Search results for "teoria"
showing 10 items of 2647 documents
Fiducia e argomentazione. Una prospettiva aristotelica
2012
Heat-transfer performance comparison between overlapped and woven spacers for membrane distillation
2016
Sustainable production of fresh water from seawater desalination is a problem of crucial importance nowadays. Recently, some desalination technologies are taking advantage from the coupling with renewable resources. Among emerging technologies, Membrane Distillation (MD) is considered as one of the most promising as it can be easily powered by solar thermal energy or waste-heat. As an emerging technology, efforts are required to optimize MD unit geometry and operating conditions in order to reduce fresh water production specific cost. Temperature polarization phenomenon is a well-known detrimental effect for the MD process. Spacers are traditionally used to enhance mixing and shrink tempera…
Review of Ángel-Luis Pujante and Keith Gregor, eds. Romeo y Julieta en España: Las versiones neoclásicas. Murcia; Madrid: Universidad de Murcia; Univ…
2019
Review of Ángel-Luis Pujante and Keith Gregor, eds. Romeo y Julieta en España: Las versiones neoclásicas. Murcia; Madrid: Universidad de Murcia; Universidad Complutense de Madrid, 2017
Optimization of net power density in Reverse Electrodialysis
2019
Abstract Reverse Electrodialysis (RED) extracts electrical energy from the salinity difference between two solutions using selective ion exchange membranes. In RED, conditions yielding a large net power density (NPD) are generally desired, due to the still large cost of the membranes. NPD depends on a large number of physical and geometric parameters. Some of these, for example the inlet concentrations of concentrate and diluate, can be regarded as “scenario” variables, imposed by external constraints (e.g., availability) or chosen by different criteria than NPD maximization. Others, namely the thicknesses HCONC, HDIL and the velocities UCONC, UDIL in the concentrate and diluate channels, c…
Density-Functional Theory on Graphs
2021
The principles of density-functional theory are studied for finite lattice systems represented by graphs. Surprisingly, the fundamental Hohenberg–Kohn theorem is found void, in general, while many insights into the topological structure of the density-potential mapping can be won. We give precise conditions for a ground state to be uniquely v-representable and are able to prove that this property holds for almost all densities. A set of examples illustrates the theory and demonstrates the non-convexity of the pure-state constrained-search functional. peerReviewed
Energy harvesting by waste acid/base neutralization via bipolar membrane reverse electrodialysis
2020
Bipolar Membrane Reverse Electrodialysis (BMRED) can be used to produce electricity exploiting acid-base neutralization, thus representing a valuable route in reusing waste streams. The present work investigates the performance of a lab-scale BMRED module under several operating conditions. By feeding the stack with 1 M HCl and NaOH streams, a maximum power density of ~17 W m−2 was obtained at 100 A m−2 with a 10-triplet stack with a flow velocity of 1 cm s−1, while an energy density of ~10 kWh m−3 acid could be extracted by a complete neutralization. Parasitic currents along feed and drain manifolds significantly affected the performance of the stack when equipped with a higher number of t…
A limited feedback scheme based on spatially correlated channels for coordinated multipoint systems
2012
High spectral efficiency can be achieved in the downlink of multi-antenna coordinated multi-point systems provided that the multiuser interference is appropriately managed at the transmitter side. For this sake, downlink channel information needs to be sent back by the users, thus reducing the rate available at the uplink channel. The amount and type of feedback information required has been extensively studied and many limited feedback schemes have been proposed lately. A common pattern to all of them is that achieving low rates of feedback information is possible at the cost of increasing complexity at the user side and, sometimes, assuming that some statistics of the channel are known. I…
Using Activity Theory in Developing Instructional Tools for Project Management Studies
2014
Competence and skills of the project manager are significant to project success. The skills needed in project managers’ work cannot be learned only by reading the books or a lecture hall; one learns them by practice. Therefore, an important challenge for educational institutions is to develop pedagogical practices that allow students to participate in working life projects and to confront real-life problems. Project-based learning (PBL) offers a model that enables students to practice the skills and competences needed in working life projects by utilizing real-world work assignments in time-limited projects. Using PBL method alone does not necessarily guarantee learning result. In order to …
Suomalaisten käsityksiä maatalousmaiseman muutoksesta ja maatalouden ekosysteemipalveluista
2015
Tutkimuksen tarkoituksena on suomalaisten maatalousmaisemaan ja maatalouden ekosysteemipalveluihin liittyvien käsitysten tutkiminen. Maatalousmaisema on Suomessa jatkuvassa muutoksessa, ja maisemaan liittyvät näkemykset ovat usein ristiriidassa keskenään. Suomen ratifioiman eurooppalaisen maisemayleissopimuksen mukaan kansalaisten maisema-arvostuksia tulisi huomioida maisemaa koskevassa suunnittelussa ja päätöksenteossa. Maatalousmaisemaa voidaan lähestyä myös sen tarjoamien ekosysteemipalvelujen eli hyötyjen avulla. Tutkimuksessa tarkastellaan, mitä ekosysteemipalveluja ja minkä verran suomalaiset arvioivat maatalousmaiseman tuottavan. Lisäksi tutkitaan, miten kansalaiset yhtäältä ennakoiv…