bluuebunny/crossref_metadata_2025 huggingface dataset:
Multibridge VO2‐Based Resistive Switching Devices in a Two‐Terminal Configuration
Authors: Gao Xing , Roskamp Thijs J. , Swoboda Timm , Rosário Carlos M. M. , Smink Sander , Muñoz Rojo Miguel , Hilgenkamp Hans
Published: September 2023

Vanadium dioxide exhibits a hysteretic insulator‐to‐metal transition (IMT) near room temperature, forming the foundation for various forms of resistive switching devices. Usually, these are realized in the form of two‐terminal bridge‐like structures. The authors show here that by incorporating multiple, parallel VO2 bridges in a single two‐terminal device, a wider range of possible characteristics can be obtained, including a manifold of addressable resistance states. Different device configurations are studied, in which the number of bridges, the bridge dimensions, and the interbridge distances are varied. The switching characteristics of the multibridge devices are influenced by the thermal cross‐talk between the bridges. Scanning thermal microscopy (SThM) is used to image the current distributions at various voltage/current bias conditions. This work presents a route to realize devices exhibiting highly nonlinear, multistate current–voltage characteristics, with potential applications in, e.g., tunable electronic components and novel, neuromorphic information processing circuitry.
FeCl3 ⋅ 6H2O Mediated Sequential Oxidative Cleavage and Spiro Coupling of Peroxyoxindole with Cyclic‐1,3‐diketone/1‐Naphthol for the Synthesis of Spirooxindolo‐Xanthene Derivatives
Authors: Londhe Gokul S. , Gnanaprakasam Boopathy
Published: September 2023

Herein, an efficient approach to synthesize various hexahydro‐1H‐xanthene‐1,8‐dione or dibenzo xanthene containing bioactive spirooxindole derivatives is reported by using FeCl3 ⋅ 6H2O mediated spiro coupling of 1,3‐diketone or naphthalene‐1‐ol with peroxyoxindole. This new approach proceeds via a sequential oxidative cleavage of the C−C bond of peroxyoxindoles to generate the isatin intermediate and further reaction with two molecules of cyclic‐1,3 diketones through a series of reactions such as Knoevenagel condensation, Michael addition, and dehydration in one‐pot conditions. Furthermore, this sequential reaction of peroxyoxindole with malononitrile afforded 2‐(2‐oxoindolin‐3‐ylidene)malononitriles in very good yields in the presence of the most abundant Fe‐catalyst. A plausible mechanistic pathway in this transformation has been supported with experimental evidence and control experiments.
The intersection of social determinants of health and family care of people living with Alzheimer's disease and related dementias: A public health opportunity
Authors: Gaugler Joseph E. , Borson Soo , Epps Fayron , Shih Regina A. , Parker Lauren J. , McGuire Lisa C.
Published: September 2023

In this Perspective article, we highlight current research to illustrate the intersection of social determinants of health (SDOHs) and Alzheimer's disease and related dementia (ADRD) caregiving. We then outline how public health can support ADRD family caregivers in the United States. Emerging research suggests that family care for persons with ADRD is influenced by SDOHs. Public health actions that address these intersections such as improved surveillance and identification of ADRD caregivers; building and enhancing community partnerships; advancing dementia‐capable health care and related payment incentives; and reducing the stigma of dementia and ADRD caregiving can potentially enhance the health and well‐being of dementia caregivers. By engaging in one or all of these actions, public health practitioners could more effectively address the myriad of challenges facing ADRD caregivers most at risk for emotional, social, financial, psychological, and health disruption.
The Alzheimer's Disease Neuroimaging Initiative in the era of Alzheimer's disease treatment: A review of ADNI studies from 2021 to 2022
Authors: Veitch Dallas P. , Weiner Michael W. , Miller Melanie , Aisen Paul S. , Ashford Miriam A. , Beckett Laurel A. , Green Robert C. , Harvey Danielle , Jack Clifford R. , Jagust William , Landau Susan M. , Morris John C. , Nho Kwangsik T. , Nosheny Rachel , Okonkwo Ozioma , Perrin Richard J. , Petersen Ronald C. , Rivera Mindt Monica , Saykin Andrew , Shaw Leslie M. , Toga Arthur W. , Tosun Duygu ,   for the Alzheimer's Disease Neuroimaging Initiative
Published: September 2023

The Alzheimer's Disease Neuroimaging Initiative (ADNI) aims to improve Alzheimer's disease (AD) clinical trials. Since 2006, ADNI has shared clinical, neuroimaging, and cognitive data, and biofluid samples. We used conventional search methods to identify 1459 publications from 2021 to 2022 using ADNI data/samples and reviewed 291 impactful studies. This review details how ADNI studies improved disease progression understanding and clinical trial efficiency. Advances in subject selection, detection of treatment effects, harmonization, and modeling improved clinical trials and plasma biomarkers like phosphorylated tau showed promise for clinical use. Biomarkers of amyloid beta, tau, neurodegeneration, inflammation, and others were prognostic with individualized prediction algorithms available online. Studies supported the amyloid cascade, emphasized the importance of neuroinflammation, and detailed widespread heterogeneity in disease, linked to genetic and vascular risk, co‐pathologies, sex, and resilience. Biological subtypes were consistently observed. Generalizability of ADNI results is limited by lack of cohort diversity, an issue ADNI‐4 aims to address by enrolling a diverse cohort.
Awake rabbit model of ischemic spinal cord injury with delayed paraplegia: The role of ambient temperature
Authors: Yang Wang , Wu Qian‐qian , Yang Lu , Chen Yu‐jie , Jiang Ren‐qing , Zou Ling , Liu Qing‐shan , Shi Guang‐you , Cao Jiang , Yang Xiao‐chao , Sun Jian
Published: September 2023

