Refine
Year of publication
- 2001 (106) (remove)
Institute
- Fachbereich Medizintechnik und Technomathematik (48)
- INB - Institut für Nano- und Biotechnologien (39)
- Fachbereich Elektrotechnik und Informationstechnik (20)
- Fachbereich Chemie und Biotechnologie (12)
- Fachbereich Energietechnik (11)
- Fachbereich Luft- und Raumfahrttechnik (6)
- Fachbereich Wirtschaftswissenschaften (5)
- Fachbereich Maschinenbau und Mechatronik (2)
- ECSM European Center for Sustainable Mobility (1)
- Fachbereich Gestaltung (1)
Language
- English (106) (remove)
Document Type
- Article (88)
- Conference Proceeding (12)
- Book (6)
Keywords
- Einspielen <Werkstoff> (2)
- Blitzschutz (1)
- Einspielanalyse (1)
- Erneuerbare Energien (1)
- FEM (1)
- Finite-Elemente-Methode (1)
- Hybridsystem (1)
- Lightning protection (1)
- Materialermüdung (1)
- Renewable energy (1)
Pulses from a position-sensitive photomultiplier (PS-PMT) are recorded by free-running ADCs at a sampling rate of 40 MHz. A four-channel acquisition board has been developed which is equipped with four 12-bit ADCs connected to one field programmable gate array (FPGA). The FPGA manages data acquisition and the transfer to the host computer. It can also work as a digital trigger, so a separate hardware trigger can be omitted. The method of free-running sampling provides a maximum of information, besides the pulse charge and amplitude also pulse shape and starting time are contained in the sampled data. This information is crucial for many tasks such as distinguishing between different scintillator materials, determination of radiation type, pile-up recovery, coincidence detection or time-of-flight applications. The absence of an analog integrator allows very high count rates to be dealt with. Since this method is to be employed in positron emission tomography (PET), the position of an event is also important. The simultaneous readout of four channels allows localization by means of center-of-gravity weighting. First results from a test setup with LSO scintillators coupled to the PS-PMT are presented here
Fatigue analyses are conducted with the aim of verifying that thermal ratcheting is limited. To this end it is important to make a clear distintion between the shakedown range and the ratcheting range (continuing deformation). As part of an EU-supported research project, experiments were carried out using a 4-bar model. The experiment comprised a water-cooled internal tube, and three insulated heatable outer test bars. The system was subjected to alternating axial forces, superimposed with alternating temperatures at the outer bars. The test parameters were partly selected on the basis of previous shakedown analyses. During the test, temperatures and strains were measured as a function of time. The loads and the resulting stresses were confirmed on an ongoing basis during performance of the test, and after it. Different material models were applied for this incremental elasto-plastic analysis using the ANSYS program. The results of the simulation are used to verify the FEM-based shakedown analysis.
The load-carrying capacity or the safety against plastic limit states are the central questions in the design of structures and passive components in the apparatus engineering. A precise answer is most simply given by limit and shakedown analysis. These methods can be based on static and kinematic theorems for lower and upper bound analysis. Both may be formulated as optimization problems for finite element discretizations of structures. The problems of large-scale analysis and the extension towards realistic material modelling will be solved in a European research project. Limit and shakedown analyses are briefly demonstrated with illustrative examples.
Characterising an insect antenna as a receptor for a biosensor by means of impedance spectroscopy
(2001)
Penicillin detection by means of field-effect based sensors: EnFET, capacitive EIS sensor or LAPS?
(2001)
An ISFET-based penicillin sensor with high sensitivity, low detection limit and long lifetime
(2001)
Novel concepts for flow-rate and flow-direction determination by means of pH-sensitive ISFETs
(2001)
Knowledge Management
(2001)
Thin film chemical sensors based on chalcogenide glasses for „electronic tongue“ applications
(2001)
Control of Aharonov-Bohm oscillations in a AlGaAs/GaAs ring by asymmetric and symmetric gate biasing
(2001)
Lightning protection design of a renewable energy hybrid-system without power mains connection
(2001)
Lightning protection design of a renewable energy hybrid-system without power mains connection
(2001)
In the year 2000 a direct lightning strike to the hybridsystem without power mains connection VATALI on the Greek island Crete results in the destruction and damage of some mechanical and electrical components. The hybrid-system VATALI was not lightning protected at that time. The hardware damage costs are approx. 60,000 €. The exposed site of the hybrid-system on top of a mountain was and still is the reason for a high risk of lightning strikes. Also in the future further lightning strikes have to be taken into consideration. In the paper a fundamental lightning protection design concept for renewable energy hybrid-systems without power mains connection and protection measures against direct strikes and overvoltages are shown in detail. The design concept was realized exemplarily for the hybrid-system VATALI. The hardware costs for the protection measures were about 15,000 €. About 50% of the costs are due to protection measures against direct strikes, 50% are due to overvoltage protection. Future extensions, new installations, or modifications have to be included into the lightning protection design concept of the hybrid-system.
Rapid Prototyping and PIV
(2001)
Laserwelding with fillerwire
(2001)