19 research outputs found
Representaciones sociales de padres e hijos acerca del ejercicio de la parentalidad y su relación con la infancia vulnerada en sus derechos
Se trata de un estudio exploratorio, cualitativo que utiliza como encuadre teórico y metodológico la teoría de las Representaciones Sociales, aplicadas a la parentalidad, desde la mirada de padres e hijos convivientes y de padres e hijos que han sido institucionalizados por tener derechos vitales vulnerados
Experimental Validation of the Attenuation Properties in the Sonic Range of Metaconcrete Containing Two Types of Resonant Inclusions
Background: Metaconcrete is a new concept of concrete, showing marked attenuation properties under impact and blast loading, where traditional aggregates are partially replaced by resonant bi-material inclusions. In a departure from conventional mechanical metamaterials, the inclusions are dispersed randomly as cast in the material. The behavior of metaconcrete at supersonic frequencies has been investigated theoretically and numerically and confirmed experimentally.
Objective: The feasibility of metaconcrete to achieve wave attenuation at low frequencies demands further experimental validation. The present study is directed at characterizing dynamically, in the range of the low sonic frequencies, the—possibly synergistic—effect of combinations of different types of inclusions on the attenuation properties of metaconcrete.
Methods: Dynamic tests are conducted on cylindrical metaconcrete specimens cast with two types of spherical inclusions, made of a steel core and a polymeric coating. The two inclusions differ in terms of size and coating material: type 1 inclusions are 22 mm diameter with 1.35 mm PDMS coating; type 2 inclusions are 24 mm diameter with 2 mm layer natural rubber coating. Linear frequency sweeps in the low sonic range (< 10 kHz), tuned to numerically estimated inclusion eigenfrequencies, are applied to the specimens through a mechanical actuator. The transmitted waves are recorded by transducers and Fast-Fourier transformed (FFT) to bring the attenuation spectrum of the material into full display.
Results: Amplitude reductions of transmitted signals are markedly visible for any metaconcrete specimens in the range of the inclusion resonant frequencies, namely, 3,400-3,500 Hz for the PDMS coating inclusions and near 3,200 Hz for the natural rubber coating inclusions. Specimens with mixed inclusions provide a rather uniform attenuation in a limited range of frequencies, independently of the inclusion density, while specimens with a single inclusion type are effective over larger frequency ranges. With respect to conventional concrete, metaconcrete reduces up to 90% the amplitude of the transmitted signal within the attenuation bands.
Conclusions: Relative to conventional concrete, metaconcrete strongly attenuates waves over frequency bands determined by the resonant frequencies of the inclusions. The present dynamical tests conducted in the sonic range of frequencies quantify the attenuation properties of the metaconcrete cast with two types inclusions, providing location, range and intensity of the attenuation bands, which are dependent on the physical-geometric features of the inclusions
Oneiric stress and safety and security at work: the discovery of a new universal symbol
Cox and Griffiths define as psychosocial risks at work “those aspects of the
planning, organization and management of work, which, along with their
environmental and social contexts, may affect mental and physical health of the
employees, directly or indirectly producing stress”. Therefore, a more effective
approach to occupational safety and security should include integrated risk
management through the identification of any work stress related problem. The
purpose of this paper is to analyze the possible correlation of risk at work with
the modification of sleep, and inside it, the specific function of dream activity
Diferencias en las representaciones sociales de la sexualidad entre estudiantes secundarios de la provincia de Mendoza, que han recibido educación sexual “formal” y aquellos que no la han recibido
En la última década enla Argentina, conforme a la legislación vigente se ha comenzado a implementar la educación sexual en las escuelasCon la intención de conocer sobre los efectos de esas actividades educativas, surge el presente estudio de carácter cualitativo, exploratorio y descriptivo de corte psicosocial que utiliza como marco teórico la teoría de las Representaciones Sociales (RS) de Moscovici y los aportes de Abric con su propuesta metodológica.
Efectividad (adherencia) en la etapa de admisión en los centros preventivos asistenciales en adicciones en función de los estadios y procesos de cambio y variables socio-demográficas.
El estudio mide el perfil socio-demográfico, el estadio y los procesos de cambio de los pacientes que llegaron a admisión a los Centros Preventivos Asistenciales Públicos en adicciones (CPAA) y su relación con la adherencia al tratamiento al cabo de 60 días. Investigaciones indican que cuanto más avanzada está la persona en el estadio de cambio al inicio del proceso terapéutico más rápido puede predecirse el progreso. Se abordó este estudio desde el Modelo Transteórico de Prochaska y DiClemente
Experimental Validation of the Attenuation Properties in the Sonic Range of Metaconcrete Containing Two Types of Resonant Inclusions
Background: Metaconcrete is a new concept of concrete, showing marked attenuation properties under impact and blast loading, where traditional aggregates are partially replaced by resonant bi-material inclusions. In a departure from conventional mechanical metamaterials, the inclusions are dispersed randomly as cast in the material. The behavior of metaconcrete at supersonic frequencies has been investigated theoretically and numerically and confirmed experimentally. Objective: The feasibility of metaconcrete to achieve wave attenuation at low frequencies demands further experimental validation. The present study is directed at characterizing dynamically, in the range of the low sonic frequencies, the—possibly synergistic—effect of combinations of different types of inclusions on the attenuation properties of metaconcrete. Methods: Dynamic tests are conducted on cylindrical metaconcrete specimens cast with two types of spherical inclusions, made of a steel core and a polymeric coating. The two inclusions differ in terms of size and coating material: type 1 inclusions are 22 mm diameter with 1.35 mm PDMS coating; type 2 inclusions are 24 mm diameter with 2 mm layer natural rubber coating. Linear frequency sweeps in the low sonic range (< 10 kHz), tuned to numerically estimated inclusion eigenfrequencies, are applied to the specimens through a mechanical actuator. The transmitted waves are recorded by transducers and Fast-Fourier transformed (FFT) to bring the attenuation spectrum of the material into full display. Results: Amplitude reductions of transmitted signals are markedly visible for any metaconcrete specimens in the range of the inclusion resonant frequencies, namely, 3,400-3,500 Hz for the PDMS coating inclusions and near 3,200 Hz for the natural rubber coating inclusions. Specimens with mixed inclusions provide a rather uniform attenuation in a limited range of frequencies, independently of the inclusion density, while specimens with a single inclusion type are effective over larger frequency ranges. With respect to conventional concrete, metaconcrete reduces up to 90% the amplitude of the transmitted signal within the attenuation bands. Conclusions: Relative to conventional concrete, metaconcrete strongly attenuates waves over frequency bands determined by the resonant frequencies of the inclusions. The present dynamical tests conducted in the sonic range of frequencies quantify the attenuation properties of the metaconcrete cast with two types inclusions, providing location, range and intensity of the attenuation bands, which are dependent on the physical-geometric features of the inclusions. © 2020, The Author(s)
ANALYSIS OF 3D NO-TENSION MASONRY-LIKE WALLS
Modeling masonry as a linear elastic no-tension material, an original approach is implemented to analyze
3D structural elements, with special attention to walls. Masonry is replaced by a suitable equivalent
orthotropic material with spatially varying elastic properties and negligible stiffness in case of tensile
strain. An energy-based minimization problem is implemented to define the distribution and the orientation
of the equivalent material for a given compatible load, so as to obtain a compressive state of stress
throughout the structural element. A regular mesh of hexahedrons is used to speed up the sensitivity
analysis. The capabilities of the approach in predicting no-tension stress solutions in masonry walls is
shown, considering dead loads and both in-plane and out-of-plane live loads