Development of a Drift-Correction Procedure for a Photoelectric Spectrometer

1978 ◽  
Vol 32 (1) ◽  
pp. 46-53 ◽  
Author(s):  
Gilbert B. Chapman ◽  
William A. Gordon
Keyword(s):  
Optical Path ◽  
Automatic Correction ◽  
Sample Analysis ◽  
Electronic Components ◽  
Drift Correction ◽  
Direct Reading ◽  
Coefficients Of Variation ◽  
Lamp Current ◽  
Analytical Calibration ◽  
Correction System

This procedure provides automatic correction for drifts in the radiometric sensitivity of each detector channel in a direct-reading emission spectrometer. Such drifts are customarily controlled by the regular analyses of standards, which provide corrections for changes in the excitational, optical, and electronic components of the instrument. This standardization procedure, however, corrects for the optical and electronic drifts, thus minimizing the time, effort, and cost of regularly processing standards. This method of radiometric drift correction uses a 1000-W tungsten-halogen reference lamp to illuminate each detector through the same optical path as that traversed during sample analysis. The responses of the detector channels to this reference light are regularly compared with channel responses to the same light intensity at the time of analytical calibration in order to determine and correct for drift. The coefficients of variation of these drift corrections average less than 1%. Except for placing the lamp in position, the procedure is fully automated and compensates for changes in spectral intensity due to variations in lamp current. A discussion of the implementation of this drift-correction system is included.

scholarly journals Automatic Correction of Arabic Dyslexic Text

Computers ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 19 ◽  
Author(s):  
Maha Alamri ◽  
William Teahan
Keyword(s):  
Word Processing ◽  
Language Model ◽  
Text Compression ◽  
Arabic Text ◽  
Automatic Correction ◽  
Compression Scheme ◽  
Candidate List ◽  
Arabic Word ◽  
Processing Software ◽  
Correction System

This paper proposes an automatic correction system that detects and corrects dyslexic errors in Arabic text. The system uses a language model based on the Prediction by Partial Matching (PPM) text compression scheme that generates possible alternatives for each misspelled word. Furthermore, the generated candidate list is based on edit operations (insertion, deletion, substitution and transposition), and the correct alternative for each misspelled word is chosen on the basis of the compression codelength of the trigram. The system is compared with widely-used Arabic word processing software and the Farasa tool. The system provided good results compared with the other tools, with a recall of 43%, precision 89%, F1 58% and accuracy 81%.

System of Automatic Correction and Measurement for Hypoid Gears

2011 ◽  
Vol 464 ◽  
pp. 155-158 ◽  
Author(s):  
Tian Xing Li ◽  
Xiao Zhong Deng ◽  
Zhen Shan Gao ◽  
Ju Bo Li
Keyword(s):  
Closed Loop ◽  
Tooth Surface ◽  
Milling Machine ◽  
Automatic Correction ◽  
Hypoid Gears ◽  
Surface Deviation ◽  
Deviation Measurement ◽  
The Stability ◽  
Surface Precision ◽  
Correction System

The system of automatic correction and deviation measurement of hypoid gears is the basic platform for the digital closed-loop manufacturing technology. Based on the gear measuring center and the numerical controlled gear milling machine, a measurement and correction system is developed by the application of Visual C++ and Fortran. The architecture and the implement of the main modules are elaborated. Experiments and applications indicate that the tooth surface deviation can be effectively reduced by the system of automatic correction and measurement, and the stability of tooth surface precision and manufacturing quality is improved. It would provide the foundation for the digitalization of manufacture and quality control of hypoid gears.

