bluuebunny/crossref_metadata_2025_split huggingface dataset:
Directional Solidification of AlSi7Fe1 Alloy Under Forced Flow Conditions: Effect of Intermetallic Phase Precipitation and Dendrite Coarsening
Authors: Zhang Haijie , Wu Menghuai , Rodrigues Christian M. G. , Ludwig Andreas , Kharicha Abdellah 
Published: May 2021

Abstract
A forced flow was experimentally shown to influence the solidification microstructure of metal alloys by modifying the coarsening/ripening law. In some technical alloys (AlSi7Fe1), this flow effect can also be significantly suppressed due to the formation of intermetallic precipitates (β-Al5FeSi) that can block the flow in the mushy region. The forced flow was induced by a rotating magnetic field (RMF). Herein, a three-phase volume-average-based solidification model is introduced to reproduce the above experiment. The three phases are the melt, the primary solid phase of columnar dendrites, and the second solid phase of intermetallic precipitates. The dynamic precipitation of the intermetallic phase is modelled, and its blocking effect on the flow is considered by a modified permeability. Dendrite coarsening, which influences the permeability, is also considered. The RMF induces a strong azimuthal flow and a relatively weak meridional flow (Ekman effect) at the front of the mushy zone during unidirectional solidification. This forced flow reduces the mushy zone thickness, induces the central segregation channel, affects the distribution of the intermetallic precipitates, and influences dendrite coarsening, which in turn modifies the interdendritic flow. Both interdendritic flow and the microstructure formation are strongly coupled. The modelling results support the explanation of Steinbach and Ratke—the formed intermetallic precipitates (β-Al5FeSi) can block the interdendritic flow, and hence influence the coarsening law. The distribution of β-Al5FeSi is dominantly influenced by the flow-induced macrosegregation. The simulation results of the Si and Fe distribution across the sample section are compared with the experimental results, showing good simulation–experiment agreement.

Graphic Abstract
During alloy solidifications the flow can influence the mushy zone by inducing macrosegregation, modifying the solidification microstructure, and influencing the formation of intermetallic precipitates. The resulting microstructural features can in turn affect the melt flow by changing the flow intensity and flow pattern. A three-phase volume-average-based solidification model is introduced to study the flow-solidification interaction, and hence to improve the knowledge on the formation mechanism of intermetallics and their effect on solidification. (a) Schematic for the flow pattern and formation of different phases; (b) experiment–simulation comparison of macrosegregation (Fe) across the diameter of as-solidified sample.
Analysis of salts for use as support structure in metal material jetting
Authors: Kirchebner Benedikt , Rehekampff Christoph , Tröndle Martin , Lechner Philipp , Volk Wolfram 
Published: May 2021

AbstractMaterial jetting (MJT) is a category of additive manufacturing processes where the build material is deposited in the form of individual droplets. MJT has recently been expanded into the field of metal processing due to a potentially high printing speed at low equipment and raw material cost. For full 3D capability, support structures are needed that have to be removed after the print job. We examine water soluble salts and suitable nozzle materials to realise the printing of molten salt in a MJT process. Here, the wetting characteristics of the melt and nozzle are crucial because pronounced wetting is problematic for the ejection of droplets. A sessile-drop contact angle test stand was set up to evaluate the wetting characteristics of three salts or salt mixtures (NaCl, KCl–NaCl and NaCl–$${\hbox {Na}_{2}\hbox {CO}_{3}}$$

Na
2

CO
3

) on six different nozzle materials (various ceramics and graphite), i.e. potential nozzle materials. The results indicate a high wetting tendency of most of the examined samples with the exception of KCl-NaCl on graphite. Application of these materials on a MJT test stand confirm the feasibility of our findings.
Surgical considerations for atrial functional regurgitation of the mitral and tricuspid valves based on the etiological mechanism
Authors: Shibata Toshihiko , Takahashi Yosuke , Fujii Hiromichi , Morisaki Akimasa , Abe Yukio 
Published: May 2021

