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Detection of photospheric zeeman features and cyclotron emission lines in v834 cen in a low state
(1992) Ferrario, Lilia; Wickramasinghe, D. T.; Bailey, Jeremy; Hough, J. H.; Tuohy, I. R.
We report simultaneous spectroscopic and polarimetric observations of the AM Herculis system V834 Cen during a low state of accretion. The polarization data show a reversal in the sign of the circular polarization when A λ ≳ 5000 A which lasts for about 0.1 in phase and which is not present during a high state. The reversal can be interpreted as the result of dominance of photospheric radiation at these phases. The photometric observations show, for the first time, nearly sinusoidal UBV light curves with minima shifted by 0.5 in phase from previous high-state observations. This behaviour is explained by assuming that the radiation in the blue bands is dominated by blackbody emission from the heated photosphere near the accretion region. The spectroscopic observations show broad, resolvable cyclotron harmonics and strong photospheric Zeeman features. Theoretical models suggest the presence of a dipole of polar field strength Bp≈ 31 MG offset by ≈-0.1 Rwd from the centre of the white dwarf along the dipole axis. The cyclotron emission region is located « 10° from the pole and has B≈ 23 MG.
Estimating unmetered stock and domestic water use
(Modelling and Simulation Society of Australia and New Zealand Inc (MSSANZ), 2009-01-01) Lowe, L.; Vardon, M.; Etchells, T.; Malano, H.; Nathan, R.
Water accounts present information on the stores and movement of water, including the volume of water diverted for consumptive use. Water extracted directly by water users to meet their stock and domestic water requirements is not metered in Australia and as a result, estimates are used to quantify this component in the water accounts and for other purposes. Two approaches to estimate the water extracted for stock and domestic purposes are identified: 1. An estimate of the number of households and stock that rely on self extracted water is multiplied by their expected water requirements. 2. The number and volume of stock and domestic licenses issued by the water authorities to divert water from waterways or groundwater is combined with information on the use of farm dams to estimate the stock and domestic water use. This paper compares directly estimates of stock and domestic water use generated by each of these two approaches for the Werribee River catchment (Victoria, Australia) for 2005/06. The two approaches are not expected to generate identical estimates due to the uncertainties associated with each of the estimates. Therefore, the uncertainty surrounding each of the estimates is also quantified and represented with a probability distribution. Ideally these two probability distributions would overlap and thereby show that the two approaches provide consistent results. Data collected by the Australian Bureau of Statistics is used to estimate the number of households (2006 Population census) and stock (2005-06 Agricultural Census) in the catchment. These data are reported by the ABS according to statistical boundaries that do not correspond to the Werribee River catchment, and so had to be adjusted for use in the study, which provides an additional level of uncertainty. The uncertainty associated with expected water requirements of individual households and stock is also considered. The best estimate of the total stock and domestic water use using this first approach is 690 ML, and the 95% confidence interval is equivalent to ±63% of the best estimate. The source of uncertainty that has the largest influence on the results is the number of stock in the catchment, followed by the estimate of the expected water use per head of stock. Using the second approach, extractions from waterways and groundwater sources are assumed to be related to license conditions and be within the limits set by these conditions. As extractions from farm dams are not licensed, estimates are based on simulation modelling. The estimate of stock and domestic water use generated by this second approach is higher, and is 810 ML. The 95% confidence interval surrounding this estimate is equivalent to ±55% of the best estimate. The uncertainty surrounding the volume of groundwater extractions has the largest influence on the overall uncertainty. The estimates of stock and domestic water use generated by the two approaches diverge by 119 ML (or 15% of the upper value), but there is substantial overlap of the 95% confidence intervals associated with each estimate. Which is the better estimate of D&S water use is unclear as the uncertainty surrounding each of the two estimates is similar. As the data needed for the first approach are available for all of Australia on an ongoing basis from the ABS, then the demand approach is probably the most practical approach at present for deriving standardised and comparable estimates of domestic and stock water use across Australia.
