The demand for electricity is increasing daily due to technological advancement, and ?luxurious lifestyles. Increasing utilization of electricity means the depletion of fossil fuel ?reserves. Thus, governments around the world are seeking alternative and sustainable ?sources of energy such as the solar powered system. The main purpose of this research is ?to develop a knowledge base on residential electric generation from the grid and solar ?energy. This paper examined the economic feasibility of using grid-tied residential ?photovoltaic (GRPV) system in Saudi Arabia with the HOMER software. Models ?forecasting the price of oil barrels through artificial neural networks (ANN) were also ?employed in the analysis. The study shows that an oil-rich country like Saudi Arabia has ?potential to utilize the GRPV system as an alternative source of energy. / This paper examined the economic feasibility of using grid-tied residential photovoltaic ??(GRPV) system in Saudi Arabia with the HOMER software. Models forecasting the ?price of oil barrels through artificial neural networks (ANN) were also employed in the ?analysis. The study shows that an oil-rich country like Saudi Arabia has potential to ?utilize the GRPV system as an alternative source of energy. This study provides a ?discussion of the potential for applying solar-powered and an assessment of the ?performance of existing systems based on collecting output data.?

19 Dec 2004. / Published through the Information Bridge: DOE Scientific and Technical Information. "IS-T 2626" Daniel Bryan Gazda. 12/19/2004. Report is also available in paper and microfiche from NTIS.

Orientador: Teófilo Miguel de Souza / Resumo: Esta Tese de Doutorado apresentou o estudo dos problemas de tensão originados no ponto comum de conexão de uma rede experimental para fornecer até 1.000 kWh/mês de energia solar com a rede de baixa tensão da Universidade de Ibagué, na Colômbia. Inicialmente foi feita uma introdução, onde destacou-se a importância da geração distribuída, os problemas gerados e os objetivos propostos. Em seguida, foi realizado o estudo da qualidade da energia na rede de baixa tensão, conforme as normas NTC 5001. Foi dimensionada, montada e colocada em operação uma rede experimental, utilizando a metodologia proposta nesta Tese, composta de 30 painéis solares de 260 W marca IBC solar, um inversor marca Fronius de 7,6 kW e um contador bidirecional ligados diretamente à rede através com fio de seção transversal de 6,0 mm2. A energia máxima produzida pela rede experimental foi de 850 kWh/mês, equivalente a 72,65% do total da capacidade instalada. Os painéis solares apresentaram uma eficiência média de 15,7%, a eficiência do inversor foi obtida na faixa de 75 a 94% e o desempenho global, PR, entre 0,83 e 1,30. Depois de avaliar a rede experimental seguiu-se com a análise da qualidade da energia no ponto comum de ligação registrando, em relação às perturbações de longa duração, um aumento de 2%; o desequilíbrio da tensão diminuiu 3,5%, as harmônicas de tensão aumentaram 7% na linha U1, 0,8% na linha U2 e 3% na linha U3. Em relação à corrente harmônica foi evidenciado um incremento de 22% na linha U1.... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor

The field of noble gas mass spectrometry is a rapidly developing one. There is a sustained requirement for continuous development of instrumentation in order to allow researchers to answer critical questions facing their respective fields. Within planetary science, the question of whether our solar system is 'typical', has been a driving force behind many lines of research. This project sought to build upon the strong instrumental base of the Isotope Geochemistry and Cosmochemistry group of the University of Manchester, in order to develop the Resonance Ionisation Mass Spectrometer for Krypton Isotopes. From that basis, it then sought to develop techniques and protocols for the analysis of extra-terrestrial samples, particularly those of very low mass. The thesis is broken down into three studies. The first involved the development of the mechanisms used to fill the Xe-Ar four-wave mixing cell. This section covers the development, implementation, and characterisation of the newly installed mass flow controllers. The additional control over the mixing ratio granted allowed an eightfold increase to the sensitivity of the instrument. The reproducibility of the gas ratio is consistently shown throughout, and has ultimately reduced the tuning time of the instrument from a number of weeks to a day. The second section details the required procedures involved in data reduction, and the development of protocols and software for the RIMSKI instrument. A range of approaches are assessed, including a novel approach to cosmic ray exposure age calculations. The methods are discussed and implemented on extra-terrestrial samples, the Stannern eucrite and the Bereba eucrite. Finally, the analytical limits of the RIMSKI instrument are expanded via the measurement of the krypton systems of individual calcium-aluminium-rich inclusions. It is observed that Allende CAIs show a trapped component, Br-derived Kr, as well as an anomalous 'heavy Kr' component (one that is enriched in 86Kr). It is additionally noted that there is a lack of cosmogenic krypton to be found in all but one of the measured inclusions. The implications of these findings are discussed.

