Signatures of quark deconfinement through the r-modes of twin stars

The observation and distinction of two compact stars with an identical mass but a different radius would be a clear sign of hadron-quark phase transition in nuclear matter. Motivated by studies searching for significant deviations in the observables of twin stars, we investigate the differences that manifest in their r-mode instability windows and spin-down evolution. Firstly, we obtain a set of hybrid equations of state (which predict the existence of a third stable branch of compact objects) by employing the well-known Maxwell construction within the phenomenological framework of constant speed of sound parametrization. Then, we systematically study the influence of certain parameters, such as the energy density jump (in the resulting hybrid equation of state) and the crust elasticity, on the deviations appearing in the r-mode instability windows and spin-down evolution of twin stars. We conclude that two stars with an identical mass and fairly similar spin frequency and temperature, may behave differently with respect to r-modes. Thus, the future possible detection of gravitational waves (due to unstable r-modes) from a star laying in the stable region of the frequency-temperature plane would be a strong indication for the existence of twin stars. Furthermore, we consider current data for the spin frequencies and temperatures of observed pulsars and compare them to the predictions made from equations of state employed in this study. We find that, depending on the transition density and the rigidness of the crust, hybrid equations of state may be a viable solution for the explanation of existing data.Comment: v1: 14 pages, 7 figures, 2 tables; v2: updated to match the published version; accepted for publication in Physical Review

Contra-rotating propellers

Thesis (Nav. E. and S.M. in Mechanical Engineering)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2010.Cataloged from PDF version of thesis.Includes bibliographical references (p. 87-89).Improvement of the propulsive efficiency of ships has always been one of the main objectives for naval architects and marine engineers. Contra-Rotating propellers (CRP) are propulsor configurations offering higher efficiency compared to conventional single propellers by recovering the rotational energy in the propeller slipstream. The application of this type of propulsive device to modern ships becomes even more attractive, considering the recent developments in electric propulsion and the increased emphasis on fuel economy. Propeller design codes are therefore expected to include CRP design capabilities. This thesis describes two methods for designing CRP in the context of lifting-line theory, along with a procedure for predicting the cavitation performance of conventional propellers and CRP. All of the above methods have been implemented numerically and integrated into a computer program developed in MATLAB®. Comparisons of numerical predictions of efficiency between single and contra-rotating propellers, which confirm the superiority of the latter are presented. Physical insight into the increased efficiency of CRP is also obtained by presenting results for the velocity fields induced by these propulsor configurations. In addition, the predicted cavitation patterns, observed on conventional and contra-rotating propellers operating in uniform and non-uniform wakes, show the advantage of CRP with respect to the occurrence of cavitation.Dimitrios Laskos.Nav.E.and S.M.in Mechanical Engineerin

Aggressive saliency-aware point cloud compression

The increasing demand for accurate representations of 3D scenes, combined with immersive technologies has led point clouds to extensive popularity. However, quality point clouds require a large amount of data and therefore the need for compression methods is imperative. In this paper, we present a novel, geometry-based, end-to-end compression scheme, that combines information on the geometrical features of the point cloud and the user's position, achieving remarkable results for aggressive compression schemes demanding very small bit rates. After separating visible and non-visible points, four saliency maps are calculated, utilizing the point cloud's geometry and distance from the user, the visibility information, and the user's focus point. A combination of these maps results in a final saliency map, indicating the overall significance of each point and therefore quantizing different regions with a different number of bits during the encoding process. The decoder reconstructs the point cloud making use of delta coordinates and solving a sparse linear system. Evaluation studies and comparisons with the geometry-based point cloud compression (G-PCC) algorithm by the Moving Picture Experts Group (MPEG), carried out for a variety of point clouds, demonstrate that the proposed method achieves significantly better results for small bit rates

