99 research outputs found
The Relation between Self-Citation and Impact Factor in Medical Science Open Access Journals in ISI & DOAJ Databases
Citation is one of the important elements in scientific literature which has a significant role in information production and generation. Self-citation is a part of citation behavior. Relying on their articles, journals can change the number of citations and consequently the level of journal impact factor. This research aims at investigating the relation between self-citation and impact factor in the open access journals indexed in ISI and DOAJ in medical science in 2007-08. In this research, indexes such as the relation between self-citation of journal and impact factor and the effect of self-citation rate of the journal in open access performance are investigated. Research method is an analytical method conducted by using citation analysis technique. SPSS statistical software was used to examine and analyze the data and its inferential analysis methods such as Pierson Factor were used as well. Statistical society includes 168 journals. The results showed a self-citation rate of 28% for the journal. The findings indicate that there is a significant relation between self-citation and impact factor. After omitting self-citation, the level of self-citation in the performance of journals showed that 60% of the titles in the medical science experienced ranking increase, 27% experienced ranking decrease and 13% remained unchanged. Torabian R, Heidari A, Shahrifar M, Khodadi E, Esmaeile Vardanjani SA. The Relation between Self-Citation and Impact Factor in Medical Science Open Access Journals in ISI & DOAJ Databases. Life Sci J 2012;9(4):2206-2209] (ISSN: 1097-8135). http://www.lifesciencesite.com. 32
Experimental Investigation of the Effect of Screw Fastener Spacing on the Local and Distortional Buckling Behavior of Built-Up Cold-Formed Steel Columns
This paper addresses an ongoing experimental and computational effort on the buckling and strength of built-up cold-formed steel (CFS) columns. Specifically, two 6 in. (152 mm) deep lipped channel sections (i.e. the 600S137-54 and 600S162-54 using AISI S200-12 nomenclature) are studied here in a back-to-back, screw-connected form and were chosen for their local and distortional slenderness to study the effect of fastener spacing and layout on local and distortional buckling and collapse behavior. Thirty column tests are completed with concentric loading. The screw spacing is varied from L to L/6, where L is the column length, with and without varying lengths of End Fastener Groups (EFG), which are a prescriptive layout of fasteners at the ends of built-up columns that is required by AISI S100-12 and is intended to insure end rigidity and increase composite action. Results yield two general types of deformation modes: compatible (where the connected webs conform to the same buckling shape) and isolated stud buckling. Buckling loads and half-wavelengths of deformation are shown to be affected by the tighter screw spacings. EFGs increase compatibility of buckling, but prove to be an inefficient (costly) method of fastening studs together. Future work includes expanding the design methods for built-up CFS columns to explicitly account for local and distortional buckling behavior of the built-up section, and to develop efficient numerical tools supporting a new design method under development
Experimental Investigation of the Effect of Screw Fastener Spacing on the Local and Distortional Buckling Behavior of Built-Up Cold-Formed Steel Columns
This paper addresses an ongoing experimental and computational effort on the buckling and strength of built-up cold-formed steel (CFS) columns. Specifically, two 6 in. (152 mm) deep lipped channel sections (i.e. the 600S137-54 and 600S162-54 using AISI S200-12 nomenclature) are studied here in a back-to-back, screw-connected form and were chosen for their local and distortional slenderness to study the effect of fastener spacing and layout on local and distortional buckling and collapse behavior. Thirty column tests are completed with concentric loading. The screw spacing is varied from L to L/6, where L is the column length, with and without varying lengths of End Fastener Groups (EFG), which are a prescriptive layout of fasteners at the ends of built-up columns that is required by AISI S100-12 and is intended to insure end rigidity and increase composite action. Results yield two general types of deformation modes: compatible (where the connected webs conform to the same buckling shape) and isolated stud buckling. Buckling loads and half-wavelengths of deformation are shown to be affected by the tighter screw spacings. EFGs increase compatibility of buckling, but prove to be an inefficient (costly) method of fastening studs together. Future work includes expanding the design methods for built-up CFS columns to explicitly account for local and distortional buckling behavior of the built-up section, and to develop efficient numerical tools supporting a new design method under development
SDII Building Archetype Design v1.0
Building archetypes are fundamental to exploring and demonstrating the seismic behavior of modern structures. No suitable archetypes or prototypes exist in the open literature that focus on steel deck diaphragms for conventional steel buildings. Three dimensional building analysis, with meaningful contributions from the diaphragm in terms of behavior, has not formed the basis for modern seismic standards in steel at this time. The objectives for the SDII building archetypes include the following. Develop a series of 3D steel-framed archetype buildings that explore and document the design of horizontal lateral force resisting systems (LFRSs) with steel deck-based diaphragms as well as vertical LFRSs and the inter-relationship between the two. Provide a series of buildings that form a common basis of comparison for diaphragms in steel-framed buildings much the same way the SAC buildings did for the vertical LFRS. Explicitly explore the impact of the ASCE 7-16 standard, and ASCE 7-16 alternate diaphragm design with Rs=1 and Rs=3 in designs. Inform areas for needed experimentation, and create targets for advancing nonlinear