Dissertations / Theses on the topic 'Lighting ratio'

The greenhouse industry is interested in light emitting diodes (LEDs) as a light source supplement to solar light to improve plant growth and development. Before LEDs can be adopted as supplemental light for greenhouse crops, plant responses to LED spectral quality need to be investigated. Tomato and cucumber seedlings were grown under different supplemental blue and red photon flux ratios (B:R ratios) under high (16-19 mol m⁻² d⁻¹) and low (5-9 mol m⁻² d⁻¹) solar daily light integrals (DLIs). The supplemental daily light integral was 3.6 mol m⁻² d⁻¹. A treatment without supplemental light served as a control. Both tomato and cucumber seedlings had increased growth rate and improved morphology when grown under the supplemental LED light compared to the control. However, no significant differences were observed for any growth and morphological parameters measured in this study between the different B:R ratios for both cucumber and tomato transplants under high DLI conditions. Cucumber seedlings showed a tendency to decrease dry mass, leaf number and leaf area under low DLI conditions with increasing B:R ratio. Tomato seedlings did not show any differences between the different B:R ratios under low DLI conditions. Seedlings growth and morphology under supplemental LED light were compared to those under supplemental high pressure sodium (HPS) light. Cucumber seedlings under supplemental HPS light had greater shoot dry mass than those under the supplemental red LED light. Tomato shoot dry mass showed no differences between the HPS and red LED supplemental light treatments. Cucumber seedlings were also grown under supplemental LED pulsed lighting and supplemental LED continuous lighting. Cucumber seedlings showed no differences in shoot dry mass and net photosynthetic rate between the treatments. Collectively, these studies concluded that red LED is preferred for supplemental lighting and the increase of blue light does not offer any benefits unless the efficiency of blue LEDs largely exceeds the red LEDs. The results of this research can be used for fixture development by LED manufactures and as a decision making tool for the adoption of supplemental LED lighting by greenhouse growers.

The circular economy is promoted by the EU, governments, and businesses all over the world as a concept to reach a sustainable future. The concept is embedded into the UN Sustainable Development Goals for 2030 and aims to decouple economic growth and environmental pressure. Many studies have been conducted on the circular economy in recent years but the research on the actual environmental performance of the concept is limited. To move forward with the concept of the circular economy and reach a sustainable future, the environmental performance must be investigated. In this thesis, the environmental impact of circularity in products is investigated by comparing the environmental impact from one circular and one linear product case. To achieve this, the environmental impact and the degree of circularity is calculated with two different methods. The circularity is calculated with a circularity indicator called the Linear Flow Ratio and the environmental impact is assessed with the environmental evaluation technique Life Cycle Assessment (LCA). In the LCAs, the cases are compared for different environmental impact categories (e.g. global warming). The product that is investigated is an LED lighting fixture from the company 2P1. The circular case is based on a leasing business model and includes remanufacturing, reuse and recycling. The linear case includes production, sales, use, and disposal. The LCA results show that the environmental impact from the circular case is lower for all environmental impact categories. The environmental impact is almost exclusively from the manufacturing phase (including extraction and production of raw materials) and the use phase. The circularity results from the Linear Flow Ratio show contradicting results, presenting that the degree of circularity is higher for the linear case. By comparing the results to calculations from another circularity indicator (Material Circularity Indicator), it is concluded that a unified framework for circularity measurements is required.
Cirkulär ekonomi är introducerat av EU, länder och företag över hela världen som ett koncept för att nå en hållbar framtid. Den cirkulära ekonomin är en del av arbetet mot agenda 2030 för hållbar utveckling och strävar efter att frånkoppla ekonomisk tillväxt från miljöpåverkan. Det har forskats mycket på cirkulär ekonomi under de senaste åren men studier som undersöker det miljömässiga utförandet av konceptet saknas. För att fortsätta att utveckla konceptet och för att nå en hållbar framtid så måste den miljömässiga påverkan från cirkularitet undersökas. I denna studie undersöks miljöpåverkan från cirkularitet hos produkter genom att jämföra miljöpåverkan från ett cirkulärt och ett linjärt fall. Miljöpåverkan och cirkularitetsgraden beräknas med två olika metoder. Cirkulariteten beräknas med cirkularitetsindikatorn Linear Flow Ratio och miljöpåverkan analyseras men livscykelanalys. I livscykelanalyserna värderas miljöpåverkan för de två fallen för olika påverkanskategorier (t.ex. global uppvärmning). Produkten som undersökt är en LED-armatur från företaget 2P1. Det cirkulära fallet basers på uthyrning av armaturerna och innehåller renovering, återanvändning och återvinning. Det linjära fallet innehåller produktion, försäljning, användning och bortskaffande av produkten. Resultaten från livscykelanalyserna visar att det cirkulära fallet medför mindre miljöpåverkan för alla kategorier. Miljöpåverkan kommer nästan enbart från produktion (inklusive material) samt användning. Cirkularitetsresultaten från Linear Flow Ratio visar motsägelsefulla resultat då det linjära fallet har en högre cirkularitetsgrad än det cirkulära fallet. Genom att jämföra resultaten med beräkningar från en annan cirkularitetsindikator (Material Circularity Indicator) kan det fastställas att ett enhetligt ramverk för beräkning av cirkularitet är nödvändigt framöver.

Daylight harvesting is an essential strategy that is often used to enhance both the design and performance of an architectural project. Windows, as crucial architectural elements, not only admit natural light into spaces but also provide the occupants with visual connections. However, the excessive usage of windows brings an uncontrolled amount of solar energy to the spaces and negatively affect the building's energy performance. When utilizing passive design strategies such as daylight harvesting, several parameters, including the electrical lighting system, can impact the outcome. The current study investigates the role of lighting systems on daylight harvesting's effectiveness and their impact on window dimension and total energy consumption. In this study, the optimum window-to-wall ratio of an open office in the presence of two different light sources (LED and fluorescent) is explored through a computer simulation method. A combination of tools including AGi32, ElumTools, OpenStudio, EnergyPlus, Radiance, and MATLAB helps to conduct the simulation and deliver optimal results. In the results and conclusion chapter, the study provides guidelines to specify optimal window percentages considering two lighting systems in each cardinal direction. Importantly, the guideline focuses only on energy performance and not on the spatial quality of the design.
Master of Architecture
Harnessing daylight with the use of windows helps to offset parts of the electric lighting needs, and decrease the total building energy consumption. This is accomplished by using glazed materials to admit daylight and lighting control systems, which can respond to the dynamic light level. However, improper implementation of a passive daylighting strategy may cause increased energy consumption. Sunlight is accompanied by solar heat radiation which can increase the HVAC load of a space and compromise the energy savings achieved by daylighting. Therefore, a balance between solar heat and light gain is required to fully take advantage of solar energy without reverse impacts. Concerning the mentioned balance, recent advancements in lighting technology question the effectiveness of natural light in reducing whole-building energy consumption. Due to the high energy efficiency of LED luminaires, lighting power consumption is rather low, even when the lighting system operates at full capacity. Therefore, it is unclear whether the solar energy coming through glazed materials works to the advantage or disadvantage of total building energy consumption. This study hypothesized that the total energy consumption of an open office with LED luminaires would be less in absence of solar energy compared to a scenario which utilizes the solar energy. A simulation-based methodology, using a combination of photometric computation and building energy simulation tools, was utilized to examine the hypothesis and explore the impacts of lighting systems on the optimum window-to-wall ratio. The results provide a helpful guideline which highlights the impact of lighting systems on window dimensions and their mutual effect on whole-building energy consumption. Although the optimum window-to-wall ratios suggested by this study only concern energy consumption, integration of them with occupants' preferences can propose an acceptable window-to-wall ratio that satisfies both design quality and performance of a building.

