bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Morphology for Ammonium Dinitramide on the Mechanical and Combustion Properties of Composite Propargyl‐terminated Copolyether Propellant
Authors: Gong Li , Li Yonghui , Guo Yanpei , Li Jianmin , Yang Rongjie 
Published: March 2020

AbstractBecause the isocyanate‐crosslinked copolyether binder system has poor compatibility with ammonium dinitramide (ADN), the click‐chemistry propargyl‐terminated ethylene oxide‐tetrahydrofuran copolyether (PTPET) binder cured by multi‐functional azide is introduced. In the solid propellant, the effects of spherical ADN and flaky ADN on the mechanical and combustion properties of PTPET solid propellants were investigated. The results show that the mechanical properties of the propellant prepared with the ADN‐spherical were comprehensively better than those of the propellant prepared with the ADN‐flaky. The ϵb/ϵm of the propellant with ADN‐spherical was obviously lower than that of the propellant with ADN‐flaky when the temperature at −40 °C. There was a sharp peak around −40 °C, followed by a broad peak, and a step rise near 40 °C about the DMA curves of both propellants. The burning rate measurement results showed that propellant prepared with flaky ADN had the higher burning rate at 3–17 MPa. The flame structures of both propellants showed stable combustion but the size of aluminum particles in flame zone for the propellant prepared with flaky ADN was larger.
Development and Characterization of a Photopolymeric Binder for Additively Manufactured Composite Solid Propellant Using Vibration Assisted Printing
Authors: McClain Monique S. , Afriat Aaron , Rhoads Jeffrey F. , Gunduz Ibrahim Emre , Son Steven F. 
Published: March 2020

AbstractAn emerging area of research in the energetic materials community is the development of new manufacturing methods, such as additive manufacturing (AM), that can be used to selectively deposit energetic materials into complex geometries, which provides more control over how the energetics perform during combustion. Although ammonium perchlorate (AP) composite propellant has been 3D printed at solids loadings that are comparable to traditional formulations (85 wt.%) with vibration assisted printing (VAP), traditional propellant binders such as hydroxyl terminated polybutadiene (HTPB) are poorly suited for 3D printing large or complex structures because propellant made with HTPB deforms easily under its own weight and isocyanates do not crosslink HTPB fast enough to facilitate rapid polymerization after deposition. Ultraviolet (UV) curable photopolymers have been used for many types of AM processes, such as stereolithography, and there is a variety of commercially available binders with customizable chemical and mechanical properties. However, little work has been done to characterize the optimal cure characteristics of UV curable binders that are compatible with composite propellants. Furthermore, it has also been speculated that aluminized propellants may not be amenable to UV curing since opaque particles impede UV transmission. In this work, the curing properties of a photopolymer that has similar characteristics to HTPB with AP and aluminum were quantified. The ingredients consisted of a polybutadiene urethane acrylate and hexanediol diacrylate (HDDA) polymer binder, which could be mixed in various ratios to control properties such as adhesion to particle surfaces and viscosity, as well as bisacylphosphine oxide (BAPO) which is a well‐known photoinitiator for deep curing in the coatings industry. The effect of wavelength, exposure time, and intensity on cure depth were quantified on the neat photopolymer. In addition, the effect of aluminum content (up to 20 %) on the cure depth of propellant with a solids loading of 85 wt.% was measured. It was shown that at higher intensities (∼20 mW/cm2), aluminized propellants could be cured to depths on the order of 1–2 mm, which is greater than the typical layer thickness of propellants printed via VAP (∼0.25 mm). In addition, it was shown that there were no visible interfaces in aluminized propellant (15 % aluminum) that was cured layer‐by‐layer. The approach taken could be applied to a wide range of other granular, opaque composite materials, such as metal, ceramic, and fibrous mixtures.
Decomposition‐based multiinnovation gradient identification algorithms for a special bilinear system based on its input‐output representation
Authors: Wang Longjin , Ji Yan , Yang Hualin , Xu Ling 
Published: March 2020

SummaryThis article considers the parameter estimation for a special bilinear system with colored noise. Its input‐output representation is derived by eliminating the state variables in the bilinear system. Based on the input‐output representation of the bilinear system, a multiinnovation generalized extended stochastic gradient (MI‐GESG) algorithm is proposed by using the multiinnovation identification theory. Furthermore, a decomposition‐based multiinnovation (ie, hierarchical multiinnovation) generalized extended stochastic gradient identification (H‐MI‐GESG) algorithm is derived to enhance the parameter estimation accuracy by using the hierarchical identification principle, and a GESG algorithm is presented for comparison. Compared with the existing identification algorithms for the bilinear system, the proposed MI‐GESG and H‐MI‐GESG algorithms can generate more accurate parameter estimation. Finally, a simulation example is provided to verify the effectiveness of the proposed algorithms.
Adaptive event‐triggered global fast finite‐time control for a class of uncertain nonlinear systems
Authors: Sun Wenjun , Zhao Junsheng , Sun Wei , Xia Jianwei , Sun Zong‐Yao 
Published: March 2020

