This diploma thesis deals with the amateur radio astronomy. The work contains basic information from the field of radio astronomy and physics which deals with electromagnetic radiation. Also important information about our closest star, the Sun, are described. One of the main part of this thesis is a description of the radio receiver and antenna used to receive radio signal from the Sun. The following parts then described the production of Radio JOVE receiver and the measurements on the receiver.

O sol é a fonte de energia mais importante para todos os seres vivos no planeta Terra. Os sistemas concentrados de energia solar e fotovoltaica apresentaram avanços importantes na eficiência da conversão da irradiação solar em energia elétrica. A redução dos custos do equipamento necessário, combinada com um maior acesso ao conhecimento com a popularização da internet, permitiu que esta tecnologia se encontrasse em vários setores da sociedade. Neste estudo, analisou-se a eficiência energética de um painel solar com sistema de rastreamento de controle em circuito fechado baseado em fotoresistores. Este painel solar foi projetado e montado com tecnologia DIY em comparação com um painel de ângulo fixo. O sistema foi analisado em três condições atmosféricas diferentes: sol, parcialmente nublado e totalmente nublado. Os dados de corrente elétrica produzidos pelos dois sistemas e a carga consumida pelo painel do rastreador foram gravados automaticamente usando um sistema de coleta de dados para cada painel fotovoltaico. O sistema com rastreador mostrou uma produção de energia de 24,52% maior do que o painel fixo no período de maior radiação solar. Observou-se que a produção de energia do painel com sistema de rastreamento é maior durante períodos de ângulo de elevação inferior em relação ao horizonte. No entanto, a análise de eficiência energética do sistema de rastreamento apresentou uma comparação de geração de energia elétrica negativa em relação ao painel de ângulo fixo, e o painel com rastreador apresentou um custo elevado de 216,60% em relação ao painel em ângulo fixo. Portanto, não compensa o uso da tecnologia DIY nas condições testadas. / The sun is the most important source of energy for all living beings on planet Earth. Concentrated solar and photovoltaic systems have presented important advances in the efficiency of the conversion of solar irradiation to electric energy. The reduction in the costs of the necessary equipment, combined with greater access to knowledge with the popularization of the internet, has allowed this technology to be present in several sectors of society. In this study the energy efficiency of a solar panel with closed loop control tracker system based on photoresistors was analyzed. This solar panel was designed and assembled with DIY technology compared to a fixed-angle panel. The system was analyzed in three different atmospheric conditions: sunny, partly cloudy and totally cloudy. The electrical current data produced by the two systems and the load consumed by the tracker panel were automatically recorded using a data collection system for each photovoltaic panel. The system with tracker showed energy production of 24.52% higher than the fixed panel in the period of higher solar radiation. It was observed that the energy production of the panel with tracker system is higher during periods of lower elevation angle with respect to the horizon. However, the energy efficiency analysis of the tracking system presented a compared to of negative electric power generation in relation to the fixed-angle panel, and the panel with tracker presented a high cost of 216,60% in relation to the panel in fixed form. Therefore, it does not compensate for the use of DIY technology in the tested conditions.

Magnetic field permeates the solar atmosphere and plays a crucial role in the dynamics, energetics and structures observed. In particular, magnetic flux tubes provide the structure for coronal loops that extend from the solar surface into the corona. In this thesis, we present 3D numerical simulations examining the heating produced by reconnection between flux tubes driven by rotational footpoint motions. The basic model consists of two, initially aligned, flux tubes that are forced to interact by rotational driving velocities on the flux concentrations on the boundaries. A single, twisted current layer is created in the centre of the domain and strong, localised heating is produced. We extend this model by altering the number, distribution and strength of the sources, while maintaining the same total magnetic flux on the boundaries. The dynamical evolution and the resultant magnitude, distribution and timing of the heating events are examined for the different flux distributions. In all cases, the magnetic field is stressed by the boundary motions and a current grows within the domain. A comparison of cases with two and four sources shows that there are more locations of current concentrations, but with reduced maximum current density values, for the four source case. This produces weaker reconnection and less efficient heating. In addition, for the case with two sources, we also consider the effect of splitting up one of the sources into many smaller flux fragments. The evolution and heating are shown to be very similar to the two source case. The impact of increasing the strength of the background field between the flux tubes is also examined and we find that it delays and increases the strength of the heating, although by how much depends on the distribution of the flux sources.

