702 research outputs found
Evaluation of the chemical additive effect on asphaltene aggregation in dead oils: a comparative study between ultraviolet–visible and near-infrared-laser light scattering techniques
Asphaltenes flocculate as a consequence of changes in the temperature, pressure, or composition. This flocculation can result in several oil production problems. The application of chemical additives (inhibitors or dispersants) is a well-known way to control asphaltene flocculation. Ultraviolet-visible (UV-vis) spectroscopy is the most common analytical technique that has been applied to study the effectiveness of chemical additives in keeping asphaltene particles dispersed into crude oils. However, this technique requires being performed in diluted solutions, which can interfere significantly in the aggregation phenomena. The objective of this work was to evaluate the effect of three chemical additives, 4-dodecyl benzenesulfonic acid (DBSA) and two commercial products (CO and C1), on the asphaltene aggregation behavior of two Brazilian crude oils, using near-infrared (NIR)-laser (lambda = 1550 nm) scattering measurements. This is a new methodology developed to study the aggregation kinetics and settling of asphaltenes around its n-heptane flocculation onset. The NIR-laser scattering method offers the possibility to work with samples at a higher crude oil concentration, being more representative of real systems. The results obtained were compared to those determined with the traditional UV-vis method (lambda = 850 nm) and showed qualitatively similar trends. Settling measurements suggest that the stabilization provided by the additives can occur by slowing both formation and growing of asphaltene particles and delaying the phase separation process. DBSA was more effective in keeping the asphaltene particles dispersed in solution and prevented them from settling at lower concentrations when compared to commercial products, for both crude oils studied. It was demonstrated that the methodology developed using NIR-laser scattering was more accurate and sensitive.Asphaltenes flocculate as a consequence of changes in the temperature, pressure, or composition. This flocculation can result in several oil production problems. The application of chemical additives (inhibitors or dispersants) is a well-known way to cont29528132822sem informaçãosem informaçãoThe authors acknowledge Petrobras for their financial suppor
Mobile phone and tablet apps to support young people’s management of their physical long-term conditions: a systematic review protocol
Background: The prevalence of long-term or chronic conditions that limit activity and reduce quality of life in young people aged 10-24 years is rising. This group has distinct health care needs and requires tailored support strategies to facilitate increasing personal responsibility for the management of their condition wherever possible, as they mature. Mobile phone and tablet mobile technologies featuring software program apps are already well used by young people for social networking or gaming. They have also been utilized in health care to support personal condition management, using condition-specific and patient-tailored software. Such apps have much potential, and there is an emerging body of literature on their use in a health context making this review timely. Objective: The objective of this paper is to develop a systematic review protocol focused on identifying and assessing the effectiveness of mobile phone and tablet apps that support young people’s management of their chronic conditions. Methods: The search strategy will include a combination of standardized indexed search terms and free-text terms related to the key concepts of young people; long-term conditions and mobile technology. Peer-reviewed journal articles published from 2003 that meet the inclusion and exclusion criteria will be identified through searching the generated hits from 5 bibliographical databases. Two independent reviewers will screen the titles and abstracts to determine which articles focus on testing interventions identified as a mobile phone or tablet apps, and that have been designed and delivered to support the management of long-term conditions in young people aged 10-24 years. Data extraction and