bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluations of the CCFL and critical flow models in TRACE for PWR LBLOCA analysis
Authors: Yang J.-H. , Lin H.-T. , Wang J.-R. , Shih C. 
Published: December 2013

Abstract
This study aims to develop the Maanshan Pressurized Water Reactor (PWR) analysis model by using the TRACE (TRAC/RELAP Advanced Computational Engine) code. By analyzing the Large Break Loss of Coolant Accident (LBLOCA) sequence, the results are compared with the Maanshan Final Safety Analysis Report (FSAR) data. The critical flow and Counter Current Flow Limitation (CCFL) play an important role in the overall performance of TRACE LBLOCA prediction. Therefore, the sensitivity study on the discharge coefficients of critical flow model and CCFL modeling among different regions are also discussed. The current conclusions show that modeling CCFL in downcomer has more significant impact on the peak cladding temperature than modeling CCFL in hot-legs does. No CCFL phenomena occurred in the pressurizer surge line. The best value for the multipliers of critical flow model would be 0.5 and the TRACE could consistently predict the break flow rate in the LBLOCA analysis as shown in FSAR.
High-resolution two-phase flow measurement techniques for the generation of experimental data for CFD code qualification
Authors: Hampel U. , Krepper E. , Lucas D. , Beyer M. , Szalinski L. , Banowski M. , Barthel F. , Hoppe D. , Bieberle A. , Barth T. 
Published: December 2013

Abstract
Computational fluid dynamics simulations for two-phase flows are important in different fields of engineering and science. Since two-phase flows are inherently complex, also CFD modeling development requires special attention. The validation of model implementation and the derivation of physics based models for momentum, heat, and mass transfer in two-phase flow require experiments with generation of high-resolution measurement data. This, however, is a great challenge, since most standard flow measurement tools used in single phase flow situations, are not suited for multiphase flows. In this article we report on advanced imaging and measuring methods for two-phase flow experiments, which have been extensively used in the recent past to conduct experiments for two-phase flows at the Helmholtz-Zentrum Dresden-Rossendorf. In particular the application of wire-mesh sensors, ultrafast X-ray tomography, gamma ray tomography and positron emission tomography will be introduced and discussed.
Case studies for evaluating conditional probabilities of external explosions
Authors: Hauschild J. , Andernacht M. , Berg H. P. 
Published: December 2013

Abstract
In recent years international experience has shown that external hazards can be safety significant contributors to the risk for nuclear power plants because such hazards have the potential to reduce simultaneously the level of redundancy by damaging redundant systems. Therefore, effective protections against external hazards have to be accurately assessed applying deterministic, probabilistic or combined methodologies. With respect to the external hazard “explosion” – two different types of risky situations for the plant under consideration have to be investigated: the explosive material is available as a stationary source in the neighbourhood of the plant or the explosive material is mobile (i. e. by ships, rails or trucks). In the latter case, the situation changes with the varying distances. Moreover, the transport way could be a straight line or a bent which also has to be addressed in the calculations. Methods which can be applied to evaluate the probability of occurrence of an external explosion event are, e. g., fault tree analyses, event tree analyses and Monte Carlo simulations. Two case studies applying Monte Carlo simulations for assessing the probability of occurrence of external explosion events, given an accident with creation of an explosive gas cloud, are presented.
Modeling of DECL accident in the reactor containment by the CONTAIN 2.0 code
Authors: Abbasi M. , Rahgoshay M. 
Published: December 2013

Abstract
In this paper, a specific type of the Loss of Coolant Accident (LOCA), the DECL (Double Ended Cold Leg) break, that means totally guillotine type of break in the cold leg pipe, has been modeled. The accident is simulated with the CONTAIN 2.0 code. In the event of a LOCA accident, coolant mass and energy are released to the containment through the break. This causes an increase of pressure and temperature in the containment. The modeling is performed in the VVER-1000 reactor containment. The analysis includes average pressure in the containment and temperature distribution in sample cells in the long-time. The results are compared with the existing reports on studies that used the ANGAR code. Results show that the CONTAIN 2.0 code is an adaptable tool for the analysis of nuclear events such as DECL accident.
Seasonally gross alpha and beta activity concentration in surface water and sediments in Sır Dam Pond
Authors: Çam H. , Doğru M. , Küçükönder A. , Karatepe S. 
Published: December 2013

