bluuebunny/crossref_metadata_2025_split huggingface dataset:
Buckling Analysis of Cylindrical Shells using Stochastic Finite Element Method with Random Geometric Imperfections
Authors: Li Zheng , Pasternak Hartmut , Geißler Karsten 
Published: September 2022

AbstractThin‐walled cylindrical shells often exhibit buckling failure and the experimental buckling load is usually lower than calculation results from classical theory and simulation without geometrical imperfection. Besides, test results with carefully conducted similar specimens still have substantial scatter due to imperfection sensitivity. The nonlinear analysis with FEM can obtain a high‐precision result comparing the experiment. However, this is almost impossible in practical engineering. The initial geometric imperfections of cylindrical shells are complex and random properties. Theoretically, these geometric imperfections can be described using a random field or a Fourier series representation. After that a random sample of the buckling bearing capacity of the cylindrical shell can be obtained using the stochastic finite element method within the subsequent analysis. This paper presents the investigation of buckling analysis of cylindrical shells under axial compression considering the randomness of initial geometric imperfections, and the stochastic FEM is employed to calculate the statistical sample of the shell‐buckling load based on a series of random fields and Fourier series representation of geometric imperfections.
Numerical Study of Non‐linear Buckling Analysis for Steel and Partial Concrete Encased Composite Columns
Authors: Zogu Pëllumb , Schäfer Markus 
Published: September 2022

AbstractBuckling is a complex phenomenon, influenced by the non‐linear material properties, as yielding of steel, cracking of concrete as well as, slenderness, geometrical imperfection and residual stresses. The design codes provide essential rules for mechanical resistance, stability and safety aspects. However, the current Eurocodes essentially stipulates engineering models that can easily be transferred to classical structural analysis, but often do not guide sufficiently the application and evaluation of advanced numerical analysis.The present study investigates the buckling analysis of steel and partial encased composite columns. Different definitions for geometrical imperfections and residual stresses are considered. The geometrical imperfections are taken into account in accordance with prEN1993‐1‐14 [2]and EN1090‐2 alternatively. The residual stresses are based on prEN1993‐1‐14 [2] and ECCS – Pub. No.33. In addition, analysis without the consideration of residual stresses are investigated. The scope is to assess the non‐linear finite element analysis (GMNIA), comparing the behavior of hot‐rolled and welded steel cross‐section as well as the impact of additional reinforced concrete encasement. Guidance for the numerical analysis for steel and composite columns is developed.
A Complete Assessment of the Moment‐Curvature Relationship of Compressed Steel‐concrete Composite Cross‐sections
Authors: Lemes Ígor J.M. , Lima Pedro H.A. , Barros Rafael C. , Silveira Ricardo A.M. , Chiorean Cosmin G. 
Published: September 2022

AbstractIn the non‐linear evaluation of the behavior of steel, concrete and steel‐concrete composite cross‐sections, increment and iteration strategies are necessary for the complete construction of the moment‐curvature relationship (M‐Φ). For the correct simulation of sections composed of strain‐softening materials, a numerical strategy based on constant force increments does not capture the downward branch of the M‐Φ relationship. Therefore, the present study aims to couple the strain compatibility method to the path‐following strategies to go beyond the critical bending moment points in the construction of the relations that describe the complete cross‐section mechanical behavior. In this context, the generalized displacement technique, which depends on a generalized stiffness parameter, and the minimum residual displacement method, are adapted to the cross‐sectional non‐linear problem. To validate the proposed numerical formulation, the results obtained here are compared with the numerical data available in the literature. Additionally, the softening effect on the concrete was increased to induce descending stretches in the moment‐curvature relationship, and this condition was correctly evaluated.
Application of Fibre Optical Sensors in Push‐out Tests on Composite Steel Truss and Concrete Beams
Authors: Kroyer Robert , Vigneri Valentino , Taras Andreas 
Published: September 2022

