bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study on melamine/bentonite polyurethane porous composite foam: Pb2+ adsorption and mechanical properties
Authors: Li Ting‐Ting , Zhang Xiao , Wang Zhike , Ren Hai‐Tao , Peng Hao‐Kai , Shiu Bing‐Chiuan , Lou Ching‐Wen , Lin Jia‐Horng 
Published: February 2021

AbstractIn this paper, by adding melamine and bentonite to the polyurethane (PU) foam, a porous composite material with heavy metal adsorption properties is obtained. The cell size of the PU porous composite foam was affected by the addition of melamine and bentonite particles. With the increase of particles amount, the cell size decreased. The compression performance of the composite foam increased by 54% after adding 8 wt% melamine particles. The optimal adsorption conditions such as pH, adsorption time, and initial concentration of PU porous composites were also explored. Result shows that porous composite foam had a good removal effect on Pb2+. Moreover, the Langmuir model, the Freundlich model, and the adsorption kinetic model are used to evaluate the adsorption capacity of the porous composite foam. It is of great significance to obtain porous composite with good heavy‐metal adsorption and high‐strength performance.
Viscoelastic properties and flow instabilities of aqueous suspensions of cellulosic fibers: Effects of a gelation agent on dispersion, rheology, and flow stability
Authors: He Jing , Lee Stephanie S. , Colakyan Manuk , Kalyon Dilhan M. 
Published: February 2021

AbstractProcessing of concentrated lignocellulosic biomass suspensions typically involves the conversion of the cellulose into sugars and sugars into ethanol. Biomass is usually pretreated via methods like comminution or steam explosion to form fine cellulosic fibers to be dispersed into an aqueous phase for further treatment. The resulting cellulose suspensions need to be pressurized and pumped into and out of various processing vessels without allowing the development of flow instabilities that are typically associated with “demixing”, that is, the segregation of the cellulosic biomass from the aqueous phase via the formation of mats of cellulosic fibers and the filtration of the aqueous phase. Such demixing can prevent continuous processing at high rates. Here, the development of flow instabilities via the demixing effect for cellulose suspensions is demonstrated using capillary and compressive squeeze flows. It is shown that the use of a gelation agent, hydroxypropyl guar gum, at the critical concentration of 0.5 wt% or higher significantly affects the viscoelastic material functions of cellulosic suspensions, improves the dispersive mixing of the fibers within the aqueous phase, and results in the elimination of the flow instabilities and associated demixing effects that are ubiquitously observed during the pressurization and processing of cellulosic suspensions.
Modeling Microstructural Effects on Heterogeneous Temperature Fields within Polycrystalline Explosives
Authors: Mohan Nisha , Luscher Darby J. , Cawkwell Marc J. , Addessio F. L. , Ramos Kyle J. 
Published: February 2021

AbstractThe paper addresses the role of crystal anisotropy on the evolution of heterogeneous temperature fields in plastic‐bonded explosives (PBXs) under conditions of weak shock. The modeling approach is based on simplified idealizations of PBX microstructure including RDX grains and estane binder regions subjected to velocity boundary conditions representative of impact conditions in situ. The constitutive description of the microstructure constituents includes a dislocation‐based, anisotropic, single crystal plasticity model for the explosive grains and a linear viscoelastic model to represent the estane binder. Large suites of simulations were used to systematically study the correlation in heating of the grains with local wave dynamics, crystal orientation, and the microstructural neighborhood. These correlations were identified through the selection of characteristics of crystal anisotropy including oriented wave speeds and Taylor factor. A key observation is that the wave dispersion within a certain distance from the impact interface plays a dominant role in the temperature field. Beyond this distance, individual crystal orientations play a more dominant role, but cannot entirely account for the observed heterogeneity without consideration of the local microstructure neighborhood.
Ansatz der Drehbehinderung aus Koppelpfetten mit dünnwandigen kaltgeformten Z‐Profilen
Authors: Hennes Philipp , Laumann Jörg 
Published: February 2021