Abstract
Seasonally gross alpha–beta activities were measured in surface water and sediments in Sır Dam Pond (Kahramanmaras, Turkey). Six sampling sites were pre-defined in different locations of the Sır Dam Pond. Preliminary studies of gross-α and gross-β activities in the surface water and deep sediments were determined. The results obtained from the determination of the activity indicate that gross-α and gross-β activities were ranging from 0,007 ± 0,005 to 0,077 ± 0,006 Bq/l and from 0,028 ± 0,006 to 0,189 ± 0,009 Bq/l for the surface water and from 0,001 ± 0.001 to 0,229 ± 0,032 Bq/g and from 0,144 ± 0,026 to 0,419 ± 0,033 Bq/g for deep sediment, respectively.
Evolution of the mixed-mode character of solid-state phase transformations in metals involving solute partitioning
Authors: Sietsma Jilt , Mecozzi M. Giuseppina , van Bohemen Stefan M. C. , van der Zwaag Sybrand 
Published: December 2013

Abstract
Partitioning phase transformations in the solid state are principally subjected to two processes that take place: the redistribution, through long-range diffusion, of the partitioning element, and the lattice transformation taking place at the interface. Consequently, the usual approximation to consider one of these two processes as controlling the rate of the phase transformation is of limited accuracy. For a more accurate description, the so-called mixed-mode character of partitioning phase transformations is to be taken into account. In the present study, it is shown that the mixed-mode character can be quantified and that it has a significant effect on the kinetics. By means of examples involving either substitutional (Mo in Ti) or interstitial (C in Fe) partitioning elements, it is shown that a gradual change of the character of the transformation occurs during the phase transformation, shifting from initially interface-controlled (which implies the largest interface velocity) towards more diffusion-controlled.
An indirect approach to measure glass transition temperature in metallic glasses
Authors: Jin H. J. , Lu K. 
Published: December 2013

Abstract
Glass transition behavior of metallic glasses under some extraordinary conditions (such as under high pressures) remains unexplored. Conventional measurements of glass transition temperature, Tg, are very difficult to perform under these extraordinary circumstances. In the present paper, we introduce an indirect approach to characterize glass transition, using enthalpy recovery experiments. With annealing deeply relaxed glassy samples and subsequent DSC measurements, a variation of enthalpy change upon heating with annealing temperature can be obtained. The variation of enthalpy change, a signature of glass transition, was found to correlate well with the directly measured DSC curves for the glass transition. This unique method was successfully applied in determining Tg of several metallic glasses under hydrostatic high pressures and compression stresses.
Experimental investigation and thermodynamic modelling of the Mg–Al-rich region of the Mg–Al–Sr System
Authors: Cao Hongbo , Zhu Jun , Zhang Chuan , Wu Kaisheng , Saddock Nicholas D. , Jones J. Wayne , Pollock Tresa M. , Schmid-Fetzer Rainer , Chang Y. Austin 
Published: December 2013

