Experimental verification of a zero-dimensional model of the ionization kinetics of XeCl discharges

An improved 0-dimensional model for XeCl high-pressure glow discharges is presented. Calculated discharge voltages are compared with precise measurements at a small, very homogeneous discharge. Excellent agreement in a wide parameter field demonstrates that this model may serve as a reference for simpler models describing the ionization kinetics

Small volume coaxial discharge as precision testbed for 0D-models of XeCl lasers

In order to check the predictions of 0D-models experimentally, a small coaxial discharge configuration for the generation of homogeneous high pressure glow discharges (diameter 11 mm, length 20 mm) in rare gas halogen excimer laser gas mixtures under accurately controlled conditions has been developed. It uses X-ray preionization and a special pulse-forming network (PFN) delivering fast rising (8 ns) single square pulses (U 0=25 kV; I=300 A; prop=100 ns). Discharge current and voltage are measured precisely by a capacitive voltage divider and a shunt integrated into the discharge chamber. All circuit data needed for the model calculations have been evaluated. Interferometric and spectroscopic diagnostics of the bulk of the discharge and of the cathode sheath have been performed. First results for Ne/Xe/HCl mixtures are compared with model calculations

Negotiated matter: a robotic exploration of craft-driven innovation

This paper introduces a novel approach to craft-driven robotic innovation in architectural research. Here craft is not portrayed as a source of ornamental or historical inspiration, but instead as an open-ended process described by a framework involving material properties, diverging modes of knowledge production and representation, emergent tectonic configurations and embodied interaction with technology. To do so, this paper firstly contrasts a definition of craft (Pye 1968) with practices of robotic architectural production. Additionally, the notion of emergent tectonics resulting from negotiated material and technological processes is addressed by critically situating the theories of architectural tectonics by Kenneth Frampton (2001) and digital tectonics by Leach, Turnbull and Williams (2004) in the context of robotic fabrication in architecture. Finally, the ongoing project “Computing Craft” is presented as a case study illustrating a proposed framework for robotic craft-driven innovation

Time Budget of Employed Housewives

The occupational and familial situation and the course of the day of employed housewives in the FRG. Topics: Detailed information on time budget on working days as well as on weekends; time used for various activities in household; help of spouse and children in housework; shopping habits; commuting time to job; carrying out certain housework on the weekend; additional burdens from care of older persons or persons continually sick; time expended for the children; preferred housework and leisure activities; personal training in housekeeping and child care; enhancement of the knowledge in home economics during marriage; attitude to a personal occupation as childminder and willingness to turn over one´s own child to a childminder; length and reasons for personal employment; general contentment with life; contact with doctors and hospital stays; health complaints; work satisfaction as housewife; housing situation and housing conditions; type of heating and location of residence; technical features of residence. Demography: city size; marriage duration; age und number of children; age (classified); school education; occupation; employment; income; size of household; composition of household; social class; possession of durable economic goods.Die berufliche und familiale Situation und der Tagesablauf von erwerbstätigen Hausfrauen in der BRD. Themen: Detaillierte Angaben zum Zeitbudget an Werktagen sowie an Wochenenden; zeitliche Inanspruchnahme für verschiedene Tätigkeiten im Haushalt; Hilfe des Ehepartners und der Kinder bei der Hausarbeit; Einkaufsgewohnheiten; Wegezeit zum Arbeitsplatz; Erledigung bestimmter Hausarbeiten am Wochenende; zusätzliche Belastungen durch Pflege älterer bzw. ständig kranker Personen; Zeitaufwand für die Kinder; präferierte Hausarbeiten und Freizeitbeschäftigungen; eigene Ausbildung in Haushaltsführung und Kinderpflege; Erweiterung der Kenntnisse in Hauswirtschaft während der Ehe; Einstellung zu einer eigenen Tätigkeit als Tagesmutter und Bereitschaft zur Überlassung des eigenen Kindes bei einer Tagesmutter; Dauer und Gründe der eigenen Berufstätigkeit; allgemeine Lebenszufriedenheit; Arztkontakt und Krankenhausaufenthalte; gesundheitliche Beschwerden; Arbeitszufriedenheit als Hausfrau; Wohnsituation und Wohnverhältnisse; Art der Heizung und Lage der Wohnung; technische Ausstattung der Wohnung. Demographie: Ortsgröße; Ehedauer; Alter und Anzahl der Kinder; Alter (klassiert); Schulbildung; Beruf; Berufstätigkeit; Einkommen; Haushaltsgröße; Haushaltszusammensetzung; Schichtzugehörigkeit; Besitz langlebiger Wirtschaftsgüter

Ionisationsmechanismus in der Relaxationszone schwach instationärer Stoßwellen in Argon und Krypton

The primary ionisation relaxation up to electron densities of ne = 4·1013 cm-3 is investigated by means of 4 mm - microwave - interferometry. The values of the timedependent gas temperature Ta, and gas density na behind the shock front are calculated using a gasdynamic model which strictly takes into account the instationarity of the flow. From the results it is concluded that neither the familiar two step process dominated by atom collisions nor the assumption of additional excitation processes by electron collisions can fully describe the observed ionisation rates. There is evidence that both the ionisation rates and the electron temperature are influenced by transitions between the first four excited states due to superelastic electron collisions. As a result the electron temperature may even exceed the gas temperature

Vacuum arc cathode spot parameters from high‐resolution luminosity measurements

Cathode spots on arc‐cleaned copper and molybdenum electrodes in vacuum were studied by fast image converter framing and streak camera photography with high temporal and spatial resolution. The frame exposure time was 20 ns and the interframe period was 200 ns; the streak sweep time was between 200 ns and 1 μs. Spatial structures with a resolution of 5 μm could be determined by observing the spot movement with a small slit at the streak camera and a high sweep speed. Strong fluctuations of the light emission of the spot were found with characteristic times of 50–100 ns. When the spot moved out of the slit field of view a stepwise decrease occurred in the measured light, indicating an internal substructure of the spot with distances between fragments less than 10 μm and even smaller fragment diameters. The current per fragment was estimated to be 20–40 A. The frames confirm the short time constants of the spot. From frame to frame a spot motion was observed in most cases, yielding spot residence times <200 ns

An argon cascade-arc plasma pulsed with 2200 amperes

In the past several authors have reported on experiments with wall stabilized arcs, to study transport coefficients, deviations from local thermodynamic equilibrium (LTE) and optical properties of these thermal plasmas. Most of these experiments have been performed with continuous arcs in a pressure range of atmospheric to a few 100 atm. In order to get high electron densities, temperatures and to reach higher ionization stages, a current pulse of approximately=2200 A is superimposed on a stationary argon cascade-arc with filling pressures of 1-3 atm. In this way high power densities can be reached, without the need of extensive cooling and power requirements. The rise time of the current pulse approximately=60 mu s and duration time approximately=1.5 m