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Dissertations/Thesis

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2025

	Dissertations
1	GIOVANI POZZA AZONI Analysis of the drag and lift in a subsonic wind tunnel of the scramjet X-43 hypersonic technology demonstrator. Advisor : GEORGE SANTOS MARINHO COMMITTEE MEMBERS : GEORGE SANTOS MARINHO DOUGLAS DO NASCIMENTO SILVA PAULO GILBERTO DE PAULA TORO HEIDI KORZENOWSKI Data: Jan 14, 2025 Show Abstract Scramjet technology demonstrators aim to demonstrate aspirated hypersonic propulsion at hypersonic speeds, that is, 5 times the speed of sound at flight altitude. The design of these vehicles aims to adapt to thermal and structural aerodynamic efforts for speeds greater than Mach 5. A scramjet vehicle works only at hypersonic speeds, however, to leave an aerodrome and reach operating speed and altitude the vehicle must be accelerated by another aircraft or other form of propulsion. Therefore, a hypersonic vehicle like the X-43 goes through all stages of flight from rest, going through the subsonic, transonic, and supersonic speed regimes until reaching hypersonic speed. Although projects have a large team of professionals, Scramjet vehicle designers often ignore subsonic stability in projects at hypersonic speeds, but for a viable final project, stability and maneuverability at low (subsonic) speeds are crucial for a well-driven vehicle. , given that currently, there are only hypersonic vehicles for military purposes, there are studies predicting vehicles for transporting passengers. Little is known about the aerodynamic behavior of this vehicle in subsonic flight, therefore in this present study an aerodynamic analysis of the drag and lift forces in subsonic flight will be carried out on the geometry of NASA's Scramjet X-43 demonstrator on a scale of 1:3.7 in a closed wind tunnel at a cruising speed of 20 m/s to verify the predictions of this geometry for a stable flight with an angle of attack of 0°, that is, the aircraft axis perpendicular to the airflow.

2024

	Dissertations
1	ALEX MAXWELL SILVA NASCIMENTO FUNCTIONAL CAUSE ANALYSIS (FCA): A Tailoring of FMEA E FTA Advisor : GIULIANI PAULINELI GARBI COMMITTEE MEMBERS : GIULIANI PAULINELI GARBI FRANCISCO JOSÉ TARGINO VIDAL MARCOS AURELIO FERREIRA DOS SANTOS Data: Jun 24, 2024 Show Abstract The studies on satellites have progressed over the years, following technological advancements. As a result, the concept of small satellites, known as CubeSats, emerged, initially intended for academic purposes. However, these satellites gained prominence by assuming functions previously performed only by larger satellites. Despite this, CubeSats face significant challenges, such as low reliability in their missions, due to financial constraints, time limitations, and lack of experience among their developers, especially in academic projects. Faced with these challenges, there is a need for methods and tools that facilitate development and improve the reliability of these missions, considering their difficulties. The objective of this work is to present an adaptation of traditional failure analysis tools, FMEA and FTA, as a more agile alternative for project failure analysis, with a case study in the development of a CubeSat, aiming to simplify implementation and make the techniques more practical for teams with limited resources. The FCA has proven to be fully functional, as demonstrated in the case study, being as effective as traditional tools and providing a reduction of approximately 50% in the development stages and processes, thanks to its more objective and direct approach. In addition to the benefits obtained, the FCA has proven to be a tool of generic use, applicable to any project requiring an easy-to-use tool, with reduced application time and producing solid results, especially in teams with limited resources, thus promoting their success.
2	LUIZ SAMPAIO ATHAYDE NETO Aerodynamic heating of a capsule in atmospheric reentry Advisor : GEORGE SANTOS MARINHO COMMITTEE MEMBERS : GEORGE SANTOS MARINHO DOUGLAS DO NASCIMENTO SILVA PAULO GILBERTO DE PAULA TORO HEIDI KORZENOWSKI Data: Jun 28, 2024 Show Abstract Objects reentering the atmosphere travels at hypersonic speeds, a regime where air molecules are subject to the effects of high temperatures, such as: vibration, dissociation, and ionization. In this case, air cannot be treated as a calorically perfect gas. Aerodynamic heating is a predominant phenomenon in this speed regime, resulting from friction between air molecules and the surface of the object in atmospheric reentry. In the 1950s, aerodynamicists engineers studied this phenomenon, to predict the flight behavior of aircraft and rockets. This led to the development of theoretical and experimental methods that subsequently contributed to the beginning of space exploration. In the present work, these methods were used to estimate the aerodynamic heating of a space capsule, with blunt conical geometry, during atmospheric reentry. Seven points of the reentry trajectory were considered. To estimate the heating experienced at the stagnation point of the capsule, the method developed by Fay and Riddell (1958) was used. The method developed by Lees (1956) was used to estimate the heat distribution in the spherical and conical regions of the capsule. To do this, it was necessary to know the geometrical dimensions of the vehicle, the trajectory of the reentry flight, the thermodynamic properties of the atmosphere at the seven points of the trajectory chosen for analysis, normal shock wave relations, and isentropic relations. From this knowledge, it was possible to observe the behavior of thermodynamic properties and how they influenced aerodynamic heating throughout the seven points of the reentry trajectory.