quality assessment tools will be used to facilitate consistent analysis and synthesis. It is anticipated that several studies will meet the selection criteria but that these are likely to be heterogeneous in terms of study design, reported outcomes, follow-up times, participants’ age, and health condition. Sub-group analyses will be undertaken and where possible meta-analyses will take place.Results: This review will synthesize available knowledge surrounding tablet and mobile phone apps that support management of long term physical health conditions in young people. The findings will be synthesized to determine which elements of the technologies were most effective for this population. Conclusions: This systematic review aims to synthesize existing literature in order to generate findings that will facilitate the development of an app intervention. The review will form the first phase of development and evaluation of a complex intervention as recommended by the United Kingdom Medical Research Council. The knowledge gained from the review will be verified in subsequent phases, which will include primary qualitative work with health professionals and young people with long term conditions as research participants. Young people living with long-term conditions will be involved as co-researchers and consumer advisors in all subsequent phases to develop and evaluate an app to support the management of long-term physical health conditions
Cooperative maneuvers applied to automated vehicles in real and virtual environments
[ES] En los últimos años los Sistemas Inteligentes de Transporte, ITS (del inglés, Intelligent Transportation System) se han convertido en una realidad dentro de la sociedad, aportando soluciones y beneficios a la conducción. Con el fin de contribuir a su desarrollo, el presente trabajo describe un marco cooperativo híbrido capaz de validar maniobras entre múltiples vehículos (virtuales y reales), con el fin de disminuir los costos, tiempos y riesgos asociados al ajuste de los controladores. Para su validación se presentan 3 casos de estudios. El primero consiste en utilizar dos vehículos virtuales para realizar un Control de Crucero Adaptativo, ACC (del inglés, Adaptive Cruise Control) con seguidor de trayectoria. El segundo, emplea un coche real como seguidor y un coche virtual como líder para la maniobra de Stop & Go. Finalmente, se utilizan dos vehículos reales para el ACC. Los algoritmos de seguimiento empleados para las maniobras cooperativas están basados en controladores de lógi[EN] In recent years, Intelligent Transportation Systems (ITS) have become a reality within society, by providing benefits and solutions to the conduction. With the aim of contributing with the development of the ITS, the present work describes a hybrid cooperative framework for the validation of maneuvers between multiple vehicles (virtual and real), in order to reduce cost, time and risks associated with the controllers adjustment. For its validation three case of studies are presented. The first one consists of using two virtual vehicles to perform an Adaptive Cruise Control (ACC) with trajectory tracker. The second one, in using a real car as the follower and a virtual vehicle as the lider to perform a Stop & Go. And finally, two real cars are used to carry out an ACC. The tracker algorithms employed for the cooperative maneuvers are based in fuzzy logic controllers. The results show the versatility of the proposed framework, which was able to correctly execute the maneuvers in eachProyecto SerIoT H2020 (Con número de concesiòn 780139)Hidalgo, C.; Marcano, M.; Fernández, G.; Pérez, JM. (2020). Maniobras cooperativas aplicadas a vehículos automatizados en entornos virtuales y reales. Revista Iberoamericana de Automática e Informática industrial. 