Ações e políticas públicas de ordenamento fundiário no meio rural

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias, Programa de Pós-Graduação em Agroecossistemas, Florianópolis, 2014.A diversidade de trabalhadores pertencentes ao segmento da agricultura familiar se faz importante para a formulação de políticas públicas pelo Estado brasileiro. Inclusos nessa categoria, trabalhadores rurais como posseiros, sem terras, arrendatários e parceiros se diferenciam pelo fato de não possuírem título de propriedade. A Secretaria de Reordenamento Agrário (SRA), vinculada ao Ministério do Desenvolvimento Agrário (MDA) coordena dois programas correlacionados a esse tema: Programa Nacional de Crédito Fundiário (PNCF) e o Programa de Cadastro de Terras e Regularização Fundiária. Já o Instituto Nacional de Colonização e Reforma Agrária (INCRA) foca suas ações em assentamentos rurais, mas também atua com regularização fundiária. Além de trabalhar com o acesso à terra, essas políticas buscam ordenar o meio rural fundiário, porém não apresentam indicativos que possam, de fato, reorganizar o espaço rural. Além disso, o pré-requisito fundamental para praticar as ações de ordenamento, o cadastro rural, não apresenta até o momento bases de dados confiáveis. A elaboração deste estudo contou com o auxílio de teorias referentes ao ordenamento territorial e fundiário e teve como objetivo analisar as ações e políticas públicas de ordenamento fundiário no meio rural e as possíveis contribuições do Sistema Nacional de Cadastro Rural no campo brasileiro. Os resultados da pesquisa demonstraram que, apesar das políticas analisadas serem ações importantes para milhares de agricultores com acesso precário à terra, elas apresentam inúmeras fragilidades de concepção e operacionais. O PNCF, a reforma agrária via desapropriação e a regularização fundiária estão contribuindo para reordenar o espaço rural de forma lenta, pois não estão sendo aplicados com o objetivo principal de ordená-lo, e sim como uma ferramenta de acesso à terra de famílias de agricultores. Apesar disso, esforços estão sendo conduzidos para melhorar o conhecimento da malha fundiária rural e o andamento das próprias políticas de acesso à terra e ordenamento fundiário já praticadas no país. A criação de dois sistemas eletrônicos de gestão de terras, mesmo que semelhantes, já produzem resultados práticos como o aumento no número de certificações e mais segurança para os cartórios na hora de registrarem modificações referentes aos estabelecimentos rurais.Abstract : The diversity of workers belonging to the segment of family farming is important for the formulation of public policies by the Brazilian state. Included in this category, rural workers, landless and others distinguished by the fact that they do not have title to the property. The Department of Agrarian Remanagement (SRA), under the Ministry of Agrarian Development (MDA) coordinates two programs related to this issue: National Land Credit Program (PNCF) and the Program for Land Cadastre and Land Regularization. Meanwhile, INCRA focuses its actions in rural settlements and also works with regularization. Besides working with land access, these policies seek to organize rural land, but have no codes that may indeed rearrange the countryside. Moreover, the prerequisite fundamental for the actions of planning, the rural cadastre, has no reliable databases for practice. The development work in theory had the help of theories concerning the territorial and land use planning and aimed to analyze the National Rural Cadastre System and its possible contribution in the process of land management in rural areas. The survey data showed that despite the policies analyzed are important actions that provide land access to thousands of farmers, they suffer from defects and not yet modified the agrarian structure of rural areas. The PNCF, the land reform through expropriation and land tenure are contributing to reorder rural areas slowly because they are not being implemented with the main objective of ordaining him, but as a tool of access to land and maintenance of family farming in the countryside. Nevertheless, efforts are being conducted to improve the knowledge of rural land mesh and the progress of their own policies regarding access to land and land planning practiced in the country. The creation of two systems of land management, even if similar, produce practical results as an increase in the number of certifications and more security for the notary at the time of registering changes of rural establishments

Σεισμική στρωματογραφία του Στρυμονικού Κόλπου, του Κόλπου του Ορφανού και του Κόλπου της Ιερισσού, Βόρειο Αιγαίο, Ελλάδα