No description available.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Meteorology, 1970. / Lacking leaf 149. / Bibliography: leaves 163-169. / by Edward Harold Blish. / M.S.

Vitamin D is important to the health of college students. The objective of our study was to measure sun exposure, skin pigmentation, vitamin D intake, and serum 25-hydroxyvitamin D (25[OH]D) in a subset of participants from The Following the Longitudinal Aspects of Student Health (FLASH) Study to determine the best predictors of 25(OH)D status. Participants were college-aged freshman who had their blood drawn in spring (Visit 1) and fall 2010 (Visit 2) at California Polytechnic State University (Cal Poly), San Luis Obispo, CA. (35.3°N). Vitamin D intake was measured using a 28-day food frequency recall questionnaire (specific to vitamin D foods and supplements) while questions specific to the frequency of milk and fish intake were accessed from the FLASH questionnaire. Sun exposure was measured using a 28-day recall questionnaire (time in sun and sun exposure index [SEI]) and questions (frequency of weekday/ weekend exposure) from the FLASH questionnaire. Skin pigmentation was measured using a reflectance spectrophotometer. Serum 25(OH)D was measured at a local pathology lab as measured by an IDS-iSYS. Means (SD) were as follows (n= 40): reflectance of the forehead was 61 (3.5) L* (Lightness) for Visit 1 and 61 (4.3) L* for Visit 2. Vitamin D intake was 308 (234) IU for Visit 1 and 316 (257) IU for Visit 2. Time outside was 81 (44) mins for Visit 1 and 76 (39) mins for Visit 2. Serum 25(OH)D was 85 (24) nmol/L for Visit 1 and 113 (28) nmol/L in Visit 2 which was significantly higher (p < 0.0001). The SEI was 53 (38) body surface area (BSA) exposed (m2) x mins for Visit 1 and 55 (34) m2 x mins Visit 2. Although 90% of participants in Visit 1 and 88% in Visit 2 were below the RDA guidelines for vitamin D intake (600 IU/day), 5% of participants in Visit 1 and none in Visit 2 had serum 25(OH)D serum levels < 50 nmol/L (the recommended level of sufficiency for bone health), demonstrating the importance of sun exposure to vitamin D status in these college students. To determine the strongest predictors of status we used regression analysis to predict serum 25(OH)D with skin reflectance, vitamin D intake, and sun exposure. We found that weekend sun exposure, fish intake, and forehead skin reflectance were the strongest predictors of serum 25(OH)D (R2= 0.50, p= 0.0010) demonstrating that simple questionnaires can help to predict serum 25(OH)D status.

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This thesis posits the creation of a lunar settlement, examining the practical and theoretical challenges of urban design in a space environment. Analysis of the lunar environment aided by data and imagery from the Lunar Reconnaissance Orbiter allows the project to narrow focus on site selection while simultaneously capturing the bizarre and beautiful landscape. Intensive site study becomes the framework of a uniquely tailored, imaginative design emphasizing an urban fabric that is sensitive to astrological presences through passive and reactive design. / Master of Science / Whether it be through accident, conquest, or expedition, humanity has long held an innate desire to root itself in new environments that challenge us. The sky has proven to be no limit, the 20th century has shown that the exploration and colonization of space is inevitable. The question is where will we begin the first colony in space and what form will it take? This thesis posits the creation of a lunar settlement, examining the practical and theoretical challenges of urban design in a space environment. Site selection is crucial with the birth of any new city or civilization. Much like settlers of the past, a thorough understanding of constraints and strategic positioning is necessary to ensure the growth and survival of a colony. The accumulative site knowledge presented with this thesis is the framework of a uniquely tailored design to sustain long-term inhabitance on the moon. While this project can make no bold claims to predict the intentions of future colonists, it does serve to create an imaginative urban form to begin this journey, derived from grounded research and intensive site study. This thesis adds new perspectives beyond conventional engineered plans, to explore the potential of an immersive, reactive urban fabric with sensitivity to astrological presences. Urban design recommendations are made to enhance day to day livability in space, offer a sense of time and place, foster meaningful interaction among colonists, and consider growth beyond the initial settlement. While such a colony will undoubtedly serve as the staging area for the next steps in space exploration, it foremost will be a testament to what we as a people choose to collectively bring with us to the moon.

