bluuebunny/crossref_metadata_2025 huggingface dataset:
Building a Better Li‐Garnet Solid Electrolyte/Metallic Li Interface with Antimony
Authors: Dubey Romain , Sastre Jordi , Cancellieri Claudia , Okur Faruk , Forster Alexander , Pompizii Lea , Priebe Agnieszka , Romanyuk Yaroslav E. , Jeurgens Lars P. H. , Kovalenko Maksym V. , Kravchyk Kostiantyn V.
Published: September 2021

The deployment of Li‐garnet Li7La3Zr2O12 (LLZO) solid‐state electrolytes in solid‐state batteries is severely hampered by their poor wettability with metallic Li. In this work, Sb is presented as a compelling interfacial layer allowing superior wetting of Li onto a LLZO surface, resulting in a remarkably low Li/LLZO interfacial resistance of 4.1(1) Ω cm2. An atomistic insight into Sb‐coated LLZO interface using soft and hard X‐ray photoelectron spectroscopy and focused ion beam time‐of‐flight secondary ion mass spectrometry shows the formation of a Li‐Sb alloy as an interlayer. It is determined that the Li/Sb‐coated LLZO/Li symmetrical cells exhibit a high critical current density of up to 0.64 mA cm−2 and low overpotentials of 40–50 mV at a current density of 0.2 mA cm−2 without applying external pressure. The electrochemical performance of Sb coated‐LLZO pellets is also assessed with an intercalation‐type V2O5 cathode. Li/Sb‐coated‐LLZO/V2O5 full cells deliver stable capacities of around 0.45 mAh cm−2, with a peak current density of 0.3 mA cm−2.
Influence of oral nutritional agents rich in soluble dietary fiber on intestinal flora of elderly men with malnutrition
Authors: Yu Dongni , Cheng Mingyue , Guo Lixin , Liu Wenli , Liu Ye , Ning Kang , Tong Yigang , Yan Xuejiao , Qiu Lei , Qi Haimei
Published: September 2021

Objective

Observe the influence of oral nutritional agents rich in soluble dietary (enteral nutritional suspension [TPF‐DM]) on intestinal flora of elderly male subjects with malnutrition.

Method

Seventy‐eight subjects with good nutrition were considered as the healthy control group. Twenty‐eight male subjects who had malnutrition and were older than 70 years were included and randomly divided into the short‐term (3 months) intervention group (n = 20) and the long‐term (12 months) group (n = 8). They were provided with enteral nutritional suspension (TPF‐DM) 500 mL/day or maximum tolerance dose, so as to observe the changes in nutrition‐related indexes and intestinal flora after the elderly take enteral nutritional suspension (TPF‐DM).

Results

(1) For elderly male subjects with malnutrition, their body weight, body mass index, hemoglobin, total protein, and albumin were significantly lower than the control group with favorable nutrition. (2) There were obvious differences in intestinal flora between healthy elderly male subjects and those with malnutrition. After the treatment of enteral nutritional suspension (TPF‐DM), intestinal flora of the malnourished elderly subjects showed recovery toward the healthy elderly subjects. The obvious gradient changes of the flora were mainly in the bacteroidetes, firmicutes, and proteobacteria phyla, and the relative abundance of CAG2 clusters in the malnourished group was higher than that in the healthy control group, and the relative abundance decreased after long‐term treatment, and the change approached the healthy control group. The relative abundance of CAG3 and CAG6 clusters in the malnourished group was lower than that in the healthy control group, and the relative abundance increased after long‐term treatment, and the change approached the healthy control group.

Conclusion

Malnutrition has obvious impact on intestinal flora of the elderly. Enteral nutritional suspension (TPF‐DM) not only prevents the further decline in the state of nutrition but also helps the recovery in intestinal flora of the elderly. Long‐term application can produce better effects.
Antenatal diagnostic dilemma in a pseudodominant pedigree with lamin‐B receptor (LBR)‐related regressive spondylometaphyseal dysplasia
Authors: Turgut Gozde Tutku , Güleç Çağrı , Sarac Sivrikoz Tugba , Kale Hamdi , Karaman Birsen , Nishimura Gen , Altunoglu Umut
Published: September 2021

The lamin‐B receptor (LBR) encodes a dual‐functioning inner nuclear membrane protein essential for cholesterol biosynthesis and chromatin organization. LBR pathogenic variants cause distinct phenotypes due to the dual function of LBR, including Pelger–Huët anomaly (PHA), PHA with mild skeletal anomalies (PHASK; MIM# 618019), LBR‐related regressive type of spondylometaphyseal dysplasia (LBR‐R‐SMD), Greenberg dysplasia (MIM# 215140). We here report the first case with radiological manifestations of LBR‐R‐SMD in the fetal period, and milder skeletal findings in the similarly affected father. Direct sequencing of LBR revealed homozygous c.1534C>T (p.Arg512Trp) in exon 12 in both affected individuals. Our report further refines the early phenotype in LBR‐R‐SMD, and demonstrates that the p.Arg512Trp mutation is associated with PHA. We propose that LBR‐R‐SMD should be considered as a differential diagnosis in pregnancies with sonographic evidence of short and bowed tubular bones with narrow thorax. Evaluating peripheral blood smears of expectant parents for the presence of PHA may lead to a clinical diagnosis, allowing for comprehensive prenatal genetic counseling.
Surface modification of cellulose nanocrystals towards new materials development
Authors: Shi Zhenxu , Li Shufang , Li Mingxia , Gan Lin , Huang Jin
Published: September 2021

