Elektrochemische Potentialmessungen (auch Potentialfeldmessungen) haben sich seit Jahren bewahrt, Bereiche mit aktiver chloridinduzierter Korrosion an tausalzexponierten Bauwerken, wie z. B. Bruckentafeln sowie Zwischendecks und Bodenplatten von Parkhausern und Tiefgaragen nachzuweisen. Bereits 1990 erschien die erste Fassung des Merkblatts B3 der DGZfP. Das DAfStb Heft 422 (1991) - Prufung von Beton Empfehlungen und Hinweise zu DIN 1048 - enthielt die Potentialfeldmessung bzw. das Merkblatt B3 im Anhang. In Deutschland liegen somit zwei Jahrzehnte Erfahrungen mit den entsprechenden Regelwerken und naturlich auch in der praktischen Anwendung vor. In der Praxis zeigte sich jedoch auch, dass die Anwendung verbessert werden muss. Die Potentialmessung wurde vielfach sogar falsch durchgefuhrt, ...
Purpose: An animal model is used to investigate whether MR angiography combined with super-paramagnetic particles of iron oxide (SPIO) is suitable for detecting thromboses. Methods: 42 rats in groups of 7 each were examined on days 1, 3, 5, 7, 9 and 11, respectively, after mechanical/chemical thrombus induction in a 1.5 Tesla magnet with a FISP sequence (TR/TE/FA 50 ms/6 ms/40 ). Imaging was performed before and up to 90 minutes after intravenous injection of 30 {mu}mol FE/kg BW of the experimental SPIO (hydrodynamic diameter, 34{+-}17 nm LLS; R1 and R2 relaxivity at 0.47 T, 31 and 57 L/(mmol*s)). MIP reconstructions of MR angiographies were submitted to consensus assessment by two examiners using histology as the gold standard. Results: The image quality of MIP reconstructions was rated as good in 38 of 42 cases. With regard to thrombotic vessel occlusion, MR angiography coincided with histology in 17 of 42 cases and differed in 25, lumen narrowing being overestimated by MRI in 4 ...
The typical MRI features of the most common pancreatic diseases, such as pancreatitis and adenocarcinoma of the pancreas, have been established. However, even in these common pancreatic disorders, MRI correlation with the underlying pathology is limited for clinical reasons. We emphasize MR-pathological correlation of inflammatory and neoplastic pancreatic changes, including pancreatitis, adenocarcinoma, acinar cell carcinoma, rare cystic and solid pancreatic neoplasms, and islet cell tumors. By highlighting the correlation of key pathological features with MR findings, a better understanding of the MR appearance of pancreatic pathology can be provided. In addition, MRI may prove a powerful tool in detection and characterization of pancreatic tumors. (orig.) [Deutsch] Das MR-tomographische Erscheinungsbild von Pankreatitiden und Adenokarzinomen des Pankreas, als den haeufigsten Pankreaserkrankungen, ist zwar ausreichend bekannt; allerdings ist selbst bei diesen ...
Present day mammography has not been able to make use of the advantages of digital luminescence radiography because of the limited spatial resolution. The recent development of electromagnetic focusing X-ray tube with effective focal spot sizes from 0.04 to 0.12 mm allows radiographic direct magnification with less geometric blur. It is now possible to combine direct magnification mammography with digital luminescence radiography. By combining high quality storage phosphor screens with an HQ-workstation a spatial resolution of 8 lp/mm is possible for 1.7-fold magnification. For 4-fold spot magnification views spatial resolution can be theoretically increased to approx. 20 lp/mm. One important advantage of digital radiography is the possibility of image-postprocessing. This article presents two sets of standard parameters and three sets of image dependent parameters for better imaging of specific lesions, such as microcalcifications. The introduction of the storage phosphor screen ...
Evaluation and interpretation of CT colonography is based on both 2D and 3D techniques. The 2D techniques are popular mainly because the time needed for evaluation is short. The 3D techniques allow better definition than the 2D techniques, especially of polyps close to folds or at the base of a fold. The evaluation strategies generally accepted so far (primarily 2D, with 3D for problem cases, or vice versa) demand knowledge of both 2D and 3D techniques. Newer 3D visualization techniques help make it possible to acquire more complete and faster recording particularly of areas that are not easily accessible to endoscopic examination. These user-friendly developments are thus well suited to improving the detection and the security of detection of polyps. It must be remembered that experience and the knowledge of associated artifacts and the limitations they can impose on diagnosis are prime requirements for the implementation of such visualization techniques. (orig.) [German] Die ...
The staging of patients with multiple myeloma demands sensitive imaging methods for the assessment of the skeletal system. MRI allows for direct visualization of the bone marrow which exhibits five different infiltration patterns in multiple myeloma: 1. normal appearance of the bone marrow, 2. focal involvement, 3. homogeneous diffuse infiltration, 4. combined diffuse and focal infiltration, 5. ''salt and pepper'' pattern with inhomogeneous bone marrow signals due to multiple fat islands. The combination of T1w-SE and STIR sequences is best suited for detecting all infiltration patterns and for the differential diagnoses e. g. hemangiomas. With parallel imaging in MRI, acquisition times can be markedly reduced and whole-body screening of the bone marrow can be achieved within 30 min. MRI is superior to radiography for the detection of focal as well as diffuse infiltration. Multidetector computed tomography and especially 16- and 64-detector row ...
Purpose: To evaluate a T{sub 2}-weighted URSE sequence for the assessment of pulmonary infiltrations in comparison to CT. Methods: 28 MRT scans of 22 patients with confirmed pneumonia were recorded on a 1.5 Tesla apparatus with an expiratory and diastolic triggered, T{sub 2}-weighted ultrafast-spin-echo sequence in axial slice mode with the following parameters: TR{sub eff}/T{sub E}/Turbofactor 2000-4000/90 ms/21-23; slice thickness/separation 6/0.6 mm; FOV 360 mm; 24 slices. 24 spiral CTs (sice thickness/table advance: 1-2 mm/10 mm) were available for comparison. The separate evaluation of MRTs and CTs was performed by three radiologists in a consensus procedure with regard to pulmonary lesions (e.g., infiltration, round foci, net patterns) and image quality of the MRTs (4-step scale). Results: In 71% of the cases the CTs and MRTs agreed with the diagnosis and representation of the lesions, in 25% MRT was superior. MRT was better for the detection of pulmonary abscesses. In 93% the ...
To compare the accuracy in the detection and staging of various malignant tumors with high resolution whole-body MRI using parallel imaging with whole-body dual-modality PET-CT. Preliminary results of an interim analysis from a prospective, blinded study are presented, in which 20 patients (mean age 59 years, range 27-77 years) with different oncological diseases underwent whole-body dual modality FDG-PET-CT screening for tumor search or staging in case of confirmed or suspected metastatic disease. All patients also underwent whole-body MRI imaging with the use of parallel imaging (iPAT). High-resolution coronal T1w- and STIR-sequences of 5 body levels with 512 x 512 matrix, axial fast T2w imaging of lung and abdomen (HASTE), contrast-enhanced dynamic and static T1w-sequences of liver, brain, abdomen, and pelvis were performed. Using a 32-channel whole-body MRI scanner (Magnetom Avanto, Siemens Medical Solutions) with a total field of view of 205 cm and free table movement, all ...
Purpose: To report the detection of con-compacted ventricular myocardium (NVCM) with MRI compared to echocardiography in 8 patients. Material and methods: Non-compaction of the ventricular myocardium is a congenital disorder characterized by an altered structure of the myocardial wall resulting from an intrauterine arrest in endomyocardial embryogenesis. The morphological findings consist of a prominent meshwork of multiple myocardial trabeculations and deep intertrabecular recesses, communicating with the left ventricular cavity. 8 consecutive patients (mean age 7.3 years) with clinical and echocardiographic signs of NCVM were examined by MRI (1.5 T, Vision, Siemens) in short axis and 2- and 4-chamber views, using T{sub 1}-weighted TSE and Cine-GRE in 6 patients and true FISP sequences in 2 patients. MRI and echocardiography were evaluated for visibility, signs of NCVM and involvement of myocardial wall segments. Thickness was measured for non-compacted and compacted myocardium and ...
This article describes the processes for the treatment of plastic waste: sampling, sorting, comminution. The requirements for the different processes for waste treatment (as recycling, utilization as raw material, energy recovery, combustion) are listed. (SR)
Fundamental investigations into the biosorption of environmentally relevant heavy metals were carried out with different microbial adsorbents, and processes were proposed for industrial effluents. In order to improve the technology of biosorption processes, attempts were made to improve the sorption efficiency of biological sorbents, and investigations were carried out on the immobilisation of biological adsorbents. (orig.) [Deutsch] Es wurden Grundlagenuntersuchungen zur Biosorption von umweltrelevanten Schwermetallen mit verschiedenen mikrobiellen Adsorbentien durchgefuehrt und an technischen Abwaessern Technologievorschlaege erarbeitet. Zur Verbesserung der Technologie von Biosorptionsprozessen wurden Moeglichkeiten der Steigerung der Sorptionsleistung von Biosorbentien erarbeitet und Untersuchungen zur Immobilisierung der biologischen Adsorbentien ...
A programme to optimize the short-term operation planning of hydrothermal system scheduling is presented. Based on heuristics, an operational planning of pumped storage plants and a method for fast evaluations of spot market deals under consideration of load forecast errors was developed. (orig.) [German] Vorgestellt wird ein Programm, das - basierend auf Heuristiken - den kurzfristigen Einsatz eines hydrothermischen Kraftwerksparks optimiert. Im Programm wurde dazu ein Verfahren zur Pumpseichereinsatzplanung und zur sekundenschnellen Bewertung von Spot-Markt-Geschaeften unter Beruecksichtigung von Lastprognosefehlern entwickelt. (orig.)
Zusammenfassung Das Konzept der ?quivalenten Spannung (Vergleichsspannung) wird seit langem angewendet und hat sich bew?hrt. Ein wesentlicher Grund daf?r liegt darin, dass es u.?a. bei der Formulierung ph?nomenologischer Werkstoffmodelle weiterhilft. Von Nachteil ist, dass es weder mit physikalischen Prinzipien in Verbindung steht, noch Informationen ?ber die Mikrostruktur des Werkstoffs enth?lt. Trotzdem wurden zahlreiche Hypothesen zur Formulierung von ?quivalenten Spannungen in der Vergangenheit aufgestellt und in der Praxis mit unterschiedlichem Erfolg angewendet. Als Basis f?r die Systematisierung der zahlreichen Modelle hat Yu die Unified Strength Theory (UST) vorgeschlagen. Diese eignet sich, u.?a. inkompressibles inelastisches Materialverhalten sowie kompressible Werkstoffe mit unt...
Automatic ultrasonic testing is presented as a method for recurrent inspections of pressure gas vessels, from validation to practical testing to customised test applications. National and international regulations and standards are presented along with related implementation problems. [German] Es wird die automatisierte Ultraschallpruefung im Bereich der wiederkehrenden Pruefung von Druckgasbehaeltern, als Alternative zur herkoemmlichen, klassischen Wasserdruckpruefung, vorgestellt. Von der Validierung ueber die praktische Erprobung bis hin zur kundenspezifisch entwickelten Pruefapplikation. Es werden die Anforderungen aus nationalen und internationalen Vorschriften und Normen sowie die damit zusammenhaengenden Umsetzungsprobleme behandelt.
Pyrolysis and combustion of CH are investigated. In order to reduce the work required for the present combination of parameters, the following substances were selected: Hexachloroethane, hexachlorocyclohexane, hexachlorobenzene and hexachlorophene. The model substances were pyrolyzed or combusted in varying conditions, and the combustion or pyrolysis products were analyzed. Only the main products were of interest; trace components are important only as far as they may throw light on the reaction mechanisms. The furnace design resulted in incomplete combustion and pyrolysis reactions, so that products of all stages of combusition or pyrolysis were available for analysis. Reaction processes can be derived from the products. As an alternative to thermal treatment of refuse, biological degradation of chlorinated hydrocarbons was gone into. The efficiency of decomposition by microorganisms was to be compared with the efficiency of thermal destruction of chlorohydrocarbons. The ...
Biosorption behaviour of and toxic effects of heavy metals in submersed and immobilised microorganisms was studied in batches and in continuous processes in an airlift-recycle reactor. Nickel, cadmium, and zinc were used as heavy metals. (orig./VHE) [Deutsch] Am Beispiel einer Naphthalin-2-sulfonsaeure-abbauenden Kultur wurde das Biosorptionsverhalten und die toxische Wirkung von Schwermetallen auf submerse und immobilisierte Mikroorganismen im Batch-Ansatz und im kontinuierlichen Betrieb in einem Airlift-Schlaufenreaktor untersucht. Als Schwermetalle wurden Nickel, Cadmium und Zink eingesetzt. (orig./VHE)
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 Definitionen 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.)
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.)
A report is given of investigations into the possibility of utilizing red mud from the Bayer process for producing Ferrari cements. On repeated burning at 1450deg C suitable mixtures of red mud with silica and lime form a clinker with a low free lime content from which Ferrari cement can be produced. The average 28-day compressive strengths of cements produced from this clinker are so encouraging that further investigations are appropriate. (orig.).
A new procedure for an efficient and sparing cleaning procedure of turbines was developed. The procedure uses cleaning and passivation chemicals that solve effectively and homogeneously salt and ferrous oxide coatings from turbines, avoiding attacks from corrosion, plugging and unbalances. In several high-pressure and condensation turbines the cleaning procedure has been already put into practice. (orig.)
Old banknotes may be tomorrow's biomass. Experts on biowaste are investigating two new processes for disposal of the 1000 tonnes of old bills sorted out every year which may be an alternative to combustion. The author presents details.
This bibliographical study compiles and analyzes findings about the metabolism and resorption of molybdenum. Besides including studies on the physiology of molybdenum 99, a general survey is given on molybdenum in the environment and on its physiological behaviour. In particular, information on the dependence of molybdenum resorption on various factors, such as the chemical form, antagonisms etc., are gathered from literature. These factors have to be considered for sensibly carrying out necessary experiments.
Faserbewehrter Beton wird heute zunehmend auch bei Tunnelbauwerken (Tunnelinnenschalen, Tubbinge) eingesetzt. Wesentliche Vorteile sind das hohe Tragvermogen, das daraus entstehende Einsparungspotential an herkommlicher stabformiger Bewehrung (Biegebewehrung, Bugelbewehrung in der Randzone), die Aufnahme von Spaltzugbeanspruchungen durch die Fasern, Rissbreitenbegrenzung, erhohte Dauerhaftigkeit, verbesserter Brandwiderstand (insbesondere bei Verwendung von Kunststofffasern), Optimierung der Arbeitsablaufe etc. Neue Entwicklungen in der Betontechnologie haben in den letzten Jahrzehnten den faserbewehrten ultrahochfesten Beton (engl. UHPFRC - Ultra High Performance Fibre Reinforced Concrete) hervorgebracht. Im Rahmen dieser Arbeit wird der Einsatz des ultrahochfesten, stahlfaserbewehrten Be...
The programme 'Solarthermie 2000' aimed at the testing and optimization of active solar systems, especially for service water heating. Sub-programme 2 was to provide the technical fundamentals and achieve a certain degree of standardization in order to make the technology economically competitive. This necessitated long-term monitoring of a representative number of systems. [German] Im Rahmen des Foerder- und Demonstrationsprogramms Solarthermie 2000, Teilprogramm 2 erfolgt durch die Foerderung von bis zu 100 solarthermischer Anlagen mit Schwerpunkt in den neuen Bundeslaendern eine umfassende Erprobung und Optimierung von Systemen zur aktiven thermischen Sonnenenergienutzung vorwiegend zur Brauchwassererwaermung. Mit dem Teilprogramm 2 sollen die technischen Voraussetzungen fuer einen kuenftigen wirksamen Beitrag der Solarthermie zur Energieversorgung geschaffen ...
Meltdown and gasification of waste in an oxygen atmosphere ('2sv' process) is an economically efficient alternative to energetic and thermal utilisation of biomass. Organic pollutants are split at temperatures up to 2000 C in a reducing atmosphere. The process uses elements of the oxygen cupola furnace for melting and gasification of many different waste fractions, e.g. polluted waste wood, household refuse and bulk waste, old tyres, light shredder fractions, sewage sludge, etc. [German] Die Sauerstoff-Schmelz-Vergasung ('2sv') stellt eine wirtschaftliche Alternative zur energetischen Nutzung von Biomassen wie auch zur thermischen Abfallverwertung dar. Organische Schadstoffe werden bei diesem neuen Verfahren bei Temperaturen bis zu 2000 C unter reduzierenden Bedingungen aufgespalten. Das Verfahren nutzt Elemente des Sauerstoff-Kupolofens fuer die Schmelzvergasung und eignet sich fuer ...
The RCP method was designed as a residue-optimised alternative to the thermally optimised grate firing of residual wastes. Its technical realisation and development to market maturity took no more than 5 years. In the first process stage the waste is converted to high-carbon pyrolysis charcoal and high-rank gas in the absence of oxygen. In the second stage these substances are oxidised by addition of oxygen. The resulting temperature causes the non-combustible constituents of the slag to melt. In a third, optional, stage this molten slag can be liberated of (heavy) metals to such an extent that it can subsequently be used directly as additive for grinding. Further exhaust gas treatment is facilitated by the use of a circulatory fluidised-bed secondary combustion chamber. Despite the reduced flue gas volume and resultant higher pollutant concentrations in the crude gas, overall emissions are lower than in conventional plants. [Deutsch] Das reststoffoptimierte RCP Verfahren ist als ...
A high-temperature flow reactor and different technical plants were tested within the framework of this research project. Anthropogenic N{sub 2}O emissions form during secondary flue gas or waste gas purification as secondary emissions during denitrification and pollution abatement measures. N{sub 2}O forms as an intermediate product as NO is reduced to N{sub 2}. Under certain operating conditions N{sub 2}O is not decomposed completely. Different secondary flue gas purification measures, i.e. selective noncatalytic reduction (SNCR), selective catalytic reduction (SCR), and nonselective catalytic reduction (NSCR) were investigated testing several technical plants and the high-temperature flow reactor. (orig./EF) [Deutsch] Das Forschungsprojekt ``Messung der N{sub 2}O-Emissionen von Verbrennungsanlagen und Untersuchung von Moeglichkeiten zur Emissionsminderung`` wurde an einem Hochtemperatur-Stroemungsreaktor und an ...
Flow Tex and ABB Energiekabel GmbH have developed a technique which allows the recovery of cables without requiring any trenching works. The new technique was successfully used for the first time for a pilot project in 1995. The authors report on two recent recovery projects (1998) in which an optimised technology was used for recovering a total of 1 500 m system length of 110 kV low-pressure oil-filled cables in Stuttgart and Munich on very different conditions. The authors describe the operational experiences with the cable connections and highlight the background stipulating the removal of the cables. (orig.) [Deutsch] Ein Verfahren zur grabungsfreien Bergung von Kabeln, gemeinsam entwickelt von FlowTex und ABB Energiekabel, wurde erstmals in einem Pilotprojekt 1995 mit Erfolg eingesetzt. Die Verfasser berichten ueber zwei Bergungsprojekte, bei denen 1998 mit der optimierten Technik in Stuttgart und Muenchen insgesamt 1 ...
The microelectronic cable diagnosis is a substantial tool to determine destruction free the residual strength and the lifetime of laid PE/XLPE medium voltage cables. Fundamentals of the ageing diagnosis and a cost reduced inspection concept are the `Isothermal-Relaxation-Current` Analysis and the Neuro-Fuzzy evaluation software. These new tools are able to determine the ageing status of the investigated cable without any references. The authors also show that the test breakdown during the assessment of the ageing status of criterial systems can be reduced by this approach. The cable diagnosis equipment KDA is also useful for the steering of investment as well as for preventive maintenance. (orig.) [Deutsch] Die zerstoerungsfreie dielektrische Kabeldiagnostik kann heute einen wesentlichen Beitrag zur Bestimmung der Restfestigkeit und der Restlebensdauer eines PE/VPE-isolierten Mittelspannungskabels leisten. Basis der Alterungsdiagnose und des Konzeptes ...
1. Cyanide degradation: Of the cyanide- and thiocyanate-degrading bacteria, Burkholderia cepacia and Pseudomonas spec. were the most effective. 2. Biosorption: Of the isolates suited for biosorption of heavy metals, 597-A (non-identifiable) and 597-A2 (Aspergillus fumigatis) had the biggest potential. The sorption capacity of the fungi for metals varied with the C source used for their growth: apple juice > molasses > glucose. The fungi are not cyanide-sensitive and can even degrade cyanide. Living biomass had better metal sorption efficiencies than dead mycelium. The biosorption rates in waste water were usually higher than in broth. Depending on the metal composition and concentrations and on the exposure time and volume of the mycelia, up to 85 % of the initial concentration was removed from the liquid phase. The capacity of different biomasses for the sorption of metal mixtures was between 65 and 80 mg/g of dry matter depending on the experimental conditions, with ...
Disposal of fine-particled byproducts via injection into a capola furnace using natural gas/O{sub 2} burners is a cost-efficient alternative to landfill dumping. Tests conducted in a foundry demonstrated that dusts collected there can be injected without detriment to melt-down rate and iron quality. The replacement of FeSi pellets with FeSi dust in addition reduced the slag content, while injection of coal dust permitted a decrease in coke consumption. (orig.) [Deutsch] Die Entsorgung von feinkoernigen Reststoffen durch Einblasen in einen Kupolofen ueber Erdgas/O{sub 2}-Brenner ist eine wirtschaftliche Alternative zur Deponierung. Anhand von Versuchen in einer Giesserei konnte aufgezeigt werden, dass hier anfallende Staeube ohne nachteilige Auswirkungen auf Schmelzleistung und Eisenqualitaet einzublasen sind. Die Substitution von FeSi-Formlingen durch FeSi-Staub brachte zudem eine Reduzierung des ...
A process model is presented and used for identifying options for controlling the cupola furnace process and for investigating natural gas substitutes. Fuel substitution will affect temperature curves (i.e. tapping temperatures and melting capacity), outlet temperatures and gas mass flow out of the preheating zone. The contribution presents several process variations to overcome these problems and compares them with the natural gas process. [German] Mit dem Prozessmodell werden zunaechst Moeglichkeiten der Steuerung von Abstichtemperatur und Schmelzleistung, insbesondere unter Beruecksichtigung der Schrottqualitaet (spezifische Oberflaeche a{sub G}), untersucht. Es wird gezeigt, dass das Prozessmodell die Ergebnisse aus der Praxis wiedergibt. Daran anschliessend wird mit dem Prozessmodell die Substitution von Erdgas durch minderwertige Gase untersucht (Brennstoffsubstitution, Ressourcenschonung). Durch die Brennstoffsubstitution veraendern sich ...
Experts tend to disagree about the economic effects of air pollution abatement measures. This book, which addresses also non-experts, explains the analytical background on the basis of available data. The authors conclude that there is a wide range of political options for achieving the goal of air pollution abatement. They differentiate between the various levels of discussion and show how misinterpretations of scientific results come about, thus making an important contribution to a discussion that is based on facts rather than emotions. [German] Die Einschaetzungen zur wirtschaftlichen Bewertung von Klimaschutzmassnahmen, insbesondere zur Steigerung der Energieeffizienz, sind sehr widerspruechlich. Dieses Buch erlaeutert anhand von Zahlenmaterial die analytischen Hintergruende und ist auch fuer Nicht-Oekonomen verstaendlich geschrieben. Die Autoren kommen zu dem Schluss, dass in vielen Bereichen ...
For millions of people general noise and especially traffic noise are the main sources of environmental pollution. The increasingly stricter noise pollution abatement limiting values laid down by the law call for motor vehicle noise pollution abatement measures. Within the framework of today`s cost- and performance-oriented automobile and engine development developing engineers are required to reduce noise levels. The present state of the art is described and future possibilities of combustion engine structure-borne noise calculation and optimization are discussed from the point of view of K + P Computerunterstuetzte Strukturanalysen GmbH. (orig.) [Deutsch] Laerm allgemein und dabei speziell wiederum der Verkehrslaerm steht fuer Millionen von Menschen an allererster Stelle der persoenlichen Belastung durch die Umwelt. Zur Minderung der Laermbelastung werden vom Gesetzgeber immer schaerfere Grenzwerte vorgeschrieben, die dazu zwingen, Massnahmen ...
To evaluate the current situation and implementation of embolization of uterine leiomyomas into the treatment concept in women with symptomatic uterine leiomyomas in Germany. A questionnaire addressing the clinical background of uterine myomas, recommended treatment concepts, preclinical evaluation, technical approach and complications was sent to 164 departments of gynecology and radiology in Germany. 33 radiological departments and 19 gynecological departments submitted a completed questionnaire. Only 7 departments of radiology reported to have own experience with embolization of uterine leiomyomas, while only 2 departments of gynecology considered embolization as an alternative treatment option in patients with symptomatic leiomyomas. 18/33 radiological departments offer this treatment option but get no patient referrals. Agreement was found concerning the indications for treatment, preclinical evaluation by ultrasound and MRI, preferable location of treatable fibroids, technical ...
This is a process for the manufacture of a filter material for cleaning industrial or internal combustion engine exhaust gases and filter material manufactured according to the process. The filter material is manufactured from the mineralized combustion product of peel of tropical fruits burnt at a temperature of 820/sup 0/C to 840/sup 0/C in an oxidising atmosphere excluding the production of carbon, particularly using banana skins and orange peels, which product is granulated with carrier materials or compressed.
In Duisburg the Citibank is building a new call center. As an alternative to the conventional switch cupboard technology, an innovative energy bus technology by ABB Gebaeudeautomation is being used: it involves less planning effort, faster start of operation and a shorter construction time, cost saving through lower space and material demand, plus the advantage of flexibility of extension. (orig.) [German] In Duisburg entsteht zur Zeit der Neubau eines Call Centers der Citibank. Dabei wird als Alternative zur herkoemmlichen Schaltschranktechnik die innovative Energiebus-Technik von ABB Gebaeudeautomation eingesetzt: Geringerer Planungsaufwand, schnellere Inbetriebnahme und kurze Bauzeit, Kostenersparnis durch geringeren Platz- und Materialverbrauch sowie flexible Erweiterbarkeit sind die Vorteile. (orig.)
This publication contains the Ordinance on Heating Costs, the Ordinance on Heating Installations, and the 1st Federal Ordinance on Emission Control (BImSchV) concerning Small-Scale Furnaces, in each case with notes and explanations. All these ordinances aim at reducing energy consumption in connection with heating; the 1st BImSchV also at air pollution abatement by lowering the permissible limiting values for soot and flue gas. The three ordinances also apply to housing property. (HSCH).
The stirling cryocooler ILK 15 is a machine with simple drive concept. This machine works with a conventional built-in electric motor and crank drive and needs a power input of about 500 W. The refrigerating capacity is 15 W at 80 K with a cooldown time of 12 minutes. The cooler is somehow a replacement for the Gifford-McMahon cycle coolers, which are bigger and heavier. The Stirling cryocooler was designed to cool HTSC-components. (orig.) [Deutsch] Der Stirlingkuehler ILK 15 ist eine Kaeltemaschine mit einfachem Antriebskonzept. Die Maschine arbeitet mit einem konventionellen Elektroeinbaumotor und Kurbeltrieb. Sie benoetigt eine Antriebsleistung von 500 W und hat eine Kaelteleistung von 15 W bis 80 K und eine Einkuehlzeit von 12 Minuten. Die Maschine kann als Alternative zur wesentlich groesseren und schweren Gifford-McMahon-Maschine gesehen und bei der Kuehlung von ...
Under the new name of ``geothermal heat pump``, ground-source heat pumps are currently high in demand in Northern America. In sectors characterized by heating and cold air demand, their advantages can be exploited to the full. For Germany, the end-use-energy substitution potential of geothermal heat pumps has been estimated at 1310-1470 PJ annually. Whether this potential can actually be exploited depends essentially on the development of energy prices, but also on the resourcefulness of plant and heat pump manufacturers in upgrading and cheapening geothermal heat pumps. (orig./RHM) [Deutsch] Unter der neuen Bezeichnung `Geothermal Heat Pump` erlebt die erdgekoppelte Waermepumpe z.Zt. in Nordamerika einen Verbreitungsschub. In dem durch Heiz- und Kuehlbedarf charakterisierten Umfeld kann sie Ihre Vorteile voll nutzen. Fuer Deutschland kommt eine Schaetzung zu einem Potential der erdgekoppelten Waermepumpen zur Substition von Endenergie ...
Calcium sulfate dihydrate which is co-produced in the scrubbing of waste gases from bituminous coal power plants is employed in the underground road securing after recrystallization. Beta-sulfate semi hydrate is obtained from the dihydrate by recrystallisation and it is used as such or as a stiff mixture with additives as a stowing material. Particularly fly ash from coal combustion units, washery refuses and development rocks from coal mining or slags from the metallurgical industry can be used as additives. The compressive and the bending tensile strength of the stowing material can be adjusted by the water content in case beta sulfate semihydrate is used as such.
This is a process for producing calcium sulfate dihydrate during desulfurization of stack gases from power station boilers, where the stack gases are introduced into a washing tower and are treated with a washing water suspension containing lime in the washing tower, where oxygen in the form of air or of air enriched in oxygen is also blown into the washing tower, and where the washing water suspension drawn off from the washing tower is fed back to the washing tower at a temperature of 45 to 50/sup 0/C in the circuit and at least part of the flow goes via a thickener and where calcium sulfate dihydrate slurry is drawn off from the thickener.
This conference of Deutsche Wissenschaftliche Gesellschaft fuer Erdoel, Erdgas und Kohle focused on energetic utilisation and recycling of waste materials and biomass, i.e. combustion, gasification and pyrolysis. Aspects of process control were gone into as well. [German] Die Fachbereichstagung der Deutschen Wissenschaftlichen Gesellschaft fuer Erdoel, Erdgas und Kohle beschaeftigte sich mit der energetischen und stofflichen Nutzung von Abfall und Biomasse. Verbrennung, Vergasung und Pyrolyse verschiedener Abfallstoffe sowie die Prozesssteuerung wurden eroertert.
The research project aimed at the selection or development of wear-reducing measures for submerged components of hydroelectric power plants. This comprised the optimisation of hydraulic profiles as well as materials testing for abrasion and cavitation. Another field of research was the development of appropriate application processes. (orig.) [German] Das Hauptziel des Forschungsvorhabens bestand in der Auswahl bzw. Entwicklung geeigneter Schutzmassnahmen zur Verschleissminderung an wasserberuehrten Komponenten von Wasserkraftanlagen. Diesem Ziel untergeordnet waren neben der Optimierung hydraulischer Profile auch Materialuntersuchungen hinsichtlich Verschleissbestaendigkeit gegenueber Abrasion und Kavitation. Ebenso war die Entwicklung geeigneter Applikationsprozesse ein wichtiger Bestandteil der Aufgabenstellung. (orig.)
The author investigates whether waste fermentation is an economically feasible alternative to composting. Decisions on projects and sites should not be made until the basic problems of feasibility and economic efficiency are solved. [German] In Anbetracht der derzeitigen Situation bei der Restmuellbehandlung, in der die mechanisch-biologische Behandlung als Alternative zu einer rein thermischen Behandlung immer mehr an Bedeutung gewinnt, stellt sich immer haeufiger die Frage, ob die Restmuellvergaerung eine Alternative zur ausschliesslichen Restmuellrotte darstellt. Diese Frage muss zunaechst prinzipiell aus Sicht der technischen Machbarkeit und von der Sinnhaftigkeit, hier vor allem von der Kostenseite her, betrachtet werden. Erst daran anschliessend lassen sich projekt- und standortbezogene Betrachtungen anstellen. Hinsichtlich der technischen Machbarkeit laesst sich im wesentlichen auf den grosstechnischen Erfahrungen ...
Purpose: calculation of conversion coefficients for the reconstruction of organ doses from entrance doses for abdomen radiographs of 0, 1, 5, 10, 15, and 30-year-old patients in conventional pediatric radiology for the radiographic settings recommended by the German and European guidelines for quality management in diagnostic radiology. Materials und method: using the commercially available personal computer program PCXMC developed by the Finnish Center for Radiation and Nuclear Safety (Saeteilyturvakeskus STUK), conversion coefficients for conventional abdomen radiographs were calculated performing Monte Carlo simulations in mathematical hermaphrodite phantom models describing patients of different ages. The possible clinical variation of beam collimation was taken into consideration by defining optimal and suboptimal radiation fields on the phantoms' surfaces. Results: conversion coefficients for the reconstruction of organ does in about 40 organs and tissues of the human ...
Modern oscillation- and analysis systems are often mentioned in the context of oscillation diagnosis which implies that this is a method of establishing the causes of the mechanical changes that cause the unwanted oscillation. Experience shows, however, that oscillation monitoring instruments can merely indicate oscillation symptoms at an early point in time. These findings must be interpreted in a machine-specific way and seen in the context of previous developments in order to establish the mechanical root cause of the matter. A 1000 MVA-generator shows that conventional oscillation measuring systems may also serve for diagnostic purposes within certain limits.(orig.) [German] Im Zusammenhang mit modernen Schwingungsmess- und Analysensystemen wird haeufig der Begriff der Schwingungsdiagnose verwandt und inpliziert, damit auch die Ursache von mechanischen Veraenderungen finden zu koennen, welche das beanstandete Schwingungsverhalten hervorruft. In der Praxis zeigt ...
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)
In the last two years, the VDMA work group 'Functional security' compiled a qualitative and quantitative procedure for the determination and evaluation of turbo-machine specific risks. With the calibrated risk graph for turbo-machines the requirements (Safety Integrity Level SIL) to the protective functions for turbo-machines (steam turbines, gas turbines, generators and compressors) were determined. With consideration of the legislation, the work group compiled a recommendation for the renewal and/or reconstruction of protective functions with old facilities.
In order to improve the capacity and service life of cathodes, the effect of carboxy-methyl cellulose, soot, silica gel and fibres was examined. Structural tests and electrical and electro-chemical measurements are used for this. The additives can affect crystallization in the manufacturing stage of the electrodes and can increase the storage capacity for water and the electronic conductivity. They act to stabilize the mass in cyclic operation. Soot additive has little effect on the properties of the electrode, but the other substances increase the service life or the use of the mass. (LU).
In recent years very good experience has been accumulated with self-supporting low-pressure blades. Today blades are constructed up to a length of 1060 mm (50 Hz) or 1360 mm (25 Hz). In this process modern computational methods from aerodynamics and also from mechanics are employed. The further development of computer technology also permits new methods, for example the use of curved fixed blading as well as the optimization of existing designs. (orig.).
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 ...
The first biogas plant using the Plauen method has been operated without failures in the Saxon Vogtland since May 1987. This large scale anaerob treatment plant which is the first one in Germany handles besides agricultural recidual substance both municipal and industrial organic residues. The results show clearly that fermentation is a real alternative to composting, combusting and deponing. (orig.)
Within its competence for energy research, the Bundesministerium fuer Wirtschaft und Arbeit (BMWA) (Federal Ministry of Economics and Technology) sponsors investigations into the safety of nuclear power plants. The objective of these investigations is to provide fundamental knowledge, procedures and methods to contribute to realistic safety assessments of nuclear installations, to the further development of safety technology and to make use of the potential of innovative safety-related approaches. The Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) mbH, by order to the BMWi, continuously issues information on the status of such investigations by publishing semi-annual and annual progress reports within the series of GRS-F-Fortschrittsberichte (GRS-F-Progress Reports). Each progress report represents a compilation of individual reports about the objectives, work performed, results achieved, next steps of the work etc. The individual reports are prepared in a standard form by the ...
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 ...
Surface structure analysis, i.e. metallographic analysis of component surfaces with the aid of replicas, is an established method of component monitoring and the only reliable non-destructive method for detecting and analyzing beginning creep damage in the form of creep pores. Creep pore development provides a basis for component condition analysis. It must be noted, however, that the modern martensitic 9-12 % Cr steels - like the established steels 10CrMo9-10 (P22) und X20CrMoV12-1 - have comparatively high creep fracture deformation rates in fatigue tests. This raises the question if these steels can be judged on the basis of data for established steels. The results so far suggest that even with low pore densities (single pores), a higher degree of damage and a shorter time until failure must be assumed. [German] Eine bewaehrte Methode der Bauteilueberwachung stellt die Oberflaechengefuegeuntersuchung, d. h. die metallografische Untersuchung der Bauteiloberflaeche mit Hilfe ...
Economic and safe operation of nuclear power plants requires reliable steam turbines with high efficiencies. The progress in flow mechanics achieved over the past few years has allowed the use of powerful methods of flow calculation in developments of new blading with greatly enhanced efficiencies. Thanks to the latest manufacturing techniques, the newly developed blading systems can be produced at low cost. Next to progress in flow mechanics, also the broadbased use of advanced finite-element calculations resulted in a more thorough grasp of the many problems associated with structural mechanics assessment of steam turbine components. The theoretical methods have been supplemented by comprehensive efforts in fracture mechanics and experimental materials studies, thus helping to create a reliable knowledge base which will help to avoid the dreaded stress corrosion cracking phenomenon, in components of steam turbines. The measures introduced to improve operational reliability already in ...
The position paper will provide the basis for further strategies on offshore wind power development in consideration of ecological and conservation aspects. [German] Das Positionspapier des Bundesministeriums fuer Umwelt, Naturschutz und Reaktorsicherheit (BMU) einschliesslich des Umweltbundesamtes (UBA) und des Bundesamtes fuer Naturschutz (BfN) ist Ergebnis der Arbeiten der BMU-Projektgruppe 'Windenergienutzung im Offshore-Bereich im Hinblick auf die BMU-Anliegen'. Es beschreibt den derzeitigen Stand einer Strategie zur umwelt- und naturvertraeglichen Erschliessung der Windenergienutzung auf See (Offshore). Es bildet die Grundlage fuer die Weiterentwicklung dieser Strategie und dabei insbesondere zur Abstimmung mit den Anliegen anderer Bundesressorts und den Kuestenlaendern, sowie zur intensiveren Einbeziehung beteiligter Verbaende und Fachkreise. Vor dem Hintergrund der zur ...