3	TIAGO ALEIXO DE ARAÚJO Conceptual study of a symmetrical internal scramjet demonstrator with three ramps. Advisor : PAULO GILBERTO DE PAULA TORO COMMITTEE MEMBERS : PAULO GILBERTO DE PAULA TORO JOÃO CARLOS ARANTES COSTA JÚNIOR SANDI ITAMAR SCHAFER DE SOUZA HEIDI KORZENOWSKI Data: Jul 15, 2024 Show Abstract In this work, a conceptual study of an airbreathing propulsion system based on supersonic combustion (scramjet technology) of an aerospace vehicle flying at hypersonic speed of 2050 m/s at an altitude of 30 km was developed. The objective was to study a symmetrical internal configuration with three ramps in the compression section and compare it with the mixed external and internal configuration with three ramps and same turning angles. An analytical theoretical methodology (engineering approach) was applied using the oblique shock wave theory in the compression section, the Rayleigh theory of heat addition in one-dimensional flow, with constant area cross section, no considering fuel mass, in the combustion chamber, and the area ratio theory coupled with the Prandtl-Meyer expansion theory in the expansion section. The flow properties without fuel injection at the combustion chamber (power-off) and with hydrogen fuel injection, burning atmospheric air-hydrogen fuel, in the flow at supersonic speed (power-on), were analyzed. The atmospheric air captured by the inlet of the scramjet vehicle is compressed and decelerated to a condition of supersonic speed and a temperature higher than the spontaneous ignition temperature of the fuel. Considering power-off condition, the flow at the expansion section obtained a velocity lower than the flight speed, due to the increase in entropy. However, in the power-on condition, the combustion products of the atmospheric air-hydrogen fuel mixture provide an increase in the scramjet's flight speed, producing uninstalled thrust of 402.64N and specific impulse of 4164.02s. Finally, a performance analysis of the scramjet developed was carried out considering parameters such as propulsive efficiency, thermal efficiency and global efficiency.
4	LUCAS GAUDENCIO VIVACQUA Relativistic Effects and Geolocation Satellite Systems Advisor : JOSE HENRIQUE FERNANDEZ COMMITTEE MEMBERS : JOSE HENRIQUE FERNANDEZ DOUGLAS DO NASCIMENTO SILVA LEONARDO ANDRADE DE ALMEIDA RONNI GERALDO GOMES DE AMORIM Data: Jul 22, 2024 Show Abstract The greater stability of the atomic clocks in the new generation’s satellites and the improvements in corrections are enabling applications of navigation systems at activities of increasingly higher level precision. We’ve recently witnessed the launch of the latest GALILEO satellites, the completion of the QZSS constellation, and the new generations of GLONASS and Beidou. All this made the need to integrate the navigation satellite systems an even more pressing matter. Therefore old questions are brought back and it’s important to know how they should be addressed now from the perspective of a single integrated GNSS. This study approaches the relativistic effects on the onboard atomic clocks in all six navigation constellations in operation nowadays. Hence, we set out to find the temporal distortion for each one of the 118 vehicles in the following constellations: GPS (USA), GLONASS (Russia), GALILEO (EU), Beidou (China), IRNSS (India), and QZSS (Japan). Through the ephemeris data, extracted from the constellations almanacs and the analy- tical equations of Special and General relativity, we found a fixed and two periodic offsets, influenced by the orbit’s semi-major axis, eccentricity, and inclination. For GPS, e.g., the fixed offset is 445.6 ps for each second elapsed on the ground. More importantly, when considering each satellite individually, we found that deviations from the average can go up to about 50 nanoseconds per day. For PRN 21 of the same constellation, we found a periodic effect due to the orbit’s eccentricity with an amplitude of 56.6 ns with a period equal to the orbital one. i.e., depending on the satellite’s position within the orbit the clock might be offset up to 56.6 ns. This may impact applications requiring precisions of tens of meters. Among the six constellations, 38.9% of the satellites require corrections for precision in the order of meters. Yet another periodic effect was found, one caused by the Earth’s oblateness with a period of half the orbital one and an amplitude that, from MEO satellites, goes from 60 to 100 ps, and thus causes trouble for applications that require centimeter-level precision. These estimations help us better understand the importance of applying the correct relativistic corrections for specific applications.
5	EDEL MARY QUINN DE OLIVEIRA FIGUERÊDO PROTOTYPE OF A DRILLING DEVICE TO BE BOARDED IN A SEMIAUTONOMOUS VEHICLE FOR REMOTE SENSING Advisor : MARCELO BORGES NOGUEIRA COMMITTEE MEMBERS : MARCELO BORGES NOGUEIRA DOUGLAS DO NASCIMENTO SILVA PABLO JAVIER ALSINA FILIPE CAMPOS DE ALCANTARA LINS Data: Sep 24, 2024 Show Abstract This work presents the design of a semi-autonomous probe for environmental exploration, designed to collect and transmit data on soil variables. The project was designed considering a vehicle capable of moving semi-autonomously in areas with potential for desertification — such as the Brazilian Semi-Arid Region. The vehicle will operate as a Data Collection Platform, willing to work with the Brazilian Environmental Data Collection System, transmitting data via satellite and receiving data in a mission control center. The region to be monitored will be previously identified by satellite images, in which its georeferential coordinates will assist in locating the vehicle and mapping the local area; and the results of mapping and soil monitoring carried out by the vehicle will help characterize environments through data intercomparison. Among other features of the vehicle, the development of a drilling device (electric drill) stands out, to facilitate the penetration of sensors into the earth and measurement of soil parameters (soil moisture and salinity). Based on explorations using the vehicle, the possibility of supporting soil recovery and management projects is considered, enabling the sustainable use of land.
6	JÚLIO CÉSAR COSTA SANTOS Eccentricity behavior in subgiant binary stars under the influence of tidal forces Advisor : JEFFERSON SOARES DA COSTA COMMITTEE MEMBERS : JEFFERSON SOARES DA COSTA JOILSON BATISTA DE ALMEIDA REGO THARCISYO SA E SOUSA DUARTE Data: Nov 29, 2024 Show Abstract The circularization results presented by the subgiant binary stars are consistent with those reported by Mazeh et al. (2008). We did not find a significant difference in the eccentricity evolution between stars with radiative envelopes and massive envelopes. In total, we identified 123 subgiant binary stars out of 1,274,059 stars observed jointly by GAIA and Kepler. We used the DR2 data available on gaia-kepler.fan. Based on these data, we conducted an eccentricity analysis as a function of orbital period for 43 stars, and we analyzed the depth of the convective envelope and the evolution of eccentricity using the theories of Zahn and Verbunt for 38 stars. The results closely align with those found for main-sequence stars and red giants. Systems with short orbital periods tend to exhibit circular orbits, while systems with longer orbital periods tend to remain eccentric. We used Python programming language for the spectroscopic data analysis from Gaia to identify a group of stars belonging to the subgiant evolutionary branch. We employed the evolutionary tracks from Padova (Girardi) and TGEC. To define the eclipsing binary stars, we used the data from Kirk’s 2016 work, which was based on photometry.