AbstractAtrial functional mitral regurgitation is a hot research topic in the field of mitral valve disease. Atrial functional mitral regurgitation is distinctly different from ventricular functional mitral regurgitation. The surgical indications for atrial functional mitral regurgitation have not been well established because of the small amount of evidence gathered to date. Mitral annular plication with an artificial ring is an essential surgical procedure because dilatation of the mitral valve annulus is a main factor underlying this pathology. Most of these cases can be treated by mitral annuloplasty alone. However, additional procedures, such as application of artificial chordae to the anterior leaflet for pseudo-prolapse, and posterior leaflet augmentation with a pericardial patch, are required in advanced cases with a giant left atrium and extremely enlarged mitral annulus. Chronic atrial fibrillation causes enlargement of the right and left atria. This pathology is a bilateral atrioventricular valve disease (dual-valve disease). Therefore, the conventional guidelines of single-valve disease should not be applied. Although atrial functional tricuspid regurgitation is underappreciated, tricuspid annuloplasty should be considered for most patients to prevent future regurgitation. In addition to the mitral and tricuspid valve procedure, integrated surgical management, including plication of the atrium and left appendage closure, is required. This review summarizes the current considerations of surgical treatment for atrial functional regurgitation of the mitral and tricuspid valves based on the etiological mechanism.
Interdicting facilities in tree networks
Authors: Fröhlich Nicolas , Ruzika Stefan 
Published: May 2021

AbstractThis article investigates a network interdiction problem on a tree network: given a subset of nodes chosen as facilities, an interdictor may dissect the network by removing a size-constrained set of edges, striving to worsen the established facilities best possible. Here, we consider a reachability objective function, which is closely related to the covering objective function: the interdictor aims to minimize the number of customers that are still connected to any facility after interdiction. For the covering objective on general graphs, this problem is known to be NP-complete (Fröhlich and Ruzika In: On the hardness of covering-interdiction problems. Theor. Comput. Sci., 2021). In contrast to this, we propose a polynomial-time solution algorithm to solve the problem on trees. The algorithm is based on dynamic programming and reveals the relation of this location-interdiction problem to knapsack-type problems. However, the input data for the dynamic program must be elaborately generated and relies on the theoretical results presented in this article. As a result, trees are the first known graph class that admits a polynomial-time algorithm for edge interdiction problems in the context of facility location planning.
Orthoptera assemblages of the relict meadows of the Szernye marsh area (West Ukraine: Transcarpathia)
Authors: Szanyi Szabolcs , Potish Ludvig , Rácz István András , Varga Zoltán , Nagy Antal 
Published: May 2021

AbstractOrthoptera assemblages were sampled between 2012 and 2014 on six grasslands in marginal part of the former Szernye Marsh (Bereg Lowland, Transcarpathia, West Ukraine). 24 species in 1306 individuals were observed which is about the half of the Orthoptera species known from the Bereg Lowland. The bulk of the assemblages is formed by generalist chortobiont species (62.5%), while thamnobionts, connected with tall forb and/or shrubby vegetation, also reach a relatively high frequency (29.1%). According to the biogeographical composition, the Euro-Siberian species were predominating (58.3%), combined with only scarce presence of West Palearctic and Mediterranean species. The multivariate analysis did not show any clear subdivision according to the a priori vegetation types with the exception of the xeric habitats. This assemblage type were characterised by a low species number (7–12) and very high frequency of one or at least two dominant species which were common in all types of studied habitats. Although their subdominant species differed from the other two assemlage types but they could not be referred as true character species. Thus the studied xeric habitats are not such true xeric grasslands as the sandy and saline grasslands of the Pannonian lowland. The main natural value of the area is preseved by semi-natural humide and transitional habitat types, which can be conserved by yearly alternating mowing and preserving the mosaic structure with some corridors among them.
Hierarchical Honeycomb-Structured Electret/Triboelectric Nanogenerator for Biomechanical and Morphing Wing Energy Harvesting
Authors: Tao Kai , Chen Zhensheng , Yi Haiping , Zhang Ruirong , Shen Qiang , Wu Jin , Tang Lihua , Fan Kangqi , Fu Yongqing , Miao Jianmin , Yuan Weizheng 
Published: May 2021

