The Experts below are selected from a list of 300 Experts worldwide ranked by ideXlab platform
Andre Van Kets - One of the best experts on this subject based on the ideXlab platform.
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Hertz Namibia | Hertz Car Rental namibia - Compare & Save | Drive South Africa
2020Co-Authors: Andre Van KetsAbstract:Hertz car hire Namibia is a strong and established brand operating from all important transport hubs and airports.
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Hertz South Africa | Hertz Car Rental South Africa | Drive South Africa
2020Co-Authors: Andre Van KetsAbstract:Hertz car hire South Africa operates a extensive and established car rental service with multiple pick-up and drop-off locations
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Hertz South Africa | Hertz Car Rental South Africa - Compare & Save | Drive South Africa
2020Co-Authors: Andre Van KetsAbstract:Hertz car hire South Africa operates an extensive and established car rental service with multiple pick-ups and drop-off locations.
Fabrice Thouverez - One of the best experts on this subject based on the ideXlab platform.
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assessment of a semi Hertzian method for determination of wheel rail contact patch
Vehicle System Dynamics, 2006Co-Authors: Xavier Quost, Michel Sebes, Anissa Eddhahak, Jeanbernard Ayasse, Hugues Chollet, Pierreetienne Gautier, Fabrice ThouverezAbstract:Wheel–rail contact calculations are essential for simulating railway vehicle dynamic behavior. Currently, these simulations usually use the Hertz contact theory to calculate normal forces and Kalker's ‘FASTSIM’ program to evaluate tangential stresses. Since 1996, new methods called semi-Hertzian have appeared: 5 7 (STRIPES). These methods attempt to estimate the non-elliptical contact patches with a discrete extension of the Hertz theory. As a continuation of 2, a validation of the STRIPES method for normal problem computing on three test cases is proposed in this article. The test cases do not fulfill the hypothesis required for the Hertz theory. Then, the Kalker's FASTSIM algorithm is adapted to STRIPES patch calculus to perform tangential forces computation. This adaptation is assessed using Kalker's CONTACT algorithm.
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Assessment of a semi-Hertzian method for determination of wheel–rail contact patch
Vehicle System Dynamics, 2006Co-Authors: Xavier Quost, Michel Sebes, Anissa Eddhahak, Jeanbernard Ayasse, Hugues Chollet, Pierreetienne Gautier, Fabrice ThouverezAbstract:Wheel–rail contact calculations are essential for simulating railway vehicle dynamic behavior. Currently, these simulations usually use the Hertz contact theory to calculate normal forces and Kalker's ‘FASTSIM’ program to evaluate tangential stresses. Since 1996, new methods called semi-Hertzian have appeared: 5 7 (STRIPES). These methods attempt to estimate the non-elliptical contact patches with a discrete extension of the Hertz theory. As a continuation of 2, a validation of the STRIPES method for normal problem computing on three test cases is proposed in this article. The test cases do not fulfill the hypothesis required for the Hertz theory. Then, the Kalker's FASTSIM algorithm is adapted to STRIPES patch calculus to perform tangential forces computation. This adaptation is assessed using Kalker's CONTACT algorithm.
Takashi Egawa - One of the best experts on this subject based on the ideXlab platform.
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frequency dispersion of drain conductance in algan gan hemt evaluated using sinusoidal wave signal input
Compound Semiconductor Integrated Circuit Symposium, 2013Co-Authors: Akio Wakejima, Tomotaka Narita, Akihiro Ando, Takashi Yamada, Takashi EgawaAbstract:We firstly demonstrate dynamic change in a drain conductance of an AlGaN/GaN HEMT from DC to high frequency using sinusoidal wave input signal from a network analyzer which can sweep from Hertz to giga Hertz. Prior to measurements, a bias-T which is adaptable at a frequency of Hertz to mega Hertz has been developed. S-parameter measurements sweeping from 5 Hz to 3 GHz reveals that the magnitude of S22 significantly decreases at a Hertz to mega Hertz frequency range although the phase of S22 is negligibly stable. Also, it is found that the drain conductance evaluated from drain I-V characteristics and that extracted from S- parameters at 100 Hz are comparable and that a drain conductance from mega Hertz to hundreds mega Hertz is stable, indicating that some trapping or de-trapping effects occur at this frequency range.
