1,044 research outputs found
Estudio experimental del Sistema de Albañilería Integral en la construcción de viviendas sismorresistentes. Experimental study of the Integral Masonry System in the construction of earthquake resistant houses
This paper presents the application of the Integral
Masonry System (IMS) to the construction of earthquake
resistant houses and its experimental study. To verify the
security of this new type of building in seismic areas of
the third world two prototypes have been tested, one
with adobe and the other with hollow brick. In both
cases it’s a two-story 6x6x6 m3 house built to scale 1/2.
The tests are carried out at the Laboratory of Antiseismic
Structures of the Department of Engineering,
Pontifical Catholic University of Peru in Lima, in
collaboration with the UPM (Technical University of
Madrid).
This article shows the design process of the prototypes to
test, including the sizing of the reinforcements, the
characteristics of the tests and the results obtained. These
results show that the IMS with adobe or brick remains
stable with no significant cracks faced with a severe
earthquake, with an estimated acceleration of 1.8 g.
Este artículo presenta una aplicación del Sistema de
Albañilería Integral (SAI) a la construcción de viviendas
sismorresistentes y su estudio experimental. Para verificar
su seguridad para su construcción en zonas sísmicas
del tercer mundo se han ensayado dos prototipos, uno
con adobe, y otro con ladrillo hueco. Se trata de una
vivienda de 6x6x6 m3 y dos plantas que se construyen a
escala 1/2. Los ensayos se realizaron en el Laboratorio
de Estructuras Antisísmicas del Departamento de Ingeniería
de la Pontificia Católica Universidad del Perú (PUCP)
de Lima en colaboración con la UPM (Universidad Politécnica
de Madrid).
Este artículo muestra el proceso de diseño de los prototipos
a ensayar, incluido el dimensionado de los refuerzos,
las características de los ensayos y los resultados
obtenidos. Estos resultados muestran que el SAI con
adobe o ladrillo permanece estable sin grietas significativas ante un sismo severo, con una aceleración estimada
de 1,8 g
Formation of Epitaxial MnBi Layers on (Ga,Mn)As
The initial growth of MnBi on MnAs terminated (GaMn)As is studied by means of
synchrotron based photoelectron spectroscopy. From analysis of surface core
level shifts we conclude that a continued epitaxial MnBi layer is formed, in
which the MnAs/MnBi interface occurs between As and Bi atomic planes. The well
defined 1x2 surface reconstruction of the MnAs surface in preserved for up to 2
ML of MnBi before clear surface degradation occurs.Comment: 18 pages, 5 figure
Influence of annealing parameters on the ferromagnetic properties of optimally passivated (Ga,Mn)As epilayers
The influence of annealing parameters - temperature and time - on the
magnetic properties of As-capped (Ga,Mn)As epitaxial thin films have been
investigated. The dependence of the transition temperature (Tc) on annealing
time marks out two regions. The Tc peak behavior, characteristic of the first
region, is more pronounced for thick samples, while for the second
(`saturated') region the effect of the annealing time is more pronounced for
thin samples. A right choice of the passivation medium, growth conditions along
with optimal annealing parameters routinely yield Tc-values of ~ 150 K and
above, regardless of the thickness of the epilayers.Comment: 5 pages, 3 figure
Proyecto reflexivo de co-evaluación y auto-evaluación formativa utilizando la técnica del Puzzle de Aronson dentro del Aprendizaje Cooperativo
[ES] El presente estudio tiene por objetivo la evaluación del proceso de enseñanza-aprendizaje de la educación física (EF), mediante la comparación de las percepciones del alumnado de dos cursos de primero de Bachillerato y sus dos respectivos profesores/as. Se trata de un estudio de caso, basado en técnicas de investigación cualitativas: entrevistas semiestructuradas, observación participante y general y una innovación competencial cooperativa basada en el Puzzle de Aronson. Los resultados muestran la existencia de una distancia entre la definición teórica del objetivo de la asignatura y la aplicación de esta en el aula. Este hecho se ve condicionado por limitaciones del contexto educativo, pero también por limitaciones profesionales de las cuáles no siempre se tiene consciencia.[EN] This study aims to analyze the teaching-learning process of the Physical Education (PE), by comparing the perceptions of students in first years of high school and their two respective teachers. This is a case study, based on qualitative research techniques: semi-structured interviews, participant and general observation and a research cooperative innovation based on the concept of Aronson Puzzle. The results show the existence of a gap between the theory defining the objective of the subject and the application of this in the classroom. This is conditioned by limitations of the educational context, but also by professional constraints of which we do not always have consciousness.Ahís Adell, M. (2021). Proyecto reflexivo de co-evaluación y auto-evaluación formativa utilizando la técnica del Puzzle de Aronson dentro del Aprendizaje Cooperativo. En IN-RED 2020: VI Congreso de Innovación Educativa y Docencia en Red. Editorial Universitat Politècnica de València. 1092-1103. https://doi.org/10.4995/INRED2020.2020.11984OCS1092110
La contribución del «soft law» a la no proliferación biológica y química
