bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bilirubin Removal from Human Plasma with Albumin Immobilised Magnetic Poly(2‐hydroxyethyl methacrylate) Beads
Authors: Rad Abbas Yousefi , Yavuz Handan , Kocakulak Mustafa , Denizli Adil 
Published: September 2003

AbstractBioaffinity separation has a unique and powerful role as a support tool in the removal of toxic substances from human plasma. Magnetic beads have advantages as supports in comparison to conventional nonmagnetic beads because of low pressure drop, high mass transfer rates, and good fluid‐solid contact. In addition, they eliminate internal diffusion limitations. Human serum albumin (HSA) immobilised onto magnetic poly(2‐hydroxyethyl methacrylate) (mPHEMA) beads were investigated as an adsorbent for the selective bilirubin removal from human plasma. The mPHEMA beads were prepared by a modified suspension polymerisation. HSA was covalently coupled to the mPHEMA beads. Bilirubin adsorption was investigated from hyperbilirubinemic human plasma on the mPHEMA beads containing different amounts of immobilised HSA, (between 11–100 mg/g). The nonspecific bilirubin adsorption on the unmodified mPHEMA beads was 0.47 mg/g. Higher bilirubin adsorption capacities, up to 64.7 mg/g, were obtained with the HSA‐immobilised magnetic beads. Bilirubin adsorption increased with increasing temperature.Effect of HSA loading on bilirubin adsorption.magnified imageEffect of HSA loading on bilirubin adsorption.
Structure of Escherichia coli dUTPase in Solution: A Small Angle Neutron Scattering Study
Authors: Vertesse Beata G. , Magazù Salvatore , Mangione Alfonso , Migliardo Federica , Brandt Astrid 
Published: September 2003

AbstractThe present study investigates shape properties of the enzyme dUTPase from Escherichia coli in the solution phase. In this work small angle neutron scattering (SANS) findings on dUTPase/D2O solutions for temperature values of T = 8 °C and T = 37 °C are presented. The analysis of SANS data, carried out by using a prolate ellipsoid core/shell model fitting and the well‐known Guinier and Zimm analysis procedures allows the characterization of the shape of the protein in solution. By means of the comparison with experimental and theoretical data existing in literature on dUTPase in the crystalline state, we find that the protein in solution maintains its dimensions before the denaturation process. Furthermore, by analyzing the SANS spectra of dUTPase/D2O/trehalose solutions, we emphasize the bioprotective effects of trehalose on the protein.Structure of dUTPase.magnified imageStructure of dUTPase.
Structural Characterization and Enzymatic Degradation of α‐, β‐, and γ‐Crystalline Forms for Poly(β‐propiolactone)
Authors: Furuhashi Yukiko , Iwata Tadahisa , Kimura Yoshiharu , Doi Yoshiharu 
Published: September 2003

AbstractA structural comparison of three different crystalline forms of poly(β‐propiolactone) (PPL) was carried out by wide‐angle X‐ray diffraction, Fourier‐transform infrared spectroscopy, and differential scanning calorimetry. The α‐form in a hot‐drawn and annealed film represents a 21 helix conformation. The β‐form in a cold‐drawn and annealed film represents a planar zigzag conformation. The γ‐form in an oriented sedimented mat of solution‐grown chain‐folded lamellar crystals also implies a planar zigzag conformation. The solution‐cast film depicts similar outlines with the γ‐form in lamellar crystals in all the experimental measurements, suggesting that the molecular chain in the solution‐cast film has a planar zigzag conformation. While elongation at break decreased, tensile strength and Young's modulus increased with an increase in the crystallinity, independent of the crystalline forms. The influence of the enzymatic degradation of these crystal structures has been investigated by using an extracellular PHB depolymerase purified from Ralstonia pickettii T1. The rate of degradation was in the order of β‐form > α‐form > solution‐cast (γ‐form) film, and the different surface morphologies after partial enzymatic degradation were observed in scanning electron micrographs. It is suggested that the crystal structure is one of the important factors for determining the rate of degradation together with crystallinity.Enzymatic degradation profiles of poly(β‐propiolactone) films.magnified imageEnzymatic degradation profiles of poly(β‐propiolactone) films.
The role of alloying elements in commercial alloys for corrosion resistance in oxidizing‐chloridizing atmospheres. Part II: Experimental investigations
Authors: Bender R. , Schütze M. 
Published: September 2003

