bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigations on Guided Ultrasonic Wave Dispersion Behavior in Fiber Metal Laminates Using Finite Element Eigenvalue Analysis
Authors: Barth Tilmann , Wiedemann Johannes , Roloff Thomas , Hühne Christian , Sinapius Michael , Rauter Natalie 
Published: May 2023

AbstractComposite materials such as fiber metal laminates combine the advantages of metallic materials and fiber‐reinforced polymers. Hence, these materials are of great interest for thin‐walled structures in lightweight engineering. Due to the structure of these materials, damage to fiber metal laminate components occur more frequently inside the structure than with conventional materials. Since the detection of interlaminar damage is more complicated compared to external damage, it is one of the biggest challenges in the use of fiber metal laminates. One approach to detect this kinds of damage, is the use of guided ultrasonic waves, for example Lamb waves. To be able to perform such damage detection, knowledge about the propagation behavior of this kind of waves in fiber metal laminates is fundamental. Abrupt stiffness variations across the thickness of fiber metal laminates, resulting from the different material layers, lead to the question whether the known approaches for the propagation of guided ultrasonic waves in isotropic and transversely isotropic materials are applicable here. Therefore, the objective of this work is to investigate the propagation behavior of these guided ultrasonic waves in fiber‐metal laminates over large frequency ranges. For this purpose, dispersion relations from finite element simulations are compared with experimental data and numerical solutions based on the analytical framework. The investigations are carried out using a fiber metal laminate consisting of steel and carbon fiber‐reinforced polymers. Due to the orthotropy of the laminate, wave propagation in the fiber direction and perpendicular to it is considered. For the finite element simulations a linear two dimensional eigenvalue analysis is used. This method is especially suitable because it offers a very efficient modeling approach for this kind of application. The experimental data are based on measurements contained in previous publications by the authors. The comparison of the finite element simulations with the experimental data and the data from the analytical framework show that they are in good agreement. The results shown in this work serve to validate the numerical approach presented and allow for further, more complex simulations.
Comparing methods for permeability computation of porous materials and their limitations
Authors: Krach David , Steeb Holger 
Published: May 2023

AbstractEfficient numerical simulations of fluid flow on the pore scale allow for the numerical estimation of effective material properties of porous media, e.g. intrinsic permeability or tortuosity. These parameters are essential for various applications where hydro‐mechanical properties on larger scales have to be known. Numerical tools based intrinsically on pore scale simulations are known e.g. as Digital Rock Physics in geosciences and have even more and more replaced physical experiments. For these reasons, the validation of numerical methods as well as the establishment of clear limits regarding the application areas play an important role. Here, we compute single‐phase flow through a porous matrix, e.g. irregular sphere packings, sandstones, artificially created thin porous media, on the pore scale. Therefore we implement on the one hand a Smoothed Particle Hydrodynamics algorithm for solving the Navier‐Stokes equations and on the other hand a Finite Difference solver for the Stokes equations. Both methods work directly and seamlessly on voxel data of porous materials which are generated by µXRCT‐scans or by microfluidic experiments that have undergone segmentation and binarization. We compare both solvers from a parallel performance point of view as well as their results for flows in the Darcy regime. In addition, we investigate the limitations of the solvers using the example of a porous material whose pore geometry changes over time and precipitation affects the flow conditions.
On the optimal localization of pendulum impacts using a non‐contact acoustic array
Authors: Kocur Georg Karl , Markert Bernd 
Published: May 2023

AbstractThe presented work aims to adapt a Geiger‐based method and localize pendulum impacts applied on a rigid steel plate using the data set of a 112 microphone array. The advantage compared to measurements with piezoelectric sensors, where normally a number of sensors are involved, is the superior number of microphones. To solve the Geiger algorithm on the three‐dimensional domain, at least data from three sensors and the primary wave velocity are required (four equations). Moreover, if the system of equations is overdetermined, an error minimization can be performed, for example, with the least‐squares method. Since in this work the distance between array and plate is constant, the algorithm can be even reduced to a two‐dimensional problem (only three equations required). Indeed, the superior overdetermination of 112 microphone data allows to index the optimal data set by combing microphone data and thus achieve the best localization results for the optimal microphone. This study is relevant to the scientific community because it will allow uncontrolled events cracks or other damage to be localized with a great accuracy and reliability.
Migration and remodeling in cartilage replacement materials – an in‐vitro bioreactor study
Authors: Salazar Ortiz Rodrigo , Dursun Gözde , Topol Heiko , Markert Bernd , Stoffel Marcus 
Published: May 2023