AbstractExperimental push‐out tests have been playing an essential role for the evaluation of the structural behaviour of shear connectors in steel‐concrete composite beams along with the development of analytical design guidelines for predicting the respective longitudinal shear capacity. Although standard push‐out tests allow to quantify the global response of the specimen in terms of load‐slip behaviour, numerical simulations are usually needed to broaden the mechanical insight with a special focus to the areas involved in the mechanical failure. This holds in particular for composite steel truss and concrete beams, where a dedicated shear connection does not exist. The shear connection relies instead on a mechanical interlock between the steel parts and the concrete.Modern measurement devices allow expanding the experimental insight to internal mechanisms of combined concrete‐steel failure. This paper reports on the instrumentation of push‐out tests on composite steel truss and concrete (CSTC) beams with the support of a distributed fibre optical sensing (DFOS) system and evaluates the experimental results. The content presents different concepts of fibre installation and discusses the respective rate of success and the measurement ranges along the global load‐slip curves of the push‐out specimens. The results from the DFOS system provide the strain field histories along essential structural elements embedded in concrete within a crucial range of the load‐slip curves. Hereby it was possible to gain more insight into the load‐bearing mechanisms and identify the material component most likely involved in the stiffness degradation of the push‐out specimens.
On the Verification of Beams Subjected to Lateral Torsional Buckling by Simplified Plastic Structural Analysis
Authors: Moscoso Caridad , Kraus Matthias 
Published: September 2022

AbstractPlastic structural analysis may be applied without any difficulty and with little effort for structural member verifications with regard to lateral torsional buckling of doubly symmetric rolled I sections. Suchlike analyses can be performed based on the plastic zone theory, specifically using finite beam elements with seven degrees of freedom and 2nd order theory considering material nonlinearity. The existing Eurocode enables these approaches and the coming‐up generation will provide corresponding regulations in EN 1993‐1‐14. The investigations allow the determination of computationally accurate limit loads, which are determined in the present paper for selected structural systems with different sets of parameters, such as length, steel grade and cross section types. The results are compared to approximations gained by more sophisticated FEM analyses (commercial software Ansys Workbench applying solid elements) for reasons of verification/validation. In this course, differences in the results of the numerical models are addressed and discussed. In addition, results are compared to resistances obtained by common design regulations based on reduction factors χlt including regulations of EN 1993‐1‐1 (including German National Annex) as well as prEN 1993‐1‐1: 2020‐08 (proposed new Eurocode generation). Concluding, correlations of results and their advantages as well as disadvantages are discussed.
Simplified Interaction Conditions and their Accuracy in Doubly Symmetrical I‐Sections
Authors: Ludwig Christian 
Published: September 2022

AbstractDoubly symmetric I‐sections are amongst the most common cross‐sections used in steel construction. Taking the class of the cross‐section into account, its load‐bearing capacity can be verified as either elastic or plastic. Considering plastic load‐bearing capacity has commercial and ecological advantages and it can be verified using interaction conditions specific to a particular cross‐section. In the technical standards and the literature, a variety of interaction conditions are given. The aim of this study is to compare and evaluate frequently occurring combinations of internal forces and moments (N‐My, N‐Mz, N‐My‐Mz und My‐Mz‐Mω). In addition, boundary conditions for the individual interaction conditions are explained in more detail. Extensive parameter studies have shown that the solutions in EN 1993‐1‐1 and prEN1993‐1‐1 lead to uneconomical and partially non‐conservative results. Through the use of the Extended exponent method (EXM) in combination with the Partial internal force method (PIM‐plus), very simple and reliable calculations can be performed.
Influence of Strain‐hardening on the Bending Strength and Rotation Capacity of Welded I‐section Beams
Authors: Studer Patrick , Taras Andreas 
Published: September 2022

AbstractThe bending strength and rotation capacity of welded I‐section beams made of four different steel grades with varying strain‐hardening characteristics are investigated in this paper. Therefore, four point bending tests are carried out on beams with different cross‐sections. These cross‐sections are assigned to cross‐section class 1 and 3 respectively and thus denote cross‐sections with different design approach. The central areas of the beams were scanned to determine the initial imperfections. The newly developed steel grade, which exhibits a pronounced hardening behavior, achieves a higher bending strength as well as a greater rotational capacity compared to the conventional steel grades. With DIC measurements, the deformation field as well as the resulting strains and stresses over the height of the web could be investigated during the tests. By parameterized numerical simulations, it was possible to identify the shape of the initial imperfection as relevant parameter. By comparing the outcome of the numerical simulations with the experimental investigations, a verified numerical model could be developed, which can be used for further investigations on cross‐section classification.
Lateral Bracing Stiffness Requirements for Systems of Parallel Compression Members
Authors: Ziemian Constance , Ziemian Ronald 
Published: September 2022

