Caracterització I Optimització De L'estabilitat Lateral D'un Arnés De Parapent De Competició

El present projecte tracta sobre l’estudi i caracterització de l’aerodinàmica i l’estabilitat lateral d’una cadira de competició de parapent, amb l’objectiu de poder explicar el fenomen d’inestabilitat lateral i poder donar criteris de disseny per tal de disminuir-lo. En l’actualitat, les cadires de parapent, quan volen a elevades velocitats, pateixen un fenomen d’inestabilitat lateral que consisteix en l’augment de l’angle entre cadira i ala de parapent, angle de twist. Aquest fenomen pot fer cometre al pilot un error, motiu pel qual interessa conèixer les seves causes i disminuir-lo. Les accions d’aquest projecte es centraran en com afecta la part posterior de la cadira, la cua, al fenomen d’inestabilitat lateral. Així, per aconseguir aquests objectius, primerament s’han caracteritzat els dos moments que actuen sobre la cadira de parapent, el moment aerodinàmic i el moment dels ancoratges. S’ha observat que el primer dels moments és el que fa tendir la cadira a entrar en twist i que, per tant, es pot considerar desestabilitzador. El segon d’ells intenta portar la cadira a la situació de zero twist i, per tant, es pot considerar estabilitzador. En segon lloc, s’han modelat diferents geometries de cua per mitjà del programa SolidWorks i s’han dut a terme un seguit de simulacions paramètriques per mitjà del programa Ansys. Aquestes simulacions han permès veure el comportament aerodinàmic de les diferents geometries sota diversos angles del vent incident. Aquestes han permès concloure que la presència d’una cua millora l’aerodinàmica de la cadira i fa disminuir la tendència a twist per a angles de vent incident grans. Paral·lelament, també s’ha pogut confirmar que la tendència a twist augmenta ràpidament amb la velocitat, ja que les forces aerodinàmiques depenen del quadrat de la velocitat. Finalment, s’ha determinat la dinàmica de moviment quasi-estàtica de les diferents geometries per l’acció conjunta del moment aerodinàmic i moment dels ancoratges. Els resultats d’aquesta anàlisi mostren que les cadires amb una àrea lateral major tenen una tendència a twist menor i que l’angle de twist al qual tendeixen és menor. Els resultats indiquen que no només és important l’augment de l’àrea lateral, sinó que la ubicació d’aquesta àrea lateral també és important; sent l’àrea lateral ubicada a la part posterior de la cua la que més afavoreix la disminució de la tendència a twist. D’aquesta forma, es pot concloure que per tal de reduir la tendència a entrar en twist i el fenomen d’inestabilitat lateral, el disseny de la cadira de parapent ha d’incorporar una cua amb una gran altura a la part posterior de la geometria. Sent la longitud de la cua una variable secundaria que es pot utilitzar per acabar d’ajustar les prestacions de la mateixa

The Use of Virtual Reality in the Study of People's Responses to Violent Incidents

This paper reviews experimental methods for the study of the responses of people to violence in digital media, and in particular considers the issues of internal validity and ecological validity or generalisability of results to events in the real world. Experimental methods typically involve a significant level of abstraction from reality, with participants required to carry out tasks that are far removed from violence in real life, and hence their ecological validity is questionable. On the other hand studies based on field data, while having ecological validity, cannot control multiple confounding variables that may have an impact on observed results, so that their internal validity is questionable. It is argued that immersive virtual reality may provide a unification of these two approaches. Since people tend to respond realistically to situations and events that occur in virtual reality, and since virtual reality simulations can be completely controlled for experimental purposes, studies of responses to violence within virtual reality are likely to have both ecological and internal validity. This depends on a property that we call ‘plausibility’ – including the fidelity of the depicted situation with prior knowledge and expectations. We illustrate this with data from a previously published experiment, a virtual reprise of Stanley Milgram's 1960s obedience experiment, and also with pilot data from a new study being developed that looks at bystander responses to violent incidents

A validation study to trigger nicotine craving in virtual reality

We built a virtual beer garden that contained various smoking cues (both verbal and non-verbal) using a motion capture system to record the realistic smoking behaviour related animations. Our 3-min long VR experience was optimized for Oculus Quest 2 with the hand tracking function enabled. We conducted a pilot study with 13 non-treatment-seeking nicotine-dependent cigarette smokers. The preliminary results indicate that this VR experience led to high levels of presence, and that there is a significant increase of nicotine craving - but only for those who reported a high level of immersion