SummaryThis article designs an adaptive event‐triggered controller to solve the problem of global finite‐time stabilization for a class of uncertain nonlinear systems. By using the symbol function technique, the event‐triggered error is completely compensated, the adaptive technique and the back‐stepping method are simultaneously applied to the controller design, and the new way of designing controller is completed on the basis of fast finite‐time stability theory. Subsequently, taking Lyapunov stability theorem into account, the system stability is proved, and the system is demonstrated by contradiction to be non‐zeno. Finally, giving a simulation example to display the feasibility of this method.
Modified instanton sum in QCD and higher-groups
Authors: Tanizaki Yuya , Ünsal Mithat 
Published: March 2020

Abstract
We consider the SU(N) Yang-Mills theory, whose topological sectors are restricted to the instanton number with integer multiples of p. We can formulate such a quantum field theory maintaining locality and unitarity, and the model contains both 2π-periodic scalar and 3-form gauge fields. This can be interpreted as coupling a topological theory to Yang-Mills theory, so the local dynamics becomes identical with that of pure Yang-Mills theory. The theory has not only ℤN 1-form symmetry but also ℤp 3-form symmetry, and we study the global nature of this theory from the recent ’t Hooft anomaly matching. The computation of ’t Hooft anomaly incorporates an intriguing higher-group structure. We also carefully examine that how such kinematical constraint is realized in the dynamics by using the large-N and also the reliable semiclassics on ℝ3 × S1, and we find that the topological susceptibility plays a role of the order parameter for the ℤp 3-form symmetry. Introducing a fermion in the fundamental or adjoint representation, we find that the chiral symmetry becomes larger than the usual case by ℤp, and it leads to the extra p vacua by discrete chiral symmetry breaking. No dynamical domain wall can interpolate those extra vacua since such objects must be charged under the 3-form symmetry in order to match the ’t Hooft anomaly.
A MATLAB code for topology optimization using the geometry projection method
Authors: Smith Hollis , Norato Julián A. 
Published: March 2020

AbstractThis work introduces a MATLAB code to perform the topology optimization of structures made of bars using the geometry projection method. The primary objective of this code is to make available to the structural optimization community a simple implementation of the geometry projection method that illustrates the formulation and makes it possible to easily and efficiently reproduce results. A guiding principle in writing the code is modularity, so that researchers can easily modify the program for their own purposes. Another goal is efficiency, for which extensive use of vectorization is made. This paper details the formulation of the geometry projection, discusses implementation aspects of the code, and demonstrates some of its capabilities by presenting several 2D and 3D compliance minimization examples.
Tod bei der Arbeit – eine Analyse tödlicher Arbeitsunfälle von 2005 bis 2016 im Obduktionsgut des Instituts für Rechtsmedizin in Frankfurt am Main
Authors: Dieterich C. , Herrmann E. , Parzeller M. 
Published: March 2020

Zusammenfassung
Hintergrund
Das genaue Wissen um die Umstände eines jeden tödlichen Arbeitsunfalls ist Voraussetzung für die Identifizierung von Unfallschwerpunkten und ermöglicht eine effektive Präventionsarbeit. Mit dieser rechtsmedizinischen Studie zum Arbeitsunfallgeschehen soll ein Beitrag dazu geleistet werden, die Zahl tödlicher Arbeitsunfälle in Deutschland zu senken.

Material und Methode
Zur Untersuchung kamen die tödlichen Arbeitsunfälle, die sich im Einzugsbereich des rechtsmedizinischen Instituts Frankfurt am Main in den Jahren von 2005 bis 2016 ereigneten. Ausgewertet wurden Obduktionsprotokolle sowie die dem Institut zur Verfügung gestellten staatsanwaltschaftlichen Ermittlungsakten.

