bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rapeseed oil gallate-amide-urethane coating material: Synthesis and evaluation of coating properties
Authors: Alam Manawwer , Altaf Mohammad , Ahmad Naushad 
Published: February 2022

Abstract
The present manuscript describes the synthesis of urethane (ROGAU) coating material from Rapeseed oil (RO), Gallic acid (GA) and Toluylene-2,4-diisocyanate [TDI], for the first time. The reaction was accomplished in the following steps: (i) amidation of RO, producing diol fatty amide, HERA, followed by (ii) gallation reaction of HERA with GA, resulting in RO-based gallate amide (ROGA). The structural elucidation by FTIR and NMR confirmed the insertion of amide and ester moieties in the ROGA backbone. To add applicational value to ROGA, it was then derivatized by urethanation reaction with TDI to develop ambient temperature-cured ROGAU, as a corrosion protective coating material. ROGAU coatings were scratch resistant, well-adherent, and flexible to a considerable extent and showed good corrosion resistance performance toward saline medium (3.5 wt% NaCl). ROGAU coatings can be safely used up to 200°C.
A Novel architecture for low-jitter multi-GHz frequency synthesis
Authors: Herzel Frank , Mausolf Thomas , Fischer Gunter 
Published: February 2022

Abstract
A phase-locked loop (PLL) cascade driven by a crystal oscillator and a free running dielectric resonator oscillator (DRO) is proposed. For minimizing phase noise, spurious tones and jitter, a programmable PLL1 in the lower GHz range is used to drive a millimeter-wave (mmW) PLL2 with a fixed frequency multiplication factor. The phase noise analysis results in two optimum bandwidths of the two PLLs for the lowest output jitter of the cascade. Phase noise and spurious tones (spurs) in PLL1 are further reduced by dividing the output frequency of PLL1 and up-converting it by means of a single-sideband (SSB) mixer driven by the DRO. By including the SSB mixer in the feedback loop of PLL1 manual tuning of the DRO is avoided, and a low-noise free running DRO can be employed. An exemplary design in SiGe BiCMOS technology is presented.
COVID-19 infection in pregnancy: a review of existing knowledge
Authors: Misra Swayam Swaroop , Ahirwar Ashok Kumar , Sakarde Apurva , Kaim Kirti , Ahirwar Pradeep , Jahid Mohd. , Sorte Smita R , Lokhande Suryabhan Lahanu , kaur Amar Preet , Kumawat Rajani 
Published: February 2022

Abstract
The world has been coping up with the grave pandemic of COVID-19 since its inception into the human race in December, 2019. By entering the host through the spike (S) glycoprotein, it paves way for its own survival and multiplication. Respiratory tract being the point of entry causes pulmonary compromise and leads to development of ARDS. Having non-specific clinical features that resemble flu makes the clinical diagnosis much more difficult. Pregnancy being an immunocompromised and a hypercoagulable state is prone to be a high-risk group for COVID-19. This study is an attempt to understand the maternal and fetal outcomes in COVID-19 and the vertical transmissibility of the virus. Evidence suggests that the contribution of COVID-19 is not very significant in maternal morbidity and mortality. However, due to some factors such as the immunological response in the mother, certain complications may arise in the neonate in the post-natal period. No vertical transmission of the virus has been reported yet. However, the management remains crucial as two lives are at stake. Some of the precautionary measures that can be implemented to prevent COVID-19 can be segregation of medical services from that of the general population in settings of outpatient care, inpatient care and labor room care. Also, triaging the patients into low risk, moderate risk and high risk can aid in faster delivery of health-care facilities to the pregnant and the newborn.
Low Temperature Carburizing of Stainless Steels and the Development of Carbon Expanded Austenite*
Authors: Werner K. V. , Che H. L. , Lei M. K. , Christiansen T. L. , Somers M. A. J. 
Published: February 2022

