Aproveitamento energético de uma planta de sulfatação

Pós-graduação em Engenharia Mecânica - FEG

Equações de diferenças: aplicações no ensino médio

Pós-graduação em Matemática em Rede Nacional - IBILCE

Estudo e análise de sistemas de refrigeração industrial integrados a plantas de processo químico

This work approaches the analysis of industrial refrigeration systems applied to a chemical processing industry that, in this case, consists of refrigeration machines, cooling tower system, cold water system and brine system. In this study it is highlighted the function and characteristics of different systems, including the main components, the most important features, their functionality and best practices. The motivation for this work is the fact that refrigeration systems are essential in many industrial processes, presenting a high energy consumption that is related to a significant parcel of production costs. It has aimed to understand the case studied in order to evaluate the energy efficiency of systems and to compare with Carnot efficiency and best available technologies. The assessment aims to identify irregularities, find opportunities and propose solutions that increases the performance of equipment and the overall system efficiency. Therefore, the studies intend to reduce the operation costs and generate gains for the company

Análise de um trocador de calor tipo serpentina de uma planta de hipoclorito de sódio

This study aims to analyze the capacity of a helical coil heat exchanger to reach the requested heat transfer rates by a sodium hypochlorite production process. This heat exchanger was installed in an experimental way in order to reuse a source of low-temperatures water in such a way to become a more economical alternative than the existing cooling tower. Firstly, the concepts related to the theory of heat transfer applicable to the case were introduced. Then, the mapping of the main information about the production process and the technical specification of the current cooling system equipment's was realized. Using the dimensions of the heat exchanger installed today as reference, the calculations for determining the ideal length of the coil to different flows of hot fluid were performed. Finally, it was concluded that the heat exchanger currently employed does not provide heat transfer rates required for the maximum flow rate value supported by the cooling tower

RB30-245 Water Supply and Sewage Disposal Systems for Farm Homes

When the well "goes dry" or when the windmill or pump breaks down, every one in the household immediately appreciates the value fo plenty of water. In other words, "You never miss the water until the well runs dry." Fortunately, in most sections of this state, plenty of pure water may be obtained by sinking wells of moderate depth, yet surprisingly few farm homes are supplied with running water in the kitchen even though the barn yards are equipped with hydrants and tanks. It is the purpose of this bulletin to present a number of water supply and sewage disposal systems which have been used in Nebraska and surrounding states and which add greatly to the comfort and convenience of the farm home.

Thermal Imagery Applied to Reducing Bird Hazards to Aircraft at Airports

Airports worldwide are at a disadvantage when it comes to being able to spot birds and warn aircrews about the location of flocks either on the ground or close to the airfield. Birds simply cannot be easily seen during the day and are nearly invisible targets for planes at night or during low visibility. Thermal imaging (infrared) devices can be used to allow ground and tower personnel to pinpoint bird locations day or night, thus giving the airport operators the ability to launch countermeasures or simply warn the aircrews. This technology is available now, though it has been predominately isolated to medical and military system modifications. The cost of these devices has dropped significantly in recent years as technology, capability, and availability have continued to increase. Davison Army Airfield (DAAF), which is located about 20 miles south of Ronald Reagan National Airport in Washington, DC, is the transient home to many bird species including an abundance of ducks, seagulls, pigeons, and migrating Canadian geese. Over the past few years, DAAF implemented a variety of measures in an attempt to control the bird hazards on the airfield. Unfortunately, when it came to controlling these birds on or near our runways and aircraft movement areas we were more reactive than proactive. We would do airfield checks several times an hour to detect and deter any birds in these areas. The deterrents used included vehicle/human presence, pyrotechnics, and the periodic use of a trained border collie. At the time, we felt like we were doing all we could to reduce the threat to aircraft and human life. It was not until a near fatal accident in October 1998, when we truly realized how dangerous our operating environment really was to aircraft at or near the airfield. It was at this time, we had a C-12 (twin-engine passenger plane) land on our primary runway at night. The tower cleared the aircraft to land, and upon touchdown to the runway the aircraft collided with a flock of geese. Neither the tower nor the crew of the aircraft saw the geese because they were obscured in the darkness. The end result was 12 dead geese and $374,000 damage to the C-12. Fortunately, there were no human fatalities, but it was painfully clear we needed to improve our method of clearing the runway at night and during low visibility conditions. It was through this realization that we ventured to the U.S. Army Communications and Electronics Command for ideas on ways to deal with our threat. It was through a sub-organization within this command, Night Vision Labs, that we realized the possibilities of modifying thermal imagery and infrared technology to detecting wildlife on airports.

