Efficacy of CFRP configurations for shear of RC beams: experimental and NLFE

Ahmed B. Shuraim 국제구조공학회 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.39 No.3

This paper presents the results of an investigation on shear strengthening of RC beams externally reinforced with CFRP composite. A total of six full-scale beams of four CFRP strengthened and two unstrengthened were tested in the absence of internal stirrups in the shear span. The strengthening configurations contained two styles: discrete uniformly spaced strips and customized wide strips over B-regions. The composite systems provided an increase in ultimate strength as compared to the unstrengthened beams. Among the three layouts that had the same area of CFRP, the highest contribution was provided by the customized layout that targeted the B-regions. A comparative study of the experimental results with published empirical equations was conducted in order to evaluate the assumed effective strains. The empirical equations were found to be unconservative. Nonlinear finite element (NLFE) models were developed for the beams. The models agreed with test results that targeting the Bregion was more effective than distributing the same CFRP area in a discrete strip style over shear spans. Moreover, the numerical models predicted the contribution of different configurations better than the empirical equations.

Efficacy of CFRP configurations for shear of RC beams: experimental and NLFE

Shuraim, Ahmed B. Techno-Press 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.39 No.3

This paper presents the results of an investigation on shear strengthening of RC beams externally reinforced with CFRP composite. A total of six full-scale beams of four CFRP strengthened and two unstrengthened were tested in the absence of internal stirrups in the shear span. The strengthening configurations contained two styles: discrete uniformly spaced strips and customized wide strips over B-regions. The composite systems provided an increase in ultimate strength as compared to the unstrengthened beams. Among the three layouts that had the same area of CFRP, the highest contribution was provided by the customized layout that targeted the B-regions. A comparative study of the experimental results with published empirical equations was conducted in order to evaluate the assumed effective strains. The empirical equations were found to be unconservative. Nonlinear finite element (NLFE) models were developed for the beams. The models agreed with test results that targeting the B-region was more effective than distributing the same CFRP area in a discrete strip style over shear spans. Moreover, the numerical models predicted the contribution of different configurations better than the empirical equations.

Charmonium and <i>e</i> ⁺ <i>e</i> ⁻ pair photoproduction at mid-rapidity in ultra-peripheral Pb–Pb collisions at [FORMULA OMISSION]

Abbas, E.,Abelev, B.,Adam, J.,Adamová,, D.,Adare, A. M.,Aggarwal, M. M.,Aglieri Rinella, G.,Agnello, M.,Agocs, A. G.,Agostinelli, A.,Ahammed, Z.,Ahmad, N.,Ahmad Masoodi, A.,Ahmed, I.,Ahn, S. A. Springer Berlin Heidelberg 2013 The European physical journal. C, Particles and fi Vol.73 No.11

<P>The ALICE Collaboration at the LHC has measured the J/<I>ψ</I> and <I>ψ</I>′ photoproduction at mid-rapidity in ultra-peripheral Pb–Pb collisions at [FORMULA OMISSION].</P><P>The charmonium is identified via its leptonic decay for events where the hadronic activity is required to be minimal. The analysis is based on an event sample corresponding to an integrated luminosity of about 23 μb<SUP>−1</SUP>. The cross section for coherent and incoherent J/<I>ψ</I> production in the rapidity interval −0.9<<I>y</I><0.9, are [FORMULA OMISSION] and [FORMULA OMISSION], respectively. The results are compared to theoretical models for J/<I>ψ</I> production and the coherent cross section is found to be in good agreement with those models incorporating moderate nuclear gluon shadowing at Bjorken-<I>x</I> around 10<SUP>−3</SUP>, such as EPS09 parametrization. In addition the cross section for the process <I>γγ</I>→<I>e</I><SUP>+</SUP><I>e</I><SUP>−</SUP> has been measured and found to be in agreement with models implementing QED at leading order.</P>

Evaluation of Three Molecular Methods of Repetitive Element Loci for Differentiation of Mycobacterium avium subsp. paratuberculosis (MAP)

Amr El-Sayed,Abdulwahed Ahmed Hassan,Saleh Natour,Amir Abdulmawjood,Michael Bülte,Wilfried Wolter,Michael Zschöck 한국미생물학회 2009 The journal of microbiology Vol.47 No.3

The aim of the present study is to evaluate the efficiency of three methods to determine the molecular diversity of 34 Mycobacterium avium subsp. paratuberculosis (MAP) strains isolated from 17 cattle herds. The applied methods included the analysis of sequence polymorphism of the mononucleotide (G1 and G2) and trinucleotide sequences (GGT) of the Short Sequence Repeats (SSR) and the determination of size polymorphism of 9 different Mycobacterial Interspersed Repetitive Units (MIRU) and 6 Variable Number Tandem Repeats (VNTR). Sequence analysis of SSR of 34 isolates showed 4, 6, and 2 alleles of G1, G2, and GGT repeats, respectively. The amplification of the investigated 9 MIRU units revealed only two discriminatory genotyping systems (MIRU2 and MIRU3). Out of 6 VNTR PCR differentiation methods, only one method could be recommended for genotyping purposes. The profile 7g-12g-4ggt-II-b-2 of the combination systems G1-G2-GGT-MIRU2-MIRU3-VNTR1658 dominates among the examined isolates and was detected in 14.7% of the isolates. The use of certain repetitive loci of SSR, MIRU, and VNTR techniques in this study showed greater potential than others for the characterization of MAP isolates. The recommended loci can be used for the epidemiological tracing of MAP field strains and to determine the relationships between isolates in different herds.

