Refine
Year of publication
Institute
- Fachbereich Medizintechnik und Technomathematik (1928)
- Fachbereich Elektrotechnik und Informationstechnik (1150)
- Fachbereich Wirtschaftswissenschaften (1119)
- Fachbereich Energietechnik (1066)
- Fachbereich Chemie und Biotechnologie (892)
- Fachbereich Maschinenbau und Mechatronik (801)
- Fachbereich Luft- und Raumfahrttechnik (769)
- Fachbereich Bauingenieurwesen (664)
- IfB - Institut für Bioengineering (627)
- INB - Institut für Nano- und Biotechnologien (585)
Has Fulltext
- no (9284) (remove)
Language
Document Type
- Article (5518)
- Conference Proceeding (1413)
- Book (1057)
- Part of a Book (555)
- Patent (174)
- Bachelor Thesis (169)
- Report (82)
- Doctoral Thesis (79)
- Conference: Meeting Abstract (75)
- Other (67)
- Contribution to a Periodical (20)
- Review (18)
- Master's Thesis (17)
- Working Paper (13)
- Conference Poster (5)
- Habilitation (5)
- Preprint (5)
- Talk (5)
- Diploma Thesis (3)
- Part of a Periodical (2)
- Examination Thesis (1)
- Video (1)
Keywords
- Illustration (10)
- Nachhaltigkeit (10)
- Corporate Design (9)
- Erscheinungsbild (8)
- Gamification (8)
- Redesign (7)
- Animation (6)
- Datenschutz (6)
- Deutschland (6)
- Digitalisierung (6)
High-intensity discharge lamps can be driven by radio-frequency signals in the ISM frequency band at 2.45 GHz, using a matching network to transform the impedance of the plasma to the source impedance. To achieve an optimal operating condition, a good characterization of the lamp in terms of radio frequency equivalent circuits under operating conditions is necessary, enabling the design of an efficient matching network. This paper presents the characterization technique for such lamps and presents the design of the required matching network. For the characterization, a high-intensity discharge lamp was driven by a monofrequent large signal at 2.45 GHz, whereas a frequency sweep over 300 MHz was performed across this signal to measure so-called small-signal hot S-parameters using a vector network analyzer. These parameters are then used as an equivalent load in a circuit simulator to design an appropriate matching network. Using the measured data as a black-box model in the simulation results in a quick and efficient method to simulate and design efficient matching networks in spite of the complex plasma behavior. Furthermore, photometric analysis of high-intensity discharge lamps are carried out, comparing microwave operation to conventional operation.
The possibility of using the atomic-force microscopy as a method for detection of the analytical signal from plasticized polymeric sensor membranes was analyzed. The surfaces of cadmium-selective membranes based on two polymeric matrices were examined. The digital images were processed with multivariate image analysis techniques. A correlation was found between the surface profile of an ion-selective membrane and the concentration of the ion in solution.
A new trend in automation is to deploy so-called cyber-physical systems (CPS) which combine computation with physical processes. The novel RoboCup Logistics League Sponsored by Festo (LLSF) aims at such CPS logistic scenarios in an automation setting. A team of robots has to produce products from a number of semi-finished products which they have to machine during the game. Different production plans are possible and the robots need to recycle scrap byproducts. This way, the LLSF is a very interesting league offering a number of challenging research questions for planning, coordination, or communication in an application-driven scenario. In this paper, we outline the objectives of the LLSF and present steps for developing the league further towards a benchmark for logistics scenarios for CPS. As a major milestone we present the new automated referee system which helps in governing the game play as well as keeping track of the scored points in a very complex factory scenario.
