Search results for " layer"
showing 10 items of 1022 documents
CHARACTERIZATION AND DEVELOPMENT OF DIFFERENT METHODS TO EXTEND THE SHELF LIFE OF FRESH-CUT FRUIT
2017
La frutta di IV gamma è un prodotto altamente deperibile, con una shelf-life molto corta (5-7 giorni) influenzata dalle numerose variabili che entrano in gioco accelerando la senescenza del prodotto. Il suo alto valore aggiunto può giustificare l’utilizzo di soluzioni di conservazione più o meno costose. I metodi attualmente esistenti sono numerosi, spaziano dal dipping in sostanze naturali o sintetiche, all’utilizzo di packaging attivi, all’impiego di atmosfere modificate, ecc. Queste metodiche di conservazione incidono in maniera diversa sui costi finali del prodotto ma soprattutto sulla conservazione dello stesso e sul mantenimento della sua qualità lungo tutto il periodo di shelf-life. …
Existence and Singularities for the Prandtl Boundary Layer Equations
2000
Prandtl's boundary layer equations, first formulated in 1904, resolve the differences between the viscous and inviscid description of fluid flows. This paper presents a review of mathematical results, both analytic and computational, on the unsteady boundary layer equations. This includes a review of the derivation and basic properties of the equations, singularity formation, well-posedness results, and infinite Reynolds number limits.
Gradient elasticity and nonstandard boundary conditions
2003
Abstract Gradient elasticity for a second gradient model is addressed within a suitable thermodynamic framework apt to account for nonlocality. The pertinent thermodynamic restrictions upon the gradient constitutive equations are derived, which are shown to include, besides the field (differential) stress–strain laws, a set of nonstandard boundary conditions. Consistently with the latter thermodynamic requirements, a surface layer with membrane stresses is envisioned in the strained body, which together with the above nonstandard boundary conditions make the body constitutively insulated (i.e. no long distance energy flows out of the boundary surface due to nonlocality). The total strain en…
Study of the Chemical Conversion of Aluminum Alloys by Coupling CFDE and EQCM
2004
The ability of the channel flow double electrode (CFDE) technique and electrochemical quartz crystal microbalance (EQCM) for studying in situ chromate phosphate conversion coating on 5182 aluminum alloys was explored. It was first demonstrated that aqueous Cr(VI) can be analyzed quantitatively with the CFDE technique by reduction into Cr(III) on a graphite electrode. Samples used for EQCM were quartz plated by physical vapor deposition using a 5182 alloy target, allowing thin layers of aluminum alloys with a similar chemical composition to be obtained. EQCM was adapted in order to account for the hydrodynamic conditions in an industrial process, by placing the quartz in a flow cell. In orde…
Marine organisms as source of bioactive molecules applied in restoration projects
2015
Abstract In recent decades research in the conservation and restoration field has provided sustainable alternatives to traditional procedures for cleaning or controlling the microbial colonization of works of art. In the present study, for the first time novel bioactive molecules extracted from marine invertebrate organisms (Anthozoa) were tested instead of chemical compounds for removing protein layers or as a biocide for controlling fungal or bacterial colonization. In particular, Bioactive Molecules with Protease activity (BMP), acting in a temperature range of 4- 30°C, were tested for the hydrolysis of protein layers on laboratory specimens. The cleaning protocol provides a selective pr…
Area‐Selective Atomic Layer Deposition on Functionalized Graphene Prepared by Reversible Laser Oxidation
2022
Publisher Copyright: © 2022 The Authors. Advanced Materials Interfaces published by Wiley-VCH GmbH. Area-selective atomic layer deposition (ALD) is a promising “bottom-up” alternative to current nanopatterning techniques. While it has been successfully implemented in traditional microelectronic processes, selective nucleation of ALD on 2D materials has so far remained an unsolved challenge. In this article, a precise control of the selective deposition of ZnO on graphene at low temperatures (<250 °C) is demonstrated. Maskless femtosecond laser writing is used to locally activate predefined surface areas (down to 300 nm) by functionalizing graphene to achieve excellent ALD selectivity (up to…
MBE growth and properties of low-density InAs/GaAs quantum dot structures.
2011
We present the results of a comprehensive study carried out on morphological, structural and optical properties of InAs/GaAs quantum dot structures grown by Molecular Beam Epitaxy. InAs quantum dots were deposited at low growth rate and high growth temperature and were capped with InGaAs upper confining layers. Owing to these particular design and growth parameters, quantum dot densities are in the order of 4-5x109 cm-2 with emission wavelengths ranging from 1.20 to 1.33 µm at 10 K, features that make these structures interesting for single-photon operation at telecom wavelength. High resolution structural techniques show that In content and composition profiles in the structures depend on …
Bright Retinal Lesions Detection using Color Fundus Images Containing Reflective Features
2009
Recently, the research community has developed many techniques to detect and diagnose diabetic retinopathy with retinal fundus images. This is a necessary step for the implementation of a large scale screening effort in rural areas where ophthalmologists are not available. In the United States of America, the incidence of diabetes is increasing among the young population. Retina fundus images of patients younger than 20 years old present a high amount of reflectance due to the Nerve Fibre Layer (NFL). Generally, the younger the patient the more the reflectance is visible. We are not aware of algorithms able to explicitly deal with this type of artifact.
Multi-layer intrusion detection system with ExtraTrees feature selection, extreme learning machine ensemble, and softmax aggregation
2019
Abstract Recent advances in intrusion detection systems based on machine learning have indeed outperformed other techniques, but struggle with detecting multiple classes of attacks with high accuracy. We propose a method that works in three stages. First, the ExtraTrees classifier is used to select relevant features for each type of attack individually for each (ELM). Then, an ensemble of ELMs is used to detect each type of attack separately. Finally, the results of all ELMs are combined using a softmax layer to refine the results and increase the accuracy further. The intuition behind our system is that multi-class classification is quite difficult compared to binary classification. So, we…
Short term wind speed prediction using Multi Layer Perceptron
2012
Among renewable energy sources wind energy is having an increasing influence on the supply of energy power. However wind energy is not a stationary power, depending on the fluctuations of the wind, so that is necessary to cope with these fluctuations that may cause problems the electricity grid stability. The ability to predict short-term wind speed and consequent production patterns becomes critical for the all the operators of wind energy. This paper studies several configurations of Artificial Neural Networks (ANN), a well-known tool able to estimate wind speed starting from measured data. The presented ANNs, t have been tested through data gathered in the area of Trapani (Sicily). Diffe…