Optical and microstructural properties of MgF2 UV coatings grown by ion beam sputtering process

The optical, mechanical, and microstructural properties of MgF2 single layers grown by ion beam sputtering have been investigated by spectrophotometric measurements, film stress characterization, x-ray photoelectron spectroscopy (XPS), x-ray diffraction, and transmission electron microscopy. The deposition conditions, using fluorine reactive gas or not, have been found to greatly influence the optical absorption and the stress of the films as well as their microstructure. The layers grown with fluorine compensation exhibit a regular columnar microstructure and an UV-optical absorption which can be very low, either as deposited or after thermal annealings at very low temperatures. On the contrary, layers grown without fluorine compensation exhibit a less regular microstructure and a high ultraviolet absorption which is particularly hard to cure. On the basis of calculations, it is shown that F centers are responsible for this absorption, whereas all the films were found to be stoichiometric, in the limit of the XPS sensitivity. On the basis of external data taken from literature, our experimental curves are analyzed, so we propose possible diffusion mechanisms which could explain the behaviors of the coatings.

Tomato response to a high light transmission greenhouse film

Increasing greenhouse light transmission has a positive effect not only in Northern latitudes but in Mediterranean countries as well. A greenhouse, H2, with a tetrafluoroethylene copolymer 60 microns film, (Asahi Glass company, Aflex) characterised by its high light transmission and durability was compared to another greenhouse with a co-extruded film considered as a control, H1. Tomato crop response to the increase in light during winter and summer with high temperature and light was evaluated. Light transmission in H2 remained very high in spite of the observed dust accumulation and the low angle of incidence of the winter solar radiation. Transmissivity was clearly higher for H2 (81 to 83 % throughout the season) than in the control (around 63 %). The rest of the climatic parameters were similar in both greenhouses, either in the winter or in the summer evaluations. In spite of the high solar radiation in H2, the summer temperature could be maintained at the desired levels by using evaporative cooling. Accumulated tomato yield and quality was better in the H2 greenhouse (15 % more for the winter crop and 27% more for the summer crop). Fruit size was bigger in the winter crop. As an overall conclusion, the use of high light transmissive films in Mediterranean areas is very convenient for many vegetable crops. This is valid not only in winter but in summer, provided the greenhouse has good ventilation or evaporative cooling to overcome the increase in sensible heat caused by this increase in light..

Pla de màrqueting de l’hotel Moments de Film

Treball sobre la creació d’un pla de màrqueting d’un hotel temàtic fictici. Aquest sorgeix d’un objectiu secundari fruit d’una motivació personal amb interès cap a la coneixença dels hotels temàtics, que responia a les següents preguntes: Què és un hotel temàtic? Quins tipus d’hotels temàtics podem trobar? Quan sorgeixen els hotels temàtics? El Pla de Màrqueting representa el desenvolupament d’una idea creativa, imaginant que els hotels poden ser molt més que un simple allotjament. Poden esdevenir llocs que poden conduir cap al món de les sensacions i de les experiències úniques

Proposal for the analysis of a video game, a film, and their relationship : Silent Hill as a subject of the horror genre

Aquest treball de recerca fa un estudi comparatiu del videojoc de terror amb el seu homòleg cinematogràfic. L’objectiu és arribar a saber si els dos mitjans de comunicació usen les mateixes tècniques per transmetre les seves històries i per crear suspens. Aquesta investigació és només una part d'un estudi més ampli amb el que es pretén tenir un coneixement més aprofundit de les emocions de la gent i les reaccions que els provoca un videojoc de terror en comparació amb la visualització de l'adaptació cinematogràfica del corresponent videojoc.