Background

Paraplegia after spinal cord ischemia is a devastating condition in the clinic. Here, we develop an awake rabbit model of spinal cord ischemia with delayed paraplegia and explore the influence of ambient temperature on the outcomes after injury.

Methods

A total of 47 male rabbits were involved in the present study. Transient spinal cord ischemia was induced by occluding the infrarenal abdominal aorta of awake rabbits at different ambient temperatures. To find the optimal conditions for developing delayed paraplegia, hindlimb motor function after ischemia was evaluated between experiments.

Results

The onset and magnitude of ischemic injury varied with the ambient temperature maintained during the peri‐ischemia period. More serious spinal cord injury occurred when ischemia was induced at higher temperatures. At 18°C, 25‐minute ischemia resulted in 74% of rabbits developing delayed paraplegia. At a temperature of 28°C or higher, most of the animals developed acute paraplegia immediately. While at 13°C, rabbits usually regained normal motor function without paraplegia.

Conclusion

This awake rabbit model is highly reproducible and will be helpful in future studies of delayed paraplegia after spinal cord ischemia. The ambient temperature must be considered while using this model during investigation of therapeutic interventions.
Merging Manganese and Iminium Catalysis: Selective Hydroalkenylation of Unsaturated Aldehydes and Ketones
Authors: Zhao Chuan‐Gang , Du Chaoyu , Guo Zhenyu , Li Weipeng , Han Jie , Xie Jin
Published: September 2023

The use of synergistic catalytic strategy can usually circumvent the intrinsic limitations of one catalytic system. In this communication, we disclose a cooperative catalysis strategy of manganese and iminium catalysis to realize selective hydroalkenylation of unsaturated aldehydes and ketones. Its success stems from the LUMO activation of unsaturated carbonyl compounds with secondary amines as the organocatalyst and the synergistic HOMO activation of alkenylboronic acids with Mn2(CO)8Br2. This protocol exhibits several synthetic advances, e.g., simple operation, good functional group compatibility and good regioselectivity. The theoretical calculation indicates the migratory insertion followed by demetallation‐isomerization process is kinetically more favorable than Michael‐like nucleophilic addition. The use of proline‐derived organocatalyst can deliver the desired products in moderate enantioselectivity.
Distinct Selectivity Control in Solar‐Driven Bio‐Based α‐Hydroxyl Acid Conversion: A Comparison of Pt Nanoparticles and Atomically Dispersed Pt on CdS
Authors: You Yong , Han Peijie , Song Song , Luo Wei , Zhao Shengnan , Han Kaijie , Tian Ye , Yan Ning , Li Xingang
Published: September 2023

Solar‐driven photocatalytic lignocellulose conversion is a promising strategy for the sustainable production of high‐value chemicals, but selectivity control remains a challenging goal in this field. Here, we report efficient and selective conversion of lignocellulose‐derived α‐hydroxyl acids to tartaric acid derivatives, α‐keto acids, and H2 using Pt‐modified CdS catalysts. Pt nanoparticles on CdS selectively produce tartaric acid derivatives via C−C coupling, while atomically dispersed Pt on CdS switches product selectivity to the oxidation reaction to produce α‐keto acids. The atomically dispersed Pt species stabilized by Pt−S bonds promote the activation of the hydroxyl group and thus switch product selectivity from tartaric acid derivatives to α‐keto acids. A broad range of lignocellulose‐derived α‐hydroxyl acids was applied for preparing the corresponding tartaric acid derivatives and α‐keto acids over the two Pt‐modified CdS catalysts. This work highlights the unique performance of metal sulfides in coupling reactions and demonstrates a strategy for rationally tuning product selectivity by engineering the interaction between metal sulfide and cocatalyst.
Construction of Negative Electrostatic Pore Environments in a Scalable, Stable and Low‐Cost Metal‐organic Framework for One‐Step Ethylene Purification from Ternary Mixtures
Authors: Wen Hui‐Min , Yu Chenyi , Liu Miaoyu , Lin Chenyan , Zhao Beiyu , Wu Hui , Zhou Wei , Chen Banglin , Hu Jun
Published: September 2023

