Your search resulted in 24 documents.
The biostatic effect of copper on decay of fire retardant-treated mining timber
1991 - IRG/WP 1507
Blocks of Eucalyptus grandis were treated with 20kg/m³ ammonium sulphate as fire retardant and challenged with Coriolus versicolor. Replicates were soil buried. A second set of blocks was treated with retardant and copper at 6.6 kg/m³ (ie 1% w/w), and challenged similarly. After 8 weeks weight losses produced by Coriolus versicolor in untreated, retardant treated and copper supplemented blocks w...
G D Shelver, E A Shelver, A A W Baecker
A summary of current information on actinomycetes and wood
1978 - IRG/WP 177
B King, R A Eaton, A A W Baecker
A technique for the quantitative isolation of Actinomycetes from decayed wood
1980 - IRG/WP 1116
A technique combining comminution and high-speed homogenisation has been developed for the preparation of suspensions of micro-organisms in colonised wood. When standard inocula of Streptomyces spores were applied to wood, constant proportions of the inocula were recovered. This method was used in conjunction with selective culture media to isolate actinomycetes from wood which had been buried in ...
A A W Baecker, B King
Effects of the anaerobic wood decay bacterium Clostridium xylanolyticum on unbleached Pinus and Eucalyptus pulp
1991 - IRG/WP 1506
Clostridium xylanolyticum has been shown to produce extracellular enzymes capable of degrading wood. The present work was conducted to quantify growth on various lignocellulosic substrates and degradation of pulped wood fibre. In the latter tests Clostridium xylanolyticum was incubated at 35°C under anaerobic conditions in a medium containing 0.2% (w/v) peptone and 4% (w/v) unbleached Pinus and E...
G D Shelver, U Matai, W Van Wyk, A A W Baecker
Transmission poles with sub-standard retentions protected by Field Liners outperform standard poles in service
1997 - IRG/WP 97-40095
Eucalyptus cloeziana 12m transmission poles were treated with sub-standard creosote retentions of 80kg/m3 and Field Liners were fitted to the poles before they were placed in service at Umbumbulu, Kwazulu Natal. Poles treated with standard creosote retentions of 130kg/m3 but without Field Liners were also placed in service in the same area. Core samples were taken from both groups of poles after 1...
M R Behr, G D Shelver, A A W Baecker
Leaching of CCA from Pinus patula during marine trials in the southern hemisphere
1991 - IRG/WP 4167
Pinus patula stakes were treated with CCA to retentions of 31 kg/m³ salts, and were sited in the sea of Port Alfred, South Africa, for two years. Samples were then removed to the laboratory and analysed as before for copper and arsenic. Prelimiary data showing CAA losses from these stakes in the marine environment showed that CCA was longitudinally leached from them, and was also transversly redi...
G D Shelver, C D McQuaid, A W W Baecker
Relative performances of DNBP and CCA wood preservatives in accelerated decay tests
1988 - IRG/WP 3496
The effectiveness of 2-sec-butyl-4,6-dinitrophenol (DNBP) was compared with that of CCA. Test blocks of Pinus patula and Eucalyptus grandis were impregnated to precisely known retentions of approximately 3, 6, and 10 kg/m³ CCA and solvent-borne DNBP respectively. They were then challenged in decay tests comprising soil burial and exposure to monocultures of Chaetomium globosum, Coriolus versicolo...
W H Schnippenkoetter, L D Abraham, A A W Baecker
A new method for the study of microbiological decay of wood in a strictly anaerobic environment
1988 - IRG/WP 2319
Recent work has suggested that strictly anaerobic bacteria may play a role in the biodeterioration of wood, particularly in aqueous environments. However, no suitable test methods exist for the investigation of this hypothesis. An aqueous minimal medium in specifically adapted conical flasks was sterilised, gassed using a 5.5% H2; 31.8% C02; 62.7% N2 gas mixture to remove oxygen and transferred to...