AbstractIn an extensive study the role of the alloying elements in commercial alloys for corrosion resistance was studied in air without and with 0.1 and 2 vol.% Cl2, respectively. In the first part of this paper [1] the thermodynamic fundamentals were discussed on the basis of the new concept of the quasi‐stability diagrams. The second part which is presented here reports the results from investigations at 650, 800 and 1000°C and testing times up to 1000 hrs where 14 commercial alloys were tested with regard to their corrosion behavior. The materials were selected so that the role of the alloying elements Mo, C, Si, Al, N, Fe, Ni and Cr would be evident from the results. The exposure tests were followed by extensive microstructural analyses of the corrosion scales and the metal subsurface zones so that type, mechanism and extent of corrosion could be characterized in great detail. At the end a ranking was possible of the different materials and with regard to the detrimental or beneficial role of the different alloying elements. The present results thus provide a much deeper insight into materials resistance in oxidizing‐chloridizing environments at high temperatures.
Corrosion of carbon steel in filling material in an urban environment
Authors: Norin M. , Vinka T.‐G. 
Published: September 2003

AbstractThe corrosion process of carbon steel in soil has been investigated, in particular the influence of the soil of an urban environment. A field test was carried out with test panels buried in trenches. Localized and uniform corrosion rates were evaluated after 1 and 3 years. Soil samples from points adjacent to the panels were analyzed with respect to a number of physical and chemical parameters believed to influence the corrosion process. Corrosion products were analyzed and identified. The study shows that the localized corrosion rate of soil buried constructions may be remarkably high in a filling material in comparison to other soils. The heterogeneity of the soil seems to have a greater influence on the localized corrosion rate than the chemical composition of the soil. However, the uniform corrosion rate was comparatively low in the heterogeneous filling material. Both the high alkalinity in the soil water and the groundwater, and the high total hardness of the soil water in the filling material seem to reduce the uniform corrosion rate. Corrosion rate determinations with commercial probes is also discussed. The linear polarization resistance (LPR), the electric resistance (ER) and the corrosion potential measurement techniques are compared. All probes showed a seasonal variation in corrosion rate. The measurements with commercial probes were associated with some problems, mostly a result of poor contact between the probes and the soil.
The hot corrosion behaviour of HVOF sprayed MCrAlX coatings under Na2SO4 (+NaCl) salt films
Authors: Pahlavanyali S. , Sabour A. , Hirbod M. 
Published: September 2003

AbstractThe hot corrosion behaviour of two NiCoCrAlYTa and CoCrAlYSi HVOF sprayed coatings and a CoCrAlY VPS coating were investigated under laboratory conditions at 900°C using a synthetic gas atmosphere containing sulphur as an impurity. All the coatings tested showed good protection under Na2SO4 salt films. In the presence of NaCl in the Na2SO4 salt films, the corrosion rates of low Al containing coatings increased considerably but the NiCoCrAlYTa coating with higher Al content still revealed good performance. It is suggested that NaCl in the salt film causes premature failure of the protective scale and reduces the incubation period of corrosion in the coatings of lower Al content. Furthermore, it seems that the finely dispersed Al rich oxide particles in the sprayed and heat‐treated HVOF coating microstructure do not lead to internal corrosion. The experimental investigations include short‐term corrosion kinetic measurements and SEM analyses.
An in‐situ FT‐IR investigation of the anodic behaviour of WC‐Co hardmetal
Authors: Bozzini B. , De Gaudenzi G. P. , Mele C. 
Published: September 2003