One‐step separation of C2H4 from ternary C2 mixtures by physisorbents remains a challenge to combine excellent separation performance with high stability, low cost, and easy scalability for industrial applications. Herein, we report a strategy of constructing negative electrostatic pore environments in a stable, low‐cost, and easily scaled‐up aluminum MOF (MOF‐303) for efficient one‐step C2H2/C2H6/C2H4 separation. This material exhibits not only record high C2H2 and C2H6 uptakes, but also top‐tier C2H2/C2H4 and C2H6/C2H4 selectivities at ambient conditions. Theoretical calculations combined with in situ infrared spectroscopy indicate that multiple N/O sites on pore channels can build a negative electro‐environment to provide stronger interactions with C2H2 and C2H6 over C2H4. Breakthrough experiments confirm its exceptional separation performance for ternary mixtures, affording one of the highest C2H4 productivity of 1.35 mmol g−1. This material is highly stable and can be easily synthesized at kilogram‐scale from cheap raw materials using a water‐based green synthesis. The benchmark combination of excellent separation properties with high stability and low cost in scalable MOF‐303 has unlocked its great potential in this challenging industrial separation.
Degradation behavior of polylactic‐co‐glycolic acid and polycaprolactone with nanosilver scaffolds
Authors: Dou Dandan , Zhang Yang , Zhou Jin , Li Linhao , Wang Lizhen
Published: September 2023

Ureteral stents are commonly used in clinical treatment of ureteral diseases. There were a series of complications, such as biofilms and crusts caused by bacteria after surgery. Therefore, biodegradable with bacteriostatic ureteral scaffolds would be the potential to solve above mentioned problems. In this study, nanosilver (AgNP) was added to the polylactic‐co‐glycolic acid (PLGA) and polycaprolactone (PCL) to prepare biodegradable antibacterial ureteral scaffold samples by 3D printing. The biocompatibility, antibacterial properties, degradability, and mechanical properties of samples were observed. The samples were under a strong inhibitory effect on both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), and the higher the concentration of AgNP, the stronger the antibacterial effect. When the concentration of AgNP was 10%, the antibacterial effect was up to 100%. AgNP was released continually with the degradation of samples, which can achieve a continuous antibacterial effect. The breaking strength of the samples without and with AgNP were 6.08 ± 1.16 MPa and 26.02 ± 2.00 MPa. The mechanical properties of samples with AgNP were higher than those without AgNP. It provides a potential way to design ureteral scaffolds based on biodegradable polymers with AgNP in the clinic.
First estimate of distribution, abundance, and risk of encounter with aquaculture vessels for the rare Chilean dolphin in the entire Northern Chilean Patagonia
Authors: Bedriñana‐Romano Luis , Viddi Francisco A. , Artal Osvaldo , Pinilla Elías , Hucke‐Gaete Rodrigo
Published: September 2023

Assessing distribution and abundance patterns for rare species is challenging yet imperative, considering the extant, potentially hazardous, anthropogenic activities. In particular, the poorly studied Chilean dolphin (Cephalorhynchus eutropia) exhibits an extremely patchy distribution and low densities, co‐occurring with the intensive aquaculture industry in Southern Chile, among other anthropogenic activities.

The distribution and abundance patterns of Chilean dolphins were assessed in the entire Northern Chilean Patagonia. A hierarchical species distribution model was fitted to data from line transect surveys using distance sampling techniques and environmental variables derived from topographic features and oceanographic models. A second version of this model used a joint‐likelihood approach to incorporate presence–pseudoabsence data for improving parameter estimation. Spatial predictions arising from these models were used to evaluate the relative probability of a dolphin encountering vessels from the local, predominantly aquaculture fleet.

The results show that using a joint‐likelihood approach drastically reduced uncertainty in the parameters controlling the effect of covariates and in the total abundance estimates. This model estimated an overall low abundance (median 2,225.8; 95% CI 1,340–3,867) for this species in the region, and indicates their preference for shallow, sheltered bays and inner channels, near river mouths, where low salinity is expected. The highest probabilities of dolphin–vessel interactions were found on the eastern coast of Chiloe Big Island, coinciding with the largest number of aquaculture concessions in the area.

Considering that the overall population of the Chilean dolphin is expected to be in the low thousands, that suitable habitat for the species is highly restricted, and that the species is facing increasing anthropogenic impacts, with some areas undergoing or planning major expansions in development, the results provided here should be considered in management plans for extant marine protected areas, and in the evaluation of current International Union for Conservation of Nature (IUCN) and national conservation categories for the species.
Membership function‐dependent predictive control for interval type‐2 Takagi–Sugeno fuzzy system
Authors: Zheng Hua , Zou Yuanyuan , Li Shaoyuan
Published: September 2023

In this paper, the problem of membership function‐dependent model predictive control (MFD‐MPC) of interval type‐2 Takagi–Sugeno (IT2 T‐S) fuzzy system is investigated. An online MFD‐MPC optimization problem is formulated to minimize an infinite horizon objective function subject to hard constraints on control input and system state. By using the variable dimension expansion method and dividing the operation domain of independent variables into several subdomains, a subregion‐based state feedback model predictive controller that offers more design flexibility is designed to stabilize the open‐loop fuzzy system. Based on descriptor system theory, the variable mismatching phenomenon between MFs and the coupling between plant, controller, and Lyapunov matrix are eliminated. Then, using the piecewise linear approximation technology, MFD sufficient conditions of low conservatism on guaranteeing recursive feasibility and the stability of IT2 closed‐loop fuzzy system are deduced by tightening terminal constraint set. Finally, a numerical example is provided to further explain the advance of the proposed method.
Nonlinear control strategies with maximum power point tracking for hybrid renewable energy conversion systems
Authors: Mansouri Adil , El Magri Abdelmounime , Lajouad Rachid , Giri Fouad , Watil Aziz
Published: September 2023

