New understanding of the shape-memory response in thiol-epoxy click systems: towards controlling the recovery process

Our research group has recently found excellent shape-memory response in “thiol-epoxy” thermosets obtained with click-chemistry. In this study, we use their well-designed, homogeneous and tailorable network structures to investigate parameters for better control of the shape-recovery process. We present a new methodology to analyse the shape-recovery process, enabling easy and efficient comparison of shape-memory experiments on the programming conditions. Shape-memory experiments at different programming conditions have been carried out to that end. Additionally, the programming process has been extensively analysed in uniaxial tensile experiments at different shape-memory testing temperatures. The results showed that the shape-memory response for a specific operational design can be optimized by choosing the correct programming conditions and accurately designing the network structure. When programming at a high temperature (T » Tg), under high network mobility conditions, high shape-recovery ratios and homogeneous shape-recovery processes are obtained for the network structure and the programmed strain level (eD). However, considerably lower stress and strain levels can be achieved. Meanwhile, when programming at temperatures lower than Tg, considerably higher stress and strain levels are attained but under low network mobility conditions. The shape-recovery process heavily depends on both the network structure and eD. Network relaxation occurs during the loading stage, resulting in a noticeable decrease in the shape-recovery rate as eD increases. Moreover, at a certain level of strain, permanent and non-recoverable deformations may occur, impeding the completion and modifying the whole path of the shape-recovery process.Postprint (author's final draft

La construcción de un espacio de resistencia urbano. Crear y re-crear formas de contestar al poder: Entrevista con Madrilonia

Entrevista con Madrilonia

Elbe, Stefan, Virus Alert: Security, Governmentality, and the AIDS Pandemic, Columbia University Press, 2009

Reseña de: ELBE, Stefan, Virus Alert: Security, Governmentality, and the AIDS Pandemic, Columbia University Press, 200

Sentimientos extremos ante una realidad extrema: Del traslado del conflicto a la construcción de símbolos

Reseñas de: - Le Carré, John, El jardinero fiel, Ed. Random House Mondadori S.A. Barcelona, 2001 - Mankell, Henning, El cerebro de Kennedy, Ed. Tusquets, Barcelona, 200

Promoción de la salud en infecciones de trasmisión sexual entre mujeres que tienen sexo con mujeres y mujeres que tienen sexo con mujeres y hombres.

Existen pocos estudios sobre las Infecciones de Trasmisión Sexual (ITS) entre Mujeres que tienen Sexo con Mujeres (MSM). Conocer los comportamientos de riesgo y la trasmisión de las ITS permitiría ofrecer programas de promoción de la salud y prevención de ITS en este colectivo, así como conocer la repercusión que todo ello supone en términos de salud para la mujer. MATERIAL Y MÉTODOS – Estudio transversal realizado durante el mes de noviembre de 2016 en una muestra de 170 MSM y MSMH procedentes de todo el territorio español basado en la auto-cumplimentación de un cuestionario online generado a través de la plataforma Google Doc. Posteriormente se realizó un análisis descriptivo de los resultados. RESULTADOS– La mitad de la muestra del estudio no tiene información sobre las ITS que se dan entre MSM y hay una gran proporción que nunca se ha realizado un screening de ITS La gran mayoría no usa métodos de barrera en sus relaciones sexuales con mujeres, tiene relaciones sexuales durante la menstruación y comparte juguetes sexuales. Hay un desconocimiento generalizado de la variedad de métodos de barrera existentes en relaciones sexuales entre mujeres. CONCLUSIONES – Algunas de las conclusiones que refuerzan la necesidad de promoción de la salud en ITS entre MSM y MSMH son el uso casi inexistente de métodos de barrera durante las relaciones sexuales, y la baja accesibilidad a los mismos. Las relaciones sexuales durante la menstruación, el uso compartido de juguetes sexuales, sexo oral-anal y estimulación de clítoris con nalgas o ano son algunas de las prácticas de riesgo entre MSM. Es necesaria la formación del colectivo médico en materia de trasmisión de ITS entre MSM, prácticas sexuales de riesgo y métodos de barrera, de forma que los pacientes reciban información de una fuente fidedigna. Actualmente esta información se adquiere a través de internet, con el sesgo que esto implica.Grado en Medicin

Dynamics and control of acrobatic kites

In this Bachelor Thesis a model of a kite linked by two wires has been developed. The kite is a rigid solid, exibility is not considered, and the wires are inextensible and their mass negligible. The difference of present model with the one used by [5] is that this kite is attached at two different points by two wires joined to the ground station in the other end. Wires' initial length is going to play an important role when finding dimensionless variables. They can be used to control the kite with respect to time, but in this Bachelor Thesis, this situation is not considered. This project is divided in different sections which explain step by step the kite model, the equations of motion and the stability of the kite at equilibrium. Kite model and shape have been explained and analysed. Kite shape coincides with the one used by [5] and it is build up by chord, span and height. Center of mass of kite must be located by using kite parameters and also its mass. Kite can be placed in the space with parameters and position of center of mass. Center of mass is the origin of the body frame, which is reached from earth fixed reference frame after 4 rotations (going through auxiliary frames), the 4 angles corresponding to the state vector and the degrees of freedom (6 dof of a rigid body minus two constraints). Control vector, which is not used in a time dependent way in this Bachelor Thesis, is also calculated being time dependent. Solid kinematics have been developed by calculating angular velocities associated to the different rotations, position vector of the center of mass with respect to the inertial earth frame and also velocity vector, by deriving position vector with respect to time in earth frame. In next section equations of motion are going to be discuss. Center of mass acceleration was not calculated because the used formulation is the Lagrangian, and it does not use accelerations. This formulation is also characterized because of the elimination of traction forces. Lagrangian function is composed by kinetic and potential energy. Kinetic energy is given by linear and angular velocities; potential energy can be calculated from position vector. From Lagrangian formulation, equations of motion can be calculated. Finally, for studying the stability of the kite, equilibrium positions must be calculated. They come up after solving equations of motion using Newton's method, assuming some statements. At this equilibrium point the problem must be analysed and Jacobian is obtained. The Jacobian is a matrix to which eigenvalue problem is applied. For finding the stability boundary in terms of wind velocity, real part of eigenvalues is plotted versus different values of wind velocity. The point at which real part of all eigenvalues become negative, is the one that sign the stability limit. An analysis in the stable region is also performed, solving the eigenvalue problem and finding the different modes which explain the behaviour of the kite in that equilibrium point at some stable velocity. For finishing the complete study of stability, the response of the kite after a perturbation from the equilibrium point is analysed in stable and unstable region, finding that in stable region, motion tends to be convergence and in unstable region, motion will be divergence.Ingeniería Aeroespacia