546 research outputs found

    A diagnostic study of two dimensional deep convection using a numerical model

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    Imperial Users onl

    Magnetic Flux Braiding: Force-Free Equilibria and Current Sheets

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    We use a numerical nonlinear multigrid magnetic relaxation technique to investigate the generation of current sheets in three-dimensional magnetic flux braiding experiments. We are able to catalogue the relaxed nonlinear force-free equilibria resulting from the application of deformations to an initially undisturbed region of plasma containing a uniform, vertical magnetic field. The deformations are manifested by imposing motions on the bounding planes to which the magnetic field is anchored. Once imposed the new distribution of magnetic footpoints are then taken to be fixed, so that the rest of the plasma must then relax to a new equilibrium configuration. For the class of footpoint motions we have examined, we find that singular and nonsingular equilibria can be generated. By singular we mean that within the limits imposed by numerical resolution we find that there is no convergence to a well-defined equilibrium as the number of grid points in the numerical domain is increased. These singular equilibria contain current "sheets" of ever-increasing current intensity and decreasing width; they occur when the footpoint motions exceed a certain threshold, and must include both twist and shear to be effective. On the basis of these results we contend that flux braiding will indeed result in significant current generation. We discuss the implications of our results for coronal heating.Comment: 13 pages, 12 figure

    Phosphorus and sulphur group

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    Long Term Trials Stocking and superphosphate trials - 66M30, 68BR7. Maintenance Phosphorus x Sulphur trials - 65A1, 65N5, 65C5, 69WH15, 68B1, 69AL3 and 67N05. Low Rainfall Crops and Pastures. Residual phosphorus trials - 76ES8, 75KA4, 75LG26 and 76NA5. Miscellaneous Cropping Trials. Rate of phosphorus on wheat - 77ES2, 77ME5, 77N03. N. P and seed rates on wheat - 77JE1. Row spacing, phosphorus and seed rate on wheat - 77ME6. Phosphorus on nitrogen build up - 77M033. Rate of super on old land lupins - 77A18 & 19, 77BA13 & 14, 77E20. Pasture Trials. Phosphorus and Sulphur on old land pasture - 77BA 17, 18, 19, 20, 21 , 22, 23 and 24. High Rainfall Pasture Trials. Current and residual phosphorus - 75AL5, 75DE5, 75DE7, 75BR13, 76BU13(a), 76KE10 and 76MA2. Phosphorus and Sulphur 1977 Phosphorus Soil Test Series - 77AL5, 77AL6, 77HA10, 77DE6 & 7, 77BR14, 15, 16, 17, 18 & 19, 77BU6 & 7, 77BY3

    General phosphorus and sulphur trials

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    (A) Long Term Trials/Trial number: Super x Stocking Rate - 66M30. Super Sulphur and Stocking Rate - 68BR7. Maintenance P and S trials - 69E6, 68B1, 65A1, 65N5, 65C5, 69WH15 & 67N05. Continuous Cropping - 75LG26. Cropping Residual Value - 29M/148, 149. (B) Lupin Trials: Rate of P and S - 78A8, 78A9, 78BA9, 78BA10, 78C5, 78C6, 78E8, 78E9, 78WH7, 78WH8 & 78NA25. Current and Residual phosphorus - 75KA4. (C) Cereal Trials: Depth of Placement of P on Wheat - 78M38. Row spacing x P rates on Wheat - 78ME4. Current and Residual Nitrogen on Wheat - 77M033. (D) Pasture Trials: Times of application - 77BA38. Residual value - 77BA21, 78BA7, 77BA22, 77BA24, 78M010. Rates of Phosphorus - 78M011. P and S on irrigated pastures - 77HA10

    Phosphorus and sulphur interactions, 1978.

