bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sequestering the 5′‐cap for viral RNA packaging
Authors: Ding Pengfei , Summers Michael F. 
Published: September 2022

AbstractMany viruses evolved mechanisms for capping the 5′‐ends of their plus‐strand RNAs as a means of hijacking the eukaryotic messenger RNA (mRNA) splicing/translation machinery. Although capping is critical for replication, the RNAs of these viruses have other essential functions including their requirement to be packaged as either genomes or pre‐genomes into progeny viruses. Recent studies indicate that human immunodeficiency virus type‐1 (HIV‐1) RNAs are segregated between splicing/translation and packaging functions by a mechanism that involves structural sequestration of the 5′‐cap. Here, we examined studies reported for other viruses and retrotransposons that require both selective packaging of their RNAs and 5′‐RNA capping for host‐mediated translation. Our findings suggest that viruses and retrotransposons have evolved multiple mechanisms to control 5′‐cap accessibility, consistent with the hypothesis that removal or sequestration of the 5′ cap enables packageable RNAs to avoid capture by the cellular RNA processing and translation machinery.
Comprehensive studies on building a scalable downstream process for mRNAs to enable mRNA therapeutics
Authors: Cui Tingting , Fakhfakh Kareem , Turney Hannah , Güler‐Gane Gülin , Toloczko Aleksandra , Hulley Martyn , Turner Richard 
Published: September 2022

AbstractIn recent years, mRNA‐based therapeutics have been a fast‐growing new class of biologics that can, in principle, encode any protein(s) directly in patients to treat various diseases. mRNA vaccines have been proven to work efficiently, have high potency, and can be rapidly developed and deployed, which is critical for a quick responses in the case of a pandemic. Such agile development is enabled by rapid synthesis of RNA in vitro using recombinant enzymes rather than relying on lengthy and complex cell culture processes. mRNA exhibits physical and chemical properties differing from protein‐based therapeutics. It is highly negatively charged and the hydroxyl group makes mRNA less stable and more susceptible to hydrolysis and nucleophilic cleavage. This novel work shares comprehensive studies carried out to compare the performance of various mRNA purification strategies by considering its scalability and critical quality attributes. In addition, the paper provides insights on how to establish a scalable mRNA purification process that consists of ultrafiltration/diafiltration and chromatography steps with good recoveries. Alternative Oligo(dT) based columns were further explored aiming to improve total process recovery. With Oligo(dT) as a capture step, overall recoveries of 70% can be achieved for mRNAs studied here that encode anti‐influenza immunoglobulin G monoclonal antibodies.
Direct Evaluation of the Sensitivity of the Nonlinear Critical Point to Geometrical Imperfections
Authors: Magisano Domenico , Garcea Giovanni 
Published: September 2022

AbstractA generalized path‐following method is proposed for the direct evaluation of the critical point sensitivity to geometrical imperfections expressed as combination of given shapes. After a finite element discretization, the critical point is defined by a system of nonlinear algebraic equations imposing equilibrium and critical condition according to the null vector method. An arc‐length equation is added to follow a path of critical points in the imperfection space. The solution of the extended system by a Newton scheme requires a Jacobian involving also the derivatives of the critical condition with respect to the FE DOFs and the derivatives of all the problem equations with respect to the imperfection parameters. An analytical and efficient computation of the Jacobian is achieved by a solid‐shell model and a strain‐based model of the imperfection. In addition, a mixed stress‐displacement iterative scheme is devised for a highly efficient and robust solution. Finally, the derivatives of the critical point with respect to the imperfection parameters are also obtained analytically and can be used to generate a gradient‐based critical path for a quick search of the worst‐case imperfection. A compressed cold‐formed lipped channel beam is analyzed as a case study.
Shape Optimisation of Cold‐Formed Steel Cross‐Sections with Longitudinal Intermediate Stiffeners
Authors: Neves Marcos , Basaglia Cilmar , Camotim Dinar 
Published: September 2022

