Experimental testing of attitude determination systems still plays an important role, despite increasing use of simulations. Testing provides a means to numerically quantify system performance, give confidence in the models and methods, and also discover and compensate for unexpected behaviours and interactions with the attitude determination system. The usefulness of the test results is dependent on an understanding of the uncertainties that contribute to the attitude error. With this understanding, the significance of the results can be assessed, and efforts to reduce attitude errors can be directed appropriately. The work of this thesis is to gain a quantitative understanding of the uncertainties that impact the attitude error of low cost spinning spacecraft using COTS camera (as Sun sensor) and MEMS magnetometer. The sensors were calibrated and the uncertainties in these calibrations were quantified, then propagated through the Triad method to uncertainties in the attitude. It was found that most systematic errors were reduced to negligible levels, except those due to timing latencies. Attitude errors achieved in the laboratory with the experimental setup were around 0.14 degrees (3σ) using either the Triad, q-method or Extended Kalman Filter with a gyro for dynamic model replacement. The errors in laboratory were dominated by magnetometer noise. Furthermore, correlated systematic errors had the effect of reducing the attitude error calculated in the laboratory. For an equivalent Sun-mag geometry in orbit, simulation showed that total attitude error would be of the order of 0.77 degrees (3σ). An uncertainty contribution analysis revealed this error was dominated by uncertainties in the inertial magnetic field model. Uncertainties in knowledge of the inertial Sun model, sensor calibration, sensor alignment and sensor noise were shown to be insignificant in comparison.

Vibration monitoring is widely used to determine the condition of various mechanical systems. Traditionally a transducer is attached to the structure under investigation and the vibration signal recorded. This signal is then processed and the required information extracted from the signal. With epicyclic gearboxes this traditional approach is not advisable. This is in part due to the fact that the planet gears rotate internally on a planet carrier. Special techniques are therefore required to extract a viable data signal from the measured vibration signal. These techniques require an additional post-processing step in which a compiled data signal is extracted from the measured data signal. This work investigates the possibility of mounting transducers internally on the rotating planet carrier. Mounting transducers at this location removes the relative motion seen in traditional measurement techniques. An epicyclic gearbox is modified to facilitate the internal mounting of the accelerometers. A number of implementation problems are highlighted and solutions to these problems are discussed. A large portion of the work is dedicated to implementing and qualifying the epicyclic time synchronous averaging technique which is traditionally used to evaluate epicyclic gearboxes. As this technique forms the basis to evaluate the data obtained from internal measurements, it is of fundamental importance that the technique is implemented correctly. It is shown that vibration data can be reliably measured internally, by means of accelerometers mounted on the planet carrier. The internally measured data is compared to data obtained by traditional techniques and shown to be equally adept in detecting deterioration of a planet gear tooth. Simple condition indicators were used to compare the vibration data of the two techniques. It was seen that the data obtained from the internally mounted accelerometers was equally, and in certain cases, slightly more sensitive to planet gear damage. This implies that the technique can be used successfully to evaluate epicyclic gearbox damage. There are a number of practical implementation problems that will limit the use of this technique. As the technology becomes available to transmit measured vibration signals wirelessly, the application of the internal measurement technique will become more viable. A preliminary investigation was also launched into the relationship between a planetary gearbox with a single planet gear and one with multiple planet gears. It is illustrated that vibration data, measured from a gearbox containing a single planet gear, shows an increased sensitivity to planet gear damage. Although a special test rig might be required, the increased sensitivity to damage can provide a method to test planet gears in critical applications such as aircraft gearboxes. Copyright / Dissertation (MEng)--University of Pretoria, 2010. / Mechanical and Aeronautical Engineering / unrestricted

