bluuebunny/crossref_metadata_2025 huggingface dataset:
Cyclic Softening Behaviour of a Duplex Stainless Steel
Authors: Evrard Pierre , Aubin Véronique , Degallaix-Moreuil Suzanne , Kondo Djimedo , Alvarez-Armas Iris
Published: December 2013

This second part aims to propose an extension of the bi-phased polycrystalline model shown in a previous contribution [1], in order to simulate the cyclic softening observed in an austenitic-ferritic stainless steel under uniaxial and non-proportional biaxial cyclic loading [2]. Assuming that the cyclic softening for uniaxial and biaxial non-proportional cyclic loading is due to a rearrangement of dislocations in hard (rich in dislocations) and soft (poor in dislocations) zones in ferritic grains [3], the ferritic single crystal law is modified. The new model parameters are identified from TEM observations [3] and by inverse procedure. Finally, the new model is validated for other cyclic loading paths. A good agreement is observed between simulation and experimental data.
Stress Analyses Around Holes of Plates for Different Types of Materials
Authors: Hedia Hassan S. , Najjar Ismail M. R. , Elmidany Tawfik T. , Kamel Madiha M.
Published: December 2013

Among the most important elements in aircraft structures are joints for transferring loads. An accurate assessment of the stresses for joints is essential for reliable strength evaluation and failure prediction. The aim of this work is to compare different types of materials, i.e. isotropic, laminated, and functionally graded materials (FGM), and different types of laminates, considering the ratio of stresses generated around a hole in a plate and the applied stress. The finite element method (FEM) is used to evaluate the stresses around a hole for the three types of materials when the plate is subjected to tensile stress, heating, and both heating and tensile stress. Utilizing the ANSYS package, the target of the study was to investigate the validity of the method. The results obtained for the laminated plate are compared to those obtained by E. Pan, and Rybiki & Hopper for both (90/0)s and (—45/45)s laminates. By similar results, it was shown that the laminates can withstand loads better than isotropic materials or FGM.
Optimal Material Distribution of a Micro-Gripper Manipulator with Straight-Line Path and Parallel Movements
Authors: Helal Mahmoud , Sun Lining , Chen Liguo
Published: December 2013

Micro electro-mechanical systems (MEMS) are miniaturized devices that consist of both mechanical and electrical parts. Compliant mechanisms have made an enormous contribution in the design process of various fields such as adaptive structures, hand-held tools, components in transportations, electronics and medical tools. The use of compliant mechanisms will help in reducing the number of components, as a result decreasing manufacturing cost and increasing the performance. The topology optimization methods search for an ideal material distribution of a structure. In this investigation, a new two-dimensional micro-grippers compliant mechanism, which can realize a straight-line path and parallel movement arms, are developed. Material models, which parameterize stiffness and density properties, are implemented based on the well-known solid isotropic materials with penalization model. Optimality criteria method is applied as the optimization algorithm using the ANSYS package. The micro-grippers with compliant mechanism can be applied to targets with a diameter of up to 400 μm.
Influence of Tool Geometry on Microstructure and Mechanical Properties of a Friction Stir Welded 7075 Aluminum Alloy
Authors: Sayer Sami , Yeni Qinar
Published: December 2013

The effectiveness of a friction stir welded joint is strongly dependent on several process parameters such as the tool geometry, including the height and the shape of the pin and the shoulder surface of the tool. In this study, two pin parameters, namely the pitch dimension (1.25 and 0.75 mm) and the helix angle (right and left helices), are varied in order to study their influence on the micro-structural, hardness, and tensile properties of friction stir welded 6 mm thick aluminum alloy 7075. The results reveal that the best combination has been obtained when welding with a pitch dimension of 0.75 mm using a right helix pin.
Uncertainty Estimation of Coating Thickness Measurement Results
Authors: Runje Biserka , Baršić Gorana , Alar Željko
Published: December 2013

This contribution presents an estimation of the measurement uncertainty of coating thickness measurement results. The measurements were performed on a steel sheet sample with an outside shell plating. The sample is protected against corrosion with two layers of 100 ¼m thick dry film. In the present case, the criteria of “80-20” have been applied. The measurement uncertainty evaluation has been carried out using Monte Carlo simulations (MCS method) in accordance with the document OIML G 1-101 Edition 2008 (E) Evaluation of Measurement Data – Supplement 1 to the Guide to the Expression of Uncertainty in Measurement – Propagation of Distributions Using a Monte Carlo Method. The criteria “80-20” was evaluated based on the mean coating thickness measurement results, as well as, on the basis of the complete measuring information. Aside from the expected value, complete measuring information comprises the value of measurement uncertainty. In the case where measurement result is described only as the mean of the measurement values a wrong conclusion regarding the fulfillment “80-20” is reached.
Einfluss des Warmauslagerns auf das Gefüge sowie auf die mechanischen und tribologischen Eigenschaften eines Duplexstahles
Authors: Turhan Hüseyin
Published: December 2013