Abstract
A thermodynamic description of the Mg–Al–Sr ternary in the Mg–Al-rich region was developed based on the microstructures, the crystal structures and compositions of the phases in three samples in the as-cast and 673K annealed states. The gross compositions of the three alloys were identified for investigation based on a calculated isotherm using the description obtained from those of the constituent binaries via extrapolation. The calculated liquidus projection using the developed description was found to be consistent with the primary phases of solidification obtained from two additional alloys in the as-cast state. In addition, the model-calculated isotherm and liquidus projection are able to rationalize results reported in a recent publication for this ternary. This paper demonstrates the power of using a preliminary calculated phase diagram for selecting key alloys for experimentation, on basis of which a reliable thermodynamic description can be developed.
Knudsen effusion mass spectrometric studies of the Al–Ni system: Thermodynamic properties over {AlNi + Al3Ni2} and {Al3Ni2 + Al3Ni}
Authors: Narasimhan Tiruppatur Subramaniam Lakshmi , Kath Dieter , Wessel Egbert , Markus Torsten , Hilpert Klaus 
Published: December 2013

Abstract
Vaporisation studies on Al–Ni alloys with x(Ni)=0.43, 0.42, 0.35, and 0.32 were carried out by Knudsen effusion mass spectrometry. Partial pressure-temperature relations of Al(g) over the two phase regions {AlNi + Al3Ni2} and {Al3Ni2 + Al3Ni} were determined in the temperature ranges 1104–1278K and 1021–1122K, respectively. The corresponding equations are log(p(Al)/Pa) = −(20039±84)/T(K) + (13.4640.070) for {AlNi + Al3Ni2} and log(p(Al)/Pa) = −(16836 ± 235)/T(K) + (11.3450±.219) for {Al3Ni2 + Al3Ni}. The vaporisation reactions, Al3Ni2.025(s) = 2.6436AlNi0.766(s) + 0.3564Al(g) and Al3Ni(s) = 0.572Al3Ni1.747(s) + 1.284Al(g) were evaluated and subsequently the enthalpy and Gibbs energy of formation of Al3Ni1.747(s) were derived.
Comparing the thermodynamic behaviour of Al(l) + ZrO2(4%Y2O3) and Al(l) + Al2O3
Authors: Copland Evan 
Published: December 2013

AbstractIn an effort to better determine the thermodynamic properties of Al(g) and Al2O(g) the vapour in equilibrium with Al(l) + 4at.% yttria-stabilized zirconia (YSZ) was compared to the vapour in equilibrium with Al(l) + Al2O3(s) over the temperature range 1197–1509K. This comparison was made directly by Knudsen effusion-cell mass spectrometry with an instrument configured for a multiple effusion-cell vapour source (multi-cell KEMS). Second-law enthalpies of vaporization of Al(g) and Al2O(g) together with activity measurements show that Al(l) + YSZ is thermodynamically equivalent to Al(l) + Al2O3(s), indicating that Al(l) remained pure and Al2O3(s) was present in the YSZ-cell. Subsequent observation of the Al(l)/YSZ and vapour/YSZ interfaces revealed a thin Al2O3-layer had formed, separating the YSZ-cell from Al(l) and Al(g) + Al2O(g), effectively transforming it into an Al2O3effusion-cell. This behaviour agreed with observations made for -NiAl(Pt) alloys measured in YSZ effusion-cell.
The deformation behaviour of electrodeposited nanocrystalline Ni in an atomic force microscope with a newly developed in situ bending machine
Authors: Yang B. , Vehoff H. , Hempelmann R. 
Published: December 2013

Abstract
Four-point-bending and strain-controlled fatigue experiments were performed on electrodeposited nanocrystalline nickel specimens at room temperature. For the first time, the deformation behaviour of bulk nanonickel specimens was studied in an atomic force microscope with a newly developed in situ bending machine. Results show that grain boundary sliding plays an important role during deformation, and the fatigue crack propagates along grain boundaries.
Experimental and thermodynamic evaluation of the Co–Cr–C system
Authors: Markström Andreas , Norgren Susanne , Frisk Karin , Jansson Bo , Sterneland Thérèse 
Published: December 2013

