Modelling the transient drainage of liquid in foams

Froth flotation is the largest tonnage separation process worldwide and is used for paper deinking, water purification and, particularly, mineral separation. One of the key aspects of the performance of flotation cells is the behaviour of the liquid within the froth, as it is crucial to the purity of the product and a major influence on the overall recovery. Nonlinearities in models for liquid motion in the froth make them complex to solve and existing numerical solutions have been in two dimensions at most. In order to predict the performance of industrial flotation cell designs, a three-dimensional solution for these equations is desirable. Moreover, the understanding of the process would be enhanced if a transient model were used to predict the dynamics of foam drainage. In this work, the equations for the liquid drainage have been rearranged in order to make them analogous to a compressible version of the Navier-Stokes equations, coupled to an equation of state. A model for predicting the movement of the flowing foam has also been developed, which is able to solve for the foam velocity in two and three dimensions. This has allowed the transient behaviour of liquid in flotation foams to be modelled using Fluidity, a general purpose finite element method code that allows simulations to be carried out on unstructured adaptive meshes. This is an important feature for improving the computational cost of modelling these systems, as there are boundary layers present in the process, whose size is independent of the scale of the flotation system being modelled. These models have allowed, for the first time, to carry out numerical investigations of drainage for arbitrary flotation tank geometries in up to three dimensions, and have been verified against analytical solutions and compared to laboratory scale experiments with satisfactory agreement

Tactical activism religion, emotion, and political engagement in gender transformative interventions

Amb el suport econòmic del Govern del País Basc 2017-2020 (Ref.: POS_2016_01_0022)This article examines religious leaders' engagements with gender transformative activism during prevention training workshops for sexual and gender-based violence. I draw on ethnographic fieldwork carried out in 2017 and 2018 in a South African NGO that promotes gender equality and human rights across Africa. My aim is twofold: to explore the tensions between the private and public dimensions of religious leaders' engagement with gender transformative activism; and to demonstrate how they navigate those tensions by co-creating an 'interstitial' language and social space that allows them to conform new emotional repertoires, meanings and practices that ought to transform their gendered relations. I argue that doing so enables leaders to become tactical when engaging with gender activism in adverse religious contexts. By acting in the form of tactical activism, they establish interstices where religious and secular stances on gender can intersect whilst at the same time coping with the difficulties of inducing change in the given patriarchal structures

Effects of even-aged forest management on early successional bird species in Missouri Ozark forest

The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.Title from title screen of research.pdf file viewed on (May 26, 2006)Includes bibliographical references.Thesis (M.S.) University of Missouri-Columbia 2005.Dissertations, Academic -- University of Missouri--Columbia -- Fisheries and wildlife.I examined the effect of different clearcut sizes on species richness, abundance, and reproductive success of five early successional birds: Yellow-breasted Chat (Icteria virens), Indigo Bunting (Passerina cyanea), White-eyed Vireo (Vireo griseus), Hooded Warbler (Wilsonia citrina), and Prairie Warbler (Dendroica discolor) in the Missouri Ozarks. Ten clearcut stands were surveyed. The stands ranged in size from 0.95 to 11.38 ha and were 5-7 years old post-cut at the time of the survey (2001-2003). A total of 41 bird species were recorded; of these, 12 were considered early successional specialists. A positive relationship between clearcut size and avian species richness was found (r2= 0.6975, P<0.05), indicating that the number of species was higher in larger clearcuts than in smaller openings. Clearcut size had a significant effect on the relative abundance on four of the five early successional species; Hooded Warbler abundance was not affected by clearcut size. Statistical analysis of reproductive success was difficult to achieve because of the low number of nests found (n= 51). My results suggest that even-aged treatments of different size in a large forest matrix had a positive effect on early successional birds. Implementation of even-aged practices in a forest-dominated landscape create habitat for early successional birds. Larger clearcuts, between 3 and 10 ha in size, sustained greater abundance of early successional birds and did not affected significantly mature forest bird species

Desenvolvimento de sistema de radiofrequência para identificação de cédulas monetárias e documentos