AbstractThis paper reports the development, numerical implementation and application of a novel methodology to perform a multi‐objective shape optimisation of conventional cold‐formed steel (CFS) cross‐section shapes with longitudinal intermediate stiffeners, manufactured by bending the steel sheets with roll‐forming machines. The methodology is based on a Genetic Algorithm (GA) and aims at maximising the compressive and/or flexural ultimate strength of CFS members currently used in industry with respect to local, distortional and local‐distortional interactive failures. The design approach adopted to estimate the member ultimate strengths is based on the Direct Strength Method (DSM) and Generalised Beam Theory (GBT) is used to calculate the elastic buckling loads and moments. The proposed methodology consists of adding small intermediate stiffeners, whose possible locations are pre‐defined in accordance with a map of executable fold‐line positions – the original cross‐section typology, overall dimensions and wall angles are retained. The application and potential of the developed GA‐based code is illustrated by addressing the optimisation of conventional lipped channel, lipped zed and rack cross‐section shapes for CFS members subjected to compression, bending or compression and bending.
Design Assisted by Finite Element of Z‐Purlins with Overlapping under Gravity Loading
Authors: Gîrbacea Ioan Andrei , Ungureanu Viorel 
Published: September 2022

AbstractCold‐formed steel Z‐purlins are generally designed to span continuously over rafters. The bending moment continuity or semi‐continuity is obtained by overlapping the profiles or using a sleeved connection. Lapped connections are regarded as superior in terms of stiffness and resistance compared to their sleeved counterpart. A finite element model was developed and validated against experimental results to be used in a parametric study. The study investigated the influence of parameters such as: cross‐section dimensions, span length, symmetrical and unsymmetrical overlap lengths, connection detailing, trapezoidal sheeting thickness and connection. The numerical results show that the mechanical behavior of overlapped purlins loaded by gravity is mainly influenced by the span and the length of overlapping. The connection detailing is particularly important for short overlaps.
The Influence of Eccentricity on the Behaviour of Thin‐Walled Cold‐Formed Steel Members with Open Cross‐Sections under Compression
Authors: Bodea Florin Liviu , Both Ioan , Czechowski Leszek , Jankoswki Jacek , Kotełko Maria , Ungureanu Viorel 
Published: September 2022

AbstractThin‐walled cold‐formed steel elements represent an attractive structural solution due to the fast manufacturing and erection time on site. Their small thickness leads to imperfection and eccentricities sensitivities. An experimental program was performed on short members with lipped channel cross‐section of 150×60×20×2 mm, subjected to (1) eccentric compression about the minor axis, in a range of eccentricities between −40 mm and +40 mm and (2) eccentric compression about the major axis, in a range of eccentricities between 0 mm and +90 mm. Shortening of all specimens was measured in two ways, i.e. (1) using the displacement gauge integrated with the machine crosshead beam and (2) from deformation fields obtained using Digital Image Correlation system (DIC). The quantitative results, presented as ultimate loads vs eccentricity curve, emphasize the influence of the eccentric load on the capacity of the element and on the type of plastic mechanism formation. Finite element analyses were performed to simulate the behaviour of short members in eccentric compression using the commercial FE software ABAQUS/CAE. Static non‐linear analyses were carried out in displacement control. Both geometrical and material non‐linearities were included. The experimental results confirm two different basic failure mechanisms depending on the load eccentricity direction applied to the studied members with open cross‐section.
Mechanical Properties of the Component “Column Web in Compression” in Steel Beam‐to‐column Joints
Authors: Jaspart Jean‐Pierre , Corman Adrien , Demonceau Jean‐François 
Published: September 2022