Cellulose nanocrystals (CNCs) are a kind of sustainable nanoparticle from biomass, which are widely used as reinforcing filler and assembly building block for high‐performance composites and function materials including biomaterial, optics, and so forth. Here, their unique advantages in material applications were reviewed based on their rod‐like morphology, crystalline structure, dimension‐related effects, and multi‐level order structure. Then, we focused on the molecular engineering of CNCs, including the structure and physicochemical properties of their surface, along with surface modification methods and steric effects. We further discussed the performance‐improvement and functionalization methods based on multi‐component complex systems, together with the effects of surface molecular engineering on the performance and functions. Meanwhile, methods of optimizing orientation in uniaxial arrays were discussed along with those of enhancing photoluminescence efficiency via surface chemical modification and substance coordination. In the end, we prospected the design, development, and construction methods of new CNCs materials.
Electrospun polyacrylonitrile nanofibrous membranes supported with montmorillonite for efficient PM2.5 filtration and adsorption of Cu (II) ions
Authors: Bansal Priya , Batra Radhika , Yadav Reetu , Purwar Roli
Published: September 2021

In this study, we have fabricated polyacrylonitrile/montmorillonite (PAN/Mt) nanofibrous nanocomposites with variation in concentration of Mt from 0.25% to 1.00%. The electrospinning process developed PAN/Mt nanofibrous nanocomposites having reduced fiber diameters and high surface roughness as observed in Field emission scanning electron microscopy. The nanocomposite nanofibers were characterized by X‐ray diffraction (XRD) and thermogravimetric analyzer for intercalation and thermal stability respectively. PAN/Mt nanofibrous nanocomposites were tested for their water vapor transmission rate, air permeability, burst strength, and tensile strength. The filtration efficiency of 0.75% PAN/Mt nanofibrous nanocomposite was found to be 98.7% for PM2.5 particles present in air with a pressure drop of 46.8 Pa. The adsorption of copper (II) (Cu (II)) ions using 0.75% PAN/Mt nanofibrous nanocomposites has also been studied. The effect of contact time and initial concentration of adsorbent on the adsorption of Cu (II) ions have been analyzed. It was found that the PAN/Mt nanofibrous membranes follows pseudo‐second‐order kinetic model and Langmuir adsorption isotherm for the adsorption of Cu (II) ions from aqueous solutions. This study suggests the potential implication of PAN/Mt nanofibrous nanocomposites for filtration of PM2.5 and adsorption of metal ions.
Immobilization of an organophosphorus compound on polypropylene‐g‐poly(glycidyl methacrylate) polymer support and its application in scandium recovery
Authors: Madrid Jordan F. , Barba Bin Jeremiah D. , Pomicpic Janronel C. , Cabalar Patrick Jay E.
Published: September 2021

Scandium is a rare earth element that has a wide range of uses in modern technology. The conventional recovery of scandium is commonly done by solvent extraction using organophosphorus compounds. This process however produces a lot of waste extractants. To circumvent this challenge, a model organophosphorus compound phenylphosphinic acid (PPI) was immobilized to a polymer support fabric to produce a Sc(III) adsorbent for high throughput scandium recovery with less waste generation. Polymer support (PP‐g‐PGMA) for the organophosphorus compound was synthesized using radiation‐induced graft polymerization. Successful post‐polymer modification of the PGMA grafts to attach PPI groups was carried out using 1 M PPI in isopropanol at 80°C for 4 h, achieving a maximum functional group density of 1.32 mmol/g. The obtained PP‐g‐PGMA‐PPI fabrics were used in the batch Sc(III) adsorption experiments. The results showed that PP‐g‐PGMA‐PPI effectively adsorbed low concentrations of Sc(III) at a pH of at least 2.0. More than 98% adsorption was achieved using 1 ppm Sc(III). The synthesized adsorbent was also shown to be selective for Sc(III) even in the presence of Fe(III) and Al(III) ions. PP‐g‐PGMA‐PPI adsorbent fabrics are therefore promising alternatives to solvent extraction methods and ion‐exchange granular resin technologies in the recovery of scandium.
Air‐Stable Mn doped CuCl/CuO Hybrid Triquetrous Nanoarrays as Bifunctional Electrocatalysts for Overall Water Splitting
Authors: Chen Ying , Cai Zhengyang , Wang Ding , Yan Ya , Wang Ping , Wang Xianying
Published: September 2021

The development of highly efficient non‐precious metal catalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is key for large‐scale hydrogen evolution through water splitting technology. Here, we report an air‐stable Cu‐based nanostructure consisting of Mn doped CuCl and CuO (CuCl/CuO(Mn)‐NF) as a dual functional electrocatalyst for water splitting. CuCl is identified as the main active component, together with Mn doping and the synergistic effect between CuCl and CuO are found to make responsibility for the excellent OER and HER catalytic activity and stability. The assembled electrolyzes also exhibit decent water splitting performance. This work not only provides a simple method for preparing Cu‐based composite catalyst, but also demonstrates the great potential of Cu‐based non‐noble metal electrocatalysts for water splitting and other renewable energy conversion technologies.
Syntheses and Structures of trans‐bis(Alkenylacetylide) Ruthenium Complexes
Authors: Hall Michael R. , Moggach Stephen A. , Low Paul J.
Published: September 2021

