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Sensitivity of phase detection techniques in aerated chute flows to hydraulic design parameters
(2012)
This paper presents the latest prototype of the integrated emitter turn-off thyristor concept, which potentially ranks among thyristor high-power devices like the gate turn-off thyristor and the integrated gate-commutated thyristor (IGCT). Due to modifications of the external driver stage and mechanical press-pack design optimization, this prototype allows for full device characterization. The turn-off capability was increased to 1600 A with an active silicon area of 823mm2 . This leads to a transient peak power of 672.1kW/cm² . Within this paper, measurements and concept assessment are presented and a comparison to state-of-the-art IGCT devices is provided.
This thesis introduces the Integrated Emitter Turn-Off (IETO) Thyristor as a new high-power device. Known state-of-the-art research activities like the Dual GCT, the ETO thyristor and the ICT were presented and critically reviewed. A comparison with commercialized solutions identifies the pros and cons of each type of device family. Based on this analysis, the IETO structure is proposed, covering most benefits of each device class. In particular the combination of a MOS-assisted turn-off with a thyristor-based device allows a voltage-controlled MOS switching and the low on-state voltage of the thyristors. The following synthesis of an IETO device stands on a three-dimensional field of optimization spanned by electric, mechanical and thermal aspects. From an electric point of view, the lowest possible parasitic inductance and resistance within the commutation path are optimization criteria. The mechanical construction has to withstand the required contact pressure of multiple kilo Newtons. Finally, thermal borders limit the maximum average current of the device. FEM simulations covering these three aspects are performed for several design proposals. An IETO prototype is constructed and measurements on various test benches attest thermal, mechanical and electric performance. A local decoupling of the external driver stage and the presspack housing is presented by a cable connection. This separation enables a thermal and mechanical independence, which is advantageous in terms of vibrations and thermal cycles including increased reliability. The electric pulse performance of the prototype device is a factor of 3.1 above today''s solutions. In single-pulse measurements, a current up to 1600 A was successfully turned off at 115°C with an active silicon area of 823 mm². One reason for this increased turn-off capability is the extremely low-inductive construction. Additional functionality of the IETO thyristor like over-current self-protection and defined short-circuit failure state are successfully verified.
Wir stellen einen USB-Baustein vor, der eine kostengünstige und universelle Möglichkeit schafft , im Unterricht den Themenkreis Messen-Steuern-Regeln zu behandeln. Die Funktionalität orientiert sich am CVK-Interface der Firma Fischertechnik. Im Gegensatz zu kommerziellen Lösungen erlaubt unser Aufbau auch den preiswerten Einsatz in Gruppen- oder Einzelarbeit. Abschließend berichten wir über ein Beispiel aus dem Unterrichtseinsatz.
Disruption experiments targeted at the Bacillus licheniformis degSU operon and GFP-reporter analysis provided evidence for promoter activity immediately upstream of degU. pMutin mediated concomitant introduction of the degU32 allele – known to cause hypersecretion in Bacillus subtilis – resulted in a marked increase in protease activity. Application of 5-fluorouracil based counterselection through establishment of a phosphoribosyltransferase deficient Δupp strain eventually facilitated the marker-free introduction of degU32 leading to further protease enhancement achieving levels as for hypersecreting wild strains in which degU was overexpressed. Surprisingly, deletion of rapG – known to interfere with DegU DNA-binding in B. subtilis – did not enhance protease production neither in the wild type nor in the degU32 strain. The combination of degU32 and Δupp counterselection in the type strain is not only equally effective as in hypersecreting wild strains with respect to protease production but furthermore facilitates genetic strain improvement aiming at biological containment and effectiveness of biotechnological processes.
