bluuebunny/crossref_metadata_2025 huggingface dataset:
Increasing the Efficiency of Asphalt by Introducing Additives Containing Polyphosphoric Acid
Authors: Yadykina Valentina V. , Pashkova Christina
Published: January 2016

Bitumen modified by polyphosphoric acid (PPA), as well as in combination with polymers and is widely used for production of road bitumen, which correspond to high standards. Therefore, the aim of this work is to study the influence of the properties of the polyphosphoric acid with different contents of phosphorous oxide (P2O5) and a derivative of them based additives esters of polyphosphoric acid and synthetic phospholipids DAD-KT, developed by "Selena".The influence of these additives on the change of adhesive, cohesive properties of bitumen, as well as on the properties of asphalt concrete to change of the limits of the crushing stress, water saturation and long waterproof. The use of additives had a positive effect on the adhesion of bitumen with mineral material. The index of cohesion increased with the addition of DAD-KT, more than 80%. This is due to the presence in its structure of the polymer.In connection with the increase of adhesion and cohesion of asphalts modified polyphosphoric acid, asphalt concrete prepared with these binders should be characterized by the increased values of water, heat and frost resistance and resistance to rutting.Study of the influence of additives on the physico-mechanical characteristics of asphalt concrete shows a positive effect on the properties of the latter. So the strength of asphalt concrete at 20 °C has risen on average by 10 % relative to the initial bitumen without additives, the strength at 50 °C by 15 %, the strength at 0 °C decreased by 8-12 %, the water saturation decreased by 30-40 %, indicating that the decrease in porosity of asphalt concrete and increase the durability of asphalt to seasonal temperature changes. In turn, the resistance increased by 5-8 % relative to the bitumen without additives. Long resistant with additives also increased which can be explained by the improvement of adhesion of bitumen with mineral materials of asphalt concrete. So the resistance after 15 days of the original bitumen and bitumen with additives decreased by 15 and an average 5 %, respectively, after 30 days at 25 and 7 % respectively. It can be concluded that in the modification of bitumen polyphosphoric acid, and in particular the addition of DAD-KT, there has been a significant improvement in the properties of bitumen and asphalt concrete. Therefore, it is possible to expect the improvement of the quality of the road pavement made of asphalt, with the use of additives containing polyphosphoric acid, in particular - DAD-KT.
Properties of Cement Paste with Incorporated Sodium Silicate
Authors: Pokorný Jaroslav , Záleská Martina , Pavlíková Milena , Rovnaníková Pavla , Pavlík Zbyšek
Published: January 2016

Sodium silicate, usually known as water glass, is researched as material that can potentially find use in composition of cement based matrix in order to improve its porous structure and related physical parameters. The water glass is applied in cement paste mixture in an amount of 5, 10, 15, and 20 mass% of cement. The water dosage is experimentally accessed in order to attain the same workability of particular mixtures. For the applied water glass and cement, the particle size distribution is measured on laser diffraction principle. Pozzolanic activity of water glass is investigated using modified Chapelle test. The particular studied cement pastes are cured 28 days in water and characterized by basic physical and mechanical properties, whereas the results of mechanical resistivity are supported by pore size distribution data accessed by mercury intrusion porosimetry. Althought the particles of applied water glass are coarser than that of cement and did not exhibit pozzolanic activity, their application partially tightened the porous structure of hydrated products and thus contributed to the mechanical strength by means of filler effect. This makes good prerequisites for future research that will be focused on a development of new types of cement-based composites with incorporated sodium silicate used as an modifying admixture.
Basic Physical and Mechanical Properties of Composites Based on Three Different Cements
Authors: Čáchová Monika , Vejmelková Eva , Šestáková Kateřina , Reiterman Pavel , Keppert Martin , Koňáková Dana , Černý Robert
Published: January 2016

This article is focused on cement based composites. Two cements differing in mineralogical composition are utilised as main binder in composites mixtures. Results of measured physical parameters of studied materials are presented. For the sake of comparison, a reference material with Portland cement was also prepared. Basic physical properties (measured by water vacuum saturation method and by helium pycnometry), characterizations of pore system (determined by mercury porosimetry) and mechanical properties are the matter of this study. Composites show various open porosity; the results of open porosity of materials containing special cements show higher values, in comparison with composite based on Portland cement. This fact of course influences other material characteristics - mainly mechanical properties.
The Effect of Surface Treatments of Textile Reinforcement on Mechanical Parameters of HPC Facade Elements
Authors: Vlach Tomáš , Laiblová Lenka , Ženíšek Michal , Chira Alexandru , Kumar Anuj , Hájek Petr
Published: January 2016

Development of extremely thin concrete structures and demand for extremely thin elements are the reason of using composite non-traditional materials as reinforcement. Steel reinforcement is not very chemically resistant and it limits the thickness because of the required concrete cover as protection. This is the reason why textile reinforced concrete (TRC) going to be very famous and modern material. TRC in combination with fine grain high performance concrete (HPC) allows a significant saving of concrete. Due to its non-corrosive properties of composite technical textiles it is possible to design very subtle structures and elements. TRC and HPC in general are developed at the Faculty of Civil Engineering and the Klokner Institute, CTU in Prague. This present paper investigates the cohesion influence of textile reinforcement on four point bending test. All small experimental panels were reinforced with the same 3D technical textile from AR-glass roving with different type of cover layer. Different conditions of interaction between technical textiles and HPC were ensured by modified surface using silica sand and silica flour.
Influence of Moisture Content on the Thermal Properties of Concrete Containing Agricultural Waste Materials
Authors: Koňáková Dana , Čáchová Monika , Vejmelková Eva
Published: January 2016