AbstractAn in‐situ FT‐IR spectroelectrochemical and voltammetric study of the corrosion of a WC‐Co hardmetal grade is reported in this communication. A slightly acidic sulphate solution is considered. The potential‐ and time‐dependent anodic formation of CO2 and Co(OH)2 can be followed with the variation of the vibrational spectra. The formation of CO2 occurs at the same potential at which tungsten oxidation starts to be detected and the breakdown of passivity can be observed by electrochemical methods. Our results suggest that a threshold potential exists for the oxidation of WC in WC‐Co, giving rise to the concomitant oxidation of tungsten and carbon at more noble potentials than those typical for the oxidation of the individual elements.
Study on corrosion of steels in marine environment by corrosion simulation device
Authors: Xiang B. , Zhang J. , Duan J. Z. , Hou B. R. 
Published: September 2003

AbstractThree kinds of steels were studied using electrically connected hanging specimen in the corrosion simulation device and offshore long scale hanging specimen. The experimental results obtained by the two methods show that the device can better reflect the offshore corrosion environment. A Ni‐Cu‐P steel specimen was studied through analysis of the specimen's corrosion products and corrosion types. The surface of the samples before and after the removal of the rust layer produced by these two methods were observed and compared after some experiments. The microstructure of the corrosion products under different marine environments were analyzed and compared through IR. It indicated good correlation between the electrically connected hanging specimen method and the long scale hanging specimen method.
Biodegradable Polylactide and Its Nanocomposites: Opening a New Dimension for Plastics and Composites
Authors: Ray Suprakas Sinha , Okamoto Masami 
Published: September 2003

AbstractThe academic and industrial aspects of the preparation, characterization, mechanical and materials properties, crystallization behavior, melt rheology, and foam processing of pure polylactide (PLA) and PLA/layered silicate nanocomposites are described in this feature article. Recently, these materials have attracted considerable interest in polymer science research. PLA is linear aliphatic thermoplastic polyester and is made from agricultural products. Hectorite and montmorillonite are among the most commonly used smectite‐type layered silicates for the preparation of nanocomposites. Smectites are a valuable mineral class for industrial applications because of their high cation exchange capacities, surface area, surface reactivity, adsorptive properties, and, in the case of hectorite, high viscosity, and transparency in solution. In their pristine form, they are hydrophilic in nature, and this property makes them very difficult to disperse into a polymer matrix. The most common way to overcome this difficulty is to replace interlayer cations with quaternized ammonium or phosphonium cations, preferably with long alkyl chains. In general, polymer/layered silicate nanocomposites are of three different types: (1) intercalated nanocomposites, in which insertion of polymer chains into the layered silicate structure occurs in a crystallographically regular fashion, regardless of polymer to layered silicate ratio, with a repeat distance of few nanometer; (2) flocculated nanocomposites, in which intercalated and stacked silicate layers are sometimes flocculated due to the hydroxylated edge–edge interactions between the silicate layers; (3) exfoliated nanocomposites, in which individual silicate layers are uniformly distributed in the polymer matrix by average distances that totally depend on the layered silicate loading. This new family of composite materials frequently exhibits remarkable improvements in its material properties when compared with those of virgin PLA. Improved properties can include a high storage modulus both in the solid and melt states, increased flexural properties, a decrease in gas permeability, increased heat distortion temperature, an increase in the rate of biodegradability of pure PLA, and so forth.Illustration of the biodegradability of PLA and various nanocomposites.magnified imageIllustration of the biodegradability of PLA and various nanocomposites.
Novel Chromophore‐Functionalized Poly[2‐(trifluoromethyl) adamantyl acrylate‐methyl vinyl urethane]s with High Poling Stabilities of the Nonlinear Optical Effect
Authors: Briers David , Koeckelberghs Guy , Picard Isabel , Verbiest Thierry , Persoons André , Samyn Celest 
Published: September 2003

