7,596 research outputs found
Nicolai Hartmann. Biografia di un Pensiero
No full textIl progetto di ricerca è focalizzato sulla figura di Nicolai Hartmann (1882-1950). Tramite una ricostruzione storico-biografica e la contestualizzazione di numerosi materiali inediti, la ricerca si è condensata nella restituzione della complessa figura di Nicolai Hartmann, tenendo conto della sua intera produzione filosofica, attenta al profilo storico che ha connotato una delle carriere più interessanti e controverse del Novecento.The project is focused on the figure of Nicolai Hartmann (1882-1950). Through a historical-biographical reconstruction and the contextualization of numerous unpublished materials, the research condensed into the restitution of the complex figure of Nicolai Hartmann, taking into account his entire philosophical production
Magnetohydrodynamic turbulence in a Hartmann duct flow at finite magnetic Reynolds number
No full textThe dynamics of turbulent flow at finite magnetic Reynolds numbers can be very complex due to the coupled nature of the evolution equations for the flow and magnetic fields. In this regime, the Hartmann flow in a straight rectangular duct with streamwise periodicity is studied with the help of direct numerical simulations (DNS) and the effect of magnetic Reynolds number on turbulent statistics is quantified by comparing the results with the numerical results obtained using the quasistatic approximation
Análisis de la reconstrucción topográfica de superficies cónicas de revolución en función del desenfoque cuando se emplea la prueba de Hartmann para superficies convexas.
No full textSe implementa la prueba de Hartmann modificada en configuración telecéntrica, para la reconstrucción de superficies cónicas a partir de patrones de Hartmann tomados en diferentes posiciones axiales de la superficie de prueba. La evaluación de cada patrón se hace por medio de un algoritmo basado en la geometría del sistema, con trazo exacto de rayos y la ley vectorial de reflexión. Las relaciones entre los coeficientes del ajuste en series de McLaurin de las superficies reconstruidas, permiten calcular el radio en el vértice y constante cónica reales de la superficie, incluso si no se tomó registro del patrón de Hartmann en la posición óptima de enfoque. Se analizan los factores experimentales que inducen error en la medición al caracterizar tres superficies cónicas fabricadas en polimetilmetacrilato (elipsoide con R=8.5 mm y paraboloide con R=6.5 mm) y vidrio BK7 (esfera con R=7.8 mm).Abstract. A modified Hartmann test in telecentric configuration is experimentally implemented to reconstruct conic surfaces from a set of Hartmann patterns obtained for different axial positions of the test surface. Each pattern is evaluated through an algorithm based on the system geometry, which involve exact ray tracing and the vector form of the re ection law. The relations between the coeficients of the McLaurin series fitting for each reconstructed surface, allow to determine the real values of vertex radius and conic constant of the surface, even if not a single Hartmann pattern was taken in the best focus position. Experimental facts wich induce error in the measurement are analyzed with the characterization of three conic surfaces fabricated in PMMA (ellipsoid with R = 8;5 mm and paraboloid with R = 6;5 mm) and BK7 glass (sphere with R = 7;8 mm).Maestrí
JCR_TUD_Supplemental_1_Literature – Supplemental material for Liquid chromatography–mass spectrometry analysis of cationic aniline dyes from the Technical University of Dresden Historical Collection of Dyes
No full textSupplemental material, JCR_TUD_Supplemental_1_Literature for Liquid chromatography–mass spectrometry analysis of cationic aniline dyes from the Technical University of Dresden Historical Collection of Dyes by Michael John Plater, Andrea Raab and Horst Hartmann in Journal of Chemical Research</p
sj-docx-1-chl-10.1177_17475198231196759 – Supplemental material for Violet dyes of the 1860s: Hofmann, Britannia, violet de Paris, Wanklyn’s, and Crystal violet (1883)
No full textSupplemental material, sj-docx-1-chl-10.1177_17475198231196759 for Violet dyes of the 1860s: Hofmann, Britannia, violet de Paris, Wanklyn’s, and Crystal violet (1883) by M John Plater, Andrea Raab and Horst Hartmann in Journal of Chemical Research</p
Bettina Fritzsche / Jutta Hartmann / Andrea Schmidt / Anja Tervooren (Hrsg.): Dekonstruktive Pädagogik. Erziehungswissenschaftliche Debatten unter poststrukturalistischen Perspektiven. Opladen: Leske und Budrich 2001 (314 S.) [Rezension]
No full textRezension von: Bettina Fritzsche / Jutta Hartmann / Andrea Schmidt / Anja Tervooren (Hrsg.): Dekonstruktive Pädagogik. Erziehungswissenschaftliche Debatten unter poststrukturalistischen Perspektiven. Opladen: Leske und Budrich 2001 (314 S.; ISBN 3-8100-3038-4; 22,50 EUR)
