Asymmetric amplification in amino acid sublimation involving racemic compound to conglomerate conversion

A straightforward unprecedented sublimation protocol that reveals both conversion of a racemic compound into a racemic conglomerate and subsequent enantioenrichment has been developed for the proteinogenic amino acid valine. The phenomenon has been observed in closed and open systems, providing insight into asymmetric amplification mechanisms under presumably prebiotic conditions

Time derivatives in air temperature and enthalpy as non-invasive welfare indicators during long distance animal transport in Spain and Portugal.

High temperatures and relative humidity can compromise animal welfare on the farm level, but less is known about those changes during long distance transport of domestic animals to slaughter. Although upper temperature limits have been established to transport pigs in Europe, few indices include relative or absolute humidity maxima or mention appropriate enthalpy ranges.

Design of a solar incubator. Part 1: Monitoring temperature and enthalpy gradients under commercial production

The real increase in energy prices and the intention of reducing pollutant emissions in developed countries makes interesting to use solar energy in all the processes where its application is possible. As it is demonstrated in countries sited at latitudes with optimal conditions of solar radiation and temperature, it is possible to use solar energy as heat source for small-scale hatchery [1,2], but beyond, making a design for proper installation; it is possible to use solar energy as main or support energy source in medium and large size incubators . Monitoring of a normal actual process using temperature and relative humidity sensors is necessary to know the actual operating conditions that the solar heating system must be designed and sized for. Moreover, the identification and analysis of temperature and enthalpy gradients inside the incubator is of major importance.

The Phase Space as a New Representation of the Dynamical Behaviour of Temperature and Enthalpy in a Reefer monitored with a Multidistributed Sensors Network

The study of temperature gradients in cold stores and containers is a critical issue in the food industry for the quality assurance of products during transport, as well as forminimizing losses. The objective of this work is to develop a new methodology of data analysis based on phase space graphs of temperature and enthalpy, collected by means of multidistributed, low cost and autonomous wireless sensors and loggers. A transoceanic refrigerated transport of lemons in a reefer container ship from Montevideo (Uruguay) to Cartagena (Spain) was monitored with a network of 39 semi-passive TurboTag RFID loggers and 13 i-button loggers. Transport included intermodal transit from transoceanic to short shipping vessels and a truck trip. Data analysis is carried out using qualitative phase diagrams computed on the basis of Takens?Ruelle reconstruction of attractors. Fruit stress is quantified in terms of the phase diagram area which characterizes the cyclic behaviour of temperature. Areas within the enthalpy phase diagram computed for the short sea shipping transport were 5 times higher than those computed for the long sea shipping, with coefficients of variation above 100% for both periods. This new methodology for data analysis highlights the significant heterogeneity of thermohygrometric conditions at different locations in the container.

Laser ablation modelling of aluminium, silver and crystalline silicon for applications in photovoltaic technologies

Laser material processing is being extensively used in photovoltaic applications for both the fabrication of thin film modules and the enhancement of the crystalline silicon solar cells. The two temperature model for thermal diffusion was numerically solved in this paper. Laser pulses of 1064, 532 or 248 nm with duration of 35, 26 or 10 ns were considered as the thermal source leading to the material ablation. Considering high irradiance levels (108–109 W cm−2), a total absorption of the energy during the ablation process was assumed in the model. The materials analysed in the simulation were aluminium (Al) and silver (Ag), which are commonly used as metallic electrodes in photovoltaic devices. Moreover, thermal diffusion was also simulated for crystalline silicon (c-Si). A similar trend of temperature as a function of depth and time was found for both metals and c-Si regardless of the employed wavelength. For each material, the ablation depth dependence on laser pulse parameters was determined by means of an ablation criterion. Thus, after the laser pulse, the maximum depth for which the total energy stored in the material is equal to the vaporisation enthalpy was considered as the ablation depth. For all cases, the ablation depth increased with the laser pulse fluence and did not exhibit a clear correlation with the radiation wavelength. Finally, the experimental validation of the simulation results was carried out and the ability of the model with the initial hypothesis of total energy absorption to closely fit experimental results was confirmed.

Effects of high hydrostatic pressure on rheological and termal properties of chickpea Cicer arietinum L. flour slurry and heat-induced paste.