The new threats of the 21st century, such as the prominence of non-state actors, the new modalities of terrorism and the hazardous weapons of mass destruction, emphasise the need of a real and effective collective cooperation. Within this context, conventional mechanisms targeting biological and chemical weapons export controls do not seem to be sufficient. The role of soft law for non-proliferation purposes must be therefore considered. In particular, this study analyses how export control regimes, such as the Australia Group, the MTCR and the Wassenaar Arrangement, together with the Proliferation Security Initiative, play a significant part in the effective control of dual-use strategic items.Las nuevas amenazas del siglo XXI, entre las que se encuentran los actores no estatales, el nuevo terrorismo y las armas de destrucción masiva, acentúan la necesidad de una cooperación colectiva efectiva. En este contexto, los mecanismos convencionales vigentes para el control de las exportaciones de armamento biológico y químico no parecen ser suficientes. Es preciso entonces considerar el papel del soft law en esta materia, en particular, cómo ciertos foros informales, como el Grupo Australia, el MTCR y el Arreglo de Wassenaar, junto con la Iniciativa de Seguridad contra la Proliferación, contribuyen a un control efectivo sobre bienes estratégicos de doble uso civil y militar
Post-growth annealing of GaMnAs under As capping - an alternative way to increase Tc
We demonstrate that in situ post-growth annealing of GaMnAs layers under As
capping is adequate for achieving high Curie temperatures (Tc) in a similar way
as ex situ annealing in air or in N2 atmosphere practiced earlier.Comment: 13 pages, 4 figure
Digital Competence and Computational Thinking of Student Teachers
Digital competence is one of the most demanded skills, and includes, among other aspects, the use of technological, informational, multimedia or communication skills and knowledge. In recent years, different institutions have included computational thinking among the different areas that make up this digital competence. However, there are few publications that deepen the relationship between computational thinking and digital competence. The present study analyzes the level of digital competence and computa-tional thinking of 248 Spanish university students, exploring the relation-ships between both abilities and the existing differences. According to the results, the majority of the students perceive themselves with a medium to a high level of digital competence, highlighting the multimedia and commu-nicative dimensions, as opposed to the more technological aspects. On the other hand, there is a correlation between computational thinking and digi-tal competence, especially with the communicative and technological areas. Likewise, the results indicate that women obtain lower results in their computational thinking and are perceived to be digitally less competent than men, especially in regard to the technological dimension. These results provide relevant information in terms of research and open the door to the development of training actions in student teachers to overcome the still-existing gender gaps
Digital teaching competence of university teachers: A systematic review of the literature
The digital teaching competence is an emerging
issue in scientific literature. However, despite existence of
different frameworks that define it, most of them are focused on
the pre-university level. This article presents the results of a
systematic review of the literature on the digital teaching
competence of university teachers, in the Web of Science and
Scopus scientific databases. According to the results, university
teachers must be competent enough to meet the new challenges of
today's digital society. This digital competence, both technical
and pedagogical, allows teachers to enrich their teaching, develop
the digital competence of their students and continue to develop
professionally. Regarding their level of digital teaching
competence, most university teachers seem to have adequate
technical digital competence. Nevertheless, the results regarding
the pedagogical use of technologies are different, with lower
levels being found in the use of technologies for their own
teaching development
MnAs dots grown on GaN(0001)-(1x1) surface
MnAs has been grown by means of MBE on the GaN(0001)-(1x1) surface. Two
options of initiating the crystal growth were applied: (a) a regular MBE
procedure (manganese and arsenic were delivered simultaneously) and (b)
subsequent deposition of manganese and arsenic layers. It was shown that
spontaneous formation of MnAs dots with the surface density of 1
cm and cm, respectively (as observed by AFM),
occurred for the layer thickness higher than 5 ML. Electronic structure of the
MnAs/GaN systems was studied by resonant photoemission spectroscopy. That led
to determination of the Mn 3d - related contribution to the total density of
states (DOS) distribution of MnAs. It has been proven that the electronic
structures of the MnAs dots grown by the two procedures differ markedly. One
corresponds to metallic, ferromagnetic NiAs-type MnAs, the other is similar to
that reported for half-metallic zinc-blende MnAs. Both system behave
superparamagnetically (as revealed by magnetization measurements), but with
both the blocking temperatures and the intra-dot Curie temperatures
substantially different. The intra-dot Curie temperature is about 260 K for the
former system while markedly higher than room temperature for the latter one.
Relations between growth process, electronic structure and other properties of
the studied systems are discussed. Possible mechanisms of half-metallic MnAs
formation on GaN are considered.Comment: 20+ pages, 8 figure
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