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This paper provides some results of the research works at low pressure components of steam turbines and some construction solutions resulting in a modernisation. The problems of turbine phases for the transonic flow are analysed with respect to reducing profile and margin losses. The origin and flow of wet steam and its influence on corrosion and erosion is investigated. Inlet and outlet casing of the flow channels and transfer diffuser between second last and last phase are mentioned. (orig.) [Deutsch] Im Beitrag werden einige Ergebnisse der Forschung der Teile von ND-Teilen der Dampfturbinen angegeben, und werden irgendeine Konstruktionsloesungen, die fuer ihre Modernisierung guenstig sind, beschrieben. Kurz wird die Problematik der Turbinenstufen fuer die transsonische Stroemung analysiert, mit Hinsicht auf die Erniederung der Profil- und Randverluste. Weiter ist die Aufmerksamkeit der Entstehung und Stroemung des Nassdampfes im Zusammenhang mit dem Phaenomen ...

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Sprayforming offers the possibility to produce a variety of preforms in a single step directly from the melt. Numerous processing parameters ensure high flexibility but require detailed knowledge concerning the microstructure of sprayformed material depending on chemical composition and processing parameters. Within the current study fundamental investigations using unalloyed and low alloy steel grades (C15, C105, 100Cr6) for sprayforming of plates and billets have been performed concerning the influence of chromium and carbon content and selected processing parameters. Sprayformed preforms revealed austenite grain sizes up to 500 {mu}m depending on the development of porosity. Different types of porosity have been detected which can be associated with incomplete densification due to high cooling rates, solidification shrinkage and entrapped nitrogen. Atomisation gas pressure and carbon content are parameters of primary importance. (Abstract Copyright [2003], Wiley Periodicals, Inc.) ...

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The fibre reinforcement of ceramic materials is used above all to improve the toughness and tolerance of damage, compared to unreinforced monolithic ceramics. This improvement is made possibly by the bridging effect of the cracks by the fibres in crack propagation in the matrix. In this work, the crack bridging effect of the fibres is included in a bridge stress equation, in which a clear relationship between bridge stress and crack opening is determined. The most important step for deriving the bridge stress law was determining the probability of failure of a fibre for a given axial stress curve. One relied on the micromechanical analysis of Hutchinson and Jensen here, by which the boundary conditions in multi-fibre materials can be included and realistic assumptions can be made for the load transfer mechanisms in the fibre/matrix boundary surface. (orig./MM) [Deutsch] Die Faserverstaerkung keramischer Werkstoffe dient vor allem zur Verbesserung der Zaehigkeit und Schadenstoleranz ...

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This thesis deals with the analysis of dominant loss mechanisms in direct methanol fuel cells (DMFC) and hydrogen fed polymer electrolyte membrane fuel cells (PEFC) by means of experimental characterization and modeling work. Due to different fuels used in these two fuel cell types, the dominant loss mechanisms are different in their nature. All in-situ characterization techniques that are used in this work are based on a novel test fuel cell with embedded reference electrodes. The first part of this work presents a new concept for realizing a reference electrode configuration in a polymer electrolyte membrane fuel cell by means of laser ablation. The laser beam is used to evaporate a small gap into the electrode surface of a catalyst coated membrane (CCM) to isolate the reference electrode from the working/counter electrode (WE/CE). This method enables the simultaneous ablation of the electrodes on both sides of the CCM because the membrane is transparent for the laser beam. ...

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In the first part of this contribution, the definition of reference values is given and the theoretical and practical problems in the application of this concept are discussed. In this connection, the present resources on instrumentation and the technical requirements for dose assessment are described. In the second part, some consequences are taken and proposals for further actions are made. (orig.) [German] Im ersten Teil des Aufsatzes werden die Definition von Referenzwerten in der radiologischen Diagnostik untersucht und die theoretischen und praktischen Probleme der Umsetzung des gesamten Konzepts eroertert. In diesem Zusammenhang werden auch der gegenwaertige Geraetebestand und die technischen Voraussetzungen zur Dosisermittlung beschrieben. Im zweiten Teil werden daraus Schlussfolgerungen gezogen und Vorschlaege zum weiteren Vorgehen gemacht. (orig.)