Ergebnisse
Es fanden sich 87 tödliche Arbeitsunfälle in dem genannten Zwölfjahreszeitraum. Die Altersstruktur reichte vom jugendlichen Alter bis in das Rentenalter. Betroffen waren zum größten Teil männliche Arbeiter (96,6 %, p < 0,0001), verhältnismäßig häufig ausländischer Nationalität (34,5 %). Die meisten Unfälle ereigneten sich in der 2. Jahreshälfte (58,6 %), an Montagen (26,4 %), kurz vor und nach der Mittagspause. In 3 Fällen lag die Blutalkoholkonzentration über 0,5‰. Die Baubranche (55,2 %) war der unfallträchtigste Wirtschaftszweig. Der Absturz (28,7 %) war der häufigste Unfallmechanismus und das Polytrauma (39,1 %) gemeinsam mit dem Schädel-Hirn-Trauma (24,1 %) gemäß dem ISS die häufigste Todesursache.

Diskussion
Nach den Ergebnissen dieser Studie sollten Alter der Arbeiter sowie die Tages‑, Wochen- und Jahreszeit bei der Ausführung risikoreicher Arbeiten im Baugewerbe berücksichtigt werden. Besonderes Augenmerk sollten Arbeitgeber auf die Kontrolle von Sicherheitsvorkehrungen bei Arbeiten in der Höhe sowie auf die Durchsetzung der Helmpflicht gerade auch bei ausländischen Arbeitnehmern legen.
Intratympanic application of triamcinolone in sudden hearing loss—radiologic anatomy in cone beam CT and its’ correlation to clinical outcome
Authors: Roßberg Willi , Goetz Friedrich , Timm Max Eike , Lenarz Thomas , Helmstaedter Victor 
Published: March 2020

Abstract
Purpose
To evaluate temporal bone cone-beam CT in patients with idiopathic sudden sensorineural hearing loss (ISSNHL) being treated with primary and secondary intratympanic (IT) triamcinolone and to possibly correlate these results to the clinical outcome.

Methods
Retrospective analysis of patients treated with IT triamcinolone for ISSNHL at our department in 2018. Pre- and post-therapeutic audiologic examinations included four-tone average (FTA) at 0.5, 1, 2 and 3 kHz. Using a clinical questionnaire, pre-therapeutic CBCT scans were re-evaluated looking at items, which might interfere with adequate drug diffusion into the inner ear (e.g. bony overhangs or secondary membranes at the round or oval window).

Results
Thirty-one patients were included. Twenty-four (77%; group A) had experienced ineffective systemic steroid therapy before and seven (23%; group B) received primary IT injections. Four group A-patients (21%) and two group B-patients (33%) showed a post-therapeutic FTA improvement of more than 15 dB HL. Bony overhangs at the round window niche (RWN) were present in seven cases (26%), a secondary membrane at the RWN in four (15%) and soft tissue in eight (30%) cases, respectively.

Conclusion
Most patients present radiological findings in CBCT imaging, which might interfere with drug diffusion through the RW membrane. Interestingly, soft or bony tissue obstructing the RWN or the OWN was found in 50% of patients, who showed improvement of hearing. We conclude that radiologic ‘tiny’ findings are either clinically irrelevant or improvement in hearing is independent from intratympanic drug delivery.
Ischemic stroke and dose adjustment of oral Factor Xa inhibitors in patients with atrial fibrillation
Authors: Stoll Svenja , Macha Kosmas , Marsch Armin , Gerner Stefan T. , Siedler Gabriela , Fröhlich Kilian , Volbers Bastian , Strasser Erwin F. , Schwab Stefan , Kallmünzer Bernd 
Published: March 2020

Abstract
Background
Oral Factor Xa inhibitors for the prevention of stroke in atrial fibrillation require dose adjustment based on certain clinical criteria, but the off-label use of the reduced doses is common.

Methods
Data from an observational registry including patients admitted with acute cerebral ischemia while taking oral Factor Xa inhibitors for atrial fibrillation between April 2016 and December 2018 were investigated. The dose regimen of the Xa inhibitor was classified as “appropriate”, “underdosed” and “overdosed” in conformity with the European Medicines Agency labelling. The effect of underdosing on the functional factor Xa plasma level on admission, the clinical stroke severity and the functional outcome after 3 months were investigated.

Results
254 patients with cerebral ischemia while on Factor Xa inhibitors were included. The dose regimen of the Factor Xa inhibitor was appropriate in 166 patients (65%), underdosed in 67 patients (26%) and overdosed in 21 patients (8%). Underdosing was associated with female sex, diabetes mellitus and higher CHA2DS2–Vasc scores. Underdosing independently predicted lower anti-Xa plasma levels on admission [median 69.4 ng/ml (IQR 0.0–121.6) vs. 129.2 ng/ml (65.5–207.2); p < 0.001], was associated with higher NIHSS scores on admission [median 5 (IQR 1–10) vs. 3 (1–7); p = 0.041] and worse functional outcome after 3 months (favorable outcome 26.9% vs. 46.9%; p = 0.025).