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Os sistemas de iluminação pública (IP) no Brasil atravessam um momento de mudanças significativas, que implicam em novos paradigmas, desafios e perspectivas para o setor. Essas transformações começam com a transferência dos ativos de IP para os municípios, exigindo que os gestores municipais estejam preparados e capacitados para assumir esse serviço público essencial que anteriormente não era de sua responsabilidade. Além disso, novas tecnologias de iluminação, como os diodos emissores de luz (LEDs), surgem como alternativa às tecnologias convencionais, acarretando muitos impactos e alterações de conceitos no projeto, gestão e manutenção dos sistemas de IP. Assim, esta tese traça um panorama da iluminação pública no país, abrangendo questões referentes à gestão e manutenção do sistema, enfatizando os desafios ligados à transferência dos ativos de iluminação pública para os municípios, além da complexidade inerente à mudança de tecnologia para os LEDs. A discussão é organizada em duas vertentes principais: a gestão da IP, com ênfase nos desafios associados à transferência dos ativos; e a consolidação de novas tecnologias, sobretudo os LEDs. Nesse âmbito, com o objetivo de contribuir para uma utilização mais eficiente dos sistemas de iluminação, este trabalho propõe a consolidação da fotometria mesópica na elaboração de projetos luminotécnicos de IP, uma vez que, nesses casos, é comum deparar-se com condições de baixa luminância, nas quais a sensibilidade espectral da visão humana é diferente das condições supostas pela fotometria clássica. Neste sentido, procura-se explorar em detalhes a recomendação CIE 191:2010, que propõe multiplicadores de correção para a adaptação de grandezas fotométricas convencionais em grandezas mesópicas. Todavia, para se obter tais multiplicadores, é necessária a obtenção da relação entre os fluxos escotópico e fotópico da fonte luminosa (relação S/P), o que exige equipamentos especiais não facilmente disponíveis à maior parte dos projetistas. Com o objetivo de contornar essa dificuldade, esta tese de doutorado propõe uma equação geral que permita realizar o cálculo de S/P em função da temperatura de cor correlata e do índice de reprodução de cor da fonte de luz a ser empregada, que são informações normalmente disponibilizadas nos catálogos de fabricantes ou embalagens de lâmpadas comerciais. A equação encontrada apresentou coeficientes de correlação e de determinação próximos da unidade, o que lhe garante boa confiabilidade. Pela obtenção da relação S/P com auxílio da técnica proposta, um projeto luminotécnico típico tem sua rotina alterada, algo que é demonstrado e exemplificado ao final do texto.
The street lighting systems in Brazil are going through a time of significant changes that involve new paradigms, challenges and prospects for the sector. These changes begin with the transfer of street lighting assets to municipalities, demanding that municipal managers are prepared and able to manage this essential public service that previously was not your responsibility. In addition, new lighting technologies such as light-emitting diodes (LED) are an alternative to conventional technologies, resulting in many impacts and changes of concepts in the design, management and maintenance of street lighting systems. Thus, this thesis provides an overview of street lighting in Brazil, covering issues relating to the management and maintenance of the system, emphasizing the challenges linked to the transfer of street lighting assets to the municipalities, in addition to the inherent complexity of LED technology. The discussion is organized into two main areas: the management of system, with emphasis on the challenges associated with the transfer of assets; and the consolidation of new technologies, especially the LED. In this context, in order to contribute to a more efficient use of lighting systems, this thesis proposes the consolidation of mesopic photometry in the development of street lighting projects, since in such cases it is common to encounter poor conditions luminance, in which the spectral sensitivity of human vision is different from the conditions in the classical photometry. In this sense, it is covered in detail the CIE 191:2010 technical report, which proposes correction factors for the adaptation of conventional photometric quantities in mesopic quantities. However, to obtain such factors, it is required to obtain the relationship between the scotopic and photopic luminous flux of light source (S/P ratio), which requires special equipment not readily available to most lighting designers. Thus, this PhD thesis proposes a general equation that provides the S/P ratio as a mathematical function of correlated color temperature and color rendering index of the light source, which are information usually available in catalogs of manufacturers or products packaging. The proposed equation showed correlation coefficient and coefficient of determination parameters closed to unity, which guarantees good reliability. By obtaining the S/P ratio with the aid of proposed technique, a typical lighting design has changed his routine, something that is demonstrated and exemplified in final of the text.

