1,441 research outputs found
Molecular collisions. 16: Comparison of GPS with classical trajectory calculations of rotational inelasticity for the Ar-N2 system
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
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
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
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
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
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
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
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
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
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