Thermorheological changes in high hydrostatic pressure (HHP)-treated chickpea flour (CF) slurries were studied as a function of pressure level (0.1, 150, 300, 400, and 600 MPa) and slurry concentration (1:5, 1:4, 1:3, and 1:2 flour-to-water ratios). HHP-treated slurries were subsequently analyzed for changes in properties produced by heating, under both isothermal and non-isothermal processes. Elasticity (G′) of pressurized slurry increased with pressure applied and concentration. Conversely, heat-induced CF paste gradually transformed from solid-like behavior to liquid-like behavior as a function of moisture content and pressure level. The G′ and enthalpy of the CF paste decreased with increasing pressure level in proportion with the extent of HHP-induced starch gelatinization. At 25 °C and 15 min, HHP treatment at 450 and 600 MPa was sufficient to complete gelatinization of CF slurry at the lowest concentration (1:5), while more concentrated slurries would require higher pressures and temperature during treatment or longer holding times. Industrial relevance Demand for chickpea gel has increased considerably in the health and food industries because of its many beneficial effects. However, its use is affected by its very difficult handling. Judicious application of high hydrostatic pressure (HHP) at appropriate levels, adopted as a pre-processing instrument in combination with heating processes, is presented as an innovative technology to produce a remarkable decrease in thermo-hardening of heat-induced chickpea flour paste, permitting the development of new chickpea-based products with desirable handling properties and sensory attributes.

Aplicación de energía geotérmica de muy baja entalpia para la climatización de un edificio de oficinas en Alcorcón, Madrid

El presente Proyecto tiene como propósito el estudio de la viabilidad de la implantación de energía geotérmica de muy baja entalpia para la climatización de un edificio empresarial en Madrid. Para ello se emplearon cálculos teóricos y simulaciones realizadas mediante programas informaticos especializados con el fin de estimar los parámetros técnicos necesarios para su viabilidad. Se estimo el suministro de la potencia necesaria a través de tres bombas de calor tipo agua-agua que sustituyen a las bombas de calor aire-agua individuales anteriormente instaladas. El intercambio de calor se realiza a través de sondas geotérmicas U-Simple. Se dimensionaron los colectores, bombas de circulación, deposito de inercia y vaso de expansión necesarios para funcionamiento del sistema. El estudio económico determino la necesidad de una alta inversión inicial, con una rentabilidad a medio plazo. Además de los beneficios económicos se realizo un estudio de las emisiones de gases de efecto invernadero demostrando la reducción de los mismos, lo que refleja que además de ser una tecnología económicamente viable es una energía limpia. ABSTRACT The objective of the present project is to evaluate the viability of the imposition of a low-enthalpy geothermal energy system for air conditioning in a business building in Madrid. In this study, both theoretical calculations and numerical simulations in specialized programs were used in order to estimate the technical parameters needed for its viability. We estimated the necessary power supply, which is delivered by three heat water-water pumps that substitute the individual heat air-water pumps previously installed. The heat exchange is achieved through geothermal vertical simple-U probes. Also in this work we have measured the collectors, flow pumps, inertia deposit and the water expansion vessel needed for the proper operation of the system. The economic study determined the need of a high initial investment with mid-term profit. In addition to the economic benefits, the greenhouse gases emissions were evaluated, finding that the geothermal energy system implies a reduction of these emissions. This reflects the fact that, in addition to being economically viable, the geothermal energy is considered a clean energy.

