The Experts below are selected from a list of 84 Experts worldwide ranked by ideXlab platform

Anselmi Alberto - One of the best experts on this subject based on the ideXlab platform.

  • Testing the Equivalence Principle in space after the MICROSCOPE mission
    'American Physical Society (APS)', 2018
    Co-Authors: Nobili, Anna M., Anselmi Alberto
    Abstract:

    Tests of the Weak Equivalence Principle can reveal a new, composition dependent, force of nature or disprove many models of new physics. For the first time such a test is successfully carried out in space by the MICROSCOPE satellite. Early results show no violation sourced by the Earth for Pt and Ti test masses with random errors (after 8.26d of integration time) of about 1 part in 1e14, and similar systematic errors.It improves by 10 times over the best ground tests with rotating torsion balances despite 70 times less sensitivity to differential accelerations, thanks to the much stronger driving signal in orbit. The test is limited by thermal noise from internal damping in the gold wires used for Electrical Grounding. This noise was shown to decrease when the s/c was set to rotate faster than planned. The result will improve by the end of the mission, as thermal noise decreases with more data. Not so systematic errors. We investigate major non-gravitational effects and find that the Pt-Pt sensor does not allow their separation from the signal. The early test reports an upper limit of systematic errors in the Pt-Ti sensor which are not detected in the Pt-Pt one, hence would not be distinguished from a violation. Once all the integration time is used to reduce random noise there will be no time left to check systematics. MICROSCOPE demonstrates the huge potential of space for WEP tests of very high precision and indicates how to reach it. To realize the potential, a new experiment needs the spacecraft to be in rapid, stable rotation around the symmetry axis, needs high quality state-of-the-art mechanical suspensions, and must allow systematic checks. The design of the "Galileo Galilei" (GG) experiment, aiming to test the WEP to 1 part in 1e17 unites all the needed features, indicating that a quantum leap in space is possible provided the new experiment heeds the lessons of MICROSCOPE.Comment: To appear on Physical Review

  • Testing the equivalence principle in space after the MICROSCOPE mission
    'American Physical Society (APS)', 2018
    Co-Authors: Nobili, Anna M., Anselmi Alberto
    Abstract:

    Tests of the weak equivalence principle (WEP) can reveal a new, composition dependent, force of nature, or disprove many models of new physics. For the first time, such a test is being successfully carried out in space by the MICROSCOPE satellite. Early results show no violation of the WEP sourced by the Earth for Pt and Ti test masses with random errors (after 8.26 d of integration time) of about 1 part in 1014 and systematic errors of the same magnitude. This result improves by about 10 times over the best ground tests with rotating torsion balances despite 70 times less sensitivity to differential accelerations, thanks to the much stronger driving signal in orbit. The measurement is limited by thermal noise from internal damping in the gold wires used for Electrical Grounding, related to their fabrication and clamping. This noise was shown to decrease when the spacecraft was set to rotate faster than planned. The result will improve by the end of the mission, as thermal noise decreases with more data. Not so systematic errors. We investigate major nongravitational effects and find that MICROSCOPE's "zero-check" sensor, with test masses both made of Pt, does not allow their separation from the signal. The early test reports an upper limit of systematic errors in the Pt-Ti sensor, which are not detected in the Pt-Pt one, hence would not be distinguished from a violation. Once all the integration time available is used to reduce random noise, there will be no time left to check systematics. MICROSCOPE demonstrates the huge potential of space for WEP tests of very high precision and indicates how to reach it. To realize the potential, a new experiment needs the spacecraft to be in rapid, stable rotation around the symmetry axis (by conservation of angular momentum), needs high quality state-of-the-art mechanical suspensions as in the most precise gravitational experiments on ground, and must allow multiple checks to discriminate a violation signal from systematic errors. The design of the "Galileo Galilei" (GG) experiment, aiming to test the WEP to 1 part in 1017 unites all the needed features, indicating that a quantum leap in space is possible provided the new experiment heeds the lessons of MICROSCOPE

Hu Yuancha - One of the best experts on this subject based on the ideXlab platform.

