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...
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 ...
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 von 1310-1470 PJ/a. Ob dieses ...
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 zur ...
This richly illustrated toolbook and atlas contains information on all aspects of nmr diagnostic imaging of benign or malignant neoplasms of female and male mammary glands. It offers pinpointed guidance and insight for vocational training and continuing training of radiology assistants, students and medical radiologists. (orig./AJ) [German] Die MRT als hochaufloesendes und schaedigungsfreies Diagnostikum gewinnt gerade in der emotional stark besetzten Mammadiagnostik zunehmend an Bedeutung. Dennoch beherrschen nur wenige Zentren im deutschsprachigen Raum diese Technik, die - eine hohe Reproduzierbarkeit bei fehlender Belastung fuer die Patientin bietet, - invasive Karzinome bereits ab einer Groesse von 5 mm mit hoher Zuverlaessigkeit ausschliessen kann und - gerade bei widerspruechlichen Befunden zwischen klinischer Untersuchung, Roentgenmammographie und perkutaner Biopsie eine wesentliche Entscheidungshilfe bieten kann. Aus einem der ...
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 ...
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 ...
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 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)
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.)
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.)
Mechanical ventilation in private homes was for many years a stepchild of air conditioning engineers. A decisive impulse for change came in January 1995 with the enactment of the new Thermal Insulation Ordinance which for the first time allows house owners to exceed the usual admissible annual heating requirement by a certain amount on the condition that they equip the house with mechanical ventilation systems. (orig.) [Deutsch] Ueber lange Jahre war die mechanische Wohnungslueftung ein Stiefkind der Raumlufttechnik. Einen entscheidenden Impuls gab erst die seit Januar 1995 gueltige Waermeschutzverordnung, die erstmals zulaesst, dass ein gewisses Quantum des Jahres-Heizwaermebedarfs durch den Einbau mechanischer Wohnungslueftungen kompensiert werden kann. (orig.)
Utilisation of geothermal energy may soon become an important factor in power supply in Germany. The contribution discusses the utilisation of hydrothermal low-pressure systems, the geological boundary conditions, the technical design of the thermal water cycle, and the current status of the hot dry rock technology. [German] Die Nutzung der Energie ausd Erdwaerme kann in naher Zukunft eine wichtige Rolle in der Energieversorgung Deutschlands spielen. Der vorliegende Artikel gibt einen Ueberblick ueber die Nutzung hydrothermaler Niederdrucksysteme, die geologischen Rahmenbedingungen, den technischen Aufbau des Thermalwasserkreislaufes sowie zum aktuellen Stand des Hot Dry Rock Verfahrens.
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.)
Only two types of 110-kV-cables: Namely XLPE-Cables and External-Gas-Pressure-Cables will be reinstalled in the Federal Republic of Germany. XLPE-Cables have been already developed for higher voltages. An idea how the external-gas-pressure-cable could be made fit for higher voltage levels will be given in this paper. (orig.) [Deutsch] In der Bundesrepublik Deutschland werden in der Zukunft nur noch zwei Kabeltypen der 110-kV-Ebene den Kabelmarkt beherrschen, naemlich: VPE-Kabel und Gasaussendruck-Kabel. Waehrend VPE-Kabel auch fuer hoehere Spannungsebenen bereits entwickelt worden sind, wird im folgenden vorgeschlagen, wie auch das Prinzip der Gasaussendruck-Kabel zu hoeheren Spannungen hin erweitert werden kann. (orig.)
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.)
The aim of the study was to establish by means of a measuring programme how much energy for space heating can be saved by the installed hybrid system. Further, experience with the systems was to be gathered under practical use conditions. As user behaviour can influence space heating energy consumption to an extent having several times the effect of the contribution of the hybrid system, a fact that is also reported in literature, it is not sufficient to measure only space heating energy consumption. So, a unit in one of the terraced houses was scrupulously measured. In the three other terraced houses, only space heating energy consumption was measured.- This final report contains not only a description of the concepts of the buildings and hybrid system but also the energy consumptions measured, and detailed analyses of the budgets. (orig./AKF) [Deutsch] Mit Hilfe eines Messprogrammes sollte ermittelt werden, welche Heizwaermeeinsparung durch das installierte Hybridsystem praktisch ...
