Pressure Calibration of Quarter-inch Working Standard Microphones by Comparison

2021 ◽  
Author(s):  
Andrew C.H. Au ◽  
◽  
Brenda H.S. Lam ◽  
Y.C. Kwan ◽  
Angus K.K. Tung
Keyword(s):  
Hong Kong ◽  
Automatic System ◽  
Measurement Model ◽  
Digital Calibration ◽  
Pressure Sensitivity ◽  
Calibration Laboratory ◽  
Working Standard ◽  
Calibration Process ◽  
Pressure Calibration ◽  
Comparison Technique

The Standards and Calibration Laboratory (SCL) in Hong Kong has developed a system for calibration of quarter-inch working standard (WS3) microphones which automates the measurement process and generates digital calibration certificates (DCC) to meet the growing demand for microphone calibration services in Hong Kong. This paper describes (i) the method of determining the pressure sensitivity of a microphone combination unit from 20 Hz to 20 kHz by the comparison technique in accordance with the International Standard IEC 61094-5, (ii) the measurement model and uncertainty evaluation, and (iii) the automatic system which facilitates the calibration process and generation of a digital calibration certificate.

The Tourist Stereotype Model: Positive and Negative Dimensions

2019 ◽  
Vol 59 (1) ◽  
pp. 37-51 ◽  
Author(s):  
Vincent Wing Sun Tung ◽  
Brian Edward Melville King ◽  
Serene Tse
Keyword(s):  
Hong Kong ◽  
Measurement Model ◽  
Public Perceptions ◽  
Two Dimensions ◽  
Stereotype Content Model ◽  
Content Model ◽  
Stereotype Content ◽  
Two Factors ◽  
Destination Management Organizations ◽  
Additional Sample

This research proposes a measurement model to evaluate tourist stereotypes. Study 1 assesses the positive and negative tourist stereotypes that Hong Kong residents hold toward Chinese outbound tourists by connecting previous research on stereotypes from the Princeton Trilogy and from the stereotype content model. Six positive stereotypes were identified across two dimensions (i.e., Approachable: friendly, sincere, and good; and Competent: intelligent, industrious, and competent) as well as six inappropriate biases across two factors (i.e., Boastful: materialistic and loud; Rude: unreasonable, immoral, rude, and uncivilized). Study 2 provides further support for the measurement model by using an additional sample to investigate tourist self-stereotypes. Collectively, studies 1 and 2 contribute to the tourism literature by highlighting the dynamics involved in (self)-stereotyping that are relevant for destination management organizations (DMOs) and public policymakers involved in managing public perceptions of tourist stereotypes.

CALIBRATION OF SPECTRAL IRRADIANCE SOURCES USING A FIBER-COUPLED SYSTEM

2021 ◽  
Author(s):  
H.T.B Lee ◽  
Y.C. Chau ◽  
H.S.B. Lam
Keyword(s):  
Measurement Uncertainty ◽  
Light Source ◽  
Spectral Range ◽  
Coupled System ◽  
Measurement Model ◽  
Spectral Irradiance ◽  
Calibration Laboratory ◽  
Calibration Setup

The standards and Calibration Laboratory has recently developed the calibration service for the enclosed-type irradiance light source in the spectral range from 300 nm to 850 nm. The calibration is based on the source-based method measured by a fiber-coupled system. In this paper, the calibration setup, measurement model and the associated uncertainty are presented. The expanded measurement uncertainty is estimated to be less than 3,3 % over the measured spectral range which can support the needs from the testing and certification industry.

Digital Calibration for Current-Loop Output of Piezoresistive Sensors

2010 ◽  
Vol 143-144 ◽  
pp. 744-748
Author(s):  
Chao Yan ◽  
Jian Ning Ding ◽  
Zong Xing Li ◽  
Chao Min Mao
Keyword(s):  
Wide Temperature Range ◽  
Low Cost ◽  
Digital Calibration ◽  
Analog Signal ◽  
Current Loop ◽  
Calibration Process ◽  
Temperature Range ◽  
Piezoresistive Sensors

The precision of piezoresistive sensors is low between wide temperature range .The conditioning result isn’t ideal by analog approaches. Also the efficiency is very low. To improve this condition , a digital approach is introduced. It coverts sensors’ analog signal to digital value, and then uses polynomial and coefficients stored in singlechip to correct the digital value. At last , the singlechip coverts corrected digital value to analog signal to output. Its conditioning principle and calibration process is also described. We realized 4-to-20mA-current-loop-output of piezoresistive sensors using this aprroch. Calibration results show this method is efficient and low cost.

scholarly journals High-precision analysis of SF<sub>6</sub> at ambient level

2013 ◽  
Vol 6 (9) ◽  
pp. 2293-2299 ◽  
Author(s):  
J. S. Lim ◽  
D. M. Moon ◽  
J. S. Kim ◽  
W.-T. Yun ◽  
J. Lee
Keyword(s):  
United States Of America ◽  
Calibration Method ◽  
Gas Chromatograph ◽  
Activated Alumina ◽  
Calibration Laboratory ◽  
Working Standard ◽  
Calibration Methods ◽  
Precise Analysis ◽  
The World ◽  
Korea Research Institute

