bluuebunny/crossref_metadata_2025_split huggingface dataset:
Betriebsfeste Bemessung von Steckverbindern in Steuergeräten∗
Authors: Kimpel Thomas , Jauernig Udo , Becker Rolf , Wagener Rainer , Kaufmann Heinz , Sonsino Cetin Morris 
Published: December 2013

Kurzfassung
Die Einpresstechnik ist eine kalte Kontaktiertechnologie und stellt eine Verbindung zwischen der Leiterplatte, die die Logikbauelemente trägt, und den äußeren Anschlüssen des Steuergeräts her. Die Hauptfunktion der Einpress verbindungen ist der Transport elektrischer Signale und Leistungen. Abhängig von der Konstruktion kann als weitere Funktion die mechanische Fixierung der Leiterplatte auftreten. Die Zuverlässigkeitsanforderung erfordert, dass die Funktionen über der Lebensdauer erhalten bleiben. Um die Funktionen unter zyklischer Belastung ermitteln und Veränderungen beobachten zu können, wurde ein Modellkörper für die Einpressverbindungen entwickelt. Weiterhin wurde ein geeigneter Prüfstand gebaut, mit dem die in der Fertigung und im Betrieb auftretenden Belastungen abgebildet wurden. Die Fehlerbilder der Einpressverbindungen und deren Schädigungsmechanismen, die durch zyklische Belastungen auftreten können, wurden am Modellkörper erarbeitet. Dabei war der Fokus auf die Kontaktzone gerichtet, die als Fügestelle zwischen Einpresspin und Leiterplattenhülse eine mögliche Schwachstelle darstellt. Es wurde gezeigt, dass der elektrische Übergangswiderstand der Kontaktzone durch vollflächige Reibkorrosion zu einem funktionalen Ausfall der Einpressverbindung führt. Eine Korrelation zwischen der mechanischen Festigkeit der Kontaktzone und dem Verhalten des Übergangswiderstands bei zyklischer Belastung wurde hergestellt. Dabei wurden die multiphysikalischen Eigenschaften der Fügestelle mit dem Ziel ausgenutzt, den Schädigungsmechanismus der vollflächigen Reibkorrosion über der Lebensdauer zu vermeiden. Eine geeignete Prüfmethode zur experimentellen Ermittlung der dreidimensionalen Belastbarkeit wurde entwickelt.
Betriebsfestigkeitsbewertung von Leichtbauklebeverbindungen–Herausforderungen bei Faserverbund- und Hybridbauteilen∗
Authors: Oppermann Helge , Metschkoll Matthias , Becker Ingo , Fröschl Jürgen 
Published: December 2013

Kurzfassung
Der zunehmende Anteil an Faserverbundbauteilen in Karosseriestrukturen macht den Einsatz neuartiger Fügeverfahren zwischen Stahl und Faserverbundwerkstoffen erforderlich. Auf Grund der lokalen hohen Auslastung sind für diese Leichtbaufügeverfahren qualifizierte Betriebsfestigkeitsnachweismethoden notwendig. Der vorliegende Beitrag stellt die aktuellen Ergebnisse eines laufenden Methodenprojektes für die Betriebsfestigkeitsbewertung von Leichtbauklebeverbindungen vor. Nach einer Schilderung des Standes der Technik werden anhand von Versuchsergebnissen die unterschiedlichen Einflüsse wie Belastungsart, Umgebungs-temperatur etc. auf die zyklischen und statischen Festigkeitseigenschaften aufgezeigt sowie die Haupteinflussgrößen identifiziert. In einem zweiten Schritt werden die Vor- und Nachteile unterschiedlicher Betriebsfestigkeitsbewertungsmethoden solcher Klebeverbindungen anhand der Versuchsergebnisse identifiziert. Im Ausblick werden geplante Versuche an bauteilnahen Prüfkörpern zur Modellvalidierung vorgestellt sowie die bislang gewonnenen Erkenntnisse zusammengefasst.
Utilization of Power Plant Bottom-Ash Particles as Stabilizer in Aluminum Foams
Authors: Asavavisithchai Seksak , Prapajaraswong Attanadol 
Published: December 2013

