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Search Results: 1 - 10 of 256468 matches for " Stefan Brüggerhoff "
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Effects of Air Pollution on Materials and Cultural Heritage: ICP Materials Celebrates 25 Years of Research
Johan Tidblad,Vladimir Kucera,Martin Ferm,Katerina Kreislova,Stefan Brüggerhoff,Stefan Doytchinov,Augusto Screpanti,Terje Gr？ntoft,Tim Yates,Daniel de la Fuente,Ott Roots,Tiziana Lombardo,Stefan Simon,Markus Faller,Lech Kwiatkowski,Joanna Kobus,Costas Varotsos,Chris Tzanis,Linda Krage,Manfred Schreiner,Michael Melcher,Ivan Grancharov,Nadya Karmanova
International Journal of Corrosion , 2012, DOI: 10.1155/2012/496321
Abstract: An overview is given of all results from the International Co-operative Programme on Effects on Materials including Historic and Cultural Monuments (ICP Materials), which was launched in 1985. Since then, about twenty different materials have been exposed repeatedly in a network of test sites consisting of more than twenty sites with an extensive environmental characterisation and more than sixty official reports have been issued. Recent results on trends in corrosion, soiling, and pollution show that corrosion of carbon steel, zinc, and limestone is today substantially lower than 25 years ago, but while corrosion of carbon steel has decreased until today, corrosion of zinc and limestone has remained more or less constant since the turn of the century. Unique data are given on measured HNO3 concentrations from 2002-2003, 2005-2006, and 2008-2009, and the relative average decrease was about the same from 2002-2003 to 2005-2006 as it was from 2005-2006 to 2008-2009. 1. Introduction ICP Materials or “the International Co-operative Programme on Effects on Materials including Historic and Cultural Monuments” was launched in 1985 and had its first Task Force Meeting in March 10-11, 1986, Watford, United Kingdom. Since then, more than sixty reports in the official report series have been issued [1–66]. The history of ICP Materials [67] begins, however, with the history of the Convention on Long-range Transboundary Air Pollution (CLRTAP, LRTAP Convention or simply “the Convention”). In 1979, the Member States of the United Nations Economic Commission for Europe (UNECE) adopted the Convention as a response to acid rain, brought on by contamination of the air, killing forests and lakes even in remote places far from industrial facilities [68]. The Convention has been extended by eight protocols that identify specific measures to be taken by their 51 Parties to cut their emissions of air pollutants [69]. Worth mentioning in this context are the 1985 Protocol on the Reduction of Sulphur Emissions or their Transboundary Fluxes by at least 30 per cent, the 1994 Protocol on Further Reduction of Sulphur Emissions, and the 1999 Protocol to Abate Acidification, Eutrophication and Ground-level Ozone. The last of these is also named the “Gothenburg Protocol” or the “multipollutants/multi-effects protocol”. Already in 1980, Vladimir Kucera was approached by UNECE with a request to provide a short summary of the state of knowledge concerning the effects of sulphur compounds on materials. The reason for selecting Sweden was most likely due to Sweden’s well-received case study
Phosphatized embryo fossils from the Cambrian explosion
Zhao Yue,Stefan Bengtson,<br>
科学通报(英文版) , 1999,
Abstract: The earliest Cambrian (Meishucunian) phosphatized metazoanOlivooides from the Yangtze platform is represented by dierent developmental stages: from blastula through possible gastrula to tissue differentiation and finally to the hatched animals. The fossilization of embryos opens a new field in palaeontologypalaeoembryology. Embryological studies will be of importance for the understanding of ontogeny and phylogeny of metazoans from the Cambrian explosion.
Stabilization of Branching Queueing Networks
Tomá？ Brázdil,Stefan Kiefer
Computer Science , 2011,
Abstract: Queueing networks are gaining attraction for the performance analysis of parallel computer systems. A Jackson network is a set of interconnected servers, where the completion of a job at server i may result in the creation of a new job for server j. We propose to extend Jackson networks by "branching" and by "control" features. Both extensions are new and substantially expand the modelling power of Jackson networks. On the other hand, the extensions raise computational questions, particularly concerning the stability of the networks, i.e, the ergodicity of the underlying Markov chain. We show for our extended model that it is decidable in polynomial time if there exists a controller that achieves stability. Moreover, if such a controller exists, one can efficiently compute a static randomized controller which stabilizes the network in a very strong sense; in particular, all moments of the queue sizes are finite.
Synthesis of diverse indole libraries on polystyrene resin – Scope and limitations of an organometallic reaction on solid supports
Kerstin Knepper,Sylvia Vanderheiden,Stefan Br？se
Beilstein Journal of Organic Chemistry , 2012, DOI: 10.3762/bjoc.8.132
Abstract: The synthesis of diverse substituted indole structures on solid supports is described. The immobilization of nitrobenzoic acid onto Merrifield resin and the subsequent treatment with alkenyl Grignard reagents delivered indole carboxylates bound to solid supports. In contrast to results in the liquid phase, ortho,ortho-unsubstituted nitroarenes also delivered indole moieties in good yields. Subsequent palladium-catalyzed reactions (Suzuki, Heck, Sonogashira, Stille) delivered, after cleavage, the desired molecules in moderate to good yields over four steps. The scope and limitations are presented.
Kinects and Human Kinetics: A New Approach for Studying Crowd Behavior
Stefan Seer,Norbert Br？ndle,Carlo Ratti
Computer Science , 2012,
Abstract: Modeling crowd behavior relies on accurate data of pedestrian movements at a high level of detail. Imaging sensors such as cameras provide a good basis for capturing such detailed pedestrian motion data. However, currently available computer vision technologies, when applied to conventional video footage, still cannot automatically unveil accurate motions of groups of people or crowds from the image sequences. We present a novel data collection approach for studying crowd behavior which uses the increasingly popular low-cost sensor Microsoft Kinect. The Kinect captures both standard camera data and a three-dimensional depth map. Our human detection and tracking algorithm is based on agglomerative clustering of depth data captured from an elevated view - in contrast to the lateral view used for gesture recognition in Kinect gaming applications. Our approach transforms local Kinect 3D data to a common world coordinate system in order to stitch together human trajectories from multiple Kinects, which allows for a scalable and flexible capturing area. At a testbed with real-world pedestrian traffic we demonstrate that our approach can provide accurate trajectories from three Kinects with a Pedestrian Detection Rate of up to 94% and a Multiple Object Tracking Precision of 4 cm. Using a comprehensive dataset of 2240 captured human trajectories we calibrate three variations of the Social Force model. The results of our model validations indicate their particular ability to reproduce the observed crowd behavior in microscopic simulations.
Comparison of Different Control Algorithms for a Gantry Crane System  [PDF]
Stefan Bruins
Intelligent Control and Automation (ICA) , 2010, DOI: 10.4236/ica.2010.12008
Abstract: For a gantry crane system, this paper presents a comparison between four control algorithms. These algo-rithms are being compared on simplicity, stability and robustness. Goal for the controller is to move the load on a gantry crane to a new position with minimal overshoot of the load and maximal speed of the load. An-other goal is to provide an insight in the behaviour of the possible controllers. In this article a parallel P-controller, cascade P-controller, fuzzy controller and an internal model controller are used. To be able to validate and design the controllers a model is derived from the gantry crane. The controllers and the model are being implemented in Matlab Simulink. Finally the controllers are validated and tuned in Labview on a laboratory gantry scrane scale model. Main conclusion is that all presented controllers can be used as a con-troller for the gantry crane system but the fuzzy controller is showing the best performance.
Simulation and Injection Molding of Ring-Shaped Polymer Bonded Nickel Braze Metal Composite Preforms Based on Rheological and Thermal Analyses  [PDF]
Stefan Kirchberg
Open Journal of Composite Materials (OJCM) , 2013, DOI: 10.4236/ojcm.2013.32004
Abstract:

Rheological and thermal properties of LD-PE and LD-PE + 65 vol% Ni composite were examined by viscosity, pvt and thermal conductivity measurements at a wide range of shear rate, temperature and pressure. The typical shear-thinning viscosity of LD-PE polymer melt was enhanced up to four times by adding 65 vol% Ni braze metal particles. LD-PE show increasing specific volume versus temperature, decreasing with pressure and braze particle filler content. Variation of specific volume of LD-PE was reduced to 5% by admixing 65 vol% rigid Ni braze metal particles. Thermal conductivity of LD-PE was increased up to 15 times in the composite, reduced by decreasing pressure at temperature exceeding 80℃. Furthermore, thermal analysis was performed in modulated DSC to determine the specific heat capacity in wide temperature range. Viscosity and pvt-data were fitted using Cross-WLF equation and 2-domain Tait-pvt model, respectively. Simulation of LD-PE and LD-PE + 65 vol% Ni composite was performed based on rheological and thermal properties to define processing parameters. Simulation and injection molding of ring-shaped LD-PE + 65 vol% Ni composite braze metal preforms were performed successfully.

Creating a Strategic Partnership for Educating Nurse Practitioner Students about Sexual Health  [PDF]
Stefan Rowniak
Creative Education (CE) , 2014, DOI: 10.4236/ce.2014.515156
Abstract:

Sexual health is an essential and often neglected component of primary care. Nurse practitioners are ideal members of the healthcare team to be providing sexual health information, diagnoses, and treatments. Unfortunately, this is an area that has been lacking in the education of all healthcare providers. This paper describes a program that incorporates sexual health into the curriculum for nurse practitioner students through collaboration between the university school of nursing and the local health department. Given the increasing shortage of clinical sites and the need to train nurse practitioners to be competent in the delivery of sexual health, this is a model that could benefit other schools of nursing.

On the Stability of Stochastic Jump Kinetics  [PDF]
Stefan Engblom
Applied Mathematics (AM) , 2014, DOI: 10.4236/am.2014.519300
Abstract: Motivated by the lack of a suitable constructive framework for analyzing popular stochastic models of Systems Biology, we devise conditions for existence and uniqueness of solutions to certain jump stochastic differential equations (SDEs). Working from simple examples we find reasonable and explicit assumptions on the driving coefficients for the SDE representation to make sense. By “reasonable” we mean that stronger assumptions generally do not hold for systems of practical interest. In particular, we argue against the traditional use of global Lipschitz conditions and certain common growth restrictions. By “explicit”, finally, we like to highlight the fact that the various constants occurring among our assumptions all can be determined once the model is fixed. We show how basic long time estimates and some limit results for perturbations can be derived in this setting such that these can be contrasted with the corresponding estimates from deterministic dynamics. The main complication is that the natural path-wise representation is generated by a counting measure with an intensity that depends nonlinearly on the state.
Product Repositioning in the UK Newspaper Industry  [PDF]
Stefan Behringer
Theoretical Economics Letters (TEL) , 2016, DOI: 10.4236/tel.2016.65099
Abstract: This paper investigates the alleged predatory behaviour in the UK quality newspaper industry in the 1990s in terms of product repositioning using a horizontal differentiation model and industry data. It supports the call for an “effects based” approach to competition law by showing that non-price conduct can be a critical and less visible, complementary means to achieve a predatory goal than mere price cuts.
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