Search results for " packing"
showing 10 items of 99 documents
Musìta. Un oggetto inebriante
2015
Dal Rinascimento in poi – che ci piaccia o no – l’Italia ha cessato la sua funzione di faro culturale dell’Occidente. Negli ultimi tempi, in seguito alla crisi economica che ancora ci attanaglia, le cose sono precipitate verso un basso, ben al di là del fondo, nel quale appena trent’anni fa nessuno avrebbe mai immaginato di scavare. Eppure, nel mondo, si riconoscono all’Italia tre primati, nel design, nella moda e nel cibo: le tre “A” italiane (Arredamento, Abbigliamento, Agro-alimentare) ovvero le tre “F” inglesi (Furniture, Fashion, Food). In particolare, in Sicilia, nonostante l’esportazione di un Versace e di ½ Dolce & Gabbana (per quanto riguarda la moda) e di una millenaria cultura ma…
Qualitative characterisation of effective interactions of charged spheres on different levels of organisation using Alexander’s renormalised charge a…
2005
Abstract Effective interactions are conveniently determined from experimental or numerical data by fitting a Debye–Huckel potential with an effective charge Z ∗ and an effective electrolyte concentration c ∗ as free parameters. In this contribution we numerically solved the Poisson–Boltzmann equation to obtain the so-called renormalised charge Z PBC ∗ . For sufficiently large bare charge Z one finds a saturation of Z ∗ which scales as Z ∗ = A a / λ B , where a is the particle radius, λ B the Bjerrum length and A a proportionality factor of order (8–10). The saturation value increases with increased total micro-ion concentration and shows a shallow minimum as a function of packing fraction. …
Crystal structure of N-(tert-butoxycarbonyl)phenylalanyldehydroalanine isopropyl ester (Boc–Phe–ΔAla–OiPr)
2014
In the crystal structure of the dehydrodipeptide (Boc-Phe-ΔAla-OiPr), the molecule has a trans configuration of the N-methylamide group. Its geometry is different from saturated peptides but is in excellent agreement with other dehydroalanine compounds. In the crystal, an N—H⋯O hydrogen bond links the molecules in a herringbone packing arrangement.
On Utilizing Stochastic Non-linear Fractional Bin Packing to Resolve Distributed Web Crawling
2014
This paper deals with the extremely pertinent problem of web crawling, which is far from trivial considering the magnitude and all-pervasive nature of the World-Wide Web. While numerous AI tools can be used to deal with this task, in this paper we map the problem onto the combinatorially-hard stochastic non-linear fractional knapsack problem, which, in turn, is then solved using Learning Automata (LA). Such LA-based solutions have been recently shown to outperform previous state-of-the-art approaches to resource allocation in Web monitoring. However, the ever growing deployment of distributed systems raises the need for solutions that cope with a distributed setting. In this paper, we prese…
Simulation of fluid-solid coexistence in finite volumes: A method to study the properties of wall-attached crystalline nuclei
2012
The Asakura-Oosawa model for colloid-polymer mixtures is studied by Monte Carlo simulations at densities inside the two-phase coexistence region of fluid and solid. Choosing a geometry where the system is confined between two flat walls, and a wall-colloid potential that leads to incomplete wetting of the crystal at the wall, conditions can be created where a single nanoscopic wall-attached crystalline cluster coexists with fluid in the remainder of the simulation box. Following related ideas that have been useful to study heterogeneous nucleation of liquid droplets at the vapor-liquid coexistence, we estimate the contact angles from observations of the crystalline clusters in thermal equil…
Dual Inequalities for Stabilized Column Generation Revisited
2014
Column generation (CG) models have several advantages over compact formulations: they provide better linear program bounds, may eliminate symmetry, and can hide nonlinearities in their subproblems. However, users also encounter drawbacks in the form of slow convergence, also known as the tailing-off effect, and the oscillation of the dual variables. Among different alternatives for stabilizing the CG process, Ben Amor et al. [Ben Amor H, Desrosiers J, Valério de Carvalho JM (2006) Dual-optimal inequalities for stabilized column generation. Oper. Res. 54(3):454–463] suggest the use of dual-optimal inequalities (DOIs) in the context of cutting stock and bin packing problems. We generalize th…
A Comprehensive Review on Lipid Oxidation in Meat and Meat Products.
2019
Meat and meat products are a fundamental part of the human diet. The protein and vitamin content, as well as essential fatty acids, gives them an appropriate composition to complete the nutritional requirements. However, meat constituents are susceptible to degradation processes. Among them, the most important, after microbial deterioration, are oxidative processes, which affect lipids, pigments, proteins and vitamins. During these reactions a sensory degradation of the product occurs, causing consumer rejection. In addition, there is a nutritional loss that leads to the formation of toxic substances, so the control of oxidative processes is of vital importance for the meat industry. Noneth…
Simulation and theory of fluid demixing and interfacial tension of mixtures of colloids and nonideal polymers.
2005
An extension of the Asakura-Oosawa-Vrij model of hard sphere colloids and non-adsorbing polymers, that takes polymer non-ideality into account through a repulsive stepfunction pair potential between polymers, is studied with grand canonical Monte Carlo simulations and density functional theory. Simulation results validate previous theoretical findings for the shift of the bulk fluid demixing binodal upon increasing strength of polymer-polymer repulsion, promoting the tendency to mix. For increasing strength of the polymer-polymer repulsion, simulation and theory consistently predict the interfacial tension of the free colloidal liquid-gas interface to decrease significantly for fixed colloi…
Chemical Approach to Functional Artificial Opals
2007
Artificial opals are self-assembled colloidal crystals, which consist of a cubic dense packing (fcc) of hard (not film-forming) colloids with diameters ranging from 200 to 900 nm. Because of their periodic nanostructure the assemblies are able to reflect light that matches their periodicity, i.e., UV- to IR-radiation depending on the size of the colloids. Thus, they present a subgroup of 'photonic crystals'. While, originally, the chemistry inside the colloids and the resulting opals was of minor significance, nowadays the chemical variation of opals is becoming more and more important for the preparation of functional and patterned opals. The search for functional opals is, therefore, espe…
Contact formation in random networks of elongated objects
2014
The effect of steric hindrance is an important aspect of granular packings as it gives rise to, e.g., limitations on the densities of ordered and disordered packings, both of which are essentially defined by the geometry of the constituents. Here we focus on random packing of rods via deposition and their distributions of contact number and segment length. Such statistical properties are relevant for mechanical properties of the structures, but the (quite large) steric effects on them have not been addressed in previous studies. We therefore develop a theory that describes the statistical properties of rod packings, while taking into account that the deposited rods cannot overlap and thus i…