AbstractNonlinear optical vinyl polymers with high glass transition temperature (Tg) were prepared by the functionalization of a fluorinated acrylate‐methyl vinyl isocyanate copolymer. A modified pathway to obtain a thiophene bridged chromophore was worked out. Poled films of the polymers show a fairly high and stable nonlinear optical response, even at elevated temperatures.The thiophene‐bridged chromophore, based on a substituted dicyanomethylene‐dihydrofuran acceptor, synthesized here.magnified imageThe thiophene‐bridged chromophore, based on a substituted dicyanomethylene‐dihydrofuran acceptor, synthesized here.
Chiral Biomineralization: Mirror‐Imaged Helical Growth of Calcite with Chiral Phosphoserine Copolypeptides
Authors: Sugawara Tetsunori , Suwa Yukie , Ohkawa Kousaku , Yamamoto Hiroyuki 
Published: September 2003

AbstractTheO‐phospho‐L‐serine [Ser(P)] containing peptides and proteins play an important role in controlling the morphology of biominerals. The poly[Ser(P)] and copoly[Ser(P)xAspy] affect the calcium carbonate (CaCO3) morphology and polymorph. The CaCO3helical structures were obtained in the presence of copoly[Ser(P)75Asp25]. When theL‐copolymer was used as an additive, a clockwise P twisted spiral morphology was formed. On the other hand, when usingD‐copolymer, a counterclockwise M twisted spiral morphology was obtained.Optical micrographs of chiral morphologies of CaCO3in the presence of a)L‐copolymer and b)D‐copolymer.magnified imageOptical micrographs of chiral morphologies of CaCO3in the presence of a)L‐copolymer and b)D‐copolymer.
Characterization of Defined Metal‐Containing Supramolecular Block Copolymers
Authors: Meier Michael A. R. , Lohmeijer Bas G. G. , Schubert Ulrich S. 
Published: September 2003

AbstractThe characterization of metal‐containing supramolecular polymers by gel permeation chromatography (GPC) or matrix‐assisted laser desorption ionisation time‐of‐flight mass spectrometry (MALDI‐TOF MS) is complicated because of the interaction of the charged materials with the GPC column material in the first case and fragmentation due to the applied laser energy in the latter case. In this contribution we report recent advances made for the characterization of supramolecular polymers based on terpyridine metal complexes utilizing GPC and MALDI‐TOF MS. In particular for GPC analysis, the choice of solvent and additive was found to be crucial for a successful characterization. Furthermore, MALDI‐TOF MS spectra of these compounds are not straightforward to interpret. Both aspects are discussed in detail with the result of a better understanding and improved analysis possibilities of the mentioned supramolecular polymers.A GPC‐coupled in‐line diode array spectrum of one of the complexes investigated here.magnified imageA GPC‐coupled in‐line diode array spectrum of one of the complexes investigated here.
Betriebsfestigkeit und Zuverlässigkeit von komplexen und intelligenten Strukturen
Authors: Hanselka H. , Sonsino C. M. 
Published: September 2003

