Justificativa e Objetivos: Comparar as repercussões na mecânica respiratória e na troca gasosa em pacientes pediátricos submetidos à cirurgia ortopédica em posição lateral sob anestesia geral, utilizando-se dois modos de ventilação mecânica: controlada a volume (VCV) versus controlada a pressão (PCV), pois, em anestesia, o benefício de um modo em relação ao outro não está bem estabelecido. Método: Ensaio clínico randomizado, realizado entre julho de 2003 e junho 2005 envolvendo crianças (seis meses a 5 anos) submetidas à cirurgia de correção de pé torto congênito no Hospital de Clínicas de Porto Alegre. No modo VCV o volume corrente para se obter 10ml.kg-1 foi fixado. No modo PCV a pressão de pico inspiratória para se obter 10 ml.kg-1 foi fixada. Nos dois modos os pacientes recebiam PEEP 5cmH2O e relação I:E 1:2. Os grupos foram comparados quanto aos efeitos na mecânica ventilatória e na troca gasosa em 4 momentos ao longo da cirurgia com duração de 2 a 3 horas. Os testes t de Student, ANOVA, e Quiquadrado foram utilizados para comparar os grupos. Resultados: 37 cirurgias de correção de pé torto congênito entraram no estudo, sendo 18 no grupo VCV e 19 no PCV. Observou-se redução do volume corrente expirado ao longo da cirurgia em ambos grupos: VT em M1 ~119 ml enquanto em M4 foi ~113 ml (p=0,03), correspondendo a uma redução de 5% no VT ao longo da cirurgia. O número de intervenções (ajustes na freqüência respiratória) ao longo do tempo cirúrgico foi semelhante nos dois grupos. As demais variáveis não diferiram. Conclusões: durante anestesia geral, em crianças saudáveis, o modo ventilatório não influenciou a estabilidade cardioventilatória das crianças ao longo do tempo cirúrgico no presente estudo. / Objectives: To compare the repercussions on the respiratory mechanics and on the gaseous exchange of pediatric patients submitted to orthopedic surgery in lateral position under general anesthesia using two modes of ventilation: volume control ventilation (VCV) versus pressure control ventilation (PCV), because, in anesthesiology, the superiority of one over another is not well established. Methods: Randomized clinical trial, conducted from July of 2003 through June 2005, involving children (from 6 months to 5 years of age) submitted to surgery of correction of congenital clubfoot in the Hospital de Clínicas de Porto Alegre. In the VCV mode, tidal volume to get 10ml.kg-1 was fixed. In the PCV mode, peak inspiratory pressure to get 10 ml.kg-1 was fixed. In the two ventilations modes the patients received a PEEP of 5cmH2O and relation I:E 1:2. The groups were compared in relation to the effect in the mechanical ventilatory support and the gaseous exchange at 4 times through surgery with duration of 2 the 3 hours. Student t Test, ANOVA, and Qui-square had been used to compare the groups. Results: 37 surgeries of correction of congenital clubfoot were included in study, being 18 in the VCV group and 19 in the PCV. Reduction of the exhaled tidal volume along of the surgery in both groups was observed: VT M1 ~119 ml while in M4 was ~113 ml (p=0,03), corresponding to a reduction of 5% in the VT through the surgery. The number of interventions (adjustments in the respiratory frequency) along the surgical period was similar in the two groups. Remaining variables had not differed. Conclusions: In the present study, envolving healthy children submitted to the general anesthesia using two modes of mechanical ventilation, we did not observed any interferency in the cardio respiratory stability along the surgical period.

