AN INVESTIGATION OF THE MACBETH ILLUMINOMETER

1948 ◽  
Vol 26f (2) ◽  
pp. 59-65 ◽  
Author(s):  
W. E. Knowles Middleton ◽  
A. R. Ramsey

The MacBeth illuminometer is a well known portable photometer of the visual type. Measurements of its errors show that the instrument gives reliable results if used with care. The most serious errors may occur when the color temperature of the light that is being measured differs greatly from that of the working standard lamp in the instrument. Under such conditions, different observers may obtain widely different results.

Author(s):  
E. M. El-Moghazy ◽  
F.M. EL-Sharkawy

Working standards for compact lamps is very important to some inspection organizations in Egypt.  We prepare the working standard lamp of high power compact lamp .These lamps provide the realization of luminous flux scale in the photometry laboratory in national institute for standard (NIS).  We choose three types of lamps in our study.  The lamp types are compact florescent lamp at nominal watt (WL1) 85watt, (WL2) at nominal Watt 105 Watt with ballast and (WL3) at nominal Watt 105watt without ballast.  The spectral power distributions of all the standard lamps and test lamps are measured.  The results of experimentally obtained values of luminous flux of each lamp type at the calibration values of supply voltage at 220 volts are illustrated.


2021 ◽  
Vol 31 (4) ◽  
pp. 102-109
Author(s):  
E. G. Silkis ◽  
◽  
A. S. Stankevich ◽  
V. N. Krasheninnikov ◽  
Yu. A. Repeev ◽  
...  

On the basis of mini-spectrometers, a reference lamp of the SIRSH type with a known color temperature, and line spectrum sources, an inexpensive hardware complex has been created for measuring the emission parameters of heterodiodes and interference filters. Examples of recording the emission of heterodiodes (full width at half maximum is 17–30 nm) with a maximum of emission in the region of 659 and 764 nm and measurement of an interference filter (FWHM of the bandwidth is 12 nm) with a maximum transmission of 727 nm are given. The emission parameters of the SIRSH standard lamp are introduced into the program for measuring and processing data, due to which it is possible to significantly refine the value of the wavelength of the maximum emission and transmission.


2019 ◽  
Vol 7 ◽  
Author(s):  
Zhiyu He ◽  
Guo Jia ◽  
Fan Zhang ◽  
Xiuguang Huang ◽  
Zhiheng Fang ◽  
...  

Although the streaked optical pyrometer (SOP) system has been widely adopted in shock temperature measurements, its reliability has always been of concern. Here, two calibrated Planckian radiators with different color temperatures were used to calibrate and verify the SOP system by comparing the two calibration standards using both multi-channel and single-channel methods. A high-color-temperature standard lamp and a multi-channel filter were specifically designed for the measurement system. To verify the reliability of the SOP system, the relative deviation between the measured data and the standard value of less than 5% was calibrated out, which demonstrates the reliability of the SOP system. Furthermore, a method to analyze the uncertainty and sensitivity of the SOP system is proposed. A series of laser-induced shock experiments were conducted at the ‘Shenguang-II’ laser facility to verify the reliability of the SOP system for temperature measurements at tens of thousands of kelvin. The measured temperature of the quartz in our experiments agreed fairly well with previous works, which serves as evidence for the reliability of the SOP system.


Metrologiya ◽  
2020 ◽  
pp. 16-24
Author(s):  
Alexandr D. Chikmarev

A single program has been developed to ensure that the final result of the data processing of the measurement calibration protocol is obtained under normal conditions. The calibration result contains a calibration function or a correction function in the form of a continuous sedate series and a calibration chart based on typical additive error probabilities. Solved the problem of the statistical treatment of the calibration protocol measuring in normal conditions within a single program “MMI–calibration 3.0” that includes identification of the calibration function in a continuous power series of indications of a measuring instrument and chart calibration. An example of solving the problem of calibration of the thermometer by the working standard of the 3rd grade with the help of the “MMI-calibration 3.0” program.