La cabaña moderna. Microrrelatos de arquitecturas en busca de sentido

Desde la revolución ilustrada e industrial de finales del s. XVIII se ha venido desarrollando, con fuerza inigualada a lo largo de la historia, algo que es consustancial al hombre y que le ha permitido constituirse como tal frente al resto de animales: la técnica. Como sentencia Ortega, no hay hombre sin técnica. Pero, al mismo tiempo, va quedando cada vez más claro -como también nos señala Ortega- que el sentido y la causa de la técnica están fuera de ella, y que la técnica no es en rigor lo primero, sino que su finalidad le ha de ser prefijada por un deseo original pre-técnico. Si esto no fuera así el hombre perdería su propio sentido, pues el hombre es puro afán, un ente cuyo ser consiste no en lo que ya es, sino en la que aún no es. Sin embargo, el progresivo desencantamiento del mundo como consecuencia del desarrollo de la sociedad industrial vino a sustituir los viejos mitos por una interpretación racional y abstracta que renunciaba a cualquier búsqueda de sentido que trascendiese los hechos brutos. De este modo, la perdida de sentido del hombre frente a la técnica desarrollada por él mismo le dejaba desnortado y convertido en un sujeto pasivo en manos de un malentendido progreso. Frente a esta pérdida de sentido detectada ya a principios del siglo XX y denunciada con más fuerza a partir de la Segunda Guerra Mundial, el postmodernismo del último tramo del pasado siglo pudo no sólo oficializar su desaparición, sino consignar su deslegitimación. Ante a esto, sostenemos la necesaria existencia de sentido en cualquier arquitectura que se desarrolle plenamente y, especialmente, en la arquitectura de la modernidad -y aún de la modernidad tardía o postmodernidad- muchas de las veces no explicitado como tal frente al sobredimensionamiento técnico que ha venido marcando la pauta desde la revolución industrial. Al mismo tiempo, ya no se puede hablar de un único sentido, universalizable, sino de una pluralidad de sentidos que definirán distintas arquitecturas. Partiendo de la petitio principii de que el tema capital de la arquitectura en la modernidad ha sido la vivienda, el objeto arquitectónico que reúne las mejores características para desarrollar esta búsqueda de sentido lo hemos encontrado en la cabaña moderna, donde se cumple el aforismo corbusierano que señala que “quand l’économie est au maximum, l’intensité est au maximum”. Al mismo tiempo “al representar la plenitud a través de su misma negación”, la cabaña moderna se puede entender como una sublimación de la arquitectura a través de pequeños objetos donde han quedado destiladas las distintas esencias de la modernidad. Mediante el análisis de seis pequeñas construcciones situadas en archipiélagos arquitectónicos radicalmente distantes –el campamento de Ocatillo (F. Ll. Wright, 1929); la Caja (R. Erskine, 1942); el Cabanon (Le Corbusier, 1952); la casa cúpula en Carbondale (R. B. Fuller, 1960); el refugio en Oropesa (F. J. Sáenz de Oíza, c.1967-1977) y el pabellón de invitados en Kempsey (G. Murcutt, 1992)- la aparente aporía que supone la cabaña moderna, frente a la más lógica, en principio, cabaña primitiva, cobra sentido. Efectiva mente, el referente mítico de la cabaña primitiva, tal y como fue enunciado por Laugier, se correspondía con el estadio más primitivo de la modernidad, con sus orígenes, precisamente porque la crítica que se hacía en ella de la arquitectura se basaba en criterios exclusivamente técnicos que remitían a los orígenes constructivos de la arquitectura como fórmula para salir del entramado retórico en el que ésta se encontraba perdida. La cabaña moderna trasciende, sin embargo, aquella primitiva fase de la modernidad, de la que la cabaña de Laugier es paradigma, en la medida en que la crítica que se realiza ahora es doble, pues a la crítica de carácter técnico que encontramos en cada una de las cabañas se le añade una crítica de sentido que no se encuentra supeditada, en ninguno de los casos, a la componente técnica, tal y como sin embargo sucedía con Laugier, donde la pretendida regeneración moral de la arquitectura era consecuencia directa de su depuración técnica. En la cabaña moderna, al contrario, encontramos una pluralidad de sentidos que orientan y fuerzan el desarrollo de la techné en direcciones que llegan a ser radicalmente diferentes, construyendo unos relatos que habrán de ser, por tanto, necesariamente parciales, pero de los que la arquitectura, en cualquier caso no podrá prescindir si es que quiere seguir siendo fiel a sí misma, tal y como, efectivamente, lo comprendieron