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 Acrolein als einfachster ...
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 ...
Magnetic resonance imaging (MRI) in stroke makes it possible to visualize the initial infarct in cases of acute cerebral ischemia. Perfusion MRI serves to determine which tissues are additionally at risk of infarction due to persistent hypoperfusion. MRI also allows those examiners with limited experience to reliably confirm an infarct. The most important differential diagnosis of cerebral ischemia, intracerebral hemorrhage, can likewise be recognized with certainty using MRI. Although diffusion and perfusion MRI only demonstrate the pathophysiology of cerebral ischemia approximately, the method is suited for identifying those patients who would profit from reperfusion therapy. Whether MRI is also appropriate as an aid to reaching a prognosis on the risk of secondary hemorrhage has not yet been resolved. (orig.) [German] Die Schlaganfall-MRT ermoeglicht es, bei akuter zerebraler Ischaemie den bereits initial entstandenen Infarkt darzustellen. Mittels Perfusions-MRT ...
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 von ...
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. ...
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 ...
TENSOMAX enables on-line monitoring of the thermal stress of the shaft to be performed in steam turbines, for which the TURBOMAX probe cannot be installed near the critical area of the shaft. TENSOMAX provides an alternative to the TURBOMAX with a slightly reduced accuracy of the simulation of the temperature distribution in the shaft. The high value placed on the operational performance of TENSOMAX remains, viz. that even with older turbines, and particularly in the case of turbines rehabilitated with a new shaft, careful and transparent operation is assured. (orig.) [German] Die Einrichtung TENSOMAX ermoeglicht eine Ueberwachung der thermischen Beanspruchung der Welle bei Dampfturbinen, bei denen die TURBOMAX-Sonde in der Turbine nahe der kritischen Stelle der Welle nicht einsetzbar ist. Daher stellt der TENSOMAX unter Beruecksichtigung minimaler Ungenauigkeit aufgrund der Nachbildung der Waermeuebergangszahl eine vorteilhafte Alternative zum TURBOMAX dar. Der betriebsmaessig ...
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 HTSL-Komponenten eingesetzt werden. (orig.)
The following parameters merit examination in determining the viability of process combinations: conceptual and technical soundness, environmental acceptability, energy balance, flexibility, costs, economic risk potential. The present contribution on this subject is not intended to take the place of or cover the scope of single-case studies. In practice, viability studies on process combinations have to deal with concrete plans involving precisely defined material flow balances, emissions, costs etc. The present paper therefore only presents the basic principles of this type of study. [Deutsch] Folgende Randbedingungen fuer sinnvolle Verfahrenskombinationen sind zu untersuchen: - konzeptionelle und technische Stimmigkeit, - Umweltvertraeglichkeit, - energetische Bilanz, - Flexibilitaet, - Kosten, - oekonomisches Risikopotential. Nun kann dieser Beitrag zum Thema keine Einzelfallbetrachtung ersetzen bzw. abdecken. Im Rahmen einer echten Pruefung auf `Sinnhaftigkeit` ...
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 sich, dass dem Stand ...
Despite successful reduction of the general lead exposure, this heavy metal is still a matter of public concern due to the fact that associations with intellectual impairment or delayed puberty are found to correlate with very low lead blood concentrations. Lead in tap water is still an important contribution to lead exposure which may cause health risk for infants. Therefore, lead pipes should be completely sanitated by exchange against pipes made from more healthy materials. (orig.) [German] Trotz erfolgreicher Reduktion der allgemeinen Belastung ist Blei auch heute noch umweltmedizinisch relevant, weil es moeglicherweise bei niedrigeren als bisher angenommenen Belastungen gesundheitlich nachteilige Wirkungen, insbesondere waehrend der fruehkindlichen Entwicklung des Nervensystems, ausloest. Insbesondere Blei aus bleiernen Trinkwasserleitungen ist eine Belastung, die fuer Saeuglinge und Kleinkinder nach wie vor ein gesundheitliches Risiko darstellen kann. Solche ...
