Ab-initio based analytical evaluation of entropy in magnetocaloric materials with first order phase transitions

We combine spin polarised density functional theory and thermodynamic mean field theory to describe the phase transitions of antiperovskite manganese nitrides. We find that the inclusion of the localized spin contribution to the entropy, evaluated through mean field theory, lowers the transition temperatures. Furthermore, we show that the electronic entropy leads to first order phase transitions in agreement with experiments whereas the localized spin contribution adds second order character to the transition. We compare our predictions to available experimental data to assess the validity of the assumptions underpinning our multilevel modelling.Comment: PDFLaTeX, 10 pages, 4 figures, 2 tables, accepted for publication in Physics Procedia as ICM 2015 Conference Proceedin

Thermodynamic transport theory of spin waves in ferromagnetic insulators

We use the Boltzmann transport theory in the relaxation time approximation to describe the thermal transport of spin waves in a ferromagnet. By treating spin waves as magnon excitations we are able to compute analytically and numerically the coefficients of the constitutive thermo-magnetic transport equations. As a main result, we find that the absolute thermo-magnetic power coefficient $\epsilon_M$, relating the gradient of the potential of the magnetization current and the gradient of the temperature, in the limit of low temperature and low field, is a constant $\epsilon_M = -0.6419 \, k_B/\mu_B$. The theory correctly describes the low-temperature and magnetic-field dependencies of spin Seebeck experiments. Furthermore, the theory predicts that in the limit of very low temperatures the spin Peltier coefficient $\Pi_M$, relating the heat and the magnetization currents, tends to a finite value which depends on the amplitude of the magnetic field. This indicates the possibility to exploit the spin Peltier effect as an efficient cooling mechanism in cryogenics.Comment: (v1) PDFLaTeX, 10 pages, 5 figures, 1 table, submitted to Phys. Rev. B; (v2) PDFLaTeX, 12 pages, 5 figures, 1 table; Secs. I, III, IV highly improved, old-Sec. VI splitted into two new Secs. VI-VII, references added, typos corrected, revised version re-submitted to Phys. Rev. B; (v3) PDFLaTeX, 12 pages, 5 figures, 1 table; Refs. [3], [27], [36] updated, final version published in Phys. Rev.

Kinetics of heat flux avalanches at the first order transition in La(Fe-Mn-Si)13_{13}-H1.65_{1.65} compounds

We study heat flux avalanches occurring at the first order transition in La(Fe-Mn-Si)$_{13}$-H$_{1.65}$ magnetocaloric material. As the transition is associated to the phase boundaries motion that gives rise to the latent heat, we develop a non equilibrium thermodynamic model. By comparing the model with experimental calorimetry data available for Mn=0.18, we find the values of the intrinsic kinetic parameter $R_L$, expressing the damping for the moving boundary interface, at different magnetic fields. We conclude that by increasing field, thus approaching the critical point, the avalanches increase in number and their kinetics is slowed down.Comment: PDFLaTeX, 5 pages, 2 figures, 1 table, accepted for publication in Journal of Physics: Conference Series as Conference Proceeding of JEMS 2016 (8th Joint European Magnetic Symposia

Building relationships with the local community : approaches to community engagement at Australian folk festivals

