Comparison of a two-wavelength pyrometer system and spectral pyrometry for high-temperature measurements.

A pyrometer system is an optically passive, non-intrusive method that uses thermal radiation law to determine temperature. It combines electronic and optical instruments to detect low-level signals of radiation measurements. Surface high-temperature measurements are successfully obtained using a two-wavelength pyrometer system. This study used a pyrometer system to achieve high stability, minimize errors due to changing emissivity, and remove background noise from the radiation measurement for surface high-temperature measurements. Temperature measurements were also obtained from Planck's model, and the results were compared with logarithmic assumption. The precision of these measurements is improved through variable optimization of the instruments, validation of the data, and calibration of the pyrometer system. The 16 temperature measurements were obtained (800-1600°C temperature measurement range) with a correlation coefficient above 97%. The response time between temperature readings is within 785 µs. Furthermore, the high-temperature measurements were obtained with higher stability (±2.99∘ C at 1600°C) and less error (less than 2.29% for Si sensor). In addition, the error of the temperature measurement was reduced from 5.33% to 0.86% at 850°C by using Planck's model compared with using logarithmic assumption. A cooling system temperature is also optimized to reduce the error temperature reading. It was found to be at 10°C that the uncertainty was reduced from 2.29% at ambient temperature to 1.53% at 1600°C. The spectral pyrometry system was also used in comparison with the two-wavelength pyrometer system to confirm that the calibration curves of the spectral pyrometry can be used to determine temperature measurements.

Qualitative Analysis of Dairy and Powder Milk Using Laser-Induced Breakdown Spectroscopy (LIBS).

Laser-induced breakdown spectroscopy (LIBS) technique was used to compare various types of commercial milk products. Laser-induced breakdown spectroscopy spectra were investigated for the determination of the elemental composition of soy and rice milk powder, dairy milk, and lactose-free dairy milk. The analysis was performed using radiative transitions. Atomic emissions from Ca, K, Na, and Mg lines observed in LIBS spectra of dairy milk were compared. In addition, proteins and fat level in milks can be determined using molecular emissions such as CN bands. Ca concentrations were calculated to be 2.165 ± 0.203 g/L in 1% of dairy milk fat samples and 2.809 ± 0.172 g/L in 2% of dairy milk fat samples using the standard addition method (SAM) with LIBS spectra. Univariate and multivariate statistical analysis methods showed that the contents of major mineral elements were higher in lactose-free dairy milk than those in dairy milk. The principal component analysis (PCA) method was used to discriminate four milk samples depending on their mineral elements concentration. In addition, proteins and fat level in dairy milks were determined using molecular emissions such as CN band. We applied partial least squares regression (PLSR) and simple linear regression (SLR) models to predict levels of milk fat in dairy milk samples. The PLSR model was successfully used to predict levels of milk fat in dairy milk sample with the relative accuracy (RA%) less than 6.62% using CN (0,0) band.

Evaluation of Optical Depths and Self-Absorption of Strontium and Aluminum Emission Lines in Laser-Induced Breakdown Spectroscopy (LIBS).

Laser-induced breakdown spectroscopy (LIBS) is a widely used laser spectroscopic technique in various fields, such as material science, forensic science, biological science, and the chemical and pharmaceutical industries. In most LIBS work, the analysis is performed using radiative transitions from atomic emissions. In this study, the plasma temperature and the product [Formula: see text] (the number density N and the absorption path length [Formula: see text]) were determined to evaluate the optical depths and the self-absorption of Sr and Al lines. A binary mixture of strontium nitrate and aluminum oxide was used as a sample, consisting of variety of different concentrations in powder form. Laser-induced breakdown spectroscopy spectra were collected by varying various parameters, such as laser energy, gate delay time, and gate width time to optimize the LIBS signals. Atomic emission from Sr and Al lines, as observed in the LIBS spectra of different sample compositions, was used to characterize the laser induced plasma and evaluate the optical depths and self-absorption of LIBS.

Comparative Study of Elemental Nutrients in Organic and Conventional Vegetables Using Laser-Induced Breakdown Spectroscopy (LIBS).

In this study, the laser-induced breakdown spectroscopy (LIBS) technique was used to identify and compare the presence of major nutrient elements in organic and conventional vegetables. Different parts of cauliflowers and broccolis were used as working samples. Laser-induced breakdown spectra from these samples were acquired at optimum values of laser energy, gate delay, and gate width. Both univariate and multivariate analyses were performed for the comparison of these organic and conventional vegetable flowers. Principal component analysis (PCA) was taken into account for multivariate analysis while for univariate analysis, the intensity of selected atomic lines of different elements and their intensity ratio with some reference lines of organic cauliflower and broccoli samples were compared with those of conventional ones. In addition, different parts of the cauliflower and broccoli were compared in terms of intensity and intensity ratio of elemental lines.

Study of atomic and molecular emission spectra of Sr by laser induced breakdown spectroscopy (LIBS).

Laser Induced Breakdown Spectroscopy (LIBS) is an ideal analytical technique for in situ analysis of elemental composition. We have performed a comparative study of the quantitative and qualitative analysis of atomic and molecular emission from LIBS spectra. In our experiments, a mixture of SrCl2 and Al2O3 in powder form was used as a sample. The atomic emission from Sr and molecular emission from SrCl and SrO observed in LIBS spectra were analyzed. The optimum laser energies, gate delays, and gate widths for selected atomic lines and molecular bands were determined from spectra recorded at various experimental parameters. These optimum experimental conditions were used to collect calibration data, and the calibration curves were used to predict the Sr concentration. Limits of detection (LODs) for selected atomic and molecular emission spectra were determined.