375 research outputs found

    Quasi-dynamic global strength analysis of a passenger ship in regular waves

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    The current boom in cruise and passenger ship markets has led to a corresponding increase in the size of ships and their structural complexity. However, the optimization of capital expenditure costs remains a critical part in the design and construction of such ships. Additionally, the designers have at their disposal state-of-the-art tools and rational design methods for design and structural strength assessment of ships to ensure sufficient functional safety margins, especially for ships with general particulars and structural features that are not covered by the existing empirical Classification Rules. This master's thesis presents a rational quasi-dynamic response approach for the evaluation of global loads of passenger vessels. A rational quasi-dynamic response method couples wave-induced hydrodynamic pressures with a rigid hull idealization performed with ANSYS AQWA and ANSYS SpaceClaim. The CAD structural model of a typical cruise ship was produced using CADMATIC Hull with basic design accuracy. Furthermore, it was sufficiently optimized in ANSYS SpaceClaim to obtain an FEA model comprising of shell elements representing the primary and secondary parts of the structure. NAPA software was used for evaluating the still water bending moment. Consequently, the 3D diffraction/radiation panel code ANSYS AQWA was used to define the wave pressures acting on the hull and loads were mapped on the hull surface and transferred to the ANSYS FEM solver for hydro-structure coupling. As a result, still water and wave bending moments are received as well as the ship’s response. Comparisons against Class Society Rule wave bending moment amidships demonstrates that the direct evaluation of the wave bending moment and shear force envelopes along the hull girder may be a preferred rational approach in terms of assuring global structural strength and optimizing total steel weight. The outcomes of the thesis were presented during the Baltic Seas International Maritime Conference on 24.09.201

    WristFlex: low-power gesture input with wrist-worn pressure sensors

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    In this paper we present WristFlex, an always-available on-body gestural interface. Using an array of force sensitive resistors (FSRs) worn around the wrist, the interface can distinguish subtle finger pinch gestures with high accuracy (>80 %) and speed. The system is trained to classify gestures from subtle tendon movements on the wrist. We demonstrate that WristFlex is a complete system that works wirelessly in real-time. The system is simple and light-weight in terms of power consumption and computational overhead. WristFlex's sensor power consumption is 60.7 uW, allowing the prototype to potentially last more then a week on a small lithium polymer battery. Also, WristFlex is small and non-obtrusive, and can be integrated into a wristwatch or a bracelet. We perform user studies to evaluate the accuracy, speed, and repeatability. We demonstrate that the number of gestures can be extended with orientation data from an accelerometer. We conclude by showing example applications.National Science Foundation (U.S.) (NSF award 1256082

    Individual Legal Acts in the Tax Law of Russia

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    Artykuł został poświęcony indywidualnym aktom prawnym wydawanym przez organy podatkowe w Rosji. Akty te są prawnymi faktami, które powodują powstanie, zmianę lub wygaśnięcie stosunków podatkowych. Rosyjski Kodeks Podatkowy wprowadza ich zamknięty system. W treści opracowania autor definiuje indywidualne akty prawne organów podatkowych, analizuje ich strukturę, formy, procedury uchwalania, jak również dokonuje ich klasyfikacji.The Russian Academy of Justices (Russia

    Performance of a CsI(Tl) calorimeter in an experiment with stopped K+'s

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    The performance of the photon detector constructed for the search of T-violation in the decay K^+ -> pi^0 mu^+ nu is presented. The specific features of this detector consisting of 768 CsI(Tl) crystals with PIN photodiode readout for high precision measurement of T-odd correlations in the decays of positive kaons are considered.Comment: 11 pages, 10 figures, talk at the INSTR02 Conference, Novosibirsk, Russia, February 28 - March 6, 200