The present work describes a novel multiple sensor-type system for the real-time analysis of aseptic sterilisation processes employing gaseous hydrogen peroxide (H2O2) as a sterilant. The inactivation kinetics of Bacillus atrophaeus by gaseous H2O2 have been investigated by means of a methodical calibration experiment, taking into account the process variables H2O2 concentration, humidity and gas temperature. It has been found that the microbicidal effectiveness at H2O2 concentrations above 2% v/v is largely determined by the concentration itself, while at lower H2O2 concentrations, the gas temperature and humidity play a leading role. Furthermore, the responses of different types of gas sensors towards the influencing factors of the sterilisation process have been analysed within the same experiment. Based on a correlation established between the inactivation kinetics and the sensor responses, a calorimetric H2O2 sensor and a metal-oxide semiconductor (MOX) sensor have been identified as possible candidates for monitoring the microbicidal effectiveness of aseptic sterilisation processes employing gaseous H2O2. Therefore, two linear models that describe the relationship between sensor response and microbicidal effectiveness have been proposed.
As a semiconductor-based electrochemical sensor, the light-addressable potentiometric sensor (LAPS) can realize two dimensional visualization of (bio-)chemical reactions at the sensor surface addressed by localized illumination. Thanks to this imaging capability, various applications in biochemical and biomedical fields are expected, for which the spatial resolution is critically significant. In this study, therefore, the spatial resolution of the LAPS was investigated in detail based on the device simulation. By calculating the spatiotemporal change of the distributions of electrons and holes inside the semiconductor layer in response to a modulated illumination, the photocurrent response as well as the spatial resolution was obtained as a function of various parameters such as the thickness of the Si substrate, the doping concentration, the wavelength and the intensity of illumination.
The simulation results verified that both thinning the semiconductor substrate and increasing the doping concentration could improve the spatial resolution, which were in good agreement with known experimental results and theoretical analysis. More importantly, new findings of interests were also obtained. As for the dependence on the wavelength of illumination, it was found that the known dependence was not always the case. When the Si substrate was thick, a longer wavelength resulted in a higher spatial resolution which was known by experiments. When the Si substrate was thin, however, a longer wavelength of light resulted in a lower spatial resolution. This finding was explained as an effect of raised concentration of carriers, which reduced the thickness of the space charge region.
The device simulation was found to be helpful to understand the relationship between the spatial resolution and device parameters, to understand the physics behind it, and to optimize the device structure and measurement conditions for realizing higher performance of chemical imaging systems.
Enceladus explorer - A maneuverable subsurface probe for autonomous navigation through deep ice
(2012)
IT Products are viewed and managed differently depending on the perspectives and the stage within the life cycle. A model is presented that integrates different perspectives and stages serving as an aid for the analysis of business models and focused positioning of IT-products. Four generic business models are analysed with regard to the product management function in general and the positioning field for IT-products specifically: off-the-shelf (license), license plus service, project, and system service (incl. cloud computing).
Two single-incision mini-slings used for treating urinary incontinence in women are compared with respect to the stresses they produce in their surrounding tissue. In an earlier paper we experimentally observed that these implants produce considerably different stress distributions in a muscle tissue equivalent. Here we perform 2D finite element analyses to compare the shear stresses and normal stresses in the tissue equivalent for the two meshes and to investigate their failure behavior. The results clearly show that the Gynecare TVT fails for increasing loads in a zipper-like manner because it gradually debonds from the surrounding tissue. Contrary to that, the tissue at the ends of the DynaMesh-SIS direct may rupture but only at higher loads. The simulation results are in good agreement with the experimental observations thus the computational model helps to interpret the experimental results and provides a tool for qualitative evaluation of mesh implants.
We analyze the trading behavior of individual investors in option-like securities, namely bankissued warrants, and thus expand the growing literature of investors behavior to a new kind of securities. A unique data set from a large German discount broker gives us the opportunity to analyze the trading behavior of 1,454 investors, making 89,958 transactions in 6,724 warrants on 397 underlyings. In different logit regression, we make use of the facts that investors can speculate on rising and falling prices of the underlying with call and put warrants and that we also have information about the stock portfolios of the investors. We report several facts about the trading behavior of individual investors in warrants that are consistent with the literature on the behavior of individual investors in the stock market. The warrant investors buy calls and sell puts if the price of the underlying has decreased over the past trading days and they sell calls and buy puts if the price of the underlying has increased. That means, the investors follow negative feedback trading strategies in all four trading categories observed. In addition, we find strong evidence for the disposition effect for call as well as put warrants, which is reversed in December. The trading behavior is also influenced if the underlying reaches some exceptionally prices, e.g. highs, lows or the strike price. We show that hedging, as one natural candidate to buy puts, does not play an important role in the market for bank-issued warrants.