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    Yield results, 78AL3, 78KE4, 78M08, 78BY3, 78BA8, 78BU3, 78N04, 78A7, 78C4, 78B4, 78MA2. Soil sampling data

    The effect of calcium aluminates on the coke analogue gasification

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    The gasification rate in CO2 of the coke analogue containing calcium oxide was studied using analogues doped with alumina (corundum), calcium aluminates (CA6, CA, C3A) and lime minerals. The coke analogue is a laboratory material with simplified carbon structure that has a mineral component with a particle size, size distribution and mineral dispersion that can be controlled. The main focus of this study was to quantitatively assess the effect of calcium in the mineral on the analogue’s reactivity. The analogues were reacted with CO2 isothermally in the temperature range of 1173–1623 K. It was found that the reaction rate increased with increasing CaO activity/number of moles of Ca in the mineral. The relative reaction rates (from lowest to highest) of the analogues doped were alumina, CA6, CA, C3A and lime. The relative apparent activation energies of the gasification from lowest to highest was lime, C3A, CA, CA6 and alumina

    SUMMARY OF EXPERIMENTAL RESULTS 1979 GENERAL PHOSPHOROUS TRIALS

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    Contiuing trials Stock rate and level of Superhosphate on cyprus medic pasture 66M30 Rates of phosphorus, sulphur and stocking trial - cropping phase 68BR7 Maintenance P x S trials 65N5, 69WH15, 65A1, 65c6 Residual Value of Phosphorus 78M08, 78C4, 78MA2, 75LG26, 78M38 NEW TRIALS Crops N x P Trials 79NA11, 79NA12, 79NA13 Times of P on Lupins 79M030 Lupin and Oat Mixtures 79BA31, 79MT30 Methods Application and Cultivation of P on Wheat 79M1, 79WH1 Methods and Times of P on Wheat Old Land 79N1 Rates of Super on Wheat 79LG Rates of Super on Lupins 79GE PASTURES Rates of P, K and S on Pasture - Dandaragan 79M012, 79M013, 79M015, 79M017 Rates of P, K and S on Pasture – Lancelin 79M011, 79M018 Rates of P on Pasture – Newdegate 79N5, 79N6 Rates of P x Species on Pasture 79N05, 79JE

    Super and stocking rates at Kojonup after 10 years

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    A Department of Agriculture trial on old land at Kojonup has been comparing rates of superphosphate and stocking of sheep for 10 years

    1976 Phosphorus and sulphur group

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    Stocking x Super. rate trials - 66M30, 62MB9, 68BR7. Crossed plot trials - residual value. P x K on Pasture - 74TS4, 74M06, 75GE6. N x P on· Wheat - 75M09. P x Species - 75LG4, 75JE5. Maintenance P x S trials - Wheat Belt Research Station - 65A1; C5, N5, 69WH15. High Rainfall Areas - 68B1, 69E6, 69AL2. Farmers residual value - 66N07, 66ME3,67N011, 66NA3, 66LG1, 68LG1, 66M06, 67M01, 67GE2, 67N05, 67N04, 66N09. Miscellaneous Cropping Trials - Super x Spacing - 76ME26, 76ES8, 9 and 10. Super Study rate and spacing - 76NA7, 76N05, 76JE8. Continuous cropping - 75LG26, 75ES7. Rates, Methods and times of Super - 76KA3, 76JE3. Super on old land lupins - 76BA3 & 4, 76A4 76E3 & 4, 76WH7 & 8. High Rainfall Pasture Trials - 1976 Soil Testing Series - 76BY3,·4, 5, &·6, Skirrow 76BR10, 11, 12, 16 & 17. 76HA2; 3, 4, 5, 6 & 7 76KE5, 6, 7, 8, 9 & 10. 76MA5 & 6. P x S series - 76KE3 & 4, 76MA2 & 4. Cross Plot x Soil test series - 75AL5, 75DE2, 3, 4, 5 & 7. 75Bu8 & 10, 75BY6 & 8 75BR11, 12 & 13, 75AR4, 75HA7
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