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Ohne Zusammenfassung     

Surface charge accumulation and decay on a spacer stressed with DC voltages at atmospheric conditions

Contents Surface charge accumulation and its decay at a GIS spacer are studied at atmospheric conditions employing a two step-calibration method. The results show that the accumulation saturates within 30 minutes; the dominant mechanism of surface charge accumulation is the drift of charged particles via air, while that of the decay is surface conduction. The characteristics are similar at both polarities.

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Sättigungskonzentration und Abklingverhalten der Oberflächenladung an einem mit Gleichspannung beanspruchten Abstandshalter unter atmosphärischen Bedingungen

Übersicht Die Konzentration und das Abklingen von Oberflächenladungen an einem GIS Abstandshalter wurden unter atmosphärischen Bedingungen mit Hilfe eines zweistufigen Kalibrierungsverfahrens untersucht. Die Ergebnisse zeigen eine Sättigung der Ladungskonzentration innerhalb von 30 Minuten. Als Hauptursache der Ladungskonzentration ist die Drift geladener Teilchen in Luft anzusehen, während das Abklingen auf die Oberflächenleitung zurückzuführen ist. Ähnliche Charakteristiken ergeben sich mit beiden Polaritäten.

     

A Study of Ozone Generation by Negative Corona Discharge Through Different Plasma Chemistry Models

The Steady radial distribution of chemical species in a wire‐to‐cylinder ozone generator filled with pure oxygen has been computed by applying four different plasma chemistry models of increasing complexity. The most complete model considers ten species (e, O₂ ⁺, O₂ ^?, O₃ ^?, O^?, O₂, O₂(¹Δ_g), O₂(¹∑_g ⁺), O and O₃) and 79 reactions, including ionization by electron impact, electron attachment and detachment, electron-ion recombination, charge transfer, etc. The chemical model is coupled with the electrical model through Poisson's equation. The spatially averaged ozone density has been computed as a function of the current intensity and compared with the experimental values obtained by UV spectroscopy.     

Smart help for operator performance

Our emphasis in this paper has been on the knowledge-based and cognitive issues pertinent for improved interactions between workers and manufacturing computer systems. We believe that these techniques are as necessary and applicable to manufacturing as to any other vocation, especially as the difference in collar color of shop people becomes less noticeable in their increasing role as knowledge workers.     

A systematic transition to flexible manufacturing

The transition from basic automation to flexible manufacturing is an expensive and tedious procedure. It requires meticulous planning and almost clairvoyant forecasting to insure that the initial flexibility obtained is sufficient to allow growth and expansion in the future. This paper will suggest a systematic and methodological approach to achieve optimal flexibility and describe the present results of its application to an ongoing system transformation.

Conclusions based on existing levels of completion are presented along with identification of critical and non critical flexibility requirements. The considerations and steps taken are summarized in a procedural format which may then be applied to a wide variety of system transformations.