This article deals with concrete containing waste material originating in a coir fibres extraction from outer protective peel of a coconut. Coir pith is used as cement replacement in amount of 5% and 10%. The influence of moisture content on the thermal properties of studied concrete is determined by means of experimental measurements of basic physical properties, hygric transport parameters and thermal characteristics. From achieved results it can be concluded, that the higher amount of coir pith is used, the better values of thermal characteristics material show. But at the same time thermal characteristics are more influenced by moisture content.
Tests of Selected Properties of Aggregates on Ceramic Wastes
Authors: Koper Artur
Published: January 2016

The article analysed the results of comparative sampling of selected properties of concretes with addition of aggregates from sanitary ceramic wastes. For the need of the analyses there were created concretes of various w/c coefficients (0,35, 0,50, 0,75) and with diverse percentage participation of ceramic wastes aggregates (exchange of 50% and 100% coarse aggregates into ceramic). The range of performed samples and analyses included sampling of mechanical and physical properties of concretes and the aggregates used. What was under analysis: for aggregates – sampling of bulk density, absorbency, resistance to crushing; for concretes from ceramic wastes – sampling of density, absorbency, compressive strength, tensile strength and compressive strength after roasting. Roasting was performed according to defined temperature cycles: cycle I - from 0 to 150OC (vaporisation of free water), cycle II - from 150 to 550OC (separation of chemically combined water), cycle III - beyond 550OC (change of hydraulic combination into ceramic, sintering).
Energy Saving Additives «RAA WAC» for Production of Warm Asphalt Concrete
Authors: Yadykina Valentina V. , Gridchin Anatoly M. , Trautvain Anna , Kholopov Vladimir
Published: January 2016

For the last 15-20 years in Europe and in the USA the new technologies allowing to reduce temperature of hashing and consolidation of the asphalt concrete mix prepared on viscous bitumen by 20-40 °C were developed. Thus characteristics of a covering in comparison with use of traditional hot asphalt concrete don't worsen.One of ways of achievement of effect is application of special chemical additives.Results of researches of influence of the additives developed by authors together with the enterprise of "Selena" for production of warm asphalt concrete of the series «RAA WAC» on properties of bitumen and asphalt concrete in comparison with a known additive of Evotherm J1 are given in the real work.It is established that the studied additives at increase of their concentration in knitting a little reduce conditional viscosity of bitumen, raise tensile properties at a temperature of 25 °C, practically don't influence softening temperature.
An Experimental Study on the Self-Consolidating Concrete (SCC) under Hot Weather and Hauling Time
Authors: Al Martini Samer , Al Khatib Mohamed
Published: January 2016

Self-consolidating-concrete (SCC) has gained wide acceptance in the construction industry given its ability to reduce construction duration and cost. All ready-mix concrete commonly used in hot weather countries, such as United Arab Emirates (UAE), is subjected to continuous agitation during hauling to construction sites. Prolonged mixing, especially at high temperatures can lead to loss of workability and increased difficulties for concrete placement and consolidation. This may result in lower mechanical and durability properties. In this paper, the mechanical and durability properties of self-consolidating concrete (SCC) under hot weather conditions were investigated. Mixing and testing were conducted outdoor at the construction material lab of Abu Dhabi University during last summer of 2014. The test results showed that the mixing time and hot weather adversely affected the fresh properties. The SCC mixtures were continuously mixed for 2 hours under a temperature ranged from 25 to 40 °C, to simulate concrete in a transit truck during transportation to a construction site under hot weather. Polycarboxylate-based high-range water-reducing admixture (PC) and fly ash were incorporated in the investigated SCC mixtures. The results showed that both the compressive strength and durability of SCC were highly affected by fly ash dosage and temperature.Keywords: Hot weather; hauling time, self-consolidating concrete.
Experimental Verification of Behavior of Glass and Carbon Fibers in Alkali Environment
Authors: Girgle Frantisek , Bodnárová Lenka , Kučerová Anna , Janák Petr , Prokeš Jan
Published: January 2016

The paper discusses durability of glass and carbon fibers which are exposed to alkali environment of concrete. Mainly glass fibers are affected by the high alkali environment with pH of concrete exceeding 12.0. The degradation of fibers is reflected by decreasing of its tension strength, while the rate of decreasing is depended on exposition time and temperature. The paper briefly presents results of a large experimental investigation which should specify an influence of alkali ions concentration in a solution on reduction of the mechanical properties of fibers. Reference samples were immersed in a bath with distilled water and the others were stored at ambient air only.
Characteristic Properties of the Fly Ash from Coal Combustion
Authors: Polacek Jaromir , Šulc Rostislav , Formáček Petr
Published: January 2016

