Effect of Plasma Gas and the Pressure on Spatially and Temporally Resolved Images of Copper Emission Lines in Laser Induced Plasma Optical Emission Spectrometry.

This paper investigated two-dimensional spatial and temporal images of a copper emission line in laser-induced breakdown spectroscopy (LIBS), in order to clarify the excitation/de-excitation processes occurring in a laser-induced plasma. The measurements were carried out under different plasma gases (argon, krypton, helium, and nitrogen), pressure levels (100 - 900 Pa) and delay times (100 - 1000 ns) with the aim of monitoring their effects on the behavior of the copper emission. Depending on the plasma gas type and the pressure level, large differences were found in the plasma shape and temporal intensity evolution of the copper emission profile.

Quantitative Analysis of Hydrogen in High-Hydrogen-Content Material of Magnesium Hydride via Laser-Induced Breakdown Spectroscopy.

An analytical approach that can rapidly determine a wide range of hydrogen concentration in solid-state materials has been recently demanded to contribute to the hydrogen economy. This study presents a method for estimating hydrogen concentrations ranging from 0.2 to 7.

Uncertainty of the Analytical Values in Laser-induced Plasma Optical Emission Spectrometry for Element-based Sorting of Commercial Aluminum Alloys.

This paper describes uncertainty ranges of the analytical values by laser-induced breakdown spectrometry (LIBS), in order to realize an element-based sorting of commercial Al alloys whose chemical compositions are varied depending on the kind. For this purpose, calibration factors and their standard errors between the emission intensity and the content of major alloyed elements were estimated using a series of standard reference materials of Al alloys. From the result of LIBS analysis, Al alloy samples, labeled as A1050, A1100, A2017, A2024, A5052, A5083, and A6061, were actually classified into the kinds of Al alloy for which the chemical compositions have been standardized by the Japanese Industrial Standards.

Fundamental Study on Ablation Sampling of Fe-based Binary Alloys in Laser-induced Breakdown Optical Emission Spectrometry.

This paper describes the fundamental process of laser ablation occurring in a laser-induced plasma. The sampling process in laser-induced breakdown plasma spectrometry is very complicated and thus has not been fully understood. Our study focused on a relationship between the composition of ablation amounts and the bulk composition, when Fe-based binary alloys were employed as test samples.

Characteristics of the calibration curves of copper for the rapid sorting of steel scrap by means of laser-induced breakdown spectroscopy under ambient air atmospheres.

For the rapid and precise sorting of steel scrap with relatively high contents of copper, laser-induced breakdown spectroscopy (LIBS) is a promising method. It has several advantages such that it can work under ambient air atmospheres, and specimens can be tested without any pretreatment, such as acid digestion, polishing of the surface of the specimens, etc. For the application of LIBS for actual steel scrap, we obtained emission spectra by an LIBS system, which was mainly comprised of an Nd:YAG laser, an Echelle-type spectrometer, and an ICCD detector.

Dissolution behavior of selenium from coal fly ash particles for the development of an acid-washing process.

Coal fly ash emitted from coal-fired electric power stations generally contains environmentally regulated trace elements. In particular, boron, arsenic, and selenium have been recognized as troublesome trace elements because elutions from the fly ash contain them. In order to design an effective removal process for these trace elements, we have developed and investigated an acid-washing process.

Analysis of atomic scale chemical environments of boron in coal by 11B solid state NMR.

Atomic scale chemical environments of boron in coal has been studied by solid state NMR spectroscopy including magic angle spinning (MAS), satellite transition magic angle spinning (STMAS), and cross-polarization magic angle spinning (CPMAS). The (11)B NMR spectra can be briefly classified according to the degree of coalification. On the (11)B NMR spectra of lignite, bituminous, and sub-bituminous coals (carbon content of 70-90mass%), three sites assigned to four-coordinate boron ([4])B with small quadrupolar coupling constants (≤0.

Removal of arsenic in coal fly ash by acid washing process using dilute H2SO4 solvent.

Coal fly ash emitted from coal thermal power plants generally contains tens ppm of arsenic, one of the hazardous elements in coal, during combustion and their elution to soil or water has become a public concern. In this study, the acid washing process developed by the authors was applied to the removal of arsenic from coal fly ash. Laboratory- and bench-scale investigations on the dissolution behavior of arsenic from various coal fly ash samples into dilute H(2)SO(4) were conducted.

Chemical state of boron in coal fly ash investigated by focused-ion-beam time-of-flight secondary ion mass spectrometry (FIB-TOF-SIMS) and satellite-transition magic angle spinning nuclear magnetic resonance (STMAS NMR).

The chemical states of boron in coal fly ash, which may control its leaching into the environment, were investigated by focused-ion-beam time-of-flight secondary ion mass spectrometry (FIB-TOF-SIMS) and satellite-transition magic angle spinning nuclear magnetic resonance (STMAS NMR) spectroscopy. The distribution of boron on the surface and in the interior of micron-sized fly ash particles was directly observed by FIB-TOF-SIMS. Coordination numbers of boron and its bonding with different atoms from particles of bulk samples were investigated by STMAS NMR.