bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spannung‐Dehnung‐Hysteresismessungen an zyklisch beanspruchtem unidirektional SiC‐kurzfaserverstärktem Alkali‐Kalk‐Silicatglas
Authors: Marchetti K. , Roeder E. , Eifler D. 
Published: May 2005

AbstractIm Hinblick auf die technische Anwendung faserverstärkter Gläser ist die Kenntnis des Ermüdungsverhaltens dieser Werkstoffe eine unabdingbare Voraussetzung. Hierzu wurden AR‐Glasproben sowie SiC‐kurzfaserverstärkte AR‐Glas‐Verbundproben durch Strangpressen hergestellt und in spannungskontrollierten 3‐Punkt‐Biegeversuchen im Schwellbereich schwingend beansprucht. Die Charakterisierung des zyklischen Verformungsverhaltens und die Bewertung der Versagensmechanismen in Abhängigkeit von Beanspruchungsamplitude, Beanspruchungsdauer und Faservolumengehalt erfolgte mit Hilfe des Hysteresismeßverfahrens sowie lichtmikroskopischer Strukturuntersuchungen an den Probenoberflächen. Ausgewählte Versuchsergebnisse werden vorgestellt und diskutiert.
Anrißlebensdauervorhersagemethode für beliebige mehrachsige Beanspruchungen mit kontinuierlicher Schädigungserfassung
Authors: Ott W. , Nowack H. , Trautmann K.‐H. 
Published: May 2005

AbstractDas Problem der Anrißlebensdauervorhersage bei beliebigen proportionalen und nicht‐proportionalen mehrachsigen Schwingbeanspruchungen im Zeitfestigkeitsbereich ist immer noch nicht befriedigend gelöst. In der vorliegenden Arbeit wird eine neue Methode vorgeschlagen, mit der an hochfesten mittelspannungsempfindlichen Aluminiumlegierungen positive Ergebnisse erzielt wurden. Diese Methode benutzt die plastische Arbeit, die in jedem Punkt eines mittels der elastisch‐plastischen FE‐Methode dargestellten Prüfkörpers während der mehrachsigen schwingbelastunginkrementell akkumuliert wird, als Indikator für die auftretende Ermüdungsschädigung. Eine neue Formulierung berücksichtigt zusätzlich die momentane Mittelspannungen. Aus Anwendersicht ist die vorgeschlagene Methode vorteilhaft, weil besondere ermüdungsbezogene Beanspruchungsereignisse, wie z. B. geschlossene Hystereseschleifen, nicht definiert und „gezählt”︁ werden müssen.
Bewertung des Einflusses von Eigen‐ und Mittelspannungen auf die Dauerfestigkeit des Stahls 42CrMo4 im vergüteten Zustand
Authors: Bomas H. , Linkewitz T. , Mayr P. 
Published: May 2005

AbstractSeit langem ist die qualitative Wirkung von Mittel‐ und Eigenspannungen auf die Dauerfestigkeit von Stählen bekannt. Die quantitative Beschreibung der Wirkung der Eigenspannungen erscheint jedoch unzureichend, da die Besonderheiten des Eigenspannungszustandes wie Nichtstabilität während der Belastung, Mehrachsigkeit, starke Gradienten sowie gelegentliche große Unterschiede zwischen Oberfläche und Volumen in den gängigen Konzepten nicht berücksichtigt werden. Es werden Untersuchungen zur Dauerfestigkeit eines vergüteten Stahls vorgestellt, auf die verschiedene Konzepte zur Bewertung von Eigen‐ und Mittelspannungen angewandt werden. Hierbei zeigt sich, daß auf die Unterscheidung zwischen Eigenspannungs‐ und Mittelspannungsempfindlichkeit verzichtet werden kann, wenn das Bewertungskonzept die oben genannten Charakteristika der Eigenspannungen berücksichtigt.
Gefüge und Korrosionsverhalten eines stickstofflegierten rostfreien Stahls
Authors: Herzbach L. C. , Schmidt H. , Windler M. 
Published: May 2005