Syfte: Det råder brist på utvärderingar av belysningsanläggningar, vilket är ett viktigt verktyg för att få förståelse för brukares upplevelse, säkerställa en anläggnings kvalitet och förvärva kunskap till kommande projekt. Inomhusmiljön påverkar i hög grad människans hälsa och välbefinnande, där belysningen är en stor påverkningsfaktor. I samverkan med konsultföretaget WSP har utvärderingar genomförts i två kontorsmiljöer på Domstolsverket i Jönköping. Målet med studien var att undersöka hur en kvalitativ och kvantitativ utvärderingsmetod stod i relation till brukarnas uppfattningar av visuell trivsel. Metod: En kombination av kvalitativa och kvantitativa metoder användes för att förstå ljusmiljöns perceptiva och fysikaliska uppbyggnad, samt förstå brukarnas subjektiva uppfattning. Använda metoder var enkät, observation utifrån PERCIFAL och mätning av luminansförhållande. Resultat: Inga tydliga samband återfanns mellan brukarnas uppfattning av visuell trivsel och observation, eller analyserade. Svaga tendenser fanns dock på att i de områden observatörerna upplevde ljusare, var även respondenternas attityd till den visuella miljön mer positiv. Både höga och låga luminansförhållanden resulterade i att respondenterna erhöll en positiv attityd till den visuella miljön och välbefinnande. En positiv inställning till ljusmiljön visade sig gynna den visuella trivseln. Starkast samband fanns mellan inställning till ljusmiljön och upplevelsen av den visuella miljön, där en positiv inställning gynnade upplevelsen av den visuella miljön. Konsekvenser: Studiens slutsats är att varken en mätning eller observation är tillräcklig att användas enskilt för att säkerställa brukarnas visuella trivsel, eller för att beskriva hur ljusmiljön uppfattas av användarna. Därför rekommenderas det att inkludera brukare vid utvärdering, och att utföra mer omfattande utvärderingar för att generera kunskap kring kopplingen mellan mätbart ljus, perceptiv upplevelse och subjektiv uppfattning av visuell trivsel. Om utvärderingar och efterkontroller som även tar hänsyn till brukarnas subjektiva uppfattning prioriteras högre i byggprocessen, kan det säkerställa att ljusmiljöer erhåller ännu högre kvalitet. Begränsningar: Att enkäten utfördes på distans kan ha påverkat resultatet, samt att respondenterna ofta valde det neutrala mittenalternativet. Vissa begrepp kan även ha tolkats på annat sätt än förväntat. Observation och mätning utfördes endast vid ett tillfälle och inte i samtliga zoner där respondenterna var positionerade. Observation och mätning utgick endast från belysningens grundinställningar och bildskärmarna var inte tända vid detta tillfälle. Valet av antalet lokaler och skillnad i användningsfrekvens kan också ha påverkat resultatet. Mätning av luminans visade sig vara mer komplext än vad som förväntats. Intervjuer hade troligtvis givit en djupare förståelse kring det undersökta fenomenet än vad som generades från enkäten. Resultatet är enbart tillämpbart i det undersökta fallet och är därmed inte generellt giltigt.
Purpose: There is a shortage of evaluations of lighting constructions, which are crucial to understand the user, ensure the environmental quality and generate knowledge for future projects. The users’ well-being is affected by the indoor environmental quality, where the lighting has a major impact. In collaboration with the consulting company WSP, evaluations have been executed in two office environments at Domstolsverket in Jönköping. The aim with the study was to investigate how one qualitative and onequantitative evaluation method is related to the users’ perceptions of visual well-being. Method: A combination of qualitative and quantitative methods were used to understand the perceptive and physical construction of the lighting environment, and to understand the users’ subjective experience. Used methods were questionnaire, observation based on PERCIFAL and luminance ratio measuring. Findings: No significant connection were found between the users’ experience of visual well-being and the observation, or between the luminance ratios. There were weak tendencies that those areas of which the observers experienced the brightest, the users experienced the visual environment in a more positive way. Both high and low luminance ratios resulted in a positive attitude to the visual environment and the wellbeing. A positive attitude to the lighting environment favored the visual well-being. The strongest connections were found between the attitude to the lighting environment and the experience of the visual environment, where a positive attitude favored the experience of the visual environment the most.  Implications: Since either the measuring or the observation hadn’t any connection to the users’ subjective experience, the conclusion of the study is that either luminance ratios or a visual evaluation individually are sufficient to ensure the users visual wellbeingor to describe how the lighting environment is experienced by the users.Therefore, it is recommended to include users in evaluations, and to execute more comprehensive evaluations to generate more knowledge regarding the connection between measurable light and perceptive and subjective experience of visual wellbeing. If this is included in the process, it might increase the quality of the lighting environment. Limitations: The questionnaire was responded to at a distance and the respondents tended to choose the neutral central option and those factors might have affected the result. Some terms might also have been interpreted in another way than expected. The observation and the measuring were only executed once, and not in all the areas where the respondents were positioned. While measuring and observing, only the most used light setting was used and the computer screens where not on. Luminance measuring was more complex than expected. Interviews might have given a deeper understanding about the investigated phenomenon than what was generated from the questionnaire.The result is only applicable in this specific case and therefore not universal.

Thesis (PhD (Electrical and Electronic Engineering))--University of Stellenbosch, 2010.
ENGLISH ABSTRACT: South Africa and Australia are now the two remaining countries bidding for the Square Kilometre Array (SKA), the biggest and most sensitive project ever undertaken in radio astronomy. The South African SKA is demonstrating its technology capabilities through the Karoo Array Telescope (KAT or MeerKAT). The development of KAT is taking place in stages to optimise design and minimise risks at each stage. An array of seven 12 m antennas will be complete by the end of 2009, called KAT-7. The following phase will see the construction of MeerKAT, which will lead to eighty arrayed dishes. Lightning and RFI studies for KAT-7 are the focus of this dissertation. Due to the extent and complexity of the South African demonstrator project, these studies have largely been conducted on a single structure. Parameters for the dish antenna and pedestal design changed throughout their development. To be effective, the doctoral research had to track these changes appropriately. A Method of Moments frequency domain computational electromagnetic code, FEKO, is used throughout the study. The consequences of direct and indirect lightning strikes are examined for the KAT-7 structure. Important FEKO model verification is achieved through measurement of physical scale models in an anechoic chamber. The microwave simulation code, CST, gives direct comparison of FEKO results by using a finite volume time domain method of calculation. Using frequency domain analysis on these models, the lightning down conductor design over the dish antenna bearings is optimised with cost-effectiveness as one driving parameter. RFI coupling levels for different designs are compared to each other to identify areas requiring RFI mitigation. Analysis of resonances enables evaluation of the mitigation at frequencies sensitive to radio astronomy. A Sommerfeld integral ground plane is used together with the computational model to investigate the use of the concrete foundation steel reinforcing as part of the lightning earthing electrode system. Different interconnections of the steel reinforcing elements are critically evaluated. The KAT-7 design incorporated clear lightning protection and RFI mitigation policies derived from recommendations contained within this dissertation.
AFRIKAANSE OPSOMMING: Suid-Afrika en Australie is nou die oorblywende twee lande wat bie vir die Vierkante Kilometer Reeks (SKA), die grootste en mees sensitiewe projek nog ooit in radio astronomie onderneem. Die Suid Afrikaanse SKA demonstreer sy tegnologiese bekwaamheid met die Karoo Reeks Teleskoop (KAT of MeerKAT). Die ontwikkeling van KAT vind plaas in fases om die ontwerp te optimaliseer en risikos te minimaliseer met elke fase. ’n Reeks van sewe 12 m antennas, genaamd KAT-7, sal teen die einde van 2009 klaar wees. Die volgende fase behels die konstruksie van MeerKAT, wat sal lei tot ’n tagtig-skottel reeks. Die fokus van hierdie proefskrif hanteer weerlig en radiofrekwensie steurings (RFS) vir KAT-7. As gevolg van die omvang en kompleksiteit van die Suid-Afrikaanse demonstreerder projek, is die studies hoofsaaklik op een struktuur gedoen. Parameters vir die antenna-skottel en -voetstuk ontwerp het met hul ontwikkeling deurgaans verander. Om effektief te wees, moes die doktorale navorsing hierdie veranderinge toepaslik volg. ’n Metode-van-Momente frekwensiedomein rekenaar elektromagnetiese kode, FEKO, is deurgaans met die studie gebruik. Die gevolge van direkte en indirekte weerligslae vir die KAT-7 struktuur is ondersoek. Belangrike FEKO model bevestiging is bereik met metings van skaalmodelle in ’n anego¨ıse kamer. Die mikrogolf-simulasie kode, CST, gee ’n direkte vergelyking met die FEKO resultate deur ’n eindige-volume-tyd-domein metode van berekening te gebruik. Met behulp van frekwensiedomein analise van hierdie modelle, is die weerligafleierontwerp oor die antenna-skottel laers ge-optimaliseer, met koste-effektiwiteit as een van die drywingsparameters. RFS koppelingsvlakke vir onderskeie ontwerpe is teen mekaar opgeweeg om areas te identifiseer wat RFS tempering benodig. Analise van resonansies stel die evaluering van die tempering in staat teen frekwensies wat sensitief is vir radio astronomie. ’n Sommerfeld integrale grondvlak word saam met die rekenaarmodel gebruik om die insluiting van die beton se staalversterking as deel van die aardingselektrodestelsel te ondersoek. Verskillende bindmetodes van die onderlinge staalversterkingselemente word krities ge¨evalueer. Die KAT-7 ontwerp inkorporeer duidelike weerligbeveiligings- en RFS temperingstrategie ¨e, komende van aanbevelings in hierdie proefskrif omskryf

