Joint preload properties of structural threaded fasteners

Proper installation techniques are described and reliable torque-tension values are presented on joint preload /or clamp load/ properties of structural threaded fasteners

Suspended Load Path Tracking Control Using a Tilt-rotor UAV Based on Zonotopic State Estimation

This work addresses the problem of path tracking control of a suspended load using a tilt-rotor UAV. The main challenge in controlling this kind of system arises from the dynamic behavior imposed by the load, which is usually coupled to the UAV by means of a rope, adding unactuated degrees of freedom to the whole system. Furthermore, to perform the load transportation it is often needed the knowledge of the load position to accomplish the task. Since available sensors are commonly embedded in the mobile platform, information on the load position may not be directly available. To solve this problem in this work, initially, the kinematics of the multi-body mechanical system are formulated from the load's perspective, from which a detailed dynamic model is derived using the Euler-Lagrange approach, yielding a highly coupled, nonlinear state-space representation of the system, affine in the inputs, with the load's position and orientation directly represented by state variables. A zonotopic state estimator is proposed to solve the problem of estimating the load position and orientation, which is formulated based on sensors located at the aircraft, with different sampling times, and unknown-but-bounded measurement noise. To solve the path tracking problem, a discrete-time mixed $\mathcal{H}_2/\mathcal{H}_\infty$ controller with pole-placement constraints is designed with guaranteed time-response properties and robust to unmodeled dynamics, parametric uncertainties, and external disturbances. Results from numerical experiments, performed in a platform based on the Gazebo simulator and on a Computer Aided Design (CAD) model of the system, are presented to corroborate the performance of the zonotopic state estimator along with the designed controller

Private-Public Sector Cooperation in Combating Cybercrime: in Search of a Model

Turnover taxes are generally considered to be risk-free from the tax competition point of view, forthey are levied exclusively at the place of consumption. The Value-Added Tax (VAT) imposed by all EuropeanUnion (EU) member states, though, has become a source of distortion in the trans-Atlantic trade: non-EUsuppliers of electronic services were not required to collect the VAT, while their EU competitors were. The levelplaying field in EU’s foreign trade in electronic services was restored in 2002 by the so-called e-VAT Directivethat obliged non-EU providers of electronic services to charge the VAT at the rate of the member state theirconsumer resides in. This paper argues that besides being largely unenforceable, the Directive has createdanother misbalance in the infra-EU electronic commerce. It is being demonstrated that since the Directive is notapplicable to EU vendors, non-EU businesses can and do circumvent it by establishing daughter companies inEU jurisdictions with the lowest VAT rates and thus spur the infra-EU tax competition

Dokumentation 10 Jahre Leitbetriebe Ökologischer Landbau in Nordrhein-Westfalen

Inhaltsverzeichnis: Einleitung Ulrich Köpke Projekt „Leitbetriebe Ökologischer Landbau in NRW“: Forschung – Demonstration – Wissenstransfer Christoph Stumm, Martin Berg, Holger Schenke, Axel Schauder & Ulrich Köpke Volltext abrufbar unter https://orgprints.org/00002294/ Ökologischer Landbau in Nordrhein-Westfalen: Produktionsstruktur und räumliche Verteilung Guido Haas, Corinna Zerger, Karl Kempkens & Ulrich Köpke Volltext abrufbar unter https://orgprints.org/00001844/ Betriebsmanagement im Ökologischen Landbau: Analyse und Planung von Praxisbetrieben Guido Haas Volltext abrufbar unter https://orgprints.org/00002296/ Getreidebau Martin Berg, Holger Schenke, Jons Eisele, Edmund Leisen & Andreas Paffrath Volltext abrufbar unter https://orgprints.org/00001221/ Stickstoffmanagement im ökologisch wirtschaftenden Betrieb: Minderung von Stickstoffverlusten Martin Berg, Guido Haas, Edmund Leisen & Holger Schenke Volltext abrufbar unter https://orgprints.org/00002295/ Kartoffelanbau Andreas Paffrath, Edmund Leisen, Alfons Peine, Christine Vorländer, Martin Berg & Daniel Neuhoff Volltext abrufbar unter https://orgprints.org/00002299/ Untersaaten in Kartoffeln: Sonnenblume, Mais oder Gelbsenf Guido Haas Volltext abrufbar unter https://orgprints.org/00002322/ Anbau von Feldgemüse Andreas Paffrath, Edmund Leisen, Markus Puffert & Felix Lipper Volltext abrufbar unter https://orgprints.org/00002303/ Grünland und Futterbau Edmund Leisen Volltext abrufbar unter https://orgprints.org/00002304/ Rotkleegras: Arten- und Sortenwahl der Gräser Guido Haas Volltext abrufbar unter https://orgprints.org/00002323/ Milchviehhaltung Edmund Leisen & Peter Heimberg Volltext abrufbar unter https://orgprints.org/00002305/ Ausblick Ulrich Köpke & Karl Kempken