17(1):56-65. https://doi.org/10.4995/riai.2019.111555665171Cuadrado, J., Vilela, D., Iglesias, I., Martín, A., Peña, A., 2013. A multibody model to assess the effect of automotive motor in-wheel configuration on vehicle stability and comfort. ECCOMAS Multibody Dynamics.Da Cunha, F. D., Boukerche, A., Villas, L., Viana, A. C., Loureiro, A. A., 2014. Data communication in vanets: a survey, challenges and applications. Ph.D. thesis, INRIA Saclay; INRIA. https://doi.org/10.1016/j.adhoc.2016.02.017Driankov, D., Hellendoorn, H., Reinfrank, M., 1996. Introduction. In: An Introduction to Fuzzy Control. Springer, pp. 1-36. https://doi.org/10.1007/978-3-662-03284-8During, M., Lemmer, K., 2016. Cooperative maneuver planning for cooperative driving. IEEE Intelligent Transportation Systems Magazine 8 (3), 8-22. https://doi.org/10.1109/MITS.2016.2549997Española, D. G. D. T., Jul. 2015. Seguridad vial. http://www.dgt.es/es/seguridad-vial/.Fernandez, S., Ito, T., nov 2016. Driver classification for intelligent transportation systems using fuzzy logic. In: 2016 IEEE 19th International Conference on Intelligent Transportation Systems (ITSC). IEEE. https://doi.org/10.1109/ITSC.2016.7795711Festag, A., 2014. Cooperative intelligent transport systems standards in europe. IEEE communications magazine 52 (12), 166-172. https://doi.org/10.1109/MCOM.2014.6979970González, D., Pérez, J., Milanés, V., Nashashibi, F., 2016. A review of motion planning techniques for automated vehicles. IEEE Transactions on Intelligent Transportation Systems 17 (4), 1135-1145. https://doi.org/10.1109/TITS.2015.2498841Iancu, I., 2012. A mamdani type fuzzy logic controller. In: Fuzzy Logic-Controls, Concepts, Theories and Applications. InTech. https://doi.org/10.5772/36321Jena, K. S., Joseph, A. V., Senapati, P. R. R., 2016. Fuzzy logic based approach for controlling of a vehicle in its longitudinal motion. Middle-East Journal of Scientific Research 24 (S1), 346-352. https://doi.org/10.1017/S1047198700014406Lattarulo, R., González, L., Martí, E., Matute, J., Marcano, M., Pérez, J., 2018. Urban motion planning framework based on n-bézier curves considering comfort and safety. Journal of Advanced Transportation 2018. https://doi.org/10.1155/2018/6060924Lattarulo, R., Marcano, M., Pérez, J., 2017a. Overtaking maneuver for automated driving using virtual environments. In: International Conference on Computer Aided Systems Theory. Springer, pp. 446-453. https://doi.org/10.1007/978-3-319-74727-9Lattarulo, R., Pérez, J., Dendaluce, M., 2017b. A complete framework for developing and testing automated driving controllers. IFAC-PapersOnLine 50 (1), 258-263. https://doi.org/10.1016/j.ifacol.2017.08.043Lin, W.-Y., Li, M.-W., Lan, K.-C., Hsu, C.-H., 2010. A comparison of 802.11 a and 802.11 p for v-to-i communication: A measurement study. In: International Conference on Heterogeneous Networking for Quality, Reliability, Security and Robustness. Springer, pp. 559-570. https://doi.org/10.1007/978-3-642-29222-4Marcano, M., Matute, J. A., Lattarulo, R., Martí, E., Pérez, J., 2018. Low speed longitudinal control algorithms for automated vehicles in simulation and real platforms. Complexity 2018. https://doi.org/10.1155/2018/7615123Marzbanrad, J., Moghaddam, T.-z., et al., 2015. Prediction of drivers accelerating behavior in the stop and go maneuvers using genetic algorithm-artificial neural network hybrid intelligence. International Journal of Automotive Engineering 5 (2), 986-998.Milanés, V., Villagrá, J., Godoy, J., González, C., 2012. Comparing fuzzy and intelligent pi controllers in stop-and-go manoeuvres. IEEE Transactions on Control Systems Technology 20 (3), 770-778. https://doi.org/10.1109/TCST.2011.2135859Milanes, V., Villagra, J., Godoy, J., Simo, J., Pérez, J., Onieva, E., 2012. An intelligent v2i-based traffic management system. IEEE Transactions on Intelligent Transportation Systems 13 (1), 49-58. https://doi.org/10.1109/TITS.2011.2178839Morcillo, C. G., 2011. Lógica difusa. una introducción práctica. Universidad de Castilla-La Mancha.Pérez, J., Milanés, V., Alonso, J., Onieva, E., De Pedro, T., 2010. Adelantamiento con vehículos autónomos en carreteras de doble sentido. Revista Iberoamericana de Automática e Informática Industrial RIAI 7 (3), 25-33. https://doi.org/10.1016/S1697-7912(10)70039-XRastelli, J. P., Peñas, M. S., 2015. Fuzzy logic steering control of autonomous vehicles inside roundabouts. Applied Soft Computing 35, 662-669. https://doi.org/10.1016/j.asoc.2015.06.030Rizvi, R., Kalra, S., Gosalia, C., Rahnamayan, S., 2014. Fuzzy adaptive cruise control system with speed sign detection capability. In: Fuzzy Systems (FUZZ-IEEE), 2014 IEEE International Conference on. IEEE, pp. 968-976. https://doi.org/10.1109/FUZZ-IEEE.2014.6891748Schmied, R., Moser, D.,Waschl, H., del