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The knowledge shown in this work of the relationships between the oxidation stage of chromium, molybdenum and tungsten and their catalytic activity in some hydrocarbon reactions was achieved by the combination of separate investigations of reduction properties and the catalytic activity of the catalysts concerned. To characterize the electronic state of the reduced surfaces, X-ray photo-electronic spectroscopy was mainly used, supplemented by electron spin resonance. The catalyst activity was measured in conventional apparatus (flow, pulse and gradient-free reactors). (orig.) [Deutsch] Die in dieser Arbeit dargestellten Erkenntnisse ueber die Zusammenhaenge zwischen der Oxidationsstufe von Chrom, Molybdaen und Wolfram und ihrer katalytischen Aktivitaet in einigen Kohlenwasserstoffreaktionen wurden durch die Kombination getrennter Untersuchungen ueber Reduktionseigenschaften und katalytische Aktivitaet der betreffenden Katalysatoren erzielt. Fuer die ...

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The contribution outlines the current status of the building construction projects for the German Bundestag in Berlin. The following subjects are discussed: Energetic quality of the building, energy supply concept, integrated energy supply system, electric CHP systems, cogeneration (vegetable oil), aquifer storage (heat storage, cold storage), solar energy (photovoltaic energy conversion, thermal solar energy use), economic and ecological aspects. (HW) [Deutsch] Der vorliegende Beitrag gibt einen Ueberblick ueber den aktuellen Stand des Bauvorhabens des Deutschen Bundestages in Berlin. In diesem Zusammenhang wird auf folgende Themen eingegangen: Energetische Gebaeudequalitaet, Energieversorgungskonzept, Energieverbund, stromgefuehrte BHKWs, Kraft-Waerme-Kopplung (Pflanzenoel), Aquiferspeicher (Waermespeicher, Kaeltespeicher), Sonnenergienutzung (Photovoltaik, thermische Solarenergienutzung), Wirtschaftlichkeit und Oekologie. (HW)

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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 ...

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In view of current trends in motor car development, the author investigates the increasing conflict between higher comfort and lower fuel consumption. The conflict results mainly from insufficient cooling water heating with consumption-optimized engines. So far, it was never necessary to analyze heat flow after cold starting and heat-up of the powertrain, to develop strategies for heat storage and distribution, to remove heat sinks and to use components multifunctionally. The contribution shows that a general heat management strategy for the whole vehicle will result in high potential fuel savings and improved thermal comfort. Using the example of a latent heat store, heating strategies for the engine and transmission system on the one hand and the passenger compartment on the other hand are developed, and the advantages are presented in detail. [German] Abgeleitet aus den Trends in der Fahrzeugentwicklung wird auf den immer staerker werdenden Konflikt zwischen den ...

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The article explains why electric and gas utilities in Germany should not forget the domestic customers when deciding their key account management strategies and marketing policy in the competitive electricity and natural gas markets. Competition in the German energy sector has just begun, and so far the industrial customers have been absorbing most of the utilities` attention. The authors show that this is a short-sighted management strategy and present a number of reasons speaking in favour of bulding up structures or preserving the loyalty of domestic cutomers, as this customer group will finally play an important role in the utilities` efforts to keep their competitive edge. (orig./CB) [Deutsch] Wenn heute unter Marketingaspekt ueber Kundenbindung im Energiemarkt gesprochen wird, dann wird haeufig zuerst oder sogar ausschliesslich ueber die umsatzstarken Geschaeftskunden nachgedacht. Der Wettbewerb, vor allem im Bereich der Grosskunden, kuendigt sich in drastischen Einschnitten in ...

