Alumina ceramics in a wear test reacts with air humidity to form a film layer of aluminum hydroxide which acts as a lubricant. Increasing sliding test load and/or speed affects the tribofilm and changes the wear regim...
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Alumina ceramics in a wear test reacts with air humidity to form a film layer of aluminum hydroxide which acts as a lubricant. Increasing sliding test load and/or speed affects the tribofilm and changes the wear regime from mild to severe. The purpose of this work was to determine critical values of load and sliding speed for the wear regime transition under controlled atmosphere humidity, in a pin-on-disc test. The wear rate and the worn surface SEM image and roughness allowed to distinguish the mild and severe wear regime for different speed/load combinations so that the boundaries of mild wear region was determined. The boundaries were characterized by a narrow transition zone. The image analyses have shown distinct wear mechanisms as function of sliding speed and load.
In this study, the kinetic of biogas production was studied by performing a series laboratory experiment using rumen fluid of animal ruminant as inoculums. Cattle manure as substrate was inoculated by rumen fluid to t...
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In this study, the kinetic of biogas production was studied by performing a series laboratory experiment using rumen fluid of animal ruminant as inoculums. Cattle manure as substrate was inoculated by rumen fluid to the anaerobic biodigester. Laboratory experiments using 400 ml biodigester were performed in batch operation mode. Given 100 grams of fresh cattle manure was fed to each biodigester and mixed with rumen fluid by manure: rumen weight ratio of 1:1 (MR11). The operating temperatures were varied at room temperature and 38.5 oC. The cumulative volume of biogas produced was used to measure the biodigester performance. The research showed that the rumen fluid inoculated to biodigester gave significant effect to biogas production (P
The induction planar actuator (EPA) in study is an electromagnetic structure formed by a static ferromagnetic core with an aluminium plate that corresponds to the secondary, and a mover, also called primary;the latter...
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ISBN:
(纸本)9781424470594
The induction planar actuator (EPA) in study is an electromagnetic structure formed by a static ferromagnetic core with an aluminium plate that corresponds to the secondary, and a mover, also called primary;the latter comprehends two sets of three-phase windings that are orthogonal to each other. When they are fed by a three-phase ac excitation, a moving magnetic field is established;it can travel along the x-axis and the y-axis direction. The travelling magnetic field induces currents in the secondary;the interaction between those induced currents and travelling magnetic field produces a planar traction force responsible for the movement of the mover over the working area of the actuator. Induced currents and planar traction forces are studied by means of a finite element model, and experimental results are produced.
A fluidized bed based process is proposed to produce gas for thermoelectric applications. The process variables are modeled based on transport equations and the finite volume numerical approach is applied to discretis...
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A fluidized bed based process is proposed to produce gas for thermoelectric applications. The process variables are modeled based on transport equations and the finite volume numerical approach is applied to discretise the differential equations. Rate equations for momentum, energy and chemical species exchanges are proposed to model the interphase interactions. The model is tested to investigate the combustion of biomasses and high ash Brazilian coals. A dessulfurising bed is used to control the gas product and keep thermal stability of the reactor. Numerical and experimental results from a pilot scale reactor indicated that is possible to produce gas with quality compatible with the requirements of those for thermal generation with high combustion rates.
A model based on transport equations to simulate the mini blast furnace process is presented. The model is adapted to consider flex fuel and raw materials such as small coke, granular charcoal and self reducing agglom...
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A model based on transport equations to simulate the mini blast furnace process is presented. The model is adapted to consider flex fuel and raw materials such as small coke, granular charcoal and self reducing agglomerates. New features are introduced to account for low CO2 emissions conditions. Computational results indicted that is possible to operate the mini blast furnace with flexible granular raw material and self reducing agglomerates.
A fluidized bed based process is proposed to produce gas for thermoelectric applications. The process variables are modeled based on transport equations and the finite volume numerical approach is applied to discretis...
