South African Bureau Of Standards Research Articles

The Applicability of the South African Visual Grading Rules to MalawianPinus patulaTimber

SYNOPSIS This paper investigates whether the new South African visual grading rules can be used to grade Malawian Pinus patula. Malawian Pinus patula was visually graded to the revised South African softwood visual grading rules for V5, V7 and V10. Three different sizes of timber, namely 50 x 75,50 x 100 and 50 x 150 mm were sampled. The visually graded timber was examined for correct grading by an inspector from the South African Bureau of Standards. All test specimens were trucked to the University of Pretoria where they were tested for bending, compression and tension strength. The results of the investigation are presented and discussed. Malawian Pinus patula appears to be superior to South African pine when visually graded to the South African visual grading rules. Although the number of specimens was limited, the authors feel that it would be safe to adopt the South African rules even though they penalise the Malawian pine.

The separation of platinum, palladium and gold from silicate rocks by the anion exchange separation of chloro complexes after a sodium peroxide fusion: an investigation of low recoveries

A series of experiments was undertaken to measure the recovery efficiency of platinum, palladium and gold from silicate rocks using a sodium peroxide fusion followed by anion exchange separation of the analytes as chloro complexes. Results obtained by graphite furnace atomic absorption spectrometric analysis of standard solutions prepared in dilute HCl or HCl-acidified sodium peroxide solution showed that recoveries were near quantitative. However, when standard solutions were added to an alkaline sodium peroxide solution, which was then acidified, low results were obtained for platinum and gold (46% and 76% respectively). Low and variable results were also obtained when standard solutions were added to a peridotite sample that had been dissolved by the state procedure, and in the analysis of the South African Bureau of Standards certified reference material, SARM 7. Various experiments were undertaken to investigate these low recoveries, but the reason proposed here is the formation of hydroxychloro compounds in alkaline solution which are not, on acidification with HCl, converted quantitatively to the chloro complex necessary for quantitative anion exchange separation. It is concluded that a sodium peroxide fusion followed by an anion-exchange separation does not appear to form the basis of a successful technique for the determination of platinum, palladium and gold in silicate rocks.

Staff radiation doses during eight years in a nuclear medicine radiopharmacy

It is important that staff radiation doses be kept 'as low as reasonably achievable' (ALARA). Staff working in the radiopharmacy and nursing staff responsible for injecting radionuclides are being monitored constantly in our department. We report here on the effective doses and doses to the hands received by staff at two hospitals during 8 years from January 1985 to December 1992. In addition to the doses determined monthly by the South African Bureau of Standards' Radiation Protection Service (SABS), radiation doses received to the hands and whole body were measured every week using lithium fluoride thermoluminescent dosimetry (TLD). The workload (number of patient studies each year) and the estimated amount of 99Tcm received per month were also established, and results have been expressed in relation to these where possible. The combined radiation doses and the absorbed dose per unit activity a single radiographer would have received, since 1988 when radiopharmacy duties were centralized, were calculated. The highest total radiation dose received in any one year by any one person at hospital A was 223.53 mSv to the hands, and 10.20 mSv and 8.37 mSv to the whole body depending on the dosimeter used. The corresponding values for hospital B were 54.05 mSv to the hands and 6.94 mSv and 4.43 mSv to the whole body. If only one radiographer should do all the work the calculated highest dose received would be 447.06 mSv to the hands and 9.68 mSv SABS effective dose.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of zircon by laser ablation and solution inductively coupled plasma mass spectrometry

Laser ablation inductively coupled plasma mass spectrometry has been applied to the analysis of five zircon reference materials (RMs): Bureau of Analysed Samples, British Chemical Standard, Certified Reference Material (BAS BCS CRM) 388 Zircon; BAS RM 204a Zircon; British Geological Survey, Institute of Geological Sciences RM 35 Zircon; South African Bureau of Standards, South African Reference Material 13 Zirconium Concentrate; and Standards Association of Australia, Australian Standards Certified Reference Material 008 Zircon Sand Concentrate. Hafnium, Y, REE, Th and U have been determined in each of these samples. Methods of sample preparation and calibration procedures are described for fused glasses, solutions and pressed powders. The results obtained for BAS BCS CRM 388, by solution analysis and laser ablation, with both standard additions and calibration using a spiked synthetic zircon, are compared with an independent analysis using instrumental neutron activation analysis. The analytical results for all of the zircon RMs demonstrate the agreement between the solution data and those obtained from laser ablation of glasses. Provisional results indicate that pressed powders of zircon RMs can be used to calibrate the laser ablation system.

A review of: “Proceedings of the First Annual Conference of the Ergonomics Society of Southern Africa”. (Pretoria: Design Institute of South African Bureau of Standards, 1985).

(1986). A review of: “Proceedings of the First Annual Conference of the Ergonomics Society of Southern Africa”. (Pretoria: Design Institute of South African Bureau of Standards, 1985). Ergonomics: Vol. 29, No. 6, pp. 843-843.

Short-Term Performance of Integral Solar Water Heaters

The 8-hr daily test of solar integral or collector/storage domestic water heaters is considered. For the case of no draw-off, it is shown that a computer simulation gives results closely in agreement with an integral equation which involves the collector parameters, the total insolation and the daily temperation variation, but does not require the actual daily ambient temperature. The relationship of this test to integral unit performance when water is drawn off according to various demand patterns is investigated, and it is shown that the short-term efficiency is typically reduced to two thirds of the daily test result, but can be as low as one third. Thus a simple thermal test such as that specified by the South African Bureau of Standards, and other standards organizations, should at best be regarded as a comparison between various units of similar type, although even there the importance of optical efficiency is overemphasized. Simple tests do not provide a guide to performance in actual service.

Toxicity testing of oil spill dispersants in South Africa

Prior to 1981, manufacturers of oil spill dispersants wishing their products to carry the South African Bureau of Standards (S.A.B.S.) mark of approval or to conform to the applicable S.A.B.S. specification had to have the testing undertaken in the United Kingdom. A new test was introduced in the United Kingdom in 1975, and this and several other tests in use worldwide are reviewed. After consideration of the requirements of a dispersant toxicity test, the necessary modifications for the South African situation are detailed. Results show that the test is comparable with those in use overseas as regards licensing purposes, but there are still basic research problems on dispersant use to be overcome.