Orientador: Hugo Enrique Hernández-FigueroaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de ComputaçãoResumo: Este trabalho descreve o desenvolvimento de um sistema de radiofrequência, eficaz e de baixo custo, para identificação de cédulas monetárias e documentos com a intenção de evitar falsificações. O sistema proposto é baseado nas tecnologias de linha de microfita e RFID sem chip, porém, a identificação é feita através do contato do objeto com a leitora. Para que essa identificação ocorra, na leitora, ressoadores em formato espiral são dispostos próximos a uma linha de transmissão, cada ressoador representando um bit de dado, e ressoam livremente até que uma cédula ou documento seja colocada em contato e devidamente alinhada. Cada cédula ou documento deve possuir uma marca metálica impressa em camada interna, pois dificulta falsificações e as ondas eletromagnéticas conseguem atravessar o papel, de forma que cada marca defina o código binário de cada objeto, uma vez que essas marcas metálicas suprimem as ressonâncias dos ressoadores situados na leitora. Em outras palavras, as marcas metálicas transformam o estado do bit de dado, bit 0 ou 1, correspondendo aos estados de presença e ausência de ressonância, respectivamente. O sistema também tem potencial para aumento do volume de codificação de dados com a possibilidade do sistema ternário, quando as ressonâncias possuem três estados. Resultados de simulações e resultados de medições também são apresentados neste trabalhoAbstract: This work describes the development of a low-cost and efficient radiofrequency system for banknotes and documents identification intending to avoid counterfeiting. The proposed system is based on the microstrip and chipless RFID technologies; however, the identification is carried out through the contact of the object with the reader. In order to make this possible, the spiral resonators in the reader are placed next to a transmission line, each resonator represents a data bit, they resonate freely until a banknote or a document is placed and aligned properly. Each banknote or document must have a metallic mark printed on its inner layer, because it makes falsification difficult and the electromagnetic waves can cross the paper, in such a way that each metallic mark establishes a binary code. The metallic marks suppress the resonances of the resonators located in the reader. In other words, the marks can change the bits state, 0 or 1, corresponding to the presence and absence of resonance, respectively. The system also has the potential to increase the volume of data encoding with the possibility of the ternary system, when the resonances have three states. Simulation and measurement results are also presented in this workMestradoTelecomunicações e TelemáticaMestre em Engenharia ElétricaCAPE

Religion, emotions and social transformation along migratory processes. The cases of African church leaders in Spain and South Africa

221 p.Speeches developed by pastors on Pentecostal churches can commonly move closer a subjective emotional approach and a practical everyday life stories reshaping and incorporating actions and interpretations adapted to the needs of a glocalized religious community where global features are adapted to local needs (Robertson, 1995). For this purpose, ritualities work with a high capacity for socializing key emotions on integration and social cohesion processes, mainly related to self-esteem, interpersonal trust and loyalty. According to Barbalet (1996), these three social emotions are necessary on social construction of agency, cooperation and organization, respectively. This proposal aims to (1) shed light on the relationship between everyday practices, idiosyncrasies and religious experience; (2) to examine the role of migrant church leaders and their abilities on providing social-cognitive tools towards an emotional construction of a de-territorialised socio-religious community; and (3) to see how these issues are shaped by specific social-cultural contexts. In sum, it is proposed to seek for an understanding of inter-subjective religious experience and its re-socialising role in coping with migrants lives across south-north (Bilbao) and south-south (Johannesburg) migration routes. These facts seem to be of great importance in building world views and socialities that invigorate and shape migratory processes (collective and individual memory, migratory journey, settlement, racism, xenophobia) and social cohesion

Development of behaviors for a simulated humanoid robot

Mestrado em Engenharia de Computadores e TelemáticaControlar um robô bípede com vários graus de liberdade é um desafio que recebe a atenção de vários investigadores nas áreas da biologia, física, electrotecnia, ciências de computadores e mecânica. Para que um humanóide possa agir em ambientes complexos, são necessários comportamentos rápidos, estáveis e adaptáveis. Esta dissertação está centrada no desenvolvimento de comportamentos robustos para um robô humanóide simulado, no contexto das competições de futebol robótico simulado 3D do RoboCup, para a equipa FCPortugal3D. Desenvolver tais comportamentos exige o desenvolvimento de métodos de planeamento de trajectórias de juntas e controlo de baixo nível. Controladores PID foram implementados para o controlo de baixo nível. Para o planeamento de trajectórias, quatro métodos foram estudados. O primeiro método apresentado foi implementado antes desta dissertação e consiste numa sequência de funções degrau que definem o ângulo desejado para cada junta durante o movimento. Um novo método baseado na interpolação de um seno foi desenvolvido e consiste em gerar uma trajectória sinusoidal durante um determinado tempo, o que resulta em transições suaves entre o ângulo efectivo e o ângulo desejado para cada junta. Um outro método que foi desenvolvido, baseado em séries parciais de Fourier, gera um padrão cíclico para cada junta, podendo ter múltiplas frequências. Com base no trabalho desenvolvido por Sven Behnke, um CPG para locomoção omnidireccional foi estudado em detalhe e implementado. Uma linguagem de definição de comportamentos é também parte deste estudo e tem como objectivo simplificar a definição de comportamentos utilizando os vários métodos propostos. Integrando o controlo de baixo nível e os métodos de planeamento de trajectórias, vários comportamentos foram criados para permitir a uma versão simulada do humanóide NAO andar em diferentes direcções, rodar, chutar a bola, apanhar a bola (guarda-redes) e levantar do chão. Adicionalmente, a optimização e geração automática de comportamentos foi também estudada, utilizado algoritmos de optimização como o Hill Climbing e Algoritmos Genéticos. No final, os resultados são comparados com as equipas de simulação 3D que reflectem o estado da arte. Os resultados obtidos são bons e foram capazes de ultrapassar uma das três melhores equipas simuladas do RoboCup em diversos aspectos como a velocidade a andar, a velocidade de rotação, a distância da bola depois de chutada, o tempo para apanhar a bola e o tempo para levantar do chão. ABSTRACT: Controlling a biped robot with several degrees of freedom is a challenging task that takes the attention of several researchers in the fields of biology, physics, electronics, computer science and mechanics. For a humanoid robot to perform in complex environments, fast, stable and adaptable behaviors are required. This thesis is concerned with the development of robust behaviors for a simulated humanoid robot, in the scope of the RoboCup 3D Simulated Soccer Competitions, for FCPortugal3D team. Developing such robust behaviors requires the development of methods for joint trajectory planning and low-level control. PID control were implemented to achieve low-level joint control. For trajectory planning, four methods were studied. The first presented method was implemented before this thesis and consists of a sequence of step functions that define the target angle of each joint during the movement. A new method based on the interpolation of a sine function was developed and consists of generating a sinusoidal shape during some amount of time, leading to smooth transitions between the current angle and the target angle of each joint. Another method developed, based on partial Fourier Series, generates a multi-frequency cyclic pattern for each joint. This method is very flexible and allows to completely control the angular positions and velocities of the joints. Based on the work of developed by Sven Behnke, a CPG for omnidirectional locomotion was studied in detail and implemented. A behavior definition language is also part of this study and aims at simplifying the definition of behaviors using the several proposed methods. By integrating the low-level control and the trajectory planning methods, several behaviors were created to allow a simulated version of the humanoid NAO to walk in different directions, turn, kick the ball, catch the ball (goal keeper) and get up from the ground. Furthermore, the automatic generation of gaits, through the use of optimization algorithms such as hill climbing and genetic algorithms, was also studied and tested. In the end, the results are compared with the state of the art teams of the RoboCup 3D simulation league. The achieved results are good and were able to overcome one of the state of the art simulated teams of RoboCup in several aspects such as walking velocity, turning velocity, distance of the ball when kicked, time to catch the ball and the time to get up from the ground