TRITEX was a pumped loop with Pb-15.8Li, fabricated from steel 1.4922. In contact with the molten eutectic were also molybdenum, vanadium and armco-iron. The loop was originally designed to investigate tritium extraction using solid getter metals. Over the years the goal changed to the study of metals, corrosion products and purification of the eutectic mixture. Therefore many modifications were done. The first part of this report describes TRITEX. All parts were enclosed in thermoboxes for a homogeneous temperature. One test section was in an argon glove box and could be opened during operation. Other special equipment`s were: permeation membranes and liquid-metal-covergas-interfaces to study the transport of H{sub 2}, D{sub 2} and {sup 3}H, different purification devices, a quartz observation window to see the liquid metal surface, 4 different kinds of flow measurements, level indicators, freeze valves. The second part describes loop operation. Between 1989 and 1996, the eutectic ...
The first volume of the report covers the state of implementation of primary and secondary measures for SO{sub 2}- and NO{sub x} control applied in the most important industrial sectors in Germany. Integrated pollution abatement techniques, called primary measures in this report, such as process integrated measures and low emission processes, have gained increased importance in recent years. The end-of-pipe processes, described here as secondary measures, are generally highly effective. They represent mature technologies, which are capable of achieving significant reductions in SO{sub 2}- and NO{sub x} emissions, and which have been used in particular for retrofitting existing plants. At first, an overview is given regarding the development of SO{sub 2}- and NO{sub x} emissions in selected European countries during the last 20 years and in Europe. Current national and European emission limits and emission guidelines on SO{sub 2}- and NO{sub x} emissions from stationary sources are ...
The regenerator of Stirling cycle machines has an relatively unknown potential for thermal shorting, because the thermal flow path within the solid of a randomly stacked wire mesh, which is defined by its 'connectivity', is unknown. Earlier publications have shown two principles of experimental techniques to quantify connectivity. One quantifies connectivity as a function of axial pressure using the electric current analogy, the other measures connectivity via the temperature gradients along a regenerator and a series-connected reference body of known conductivity. Both papers offer preliminary results of reduced usefulness related to the testing method or setup. This contribution describes a new setup and its technique, which results from the practical knowledge and experience of the first two attempts, and aims for an improved determination of connectivity of the original representative Stirling regenerators with and without housing. Please contact the author for ...
This report presents the results of the BMBF-sponsored project Fundamentals and models for assessing the effect of climate changes on soil, plant development and the crops of an economically significant range of farm products. Its aim was to study, by means of the results obtained for winter wheat, the dependence of plant growth on temperature, radiation and water as well as nutrient supply for other economically important crop types. Building on this, process-oriented, climate-sensitive agricultural ecosystem models for winter rye, winter barley, sugar-beet and winter intercrops were developed, verified and, in some sites, validated. First scenario calculations served to demonstrate the climate sensitivity of these models. (orig./KW) [Deutsch] Im vorliegenden Bericht werden die Ergebnisse des BMBF - Vorhabens `Grundlagen und Modelle zur Abschaetzung von Klimaaenderungen auf den Boden, die Pflanzenentwicklung sowie den verwertbaren Ernteertrag ...
On February 20th 1998 Auckland, the biggest city of New Zealand, was nearly paralyzed by an extended power failure. On this day the last of four cables supplying the central business district failed and caused a five weeks lasting blackout. This failure has caused costs of 128.3 Mio NZ Dollar for the affected utility Mercury Energy Ltd. The official ministerial inquiry was published on July 21st 1998 and reproaches the utility in an unusual clear manner. (orig.) [Deutsch] Am 20. Februar 1998 wurde Auckland, die groesste Stadt Neuseelands, von einer folgenschweren Unterbrechung der Stromversorgung nahezu lahmgelegt. An diesem Tag fiel das letzte von vier 110-kV-Kabeln zur Versorgung des Innenstadtbereiches aus und verursachte damit einen 5 Wochen dauernden Stromausfall. Diese Versorgungsunterbrechung hat bisher Kosten in Hoehe von 128,3 Mio NZ Dollar (rd. 115,5 Mio DM) fuer den oertlichen Stromversorger ...
A computer program for optimization of modular cogeneration plants is introduced. Computer calculation fundamentals are discussed referring to examples which elucidate the verification of the calculated data by measured data or empirical values. The results obtained as one optimizes plants by varying their size or by splitting them into modules are introduced referring to examples. Sensitivity analyses are made to investigate the influence of parameters such as fuel prices, electricity tariffs and interest rates. (orig.) [Deutsch] Im vorliegenden Beitrag wird ein Computerprogramm zur Optimierung von BHKW-Anlagen vorgestellt. Zunaechst werden in einem ersten Schritt die Berechnungsgrundlagen an einem Beispiel in Hinblick auf ihre Ueberpruefung durch Messdaten oder durch Erfahrungswerte diskutiert. Dann werden in einem zweiten Schritt exemplarisch die Ergebnisse einer Optimierung durch Variation der Gesamtanlagengroesse auf Aufsplittung der ...
The report gives a brief introduction into the EU grant programmes since 1984 and explains the philosophy behind them. The current situation regarding grant opportunities for the construction and modernization of small hydroelectric installations is outlined. Hints are given with a view to grant applications. A selection of small hydro power stations supported by grants (since 1984) are described with their economic and technical features. (orig.) [Deutsch] In diesem Beitrag wird eine kurze Einfuehrung in die EU-Foerderprogramme seit 1984 und Erlaeuterungen zu der Programmphilosophie gegeben. Die derzeitige Situation bezueglich der Foerderung von Kleinwasserkraftanlagen fuer Neubauten und Modernisierungsmassnahmen wird dargestellt. Es werden Hinweise zur Stellung eines Foerderantrags beschrieben. Abschliessend erfolgt die Vorstellung einer Auswahl von gefoerderten Kleinwasserkraftanlagen (seit 1984) mit den wirtschaftlichen ...
T{sub 2} weighted ultra-short turbo spin echo sequences were used in five individuals with variations in echo times, delayed triggering and echo intervals. To reduce movement artifacts all examinations were carried out with ECG and respiratory triggering. The sequences giving optimal image quality were then employed in 19 patients having various pulmonary abnormalities. Image resolutions, artifacts, image contrasts and diagnostic value were then judged by two observers and compared with CT. In the first study, a diastole-triggered UTSE sequence with the shortest echo proved optimal (T{sub E}=90 ms, T{sub R}=2-4 s, echo=9 ms, turbo factor=19). In the patient series studied, MRT was inferior to CT with regard to resolution and number of artifacts, but better in respect of contrast and diagnostic value. Using UTSE of the lung, MRT can produce images of good quality. Compared with CT, contrast is better with MRT, offering diagnostic advantages for MRT. (orig./MG) [Deutsch] Zuerst wurde an ...
FLUTAN is a highly vectorized computer code for 3D fluiddynamic and thermal-hydraulic analyses in Cartesian or cylinder coordinates. It is related to the family of COMMIX codes originally developed at Argonne National Laboratory, USA, and particularly to COMMIX-1A and COMMIX-1B, which were made available to FZK in the frame of cooperation contracts within the fast reactor safety field. FLUTAN 2.0 is an improved version of the FLUTAN code released in 1992. It offers some additional innovations, e.g. the QUICK-LECUSSO-FRAM techniques for reducing numerical diffusion in the k-{epsilon} turbulence model equations; a higher sophisticated wall model for specifying a mass flow outside the surface walls together with its flow path and its associated inlet and outlet flow temperatures; and a revised and upgraded pressure boundary condition to fully include the outlet cells in the solution process of the conservation equations. Last but not least, a so-called visualization option based on VISART ...
CT-Expo is a novel MS Excel application for assessing the radiation doses delivered to patients undergoing CT examinations, based on computational methods that were used to analyze the data collected in the German survey on CT practice in 1999. The program enables the calculation of all dose quantities of practical value, such as axial dose free-in-air, weighted CTDI, dose-length product, effective dose and uterine dose. In contrast to existing programs for CT dose assessment, CT-Expo offers a number of unique features, such as gender-specific dose calculation for all age groups (adults, children, newborns), applicability to all existing scanner models including correction of scanner-specific influences, and the possibility of comparison with the results from the German CT survey on CT practice. Three different application modules offer free and standardized dose calculations as well as a comprehensive benchmarking section including guidance on dose optimization. The program is ...
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 ...
A part of the waste materials arising in iron and steel manufacture is utilised physically, either internally for the recovery of iron or externally for the production of cement and nonferrous metals. Most of these materials can be used without prior processing. Iron and steel-relevant waste materials which at present are still landfilled or disposed of as hazardous wastes are not immediately suitable for physical recycling as secondary raw material. These waste materials have to be processed without exception before they can be used again in the existing steel and iron manufacturing plants. The results of the authors` own studies have clearly shown that the cupola furnace is suited for the use of a wide variety of waste materials. [Deutsch] Ein Teil der bei der Eisen- und Stahlerzeugung anfallenden Abfallstoffe werden entweder intern zur Rueckgewinnung des Eisens oder extern in der Zement- bzw. Nichteisenmetallgewinnung stofflich verwertet. Dabei handelt es sich ...
Volatile organic compounds (VOC) are an important group of pollutants with adverse effects on humans and the environment. Primary air pollution abatement measures aim at prevention or reduction of pollutant production in industrial production processes, e.g. by improved processes but also by other methods (closed cycle processes, different process materials, etc.). If these measures have been implemented and emissions are still too high, an off-air purification unit must be installed. Biological purification is the method of choice for low pollutant concentrations. Biological purification processes are based on the activity of microorganisms which are capable of biochemical oxidation of organic and some inorganic gaseous compounds into non-polluting or non-odorous compounds. These processes have the advantage that they work at ambient conditions and therefore remove relatively low pollutant concentrations at low investment and operating cost. Lately, biological filters and washers have ...
Blades of modern steam turbines are designed for high efficiency and operational safety. Modern computer programs enable optimisation of design but factors like manufacturing, assembly, operation and downtimes still play an important role. Damage statistics show that blade damage still quite frequent. Selected cases from the Allianz damage assessment centre show some of the more frequent damage mechanisms. Damage is often caused when several factors come together. Prevention of follow-up damage requires early identification of beginning damage.(orig.) [German] Die Auslegung der Beschaufelung moderner Dampfturbinen hat die Vorgabe, einen hohen Wirkungsgrad bei gleichzeitig hoher Betriebssicherheit zu erreichen. Mit den heute zur Verfuegung stehenden Rechenprogrammen ist eine entsprechende Optimierung realisierbar. Fuer die langzeitige Betriebsbewaehrung haben aber Einflussgroessen aus Fertigung, Montage, Betrieb und Stillstand auch heute noch die gleiche Bedeutung ...
A procedure is described for the isolation and determination of {sup 90}Sr, {sup 226}Ra, {sup 228}Ra and {sup 210}Pb in food. These nuclides are highly radiotoxic, above all for babies and children. Samples are dry ashed, alkali metals are removed as carbonates. Separation from other matrix ions and separation of Ra, Sr and Pb can be achieved with a column of Sr-Spec, an immobilized crown ether. For activity measurements membrane filters with SrSO{sub 4}, Ba(Ra)SO{sub 4} and PbS are prepared. Ra is determined by gamma-spectrometry, {sup 90}Sr and {sup 210}Pb are determined by low-level-betacounting. The determination limits are 10 mBq/kg for {sup 90}Sr and {sup 210}Pb and 50 mBq/kg for {sup 226}Ra and {sup 228}Ra. The procedure is useful for all kinds of foodstuff. (orig.) [Deutsch] Es wird ein Analysengang zur Abtrennung und Bestimmung von {sup 90}Sr, {sup 226}Ra, {sup 228}Ra und {sup 210}Pb in Lebensmitteln beschrieben. Ein Merkmal dieser ...
In 1986, following comprehensive preliminary studies, a 17 MW battery energy storage plant was set up in the insular power supply system of Berlin (West) for the purpose of frequency and output control and provision of immediate reserve capacities. The present paper reports on the initial task, and the dimensioning and construction of this large-scale demonstration as well as the costs entailed in this. It also relates the experiences gained with the operation of the battery energy storage plant in its function as a fast-responding control unit and gives an account of its economic efficiency. Recent studies on the economic efficiency of the plant in conditions as they exist in the present interconnected power supply system are presented. Finally the author reports on the experiences gained with individual plant components, i.e., battery, battery periphery, and power converter and quantifies the cost of plant operation, maintenance, and servicing. (orig./HW) [Deutsch] Im Inselnetz ...
The VerTech Pit Method for wet oxidation of municipal sewage sludge offers an ecologically and economically advantageous alternative for dealing with sewage and special sludges. Europe`s first commercial plant has now been commissioned in Apeldoorn in the Netherlands following industrial-scale trials in the USA. Up to its present stage of operation the plant has achieved a high degree of reduction of solid residues and a favourable resource and environmental profile, thus impressively confirming earlier results. It is amply in keeping with the landfill criteria laid down in the Household Waste Technical Code. Furthermore, the potential sludge throughput has been found to exceed the projected value. [Deutsch] Mit dem VerTech-Tiefschachtverfahren zur Nassoxidation kommunaler Klaerschlaemme steht ein alternatives Verfahren zur Behandlung von Klaer- und Sonderschlaemmen zur Verfuegung, das oekologische und ...
A phenomenological model of the heat transfer in direct injection diesel engines was developed. Utilizing the thermodynamic results of a combustion model as an input, the model is able to predict the temporal variation of the heat losses from the cylinder gas to the cylinder walls. Additionally, the division into isothermal combustion chamber subsurfaces allows the consideration of the spatial variation of the wall heat fluxes. The physical mechanisms such as flow dependent convection, heat radiation due to hot soot particles and isolation effects of deposited soot layers are described in detail. Thus the effects of these mechanisms on the overall heat transfer can be studied. The heat transfer model was verified successfully by the comparison to measured wall heat fluxes in a single-cylinder direct injection diesel engine. It is shown that the effects of engine speed and load, turbocharging and soot deposition can be predicted with good accuracy. [German] Es wurde ein ...
The intermetallic phase NiAl is a potential material for high-temperature applications; however, its technical application was prevented so far by its high brittleness at room temperature. This problem may be solved by incorporating relatively high-ductility particles into the NiAl matrix. Controlled crack propagation experiments, tensile and pressure tests were carried out in order to analyze the toughness and deformation characteristics of NiAl composite materials containing niobium or molybdenum particles at room temperature and in ambient atmosphere. Both the niobium and the molybdenum particles increase the toughness as compared to the pure NiAl matrix, but no ductilisation was observed in the composite materials investigated. Model experiments in consideration of experimental data suggest, hovewer, that the toughness and ductility of NiAl may be enhanced by optimizing the microstructural and production parameters of the incorporated ductile particles. (orig.) [Deutsch] Die ...
Today electric power steering systems are regularly considered by the car manufacturers as an alternative to a conventional hydraulic power steering system in the development of new vehicle platforms. Simplified vehicle assembly and the potential to contribute to the reduction of the vehicle's energy consumption are the main motivation for this. The performance of the systems available at present with 13.5 V supply voltage will be improved even more as soon as the future 42 V vehicle electrical systems are available. Like most active chassis systems, electric power steering has to meet the highest safety requirements imaginable. This article summarizes the safety philosophy of the TRW rack drive Electric Power Steering system. (orig.) [German] Elektromechanische Servolenkungen werden heute bei der Entwicklung neuer Fahrzeuge als Alternative zur konventionellen hydraulischen Servolenkung in Betracht gezogen. Die vereinfachte Fahrzeugmontage und das ...
LP steam turbine retrofits are generally undertaken as a result of mechanical problems, for example due to stress corrosion cracking, torsional vibration or erosion. They present plant operators with an opportunity to introduce advanced aerodynamic technology, and at the same time improve efficiency and availability. Standard components, the majority proven in long-term service, can be used to obtain a permanent solution to the problems. In several European countries, retrofits have been carried out on intact LP steam turbines owned by utilities whose primary motivation is efficiency improvement. (orig.) [Deutsch] Niederdruck-Dampfturbinen werden in der Regel nur dann nachgeruestet, wenn waehrend des Betriebes Probleme durch Spannungsrisskorrosion, Torsionsschwingungen oder Erosion auftreten. In solchen Faellen bietet sich die Gelegenheit, eine moderne aerodynamische Loesung zu waehlen, die gleichzeitig Wirkungsgrad und Verfuegbarkeit verbessert. Es wird gezeigt, dass hierfuer eine ...
In the first part of the symposium, experts reviewed the state of the art of decentralized waste water treatment in Europe. In the second part, exemplary solutions in Poland and the Czech Republic were presented. The final part was dedicated to future concepts and strategies. [German] Im Herbst letzten Jahres hat die Kommunale Umwelt-AktioN U.A.N. in einer Abfolge von drei Abwasserfachsymposien Expertenrunden zum Austausch ueber den aktuellen Stand des Wissens zum Thema dezentrale Abwasserbehandlung veranstaltet. Mit dem Internationalen Symposium 'Konzepte zur Abwasserbehandlung im laendlichen Raum Europas' in Celle hat das Projekt der U.A.N. seinen Abschluss gefunden. Der Konzeption des Projektes entsprechend haben im 1. Teil des Symposiums Experten ueber den Stand der Entwicklung auf dem Sektor der dezentralen Abwasserbehandlung in Deutschland berichtet. Im 2. Teil unserer Fachtagung wurden europaeische Beispiele fuer ...
Basic research in relation to a complete utilisation of animal substances as an alternative to a thermal disposal was done. The composition of different kinds of bones were investigated as well as their amounts which are available. Conventional utilisation was opposed to the innovative utilisation. Technologies will be selected which should be developed, because they have the chance in the case of a fast industrial realisation to get a good profit. There is a global requirement for the technologies which are developed and their products which can be produced with this. The raw material basis is available in the necessary scale in nearly all countries. (orig.) [German] Grundlegende Untersuchungen zur ganzheitlichen Verwertung von tierischen Substanzen als Alternative zur thermischen Entsorgung wurden durchgefuehrt. Es wurde die Zusammensetzung der verschiedenen Knochenarten und ihr Aufkommen untersucht. Die konventionelle ...
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 ...
For the calculation of humidifier systems in supply air systems nomographs and appropriate software are not sufficient alone. System design factors must be considered, also. On the basis of a clear definition interpretation examples are described and remarks for the effective installation of steam distribution systems are given. (orig.) [Deutsch] Es ist nicht zu empfehlen, Befeuchterstrecken bzw. Dampfdiffusionsstrecken ausschliesslich ueber Nomogramme oder ueber eine entsprechende Software auszulegen. Zumindest sollte vorher genauestens geprueft werden, welche Parameter in die Berechnung mit einfliessen. Zur exakten Berechnung der Absorptionsstrecken in Zuluftsystemen muessen auch anlagenspezifische Faktoren beruecksichtigt werden. Die Erfahrung hat jedoch gezeigt, dass dem Begriff `Befeuchterstrecke` zu wenig Aufmerksamkeit gewidmet wird. Hierdurch koennen Fehler entstehen, die nur mit relativ hohem finanziellem Aufwand wieder zu korrigieren sind. Grundsaetzlich ...
We develop a general framework for the formulation of the action principle and the noether theorem for classical noncommutative field theories. We give a concrete example of an algebra that fits into this framework. It describes a scalar field theory on noncommutative minkowski space. We develop a notion of locality for this algebra and investigate the locality properties of localised interaction terms. This leads us to the definition of local functionals on the field algebra. We propose a scheme for the quantisation of these functionals. (orig.) [German] Wir entwickeln eine allgemeinen rahmen, der es erlaubt, das wirkungsprinzip und das noether-theorem fuer klassische nichtkommutative feldtheorien zu formulieren. Als ein konkretes beispiel betrachten wir eine algebra, die sich in diesem rahmen einfuegt, und die eine skalare feldtheorie auf dem nichtkommutativen minkowski-raum beschreibt. Fuer diese algebra wird ein lokalitaetsbegriff entwickelt und untersucht, welche ...
This research project aimed to determine the factors for the transfer of the elements silver (Ag), cerium (Ce), cobalt (Co), chrome (Cr), gallium (Ga), lanthanum (La), molybdenum (Mo), niobium (Nb), radium (Ra), ruthenium (Ru), antimony (sb), thorium (Th), titanium (Ti) and uranium (U) from food into the mother's milk. This factors will be used as a basic to check and derive activity values for the contamination of food and for radiation protection at working places of suckling women. For this purpose 19 mothers collected samples daily (2-8 weeks), using the duplicate method, of all the food they consumed as well as of their milk. After microwave-assisted digestion the element contents were analysed by mass-spectroscopy with inductive coupled plasma (ICP-MS). The results of the mothers who participate for more than 5 weeks were used to make a time lapse between the intake and transfer of the elements in the mothers milk visible. (orig.) [German] Ziel dieses Forschungsvorhabens ...
Minimally invasive thermotherapies for focal tissue destruction on the basis of laser-, microwave-, focused ultrasound-, or cryogeninduced changes of tissue temperature represent an alternative to surgical tissue ablation, particularly in the treatment of tumors. The thermotherapy modalities listed necessitate indirect guidance and monitoring, since they often do not lend themselves to immediate visual control. In the brain, in head and neck tumors, in the liver, and in the prostate, MRI reliably and accurately delineates both the positions of interstitial thermotherapy applicators and - in contrast-enhanced, T1-weighted images - the perfusion defects in tissue necrosis induced by thermotherapy. The transfer of results of in-vitro and in-vivo model studies to assess interstitial temperature and lesion development during thermotherapy to the actual treatment of patients, however, is still in an initial phase. Further development of both rapid MRI sequences and MRI scanners suited for ...
The establishment of the domestic market in Europe requires rules for the assignment of orders, with which a standardization of the rules of competition can be achieved and with which a discrimination of individual bidders can be prevented. Clients and contractors of power station equipments equally are affected by the definitions for the assignment of orders. The contribution under consideration is a regulation for the procurement of steam turbine systems. It is a supplement of the European standard DIN EN 45510:1998. The regulation integrates the former terms of delivery of association of the electricity industry (VDEW) for steam turbines as well as the collection and evaluation of a multiplicity of experiences of the VGB regulations.
By tests about pipe failure under extreme bending, moment at cross sections affected by circumferential cracks, admissible strains for securing the integrity in the area of a flow link are indicated. These are 7% for austenic and ferritic materials in the undisturbed cross section. From d/t-ratios of 20 onwards the strains are limited by pipe bulging on the pressure-load side. In this connection, circumferential flaws do not have any influence on the behaviour on the strained side, when their expansion does not exceed the investigated limitis of <60 circumferential expansion and crack depth of 0,3 t. (orig.)
So far, publications in turbomachinery engineering have tended to neglect the description of control systems and strategies which could be converted into practical guidelines for turbine operation. The contribution describes the power station turbine as a basis for modelling the control stage. The solutions will serve as a basis for further type-specific investigations of the problem. [German] Eine vornehmlich regelungstechnisch ausgerichtete Beschreibung des thermodynamisch-mechanischen Wirkungsgeschehens im Bereich der Regelstufe von Dampfturbinen sowie deren Umsetzung in schluessige, betriebsrelevante Aussagen fehlen bislang in der Turbomaschinenliteratur. Im Beitrag werden am Beispiel der Kraftwerksturbine die Grundlagen fuer eine modelltechnische Nachbildung der Regelstufe entwickelt. Die Loesungen dienen als Ausgangsbasis fuer weitere typenspezifische Bearbeitungen dieses Problems. (orig.)
Liberalization and the associated necessity of providing, where possible, inexpensive electrical energy, has intensified still further the demand for higher efficiency steam turbines. Accordingly, continuous efforts are being taken to improve all the flow guiding components of a steam turbine. Special attention is given here to the blading. (orig.) [Deutsch] Die Liberalisierung und die damit verbundene Notwendigkeit, elektrische Energie moeglichst preisguenstig zur Verfuegung zu stellen, hat die Forderung nach hohen Wirkungsgraden von Dampfturbinen weiter verschaerft. Es werden daher kontinuierlich Anstrengungen unternommen, alle stroemungsfuehrenden Teile einer Dampfturbine zu verbessern. Das Hauptaugenmerk gilt dabei der Beschaufelung. (orig.)
After cooling ceilings and source ventilation, simple air conditioning systems like thermal activation of concrete cores are gaining general acceptance. Parallel to this, ground source cooling systems are reducing the need for cold generation. Air conditioning systems of this type are favoured by producers of floor heating systems looking for a new market segment. [German] Nach Kuehldecken und Quellueftung gewinnen jetzt einfach aufgebaute Raumklimaanlagen, wie die thermische Betonkernaktivierung, immer mehr Anhaenger. Parallel dazu werden Verfahren zur Erdkaeltenutzung entwickelt, die den Anteil kuenstlich erzeugter Kaelte weiter zurueckdraengen. Forciert wird diese Art der Klimatisierung insbesondere durch die Hersteller von Fussbodenheizungen, fuer die sich hier ein neues Marktsegment eroeffnet. (orig.)
MPA research activities focus on fracture prevention and on the development of a generally applicable method of component integrity testing which, independent of the safety relevance of the components involved, is also part of ageing management. (orig.) [German] Die Forschungsaktivitaeten an der MPA im Hinblick auf die Erhoehung der Sicherheit und Zuverlaessigkeit komplex beanspruchter Bauteile orientieren sich an den Grundgedanken des Basissicherheitskonzepts (Prinzip des Bruchausschlusses). Zielsetzung war dabei die Entwicklung eines allgemein anwendbaren Nachweisverfahrens zur Komponentenintegritaet, das, abhaengig von der sicherheitstechnischen Relevanz der zu betrachtenden Komponenten, auch Bestandteil des Alterungsmanagements ist. (orig.)
The program introduced here for determining and describing the multi-axial creep of pipes is based, on the one hand, on the results of the nuclear process heat prototype plant material program and, on the other hand, on the possible load conditions which arise for evaluating accidents or extreme working situations. The basis of a theoretical description of multi-axial creep is the invariant theory in which both the von Mises configuration change hypothesis and the Norton creep law are included. Combined tension and torsion are also considered in detail, the superimposition of cyclic stresses in the tensile threshold area is discussed and cases of partial relaxation are explained. Experimental results for the discussed loads are introduced, which have led to satisfactory agreement between theory and experiment. (orig./MM).
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...
By using defined compositions based on industrial wastes of the hard-coal mining and a further waste material (red mud), which is obtained during the extraction process of alumina (BAYER-Process), it is possible to produce expanded-clay granulate requiring suitable preparation, shaping and firing at temperatures of about 1150 C. Some of the investigated parameters and aspects of this manufacturing process will be presented in this paper. (orig.) [German] Aus definierten Mischungen industrieller Reststoffe des Steinkohlenbergbaus (Bergematerial) mit einem weiteren Abfallstoff (Rotschlamm), der bei der Aluminiumoxidgewinnung nach dem BAYER-Verfahren anfaellt, laesst sich nach geeigneter Aufbereitung und Formgebung durch Brennen bei ca. 1150 C Blaehton-Grunulat herstellen. Auf einen Teil der untersuchten Parameter und ermittelten Zusammenhaenge soll im folgenden naeher eingegangen werden. (orig.)
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 ...
Plasma Immersion Ion Implantation (PIII) is a new hybrid technology for surface treatment of materials based on the principles of plasma nitriding and ion implantation. The equipment and the operation of the system are introduced. As well as providing an alternate method of ion implantation, it is possible to combine energetic ion bombardment with plasma nitriding. Different metal materials and treatment conditions have been studied. The capability of PIII-treatment to improve the properties of a wide range of metals has been proven. Application for forming tools and their industrial test has been successful. (orig.) [Deutsch] Die Plasmaimmersionsimplantation (PIII) ist eine neue Hybridtechnologie zur Behandlung von Werkstoffoberflaechen und basiert auf den Prinzipien des Plasmanitrierens und der Ionenimplantation. Die Anlagentechnik und die Arbeitsweise werden vorgestellt. Verfahrensspezifische Vorteile entstehen durch die Moeglichkeit, sowohl ...
Verification of guarantees mostly calls for measurements on the spot. The paper deals with the guarantees that apply to small hydroelectric power stations. Already when planning a plant it should be decided what guarantees are to be demanded and how they can be verified. Specifically, measurements to verify guaranteed performance and efficiency on the spot are dealt with. Details are not given. Rather, the report wants to give an overview of methods and aspects to be taken heed of. For in-depth information, the reader is referred to the corresponding standards and guidelines. (orig.) [Deutsch] Zur Ueberpruefung von Garantien ist meistens die Durchfuehrung von Messungen vorort notwendig. Es werden die Garantien behandelt, die bei Kleinwasserkraftanlagen in Frage kommen. Bereits bei der Planung der Anlage sollte entschieden werden, welche Garantien gefordert werden sollen und wie sie ueberprueft werden koennen. Es wird ...
One part of the RWE measure catalogue in order to guarantee an environmental friendly and competitive electric power generation based on brown coal is to carry out measures improving the efficiency at existing steam turbines in RWE brown coal power plants. Since 1993 a total of 21 steam turbines with a gross capacity of 7,100 MW or net capacity of 6540 MW - this corresponds to approximately 70 % of the installed RWE brown coal power plant capacity - have been improved with an investment of approximately DM 500 million. The net block efficiency has been increased by 1.3 % on average. The planned net capacity increase of approximately 250 MW is still going to be achieved taking into account the pending enhancements. Nuclear power plant turbines have been successfully improved in the same way. Apart from the described retrofit programme measures to improve efficiency are carried out at further steam turbines of brown coal power plants. In the frame of this talk the measures taken are ...
As one of the largest contractors for the construction of ethylene plants featuring steam cracker furnaces as their core component Linde AG has examined the `real` chemical recycling of polymers in steam cracker furnaces as an alternative to their thermal utilisation. In steam cracker furnaces the feedstock, i.e., hydrocarbons, is broken down to ethylene, propylene, and other valuable products in a steam dilution of approx. 800-870 C. In the ideal case, if polyolefins are used as feedstock, then the initial product which led to the polymers can be fully recycled. In this context a series of experiments was carried out in a laboratory-scale cracker plant. The purpose of this was to demonstrate the technical feasibility and the economic advantage of using recycling polyethylene or polypropylene as feedstock for steam cracker plants. (orig./SR) [Deutsch] Die Linde AG als einer der bedeutendsten Kontraktoren fuer den Bau von Ethylenanlagen, deren Herzstueck die ...
The article deals with the problem of a humidity addition to thermal conductivity, diffusion and latent heat effects in heat transfer through building components. It shows with examples humidity effects for exterior walls with core insulation, with composite insulation system as well as for insulated roof membrane assemblies. From these it can be summarized that - sorption humidity is for today`s construction conditions (good thermal insulation and humidity protection) a suitable reference quantity for the determination of practice-oriented, substance-specific and physically correct humidity additions to the thermal conductivity of hygroscopic components; - diffusion and latent heat effects are in case of good rain imperviousness and low water absorbing capacity of the exterior component layers of secondary importance for transmission heat losses; - an increase in insulating layer thickness in order to improve the thermal insulation is possible without humidity problems; - today`s ...
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 ...
Only about 25% of residue accumulating in the Federal Republic of Germany is currently used for the purposes of energy. This residue will be converted into fuel for power stations by the Omega process when the dumping of waste with a calorific value in excess of 5 MJ/kg is prohibited with effect from 2005. This oxygen melting process is suitable for the local use of substitute fuels. Waste is converted into a high-quality synthesis gas with a wide range of uses. The Omega process combines drying, thermal decomposition, gasification and melting of the material used in a single-stage process. This is now technologically possible for the first time by combining a metallurgical cupola furnace with a traditional gas producer. The highly-calorific synthesis gas produced by the Omega process can be used in block heat and power stations or as an industrial fuel gas, instead of natural gas. It is also suitable as a starting material for synthesising methanol. The gas is specifically processed ...
With publication the fire design rules of the Eurocode and the national application documents (NAD) for the first time also calculation methods of constructive structural fire protection are available. This dimensioning of components and structures in fire case is based on the normal temperature design on Eurocodes and can be applied in the future as alternative to the classical fire design method of the German standard DIN 4102 part 4. In this contribution a view of the proof procedures of the Eurocode fire protection parts and the arrangements of the NADs is given as soon as the application of these fire design rules in Germany is described. (orig.) [German] Mit der Veroeffentlichung der Eurocode-Brandschutzteile als Vornormen und der zugehoerigen nationalen Anwendungsregelungen (NAD) als DIN-Fachberichte stehen erstmals auch rechnerische Nachweisverfahren fuer den konstruktiven baulichen Brandschutz zur Verfuegung. Diese brandschutztechnische Bemessung ...
High temperature components of power plants are in many cases subjected to variable loading conditions such as cyclic creep or strain cycling. Therefore the cyclic behaviour of important heat resistant steels has been investigated under stress control and to a smaller extent under strain control. The behaviour under cyclic creep rupture conditions was determined in long term experiments covering a wide range of loading conditions. This behaviour can be described with the modified life fraction rule and a factor concept of relative life for single stage cycles and additionally with a multistep hypothesis for multi-stage cycles. The description can be adapted to estimate the life consumption under service type random conditions. The strain cycling behaviour was investigated in regard to the conditions of the heated surface of large components. To simulate this type of loading and to generate long term creep fatigue data, a service type strain cycle was developed. Anisothermal and ...
The R and D activities of the institute focused on two major projects, ``Molecular and cellular environmental toxicology``, and ``Biophysics of multi-cellular systems``. For assessment of health risks emanating from the uptake of heavy metal compounds, work performed under the first mentioned project studies the formation of allergy-inducing metabolic products from membrane lipids, and the effects of related cellular signaling processes. These studies are accompanied by an approach to quantify and classify the toxicity of environmental organometallic compounds. Another major task is research into the pathogenesis of lung disease induced by dusts, gases, and gas-dust mixtures and the liberation of inflammatory agents by immunological cell reactions (alveolar macrophages). Atomic force microscopy is the tool used to visualize the related dynamic changes in bronchial cells. Studies for detection of the localisation and structure of the Fe-Mo co-factor in nitrogenase by means of the method ...
The presented paper describes the formulation of the fractional mass balances which are used to calculate the concentration and size distribution of char in the balance cells of a circulating fluidized bed boiler. In case of using the shrinking core model additionally the distribution of conversion of the char particles is calculated. Basically two reaction models (a shrinking particle and a shrinking core model) are available to describe the combustion process. The model considers all essential physico/chemical phenomena (primary fragmentation, attrition, mass transfer to gas phase) which have to be taken into account for the description of the combustion process. The model is part of an overall simulation program for circulating fluidized bed boilers. This engineering simulator has been developed to return the main performance parameters of such systems like temperature along the furnace height, size distribution of balanced solid components, heat flows at the different heat ...
Early in 1988 RWE decided to overhaul the power station at Goldenberg. This was necessary due to the age of the plant, the obligation to supply heat and process steam and recent amendments of environmental legislation. After analysing demands and needs one developed a plant concept with a 290 t/h and a 400 t/h steam generator. Due to lack of space the decision was made in favour of a circulating atmospheric fluidised bed combustion instead of steam generators with pulverised lignite combustion as these steam generators take up much more space due to the legally required desulphurisation plants for gaseous emissions. Apart from generating steam RWE wishes to gain experience with this combustion technology and test it for suitability and use in large-scale plant. (orig./KO) [Deutsch] Aufgrund des fortgeschrittenen Alters, der aktuellen Umweltschutzgesetzgebung sowie bestehender Versorgungsverpflichtungen fuer Waerme und Prozessdampf wurde Anfang 1988 von der RWE ...
In the year 1996 the spheres of competence of several DLR-Institutes working in the areas of fluid dynamics, reaction kinetics, combustion, numerical methods and laser measuring techniques have been brought together while contributing to the internal DLR project 'combustion chamber modelling (BKM)', in order to proceed with the computational simulation of combustion processes in combustion chambers of gas turbines. The main issue was the development of a research code for numerical simulation of fluid flow in real combustion chambers. Here the development of computational models of physical and chemical processes was emphasized, among other processes the formation of soot was treated. Moreover, a worldwide outstanding database of measured data for the purpose of code validation has been created within the framework of the BKM project using the laboratory facilities of the DLR, which are in Germany unique for the experimental investigation of the various processes in ...
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 ...
{gamma} Ti-Al have a higher temperature potential than commercial titanium alloys and a 50 percent lower density than nickel base superalloys. Application temperatures in aircraft turbines are 750 C and above. The authors investigated the high-temperature performance of {gamma} TiAl, i.e. isothermal high-temperature fatigue and the type and importance of damage. LCF experiments were made in the temperature range of brittle/ductile transition in air and vacuum. Damage mechanisms were characterized by microstructural investigations. [German] Unter den modernen Hochtemperaturwerkstoffen kommt den Legierungen auf Basis von {gamma}-TiAl eine zunehmend wichtige Bedeutung zu, da diese Werkstoffe ein hoeheres Temperaturpotential als alle kommerziellen Titanlegierungen haben und eine im Vergleich zu den Nickelbasis-Superlegierungen um ca. 50% geringere Dichte aufweisen. TiAl-Werkstoffe, die z.B. fuer Schaufeln und Gehaeuse in Flugzeugturbinen eingesetzt werden sollen, ...
This report describes work carried out in the context of TurboTech Interim for the development of a system for monitoring stationary gas turbines for approaching the stability limit of the compressor. The requirements for the system components were defined and the suitability of different types and positions of pressure sensors were examined and evaluated. It was found very early in the work that, due to the complexity of the object being monitored, one would not succeed in finding a simple criterion for monitoring the pump limit. Rather, apart from the selection of suitable sensors and optimum positions, one must analyse the present signals in different ways and create a decision matrix from this. Existing work on this subject is mostly concerned with the phenomena in the context of experiments on experimental compressors or is not suitable for the requirements of stationary industrial gas turbines. The project is being carried out in the context of TurboTech II with the main aims of: ...
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 ...
During their life, intervertebral discs undergo degenerative changes which need not necessarily become lesions. Conventional X-rays do not provide information on the condition of the intervertebral discs, so MRT or CT are recommended as primary techniques as they are non-invasive. Invasive methods like myelography and especially discography should not be used unless a case is highly problematic. In infants with pains in the back, MRT should be carried out as early as possible as there is nearly always an organic cause. (orig.) [German] Die Bandscheibe ist im Laufe des Lebens degenerativen Veraenderungen unterworfen, die klinisch zu Beschwerden fuehren koennen, aber nicht fuehren muessen. Konventionlle Roentgenaufnahmen lassen zwar die Hoehenminderung des Bandscheibenfachs und begleitende knoecherne Veraenderungen erkennen, nicht aber den Zustand der Bandscheibe selbst. Die Beurteilung der Bandscheibe und des Knochens gelingt mit der CT, die parallel zum Bandscheibenfach durchgefuehrt ...