A series of ruthenium alkenylacetylide complexes trans‐[Ru{C≡CC(=CH2)R}Cl(dppe)2] (R=Ph (1 a), cC4H3S (1 b), 4‐MeS‐C6H4 (1 c), 3,3‐dimethyl‐2,3‐dihydrobenzo[b]thiophene (DMBT) (1 d)) or trans‐[Ru{C≡C‐cC6H9}Cl(dppe)2] (1 e) were allowed to react with the corresponding propargylic alcohol HC≡CC(Me)R(OH) (R=Ph (A), cC4H3S (B), 4‐MeS‐C6H4 (C), DMBT (D) or HC≡C‐cC6H10(OH) (E) in the presence of TlBF4 and DBU to presumably give alkenylacetylide/allenylidene intermediates trans‐[Ru{C≡CC(=CH2)R}{C=C=C(Me)}(dppe)2]PF6 ([2]PF6). These complexes were not isolated but deprotonated to give the isolable bis(alkenylacetylide) complexes trans‐[Ru{C≡CC(=CH2)R}2(dppe)2] (R=Ph (3 a), cC4H3S (3 b), 4‐MeS‐C6H4 (3 c), DMBT (3 d)) and trans‐[Ru{C≡C‐cC6H9}2(dppe)2] (3 e). Analogous reactions of trans‐[Ru(CH3)2(dmpe)2], featuring the more electron‐donating 1,2‐bis(dimethylphosphino)ethane (dmpe) ancillary ligands, with the propargylic alcohols A or C and NH4PF6 in methanol allowed isolation of the intermediate mixed alkenylacetylide/allenylidene complexes trans‐[Ru{C≡CC(=CH2)R}{C=C=C(Me)}(dmpe)2]PF6 (R=Ph ([4 a]PF6), 4‐MeS‐C6H4 ([4 c]PF6). Deprotonation of [4 a]PF6 or [4 c]PF6 gave the symmetric bis(alkenylacetylide) complexes trans‐[Ru{C≡CC(=CH2)R}2(dmpe)2] (R=Ph (5 a), 4‐MeS‐C6H4 (5 c)), the first of their kind containing the dmpe ancillary ligand sphere. Attempts to isolate bis(allenylidene) complexes [Ru{C=C=C(Me)R}2(PP)2]2+ (PP=dppe, dmpe) from treatment of the bis(alkenylacetylide) species 3 or 5 with HBF4 ⋅ Et2O were ultimately unsuccessful.
Do investors care about carbon emissions under the European Environmental Policy?
Authors: Basse Mama Houdou , Mandaroux Rahel
Published: September 2021

We explore the extent to which cross‐sectional differences in carbon dioxide emissions matter for future valuations of European firms regulated under the European Union Trading Scheme (EU ETS). Counterintuitively, we find that firm‐level emissions share a robust concave relationship with future market valuations. Initially, market valuations increase in emissions potentially because emissions are considered essential for normal production processes; however, the valuation premium decreases and becomes negative beyond a threshold of emissions due to looming regulatory and transition risks. Firms in the lower quartile of emissions trade at an average premium of 2.42%, against a 20.78% discount in the upper quartile (the peak is 3.85%). Importantly, the concave relationship obtains only in smaller firms with lower analyst coverage and lower institutional ownership, and the predictive power of emissions is limited to firms with no reported investments in clean technology. Therefore, policymakers might consider promoting the development and diffusion of green technologies.
A prospective Phase III trial evaluating patient self‐reported pain and cosmesis in accelerated partial breast irradiation utilizing 3‐D versus intensity‐modulated radiotherapy
Authors: Leonard Charles E. , Wang Yunfei , Asmar Lina , Lei Rachel Y. , Howell Kathryn T. , Henkenberns Phyllis L. , Johnson Timothy K. , Hobart Tracy L. , Tole Shannon P. , Kercher Jane M. , Widner Jodi L. , Barke Lora , Kaske Terese , Carter Dennis L.
Published: September 2021

Purpose/Objective

The primary objective is to examine patient self‐assessment of breast pain and cosmesis between three‐dimensional (3D‐CRT) versus intensity‐modulated radiotherapy (IMRT). The secondary objective is to evaluate any relationship of treatment planning conformality of both cohorts to patient‐assessed pain. Assessments were performed at interim 12, 24, 36, and 48 months with a final 5‐year assessment.

Materials/Methods

In total, 656 patients (3D‐CRT n = 328; IMRT n = 328) were randomly assigned to either IMRT or 3D‐CRT accelerated partial breast radiotherapy to 38.5 Gy in 10 BID 3.85 Gy fractions.

Results

Median follow‐up was 3 years. Multivariate analysis showed that pain severity significantly decreased from baseline to the 12‐month follow‐up visit (<0.001 for both 3D‐CRT and IMRT) in each cohort. There was significantly less pain at 2 (p = 0.002) and 3 years (0.045) in the IMRT arm versus the 3D‐CRT arm when compared to the baseline pain level. There was no difference in patient‐assessed cosmesis at any follow‐up point; however, although MD‐assessed cosmesis showed no difference from years 1 to 4, there was significantly better cosmesis for 3D‐CRT versus IMRT (p = 0.047) at 5 years. There was a significant correlation between a maximum pain score and an increase in the CI100 (indicating less conformity) in the IMRT cohort (p < 0.01) and in the IMRT subgroup when the CI100 was ≤0.37 cohort arm (p = 0.01).

