Exact Model Reduction for Damped-Forced Nonlinear Beams: An Infinite-Dimensional Analysis

We use invariant manifold results on Banach spaces to conclude the existence of spectral submanifolds (SSMs) in a class of nonlinear, externally forced beam oscillations. SSMs are the smoothest nonlinear extensions of spectral subspaces of the linearized beam equation. Reduction of the governing PDE to SSMs provides an explicit low-dimensional model which captures the correct asymptotics of the full, infinite-dimensional dynamics. Our approach is general enough to admit extensions to other types of continuum vibrations. The model-reduction procedure we employ also gives guidelines for a mathematically self-consistent modeling of damping in PDEs describing structural vibrations

Interleukin 31 mediates MAP kinase and STAT1/3 activation in intestinal epithelial cells and its expression is upregulated in inflammatory bowel disease

Background/aim: Interleukin 31 (IL31), primarily expressed in activated lymphocytes, signals through a heterodimeric receptor complex consisting of the IL31 receptor alpha (IL31R\textgreeka) and the oncostatin M receptor (OSMR). The aim of this study was to analyse IL31 receptor expression, signal transduction, and specific biological functions of this cytokine system in intestinal inflammation.Methods: Expression studies were performed by RT-PCR, quantitative PCR, western blotting, and immunohistochemistry. Signal transduction was analysed by western blotting. Cell proliferation was measured by MTS assays, cell migration by restitution assays.Results: Colorectal cancer derived intestinal epithelial cell (IEC) lines express both IL31 receptor subunits, while their expression in unstimulated primary murine IEC was low. LPS and the proinflammatory cytokines TNF-\textgreeka, IL1\textgreekb, IFN-\textgreekg, and sodium butyrate stimulation increased IL31, IL31R\textgreeka, and OSMR mRNA expression, while IL31 itself enhanced IL8 expression in IEC. IL31 mediates ERK-1/2, Akt, STAT1, and STAT3 activation in IEC resulting in enhanced IEC migration. However, at low cell density, IL31 had significant antiproliferative capacities (p<0.005). IL31 mRNA expression was not increased in the TNF\textgreekDARE mouse model of ileitis but in inflamed colonic lesions compared to non-inflamed tissue in patients with Crohn's disease (CD; average 2.4-fold increase) and in patients with ulcerative colitis (UC; average 2.6-fold increase) and correlated with the IL-8 expression in these lesions (r = 0.564 for CD; r = 0.650 for UC; total number of biopsies analysed: n = 88).Conclusion: IEC express the functional IL31 receptor complex. IL31 modulates cell proliferation and migration suggesting a role in the regulation of intestinal barrier function particularly in intestinal inflammation

An assessment of the correlation-based particle identification (CPI) method in the framework of Dual-Plane Stereo-Astigmatism (DPSA)

A synthetic study is conducted to assess the performance of the correlation-based particle identification method (CPI). As a technique developed in the context of Dual-Plane StereoAstigmatism (DPSA), the CPI method allows the identification of particle image shapes by utilizing image cross-correlation. The performance assessment addresses the influence of noise, particle density, particle image size and particle image deformation. The study shows viable results for low to moderate particle densities. Generally, a stronger performance of the CPI method is observed for small particle image sizes and pronounced particle image deformations. However, in the absence of particle overlapping, such as in the case of small particle densities, bigger particle images show a stronger performance, since a finer numerical discretization of the particle image provides a more accurate computation of the image cross-correlation. A stronger incorporation of particle overlapping increases the rate of particle identification, however it diminishes the accuracy of particle localization and particle allocation

Additive Manufactured Copper Conductors: Impedance Characteristics of Samples with Varying Density and Cross-section profile

With additive manufacturing, copper windings and even whole coils can be manufactured in a new, totally different approach than with common manufacturing methods. The coil design is no longer bound to the limitations given by the wires bend radius or the geometric capabilities of winding machines. Therefore, additive manufacturing offers new degrees of freedom for the design of copper windings and thus the design of electric machines. However, the electric properties of printed copper material must be known exactly and should be comparable to solid copper wire. This paper examines the impedance characteristics of additive manufactured copper conductors of two different copper alloys with varying print density and two different cross-section areas. Additionally, copper conductors consisting of multiple twisted subprofiles are examined, emulating stranded conductors. The measurement results are set in relation to an extruded copper profile to ensure comparability. The influence of the skin effect is examined by performing the investigations over a wide frequency range. Furthermore, the effect of different print densities on the effective resistance can be shown clearly. Besides the measurement results, an evaluation of the possible field of application and the limitations is given

Extensive geothermal heat use in cities energetic and economic comparison of options for thermal regeneration of the ground

Geothermal energy as a heat source for heat pumps is increasingly unused in the city of Zürich. However, as indicated by other authors, the renewable potential for shallow geothermal heat use is limited due to the fact that natural regeneration in the absence of ground water flow is slow. Constant heat extractions from dense geothermal heat pump installations continuously cool down the affected ground layer.. In this case boreholes have to be drilled deeper or regenerated in order to avoid freezing around the borehole. The aim of this simulation study is to find the most economic geothermal heat pump concept, which does not lead to borehole freezing after 50 years of operation in areas with dense installations (an exemplary mean geothermal heat extraction of 35kWh/m2/a was supposed for this this study). Therefor a multi-family house with a standard ground source heat pump was simulated for a period of 50 years in Polysun. Various solar concepts, an air heat exchanger concept, a geo cooling concept and also a system without regeneration were added to the system. These concepts were compared under the assumption that all neighboring installations are using an equivalent regeneration strategy as the simulated system For the different system concepts, highly variable total borehole length were needed to avoid freezing, reaching from 1020m for a system with a large glazed collector field to 2160m for the un-regenerated case. The heat cost of the analyzed system concepts was in the range of 21- 27 Rp/kWh. The most cost-effective system concepts according to this analysis are the air heat exchanger or unglazed collectors. Increasing the total borehole meters was not only one of the most expensive options, but also the least sustainable, since the continuation of ground tem-perature decrease after 50 years was more pronounced with this option than for any other option

A Primal-Dual Solver for Large-Scale Tracking-by-Assignment

We propose a fast approximate solver for the combinatorial problem known as tracking-by-assignment, which we apply to cell tracking. The latter plays a key role in discovery in many life sciences, especially in cell and developmental biology. So far, in the most general setting this problem was addressed by off-the-shelf solvers like Gurobi, whose run time and memory requirements rapidly grow with the size of the input. In contrast, for our method this growth is nearly linear. Our contribution consists of a new (1) decomposable compact representation of the problem; (2) dual block-coordinate ascent method for optimizing the decomposition-based dual; and (3) primal heuristics that reconstructs a feasible integer solution based on the dual information. Compared to solving the problem with Gurobi, we observe an up to~60~times speed-up, while reducing the memory footprint significantly. We demonstrate the efficacy of our method on real-world tracking problems.Comment: 23rd International Conference on Artificial Intelligence and Statistics (AISTATS), 202

Catch-Up 360: Digital Benefits for Physical Artifacts

ABSTRACT Industrial designers have a tangible working style. However, compared to digital data, physical mockups are difficult to copy and share over distance. They require a lot of physical space, and earlier versions are lost once they are modified. In this paper, we introduce Catch-Up 360, a tool designed for sharing physical mockups over distance to gain feedback from remote located designers, and compare current models with earlier versions. Summarizing, our approach provides a simple, intuitive, and tangible UI that supports the use of lightweight, web-based clients by using remote manipulation of the physical objects