2023

	Dissertations
1	MARCO ANTÔNIO VIEIRA DE REZENDE Activities and Geopolitical Actions Aimed at Technical-Scientific Education in the Space Sector Advisor : GIULIANI PAULINELI GARBI COMMITTEE MEMBERS : DINO LINCOLN FIGUEIROA SANTOS GIULIANI PAULINELI GARBI JOSE HENRIQUE FERNANDEZ MARCOS AURELIO FERREIRA DOS SANTOS Data: Jun 22, 2023 Show Abstract The world has undergone economic, political and social changes in a more intense and accelerated way since the beginning of the globalization of communications, with the advent of artificial satellites. These changes directly reflected on the dynamism of education despite the class model still being quite prescriptive and dogmatic, not encouraging students to become protagonists in the learning process. Interest in Science and Technology, as well as space exploration, is often related to subcultures that adopt specific entertainment media rather than actual scientific research as a vocational incentive. With few young people pursuing careers in math and science, there is a shortage of qualified professionals working in aerospace S&T. However, there are strong indications that it is possible to reverse this situation through innovative educational initiatives, some of which are already being implemented around the world. Believing that betting on young people is creating alternatives for a different world, various entities, public or private, in different countries, turned to the search for motivational and low-cost projects. Ludic activities and the STEAM methodology (Science, Technology, Engineering, Arts and Mathematics) present an interesting tool to help reverse the current situation and bring these students closer to Exact and Earth Sciences courses, as well as space activities. This dissertation presents, at first, the analysis of interesting models used worldwide. The STEAM model, with an operational focus, addresses activities aimed at stimulating curiosity, based on a new learning approach, which value multidisciplinarity in the classroom, as well as use practices in workshops aimed at the focus of “hands-on” activity. ”. The MANAGEMENT models, as an essential tool after the 1988 Constitution, are presented as beacons for a more efficient administrative-financial management. In a second moment, we sought, in the available literature, successful vocational-educational initiatives that could add positively to improving the model chosen by the Brazilian initiative. Some historical spending data on S&T and formal-informal education was also shown, with the aim of comparing some priorities around the world and, mainly, in Brazil. As a result, actions were proposed to boost the Brazilian space vocational project, with short, medium and long-term activities that arouse students' interest in space science and related technologies, focused on astronomy and space exploration.
2	THAÍS MILLA SIMÃO ARAÚJO Performance analysis of GMSK receivers for the Global Open Data Collector System (GOLDS) Advisor : FRANCISCO JOSÉ TARGINO VIDAL COMMITTEE MEMBERS : ANTONIO MACILIO PEREIRA DE LUCENA FRANCISCO JOSÉ TARGINO VIDAL GIULIANI PAULINELI GARBI Data: Sep 29, 2023 Show Abstract The Global Open CoLlecting Data System (GOLDS) is a satellite environmental data collection system proposed as an evolution the Brazilian Environmental Data Collecting System (SBCDA). The SBCDA signal is modeled with Phase Shift Keying (PSK) modula- tion and without channel encoding. One of the main problems of the SBCDA is inter-user interference. As the available bandwidth for reception is small, it is recommended that the frequency band occupied by the signals from Data Collection Platforms (PCD) be compact. In this context, with the aim of improving the spectral efficiency of PCD signals, GOLDS proposes the use of Gaussian Minimum Shift Keying (GMSK) modulation. Hence, the objective of this work is to evaluate synchronization and demodulation techniques for GMSK signals used in the GOLDS system. Three signal models were evaluated, and syn- chronization and demodulation techniques were presented to compose the receiver, followed by simulations to verify the system’s performance. The results showed an improvement in signal detection since inter-signals interference was reduced with the implementation of GMSK modulation. The MSK-type linear demodulator for the pre-coded GMSK signal demonstrated satisfactory performance for the system. As for timing and phase synchro- nization, some methods available in the literature were evaluated. Joint phase and timing estimation for MSK signals showed better performance for the GOLDS system.
3	ALEXANDER ALBERTO CAMACHO SOLANO scramjet vehicle conceptual design for ascendant flight from 21 km to 31 km into Earth's atmosphere Advisor : PAULO GILBERTO DE PAULA TORO COMMITTEE MEMBERS : DOUGLAS DO NASCIMENTO SILVA GEORGE SANTOS MARINHO HEIDI KORZENOWSKI PAULO GILBERTO DE PAULA TORO Data: Dec 18, 2023 Show Abstract This monograph presents a conceptual study, under development at the Universidade Federal do Rio Grande do Norte (UFRN), of a supersonic combustion demonstrator (scramjet technology), during atmospheric flight, in constant hypersonic velocity of 1950 m/s in the altitudes of 21 km, 26 km and 31 km. The analytical theories of the oblique shock wave, the heat addition in one-dimensional flow in the cross section with constant area and the area ratio were applied in the compression, combustion chamber and expansion, respectively, considering air as a perfect gas and without considering viscous effects. The compression section angles were determined by ensuring that the temperature (higher than the fuel ignition temperature) and the supersonic velocity of the atmospheric airflow provided the stoichiometric burning of atmospheric air and hydrogen fuel in the combustion chamber. Also, it was considered that the incident shock waves have the same intensity providing on-lip and on-corner shock conditions. The expansion section has been optimized considering the combustion products have the same pressure at the scramjet flight altitude. Finally, it was observed the combustion products, in the expansion section, were at a hypersonic velocity greater than the flight velocity of 1950 m/s, allowing the generation the not installed thrust.

