This study compared the wood properties of five species as potential wood carving materials with ... more This study compared the wood properties of five species as potential wood carving materials with those of five commonly used species. Five small logs each of potential and conventional wood carving species were randomly selected and cut into billets measuring 1.3m in length. Five smooth clear wood specimens of 20×20×100mm and 20×20×20mm for each of hardness and density determination respectively were obtained for each species and tested following procedures of BS 393: 1957. Wood working characteristics and other parameters desired in wood carving were determined using larger pieces derived from the five logs. Analysis of variance (ANOVA) was used to determine the effect of species on density and hardness. Dalbergia melanoxylon had the highest density and harness while Branchystegia spicioformis had the lowest density and Afzelia quanzensis the lowest hardness. Density and hardness were not significantly different between conventional and potential woodcarving species. Hardness for Terminalia prunoides and Manilkara sansibarica was not significantly different from that of conventional species such as Dalbergia melanoxylon and Bracyhlaena huillensis. A positive correlation between the species hardness and their densities was established (r=0.774). The planing, cutting and finishing characteristics of all the species was dependent on the density. However, some of the potential species had colour that is a contrast to that of conventional species. Since the five potential species do possess most of the characteristics desired in wood carving species and also a number of them have short rotation cycle, they can be considered as alternative raw materials for carving.
The knowledge about the physical characteristics of seeds, whether coated or not, is essential fo... more The knowledge about the physical characteristics of seeds, whether coated or not, is essential for the design of machines and equipment. Therefore, the objective of this work was to determine the physical characteristics of colza (Brassica napus L.) seeds coated with bentonite, gypsum and kaolin, treated with fungicide (carboxin + thiram) and aqueous extract of black pepper (Piper nigrum L.). The untreated colza seeds were submitted to the coating process using bentonite, gypsum and kaolin as fillers, and as treatment products were used as fungicide (carboxin + thiram) and an aqueous extract of black pepper which were added to an aqueous solution of 30% PVA glue (cementing mixture). Then the physical characteristics were determined: diameter, number of times increased, porosity, angle of repose, resistance, classification in sieves and weight of one thousand seeds. The experiment was organized in a completely randomized design and arranged in a factorial scheme. The means, when necessary, were compared by the Scott-Knott test. The colza seeds coated with bentonite presented greater diameter, number of times increased, porosity, angle of repose and weight of a thousand seeds, followed by gypsum and kaolin. The treatment products had little influence on the physical characteristics of the coated seeds.
Studies on the effects of hydrogels on soil amendments, moisture conservation and growth of Cajan... more Studies on the effects of hydrogels on soil amendments, moisture conservation and growth of Cajanus cajan in arid and semi-arid lands were carried out. Seedlings of C. cajan were established both in the nursery and in the field with and without hydrogels. In the field, three replications were used with three levels of hydrogels concentration (7 g, 11 g, and 15 g). Control seedlings were established in soils without hydrogels. In the nursery, root collar diameters and heights were measured every two weeks up to eight weeks. Seedlings established without hydrogels in the nursery were transplanted into field soils with none, 7 g, 11 g and 15 g of hydrogels. Root collar diameters and heights were again measured every month for three months. In addition, soil was collected randomly once every month from the base of each seedling and analyzed for soil moisture using standard laboratory procedures. All data were subjected to analysis of variance. The results show that growth in both the height and root collar diameter of the species was significantly different at the three levels of hydrogels. This suggests that use of hydrogels retards plant growth in nursery soils but improves growth in the field. Hydrogels increased soil moisture volume from 8.3% to 10% in H 15g level of hydrogels under C. cajan after transplanting. It was concluded that hydrogels do not contribute to growth of seedlings in the nursery but they do so after transplanting. Hydrogels increase soil moisture in the soil, so they are recommended for use in semi-arid lands to boost the survival and growth of seedlings.
