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- Zeitschriftenartikel (15) (entfernen)
Schlagworte
- Distributed fiber optic sensing (3)
- Structural health monitoring (3)
- Atmungssensor (2)
- Faseroptische Sensoren (2)
- Faseroptischer Sensor (2)
- Fiber optic sensor (2)
- Intelligente Textilien (2)
- OTDR (2)
- Acoustic emission analysis (1)
- Composite material (1)
- Cytop (1)
- Dehnungssensoren (1)
- Destructive testing (1)
- Distributed acoustic sensing (1)
- Distributed fiber sensing (1)
- Dosimetrie (1)
- Electron storage ring (1)
- Elektronenspeicherring (1)
- FBG (1)
- Faser-Bragg-Gitter (1)
- Fiber Bragg grating (1)
- Fiber Bragg gratings (1)
- Fiber optic sensors (1)
- Fiber-optic sensor (1)
- Fiberoptic sensor (1)
- Fire resistance (1)
- GFRP (1)
- Gamma radiation (1)
- Glass-fiber-reinforced plastic transport tank (1)
- Healthcare monitoring (1)
- Humidity induced annealing (1)
- Hybrid composite pressure vessel (1)
- Intelligent textile (1)
- Kavernenspeicher (1)
- Langperiodische Gitter (LPG) (1)
- MRI (1)
- Mac-robending sensor (1)
- Maschinelles Lernen (1)
- Material degradation (1)
- Mechanical characterization (1)
- Medical resonance imaging (MRI) (1)
- Medical textile (1)
- Medizinische Textilien (1)
- Mikrostrukturierte POF (mPOF) (1)
- Molecular alignment relaxation (1)
- Optical backscatter reflectometry (1)
- Optical fiber sensor climatic stability (1)
- Optical sensor (1)
- PMMA (1)
- POF (1)
- POF sensor (1)
- POF-Sensor (1)
- Perfluorinated polymer optical fibers (1)
- Phasenmesstechnik (1)
- Polycarbonate (1)
- Polymer fiber (POF) optical time domain reflectometry (OTDR) sensor (1)
- Polymer optical fiber (POF) sensor (1)
- Polymer optical fibers (1)
- Polymer optical fibres (1)
- Radiation dosimetry (1)
- Radiation sensors (1)
- Radiation-induced attenuation (1)
- Respiration sensor (1)
- Respiratory sensor (1)
- Rotorblatt (1)
- Smart medical textile (1)
- Smart textile (1)
- Strahlungssensoren (1)
- Stree-strain curve (1)
- Strukturüberwachung (1)
- Swept wavelength interferometry (1)
- Thermal annealing (1)
- Topas (1)
- Verbundwerkstoffe (1)
- Verteilte faseroptische Sensoren (1)
- Verteilte faseroptische akustische Sensorik (1)
- Wasserstoff-Druckbehälter (1)
- Wasserstoffspeicher (1)
- Windenergieanlagen (1)
- Zeonex (1)
Organisationseinheit der BAM
- 8 Zerstörungsfreie Prüfung (6)
- 8.6 Faseroptische Sensorik (6)
- 3 Gefahrgutumschließungen; Energiespeicher (2)
- 3.2 Gefahrguttanks und Unfallmechanik (1)
- 3.5 Sicherheit von Gasspeichern (1)
- 5 Werkstofftechnik (1)
- 5.3 Polymere Verbundwerkstoffe (1)
- 7 Bauwerkssicherheit (1)
- 7.5 Technische Eigenschaften von Polymerwerkstoffen (1)
The potential impact of optical fiber sensors embedded into medical textiles for the monitoring of respiratory movements in a magnetic resonance imaging environment is presented. We report on three different designs, all textile based: a macrobending sensor, a Bragg grating sensor, and a time reflectometry sensor. In all three cases, the sensing principle is based on the measure of the elongation of the abdominal circumference during breathing movements. We demonstrate that the three sensors can successfully sense textile elongations between 0% and 3%, while maintaining the stretching properties of the textile substrates for a good comfort of the patients.
Die Eignung von Faser-Bragg-Gitter-(FBG)-Sensoren zur Messung ionisierender Strahlung wurde an einem Undulator des Elektronenspeicherrings BESSY II untersucht. Über einen Zeitraum von 20 Wochen wurde eine durch Strahlung verursachte Bragg-Wellenlängenänderung der FBG-Sensoren von 25pm gemessen, was einer Strahlendosis von 720 Gy entspricht.
The suitability of using fiber Bragg grating (FBG) sensors for the measurement of ionizing radiation on the electron storage ring BESSY II by measuring the Bragg wavelength shift caused by radiation was investigated. During a time period of 20 weeks a Bragg wavelength shift of 25pm caused by the ionizing radiation was measured by FBG sensors at the storage ring. This Bragg wavelength shift corresponds to a radiation dose value of 720 Gy.