Kurzfassung

Für den vorliegenden Beitrag wurde der Einfluss der Wärmebehandlung auf das Gefüge eines hochlegierten austenitisch-ferritischen Duplexstahles untersucht. Außerdem wurde der Einfluss des Homogenisierens und des Alterns auf das Werkstoffverhalten ermittelt. Die Proben wurden entsprechend ASME 1883 vorbereitet. Sie enthielten neben einem niedrigen Molybdängehalt höhere Kohlenstoff-, Chrom- und Nickelanteile. Nach dem Homogenisieren bei 1060 °C wurden die Proben der Reihe nach auf 475, 650 und 850°C erwärmt, bei diesen Temperaturen jeweils 80 h gealtert und danach in einem Eiswasserbad mit 3,5% NaCl rasch abgekühlt. Danach wurden das Gefüge und die mechanischen Eigenschaften des Werkstoffes untersucht. Bei den mechanischen Eigenschaften des Werkstoffes wurden viele und wichtige Unterschiede gefunden. Außerdem wurden alle Proben zur Bestimmung der intermetallischen Phasen und der Karbide lichtmikroskopisch, röntgenografisch und elektronenmikroskopisch untersucht. Aus den DTA-Kurven geht hervor, dass zwischen den Temperaturen von 1100 und 1221°C nur ein Umwandlungspeak existiert. Die ferritische und die austenitische Phase lösten sich in diesem Temperaturbereich auf und wandelten sich ausschließlich in Ferrit um.
Ein verbessertes Verfahren zur Lebensdauerabschätzung mittels linearer Schadensakkumulation
Authors: Hinkelmann Karsten , Esderts Alfons , Zenner Harald
Published: December 2013

Kurzfassung

Ermüdungsfestigkeitsnachweise von Bauteilen werden häufig nach dem Nennspannungskonzept bzw. dem örtlichen Spannungskonzept geführt. Einen zentralen Punkt dieser Konzepte bildet die lineare Schadensakkumulation nach Palmgren und Miner (Miner-Regel). Statistische Auswertungen zeigen, dass die Lebensdauerabschätzung nach der linearen Schadensakkumulation im Mittel auf der unsicheren Seite liegt und eine höhere Treffsicherheit wünschenswert ist. Durch die Anwendung effektiver Schadenssummen kann die mittlere Lebensdauerüberschätzung korrigiert werden. Im Einzelfall kann es dennoch zu größeren Abweichungen zwischen Rechnung und Versuch kommen.

Zur Verbesserung der Lebensdauerabschätzung mittels linearer Schadensakkumulation werden zwei Lebensdauerkorrekturverfahren vorgestellt. Die Anpassung der rechnerischen Gaßnerlinie an Versuchsergebnisse erfolgt in Abhängigkeit von der Kollektivform und der Wöhlerlinienneigung durch einen Lebensdauerkorrekturexponenten anstatt einer (multiplikativen) konstanten effektiven Schadenssumme. Neben der höheren Treffsicherheit wird der Übergang der Gaßnerlinie in die Wöhlerlinie für Rechteckkollektive sichergestellt.
Cellular Aluminium Foam Metal Production with Space Holder Particles
Authors: Ozer Gökhan , Güler Kerem Altug , Taslicukur Zeynep
Published: December 2013

Metal foams are a new class of materials with low densities and novel physical, mechanical, thermal, electrical, and acoustic properties. Aluminum foams especially show potential for use in lightweight structures, for energy absorption, and for thermal management. Open cell aluminum foams with tailored porous morphology were synthesized by a space-holder method. In these foams, the pore shape is predominantly controlled by the initial shape of the space-holder particles that are used to produce the preform. In this study, resin bonded sand and gypsum bonded ceramic space holder particles are used in the open cell foam production. This paper describes the space-holder method for manufacturing open cell aluminum foams and characterizes the density as well as the compressive property of the foams.
Einsatz neuer Werkstoffe für die Weiche — Erfahrungen aus der Sicht des Anwenders*
Authors: Zoll Andreas
Published: December 2013

Kurzfassung

In den zurückliegenden Jahrzehnten hat die Werkstoff-Beanspruchung durch die Erhöhung der Radsatzlasten und Geschwindigkeiten zugenommen, wodurch die herkömmlichen Werkstoffe für Rad, Schiene und Weichenfahrbahn schneller an die Grenzen ihrer Belastbarkeit gelangten. Dies legte neben der konstruktiven Modifikation des Überlaufbereiches von Weichen auch den Einsatz höherfester Werkstoffe nahe. Für Schienen in Gleis und Weiche sowie für Weichenherzstücke wurden bei der Deutschen Bahn AG in den vergangenen Jahren anhand von Prüfstands- und Gleisversuchen zahlreiche Werkstoffkonzepte für perlitische und bainitische Stähle einer vergleichenden Bewertung unterzogen. Das Ziel bestand darin, die verschieden belasteten Fahrbahnsegmente bei der Entwicklung ihrer symptomatischen Schädigungen zu beeinflussen.
Ablauf einer sicheren Auslegungsberechnung von Getriebegehäusen aus Aluminiumdruckguss*
Authors: Varenkamp Marco , Schön Michael
Published: December 2013

Kurzfassung

Die Herausforderung bei der Lebensdauerberechnung von Getriebegehäusen aus Aluminiumdruckguss ist zum einen die komplexe Bauteilgeometrie und zum anderen der bedingt durch den Herstellprozess fehlerbehaftete Werkstoff. Die Berechnung erfolgt mittels FEM und Örtlichem Konzept. Das Übertragbarkeitsproblem des Örtlichen Konzeptes wurde durch Abgleiche mit Bauteilversuchen und Optimierung der Übertragungsfunktionen auf Basis statistischer Betrachtungen gemeistert. Die sichere Auslegung wird durch einen Sicherheitsfaktor gewährleistet, der aus der Vertrauenswahrscheinlichkeit der Berechnungsergebnisse hergeleitet wird. Anhand eines Beispiels wird der Ablauf näher erläutert. Darüber hinaus wird gezeigt, dass das Berechnungsergebnis bei mehrstufig einachsiger Belastung durch Verwendung des Schädigungsparameters PJ verbessert werden kann.
General Standard for Welding Simulation*
Authors: Schwenk Christopher , Tikhomirov Dmitrij , Esser Gerd , Rethmeier Michael
Published: December 2013