We present a new approach to the problem of optimal control of solar sails for low-thrust trajectory optimization. The objective was to find the required control torque magnitudes in order to steer a solar sail in interplanetary space. A new steering strategy, controlling the solar sail with generic torques applied about the spacecraft body axes, is integrated into the existing low-thrust trajectory optimization software InTrance. This software combines artificial neural networks and evolutionary algorithms to find steering strategies close to the global optimum without an initial guess. Furthermore, we implement a three rotational degree-of-freedom rigid-body attitude dynamics model to represent the solar sail in space. Two interplanetary transfers to Mars and Neptune are chosen to represent typical future solar sail mission scenarios. The results found with the new steering strategy are compared to the existing reference trajectories without attitude dynamics. The resulting control torques required to accomplish the missions are investigated, as they pose the primary requirements to a real on-board attitude control system.
Risiken des Handels
(2012)
Aufbau von Handelseinheiten
(2012)
Cell-based sensors for the detection of gases have long been underrepresented, due to the cellular requirement of being cultured in a liquid environment. In this work we established a cell-based gas biosensor for the detection of toxic substances in air, by adapting a commercial sensor chip (Bionas®), previously used for the measurement of pollutants in liquids. Cells of the respiratory tract (A549, RPMI 2650, V79), which survive at a gas phase in a natural context, are used as biological receptors. The physiological cell parameters acidification, respiration and morphology are continuously monitored in parallel. Ammonia was used as a highly water-soluble model gas to test the feasibility of the sensor system. Infrared measurements confirmed the sufficiency of the medium draining method. This sensor system provides a basis for many sensor applications such as environmental monitoring, building technology and public security.
In this study we observed courses of micturition symptoms and differentiated degrees of symptoms for each point in time while also considering the impact of bothersomeness. Our data show that not only significantly more patients who have undergone BT suffer from OAB than those who have undergone RP, but also that those affected show significantly higher values for severity of OAB symptoms throughout the whole observation period of 36 months. Our data analysis further shows that variability of OAB symptoms as well as fluctuation of severity of OAB symptoms vary to a significantly higher degree after BT than after RP. Looking only at mean figures at a given point in time clearly underestimates the underlying problem. This fact is not reflected in the literature.
Assessment of RF Safety of Transmit Coils at 7 Tesla by Experimental and Numerical Procedures (490.)
(2012)
Abfallwirtschaft
(2012)
Abfallwirtschaft
(2012)
With a steady increase of regulatory requirements for business processes, automation support of compliance management is a field garnering increasing attention in Information Systems research. Several approaches have been developed to support compliance checking of process models. One major challenge for such approaches is their ability to handle different modeling techniques and compliance rules in order to enable widespread adoption and application. Applying a structured literature search strategy, we reflect and discuss compliance-checking approaches in order to provide an insight into their generalizability and evaluation. The results imply that current approaches mainly focus on special modeling techniques and/or a restricted set of types of compliance rules. Most approaches abstain from real-world evaluation which raises the question of their practical applicability. Referring to the search results, we propose a roadmap for further research in model-based business process compliance checking.
Background
Minor changes in protein structure induced by small organic and inorganic molecules can result in significant metabolic effects. The effects can be even more profound if the molecular players are chemically active and present in the cell in considerable amounts. The aim of our study was to investigate effects of a nitric oxide donor (spermine NONOate), ATP and sodium/potassium environment on the dynamics of thermal unfolding of human hemoglobin (Hb). The effect of these molecules was examined by means of circular dichroism spectrometry (CD) in the temperature range between 25°C and 70°C. The alpha-helical content of buffered hemoglobin samples (0.1 mg/ml) was estimated via ellipticity change measurements at a heating rate of 1°C/min.
Results
Major results were:
1) spermine NONOate persistently decreased the hemoglobin unfolding temperature T u irrespectively of the Na + /K + environment,
2) ATP instead increased the unfolding temperature by 3°C in both sodium-based and potassium-based buffers and
3) mutual effects of ATP and NO were strongly influenced by particular buffer ionic compositions. Moreover, the presence of potassium facilitated a partial unfolding of alpha-helical structures even at room temperature.
Conclusion
The obtained data might shed more light on molecular mechanisms and biophysics involved in the regulation of protein activity by small solutes in the cell.