Environmental impacts and sustainable development are two words, which are mentioned every day. The responsibility of our generation is growing up. People consider about the new ways of using materials. Some of them were waste in the recent past. In present time people think about the possibilities how the waste could be reduced, recycled, reused or recovered. In this paper are presented the chemical and physical properties of different coal ash. In the research were tested the XRD analyse, the quantity of Free CaO, the granulometry, volume stability, loose bulk density and shake down loose bulk density.
Rheological Characteristics of Alkali Activated Fly-Ash Concrete Mixtures
Authors: Váchal Tomáš , Šulc Rostislav , Svoboda Pavel
Published: January 2016

This paper describes rheological characteristics of concrete mixtures based on alkali-activated fly ash. There are shown relationships between workability of fly-ash fresh concrete mixtures and water–fly-ash ratio in fresh alkali-activated concrete. In addition, there is described relationship between workability in fresh mixture on compressive strength of alkali-activated concrete.
Dosage of Silica Fume in High Performance Concrete
Authors: Ženíšek Michal , Vlach Tomáš , Laiblová Lenka
Published: January 2016

Durability and high strength of concrete are closely associated with low porosity and generally denser material structure. This is achieved using the addition, which include also silica fume. This article deal with an effective dosage of silica fume in high performance concrete, in a proportion of 0-25 % by the weight of cement. Compressive strength, rheological behaviour and economic benefits were the main questions in this work. The expected increase in compressive strength showed itself in lower doses of silica fume, while higher doses did not produce a further increase in strength. In the case of rheological behaviour, we can confirm lower bleeding and segregation, but also faster drying of the surface layer. From the economic point of view, a small doses of silica fume are better, because then we have observed the highest increase in strength.
Lower Viséan ammonoids from the lower Mount Head Formation, east-central British Columbia
Authors: Work D M , Nassichuk W W , Richards B C
Published: January 2016

Lower Viséan (upper middle Osagean) ammonoids from microbial carbonate mud mounds in the lower member of the Mount Head Formation in the Monkman Pass map area of east-central British Columbia, include Merocanites rileyi n. sp., Imitoceras tardum n. sp.,
Irinoceras bamberi n. sp., Goniocycloides ochakensis n. gen. et sp., Polaricyclus canadensis n. sp., Eurites kusinae n. sp., Dzhaprakoceras belcourtense n. sp., D. crassum n. sp. and Furnishoceras heterolobatum n. gen. et sp. The ammonoids generally resemble faunas from the
Fascipericyclus-Ammonellipsites Zone, particularly those from the Tournaisian-Viséan boundary beds in the Chadian of the United Kingdom. To some extent however, the age of the ammonoid beds in British Columbia is refined or constrained by other associated faunal groups. The ammonoids are
directly associated with upper Scaliognathus anchoralis-Doliognathus latus Zone conodonts that indicate correlation with the upper part of the middle Osagean Burlington Formation in the Mississippi Valley. Further, the ammonoid beds are underlain and overlain by strata containing representatives of
the definitive Viséan foraminifer Eoparastaffella with a subangular to angular outer periphery - that is, morphotype 2.

The lower member, a coeval correlative of the Wileman Member of the Mount Head Formation of southwestern Alberta, was deposited on the northwest-trending Sukunka Uplift, of block-fault origin. Recessive carbonates and siliciclastics of the lower member generally overlie the upper Tournaisian to
lower Viséan Turner Valley Formation conformably, and are abruptly overlain by the lower Viséan Baril Member of the Mount Head Formation.

The microbial carbonate mounds occur as isolated deposits between 2 and 8 m thick and as complexes of small buildups developed in shallow-neritic settings. Enclosing facies in the lower member are of peritidal-marsh to neritic-shelf origin.
Lithology, mineralogy, and geochemistry of glacial sediments overlying kimberlite at Smeaton, Saskatchewan
Authors: Thorleifson L H , Garrett R G
Published: January 2016

Quaternary glacial sediments over 100 m thick overlie interbedded Cretaceous shale and extrusive kimberlite debris at a site near Smeaton, Saskatchewan. These sediments consist of diamicts interpreted as till, with minor sand, silt, and clay interbeds. The
uppermost sediments, 34.6 m thick, contain few kimberlite indicator minerals, but are rich in shield debris, thus resembling, in composition, northerly-derived till that occurs at surface throughout the region between the exposed shield and the North Saskatchewan and Saskatchewan rivers. Underlying
sediments, 33.6 m thick, contain numerous kimberlite indicator minerals, and are carbonate rich to very carbonate rich, resembling in composition northeasterly to easterly derived surface till throughout the region south of the Saskatchewan River and east of The Missouri Coteau. The lowermost
sediments, 32.2 m thick, contain few kimberlite indicator minerals, but contain both shield and carbonate erratics in intermediate amounts, and are thus of an approximately northeasterly derivation.
Las prácticas pedagógicas y la incorporación de la computadora en el aula: Una experiencia desde el programa "Una computadora por niño (Paraguay)"
Authors: Misiego Telesca Patricia Alejandra , Demelenne Dominique
Published: January 2016