Στην παρούσα πτυχιακή εργασία, έχοντας δεδομένα τρεις σεισμικές τομές από το Βόρειο Αιγαίο, δυτικά της Θάσου και συγκεκριμένα από τον Κόλπο του Ορφανού, της Ιερισσού και του Στρυμόνα, παρουσιάζεται η εξέλιξη και η στρωματογραφική ανάλυση των περιοχών αυτών. Κύριος σκοπός είναι η σεισμοστρωματογραφική ανάλυση των σεισμικών τομών και ο διαχωρισμός σε σεισμικές ακολουθίες με βάση τις προηγούμενες γεωλογικές μελέτες που έχουν γίνει τόσο σε ξηρά όσο και θάλασσα. Η συσχέτιση των στρωματογραφικών ευρημάτων στην λεκάνη του Στρυμόνα με αυτών στον κόλπο του Ορφανού, ακόμα και με τη λεκάνη του Πρίνου, είναι αναγκαία καθώς μόνο έτσι είναι δυνατή η πληρέστερη εικόνα για την εξέλιξη της περιοχής μελέτης. Κύριο ρόλο στην κατανόηση των δομών που κυριαρχούν στους δύο αυτούς κόλπους, έχουν οι επαφές άνω Μειόκαινου-Πλειόκαινου, η διαβρωμένη επιφάνεια του Μεσσήνιου δηλαδή, καθώς και η επαφή Πλειόκαινου-Πλειστόκαινου σε συνδυασμό με τις πληροφορίες που έχουμε για την παλαιογεωγραφική εξέλιξη των Νεογενών λεκανών στην περιοχή. Στον Στρυμονικό Κόλπο παρατηρείται η εμφάνιση μεγάλου πάχους ιζημάτων, κάτω από την επιφάνεια διάβρωσης του Μεσσήνιου, παρόμοια με της λεκάνης του Πρίνου. Σε συνδυασμό με δομές downlap και περαιτέρω πληροφορίες μπορεί να αναφερθεί ότι το περιβάλλον απόθεσης ήταν ρηχής θάλασσας έως δελταϊκό κατά το Πλειόκαινο και αρχές Τεταρτογενούς. Τέλος, δεδομένου ότι η περιοχή μελέτης βρίσκεται αρκετά κοντά στη λεκάνη του Πρίνου, έχει ιδιαίτερο νόημα να μελετηθεί η πιθανότητα πετρελαιοφορίας και να γίνει αναφορά στο πετρελαϊκό σύστημα της περιοχής.In the following thesis, given the data we have from three seismic profiles from the North Aegean Sea, west of Thassos and specifically from the Orfanos, Ierissos and Strymonikos Gulfs, the evolution and stratigraphic analysis of these areas is presented. The main purpose is the seismo-stratigraphic analysis of the seismic profiles and the separation into seismic sequences based on previous geological studies, carried out both on land and at sea. The correlation of the stratigraphic findings in the Strymon basin with those in the Orfanos Gulf, and even with the Prinos basin, is necessary as only in this way a more complete picture of the evolution of the study area is possible. The major role in understanding the structures dominating these two gulfs is played by the Upper Miocene-Pliocene,i.e. the erosional surface of the Messinian, and Pliocene-Pleistocene contacts, in combination with the information we have on the paleogeographic evolution of the Neogene basins in the area. In the Strymonikos Gulf, the appearance of thick sediments under the Messinian erosional surface is observed, similar to the Prinos Basin. In combination with downlap structures and further information it can be suggested that the depositional environment was shallow marine to deltaic during the Pliocene and early Quaternary. Finally, given that the study area is located quite close to the Prinos basin, it makes particular sense to study the possibility of oil production and make reference to the petroleum system in the area

All UK electricity supplied by wind and photovoltaics – The 30–30 rule

Based on weather and electricity demand data for the period 1984–2013, we develop a system model based on energy balance to determine the size of photovoltaic and wind generation combined with energy storage to provide a firm power supply for Great Britain. A simple graphical methodology is proposed where the required wind and PV generation capacities can be read off from a “system configuration diagram” as a function of the available storage size. We show, by way of illustration, that a reliable supply would be produced by a system based on PV and wind generators generating some 30% more electrical energy (approximately 100TWh p.a.) than the current electricity supply system if supplemented with 30 days of storage. In terms of generation capacities, the current 82GW of principally thermal generation would then be replaced by about 150GW of wind turbines and 35GW of PV arrays

Orthodontic brackets friction changes after clinical use : a systematic review

To evaluate the bracket-wire friction force after clinical use. A systematic search of several electronic databases (PubMed, Embase, Web of Science, Scopus, The Cochrane Library, Lilacs and Google Scholar) without limitations regarding publication year or language, was performed. In-vitro studies analyzing the changes in friction force of orthodontic brackets before/after their clinical use were considered. Risk of Bias was assessed with Downs and Black checklist. All methodological features that could interfere in the results were specifically described. Seven studies satisfied the inclusion criteria and were included in the review. All 7 studies reported at least two groups (before and after clinical use). Friction force increased after intraoral aging in most of the studies. However, there is lack of good quality evidence in this research area. Brackets present increased surface roughness after clinical use, and consequently increased coefficient of friction (COF) and Friction Force. Further studies are necessary to obtain more reliable results

The National Rural Registration System: History, Current Limitations and Prospects for Environmental Conservation and Land Security