G M Rogers, A A W Baecker
Accelerated decay tests to investigate postulated effects of tannins on CCA efficacy in wood
1988 - IRG/WP 3497
Five groups of blocks (10 x 10 x 5 mm³) viz., Pinus patula, Pinus patula impregnated to 4% (w/w) tannin; Eucalyptus grandis, Eucalyptus grandis with natural tannins extracted; and extracted Eucalyptus grandis with tannins returned as above; were prepared. Blocks from each group were then treated to 0, 5, 10 and 15 kg/m³ CCA and challenged in four 15-week decay tests, viz., soil burial, and expos...
U L Scherer, A A W Baecker
Immunolocalization of xylanase produced by Clostridium xylanolyticum Rogers and Baecker during anaerobic decay of Pinus patula
1991 - IRG/WP 1505
The xylanolytic fraction from a 72h culture of Clostridium xylanolyticum ROGERS and BAECKER was separated using non-denaturing PAGE and then used to raise polyvalent antisera in rabbits. Antibodies were purified using an affinity gel column and coniugated with colloidal gold. Pinus patula was exposed to axenic cultures of Clostridium xylanolyticum for 3 weeks, fixed, embedded and converted to ultr...
A A W Baecker, G M Rogers
Accelerated decay tests on DNBP-treated Pinus patula and Eucalyptus grandis
1987 - IRG/WP 3441
Blocks (10 x 10 x 5 mm³) of Pinus patula and Eucalyptus grandis were impregnated to 0, 1.5, 3.0 and 4.5 kg/m³ 2-sec-butyl, 4, 6 dinitrophenol (DNBP). They were monitored microscopically and for weight losses over 16 weeks against monocultures of Coriolus versicolor and Coniophora puteana. Treated ministakes (10 x 10 x 100 mm³) and blocks in soil contact were similarly monitored to determine wei...
L D Abraham, A A W Baecker
Biostatic film as a primary treatment against pole failure in soil
1995 - IRG/WP 95-40053
Field liners of low density polyethylene (LDPE) film applied as primary treatment of soil-contact surfaces of creosote-treated poles prevented their detoxification and premature failure by establishing hurdles against microbiological colonisation. These hurdles include low water activity, low oxygen tension and nutrient limitations. Moreover, under conditions of high soil moisture, field trials sh...
A A W Baecker, M Behr
The use of propionic acid to prevent Pinus patula biodeterioration during outside chip storage in Zululand
1989 - IRG/WP 3531
Pinus patula SCHIEDE ET DEPPE IN SCHLD. ET CHAM. is susceptible to biodeterioration during outside chip storage (OCS), reducing pulp quality and tear and burst indices of resulting paper. Accelerated laboratory trials showed that chips treated with 2% (w/v) propionic acid and stored for 17 weeks, produced pulp of quality indistinguishable from fresh untreated chips. Pulp tests during field trials ...
S Ismail, E J Smith, A A W Baecker
Quantification of wood decay effects by HPLC analysis
1992 - IRG/WP 92-1576
The present work quantified the effects of the white rot basidiomycetes Coriolus versicolor and Phanaerochaete chrysosporium, and also those of the brown rot fungi Coniophora puteana and Lentinus lepideus, on Pinus patula and Eucalyptus grandis. Wood colonisation was quantified by Kjeldahl nitrogen determinations converted to biomass assays, and degradation was quantified by weight losses produced...
V Singh, M Tarin, G D Shelver, A A W Baecker
The colonisation pattern of anaerobic fungi in wood
1989 - IRG/WP 1403
Timber foundations may be degraded in service in anaerobic conditions. The present work was conducted to investigate whether anaerobic fungi could colonise wood, using rumen fungi as test microorganisms. Strictly anaerobic fungi were isolated and purified from cow dung and goat and sheep rumen fluids respectively. Colonisation of Eucalyptus grandis and Pinus patula by these fungi and Neocallimasti...
A H Wiederhold, M Morrison, A A W Baecker
Field Liners™ prevent creosote migration from transmission poles to soil during service
1996 - IRG/WP 96-40067
A full scale trial utilised 150 12m Eucalyptus grandis transmission poles treated with standard retentions of creosote according to SABS Method 457. One hundred poles had Field Liners™ applied while 50 did not. The 150 poles were used to complete an electricity transmission line in Southern KwaZulu-Natal. After 18 months service, incremental cores were taken from 15 cm below the ground lines of ...