Lightning is an important electrical phenomenon, known to exist in several Solar System planets. Amongst others, it carries information on convection and cloud formation, and may be important for pre-biotic chemistry. Exoplanets and brown dwarfs have been shown to host environments appropriate for the initiation of lightning discharges. In this PhD project, I aim to determine if lightning on exoplanets and brown dwarfs can be more energetic than it is known from Solar System planets, what are the most promising signatures to look for, and if these "exo-lightning" signatures can be detected from Earth. This thesis focuses on three major topics. First I discuss a lightning climatology study of Earth, Jupiter, Saturn, and Venus. I apply the obtained lightning statistics to extrasolar planets in order to give a first estimate on lightning occurrence on exoplanets and brown dwarfs. Next, I introduce a short study of potential lightning activity on the exoplanet HAT-P-11b, based on previous radio observations. Related to this, I discuss a first estimate of observability of lightning from close brown dwarfs, with the optical Danish Telescope. The final part of my project focuses on a lightning radio model, which is applied to study the energy and radio power released from lightning discharges in hot giant gas planetary and brown dwarf atmospheres. The released energy determines the observability of signatures, and the effect lightning has on the local atmosphere of the object. This work combines knowledge obtained from planetary and earth sciences and uses that to learn more about extrasolar systems. My main results show that lightning on exoplanets may be more energetic than in the Solar System, supporting the possibility of future observations and detection of lightning activity on an extrasolar body. My work provides the base for future radio, optical, and infrared search for "exo-lightning".

Submitted by Agustin Valverde Granja (agustin.valverde@unibague.edu.co) on 2017-06-28T14:11:40Z No. of bitstreams: 1 Tesis Agustin Valverde Granja.pdf: 5383238 bytes, checksum: fc4a71b7db5d1316ec5199f86e031e0f (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-06-28T20:34:40Z (GMT) No. of bitstreams: 1 valverdegranja_a_dr_guara.pdf: 5383238 bytes, checksum: fc4a71b7db5d1316ec5199f86e031e0f (MD5) / Made available in DSpace on 2017-06-28T20:34:41Z (GMT). No. of bitstreams: 1 valverdegranja_a_dr_guara.pdf: 5383238 bytes, checksum: fc4a71b7db5d1316ec5199f86e031e0f (MD5) Previous issue date: 2017-06-23 / Esta Tese de Doutorado apresentou o estudo dos problemas de tensão originados no ponto comum de conexão de uma rede experimental para fornecer até 1.000 kWh/mês de energia solar com a rede de baixa tensão da Universidade de Ibagué, na Colômbia. Inicialmente foi feita uma introdução, onde destacou-se a importância da geração distribuída, os problemas gerados e os objetivos propostos. Em seguida, foi realizado o estudo da qualidade da energia na rede de baixa tensão, conforme as normas NTC 5001. Foi dimensionada, montada e colocada em operação uma rede experimental, utilizando a metodologia proposta nesta Tese, composta de 30 painéis solares de 260 W marca IBC solar, um inversor marca Fronius de 7,6 kW e um contador bidirecional ligados diretamente à rede através com fio de seção transversal de 6,0 mm2. A energia máxima produzida pela rede experimental foi de 850 kWh/mês, equivalente a 72,65% do total da capacidade instalada. Os painéis solares apresentaram uma eficiência média de 15,7%, a eficiência do inversor foi obtida na faixa de 75 a 94% e o desempenho global, PR, entre 0,83 e 1,30. Depois de avaliar a rede experimental seguiu-se com a análise da qualidade da energia no ponto comum de ligação registrando, em relação às perturbações de longa duração, um aumento de 2%; o desequilíbrio da tensão diminuiu 3,5%, as harmônicas de tensão aumentaram 7% na linha U1, 0,8% na linha U2 e 3% na linha U3. Em relação à corrente harmônica foi evidenciado um incremento de 