Abstract
Aluminum foams, produced via powder metallurgical (PM) process, normally require the addition of ceramic particles in compaction stage, in order to increase both foamability of precursors and mechanical properties of the final foam products. Bottom ash particles are a by-product waste obtained from thermoelectric power plants which are commonly found to be used in landfill facilities. The major chemical constituent, approximately between 30 wt.-% and 60 wt.-%, of bottom ash particles is SiO2, depending on chemical composition in coal, sintering condition and environment, and other process parameters. In this study, we explore the feasibility of utilizing bottom ash particles of thermoelectric power plant wastes as stabilizer in aluminum foams. A small amount of two-size bottom ash particles (mean size of 78 µm and 186 µm), between 1 wt.-% and 5 wt.-%, have been added to aluminum foams. Foam expansion, macro- and microstructures as well as mechanical properties, such as compressive strength and microhardness, were investigated. The results from the present study suggest that bottom ash particles can be used as a stabilizing material which can improve both cellular structure and mechanical properties of aluminum foams.
Charakterisierung der Verformungsmechanismen bei hoch Mn-legierten Stählen unter einachsiger Zugbeanspruchung∗
Authors: Labudde Thorsten , Ingendahl Tobias , Wildau Maria , Saeed-Akbari Alireza , Hoffmann Sascha , Bleck Wolfgang 
Published: December 2013

Kurzfassung
In hoch Mn-legierten Stählen treten in Abhängigkeit von der Stapelfehlerenergie (SFE) Verformungsmechanismen wie verformungsinduzierte Martensitbildung (TRIP), mechanische Zwillingsbildung (TWIP) und homogenes Versetzungsgleiten (SLIP) während der plastischen Umformung auf. Die SFE kann thermodynamisch berechnet und in sogenannten Mechanismenkarten grafisch dargestellt werden. Zur Beschreibung des Zusammenhangs zwischen Verfestigungsverhalten und Verformungsmechanismus im System Fe-Mn-C wurde zunächst die standardisierte Messtechnik im einachsigen Zugversuch mit zusätzlichen orts- und zeitauflösenden Verfahren kombiniert. Mittels Infrarot-Thermografie lässt sich das Auftreten von Dehnungsbändern infolge dynamischer Reckalterung detektieren. Der Einsatz lokaler Dehnungsanalyse auf der Probenoberfläche ermöglicht die quantitative Analyse der lokal erreichbaren Dehnung. In den sog. TORNADO-Diagrammen wird das Auftreten charakteristischer Muster in der Entwicklung der momentanen Dehnrate über der wahren Spannung zur Bestimmung der dominierenden Verformungsmechanismen genutzt. Die Oberflächentopografieänderung infolge Martensit- und Zwillingsbildung sowie prozessbedingter Einflüsse wie der Textur wurde mittels Konfokalmikroskopie untersucht.
Charakterisierung und Modellierung von Stahl-Klebverbindungen unter crashartiger Belastung∗
Authors: Böhme Wolfgang , Lienhard Jörg , Memhard Dieter 
Published: December 2013

Kurzfassung
Zur Charakterisierung und Modellierung des Verformungs- und Versagensverhaltens von Stahl-Klebverbindungen des Klebstoffs Betamate 1496V wurden Hochgeschwindigkeitsversuche mit Rohrzug-, Scherzug- und 45°-Schrägzug-Proben bei crashrelevanten Dehn-/Scherraten bis zu 104 s−1 durchgeführt. Die Verformung der Klebschichten bis Bruch wurde optisch mit Hochgeschwindigkeitsvideokameras erfasst und mit Grauwertkorrelationsanalyse ausgewertet. Die ermittelten Spannungs-Dehnungskurven zeigen mit zunehmender Dehnrate einen deutlichen Festigkeitsanstieg und eine Abnahme der Bruchdehnungen. Die Scherspannungskurven liegen mit steigender Scherrate ebenfalls deutlich höher, verlaufen aber zunehmend flacher, während die Scherbruchdehnungen nahezu unverändert bleiben. Dies ist auf adiabatische Temperaturerhöhung zurückzuführen. Mit einem hierfür am Fraunhofer IWM erstellten Materialmodell zur Beschreibung des dehnratenabhängigen Klebstoffverhaltens wurden für die Hochgeschwindigkeitsscherversuche Temperaturerhöhungen der Klebschicht in einer Größenordnung von 50 K berechnet. Die Simulation wurde mit den Ergebnissen der 45°-Schrägzugversuche validiert.
Estimating the Lifetime of Fuel Cells by the Methods of Fatigue-Strength Analysis under Variable Stress Amplitude
Authors: Bonitz Saskia , Masendorf Rainer , Esderts Alfons 
Published: December 2013