Abstract. This work reports on the development of a technique for the precise analysis of ambient SF6. This technique, which involves a gas chromatograph/electron capture detector (GC-ECD) coupled with an Activated Alumina-F1 (AA-F1) column, performed well in the measurements, particularly in terms of accuracy, which complies with the World Meteorological Organization (WMO)-recommended compatibility of 0.02 ppt. Compared to the Porapak Q technique, we observed a sharper peak shape for the SF6 stream, which substantiates the improvement in the analytical precision. The traceability to the WMO scale was tested by calibrating the GC-ECD/AA-F1 analyser using five SF6 standards provided by the WMO/Global Atmosphere Watch (GAW) Central Calibration Laboratory (CCL) for SF6 (NOAA, United States of America). After calibration by various methods, the GC-ECD/AA-F1 accurately estimated the mole fraction of SF6 in the working standard prepared by the World Calibration Centre for SF6 operated by the Korea Meteorological Administration (KMA)/Korea Research Institute of Standards and Science (KRISS). Among the calibration methods, the two-point calibration method emerged to be the most economical procedure in terms of the data quality and measurement time. It was found that the KRISS scale of SF6/N2 was biased by 0.13 ppt when compared to the WMO scale of SF6/air; this bias is probably due to a different matrix.

scholarly journals World Calibration Center for SF<sub>6</sub> – supporting the quality system of the global atmosphere observation

2012 ◽  
Vol 5 (5) ◽  
pp. 7899-7921
Author(s):  
J. Lee ◽  
D. Moon ◽  
D. Min ◽  
W. Yun
Keyword(s):  
Mole Fraction ◽  
Sulfur Hexafluoride ◽  
Primary Standard ◽  
Quality System ◽  
National Metrology Institute ◽  
Calibration Laboratory ◽  
Working Standard ◽  
Traceability Chain ◽  
Long Run ◽  
The World

Abstract. According to the World Meteorological Organization (WMO) Global Atmosphere Watch (GAW) Strategic Plan: 2008–2015 (WMO, 2009a) WMO/GAW pays attention to systematical improvement of the quality of observations at global or regional monitoring sites. To ensure the comparability and compatibility of the measurements worldwide it is essential to maintain a traceability chain to the primary standard in the different laboratories around the world as well as to establish a quality control system. Sulfur hexafluoride (SF6), is reported to be very rare in the atmosphere at the global averaged annual mole fraction of about 7 ppt, it is one of the greenhouse gases regulated by Kyoto protocol and is increasing at a rate of 0.22 ppt yr−1. Development of a working (or transfer) standard with very low concentration of SF6 requires expert technologies and several knowhow of gas metrology. In order to meet the Data Quality Objective (DQO), the KMA has cooperated with the Korea Research Institute of Standards and Science (KRISS), which is the National Metrology Institute in South Korea. So long as the Central Calibration Laboratory (CCL) for SF6 was established, the Korea Meteorological Administration (KMA) is now trying to take another step forward to systematically support GAW stations in improving their traceability and quality system for SF6, thereby making a contribution to the WMO/GAW. Through hosting the World Calibration Center for SF6, which is one of GAW facilities, KMA will contribute to harmonization of the global SF6 observations in the long run. This work performed to demonstrate some measurement results on SF6 which complies with the DQOs and is traceable to the WMO mole fraction scale for SF6. In order to produce a working standard which is traceable to the WMO scale, we developed highly precise method of a Gas Chromatography/Electron Capture Detector (GC/ECD) calibrated against the five cylinders (from NOAA, 2011) of the WMO scale. For all analysis the measurement repeatability was < 0.02 ppt (standard deviation) and analyzer's stability was controlled within a drift of 0.02 ppt. Finally, a working standard which is consistent with WMO scale and satisfies the WMO DQOs of ±0.02 ppt was successfully produced and is ready to be transferred to the GAW stations.

scholarly journals Two Mode DPM Equipped with an Automatic Leak Test Using MPX5050GP and MPXV4115VC6U Sensors

2021 ◽  
Vol 3 (1) ◽  
pp. 1-7
Author(s):  
Fita Florensa Rooswita ◽  
Triana Rahmawati ◽  
Syaifudin Syaifudin
Keyword(s):  
Negative Pressure ◽  
Digital Data ◽  
Average Error ◽  
Positive Pressure ◽  
Leak Test ◽  
Suction Pump ◽  
Calibration Process ◽  
Pressure Calibration ◽  
Measurement Results ◽  
Selection Of

The calibration process aims to guarantee measurement results in accordance with established standards. One of the tools used for pressure calibration is the Digital Presure Meter, which is the function of this tool to measure pressure on the Sphygmomanometer and Suction Pump or other tools that use pressure parameters for measurement. This module uses the Arduino system as a control and processing of analog data into digital data in order to condition the output of the MPX5050GP sensor for positive pressure and MPXV4115VC6U sensor for vacum pressure, this module uses a 4x20 LCD character display and there is a selection of mmHg and Kpa units with fluctuating resolution 0.25. Also in this module there is also an automatic leak test feature for the Sphygmomanometer, the measurement results obtained an average error of 7.3 mmHg for sphymomanometer measurements, and for suction pumps less than 1.5 Kpa. From these results it was concluded that this module can be used for the measurement of tools that use positive pressure and negative pressure.

Verocytotoxin-producing Escherichia coli infection: The Hong Kong experience

1998 ◽  
Vol 13 (11-s4) ◽  
pp. S289-S293 ◽  
Author(s):  
SSY WONG ◽  
WC YAM ◽  
PHM LEUNG ◽  
PCY WOO ◽  
KY YUEN
Keyword(s):  
Escherichia Coli ◽  
Hong Kong ◽  
Escherichia Coli Infection
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