Search results for "lcsh:Computer engineering. Computer hardware"
showing 10 items of 94 documents
Nanostructured Electrochemical Devices for Sensing, Energy Conversion and Storage
2016
Nanostructured materials are attracting growing interest for improving performance of devices and systems of large technological interest. In this work, the principal results about the use of nanostructured materials in the field of electrochemical energy storage, electrochemical water splitting, and electrochemical sensing are presented. Nanostructures were fabricated with two different techniques. One of these was the electrodeposition of the desired material inside the channels of a porous support acting as template. The other one was based on displacement reaction induced by galvanic contact between metals with different electrochemical nobility. In the present work, a commercial polyca…
Poly lactic acid based scaffolds for vascular tissue engineering
2012
A critical obstacle encountered by tissue engineering is the inability to maintain large masses of living cells upon transfer from the in vitro culture conditions to host in vivo. Capillaries, and the vascular system, are required to supply essential nutrients, including oxygen, remove waste products and provide a biochemical communication "highway". The successful use of tissue-engineered constructs is currently limited to thin or avascular tissues, such as skin or cartilage, for which post-implantation neovascularisation from the host is sufficient to meet the demand for oxygen and nutrients. To succeed in the application of tissue engineering for bigger tissues, such as bone or muscle, t…
Particle distribution in unbaffled stirred vessels
2017
The present work is devoted to providing an insight into the solid-particle distribution within top-covered unbaffled stirred tanks via purposely collected local experimental data. Experiments were carried out on a lab- scale unbaffled stirred tank by making use of a recently introduced technique named Laser Sheet Image Analysis (LSIA). In its original formulation, the technique includes an image post-processing procedure to delete reflection effects on results. In the framework of the present work, a method combining the use of purposely produced fluorescent particles and a suitable camera high pass filter was devised and presented. Results collected with (new method) and without (old fash…
Adaptive Type-2 Fuzzy Logic Control of Non-Linear Processes
2011
The main objective of this study is to provide a valid and effective approach for the design and development of an adaptive type-2 fuzzy controller (AT2FLC), based on the analysis of the nonlinear process dynamics and the use of an ANFIS technique for the optimization of the controller. The performance of the obtained AT2FLC, characterized by a few number of rules, is higher than the performance of a traditional type-2 fuzzy controller with a larger rule base. The proposed controller is particurarly suitable for the control of processes characterized by uncertainty and time varying parameters.
Experimental analysis of a continuously operated reverse electrodialysis unit fed with wastewaters
2017
Reverse Electrodialysis (RED) is one of the most promising technologies to convert salinity gradient chemical energy into electricity. RED units are traditionally operated with natural streams as river water and seawater thereby limiting the spread of the technology in sites far from coastal areas. Aim of the present work is that of exploring and expanding feed possibilities for RED systems by employing waste streams. Thus, an experimental study was performed by testing, for the first time, a Reverse Electrodialysis (RED) unit fed with a high salinity wastewater originated in a fish canning factory, and a low salinity wastewater from a sewage treatment plant. Uninterrupted, long duration ex…
CFD Simulation of Mass Transfer Phenomena in Spacer Filled Channels for Reverse Electrodialysis Applications
2013
Salinity Gradient Power via Reverse Electrodialysis is a topic of primary importance nowadays. It allows getting energy from the “controlled” mixing of solutions at different salt concentration. The performance of this technology depends on many factors such as: components properties (i.e. membranes, spacers, electrodes), stack geometry, operating conditions and feeds features. Concentration polarization phenomena may significantly affect the actual membrane potential, thus reducing the gross power produced. On the other hand, C-polarization phenomena may significantly be reduced by suitably choosing the hydrodynamic regime within the stack. Such a choice may in turn significantly require h…
Utilization of Reverse Electrodialysis Processes for the Abatement of Pollutants in Water
2014
The simultaneous generation of electric energy and th e treatment of waters contaminated by Cr(VI) was carried out by reverse electrodialysis processes using salinity gradients. The effect on the process of the nature of the cathode was investigated.
Dense Solid-Liquid Suspensions in Top-Covered Unbaffled Stirred Vessels
2011
In the present work solids suspension is investigated in an unbaffled tank stirred by a Rushton turbine and provided with a top-cover in order to avoid the formation of the well known central vortex. The data obtained are compared with those pertaining baffled stirred tanks via comparison with the well known Zwietering’s correlation. The dependence of Njs on particle concentration is found to be similar to that well established for baffled vessels, while, as a difference from the latter, Njs is found to decrease when liquid viscosity increases. Results also show that Njs is substantially independent of particle size, a feature that may advice the adoption of unbaffled tanks when large heavy…
CFD Simulation of Solid Liquid Suspensions in Baffled Stirred Vessels Below Complete Suspension Speed
2011
Suspension of solid particles into liquids within stirred vessels is a complex phenomenon encountered in several industrial applications. Most researchers have focused their attention on the assessment of the minimum impeller speed (Njs) able to guarantee the suspension of all particles. Actually, in a number of industrial cases an impeller speed N lower than Njs is chosen as typical operating condition (Oldshue, 1983) as the resulting energy savings well counterbalance the loss of active interfacial area. Therefore, the assessment of the amount of unsuspended particles at any given impeller speed represents the key to quantify the economical advantage/disadvantage of adopting an impeller s…
Measurements of Njs and Power Requirements in Unbaffled Bioslurry Reactors
2012
The remediation of urban/industrial polluted lands is a topic of crucial importance nowadays. Bioremediation techniques are widely employed to remove organic pollutants from contaminated soils because of their simplicity and cheapness. The bioslurry reactors mechanically agitated by stirrers represent one of the most promising bioremediation techniques. In the present work an unbaffled stirred vessel filled with solids and water is experimentally investigated from a fluid dynamic point of view. Air presence within the tank is guaranteed by the central vortex formation (typical occurrence concerning stirred vessels unprovided with baffles) instead of an intrinsically more expensive insufflat…