Eldorado - Repositorium der TU Dortmund

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Aktuellste Veröffentlichungen

Characterization of classical light fields for quantum applications via optical homodyne tomography
(2026) Brune, Yannik; Aßmann, Marc; Weitenberg, Christof
The goal of this work is to examine the coherence of classical light fields in order to assess their usefulness for quantum-informational tasks and to draw conclusions about the properties of the light source. To this end, we use and extend several optical homodyne tomography techniques employing four-port, eight-port, and sixteen-port detection schemes. To understand the role of coherence of a light field in solving a quantum informational task such as coherent qubit control, we begin by analyzing the qubit excitation process from a resource-theoretical perspective. By simulating the light-matter interactions, we demonstrate how the quantum coherence of the driving light field emerges as a key ingredient for coherent qubit control. At the same time, we show how the presence of thermal noise or dephasing significantly degrades the achievable quantum coherence of the light field. After studying the coherence properties of conventional lasers, we turn to non-conventional coherent light sources and investigate the emission of a non-resonantly excited exciton-polariton condensate. By employing long-lived polaritons and minimizing interactions with the reservoir, we optimize the condensation process and achieve a pronounced buildup of quantum superpositions in the condensate immediately above the condensation threshold. Finally, we shift our focus entirely to the matter system itself and use the coherence of the emitted light field to investigate its dynamics. For this purpose, we introduce a sixteen-port detection scheme that enables non-stationary and conditional analyses tailored to the requirements of semiconductor spectroscopy. Benchmarking the setup with a thermal light field, then demonstrate how we can resolve the stochastic fluctuations of the thermal state on the femtosecond level. Overall, our results establish connections between quantum optics, quantum information science, and semiconductor physics, providing insights relevant for quantum technologies and future hybrid quantum devices.
Mechanisms of drug release from a melt-milled, poorly soluble drug substance
(Elsevier BV, 2024-10-18) Sleziona, Dominik; Ely, David R.; Thommes, Markus
Increasing the dissolution kinetics of low aqueous soluble drugs is one of the main priorities in drug formulation. New strategies must be developed, which should consider the two main dissolution mechanisms: surface reaction and diffusion. One promising tool is the so-called solid crystal suspension, a solid dispersion consisting of purely crystalline substances. In this concept, reducing the drug particle size and embedding the particles in a hydrophilic excipient increases the dissolution kinetics. Therefore, a solid crystal suspension containing submicron drug particles was produced via a modified stirred media milling process. A geometrical phase-field approach was used to model the dissolution behavior of the drug particles. A carrier material, xylitol, and the model drug substance, griseofulvin, were ground in a pearl mill. The in-vitro dissolution profile of the product was modeled to gain a deep physical understanding of the dissolution process. The used numerical tool has the potential to be a valuable approach for predicting the dissolution behavior of newly developed formulation strategies.
Iterative real-time optimization of a membrane pilot plant
(Elsevier BV, 2024-03-16) Ahmad, Afaq; Paulen, Radoslav; Valo, Richard; Fikar, Miroslav; Engell, Sebastian
In this paper, we describe the implementation and experimental validation of iterative real-time optimization (RTO) at a continuously operated membrane separation pilot plant. The objective is to achieve an economically optimal operation using the transmembrane pressure and the feed flow rate as adjustable operational parameters (set-points for the lower-level plant controllers). In spite of the popularity of RTO based on rigorous nonlinear plant models in the research literature, its practical use so far remains limited to large scale plants in the petrochemical industries. The main issue behind the limited application of RTO schemes is the necessary effort to derive and maintain sufficiently accurate models of the plants. In case of a significant plant-model mismatch, the results are not reliable, the optimal performance is not reached and even systematic violations of constraints may occur. The applicability of RTO could be extended significantly if simple process models sufficed for its successful application. Then an adaptation of the model or of the optimization problem to the real behavior of the plant is necessary to achieve an optimal operation. For this example, we tackle this issue by applying an iterative scheme called modifier-adaptation with quadratic approximation in combination with model adaptation to ensure the convergence of the plant to the true process optimum despite the fact that the model has deficiencies. The experimental results show that, in spite of a considerable plant-model mismatch, the presented RTO scheme is capable of boosting the process economics.
Iterative real-time optimization of a reductive amination process in a thermomorphic multiphase system
(Elsevier BV, 2024-01-02) Gottu Mukkula, Anwesh Reddy; Riemer, Tim Benjamin; Kühl, Alexander; Vogt, Dieter; Engell, Sebastian
In this paper, we discuss the optimization of the operation of a reductive amination (RA) reaction process in a miniplant without an accurate process model using iterative real-time optimization (RTO). The rhodium-catalyzed RA of undecanal with diethylamine produces a tertiary amine from a long-chain aldehyde and is performed in a thermomorphic multiphase system (TMS) to recover and reuse the expensive catalyst efficiently. An iterative RTO method called modifier adaptation with quadratic approximation (MAWQA) is used in combination with guaranteed model adequacy (GMA) to drive the RA process to its optimum iteratively. MAWQA utilizes online measurements to overcome model deficiencies. GMA ensures that the model used in MAWQA satisfies the model adequacy conditions. The optimal operating conditions of the RA process in the miniplant were identified during an experimental run of the plant, thereby validating the applicability and efficiency of MAWQA with GMA. The results illustrate the benefits of process optimization using iterative RTO methods without accurate process models.
A catalogue of trustmaking practices
(2026-06-03) Budrys, Žemartas; Budryte, Paulina; Felderer, Brigitte; Hackl, Veronika; Hafner, Sebastian; Kränzle, Elina; Lee, Dahae; Lehner, Judith M.; Musch, Marcel. W.; Ranalli, Francesca; Romm, Thomas; Surizehi, Kamran; Vitkutė, Eglė; Weger, Kim; Zaat, Noor