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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 117 for “"Flux density"”.
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Absolute Flux Density Measurement and Associated Instrumentation for Radio Astronomy below 100 MHz
… reports new measurements of the absolute flux densities of the brightest astrophysical sources visible from the northern hemisphere with O[10%] accuracy between 30-78 MHz. These measurements provide additional confidence in the existing understanding of the flux density spectra of these …
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A study of potential calibrators using the KAT-7 radio telescope
… the first steps towards identifying possible flux-density standards for short baseline interferometers such as the KAT-7. The systematic error for flux-density calibration at KAT-7 was estimated relative to 3C123, and it was found to be ~5% of the measured flux density. 18 (~47%) of the 38 …
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Characterizing the influence of neutron fields in causing single-event effects using portable detectors
… particles causing this effect. The neutron flux density in atmosphere is very low. For a good statistical certainty, millions of device hours are required to measure the event rate of a device in the natural environment. Event rates obtained in such testings are accurate. To reduce the cost …
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Finite Element Analysis Based Modeling of Magneto Rheological Dampers
… show a 2-D MR damper and generate the magnetic flux density along the MR Fluid gap. We can detect saturation by looking at the nodal solution for the magnetic flux density. Increasing the current in the model, results in an increase in magnetic induction. We studied four different configurations …
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Single-phase vs. Three-phase High Power High Frequency Transformers
… the core, which has the major limits of maximum flux density and temperature rise. The flux density should not reach the saturation value of the core, and temperature rise should meet specifications in different applications to assure the performance of the core (permeability, saturation flux …
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Variable air gap axial flux permanent magnet machine with mechanical field weakening
… two mechanical field weakening methods for axial flux permanent magnet machines, a type of machine that is popular for in-hub traction applications such as solar-powered electric vehicles, where the permanent magnets are surface mounted on magnet rings. After a review of the literature and the …
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Thermal-magnetic finite element model of a high frequency transformer
… vary with frequency, temperature, and magnetic flux density. Heat generation is, in turn, a function of the magnetic permeability, magnetic flux density, and frequency. Current design methods are either empirical or based on linear, uncoupled models. To better understand the relationship between …
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Branch, crown, tree and stand water flux in an 180-year-old loblolly pine plantation after thinning, fertilization, and throughfall exclusion treatments
Branch and tree sap flux density (SFD) was measured to evaluate the effects of thinning, fertilization, and throughfall exclusion treatments on water use by loblolly pine (Pinus taeda L.) trees. Variations in SFD at different radial xylem depths were also examined to improve estimates of tree water …
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Computer-aided-design of saturated magnetic lenses for electron microscopes
… has been concerned with the design of high flux density saturated objective lenses of both single and double polepiece types which may be energized by conventional coils and in some cases by superconducting coils. Such coils have the advantage of being small and capable of carrying high …
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Aspects of magnetisation and iron loss characteristics in switched-reluctance and permanent-magnet machines
… in synchronous reactances and permanent magnet flux are presented. Finite element simulations are used to show the variation of magnet flux under loading, a condition ignored in classical analysis methods. The final section discusses the analysis of magnetisation characteristics of electrical …
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The distribution of dark matter at large scales and in gravitational lenses
… research study presented here concerns the flux ratio anomaly in the quadruply imaged strong gravitational lens, B1422+231, in which the contribution of $10-10^3M_{\odot}$ primordial black holes (PBHs) as a potential dark matter constituent is examined. I review the theory of gravitational …
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High resolution spectropolarimetric diagnostics of weak, small-scale magnetic fields in the solar photosphere
… features (LPFs) are found with magnetic flux density 130 − 150 G, appearing preferentially at granule-intergranular lane boundaries. The weak magnetic field appears to be organized in terms of complex ‘loop-like’ structures, with transverse fields often flanked by opposite polarity …
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Application of improved core loss formulations to machine design
… either at 50/60Hz, 1.5T or curves (core loss vs. flux density) at 50 and/or 60Hz. There is growing need for lamination characterization at high flux densities (2T) and high frequencies (3.2 kHz) for novel electric machine designs operating at high speeds. The core loss measurement concept is …
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Theoretical considerations of the magnetohydrodynamic generator
… proportional to the fluid velocity and magnetic flux density, maintains a voltage drop across the electrodes and a current is generated when the electrodes are connected to an external load, closing the circuit. Thus energy is extracted from the fluid and delivered to an external load as …
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New evidence for flux cutting in type II superconductors.
… for cross flow and cutting of nonparallel flux lines in type II superconductors. A dramatic reversal is observed in the evolution of $B\sb{z}\sb{hole}$, the axial flux density in the cavity of a hollow cylinder when the magnitude of a helical magnetic field, $\vec H\sb{ext} = \\phi H\sb\phi …
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An attempt to measure the time delays of three gravitational lenses
… gravitational lenses, the campaign monitored ten flux and phase calibrators. The goal of this work was to measure the gravitational lens time delays. The ultimate goal was to estimate H₀ in a one-step calculation as proposed by Refsdal in 1964 [30]. I reduced the data using AIPS and DIFMAP …
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Uniform Field Distribution Using Distributed Magnetic Structure
… In a conventional toroidal inductor, the energy density is inversely proportional to the square of the radius. Thus, a designer would be unable to prescribe uniform field distribution to fully utilize the inductor volume for storing magnetic energy. To address this problem a new inductor design, …
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Analysis of a twin-spherical motor
… analysis begins with the derivation of current density waveforms for each geometry of slots and windings. From these current densities, flux densities are found analytically by the stream function method. Subsequently, the flux density is found numerically by using a finite difference program, …
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Analysis and Modelling of Fractional-Slot Concentrated-Wound Interior Permanent Magnet Machines
… magnetic saturation, and its airgap flux density are presented. The FSCW stator spatial MMF harmonics are analytically formulated, based on which, a novel heuristic algorithm is proposed for the design of optimal winding layouts for multiphase FSCW stators with different slot/pole …
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Wolter mirror microscope : novel neutron focussing and imaging optic
… of the system on the delivery of maximal flux density to the focal spot and the advantages of nesting the mirrors. I explore the imaging aspects of the optics by simulating surface imperfections, such as figure errors and finish errors, and compare the resulting distortions in the focal …
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