For differentiating the applicability of various numerical welding simulation methods as well as unifying the prerequisites and the steps to be taken in simulation, normative codes are required for the user. Since any standard-like documents are currently still lacking in this field, the DIN German Institute for Standardization in partnership with the Research Association of DVS German Welding Society have set up a standards committee dealing with the preparation of respective documents.

This article focuses on the presentation of the new DIN Spec 32534-1 explaining the major simulation steps and specifying the application fields and the key terms of welding simulation. In addition, a generally valid simulation structure has been established which is intended to serve as a recommendation for customers and suppliers in formulating and handling a service order as well as for persons who start doing welding simulation for the first time. It additionally gives an overview of the other subject areas dealt with in the standards committee as well as of the international activities in this field.
DIN EN ISO 6892-1:2009 Der Zugversuch — Erste Erfahrungen aus der praktischen Umsetzung der neuen Norm*
Authors: Aegerter Johannes , Kühn Hans-Joachim , Frenz Holger , Weißmüller Christian
Published: December 2013

Kurzfassung

Mit der Veröffentlichung der DIN EN ISO 6892-1:2009 [1] wurde für den Zugversuch bei Raumtemperatur eine Harmonisierung der in Europa verbindlichen EN 10002-1:2001 [2] mit der ISO 6892:1998 [3] erreicht. Wesentliche Änderungen sind die Einführung der Dehngeschwindigkeit und der Dehngeschwindigkeitsregelung als maßgebliche Prüfgeschwindigkeit bzw. Regelungsart, als Verfahren A bezeichnet. Mit der korrekten Anwendung dieses Verfahrens wird gewährleistet, dass im Moment der Kennwerteermittlung bei enger spezifizierten zulässigen Dehngeschwindigkeitsbereichen vergleichbare resultierende Dehngeschwindigkeiten an der Probe auch bei unterschiedlichen Steifigkeiten der Prüfaufbauten vorliegen. Dieses führt besonders bei dehngeschwindigkeitssensitiven Werkstoffen zu deutlich vergleichbareren Ergebnissen. In diesem Beitrag wird auf die Notwendigkeit der Einführung des Verfahrens A, der möglichen Umsetzungen auch bei Verwendung von älteren Prüfsystemen sowie exemplarisch auf vergleichende Ergebnisse der Verfahren an einem dehngeschwindigkeitssensitivem Stahlwerkstoff eingegangen.
Ausgewählte Schadensfälle aus dem Großgasturbinenbau – Werden wir aus Schaden wirklich klug?*
Authors: Neidel Andreas , Völker Jörg
Published: December 2013

Kurzfassung

Nach einer kurzen Beschreibung der gasturbinentypischen Leistungsmerkmale und der sich daraus ergebenden spezifischen Bauteilbeanspruchungen zeigt der Beitrag anhand einiger Fallstudien konstruktions-, fertigungs-, montage- und betriebsbedingte Komponentenschäden, die an großen Industriegasturbinen im Laufe ihrer Lebensdauer „von der Wiege bis zur Bahre“, d. h. vom „Reißbrett“ bis zur Revision im Kraftwerk, auftreten können. Folgt man der Terminologie in der angelsächsischen Literatur, die neuerdings zwischen werkstofftechnischem Schadensmechanismus (Physical oder Metallurgical Cause of Failure, z. B. Schwingungsrisskorrosion), Primärursache (Primary Cause of Failure, z. B. zu festes Anziehen einer Rohrverschraubung bei der Montage), Systemursache (Root Cause of Failure, z. B. Verwendung eines falschen Dichtungsmaterials) und organisatorischer Ursache (Organizational Cause of Failure, z. B. fehlende Schulung des Personals) unterscheidet, so beziehen sich die Laboruntersuchungen der Autoren ausschließlich auf erstere Kategorie, wobei die anderen drei zumindest mit erwähnt werden. Vornehmstes Ziel jeder Schadensanalyse ist die Vermeidung von Wiederholfällen, also eines erneuten Schadenseintritts an gleichen Bauteilen unter denselben Bedingungen wie beim Erstschaden. Um „aus Schaden klug zu werden“ sei die Fachgemeinde ausdrücklich ermutigt, in geeigneter Weise noch mehr als bisher über eigene Schadensuntersuchungen zu berichten. Restriktionen und Veröffentlichungsverbote, denen der Schadensanalytiker mitunter begegnet, laufen diesem Ziel zuwider.
Effects of Welding Parameters on the Mechanical Properties of Inert Gas Welded 6063 Aluminum Alloys
Authors: Ertan Taner , Ertan Rukiye , Uguz Agah
Published: December 2013

