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Chemical composition and machinability of selected species from Mozambique

Lhate, Inacio Arnaldo (2011). Chemical composition and machinability of selected species from Mozambique. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2011:48
ISBN 978-91-576-7592-7
[Doctoral thesis]

[img] PDF (Doctoral dissertation )


The objectives of the current work were to carry out a survey on timber sector in Mozambique and to determine chemical, calorific and machinability features of selected species. Mozambican timber sector was described as dominated by selective harvesting practices on a few hardwood species out of 118 species growing in the forest with potential for industrial timber. Selective logging is believed to be due to the demand in both domestic and international markets of traditionally used, and lack of technical data on lesser used species. In order to avert the negative effect of selective logging, this work argued the need to widen the resource base by studying lesser used species. Taking into account stock volumes recorded in the last forest inventory, the lesser used species, Acacia nigrescens Oliv, Icuria dunensis Wieringa, Pseudolachnostylis maprounaefolia Pax, and Sterculia appendiculata K. Schum were selected to assess their chemical, calorific and machinability features. Lesser used species were compared with traditionally used species, namely, Afzelia quanzensis Welwn, Milletia stuhlmannii Taub, Pericopsis angolensis Meeweven, and Pterocarpus angolensis DC, regarding chemical and calorific features. Aiming to get a thorough chemical characterization along radial direction, samples for chemical analyses were taken from sapwood, outer and inner heartwood. Chemical, proximate and ultimate analyses were performed according to standard methods. The contents of carbohydrates, extractive, ash, volatiles and high heating values were in ranges considered normal for tropical species. Contents of lignin and minerals were unexpectedly high in Pseudolachnostylis, reaching 37.51% and 2.2% (wt%, extractive free) on a dry basis, respectively. Based on the determined chemical features, it was concluded that Acacia and Pseudolachnostylis were similar to well-known, whereas Icuria and Sterculia differed from the known species. In ranking of all studied species using fuelwood value index (FVI), Acacia was best ranked, whereas Sterculia was worst ranked. Acacia, Pericopsis, Pseudolachnostylis and Sterculia, considered as lesser used in the study, were subjected to experiments for cutting forces and tool wearing measurements. Density measurements on samples for cutting forces and tool wearing experiments were performed with the aid of a CT scanner. Two different cutting tools 20˚ and 30˚ rake angle were used. Before cutting, the edge radius of the tools was measured. Main cutting force in 90˚-90˚ and 90˚-0˚ cutting directions were measured by piezoelectric gauge. Tool wearing experiments were performed on a shaper using cemented carbide tools for woodworking and fixed cutting conditions. Edge recession and tool wear radius were measured for monitoring tool wearing. Ranking the species using cutting forces only or tool wearing only for machinability recorded different earnings, and for measuring the net effect of machining output variables, this work suggested the Digraph and Matrix Method as an expeditious and integrated method to evaluate the machinability of lesser used species. Based on the calculated indexes, the easiest species to be machined was Sterculia, whereas the most difficult species to be machined was Acacia. Cutting forces earned by Acacia seemed to have been affected by anatomical features not measured in current work.

Authors/Creators:Lhate, Inacio Arnaldo
Title:Chemical composition and machinability of selected species from Mozambique
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :2011
Number of Pages:56
UNSPECIFIEDI Ali, A., Uetimane Jr, E., Lhate, I., Terziev, N. (2008). Anatomical characteristics, properties and use of traditionally used and lesser known wood species from Mozambique: a literature review. Wood Sci Tecnhol, 42, 453-472.
UNSPECIFIEDII Lhate, I., Cuvilas, C., Terziev, N. & Jirjis, R. (2010). Chemical composition of traditionally and lesser used wood species from Mozambique. Wood Material Science and Engineering, 5, 143-150.
UNSPECIFIEDIII Cuvilas, C., Lhate, I., Jirjis, R., Terziev, N. (2011). Characterization of wood species from Mozambique as fuel. for publication in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects (Accepted)
UNSPECIFIEDIV Cristovão L., Lhate, I., Grönlund, A., Ekevad, M., Sitoe, R. (2011). Tool wear for lesser-known species from Mozambique. Wood Material Science and Enginering, 1-7.
UNSPECIFIEDV Lhate, I., Cristovão, L., Ekevad, M., Sitoe, R. (2010). Cutting forces for lesser used species from Mozambique. Accepted to Wood Machining Seminar to be held in Skellefteå in June, 7-10, 2011.
Place of Publication:Uppsala
Publisher:Department of Forest Products, Swedish University of Agricultural Sciences
ISBN for printed version:978-91-576-7592-7
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:K Forestry > K01 Forestry - General aspects
K Forestry > K50 Processing of forest products
Subjects:Obsolete subject words > TECHNOLOGY
Agrovoc terms:hardwood, wood properties, chemical composition, energy value, mozambique
Keywords:chemical composition, cutting forces, fuelwood, lesser used species, machinability, tropical hardwood species, tool wear
Permanent URL:
ID Code:8207
Department:(S) > Dept. of Forest Products (until 180101)
External funders:Swedish International Development Cooperation Agency
Deposited By: Engineer I A Lhate
Deposited On:27 Jun 2011 12:37
Metadata Last Modified:02 Dec 2014 10:46

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