AbstractDas Korrosionsverhalten eines stickstofflegierten rostfreien Stahles wird durch potentiodynamische anodische Polarisation in physiologischer NaCl‐Lösung untersucht. Der Gefügezustand geschmiedeter Proben wird mikroskopisch und durch Härtemessungen ermittelt. Der Stahl weist ein globulares austenitisches Gefüge auf, in der Zone starker Schmiedeverformung sind die Körner gestreckt. Es liegen Ausscheidungen vor, in denen Chrom und Molybdän angereichert sind. Der Stahl zeigt Durchbruchspotentiale zwischen 200 und 1170 mV vs. SCE, die meisten Werte liegen über 500 mV. Die Durchbruchspotentiale fallen mit zunehmendem Streckungsgrad der Körner und zunehmender Härte ab. Die Ausscheidungen sind Initialpunkte für loch‐ und kraterförmigen Materialabtrag.
Corrosion Inhibition of mild steel in aqueous solution containing H2S by some naturally occurring substances
Authors: Barakat Y. F. , Hassan A. M. , Baraka A. M. 
Published: May 2005

AbstractThe corrosion inhibition of mild steel by some naturally occuring substance was evaluated in absence and presence of 600 and 1200 mg H2S/l in 3% NaCl aqueous solution and pH of 3 and temperature of 25 °C. These naturally occurring substance included the water extracts, coumarines and fatty matters extracts of some Egyptian plants. These plants included:(1) Nigella Sativa (Family Ranunculacease) (Extract (1), 2) Coriandrum Sativum (Family Umbelliferea) (Extract II), 3) Ricinus communis (Family Euphorbiaceae) (Extract III). The galvanostatic anodic and cathodic polarization measurements were used for studying the corrosion behavior of mild steel and evaluation of the percentage inhibition of the undertesting extracts of these three plants and also preparation of fatty matters and coumarin fractions were mentioned.
Entwicklung metallorganisch basierter Keramiken
Authors: Gadow R. , Kienzle A. 
Published: May 2005

AbstractAusgangspunkt des Polymer‐Pyrolyse‐Verfahrens stellen hochreine monomere Precursor dar, die über Additions‐ oder Kondensationsreaktionen polymerisiert und durch Pyrolyse unter Schutzgasatmosphäre in amorphe Keramiken überführt werden. Durch Tempern bei erhöhter Temperatur können die Keramiken zur Kristallisation gebracht werden. Die Pyrolyse von Polysilanen und Polycarbosilanen ergibt Si‐C‐Keramiken, Polysiloxane werden in Si‐C‐O‐Keramiken und Polysilazane bzw. Polysilylcarbodiimide in Si‐C‐N‐ oder Si3N4‐Keramiken umgewandelt. Durch Kombination verschiedener Precursormaterialien lassen sich über die Polymer‐Pyrolyse‐Route Multikomponentenkeramiken außerordentlicher Homogenität und mit vielfältigen Eigenschaften herstellen. Die erreichbaren keramischen Ausbeuten liegen je nach Precursorsystem bei bis zu 90%. Die beschriebenen Keramiken finden Anwendungen in Form monolithischer Formkörper, als Fasern oder faserverstärkte Verbundwerkstoffe oder als über Dip‐Coating hergestellte Schichten.
Anforderungen und Bewertung dünner Schichten im tribologischen Einsatz
Authors: Friedrich C. , Berg G. , Senf J. , Broszeit E. , Kioos K.‐H. 
Published: May 2005