Esta investigación analiza  el cambio en las interacciones entre el docente y sus estudiantes a partir de la incorporación de la computadora en aula. El estudio realiza entrevistas y observaciones de clase y sus hallazgos dan cuenta de cambios en las interacciones pedagógicas, los procesos de socialización, los procesos cognitivos y las competencias digitales de los estudiantes.
El aprendizaje en los docentes y su integración a la práctica de aula
Authors: Salazar José Michel
Published: January 2016

El presente artículo tiene como propósito estudiar cómo se produce el aprendizaje en los docentes y su integración a la práctica de aula, además corresponde a una investigación mayor centrada en la Formación Docente Continua y la Práctica Pedagógica como Estudio de Caso. Los actores son profesoras del sistema escolar municipal. El estudio de esta temática no pretende ser un análisis cognitivo, sino que un conocimiento y comprensión de la propia realidad de los docentes y sus experiencias de aula. Este aprendizaje docente emergió de los datos de las Entrevistas en profundidad, que fueron analizadas con el Método Comparativo Constante de Glasser y Strauss. Su aprendizaje, las profesoras, lo sistematizan como una herramienta, una teoría, una concepción instrumental, lo que toma de la teoría es lo que le permite el desarrollo instrumental de la clase; un medio, a partir de las propias opiniones y percepciones.
El reto de la formación docente para el desarrollo de una metodología ubicua en la Educación Superior
Authors: Vázquez-Cano Esteban
Published: January 2016

En este artículo se presenta una investigación en la que se analiza la percepción del profesorado sobre el uso didáctico de los dispositivos digitales móviles y la necesidad de procesos formativos para su correcta adecuación en la Educación Superior. A través de una metodología cuantitativa, se analiza qué tipo de actividades pueden resultar más beneficiosas para el desarrollo de procesos de enseñanza ubicuos y qué necesidades formativas son más acusadas entre el profesorado dependiendo de la modalidad formativa en la que imparte docencia y los años de experiencia. Los resultados muestran que el profesorado con menor experiencia docente percibe mayor funcionalidad didáctica en el uso de los dispositivos digitales móviles en comparación con el profesorado más experimentado; por el contrario, el profesorado más experimentado precisa de una mayor formación para el empleo educativo de los dispositivos digitales móviles.
Una propuesta de análisis de las ayudas formativas en un programa basado en actividades de modelado en educación infantil
Authors: Méndez Alarcón Claudia Myrna , Colomina Álvarez Rosa María
Published: January 2016

El trabajo estudia la actividad conjunta de modelado entre formadores/as y profesores/as en un programa de formación para la mejora de la práctica docente inclusiva en educación infantil. El objetivo es comprender cómo los formadores/as ayudan a los profesores/as mediante la construcción de la actividad conjunta en el traspaso del control del aprendizaje. El estudio propone una relectura desde la formación de una perspectiva socioconstructivista de la ayuda educativa (Coll, 2001) y asume el modelado como elemento clave para el aprendizaje sobre la enseñanza (Korthagen, Loughran & Russell, 2006). La metodología es cualitativa (Flick, 2004) y de estudio de casos (Yin, 2006). Los resultados muestran la potencialidad formativa del programa vinculada a la diversidad de actividades creadas para conseguir objetivos individualizados de mejora de la práctica del profesor/a, y la posibilidad de mantener las ayudas formativas durante el curso escolar.
Ser Profesor Universitario, desafío digno de ser emprendido…
Authors: Laudadío Julieta
Published: January 2016

Actualmente, somos testigos del derrumbamiento del prestigio y autoridad docente. Son temas que requieren atención no solo de quienes administran las políticas educativas; sino también de los mismos educadores en aras de valorar adecuadamente su profesión desde la compleja responsabilidad y exigencias de la tarea educativa. El presente trabajo reflexiona acerca del ser profesor universitario y los retos que envuelve su ejercicio en vistas a la formación integral de los estudiantes. Se analizan las implicancias de la búsqueda de la verdad y el cultivo del saber docente en su unidad y diversidad. Finalmente, se concluye que ser profesor universitario es plantearse y replantear las cuestiones fundamentales de la verdad del ser, en la búsqueda de lo perenne y transitorio del enseñar porque la tarea educativa es una aventura digna de ser emprendida.
Capacidades didácticas en el diseño de tareas con modelación matemática en la formación inicial de profesores.
Authors: Ortiz Buitrago José , Mora Zuluaga Angela
Published: January 2016

Se analiza el desarrollo de la competencia de planificación de la enseñanza relacionada con la integración de la modelación en el diseño de tareas. Se llevó a cabo un estudio cualitativo con perspectiva teórica interpretativa. La información fue recabada durante la implementación de un programa formativo, donde participaron 27 profesores de matemáticas en formación, quienes abordaron el diseño de tareas con modelación. Se recurrió a procesos de observación y análisis sobre las producciones, presentaciones y una entrevista. Los resultados permitieron identificar el desarrollo de capacidades asociadas con la integración de la modelación en el diseño de tareas. Adicionalmente, permiten afirmar que los profesores en formación desarrollaron una visión funcional sobre esta estrategia. Las dificultades se relacionaron con el diseño de tareas, los usos de la modelación en el aula, y el modelo de formación previo, al cual se asoció la ausencia de experiencias con el uso didáctico de esta estrategia.
La práctica del profesor de Ciencias: Significados personales y experiencias de profesores en formación
Authors: Vanegas Ortega Carlos Mario , Correa Molina Enrique , Fuentealba Jara Adrián Rodrigo
Published: January 2016

