The Experts below are selected from a list of 288 Experts worldwide ranked by ideXlab platform
B. Trinchera - One of the best experts on this subject based on the ideXlab platform.
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realization of the Farad from the dc quantum hall effect with digitally assisted impedance bridges
Metrologia, 2010Co-Authors: L. Callegaro, Vincenzo Delia, B. TrincheraAbstract:A traceability chain for the derivation of the Farad from dc quantum Hall effect has been recently implemented at INRIM. The main components of the chain are two coaxial transformer bridges: a resistance ratio bridge and a quadrature bridge, both operating at 1541 Hz.Both bridges are energized and controlled by a polyphase sinewave direct-digital-synthesizer; the automated control of relative amplitudes and phases of the generator voltage outputs permits principal and auxiliary balances of each bridge to be achieved. Such a technique, which may be called digital assistance, is implemented for the first time in an ohm–Farad traceability chain.The relative standard uncertainty in the realization of the Farad, at the level of 1000 pF, is estimated to be 64 × 10−9. A first verification of the realization is given by a comparison with the maintained INRIM capacitance standard, where an agreement within a relative combined standard uncertainty of 420 × 10−9 is obtained.
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Realization of the Farad from the dc quantum Hall effect with digitally-assisted impedance bridges
Metrologia, 2010Co-Authors: L. Callegaro, V. D'elia, B. TrincheraAbstract:A new traceability chain for the derivation of the Farad from dc quantum Hall effect has been implemented at INRIM. Main components of the chain are two new coaxial transformer bridges: a resistance ratio bridge, and a quadrature bridge, both operating at 1541 Hz. The bridges are energized and controlled with a polyphase direct-digital-synthesizer, which permits to achieve both main and auxiliary equilibria in an automated way; the bridges and do not include any variable inductive divider or variable impedance box. The relative uncertainty in the realization of the Farad, at the level of 1000 pF, is estimated to be 64E-9. A first verification of the realization is given by a comparison with the maintained national capacitance standard, where an agreement between measurements within their relative combined uncertainty of 420E-9 is obtained.
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Determination of the Farad from dc quantum hall effect, by using digital ac bridges
2008 Conference on Precision Electromagnetic Measurements Digest, 2008Co-Authors: B. Trinchera, V. D'elia, L. CallegaroAbstract:A new traceability chain for the derivation of the Farad from dc quantum Hall effect is under characterization at INRIM. Main steps are performed by new ratio and quadrature coaxial ac bridges. The bridges are based on a polyphase digital synthesizer and do not employ variable dividers or impedances to achieve equilibrium. Preliminary measurements show an agreement, between the new Farad determination and the maintained unit, better than 2 times 10-7.
Stephen F. Sundlof - One of the best experts on this subject based on the ideXlab platform.
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The Food Animal Residue Avoidance Databank (Farad). Past, present and future.
The Veterinary clinics of North America. Food animal practice, 1999Co-Authors: Michael Payne, Arthur L. Craigmill, Jim E. Riviere, Ronald E. Baynes, Alistair I. Webb, Stephen F. SundlofAbstract:The Food Animal Residue Avoidance Databank (Farad) was created in 1982 as a cooperative state and federal educational outreach program. Farad's mission has remained unchanged in the last fifteen years: to assist producers, veterinarians, and allied professionals in the production of animal foods free of illegal chemical contaminants. At its core, Farad is a collection of databases that users can efficiently access with the assistance of program experts. In order to meet emerging challenges related to technical and trade issues in food safety, current Farad projects include inter-species data extrapolation, novel kinetic modeling, and international information exchange.
L. Callegaro - One of the best experts on this subject based on the ideXlab platform.
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realization of the Farad from the dc quantum hall effect with digitally assisted impedance bridges
Metrologia, 2010Co-Authors: L. Callegaro, Vincenzo Delia, B. TrincheraAbstract:A traceability chain for the derivation of the Farad from dc quantum Hall effect has been recently implemented at INRIM. The main components of the chain are two coaxial transformer bridges: a resistance ratio bridge and a quadrature bridge, both operating at 1541 Hz.Both bridges are energized and controlled by a polyphase sinewave direct-digital-synthesizer; the automated control of relative amplitudes and phases of the generator voltage outputs permits principal and auxiliary balances of each bridge to be achieved. Such a technique, which may be called digital assistance, is implemented for the first time in an ohm–Farad traceability chain.The relative standard uncertainty in the realization of the Farad, at the level of 1000 pF, is estimated to be 64 × 10−9. A first verification of the realization is given by a comparison with the maintained INRIM capacitance standard, where an agreement within a relative combined standard uncertainty of 420 × 10−9 is obtained.