Dynamik bei Eisenbahnbrücken
(2012)
The esophageal Doppler monitor (EDM) is a minimally-invasive hemodynamic device which evaluates both cardiac output (CO), and fluid status, by estimating stroke volume (SV) and calculating heart rate (HR). The measurement of these parameters is based upon a continuous and accurate approximation of distal thoracic aortic blood flow. Furthermore, the peak velocity (PV) and mean acceleration (MA), of aortic blood flow at this anatomic location, are also determined by the EDM. The purpose of this preliminary report is to examine additional clinical hemodynamic calculations of: compliance (C), kinetic energy (KE), force (F), and afterload (TSVRi). These data were derived using both velocity-based measurements, provided by the EDM, as well as other contemporaneous physiologic parameters. Data were obtained from anesthetized patients undergoing surgery or who were in a critical care unit. A graphical inspection of these measurements is presented and discussed with respect to each patient’s clinical situation. When normalized to each of their initial values, F and KE both consistently demonstrated more discriminative power than either PV or MA. The EDM offers additional applications for hemodynamic monitoring. Further research regarding the accuracy, utility, and limitations of these parameters is therefore indicated.
Two of the main environmental problems of today’s society are the continuously increasing production of organic wastes as well as the increase of carbon dioxide in the atmosphere and the related green house effect. A way to solve these problems is the production of biogas. Biogas is a combustible gas consisting of methane, carbon dioxide and small amounts of other gases and trace elements. Production of biogas through anaerobic digestion of animal manure and slurries as well as of a wide range of digestible organic wastes and agricultural residues, converts these substrates into electricity and heat and offers a natural fertiliser for agriculture. The microbiological process of decomposition of organic matter, in the absence of oxygen takes place in reactors, called digesters. Biogas can be used as a fuel in a gas turbine or burner and can be used in a hybrid solar tower system offering a solution for waste treatment of agricultural and animal residues. A solar tower system consists of a heliostat field, which concentrates direct solar irradiation on an open volumetric central receiver. The receiver heats up ambient air to temperatures of around 700°C. The hot air’s heat energy is transferred to a steam Rankine cycle in a heat recovery steam generator (HRSG). The steam drives a steam turbine, which in turn drives a generator for producing electricity. In order to increase the operational hours of a solar tower power plant, a heat storage system and/ or hybridization may be considered. The advantage of solar-fossil hybrid power plants, compared to solar-only systems, lies in low additional investment costs due to an adaptable solar share and reduced technical and economical risks. On sunny days the hybrid system operates in a solar-only mode with the central receiver and on cloudy days and at night with the gas turbine only. As an alternative to methane gas, environmentally neutral biogas can be used for operating the gas turbine. Hence, the hybrid system is operated to 100% from renewable energy sources
Thin films of poly(ethyleneterephthalate) [PET]were exposed to radiation dose ranging from 10 to 30 kGy by using gamma rays in the range 12.8-177.8 MGy using swift light ions of hydrogen. There was no effect of the radiation dose on the optical behaviour of PET as a result of exposure to radiation dose up to 30 kGy brought about by gamma rays but a significant decrease in the optical band gap values was observed when PET was exposed to swift light ions of hydrogen. The data obtained are discussed in terms of optical studies carried out on PET using swift heavy ions.
Label-free electrical detection of consecutive deoxyribonucleic acid (DNA) hybridization/denaturation by means of an array of individually addressable field-effect-based nanoplate silicon-on-insulator (SOI) capacitors modified with gold nanoparticles (Au-NP) is investigated. The proposed device detects charge changes on Au-NP/DNA hybrids induced by the hybridization or denaturation event. DNA hybridization was performed in a high ionic-strength solution to provide a high hybridization efficiency. On the other hand, to reduce the screening of the DNA charge by counter ions and to achieve a high sensitivity, the sensor signal induced by the hybridization and denaturation events was measured in a low ionic-strength solution. High sensor signals of about 120, 90, and 80 mV were registered after the DNA hybridization, denaturation, and re-hybridization events, respectively. Fluorescence microscopy has been applied as reference method to verify the DNA immobilization, hybridization, and denaturation processes. An electrostatic charge-plane model for potential changes at the gate surface of a nanoplate field-effect sensor induced by the DNA hybridization has been developed taking into account both the Debye length and the distance of the DNA charge from the gate surface.