Abstract
Estimating the fatigue life of metallic components has become an essential requirement in the industry because of the need to use light-weight constructions in conformance with stringent safety-relevant standards. However, the application of such methods for predicting the lifetime of electrochemical devices such as fuel cells is a novel approach. In this case, pertinent events and parameters, such as normal operation, open-circuit voltage, as well as starting and stopping processes, were extracted from the data determined from the measured current and voltage-time curve. For this purpose the classic counting methods, level-distribution counting and frequency counting are applied. The result thus obtained is assessed with the use of a damage parameter which describes the voltage drop as a function of time or of the number of cycles counted. Finally, the calculative estimation of the lifetime is determined by linear damage accumulation.
Analysis of Deposited Salts in the Through-Flow Area of a 210 MW Steam Turbine
Authors: Staniša Branko , Ćurković Lidija , Schauperl Zdravko 
Published: December 2013

Abstract
During the exploitation of a steam turbine, mainly because of non-adequate purity of fresh steam, salts can be deposited on the components in the through-flow area. Deposited salts decrease the reliability and efficiency of the steam turbine, while thicker layers, i. e. higher quantities of deposited salts, could cause serious damage to the turbine. This paper gives a description of deposited salt layers in the through-flow area of a 210 MW steam turbine and presents the results of research and analysis. In order to determine the cause of salt deposition on turbine surfaces, a chemical analysis of deposited layers was carried out. This paper proposes measures to reduce the salt deposition as well as methods for the removal of deposited layers in the through-flow area of a steam turbine.
Reinforcement of Steel Tubes with Rings under Compression
Authors: Açıkel Hicran , Kaltakcı Mevlüt Yaşar , Sönmez Ali 
Published: December 2013

Abstract
The goal of this study is to reinforce the compression strut ties of space truss systems by increasing the load carrying capacities of them. Therefore, 28 steel bar ties each having 900 mm length and 60.3 mm diameter were reinforced in six different ways and subjected to an axial compression test in the Structure Laboratory of the Civil Engineering department, Faculty of Engineering and Architecture, Selçuk University, Konya, Turkey. The results obtained from tests were examined by making comparisons between the plotted graphics. The applied reinforcement has not increased the buckling load, but it has increased the energy absorption capacity of reinforced bars under yielding and maximum stresses. When the negative effect due to welding is eliminated, a further increase in the energy absorption capacity at the yielding and proportionality limits and an increase in the maximum load carrying capacity can be expected.
Preparation of Hydroxyapatite Coating by Using Citric Acid Sodium Citrate Buffer System in the Biomimetic Procedure
Authors: Aydin Ibrahim , Cetinel Hakan , Pasinli Ahmet , Yuksel Mithat 
Published: December 2013

AbstractThe present study has been aimed to investigate the preparation and analysis of calcium phosphate (CaP) based hydroxyapatite (HA, Ca10(PO4)6(OH)2) coatings formed on Ti6Al4V alloys in a new buffer environment. The coating process has been performed by means of biomimetic method. In the study, a synthetic body fluid (SBF), which is fully compatible with human blood plasma, has been prepared for the first time in the literature by using the citric acid – sodium citrate buffer system. Using this buffer system will not cause any toxic reactions in the human body. CaP coating of the Ti6Al4V surface has been performed in this new SBF. The surface roughness and thickness specifications of the coatings have been determined, their microstructures have been analyzed by using a scanning electron microscope (SEM), the elemental analysis (EDX) of the coating surfaces and the XRD analysis have been done. The results are presented and discussed.
Comparison of ABC, CPSO, DE and GA Algorithms in FRF Based Structural Damage Identification
Authors: Gökdağ Hakan 
Published: December 2013

Abstract
In this contribution, performances of well-known population based algorithms, the artificial bee colony (ABC), contemporary particle swarm optimization (CPSO), genetic algorithm (GA), and differential evolution (DE) are compared in a basic model for damage identification (DI). DI is modeled as an inverse problem with the objective function based on the difference of the frequency response functions (FRF) computed by the finite element model of the structure and the reference data measured from damaged structure. Damage parameters are determined solving the problem with the aforementioned algorithms. It was observed that DE is the best one of a given number of function evaluations and gives the most accurate results in spite of noise interference to the reference data. According to the relevant literature, this is the first study including a comparison of these algorithms in an FRF based DI study.
Influence of Depth Alignment of E-Glass Fiber Reinforcements on Dental Base Polymer Flexural Strength
Authors: Vojvodić Denis , Kozak Dražan , Sertić Josip , Mehulić Ketij , Celebic Asja , Komar Dragutin 
Published: December 2013