AbstractFür eine wirtschaftliche Bemessung von Hallenriegeln und Rahmen ist die Berücksichtigung der Drehbettung aus der Dacheindeckung sinnvoll. Derzeit existieren keine geeigneten Grundlagen zum Ansatz von kaltgeformten Dachpfetten und deren Anschlusssteifigkeit. Experimentelle und numerische Untersuchungen an Koppelpfetten mit dünnwandigen kaltgeformten Z‐Querschnitten zeigen, dass die Anschlusssteifigkeit für die Berücksichtigung der drehstabilisierenden Wirkung nicht vernachlässigbar ist. Zur Bestimmung dieser Anschlusssteifigkeit für dünnwandige kaltgeformte Z‐Pfetten werden unterschiedliche Profilhöhen und Blechdicken untersucht. Aus der Momenten‐Verdrehungsbeziehung lässt sich die Anschlusssteifigkeit CϑA,k als Sekantensteifigkeit unter Berücksichtigung nichtlinearer Verformungen bestimmen. Auf Basis der Untersuchungen werden Angaben zur Anschlusssteifigkeit von ausgewählten dünnwandigen Pfetten zur Verfügung gestellt, die bei den üblichen Berechnungsmethoden nach Eurocode 3 zur Berücksichtigung der Drehbettung verwendet werden können. Es wird gezeigt, dass zwischen der Anschlusssteifigkeit und der Steifigkeit der Einzelkomponenten, wie Lochleibung und Abscheren der Verbindungsmittel sowie Verformung des Pfettenhalters, Korrelationen bestehen. Zur Bestimmung einer allgemeingültigen Gleichung sind dennoch weiterführende Untersuchungen mit einem breiten Parameterbereich erforderlich.
Impact Propagation in Airport Systems
Authors: Köpke Corinna , Srivastava Kushal , König Louis , Miller Natalie , Fehling-Kaschek Mirjam , Burke Kelly , Mangini Matteo , Praça Isabel , Canito Alda , Carvalho Olga , Apolinário Filipe , Escravana Nelson , Carstengerdes Nils , Stelkens-Kobsch Tim 
Published: February 2021

AbstractThe effective protection of critical infrastructure against cyber and physical security threats involves many different steps from initially the identification of risks to finally the implementation of counter measures in the infrastructure. To derive counter measures and to come to intelligent decisions facing the identified risks, the impact calculation plays a central role. The impact of a specific threat can propagate through the systems of the infrastructure and thus needs to be analysed carefully. In this paper, the role of impact propagation of cyber-physical threats for infrastructure protection is discussed, exemplified for airport systems. In the ongoing EU-H2020 project SATIE (Security of Air Transport Infrastructure of Europe) a toolkit is developed containing two tools for impact propagation, namely the Business Impact Assessment (BIA) and the Impact Propagation Simulation (IPS). Both tools are described and for a small test case the propagation of a cyber threat and the transformation into a physical threat is demonstrated in a network representation as well as an agent-based model of the airport’s systems employing the IPS.
Most general theory of 3d gravity: covariant phase space, dual diffeomorphisms, and more
Authors: Geiller Marc , Goeller Christophe , Merino Nelson 
Published: February 2021

Abstract
We show that the phase space of three-dimensional gravity contains two layers of dualities: between diffeomorphisms and a notion of “dual diffeomorphisms” on the one hand, and between first order curvature and torsion on the other hand. This is most elegantly revealed and understood when studying the most general Lorentz-invariant first order theory in connection and triad variables, described by the so-called Mielke-Baekler Lagrangian. By analyzing the quasi-local symmetries of this theory in the covariant phase space formalism, we show that in each sector of the torsion/curvature duality there exists a well-defined notion of dual diffeomorphism, which furthermore follows uniquely from the Sugawara construction. Together with the usual diffeomorphisms, these duals form at finite distance, without any boundary conditions, and for any sign of the cosmological constant, a centreless double Virasoro algebra which in the flat case reduces to the BMS3 algebra. These algebras can then be centrally-extended via the twisted Sugawara construction. This shows that the celebrated results about asymptotic symmetry algebras are actually generic features of three-dimensional gravity at any finite distance. They are however only revealed when working in first order connection and triad variables, and a priori inaccessible from Chern-Simons theory. As a bonus, we study the second order equations of motion of the Mielke-Baekler model, as well as the on-shell Lagrangian. This reveals the duality between Riemannian metric and teleparallel gravity, and a new candidate theory for three-dimensional massive gravity which we call teleparallel topologically massive gravity.
The Coulomb and Higgs branches of $$ \mathcal{N} $$ = 1 theories of Class $$ {\mathcal{S}}_k $$
Authors: Bourton Thomas , Pini Alessandro , Pomoni Elli 
Published: February 2021