AbstractThis article presents a bioreactor study that investigates the influence of mechanical stimulation on cell migration in a cartilage replacement material. The bioreactor has been designed to carry out dynamic stimulation of cell‐seeded scaffolds, and it consists of a loading mechanism, a force‐measuring device, and a biocompatible chamber. The stimulation of the samples was carried out inside a bioreactor chamber, which simulates physiological conditions that are found in vivo. Cell migration was determined using two collagen scaffolds, a part that mimics native tissue and a second cell‐free implant. The two parts were positioned in direct contact with each other, and the samples were then subjected to cyclic compression loading for a two‐week time frame. We determined the cell viability, the number of migrated cells, and the migration depth into the initially cell‐free part of the specimen. The results from the dynamic loading were compared with an unloaded control sample. The cell migration effect was determined for different collagen concentrations, which allowed us to observe the relationship between the collagen content and cellular activity. The present results were compared to results from the literature.
The cocontinuous morphology induced from the graphene nanosheets percolation network structures in the immiscible high density polyethylene/polyamide 6/graphene nanosheets composites
Authors: Huang Chien‐Lin , Yang Hao‐Ping , Ye Ji‐Yuan , Fan Yang‐Chun , Huang Shen‐Po 
Published: May 2023

AbstractThe addition of graphene nanosheets (GNSs) into immiscible polymer composites to induce the cocontinuous morphologies shows potential application in reinforced nanocomposites and conductive polymer nanocomposites. In this work, immiscible high density polyethylene (HDPE)/polyamide 6 (PA6)/GNS composites were prepared via melt mixing. The electrical and rheological property of HDPE/PA6 composites filled with various GNS contents according to different viscosity ratios and mixing orders were investigated to reveal the double percolation effect via percolation scaling laws, and compared with those of HDPE/GNS and PA6/GNS composites. The morphology and GNS dispersion state of HDPE/PA6/GNS composites were examined via transmission electron microscopy and scanning electron microscope. Most of the GNS were selectively located in the PA6 phase of HDPE/PA6/GNS composites. The GNS‐related network and mixing order played important roles in the cocontinuous morphology formation and performance of HDPE/PA6/GNS conductive composites. Moreover, the addition of GNS also affected the crystallization kinetics and mechanical property of HDPE/PA6/GNS composites.
Resilience strategies of Filipino irregular migrant domestic workers in the Netherlands during the COVID‐19 pandemic
Authors: Siruno Lalaine , Siegel Melissa 
Published: June 2023

AbstractCOVID‐19 has brought a combination of health, socioeconomic and protection challenges to migrants everywhere, and a common view is that these effects have been harshest for those already in vulnerable situations before the pandemic. However, the lived experiences of Filipino irregular migrant domestic workers (IMDWs) in the Netherlands point to a range of impacts instead of a homogenous one. Drawing on interviews and participant observations, we analyse three specific pandemic consequences: income and financial remittance volatility, dual country or transnational precarity and physical and migration status immobility. We then analyse the resilience strategies deployed by IMDWs to navigate through such impacts. While our focus is on the microlevel, we also highlight the vital importance of the responses by the community on the mesolevel, and the government on the macrolevel. Following this relational approach, we put forward a conceptualisation of individual resilience as the capacity to navigate the negative impacts of a shock or crisis to maintain, adapt, or transform valued functionings. We argue that IMDWs cultivate resilience despite their precarious legal status; however, the effectiveness of strategies is contingent on personal circumstances as well as the sociopolitical context wherein they are deployed. The paper contributes to the literature by providing a more nuanced picture of the impacts of and responses to COVID‐19 in relation to migrants with irregular status. The articulation of resilience in terms of valued functionings also paves the way for the advancement of the still nascent research agenda on migration andhumandevelopment.
Potential Impacts of Roe v. Wade repeal on Sexual and Reproductive Health in Sub‐Saharan Africa
Authors: Ekerin Olabode , Shomuyiwa Deborah Oluwaseun , Bayoh Alex Vandy Saffa , Atieno Ouma Sarah , Tejan Yusuf Sheku , Ndep Antor O. , Mengesha Dawit Tesfagiorgis , Lowe Mat 
Published: June 2023