Freeze-out radii extracted from three-pion cumulants in pp, p–Pb and Pb–Pb collisions at the LHC

Abelev, B.,Adam, J.,Adamová,, D.,Aggarwal, M.M.,Agnello, M.,Agostinelli, A.,Agrawal, N.,Ahammed, Z.,Ahmad, N.,Ahmed, I.,Ahn, S.U.,Ahn, S.A.,Aimo, I.,Aiola, S.,Ajaz, M.,Akindinov, A.,Alam, S.N.,A Elsevier 2014 Physics letters: B Vol.739 No.-

<P><B>Abstract</B></P> <P>In high-energy collisions, the spatio-temporal size of the particle production region can be measured using the Bose–Einstein correlations of identical bosons at low relative momentum. The source radii are typically extracted using two-pion correlations, and characterize the system at the last stage of interaction, called kinetic freeze-out. In low-multiplicity collisions, unlike in high-multiplicity collisions, two-pion correlations are substantially altered by background correlations, e.g. mini-jets. Such correlations can be suppressed using three-pion cumulant correlations. We present the first measurements of the size of the system at freeze-out extracted from three-pion cumulant correlations in pp, p–Pb and Pb–Pb collisions at the LHC with ALICE. At similar multiplicity, the invariant radii extracted in p–Pb collisions are found to be 5–15% larger than those in pp, while those in Pb–Pb are 35–55% larger than those in p–Pb. Our measurements disfavor models which incorporate substantially stronger collective expansion in p–Pb as compared to pp collisions at similar multiplicity.</P>

Facile electrodeposition of high-density CuCo₂O₄ nanosheets as a high-performance Li-ion battery anode material

Pawar, S.M.,Pawar, B.S.,Hou, Bo,Ahmed, A.T.A.,Chavan, H.S.,Jo, Yongcheol,Cho, Sangeun,Kim, Jongmin,Seo, Jiwoo,Cha, SeungNam,Inamdar, A.I.,Kim, Hyungsang,Im, Hyunsik Elsevier 2019 Journal of industrial and engineering chemistry Vol.69 No.-

<P><B>Abstract</B></P> <P>High-density CuCo<SUB>2</SUB>O<SUB>4</SUB> nanosheets are grown on Ni foam using electrodeposition followed by air annealing for a Li-ion battery anode. The anode exhibits a high discharge capacity of 1244mAh/g at 0.1A/g (82% coulombic efficiency) and excellent high-rate performance with 95% capacity retention (1100mAh/g after 200 cycles at 1A/g). The outstanding battery performance of the CuCo<SUB>2</SUB>O<SUB>4</SUB> anode is attributed to its binder-free direct contact to the current collector and high-density nanosheet morphology. The present experimental findings demonstrate that the electrodeposited binder-free CuCo<SUB>2</SUB>O<SUB>4</SUB> material may serve as a safe, low-cost, long-cycle life anode for Li-ion batteries.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Synthesis of high-density CuCo<SUB>2</SUB>O<SUB>4</SUB> nanosheets via electrodeposition method. </LI> <LI> CuCo<SUB>2</SUB>O<SUB>4</SUB> nanosheet electrode exhibits a high discharge capacity of 1244mAh/g at 0.1A/g. </LI> <LI> Excellent rate capability and stability with 95% capacity retention after 200 cycles. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Suppression of ϒ ( 1 S ) at forward rapidity in Pb–Pb collisions at _{s NN} = 2.76 TeV

Abelev, B.,Adam, J.,Adamová,, D.,Aggarwal, M.M.,Agnello, M.,Agostinelli, A.,Agrawal, N.,Ahammed, Z.,Ahmad, N.,Ahmed, I.,Ahn, S.U.,Ahn, S.A.,Aimo, I.,Aiola, S.,Ajaz, M.,Akindinov, A.,Alam, S.N.,A North-Holland Pub. Co 2014 Physics letters. Section B Vol.738 No.-

