535 research outputs found
Olfactory peptide production for gas phase biosensors
No full textAuthor Julian Widhalm, BScMasterarbeit Johannes Kepler Universität Linz 2025Arbeit gesperr
LINEAR FREQUENCY DOMAIN PREDICTIONS OF DYNAMIC DERIVATIVES FOR THE DLR F12 WIND TUNNEL MODEL
No full textStructural loads for full aircraft configurations can be represented by evaluating dynamic derivatives over a wide parameter space mainly including different mode shapes, an- gle of attack and Mach numbers. Traditionally, these values are determined by wind tunnel tests applying forced periodic motions to aircraft models. The ability of numerical simula- tions provide an excellent addendum to wind tunnel tests. Instead of time-accurate unsteady Reynolds-averaged Navier-Stokes (URANS) solvers which are recognized as extremely compu- tational expensive this paper considers a linearized frequency domain solver (LFD). With this approach the unsteady simulation reduces to a single steady state computation and a single linear simulation in the frequency domain. By the assumption of small perturbations and har- monic oscillations dynamic derivatives can be computed efficiently within a wide parameter space. In addition, the theoretical background for the LFD will be presented. Based on the linearization of the RANS equations and modeling of small perturbations with Fourier series a complex valued linear system has to be solved
Efficient Computation of Dynamic Stability Data with a Linearized Frequency Domain Solver.
No full textDetermination of aeroelastic stability boundaries for full aircraft configu-
rations by solving the time-accurate unsteady Reynolds-averaged Navier-Stokes (RANS)
equations is recognized as extremely computationally expensive or impractical. This is due
to the wide range of
flight conditions, frequencies, and structural deformation mode shapes
that must be examined to ensure a configuration is free from
flutter. Nonetheless there
is an increasing demand within the aerospace industry for accurate
utter analysis in the
transonic regime, which can only be satisfied with the use of high-fidelity RANS codes.
Hence we are motivated to seek a more efficient numerical method. By assuming that
perturbations to the
ow are small and harmonic, we can derive an efficient alternative
method by linearization of the RANS equations, a linearized frequency domain (LFD)
solver. With this approach the unsteady simulation reduces to a single non-linear steady
computation followed by a single linear simulation in the frequency-domain. This method
is not new, but has principally been applied to turbomachinery so far. The contribution
of this paper twofold: firstly to show that LFD is sufficiently accurate and reliable for
applications to aeroelastic problems that occur in external aerodynamics, and secondly to
demonstrate the speed-up that can be expected over full unsteady computations. Viscous
transonic analysis is carried out on complex geometries in three-dimensions. The results
show good agreement with full unsteady simulation and experiment, and a reduction in
computational costs up to one order of magnitude is demonstrated
Lagrangian Particle Tracking on Large Unstructured Three-Dimensional Meshes
No full textA prerequisite for the prediction of ice accretion on an aircraft flying
through clouds of supercooled liquid water is the accurate
determination of the water impingement rate on various components
of the aircraft. For this purpose, a droplet impingement module has been
developed using the datastructure of the unstructured Navier-Stokes
solver TAU. Since nowadays large computational grids are common
practice, an efficient algorithm for determination of the droplet
trajectories on such grids had to be implemented.
This paper describes the physics and details of the implemented
numerical algorithm. It summarizes lessons learned during
development. The paper concludes with the presentation of code
validation results and examples of applications
CP violation in B decays: Experimental aspects
No full textThis lecture, given at the 2005 European School of High-Energy Physics in Austria in succession of the series on CP Violation by Robert Fleischer, sheds light on the topic from a slightly different perspective, which is meant to be a link between theory and the daily work of experimentalists. An overview of Bmeson experimental history and phenomenology is followed by a description of B-meson production techniques, facilities worldwide, and a list of important present and future experiments. Current analyses are discussed, and their latest results (as of summer of 2005) are given
TEACHING LIVING SYSTEMS AWARENESS AS A CHANGE AGENT SKILL FOR A VIBRANT SUSTAINABLE WORLD
No full textHow can we design learning experiences so that they mimic an ecological, living system? How can learners fully experience the group as a living, vibrant, organic whole and unleash its creative? The process of stimulating “living systems awareness” and self-organizing creativity in learning communities, such as any courses, workshops, or conferences, is a truly integrative challenge that involves multiple dimensions of learning experience design: how we set up the visible and invisible learning space (structural-spatial dimension), how we pace and allow for flow according to nature’s rhythms (rhythmic-temporal dimension), how we allow for creative expression from the whole person (expressive-extrarational dimension), how we encourage the mind to understand and utilize systems analysis and systems design across disciplines (cognitive-rational dimension), and how we integrate this awareness in our practice (practical dimension). If all these aspects mimic and stimulate living systems dynamics, learners are more likely to co-create life-sustaining ideas, designs and structures. Particularly, there is value in nurturing autopoiesis in the classroom, which is a process of self-organizing, self-renewing development in living systems. When a system has a semi-permeable boundary, when there is rich information and resource exchange within that boundary, and when the system draws inspiration from its environment outside the boundary, something new arises that is greater than