AbstractThe United States (US) Supreme Court's decision to repeal Roe v. Wade has had significant implications for abortion care in the US, especially for emergency care. This ruling may also have an impact on sub‐Saharan Africa, where restrictive laws and policies limit women's access to safe and legal abortions. Sub‐Saharan Africa is the region with the highest rate of unwanted pregnancies and unsafe abortions, resulting in 15,000 preventable deaths annually. Although every country in sub‐Saharan Africa has at least one legal basis for abortion, they remain limited. In Nigeria, where 29% of pregnancies are unintended, 48% of these led to abortions, amounting to over 1.4 million abortions between 2015 and 2019. Unsafe abortions are prevalent in the region due to socioreligious stigma, particularly for unmarried women. Criminal charges can result from violating these limitations, with prison terms ranging from 3 to 14 years. The reversal of Roe v. Wade could have significant consequences in abortion‐related policies and politics in sub‐Saharan Africa, encouraging nations to adopt restrictive policies and legitimizing them. The landmark decision of Roe v. Wade may also impact the rate of unsafe abortions in the region, much like the US Mexico City Policy. With the high probability of foreign assistance funds for safe abortions depleted, sub‐Saharan African countries must prepare for this financial vacuum in health response. Therefore, the repeal of Roe v. Wade may lead to increased maternal morbidity and mortality in sub‐Saharan Africa, where access to safe and legal abortions is already limited.
A reliability analysis technique for complex systems with retaining fuzzy information
Authors: Zeng Yining , Sun Youchao 
Published: June 2023

AbstractThis paper proposed a method for the reliability analysis of systems characterized by fuzzy failure probabilities and intricate failure behaviors, while retaining the fuzzy information throughout the analysis process. Specifically, we introduced a combinational modeling method that integrates generalized stochastic Petri nets (GSPN) and dynamic fault trees (DFT) to capture the dynamic failure behaviors and address the limitations of DFT modeling. This combinational approach is capable of capturing more sophisticated failure behaviors, such as competing failures and global failure propagation patterns. Furthermore, we propose an Monte Carlo technique based on endpoint sampling to enable quantitative analysis of GSPN‐based composite models, which preserves the fuzzy fault information of the system. Finally, we demonstrate the effectiveness of the proposed method through an example of a flight control system.
Switching threshold‐based event‐triggered adaptive asymptotic tracking control for stochastic nonlinear systems with full‐state constraints
Authors: Du Yang , Zhu Shan‐Liang , Zhai Lian‐Lian , Han Yu‐Qun 
Published: June 2023

AbstractIn this article, the problem of event‐triggered adaptive asymptotic tracking control (ATC) for stochastic nonlinear systems with unknown control directions (UCDs) and full state constraints is concerned. It must be said that the controller design and system analysis is more complex and difficult since the existence of stochastic disturbances, UCDs and full state constraints simultaneously. By introducing the lower bound of the UCDs into the barrier Lyapunov functions, an event‐triggered adaptive MTN ATC scheme is proposed based on the boundary estimation method and a new event‐triggered control (ETC) strategy, which can achieve satisfactory asymptotic tracking performance and control performance of the system, while reduce the occupation of network resources. The simulation results not only verify the effectiveness of the proposed control scheme, but also present different tracking performances between three ETC strategies for comparison, further confirming the superiority of the proposed ETC strategy in achieving asymptotic tracking performance.
Airborne Methyl Jasmonate is Metabolized to Jasmonic Acid and 12‐Hydroxyjasmonic Acid, and Induces Jasmonate Biosynthesis in Marchantia polymorpha
Authors: Tsuzuki Hiromu , Kitaoka Naoki , Inoue Shiro , Takahashi Kosaku , Matsuura Hideyuki 
Published: June 2023