analysis within the full SDII effort. Version 1.0 of this archetype effort includes: (1) a complete slide deck explaining the design of a 12 story steel building archetype using buckling restrained braced (BRB) frames for the vertical LFRS and steel deck with fill for the diaphragm/horizontal LFRS detailed to the ASCE7-16 standard as well as the ASCE7-16 alternate diaphragm provisions with Rs=1 and Rs=3, (2) a series of spreadsheets that provide the complete design calculations for the gravity and lateral systems, (3) a series of computer models (using the SAP structural analysis program), and (4) a literature review of other related building archetypes and justification for developing new building archetypes. (This version has been superseded by v2.0 - see http://jhir.library.jhu.edu/handle/1774.2/62106)American Institute of Steel Construction (AISC), American Iron and Steel Institute (AISI), Steel Deck Institute (SDI), Steel Joist Institute (SJI), Metal Building Manufacturers Association (MBMA), National Science Foundation (NSF
Preozonation and Prechlorination Effects on TOC Removal by Nanofiltration in Water Treatment
ABSTRACT: In this study, NF membrane was used for surface water treatment. The rejection of organic material, measured as Total organic carbon (TOC), by Nanofiltration was examined. The effects of application of pre-ozonation and pre-chlorination on TOC removal are discussed and their performances are compared with the performances of Nanofiltraion system without pretreatment process. In NF, natural organic rejection is high and no pre-treatment are required. Coagulation targets large hydrophobic organics which foul NF membranes by precipitation and gel layer formation. The results showed that TOC removal in Preozonation-coagulation was higher than prechlorinationCoagulation. In addition pretreatment increases Nanofiltration efficiency
Anomaly/Transport in an Ideal Weyl gas
We study some of the transport processes which are specific to an ideal gas
of relativistic Weyl fermions and relate the corresponding transport
coefficients to various anomaly coefficients of the system. We propose that
these transport processes can be thought of as arising from the continuous
injection of chiral states and their subsequent adiabatic flow driven by
vorticity. This in turn leads to an elegant expression relating the anomaly
induced transport coefficients to the anomaly polynomial of the Ideal Weyl gas.Comment: 35 pages, JHEP forma
Phase diagram for non-axisymmetric plasma balls
Plasma balls and rings emerge as fluid holographic duals of black holes and
black rings in the hydrodynamic/gravity correspondence for the Scherk-Schwarz
AdS system. Recently, plasma balls spinning above a critical rotation were
found to be unstable against m-lobed perturbations. In the phase diagram of
stationary solutions the threshold of the instability signals a bifurcation to
a new phase of non-axisymmetric configurations. We find explicitly this family
of solutions and represent them in the phase diagram. We discuss the
implications of our results for the gravitational system. Rotating
non-axisymmetric black holes necessarily radiate gravitational waves. We thus
emphasize that it would be important, albeit possibly out of present reach, to
have a better understanding of the hydrodynamic description of gravitational
waves and of the gravitational interaction between two bodies. We also argue
that it might well be that a non-axisymmetric m-lobed instability is also
present in Myers-Perry black holes for rotations below the recently found
ultraspinning instability.Comment: 1+22 pages, 3 figures. v2: minor corrections and improvements,
matches published versio
Universal thermal and electrical conductivity from holography
It is known from earlier work of Iqbal, Liu (arXiv:0809.3808) that the
boundary transport coefficients such as electrical conductivity (at vanishing
chemical potential), shear viscosity etc. at low frequency and finite
temperature can be expressed in terms of geometrical quantities evaluated at
the horizon. In the case of electrical conductivity, at zero chemical potential
gauge field fluctuation and metric fluctuation decouples, resulting in a
trivial flow from horizon to boundary. In the presence of chemical potential,
the story becomes complicated due to the fact that gauge field and metric
fluctuation can no longer be decoupled. This results in a nontrivial flow from
horizon to boundary. Though horizon conductivity can be expressed in terms of
geometrical quantities evaluated at the horizon, there exist no such neat
result for electrical conductivity at the boundary. In this paper we propose an
expression for boundary conductivity expressed in terms of geometrical
quantities evaluated at the horizon and thermodynamical quantities. We also
consider the theory at finite cutoff outside the horizon (arXiv:1006.1902) and
give an expression for cutoff dependent electrical conductivity, which
interpolates smoothly between horizon conductivity and boundary conductivity .
Using the results about the electrical conductivity we gain much insight into
the universality of thermal conductivity to viscosity ratio proposed in
arXiv:0912.2719.Comment: An appendix added discussing relation between boundary conductivity
and universal conductivity of stretched horizon, version to be published in
JHE
Classification of All 1/2 BPS Solutions of the Tiny Graviton Matrix Theory
The tiny graviton matrix theory [hep-th/0406214] is proposed to describe DLCQ
of type IIB string theory on the maximally supersymmetric plane-wave or
AdS_5xS^5 background. In this paper we provide further evidence in support of
the tiny graviton conjecture by focusing on the zero energy, half BPS
configurations of this matrix theory and classify all of them. These vacua are
generically of the form of various three sphere giant gravitons. We clarify the
connection between our solutions and the half BPS configuration in N=4 SYM
theory and their gravity duals. Moreover, using our half BPS solutions, we show
how the tiny graviton Matrix theory and the mass deformed D=3, N=8
superconformal field theories are related to each other.Comment: 40 pages, 12 figures, v
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