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To evaluate the usefulness of radiation therapy alternative to surgery for clinical N0-N1 non-small cell lung cancer (NSCLC). From 1976 through 1989, 116 patients with NSCLC without mediastinal involvement were treated with definitive radiation therapy alone at Gunma University Hospital. All patients were treated with once-daily standard fractionation using 10 MV X-rays. The total dose ranged from 60 Gy to 80 Gy. The actuarial 2- and 5-year survival rates of the entire group were 43% and 20%, respectively with a median survival time of 19 months. The survival of 76 patients with stage T2 tumors was significantly better than that of 28 patients with T3 tumors (mean survival time 21 versus 15.5 months; p<0.05). Sixty-two patients with tumors less than 5 cm in diameter had a 2-year progression rate of 20%, in comparison with 39% of 54 patients with tumors greater than 5 cm. The difference of survivals for these 2 groups was statistically significant. Twelve patients given a total dose ...

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One aspect of the research program SFB 570 'Distortion engineering' is the in situ X-Ray diffraction analysis of phases and residual stresses during complete heat treatment cycles. These investigations result in experimental evidence available for the extensive computations. The optimisation of the instrumentation will be reported. A surface decarburisation of samples made from the ball bearing steel 100Cr6 could be avoided for a temperature range from 800 to 900 C and a holding time of one hour by a combination of evacuate the furnace and using a certain nitrogen flow as protective gas. At lower temperatures small amounts of ferrite caused by an increased diffusion rate of carbon lead again to a surface decarburisation up to a depth of 2 {mu}m. It was proved that with an evacuation of the X-Ray beam path at constant power of the X-Ray source the intensity of diffraction lines could be increased by more than a factor of 4. The use of nitrogen as protective gas instead ...

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MRT criteria have been developed to distinguish between tumour and implant material following examination of 50 patients who had transsphenoidal hypophysectomies for tumours. Judgements were based on the postoperative hormonal status and the operation notes. Following contrast injection of Gd-DTPA and using T[sub 1] weighted spin-echo sequences, implant material appeared as sandwich-like, linear or circular structures. Residual recurrent tumour produced homogenous or non-homogenous aspects without marginal enhancement in 84% of cases. Postoperative displacement of the infundibulum to the opposite side was observed in 73% of patients with tumour remnants. Sensitivity of MRT was 70%, specificity 95%. There was a positive predictive value of 94% and a negative predictive value of 72% with an accuracy of 81%. This provides assistance in differentiating between tumour remnants and implant material. MRT is recommended as a method of examination for hypophyseal tumours to evaluate the success ...

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Industrial companies are being forced by increasingly restrictive environmental legislation to implement power station technology which is environmentally compatible and which conserves scarce resources. Gas and steam turbine power stations have been causing a sensation in this field for some time. This article gives an introduction to gas and steam turbine power stations in the 4 MW to 30 MW size range. The designs of the plants described here not only provide for electricity generation by gas and steam turbines however, but also designs specific to particular companies for process steam and district heating supply. (orig.) [Deutsch] Durch immer restriktivere Umweltschutzgesetze werden die Industrieunternehmen zu einer umwelt- und ressourcenschonenden Kraftwerkstechnik gedraengt. Auf diesem Gebiet sorgen nun seit geraumer Zeit GuD-Kraftwerke fuer Furore. In diesem Beitrag werden GuD-Kraftwerke in einer Groessenordnung zwischen 4 MW und 30 MW vorgestellt. Die ...

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Materials and methods: 12 patients with 22 coronary bypass grafts underwent intraoperative flow quantification using the transit time ultrasound method. These values were compared to postoperative MR phase shift measurements. Flow measurements were performed preoperatively in 28 coronary arteries of 20 patients. For flow measurement, we used a velocity-encoded k-space segmented gradient echo sequence with a temporal resolution of 110 or 125 ms, respectively. 6-8 pase shift images could be acquired during one cardiac cycle. Results: There was a significant correlation between intraoperative and flow measurements using velocity-encoded MR imaging (r=0.76, p<0.0001, t-test). Flow volumes determined by MR imaging were systematically larger than those determined by the transit time ultrasound method. Mean flow in coronary arteries was reduced in severely stenosed vessels (>70%) compared to normal vessels. Intra- and interobserver variability were 10.5 and 15% (coronary bypass ...

