Material: Silicate

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2 articles found

Quantitative Analysis of Trace O Concentration in SF6 with Laser-Induced BreakdownSpectroscopy

Author: Yang, W. ; et. al.

Journal: Spectroscopy and Spectral Analysis (2017)

Fundamentals Applications Chemometrics

DOI: 10.3964/j.issn.1000-0593(2017)12-3865-06

Authors
Li, B. C.

Keywords

Laser-induced breakdown spectroscopy; SF6 oxygen concentration; Wavelet transform; Partial least square; Quantitative analysis;DISCHARGE

Abstract

Sulfur hexafluoride (SF6) is widely used in gas-insulated high-voltage equipments due to its excellent insulation and arc extinguishing performance. However, when impurities such as trace water and oxygen are present in SF6, the by-products, which are formed due to equipment faults and partial discharge, can react with these impuriti to form stable sulfur oxyfluorides. The equipment insulation performance can be degraded significantly by those stable sulfur oxyfluorides, causing threat to the safety of the power system. The detection and analysis of the impurities such as water, oxygen and decompositions in SF6 are therefore of great importance. In this paper, laser-induced breakdown spectroscopy is employed to measure trace O in SF6. CaF2 is used as window material to solve the degradation of the excitation energy caused by the corrosion of the window material by SF6 decompositions, to eliminate the pollution problem caused by the reaction between the window material and the breakdown products of SF6 gas, and to reduce the change of plasma state caused by the change of excitation condition. By correcting the spectral baseline with an iterative wavelet transform and suppressing the noise with a wavelet transform with soft thresholding, a limit of detection of 38ppm is achieved from the experimental calibration curve. Furthermore, a quantitative model based on partial least squares (PLS) is developed to achieve better stability and precision.

Area:

Geology

Material:

Silicate

Elements:

Emmision lines:

Geochemical Fingerprinting by Handheld Laser-Induced Breakdown Spectroscopy

Author: Harmon, R. S. ; et. al.

Journal: Geostandards and Geoanalytical Research (2017)

Applications Chemometrics

DOI: 10.1111/ggr.12175

Authors
Collins, L. M. ; Hark, R. R. ; Rankey, E. C. ; Somers, A. M. ; Throckmorton, C. S. ; Wise, M. A.

Keywords

laser-induced breakdown spectroscopy; real-time chemical analysis; geochemical fingerprinting; stratigraphic correlation; provenance determination; mineral exploration;PARTIAL LEAST-SQUARES; DIAMOND EXPLORATION; GOLD MINERALIZATION; YUKON-TERRITORY; SOLID-SOLUTIONS; TRACE-ELEMENTS; RAPID ANALYSIS; ICP-MS; MINERALS; GARNET

Abstract

A broad suite of geological materials was studied a using a handheld laser-induced breakdown spectroscopy (LIBS) instrument. Because LIBS is simultaneously sensitive to all elements, the full broadband emission spectrum recorded from a single laser shot provides a chemical fingerprint' of any material - solid, liquid or gas. The distinguishing chemical characteristics of the samples analysed were identified through principal component analysis (PCA), which demonstrates how this technique for statistical analysis can be used to identify spectral differences between similar sample types based on minor and trace constituents. Partial least squares discriminant analysis (PLSDA) was used to distinguish and classify the materials, with excellent discrimination achieved for all sample types. This study illustrates through four examples (carbonate minerals and rocks, the oxide mineral pair columbite-tantalite, the silicate mineral garnet and native gold) how portable, handheld LIBS analysers can be used for real-time chemical analysis under simulated field conditions for element or mineral identification, plus such applications as stratigraphic correlation, provenance determination and natural resource exploration.

Area:

Geology

Material:

Carbonate ; Silicate

Elements:

Lines [nm]:

Ca II 315.89 nm Ca II 317.93 nm Ca II 393.37 nm Ca II 396.85 nm Ca I 442.54 nm Ca I 443.57 nm Ca I 445.48 nm Ca I 526.56 nm Ca I 527.03 nm Ca I 558.20 nm Ca I 558.88 nm Ca I 559.01 nm Ca I 559.85 nm Ca I 585.75 nm Ca I 610.27 nm Ca I 612.22 nm Ca I 616.13 nm Ca I 643.91 nm Ca I 646.26 nm Ca I 649.38 nm

Lines [nm]:

Au I 242.80 nm Au I 267.60 nm Au I 312.28 nm Au I 406.51 nm Au I 479.26 nm Au I 523.03 nm Au I 583.74 nm Au I 586.29 nm Au I 595.70 nm Au I 627.82 nm

Lines [nm]:

Mg II 279.55 nm Mg II 280.27 nm Mg I 285.21 nm Mg I 383.23 nm Mg I 383.83 nm Mg II 448.11 nm Mg I 516.73 nm Mg I 517.27 nm Mg I 518.36 nm

Lines [nm]:

Mn II 257.61 nm Mn II 259.37 nm Mn II 260.57 nm Mn I 279.48 nm Mn I 279.83 nm Mn I 403.08 nm Mn I 403.31 nm

Lines [nm]:

Ag II 241.32 nm Ag II 243.78 nm Ag I 546.55 nm Ag I 520.91 nm Ag I 328.07 nm Ag I 338.29 nm

...

Emmision lines:
Ta II 240.06 nm
Ag II 241.32 nm
Au I 242.80 nm
Ag II 243.78 nm
Mn II 257.61 nm
Mn II 259.37 nm
Mn II 260.57 nm
Au I 267.60 nm
Mn I 279.48 nm
Mg II 279.55 nm
Mn I 279.83 nm
Mg II 280.27 nm
Mg I 285.21 nm
Ta II 301.25 nm
Au I 312.28 nm
Be II 313.04 nm
Ca II 315.89 nm
Ca II 317.93 nm
Ag I 328.07 nm
Ag I 338.29 nm
Mg I 383.23 nm
Mg I 383.83 nm
Ca II 393.37 nm
Al I 394.40 nm
Al I 396.15 nm
Ca II 396.85 nm
Mn I 403.08 nm
Mn I 403.31 nm
Au I 406.51 nm
Ca I 442.54 nm
Ca I 443.57 nm
Ca I 445.48 nm
Mg II 448.11 nm
Au I 479.26 nm
Mg I 516.73 nm
Mg I 517.27 nm
Mg I 518.36 nm
Ag I 520.91 nm
Au I 523.03 nm
Ca I 526.56 nm
Ca I 527.03 nm
Ag I 546.55 nm
Ca I 558.20 nm
Ca I 558.88 nm
Ca I 559.01 nm
Ca I 559.85 nm
Au I 583.74 nm
Ca I 585.75 nm
Au I 586.29 nm
Na I 589.00 nm
Na I 589.59 nm
Au I 595.70 nm
Ca I 610.27 nm
Li I 610.35 nm
Ca I 612.22 nm
Ca I 616.13 nm
Au I 627.82 nm
Ca I 643.91 nm
Ca I 646.26 nm
Ca I 649.38 nm
H I 656.27 nm
Li I 670.78 nm

Material: Silicate

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