AbstractNew experimental results on the liquid+graphite+M7C3equilibrium are presented. The solubility of Co in the M7C3carbide has been measured at 1523 and 1723K. These measurements together with recently published measurements on the fcc+graphite+M7C3equilibrium show that the solubility of Co in the M7C3is much higher than predicted from thermodynamic calculations. A new thermodynamic description of the Co–Cr–C system is presented which accurately describes the solubility of Co in the M7C3carbide in the temperature range 1373–1723K.
The influence of orientation and aluminium content on the deformation mechanisms of Hadfield steel single crystals
Authors: Astafurova Elena G. , Kireeva Irina V. , Chumlyakov Yuriy I. , Maier Hans J. , Sehitoglu Huseyin 
Published: December 2013

Abstract
The low stacking fault energy and high carbon content in Hadfield steel make twinning the basic deformation mechanism from the onset of plastic deformation in [1¯11] and [011] oriented single crystals in tension at T = 77 – 300 K. Alloying with aluminium (2.7 Al in wt.%) results in an increase of stacking fault energy from 0.03 J · m2 to 0.05 J · m−2 and moves twinning to higher degrees of deformation (∊pl > 15 %). In aluminium-free [1¯23] crystals twinning starts after 20 % strain. For [1¯23], [001] orientations, aluminium additions change the dislocation arrangement from a uniform distribution to a planar dislocation arrangment and also suppress twinning. Intersections of dislocation pile-ups were found to be the governing factor for hardening in the aluminium-alloyed [001] crystals.
Fracture behavior of overmatched ductile iron weldment
Authors: Cetinel Hakan 
Published: December 2013

Abstract
The fracture behavior of welded ductile iron is discussed by means of experimental and theoretical studies. Ferritic nodular cast irons were joined by cold arc welding in order to obtain over-matched weldment in which the yield strength of the weld metal is higher than that of the base metal. As a result of the welding process, various regions with different mechanical properties formed in the welded specimens.
In the experimental part of the study, the mechanical properties of the different regions in the welded specimens were identified and J-Integral toughness values were determined by fracture toughness tests for different crack locations including the base metal, the heat affected zone and the weld metal.
In the numerical part of the study, finite element analyses were conducted by fixing 3-D models precracked at different locations for different crack lengths. In these models, after stress – strain analysis, stress triaxiality and plastic deformation characteristics around the crack tip were determined for each crack location and different crack sizes. It was found that stress triaxiality values increase with growing crack length. Different regions with different strength levels in the weldment affect the extension of plastic deformation in the models. Hindrance to the extension of plastic deformation at the heat affected zone and diffusion line causes an extra increase in stress triaxiality at the crack tip.
Model of a superlattice indentation
Authors: Kravchuk A. , Rymuza Z. 
Published: December 2013

Abstract
This paper deals with the problem of penetration of a conical indenter into a multilayer rigid – perfectly-plastic body. The penetration of the indenter is studied on the basis of the Haar and von Karman hypothesis. The analytical distribution of the contact stress is obtained. A relationship between Meyer hardness and yield stresses of the layers is established.
Effect of Ho additions on the microstructure and mechanical properties of Nb-22Ti-16Si-7Cr-3Al-3Ta-2Hf alloys
Authors: Tian Y. X. , Guo J. T. , Liang Y. C. , Wu C. L. , Zhou L. Z. , Ye H. Q. 
Published: December 2013

Abstract
The effect of Ho additions on the microstructure and compressive properties of the alloy Nb-22Ti-16Si-7Cr-3Al-3Ta-2Hf (at.%) was investigated by using scanning electron microscopy, X-ray diffraction, transmission electron microscopy and by performing compression tests. The results show that Ho additions cause remarkable microstructural refinement. The addition of 0.1 at.% Ho to the alloy increases its strength and ductility. When the amount of Ho is increased to 0.2 at.%, the strength and ductility decreases. Ho addition inhibits the formation of the (Ti, Nb)5Si3 phase and the amount of the (Ti, Nb)5Si3 phase decreases, even disappears, with increasing Ho content. In addition, the fracture surfaces of Ho-free alloys deformed at room temperature in compression tests exhibit cleavage for both the (Nb, Ti) solid solution and the (Nb, Ti)5Si3 intermetallic compound, while limited local plastic strain of the (Nb, Ti) solid solution is observed in Ho-doped alloys. The effect and mechanism of strengthening and plastic deformation of Ho additions to the alloy was discussed in view of the microstructure.
Study of interfacial reactions between Sn–Ag–Cu alloys and Au substrate
Authors: Jao Chien-Chung , Yen Yee-Wen , Zhang Shu-Hao , Lin Chung-Yung , Lee Chiapyng 
Published: December 2013