AbstractPractical models have been developed to determine the threshold stiffness for lateral bracing components used in systems of parallel compression members or sub‐assemblages. Model formulation is based on the analysis of n parallel compression members with intermediate tie‐bracing and flexible anchorages. Intermediate bracing options include both continuous lateral tie‐bracing with flexible shear connectors, and discrete tie‐braces (blocking) directly linking adjacent members without connectors. Anchor bracing cases include both rigid and flexible braces and connectors, and both equal and unequal stiffnesses. Analytical solutions for the threshold stiffness were derived using equilibrium, compatibility, and constitutive relationships for a system that modeled bracing with linear‐elastic springs. The resulting eigenvalue problem is solved with computational efficiency and speed that far exceeds that of a root‐finding solution scheme reliant on symbolic computations. Two approximate expressions for the ideal tie‐brace stiffness have also been developed. Comparisons with the exact solutions indicate satisfactory accuracy for both approximations, with mean percent errors of 1% ‐ 2% for realistic variable values. A design procedure using these approximations is also proposed.
Direct Conversion of Food Waste into 3D Porous Carbon Traps for Selective Adsorption of Cationic Dyes
Authors: Senthamizhan Anitha , Balusamy Brabu , Debellis Doriana , Heredia‐Guerrero Jose Alejandro , Mancini Giorgio , Carzino Riccardo , Ceseracciu Luca , Athanassiou Athanassia , Fragouli Despina 
Published: September 2022

AbstractConversion of waste biomass into valuable functional materials accomplishes the concept of circular economy in the development of sustainable waste management, and also recovery of such resources possibly reduces the requirement of feedstocks. In this scenario, the development of methodologies toward the direct conversion of the raw biomass into solid adsorbent materials without the use of any templates is highly desirable, but exceptionally challenging due to the complexity of the process. Here the direct synthesis of 3D porous carbon traps by a simple, cost‐effective, and template‐free process starting from a kitchen‐based recipe and fermented food waste is described. Precisely, a robust carbon trap is formed with a spongy structure and highly interconnected hierarchical pores after the pyrolysis of a rice‐based foam in the air. The developed materials float on water and interact efficiently with cationic dyes at static conditions. Importantly, such performance of the 3D carbon traps is not affected in the presence of anionic dyes, indicating the excellent selectivity towards the adsorption of cationic dyes. The adsorbent can be easily recovered and reused for up to 3 cycles without releasing any byproducts, thus, without causing hazardous risk of any secondary pollution to the environment.
Sputum cell‐free DNA for detection of alterations of multiple driver genes in lung adenocarcinoma
Authors: Wang Zheng , Li Lin , Wang Yifei , Li Xiaoguang , Xu Yan , Wang Mengzhao , Liang Li , Wu Xiaonan , Tang Min , Li Yuanming , He Shurong , Du Jun , He Lei , Sun Mingjun , Yang Li , Di Jing , Gai Fei , Liu Dongge 
Published: September 2022