Electrical activity at volcanoes has been recently recognized as a potential new remote sensing technique for plume-forming eruptions. Volcanic electrical activity takes place in the conduit and plume and therefore has the benefit of being a direct indicator of surface activity. This is unlike seismic signals, which indicate magma/gas movement underground, and infrasound signals, which indicate a surface explosion but not necessarily the formation of an ash plume. There are two distinct types of volcanic electrical discharges: volcanic lightning and continual radio frequency (CRF) impulses. This dissertation explores the relationships between these two electrical signals and other commonly monitored volcanic parameters. For volcanic electrical activity to be widely adopted into monitoring platforms it is important to understand how electrical discharges at volcanoes are related to other monitored signals. I present a case study of the electrical activity at Sakurajima Volcano, Japan. The lightning mapping array (LMA) is used to record both lightning and CRF. I relate CRF to ash properties and show that CRF corresponds to eruptions containing more juvenile magma that has undergone milling as it is transported out of the conduit. Seismic, infrasound, and video data are used in conjunction with multivariable statistical methods on a suite of electrical parameters to show that high levels of volcanic electrical activity are related to eruptions with large infrasound signals (> 107 J), high initial velocities (> 55 m/s), and relatively tall plume heights (> 1 km). Finally, an examination of globally detected lightning at Bogoslof Volcano, AK shows the potential for volcanic lightning in plume tracking (0-100 km), even after the end of the explosive phase of the eruption.

Orientador: Galeno José da Silva
Coorientador: Luiz Fernando de Mattos
Banca: José Roberto Dale Luche
Banca: Nelson Jesuz Ferreira
Resumo : As previsões de descargas elétricas atmosféricas constituem um desafio na fisica e ciências afins. Campanhas de pesquisas em campo e instalação de redes de sensores têm formado um histórico de observações com um ótimo grau de precisão destes eventos. Apesar da grande quantidade de dados gerados, não se observam muitas publicações sobre modelagem de queda de raios nas torres de linhas de transmissão de energia elétrica. Neste trabalho, busca-se começar a preencher esta lacuna com um estudo para obtenção de um índice potencial de impacto de raios em torres de linhas de transmissão de energia elétrica. Um experimento fatorial completo combinado com as saídas de modelos regionais de previsão de tempo foi utilizado na busca deste índice. Os resultados, apesar da descoberta de poderem ser usados no diagnóstico e previsão de tornados, não foram ainda conclusivos para os objetivos deste trabalho. A ampliação na quantidade das amostragens, a realização de mais experimentos e novas pesquisas podem contribuir para a melhoria do índice potencial de impacto de raios em torres de linhas de transmissão de energia elétrica, já que esta técnica mostrou potencial para auxiliar as pesquisas na modelagem deste fenômeno
Abstract: The forecast of atmospheric electrical discharges is a challenge in Physics and related Sciences. It is known that field campaigns and installation of the sensor network have shown great precision degree by the historical of the observation. Despite having large amount of data, we have had many scientific papers on modeling of lightning towers in electric transmission lines. This work aims to do a study for obtaining a Potential Index of Impacts Lightning in Electric Transmission Lines. In order to get this Index, an accurate factorial experiment was combined with regional forecast models output. As a result, although the discovery can be used for diagnosis and tornadoes forecasting, its has not been concluded by this work target yet. Having shown the technique can help the modeling research, an expansion of sample as well as new experiment and news research can contribute more for Index improvement
Mestre

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As previsões de descargas elétricas atmosféricas constituem um desafio na fisica e ciências afins. Campanhas de pesquisas em campo e instalação de redes de sensores têm formado um histórico de observações com um ótimo grau de precisão destes eventos. Apesar da grande quantidade de dados gerados, não se observam muitas publicações sobre modelagem de queda de raios nas torres de linhas de transmissão de energia elétrica. Neste trabalho, busca-se começar a preencher esta lacuna com um estudo para obtenção de um índice potencial de impacto de raios em torres de linhas de transmissão de energia elétrica. Um experimento fatorial completo combinado com as saídas de modelos regionais de previsão de tempo foi utilizado na busca deste índice. Os resultados, apesar da descoberta de poderem ser usados no diagnóstico e previsão de tornados, não foram ainda conclusivos para os objetivos deste trabalho. A ampliação na quantidade das amostragens, a realização de mais experimentos e novas pesquisas podem contribuir para a melhoria do índice potencial de impacto de raios em torres de linhas de transmissão de energia elétrica, já que esta técnica mostrou potencial para auxiliar as pesquisas na modelagem deste fenômeno
The forecast of atmospheric electrical discharges is a challenge in Physics and related Sciences. It is known that field campaigns and installation of the sensor network have shown great precision degree by the historical of the observation. Despite having large amount of data, we have had many scientific papers on modeling of lightning towers in electric transmission lines. This work aims to do a study for obtaining a Potential Index of Impacts Lightning in Electric Transmission Lines. In order to get this Index, an accurate factorial experiment was combined with regional forecast models output. As a result, although the discovery can be used for diagnosis and tornadoes forecasting, its has not been concluded by this work target yet. Having shown the technique can help the modeling research, an expansion of sample as well as new experiment and news research can contribute more for Index improvement

This thesis evaluates the Lightning II and the Radio Baton gestural controllers for musical applications within two main perspectives. The first involves a technical specification of each in terms of their construction and sensing technology. This step, along with an analysis of the insights by long-term users on the controllers in question, provides an understanding about the different musical contexts each controllers can be and have been used in. The second perspective involves studying the Radio Baton and the Lightning within a specific musical context, namely that of a simulated acoustic percussion instrument performance. Three expert percussionists performed basic percussion techniques on a real drum, a drum-like gestural controller (the Roland V-Drum), the Radio Baton and the Lightning II. The motion capture and audio data from these trials suggest that certain acoustic percussion playing techniques can be successfully transferred over to gestural controllers. This comparative analysis between gestural controllers adds to the ongoing discussion on the evaluation of digital musical instruments and their relationship to acoustic instruments.