Effect of Fungal Degradation of Wood Chips on Pulp and Paper Properties at Panafrican Paper Mills, Webuye, Kenya
Losses caused by wood decay fungi in a Pinus patula chip pile in storage were studied for six mon... more Losses caused by wood decay fungi in a Pinus patula chip pile in storage were studied for six months at Panafrican Paper Mills, Webuye, Kenya. The losses were quantified in terms of pulp yield, pulp quality, and paper properties. Light microscopy and scanning electron microscope observations confirmed that soft rot, white rot and brown rot caused fungal decay in the pile. Tests on pulp quality showed that severe fungal attack at 1m height reduced fibre length to less than 2.0 mm compared to 3.8 mm for the control at both 1m and 4m height. Pulp yield loss of up to 12.0% was recorded amounting to about 40 ha of pulpwood going to waste per year. Statistical comparisons using the Duncan's Multiple Range Test indicated that strength values for paper specimens from the degraded chips were significantly lower than that of the control. Paper strength properties decreased substantially within six months with the tensile, tear and burst strengths decreasing by almost 17%, 19.0% and 14.0% ...
SIRMAh P, MbURU F, IAyCh K, DUMARcA y S & GeRARDIN P . 2011. Potential antioxidant compounds from... more SIRMAh P, MbURU F, IAyCh K, DUMARcA y S & GeRARDIN P . 2011. Potential antioxidant compounds from different parts of Prosopis juliflora. Research was carried out to explore antioxidant properties of Prosopis juliflora extractives and their additional utilisation value. Results showed that P. juliflora contained important amounts of flavanols, constituting of 4’-O-methyl-gallocatechin, (+)-catechins and (-)-mesquitol. Their amounts are different and highly dependent on the wood sample location in the tree. Reasons for these differences are not yet fully understood and need further investigation. Heartwood contained (-)-mesquitol as the main secondary metabolite responsible for the strong antioxidant properties of crude extracts obtained with solvents of different polarities. (-)-Mesquitol was also the main component of gums exuding from the stem. Crude bark extractives showed lower antioxidant properties which were attributed to the presence of 4’-O-methyl-gallocatechin. The lower an...
On the reasons of Prunus africana natural durability : [Preprint]
Analysis of Prunus africana heartwood extractives was studied with the aim of understanding the r... more Analysis of Prunus africana heartwood extractives was studied with the aim of understanding the reasons for its high natural durability. Soxhlet extractions of wood powder using different solvents were carried out. Effect of each extracts at different concentrations was evaluated on the growth of several fungi among which Coriolus versicolor, Poria placenta, and Aureobasidium pullulans. Results showed high inhibition rate against all tested fungi. Growth inhibition was particularly important in the case of dichloromethane extracts, which were active even at low concentration. Impregnation of dichloromethane extracts in beech wood inhibited totally wood degradation caused by Coriolus versicolor. Soxhlet extraction of wood blocks was also carried out and the wood blocks tested against termites. Extracted wood blocks showed lower resistance against termites while the unextracted ones were resistant. Evaluation of antitermitic activity on filter paper using the no choice method indicate...
Prunus africana heartwood and sapwood were extracted using different solvents. Extractives were t... more Prunus africana heartwood and sapwood were extracted using different solvents. Extractives were tested against fungi and termites in relation to the natural durability of Prunus africana. These were tested against Coriolus versicolor, Poria placenta, and Aureobasidium pullulans at concentrations. High inhibition was realized and increased with extract concentration. In some instances, fungal growth started after the control Petri dish was fully colonized showing fungistatic effect than fungicidal effect. Extracted and un-extracted wood samples were also tested against termites. When tested against Coriolus versicolor in the laboratory Prunus africana showed high natural durability. Extracted wood showed low resistance against termites while un-extracted was totally resistant. Dichloromethane extract showed the highest inhibition rate compared to water, acetone and toluene/ethanol extracts against fungi and termites. Microscopie analysis indicate the presence of important quantities ...
L'etude a pour objectif d'evaluer la durabilite et les proprietes technologiques d'un... more L'etude a pour objectif d'evaluer la durabilite et les proprietes technologiques d'une espece exogene du Kenya, Prosopis juliflora, introduite au debut des annees 1970 pour augmenter le couvert forestier et lutter contre la desertification. La durabilite du duramen vis-a-vis des champignons, testee dans des conditions de laboratoire, indique que le bois presente une bonne resistance aux agents de pourriture blanche et de pourriture brune. Le bois contient une teneur importante d'extractibles, qui semble presenter un effet limite sur l'inhibition de la croissance des champignons. De plus, le bois est facilement impregnable, permettant d'envisager son utilisation dans des classes d'emploi elevees apres traitement adequat. La resistance aux termites evaluee dans des conditions de laboratoire et de champ indique une faible susceptibilite du bois de P. juliflora, qui semble fortement liee a la presence des substances extractibles. Le bois presente une bonne st...
