British Library Electronic Table of Contents (United Kingdom)

Trapezblechstege im Bruckenbau kommen trotz der groen Vorteile, die diese Bauweise bietet, in Deutschland bisher nur an einem Pilotprojekt zur Anwendung. Durch die charakteristischen Eigenschaften des Trapezbleches entstehen konstruktive und wirtschaftliche Vorteile gegenuber herkommlichen Bruckenbauweisen. Allerdings lassen die aktuell gultigen Regelwerke aufgrund fehlender Kenntnis zum Tragverhalten und mangelnder Erfahrung keine wirtschaftliche Ausbildung zu. Dies zeigt sich am Beispiel des Pilotprojekts. Die Ausbildung der Verbundfuge wurde hier nur sehr unbefriedigend gelost und verdeutlicht somit die Notwendigkeit einfacher und praktikabler Verbindungsmoglichkeiten. Am Institut fur Leichtbau Entwerfen und Konstruieren der Universitat Stuttgart wurde in Zusammenarbeit mit dem Institut...

Energy Technology Data Exchange (ETDEWEB)

This article gives a survey of the history, properties and applications of 'Kevlar' aramide fibers. For example, the 'Kevlar' para-aramide fiber is used in compound materials in ship-, aircraft- and vehicle construction. 'Kevlar' is used as a replacement for asbestos, for example in brakes, clutches and seals or as rubber reinforcement (tyres, conveyor belts, hoses). The aramide fibers also offer manufacturers of ropes, hawsers and cables a near ideal range of properties. (MM).

Energy Technology Data Exchange (ETDEWEB)

MRT is able to demonstrate arteries while MR angiography can quantify blood flow by a non-invasive method. In the present paper blood flow measurements were carried out in four selected cases on the basis of phase mapping. In 3 patients with lesions in the pelvis or thigh, angiography was performed in order to localise the stenosis or occlusion and this was followed by qantitative blood flow measurements. The results showed that angiography may not always provide all necessary information concerning a haemodynamically significant stenosis. The method may also be used for quantifying blood flow in the renal arteries and that it has significant advantages over the colour Doppler method. (orig.).

Energy Technology Data Exchange (ETDEWEB)

Computerized descriptions of isothermal, multi-stage creep fatigue load were established for one melt each of steels of the type 1%CrMoNiV and 12%CrMoV and were implemented in the service life prediction program SARA 2. SARA 2 predicts the time and number of cycles to incipient cracking for a given number of part cycles on the basis of rules for description of cyclic deformation and damage and of a generalized damage accumulation hypothesis. [German] Fuer je eine Schmelze der Staehle vom Typ 1%CrMoNiV and 12%CrMoV wurde eine rechnergestuetzte Beschreibung fuer isotherme mehrstufige Kriechermuedungsbeanspruchung erstellt und in ein Lebensdauerzaehlerprogramm SARA 2 implementiert. Auf der Grundlage von Regeln zur Beschreibung von zyklischer Verformung und Schaedigung unter Anwendung der verallgemeinerten Schadensakkumulationshypothese ermittelt SARA 2 fuer beliebig vorgebbare Teilzyklen einen Vorhersagewert fuer die Anrissdauer und die Anrisswechselzahl. (orig.)

Energy Technology Data Exchange (ETDEWEB)

Leakfree compression of gaseous liquids prevents impurities resulting from entry of lubricants and abrasive particles and is therefore an important requirement on modern compressors. Another requirement voiced increasingly often is the reduction or even prevention of problematic off-gases and contaminated residues of libricating oils. Further, compressors should have high corrosion resistance, low noise, a long service life and high reliability. Membrane compressors are largely able to meet these requirements. The article describes the technical concept and applications of membrane compressors. (orig.) [Deutsch] Umweltschutz und steigende Forderungen der Industrie an die Reinheit technischer Gase verlangen Kompressoren, die weitgehend leckagefrei verdichten und keine Verunreinigungen des Gases durch Schmierstoffe und Abrieb hervorrufen. Immer haeufiger wird in diesem Zusammenhang die Reduzierung oder sogar die Vermeidung von schwer zu entsorgenden Abgasen und kontaminierten ...

