Brian Hart

Quantitative Chemical State XPS Analysis of First Row Transition Metals, Oxides and Hydroxides

Practical quantitative chemical state X-ray photoelectron spectroscopy (XPS) analysis of first row transition metals, oxides and hydroxides is challenging due to the complexity of their M 2p spectra. Complex multiplet splitting, shake-up and plasmon loss structure can play a role in the interpretation of the chemical states present. This paper will show practical curve fitting procedures for the quantitative measurement of different chemical states for metal oxides and hydroxides from a survey of transition metals. It will also discuss some of the limitations and pitfalls present as well as give practical examples of their successful use. These curve-fitting procedures are based on 1) standard spectra from quality reference samples, 2) a survey of appropriate literature databases and/or a compilation of literature references, 3) fitting of multiplet split spectra based on spectra of numerous reference materials and theoretical modelling, 4) spectral subtractions routines, again using reference spectra, and 5) specific literature references where fitting procedures are available.

Geochemistry and Mineralogy of Fly-Ash from the Mae Moh Lignite Deposit, Thailand

The concentration of 21 elements in fly ash from three boilers (75 MW, 150 MW and 300 MW) at the EGAT power plant, Mae Moh, Thailand, were determined by instrumental neutron activation analysis (INAA). The concentration of 10 major elements was determined by x-ray fluorescence (XRF). Arsenic, Co, Cr, Ni, Mo and Sb generally increase in concentration going from bottom ash (BA) through the sequence of electrostatic precipitator ashes (ESPA) and reach maxima of As (352 ppm), Co (45 ppm), Cr (105) ppm, Mo (32 ppm), Ni (106 ppm) and Sb (15 ppm) in the ESPA. Cerium, Cs, Fe, Hf, La, Sc, Ta, Tb and Yb did not exhibit concentration trends or are variable except in the case of one boiler (unit 6), which showed an increase going from BA to ESPA. Only Br decreased in composition going from BA to ESPA. Rubidium, Sm, U and Th showed marked variation in trends. Scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS) was used to identify element assemblages within discrete particles and particl...

Study relationship between inorganic and organic coal analysis with gross calorific value by multiple regression and ANFIS

The relationship between maceral content plus mineral matter and gross calorific value (GCV) for a wide range of West Virginia coal samples (from 6518 to 15330 BTU/lb; 15.16 to 35.66 MJ/kg) has been investigated by multivariable regression and adaptive neuro-fuzzy inference system (ANFIS). The stepwise least square mathematical method comparison between liptinite, vitrinite, plus mineral matter as input data sets with measured GCV reported a nonlinear correlation coefficient (R 2) of 0.83. Using the same data set the correlation between the predicted GCV from the ANFIS model and the actual GCV reported a R 2 value of 0.96. It was determined that the GCV-based prediction methods, as used in this article, can provide a reasonable estimation of GCV.

A global crisis: Energy in the future

We are beginning to consider the concept of sustainable (renewable) energy when we develop new technologies. Our present technologies are not sustainable. We are living on capital. Given that one hour of sunlight could provide our annual needs for one year, the future must be with solar energy. Geothermal energy sources, using the normal thermal gradient of Earth, are also impressive. There is no sign thatHomo sapiens has the wisdom to use fission energy given the potential abuses of this technology. One thing is certain, if we continue to burn fossil carbon to supply the worlds increasing energy demands, the consequences will be devastating for all life.