860 research outputs found
Multi-agent system for dynamic manufacturing system optimization
This paper deals with the application of multi-agent system concept for optimization of dynamic uncertain process. These problems are known to have a computationally demanding objective function, which could turn to be infeasible when large problems are considered. Therefore, fast approximations to the objective function are required. This paper employs bundle of intelligent systems algorithms tied together in a multi-agent system. In order to demonstrate the system, a metal reheat furnace scheduling problem is adopted for highly demanded optimization problem. The proposed multi-agent approach has been evaluated for different settings of the reheat furnace scheduling problem. Particle Swarm Optimization, Genetic Algorithm with different classic and advanced versions: GA with chromosome differentiation, Age GA, and Sexual GA, and finally a Mimetic GA, which is based on combining the GA as a global optimizer and the PSO as a local optimizer. Experimentation has been performed to validate the multi-agent system on the reheat furnace scheduling problem
Color Stability of Elastomers for Maxillofacial Appliances
The color stability of polyvinyl chloride, polyurethane, and silicone polymers for maxillofacial applications was determined after accelerated aging using reflectance spectrophotometry. On the basis of color stability after accelerated aging, and ease of processing, several silicone materials were the most promising.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67056/2/10.1177_00220345780570090401.pd
Exposure of high-temperature alloys in carbonaceous gas atmospheres
Light and scanning electron microscopy were used to evaluate changes resulting from exposure of eight commercial high temperature alloys in carbonaceous atmospheres. Samples were exposed in CO, CH, or CO/CH mixtures up to 900C and 6.2 MPa. All alloys were actively attacked. Surface finish and preoxidation influenced the extent of corrosion. Reduction of NiO, giving a high surface concentration of Ni, promoted catalytic decomposition of CH. Further work is indicated before the performance of these alloys may be ranked with confidence. (auth
Can Bonefish (Albula spp.) be used as a model species for integrating the management of tropical flats environments? [abstract of poster presentation]
A higher order control volume based finite element method to prodict the deformation of heterogeneous materials
Materials with obvious internal structure can exhibit behaviour, under loading, that cannot be described by classical elasticity. It is therefore important to develop computational tools incorporating appropriate constitutive theories that can capture their unconventional behaviour. One such theory is micropolar elasticity. This paper presents a linear strain control volume finite element formulation incorporating micropolar elasticity. Verification results from a micropolar element patch test as well as convergence results for a stress concentration problem are included. The element will be shown to pass the patch test and also exhibit accuracy that is at least equivalent to its finite element counterpart
Color Stability of a Pigmented Elastomer for Maxillofacial Appliances
The color stability of a series of eleven maxillofacial pigments was determined after accelerated aging using reflection spectrophotometry. The results indicate that seven of the pigments demonstrated good to excellent color stability, while four of the pigments were less promising for clinical use.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67027/2/10.1177_00220345790580050301.pd
Helical distribution of the bacterial chemoreceptor via colocalization with the Sec protein translocation machinery
In Escherichia coli, chemoreceptor clustering at a cell pole seems critical for signal amplification and adaptation. However, little is known about the mechanism of localization itself. Here we examined whether the aspartate chemoreceptor (Tar) is inserted directly into the polar membrane by using its fusion to green fluorescent protein (GFP). After induction of Tar–GFP, fluorescent spots first appeared in lateral membrane regions, and later cell poles became predominantly fluorescent. Unexpectedly, Tar–GFP showed a helical arrangement in lateral regions, which was more apparent when a Tar–GFP derivative with two cysteine residues in the periplasmic domain was cross-linked to form higher oligomers. Moreover, similar distribution was observed even when the cytoplasmic domain of the double cysteine Tar–GFP mutant was replaced by that of the kinase EnvZ, which does not localize to a pole. Observation of GFP–SecE and a translocation-defective MalE–GFP mutant, as well as indirect immunofluorescence microscopy on SecG, suggested that the general protein translocation machinery (Sec) itself is arranged into a helical array, with which Tar is transiently associated. The Sec coil appeared distinct from the MreB coil, an actin-like cytoskeleton. These findings will shed new light on the mechanisms underlying spatial organization of membrane proteins in E. coli
Low noise amplication of an optically carried microwave signal: application to atom interferometry
In this paper, we report a new scheme to amplify a microwave signal carried
on a laser light at =852nm. The amplification is done via a
semiconductor tapered amplifier and this scheme is used to drive stimulated
Raman transitions in an atom interferometer. Sideband generation in the
amplifier, due to self-phase and amplitude modulation, is investigated and
characterized. We also demonstrate that the amplifier does not induce any
significant phase-noise on the beating signal. Finally, the degradation of the
performances of the interferometer due to the amplification process is shown to
be negligible
Do bonefish (Albula vulpes) use mangroves for protection from predators following catch-and-release angling?
Low-energy excitations in the three-dimensional random-field Ising model
The random-field Ising model (RFIM), one of the basic models for quenched
disorder, can be studied numerically with the help of efficient ground-state
algorithms. In this study, we extend these algorithm by various methods in
order to analyze low-energy excitations for the three-dimensional RFIM with
Gaussian distributed disorder that appear in the form of clusters of connected
spins. We analyze several properties of these clusters. Our results support the
validity of the droplet-model description for the RFIM.Comment: 10 pages, 9 figure
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