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Determination of trace elements in petroleum by neutron activation analysis

I. Determination of Na, S, Cl, K, Ca, V, Mn, Cu, Ga and Br

Journal of Radioanalytical and Nuclear Chemistry
Authors:
K. Shah
,
R. Filby
, and
W. Haller

Abstract  

Using thermal neutron activation and a large-volume high-resolution Ge(Li) γ-ray spectrometer, the feasibility of the determination of the concentrations of Na, S, Cl, K, Ca, V, Mn, Cu, Ga, and Br in crude oils has been demonstrated. This instrumental method, which requires neither a chemical separation technique nor pre-concentration or post-concentration of trace elements by ashing, eliminates many inherent errors associated with chemical determination. The method is sensitive, precise and suitable for routine analysis. Fast neutron (n, p) and (n, α) reactions do not appreciably interfere and where necessary corrections may be applied. Loss of volatile elements, e.g. chlorine and bromine, due to recoil during irradiation is negligible.

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Determination of trace elements in petroleum by neutron activation analysis

II. Determination of Sc, Cr, Fe, Co, Ni, Zn, As, Se, Sb, Eu, Au, Hg and U

Journal of Radioanalytical and Nuclear Chemistry
Authors:
K. Shah
,
R. Filby
, and
W. Haller

Abstract  

Instrumental neutron activation analysis (INAA) and Ge(Li) spectrometry have been used to determine Sc, Cr, Fe, Co, Ni, Zn, As, Se, Sb, Eu, Au, Hg, and U in crude petroleum. The technique involves no chemical separations and no pre-concentration of the samples by ashing is necessary, thus avoiding contamination or loss of volatile elements. The estimated detection limits in ppb for the elements are Sc (0.1), Cr (0.16), Fe (400.0), Co (0.6), Ni (1.1), Zn (200.0), As (6.0), Se (23.0), Sb (1.0), Eu (0.58), Au (0.11), Hg (4.3), U (1.5). Precision values ranged from 0.1% to 15% (relative standard deviation). Interferences in the Co and Fe determinations due to fast neutron reactions (n, p) and (n, α) on Ni isotopes are small and are easily corrected. Losses of As, Se, and Hg due to escape of volatile gases during irradiation are negligible

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Abstract  

Neutron activation analysis and Ge(Li) spectroscopy was used to determine 32 elements in seven U.S.G.S. standard rocks of a wide range of composition. Short half-life nuclides (10 sec-10 min) were used to measure Sc, Hf, Dy, Mg, Al, Ca, Ti, V (and Na) in an automated rabbit Ge(Li) detector system. The elements K, Cu, Zn, Ga, Sr, Ba, La, Eu, Sm (and Mn) were determined by dissolution of the irradiated sample followed by removal of24Na on hydrated antimony pentoxide (HAP). Long-lived nuclides were used to measure Sc, Cr, Fe, Co, Zr, Rb, Sb, Cs, Ba, Ce, Eu, Yb, Tb, Lu, Hf, Ta and Th after decay of24Na. The method involves little radiochemistry and the separation is selective for24Na under the experimental conditions used. Elemental concentrations determined agree well with previously published data.

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Abstract  

Various in-situ gamma-spectroscopy applications need a versatile, multi-purpose, portable multi-channel analyzer (MCA). Recently, Canberra has introduced the Inspector-2000 for this purpose. It uses digital signal processing (DSP) technology and weighs only about 1.2 kg. It also supports CdTe, NaI and Ge detectors. Due to its use of DSP technology, the Inspector-2000 also provides a longer battery life, a better detector resolution and a better temperature stability than most portable MCAs. This paper includes a short description of the Inspector-2000 MCA and its performance characteristics compared to an analog MCA.

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Scientometrics
Authors:
G. Derrick
,
H. Sturk
,
A. Haynes
,
S. Chapman
, and
W. Hall

Abstract  

Reliability of citation searches is a cornerstone of bibliometric research. The authors compare simultaneous search returns at two sites to demonstrate discrepancies that can occur as a result of differences in institutional subscriptions to the Web of Science and Web of Knowledge. Such discrepancies may have significant implications for the reliability of bibliometric research in general, but also for the calculation of individual and group indices used for promotion and funding decisions. The authors caution care when describing the methods used in bibliometric analysis and when evaluating researchers from different institutions. In both situations a description of the specific databases used would enable greater reliability.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
S. P. LaMont
,
T. R. LaBone
,
J. R. Cadieux
,
W. M. Findley
,
G. Hall
,
C. R. Shick
,
D. W. Efurd
, and
R. E. Steiner

Summary  

The lung dissolution rates for PuO2 were determined using a 100 day in vitro experiment. A very small amount of the PuO2 rapidly dissolved with a half-time of approximately 10 days, while the majority of the material (>99%) dissolved with a half-time of approximately 5 . 105 days. This dissolution half time is significantly longer than what is recommended by the ICRP, and would result in higher calculated doses for inhalation intakes of PuO2 than those currently estimated by the ICRP 66 human respiratory tract model for radiological protection.

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