The harnessing and enhanced use of renewable energy today is a matter of lively debate and much concern. Amazingly, hydro power is either rarely considered in these discussions or viewed in a negative light. But hydro power continues to be the most important source of renewable energy, and its use potential is considerable and should be taken into account when, for instance, agreeing on or implementing carbon dioxide reduction targets. Small hydro power stations are an effective means of harnessing existing energy potentials. (orig.) [Deutsch] Ueber die Nutzung und den Ausbau regenerativer Energien wird heutzutage lebhaft diskutiert und gerungen. Es mag erstaunen, dass in diesen Diskussionen die Wasserkraft kaum Beachtung findet oder in einem schlechten Licht gesehen wird. Dabei ist die Wasserkraft nach wie vor bei weitem die wichtigsten Quelle regenerativer Energie, und sie besitzt ein beachtliches Ausbaupotential, das man wenigstens ins Kalkuel ziehen sollte, wenn es etwa darum geht, ...
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 Wichtigkeit der ...
Endoluminal vascular prostheses that can be implanted by percutaneous routes represent the most recent development in vascular interventional radiology. Various commercially available types of prosthesis are presented and the construction principles and applications are described. At present secure indications for the implantation of endoluminal prostheses are limited to the elimination of aneurysms and arteriovenous fistulae of the large vessels near the trunk in sections that do not cross a joint. The wide use in peripheral occlusive diseases cannot yet be recommended because confirmed data are not available. (orig.) [German] Endoluminale Gefaessprothesen, die perkutan implantierbar sind, stellen die juengste Entwicklung in der vaskulaeren interventionellen Radiologie dar. Verschiedene kommerziell erhaeltliche Prothesentypen werden vorgestellt, ihr Konstruktionsprinzip und ihre Applikation erlaeutert. Die gesicherten Indikationen zur endoluminalen Prothesenimplantation beschraenken ...
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 oder seriennahen Ladern ...
The current discussion on worldwide climate change suggests that the current situation is unusual or extreme, and that climate changes never - or hardly ever - occurred in the centuries before. The author discusses whether this is really the case, and whether air pollution abatement measures can really help. His answers are based on the findings of palaeoclimatology. [German] Verfolgt man die Diskussion um den derzeitigen Klimawandel, so gewinnt man den Eindruck, Aussergewoehnliches und Extremes wuerde geschehen, und man bekommt zudem ueber Beratungsgremien und Medien vermittelt, dass sich in den Jahrhunderten vor dem heutigen Klimawandel das Klima nicht oder nur wenig geaendert hat. Es wird auch der Eindruck erweckt, man koenne das Klima stabilisieren und durch Emissionsminderungsmassnahmen das Klima schuetzen. Ist Klimaschutz eine loesbare Herausforderung oder ueberschaetzen wir Menschen unsere Moeglichkeiten? Man kann versuchen, sich an die Beantwortung dieser ...
Pulmonary tumors in children are rare. Nevertheless, there are besides malign primary neoplasms and metastases also some benign tumors that the radiologist should know. The identification of some tumors is difficult, since some of them may mimic pulmonary inflammation. The first diagnostic tool is chest radiography. After that, a CT with contrastmedium should be performed, if possible a multislice-CT (MSCT). Identification of mediastinal structures is best with MRI. (orig.) [German] Tumoren der Lunge sind im Kindesalter selten. Trotzdem finden sich neben den malignen primaeren und sekundaeren Raumforderungen auch im Kindesalter immer wieder benigne Tumoren, die der Radiologe kennen sollte. Eine eindeutige Identifizierung kann schwierig sein, da z. B. entzuendliche Infiltrate vorgetaeuscht werden koennen. Die primaere Untersuchungsmethode ist das konventionelle Thoraxroentgen. Die weitere Diagnostik muss mit der Computertomographie, nach Moeglichkeit mit einem ...
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 ...
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 ...
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 ...
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 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 ...
The aim of this work was the examination of the coarse grain recrystallisation of the {gamma}-free ODS nickel-based alloy PM 1000 depending on the various parameters due to the processing during heat treatment. After isotropic hot compacting (HIP) of the mechanically alloyed powder, one observes a homogeneous sub-microscopic fine grain structure which can coarsen during high temperature heat treatment, due to sufficiently high driving force from the grain boundary energy via abnormal grain growth to 600 times its size. The setting of the elongated high temperature resistant recrystallisation structure is, however, not connected with this. The dependence of the sucess of re-crystallisation on the re-forming parameters (re-forming temperature and degree of re-forming) was shown by a socalled re-forming card. In order to achieve re-crystallisation to a coarse and aligned grain structure, apart from a certain absolute minimum degree of re-forming, the re-forming must occur within a defined ...
