Materialien & Produktionstechnik
Refine
Year of publication
Document Type
- Article (147)
- conference proceeding (article) (54)
- Part of a Book (12)
- conference proceeding (presentation) (9)
- Report (3)
- conference proceeding (proceeding) (2)
- Other (2)
- Book (1)
Language
- English (184)
- German (45)
- Multiple languages (1)
Reviewed
Keywords
- Schneckengetriebe (7)
- Fiber optics (6)
- Holzbau (4)
- Optische Polymerfaser (4)
- Sensors (4)
- Tribologie (4)
- diamond (4)
- Integrierte Optik (3)
- NV-center (3)
- Nichtabbildende Optik (3)
Institute
- Institut für Chemie, Material- und Produktentwicklung (80)
- Fakultät für Elektrotechnik Feinwerktechnik Informationstechnik (57)
- Fakultät Maschinenbau und Versorgungstechnik (53)
- Fakultät Verfahrenstechnik (48)
- Polymer Optical Fiber Application Center (33)
- Fakultät Werkstofftechnik (29)
- Fakultät Angewandte Mathematik, Physik und Allgemeinwissenschaften (14)
- Partikeltechnologien, Rohstoffinnovationen und Ressourceneffizienz (8)
- Fakultät für Angewandte Chemie (7)
- Fakultät Architektur (6)
This file contains a script for determining band gaps from DRS measurements using a semi-automatic approach to eliminate potential user bias during the fitting procedure. The methods are based on the publications from J. Tauc, Materials Research Bulletin, vol. 3, no. 1, Jan. 1968 and P. Makuła, et al., The Journal of Physical Chemistry Letters, vol. 9, no. 23, Dec. 2018.
This work compares three experimental methods for determining the rotation angle and position of polarization-maintaining fibers for use in integrated fiber arrays: detection of the front-face panda structure, polarization measurements of the light guided by the fiber, and imaging the panda structures via the lateral view of the fiber. Position and rotational angle of the PM fiber are detected via image recognition algorithms. Achieved positional accuracies lie in the sub-micrometer range, rotational accuracies in the range of 0.01 rad corresponding to a polarization extinction ratio of > 40 dB.
As part of the Bavarian research project BayWater, which focuses on the use of membrane technologies for sustainable industrial water treatment, we are working with the IWC at TUM on an advanced oxidation process (AOP) based on peroxydisulfate (S2O82-). This process is intended to be used as a pre-treatment for wastewater in reverse osmosis (RO) plants, with the aim of minimizing membrane fouling. In addition to the low binding energy of peroxydisulfate (120 kJ·mol–1) and the associated high activation efficiency, peroxydisulfate offers advantages in terms of safety, storage stability and the associated costs. One way to activate and thus generate sulfate radicals from peroxydisulfate is by irradiation with light, especially in the UV range. The oxidation performance can be controlled via the optical power of the sources used in a way that minimizes fouling without damaging the membrane. For this reason, the aim is to design an AOP flow reactor using powerful UV LEDs on the basis of laboratory tests. Peroxydisulfate exhibits much higher extinction in the UVC region, which favors UVC activation. UVA LEDs, however, are significantly more energy-efficient, making them attractive from an operational standpoint. Therefore, the choice of the most suitable AOP light source should be based on experimental data. The radical-production efficiency of UV activation will be analyzed using a liquid-chromatography–based method and evaluated by the number of radicals generated per unit of energy consumed. The results will contribute to evaluating the feasibility of employing UV LEDs in AOP applications as an alternative to traditional mercury lamps.
This study valorizes granite sawing waste and kaolin through production of durable ceramics tiles. FactSage (8.4) thermochemical software was integrated with petrography, XRD, XRF, DTA-TGA, SEM-EDX, physico-mechanical, hot-stage microscopy, dilatometry, chemical durability tests and Raman spectroscopy to investigate the green materials and ceramics sintered at 900-1250 °C/h. Results show that Al/Si, Ca/Si, and Ca/Al ratios and impurities levels control feldspar crystallization, glassy phase formation, and the development of silicate melt with variable viscosities. The optimum composition (40 wt% granite waste at 1200 °C/h) has a compact, interlocked microstructure with ∼47 wt% melt and suitable viscosity (2.41 × 105 PaS), yielding negligible water absorption (0.19%), low porosity (0.46%), high flexural strength (52 MPa), controlled thermal expansion (5.42 × 10−6 C−1), and excellent acidic/alkali durability (0.48, 0.06 wt%) as well as acceptable geometric stability. However, 50 wt% granite waste involvement caused deformation at 1200 °C, and bloating occurring at 1250 °C. Ceramic tiles at 1200 °C are promising for heavy-duty industrial flooring applications.
Photonics has become a key enabling technology across a wide range of industrial optical systems. Throughout my professional career, I have observed its application in diverse fields, including ophthalmology, industrial metrology, and space-based optical instrumentation. This exposure spans a broad spectrum of technical developments, from startup-driven, hand-held devices to complex, multi-million-euro instruments developed over many years. These experiences have provided insight into the factors that determine whether technical systems ultimately succeed or fail, highlighting the critical role of robust photonic design and system-level engineering.