Film's frame

A partir de un acto interactivo con la wwww.aeat.es, el usuario envía telemáticamente el modelo 100 en un entorno con tendencia a la incertidumbre y a las dificultades de usabilidad, sin embargo, la investigación pretende demostrar que en dicho acto, el usuario construye una historia narrativa debido a la existencia de una motivación y a la tendencia connatural a la representación narrativa, a pesar que la web no fue intencionalmente construida con propósitos narrativos. El estudio, además, enfoca la interacción como un acto inmersivo y reconoce en la incertidumbre las variables que determinan la continuidad y rumbo del relato. La investigación propone un modelo interpretativo para el análisis y la estructuración del espacio y la historia implícita. Y a nivel exploratorio, se propone la aplicación del Mouse Tracking como técnica científica.

Structural characterization of laser-treated Cr3C2-NiCr coatings

The interconnected porosity of the Cr3C2-NiCr coatings obtained by high-velocity oxy fuel spraying is detrimental in corrosion and wear resistance applications. Laser treatments allow sealing of their surfaces through melting and resolidification of a thin superficial layer. A Nd:YAG laser beam was used to irradiate Cr3C2-NiCr coatings either in the continuous wave mode or at different repetition rates in the pulsed one. Results indicated that high peak and low mean laser irradiances are not good, since samples presented deep grooves and an extensive crack network. At low peak and higher mean laser irradiances the surface was molten, and only a few shallow cracks were observed. The interconnected porosity was completely eliminated in a layer up to 80 m thick, formed by large Cr7C3 grains imbedded in a NiCr matrix.

Radial displacement of a fluid annulus in a rotating Hele¿Shaw cell

The radial displacement of a fluid annulus in a rotating circular Hele-Shaw cell has been investigated experimentally. It has been found that the flow depends sensitively on the wetting conditions at the outer interface. Displacements in a prewet cell are well described by Darcy's law in a wide range of experimental parameters, with little influence of capillary effects. In a dry cell, however, a more careful analysis of the interface motion is required; the interplay between a gradual loss of fluid at the inner interface, and the dependence of capillary forces at the outer interface on interfacial velocity and dynamic contact angle, result in a constant velocity for the interfaces. The experimental results in this case correlate in the form of an empirical scaling relation between the capillary number Ca and a dimensionless group, related to the ratio of centrifugal to capillary forces, which spans about three orders of magnitude in both quantities. Finally, the relative thickness of the coating film left by the inner interface, alpha i, is obtained as a function of Ca.

Three-dimensional aspects of fluid flows in channels. II. Effects of meniscus and thin film regimes on viscous fingers

We perform a three-dimensional study of steady state viscous fingers that develop in linear channels. By means of a three-dimensional lattice-Boltzmann scheme that mimics the full macroscopic equations of motion of the fluid momentum and order parameter, we study the effect of the thickness of the channel in two cases. First, for total displacement of the fluids in the channel thickness direction, we find that the steady state finger is effectively two-dimensional and that previous two-dimensional results can be recovered by taking into account the effect of a curved meniscus across the channel thickness as a contribution to surface stresses. Second, when a thin film develops in the channel thickness direction, the finger narrows with increasing channel aspect ratio in agreement with experimental results. The effect of the thin film renders the problem three-dimensional and results deviate from the two-dimensional prediction.

Three-dimensional aspects of fluid flows in channels. I. Meniscus and thin film regimes

We study the forced displacement of a fluid-fluid interface in a three-dimensional channel formed by two parallel solid plates. Using a lattice-Boltzmann method, we study situations in which a slip velocity arises from diffusion effects near the contact line. The difference between the slip and channel velocities determines whether the interface advances as a meniscus or a thin film of fluid is left adhered to the plates. We find that this effect is controlled by the capillary and Péclet numbers. We estimate the crossover from a meniscus to a thin film and find good agreement with numerical results. The penetration regime is examined in the steady state. We find that the occupation fraction of the advancing finger relative to the channel thickness is controlled by the capillary number and the viscosity contrast between the fluids. For high viscosity contrast, lattice-Boltzmann results agree with previous results. For zero viscosity contrast, we observe remarkably narrow fingers. The shape of the finger is found to be universal.