AbstractDünne Schichten für die Tribologie sind in den letzten Jahren und Jahrzehnten intensiv gefördert worden. Dementsprechend viele Einzelkenntnisse liegen daher zu diesem Thema vor. Bis heute fehlt jedoch eine handhabbare und zuverlässige Entwicklungssystematik für den praktischen Ingenieureinsatz. Die am Schluß des Beitrags angegebene Literaturquelle greift dieses Problem auf und zeigt Lösungen. Nachfolgender Beitrag stellt einen Ausschnitt daraus vor. Aus diesem Grund werden einzelne Aspekte nur beschrieben, ohne alle Einzelheiten an dieser Stelle zu belegen. Dafür steht die Quelle mit vielen detaillierten Hinweisen zur Anwendung von Hartstoffschichten und über 900 weiteren Literaturverweisen zum Thema zur Verfügung. Dort finden sich auch alle hier fehlenden Angaben zu einzelnen Parametern und Randbedingungen sowie weitere Daten und Angaben zu allen hier angesprochenen Aspekten. Auswahl‐ und Bewertungstabellen machen die Quelle zu einem nützlichen Handbuch für den Einsatz von dünnen Hartstoffschichten in Theorie und Praxis. Bei Fragen zur Beschaffung der Literaturquelle steht der Autor für nähere Auskünfte zur Verfügung.
Wälzverschleiß und ‐ermüdung von Bauteilen und Maßnahmen zu ihrer Einschränkung
Authors: Böhmer H.‐J. 
Published: May 2005

AbstractWälzbeanspruchte Teile, wie Zahnräder und Wälzlager, unterliegen ganz charakteristischen Beanspruchungen, wie sie in anderen technischen Anwendungen nicht vorkommen. Diese besonderen Bedingungen und ihre Auswirkungen auf die Beanspruchungsverhältnisse und das Werkstoffverhalten werden ausführlich beschrieben. Vor allem Ingenieuren, die weniger mit dem Themenkomplex Wälzermüdung und ‐verschleiß vertraut sind, soll eine übersichtliche und gestraffte Einführung in dieses Gebiet gegeben werden. Hierzu werden die wichtigsten Einflußgrößen auf das verhalten wälzbeanspruchter Bauteile, der Ablauf einer eventuellen Schadensinitiierung und die Erscheinungsbilder verschiedener Ausfallsursachen dargestellt. An Beispielen wird gezeigt, wie sich aus der Analyse der Schädigungsabläufe Abhilfemaßnahmen herleiten lassen. Die Literaturhinweise sind so gewählt, daß sich der interessierte Leser in die einzelnen Themengebiete selbständig weiter vertiefen kann.
Supercritical fluid extraction combined with microcolumn liquid chromatography for the analysis of polymer additives
Authors: Hirata Y. , Okamoto Y. 
Published: May 2005

AbstractPolymer additives were extracted with supercritical carbon dioxide and collected in a microtrap. The collected samples were separated by microcolumn liquid chromatography. Polymer samples down to the sub‐milligram level were handled without loss of extract. Information about the distribution of additives was also obtained.
Capillary zone electrophoresis with laser fluorescence detection of marine toxins
Authors: Wright Bob W. , Ross Gerald A. , Smith Richard D. 
Published: May 2005

AbstractCapillary zone electrophoresis (CZE) was applied to the characterization of highly polar marine toxins that can be difficult to address using traditional chromatographic methods. Separation efficiencies of nearly 400,000 the oretical plates were obtained in just over 10 min. Laser fluorescence detection provided attomole detection limits of parts per trillion solutions.
Scanning ultraviolet detection in capillary supercritical fluid chromatography
Authors: Weinberger Scot R. , Bornhop Danyl J. 
Published: May 2005

AbstractA rapid‐scanning ultraviolet‐visible (UV‐vis) detector was interfaced successfully with capillary supercritical fluid chromatography (SFC). The pseudo on‐column detection approach was used to produce a detector dead volume of less than 60 nL. High sensitivity (low picogram detection limits), a large linear dynamic range (greater than three orders of magnitude in concentration), and full spectral scanning were achieved. Many of the limitations commonly encountered when in corporating a photodiode array (PDA) into a capillary‐based separation scheme were overcome. An SFC separation of several pesticides and caffeine illustrate the utility of the detector‐SFC system.
Microcolumn supercritical fluid chromatography with on‐line Fourier transform infrared detection
Authors: Raynor Mark W. , Clifford Anthony A. , Bartle Keith D. , Reyner Colin , Williams Alan , Cook Bernard W. 
Published: May 2005