Orientador: Jose Pissolato Filho
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
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Resumo: Este trabalho apresenta uma análise computacional usando a técnica numérica TLM (Transmission Line Method) do comportamento das tensões transitórias em sistemas de aterramento, quando submetidas a fenômenos impulsivos do tipo descargas atmosféricas. É apresentada uma revisão bibliográfica sobre o tema e os diferentes métodos numéricos usados para modelar sistemas de aterramento. A técnica numérica TLM é apresentada, assim como, as equações para a determinação dos parâmetros usados nas simulações e o fluxograma do programa computacional desenvolvido. O programa foi escrito em Fortran e validado comparando os resultados obtidos com simulações e testes experimentais publicados por outros autores. Com o objetivo de obter o comportamento das tensões transitórias sobre diferentes situações, foi estudada a influência de alguns parâmetros no comportamento transitório das malhas de aterramento
Abstract: This work, by using the TLM (Transmission Line Method) numeric technique, presents a computational analysis of the transitory tensions behavior in grounding systems, when submitted to impulsive phenomena of the atmospheric discharge type. A bibliographical revision on the theme and the different numeric methods used for modelling grounding systems, including the TLM numeric technique, are explained, as well as the equations for the determination of the parameters used in the simulations and the flowchart of the software developed. The program written in Fortran was validated comparing simulations and experimental tests published by other authors. For the purpose of obtaining the transitory tensions behavior in different situations, we studied the influence of some parameters in the transitory behavior of grounding meshes
Mestrado
Energia Eletrica
Mestre em Engenharia Elétrica

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Este trabalho apresenta o desenvolvimento de um processo de tratamento com plasma para melhorar ametalização química de placas de circuito impresso (PCI). A pluma de plasma é gerada em argônio a partir da descarga de barreira dielétrica (DBD) promovida entre uma agulha cirúrgica e um cilindro usando capilar de borosilicato como dielétrico. A tensão picoa-pico aplicada foi de 5 kV, com forma de onda senoidal na frequência de 37 kHz e potência de descarga em torno de 765 mW. O substrato é um composto de fibra de vidro e resina epóxi. Com incidência perpendicular da pluma de plasma na superfície, o diâmetro da área tratada circular é de 10 mm. Desta forma, o ângulo de contato reduz de 75 ° a 45 ° com 3 s de interação entre superfície da amostra e a ponta do plasma e o ângulo atinge o mínimo de 33 ° após 180 s de tempo de tratamento. A metalização química foi feita com banhos seqüenciais de solução de paládio e finalizada com banho de solução aquosa de cobre. Testes de adesão padrão mostraram uma forte adesão das camadas de metal nas superfícies previamente tratadas com as plumas de plasma. Esta adesão melhora com o tempo de tratamento. A melhoria na metalização foi observada em superfície plana e também em furos usados para conectar diferentes camadas em PCIs. A área metalizada na superfície dos buracos é maior nos orifícios tratados. Quanto maior o tempo de tratamento, maior é essa área. Todos os resultados indicaram que a técnica de tratamento por plasma de placas de fibra de vidro melhora a sua metalização química pelo cobre, levando a uma adesão mais uniforme e eficaz do metal à superfície com um método ambientalmente amigável
This work reports the development of a plasma treatment process to improve the chemical metallization of printed circuit boards (PCB). The plasma plume is generated in argon from a dielectric barrier discharge (DBD) promoted between a surgical needle and a cylinder using a borosilicate capillary as dielectric. The applied peak-to-peak voltage was 5 kV, with sinusoidal waveform at 37 kHz frequency and power in the discharge around 765 mW. The substrate was a composite of fiberglass and epoxy resin. With perpendicular incidence of the plasma plume on the surface the diameter of the circular treated area was 10 mm. In this area the contact angle reduces from 75° to 45° with 3 s of the plasma-surface interaction and the angle reaches the minimum of 33° after 180 s of treatment time. Chemical metallization was made with sequential baths of solution of palladium and finished with bath of aqueous solution of copper. Standard adhesion tests showed a strong adhesion of the metal layer on surfaces previously treated with the plasma plumes. This adhesion improves with the treatment time. The improvement in the metallization was observed on flat surface and also in holes used to connect different layers in PCB’s. The metallized area on the surface of the holes is larger in treated holes. The longer the treatment time the larger is this area. All these results indicated that the technique of plasma treatment of fiberglass boards improves its chemical metallization by copper leading to a more uniform and effective adhesion of the metal to the surface with an environmental friendly method