2022

	Dissertations
1	WILLIAM HUMBERTO ÚSUGA GIRALDO Mask technique for detecting space debris with ground telescope images acquired in static mode Advisor : JOSE DIAS DO NASCIMENTO JUNIOR COMMITTEE MEMBERS : JOSE DIAS DO NASCIMENTO JUNIOR JEFFERSON SOARES DA COSTA LEANDRO DE ALMEIDA Data: Jan 31, 2022 Show Abstract Orbital debris of approximately 10 cm in size can be measured with ground-based telescopes. This debris threatens the functioning of satellites and has an impact on the economy and the global security of space activities. In the GEO orbit, where most of the economically active satellites are located, exists approximately 842 cataloged debris. On the other side, orbiting LEO exists approximately 13485 debris cataloged. In this context, the ESA studies show that hundreds of millions of small objects over 1 mm are currently in the two orbits GEO and LEO above the Earth and have not yet been cataloged. In this study, we created a computational procedure to detect space debris in GEO orbit based on images obtained from ground-based telescopes on the static mode. In this mode, the field sky stars appear as lines in the CCD images and the garbage in the form of dots. CCD images of 2992 x 2092 pixels (high resolution) and with 5 degrees of field of view (FOV) and with 7 seconds of exposure used in this work were obtained with the PanEOS telescope (Panoramic Electro-Optical System), 750 mm aperture, and installed at the Picos dos Dias observatory of the National Astrophysics Laboratory (LNA). For this research, we adapted the Photoutils package written in Python to build a mask and separate stars from candidates for space debris. Our methodology consisted of first smoothing the images using a Gaussian Kernel filter, then each element was categorized into two categories, and finally, the stars were erased resulting only in space debris candidates. We tested combinations of flow to establish the detection limit and used the different points spread function (PSF) to determine the limit of the elongation of objects. Our methodology works with a single image at a time in a fast and efficient way. This allows us to detect objects with different PSF and therefore requires low hardware capability. Our results in this validation phase identified 100% of the artificial training debris. In the real images of the PanEOS telescope, we detected a few real debris consistent with the expected size. In the next steps, we must estimate the size of the object and characterize its orbit.
2	JULIANA JENIFFER FERNANDES DE SOUZA RÊGO Ballistic armor design of the as-350 helicopter from numerical-experimental analyses. Advisor : DINO LINCOLN FIGUEIROA SANTOS COMMITTEE MEMBERS : DINO LINCOLN FIGUEIROA SANTOS JOSE DANIEL DINIZ MELO JOSÉ VIRGÍLIO GUEDES DE AVELLAR VIVIANE MUNIZ FONSECA Data: Feb 14, 2022 Show Abstract Helicopters used in public safety operations go through several risk situations involving ballistic projectiles, one of the safest solutions is armor, offering maximum protection combined with technology. The present work aims to project an armoring system for the AS-350 helicopter, using as material the polymer matrix composite reinforced with para-aramid fiber and glass fiber. Considering the airworthiness requirements and the restrictions determined by the manufacturer, an analytical method was used to study the effects of armor on the weight and balance of the aircraft. The project used the Aerospace Design Methodology in conducting the work. To verify the efficiency of the ballistic composite, the experimental tests were carried out in an open outdoor environment where the composite was exposed to the impact of projectiles with a caliber of 5.56x45 mm. The performance of the material was analyzed by the results obtained in the tests and, this provided the determination of the protection reliability of the ballistic system. The armor design for the AS-350 proved to be safe to be installed on aircraft of this model, as a level III ballistic protection tool, without impairing its mobility.
3	ELDER SAMUEL TAVEIRA DA SILVA PRELIMINARY DESIGN OF A NANOSATELLITE LAUNCH VEHICLE USING SCRAMJET TECHNOLOGY Advisor : DOUGLAS DO NASCIMENTO SILVA COMMITTEE MEMBERS : DOUGLAS DO NASCIMENTO SILVA JOSE HENRIQUE FERNANDEZ PAULO GILBERTO DE PAULA TORO JOÃO FELIPE DE ARAÚJO MARTOS Data: Feb 17, 2022 Show Abstract This Master's Dissertation presents a preliminary design of an aerospace vehicle, using hypersonic airbreathing propulsion based on supersonic combustion (scramjet technology), for atmospheric flight at 20 km altitude, at hypersonic speed, corresponding to Mach number 5.79. Scramjet is an aeronautical engine without moving parts, where the aerospace vehicle integrated with scramjet technology (propulsion system) must be coupled to a rocket engine. The current means of access to space is limited by the chemical propulsion system (solid and / or liquid fuel) carried onboard rockets. The technology of supersonic combustion (scramjet) is being studied as an airbreathing propulsion system, to be used in the dense layers of the Earth's atmosphere, to access space. A demonstrator is being designed to be coupled to the Sonda III rocket engine, to operate as a second stage, starting the operation at 20 km altitude. The theory of oblique shock waves, the theory of heat addition in one-dimensional flow (Rayleigh's theory) and the theory of expansion waves (by Prandtl-Meyer) coupled to the area ratio are applied in the design of the compression sections, of combustion and expansion, respectively, of the scramjet demonstrator with internal admission configuration. Steady state, one-dimensional flow and air under calorically perfect gas conditions will be considered. Thermodynamic properties (pressure, temperature, density, speed of sound) and flow velocity (Mach number) will be presented along the streamline from the leading edge to the trailing edge of the demonstrator, considering flow without and with boundary layer effects, for the conditions of no fuel burning (power-off) and fuel burning (power-on). Finally, the conceptual design and a brief approach to systems engineering in the development of a nanosatellite launch vehicle are presented.