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For purposes of assessing the dumpability of wastes, Article 1 - Ordinance on the Environmentally Responsible Landfilling of Household Wastes (AbfAblV) - of the Ordinance on the Environmentally Responsible Landfilling of Household Wastes and Biological Waste Treatment Plants defines classificaton criteria for biologically and mechanically treated wastes destined for landfilling. The practical experiences that have been gathered with these classification criteria and values were evaluated in a questionnaire-based survey. This was done in particular for the purpose of verifying and validating proposals on the methodology of respiration and fermentation tests. A general finding has been that the application and implementation of the regulations of the AbfAblV is fraught with difficulties. This is evident for one thing in the frequency of analyses and for another in the difficulty of complying with the limit values of the classification criteria. The authors are in support of demands that ...

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The experimental effect investigation programme on Zircaloy-4/air oxidation was pursued and expanded to isothermal specimen exposure and the comparison of the oxidation between the atmospheres Ar/O{sub 2} and air. In close connection with the EC project OPSA, which is meanwhile terminated, the investigation concerned specimen exposure in a thermobalance to flowing atmospheres, namely dry Ar/O{sub 2} of composition 80/20 or synthetic air, respectively. As test parameters the linear heat-up rate was varied in the range 5 to 40 K/min and the ramp or holding temperature between 800 and 1500 C. Mass increase and reaction rate were continuously recorded or evaluated in temperature/time dependence. The oxide scale growth was found to be accompanied by colour changes, crack formation and spalling of layers, as well as by dimensional substrate growth, which are the reasons for the observed kinetic results. The microstructural investigation confirms nitrogen to be essentially responsible for the ...

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Nuclear energy will have to cope more and more with a rapid changing environment due to economic competitive pressure and the deregulatory progress. In current economic environment, utilities will have to focus strongly on the reduction of their total generation costs, covering the fuel cycle costs, which are only partly under their control. Developments in the fuel cycle will be in the short-term rather evolutionary addressing the current needs of utilities. However, within the context of sustainable development and more and more inclusion of externalities in energy generation costs, more performing developments in the fuel cycle could become important and feasible. A life-cycle design approach of the fuel cycle will be requested in order to cover all factors in order to decrease significantly the nuclear energy generation cost to complete with other alternative fuels in the long-term. This paper will report on some of the trends one could distinguish in the fuel cycle with emphasis ...

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A new emissivity measurement device with inductive sample heating is described. The disc shaped samples can be measured between 800 C and 2000 C in vacuum or in each available gas atmosphere. Two kinds of surface temperature measurement methods are described, one by measuring in a blackbody hole and one by measuring at the surface without additional measures to correct emissivity. Total normal and spectral emissivity at wavelengths between 0,5 {mu}m and 8,3 {mu}m of various high temperature materials like platinum and Pt-Rh-alloys, siliconcarbide and molybdenum disilicide have been measured. From the investigated materials a few have been selected as reference samples for comparative emissivity measurements fullfilling the requirement of stability on air up to 400 C to 1000 C in order to ensure reproducibility of the results at different measurement conditions in air and in vacuum. (orig.) [Deutsch] Der Aufbau einer neuen Messapparatur fuer Emissionsgradmessungen bei Temperaturen ...

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Already, MR Imaging is superior in diagnostic imaging of joints in many cases; however, there have been recent developments, which are the subjects of this paper. With gradient-echo sequences acquired in 3D technique, it is possible to produce high-resolution images of joints in acceptable scantime, because gradient-echo sequences are less time-consuming than convential SE sequences. With the acquisition of two echoes, phase difference between water and fat protons have to be considered. 3D Imaging is capable of displaying complex pathology in a superior way, which should be useful in preoperative planning. Tissue contrast is altered by fat saturation or magnetization transfer in order to achieve better conspicuity of lesions. Although diagnostic value of some of these options is not yet clear and further clinical studies are needed, they are a promising possibility for improving MR Imaging of the joints. (orig.) [Deutsch] In der Gelenkdiagnostik gibt es einige neuere Entwicklungen in ...