Abstract
Even though for generic $$ \mathcal{N} $$
N
= 1 theories it is not possible to separate distinct branches of supersymmetric vacua, in this paper we study a special class of $$ \mathcal{N} $$
N
= 1 SCFTs, these of Class $$ {\mathcal{S}}_k $$

S
k

for which it is possible to define Coulomb and Higgs branches precisely as for the $$ \mathcal{N} $$
N
= 2 theories of Class $$ \mathcal{S} $$
S
from which they descend. We study the BPS operators that parameterise these branches of vacua using the different limits of the superconformal index as well as the Coulomb and Higgs branch Hilbert Series. Finally, with the tools we have developed, we provide a check that six dimensional (1, 1) Little String theory can be deconstructed from a toroidal quiver in Class $$ {\mathcal{S}}_k $$

S
k

.
Exactly solvable single-trace four point correlators in χCFT4
Authors: Derkachov Sergey , Olivucci Enrico 
Published: February 2021

Abstract
In this paper we study a wide class of planar single-trace four point correlators in the chiral conformal field theory (χCFT4) arising as a double scaling limit of the γ-deformed $$ \mathcal{N} $$
N
= 4 SYM theory. In the planar (t’Hooft) limit, each of such correlators is described by a single Feynman integral having the bulk topology of a square lattice “fishnet” and/or of an honeycomb lattice of Yukawa vertices. The computation of this class of Feynmann integrals at any loop is achieved by means of an exactly-solvable spin chain magnet with SO(1, 5) symmetry. In this paper we explain in detail the solution of the magnet model as presented in our recent letter and we obtain a general formula for the representation of the Feynman integrals over the spectrum of the separated variables of the magnet, for any number of scalar and fermionic fields in the corresponding correlator. For the particular choice of scalar fields only, our formula reproduces the conjecture of B. Basso and L. Dixon for the fishnet integrals.
Loops in dS/CFT
Authors: Heckelbacher Till , Sachs Ivo 
Published: February 2021

Abstract
We consider the semi-classical expansion of the Bunch-Davies wavefunction with future boundary condition in position space for a real scalar field, conformally coupled to a classical de Sitter background in the expanding Poincaré patch with quartic selfinteraction. In the future boundary limit the wave function takes the form of the generating functional of a Euclidean conformal field theory for which we calculate the anomalous dimensions of the double trace deformations at one loop order using results obtained from Euclidean Anti de Sitter space. We find analytic expressions for some subleading twist operators and an algorithm to obtain expressions for general twist.
Effective action of type II superstring theories at order α′3: NS-NS couplings
Authors: Garousi Mohammad R. 
Published: February 2021

Abstract
Recently, it has been shown that the minimum number of gauge invariant couplings for B-field, metric and dilaton at order α′3 is 872. These couplings, in a particular scheme, appear in 55 different structures. In this paper, up to an overall factor, we fix all parameters in type II supertirng theories by requiring the reduction of the couplings on a circle to be invariant under T-duality transformations. We find that there are 445 non-zero couplings which appear in 15 different structures. The couplings are fully consistent with the partial couplings that have been found in the literature by the four-point S-matrix element and by the non-linear Sigma model methods.
Does SUSY have friends? A new approach for LHC event analysis
Authors: Mullin Anna , Nicholls Stuart , Pacey Holly , Parker Michael , White Martin , Williams Sarah 
Published: February 2021

Abstract
We present a novel technique for the analysis of proton-proton collision events from the ATLAS and CMS experiments at the Large Hadron Collider. For a given final state and choice of kinematic variables, we build a graph network in which the individual events appear as weighted nodes, with edges between events defined by their distance in kinematic space. We then show that it is possible to calculate local metrics of the network that serve as event-by-event variables for separating signal and background processes, and we evaluate these for a number of different networks that are derived from different distance metrics. Using a supersymmetric electroweakino and stop production as examples, we construct prototype analyses that take account of the fact that the number of simulated Monte Carlo events used in an LHC analysis may differ from the number of events expected in the LHC dataset, allowing an accurate background estimate for a particle search at the LHC to be derived. For the electroweakino example, we show that the use of network variables outperforms both cut-and-count analyses that use the original variables and a boosted decision tree trained on the original variables. The stop example, deliberately chosen to be difficult to exclude due its kinematic similarity with the top background, demonstrates that network variables are not automatically sensitive to BSM physics. Nevertheless, we identify local network metrics that show promise if their robustness under certain assumptions of node-weighted networks can be confirmed.
Medizinischer Kinderschutz während des Corona-Lockdowns
Authors: Heimann T. , Ewert J. , Metzner F. , Sigmund F. , Jud A. , Pawils S. 
Published: February 2021

