Chemical Analysis of Coal by Energy Dispersive X-Ray Fluorescence Utilizing Artificial Standards

Abstract

Accurate determinations of the elemental composition of coal by classical methods can be quite difficult and are normally very time consuming. X-ray fluorescence utilizing the powder method, however, has the ability of providing accurate and rapid analyses. Unfortunately, well characterized standards, although available, are not plentiful. In addition, the durability or stability of ground and pelletized coal samples is poor resulting in deterioration with time. As a result, artificial coal standards were prepared from certified geological materials by fusing in lithium-tetra-borate in percentages approximating expected ash contents and compositions in coal. Since the lithium-tetra-borate comprises about the same percentage of the standard as does the carbon, hydrogen, and oxygen in coal, the ground and pelletized coal sample can be assayed against the fused calibration curves by compensating for the differences in the mass absorption coefficients of the two matrices.

Lingual Behavior in Clarinet Articulation: A Multiple-Case Study Into Single and Double Tonguing

“…This suggests that the success of ST in the altissimo register resulted from the fact that the tongue dorsum was unconstrained to freely lower during note production in the altissimo register. This finding that especially during the altissimo register, the vocal tract shape changes by lowering the tongue dorsum is consistent with the literature discussed in the introduction (Clinch et al, 1982; Fritz & Wolfe, 2005; Gardner & Stone, 2015; Lulich et al, 2017; Pamies-Vila et al, 2020; Scavone et al, 2008; Wheeler, 2010).…”

“…Especially in the altissimo register, the vocal tract shape changes (Fritz & Wolfe, 2005; Gardner & Stone, 2015) to provide enough inter-oral pressure to produce notes (Pamies-Vila et al, 2018; 2020; Scavone et al, 2008). X-ray fluoroscopic data (Clinch et al, 1982; Wheeler, 2010) and ultrasound data (Lulich et al, 2017) show that during non-articulated and portamento style playing, the tongue dorsum moves downward in the highest registers and upward in the lower registers in successful note productions, indicating that the players respectively enlarge and diminish the size of the oral cavity. Vocal tract shape in the lower regions seems to mainly affect the timbre of a note (Scavone et al, 2008).…”

Methods for sampling and inorganic analysis of coal

“…X-ray fluorescence (XRF) spectrometry is a rapid technique for accurate and precise elemental analysis of solid and liquid specimens. As such, it is suited to the determination of certain important elements that occur in coal and has been used extensively for the analysis of both whole coal and coal ash (Kuhn and others, 1975;Giauque and others, 1979;Mills and others, 1981;Wheeler, 1983). In practice, most XRF spectrometer systems are not able to detect elements having atomic numbers lower than 11, the atomic number of sodium.…”