JCR_TUD_Supplemental_2_Photographs – Supplemental material for Liquid chromatography–mass spectrometry analysis of cationic aniline dyes from the Technical University of Dresden Historical Collection of Dyes
No full textSupplemental material, JCR_TUD_Supplemental_2_Photographs for Liquid chromatography–mass spectrometry analysis of cationic aniline dyes from the Technical University of Dresden Historical Collection of Dyes by Michael John Plater, Andrea Raab and Horst Hartmann in Journal of Chemical Research</p
The European framework on the liability arising from the use of Artificial Intelligence systems and its impact on UAS
No full textShack-Hartmann reflective micro profilometer
No full textWe present a quantitative phase imaging microscope based on a Shack-Hartmann sensor, that directly reconstructs the optical path difference (OPD) in reflective mode. Comparing with the holographic or interferometric methods, the SH technique needs no reference beam in the setup, which simplifies the system. With a preregistered reference, the OPD image can be reconstructed from a single shot. Also, the method has a rather relaxed requirement on the illumination coherence, thus a cheap light source such as a LED is feasible in the setup. In our previous research, we have successfully verified that a conventional transmissive microscope can be transformed into an optical path difference microscope by using a Shack-Hartmann wavefront sensor under incoherent illumination. The key condition is that the numerical aperture of illumination should be smaller than the numerical aperture of imaging lens. This approach is also applicable to characterization of reflective and slightly scattering surfaces.Team Raf Van de Pla
Deep Learning Wavefront Sensing: Via Raw Shack-Hartmann Images
No full textThe Delft Center for Systems and Control (DCSC) 'Smart Optics' aim to achieve higher resolution imaging through Adaptive Optics (AO). Adaptive optics is a modern technique for detecting and correcting real-time wavefront aberrations and is widely used in biomedical imaging and astronomical imaging. Wavefront sensing lies at the core of Adaptive Optics and is known to pose some challenges. Measurement of the wavefront cannot be done directly and has to be estimated through an intensity distribution on a detector. One approach to wavefront sensing is by using a Shack-Hartmann (SH) sensor. A Shack-Hartmann sensor (a pupil-plane sensor) subdivides the wavefront into N spatial areas using sub-apertures. The individual slopes across all sub-apertures are integrated to reconstruct the wavefront. The major advantage of using a Shack-Hartmann sensor is its fast operation speed, caused by the linear relationship between local slopes and original wavefront. This enables real-time wavefront reconstruction. The Shack-Hartmann sensor however, has some limitations. Its ability to reconstruct higher-order aberrations is restricted by the amount of lenses within the micro-lens array. Furthermore, a centroiding algorithm is used to compute the local slopes. Going from spots to centroids decreases the amount of informative pixels and greatly limits its wavefront reconstruction potential. Moreover, these centroiding algorithms often add a measure of uncertainty since spots can have irregular shapes or cross-over/overlap. In this Master Thesis a novel approach to phase reconstruction from the raw SH measurement is proposed. Here, we show that Deep Learning techniques in combination with a micro-lens array can surpass traditional SH phase reconstruction methods and alleviate their current limitations. The proposed method uses the entire Shack-Hartmann Pattern (HP) as input to a neural network, supplying the network with more information than existing Deep Learning SHWR methods, which still rely on centroids. Using this approach, we can combine the accuracy of sensor-less techniques with the speed of a Shack-Hartmann sensor. Three different neural network architectures are considered in this thesis. Two of these neural networks (Alex-Net and Xception) are adapted to output a series of Zernike coefficients. Using these estimated Zernike coefficients, a wavefront can be reconstructed. The remaining neural network, U-Net, performs a direct pixel-wise estimation of the phase-map. The input Shack-Hartmann patterns are created using different micro-lens array (MLA) geometries, consisting of 25-, 256- or 900 lenses. The networks are evaluated on their ability to reconstruct a combination of 32- or 100- Zernike coefficients.Mechanical Engineering | Systems and Contro
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