Showing that Early Childhood Education Works: Lessons from Italy, China, and the USA

Lessons from around the world; What does it matter about early childhood education? Why the controversy about public support for early childhood education? What process or system should be used to determine what works in early education? Can the same process be used to improve services? What is the role of government? Alternatives: 1. Consumers should determine… (What happens when private choices drive the market for early childhood services?) Observed quality of care in four Midwestern states; Parent data: “All things considered, how would you grade the quality of the care your child is receiving from his/her current caregiver?” Role of government What is a Quality Rating System? Ten states have implemented statewide systems (e.g. Colorado, Kentucky, Oklahoma, North Carolina) Findings 2. Objective science should determine… Firm findings from empirical research 3. Something else is needed: Some differences between Italian and American models. Teacher action research (and documentation) from a Reggio-inspired preschool in South Korea by Misuk Kim. Teacher Action Research at the Ruth Staples CDL. Can we now answer our opening questions? What process or system should be used to determine what is best for young children? Can the same process be used to improve the quality of services? Conclusions: The free market does not work well to determine quality in early education and care; Licensing, accreditation, and quality rating systems can help improve the market; Empirical research is useful for measuring what works; Teacher action research (reflective practice) is necessary for fostering continuous quality improvement. The tower of quality.

Estudo e análise de sistemas de refrigeração industrial integrados a plantas de processo químico

This work approaches the analysis of industrial refrigeration systems applied to a chemical processing industry that, in this case, consists of refrigeration machines, cooling tower system, cold water system and brine system. In this study it is highlighted the function and characteristics of different systems, including the main components, the most important features, their functionality and best practices. The motivation for this work is the fact that refrigeration systems are essential in many industrial processes, presenting a high energy consumption that is related to a significant parcel of production costs. It has aimed to understand the case studied in order to evaluate the energy efficiency of systems and to compare with Carnot efficiency and best available technologies. The assessment aims to identify irregularities, find opportunities and propose solutions that increases the performance of equipment and the overall system efficiency. Therefore, the studies intend to reduce the operation costs and generate gains for the company

Análise de um trocador de calor tipo serpentina de uma planta de hipoclorito de sódio

This study aims to analyze the capacity of a helical coil heat exchanger to reach the requested heat transfer rates by a sodium hypochlorite production process. This heat exchanger was installed in an experimental way in order to reuse a source of low-temperatures water in such a way to become a more economical alternative than the existing cooling tower. Firstly, the concepts related to the theory of heat transfer applicable to the case were introduced. Then, the mapping of the main information about the production process and the technical specification of the current cooling system equipment's was realized. Using the dimensions of the heat exchanger installed today as reference, the calculations for determining the ideal length of the coil to different flows of hot fluid were performed. Finally, it was concluded that the heat exchanger currently employed does not provide heat transfer rates required for the maximum flow rate value supported by the cooling tower

Amazon Rainforest Exchange of Carbon and Subcanopy Air Flow: Manaus LBA Site-A Complex Terrain Condition