AbstractThe component method is widely used nowadays for the analytical prediction of the mechanical properties (rotational elastic stiffness, design resistance and ductility/deformation capacity) of steel and composite beam‐to‐column joints. Eurocode 3 Part 1‐8 (EN 1993‐1‐8) provides expressions for the evaluation of the properties of many different joint components. However, a quick examination of EN 1993‐1‐8 highlights a glaring disproportion between the quantity of information related to rotational stiffness and plastic resistance, and that related to ductility and deformation capacity. For the latter, only few recommendations are provided, sometimes in line, and sometimes even not with the component approach itself. Present paper concerns one of these components, the “column web in transverse compression” (CWC), for which no information is basically available in terms of ductility. An original procedure for the prediction of the plastic deformation capacity is presented. It relies on a preliminary evaluation of the four main component properties: elastic stiffness, plastic resistance, post‐plastic stiffness and ultimate resistance. Through this study, more accurate analytical formulae than those provided by EN 1993‐1‐8 for the evaluation of the plastic resistance are also suggested. All the developments are validated through extensive comparisons with available experimental tests.
Structural Response of Wire Arc Additively Manufactured Steel Bolted Connections under Single Shear
Authors: Guo Xi , Kyvelou Pinelopi , Ye Jun , Teh Lip H. , Gardner Leroy 
Published: September 2022

AbstractAn experimental investigation into the structural performance of wire arc additively manufactured (WAAM) steel single‐lap shear bolted connections is presented in this paper. Sixty specimens of different thicknesses, printing strategies and geometric features, including end distances and plate widths, were manufactured using steel wire of a nominal yield strength of 420 MPa and subjected to single shear lap tests. The test results are analysed while the observed failure modes, featuring shear‐out, net section tension fracture, end‐splitting, localised tearing and curl‐bearing failure, are discussed. Digital image correlation (DIC) was used for detailed monitoring and visualisation of the surface strain fields that developed during testing, providing valuable insight into the developed failure mechanisms. The experimental results, which generally followed the anticipated trends, were used to assess the applicability of current design specifications developed for conventional steel bolted connections to WAAM steel bolted connections. It was found that both the cold‐formed steel specifications (AISI S100 and AS/NZS 4600) and the structural steel specifications (AISC 360 and EN 1993‐1) yield considerable overestimations or underestimations of the test capacities, depending on the specimen geometry. Further research is underway to underpin the development of improved design provisions.
Safety Assessment for Capacity Design of Bolted Steel Connections in Tension
Authors: Snijder Hubertus H. , Knipping Jitske B.N. , Maljaars Johan , Teeuwen Paul A. 
Published: September 2022

AbstractCapacity design for bolted connections in tension means that yielding of the gross cross‐section is decisive over the ultimate resistance of the net cross‐section. If the requirement for capacity design is met, ductile connection behavior is achieved, and brittle failure is avoided. However, in many practical cases the bolt holes are too large to satisfy the current capacity design requirement of EN 1993‐1‐1. In this capacity design requirement, both failure criteria involved, plastic resistance of the gross cross‐section and ultimate resistance of the net cross‐section, are considered independently with their own partial factors. This may be overly conservative. The goal of the research is to determine an improved capacity design requirement such that bigger bolt holes can be allowed without hampering safety. Both partial factors and the factor 0,9 in the net cross‐section resistance are combined in one factor. With the use of a Monte Carlo simulation a new capacity design requirement with its own combined factor is developed. Several distributions for dimensions and steel properties are used as input for the Monte Carlo simulation. The correlation between the yield stress and the ultimate strength is considered as well. In the Monte Carlo simulation, also a model factor is used. The current combined factor for the capacity design requirement is 1.39. Based on the research performed, it can be concluded that this is very conservative and that the value of the combined factor can be lowered to 1.05.
Structural Response and Design of Austenitic Stainless Steel I‐section Beam‐columns Undergoing Flexural‐Torsional Buckling
Authors: Kucukler Merih , Gardner Leroy 
Published: September 2022

AbstractIn this paper, the flexural‐torsional buckling response of austenitic stainless steel I‐section beam‐columns is investigated. Finite element simulations are performed with the aim of analysing the parameters affecting the behaviour of the studied members. The accuracy and safety of the existing design provisions of the European structural stainless steel design standard EN 1993‐1‐4 (2015) are assessed. A new method providing more accurate ultimate resistance predictions for austenitic stainless steel I‐section beam‐columns undergoing flexural‐torsional buckling is put forward. The higher accuracy, safety and reliability of the proposed design rules relative to EN 1993‐1‐4 (2015) are demonstrated and the new proposals have now been included in the revised Eurocode – prEN 1993‐1‐4 (2021).
Design Buckling Resistance of High Strength Steel Members
Authors: da Silva Luís Simões , Tankova Trayana , Rodrigues Filipe 
Published: September 2022