This paper addresses the problem of controlling and optimizing a hybrid renewable energy system, specifically consisting of a photovoltaic (PV) generator and a wind energy conversion system comprising a wind turbine and a permanent magnet synchronous machine. The primary control objectives involve maximizing power extraction from both the PV and wind turbine while ensuring efficient injection of the extracted energy into the electrical network and maintaining a suitable power factor. This study presents two key innovations that distinguish it from existing research. Firstly, it introduces a new hybrid PV/aerogenerator energy source that eliminates the need for a DC/DC converter in the PV structure. Secondly, unlike previous works that rely on various measurements such as wind speed, temperature, and irradiance, our approach only requires measurements of electrical variables. This advancement significantly reduces the number of sensors required and enhances the overall reliability of the system.
Measuring flexibility in autistic adults: Exploring the factor structure of the flexibility scale self report
Authors: Hollocks Matthew J. , McQuaid Goldie A. , Yerys Benjamin E. , Strang John F. , Anthony Laura G. , Kenworthy Lauren , Lee Nancy R. , Wallace Gregory L.
Published: September 2023

Cognitive flexibility differences are common for autistic individuals and have an impact on a range of clinical outcomes. However, there is currently a lack of well validated measurement tools to assess flexibility in adulthood. The Flexibility Scale was originally designed as a parent‐report measure of real‐world flexibility challenges in youth. The original Flexibility Scale provides a total score and five subscales: Routines and Rituals, Transitions and Change, Special Interests, Social Flexibility, and Generativity. In this study, we evaluate the factorial validity of the Flexibility Scale as a self‐report (Flexibility Scale Self Report) measure of cognitive flexibility, adapted from the original Flexibility Scale, for use by autistic adults. This study includes both a primary sample (n = 813; mean age = 40.3; 59% female) and an independently recruited replication sample (n = 120; mean age = 32.8; 74% female) of individuals who completed the Flexibility Scale Self Report. The analysis consisted of an initial confirmatory factor analysis (CFA) of the original Flexibility Scale structure, followed by exploratory factor analysis (EFA) and factor optimization within a structural equation modeling framework to identify the optimal structure for the questionnaire in adults. The identified structure was then replicated through CFA in the replication sample. Our results indicate an alternative optimal scale structure from the original Flexibility Scale, which includes fewer items, and only three (Routines/Rituals, Transitions and Change, Special Interests) of the five subscales contributing to the flexibility total score. Comparisons revealed no structural differences within the scale based on sex assigned at birth. Here the Generativity and Social Flexibility scales are treated as independent but related scales. The implications for measurement of cognitive flexibility in clinical and research settings, as well as theoretical underpinnings are discussed.
Stress and well‐being in autistic adults: Exploring the moderating role of coping
Authors: Muniandy Melanie , Richdale Amanda L. , Lawson Lauren P.
Published: September 2023

The wider stress literature points to negative associations between stress and well‐being. Similarly, the use of engagement coping strategies and disengagement coping strategies in the face of stress are related to improved and reduced well‐being respectively. However, in the autistic population stress and coping research is limited to date, and the extent to which coping may moderate the relationship between stress and well‐being is not known. Using data from an Australian online study, we explored the potential moderating (i.e. buffering or exacerbating) role of coping in the relationship between stress and well‐being in a sample of autistic adults (N = 86). Our findings indicated that increased stress was associated with lower well‐being. Further, moderation analyses showed that while both engagement coping (e.g. problem solving, positive appraisal) and disengagement coping (e.g., self‐distraction, being in denial) strategies had significant positive and negative direct effects on well‐being respectively; engagement coping also moderated the relationship between stress and well‐being, buffering the impact of stress on well‐being. Our results illustrate the different underlying mechanisms by which coping strategies may be associated with stress and well‐being. They also highlight the potential protective role of engagement coping strategies, which can be incorporated into the promotion and maintenance of well‐being in autistic adults.
Firms' sustainability engagement and sustainability‐related controversies
Authors: Kotzian Peter
Published: September 2023

Sustainability issues became ever more important for firms' business strategies. Not living up to public and stakeholders' expectations results in controversies damaging the firm's reputation. Firms integrate sustainability aspects – environmental, social, and governance (ESG) issues – in their business strategies to satisfy stakeholders ranging from customers to investors. Substantial resources are invested to increase their sustainability engagement to avoid sustainability‐related controversies. However, the degree to which sustainability engagement is effective is an open issue, as the occurrence of sustainability‐related controversies has structural components, which are under the firms' control, but also random components. Using data on firms' sustainability engagement, this paper investigates to what degree firms can actually avoid controversies by engaging in sustainability and to what degree such controversies are caused by factors beyond the firm's control, like random events or the societal environment. Our findings indicate strong sustainability engagement to be a significant factor for avoiding controversies, albeit the magnitude of the effect is very limited. While controversies are not purely random events, they are driven strongly by factors beyond the firm's strategic control, like firm size and country of origin.
Utility of rapid atrial pacing before and after TAVR with balloon‐expandable valve in predicting permanent pacemaker implantation
Authors: Tan Bryan E‐Xin , Hashem Anas , Boppana Leela K. T. , Mohamed Mohamed S. , Abbas Syed Faiz , Faisaluddin Mohammed , Thakkar Samarthkumar , Ahmed Akbar K. , Hall Cameron , Abtahian Farhad , Rao Mohan , Bhatt Deepak L. , Depta Jeremiah P.
Published: September 2023