To determined precisely a possible connection between the amount of copper in tap-water and the risk of early childhood liver disease, it was attempted through an epidemiological survey, to determine the extent of excessive concentrations of copper in the tap-water of households with copper pipes. Water samples from 956 households were tested for copper, and the state of health of the infants in these households was documented. Infants who had been fed using water with a copper concentration of 0.8 mg/l or more received a paediatric examination with a blood serum analysis to rule out any liver damage. A copper level greater than 0.8 mg/l was found in only 2% of the households examined. Eight infants were examined by a paediatrician and their serum was analysed. These infants had either been breast-fed to the 12th week or had received more than 200 ml of tap water per day during first 12 months. None of the infants examined showed any signs of liver malfunction. From the results of the ...
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 ...
FLUTAN is a highly vectorized computer code for 3-D fluiddynamic and thermal-hydraulic analyses in cartesian and cylinder coordinates. It is related to the family of COMMIX codes originally developed at Argonne National Laboratory, USA. To a large extent, FLUTAN relies on basic concepts and structures imported from COMMIX-1B and COMMIX-2 which were made available to KfK in the frame of cooperation contracts in the fast reactor safety field. While on the one hand not all features of the original COMMIX versions have been implemented in FLUTAN, the code on the other hand includes some essential innovative options like CRESOR solution algorithm, general 3-dimensional rebalacing scheme for solving the pressure equation, and LECUSSO-QUICK-FRAM techniques suitable for reducing `numerical diffusion` in both the enthalphy and momentum equations. This report provides users with detailed input instructions, presents formulations of the various model options, and explains by means of ...
Nickel-based alloys are presently used as brazing filler metals for components which undergo mechanical stress in corrosive conditions, f. e. heat exchangers. When soldering chrome containing steel parts with nickel based brazing filler metals additionally containing boron and silicon a reaction of chrome and boron can occur. This evolution of chromium borides, depositing on grain boundaries, causes a lack of chrome in the steel part. A drop of the chrome content in the parts below 13 % leads to a loss of corrosion resistance. It is possible to change the microstructure of brazing joints by modification with chromium and molybdenum. Continuous brittle phases could be successfully avoided with this modification. Furthermore it could be shown that the choice of additives, the heating respectively cooling rate and the brazing temperature have important influence on the microstructure evolution and therefore on the mechanical and corrosive properties of joints. (Abstract Copyright [2008], ...
The development of new steels is always a challenge for the manufacturer of filler metals. In many cases it is obvious that some properties of the base metal cannot be fulfilled with matching filler metals. In some cases, dissimilar filler metals can solve the problem in some cases, there is no chance to meet the requirements of the base metal (for example yield strengths of new ultra high strength steels). This paper deals with different kinds of new steels and the requirements for the weld metal with examples from motor car industry (Mangan Austenite), crane (Ultra high strength steels), earthmoving machinery (Wear-resistant steels) and offshore (Supermartensitic steels). Specific problems will be discussed and best solutions will be highlighted. These examples make clear that the success of new kinds of steels in the market depends on solving the joining problems of these steels. (Abstract Copyright [2007], Wiley Periodicals, Inc.) [German] Die Entwicklung von ...
The nozzle-group regulation of steam turbines plays furtheron an important role in the operation of power stations owing to modern, adaptable control-technical valve timing possibilities. New procedures for a choice-connection of different nozzle areas via the control valves as well as the use of valve laps require, however, a differentiated consideration of the loss mechanism in the inlet area of the turbine, in order to be able to assess and minimize its specific heat consumption also at the operational points outside the layout- and calculation-technically fixed guarantee or valve points, respectively. The basic technical-physical stages to this are explained. (orig.) [Deutsch] Die Duesengruppenregelung von Dampfturbinen nimmt nicht zuletzt dank moderner, anpassungsfaehiger leittechnischer Ventilansteuerungsmoeglichkeiten weiterhin eine bedeutende Stellung beim Betrieb von Kraftwerken ein. Neue Verfahren zur wahlweisen ...
In an extended case report, we discuss four cases with masses in the lacrimal fossa representing the most important entities in this region (lymphoma, pleomorphadenoma, inflammatory pseudotumor, and malignant epithelial tumor). The different indications for CT and MRI are explained. For the differential diagnosis of lacrimal gland lesions, the following imaging parameters are important: The shape of the lacrimal gland, the inner structure, the degree of contrast enhancement, and the surrounding bony structures. In the evaluation of the expansion of lacrimal gland lesions, CT in thin slices with multiplanar reconstructions is equal to MRI. However, the contrast-enhancement of lacrimal glands is better evaluated with MRI than with CT. The bony structures are better visualized on CT than on MRI. (orig.) [Deutsch] In einem erweiterten Fallbericht wird ueber die vier grossen Entitaeten bei Traenendruesenraumforderungen berichtet (Lymphom, pleomorphes Adenom, entzuendlicher Pseudotumor und ...
56 patients with the clinical diagnosis of sprained ankles were investigated. Evaluation of the anterior (AFTL) and posterior fibulotalar ligament (PFTL) was performed with the foot in dorsiflexion (20 ) and of the fibulo calcanear ligament (FCL) in plantarflexion (45 ). Axial T{sub 1}w-SE and T{sub 2}w-TSE images were obtained. Full-length visualisation of ligmaments in one slice and the extent of injury were evaluated. 12 ankle injuries were confirmed by operation. With MRI full-length visualisation of lateral ankle ligaments was possible in 86%. A partial/complete rupture of the AFTL was noticed in 33/64% and of the FCI in 29/39%, and of the PFTL in 27/5%. Sensitivity/specificity of MRI when compared to surgery was 100/100% for injuries of the AFTL, 64/100% for the FCL, and 33/78% for the PFTL. (orig./MG) [Deutsch] 56 Patienten wurden mit der klinischen Diagnose einer frischen Supinationsverletzung des oberen Sprunggelenkes untersucht. Das Lig. talofibulare anterius (TFA) und ...
The low budgets of local governments and Federal States in Germany as well as lack of financial means of renters delaying thorough modernisation of existing heating systems in residential and public buildings, novel heat supply and related customer services are emerging on the market. Heat supply companies and housing construction associations increasingly use modern electronics and telecommunication systems for heating system upgrading and reliable operation and maintenance. This option holds an enormous potential of saving money today and in the future. Installation of remote control and maintenance systems and the related telephone-based services offer fast repair and other services via electronic telecommunications systems, thus saving money and manpower for the repair services of heat suppliers or plumbers, or financial losses due to rents being docked for broken down heating systems. Such remote control and maintenance systems however need to be reasonable in price, and versatile ...
High-strength, fully hardening steels are used in general for applications involving severe wear and frequently also additional cyclic stress. For the latter condition, the available information and experimental data for component dimensioning are insufficient. Work reported in the dissertation therefore was intended to establish experimental information showing the performance of the bainitic roller bearing steel 100Cr6 and deducing rules of applicability to components, of the fatigue strength data obtained with the specimens. Various models for calculating the fatigue strength are presented together with their application to the steel 100Cr6. The results show that the weakest link model is a good concept for fatigue strength calculation, taking into account multiaxial loading. (orig/CB) [Deutsch] Hochfeste durchhaertende Staehle unterliegen in der Regel hohen Verschleissbeanspruchungen und werden darueber hinaus oftmals zusaetzlich schwingend beansprucht. Fuer die schwingende ...
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. ...
The issue of projecting policies ensuring appropriate energy supply in the future has become more important in Germany after conclusion of the agreement on a long-term nuclear power phase-out. A recent comparative analysis of a selection of scientific studies forecasting the implications of a nuclear power phase-out has shown that there is demand for more studies examining the issue in greater detail, and on the basis of an enlarged scope of research topics. Hence the present study, intended as a preliminary analysis, will investigate the potential, conditions of successful application, conceivable support schemes, and effects of those policy options that in any case, apart from the nuclear power phase-out scenario, are of essential importance in the context of building the proper conditions for sustainable development of Germany's energy sector. The options and strategies examined are: stepping up energy efficiency programmes and incentives, enhancing exploitation of the ...
When the use of retarders in utility vehicles increased in the middle of the 80s, the Forschungsvereinigung Automobiltechnik (FAT) commissioned a study on the safety aspect of this braking technology in trucks. Retarders are wear-free permanent brakes that are fitted in the drive transmission system of utility vehicles, thereby generating braking forces only at the wheels of the live shaft. The question of the possible overbraking of the live shafts was just as well investigated as the interaction between the retarder and service brake in so-called integrated braking systems, and both under conditions of low adhesion as well as in the border area of the dynamics of vehicle movement. This subject met with considerable joint interest on the part of the motor vehicle industry as well as of manufacturers of towed vehicles and unit sets. FAT, therefore, commissioned the Institut fuer Kraftfahrwesen of the University of Hannover to carry out a three-phase research project on the braking ...
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 ...
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 ...
Against the background of more severe limitation of particle emission in all application areas of Diesel engines, it is necessary to monitor the particle emission, but also the chemical composition of the particles. The basis of assessing particle emission is formed by gravimetric determination of the particle concentration from exhaust gas diluted with particle-free ambient air, with a maximum temperature of 52 degrees C at the sampling position. While it is already possible, using the part flow dilution system, to take samples locally, previously the subsequent particle determination and characterisation could only be done in a chemical laboratory. For this reason, the C/S particle measurement process was developed as an alternative to gravimetry, which can be used locally, eg: on ships and which makes it possible to determine the particle mass and composition. This process is based on a thermographic carbon and sulphate determination. Comparative investigations were done both on ...
1. In order to carry out isothermic crystal growth experiments of YBCO the 123 primary crystallization field was determined by means of phase diagram investigations and crystal growth experiments at different oxygen partial pressure. 2. YBCO single crystals of high crystallographic perfection were grown and conclusions on the flux pinning mechanism were drawn. 3. By means of Liquid Phase Epitaxy (LPE) single crystalline (Tc{approx}90 K; {Delta}T{<=}0.5 K) c- and a,b- YBCO fils have been prepared on NdGaO{sub 3} and LaGaO{sub 3} substrates. The films were characterized structurally and magnetically. 4. Our fist melt textured YBCO ``single crystals`` possess intracrystalline critical current densities >10{sup 4} A/cm{sup 2} at B{<=}2T. The irreversibility inductions are {<=}6 T at 77 K. A simple demonstrator was constructed together with the IFW Dresden and a growth model was developed. 5. Using above all torque magnetometer measurements we separated intrinsic pinning effects ...
Magnetic fields can be compensated by opposing fields. This principle can be applied for reducing the magnetic fields emanating from high-voltage transmission lines or found in residential or commercial buildings. The article shows a number of concrete options for reducing magnetic fields in the vicinity of high-voltage lines through appropriate conductor configuration on the one hand, and a novel method using Helmholtz coils for compensating those fields in buildings. (orig.) [Deutsch] Magnetische Felder koennen durch Gegenfelder kompensiert werden. Dieses Prinzip laesst sich sowohl auf Hochspannungsleitungen als auch auf Wohn- und Arbeitsraeume uebertragen. Der Artikel zeigt konkrete Moeglichkeiten, wie einerseits Magnetfelder von Hochspannungsleitungen durch eine geeignete Konfiguration der Leiter reduziert werden koennen, und beschreibt andererseits eine neue Methode zur Reduktion solcher Felder in Wohn- und Arbeitsraeumen mittels ...
A model describes the effect of changes to the pore structure on the mechanical properties of semi-coke during coking. The gap tensile experiment makes it possible to determine the mechanical properties of the coke and semi-coke; a theoretical analysis is valid for the deformation of samples in the gap tensile test, by which the gap tensile strength of the coke can be determined, and by which a method for the simultaneous determination of the effective modulus of elasticity was developed. The effect of the pore structure on the mechanical properties is given in semi-empirical equations. The main point here is to check whether a pore in the coke can be regarded as a Griffith crack, and whether the interaction of pores can be neglected. A model which takes the pore distribution into account was also developed and tested. A model for the change of pore structure during coking, which includes the contraction of the semi-coke, and which presupposes a difference in direction of the ...
The generation of a defined swivel momentum in car door hinges depends on numerous constructional and technical manufacturing parameters. If these parameters and their influence are to be investigated, then in addition to detailed experiments with variations in the parameters, methods are also required which enable the measuring data produced to be assessed in such a way that, in general, the non-linear relationships between initial and target size can be described sufficiently accurately. This paper explains the parameter reduction necessary in the experimental investigation, gives the results of the data assessment with conventional statistical methods and describes in particular the use of artificial neural networks (ANN) to construct so-called 'neuro hinge models' on the basis of the data resulting from the experiments. Parameter variations can be simulated with the hinge models and in this way optimal constructional and technical manufacturing values for ...
Efficiency of energy coversion of primary energy to an end use in industrial countries is about 30%. This is insufficient. Evaluating on basis of exergy efficiency becomes only about 15%. Usage of fuel cells give a great chance to improve efficiency. This concerns in particular to high temperature fuel cell systems SOFC and MCFC as well as their combination with heat pumps. [German] Die Effizienz der Energieversorgung in Industrielaendern ist energetisch bewertet mit rund 30 % unbefriedigend. Legt man den strengeren, energiewirtschaftlich treffenderen exergetischen Massstab an, halbiert sich dieser Wert sogar. Brennstoffzellen bieten durch ihren Einsatz Moeglichkeiten zur Effizienzerhoehung. Dies gilt insbesondere fuer die Hochtemperatursysteme SOFC und MCFC sowie deren Verbund mit Waermepumpen.
Rehabilitation of the abandoned uranium mining areas in Saxonia and Thuringia is a task posing also legal problems. The radiation protection laws of the former GDR continued to be effective to a great extent and proved to be a legal basis not ``perfect`` in formal terms, but suitably efficient in practice to tackle the manifold problems encountered in the land reclamation and waste disposal work. Originally intended to serve as a legal interim regime awaiting amendment at a later date, the body of laws available for the task proved to be a sufficient basis. (orig./HP) [Deutsch] Das fortgeltende Strahlenschutzrecht der frueheren DDR hat sich zwar nicht als formal `perfektes`, in der Sache aber strahlenschutzgerechtes und praktikables Instrument zur Loesung der anstehenden Sanierungsaufgaben erwiesen. Bei seiner Beurteilung darf nicht ausser Acht gelassen werden, dass die Ueberleitung dieses Rechts seinerzeit aus der Not eines kurzfristigen Regelungsbedearfs geboren ...
The austenitic nitrided Cr-Mn steels CrMnN 1812, CrMnNMo 1714 and CrNiTi 1810 has been investigated in chloride nitric acid at temperature 20-60 C. The Potentials of pitting nucleation and the time for pitting initiation has been determinate by the hronoamperometric method. It was established that alloying only with nitrogen is not sufficient procedure for obtaining of resistive to localised corrosion steel structure. Of importance for the resistance to localised corrosion of Cr-Mn steels is alloying with molybdenum. (orig.) [Deutsch] Die austenitischen stickstoffhaltigen Cr-Mn Staehle CrMnN 1812, CrMnNMo 1714 und der klassische CrNiTi 1810 wurden in chloridhaltigen Salpetersaeureloesungen im Temperaturbereich 20-60 C untersucht. Durch die hronoamperometrische Methode wurden die Potentiale der Lochfrassbildung und die Zeit zur Initiierung der Lochfrasskorrosion bestimmt. Man stellte fest, dass das Legieren der Staehle nur mit Stickstoff eine nicht genuegende ...
The failure rate of dashpots has been determined on the basis of the results of annually recurring function tests on hydraulic dashpots, in order to determine the effects of longer test cycles on the safety of systems GKN I and GKN II. The use of a calculation method made it possible to establish the number of defective dashpots in the system as a whole. A subsequent investigation illustrated the way in which this figure changes when the test interval is increased from four to ten years, and the effects of this on system safety. (orig.) [Deutsch] Zur Ermittlung der Auswirkungen verlaengerter Pruefzyklen auf die Sicherheit der Anlagen GKN I und GKN II wurde, basierend auf Ergebnisse der jaehrlichen Funktionspruefung an hydraulischen Stossbremsen, die Fehlerrate der Stossbremsen bestimmt. Mit Hilfe eines Berechnungsverfahrens konnte die Anzahl maengelbehafteter Stossbremsen in der Gesamtanlage bestimmt werden. Eine anschliessende Untersuchung zeigte, wie sich dieser ...
Beside sucker-rod-type pumps and submersible centrifugal pumps, excentric screw pumps (so-called progressing cavity pumps) belong to standard conveyors in the production of crude oil. The authors of the contribution under consideration present the further development of excentric screw pumps with respect to the reduction of fluid levels in gas wells. This further development is based on a co-operation between the operator (Rohoel Aufsuchungs AG (Gampern, Austria)), the pump supplier (NETZSCH Oilfield Products GmbH (Selb, Federal Republic of Germany)) and the Institute for Process Technologies and Machinery at the University of Erlangen-Nuernberg (Federal Republic of Germany). The authors report on first attempts with the excentric screw pump at Weizberg (Federal Republic of Germany), material investigations at the University of Erlangen-Nuernberg, optimization of pump components and pump systems as well as on the optimization of the entire drainage process. Although excentric screw ...
The criterion the study is based on in evaluating environmental risks is the possibility of harmful changes in air, water and soils rather than the harmful environmental impacts these changes are caused by. The two significant criteria, i.e. the evaluated environmental hazards potentials or 'value parameters', and the evaluated damage-to-the-environment probabilities or 'safety parameters', reveal the respective environmental risks or 'risk factors'. These risk factors are classified by 23 environmental risk parameters for differentiation between low-risk and high-aid for pollution abatement measures provided that one fixes acceptance limits for the environmental parameters. As a rule the environmental risks of technical facilities which handle hazardous materials can be evaluated appropriately and the results can be compared. (orig./HSCH).
Problems with the refractory liners of incinerator combustion chambers have accompanied incinerators from the very beginning. They increased during the past decade, owing to higher combustion temperatures required by law (17. BImSchV), the higher calorific values of the waste to be combusted, and the higher or changed pollutant concentrations in the waste materials. This caused the providers and the materials and the producers of incinerators to develop new refractory products and new design concepts, with a great variety of processes and cost levels. [German] Seit Beginn der Abfallverbrennung, insbesondere aber mit zunehmender Tendenz in den vergangenen 10 Jahren, wird ueber Probleme mit der Feuerfestauskleidung in den Brennkammern von Abfallverbrennungsanlagen geklagt. Als Gruende fuer die zunehmenden Korrosionsprobleme werden die hoeheren gesetzlich geforderten Verbrennungstemperaturen (17. BImSchV), die hoeheren Heizwerte der verbrannten Abfaelle und die ...
Report by a participant in the International Nuclear Law School. In 2001, this advanced training course was first offered by the OECD-NEA together with the University of Montpellier and other international partners. This effort is intended to provide an overview of nuclear law, a discipline normally playing a subordinate role in curricula. In this way, a contribution is to be made to the important preservation of the existing knowledge base and to increasing know-how in this field. In 2003, the International Nuclear Law School will be continued with a new curriculum addressed to all interested participants. (orig.) [German] Erfahrungsbericht eines Teilnehmers der Internationalen Schule fuer Nuklearrecht 2002 an der Universitaet Montpellier. Erstmals im Jahr 2001 wurde diese Fortbildungsveranstaltung von der Nuclear Energy Agency der Organisation for Economic Co-operation and Development (OECD-NEA) zusammen mit der Universitaet Montpellier und weiteren ...
The European Court of Justice has defined a clear means by which waste utilisation methods can be distinguished from waste disposal methods in a logical, well-understandable manner. With its stringent definition of ''utilisation'' this judgement points the way to quality-oriented waste management practices. We do not share the often voiced fear that this decision will lead to an increased incineration of compound wastes in industrial plants such as cement works. From the fact that, according to the decision by the European Court of Justice, wastes destined for utilisation fulfil a certain purpose and therefore, if not available in sufficient quantity must be replaced by primary raw materials, it follows that these wastes are required to fulfil specific quality criteria. This is rarely the case, if at all, with compound wastes. From the viewpoint of Luxembourg the decision by the European Court of Justice can be regarded as a positive impulse towards ...
DMT has developed what is called the stepped reforming process. This is an allothermal gasification process which uses hydrogen for a gasification medium. First the biomass is pyrolised by means of a heat transfer material. The escaping gaseous and condensable constituents are hydrogenated, heated in a reforming stage and are made to react to a hydrogen-rich product gas by means of homogeneous gasification. The heat required for this is provided by burning the pyrolysis coke. This makes it possible to dispense with process stages that would involve gasification of solid material and hence require higher pressure levels. The present process also works at ambient pressure. Moreover, stepped reforming promises a number of additional advantages: low-tar product gas containing 60% hydrogen, high cold gas efficiency, no wastewater arisings, robust operating behaviour. This paper outlines the basic ideas that led to the development of stepped reforming process and describes its diverse ...
Clinical studies have proved the effectiveness of local ablading methods in pations with non-resectable liver metastases of a colorectal carcinoma. RF ablation and LITT are a potentially curative therapy option and an alternative to systemic chemotherapy; the latter is carried out primarily for reducing tumour size with the goal of secondary resectability. The number of R0-sesectable metastases can be enhanced by a combined therapy of surgery and local ablading methods, e.g. by preoperative, intraoperative or postoperative ablasion of further non-resectable tumours during surgery. Systemic chemotherapy combined with surgery as an adjuvant method is not recommended unless in cases of non-abladable tumour recidivation. Currently, systemic chemotherapy is used as a neo-adjuvant therapy for tumour size reduction with the goal of secondary resectability or, in case of inoperability, local ablation. (orig.) [German] Abladierende Verfahren. Klinische Studien belegen die Effektivitaet der ...
The basis of assessment for particulate exhaust emissions is the gravimetric analysis of the particle concentration of diluted exhaust gases at temperatures below 52 C. This is very time consuming and takes sufficient sensitivity at low particulate emission rates like downstream of particle filters. For this reason the C/S-method, based on the thermographic analysis of carbon and sulfur, has been developed as an alternative to the gravimetric anallysis. This method yields particle mass as well as the main particle compounds. Comparisons between both methods have been carried out for heavy duty and automobile diesel engines as well as road vehicles and large diesel engines. The tests were conducted with commercial diesel fuel and also with other fuels, such as heavy oils. It could be shown that the C/S-procedure yields the same results as the gravimetric procedure independent of engine, engine mode and kind of fuel. The analysis of all important particulate compounds - elemental carbon ...
This update of a system concept entitled ``Maritime hazard prevention and water protection`` makes full use of the technical room for maneuver while considering that reasonable financial and economic conditions must be provided. The update allows on to continue or start the exploitation of feasible technical, logistic and information-technology development potentials. The same applies to the national maritime traffic safety measures developed for the German waterways. Considering the maritime hazards that have been prevailing in the coastal areas of the German North Sea, the conducted damage risk investigations suggest that a large-scale, disastrous oil contamination of the mud flats ecosystem cannot be excluded or controlled definitely in spite of the numerous measures taken. (orig.) [Deutsch] Mit der vorgelegten Fortschreibung zum Systemkonzept ``Gefahrenabwehr und Gewaesserschutz im Seeverkehr`` werden die technisch realisierten Handlungsspielraeume unter Beachtung der finanziellen ...
This 7th edition reveals the progress in steam engineering and the great future potential of steam engineering applications. Pollution abatement and design experiences gained during the operation of existing plants, and experiences gained in waste incineration are of environmental relevance. Recent materials developments and knowledge, e.g. as regards pipes and fittings, have been making significant contributions to supercritical-steam efficiency improvements. Emphasis is also placed on automation, control engineering, water chemistry etc., and on regulations, licensing procedures, and the training of the staff of plants. (orig./KOW) [Deutsch] Die nunmehr vorliegende 7. Ausgabe zeigt den Fortschritt und das zukuenftig noch erhebliche Potential dieser Technik auf. Erfahrungen mit den nun schon seit Jahren laufenden Anlagen zur Schadstoffminderung, Konstruktion und Auslegung sowie Betriebserfahrungen zur thermischen Abfallverwertung sind ...
Heat pumps for residential space heating become an increasingly important alternative to the conventional heating system like gas or oil burner. They offer the opportunity to reduce CO{sub 2} emission associated with heating residential homes in Germany. High compressors efficiency and a wide operating map are required so that an economically viable heat pumps is achieved which meets the operational conditions for present and future heating systems. The design parameter of existing heating systems require relatively high condensing temperatures which can be achieved with dedicated compressor designs. The design of Scroll compressors specially adapted to these heat pumps is shown and their operation is explained. (orig.) [German] Waermepumpen fuer die Wohnraumheizung gewinnen an Bedeutung als Alternative zur konventionellen Gas- oder Oelheizung. Sie bieten die Moeglichkeit, die mit der Gebaeudeheizung verbundene Emission von Kohlendioxid in ...
With the development of the latent heat store and its inclusion in the conventional heating control of cars, success has been achieved both in increasing comfort and in making an important contribution to safety of driving. Great store is set in development of the system on its environmental friendliness, for example by the thorough use of environmentally friendly and reusable materials. This also means the use of clean materials. It was shown that the latent heat store (apart from the aspects of comfort and safety of driving) can also make a contribution to saving fuel and reducing the exhaust gas. The sum total of the advantages makes it clear that the latent heat store introduced here is a very environmentally friendly system with multi-functional properties. (orig.) [Deutsch] Mit der Entwicklung des Latentwaermespeichers und seiner Einbindung in die konventionelle Heizungsregelung von Automobilen ist es gelungen, sowohl den Komfort deutlich zu erhoehen als auch ...
The book is a German translation of an American textbook with the original title ''MRI Survival Guide'' and is intended to serve as an introductory guide for beginners or a reference book for quick information. Readers will find information on the fundamentals of the technology and methodology of MRI as well as all details of relevance to practice in a precise and easy-to-grasp arrangement, covering all anatomic areas of interest, illustrations and descriptions of characteristic signs of pathologic processes, high-quality and unusually large-sized diagnostic pictures, a modern didactic concept for quick orientiation, including surveys, tables, and reproductions for visualisation of contents. (orig./CB) [German] Praktisch jeder Mediziner wird im Laufe seiner Berufstaetigkeit mit der MRT konfrontiert - unabhaengig davon ob in der Radiologie, Orthopaedie, Gynaekologie, Chirurgie, Neurologie oder sonstigen Fachrichtung. Das Buch ist eine Uebersetzung ...
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 steigenden ...
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 ...
Purpose: To visualise the vessel wall of the descending thoracic aorta using magnetic resonance imaging. To evaluate the diagnostic potential of tailored T{sub 1}-weighted sequences with contrast enhancement to assess systemic atherosclerotic disease. Methods: This study was performed on a clinical 1.5 Tesla scanner using a gradient strength of 30 mT/m and the phased array spine coil. A cadaver was examined to optimise a magnetic resonance imaging (MRI) protocol to evaluate atherosclerotic aortic wall disease. The acquired MR images were compared to gross specimens and histology. Subsequently seven patients who had undergone transesophageal ultrasound (TEU) with detailed assessment of the descending thoracic aorta were examined with MRI. The optimised protocol included untriggered and fat suppressed T{sub 2}-weighted turbo spin echo sequences and ECG-triggered and fat suppressed T{sub 1}-weighted spin echo sequences before and after iv administration of Gd-DTPA. Findings of the MR ...
When performing trenchless pipe renovation work - whichever process you use - the success of the job depends on the careful removal of all scale, sediments and rust from the innerwall surfaces. The VACUJET process - in which the pipe is cleaned with water at pressures of up to 2 500 bar using a technique jointly developed by Preussag Rohrsanierung GmbH and Fabex GmbH - meets all requirements. The equipment includes a mobile waste water treatment unit which is small enough to fit on a standard trailer. Despite its compact dimensions this plant is so effective that it can treat all the waste water generated during the high pressure cleaning jobs so that it is suitable for reuse in the cleaning process or for release into the sewerage system. (orig.) [Deutsch] Bei der grabenlosen Rohrsanierung, ganz gleich nach welchem Verfahren saniert wird, ist die sorgfaeltige Entfernung von alten Beschichtungen, Ablagerungen und Rost eine wesentliche Voraussetzung fuer den ...
The interdiffusion behaviour of MCrAlY-coats on polycrystalline and single-crystalline materials of a similar composition (IN 738 LC/SC 16)shows similar interdiffusion characteristics. TCF-tests, where stress is generated by temperature and sample geometry at the edges of a disk-shaped sample, show that it is possible to differentiate betwee crack resistance of coated and uncoated samples. This method is also suitable for screening tests with different coat thicknesses. Coating of the edge area must, however, be done with great diligence in order to prevent coat thickness variation as results would then not be reproducable. Contrary to TCF (thermal cycle fatigue) TMF-tests (thermal mechanical fatigue)allow to set the stress states that one wishes to test. This method is therefore well suited for testing under operating conditions.(orig.) [German] Im Rahmen dieser Arbeit wurde gezeigt, dass das Interdiffusionsverhalten von MCrAlY-Schichten auf polykristallinen bzw. ...
The ERICAM model (Environmental Risk Internalization through Capital Markets) includes the capital markets as a source contributing to the coverage of risks due to nuclear activites, thus enhancing the effectiveness and functions of the nuclear liability law. The model proposed will allow higher amounts for compensation and will increase financial security, flow of information, and efficient use of resources. The implementation of the model can be achieved on the financing side by issuing Nuke bonds, linking accident-specific options to government bonds. This will essentially increase the risk coverage compared to present means, and will be a pin-pointed addition to the existing layer system. There are three institutions proposed to act as mediators in the implementation of the model: A government authority to supervise the trade in Nuke bonds. Risk-bearing associations in oder to enhance the model`s efficiency, and to reduce transaction costs. Rating agencies that will reduce the ...
Purpose: Reconstruction of organ doses of selected organs and tissues from radiographic settings and exposure data collected during chest X-ray examinations of children of various age groups performed in Dr. von Hauner's Kinderspital (children's hospital of the University of Munich, DvHK) between 1976 and 2007. Materials and Method: The dosimetric data of all X-ray examinations performed since 1976 at DvHK were stored electronically in a database. After 30 years of data collection, the database now includes 305 107 radiological examinations (radiographs and fluoroscopies), especially 119 150 chest radiographs of all age groups. Reconstruction of organ doses in 40 organs and tissues in X-ray examinations of the chest was performed based on the conversion factor concept. Results: The radiation exposure of organs in projection radiography is determined by the exact site of the organs relative to the edges of the X-ray field and the beam direction of ...
Purpose: Reconstruction of radiation doses for the thoracoabdominal babygram and the abdomen X-ray from radiographic settings and exposure data acquired at Dr. von Hauner's Kinderspital (children's hospital of the University of Munich, DvHK) between 1976 and 2007; comparison of these dose values with values reported in the literature; recommendation of a reference dose value for the thoracoabdominal babygram. Materials and Methods: The data from all X-ray examinations performed since 1976 at DvHK were stored electronically in a database. After 30 years of data collection, the database now includes 305 107 radiological examinations (radiographs and fluoroscopies), especially 1493 thoracoabdominal babygrams and 3632 abdomen X-rays of newborns and young infants. With the computer program PAeDOS, a specific dose reconstruction algorithm was developed. Results: the entrance dose values of thoracoabdominal babygrams and abdomen X-rays in DvHK could be ...
Compared to the reference year of 1990, CO{sub 2} emissions of the Federal Republic of Germany have been curbed by about 12%, primarily as a result of industrial backfitting and pollution abatement measures accomplished in the industrial infrastructure of the new Federal Laender of Germany. Federal Government policy sticks to the previous commitment, to reduce carbon dioxide emissions by 25% by the year 2005. Current forecasts and scenarios of future greenhouse gas emissions show that only immediate adherence to a very stringent reduction policy might ensure that this ambitious goal will be achieved. In this context, any change of the baseline data and scenarios hitherto used for progonostic assessments is a crucial factor, so that the article here discusses the impacts of a change in the nuclear generation scenario, as recently ventilated by the German Federal Government, and expected effects on public power supply. (orig./CB) [Deutsch] Ausgehend von dem ...
About 25 years after the last edification of a new large high voltage institute at Technical University of Karlsruhe and about 10 years afte the edification of the test lab at Kaiserslautern University, the Brandenburg Technical University of Cottbus had the opportunity to design new high voltage test facilities from the very beginning on and to realize it in a very short time. To review the project from the first ideas followed by the planning and realization phase and the final commissioning of the technical equipment, this book should be a contribution to spred the experiences made among interested people and to demonstrate the actual technical possibilities. To ensure an international exchange of these experiences, all co-authors to the trouble to translate their participation's also to the English language. (orig.) [German] Etwa 25 Jahre nach dem letzten grossen hochspannungstechnischen Institutsneubau in der deutschen Hochschullandschaft an der TH Karlsruhe, bzw. 10 ...
Metal hydrode stores are used as fuel tanks in vehicles or as stationary stores of high-purity hydrogen. Equilibrium isotherms at low pessures were measured in order to validate the laws of Henry or Sievert for hydrogen uptake of the alloy Ti{sub 0.98}Zr{sub 0.02}V{sub 0.43}Fe{sub 0.09}Cr{sub 0.05}Mn{sub 1.5} (patented by Daimler Benz AG, code DB5800). The laws were to provide information on whether hydrogen uptake is atomic or molecular and on the conditions in which isothermal measurements are possible. (orig.) [Deutsch] Metallhydridspeicher werden als Kraftstofftank in Fahrzeuge oder als stationaere Speicher zur Bereitstellung von Reinstwasserstoff verwendet. Fuer diese Arbeit wurden die Gleichgewichtsisothermen bei kleinen Druecken vermessen, um die Gesetze von HENRY oder SIEVERT fuer die Wasserstoffaufnahme in der Legierung Ti{sub 0.98}Zr{sub 0.02}V{sub 0.43}Fe{sub 0.09}Cr{sub 0.05}Mn{sub 1.5} zu pruefen. Anhand dieser ...
Smooth and notched specimens of the bearing steel 100Cr6 (SAE 52100) in a bainitic condition were used to determine the S-N curves under tensile, torsional and combined in- and out-of-phase loading. In the area of high-cycle fatigue, crack initiation was most likely caused by inclusions like Titanium Carbonnitrides or Aluminium Oxides. A micro mechanical model for the crack initiation by inclusions was developed. Another model was developed to describe the influence of these inclusions on the lifetime. A weakest-link model, using the statistical distribution of inclusions and surface flaws, was used to describe the endurance limit. (orig.) [German] Es wurden Woehlerlinien unter Zug-Druck-, Torsions- sowie kombinierter phasengleicher und phasenverschobener Zug-Druck- und Torsionsbelastung fuer glatte und gekerbte Proben des Stahls 100Cr6 (SAE 52100) im bainitischen Zustand erstellt. Im Bereich der Langzeitermuedung gingen die Risse meistens von nichtmetallischen ...
In rare cases, large adrenal masses with a suspicion of malignancy exhibit tumor extension into the adrenal vein and inferior vena cava. When planning surgery, the relationship of the extension to the inferior vena cava is of decisive improtance. We describe in two cases on the detection of a tumor thrombus in the inferior vena cava arising from a malignant adrenal mass by means of MR angiography (TOF, coronary 2D GRE images [FLASH], 3 slices acquired during 15 second apnea). The angiograms correlated well with the results of DSA venacavography and with the intraoperative findings. Thus, MRA has been demonstrated to be suitable for the certain proof of a venous tumor thrombus not only in cases of renal cell carcinomas but also in cases of malignant adrenal masses. The method should be applied whenever there is evidence of a venous involvement in the adrenal MR images. (orig.) [Deutsch] Grosse malignomverdaechtige Nebennierentumoren zeigen in seltenen Faellen eine Tumorausdehnung in die ...
The precipitation of heavy metals as hydroxides is the standard technique for the decontamination of waste water streams polluted by these elements. On the other side, progress in research has been made concerning the biosorption onto dead biomass and bioprecipitation supported by physiologically active bacteria. As the aim of this study, a flexible strategy has been envisaged cleaning a waste water with definite heavy metal load underlying the process mentioned above. Suitable bacteria were enriched and the process was tested in a technical plant. As result, a very high efficiency of heavy metal elimination has been found. The field of application covered by the acquired process is identical with the whole range of the waste water streams polluted by heavy metals. In addition, a second stage may be necessary if there are any further contaminants to be removed. (orig.) [Deutsch] Bei der Reinigung von schwermetallhaltigen Abwaessern ist der derzeitige Stand der ...
Purpose: The determination of tumor volume in ocular tumors is very important for the planning and success of radiation therapy. This study uses an animal model to evaluate the accuracy of MR-based volumetry of ocular tumors. Materials and methods: In a total of 25 porcine eyes obtained from the slaughterhouse, ocular tumors were produced by injecting a mixture of hand creme and Gd-DTPA under ophthalmoscopic guidance. The injected volume varied between 0.05 ml and 2.7 ml. The eyes were examined with a 1.5 Tesla scanner and a 4 cm circular surface coil especially developed for ocular MRI. After data transfer to a separate workstation, volumetric analysis was carried out by three independent radiologists using semiautomated software. The determined volume was compared with the injected volume. Results: Of the 25 prepared porcine eyes, 23 were suitable for volumetric analysis. The injection of the mixture of hand creme and GD-DTPA produced two different types of tumors. ...
Aim: Treatment of carcinoma of the uterine cervix by remote afterloading brachytherapy has been accompanied with new isotopes having dose rates different from the classical low-dose rate (LDR) radium source. The dose rate conversion factor from LDR to high-dose rate (HDR) found to be around 0.54 in most studies. As regards medium-dose rate (MDR) brachytherapie, the published data are very few and the experience is still short. In this study the experience of Osaka University Hospital with micro-HDR-Selectron and Selectron-MDR, as a preliminary report of the clinical trial, is presented. Results: The 3-year survival and loco-regional control rates for both modalities were nearly equivalent (62% and 67% for HDR and 68% and 74% for MDR)(totally 45 patients). The cumulative rectal and bladder complication rates were the same in both groups (29% at 3 years), with only 1 patient (MDR-group) developed grade 3 rectal and bladder complication. In this study, point A dose rate correction factor ...