On the moderately complex terrain covered by dense tropical Amazon Rainforest (Reserva Biologica do Cuieiras-ZF2-02 degrees 36'17.1 '' S, 60 degrees 12'24.4 '' W), subcanopy horizontal and vertical gradients of the air temperature, CO2 concentration and wind field were measured for the dry and wet periods in 2006. We tested the hypothesis that horizontal drainage flow over this study area is significant and can affect the interpretation of the high carbon uptake rates reported by previous works at this site. A similar experimental design as the one by Tota et al. (2008) was used with a network of wind, air temperature, and CO2 sensors above and below the forest canopy. A persistent and systematic subcanopy nighttime upslope (positive buoyancy) and daytime downslope (negative buoyancy) flow pattern on a moderately inclined slope (12%) was observed. The microcirculations observed above the canopy (38 m) over the sloping area during nighttime presents a downward motion indicating vertical convergence and correspondent horizontal divergence toward the valley area. During the daytime an inverse pattern was observed. The microcirculations above the canopy were driven mainly by buoyancy balancing the pressure gradient forces. In the subcanopy space the microcirculations were also driven by the same physical mechanisms but probably with the stress forcing contribution. The results also indicated that the horizontal and vertical scalar gradients (e. g., CO2) were modulated by these micro-circulations above and below the canopy, suggesting that estimates of advection using previous experimental approaches are not appropriate due to the tridimensional nature of the vertical and horizontal transport locally. This work also indicates that carbon budget from tower-based measurement is not enough to close the system, and one needs to include horizontal and vertical advection transport of CO2 into those estimates.

Development of a supplier and purchase order management product/service under the 4PL logistics concept: a case study

Supply chain starts with a demand arisen and ends with material transport and delivery at its final destination. With this in mind, most of manufacturing, processors or distribution companies of consumer goods, spare parts and components for production, processing and finished goods, within national or international markets, may not have information and control over its supply chain performance. This article presents concept and logistics models evolution, purchase order and international supplier management, control tower and its logistics information systems. This also presents a real process implementation for a global high tech manufacturer company.

Applications of High Speed Configurable Logic Devices in Modern Particle Physics Experiments

Several activities were conducted during my PhD activity. For the NEMO experiment a collaboration between the INFN/University groups of Catania and Bologna led to the development and production of a mixed signal acquisition board for the Nemo Km3 telescope. The research concerned the feasibility study for a different acquisition technique quite far from that adopted in the NEMO Phase 1 telescope. The DAQ board that we realized exploits the LIRA06 front-end chip for the analog acquisition of anodic an dynodic sources of a PMT (Photo-Multiplier Tube). The low-power analog acquisition allows to sample contemporaneously multiple channels of the PMT at different gain factors in order to increase the signal response linearity over a wider dynamic range. Also the auto triggering and self-event-classification features help to improve the acquisition performance and the knowledge on the neutrino event. A fully functional interface towards the first level data concentrator, the Floor Control Module, has been integrated as well on the board, and a specific firmware has been realized to comply with the present communication protocols. This stage of the project foresees the use of an FPGA, a high speed configurable device, to provide the board with a flexible digital logic control core. After the validation of the whole front-end architecture this feature would be probably integrated in a common mixed-signal ASIC (Application Specific Integrated Circuit). The volatile nature of the configuration memory of the FPGA implied the integration of a flash ISP (In System Programming) memory and a smart architecture for a safe remote reconfiguration of it. All the integrated features of the board have been tested. At the Catania laboratory the behavior of the LIRA chip has been investigated in the digital environment of the DAQ board and we succeeded in driving the acquisition with the FPGA. The PMT pulses generated with an arbitrary waveform generator were correctly triggered and acquired by the analog chip, and successively they were digitized by the on board ADC under the supervision of the FPGA. For the communication towards the data concentrator a test bench has been realized in Bologna where, thanks to a lending of the Roma University and INFN, a full readout chain equivalent to that present in the NEMO phase-1 was installed. These tests showed a good behavior of the digital electronic that was able to receive and to execute command imparted by the PC console and to answer back with a reply. The remotely configurable logic behaved well too and demonstrated, at least in principle, the validity of this technique. A new prototype board is now under development at the Catania laboratory as an evolution of the one described above. This board is going to be deployed within the NEMO Phase-2 tower in one of its floors dedicated to new front-end proposals. This board will integrate a new analog acquisition chip called SAS (Smart Auto-triggering Sampler) introducing thus a new analog front-end but inheriting most of the digital logic present in the current DAQ board discussed in this thesis. For what concern the activity on high-resolution vertex detectors, I worked within the SLIM5 collaboration for the characterization of a MAPS (Monolithic Active Pixel Sensor) device called APSEL-4D. The mentioned chip is a matrix of 4096 active pixel sensors with deep N-well implantations meant for charge collection and to shield the analog electronics from digital noise. The chip integrates the full-custom sensors matrix and the sparsifification/readout logic realized with standard-cells in STM CMOS technology 130 nm. For the chip characterization a test-beam has been set up on the 12 GeV PS (Proton Synchrotron) line facility at CERN of Geneva (CH). The collaboration prepared a silicon strip telescope and a DAQ system (hardware and software) for data acquisition and control of the telescope that allowed to store about 90 million events in 7 equivalent days of live-time of the beam. My activities concerned basically the realization of a firmware interface towards and from the MAPS chip in order to integrate it on the general DAQ system. Thereafter I worked on the DAQ software to implement on it a proper Slow Control interface of the APSEL4D. Several APSEL4D chips with different thinning have been tested during the test beam. Those with 100 and 300 um presented an overall efficiency of about 90% imparting a threshold of 450 electrons. The test-beam allowed to estimate also the resolution of the pixel sensor providing good results consistent with the pitch/sqrt(12) formula. The MAPS intrinsic resolution has been extracted from the width of the residual plot taking into account the multiple scattering effect.