AbstractMethyl jasmonate (MeJA) is a volatile jasmonate compound commonly used to induce defense responses in spermatophytes. This study reports that airborne MeJA‐d3, deuterated MeJA, increases the levels of (dinor‐)12‐oxo‐phytodienoic acids [(dn‐)OPDAs] and jasmonic acid (JA) as well as JA‐d3 and 12‐hydroxyjasmonic acid‐d2 (12‐OH‐JA‐d2), MeJA‐d3 metabolites, in the model bryophyte Marchantia polymorpha. Enhancement of JA biosynthesis was substantiated by the expression of JA biosynthetic genes induced by airborne MeJA. Additionally, each of enantiomers, (+)‐MeJA and (−)‐MeJA, was observed to induce the accumulation of JA and (dn‐)OPDAs in M. polymorpha. This study demonstrates that airborne MeJA is metabolized to JA and 12‐OH‐JA, and induces JA biosynthesis in M. polymorpha. Moreover, the transient increase in endogenous JA level after airborne MeJA treatment provides concrete evidence that M. polymorpha biosynthesizes JA.
Designing High‐mass Loading 2D Ni‐TiO2/graphene Pellet Electrodes for Lithium Metal Batteries
Authors: Wang Gang , Zhang Qian , Zhang Kai , Gu Bo , Cheng Lin , Nie Qiaojun , Zhang Ming , Shen Zhongrong 
Published: June 2023

AbstractHigh conductivity and mass transfer channels of electrode materials with high mass loadings are the fundamental requirements for achieving high‐rate performance and high‐volume energy density. In this study, we investigated the method of constructing high‐mass loading pellet electrodes and their applications in lithium metal batteries from three different perspectives: selecting active electrode materials, designing the mass transfer porous structure, and constructing a conductive network. The three‐dimensional conductive network with porous structures provides the electrolyte's mass transfer channels and convenient charge transfer paths. The resulting pellet electrode demonstrates Young's modulus of 511 MPa under 44 % porosity, achieving satisfactory rate performance under mass loadings of 37.7 mg cm−2. After 200 cycles at the current density of 2.83 mA cm−2, it can maintain 56 % initial capacity, and the volume expansion is only 8.04 %. This study provides reference values for exploring and preparing high‐mass loading electrodes and the future design of solid‐state battery electrodes.
“Magic Numbers” in Self‐Faceting of Alcohol‐Doped Emulsion Droplets
Authors: Hacmon Sagi , Liber Shir R. , Shool Lee , Butenko Alexander V. , Atkins Ayelet , Sloutskin Eli 
Published: June 2023

AbstractOil‐in‐water emulsion droplets spontaneously adopt, below some temperature Td, counterintuitive faceted and complex non‐spherical shapes while remaining liquid. This transition is driven by a crystalline monolayer formed at the droplets' surface. Here, we show that ppm‐level doping of the droplet's bulk by long‐chain alcohols allows tuning Tdby >50 °C, implying formation of drastically different interfacial structures. Furthermore, “magic” alcohol chain lengths maximize Td. This we show to arise from self‐assembly of mixed alcohol:alkane interfacial structures of stacked alkane layers, co‐crystallized with hydrogen‐bonded alcohol dimers. These structures are accounted for theoretically and resolved by direct cryogenic transmission electron microscopy (cryoTEM), confirming the proposed structures. The discovered tunability of key properties of commonly‐used emulsions by minute concentrations of specific bulk additives should benefit these emulsions' technological applicability.
NiS/Cd0.6Zn0.4S Schottky Junction Bifunctional Photocatalyst for Sunlight‐Driven Highly Selective Catalytic Oxidation of Vanillyl Alcohol Towards Vanillin Coupled with Hydrogen Evolution Reaction
Authors: Du Rui , Wang Chuantao , Guo Li , Soomro Razium Ali , Xu Bin , Yang Chunming , Fu Feng , Wang Danjun 
Published: June 2023