22% na linha U1. Nos valores das cintilações de curto e longo prazo. Para os picos e interrupções de longa duração não foram encontrados diferenças significativas. Nas perturbações rápidas a potência ativa e reativa total no período do recesso aumentaram 58% e 42% respectivamente. A análise termográfica permitiu estabelecer um aumento da temperatura no ponto comum de ligação à rede de 7,5%. A temperatura superficial do painél foi calculada a partir do modelo matemático proposto neste trabalho para a cidade de Ibagué. O modelo foi resultado de uma análise estatística com o software Minitab e utilizou os dados da variação da radiação solar e da temperatura ambiente. Quando a temperatura do painel foi maior que a temperatura ambiente, a porcentagem de erro do modelo foi de 14,09%. O análise econômica permitiu estabelecer os custos de investimento por kWp instalado na rede experimental com ovalor de 2100 USD/kWp. O valor presente líquido (VPL) começou a apresemtar valores positivos a partir de 6,3 anos e a taxa interna de retorno (TIR) calculada para este projeto foi de 17,8%. Espera-se que as experiências no projeto possam servir de referência na aplicação da lei 1715 do governo Colombiano para o aproveitamento da energia solar. / This doctoral thesis presented the study of voltage problems originating from the common point of connection of an experimental network to provide up to 1,000 kWh / month of solar energy with the low voltage network of the University of Ibague in Colombia. Initially an introduction was made, highlighting the importance of distributed generation, the problems generated and the proposed objectives. Next, the study of the quality of the energy in the low voltage network was carried out, according to the norms NTC 5001. An experimental network was dimensioned, assembled and put into operation using the methodology proposed in this thesis, composed of 30 solar panels of 260 W brand IBC solar, a Fronius brand inverter of 7.6 kW and a bidirectional counter connected directly to the network through thread of cross-section of 6.0 mm2. The maximum energy produced by the experimental network was 850 kWh / month, equivalent to 72.65% of the total installed capacity. The solar panels had an average efficiency of 15.7%, the efficiency of the inverter was obtained in the range of 75 to 94% and the overall performance, PR, between 0.83 and 1.30. After evaluating the experimental network, it was followed by the analysis of the quality of the energy at the common point of connection, in relation to long-term disturbances, an increase of 2%; the voltage unbalance decreased by 3.5%, voltage harmonics increased by 7% in line U1, 0.8% in line U2 and 3% in line U3. In relation to the harmonic current, an increase of 22% in line U1 was evidenced. In the values of short and long term scintillations. For peaks and long-term interruptions no significant differences were found. In the fast perturbations the total active and reactive power in the period of the recess increased 58% and 42% respectively. The thermal analysis allowed to establish an increase in temperature at the common point of connection to the network of 7.5%. The surface temperature of the panel was calculated from the mathematical model proposed in this work for the city of Ibagué. The model was the result of a statistical analysis with Minitab software and used the data of solar radiation variation and ambient temperature. When the panel temperature was higher than the ambient temperature, the model error percentage was 14.09%. The economic analysis allowed us to establish the investment costs per kWp installed in the experimental network with a value of 2100 USD / kWp. The net present value (NPV) began to show positive values from 6.3 years and the internal rate of return (TIR) calculated for this project was 17.8%. It is hoped that the experiences in the project can serve as reference in the application of law 1715 of the Colombian government for the exploitation of solar energy.

