bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fracture Toughness Measurements on silicon carbide
Authors: Himsolt G. , Fett T. , Keller K. , Munz D. 
Published: December 2004

AbstractThe fracture toughness of three SiC‐materials was determined using specimens with straight‐through notches and Chevron notches as well as specimens with Knoop‐indentation cracks. The different procedures and results are compared and special effects such as crack‐healing and crack surface interactions are discussed.
Berechnung von Röntgenreflexen für polykristallines Titan unter dem Einfluß von Stickstoffgradienten und Eigenspannungen
Authors: Wieder T. , Herr W. , Gärtner H. 
Published: December 2004

AbstractIn der vorliegenden Arbeit wird ein Verfahren zur Berechnung von Röntgenreflexen eines Festkörpers, in dem gleichzeitig ein Konzentrationsgradient und ebene oberflächenparallele Eigenspannungen vorhanden sind, vorgestellt. Als Beispiel dient der (004)‐Reflex von nitriertem, eigenspannungsbehaftetem Titan. Die Profile und Lagen des (004)‐Reflexes werden berechnet für eine Eigenspannungsmessung nach dem ω‐Verfahren.Die erhaltenen Rechenergebnisse Zeigen, daß ein Konzentrationsgradient das Reflexprofil verbreitert, während homogene Eigenspannungen die Reflexlage verschieben. Die Reflexlage wird durch einen Konzentrationsgradienten in dem gewählten Stoffsystem nur vernachlässigbar beeinflußt, so daß eine Trennung beider Einflußgrößen aus der Diffraktogrammauswertung möglich ist.
Einfluß einer thermomechanischen Behandlung auf die mechanischen Eigenschaften der Ti6Al4V‐Legierung
Authors: Grundhoff Karl‐Josef , Schurmann Hartmurt 
Published: December 2004

AbstractInfluence of thermomechanical treatment on the mechanical properties of Ti6Al4VThermomechanical treatments of Ti6Al4V including deformation just below the β‐transus followed by water quenching and aging were shown to substantially improve the mechanical properties. Especially the fatigue strength was raised well beyond levels known from conventional processed material, for both room and elevated temperatures. The paper shows how other properties like tensile strength, ductility, fracture toughness, creep strength fatigue crack growth and stress corrosion cracking are affected.
Anwendung des Folge‐Wöhler‐Kurven‐Konzeptes zur Berechnung der Ausfallzyklenzahl bei unterschiedlichen Belastungsabläufen im niederzyklischen Ermüdungsgebiet
Authors: Schott G. 
Published: December 2004

AbstractDas Folge‐Wöhler‐Kurven‐Konzept konnte bislang mit Erfolg im Zeit‐ und Dauerschwingfestigkeitsgebiet bei spannungskontrollierten Blockprogramm‐ und Randombeanspruchungen eingesetzt werden. Im vorliegenden Beitrag wird untersucht, ob sich dieses Konzept im Gegensatz zu den örtlichen Konzepten, bei denen die Schädigungen linear summiert werden, für die Berechnung der Ausfallzyklenzahl bei dehnungskontrollierten unterschiedlichen Belastungsabläufen im LCF‐Gebiet eignet.Da das neue Konzept durch experimentell abgesicherte Ermüdungsfunktionen das reale Ermüdungsverhalten im Berechnungsablauf weitestgehend berücksichtigt, gelingt es, auch im LCF‐Bereich treffsichere Ausfallzyklenzahlen zu ermitteln.
Korrosionsschäden an Rührreaktoren mit Doppelmantel
Authors: Skiebe F. , Müller E. 
Published: December 2004

AbstractIm Rahmen von wiederkehrenden inneren Prüfungen an mit Außenkesseln versehenen Rührreaktoren, in denen Polymerisationen mit exothermer Reaktion stattfinden, erfolgten Ultraschallwanddickenmessungen an den Innenkesseln.
Lösung tribotechnischer Probleme mit Hilfe von Polymerwerkstoffen
Authors: Beringer H.‐P. , Heinke G. , Strickle E. 
Published: December 2004

AbstractDa das Reibungs‐ und Verschleißverhalten von Werkstoffen durch materialbezogene Kenngrößen nicht sicher charakterisiert werden kann, werden zur Werkstoffvorauswahl fü tribologisch beanspruchte Bauteile zumeist systemspezifische Kennwerte aus Modell‐Verschleißversuchen herangezogen. Model‐Verschleißversuche ermöglichen sowohl das Studium von Mechanismen der Tribologie, als auch die Charakterisierung der tribologischen Eigenschaften eines Werkstoffes. Die Standardisierung der Prüfbedingungen ermöglicht dabei einen Quervergleich unter den verschiedenen Polymerwerkstoffen.
Fertigungstechnische Beeinflussung der Erstarrungsvorgänge beim Hochtemperaturlöten unter Druckaufbringung
Authors: Steffens H.‐D. , Wielage B. , Dammer R. , Lebküchner‐Neugebauer J. 
Published: December 2004