Cilj istraţivanja bio je da se ispita uticaj svetlosnog programa (konstantnog – KS i opadajuĆe- rastuĆeg - ORS), gustine obroka i gustine naseljenosti i njihove interakcije na proizvodne i klaniČne osobine brojlerskih piliĆa, kvalitet mesa i ošteĆenje tabanskih jastuČiĆa.Istraţivanja su sprovedena na farmi piliĆa Donji Crnci nadomak Podgorice u tri ogleda: u prvom su ispitivani efekti svetlosnog programa i gustine obroka, u drugom programi svetla i gustina naseljenosti piliĆa, a u treĆem program svetla i gustina obroka (smeše sa standardnim i poveĆanim sadrţajem energije i proteina, pri Čemu je odnos energija : protein bio konstantan). U svakom ogledu bilo je 320 piliĆa linijskog hibrida Cobb 500, mešanih po polu, a ogledi su trajali 42 dana. U sva tri ogleda formirane su po Četiri grupe sa Četiri ponavljanja i u svakoj grupi bilo je 80 jednodnevnih piliĆa.Proizvodni parametri (telesna masa, utrošak hrane i uginuĆa) praĆeni su u svim ogledima, a izraČunati su konverzija hrane i proizvodni indeks. Telesne mase su merene u uzrastu od 1; 7; 14; 21; 28; 35 i 42 dana. Utrošak hrane utvrčivan je na kraju perioda primene pojedinih smeša, i to: 14. dana koliČina konzumirane starter smeše, 35. dana grovera i 42. dana finišer smeše. Mortalitet je odrečivan beleţenjem broja uginulih piliĆa u toku trajanja ogleda. Na osnovu telesnih masa, konverzije hrane i mortaliteta izraČunati su proizvodni indeksi.Na kraju svakog ogleda, sa 6 nedelja starosti, piliĆi su izmereni pojedinaČno, izraČunati su proseci tretmana, a zatim je od svakog tretmana izdvojeno 20 piliĆa (10 muških i 10 ţenskih) radi ispitivanja klaniČnih karakteristika. Pre klanja piliĆi su gladovali 12 sati. Nakon klanja i ČišĆenja trupovi su ohlačeni na 40C u toku 24 sata, a potom obračeni kao: „klasiČna obrada” „spremno za peČenje” i „spremno za roštilj”.Pri konfekcioniranju trupova izdvojena je abdominalna mast, izmerene mase obračenih trupova i dobijeni randmani. Radi utvrčivanja prinosa i udela osnovnih i sporednih delova trupa izvršeno je rasecanje ohlačenih trupova. Ocena konformacije trupova izvršena je na osnovu utvrčenih apsolutnih mera: duţine piska, duţina kobilice, dubina grudi i obim bataka. KorišĆen je indeks koji predstavlja odnos ţive mase pre klanja i posmatrane mere (g/mm).U ogledu II izvršeno je i fiziČko ispitivanje kostiju, na femuru nakon izdvajanja od skeleta brojlera, a u ogledu III odrečeni su sadrţaj vlage, sadrţaj ukupne masti, ukupnog pepela i ukupnih proteina belog i crvenog mesa, na uzorcima mišiĆnog tkiva grudi i karabataka od 5 muških i 5 ţenskih trupova u svakom tretmanu (ukupno 20).  Rezultati ukazuju da svetlosni program nije statistiČki znaČajno uticao na završne telesne mase u ogledima I i II, dok su u ogledu III veĆe mase utvrčene kod piliĆa tovljenih pri KS. Primena ORS uticala je na usporavanje stope rasta u prvom periodu tova, a kao rezultat kompenzacionog porasta bez uticaja na završne mase, sem u treĆem ogledu. Bolju konverziju hrane u periodu ishrane finišerom postigli su piliĆi u ogledu I pri ORS nego pri KS, kao i u ishrani starterom u ogledu III. Svetlosni programi u ogledu II nisu uticali na konverziju hrane i mortalitet piliĆa.Gustina obroka nije uticala na završne mase, konverziju hrane, mortalitet i proizvodni indeks. Kod piliĆa hranjenih obrocima sa višim sadrţajem proteina i energije utvrčene su veĆe telesne mase na kraju tova (P<0.01). Gustina obroka u ogledima I i III nije imala uticaj na konverziju hrane, mortalitet i proizvodni indeks. Znatno je veĆa završna masa piliĆa tovljenih pri gustini naseljenosti od 12 grla/m2 (2667,08 g) nego pri 17 grla/m2 (2435,76 g) i razlike su bile statistiČki visoko znaČajne. Nije utvrčen uticaj gustine naseljenosti na konverziju hrane, mortalitet i proizvodni indeks.Ispitivani faktori (svetlo, gustina obroka i gustina naseljenosti) nisu uticali na randmane, ali jesu interakcije nekih od njih. U svim ogledima utvrčen je manji udeo abdominalne masti pri ORS nego pri KS, ali bez statistiČke znaČajnosti. Gustina obroka i gustina naseljenosti nisu uticali na sadrţaj abdominalne masti. VeĆi je sadrţaj abdominalne masti u svim ogledima bio kod ţenskih nego muških piliĆa. Udeo grudi veĆi je pri KS nego pri ORS, ali su razlike statistiČki znaČajne samo u treĆem ogledu. Gustina obroka i gustina naseljenosti nisu uticale na udeo grudi. Udeo bataka bio je veĆi kod piliĆa tovljenih pri ORS nego pri KS, ali su razlike statistiČki znaČajne samo u prvom ogledu. Udeo karabataka u prvom i drugom ogledu nije se znaČajno razlikovao izmeču svetlosnih programa, dok je u treĆem bio veĆi pri ORS nego pri KS (P<0.01). Nije utvrčen uticaj gustine naseljenosti i gustine obroka na udeo bataka i karabataka. Kod muških piliĆa utvrčen je veĆi udeo bataka, a kod ţenskih karabataka.Relativne vrednosti mera konformacije nisu bile pod uticajem svetlosnih programa i gustine obroka, osim što je pri manjoj gustini naseljenosti relativna vrednost dubine grudi bila veĆa (P<0.05). Na ošteĆenje tabanskih jastuČiĆa nije utvrčen uticaj svetla i gustine obroka, ali su piliĆi pri veĆim gustinama naseljenosti, poČev od 28. dana, imali znatno veĆa ošteĆenja tabanskih jastuČiĆa nego pri manjoj gustini.Svetlosni program i gustina naseljenosti nisu uticali na fiziČke osobine femura: površinu preseka, silu loma i specifiČnu silu loma. Muški piliĆi imali su veĆi površinu preseka i silu loma femura, razlike za površinu preseka su statistiČki znaČajne, ali ne i za silu loma.Procenat masti u tamnom mesu bio je veĆi, a proteina niţi pri ORS nego pri KS. Ostali parametri hemijske analize tamnog i belog mesa nisu bili pod uticajem svetlosnih programa. Gustina obroka nije imala uticaj na hemijski sastav mesa grudi i karabataka.Na osnovu svega iznesenog moţe se zakljuČiti da su sva tri faktora (svetlosni program, gustina obroka i gustina naseljenosti), kao i njihove interakcije, uticali na brojne proizvodne parametre i kvalitet mesa brojlera, pa i na njihovu dobrobit u razliČitim fazama tova. ImajuĆi u vidu ogromne razlike u efektima koji se mogu postiĆi pri razliČitim kombinacijama ovih Činilaca, rezultati ovih i sliČnih istraţivanja treba da olakšaju izbor tehnologije koja Će davati najbolje ekonomske efekte u tovu piliĆa. Takoče, tamo gde su rezultati nejasni ili kontradiktorni, treba nastaviti istraţivanja na veĆem broju jedinki i fokusirati se na ekonomski vaţnije proizvodne i klaniČne osobine piliĆa.
The purpose of the research was to investigate the effect of the lighting program (constant – KS and intermittent – ORS), feed density and stocking density and their interaction with production and slaughterhouse characteristics of broiler chicken, meat quality and feet pad damage.The research was conducted on a chicken farm Donji Crnci in the vicinity of Podgorica, in three trials: the first trial focused on effects of the lighting program and feed density, the second on the lighting program and stocking density and the third on the lighting program and the feed density (mixes with standard and increased content of energy and protein, with a constant energy:protein ratio). Each of the trials included 320 chicken of the Cobb 500 hybrid line, mixed sexes; trials lasted for 42 days. In all three trials, four groups were formed with four repetitions and each group included 80 one-day chickens.Production parameters (weight, feed consumption and deaths) were monitored in all trials and feed conversion ratio and production index were calculated. Weight was measured when broilers were 1; 7; 14; 21; 28; 35 and 42 days old. Feed consumption was determined at the end of the use of specific mixes, as follows: 14th day the quantity of starter mix consumed, 35th day the quantity of grower mix consumed and 42nd day quantity of the finisher mix. Mortality rate was determined by recording the number of chicken that died during the trial. Production indices were calculated based on weight, food conversion ratio and mortality.At the end of all trials, at 6 weeks of age, the chickens were measured individually, group averages were calculated and then by random sampling, 20 chicken were taken from each group (10 males and 10 females) in order to analyse slaughter characteristics. Pre-slaughter fasting lasted for 12 hours. After slaughter and cleaning, the carcasses were cooled to 40C over 24 hours and then processed as: “classical processing”, “ready to grill” and “barbecue ready”.In carcass processing, abdominal fat was taken out, weight of processed carcases measured and carcass yield values were obtained. In order to determine the yield and share of the main and secondary parts of the carcass, cooled carcasses were cut out. Evaluation of carcass conformation was done on the basis of absolute measures of the following: metatarsus length, keel length, breast depth and drumsticks circumference. Index representing the ratio of live weight before slaughter and measure observed was used (g/mm).In Trial II, physical examination of bones was done, on femur, upon separation from the broiler skeleton, and in Trial III moisture content, total fat content, total ash content and total protein of white and red meat was determined on samples of muscle tissue of breasts and thighs of 5 male and 5 female carcasses in each of the treatments (20 in total).The results show that lighting program had no statistically significant effect on final body weight in Trials I and II, while in Trial III, higher weights were recorded in chicken fattened under KS. ORS resulted in slowing down of the growth rate in the first fattening period, and as a result of compensatory growth it had no effect on final weights, except in the third trial. Better food conversion ratio in the period of finisher mix diet was achieved by chicken in Trial I under ORS than those under KS, as well as in starter mix diet in Trial III. Lighting program in Trial II had no effect on food conversion ratio and mortality of chicken. Feed density did not have an effect on final weights, feed conversion, mortality and production index. In chicken fed with meals with higher protein and energy content, higher weight was recorded at the end of the fattening period (P<0.01). Feed density in Trials I and III did not have an effect on feed conversion ratio, mortality and production index. Significantly higher weight was recorded in chicken fattened at the stocking density of 12 animals/m2 (2667.08 g) than at the density of 17 animals/m2 (2435.768g) and differences had statistically high significance. No effect of stocking density was identified in terms of feed conversion, mortality and production index.Factors analysed (light, feed density and stocking population) did not have an effect on carcass yield, but interactions of some of them did. In all the trials, a smaller share of abdominal fat was established under ORS than under KS, but it was not statistically significant. Feed density and stocking density had no effect on abdominal fat content. Higher abdominal fat content in all trials was found in female than in male chicken. The share of breasts is larger under KS than under ORS, but differences are statistically significant only in the Trial III. Feed density and stocking density had no effect on the share of breasts in the carcass. The share of drumsticks was higher in chicken fattened under ORS than those under KS, but differences were statistically significant only in the Trial I. The share of thighs in Trials I and II did not differ significantly between lighting programs, while in the Trial III it was higher under ORS than under KS (P<0.01). Effect of stocking density and feed density on the share of drumsticks and thighs was not determined. Higher share of drumsticks was determined in male chicken while in female, the share of thighs was higher.Relative values of conformation measures were not influenced by the light programs and feed density, except that in lower stocking density the relative value of the breast depth was higher (P<0.05). Effect of light and feed density on feet pads damage was not determined, but chicken in higher stocking density, as of 28th day, had significantly higher feet pad damage than those in lower stocking density.Light program and stocking density did not have an effect on physical properties of femur: cross-sectional area, breaking force and specific breaking force. Male chicken had larger cross-sectional area and femur breaking force, differences in cross-sectional area were statistically significant, but this was not the case with the breaking force.Percentage of fat in dark meat was higher and that of proteins lower under ORS than under KS. Other parameters of the chemical analysis of dark and white meat were not under the influence of the light programs. Feed density had no effect on chemical composition of breasts and thighs meat.Based on all stated above, it can be concluded that all three factors (light program, feed density and stocking density) as well as their interactions had effect on numerous production parameters and quality of broiler meat, including on their welfare in different fattening phases. Taking into account enormous differences in effects that may be achieved in different combinations of these factors, the results of these and similar researches should make easier the selection of the technology that would yield the best economic effects in chicken fattening. Furthermore, where results are unclear or contradictory, further research should be conducted on a larger number of animals and focus on economically more significant production and slaughterhouse characteristics of chicken.