Time is an ever-present entity that is an incredibly complex yet constant force in the life of each and every one of us. Since earliest history, humanity has attempted to recognize and use the evaluation of time to an advantage, eventually developing time into measurable commodity with determinable value. Beyond the obvious respect of time measurement, the larger concept of 'time' and its applications is of value to nearly every discipline. In the case of architecture, we have the ability to manipulate and use time to serve a purpose, whether that be creating a sundial to celebrate time passing or creating a black box to shield us from time's presence. In most cases though, time is merely a variable to work with to achieve a higher goal. This thesis looks to reverse this concept and use time and its varying manifestations as the main parameter to drive and develop architecture. In this case, the architecture will take the form of a school; a perfect example of a program in need of the recognition of time not only for its fluctuating yet ordered schedules and calendars, but also for the conservation and expedient use of this valuable commodity. Most importantly though, a school provides a significant opportunity to showcase the educational capability that results from the experience in, and the observance of, time itself. This thesis will produce a design for a Pre-K-through-8th grade school to be located on the site of the existing Jefferson-Houston School in Alexandria, VA. / Master of Architecture

Increasing observational evidence of wave modes brings us to a closer understanding of the solar corona. Coronal seismology allows us to combine wave observations and theory to determine otherwise unknown parameters. The period ratio, P₁/2P₂, between the period P₁ of the fundamental mode and the period P₂ of its first overtone is one such tool of coronal seismology and its departure from unity provides information about the structure of the corona. In this thesis we consider the period ratio P₁/2P₂ of coronal loops from a theoretical standpoint. Previous theory and observations indicate that the period ratio is likely to be less than unity for oscillations of coronal loops. We consider the role of damping and density structuring on the period ratio. In Chapter 2 we consider analytically the one-dimensional wave equation with the inclusion of a generic damping term for both uniform and non-uniform media. Results suggest that the period ratio is dominated by longitudinal structuring rather than damping. In Chapter 3 we consider analytically the effects of thermal conduction and compressive viscosity on the period ratio for a longitudinally propagating sound wave. We find that damping by either thermal conduction or compressive viscosity typically has a small effect on the period ratio. For coronal values of thermal conduction the effect on the period ratio is negligible. For compressive viscosity the effect on the period ratio may become important for some short hot loops. In Chapter 4 we extend the analysis of Chapter 3 to include radiative cooling and find that it too has a negligible effect on the period ratio for typical coronal values. As an extension to the investigation, damping rates are considered for thermal conduction, compressive viscosity and radiative cooling. The damping time is found to be optimal for each mechanism in a different temperature range, namely below 1 MK for radiative cooling, 2 − 6 MK for thermal conduction and above 6 MK for compressive viscosity. In Chapter 5 we consider analytically the period ratio for the fast kink, sausage and n = N modes of a magnetic slab, discussing both an Epstein density profile and a simple step function profile. We find that transverse density structuring in the form of an Epstein profile or a step function profile may contribute to the shift of the period ratio for long thin slab-like structures. The similarity in the behaviour of the period ratio for both profiles means either can be used as a robust model. We consider also other profiles numerically for the kink mode, which are found to be either slab-like or Epstein-like suggesting again that it is not necessary to distinguish the nature of the density profile when considering the period ratio.