Made available in DSpace on 2014-12-17T14:56:01Z (GMT). No. of bitstreams: 1 JoseKCO_DISSERT.pdf: 2360607 bytes, checksum: ad43aaed1b6651cd3d8e3ffe4e2f5b67 (MD5) Previous issue date: 2012-05-04 / The sanitation companies from Brazil has a great challenge for the XXI century: seek to mitigate the rate of physical waste (water, chemicals and electricity) and financial waste caused by inefficient operating systems drinking water supply, considering that currently we already face, in some cases, the scarcity of water resources. The supply systems are increasingly complex as they seek to minimize waste and at the same time better serve the growing number of users. However, this technological change is to reduce the complexity of the challenges posed by the need to include users with higher quality and efficiency in services. A major challenge for companies of water supplies is to provide a good quality service contemplating reducing expenditure on electricity. In this situation we developed a research by a method that seeks to control the pressure of the distribution systems that do not have the tank in your setup and the water comes out of the well directly to the distribution system. The method of pressure control (intelligent control) uses fuzzy logic to eliminate the waste of electricity and the leaks from the production of pumps that inject directly into the distribution system, which causes waste of energy when the consumption of households is reduced causing the saturation of the distribution system. This study was conducted at Green Club II condominium, located in the city of Parnamirim, state of Rio Grande do Norte, in order to study the pressure behavior of the output of the pump that injects water directly into the distribution system. The study was only possible because of the need we had to find a solution to some leaks in the existing distribution system and the extensions of the respective condominium residences, which sparked interest in developing a job in order to carry out the experiments contained in this research / As empresas de saneamento do Brasil t?m um grande desafio para o s?culo XXI, procurar diminuir o ?ndice de desperd?cios f?sicos (?gua, produtos qu?micos e energia el?trica) e financeiros causados pela inefici?ncia operacional dos sistemas de abastecimento de ?gua pot?vel, levando-se em considera??o que atualmente j? se enfrenta, em alguns casos, a escassez dos recursos h?dricos. Os sistemas de abastecimento est?o cada vez mais complexos porque buscam minimizar os desperd?cios e ao mesmo tempo atender melhor ao crescente n?mero de usu?rios. Contudo, a evolu??o tecnol?gica est? presente para diminuir a complexidade dos desafios hora impostos pela necessidade de contemplar os usu?rios com maior qualidade e efici?ncia nos servi?os. Um dos grandes desafios para as empresas de abastecimento de ?gua est? em proporcionar um servi?o de boa qualidade contemplando a diminui??o das despesas com energia el?trica. Diante disso, desenvolveu-se um trabalho de pesquisa atrav?s de um m?todo que busca controlar a press?o da rede de distribui??o em sistemas que n?o apresentam na sua configura??o o reservat?rio e, por isso a ?gua sai do po?o diretamente para a rede de distribui??o. O m?todo de controle da press?o (controle inteligente) utiliza a l?gica fuzzy para eliminar o desperd?cio de energia el?trica e os vazamentos provocados pela produ??o das bombas que injetam diretamente na rede de distribui??o, provocando desperd?cio de energia quando o consumo das resid?ncias ? reduzido causando o saturamento da rede. Esse trabalho foi realizado no condom?nio Green Club II, situado na cidade de Parnamirim - RN, com o objetivo de estudar o comportamento da press?o da bomba que injeta diretamente na rede de distribui??o. O estudo s? foi poss?vel em virtude da necessidade que havia de se encontrar uma solu??o para alguns vazamentos existentes na rede de distribui??o e nos ramais das resid?ncias do respectivo condom?nio, fato que despertou o interesse em desenvolver um trabalho com o intuito de realizar as experi?ncias contidas nesta pesquisa