AbstractThe combination of capillary supercritical fluid chromatography (SFC) and Fourier transform infrared spectrometry (FTIR) is demonstrated using a low‐volume (0.8 μL) flow cell capable of withstanding high pressures. The design of the interface is presented, and its effect on peak shape and detector sensitivity is discussed. In order to optimize the system for use with 50‐μ i.d. capillary columns, makeup fluid is added to the column effluent before it passes through the flow cell to a flame ionization detector (FID). Loss in chromatographic resolution caused by the cell's dead volume is therefore minimized, which is clearly demonstrated by the analysis of two ultraviolet curing coatings using carbon dioxide as a mobile phase. This application highlights the analytical power of the system for separating and identifying reactive monomers, oligomers, and photoinitiators in low‐ to medium‐molecular‐weight polymer systems.
Effects of pH on electrokinetic velocities in micellar electrokinetic chromatography
Authors: Otsuka Koji , Terabe Shigeru 
Published: May 2005

AbstractEffects of pH of micellar solutions on electrokinetic velocities in micellar electrokinetic chromatography were investigated using sodium dodecyl sulfate (SDS) solutions. The electroosmotic velocity decreased with a decrease in pH below 5.5, while the electrophoretic velocity of the SDS micelle was almost constant throughout the pH range of 7.0–3.0. Consequently, the migration velocity of the SDS micelle decreased with a decrease in pH, and its direction changed at pH 5.0: the direction was the same as that of the electroosmotic velocity above pH 5.0 and the reverse below pH 5.0. In the latter case, the retention time and resolution will be infinity at a relevant value of the capacity factor, and a wider elution range can be attained.
Resolution of optical isomers by capillary zone electrophoresis: Study of enantiomeric and diastereoisomeric Co(III) complexes with ethylenediamine and amino acid ligands
Authors: Fanali S. , Ossicini L. , Foret F. , Bocek P. 
Published: May 2005

AbstractCapillary electrophoresis (CZE), with hydrodynamic injection and UV detection, was applied to the separation of enantiomeric and diastereoisomeric Co (III) complexes.
Separation of saccharides on cross linked chitosan beads with microcolumn liquid chromatography
Authors: Jinno Kiyokatsu , Takayarna Katsumi 
Published: May 2005

AbstractPorous chitosan beads cross‐linked by hexamethylene‐bis‐2,3‐epoxypro‐pyldimethylammonium chloride were methylated to prevent adsorption of solutes on the hydroxy groups and to be used as the stationary phase in liquid chromatography. The beads were derivatized without loss of their gel permeability. Separation of some monosaccharides was achieved with the beads when boric acid solution was used as the mobile phase. Resolution for monosaccharides was remarkably improved by selecting a suitable pH and concentration of boric acid in the mobile phase. In order to detect saccharides by UV, apostcolumn derivatization method with 2‐cyanoacetamide was adopted.
Supercritical fluid chromatography–supersonic jet spectroscopy: II. Capillary column SFC with a sheath‐flow nozzle
Authors: Goates Steven R. , Sin Chung Hang , Simons John K. , Markides Karin E. , Lee Milton L. 
Published: May 2005

AbstractSupersonic jet spectroscopic detection has been successfully coupled to capillary supercritical fluid chromatography by introduction of the supercritical effluent into a secondary flow of argon, before supersonic expansion of the combined flow through a converging nozzle. At pressures of 6–10 atm, the flowing sheath of argon efficiently carries eluting sample through a 25‐p.m nozzle orifice into the supersonic jet. Dead volumes are negligible in this arrangement, and high‐resolution fluorescence excitation spectra are obtained. Perylene and benzo[a]pyrene were selectively detected in a standard reference coal tar sample at detection limits of 150 pg and 5 ng, respectively.
Chiral separation of optical isomeric drugs using micellar electrokinetic chromatography and bile salts
Authors: Nishi Hiroyuki , Fukuyama Tsukasa , Matsuo Masaaki , Terabe Shigeru 
Published: May 2005