Abstract
Low-temperature carburizing dramatically enhances the inherently low wear resistance of austenitic stainless steels due to the formation of a carbon-supersaturated solid solution, i.e. expanded austenite. The formation of expanded austenite from low-temperature carburizing has been intensively investigated. However, the influence of chemical composition of the stainless steel on the carburizing response has not received the same interest. This contribution addresses the effect of the chemical composition on low-temperature carburizing in terms of carbon solubility, decomposition of expanded austenite upon exceeding the solubility limit and the elasto-plastic accommodation of the carbon-induced lattice expansion. The results demonstrate that the carbon solubility increases with an increasing Cr-equivalent and that higher Cr- and Ni-equivalents favor the formation of Cr-based M7C3 over Fe-based Hägg (M5C2) carbide.
Interrelation between Microstructure and Residual Stresses for Low-Pressure Carburizing of Steel AISI 5120 under Defined Process Parameter Variation
Authors: Zuern M. G. , Tapar O. B. , Ho P. , Epp J. , Gibmeier J. 
Published: February 2022

AbstractLow-pressure carburizing (LPC) is a recipe-controlled process for surface layer hardening. These recipes are mainly based on experience and contain the process parameters used to achieve the desired hardening result. The process parameters influence the chemical gradients which have set in the boundary layer, the local microstructure and the depth distribution of the process-induced residual stresses. Within the scope of this work, a systematic parameter study and advanced characterization was carried out to quantify the influence of these process parameters on the resulting material state. The varied parameters include the carburizing temperature, the hardening temperature, the quenching rate as well as the number of repetitions and durations of the carburizing cycles’ steps. The results obtained should help to extend the fundamental process understanding of the LPC process. The analyses showed that the retained austenite content and its depth profile change significantly for certain process parameter variations, reaching contents of up to 45 vol% in the near-surface region. The differences regarding the residual stress states of the case-hardened samples can first and foremost be related to the formation of varying depth distributions of the retained austenite.
Deformation and Microstructure of Titanium Chips and Workpiece
Authors: Siemers Carsten , Mukherji Debashis , Bäker Martin , Rösier Joachim 
Published: February 2022

Abstract
In order to improve the machinability of titanium alloys, a better understanding of the chip formation process is needed. Microstructur alanalysis of chips produced at high cutting speeds can lead to an estimate of temperatures and the deformation state in the chips if structural changes can be observed. Two-dimensional cross-sectional analyses are performed by means of optical microscopy (LM) and transmission electron microscopy (TEM). To study the deformation state of the finished workpiece, a scratch-grid method in combination with a scanning electron microscope (SEM) is used. The results of the different analyses for Ti 6A14V are presented in this paper and are compared with a finite element simulation of an orthogonal cutting process.
Grain Growth in the Nanocrystalline W–Cu and Cu–Pb Composite Powders Prepared by Mechanical Alloying
Authors: Moon In Hyung , Ryu Sung-Soo , Kim Soon-Wook , Won Dong Mook , Jang Won Suck 
Published: February 2022

Abstract
The thermal behavior of the nanocrystalline W–Cu and Cu–Pb powders was investigated in order to gain thermal stability information for further application and also to elucidate the grain growth kinetics in an immiscible alloy system. The nanocrystalline alloy powders were prepared by mechanical alloying (MA) and characterized. Thermal behavior of this nanocrystalline alloy was analysed by DSC, XRD, SEM, TEM and EXAFS. The time exponent n and the activation energy for grain growth were determined from the grain size data. The nanocrystalline W, Cu and Pb have revealed lower n values than the polycrystalline ones. The activation energy of the nanocrystalline W, Cu, and Pb grain growth in MAW–Cu and Cu–Pb powders is 186.5 ± 1.0, 55.6 ±10.5 and 42.0 ± 3.9 kJ/mol, respectively. The melting point suppression of Pb crystalline embedded in Cu matrix in MA Cu–Pb powders can be estimated. On the basis of the grain growth parameter obtained in this study and available data in the literature, the grain growth features and kinetics in the nonequilibrium state of the immiscible alloy system are discussed.
Internal Friction and Creep of Titanium Aluminides with Different Microstructure
Authors: Weller Manfred , Chatterjee Anita , Haneczok Grzegorz , Arzt Eduard , Appel Fritz , Clemens Helmut 
Published: February 2022