Zusammenfassung
Hintergrund
Es gibt Anhaltspunkte dafür, dass die Gefahr von Kindesmisshandlung, sexuellem Kindesmissbrauch und Vernachlässigung während der strengen Kontaktbeschränkungen im pandemiebedingten Lockdown zugenommen hat, während der Wegfall der gewohnten Mechanismen zur sozialen Kontrolle mutmaßlich zu einer Zunahme des Dunkelfelds geführt hat.

Ziel der Arbeit
Anhand der Kinderschutzfallzahlen und -qualitäten deutscher Kinderkliniken und Kinderschutzambulanzen sollen Aussagen über Häufigkeit und Schwere vermuteter Kindeswohlgefährdung während des pandemiebedingten Lockdowns getroffen werden.

Methoden
Im Mai 2020 erfolgte eine Onlinebefragung mit Items a) zur Beschreibung der Institution, b) zur nach Alter, Gewaltform und Schweregrad differenzierten Anzahl von Kinderschutzfällen in März/April 2019 und 2020 sowie c) zu Besonderheiten und Ideen für den Kinderschutz während der Pandemie.

Ergebnisse
In einer Vollerhebung wurden 343 Kinderkliniken und medizinische Kinderschutzambulanzen zur Onlinebefragung eingeladen; die Teilnahmequote lag bei 46 %. Es gaben 81 Einrichtungen Gesamtfallzahlen für März/April 2019 und März/April 2020 an. Bei den Ambulanzen konnte ein Rückgang von 454 auf 387 Fälle (−15 %) verzeichnet werden, bei den Kinderschutzgruppen von 307 auf 246 (−20 %). Hinsichtlich der Altersgruppen und der Formen der Gefährdung fanden sich keine signifikanten Unterschiede.

Schlussfolgerung
Die Untersuchung beschreibt einen Rückgang der absoluten Fallzahlen im medizinischen Kinderschutz während des Lockdowns im März und im April 2020. Dieses Ergebnis stützt die Vermutung, dass das Dunkelfeld gefährdeter Kinder weiter gestiegen sein könnte. Weitere Datenerhebungen nach dem Lockdown werden die längerfristigen Auswirkungen besser bewerten können.
Klinische Umsetzbarkeit der kognitiven Screeningbatterie BICAMS bei Patienten mit Multipler Sklerose: Ergebnisse der Machbarkeitsstudie in Deutschland
Authors: Penner Iris﻿-﻿Katharina , Filser Melanie , Bätge Sharon Jean , Renner Alina , Ullrich Sebastian , Lassek Christoph 
Published: February 2021

Zusammenfassung
Hintergrund
Patienten mit Multipler Sklerose (MS) leiden in 40–70 % der Fälle unter kognitiven Störungen. Der kognitive Status gilt erwiesenermaßen als Prädiktor für Berufsfähigkeit und frühzeitige Berentung. Eine regelmäßige Erfassung der kognitiven Leistungsfähigkeit ist somit dringend indiziert.

Zielsetzung
Die deutsche Fassung der international empfohlenen BICAMS (Brief International Cognitive Assessment for Multiple Sclerosis) -Batterie wurde auf Praktikabilität in der klinischen Routine neurologischer Praxen in Deutschland multizentrisch überprüft.

Material und Methoden
Medizinische Fachangestellte (MFAs) wurden hinsichtlich der Durchführung und Auswertung von BICAMS geschult. Alle ausgewerteten Testbögen wurden von unabhängigen neuropsychologischen Experten überprüft.

Ergebnisse
Insgesamt 1606 BICAMS-Datensätze wurden in 65 Zentren erhoben. Von diesen konnten 1573 analysiert werden. 49,7 % der erhobenen Datensätze wurden inklusive aller Auswerteschritte korrekt durchgeführt. Bei den anderen 50,3 % fanden sich Durchführungs‑, Auswerte- oder Transformationsfehler. Nach Bereinigung der Stichprobe durch fehlerbehaftete Fälle ergaben sich Werte der Interrater-Reliabilität pro Testverfahren in Höhe von ICC $$\geq$$
≥
0,953.

