Standard cells :

Hamer, Walter J.

doi:10.6028/nbs.mono.84

Cited by 13 publications

(2 citation statements)

References 42 publications

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“…With these values the assigned compositions are justified. However faring of 3CdSO4.8H2O in the diffusimeter as CdSO4 reflects the latter's kinetic stability and stable existence in the wet Weston Standard Cell [23]. Lowering of rates of 0.6M AgNO3-0.6M MCl diffusion in glucose solution reflects significant insight to the effect that metabolite flow (Table 3) are hindered by particle crowding in the blood.…”

Section: Resultsmentioning

confidence: 99%

Diffusimetry Renounces Graham’s Law, Achieves Diffusive Convection, Concentration Gradient Induced Diffusion, Heat and Mass Transfer

Khair

Dey

Harun‐Ur‐Rashid

et al. 2021

DDF

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Absolute diffusion rates of KMnO4 in vertical and flattened diffusimeters show the concentration gradient force as being stronger than the gravitational force. Hot water molecules move downward on self-diffusion against buoyancy. Diffusive convection (DC) in warm water and double-diffusive convection (DDC) in warm, saline water take place inside the diffusimeter with DDC transferring more heat than DC. In the diffusing medium the original reagents change or retain their compositions to give the diffusate molecules to diffuse. In water, the change is mostly hydration. The syngener BaCl2.2H2O separately with congeners 3CdSO4.8H2O, ZnSO4.7H2O, and ZnSO4.H2O presents two distinct pairs of overlapping concentration versus rate curves, first for having very close MWs of BaCl2 and CdSO4 and second for having ZnSO4.H2O as the common congener for both the zinc sulfates. Chlorides of Li, Na, and K diffusing at hindered rates in glucose solution show the least rate for LiCl inevitably on grounds of low mass and high Li+ hydration radius. Diffusion blocking occurs at higher glucose concentration. Diffusion of 0.6M AgNO3-0.6M NH4Cl standardizes this diffusimeter. Mass transfer of HCl, H2SO4, and H2C2O4 show oxalic acid diffusing as hydrate and 88 percentage transfer of sulfuric acid in 5 minutes. The Superdiffusive Anti Graham’s Law, Vd , is further consolidated by Ca (NO3)2-M2CO3(M = Na, K, NH4+) and Ca (NO3)2-Na2HPO4 diffusions. Odd and even diffusions are illustrated by AgNO3-NH4Cl and AgNO3-BaCl2 diffusions.

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Section: Resultsmentioning

confidence: 99%

Diffusimetry Renounces Graham’s Law, Achieves Diffusive Convection, Concentration Gradient Induced Diffusion, Heat and Mass Transfer

Khair

Dey

Harun‐Ur‐Rashid

et al. 2021

DDF

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“…To maintain long-term stability, a group of cells was used as a standard to compare the cells among each other and replace cells when necessary [1]. Since 1948, the National Reference Group of Standard Cells has consisted of 44 saturated Weston cells that were made from highly purified materials and assembled under controlled conditions [1,2].…”

Section: Introductionmentioning

confidence: 99%

A 10 V Transfer Standard Based on Low-Noise Solid-State Zener Voltage Reference ADR1000

Bülau,

Walter,

Zimmermann

2024

Metrology

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Voltage standards are widely used to transfer volts from Josephson voltage standards (JVSs) at national metrology institutes (NMIs) into calibration labs to maintain the volts and to transfer them to test equipment at production lines. Therefore, commercial voltage standards based on Zener diodes are used. Analog Devices Inc. (San Jose, CA, USA), namely, Eric Modica, introduced the ADR1000KHZ, a successor to the legendary LTZ1000, at the Metrology Meeting 2021. The first production samples were already available prior to this event. In this article, this new temperature-stabilized Zener diode is compared to several others as per datasheet specifications. Motivated by the superior parameters, a 10 V transfer standard prototype for laboratory use with commercial off-the-shelf components such as resistor networks and chopper amplifiers was built. How much effort it takes to reach the given parameters was investigated. This paper describes how the reference was set up to operate it at its zero-temperature coefficient (z.t.c.) temperature and to lower the requirements for the oven stability. Furthermore, it is shown how the overall temperature coefficient (t.c.) of the circuit was reduced. For the buffered Zener voltage, a t.c. of almost zero, and with amplification to 10 V, a t.c. of <0.01 µV/V/K was achieved in a temperature span of 15 to 31 °C. For the buffered Zener voltage, a noise of ~584 nVp-p and for the 10 V output, ~805 nVp-p were obtained. Finally, 850 days of drift data were taken by comparing the transfer standard prototype to two Fluke 7000 voltage standards according to the method described in NBS Technical Note 430. The drift specification was, however, not met.

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Superconducting Devices for Metrology and Standards

Kamper

1977

Superconductor Applications: SQUIDs and Machines

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Standard cells :

Cited by 13 publications

References 42 publications

Diffusimetry Renounces Graham’s Law, Achieves Diffusive Convection, Concentration Gradient Induced Diffusion, Heat and Mass Transfer

Diffusimetry Renounces Graham’s Law, Achieves Diffusive Convection, Concentration Gradient Induced Diffusion, Heat and Mass Transfer

A 10 V Transfer Standard Based on Low-Noise Solid-State Zener Voltage Reference ADR1000

Superconducting Devices for Metrology and Standards

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