En este artículo se caracterizan los significados que profesores de ciencias en formación le otorgan a la práctica pedagógica y las experiencias que van marcando su desarrollo profesional docente. A través de entrevistas en profundidad y mapeos de significado personal con practicantes de diferente nivel de formación de un programa de pedagogía en biología y ciencias, se encontró que el conjunto de significados sobre la práctica están determinados por las interacciones con estudiantes y profesores, la integración de conocimientos, valores, sentimientos y emociones, y el desarrollo de la identidad profesional. Además, se estableció que, para los participantes de este estudio, las experiencias más importantes de la práctica se presentan durante el primer año de formación, y las menos gratificantes están asociadas a los profesores guías (de la escuela o liceo).
Eficacia de un programa conjunto de desarrollo de la inteligencia emocional para padres e hijos con TDAH
Authors: Fontana Abad Mónica , Ávila Jiménez Zahra
Published: January 2016

El objetivo de esta investigación es evaluar la eficacia de un programa de Inteligencia Emocional para padres e hijos con TDAH, al mismo tiempo que se estudia si existen diferencias significativas entre autopercepción de los niños con TDAH acerca de su Inteligencia Emocional y la percepción de sus padres. Para ello se ha realizado un estudio no experimental pretest-postest, para el que se han elaborado instrumentos de medida y un programa de desarrollo de la Inteligencia Emocional para padres e hijos con TDAH. Los resultados permiten afirmar que existen diferencias significativas entre la autopercepción de los niños y la percepción de sus padres. En lo que respecta al programa, ha resultado ser especialmente efectivo en lo referente a las dimensiones de reconocimiento de las propias emociones, control emocional, identificación de expresiones faciales emocionales e identificación de emociones ajenas.
Apropiación tecnológica:Una visión desde los modelos y las teorías que la explican
Authors: Fernández Morales Katiuska , McAnally Salas Lewis , Vallejo Casarín Alma
Published: January 2016

Cuando se trata de explicar la base epistemológica del término apropiación tecnológica, es necesario conducir la búsqueda hacia los modelos que se han ido construyendo en torno al tema con base en las teorías de otras áreas del conocimiento que han sido adaptadas para satisfacer las necesidades de los investigadores. En esta revisión bibliográfica, se abordan dos tradiciones psicológicas que ayudan a entender el concepto de apropiación tecnológica desde distintas perspectivas: la corriente sociocultural y la psicosocial; se explica el origen; cómo ha sido relacionado el término con otros sinónimos y las razones por las que se considera una herramienta sociocultural. Cuando se profundiza en la corriente psicosocial, se mencionan las variables estudiadas en cada uno de los diez modelos y teorías que se exponen en esta tradición, ya que sirven para visualizar los factores que intervienen en la apropiación tecnológica de los individuos.
Alumnado con necesidades específicas de apoyo educativo: Aspectos psicopedagógicos en un marco inclusivo
Authors: Luque-Parra Diego Jesús , Luque-Rojas María Jesús
Published: January 2016

En este documento, se trata de hacer un análisis pedagógico y psicoeducativo sobre las Necesidades Específicas de Apoyo Educativo, elementos de interés dentro de un ámbito inclusivo, tanto en su valor de filosofía educativa, como en la intervención psicopedagógica y en la operatividad del desarrollo curricular, núcleo fundamental de trabajo de los Psicólogos Educativos, Pedagogos, Profesores Especialistas y Profesores-Tutores. Se persigue llamar la atención sobre los profesionales y agentes educativos en torno a ello, animándoles a un pensamiento-acción en su labor, favoreciendo el desarrollo de creencias positivas hacia la inclusión, como vector de fuerza hacia procesos de enseñanza y aprendizaje ajustados y con éxito.
El proyecto curricular de la Dictadura Cívico-Militar en Chile (1973 - 1990)
Authors: Cabaluz Ducasse Jorge Fabian
Published: January 2016

El artículo elaborado desde la historia del currículum, pretende aproximarse a la comprensión del proyecto curricular impulsado por la Dictadura Cívico-Militar en Chile. Para ello, se analizan tres momentos de las políticas educativas y curriculares del Gobierno dictatorial: Un primer momento, asociado a procesos de coerción, represión y ruptura (1973-1979), una segunda etapa signada por la flexibilidad curricular y el currículum centrado en la persona (1980 - 1989) y un tercer momento caracterizado por la LOCE, el amarre y las proyecciones curriculares del régimen. Finalmente, se sintetizan y formulan reflexiones generales sobre el proyecto curricular configurado tras diecisiete años de Gobierno.
La pedagogía social en la vida cotidiana de los jóvenes: Problemáticas específicas y alternativas de futuro en un mundo globalizado
Authors: Caride Gómez José  Antonio , Varela Crespo Laura
Published: January 2016