This assessment is a feasibility study according to ISO 14024. It deals with the question whether an ecolabel is suitable for wood pellet heating systems and how concrete criteria for an ecolabel for wood pellet heating plants could be specified. The study begins with a comprehensive market analysis in order to identify possible plants for which an ecolabel would make sense. In the main part of the study, the environmental relevance of the chosen plants is analysed. For this analysis, plant manufacturers were interviewed and a comparison between wood pellet heating systems and heating systems which use gas, oil or wood was carried out. On the basis of this analysis, it was possible to derive a number of criteria which were discussed with company representatives and other experts in this field. As a result of this dialogue and the investigation process as a whole, the introduction of an ecolabel for wood pellet heating plants can be recommended. Wood pellet heating systems are ...
Objective: To determine the reproductibility of three-dimensional volume and thickness measurements of the knee joint cartilage with MRI in volunteers. Methods: The knees of 7 healthy individuals (ages 23 to 58 yrs.) were sagitally imaged with a resolution of 2x0.31x0.31 mm{sup 3}, using a fat-suppressed FLASH-3 D sequence. The knee was repositioned in between replicate acquisitions, 6 data sets being obtained in each case. After semiautomatic segmentation and three-dimensional reconstruction of the cartilage, the thickness was determined independent of the original section orientation. The coefficient of variation for repeated volume measurements and the deviations of the maximal cartilage thickness values were calculated subsequently. Results: The mean variation of the cartilage volumes of the replicate measurements was 1.4% ({+-}0.8%) in the patella, 1.7% ({+-}1.5%) in the femur, 3.0% ({+-}1.2%) in the medial tibial plateau and 3.5% ({+-}2.0%) in the lateral tibial plateau. The ...
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 ...
This feasibility study of the uve Institut fuer Technische Chemie und Umweltschutz GmbH discusses the scientific and technical fundamentals of a catalytic process for complete removal of organic pollutants (PAH, H-HC, PCB, phenols, nitro-aromatics and organometallic compounds, e.g. from polluted soil and groundwater) by thermal-catalytic cracking and conversion into simple gases. The process is based on the catalytic reaction of the hydrocarbon compounds with water vapour in the temperature range of 700-900 degrees centigrade. The resulting gas mixtures consist mainly of hydrogen, carbon monoxide, carbon dioxide and methane which can be used as fuels, e.g. for heating or in gas engines. The process is an alterntive to combustion. It is therefore well suited whenever the pollutant to be removed is already mixed with water or water vapour and wherever in-situ removal would be too great a hazard. [Deutsch] Die vorliegende Machbarkeitsstudie aus dem uve Institut fuer Technische Chemie und ...
The ECOTEC is a mass-efficient gasoline DOHC 4-valve per cylinder engine with balance shafts, chain driven camshafts and roller finger followers with hydraulic lash adjusters for valve actuation. It has lightweight aluminium components such as camcover, cylinder head, cylinder block, lower crankcase and structural oil pan. Other features include composite intake manifold and a coil-on-plug ignition cassette. The ECOTEC combustion system and engine architecture are optimized for low engine out and tail pipe emissions. It also includes several designed-in 'green' features for environmental benefits. The product design, development and validation process drew upon the best knowledge and practices available worldwide both inside and outside General Motor. The manufacturing systems were also designed by leveraging the best available knowledge around the world resulting in implementation of world class processes and error proofing to achieve the competitive edge in product ...
Normally, the alloy NiMo28 is used in the solution annealed and quenched condition in which it has a face centred cubic matrix structure. The matrix of the material is supersaturated with molybdenum and, at temperatures above 800 C, has a tendency to form intermetallic precipitates such as the Ni{sub 4}Mo-ordered phase leading to the embrittlement of the NiMo28-ordered phase leading to the embrittlement of the NiMo28 alloy during hot working. For this reason, the aim of these investigations was to optimise the alloy by reducing its tendency to embrittle. The TEM-analyses carried out served to investigate the precipitation of the material as a function of its iron content after ageing at 700 C. The change in hardness and in the lattice constants of the NiMo28-specimens with iron content were also determined. To improve the hot working properties of this material it is recommended that the iron content be kept to about 3.2 mass % in order to reduce the tendency of the alloy to ...
In comparison to deterministic criteria, probabilistic reliability indices like interruption frequency and unavailability give a more differentiated insight into reliability in an electrical energy network. One possibility for network planning based on these indices is the definition of limits for customer nodes, another is the monetarisation of reliability in terms of interruption costs. Because of numerous disadvantages, interruption cost methods could not up to now win broad recognition in network planning in Western Europe. A more recent method for the monetarisation of reliability circumventing most of these disadvantages is the insurance system. In this system the customer selects a tariff class in an insurance system, and the utility reimburses its customers in the case of an interruption. In its first section, the paper describes a method for the flexible and realistic optimisation of MV networks. This method based on Genetic optimisation is able to integrate probabilistic ...
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 ...
Parallel imaging and echo sharing techniques have markedly reduced the acquisition times for MRI of large volumes. Dynamic 2 and 3-dimensional data sets of the chest with high temporal resolution (up to 10 images/s with single slice and 2 volume/s) allow an analysis of respiratory motion of the lungs and tumors. Time-resolved 2D series in preselected planes can be used to observe respiratory motion during free breathing or after respiratory commands, e.g. to exclude chest wall invasion by a tumor or for diagnosing impairment of respiratory mechanics. Time-resolved 3D-series (4D-MRI) allow monitoring of the spatial displacement of the lungs and tumors as a whole volume. Present limitations such as an overestimation of tumor size and an underestimation of displacement due to a limited temporal resolution are expected to be overcome with further technical developments. However, 4D-MRI already appears to be the appropriate tool to select patients for motion-adapted radiotherapy. In ...
Maintenance of power stations so far operated on the concept of using or extending the expected service life of a machine or plant as far as possible in order to avoid early and costly replacement. This was done by means of time-oriented maintenance, inspection and repair, otherwise called preventive maintenance. A European study on maintenance methods totals the cost of these measures at between 140 to 200 billion DM. One way of reducing these costs is 'predictive maintenance'. Estimated savings are about 8 percent or between 12 and 16 billion DM per year. Predictive maintenance identifies irregulaties of machine parts at an early point in time by means of condition monitoring and can help to cut costs: unplanned repairs can be avoided; repairs can be fitted into production schedules; production will not be disturbed to to unforeseen repairs, optimised spare part warehousing helps to cut costs. Predictive maintenance aims at keeping availability high, give maximum ...
The paper presents fundamental studies on natural biosorption to algae of heavy metals. The investigations were carried out by TU Berlin University in a special research project (Sfb 193, 'Biologische Behandlung industrieller und gewerblicher Abwaesser'). The chlorophyceae C. vulgaris was used as reference alga, and 38 further algae were analzyed with regard to their sorption characteristics for lead, cadmium, nickel and zinc. The most effective algae were the chlorophyceae C. salina, the cyanophyceae S. hofmani and L. taylorii. The biosorption characteristics of C. salina and L. taylorii were investigated in detail. L. taylorii was found to be exploitable successfully in a technical process, so the investigations were extended to include copper. Knowledge about the chemical processes of biosorption is important for any attempt to modify the biosorption characteristics. Experiments on the incorporation of additional functional groups in the cell wall polysaccharides ...
The measuring series was performed from November 1991 through April 1992 in seven drinking-water conditioning plants of the Fichtel mountains area in the north-eastern part of Bavaria, and the results revealed as an annual average a dose of about 1 - 40 WLM. The area of interest is a drinking-water catchment area where the ground water and other water resources include waters particularly rich in radon content, which explains this relatively high dose range. This is why comprehensive, specific local and long-term mearurements were carried out in order to assess the occupational radiation dose in the drinking-water conditioning plants, taking as a model site the conditioning plant of the municipal utilities of Hof in Weissenstadt. These more specific measurements were performed by the Technical Inspectorates (TUeV) of Bavaria and Saxony and the isotope laboratory of Georg-August University of Goettingen in mid-April 1994 (Goettingen University, TUeV Saxonia and Bavaria) and from June ...
Introduction: The goal of this study was to compare contrast-enhanced T1-weighted Flash and Turbo-Flash sequences with conventional spin-echo sequences as a basis for planning high-precision radiotherapy. Methods: A total of 25 consecutive patients with different intracranial tumors and a disrupted blood-brain barrier were studied. T1-weighted Flash, Turbo-Flash and conventional spin-echo images were evaluated after controlled 30-s infusion of 0.1 mmol/kg body weight of Gd-DTPA. The evaluation of the three sequences included the measurement of the signal- and contrast-to-noise ratios, the visual inspection of the tumors and artifacts, and the measurement of tumor size. Results: The signal- and contrast-to-noise ratios were significantly (P<0.05-0.01) lower for Flash and Turbo-Flash than for conventional spin-echo sequences. However, visual inspection of the contrast-enhancing tumors revealed in 23 and 24 of 25 lesions of Flash and Turbo-Flash images, respectively, good or very good ...
Purpose: For planning the therapeutic strategies and estimating the prognosis in esophageal cancer, N-staging is very important. To date, MRI still is of minor importance as imaging modality of the mediastinum despite promising developments in the past, like ECG-gating or 'averaging' sequences, e.g. LOTA (Long-term averaging), which facilitate mediastinal and thoracic MR-imaging. In a prospective approach, the value of MRI based N-staging was examined with respect to LOTA-sequences. Material and Methods: Within from weeks prior to esophagectomy, standardized MRI of the esophagus was performed in 15 patients (10 squamous-cell-carcinomas and 5 adenocarcinomas) using a 1.5 T whole body scanner. Imaging quality was classified based on depiction of aortic wall or tracheal wall layers. Criteria for malignant infiltration were a diameter of more than 15 mm or a round appearance of a lymph node together with GD-DTPA enhancement. All data were blinded and separately read by ...
Main topic of the project was the manufacturing of highly efficient GaAs-solar cells and the fabrication of concentrator cells. During this process significant progress was made with the material preparation, the solar cell technology and the material and process characterisation. This succeeded in the following efficiencies: - GaAs solar cell made by MOVPE technology: 22.9% on 4 cm{sup 2} (AM1.5g) - GaAs solar cell made by LPE-ER process: 22.8% on 4 cm{sup 2} (AM1.5g) - GaAs concentrator solar cell made by LPE-ER process: 24.9% at C=100xAM1.5d - GaAs concentrator module with fresnel lenses: Module efficiency 20.1% (under irradiation of 793 W/m{sup 2}). Another main focus was the epitaxy of GaAs on Si substrate. Two different approaches were investigated. Together with the cooperation partner ASE, Heilbronn a selective growth technology was developed that led to a decreased crack formation. By a simultanous optimization of the other epitaxy and process parameters, the efficiency was ...
The quantitative measurement of carbon concentration-distance curves serves as fundamental prerequisite for the evaluation of rim zone properties connected with decarburisation processes in material science. This was shown in part 1 of the present work with two samples from through-hardenable rolling bearing steel 100Cr6 (SAE 52100) austenitised in different oxidising atmospheres by position dependent determination of hardness, residual stresses, and X-ray line broadening ({l_brace}211{r_brace} {alpha}'-Fe diffraction line). In practice, it is important to predict carbon concentration-distance curves under prevailing heat treatment conditions or to conclude conversely from profile measurements. Based on a refined kinetics model of a diffusion-controlled process, part 2 therefore presents a simulation tool developed by means of the finite element method (FEM). Apart from the concentration dependence of the diffusion coefficient, it also considers the decarburisation induced ...
In technical combustors, flow and combustion processes inside the combustion chamber determine the design and also the safety of the plant. A modelling technique was developed at TU Dresden which comprises both numerical simulations and experimental data and thus achieves a high degree of transparency in its visualisation of the processes inside the combustion chambers under investigation. With the experience gained, numerical models of commercial simulation software (FLUENT, CFX) can be validated by measured values, and potential applications of the programs can be investigated. The first stage of experimental modelling consisted in isothermal (cold) modelling in consideration of flow-relevant similarity characteristics. In the reactive, non-isothermal models, the fuel/air ratio and temperature conditions inside the original combustion chamber were modelled as well. In order to obtain detailed data on the combustion conditions at the burner, measurements were made on a separate ...
Purpose: The nint version of the licensing regulation for medical doctors (Approbation Regulation (AR)) sets a benchmark in terms of practical experience, interdigitation of preclinical and clinical studies, interdisciplinary approach, economic efficiency, independence of students, added new teaching and learning modalities, and ongoing evaluation of the progress of the medical students. It is the aim to implement these major points of the AR in a model course for diagnostic radiology and radiation protection within the scope of the Virtual University of Bavaria and test them in practice. Materials and Methods: In cooperation with residents and board certified radiologists, students developed the virtual course 'Web-Based Training (WBT) Radiology' in diagnostic radiology and radiation protection for students in the first clinical semester. A representative target group taken from the student body was asked about the options to get access to the World Wide Web ...
To permit an assessment of the system presented in this paper the data collected up to this point should be complemented by further experience with its practical use in electromobiles and the recovery of zink and the electrolyte. To this end the system is to be tested in electromobiles in 1995 and 1996. If there are no serious problems in the course of these tests and the above-mentioned estimates on economic efficiency are confirmed, then there is much to be said for a large-scale trial of these battery systems in electromobiles in the framework of a pilot project in Karlsruhe. Because of the infrastructure required for recharging, such a project should first be carried out in cooperation with fleet operators. As the recharging technique employed is so simple as to require no great investment and cost-effectiveness should already be achievable with a few tens of vehicles, one can conceive of a whole variety of applications in cooperation with public utilities, municipalities, and ...
Under the repository storage conditions of Eram and Konrad, waste packages designed for permanent storage must not contain or release freely mobile liquids, except for the minimum residues attainable by reasonable efforts or unavoidable. In accordance with a directive issued by the German Federal Ministry for the Environment (BMU), waste conditioning must be carried out so as to minimize waste volumes and, if possible, on the site where the waste arises. Liquid waste is conditioned most effectively by drying. At the present time, various different processes for drying liquid waste are employed as reflected by the state of the art: The Robe process; roller drying; the RDA process; Favorit; in-drum drying; and HPA liquid waste drying with make-up feed. The HPA process offers these advantages: Drying under atmospheric conditions, which means high level of dryness (freely mobile and releasable water is removed); the residual water content is 10%; isothermal drying by hot air, which ...
A cooperative effort of the Center for Solar Energy and Hydrogen Research (ZSW) and Phototronics Solartechnik GmbH (PST) aimed at the transfer of highly efficient solar cells developed on a laboratory scale, to large-area thin-film solar modules suitable for production. This work was based on research and development at the Institute for Physical Electronics (IPE) of Stuttgart University and ZSW on one hand, and on the know-how of PST in regard to large-area module fabrication on the other hand. The various thin-film layers of the cells and modules comprize molybdenum as rear contact, copper-indium(gallium)-diselenide (CIGS) as absorber material, the combination of cadmium sulphide (CdS) and ZnO as window layer. To produce these layers on large areas (30x30 cm{sup 2}), equipment was constructed and procedures were developed. Monolithic series connection of cells, used in other thin-film technologies, was studied and optimized by suitable patterning procedures, such as laser-scribing, ...
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 ...
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) ...
The transport-relevant basic data recorded within the framework of a federation-wide transport data survey made in 1986 are the best-founded source at present for determining the transport volume of other radioactive materials in different economic areas of the Federal Republic of Germany. Due to the high recording rates, a sufficiently complete survey can be provided in particular with regard to the transport volume (e.g.transports/consignments/cargos, transport distance) - with the exception of transport by ship - for the ranges of application in reserach, medicine and technology. However, as regards the radiologically relevant basic data and transport modalities, the information supplied by the transporting agencies is incomplete. A table gives a comprehensive survey of type and scope of the transport volume of other radioactive materials in the Federal Republic of Germany (excluding the GDR) for transport by road, rail and air. The table also includes data on the dose rate of ...
After 3 years of construction the trial run of the heating power station HKW 2 ended in November 1997 on time. No extraordinary damage occured during construction, assembly or commissioning. The plant has been operating according to schedule since November 1997. A brief inspection carried out in the summer of 1998 in order to assess warranty claims showed no damage to any part except one valve. Experience shows that all aforementioned activities were necessary. The paper reports about success and negative experience. Certification according to DIN EN ISO 9000ff., however, affords to guarantee of high-quality construction. Builders of such plants therefore need to set up their own quality assurance centre and ensure its technical competence. If necessary,additional experts should be called in.Quality assurance costs for HKW 2 came to about 0.5-0.6 percent of total costs. In view of the success and long life of this investment these expenses are more than justified. (orig.) [German] Nach ...
Purpose: In an experimental study, the correlation between the trabecular bone density of the different regions of the proximal femur and the fracture load in the setting of femoral neck fractures was examined. Methods: The bone mineral density 41 random proximal human femora was estimated by single-energy quanitative CT (SE-QCT). The trabecular bone density was measured at the greatest possible extracortical volume at midcapital, midneck and intertrochanteric level and in the 1 cm{sup 3} volumes of the centres of these regions in a standardised 10 mm thick slice in the middle of the femoral neck axis (in mg/ml Ca-hydroxyl apatite). The proximal femora were then isolated and mounted on a compression/bending device under two-legged stand conditions and loaded up to the point when a femoral neck fracture occurred. Results: Statistical analysis revealed a linear correlation between the trabecular bone density and the fracture load for the greater regions, with the highest value in the ...
Court decisions available so far do not primarily consider the problems linked to the commissioning of an expert and his mandate, as well as the legal status of the commissioning of an expert as an administrative act which might be legally contestable. Thus there are at present no court decisions that would create legal certainty in matters of the act of commissioning a nuclear expert opinion. The current legal situation is such that an independent order for commissioning of an expert opinion in compliance with section 19 III AtG (Atomic Energy Act), which in general is given in response to the refusal of the facility operator to do so, can be independently contested on the basis of section 44 a, sentence 2 VwGO (Rules of Administrative Courts). The current practice of conflict-oriented, or nuclear power phase-out-oriented, implementation of the nuclear law poses a threat to our constitutional state and to our democracy. The supply of energy as a common good is of essential importance ...
Tribological performance of alumina and silicon carbide ceramics as well as of the hardened steel 100Cr6 for reference was studied during reciprocating sliding and cavitation erosion in isooctane as substitute of gasoline and in distilled water. It was the aim to characterize effects of surface finish of the specimens and the liquid media on friction, resistance to sliding wear and cavitation erosion. Sliding wear tests were run on the self-mated ceramics and ceramic/steel pairs under conditions of boundary lubrication using a laboratory tribometer with cylinder-on-plate geometry. Vibratory cavitation erosion tests were conducted according to ASTM G 32-92. High initial surface roughness of coarse ground specimens led to a distinct running-in period during sliding contact with a transition from high to low values of friction coefficient and wear intensity. Incubation time was reduced with increasing surface roughness in the cavitation tests. Depending on the materials investigated, the ...
Already in 1998, the city of Hanover, the Stadtwerke Hannover and six further cities of the region initiated the funding programme 'Hannover proKlim' for promoting energy-relevant modernization measures in domestic buildings. One year later, the social marketing campaign 'Haus-Partner Hannover / Der (H)Eissbaer'' was started, which addresses building owners in Hanover with the intention to induce them to action. The 'Energiepass Hannover' is another important instrument of the campaign. This report takes stock of the results achieved so far. [German] Beim Klimaschutz im Gebaeudebestand lassen sich in Hannover drei Ansaetze hervorheben, die parallel zueinander entwickelt wurden und die in besonderer Weise dazu beitragen, die CO{sub 2}-Emissionen im Gebaeudebestand zu reduzieren: Bereits 1998 hat die Landeshauptstadt Hannover gemeinsam mit den Stadtwerken Hannover und sechs weiteren Staedten der Region den Klimaschutz-Fonds ...
A comparative process can be shown for the design of combined fuel cell powerstations. It is worth noting that the output of a combined powerstation working reversibly is independent of the thermodynamic state of the cell, and only depends on the reaction and thermodynamic state of the environment. The potential efficiency of gas-fired combined fuel cell powerstations is estimated at 80%. The fuel cell proves to be an isothermal heat source and not an adiabatic fluegas generator. This applies generally for all combustion power processes. Compared with external reforming, the integration of the reforming in the whole process leads to distinct advantages in efficiency if the possibilities of using the waste heat of intermediate thermal power processes are fully exploited. The plant implementation with an SOFC gas turbine process shows that realisation of a relatively simple plant concept leads to efficiencies distinctly above 70%. The enclosure design is of central improtance for the ...
The paper addresses the major items of relevance to compensation for nuclear damage under civil liability law. The revision of the Vienna Convention deserves support as a contribution to enhancing the protection of those who suffered damage, and of the environment. The results of the revision will have an impact on the liability regimes in existing and future signatory states, and to some extent will also set the goals of a future reshaping of the Paris Convention, all the more since the Joint Protocol calls for harmonization of at least basic provisions of substantive law in the two Conventions. (orig./HP) [Deutsch] Es werden die wesentlichen Punkte dargestellt, die fuer die zivilrechtliche Praxis im Schadensfall von Belang sein koennten. Die Revision ist als Beitrag zu einem verbesserten Schutz Geschaedigter, aber auch der Umwelt zu begruessen und zu unterstuetzen. Die Ergebnisse werden sich auf die Rechtsordnungen der gegenwaertigen und zukuenftigen ...
In a case study of the River Lahn, Hessen, Germany, the ecological impact of effluents from sewage treatment plants was investigated. These emissions have a significant impact on the receiving water quality with ammonia, nitrite, phosphorus and the eutrophication as most important factors. Current legislation standards seem to be sufficent for the sanitation of the nitrogen load. The potential of phosphorus removal in sewage treatment plants however may not reach the demand for eutrophication abatement. Therefore, integrated and immission oriented strategies are required including in site measures of river restoration. (orig.) [Deutsch] An der hessischen Lahn wurde in einem mehrjaehrigen Forschungsvorhabens die Bedeutung von Abwasserereinleitungen aus Klaeranlagen hinsichtlich ihrer gewaesseroekologischen Relevanz untersucht. Wesentliche Belastungen beziehen sich auf die Parameter Ammonium, Nitrit und Phosphor sowie eutrophierungsbedingte Folgeerscheinungen. ...
Investigations show that nickel-based alloys (MAR M 247 CC, CM DS 247 L and CMSX-4) can be successfully brazened. Tensile tests of MAR M 247 CC samples brazened with foil brazing showed values comparable to those of the base material, some samples failed because of base material problems. Tests with powder mixes made up from commercial brazens and the base material CMSX-4 showed good wetting and a perfect microstructure similar to the base material. Tensile test values at RT (test temperature) and 850 degrees centigrade show pronounced scatter. Tensile tests at RT and 850 degrees centigrade are used to optimse brazing cycles for the types of brazen used (temperature, time). (orig.) [German] Die Untersuchungen haben gezeigt, dass es moeglich ist, Nickelbasislegierungen (MAR M 247 CC, CM DS 247 LC und CMSX-4) erfolgreich zu loeten. Die im Zugversuch erhaltenen Festigkeitswerte der mit folienfoermigen Lot geloeteten MAR M 247 CC Proben erreichten Werte nahe der Festigkeit des ...
Clinical information is indispensable for swift and cost-effective clarification of diseases of the larynx. While quality clarification of neurological changes in the area of the posterior cranial fossa and in the course of the vagus nerve as a cause of glottis malfunction is possible with MRI, localized disease of the larynx can more effectively be assessed with low-artifact CT. In the particularly difficult assessment of the post-operative larynx, a recurrence can be diagnosed only after a baseline study has been carried out after the end of therapy. With knowledge of the pretherapeutic findings, the findings immediately post-therapy, and the operation technique used, the optimal CT examination, which can be carried out quickly, will be able to provide more information about recurrence. (orig.) [Deutsch] Zur schnellen und kostenguenstigen Abklaerung von Erkrankungen des Larynx ist die klinische Information unabdingbar: Wenn neurologische ...
The thesis explains the development of a mass spectrometerical isotope dilution analysis (MS/DA) for determining trace amounts of Tc. The Tc-97 isotope has been prepared by in-core irradiation of Ru of natural isotopic composition, and used as the indicator isotope. For separation of Tc-97 from the Ru matrix, a method has been developed to quantitatively separate Tc-97 from a high Ru surplus. For determining the isotope ratio for the MS/DA, a mass spectrometrical measuring technique has been found which allows reproducible measurement of the Tc-99/Tc-97 isotope ratio. Positive and, for the first time, also negative thermoionisation has been used as a method of selective ionisation of Tc. The applicability of the MS/DA for Tc trace analysis has been verified using two Al foils doped with Tc-99 or Mo-98, respectively. These have been irradiated in a nuclear reactor, the irradiation of Tc-99 yielding Ru-100, and irradiation of Mo-98 Tc-99. The determination of the elements Ru and Mo in ...
The spent fuel management concept of direct ultimate disposal is compatible in its fundamental features with the law of the European Community. This applies to a national law prohibiting spent fuel reprocessing and the handling of plutonium in Germany, imposing restrictions on exporting spent fuel assemblies and importing plutonium and reprocessing remnants, and on power plant operators to employ reprocessing services abroad. Also, a nuclear power phase-out decided by the German government would in principle not mean a breach of the EURATOM treaty. (orig./HP) [Deutsch] Als Alternative zur geltenden Rechtslage werden im Deutschen Rundestag Aenderungen vorgeschlagen, die das Entsorgungskonzept der direkten Endlagerung - d.h. ein Verbot der Wiederaufarbeitung von Brennelementen aus deutschen Kernkraftwerken auch im europaeischen Ausland - vorschreiben und einen ``Ausstieg`` aus der Kernenergienutzung anordnen. Vor dem Hintergrund einer Analyse der ...
Buildings in the USA are commonly not perceived as energy efficient and sustainable. Considering this, it comes as a surprise that the LEED (Leadership in Energy and Environmental Design) certification system is leading the process to certify ''Green Buildings'' despite the broad range of certification systems in countries such as BREEAM in England, CASBEE in Japan, HQE in France, Green Star in Australia, and most recently DGNB in Germany. International companies are pursuing the LEED certification due to its worldwide applicability - over 20,000 buildings in 76 countries are currently registered. (Abstract Copyright [2009], Wiley Periodicals, Inc.) [German] Die USA sind nicht gerade fuer oekologisches und energieeffizientes Bauen bekannt. Umso erstaunlicher ist es, dass das LEED-Zertifizierungssystem (Leadership in Energy and Environmental Design) neben anderen landesspezifischen Systemen wie z. B. BREEAM in England, CASBEE in Japan, HQE in ...
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. ...
The direct injection Diesel engine with its specific fuel consumption of about 200 g/kWh is one of the most efficient thermal engines. However in case of relatively low CH- und CO-emission the soot- and NO{sub x} concentration in the exhaust gas turns out to be a problem with respect to the legislation on emission limits. At the department of piston- and turbo-machines of the Trier University of Applied Sciences, a single-cylinder testing engine with two injection-systems (fuel and water) has been developed. This engine has been constructed to analyse the effect of stratified water-injection on the soot- and NO{sub x} emissions of exhaust gases of a Diesel engine. (orig.) [German] Der Dieselmotor mit Direkteinspritzung stellt mit spezifischen Kraftstoffverbraeuchen in der Groessenordnung von 200 g/kWh eine der wirtschaftlichsten thermischen Kraftmaschinen dar. Bei relativ niedrigen Kohlenwasserstoff- und Kohlenmonoxid-Emissionen erweist sich die Russ- und ...
Experiments for lifetime prediction of the first wall are being carried out within the framework of the European fusion reactor programme. Defects such as notches and cavities may develop in the first wall and may initiate under cyclic thermal stress cracking processes which may reduce the service life of the material. For examination of crack growth, specimens with defined initial notches were prepared and subjected to cyclic thermal loads. The paper shows that the eddy current method is suitable for detecting and revealing the crack growth processes even under conditions of complex geometry, as e.g. cracks in inner bores. The experiments indicated particularly susceptible, critical spots in the first wall and yielded crack growth rates of use for lifetime calculations. (orig./CB) [Deutsch] Im Rahmen des europaeischen Fusionsreaktorprogramms werden Untersuchungen zur Lebensdauervorhersage der Ersten-Wand durchgefuehrt. Die Erste-Wand kann Fehler in Form ...
Isothermal reaction experiments were performed in the temperature range of 1000 - 1300 C in order to determine the chemical interactions between Zircaloy-4 fuel rod cladding and Inconel-718 spacer grids of Pressurized Water Reactors (PWR) under severe accident conditions. It was not possible to apply even higher temperatures since fast and complete liquefaction of the components occurred as a result of eutectic interactions during heatup. The liquid reaction products formed enhance and accelerate the degradation of the material couples and the fuel elements, respectively. Only small amounts of Inconel are necessary to liquefy large amounts of Zircaloy. Thin oxide layers on the Zircaloy surface delay the beginning of the chemical interactions with Inconel but cannot prevent them. In this work the reaction kinetics have been determined for the system: as-received and pre-oxidized Zircaloy-4/Inconel 718. The interactions can be described by parabolic rate laws; the Arrhenius equations for ...
The further optimisation and improvement of the efficiency of internal combustion engines require the realisation of new technologies leading to a distinctively faster warm-up behaviour of the coolant and lubricants as well as of the engine components after a cold start. In order to achieve reduced fuel consumption and exhaust gas emissions with the help of heat management, the design criteria of innovative cooling systems need to be reflected and adapted to future requirements. The use of intelligent components within the cooling system, such as the 'Stand Alone Rotary Valve' as a thermostat's substitute or the use of coolant pumps with a rotary valve integrated into the pump's inlet chamber, offer new ways to realise in a decisively quicker and more flexible way the appropriate heating up and cooling down procedures at varying driving conditions. A description of both of the intelligent components for the cooling system is given in this paper. The ...
In an epidemiological study of the somatic late effects risk following incorporation of a short lived {alpha}-emitter, 1473 ankylosing spondylitis patients treated with repeated intravenous injections of {sup 224}Ra in the years 1948 - 75, have been observed in the GSF. The usual therapeutic plan consisted of a total of 10 - 12 injections of 1.036 MBq (28 {mu}Ci) of {sup 224}Ra each, given at weekly intervals; this would result in an cumulative {alpha}-dose of 0.56 - 0.67 Gy to the marrow-free skeleton of a 70-kg-man (standard man). These patients have been followed together with a control group of ankylosing spondylitis patients not treated with radioactive drugs and/or X-rays. Until May 1993 (mean follow-up time 19.9 yr), 595 patients of the exposure group and 722 patients of the control group have died, causes of death have been ascertained for 578, resp. 668 patients. Among others we observed in the exposure group 10 cases of leukaemia (vs. 2.7 - 2.8 cases expected, p < 0.001) ...
Objective: To determine the efficacy of a covered stent prototype designed for protected carotid angioplasty to reduce cerebral embolization. Material and Method: The covered stent tested is made of nitinol, coated with a polyurethane membrane (MembraX{sup TM}; porous size 80 {mu}m). In a bench-top model (flow-rate 650 ml/min, pulsatile flow [dicrote] 123 Pulses/min, pressure 100/60 mm Hg [mean pressure 80 mmHg]) with inserted human carotid (n=6) stent implantation was performed (8/32 mm). Passed particles (mg) were determined in the effluent of a 100 {mu}m filter prior to intervention, after stent deployment and after final dilation (5 mm). Results: When stenting carotid arteries obtained from human cadavers, the highest rate of particle embolization was measured while crossing the lesion with the delivery device (6,8 mg; for all p<0,05), embolization after additional balloon angioplasty and particle rates measured in the effluent filter prior covered stent placement were ...
Pr{sub 2}[Mo{sub 2}C{sub 3}] was obtained by arc melting of the elements followed by annealing at 1500 C in arc welded and sealed Mo-ampoules. The compound was characterised by chemical analyses, X-ray diffraction and metallography. The crystal structure (monoclinic, P2{sub 1}/c, Z = 4, a = 597.99(10) pm, b = 665.15(11) pm, c = 1185.60(19) pm and {beta} = 111.631(5) ) represents a new structure type containing a three dimensional polyanion {sub {infinity}}{sup 3}[(Mo{sub 2}C{sub 3}){sup 6-}] with Molybdenum(III) in a distorted tetrahedral coordination by carbo-ligands. Tetrameric building-blocks, Mo{sub 4}C{sub 10}, of edge sharing MoC{sub 4}-tetrahedra are arranged to form layers running parallel to (100). The layers are interconnected along [100] by sharing common apices of the MoC{sub 4} tetrahedra. The coordination polyhedra around praseodymium represent distorted (PrC{sub 5})-arrangements (mono capped tetrahedra and square pyramids). The metal atoms together form a distorted motif ...
The role of high-resolution computed tomography (HRCT) and magnetic resonance imaging (MRI) in the diagnosis of preoperative and postoperative complications caused by acquired cholesteatomas will be described in this paper. The pre- and postoperative imaging of the temporal bone was performed with HRCT and MRI. HRCT and MRI were performed in the axial and coronal plane. MRI was done with T2 weighted and T1 weighted sequences both before and after the intravenous application of contrast material. All imaging findings were confirmed clinically or surgically. The preoperative cholesteatoma-caused complications depicted by HRCT included bony erosions of the ossicles, scutum, facial canal in the middle ear, tympanic walls including the tegmen tympani, and of the labyrinth. The preoperative cholesteatoma-caused complications depicted by MRI included signs indicative for labyrinthitis, and brain abscess. Postoperative HRCT depicted bony erosions caused by recurrent cholesteatoma, bony defects ...
Poly-Lactic-Acid (PLA) was evaluated for coating of vascular endoprotheses in the treatment of experimental arterio-venous-fistulae (AVF). Bilateral carotid-external jugular AVF were created in 5 adult dogs. 7 PLA coated nitinol stents were placed via a transfemoral approach covering 5 AVF. The contralateral AVF remained untreated. Angiography was performed immediately after stent placement, at weeks 1 and 3 and at months 3, 6 and 9. All grafts were removed and underwent histologic examination. In 2 cases the occlusion of the AVF was successful, while misplacement occurred in 3 cases. Occlusion of the parent vessel was disclosed in 3 cases. Histologic examination revealed a mild inflammatory reaction with the presence of macrophages. There was no foreign-body reaction or fragmentation of the arterial vessel wall. PLA, which is a well-known biodegradable material, showed a good mid-term biocompatibility. Elastic mismatch of the non-elastic coating and the self-expandable nitinol stent ...
The fundamental recommendations of the ICRP issued in its publication of 1990 stipulate the general principle of performance of dose measurements at regular intervals in the field of diagnostic radiology, for the purpose of equipment performance checking and optimization of radiological protection. In response to this requirement, the Federal Ministry, in cooperation with experts and the competent supervising authorities, has issued an order to install dose-area-product meters in angiographic examination systems, imaging systems and fluoroscopic screen devices primarily used for examining infants and children up to the age of 12. This is done in response to reported cases of adverse effects of radiation exposure and the high priority given to radiological protection in the examination of infants and children. In 1992, an expert group was convened to discuss and elaborate instructions for including dose-area product measurement in the dosimetry activities in medical diagnostic ...
Purpose: Liposarcoma is the most common soft tissue sarcoma in adults. The purpose of the study was to correlate MR imaging features with the four ICD subclasses. Methods: 28 patients with liposarcoma were examined preoperatively on a 1.0 T MRI system, using spin echo sequences, gradient echo imaging and STIR sequences. In all patients, classification of the liposarcomas was made by histologic diagnosis (ICD-10-M-classification). Results: Well differentiated liposarcomas (9 patients) showed a number of MRI features consistent with lipoma (well defined mass high signal intensity (SI) on T{sub 1} images, low signal on T{sub 2} images, no or only little signal increase of tumour tissue after contrast material application, no necrosis). Not well differentiated liposarcomas (myxoid 14 patients, pleomorphic three patients, round cell two patients) revealed the largest part of the mass to be of low SI on T{sub 1}-weighted images. Only scattered fatty islands and septa (9 patients with myxoid ...
Patients with haemarthros of the knee were examined by MRI and arthroscopy to identify the bleeding source and to determine surgical or conservative therapy. A prospective study was performed on 120 patients who underwent MRI and arthroscopy, point lesions and bleeding sources were documented separately on a standardised form. Arthroscopy demonstrated a ruptured anterior cruciate ligament in 86%, meniscal tears in 55%, disruption of collateral ligaments in 17%, osteochondral lesions in 5% and tears of capsule or plicae in 13%. Disruption of cruciate ligaments caused haemorrhage in all but three cases. In contrast, only meniscal tears located very adjacent to the meniscal basement had bled. Those types of osteochondral lesions caused haemorrhage characterised on MRI by destruction of the subchondral plate and overlying cartilage. Severe lesions of the knee were diagnosed by MRI in 71% to 100%, slight lesions in 13% to 40% of the cases. Single, combined and bland lesions were accurately ...
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 ...
Functional imaging of the pharynx used to be the domain of cineradiography, CT and ultrafast CT. The development of modern MRI techniques led to new access to functional disorders of the pharynx. The aim of this study was to implement a new MRI technique to examine oropharyngeal obstructive mechanisms in patients with obstructive sleep apnea (OSA). Sixteen patients suffering from OSA and 6 healthy volunteers were examined on a 1.5 T whole-body imager (`Vision`, Siemens, Erlangen Medical Engineering, Germany) using a circular polarized head coil. Imaging was performed with 2D flash sequences in midsagittal and axial planes. Patients and volunteers were asked to breathe normally through the nose and to simulate snoring and the Mueller maneuver during magnetic resonance imaging (MRI). Prior to MRI, all patients underwent an ear, nose and throat (ENT) examination, functional fiberoptic nasopharyngoscopy and polysomnography. A temporal resolution of 6 images/s and an in-plane resolution of ...
Which imaging modalities are appropriate for the Differential diagnosis of Rheumatic diseases. MRI has far most the highest sensitivity and is unequaled in its brilliant presentation of Anatomy and Pathology. But it is sometimes forgotten, that this is at least in part the result of carefully selected sequences, dedicated to the expected result. In a method totally independent of any result, this should not be the case. In contrary this method should be highly standardised and regardless what will be the findings. This is true for Plain X-ray. It will be shown, that already the outer silhouette of the soft parts with different features of swelling, and differences in density and even more - defects or appositions of the bony silhouette in the majority of cases at least will allow to classify the patient for a group of diseases and in many cases will lead to a definite diagnosis. Differential diagnoses like Rheumatoid Arthritis versus Psoriatic Arthritis or simply but not always simple ...