Conclusion
One in three patients with ischemic stroke during treatment with oral Xa inhibitors used inappropriate dose regimens. Underdosing was associated with lower functional plasma levels, higher clinical stroke severity and worse functional outcome.
Prediction contribution of the cranial collateral circulation to the clinical and radiological outcome of ischemic stroke
Authors: Conrad Julian , Ertl Matthias , Oltmanns Meret H. , zu Eulenburg Peter 
Published: March 2020

AbstractBackground and AimThe extent of penumbra tissue and outcome in stroke patients depend on the collateral cranial vasculature. To provide optimal individualized care for stroke patients in the emergency room setting we investigated the predictive capability of a stringent evaluation of the collateral vessels in ischemic stroke on clinical outcome and infarct size.MethodsWe retrospectively studied uniform clinical and radiological data of 686 consecutive patients admitted to the emergency department with suspected acute ischemic stroke. Cranial collateral vasculature status was graded using the initial CT-angiography. Outcome was measured by mRS, NIHSS and final infarct size at hospital discharge. All data were used to build a linear regression model to predict the patients´ outcome.ResultsUnivariate and multivariate analyses showed significant effects of the whole brain collateral vessel score on all outcome variables. Atherosclerosis and piale collateral status were associated with the final infarct volume (FIV). Atherosclerosis and age were associated with the NIHSS at discharge. The presence of atherosclerosis, glucose level on admission and age were associated with the mRS at discharge. The multivariate models were able to predict 29% of the variance of the mRS at discharge, 24% of the variance in FIV and 17% of the variance of the NIHSS at discharge. The whole brain collateral status and the presence of atherosclerosis were the most relevant predictors for the clinical and radiological outcome.ConclusionThe whole brain collateral vasculature status is clearly associated with clinical and radiological outcome but in a multivariate model seems not sufficiently predictive for FIV, mRS and NIHSS outcome at discharge in non-preselected patients admitted to the emergency department with ischemic stroke.
Reduced cement volume does not affect screw stability in augmented pedicle screws
Authors: Weiser Lukas , Sellenschloh Kay , Püschel Klaus , Morlock Michael M. , Viezens Lennart , Lehmann Wolfgang , Huber Gerd 
Published: March 2020

Abstract
Purpose
Cement augmentation of pedicle screws is able to improve screw anchorage in osteoporotic vertebrae but is associated with a high complication rate. The goal of this study was to evaluate the impact of different cement volumes on pedicle screw fatigue strength.

Methods
Twenty-five human vertebral bodies (T12–L4) were collected from donors between 73 and 97 years of age. Bone density (BMD) was determined by quantitative computed tomography. Vertebral bodies were instrumented by conventional pedicle screws, and unilateral cement augmentation was performed. Thirteen vertebrae were augmented with a volume of 1 ml and twelve with a volume of 3 ml bone cement. A fatigue test was performed using a cranial–caudal sinusoidal, cyclic load (0.5 Hz) with increasing compression force (100 N + 0.1 N/cycles).

Results
The load to failure was 183.8 N for the non-augmented screws and was increased significantly to 268.1 N (p < 0.001) by cement augmentation. Augmentation with 1 ml bone cement increased the fatigue load by 41% while augmentation with 3 ml increased the failure load by 51% compared to the non-augmented screws, but there was no significant difference in fatigue loads between the specimens with screws augmented with 1 ml and screws augmented with 3 ml of bone cement (p = 0.504).

Conclusion
Cement augmentation significantly increases pedicle screw stability. The benefit of augmentation on screw anchorage was not significantly affected by reducing the applied volume of cement from 3 ml to 1 ml. Considering the high risk of cement leakage during augmentation, we recommend the usage of a reduced volume of 1 ml bone cement for each pedicle screw.