AbstractFlexible, compact, lightweight and sustainable power sources are indispensable for modern wearable and personal electronics and small-unmanned aerial vehicles (UAVs). Hierarchical honeycomb has the unique merits of compact mesostructures, excellent energy absorption properties and considerable weight to strength ratios. Herein, a honeycomb-inspired triboelectric nanogenerator (h-TENG) is proposed for biomechanical and UAV morphing wing energy harvesting based on contact triboelectrification wavy surface of cellular honeycomb structure. The wavy surface comprises a multilayered thin film structure (combining polyethylene terephthalate, silver nanowires and fluorinated ethylene propylene) fabricated through high-temperature thermoplastic molding and wafer-level bonding process. With superior synchronization of large amounts of energy generation units with honeycomb cells, the manufactured h-TENG prototype produces the maximum instantaneous open-circuit voltage, short-circuit current and output power of 1207 V, 68.5 μA and 12.4 mW, respectively, corresponding to a remarkable peak power density of 0.275 mW cm−3 (or 2.48 mW g−1) under hand pressing excitations. Attributed to the excellent elastic property of self-rebounding honeycomb structure, the flexible and transparent h-TENG can be easily pressed, bent and integrated into shoes for real-time insole plantar pressure mapping. The lightweight and compact h-TENG is further installed into a morphing wing of small UAVs for efficiently converting the flapping energy of ailerons into electricity for the first time. This research demonstrates this new conceptualizing single h-TENG device's versatility and viability for broad-range real-world application scenarios.
„Da baut sich was auf, da ist jemand, der ist verlässlich da, der hat auch Geld“ – Akteurskonstellationen, Handlungskoordination und Leistungen in fragilen organisationalen Strukturen am Beispiel der arbeitsorientierten Grundbildung
Authors: Koller Julia , Arbeiter Jana , Schemmann Michael 
Published: May 2021

ZusammenfassungDer Beitrag untersucht anhand der theoretischen Ansätze derEducational Governanceund des Neo-Institutionalismus die Steuerung in dem, bezüglich Finanzierung und Angebotsentwicklung fragilen Feld der arbeitsorientierten Grundbildung. Dabei wird fokussiert, wie soziale Ordnungen über die Koordination von Handlungen in verschiedenen Akteurskonstellationen pädagogische Leistung möglich machen. Konkret geht es darum, herauszuarbeiten, welche institutionellen und organisationalen Strukturen in der arbeitsorientierten Grundbildung erkennbar sind und welche Formen der Handlungskoordination zwischen Akteuren welche pädagogischen Leistungen zustande kommen lassen. Empirische Befunde weisen auf ein differenziertes und unterschiedlich dichtes Mehrebenensystem hin, in dem die Akteure über unterschiedliche Formen der Handlungskoordination Leistungen sichern und weiterentwickeln.
Surfactant-free synthesis of carbon-supported silver (Ag/C) nanobars as an efficient electrocatalyst for alcohol tolerance and oxidation of sodium borohydride in alkaline medium
Authors: Dey Santanu , Chakraborty Pradipta , Rana Dhiraj Kumar , Pramanik Subhamay , Basu Soumen 
Published: May 2021