University of Technology, Sydney. Faculty of Business.This thesis focuses on the social dimension of event impacts, and seeks to provide insights into those approaches employed by Australian Folk Festivals to engage with their local communities from the point of view of event organisers. Over the past decade there has been an increased awareness of the impacts, both positive and negative, that events have on their host communities, and a recognition that community support can play an important role in the success and longevity of the event itself. While event-hosting communities are acknowledged as important stakeholders for festival organisations, little effort has been made to identify the spectrum of practices purposefully employed to seek their engagement and manage their relationship. This exploratory study has sought to go some way towards the understanding of a ‘continuum’ of community engagement within events and in so doing, provides event managers with a deeper appreciation of the approaches to host community engagement available to them during the planning and delivery phases of their events. A qualitative exploratory research approach was employed, with the intent of providing insights into the issue of concern to this study, which was reflected in the enquiry’s research aim: Identify the spectrum of approaches and practices used by the organisers of folk festivals to engage with their local communities with a view to building relationships leading to both event longevity and positive community outcomes. An extensive literature review was conducted, the results of which were employed to frame a series of in-depth interview questions, which were then posed to a number of festivals (20) listed, amongst others, on the Folk Alliance Australia calendar of events. The practices identified from the analysis of this data were then placed into one of three engagement categories - transactional, transitional or transformational. The practices within these groupings were then explored in terms of their intent. Those factors that served to facilitate or hinder them were also noted, along with the stakeholder groups linked to them. The enquiry found that the practices used by event organisers seeking to build relationships with their communities are predominantly of transactional and transitional nature, with events acknowledging the importance of engaging with their communities yet retaining control of the process. Only a few examples were found of transformational strategies. However, while the study provided an understanding of the strategies currently in use, it also highlighted that the community engagement continuum only partially reflects the diversity of experiences of folk festival organisations in this area. This suggests that the engagement process in the context of Australian folk festivals is a complex one, that could benefit from a strategic focus. The significance of this study lies in its capacity to provide event organisers, both in the folk festival area and in the broader public events field, with a deeper appreciation of the range of potential practices available to them when seeking to engage their host communities, along with those factors that might impact such efforts. This appreciation in turn, should serve to ‘sharpen’ the strategic focus of such events in the community engagement area, and assist them in articulating their engagement efforts when seeking government support through public grants. In conclusion, the study identified opportunities for further research, specifically: the investigation of the insights emerging from this study in other public event settings; and the exploration of stakeholder perspectives on the effectiveness of the various approaches to community engagement identified here, along with their desired outcomes

Studio della sostanza organica in suoli mediterranei mediante tecniche di Risonanza Magnetica Nucleare allo stato solido

In questo lavoro sono state utilizzate tecniche NMR a stato solido per studiare la SOM di tre suoli mediterranei. I tre suoli scelti sono abbastanza simili per tessitura e per tipo di vegetazione presente, ma effettuando un'analisi dettagliata con la 13C NMR a stato solido sono state messe in luce differenze nella strutturazione della SOM altrimenti sconosciute

Multivariate data assimilation in snow modelling at Alpine sites

The knowledge of snowpack dynamics is of critical importance to several real-time applications such as agricultural production, water resource management, flood prevention, hydropower generation, especially in mountain basins. Snowpack state can be estimated by models or from observations, even though both these sources of information are affected by several errors

Atrocidad, vínculos y vindicta pública. naturaleza jurídica y dispositivos procesales. rosario (argentina), 1850-1900