<P><B>Abstract</B></P> <P>We report on the measurement of the inclusive ϒ ( 1 S ) production in Pb–Pb collisions at <SUB> s NN </SUB> = 2.76 TeV carried out at forward rapidity ( 2.5 < y < 4 ) and down to zero transverse momentum using its <SUP> μ + </SUP> <SUP> μ − </SUP> decay channel with the ALICE detector at the Large Hadron Collider. A strong suppression of the inclusive ϒ ( 1 S ) yield is observed with respect to pp collisions scaled by the number of independent nucleon–nucleon collisions. The nuclear modification factor, for events in the 0–90% centrality range, amounts to 0.30 ± 0.05 (stat) ± 0.04 (syst) . The observed ϒ ( 1 S ) suppression tends to increase with the centrality of the collision and seems more pronounced than in corresponding mid-rapidity measurements. Our results are compared with model calculations, which are found to underestimate the measured suppression and fail to reproduce its rapidity dependence.</P>

Anti-Inflammatory Activity of Pistacia khinjuk in Different Experimental Models: Isolation and Characterization of Its Flavonoids and Galloylated Sugars

Ahmed Esmat,Fahad A. Al-Abbasi,Mardi M. Algandaby,Ashaimaa Y. Moussa,Rola M. Labib,Nahla A. Ayoub,Ashraf B. Abdel-Naim 한국식품영양과학회 2012 Journal of medicinal food Vol.15 No.3

The present study aimed at isolating and elucidating the structure of the main components of Pistacia khinjuk L. and exploring its potential anti-inflammatory effect in different experimental models. The extract was evaluated for antiinflammatory activity by measuring paw volume in three experimental models. Then, prostaglandin E2 (PGE2) level, ear edema, tissue myeloperoxidase (MPO) activity, histopathology, nitric oxide (NO) level, and tumor necrosis factor-a (TNF-a) level were assessed. Seven phenolic compounds, mainly flavonoids and galloylated compounds, were isolated from the aqueous methanol extract: gallic acid (1), methyl gallate (2), quercetin-3-O-b-d-4C1-galactopyranoside (hyperin) (3), myricetin- 3-O-a-l-1C4-rhamnopyranoside (myricitrin) (4), 1,6-digalloyl-b-d-glucose (5), 1,4-digalloyl-b-d-glucopyranoside (6), and 2,3-di-O-galloyl-(a/b)-4C1-glucopyranose (nilocitin) (7). The anti-inflammatory activity was evidenced by decreased carrageenan-induced rat paw edema and PGE2 elevation. In the croton oil–induced ear edema model, MPO activity was significantly inhibited, and inflammatory histopathological changes were ameliorated. In the rat air pouch model, NO generation and TNF-a release were significantly inhibited. The isolation and nuclear magnetic resonance spectral data of compound 6 from the genus Pistacia are revealed for the first time. Also, P. khinjuk L. aqueous methanol extract possesses anti-inflammatory activity in several experimental models.

Formation mechanism of self-organized nano-ripples on quartz surface using femtosecond laser pulses

Ahsan, Md. Shamim,Lee, Man Seop,Hasan, Mohammad Khairul,Noh, Young-Chul,Sohn, Ik-Bu,Ahmed, Farid,Jun, Martin B.G. Elsevier 2015 OPTIK -STUTTGART- Vol.126 No.24

<P><B>Abstract</B></P> <P>This article demonstrates the formation of self-organized nano-ripples on a quartz surface by irradiation of femtosecond laser pulses. Self-oriented nano-ripples are printed on the quartz surface by controlling various laser parameters: average pulse energy, pulse width, and number of laser pulses on each irradiated spot. We validate that the direction of the self-organized nano-ripples are oriented perpendicularly to the laser polarization direction. We also investigate and analyze the dependency of nano-ripples period on various laser parameters including the pulse energy, number of laser pulses, and pulse width. The nano-ripples show increasing trend with the increase of laser energy and pulse width, whereas show decreasing trend with the increase of irradiated laser pulses. We also explain, qualitatively, the formation mechanism of the self-organized nano-ripples on quartz surface.</P>

Experimental Verification of Resistance-Demand Approach for Shear of HSC Beams

Ahmed K. El-Sayed,Ahmed B. Shuraim 한국콘크리트학회 2016 International Journal of Concrete Structures and M Vol.10 No.4

The resistance-demand approach has emerged as an effective approach for determining the shear capacity of reinforced concrete beams. This approach is based on the fact that both the shear resistance and shear demand are correlated with flexural tensile strain from compatibility and equilibrium requirements. The basic shear strength, under a given loading is determined from the intersection of the demand and resistance curves. This paper verifies the applicability of resistance-demand procedure for predicting the shear capacity of high strength concrete beams without web reinforcement. A total of 18 beams were constructed and tested in four-point bending up to failure. The test variables included the longitudinal reinforcement ratio, the shear span to depth ratio, and the beam depth. The shear capacity of the beams was predicted using the proposed procedure and compared with the experimental values. The results of the comparison showed good prediction capability and can be useful to design practice.