Developmental and functional effects of steroid hormones on the neuroendocrine axis and spinal cord

This review highlights the principal effects of steroid hormones at central and peripheral levels in the neuroendocrine axis. The data discussed highlight the principal role of oestrogens and testosterone in hormonal programming in relation to sexual orientation, reproductive and metabolic programming, and the neuroendocrine mechanism involved in the development of polycystic ovary syndrome phenotype. Moreover, consistent with the wide range of processes in which steroid hormones take part, we discuss the protective effects of progesterone on neurodegenerative disease and the signalling mechanism involved in the genesis of oestrogen-induced pituitary prolactinomas.Fil: Zubeldia Brenner, Lautaro. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Roselli, C. E.. Oregon Health and Science University Portland; Estados UnidosFil: Recabarren, S. E.. Universidad de Concepción; ChileFil: Gonzalez Deniselle, Maria Claudia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Lara, H. E.. Universidad de Chile; Chil

Assessment of the tissue distribution of transplanted human endothelial progenitor cells by radioactive labeling

Background— Transplantation of endothelial progenitor cells (EPCs) improves vascularization and left ventricular function after experimental myocardial ischemia. However, tissue distribution of transplanted EPCs has not yet been monitored in living animals. Therefore, we tested whether radioactive labeling allows us to detect injected EPCs

Entropic particle transport: higher order corrections to the Fick-Jacobs diffusion equation

Transport of point-size Brownian particles under the influence of a constant and uniform force field through a three-dimensional channel with smoothly varying periodic cross-section is investigated. Here, we employ an asymptotic analysis in the ratio between the difference of the widest and the most narrow constriction divided through the period length of the channel geometry. We demonstrate that the leading order term is equivalent to the Fick-Jacobs approximation. By use of the higher order corrections to the probability density we derive an expression for the spatially dependent diffusion coefficient D(x) which substitutes the constant diffusion coefficient present in the common Fick-Jacobs equation. In addition, we show that in the diffusion dominated regime the average transport velocity is obtained as the product of the zeroth-order Fick-Jacobs result and the expectation value of the spatially dependent diffusion coefficient . The analytic findings are corroborated with the precise numerical results of a finite element calculation of the Smoluchowski diffusive particle dynamics occurring in a reflection symmetric sinusoidal-shaped channel.Comment: 9 pages, 3 figure

Structure Space of Model Proteins --A Principle Component Analysis

We study the space of all compact structures on a two-dimensional square lattice of size $N=6\times6$. Each structure is mapped onto a vector in $N$-dimensions according to a hydrophobic model. Previous work has shown that the designabilities of structures are closely related to the distribution of the structure vectors in the $N$-dimensional space, with highly designable structures predominantly found in low density regions. We use principal component analysis to probe and characterize the distribution of structure vectors, and find a non-uniform density with a single peak. Interestingly, the principal axes of this peak are almost aligned with Fourier eigenvectors, and the corresponding Fourier eigenvalues go to zero continuously at the wave-number for alternating patterns ($q=\pi$). These observations provide a stepping stone for an analytic description of the distribution of structural points, and open the possibility of estimating designabilities of realistic structures by simply Fourier transforming the hydrophobicities of the corresponding sequences.Comment: 14 pages, 12 figures, Conclusion has been modifie

Sonoluminescing air bubbles rectify argon

The dynamics of single bubble sonoluminescence (SBSL) strongly depends on the percentage of inert gas within the bubble. We propose a theory for this dependence, based on a combination of principles from sonochemistry and hydrodynamic stability. The nitrogen and oxygen dissociation and subsequent reaction to water soluble gases implies that strongly forced air bubbles eventually consist of pure argon. Thus it is the partial argon (or any other inert gas) pressure which is relevant for stability. The theory provides quantitative explanations for many aspects of SBSL.Comment: 4 page