959 research outputs found
The Charm of the Proton and the Production
We propose a two component model for charmed baryon production in
collisions consisting of the conventional parton fusion mechanism and
fragmentation plus quarks recombination in which a valence diquark from
the proton recombines with a -sea quark to produce a . Our
two-component model is compared with the intrinsic charm two-component model
and experimental data.Comment: 6 pages, LaTex, 2 figures included, aipproc.sty included. Talk
presented at Simposio Latino Americano de Fisica de Altas Energias, Merida,
Mexico, November 199
The Polarization and the Recombination Mechanism
We use the recombination and the Thomas Precession Model to obtain a
prediction for the polarization in the
reaction. We study the effect of the recombination function on the
polarization.Comment: 4 pages, LaTex, 1 figures included, aipproc.sty included. Talk
presented at Simposio Latino Americano de Fisica de Altas Energias, Merida,
Mexico, November 199
Alteration and alterability of the anorthosite from Angola
Siliceous rocks are widely used as dimension stone but the last decades have registered an increase rate of their alteration when exposed to polluted environments. Anorthosites were treated by acidified solutions of HCl, HN03 and H2S04 simulating acid rain and the response was recorded through different experiments such as on the surface of the polished rock and on the surface of uncovered thin sections. The main components, plagioclase and olivine, both responded in similar ways to each acid solution, although following different trends; while plagioclase develops a thin layer which acts as protection to the mineral, olivine at first undergoes alteration due to leaching of magnesium and iron and in a following stage, is mechanically removed from the rock. The
action of warm water on the rock was tested through the use of the Soxhlet extractor which caused changes on the rock colour
and leaching of several cations from its components
Solubility studies of trans-cinnamic acid in mixed solvents
Phenolic acids are a subclass of phenolic compounds with chemical and biological properties of interest in the pharmaceutical and food industries. The design of their extraction and separation processes includes the knowledge of their thermophysical properties as well as multicomponent solid-liquid equilibria data.
For these compounds, even essential solubility data in pure organic solvents and water are scarce. Therefore, in this work, trans-cinnamic acid was chosen as a model compound for which only a few solubility data in pure water and alcohols can be found in the literature [1-3].
The solubility of trans-cinnamic acid in the mixed solvents water + ethanol, and water + methanol was measured, at 298.15 K, using the isothermal shake-flask method and quantitative analysis either by gravimetry or UV spectrophotometry. As can be seen in Fig. 1, the solubility of the acid can significantly
increase with the addition of the alcohol, with a more pronounced effect induced by ethanol. In a complementary approach and aiming to search for other methods to increase the aqueous solubility of
trans-cinnamic acid, the phase-solubility diagram was determined for systems containing α-cyclodextrin.
References
[1] J. Li, Z. Zeng, L. Sun, W. Xue, H. Wang, Journal of Chemical and Engineering Data, 61 (2016) 1192â1198.
[2] F. Mota, A. Queimada,, S. Pinho, E. Macedo, Industrial and Engineering Chemistry Research, 47 (2008) 5182-5189.
[3] Solubilities of Organic Compounds in Organic Solvents, J. Bradley, C. Neylon, R. Guha, A. Williams, B. Hooker, A. Lang, B. Friesen, Open Notebook Science, 2009.This work was financially supported by: Project POCI-01-0145-FEDER-006984 â Associated Laboratory LSRELCM
funded by FEDER funds through COMPETE2020 - Programa Operacional Competitividade e
Internacionalização (POCI) â and by national funds through FCT - Fundação para a CiĂȘncia e a Tecnologia.info:eu-repo/semantics/publishedVersio
Factor de qualidade em rochas ornamentais com base em ensaios mecĂąnicos e envelhecimento artificial
Distinguishing sequences for partially specified FSMs
Distinguishing Sequences (DSs) are used inmany Finite State Machine (FSM) based test techniques. Although Partially Specified FSMs (PSFSMs) generalise FSMs, the computational complexity of constructing Adaptive and Preset DSs (ADSs/PDSs) for PSFSMs has not been addressed. This paper shows that it is possible to check the existence of an ADS in polynomial time but the corresponding problem for PDSs is PSPACE-complete. We also report on the results of experiments with benchmarks and over 8 * 106 PSFSMs. © 2014 Springer International Publishing
Creating a benchmark of vertical axis wind turbines in dynamic stall for validating numerical models
Bio4gas : evaluation and analysis of wastewater treatment facilities in the scope of biogas production maximization and energy production optimization
The present work presents some of the results of five reports developed in the scope of optimization feasibility studies carried out at 6 small- and medium-sized wastewater treatment plants (WWTP) in Portugal. These 6 WWTP are operated by five companies that belong to the Ăguas de Portugal holding. The objective of the studies was twofold: to
assess to which extent the production of biogas could be increased by means of
operational modifications and/or by the implementation of co-digestion regimes; and also
to simulate different scenarios for feed-in tariff of electricity taking in account energy
prices calculated based upon the DL n.Âș 225/2007 of 11th May. In this way, several codigestion
scenarios were defined based upon standard available organic residues. The
results obtained showed that the implementation of co-digestion regimes represent a
significative potential to increase the production of biogas, in some cases, over 600%.
Even though, it was concluded that in some cases the costs of introducing new regimes
of energy management were not supported by the increase of energy production, so a
scale factor is associated to the revenues. This study contributed to the establishment of
specific needs in terms of information management (digester operation, energy
production/consumption, strategy for optimisation)
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