AbstractATi-46.5 Al-4 (Cr, Nb, Ta, B) alloy (at.%) with different microstructures (fine-grained primary annealed or coarsegrained fully lamellar) was examined both by mechanical-loss (internal-friction) and creep experiments. The mechanical-loss spectra (0.01– 10 Hz), ranging from 300 up to 1300 K, show two phenomena: (i) A loss peak at about 900 K (0.01 Hz) which occurs only in samples with a lamellar microstructure. The activation enthalpy, determined from the frequency shift, is 3.0 eV. The Debye-type peak is related to thermally activated reversible local movement of dislocation segments which are pinned at the lamellae interfaces and within gamma lamellae, (ii) A high-temperature damping background above 1000 K which is controlled by an activation enthalpy of 3.8 to 3.9 eV. This value agrees well with the activation enthalpy determined by creep tests and is in the range of values reported for self-diffusion of Al. These results indicate that both properties (high-temperature background and creep) are controlled by volume diffusion-assisted climb of dislocations.
Niobium bulk and grain boundary diffusion in alpha-iron
Authors: Herzig Chr. , Geise J. , Divinski S.V. 
Published: February 2022

Abstract
Bulk and grain boundary (GB) diffusion of Nb in α-Fe were studied in the temperature interval from about 700 to 1100 K by the radiotracer method combined with serial sectioning. A non-Arrhenius temperature dependence of Nb bulk diffusion was established below the Curie temperature T
c. This observation was discussed in relation to the well-known magnetically-induced diffusion anomaly in α-Fe and to the contribution of dislocation diffusion. In contrast, a practically linear Arrhenius temperature dependence was found for Nb GB diffusion. At Tc, bulk and GB diffusion of Nb are about one order of magnitude faster than the corresponding self-diffusivities of α-Fe. The effect of matrix purity on Nb GB diffusion in α-Fe was studied.
Modelling the continuous cooling transformation diagram of engineering steels using neural networks
Authors: van der Wolk Pieter J. , Wang Jiajun , Sietsma Jilt , van der Zwaag Sybrand 
Published: February 2022

Abstract
A neural network model for the calculation of the phase regions of the continuous cooling transformation (CCT) diagram of engineering steels has been developed. The model is based on experimental CCT diagrams of 459 low-alloy steels, and calculates the CCT diagram as a function of composition and austenitisation temperature. In considering the composition, 9 alloying elements are taken into account. The model reproduces the original diagrams rather accurately, with deviations that are not larger than the average experimental inaccuracy of the experimental diagrams. Therefore, it can be considered an adequate alternative to the experimental determination of the CCT diagram of a certain steel within the composition range used. The effects of alloying elements can be quantified, either individually or in combination, with the model. Nonlinear composition dependencies are observed.
The effect of grain size on the mechanical properties of nanonickel examined by nanoindentation
Authors: Yang Bo , Vehoff Horst 
Published: February 2022

Abstract
Nanocrystalline nickel produced by pulsed electrolysis was heat-treated to produce grain sizes from nanoscale to microscale. A special polish allowed to image the specimen with an atomic force microscope (AFM) down to a grain size of 30 nm. Micro- and instrumented nanohardness of these specimens were examined. A NI-AFM (Nanoindenting AFM) was used to measure the interaction between grain boundaries and dislocations. Nanoindentation was performed always in the center of the grains. When the size of the indent was kept constant (constant strain) it could be shown that the hardness scales with the dislocation density within the grains. However, when the size of the indent approached the grain size, the plastic zone spread over several grains and a decrease in hardness was observed. In addition, with deceasing grain size, grain boundary sliding was observed even at room temperature.
Deformation behaviour and microscopic investigations of cyclically loaded railway wheels and tyres
Authors: Walther Frank , Eifler Dietmar , Mosler Ulrike , Martin Ulrich 
Published: February 2022

Abstract
Railway wheel and tyre steels were investigated by specimens from defined volume sections representing the local microstructure of original components. As a consequence of the industrial heat treatment and the size of the components, microstructural gradients exist in the wheel rim and tyre crosssection. The ferrite fraction of the ferritic – pearlitic microstructure and the cementite lamellae spacing vary depending on the distance to the running surface (tread). Stress-controlled load increase and single-step push– pull tests were carried out at ambient temperature with servohydraulic testing systems to study fatigue phenomena with special consideration of microstructural details. Mechanical stress– strain hysteresis, thermometrical, and electrical measurements were used for a comprehensive characterization and evaluation of the cyclic deformation behaviour. The measured physical quantities show a strong interrelation with the underlying fatigue process. Light, scanning, and transmission electron microscopy (TEM), together with digital image processing, allow to interpret the measured data on the basis of microstructural details. In defined fatigue states, TEM investigations were performed to correlate the loading conditions with the appearing dislocation structures.
Nitriding behaviour of the intermetallic alloy FeAl
Authors: Spies Heinz-Joachim , Biermann Horst , Fischer Anke 
Published: February 2022