Wright, Erskine, Le Corbusier, Fuller, Sáenz de Oíza y Murcutt, cuando se esforzaron por que estas pequeñas arquitecturas que hemos visitado, tan sólo unas cabañas, fueran unas cabañas con sentido, unas cabañas modernas. ABSTRACT Since the illustrated and industrial revolution of the XVIII century it has been developing, with unequally strength through history, something that is inherent to man and that has allowed him to become himself against the rest of animals: technique. As Ortega says, there is no man without technique. But, at the same time, it is becoming increasingly clear –as Ortega also says- that the sense and the cause of the technique are beyond technique itself, and that technique is not actually the first thing, but that its purpose must be predefined by a pre-technique original desire. If it were not like this, man would lose his own sense, because man is pure desire, an entity whose being is not what already is, but what still doesn’t is. However, the progressive disenchantment of the world as the result of the development of the industrial society came to change the old myths by a rational and abstract interpretation that renounced to any search of meaning that transcended the brute facts. Thereby, the loss of sense of man against the technique developed by man himself let him aimless and converted in a passive object in the hands of a misunderstood progress. Against this loss of sense already detected at the beginning of the XX century and denounced in a stronger way since the Second World War, the postmodernism of the late decades of the last century could not only formalize its disappearance, but also consign its delegitimization. On the contrary, we maintain the necessary existence of sense in any architecture that is fully developed and, specially, in the modern architecture –and even in the late Modernism or Postmodernism- many times not made explicit as such against the technique oversizing that has been setting the pattern since the industrial revolution. At the same time, we can not talk about an only and universal sense, but about a plurality of senses that will define different architectures. On the basis of the petitio principii that dwelling has been the capital issue of modern architecture, the architectonic object that possesses the best features for developing this search of sense has been found in the modern hut, where is fulfil the Corbusieran aphorism that says that “quand l’économie est au maximum, l’intensité est au maximum”. At the same time, “representing plenitude through its own negation” the modern hut can be understood as a sublimation of architecture through small objects where the different essences of modernity have been distilled. Through the analysis of six small buildings located in radically distant architectonic archipelagos –the Ocatillo dessert camp (F. Ll. Wright, 1929); the Box (R. Erskine, 1942); the Cabanon (Le Corbusier, 1952); the dome-home in Carbondale (R. B. Fuller, 1960); the retreat in Oropesa (F. J. Sáenz de Oíza, c. 1967-1977) and the guest house in Kimpsey (G. Murcutt, 1992)- the apparent aporia that represents the modern hut, against the, initially, more logical primitive hut, makes sense. Indeed, the mythical reference of the primitive hut, as it was enunciated by Laugier, belonged to the most primitive state of modernity, with its origins, precisely because the criticism of the architecture that was made there was based in exclusively technique criteria, referring to the constructive origins of architecture as the formula to get out of the rhetoric labyrinth in which architecture was lost at the moment. However, the modern hut transcends that primitive phase of modernity, of which Laugier’s hut is paradigm, since the criticism that is made is double, because to the criticism on the technique that we find in every hut we must add a criticism on the sense that is never subordinated to the technique component, as it was the case in Laugier, where the intended architectonic moral regeneration was a direct consequence of its technical depuration. In the modern hut, on the contrary, we find a plurality of senses that guides and drives the development of techné in radically different directions, building narratives that must be, then, necessarilly partial, but of which architecture could never leave aside if it still wants to be faithful to itself, as Wright, Erskine, Le Corbusier, Fuller, Sáenz de Oíza and Murcutt seemed to understand when they tried hardly to make these small architectures that we have visited, these huts, huts full of sense, modern huts.

