Sökning: "Teknisk fysik med inriktning mot atmosfäriska urladdningar"

Visar resultat 1 - 5 av 9 avhandlingar innehållade orden Teknisk fysik med inriktning mot atmosfäriska urladdningar.

  1. 1. Broadband and HF Radiation from Cloud Flashes and Narrow Bipolar Pulses

    Författare :Noor Azlinda Ahmad; Vernon Cooray; Farhad Rachidi; Uppsala universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Lightning; Cloud Flashes; Narrow Bipolar Pulses; HF radiation; Other physics; Övrig fysik; Engineering Science with specialization in Atmospheric Discharges; Teknisk fysik med inriktning mot atmosfäriska urladdningar;

    Sammanfattning : Remote measurement of electric field generated by lightning has played a major role in understanding the lightning phenomenon. Even though other measurements such as photographic and channel base current have contributed to this research field, due to practical reasons remote measurements of electric field is considered as the most useful tool in lightning research. LÄS MER

  2. 2. Positive streamer discharges in air and along insulating surfaces: experiment and simulation

    Författare :Mose Akyuz; Fridolin Heidler; Uppsala universitet; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; Engineering physics; Teknisk fysik; Engineering physics; Teknisk fysik; teknisk fysik med inriktning mot atmosfäriska urladdningar; Engineering Physics; with a direction to Atmospheric Discharges;

    Sammanfattning : The power quality of modern society relies on the electrical properties of the dielectric insulators used in the power industry. Much research work has been conducted with an aim to understand and predict the insulating behaviour of such materials under different kinds of atmospheric conditions, but still there are many unsolved problems. LÄS MER

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

    Författare :Mohd Riduan Ahmad; Vernon Cooray; Mahbubur Rahman; Rajeev Thottappillil; Uppsala universitet; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; TEKNIK OCH TEKNOLOGIER; NATURAL SCIENCES; ENGINEERING AND TECHNOLOGY; Latitude; Lightning; Narrow bipolar pulse; Wireless network.; Engineering Science with specialization in Atmospheric Discharges; Teknisk fysik med inriktning mot atmosfäriska urladdningar;

    Sammanfattning : 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. LÄS MER

  4. 4. Numerical Simulations of Long Spark and Lightning Attachment

    Författare :Liliana Arevalo; Vernon Cooray; Dan Windmar; Uppsala universitet; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; breakdown; discharge; leader channel; lightning attachment; negative discharge; positive discharge; streamer; Electrical engineering; Elektroteknik; Engineering Science with specialization in Atmospheric Discharges; Teknisk fysik med inriktning mot atmosfäriska urladdningar;

    Sammanfattning : The research work presented here is concerned with numerical simulations of two different electrical phenomena: Long gap electrical discharges under switching impulses and the lightning attachment process associated with positive upward leaders. The development of positive upward leaders and the progression of discharges in long gaps are attributable to two intertwined physical phenomena, namely, the leader channel and the streamer zone. LÄS MER

  5. 5. Characterizations of ground flashes from tropic to northern region

    Författare :Zikri Abadi Baharudin; Vernon Cooray; Mahbubur Rahman; Farhad Rachidi; Uppsala universitet; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Positive negative cloud-to-ground lightning flashes; Initiation position; slow field changes; close ground flashes; preliminary breakdown process; Engineering Science with specialization in Atmospheric Discharges; Teknisk fysik med inriktning mot atmosfäriska urladdningar;

    Sammanfattning : This thesis portrays new information concerning the cloud-to-ground (CG) lightning flashes or ground flashes produced by thunderclouds. It emphasizes the importance of characterizing lightning studies as the relationship between lightning mechanisms, and of incorporating the influence of geographical location, latitude and storm type. LÄS MER