Religiosidad y (re)producción audiovisual : representaciones sociales en sonidos e imágenes de un culto pentecostal africano

El uso etnográfico de la observación pretende el estudio de las prácticas en determinados contextos sociales, analizando para ello la conformación de los nexos entre individuo, grupo y espacio en su multiplicidad de significantes. Atendiendo a la importancia de actitudes y comportamientos de grupos de referencia en la producción de representaciones audiovisuales, abordamos el caso de una comunidad pentecostal de origen africano en Bilbao, caracterizada por una doble devoción: religiosa y audio-visual. Su adhesión ferviente a ambas prácticas se inscribe en una experiencia migratoria (doble, a su vez, pues concita emigración e inmigración), a tenor de la cual cobran importancia en la vida cotidiana ciertos rituales así como objetos de movilidad, entre los que se cuentan las propias fotografías y vídeos, así como la música, al proporcionar imágenes y sonidos no sólo de contacto sino también de reconocimiento.The ethnographic observation is used to study practices in certain social contexts by assessing the formation of links between individual, group, and space in its multiplicity of meanings. Considering the importance of attitudes and behaviours of reference groups in the production of visual representations, we address the case of a Pentecostal community of African origins in Bilbao, characterized by its double devotion: religious and audio-visual. Its fervent adherence to both practices is part the experiences of migration (emigration and immigration) in which important meaning is given to everyday life by rituals and mobile objects such as pictures and videos as well as music, images, and sounds of intercommunication and acknowledgemen

Efeitos de 3 meses de destreino em idosas.

Introdução: Os programas de exercício físico para idosos previnem a morbilidade e aumentam a qualidade de vida. Em Portugal, a maioria dos programas são oferecidos, sazonalmente, por camaras municipais, que para pouparem dinheiro, interrompem-nos no período do verão. Objetivos: Avaliar os efeitos de três meses de destreino, depois da participação de nove meses de exercício físico, em idosas. Métodos: 51 mulheres (com idades 68.22±9.12) participaram em programas de exercício supervisionados, sendo divididas em dois grupos: aulas de grupo (Grupo 1) e aulas de grupo mais atividades aquáticas (Grupo 2). Foram avaliadas no fim do programa de exercício e no final do período de destreino. Resultados: Depois do período de destreino, Grupo 1 aumentou a pressão arterial sistólica (p=0.009) e pressão arterial diastólica (p=0.005). A resistência dos membros inferiores e superiores (p=0.000 e p=0.000, respetivamente), a agilidade (p=0.002), o equilíbrio (p=0.029) e a capacidade aeróbia (p=0.002) diminuíram. O Grupo 2 aumentou a pressão arterial sistólica (p=0.021). A resistência dos membros inferiores e superiores (p=0.000 e p=0.000 respetivamente), agilidade (p=0.000) e capacidade aeróbia (p=0.003) diminuíram. Conclusão: Os resultados sugerem que 3 meses de destreino em idosas provocam a perda de capacidades funcionais e têm efeitos deletérios no perfil hemodinâmico.Financiamento: Projeto Parque de Ciência e Tecnologia do Alentejo - Laboratório de Investigação em Desporto e Saúde (ALENT-07-0262-FEDER-001883) financiada pelo QREN-InAlentejo.info:eu-repo/semantics/publishedVersio