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It is necessary to measure strength and creep behavior to guarantee the safe and reliable usage of refractory alloys at extremely high temperatures. In the literature there is very little information available about the properties of Mo-Re alloys at temperatures higher than 1000 C. A special test facility has been designed and built for stress-rupture testing at very high temperatures (up to 3000 C) of refractory metals and alloys in inert atmospheres. - The stress-rupture strength as well as the creep behavior of molybdenum-rhenium alloys with rhenium contents between 41 and 51 wt.% have been determined at temperatures ranging from 1200 to 2000 C, and rupture times of up to 10 hours using this facility. Previous measurements of stress-rupture strength and creep behavior of pure rhenium have been compared with the measurement results of Mo-Re alloys. - The discussion of the values measured is based on metallographic test results and scanning electron microscopy (SEM) images of Mo-Re ...

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The evaluation of possible manufacture-based defects in turbine shafts and housings for component serviceability relevance is of particular interest not only in post-manufacturing NDT but also in evaluation of NDT results obtained by in-service inspections of components with long service lives. The results discussed in the paper are summarized as follows: Most of the examined natural defects in the forgings and castings behave like cracks under the simulated operating conditions and hence may well be evaluated by fracture mechanical methods for their serviceability relevance determined by crack propagation under fatigue, creep and creep-fatigue stress. The empirical correlation of true defect size and US testing results (echo signal, echodynamics, attenuation) permits improved determination of true defect sizes in the turbine components. Care has to be taken to select the proper testing and evaluation methods in compliance with defect types. (orig./MM) [Deutsch] Die ...

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Investigation of an HP-blade damage in 1996 and an MP-blade damage in 1007 at the mounting showed that fretting and creep fatigue had caused the damage. Break-down occurred when creep-related cracks developed between radial bridge to the upper blade tooth and weight relief boreholes. After disassembly of the HP-blades the lower blade tooth was found to be cracked after fretting (some cracks along the whole length of the tooth). The lower teeth of MP-bladedes showed merely superficial cracks (depth about 0.4mm). The massive cracks of the lower blade tooth were caused by instationary clearance changes combined with hard blade underground.(orig.) [German] Das Ergebnis der Untersuchung nach einem HD-Schaufelschaden 1996 sowie einem MD-Schaufelschaden 1997 an der Vierzackenfussbefestigung ergab Zeitstanderschoepfung und Fretting als auszuloesende Schadensmechanismen. Die Havarien wurden durch zeitstandbedingte Brueche zwischen Radienuebergang zum oberen Schaufelzacken ...

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A model for combined mass and heat transfer during nonisothermal gas absorption in a two-phase gas- liquid bubbly medium with a high gas content and/or large times of gas-liquid contact is suggested. Diffusion and thermal interactions between bubbles is taken into account in the approximation of a cellular model of a bubbly medium whereby a bubbly medium is viewed as a periodic structure consisting of identical spherical cells with periodic boundary conditions at a cell boundary. Distribution of concentration of dissolved gas, temperature distribution in liquid and coefficients of mass and heat transfer during nonisothermal absorption of a soluble pure gas from a bubble by liquid are determined. In the limiting case of absorption without heat release the derived formulas recover the expressions for isothermal absorption. (orig.). With 1 fig., 1 tab. [Deutsch] Es wird ein Modell vorgestellt, das den kombinierten Waerme- und Stoffaustausch waehrend der nichtisothermen Gasabsorption in ...

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Purpose: To assess the new method of 3-dimensional echocardiography in comparison to the 'gold standard' MRI as to its ability to calculate left ventricular volumes in patients with congenital heart disease. Materials and methods: Eighteen patients between the ages of 3.9 to 37.3 years (mean: 12.8{+-}9.7) with a geometrically abnormal left ventricle were examined using a 1.5 T scanner with a fast gradient-echo sequence (TR=14 ms, TE=2.6-2.9 ms, FOV=300-400 mm, flip angle=20 , matrix=128:256, slice thickness=5 mm, retrospective gating) in multislice-multiphase technique. Transthoracic 3D-echocardiography was performed with a 3.5 MHz transducer and a Tomtec {sup trademark} (Munich, Germany) system for 3D reconstruction. Results: Volume calculation was possible in all patients with 3D-echocardiography, but the muscle mass calculation only succeeded in 11 to 18 patients (61%) due to inadequate visualization of the entire myocardium. Comparing MRI and 3D-echocardiography, ...