FH Aachen Dimensionen 01/12 Herausgeber : Rektor der FH Aachen Inhaltsverzeichnis Thema 06 Vielfalt integrieren - nachhaltig fördern | Mit einer systematischen Qualitätsentwicklung von Studium und Lehre reagiert die FH Aachen auf den Studienandrang 12 "Wir sprechen niemandem die Studierfähigkeit ab" | Prof. Helmut Jakobs und Dr. Michael Heger äußern sich zur Bildungspolitik und den Herausforderungen der Hochschule in den kommenden Jahren Studium 14 Extraraum für Aachen | NRW-Wissenschaftsministerin Svenja Schulze auf „Hochschul-Tour zum doppelten Abiturjahrgang“ 18 Wohnen auf Zeit | Studierende des Fachbereichs Architektur entwickeln temporäre Wohnformen für die Zeit des Studierendenandrangs 19 Spioniert mein Handy mich aus? | FH-Student Michael Stahl hat eine App geschrieben, die die Internet-Kommunikation seines Smartphones mitschneidet und auswertet 20 Hoch hinaus | FH Aachen entwickelt zusammen mit der Polytechnik- Universität ersten Architekturstudiengang in Namibia 22 Wenn ein Rad ins andere greift | FH Aachen bietet neuen Masterstudiengang „Automatisierungs- und Antriebstechnik“ erstmals im Sommersemester 2012 an 23 Stabiler Lichtbogen | Andreas Bügener testete für eine belgische Firma neuartige Schweißverfahren 24 Student Sven von Osten gewinnt Corporate-Design-Wettbewerb | „Elektromobilität Region Aachen“ hat ein neues Markenzeichen 26 Doppelt gemoppelt hält besser | Studiengang Bauingenieurwesen - Netzingenieur öffnet sich für Handwerksberufe 27 Meldungen / Studium International 28 Erstes Parabolrinnen-Kraftwerk in Thailand | FH-Absolventen waren am Bau der Anlage beteiligt 32 Zirvedekiler | Zwei FH-Professoren befinden sich „in bester Gesellschaft“ 34 Der High-Level-Master für Wirtschaftswissenschaftler | Der OpenBordersMBA punktet mit seiner Internationalität 36 Meldungen / International Forschung 38 Geheimnisvoller Eismond | FH Aachen entwickelt Technik für die Erforschung des Saturnmondes Enceladus 42 Wie ein Blitz | FH-Forscher entwickeln 3400 Grad heißen Plasma-Laser 44 Gegen den Durst | FH entwickelt für Namibia ein mehrstufiges System zur solarthermischen Grundwasseraufbereitung 46 Nachwuchs forscht | FH-Doktoranden präsentieren und diskutieren die Ergebnisse ihrer wissenschaftlichen Arbeit 48 „Global denken – lokal handeln“ | NOWUM-Energy gestaltet lokales Klimaschutzkonzept für Gangelt 49 Meldungen / Forschung Personen 50 „Plötzlich waren vier Kalaschnikows auf mich gerichtet“ | FH-Student Fabian Nawrath war sieben Monate mit dem Fahrrad in Afrika unterwegs 54 Der Ausdauernde | Kanzler Rainer Smeetz geht nach 38 Jahren in Ruhestand 55 Zum 100. Geburtstag von Wernher von Braun | FH veröffentlicht Sonderpublikation mit einem Essay von Prof. Dr. Jesco Freiherr von Puttkamer 56 Der Ingenieur der Phantasia-Welten | FH-Absolvent Ralf-Richard Kenter ist heute Chef des berühmtesten Freizeitparks Deutschlands 58 Verdienter Lohn | 56 Studierende erhalten ein Jahr lang ein Stipendium 60 Ehrenplakettenträger und Absolventen 2011 74 Personalia 