The influence of welding parameters, namely welding current and gas flow rate, on the mechanical properties of Gas Tungsten Arc Welding (GTAW) and Shielded Metal Arc Welding (SMAW) welded 6063 Aluminum alloy (AA 6063) has been investigated. In order to study the effect of the welding current and gas flow rate, microstructural examination, hardness measurements and room temperature tensile tests have been carried out. The experimental results show that the mechanical properties of GTAW welded joints have better mechanical properties than those of SMAW welded joints. Increasing the welding current appeared to have a beneficial effect on the mechanical properties. However, either increasing or decreasing the gas flow rate resulted in a decrease of hardness and tensile strength. It was also found that, the highest strength was obtained in GTAW welded samples at 220 A and 15 l/min gas flow rate.
Optimisation of GTAW Parameters for the Tensile Strength of AISI 304 Stainless Steel Welds Using the Taguchi Method
Authors: Ertan Rukiye
Published: December 2013

The influence of welding parameters, i. e. the welding current, root gap and the shielding gas flow rate, on the tensile strength of AISI 304 austenitic stainless steel welded with gas tungsten arc welding was investigated. To determine the optimum levels of the parameters, the Taguchi approach was used to increase the tensile strength. The results were analysed by investigating the variance by which welding parameters significantly affect the response. Mathematical models were developed to describe the influence of the selected parameters on the tensile strength. The results were confirmed by experiments.
Microstructural Studies on New Developed Niobium Cast High Speed Tool Steel
Authors: Yilmaz Alpay
Published: December 2013

High speed tool steels, widely used for tools, are characterized of excellent hardness, wear resistance, and high temperature properties. These steels are used not only for metal cutting but also in wood, textile, and leather industries. As in cast and wrought materials, high speed tool steels show a broader application range compared to tool materials which are produced by powder metallurgy. However, the production from bulk material requires high machining costs in the case of specially formed tools. Here is discussed that a new alloying design with niobium differing from known high speed steel chemical alloying designs is created and the production of high speed tool steels in as cast condition without hot working. The microstructure is modified by adding niobium and applying proper heat treatment to get blocky type small monocarbides ending up with providing high toughness and preventing the eutectic carbides which are situated in the interdendritic areas and which increase brittleness between dendrites in the as-cast structure.
Microstructural and Mechanical Properties of Pure Aluminum, 5083 and 7075 Alloys Joined by Friction Stir Welding
Authors: Yilmaz Selim Sarper
Published: December 2013

In this study, microstructural and mechanical properties of pure aluminum, 5083 and 7075 alloys joined by friction stir welding were investigated. Hardness, tensile, bending and impact tests were applied to the welded samples. In addition, optical and SEM tests were carried out. The effects of welding speed on microstructure and mechanical properties were investigated in these materials. Then, the optimal conditions for friction stir welding were determined for pure aluminum, 5083 and 7075 alloys. The maximum hardness was observed for 7075 while the minimum hardness was observed for pure aluminum.
The Effect of the Retrogression Process on the Wear Behaviour of a 7075 Aluminium Alloy
Authors: Durmus Hülya , Uzun Recep Onur , Şahin Salim , Yüksel Nilay
Published: December 2013

Retrogression and re-aging (RRA) process are applied in an attempt to enhance mechanical properties and corrosion resistance of 7075 aluminium alloys. In this study, retrogression and re-aging process have been applied to a 7075 aluminium alloy at 170°C for 5, 40, 80 min and wear resistance of RRA applied samples have been investigated by ball-on-disc wear test apparatus. Sliding distance has been chosen as 300 meters. Re-aging procedure has been carried out at 125°C for 10, 20 and 30 hours. Minimum wear loss has been obtained by retrogression for 40 min and aging for 30 hours.
Recycling of Aluminium Alloy Scraps by Pressure-Assisted Investment Casting for Aluminium Foam Manufacture
Authors: Asavavisithchai Seksak , Jareankieathbovorn Natthida , Srichaiyaperk Areeya
Published: December 2013

Recycling of ADC12 alloy scraps for fabrication of open-cell aluminium foams has been conducted via pressure infiltration method of replication process. The scrap, up to 50 wt.-%, was melted with pure aluminium billet, followed by infiltration in a replicated mold of polyethylene foam structure. Compared with the pure aluminium foam, the compressive strength and hardness are higher the foams with recycled scraps of. The improvement of mechanical properties is due to the presence of Si hard phase in Al matrix. The strength and hardness of the foams also increase with increasing content of scrap.
Effects of Co as an Alloying Element and Heat Treatment Processes on the Properties of High Speed Steels
Authors: Toptop Guven Orkun , Kisasoz Alptekin , Karaaslan Ahmet
Published: December 2013

In this study, effects of Co as an alloying element and different heat treatments processes on the properties of DIN 1.3243 and 1.3343 were investigated. Austenitising and tempering temperatures are critical parameters for steel hardening. Also, Co has critical effect on mechanical properties of high speed steels. Samples were subjected to two different austenitising temperatures with two tempering temperatures. Effects of process parameters on the mechanical properties and tooling abilities of the specimens were investigated. Specimens were characterized by Rockwell hardness tests and tooling abilities of the specimen were determined by characterizing the number of screws that were fabricated with specimens. According to results of experiments, Co has any effect on the hardness of specimens after the austenitising and tempering processes. Moreover, tool life of the specimens were increased by the higher hardening temperatures, the lower tempering temperatures and the presence of Co as an alloying element, because of the positive effect of Co on the hot hardness and hot strength.
Energy Efficient Multiaxial Resonance Test Systems – New Applications and Testing Methods*
Authors: Henze Sven , Hug Joachim , Zorrmann Helge , Scholz Angelina
Published: December 2013