AbstractDie Betriebsfestigkeit und Zuverlässigkeit einer Konstruktion ist nur durch sorgfältige Bemessung zu erreichen. Dabei sind die aus den Einsatzprofilen stammenden unterschiedlichen Anforderungen an die Festigkeit der Bauteile zu berücksichtigen. Um einerseits alle Einflüsse aus Belastung, Werkstoff, Herstellungsprozess, örtlicher Geometrie zu erfassen und andererseits Forderungen bezüglich der Konkurrenzfähigkeit zu erfüllen, muss der Konstrukteur effiziente Methoden anwenden, mit denen Betriebsfestigkeit und Zuverlässigkeit gewährleistet werden.Heute steht im Entwicklungsprozess einer Konstruktion die Verringerung der Markteinführungszeit im Vordergrund. Dies erfordert den vermehrten Einsatz numerischer Methoden (Simulation des dynamischen Systemverhaltens, der Bauteileigenschaften und der örtlichen Spannungen), um den Aufwand der experimentellen Vorgehensweise für Optimierung und Nachweis zu reduzieren.In Zukunft werden immer mehr Konstruktionsteile von mechatronischen und sogar multifunktionalen Komponenten ersetzt. Kenntnisse des Systemverhaltens sowie der gegenseitigen Beeinflussung von elektronischer Steuerung und mechanischem Verhalten sind erforderlich, um die Zuverlässigkeit dieser Entwicklung zu bewerten.
Effects of Loading Waveform and Stress Field on High Temperature Fatigue Crack Growth of Alloy 718
Authors: Heuler P. , Affeldt E. , Wanhill R.J.H. 
Published: September 2003

AbstractHigh temperature fatigue in nickel‐base superalloys for aero‐engine applications requires consideration of cycle‐ and time‐dependent phenomena. For waveforms with dwells and/or low frequencies crack growth rates may be significantly accelerated up to the point of fully time‐dependent crack growth. In the paper, the interaction of fatigue (cycle‐dependent) and dwell (time‐dependent) crack growth is addressed using a broad database for IN 718 tested at 600°C. Waveforms with dwells at as well as below maximum load levels are applied to standard CT and CC specimens and blunt notched specimens. It is demonstrated that both the level of dwells with respect to the maximum load level within a cycle as well as the specific conditions at the notch root considerably affect the significance of dwells for fatigue crack growth.
Betriebsfestigkeit und Äquivalentamplitude
Authors: Hänel B. 
Published: September 2003

AbstractDer Betriebsfestigkeitsnachweis ist im Allgemeinen mit einem Spannungskollektiv durchzuführen. Bei Anwendung von Normkollektiven, Beanspruchungsgruppen oder Äquivalentamplituden ergeben sich Vereinfachungen, besonders im letzten Fall: Der Betriebsfestigkeitsnachweis hat dann die äußere Form eines Dauerfestigkeitsnachweises.Rechnerisch ist das immer möglich, experimentell aber nur mit Einschränkungen.
Lebensdauervorhersage auf Basis von Finite Elemente Ergebnissen
Authors: Eichlseder W. 
Published: September 2003

AbstractUnter dem Druck des Wettbewerbes werden möglichst kurze Produktentwicklungszeiten angestrebt, weshalb bereits im frühen Entwicklungsstadium Aussagen über die Lebensdauer und damit die Dimensionierung der Bauteile erforderlich werden. Da durch die häufig angestrebte Gewichtsoptimierung der Bauteile das Limit der Belastbarkeit so nah wie möglich erreicht werden soll, werden Simulationsmethoden sowohl im Berechnungs‐ als auch im Versuchsablauf verstärkt eingesetzt. Ausgehend von den Berechnungsergebnissen nach der Finte Elemente Methode werden zur Lebensdauervorhersage von Bauteilen örtliche Wöhlerlinien benötigt, die häufig aus Wöhlerlinien, ermittelt an Proben unter Laborbedingungen, abgeleitet werden müssen. Diese Übertragbarkeit von Proben‐ auf Bauteilwöhlerlinien wird für die Einflüsse durch Kerben, Größe und Gussgefüge exemplarisch aufgezeigt. Aufbauend auf diesen Wöhlerlinien, die für jede Stelle im Bauteil errechnet werden, kann unter Einbeziehung der lokalen Spannungen und Spannungsgradienten, ermittelt mit der Finite Elemente Methode, die Lebensdauer errechnet werden.
Prüftechnische Innovationen – Grundlage für Erfindungen in der Bauteilentwicklung
Authors: Hug J. , Runzer V. 
Published: September 2003