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Frequency Dispersion of Drain Conductance in AlGaN/GaN HEMT Evaluated Using Sinusoidal Wave Signal Input
2013 IEEE Compound Semiconductor Integrated Circuit Symposium (CSICS), 2013Co-Authors: Akio Wakejima, Tomotaka Narita, Akihiro Ando, Takashi Yamada, Takashi EgawaAbstract:We firstly demonstrate dynamic change in a drain conductance of an AlGaN/GaN HEMT from DC to high frequency using sinusoidal wave input signal from a network analyzer which can sweep from Hertz to giga Hertz. Prior to measurements, a bias-T which is adaptable at a frequency of Hertz to mega Hertz has been developed. S-parameter measurements sweeping from 5 Hz to 3 GHz reveals that the magnitude of S22 significantly decreases at a Hertz to mega Hertz frequency range although the phase of S22 is negligibly stable. Also, it is found that the drain conductance evaluated from drain I-V characteristics and that extracted from S- parameters at 100 Hz are comparable and that a drain conductance from mega Hertz to hundreds mega Hertz is stable, indicating that some trapping or de-trapping effects occur at this frequency range.
J S Wettlaufer - One of the best experts on this subject based on the ideXlab platform.
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Hertz beyond belief
Soft Matter, 2014Co-Authors: Andong He, J S WettlauferAbstract:We examine the validity of Hertz's linear elastic theory for central collisions of spheres using a viscoelastic model. This model explains why Hertz's theory is accurate in predicting the collision time and maximum contact area even when 40% of the kinetic energy is lost due to viscous dissipation. The main reason is that both the collision time and maximum contact area have a very weak dependence on the impact velocity. Moreover, we show that colliding objects exhibit an apparent size-dependent yield strength, which results from larger objects dissipating less energy at a given impact velocity.
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Hertz beyond belief
arXiv: Classical Physics, 2013Co-Authors: Andong He, J S WettlauferAbstract:We examine the validity of Hertz's linear elastic theory for central collisions using a viscoelastic model. This model explains why Hertz's theory is accurate in predicting the collision time and maximum contact area even when $40\%$ of the kinetic energy is lost due to viscous dissipation. The main reason is that both the collision time and maximum contact area have a very weak dependence on the impact velocity. Moreover, we show that colliding objects exhibit an apparent size dependent yield strength, which results from larger objects dissipating less energy at a given impact velocity.
Darren C Dowell - One of the best experts on this subject based on the ideXlab platform.
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submillimeter array polarimetry with Hertz
The Astrophysical Journal, 1998Co-Authors: Darren C Dowell, R H Hildebrand, D A Schleuning, John E Vaillancourt, Jessie L Dotson, G Novak, T Renbarger, Martin HoudeAbstract:We describe the characteristics of the 350 μm polarimeter Hertz learned from laboratory tests and recent observations at the Caltech Submillimeter Observatory. Hertz contains a pair of 32 element arrays with 18'' pixel spacing and 20'' resolution. The instrument has been improved since initial observations in 1994 and 1995; the detector noise is now below the sky background noise. In excellent weather conditions on Mauna Kea, the noise-equivalent flux density (NEFD) for the measurement of polarized flux is 3-4 Jy Hz-1/2. The subtraction of correlated sky noise accomplished by the two-array design is crucial for achieving this performance. A method for analysis of our polarization data in the presence of the correlated noise is described. The instrumental polarization of Hertz is less than 0.5% across the detector array. Systematic errors in the measurement of polarization are less than 0.2%. We present a 350 μm polarization map of Sgr B2 with 140 detections at greater than 3 σ significance. For our current database of all 350 μm polarization measurements, the median polarization is 1.1%.