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 ...
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 ...
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 ...
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 ...
A whole sequence of the parameters of the combined heat and power system (KWK) is described which enables a comparison between the electricity and heat demand of a consumer and the energy availability through a combined heat and power system. Proceeding from this, a thermodynamic model of a steam and gas process with combined heat and power is introduced which is based on an exergetic balancing of the subsystems of the process. In this way, the varying thermodynamic quality of the energy flows occuring in the process will be taken into consideration so that the results of the model correspond in any case with the second law of thermodynamics. (orig.) [Deutsch] Es wird ein vollstaendiger Satz von Kenngroessen der Kraft-Waerme-Kopplung (KWK) beschrieben, mit dessen Hilfe der Strom- und Waermebedarf eines Verbrauchers mit der Energiebereitstellung durch eine KWK-Anlage verglichen werden kann. Darauf aufbauend wird ein thermodynamisches Modell des GuD-Prozesses mit ...
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 ...
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 einen wichtigen ...
An important opportunity for solving future traffic problems lies in a change of the connection existing between traffic growth and economic development. It could help bring about a cut in traffic intensity. This can be achieved by rationalizing transport processes, i.e. by enhancing the efficiency of traffic via improved organization and infrastructure. Rationalization means that a given traffic effort (distance in kilometres, time, route, energy) can yield a higher transport effect, or a certain transport effect can be attained with less traffic effort. Enhanced productivity permits more transport without more traffic-related and environmental nuisances. (orig.) [Deutsch] Ein wichtiger Weg zur Loesung der kuenftigen Verkehrsprobleme liegt in der Veraenderung des Zusammenhangs der zwischen Verkehrswachstum und Wirtschaftsentwicklung besteht. Damit koennte eine Senkung der Transportintensitaet erreicht werden. Ein Ansatz hierzu bietet die Rationalisierung der Transportprozesse, d.h. ...
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 Veraenderungen im Bereich der hinteren ...
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 ...
Osteonecrosis (ON) of the hip joint remains an unsolved therapeutical problem. Diagnosis of ON of the hip has been improved by the technical progress of imaging modalities and better understanding pathomorphology. Over a long period only plain radiographs have been available. Scintigraphy and computed tomography contributed to differential diagnosis and early detection of bone necrosis. Diagnosis in an early reversible stage is of importance. Understanding of pathophysiology, early diagnosis and therapeutical approach has been significantly improved by MR imaging. Using the ARCO system all imaging modalities and their diagnostic viability are described in the five ARCO stages. At the end a diagnostic algorithm will be proposed. (orig.) [German] Die Osteonekrose des Hueftgelenks (ON) stellt noch immer ein nicht geloestes therapeutisches Problem dar. Die diagnostischen Moeglichkeiten bei der ON wurden in den letzten Jahren durch technische Fortschritte bei den bildgebenden Verfahren und ...
Modern commercial alloys are not suited for future steam turbines of operating temperatures beyond 700 C. {gamma}'-hardened alloys like Waspaloy have good mechanical characteristics but have defects when large batches are melted. {gamma}'/{gamma}''-hardened alloys like Inconel 706, on the other hand, are easy to produce but have insufficient microstructural long-term stability and insufficient creep strength. Mixed crystal solidified alloys like Inconel 617 have excessive yield stress at forging temperatures. Two new alloys were therefore developed. Results so far show that they have good production characteristics but insufficient mechanical characteristics. The reasons for this are currently under investigation. (orig.) [German] Die heutigen kommerziellen Legierungen sind nicht geeignet fuer den Einsatz in zukuenftigen Dampfturbinen mit Betriebstemperaturen oberhalb 700 C. {gamma}'-gehaertete Legierungen wie Waspaloy zeigen zwar gute ...
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 ...
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 zusammengefasst. Bei dynamischer Belastung ist kein ...
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 Temperaturausgleich mit der ...