Purpose: To evaluate the success rates of the implantation of stent grafts in the treatment of peripheral aneurysms. Materials and methods: in 13 patients with 15 aneurysms at the common iliac artery (n = 6), external iliac artery (n = 1), hypogastric artery (n = 2), femoral artery (n = 2) or popliteal artery (n = 4), implantation of dacron-covered nitinol stents was performed. The patients were followed up for three to 20 months (mean, 8.8 months) with intravenous digital subtraction angiography, CT or colour-coded Doppler sonography. Results: In all cases, the aneurysm was successfully occluded after stent implantation. In one case with a popliteal aneurysm, kinking of the vessel caused thrombosis of the stent. The stent was successfully reopened. The aneurysm however, had to be surgically treated 9 months later. The primary and secondary patency rates at 6 months were 93% and 100%, respectively. Conclusion: The method described might be an alternative therapy to surgery. There are ...
Objective: Optimization and testing of a high temperature combustion chamber for burning coal gas and conventional fuels natural gas or fuel oil. Coal gas is not available in such quantity for testing a full scaled combustion chamber. Therefore the design of the combustion chamber is based of experimental results from model tests and numerical solution procedures. Working program: (1) Analytical model for burning coal gas implemented in an existing computational fluid dynamics (CFD) code. (2) Three-dimensional calculations of a full scaled combustion chamber with a CFD code for flows accompanied by combustion and chemical reaction. (3) Improvement of measuring method for determination of flame temperature and concentration. (4) Temperature and concentration profil measuring in a full scaled combustion chamber by operating with natural gas or fuel oil. Results: An analytical model for burning coal gas was implemented in an existing two-dimensional CFD code. The model gave acceptable ...
This contribution provides an overview and imparts basic knowledge on pertinent technical developments in magnetic resonance imaging (MRI) of the liver: 3D sequences, respiratory triggering, parallel imaging, and 3 Tesla (3T). 3D sequences can be used as T1-weighted (T1w) sequences for analyzing dynamics of contrast enhancement or as T2w sequences for MR cholangiography. Consistent improvements in respiratory triggering make it possible to obtain good image quality on T2w scans even in patients unable to hold their breath. Parallel imaging as a universal technique to accelerate image acquisition is particularly appropriate for MRI of the liver, and it has been shown that the reduced acquisition time is not achieved at the expense of image quality. Further progress in MRI of the liver can be expected with use of the 3T systems, but hitherto irrelevant problems must still be solved. Overall the innovations presented here, applied alone or in combination, facilitate rapid, robust, and ...
The transversus perinei profundus muscle is a well known structure in found anatomical textbook. Fibres of this muscle are believed to form the so-called external urethral sphincter (musculus sphincter urethrae). Recently histomorphologic investigations have shown that there is no muscular connection between the musculus sphincter urethrae (external sphincter) and the muscle system of the pelvic floor. Furthermore, the external sphincter was found to be divided into parts: The transversely striated part (musculus sphincter urethrae transversostriatus) and the smooth part (musculus sphincter urethrae glaber). Similar to histomorphologic investigations, contrast-enhanced MR imaging has shown the musculus sphincter urethrae to be surrounded by fatty and connective tissue only. Neither in MRI nor in anatomical slices can any connection between the urethral sphincter and the muscle system of the pelvic floor be found. Thus, on the basis of the results presented in this work it is concluded ...
Purpose: Budd-Chiari syndrome is a fairly uncommon disease in Europe. This often leads to its late diagnosis. The syndrome is characterised by portal hypertension and splanchnic congestion due to obstruction of hepatic venous outflow. This paper describes the treatment of three patients with Budd-Chiari syndrome by interventional therapeutic techniques and discusses alternative treatment modalities. Patients and Methods: The first patient presented with veno-occlusive disease and was treated by the placement of a transjugular intrahepatic portosystemic stentshunt. The second patient showed an occlusion of the major hepatic veins. After percutaneous recanalisation, a stent was placed in the right hepatic vein which remained patent. The third patient had a membranous obstruction of the right hepatic vein which was treated by percutaneous balloon dilatation. Results: In all patients the clinical symptoms resolved completely after treatment and no complications were encountered. ...
This proceedings volume comprises 17 papers on the following subjects: Methane hydrates, compounds of gas and water; Compressed air stroage gas turbine power plants / Scheduled application for load levelling between varying wind power production and power demand; Modern pumped storage power stations in the GW range - the PSW Goldisthal example; Lead batteries - new developments and future applications; Alkaline battery systems for hybrid electric road vehicles; Lighium systems and their applications; Zinc/air cells; Hydrogen storage - metal hydride storage, compressed gas storage, LNG storage; Carbon nanofibres for hydrogen storage; Double-layer condensers - technology, cost, perslpectives; Supercondensers in motor vehicles; Superconducting magnetic energy stores; Flywheel storage - status report; Decentralized energy storage in the European integrated supply grid - the EU project DISPOWER; Intercontinental integration of power supply - perspectives of full-scale power supply on the ...
Low energy buildings promise significant energy savings and help climate preservation by cutting down on annual heating requirements to values below 70 kWh per m{sup 2} dwelling space. It is expected that low energy constructions will become the common standard by the year 2000 as a result of the forthcoming energy saving ordinance. For making the introduction and implementation of this standard successful, practical experience will be essential. For this reason, the state government of Hesse has supported respective pilot projects 1987. In 1989 the funding programme `30 low energy buildings in Hesse` has been established. Consecutively - between 1989 and 1993 - 29 buildings were erected. At first, the thermal quality of the crafted building construction including the ventilation systems was checked. Consecutively, energy consumption, indoor and outdoor temperatures were measured over a time span of several years. The experience of the inhabitants was surveyed. The `Institut Wohnen und ...
Purpose: {sup 31}P-MRS is used to assess the influence of sex and age on quadriceps muscle metabolism before and after exercise. Materials and Methods: 32 healthy volunteers (15 women, 17 men; mean age: 38{+-}17 yrs.) were examined by dynamic phosphorus-31 ({sup 31}P) magnetic resonance spectroscopy (MRS). In the magnet, the quadriceps muscle was stressed by an isometric and an isotonic form of exercise until exhaustion, respectively. Results: Resting conditions: With increasing subjects` age, the ratio {beta}-adenosine triphosphate/total phosphate decreased (r=-0.37; p=0.02). With increasing subjects` age, the ratios inorganic phosphate/phosphocreatine (r=0.79; p=5x10{sup -8}), phosphomonoester/{beta}-adenosine triphosphate (r=0.74; p=10{sup -6}) and phosphodiester/{beta}-adenosine triphosphate (r=0.62; p=10{sup -4}) increased. The pH was the only one of the evaluated spectroscopic parameters which showed a sex-dependence: Female subjects had a significantly lower pH (7.03{+-}0.02) ...
The agglutination of human platelets by ristocetin and von Willebrand factor was inhibited by aggregated immunoglobulin (Ig)G and by Fc fragments of IgG, but not by Fab, F(ab′)2 or...Full Text Available
Human Factor VIII/von Willebrand factor, purified by calcium citrate-cellulose chromatography and 4% agarose gel filtration was subjected to sodium dodecyl sulfate gel electrophoresis on gels containing...Full Text Available
In this article we obtain an alternative formulation of the von Mises type conditions for p-max stable laws in terms of generalized log Pareto distributions (glogPds). Relationship between the rate of convergence of extremes and the remainder terms in the von Mises type conditions is investigated. It is shown that the rate of convergence in the von Mises type conditions for p-max stable laws determines the distance of the underlying distribution function from a glogPd.
Objective: To evaluate the treatment of malignant biliary stenoses and occlusions using a new stent. Methods: In a prospective study, 25 patients with malignant obstructive jaundice were treated with SMART stents. The handling and the quality of stent expansion were documented. Stent function was assessed 2-4 days after intervention by cholangiography and laboratory tests. A follow-up was performed three months, after stent placement. Results: All lesions were treated successfully, with a total of 35 stents implanted. In 14 patients a further balloon dilatation was performed after stent placement (8-10 mm diameter/40-80 mm length). The mean serum bilirubin level decreased significantly from 11.6 mg/dl to 4.6 mg/dl after intervention (p<0.05). The follow-up showed a mean serum bilirubin level at 4.0 mg/dl. In 4 cases (16%) a further intervention (PTCD or stent) was performed. Six patients died due to tumor progression. The stents proved to be patent in 79% (n=15) of patients ...
Purpose: To report on the nephron-sparing, percutaneous ablation of a large renal cell carcinoma by combined superselective embolization and percutaneous radiofrequency ablation. Materials and Methods: A 5 cm renal cell carcinoma of a 43-year-old drug abusing male with serologically proven HIV, hepatitis B and C infection, who refused surgery, was superselectively embolized using microspheres (size: 500 - 700 {mu}m) and a platinum coil under local anesthesia. Percutaneous radiofrequency ablation using a 7F LeVeen probe (size of expanded probe tip: 40 mm) and a 200 Watt generator was performed one day after transcatheter embolization under general anesthesia. Results: The combined treatment resulted in complete destruction of the tumor without relevant damage of the surrounding healthy renal tissue. The patient was discharged 24 hours after RF ablation. No complications like urinary leaks or fistulas were observed and follow up CT one day and 4 weeks after the radiofrequency ...
Aim: Changes within the brain detected by MRI after chronic manganese poisoning raised the question whether morphological changes of the basal ganglia, particularly of the globus pallidus, could be detected after chronic occupational exposure to manganese dioxide. Results: No cases of parkinsonism were detected in clinical examinations or by other means. The mean manganese concentration in blood was 12 {mu}g/l (range: 3.9-23.3 {mu}g/l). In comparison to the upper reference value of 10 {mu}g/l, 42 workers (56%) had a higher body burden. A significant positive correlation between manganese levels in blood and the PI (indicated by T{sub 1}-shortening) was observed as well as between the CBI and workplace-specific exposure. Brain atrophy was not detected in any of the observed cases. Conclusions: Long-term exposure to manganese dioxide dust correlates with the Pallidum-Index in MRI scans. Although the MRI findings have no current clinical relevance for individuals, further studies are ...
Purpose: Measurement of the oscillating CSF flow in the spinal canal (SC) of healthy volunteers and in patients with post-traumatic syringomyelia (PTS) using an optimized MRI protocol as well as to determine whether stenosis induced velocity changes are detectable using MRI. Methods: In 68 healthy volunteers quantitative studies of CSF flow in the cervical, thoracic, and lumbar regions were performed. First, an optimized sequence was developed and tested in 19 volunteers using four different flow-encoding velocities (4, 8, 12, 16 cm/s). Secondly, the optimized sequence was employed in 49 volunteers to measure the different CSF patterns in the cervical, thoracic, and lumbar spinal canals (CSC, TSC, LSC). Part three of the study, in which patients with PTS are being examined is still underway. We measured the maximum velocity (cm/s), the pixel area (mm{sup 2}), and the stroke volume (ml/s). Using a flow model the velocities prior to and after compression with 5 different power levels ...
The obligations under international law to reduce transfrontier air pollution is discussed in five chapters from various aspects. Consequences for the European Communities are gone into in five further chapters. (orig./HP)
The report provides and overview of calculation models for the simulation of airflows and deals comprehensively with field and multi-zone models as well as the coupling of individual zone and multi-zone models. Examples of calculations are given. figs., tabs., refs.
In order to remove ash from coal, it is introduced into an aqueous ash removal solution, which contains nitric acid or citric acid and ammonium hydrogen fluoride. The coal without ash is then separated from the aqueous solution. According to the process, either finely ground coal is introduced into the ash removel solution or the coal with the solution is ground in a wet pulveriser.
PurposeAlthough the safety and feasibility of partial adrenalectomy in patients with von Hippel-Lindau syndrome have been established, long-term outcomes have not been examined. In this study we evaluate the recurrence and functional outcomes in a von Hippel-Lindau syndrome cohort treated for pheochromocytoma with partial adrenalectomy with a followup of at least 5 years. Materials and MethodsWe reviewed the records of patients with von Hippel-Lindau syndrome treated with partial adrenalectomy for pheochromocytoma at the National Cancer Institute. Demographic, germline mutation status, surgical indication, oncologic and functional outcome data were collected. Local recurrence was defined as radiographic evidence of recurrent tumor on the ipsilateral side of partial adrenalectomy. Patients ...
The regulation of blood vessel formation is of fundamental importance to many physiological processes, and angiogenesis is a major area for novel therapeutic approaches to diseases from ischemia to...Full Text Available
Turbine sets are inspected at their overhaul intervals throughout their operating lives. Using three examples, the present article describes the procedure in the inspection and assessment of steam turbines during overhauls and also deals with rehabilitation measures. In addition to the usual non-destructive tests and the recording of findings, computational life assessments are also considered. (orig.) [Deutsch] Turbosaetze werden waehrend ihrer Betriebszeit anlaesslich von Revisionen ueberprueft. Anhand von drei Beispielen wird in diesem Beitrag die Vorgehensweise bei der Pruefung und Bewertung von Dampfturbinen bei Revisionen und fuer Rehabilitationsmassnahmen dargestellt. Neben ueblichen zerstoerungsfreien Pruefungen und Befundaufnahmen erfolgten in Verbindung damit auch rechnerische Lebensdauerbewertungen. (orig.)
... XVIII, n. 1, p. 50-67. [2] G. Becker: Zeitskalenprobleme: jahreszeitliche Gangschwankungen von Atomuhren, PTB Mitteilungen 92 2/82, p. 105-113. ...
The brochure reports on the construction and method of operation of heat pumps: - Efficiency and temperature difference - output figure - circuit processes - saving of primary energy - monovalent and bivalent plants - absorber, earth collectors - heat recovery. (HW) [Deutsch] Die Broschuere berichtet ueber den Aufbau und die Wirkungsweise von Waermepumpen: - Wirkungsgrad und Temperaturdifferenz - Leistungszahl - Kreisprozesse - Einsparung von Primaerenergie - monovalente und bivalente Anlagen - Absorber, Erdkollektoren - Waermerueckgewinnung. (HW)
Zusammenfassung Der vom Bundesamt f?r Sicherheit in der Informationstechnik (BSI) entwickelte Ansatz des IT-Grundschutzes war bereits Gegenstand von Beitr?gen in der DuD. Inzwischen hat das ?Grundschutzhandbuch? Eingang in die internationale Standard-Familie ISO 2700x gefunden. Der Autor berichtet ?ber die Erfahrungen mit den ersten durchgef?hrten Zertifizierungen nach dem neuen ISO-Standard auf der Basis von IT-Grundschutz.
The ash of biomass fuels was analysed in order to identify its inorganic chemical characteristics. The experiments were carried out using different methods of extraction. The accuracy of the measurements was verified by comparative analyses using certified samples. The composition was shown to vary with the fuel type and ash fraction. In the case of arsenic and the toxic heavy metals cadmium, mercury and lead, accumulation factors of 1.4 to 43 were measured in the tissue filter ash. [German] Fuer die Bestimmung der stofflichen Eigenschaften von Biobrennstoffaschen werden neben der fuer die Ermittlung von Stoffbilanzen notwendigen Analyse der Gesamtgehalte, in Abhaengigkeit von der Zielsetzung und den gesetzlichen Vorgaben, unterschiedliche Extraktionsverfahren eingesetzt. Fuer die Gesamtgehaltsbestimmung wurden aus laborinternen Wiederholungsuntersuchungen sowie einem laborexternen Analysenvergleich Kenngroessen fuer die ...
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 ...
Tumours lesions of the temporal bone and of the cerebello-pontine angle are rare.This tumours can be separated into benign and malignant lesions. In this paper the CT and MRI characteristica of tumours of the temporal bone and the cerebello-pontane angle will be demonstrated. High resolution CT (HRCT) as usually performed in the axial plane are using a high resolution bone window level setting, coronal planes are the reconstructed from the axial data set or will be obtained directly. With the MRI FLAIR sequence in the axial plane the whole brain will be scanned either to depict or exclude a tumour invasion into the brain. After this,T2-weighted fast spin echo sequences or fatsuppressed inversion recovery sequences in high resolution technique in the axial plane will be obtained from the temporal bone and axial T1-weighted spinecho sequences before and after the intravenous application of contrast material will be obtained of this region. Finally T1-weighted spinecho sequences in high ...
The examples quoted show that damage is mostly due to faults of design and construction or faulty operation. The ever shorter development cycles, the further development of existing constructions and cost pressure owing to price slumps are very important in this context. Careful endoscopic inspections and monitoring and early identification of beginning damage helps to prevent major damage and follow-up damage. The causes of changing operational performance must be established as early as possible to prevent larger damages from being caused by continued operations.(orig.) [German] Die vorgestellten Schadenbeispiele zeigen, dass die Schaeden vorwiegend durch Auslegungsfehler und Konstruktionsfehler aber auch durch Bedienungsfehler verursacht wurden. Die immer kuerzeren Entwicklungszeiten fuer Neukonstruktionen und die Weiterentwicklung vorhandener Konstruktionen sowie der Kostendruck infolge des Preisverfalles sind hierbei von grosser Bedeutung. Weitherhin ist die ...
The goal of this project was to develop a new technology for preparing samples for transmission electron microscopy (TEM) on the basis of ion fine beam processing. For this purpose processes of ion-beam-assisted removal (sputtering), separation, sample handling and ion-beam-assisted chemical etching as well of system-inherent components were examined. As an alternative to a Ga-source a liquid-metal ion source based on a AuGeSi alloy was developed, characterised and used in the FIB 4400. [German] Aufgabe des Projektes war die Entwicklung einer neuen Technologie zur Probenpraeparation fuer die Transmissions-Elektronenmikroskopie (TEM) auf der Basis der Ionenfeinstrahlbearbeitung. Dazu wurden Prozesse der ionenstrahlgestuetzten Abtragung (Sputtern), der Abscheidung, des Probenhandling, des ionenstrahlgestuetzten chemischen Aetzens sowie systemeigener Komponenten untersucht. Als Alternative zur Ga-Quelle wurde eine Fluessigmetall-Ionenquelle auf ...
The research project's objective is to create a decision help for owners of residential buildings for several families regarding the renewal of decentralized heating and warm water preparation systems in the flats. The focus lies on a comparison of the costs of typical systems on the basis of a full cost calculation. This is done by taking into consideration the intentions of residential building companies like the reduction of additional costs to be paid by the tenants (both for social reasons and to make the flats easier to rent), low investment costs, low maintenance costs, energy saving, tenants' claims for comfort and acceptance by the tenants, economical reasons, especially regarding flats fully amortized (activation in the balance sheet). In addition to the quantitative comparison, the advantages and disadvantages of the different systems were also compared to one another from the qualitative point of view. [German] Ziel des Forschungsvorhabens ist die ...
Zusammenfassung Das Lungenkarzinom ist eine der h?ufigsten Krebserkrankungen und die h?ufigste Krebstodesursache. Mit der Einf?hrung innovativer Substanzen ist die M?glichkeit einer individualisierten Therapie gegeben, die eine Verbesserung von Prognose und Lebensqualit?t verspricht. Die Wirksamkeit dieser Therapeutika basiert auf spezifischen molekularen Eigenschaften des Lungenkarzinoms und stellt neue Anforderungen an die pathohistologische Diagnostik. Neben dem Histotyp haben sich molekulare Alterationen, insbesondere EGFR-Mutationen, als pr?diktive Marker erwiesen. Die histologische Typisierung umfasst daher nicht nur die Unterscheidung von SCLC und NSCLC, sondern die Subtypisierung der NSCLC unter Einbezug immunhistologischer und molekularer Untersuchungen. Zusammenfassend werden Kri...
Apart from condensing the off-air condensers have a number of additional functions, which have been added more or less incidentally as development progressed. Advanced development of certain types of turbine condensers justifies the hope that these additional functions can be improved as power plants become cheaper and simpler.(orig.) [German] Kondensatoren haben neben ihrer Hauptaufgabe, der Kondensation des Turbinenabdampfes eine Reihe zusaetzlicher Funktionen, die sich z.T. im Laufe der Entwicklung eher beilaeufig ergeben haben. Der hohe Entwicklungsstand bei bestimmten Bauarten von Turbinenkondensatoren laesst die Erwartung zu, dass im Zuge der Vereinfachung und Verbilligung von Kraftwerksanlagen 'Nebenfunktionen' verbessert werden koennen. (orig.)
This conference report contains the lectures presented at the BMBF status seminar on the cooperative project ``Bodies of landfills``, which took place at Wuppertal on 25th and 26th April 1995. The cooperative project was started in autumn 1993 and studies the long-term behaviour of wastes deposited at landfills in general. Inorganic and municipal wastes are studied separately. (orig./SR) [Deutsch] Der vorliegende Tagungsband enthaelt die Vortraege des BMBF-Statusseminars zum Verbundvorhaben `Deponiekoerper` vom 25. und 26. April 1995 in Wuppertal. Das Verbundvorhaben `Deponiekoerper` wurde im Herbst 1993 begonnen und befasst sich ganz generell mit dem langfristigen Deponieverhalten von Abfaellen. Es ist unterteilt in die Untersuchung von anorganischen Abfaellen und von Siedlungsabfaellen. (orig./SR)
The following subjects were discussed at the conference: Stability of welded joints, creep stress in CrMo steels, life prediction, developments in modern power plant steels, testing, calculation of deformation, crack propagation and crack analysis under complex loads. [German] Die Autoren der Tagung referieren ueber folgende Themen: Stabilitaet von Schweissverbindungen, Kriechbeanspruchung von Chrom-Molybdaen Staehlen, Lebensdauervorhersage, Entwicklungen fuer die Anwendung in modernen Kraftwerken, Prueftechnik, Berechnung von Verformung, Rissentwicklung und -bewertung bei komplexer Beanspruchung. (uke)
The project is intended to yield information on the transfer factors describing the transfer of ingested radionuclides to breast milk for the following elements: antimony, cerium, chromium, cobalt, gallium, lanthanum, molybdenum, niobium, radium, ruthenium, silver, thorium, titanium, and uranium. Those yet unknown or poorly known transfer factors are required in order to be able to develop a reliable model for description and assessment of the transfer of the radionuclides and the possibly resulting hazardous doses to infants, and for subsequent formulation of recommendations for radiological protection of the population. (orig./CB) [German] Ziel des Projektes ist die Ermittlung von Transferfaktoren fuer den Uebergang von Radionukliden aus der Nahrung der Muetter in die Muttermilch fuer die Elemente Antimon, Cer, Chrom, Cobalt, Gallium, Lanthan, Molybdaen, Niob, Radium, Ruthenium, Silber, Thorium, Titan und Uran. Um die Exposition und damit die ...
The danger potential for 110 kV cables, which are installed on racks and in tunnels, caused by catching fire because of arcing short circuits and mechanical overstressing by peak shortcircuit current, has been experimental analysed under Bewag network conditions. As a result, recommendations for an improved installation of 110 kV cables are given. (orig.) [Deutsch] Fuer offen gelegte 110-kV-Kabel in Raeumen, auf Fussboeden und in Schaechten wurde das von Kurzschluessen auf den Kabeln ausgehende Gefaehrdungspotential fuer die Entstehung von Kabelbraenden durch Fehlerlichtboegen und fuer eine mechanische Ueberbeanspruchung von Kabeln durch Stosskurzschlussstroeme unter Beruecksichtigung der Netzverhaeltnisse der Bewag experimentell untersucht. Im Ergebnis geben die Verfasser Empfehlungen fuer die sichere Anordnung offen gelegter 110-kV-Kabel. (orig.)
The article presents measures for the solution of construction-biological problems and for reducing the pollutant load of buildings. (HW) [Deutsch] Der Artikel berichtet ueber Massnahmen ueber Sanierung von baubiologischen Schwachstellen und Schadstoffbelastungen in Gebaeuden. (HW)
Within the context of practice-oriented constraints the speed and output power control of power plant turbines represents a big challenge for engineers for designing low order controllers with only a few parameter settings and in order to meet the requirements of the Deutsche Verbundgesellschaft. The results of a detailed study of the current standard and an improvement of the speed dynamic for load rejections are shown. (orig.) [German] Die Regelung der Drehzahl und die Leistung von Kraftwerksturbinen stellt im Rahmen von praxisorientierten Nebenbedingungen, wie z.B. dem Einsatz von Reglern geringer Ordnung mit wenigen Einstellparametern und den Vorgaben der Deutschen Verbundgesellschaft, eine grosse Herausforderung fuer den Entwicklungsingenieur dar. Die Ergebnisse einer ausfuehrlichen Untersuchung des bisherigen Standards und einer Verbesserung der Drehzahldynamik bei sogenannten Abfangpruefungen werden vorgestellt. ...
The picture of wind energy parks at the German North Sea Coast is well-known. There are also some of them on the Northern Friesian Islands. Recently, however, biogas plants have been conquering the western coast of Schleswig-Holstein, starting from the continent.
The applicability of isothermal solidification as a contacting method for solar cells was proved for the systems AgSn and AuIn. The process is advantageous in that it requires no fluxes, no inert gases, and no pretreatment of the components. The IE contac...
The authors shortly describe some basic aspects relating to probabilistic reliability calculation and to the derivation of component reliability data. (GL)
The report deals with the energy consumption of traffic and its emissions of hazardous substances into the air, and stresses the advantages of the electric car with respect to energy consumption and noise generation. 5 figs., 3 refs.
Line conditioners control voltage isolated in external conductors. Changes of Stern-Delta connections involve voltage drop in a nonloaded external conductor and are therefore compensated. The payback period of a line conditioner lasts normally between one to three years, according to the investment cost for the alternative medium-sized voltage to be constructed. (GL)
Abstract Der folgende Artikel setzt die Reihe unserer ChiuZ-Beitrge zur Chemi- und Biolumineszenz mit einer interessanten und neuen experimentellen Arbeit zum -kalten Licht- spezieller ungesttigter Verbindungen fort, deren Anwendung auch in der modernen Zeit der Nanotechnologie im biochemischen bzw. medizinisch-chemischen Labor vllig neue Akzente gesetzt hat.
A knowledge based system for pitting corrosion is presented. It can be used for material selection for specific pitting corrosion conditions or to check the suitability of a chosen material. The user can enter his own knowledge. The expert system is an integration of traditional expert system technology and neural networks. (orig.)
The amended Radiation Protection Ordinance of 2001 contains regulations on natural radioactive materials, whose recycling or disposal poses practical problems. There is little experience in this field so far. [German] Die novellierte Strahlenschutzverordnung von 2001 befasst sich auch mit natuerlich vorkommenden radioaktiven Stoffen. Bei ihrer Verwertung oder Beseitigung ergeben sich praktische Fragen, die beachtet werden muessen. Erfahrungen auf diesem Gebiet liegen bisher kaum vor. (orig.)
It is reported about the adsorptive stripping voltammetric determination of uranium, antimony, tin, vanadium and molybdenum using chloranilic acid as complex forming reagent. The determination limits are in the l{sup 1}-range. (orig.) [Deutsch] Es wird ueber die Bestimmung von Uran, Antimon, Zinn, Vanadium und Molybdaen durch Adsorptions-Stripping-Voltammetrie mit Chloranilsaeure als Komplexbildner berichtet. Die Bestimmungsgrenzen liegen im ng l{sup -1} Bereich. (orig.)
In this project the influence of residual compression stresses on the stress corrosion cracking behaviour of the turbine disc steel 26 NiCrMoV 14 5 (Rp(sub 0.2) = 850 N/mm(sup 2)) was investigated. The residual compression stresses were produced by shot p...
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 ...
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 ...
Numerous task forces at universities, other research institutions and in industry have been concerned with the development of methods fit to replace animal experiments. A great many useful in-vitro test systems were developed. From 1986 to 1993 the ``In-vitro Systems`` newsletter was published with the support of the federal ministry of science and technology. Its purpose was to intensely promote the concept of in-vitro systems for the benefit of experimental animals among scientists, and to demonstrate to the public the limits of such endeavours. This brochure is a compilation of 141 contributions from all annual volumes, dealing inter alia with research projects for the development of pharmaceuticals, toxicology and quality control, ethic-philosophical considerations, meeting reports, and book reviews. Changes or revisions have not been made; so some of the contributions have been overtaken by more recent developments. (MG) [Deutsch] Viele Arbeitsgruppen an Universitaeten, anderen ...
CNG vehicles suffer from an uncontrolled temperature rise of the gas inside the tank during the filling process and heat exchange with the environment leads to variable filling levels. A partly filled tank reduces the range of CNG vehicles and works as a impediment to the spreading of environmentaly more friendly CNG vehicles. The increase of the pressure inside the tank combined with a prolongation of the filling time beyond three minutes can reduce the deficit of the filling process. For economic reasons the time required for refuelling should be as short as possible without the need to operate the filling station with a critical pressure. To meet this target the current technique requires further improvement. (orig.) [Deutsch] Die betriebliche Praxis bei Tankvorgaengen von Erdgasfahrzeugen zeigt, dass waehrend des Tankvorganges die Temperatur des getankten Erdgases im Fahrzeugtank ansteigt. Waehrend und nach Beendigung des Tankvorganges findet ein ...
Two spreading experiments were performed at the FARO facility with prototypical core melts of a UO{sub 2}/ZrO{sub 2} weight percentage of 80/20. The objective was to obtain data on the spreading at flow rates of about 2 l/s of more than 100 kg prototypic high temperature oxide melt on a dry and wet stainless steel plate. For the second spreading test a shallow water layer of 10 mm was added on the substrate. Solutions for an isothermal spreading with a constant volume flux boundary condition in a sector with an angle {phi} are used to analyse the FARO L-32S experiment and to identify the source of discrepancies between the code results (THEMA, CORFLOW) and the experimental findings. The observed spreading behaviour of both FARO experiments can only be explained if an initial melt temperature below the liquidus temperature, i.e. about 120 K lower than the temperature measured by the UTS sensors is assumed. (orig.) [German] Zwei Ausbreitungsexperimente mit einer UO{sub 2}/ZrO{sub 2} ...
On behalf of the United Nations Environment Programme (UNEP) a study has been established by the Refrigeration, Air Conditioning and Heat Pump Technical Options Committee in which famous experts of refrigeration technology compiled facts which allow for a reliable prospect of real possibilities of changing from fluorine hydrogen to ozone innoxious substitutes and substitute technologies. With regard to the organization, a division into 6 committees for the establishment of the study has been made: 1. Refrigeration Options Committee, 2. Foams Options Committee, 3. Solvents, Coatings and Adhesives Options Committee, 4. Aerosols, Sterilants and Miscellaneous Uses Options Committee, 5. Halons Technical Options Committee and 6. Economic Options Committee. (BWI).
There is much interest worldwide in low-emission, low-noise electric cars. Modern vehicles with advanced technology are an interesting alternative to conventional cars. (orig.) [Deutsch] Das Interesse an den emissionsfreien und leisen Elektroautos ist weltweit ungebrochen. Die heute verfuegbaren Fahrzeuge zeigen die betraechtlichen, in den letzten Jahren erzielten Fortschritte, die sie fuer immer mehr Anwender zu einer beliebten Alternative zur Benutzung des konventionellen Autos machen. (orig.)
A manipulator for checking the inside of a vertical, flange-shaped collector of a horizontal steam generator consists of a rotating mast with bearings at the top and bottom ends with a support that can be moved along the length of the mast for the checking system mountings. The support is propelled by a drive spindle placed parallel to the mast with its drive head bearing in the support and locked into a toothed rack attached to the mast. The checking system mountings are fitted in or on the walls of the support and are very close to the box-shaped support. Their retractable arms are hinged.
Progress reports on the European Research Centre for Air Pollution Control Measures project are presented. Topics covered were: assessment and analysis of the impacts of airborne pollutants on forest trees, and distinction from other potential causes of recent forest dieback; research into atmospheric dispersion, conversion and deposition of airborne pollutants; development and optimization of industrial technical processes to reduce or avoid emissions; and providing instruments and making recommendations to the industrial and political sectors.
In the well-known devices for increasing the decontamination factor in the treatment of radioactive waste water by evaporation, which consist of narrowing devices with evaporator sump and condenser, droplets of liquid and solid particles are carried over from the breeder space, which are radioactive and therefore make the decontamination factor worse. Better results are obtained if one places a fibre bed filter between the evaporator sump and the condenser, preferably in a horizontal connecting pipe between the evaporator sump and the condenser.
In the presented case study CRS processing was able to improve the overall data quality of the processed lines in terms of signal-to-noise ratio and imaging. The complex geology is causing serious problems in conventional NMO/DMO processing that were solved by CRS processing. Even a depth processing with velocities calculated from CRS attributes gives good results similar to those from PreSDM in terms of the velocity field. Data quality of poststack depth migrated CRS stacks is even better than the image from PreSDM. (orig.)
The paper examines the influence of various total strain amplitudes and mean strains on the cyclic deformation processes in GGG-60 at temperatures of 20 C, 350 C, and 500 C ,the total strain amplitudes being varied between 1.0 permille {<=}{epsilon}{sub a,t}{<=}3.8 permille , and the mean strains between -4.0 permille {<=}{epsilon}{sub m,t}{<=}4.0 permille . - [Deutsch] In der Arbeit wird der Einfluss unterschiedlicher Totaldehnungsamplituden und Mitteldehnungen auf das Wechselverformungsverhalten von GGG-60 bei Temperaturen von 20 C, 350 C und 500 C untersucht. Dabei werden die Totaldehnungsamplituden zwischen 1,0 permille {<=} {epsilon}{sub a,t} {<=} 3,8 permille und die Mitteldehnungen zwischen -4,0 permille {<=} {epsilon}{sub m,t} {<=} 4,0 permille variiert. (orig./MM)
Burner nozzles were often redesigned in order to improve flow design and manufacturing quality. Maintenance intervals, however, are not satisfactory for the operators of such plants. There is no definitive answer as to whether upgraded design allows to lengthen these intervals or whether additional measures are required. Gas turbines may break down for a large number of reasons. This article shows that many of the causes of operational failure and damage are preventable. Damage management will be successful if manufacturers, operators and independent institutions work together.(orig.) [German] Es wurden in der Vergangenheit mehrfach Veraenderungen an den Brennerduesen vorgenommen. Dabei wurden Verbesserungen in der stroemungstechnischen Auslegung und der Fertigungsqualitaet erzielt. Die derzeit noch gueltigen Wartungsintervalle sind fuer den Betreiber unbefriedigend. Inwieweit diese Intervalle mit der modifizierten Ausruestung verlaengert werden koennen oder ob weitere Massnahmen ...
By joining the `climate association of European cities`, Frankfurt has agreed to reduce its CO{sub 2}-emissions by 50% by the year 2010. The so-called `climate offense 1991` was the first regulatory paper to be set up by a community to reach this goal over a long term. This report now represents the present level of the project. Main points are the development of houses with low entropy, the retrofitting of heating systems, water saving measures and energy management. (BWI) [Deutsch] Durch den Beitritt zum `Klima-Buendnis der Europaeischen Staedte` hat sich die Stadt Frankfurt/M. verpflichtet, die CO{sub 2}-Emissionen bis zum Jahr 2010 um 50% zu senken. Mit der sog. `Klimaoffensive 1991` wurde dann erstmals von einer Kommune in Deutschland ein detailliertes Regelwerk aufgestellt, um dieses Ziel langfristig erreichen zu koennen. Der vorliegende Bericht stellt den aktuellen Stand des Projektes dar. Kernpunkte sind die Entwicklung von ...
In the last few years the supercharging of Otto-cycle-engines has regained popularity, as demonstrated by a number of series-production engines. After listing the aims to be met by a modern supercharger the paper describes the technical status of mass-produced or close to production superchargers. This is followed by a comparative evaluation of the systems, enabling the reader to select possible solutions for a projected supercharger-engine-system by means of a comparison chart. The paper is concluded by a list of possible directions for further development and additional potential for twin-screw superchargers. (orig.) [German] In neuerer Zeit hat die Aufladung von Ottomotoren wieder ein verstaerktes Interesse gefunden, das sich auch in einer Anzahl serienmaessig gefertigter aufgeladener Motortypen wiederspiegelt. Der vorliegende Beitrag beschreibt, nach einer Darstellung der Anforderungen an ein modernes Aufladegeraet, den Stand der Technik bei serienmaessigen ...
Two of the working sessions of the meeting were devoted to aspects of international atomic energy law; the international character of the meeting was also reflected by the home countries of the members of the panel discussion concluding the working sessions. There was substantial reason to put emphasis on the international dimension of the topics discussed. In June 1994, the Nuclear Safety Convention had been signed in Vienna by diplomatic representatives of the signatory countries, and this Convention marks a signpost in the history of international atomic energy law. At the time the meeting was held, negotiations for improving the international nuclear lability law, which had been dragging on since 1989, had come to a stalemate. The meeting offered a suitable forum for taking a scientific approach to tackle the complex problems involved in reshaping the law on nuclear safety and nuclear liability. The third working session of the meeting has been discussing topics relating to the ...
In addition to dependable starting - even at extreme sub-zero temperatures - the starting behaviour of modern commercial vehicle diesel engines is increasingly being evaluated on the basis of HC emissions in the starting and warm-up phases. To improve their performance in this respect, most small and medium-sized diesel engines (with a capacity of 3 to 12 litres) are therefore equipped with intake air heating systems. As an alternative to high-performance, fuel-burning flame start systems, the automotive industry supplier Beru has now developed a new type of self-regulating electric heating element which not only ensures dependable starting with short heating times but also allows drastic reductions in HC emissions. (orig.) [Deutsch] Das Startverhalten moderner Nutzfahrzeug-Dieselmotoren wird, ergaenzend zum Hauptmerkmal des sicheren Starts auch bei extremen Minustemperaturen, zunehmend anhand der HC-Emission in der Start- und Warmlaufphase beurteilt. Zur ...
Particulate Reinforced Titanium matrix composites (PRTi) exhibit some improved specific mechanical properties in comparison with those of unreinforced titanium alloys as a result of the combination of the high strength and stiffness of ceramic particles with the toughness and damage tolerance provided by the metal matrix. The poor tribological properties of the titanium exclude titanium alloys from applications where wear resistance is required (brakes, rotating parts, sliding parts). The addition of ceramic particles improves the tribological properties of metals sensitive to adhesive and /or abrasive wear significantly. In this work, the wear resistance and the friction coefficient of Ti6Al-6V-2Sn reinforced with TiC particles and Ti6Al-4V reinforced with SiC particles (prototype material) are compared with the unreinforced alloys. Pin on disc and pin on ring tests were carried out against standard steel (100Cr6) as a function of pressure, speed and temperature. The results show ...