Justificativa e Objetivos: Comparar as repercussões na mecânica respiratória e na troca gasosa em pacientes pediátricos submetidos à cirurgia ortopédica em posição lateral sob anestesia geral, utilizando-se dois modos de ventilação mecânica: controlada a volume (VCV) versus controlada a pressão (PCV), pois, em anestesia, o benefício de um modo em relação ao outro não está bem estabelecido. Método: Ensaio clínico randomizado, realizado entre julho de 2003 e junho 2005 envolvendo crianças (seis meses a 5 anos) submetidas à cirurgia de correção de pé torto congênito no Hospital de Clínicas de Porto Alegre. No modo VCV o volume corrente para se obter 10ml.kg-1 foi fixado. No modo PCV a pressão de pico inspiratória para se obter 10 ml.kg-1 foi fixada. Nos dois modos os pacientes recebiam PEEP 5cmH2O e relação I:E 1:2. Os grupos foram comparados quanto aos efeitos na mecânica ventilatória e na troca gasosa em 4 momentos ao longo da cirurgia com duração de 2 a 3 horas. Os testes t de Student, ANOVA, e Quiquadrado foram utilizados para comparar os grupos. Resultados: 37 cirurgias de correção de pé torto congênito entraram no estudo, sendo 18 no grupo VCV e 19 no PCV. Observou-se redução do volume corrente expirado ao longo da cirurgia em ambos grupos: VT em M1 ~119 ml enquanto em M4 foi ~113 ml (p=0,03), correspondendo a uma redução de 5% no VT ao longo da cirurgia. O número de intervenções (ajustes na freqüência respiratória) ao longo do tempo cirúrgico foi semelhante nos dois grupos. As demais variáveis não diferiram. Conclusões: durante anestesia geral, em crianças saudáveis, o modo ventilatório não influenciou a estabilidade cardioventilatória das crianças ao longo do tempo cirúrgico no presente estudo. / Objectives: To compare the repercussions on the respiratory mechanics and on the gaseous exchange of pediatric patients submitted to orthopedic surgery in lateral position under general anesthesia using two modes of ventilation: volume control ventilation (VCV) versus pressure control ventilation (PCV), because, in anesthesiology, the superiority of one over another is not well established. Methods: Randomized clinical trial, conducted from July of 2003 through June 2005, involving children (from 6 months to 5 years of age) submitted to surgery of correction of congenital clubfoot in the Hospital de Clínicas de Porto Alegre. In the VCV mode, tidal volume to get 10ml.kg-1 was fixed. In the PCV mode, peak inspiratory pressure to get 10 ml.kg-1 was fixed. In the two ventilations modes the patients received a PEEP of 5cmH2O and relation I:E 1:2. The groups were compared in relation to the effect in the mechanical ventilatory support and the gaseous exchange at 4 times through surgery with duration of 2 the 3 hours. Student t Test, ANOVA, and Qui-square had been used to compare the groups. Results: 37 surgeries of correction of congenital clubfoot were included in study, being 18 in the VCV group and 19 in the PCV. Reduction of the exhaled tidal volume along of the surgery in both groups was observed: VT M1 ~119 ml while in M4 was ~113 ml (p=0,03), corresponding to a reduction of 5% in the VT through the surgery. The number of interventions (adjustments in the respiratory frequency) along the surgical period was similar in the two groups. Remaining variables had not differed. Conclusions: In the present study, envolving healthy children submitted to the general anesthesia using two modes of mechanical ventilation, we did not observed any interferency in the cardio respiratory stability along the surgical period.

Justificativa e Objetivos: Comparar as repercussões na mecânica respiratória e na troca gasosa em pacientes pediátricos submetidos à cirurgia ortopédica em posição lateral sob anestesia geral, utilizando-se dois modos de ventilação mecânica: controlada a volume (VCV) versus controlada a pressão (PCV), pois, em anestesia, o benefício de um modo em relação ao outro não está bem estabelecido. Método: Ensaio clínico randomizado, realizado entre julho de 2003 e junho 2005 envolvendo crianças (seis meses a 5 anos) submetidas à cirurgia de correção de pé torto congênito no Hospital de Clínicas de Porto Alegre. No modo VCV o volume corrente para se obter 10ml.kg-1 foi fixado. No modo PCV a pressão de pico inspiratória para se obter 10 ml.kg-1 foi fixada. Nos dois modos os pacientes recebiam PEEP 5cmH2O e relação I:E 1:2. Os grupos foram comparados quanto aos efeitos na mecânica ventilatória e na troca gasosa em 4 momentos ao longo da cirurgia com duração de 2 a 3 horas. Os testes t de Student, ANOVA, e Quiquadrado foram utilizados para comparar os grupos. Resultados: 37 cirurgias de correção de pé torto congênito entraram no estudo, sendo 18 no grupo VCV e 19 no PCV. Observou-se redução do volume corrente expirado ao longo da cirurgia em ambos grupos: VT em M1 ~119 ml enquanto em M4 foi ~113 ml (p=0,03), correspondendo a uma redução de 5% no VT ao longo da cirurgia. O número de intervenções (ajustes na freqüência respiratória) ao longo do tempo cirúrgico foi semelhante nos dois grupos. As demais variáveis não diferiram. Conclusões: durante anestesia geral, em crianças saudáveis, o modo ventilatório não influenciou a estabilidade