Conclusion

In the analysis of our primary objective we found that at 2 years, IMRT resulted in more interval improvement in breast pain after baseline when compared to patients treated with 3D‐CRT planning. As seen in our secondary analysis, this may be due to the ability of IMRT to achieve higher conformality (as evidenced by lower CI values) resulting in less fibrosis. There were no differences in patient‐assessed cosmesis or MD‐assessed cosmesis for years 1–4; however, physician‐assessed 5‐year cosmesis was better with 3D‐CRT.
Head to head comparison of quantitative flow ratio using 4‐French and 6‐French catheters versus fractional flow reserve
Authors: Cuenin Léo , Honton Benjamin , Aminfar Farhang , Meyer Pierre , Mariottini Claude , Haessler Maelle , Vareille Philippe , Wijns William , Maillard Luc , Adjedj Julien
Published: September 2021

Objectives

To validate QFR using 4‐F diagnostic catheters compared to using 6‐F guiding catheters, with conventional guidewire‐based FFR as the reference standard, using independent core laboratory analysis.

Background

Quantitative Flow Ratio (QFR) allows Fractional Flow Reserve (FFR) calculation based on the coronary angiogram, using 5‐ or 6‐French (F) catheters. However, the use of 4‐F diagnostic catheters to perform coronary angiography is currently routine in some centers.

Methods

We included all consecutive patients with stable coronary artery disease and indicated for physiological assessment. QFR was performed using a 4‐F diagnostic catheter, then QFR was performed using a 6‐F guiding catheter while conventional FFR was measured using a pressure guidewire. Angiograms were sent to two separate core laboratories.

Results

One hundred lesions in 67 consecutive patients with QFR performed using 4‐F and 6‐F catheters, and with conventional FFR, were included. Pearson's correlation coefficient was for QFR 4‐F vs. FFR 0.91 [0.87–0.94], for QFR 6‐F vs. FFR 0.90 [0.86–0.94], and for QFR 4‐F vs. QFR 6‐F 0.93 [0.90–0.95]. Receiver‐operator characteristic curves (ROC) comparing the ability to predict an FFR value above or below 0.80 with QFR 4‐F and 6‐F were generated. The area under the ROC curve (AUC) vs. FFR was 0.972 [0.95–0.99] for QFR 4‐F and 0.970 [0.94–0.99] for QFR 6‐F.

Conclusions

Our study demonstrated the feasibility of performing QFR analysis from angiograms obtained by 4‐F catheters, and showed a good correlation with QFR performed using 6‐F catheters as well as with conventional FFR performed using a pressure guidewire.
A Content Analysis of Qualitative Dissertations in Counselor Education
Authors: Waalkes Phillip , DeCino Daniel , Flynn Stephen V.
Published: September 2021

We conducted a qualitative content analysis on counseling dissertations (N= 250) completed between 2017 and 2018. Identified categories included (a) paradigms, philosophies of science, and theories; (b) research methodologies; and (c) trustworthiness. The results indicated an infrequent use of paradigmatic frameworks and a distinct pattern of trustworthiness strategies.
Update on the revision of Eurocode 3 – Evolution by improvement and harmonisation
Authors: Kuhlmann Ulrike , Schmidt‐Rasche Christina , Jörg Fabian , Spiegler Jennifer , Euler Mathias
Published: September 2021

This paper gives an overview on recent work regarding the revision of Eurocode 3 on European level including selected scientific and technical issues and a summary of the activities executed within the European Standardisation committee CEN/TC250/SC3 “Design of Steel Structures” under the chair of Prof. Dr.‐Ing. Ulrike Kuhlmann. This includes the description of current normative developments for the 2nd Generation of Eurocodes which aim at an evolution by improvements and harmonisation of the existing codes. In addition, a technical review of selected rules is given on a number of issues, which support the code revision and reflect well the recent tendencies in steel structures.
High Strength Steel and Fuse Dissipative Solutions for Seismic Resistant Building Structures
Authors: Dubina Dan
Published: September 2021

The robustness of structures against severe seismic action is ensured by their global performance, in terms of ductility stiffness and strength, properly calibrated. The “plastic“ members of ductile Mild Carbon Steel ‐ MCS – (S235 to S355) will dissipate the seismic energy, acting as “structural fuses“, while the “elastic“ members, must be provided of adequate overstrength, to have the capacity to carry the supplementary stresses after the plastic hinges have been formed and the redistribution forces were occurred. For these elastic members, High Strength Steels (HSS), such as S460 to S690, might be used, provide them the necessary overstrength, without enhancing the stiffness, because that could unbalance the structural system. These structures, which combine HSS with MCS, are termed Dual‐Steel (DS). The braced frames can be equipped with detachable dissipative MCS members, which are acting as seismic fuses. In case of CBF, the fuses might be the Buckling Restrained Braces (BRB), while for EBF, the links could take this role. In case of MRF, Steel Plate Shear Walls (SW) can be used as fuses. To make possibly to replace the used fuses, the HSS elastic part of the structure, has the mission to re‐centring the structure after the earthquake. This is the subject of present paper.
Enhanced Composite Behavior of CFST with Blind‐Bolted Connections under Tensile Pull‐out Tests
Authors: Debnath Partha Pratim , Chan Tak‐Ming
Published: September 2021