Shell Solar GmbH is working on a variant of the so-called stacked elemental layer process for CIGSSe absorber production. The metal films resp. the selenium are deposited on the Mb electrode at room temperature by DC sputtering (CIG) or evaporation (Se) and then processed into semiconductors by rapid thermal annealing (RTP). Currently, the mean efficiency of the pilot plant is i 12.6 {+-} 0.2 % for non-sealed 30 x 30 cm{sup 2} modules, the key efficiency is 13.0 %. In addition to the 30 x 30 cm{sup 2} pilot line, a small series of 60x90cm2 modules was constructed in December 2004. Here, the mean efficiency was 13.0 percent while the average module power was higher than 60 W. The contribution also describes investigations of ceramically sputtered n-ZnO:Al layers with reduced Al concedntrations of 1 percent and on reactively sputtered n-ZnO.Al layers from the double roller magnetron. (orig.) [German] Bei Shell Solar GmbH wird eine Variante des sogenannten ...
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.) ...
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 ...
The methods introduced for the field of cleaning waste water can be classified under various processes. Chemical oxidation is done with ozone, hydrogen peroxide and ultraviolet irradiation with subsequent biological decomposition. Another method is ultra-filtration with recovery of valuable materials or waste water ponds with algae biomass to decompose ammonium compounds, nitrates and phosphates. (EF) [Deutsch] Die auf dem Gebiet der Abwasserreinigung vorgestellten Methoden kann man in verschiedene Verfahren einordnen. Die chemische Oxidation erfolgt mit Ozon, Wasserstoff-Peroxid, UV Bestrahlung und anschliessenden biologischen Abbau. Eine andere Methode ist die Ultrafiltration mit Rueckgewinnung von Wertstoffen oder Abwasserteiche mit Algenbiomasse zum Abbau von Ammoniumverbindungen, Nitraten und Phosphaten. (EF)
Many power plants use treated surface water as boiler feedwater and have difficulties in keeping within the limits for organic substances in feedwater (TOC < 200 ppb) or acid conductivity in steam condensate (< 0.2 {mu}S/cm). The characteristics of surface water and the role of organic substances in boiler feedwater are explained and discussed. [German] Viele Kraftwerke bereiten fuer die Erzeugung von Kesselspeisewasser Oberflaechenwasser auf und haben Probleme, die Richtlinien fuer organische Stoffe im Speisewasser (TOC < 200 ppb) oder Saeure-Leitfaehigkeit in Dampfkondensaten (< 0,2 {mu}S/cm) einzuhalten. Die besonderen Eigenschaften von Oberflaechenwaessern und die Bedeutung organischer Stoffe in Kesselspeisewasser werden erlaeutert und diskutiert. (orig.)
Zusammenfassung Hintergrund Endograftimplantationen im oder am Aortenbogen stellen besondere Herausforderungen an die Implantationstechnik und an die mechanischen Eigenschaften von Stentgrafts und ihren Einf?hrungssystemen, bedingt durch die Notwendigkeit, die Prothesen punktgenau abzusetzen und durch die mit der Biegung im Aortenbogen zunehmende Reibungswiderst?nde innerhalb der Einf?hrungssysteme. Die Endograftsysteme der 1. Generation (Talent?, Zenith TX 1?, TAG?) zeigten in dieser Lokalisation technisch bedingte Limitationen. Neue Prothesen Bei den seit 2004 und 2005 verf?gbaren neuen Stentgrafts (E-vita?, Zenith TX 2?, Valiant?, Relay?) sind diese Limitationen weitgehend ?berwunden. Durch technische Verbesserungen von Stentgrafts und Einf?hrungssystemen ist es nun m?glich, auch lange ...
Backgrund: Interleukin-1, tumornecrosisfactor-{alpha} and interferon-{gamma} endogenously provide protection of the hematopoietic system against radiation. Thiols have already been used successfully as radioprotective agents. In this study the effect von N-acetylcysteine (NAC) on the release of interleukin-1{alpha} and {beta} (IL-1), interleukin-2 (IL-2), interferon-{gamma} (IFN-{gamma}) and tumornecrosisfactor-{alpha} (TNF-{alpha}) was assessed in an in vitro assay. Patients and Methods: Whole blood samples from 8 healthy volunteers were stimulated with 7.5 {mu}m/ml PHA. NAC was added at concentrations of 0.6, 6, 12 and 24 mmol/l. Subsequently the samples were irradiated with a dose of 18 Gy according to preceding validation experiments. Results: IL-1{alpha}, IL-1{beta} and IL-2: In comparison to simulation and radiation alone the addition of 0.6 and 6 mmol/l with IL-2 also 12 mmol/l, NAC resulted in a significant increase of the cytokine-concentrations. The ...
Coordination chemistry on transition metal chalcogenides offer better conditions for multielectron charge transfer processes on solid/electrolyte interfaces. In this contribution, materials whose band energies are derived from d-states of the transition metal will be shown. Problems related to the reactivity, stability and photoactivity toward the generation and conversion of fuels will also be discussed. (orig.) [Deutsch] Die an halbleitenden Uebergangsmetall-Elektroden beobachtete Koordinationschemie bietet guenstige Voraussetzungen fuer den Mehrelektronen-Transfer an der Festkoerper/Elektrolyt Grenzflaeche. Beispielhaft werden in diesem Beitrag Elektrodenmaterialien vorgestellt, deren Energiebaender sich von d-Zustaenden der Uebergangsmetalle herleiten. Diskutiert werden Probleme der Reaktivitaet, der Stabilitaet und der Photoaktivitaet im Hinblick auf die Erzeugung und Umsetzung von Brennstoffen. (orig.)
The energy cost of compressors accounts for up to 90% of the total cost. Oil-free compressors could reduce the cost almost by half, i.e. annual savings of 112,500 DM would be achievable. [German] Ueber die Gesamtlaufzeit betrachtet, machen die Energiekosten bei Verdichtern bis zu 90% der Gesamtkosten aus. Deshalb muss bei der Auswahl von Kompressoren dem Energieverbrauch besondere Aufmerksamkeit geschenkt werden. Mit oelfreien Kolbenkompressoren liessen sich in einem speziellen Fall die Kosten fast halbieren, was jaehrlichen Einsparungen von 112 500 DM entspricht. (orig.)
The low-cycle fatigue behaviour of copper and a-brass CuZn30 was investigated in uniaxial and biaxial tests. Planar biaxial fatigue tests were carried out using cruciform samples with proportional stain paths with and without phase shift between the two axes. Microcharacterisation was performed by electron microscopy as well as by high-resolution X-ray line profile analysis. The biaxial cyclic stress-strain curves show good agreement with the uniaxial ones using the von Mises equivalent strain hypothesis. The dislocation densities and microhardness values of the biaxial case, however, show significantly lower values compared to the uniaxial case at equivalent von Mises stresses.
Zusammenfassung Die Festigkeitshypothesen und Flie?fl?chen aus den klassischen Kursen der Mechanik (die Normalspannungshypothese, die Modelle nach von Mises und Tresca) reichen oft nicht aus, das tats?chliche Verhalten von Bauteilen unter Belastung zu erfassen. Deshalb werden in der Literatur weitere Modelle mit einem oder mehreren Parametern vorgeschlagen. Diese Modelle beschr?nken allerdings die Geometrien der zul?ssigen Formen der Fl?chen im Spannungsraum. In dieser Arbeit wird ein auf die Zugspannung normiertes Druck-Torsion-Diagramm vorgestellt, in dem sich die Modelle inkompressiblen Materialverhaltens miteinander vergleichen lassen. Mit diesem Diagramm wird der Begriff der Symmetrie der Fl?che in der ?-Ebene verdeutlicht. Die konvexen Fl?chen inkompressiblen Materialverhaltens sind ...
Diagnostic systems make it possible to recognize incipient faults in good time and help to increase the availability of power stations. The thermal efficiency and the effective terminal output are didicated by a number of influences. Deviations from the expected status can be identified via continuous recording of the operating parameters and calculation of derived data. An improved efficiency and economical load distribution lead to considerable cost savings. (orig.) [Deutsch] Die Verarbeitung von Messwerten und Signalen ermoeglicht eine umfassende Beurteilung des Anlagenzustandes und die Erkennung sich anbahnender Veraenderungen. Stoerungen, Schaeden oder eine unwirtschaftliche Betriebsweise koennen fruehzeitig erkannt werden. Erhoehte Verfuegbarkeit, geringerer Brennstoffverbrauch und optimierte Lastaufteilung bringen Kostenvorteile. (orig.)
The article describes the solar aircraft `Icare`` which was constucted in a joint project by engineers and scientists of Stuttgart university. The aircraft requires slightly more than one kW for staying up. The theoretical fundamentals are presented in the dissertation of Peer Frank, ``Aircraft design for minimum fuel consumption` (Institute of Aircraft Engineering, Stuttgart, 1992). (orig.) [Deutsch] Allein mit Sonnenkraft kann das Flugzeug `Icare` fliegen. Es entstand in Gemeinschaftsarbeit von Ingenieuren und Wissenschaftlern der Stuttgarter Universitaet. Das Solarflugzeug Icare benoetigt etwas ueber ein Kilowatt, um oben zu bleiben. In seiner Doktorarbeit `Die Auslegung von Flugzeugen mit geringstem Antriebsleistungsbedarf` (Institut fuer Flugzeugbau, Stuttgart, 1992) hat der Duesseldorfer Peer Frank die theoretischen Grundlagen dazu behandelt. (orig.)
All patients with von Willebrand?s disease (vWD) who showed an arterial or venous thrombosis and were reported in the literature have been evaluated. 11 patients had arterial thrombosis while 19 had venous thrombosis for a total of 30 cases. 9 out the 11 cases with arterial thrombosis had myocardial infarction. Two had cerebral thrombosis. Associated risk factors for arterial thrombosis were available only for three patients who showed, respectively, smoking and dyslipidemia (2 cases) and smoking and intravenous desmopressin infusion (1 case). The majority of patients with venous thrombosis showed DVT with or without PE. Four patients presented with apparently isolated PE. In two instances thrombosis occurred in unusual sites (central retinal vein and portal vein, respectively). Several as...
Knowledge, assessment and understanding of phenomena caused by ageing, together with systematic utilization and extension of the technical life-time of components and systems, are of critical importance to the safety and economy of electricity generation in nuclear power stations. Economic use can be optimized by integrated ageing and life-time management; it can also be used to improve performance characteristics. (orig.) [Deutsch] Fuer die Sicherheit und Wirtschaftlichkeit der Stromerzeugung in Kernkraftwerken sind die Kenntnis, Bewertung und Beherrschung alterungsbedingter Phaenomene und systematische Ausnutzung bzw. Verlaengerung der technischen Lebensdauer der Komponenten und Systeme von zentraler Bedeutung. Durch ganzheitliches Alterungs- und Lebensdauermanagement, das auch auf die Verbesserung von Leistungsmerkmalen abzielt, kann der wirtschaftliche Nutzen optimiert werden. (orig.)
Wood is currently having a renaissance as a domestic fuel. Wood pellets, usually about 8 mm in diameter and 40 mm long and produced from sawmill and wood processing residues by pressing without binders, are gaining general acceptance. According to a market analysis of Solar Promotion GmbH, Pforzheim, about 4,800 pellet-fuelled heating systems with automatic fuel supply and with a total thermal capacity of 35 kW are in operation in Germany, and 2000 new ones were installed in 2000. [German] Holz als Brennstoff erlebt in vielen Heizkellern und Kaminen eine Renaissance. Und zwar nicht in Form von Holzscheiten, sondern als kleine Presslinge, meist mit einem Durchmesser von acht und einer Laenge von bis zu 40 Millimetern. Als Abfallprodukt von Saegewerken und Holz verarbeitenden Betrieben werden die so genannten Pellets unter hohem Druck und ohne Bindemittel wie beispielsweise Leim hergestellt. Und dieser ...
This article describes the utilization of plastic wastes in a blast furnace. The plastic waste is a substitution for petroleum and coal as a raw material for synthesis gas production. The synthesis gas is the reducing agent in the blast furnace for the reduction of iron ores. You can find here an ecological and economical analysis of this process in comparison to the utilization of petroleum and coal. (SR)
Based on the first part of this report the molybdenum loadings of the red mud were varied and the activity of the catalytic additives was tested in a batch autoclave with TJP VR. The 30% Molybdenum loading (sample Nr. 6) was found to be optimum. Further testing with two vacuum residues (TJP VR and ARH VR) and sample Nr. 6, indicates the influences of the process parameters for hydrogen pressures of 9-15 MPa, temperatures of 440-475 C and residence times of 0-60 min. Obviously 440 C, 12 MPa and a residence time of 30 min are best conditions for hydrocracking of both vacuum residues with sample Nr. 6. (orig.) [Deutsch] Beruhend auf dem ersten Teil des Berichtes wird der Belegungsgrad der Rotmasse mit Molybdaen variiert und die resultierenden katalytischen Zusaetze werden in einem Autoklaven mit TJR VR getestet. Ein Belegungsgrad mit 30% Molybdaen (Probe 6) scheint optimal zu sein. Mit diesem Zusatz werden die Einfluesse der Prozessparameter bei Wasserstoffkaltdruecken zwischen 9 und 15 ...
As waste disposal methods and long-term precautionary care of the environment are closely related, disposal of non-avoidable and intractable residual products is to be viewed primarily from a safety angle. Also, thermal processes airm mainly at treatment, not utilization. 'Safety' in this context addresses both the environmental compatibility of the products and the process itself. In other words, only mature techniques (i.e., safe, proven ones) are employed. (orig.)
In this work, the thermodynamic behaviour of single-stage horizontal spray coolers with one or more spray levels is experimentally examined. Further, a spray cooler calculation model was developed, in order to describe the processes and to make a comparison of the results of calculation and measurement. The state of the mine climate and the cold water are taken as the thermodynamic reference. (orig.).
By the year 2000, the Postal Service aims to reduce its diesel transport by around 15000 vehicles. The advisory service, Detecon, is reviewing alternatives for postal deliveries as part of the ''Post 2000'' initiative. One such system is an electric-powered vehicle with a zinc-air battery from the Israeli firm Electric Fluid Limited (EFL). (orig.)
Smart electricity and gas supply grids are a prerequiste for full-scale utilization of the potential of modern energy-saving appliances and equipment. Direct exchange of information between the supplier and the consumer is indispensable for reducing costly and energy-intensive peak loads. (orig.)
Summary.? Measuring von Willebrand factor (VWF) activity is essential to the diagnosis of von Willebrand disease (VWD). The VWF activity is usually assessed based on measurement of the ristocetin cofactor (VWF:RCo). However, that test is technically challenging and has high intra- and inter-assay variabilities. The HemosIL VWF activity (VWF:AC) is a fully automated assay, recently proposed as a good alternative to VWF:RCo for VWD diagnosis. This study was undertaken to assess this new method. First, the analytical performance of VWF:AC on an automated coagulo-meter (ACLTop) was determined, and then this new method was compared with VWF:RCo and the platelet function analyzer (PFA100) for 160 patients referred for VWD screening. The VWF:AC achieved acceptable precision with within-run and between-run coefficients of variation ranging from 2.3% to 14.1%, and linearity from 10% to 100%. Despite some marked differences between VWF:AC and VWF:RCo for ...
It may be necessary to reduce microbiological contamination of crude drugs (medicinal plants or their parts like roots, leaves, flowers). This can be done by treating the drugs with ionizing radiation. Meethods for detection of such an irradiation were developed. It could be pointed out that measurements of luminescence, viscosity and electron spin resonance were suitable for specific drugs, but not for all drugs. (orig.).
Biological cells of the nitrogen fixating bacteria Xanthobacter autotrophicus GZ 29 have been cultivated with 57-Fe, and from the nitrogenase of these cells the 57-Fe marked molybdenum-iron-protein is extracted. The Moessbauer spectra of this enzyme show that the structure of the iron cluster is similar to the structure in the molybdenum-iron-proteins of Azotobacter vinelandii, Klebsiella pneumoniae or Clostridium pasteurianum.
In this paper, we derive the moderate deviation principle for stationary sequences of bounded random variables with values in a Hilbert space. The conditions obtained are expressed in terms of martingale-type conditions. The main tools are martingale approximations and a new Hoeffding inequality for non adpated sequences of Hilbert-valued random variables. Applications to Cramer-Von Mises statistics, functions of linear processes and stable Markov chains are given.
A numeric method for predicting mineral ash deposition in coal dust furnaces is presented which is based on a bidirectional working time coupling of thermodynamic calculation routines (ChemApp{sup TM}) with the commercial CFD code FLUENT{sup TM}. The deposition characteristics of particles and wall surfaces is assessed on the basis of evaluations of flow simulation parameters and results of thermodynamic calculations for the mineral matter contained in the fuel particles, taking into account the complete energy, momentum and mass exchange history of the ash and the mineral conversion. The models enables calculations of the gaseous release of mineral components (e.g. alkaline substances and chlorine) from ash during combustion and its distribution inside a combustion chamber. The method and model are validated using experimental data. (orig.) [German] In der vorliegenden Arbeit wird ein numerisches Verfahren beschrieben, mit dem die Ansatzbildung in Kohlestaubfeuerungen praediktiv ...
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 ...
The system study 'High Temperature Superconductivity (HTS) in power systems' lists the technical and economical advantages for power generation, transmission and distribution systems using components made of HTS material as seen in the light of current knowledge in the superconductivity area. This report lists the advantages of using high-temperature superconductivity in the power industry area and summarises the results obtained in various case studies on the subject.
Due to the fast cooling of steam turbines, the shutdown time during maintenance or when repairing faults and damage can be shortened. This booklet describes various processes for cooling steam turbines. It is recommended that fast cooling should be planned in designing new plants and corresponding arrangements should be provided in the form of pipe connections and valves. (DG).
The vibration behavior of turbomachine bladings is described, and the behavior of different kinds of coupled low pressure stages was experimentally investigated. Besides purely stationary flow conditions, conditions were also considered where pulsating fl...
Nondestructive inspection of carbon fibre-reinforced plastics (CRFP) using eddy current methods is based not only on the conductivity of the fibres. High frequencies (up to 10 MHz) give access to capacitive effects reflecting properties of the matrix. The paper presents a method using rotating eddy current probes to measure the anisotropic electrical properties. Potential applications of this method are the structural identification of laminates and the estimating of its degradation. (orig.)
The report investigates a number of joining techniques, i.e. isothermal solidification, ultrasonic welding, thermocompression, and glueing. (HW) [Deutsch] In diesem Vorhaben wurden verschiedene Verbindungstechniken untersucht: Isotherme Erstarrung; Ultraschall-Schweissen; Thermokompression; Leitkleben. (HW)
This compact book of tables attempts to give practicians a survey of the corrosion behaviour of common structural and coating materials. Corrosion resistances are presented for steels, alloys, plastics, elastomers, graphite, glasses, and stoneware in environments of NaOH, HNO{sub 3}, SO{sub 2}, ZnCl{sub 2}, NH{sub 3}, H{sub 2}O{sub 2}, ethyl chloride, sodium acetate, and many others. (MM).
The catalytic properties of molybdena-alumina catalysts reduced in hydrogen were studied in the function of the reduction temperature, i.e. in the function of the extent of reduction. The deuterium exchange reaction of benzene was used as model catalytic reaction. It was concluded that the reaction rate constant and the multiplicity factor decreased with the extent of reduction parallel with the change in the extent of dehydroxylation of the catalysts. (orig.)
The acceptances to be obtained during the first operational run, refer to measures proving the functional integrity of the turbine control system and assuring the compliance with the maximum allowable overspeed in case of lead changes or perturbations. The Guideline concerns essentially speed, power, and pressure controllers coupled to generators. It may be appropriately extended to steam turbines serving other purposes.
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 ...
The first commercial vehicle, built by Gottlieb Daimler in Cannstatt (Germany), head foto, had been the begin of a new transport technology around the world. Benz had been consolidated 1926 with Daimler to the Daimler-Benz AG with a new vehicle programme; all trucks over 5 t payload would be powered since 1935 by diesel engines only. Worldwide all-wheel drived vehicles had been under development for different purposes. After 1945 the European Automobil industry launched at first former types followed by new designed and improved types. The eight-wheeler used since the twentees in England conquered Switzerland, and in 1984 Germany too. The development of gear boxes and drive axles had been influenced on the drive train demands depending of the engine output and speed and the increased GTW. The future of the commercial vehicles will be determined by the European legislation, higher economy and reduced-pollutant Euro II and later Euro III engines, further by the cooperation of the truck ...
3407 events were registrated up to a distance of 300 m during the period from 12.10.1989 to 31.12.1990, of which 385 could be precisely located. Activities were determined in areas surrounding the dam construction traversal drifts and boreholes at the 875 m level, near the large cavern at 975 m depth, in drifts and caverns above the 875 m level and in the vicinity of the rock salt/carnallitite transition zone to the south-east of the 875 m level. Energies and source parameters were calculated by means of spectres. Energy variations range from 10 J to 10{sup -4} J, the source radii from 3.5 m to 0.2 m, the source dislocations from 10{sup -6} m to 10{sup -8} m, and the stress drops from 10{sup 5} Pa to 0.06 10{sup 5} Pa. Magnitude and type of events observed are usual for mines. The microseismic activity provides an insight into the origin as well as changes of stress and rock mechanical material properties. (orig./HP). [Deutsch] Im Zeitraum 12.10.89 - 31.12.90 wurden 3407 Ereignisse bis ...
On account of a raised appearing of plastic waste and shreddered light fraction (SLF) from old car utilization as well as legal handicaps experiments were carried out at the Institute of Ferrous Metallurgy (RWTH Aachen) on a laboratory rig to inject DSD (Duales System Deutschland)-plastic waste and SLF with the destination of a subsequent raw material utilization in the blast furnace and cupola furnace. The experiments on the laboratory rig with DSD plastics could verify that by injection of specific coal/plastic mixtures into the blast furnace the injection rate could be raised by an improvement in the conversion degree and therefore the amount of the inserted reducing agent can be lowered. The injection of SLF without reduction of the inert materials and of the contents on alloying elements and/or tramp elements by extensive preparation has no advantages according to the experiments for the blast furnace process. Pilot experiments on the cupola furnace showed that, assuming a certain ...
The isothermal flow field for the axial cyclone has been experimentally determined. The velocity fields are used for determination particle paths (particle removal and suspended state), and inter alia of heat and mass transfer processes in the axial cyclone combustion chamber. The results are extremely significant as input value approximations for mathematical modelling, since experimentally obtained results are indispensable for complex flows and geometries. (orig.) [Deutsch] Es ist fuer den Axialzyklon experimentell das isotherme Stroemungsfeld ermittelt. Die Geschwindigkeitsfelder dienen zur Ermittlung der Partikelbahnen (Partikelabscheidung, Schwebebedingung), der Waerme- und Stoffuebertragungsprozesse u.a. in der Axialzyklonbrennkammer. Die Ergebnisse sind als Startwertnaeherung bei einer mathematischen Modellierung sehr wichtig, da bei komplexen Stroemungen und Geometrien versuchstechnische Ergebnisse unumgaenglich sind. (orig.)
The economic development of eastern Europe was associated during the last 15 years with the following average annual increases in energy consumption: Approximately 1% in the sectors industry, building and transport, almost 7% in the farming sector, approximately 3% in households, and nearly 4% in the municipal sector. This trend will not continue. As the economic system shifts from centrally planned to free economy and as the previously secluded economy is forced to face world market conditions as well as changed pars of exchange and conditions of payment, it not only experiences a transitory, sharp dip of economic growth in general but, in particular, drastic structural changes. - While there is to be expected, on the whole a slump in national economic growth, in tradiational branches of industry (e.g., metallurgy, the chemicals and textile industry) as well as in farming, such sectors as the service industry and small trade are expanding. (orig./UA).
For the preparation of photonic probes for hadron physics the determination of energy and polarization of the photons is essential. In this dissertation in a first part a possibility of the determination of the degree of polarization by use of the asymmetry observables is presented. In a second part a possibility isd discussed to perform an energy and polarization tagging of nearly real photons in electron scattering under small Q{sup 2}. By this method it should be possible to tag billions of photons per second.
Facility management has long been regarded as a cost reduction measure, but it is also a means of raising the financial worth of a building so that landlords can get higher rents or sell the building at a better price. [German] Lange Zeit wurde Facility Management als eine Massnahme zur Kostensenkung angesehen. Heutzutage zeigt sich immer mehr, dass das Facility Management sehr viel umfassender zu verstehen ist: Der Wert eines Gebaeudes bemisst sich nicht allein an einer niedrigen Kostenquote, sondern er soll umfassend Investoren wie Mietern den hoechst moeglichen Nutzen bringen. Nicht allein der kostenguenstige Betrieb ist entscheidend, sondern der Wert des Gebaeudes muss insgesamt gesteigert werden. (orig.)
Abstract Plant pathogenic bacteria of the genus Xanthomonas cause a variety of diseases in economically important monocotyledonous and dicotyledonous crop plants worldwide. Successful infection and bacterial multiplication in the host tissue often depend on the virulence factors secreted including adhesins, polysaccharides, LPS and degradative enzymes. One of the key pathogenicity factors is the type III secretion system, which injects effector proteins into the host cell cytosol to manipulate plant cellular processes such as basal defense to the benefit of the pathogen. The coordinated expression of bacterial virulence factors is orchestrated by quorum-sensing pathways, multiple two-component systems and transcriptional regulators such as Clp, Zur, FhrR, HrpX and HpaR. Furthermore, virule...
This process for the preparation of nonaqueous dispersions of water-soluble polymerisates concerns compounds obtained by polymerization of water-soluble unsaturated ethylenic monomers in an emulsion of water in oil. The product is then dewatered to a maximum residual water content of 5% by means of microwaves. The process is azeotropic. The polymer has a molecular weight between 100,000 and 50,000,000, preferably between one and 10 million. Before treating with microwaves, the mixture is concentrated by conventional means until it has a polymer concentration between 20 and 65%, preferably between 40 and 60%. The microwaves have a wavelength between 0.1 and 30 cm. These polymer dispersions can be used in drilling fluids and as additives in tertiary oil recovery. 4 claims.
This is a process for manufacturing a semi-rigid, folding solar generator manufactured from several coated solar cells (Cics), which has at least two folding parts connected together so as to turn by hinges, characterized by the following stages of the process: a) On the back of matrix subsections, in order to cover the connector, carbon fibre strips are glued on, which project over the upper or lower edge of each matrix subsection. b) The projecting ends of adjacent carbon fiber strips are connected with two carbon fibre strips. c) At least two matrix subsections are fixed in separately manufactured carbon fiber frames, and d) the carbon fiber frames, together with the matrix subsections are connected via hinges to a solar generator.
The dogmatic and constitutional basis as well as points of definition concerning the Technical Code Clean Air (TA Luft) are explained at first, followed by an assessment of the air pollution concentrations within the overall complex of the air pollution abatement measures, and an analyses of air pollution concentrations as a concretization of the state-of-the-art. In connection with the differentiation of the various applicability levels of TA Luft, the inhouse validy for authorities, the importance for law courts and, finally, the external binding effect for plant operators and possible third parties are discussed. At the center of attention are questions concerning validity claims and validity possibilities. (HSCH).
Better quality of thermal comfort as well as reduced heat energy demand and accordingly CO{sub 2} emission can be achieved by better heating and ventilation strategies in private buildings. The paper deals with a novel model-based measurement and automation system. It describes the implementation of better strategies under given technical circumstances. (orig.) [German] Durch Verbesserung der Heizungs- und Lueftungsstrategien im privaten Lebensbereich kann sowohl Heizenergie eingespart und damit die CO{sub 2}-Emission verringert, als auch die Raumbehaglichkeit verbessert werden. Der Beitrag behandelt ein modellgestuetztes Mess- und Automatisierungssystem, mit dem die Realisierung der verbesserten Strategien unter gegebenen technischen Randbedingungen praktisch erst moeglich wird. (orig.)
The first part of the study goes into the determination of efficient strategies for the reduction of air pollutants. The developed method is not only derived theoretically but is tested with the concrete example of emissions sources of a German state. The second part goes into the question what the government can do in order to attain that air pollution abatement measures recognized as being efficient will be put into practice. As market economy mechanisms have advantages over central state planning in the allocation of economic resources the question arises if not also for environmental protection market economy tools may contribute to an improvement of the efficiency of air pollution abatement. Therefore the suitability of different tools of environmental policy for the realization of efficient air pollution abatement is investigated and evaluated. This is again not done abstractly but with existing emission sources. (orig./HSCH). 32 figs., 12 tabs.
Zusammenfassung Hintergrund Seit 2005 finden schriftliche Anfragen und Vor-Ort-Pr?fungen durch den Medizinischen Dienst der Krankenversicherungen (MDK) statt. Diese spiegeln in ihren Ver?nderungen sowohl die Erfahrung der Kassen mit dem G-DRG-System (G-DRG German Diagnosis Related Groups) als auch der zust?ndigen ?rztlichen Mitarbeiter und des Krankenhauscontrollings wider. Wir wollten aufarbeiten, welche Entwicklung die MDK-Pr?fungen seit 2005 genommen haben. Hierf?r wurden s?mtliche Pr?fberichte seit Einf?hrung der Pr?fungen ausgewertet. Ergebnisse W?hrend anfangs haupts?chlich Fragen zur Kodier- und Dokumentationsqualit?t erfolgten, werden jetzt ?berwiegend Fehlbelegungspr?fungen durchgef?hrt. Zwischenzeitlich wurden konsequent die unterschiedlichen Klinikbereiche gepr?ft. Die Anfragen ...
More than 200 years after the birth of the steam engine, the first thermal engine ever invented, thermal engines such as steam turbines, gas turbines or internal combustion engines are still driving most generators for electric power generation, most machines, and most vehicles, and this will remain so until far into the next century. (orig.) [Deutsch] Mit Waermekraftmaschinen wie Dampfturbinen, Gasturinen und Verbrennungsmotoren werden auch heute - mehr als 200 Jahre nach der technischen Reife der Dampfmaschine (der ersten Waermekraftmaschine) - die meisten Generatoren zur Stromerzeugung, die meisten Arbeitsmaschinen und die meisten Fahrzeuge angetrieben. Und dabei wird es auch bis weit in das 21. Jahrhundert bleiben. (orig.)
In parking areas of large extent, the removal of engine exhaust gases, especially of their CO gas components with ventilation plant is mainly done by transverse ventilation over short paths. By their presence, the ventilation ducts required for this purpose often reduce the value of the parking space by restrictions with a consequent reduction of their acceptance by the users. Longitudinal ventilation without ducts can be a remedy in such cases. Depending on the required room air quality in the zones of highest loading, the volume flows with longitudinal removal are no greater than with conventional transverse ventilation. This article is concerned with the different methods of operation of the two systems. (orig./BWI)
Three different guidelines define the methods to be used for the quantification of exposures due to the incorporation of radionuclides. The adoption of the Euratom-directive into German law requires the adaptation of these guidelines. With this process, the experiences with the practical application of these regulations must be taken into account. (orig.) [Deutsch] Die Ermittlung der Koerperdosis durch inkorporierte Radionuklide ist in drei Richtlinien des Bundesministeriums fuer Umwelt, Naturschutz und Reaktorsicherheit (BMU) geregelt. Die Umsetzung der Euratom-Direktive in deutsches Recht erfordert die Anpassung dieser Richtlinien. Dabei muessen die bisherigen Erfahrungen mit diesen Richtlinien beruecksichtigt werden. (orig.)
This book is mainly a comparison of the cost of pollution with the cost of environmental protection. As to the causes of pollution, a difference is made between pollutants that accumulate and pollutants that do not accumulate. Because of pollutant accumulation it is necessary to carry out both subsequent pollution abatement measures and to take preventive action which helps to avoid pollutant emission. Growth models serve to substantiate why such preventive action is both ecologically and economically useful as a rule. Finally the study makes a comparison between some tools of environmental protection. It stresses in particular that, if a duty on emissions is levied, the polluter has to bear all the cost of the pollution, while at the same time the quality of the environment can be more successfully improved than by emission standards alone.
This comprehensive final report for the Swiss Federal Office of Energy (SFOE) examines ways to optimise energy flows in mains networks that include distributed generation facilities. Increasing use of decentralised generation, its effects on the operation of low-voltage mains and the efficient use of the 400 V mains is discussed. The principles of operation and construction of controlled storage installations are discussed and concrete examples of their use in both grid-connected and island operation are quoted. Alternatives to storage are looked at from both the technical and economic points of view. The storage technologies used such as flywheels, supercaps, redox-flow batteries and lead-acid accumulators are briefly assessed and the results of simulations are discussed.
Two isothermal sections were prepared at 1000 and 1150 C showing the low-Zr phases of the system Fe-Al-Zr. The phase equilibria were determined by means of X-ray powder diffractometry and electron beam microanalysis. For initial characterisation of mechanical properties, hardness values are determined and added to the tabulated data. (orig./MM) [German] Es werden am Fe-Al-Zr-System zwei isotherme Schnitte durch den zirkoniumarmen Teil des Systems bei 1000 und 1150 C erstellt. Die auftretenden Phasengleichgewichte werden mit Hilfe der Roentgenpulverdiffraktometrie und Elektronenstrahlmikroanalyse aufgeklaert. Zusaetzlich werden zur ersten Charakterisierung der mechanischen Eigenschaften Haertewerte bestimmt.
On 10 dialysis patients we performed 12 balloon dilatations, 2 catheter lyses, 6 stent implants (Palmaz stent) and one atherectomy of central venous stenoses or occlusions (v. subclavia, v. brachiocephalica) at the shunt arm of the patient. The primary success rate was, in balloon PTA and lysis, 12/14 interventions, and in stent placement and atherectomy 7/7. The angiographical and clinical primary result after stent implantation was significantly better than after conventional dilatation. After 66% of the balloon dilatations recidivation occurred within the first year; this can be treated by means of repeated PTA. Whether long-term exclusion of recurrence can be achieved by stent implantation, must be established by means of follow-up studies that are at present in progress. (orig.).
The deregulation of the power industry having been implemented at unparalleled pace in Germany, the marketers and utility managers have been faced with the challenge of coping within relatively short time with the whole range of problems involved in restructurisation in the emerging competitive and very dynamic market. The article summarizes the activities for reorientation and positioning in the market, laying the foundation for success in the future. The communication and IT infrastructure is a major aspect to be considered. The authors explain how the German power industry may profit from international experience and results, so as to gain time in pulling up with competitors in the international marketplace. (orig./CB) [German] Die Liberalisierung der deutschen Stromwirtschaft kann im internationalen Vergleich als einzigartig sowohl hinsichtlich ihrer Breite als auch ihrer Geschwindigkeit - volle Marktoeffnung fuer alle Kunden auf einen Schlag - angesehen werden. Die schnelle ...
In this study, the bend properties of the single-crystalline molybdenum brazed by using Mo-40%Ru alloys containing boron of 1-6 mass%Ru alloy for the improvement of the joint strength was determined. (orig.) [Deutsch] Durchgefuehrt wurde die Herstellung von Verbindungen aus einkristallinem Molybdaen. Hierbei kamen Mo-40%Ru-Legierungen mit 1 bis 6 Gew.-% Bor als Lotmaterialien zum Einsatz. Festigkeit und Duktilitaet der Verbindungen wurden mittels 3-Punkt-Biegepruefung bei Raumtemperatur und unter fluessigem Stickstoff ermittelt. Die Bruchflaechen der Proben wurden mit Hilfe eines Rasterelektronenmikroskopes untersucht. Die Ergebnisse lassen sich wie folgt zusammenfassen: Der optimale Borgehalt bezueglich Festigkeit und Duktilitaet der geloeteten Verbindung liegt bei 2 Gew.-%. Die entsprechende Probe hat bei einem Biegewinkel von 100 bei Raumtemperatur nicht versagt. Auch unter fluessigem Stickstoff zeigte diese Probe eine Festigkeit in der ...
The article deals with the following topics: reliability calculation as a basis of a maintenance strategy leads to the knowledge which equipment seems to be critical in the context of a supply interruption; procedure of a risk management; information for a risk assessment: probability of an equipment malfunction, reliability calculation on the system level, failure cost, maintenance cost, further conditions. The article shows an example for a calculation. [German] Die Zuverlaessigkeitsberechnung als Grundlage einer Instandhaltungsstrategie fuehrt zu der Kenntnis, welche Betriebsmittel kritisch im Hinblick auf eine Versorgungsunterbrechung sind. Eine anschliessende Risikobetrachtung schliesst deshalb neben der Betrachtung der nichtgelieferten Energie auch die uebrigen Kosten einer Stoerung ein, die mit den finanziellen Aufwendungen fuer eine Instandhaltung zu vergleichen sind. Im Folgenden wird ein Vorschlag fuer eine Risikobewertung von Hochspannungsbetriebsmitteln ...
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 ...
Zusammenfassung Seit Dezember 2009 ist in Deutschland neben einem 10-valenten (PCV10) auch ein 13-valenter Pneumokokkenkonjugatimpfstoff (PCV13) verf?gbar. Ein Wechsel von PCV7 zu PCV13 ist zu jedem Zeitpunkt einer begonnenen Impfserie problemlos m?glich, von PCV7 zu PCV10 nur bei der Boosterimpfung. F?r alle Kinder mit abgeschlossener vollst?ndiger PCV7- oder -10-Impfserie stellt sich die Frage, ob eine zus?tzliche Impfung mit PCV13 sinnvoll ist. Kinder mit erh?htem Risiko f?r Pneumokokkenerkrankungen gem?? STIKO (St?ndige Impfkommission am Robert?Koch-Institut), die mit PCV7, jedoch nicht mit PPV23 geimpft sind, sollten grunds?tzlich mit PCV13 geimpft werden. Zu diesen Risikokindern sind evtl. auch gesunde, aber bereits im fr?hen Alter in Gemeinschaftseinrichtungen betreute Kinder zu rec...
Until now, monitoring of power transformers focussed mainly large generator and network transformers. Siemens goes a step ahead and provides a system especially developed and designed for small and medium power transformers, e.g. for the 100 kV level. This low cost version could be achieved by restriction to really necessary measuring quantities. This allows to realize also for small and medium power transformers an online monitoring including an estimation of aging and as an option an early warning to avoid unexpected failures. (orig.) [German] Die Ueberwachung (Monitoring) von Leistungstransformatoren war bisher vor allem fuer Maschinentransformatoren und grosse Netzkuppeltransformatoren in der Diskussion. Siemens geht einen Schritt weiter und stellt nun auch ein System bereit, das speziell fuer kleine und mittlere Leistungstransformatoren, z.B. der 110-kV-Spannungsebene, konzipiert ist. Diese kostenguenstige Variante wurde durch Beschraenkung auf die aus ...
