Search results for "diffusion"

Water Fluxes in Polymeric Membranes for Desalination via Membrane Distillation

2010

Membrane distillation is an emerging technique for seawater desalination. Hydrophobic polymeric membranes are used to separate the solute‐free water vapour from the hot solution. Vapour fluxes of commercial polymeric membranes were measured in various conditions, i.e. natural and forced convection and vacuum. Vapour fluxes were also predicted with models and compared with experimentals. Higher fluxes were recorded in vacuum conditions.

Modeling of surface vs. bulk ionic conductivity in fixed charge membranes

2003

A two-region model for describing the conductivity of porous fixed charge membranes is proposed. In the surface region, the conductivity is due to the mobile positive ions (counterions) around the negative fixed charges. In the pore center region, the conductive properties resemble those of the external electrolyte solution because the fixed charges are assumed to be effectively neutralized by the counterions in the surface region. Activation energies and surface diffusion coefficients are estimated by assuming that the counterion jump from a fixed charge group is the rate limiting process for surface transport. The barrier energy for this jump is calculated using a simple electrostatic mod…

Novel method for determination of tritium depth profiles in metallic samples

2019

Tritium accumulation in fusion reactor materials is considered a serious radiological issue, therefore a lot of effort has been concentrated on the development of radiometric techniques. A novel method, based on gradual dissolution, for the determination of the total tritium content and its depth profiles in metallic samples is demonstrated. This method allows for the measurement of tritium in metallic samples after their exposure to a hydrogen and tritium mixture, tritium containing plasma or after irradiation with neutrons resulting in tritium formation. In this method, successive layers of metal are removed using an appropriate etching agent in the controlled regime and the amount of evo…

Modeling of intracellular transport in realistic cell geometries

2018

The transport of molecules inside cells is a complex process, the characterization of which is important to gain full understanding of cellular processes. Understanding of intracellular transport is also important for medical applications, for example when analyzing transport of medicine inside cells. The intracellular environment is very complex, and at least the most crucial parts of this complexity must be accounted for to solve transport problems in cells. In this thesis the results of studies in modeling intracellular transport are presented. The aim of the work was to model intracellular transport of proteins and viral capsids in realistic cell environments. To this end, microscopic m…

Adopting sustainable irrigation technologies in Italy: a study on the determinants of inter- and intra-farm diffusion

2023

This paper analyses the drivers for adopting irrigation systems with water conservation and saving technologies (WCSTs) by Italian farmers. The agricultural sector in Italy, like in other Mediterranean countries, suffers from water scarcity and water endowment variability. Water resources play a decisive role in agricultural production and in implementing large-scale WCSTs capable of improving the resilience of the whole agricultural sector. This study uses a microeconomic panel data approach to estimate farmers' decisions in adopting (inter-farm) sustainable irrigation technologies and assesses the intensity of (intra-farm) water-saving practices. Our analysis identifies the main determina…

Joves Investigadors i Difusió Arqueològica. Primer Seminari d’Arqueologia (UVEG)

2012

Report of workshop activities.

Knowledge discovery using diffusion maps

2013

Intranuclear dynamics in parvovirus infection

2009

Big high-dimensional data analysis with diffusion maps

2013

High-dimensional Big Data processing with dictionary learning and diffusion maps

2015

Algorithms for modern Big Data analysis deal with both massive amount of sam- ples and a large number of features (high-dimension). One way to cope with these challenges is to assume and discover the existence of localization in the data by uncovering its intrinsic geometry. This approach suggests that different data segments can be analyzed separately and then unified in order to gain an understanding of the whole phenomenon. Methods that utilize efficiently local- ized data are attractive for high-dimensional big data analysis, because they can be parallelized, and thus the computational resources, which are needed for their utilization, are realistic and affordable. These methods can explo…