Re, L., 2016. Scenario model predictive control for robust adaptive cruise control in multi-vehicle traffic situations. In: Intelligent Vehicles Symposium (IV), 2016 IEEE. IEEE, pp. 802-807. https://doi.org/10.1109/IVS.2016.7535479Sriranjan, S., Lattarulo, R., Pérez-Rastelli, J., Ibanez-Guzman, J., Pena, A., 2017. Lateral controllers using neuro-fuzzy systems for automated vehicles: A comparative study.Sugeno, M., 1985. An introductory survey of fuzzy control. Information sciences 36 (1-2), 59-83. https://doi.org/10.1016/0020-0255(85)90026-XSugeno, M., Murakami, K., 1984. Fuzzy parking control of model car. In: Decision and Control, 1984. The 23rd IEEE Conference on. Vol. 23. IEEE, pp. 902-903. https://doi.org/10.1109/CDC.1984.272144Villagrá, J., Milanés, V., Pérez, J., González, C., 2010. Model-free control techniques for stop & go systems. In: Intelligent Transportation Systems (ITSC), 2010 13th International IEEE Conference on. IEEE, pp. 1899-1904. https://doi.org/10.1109/ITSC.2010.5625228Wang, X., Fu, M., Ma, H., Yang, Y., 2015. Lateral control of autonomous vehicles based on fuzzy logic. Control Engineering Practice 34, 1-17. https://doi.org/10.1016/j.conengprac.2014.09.015Zohdy, I. H., Kamalanathsharma, R. K., Rakha, H., 2012. Intersection management for autonomous vehicles using icacc. In: Intelligent Transportation Systems (ITSC), 2012 15th International IEEE Conference on. IEEE, pp. 1109-1114. https://doi.org/10.1109/ITSC.2012.633882
Maniobras cooperativas aplicadas a vehículos automatizados en entornos virtuales y reales
In recent years, Intelligent Transportation Systems (ITS) have become a reality within society, by providing benefits and solutions to the conduction. With the aim of contributing with the development of the ITS, the present work describes a hybrid cooperative framework for the validation of maneuvers between multiple vehicles (virtual and real), in order to reduce cost, time and risks associated with the controllers adjustment. For its validation three case of studies are presented. The first one consists of using two virtual vehicles to perform an Adaptive Cruise Control (ACC) with trajectory tracker. The second one, in using a real car as the follower and a virtual vehicle as the lider to perform a Stop & Go. And finally, two real cars are used to carry out an ACC. The tracker algorithms employed for the cooperative maneuvers are based in fuzzy logic controllers. The results show the versatility of the proposed framework, which was able to correctly execute the maneuvers in each of the test environments.Los autores quieren agradecer al proyecto SerIoT H2020 (Con numero de concesión 780139) por su apoyo en el desarrollo de este trabajo
A candidate magnetic helium core white dwarf in the globular cluster NGC 6397
We report a peculiar variable blue star in the globular cluster NGC 6397,
using Hubble Space Telescope optical imaging. Its position in the
colour-magnitude diagrams, and its spectrum, are consistent with this star
being a helium core white dwarf (He WD) in a binary system. The optical light
curve shows a periodicity at 18.5 hours. We argue that this periodicity is due
to the rotation of the WD and possibly due to magnetic spots on the surface of
the WD. This would make this object the first candidate magnetic He WD in any
globular cluster (GC), and the first candidate magnetic WD in a detached binary
system in any GC and one of the few He WDs with a known rotation period and of
magnetic nature. Another possibility is that this system is a He WD in a binary
system with another WD or another degenerate object, which would make this
object one of the few candidate non-accreting double degenerate binaries in any
GC.Comment: Accepted for publication in MNRA
Neorealism and the Organization of American States (OAS): an examination of CARICOM rationality toward Venezuela and the United States
Since 2017, CARICOM member states have been divided in the positions they take on Organization of American States (OAS)
resolutions addressing political instability in Venezuela. This article uses a neorealism framework to determine whether or
not the provision of energy investments by Venezuela and the United States to CARICOM member countries is an attempt