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 ...
We reported three cases of acute intracranial tuberculosis including miliary tuberculosis, basal meningitis, tuberculomas and neuritis of cranial nerves. All patients had native and contrast enhanced CT and MRI scans. MRI revealed more granulomas and a better imaging contrast in the detection of basal meningitis. Neuritis was diagnosed only with the MRI. MRI scans should be prefered as the imaging procedure in clinically presumed intracranial tuberculosis. (orig.) [Deutsch] Die Befunde von drei Patienten mit intrakranieller Tuberkulose (intrakranielle Miliartuberkulose, Meningitis tuberculosa, Neuritis und Tuberkulome) in der Magnetresonanztomographie (MRT) wurden mit der Computertomographie (CT) verglichen. Sowohl die MRT als auch die CT wurden nativ und nach Kontrastmittelgabe durchgefuehrt. Die MRT zeigte sich im Nachweis von Granulomen insbesondere im Bereich des Hirnstamms ueberlegen. Ebenso wurde ein hoeherer Bildkontrast bei der ...
Zusammenfassung Hintergrund Die vorliegende Arbeit untersucht, welche Frequenzkombination f?r die Berechnung der mittleren H?rverluste im Tonschwellenaudiogramm am besten mit dem H?rverlust f?r Zahlen im Sprachaudiogramm korreliert, da in der Literatur verschiedene Rechenvarianten f?r diese gutachterliche Plausibilit?tspr?fung beschrieben werden. Es wurden die 3?Rechenvarianten A (250, 500 und 1000?Hz), B (500 und 1000?Hz) und C (500, 1000 und 2000?Hz) verglichen. Methoden Die Audiogramme von 80?Normalh?rigen, 106?Schwerh?rigen und 135 zu Begutachtenden wurden retrospektiv analysiert. Die Differenzen der Mittelwerte aus dem Tonschwellenaudiogramm und dem H?rverlust f?r Zahlen wurden f?r das rechte und linke Ohr getrennt in den 3?Patientenkollektiven berechnet und statistisch verglichen. Er...
Until recently no active treatment for advanced or metastatic gastrointestinal stroma tumors (GIST) was available. The tyrosine kinase inhibitor imatinib has revolutionized the treatment of this disease and the median overall survival now reaches 5 years. The standard dose of imatinib is 400 mg per day. Locally advanced GIST should be treated with systemic therapy prior to surgical resection. Imatinib was recently licensed for adjuvant therapy following complete surgical removal of GIST in patients with a significant risk of recurrence. (orig.) [German] Bis vor einigen Jahren existierte keine wirksame systemische Therapie fuer fortgeschrittene oder metastasierte gastrointestinale Stromatumoren (GIST). Der Tyrosinkinaseinhibitor Imatinib hat die Behandlung dieser Tumoren revolutioniert, die mediane Ueberlebenszeit liegt heute bei etwa 5 Jahren. Die Standarddosierung von Imatinib betraegt initial 400 mg/Tag. Lokal fortgeschrittene Tumoren werden primaer systemisch ...
The new multi-purpose oxygen cupola furnace is a coke-fired shaft furnace that is operated on pure oxygen. The top gas is recirculated, and the fumes are drawn off at temperatures ranging from 800 to 1 000 C. The furnace offers the possibility of melting down contaminated and zinc-bearing scrap without the occurrence of any environment-polluting gas emissions. The absence of nitrogen ballast permits a high energy efficiency. (orig.) [Deutsch] Der neue Mehrzweck-Sauerstoff-Kupolofen ist ein koksbeheizter Schachtofen, der mit reinem Sauerstoff betrieben wird. Das Gichtgas wird im Kreislauf gefuehrt, und das Abgas wird aus einem Bereich mit Temperaturen von 800 bis 1 000 C abgefuehrt. Der Ofen bietet die Moeglichkeit, verunreinigte und zinkhaltige Schrotte einzuschmelzen, ohne dass umweltbelastende Gasemissionen auftreten. Der fehlende Stickstoffbalast bewirkt einen hohen energetischen Wirkungsgrad. (orig.)
An analysis on landscape level was performed to investigate the growth of Scots pine stands (Pinus sylvestris L.) in the research area of 'Duebener Heide' under the impact of rapidly changing pollution loads and to evaluate their further development. Central to the work was a spatial database, installed using a geographic information system (GIS). This database enabled the statistical analysis of relationships and correlations between the growth of the pine stands, the influence of pollution impacts and the natural site characteristics. The results of emission and immission modelling gave detailed evaluation of the pollution load over the investigated area. The spatial information database was linked with a process-based growth model called FORSANA. The resulting regional model was used to simulate forest growth on stand level for variable time periods. The plausibility of the simulation results of the model was checked for the influence of different patterns of ...
Suppliers of systems and components for compressed air technique were shown at the Hanover Fair 94 in Hall 5. On about 6000 m{sup 2} floor area, they showed their product range, which covered the whole range of compressed air technique from compressors via equipment for providing and storing the compressed air to compressed air tools. (orig.) [Deutsch] Die Anbieter von Systemen und Komponenten fuer die Drucklufttechnik waren auf der Hannover-Messe `94 in der Halle 5 zu finden. Dort zeigten sie auf rund 6000 m{sup 2} ihre Produktpalette, die von Kompressoren ueber die Geraete zum Aufbereiten und Speichern der Druckluft bis zu Druckluftwerkzeugen reichte und den gesamten Bereich der Drucklufttechnik abdeckte. (orig.)
Zone modeling permits taking account of the effect of load-relieving air conduction systems in the planning of HVAC plants. Although this only supplies average values for the degree of load and height of the fresh air layer rather than a detailed description of concentration and temperature distributions in the room, it is quite sufficient for the planning of load-relieving air conduction systems. Moreover, the cost of zone modeling in the planning of HVAC plants remains within reasonable limits. Upscale planning, instruments can thus be reserved for more exacting problems. (orig.) [Deutsch] Zonenmodelle erlauben die Wirkung lastmindernder Luftfuehrungen bei der Planung von RLT-Anlagen zu beruecksichtigen. Sie liefern zwar nur Mittelwerte fuer den Belastungsgrad und die Hoehe der Zuluftschicht und keine detaillierte Konzentrations- und Temperaturverteilungen im Raum. Diese Werte reichen jedoch fuer die Planung lastmindernder Luftfuehrungskonzepte aus. Zudem ist der ...
Internal combustion engines with mechanically driven superchargers are known for good performance at low engine speeds and fast response times under fluctuating loads. Application engineers can choose between superchargers with and without internal compression - the familiar roots (blower) type or true compressors - for supercharging an internal combustion engine. This article by DaimlerChrysler describes two options for improving the partial load behaviour of mechanically supercharged internal combustion engines with compressors. (orig.) [German] Die Aufladung mit mechanisch angetriebenen Verdraengerladern zeichnet sich durch guten Druckaufbau bei niedrigen Drehzahlen und gute Dynamik bei Lastwechseln aus. Fuer die Applikation am Verbrennungsmotor koennen Maschinen ohne innere Verdichtung - wie die bekannten Roots-Geblaese - oder Maschinen mit innerer Verdichtung - Kompressoren im eigentlichen Sinne - zum Einsatz kommen. In diesem Beitrag von DaimlerChrysler sind ...
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 ...
The investigations showed that the new adsorber/catalyst composites are well suited for chemical degradation of persistent water pollutants. Compared with alternative processes, the reaction selectivity and the consumption of oxidant are more favourable as the reaction now takes place on/inside the solid. The process, which was developed originally for purification of contaminated water, can be transferred to many other systems of materials. For example, it is expected that the soot emissions of diesel engines will be reduced significantly after efficient hydrogenation of the aromatics contained in the diesel engine on molybdenum-charged mesoporous composites. [German] Mit den vorliegenden Untersuchungen konnte ein erster Nachweis gefuehrt werden, dass die neu entwickelten Adsorber/Katalysator-Komposite fuer den chemischen Abbau persistenter Wasserschadstoffe geeignet sind. Im Vergleich zu alternativen Verfahrensloesungen kann die Selektivitaet der Reaktion und der Verbrauch an ...
Damage survey of protective coats of modern gas turbine blade shows that most damages are not due to classic wear mechanisms such as oxydation or high-temperature corrosion but caused by foreign bodies, poor coating during manufacturing, or operation-caused cracks. Mere visual inspection of cracks is often not sufficient to tell whether cracks are superficial or whether they have already progressed into the base material. Non-destructive methods such as ultrasonic inspection or eddy-current testing are helpful tools but there is not yet a fully matured testing concept at hand. Metallographical tests can give important information about crack mechanisms and thermal, chemical and mechanical stresses.(orig.) [German] Die Schadenerfahrung mit Schutzschichten moderner Gasturbinenschaufeln zeigt, dass die meisten Schaeden nicht auf die klassischen Verbrauchsmechanismen wie Oxydation und Hochtemperaturkorrosion zurueckzufuehren sind, sondern durch Fremdkoerper, herstellungsbedingte ...
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 ...
Since enterprises operating offices and facilities at geographically distributed sites have been establishing an intranet for inter-office communication at the management level, the idea of integrating another intranet for multi-site technological facility management comes naturally. The Aachen-based technology enterprise Eurem for this purpose developed a Network and Security concept with solutions that can be customized for linking a variety of computerized control and monitoring systems. The package includes a modular substation named modUS, which is open to the field side as well as to the management side, is capable of efficiently and reliably performing the facility management functions by way of remote controlling via intranets. (orig./CB) [Deutsch] Nachdem in den Unternehmen mit verteilten Liegenschaften die unterschiedlichsten Buerokommunikationssysteme ueber eigene Netzwerke verbunden werden, liegt es nahe, auch verteilte Gebaeudeautomationssysteme in diese Vernetzung ...
As an alternative to surgery, endovascular therapy with stent grafts has become the second main treatment option for infrarenal abdominal aortic aneurysms. Unlike surgery, endovascular treatment with stent grafts is also applicable in patients unfit for open repair. Despite current improvements in endovascular repair devices, significant anatomic barriers still exclude this technique for a large number of patients. Computed tomography, magnetic resonance imaging, and ultrasound are essential for diagnostics, preintervention planning, and postintervention follow-up of abdominal aneurysms treated with stent grafts. This review covers etiology, pathology, and diagnostic aspects. Materials and methods for endovascular treatment of abdominal aortic aneurysms are presented in detail, and clinical results and complications are discussed. (orig.) [German] Die endovaskulaere Therapie des infrarenalen Bauchaortenaneurysmas hat sich als Alternative zur offenen chirurgischen ...
Ventilation systems must ensure high room air quality with minimum energy consumption in all states of operation. Systems for ventilation on demand are increasing their market share. (orig./MSK) [Deutsch] Oberste Aufgabe von Raumlufttechnischen Anlagen ist die Sicherstellung guter Raumluftqualitaet bei minimalem Energieverbrauch unter allen Betriebsbedingungen. Um dieses Ziel zu erreichen, setzt sich am Markt zunehmend die bedarfsgeregelte Lueftung durch. (orig./MSK)
This report contains two sections. In the first section a limited review is presented and the preparation of the red mud based additives is described. The additives are characterized by composition and their catalytic activity in hydrocracking is investigated in a batch autoclave under an initial hydrogen pressure of 12 MPa at 435 C and 30 min residence time. A quantitative characterization of the products is given. Comparisons between the red mud additives and coke respectively a commercial catalyst are made. (orig.)
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 ...
Characterisation of the classification of brain tumours authorised by the WHO. Method of appraisal: This classification was revised and published in its second version. In the revision, some tumours were regrouped histogenetically and some tumour variants were added. Radiologically relevant changes of the classification include the differentiation of four new tumour entities that are easily distinguished by MR imaging. These four tumours belong to the group of childhood tumours or tumours occurring in early adulthood and are characterized by a good prognosis after extirpation. Results of appraisal: Central neurocytomas are small-cyst ventricular tumours associated with the foramen of Monroi and show moderate contrast enhancement. Infantile desmoplastic gangliogliomas/astrocytomas commonly consist of a solid tumour portion related to the leptomeninges with pronounced contrast enhancement and a typically very large cyst. Pleomorphic xanthostrocytomas are circumscribed cortical tumours ...
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 ...
In order to ensure a power balance in an electrical network a spinning reserve has to be capable of activation within seconds. However, because of the need to vary the fuel flow in the steam generator, the run-up of output takes minutes. The required capacity response is therefore achieved by storage of steam from the steam generator. In this process the turbine control valves come into action in a specific manner. The paper describes the importance of the initial reserve for unit capacity control. (orig.).
This report describes the QUEOS facility and gives the results of the first test series performed up to 6/1995. The premixing phase of a steam explosion is investigated experimentally with simulant materials. The transient three-dimensional multi-component interaction of molten corium with water is studied using a large number of small solid spheres at temperatures up to 2300 C. The objective of the experiments is to establish a data base for testing the models of heat and momentum transfer in multi-fluid codes as well as the code`s capability to correctly describe multiphase flows. The experiments have the advantage that the diameter of the `coarse melt fragments` are known and that detailed measurements can be performed without the danger of a steam explosion. In this first series of experiments up to 10 kg of spheres (max. 24000 pieces) were used. The spheres, made of molybdenum or zirconia, were heated to temperatures up to 2000 C and are discharged into 0.5 m{sup 3} of saturated ...
Westinghouse Electric Germany GmbH has developed fluid dynamic models for medium-actuated armatures using the thermal hydraulic code RELAP5 in order to reach a more realistic description of the armature behavior including fluid-structure interactions in case of transient flow conditions in piping systems. The contribution is concerned with the modeling of damped check valves. The model allows the description of the behavior during opening and closure of a check armature. The calculated results show good agreement with the available measured data.
60 patients between 17 and 72 years of age were investigated. First, an enteroclysis was performed in typical manner. The applicated methylcellulosis was blended with positive oral MR contrast media (Magnevist oral, Schering). After enteroclysis, MRI of the abdomen was performed using T1- and T2-weighted breathhold sequences (Flash 2D pre- and postcontrast and TSE) in axial and coronal planes. The length of the affected bowel and the stenosis seen with enteroclysis correlated well with the visible thickening of the small bowel wall and the stenosis seen in MRI. Using MRI, additional findings could be obtained in 28 patients, such as fistulas, abscesses or a hydronephrosis, or a better assessment of the stenosis was possible with MRI, because of the avoidance of overshadowing of the affected bowel loop with MRI. A brilliant MR-tomographic imaging of the small bowel is possible under the condition, that the small bowel contrast is optimal. The main prerequisite is a large filling volume ...
This thesis dealt with the metal-organic gas phase epitaxy with nitrogen as carrier gas. For this first by means of three-dimensional modelings of the epitaxy process the influence of the carrier gas on the processes was explained. The optimization of the growth parameter for the whole light-emitting-diode structure in double-hetero arrangement resulted that an a temperature of 770 C and a V/ III-ratio of 150 layers with a high crystal quality could be reached.
Smooth and notched specimens of the bearing steel 100Cr6 (SAE 52100) in a bainitic condition were used to determine the S-N-curves under tensile, torsional and combined in- and out-of-phase loading. In the area of high-cycle-fatigue, crack initiation was most likely caused by inclusions like Titanium Carbonitrides or Aluminium Oxides. A model was developed to describe the influence of the magnitude of these inclusions on the lifetime. A weakest link model, using the statistical distribution of inclusions and surface flaws, was used to describe the fatigue limit. (orig.)
The report covers the results of exposing materials for steam turbines to increased steam temperatures in two modules of the KOMET 650 testing facility at the Westfalen power plant. Ferritic/martensitic steels with 9 to 12% Cr and austenite and nickel-based alloys were investigated. Some experimental coatings on low-alloy Cr steel were also tested. The principal findings are presented. It will become possible to construct advanced power stations to be operated at higher temperatures. (orig.)
The restricted temperature stability of the synthetic thermal oil which is used as heat carrier fluid in parabolic trough collectors so far limits the live steam parameters in the steam cycle to approximately 375 Celsius. In order to break through this limit, already for quite some time it is researched to replace the thermal oil by boiler feeding waters and to accomplish the evaporation in the collectors. The contribution under consideration gives an overview on the direct evaporation concept and summarizes the past operational experiences. Moreover, the challenges with the integration of this technology in a steam turbine cycle are elaborated.
Two hypotheses are in the centre of this investigation, on the one hand the question, whether microwaves as exogenous fields alone are able to stimulate human muscle cells above-threshold, and on the other hand, whether microwaves as conditioning to cathodical electrical pulses can modify the excitation threshold and form. No excitation through the application of microwaves alone can be introduced at any subject. The conditioning of above-threshold cathodical electrical pulses with UMTS-microwaves leads not to a transgression of the threshold or the electrical muscle response (EMG) depending on the amplitude, the duration or the dose rate. (orig.)
Thermal solar energy plants for water heating have experienced an enormous boom during the last years. Thus, a total of 200000 square metres of collector surface was installed on German rooves in 1991. This was three times as much as in the year before. And this trend of conserving natural resources by using the energy of the sun is still undiminished. (orig.)
A Paderborn group of builder-owners decided in favour of so-called concrete core activation or isothermal component tempering as an alternative to conventional air conditioning. Results are now available for the first year of operation. [German] Am eigenen Neubau hat eine Paderborner Bauherrengemeinschaft die sogenannte Betonkernaktivierung - oder wie es die Bauherren nennen, isotherme Baukoerpertemperierung - als Alternative zu einer konventionellen Klimaanlage installiert. Inzwischen liegen die Messergebnisse von der ueber einjaehrigen Betriebszeit vor. (orig.)
The following questions, concerning the application of the harmonic oscillator representation (HOR) in the theory of scattering and reactions, are discussed: the formulation of the scattering theory in HOR; exact solutions of the free motion Schroedinger equation in HOR; separable expansion of the short range potentials and the calculation of the phase shifts; `isolated states` as generalization of the Wigner-von Neumann bound states embedded in continuum; a nuclear coupled channel problem in HOR; and the description of true three body scattering in HOR. As an illustration the soft dipole mode in the (11)Li nucleus is considered in a frame of the (9)Li+n+n cluster model taking into account three body continuum effects.
The legal basis to be provided is a licence for decommissioning work, issued for a particular reactor, including activities for recycling of disassembled, radioactive components and materials, subject to radioactivity measurements and exemption from radiological control of materials not exceeding the legally defined maximum level of contamination. (HP) [Deutsch] Es genuegt eine Stillegungsgenehmigung zu einem konkreten Abbauauftrag mit Verwertung radioaktiver Reststoffe nach Freigabe durch Radioaktivitaetsgrenzwertsfestsetzung. (HP)
Higher efficiencies of steam power plants are achieved by raising the operating temperature and pressure. The use of ferritic steels helps to minimize the cost and enhance the flexibility (two-shift operation, frequent starting and stopping). The COST programme had the long-term goal of developing and testing 9- 12 % Cr steels with high fatigue strength and to produce,test and operate critical components for an advanced steam power plant (steam temperature 600 C and supercritical pressure). (orig.)
Since mid-1995, Audi is the second European producer to offer a direct-injection diesel engine for passenger cars. The 2.0 l engine is installed in the middle-class sedan Rover 620 SDi. (orig.) [Deutsch] Als nach Audi zweiter europaeischer Hersteller bietet Rover seit Mitte dieses Jahres einen Pkw-Dieselmotor mit direkter Einspritzung an. Eingesetzt wird das Aggregat mit 2,0 l Hubraum in der Mittelklasselimousine Rover 620 SDi. (orig.)
The invention concerns the conversion of steam turbines, particularly condensation turbines, for the economic coupling of process steam and heating steam. The conversion occurs by retaining the basic construction of foundations, housing and bearings as support group and coupling member and matching the specially developed construction for the idea of use into the existing housing, and inserting the rotor into the shaft unit. By having the unchanged supports of the housing and the bearings of the shaft unit, the elasticity in expansion and the vibration behaviour of the turbine are retained and the conversion costs can be lowered.
There is increasing demand to functionalize meso- and nano-porous materials by coating and make the porous substrate biocompatible or environment friendly. However, coating on a meso-porous substrate poses great challenges, especially if the pore aspect ratio is high. In the current work the pulsed laser deposition (PLD) method is used for coating Ni{sub 3}Al-based meso-porous membranes with diamond-like carbon (DLC) layers of high thickness homogeneity and adhesion. (orig.)
We studied 129 AIDS patients with suspected or proved intracranial manifestations of the disease. The purpose of this study was to compare the diagnostic sensitivity of unenhanced and contrast enhanced CT and unenhanced T{sub 2}-weighted MR. Thus, in 20% of our patients MR but not CT was diagnostic. In another 20% MR provided additional diagnostic information. In conclusion, MR is recommended as the imaging modality of choice in AIDS patients with non-conclusive cranial CT. (orig./GDG).
Biogas supply to the public gas grid is a new option discussed in the most recent publication of Fachagentur Nachwachsende Rohstoffe (FNR) e.V. The biogas is purified, upgraded to natural gas quality and fed into an existing gas grid. Once there, it can be transported across long distances and also used for electric power generation at the consumer side. The study investigates inhowfar and in what instances this method is feasible and promising. It discusses the technical background and the regional potential of biogas. Seven model biogas systems are presented as examples. (orig.)
In the group of persistent aromatic hydrocarbons, the highest values were determined for polychlorinated biphenyls (PCB), total DDT and hexachlorobenzene (HBC). Comparisons of the relevant median values for the past six years led to the conclusion that the steep initial decline in the breast milk concentrations of DDT and HBC was followed by reductions at a much lower pace in the years after 1987. The time course of the concentration of the total PCB did not appear to follow any particular pattern. The mean contents of lead and cadmium remained by a wide margin below the threshold values for these heavy metals and thus were of no relevance from the toxicological point of view. It was found that the 134 and 137 cesium isotopes constituted no particular health hazard for breast-fed infants, as the relevant concentrations in breast milk were low. (VHE) [Deutsch] In der Gruppe der persistenten Chlorkohlenwasserstoffe werden die hoechsten Konzentrationen bei den polychlorierten Biphenylen ...
As a partner in this project, Siemens Power Generation investigated the crack propagation characteristics of short cracks in CMSX4. This involved crack propagation tests under dynamic and static load, creep tests on samples of different geometries, and life calculations, with the following results: No typical short cracking behaviour was observed under dynamic loads. Short crack propagation at 950 C under static load is well described by the fracture mechanical parameter C* integral. Notched bar creep tests showed longer times to cracking for notched bars. [German] In dem Verbundprojekt hat Siemens Power Generation u.a. die Untersuchungen von Rissausbreitungsverhalten von Kurzenrissen in CMSX4 als Hauptaufgabe bekommen. Dabei wurden Rissausbreitungsversuche unter dynamischer und statischer Belastung, Kriechversuche an Proben verschiedener Geometrie und Lebensdauerberechnung durchgefuehrt. Die wesentlichen Ergenisse sind wie folgt kurz ...
The purpose of the present study was to examine reactions between bromium atoms with {alpha}, {beta}-unsaturated carbonyls. Acrolein, methacrolein, and methyl vinyl zetone were chosen as representatives of this family. The latter two compounds, beside formaldehyde, belong to the main products of atmospheric oxidation of isoprene and have been detected in the troposphere at concentrations of up to almost 1 ppb. It is known that alkenes react with bromium via addition to form an instable adduct. This product can either decompose again into its educts or react with molecular oxygen. The aim of the study was to determine the velocities of the reactions between the three {alpha}, {beta}-unsaturated carbonyls and bromium and to clarify the involved reaction mechanisms by means of kinetic experiments and product analyses. (orig./SR) [Deutsch] In dieser Arbeit wurde die Reaktion von Bromatomen mit {alpha}, {beta}-ungesaettigten Carbonylen untersucht. Ausgewaehlt wurden ...
Molybdenum is an essential element for living organisms. Moreover its radionuclides may represent an incorporation risk for members of the public and/or radiation workers after a nuclear accident or a release of radioactive materials. However, only few reliable data on Mo biokinetics in humans were available. The results of recent tracer kinetic investigations with stable isotopes have shown several differences from the ICRP data with regard to the processes of intestinal absorption and of excretion. As a consequence, the dose coefficients calculated with a revised biokinetic model deviate from the ICRP estimates. By ingestion of {sup 99}Mo radionuclides with solid food, for example, the dose to the colon may be higher of a factor up to 1 order of magnitude, due to the fraction of non-absorbed material which traverses the gastro-intestinal tract. (orig.) [Deutsch] Molybdaen ist einerseits ein fuer Lebewesen essentielles Spurenelement, andererseits koennen radioaktive Mo-Isotope im ...
The enhancements described of high-performance CT systems of latest design have again confirmed the importance of CT systems for acute and selective diagnostic imaging. Higher availability, shorter exposure times, and better applicability and handling for examination of poly-traumata patients or patients of intensive care departments are some of the advantages achieved with CT systems which demonstrate CT system efficiency in addition to MRI, which for specific examinations will remain the modality of first choice for diagnostic evaluation. The Tomoscan Av-E presented here was able to answer all relevant diagnostic questions appearing in routine diagnostics and scientific work. For patients, examinations using the spiral CT technique also offers significant advantages. (orig./CB) [Deutsch] Durch die dargestellten Verbesserungen bei Hochleistungs-CT-Systemen neuester Bauart wurde die Bedeutung der CT fuer die akute und selektive Diagnostik erneut bestaetigt. Bessere Verfuegbarkeit, ...
High oleic acid sunflower oils have been commercially available for some years now. Due to their high content of monounsaturated fatty acids these oils have a number of potential applications in the oleochemical industry, especially where technical oleic acids and their derivatives are used. Whereas conventional sunflower oil contains approx. 68% linoleic acid (C{sub 1}8:2), it is now possible through breeding measures to obtain ''new sunflower oils'' (NSb oils) with oleic acid levels of 70-95% oleic acid (C{sub 1}8:1). The oil itself is of interest for technical applications: it is light-coloured, has a neutral odour and is relatively resistant to oxidation. Plant oils, especially those with a low content of polyunsaturated fatty acids, are increasingly gaining interest as ester oils in technical application areas, e.g. as lubricants. However, there are limits to the technical applicability of triglycerides due to their temperature behaviour or ...
Owing to their key function in power production the technology of gas- and steam turbines has a very high importance. Gas turbines in particular have become much more efficient and show higher performance in cogeneration plants. The VDI group on materials engineering puts these issues at the centre of this report whose focus is on measures necessary to increase plant availability: damage analysis, materials optimisation, supervision of construction and repair. The report which looks at applications and practical experience is adressed to operators of gas-, steam-, and water turbine plants, manufacturers of turbines and their components as well as maintenance companies, experts and insurance engineers. (orig.) [German] Aufgrund ihrer Schluesselposition bei der Stromerzeugung kommen den Gas- und Dampfturbinen eine sehr hohe technische Bedeutung zu. Insbesondere die Gasturbine macht in den letzten Jahren eine rasante Entwicklung im Hinblick auf Erhoehung von ...
For the transformation of gasoline direct injection concepts into production solutions not only fuel economy and emission potential but also system stability and durability is important as well as the optimized interaction with exhaust gas aftertreatment and engine management. By application of optical diagnostic methods on research engines and especially in real multicylinder engines, a DI gasoline combustion system could be developed meeting all these requirements. Its fuel economy in the lower part load range is found within the scatterband of DI-Diesel engines. Special emphasis has been concentrated on the optimum adaptation of the combustion system to the limited exhaust gas temperature range of the NOx storage catalyst technology. A combination of this DI gasoline concept with turbocharging reveals a high potential especially regarding transient response. (orig.) [Deutsch] Bei der Ueberfuehrung von Direkteinspritzkonzepten in reale Serienloesungen sind nicht ...
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 Verhalten ...
Purpose: To determine the diagnostic value of high resolution MR imaging with a circularly polarised (c.p.) body phased-array coil for the staging of pelvic lymph nodes in cervical carcinoma. Material and methods: 42 patients with histologically proven carcinoma of the cervix were studied on a 1.5 T scanner by using a c.p. body phased-array coil. The imaging protocol included T{sub 2}-weighted turbo-spin-echo (TSE) and T{sub 1}-weighted spin-echo sequences pre and post IV application of Gd-DTPA; slice thickness was 5-7 mm and pixel size 0.53 mm{sup 2}. Lymph nodes with a diameter of {>=}8 mm were considered to have metastatic involvement. MR imaging results were compared with histopathologic findings. Results: MR imaging showed enlarged lymph nodes ({>=} 8 mm) in 16 of 18 patients with histologic proof of lymph node metastases (sensitivity 89%). In 22 of 24 cases MR findings were true negative (specificity 92%). Diagnostic accuracy was 91%. Conclusion: High-resolution MR imaging ...
The amounts of lead and cadmium produced and processed in these days are considerable. As a result, our environment is increasingly polluted by heavy metals and industrial installations, motor vehicles or incinerating plants appear to be among the main culprits here. Air and water are the media permitting the entry of heavy metals into our natural environment where they accumulate in the soil and then gradually migrate into the plants. Their further transport in the food constitutes the third step in the environmental spread of heavy metals. The consumption of muscle and organ meats, of vegetables, fruits, canned food and drinking water is unavoidably associated with some ingestion of lead and cadmium. The degree to which they are taken up and stored in different tissues is determined by absorption properties and the nutritional state of the organism. Cadmium tends to accumulate in the kidneys, lead is mainly stored in the bones. A continuously increasing uptake finally results in ...
The report describes the processing of TiSi{sub 2}, MoSi{sub 2} and Ti{sub 5}Si{sub 3} by means of metal injection molding (MIM). First, the sintering activities of the three materials were investigated. After this, the viscosities of different mixtures of organic binder and powders of the three materials were determined, and in the final stage, components were produced by injection molding, the binder was removed, and the components were sintered. TiSi{sub 2} in powder form could be sintered to more than 95% of its theoretical density after 4 h at 1386 C. Metallographic analyses proved leaktightness of the component at this density. In the case of Ti{sub 5}Si{sub 3}, it was found that this material requires very long sintering times and high sintering temperatures for sintering to about 94% of its theoretical density. Metallographic analyses showed that only about 90% of the theoretical density was reached. MoSi{sub 2} in powder form could be sintered to only 90% of its theoretical ...
Methods: Systemic irradiation of neuroaxis is an essential part in the management of medulloblastoma, stPNET and intracranial germ cell tumors. The introduction of quality assurance programs in radiooncology assures a precise radiotherapy of target volumes and is a prerequisite to improve survival. Results: Hyperfractionated radiotherapy has the potential of increasing dose to tumor more safely without increasing the risk for late adverse effects. Pilot studies revealed excellent tumor control in medulloblastoma with acceptable acute toxicity and a long-term survival of up to 96%. In medulloblastoma stereotactic radiation techniques reveal an acceptable toxicity and promising results in tumor control in recurrent disease or as primary treatment. They are now part of future treatment protocols in case of persisting residual tumor. Radiotherapy alone in pure germinoma is continuously yielding high cure rates. In secreting germ cell tumors cisplatin containing chemotherapies in ...
A system for partial mechanisation of the support work with roadway driving machines consisting of a crawler undercarriage carrying a selective cutter with a cutting jib on a rotary tower is claimed. The system comprises a support manipulator movable in longitudinal direction over the rotary tower and cutting jib and a preassembly table with a number of brackets to take up and preassemble a support structure consisting of profile segments, preferably an arc-shaped support with a cap made up for several parts. The system is characterized in that the preassembly table is mounted on one side of the selective cutter and has one straight vertical guide bar each for at least two cap brackets which can be continuously adjusted in height, and in that the manipulator mounted on the selective cutter has a horizontally suivelling head which may grip under the cap of the preassembled structure on the preassembly table.
Sprengel deformity is a congential malformation with usually unilateral elevation and medial rotation of the scapula. An omovertebral bone is generally present. Associated skeletal malformations are frequently present. Though functional impairment is mild, the cosmetic and psycho-social impairment can be considerable. The prognosis of early surgical therapy is good. The presented case also justifies surgical correction in the older child. (orig.) [German] Die Sprengel-Deformitaet ist eine angeborene Fehlbildung mit meist einseitiger Elevation und Medialrotation der Skapula. Meist ist ein Os omovertebrale vorhanden. Assoziierte skelettale Fehlbildungen sind haeufig. Obgleich funktionell wenig einschraenkend, ist die kosmetische und psycho-soziale Beeintraechtigung oft erheblich. Die Prognose der fruehen operativen Therapie ist gut. Der vorliegende Fall ermutigt zur operativen Therapie auch im hoeheren Kindesalter. (orig.)
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)
In the context of the research project, the physical basis of the direct decoupling of highly concentrated solar radiation in materials without the detour via absorbing heat exchanger walls was examined. Also, the first chemical processes suitable for the effective long-term storage of solar energy were analysed, relevant experiments were carried out and the necessary receiver techniques for high temperature applications were provided. The principle of direct coupling was examined on fluidized beds on the one hand and on cavity receivers, on the other hand. The contribution shows the results achieved in detail. It is recorded that first processes for storing solar energy in chemical reactions were able to be examined. Alkaline earth hydroxides accommodated in ceramic honeycomb structures seem to be possible as stores for medium temperature ranges around 500deg C. Investigations on receiver structure materials are also making progress. Highly transparent, high temperature-resistant ...
A patent is claimed for a process by which a low-hydrogen gas containing at least 90 percent by volume of methane which is suited for natural gas substitution is produced by transformation of vaporizable hydrocarbons with the aid of steam in the presence of a catalyst containing nickel, at temperatures of 350 to 600/sup 0/C and at increased pressure. Hydrocarbons and steam are supplied to the reaction in mixed form with recycle product gas. Per kilogramme of hydrocarbons to be converted in the high btu gas reactor, less than 1 kilogramme of fresh steam is needed. High btu gas is fed back from the high btu gas reactor to the input end of the same via a gas cycle comprising a cooler, a carbon dioxide absorption device, and a saturator. Between the carbon dioxide absorption device and the saturator a product gas is branched off which may pass a methanation device.
The MRI morphology in combined subacute degeneration has only rarely been reported. We describe two patients suffering from subacute combined degeneration of the spinal cord on the basis of a deficiency of vitamin B{sub 12}. In both patients characteristic hyperintense areas on T{sub 2}-weighted images in the posterior columns of the cervical and thoracic cord without contrast enhancement were demonstrated by MRI. (orig.) [Deutsch] Bisher liegen zur wenige Beschreibungen der MR-Morphologie bei funikulaerer Myelose vor. Wir beschreiben zwei Patienten mit den klinischen Zeichen einer funikulaeren Myelose auf der Basis eines Vitamin B{sub 12}-Mangels. Bei beiden konnten mit der MRT charakteristische Signalanhebungen im T{sub 2}-gewichteten Bild in den Hinterstraengen des zervikalen und thorakalen Rueckenmarks gezeigt werden. Eine Kontrastmittelaufnahme war nicht nachweisbar. (orig.)
The liberalisation of the energy markets requires completely new demands to the information processing procedure of energy supply enterprises. These requirements are to be understood as chances for strengthening of the terms of competition. In the following contribution to this subject the actual status of the concept as converted by the Electricity Supply Company of Halle (Saale) including their departments of district heating, gas and electricity supply will be presented. This concept are comprising all experiences as gathered so far as well as intended further actions to be executed. (orig.) [German] Die Liberalisierung der Energiemaerkte stellt fuer Versorgungsunternehmen voellig neue Anforderungen an die Informationsverarbeitung. Diese Anforderungen sind als Chancen zur Staerkung der Wettbewerbsfaehigkeit zu verstehen. Die Verfasser erlaeutern den aktuellen Stand des in der EVH GmbH Halle (Saale) im Querverbund der Sparten Fernwaerme, Gas und Elektrizitaet ...
The technical potentials of electric power generation from hydro power in Germany, the current harnessing of hydro power, its costs, and certain characteristic quantities reflecting its effects on the environment are described. These diverse characteristic quantities are compared with those of other renewable and fossil energy sources used to generate electricity. On this basis, opportunities for extending the use of hydro power in Germany and its limits are discussed. (orig.) [Deutsch] Das Ziel der folgenden Ausfuehrungen ist, die technischen Potentiale und deren derzeitige Nutzung, die Kosten und bestimmte die Umwelteffekte beschreibende Kenngroessen einer Stromerzeugung aus Wasserkraft in Deutschland darzustellen. Diese unterschiedlichen Kenngroessen werden anschliessend mit denen anderer regenerativer Energien und fossiler Energietraeger zur Stromerzeugung verglichen. Ausgehend davon werden die Moeglichkeiten und Grenzen einer weitergehenden Wasserkraftnutzung ...
The adaption of the Muster-VAwS (model ordinance on the handling of water endangering substances in plants and specialized facilities) in the ordinances of the different German states, means that the legislator has laid down concrete - technical and organizational - requirements concerning the handling of water-endangering substances for all plants. The present example of the systematic stocktaking of all environmentally relevant substances in the context of the operation of the pumped storage plants of Schluchseewerk AG, Freiburg, an the application of the model operating instructions for hydropower plants shall serve to illustrate two important aspects for the implementation of this extensive ordinance. (orig.) [Deutsch] Durch Umsetzung der Muster-VAwS (Muster-Verordnung ueber Anlagen zum Umgang mit wassergefaehrdenden Stoffen und Fachbetriebe) in entsprechende Laenderverordnungen wurden durch den Gesetzgeber konkrete Anforderungen, technisch und organisatorisch, fuer alle Anlagen ...
The second volume contains a comprehensive presentation of inflammatory bone diseases, including seldom primary chronic osteomyelitis and morbus Paget. Substantial chapters on bone tumors and tumor-like lesions of bone joints are covering the state-of-the-art of diagnostic techniques of these seldom but important diseases. Besides the importance of projection radiography the contribution of MRI within differential diagnosis und staging of these diseases is emphasized. [German] Der zweite Band des Muskuloskelettalen Systems befasst sich mit der umfassenden Darstellung zur Diagnostik entzuendlicher Knochenerkrankungen und beinhaltet neben den klassischen infektioesen auch die seltenen, primaer chronischen Osteomyelitiden und den Morbus Paget. Umfangreiche Kapitel ueber die Knochentumoren und tumoraehnlichen Laesionen der Gelenke stellen in modernster Weise den aktuellen Stand des Wissens und der Diagnostik dieser seltenen, aber aus differenzialdiagnostischer Sicht ...