Following a transition from industry back to academia, my objective is to transfer an engineering-oriented perspective into applied academic research. In particular, the focus is on identifying optical architectures that exhibit inherent robustness with respect to environmental disturbances and manufacturing imperfections, and on systematically leveraging tolerance analysis as an integral element of the optical design process rather than as a final validation step.
This contribution further discusses how these industrial design principles are incorporated into ongoing research activities in the field of quantum technologies at the university of applied sciences Nuremberg, Germany. Emphasis is placed on the application of robust optical design methodologies to quantum photonic systems, thereby reinforcing the connection between industrial system engineering and applied academic research in photonics and quantum optics.
Caking and powder adhesion are widespread challenges in dry powder processes. The influence of process parameters such as humidity and temperature on the adhesion behavior of dry powders has been extensively studied in numerous studies. Besides that, the impact of other process characteristics, such as additional process parameters or wall materials, has received little attention so far. In addition, existing methods to characterize caking behavior do not account for powders in a fluidized state. To address phenomena based on process and material behavior, a test rig was specifically designed to investigate the adhesion of dry particles to different metal walls at varying speeds at a 90° angle, representing the main novelty of this study. The deposition area, deposition mass, and maximum deposition thickness were evaluated, and the correlations were discussed. The investigations revealed that at low velocities (<12 m/s) and for smooth surfaces (Sq < 0.3–0.4 µm), wall materials with a high ratio of dispersive to polar surface energy components (D/P: 13–15.8) exhibit minimal powder adhesion. The test rig has demonstrated its effectiveness as a straightforward method for measuring adhesion across various powder–wall material pairs and could serve as a valuable preliminary test for industrial applications.
Efficient collection of fluorescence light is essential for all optically adressable qubit platforms. For the nitrogen-vacancy (NV) center in diamond, the high refractive index of the host medium poses a major challenge as it limits the solid angle under which fluorescence light can leave the crystal. To enhance collection efficiency from single NV centers, we design and simulate micro-optical elements that shall be directly fabricated on the diamond surface using two-photon polymerization. Several optical designs and photoresists are evaluated for their expected coupling efficiency into single-mode fibers and their tolerance to fabrication errors. Additionally, an analytical solution for single lens collimation of the emission of a point source in diamond at a specific wavelength is presented, as well as considerations regarding the degradation of wavefront quality in multi-wavelength Fresnel designs.
Feine Pulver neigen stark zur Anhaftungs- und Klumpenbildung. Selbst bei streng kontrollierten Umgebungsbedingungen und minimalen mechanischen Belastungen tritt dieses Problem weiterhin auf. Besonders ausgeprägt ist das Phänomen bei Partikeln kleiner als 100 μm, für die die Schwerkraft praktisch keine Rolle mehr spielt [1]. Wechselwirkungen zwischen Partikeln sowie zwischen Partikeln und Wandoberflächen führen zu Ablagerungen, die die Qualität und Sicherheit des Endprodukts beeinträchtigen und im Zeitverlauf Produktionsausfälle verursachen können [2 – 4]. Ein Beispiel für Caking in einem gasdurchströmten System zeigt Abb. 1 anhand einer Laborspiralstrahlmühle. Im Projekt „Fluid-Cake“ wird das Caking-Phänomen an fluidisierten Systemen untersucht. Für die praktische und schnelle Untersuchung des Anhaftungsverhaltens unterschiedlicher Pulver wurde ein Pulverversuchsstand konstruiert, in dem verschiedene Produkte direkt getestet werden können. Der Versuchsstand bietet den Vorteil, dass unterschiedliche Einflussfaktoren – wie Pulver- und Partikeleigenschaften, Wahl der Prozessparameter und Wandmaterialien – gemeinsam bewertet werden können. Während bisherige Untersuchungen die Abhängigkeit des Adhäsionsverhaltens von Wandmaterialien, Pulverbeladungen und gewählten Gasgeschwindigkeiten gezeigt haben, werden in aktuellen Studien zusätzlich der Einfluss von Pulvereintreffwinkeln, Beschichtungs-stoffen und Reinigungsansätzen sowie die Modifikation des Kohäsionsverhaltens durch den Einsatz flüssiger Additive untersucht. Parallel werden die Pulver- und Partikeleigenschaften charakterisiert und die relevanten Fluidisierungssysteme mittels CFD nachgebildet. Diese vielseitige Herangehensweise ermöglicht eine umfassende Analyse der Faktoren, die das Caking-Phänomen beeinflussen, und liefert praxisrelevante Empfehlungen für die Auswahl geeigneter Pulver und Prozessparameter bereits in der Planungsphase.
Flexible Hybrid Electronics (FHE) is the combination of film substrates with etched or printed conductors and conventional SMT components. A particular focus has been placed on thermoplastics such as polyethylene terephthalate (PET) as a low-cost substrate material. However, the use of these materials in standard reflow soldering processes remains a challenge. In addition to the substrate's limited temperature resistance, the dissolution of printed silver conductors in the molten solder over time presents a further challenge.
The approach presented in this work uses multiple individually controllable Near Infrared LEDs as an energy source to selectively irradiate and thus locally heat FHE assemblies as required. Irradiation is applied from below through the substrate material, thereby enabling direct heating of the solder joint whilst preventing shading by the component body. The temporal and local controllability of the irradiation allows the placement density and the omission of temperature sensitive areas to be taken into account. This approach enables a more material-friendly and energy-efficient soldering process.