Hedwig and The Angry Inch: Plato at the Sundance Film Festival

The aim of this article is to show how an ancient myth, that of the three genres, also known as the myth of the androgynous by Aristophanes in Plato¿s Symposium, becomes for John Cameron Mitchell the suitable image in order to explain the peculiar personality of a man, Hedwig, who by means of a surgical operation becomes in his turn an imperfect androgynous but symbolises the need of a sole mankind or the unity of different worlds, just as he belonged to both Berlins divided by an already fallen wall, which permitted their inhabitants to recover their lost unity and identity.

Low temperature amorphous and nanocrystalline silicon thin film transistors deposited by Hot-Wire CVD on glass substrate

Amorphous and nanocrystalline silicon films obtained by Hot-Wire Chemical Vapor Deposition have been incorporated as active layers in n-type coplanar top gate thin film transistors deposited on glass substrates covered with SiO 2. Amorphous silicon devices exhibited mobility values of 1.3 cm 2 V - 1 s - 1, which are very high taking into account the amorphous nature of the material. Nanocrystalline transistors presented mobility values as high as 11.5 cm 2 V - 1 s - 1 and resulted in low threshold voltage shift (∼ 0.5 V).

Hydroxyapatite coatings grown by pulsed laser deposition with a beam of 355 nm wavelength

Calcium phosphate coatings, obtained at different deposition rates by pulsed laser deposition with a Nd:YAG laser beam of 355-nm wavelength, were studied. The deposition rate was changed from 0.043 to 1.16 /shot by modification of only the ablated area, maintaining the local fluence constant to perform the ablation process in similar local conditions. Characterization of the coatings was performed by scanning electron microscopy, x-ray diffractometry, and infrared, micro-Raman, and x-ray photoelectron spectroscopy. The coatings showed a compact surface morphology formed by glassy gains with some droplets on them. Only hydroxyapatite (HA) and alpha-tricalcium phosphate (alpha-TCP) peaks were found in the x-ray diffractograms. The relative content of alpha TCP diminished with decreasing deposition rates, and only HA peaks were found for the lowest rate. The origin of alpha TCP is discussed.

Structural characterization of laser-treated Cr3C2-NiCr coatings

The interconnected porosity of the Cr3C2-NiCr coatings obtained by high-velocity oxy fuel spraying is detrimental in corrosion and wear resistance applications. Laser treatments allow sealing of their surfaces through melting and resolidification of a thin superficial layer. A Nd:YAG laser beam was used to irradiate Cr3C2-NiCr coatings either in the continuous wave mode or at different repetition rates in the pulsed one. Results indicated that high peak and low mean laser irradiances are not good, since samples presented deep grooves and an extensive crack network. At low peak and higher mean laser irradiances the surface was molten, and only a few shallow cracks were observed. The interconnected porosity was completely eliminated in a layer up to 80 m thick, formed by large Cr7C3 grains imbedded in a NiCr matrix.

Film-free laser forward printing of transparent and weakly absorbing liquids

A laser-based technique for printing transparent and weakly absorbing liquids is developed. Its principle of operation relies in the tight focusing of short laser pulses inside the liquid and close to its free surface, in such a way that the laser radiation is absorbed in a tiny volume around the beam waist, with practically no absorption in any other location along the beam path. If the absorbed energy overcomes the optical breakdown threshold, a cavitation bubble is generated, and its expansion results in the propulsion of a small fraction of liquid which can be collected on a substrate, leading to the printing of a microdroplet for each laser pulse. The technique does not require the preparation of the liquid in thin film form, and its forward mode of operation imposes no restriction concerning the optical properties of the substrate. These characteristics make it well suited for printing a wide variety of materials of interest in diverse applications. We demonstrate that the film-free laser forward printing technique is capable of printing microdroplets with good resolution, reproducibility and control, and analyze the influence of the main process parameter, laser pulse energy. The mechanisms of liquid printing are also investigated: time-resolved imaging provides a clear picture of the dynamics of liquid transfer which allows understanding the main features observed in the printed droplets.