The structural behavior and efficiency of high strength hollo‐bolts for moment connections in square CFST are evaluated. Investigations are carried out numerically to assess the composite behavior and tensile pull‐out capacity of the bolts. FE models were developed for existing experimental specimens and validated to further carry out parametric studies. It is observed that though the presence of concrete in hollow steel tube can effectively reduce the overall deformation of the tube, there has been very little enhancement in strength and stiffness for a normal hollo‐bolted connection under tensile loading. Whereas, with an enhanced bolt embedment length has led to considerable increase in strength and stiffness of the connection. The head of the elongated bolt anchored into the concrete core has also been useful to use the tensile strength of the bolts thus effectively using the bolt capacity. It is also observed that, the failure modes of the extended hollo‐bolt connections can be altered from concrete cone failure to bolt necking to tube wall yielding or a combination of two of them as per the strength arrangement of the components. Several parametric studies based on bolt length, bolt grade, concrete grade, tube wall thickness has been investigated and failure modes have been reported.
A simplified analytical model for a T‐stub component with preloaded bolts
Authors: Bendjahene Chamseddine , Soltani Rabah , Mahdjouba Sadek
Published: September 2021

Endplate bolted joints are largely used in steel frames and have been the subject of many theoretical studies. The purpose of this work is to present an analytical model, which takes into account the bolt preloading effect on the axial behaviour of the tensile zone of an endplate bolted beam‐to‐column connection under increasing monotonous static loading. The article describes the necessary formulation used to evaluate the properties of the proposed analytical model. Specimens considered for the validation of the theoretical model reflect different geometries, strengths and preloading conditions of bolts. These prototypes were designed to undergo the collapse modes contained in Eurocode3. The analytical model permits to form trilinear and non‐linear load‐displacement curves covering elastic, plastic and ultimate domains. The load‐displacement curves of the theoretical model were compared with the experimental ones.
Fatigue life of preloaded injection bolts in a bridge strengthening scenario – sensitivity analysis of fatigue life estimators
Authors: Pedrosa Bruno , Rebelo Carlos , Correia José , Veljkovic Milan , da Silva Luís Simões
Published: September 2021

Old metallic bridges are prone to high levels of structural degradation due to their long service life, therefore, it is essential to study strengthening techniques. Implementation of injection bolts to replace riveted joints exposed to fatigue damages has been studied. The mechanical performance of injection bolts has been studied mainly based on quasi‐static or creep tests. The objective of this paper is comparison of fatigue resistance between bolted joints with preloaded injection bolts opposing bolted joints with preloaded high strength bolts. Specimens were defined aiming to reproduce as close as possible a strengthening scenario. Single and double lap joints were tested. The fatigue phenomenon has a stochastic nature and therefore robust models are necessary to estimate parameters of distribution functions. Therefore, different estimation methodologies were implemented to determine the parameters of Weibull distribution. The main goal was to define reliable S‐N design curves. Results showed that the use of preloaded injection bolts contribute to increase the fatigue life and to reduce the scatter, mainly for double lap joints. It is shown that S‐N curves of EN1993‐1‐9 do not represent the fatigue strength of structural details with old metallic materials.
Experimental Analyses on the Resistance of Tapped Blind Holes
Authors: Kraus Matthias , Klaus Martin , Wittor Björn
Published: September 2021

Bolted connections are commonly used in steel construction. The load‐bearing behavior of bolt fittings has extensively been studied in various research activities and the bearing capacity of bolted connections can be assessed well by standard regulations for practical applications. With regard to tensile loading, the nut does not have strong influence on resistances, since the failure occurs in the bolts due to higher material strengths of the nuts. In some applications, so‐called “blind holes” are used to connect plated components. In a manner of speaking, the nut is replaced by the “outer” plate with a prefabricated hole and thread, in which the bolt can be screwed and tightened. In such connections, the limit load capacity cannot solely be assessed by the bolt resistance, since the threaded hole in the base material has strong influence on the structural behavior. In this context, the available screw‐in depth of the blind hole is of fundamental importance. The German National Annex of EN 1993‐1‐8 provides information on a necessary depth in order to transfer the full tensile capacity of the bolt. However, some connections do not allow to fabricate such depths. In these cases, the capacity of the connection is unclear and not specified. In this paper, first experiments on corresponding connections with different screw‐in depths are presented and compared to limit load capacities according to the standard.
Duroplastic gap filling materials in preloaded bolted connections
Authors: Makevičius Lukas , Stranghöner Natalie , Kunde Carsten , Thelen Sebastian
Published: September 2021

In steel structures, bolted connections are preloaded either for load‐bearing capacity reasons or for serviceability reasons. Single and multi‐section connections of wind turbines, offshore plants, bridges etc. are typical application examples.

Gap formation due to production‐ and assembly‐related imperfections poses a risk for a controlled application of the required preload level, which is vital for slip‐resistant and fatigue loaded connections. Furthermore, it might significantly affect the desired behaviour of the connection or even lead to premature failure. For this reason, EN 1090‐2 provides regulations on the allowable gap formation and even prescribes measures to avoid negative outcomes. One of the possibilities for a gap compensation are gap filling materials, also known as liquid shim or load transfer materials, such as MM1018 of DIAMANT Metallplastic GmbH, Germany, a two‐component composite system filled with special metallic materials.