Submitted by Erika Demachki (erikademachki@gmail.com) on 2018-06-29T17:37:19Z No. of bitstreams: 2 Dissertação - Elizandra Freitas Moraes Borges - 2018.pdf: 4498906 bytes, checksum: a63f9e990f16ee36ffc984d2f0cac3d6 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-07-03T14:51:28Z (GMT) No. of bitstreams: 2 Dissertação - Elizandra Freitas Moraes Borges - 2018.pdf: 4498906 bytes, checksum: a63f9e990f16ee36ffc984d2f0cac3d6 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-07-03T14:51:28Z (GMT). No. of bitstreams: 2 Dissertação - Elizandra Freitas Moraes Borges - 2018.pdf: 4498906 bytes, checksum: a63f9e990f16ee36ffc984d2f0cac3d6 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-05-03 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The present research in Astronomy Education intended to understand how students' mental models of the Solar System and Stars can be modified by reading two children's books written by astronomy writers in order to minimize conceptual and alternative conceptions. Participated in the research 26 students of the 7th grade of Junior School by the Municipal Secretariat of Education of Goiânia. The study was based on a qualitative approach based on Johnson-Laird's Mental Models (1983) and Piaget's (2012) Genetic Epistemology. To do so, the following sources of data were taken: pictorial, through drawings made by students before and after reading literary books; oral expressions in conversation; and writing, with descriptions of the drawings after reading. To analyze the data, a framework was created for each theme, explaining the Conceptual Model presented by the authors. Starting from the reference of this model, the analysis of the models brought by the students before the reading was verified, that was verified if there was a change of these mental models in a moment post-reading. It was verified that the mental models after the reading of the children's literary books were modified, however, these changes were not significant to eliminate previous conceptions in students' minds. / A presente pesquisa em Educação em Astronomia pretendeu entender como os modelos mentais dos estudantes sobre o Sistema Solar e Estrelas podem ser modificados a partir da leitura de dois livros infantis escritos por autores com formação na área de Astronomia, a fim de se minimizarem os erros conceituais e as concepções alternativas. Participaram da pesquisa 26 estudantes do 7º ano do Ensino Fundamental II de uma escola conveniada com a Secretaria Municipal de Educação de Goiânia. O estudo apoiou-se numa abordagem qualitativa, tendo como base teórica os Modelos Mentais, de Johnson-Laird (1983), e a Epistemologia Genética, de Piaget (2012). Para tanto, foram tomadas as seguintes fontes de dados: pictórica, por meio de desenhos realizados pelos estudantes antes e após a leitura dos livros literários; expressões orais, em rodas de conversa; e escrita, com descrições dos desenhos após a leitura. Para analisar os dados, criou-se, para cada tema, um quadro explicitando o Modelo Conceitual apresentado pelos autores. Partindo-se do referencial desse modelo, realizou-se a análise dos modelos trazidos pelos estudantes antes da leitura, e se verificou se houve uma mudança desses modelos mentais num momento pós-leitura. Foi constatado que os modelos mentais após a leitura dos livros literários infantis foram modificados, no entanto essas mudanças não foram significativas para eliminar as concepções prévias existentes nas mentes dos estudantes.

O Sistema Solar é um dos temas da Astronomia mais abordados em sala de aula por professores de Ciências. Reconhecendo sua importância, nesta pesquisa buscamos investigar uma proposta de ensino-aprendizagem no tema \"A forma e os movimentos dos planetas no Sistema Solar\", que teve como eixo central a relação entre a observação cotidiana e os modelos científicos atualmente aceitos. Para ajudar na construção dessa proposta, analisamos os Cadernos de Ciências da Proposta Curricular do Estado de São Paulo e as teses e dissertações produzidas no Brasil nas últimas décadas, procurando investigar como estes materiais propõem atividades para o ensino-aprendizagem de conceitos de astronomia. Dialogamos com as ideias de Paulo Freire ao refletir sobre os significados da problematização, do diálogo, da atividade de Extensão Universitária e da importância da formação de sujeitos críticos para compreender o mundo que os cercam. Construímos uma proposta de ensino-aprendizagem com 12 atividades estruturadas a partir da metodologia dos Três Momentos Pedagógicos e realizamos intervenções em um curso para a formação de professores, com o caráter de extensão universitária, oferecido pela Universidade de São Paulo. O objetivo da proposta elaborada foi desenvolver o senso crítico ao relacionar a observação cotidiana com os modelos científicos atualmente aceitos, que geralmente são ensinados em sala de aula. Os dados obtidos na aplicação desta proposta foram analisados com base em três grandes categorias gerais que tinham como focos principais avaliar a percepção das limitações da observação imediata e ingênua e a contradição entre esta e o modelo científico. Os resultados parecem indicar que uma parte dos professores não percebeu a contradição aparente entre a forma da Terra observada no cotidiano e a forma descrita no modelo. Os que percebiam, forneciam argumentos com base em noções de referencial e de escalas e proporção. Embora metade dos professores de nossa amostra tenha percebido esta contradição, a maior parte deles não consegue explicar esta percepção com argumentos científicos ou astronômicos. Na problematização dos movimentos observáveis, todos os professores perceberam a contradição aparente entre o movimento do Sol e os movimentos da Terra aceitos atualmente no modelo. Ainda que apresentassem muitas