Modern lightweight design is only feasible exploiting properties of geometry and material. In some applications an uniaxial loading of components is not sufficient and a multiaxial loading of forces or moments becomes necessary. In terms of decreasing development cycles and resultant increasing demands on testing frequencies, multiaxial resonance test systems turn into fast, economically advantageous and energyefficient development tools. Well known problems as interference of actuators were solved by the use of particular decoupling devices. Innovative electronic systems and software applications allow matching or different frequencies for each load directions with variable amplitude ratios. Moreover, the phase between the different loading directions is freely adjustable. This development yielded the two-axial crankshaft test, the multiaxial bearing test system, the four point rotating bending rig with superimposed torsion and the multiaxial resonance actuator.
Multi-Level Porosity Silver Foams by Powder Processing Method
Authors: Preuksarattanawut Thanachache , Nisaratanaporn Ekasit , Asavavisithchai Seksak
Published: December 2013

Silver foams with 70% porosity have been produced by the sintering and dissolution process (SDP) of fine silver powder. The powder was obtained from the reduction of rod-shaped silver sulfate, using glycerol mixed with sodium hydroxide as reducer and reaction accelerator, respectively. The foam shows three-level porosities, ranging from nanometer to millimeter level. The nanopores were created during the reduction process. The micropores were formed by the dissolution of remaining silver sulfate. The millipores were made from the removal of disaccharide powders. The pore architecture is unique and can be tailored by varying material and process parameters such as silver sulfate and disaccharide morphologies, reduction temperature and time as well as volume fraction of materials.
Use of Grey-Taguchi Method for the Optimization of Oblique Turning Process of AZ91D Magnesium Alloy
Authors: Buldum Bariş , Eşme Uğur , Kemal Külekci Mustafa , Şik Aydin , Kazançoğlu Yiğit
Published: December 2013

This study investigated the multi-response optimization of turning process for an optimal parametric combination to yield minimum cutting forces and surface roughness with maximum material removal rate (MRR) using the combination of Grey relational analysis (GRA) and Taguchi method. Nine experimental runs based on an orthogonal array of Taguchi method were performed to derive objective functions to be optimized within experimental domain. The objective functions have been selected in relation to parameters of cutting process: cutting force, surface roughness and MRR. The Taguchi approach followed by Grey relational analysis to solve the multi-response optimization problem. The significance of factors on overall quality characteristics of the cutting process has also been evaluated quantitatively by the analysis of variance method (ANOVA). Optimal results have been verified through additional experiments. This shows proper selection of the cutting parameters produces, high material removal rate with better surface roughness and lower cutting force.
A New Design of Hip Prosthesis Coating using Functionally Graded Material
Authors: Hedia Hassan S. , Fouda Noha
Published: December 2013

Titanium and its alloys which have been widely used in many prostheses carry the major joint load and cause stress shielding. Thus, the bone might become osteoporotic due to lack of physiological stress flow in common hip replacement. Therefore, the optimization of hip joint materials is one of the most challenging tasks in prosthetic design. It is found in the literature that there is a great contradiction regarding the use of hydroxyapatite (HAP) coating. In this study a finite element analysis (FEA) and optimization techniques have been carried out in order to find a new design of hip stem coating using functionally graded material (FGM) to reduce stress shielding at the proximal medial part of the femur, as well as reducing the interface shear stress at the interface between the coating and the bone which directly affects the implantation and long-term stability. This work is divided into two parts: in the first part, the gradation of the elastic modulus of the coating material has been changed in the vertical direction, while the second part changes the elastic modulus in the horizontal direction. The optimal design of the first and second models was compared with HAP coating and with homogenous uncoated titanium stem. The design optimization of the first model revealed, using a coating material consisting of HAP at the upper layer of the coating graded to collagen at the lower layer, increases the maximum von Mises stress in bone at the proximal medial part of the femur by 65% and 19% compared to titanium stem and titanium coated with HAP, respectively. The maximum lateral interface shear stress in the bone at the bone/coating interface is reduced by 23% and 12%, respectively. However, the maximum medial interface shear stress in the bone at the bone/coating interface is reduced by 39% and 14% compared to titanium stem and titanium coated with HAP, respectively. The design optimization of the second model revealed, using a coating material consisting of collagen at the inner layer adjacent to stem graded to HAP at the outer layer adjacent to bone, increases the maximum von Mises stress at the proximal medial part of the femur by 60% and 15% compared to titanium stem and titanium coated with HAP, respectively. The maximum lateral interface shear stress is reduced by 18% and 6%, respectively. However, the maximum medial interface shear stress is reduced by 35% and 8% compared to titanium stem and titanium coated with HAP, respectively.
Influence of Deformation on the Phase Structure of a 30CrMnSi Steel
Authors: Skakov Mazhyn , Uazyrkhanova Gulzhaz , Popova Natalya , Scheffler Michael
Published: December 2013

The grainary substructure of 30CrMnSi steel has been studied after rolling deformation. It has been found that in the studied material the bulk share of anisotropic grains amounts to 25% and the isotropic grains to 75%. It has been observed that the martensitic structure is completely broken in the rolling process.
Electrolytic Recovery of Tin from Waste Lead Frames: Use of Aqueous HCl Leaching Solution as Electrolyte
Authors: Kang Kyung-Hoon , Kim Beomseok , Seo Min Hye , Cho Sung-Su , Lee Sungkyu , Hong Hyun Seon
Published: December 2013

