Thesis (MScFor)--University of Stellenbosch, 2007. / ENGLISH ABSTRACT: Unextracted (control) and PHWe Eucalyptus grandis wood chips were pulped at 15% active
alkali (AA) and 1% antraquinone (AQ). Another batch of wood chips were then inoculated
with fungal co-cultures of Aspergillus flavipes and Pycnoporus sanguineus. FCCi wood chips
were incubated for four weeks; one PHWe inoculated experimental treatment was incubated
for three weeks. The full pulping cycle (160 min) was used to digest the experimental
treatments with the exception of one lot of PHWe wood chips that were pulped for 150
minutes. A further experimental treatment of PHWe wood chips was cooked at a reduced AA
charge of 14% and 1% AQ. Analysis of variance (ANOVA) of the data from all the
experimental treatments was conducted and the differences within the experimental treatments
were determined using Statistica (v7, 1984–2006). The F-value (Fischer distribution) and the
p-value as well as a non-parametric test known as the Mann-Whitney procedure was tested at
the 95% confidence limit. For a further enhancement of the 95% confidence limit the screened
yield data was tested by the Bootstrap method. Scanning electron micrographs clearly
demonstrated the changed structure and appearance of the chip cross-sectional area after the
different pretreatments.
Although the mean average results of all the screened pulp yields showed no significant
statistical difference (p> 0.05), differences in screened yield of up to 2.5% were obtained. All
the weighted means of the rejects showed a significant difference (p < 0.05). Other pulp
properties like shive content, chemical consumption, Kappa number, handsheet brightness and
strength tests showed mixed results i.e. rejected or accepted the hypothesis (p> or =or < 0.05).
The hypothesis that the combined PHWE and FCCI of wood chips would further increase the
pulp yield had to be rejected. It is however anticipated that the combination of PHWE with
successive co-culture fungal pretreatment would be very beneficial in obtaining higher pulp
yields for fully bleached chemical pulp. Further research would be required to test this
assumption. This investigation confirmed the expected beneficial effects of combined PHWE
and FCCI pretreatments of wood chips on the strength properties. In addition the combined
treatment also improved the initial bonding strength potential of the unbeaten fibres. / AFRIKAANSE OPSOMMING: Onbehandelde en met onder druk, warm water uitgeloogde Eucalyptus grandis houtspaanders
is respektiefwelik met 15% aktiewe alkali (AA) en 1% antrakinoon (AQ) verpulp. Hierdie is
dan met swamkokulture van Aspergillus flavipes en Pycnoporus sanguineus inokuleer en
respektiewelik vir drie en vier weke inkubeer. Onder druk uitgeloogde houtspaanders is ook
vir 150 minute verpulp by 15% AA 1% AQ en by ‘n verminderde AA van 14%.
Pulpevaluasies is uitgevoer op alle eksperimentele behandelinge. Alle onder druk uitgeloogde
en met swamkokultuur inokuleerde houtspaanders het ‘n laer pulpopbrengs, uitskot,
skilferinhoud, Kappanommer en ‘n hoër RAA en helderheid opgelewer in vergelyking met die
vars houtspaanders. Die vars en warm water uitgeloogde houtspaanders het soortgelyke
pulpopbrengs opgelewer.
‘n Variansieanalise (ANOVA) van die data van alle eskperimentele behandelings is uitgevoer
gebruikmakende van Statistica (V7, 1984 – 2006). Die F-waarde (Fischer-verspreiding) an die
p-waarde so wel as ‘n parametriese toets (Mann-Whitney prosedure) is getoets by ‘n 95%
betroubaarheidsgrens. Vir ‘n verdere verhoging van die 95% betroubaarheidsgrens van die
pulpopbrengs, is die beskikbare data weer getoets met die Bootstrap-metode.
Alle gemiddelde pulpopbrengswaardes het geen beduidende statistiese verkil opgelewer nie
(p>0.05), alhoewel verskille van tot 2.5% in pulpopbrengs verkry is. Alle gemiddelde
uitskotwaardes het ‘n beduidende verskil getoon (p<0.05). Die ander pulpeienskappe soos
skilferinhoud, verbruik aan chemikalieë, Kappagetal, handvel helderheid en sterktewaardes
het gemengde resultate opgelewer maw verwerping of aanvaarding van die hipotese p> or =or
< 0.05. Die hipotese dat die gekombineerde PHWE en FCCI van die houtspaanders die
pulpopbrengs verder sou verhoog moes verwerp word. Daar word egter verwag dat die
kombinasie van PHWE met opeenvolgende swamkokultuur behandeling baie voordelig sou
wees op die pulpopbrengs van ‘n ten volle gebleikte chemiese pulp. Verdere navorsing is
nodig om hierdie veronderstelling te toets. Die ondersoek het die verwagte woordelige effek
van die gekombineerde PHWE en FCCI voorbehandelings van die houtspaanders op die
papierstrkte-eienskappe bevestig. Bo en behalve dit, het die gekombineerde behandeling ook
die aavanklikte bindsterkte potensiaal van die ongeklopte vessels verbeter.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/21655 |
| Date | 12 1900 |
| Creators | Dyantyi, S. D. (Simphiwe David) |
| Contributors | Gerischer, G.R.F., Botha, A., Stellenbosch University. Faculty of Agrisciences. Dept. of Forest and Wood Science. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
| Format | xvii, 122 leaves : ill. |
| Rights | Stellenbosch University |
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