Virtual reality clinical-experimental tests of compassion treatment techniques to reduce paranoia

Paranoia may build on negative beliefs held both about the self and others. Compassionate imagery may be one way of reducing such negative beliefs, and hence paranoia. Two studies tested this idea, one targeting compassion for the self and one targeting compassion for others. Two-hundred individuals from the general population scoring highly for paranoia were recruited. The studies used a randomised controlled experimental design, with embedded tests for mediation. Study one targeted self-compassion via creation of a compassionate coach (CC) image. Study two targeted compassion for others via loving kindness meditation (LKM). Individuals repeatedly entered neutral virtual reality social environments. Changes in compassion and paranoia were assessed. Compared to controls, the CC group increased in self-compassion (group difference = 2.12, C.I. = 1.57;2.67, p = <0.0001, d = 1.4) and decreased in paranoia (group difference = −1.73, C.I. = −2.48; −0.98, p = <0.0001, d = 0.8). Change in self-compassion explained 57% of change in paranoia. Compared to controls, the LKM group increased their compassion for others (group difference = 3.26, C.I. = 2.72;3.80, p = <0.0001, d = 1.7), and decreased in paranoia (group difference = −1.70, C.I. = −2.50; −0.89, p = <0.0001, d = 0.8). Change in compassion for others explained 67% of change in paranoia. Targeting negative beliefs about the self and others using compassionate imagery causes reductions in paranoia. Tests in clinical populations are indicated

Combining innovative mulches and soil conditioners in mountain afforestation with ash (Fraxinus excelsior L.) in the Pyrenees (NE Spain)

Aim of study: To assess the effectiveness for improving early seedling performance of the individual and combined application of (i) various doses of an innovative soil conditioner including polyacrylamide-free super-absorbent polymers, fertilizers, root precursors and humic acids; and (ii) innovative mulches based on renewable-biodegradable or recycled raw materials. The assessment was carried out in comparison with reference (commercial) soil conditioners and mulches.Area of study: Upper montane afforestation site located at 1,430 m altitude in the southern Pyrenees (NE Spain).Material and methods: We studied the effect of 15 treatments (various combinations of soil conditioners and mulches) on mountain ash (Fraxinus excelsior L.), testing survival, diameter and height growth and water and nutrient status during two growing seasons (2014-2015). We also assessed mulch durability during 2014-2016.Main results: The innovative soil conditioner improved diameter and height seedling growth (92% and 72% respectively) and water and nutrient status. The 40 g/seedling dosage was more cost-effective than the 20 and 80 g/seedling doses. The new formulation performed better in general than the commercial formulation. Mulches led to slight gains compared to control seedlings, and there were no major differences between the mulch models. The combined application of soil conditioners and mulches was not of particular interest.Research highlights: Soil conditioners consisting of synergic mixtures of water super-absorbent polymers, fertilizers, root growth precursors and humic acids can improve early seedling performance in coarse-textured, stony soils in montane conditions. Small mulches may be only of limited interest as long as weed competitiveness is poor.Keywords: ecotechnology; groundcovers; reforestation; seedling performance; restoration; water super-absorbent polymer; weed.Abbreviations used: GSn, growing season number ‘n’; leaf water potential, LWP; water super-absorbent polymers, SAP; soil conditioner with water super-absorbent polymers, SCwSAP; Soil Plant Analysis Development, SPAD

The impact of enhanced projector display on the responses of people to a violent scenario in immersive virtual reality

This paper describes the impact of display resolution and luminance on the responses of participants in a behavioral study that used a projection-based Immersive Virtual Reality System. The scenario was a virtual bar where participants witnessed a violent attack of one person on another due to an argument about support for a soccer club. The major response variable was the number of interventions made by participants. The study was between-groups with 10 participants in two groups pre-upgrade and post-upgrade, both in the same 4-screen Cave-like system. However, the post-upgrade group experienced the scenario with projectors that had a significantly higher level of resolution and luminance than those experienced by the pre-upgrade group. The results show that, other things being equal, the number of both verbal and physical interventions was greater amongst those in the post-upgrade group compared to the pre-upgrade group