Lagerstabiles flüssiges Wasch- oder Reinigungsmittel enthaltend Proteasen [Offenlegungsschrift]
(2011)
Mass transfer correlation for evaporation–condensation thermal process in the range of 70 °C–95 °C
(2013)
C-terminal truncation of a metagenome-derived detergent protease for effective expression in E. coli
(2010)
Recently, a new alkaline protease named HP70 showing highest homology to extracellular serine proteases of Stenotrophomonas maltophilia and Xanthomonas campestris was found in the course of a metagenome screening for detergent proteases (Niehaus et al., submitted for publication). Attempts to efficiently express the enzyme in common expression hosts had failed. This study reports on the realization of overexpression in Escherichia coli after structural modification of HP70. Modelling of HP70 resulted in a two-domain structure, comprising the catalytic domain and a C-terminal domain which includes about 100 amino acids. On the basis of the modelled structure the enzyme was truncated by deletion of most of the C-terminal domain yielding HP70-C477.
This structural modification allowed effective expression of active enzyme using E. coli BL21-Gold as the host. Specific activity of HP70-C477 determined with suc-l-Ala-l-Ala-l-Pro-l-Phe-p-nitroanilide as the substrate was 30 ± 5 U/mg compared to 8 ± 1 U/mg of the native enzyme. HP70-C477 was most active at 40 °C and pH 7–11; these conditions are prerequisite for a potential application as detergent enzyme. Determination of kinetic parameters at 40 °C and pH = 9.5 resulted in KM = 0.23 ± 0.01 mM and kcat = 167.5 ± 3.6 s⁻¹. MS-analysis of peptide fragments obtained from incubation of HP70 and HP70-C477 with insulin B indicated that the C-terminal domain influences the cleavage preferences of the enzyme. Washing experiments confirmed the high potential of HP70-C477 as detergent protease.
A large strain collection comprising antagonistic bacteria was screened for novel detergent proteases. Several strains displayed protease activity on agar plates containing skim milk but were inactive in liquid media. Encapsulation of cells in alginate beads induced protease production. Stenotrophomonas maltophilia emerged as best performer under washing conditions. For identification of wash-active proteases, four extracellular serine proteases called StmPr1, StmPr2, StmPr3 and StmPr4 were cloned. StmPr2 and StmPr4 were sufficiently overexpressed in E. coli. Expression of StmPr1 and StmPr3 resulted in unprocessed, insoluble protein. Truncation of most of the C-terminal domain which has been identified by enzyme modeling succeeded in expression of soluble, active StmPr1 but failed in case of StmPr3.
From laundry application tests StmPr2 turned out to be a highly wash-active protease at 45 °C. Specific activity of StmPr2 determined with suc-l-Ala-l-Ala-l-Pro-l-Phe-p-nitroanilide as the substrate was 17 ± 2 U/mg. In addition we determined the kinetic parameters and cleavage preferences of protease StmPr2.
Euler-based induced drag estimation for highly non-planar lifting systems during conceptional design
(2013)
This study describes a label-free impedimetric sensor based on short ssDNA recognition elements for the detection of hybridization events. We concentrate on the elucidation of the influence of target length and recognition sequence position on the sensorial performance. The impedimetric measurements are performed in the presence of the redox system ferri-/ferrocyanide and show an increase in charge transfer resistance upon hybridization of ssDNA to the sensor surface. Investigations on the impedimetric signal stability demonstrate a clear influence of the buffers used during the sensor preparation and the choice of the passivating mercaptoalcanol compound. A stable sensor system has been developed, enabling a reproducible detection of 25mer target DNA in the low nanomolar range. After hybridization, a sensor regeneration can be reached with deionized water by adjustment of effective convection conditions, ensuring a sensor reusability. By investigations of longer targets with overhangs exposed to the solution, we can demonstrate applicability of the impedimetric detection for longer ssDNA. However, a decreasing charge transfer resistance change (ΔRct) is found by extending the overhang. As a strategy to increase the impedance change for longer target strands, the position of the recognition sequence can be designed in a way that a small overhang is exposed to the electrode surface. This is found to result in an increase in the relative Rct change. These results suggest that DNA and consequently negative charge near the electrode possess a larger impact on the impedimetric signal than DNA further away.
