Impact of Corner Radius on Cold-formed Steel Member Strength

The objectives of this paper are to expl ore (a) how corners of cold-formed steel members are included or ignored in current design methods, and (b) the effectiveness of recent proposals for modifying the strength prediction for local buckling to account for corners. The imp act of round corners is examined on the behavior and strength of isolated elements and on full members using material and geometric nonlinear collapse analysis with shell finite elements in ABAQUS. Comparisons between the available methods and the nonlinear finite element analysis are completed to explore the regimes in which the methods are accurate, as well as when they are deficient. The current appr oach in the main Specification of AISI-S100-07, which applies no reductions regardless of corner size, is demonstrated to be uncons ervative. Initial recommendations for the design of sections with large corner radi us by effective width and direct strength methods are provided

Improved Reliability Determination When Testing Cold-formed Steel Components

The objectives of this paper are to (a) determine the sensitivity of the reliability calculations in Chapter F of the AISI Specification (AISI-S100-07) to controlling load combinations and loading ratios, and (b) develop a more robust alternative for the use of Chapter F. To complete this study the bias factors and variances for all loading conditions are established. In addition, a range of practical load ratios is agreed upon. Parametric studies are performed to explore load case and load ratio dependency for use in the determination of the resistance factor, Φ; specifically, the pre-factor term CΦ and the load variance term VQ. The parametric studies are simplified into a table that provides load case dependent CΦ and VQ factors. The table is recommended for use in Chapter F reliability analysis of new products

Optimization and One-Step Purification of Recombinant V Antigen Production from Yersinia pestis

The purpose of this study was to develop an efficient and inexpensive method for the useful production of recombinant protein V antigen, an important virulence factor for Yersinia pestis. To this end, the synthetic gene encoding the V antigen was subcloned into the downstream of the intein (INT) and chitin-binding domain (CBD) from the pTXB1 vector using specific primers. In the following, the produced new plasmid, pTX-V, was transformed into E. coli ER2566 strain, and the expression accuracy was confirmed using electrophoresis and Western blotting. In addition, the effects of medium, inducer, and temperature on the enhancement of protein production were studied using the Taguchi method. Finally, the V antigen was purified by a chitin affinity column using INT and CBD tag. The expression was induced by 0.05 mM IPTG at 25 °C under optimal conditions including TB medium. It was observed that the expression of the V-INT�CBD fusion protein was successfully increased to more than 40 of the total protein. The purity of V antigen was as high as 90. This result indicates that V antigen can be produced at low cost and subjected to one-step purification using a self-cleaving INT tag. © 2020, Springer Science+Business Media, LLC, part of Springer Nature

Towards the Design of Cold-formed Steel Foam Sandwich Columns

In this paper a design method for the compressive capacity of sandwich panels comprised of steel face sheets and foamed steel cores is derived and verified. Foamed steel, literally steel with internal voids, provides the potential to mitigate many local stability issues through increasing the effective width-to thickness of the component for the same amount of material. Winter’s classical effective width expression was generalized to the case of steel foam sandwich panels. The provided analytical expressions are verified with finite element simulations employing brick elements that explicitly model the steel face sheets and steel foam cores. The closed-form design expressions are employed to conduct parametric studies of steel foam sandwich panels with various face sheet and steel foamed core configurations. The studies show the significant strength improvements possible with steel foam sandwich panels when compared with plain steel sheet/plate

Celecoxib as an Adjuvant to Fluvoxamine in Moderate to Severe Obsessive-compulsive Disorder: A Double-blind, Placebo-controlled, Randomized Trial

Introduction: A growing body of evidence implicates inflammatory cascades in the pathophysiology of obsessive-compulsive disorder (OCD), making this pathway a target for development of novel treatments. Methods: 50 outpatients with moderate to severe OCD participated in the trial, and underwent 10 weeks of treatment with either celecoxib (200 mg twice daily) or placebo as an adjuvant to fluvoxamine. Participants were investigated using Yale-Brown Obsessive Compulsive Scale (Y-BOCS). The main outcome measure was to assess the efficacy of celecoxib in improving the OCD symptoms. Results: General linear model repeated measures demonstrated significant effect for time � treatment interaction on the Y-BOCS total scores F (1.38, 66.34)=6.91, p=0.005. Kaplan-Meier estimation with log-rank test demonstrated significantly more rapid response in the celecoxib group than the placebo group (p<0.001). There was no significant difference in adverse event frequencies between the groups. Discussion: The results of the current study suggest that celecoxib could be a tolerable and effective adjunctive treatment for more rapid and more satisfying improvements in OCD symptoms. © Georg Thieme Verlag KG Stuttgart, New York

Structural Stability

IASS-IACM 2008 Session: Structural Stability -- Session Organizer: Herbert MANG (Technical University of Vienna) -- Plenary Lecture: Abstract, Slides and Video: "Answers to three not quite straightforward questions in structural stability" by Andreas STEINBOECK, Gerhard HOEFINGER, Xin JIA, Herbert A. MANG (Technical University of Vienna) -- Keynote Lecture: "Limit-point and postbuckling behavior of steel trusses under thermal and mechanical loadings" by Yeong Bin YANG , T.J. LIN (National Taiwan University) -- "Modeling thin-walled cold-formed steel members and systems" by Benjamin W. SCHAFER , R. H. SANGREE, Cristopher MOEN, M. SEIF, Y. SHIFFERAW, V. ZEINODDINI, Z. J. LI, O. IUORIO, Y. GUAN (Johns Hopkins University) -- "Multi parametrical instability of straight bars" by Jan B. OBREBSKI (Warsaw University of Technology) -- "The effect of predetermined delaminations on buckling and post-buckling behavior of spatial composite timber beams and frames" by Miran SAJE , Urban RODMAN, Dejan ZUPAN, Igor PLANINC (University of Ljubljana) -- Keynote Lecture: "Buckling and sensitivity analysis of imperfect shells involving contact" by Karl SCHWEIZERHOF , Eduard EWERT (University of Karlsruhe) -- Keynote Lecture: "Determining the stability of tensegrities and generic global rigidity" by Robert CONNELLY (Cornell University) -- "Initial imperfection identification in shell buckling problems" by Christopher J. STULL , Christopher J. EARLS, Wilkins AQUINO (Cornell University) -- "Buckling phenomena, analysis and design of axially compressed cylindrical shells with co-existent external pressure" by Werner GUGGENBERGER , Medhanye B. TEKLEAB (TU Graz