An assessment of multibody simulation tools for articulated spacecraft

A survey of multibody simulation codes was conducted in the spring of 1988, to obtain an assessment of the state of the art in multibody simulation codes from the users of the codes. This survey covers the most often used articulated multibody simulation codes in the spacecraft and robotics community. There was no attempt to perform a complete survey of all available multibody codes in all disciplines. Furthermore, this is not an exhaustive evaluation of even robotics and spacecraft multibody simulation codes, as the survey was designed to capture feedback on issues most important to the users of simulation codes. We must keep in mind that the information received was limited and the technical background of the respondents varied greatly. Therefore, only the most often cited observations from the questionnaire are reported here. In this survey, it was found that no one code had both many users (reports) and no limitations. The first section is a report on multibody code applications. Following applications is a discussion of execution time, which is the most troublesome issue for flexible multibody codes. The representation of component flexible bodies, which affects both simulation setup time as well as execution time, is presented next. Following component data preparation, two sections address the accessibility or usability of a code, evaluated by considering its user interface design and examining the overall simulation integrated environment. A summary of user efforts at code verification is reported, before a tabular summary of the questionnaire responses. Finally, some conclusions are drawn

Role of high-spin hyperon resonances in the reaction of γp→K+K+Ξ−\gamma p \to K^+ K^+ \Xi^-

The recent data taken by the CLAS Collaboration at the Thomas Jefferson National Accelerator Facility for the reaction of $\gamma p \to K^+ K^+ \Xi^-$ are reanalyzed within a relativistic meson-exchange model of hadronic interactions. The present model is an extension of the one developed in an earlier work by Nakayama, Oh, and Haberzettl [Phys. Rev. C 74, 035205 (2006)]. In particular, the role of the spin-5/2 and -7/2 hyperon resonances, which were not included in the previous model, is investigated in the present study. It is shown that the contribution of the $\Sigma(2030)$ hyperon having spin-7/2 and positive parity has a key role to bring the model predictions into a fair agreement with the measured data for the $K^+\Xi^-$ invariant mass distribution.Comment: 8 pages, 3 figures, REVTe

Halving the Casimir force with conductive oxides

The possibility to modify the strength of the Casimir effect by tailoring the dielectric functions of the interacting surfaces is regarded as a unique opportunity in the development of Micro- and NanoElectroMechanical Systems. In air, however, one expects that, unless noble metals are used, the electrostatic force arising from trapped charges overcomes the Casimir attraction, leaving no room for exploitation of Casimir force engineering at ambient conditions. Here we show that, in the presence of a conductive oxide, the Casimir force can be the dominant interaction even in air, and that the use of conductive oxides allows one to reduce the Casimir force up to a factor of 2 when compared to noble metals.Comment: modified version, accepted for publication in Phys Rev Let

Exciton transport in thin-film cyanine dye J-aggregates

We present a theoretical model for the study of exciton dynamics in J-aggregated monolayers of fluorescent dyes. The excitonic evolution is described by a Monte-Carlo wave function approach which allows for a unified description of the quantum (ballistic) and classical (diffusive) propagation of an exciton on a lattice in different parameter regimes. The transition between the ballistic and diffusive regime is controlled by static and dynamic disorder. As an example, the model is applied to three cyanine dye J-aggregates: TC, TDBC, and U3. Each of the molecule-specific structure and excitation parameters are estimated using time-dependent density functional theory. The exciton diffusion coefficients are calculated and analyzed for different degrees of film disorder and are correlated to the physical properties and the structural arrangement of molecules in the aggregates. Further, exciton transport is anisotropic and dependent on the initial exciton energy. The upper-bound estimation of the exciton diffusion length in the TDBC thin-film J-aggregate is of the order of hundreds of nanometers, which is in good qualitative agreement with the diffusion length estimated from experiments.Comment: 16 pages, 14 figure

Evaluation of River Health and Water Quantity at the Anseong River, Changwon City, Korea

The paper aims to analyse the degree of river naturality according to the river morphology and the flora at raparian regions on the Anseong River during four seasons. Number of flexion was one at upper and low regions. That of middle region was absent. Bed materials were boulders and gravel in upper region and sand, silt, and clay in middle and low regions. Material of river shore at low channel width was the state of nature without protecting materials at upper region, but that was concreted impervious. Those of middle and upper regions were many artificial levees. The flora on the Anseong River was a total of 61 taxa, including 25 families, 54 species, and 7 varieties. The oxygen demand parameters COD, and BOD were within unacceptable levels at middle and low regions. Many cement blocks were creating instead river grasslands by the Direct stream Rivers Project and wide road construction. This artificial action reduced the waters natural filtration action

Small-for-size liver graft injury-impact on tumor behavior

The success of liver transplantation has led to an ever-increasing demand for liver grafts. Since the first successful living donor liver transplantation, this surgical innovation has been well established in children and has significantly relieved the crisis of donor organ shortage for children. However, the extension of living donor liver transplantation to adult recipients is limited by the graft volume. The major concern of adult-to-adult living donor liver transplantation is the adequate graft that can be harvested from a living donor. Small-for-size graft injury is frequently observed. To develop novel effective treatments attenuating small-for-size liver graft injury during living donor liver transplantation, it is important to explore the precise mechanism of acute phase small-for-size graft damage. Recently, a number of clinical studies and animal experiments have been conducted to investigate the possible key issues on acute phase small-for-size liver graft injury, such as mechanical injury from shear stress, subsequent inflammatory responses, and imbalance of vasoregulatory factors. This review focuses on the mechanism of small-for-size liver graft injury based on the number of clinical and experimental studies. The latest research findings of the significance of acute phase liver graft injury on late phase tumor recurrence and metastasis are also addressed. © 2010 Elsevier Inc. All rights reserved.postprin