Listar Artículos por autor "Alvarez, M."
Mostrando ítems 1-8 de 8
-
A compton peak method for incident angle determination in XRF with annular excitation
Greaves, E. D.; Sajo Bohus, L.; Marcó, L.; Alvarez, M. (X-Ray Spectrometry, 1992)Established methods for measuring the incident angle related to XRF when radioisotope annular sources are involved are briefly discussed. As an alternative technique, a direct measurement of the incident angle from the ... -
Determination of trace elements in organic specimens by energy-dispersive x-ray fluorescence using a fundamental parameters method
Alvarez, M.; Mazo Gray, V. (Wiley Analytical Science, 1991)A rapid method for the simultaneous determination of trace elements in milk powder by energy-dispersive x-ray fluorescence has been developed. The measurement system consists of an Si(Li) detector, an x-ray tube coupled ... -
Determination of traces of heavy metals in estuarine waters of Barbacoas Bay, Colombia, by X-Ray fluorescence spectrometry
Mazo-Gray, V.; Sbriz, L.; Alvarez, M. (1998-12-04)An evaluation of metal contamination in estuarine waters and shrimp culture systems was conducted using two analytical processes: soluble metals were examined by radioisotope x-ray fluorescence spectrometry (RIXRF) and ... -
A low‐cost LN2 monitor
Alvarez, M.; Sbriz, L.; Cordero, M. (American Journal of Physics, 1989-10)This article describes a homemade LN2 monitor that same function at a much-reduced cost protecting detector systems against accidental warmup by monitoring the liquid level in the dewar and providing a visual warning of ... -
Mössbauer and X-ray fluorescence study of sediments from Samana Bay, Dominican Republic
Villagran, M.; Sbriz, L.; Alvarez, M. (Journal of Radioanalytical and Nuclear Chemistry, 1995-08)The chemical state of iron in sediments collected from Samana Bay has been determined by Mössbauer spectroscopy. The Mössbauer spectra were composed of two paramagnetic doulets, which correspond to high=spin ferric and ... -
Radioisotope X-ray fluorescence analysis of vanadium in petroleum coke samples
Alvarez, M.; Alvarado, J.; Cristiano, A. R.; Marcó, L. M.; Pérez, M. M. (Journal of Radioanalytical and Nuclear Chemistry, 1990)Radioisotope X-ray fluorescence spectrometry, RIXRF, was used for the determination of vanadium in Venezuelan petroleum coke samples using a simple standardless method and fundamental parameter approach. The values obtained ... -
Trace element determination of mercury by total-reflection X-ray fluorescence
Greaves, E.D.; Alfonso Sosa, J.; Sajo-Bohus, L.; Alvarez, M.; Wobrauschek, P.; Streli, Ch. (Spectrochimica Acta Part B: Atomic Spectroscopy, 1997-07-01)A rapid and simple method is presented for the determination of trace amounts of ionic mercury in solutions by total-reflection X-ray fluorescence. The method relies on the formation of a mercury amalgam on a 50 nm thick ... -
X-ray fluorescence characterization of ming-dynasty porcelain rescued from a spanish shipwreck
Mazo-Gray, V.; Alvarez, M. (wiley, 1992-02)A radioisotope induced X-ray fluorescence method was used to measure trace elements in Ming porcelain. Thirty pieces of blue-and-white Chinese porcelain, belonging to the Ch'eng Hua reign (AD 1465-87) and rescued from a ...