Search Results

You are looking at 1 - 10 of 11 items for

  • Author or Editor: D. Ryan x
Clear All Modify Search

Abstract  

Phosphorus is selectively extracted as molybdovanadophosphoric acid (MVPA) and determined indirectly using52V. Silicon, germanium, arsenic, fluoride and tannic acid do not interfere. The sensitivity for phosphorus was 1421±13 counts52V per ng P ml–1 with a detection limit of 0.2 ng P ml–1. The precision is ±10% over the range 0.7±70 ng P ml–1. The sensitivity is four orders of magnitude greater than for conventional neutron activation analysis (NAA) using the31P(n, )28 Al reaction and a SLOWPOKE II reactor. Greater selectivity for phosphorus is obtained than by direct measurement of32P by beta ray spectroscopy.

Restricted access

Abstract  

The dependence of self-absorption of X-rays and low energy -rays on energy and sample matrix has been studied for94mNb,128I,104mRh,239U and233Th. Experimentally determined attenuation factors have been compared to calculated values. The use of these nuclides in the instrumental neutron activation of practical samples has been evaluated.

Restricted access

Abstract  

An instrumental neutron activation analysis procedure has been developed which permits the direct determination of Au, Ir, Os and Rh in iron meteorites using a SLOWPOKE reactor. A simple correction method enables the instrumental determination of rhodium using its short-lived nuclide.

Restricted access

Abstract  

X-rays emitted by thallium and bismuth after neutron activation have been examined for their use in the determination of these elements. Interferences have been assessed. Thallium-204,206Tl and210Bi are employed. Detection limits are high but purely instrumental determinations are possible from 50 g per g to fractions of percent levels.

Restricted access

Abstract  

Lead phosphate quantitatively coprecipitates trace amounts of Ag(I), Cd(II), Cr(III), Cu(II), Mn(II), Th(IV), U(VI) and Zr(IV). The trace elements are determined in the precipitate by instrumental neutron activation analysis (INAA); detection limits are given. The practical application to the determination of U and Th is described.

Restricted access

Abstract  

Classical activation analysis of fluorine by thermal neutrons has a limited application because of frequent interference from chlorine, the short half life20F (11.4 s) and too high dead time of detectors. A procedure is described for fluorine determination using19F (n,p)19O reaction. Use of a boron carbide shield has no effect on the activity of19O (boron ratio −1) but considerably reduces background and interference due to18O (n, γ)19O reaction. The technique has been successfully applied to the determination of fluorine in organic compounds even in the presence of large amounts of chlorine and oxygen.

Restricted access

Abstract  

Hair samples from Canada, China, India and New Zealand were analyzed by neutron activation analysis. Comparison of the percent manganese in the alkali-soluble fraction of hair with the total manganese concentrations shows that, within groups, the percent manganese concentrations is relatively constant whereas overall concentrations are not. For multiple sclerosis (MS) patients, from Canada and New Zealand, very highly significant differences were observed, between controls and patients, for %Mn in the alkali-soluble fraction.

Restricted access

A novel instrument is described called the Thin film Analyser (TFA) which quantitatively measures changes in mechanical and rheological properties of drying films in-situ on a test panel. It is based around a simple force-sensing device, capable of carrying various probes, which can be positioned in anX-Y plane over the panel. Temperature control is achieved by means of a heating block under the sample. By imposing a thermal gradient along the block, measurements can be obtained at a series of temperatures in a single experiment. Several applications of the TFA to the drying of curable and latex-based coatings are discussed, as well as some more specialized uses. The TFA concept represents a novel approach to the thermal analysis of thin films.

Restricted access

Abstract

Research productivity affects the careers of academic psychologists. Unfortunately, there is a surprising lack of consensus on productivity's meaning, measurement, and how to compare the productivity of one academic psychologist to another. In the present study, we review academic productivity research within psychology, and using a sample of 673 psychologists, compute six indexes of productivity. Most productivity metrics (publication count, citation count, or some combination of the two) were substantially interrelated and one (Integrated Research Productivity Index) was independent from years in the field. Female psychologists were equally as productive as male psychologists after accounting for years in the field, and pre-tenure psychologists showed steeper change-over-time productivity slopes than post-tenure psychologists. Based on these findings, we provide recommendations for the use and measurement of academic research productivity.

Restricted access

Background

Internet gaming disorder (IGD) was introduced in the DSM-5 as a way of identifying and diagnosing problematic video game play. However, the use of the diagnosis is constrained, as it shares criteria with other addictive orders (e.g., pathological gambling).

Aims

Further work is required to better understand IGD. One potential avenue of investigation is IGD’s relationship to the primary reinforcing behavioral functions. This study explores the relationship between duration of video game play and the reinforcing behavioral functions that may motivate or maintain video gaming.

Methods

A total of 499 video game players began the online survey, with complete data from 453 participants (85% white and 28% female), were analyzed. Individuals were placed into five groups based on self-reported hours of video gaming per week, and completed the Video Game Functional Assessment – Revised (VGFA-R).

Results

The results demonstrated the escape and social attention function were significant in predicting duration of video game play, whereas sensory and tangible were not significant.

Conclusion

Future implications of the VGFA-R and behaviorally based research are discussed.

Open access