In order for fuel cells to be successful, a full-scale hydrogen infastructure is required. The HyTra concept is presented here (HYdrogen TRAnsform, Transfer and TRAnsport) involves combined production, storage and supply of hydrogen in a transportable trailer, i.e. it is both a hydrogen production unit and a mobile filling station. The trailer can be transported to the selected site, where it will produce gaseous hydrogen from electricity and water by electrolysis. A compressor pumps the gas into an internal pressure tank and compresses it to filling pressure. Filling takes place by the overflow principle via a flexible high-pressure line with a standardised H{sub 2} filling unit. (orig.) [German] Um die Marktdurchdringung der Brennstoffzellentechnik gewaehrleisten zu koennen, muss eine flaechendeckende Wasserstoffinfrastruktur aufgebaut werden. Das neue HyTra-Konzept (HYdrogen TRAnsform, TRAnsfer and TRAnsport) beruht auf der Kombination von Wasserstoff-Erzeugung, -Speicherung und ...
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 composition of alkaline and neutral boric acid containing evaporator concentrates resulting from the treatment of radioactive waste water in nuclear power plants with WWER reactors is described as well as the processing of these concentrates to a product suitable for final disposal. Tests with mock solutions of these evaporator concentrates have been performed at the laboratory and teststand scale to produce a dry residue by continuous thickening, which can be processed into a highly leach resistant product, suitable for final disposal, by cementation. Ca-compounds must be added to the evaporator concentrates prior to the drying in an rotary thin-film evaporator (RTFE). The tests showed that neutral evaporator concentrates can be dried in a RTFE with addition of small amounts of Ca-compounds. The alkaline evaporator concentrates with high boric acid and total salt load require a multiple amount of Ca-compounds and diluting water to perform the drying process. A brief description of ...
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 von Bauteilen und Tragwerken ...
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 Stickoxid-Bildung jedoch als ...
The article explains why electric and gas utilities in Germany should not forget the domestic customers when deciding their key account management strategies and marketing policy in the competitive electricity and natural gas markets. Competition in the German energy sector has just begun, and so far the industrial customers have been absorbing most of the utilities` attention. The authors show that this is a short-sighted management strategy and present a number of reasons speaking in favour of bulding up structures or preserving the loyalty of domestic cutomers, as this customer group will finally play an important role in the utilities` efforts to keep their competitive edge. (orig./CB) [Deutsch] Wenn heute unter Marketingaspekt ueber Kundenbindung im Energiemarkt gesprochen wird, dann wird haeufig zuerst oder sogar ausschliesslich ueber die umsatzstarken Geschaeftskunden nachgedacht. Der Wettbewerb, vor allem im Bereich der Grosskunden, kuendigt sich in drastischen Einschnitten in ...
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} ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
Lung cancer staging according to the TNM system is based on morphological assessment of the primary cancer, lymph nodes and metastases. All aspects of this important oncological classification are measurable with MRI. Pulmonary nodules can be detected at the clinically relevant size of 4-5 mm in diameter. The extent of mediastinal, hilar and supraclavicular lymph node affection can be assessed at the same time. The predominant metastatic spread to the adrenal glands and spine can be detected in coronal orientation during dedicated MRI of the lungs. Search focused whole body MRI completes the staging. Various additional MR imaging techniques provide further functional and clinically relevant information during a single examination. In the oncological context the most important techniques are imaging of perfusion and tumor motion. Functional MRI of the lungs complements the pure staging and improves surgical approaches and radiotherapy planning. (orig.) [German] Das Staging des ...
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 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 ...
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 ...
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 ...
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 aim of this review is to evaluate the role of inflammatory spine disease in patients with chronic back pain. The contribution of imaging modalities for the diagnostic evaluation of back pain is discussed. A systematic literature search based on the classification of seronegative spondyloarthropathies and rheumatoid arthritis was performed. The results of this search and the experiences in a large collective of rheumatological patients are analyzed. The prevalence of rheumatoid arthritis (1-2%) is comparable to that of spondyloarthropathies (1.9%). The etiology of these entities is not fully elucidated. Magnetic resonance imaging is increasingly used for early detection and surveillance of therapy with TNF-{alpha} antagonists. Bone marrow edema, which is only detectable with MRI, represents an early sign of inflammation. Therapy with TNF-{alpha} antagonists is based on clinical and laboratory criteria, and signs of inflammation in MRI. MRI is useful for assessment of the ...