LBT AO system: tests and calibration

An Adaptive Optic (AO) system is a fundamental requirement of 8m-class telescopes. We know that in order to obtain the maximum possible resolution allowed by these telescopes we need to correct the atmospheric turbulence. Thanks to adaptive optic systems we are able to use all the effective potential of these instruments, drawing all the information from the universe sources as best as possible. In an AO system there are two main components: the wavefront sensor (WFS) that is able to measure the aberrations on the incoming wavefront in the telescope, and the deformable mirror (DM) that is able to assume a shape opposite to the one measured by the sensor. The two subsystem are connected by the reconstructor (REC). In order to do this, the REC requires a “common language" between these two main AO components. It means that it needs a mapping between the sensor-space and the mirror-space, called an interaction matrix (IM). Therefore, in order to operate correctly, an AO system has a main requirement: the measure of an IM in order to obtain a calibration of the whole AO system. The IM measurement is a 'mile stone' for an AO system and must be done regardless of the telescope size or class. Usually, this calibration step is done adding to the telescope system an auxiliary artificial source of light (i.e a fiber) that illuminates both the deformable mirror and the sensor, permitting the calibration of the AO system. For large telescope (more than 8m, like Extremely Large Telescopes, ELTs) the fiber based IM measurement requires challenging optical setups that in some cases are also impractical to build. In these cases, new techniques to measure the IM are needed. In this PhD work we want to check the possibility of a different method of calibration that can be applied directly on sky, at the telescope, without any auxiliary source. Such a technique can be used to calibrate AO system on a telescope of any size. We want to test the new calibration technique, called “sinusoidal modulation technique”, on the Large Binocular Telescope (LBT) AO system, which is already a complete AO system with the two main components: a secondary deformable mirror with by 672 actuators, and a pyramid wavefront sensor. My first phase of PhD work was helping to implement the WFS board (containing the pyramid sensor and all the auxiliary optical components) working both optical alignments and tests of some optical components. Thanks to the “solar tower” facility of the Astrophysical Observatory of Arcetri (Firenze), we have been able to reproduce an environment very similar to the telescope one, testing the main LBT AO components: the pyramid sensor and the secondary deformable mirror. Thanks to this the second phase of my PhD thesis: the measure of IM applying the sinusoidal modulation technique. At first we have measured the IM using a fiber auxiliary source to calibrate the system, without any kind of disturbance injected. After that, we have tried to use this calibration technique in order to measure the IM directly “on sky”, so adding an atmospheric disturbance to the AO system. The results obtained in this PhD work measuring the IM directly in the Arcetri solar tower system are crucial for the future development: the possibility of the acquisition of IM directly on sky means that we are able to calibrate an AO system also for extremely large telescope class where classic IM measurements technique are problematic and, sometimes, impossible. Finally we have not to forget the reason why we need this: the main aim is to observe the universe. Thanks to these new big class of telescopes and only using their full capabilities, we will be able to increase our knowledge of the universe objects observed, because we will be able to resolve more detailed characteristics, discovering, analyzing and understanding the behavior of the universe components.