4	MARCOS VINICIUS SABINO PEREIRA Preliminary design of a scramjet to insert cubesat into orbit Advisor : SANDI ITAMAR SCHAFER DE SOUZA COMMITTEE MEMBERS : DOUGLAS DO NASCIMENTO SILVA HEIDI KORZENOWSKI PAULO GILBERTO DE PAULA TORO SANDI ITAMAR SCHAFER DE SOUZA Data: Feb 19, 2022 Show Abstract In order to access the space through the application of hypersonic airbreathing propulsion technology, this work proposes the development of a scramjet (supersonic combustion ramjet). The aerospace vehicle proposed in this work will have three stages, two stages of rocket engines with solid propulsion and a stage composed by a scramjet with four combustion chambers. The scramjet of this vehicle will operate in vertical flight in the Earth’s atmosphere, from 20 km to 60 km of altitude with hypersonic speed corresponding to approximately Mach number 5.8. Bearing in mind that the scramjet has no moving parts and needs a system that accelerates it, up to supersonic combustion conditions, it will be necessary to use the accelerator vehicle that is responsible for propelling the scramjet to the ideal operating conditions (Mach number, position, dynamic pressure). This aerospace vehicle will have the utility of accessing space and conducting drilling experiments, injecting CubeSat into orbit and training the specialized labor responsible for aerospace operations. For the preliminary development of this work, it is necessary to use the theories referring to the formation of shock waves and expansion waves, in addition to the theories related to the addition of heat and the formation of a boundary layer in flow with hypersonic velocity. Therefore, for this development the analytical theoretical methodology was applied and then with the results obtained it was possible to carry out, in the near future, the preliminary mechanical design that determines the necessary basic measures, in addition to the possible materials to be used in the vehicle. The preliminary results of this work indicate that the scramjet will be able to generate thrust and that when considering the existence of the boundary layer, a change in the geometry of the vehicle's inlet is necessary, so that it is possible to maintain the formation of shock-on-lip and shock-on -corner in the scramjet structure.
5	ARTHUR BANDEIRA LUZ DE LIMA A study about the influence of the solar cycles in the atmospheric conditions over the Curitiba Flight Information Region Advisor : JOSE HENRIQUE FERNANDEZ COMMITTEE MEMBERS : DINO LINCOLN FIGUEIROA SANTOS FILIPE EMANUEL VIEIRA TAVEIROS JOSE HENRIQUE FERNANDEZ Data: Feb 21, 2022 Show Abstract Atmospheric conditions are mostly driven by the Sun, which follows a cycle of activity whose duration is about 11 years. Since this cycle has been found out, researchers has brought up the hypothesis that it may have some influence at the lower atmosphere, taking as proxies the Carbon-14 and Berilium-10 concentration in tree rings and ice cores. Beside that, some manuscripts have shown that, during the Maunder Minimum, where the Sun were at minimum of activity, some regions over the globe experienced a tiny "Ice Age". Initially, it was believed that this influence was related to the Total Solar Irradiation variation during a cycle. Although, further studies have shown that such variations were a rather small to produce these variations on the lower atmosphere. So, they have created the hypothesis that these influence was related to the solar cycle on the Galactic Cosmic Rays (GCR) flux through the heliosphere. GCR work as a ionizing agent, favoring the aerosol synthesis, which acts as Condensation Nuclei, which favors clouds formation. So, the objective of the research was to find a correlation between the solar cycles and meteorological conditions in the region where the cities of Rio de Janeiro e São Paulo are located. In this region, a huge flux of aircraft is observed.
6	BENJAMIM MONTEIRO DA SILVA NETO DEVELOPMENT A MOBILE PLATAFORM APP FOR THE RISK MANAGEMENT OF NANOSATELLITE PROJECTS Advisor : GIULIANI PAULINELI GARBI COMMITTEE MEMBERS : FRANCISCO JOSÉ TARGINO VIDAL GIULIANI PAULINELI GARBI MARCOS AURELIO FERREIRA DOS SANTOS Data: Feb 22, 2022 Show Abstract Within Systems Engineering, risk management processes are mandatory requirements in satellite missions, being used on a large scale for large satellites. However, traditional approaches need adaptations to be applied, in a viable way, to missions with small satellites due to the costs and deadlines involved. This work aims to design, implement, and disseminate a risk management methodology adapted to small satellites. To this end, it is proposed to create an application to perform this management, using the necessary adaptations for application to this type of mission. The bibliographic research methodology was used to characterize small satellites, mostly the CubeSat platform, and the description of methods and risk management tools used worldwide, as well as their applications to small satellite projects. For the design of the application, the Java language will be used. The application’s functionalities were chosen to provide agility, ease, and integration with the risk management processes. The work is divided into five chapters. The first one consists of an introduction. The second presents a historical reinterpretation of small satellites, definitions of them, and their importance. The third chapter deals with systems engineering and risk management. The fourth chapter presents examples of risk management adapted for nanosatellites. And the fifth chapter presents the proposed solution to the problem raised.
7	RAFAEL ALVES FREIRE Stellar Rotation Period Versus Energy Variation of Flares in TESS Stars of Spectral Types K and M Advisor : JOSE HENRIQUE FERNANDEZ COMMITTEE MEMBERS : JOSE HENRIQUE FERNANDEZ DOUGLAS DO NASCIMENTO SILVA JOSE RENAN DE MEDEIROS ANTONIO CARLOS DA SILVA MIRANDA Data: Feb 24, 2022 Show Abstract Under the development of new technologies, the Aerospace Engineering is increasinglyimproving its equipments in order to assist exploration that goes beyond our Heliopause.As an example of this we can cite the launch of the space artfact Transiting Exoplanet Survey Satellite(TESS) that has been contributing photometric data to Space Sciences, like Astrophysics,with the aim of study various physical phenomena. As an exemple, the magnetic activityof stars can be fundamental in forming the atmosphere of exoplanets and impact yourhabitability as well as, it can trigger life in the orbit of type K and M stars, which areconsidered to be cold and they are the most numerous in the main sequence phase inthe Hertzsprung-Russell diagram. Based on these investigations and through statisticalanalysis of the behavior of stellar flares in relation to their classi cations, rotational periodsand spectral subtype, this dissertation presents a study on the variation of energieof stellar flares as a function of their rotational period in a sample of 679 TESS stars ofspectral type K and M. None of the stars in this sample showed a correlation between theenergy of their surface stellar eruptions as a function of their rotational period. Finallywe present four scenarios involving the stars and their stellar eruptions and theirs thatcan explain our results.
