bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation of a novel inorganic cubic perovskite Ca3PI3 with unique strain‐driven optical, electronic, and mechanical properties
Authors: Rahman Md. Ferdous , Islam Md. Al Ijajul , Islam Md. Rasidul , Ali Md. Hasan , Barman Pobitra , Rahman Md. Azizur , Harun‐Or‐Rashid Md. , Hasan Mehedi , Hossain M. Khalid 
Published: September 2023

AbstractThe remarkable structural, optical, and electronic characteristics of inorganic perovskite materials have generated significant enthusiasm within the field of solar technology. The material Ca3PI3 belongs to the same category as inorganic metal halide perovskites. This research utilized the first‐principles density functional theory (FP‐DFT) to examine how the optical and electronic characteristics of Ca3PI3 are impacted by strain. To accurately determine the band arrangement, we incorporated the relativistic spin‐orbit coupling (SOC) effect into our calculations. The planar Ca3PI3 molecule has a direct bandgap of 1.582 eV (PBE) at its Г(gamma)‐point, but while the relativistic SOC effect is included, the bandgap decreases to 1.329 eV. Under compressive strain, the bandgap of all structures decreases, whereas under tensile strain, it increases. The optical characteristics of Ca3PI3, including the dielectric function, absorption coefficient, and electron loss function, indicate its strong absorption capabilities in the visible range, driven by its band properties. Besides, the photon energy spectrum displays a red‐shift (blue‐shift) in the absorption coefficient and dielectric function with increasing amounts of compressive (tensile) strain. Therefore, the study of the strain‐induced optical and electronic characteristics of Ca3PI3 bears valuable implications for its potential use in the design of solar cells and optoelectronic devices.
Robocasting of ordered mesoporous silica‐based monoliths: Rheological, textural, and mechanical characterization
Authors: Dal Molin Emiliano S. , Henning Laura M. , Müller Julian T. , Smales Glen J. , Pauw Brian R. , Bekheet Maged F. , Gurlo Aleksander , Simon Ulla 
Published: September 2023

AbstractHierarchically porous, high‐surface‐area silica materials are excellent candidates for multiple applications like catalysis and environmental remediation. Shaping these materials with additive manufacturing (AM) techniques, like robocasting, could enable their use with the benefit of on‐demand, customized shaping and maximizing performance. Herein, ordered mesoporous silica COK‐12 slurries were robocasted into monoliths, containing different ratios of uncalcined COK‐12 and sodium bentonite (0–25 wt.%). The rheology of the mixed slurries is characterized by lower flow indexes (0.69 vs. 0.32) and higher yield stresses (96 vs. 259 Pa) compared to pure COK‐12 ones. Monoliths were printed in woodpile structures and calcined at 600°C. Micro‐CT measurements showed a linear shrinkage of 25% after calcination. Mechanical characterization showed increased uniaxial strength (0.20 ± 0.07 to 1.0 ± 0.3 MPa) with increasing binder/solids ratio from 13 to 25%. The amorphous, mesoporous structure of COK‐12 was retained. The structures exhibited open porosities of 52 ± 4% and showed higher specific mesopore volumes, and increased average mesopore size (6 vs. 8 nm) compared to COK‐12. Small‐angle x‐ray scattering analysis revealed an increased lattice parameter (10.3 vs. 11.0 nm) and reduced wall thickness (3.1 nm vs. 4.1 nm) of the COK‐12 in the monoliths. These properties indicate suitability for their application as porous supports and adsorbents.
Incorporating uncertainty in stress‐strain data acquisition: extended model‐free data‐driven identification
Authors: Zschocke Selina , Graf Wolfgang , Kaliske Michael 
Published: September 2023

