Search results for "Fluids"
showing 10 items of 1936 documents
Dynamics of a minimal consumer network with bi -directional influence
2018
Abstract We study the dynamics of a model of interdependent consumer behavior defined by a family of two-dimensional noninvertible maps. This family belongs to a class of coupled logistic maps with different nonlinearity parameters and coupling terms that depend on one variable only. In our companion paper we considered the case of independent consumers as well as the case of uni-directionally connected consumers. The present paper aims at describing the dynamics in the case of a bi-directional connection. In particular, we investigate the bifurcation structure of the parameter plane associated with the strength of coupling between the consumers, focusing on the mechanisms of qualitative tr…
On boundaries of attractors in dynamical systems
2021
Abstract Fractal geometry is one of the beautiful and challenging branches of mathematics. Self similarity is an important property, exhibited by most of the fractals. Several forms of self similarity have been discussed in the literature. Iterated Function System (IFS) is a mathematical scheme to generate fractals. There are several variants of IFSs such as condensation IFS, countable IFS, etc. In this paper, certain properties of self similar sets, using the concept of boundary are discussed. The notion of boundaries like similarity boundary and dynamical boundary are extended to condensation IFSs. The relationships and measure theoretic properties of boundaries in dynamical systems are a…
Non-reflecting boundary conditions for acoustic propagation in ducts with acoustic treatment and mean flow
2011
We consider a time-harmonic acoustic scattering problem in a 2D infinite waveguide with walls covered with an absorbing material, in the presence of a mean flow assumed uniform far from the source. To make this problem suitable for a finite element analysis, the infinite domain is truncated. This paper concerns the derivation of a non-reflecting boundary condition on the artificial boundary by means of a Dirichlet-to-Neumann (DtN) map based on a modal decomposition. Compared with the hard-walled guide case, several difficulties are raised by the presence of both the liner and the mean flow. In particular, acoustic modes are no longer orthogonal and behave asymptotically like the modes of a …
A whey-predominant formula induces fecal microbiota similar to that found in breast-fed infants
2007
To compare the effects of a whey-predominant infant formula and breast milk on the gut microbiota, growth, and tolerance of infants, we conducted an open, prospective, parallel-group study in healthy newborn infants. A total of 60 infants were enrolled, and 55 completed the study. Of the 55 infants, 21 were breast-fed and 34 were fed a whey-predominant study formula that had low phosphate concentration (31 mg/100 kcal), was reduced in protein (1.8 g/100 kcal or 0.43 g/kJ), had lactose as the sole carbohydrate source, and had an amino acid profile and buffering capacity similar to that of human milk. At 30 and 60 days of age, fecal bacterial counts were determined using fluorescence in situ …
Vitamin E as an IgE inhibitor: stability during cold storage of human milk
2008
Human breast milk is recommended as the unique food for neonates based on its known properties. When the production of milk by themother is not suf cient or the mother is not able to feed her child for professional reasons, milk banks or the mothers practice ofcollecting their own milk are the existing alternatives for breast-feeding. In both situations cold storage (refrigeration or freezing) can beused in neonatal units, at home and in human milk banks
Sample pretreatment techniques for oligopeptide analysis from natural sources
2008
The analysis of oligopeptides in samples of food, tissues, and body fluids attracts considerable attention. The complexity of such samples requires efficient sample preparation (i.e., concentration and cleanup) procedures to remove interfering endogenous compounds and inorganic or organic salts. The methods of sample pretreatment that enable effective and selective isolation and/or preconcentration of oligopeptides from complex sample matrices have been reviewed. In each case, examples of application were presented and discussed, taking into account selectivity, enrichment, method automation, cleanup, and environmental aspects of the developed methods.
Gold Nanoparticle-Assisted Virus Formation by Means of the Delivery of an Oncolytic Adenovirus Genome
2020
[EN] Oncolytic adenoviruses are a therapeutic alternative to treat cancer based on their ability to replicate selectively in tumor cells. However, their use is limited mainly by the neutralizing antibody (Nab) immune response that prevents repeated dosing. An alternative to facilitate the DNA access to the tumor even in the presence of anti-viral Nabs could be gold nanoparticles able to transfer DNA molecules. However, the ability of these nanoparticles to carry large DNA molecules, such as an oncolytic adenovirus genome, has not been studied. In this work, gold nanoparticles were functionalized with different amounts of polyethylenimine to transfer in a safe and efficient manner a large on…
The Peregrine soliton in nonlinear fibre optics
2010
International audience; The Peregrine soliton is a localized nonlinear structure predicted to exist over 25 years ago, but not so far experimentally observed in any physical system. It is of fundamental significance because it is localized in both time and space, and because it defines the limit of a wide class of solutions to the nonlinear Schrödinger equation (NLSE). Here, we use an analytic description of NLSE breather propagation to implement experiments in optical fibre generating femtosecond pulses with strong temporal and spatial localization, and near-ideal temporal Peregrine soliton characteristics. In showing that Peregrine soliton characteristics appear with initial conditions th…
Smart structures through nontraditional design of Tuned Mass Damper Inerter for higher control of base isolated systems
2020
Abstract This paper introduces a smart structure design through the definition of an innovative passive control strategy, referred to as New Tuned Mass Damper Inerter (New TMDI), coupled with a base isolation system (BI), to control displacements in base isolated structures under seismic excitations. The herein proposed New TMDI comprises a recently developed nontraditional Tuned Mass Damper (known as New TMD), in which a secondary mass system is connected to the base plate of the BI system by a spring and to the ground by a dashpot, and of an inerter device placed in parallel with the damper. An optimization procedure which minimizes the base displacement variance of the BI system, conside…
Determination of a pre-heating sequence for the DONES Target Assembly
2021
Abstract Within the activities promoted by the EUROfusion consortium in support of the design and construction of the DEMO Oriented NEutron Source (DONES), a mock-up of its Target Assembly (TA), based on the configuration with a “bayonet” Back-Plate (BP) and available at ENEA Brasimone labs, is being adopted for the execution of experimental activities aiming at the validation of specific aspects of the target design. Despite the “integral”-TA concept is the current reference, experimental tests concerning the TA pre-heating phase are not significantly affected by the TA concept and are still representative even though conducted on the bayonet-TA concept. Indeed, the main objective of the p…