Este trabalho estuda de que maneira a atrocidade, ou seja, a qualificação penal própria do Antigo Regime continuou operando judicialmente durante o século XIX. Observa-se isto a partir de demandas que foram apresentadas no Tribunal Comum de Justiça da 2ª Circunscrição do Estado de Santa Fé, com sede na cidade de Rosário, durante a segunda metade do século XIX, por homicídios que têm o agravamento pelo fato de existir um vínculo entre o morto e o assassino, e também, por suicídios. A complexidade legal do período que se está analisando e a incipiente jurisprudência mostram sentidos “jurídico-conceptuais” do antigo Código, perante as decisões judiciais que se ajustam aos novos modelos legais. Não só a falta de provas, mas, também, algumas dificuldades do procedimento determinaram a diminuição das penas nos casos supramencionados, que continuavam sendo qualificados como atrozesThis paper studies how the atrocity, that is to say, the criminal qualification of the Old Regime continued operating in court during the 19th century. This can be observed from demands that were presented at the Common Court of Justice of the 2nd Constituency of the State of Santa Fe, based in the city of Rosario, during the second half of the 19th century, by homicides that have the aggravation by the fact that there is a link between the dead and the killer, and also, for suicides. The legal complexity of the period that is being analyzed and the incipient jurisprudence show “conceptual and legal” senses of the old Code, in face of the judicial decisions that fit the new legal models. Not only the lack of evidence, but also, some difficulties with the procedure, determined the decrease of penalties in the above mentioned cases, which continued being qualified as atrociousEste trabajo estudia de qué manera la atrocidad, calificación penal propia del Antiguo Régimen continuó operando judicialmente durante el siglo XIX. Esto se observa a partir de causas judicializadas ante el Juzgado de Primera Instancia de la 2a Circunscripción de la provincia de Santa Fe, con sede en la ciudad de Rosario, durante la segunda mitad del siglo XIX por homicidios agravados por el vínculo y suicidios. La complejidad legal del periodo bajo análisis y la incipiente jurisprudencia muestran sentidos “jurídico-conceptuales” de tipo antiguo frente a decisiones judiciales ajustadas a los nuevos referentes legales. La precariedad de las pruebas y algunas dificultades procedimentales determinaban la atenuación de las penas en estos homicidios/suicidios que seguían siendo adjetivados bajo los rótulos de atrocesFil: Piazzi, Carolina Andrea. Universidad Nacional de Rosario. Facultad de Humanidades y Artes. Escuela de Historia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Hábitat coralígeno: patrones de distribución vertical de conjuntos de macroalgas

The present study investigates patterns of distribution of macroalgal coralligenous assemblages in relation to depth and evaluates the role of different environmental conditions on these patterns. Two depths (30 and 40 m) were investigated off small islands and off continental coasts in order to select two different environmental conditions. Results showed differences between depths in the structure of assemblages around islands, while along the continental coasts these patterns were not evident. Moreover, differences between assemblages related to different environmental conditions were more evident in the shallower zone of distribution of the coralligenous habitat. This correlative study did not allow us to identify any cause-effect relationship, but patterns we detected agree with those of other studies, suggesting that alterations in the environmental conditions may be the cause of the decrease in differences among assemblages developing at different depths and may lead to a higher spatial homogenization and an impoverishment of the whole subtidal system.Este estudio investiga los patrones de distribución de las comunidades algales del hábitat coralígeno en relación a la profundidad y evalúa el papel de las diferentes condiciones ambientales en la formación de estos patrones. Se han muestreado dos profundidades (30 y 40 m) en pequeñas islas y en la costa continental. Los resultados muestran diferencias entre profundidades en la estructura de las comunidades entre islas, mientras que estas diferencias no son evidentes en el continente. Además las diferencias encontradas son más evidentes a 30 metros. Este estudio correlacional no nos permite establecer ninguna relación causa-efecto; sin embargo, los patrones detectados están de acuerdo con lo observado en otros trabajos, lo que sugiere que las alteraciones en las condiciones ambientales pueden ser la causa de la disminución de las diferencias entre comunidades que se desarrollan a profundidades distintas y pueden provocar una mayor homogeneidad espacial y un empobrecimiento de la zona sublitoral

Macroalgal assemblages as indicators of the ecological status of marine coastal systems: A review

Abstract Macroalgae have been utilized as biological indicators of ecosystem health in many monitoring programs worldwide. These programs have utilized various methods to quantify macroalgal community structures. The aim of this study was to provide an overview of current progress by reviewing techniques and methods in both monitoring programs and impact evaluation studies that use macroalgal assemblage data. A total of 215 papers were selected and divided into four categories: macroalgal assemblage monitoring, macroalgal mapping, developing and employing ecological indices based on macroalgae, and developing and employing generic ecological indices including macroalgae. The number and goals of macroalgal monitoring programs are very different among geographical areas. In Europe, the recent European Union Directives led to the development of indices as tool to monitor the ecological quality of coastal systems. In other geographic regions, most studies focused on mapping the distribution of kelps or Fucales. This demonstrates the necessity to harmonize marine macroalgal monitoring, identifying common metrics and approaches in sampling design, field measurements, taxonomic resolution and data management, in order to develop standardized procedures which may allow data obtained to be compared