2020 ◽  
pp. 53-58
Author(s):  
A. V. Koudelny ◽  
I. M. Malay ◽  
V. A. Perepelkin ◽  
I. P. Chirkov

The possibility of using bolometric converters of microwave power from the State primary standard of the unit of power of electromagnetic waves in waveguide and coaxial paths GET 167-2017, which has a frequency range from 37,5 to 78,33 GHz, in an extended frequency range up to 220 GHz, is shown. Studies of semiconductor bolometric converters of microwave power in an extended frequency range have confirmed good agreement and smooth frequency characteristics of the effective efficiency factor of the converters. Based on the research results, the State working standard of the unit of power of electromagnetic waves of 0,1–10 mW in the frequency range from 37,5 to 220 GHz 3.1.ZZT.0288.2018 was approved. The technical characteristics of the working standard of the unit of power of electromagnetic oscillations in an extended frequency range from 37,5 to 220 GHz are given.


2020 ◽  
Vol 17 (5) ◽  
pp. 382-388
Author(s):  
Aparna Wadhwa ◽  
Faraat Ali ◽  
Sana Parveen ◽  
Robin Kumar ◽  
Gyanendra N. Singh

Objective: The main aim of the present work is to synthesize chloramphenicol impurity A (CLRMIMP- A) in the purest form and its subsequent characterization by using a panel of sophisticated analytical techniques (LC-MS, DSC, TGA, NMR, FTIR, HPLC, and CHNS) to provide as a reference standard mentioned in most of the international compendiums, including IP, BP, USP, and EP. The present synthetic procedure has not been disclosed anywhere in the prior art. Methods: A simple, cheaper, and new synthesis method was described for the preparation of CLRM-IMP-A. It was synthesized and characterized by FTIR, DSC, TGA, NMR (1H and 13C), LC-MS, CHNS, and HPLC. Results: CLRM-IMP-A present in drugs and dosage form can alter the therapeutic effects and adverse reaction of a drug considerably, it is mandatory to have a precise method for the estimation of impurities to safeguard the public health. Under these circumstances, the presence of CLRM-IMP-A in chloramphenicol (CLRM) requires strict quality control to satisfy the specified regulatory limit. The synthetic impurity obtained was in the pure form to provide a certified reference standard or working standard to stakeholders with defined potency. Conclusion: The present research describes a novel technique for the synthesis of pharmacopoeial impurity, which can help in checking/controlling the quality of the CLRM in the international markets.


Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4707
Author(s):  
Ching-Hua Chen ◽  
Jia-Jun Zhang ◽  
Chang-Han Wang ◽  
Yu-Chia Chang ◽  
Pinghui S. Yeh

Constant light power operation of an ultraviolet (UV) LED based on portable low-cost instrumentation and a monolithically integrated monitoring photodiode (MPD) has been reported for the first time. UV light irradiation has become one of the essential measures for disinfection and sterilization. Monitoring and maintaining a specified light power level is important to meet the criteria of sterilization. We built a module composed of a monolithically integrated UV LED and MPD, a transimpedance amplifier, an Arduino Uno card, a digital-to-analog converter and a Bluetooth transceiver. An Android App that we wrote remotely controlled the UV LED module via Bluetooth. The Arduino Uno card was programmed to receive demands from the smartphone, sent a driving voltage to the LED and returned the present MPD voltage to the smartphone. A feedback loop was used to adjust the LED voltage for maintaining a constant light output. We successfully demonstrated the functioning of remote control of the App, and the resultant UV LED measured power remained the same as the setting power. This setup can also be applied to visible or white LEDs for controlling/maintaining mixed light’s chromaticity coordinates or color temperature. With such controlling and internet capability, custom profiling and maintenance of precision lighting remotely would be possible.


Sign in / Sign up

Export Citation Format

Share Document