El artículo sitúa sus argumentos en los desafíos que la Pedagogía Social debe asumir para incrementar el protagonismo cívico de los jóvenes en el mundo globalizado que habitamos, poniendo énfasis en sus realidades cotidianas. Considerando los múltiples significados que supone ser joven en una sociedad de redes, se analizan cinco transiciones clave para una (re)lectura pedagógica-social de la condición juvenil: de objetos de atención a sujetos de la acción social; del enfoque de las necesidades a la reivindicación de las capacidades; de la educación al trabajo como derechos fundamentales; de la dependencia familiar al quehacer cívico; de actores individuales a constructores de redes sociales. En este marco, se formulan propuestas orientadas a la generación de nuevas oportunidades pedagógicas y sociales para los jóvenes, plenamente partícipes -en su condición de ciudadanos libres y responsables- en la construcción de un mundo más sostenible, justo y equitativo.
Un estudio discursivo de la identidad de profesores de matemática en formación de posgrado
Authors: Molfino Vigo Verónica , Ochoviet Filgueiras Cristina
Published: January 2016

En el marco de un curso de formación de posgrado, identificamos algunos aspectos que podrían estar incidiendo en la configuración de la identidad de profesores de Matemática. Desde la perspectiva de Sfard y Prusak (2005a,  2005b) analizamos las bitácoras de seis docentes realizadas a lo largo del curso, atendiendo a aspectos que dieran pautas sobre la identidad designada y real, y a una posible transición entre ellas a partir de los contenidos abordados. Observamos que los cambios en la identidad se corresponden, fundamentalmente, con la dimensión que priorizan los profesores en sus clases: el aprendizaje o los objetos matemáticos.
Magnetohydrodynamic Natural Convection in a Rotating Enclosure
Authors: Saleh H. , Hashim I.
Published: January 2016

Magnetohydrodynamic natural convection heat transfer in a rotating, differentially heated enclosure is studied numerically in this article. The governing equations are in velocity, pressure and temperature formulation and solved using the staggered grid arrangement together with MAC method. The governing parameters considered are the Hartmann number, 0≤Ha≤70, the inclination angle of the magnetic field, 0°≤θ 90°, the Taylor number, 8.9 x 104≤Ta≤1.1 x 106 and the centrifugal force is smaller than the Coriolis force and the both forces were kept below the buoyancy force. It is found that a sufficiently large Lorentz force neutralizes the effect of buoyancy, inertial and Coriolis forces. Horizontal or vertical direction of the magnetic field was most effective in reducing the global heat transfer.
Brittle and Ductile Character of Amorphous Solids
Authors: Lagos Miguel , Das Raj
Published: January 2016

Common silicate glasses are among the most brittle of the materials. However, on warming beyond the glass transition temperature Tg glass transforms into one of the most plastic known materials. Bulk metallic glasses exhibit similar phenomenology, indicating that it rests on the disordered structure instead on the nature of the chemical bonds. The micromechanics of a solid with bulk amorphous structure is examined in order to determine the most basic conditions the system must satisfy to be able of plastic flow. The equations for the macroscopic flow, consistent with the constrictions imposed at the atomic scale, prove that a randomly structured bulk material must be either a brittle solid or a liquid, but not a ductile solid. The theory permits to identify a single parameter determining the difference between the brittle solid and the liquid. However, the system is able of perfect ductility if the plastic flow proceeds in two dimensional plane layers that concentrate the strain. Insight is gained on the nature of the glass transition, and the phase occurring between glass transition and melting.
Noise Prediction in Subsonic Flow Using Seventh-Order Dissipative Compact Scheme on Curvilinear Mesh
Authors: Mao Meiliang , Jiang Yi , Deng Xiaogang , Liu Huayong
Published: January 2016

In this paper, we investigate the performance of the seventh-order hybrid cell-edge and cell-node dissipative compact scheme (HDCS-E8T7) on curvilinear mesh for noise prediction in subsonic flow. In order to eliminate the errors due to surface conservation law (SCL) is dissatisfied on curvilinear meshes, the symmetrical conservative metric method (SCMM) is adopted to calculate the grid metric derivatives for the HDCS-E8T7. For the simulation of turbulence flow which may have main responsibility for the noise radiation, the new high-order implicit large eddy simulation (HILES) based on the HDCS-E8T7 is employed. Three typical cases, i.e., scattering of acoustic waves by multiple cylinder, sound radiated from a rod-airfoil and subsonic jet noise from nozzle, are chosen to investigate the performance of the new scheme for predicting aeroacoustic problem. The results of scattering of acoustic waves by multiple cylinder indicate that the HDCS-E8T7 satisfying the SCL has high resolution for the aeroacoustic prediction. The potential of the HDCS-E8T7 for aeroacoustic problems on complex geometry is shown by the predicting sound radiated from a rod-airfoil configuration. Moreover, the subsonic jet noise from nozzle has been successfully predicted by the HDCS-E8T7.
Bell Polynomials to the Kadomtsev-Petviashivili Equation with Self-Consistent Sources
Authors: Deng Shufang
Published: January 2016

Bell Polynomials play an important role in the characterization of bilinear equation. Bell Polynomials are extended to construct the bilinear form, bilinear Bäckhand transformation and Lax pairs for the Kadomtsev-Petviashvili equation with self-consistent sources.
Uniform Convergence Analysis of a Higher Order Hybrid Stress Quadrilateral Finite Element Method for Linear Elasticity Problems
Authors: Bai Yanhong , Wu Yongke , Xie Xiaoping
Published: January 2016