AbstractBased on the increasing ability to collect and store large amounts of data and information, data‐driven methods have recently gained importance in the context of computational mechanics. Compared to the traditional approach of defining a suitable constitutive model and fit the parameters to experimental data, these methods aim to capture complex material behavior without the assumption of a certain material formulation. Distinguished are model‐based data‐driven methods, leading to an approximation of the constitutive material description for example, by neural networks, and model‐free data‐driven methods. The approach of data‐driven computational mechanics (DDCM), introduced by Kirchdoerfer and Ortiz (2016), enables to circumvent any material modeling step by directly incorporating material data into the structural analysis. A basic prerequisite for both types of data‐driven methods is a large amount of data representing the material behavior, in solid mechanics consisting of stresses and strains. Obtaining these databases numerically by multiscale approaches is computationally expensive and requires the definition of lower scale models. In case of an experimental characterization, constitutive descriptions are generally required to compute the stress states corresponding to displacement fields, for example, identified by full‐field measurement techniques, such as digital image correlation (DIC). The method of data‐driven identification (DDI), introduced in Leygue et al. (2018) based on the principles of DDCM, enables the determination of detailed information about the constitutive behavior based on displacement fields and applied boundary conditions without a specific material model. Stresses corresponding to given strains are identified by iteratively clustering and enforcing equilibrium. The algorithm has shown to be applicable to synthetic as well as real data taking linear and non‐linear material behavior into account. Generalized polymorphic uncertainty models, resulting as a combination of aleatoric and epistemic uncertainty models, are utilized to take variability, imprecision, inaccuracy and incompleteness of data into account. The consideration of uncertain material properties by data‐driven simulation approaches leads to the requirement of data sets representing uncertain material behavior. In this contribution, different sources of uncertainty occurring within DDI of stress‐strain relations are addressed and an efficient method for the identification of data sets representing uncertain material behavior based on the concept of DDI is proposed. In order to demonstrate the developed methods, numerical examples are carried out.
Catalog of Dynamical System Models with Semantic Metadata
Authors: Fiedler Julius , Knoll Carsten 
Published: September 2023

AbstractThis contribution presents the concept and implementation of a catalog (i.e., a structured collection) of dynamical system models, relevant to control theory. The key features of the catalog are: (a) a combination of human‐readable model documentation with executable code; (b) semantic metadata for each model plus a web platform to provide SPARQL search interface; and (c) model data and supporting software based on open source repositories and open for extension and improvement.
Convex reconstruction of moving particles with inexact motion model
Authors: Hahn Bernadette , Wirth Benedikt 
Published: September 2023

AbstractWe propose a novel convex optimization problem for the reconstruction of temporally moving nonnegative point sources or particles. As in previously developed approaches from the literature, we base our reconstruction on a linear motion model in which particles move at constant d‐dimensional velocity. However, in contrast to existing approaches we allow a deviation from the exact linear motion, thereby accounting for the modelling error inherent in that motion model. The deviation is measured with the help of Wasserstein distances and is constrained not to exceed a freely selectable bound which represents the model inexactness. We show well‐posedness and first numerical results for the model.
Modeling the material behavior of heterogeneous materials considering a two‐scale FE–FFT‐based simulation framework
Authors: Schmidt Annika , Gierden Christian , Waimann Johanna , Reese Stefanie 
Published: September 2023

AbstractIn various engineering applications, components subjected to high mechanical or multi‐physical loads such as thermal, thermo‐mechanical, or electro‐thermal loads are predominantly made of metals or composites. These materials are characterized by polycrystalline or multi‐phase microstructures which determine the overall material response. However, since the microscopic material behavior is directly related to the distribution, size, and morphology of the individual grains or phase constituents, precise predictions of the macroscopic material response require simulations of the microstructural behavior. Hence, this work considers a two‐scale finite element (FE) and fast Fourier transform (FFT)‐based simulation framework, which is an efficient alternative to the classical method for the simulation of periodic unit cells. Assuming scale separation, the macroscopic and microscopic boundary value problems are first solved individually and subsequently linked by performing a scale transition in terms of averaging the macroscopic quantities over the corresponding local fields. While the macroscopic solution is computed by means of the finite element method, the microscopic boundary value problem, which is embedded as a periodic unit cell in each macroscopic integration point, is solved using an FFT‐based simulation method. In general, these microscopic simulations allow to model grain‐scale phenomena such as martensitic phase transformation or plastic deformation caused by dislocation glide which can be observed in polycrystalline materials. In this work, we present a two‐scale FE–FFT‐based model to capture the martensitic phase transformations in shape memory alloys. In order to demonstrate the applicability of the model, a numerical example is given.
Coupled clustering strategies for hierarchical matrix preconditioners in saddle point problems
Authors: Grams Jonas , Le Borne Sabine 
Published: September 2023