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A fluidized bed based process is proposed to produce gas for thermoelectric applications. The process variables are modeled based on transport equations and the finite volume numerical approach is applied to discretise the differential equations. Rate equations for momentum, energy and chemical species exchanges are proposed to model the interphase interactions. The model is tested to investigate the combustion of biomasses and high ash Brazilian coals. A dessulfurising bed is used to control the gas product and keep thermal stability of the reactor. Numerical and experimental results from a pilot scale reactor indicated that is possible to produce gas with quality compatible with the requirements of those for thermal generation with high combustion rates.
The determination of the main magnetic properties of permanent magnets usually requires sophisticated and expensive measuring systems. This work analyzes and proposes a low-cost system for the characterization of Rare...
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We use a systemic framework to investigate the en route mid-air collision that occurred in the clear afternoon Amazon sky in which 154 people lost their lives to understand how and why this tragedy *** our research me...
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We use a systemic framework to investigate the en route mid-air collision that occurred in the clear afternoon Amazon sky in which 154 people lost their lives to understand how and why this tragedy *** our research method we search for the mid-air collision antecedents traced through the concurrence of performances of the several actors(pilots and controllers) and their interaction with the contextual conditions of the several ATM *** and evidences,antecedents and consequences from this mid-air collision come from a wide range of public available *** sources include official government documents,congressional hearings,including controllers',pilots',and air traffic management authorities'testimonies,video tapes,audio tapes of many media centers,press releases,newspaper clippings,flight plans,regulations,maps,directives and so *** findings emphasize that small and normal variations in the system behavior embedded in the equipment,people and organizational daily functioning jeopardize the active problem-solving behavior needed in an air traffic control management system,highlighting how the day-to-day functioning of the system can make monitoring and awareness difficult,and shape the cognitive strategies and decisions trade offs that operators have developed to deal with overall system behavior.
The blast furnace process is the main supplier of hot metal in the steel industry. This process is massive user of carbon source materials as fuel and reducing agent. Recently the development of self-agglomerates has ...
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ISBN:
(纸本)9788577370320
The blast furnace process is the main supplier of hot metal in the steel industry. This process is massive user of carbon source materials as fuel and reducing agent. Recently the development of self-agglomerates has open the possibility of its direct use in mini blast furnace. This investigation aims to numerically simulate a mini blast furnace process operating with self-reducing agglomerates with low slag rate and high rates of pulverized biomass combined with oxygen injection and small coke as solid fuels. The model describes the mini blast furnace process as a counter current reactor of five phases interacting with one another. The solid phase considers small sinter, self-reducing pellets and briquettes as iron bearing materials and small coke as solid fuel charged from the top. The modeling is based on transport equations of momentum, energy and chemical species of each phase and the chemical reactions are modeled by semi-empirical equations. Model results are presented for global parameters and spatial distributions for temperature and composition for solid and gas phases. Smooth operational conditions were obtained for about 20% of self-reducing pellets combined with small sinter and coke in the burden materials. In addition, up to 100 kg/t of pulverized biomass could be injected in the mini blast furnace tuyeres.
Nowadays, there is a growing interest in telemedicine in Brazil, because the country is the fifth largest country in the world and there is a huge gap between the population size and the number of available doctors. I...
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Nowadays, there is a growing interest in telemedicine in Brazil, because the country is the fifth largest country in the world and there is a huge gap between the population size and the number of available doctors. Institutions and the government are considering solutions for the integration and availability of data produced by several different systems. In this paper we present a contribution that is characterized by an asynchronous replication strategy between distributed medical databases. The contribution, named PGR, is an enhancement to the postgreSQL database software that introduces lightweight asynchronous operations. In addition, we have implemented a multi-master engine with partial replication and hybrid fragmentation in order to allow interoperability between different telemedicine systems. Our early results indicate that the model and its implementation have reached a successful level in terms of performance and interoperability.
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