bluuebunny/crossref_metadata_2025_split huggingface dataset:
Alternative analytic and matching approaches for the prevalent new‐user design: A simulation study
Authors: Webster‐Clark Michael , Mavros Panagiotis , Garry Elizabeth M. , Stürmer Til , Shmuel Shahar , Young Jessica , Girman Cynthia 
Published: May 2022

AbstractPurposeTo describe the creation of prevalent new user (PNU) cohorts and compare the relative bias and computational efficiency of several alternative analytic and matching approaches in PNU studies.MethodsIn a simulated cohort, we estimated the effect of a treatment of interest vs a comparator among those who switched to the treatment of interest using the originally proposed time‐conditional propensity score (TCPS) matching, standardized morbidity ratio weighting (SMRW), disease risk scores (DRS), and several alternative propensity score matching approaches. For each analytic method, we compared the average RR (across 2000 replicates) to the known risk ratio (RR) of 1.00.ResultsSMRW and DRS yielded unbiased results (RR = 0.998 and 0.997, respectively). TCPS matching with replacement was also unbiased (RR = 0.999). TCPS matching without replacement was unbiased when matches were identified starting with patients with the shortest treatment history as initially proposed (RR = 0.999), but it resulted in very slight bias (RR = 0.983) when starting with patients with the longest treatment history. Similarly, creating a match pool without replacement starting with patients with the shortest treatment history yielded an unbiased estimate (RR = 0.997), but matching with the longest treatment history first resulted in substantial bias (RR = 0.903). The most biased strategy was matching after selecting one random comparator observation per individual that continued on the comparator (RR = 0.802).ConclusionsMultiple analytic methods can estimate treatment effects without bias in a PNU cohort. Still, researchers should be wary of introducing bias when selecting controls for complex matching strategies beyond the initially proposed TCPS.
“Particle‐on‐plane” hybrid of ZnO‐reduced graphene oxide: Roles on mechanical and tribological performances of thermosetting polyimide
Authors: Luo Rong , He Yan , Liu Hong , Wang Jinqing , Yang Shengrong 
Published: May 2022

AbstractIn this article, a hybrid of reduced graphene oxide (rGO) sheets decorated by zinc oxide (ZnO) particles was synthesized by a simple hydrothermal method, and its thermosetting polyimide (TPI) composites were prepared by an in situ polymerization method. The mechanical and tribological properties of the ZnO–rGO/TPI composite under dry sliding conditions were studied. The compression strength and modulus of 0.8 wt% ZnO–rGO/TPI composite reached 120.67 ± 2 MPa and 1.77 ± 0.06 GPa, which were 28.1% and 51.3% higher than those of TPI, respectively. The wear rate of 0.8 wt% ZnO–rGO/TPI was also reduced to 1.54 × 10−8 mm3 N−1 m−1 at 100 N load, which is about two order of magnitude lower than that of TPI. Compared with the addition of GO alone, the results also demonstrate more significant enhancements in mechanical and tribological properties of TPI by ZnO–rGO hybrid. Furthermore, the tribological mechanism exploration indicates that the “particle‐on‐plane” structure and chemical bonding between ZnO and rGO lead to the crack suppression and strength increment, contributing to the extraordinary improvement of mechanical and tribological properties. Thus, this ZnO–rGO/TPI composite presents promising potential as high‐performance tribological materials under dry‐sliding conditions in industrial applications.
Processability and physico‐mechanical properties of ultrahigh‐molecular‐weight polyethylene using low‐molecular‐weight olefin wax
Authors: Bakshi Ashok Kumar , Ghosh Anup K. 
Published: May 2022

AbstractThe influence of molecular weight of olefin wax as a plasticizer on the processability and properties of ultrahigh‐molecular‐weight polyethylene (UHMWPE) was thoroughly investigated in this study. Two different grades of olefin wax (H5 and 210P) were used separately to plasticize UHMWPE. Comparative results were analyzed based on mixing torque, mechanical, thermal, thermo‐mechanical, and morphological aspects. The Gaussian mathematical model was applied to the internal thermo‐shear batch mixing torque data to predict processability and plasticization of the resulting compounds. A decrease in the peak torque value with increase in wax content revealed the plasticization effect. Across both types of wax (H5 and 210P) at 4, 8, and 10 phr content, the 10 phr H5 wax plasticized UHMWPE batch showed a minimum peak torque of 4.5 Nm with a broad mixing temperature window (∆T) of 32.4°C. The relatively low‐molecular‐weight wax (H5) seemed to be more efficient at uncoiling the entanglements among the amorphous phase of UHMWPE, perhaps because of its smooth interpenetration between ties. The lowest degree of crystallinity range (34%–40%) and the highest nucleation rate (0.9 min−1) were found with 10 phr H5 wax plasticized UHMWPE. The tensile strength of 30.5 MPa and elastic modulus of 127 MPa, achieved by the addition of H5 wax at 10 phr loading, confirmed the optimum effect of plasticization. The plasticization effect was also established from the loss moduli and Cole–Cole plots (log loss modulus vs. log storage modulus). A smaller number of multiple stress‐induced overshoots and the inclining approach toward the viscous dominant regime with temperature sweep were observed in the case of 10 phr H5 wax composition. Scanning electron microscopy (SEM) analysis revealed disappearance of interfacial crazing and interparticle boundaries progressively with the increase in H5 wax content. Overall, plasticized UHMWPE with 10 phr content of H5 wax showed the optimum processability and properties.
Silicon solar cells with passivating contacts: Classification and performance
Authors: Yan Di , Cuevas Andres , Stuckelberger Josua , Wang Er‐Chien , Phang Sieu Pheng , Kho Teng Choon , Michel Jesús Ibarra , Macdonald Daniel , Bullock James 
Published: May 2022