AbstractFluid flow problems can be modeled by the Navier–Stokes or, after linearization, by the Oseen equations. Their discretization results in discrete saddle point problems. These systems of equations are typically very large and need to be solved iteratively. Standard (block‐) preconditioning techniques for saddle point problems rely on an approximation of the Schur complement. Such an approximation can be obtained by a hierarchical (‐) matrix LU‐decomposition, which first approximates the Schur complement explicitly. The computational complexity of this computation depends, among other things, on the hierarchical block structure of the involved matrices. However, widely used techniques do not consider the connection between the discretization grids for the velocity field and the pressure, respectively. Here, we present a hierarchical block structure for the finite element discretization of the gradient operator that is improved by considering the connection between the two involved grids. Numerical results imply that the improved block structure allows for a faster computation of the Schur complement, which is the bottleneck for the set‐up of the ‐matrix LU‐decomposition.
Adaptive MOR techniques for non‐linear FE simulations of unit cells
Authors: Özmen Yasemin , Niekamp Rainer , Nigro Paulo S. B. , Schröder Jörg 
Published: September 2023

AbstractThis work shows an adaptive Model Order Reduction (MOR) scheme for the computation of unit cells with non‐linear material behavior. A reduction of dimensionality and computational cost is achieved by projecting the high‐fidelity system of equations (SOE) from the full vector space to a lower dimensional subspace. An adaptive algorithm updates the projection operator, which is initially gained from a Proper Orthogonal Decomposition (POD), to ensure convergence and optimal size control of the reduced problem. Numerical examples show a comparison between the discretization of full displacements and fluctuations of a hexagonal unit cell, which show the independence of the MOR basis from the macroscopic displacements.
Numerical implementation of tension–compression asymmetry in a gradient‐extended two‐surface damage–plasticity model
Authors: Zhang Jian , Brepols Tim , Reese Stefanie 
Published: September 2023

AbstractBased on the spectral decomposition of the strain tensor, the tension‐compression asymmetry (TCA) in a gradient‐extended two‐surface damage‐plasticity model is considered in this study. More specifically, the gradient extension is applied in the current model as a suitable damage regularization technique to prevent pathological mesh dependence issues. Furthermore, plasticity and damage are treated as distinct but strongly coupled dissipative mechanisms by using two different types of damage and yield criteria as well as the related loading/unloading conditions, respectively. Finally, a specific material parameter is adopted to control the degree of TCA which results in a unique damage evolution in compression.
A variational approach for temporal multiscale problems and its application to adaptivity and optimization
Authors: Dominguez Dayron , Lautsch Leopold , Richter Thomas 
Published: September 2023

AbstractWe discuss a computational multiscale method for the efficient simulation and optimization of differential equations with multiple scales in time. The approach is based on isolating the influences of the fast scale by a local periodic‐in‐time assumption that allows for time‐stepping of the averaged slow scale with very large step sizes. For this approach we develop a variational formulation that gives easy access to the methodology of goal‐oriented error estimation and adaptivity as well as gradient based optimization.
Transient response of pavement structures under moving wheel loads using the ALE methodology
Authors: Anantheswar Atul , Wollny Ines , Kaliske Michael 
Published: September 2023