This study investigated how total land size owned influenced Jatropha curcas adoption in Yatta Di... more This study investigated how total land size owned influenced Jatropha curcas adoption in Yatta District. The study applied quantitative research method where questionnaires were administered to 240 respondents selected through multi-stage sampling technique. Data analysis was carried out using regression analysis and chi square test. It was found that farmers who had adopted Jatropha curcas cultivation were significantly low at 15.4%. It was also found that total land size owned was not a major factor influencing land size allocated to Jatropha cultivation since total land size owned accounted for only 28% variance of land size allocated to Jatropha cultivation and 78% of respondents were not willing to convert their pasture lands to Jatropha farms. An area of 248 acres was under Jatropha cultivation in the district which is equivalent to 0.038% of the total district area coverage. It was concluded that adoption of Jatropha in Yatta District was low. There was a negative correlation between total land size owned and land size allocated to Jatropha cultivation. Total land size owned did not have substantial influence on size of land allocated to Jatropha cultivation as willingness to convert pasture land to Jatropha farms, lack of alternative land for farming, land tenure and control and population density influenced on land size allocated to Jatropha cultivation.
Studies on the effects of hydrogels on soil amendments, moisture conservation and growth of Cajan... more Studies on the effects of hydrogels on soil amendments, moisture conservation and growth of Cajanus cajan in arid and semi-arid lands were carried out. Seedlings of C. cajan were established both in the nursery and in the field with and without hydrogels. In the field, three replications were used with three levels of hydrogels concentration (7 g, 11 g, and 15 g). Control seedlings were established in soils without hydrogels. In the nursery, root collar diameters and heights were measured every two weeks up to eight weeks. Seedlings established without hydrogels in the nursery were transplanted into field soils with none, 7 g, 11 g and 15 g of hydrogels. Root collar diameters and heights were again measured every month for three months. In addition, soil was collected randomly once every month from the base of each seedling and analyzed for soil moisture using standard laboratory procedures. All data were subjected to analysis of variance. The results show that growth in both the height and root collar diameter of the species was significantly different at the three levels of hydrogels. This suggests that use of hydrogels retards plant growth in nursery soils but improves growth in the field. Hydrogels increased soil moisture volume from 8.3% to 10% in H 15g level of hydrogels under C. cajan after transplanting. It was concluded that hydrogels do not contribute to growth of seedlings in the nursery but they do so after transplanting. Hydrogels increase soil moisture in the soil, so they are recommended for use in semi-arid lands to boost the survival and growth of seedlings.
Journal of the Indian Academy of Wood Science, 2013
Studies were carried out on termite and fungal resistance of the lesser known Albizia malacophyll... more Studies were carried out on termite and fungal resistance of the lesser known Albizia malacophylla Kenyan wood species. In addition wood dimensional stability, amount and chemical nature of heartwood extractives was also evaluated. Wood resistance against white rot tropical fungi was based on a laboratory soil bed test and subterranean termite resistance in the field according to American Wood Protection Association: E7-93 (1993) standard. Wood extractives were subjected to infra-red analysis using standard laboratory procedures. Albizia malacophylla heartwood is dimensionally stable (5.5 %) with a less dimensionally stable sapwood (9.6 %). Heartwood extractive content is high (9.7 %) in comparison to sapwood (4.6 %). Albizia malacophylla heartwood is resistant to fungi (8.1 %) mass loss and very resistant to termites (4.8 %) mass loss reported after 6 months exposure. Removal of extractives significantly lowered heartwood dimensional stability, termite and fungus resistance. Heartwood extractives were able to inhibit the growth of fungi under laboratory sterile conditions. Infra-red analysis of crude heartwood extractives indicated presence of aldehydes, ketones carbonyl compounds, esters, aromatic, carboxylic acids and aliphatic carbonyl compounds. Put together, the nature, amount of heartwood extractives and wood dimensional stability are at the origin of the found termite and fungus resistance of A. malacophylla wood.
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