AbstractThe year 2014 marks the point when silicon solar cells surpassed the 25% efficiency mark. Since then, all devices exceeding this mark, both small and large area, with contacts on both sides of the silicon wafer or just at the back, have utilized at least one passivating contact. Here, a passivating contact is defined as a group of layers that simultaneously provide selective conduction of charge carriers and effective passivation of the silicon surface. The widespread success of passivating contacts has prompted increased research into ways in which carrier‐selective junctions can be formed, yielding a diverse range of approaches. This paper seeks to classify passivating contact solar cells into three families, according to the material used for charge‐carrier selection: doped amorphous silicon, doped polycrystalline silicon, and metal compounds/organic materials. The paper tabulates their current efficiency values, discusses distinctive features, advantages, and limitations, and highlights promising opportunities going forth towards even higher conversion efficiencies.
A theory of finite tensile deformation of double‐network hydrogels
Authors: Shams Es‐haghi Siamak , Weiss Robert A. 
Published: May 2022

AbstractA continuum damage model was developed to describe the finite tensile deformation of tough double‐network (DN) hydrogels synthesized by polymerization of a water‐soluble monomer inside a highly crosslinked rigid polyelectrolyte network. Damage evolution in DN hydrogels was characterized by performing loading‐unloading tensile tests and oscillatory shear rheometry on DN hydrogels synthesized from 3‐sulfopropyl acrylate potassium salt (SAPS) and acrylamide (AAm). The model can explain all the mechanical features of finite tensile deformation of DN hydrogels, including idealized Mullins effect and permanent set observed after unloading, qualitatively and quantitatively. The constitutive equation can describe the finite elasto‐plastic tensile behavior of DN hydrogels without resorting to a yield function. It was showed that tensile mechanics of DN hydrogels in the model is controlled by two material parameters which are related to the elastic moduli of first and second networks. In effect, the ratio of these two parameters is a dimensionless number that controls the behavior of material. The model can capture the stable branch of material response during neck propagation where engineering stress becomes constant. Consistent with experimental data, by increasing the elastic modulus of the second network the finite tensile behavior of the DN hydrogel changes from necking to strain hardening.
Development of an analysis and testing concept for the evaluation of impact targets in the mechanical safety testing of dangerous goods packagings
Authors: Lengas Nikolaos , Müller Karsten , Schlick‐Hasper Eva , Neitsch Marcel , Johann Sergej , Zehn Manfred 
Published: May 2022

AbstractThe mechanical and geometrical properties of impact targets greatly influence the outcome of a drop test. The International Agreement concerning the International Carriage of Dangerous Goods by Road (ADR) as well as ISO 2248 describe the characteristics of impact targets for drop tests of dangerous goods packagings. According to these regulations, the impact target's surface needs to be unyielding, under testing conditions non‐deformable, flat and integral with a mass at least 50 times that of the heaviest packaging to be tested. The problem is that many production facilities, especially manufacturers of corrugated fibreboard boxes, do not have their own testing device with the required 50 times mass ratio of the impact target for a regulation compliant drop test during series production. Furthermore, at UN level, it is considered necessary to revise these requirements. In the present paper, the impact target requirements are examined in detail and compared with those in other technical areas (e.g., impact target for container for the transport of radioactive materials). A research method is being developed to investigate the dependency between the mass ratio of the packaging and the target as well as the damage resistance of a drop tested package in relation to specific design characteristics. The results are of high relevance for industry purposes and intended to ensure a uniform level of safety assessment for the mechanical testing of dangerous goods packagings.
Effective buoyancy and CAPE: Some implications for tropical cyclones
Authors: Smith R. K. , Montgomery M. T. 
Published: May 2022