Background

High‐grade or complete atrioventricular block (AVB) requiring permanent pacemaker (PPM) implantation is a known complication of transcatheter aortic valve replacement (TAVR). Wenckebach AVB induced by rapid atrial pacing (RAP) after TAVR was previously demonstrated in an observational analysis to be an independent predictor for PPM. We sought to investigate the utility of both pre‐ and post‐TAVR RAP in predicting PPM implantation.

Methods

In a single‐center, prospective study, 421 patients underwent TAVR with balloon‐expandable valves (BEV) between April 2020 and August 2021. Intraprocedural RAP was performed in patients without a pre‐existing pacemaker, atrial fibrillation/flutter, or intraprocedural complete AVB to assess for RAP‐induced Wenckebach AVB. The primary outcome was PPM within 30 days after TAVR.

Results

RAP was performed in 253 patients, of whom 91.3% underwent post‐TAVR RAP and 61.2% underwent pre‐TAVR RAP. The overall PPM implantation rate at 30 days was 9.9%. Although there was a numerically higher rate of PPM at 30 days in patients with RAP‐induced Wenckebach AVB, it did not reach statistical significance (13.3% vs. 8.4%, p = 0.23). In a multivariable analysis, RAP‐induced Wenckebach was not an independent predictor for PPM implantation at 30 days after TAVR. PPM rates at 30 days were comparable in patients with or without pre‐TAVR pacing‐induced Wenckebach AVB (11.8% vs. 8.2%, p = 0.51) and post‐TAVR pacing‐induced Wenckebach AVB (10.2% vs. 5.8%, p = 0.25).

Conclusion

In patients who underwent TAVR with BEV, there were no statistically significant differences in PPM implantation rates at 30 days regardless of the presence or absence of RAP‐induced Wenckebach AVB. Due to conflicting results between the present study and the prior observational analysis, future studies with larger sample sizes are warranted to determine the role of RAP during TAVR as a risk‐stratification tool for significant AVB requiring PPM after TAVR.
Preloaded bolted connections with duroplastic gap filling materials
Authors: Makevičius Lukas , Stranghöner Natalie , Korbaj Anas , Werner Philipp , Kunde Carsten , Thelen Sebastian
Published: September 2023

In steel construction, 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. Imperfections due to fabrication and assembly may lead to a gap formation and consequently pose a risk e.g. for the controlled application of the required preload level as well as for the prevention of cavity corrosion. Therefore, the formation of gaps must be kept to a minimum. In cases where packing plates cannot be used, gap filling materials might be an alternative for gap compensation.

MM1018 of Diamant Polymer GmbH represents a two‐component reaction resin system based on epoxy resins. Within the framework of the German (ZIM) cooperation project “Bri‐San‐T ‐ DuroFüllSta”, systematic investigations into the use of MM1018 (liquid and pasty) in preloaded bolted connections were carried out. In addition to the determination of slip factors according to EN 1090 2, Annex G under consideration of various practical boundary conditions such as gap thickness, curing time, temperature and surface condition, also relaxation tests were carried out to determine possible preload losses over the service life of the structure. The presented contribution intends to provide an insight into the main experimental findings for the gap filling material MM1018.
Evaluation of Existing Methods for Predicting Tension Resistance of Gusset Plates with Short Edge Distances
Authors: Shin Yi‐Seop , Kim Hyung‐Joon
Published: September 2023

This study experimentally investigates the tension resistance of gusset plates with different shapes. The yielding and rupture strengths measured from tests were compared with those obtained from existing strength formula suggested by several researchers. The results showed that the existing method overestimated the tension resistance of specimens with short edge distance, which is attributed to the difference in geometries of the target specimens inducing different tensile behavior and stress distribution from gusset plate targeted by existing method. Based on the observations, the influence of the acting moment on the gusset plate should be considered in the prediction of the tension resistance of the gusset plate having a Whitmore section that is restricted to the shape of gusset plate due to short edge distance.
Seismic characterisation of aluminium fusible links in single‐storey steel buildings
Authors: Pasquali Sara , Tondini Nicola , Zanon Gabriele
Published: September 2023