  • Flexible Graphite Composite Electrical Grounding Material and Its Application in Tower Grounding Grid of Power Transmission System
    Power system technology, 2014
    Co-Authors: Hu Yuancha
    Abstract:

    In allusion to the troubles that the existing metallic Grounding material has to be faced such as corrosion, the difficulty in transportation and construction, bigger clearance between the Grounding body and soil and easy to be stolen, a new flexible graphite composite Electrical Grounding material is developed. Firstly, the Grounding characteristics of this new Grounding material is described briefly and the influences of electromagnetic characteristics of this Grounding material on impulse Grounding resistance are analyzed, and further the structural improvement of this new Grounding material is performed; secondly, the feasibility of applying this new Grounding material in the transmission tower Grounding grid is analyzed; finally, a brief illustration of the application of this new Grounding material in 110 kV transmission tower Grounding project is given and it is shown that the new graphite composite Grounding material can meet the demand of actual engineering under poor geological ground condition.

Siow Chun Lim - One of the best experts on this subject based on the ideXlab platform.

  • behaviour of backfill materials for Electrical Grounding systems under high voltage conditions
    journal of engineering science and technology, 2015
    Co-Authors: Siow Chun Lim, Chandima Gomes, Mohd Zainal Abidin Ab Kadir, Ghasem Nourirad, Z A Malek
    Abstract:

    Backfill materials like Bentonite and cement are effective in lowering Grounding resistance of electrodes for a considerable period. During lightning, switching impulses and earth fault occurrences in medium and high voltage networks, the Grounding system needs to handle extremely high currents either for a short duration or prolonged period respectively. This paper investigates the behaviour of bentonite, cement and sand under impulse and alternating high voltage (50Hz) conditions. Fulguritic-formation was observed in all materials under alternating high voltage. The findings reveal that performance of Grounding systems under high voltage conditions may significantly change from the outcomes anticipated at design stage.

  • characterizing of bentonite with chemical physical and Electrical perspectives for improvement of Electrical Grounding systems
    2013
    Co-Authors: Siow Chun Lim, Chandima Gomes, Zainal Abidin, Ab Kadir
    Abstract:

    The application of bentonite as Electrical Grounding improvement material (GIM) has been investigated. Bentonite is a type of clay which has high tendency to absorb and retain water, and swells. This property makes it desirable for applications in Grounding system improvement as they could result in lowering as well as minimizing the fluctuation of ground resistance over a long period of time. However, these properties depend on the type of bentonite. Commercially, there are two types of available bentonite; namely sodium bentonite and calcium bentonite. Several experiments were conducted to determine the chemical composition, water absorption rate, swelling capability; density and resistivity of calcium bentonite since such information are not available in the literature.

Nobili, Anna M. - One of the best experts on this subject based on the ideXlab platform.

  • Testing the Equivalence Principle in space after the MICROSCOPE mission
    'American Physical Society (APS)', 2018
    Co-Authors: Nobili, Anna M., Anselmi Alberto
    Abstract:

    Tests of the Weak Equivalence Principle can reveal a new, composition dependent, force of nature or disprove many models of new physics. For the first time such a test is successfully carried out in space by the MICROSCOPE satellite. Early results show no violation sourced by the Earth for Pt and Ti test masses with random errors (after 8.26d of integration time) of about 1 part in 1e14, and similar systematic errors.It improves by 10 times over the best ground tests with rotating torsion balances despite 70 times less sensitivity to differential accelerations, thanks to the much stronger driving signal in orbit. The test is limited by thermal noise from internal damping in the gold wires used for Electrical Grounding. This noise was shown to decrease when the s/c was set to rotate faster than planned. The result will improve by the end of the mission, as thermal noise decreases with more data. Not so systematic errors. We investigate major non-gravitational effects and find that the Pt-Pt sensor does not allow their separation from the signal. The early test reports an upper limit of systematic errors in the Pt-Ti sensor which are not detected in the Pt-Pt one, hence would not be distinguished from a violation. Once all the integration time is used to reduce random noise there will be no time left to check systematics. MICROSCOPE demonstrates the huge potential of space for WEP tests of very high precision and indicates how to reach it. To realize the potential, a new experiment needs the spacecraft to be in rapid, stable rotation around the symmetry axis, needs high quality state-of-the-art mechanical suspensions, and must allow systematic checks. The design of the "Galileo Galilei" (GG) experiment, aiming to test the WEP to 1 part in 1e17 unites all the needed features, indicating that a quantum leap in space is possible provided the new experiment heeds the lessons of MICROSCOPE.Comment: To appear on Physical Review

  • Testing the equivalence principle in space after the MICROSCOPE mission
    'American Physical Society (APS)', 2018
    Co-Authors: Nobili, Anna M., Anselmi Alberto
    Abstract:

    Tests of the weak equivalence principle (WEP) can reveal a new, composition dependent, force of nature, or disprove many models of new physics. For the first time, such a test is being successfully carried out in space by the MICROSCOPE satellite. Early results show no violation of the WEP sourced by the Earth for Pt and Ti test masses with random errors (after 8.26 d of integration time) of about 1 part in 1014 and systematic errors of the same magnitude. This result improves by about 10 times over the best ground tests with rotating torsion balances despite 70 times less sensitivity to differential accelerations, thanks to the much stronger driving signal in orbit. The measurement is limited by thermal noise from internal damping in the gold wires used for Electrical Grounding, related to their fabrication and clamping. This noise was shown to decrease when the spacecraft was set to rotate faster than planned. The result will improve by the end of the mission, as thermal noise decreases with more data. Not so systematic errors. We investigate major nongravitational effects and find that MICROSCOPE's "zero-check" sensor, with test masses both made of Pt, does not allow their separation from the signal. The early test reports an upper limit of systematic errors in the Pt-Ti sensor, which are not detected in the Pt-Pt one, hence would not be distinguished from a violation. Once all the integration time available is used to reduce random noise, there will be no time left to check systematics. MICROSCOPE demonstrates the huge potential of space for WEP tests of very high precision and indicates how to reach it. To realize the potential, a new experiment needs the spacecraft to be in rapid, stable rotation around the symmetry axis (by conservation of angular momentum), needs high quality state-of-the-art mechanical suspensions as in the most precise gravitational experiments on ground, and must allow multiple checks to discriminate a violation signal from systematic errors. The design of the "Galileo Galilei" (GG) experiment, aiming to test the WEP to 1 part in 1017 unites all the needed features, indicating that a quantum leap in space is possible provided the new experiment heeds the lessons of MICROSCOPE

Shaorong Liu - One of the best experts on this subject based on the ideXlab platform.

  • ion exchange resin bead decoupled high pressure electroosmotic pump
    Analytical Chemistry, 2009
    Co-Authors: Bingcheng Yang, Feifang Zhang, Xinmiao Liang, Purnendu K Dasgupta, Shaorong Liu
    Abstract:

    We describe an electroosmotic pump (EOP) that utilizes a cation exchange resin bead as the electric field decoupler. The resin bead serves as a Electrical Grounding joint without fluid leakage, thus eliminating electrolytic gas interference from the flow channels. The arrangement is easy to practice from readily available components, displays a very low Electrical resistance, and is capable of bearing high backpressure (at least 3200 psi). We use a silica xerogel column as the EOP element to pump water and demonstrate a complete capillary ion chromatograph (CIC), which uses a similar bead based microelectrodialytic generator (μ-EDG) to generate a KOH eluent from the pumped water. We observed good operational stability of the complete arrangement over long periods.