Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision. It is important for certification institutions to explore methods for updating and transferring present standards, to accelerate the transfer of standard information and ensure present standards are implemented in a timely manner.

Standard Gibbs Energies of Transfer for KBPh_4 from Water to Water+PrOH and Water+TBA Mixtures and the Primary Medium Effects

The standard Gibbs energies of transfer (Δ tr G 0) for potassium tetraphenylborate (KBPh 4) have been studied in the systems of water and water +1 propanol (PrOH) as well as water and water + t butyl alcohol (TBA) at 298.15?K. The results show that -Δ tr G 0 exhibits a complicated changing pattern with the mole fraction of TBA( x (TBA)) or PrOH ( x (PrOH)), and Δ tr G 0 has the a maximum value at x (TBA) = 0.2 or x (PrOH)=0.2. Especially, -Δ tr G 0 of KBPh 4 changes unusually with increasing x (TBA) when x (TBA) < 0.05. The reasons for these changes were analyzed and discussed.

Effect of Different Conditions on the Structural Color of Konjac Glucomannan Particles

In this paper,molecular dynamics simulation was applied to synthesize a layered structural color from Konjac glucomannan（KGM） and the effect of particle diameter and temperature were investigated. A series of methods such as high voltage electric field treatment,the transfer matrix method and the CIE standard colorimetric system were simulated to obtain the chromaticity coordinates and to analyze the color changes of KGM particles. The results revealed that as the particle diameter increases,the structural color of KGM particles deflects towards the yellow wavelength within the visible spectrum; and as the reaction temperature rises,the structural color deflects towards the blue and violet wavelengths within the visible spectrum.

Fabrication of automatic switch for AC-DC completely automated measurement system at NIS

A fast automatic AC-DC switch is designed and fabricated mainly by a microcontroller and three double poles single throw reed relays.This new switch is introduced to establish a fully automated system for AC-DC measurements through ACDC transfer standards for the first time at the National Institute for standards(N IS)in Egypt.The implemented circuit of theautomatic AC-DC switch and its protection are presented in details.An AC voltage source is calibrated against DC voltagesource by using the demonstrated automatic switch as an application The calibrated voltage ranges are2V,6V,20V and60V as examples.The uncertainty budget is also evaluated for the calibrated values.

Establishment of Automated Multi-Range Multipliers Combined with TVC

An automated multi-range multipliers（range resistors）system is established for the AC voltage measurements by using a thermal voltage converter.It is performed automatically by selecting the appropriate multiplier whose voltage range contains the voltage to be measured without changing it manually through a new designed system.It consists of control part through a micro-controller controlled by specified prepared Lab-VIEW program and switching part through electronic relays in one circuit as clearly described in this work.It is used for measuring the ac voltage in the range from 1 V to 200 V.Also,it can be used for the voltage ranges up to 1 000 V by putting some factors into consideration.The AC-DC transfer differences for these multipliers combined with thermal voltage converter are determined automatically against another standard thermal voltage converter by using another Lab-VIEW program.

An Improved Design of a Fully Automated Multiple Output Micropotentiometer

This paper describes in details a new design of a fully automated multiple output micropotentiometer (?pot). A prototype has been built at the National Institute for Standards (NIS), Egypt to establish this highly improved AC voltage source in the millivolt range. The new device offers three different outputs covering a wide frequency range from only one outlet. This valuably supports the precise sourcing ranges of low AC voltage at NIS. The design and the operation theory of this prototype have been discussed in details. An automatic calibration technique has been introduced through specially designed software using the LabVIEW program to enhance the calibration technique and to reduce the uncertainty contributions. Relative small AC-DC differences of our prototype in the three output ranges are fairly verified. The expanded uncertainties of the calibration results for the three output ranges have been faithfully estimated. However, further work is needed to achieve the optimum performance of this new device.

Thermodynamic Properties of Transfer for Tetraphenylarsonium Tetraphylborate from Water to n-Alkanols

bInstitute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China Solubilities of tetraphenylarsonium tetraphenylborate (Ph 4AsB Ph 4) in water, methanol, ethanol, 1 propanol, 1 butanol, 1 pentanol, 1 hexanol and 1 octanol at T =293.2, 298.2, 303.2 and 308.2 K have been determined by spectrophotometry. The standard transfer Gibbs energy ( Δ tr G 0 w→s ) and entropy ( Δ tr S 0 w→s ) of Ph 4AsBPh 4 from water to the n alkanols at temerature from 293.2 K to 308.2 K have been obtained. Furthermore, the contribution of microscopic interaction to the standard Gibbs energy of transfer for Ph 4AsBPh 4 was calculated and discussed. The results show that the effect of hydrophobic interaction of Ph 4AsBPh 4 on its transfer process is the most important factor. According to the thermodynamical principle, the transfer process of Ph 4AsBPh 4 from water to the n alkanols is the entropy dominanted.

Standard Gibbs energies of transfer of rubidium tetraphenylborate from water to straight-chain n-alkanols

Solubilities of ribidium tetraphenylborate in water, methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol and l-octanol at 288.15, 298.15, 308.15, 318.15, 328.15 K have been determined by spectrophotometry. The standard Gibbs energy of transfer of ribidium tetraphenylborate from water to straight-chain n-alkanols and the primary medium effect of rubidium tetraphenylborate from 288.15 to 328.15 K have been calculated. Furthermore, the contribution of microscopic interactions to the standard Gibbs energy of transfer of rubidium tetraphenylborate in calculated and discussed.

Electromagnetic Technology for Vacuum Metrology in the Typical Development of a Metrological-Grade Spinning Rotor Gauge

As the most precise viscous vacuum gauge,the spinning rotor gauge is widely used in the aerospace,nuclear,semiconductor,and other fields because of its excellent accuracy and chemical inertness.Herein,a metrological-grade spinning rotor vacuum gauge is developed,and its performance is evaluated.It can be used for international comparison of vacuum standards and construction of national vacuum measurement traceability and transmission systems.This paper presents the design of a single-degree-of-freedom permanent magnet-biased rotor suspension system,a high-speed rotary stepper drive system,a rotational angular velocity determination system,a lateral damping system,and a transducer in detail.The change in residual drag is less than 0.49%after 50 minutes of start-up.There is good consistency and linearity in the range of 9.1727×10^(−5)Pa to 1.2081 Pa.