Search results for "propagation [cosmic radiation]"

SURFACE ROUGHNESS PREDICTION OF ELECTRO-DISCHARGE MACHINED COMPONENTS USING ARTIFICIAL NEURAL NETWORKS

2016

Electro-Discharge machining (EDM) is a thermal process comprising a complex metal removal mechanism, which involves the formation of a plasma channel between the tool and the workpiece electrodes leading to the melting and evaporation of the material to be removed. EDM is considered especially suitable for machining complex contours with high accuracy, as well as for materials that are not amenable to conventional removal methods. However, several phenomena negatively affecting the surface integrity of EDMed workpieces need to be taken into account and studied in order to achieve the optimization of the process. Recently, artificial neural networks (ANN) have emerged as a novel modeling tec…

Rateless Codes Performance Analysis in Correlated Channel Model for GEO Free Space Optics Downlinks

2012

Über die elementarprozesse bei der anionischen polymerisation des styrols in tetrahydropyran (THP)

1972

Kinetische und konduktometrische Messungen am System Polystyrl-Natrium in THP werden mit dem Ziel durchgefuhrt, alle in dem fruher vorgeschlagenen dreiteiligen Reaktionsschema vorkommenden thermodynamischen und kinetischen Parameter zu bestimmen und mit den in anderen Losungsmitteln gefundenen Werten zu vergleichen. Es zeigt sich, das die Geschwindigkeitskonstanten der Monomeraddition an das Kontaktionenpaar, das solvatgetrennte Ionenpaar und das freie Anion, die sich um Grosenordnungen unterscheiden, vom Losungsmittel nur geringfugig beeinflust werden. Der ungewohnlich grose Einflus der Losungsmittel auf die Polymerisationsgeschwindigkeit geschieht durch Verschiebung der Gleichgewichte zwi…

Use of carbon dioxide enrichment to obtain adult morphology of grapevinein vitro

1993

A procedure has been developed forin vitro propagation ofVitis vinifera ‘Pinot noir’ from lateral-bud cuttings under high CO2 concentration (1200 µmol mol−1). Because of inhibition of rooting by CO2, this procedure requires a rooting pre-culture of explants on medium with sucrose before the CO2-enriched culture on sucrose-free medium. Shoot growth was enhanced by CO2 enrichment as a result of both a higher rate of leaf production and greater internode elongation. Leaf expansion and tendril growth were promoted and better rooting was obtained. The more significant effect of CO2 enrichment was to promote adult morphology with, in particular, the tendril pattern. Thus, for the first time, grap…

Clustering-based robust three-dimensional phase unwrapping algorithm

2010

Relatively recent techniques that produce phase volumes have motivated the study of three-dimensional (3D) unwrapping algorithms that inherently incorporate the third dimension into the process. We propose a novel 3D unwrapping algorithm that can be considered to be a generalization of the minimum spanning tree (MST) approach. The technique combines characteristics of some of the most robust existing methods: it uses a quality map to guide the unwrapping process, a region growing mechanism to progressively unwrap the signal, and also cut surfaces to avoid error propagation. The approach has been evaluated in the context of noncontact measurement of dynamic objects, suggesting a better perfo…

Testing experimental designs in liquid chromatography (II): Influence of the design geometry on the prediction performance of retention models.

2021

Abstract In liquid chromatography, the reliability of predictions carried out with retention models depends critically on the quality of the training experimental design. The search of the best design is more complex when gradient runs are used instead of isocratic experiments. In Part I of this work (JCA 1624 (2020) 461180), a general methodology based on the error propagation theory was developed and validated for assessing the quality of training designs involving gradients. The treatment relates the mathematical properties of a retention model with the geometry of the training designs and their subsequent predictions. In that work, only five usual designs were considered. Part II invest…

Computer-Aided Diagnosis System with Backpropagation Artificial Neural Network—Improving Human Readers Performance

2016

This article presents the results of a study into possibility of artificial neural networks (ANNs) to classify cancer changes in mammographic images. Today’s Computer-Aided Detection (CAD) systems cannot detect 100 % of pathological changes. One of the properties of an ANN is generalized information —it can identify not only learned data but also data that is similar to training set. The combination of CAD and ANN could give better result and help radiologists to take the right decision.

Modeling of neuron-astrocyte interaction : application to signal and image processing

2022

The introduction of the tripartite synapse and the discovery of calcium wave propagation motivated our research to explore the potential of astrocytes as active components in brain circuits. For decades, astrocytes have been considered passive cells whose primary function is metabolic and structural support to neurons; however, recent physiological measurements suggest that astrocytes modulate neural communication, strengthen synaptic efficacy, enhance synchronization, and promote homeostasis. Inspired by these biological functions, this research aimed to implement astrocytes in artificial spiking networks for deep learning applications. First, we modeled the biological interaction between …

Noise contribution to resonance phenomena and information propagation in non linear electronic networks

2015

This manuscript presents research aiming to show possible positive effects of deterministic and stochastic perturbations on the responses of different nonlinear systems. To that end, both numerical and experimental studies were carried out on two kinds of structures : an elementary electronic FitzHugh-Nagumo oscillator and an electrical line developed by resistively coupling 45 elementary cells. In the first section, the elementary cell characterization was undertaken in a deterministic regime. In the presence of a bichromatic stimulus, it is shown that when the low frequency component is subthreshold, its detection can be maximized for an optimal magnitude of the second component thanks to…

Universal charts for optical difference frequency generation in the terahertz domain

2010

We present a universal and rigorous approach to study difference frequency generation in the terahertz domain, keeping the number of degrees of freedom to a minimum, through the definition of a suitable figure of merit. The proposed method relies on suitably normalized charts, that enable to predict the optical-to-terahertz conversion efficiency of any system based on wave propagation in quadratic nonlinear materials. The predictions of our approach are found to be in good agreement with the best experimental results reported to date, enabling also to estimate the d22 nonlinear coefficient of high quality GaSe.