8	THIAGO FONSECA MESSIAS Test of a UHF receiver to collect satellite sensor data Advisor : JOSÉ MARCELO LIMA DUARTE COMMITTEE MEMBERS : FRANCISCO DE ASSIS BRITO FILHO FRANCISCO JOSÉ TARGINO VIDAL JOSÉ MARCELO LIMA DUARTE Data: Feb 25, 2022 Show Abstract This master’s thesis presents a test plan, the automation system for carrying out theexperiments and the results obtained from the Environmental Data Collector (EDC), UHFreceiver for collecting data from satellite sensors. The parameters tested were: bandwidth,linearity, spurious, noise figure and performance of the decoding the received signals.The EDC will act in the space segment of the Brazilian Environmental Data CollectionSystem (SBCDA), a forwarding system for satellite message. For over twenty years, theSBCDA has provided data for various surveys. sas, however, the SBDCA needs an updateto its space segment. The Institute National Space Research Institute is developing aconstellation of nanosatellites from the CubeSat standard to replace the current SBCDAsatellites. The EDC will be the payload of the new SBCDA nanosatellites. To validatethe EDC, a test plan was prepared which aims to assess whether the prototype built is inaccordance with the desired specifications. To carry out the tests, a bench equipped with acomputer was built, equipped with testing software, a signal generator, a voltage sourceand a Arduino. A spectral analysis, from the digitized signal, was used for the tests. of theRF-Front-End and the Frame Error Rate calculation was used to validate the capacity ofthe EDC to decode incoming messages. The EDC prototype was approved with based onthe results obtained, however, some corrections were suggested.
9	JOÃO BATISTA DOLVIM DANTAS Antennas for the Long Distance Communication System for Unmanned Air Vehicle Advisor : FRANCISCO JOSÉ TARGINO VIDAL COMMITTEE MEMBERS : FILIPE EMANUEL VIEIRA TAVEIROS FRANCISCO JOSÉ TARGINO VIDAL GIULIANI PAULINELI GARBI JOSE PATROCINIO DA SILVA Data: Aug 29, 2022 Show Abstract Brazilian Space Launch Centers employ conventional aircraft to monitor large maritime areas destined to the impact point of rockets or parts of them, and this has a high cost. The remotely piloted aircraft (RPAs) have shown to be a low cost solution for operationsof this type, however, the short range of their conventional remote controls is a limiting factor for their employment in large distances.This paper proposes high-performance antennas for remotely piloted aircrafts (RPA) communication system, aiming control and image transmission from RPA operating at long distances. It was considered the case-study of the Brazilian Space Launch Centers,which plan to employ RPA in order to assist the surveillance of the restricted area for rocket impact. The proposed antennas were designed in order to maximize gain and lobe aperture for the ground station operation; whereas, for RPA operation, the antennas were tailored in order to provide optimal gain and omnidirectional transmission, even during RPA maneuvers, as well as to minimize weight, size and aerodynamic drag in the aircraft. It is minutely described the design and evaluation of the proposed antennas, by means of simulations and experimental verification. The radio link using the proposed antennas was evaluated in laboratory and verified able to perform data transmission at emulated distance of 110 km (59.4 NM)(68.35 M).
10	PAULO CÉSAR DE OLIVEIRA JÚNIOR Conception, design and structural analysis of a supersonic combustion demonstrator Advisor : JOÃO CARLOS ARANTES COSTA JÚNIOR COMMITTEE MEMBERS : GEORGE SANTOS MARINHO HEIDI KORZENOWSKI JOÃO CARLOS ARANTES COSTA JÚNIOR PAULO GILBERTO DE PAULA TORO Data: Dec 14, 2022 Show Abstract ABSTRACT In the current scenario of the aerospace sector, there is a great limitation related to the payload that can be launched into orbit or beyond. Rocket engines, propulsive technology in operation, have a low specific impulse compared to systems with airbreathing propulsion (scramjet technology) that use atmospheric air as an oxidant. During hypersonic flight, aerospace vehicles with hypersonic airbreathing propulsion are subject to high aerodynamic and thermal loads. In this context, in the present work the main objective is to perform a structural analysis of a generic supersonic combustion demonstrator, under flight conditions at an altitude of 23 km and speed corresponding to Mach 5,8. To carry out the structural analysis, an aerodynamic and dimensional design of a generic scramjet was carried out, designed for coupling to the national rocket engines S30 and S31. Optimization criteria were applied to the compression section, aiming to achieve the required temperature and Mach number conditions at the entrance of the combustion chamber to spontaneously burn hydrogen. In the expansion section, the optimization criterion is based on checking the point at which the pressure condition is equivalent to that of free flow, defining the region where the coupling to the accelerator vehicle must be carried out. The aerodynamic load was defined from analytical and numerical aerodynamic analysis, considering air as a calorically perfect gas and neglecting viscous effects. The design and aerodynamic analysis evaluated the case without fuel burning (power-off) and with fuel burning (power-on), but in the structural analysis only power-on was considered. Numerical flow analysis and numerical structural analysis were respectively performed in the Fluent and Static Structural modules of the Ansys software. The aerodynamic analysis showed that flying at an altitude of 23 km with a speed of 1723 m/s, the scramjet with three compression ramps with deflection angles of 7,48°, 8,93° and 10,77° is capable of generating, at the entrance to the combustion chamber, speed corresponding to Mach number 1,709 and static temperature of 1071,255 K, demonstrating the possibility of burning hydrogen. At the trailing edge, the flow velocity is 1688,958 m/s without fuel burning and 1806,977 m/s with fuel burning, demonstrating that the scramjet is only capable of generating thrust with fuel ignition. For the numerical analysis of the flow, the unstructured mesh with triangular elements proved to be more suitable to capture the flow conditions after the oblique shock waves in the scramjet, considering atmospheric air as a calorically perfect gas and without viscous effects. In the aerodynamic analysis the numerical results showed good agreement with the analytical results. In the numerical structural analysis, the maximum von-Mises equivalent stress is 122,93 MPa and occurs at the leading edge of the fairing, close to contact with the side panel, due to the thickness of the wedge at the leading edge and the high pressures of the chamber of combustion. However, this value is lower than the yield stress of the materials used, so that strains and displacements in the structure occur in the elastic regime of the materials and are therefore recoverable.