For patients under Magnetic Resonance Imaging (MRI) spontaneous respiration is constantly at risk of being impaired by anesthetic drugs or by upper airway obstruction. Therefore, continuous monitoring of the breathing activity is needed to assess adequate ventilation or to detect specific obstruction patterns. The paper describes three MRI compatible respiration sensors based on pure optical technologies developed within the EU FP6 project OFSETH. The sensors are based on fiber Bragg gratings, optical time-domain reflectometry and macrobending effects. The developed smart medical textiles can sense elongation up to 3% while maintaining the stretching properties of the textile substrates for patient's comfort. The OFSETH harness allows a continuous measurement of abdominal and thoracic respiration movement while all vitals organs are free for medical staff actions. The sensors were tested in MRI environment and on healthy adults.
The paper presents the first complex study of Gamma radiation effects on a low-loss perfluorinated polymer optical fiber (PF-POF) based on Cytop® polymer. Influence of gamma radiation on fiber’s optical, mechanical and climatic performance is investigated. The radiation-induced attenuation (RIA) in the visible and near-infrared region (0.4 μm-1.7 mm) is measured and its origins are discussed. Besides attenuation increase, radiation is also shown to decrease the thermal degradation stability of the fiber and to increase its susceptibility to water. With regard to complex fiber transmission performance upon irradiation, the optimal operation wavelength region of PF-POF-based systems intended for use in Radiation environments is determined to be around 1.1 μm. On the other hand, the investigated fiber holds potential for low-cost RIA-based optical fiber dosimetry applications with sensitivity as high as 260 dBm⁻¹/kGy in the visible region.
A systematic study of annealing behavior of drawn PMMA fibers was performed. Annealing Dynamics were investigated under different environmental conditions by fiber longitudinal shrinkage monitoring. The shrinkage process was found to follow a stretched exponential decay function revealing the heterogeneous nature of the underlying molecular dynamics. The complex dependence of the fiber shrinkage on initial degree of molecular alignment in the fiber, annealing time and temperature was investigated and interpreted. Moreover, humidity was shown to have a profound effect on the annealing process, which was not recognized previously. Annealing was also shown to have considerable effect on the fiber mechanical properties associated with the relaxation of molecular alignment in the fiber. The consequences of fiber annealing for the climatic stability of certain polymer optical fiber-based sensors are discussed, emphasizing the importance of fiber controlled pre-annealing with respect to the foreseeable
operating conditions.
The mechanical stress-strain behaviour of polymer optical fibres (POFs) drawn from various materials was measured, both before and after temperature annealing of the POFs. The POFs were drawn from PMMA (GEHR), Zeonex (480R), PC (Makrolon LED2245) and two different grades of Topas (8007S-04 and 5013S-04). With fibre drawing stresses at or above the elastic (uniaxial extensional) plateau modulus, the polymer chains in the POFs have a high degree of alignment, which has a large impact on fibre mechanical behaviour. The testing was performed at straining rates ranging from 0.011%/s, to 1.1%/s for the un-annealed fibres and a straining rate of 1.1%/s for the annealed ones. The elastic modulus of the tested POFs showed no sensitivity toward variation of straining rate. In the case of Topas 5013S-04 and PMMA, the producer-reported values are the same as the one obtained here for the POFs both before and after annealing. The drawn POFs made of Zeonex, PC, and Topas 8007S-04 exhibit larger elastic modulus than the respective materials in the bulk form. The elastic modulus of these fibres is reduced upon annealing by 10-15%, but still remains above the producer-reported values for the bulk polymers. In the nonlinear elastic region, only the PC POF is statistically unaffected by the changes in the straining rate, while Topas 8007S-04 POF shows insensitivity to the straining rate until 3% strain. All other changes affect the stress-strain curves. The annealing flattens all stress-strain curves, making the fibres more sensitive to yield.
For the purpose of increasing payload and reduce freight cost, lightweight composite tank containers used for Transportation have been progressively developed during the last years. Compared to conventionally produced cylindrical steel tanks, the fiber-reinforced solutions allow greater flexibility in the tank design. Despite a number of further material-related benefits of fiber-reinforced composites as non-conductive and non-magnetic behavior as well as corrosion resistance and high strength, the optimization of their thermal degradation properties during combustion is still a challenge. To improve the fire performance of lightweight composite containers, special intumescent fire protection coatings can be applied onto the outside tank surface. This paper presents fire tests on glass-fiber-reinforced plastic transport tanks with complex geometries sheltered with different surface-applied fire protection systems. To evaluate the fire resistance of the tank structures, a fiber optic monitoring system was developed. This system is based on distributed temperature measurements using high-Resolution optical backscatter reflectometry and pointwise reference measurements using fiber Bragg gratings. Thereby, all the fiber optic sensors were directly integrated in the composite layer structure of the tanks. The focus of the presented work is on the demonstration of capability of fiber optic monitoring system in such high-temperature application. Moreover, the fiber optic measurements provide new insights into the efficiency of intumescent coating applied for fire protection of fiber-reinforced plastic transport tanks.