Multilayer laser printing for organic thin film transistors
(2011-04-01) Rapp, Ludovic; Nénon, Sébastien; Alloncle, Anne Patricia; Videlot-Ackermann, Christine; Fages, Frédéric; Delaporte, Philippe
Functional laser printed Organic Thin Film Transistors (OTFTs) have been achieved from multilayer substrates composed with semiconductor and electrodes. The p-type copper phthalocyanine (CuPc) was used to form the active layer. Different kinds of metallic materials were used for source and drain electrodes. Multilayer donor substrates were prepared by the successive depositions of materials by either thermal evaporation under vacuum or laser printing. The materials were transferred together in a single step onto a receiver substrate by laser pulses in the picosecond regime. The latter substrate formed the gate and the dielectric of the transistor. The results are compared with the step-by-step laser printing process, where electrodes and organic layer were successively printed from two different donor substrates. The multilayer laser printing reveals an improvement of the performances of the OTFT devices.
Petrology and trace element geochemistry of the Papuan Ultramafic Belt
(1980) Jaques, A. L.; Chappell, B. W.
New petrologic and geochemical data are presented for a suite of rocks from the Papuan Ultramafic Belt (PUB), Papua New Guinea. Tectonite harzburgites at the base of the ophiolite have extremely refractory, uniform mineralogy, and are exceptionally depleted in lithophile elements. These features are consistent with the proposed origin of these rocks as 'depleted' upper mantle, residual after extraction of a basaltic melt. The tectonite peridotites are overlain by a thick sequence of layered ultramafic and mafic cumulates containing olivine, orthopyroxene, clinopyroxene and plagioclase as the major cumulus phases. Early cumulates are characterized by magnesian olivine Mg90, orthopyroxene Mg90 and calcic plagioclase An86, and exhibit cryptic variation towards more iron-rich and sodic compositions. Abundances of 'incompatible' elements in the cumulates are extremely low which, together with the nature of the cumulus phases, points to a magnesian olivine-poor tholeiite or magnesian quartz tholeiite parent magma(s) strongly depleted in 'incompatible' elements. Highly fractionated iron-rich products of this parent magma type are represented by the LREE-depleted lavas in the overlying basalt sequence which, although resembling the most depleted mid-ocean ridge basalts (MORB) in terms of their low abundances of 'incompatible' elements, have higher abundances of transition metals and lower abundances of Ti, HREE and other high valence cations compared to common MORB of similar Mg/(Mg+Fe) ratio. Eocene tonalites intruding the PUB are genetically unrelated to the ophiolites, and appear to be related to the Ti-poor high-Mg andesites of Cape Vogel and similar andesites and dacites at the northern end of the PUB. These rocks are considered to represent the early stages of island-arc magmatism associated with a northeastward-dipping subduction zone in the early Eocene immediately prior to emplacement of the PUB.
The diamond-bearing ultrapotassic (lamproitic) rocks of the West Kimberley region, Western Australia.
(1984) Jaques, A. L.; Lewis, J. D.; Smith, C. B.; Gregory, G. P.; Ferguson, J.; Chappell, B. W.; McCulloch, M. T.
These lamproitic rocks are of Miocene age (20 m.y.) and comprise more than 100 separate pipes, plugs, sills and rare dykes. The recently-discovered 'kimberlitic' rocks - olivine lamproites - grade petrographically through leucite-bearing olivine-diopside lamproite to the better-known leucite lamproites with phlogopite, diopside and potassic richterite as the dominant ferromagnesian phase. The lamproites range from ultrabasic (20-29% MgO) to basic (= or <5%) compositions: all have very high K2O contents (4-12%) and high K2O/Al2O3 (average 1.2) and K2O/Na2O (typically >10) ratios. All are saturated to oversaturated in silica, and SiO2 and Al2O3 contents increase with decreasing MgO content and Mg/(Mg + Fe) ratio. The suite is characterized by very high contents of F, Ba, Rb, Sr, Pb, Th, U, Ti, Zr, Nb and LREE, and very low concentrations of CaO, CO2 and Sc. REE patterns are highly fractionated and enriched in LREE at 500-2000X chondritic abundances with very low abundances of HREE (4-6X chondritic). The Rb/Sr and 87Sr/86Sr ratios are high (0.3-0.4, 0.711-0.720) and 143Nd/144Nd ratios very low (epsilonNd -7 to -15), indicating derivation from an ancient, LILE-enriched mantle source.-J.M.H.