Currently, systematic investigations into the application of duroplastic gap filling materials in preloaded bolted connections are carried out in the frame of the German cooperation project “Bri‐San‐T ‐ DuroFüllSta”. Herein, the slip factor is experimentally determined according to EN 1090 2, Annex G under variation of application type, gap thickness, curing time, temperature and surface condition. Furthermore, relaxation tests are carried out to determine possible preload losses over the intended service life of the structure.

The presented contribution intends to provide an insight into the main properties of duroplastic gap filling materials with regard to their application in preloaded bolted connections under various conditions.
Greece's new high‐speed railway line: Detailed design and construction engineering of bridge SG26
Authors: Mavrakis Georgios
Published: September 2021

The paper presents the several aspects of the detailed design and the construction engineering procedure of the most important Railway Bridge of the New Double High‐Speed Railway Line connecting Athens and Thessaloniki, the two biggest cities in Greece. The total length of the bridge is 404.8m consisting of three simply supported tied arches with a width of 18.03m. The two piers, 45.5m height each, are supported on rigid caisson foundations. The bridge has been constructed using the incremental launching method due to the deep valley below. The special characteristic of the bridge is that it crosses an active fault zone, associated with large seismic events (e.g. 1954 magnitude 6.8). Seismic devices (Friction Pendulum System and Fluid Viscous Damper) are installed between the deck and the substructure in order to absorb the anticipated seismic energy and consequently reduce deck displacement and force transmission to the structural elements. I. MAVRAKIS & PARTNERS S.A. carried out the detailed design and construction engineering, including the design of the temporary steel piers, the incremental launching procedure, the precamber design of the arches, the prestressing sequence of the hangers, the seismic isolation design and the shop drawings of the whole structure.
Influence on the buckling behaviour from imperfections of different launching bearings
Authors: Maier Nadine , Mensinger Martin , Ndogmo Joseph , Tallushi Enea
Published: September 2021

In general, today two types of launching bearings are used in the construction of large steel and steel concrete composite bridges. These are sliding rockers and systems with hydraulic bearings. During incremental launching, the center of the webs of the superstructure is not perfectly in line with the center of the launching bearings due to unavoidable tolerances. In contrast to sliding rockers, the hydraulic bearings are not supported linearly in the transverse direction and the buckling behaviour may be affected by eccentricities. There is currently no scientific explanation for this assumption. The advantages and disadvantages of the respective systems are under discussion. At the Technical University, large‐scale buckling tests were carried out on longitudinally stiffened plates under biaxial stresses with different launching bearings and eccentric load introduction. In this paper we present the test results and discuss the advantages and disadvantages of the respective systems. Based on the experimental results, a numerical model was validated. The test results as well as the results from the validated numerical model will show the influence on the buckling behaviour from the respective launching bearings.
Damage to transmission towers under thunderstorm winds
Authors: Calotescu Ileana , Bîrsan Marius
Published: September 2021

A thunderstorm downburst, as defined by Fujita (1985) is “a strong downdraft which induces an outburst of damaging winds on or near the ground”. The vertical profile of wind velocities associated with downburst winds are substantially different than those corresponding to the traditional boundary layer vertical profile. In case of thunderstorms, the wind velocity does not increase with height as in the case of synoptic winds but rather maximum values are found around 50m up to 100m and thus inducing larger responses of low‐rise and mid‐rise buildings such as, for example transmission towers. These are structures of extreme ecconomic importance for any country as their damage may affect a considerable number of people. This paper presents a review of damage caused by recent thunderstorm winds to transmission towers in Romania. The date, location and intensity of thunderstorms were identified based on a vast online research of massmedia reports documenting strong wind events and associated damage between 2013 and 2017. Events that have produced partial damage or total collapse to transmission towers are described in detail. Measured wind data provided by the National Meteorological Administration from meteorological stations nearby the location of damage for each event are provided.
Mechanical Behavior of Steel Bridge Deformed by Collision
Authors: Yamaguchi Eiki , Amamoto Takuya
Published: September 2021

A bridge over a highway is damaged by a truck running underneath occasionally. Typical collision damages observed in a steel girder bridge are as follows: a lower flange is deformed in the vertical direction and/or in the horizontal direction; a web plate is bent; a transverse stiffener is buckled; and a transverse stiffener is partly separated from the web. The influence of the damage on the safety of the bridge has to be judged right away. Nevertheless, it is not an easy task, since the mechanical behavior of a deformed girder has not been studied well. The first author has been involved in the evaluation of a steel girder bridge damaged by collision. Based on the data obtained from this bridge, the mechanical behavior of the deformed girder is studied numerically in the present study. To be specific, the deformation of the main girder due to collision is reproduced by the finite element analysis and the deformed steel girder is loaded to investigate its mechanical behavior. The result indicates that the damage influences the mechanical behavior of the girder, yet as far as the damage is confined to the deformation of the girder, the collision does not threaten the safety of the bridge even when the deformation is quite large. It is also clarified that the influence is mostly attributable to the configuration change and that the residual stress plays a relatively small role.
Cable structure design of suspension bridges through strand reduction method
Authors: Acun Acuner
Published: September 2021

