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  • 1
    Electronic Resource
    Electronic Resource
    Force prediction in permanent magnet flat linear motors (abstract) : The 5th Joint MMM−Intermag Conference (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 70 (1991), S. 6638-6638 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The advent of neodymium iron boron rare-earth permanent magnet material has afforded the opportunity to construct linear machines of high force to weight ratio. The paper describes the design and construction of an axial flux machine and rotating drum test rig. The machine occupies an arc of 45° on a drum 1.22 m in diameter. The excitation is provided by blocks of NdFeB material which are skewed in order to minimize the force variations due to slotting. The stator carries a three-phase short-chorded double-layer winding of four poles. The machine is supplied by a PWM inverter the fundamental component of which is phase locked to the rotor position so that a "dc brushless'' drive system is produced. Electromagnetic forces including ripple forces are measured at supply frequencies up to 100 Hz. They are compared with finite-element analysis which calculates the force variation over the time period. The paper then considers some of the causes of ripple torque. In particular, the force production due solely to the permanent magnet excitation is considered. This has two important components each acting along the line of motion of the machine, one is due to slotting and the other is due to the finite length of the primary. In the practical machine the excitation poles are skewed to minimize the slotting force and the effectiveness of this is confirmed by both results from the experiments and the finite-element analysis. The end effect force is shown to have a space period of twice that of the excitation. The amplitude of this force and its period are again confirmed by practical results.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.349834
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  • 2
    Electronic Resource
    Electronic Resource
    Three-dimensional modeling techniques applied to regions with small susceptibility variations (abstract) : The 40th annual conference on magnetism and magnetic materials (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 4685-4685 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The article considers the modeling of regions where the susceptibility is 0.01–10 ppm different from the majority of the space of interest. These calculations are of use in MR imaging, for example, in one possible application, the susceptibility of an haemorrhagic deposit could be adduced. Two methods are considered. Firstly, the use of finite element modeling using double precision arithmetic in conjunction with carefully set convergence limits. Secondly, a method which considers the induced polarity in the region of enhanced susceptibility, and calculates the difference field. The work is validated initially by calculating analytically the field perturbation produced by a sphere of susceptibility of 1×10−8 and comparing the results with the two methods given above. It is shown that excellent agreement is obtained. As a further confirmation the field produced by a short cylindrical object was measured experimentally using a MR scanner and again the applicability of both modeling techniques was confirmed. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.361704
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  • 3
    Electronic Resource
    Electronic Resource
    Effects of slot closure by soft magnetic powder wedge material in axial-field permanent magnet brushless machines : The 40th annual conference on magnetism and magnetic materials (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 5554-5556 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The article reports on a study of the effects of slot closure in axial-field permanent magnet brushless machines by a two-dimensional finite element method (2D FEM) of analysis. The closure of the slots is made by using soft magnetic powder wedge material. Parameter values and machine performance for the open and closed slot configuration are computed. In order to test the 2D FEM model, calculated results are compared with measurements and favorable agreement is shown. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.362240
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  • 4
    Electronic Resource
    Electronic Resource
    Determination of Active Hydrogen in Organic Compounds by Exchange with Tritiated Isopropyl Alcohol (1959)
    s.l. : American Chemical Society
    Analytical chemistry 31 (1959), S. 555-558 
    Details
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ac50164a029
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  • 5
    Electronic Resource
    Electronic Resource
    Effects of pole flux distribution in a homopolar linear synchronous machine : 38th Annual Conference on Magnetism and Magnetic Materials (1994)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 75 (1994), S. 6987-6989 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Linear forms of synchronous electrical machine are at present being considered as the propulsion means in high-speed, magnetically levitated (Maglev) ground transportation systems. A homopolar form of machine is considered in which the primary member, which carries both ac and dc windings, is supported on the vehicle. Test results and theoretical predictions are presented for a design of machine intended for driving a 100 passenger vehicle at a top speed of 400 km/h. The layout of the dc magnetic circuit is examined to locate the best position for the dc winding from the point of view of minimum core weight. Measurements of flux build-up under the machine at different operating speeds are given for two types of secondary pole: solid and laminated. The solid pole results, which are confirmed theoretically, show that this form of construction is impractical for high-speed drives. Measured motoring characteristics are presented for a short length of machine which simulates conditions at the leading and trailing ends of the full-sized machine. Combination of the results with those from a cylindrical version of the machine make it possible to infer the performance of the full-sized traction machine. This gives 0.8 pf and 0.9 efficiency at 300 km/h, which is much better than the reported performance of a comparable linear induction motor (0.52 pf and 0.82 efficiency). It is therefore concluded that in any projected high-speed Maglev systems, a linear synchronous machine should be the first choice as the propulsion means.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.356750
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  • 6
    Electronic Resource
    Electronic Resource
    The Preparation of ▵5,7-Steroidal Dienes1 (1953)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 75 (1953), S. 3255-3258 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja01109a062
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  • 7
    Electronic Resource
    Electronic Resource