AbstractBeim Erstarrungsverhalten von Hochtemperaturloten ist zu prüfen, inwieweit jenes durch eine Volumenzunahme der festen Phasen beeinflußt wird. Aufgrund thermodynamischer Gesetzmäßigkeiten kann durch eine Druckerhöhung das Wachstum von Phasen behindert werden, was zur Verbesserung des Lötverbundes beiträgt.
Effect of loading on the optimized shape of a kinked bar
Authors: Mattheck C. , Harzheim L. 
Published: December 2004

AbstractA kinked bar with two rectangular knees is shape optimized with respect to different single and one combined loading case. A guideline to shape optimization is given for combined loading. It was found that if the kinked bar is shape optimized with respect to the most unfavorable case of combined loading, the final optimum design will be also weight optimized. However if single load cases which are part of this combination or sub‐combinations are applied the design is still safe, but not weight‐minimized furthermore. The shape optimization was carried out with the CAO‐method (CAO: Computer Aided Optimization) which is based on a computer simulation of biological growth. It is a new method developed in the Karlsruhe Nuclear Research Center.
pH effect on the potentiodynamic behaviour of titanium electrodes
Authors: Khalil M. W. , Abdel Rahim M. A. 
Published: December 2004

AbstractPotentiodynamic measurements on mechanically polished titanium electrodes were performed in different solutions in the pH range 0.55–12. Two anodic peaks and one small cathodic peak were observed. Comparison with thermodynamic data revealed the possibility of formation of Ti2O3 or TiO2 at potentials corresponding to the first anodic peak probably directly from titanium hydride. The second anodic peak is interpreted as the oxidation of incorporated H to form H+ ions which partly remain inside the metal. The small cathodic peak represents the back reduction of the incorporated H+ to the metal hydride.
Einfluß verschiedener Wärmebehandlungsverfahren auf die Schwingfestigkeit von Sinterstählen
Authors: Sonsino C. M. 
Published: December 2004

AbstractDiese Untersuchung vergleicht das Schwingfestigkeitsverhalten der Sinterstähle Fe‐1,5%Cu, Fe‐1,5%Cu‐0.6%C und Fe‐0,8%Mn‐0,95%Cr‐0,24%Mo‐0,6%C in gesinterten und wärmebehandelten Zuständen. Die Legierung Fe‐1,5%Cu ist karbonitriert und die beiden anderen vergütet. Da in der Praxis Bauteile Spannungskonzentrationen aufweisen und unterschiedlichen Belastungsarten ausgesetzt sind, wurden die Versuche mit ungekerbten und gekerbten Proben unter Axial‐ und Biegebelastung mit unterschiedlichen Mittelspannungen durchgeführt. Die Auswahl dieser Werkstoffe, der Wärmebehandlungsbedingungen. Probengeometrien und Belastungsarten deckt ein breites Anwendungsfeld ab.
Chemische Diffusion von Molybdän in hochlegierten austenitischen CrNiMo(N)‐Stählen
Authors: Kühl A. , Bergner D. 
Published: December 2004

AbstractMit Hilfe der Sandwichmethode wurde die Volumendiffusion von Mo in austenitischen CrNiMo(N)‐Stählen untersucht. Danach können für die gegebenen Stahlzusammensetzungen mit 12–19 Ma% Cr, 12–16 Ma% Ni, 0–2 Ma% Mo und 0–0.27 Ma% N(Rest Fe) die chemischen Diffusionskoeffizienten (DK) des Mo im Temperaturbereich von 1283 bis 1523 K als konzentrationsunabhängig betrachtet werden. Die Diffusion von Mo in diesen Stählen läuft schneller ab als die Volumendiffusion von Cr, Ni und Fe. Die Mo‐Diffusionsparameter werden durch eine Zulegierung von etwa 0,25 Maß N verringert; möglicherweise als Folge des durch den N verursachten Gitteraufweitungseffektes bzw. erhöhter Leerstellenkonzentration durch N. Unterschiede in den Ausgangskonzentrationen von Cr und Ni haben keinen signifikanten Einfluß auf die Absolutwerte der chemischen DK des Mo.
Analyse und Modellierung des Kriechverhaltens von Kunststoffen und Metall‐Klebverbindungen
Authors: Dorn L. , Salem N. 
Published: December 2004