    Dynamic Nuclear Polarization in Silicon Microparticles

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    We report record high Si-29 spin polarization obtained using dynamic nuclear polarization in microcrystalline silicon powder. Unpaired electrons in this silicon powder are due to dangling bonds in the amorphous region of this intrinsically heterogeneous sample. Si-29 nuclei in the amorphous region become polarized by forced electron-nuclear spin flips driven by off-resonant microwave radiation while nuclei in the crystalline region are polarized by spin diffusion across crystalline boundaries. Hyperpolarized silicon microparticles have long T1 relaxation times and could be used as tracers for magnetic resonance imaging.Comment: 4 pages, 5 figures, published versio

    Chirally-modified metal surfaces: energetics of interaction with chiral molecules

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    Imparting chirality to non-chiral metal surfaces by adsorption of chiral modifiers is a highly promising route to create effective heterogeneously catalyzed processes for the production of enantiopure pharmaceuticals. One of the major current challenges in heterogeneous chiral catalysis is the fundamental-level understanding of how such chirally-modified surfaces interact with chiral and prochiral molecules to induce their enantioselective transformations. Herein we report the first direct calorimetric measurement of the adsorption energy of chiral molecules onto well-defined chirally-modified surfaces. Two model modifiers 1-(1-naphthyl)ethylamine and 2-methylbutanoic acid were used to impart chirality to Pt(111) and their interaction with propylene oxide was investigated by means of single-crystal adsorption calorimetry. Differential adsorption energies and absolute surface uptakes were obtained for the R- and S-enantiomers of propylene oxide under clean ultrahigh vacuum conditions. Two types of adsorption behavior were observed for different chiral modifiers, pointing to different mechanisms of imparting chirality to metal surfaces. The results are analyzed and discussed in view of previously reported stereoselectivity of adsorption processe

    Verbesserung der Performance von virtuellen Sensoren in totzeitbehafteten Prozessen

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    Modellbasierte virtuelle Sensoren (VS) ermöglichen die Messung von qualitätsbestimmenden Prozessparametern (bzw. Hilfsregelgrößen) dort, wo eine direkte Messung zu teuer oder gar nicht möglich ist. Für die adaptiven VS, die ihr internes Prozessmodell nach Data-Driven-Methode bilden (z. B. durch die Benutzung künstlicher neuronaler Netze (KNN)), besteht das Problem der Abschätzung der Prädiktionsstabilität. Aktuelle Lösungsansätze lösen dieses Problem nur für wenige KNN-Typen und erfordern enormen Entwurfs- und Rechenaufwand. In dieser Arbeit wird eine alternative Methode vorgestellt, welche für eine breite Klasse von KNN gilt und keinen hohen Entwurfs- und Rechenaufwand erfordert. Die neue Methode wurde anhand realer Anwendungsbeispiele getestet und hat sehr gute Ergebnisse geliefert. Für die nicht adaptiven virtuellen Sensoren wurde eine aufwandsreduzierte Adaption nach Smith-Schema vorgeschlagen. Dieses Verfahren ermöglicht die Regelung totzeitbehafteter und zeitvarianter Prozesse mit VS in einem geschlossenen Regelkreis. Im Vergleich zu anderen Regelungsstrategien konnte damit vergleichbare Regelungsqualität bei einem deutlich geringeren Entwurfsaufwand erzielt werden.Model-based virtual sensors allow the measurement of parameters critical for process quality where a direct measurement is too expensive or not at all possible. For the adaptive virtual sensors built after data-driven method (e.g., by use of an ANN model) there is a problem of the prediction stability. Current solutions attempt to solve this problem only for a few ANN types and require a very high development effort. In this dissertation a new method for the solution of this problem is suggested, which is valid for a wide class of the ANNs and requires no high development effort. The new method was tested on real application examples and has delivered very good results. For the non-adaptive virtual sensors a simple adaptation mechanism was suggested. This technique allows the control of dead-time and time-variant processes in closed loop. Besides, in comparison to other control strategies the comparable results were achieved with smaller development effort
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