cardioventilatória das crianças ao longo do tempo cirúrgico no presente estudo. / Objectives: To compare the repercussions on the respiratory mechanics and on the gaseous exchange of pediatric patients submitted to orthopedic surgery in lateral position under general anesthesia using two modes of ventilation: volume control ventilation (VCV) versus pressure control ventilation (PCV), because, in anesthesiology, the superiority of one over another is not well established. Methods: Randomized clinical trial, conducted from July of 2003 through June 2005, involving children (from 6 months to 5 years of age) submitted to surgery of correction of congenital clubfoot in the Hospital de Clínicas de Porto Alegre. In the VCV mode, tidal volume to get 10ml.kg-1 was fixed. In the PCV mode, peak inspiratory pressure to get 10 ml.kg-1 was fixed. In the two ventilations modes the patients received a PEEP of 5cmH2O and relation I:E 1:2. The groups were compared in relation to the effect in the mechanical ventilatory support and the gaseous exchange at 4 times through surgery with duration of 2 the 3 hours. Student t Test, ANOVA, and Qui-square had been used to compare the groups. Results: 37 surgeries of correction of congenital clubfoot were included in study, being 18 in the VCV group and 19 in the PCV. Reduction of the exhaled tidal volume along of the surgery in both groups was observed: VT M1 ~119 ml while in M4 was ~113 ml (p=0,03), corresponding to a reduction of 5% in the VT through the surgery. The number of interventions (adjustments in the respiratory frequency) along the surgical period was similar in the two groups. Remaining variables had not differed. Conclusions: In the present study, envolving healthy children submitted to the general anesthesia using two modes of mechanical ventilation, we did not observed any interferency in the cardio respiratory stability along the surgical period.

In pneumatic pressure control applications the influence of tubes that connect the valve with the control volume ist mainly neglected. This can lead to stability and robustness issues and limit either control performance or tube length. Modeling and considering tube behavior in controller design procedure allows longer tubes while maintaining the required performance and robustness properties without need for manual tuning. The author\'s previously published Simplified Fluid Transmission Line Model and the proposed model-based controller design enable the specification of a desired pressure trajectory in the control volume while the pressure sensor is mounted directly at the valve. Thus wiring effort is reduced as well as cost and the chance of cable break or sensor disturbance. In order to validate the simulated results the proposed control scheme is implemented on a real-time system and compared to a state-of-the-art pressure regulating valve

Robot arms require actuators that are powerful, precise and safe. The safety concern is amplified when these robots work closely with people in collaborative applications. This thesis investigates the design and implementation of hybrid pneumatic-electric actuators (HPEA) for use in robot arms, particularly those intended for collaborative applications. The initial focus was on improving the control of an existing single HPEA-driven rotary joint. The torque is produced by four pneumatic cylinders connected in parallel with a small DC motor. The DC motor is directly connected to the output shaft. A cascaded control system is designed that consists of an outer position control loop and an inner pressure control loop. The pressure controller is based on a novel inverse valve model. High precision position tracking control is achieved due to the combination of the model-based pressure controller, model-based position controller, adaptive friction compensator and offline payload estimator. Experiments are performed with the actuator prototype rotating a link and payload with a rotational inertia equivalent to a linear actuator moving a 573 kg mass. Averaged over five tests, a root-mean-square error of 0.024° and a steady-state error (SSE) of 0.0045° are achieved for a fast multi-cycloidal trajectory. This SSE is almost ten times smaller than the best value reported for previous HPEAs. An offline payload estimation algorithm is used to improve the control system’s robustness. The superior safety of the HPEA is shown by modeling and simulating a constrained robot-head impact, and comparing the result with equivalent electric and pneumatic actuators. This research produced two journal papers. Since HPEAs are redundant actuators that combine the large force, low bandwidth