5,736 research outputs found
Page composer to translate binary electrical data to optical form
Composer converts binary data to optical form for storage as hologram. Device consists of an array of deformable metal membranes controlled by MOSFET's. Device is fast, produces high contrast ratios, does not degrade with extended use, and can be addressed from diverse angles
Numerical optimization design of advanced transonic wing configurations
A computationally efficient and versatile technique for use in the design of advanced transonic wing configurations has been developed. A reliable and fast transonic wing flow-field analysis program, TWING, has been coupled with a modified quasi-Newton method, unconstrained optimization algorithm, QNMDIF, to create a new design tool. Fully three-dimensional wing designs utilizing both specified wing pressure distributions and drag-to-lift ration minimization as design objectives are demonstrated. Because of the high computational efficiency of each of the components of the design code, in particular the vectorization of TWING and the high speed of the Cray X-MP vector computer, the computer time required for a typical wing design is reduced by approximately an order of magnitude over previous methods. In the results presented here, this computed wave drag has been used as the quantity to be optimized (minimized) with great success, yielding wing designs with nearly shock-free (zero wave drag) pressure distributions and very reasonable wing section shapes
Functional models for large-scale gene regulation networks: realism and fiction
High-throughput experiments are shedding light on the topology of large
regulatory networks and at the same time their functional states, namely the
states of activation of the nodes (for example transcript or protein levels) in
different conditions, times, environments. We now possess a certain amount of
information about these two levels of description, stored in libraries,
databases and ontologies. A current challenge is to bridge the gap between
topology and function, i.e. developing quantitative models aimed at
characterizing the expression patterns of large sets of genes. However,
approaches that work well for small networks become impossible to master at
large scales, mainly because parameters proliferate. In this review we discuss
the state of the art of large-scale functional network models, addressing the
issue of what can be considered as realistic and what the main limitations may
be. We also show some directions for future work, trying to set the goals that
future models should try to achieve. Finally, we will emphasize the possible
benefits in the understanding of biological mechanisms underlying complex
multifactorial diseases, and in the development of novel strategies for the
description and the treatment of such pathologies.Comment: to appear on Mol. BioSyst. 200
11th European Headache Federation Congress jointly with 31st Congress of the Italian Society for the Study of Headaches : Rome, Italy. 01-03 December 2017
. Aims of the study were explore the relationship between peripheral chromatic and central visual dysfunction evaluating also the presence of functional receptor impairment in patients with migraine, with and without aura examined interictally
Influence of interface potential on the effective mass in Ge nanostructures
The role of the interface potential on the effective mass of charge carriers
is elucidated in this work. We develop a new theoretical formalism using a
spatially dependent effective mass that is related to the magnitude of the
interface potential. Using this formalism we studied Ge quantum dots (QDs)
formed by plasma enhanced chemical vapour deposition (PECVD) and co-sputtering
(sputter). These samples allowed us to isolate important consequences arising
from differences in the interface potential. We found that for a higher
interface potential, as in the case of PECVD QDs, there is a larger reduction
in the effective mass, which increases the confinement energy with respect to
the sputter sample. We further understood the action of O interface states by
comparing our results with Ge QDs grown by molecular beam epitaxy. It is found
that the O states can suppress the influence of the interface potential. From
our theoretical formalism we determine the length scale over which the
interface potential influences the effective mass
An experimental set-up for cyclic loading of concrete
Innovative cementitious composite materials are drawing considerable interest due to their substantially improved mechanical properties as compared to ordinary cement-based materials. Their enhanced ductility is promising and particularly suited to structural applications under severe dynamic loading conditions. Cyclic response is essential to understand the effects of loading and unloading on the material, as well as to understanding how it behaves in the transition from tension to compression. It is also fundamental to identify its properties in terms of energy dissipation and strain-rate sensitivity. This paper presents the first part of an ongoing research project which aims to develop the constitutive relationship in innovative cementitious composites and its numerical implementation. Results from this research will facilitate the investigation of the ductility and durability of existing buildings. In this paper, an experimental set-up for uniaxial cyclic loading is described. It was developed to study reversed cyclic compression/tension loadings of innovative cementitious composites. To set the cyclic loading process, cylindrical specimens of concrete were tested. All the tests were performed on a Zwick testing machine with 50 kN load cell. The machine was customised with accessories specifically designed to meet test requirements, avoiding instability and bending moments during the alternating phases of uniaxial compression and tension. Strain gauges were used to measure lateral deformations. The customized machine has shown good performance so far. In order to test specimens with a higher number of cycles and a higher loading rate, improvements to the machine are currently under development. These tests will allow greater insight into the ductility of innovative cementitious composite materials
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