Energy Technology Data Exchange (ETDEWEB)

Endoluminal vascular prostheses that can be implanted by percutaneous routes represent the most recent development in vascular interventional radiology. Various commercially available types of prosthesis are presented and the construction principles and applications are described. At present secure indications for the implantation of endoluminal prostheses are limited to the elimination of aneurysms and arteriovenous fistulae of the large vessels near the trunk in sections that do not cross a joint. The wide use in peripheral occlusive diseases cannot yet be recommended because confirmed data are not available. (orig.) [German] Endoluminale Gefaessprothesen, die perkutan implantierbar sind, stellen die juengste Entwicklung in der vaskulaeren interventionellen Radiologie dar. Verschiedene kommerziell erhaeltliche Prothesentypen werden vorgestellt, ihr Konstruktionsprinzip und ihre Applikation erlaeutert. Die gesicherten Indikationen zur endoluminalen Prothesenimplantation beschraenken ...

Energy Technology Data Exchange (ETDEWEB)

The results of the experiments on the pressure oxidation of oil and fat in waste waters shows that the final COD and TOC values decrease with growing temperature and reaction time and decreasing initial concentration. Oxidation of oil and fat in waste water is no straight forward procedure. Therefore it should be compared in the individual case with laternative methods in terms of cost and economic efficiency. (EF) [Deutsch] Die Ergebnisse der Versuche zur Druckoxidation von Oel und Fett in Abwaessern zeigten, dass sich die CSB- und TOC- Endkonzentration verringerte mit steigender Temperatur, Reaktionszeit und verringerter Ausgangskonzentration. Die Oxidierbarkeit von Oel und Fett in Abwaessern ist sehr schwierig. Deshalb sollte in jedem Einzelfall ein Vergleich mit alternativen Verfahren bezueglich Aufwand und Wirtschaftlichkeit vorgenommen werden. (EF)

Energy Technology Data Exchange (ETDEWEB)

The precipitation hardened, ferrite-pearlite medium-carbon steels microalloyed with vanadium (AFP steels) have been developed over the last few years as materials allowing processing by controlled, continuous cooling down from forging temperatures, for achieving benefits such as reducing the number of required heat treatment and working processes and saving expensive alloying materials. Due to their cost-saving advantages, the steels rapidly have been accepted as an alternative material to the quenched and tempered steels and re particularly used for fabrication of automobile parts. Their drawbacks however are the lower yield strength, and low ductility and toughness as compared to the heat-treatable steels. The research project therefore was intended to enhance the properties of the microalloyed, medium-carbon steels and widen their applicability by establishing further and improving existing thermomechanical treatment processes that will considerably improve the steels` strength and ...

Energy Technology Data Exchange (ETDEWEB)

The textbook is primarily intended for radiologic staff and radiologic safety officers and gives information on the current regulatory provisions of the German X-ray Ordinance, applications of X-rays, quality assurance, organisational aspects of film processing and quality requirements of X-rays. An annex lists the guidelines of the Bundesaerztekammer (German National Chamber of Physicians) relating to quality assurance aspects, and further useful information on commercially available film-screen systems, the various associations of physicians in Germany, and requirements and performance of radiation surveys. (vhe) [Deutsch] Das vorliegende Lehrbuch, das sich vor allem an das technische Personal und an Strahlenschutzbeauftragte wendet, unterrichtet ueber die derzeit gueltigen Bestimmungen der Roentgenverordnung, die Anwendung von Roentgenstrahlen, ueber Qualitaetssicherung, die Organisation der Filmverarbeitung sowie ueber die Anforderungen an die Qualitaet von ...

