PDE-restringierte Optimierung in Anwendungen der spanenden Trockenbearbeitung

Nowadays industrial manufacturing is highly widespread while the demand of high-precision manufacturing is increasing constantly. In such processes, it is common to apply coolants to reduce the thermal stress of workpieces and tools as well as to guarantee the functional performance of the final parts. Nonetheless, there are several reasons like cost reduction and ecological benefits for omitting coolants or to use minimum quantity lubrication (MQL). In order to satisfy the quality standards in dry machining, compensation strategies of shape deviations are necessary. Due to the increasing digitalization of process chains (Industry 4.0), modern sensors and the usage of high-performance computing, nonlinear optimization is more convenient than ever before. In this context, a prediction model is required by which the machining can be optimized. In this work a hybrid approach is used to model thermo-elastic effects as well as geometrical deviations caused by a change of the residual stress state. Physical correlations of the modeling which are not investigated yet can be synthesized by empirical regression with a wide variety of data. The first part of this elaboration is the determination of heat fluxes in milling and drilling which cana t be measured directly. One goal is to utilize nonlinear optimization to solve parameter identification problems. The second part is the minimization of shape deviations in dry milling processes by means of the hybrid model. To achieve this, different milling strategies are compared and machining parameters are optimized with nonlinear optimization techniques, while an efficient machining process is sought at the same time. The mathematical majority of this work covers the PDE-constrained optimization. Still a challenging topic in this field is the treatment of complex problems involving high computational costs. It is still advisable to increase the efficiency of the optimization methods whereby the accuracy of the underlying model can be improved. One promising approach is the Simultaneous Analysis and Design (SAND) where a discretized PDE act as constraints of the optimization. This approach gives importance to exploiting the system structure of the optimization problem. Another common method is the Nested Analysis and Design (NAND). Theoretical considerations suggest that the SAND approach favored in this work has computational benefits for treating nonlinear PDEs. Beside the successful application of the SAND approach in dry machining one goal is to provide evidence of its computational efficiency

Automated Polarization-dependent Multidimensional Coherent Spectroscopy Phased Using Transient Absorption

: An experimental apparatus is described for multidimensional optical spectroscopy with fully automated polarization control, based on liquid crystal variable retarders. Polarization dependence of rephasing two-dimensional coherent spectra are measured in a single scan, with absolute phasing performed for all polarization configurations through a single automated auxiliary measurement at the beginning of the scan. A factor of three improvement in acquisition time is demonstrated, compared to the apparatus without automated polarization control. Results are presented for a GaAs quantum well sample and an InGaAs quantum well embedded in a microcavit

Autonomous navigation of ships by combining optimal trajectory planning with informed graph search

Autonomous trajectory generation plays an essential role in the navigation of vehicles in space as well as in terrestrial scenarios, i.e. in the air, on solid ground, or water. For the latter, the navigation of ships in ports has specific challenges since ship dynamics are highly nonlinear with limited agility, while the manoeuvre space in ports is limited. Nevertheless, for providing support to humanly designed control strategies, autonomously generated trajectories have not only to be feasible, i.e. collision-free but shall also be optimal with respect to manoeuvre time and control effort. This article presents a novel approach to autonomous trajectory planning on the basis of precomputed and connectable trajectory segments, the so-called motion primitives, and an A*-search algorithm. Sequences of motion primitives provide an initial guess for a subsequent optimization by which optimal trajectories are found even in terrains with many obstacles. We illustrate the approach with different navigation scenarios

Antisemitische und rassistische Objekte und Bilder in Ausstellungen? : ein Gespräch über erprobte Strategien und offene Fragen

Etwas zeigen und dabei doch nichts reproduzieren; etwas sagen und doch genug Raum für Fragen lassen – kaum möglich? Die drei Autorinnen, Kuratorinnen und Forscherinnen des Beitrags gehen diesen zentralen Fragen der Ausstellungspraxis nach und zeigen erprobte Beispiele des Zeigens von antisemitischen und rassistischen Objekten und Bildern in Ausstellungen. Im Mittelpunkt stehen Strategien wie an unterschiedlichen Orten mit den verschiedenen Akteurskonstellationen ein Zeigen ohne Reproduktion von Stereotypen und ein Diskutieren mit vielen offenen Fragen möglich ist. Nicht im Sinn von Best practice, sondern als Labor, wie neue Wege des Ausstellungsmachens im Dialog mit den Besuchenden beschritten werden können