Abstract
An iron-based intermetallic FeAl alloy was gas nitrided under well-defined conditions, and the influences of the process parameters, i. e., time, temperature, and nitriding potential on the layer formation, were investigated. Microstructural, morphological, and chemical characterization of the nitride layer was performed by means of glow discharge optical spectroscopy, electron probe microanalysis, scanning electron microscopy, X-ray diffraction, internal-stress measurement, hardness– depth profiles, and indentation fracture mechanics. Pin-on-disk tests were carried out to investigate the load-bearing capacity and wear resistance of the nitride layers. The formation of hexagonal AlN during the nitriding treatment leads to an increase in hardness of about 920 – 980 HV 0.025 and to a significant improvement of the wear resistance. Additional annealing tests proved the thermal stability of the nitride layer up to 950 °C.
On the Orowan stress in intermetallic ODS alloys and its superposition with grain size and solid solution hardening
Authors: Saage Holger , Heilmaier Martin , Eckert Jürgen 
Published: February 2022

Abstract
The intermetallic trialuminide Al67Ti25Cr8 was strengthened by nano-scaled dispersions of up to 3 vol.% yttrium and aluminum oxide via mechanical milling. Subsequent powder consolidation, heat treatment, and thermo-mechani-cal treatment yielded grain growth to an increasing degree, resulting in grain sizes ranging from sub-μm level to about 0.5 mm. Consequently, the room-temperature yield strength σ
0 as determined by constant compression rate tests, increases due to three different hardening contributions, namely dispersion strengthening σ
OR due to Orowan bypassing, fine-grain strengthening σ
HP due to Hall-Petch relation, and, finally, as virtually always present, some solid-solution strengthening σ
s. The analysis of the particle parameters was done using TEM as well as focused ion beam (FIB) imaging. The latter provides the opportunity to directly determine the mean radius r

s
of planar intersections with spherical particles and their nearest-neighbour spacing L since it displays a plane section through the 3-dimensional arrangement of dispersoids. The analysis of the strengthening contributions indicates that a Pythagorean superposition permits an appropriate modeling of the measured yield strength σ
0.
Effects of particle reinforcement on creep behaviour of AlSi1MgCu
Authors: Requena Guillermo Carlos , Degischer Hans Peter 
Published: February 2022

Abstract
The creep resistance of an unreinforced and a particle-reinforced AlSi1MgCu alloy (AA6061) produced by liquid metallurgy was studied by means of conventional tensile creep tests at 300 °C. Dislocation-creep mechanism is attributed to both materials in the range of 15 – 50 MPa. The particlereinforced metal (PRM) exhibits a higher creep rate than the matrix alloy because of the particles acting as dislocation sources and the increase of the apparent diffusion coefficient due to a higher defect density. The apparently smaller creep exponent for the matrix is explained by the overaging of Mg2Si precipitates during longterm tests. Void formation leads to strain localisation in the unreinforced alloy, which is dispersed by the particles reducing the damage rate in the PRM. Subsequently, the time to rupture of the PRM surpasses that of the unreinforced matrix at creep stresses smaller than 10 –3 G (20 MPa).
Focussing and defocussing effects at radio frequency glow discharge optical emission spectroscopy analyses of thin films with partly nonconductive components
Authors: Hoffmann Volker , Hecker Michael , Hübner René 
Published: February 2022

Abstract
The application of radio frequency glow discharge optical emission spectroscopy for the investigation of the stability of different diffusion barriers for microelectronic applications against thermal diffusion of Cu is presented. Difficulties in the interpretation of the glow discharge results are overcome by performing an additional special experiment, where conductive and nonconductive parts are sputtered intentionally at the same time.
As a consequence of the investigations, care must be taken, if glow discharge spectrometry is applied to samples with conductive and nonconductive components.
Structure, properties and applications of diamond-like carbon coatings prepared by reactive magnetron sputtering
Authors: Bewilogua Klaus , Brand Jochen , Thomsen Helge , Weber Martin , Wittorf Ralf 
Published: February 2022