Neutral organic radical formation by chemisorption on metal surfaces

Organic radical monolayers (r-MLs) bonded to metal surfaces are potential materials for the development of molecular (spin)electronics. Typically, stable radicals bearing surface anchoring groups are used to generate r-MLs. Following a recent theoretical proposal based on a model system, we report the first experimental realization of a metal surface-induced r-ML, where a rationally chosen closed-shell precursor 3,5-dichloro-4-[bis(2,4,6-trichlorophenyl)methylen]cyclohexa-2,5-dien-1-one (1) transforms into a stable neutral open-shell species () via chemisorption on the Ag(111) surface. X-ray photoelectron spectroscopy reveals that the >C=O group of 1 reacts with the surface, forming a C-O-Ag linkage that induces an electronic rearrangement that transforms 1 to . We further show that surface reactivity is an important factor in this process whereby Au(111) is inert towards 1, whereas the Cu(111) surface leads to dehalogenation reactions. The radical nature of the Ag(111)-bound monolayer was further confirmed by angle-resolved photoelectron spectroscopy and electronic structure calculations, which provide evidence of the emergence of the singly occupied molecular orbital (SOMO) of 1

RECURSOS VIRTUALES PARA LA ENSEÑANZA Y APRENDIZAJE DE TEORÍA DE MÁQUINAS Y MECANISMOS EN INGENIERÍA MECÁNICA

Las universidades españolas están adecuadas al Espacio Europeo de Educación Superior, donde la docencia se cuantifica en créditos ECTS, lo que ha implicado considerar en el trabajo del alumno las horas de tutoría y de trabajo independiente. Ello ha obligado al profesorado a reflexionar sobre cómo adaptar el material docente y enriquecerlo para facilitar el proceso de enseñanza-aprendizaje y el autoestudio del alumno. La utilización de las Tecnologías de la Información y Comunicación, y las posibilidades que ofrecen los softwares de modelación y simulación en diferentes ámbitos de conocimientos, permiten crear y compartir recursos didácticos virtuales que ayudan al docente en la impartición de materias y motivan el aprendizaje. Este artículo expone el procedimiento seguido para la selección, modelación y simulación de los mecanismos objeto de estudio y los recursos virtuales creados (modelos 2D, 3D y vídeos de simulación de su funcionamiento), como medios didácticos de las materias Teoría de Máquinas y Mecanismos y Proyecto II en la Carrera de Ingeniería Mecánica. Los modelos y las simulaciones se han realizado utilizando SolidWorks y su módulo Motion. También se presentan los esquemas de símbolos de los mecanismos, con el objetivo de que los estudiantes fomenten la capacidad de asociación entre los mecanismos reales y los esquemas correspondientes y entiendan mejor su estructura y funcionamiento

RECURSOS VIRTUALES PARA LA ENSEÑANZA Y APRENDIZAJE DE TEORÍA DE MÁQUINAS Y MECANISMOS EN INGENIERÍA MECÁNICA

Las universidades españolas están adecuadas al Espacio Europeo de Educación Superior, donde la docencia se cuantifica en créditos ECTS, lo que ha implicado considerar en el trabajo del alumno las horas de tutoría y de trabajo independiente. Ello ha obligado al profesorado a reflexionar sobre cómo adaptar el material docente y enriquecerlo para facilitar el proceso de enseñanza-aprendizaje y el autoestudio del alumno. La utilización de las Tecnologías de la Información y Comunicación, y las posibilidades que ofrecen los softwares de modelación y simulación en diferentes ámbitos de conocimientos, permiten crear y compartir recursos didácticos virtuales que ayudan al docente en la impartición de materias y motivan el aprendizaje. Este artículo expone el procedimiento seguido para la selección, modelación y simulación de los mecanismos objeto de estudio y los recursos virtuales creados (modelos 2D, 3D y vídeos de simulación de su funcionamiento), como medios didácticos de las materias Teoría de Máquinas y Mecanismos y Proyecto II en la Carrera de Ingeniería Mecánica. Los modelos y las simulaciones se han realizado utilizando SolidWorks y su módulo Motion. También se presentan los esquemas de símbolos de los mecanismos, con el objetivo de que los estudiantes fomenten la capacidad de asociación entre los mecanismos reales y los esquemas correspondientes y entiendan mejor su estructura y funcionamiento