Search results for " potential"
showing 10 items of 2713 documents
Analysis of wave energy conversion process
2011
Since wave energy conversion technologies are developing due to the depletion of fossil fuels and due to their hazardous effects on the environment, an important and unexploited source of energy is wave energy. The paper proposes to compare theoretical data obtained using specialized software and data obtained via laboratory measurements using a scale model, regarding the mechanical torque generated at the axis of the electric motor. The data collected represent the kinetic and potential energy, simulating Black Sea waves using an installation proposed to be patented, an installation that converts off-shore wave energy.
The foaming properties of camel and bovine whey: The impact of pH and heat treatment
2018
International audience; he effect of heat treatment (70 degrees C or 90 degrees C for 30 min) on the foaming and interfacial properties of acid and sweet whey obtained from bovine and camel fresh milk was examined. The maximum foamability and foam stability were observed for acid whey when compared to sweet whey for both milks, with higher values for the camel whey. This behavior for acid whey was explained by the proximity of the pI of whey protein (4.9-5.2), where proteins were found to carry the lowest negative charge as confirmed by the zeta potential measurements. Interfacial properties of acid camel whey and acid bovine whey were preserved at air water interface even after a heat trea…
Surface properties of Saccharomyces cerevisiae lees during sparkling wine ageing and their effect on flocculation
2009
Cell surface properties were determined for the first time for lees of Saccharomyces cerevisiae, and they proved to be significantly dependent on the time of sparkling wine ageing on lees. Cell surface hydrophobicity decreased from approximately 44% to 11% of affinity to hexadecane. Electron acceptor capacity (calculated as % affinity to ethyl acetate-% affinity to decane) increased from approximately -27% to 10 % and zeta potential from approximately -4 to 6mV. Mannoproteins are released from the external cell wall layer during the autolytic process, as confirmed by TOF-SIMS analysis of the cell wall chemical composition. This could explain the modifications of lees cell surface properties…
Mathematical modelling of alternating electromagnetic and hydrodynamic fields, induced by bar type conductors in a cylinder
2009
The heating of buildings by ecologically clean and compact local devices is an interesting and actual problem. One of the modern areas of applications developed during last ten years is an effective usage of electrical energy by alternating current to produce heat energy. This work presents the mathematical model of one of such devices. It is a finite cylinder with viscous incompressible liquid and with metal electrodes of the form of bars placed parallel to the cylinder axis in the liquid. These conductors are connected to the alternating current. First published online: 14 Oct 2010
Grand-canonical approach to density functional theory of electrocatalytic systems: Thermodynamics of solid-liquid interfaces at constant ion and elec…
2018
Properties of solid-liquid interfaces are of immense importance for electrocatalytic and electrochemical systems, but modeling such interfaces at the atomic level presents a serious challenge and approaches beyond standard methodologies are needed. An atomistic computational scheme needs to treat at least part of the system quantum mechanically to describe adsorption and reactions, while the entire system is in thermal equilibrium. The experimentally relevant macroscopic control variables are temperature, electrode potential, and the choice of the solvent and ions, and these need to be explicitly included in the computational model as well; this calls for a thermodynamic ensemble with fixed…
A tight-binding potential for the simulation of solid and liquid iodine
2003
In this work, we suggest an interatomic potential for iodine applicable to the simulation of the condensed phases of the halogen within the temperature and density range accessible to experiments. The potential includes an attractive term that is partitioned into directional chemical bonding with a many-particle character and a pairwise interaction. Despite its simplicity, the potential reproduces the crystal structure of solid iodine, the presence of atomic phases with increasing pressure, and the metallic or insulating character of the solid phases. Finally, we present preliminary simulation results for fluid iodine.
Observable Streaming Potential in Membranes
2003
Theories describing the electrokinetic processes in membranes usually involve nonobservable variables. One of these phenomena is the streaming potential, i.e., the electric potential generated by a pressure difference imposed across the membrane system. In this work the streaming potential is successfully described by using observable variables in the framework of thermodynamics of irreversible processes. The observable electric potential is the central quantity of the transport equations. The relaxation with time of this electric potential difference is well explained by the solute flux in these transport equations. The fluxes and forces defined in the formulation permit one to analyze the…
Layer-Wise Discontinuous Galerkin Methods for Piezoelectric Laminates
2020
In this work, a novel high-order formulation for multilayered piezoelectric plates based on the combination of variable-order interior penalty discontinuous Galerkin methods and general layer-wise plate theories is presented, implemented and tested. The key feature of the formulation is the possibility to tune the order of the basis functions in both the in-plane approximation and the through-the-thickness expansion of the primary variables, namely displacements and electric potential. The results obtained from the application to the considered test cases show accuracy and robustness, thus confirming the developed technique as a supplementary computational tool for the analysis and design o…
Oб определении внутримолекулярной потенциальной функции многоатомной молекулы H2S
2008
In modern molecular physics, there are two basic methods of determining the intramolecular potential function of polyatomic molecules. The first method is ab initio calculations and the second is the so-called semi-empirical method in which the Hamiltonian parameters are varied by direct construction of the Hamiltonian matrix. In the present work, the second approach is discussed on the example of the XY2 three-atomic molecule of the C2v symmetry. On the one hand, it is extremely simple for implementation, and on the other hand, it considerably extends the capability of application of the traditional semi-empirical methods. The approach suggested involves two aspects that make it advantageo…
Preparation of ferulic acid derivatives and evaluation of their xanthine oxidase inhibition activity.
2007
Several ferulic acid ethyl esters (3a-h) were synthesized under the Knoevengel reaction condition and they were further reduced to afford the respective allylic alcohol derivatives (4a-g). Some of them were evaluated for the xanthine oxidase (XO) inhibitory activity. Among them, 3h exhibited a significant inhibitory activity with an IC50 value of 1.35 x 10(-5) M, while the IC50 value of allopurinol used as the positive control was 1.49 x 10(-5) M. The study suggested that the higher acidity of the phenolic OH group in the ferulic acid derivatives might result in improved XO inhibitory activity.