AbstractIn Clausthal‐Zellerfeld wurde bereits 1828 mit der ersten dynamischen Prüfmaschine der Welt der Grundstein für die Betriebsfestigkeit gelegt. Heute ist an dieser Stelle ein Kompetenzzentrum für Betriebsfestigkeit und dynamische Prüftechnik entstanden. Die Entwicklung neuer Prüfmaschinen und Prüfverfahren führt sehr oft zu Innovationen der zu prüfenden Bauteile und Systeme. Dies wird zunächst an Julius Albert's Kettenprüfmaschine, dann an aktuellen herausragenden Beispielen der Resonanzprüftechnik, wie dem Power Swing, dem Hochdruckprüfsystem bis 4000 bar und der Umlaufbiegeprüfsysteme der SincoTec GmbH veranschaulicht.
Datensammlung Betriebsfestigkeit – Zuverlässigkeit von Lebensdauerabschätzungen
Authors: Kotte K.L. , Eulitz K.‐G. 
Published: September 2003

AbstractNach der Wiedervereinigung Deutschlands initiierte Prof. Harald Zenner mehrere Forschungsvorhaben, die das Ziel verfolgten, das gesamtdeutsche Know‐How der Betriebsfestigkeit und den existierenden Fundus an Versuchsergebnissen aufzuarbeiten und damit für die weitere Nutzung zu sichern. In diesem Zusammenhang bearbeiteten das IMAB der TU Clausthal und das IFKM der TU Dresden gemeinsam zwei Vorhaben “Lebensdauervorhersage I und II”, die ihr Ergebnis zum einen in der Datensammlung Betriebsfestigkeit “DABEF”, zum anderen in einer sauberen statistischen Analyse zur Treffsicherheit der Lebensdauerabschätzungsverfahren hatten. Im Ergebnis dieser Untersuchungen wurden die Einflüsse des Klassierverfahrens von denen der Schadensakkumulation getrennt. Für die unterschiedlichen Berechnungsgruppen und Varianten der Miner‐Rechnung war es möglich, Anpassungsfaktoren für berechnete zulässige Beanspruchungen anzugeben. Die Datensammlung wurde inzwischen als wesentliche Basis für eine Habilitation sowie für mehrere Dissertationen und andere Forschungsarbeiten genutzt. Nicht zuletzt fanden die Ergebnisse der statistischen Analysen Eingang in die Richtlinie für den “Rechnerischen Festigkeitsnachweis” des FKM.
Betriebsfestigkeit + Funktion = Betriebsfunktionalität, Anforderungen an die Entwicklung von Fahrwerkbauteilen
Authors: Jung L. , Saathoff A. , Witt M. 
Published: September 2003

AbstractDie Betriebsfestigkeit hat innerhalb der Fahrwerkentwicklung einen sehr hohen Stellenwert, da Fahrwerkbauteile in der Regel Sicherheitsbauteile sind. Die Festigkeit stellt jedoch nur einen Teilaspekt innerhalb der Entwicklungstätigkeit dar. Die übergeordnete Aufgabe in der Bauteilentwicklung ist die Sicherstellung der Funktionalität unter allen Betriebsbedingungen. Für die Bauteile Radlager, Gelenkwelle und Stabilisator werden beispielhaft die Entwicklungsanforderungen diskutiert.
Betriebsfestigkeit in der Fahrzeugentwicklung – von der Theorie zum Produkt
Authors: Jung T. , Liu J. , Maescher G. , Mauch H. , Stolze F.‐J. 
Published: September 2003

AbstractDargestellt wird die prinzipielle Vorgehensweise beim Nachweis der Betriebsfestigkeit in der Fahrzeugentwicklung: die Methoden, Lastannahme, Festigkeitsprüfung und die Vorschriften für die Freigabe und Qualitätssicherung. An praktischen Beispielen der Fahrzeugentwicklung aus Fahrwerk, Aggregat und Karosserie werden die Vorgehensweise und die verwendeten experimentellen und rechnerischen Simulationsmethoden erläutert.