Graphic Abstract
These slides can be retrieved under Electronic Supplementary Material .
Simulation of hysteresis in soil–water retention with a correlation between the invading pressure to the governing effective flow area
Authors: Sattari Amir Shoarian , Siebelist Marlena , Toker Nabi Kartal , Wuttke Frank 
Published: March 2020

AbstractIn order to determine the soil–water retention (SWR) behavior of a particulate medium, the invading phase pressure in the inter-particle level is correlated to the governing effective pore area in the wetting and drying paths. In a three-phase medium that consists of air, wetting fluid and solids, the invading phase on the drying path is air, whereas on the wetting path the wetting fluid advances into the cavities. On a drying path where the area of a cavity is minimum, the air-entry pressure (AEP) of a pore throat is determined by numerically solving the Young–Laplace curvature equation. This can be done using the finite difference method and Newton–Raphson (Jacobian) approximation technique. Next, a relation between the pore area and the value of AEP is developed by varying the distance between solids around the pore throat. Similarly, the water-entry pressure (WEP) is correlated to a maximum pore area of cavity. After packing the particulate domain with the given particle size distribution (PSD) and void ratio values, the primary/main drying and wetting paths of the wetting fluid are simulated and the effect of hysteresis in SWR is shown. It is considered that the total suction equals to matric suction value and the water bridges between two adjacent particles are formed in the form of pendular rings. In this study, the considered material is non-plastic and the shrinkage and swelling during the drying and wetting phases or any change in pore structure are neglected. The simulation results are compared to experimentally determined as well as estimated data from the literature and a great agreement between the results is found, which offers a reliable way around conducting tedious and expensive SWR tests.
Anhaltende Haushaltsüberschüsse — Zeit für Steuersenkungen?
Authors: Homburg Stefan , Schratzenstaller Margit , Peichl Andreas , Fuest Clemens , Hüther Michael , Bach Stefan , Truger Achim 
Published: March 2020

ZusammenfassungDeutschland hat mittlerweile seit acht Jahren Überschüsse oder ausgeglichene öffentliche Haushalte zu verzeichnen. Entsprechend ist auch die Schuldenstandsquote so weit gesunken, dass das Maastricht-Kriterium wieder eingehalten wird. Diese durch einen langanhaltenden wirtschaftlichen Aufschwung begünstigte Entwicklung führt zu Streit darüber, wie die Überschüsse verwendet werden sollen. Einerseits gibt es einen Konsens, dass dringend Investitionen für die Klima- und Verkehrswende sowie für mehr Bildung und Innovationen benötigt werden, andererseits sehen einige die Wettbewerbsfähigkeit Deutschlands gefährdet, weil Unternehmen steuerlich überdurchschnittlich belastet seien. Die gute Haushaltslage könnte es aber auch erleichtern, eine grundlegende Reform des Steuer- und Abgabensystems durchzusetzen. Dabei sollte beachtet werden, dass Änderungen im Steuersystem ganz unterschiedliche Wirkungen auf die oberen oder die unteren Einkommensgruppen haben.
Sicherungsziele für die Rente: empirische Messung und Ergebnisse
Authors: Dudel Christian , Schmied Julian , Werding Martin 
Published: March 2020

ZusammenfassungDie Höhe gesetzlicher Altersrenten steht in Deutschland in den letzten Jahren wieder im Mittelpunkt öffentlicher Debatten. Überraschenderweise gibt es aber nur wenig Forschung zur Frage, wie hoch Renten eigentlich sein sollten. In diesem Beitrag werden empirisch fundierte Sicherungsziele aus der Literatur diskutiert und einige neue Berechnungen für Deutschland präsentiert. Die Sicherungsziele decken eine weite Bandbreite ab und entsprechen, gemessen am Einkommen vor dem Renteneintritt, Ersatzquoten von 33 % bis 50 %, wenn Armutsvermeidung das Ziel ist, und von 88 % bis 98 % zur Sicherung des Lebensstandards. Die in Deutschland durch gesetzliche Renten tatsächlich erreichten Ersatzquoten liegen in der Regel über den Werten zur Armutsvermeidung, aber unter der Lebensstandardsicherung.
Bahnsektor — Krise trotz erhöhter Finanzmittel
Authors: Böttger Christian 
Published: March 2020

ZusammenfassungAuf den ersten Blick ist die Lage für die Eisenbahn in Deutschland recht günstig. Die Bahn konnte in den letzten Jahren, trotz eher ungünstiger intermodaler Rahmenbedingungen, ihren Marktanteil leicht ausbauen. Angesichts der aktuell intensiven Debatte darüber, wie sich die Klimaziele erreichen lassen, genießt die Eisenbahn in Politik und Medien große Unterstützung. Der Bund hat die Mittel für die Schiene deutlich erhöht, aktuell zeigen sich jedoch ausgeprägte Krisensymptome: Die Zuverlässigkeit der Infrastruktur sinkt seit Jahren, die Gewinnmargen im Güterverkehr sind sehr niedrig, im Regionalverkehr sind die Margen aller Betreiber eingebrochen. Die Deutsche Bahn AG steckt in einer Führungs- und Finanzkrise.