Abstract
Interfacial reactions between Sn – Ag – Cu lead-free solders and Au were investigated by the use of SAC/Au solid/solid reaction couples which were annealed at 150, 180 and 200 °C for various reaction times. Five intermetallic compounds, AuSn, AuSn2, AuSn4, (Au, Cu)Sn, and (Cu, Au)5Sn6, were formed at a higher temperature and lower Cu content. As the reaction temperature was dropped and Cu content was increased, only three intermetallic layers, AuSn, (Au, Cu)Sn, and (Cu, Au)5Sn6, could be observed. Meanwhile, when the Cu content in SAC alloys increased, the thickness of total reaction layers decreased, but that of (Au, Cu)Sn/(Cu, Au)6Sn5 layers increased. It likely resulted from (Au, Cu)Sn/(Cu, Au)6Sn5 layers acting as a diffusion barrier to resist Sn diffusing to Au – Sn intermetallic compounds and decrease the growth rate of Au – Sn intermetallic compounds. The growth and formation of intermetallic compounds are sensitive to the reaction temperature and Cu content in the SAC/Au couple systems.
Bismuth activity measurements and thermodynamic re-optimization of the Ni–Bi System
Authors: Vassilev Gueorgui P. , Romanowska Jolanta , Wnuk Grzegorz 
Published: December 2013

Abstract
Bismuth thermodynamic activities in Ni – Bi liquid solutions have been measured by the modified isothermal isopiestic method at 1723, 1753 and 1773 K. These results are coupled with thermochemical and topological data from literature, in order to achieve reliable re-optimization of the Ni – Bi system by the CALPHAD method. The model of disordered substitutional solutions has been applied to the liquid phase and to the face-centered cubic solid solutions (Ni). The compound NiBi3 is stoichiometric and is modeled by a two-sublattice model corresponding to its formula. The nickel solubility in the solid bismuth is negligible, which is why the phase (Bi) is considered as consisting of bismuth only. The description Bi: Ni, Va has been used for the thermodynamic modeling of the nonstoichiometric NiBi phase.
Adaptierung einer Hochtemperatur-Belastungseinrichtung für die Raster-Elektronenmikroskopie mit Unterstützung von Finite-Elemente-Modellierung
Authors: Dimmler G. , Weidinger Th. , Cerjak H. 
Published: December 2013

Kurzfassung
Die Möglichkeit einer direkten Verfolgung zeitlich ablaufender werkstoffkundlicher Prozesse ohne Unterbrechung des Belastungskollektivs (“in-situ”-Untersuchungen) mit Hilfe einer Hochtemperatur-Belastungseinrichtung im REM stellt neue Perspektiven für das tiefere Verständnis von Werkstoffphänomenen dar. Im Rahmen dieser Arbeit wurde eine geeignete Probengeometrie hinsichtlich Temperatur- und Spannungsverteilung mit Unterstützung von Finite- Elemente- Modellierung erarbeitet. Das gewonnene Verständnis der unterschiedlichen Wechselwirkungen zwischen der Belastungseinrichtung und dem Rasterelektronenmikroskop ist dabei eine wichtige Basis für eine weitere Optimierung der Versuchsdurchführung. Derzeit können kinetische Prozesse an speziellen Proben bei Temperaturen bis 650°C und einer Zug-/Druckbelastung von theoretisch bis zu 10 000 N untersucht werden. Zusätzlich ist die Simulation eines beliebigen Spannungs- und Temperaturprofils durch die volldigitalisierte Mikroprozessorsteuerung gegeben. Mit der Belastungseinrichtung können Kurzzeit-Kriechversuche mit kontinuierlicher Dehnungsmessung und Strukturuntersuchung der Oberfläche bei konstanter und frei wählbarer Temperatur durchgeführt werden. Ein durchgeführter Kurzzeitkriechversuch soll dabei als Vorbereitung für zukünftige in-situ Schädigungsuntersuchungen an 9–12% Cr-Stähle dienen.
Elektronenmikroskopische Untersuchungen an mit FIB-Präparation hergestellten Grenzflächen von biologischen Materialien und Werkstoffen: erste Ergebnisse
Authors: Burkhardt C. , Nisch W. 
Published: December 2013