AbstractSeparation of optical isomeric drugs using micellar electrokinetic chromatography and bile salts as surfactants was studied. Optical isomers of diltiazem hydrochloride, trimetoquinol hydrochloride, and other drugs were separated successfully using chiral bile salts under neutral or alkaline conditions. Capacity factors were determined from the migration times of the solute, the micelle, and methanol. The effects of bile salt species or structures and of the pH value of the buffer solution were investigated. A possible chiral separation mechanism is suggested.
Multidimensional gas chromatography: State of the art
Authors: Himberg Kimmo , Sippola Erkki , Riekkola Marja‐Liisa 
Published: May 2005

AbstractGas chromatography (GC) is one of the most important techniques of organic analytical chemistry. It is widely used in the analysis of complex samples in environmental and medical applications. In order to reliably identify and quantitate the analyte that often exists at a residual concentration level, the GC system must in many cases have a separation power that cannot be achieved using one column within a reasonable analysis time. An extremely high resolution can be achieved by two‐stage GC (multidimensional GC, two‐dimensional GC), where the sample flows of two GC columns have been connected on‐line by a valve or valve system in such a way that only a selected fraction from the partly separated sample eluting from the first column can be transferred to the second column for further separation. This review describes the development of the technique and discusses areas of its applicability.
Supercritical fluid chromatography with Fourier transform infrared and mass spectrometric detection of peracetylated nitrogen derivatives of monosaccharides
Authors: Calvey Elizabeth M. , Roach John A. G. , Taylor Larry T. , Palmer James K. 
Published: May 2005

AbstractSugar oximes can be derivatized to yield both the peracetylated oxime and nitrile. The peracetylated oximes do not elute under isothermal (i.e., 200°C) gas chro‐ matography (GC) conditions. When a seven‐component derivatized sugar mixture, as determined by GC, was chromatographed under supercritical fluid chromatography (SFC) conditions with a cyanopropyl capillary column, at least 17 peaks were observed. In an effort to identify the additional derivatization products, the eluates were sub‐ jected to SFC‐FTIR and SFC‐MS. The spectral data indicate that cyclic and acyclic oximes as well as nitrile were formed as part of the derivatization method.
Microbore packed column supercritical fluid chromatography using a new polymer stationary phase
Authors: Liu Yan , Yang Frank , Pohl Chris 
Published: May 2005

AbstractPacked capillary and microbore column supercritical fluid chromatography (SFC) using a newly developed, highly cross‐linked ethylvinylbenzene and divinylbenzene (EVB–DVB) polymer as the packing material is presented. The EVB–DVB polymer stationary phase has been developed specifically for microbore packed column SFC applications. Compared to silica‐based packing materials, the EVB–DVB polymer is much more inert and free of active adsorption sites, has very good temperature and pressure stabilities, and is compatible with common organic solvents and aqueous samples (pH 0 to 14). The capillary and microbore columns packed with the EVB–DVB polymer have been used successfully to separate a number of polar and nonpolar compounds such as alkanes, free fatty acids, aromatic amines, and cyclic amines using pure supercritical CO2 as the mobile phase. The experimental results indicate that the retention mechanism of polar and nonpolar compounds on the EVB–DVB polymer stationary phase is governed by the surface adsorption–desorption that is an apolar–apolar interaction; the retention mechanism also is significantly influenced by the π–π surface interaction in π‐electron‐rich solutes because of the high density of π‐electrons associated with the aromatic components of the stationary phase. Some important practical aspects and comparisons between capillary and microbore packed columns in SFC applications are also discussed.
Polycarbonates as stationary phases for aqueous and acidic samples in capillary gas chromatography
Authors: Ghaoui Labib , Bonadies Joseph 
Published: May 2005

AbstractPolycarbonates were evaluated as stationary phases for capillary gas chromatography. Advantages of these resins are their high thermal stability and inertness to water. Long column lifetimes are exhibited for analysis of difficult samples such as acrylic acid in an acrylamide/water solution. The chromatographic behavior and typical applications are discussed.
Evaluation of sulfur chemiluminescence detection in supercritical fluid chromatography
Authors: Pekay Lars A. , Olesik Susan V. 
Published: May 2005