AbstractThe dynamic response of long structures (e.g., pavements) subjected to moving loads is generally difficult to simulate using conventional methods like the finite element method in the Lagrangian setting. This is because the entire length of the structure in the path of the moving load would need to be discretized, and in turn would require large meshes. Additionally, if improvement in quality of results through the use of finer mesh sizes is sought, the entire region of the mesh in the load path would require refinement. As a direct result, long simulation run‐times can be expected when using conventional methods. To overcome these drawbacks, and improve the efficiency of the finite element simulations, the Arbitrary Lagrangian Eulerian (ALE) approach can be used to simulate pavement structures, provided longitudinal homogeneity is assumed. This contribution uses an extension of the quasi‐static ALE framework to the transient domain, enabling the study of the dynamic response of pavement structures subjected to moving loads. In this work, some case studies are considered to highlight the capabilities of this dynamic ALE framework.
Investigation on the short‐term outcome and prognostic impact of predisposition, and precipitants in inpatients with chronic liver disease from Chinese AcuTe on CHronic LIver FailurE (CATCH‐LIFE) cohorts
Authors: Zhang Yan , Tan Wenting , Wang Xiaobo , Zheng Xin , Huang Yan , Li Beiling , Meng Zhongji , Gao Yanhang , Qian Zhiping , Liu Feng , Lu Xiaobo , Shang Jia , Zheng Yubao , Zhang Weituo , Yin Shan , Gu Wenyi , Wang Tongyu , Wei Jianyi , Shen Zixuan , Deng Guohong , Zhou Yi , Hou Yixin , Zhang Qun , Xiong Shue , Liu Jing , Long Liyuan , Chen Ruochan , Chen Jinjun , Jiang Xiuhua , Luo Sen , Chen Yuanyuan , Jiang Chang , Zhao Jinming , Ji Liujuan , Mei Xue , Li Jing , Li Tao , Zheng Rongjiong , Zhou Xinyi , Ren Haotang , Shi Yu , Li Hai ,   for the CATCH‐LIFE Study Investigators of Chinese (Acute‐on) Chronic Liver Failure (CLIF) Consortium (Ch‐CLIF.C)
Published: September 2023

AbstractAimThe study aimed to investigate the short‐term outcomes of hospitalized patients with chronic liver disease (CLDs) and assess the prognostic impact of predisposition and precipitants, which currently remains unclear.MethodsThe study included 3970 hospitalized patients with CLDs from two prospective longitudinal multicenter studies (NCT02457637 and NCT03641872) conducted in highly endemic hepatitis B virus (HBV) areas. Competing risk analysis was used to evaluate the effect of predispositions, including the etiology and severity of CLDs and precipitants; on sequential 28, 90, and 365‐day liver transplantation (LT)‐free mortality.ResultsAmong all enrolled patients, 76.8% of adverse outcomes (including death and LT) within one year occurred within 90 days. Compared with alcoholic etiology, the association of HBV etiology with poorer outcomes was remarkably on the 28th day (hazard ratio [HR], 1.81; 95% confidence interval [CI], 1.07–3.06; p = 0.026); however, and diminished or became insignificant at 90 days and 365 days. Cirrhosis increased the adjusted risk for 365‐day (HR, 1.50; CI, 1.13–1.99; p = 0.004) LT‐free mortality when compared with noncirrhosis. In patients with cirrhosis, prior decompensation (PD) independently increased the adjusted risk of 365‐day LT‐free mortality by 1.25‐fold (p = 0.021); however, it did not increase the risk for 90‐day mortality. Neither the category nor the number of precipitants influenced the adjusted risk of 28 or 90‐day LT‐free mortality.ConclusionsThe 90‐day outcome should be considered a significant endpoint for evaluating the short‐term prognosis of hospitalized patients with CLD. Predisposing factors, other than etiology, mainly affected the delayed (365‐day) outcome. Timely effective therapy for CLD etiology, especially antiviral treatments for HBV, and post‐discharge long‐term surveillance monitoring in cirrhotic patients undergoing PD are suggested to enhance disease management and reduce mortality.
Impact of the COVID‐19 pandemic on care disruptions, outcomes, and costs in patients receiving pulmonary arterial hypertension‐specific therapy in the United States of America: An observational study
Authors: George Marjorie Patricia , Germack Hayley D. , Goyal Amit , Ward Charlotte , Studer Sean , Panjabi Sumeet 
Published: September 2023