characteristics of pneumatic actuators with the large bandwidth, small force characteristics of electric actuators, the effect of using optimization-based input allocation for HPEAs was studied. The goal was to improve the HPEA’s performance by distributing the required input (force or torque) between the redundant actuators in accordance with each actuator’s advantages and limitations. Three novel model-predictive control (MPC) approaches are designed to solve the position tracking and input allocation problems using convex optimization. The approaches are simulated on a HPEA-driven system and compared to a conventional linear controller without active input allocation. The first MPC approach uses a model that includes the dynamics of the payload and pneumatics; and performs the motion control using a single loop. The latter methods simplify the MPC law by separating the position and pressure controllers. Although the linear controller is the most computationally efficient, it is inferior to the MPC-based controllers in position tracking and force allocation performance. The third MPC-based controller design demonstrated the best position tracking with root mean square errors of 46%, 20%, and 55% smaller than the other three approaches. It also demonstrated sufficient speed for real-time operation. This research produced one journal paper. The research continued with the design and implementation of a two degree-of-freedom HPEA-driven arm. A HPEA-driven “elbow” joint is designed and added to the existing “shoulder” joint. The force from a single pneumatic cylinder is converted into torque using a 4-bar linkage. To eliminate backlash and keep the weight of the arm low, a 2nd smaller DC motor is directly connected to the joint. The kinematic and kinetic models of the new arm, as well as the geometry of the new elbow joint are studied. The resulting joint design is implemented, tested and controlled. This joint could achieve a SSE of 0.0045° in spite of its nonlinear joint geometry. The arm is experimentally tested for simultaneous tracking control of the two joints, and for end-effector position tracking in Cartesian space. The end-effector is able to follow a circular trajectory in pneumatic mode with position errors below 0.005 m. / Thesis / Doctor of Philosophy (PhD) / Robots that work with, or near, humans require greater safety considerations than other robots. A significant concern is collisions between the robot and humans that may happen when sensors or software fails. An actuator for robots that combines the inherent safety of pneumatic actuators with the accuracy of electric actuators, termed a “hybrid pneumatic electric actuator” (HPEA), is investigated. The design, instrumentation, modelling, and control of HPEAs are studied theoretically and experimentally. The proposed actuator could achieve high position control accuracy in a variety of experiments, with steady state error of less than 0.0045 degrees. Simulated impacts with a human head also showed that a HPEA-driven robot arm can achieve a 52% lower impact force, compared to an arm driven by conventional electric actuators. The HPEA design and control experiments are performed on a single HPEA-driven joint and extended to an arm consisting of two HPEA-driven revolute joints.

No / Experimental observations of melt temperature profiles and melting performance of extruder screws are reported. A novel temperature sensor consisting of a grid of thermocouple junctions was used to take multiple temperature readings in real time across melt flow in a single screw extruder. Melt pressure in the die and power consumption were also monitored. Three extruder screws at a range of screw speeds were examined for a commercial grade of low density polyethylene. Results showed melt temperature fields at low throughputs to be relatively independent of screw geometry with a flat-shaped temperature profile dominated by conduction. At high throughputs, melting performance and measured temperature fields were highly dependent upon screw geometry. A barrier-flighted screw with Maddock mixer achieved significantly better melting than single flighted screws. Low temperature "shoulder" regions were observed in the temperature profiles of single-flighted screws at high throughput, due to late melting of the solid bed. Stability of the melt flow was also dependent upon screw geometry and the barrier-flighted screw achieving flow with lower variation in melt pressure and temperature. Dimensionless numbers were used to analyze the relative importance of conduction, convection, and viscous shear to the state of the melt at a range of extrusion conditions.