We investigate the physics of charged-particle acceleration at spherical shocks moving into a uniform plasma containing a turbulent magnetic field with a uniform mean. This has applications to particle acceleration at astrophysical shocks, most notably, to supernovae blast waves. We numerically integrate the equations of motion of a large number of test protons moving under the influence of electric and magnetic fields determined from a kinematically defined plasma flow associated with a radially propagating blast wave. Distribution functions are determined from the positions and velocities of the protons. The unshocked plasma contains a magnetic field with a uniform mean and an irregular component having a Kolmogorov-like power spectrum. The field inside the blast wave is determined from Maxwell's equations. The angle between the average magnetic field and unit normal to the shock varies with position along its surface. It is quasi-perpendicular to the unit normal near the sphere's equator, and quasi-parallel to it near the poles. We find that the highest intensities of particles, accelerated by the shock, are at the poles of the blast wave. The particles "collect" at the poles as they approximately adhere to magnetic field lines that move poleward from their initial encounter with the shock at the equator, as the shock expands. The field lines at the poles have been connected to the shock the longest. We also find that the highest-energy protons are initially accelerated near the equator or near the quasi-perpendicular portion of the shock, where the acceleration is more rapid.

No description available.

My diploma is abou segmentation and market research of sun lotions.

The purpose of this exploratory study was to identify the key predictors of prostate cancer; such study may lead to the development of appropriate interventions and prevention. Previous epidemiological studies have found these following factors to be key predictors for being diagnosed with hormone-associated carcinoma such as prostate cancer: age, ethnicity, physical activity, family history, diet, sleep amount, marital status, and having another form of carcinoma. Many studies have included results only for men over the age of 65, however, prostate cancer is claiming the lives of many African American, Hispanic and White American men over the age of 35, and younger men are more likely to battle it if they are genetically predisposed. The sample population (N =21,646) was selected because men aged 35 or over have the highest prevalence of prostate cancer. Of this sample, 619 reported having prostate cancer, and 1,401 reported having some other type of cancer. This study employs a logistic regression model using SAS® and utilizes the National Health Interview Survey data set and a multivariate analysis of the years 2006, 2007, and 2008. To improve the quality of future research the methods need modification, the subpopulation being studied should be larger, and the studies should be longitudinal. This particular study found the aforementioned factors to be critical in predicting prostate cancer. Maximum sun exposure was found to be also related to having prostate cancer. Key predictors for prostate cancer diagnosis are age, ethnicity, having some other cancer and maximum sun exposure, and education. Though previous studies have found physical activity, sleep amount, and occupation to be beneficial in reducing the risk for prostate cancer, it was not confirmed in this particular study.