Lead frames are generated in large quantities by modern semiconductor packaging industry and they contain significant concentrations of valuable tin, nickel, and copper. For electrowinning of tin from waste lead frames, hydrochloric acid leaching of tin is quite advantageous, but solution stability, electrolytic efficiency and deposit morphology should be optimized before commercialization. HCl electrolyte was diluted (distilled water: HCl = 350:150) for electrowinning of waste lead frames at 40 °C with 0.2 A/cm2 and Ti-Ir cathode. After 4 h electrowinning, 99% pure Sn with 99.1% recovery rate was produced. Therefore, aqueous HCl electrolyte was quite effective for electrowinning of Sn leaching solution, and a higher recovery rate of purer Sn within shorter electrowinning time was obtained.
Statistical Interactions in Phosphate Rock Calcination
Authors: Al-Fariss T.F. , Abd El-Aleem F.A. , El-Midany A.A.
Published: December 2013

Most of the marine phosphate deposits are calcareous phosphates. Calcination process is one of the famous processes used for upgrading sedimentary calcareous phosphate ore. In this study, evaluation of the calcination process performance in terms of its operating parameters was carried out. The effect of operating parameters and their significance on calcination of calcite as a main phosphate ore impurity was studied using statistical design of experiments. A statistical model was developed to correlate the studied parameters with the phosphate grade in the calcined product. The studied parameters were temperature, time, and particle size. The analysis of the design results showed that the tempe­rature is the most significant parameter. The higher the temperature is the higher the calcite conversion to calcium oxide and release of carbon dioxide. In addition, the particle size plays a significant role in contact area between particles as well as the voids among them that help to release the CO2faster. Moreover, a phosphate concentrate, suitable for phosphoric acid production, containing ∼32 % P2O5can be achieved at optimum values of studied parameters, i. e., at a temperature of 850 °C, after a calculation time of 40 minutes and with a particle size of 0.074 mm, respectively. Furthermore, quenching and slacking of calcined products increased the grade by 2–3 % to reach 34 % to 35 % P2O5in the final concentrate.
Einfluss der Verformungsgeschwindigkeit und des Feuchtegehaltes auf das quasistatische Verformungsverhalten technischer Vulkanfiber∗
Authors: Penning Bastian , Walther Frank , Dumke Dominik , Künne Bernd
Published: December 2013

Ein detailliertes Wissen über die Werkstoffeigenschaften stellt für Konstrukteure und Fertigungsingenieure die Grundvoraussetzung zur Gewährleistung eines sicheren und wirtschaftlichen Betriebs von Bauteilen dar. Ziel dieser Untersuchung ist es, den nur wenig untersuchten Konstruktionswerkstoff Vulkanfiber hinsichtlich des Einflusses der Verformungsgeschwindigkeit und des Feuchtegehaltes auf die quasistatischen Eigenschaften mikrostrukturbasiert zu charakterisieren und zu bewerten. Neben materialografischen und mikroskopischen Einrichtungen wurden ein Ultramikrohärteprüfsystem sowie zur mechanischen Charakterisierung eine elektromechanische Universalprüfmaschine, ein taktiles und ein Videoextensometer, Thermoelemente und ein Thermografiesystem sowie eine Hochgeschwindigkeitskamera zur Detektierung des Rissbildungs- und -ausbreitungsverhaltens eingesetzt.
Evaluation of Geometric Accuracy and Thickness Variation in Incremental Sheet Forming Process
Authors: Durgun Ismail
Published: December 2013

The aim of this study is to evaluate dimensional conformity and thickness variation of a pyramid geometry obtained by negative single point incremental sheet forming. DC04 mild steel, which has been widely used in automotive and numerous applications due to high formability, was used for experimental investigations. Dimensional accuracy of whole geometry and surface roughness are investigated under the influence of toolpath parameters such as tool diameter, feed rate and vertical step down. In this paper, geometric accuracy and thickness are evaluated by production tolerances of conventional methods and results show that thickness reduction of formed sheet and geometrical deviation of side faces are out of tolerance for all cases.
Effect of Plasma Nitriding Parameters on the Wear Behaviour of AISI D6 Tool Steel
Authors: Korkmaz Ersin Eser , Bayram Ali , Ertan Rukiye , Yavuz Nurettin
Published: December 2013

In the present investigation, the effects of plasma nitriding pressure and time on the structural and tribological characterization of AISI D6 grade cold work tool steel were studied. DC glow discharge plasma nitriding process under NH3 gas was performed at temperatures of 500 °C and at pressures of 150 Pa, 450 Pa and 800 Pa for durations of 2 h, 7 h and 10 h. The mass loss and the coefficient of friction were measured using a ball-on-disc wear test with 1.668 N, 4.143 N, and 9.113 N test loads. Cross-section and surface characterizations were evaluated using optical microscopy, SEM, and microhardness test techniques. The surface microhardness was found to increase with the nitriding time and the pressure. The wear resistance of the specimen strongly depends on the nitriding parameters and the applied test load in determining whether a plastic deformation of the surface layer has occurred or not.
Investigation of Modal Properties of AlSi7 Foam Produced by Powder Metallurgy Technique
Authors: Uzun Arif , Gökmen Uğur , Cinici Hanifi , Koruk Hasan , Turker Mehmet
Published: December 2013