Thermomechanical relaxation and different water states in cottonseed protein derived bioplastics

Thermomechanical relaxation events and different water states in cottonseed protein bioplastics are presented whilst investigating the effects of aldehyde cross-linking agents. Thermomechanical relaxation of cottonseed protein bioplastics associated with protein denaturation, moisture absorption and broad glass transitions (Tg) were observed from DSC and DMA measurements. It was shown that variation of the aldehyde influences the storage modulus at very low temperature (below Tg). From measurements of the water fusion point, enthalpy, vaporisation, and weight loss, three water states in the water-absorbed bioplastics are suggested; namely strongly-bound-to-polymer, weakly-bound-to-polymer and bulk-like water. The water content and unreacted cross-linking agents are influential factors in controlling formation of the different water states, whilst the selection of different aldehydes was found to be negligible. These results could be valuable for adjusting the thermomechanical relaxations of protein based bioplastics, and tailoring their properties in wet environments.

Multiscale modeling of the plastic behaviour in single crystal tungsten: from atomistic to crystal plasticity simulations

En una planta de fusión, los materiales en contacto con el plasma así como los materiales de primera pared experimentan condiciones particularmente hostiles al estar expuestos a altos flujos de partículas, neutrones y grandes cargas térmicas. Como consecuencia de estas diferentes y complejas condiciones de trabajo, el estudio, desarrollo y diseño de estos materiales es uno de los más importantes retos que ha surgido en los últimos años para la comunidad científica en el campo de los materiales y la energía. Debido a su baja tasa de erosión, alta resistencia al sputtering, alta conductividad térmica, muy alto punto de fusión y baja retención de tritio, el tungsteno (wolframio) es un importante candidato como material de primera pared y como posible material estructural avanzado en fusión por confinamiento magnético e inercial. Sin embargo, el tiempo de vida del tungsteno viene controlado por diversos factores como son su respuesta termo-mecánica en la superficie, la posibilidad de fusión y el fallo por acumulación de helio. Es por ello que el tiempo de vida limitado por la respuesta mecánica del tungsteno (W), y en particular su fragilidad, sean dos importantes aspectos que tienes que ser investigados. El comportamiento plástico en materiales refractarios con estructura cristalina cúbica centrada en las caras (bcc) como el tungsteno está gobernado por las dislocaciones de tipo tornillo a escala atómica y por conjuntos e interacciones de dislocaciones a escalas más grandes. El modelado de este complejo comportamiento requiere la aplicación de métodos capaces de resolver de forma rigurosa cada una de las escalas. El trabajo que se presenta en esta tesis propone un modelado multiescala que es capaz de dar respuestas ingenieriles a las solicitudes técnicas del tungsteno, y que a su vez está apoyado por la rigurosa física subyacente a extensas simulaciones atomísticas. En primer lugar, las propiedades estáticas y dinámicas de las dislocaciones de tipo tornillo en cinco potenciales interatómicos de tungsteno son comparadas, determinando cuáles de ellos garantizan una mayor fidelidad física y eficiencia computacional. Las grandes tasas de deformación asociadas a las técnicas de dinámica molecular hacen que las funciones de movilidad de las dislocaciones obtenidas no puedan ser utilizadas en los siguientes pasos del modelado multiescala. En este trabajo, proponemos dos métodos alternativos para obtener las funciones de movilidad de las dislocaciones: un modelo Monte Cario cinético y expresiones analíticas. El conjunto de parámetros necesarios para formular el modelo de Monte Cario cinético y la ley de movilidad analítica son calculados atomísticamente. Estos parámetros incluyen, pero no se limitan a: la determinación de las entalpias y energías de formación de las parejas de escalones que forman las dislocaciones, la parametrización de los efectos de no Schmid característicos en materiales bcc,etc. Conociendo la ley de movilidad de las dislocaciones en función del esfuerzo aplicado y la temperatura, se introduce esta relación como ecuación de flujo dentro de un modelo de plasticidad cristalina. La predicción del modelo sobre la dependencia del límite de fluencia con la temperatura es validada experimentalmente con ensayos uniaxiales en tungsteno monocristalino. A continuación, se calcula el límite de fluencia al aplicar ensayos uniaxiales de tensión para un conjunto de orientaciones cristalográticas dentro del triángulo estándar variando la tasa de deformación y la temperatura de los ensayos. Finalmente, y con el objetivo de ser capaces de predecir una respuesta más dúctil del tungsteno para una variedad de estados de carga, se realizan ensayos biaxiales de tensión sobre algunas de las orientaciones cristalográficas ya estudiadas en función de la temperatura.-------------------------------------------------------------------------ABSTRACT ----------------------------------------------------------Tungsten and tungsten alloys are being considered as leading candidates for structural and functional materials in future fusion energy devices. The most attractive properties of tungsten for the design of magnetic and inertial fusion energy reactors are its high melting point, high thermal conductivity, low sputtering yield and low longterm disposal radioactive footprint. However, tungsten also presents a very low fracture toughness, mostly associated with inter-granular failure and bulk plasticity, that limits its applications. As a result of these various and complex conditions of work, the study, development and design of these materials is one of the most important challenges that have emerged in recent years to the scientific community in the field of materials for energy applications. The plastic behavior of body-centered cubic (bcc) refractory metals like tungsten is governed by the kink-pair mediated thermally activated motion of h¿ (\1 11)i screw dislocations on the atomistic scale and by ensembles and interactions of dislocations at larger scales. Modeling this complex behavior requires the application of methods capable of resolving rigorously each relevant scale. The work presented in this thesis proposes a multiscale model approach that gives engineering-level responses to the technical specifications required for the use of tungsten in fusion energy reactors, and it is also supported by the rigorous underlying physics of extensive atomistic simulations. First, the static and dynamic properties of screw dislocations in five interatomic potentials for tungsten are compared, determining which of these ensure greater physical fidelity and computational efficiency. The large strain rates associated with molecular dynamics techniques make the dislocation mobility functions obtained not suitable to be used in the next steps of the multiscale model. Therefore, it is necessary to employ mobility laws obtained from a different method. In this work, we suggest two alternative methods to get the dislocation mobility functions: a kinetic Monte Carlo model and analytical expressions. The set of parameters needed to formulate the kinetic Monte Carlo model and the analytical mobility law are calculated atomistically. These parameters include, but are not limited to: enthalpy and energy barriers of kink-pairs as a function of the stress, width of the kink-pairs, non-Schmid effects ( both twinning-antitwinning asymmetry and non-glide stresses), etc. The function relating dislocation velocity with applied stress and temperature is used as the main source of constitutive information into a dislocation-based crystal plasticity framework. We validate the dependence of the yield strength with the temperature predicted by the model against existing experimental data of tensile tests in singlecrystal tungsten, with excellent agreement between the simulations and the measured data. We then extend the model to a number of crystallographic orientations uniformly distributed in the standard triangle and study the effects of temperature and strain rate. Finally, we perform biaxial tensile tests and provide the yield surface as a function of the temperature for some of the crystallographic orientations explored in the uniaxial tensile tests.