on their part to skew the OAS voting mechanism in their national interests. The article also examines the extent to which
CARICOM member states’ response to Venezuela’s and United States’ interest in the OAS demonstrates a pattern of
rationality. The findings suggest that though the OAS provides a medium for states to negotiate mutually beneficial solutions,
states are rational actors and even where they do corporate, dominant states may try to manifest their self-interest
Gestión de la innovatividad universitaria
oai:ojs2.ambientevirtualuea.org:article/3Universities are called to offer answers to the complexities of the contemporary world, with significant contributions to the development of countries in terms of overcoming inequalities, poverty and exclusion; together with the rational use of resources that guarantees human survival in sustainability with the environment. Innovation is one of the central characteristics in the training profiles, with a view to increasing the capacity of universities to generate solutions to local problems, and a feature that enhances the employability of graduates. Within the framework of experiences for the formation of innovative skills in university students, the study presents the results of an investigation under the paradigm of reflexivity, with the aim of representing in a management model the actions carried out by a commission in charge of the promotion of innovation in a university in Venezuela, during 1998 - 2015. From the recovery of documentary sources, interviews and participant observations, the members analyzed, collated and synthesized the historical memory of the commission, elaborating the Management Model of the University innovation. The axes, processes and values that enable the virtuous confluence of articulated capacities and attitudes, of organizations, people and systems, to generate innovations are described. The model provides good practices of high applicability and transfer for the promotion of a culture of innovation in universities.Las universidades están llamadas a ofrecer respuestas a las complejidades del mundo contemporáneo, con aportes significativos para el desarrollo de los países en términos de superación de las desigualdades, pobreza y exclusión; junto con el aprovechamiento racional de los recursos, que garanticen la supervivencia humana en sustentabilidad con el ambiente. La innovación es una de las características centrales en los perfiles de formación, con miras a incrementar la capacidad de las universidades para generar soluciones a problemas locales; es además un rasgo que potencia la empleabilidad de los egresados. En el marco de experiencias para la formación de competencias innovadoras en estudiantes universitarios, este estudio presenta los resultados de una investigación bajo el paradigma de la reflexividad, con el objetivo de representar en un modelo de gestión, las acciones adelantadas por una comisión a cargo de la promoción de la innovación en una universidad de Venezuela, durante 1998 – 2015. A partir de la recuperación de fuentes documentales, entrevistas y observaciones participantes, los miembros analizaron, cotejaron y sintetizaron la memoria histórica de la comisión, elaborando el Modelo de Gestión de la Innovatividad Universitaria. Se describen los ejes, procesos y valores que posibilitan la confluencia virtuosa de capacidades y actitudes articuladas, de organizaciones, personas y sistemas, para generar innovaciones. El modelo aporta buenas prácticas de alta aplicabilidad y transferencia para la promoción de una cultura de la innovación en las universidades
Substitutional effects of in by Cu in CeIn2
We have investigated the evolution of the magnetic properties on the Ce(In1'xCux)2 (0 < x ≤ 0.3) series of alloys. The orthorhombic structure of the CeIn2 alloy (Imma) changes into the hexagonal AlB2-type (P6/mmm) for x = 0.05 and, then, into the hexagonal CaIn2-type (P63/mmm) for higher Cu concentrations, up to x = 0.3. The dc (ac) magnetic susceptibility shows an abrupt decrease of the magnetic transition temperature from 22 K to 5.4 K (x = 0.05). The results indicate the influence of the crystallographic type of structure and disorder effects on the magnetic behavior along the series. © Owned by the authors, published by EDP Sciences, 2014
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