AbstractEmpirische Ansätze und rheologische Modelle dienen zur Ermittlung von Werkstoffkennwerten aus einachsig beanspruchten Proben, die als Eingangsgrößen für die numerischen FEM‐Berechnungen erforderlich sind. Dafür wurde der Potenzansatz nach Nutting zugrunde gelegt, wobei die Ansatzparameter mittels der Methode der kleinsten Fehlerquadratsumme und der graphischer Anpassung sowie einer Kombination der beiden Lösungswegen ermittelt werden. Mit den berechneten Parameterwerten werden die Dehnungen des Kunststoffs sowie die Gleitungen der Epoxidklebschicht ermittelt. Der Vergleich der Ergebnisse zeigt unterschiedliche Approximationsgüten zu den experimentellen Werten auf.
Open circuit potential for Copper Electrode in 1 M NaCl solutions
Authors: Abdulhay Malik A. , Al‐Suhybani Abdulaziz A. 
Published: December 2004

AbstractThe open circuit potential (OCP) of Cu electrode in 1 M NaCl solution was studied under different conditions. These include the change in pH (1–13), temperature (10–50°C) and the effect of O2, N2 and two organic additves, namely Sodium Methyl Dithiocarbamate and Sodium Butyl Dithiocarbamate. It was found that OCP changes to the positive or negative directions, depending on pH. The effect of temperature was found to depend mainly on pH. The presence of O2 has a pronounced effect on the potential and so is the addition of the two organic additives. The change of potential seems to be complicated since the kinetics of the change was found to be first, second or mixed first and second‐order depending on pH. The solid products formed at the electrode surface (pH = 1–9) were identified by IR spectroscopy.
Rißfortschrittsverhalten festgewalzter Kerbproben unter Axialbelastung
Authors: Kloos K. H. , Kaiser B. , Adelmann J. 
Published: December 2004

AbstractMit einer mechanischen Randschichtverfestigung durch Festwalzen können bei gekerbten Teilen beträchtliche Schwingfestigkeitssteigerungen erzielt werden, die hauptsächlich auf die günstige Wirkung der Randdruckeigenspannungen in der Rißfortschrittsphase zurückzuführen sind. An festgewalzten gekerbten Rundproben aus dem Vergütungsstahl 42 CrMo 4 wurde das Rißfortschrittsverhalten unter ein‐ und mehrstufiger Axialbelatung untersucht. Die Versuche ergaben einen ausgeprägten Einfluß von der Belastungshöhe und des Beanspruchungsverhältnisses auf den Eigenspannungszustand und die Rißentwicklung. Diese Zusammenhänge stehen im Einklang mit bruchmechanischen Modellvorstellungen, eine quantitative Vorhersage der Rißentwicklung erfordert jedoch weitergehende empirische Annahmen.
Electron transfer mediation characteristics of conducting Polymer Films of 4(5‐chloro‐2‐pyridyl)‐1,3‐diaminobenzene cobalt complex
Authors: El‐Rahman H. A. Abd , Rehan H. H. 
Published: December 2004

AbstractStable electroactive polymer films of cobalt complex of 4(5‐chloro‐2‐pyridylazo)‐1,3‐diaminobenzene (abbreviated as PCoL2) were prepared on glassy carbon electrodes by the oxidative polymerization of the complex in acetonitrile. Two pairs of reversible redox peaks for PCoL2 films were observed. The first pair is attributed to the electroactivity of the skeleton of the polymer and the other is attributed to the redox processes of the CO3+/2+ couple. The surface concentration of the electroactive Co sites was found to increase with increasing the film thickness. Mediation of reduction of [Fe(CN)6]3− by PCoL2 films was investigated by steady state measurements. The rate of the mediated reaction was found to be controlled by the rate of the charge propagation within the film & the rate of diffusion of the substrate through the film beside the rate of diffusion of the substrate to the electrode. Thin films were found to be potentially more efficient for the mediation than thicker films.
Effect of recycling on the mechanical properties of wood fiber–polystyrene composites. Part I: Chemithermomechanical pulp as a reinforcing filler
Authors: Maldas D. , Kokta B. V. 
Published: December 2004