Orientador: Anderson Campos Fauth / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-08-28T23:49:34Z (GMT). No. of bitstreams: 1 Vasconcelos_DeboraNunesBarrosde_M.pdf: 12164737 bytes, checksum: b673ae31e92a75895beeb827173604e6 (MD5) Previous issue date: 2015 / Resumo: Desde os lançamentos dos satélites científicos, o estudo do Sol e a influência dos seus eventos nà Terra tem sido aprofundado constantemente devido as possíveis consequências no clima da Terra e a danos nos sistemas de comunicações. Entretanto, os detectores embarcados nos satélites tem limitações que não permitem medições de energias das partículas energéticas solares superiores a algumas centenas de MeV. Neste trabalho é descrita a construção, instalação e montagem do telescópio de múons, em Campinas-SP, denominado Muonca, para detecção dessas partículas da radiação cósmica secundária, originadas na atmosfera principalmente por interações de prótons. O principal objetivo deste experimento é a detecção de eventos solares transientes numa faixa de energia superior àquela operada pelos satélites. O fato do telescópio estár dentro, e próximo da região central, da Anomalia Magnética do Atlântico Sul, permite uma melhor detecção de partículas carregadas provenientes do espaço externo, pois o fluxo de partículas nessa região é maior. Foram construídos quatro detectores de partículas utilizando placas de cintilador plástico e tubos fotomultiplicadores que em conjunto formam os telescópios de múons do Muonca. Esses telescópios detectam múons verticais e inclinados a 45 graus vindos da direção Leste e da direção Oeste. Após a montagem do telescópio, a sua caracterização de eficiência de contagem foi realizada o seu valor é de (96,8 ± 0,4)%. O coeficiente barométrico foi medido, sendo seu valor igual a ? =(0,22 ± 0,04)%/mbar, condizente com outros experimentos de múons. Dados de 01 de abril de 2014 até 31 de janeiro de 2015 foram analisados e o mês de setembro de 2014 foi estudado detalhadamente. Neste mês foram um evento de decréscimo de Forbush da ordem de 1%. Os resultados do Muonca foram comparados com os resultados do monitor de nêutrons McMurdo o qual detectou o mesmo evento. Uma análise utilizando os resultados do satélite GOES15 da NASA mostrou que este Forbush foi originada por três CMEs, sendo que duas dessas ejeções foram associadas a flares de classe M4.6 e X1.6. O experimento Muonca foi construído com sucesso e está operando continuamente, permitindo o estudo da física solar através da detecção de múons no solo terrestre / Abstract: Since the launch of scientific satellites to study the Sun and the influence of their events on Earth has been constantly deepened because of the possible consequences in Earth's climate and the damage to the communications systems. However embedded in the satellite detectors have limitations relating to measurements of energies of the solar energetic particles larger than a few hundred MeV. This work describes the construction, installation and assembling of the muon telescope in Campinas-SP, called Muonca, to detect these particles of secondary cosmic radiation, originated in the atmosphere mainly by proton interactions. The main objective of this experiment is the detection of solar transient events in a higher energy that operated by satellites. The fact that the telescope be within, and near the central region of the South Atlantic Magnetic Anomaly, allows better detection of charged particles coming from outer space because the flux of particles in this region is higher. Four particle detectors, using plastic scintillator and photomultiplier tubes, which together form the muon telescopes Muonca were constructed. These telescopes detect vertical and inclined at 45 degrees muons coming from the East and West direction. After mounting the telescope, its counting efficiency was measured and its value is (96,8 ± 0,4)%. The barometric coefficient was measured, and its value of ? =(0,22 ± 0,04)%/mbar was obtained, beeing consistent with other muon experiments. Data from April 1st 2014 to January 31th 2015 were analyzed and September 2014 has been studied in detail. In this month the Muonca detected a Forbush decrease of the order of 1%. The results of Muonca were compared with the results of McMurdo neutron monitor which detected the same event. An analysis using the results of GOES15 NASA satellite showed that this Forbush originated three CMEs, and two of those ejections were associated with flares of M4.6 and x1.6 class. The Muonca experiment was successfull constructed and is operating continuously, allowing the study of solar physics through the muon detection in terrestrial soil / Mestrado / Física / Mestra em Física / 2012/1139485 / 2011/50193-4 / CAPES / FAPESP

The diploma thesis is focused on the evaluation of a photovoltaic power plant in the company premises. The first chapters briefly discuss the theory of electricity generation using photovoltaic panels. It describes the principle of operation of photovoltaic panels, history, production, etc. In the practical part of the thesis we focus on the evaluation of the company's photovoltaic power plant when comparing real data with simulations.

京都大学 / 新制・課程博士 / 博士(情報学) / 甲第23328号 / 情博第764号 / 新制||情||130(附属図書館) / 京都大学大学院情報学研究科通信情報システム専攻 / (主査)教授 原田 博司, 教授 守倉 正博, 教授 大木 英司 / 学位規則第4条第1項該当 / Doctor of Informatics / Kyoto University / DFAM

With over 600 articles about terrestrial invertebrates in Svalbard we still lack basic knowledge about pollinator-plant interactions in this part of the high-Arctic. It has never before been investigated how the activity of pollinators varies over a 24-hour timeframe in the high Arctic. Insects in the lower Arctic have been shown to have their peak foraging around noon but as Svalbard experiences midnight sun during the whole summer season pollinators could potentially forage any time during the 24-hour day. In this study pictures were taken every minute over cushions of Silene acaulis, capturing visiting pollinators during 5 days around the beginning of July 2019. Pollinators showed no higher abundance around noon. Instead, no significant difference in the abundance of pollinators was found between the hours of the 24-hour timeframe. No significant connection between the abundance of insects and temperature was found as well as no significant connection between the abundance of insects and wind. The results in this study can contribute to fill the knowledge gap of pollinator-plant interactions in Svalbard and show the need for more research about pollinators temporal dynamics in the high-Arctic.