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The ODS superalloys MA 6000 and MA 760 were investigated with regard to their behaviour under non-isothermal fatigue stress. For this purpose, strain-controlled thermomechanical and bithermal experiments with different phase relationships between strain and temperature were carried out on the one hand; on the other hand, the deformation behaviour under thermomechanical stress was modelled on the basis of isothermal cyclic creep data. The fatigue experiments show that a diamond-shaped cycle derived from the stress pattern of a turbine blade is clearly less critical than in-phase and out-of-phase cycles. The life of the diamond-shaped cycle is determined by oxidation-induced crack initiation and propagation and can be predicted easily with a suitable damage model. Important damage parameters required by the model can be obtained by the less complicated bithermal fatigue tests. Modelling of the TMF hystereses suggests that cyclic, non-isothermal deformaltion is determined mainly by ...

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Several components of high-temperature reactor units have roller bearings in order to carry out their motions without much friction. The use of such bearings poses friction and wear problems which cannot be mastered by commercial roller bearing technology. Possible improvements of coating, cage design and bearing materials as well as of their parameters were registered and studied. The service life of dry lubricated bearings was considerably improved. With a radial or axial load on the bearing of {>=} 10% of the static load, {approx_equal} 20x10{sup 6} rolling motions/actuations can be performed. The connections between surface compression and wear were determined, and optimum conditions for the transfer of lubricants from the cage onto the bearing race were worked out. Coating of corrosion-resistant roller bearing steels with the HRB-M{sub 0}S{sub 2} running-in coating could be proved. New cage designs and materials were tested with positive results. Alternative coatings (thin ...

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To study the biogeochemical behaviour, mobility and transport of trace metals in seawater (Se, Mo, Cd, Pb, Hg, Cu, Co, Fe, Ni, Zn), in suspended particulate matter (Mo, Cd, Pb, Cu, Co, Fe, Ni, Zn, Al, Mn) and in sediments of the inner and outer coastal regions, samples were collected on 3 separate cruises during a one year period (Mai 1993 - April 1994) at 20 stations in the coastal area of Mecklenburg-Vorpommern. Standard hydrographic parameters, nutrients and dissolved oxygen were also measured. Priority was taken to establish the methods for the determination of molybdenum and selenium. To study the behaviour of these two elements in detail, longterm measurements were carried out weekly between January 1993 and June 1994 at the `Messsteg/Warnemuende`. Because of parallel measurements correlations to biological, chemical and hydrographic parameters have been tested. The total database is summarized in the Appendix. The results are presented in 30 figures and 13 tables and are ...

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The nuclear structure of A {proportional_to} 100 nuclei has been studied in the frame of this thesis with a recently developed {beta} - {gamma} - {gamma} triple coincidence fast timing technique and different models such as shell model, hydrodynamic model, Nilsson and particle-rotor models. This technique which allows the measurement of the level lifetimes in the ps range has been applied at JOSEF at the research reactor DIDO of KFA Juelich in studes of the short-lived neutron-rich nuclei in the A {approx_equal} 100 region. Lifetimes of level in {sup 96},{sup 98},{sup 100} ZR, {sup 99},{sup 101}-{sup 104} Nb, {sup 100}-{sup 105} Mo have been measured, which are in many cases completely new, and otherwise more precise than previously published data. From the lifetimes of the members of rotational bands, the size of the nuclear deformations has been deduced. (orig./HSI). [Deutsch] Im Rahmen dieser Doktorarbeit wurde die Kernstruktur der A {proportional_to} 100 Kerne untersucht. Dazu ...

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Magnetic resonance imaging (MRI) of the lung is challenging because of substantial drawbacks. However, lung pathologies that are associated with increased attenuation values in CT enhance visualization in MRI: proton density is increased and tissue-air interfaces, resulting in susceptibility artifacts, are reduced in pneumonia, pneumonitis, edema, and carcinoma. On the other hand, many lung diseases result in shortness of breath, so that patients cannot hold their breath for long periods. Therefore, fast imaging techniques are required which should also allow for high spatial resolution so that small lesions can be detected. Calcifications and air pockets within lesions are not readily recognized with MRI. Thin section CT is standard for the diagnosis of pneumonia. With parallel imaging techniques, MRI examination of the lungs can be performed with short periods of breath holding, which allow for sub-centimeter resolution in the z-axis. Especially for follow-up examinations in ...