This paper derives a higher order hybrid stress finite element method on quadrilateral meshes for linear plane elasticity problems. The method employs continuous piecewise bi-quadratic functions in local coordinates to approximate the displacement vector and a piecewise-independent 15-parameter mode to approximate the stress tensor. Error estimation shows that the method is free from Poisson-locking and has second-order accuracy in the energy norm. Numerical experiments confirm the theoretical results.
Study of Heat Transfer Control with Magnetic Field Using Higher Order Finite Difference Scheme
Authors: Sivakumar R. , Vimala S. , Damodaran S. , Sekhar T. V. S.
Published: January 2016

The control of convective heat transfer from a heated circular cylinder immersed in an electrically conducting fluid is achieved using an externally imposed magnetic field. A Higher Order Compact Scheme (HOCS) is used to solve the governing energy equation in cylindrical polar coordinates. The HOCS gives fourth order accurate results for the temperature field. The behavior of local Nusselt number, mean Nusselt number and temperature field due to variation in the aligned magnetic field is evaluated for the parameters 5≤Re≤40, 0≤N≤20 and 0.065≤Pr≤7. It is found that the convective heat transfer is suppressed by increasing the strength of the imposed magnetic field until a critical value of N, the interaction parameter, beyond which the heat transfer increases with further increase in N. The results are found to be in good agreement with recent experimental studies.
Elastic-Plastic Analysis for Functionally Graded Thick-Walled Tube Subjected to Internal Pressure
Authors: Xin Libiao , Dui Guansuo , Yang Shengyou , Liu Ying
Published: January 2016

The elastic-plastic response of the functionally graded thick-walled tube subjected to internal pressure is investigated by using the relation of the volume average stresses of constituents and the macroscopic stress of composite material in micromechanics. The tube consists of two idealized isotropic elastic-plastic materials whose volume fractions are power functions of the radius. As the internal pressure increases, the deformations of one phase and two phases from elastic to plastic are analyzed. In order to simplify the calculations we assume both materials with the same Poisson's ratio. By using the assumption of a uniform strain field within the representative volume element and the Tresca yield criterion, the theoretical solutions are obtained for the case of two elastic phases and the case of two plastic phases, and the function of the radial displacement is presented for the case with both elastic and plastic phases. The yield criterion of functionally graded material is given in terms of the yield stresses and volume fractions of constituents rather than Young's modulus and yield stress with different unknown parameters of the whole material in the existing papers. Finally we also discuss the position where the plastic deformation first occurs and the conditions for which material first yields in the tube.
Distributed Control of the Stochastic Burgers Equation with Random Input Data
Authors: Lee Hyung-Chun , Nam Yun
Published: January 2016

We discuss a control problem involving a stochastic Burgers equation with a random diffusion coefficient. Numerical schemes are developed, involving the finite element method for the spatial discretisation and the sparse grid stochastic collocation method in the random parameter space. We also use these schemes to compute closed-loop suboptimal state feedback control. Several numerical experiments are performed, to demonstrate the efficiency and plausibility of our approximation methods for the stochastic Burgers equation and the related control problem.
Traffic Lights or Roundabout? Analysis using the Modified Kinematic LWR Model
Authors: Pudjaprasetya S. R. , Bunawan J. , Novtiar C.
Published: January 2016

Traffic flow is treated as a continuum governed by the kinematic LWR model and the Greenshield flux function. The model is modified to describe traffic flow on a road with traffic lights or a roundabout. Parameters introduced determine the traffic flow behaviour and queue formation, and numerical simulations based on the Godunov method are carried out. The numerical procedure is shown to converge, and produces results consistent with previous analytic results.
Integrating Feature Direction Information with a Level Set Formulation for Image Segmentation
Authors: Li Meng , Zhan Yi
Published: January 2016

A feature-dependent variational level set formulation is proposed for image segmentation. Two second order directional derivatives act as the external constraint in the level set evolution, with the directional derivative across the image features direction playing a key role in contour extraction and another only slightly contributes. To overcome the local gradient limit, we integrate the information from the maximal (in magnitude) second-order directional derivative into a common variational framework. It naturally encourages the level set function to deform (up or down) in opposite directions on either side of the image edges, and thus automatically generates object contours. An additional benefit of this proposed model is that it does not require manual initial contours, and our method can capture weak objects in noisy or intensity-inhomogeneous images. Experiments on infrared and medical images demonstrate its advantages.
Modelos matemáticos en un problema de epidemias
Authors: Vidal Meló Anna
Published: January 2016

<span style="line-height: 120%; font-family: 'Times New Roman','serif'; font-size: 10pt; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: ES; mso-fareast-language: ES; mso-bidi-language: AR-SA;">La introducción de conceptos matemáticos a través del desarrollo y estudio de modelos ha sido tratado en numerosos trabajos. La introducción de los modelos suele hacerse básicamente desde el discurso del professor y el trabajo del alumno suele reducirse a la experimentación con el modelo dado. La aproximación a un problema mediante modelos IBM (Individual Based Model) resulta más comprensible para el alumno, permite justificar y complementar otras aproximaciones a la solución (modelos diferenciales continuos y/o modelos discretos). En este trabajo se presenta una experiencia docente basada en afrontar un mismo problema mediante enfoques complementarios en base a modelos continuos, discretos e IBM. Finalmente se presenta una propuesta metodológica para ponerla en práctica utilizando el Aprendizaje Cooperativo y el Problem/Project Based Learning.
Diseño e implementación de tareas de modelización con iPad®'s: un enfoque dual
Authors: Diago Nebot Pascual David , Ortega Pons Miriam , Puig Espinosa Luis , Ferrando Palomares Irene
Published: January 2016