AbstractThe feasibility for recycling composites of polystyrene‐hardwood aspen fiber (chemithermomechanical pulp or CTMP) was tested by evaluating the mechanical properties and dimensional stability of the original polymer and the recycled composites. The mechanical properties and dimensional stability of composites were investigated under extreme conditions (e.g., exposure to boiling water and at room temperature as well as exposure to +105°C and −20°C). The influence of coupling agent, e.g., 3% poly[methylene (polyphenyl isocyanate)] (PMPPIC), and various treatments, e.g., fiber coated with 10% polymer +8% PMPPIC and grafted with polystyrene 89.1% add‐on, on the properties of the composites have also been studied. Compared with the original composites, the mechanical properties and dimensional stability of the recycled composites did not change significantly even after exposure to extreme conditions. Moreover, the treated composites offered improved properties compared with nontreated and original polymer under all experimental conditions.
Dynamic mechanical measurements: Comparison between bending and torsion methods on a graphite‐reinforced and a rubber‐modified epoxy
Authors: Gerard J. F. , Andrews S. J. , Macosko C. W. 
Published: December 2004

AbstractDynamic mechanical measurements in the cantilever bending and torsion rectangular modes were compared on two epoxy samples: one unidirectionally reinforced by 42 vol.% graphite fibers, the other modified by 15 wt.% carboxy terminated acrylonitrile butadiene rubber. Two forced oscillation instruments were used: cantilever bending on a Polymer Labs DMTA and torsion with a Rheometrics System Four. In the cantilever mode, the storage modulus on both samples was measured at about two to three times too low because of compliance of the instrument. The two instruments agreed and appeared to measure accurately tan δ on the graphite‐reinforced samples. Agreement was only fair on tan δ for the rubber‐modified sample. Multiple frequency data were used to separate the glass‐transition temperature of the rubber from the epoxy β transition. Activation energies of these transitions are within the range reported. This study demonstrates the value of forced oscillation methods and the importance of selecting sample dimensions to fit instrument limits.
Ternary composites of polypropylene, elastomer, and filler: Analysis of phase structure formation
Authors: Pukánszky Béla , Tüdős F. , Kolařik Jan , Lednický František 
Published: December 2004

AbstractInvestigation of the morphology and properties of ternary composites of polypropylene, ethylene‐propylene‐diene terpolymer, and filler has shown that in such systems two kinds of structures can be formed: separate dispersion of the components or encapsulation of the filler by the elastomer. A thermodynamic analysis of the two structures revealed that encapsulation is the thermodynamically favored process. The final structure is determined by the stability of the encapsulated units, which depends on the relative magnitude of adhesion and shear forces. The former depends on the reversible work of adhesion and on the particle size of the filler, while the latter depends on the viscosity and shear rate. Surface treatment of the filler decreases the work of adhesion, resulting in extensive de‐encapsulation. The developed tentative explanation is in agreement with the observed phenomena and experimental results.
Silicon‐29 solid‐state nuclear magnetic resonance spectroscopy of composite interfaces
Authors: Hoh Ka‐Pi , Ishida Hatsuo , Koenig Jack L. 
Published: December 2004

AbstractThe types of structures and bonds that are formed with silicons in the composite interface were studied using 29Si cross‐polarization/magic angle sample spinning (CP/MAS) nuclear magnetic resonance spectroscopy (NMR). The change in mobility of silane coupling agent bonded to silica, as compared with bulk hydrolyzed silane coupling agent, can be monitored by the change in line width and the shift of resonances to higher fields, as well as by the change in the silicon‐proton cross‐polarization time TSiH. In the silane coupling agent‐matrix resin interface, the TSiH values reflect the change in mobility as a function of the concentration and degree of hydrolysis of the silane coupling agent. It has been demonstrated that quantitative measurements of TSiH can be used to investigate relative mobilities.
Extrusion blow molding of polyvinyl chloride homo‐ and copolymers
Authors: Taylor W. , King L. F. 
Published: December 2004

AbstractDynamic mill stability tests of PVC powder blends at the equiviscous temperatures were correlated with the clarity and color obtained in extrusion and blow molding of bottles. Copolymers of vinyl chloride with alkyl vinyl ether and propylene in a calcium‐zinc stabilizer, impact modified formulation had better processability than a homopolymer and produced bottles having lower values of absorbance and yellowness index. Product imperfections which were evident in blow molding of dry blends, but not during milling or capillary rheometer extrusion, were found to be related to the particle size distribution and volatile content of the resin.
Evaluation of biocides for treatment of polyvinyl chloride film
Authors: Kaplan A. M. , Greenberger M. , Wendt T. M. 
Published: December 2004