One of the priority trends of carbon nanotechnology is creation of nanocomposite systems. Such carbon nanostructured composites were produced using - raw materials based on the products of agricultural waste, such as grape stones, apricot stones, rice husk. These products have a - wide spectrum of application and can be obtained in large quantities. The Institute of Combustion Problems has carried out the work on synthesis of the nanostructured carbon sorbents for multiple applications including the field of biomedicine. The article presents the data on the synthesis and physico-chemical properties of carbonaceous sorbents using physicochemical methods of investigation: separation and purification of biomolecules; isolation of phytohormone - fusicoccin; adsorbent INGO-1 in the form of an adsorption column for blood detoxification, oral (entero) sorbent - INGO-2; the study of efferent and probiotic properties and sorption activity in regard to the lipopolysaccharide (LPS), new biocomposites - based on carbonized rice husk (CRH) and cellular microorganisms; the use of CRH in wound treatment. A new material for blood detoxication (INGO-1) has been obtained. Adsorption of p-cresyl sulfate and indoxyl sulfate has shown that active carbon adsorbent can remove clinically significant level of p-cresyl sulfate and indoxyl sulfate from human plasma. Enterosorbent INGO-2 possesses high adsorption activity in relation to Gram-negative bacteria and their endotoxins. INGO-2 slows down the growth of conditionally pathogenic microorganisms, without having a negative effect on bifido and lactobacteria. The use of enterosorbent INGO-2 for sorption therapy may provide a solution to a complex problem - detoxication of the digestive tract and normalization of the intestinal micro ecology. The immobilized probiotic called "Riso-lact" was registered at the Ministry of Health of the Republic of Kazakhstan as a biologically active food additive. The developed technology is patented and provides production of the medicine in the form of freeze-dried biomass immobilized in vials.
Engineering of functional interfaces / Patrick Wagner ; Theodor Doll ; Michael J. Schöning (eds.)
(2014)
Wohnungseigentümergemeinschaft - Einstimmigkeitserfordernis bei Errichtung einer Mobilfunkantenne
(2014)
Der BGH (BGH v. 25.1.2014 – V ZR 48/13, MDR 2014, 399) hatte darüber zu befinden, ob auf dem Dach eines Hauses, das im Eigentum einer Wohnungseigentümergemeinschaft steht, auch gegen den Willen eines einzelnen Eigentümers eine Mobilfunkantenne angebracht werden kann. Das Urteil führt in das Spannungsfeld einer Abwägung zwischen Mehrheits- und Individualinteressen innerhalb einer WEG. Insoweit betont der BGH den grundsätzlichen Vorrang der Individualinteressen, jedenfalls soweit es um Beeinträchtigungen geht, die verständlicherweise von einem Eigentümer abgelehnt werden können. Der BGH verlangt im Ergebnis im Zweifel eine allseitige Zustimmung. Das Urteil ist zu begrüßen, lässt aber für die Zukunft Abgrenzungsfragen offen.
An array of electrically isolated nanoplate field-effect silicon-on-insulator (SOI) capacitors as a new transducer structure for multiparameter (bio-)chemical sensing is presented. The proposed approach allows addressable biasing and electrical readout of multiple nanoplate field-effect capacitive (bio-)chemical sensors on the same SOI chip, as well as differential-mode measurements. The realized sensor chip has been applied for pH and penicillin concentration measurements, electrical monitoring of polyelectrolyte multilayer formation, and the label-free electrical detection of consecutive deoxyribonucleic acid (DNA) hybridization and denaturation events.
