The lightning is the natural source of electromagnetic radiation. It is an atmospheric electrical discharge.  However, since recent times, it was discovered that there are other types of lightning besides those that are visible to the naked eye. They are called TLEs (Transient Luminous Event) and take place above the clouds during thunderstorms. Distinct classification is applied to the various existing TLEs in compliance with their shapes, size, color, altitude, origin and duration. Thus, all Transient Luminous Events are categorized to the following types: elves, spites, halos, blue jets, blue starters, gigantic jets, trolls, gnomes, pixies and ghosts. TLE investigation missions are important for several scientific purposes. They allow to gain an understanding of the lightning creation processes, contribution on global electric circuits as well as chemical influence on the Earth’s climate.  TLE observations can be performed by lightning detection and location systems which differs according to their location. They can be ground-based, space-based as well as carried on aircraft or balloon. Lightning location systems in space are usually conducted on large-, medium- or micro-sized satellites.  The main scope of this thesis is to explore and describe all possible and known methods and techniques of TLE investigation as well as discussions of gained observation results for better understanding and further analysis of more suitable instruments for TLE detection mission on LEO orbit. Analysis of suitable equipment will be done according to the conclusion made from considered lightning detection systems with similar missions and pursuant to nanosatellite requirements.

International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / This student paper was produced as part of the team design competition in the University of Arizona course ECE 485, Radiowaves and Telemetry. It presents a telemetering system proposed for UASat, a small satellite being designed for launch in the year 2004. The overall system architecture is described, including the transducers used by each subsystem, the command and telemetry packet formats, the antennas and modulation schemes, the link budget, and some hardware recommendations. A discussion of the data analysis is also included.

What are the origins of tactical innovation in large, bureaucratic, military systems? This study will provide a detailed analysis of how the German Army in World War One took advantage of innovative tactical methods developed by their junior and non-commissioned officers in the field. While many historians often look at the results of WWI from the perspective of the General officers and politicians (i.e., top-down), they often overlook the important roles played by creative junior officers in revolutionizing the manner in which the German Army fought. These innovations, when supported by senior leadership, led to massive operational and strategic gains for the German Army late in World War One. I will explore how the German Army successfully applied these tactical innovations at the Twelfth Battle of the Isonzo, a.k.a. The Battle of Caporetto in 1917. The result was a crushing Italian defeat. This success encouraged the German leadership to attempt similar offensives in 1918 on the Western Front in France. Initially successful, the offensives later stalled. However, the lessons of these attacks formed the basis for what would become universally known as the Blitzkrieg, or â lighting-warâ tactics. These lessons continue to effect how modern militaries employ combined arms in maneuver warfare today. This case study will highlight the importance of â bottom-upâ tactical innovation within todayâ s U.S. military.

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

Thesis (M.Sc.), Faculty of Engineering (Electrical Engineering), University of the Witwatersrand, 1994

A dissertation submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, in ful lment of the requirements for the degree of Master of Science in Engineering. Johannesburg, 2015 / During a cloud to ground lightning event a charge centre within the storm cloud is discharged. The discharge of a charge centre within the cloud leads to a change in the electric eld radiated by the charge centre. It is theoretically possible to infer the lightning current from the derivative of the electric eld. It is only possible to infer the lightning current from the electric eld data where the noise is comparatively much smaller than the electric eld data. The changing electric elds for a lightning event that occurred on the 3rd January 2015 13:15:13 were recorded by a at plate electric eld sensor with a passive integrator. The oscilloscope used to capture the electric eld data has a relatively large measurement noise and a low resolution. A low pass digital lter was applied to the recorded electric eld data to reduce the e ects from the high frequency noise. The lightning strokes were recorded by the South African Lightning Detection Network. The Lightning Detection Network data is used to obtain the distance of the lightning event from the sensor, to scale the inferred lightning current. The Lightning Detection Network also provides a lightning peak current measurement to compare to the peak current inferred from the electric eld data. The lightning stroke current was inferred from the electric eld recording for various bandwidths of the low pass lter. Inconsistent changes to the inferred lightning stroke current as the lter bandwidth is changed shows that the frequency components for each stroke di ers. The peak stroke current was not constant for any lter bandwidth range implying that the measurement noise is relatively too large. The case study presented demonstrates that with a relatively large noise magnitude (3 to 4 discrete steps of the digital recording) compared to the electric eld signal (21 discrete steps) it is di cult to accurately infer the lightning current from the electric elds recorded. / MT2017

Student Number : 0418388R - MSc(Eng) research report - School of Electrical and Information Engineering - Faculty of Engineering and the Built Environment / Due to the high soil resistivities and high frequency of lightning strikes in South Africa, the background theory about the effect of soil resistivity on the LV surge environment is important, but the present local and international standards do not give reasonable explanations for this effect. The previously published experimental results and research results related to this effect were investigated. From these investigations, it can be shown that the soil resistivity can affect surge generation, surge propagation and surge attenuation significantly. Also, soil resistivity plays a main role in the lightning surges caused by both direct strikes and indirect strikes, which can cause severe damage to the LV distribution system. Soil resistivity also has a significant impact on the resistance of an earth electrode.

Abstract With an ever increasing emphasis on reliability of supply, improvement in the lightning performance of distribution lines is required. The arc quenching properties of wooden distribution line poles during lightning strikes are an important factor in the reduction of switchgear operation, hence outages. Measurements were conducted on a 22 kV distribution line and it was suspected, in some cases, that direct lightning strikes to the line did not cause switchgear operation. Distribution lines predominantly use wooden poles with a specific configuration which incorporates a 'wooden' spark gap. This paper provides background to the basic configuration of a typical distribution line and the processes which govern the electric arc. A simulation using a dynamic arc model shows that field measured lightning overvoltages on a distribution line are reproducible through system modelling. The simplistic dynamic arc model developed is sufficiently accurate to describe a set of arcs in a larger system such as a distribution line.

Orientador: Luís Rogério de Oliveira Hein / Coorientador: Prof. Dr. Milton Eiji Kayama / Banca: Mauricio Antonio Algatti / Banca: Steven Frederick Durrant / Resumo: 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 ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: 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 / Mestre

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