11	WILLIAM HENRIQUE DE LIMA FIUZA Conception, Design and Structural Analysis of an Academic Shock Tube Advisor : PAULO GILBERTO DE PAULA TORO COMMITTEE MEMBERS : DOUGLAS DO NASCIMENTO SILVA GEORGE SANTOS MARINHO PAULO CELSO GRECO JÚNIOR PAULO GILBERTO DE PAULA TORO Data: Dec 22, 2022 Show Abstract The shock tube is an equipment used in laboratory studies on supersonic flows, providing data on the flight conditions in which the aerospace vehicles will find themselves. The Federal University of Rio Grande do Norte (UFRN) has stainless steel tubes – donated by the Institute of Advanced Studies (IEAv) – intended for the construction of the Institution's first shock tube. The objective of the research carried out was to make the construction of the equipment technically feasible. The correct sizing of the components is a fundamental part of the project, being essential to prevent accidents and control measurement errors during the tests, since it is a device subjected to high pressures. Structural modeling through software allows reducing material waste and operational risks during the construction of prototypes. Boundary conditions and applied loads must be rigorously selected, to provide a good level of confidence to the research results and, thus, constitute a guide for the execution of the academic project in a technical way. For this, the following were carried out and are presented here: calculations of the flow conditions; modeling and structural analysis of the high pressure (driver) and low pressure (driven) sections of the academic shock tube, considering the dimensions of the stainless steel tubes available at UFRN; in addition to determining the efforts to which the tubes will be submitted when the equipment becomes operational. Analytical (Lamé Equations) and numerical (Ansys Mechanical) results of circumferential, radial and von Mises stresses were compared by means of their percentage variations. Autodesk Inventor was also used for simulations and comparisons with Ansys Mechanical results. Both the driver and the driven were analyzed considering their ends closed by means of flanges and thus treated as pressure vessels. Ansys Mechanical and Autodesk Inventor software were used in the analysis, with discretization of the models by mesh generation and application of the Finite Element Method. A pressure of 70 atm (7.09 MPa) was applied to the inner surface of the high pressure section during calculations and computer simulation, while other pressures generated in the flow were calculated and applied to the low pressure section. All pressures were also multiplied by four to assess the impact of this change in stresses. Based on the results obtained for von Mises stresses, circumferential stresses, and radial stresses, it was found that, considering the properties of stainless steel AISI 304 and steel SAE 4140, the available tubes will withstand the workloads within the operating range to which they will be subjected without implying any risk of damage, in view of the first stage of the UFRN academic shock tube construction project.

2021

	Dissertations
1	ISAMARA DE MENDONÇA SILVA Investigating the teleconnection patterns associated with the rainy season and analyzing the homogeneity and the trend in extreme precipitation indices in the Northern of Northeast Brazil Advisor : DEUSDEDIT MONTEIRO MEDEIROS COMMITTEE MEMBERS : DAVID MENDES DEUSDEDIT MONTEIRO MEDEIROS MEIRY SAYURI SAKAMOTO Data: Feb 26, 2021 Show Abstract A first study used the hidden Markov model in this dissertation to describe the daily rainfall occurrence and intensity at four meteorological stations in the Metropolitan Region of Fortaleza in the Northern Northeast Brazil (NNB) and the teleconnection patterns that influence precipitation regime during the rainy season (February, March, April, and May) from 1975 to 2013. A model with four hidden states was associated with climatic conditions: very rainy (1), rainy (2), less rainy (3), and dry (4), satisfactorily agreeing with the interannual variability of the rainy season in this region. State 2 was the only one that showed a statistical trend, indicating a probable decrease in the occurrence of precipitation in the rainy season. It was also shown that the meteorology associated with states 2 and 4 is strongly related to the El Niño-South Oscillation and the North Atlantic tripole and is intrinsically conditioned by the large-scale atmospheric patterns of the Northern Hemisphere. All of these mechanisms modulated the displacement of the Intertropical Convergence Zone (ITCZ) southward (state 2) or northward (state 4), affecting the occurrence of precipitation in the NNB. State 1 was distinguished by the influence of the Atlantic Meridional Mode and the ITCZ displacement further south, while state 3 was identified by the absence of teleconnection patterns. A second study investigated the homogeneity and trend of eleven extreme precipitation indices from a daily data set of 84 rain gauges in the state of Ceará, located in the NNB, from 1974 to 2018, on the annual and seasonal time scales. The data were initially submitted to the gap-filling and quality control processes. Most precipitation series were classified as "useful," and dry day precipitation indices were more susceptible to breaks than rainy day variables for homogeneity. The significant break years in the series agreed well with the El Niño and La Niña events, suggesting a further investigation of this possible connection. The precipitation indices for rainy and dry days presented mostly decreasing and increasing trends, respectively, indicating a decline in the rainfall regime in Ceará, mainly in the central-eastern, northwestern, and southern regions, in the annual and rainy seasons. The LOWESS curve showed changes in almost all series during the 1980s and 1990s, coinciding with the homogeneity breaks and the years of severe droughts in the region. The correlation coefficients were strong and significant between all precipitation indices and the other variables, seeming to induce changes in total rainfall.