any participant could have come up with on their own. In order to revert the downward spiral of the industrial growth society, we urgently need to develop a multitude of life-sustaining innovations and regenerative design ideas in education. Because of the fragile state of the planet, an autopoietic approach to teaching is very timely. By integrating living systems awareness through multiple ways of knowing, learners can internalize the principles and processes that sustain all life on earth more fully and are therefore better prepared to take action in an increasingly unpredictable world. This paper explores how to utilize the principles of living systems as metapatterns to guide instructional design. It summarizes key insights from the author’s recently published dissertation Nature as Guide to Vibrant Learning. The author then introduces a series of guiding questions and instructional design examples that allow for the integration of living systems awareness in any project or group process, across multiple dimensions of learning experience design. Particular emphasis is placed on the structural-spatial, rhythmic-temporal, and expressive-extrarational dimension, which deserve much greater attention in education for a healthier world
Methylmercury Uptake into BeWo Cells Depends on LAT2-4F2hc, a System L Amino Acid Transporter
No full textThe organic mercury compound methylmercury (MeHg) is able to target the fetal brain. However, the uptake of the toxicant into placental cells is incompletely understood. MeHg strongly binds to thiol-S containing molecules such as cysteine. This MeHg-l-cysteine exhibits some structural similarity to methionine. System L plays a crucial role in placental transport of essential amino acids such as leucine and methionine and thus has been assumed to also transport MeHg-l-cysteine across the placenta. The uptake of methylmercury and tritiated leucine and methionine into the choriocarcinoma cell line BeWo was examined using transwell assay and small interfering (si)RNA mediated gene knockdown. Upon the downregulation of large neutral amino acids transporter (LAT)2 and 4F2 cell-surface antigen heavy chain (4F2hc), respectively, the levels of [H]leucine in BeWo cells are significantly reduced compared to controls treated with non-targeting siRNA (p < 0.05). The uptake of [H]methionine was reduced upon LAT2 down-regulation as well as methylmercury uptake after 4F2hc silencing (p < 0.05, respectively). These findings suggest an important role of system L in the placental uptake of the metal. Comparing the cellular accumulation of mercury, leucine, and methionine, it can be assumed that (1) MeHg is transported through system L amino acid transporters and (2) system L is responsible for the uptake of amino acids and MeHg primarily at the apical membrane of the trophoblast. The findings together can explain why mercury in contrast to other heavy metals such as lead or cadmium is efficiently transported to fetal blood.(VLID)486719
A TMS-EEG Exploration of Latent Working Memory
No full textThere has been much recent debate within the field of working memory (WM) on the storage mechanism (persistent delay-period activity vs. activity-silent) and storage location (frontal vs. sensory cortex) of latent WM items. This thesis addresses these debates using a novel combination of transcranial magnetic stimulation (TMS) and electroencephalography (EEG) with in a double retrocue working memory experiment. We found that participants had higher memory performance for unattended items when those items received TMS during a delay period as opposed to when those items were not directly targeted by TMS. This increase in behavioral performance was mirrored by a recovery of decoding ability for the item’s feature (i.e., orientation) as measured with the application of inverted encoding models to the EEG data. Specifically, unattended items that received TMS to contralateral, retinotopic visual cortex showed significant reconstruction of orientation whereas those items that received TMS to ipsilateral visual cortex did not. While concerns about data quality and TMS protocol (particularly for Experiment 2) limit the conclusions that can be drawn at present, the results from this thesis converge with other recent studies to provide support for the sensorimotor recruitment hypothesis and “activity-silent” retention mechanisms in WM.</p
Prevalence of prediabetes and type 2 diabetes in children with obesity and increased transaminases in European German‐speaking countries. Analysis of the APV initiative
No full textBACKGROUND: Non-alcoholic fatty liver disease (NAFLD), prediabetes and type 2 diabetes mellitus are known to be closely linked with obesity as early as during childhood. OBJECTIVES: The study aimed to determine the prevalence of prediabetes and T2DM in children with obesity with or without increased transaminases. METHODS: Data from the observational multicentre (n = 51), cross-sectional Adipositas Patienten Verlaufsbeobachtung registry were analyzed. Mild increase (mild group) was defined by alanine transaminase (ALT) >24 to ≤50 U/L and moderate to severe increase (advanced group) by ALT > 50 U/L. Prediabetes and T2DM were defined according to recent IDF/ISPAD guidelines. RESULTS: The prevalence of prediabetes and T2DM was 11.9% (95% CI: 11.0-12.8) and 1.4% (95% CI: 1.1-1.7) among all participants (n = 4932; male = 2481; mean age 12.9 ± 2.7 years; BMI-SDS 2.1 ± 0.5; Tanner stage 3.2 ± 1.5). The prevalence of impaired glucose metabolism (prediabetes and T2DM) was 13.8% (95% CI: 12.1-15.4) in the mild, 21.9% (95% CI: 18.8-25.1) in the advanced group, 10.7% (95% CI: 9.4-11.9) in the control group. Mild and advanced groups had greater odds ratios for prediabetes [1.42; 95% CI: 1.17-1.72, 2.26-fold; (1.78-2.86), respectively], the advanced group also for T2DM [2.39 (1.36-4.21)] compared to controls. While an increase in transaminases predominantly affected boys, girls within the advanced group had a higher T2DM prevalence than males (5.4 vs. male 2.1%). CONCLUSIONS: Children with obesity and increased liver transaminases as surrogates of NAFLD should be screened for T2DM
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