M R Behr, G D Shelver, A A W Baecker
Surface accumulation of copper on CCA-impregnated Pinus patula stakes during marine preservative trials in the southern hemisphere
1992 - IRG/WP 92-4181
Pinus patula stakes treated with CCA to target retentions of 30 kg/m³ salts were exposed to sea water in marine and estuarine ecosystems off the coast of Southern Africa for two years. Samples were then analysed for copper and arsenic. Analysis of samples from the marine ecosystem showed (IRG/WP/4167) that arsenic was longitudinally and transversely leached from the wood, whereas the copper was r...
G D Shelver, C D McQuaid, M Tarin, A A W Baecker
A non-pressure method of protection based on hurdle theory to control the spectrum of internal environmental factors which affect the decay of poles in soil contact
1993 - IRG/WP 93-20005
A field trial was conducted to establish whether superficial barrier linings on poles in soil contact could function as environmental hurdles against the growth of biological agents and thus provide preventative methodology to preclude premature failure of vineyard poles under flood-irrigation. Assessment after 52 weeks exposure to the prevailing conditions and sub-tropical environment showed that...
A A W Baecker
Detection of methanogenic bacteria in mining timber
1988 - IRG/WP 1352
Methane explosions in gold mines have been attributed to spontaneous ignition of methane/air mixtures. Biogenesis of methane in the heartwood of diseased trees has been shown, but never in timber in service. Studies were therefore undertaken to establish whether methanogens were present in wooden pit props. Core samples were removed by Pressler increment borer from props in disused areas 2,600 m d...
L D Abraham, K Westlake, R I Mackie, J F Putterill, A A W Baecker.
Anti-bluestain treatment developed for log cargoes stacked in subtropical conditions for export on logging ships
1995 - IRG/WP 95-30081
Subtropical environments impose conditions of temperature, humidity and rainfall which are optimal for growth of bluestain fungi. Unprotected softwoods under such conditions become bluestained three days after felling. Furthermore, intervals between harvesting and delivery to export marketplaces exceed the 30-day protection periods attributed to anti-bluestain formulations in such conditions. Thes...
A A W Baecker, M Behr, G D Shelver
Three-year field trials of polymeric formulations which provide a new basis for the invention and design of non-toxic wide-spectrum wood preservatives
1994 - IRG/WP 94-40029
Three types of non-toxic polymeric formulations invented using a new approach to wood preservation were challenged with termites and fungi in three-year ground-contact field trials in the sub-tropical climate of Natal. These formulations were copper soaps of carboxylic acid groups of unsaturated fatty acids of waxes and edible vegetable oils; of resin acids of rosin, and, of synthetic unsaturated ...
A A W Baecker, A Pizzi
Quantification of creosote migration down wooden poles and the prevention of its depletion during flood irrigation
1994 - IRG/WP 94-50032
Polyethylene field liners heat-shrunk onto soil-contact surfaces prevented decay of creosote-treated Eucalyptus grandis vineyard poles under flood-irrigation. The present work quantified losses of creosote from these poles after six and 24 months' service. After six months' service the mean creosote retention of unlined poles above the ground line was 12.62% (m/m dry wood), with ...
M Behr, A A W Baecker
A study of methanogenesis and sulphate-reduction: A possible source of explosive gas mixtures in a gold mine
1989 - IRG/WP 1399
Previous work isolated anaerobic bacteria from timbers and drainage water in a gold mine. The present work identifies the predominant methanogen in the mine ecosystem as Methanobacterium bryantii and sulphate-reducing isolates as Desulphovibrio desulphuricans and Desulphotomaculum antarcticum. Laboratory studies using model systems evaluate the activity of methanogenic and sulphate-reducing bacter...
L D Abraham, J F Putterill, A A W Baecker
Environmental protection and long term in-service sustainability of preserved wooden poles is secured by non-toxic barrier protection system – History and case studies in South Africa
2018 - IRG/WP 18-50340
Non-toxic flexible sheeting systems have been developed to encapsulate the ground contact regions of preserved wooden poles and prevent their premature failure in South Africa since 1992 but the technology also has a long history of resistance by individuals with vested interests in the built-in redundancies of such poles. The concept has, however, been simultaneously validated by many independent...
A A W Baecker