Cable structures hold a special place for the cost of suspension bridges. Considerable development of the structural cable material leads to design and construction of long‐span suspension bridges. Thus, designing cable structures that are cost‐effective and reliable is significant for these mega structures. The overall layout of a main cable is consistent with constant number of elements per span since the design of the first suspension bridge. However, the reduction of main cable area in regard to design loads could play an important role in saving cost of long span suspension bridges. This paper presents the strand reduction approach for the cable structure design of suspension bridges. The proposed approach has been implemented by releasing the required number of parallel wire strands in main cable of the suspension bridge at specific locations in accordance with axial loads on main and hanger cables where released strands are transformed into a hanger cable with special types of clamps. The strand reduction approach is named as “saddle‐clamp system” and has been compared with the current design of 1915 Canakkale Bridge. The results indicate that the strand reduction method provides 7.6% to 34.1% material quantity deduction for the cable structures of the suspension bridge.
Design of stiffened plates subjected to axial compression and transverse load
Authors: Kleppe Svein‐Rune , Aalberg Arne , Eltvik Liv
Published: September 2021

Stiffened plates (orthotropic plates) are used in many structures, for instance as plate girders and box girders in bridges, in ship hulls, and in bridge decks to minimize the dead load. Used as flanges or part of flanges in larger cross‐sections, stiffened plates develop membrane compression or tension, and in some cases in‐plane shear due to bending or axial actions on the cross‐section. The strength analysis of an orthotropic bridge deck has to take into account both buckling of the stiffened plate as a unit, local buckling of subpanels of the deck plate or the stiffeners, stiffener instability, and effects of transverse loading (e.g. dead load plus traffic load) on the stiffened plate.

Adequate rules to determine the capacity of stiffened plates subjected to the combination of axial force and transverse load, as in bridge decks, are scarce or non‐existing in the present Eurocodes for design of stiffened plates and should be developed. An approach applying detailed FE‐analyses will often not be feasible in practical design due to an often weak correlation between the various loads, e.g. dead load, traffic load and loading in horizontal direction (wind), a large number of loading patterns for moving loads, different load combinations and loading levels in adjacent spans, as well as many different cross sections along the bridge.

As a pre‐study of the mentioned load combination of axial force and transverse loading it have been simulated a stiffened plate (4 by 5 meter) motivated by the orthotropic deck of a bridge box girder for a suspension bridge. The axial stress was varied from 0 N/mm2 to 250 N/mm2 and combined with application of transverse loading until the stiffened plate collapsed in a flexural buckling mode. The capacity was determined following the provisions in Eurocodes prEN 1993‐1‐1, EN 1993‐1‐5, EN 1993‐1‐7 and the offshore standard DNV‐RP‐C201.

It is evident that the modeled typical bridge deck, which is much wider than it is long and has large longitudinal stiffeners, behaves like a beam‐column between the supports. Even if the modeled stiffened plate is made almost quadratic, column‐like behavior prevails, and plate‐like behavior can be neglected.

Capacity checks of a stiffened bridge deck, considering a strip of the deck comprising plate and one belonging stiffener, involve a highly mono‐symmetric cross‐section. Capacity should consider yielding both at the plate side and at the stiffener side. The DNV standard does this, and capacity determined from its equations agrees quite well with the FE‐simulations. The design provisions in the new prEN 1993‐1‐1 (Appendix C), which refer to its ordinary beam‐column formulas, must be modified to account for yielding at both sides of the stiffened deck to produce accurate results over the entire range of axial compression and transverse load. When modified, capacity predictions are on the safe side, yielding capacity approximately 70 % of the FE‐predictions.
Development of a transition piece for a self‐erecting wind energy plant
Authors: Korte Sebastian , Pak Daniel , Friehe Mirko , Fontecha Robert , Feldmann Markus , Reese Christian , Schmitz Katharina
Published: September 2021

For the construction of wind towers with large hub heights up to 200m, the FOSTA research project P1392 HYTOWER [1] investigated a concept for a self‐erecting wind energy plant with steel‐steel hybrid tower. A tubular steel tower is lifted inside a lattice tower using a strand lifting system. During this process the tubular steel tower is stabilized by hydraulic cylinders. A specially developed transition piece is used to accommodate the lifting system during the lifting process and to finally connect the two tower parts. In this paper, the erection process as well as the development of the transition piece is presented.
Numerical models for the analysis of shear walls in light steel residential buildings
Authors: Baldassino Nadia , Zandonini Riccardo , Zordan Marco
Published: September 2021

In recent years, the use of steel light housing structural solutions made of cold‐formed thin‐walled profiles (CFS) is becoming increasingly popular. Lightness, high structural efficiency, durability, rapidity and simplicity of erection of the building and its finishes are some of the main advantages of these systems, which make them attractive and competitive with respect to more traditional constructional solutions. In these buildings, which do have a skeleton made of cold‐formed steel profiles completed by sheathings made of various materials, the key role of transmission of both vertical and horizontal loads from the floors to the foundation, is played by the shear walls. Recently, the University of Trento carried out a project aimed to develop an industrialized housing system made of CFS members. In this framework, experimental and numerical studies of the in‐plane lateral response of shear walls were performed. In particular, this paper summarizes first the experimental program and then it focuses on the main features of numerical models and on their validation in both monotonic and cyclic regime. The critical parameters governing the response of these complex systems are finally identified and discussed.
Study of the shear behaviour of floor diaphragms in light steel residential buildings
Authors: Baldassino Nadia , Zandonini Riccardo , Zordan Marco
Published: September 2021

