected sibling, from nonconsanguineous parents of East Asian and South African origin, were diagnosed with FGD at the ages of 21 and 8 months, respectively.
DESIGN:
Whole exome sequencing was performed on genomic DNA (gDNA) of the siblings. Variants in genes known to cause FGD were assessed for causality. Further analysis of gDNA and cDNA was performed by PCR/RT-PCR followed by automated Sanger sequencing.
RESULTS:
Whole exome sequencing identified a single, novel heterozygous variant (p.Arg71*) in nicotinamide nucleotide transhydrogenase (NNT) in both affected individuals. Follow-up cDNA analysis in the proband identified a 69-bp pseudoexon inclusion event, and Sanger sequencing of his gDNA identified a 4-bp duplication responsible for its activation. The variants segregated with the disease: p.Arg71* was inherited from the mother, the pseudoexon change was inherited from the father, and an unaffected sibling had inherited only the p.Arg71* variant.
CONCLUSIONS:
FGD in these siblings is caused by compound heterozygous mutations in NNT; one causing pseudoexon inclusion in combination with another leading to Arg71*. Discovery of this pseudoexon activation mutation highlights the importance of identifying sequence changes in introns by cDNA analysis. The clinical implications of these findings include: facilitation of antenatal genetic diagnosis, early institution of potentially lifesaving therapy, and the possibility of preventative or curative interventio
Properties of M31. II: A Cepheid disk sample derived from the first year of PS1 PAndromeda data
We present a sample of Cepheid variable stars towards M31 based on the first
year of regular M31 observations of the PS1 survey in the r_P1 and i_P1
filters. We describe the selection procedure for Cepheid variable stars from
the overall variable source sample and develop an automatic classification
scheme using Fourier decomposition and the location of the instability strip.
We find 1440 fundamental mode (classical \delta) Cep stars, 126 Cepheids in the
first overtone mode, and 147 belonging to the Population II types. 296 Cepheids
could not be assigned to one of these classes and 354 Cepheids were found in
other surveys. These 2009 Cepheids constitute the largest Cepheid sample in M31
known so far and the full catalog is presented in this paper. We briefly
describe the properties of our sample in its spatial distribution throughout
the M31 galaxy, in its age properties, and we derive an apparent
period-luminosity relation (PLR) in our two bands. The Population I Cepheids
nicely follow the dust pattern of the M31 disk, whereas the 147 Type II
Cepheids are distributed throughout the halo of M31. We outline the time
evolution of the star formation in the major ring found previously and find an
age gradient. A comparison of our PLR to previous results indicates a curvature
term in the PLR
SIP-based proactive and adaptive mobility management framework for heterogeneous networks
Abstract In this paper, we present and evaluate the performance of a mobility management system called the Proactive and Adaptive Handover (PAHO) system. PAHO is an application-level approach that uses SIP to manage client-initiated connection handoff across heterogeneous networks based on the IEEE 802.21 framework with designated user/configuration policy. Unlike conventional systems which make sub-optimal decision when managing connection handoff due to limited awareness of the relevant context for the application/service being delivered, PAHO defines proper interface to interact with the application as to determine when and to where the handoff and/or codec switching should take place in the event of network performance degradation. The results showed that using the PAHO approach on an audio/video conferencing session helps reducing the overall handover delay from 10.766 s (on non-PAHO system) down to at least 288 ms, and slowing down the degradation of MOS value throughout the entire experiment in the event of signal degradation as well as network congestion. It is also shown that load balancing among the access points (AP) could be achieved with an improved Information Server (IS). r 2007 Elsevier Ltd. All rights reserved
Search for the Lepton-Number-Violating Decay
A sensitive search for the lepton-number-violating decay has been performed using a sample of hyperons
produced in 800 GeV/ -Cu collisions. We obtain at 90% confidence, improving on the best
previous limit by four orders of magnitude.Comment: 9 pages, 5 figures, to be published in Phys. Rev. Let
Mixing in the Presence of Isosinglet Quarks
We analyse transitions in the framework of a minimal extension
of the Standard Model where either a or a isosinglet quark is
added to the standard quark spectrum. In the case of a isosinglet
quark, it is shown that there is a significant region of parameter space where
mixing is sufficiently enhanced to be observed at the next
round of experiments. On the contrary, in the case of a isosinglet
quark, it is pointed out that obtaining a substancial enhancement of mixing, while complying with the experimental constraints on rare
kaon decays, requires a contrived choice of parameters.Comment: 10 pages plus four figures. The figures are not included but are
available upon reques
Evidence for the Decay Sigma+ -> p mu+ mu-
We report the first evidence for the decay Sigma+ -> p mu+ mu- from data
taken by the HyperCP experiment(E871) at Fermilab. Based on three observed
events, the branching ratio is B(Sigma+ -> p,mu+,mu-) = [8.6 +6.6,-5.4(stat)
+/-5.5(syst)] x 10**-8. The narrow range of dimuon masses may indicate that the
decay proceeds via a neutral intermediate state, Sigma+ -> p P0, P0 -> mu+ mu-,
with a P0 mass of 214.3 +/- 0.5 MeV/c**2 and branching ratio B(Sigma+ -> p P0;
P0 -> mu+ mu-) = [3.1 +2.4,-1.(stat) +/-1.5(syst)] x 10**-8.Comment: As published in PR
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