Search results for "medium"
showing 10 items of 3746 documents
The Effect of Mechanocatalytic Pretreatment on the Structure and Depolymerization of Willow
2020
In this study, the effect of a mechanocatalytic pretreatment on the structure of willow and sugar release from pretreated willow was explored. In the mechanocatalytic approach, the pretreatment consists of solvent-free impregnation with sulfuric acid and a mechanical treatment with ball milling. Willow sawdust and pretreated samples were analyzed with field emission scanning electron microscope and X-ray diffraction. The products in the sugar solution were determined as the total reducing sugars with the 3,5-dinitrosalicylic acid method and monosaccharides with capillary electrophoresis. According to the results, milling increased the sugar production, depending on the sulfuric acid load. T…
Quantificazione del merito creditizio e costo del denaro per le imprese italiane: caratteristiche e simulazioni spaziali in Italia
2012
L’economia dei flussi di cassa è il Leitmotiv di questi anni, e il denaro condiziona i comportamenti individuali e collettivi. Economie tradizionalmente solide entrano in crisi se non riscuotono la fiducia dei mercati, e le famiglie, come le imprese, difficilmente riescono a programmare il proprio futuro senza le risorse finanziarie occorrenti per le proprie attività. Nel complesso periodo che stiamo vivendo, è opinione diffusa che l’uscita dalla crisi economica derivi da cambiamenti epocali nell’organizzazione dei sistemi produttivi e finanziari nonché negli stili di vita, rivisitando il significato stesso di sviluppo economico. In tale contesto la marginalità finanziaria, intesa come vant…
Opportunistic Synchronization for Improving IEEE 802.15.4 MAC Performance in Chain Topologies
2010
The most effective solution for energy saving in low-rate wireless sensor networks is maintaining each node in a doze state as long as possible. In order to guarantee network connectivity, the intervals at which the network sensors are turned on and off have to be coordinated. Therefore, synchronization is a very critical function for sensor networks. In this paper, we analyze the IEEE 802.15.4 MAC performance in sensor networks deployed in a chain topology. For this topology, critical inefficiencies can arise in case of multi-hop packet deliveries. We evaluate the impact of different synchronization schemes on the network performance, both in terms of network throughput and in terms of ene…
Shape identification in inverse medium scattering problems with a single far-field pattern
2016
Consider time-harmonic acoustic scattering from a bounded penetrable obstacle $D\subset {\mathbb R}^N$ embedded in a homogeneous background medium. The index of refraction characterizing the material inside $D$ is supposed to be Holder continuous near the corners. If $D\subset {\mathbb R}^2$ is a convex polygon, we prove that its shape and location can be uniquely determined by the far-field pattern incited by a single incident wave at a fixed frequency. In dimensions $N \geq 3$, the uniqueness applies to penetrable scatterers of rectangular type with additional assumptions on the smoothness of the contrast. Our arguments are motivated by recent studies on the absence of nonscattering waven…
Impact of Different Washing Conditions on the Release of Ag Species from Textiles
2016
The paper investigates the Ag release from textiles (socks available in shops, cotton and viscose filled with Ag nanoparticles–AgNPs) into a washing solution under different conditions. The released Ag amount depended on various factors, such as test media (chemical composition, temperature and water volume), metal contents, and textile impregnation conditions. Furthermore, it turned out that the textile type and colour were the main parameters affecting the Ag release. The Ag concentration in the washing solution ranged between 0.015 μg/l and 4.44 μg/l (socks) and between 0.61 μg/l and 103 μg/l (AgNPs–filled cotton). The total Ag percentage released into water during one washing varied con…
Fibre fragment distribution in a single-fibre composite tension test
2001
Abstract Single fibre fragmentation tests are performed for brittle fibres with Weibull strength distribution and different surface treatments. The fragmentation process is modelled and closed-form expressions for break spacing distribution are obtained. The model accounts for the effect of finite fibre length on the initial fragmentation as well as for break interaction on the advanced fragmentation stage. It is assumed that the exclusion zone due to fibre–matrix interface failure and stress recovery in the fibre is linearly dependent on the applied load. This assumption is validated experimentally. The derived theoretical average fragment length dependence on applied load is used to deter…
Zinc Adsorption by Activated Carbon Prepared from Lignocellulosic Waste Biomass
2019
Sawdust was used as a precursor for the production of biomass-based activated carbon. Carbonization and activation are single-stage processes, and steam was used as a physical activation agent at 800 °
STARTUP, INNOVAZIONE E SOCIETA' AGRICOLE
2020
The work aims to identify advantageous solutions for agricultural companies that want to adhere to the discipline provided by the legislator for SMEs by comparing it with the discipline provided for Startups
Electronic polarizability of small metal spheres
1985
We present the results of calculations for the ground-state electron structure, static polarizability, and dynamic response of small metal (jellium) spheres in vacuum or embedded in a dielectric. Fully self-consistent time-dependent density-functional methods are used. In particular, the static and dynamic responses to an incident electric field (dipolar polarizability and photoabsorption) are obtained. The results show substantial deviations from either classical or approximate quantum-mechanical solutions, and provide reference data for simplified treatments. Peer reviewed