碩士
國立中央大學
光電科學與工程學系
106
As the plant factory's appeal is to replace natural light with artificial light sources, the plants are moved from outdoor to indoor, so that the growth of plants is not affected by environmental changes. With the LED prices falling and technological advancement, the application of LEDs in plant factories began to appear, LED plants Grow lamps have the advantages of small size, light weight, long life, no heat radiation, and adjustable wavelength of light, so that LEDs are favored by multi-stage cultivation plant factories. The purpose of this study is to conduct in-depth research on indoor planting of LED plant growth lamps. Planting indoor plants can prevent plants from being affected by external environmental climate anomalies. It can also accelerate plant growth and make plants grow better to prevent the food crisis occurred.

The annual number of injuries and fatalities from lightning has, over the last century, been on a steady decline. This is primarily due to urbanisation and movement away from agriculturally intensive activities. In countries with a high urban population, the incidence of lightning fatalities is below 1 death per million people per year. However, in countries with a larger rural population, this rate is signi cantly higher, ranging between 8 and 15 deaths per million people per year. There has been a large drive towards educating the general public about the dangers of lightning and methods to avoid being in a dangerous situation. However, fatal lightning events still occur on a regular basis. There are currently no methods to determine the risk of lightning to living beings in open spaces. The international standard (IEC 62305-2) provides a method for the assessment of risk to living beings within a structure, and up to three metres outside of it. Considering that the majority of deaths by lightning occur outdoors, a method of determining these risks is necessary. The Action Volume Ratio (AVR) is proposed as a new method for the analysis of the danger of lightning in any volume. It considers the dangers of all lightning injury mechanisms in relation to the objects in the space, which are assumed to be the preferential points of strike. A union of the dangerous volumes is then formed, and a ratio to the total volume is created. The AVR uses accepted electrical engineering equations to determine the dangerous areas, and places no reliance on probability theory, which can, in many cases, skew the results of a lightning risk analysis process. The AVR can be combined with lightning ground flash density data to indicate the incidence and frequency of dangerous events within a given volume.