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Aim: The purpose of this prospective study was to evaluate the value of immunoscintigraphy (ISG) with anti-225.28S in clinically suspected ocular melanoma. Methods: For this purpose standardized ISG was performed in 36 patients using both planar acquisition and emission computed tomography (ECT). Ocular melanoma was present in 31 patients. In 21 patients therapy was enucleation of the eye. These specimens were evaluated by histology and immunohistochemistry in 11 of 21 patients. Results: Regarding the clinical diagnosis, ISG was positive only in 15 of 31 patients with ocular melanoma, regarding histology in 11 of 21 and regarding immunohistochemistry in 5 of 6 patients with a positive immunoreaction. 5 patients showed no immunoreactivity, their ISG was negative. Conclusion: Thus a good correlation between ISG and immunohistochemistry was observed. However ISG using the cutaneous melanoma antibody 225.28S cannot be recommended for the diagnostic work-up of an ocular melanoma considering ...

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The influence of a decarburisation process during austenitising of the through-hardenable rolling bearing steel 100Cr6 (SAE 52100) on the rim zone properties of the martensitic through-hardened material was investigated by means of material analysis and diffusion calculations. For this purpose, two specimens were prepared under defined heat treatment conditions, and the near-surface carbon distribution was determined micro-chemically by using secondary ion mass spectrometry (SIMS). In part 1 of the present work, these concentration profiles are compared with the depth variation of the micro-hardness and with the distance curves of the residual stresses and the line broadening ({l_brace}211{r_brace} {alpha}'-Fe diffraction line) both measured by X-ray diffraction (XRD). In addition, microstructure investigations were performed. In part 2, a refined kinetics model of a diffusion-controlled reaction based on the finite element method (FEM) will be applied to the decarburisation ...

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Magnetic resonance imaging (MRI) as a diagnostic imaging tool relies on the generation of magnetic fields, whereas the computerized tomography (CT) uses X-radiation. The fundamental principle of MRI is the magnetic resonance of paramagnetic atomic nuclei. These nuclei, as e.g. protons (= hydrogen nuclei), are aligned in required orientation by application of a strong magnetic field. Upon simultaneous application of an electromagnetic high-frequency field perpendicular to the axis of the basic magnetic field, and in response to periodical changing of the electromagnetic field at a given frequency, the originally aligned paramagnetic nuclei are forced into a movement similar to that of a ``whipping top``. When the resonance frequency is shut off, the nuclei return to their former, aligned positions, inducing a weak signal in a coil. The series of signals generated by multiple repetition of this process of excitation of nuclei and their return to aligned rest is used as input to a ...

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Purpose: The aim of this study was to test the feasibility of iliac artery stent placement under MR guidance with real-time MR radial scanning in an animal model. Materials and methods: The experiments were performed on three pigs in a 1.5 T scanner. Radial scanning with a gradient echo technique (T{sub R} 8.4 ms, T{sub E} 3.6 ms, flip angle 10 ) was used. A dedicated backprojector performed the reconstruction of the raw data in real-time. The resulting MR-images were displayed on LCD screens beside the magnet. The sliding window reconstruction technique allowed image acquistion at a frame rate of 16 images per second. MR-compatible self-expanding stents with a diameter of 8 mm and a length of 3 cm were placed into the left iliac artery. Their positions were verified by digital subtraction angiography (DSA) and compared to MRI. Results: All stents were successfully placed. Stent positions as monitored by real-time MR were identical to those seen on DSA images. The time needed for exact ...