Superficial femoral popliteal vein: An anatomic study

AbstractObjective : The superficial femoral popliteal vein (SFPV) has been used as an alternative conduit for both arterial and venous reconstructive surgery. Its popularity continues to grow, despite concern about the potential for venous morbidity after harvest. The purpose of this study was to determine an anatomic “safe” length of SFPV for harvest, assuming that the preservation of at least one valve and one significant collateral vein in the remaining popliteal vein (PV) segment can minimize venous morbidity. Methods : Forty-four SFPVs were harvested from 39 cadaveric specimens. The length of both the superficial femoral vein (SFV) and PV was measured, and the number and location of valves and significant side branches (more than 2 mm in diameter) of the PV were measured. The Student two-tailed t test was used as a means of comparing vein lengths between the sexes. Correlation coefficients were determined for the effect of patient height on vein length, stratified by means of sex. Results : Vein length (SFV mean, 24.4 ± 4 cm; PV mean, 18.8 ± 4 cm) varied with sex (male SFV mean, 28.1 ± 5 cm; male PV mean, 21.5 ± 3 cm; female SFV mean, 22.6 ± 4 cm; female PV mean, 18.4 ± 3 cm; P =.01). Valve number (mean, 1.8 ± 0.5) and location and collateral vein number (mean, 5 ± 1.8) and location were variable and independent of height or sex. Conclusion : An anatomic “safe” length of SFPV for harvest to minimize venous morbidity would include all the SFV and 12 cm of PV in 95% of women and 15 cm of PV in 95% of men. We found that the male sex was a significant determinant for a longer safe length of vein that can be harvested. (J Vasc Surg 2000;31:450-5.

Die Internationalität der Rassenforschung im 20. Jahrhundert

Kühl S. Die Internationalität der Rassenforschung im 20. Jahrhundert. In: Foroutan N, Geulen C, Illmer S, Vogel K, Wernsing S, eds. Das Phantom "Rasse". Zur Geschichte und Wirkungsmacht von Rassismus. Schriften des Deutschen Hygiene-Museums Dresden. Vol 13. Köln: Böhlau; 2018: 105-111

Cleda Wernsing Interview, ca. 1979

Cleda Wernsing was born in Illinois and was 83 years old. Her father was a farmer and her family moved to Minnesota because of cheaper land. In this interview, Cleda discusses the changes Chokio and Johnson have undergone over the years. She discusses what they did for a social life. She also talks about some of the changes in home appliances over the years.https://digitalcommons.morris.umn.edu/kmrs/1163/thumbnail.jp

General and Special Education Co-teachers' Perspectives: the Experiences of Students with Emotional Disturbance Included in the General Education Classroom

This study examined elementary General Education (GenEd) and Special Education (SPED) co-teachers' perceptions of the academic and social-emotional experiences of students with Emotional Disturbance (ED) included in the GenEd classroom. Perceptions of overall academic and social-emotional experiences of students with ED, and specific facilitators and barriers to their success in the GenEd setting, were analyzed. Basic qualitative research was used to provide teachers who work directly with these students in the GenEd setting an opportunity to share their perspective on the experiences of their students with ED. The framework of the study incorporated Lerner's (1985) theory of developmental contextualism, as well as Nirje and Wolfensberger's (1970) principle of normalization. The study design included individual interviews with six GenEd teachers and six SPED teachers using a semi-structured protocol, as it provided a guide for each interview while allowing individual perspectives to emerge (Patton, 1990). Teachers confirmed they had co-taught at least one student with the primary disability of ED in the GenEd setting within the past academic year and held full licensure in either GenEd or SPED. Interviews were transcribed verbatim, coded, and analyzed using ATLAS.ti software. Reflective memos were used throughout the research process to organize questions, thoughts, speculations, and personal reactions about the interview data and themes (Creswell, 2007). Emergent themes clustered around the importance of relationships, characteristics of students with ED that enabled success, and factors in the GenEd setting that had a positive impact. Themes related to relationships included the importance of relationships between teachers and students' family, teachers and students with ED, GenEd and SPED co-teachers, and GenEd peers and students with ED. Themes related to characteristics of students with ED included preparedness, social-emotional competency, and perspectives. Themes related to factors in the GenEd classroom included consistency and structure, instructional efficacy, sense of community, and understandings of disability. Insight gained from this study highlights the need for preparation of students with ED with skills to be successful in the GenEd classroom, preparation of GenEd and SPED teachers working with this population, and encourages continued research on how to create successful inclusive environments for students with ED