AbstractWe have synthesized carbon-supported silver (Ag/C) nanobars by a simple surfactant-free hydrothermal method using glucose as the reducing reagent as well as the source of carbon in Ag/C nanobars. Physicochemical characterization of the materials was performed by X-ray Diffraction (XRD), field emission scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The XRD pattern confirmed the presence of a pure metallic silver phase. No carbon phase was detected, which indicates that the carbon exists mainly in the amorphous form. The electrocatalytic activity of Ag/C in different electrolyte solutions such as 0.5 M NaOH, 0.5 M NaOH + 1 M ethanol (EtOH), 0.5 M NaOH + 1 M ethylene glycol (EG), and 0.5 M NaOH + 0.01 M NaBH4 (sodium borohydride) was studied by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and chronoamperometry (CA) study. Alcohol tolerance of the catalysts was also established in the presence of ethanol and ethylene glycol. The forward-to-backward current ratio from cyclic voltammetry (CV) study of Ag/C-20 (20 h) in 0.5 M NaOH + 1 M ethanol solution at 100 mV s−1 scan rate is 4.13 times higher compared to that of Ag/C-5 (5 h). Hence, Ag/C-20 is a better candidate for the tolerance of ethanol. In the presence of ethylene glycol (1 M) in 0.5 M NaOH solution, it is obtained that the forward-to-backward current ratio at the same scan rate for Ag/C-20 is lower than that in the presence of ethanol. The durability of the catalyst was studied by chronoamperometry measurement. We studied the electrochemical kinetics of Ag/C catalysts for borohydride oxidation in an alkaline medium. The basic electrochemical results for borohydride oxidation show that Ag/C has very well strength and activity for direct borohydride oxidation in an alkaline medium. The reaction of borohydride oxidation with the contemporaneous BH4−. hydrolysis was noticed at the oxidized silver surface. Among all the synthesized Ag/C catalysts, Ag/C-20 exhibited the best electrocatalytic performance for borohydride oxidation in an alkaline medium. The activation energy and the number of exchange electrons at Ag/C-20 electrode surface for borohydride electro-oxidation were estimated as 57.2 kJ mol−1 and 2.27, respectively.
Disaster Behavioral Health Research Involving Military Facilities and Populations after Mass Violence: Insights from the 2013 Washington Navy Yard Shooting
Authors: Flynn Brian W , Vance Mary C , West James C , Morganstein Joshua C , Fullerton Carol S 
Published: May 2021

AbstractResearch on disaster behavioral health presents significant methodological challenges. Challenges are even more complex for research on mass violence events that involve military members, families, and communities, due to the cultural and logistical considerations of working with this population. The current article aims to inform and educate on this specialized area of research, by presenting a case study on the experience of designing and conducting disaster behavioral health research after a mass violence event in a military setting: the 2013 mass shooting at the Washington Navy Yard, in Washington, D.C. Using the case example, the authors explore methodological challenges and lessons learned from conducting research in this context, and provide guidance for future researchers.
Belief in conspiracy theories and attitudes toward political violence
Authors: Vegetti Federico , Littvay Levente 
Published: May 2021

AbstractIn the last decade, political protest events have been rising in Western democracies. At the same time, there has been a steady increase in the diffusion of conspiracy theories in political communication, a phenomenon that has captured the interest of scholars for its growing political relevance. However, while most research focuses on the reasons why citizens believe in conspiracies, studies looking at the political-behavioral implications of such beliefs, in particular their connection to political radicalism, have been more limited. In this paper, we investigate the association between people's belief in conspiracies and their propensity to endorse political violence or to legitimate radical political action. Building on pathway theories of radicalization, we argue that conspiracy theories provide narratives that might help people channel their feelings of resentment toward political targets, fueling radical attitudes. We provide some correlational evidence using survey data of US respondents collected on MTurk. We observe attitudes toward political violence using two multi-item batteries, one developed by us. Our results show that people who score higher on a scale of generic conspiracy belief are also more likely to endorse violent political actions.
Sequential impact of components of maternal and child health care services on the continuum of care in India
Authors: James K. S. , Mishra Udaya S. , Rinju  , Pallikadavath Saseendran 
Published: May 2021