AbstractEN 1993‐1‐1 gives stability design rules for columns, beams and beam‐columns up to S460, whereas EN 1993‐1‐12 gives additional guidance for S500 up to S700 (based mainly on numerical work available at the time). Recent studies on flexural buckling of welded H, I and box columns in steel grades S460 to S960, even though limited, show that improved curves can be used for members in high strength steel (HSS). The research project RUOSTE also reported improved buckling curves for HSS box and tubular sections compared to those in Table 6.2 of EN 1993‐1‐1. This improved behaviour is usually attributed due to the improved material properties but mainly due to the more favourable residual stress distribution.Recently, within the European Project STROBE evaluation of the European stability design rules was carried out covering columns, beams, and beam‐columns. The research was based on experimental programme covering 20 full‐scale tests, residual stress measurements, advanced numerical models, analytical derivations, and statistical evaluation. Finally, it was possible to provide new, more relaxed recommendations for the buckling curve selection for HSS members.This paper provides a summary of the project conclusions regarding the stability design of steel members in high strength steel, where firstly a brief overview of the experimental results is presented, followed by the numerical parametric study, results evaluation, and discussion.
Calibrated Design Model for the Compression Capacity of Angle Members with Welded Joints Including Accurate Joint Stiffness
Authors: Unterweger Harald , Kettler Markus , Zauchner Paul 
Published: September 2022

AbstractDue to the commonly eccentric connection on only one angle leg (bolted or welded), additional bending moments are acting on the member, leading to a complex load carrying behavior with flexural and/or lateral torsional buckling phenomena. Furthermore, type and size of rotational restraints at the member's ends (provided by the adjacent structure) significantly influence the compression member capacity of these members.Within this paper, a recently developed design model for angle members in compression is introduced. The presented method allows for calculating the internal forces based on elastic second order theory for an individual member with eccentricities and rotational spring stiffness at both ends. This calculation can be carried out by means of conventional structural analysis software. Detailed analytical equations for the estimation of appropriate spring stiffness values for several practical applications in buildings with two‐bolt connections have recently been presented by the authors. This relationship is now enhanced by means of additional formulae for angle members welded to the adjacent structure. Detailed background information on the derivation of these newly developed spring stiffness formulae is given. Finally, the accuracy of the design model for this enlarged range of application for welded angle members is shown through comparison with sophisticated finite element calculations, code provisions and experimental tests from literature.
Influence of the Shape of Initial Imperfections on Single Web and Flange Steel Plates at Elevated Temperatures
Authors: Possidente Luca , Tondini Nicola 
Published: September 2022

AbstractIn the last decades the buckling of steel members in fire has attracted the attention of the scientific community, but considerations about the choice of the initial imperfections have been rarely the focus of scientific publications. However, initial imperfections play a primary role in the definition of the resistance, especially when local buckling is investigated. Although the lowest buckling mode is usually employed, the definition of an appropriate imperfection shape providing, for instance, the lowest resistance is not straightforward. Even more so when the local behaviour at elevated temperatures is being studied, since the buckling behaviour may differ from the one at ambient temperature, owing to the steel degradation and possible load redistributions. In this paper steel plates in compression at elevated temperatures are studied considering different shapes of imperfection. A parametric analysis on webs and flanges composing Class 4 HE and IPE sections with S355 steel grade is presented, considering five temperatures in a relevant range (400–800°C) and several plate aspect ratios. The influence of the imperfection shapes on the resistance depending on the temperature, the length and the slenderness of the web and flange plates is discussed.
Numerical Investigation on the Thermal Behaviour of Steel‐reinforced CFST Columns in Fire
Authors: Medall David , Espinós Ana , Albero Vicente , Ibáñez Carmen , Romero Manuel L. 
Published: September 2022