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 ...
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 von ...
We performed a comparative study of digitally and conventionally acquired images in gastrointestinal examinations. Radiation dose and spatial resolution were determined in a water phantom. In 676 examinations with either conventional or digital imaging (system: Diagnost 76, DSI) the number of images and the duration of the fluoroscopy time were compared. 101 examinations with digital as well as conventional documentation were evaluated by using 5 criteria describing the diagnostic performance. The entrance dose of the DSI is 12% to 36% of the film/screen system and the spatial resolution of the DSI may be better than that of a film/screen system with a speed of 200. The fluoroscopy time shows no significant difference between DSI and the film/screen technique. In 2 of 4 examination modes significantly more images were produced by the DSI. With exception of the criterion of edge sharpness, DSI yields a significantly inferior assessment compared with the film/screen technique. (orig./MG) ...
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. ...
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 ...
The comprehensive survey explains the indications and the specific value of the modern tomographic modalities with respect to the various diagnostic issues. Numerous reproductions of CT, MRI, US scans illustrate the aspects discussed. (orig./CB) [German] Bildgebende Verfahren kommen bei der Abklaerung von Erkrankungen des weiblichen Urogenitaltrakts ergaenzend zu der klinischen Untersuchung zur Anwendung. Kongenitale Uterusanomalien werden primaer mit der HSG oder der Laparoskopie diagnostiziert. Zusaetzlich koennen der transvaginale US und in unklaren Faellen die MRT eingesetzt werden. Die Diagnose entzuendlicher Erkrankungen des weiblichen Genitaltrakts erfolgt in der Regel klinisch. Schnittbildverfahren werden bei therapieresistenten, komplizierten Faellen angewendet. Initial werden benigne Neoplasien des Uterus mit dem transvaginalen US abgeklaert. Eine Verdickung des Endometriums ist dabei ein unspezifischer Befund und kann auf eine Hyperplasie, Polypen oder ...
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 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 aim of this study was to evaluate typical magnetic resonance imaging (MRI) findings in early rheumatic diseases manifesting at the soft tissues of the hand using a retrospective analysis. A total of 186 MRI examinations of patients with clinical suspicion of a rheumatic disease were evaluated in a consensus reading by two experienced radiologists. All imaging patterns were assessed with respect to their type and localization. Under blinded and non-blinded conditions diagnoses were correlated with final clinical diagnosis. The most frequent diagnoses were rheumatoid arthritis (RA, 45.7%) and psoriatic arthritis (PsA, 15.6%). The mean correlation between clinical and MRI diagnosis (r) was 0.75 in blinded and 0.853 in non-blinded reading (p <0.001). The following extra-articular imaging patterns were found: synovitis (59.1%), tendovaginitis (91.4%), dactylitis (14.5%), and bone marrow edema (18.3%). Only dactylitis was specific for a particular rheumatic disease (PsA; r=0.934; ...
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 highest concentration of ...
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 ...
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 ...
{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, muessen bei Temperaturen ...
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 ...
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 ...
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 ...
Background. In multiple myeloma 5 different infiltration patterns can be differentiated: 1. Normal appearance of bone marrow, 2. focal involvement, 3. homogeneous diffuse infiltration, 4. combined diffuse and focal infiltration, 5. 'salt-and pepper' pattern with inhomogeneous bone marrow with interposition of fat islands. Methods. For the fast and total acquisition of all patterns a combination of a T1-weighted spin echo sequence and a fat suppression technique is superior. The focal involvement is clearly demonstrated as areas of high signal intensity on e.g. STIR images. Diffuse involvement can be quantified objectively by calculation of the percentage of signal intensity increase after contrast material injection. MRI is superior to X-ray in focal and diffuse involvement. With ultrafast sequences a 'screening' of the whole red bone marrow as for myeloma infiltration is possible. Prognosis. In prognosis studies diffuse infiltration is inferior to ...