BackgroundSputum cell‐free DNA (cfDNA) has been confirmed to be a valued surrogate sample for detection of EGFR mutations in patients with lung adenocarcinoma (LAC). Whether it is suitable for detection of mutations of multiple driver genes has not been reported.MethodsA total of 83 patients with LAC were enrolled and their sputum and paired tumor samples were collected. A next‐generation sequencing (NGS)‐based 10‐gene panel was used to test sputum supernatant‐derived cfDNA and paired tumor DNA. The sputum sediments were used for cytological evaluation.ResultsThe total positive rates of hotspot mutations of the 10 driver genes in sputum cfDNA and matched tissue samples were 65.1% and 77.1%, respectively. The overall detection sensitivity of variants in sputum cfDNA was 81.3% (95% confidence interval [CI], 69.2%, 89.5%) and the specificity was 100% (95% CI, 79.1%, 100%). The sensitivities of testing sputum cfDNA from patients with stage IIIB‐IV was 87.0% (95% CI, 74.5%, 94.1%); the sensitivities of testing sputum cfDNA from patients with malignant sputum was 92.3% (95% CI, 78.0%, 98.0%); and the sensitivity of testing sputum cfDNA from patients with malignant sputum in stage IIIB‐IV were 94.1% (95% CI, 78.9%, 99.0%).ConclusionsThis study demonstrated that sputum cfDNA were successfully used for the detection of multiple driver genes by NGS. Sputum cfDNA could be a valuable surrogate clinical sample for all‐in‐one test of mutations to guide target therapies, especially for patients with advanced LAC and malignant sputum.
Enhanced Host‐Guest Association and Fluorescence in Copolymers from Copper Salphen Complexes by Supramolecular Internalization of Anions
Authors: Hernández‐Pacheco Paulina , Zelada‐Guillén Gustavo A. , Romero‐Ávila Margarita , Cañas‐Alonso Roberto Carlos , Flores‐Álamo Marcos , Escárcega‐Bobadilla Martha V. 
Published: September 2022

AbstractWe describe the synthesis, crystallographic characterization of a new Cu−Salphen compound and its use as a host Lewis‐acid against guest anions in two versions: a) free molecule, b) copolymerized with methyl methacrylate:n‐butyl acrylate (1 : 4‐wt.) as protective co‐monomers. Higher contents in Cu−Salphen yielded larger and more homogeneous polymer sizes. Polymer size together with glass transitions, heat capacity, thermal degradation, guest‐saturation degrees and host‐guest species distribution profiles from spectrophotometric titrations explained growths of up to 630‐fold in K11 and 180000‐fold in K12 for the host's binding site attributable to a solvophobic protection from the macromolecular structure. Spectrofluorimetry revealed blue‐shifted×13–16 larger luminescence for Cu−Salphen in the polymers (λem=488–498 nm) than that of the non‐polymerized counterpart (λem=510–543 nm) and “turn‐on” blue‐shifted enhanced fluorescence upon guest association. We propose a cooperative incorporation of the guests occurring from the outer medium toward internally protected binding site pockets in the random coil polymer conformations.
Photodynamics of Gas‐Phase Pyruvic Acid Following Light Absorption in the Actinic Region
Authors: Hutton Lewis , Curchod Basile F. E. 
Published: September 2022

AbstractThe photochemistry of pyruvic acid has received a large attention due to its relevance to atmospheric chemistry. Pyruvic acid is produced in the troposphere from both biogenic and anthropogenic sources and is a prototypical model for the family of
‐dicarbonyls. What makes the photochemistry of pyruvic acid particularly interesting from a gas‐phase perceptive is its expected decarboxylation upon sunlight absorption. The exact photodynamics leading to this release of CO2 remains elusive. In this work, we used a combination of excited‐ and ground‐state ab initio molecular dynamics to unravel the possible mechanisms leading to the decarboxylation of pyruvic acid. Our calculations highlight the importance of a proton‐coupled electron transfer mechanism taking place in the first excited electronic state and triggering a nonadiabatic transfer of the molecule to the ground electronic state. The decarboxylation takes place in the ground‐electronic state with the concomitant formation of methylhydroxycarbene. We also calculate the photoabsorption cross‐section and wavelength‐dependent quantum yields for pyruvic acid, highlighting the limits of our theoretical formalism.
High‐Throughput Neurite Outgrowth Assay Using GFP‐Labeled iPSC‐Derived Neurons
Authors: Zhang Li , Li Shuaizhang , Xia Menghang 
Published: September 2022