Diskussion
Grundsätzlich ist BICAMS für den Einsatz im klinischen Alltag sehr zu empfehlen. Es bleibt allerdings zu betonen, dass obgleich die Interrater-Reliabilität für die final bereinigte Stichprobe sehr hoch war, im Gesamtdatensatz 50,3 % Durchführungs‑, Auswerte- oder Transformationsfehler gefunden wurden. Daraus lässt sich die Notwendigkeit ableiten, nichtpsychologisches Personal noch eingehender in der Anwendung und Auswertung von BICAMS durch Experten zu schulen und zu supervidieren.
An experimental investigation on tool wear behaviour of uncoated and coated micro-tools in micro-milling of graphene-reinforced polymer nanocomposites
Authors: Shakoori Niusha , Fu Guoyu , Le Bao , Khaliq Jibran , Jiang Long , Huo Dehong , Shyha Islam 
Published: February 2021

AbstractNanomaterials such as graphene have been added to various matrices to enhance mechanical, thermal and electrical properties for various applications requiring intricate designs at the micro-scale. At this scale, mechanical micro-machining is utilised as post-processing to achieve high surface quality and dimensional accuracy while still maintaining high productivity. Therefore, in this study, the machinability of polymer nanocomposites in micro-scale (micro-machinability) is investigated. Graphene (0.3 wt%)-reinforced epoxy nanocomposites were fabricated using traditional solution mixing and moulding. The samples were then subjected to micro-milling at various cutting speeds using three different micro-tools, including uncoated, diamond and diamond-like carbon (DLC) tools. Mechanical and thermal properties of nanocomposite were also used to support the discussions. The result indicates that the DLC-coated tool shows better performance than the other tools for less tool wear, improved surface quality and less cutting forces.
Duality Hierarchies and Differential Graded Lie Algebras
Authors: Bonezzi Roberto , Hohm Olaf 
Published: February 2021

AbstractThe gauge theories underlying gauged supergravity and exceptional field theory are based on tensor hierarchies: generalizations of Yang-Mills theory utilizing algebraic structures that generalize Lie algebras and, as a consequence, require higher-form gauge fields. Recently, we proposed that the algebraic structure allowing for consistent tensor hierarchies is axiomatized by ‘infinity-enhanced Leibniz algebras’ defined on graded vector spaces generalizing Leibniz algebras. It was subsequently shown that, upon appending additional vector spaces, this structure can be reinterpreted as a differential graded Lie algebra. We use this observation to streamline the construction of general tensor hierarchies, and we formulate dynamics in terms of a hierarchy of first-order duality relations, including scalar fields with a potential.
Family feud: permanent group splitting in a highly philopatric mammal, the killer whale (Orcinus orca)
Authors: Stredulinsky Eva H. , Darimont Chris T. , Barrett-Lennard Lance , Ellis Graeme M. , Ford John K. B. 
Published: February 2021

Abstract
For animals that tend to remain with their natal group rather than individually disperse, group sizes may become too large to benefit individual fitness. In such cases, group splitting (or fission) allows philopatric animals to form more optimal group sizes without sacrificing all familiar social relationships. Although permanent group splitting is observed in many mammals, it occurs relatively infrequently. Here, we use combined generalized modeling and machine learning approaches to provide a comprehensive examination of group splitting in a population of killer whales (Orcinus orca) that occurred over three decades. Fission occurred both along and across maternal lines, where animals dispersed in parallel with their closest maternal kin. Group splitting was more common: (1) in larger natal groups, (2) when the common maternal ancestor was no longer alive, and (3) among groups with greater substructuring. The death of a matriarch did not appear to immediately trigger splitting. Our data suggest intragroup competition for food, leadership experience and kinship are important factors that influence group splitting in this population. Our approach provides a foundation for future studies to examine the dynamics and consequences of matrilineal fission in killer whales and other taxa.

Significance statement
Group living among mammals often involves long-term social affiliation, strengthened by kinship and cooperative behaviours. As such, changes in group membership may have significant consequences for individuals’ fitness and a population’s genetic structure. Permanent group splitting is a complex and relatively rare phenomenon that has yet to be examined in detail in killer whales. In the context of a growing population, in which offspring of both sexes remain with their mothers for life, we provide the first in-depth examination of group splitting in killer whales, where splitting occurs both along and across maternal lines. We also undertake the first comprehensive assessment of how killer whale intragroup cohesion is influenced by both external and internal factors, including group structure, population and group demography, and resource abundance.