This work is part of the European RFCS “FISHWALL” project entitled “Fire and Seismic performances of hybrid fire walls in case of single‐storey industrial and commercial steel buildings”. The aim of the project is to design a hybrid firewall solution using sandwich panels for single‐storey buildings connected with the unprotected steel structure by means of fusible links, made of aluminium bolts. In this respect, the paper shows the results of preliminary numerical analyses performed on existing case studies of single‐storey steel buildings located in low and moderate seismicity zones and they were used: i) to estimate the seismic forces acting on the fusible links and ii) to subsequently design the specimens to be tested in the laboratory. In this respect, several finite elements models were developed in order to consider the widest range of configurations of the firewall with respect to the direction of the portal frame composing the steel buildings, i.e. firewall parallel and orthogonal to the portal frames. Based on the estimated forces, the design of the six different specimens was performed and it is thoroughly shown in the paper.
Modelling of column base plate connections with plate stiffeners and non‐proportional loading
Authors: Della Corte Gaetano , Cantisani Gaetano
Published: September 2023

Column base plate connections are used widely. Their design is currently codified by Eurocode 3, though with explicit consideration of only base plates without stiffeners and subjected to a proportional loading path. However, both new and existing steel structures might have stiffened base plates. Besides, there might be the need for analyzing the connection response for a non‐proportional loading path (e.g., increasing seismic loads and constant gravity loads). Therefore, the paper provides a contribution into the development of an analytical model for predicting the response of stiffened base plate connections subjected to a non‐proportional loading path. The paper deals with calculation of the connection rotational stiffness and moment resistance. The objective is pursued through finite element modelling and analysis. Then, the application of a proposed analytical model is shown and a comparison with the finite element analysis results is illustrated and discussed.
The Influence of Steel Variability on the Reliability of Welded Beam‐to‐Column Joints
Authors: Skejić Davor , Valčić Anđelo , Žuvelek Vlaho , Čudina Ivan
Published: September 2023

Beam‐to‐column joints have a significant impact on the reliability of load‐bearing steel frame structures. Proper characterisation of the joint behaviour affects the distribution of internal forces and bending moments in frame structural members and affects their reliability level. This article addresses the effect of the variability of steel mechanical properties on the overall behaviour and reliability of welded beam‐to‐column joints. Monte Carlo simulations and parametric numerical analyses were performed to investigate the influence of the variability of mechanical properties on the behaviour (failure modes and resistances) of the joint and to generate data for the reliability analysis. Reliability analyses were performed to calculate partial resistance factors (γM1) for welded steel joints using the procedure given in Annex D of EN 1990. The analyses included the FprEN 1993‐1‐1:2022 and JCSS probabilistic models for mechanical properties of steel and two approaches for determining joint plastic bending resistance. It was concluded that FprEN model gives more favourable values of γM1. It was also found that the approach for determining joint plastic bending resistance can have a large effect on the partial resistance factor γM1 and ultimately on the reliability of the joint.
Innovative One‐way Connections between I‐beams and CHS columns
Authors: Das Rajarshi , Kanyilmaz Alper , Madhouni Mouad , Degee Herve
Published: September 2023

Although stiffeners and gusset plates are often used in conventional I‐beam‐to‐CHS‐column connections for an efficient load transfer, they usually result in high welding quantities. Directly welding the beams to the column exposes the beams to premature flange fractures and the columns to severe local distortions. Both approaches therefore hinder the use of such connections in the industry. However, if designed efficiently, the CHS connections can offer a viable solution with an excellent structural behavior in tension, compression and bending in all directions. In this context, the present contribution proposes two new moment resisting one‐way connection configurations with I‐beams or steel plates passing through the CHS column, developed within the European research project LASTTS, with the aim of simplifying the fabrication process and increasing the structural performance of such joints with an effective reduction of the foretold drawbacks. The “passing‐through” system is developed using a laser cut & weld technology and avoids the localized damages, premature flange failures as well as the excessive usage of stiffening plates required by the conventional CHS connections. These connections are first designed based on a recently developed code‐like procedure and are then assessed through nonlinear finite element models ‐ primarily calibrated on experimental results to validate the modelling assumptions – in order to characterize the influence of the different parameters of the joints.
Geometric tolerances of welded connections with inelastic panel zones
Authors: Wen Ce , Skiadopoulos Andronikos , Lignos Dimitrios G.
Published: September 2023

Prequalified beam‐to‐column connections in steel moment resisting frames usually concentrate inelastic deformations in the steel beam ends. As such, nonlinear geometric instabilities (i.e., local buckling) may occur in these regions at modest lateral drift demands, leading to potentially high residual deformations. Previous research has shown that welded connections featuring inelastic panel zones exhibit a stable hysteretic behaviour. In this case, residual deformations in steel beams are often not visually detectable after inelastic cyclic straining. This paper contrasts the residual deformations of steel beams as part of welded connections with elastic and inelastic panel zones through continuum finite element analyses. The employed finite element model is thoroughly validated with available test data. Besides the actual hysteretic response of the connections, the primary focus of the present work is on a number of geometric tolerance indicators, such as the web concavity, flange out‐of‐square and beam axial shortening. These are strongly correlated to the potential for reuse of structural steel members. The results suggest that connection designs featuring inelastic panel zones delay beam local buckling relative to their strong panel zone counterparts, achieving acceptable residual deformations even at lateral drift demands higher than 4% when considering the geometric tolerances of international standards.
System redundancy of steel I‐girder bridges and proposal of a system factor for load rating
Authors: Okui Yoshiaki , Denda Makoto , Kumaki Kazuki , Sakuma Satoshi
Published: September 2023