In the course of the research project 'Investigations of trace element concentrations in coal seams with different mineral groups', 31 seam coals of the Ruhr Carboniferous were analysed in order to determine the bending of 14 coal-relevant trace elements to the mineral groups and/or minerals of the coals. Products with different ash content were produced by fluctuation of the seam coals in a laboratory cell. The raw coals and fluctuation component products were analyzed chemically and mineralogically in order to get a quantitative raw material characterisation of the sampled material. Particular interest is taken in the chemical and non-ecological composition of the mineral as ash carrier in the coal and the fluctuation component products, as well as in trace element control. (orig./EF).
In car parks of considerable length, the removal of exhaust emissions, is carried out by air-conditioning systems mainly through transverse ventilation over short routes. The required air-conditioning ducts frequently produce a reduction in the available parking space simply due to their presence, resulting in restrictive effects on the level of acceptance by the users. In such cases, remedial action can be taken by creating ductless longitudinal ventilation. Depending on the required room air quality in the zones with the highest level of pollution, the volumetric flows for longitudinal disposal are no greater than those for conventional transverse ventilation. In conjunction with architecturally clear and positive lighting designs, clearly laid out car parks with a friendly atmosphere can be created which the user will be pleased to accept. (orig./BWI)
The pilot project of the conversion of the green forage drying plant Lengenfeld to biomass firing could not be realized without problems. But the experience until now shows that it is in principle possible. The farmers involved are devoted to the project. For them the cultivation of biomass is an alternative to the abandonment of fields. The present low oil price sets limits to the positive income effect. The aim is an increase of the biomass share in heating energy supply to about 80%. (orig.) [Deutsch] Die Umstellung der Gruenfuttertrocknung Lengenfeld auf Biomassefeuerung ist als Pilotprojekt nicht ohne Probleme moeglich gewesen. Die bisherigen Erfahrungen zeigen jedoch die grundsaetzliche Praktikabilitaet. Die beteiligten Landwirte sind engagiert bei der Sache und schaetzen die Produktionsmoeglichkeit als Alternative zur Flaechenstillegung. Der derzeit niedrige Oelpreis setzt der positiven Einkommenswirkung jedoch enge Grenzen. Eine Erhoehung des ...
A new material has been developed for welded low-pressure shafts in steam turbines. Nine test welds were examined in order to confirm the chemical analysis. A shaft disc with an optimized composition was produced and destructively tested. The new material demonstrates, both in a total forging and also in a joint weld examined, excellent strength and toughness characteristics as well as excellent resistance to corrosion. Accordingly, all the requirements for welded low-pressure shafts in steam turbines are fulfilled. (orig.) [Deutsch] Fuer geschweisste Niederdruckwellen in Dampfturbinen wurde ein neuer Werkstoff entwickelt. Zur Festlegung der chemischen Analyse wurden 9 Versuchsschmelzen untersucht. Mit optimierter Zusammensetzung wurde eine Wellenscheibe hergestellt und zerstoerend untersucht. Der neue Werkstoff zeigt sowohl im gesamten Schmiedestueck als auch in einer untersuchten Verbindungsschweissung gute Festigkeits- und Zaehigkeitseigenschaften sowie gute ...
Melting in a cokeless cupola furnace fuelled with natural gas is a novel, energy-saving and environment-friendly process. In order to be able to monitor the processes inside the furnace with detailed mass and heat balances, an experimental furnace with an efficient measuring system was constructed in the framework of a research project financed by the BMFT and Messrs. Eisenwerke Dueker GmbH und Co. KG, Laufach, Germany. (orig./HS) [Deutsch] Das Schmelzen im kokslosen erdgasgefeuerten Kupolofen ist ein neues, energiesparendes und umweltfreundliches Verfahren. Um die Vorgaenge im Ofen mit umfassenden Stoff- und Waermebilanzen erfassen zu koennen, ist im Rahmen eines vom BMFT und der Firma Eisenwerke Dueker GmbH und Co. KG, Laufach, finanzierten Forschungsvorhabens, ein Versuchsofen mit umfangreicher Messeinrichtung gebaut worden. (orig./HS)
Since June 1990, the IMA ``CO2 Reduction`` has been working on a German air pollution abatement programme. Four reports were submitted in this period. The contribution presents the fourth of these reports. The measures taken, their state of implementation and the expected effects in 2000 and 2005 are presented in table form. (orig.) [Deutsch] Seit Juni 1990 befasst sich die Interministerielle Arbeitsgruppe ``CO2-Reduktion`` (IMA ``CO2-Reduktion``) mit dem deutschen Klimavorsorgeprogramm und hat seither vier Berichte vorgelegt. Im Folgenden werden neben der Ausgangslage und den Grundlagen fuer den 4.Bericht der IMA ``CO2-Reduktion`` die wesentlichen Inhalte des 4.IMA-Berichts dargelegt. In Tabellenform werden die einzelnen Massnahmen, ihre Art, der Umsetzungsstand sowie der erwartete Effekt in 2000 bzw. 2005 dargestellt.
Modernisation of older office buildings commonly includes installation of air conditioning systems as good air quality and thermal comfort will improve the staff`s efficiency at work. However, what about tenants who want their own, individually controlled single-storey air conditioning plang? And what about retrofitting further storeys with single-storey air conditioning? An exemplary solution to this problem was found in Hamburg. (orig.) [Deutsch] Bei der Sanierung aelterer Buero- und Geschaeftshaeuser werden die Raeume immer haeufiger mit Klimaanlagen ausgestattet. Ein Grund fuer den Trend zur Klimatisierung: Gute Luftqualitaet und angenehme Temperaturen erhoehen die Leistungsfaehigkeit des Menschen. Was aber, wenn ein Mieter fuer seine Bueroetage eine eigene, individuell steuerbare Klimaanlage wuenscht? Und was passiert, wenn andere Bueroetagen mit weiteren Klimaanlagen nachgeruestet werden? In Hamburg wurde dieses Problem auf beispielhafte Weise geloest. ...
A method was developed in which the potential of various measures is assessed systematically with a view to meeting the future EU5 emission specifications. Varied boundary conditions are taken into account, and their influence on the PM-NOx tradeoff was investigated. The relative cost is compared to an existing EU4 injection system. It was attempted to apply these measures to the impending US regulations (Tier2 Bin5) and to offer an outlook to EU6. The result shows that it is possible in principle for a car of the 1600 kg class to reduce NOx emissions while maintaining the EU4-PM emission standards.In the case of envisaged serial application subject to emission standards like US Tier 2 and EU6, much work is still required in terms of system robustness and life. In higher-class vehicles, the NOx reduction potential is lower, and it will be more difficult to make do without NOx treatment, especially with the NOx emission standard of US Tier2. (orig.)
Primary malignant lymphoma of the brain is a disease of unknown etiology, which is increasing in incidence and has an unfavorable prognosis. Despite the lack of specific changes on CT or MRI in most cases, these procedures may typically facilitate the diagnosis: A focal-enhancing mass with subependymal spread on CT or MRI and hyperattenuation on nonenhanced CT are the most reliable features in the diagnosis of primary malignant lymphoma of the brain. Peritumoral edema and mass effect are usually not prominent features. On unenhanced CT scans they usually appear homogeneously isodense to mildly hyperdense relative to the gray matter. On MRI these tumors are slightly hypointense on T1-weighted images and slightly hpyerintense on PD- and T2-weighted images relative to the gray matter. On CT and MRI enhancement is usually homogeneous. Contrast-enhanced MRI, with its multiplanar capability, lack of bone-induced artifacts, and high-contrast resolution, is likely to reveal subependymal spread ...
This report completes the documentation for the research project 'High Pressure Compressor - Preliminary Design as Basis for the Development of an Efficient and Environmentally Friendly Core Engine' which was funded by the Ministry of Economics of State Brandenburg. The objective of the project is to deliver a preliminary compressor aerodynamic design as well as design studies for an efficient, weight and cost improved compressor. The increase of stage pressure ratio and improved efficiency, whilst stage and blade count is reduced, has been achieved by advanced 3D methods. Compressor stability also at off-design conditions will be retained. The mechanical design focusses on a cost and weight optimised rotor not only for a conventional bladed discs but also for Blish stages. Various options for split casings have been developed and assessed. Alternative vortex reducers based on different design options have been carried out. The results from this project will be ...
To test the assumption underlying every morphometric twin study that the brains of monozygotic twins are almost identical. Methods: High resolution MRI of the neurocranium of 26 monozygotic twin pairs were acquired and the volumes of 36 cerebral structures were measured. The same twins served as control group after rear-ranging them into non-related pairs of same sex and matching them for age, body height and body weight. Results: For most of the examined structures the correlations within the twins were significant (R = 0,97-0,59). Except for total forebrain volume the controls showed no significant similarity. Conclusions: For almost every measured cerebral structure the assumption, that significant similarities exist between healthy monozygotic twins is correct. Therefore discordant monozygotic twins represent an excellent sample when investigating cerebral correlates of neurologic and psychiatric disorders. (orig.) [German] Pruefung der Grundannahme hirnmorphologischer ...
A singular stress field can occur at the edge of the joint plane in a thermally or mechanically loaded material compound. This stress field was calculated analytically and was compared with the results from the finite element method. If one of the two partners consists of ceramic material, unstable crack spread starting from faults in this strongly stressed area can lead to failure. In linear elastic material, the behaviour of a crack is clearly described by the stress intensity factors. These can be calculated for a known stress distribution in the uncracked structure by the method of the weight function. The corresponding weight functions for surface cracks parallel to the boundary surface were determined with the aid of suitable reference load cases. The effect of the position of the crack in the compound and the elastic constants of the compound are discussed. For examples, the stress intensity factors for cracks in a thermally stressed material compound were determined by the ...
Preserving customers` investments in capital goods is one of the strategic market services offered by ABB, and to this end the company has developed project-specific retrofit concepts especially for older power generation plant. A prime example of such a modernization is the Umm Al Nar East (UANE) combined cycle power station in Abu Dhabi, UAE. UANE has two gas turbines of type GT13D, which together generate 140 MW of electrical energy, and heat-recovery boilers which supply steam to a seawater desalination plant with a capacity of 80 million liters of drinking water per day. After almost 20 years in operation, UANE is being modernized. To address the owner`s concerns and minimize plant downtime, ABB has introduced Service, Operation and Rehabilitation (SOR) Key Account Management for Abu Dhabi. In the first phase of the modernization project, the static starting equipment was upgraded and the mechanical turbine governor replaced by the EGATROL electro-hydraulic control system. Also, ...
On the basis of cylindrical roller thrust bearings it was systematically examined to what extent PVD-coatings are able to take over the function of EP/AW-additives. The bearings were tested under heavy-duty conditions in order to distinguish very fast the efficiency of different coating-substrate-systems. Several coatings were tested for their ability to protect an un-coated counterpart. So just the washers of the roller bearings were coated, the rollers stayed un-coated. Four Me-C:H-coatings showed the best performance and fulfilled the required criterion for roller bearings in the boundary friction: low loss of mass and hardly surface deviation. Material carryover from the carbonaceous coating to the 100Cr6 steel surface was developed by the Me-C:H-coatings during the tests. This mechanism was able to protect the un-coated rollers. Closer investigations were done with an ESMA analysis (electron beam micro range analysis) on ZrC{sub g}-coatings. It could be seen, that a reaction layer ...
A new generation of lead alloys for making lead batteries is being introduced in highly developed countries. A very important characteristic of these alloys is the presence of Ca, Al and Sn. Such alloys have the property of stabilizing the amount of gas emitted as a result of the decomposition of the electrolyte on the level of pure lead i.e. significantly smaller than lead alloys containing Se e.g. PbSb 1.7Se. Such alloys have not been produced in Poland so far. - In this paper we are presenting the method and equipment used to produce a pilot portion of PbSnCaAl alloy (mass approximately 80 Mg) on an industrial scale at HMN ''Szopienice'' S.A. lead refinery. We also present the results of the tests regarding the chemical homogeneity of the alloy produced, as well as its structural and casting properties. On the basis of the tests conducted it has been found that the method is industrially adequate and as such it has been introduced into the ...
The aim of the presented investigation was to gain information about the behaviour of the initiation and growth of intercrystalline creep cracks during creep deformation from the evaluation of metallographic micrographs. The austenitic steel X10 NiCrAlTi 32 20 HT (Alloy 800 HT) was investigated by carrying out creep tests at 800 and 900 C with different nominal stresses until fracture. Additional tests are carried out on certain creep strains in the late tertiary creep stage. The creep tests are followed by a metallographic investigation of the crept specimens. The statistical distribution of the microcrack lengths was used to estimate the rate of crack initiation and crack growth. It is found that the rate of growth of the intercrystalline creep cracks in Alloy 800 HT is dependent on the applied stress and the creep strain reached. The rate of growth of long cracks was only slightly higher than that of short cracks and was lower than predictions based on fracture mechanics concepts. ...
For a wider application of GaAs single crystals for semiconductor devices a cheaper process to grow crystals with high purity and low dislocation density is required. According to todays knowledge the Czochralski method with a hot wall vessel should be the choice. The temperature of the vessel has to be 700deg C to avoid condensation of arsenic which vapourizes from the 1240deg C hot melt. Arsenic vapour is very agressive against all metals. Therefore the corrosion resistance of metals and alloys with a high melting point and also ceramics has been tested. All the alloys under investigation are corroded severely so that they have to be excluded as a material for the vessel. The metals tantalum, molybdenum and tungsten are more resistent, titanium forms initially a thick protection layer and further corrosion is greatly reduced. The ceramics investigated (TiB{sub 2}; ALN; Makor; BN) are not attacked by arsenic though they may store some arsenic. (orig./MM). [Deutsch] Fuer breitere ...
Within the framework of efforts to optimize state-of-the-art waste disposal methods, this research project makes a theoretical analysis of the propagation behaviour of pollutants from landfills and waste incineration plants into the immediate vicinity of such plants. In order to judge the propagation of pollutants near the above-mentioned waste disposal facilities, a calculation program was developed within the framework of this research project which permits simulation of the propagation of such emissions in a three-dimensional space by application of an Eulerian grid model. It is capable of realistically representing fluid flow conditions and pollutant concentrations for certain points of times within the complex building patterns of such plants, for randomly chosen atmospheric conditions. (orig.)
There are no 'intelligent' buildings but only 'intelligently controlled' buildings. Intelligent control requires communication between technical facilities, which in turn requires building automation and system integration. [German] Es gibt keine ''intelligenten'', sondern nur ''intelligent betriebene'' Gebaeude. Mit dieser Feststellung ist die Vorbedingung festgelegt, dass Gebaeude ein gewerkeuebergreifendes System benoetigen, das die Komponenten miteinander kommunizieren laesst. Dafuer eignet sich die Gebaeudeautomation. Damit diese ihre Aufgaben erfuellen kann, bedarf es der Systemintegration. (orig.)
The experimental survey about the heat transfer between the working fluid and the combustion chamber wall with a direct injection diesel engine has shown the production of a soot layer with increasing loads on the combustion chamber wall. Because the combustion process of methanol occurs without the formation of wall deposits, the same engine spark ignitioned with methanol at the same conditions has shown a higher heat transfer coefficient. Because the heat losses do not only depend on the heat transfer coefficient but also on the driving temperature difference between the working fluid and the combustion chamber wall, the methanol engine with corresponding process management showed lower heat losses than the diesel engine at nearly the same load. (orig./HW)
We investigate the relation between the symmetries of a quantum system and its topological quantum numbers, in a general C*-algebraic framework. We prove that, under suitable assumptions on the symmetry algebra, there exists a generalization of the Bloch-Floquet transform which induces a direct-integral decomposition of the algebra of observables. Such generalized transform selects uniquely the set of "continuous sections" in the direct integral, thus yielding a Hilbert bundle. The emerging geometric structure provides some topological invariants of the quantum system. Two running examples provide an Ariadne's thread through the paper. For the sake of completeness, we review two related theorems by von Neumann and Maurin and compare them with our result.
Fatigue tests were accomplished with a series of specimens doped with trace elements of a hardened Fe-Ni-Cr alloy, cast and hardened with intermetallic phases for determining the influence of these elements on the high temperature strength properties. The results of extensive fatigue tests show that even small contents of Te, Bi, Se, Pb, Tl and Zn considerably influence the life and creep processes especially after longer running periods, when added individually or combinedly. In contrast to this, the fatigue ductility is reduced by trace element additions even with short running periods. The order in which the metallic trace elements influence the fatigue properties nearly correlates with earlier work concerning Ni- and Co-superalloys. (orig.)
In the future even more than in the past, nuclear power will be indispensable in the present industrialized countries and in those still under development. The safe, nonpolluting, and economic supply of energy to mankind in the future includes so many different problems that the technology of the high-temperature reactor at its present level of development, and with the possibilities is offers above and beyond those provided by other, established, technologies, does not have to mark the end of some old line of development, but rather should be seen as the starting point of a development offering promise for the future. It is for this very reason that the extensive, valuable knowledge and experience accumulated in the construction, operation, and decommissioning of the AVR and THTR plants, the development of the HTR module and other variants and, last, but not least, the valuable results of projects such as PNP, NFE, and HHT, must be preserved at the research centers and with former ...
This final report for the Swiss Federal Office of Energy (SFOE) presents the results of a project that involves the building of a joint biogas plant serving 60 farmers and industrial companies with an annual processing capacity of 45,000 tons. The plant is to produce biogas to be fed into the gas mains and will not only reduce nutrient loading in a region with an extensive livestock industry but also reduce carbon dioxide emissions by using the gas as a motor fuel. The importance of the project with respect to both the environment and energy policy-making is discussed and the costs involved are examined. Details are presented on the technology used and on the material flows involved. Figures are quoted on energy production. The various biogenic substrates used, such as food wastes, waste oils, cereal wastes and used mushroom substrates, are discussed, as is the use of the solid and liquid outputs of the digester in farming activities.
In this article, the ability of artificial neural networks in prediction of separation in steady two dimensional boundary layer flows is studied. Data for network training is extracted from numerical solution of an ODE obtained from Von Karman integral equation with approximate one parameter Pohlhousen velocity profile. As an appropriate neural network, a two layer radial basis generalized regression artificial neural network is used. The results shows good agreements between the overall behavior of the flow fields predicted by the artificial neural network and the actual flow fields for some cases. The method easily can be extended to unsteady separation and turbulent as well as compressible boundary layer flows. (author)
In this article, the ability of artificial neural networks in prediction of separation in steady two dimensional boundary layer flows is studied. Data for network training is extracted from numerical solution of an ODE obtained from Von Karman integral equation with approximate one parameter Pohlhousen velocity profile. As an appropriate neural network, a two layer radial basis generalized regression artificial neural network is used. The results shows good agreements between the overall behavior of the flow fields predicted by the artificial neural network and the actual flow fields for some cases. The method easily can be extended to unsteady separation and turbulent as well as compressible boundary layer flows. (author)
The following method is proposed as a supplement to main patent 2419107, which deals with the filling of tubular plates surrounding the lead cores: the flat materials which are used to produce the jacket tubes are prepared before forming into jacket tubes by a film producing aqueous carboxy-methyl cellulose solution closing the pores. The preparation can be done by coating the flat material with a soluble foil. After pressing the paste in, the tubular plates are dried and after cooling are dipped into sulphuric acid with a specific gravity of 1.24 g/cm/sup 3/. The carboxy-methyl cellulose is dissolved and the permeability of the tube walls for electrolyte is restored after only 15 minutes.
The experimental technique used for detection of subcooled boiling through analysis of the fluctuation contained in pressure transducer signals is presented. This work was partly conducted at the Institut fuer Kerntechnik und zertoerungsfreie Pruefverfahren von Hannover (IKPH, Germany) in a thermal-hydraulic circuit with one electrically heated rod with annular geometry test section. Piezo resistive pressure sensors are used for onset of nucleate boiling (ONB) and onset of fully developed boiling (OFDB) detection using spectral analysis/ signal correlation techniques. Experimental results are interpreted by phenomenological analysis of these two points and compared with existing correlation. The results allow to conclude that this technique is adequate for the detection and monitoring of the ONB and OFDB. (author)
The experimental technique used for detection of subcooled boiling through analysis of the fluctuation contained in pressure transducer signals is presented. This work was partly conducted at the Institut fuer Kerntechnik und zertoerungsfreie Pruefverfahren von Hannover (IKPH, Germany) in a thermal-hydraulic circuit with one electrically heated rod with annular geometry test section. Piezo resistive pressure sensors are used for onset of nucleate boiling (ONB) and onset of fully developed boiling (OFDB) detection using spectral analysis/ signal correlation techniques. Experimental results are interpreted by phenomenological analysis of these two points and compared with existing correlation. The results allow to conclude that this technique is adequate for the detection and monitoring of the ONB and OFDB. (author)
Differentiating a benign from a malignant lesion by information such as density data, or signal intensities or echo gradients, is not possible with CT, nor MRI, nor ultrasonography. Only some lesions show characteristic signs. Inflammations cannot be difscriminated from malignant tumors. CTs of small tumors in particular are so poor in contrast that it is much more difficult to detect tumors or discriminate them from other lesions, as compared to MR images or ultrasonographs. CT does not detect surface tumors, but is more sensitive than MRI or US in detecting discrete cortical bone lesions. The same applies to small calcified tumors. MRI however is most sensitive in detecting tumor volumes in the yellow marrow, and is the best modality for evaluation of extraossal extension of tumors. CT yields better results than MRI if applied for simultaneous screening of lymph node metastases in the lower neck. MRI frequently is spoilt by movement artefacts. High-resolution, contrast enhanced CT ...
Magnetic pulse welding, a cold solid state bonding process, is becoming a viable replacement for conventional fusion welding processes and explosive welding. The process is presented here along with its fundamental equations and applications of similar and dissimilar welds are illustrated along with typical interface microstructures. (orig.) [German] Magnetimpuls-schweissen, ein Verbindungsverfahren im kalten Festzustand, wird ein funktionsfaehiger Ersatz fuer das herkoemmliche Schmelzschweissverfahren und das Explosionsschweissverfahren. Das Verfahren wird hier mit seinen grundlegenden Gleichungen vorgestellt, und Anwendungen von aehnlichen und unaehnlichen Schweissungen werden mit typischen Schnittstellen-Mikrostrukturen veranschaulicht. (orig.)
Zusammenfassung Eine genauere Untersuchung der bekannten Modelle isotropen Materialverhaltens (z.B. von Mises, Tresca, Mohr-Coulomb, Drucker-Prager usw.) zeigt, dass sie selten mit Versuchsergebnissen ?bereinstimmen. Modelle mit inkompressiblen Eigenschaften sch?tzen oft das Materialverhalten bei mehraxialen Zugbelastungen falsch ein. Beim Flie?en unter Druck liefern die Modelle mit kompressiblen Eigenschaften unzul?ssige Werte der Querkontraktionszahl. Erfahrungen zeigen, dass es schwierig ist, mehrdimensionales Materialverhalten bei h?ufig fehlenden Informationen werkstoffgerecht abzubilden. Viele Modelle liefern akzeptable Ergebnisse nur f?r bestimmte Bereiche des Spannungsraumes. Diese Beobachtung hat auf die Idee gef?hrt, ,,bew?hrte?? Modelle miteinander zu verbinden. In diesem Artike...
In a water well sunk in the Grafschaft Bentheim region of northern Germany, small volumes of methane were emitted regularly and large volumes of methane in eruptions at irregular intervals. After some extreme gas eruptions in 2002 and 2004, the Grafschaft Bentheim district government initiated a project to investigate underground conditions in the region between Nordhorn and Bad Bentheim in order to prevent potential hazards to the locals population. The main purpose of the project was to provide information on underground mechanisms as far as possible in order to develop long-term safety strategies for freshwater supply in the region. (orig.)
The program introduced here for determining and describing the multi-axial creep of pipes is based, on the one hand, on the results of the nuclear process heat prototype plant material program and, on the other hand, on the possible load conditions which arise for evaluating accidents or extreme working situations. The basis of a theoretical description of multi-axial creep is the invariant theory in which both the von Mises configuration change hypothesis and the Norton creep law are included. Combined tension and torsion are also considered in detail, the superimposition of cyclic stresses in the tensile threshold area is discussed and cases of partial relaxation are explained. Experimental results for the discussed loads are introduced, which have led to satisfactory agreement between theory and experiment. (orig./MM).
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. ...
Apart from presenting the marginal legal conditions the research program contains a brief description of current pollution abatement measures, representative heating systems and individually suitable pollution abatement technologies and an account of the determination of the concentration of major pollutants. The comparative evaluation of heating systems assesses their environmental effects, i.e. air pollution caused by heating systems. The determination of the costs of available heat is followed by an overall evaluation of the results obtained with special regard to the costs involved by pollution abatement measures.
Purpose: Evaluation of the diagnostic efficacy and cost-benefit of contrast enhanced CT (CT) and MRI pre- and post-SPIO-particles in focal hepatic disease with consideration of therapeutic outcome. Results: In 34/52 (65.4%) of the cases the correct diagnosis was primarily stated by CT (sensitivity [se.] 85.2%, specificity [sp.] 44.0%). In additional 10/52 of the cases unenhanced MRI (se. 91.4%, sp. 75.0%) enabled correct diagnoses, and in another 6 cases the diagnosis was established only by SPIO-MRI (se. 100%, sp. 86.7%). Considering the possible therapeutic recommendation arising from each modality, CT would have induced needless therapy costs of 191,042 DM, unenhanced MRI of 171,035 DM, and SPIO-MRI of 7,311 DM. In comparison to the real therapy costs of 221,873 DM, this would have corresponded to an unnecessary increase of therapy costs of 86.1%, 77.1%, and 3.3%, respectively. In two cases (91 hemangioma, 1 regenerative nodule) all modalities failed, causing unnecessary surgery in ...
This final report for the Swiss Federal Office of Energy (SFOE) presents the results of studies made on the regulation of the growth of Legionella Pneumophila bacteria in biofilms and amoebae. In a first project, the formation of biofilms by Legionella Pneumophila bacteria was analysed in static and dynamic systems using a complex growth medium. Under static and dynamic clinical and environmental conditions, the adherence of the biofilms on polystyrene tissue was studied. This was also examined under dynamic flow conditions. In a second part of the project, the regulation of growth of Legionella Pneumophila in amoebae was examined in that changes were made to the genome of the bacteria. The importance of the work for the de-activation of Legionella Pneumophila bacteria in biofilms is noted in the conclusions of the report.
Main driver of the operation costs of agricultural biogas plants are substrate costs. The assessment of the biogas potential of different crops is carried out after ensiling and related to the DM content of the silage. This is insufficient for practical economic calculation due to prior dry mass losses during ensiling and aerobic deterioration. By the use of balancing trials process related dry mass losses can be estimated. In dependence of the deterioration time methane losses of 7,2 - 25,9% were evaluated. The methane losses match with the dry mass losses calculated according to Honig. (orig.)
Smooth and notched specimens of the bearing steel 100Cr6 (SAE 52100) in a bainitic condition were used to determine the S-N curves under tensile, torsional and combined in- and out-of-phase loading. In the area of high-cycle fatigue, crack initiation was most likely caused by inclusions like Titanium Carbon nitrides or Aluminium Oxides. A micro mechanical model for the crack initiation by inclusions was developed. Another model was developed to describe the influence of these inclusions on the lifetime. A weakest-link model, using the statistical distribution of inclusions and surface flaws, was used to describe the endurance limit. (orig.)
Environmental compatibility is nowadays a very important part in the case of planing, construction, operation and maintainance of cable systems. A lot of laws and orders have to be observed. Some new aspects concerning the removal of oil filled cables and the consideration of electromagnetic fields even for cabels will be presented. (orig.) [Deutsch] Der Umweltschutz ist heute unverzichtbarer Bestandteil der Planung, Bau, Betrieb und Instandhaltung von Kabelanlagen. Zahlreiche Gesetze und Verordnungen sind hierbei zu beachten. Der Verfasser stellt einige Neuerungen im Zusammenhang mit dem Ausbau und Oelkabeln vor und erlaeutert die auch bei Kabeln zu beruecksichtigenden elektromagnetischen Felder. (orig.)
The early diagnosis of such disorders is of major importance because, in most cases, severe consequences can only be averted by early treatment. The value of magnetic resonance imaging (MRI) in many orthopaedic and traumatological conditions is generally accepted. The value of MRI in this particular field is illustrated by typical case reports on common clinical problems [Deutsch] Der Fruehdiagnose von Erkrankungen des Kindes- und Jugendalters kommt grosse Bedeutung zu, da oftmals nur durch eine daraus resultierende Fruehbehandlung schwerwiegende Folgen vermieden werden koennen. Die Kernspintomographie (Magnetresonanztomographie=MRT) ist in zahlreichen orthopaedischen-traumatologischen Fragestellungen bereits etabliert. An ausgewaehlten Fallbeispielen haeufiger klinischer Problemstellungen soll in der vorliegenden Arbeit der Stellenwert der MRT dargestellt werden. (orig.)
An adaptive contingency selection process is set up which produces outage lists in order to guarantee on-line network security control. The quality index system used so far did not detect and reveal all critical variables due to observation problems in the mapping of two functions. The new process uses the results of the outage simulation computing of the system status just past for the drawing up of an up-to-date outage list. A linear correcting function transform the G{sub 2}-values of the standard quality index method - which still incorporate the observation problem effect - into improved values G. Studies which use data from realstic high-voltage networks prove that the detection of critical variables is far superior to ordinary methods. (orig.).
Purpose: With intracranial tumors a flat, contrast-enhancing, probably dural structure adjacent to the tumor can occasionally be observed on gadolinium-DTPA enhanced MR images. Therefore we have attempted to evaluate a tumor infiltration of this enthancement on MRI. Material and Methods: This study included 50 patients. 19 patients had a dural thickening at the tumor base (13 meningiomas and 6 metastases), while 31 patients did not (12 meningiomas and 19 metastases). Studies included plane T{sub 2}-weighted spin echo (SE) images as well as T{sub 1}-weighted axial, coronal, or sagittal plains with and without contrast agent. Histopathological examinations, were done on the tumor base adjacent to the dura mater. Results: 7 of 12 meningiomas showed a meningeal thickening on MRI with histopathologically proven tumor infiltration as did also 5 of 6 metastases. But 3 of 12 meningiomas and 15 of 19 metastases without dural thickening at the tumor base also showed tumor invasion into the dura ...
We consider dimensional reduction techniques for the Liouville-von Neumann equation for the evaluation of the expectation values in a mixed quantum system. In applications such as nuclear spin dynamics the main goal for simulations is being able to simulate a system with as many spins as possible, for this reason it is very important to have an efficient method that scales well with respect to particle numbers. We describe several existing methods that have appeared in the literature, pointing out their limitations particularly in the setting of large systems. We introduce a method for direct computation of expectations via Chebyshev polynomials (DEC) based on evaluation of a trace formula combined with expansion in modified Chebyshev polynomials. This reduction is highly efficient and does not destroy any information. We demonstrate the practical application of the scheme for a nuclear spin system and compare with several alternatives, focusing on the performance ...
Summary A prospective and randomized trial design is of utmost interest when it comes to evaluating new developments in the management of cardiovascular medicine. By defining the primary end point and a profound related statistic new therapeutic options can be tested with an adequate number of patients. The course of the trial is supervised by a Clinical Events Committee and a Data and Safety Monitoring Board. Registries are promising tools for describing how the results of clinical trials are translated into daily practice. Their drawbacks include lack of control of the clinical endpoints and their uniform definition and lack of a control group. There are numerous examples from cardiology of the limited usefulness of data obtained from registry studies with their often unexpected results ...
Fur die Trennung binarer Gemische wird zunehmend das Simulated Moving Bed (SMB)-Verfahren verwendet. Fur einen storungsfreien Betrieb mussen die Volumenstrome sowie die Umschaltzeit exakt eingestellt werden. In diesem Beitrag wird mit Hilfe des Coherence-Konzepts eine Methode aufgezeigt, mit der sich die Stellgroen fur einen dispersionsfreien SMB-Prozess bestimmen lassen. Fur Langmuir- und Anti-Langmuir-Isotherme konnen einfache explizite Gleichungen bei vollstandiger Trennung angegeben werden. Das Grundprinzip dieser Methode lasst sich auch auf andere Isotherme sowie fur die unvollstandige Trennung ubertragen.
ZusammenfassungDie Botulinumtoxinbehandlung ist eine etablierte Methode in der Behandlung von spasmodischen Dysphonien. Prinzipiell kann eine Behandlung transkutan zervikal, transoral mit einer gebogenen Spritze unter visueller Kontrolle w?hrend der Laryngoskopie sowie mittels flexibler Endoskope bzw. Videoendoskope mit Arbeitskanal erfolgen. Insbesondere die transkutane Injektion unter Larynx-EMG-Kontrolle (LEMG) ist ein verh?ltnism??ig einfaches Verfahren. Aufgrund der visuellen Kontrolle bei transoral oder flexibel transnasal verabreichtem Botulinumtoxin scheint eine bessere Wirksamkeit zu bestehen. Aus verschiedenen Gr?nden kann dieses Verfahren aber nicht bei allen Patienten verwendet werden. Wir berichten ?ber unsere Erfahrungen mit den verschiedenen Techniken und unsere Erw?gungen i...
This final report for the Swiss Federal Office of Energy (SFOE) examines a project that aimed to define standard solutions for use in buildings built to meet Minergie low energy consumption standards. These standard solutions are to provide a way of meeting Minergie standards in an easy way and thus further the use of the standard and also assure quality at the same time. The report describes how the solutions were developed on the basis of a selection of existing Minergie buildings. For various combinations of heating systems - wood, wood/solar, heat pumps (brine-water and air-water), gas/solar and oil/solar - the appropriate U-values for various building elements are listed. The resulting Minergie forms and guides are listed.
The plastic deformation behavior of formed CICC for the superconducting Tokamac fusion device was examined and appropriate manufacturing information was provided. A relation between travel of the bending roller and spring back displacement was obtained via virtual manufacturing. The radius of CICC after forming was expressed as a function of the bend-roll travel. The maximum von Mises stress after spring back was also monitored for the SAGBO prediction. Next, the variation of the CICC cross-sectional area was examined during the first turn and during conduit bending with the largest curvature. Finally, the coil radius was measured and compared with the data generated from the virtual manufacturing. The measured data showed similar pattern as predicted one. Using the mapping function found to match with the real data, the data from the virtual manufacturing may facilitate accurate manufacturing.
The plastic deformation behavior of formed CICC for the superconducting Tokamac fusion device was examined and appropriate manufacturing information was provided. A relation between travel of the bending roller and spring back displacement was obtained via virtual manufacturing. The radius of CICC after forming was expressed as a function of the bend-roll travel. The maximum von Mises stress after spring back was also monitored for the SAGBO prediction. Next, the variation of the CICC cross-sectional area was examined during the first turn and during conduit bending with the largest curvature. Finally, the coil radius was measured and compared with the data generated from the virtual manufacturing. The measured data showed similar pattern as predicted one. Using the mapping function found to match with the real data, the data from the virtual manufacturing may facilitate accurate manufacturing.
In certain regions of the sea floor, water and methane from organic depositions have turned into a burnable form of ice, i.e. methane hydrates which contain more stored energy than all fossil fuel reserves. If they should desintegrate as a result of global heating, methane will be released and will contribute to further global heating. [Deutsch] Im Boden bestimmter Meeresregionen haben sich Wasser und Methan aus organischen Ablagerungen zu einer brennbaren Form von Eis vereinigt. Diese Methanhydrate speichern mehr Energie als alle fossilen Brennstoffvorraete. Wenn sie sich bei einer globalen Erwaermung zersetzen, koennte das entweichende Methan als Treibhausgas die Erde noch mehr aufheizen. (orig.)
This article discusses the use of five-core cables to provide utility customers with the best possible prerequisites for trouble-free operation of electrical installations and equipment. The TN-S system in buildings and the new TN-S-five-core house-connection cable for connections between the mains distribution point and buildings is introduced. The long-term target of providing TN-S-systems in power distribution even as far as the local transformer is also discussed. The advantages of the system are discussed and various configurations for different types of supply are described.
This final report for the Swiss Federal Office of Energy (SFOE) reports on work done in the area of gasification of biomass. The use of dung, manure and sewage sludge as sources of energy is described and discussed. Hydrothermal gasification is proposed as an alternative to conventional gas-phase processes. The aim of the project in this respect is discussed. Here, a catalytic process that demonstrates the gasification of wet biomass to synthetic natural gas (SNG) in a continuously operating plant on a laboratory scale is being looked at. Difficulties encountered in preliminary tests are discussed. Long-term catalyst stability and the installations for the demonstration of the process are discussed, and gasification tests with ethanol are commented on.
Iron nickel chromium manganese silicon and iron chromium nickel manganese silicon molybdenum niobium alloys have a so-called duplex structure in a wide concentration range. This causes an excellent resistance to wear superior in the case of adhesive stress with optimized concentrations of manganese, silicon, molybdenum and niobium. The materials can be used for welded armouring structures wherever cobalt and boron-containing alloy systems are not permissible, e.g. in nuclear science. Within the framework of pre-investigations for manufacturing of filling wire electrodes, cast test pieces were set up with duplex structure, and their wear behavior was examined. (orig.).
This study is concerned to the perforation phenomena of the oblique dual-plate by projectile. Experiment and simulation related to that was carried out. the variables considered in this phenomena include the electrolytic zinc coated steel sheet and carbon steel rod. In the former, the confirmation and projectile velocity possible phenomena of real phenomena is done, the latter, the effect of parameter such as time-step and grid space length is analyzed by using the three-dimensional Lagrangian explicit time-integration finite element code, HEMP. This code use the eight node hexahedral elements and in this study, Von-Mises Criteria is used as the strength model, Mie-Gruneisen is as the Equation of State. The simulation was performed by contrast with the experiment. Through the calibration of the parameter of Lagrangian code, reasonable result was approached.
There are alarming scenarios that state that global heating caused by anthropogenic gaseous emissions will melt the ice caps of Greenland and the Antarctic. This would cause flooding of coastal regions on a global scale. The floods are expected already in the next century, but there are no realistic assessments of the extent of the danger. (orig.) [Deutsch] Alarmierenden Szenarien zufolge koennten durch eine globale Erwaermung, die der Mensch mit dem Ausstoss von Treibhausgasen in die Atmosphaere verursacht, die Eiskappen auf der Antarktis und Groenland abschmelzen. Schon im kommenden Jahrhundert wuerden dadurch weite kuestennahe Gebiete ueberflutet. Noch aber laesst sich schwer abschaetzen, wie real die Gefahr ist. (orig.)