AbstractWe review the widely used concepts of “buoyancy” and “convective available potential energy” (CAPE) in relation to deep convection in tropical cyclones and discuss their limitations. A fact easily forgotten in applying these concepts is that the buoyancy force of an air parcel, as often defined, is non‐unique because it depends on the arbitrary definition of a reference density field. However, when calculating CAPE, the buoyancy of a lifted air parcel is related to the specific reference density field along a vertical column passing through that parcel. Both concepts can be generalized for a vortical flow and to slantwise ascent of a lifted air parcel in such a flow. In all cases, the air parcel is assumed to have infinitely small dimensions. In this article, we explore the consequences of generalizing buoyancy and CAPE for buoyant regions of finite size that perturb the pressure field in their immediate environment. Quantitative calculations of effective buoyancy, defined as the sum of the conventional buoyancy and the static vertical perturbation pressure gradient force induced by it, are shown for buoyant regions of finite width. For a judicious choice of reference density, the effective buoyancy per unit mass is essentially a unique force, independent of the reference density, but its distribution depends on the horizontal scale of the buoyant region. A corresponding concept of “effective CAPE” is introduced and its relevance to deep convection in tropical cyclones is discussed. The study is conceived as a first step to understanding the decreasing ability of inner‐core deep convection in tropical cyclones to ventilate the mass of air converging in the frictional boundary layer as the vortex matures and decays.
Varicella‐zoster virus pneumonia co‐infected with Pneumocystis jirovecii
Authors: Zhang Qianwen , Liang Lingxiao , Liu Ailing , Zhou Dandan , Li Aijun 
Published: May 2022

Key messagePulmonary co‐infection with varicella‐zoster virus (VZV) and Pneumocystis jirovecii (PJ) is uncommon. This case describes computed tomography (CT) findings of VZV pneumonia co‐infected with PJ. Co‐infection of VZV and PJ pneumonia is possible in immunocompromised patients. The similarities in chest CT makes it difficult to differentiate VZV from PJ.
Decentralized adaptive output feedback dynamic surface control for stochastic nonstrict‐feedback interconnected nonlinear systems with actuator failures and input quantization via command filter
Authors: Zhang Tianping , Tang Hailin , Xia Xiaonan , Yi Yang 
Published: May 2022

AbstractIn this article, a new decentralized adaptive neural output feedback control scheme based on first‐order command filter is proposed for stochastic nonstrict‐feedback interconnected systems with prescribed performance, input quantization, actuator failures and unmodeled dynamics. The unknown smooth functions are eliminated by using the radial basis function neural networks. The immeasurable states in the system are estimated using the decentralized K‐filters, unmodeled dynamics is processed using dynamic signal, and the hyperbolic tangent function is applied to the construction of the prescribed performance function. The hysteretic quantizer and actuator failure are denoted in the form of linearization, and a smoothing function is introduced to compensate for the effects of quantization and bounded stuck faults. Based on the dynamic surface control (DSC) method and using the properties of Gaussian function to deal with stochastic nonstrict‐feedback interconnected systems, the first‐order command filter is used to replace the first‐order filter in the traditional DSC to eliminate the influence of filtering error on the systems, and an error compensation signal is introduced at the recursive each step of the design to construct a new error dynamic surface, which simplifies the derivation process and the design of the controller. Finally, the Lyapunov method is used to prove that all the signals in the whole controlled system are semiglobally uniformly ultimately bounded in probability and the tracking error is within the time‐varying constraint. The effectiveness of the proposed decentralized adaptive control method is verified by a numerical simulation and an example simulation.
About the special issue on: “Distributed Complex Systems: Governance, Engineering, and Maintenance”
Authors: Braione Pietro , Briola Daniela , De Angelis Guglielmo , Gallo Francesco , Poggi Francesco , Quattrocchi Giovanni 
Published: May 2022

AbstractThe volume at hand presents the Special Issue on “Distributed Complex Systems: Governance, Engineering, and Maintenance”. The Special Issue has been originally conceived within the context of the 2nd International Workshop on Governing Adaptive and Unplanned Systems of Systems (GAUSS 2020), one of the co‐located events of the 31st International Symposium on Software Reliability Engineering (ISSRE 2020). The authors of the best papers at GAUSS 2020 have been invited to submit an extended version of their previous work. In addition, the editors opened the submission also to all the other researches working on technical and managerial solution for governing Distributed Complex Systems. Ultimate objective of the editors with this Special Issue is to promote discussions focusing on anticipating, mitigating, or reacting to scenarios that were unplanned or under‐specified at design time.
SDK4ED: A platform for technical debt management
Authors: Ampatzoglou Apostolos , Chatzigeorgiou Alexander , Arvanitou Elvira Maria , Bibi Stamatia 
Published: May 2022