Abstract
Fractures of denture base polymer material are one of the most frequent reasons for repair of removable dentures. The aim of this study was to determine the influence of depth alignment of glass fiber reinforcements onto denture base polymer flexural obtained with the “short beam” testing method. The study showed higher values of flexural strength when reinforcements were placed 1mm from specimen surface (130,63 to 158,55MPa) compared to 0,5mm distance from specimen surface (117,83 to 153,68MPa). Specimens tested after polymerization had higher flexural strength values than specimens tested after storage in water, while thermocycled specimens unexpectedly revealed the highest values. It could be concluded that fiber reinforcements should be positioned more than 0,5mm (up to 1mm) from the base surface of dental prostheses since lesser distance would diminish the reinforcing effect.
Sensitivity analysis of the Peach Bottom Turbine Trip 2 experiment
Authors: Bousbia-Salah A. , D'Auria F. , Bambara M. 
Published: December 2013

Abstract
The recent availability of powerful computer and computational techniques has enlarged the possibilities to perform best estimate simulations of complex scenarios in nuclear power plants. Nowadays, the coupled codes method, which consists in incorporating three-dimensional (3D) neutron modeling of the reactor core into system codes, is extensively used. It is particularly suited for simulating transients that involve core spatial asymmetric phenomena and strong feedback effects between core neutronics and reactor loop thermal-hydraulics. Within this framework the Peach Bottom BWR 2 Turbine Trip test was selected since it involves a rapid pressure induced positive reactivity addition into the core. It is also characterized by a self-limiting power course due to compensated inherent reactivity mechanisms. To perform a numerical simulation of the turbine trip a reference case was run for the coupled thermal-hydraulic system code RELAP5/mod3.3 and 3D neutron kinetic PARCS/2.3 code. The overall data comparison shows good agreements between the calculations and most of the significant global aspects observed experimentally. However, the test is very sensitive to the feedback modeling and requires a tightly accurate simulation of the thermal-hydraulic and the cross sections parameters. For this purpose, sensitivity studies have been carried out in order to identify the most influential parameters that govern the transient behavior. The considered cases showed that the self-limiting power amplitude as predicted by the coupled code calculation is mainly due to delayed feedback mechanisms whereas the experimental data shows that the power quenching before the Scram is governed by prompt feedback effects.
A new data-condensation method based on multidimensional minimisation
Authors: Lassmann K. , van de Laar J. 
Published: December 2013

Abstract
During irradiation in the Halden Reactor data such as linear rating, coolant temperature, or reactor state are routinely stored every 15 minutes, in the case of special events even at shorter time intervals. Because of the long irradiation times of up to several years, a huge amount of data is produced which is considered to be too much for direct input into fuel performance codes. In order to reduce the amount of data, various data-condensation procedures have been developed, which are briefly discussed. An innovative data-condensation method based on multidimensional minimisation is presented. The condensation factor obtained so far for Halden irradiations is 25–40, which is sufficient for a modern fuel rod performance code like TRANSURANUS. This new condensation method avoids all loss of experimental data and doubtful averaging of temperatures associated with other more drastic condensation methods. Up to now, the so-called reactor state variable, which defines the reactor operation (e. g. constant, decreasing or increasing power), has not been used. The introduction of this variable should further improve this new condensation method.
Improved Dancoff factors for cluster fuel bundles by the WIMSD code
Authors: Leite S. Q. Bogado , Zabadal J. R. S. , de Vilhena M. T. 
Published: December 2013

Abstract
The recently developed tracking routine PIJM, for computing improved two-dimensional first-flight collision matrices for the WIMSD code, has been modified to evaluate black Dancoff factors for cluster fuel bundles in unit cells with cylindrical outer boundaries. The routine, similar to the original PIJ but employing an efficient in-plane integration scheme of the Bickley functions appearing in those expressions, is first compared with the accurate Carlvik method in the calculation of Dancoff factors for regular lattices, both with and without a gap surrounding the fuel rods. Dancoff factors for the more general cases of CANDU37 and CANFLEX fuel bundles are next obtained and compared with Monte Carlo based calculations, illustrating the accuracy of the proposed scheme.
Steady state thermal-hydraulic analysis for the ETRR-2 Research Reactor
Authors: Abdelrazek I. D. , Khalil M. Y. , Shaat M. K. , Shokr A. M. 
Published: December 2013