En este trabajo presentamos el diseño de dos propuestas para introducir la modelización de fenómenos físicos a través de actividades de modelización asistidas mediante iPad's. Cada una de las propuestas que vamos a presentar tiene una visióon de la modelización: en un caso se trata de utilizar la modelización como vehículo para introducir contenidos matemáticos concretos mientras que, en el otro, pretendemos desarrollar una actividad que ayude a los alumnos a poner en marcha la competencia en resolución de problemas a través de la modelización. El objetivo es proporcionar dos propuestas basadas en la modelización dando detalles suficientes para que éstas puedas ser implementadas en un aula de último curso de ESO o primer curso de Bachillerato.
WAVEFRONT TESTER: Un nuevo laboratorio virtual para el estudio de los sensores frente de onda.
Authors: Ferrando Martín Vicente , Remón Martín Laura , Furlan Walter D. , Giménez Fernando , Monsoriu Juan A.
Published: January 2016

Se presenta un laboratorio virtual desarrollado en MATLAB GUI (Graphical User Interface) para ser utilizado en la asignatura de "Tecnología de Sensores Optoelectrónicos" que se imparte en  "Escuela Técnica Superior de Ingeniería del Diseño" de la Universitat Politècnica de València. El objetivo de este laboratorio es servir de herramienta informática para el estudio de un sensor Shack Hartman y los parámetros que determinan el rango dinámico del mismo en la medida de las aberraciones. Se presentan distintos ejemplos realizados con diferentes aberraciones (desenfoque, astigmatismo, coma) y para diferentes configuraciones del sensor.
Análisis del funcionamiento del motor y de la eficiencia de conducción mediante el uso de sistemas GPS y OBD
Authors: Guardiola García Carlos , Dolz Ruiz Vicente , Pla Moreno Benjamín , Reig Bernad Alberto
Published: January 2016

El uso generalizado de los teléfonos inteligentes y la disponibilidad de sensores de diagnóstico de abordo (OBD) permite su uso como herramientas para mejorar la forma en que los estudiantes de ingeniería aprenden como los Motores de Combustión Interna Alternativos operan en condiciones de conducción reales. En particular, la metodología de aprendizaje presentada en este artículo se basa en proporcionar a los estudiantes un sensor OBD de bajo coste que en combinación con sus propios teléfonos inteligentes les permite registrar las variables del motor y del vehículo durante sus viajes diarios. Posteriormente, los estudiantes analizan el comportamiento de sus motores, con especial énfasis en el consumo de combustible y la huella de CO2 de sus patrones de conducción, para finalmente  evaluar el potencial de diferentes arquitecturas de sistema de propulsión. La experiencia muestra que el trabajo experimental y el hecho de que los alumnos analicen sus propios hábitos y estilos de conducción despierta su interés en la materia.
Uncertainty: A Diagrammatic Treatment
Authors: Dow Sheila
Published: January 2016

The purpose of this paper is to clarify the difference between the mainstream and Keynesian understandings of uncertainty which persists in spite of superficial similarities. It is argued that the difference stems from the mainstream habit of thinking in terms of a full-information benchmark, where uncertainty arises from incomplete information. Degrees of uncertainty (or ambiguity) refer to the quantifiable extent of incompleteness. In contrast, Keynesian uncertainty cannot, even in principle, be eliminated. By treating uncertain knowledge as the norm, Keynesian uncertainty theory analyses differing degrees of uncertainty in relation to grounds for belief and thus considers the cognitive role of institutions and conventions in influencing the degree of uncertainty. The paper offers a simple diagrammatic representation of these differences, and illustrates its use with different depictions of the crisis, its aftermath and the policy response appropriate to each understanding.
Teaching Transformational Leadership to Undergraduate Agricultural Leadership Students: Using the Personality Trait of Agreeableness To Improve Understanding
Authors: Lamm Kevan W. , Carter Hannah S. , Stedman Nicole L. P , Lamm Alexa J.
Published: January 2016

Training undergraduate agricultural students to be strong, positive leaders will have a large impact on the industries they work within and therefore should be of utmost importance to agricultural educators. Transformational leaders (TL) tend to have higher performing, more satisfied teams; consequently, development of TL characteristics should result in a more productive future workforce. The personality trait of agreeableness has been associated with the interpersonal aspects of leadership; however, the literature is unclear whether agreeableness is a significant predictor of TL. The purpose of this study was to examine the relationships between the personality trait agreeableness and TL in undergraduate agricultural leadership students. The findings indicated the facets of agreeableness had more predictive power on TL than the broader trait of overall agreeableness. Recommendations include framing TL development in a personality context. When discussing personality, a review of the facets of agreeableness should result in more meaningful learning for participants.