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Wyszukujesz frazę "Planck constant" wg kryterium: Temat


Wyświetlanie 1-3 z 3
Tytuł:
Establishing and characterizing a permanent magnet system for the prototype of NISs Kibble balance
Autorzy:
Emira, Sayed
Shaaban, E. R.
Rashad, M. M.
Gelany, Shaker A.
Powiązania:
https://bibliotekanauki.pl/articles/2203366.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Kibble balance
Planck constant
magnet system
magnetic field
Opis:
The Kibble balance experiment is used to redefine the kilogram as a unit of mass based on the Planck constant. To demonstrate and understand the basic principle of the Kibble balance, the National Institute of Standards (NIS)-Egypt has constructed a prototype Kibble balance that can measure gram-level masses with 0.01% relative uncertainty. Through the construction of this prototype, the challenges can be studied and addressed to overcome the weaknesses of NIS’s prototype. This study presents the design and construction of the prototype Kibble balance. It also focuses on the design and performance of the magnetic system, which is a crucial element of the Kibble balance. Analytical modeling and finite element analysis were used to evaluate and improve the magnet system. Several other aspects were also discussed, including the yoke’s material and enhancing the magnetic profile within the air gap of the magnet system. Over a vertical distance of 30 mm inside the air gap, the magnetic flux density was found to be 0.3 T, and the uniformity was found to be 8 x 10-5.
Źródło:
Metrology and Measurement Systems; 2023, 30, 1; 3--16
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Josephson Voltage Metrology for Watt Balance Experiments at NIST
Autorzy:
Tang, Y.-H.
Powiązania:
https://bibliotekanauki.pl/articles/114716.pdf
Data publikacji:
2016
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
Josephson voltage standard
Planck constant
programmable Josephson voltage standard
International System of Units (SI)
watt balance
uncertainty
Opis:
The Planck constant, h, is one of the seven fundamental constants proposed to redefine the SI. It has been measured by the watt balance experiments since the 1980s. In its early days, the watt balance experiment played a vital role in determining the Josephson constant KJ-90 which was adopted internationally on January 1, 1990. The development of Josephson technology, especially the implementation of the Programmable Josephson Voltage Standard (PJVS) in voltage metrology has improved the uncertainty of voltage measurement in the watt balance experiment by more than two orders of magnitude. The Josephson voltage measurement in the watt balance experiment plays an important role in the proposed SI redefinition based on a set of fundamental constants. This paper will describe a brief history from the original NIST-1 watt balance in 1980s up to the most recent development of the NIST-4 watt balance. We will also discuss the role of voltage metrology in the watt balance experiments and the impact of the SI redefinition to the voltage metrology in the future.
Źródło:
Measurement Automation Monitoring; 2016, 62, 2; 42-45
2450-2855
Pojawia się w:
Measurement Automation Monitoring
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental Evidence That Hubble’s Parameter Could Be Reflected in Local Physical and Chemical Reactions: Support for Mach’s Principle of Imminence of the Universe
Autorzy:
Persinger, M.A.
Powiązania:
https://bibliotekanauki.pl/articles/412010.pdf
Data publikacji:
2013
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Hubble constant
Planck's length expansions
protons and electrons
point durations
Mach’s principle
local estimates
Opis:
Mach’s principle of immanence of the universe requires the behavior of local matter to depend upon the remainder of the universe. Hubble’s constant could be employed to calculate the inference of this condition. More than a decade ago specific types of temporally patterned magnetic fields generated by serial 3 ms point durations were shown to produce conspicuous biochemical effects. When the product of this duration and the diameter of a proton was divided into Planck’s Length the estimated Hubble’ parameter was 66.7 ±1.3 km∙ s-1•MParsec-1 which is remarkably similar to the current value of 67.8 km∙ s-1. Photon emissions from chemoluminescent reactions and discrete shifts in pH within spring water during exposure to specific patterns of magnetic fields revealed optimal responses with remarkably similar z-transformations when point durations of the constructive voltages were 3 ms or 1 ms but not 2, 4, or 5 ms. Cumulative results indicate proton (3 ms) and electron (~1.5 ms) processes. These results support Mach’s contention and indicate that relatively accurate inferences of the Hubble parameter might be obtained with more precise instrumentation on the terrestrial surface.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2013, 11; 86-92
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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