The development and improvement of materials plays a key role in energy technology, particularly in power plant technology, because materials are crucial to plant performance and power availability. This becomes particularly clear when one considers that modern power plants generate temperatures of up to 600 C and pressures of up to 230 bar in order to increase process efficiency, conserve resources and reduce CO{sub 2} emissions. Modern heat-resistant materials for power plant technology are customised materials which have been developed to meet the specific requirements of special applications. After the requirement profile has been determined the material is developed or optimised on the basis of previous experiences gained with materials in power plant technology. Basic heat-resistant materials are ferritic materials containing 9 to 12% Cr as well as additions of Mo, V, Nb and W, amongst other elements. Together with the thermomechanical processing, the last-named elements play an ...
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 ...
Purpose: The aim of this study was to evaluate the accuracy of MRI in the measurement of cartilage thickness of the ankle joint in comparison to pathologic and histologic specimens. Patients and methods: The ankle joints of four fresh cadaver feet were imaged on a 1.5 T MR-unit in the coronal plane. Standard T{sub 1}-weighted spin echo (SE) and a T{sub 1}-weighted 3D-GE (FLASH-3D) sequence with fat saturation were applied. Following MR imaging, the talus was explanted and cut parallel to the MR images for macroscopic evaluation and histologic specimens were prepared. MRI measurements of the cartilage thickness of the talus were carried out in two ways: Without and with consideration of a transition zone of intermediate signal intensity between hyperintense cartilage and hypointense cortical bone. The data were compared with the anatomic specimens as the gold standard expressing the difference as a percentage value. On histologic specimens thickness of deep calcified cartilage layer was ...
CT and MRI of acquired abnormalities of the inner ear and cerebello-pontine angle present themselves with very typical findings. The imaging should be adapted to the pathology looked for and either CT or MRI should be used alone or in combination.CT, especially high resolution CT (HRCT), provides an excellent bone contrast, while MRI has a much superior soft tissue contrast. Acute inflammatory changes of the inner ear are solely depicted by contrast-enhanced MRI. HRCT excellently depicts osseous changes of the inner ear and cerebellopontine angle such as chronic ossifying labyrinthitis occurring after acute labyrinthitis, otosclerotic or traumatic changes. Tumorous changes not yielding to bony changes are best delineated by MRI. Posttraumatic hemorrhage and chronic fibrotic changes within the labyrinth are depicted by MRI, only. In conclusion HRCT and MRI are excellent methods to delineate acquired abnormalities of the inner ear and cerebello-pontine angle. HRCT best depicts osseous ...
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 ...
Aim: Today, MRI is an integral part of the presurgical evaluation of patients suffering from partial epilepsy. These patients frequently show focal morphological abnormalities with potential epileptogenic character and surgical resection of these lesions is associated with superior postsurgical outcome as to seizure frequency. Apart from easily detectable defects, such as post-traumatic lesions or cerebral infarction, as wide variety of mainly small abnormalities can be detected using MRI. Methods: In this study, 484 patients suffering from partial epilepsy of temporal or frontal onset were evaluated for the incidence of different lesions in this population. Results: All lesions found were included without evaluating their potential epileptogenicity, which remains to be proven using other procedures (EEG, SPECT, PET, etc.). Involvement of the hippocampal formation was a major finding in temporal lobe epilepsy, which could be detected as sclerosis (T2w-images), atrophy (T2w-TSE or ...
We report for the first time about a micromachined mass flow sensor directly integrated between the double guidance and the needle seat into the body of a Common Rail (CR) injection nozzle. The thermal measurement principle was chosen because gaseous as well as liquid mass flows can be determined fast and precisely. Additionally, with glass-ceramic materials fabricated in a low cost batch process, a high temperature and especially pressure stable substrate can be used. The flow sensitive thin film is realized by an e-beam evaporated 110 nm thick molybdenum (Mo) layer. The latter is electrically characterized by the resistivity of {rho} = 8.2 x 10{sup -7} {omega} m ({+-}2%) at room temperature as well as by the first {alpha}=4.5 x 10{sup -4} K{sup -1} ({+-}5%) and second {beta}=3.0 x 10{sup -6} K{sup -2} ({+-}12%) temperature coefficients of resistance up to 300 C. The static temperature field at and around the thin film sensor on the glass-ceramic substrate is investigated with an IR ...