Atomic Line Profiles in Hollow Cathode Lamps and a Glow Discharge Atomizer Determined by Fourier Transform Spectroscopy

1995 ◽  
Vol 49 (7) ◽  
pp. 927-938 ◽  
Author(s):  
Victor Pavski ◽  
Chuni L. Chakrabarti
Keyword(s):  
Glow Discharge ◽  
Hollow Cathode ◽  
Dynamic Range ◽  
Kinetic Temperature ◽  
Line Profiles ◽  
Linear Dynamic Range ◽  
Linear Dynamic ◽  
Lamp Current ◽  
Analytical Calibration ◽  
Atomic Lines

In an attempt to understand the implications of using glow discharge atomizers in atomic absorption spectrometry (AAS), line profiles and kinetic (Doppler) temperatures were measured in commercial hollow cathode lamps and a laboratory-constructed, jet-assisted dc glow discharge atomizer using a high-resolution Bomem Fourier transform spectrometer. Line profiles were measured in the hollow cathode lamps as current was increased from 1 to 30 mA for three resonance atomic lines (Mg 285.21 nm, Al 308.22 nm, and Pb 283.31 nm) having distinctly different hyperfine structure. Although the Al 308.22-nm line was largely unaffected by self-absorption as the lamp current was increased, the Pb 283.31-nm and Mg 285.21-nm lines exhibited pronounced self-absorption broadening at relatively low lamp currents. Kinetic temperatures in the hollow cathode lamps ranged from 320 ± 20 K at low lamp currents to 840 ± 20 K at high currents. With the use of the Ar(I) 415.86-nm line from the argon discharge gas as a thermometric species, kinetic temperatures of 460 ± 20 K to 620 ± 20 K were measured in the glow discharge atomizer under typical analytical operating conditions. These low atomizer gas temperatures imply that the sensitivity and linear dynamic range of analytical calibration curves will be more strongly affected by the lamp current of the primary radiation source and the spectral properties of the analysis line in glow discharge AAS than in flame or furnace AAS, and that operation at low lamp current is essential for optimal analytical performance. The degrees to which the linear dynamic range and the slope of the analytical calibration curve would be affected by the hyperfine structure of the analysis line, the extent of self-absorption in the hollow cathode lamp, the hollow cathode kinetic temperature, and the glow discharge kinetic temperature are considered separately for each atomic line investigated. The kinetic temperatures in the hollow cathode lamps and the glow discharge atomizer were so close that it was possible to obtain absorption line profiles for the three resonance atomic lines in the glow discharge atomizer with the use of hollow cathode lamps as primary radiation sources, i.e., without the necessity of using a continuum source of radiation.

scholarly journals Internal Standard-based Analytical Method for Tobacco Smoke Vapor Phase Components

1999 ◽  
Vol 18 (4) ◽  
pp. 131-146
Author(s):  
F Omori ◽  
N Higashi ◽  
M Chida ◽  
Y Sone ◽  
S Suhara
Keyword(s):  
Vapor Phase ◽  
Multivariate Analyses ◽  
Internal Standard ◽  
Mainstream Smoke ◽  
Gas Chromatograph ◽  
Sample Analysis ◽  
Injection Device ◽  
Mixed Gas ◽  
Continuous Component ◽  
Coefficients Of Variation

AbstractWe developed an internal standard-based method to analyze the vapor phase components of mainstream smoke. This method collects vapor phase components from sample cigarettes, which are smoked by a linear automatic smoking machine in a sampling bag. An internal standard gas was introduced to the bag. A 6-port valve with a 2-ml sampling loop was placed between the vapor phase smoke outlet of the smoking machine and the bag to regulate the volume of the internal standard. The mixed gas sample was then introduced, by an automatic injection device developed in-house, to a gas chromatograph (GC) for ten successive analyses. The sample in the bag was analyzed every two hours to assess the time serial changes of vapor phase smoke components as well as of the internal standard. After 18 hours, in the tenth analysis, the amounts of 37 vapor phase components decreased by less than 5 % from those in the first analysis. The repeatability of the sample analysis was assessed and 45 vapor phase components had coefficients of variation of less than 5 %. The overall reproducibility of this method including tobacco samples and instruments was also assessed using five other sampling bags and achieved coefficients of variation of less than 6 % for 42 vapor phase components. The advantages of this method include capability to handle 10 tobacco samples in a serial manner, capability to collect both the vapor phase and semivolatile components, and precise, easy and continuous component analyses. We also present the results of multivariate analyses for the vapor phase and semivolatile components from 59 sample cigarettes.

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