Search for dissertations about: "Lightning"

Showing result 1 - 5 of 59 swedish dissertations containing the word Lightning.

  1. 1. On the Attachment of Lightning Flashes to Grounded Structures

    University dissertation from Uppsala : Acta Universitatis Upsaliensis

    Author : Marley Becerra; Uppsala universitet.; [2008]
    Keywords : Engineering physics; Lightning; Lightning attachment; Positive leader discharges; Lightning protection; Thunderstorms; Numerical modeling; Teknisk fysik;

    Abstract : This thesis deals with the physical modeling of the initiation and propagation of upward positive leader discharges from grounded structures during lightning strikes. It includes the analysis of upward leaders initiated under the influence of the electric field produced by a dominant negative cloud charge and due to the combined action of a negative thundercloud and a descending downward stepped negative leader. READ MORE

  2. 2. Electromagnetic Interference in Distributed Outdoor Electrical Systems, with an Emphasis on Lightning Interaction with Electrified Railway Network

    University dissertation from Uppsala : Institutionen för teknikvetenskaper

    Author : Nelson Theethayi; Uppsala universitet.; [2005]
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; EMC; Lightning; TECHNOLOGY Electrical engineering; electronics and photonics; TEKNIKVETENSKAP Elektroteknik; elektronik och fotonik; Electrical engineering; Electromagnetic Compatibility EMC ; Lightning Protection; Transmission Lines; Electromagnetic Wave Propagation; Underground Cables; Grounding; Electromagnetic Transients; Electromagnetic Interference; Shielding Effectiveness; Railway Systems; Elektroteknik; elektronik och fotonik;

    Abstract : This thesis deals with the electromagnetic compatibility (EMC) problems of distributed electrical networks, especially that caused by lightning to electrified railway. Lightning transients were found to damage important devices that control train movements, causing traffic stoppage and delays. READ MORE

  3. 3. Interaction of Lightning Flashes with Wireless Communication Networks Special Attention to Narrow Bipolar Pulses

    University dissertation from Uppsala : Acta Universitatis Upsaliensis

    Author : Mohd Riduan Ahmad; Uppsala universitet.; [2014]
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Latitude; Lightning; Narrow bipolar pulse; Wireless network.; Engineering Science with specialization in Atmospheric Discharges; Teknisk fysik med inriktning mot atmosfäriska urladdningar;

    Abstract : In this thesis, the features of electric field signatures of narrow bipolar pulses (NBPs) generated by cloud flashes are investigated and their effects on wireless communication systems are studied. A handful amount of NBPs (14.5%) have been observed to occur as part of cloud-to-ground flashes in South Malaysia. READ MORE

  4. 4. Electromagnetic Interference to Electrified Railway Network Caused by Lightning: : Development of Computation Models

    University dissertation from Uppsala : Acta Universitatis Upsaliensis

    Author : Nelson Theethayi; Uppsala universitet.; Uppsala universitet.; [2004]
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Railway EMC; Lightning;

    Abstract : .... READ MORE

  5. 5. Experimental Observations and Theoretical Modeling of Lightning Interaction with Tall Objects

    University dissertation from Stockholm : KTH Royal Institute of Technology

    Author : Helin Zhou; KTH.; [2013]
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Tall objects; Upward lightning initiation; Charge density distribution; Upward positive lightning; Upward bipolar lightning;

    Abstract : This thesis investigates various discharge processes associated with upward lightning initiated from tall objects, both experimentally and theoretically, trying to bridge the knowledge-gap in understanding the mechanisms of the phenomena.Upward lightning initiation has attracted a great deal of interest during recent years due to the proliferation of tall communication towers and wind turbines. READ MORE