3,034 research outputs found
Influence of analysis and design models on minimum weight design
The results of numerical experiments designed to illustrate how the minimum weight design, accuracy, and cost can be influenced by: (1) refinement of the finite element analysis model and associated load path problems, and (2) refinement of the design variable linking model are examined. The numerical experiments range from simple structures where the modelling decisions are relatively obvious and less costly to the more complex structures where such decisions are less obvious and more costly. All numerical experiments used employ the dual formulation in ACCESS-3 computer program. Guidelines are suggested for creating analysis and design models that predict a minimum weight structure with greater accuracy and less cost. These guidelines can be useful in an interactive optimization environment and in the design of heuristic rules for the development of knowledge-based expert optimization systems
Randomness amplification against no-signaling adversaries using two devices
Recently, a physically realistic protocol amplifying the randomness of
Santha-Vazirani sources producing cryptographically secure random bits was
proposed; however for reasons of practical relevance, the crucial question
remained open whether this can be accomplished under the minimal conditions
necessary for the task. Namely, is it possible to achieve randomness
amplification using only two no-signaling components and in a situation where
the violation of a Bell inequality only guarantees that some outcomes of the
device for specific inputs exhibit randomness? Here, we solve this question and
present a device-independent protocol for randomness amplification of
Santha-Vazirani sources using a device consisting of two non-signaling
components. We show that the protocol can amplify any such source that is not
fully deterministic into a fully random source while tolerating a constant
noise rate and prove the composable security of the protocol against general
no-signaling adversaries. Our main innovation is the proof that even the
partial randomness certified by the two-party Bell test (a single input-output
pair () for which the conditional probability
is bounded away from for all no-signaling
strategies that optimally violate the Bell inequality) can be used for
amplification. We introduce the methodology of a partial tomographic procedure
on the empirical statistics obtained in the Bell test that ensures that the
outputs constitute a linear min-entropy source of randomness. As a technical
novelty that may be of independent interest, we prove that the Santha-Vazirani
source satisfies an exponential concentration property given by a recently
discovered generalized Chernoff bound.Comment: 15 pages, 3 figure
Synthesis and characterization of polyurethane microspheres
A novel particle forming polymerization technique for the preparation of
polyurethane microspheres with particle size in the range 0.1-100 micron is
described. The method is general, applicable to wide variety of diols and isocyanates
and is very simple. The key to successful particle forming polymerization is the use
of novel steric stabilizers, such as, a reactive diol containing two primary hydroxyl
groups with a long hydrophobic acrylate ester moiety and an amphiphilic block
copolymer. The effect of various reactiorr variables on the particle forming
polymerization process will be discussed
Observation of numerous E2 mode phonon replicas in the room temperature photoluminescence spectra of ZnO nanowires: Evidence of strong deformation potential electron-phonon coupling
The authors report the observation of numerous (\u3e20)phonon replica peaks in the room temperature photoluminescence spectrum of ZnOnanowires embedded in 50nm diameter pores of an anodic alumina film. The peaks are spaced in energy by ∼54meV, which is the energy of a nonpolar phonon with symmetry E2 in ZnO. These peaks are possibly caused by resonant phonon-assisted decay of photoexcited electrons to an impurity band, followed by radiative recombination. These results suggest that even though ZnO is strongly polar, deformation potential coupling to a nonpolar phonon mode may be stronger than Fröhlich coupling to polar phonon modes
Screening of seaweed extracts against antibiotic resistant post operative infectious pathogens
Fifty five seaweed extracts belonging to 11 species of seaweeds were tested against post operative infectious drug resistant bacteria viz., E. coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Streptococcus pyogens, Staphylococcus aureus. Among the seaweed extracts, the
acetone extracts of Caulerpa cupressoides shows maximum inhibtory activity against E. coli and propanol extracts of Gracilaria edulis shows maximum inhibitory effect against
K. pneumoniae. Acetone extracts of Padina tetrastromatica and Laurencia cruciata show maximum inhibitory activity against P. aeruginosa, butanol extracts of Hypnea musciformis, Caulerpa cupressoides and Chaetomorpha linoides show maximum inhibitory effect against S. aureus
Roughness of Crack Interfaces in Two-Dimensional Beam Lattices
The roughness of crack interfaces is reported in quasistatic fracture, using
an elastic network of beams with random breaking thresholds. For strong
disorders we obtain 0.86(3) for the roughness exponent, a result which is very
different from the minimum energy surface exponent, i.e., the value 2/3. A
cross-over to lower values is observed as the disorder is reduced, the exponent
in these cases being strongly dependent on the disorder.Comment: 9 pages, RevTeX, 3 figure
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