Entwicklung eines Spektralradiometers zur Bestimmung von aktinischer Strahlung und Photolysefrequenzen in bewölkter Atmosphäre

In dieser Arbeit wird ein neu entwickeltes Spektralradiometer zur Messung des solaren aktinischen Strahlungsflusses, speziell bei bewölkter Atmosphäre, vorgestellt. Das Meßsystem benutzt ein spezielles neu entwickeltes optisches Empfangssystem mit winkelunabhängiger Empfindlichkeit über den gesamten Raum (4pisr). Das Spektrometer besteht aus einem Gitterspektrographen und einer CCD-Kamera als Detektor, wodurch die schnelle simultane Messung eines Wellenlängenbereiches von 300nm bis 660nm ermöglicht wird. Zudem können Spektren von drei Empfangssystemen gleichzeitig aufgenommen werden, was zur höhenaufgelösten Messung des aktinischen Flusses verwendet wird. Photolysefrequenzen von Ozon, Stickstoffdioxid, und anderen für die troposphärische Chemie interessanten Molekülen werden mit Literaturdaten des molekularen Absorptionsquerschnitts und der Quantenausbeute und dem gemessenen aktinischen Strahlungsfluß berechnet. Zudem werden anhand von Spektren des aktinischen Flusses, die bei der Feldmeßkampagne BERLIOZ (BERLIn OZonexperiment) und bei Feldmessungen an einem 107m hohen Turm auf einem Berg (753m NN, Hunsrück) aufgenommen wurden, die Effekte unterschiedlicher Bewölkungssituationen untersucht. Als Ergebnis dieser Arbeit wurden verschiedene wellenlängenabhängige Effekte deutlich: bei partieller Bewölkung ist der aktinische Fluß am Erdboden gegenüber dem wolkenfreien Fall teilweise reduziert, aber auch erhöht, wobei diese Effekte mit zunehmender Wellenlänge größer werden. Oberhalb von Wolken ist der aktinische Fluß gegenüber dem wolkenfreien Fall erhöht. Dieser Effekt nimmt mit abnehmender Wellenlänge zu.

Hybrid foundations for offshore wind turbines

Nowadays offshore wind turbines represents a valid answer for energy production but with an increasing in costs mainly due to foundation technology required. Hybrid foundations composed by suction caissons over which is welded a tower supporting the nacelle and the blades allows a strong costs reduction. Here a monopod configuration is studied in a sandy soil in a 10 m water depth. Bearing capacity, sliding resistance and pull-out resistance are evaluated. In a second part the installation process occurring in four steps is analysed. considering also the effect of stress enhancement due to frictional forces opposing to penetration growing at skirt sides both inside and outside. In a three dimensional finite element model using Straus7 the soil non-linearity is considered in an approximate way through an iterative procedure using the Yokota empirical decay curves.