dificuldades em justificar as razões disso, os professores usaram noções de observação de outros astros e planetas para justificar o modelo. Ao final do curso, percebemos que os professores apresentaram nos debates do tipo Júri Simulado uma série de argumentos trabalhados ao longo do curso, o que parece indicar que, após as atividades, eles passaram a argumentar de maneira menos ingênua sobre as relações entre a observação cotidiana e o modelo. Embora reconheçamos as limitações da proposta apresentada, esta parece se mostrar uma alternativa de grande potencial para intervenções na formação de professores que busquem trabalhar além do conhecimento presente nos materiais didáticos, promovendo um diálogo constante entre o conhecimento astronômico e os aspectos vivenciáveis no cotidiano. / The Solar System is one of the most discussed topics of Astronomy in science classes. Recognizing its importance, this study investigates a teaching-learning proposal about \"the shape and movements of the planets in the Solar System\" which focus on the relationship between daily observation and scientific models currently accepted. We analyze the sciences curriculum proposal of the State of São Paulo and theses and dissertations produced in Brazil in recent decades, describing how these materials propose activities for teaching and learning about astronomy. We have dialogued with the ideas of Paulo Freire in order to reflect on the meanings of \"problematization\", dialogue, university extension and the importance of educating critical subjects to understand the world around them. We created a teaching and learning proposal with 12 structured activities based on the methodology of Three Pedagogical Moments and interventions conducted in a course for the training of teachers, with the character of university extension, offered by the University of São Paulo. The objective of this proposal was develop a critical sense of the subjects relate to everyday observation with currently accepted scientific models, which are usually taught in the classroom. The data obtained in the implementation of this proposal were analyzed based on three main general categories that had as main focus to evaluate the perception of contradiction and limitations of immediate and naive observation and the scientific model. The results seem to indicate that some of the teachers do not realize the apparent contradiction between the Earth\'s shape observed in everyday life and as described in the model. Those who perceived provided arguments based on notions of reference and scales and proportion. Although half of the teachers in our sample have noticed this contradiction, most of them can not explain this perception with astronomical or scientific arguments. In questioning the observable movements, all teachers realized the contradiction between the apparent motion of the Sun and the Earth in the movements currently accepted model. Although presented many difficulties in justifying the reasons that many teachers have used notions of observation of other astronomical bodies and planets to justify the model. At the end of the course, we realize that the teachers presented in the discussions of the type Simulated Jury worked a series of arguments along the course, which seems to indicate that after the activities, they began to argue less naive way relations between everyday observation model. While we recognize the limitations of the proposal, this seems to show a great potential for alternative interventions in teacher seeking work beyond the present knowledge in textbooks, promoting an ongoing dialogue between the astronomical knowledge and aspects in daily life.

Les petits corps du système solaire riches en volatiles incluent plusieurs populations d’objets : les astéroïdes de la ceinture principale, les astéroïdes troyens des planètes géantes, les objets trans-neptuniens (OTNs) et les comètes. Au cours de ces dernières années, l'’idée que leur position actuelle résulte de migrations orbitales plutôt qu’elle ne reflète leur région de formation a progressivement émergée. Spécifiquement, certains astéroïdes pourraient être des comètes, et certaines comètes pourraient être des OTNs. Je présente ici les travaux réalisés au cours de ma thèse pour contraindre la composition (minéralogie de surface et structure interne) de ces différentes populations afin i) de déterminer les liens qui les unissent, ii) comprendre leurs migrations passées et donc, iii) apporter de nouvelles contraintes aux modèles dynamiques décrivant la formation et l’évolution de notre système solaire. À cet effet, j’ai principalement utilisé comme méthode d’analyse l’observation spectroscopique, ainsi que la modélisation des données obtenues et leur comparaison aux données spectrales de météorites et poussières cosmiques étudiées en laboratoire. / The icy small bodies of our solar system encompass several populations of objects : the main belt asteroids, the giant planets Trojans, the Trans-Neptunian Objects (TNOs) and the comets. During recent years, the idea that their present location is the result of orbital migrations rather than their true formation location has progressively emerged. Specifically, some asteroids could be comets, and some comets could be TNOs. Here, I present the studies carried out along my PhD aiming to constrain the physical properties of all these populations in order ultimately i) to determine the link between these populations, ii) bring key constraints to their past orbital evolution and thus iii) key constraints to the formation and evolution models for our Solar System. For that purpose, I have used spectroscopy as a main tool, as well as data modelling using a radiative transfert code and comparison of our astronomical data to laboratory measurements of meteorites and cosmic dust.