The modal properties of aluminum-based (AlSi7) metallic foam, produced by powder metallurgy technique, as a function of foam density (and thus pore size and amount of porosity) were investigated. In the experimental studies, 1 wt.-% TiH2 and 7 wt.-% Si powders were added to aluminum powder and they were mixed in a three dimensional turbola mixer for 30 minutes. Mixed powders were compacted, extruded and rolled to produce the precursor samples. AlSi7 foam samples with the dimensions of 18.7 cm × 2.6 cm × 1.6 cm were produced after foaming at 690 °C. After all, the natural frequencies and the modal loss factors of a few foam samples with different pore distributions and/or densities were determined using the frequency response functions measured on the test samples. The results show that the densities of the foam samples decrease with increasing pore size and amount of porosity, and the modal loss factors of foam samples increase as foam density decreases.
“Vertical Dimensions” of Pulsed Laser Welding
Authors: Çelen Serap , Karadeniz Süleyman
Published: December 2013

Laser welding, perhaps the most prominent tool for modern manufacturing systems, enable the performance of safe and sound weldments with operational reliability. Thus, the use of lasers provides economical efficiency via quantitative increase of production with quality improvement, and shortening the required welding process time. Laser welding can readily be used at pulsed and continuous mode with assisted systems. It may be time for a paradigm shift and for an exploration of new viewpoints with regarding its distinctive features. In the present investigation, we go beyond current classical approach by presenting novel features of laser welding included in these experiments. Thus, the purpose of this manuscript is to consolidate a proposal for reducing the time for pulsed laser welding with a novel design approach which can be called “vertical dimensions”. This method can facilitate the human processes of making decisions for setting unknown parameters and shorten their process time by actively reducing operations with creating a unique approach. We characterize our resultant weld morphology of laser welds as a function of these vertical dimensions.
Simple formulas for conservatively calculating the fuel rod cladding strains due to RIA
Authors: Sauer G.
Published: December 2013

A set of formulas for conservatively computing the fuel rod cladding strains caused by short and intense energy pulses is presented. Such pulses may be the consequence of a RIA. The formulas are based on the theory of stresses and deformations of tubes loaded by internal pressure and stressed beyond the elastic limit. The known solutions of this theory are applied to compute the cladding strains due to the intense interaction between fuel and cladding during a RIA. Simple and easy to evaluate expressions for the strains are obtained. They enable to quickly assess the impact of any energy pulse for any burn-up state. The actual burn-up state of the fuel rod at the moment in which the occurrence of a RIA shall be simulated is described by only three data. These data can be calculated in an enveloping sense in advance and then be used to study energy pulses of any intensity. Besides the cladding strains induced by the fuel-cladding interaction the significance of the gas pressure in the rod and of gas swelling for the cladding strains is also addressed.
The time-dependent effect of the biological component of 137Cs soil contamination
Authors: Dederichs H. , Pillath J. , Lennartz R. , Hill P. , Hille R.
Published: December 2013

In investigations of the long-term development of the population dose in the highly contaminated regions of the Commonwealth of Independence States it was found that the external dose has not decreased as strongly as expected since 1992. Further investigations have shown that, contrary to expectations, no linear correlation can be observed between soil contamination and measured area dose rate. As a contribution towards clarifying these issues, the area dose rate and the soil contamination including the plant fraction were investigated in the Korma district, Belarus. It was found that it is necessary to cover and average over larger areas in order to determine from ground contamination the long-term development of the external dose commitment. This means that for this purpose the introduction of an “effective” surface contamination (sum of mineral and organic contamination components) is necessary. The phenomena observed are described in a model, which permits an analytical calculation of the contamination profile in soil taking migration and transfer effects into account. The differences observed between the measured soil contamination and the resulting external doses or the directly measured dose rate can be explained by the proposed model. Moreover, their long-term development can be calculated. The results show that a time decade after the accident the biological part of the “effective” soil contamination becomes dominant and cannot be neglected.
Calculation of the energy deposition in the targets from C to U irradiated with intermediate energy protons
Authors: Broeders C. H. M. , Konobeyev A. Yu. , Travleev A. A.
Published: December 2013

The energy deposition was calculated for the targets from carbon to uranium irradiated with intermediate energy protons with the help of different models incorporated in the MCNPX code package (Bertini, CEM and ISABEL) and with the help of the CASCADE/INPE code. The values obtained using the different models and codes are in a good agreement for all targets except uranium. The comparison with the available experimental data for the heat deposition for 0.8, 1.0 and 1.2 GeV protons has been performed. The good agreement is observed for copper, lead and bismuth target. The best result is obtained with the help of the ISABEL model. The systematic dependence of the heat deposition from atomic number of the target was investigated. The contribution of different particles and energy ranges in the heat deposition has been studied at the primary proton energies from 0.3 to 2.5 GeV.
U-Pb accelerator-driven sub-critical systems research at the proton beam of the JINR NUCLOTRON
Authors: Barashenkov V. S. , Kumawat H.
Published: December 2013

Neutron spectra, yields and energies of particles generated by a uranium electro-nuclear set-up which is now used in Dubna for transmutation research of various isotopes with a proton beam of an energy of 1–2 GeV, were analyzed by means of mathematical modelling based on the Monte Carlo code CASCADE. The influence of space dispersion on the proton beam and its possible deviation from the center of a lead target is investigated. It is shown that the polyethylene radiation shielding that is being used now, does not protect the measuring room from neutrons and γ-rays.
Monitoring and prediction of the dispersion of radioactive substances in German Federal waterways – concepts and methods
Authors: Dersch G. , Krause W. J.
Published: December 2013