AbstractMetal containing and metal free amorphous diamond-like carbon films were prepared by reactive magnetron sputter deposition using targets from transition metals or graphite and acetylene as reactive gas. Both types of coating materials are well known for their low friction coefficients. However, metal containing films exhibit clearly lower wear resistances and lower hardness values than metal free films. To study the differences between both materials, tungsten containing and metal free coatings were compared. The deposition experiments were carried out in an industrial scale d.c. magnetron sputter machine. Transmission electron microscopy, secondary ion mass spectroscopy, and Raman spectroscopy as well as hardness measurements and wear tests were performed to characterize and to compare composition, structure, mechanical, and tribological properties of both coating materials.
„Zu verbessern hielt ich für keine gute Idee in dieser Situation“ – zur mündlichen Korrekturkompetenz als Teil der universitären Ausbildung von DaF-Lehrkräften
Authors: Hertzel Angelique , Zeyer Tamara 
Published: February 2022

Zusammenfassung
Was genau als Fehler identifiziert wird und wie eine angemessene Reaktion darauf in fremdsprachlichen Erwerbskontexten aussehen sollte, gilt als eine der zentralen Herausforderungen für unterrichtliche Interaktionen. Im Beitrag wird eine qualitative Studie zum Korrekturverhalten von DaF-Masterstudierenden im Gießener Elektronischen Praktikum (GEP) der Universität Gießen vorgestellt.
Orientierungen angehender Lehrpersonen im Bereich Sprachbildung und Deutsch als Zweitsprache: Rekonstruktionen von Praxiserfahrungen
Authors: Skintey Lesya 
Published: February 2022

Zusammenfassung
Die Professionalisierung angehender Lehrkräfte für Fragen rund um sprachliche Bildung, Deutsch als Zweitsprache und Mehrsprachigkeit ist in den letzten Jahren verstärkt in den Blick der Praxis und Forschung der Lehrkräfteausbildung gerückt. Während in der bisherigen Forschung vor allem Wissen und Einstellungen als Elemente der DaZ-Kompetenz bei Studierenden untersucht wurden, wird in diesem Beitrag der Frage nachgegangen, wie angehende Lehrkräfte mit sprachlich-kultureller Heterogenität in der Praxis umgehen. Im Fokus stehen dabei die Ergebnisse einer Studie zu Orientierungen von Lehramtsstudierenden, die an einer Zusatzqualifizierung im Bereich Sprachbildung und Deutsch als Fremd- und Zweitsprache teilnehmen. Anhand von ausgewählten Praktikumsberichten und transkribierten Reflexionsgesprächen wurden mittels der dokumentarischen Methode handlungsleitende Orientierungen der Studierenden bei der Unterrichtsplanung, -durchführung und -reflexion rekonstruiert. Die Auswertungen zeigen, dass sich die Zertifikatsteilnehmenden bei der Praxisgestaltung neben den fachwissenschaftlichen und fachdidaktischen Wissensbeständen auch an strukturellen Rahmenbedingungen, Lehrmaterialien, Perspektiven der anderen Akteur*innen und alltäglichen Wissensbeständen orientieren. Diese Erkenntnisse werden im Hinblick auf deren Relevanz für die weitere Forschung und Lehrkräfteprofessionalisierung diskutiert.
Throughput analysis of dual hop hybrid RF-VLC system with wireless energy harvesting
Authors: Vats Anshul , Aggarwal Mona , Ahuja Swaran 
Published: February 2022

Abstract
In this paper, we study a dual hop hybrid radio frequency-visible light communication (RF-VLC) system with wireless energy harvesting technique. In the proposed model the RF channel and the VLC channel are modelled by generalized-K distribution and lambertian emission model, respectively. A decode and forward relay is used as an intermediate node where power splitting relaying (PSR) protocol is employed to harvest energy from the received RF information signal. The source transmits the information signal towards the relay via RF channel. The relay then decodes the received signal and convert it into corresponding light signal. Simultaneously the energy harvesting circuit at relay harvests the energy from the received RF signal. The relay utilizes the harvested energy to aid the transmission of the light signal towards the user situated inside the building’s room at the destination. Further, the statistics of the instantaneous SNR of the hybrid RF-VLC system at the destination are derived by employing the PSR protocol to obtain an accurate closed form analytical expression for the system’s end-to-end ergodic capacity and achievable throughput in terms of Meijer’s G function. Further, with the help of numerical simulations, we analysed the end-to-end ergodic throughput performance of the hybrid system under the influence of varying channel parameters such as signal to noise ratio, power splitting factor, shadowing parameters, distance between source & relay and source transmitted power.