Elektrotechnik und Medientechnik
Techniques for the Production of High Quality Lenses by the Utilisation of a Knowledge Based System
The rapid increase in the employment of optics-based technologies in modern life has spurred the search for lenses that exhibit exceptionally high optical accuracies, and yet are simple and cheap to manufacture. Currently, most complex lenses are based on multiple lens elements of spherical form, and it is common for a number of these spherical elements to be combined into a single optical objective. However, a characteristic of spherical lenses, spherical aberration, prevents the spherical lens from achieving perfect refraction and leads to distortion of the image at the focus point. It is for this reason that multiple spherical elements are generally necessary. Aspherical, sometimes referred to as free-form, lenses enable the incorporation of compensation for spherical aberration. Such aspherical lenses may exhibit a perfect focus, will be lighter in weight and will be smaller in size than equivalent multi-spherical objectives. However, the production of asphericallenses is complex, a consequence of their intricate shape. Research was undertaken to analyse the methods for producing lenses. In particular magnetorheological finishing was studied extensively. This process utilises a fluid that is stiffened under the influence of a magnetic fluid as the polishing agent. It is an extremely capable and adaptable process, but yet is subject to many complex factors that influence the manner in which it may be applied to the optical finishing process. The magnetorheological finishing process was investigated, and procedures for synthesising the machine characteristic, referred to as the influence function, were proposed. Employment of the technique that was developed will reduce the quantity of optical material used for testing and machine characterisation, so reducing scrap, while saving the manufacturing time that must normally be devoted to the characterisation operation. In addition, a knowledge-based system was established, which may provide guidance and direction as to the most appropriate lens-processing conditions to adopt. The results of this work have generic applications, in diverse processes, wherever surface preparation and surface finishing are required - See more at: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.572873#sthash.SQKYg44i.dpuf
MobilEuropan Campus Rottal-Inn
Usability in der Webagentur: Usability als Teil der Qualitätssicherung in der Webagentur – Entwurf eines Prozessmodells unter Berücksichtigung von Praxisbeispielen
Maschinenbau und Mechatronik
Hocheffiziente Abscheidung von Stäuben und Geruchstoffen mittels eines neuen Bio-Elektrischen Geruchs- Abscheiders (BEGA)
Environmental economic aspects of river basins and their catchment
Identification and quantification of flood related land use externalities
This thesis investigates a common problem of land use impacts on flood damage costs on a catchment scale. It does this through a particular case study, to quantify the technical upstream-downstream dependencies and highlights the externalities through hydroeconomic analysis of flood damages and mitigation costs. The substantive content of the project is cross disciplinary. Peak and volume of river flows are functions of the catchment surface characteristics. This means that any impacts to the run-off regime (for example surface sealing or river training) could affect people and land users in the lower catchment. Thus, upstream activities can cause higher flood peaks, and also entail higher damages downstream. These damages are either borne by the affected parties or they are mitigated by state financed flood defence works or offset with financial compensation. These costs are usually not included in the economic considerations of the upstream land user who is partially causing them. In economic terms, these effects are referred to as unidirectional externalities. This means that a producer can export parts of his production costs to third parties and these are not included in the price of the product. The Herzogbach is a small tributary of the Danube River in Lower Bavaria. It is located in a rural area, dominated by intensive farming practices. Two villages (Bachling and Buchhofen) in the headwaters and middle section of the catchment and one city (Osterhofen) in the lower catchment were analysed to determine the impact of upstream land use practices on the flood situation. A combination of hydrological and hydraulic modelling provided the core data to allow the interpretation of economic data, using methods of cost damage estimation. A hydrological model of the catchment provided hydrograph simulations based on (a) a regionalisation approach, (b) hydrologic flood routing and (c) hydrologic reservoir routing. A two dimensional stream flow model was then used to convert the hydrographs into flood levels, to simulate the run-off in settled areas and determine the flood affected areas, flood levels and flow velocities. Estimates for flood damages or mitigation costs resulting from different hydrological scenarios were compared. The scenarios are based on different land uses and allow economic externalities to be estimated. It was found that intensive farming and river training increase the peaks, shape and volume of flood waves in comparison to extensive land use, grassland or forest. In the study area, especially river training reduced the detention effect of the river bed and the natural flood plain. These significant changes to the natural run-off regime directly affect land use in the lower catchment through flood damages and increased flood risk, and by reducing the effectiveness of planned or existing flood protection works. The thesis concludes with linked technical and economic findings which indicate a rich potential new area for research - “hydroeconomics”. The published literature shows few people have worked in this cross disciplinary area. The technical finding is that changes to land use, especially in agriculture, can increase the flood damages in downstream settlements or increase the cost of flood mitigation works significantly. From an economic point of view, this is a unidirectional externality which should be considered in catchment and flood management. Possible solutions could include the control of land use and instruments such as separate waste water fees for rainwater and sewage or run-off certificates.