2	ARTUR CRISTIANO PAULINO PEREIRA Study of supersonic combustion in aerospace vehicle in atmospheric flight at Mach 5.8 and 20 km of altitude. Advisor : GEORGE SANTOS MARINHO COMMITTEE MEMBERS : DOUGLAS DO NASCIMENTO SILVA GEORGE SANTOS MARINHO JOÃO FELIPE DE ARAÚJO MARTOS PAULO GILBERTO DE PAULA TORO Data: Aug 26, 2021 Show Abstract In the present work, the thrust generation capacity of a scramjet integrated aerospace vehicle was evaluated from the combustion of hydrogen and atmospheric air at supersonic speed, for the flight of the scramjet vehicle at 20 km of altitude and speed of 1709.6 m/s, corresponding to Mach number of 5.79. A Theoretical-analytical method was used, considering the steady-state. The First Law of Thermodynamics, without and with reaction based on enthalpy of formation, was used to determine the properties. Correlations between the equivalence ratio with the mixture temperature, mixture speed, and exhausted gases temperature after combustion were obtained. The temperature and speed were also determined after the combustion gases expansion process. Mixing speed equal to 1152 m/s and exhaust gases temperature in the range of 2400 K to 2600 K was assumed, resulting in a fuel-air ratio in the range of 0.648 to 0.774 and mixing temperature of 875 K to 855 K. The temperature after the expansion varied from 865 K to 964 K, and the speed varied from 2425 m/s to 2532 m/s. A mean specific impulse equal to 4049.7 s was obtained, and positive non-installed thrust ranging from 760.8 N to 879.3 N.
3	PEDRO PAULO BATISTA DE ARAÚJO Supersonic combustion technology applied to the second stage of the nanoSats launch vehicle Advisor : PAULO GILBERTO DE PAULA TORO COMMITTEE MEMBERS : ROBERTO DA CUNHA FOLLADOR DOUGLAS DO NASCIMENTO SILVA PAULO CELSO GRECO JÚNIOR PAULO GILBERTO DE PAULA TORO SANDI ITAMAR SCHAFER DE SOUZA Data: Oct 15, 2021 Show Abstract Current rocket engines have a low specific thrust compared to the airbreathing propulsion technologies. Airbreathing supersonic combustion engines/vehicles are an alternative to improve the efficiency of access to space in a flight through the dense Earth’s atmosphere, below 60 km of geometric altitude. In this work, aerodynamic analysis of the conceptual model of supersonic combustion engine/vehicle (scramjet) was carried out to operate as a second-stage propulsion engine of a nanoSats launch vehicle. Two engineering approaches, analytical and computational numerical methodology, were used to perform the preliminary analysis of the proposed scramjet model, coupled to the third propulsion stage, at an altitude of 20 km with flight speed equivalent to Mach 5.8. Atmospheric air was considered a calorically perfect gas, and the viscous effects were neglect in a preliminary analysis. Supersonic combustion was modeled as heat adding to the supersonic flow without fuel injection. Then, numerical simulations were carried out considering the effects of the boundary layer development to verify the aerodynamic feasibility of the model. Optimization of the compression angles at the scramjet compression section was used to minimize the entropy generation and increase the vehicle’s compression efficiency, aiming to reach the temperature and Mach number at the combustion chamber entrance. The temperature required at the combustion chamber entrance is estimated to self-ignite the air-fuel mixture. Korkegi limit was evaluated through oblique shock waves in the compression section and in the heat addition process. Using the Korkegi limit, in the preliminary analytical design, as an indication of unstart due to the separation of the boundary layer caused by the adverse pressure gradient, we investigated to identify in numerical simulations considering the viscous effects whether the unstart phenomenon would occur. Numerical simulations were performed using commercial software, ANSYS Fluent, using the turbulence model known as transition SST. We also performed mesh convergence tests, numerical experiment validation on top of numerical data validated by HyShot flight data. Both meshes used in the validation and the analysis of the present work have equivalent levels of refinement in the direction of the wall, satisfying the condition of the turbulence model (𝑦+ < 1). The analytical calculations showed good quantitative and qualitative consistency with the numerical simulation results considering the same simplifications adopted in the analytical. An adaptation of the analytical method is proposed to take into account the effects of the interaction of the expansion fan with the oblique shock wave incident on the compression section of the scramjet. The results of the viscous simulations indicated that should be made improvements in the geometry due to the low temperature at the combustion chamber entrance, as well as reduced mass flow captured by the combustor, as a consequence of solution used to prevent unstart.
4	IAGO VINICIUS MACEDO SANTOS EVALUATION OF THE IMPACT OF DENSITY ON ROCKET FLIGHT Advisor : DOUGLAS DO NASCIMENTO SILVA COMMITTEE MEMBERS : CAMILA PACELLY BRANDÃO DE ARAÚJO DOUGLAS DO NASCIMENTO SILVA HEIDI KORZENOWSKI Data: Nov 19, 2021 Show Abstract In this present work, the implementation of the ordinary differential equations developed in the literature and which govern the movement of a rocket is presented, with the chosen vehicle being the VS-30 rocket. The code, which is developed in Matlab, is designed so that it is possible to compare the Earth's atmosphere as one composed of ideal gas, that is, an atmosphere in which the gases obey the Ideal Gas Law, and in another scenario , like being a type of Van der Waals. The final aim is to verify whether or not there is a large impact on the flight phenomenon as a whole, applying the Euler method to the solution of the equations already mentioned above.