AbstractSelective oxidation of biomass‐based molecules to high‐value chemicals in conjunction with hydrogen evolution reaction (HER) is an innovative photocatalysis strategy. The key challenge is to design bifunctional photocatalysts with suitable band structures, which can achieve highly efficient generation of high‐value chemicals and hydrogen. Herein, NiS/Cd0.6Zn0.4S Schottky junction bifunctional catalysts are constructed for sunlight‐driven catalytic vanillyl alcohol (VAL) selective oxidation towards vanillin (VN) coupling HER. At optimal conditions, the 8% NiS/Cd0.6Zn0.4S photocatalyst achieves high activity of VN production (3.75 mmol g−1 h−1) and HER (3.84 mmol g−1 h−1). It also exhibits remarkable VAL conversion (66.9%), VN yield (52.1%), and selectivity (77.8%). The photocatalytic oxidation of VAL proceeds a carbon‐centered radical mechanism via the cleavage of αC–H bond. Experimental results and theoretical calculations show that NiS with metallic properties enhances the electron transfer capability. Importantly, a Ni‐S‐Cd “electron bridge” formed at the interface of NiS/Cd0.6Zn0.4S further improves the separation/transfer of electrone/h+ pairs and also furnishes HER active sites due to its smaller the |ΔGH*| value, thereby resulting in a remarkably HER activity. This work sheds new light on the selective catalytic oxidation VAL to VN coupling HER, with a new pathway towards achieving its efficient HER efficiency.
All‐In‐One Evaporators for Efficient Solar‐Driven Simultaneous Collection of Water and Electricity
Authors: Ge Can , Xu Duo , Du Heng , Zhang Xiaohan , Song Zheheng , Zhao Haoyue , Chen Ze , Song Beibei , Shen Zhuoer , Gao Chong , Yan Guilong , Xu Weilin , Fang Jian 
Published: May 2023

AbstractThe shortage of fossil fuels and freshwater resources has become a serious global issue. Using solar energy to extract clean water with a photothermal conversion technology is a green and sustainable desalination method. Integrated electricity generation during the desalination process maximizes energy utilization efficiency. Herein, a solar‐driven steam and electricity generation (SSEG) system based on an all‐in‐one evaporator is prepared via a scalable technology. Carbon black is selected as the absorber for solar energy harvesting as well as the functional substance for simultaneous electricity generation. Fabric substrate with flexible structure, porous channel, and capillary effect is vital for directional brine supply, multiple solar absorption, and thermal management. The high evaporation rate (1.87 kg m−2 h−1) and voltage output (324 mV) can be achieved with an all‐in‐one device. The stable electricity output can be maintained over 40000 s. The SSEG performance remains constant after 15 operation cycles or 20 wash cycles. The integrated device balances excellent effectiveness and practicality, providing a viable path for clean desalination and electricity generation.
Remote Electronic Tuning of Chiral N‐Heterocyclic Carbenes
Authors: Inokuma Tsubasa , Yamada Ken‐ichi 
Published: May 2023

AbstractOur recent efforts to develop novel N‐Heterocyclic carbene (NHC)‐catalyzed asymmetric reactions are described. During our investigation for development of the acylation reactions via acylazoliums generated by the reactions of NHCs and α‐oxidized aldehydes, we have observed significant effects of substitution at a remote site of the carbene carbon of NHCs. In addition, we also observed a significant enhancement of the enantioselectivity by the addition of carboxylate anions. From this observation, we proposed a novel working hypothesis involving a formation of a complex of the substrate and additive to reinforce the recognition of the catalyst for enhancement of the catalytic performance of the asymmetric N‐heterocyclic carbene system. By applying this concept, we achieved the kinetic resolutions of both cyclic and acyclic alcohols in excellent enantioselectivities. The effects of the remote substitution were also observed in intramolecular Stetter reaction and intermolecular benzoin reaction. In these reactions, the comparison of the catalytic performance of the NHCs bearing variable remote substitutions provided insights into the reaction mechanism because the remote substitution tuned the electronic nature of NHCs without affecting the steric and electrostatic factors around the reaction site. We also developed an intramolecular benzoin condensation involving two aldehydes, which is challenging to realize. Using the substrates bearing proper protecting groups, we succeeded in the stereo divergent synthesis of a variety of inososes, which are important intermediates for the synthesis of biologically active cyclitols.