AbstractThe sulfur chemiluminescence detector was optimized for the analysis of organosulfur compounds by supercritical fluid chromatography. The flame gases used in this study were hydrogen and air. The highest sensitivity was found when a fuel‐rich flame was used. The noise characteristics of the detector were determined. Flicker noise is the primary source of noise in this detector when analyte is present. The linear dynamic range of the detector under supercritical fluid chromatography conditions was typically three orders of magnitude. For the optimum flame gas conditions, the detection limits for two‐and three‐ring organosulfur compounds were 10–1400 pg injected. The detection of sulfur in high molecular‐weight polymers was also demonstrated.
Stopped‐flow FTIR detection in capillary supercritical fluid chromatography
Authors: Raynor Mark W. , Bartle Keith D. , Clifford Anthony A. , Cook Bernard W. 
Published: May 2005

AbstractA stopped‐flow procedure for capillary supercritical fluid Chromatography with Fourier transform infrared detection is described. The flow of mobile phase is stopped so that the analyte peak is held under liquid conditions in the flow cell while FTIR scans are recorded. An increase in the IR spectrum signal‐to‐noise ratio is demonstrated during the analysis of a polymer additive.
Technique for injecting very large volumes in capillary supercritical fluid chromatography
Authors: Hirata Yukio , Kadota Yasuhiko , Kondo Tadashi 
Published: May 2005

AbstractA new technique for injecting very large volumes was developed for capillary supercritical fluid chromatography, which is based on dilution and venting techniques. Dilution of sample solution with carbon dioxide mobile phase made the selective venting of sample solvent very effective. Pressure at the end of the precolumn was also an important parameter for venting. With this method, injection of 100‐μL volumes was performed within 15 min. On‐line coupling of liquid chromatography to capillary supercritical fluid chromatography was demonstrated.
Determination of aldrin in natural matrices by gas chromatography following supercritical fluid extraction
Authors: Murphy Brett J. , Richter Bruce E. 
Published: May 2005

AbstractThe effectiveness of extracting aldrin from several natural food matrices using supercritical fluid extraction (SFE) was examined. Extraction efficiency was optimized by varying the extraction time and pressure using carbon dioxide as the extraction fluid. The extraction system was coupled directly on‐line with capillary column gas chromatography (GC) using flame ionization detection (FID). Results were linear over three orders of magnitude. Recoveries averaged 100% at 100 ppm. Reproducibility for all samples was less than 3.8% relative standard deviation. The minimum detectable limit for the system with FID was 1.20 ppm (S/N = 3). The use of off‐line SFE with GC and electron capture detection (ECD) was found to reduce the minimum detection level (MDL) to the sub‐ppb range (0.23 ppb), while recovery at 10 ppb was 96% with 3.1% RSD.
Quantitative determination of adsorption‐active silanol groups on the surface of reversed‐phase sorbents by microcolumn LC
Authors: Trushin Sergei A. , Kever Jeno J. , Vinogradova Lyudmila V. , Belenkii Boris G. 
Published: May 2005

AbstractA method for quantitative determination of residual silanol groups on the surface of reversed‐phase sorbents with the aid of microcolumn chromatography has bee developed. This method is based on the linear dependence of retention coefficients of phenol and benzyl alcohol on the surface concentration of silanol groups for reversed‐phase sorbents. Some commercial reverse‐phase sorbents were characterized.
Microcolumn liquid chromatography with sample induced internal pH gradient
Authors: Šlais Karel 
Published: May 2005

AbstractAn internal pH gradient of a wide renge of pH can be developed using the pumped mobile phase containing only a few [3–6] simple buffering salts which differ in pka values by about 1 pka unit or less. The use of several types of surface ionizable groups allows the internal pH gradient to be effective not only for separation of ampholytes but also for separation of anions of both strong and weak acids. The internal pH gradient can be induced simultaneously with solute introduction into the separation column. For this new method, the term “sample induced internal gradient” (SIIG) of pH was suggested. The method is demonstrated by separation of model mixtures of UV detectable anions and ampholytes on a dynamically modified microcolumn.