Search results for "EXCHANGE"
showing 10 items of 2035 documents
Electrostatic phenomena in ion exchange membranes
1971
Abstract Specific and transport properties of a cation and an anion exchange membrane in Na + and Cl - form respectively have been measured in water and dioxane water mixtures. A greater electrolyte absorption and a lesser specific conductivity and counterion transport number in solvents at higher dioxane content indicate strong electrostatic interactions between fixed groups in the membrane and counterions.
Intellectual Capital – The Key for Sustainable Competitive Advantage for the SME's Sector
2015
Abstract With the adoption of the Lisbon Agenda and its major objective, namely that the EU would become the most dynamic and competitive knowledge based economy in the world, it became clear the Small and Medium Enterprises (SME's) are the especially affected by these plans, because they represent the driving force for the European economy. In this context of creating and maintaining a competitive advantage for the SME's, it is crucial for them to make good use of the intellectual capital of their employees, in an efficient and proficient manner, in order to increase their potential for innovation. The aim of this article is to show, through an original argumentation, based on the analysis…
Determination of the atmospheric precipitation pH value on the basis of the analysis of lichen cationoactive layer constitution
2006
Studies of equilibria and kinetics of the ion exchange process between the surrounding (water solution) and lichens prove that the number of mobile hydrogen ions bonded in lichens depends on the concentration of hydrogen ions in the precipitation with which the lichens are in contact and the type and concentration of other cations contained in the precipitation. The measurement of these values was suggested; as a result, it enabled to determine the pH of precipitation by determination of mobile cations bonded in exposed or naturally grown lichens. The studies were conducted on Hypogymnia physodes lichens.
Economic analysis of the international cooperation to face global environmental problems
2013
Because of the doubts about the effectiveness of the Kyoto Protocol, several scholars have asked whether other types of agreements can be designed to achieve large reductions of GHG emissions. Designing a profitable and stable international environmental agreement (IEA) that deals with the shortcomings of Kyoto-type agreement is the main motivation of this work. One idea would be to focus on technology improvements in order to reduce abatement costs, as this might increase a country's willingness to undertake significant emission reductions. For example, it could be beneficial to supplement a Kyoto-type agreement with technology elements if technological development depends not only on a co…
Reforming the international financial and monetary system: from Keynes to Davidson and Stiglitz
2004
International audience; With the usual debates trumpeting the usual merits of fixed versus flexible exchange rates, or some various incarnations thereof, the authors draw attention to Keynes's original plan for an international clearing union. The paper takes a close look at Joseph Stiglitz's recent suggestions to deal with financial crises along with Paul Davidson's Keynes-Post Keynesian clearinghouse. In the former case, the analysis is left wanting: the author offers nothing more than simple solutions to a system in need of dramatic changes. On the other hand, Davidson's analysis of the current state of affairs requires more than mere "plumbing" and addresses the root causes of the crise…
Pressure-Induced Deformation of Pillar-Type Profiled Membranes and Its Effects on Flow and Mass Transfer
2019
In electro-membrane processes, a pressure difference may arise between solutions flowing in alternate channels. This transmembrane pressure (TMP) causes a deformation of the membranes and of the fluid compartments. This, in turn, affects pressure losses and mass transfer rates with respect to undeformed conditions and may result in uneven flow rate and mass flux distributions. These phenomena were analyzed here for round pillar-type profiled membranes by integrated mechanical and fluid dynamics simulations. The analysis involved three steps: (1) A conservatively large value of TMP was imposed, and mechanical simulations were performed to identify the geometry with the minimum pillar density…
A Study of Osmosis Rate Through Several Proton Conducting Polymer Composite Membranes
2021
Carbon dioxide is typically considered to be a byproduct of various industrial processes that should not be released into the environment due to its nature as a harmful greenhouse gas. One of the more promising ways to dispose of it in an economical and environmentally friendly way is by using it as a raw material in electrochemical synthesis reactors. An important part of such reactors is an ion exchange membrane. In this study the influence of ZrO2 content in SPEEK – ZrO2 composite membranes on rate of osmosis trough them was investigated, with the goal of evaluating ZrO2 as an additive for making ion exchange membranes with fine-tuned osmotic permeability.
Performance analysis of the first Reverse Electrodialysis prototype plant operating with natural brackish water and salt pond brine
2014
Reverse Electrodialysis (RED) has gained a strong interest among the salinity gradient energy technologies during the last years. Recently, notable improvements have been reached in terms of membranes and stack performances using artificial solutions. However, the use of real saline solutions strongly affects the process performance, requiring additional R&D efforts for a successful scale-up of such technology. This work focuses on the experimental campaign performed on the first RED prototype plant fed with real brackish water and saltworks brine. The plant is located within the Ettore e Infersa saltworks in Marsala (TP, South of Italy). It is the final accomplishment of the REAPower proje…
A hierarchical model for novel schemes of electrodialysis desalination
2019
Abstract A new hierarchical model for the electrodialysis (ED) process is presented. The model has been implemented into gPROMs Modelbuilder (PSE), allowing the development of a distributed-parameters simulation tool that combines the effectiveness of a semi-empirical modelling approach to the flexibility of a layered arrangement of modelling scales. Thanks to its structure, the tool makes possible the simulation of many different and complex layouts, requiring only membrane properties as input parameters (e.g. membrane resistance or salt and water permeability). The model has been validated against original experimental data obtained from a lab scale ED test rig. Simulation results concern…
Optimisation analysis of Reverse Electrodialysis systems for power production from concentrated brines
2016
Reverse Electrodialysis (RED) is rapidly growing as technology to produce electric energy by mixing saline solutions with different salinity. Recent developments have shown promising results on real site installations, demonstrating the feasibility of the RED process on the pilot scale. Therefore, further modelling efforts are now needed to optimise the technology, in order to enhance the performance. In this work, an optimisation study for the RED process is presented, taking into account saline waters and concentrated brine as feed streams. The model, which is developed within GAMS environment, predicts the optimal set of process variables that maximise the process yield, as well as the g…