Consumo de combustível na operação de subsolagem realizada antes e depois de diferentes sistemas de preparo periódico do solo

A subsolagem tem aumentado nos últimos anos de forma indiscriminada, faltando estudos que norteiem os melhores procedimentos para que novos problemas não sejam acrescentados devido a subsolagens inadequadas ou mesmo em solos onde a operação é desnecessária, e principalmente buscar redução no consumo de combustível. Dessa forma, este trabalho teve o objetivo de avaliar o consumo de combustível na operação de subsolagem efetuada antes e depois de diferentes sistemas de preparo periódico do solo, classificado como Nitossolo Vermelho distroférrico. Os preparos foram realizados com arado de discos, arado de discos mais uma gradagem de nivelamento, grade pesada, grade pesada mais gradagem de nivelamento e escarificador. A realização da subsolagem depois dos sistemas de preparo periódico requereu 15% menos de potência na barra de tração. A subsolagem depois dos diferentes sistemas de preparo economizou 16,5% de combustível por área. O deslizamento das rodas motrizes e a velocidade média operacional obtiveram melhor desempenho quando se realizou a subsolagem depois do preparo do solo.

Posicionamento e movimentação de um robô humanóide utilizando imagens de uma câmera móvel externa

This work proposes a method to localize a simple humanoid robot, without embedded sensors, using images taken from an extern camera and image processing techniques. Once the robot is localized relative to the camera, supposing we know the position of the camera relative to the world, we can compute the position of the robot relative to the world. To make the camera move in the work space, we will use another mobile robot with wheels, which has a precise locating system, and will place the camera on it. Once the humanoid is localized in the work space, we can take the necessary actions to move it. Simultaneously, we will move the camera robot, so it will take good images of the humanoid. The mainly contributions of this work are: the idea of using another mobile robot to aid the navigation of a humanoid robot without and advanced embedded electronics; chosing of the intrinsic and extrinsic calibration methods appropriated to the task, especially in the real time part; and the collaborative algorithm of simultaneous navigation of the robots

Implementação de rotinas computacionais básicas para cabeça estéreo robótica

O Laboratório de Sistemas Inteligentes do Departamento de Engenharia de Computação e Automação da Universidade Federal do Rio Grande do Norte - UFRN -tem como um de seus projetos de pesquisa -Robosense -a construção de uma plataforma robótica móvel. Trata-se de um robô provido de duas rodas, acionadas de forma diferencial, dois braços, com 5 graus de liberdade cada, um cinturão de sonares e uma cabeça estéreo. Como objetivo principal do projeto Robosense, o robô deverá ser capaz de navegar por todo o prédio do LECA, desviando de obstáculos. O sistema de navegação do robô, responsável pela geração e seguimento de rotas, atuará em malha fechada. Ou seja, sensores serão utilizados pelo sistema com o intuito de informar ao robô a sua pose atual, incluindo localização e a configuração de seus recursos. Encoders (sensores especiais de rotação) foram instalados nas rodas, bem como em todos os motores dos dois braços da cabeça estéreo. Sensores de fim-de-curso foram instalados em todas as juntas da cabeça estéreo para que seja possível sua pré-calibração. Sonares e câmeras também farão parte do grupo de sensores utilizados no projeto. O robô contará com uma plataforma composta por, a princípio, dois computadores ligados a um barramento único para uma operação em tempo real, em paralelo. Um deles será responsável pela parte de controle dos braços e de sua navegação, tomando como base as informações recebidas dos sensores das rodas e dos próximos objetivos do robô. O outro computador processará todas as informações referentes à cabeça estéreo do robô, como as imagens recebidas das câmeras. A utilização de técnicas de imageamento estéreo torna-se necessária, pois a informação de uma única imagem não determina unicamente a posição de um dado ponto correspondente no mundo. Podemos então, através da utilização de duas ou mais câmeras, recuperar a informação de profundidade da cena. A cabeça estéreo proposta nada mais é que um artefato físico que deve dar suporte a duas câmeras de vídeo, movimentá-las seguindo requisições de programas (softwares) apropriados e ser capaz de fornecer sua pose atual. Fatores como velocidade angular de movimentação das câmeras, precisão espacial e acurácia são determinantes para o eficiente resultado dos algoritmos que nesses valores se baseiam