Based on the Precautionary Radiation Protection Act, the Federal Institute of Hydrology (BfG) is the Federal Center for the monitoring of radioactivity of the German Federal Waterways. In this function, the Institute operates a Radioactivity Measuring and Sampling Network along the Federal Waterways. Priority monitoring tasks are the early warning, the determination of radionuclides in water, suspended solids and sediment (laboratory measurements) and the prediction of dispersion by means of dispersion investigations using tritium as a tracer. This report gives a survey on the present status of the concept and the methods used, as well as an outlook on their further development.
Combination of measurements and model predictions after a release of radionuclides
Authors: Gering F. , Richter K. , Müller H.
Published: December 2013

Model predictions for rapid assessment and prognosis of possible radiological consequences after an accidental release of radionuclides play an important role in nuclear emergency management. Radiological measurements (e. g., dose rate measurements, contamination measurements of foodstuffs) can be used to improve such model predictions. This paper describes a method for combining model predictions and measurements (data assimilation) in the deposition model and the food chain model of the European radiological decision support system RODOS. The data assimilation approach is based on the Ensemble Kalman Filter, a Monte Carlo variant of the Kalman filter.
German assistance for the dismantling of nuclear submarines in Russia
Authors: Hinsdorf H.-J.
Published: December 2013

On October 9, 2003, the German Ministry of Economics and Labor signed an agreement with the Russian Federation's former Ministry of Atomic Energy for support in eliminating the nuclear weapons that the Russian Federation has pledged to reduce through the dismantlement of decommissioned nuclear submarines. This treaty, which is binding under international law, implements the Global Partnership against the Spread of Weapons and Materials of Mass Destruction as agreed to at the G8 Summit in Kananaskis in 2002. The core element of the German-Russian project is the creation of a long-term interim storage facility for 120 nuclear submarine reactor compartments near Murmansk in northwestern Russia and the preparation of the reactor compartments for interim storage. This technically demanding project, which began not without some problems, has developed in a positive manner since the end of 2003. The provisions in the treaty and its supplementary documents, which were internationally publicized, have generally proven to be successful.
Semi-statistical mechanical fuel rod design
Authors: Sauer G.
Published: December 2013

A technique to combine statistical and deterministic approaches in mechanical fuel rod analysis is described. The impact of different fuel rod input parameters on the fuel rod design parameter under consideration is identified by statistical means. It is expressed through rank correlation coefficients. These coefficients are then employed to calculate corresponding quantiles for the input parameters allowing the selection of appropriate input values from the parameter probability distributions. The quantiles are computed with the provision that the fuel rod reactions obtained with the associated input parameter combination cover the reactions in a subset of the analysed fuel rod totality. The described procedure reduces the computational costs in comparison to some pure statistical methods of fuel rod design.
Fire hazard analysis at Ignalina Nuclear Power Plant
Authors: Poskas P. , Simonis V. , Zujus R. , Kilda R. , Sirvydas A. , Kolesnikovas J.
Published: December 2013

The fire hazard analysis methodology and main results of Ignalina Nuclear Power Plant RBMK-1500 type reactor's systems and rooms with safety elements and also rooms adjacent to main rooms and other fire hazardous rooms are presented. In total this concerns about 2100 rooms in the control area of one Unit, where the fire could influence nuclear safety of the power plant. For this purpose the decision-making computerized system FIRE-INPP was developed. It includes modules for recording necessary information, data processing, analysis and assessment on compliance of rooms at Ignalina NPP with national fire safety requirements and international recommendations regarding fire hazard. Screening algorithms and decision-making module are the basis for the decision-making computerized system, that allows to perform unambiguous, reliable and fast fire hazard analysis and give recommendations to ensure fire safety adequacy.
On the plane-wave theory in fertile uranium
Authors: Seifritz W.
Published: December 2013

The theory of the autocatalytic burn-wave phenomenon in fertile material for a 1D solitary plane-wave is summerized together with a variety of analytical approximations. It was found that the modified logarithmic product approximates best the fluence- and neutron flux shapes including their skewness – being absolutely necessary for a propagating burn-up wave. Due to the stability of these shapes they propagate isentropically: The deeper reason why we could harness the breeding principle without reprocessing.
Wavelet techniques for the determination of the decay ratio in boiling water reactors
Authors: Sunde C. , Pázsit I.
Published: December 2013

The usefulness of wavelet transform and wavelet filtering techniques for the improvement of the estimation of the decay ratio (DR), characterising the stability of BWRs, is discussed. There are two distinct areas investigated. The first concerns the improvement of the quality of the traditionally used auto-correlation function (ACF) for the estimation of the DR, by trend elimination and denoising. The subsequent estimation of the DR itself is made by traditional methods such as the peak-to-peak method or curve fitting. The second area is the estimation of the DR by the use of continuous wavelet transform. The possibility of estimating two different DRs in case of dual oscillations, and in particular the finding of the higher DR, is also investigated. It was found that wavelet pre-processing does not always improve the estimation of the ACF of a non-ideal signal, compared to other methods; but for signals containing various trends and data scatter in the ACF, it brings a noticeable improvement. As an extension of the discrete wavelet methods, the continuous wavelet transform appears to be a promising candidate to determine the critical DR even in the case of two oscillations being co-existent with different stability properties. The methods investigated or developed here were also tested on measured data from Swedish BWRs.