Thesis (M. Tech. - (Engineering: Electrical, Department: Electronic Engineering, Faculty of Engineering and Technology))--Vaal University of Technology. / Industrial countries, such as South Africa, rely heavily on energy sources to function profitably in today’s economy. Based on the 2008 fossil fuel CO2 emissions South Africa was rated the 13th largest emitting country and also the largest emitting country on the continent of Africa, and is still increasing. It was found that fuel cells can be used to generate electricity and that hydrogen is a promising fuel source. A fuel cell is an energy generation device that uses pure hydrogen (99.999%) and oxygen as a fuel to produce electric power. A regenerative fuel cell is a fuel cell that runs in reverse mode, which consumes electricity and water to produce hydrogen. This research was aimed at designing and constructing an optimised control system to control the hydrogen pressure in a proton exchange membrane regenerative fuel cell. The hydrogen generated by the fuel cell must be stored in order to be used at a later stage to produce electricity. A control system has been designed and constructed to optimise the hydrogen pressure control in a regenerative proton exchange membrane fuel cell. An experiment that was done to optimise the hydrogen system included the effects that the cathode chamber pressure has on the production of hydrogen and the most effective method of supplying hydrogen to a storage tank. The experiment also included the effects of a hydrogen buffer tank on the output hydrogen pressure and if the system can accommodate different output pressures. It was found that the cathode chamber pressure doesn’t need to be controlled because it has no effect on the rate of hydrogen produced. The results also showed that the flow of hydrogen need not to be controlled to be stored in a hydrogen storage tank, the best method is to let the produced hydrogen flow freely into the tank. The hydrogen produced was also confirmed to be 99.999% pure. The system was also tested at different output pressures; the control system successfully regulated these different output pressures.

Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2017-04-20T13:29:23Z No. of bitstreams: 1 2016 - Rafael Veloso Patr?cio.pdf: 9711857 bytes, checksum: 5f7e5b198769c9a633040fd42126df03 (MD5) / Made available in DSpace on 2017-04-20T13:29:23Z (GMT). No. of bitstreams: 1 2016 - Rafael Veloso Patr?cio.pdf: 9711857 bytes, checksum: 5f7e5b198769c9a633040fd42126df03 (MD5) Previous issue date: 2016-08-24 / Funda??o de Apoio a Pesquisa Cient?fica e Tecnol?gica da UFRRJ-FAPUR / Controling of downhole pressure is essential for a safety process of oil well drilling. In a permeable formation, fluids from reservoir come into the annulus region (wellbore) when the downhole pressure is below pore pressure, featuring a disorder called kick. Literature reports some mathematical models developed to predict the behavior of the wellbore in presence of gas kick, however, there are few works reporting control and experiments. By this reason, it was built an experimental plant in order to study system?s behavior during fluid inlet (gas) from reservoir to annulus, and then, sought to develop a control strategy able to mitigate this disorder, without shut-in the well. A strategy with reconfiguration of the control law feedback?feedforward was designed to reject disturbance (gas inlet in the annular), to ensure the drilling within the operating window. Parallelly,simulation studies were developed which are: the construction of mathematical model, validated by the employment of the experimental unit, and the implementation of control based on reconfiguration of control law. / O controle da press?o anular de fundo ? fundamental para que a perfura??o de po?os de petr?leo seja feita de forma segura. Em uma forma??o perme?vel, fluidos do reservat?rio migram para a regi?o anular quando a press?o anular de fundo est? abaixo da press?o de poros, caracterizando o dist?rbio denominado kick. A literatura reporta alguns modelos matem?ticos desenvolvidos para prever o comportamento do po?o na presen?a de kick de g?s, por?m poucos s?o os trabalhos abordando controle e experimentos. A partir desta motiva??o, foi constru?do uma planta experimental para estudar o comportamento do sistema durante a entrada de fluido (g?s) do reservat?rio no anular, e assim, buscou-se desenvolver uma estrat?gia de controle que mitigue tal dist?rbio sem a necessidade do fechamento total do po?o. Uma estrat?gia com reconfigura??o da lei de controle feedback?feedforward foi desenvolvida para rejeitar a perturba??o (entrada de g?s no anular), visando assegurar a perfura??o dentro da janela operacional. Paralelamente, foram desenvolvidos estudos de simula??o quais sejam: a constru??o de um modelo matem?tico, validado empregando-se a unidade experimental, e a implanta??o de controle baseado em reconfigura??o da lei de controle

No description available.