Os espaços rurais brasileiros desempenham papel importante na gestão das questões ambientais e sociais. Nestes espaços são tomadas decisões que afetam a conservação dos ecossistemas naturais remanescentes e a reprodução social das famílias de agricultores. O Brasil dispõe do Sistema Nacional de Cadastro Rural (SNCR), vinculado a um sistema de registro de imóveis que tem por objetivo dar segurança jurídica aos proprietários de imóveis, garantindo acesso a políticas públicas, além de possibilitar o planejamento do uso e da ocupação da terra e o monitoramento da legislação ambiental. No entanto, esse sistema cadastral é declaratório e grande parte das informações prestadas não são verificadas a campo pelas instituições públicas. Diante desse cenário, este artigo tem como objetivo reunir informações técnicas disponíveis na literatura a respeito do SNCR para analisar a sua utilização potencial como ferramenta de gestão socioambiental. Verificou-se que o sistema cadastral declaratório aplicado não permite que os dados cadastrais sejam utilizados para o planejamento e o monitoramento de políticas públicas socioambientais, dando margem a diversas fraudes associadas a pagamentos de impostos, mudanças de titularidade, acesso a crédito no sistema bancário, uso irregular de áreas públicas ou protegidas. É necessário que exista uma sólida base de dados oficiais sobre o território para que as instituições de gestão e os cartórios de registros de imóveis possam confrontar as informações prestadas pelos proprietários sobre os imóveis rurais para que o SNCR alcance seu objetivo.The Brazilian rural areas play an important role in the management of environmental and social issues. In these areas decisions are made  which affect the conservation of the remaining natural ecosystems and the social reproduction of farming families. Brazil has the National Rural Registration System (SNCR) linked to a land registry system that aims to give legal certainty for farms owners, ensuring access to public policies, and enabling the planning of the land’s use and occupation and monitoring of environmental legislation. However, this registration system is declaratory and much of the information provided is not confirmed by public institutions. Therefore, this article aims to gather technical information available in the literature about the SNCR to analyze its potential use as an environmental management tool. The declaratory registration system applied was found not to allow registration data to be used for planning and monitoring of social and environmental policies, leading to several scams associated with tax payments, changes of ownership, access to credit in the banking system, and irregular use of public or protected areas

Boas práticas de manipulação na merenda escolar da rede municipal de educação do município de Araguatins - TO

Trabalho apresentado no II Congresso Nacional do PROJETO RONDON, realizado em Florianópolis, SC, no período de 23 a 25 de setembro de 2015 - Universidade Federal de Santa Catarina.A alimentação é uma necessidade básica do ser humano, um fator primordial para o desenvolvimento corporal e intelectual. Deste modo, a merenda escolar deve oferecer alimentos que atendam necessidades nutricionais dos alunos durante sua permanência na escola, assim contribuindo para o desenvolvimento humano e aprendizagem e rendimento escolar. Atualmente a alimentação escolar é considerada uma das principais refeições do dia de muitas crianças, portanto é de extrema importância ter o máximo de cuidado ao manipular os alimentos oferecidos. Os cuidados com a merenda escolar devem ser realizados desde a escolha, a compra dos alimentos até a distribuição e elaboração. Os cuidados não devem somente ser realizados nas etapas de pré-preparo, preparo e pós-preparo dos alimentos, mas também na higiene pessoal do manipulador, a qual todos os indivíduo devem ter com o seu próprio corpo para conservar não só a sua saúde pessoal, mas também a saúde das demais pessoas. A higiene dos manipuladores é de extrema importância devido ao risco de contaminação cruzada que pode ocorrer nos alimentos, visto que, hoje a contaminação vem sendo uma das grandes preocupações dos órgãos governamentais devido ao alto índice de doenças transmitidas por alimentos que resultam em sérios danos a saúde dos consumidores e em alguns casos podem levar até a morte. Portanto foi realizada na cidade de Araguatins – TO uma oficina com as merendeiras e zeladoras das escolas municipais do município que teve como objetivo oferecer informações que auxiliassem os manipuladores a manusear os alimentos de forma correta para mantê-los saudáveis e seguros. Assim foi abordado como preparar um alimento saudável e seguro na merenda escolar, a importância do manipular os alimentos quanto a higiene pessoal, higienização de alimentos, utensílios e ambiente, conservação dos mantimentos. As atividades foram conduzidas com interações práticas entre ministrantes e ouvintes. Uma das maiores preocupações encontradas e abordadas pelos participantes foram a falta de recursos financeiros para as compras dos materiais básicos para higienização e o difícil acesso a água potável e luz em algumas comunidades e equipamentos para a refrigeração ao adequada dos alimentos. Assim o trabalho das merendeiras torna-se desafiador para a busca constante pela segurança e qualidade da merenda escolar. Com o trabalho conseguiu-se atingir o resultado de conscientização das necessidades básicas de higiene pessoal e alimentar nas merendeiras e zeladoras da cidade de Araguatins - TO, além da troca de informações das diferentes realidades que vivem as diferentes regiões do Brasil atualmente