Localização de um robô móvel usando odometria e marcos naturais

Several methods of mobile robot navigation request the mensuration of robot position and orientation in its workspace. In the wheeled mobile robot case, techniques based on odometry allow to determine the robot localization by the integration of incremental displacements of its wheels. However, this technique is subject to errors that accumulate with the distance traveled by the robot, making unfeasible its exclusive use. Other methods are based on the detection of natural or artificial landmarks present in the environment and whose location is known. This technique doesnt generate cumulative errors, but it can request a larger processing time than the methods based on odometry. Thus, many methods make use of both techniques, in such a way that the odometry errors are periodically corrected through mensurations obtained from landmarks. Accordding to this approach, this work proposes a hybrid localization system for wheeled mobile robots in indoor environments based on odometry and natural landmarks. The landmarks are straight lines de.ned by the junctions in environments floor, forming a bi-dimensional grid. The landmark detection from digital images is perfomed through the Hough transform. Heuristics are associated with that transform to allow its application in real time. To reduce the search time of landmarks, we propose to map odometry errors in an area of the captured image that possesses high probability of containing the sought mark

Controle dinâmico de robôs móveis com acionamento diferencial

This work addresses the dynamic control problem of two-wheeled differentially driven non-holonomic mobile robot. Strategies for robot positioning control and robot orientating control are presented. Such strategies just require information about the robot con¯guration (x, y and teta), which can be collected by an absolute positioning system. The strategies development is related to a change on the controlled variables for such systems, from x, y and teta to s (denoting the robot linear displacement) and teta, and makes use of the polar coordinates representation for the robot kinematic model. Thus, it is possible to obtain a linear representation for the mobile robot dynamic model and to develop such strategies. It is also presented that such strategies allow the use of linear controllers to solve the control problem. It is shown that there is flexibility to choice the linear controller (P, PI, PID, Model Matching techniques, others) to be implemented. This work presents an introduction to mobile robotics and their characteristics followed by the control strategies development and controllers design. Finally, simulated and experimental results are presented and commented

Sistema de navegação para robôs móveis autônomos

The main task and one of the major mobile robotics problems is its navigation process. Conceptualy, this process means drive the robot from an initial position and orientation to a goal position and orientation, along an admissible path respecting the temporal and velocity constraints. This task must be accomplished by some subtasks like robot localization in the workspace, admissible path planning, trajectory generation and motion control. Moreover, autonomous wheeled mobile robots have kinematics constraints, also called nonholonomic constraints, that impose the robot can not move everywhere freely in its workspace, reducing the number of feasible paths between two distinct positions. This work mainly approaches the path planning and trajectory generation problems applied to wheeled mobile robots acting on a robot soccer environment. The major dificulty in this process is to find a smooth function that respects the imposed robot kinematic constraints. This work proposes a path generation strategy based on parametric polynomials of third degree for the 'x' and 'y' axis. The 'theta' orientation is derived from the 'y' and 'x' relations in such a way that the generated path respects the kinematic constraint. To execute the trajectory, this work also shows a simple control strategy acting on the robot linear and angular velocities

Modelagem linear e identificação do modelo dinâmico de um robô móvel com acionamento diferencial

This work presents a modelling and identification method for a wheeled mobile robot, including the actuator dynamics. Instead of the classic modelling approach, where the robot position coordinates (x,y) are utilized as state variables (resulting in a non linear model), the proposed discrete model is based on the travelled distance increment Delta_l. Thus, the resulting model is linear and time invariant and it can be identified through classical methods such as Recursive Least Mean Squares. This approach has a problem: Delta_l can not be directly measured. In this paper, this problem is solved using an estimate of Delta_l based on a second order polynomial approximation. Experimental data were colected and the proposed method was used to identify the model of a real robot

Controle de posição com restrição à orientação de um Veículo Aéreo Não-Tripulado tipo Quadrirrotor