Energy Technology Data Exchange (ETDEWEB)

Modern commercial alloys are not suited for future steam turbines of operating temperatures beyond 700 C. {gamma}'-hardened alloys like Waspaloy have good mechanical characteristics but have defects when large batches are melted. {gamma}'/{gamma}''-hardened alloys like Inconel 706, on the other hand, are easy to produce but have insufficient microstructural long-term stability and insufficient creep strength. Mixed crystal solidified alloys like Inconel 617 have excessive yield stress at forging temperatures. Two new alloys were therefore developed. Results so far show that they have good production characteristics but insufficient mechanical characteristics. The reasons for this are currently under investigation. (orig.) [German] Die heutigen kommerziellen Legierungen sind nicht geeignet fuer den Einsatz in zukuenftigen Dampfturbinen mit Betriebstemperaturen oberhalb 700 C. {gamma}'-gehaertete Legierungen wie Waspaloy zeigen zwar gute ...

Energy Technology Data Exchange (ETDEWEB)

For location of leakage at district heating pipelines several techniques are available today. If there is no wire bound lead monitoring system installed, the DH company has to apply mobile methods for detection and location and if possible characterization of leakage. Most mobile methods available today are restricted in application and often they cause supply disconnections, especially the location of very small leaks is difficult. The Institute for Environmental, Safety and Energy Technology (UMSICHT) has tested a new developed method that can be executed by own employees of DH companies that can be realised parallel to normal supply mode, and that is able to locate and characterize even very small leakages. (orig.) [Deutsch] Zur Lecksuche an Fernwaermeleitungen stehen verschiedene Techniken zur Verfuegung. Wurde beim Bau der Fernwaermetrasse kein drahtgebundenes Ueberwachungssystem eingebaut, ist der Netzbetreiber auf mobile Lecksuchmethoden angewiesen. Die herkoemmlichen mobilen ...

Energy Technology Data Exchange (ETDEWEB)

Steam turbines of the new power plant generation enable the realisation of over-critical steam parameters with 600 C and 300 bar by means of simple and double resuperheating. Extensive research work in the field of material technology has provided the pre-conditions. Forged pieces, castings, high-temperature ferritic 9 - 10 % CrMoV steels, which are additionally alloyed with niobium, nitrogen and wolfram, are used in steam turbines. A proof of strength for shaft and cast steels is available by means of a long-term stress-rupture test of up to max. 60,000 hours. The strength of turbine steels exceeds the one in tube and header steels (x 10 CrMoVNbN 9 1). (orig./MM) [Deutsch] Dampfturbinen der neuen Kraftwerksgeneration erlauben heute die Realisierung von ueberkritischen Dampfparametern mit 600 C und 300 bar mit einfacher und zweifacher Zwischenueberhitzung. Umfangreiche werkstofftechnische Forschungsarbeiten haben dafuer die Voraussetzung geschaffen. Zur Anwendung ...

Energy Technology Data Exchange (ETDEWEB)

Alloyed steels containing retained austenite after martensitic hardening are widely applied in technical practice. Although many practical investigations have been made into the mechanical behaviour of composite microstructures with retained austenite, there is still a lack of knowledge concerning their fatigue and crack propagation behaviour. For this reason, the author investigated the effects of retained austenite concentration and stability on the transformation and deformation behaviour of hardened states of the steels X210Cr12 and 100Cr6. For this purpose, monotone tensile tests, cyclic tensile pressure tests, and supplementary crack propagation experiments were carried out. The concentrations of retained austenite were varied between 10 and 100% by volume by means of different heat treatments. [Deutsch] Legierte Staehle, die nach martensitischer Haertung noch Restaustenit enthalten, finden in der technischen Praxis verbreitete Anwendung. Zum mechanischen ...

Energy Technology Data Exchange (ETDEWEB)

The high-speed direct-injection diesel engine for passenger cars has been a resounding success in the marketplace in the last few years. This was due to an intensive development process as a result of which the direct-injection diesel engine for passenger cars is currently setting new standards with regard to performance and fuel consumption in spite of the constant tightening of emission regulations. Of particular importance in this context is exhaust gas recirculation (EGR). This technology permits a considerable reduction in nitrogen oxide emissions, which are especially critical in the case of the direct-injection diesel engine. In addition, continuing development of supercharging technology, in particular the turbocharger with variable turbine geometry, have allowed further improvement of the full-load behaviour and the engine response and a considerable reduction in the fuel consumption of direct-injection diesel engines. This FVV paper deals with the fundamentals of the ...