Whistlers are naturally occurring Very Low Frequency (VLF) phenomena which are the result of lightning-radiated electromagnetic waves propagating in Earth’s plasma environment. Major research into whistlers and their generation began in 1951 and since then much has been discovered about them. This has allowed whistlers to be used as magnetospheric probes. Many issues concerning whistlers are still disputed, however, such as the relationship between the lightning location and the conjugate point of the receiver. A correlation between whistlers detected by the DEMETER satellite above South Africa and lightning located by WWLLN was used to determine the source region for these whistlers. The whistlers were found to originate from lightning strokes as far away as 10000 km. This result is statistically significant. During the course of this research an interesting observation of chorus was made on Marion Island. Since this was the first observation of chorus made on the sub-antarctic Marion Island, conditions surrounding the event were studied in great detail. This led to several interesting observations about the nature of this observation. In particular, during the evolution of the emission, it transformed to hiss, which makes this observation relevant to recent results suggesting that hiss is generated by chorus. It was also found that Marion Island was close to the plasmapause during the observation, which has further implications related to the chorus-hiss relationship. A study of the occurrence of twin whistlers received at Rothera and SANAE IV was conducted. These were whistlers which had propagated from a single ionospheric exit point to both receivers. Rothera and SANAE IV share the same whistler source region, yet the average number of whistlers received at Rothera is an order of magnitude greater than that received at SANAE IV. The twin whistler analysis showed that the most probable reason for this disparity is that whistlers from the source region enter the waveguide preferentially closer to Rothera, making it more likely for them to be received at Rothera than SANAE IV. These results have implications on the nature of sub-ionospheric propagation of whistlers, which is not the same as that of spherics. Finally, a method for tracking tropical cyclones using lightning locations from WWLLN was developed. During the course of this thesis, tropical cyclone Irena was the result of damage on the east coast of South Africa. This presented an opportunity to investigate the ability of WWLLN data to describe the passage of these destructive phenomena near South Africa. The details of this new method are discussed. While the algorithm developed has room for improvement, its performance was tested on the recent tropical cyclone Irina which occurred during 2012.
Thesis (Ph.D.)-University of KwaZulu-Natal, Westville, 2012.

The high power, broadband very low frequency (VLF, 3--30 kHz) and extremely low frequency (ELF, 3--3000 Hz) electromagnetic waves generated by lightning discharges and propagating in the Earth-ionosphere waveguide can be used to measure the average electron density profile of the lower ionosphere (D region) across the wave propagation path due to several reflections by the upper boundary (lower ionosphere) of the waveguide. This capability makes it possible to frequently and even continuously monitor the D region electron density profile variations over geographically large regions, which are measurements that are essentially impossible by other means. These guided waves, usually called atmospherics (or sferics for short), are recorded by our sensors located near Duke University. The purpose of this work is to develop and implement algorithms to derive the variations of D region electron density profile which is modeled by two parameters (one is height and another is sharpness), by comparing the recorded sferic spectra to a series of model simulated sferic spectra from using a finite difference time domain (FDTD) code.

In order to understand the time scales, magnitudes and sources for the midlatitude nighttime D region variations, we analyzed the sferic data of July and August 2005, and extracted both the height and sharpness of the D region electron density profile. The heights show large temporal variations of several kilometers on some nights and the relatively stable behavior on others. Statistical calculations indicate that the hourly average heights during the two months range between 82.0 km and 87.2 km with a mean value of 84.9 km and a standard deviation of 1.1 km. We also observed spatial variations of height as large as 2.0 km over 5 degrees latitudes on some nights, and no spatial variation on others. In addition, the measured height variations exhibited close correlations with local lightning occurrence rate on some nights but no correlation with local lightning or displaced lightning on others. The nighttime profile sharpness during 2.5 hours in two different nights was calculated, and the results were compared to the equivalent sharpness derived from International Reference Ionosphere (IRI) models. Both the absolute values and variation trends in IRI models are different from those in broadband measurements.

Based on sferic data similar to those for nighttime, we also measured the daytime D region electron density profile variations in July and August 2005 near Duke University. As expected, the solar radiation is the dominant but not the only determinant source for the daytime D region profile height temporal variations. The observed quiet time heights showed close correlations with solar zenith angle changes but unexpected spatial variations not linked to the solar zenith angle were also observed on some days, with 15% of days exhibiting regional differences larger than 0.5 km. During the solar flare, the induced height change was approximately proportional to the logarithm of the X-ray fluxes. During the rising and decaying phases of the solar flare, the height changes correlated more consistently with the short (wavelength 0.5-4 Å), rather than the long (wavelength 1-8 Å) X-ray flux changes. The daytime profile sharpness during morning, noontime and afternoon periods in three different days and for the solar zenith angle range 20 to 75 degrees was calculated. These broadband measured results were compared to narrowband VLF measurements, IRI models and Faraday rotation base IRI models (called FIRI). The estimated sharpness from all these sources was more consistent when the solar zenith angle was small than when it was large.

By applying the nighttime and daytime measurement techniques, we also derived the D region variations during sunrise and sunset periods. The measurements showed that both the electron density profile height and sharpness decrease during the sunrise period while increase during the sunset period.

Dissertation

碩士
國立中央大學
太空科學研究所
98
Abstract The annually and seasonally averaged distributions of the lightening activity from TRMM/LIS and MicroLab-1/OTD observations all show that the lightening phenomenon most often occurred in the Africa region. This thesis investigates the relation between the lightening phenomenon and the ionospheric scintillation phenomenon in this region by analyzing the TRMM/LIS lightning images and FORMOSAT-3 scnLv1 data. We use amplitude scintillation index S4 data provided by FORMOSAT-3 to indicate the intensity level of the scintillation events and the radiance data provided by TRMM/LIS to reflect the intensity level of the lightening phenomenon. By analyzing the temporal and spatial variations of scintillation, we found that the local time (LT) distribution of scintillation resembles to that of ionospheric F-region irregularities. They both occur at sunset to midnight hours. The seasonal changes of scintillation distribution agree well with those of F-region irregularity. This is consistent with the mechanism that the post sunset irregularities occur favorably in the region where the angel between magnetic declination and sunset line is small. These favorable conditions imply that the scintillation events concentrate in the central Pacific longitude sector along the magnetic equator in the northern summer, while the events concentrate in the Atlantic longitude sector in the northern winter. However, we notice that the scintillation events found in Africa and its vicinities adjacent to the Atlantic Ocean during the northern summer can not be explained by the above mentioned mechanism. Moreover, the analysis of the seasonal variation of scintillation and lightning in Africa reveals that both scintillation and lightning move in the range of ±30° geographic latitudes depending on the seasons. Therefore we suggest that the lightning activity can be the triggering source of the scintillations observed in the Africa coastal region along the Atlantic Ocean. Finally, from quantitative analyses of the nearly simultaneous scintillation data and the TRMM/LIS lightning data for this region, we find that before observing strong scintillations by FORMOSAT-3, the TRMM/LIS did observe strong lightning phenomenon at neighboring locations, and the lightning radiance is greater than the average observed value of lightning intensity. Based on these results, the electric fields associated with the lightning processes at this region may well cause the scintillation phenomenon.