Quadrotors aircraft are composed by four propellers mounted on four engines on a cross or x disposition, and, in this structure, the engines on the same arm spin in the same direction and the other arm in the opposite direction. By rotating each helix generates vertical upward thrust. The control is done by varying the rotational speed of each motor. Among the advantages of this type of vehicle can cite the mechanical simplicity of construction, the high degree of maneuverability and the ability to have vertical takeoffs and landings. The modeling and control of quadrirrotores have been a challenge due to problems such as nonlinearity and coupling between variables. Several strategies have been developed to control this type of vehicle, from the classical control to modern. There are air surveillance applications where a camera is fixed on the vehicle to point forward, where it is desired that the quadrotor moves at a fixed altitude toward the target also pointing forward, which imposes an artificial constraint motion, because it is not desired that it moves laterally, but only forwards or backwards and around its axes . This restriction is similar to the naturally existing on robots powered by wheels with differential drive, which also can not move laterally, due to the friction of the wheels. Therefore, a position control strategy similar to that used in this type of robot could be adapted for aerial robots like quadrotor. This dissertation presents and discusses some strategies for the control of position and orientation of quadrotors found in the literature and proposes a strategy based on dynamic control of mobile robots with differential drive, called the variable reference control. The validity of the proposed strategy is demonstrated through computer simulations

Desenvolvimento de solução para SLAM utilizando visão de teto

This work intends to show a new and few explored SLAM approach inside the simultaneous localization and mapping problem (SLAM). The purpose is to put a mobile robot to work in an indoor environment. The robot should map the environment and localize itself in the map. The robot used in the tests has an upward camera and encoders on the wheels. The landmarks in this built map are light splotches on the images of the camera caused by luminaries on the ceil. This work develops a solution based on Extended Kalman Filter to the SLAM problem using a developed observation model. Several developed tests and softwares to accomplish the SLAM experiments are shown in details

Espaço e subjetividade: estudo com ribeirinhos

Nesta pesquisa, investigamos as transformações vividas por uma comunidade afetada pela construção de uma usina hidrelétrica no rio Paraná. Utilizando procedimentos da etnografia, realizamos várias visitas à comunidade, reassentada numa vila planejada e construída para substituir a antiga vila que foi submersa. Estabelecemos contatos com os moradores mais antigos e produzimos, com eles, diálogos entabulados em situações diversas, como em visitas às próprias casas e rodas de conversa ocorridas nas calçadas. Nas falas dos ribeirinhos, a mudança do espaço é sentida como algo negativo, em todos os planos da vida. Ressentem-se da perda do rio, da pesca farta, da caça realizada nas matas, das terras férteis cultivadas nas barrancas, da socialidade e de toda produção de subjetividade que mantinham naquele lugar marcado pela proximidade com o rio e suas águas.

Antimicrobial and Cytotoxic Activity of Fruit Extract from Syzygium cumini (L.) Skeels

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Exame microbiológico de sorvetes não pasteurizados

Realizou-se exame microbiológico em 24 amostras de sorvetes não pasteurizados, todos preparados de maneira não industrial e à base de leite (creme, nata, chocolate), fabricados por 12 sorveterias diferentes da cidade de Araraquara, SP. Colheram-se duas amostras de cada sorveteria com intervalo de 15 dias entre as colheitas. Realizaram-se as seguintes provas: contagem de bactérias aeróbicas ou facultativas mesófilas e psicrófilas e de Staphylococcus aureus; determinação do Número Mais Provável (NMP) de coliformes totais e fecais e da presença de Salmonella. As técnicas utilizadas foram aquelas convencionalmente usadas para tais determinações. Não foi encontrada Salmonella em nenhuma das amostras e de cerca de 16,6% delas isolou-se Staphylococcus aureus. em proporções variáveis verificou-se a presença de microrgarnismos deteriorantes e daqueles indicadores de poluição de origem fecal.