Energy Technology Data Exchange (ETDEWEB)

Low-cost titanium alloy components are getting increasing attention in aerospace applications. Cost reductions are possible in the alloys themselves and in the production techniques. The former aspect is less promising as titanium alloys are costly to produce. Of course, there are some new developments like the (alpha plus beta) alloy Ti-6 Al-2 Fe-0.2 Si (TIMETAL 62S) and the beta-alloy Ti-6.8 Mo-4.5 Fe-1.5 Al (TIMETAL LCB), in which low-cost iron replaces costly beta alloying elements like vanadium or molybdenum, but these will be used mainly on the mass production markets, e.g. motor car construction. In consequence, optimisation of production methods is the more promising option. Near net shape processes will reduce the production cost and improve the fly-to-buy ratio. Some of these production processes are explained. [Deutsch] Die Herstellung preiswerter Bauteile aus Titanlegierungen gewinnt auch in der Luft- und Raumfahrt zunehmend an Bedeutung. Zwei Wege werden hier beschritten: ...

Energy Technology Data Exchange (ETDEWEB)

The comprehensive survey explains the indications and the specific value of the modern tomographic modalities with respect to the various diagnostic issues. Numerous reproductions of CT, MRI, US scans illustrate the aspects discussed. (orig./CB) [German] Bildgebende Verfahren kommen bei der Abklaerung von Erkrankungen des weiblichen Urogenitaltrakts ergaenzend zu der klinischen Untersuchung zur Anwendung. Kongenitale Uterusanomalien werden primaer mit der HSG oder der Laparoskopie diagnostiziert. Zusaetzlich koennen der transvaginale US und in unklaren Faellen die MRT eingesetzt werden. Die Diagnose entzuendlicher Erkrankungen des weiblichen Genitaltrakts erfolgt in der Regel klinisch. Schnittbildverfahren werden bei therapieresistenten, komplizierten Faellen angewendet. Initial werden benigne Neoplasien des Uterus mit dem transvaginalen US abgeklaert. Eine Verdickung des Endometriums ist dabei ein unspezifischer Befund und kann auf eine Hyperplasie, Polypen oder ...

Energy Technology Data Exchange (ETDEWEB)

Purpose: The aim of this study was to evaluate the accuracy of MRI in the measurement of cartilage thickness of the ankle joint in comparison to pathologic and histologic specimens. Patients and methods: The ankle joints of four fresh cadaver feet were imaged on a 1.5 T MR-unit in the coronal plane. Standard T{sub 1}-weighted spin echo (SE) and a T{sub 1}-weighted 3D-GE (FLASH-3D) sequence with fat saturation were applied. Following MR imaging, the talus was explanted and cut parallel to the MR images for macroscopic evaluation and histologic specimens were prepared. MRI measurements of the cartilage thickness of the talus were carried out in two ways: Without and with consideration of a transition zone of intermediate signal intensity between hyperintense cartilage and hypointense cortical bone. The data were compared with the anatomic specimens as the gold standard expressing the difference as a percentage value. On histologic specimens thickness of deep calcified cartilage layer was ...

Energy Technology Data Exchange (ETDEWEB)

Nuclear medicine and magnetic resonance imaging (MRI) are widely used in cardiac diagnostics. Both techniques have been carefully evaluated and are equivalent for the assessment of regional and global wall motion as well as the evaluation of ejection fraction and cardiac volumes, though MRI is herein currently seen as gold standard. For evaluation of myocardial perfusion, extensive data exist for nuclear imaging, that, next to high diagnostic accuracy for evaluation of coronary artery disease, show incremental prognostic information and allow for independent risk stratification. Because of rapid technical advance, myocardial perfusion imaging has also become feasible with cardiac MRI. Results of recent studies are promising, but the data are few compared to perfusion scintigraphy. For viability assessment in patients with ischemic cardiomyopathy, positron emission tomography (PET) with FDG is currently seen as gold standard. However, single photon emission computed tomography (SPECT) ...