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The oxidation of boron carbide in steam or air was recently extensively studied especially in Forschungszentrum Karlsruhe, Institut fuer Materialforschung. An important data set is available for the interaction modelling. An oxygen diffusion model through the superficial liquid boron oxide formed on the boron carbide external surface associated to a superficial reaction between the liquid boron oxide and steam is proposed to simulate the experimental kinetics from BOX rig and thermogravimetric tests on the interaction between steam and boron carbide at a temperature range 800 C to 1400 C. The oxygen diffusion model will be also useful to simulate interaction between boron carbide and Ar+O2 (air simulation) atmosphere when the steam pressure becomes zero. From the analysis of BOX rig experimental kinetics of non-condensable (H2, CO2, CO and CH4) gases we propose an oxygen diffusion model through the liquid boron oxide and a ''steam/liquid boron ...

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MRI provides a non-invasive diagnostic tool complementing echocardiography on one hand, and showing advantages over echocardiography, on the other hand, especially after corrective procedures. The multiple different MRI sequences need to be adapted to examinations of children and patients with congenital heart disease (CHD), and can be used to detect morphologic changes, blood-flow in the heart and thoracic vessels and diastolic or systolic function of myocardium. Several factors determine the success of the examination of a complex congenital heart disease or a postoperative situs. Pediatric radiologists and radiologists experienced in congenital heart diseases have to work in close cooperation. Echocardiography should be performed before MRI. The results of prior examinations and the clinical history of the patients, including possible palliative or reconstructive operations, must be available before MRI to guide the planning of the examination. With a systematic segmental approach ...

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Austenitic stainless steel (18% Cr, 12% Ni, Mo gradation between 0,06 to 3,6%) had been solution nitrided. By step-by-step removing, the samples could be prepared with various surface contents of nitrogen from 0.04 to 0.42%. In two test series the influence of nitrogen had been determined. The susceptibility against pitting corrosion of these samples had been tested by the chronopotentiostatical method. For the investigated steel composition and the used corrosion system there is no influence of molybdenum on the effectiveness of nitrogen. The effectiveness of nitrogen can be described by the factor 25 in the PRE. By the investigation of the surfaces with the XPS analysis, it could be shown that the passivation and the pit nucleation is influenced by nitrogen. In these ranges NO{sub x}, NH{sub x}, and NH{sub z}-spectra have been detected. Bound Mo was found in steels containing molybdenum. It is assumed that the repassivation mechanisms of N and Mo work independently of each other. ...

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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 ...

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Purpose: In the present study the reduction of artifacts using an extended CT scale technique was examined in 5 vitallium and 5 titanium-aluminium-vanadium tumor prostheses. Methods: 5 titanium-aluminium-vanadium and 5 vitallium distal femur Mutars {sup trademark} tumor prostheses (Mutars {sup trademark} - Modular Universal Tumor And Revision System) were implanted in 10 human femur specimens. 110 artifical drill hole lesions of 1 mm, 2 mm, 3 mm, 5 mm and 8 mm diameter were placed in the bone around the hexagonal stem of the tumor prosthesis and furthermore in the proximal part of the femur. All specimens were examined using conventional CT and an extended CT scale technique in a slice thickness of 3 mm. Results: In the proximal part of the femur all drill holes could be detected using 3 mm slices, no artefacts were observed. Along the hexagonal stem smooth lines arising from each hexagonal plane could be observed. This made it impossible to detect a 1 mm drill in 1 vitallium and in 1 ...

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We report for the first time about a micromachined mass flow sensor directly integrated between the double guidance and the needle seat into the body of a Common Rail (CR) injection nozzle. The thermal measurement principle was chosen because gaseous as well as liquid mass flows can be determined fast and precisely. Additionally, with glass-ceramic materials fabricated in a low cost batch process, a high temperature and especially pressure stable substrate can be used. The flow sensitive thin film is realized by an e-beam evaporated 110 nm thick molybdenum (Mo) layer. The latter is electrically characterized by the resistivity of {rho} = 8.2 x 10{sup -7} {omega} m ({+-}2%) at room temperature as well as by the first {alpha}=4.5 x 10{sup -4} K{sup -1} ({+-}5%) and second {beta}=3.0 x 10{sup -6} K{sup -2} ({+-}12%) temperature coefficients of resistance up to 300 C. The static temperature field at and around the thin film sensor on the glass-ceramic substrate is investigated with an IR ...