3D nonlinear FE analyses of existing plate‐girder bridges were carried out to investigate system redundancy. A comparison of the ultimate live load factors between a whole bridge system (WBS) model and a single girder (SG) model shows that WBS's ultimate live load factor is larger than SG's factor. This difference in the ultimate load factors is interpreted as the system redundancy effect. A system factor to quantify the system redundancy has been proposed based on the nonlinear FE analysis results. The proposed system factor is defined as a factor to convert the ultimate live load factor and rating factor for load rating based on linear analysis into those based on nonlinear analysis. A case study to calculate the system factor for three existing bridges shows dependency of the system factor on the number of girders, composite/non‐composite girders, simple span/continuous span.
Proposal for the suitable choice of material to avoid brittle fracture on Jacket foundations
Authors: Krahl Philipp , Kühn Bertram
Published: September 2023

In the past years offshore wind turbines have been established as a source of renewable energies. Especially installations at greater distances from the shore and thus at increasing sea depths offer great potential. The foundations of these structures are exposed to complex load configurations while simultaneously exhibiting difficult environmental conditions. Although, there are currently no harmonized regulations with regard to the suitable choice of material to avoid brittle fracture for the hollow section joint structure of a Jacket foundation. In accordance with EN 1993‐1‐10 appropriate rules are given in terms of onshore structural engineering. Although, due to the differing conditions, these rules can not be applied to offshore foundations without further modifications. To achieve a suitable application, investigations regarding the material toughness requirements for Jacket foundations of offshore wind turbines were carried out. A parametric study regarding stress concentration was conducted to identify a reference geometry. Afterwards a fracture mechanics approach was applied to define the material toughness requirements. The obtained results served as a basis upon which a proposal to avoid brittle fracture for Jacket foundations was drafted.
Cyclic behavior of single and double‐angle bracing members employed in pipeline‐supporting structures
Authors: Go Hyun , Kim Hyung‐Joon
Published: September 2023

Concentrically braced frames (CBFs) are widely used as the main lateral force‐resisting system in pipeline supporting structures. Their seismic performance mainly depends on the hysteretic response of bracing members. Axial members with single‐ or double‐angle sections have been commonly implemented although there is limited information on their cyclic behavior experimentally verified. This study prepares single‐ and double‐angle brace specimens with various width‐thickness ratios and slenderness ratios, performs cyclic loading tests. and compares their cyclic behavior obtained from the tests and back‐bone curves provided in standard.
Four‐point bending test of composite beam with Concrete‐GFRP cross‐section
Authors: Weissova Michala , Kvocak Vincent , Dubecky Daniel , Vanova Patricia
Published: September 2023

The objective of this study is to explore the application of polymer‐based materials in composite bridges. The paper incorporates both theoretical and practical insights from the field of composite bridges, with a specific focus on shear connectors. The primary aim of this research is to substitute steel with polymer‐based materials in the composite cross‐section. The paper will primarily concentrate on the experimental aspect of the study, employing mechanical analysis through a four‐point bending test. The outcomes of the experiment will encompass the maximum deformation and strength of the composite beam. Such results serve as an impetus for further research and establish the theoretical foundation for designing composite bridges utilizing more environmentally friendly, lightweight, and sustainable materials.
Bulb versus Trough
Authors: Hesselink Bert , Klamer Ernst , Vollema Nynke , Hiddingh Jan , Wijnbeld Bas
Published: September 2023

With the increasing traffic intensity and traffic loads, it can be questioned whether the application of orthotropic steel decks with troughs as longitudinal stiffeners is still the best solution. Possibly, the use of bulb profiles as longitudinal stiffeners could offer a better solution. Bulb profiles were commonly used till the late sixties but are no longer applied due to high manufacturing costs. However, new welding techniques have become available nowadays, which could possibly eliminate this disadvantage. In this study, a comparison is made between an orthotropic deck with troughs and with bulb profiles. For both deck types, an optimized design is made with respect to fatigue, after which both designs are compared with respect to weight, costs, production, maintenance, and inspection. Surprising outcome is that the bulb deck can be more favorable on certain aspects compared to the more recent trough deck.
3D‐printing with steel on thin sheets for application in free form façade construction: welding process development and material properties
Authors: Grebner Philipp , Lange Jörg
Published: September 2023

Wire and Arc Additive Manufacturing (WAAM) became a significant research field in structural engineering over the past years. It offers the opportunity to apply material fast and precisely, following the load path, inducing effective material consumption. Considering free‐formed sheet‐metal façades, to date large thicknesses are necessary to maintain the final shape and load‐bearing capacity that however causes high material consumption and costs during the construction processes. Hence, WAAM could be an opportunity to reduce the amount of mild steel used for free‐form façades. As part of a research project at TU Darmstadt, 1 mm thick free‐form sheet‐metal façades elements have been manufactured using WAAM. Due to precisely welded lattice structures, placed on the backside of the metal sheet, the reinforcement will be ensured. Wide studies on welding parameters focused on a stable process without damaging the later frontside of the façade panel and on process optimization. In addition, material properties of the welding material have been determined to check its usability in façade construction.
Gerda Taro Bridge ‐ a semi integral composite bridge
Authors: Boeters Ton , Cornelissen Lieuwe , Hesselink Bert
Published: September 2023

For the area developments on IJburg in Amsterdam, there was a need to connect the various islands with the mainland. The connection between the ‘Centrumeiland’ and the ‘Strandeiland’ is the Gerda Taro Bridge; with ‘Bridge 2125’ as project name. The Gerda Taro Bridge is part of the bridge family ‘Buitenwater’. The bridge is suitable for all types of road traffic and has a total length of approximately 115m.