A novel photoexcitation method for the light-addressable potentiometric sensor (LAPS) is proposed to achieve a higher spatial resolution of chemical images. The proposed method employs a combined light source that consists of a modulated light probe, which generates the alternating photocurrent signal, and a ring of constant illumination surrounding it. The constant illumination generates a sheath of carriers with increased concentration which suppresses the spread of photocarriers by enhanced recombination. A device simulation was carried out to verify the effect of constant illumination on the spatial resolution, which demonstrated that a higher spatial resolution can be obtained.
Heat production in the windings of the stators of electric machines under stationary condition
(2014)
In electric machines due to high currents and resistive losses (joule heating) heat is produced. To avoid damages by overheating the design of effective cooling systems is required. Therefore the knowledge of heat sources and heat transfer processes is necessary. The purpose of this paper is to illustrate a good and effective calculation method for the temperature analysis based on homogenization techniques. These methods have been applied for the stator windings in a slot of an electric machine consisting of copper wires and resin. The key quantity here is an effective thermal conductivity, which characterizes the heterogeneous wire resin-arrangement inside the stator slot. To illustrate the applicability of the method, the analysis of a simplified, homogenized model is compared with the detailed analysis of temperature behavior inside a slot of an electric machine according to the heat generation. We considered here only the stationary situation. The achieved numerical results are accurate and show that the applied homogenization technique works in practice. Finally the results of simulations for the two cases, the original model of the slot and the homogenized model chosen for the slot (unit cell), are compared to experimental results.
TOP-Energy : softwaregestützte Analyse und Optimierung industrieller Energieversorgungssysteme
(2004)
Mein Freund, die Uni
(2014)
"Biologie trifft Mikroelektronik", das Motto des Instituts für Nano- und Biotechnologien (INB) an der FH Aachen, unterstreicht die zunehmende Bedeutung interdisziplinär geprägter Forschungsaktivitäten. Der thematische Zusammenschluss grundständiger Disziplinen, wie die Physik, Elektrotechnik, Chemie, Biologie sowie die Materialwissenschaften, lässt neue Forschungsgebiete entstehen, ein herausragendes Beispiel hierfür ist die Nanotechnologie: Hier werden neue Werkstoffe und Materialien entwickelt, einzelne Nanopartikel oder Moleküle und deren Wechselwirkung untersucht oder Schichtstrukturen im Nanometerbereich aufgebaut, die neue und vorher nicht bekannte Eigenschaften hervorbringen.
Vor diesem Hintergrund bündelt das im Jahre 2006 gegründete INB die an der FH Aachen vorhandenen Kompetenzen von derzeit insgesamt sieben Laboratorien auf den Gebieten der Halbleitertechnik und Nanoelektronik, Nanostrukturen und DNA-Sensorik, der Chemo- und Biosensorik, der Enzymtechnologie, der Mikrobiologie und Pflanzenbiotechnologie, der Zellkulturtechnik, sowie der Roten Biotechnologie synergetisch. In der Nano- und Biotechnologie steckt außergewöhnliches Potenzial! Nicht zuletzt deshalb stellen sich die Forscher der Herausforderung, in diesem Bereich gemeinsam zu forschen und Schnittstellen zu nutzen, um so bei der Gestaltung neuartiger Ideen und Produkte mitzuwirken, die zukünftig unser alltägliches Leben verändern werden.
Im Folgenden werden die verschiedenen Forschungsbereiche kurz zusammenfassend vorgestellt und vorhandene Interaktionen anhand von exemplarisch ausgewählten, aktuellen Forschungsprojekten skizziert.
Nachdenklichkeit über Nachhaltigkeit : wie uns ein neues Wort alte Probleme neu entdecken läßt
(1997)
Differentiation between Phaeocystis pouchetii (Har.) Lagerheim and Phaeocystis globosa Scherffel
(1987)