Steel housing solutions made of thin‐walled cold‐formed profiles (CFS) appear to be very competitive in seismic areas due to their lightweight and the associated reduced mass. This non‐negligible advantage associated with the competitive costs and the ease of erection made popular this type of building solution. Aimed at investigating the potential of these structural systems, in recent years, several extensive studies of the lateral response of shear walls were carried out. On the contrary, little attention was paid to the behavior of the floor diaphragms and on their contribution to the overall building response. The University of Trento, in the framework of a wider research project aimed at the development of a residential building system made of CFS profiles, investigated the response of CFS floor systems subjected to in plane shear loading. Four types of floors characterized by two different beams systems and two different types of deck were tested in both monotonic and cyclic regime. Experimental results enabled the calibration of FE models simulating both the floor components and the whole floors. In this paper, the main features and outcomes of the tests and of the numerical analyses are presented and discussed.
Contribution of OSB Sheathing to Racking Capacity of Cold‐Formed Steel Frames
Authors: Kechidi Smail , Banks Nigel , Iuorio Ornella
Published: September 2021

In recent years, new innovative systems to ensure high structural and environmental performance have emerged in constructional steel practice. Among others, modular construction using cold‐formed steel (CFS) frames which offer some advantages over conventional structural system counterparts, such as high strength‐to‐weight ratio, controlled material quality and sustainability. Wood‐sheathed shear wall is one of the lateral load resisting systems adopted in CFS modular construction. It is composed of CFS C‐shaped framing members (chord studs, studs and tracks) attached to wood sheathing using fasteners. The resistance capacity of these shear walls, when subjected to in‐plan lateral loads, is governed by the connections between the frame and the sheathing board. It is therefore crucial to quantify the shear capacity of sheathing‐to‐frame fasteners. In this context, a testing rig was developed consisting of two CFS lipped channels facing back‐to‐back connected on the flanges by oriented strand board (OSB) and loaded such that the 8 connecting fasteners experience shear. The prevailing role of sheathing thickness and fastener type is highlighted in the results. The experimental results are summarized for further use in the analysis of shear walls under lateral load.
Numerical Modelling and Optimisation of Cold‐Formed Steel Purlins
Authors: Almatrafi Meshal , Theofanous Marios , Dirar Samir , Bock Marina
Published: September 2021

This paper reports a numerical study on the optimization of the lip size of Z‐sections under gravity loads. Numerical models simulating the structural response of cold‐formed steel Z purlins partially restrained by cladding and angle struts and subjected to sagging moment were developed and validated against a total of nine previously reported experimental results on Z‐sections that failed in local or/and distortional buckling. Models of varying levels of complexity were generated and the key parameters affecting the structural response were determined by means of a sensitivity analysis. The investigated parameters included the magnitude, shape and combination of initial geometric imperfections pertinent to local and distortional buckling and the simplified or explicit modelling of test details such as struts and sheeting. Having determined the appropriate modelling strategy that yields the best balance between accuracy and computational cost, parametric studies were conducted to investigate the effect of decreasing or increasing the lip depth on the sections' moment resistance and corresponding failure mode. Based on the parametric study results, the optimal lip size which maximizes the moment/weight ratio for each section was determined.
Constrained finite element method with displacement mapping
Authors: Hoang Trung , Adany Sandor
Published: September 2021

A widely used approach to understand and analyze the complex behavior of a structural member is to decompose the complex phenomenon into simpler ones, and then to interpret the complex phenomenon as the superposition of the simpler ones. Accordingly, the deformations of thin‐walled members are frequently decomposed into global, distortional, local‐plate, etc. modes. One well known practical technique is the constraining of shell models; the idea first appeared in the constrained finite strip method, then later in the constrained finite element method, or cFEM in short. While the cFEM was proved to be applicable for a wide range of problems, its disadvantage is that it requires a specific rectangular shell finite element. The aim of the reported research is to release the limits set by this specific shell element. The idea is to use two discretizations and two corresponding basis function systems. One is based on an ordinary shell finite element, the other one is on the cFEM shell elements. The basis functions of the cFEM are mapped to the ordinary shell model, then the calculations are completed in the ordinary shell model but with using the cFEM basis functions. In the paper the proposed method is briefly introduced and some proof‐of‐concept examples are presented.
Optimized Design of Cold‐Formed Steel Elements for Serviceability and Ultimate Limit States
Authors: Mojtabaei Seyed Mohammad , Hajirasouliha Iman , Becque Jurgen
Published: September 2021

Cold‐formed steel (CFS) sections are gaining ever increasing popularity in modern construction practice due to their advantages, such as efficient material use and sustainability. While the manufacturing flexibility of CFS cross‐sectional shapes brings innovative and complex shapes within practical reach, obtaining optimum design solutions can be a challenging task due to the complex mechanical behaviour of CFS elements, which is controlled by local, distortional and global buckling modes, as well as the need to account for manufacturing and end‐use constraints. This study presents a practical framework for the development of optimised CFS beam sections with maximum flexural strength and minimum deflections in ultimate and serviceability limit state conditions, respectively, in accordance with Eurocode 3 (EC3). A population‐based Genetic Algorithm optimisation method is employed to obtain optimum solutions for ten different CFS cross‐section prototypes, while the EC3 geometric restrictions and a number of manufacturing and end‐use constrains are also considered. It is shown that sections optimised based on serviceability limit state (SLS) and ultimate limit state (ULS) requirements can provide up to 44% higher effective stiffness and 55% higher bending moment capacity, respectively, compared to standard commercial lipped channel sections with the same amount of material. The results also indicate that using optimised plain channels and folded‐flange sections generally leads to the best design solution in SLS and ULS optimization, respectively.