One of the most persistent problem in solar physics is the identification of the mechanism that heats the solar corona and accelerates the fast solar wind. Magneto-hydrodynamic (MHD)waves play a crucial role in heating of the solar corona and acceleration of the solar wind. Different types of oscillations have been now observed by various instruments. These are interpreted as due to ubiquitous presence of MHD waves. The magnetic field plays a fundamental role in the propagation and properties of these MHD waves. The topology (structure)of the magnetic fields are different in different regions of the solar atmosphere viz., active regions (high-lying closed magnetic fields), quiet Sun (low-lying closed magnetic fields) and coronal holes (open magnetic fields). The purpose of this dissertation is to study the nature of these propagating MHD waves in different regions of the solar atmosphere. It is believed that polar coronal holes which connects the inner corona and the solar wind, are the source regions of the fast solar wind. The on-disk part of a polar coronal hole can be divided into network and internetwork regions. Long time series(sit-and-stare)data have been obtained from the SUMER/SoHO spectrometer in N iv 765Å and Ne viii 770Å spectral lines to search for the presence of waves in these two different regions from a statistical approach. The network bright regions indicate the presence of compressional waves with a dominant period of ≈ 25 min in both the lines. Moreover, we found that there is a difference in the nature of the wave propagation in the bright (‘network’), as opposed to the dark (‘internetwork’) regions, with the latter sometimes showing evidence of downwardly propagating waves that are not seen in the former. This is consistent with the magnetic topology, as open field lines are rooted in network regions whereas internetwork region has low lying closed field lines. From a measurement of propagation speeds, we found all waves are subsonic, indicating that the majority of them are slow magneto-acoustic in nature. The off-limb part of coronal holes can be divided into plume and inter-plume regions. The simultaneous observations were performed with EIS/Hinode and SUMER/SoHO spectrometer in Fe xii 195Å and Ne viii 770Å spectral lines respectively. We detected the presence of accelerating waves in a polar inter-plume region with a period of 15 min to 20 min in both the spectral lines and a propagation speed increasing from 130 ± 14 km s−1 just above the limb, to 330 ± 140 kms s−1 around 160” above the limb. These waves can be traced to originate from a bright region of the on-disk part of the coronal hole which can be visualized as the base of the coronal funnels. The adjacent plume region also shows the presence of propagating disturbance with the same range of periodicity but with propagation speeds in the range of 135 ± 18 kms s−1 to 165 ± 43 kms s−1 only. We found that the waves within the plumes are not observable (may be getting dissipated) far off-limb whereas this is not the case in the inter-plume region. We suggested that the waves are likely either Alfv´enic or fast magneto-acoustic in the inter-plume regions and slow magneto-acoustic in the plume regions. These results support the view that the inter-plume regions area preferred channel for the acceleration of the fast solar wind. The quiet Sun can be further divided into bright magnetic (network), bright non-magnetic and dark non-magnetic (internetwork) regions. Simultaneous observations were performed in Ca ii filtergram from SOT/Hinode, TRACE 1550Åpassband and with SUMER/SoHO spectrometer in N iv 765ÅandNe viii 770Åspectral lines to study the oscillations in these different regions. We detected the presence of long period oscillations with periods between 15 min to 30 min in bright magnetic regions. The oscillations were detected from chromospheric height to low coronal heights. Power maps showed that low period powers are mainly concentrated in dark regions whereas long period powers are concentrated in bright magnetic regions. We proposed that these 15 min and above periods can propagate up to the coronal heights through ‘magneto¬acoustic portals’. However in this case only with the spectral imaging data, it was not possible to identify the mode of wave propagation. To detect the presence of waves in active regions, we have analysed the imaging and spec¬troscopic data acquired during the total solar eclipse of 2006 and 2009 respectively. We found the oscillations of periods 27 s and 20 s in imaging data obtained in green (Fe xiv 5303Å) and red (Fe x 6374Å) coronal emission lines respectively. Significant oscillations with high proba¬bility estimates were detected at boundary of active region and in the neighbourhood, rather than within the loops itself. We also reported the detection of oscillations in intensity, velocity and line width having periods in the range of 25 s to 50 s with spectroscopic data again obtained in green and red coronal emission lines. These high frequency oscillations were interpreted in terms of presence of fast magneto-acoustic waves or torsional Alfv´en waves. These detected propagating MHD waves may carry sufficient energy to heat the corona and provide enough momenta to accelerate the fast solar wind. In addition, these waves may also provide input for the measurement of coronal magnetic field using the technique of ‘coronal seismology’.