Royal HaskoningDHV did the complete engineering of the road bridge for both the tender phase and all design phases up to and including implementation in collaboration with contractor Ballast Nedam.

The Gerda Taro Bridge consists of a steel‐concrete supporting structure. Both the main girders and cross girders consist of welded I‐sections. The concrete deck is connected by means of studs, ensuring composite action between the steel and the concrete. The deck structure is supported by spatially oriented steel hollow sections on five intermediate supports.
Influence of Imperfections in the Design of Crane Runway I‐Beams
Authors: Kováč Michal , Ároch Rudolf
Published: September 2023

Crane runway beams are generally loaded by vertical and horizontal forces as well as not‐negligible torsional actions. Horizontal and torsional deformations originate already from the 1st order analysis. The effects of imperfections of crane runway beams could, at least partially, be simulated by these deformations. While for the purely vertically loaded beams it is necessary to consider the horizontal bow imperfection, for the generally loaded beams with horizontal forces as well, the influence of horizontal bow imperfection may not be as important, due to the occurrence of horizontal deflection from primary actions. Eurocode EN 1993‐6 allows to consider either eccentricities of vertical forces or introduction of horizontal bow imperfections in the design of crane runway beams. In this article, using a self‐developed FEM‐program, the effect of horizontal bow imperfection for the generally loaded crane runway beams is investigated. The two options of EN 1993‐6 are compared in the FEM analyses with the simplified design methods like the Annex A method of the same standard and the Naumes method.
Measurement and statistical analysis of deviations in the cross‐sectional geometry of hot‐rolled I‐sections
Authors: Steinmetz Robin , Taras Andreas
Published: September 2023

In the second generation of EN 1993‐1‐1, the variation in geometric and mechanical properties of European steel products are now statistically described in a dedicated “Annex E”. The partial safety factors γM for the resistance functions (design equations for strength) were calibrated based on these assumptions. However, while most past research has focused strongly on the mechanical properties and thus the corresponding scatter quantities are well known, there are still a few open aspects regarding the cross‐sectional dimensions. Due to this background and as an independent confirmation of the EN‐values with most recent data, in the present study a detailed measurement campaign on hot‐rolled I‐sections was carried out directly at depots of steel merchants in Switzerland. A total of 561 cross‐sections were measured and analysed. The results helped corroborate the characterisation in Annex E.
Influence of Temperature on the Behavior of Sandwich Panels
Authors: Steineck Sonja , Lange Jörg
Published: September 2023

Sandwich panels in the construction industry are used as roof and facade elements and usually consist of two thin face layers of steel and a thicker core of polyurethane (PU) or mineral wool in between. The PU core material is constantly being further developed. In addition to improvements in the physical properties, this further development also leads to changes in the mechanical properties. As a result, the design rules that were established for older foam systems must be reviewed at regular intervals. There is a great need for research into the temperature‐dependent behavior of the foam system. As these elements are used as roof and facade elements, they are directly exposed to climatic conditions. High temperatures are generated on the cover sheets due to solar radiation. The PU rigid foam changes its mechanical properties in this temperature range. Tests on small parts and components show a change in the stiffnesses and strengths, as well as the load‐bearing behavior under elevated temperature. Consideration of the temperature in the design is therefore of great importance. In view of the continuous further development of the foam system, statements regarding the core material from older research must be reconsidered.
Stress increases in crane runway girders due to rail joints
Authors: Kettler Markus , Unterweger Harald
Published: September 2023

Vertically acting wheel loads from overhead bridge cranes and potential additional horizontal crane loads induce two types of stresses in crane runway girders: i) global stresses due to bi‐axial bending and torsion and ii) local stresses which mainly affect the girder's web. The latter typically represent one of the most decisive criteria for the fatigue design check of welded girders and are the focus of this paper. Crane rails with foot flange are typically connected to the top flange with rail clips. These clips maintain the position of the rail in vertical and horizontal transverse direction, but they generally allow for longitudinal movement of the rail. Rails with foot flange are used with and without elastomeric bearing pads between the rail and the top flange of the girder. The local stresses in the webs of crane runway girders are strongly affected by discontinuities of the crane rails. Such discontinuities can originate from unplanned rail cracks as well as planned rail expansion joints. The current mechanical models for concentric as well as eccentric wheel loading in relevant design standards assume continuous crane rails. However, rail joints are expected to significantly increase the local stresses in the region beneath rail joints. The present paper focuses on the impact of rail joints on the local stresses in crane runway girders. The research activities comprise experimental tests as well as finite element calculations. The aim of the investigations is to develop a better understanding of the mechanical behaviour in order to avoid future fatigue damage due to an unexpected increase of local stresses at a rail joint.