76 Buchtipps 77 Neuberufene Professorinnen und Professoren 79 Ausscheidende Professoren 80 Nachwort | Aachener Flugpionier Richard Perlia mit 106 Jahren verstorben Service 82 „Helle Köpfe“ erforschen die Haut des Wassers | Prof. Dr. Günter Jakob Lauth erklärt Viertklässlern, was hinter der Oberflächenspannung steckt 84 Mobile Behörde | Ausländeramt des Kreises Düren bietet neuen Service am Campus Jülich 86 Über die Zukunft der Fachhochschulen | Gemeinsame Veranstaltung von GEW und FH Aachen 87 „Eine faire und transparente Lösung“ | Durch die Einführung flexibler Arbeitszeiten starten Mitarbeiterinnen und Mitarbeiter entspannt in den Arbeitstag 88 Meldungen / Service 90 Messen und Veranstaltungen 94 Ortswechsel / Dreiländereck 95 Impressum
Forschungsbericht / Themenheft : Querschnittsthemen 4 Grußwort Prorektorin Prof. Dr. rer. nat. Christiane Vaeßen 6 Highlightprojekte 8 Erfolgsmeldungen aus der Wissenschaft 10 Konstruktion, Planung und Gestaltung / Institut für Baustoffe und Baukonstruktionen (IBB) 12 Stahlbaulabor 13 Geografische Informationssysteme in der Gewässerplanung 14 Didaktisch visuelle Einführung in die Architektur des Aachener Doms 16 CIVITAS-DYN@MO 17 Laserinstallation „fluently scientific“ 18 Subversive Schönheit 19 Gestaltung als Tool Wirtschaftswissenschaften 24 Cross-cultural Training 26 Unternehmerische Orientierung in etablierten Unternehmen – der Einfluss des Top-Management-Führungsstils im internationalen Vergleich 28 LEAN LAB 30 QFD - Stand der Anwendung und Perspektiven in Deutschland 34 Entwicklung eines universellen Qualitätskontrollzentrums 35 Telekommunikationsmärkte der Zukunft MINT 38 Forschungsprojekt GPUFaserVis - Visualisierung von hochauflösenden Nervenfasern des Gehirns 39 "3rd pulse plasma bulb" (quasi-quecksilberfreie HF-Energiesparlampe) 40 Labor für Nuklearchemie 44 CHERNE - Die Erfolgsgeschichte eines Hochschulnetzwerks 46 Steigerung der Immunogenität von therapeutischen Impfstoffen gegen Krebs (INB) 47 Direkter Nachweis von geladenen Makromolekülen mit Feldeffekt-Biosensoren, "veredelt" mit Keramikoberflächen (INB) 48 Smartphones - kleine Alleskönner, die viel über uns wissen 49 Gebrauchstaugliche IT-Systeme für den Mittelstand 51 Engineering-Useability mit Motion-Controllern 52 Labor für Elektrische Antriebssysteme : Rapid-Control-Protoyping von Industrieantrieben 53 Einzelteilfertigung komplexer Endprodukte am Beispiel Zahntechnik und Goldschmiedekunst 55 Schadstoffarme Wasserstoff und Syngas-Verbrennung für die Energieversorgung von morgen 56 EC2GO – Thermomanagement im E-Carsharing 57 SORT Standardised On-Road Test Cycles 58 EIC – Exhaust Impulse Charger 59 Der Blitz – Doch nicht unberechenbar! Ein dynamisches Modell zur Berechnung von Einschlagstellen und Einschlagwahrscheinlichkeiten 60 ETL QUADRAT: Semantische Annotationen in ETL-Prozessen als Qualitäts- und Effizienztreiber für Datenaggregatoren im Internet 61 HiX4AGWS: History-tracing XML for an Actor-driven Grid-enabled Workflow System 62 Impressum