Mutagenicity induced by the hydroalcoholic extract of the medicinal plant Plathymenia reticulata Benth

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Atividades preventivas realizadas pelos cirurgiões-dentistas do PSF de Natal-RN

Family Health Program (FHP) presents itself as a restructured model on basic cares besides having prevention practices and promotion in health as essential parts. According to that, the purpose of this study is to perceive which prevention practices in oral health are accomplished by the dentists from the FHP of Natal-RN as well as the way they have been developed, the knowledge basis to execute the procedure and the use of evaluation instruments by the dentists and by the Oral Health Co-Ordinator. A list of dentists participating on the FHP of Natal in March, 2006 (n= 91) was obtained so it was possible to formulate a structured interview. After excluding those with less than six months attending to the program, and considering the loss, eighty dentists got to be interviewed. It had questions about individual and group preventive procedures, sources of basement to develop the activities and to verify the impact and evaluation instruments. Besides that, an interview was made with the Oral Health Co-Ordinator about the evaluating process and the existence of a protocol as well as about document analysis in the Ambulatory Informations System Unique Health System (AIS-UHS), Information of Basic Care System and Pact of Recorder. The main individual activities consist on Oral Hygiene Orientation (87,5%) and Fluoridization (95%). Group activities remain at scholar groups acts(91,25%) being fluoridization done by 91,25% and educative activities by 86,25% mainly through speeches (61,25%).Orientations about oral cancer were detached on the aged group (39,96%)and hypertensive and diabetic group (19,51%), as well as integration with the health team was respectively 21,93% and 39,02%. Speeches and talk rounds are the main activities for aged, hypertensive and diabetics, and are also expressive to pregnant women. For pregnant women and babies group predominate hygiene and diet orientation. About the evaluation instruments 73,75% of the dentists do not consider their existence, despite 73,75% consider that actions have impact specially due to a increase of hygiene and decrease of caries index on the children. The main sources of basement are clinical experience (42,5%) and preparative courses (33,75%), only 7,5% mentioned population need and local reality. The Oral Health Co-Ordinator related the Attention Pact Recorder and records from the AIS - UHS as evaluation source but also detached the lack of epidemiologic surveying. She mentioned the increase of supervised brushing as a positive result and detached the hardness of the professional to act inside the family and as a team. The AIS-UHS records showed that fluoridization is more used individually and the supervised brushing is predominant as a group action, besides that educative activities at the Health Establishment predominate due to actions at the community. Facing the results, it was verified the act in different groups, special attention given to scholars, as well as focus the activities on caries giving less emphasis to other oral problems. Despite that, there was no epidemiologic instruments or data of the local reality to guide the actions and to be part of the planning and evaluation process

Nervos: rede de discursos e práticas de cuidado na atenção básica no município de Natal/RN

The Primary Health Care and one of its main strategies, the Family Health Strategy (ESF), are framed as the gateway to the Public Health System (SUS). Thus, most of the incident and prevalent health problems in the population attended should be solved at this level of care, including psychological suffering, and the so-called complaint of nerves. Nerves and nervous denote a complexity that is not always well comprehended by health workers, in such a way that the care to this kind of problem is usually inadequate. In this line of thought, the general objective of this study is to analyze the network of discourses and the care to the psychological suffering, expressed as nerves, in SUS daily Primary Health Care. Besides and more specifically, it aims at identifying the principles and guidelines of the Primary Health Care in mental health; to investigate health workers positioning before psychological suffering and complaints of nerves, and also analyze different actions and practices of care carried out in different Health Units towards complaints like nerves. Institutional Ethnography was the theoreticalmethodological perspective adopted for the work. This approach seeks to understand and analyze the institutional relationships in a particular context considering sociostructural influences and power relations, as well as daily discourses and practices. Based on interviews with health professionals, informal conversations and observations in six Health Units with ESF teams from different sanitary districts in Natal/RN, it was possible to check that the index of complaint of nerves is high. The referral to psychologists and psychiatrists, as well as the prescription of psychotropic drugs appear as the most common intervention at this level of care. In general, the participants complain that they have poor specialized knowledge about the theme of mental health. They face the problem of bad work conditions and the lack of institutional support, which make actions of illnesses prevention and health promotion even more difficult. Besides, there are different ongoing practices such as meetings for hypertensive and aged people, walk, visit, round-table discussions and community therapy. However, not all of these actions are aimed at the care of psychological suffering. It is observed that the Matrix Support, which is a methodological strategy of supervision and follow up forcases of mental health, hasn t been totally implemented in the municipal system, although it is a tool that has been used by psychologists in some Health Units in the city. It was also verified that the health care practices to the problem of nerves strongly depend on the professional s commitment with the PSF guidelines and on mental health policies, in addition to continued support, when available, from other professional who works as matrix supporter