Kurzfassung
Für die Untersuchung der Ultrastruktur von biologischen Zellen und Geweben ist die Elektronenmikroskopie ein wichtiges Hilfsmittel. Damit mit dieser Methode auch die Grenzfläche von biologischen Systemen und Werkstoffoberflächen gezielt untersucht werden kann, wurden in der vorliegenden Arbeit klassische Methoden der biologischen Präparation, die kritische Punkt- Trocknung und das Einbetten von kontrastierten Zellen in einem Polymer mit der Focused-Ion-Beam-Technik (FIB) kombiniert. Die Arbeiten wurden in einem Zwei-Strahl-Gerät durchgeführt, so dass die FIB-Präparation eines Querschnitts bei hoher Auflösung im Rasterelektronenmikroskop beobachtet werden kann. Es wird gezeigt, dass es möglich ist, Zellen und die Kontaktstellen der Zellen zu einem Substrat auf einer Sub-Mikrometer-Skala zu präparieren und abzubilden.
Schadensfall Schäden an Kupferrohren einer Fußbodenheizung
Authors: Panzenböck M. 
Published: December 2013

Kurzfassung
Kupfer wird sehr gerne im Bauwesen aus Gründen der sehr guten Korrosionsbeständigkeit und Verarbeitbarkeit eingesetzt. Trotz der hervorragenden Eigenschaften kommt es immer wieder zum Versagen von Rohrleitungen mit erheblichen Folgeschäden. Im diesem Fall kam es zum Auftreten von Leckagen an einer Fußbodenheizung. Die Schädigung ist nicht auf eine Wechselwirkung des Wärmetransportmediums mit dem Rohrwerkstoff zurückzuführen. Die Untersuchungen lassen erkennen, dass die Einflüsse von außen kommen und der Werkstoffzustand dabei eine entscheidende Rolle spielt.
Effect of Sr Addition on the Microstructure of a Rapidly Solidified Al-12 wt.% Si Alloy
Authors: Wang Yan , Zhang Zhonghua , Zheng Shaohua , Wang Weimin , Bian Xiufang 
Published: December 2013

Abstract
The effect of Sr addition on the microstructure of a melt-spun Al-12% Si alloy has been investigated using X-ray diffraction and transmission electron microscopy. The Sr addition has no effect on the phase constitution but has a marked effect on the microstructure of the melt-spun alloy. The distribution, morphology and orientation of Si in the melt-spun alloy with the Sr addition are different from those in the alloy without Sr. Under rapid solidification conditions, cooling rates play a dominant role in the microstructure formation of the Al-12% Si alloy.
Surface Upheavals, Pseudo Martensite, and Martensite Ghosts
Authors: Hornbogen E. 
Published: December 2013

Abstract
A survey is made on the application of some metallographic methods for the analysis of martensitic reactions. In this context the following aspects are discussed:
Reverse reactions can be martensitic, to restore faultlessly the austenite, not fully reversible (defects accumulate), or diffusion controlled. In the last case austenite b must form by new nucleation and growth (crystallographic irreversibility). Then no surface upheavals form.