AbstractRegular expert follow‐up, risk assessment, and early therapeutic intervention minimize worsening of pulmonary arterial hypertension (PAH). COVID‐19 lockdown measures were challenging for chronic disease management. This retrospective, longitudinal analysis used US claims data (January 12, 2016 to September 11, 2021) for patients treated with PAH‐specific medication to compare in‐person outpatient and specialist visits, telemedicine visits, and PAH‐related tests during 6‐month assessment periods pre‐ and immediately post‐COVID‐19. Hospitalizations, costs, and outcomes were compared in patients with and without care disruptions (no in‐person or telemedicine outpatient visits in immediate post‐COVID‐19 period). Patients in the immediate post‐COVID‐19 (N = 599) versus the pre‐COVID‐19 period (N = 598) had fewer in‐person outpatient visits (mean 1.27 vs. 2.12) and in‐person specialist visits (pulmonologist, 22.9% vs. 37.0% of patients; cardiologist, 27.5% vs. 33.8%); and more telemedicine visits (mean 0.45 vs. 0.02). In the immediate post‐COVID‐19 period, patients were less likely to have a PAH‐related test versus the pre‐COVID‐19 period (incidence rate ratio: 0.700; 95% confidence interval: 0.615−0.797), including electrocardiograms (41.7% vs. 54.2%) and 6‐minute walk distance tests (16.2% vs. 24.9%). In the immediate post‐COVID‐19 period, 48 patients had care disruptions and, in the following year, required more hospital days than those without care disruptions (N = 240) (median 10 vs. 5 days in total) and had higher overall hospitalization costs (median US$34,755 vs. US$20,090). Our findings support the need for minimizing care disruptions to potentially avoid incremental post‐disruption healthcare utilization and costs among patients with serious chronic diseases such as PAH.
Peak steps: Capacity for activity improves after adding approved therapy in pulmonary arterial hypertension
Authors: Lachant Daniel , Light Allison , Lachant Michael , Annis Jeffrey , Hemnes Anna , Brittain Evan , White R. James 
Published: September 2023

AbstractPulmonary arterial hypertension (PAH) patients have low activity. Activity intensity or duration could be a measure of clinical status or improvement. We aimed to determine whether standard or novel actigraphy measures could detect increases in activity after adding therapy. This was a prospective, single‐center observational study evaluating activity after adding therapy in Group 1 PAH; we also report a validation cohort. For our study, two different accelerometers were used, a wrist (ActiGraph) and chest (MC10) device. Patients were analyzed in two groups, Treatment Intensification (TI, adding therapy) or Stable. Both groups had baseline monitoring periods of 7 days; the TI group had follow‐up at 3 months, while Stables had follow‐up within 4 weeks to assess stability. Activity time and steps were reported from both devices' proprietary algorithms. In ActiGraph only, steps in 1‐min intervals throughout the day were ranked (not necessarily contiguous). Average values for each week were calculated and compared using nonparametric testing. Thirty patients had paired data (11 Stable and 19 TI). There was no between‐group difference at baseline; we did not observe therapy‐associated changes on average daily steps or activity time/intensity. The top 5 min of steps (capacity) increased after adding therapy; there was no difference in the stable group. This key finding was validated in a previously reported randomized trial studying a behavioral intervention to increase exercise. Total daily activity metrics are influenced by both disease and non‐disease factors, making therapy‐associated change difficult to detect. Peak minute steps were a treatment‐responsive marker in both a pharmacologic and training intervention.
Man versus machine: Automatic pedicle screw planning using registration‐based techniques compared with manual screw planning for thoracolumbar fusion surgeries
Authors: Bertram Ulf , Köveshazi Istvan , Michaelis Monika , Weidert Simon , Schmidt Tobias Philip , Blume Christian , Zastrow Felix Swamy v. , Müller Christian‐Andreas , Szabo Szilard 
Published: September 2023

AbstractObjectiveThis study evaluates the precision of a commercially available spine planning software in automatic spine labelling and screw‐trajectory proposal.MethodsThe software uses automatic segmentation and registration of the vertebra to generate screw proposals. 877 trajectories were compared. Four neurosurgeons assessed suggested trajectories, performed corrections, and manually planned pedicle screws. Additionally, automatic identification/labelling was evaluated.ResultsAutomatic labelling was correct in 89% of the cases. 92.9% of automatically planned trajectories were in accordance with G&R grade A + B. Automatic mode reduced the time spent planning screw trajectories by 7 s per screw to 20 s per vertebra. Manual mode yielded differences in screw‐length between surgeons (largest distribution peak: 5 mm), automatic in contrast at 0 mm. The size of suggested pedicle screws was significantly smaller (largest peaks in difference between 0.5 and 3 mm) than the surgeon's choice.ConclusionAutomatic identification of vertebrae works in most cases and suggested pedicle screw trajectories are acceptable. So far, it does not substitute for an experienced surgeon's assessment.