AbstractThe results of a study to determine the biological stability of clear, colorless, biocide‐treated PVC film are presented. With the exception of a resistant control, all the PVC film samples tested contained a plasticizer susceptible to biological deterioration. Biocide‐treated and control PVC film samples were subjected to biological attack in soil burial. Portions of each sample were exposed to leaching and to weathering in a weatherometer followed by soil burial to test the stability of each biocide to loss by water and weathering exposure. Of the 32 biocide preparations tested only 2, N‐(trichloromethylthio) phthalimide and copper 8‐quinolinolate, a known effective reference compound, were found to provide good protection for treated film in direct soil burial and in soil burial following leaching and weatherometer exposure. Natural weathering outdoors confirmed the results found with weatherometer exposed samples. The N‐(trichloromethylthio) phthalimide was less effective than the reference compound in suppressing surface growth. In addition, N‐(trichloromethylthio) phthalimide may not be compatible with all PVC formulations.
A new mthod for determining oven aging stability of polypropylene monofilament
Authors: Di Battista A. 
Published: December 2004

AbstractA precise method of oven‐aging polypropylene monofilament has been developed employing a tubular oven in which temperature and air velocity within each tube are accurately controlled. The monofilaments are suspended within each tube by means of specially construced heat stabilized polypropylene holders (no metal contact), which facilitate handling and record keeping. Each filament is held in an attitude perpendicular to the air flow. Failures almost invariably occur in the middle of each filament. Oxidative stabilities of filaments aged in the tubular oven at a constant temperature and air flow were found to be dependent upon (a) distance of the filaments from the incoming air side and (b) whether the exposure was continuous or intermittent. If these parameters are kept constant, relatively good precision can be obtained. The 95% confidence level for a single observed value was found to be on the order of ±10% of the average oven stability within the whole oven and ±7% within a single tube. Precisions of about ±2.5% can be obtained by employing averages of 10 replicates exposed on the same specimen holder.
Kinetics of thermally induced solid state polycondensation of poly(ethylene terephthalate)
Authors: Chang T. M. 
Published: December 2004

AbstractA diffusional model was established to study the kinetics of thermally‐induced solid state polycondensation of poly(ethylene terephthalate). Diffusion through solid polymer is the rate controlling step when temperature is higher than 210°C and particle size is no smaller than 100 mesh. The activation energy is 30 Kcal/g mole. In polymerizing powders (20‐200 mesh), the crystallinity of prepolymer and its changes during the polymerization affect the diffusivity and thus the polymerization rate. The diffusivity was found to be linearly proportional to the mass fraction of the amorphous phase in PET polymer.
Physico‐chemical characterization of poly(vinyl chloride). I. Solution properties
Authors: Baijal M. D. , Kauppila K. M. 
Published: December 2004

AbstractPoly(vinyl chloride) was fractionated and its solution properties were studied. Calibration of the gel permeation chromatograph was carried out using poly(vinyl chloride) and polystyrene. Empirical correlations were established for the calibration plots.
Viscoelastic stresses in a composite system
Authors: Hackett Robert M. 
Published: December 2004

AbstractA large number of composite materials are polyphase systems in which one phase exhibits time‐dependent properties. This paper presents an analysis of the stress redistribution in such a viscoelastic material system under the influence of applied external loads. In order to perform this study an appropriate idealized model, a series of which would tend to approximate the composition of a polyphase material, is formulated. The solution of the time‐dependent stress field is obtained by applying the “correspondence principle” to the elastic stress field solution which, for the selected model, has previously been obtained in numerical form.Application of the solution to a model of an actual polyphase composite material system yields results which clearly indicate that, under certain normally encountered conditions of external loading, the principal stresses in certain areas of such a system will increase significantly with time.
Mechanical properties of particulate composites
Authors: Sahu S. , Broutman L. J. 
Published: December 2004

AbstractThe mechanical properties of glass bead (30 micron diameter glass spheres) filled epoxy and polyester resins have been studied as a function of volume fraction of filler and the strength of the interfacial bond. The bonding between glass and resin was varied by chemically surface treating the glass using a silicone mold release to prevent chemical bonding at one extreme and a silane coupling agent to maximize bonding at the other extreme. Theoretical predictions of the elastic modulus and tensile strength have been made utilizing a finite element method. Excellent agreement is obtained with the experimental results. Izod impact energies have been measured for these composites as a function of filler content and interface treatment.
Determination of cure of diallyl phthalate using differential scanning calorimetry
Authors: Willard P. E. 
Published: December 2004

AbstractKinetic parameters (reaction rate constant, activation energy, and frequency factor) were determined by differential scanning calorimetry using a linearly rising temperature program for the polymerization of diallyl phthalate monomer catalyzed with dicumyl peroxide. Cure times for specific degrees of cure at constant temperature were calculated and found to agree with the degree of cure measured by infrared spectroscopy. The relationship between non‐isothermal and isothermal cure cycles is discussed.