Abstract
A steady state thermal-hydraulic analysis for the ETRR-2 Research Reactor has been performed using the computer code TERMIC. The analysis has included both, the verification of the core design as well as the performance of the equilibrium core. The uncertainties due to fuel fabrication tolerances, possible deviations in the operational measurements, the errors in the experimental correlations used in the analysis, and the errors due to simplifications made in the calculations have been considered in the analysis. A methodology based on uncertainties propagation has been adopted for the evaluation of hot channel factors. The results of the thermal-hydraulic analysis show that the reactor can be operated at full power level with sufficient safety margins against the thermal-hydraulic critical phenomena.
Analysis on special two-phase flow instabilities at full power natural circulation reactor condition
Authors: Zhang Y. J. , Yang X. T. , Jiang S. Y. 
Published: December 2013

Abstract
The experiments were performed on the test loop HRTL-5, which simulates the geometry and system design of the 5 MW nuclear heating reactor. In a wide range of inlet sub-cooling various flow instabilities were observed at p = 0.1 MPa and p = 1.5 MPa. Because of the different geometry design and operating conditions between the heating reactors and the boiling water reactors, the flow behavior presents great difference. Analysis shows: (1) under heating reactor conditions, sub-cooled boiling, condensation and void flashing are the fundamental thermodynamic processes; (2) sub-cooled boiling, condensation, void flashing and the compressibility of the steam space play an important role in the flow instabilities of the natural circulation system; (3) sub-cooled boiling instability, flashing instability, and flow excursion are the special instabilities at nuclear heating reactor conditions.
Dynamics of radionuclides in forest ecosystems
Authors: Steiner M. 
Published: December 2013

Abstract
The unique physiology and the layered structure of forest ecosystems result in dynamic transport and transfer processes which greatly differ from those in agricultural ecosystems. Radionuclides are retained in the upper organic horizons of forest soil for several decades and remain highly available for uptake by fungi and green plants. Contamination levels of mushrooms and game may therefore by far exceed those of agricultural produce. The efficient cycling of nutrients and radionuclides, which is characteristic for ecosystems poor in nutrients, can largely be attributed to forest soil with its complex and multi-layered structure and fungal activity. Fungi directly affect dynamic processes, playing a key role in the mobilization, uptake and translocation of nutrients and radionuclides. Fungal fruit bodies may be highly contaminated foodstuff and fodder. They are most likely the cause of the surprising trend of increasing contamination of wild boar which has been observed in the last few years in Germany. This paper is intended to give a qualitative survey of dynamic transport processes in forests and their relevance for radiation exposure to man.
Fast determination of strontium radionuclides in milk with the aid of the cryptand 2.2.2
Authors: Tait D. , Haase G. , Hartmann R. 
Published: December 2013

Abstract
A rapid method for separating strontium (Sr) radionuclides from liquid milk has been improved and tested for the determination of Sr-90 in milk. The method is based on the specific extraction of Sr from the milk with cryptand 2.2.2 on a cation exchange resin (Dowex Marathon C). Decontamination from other radionuclides such as those of caesium and from chemically similar elements such as calcium and barium is efficient. At least 6 samples can be treated in one day by one person. Tests were carried out on series of six 1.0 and 0.10 litre milk samples representing respectively routine milk samples and samples for fast analysis i.e milk contaminated with fresh fallout, including Ba-140, and requiring barium separation. For the 1.0 litre samples Sr recoveries ranged from 75–85 % while for 0.10 liter samples the range was 65–80 %. Conditions for the use of Sr-85 as yield tracer to correct for the losses were established. The method minimizes the handling of hazardous reagents.
Results of the investigation on natural radiation exposure due to ingestion
Authors: Wichterey K. , Beyermann M. , Kümmel M. 
Published: December 2013

Abstract
Results of a nationwide measuring programme in Germany are presented where long-lived natural radionuclides of the uranium and thorium series in samples of daily total diet were analysed. Typical ranges and average values of the specific activities are given. There are neither differences between the specific activities in total diet for adults and the age group ≤1 year nor meaningful regional differences. The resulting dose due to ingestion of natural radionuclides has been deduced for all age groups and evaluated. The radionuclides 210Pb, 210Po, 228Ra and 226Ra are responsible for about 90 % of the total ingestion dose which is 0.09 mSv per year on average without 40K contribution.