20,637 research outputs found
Physical/chemical closed-loop water-recycling
Water needs, water sources, and means for recycling water are examined in terms appropriate to the water quality requirements of a small crew and spacecraft intended for long duration exploration missions. Inorganic, organic, and biological hazards are estimated for waste water sources. Sensitivities to these hazards for human uses are estimated. The water recycling processes considered are humidity condensation, carbon dioxide reduction, waste oxidation, distillation, reverse osmosis, pervaporation, electrodialysis, ion exchange, carbon sorption, and electrochemical oxidation. Limitations and applications of these processes are evaluated in terms of water quality objectives. Computerized simulation of some of these chemical processes is examined. Recommendations are made for development of new water recycling technology and improvement of existing technology for near term application to life support systems for humans in space. The technological developments are equally applicable to water needs on Earth, in regions where extensive water recycling is needed or where advanced water treatment is essential to meet EPA health standards
A fast algorithm for backbones
A matching algorithm for the identification of backbones in percolation
problems is introduced. Using this procedure, percolation backbones are studied
in two- to five-dimensional systems containing 1.7x10^7 sites, two orders of
magnitude larger than was previously possible using burning algorithms.Comment: 8 pages, 6 .eps figures. Uses epsfig and ijmpc.sty (included). To
appear in Int. J. Mod. Phys.
On Nonconservative Stability Problems of Elastic Systems with Slight Damping
Equilibrium stability of linear two degree of freedom system with slight viscous damping subjected to nonconservative loadin
Statistical Laws and Mechanics of Voronoi Random Lattices
We investigate random lattices where the connectivities are determined by the
Voronoi construction, while the location of the points are the dynamic degrees
of freedom. The Voronoi random lattices with an associated energy are immersed
in a heat bath and investigated using a Monte Carlo simulation algorithm. In
thermodynamic equilibrium we measure coordination number distributions and test
the Aboav-Weaire and Lewis laws.Comment: 14 pages (figures not included), LaTeX, HLRZ-26/9
Recommended from our members
Identification of an interchromosomal compartment by polymerization of nuclear-targeted vimentin
A number of structural and functional subnuclear compartments have been described, including regions
exclusive of chromosomes previously hypothesized to form
a reactive nuclear space. We have now explored this
accessible nuclear space and interchromosomal
nucleoplasmic domains experimentally using Xenopus
vimentin engineered to contain a nuclear localization signal
(NLS-vimentin). In stably transfected human cells
incubated at 37°C, the NLS-vimentin formed a restricted
number of intranuclear speckles. At 28°C, the optimal
temperature for assembly of the amphibian protein, NLSvimentin
progressively extended with time out from the
speckles into strictly orientated intranuclear filamentous
arrays. This enabled us to observe the development of a
system of interconnecting channel-like areas. Quantitative
analysis based on 3-D imaging microscopy revealed that
these arrays were localized almost exclusively outside of
chromosome territories. During mitosis the filaments
disassembled and dispersed throughout the cytoplasm,
while in anaphase-telophase the vimentin was recruited
back into the nucleus and reassembled into filaments at the
chromosome surfaces, in distributions virtually identical to
those observed in the previous interphase. The filaments
also colocalized with specific nuclear RNAs, coiled bodies
and PML bodies, all situated outside of chromosome
territories, thereby interlinking these structures. This
strongly implies that these nuclear entities coexist in the
same interconnected nuclear compartment. The
assembling NLS-vimentin is restricted to and can be used
to delineate, at least in part, the formerly proposed
reticular interchromosomal domain compartment (ICD).
The properties of NLS-vimentin make it an excellent tool
for performing structural and functional studies on this
compartment
Framework for the Integration of Service and Technology Strategies
Organised by: Cranfield UniversityAfter sales service is a highly profitable business for manufacturers of technology-driven products. Due to
this fact competitors want to share in high profit margins. At the same time after sales business has to deal
with an increasing range of variants of products and technologies, shorter life cycles and changing
customer demands. In spite of these manifold challenges, often neither after sales departments are
involved in the early product development stage nor are customer demands and technical parameters
considered in the service development processes entirely. Therefore an integration of service and
technology strategies is necessary. This paper presents a framework for this integration that visualises the
complex interdependencies and interfaces between service as well as product and motor vehicle workshop
technologies.Mori Seiki – The Machine Tool Compan
Stochastic resonance for nonequilibrium systems
Stochastic resonance (SR) is a prominent phenomenon in many natural and engineered noisy systems, whereby the response to a periodic forcing is greatly amplified when the intensity of the noise is tuned to within a specific range of values. We propose here a general mathematical framework based on large deviation theory and, specifically, on the theory of quasipotentials, for describing SR in noisy
N
-dimensional nonequilibrium systems possessing two metastable states and undergoing a periodically modulated forcing. The drift and the volatility fields of the equations of motion can be fairly general, and the competing attractors of the deterministic dynamics and the edge state living on the basin boundary can, in principle, feature chaotic dynamics. Similarly, the perturbation field of the forcing can be fairly general. Our approach is able to recover as special cases the classical results previously presented in the literature for systems obeying detailed balance and allows for expressing the parameters describing SR and the statistics of residence times in the two-state approximation in terms of the unperturbed drift field, the volatility field, and the perturbation field. We clarify which specific properties of the forcing are relevant for amplifying or suppressing SR in a system and classify forcings according to classes of equivalence. Our results indicate a route for a detailed understanding of SR in rather general systems
- …