AbstractThis paper examines the sequential impact of components of maternal and child health care on the continuum of care in India using data from the Indian National Family Health Surveys conducted in 2005–06 and 2015–16. Continuum of care (CoC) for maternal and child health is defined in this paper as the sequential uptake of three key maternal services (antenatal care, institutional delivery and postnatal care for the mother). Women who received all three services were classified as full CoC recipients. Characteristics odd ratios for achieving CoC were estimated by mother’s place of residence, household wealth status, mother’s education, birth order and child full vaccination. Odds ratios were computed to understand the relative impact of each preceding service utilization on the odds of subsequent service uptake. At national level, 30.5% and 55.5% of women achieved full CoC in 2005–06 and 2015–16, respectively, and the overall progress of CoC over the 10-year period was 25.5 percentage points, with significant variation across states and socioeconomic groups. Full CoC improved from 7.5% to 32.4% among the poorest women, whereas among the richest women it improved from 70.5% to 75.1%. Similarly, among uneducated women full CoC improved from 11.7% to 35.9% as against 75.1% to 80.5% among educated mothers over the same period. Furthermore, greater CoC was observed among parity one women. The conditionality between various components of CoC indicated that at national level the odds of having an institutional delivery with antenatal care were 9 times higher in the earlier period as against 4.5 times higher in the more recent period. Furthermore, women who had institutional deliveries complied more with mother’s postnatal care compared with women who did not have institutional deliveries. This again helps increase the likelihood of a child receiving full vaccination.
Extensive clonal propagation and resprouting drive the regeneration of a Brazilian dry forest
Authors: Vanderlei Renato Soares , Barros Maria Fabíola , Domingos-Melo Arthur , Alves Gilberto Dias , Silva Ana Beatriz , Tabarelli Marcelo 
Published: May 2021

AbstractWoody plant resprouting has received considerable attention in the last two decades as human disturbances continue to encroach on terrestrial ecosystems globally. We examined the regeneration mechanisms of a Caatinga dry forest in the context of slash-and-burn agriculture and resprouting ability of the local flora. We excavated two old fields (from 32) experiencing early forest regeneration dominated by the tree Pityrocarpa moniliformis (Fabaceae) to map clonal propagation and, in parallel, submitted 260 seedlings from 13 woody plant species to experimental clipping. What seemed to be ‘seedlings’ popping up around P. moniliformis stumps and remaining adults actually were condensed sets of root suckers connected via complex networks of long, ramified shallow horizontal roots without taproots. We mapped respectively 39 and 783 connected root suckers, which summed 96 m and 910 m in root length. Regarding the seedlings, 33% resprouted across nine species with resprouting rates varying between 5–100%. Seedling height before clipping positively influenced resprouting vigour. Our preliminary results suggest that the Caatinga dry forest supports a relatively high proportion of resprouting species, some of them able to clonally propagate and playing an ecosystem-level role by responding to early forest regeneration and high abundance/biomass across both regenerating and old-growth forests.
Oxidative stress induced by methomyl exposure reduces the quality of early embryo development in mice
Authors: He Daohong , Han Guobo , Zhang Xiaomeng , Sun Jingyu , Xu Yongnan , Jin Qingguo , Gao Qingshan 
Published: May 2021

SummaryMethomyl is a widely used carbamate insecticide and environmental oestrogen that has adverse effects on the reproductive system. However, there have been no reports on the effect of methomyl on early embryos in mammals. In this study, we explored the effect of methomyl exposure on the quality of early embryonic development in mice and the possible mechanisms. During in vitro culture, different concentrations of methomyl (10, 20, 30 and 35 μM) were added to mouse zygote medium. The results showed that methomyl had an adverse effect on early embryonic development. Compared with the control group, the addition of 30 μM methomyl significantly reduced the rate of early embryo blastocyst formation. Methomyl exposure can increase oxidative stress and impair mitochondrial function, which may be the cause of blastocyst formation. In addition, we found that methomyl exposure promoted apoptosis and autophagy in mouse blastocysts. The toxic effect of methomyl on early embryos may be the result of oxidative stress induction. Taken together, our results indicate that methomyl can cause embryonic development defects in mice, thereby reducing the quality of early embryo development.