AbstractThe potential neurotoxicity from an increasing number of drugs and untested environmental chemicals creates a need to develop reliable and efficient in vitro methods for identifying chemicals that may adversely affect the nervous system. An important process in neurodevelopment is neurite outgrowth, which can be affected by developmental neurotoxicity. Currently, neurite outgrowth assays rely mainly on staining, which requires multiple sample processing steps, particularly washing steps, that may introduce variation and limit throughput. Here, we describe a neurite outgrowth assay that uses induced pluripotent stem cell (iPSC)–derived human cortical glutamatergic neurons and/or spinal motor neurons labeled with green fluorescent protein (GFP) to test compounds in a high‐content and high‐throughput format. This method enables live and time‐lapse imaging of GFP‐labeled neurons using an assay plate that is continuously imaged at multiple times after chemical treatment. In this article, we describe how to thaw frozen GFP‐labeled neurons, culture them, treat them with a compound of interest, and analyze neurite outgrowth using a high‐content imaging platform. In this assay, GFP‐labeled iPSC‐derived human neurons represent a promising tool for identifying and prioritizing compounds with potential developmental neurotoxicity for further hazard characterization. © 2022 The Authors. Current Protocols published by Wiley Periodicals LLC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.This article was corrected on 23 September 2022. See the end of the full text for details.Basic Protocol 1: Thawing and seeding of iPSC‐derived neuronsBasic Protocol 2: Compound plate preparation and treatment of neuronsBasic Protocol 3: High‐content imaging and analysis
Comparative evaluation of intermediate solutions in prevention of brown precipitate formed from sodium hypochlorite and chlorhexidine gluconate
Authors: Bueso Vashti , Parikh Neha , Terlier Tanguy , Holland Julian N. , Sarmast Nima D. , Jeong Ji Wook 
Published: September 2022

AbstractObjectivesTo evaluate intermediate treatments between sodium hypochlorite and chlorhexidine gluconate irrigations for the prevention of a toxic brown precipitate in root canal therapy.Materials and MethodsThirty‐nine premolars were irrigated with 6% sodium hypochlorite and divided into either: No intermediate treatment; Dry paper points; three different irrigations with 17% ethylenediaminetetraacetic acid, deionized water, or 5% sodium thiosulfate. 2% chlorhexidine gluconate was the final irrigant in all groups. Sectioned teeth were analyzed for brown precipitate intensity and area using stereomicroscopy and components related to para‐chloroaniline using Time‐of‐Flight Secondary Ion Mass Spectrometry (ToF‐SIMS).ResultsStereomicroscopy showed that 5% STS significantly reduced brown precipitate intensity and area as compared with no intermediate irrigation (p < .05, Chi‐square, generalized linear model, and Tukey's multiple comparison tests). Utilizing ToF‐SIMS, 5% sodium thiosulfate was most effective in reducing the components representing para‐chloroaniline and chlorhexidine gluconate.ConclusionThe 5% sodium thiosulfate was most effective among other intermediate treatments, assessed by stereomicroscopy and ToF‐SIMS.
Shade tolerance response of legumes in terms of biomass accumulation, leaf photosynthesis, and chlorophyll pigment under reduced sunlight
Authors: Umesh Mathada Rangappa , Angadi Sangamesh , Begna Sultan , Gowda Prasanna , Prasad P. V. Vara 
Published: September 2022

AbstractLegumes have a distinct morpho‐physiological response to reduced sunlight, but their capacity to adapt to the levels of shading due to intercropping systems is not sufficiently understood. Such adaptation to shade—60% of full sun in terms of physiological attributes—was examined in cowpea (Vigna unguiculata Savi), lablab (Lablab purpureus Adans.), lima bean (Phaseolus lunatus), pigeonpea [Cajanus cajan (L.) Millsp.], and pole bean (Phaseolus vulgaris). Although the capacity of photosynthetic machinery decreased under shade, the capacity continued to exceed the actual rate of photosynthesis. Compared with those under full sun, leaves under shade were thinner (specific weight only 56% of that under full sun), larger (surface area greater by 54.7%), and recorded a 15% higher leaves/stem ratio (by weight) and a 25.6% higher leaves/total dry weight ratio. However, the concentration of chlorophyll pigments per unit weight and per unit surface area was significantly higher in leaves under shade. Water stress was probably higher for leaves under full sun given the higher canopy temperatures and lower relative water content. At final biomass harvest, across the species shading has reduced the biomass 32% in 2009 and 34.6% in 2010 over unshade. Biomass was greater in lima bean (413 g m−2), and pigeonpea (408 g m−2) then lowest in lablab (180 g m−2) and cowpea (216 g m−2). Of the five legumes tested, lablab and cowpea showed the greatest tolerance to shade and therefore are better suited to the low‐light environment of intercropping.