1,431 research outputs found

    Molecular collisions. 16: Comparison of GPS with classical trajectory calculations of rotational inelasticity for the Ar-N2 system

    Get PDF
    Comparison of generalized phase shift treatment with classical trajectory calculations of rotational inelasticity cross sections of Ar-N2 scatterin

    Scaling of the Hysteresis Loop in Two-dimensional Solidification

    Get PDF
    The first order phase transitions between a two-dimensional (2d) gas and the 2d solid of the first monolayer have been studied for the noble gases Ar, Kr and Xe on a NaCl(100) surface in quasi-equilibrium with the three-dimensional gas phase. Using linear temperature ramps, we show that the widths of the hysteresis loops of these transitions as a function of the heating rate, r, scales with a power law r^alpha with alpha between 0.4 and 0.5 depending on the system. The hysteresis loops for different heating rates are similar. The island area of the condensed layer was found to grow initially with a t^4 time dependence. These results are in agreement with theory, which predicts alpha = 0.5 and hysteresis loop similarity.Comment: 4 pages, 5 figures, Revte

    The Dynamic Fault Tree Rare Event Simulator

    Get PDF
    The dynamic-fault-tree rare event simulator, DFTRES, is a statistical model checker for dynamic fault trees (DFTs), supporting the analysis of highly dependable systems, e.g. with unavailability or unreliability under 10^(-30). To efficiently estimate such low probabilities, we apply the Path-ZVA algorithm to implement Importance Sampling with minimal user input. Calculation speed is further improved by selective automata composition and bisimulation reduction. DFTRES reads DFTs in the Galileo or JANI textual formats. The tool is written in Java 11 with multi-platform support, and it is released under the GPLv3. In this paper we describe the architecture, setup, and input language of DFTRES, and showcase its accurate estimation of dependability metrics of (resilient) repairable DFTs from the FFORT benchmark suite.</p

    Identifying the employment and vocational rehabilitation concerns of people with traditional and emerging disabilities

    Get PDF
    This is the published version, also found here: http://www.iospress.nl/journal/journal-of-vocational-rehabilitation

    Human-Robot Team Interaction Through Wearable Haptics for Cooperative Manipulation

    Get PDF
    The interaction of robot teams and single human in teleoperation scenarios is beneficial in cooperative tasks, for example the manipulation of heavy and large objects in remote or dangerous environments. The main control challenge of the interaction is its asymmetry, arising because robot teams have a relatively high number of controllable degrees of freedom compared to the human operator. Therefore, we propose a control scheme that establishes the interaction on spaces of reduced dimensionality taking into account the low number of human command and feedback signals imposed by haptic devices. We evaluate the suitability of wearable haptic fingertip devices for multi-contact teleoperation in a user study. The results show that the proposed control approach is appropriate for human-robot team interaction and that the wearable haptic fingertip devices provide suitable assistance in cooperative manipulation tasks

    Quantitative study of molecular N_2 trapped in disordered GaN:O films

    Full text link
    The structure of disordered GaN:O films grown by ion-assisted deposition is investigated using x-ray absorption near-edge spectroscopy and Raman spectroscopy. It is found that between 4 and 21 % of the nitrogen in the films is in the form of molecular N_2 that interacts only weakly with the surrounding matrix. The anion to cation ratio in the GaN:O host remains close to unity, and there is a close correlation between the N_2 fraction, the level of oxygen impurities, and the absence of short-range order in the GaN:O matrix.Comment: 5 pages, 3 figure

    Numerical Prediction and Validation of Suspension Flows and its Erosive Effect

    Get PDF
    Erosive wear occurs in many fields of materials handling technology; e.g., during transportation of bulk materials or suspensions, when particles collide with the walls of material handling components such as ducts or pumps. The severity of wear is closely determined by both, component materials and the flow conditions in the medium. Hence a prediction of the wear needs a combination of Computational Fluid Dynamics (CFD) and a Finite Element Method (FEM) that offers realistic simulation of erosion in materials handling components. This paper presents an approach to calculate particle trajectories of a suspension flow. The particle trajectories of a suspension flow are simulated using CFD and experimentally validated. The presented results are part of a project attributed to the VDMA Pumps + Systems which includes the erosion simulation using FEM [1]. The presented approach contributes to the pre-development of material handling components such as pumps and offers valuable assistance to manufactures. This allows a time- and costefficient development of wear-resistant components

    De novo Renal Transplantation after Kaposi Sarcoma: Favorable Outcome in a Patient Receiving Sirolimus and Mycophenolate-Based Immunosuppression

    Get PDF
    Immunosuppressive treatment increases the risk of infection and malignancy in organ transplant recipients. We report on a 42-year-old male renal transplant recipient who lost his first graft after reduction of immunosuppressive treatment due to Kaposi sarcoma and who successfully underwent a second renal transplant 10 years later. The patient's current treatment consists of low-dose prednisone, and the two antiproliferative immunosuppressants mycophenolate mofetil and rapamycin. 4.5 years after his second transplant, the serum creatinine is 1 mg/dl and the patient has no signs of recurrent disease

    Elucidation of Beta-Oxidation Pathways in Ralstonia Eutropha H16 by Examination of Global Gene Expression

    Get PDF
    Ralstonia eutropha H16 is capable of growth and polyhydroxyalkanoate production on plant oils and fatty acids. However, little is known about the triacylglycerol and fatty acid degradation pathways of this bacterium. We compare whole-cell gene expression levels of R. eutropha H16 during growth and polyhydroxyalkanoate production on trioleate and fructose. Trioleate is a triacylglycerol that serves as a model for plant oils. Among the genes of note, two potential fatty acid β-oxidation operons and two putative lipase genes were shown to be upregulated in trioleate cultures. The genes of the glyoxylate bypass also exhibit increased expression during growth on trioleate. We observed that single β-oxidation operon deletion mutants of R. eutropha could grow using palm oil or crude palm kernel oil as the sole carbon source, regardless of which operon was present in the genome, but a double mutant was unable to grow under these conditions. A lipase deletion mutant did not exhibit a growth defect in emulsified oil cultures but did exhibit a phenotype in cultures containing nonemulsified oil. Mutants of the glyoxylate shunt gene for isocitrate lyase were able to grow in the presence of oils, while a malate synthase (aceB) deletion mutant grew more slowly than wild type. Gene expression under polyhydroxyalkanoate storage conditions was also examined. Many findings of this analysis confirm results from previous studies by our group and others. This work represents the first examination of global gene expression involving triacylglycerol and fatty acid catabolism genes in R. eutropha.Malaysia-MIT Biotechnology Partnership Programm
    • …
    corecore