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Realization of the Farad from the dc quantum Hall effect with digitally-assisted impedance bridges
Metrologia, 2010Co-Authors: L. Callegaro, V. D'elia, B. TrincheraAbstract:A new traceability chain for the derivation of the Farad from dc quantum Hall effect has been implemented at INRIM. Main components of the chain are two new coaxial transformer bridges: a resistance ratio bridge, and a quadrature bridge, both operating at 1541 Hz. The bridges are energized and controlled with a polyphase direct-digital-synthesizer, which permits to achieve both main and auxiliary equilibria in an automated way; the bridges and do not include any variable inductive divider or variable impedance box. The relative uncertainty in the realization of the Farad, at the level of 1000 pF, is estimated to be 64E-9. A first verification of the realization is given by a comparison with the maintained national capacitance standard, where an agreement between measurements within their relative combined uncertainty of 420E-9 is obtained.
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Determination of the Farad from dc quantum hall effect, by using digital ac bridges
2008 Conference on Precision Electromagnetic Measurements Digest, 2008Co-Authors: B. Trinchera, V. D'elia, L. CallegaroAbstract:A new traceability chain for the derivation of the Farad from dc quantum Hall effect is under characterization at INRIM. Main steps are performed by new ratio and quadrature coaxial ac bridges. The bridges are based on a polyphase digital synthesizer and do not employ variable dividers or impedances to achieve equilibrium. Preliminary measurements show an agreement, between the new Farad determination and the maintained unit, better than 2 times 10-7.
Michael Payne - One of the best experts on this subject based on the ideXlab platform.
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Extralabel use of penicillin in food animals.
Journal of the American Veterinary Medical Association, 2006Co-Authors: Michael Payne, Arthur L. Craigmill, Jim E. Riviere, Alistair I. WebbAbstract:Penicillin is one of the most commonly detected drug residues in tissues and milk, and is the antimicrobial for which information is most often sought through Farad.
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The Food Animal Residue Avoidance Databank (Farad). Past, present and future.
The Veterinary clinics of North America. Food animal practice, 1999Co-Authors: Michael Payne, Arthur L. Craigmill, Jim E. Riviere, Ronald E. Baynes, Alistair I. Webb, Stephen F. SundlofAbstract:The Food Animal Residue Avoidance Databank (Farad) was created in 1982 as a cooperative state and federal educational outreach program. Farad's mission has remained unchanged in the last fifteen years: to assist producers, veterinarians, and allied professionals in the production of animal foods free of illegal chemical contaminants. At its core, Farad is a collection of databases that users can efficiently access with the assistance of program experts. In order to meet emerging challenges related to technical and trade issues in food safety, current Farad projects include inter-species data extrapolation, novel kinetic modeling, and international information exchange.
B P Kibble - One of the best experts on this subject based on the ideXlab platform.
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realizing the Farad from two ac quantum hall resistances
Metrologia, 2009Co-Authors: J Schurr, V Burkel, B P KibbleAbstract:Since the quantum Hall resistance (QHR) measured with alternating current (ac) has reached the state of an excellent quantum standard of impedance, we have realized a quadrature bridge with two ac QHRs to accurately calibrate capacitance standards in terms of the SI value of the von-Klitzing constant, without the need for any calculable artefact. The advantages of the realized measuring chain, experimental tests of the coaxial ac bridges involved and the achieved relative uncertainty of 6 × 10−9 (k = 1) are discussed.
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Comparison of capacitance with AC quantized Hall resistance
IEEE Transactions on Instrumentation and Measurement, 1999Co-Authors: S W Chua, B P Kibble, A. HartlandAbstract:A quadrature bridge operating at a frequency of 1.233 kHz has been developed to compare 10 nF capacitances to the quantized Hall resistance on the i=2 plateau in order to realize the Farad in terms of R/sub K/. Portable precision ceramic capacitance transfer standards of remarkable performance have been developed for this purpose.