AbstractTechnical debt management is of paramount importance for the software industry, since maintenance is the costlier activity in the software development lifecycle. In this article, we present the SDK4ED platform that enables efficient technical debt management (i.e., measurement, evolution analysis, prevention, etc.) at the code level, and evaluate its capabilities in an industrial setting. The SDK4ED platform is the outcome of a 3‐year project, including several software industries. Since, the research rigor of the approaches that reside in SDK4ED have already been validated, in this work we focus: (a) on the presentation of the platform per se; (b) the evaluation of its industrial relevance; (c) the usability of the platform; as well as (d) the financial implications of its usage.
MuFBDTester: A mutation‐based test sequence generator for FBD programs implementing nuclear power plant software
Authors: Liu Lingjun , Jee Eunkyoung , Bae Doo‐Hwan 
Published: May 2022

SummaryFunction block diagram (FBD) is a standard programming language for programmable logic controllers (PLCs). PLCs have been widely used to develop safety‐critical systems such as nuclear reactor protection systems. It is crucial to test FBD programs for such systems effectively. This paper presents an automated test sequence generation approach using mutation testing techniques for FBD programs and the developed tool, MuFBDTester. Given an FBD program, MuFBDTester analyses the program and generates mutated programs based on mutation operators. MuFBDTester translates the given program and mutants into the input language of a satisfiability modulo theories (SMT) solver to derive a set of test sequences. The primary objective is to find the test data that can distinguish between the results of the given program and mutants. We conducted experiments with several examples including real industrial cases to evaluate the effectiveness and efficiency of our approach. With the control of test size, the results indicated that the mutation‐based test suites were statistically more effective at revealing artificial faults than structural coverage‐based test suites. Furthermore, the mutation‐based test suites detected more reproduced faults, found in industrial programs, than structural coverage‐based test suites. Compared to structural coverage‐based test generation time, the time required by MuFBDTester to generate one test sequence from industrial programs is approximately 1.3 times longer; however, it is considered to be worth paying the price for high effectiveness. Using MuFBDTester, the manual effort of creating test suites was significantly reduced from days to minutes due to automated test generation. MuFBDTester can provide highly effective test suites for FBD engineers.
Waste glass as a precursor in alkali‐activated materials: Mechanical, durability, and microstructural properties
Authors: Mobasheri Fatemeh , Mirvalad Sajjad , Shirzadi Javid Ali Akbar , Azizi Shahab , Ghoroqi Mahyar 
Published: May 2022

AbstractThe long‐term characteristics and durability of alkali‐activated mortars based on waste glass are crucial to better understand their performance in aggressive environments. In this regard, the performance of waste glass as a building material and its characteristics such as mechanical (compressive, flexural, and tensile strengths), durability (chloride migration coefficient, sulfate resistance, and drying shrinkage), and microstructural properties [x‐ray diffraction (XRD), Fourier transform infrared (FTIR), and scanning electron microscopy (SEM) with energy dispersive x‐ray analysis (SEM/EDX)] were evaluated. For this purpose, the specimens with different amounts of silica modulus and Na2O content were prepared. The specimens were cured at 95°C for 20 h and then kept at a relative humidity of 50% at room temperature until testing. The specimen with 10% Na2O and a silica modulus of 1.5 demonstrated the highest compressive, flexural, and tensile strengths. The specimens illustrated a lower chloride migration coefficient and lower expansion than the Portland cement one. By increasing both silica modulus and Na2O contents, the drying shrinkage of the specimens increased due to the presence of more free water. The microstructural results indicated that amorphous gels such as sodium aluminum silicate hydrate (N‐A‐S‐H) and sodium (calcium) silicate aluminum hydrate [N‐(C)‐A‐S‐H] were formed. The results of this study signify the utilization possibility of waste glass as an eco‐friendly material with desirable characteristics.
Black men doctoral scientists and engineers persisting: Peer support and racism in science and engineering
Authors: Watkins Shari Earnest , McGowan Brian L. 
Published: May 2022

AbstractDrawing on racial battle fatigue as theoretical framing and critical race methodology, we offer the counterstories of 16 Black men doctoral scientists and engineers who relied on same race peer support to successfully persist in their science and engineering (S&E) doctoral programs. Our analysis of narratives and interviews yielded three themes that illustrate the men's engagement with Black peers and how racism influences the types of peer relationships they formed in their S&E doctoral programs. Further, we describe three types of same race peer relationships that support Black men as they pursue S&E doctoral degrees. We underscore the salience of racism and recommend expanding research in S&E by: (1) including the lived experiences of Black men scientists and engineers in the scholarly literature, and (2) highlighting the importance of same race peer networks as academic, emotional, and social structures for Black men persisting in S&E. Within, we offer implications for science education, higher education, and S&E researchers interested in creating supportive S&E environments for Black men.