    Survival, growth and productivity of tree species under evaluation for agroforestry to control salinity in the Western Australian wheatbelt (1993)
    Springer
    Agroforestry systems 21 (1993), S. 223-237 
    Details
    ISSN: 1572-9680
    Keywords: agroforestry ; coppice ; Eucalyptus ; eucalyptus oil ; establishment ; fodder trees
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Survival and growth were investigated for 10Eucalyptus species and 2 fodder tree species planted for salinity control in the wheatbelt of Western Australia. After two years of growth the trees were harvested to determine fodder biomass production and yields of cineole from the eucalyptus leaf oil. Subsequent harvests were conducted at three and five years after planting. At each harvest, biomass production from fodder species was greater than from most species of eucalypts. Biomass yields from eucalypts were variable, and there were no consistent trends in the productivity of the different species for the three harvests. Leaf cineole concentrations and cineole yields were low after two years of growth, but after three and five years cineole yields were generally higher from all species.E. kochii subspp.plenissima andkochii, E. horistes, E. radiata andE. angustissima produced consistently high cineole yields after three and five years. These species appear to have potential for the production of high grade eucalyptus oil in the wheatbelt of Western Australia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00705242
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  • 8
    Electronic Resource
    Electronic Resource
    Curing characteristics of a composite matrix (1986)
    Springer
    Journal of materials science 21 (1986), S. 4289-4295 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The account describes investigations into the variations of specific volume and viscosity of a typical high-performance epoxy resin during various time-temperature cycles. The work was undertaken primarily to provide additional background information relating to the nature and causes of “fibre kinking” which has been observed in laminates comprising epoxy-carbon composite. The investigation has quantified certain characteristics of the resin which are presumed to be major contributory factors in the occurrence of fibre kinking. It is concluded that a simple solution to the general problem cannot be identified, although some possibilities are discussed for individual cases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01106543
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  • 9
    Electronic Resource
    Electronic Resource
    The influence of crop management on the water balance of lupin and wheat crops on a layered soil in a Mediterranean climate (2000)
    Springer
    Plant and soil 221 (2000), S. 239-251 
    Details
    ISSN: 1573-5036
    Keywords: drainage ; duplex soil ; evapotranspiration ; lupin ; waterlogging ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The influence of time of sowing and sowing density on evapotranspiration and drainage loss beneath wheat (Triticum aestivum cv. Spear) and lupin (Lupinus angustifolius cv. Gungurru) crops grown on a layered soil was investigated for three seasons in a Mediterranean climate in Western Australia. The aim of the study was to investigate whether managing crops to maximise their canopy growth would increase their water use and minimise groundwater recharge contributing to dryland salinity. A soil water balance approach was used to estimate evapotranspiration, with changes in soil water content measured with a neutron water meter. The study was carried out on a layered soil typical of agricultural soils in the region with variable depth to clay (0.22–0.38 m) and a marked contrast in hydraulic properties between the topsoil and subsoil. As a result of the low permeability subsoil, a perched water table occurred in the sandy topsoil in each of the three seasons under study during winter when rainfall was high and potential evaporation low. Perched water tables persisted for 2–3 months, with hydraulic gradients consistently downward causing drainage losses to occur. Although crop management had a large influence on shoot and root development, evapotranspiration from the different treatments was generally similar. Drainage losses were not influenced by either crop type, time of sowing or sowing density, because potential evaporation and hence evapotranspiration was low during the period when drainage losses occurred. The total drainage loss measured in each season was different, with losses ranging from 20.1 to 22.2 mm in 1990, from 40.4 to 46.7 mm in 1991 and from 49.4 to 66.6 mm in 1992. The increase in drainage loss from 1990 to 1992 was a result of progressively more seasonal rainfall in 1990, 1991 and 1992. It was concluded that there was little scope to increase water use and decrease deep drainage through crop management for sites with climatic conditions where winter rainfall exceeds potential evaporation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004732706073
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  • 10
    Electronic Resource
    Electronic Resource
    Components of the water balance for tree species under evaluation for agroforestry to control salinity in the wheatbelt of Western Australia (1994)
    Springer
    Agroforestry systems 26 (1994), S. 157-169 
    Details
    ISSN: 1572-9680
    Keywords: agroforestry ; Eucalyptus ; evaporation ; fodder trees ; groundwater recharge ; water use efficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The soil water balance technique was used to study evaporation from two fodder tree species, tenEucalyptus species and annual pasture over a three year period after planting in the Western Australian wheatbelt. Evaporation is the total water loss by the processes of transpiration, evaporation from the soil surface and evaporation of water intercepted by plant canopies. Evaporation from both fodder trees and from seven of theEucalyptus species was greater than from pasture for one or more of the study years. The maximum difference in evaporation between trees and pasture was 82, 84 and 70 mm in the first, second and third study years, respectively. Higher evaporation from trees was associated with greater depletions in soil water than occurred beneath pasture. Upward movement of water from wet soil beneath the root zone was found under trees, with a maximum flux of 30 mm observed over a one year period beneathE. camaldulensis. The water use efficiency of fodder trees was significantly higher than for mostEucalyptus species, due to greater yields from fodder trees. Biomass production was found to be a good indicator of the water use of eucalypts over the first two years of growth, but the relationship between productivity and water use was found to differ for species with tree and mallee forms. In the third year of study, obvious differences in the relation between water use and yield were observed for some species of eucalypts with high evaporation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00711208
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