Übertragbarkeit von Methoden und Verfahren in der objektorientierten Bildanalyse - das Beispiel informelle Siedlungen
NachhaltigAngewandte Naturwissenschaften und WirtschaftsingenieurwesenEuropan Campus Rottal-Inn
Supraleitende YBa2Cu3O7-δδ-Schichten auf metallischen Bändern
For the use of high-temperature superconducting materials in energy technology flexiblewires or tapes are needed. Up to now two different routes for their fabrication do exist.Primary there is the powder in tube process, which uses polycrystalline BSCCO powder in asilver tube. Secondary there are the coated conductor concepts, which use a metallic tape as asubstrate for the deposition of buffer and superconducting layers. In order to achieve highcritical current densities biaxially textured layers of the superconductor YBCO are necessary.As a consequence either the substrates (RABiTS: rolling assisted biaxially textured substratesapproach) or the deposited buffers (IBAD: ion beam assisted deposition approach) have to betextured. In this thesis the RABiTS approach was used to produce short samples ofsuperconducting tapes.One of the most important aspects of the RABiTS technique is the deposition of buffer layers,which serve as a chemical barrier between the ferromagnetic Nickel substrate and match thestructural properties of the substrate tape and the YBCO layer. In order to deposit high qualityYBCO films on textured Nickel substrates highly (100) textured and crack free buffer layersare needed. Only few materials such as CeO2 and Yttria-stabilised Zirconia (YSZ) are suitedfor the use as a buffer layer. In this thesis several deposition techniques such as rf sputtering,thermal reactive evaporation and electron beam evaporation were developed and tested for thedeposition of CeO2 and YSZ. The buffer layers were characterised by XRD, SEM and opticalmicroscopy. The growth behaviour of CeO2 on Nickel was studied in detail to ensure (100)oriented growth on the cube textured Nickel substrate. Growth conditions for the reproducibledeposition of (100) oriented buffer layers could be found.YBCO films were deposited by dc-sputtering on the buffer layers and the resultingsuperconducting properties were measured by inductive characterisation and transport currentmeasurements. The cracking of the buffer layers during the highly oxidising conditions of theYBCO deposition process turned out to be the main obstacle to achieving goodsuperconducting properties. After optimisation critical current densities up to 0.6 MA/cm2(77 K, 0 T) and critical temperatures of 91 K with transition widths of 3 K could be obtainedin 400 nm thick YBCO films on exclusively evaporated CeO2/YSZ/CeO2 buffer architectures.These layers still showed cracks after the YBCO deposition, which seemed to be the cause forthe low critical current densities. Buffer architectures with evaporated CeO2 followed bysputtering of YSZ and CeO2 remained crack free after the YBCO deposition. Critical currentdensities between 1.5 and 2.6 MA/cm2 (77 K, 0 T) in 400 nm thick films could be achievedreproducibly. The transition temperatures were measured to be between 91 and 92 K withtransition widths of 1.5 K.
Hochschulleitung und -einrichtungen
Die deliktische Haftung des GmbH-Geschäftsführers für fehlerhafte Buchführung
Ursache für den Vermögensverfall einer GmbH ist oft eine unzulängliche und fehlerhafte Buchführung. Verantwortlich ist der Geschäftsführer der GmbH. Ob geschädigte Gesellschaftsgläubiger den Geschäftsführer deswegen persönlich in Anspruch nehmen können, untersucht der Verfasser des folgenden Beitrags.
Die Anwendung fernerkundlicher Daten und Methoden im Geomarketing, untersucht am Beispiel einer KFA-1000-Aufnahme von München
Bauingenieurwesen und Umwelttechnik
Zur Berechnung des ebenen Spannungs- und Verzerrungszustandes der Schubzone von schubbewehrten Stegen profilierter Stahlbeton- und Spannbetonträger im Grenzzustand der Schubtragfähigkeit
Mensch- Mikrocomputer Kommunikationssystem - Management Expertensystem in der chemischen Industrie auf der Basis eines universellen Daten- und Prozeduralmodells auf einem Mikrocomputerverbundsystem