Search results for "mechanical engineering"
showing 10 items of 4245 documents
Fibre fragment distribution in a single-fibre composite tension test
2001
Abstract Single fibre fragmentation tests are performed for brittle fibres with Weibull strength distribution and different surface treatments. The fragmentation process is modelled and closed-form expressions for break spacing distribution are obtained. The model accounts for the effect of finite fibre length on the initial fragmentation as well as for break interaction on the advanced fragmentation stage. It is assumed that the exclusion zone due to fibre–matrix interface failure and stress recovery in the fibre is linearly dependent on the applied load. This assumption is validated experimentally. The derived theoretical average fragment length dependence on applied load is used to deter…
Time resolved emission at 1.3 μm of a single InAs quantum dot by using a tunable fibre Bragg grating
2013
Photoluminescence and time resolved photoluminescence from single metamorphic InAs/GaAs quantum dots (QDs) emitting at 1.3 mu m have been measured by means of a novel fibre-based characterization set-up. We demonstrate that the use of a wavelength tunable fibre Bragg grating filter increases the light collection efficiency by more than one order of magnitude as compared to a conventional grating monochromator. We identified single charged exciton and neutral biexciton transitions in the framework of a random population model. The QD recombination dynamics under pulsed excitation can be understood under the weak quantum confinement potential limit and the interaction between carriers at the …
Dissimilar titanium-aluminum skin-stringer joints by FSW: process mechanics and performance
2022
Ever since its inception, friction stir welding (FSW) is being validated by scientific investigations as an effective substitution for fusion-based conventional joining technologies. One of the main strengths of FSW is the possibility to produce dissimilar joints, even using materials extremely different in terms of thermal and mechanical properties. The goal of the present research is to investigate the feasibility of both Al-Ti skin-stringer and reversed Ti-Al skin-stringer joints, highlighting the effect of joint configuration and main process parameters on material flow and joint mechanical properties. During the investigation, the essentiality of the proper heat input through balancing
Imagem corporal positiva e redes sociais na população adulta da área metropolitana de Buenos Aires
2021
Resumen: La imagen corporal positiva presenta una función protectora preeminente ante los medios de comunicación actuales, sin embargo, a la fecha no se cuenta con estudios que la vinculen con las redes sociales. El objetivo de este trabajo fue estudiar la asociación entre la motivación y usos de redes sociales y la imagen corporal positiva, considerando diferencias por sexo y grupos de edad. La muestra contó con 180 participantes, 94 varones (52.2 %) y 86 mujeres (47.8 %), edades de 18 a 65 años (M = 31.03; DE = 13.34). Los instrumentos utilizados fueron el BAS-2 y una encuesta sobre redes sociales. La imagen corporal positiva presentó asociación negativa con dos escalas de la motivación p…
LA INCLUSIÓN DEL MÉDICO EN LA FORMACIÓN DEL INTÉRPRETE EN EL ÁMBITO SANITARIO
2017
La experiencia docente que describimos en este artículo propone la adquisición y desarrollo de destrezas interpretativas a través de cuatro sesiones teórico-prácticas sobre interpretación en los servicios públicos (ISP). Su particularidad reside en integrar a un profesional del ámbito médico-sanitario en el proceso de aprendizaje, que se perfecciona mediante role plays en el aula. Su colaboración desinteresada, activa y participativa estuvo presente desde la elección de los casos que se abordaron en clase derivados de sus experiencias con pacientes extranjeros, hasta la asunción del papel que habitualmente desempeñan en su trabajo en los ejercicios de simulación con los alumnos. La interacc…
A simple field method to measure the hydrodynamic properties of soil surface crust
2013
The hydraulic resistance of the surface crust was determined by a combination of two infiltrometric techniques: first, a surface measurement of steady-state infiltration rate is conducted by a mini-disk tension infiltrometer (MDI); then, the surface crust is removed, its thickness is measured, and a ponded infiltration test is performed at the same site. The Beerkan Estimation of Soil Transfer parameters (BEST) method is applied to estimate the hydraulic properties of the underlying soil provided the particlesize distribution and the bulk density are known. Under the assumption of a unit gradient of hydraulic head below the soil crust, the pressure head at the interface crust-soil is derive…
Ti Alloyed α-Ga2O3: Route towards Wide Band Gap Engineering
2020
The suitability of Ti as a band gap modifier for &alpha
Modelling flow and heat transfer in spacer-filled membrane distillation channels using open source CFD code
2013
Abstract A good understanding of the details of hydrodynamic and heat transport conditions and their impact on temperature polarisation and pressure drops is essential for optimum design of membrane distillation (MD) modules. To this end, the present work reports on initial progress in the development of a tool for 3D simulation of spacer-filled MD channels based on the open source CFD code library OpenFOAM. The paper discusses a number of modelling and implementation aspects including model geometry and computational domain, choice of boundary conditions, and discretisation schemes. The results pertaining to the effect of three different spacer types on the fluid dynamics and heat transfer…
Terahertz Spin‐to‐Charge Conversion by Interfacial Skew Scattering in Metallic Bilayers
2021
The efficient conversion of spin to charge transport and vice versa is of major relevance for the detection and generation of spin currents in spin‐based electronics. Interfaces of heterostructures are known to have a marked impact on this process. Here, terahertz (THz) emission spectroscopy is used to study ultrafast spin‐to‐charge‐current conversion (S2C) in about 50 prototypical F|N bilayers consisting of a ferromagnetic layer F (e.g., Ni81Fe19, Co, or Fe) and a nonmagnetic layer N with strong (Pt) or weak (Cu and Al) spin‐orbit coupling. Varying the structure of the F/N interface leads to a drastic change in the amplitude and even inversion of the polarity of the THz charge current. Rem…
Design Scheme of New Tetragonal Heusler Compounds for Spin-Transfer Torque Applications and its Experimental Realization
2012
Band Jahn-Teller type structural instabilities of cubic Mn(2)YZ Heusler compounds causing tetragonal distortions can be predicted by ab initio band-structure calculations. This allows for identification of new Heusler materials with tunable magnetic and structural properties that can satisfy the demands for spintronic applications, such as in spin-transfer torque-based devices.