AbstractIn previous research, the authors highlighted the limited fire resistance of slender concrete‐filled steel tubular (CFST) columns. A possible solution for enhancing the fire resistance of such columns consists of embedding an open steel profile within the concrete infill of the CFST section, generating the so‐called steel‐reinforced concrete‐filled steel tubular (SR‐CFST) section, where the inner steel profile results thermally protected by the surrounding concrete, thus delaying its degradation at elevated temperatures. This strategy may result beneficial in the fire situation as compared to other sectional configurations where the steel parts are directly exposed to the heat source.In this paper, a two‐dimensional finite element model will be developed for studying the thermal behaviour of SR‐CFST columns and validated by comparing the temperature distribution results with experimental tests available in the literature. The numerical model will be subsequently used to carry out parametric studies, in order to analyse the influence of the different parameters, such as the cross‐section shape, outer tube thickness or the inner steel profile sectional dimensions over the thermal response of these composite sections when subjected to fire.Finally, a simplified temperature distribution proposal will be developed, which may help practitioners for a fast evaluation of the cross‐sectional temperature field of SR‐CFST columns at a given fire resistance period by assigning an equivalent temperature to each component of the composite section (hollow steel tube, concrete encasement and inner steel profile). This simplified temperature proposal may result helpful when evaluating the sectional capacity of SR‐CFST columns in fire, by using a single strength and stiffness value for each component of the composite cross‐section corresponding to its temperature.
Design Procedure for Stainless Steel Slender I Section Members in Bending
Authors: Šorf Marek , Jandera Michal 
Published: September 2022

AbstractStainless steel welded I sections are used in structures not as often as cold‐rolled hollow sections or laser‐welded sections. But the design rules for both local buckling of very slender sections as well as lateral torsional buckling reduction factors are based on a very limited experimental and numerical research. For this reason, a new research covering these phenomena was carried out at the Czech Technical University in Prague. The contribution shows a numerical parametric study of welded slender stainless steel I‐section beams as a follow‐up of previous experimental program. The numerical study based on a validated FE model was carried out to develop a procedure for LTB of I section beams. The proposal follows the procedure of Taras, which is part of prEN 1993‐1‐1:2019, where modified constants are proposed. It was also found, that the local buckling reduction factor used in EN 1993‐1‐4:2006 may be unsafe for ordinary welded sections. The procedure in the Eurocode was developed mainly for SHS/RHS and laser‐welded sections. These fabrication methods result in significantly lower geometrical imperfections and slightly lower residual stresses than common welding methods (e.g. MIG). Therefore, a safe procedure proposal for Class 4 welded section resistance was also provided, despite not being the focus of the paper.
Applicable Equivalent Bow Imperfections in GMNIA for Eurocode Buckling Curves – in Case of Box Sections
Authors: Somodi Balázs , Bärnkopf Erzsébet , Kövesdi Balázs 
Published: September 2022

AbstractThe flexural buckling resistance of compressed columns is typically determined using the flexural buckling curves of EN1993‐1‐1. With advances in computing capabilities, it has become possible to obtain the flexural buckling resistance as a result of a geometrically and materially nonlinear analysis (GMNIA) using imperfections. In design practice, equivalent geometric imperfections are usually used, but their values are calibrated against GNIA analysis. In the present research work, welded box‐section columns are investigated and a proposal for relative slenderness and yield strength dependent equivalent geometric imperfection magnitudes is developed. The required equivalent bow imperfection magnitude is determined to achieve the same resistance level as the calculation according to Eurocode‐based buckling curves. GMNIA analysis are conducted on simply supported columns subjected to concentrated force. The steel grade varied between S235 and S960. Several different section geometries are studied, the relative slenderness ratio is varied between 0.3 and 2.2. Design curve is fitted to the results and recommendation is given for applicable equivalent geometric imperfection magnitudes for steel welded box‐section columns.