AGRICULTURAL & ENVIRONMENTAL ENGINEERING
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Item Characteristics of classroom chairs and desks in use in senior secondary schools in Ibadan, Oyo State, Nigeria(Scholarlink Research Institute Journals, 2010) Adewole, N. A.; Olorunnisola, A. O.The current status of wooden classroom chairs and desks in use in selected Secondary Schools (SS) in Ibadan was investigated. Fifty-four SS were randomly selected; 12 each from rural and semi-urban, and, 10 from urban areas of Ibadan. Random sampling survey was conducted using structured questionnaire and oral interview and to collect data on chairs and desks types, designs, construction materials and methods, durability and cost factors. Joint features, failure pattern and causes were evaluated via on-the-spot assessments. Simple descriptive statistical tool was used for data analyses. Similar furniture geometry, constructional method and failure mode were noted in rural, semi-urban and urban schools. About 90% of the Schools were using wooden chairs and desks. The two predominant designs were the Single-User (SU), and Multiple-User (MU) types. The production philosophy for both furniture types was one-size-fit all. The SU and MU chairs and desks had a relatively short service life with over 80% of them failing within three months. Poor jointing was responsible for over 69% of the failure. As at December, 2009 a pair of SU and MU chairs and desks cost N2500 and N3500 respectively.Item Strength and sorption properties of cement bonded composites made from calamus deerratus and laccosperma secundiflorum canes(Tertiary Education Trust Funds, Nigeria, 2012-04) Adefisan, O. O.; Olorunnisola, A. O."Two layers rattan cement composites were made from Calamus deerratus and Laccosperma secundiflorum particles using cement: sand:rattan mixing ratios of 1:2:0.2 and 1:3:0.2 and calcium chloride (CaCl2) at two levels 0% and 3% (by weight of cement) and subjected to static bending and sorption tests after production. Results showed that rattan-cement mixes had low moduli of rupture, thickness swelling and water absorption rates but high moduli of elasticity and are suitable for low stress out-door applications. While the Calamus composites generally had low strength and high sorption properties than the Laccosperma cement mixes, peeling significantly reduced the strength properties of the Calamus cement composites possibly due to higher presence of cement inhibitors. Addition of CaCl2 significantly enhanced both the strength and sorption properties of composites made from Calamus and Laccosperma particles "Item Effects of selected pre-treatment methods on the hydration behaviour of rattan-cement mixtures(KFRI, 2010) Adefisan, O. O.; Olorunnisola, A. O."The influence of clacium chloride (CaCl2), magnesium chloride (MgCl2), hot-and cold-water pre-treatments, and prolonged storage on the hydration behaviour of particles extracted from Calamus deerratus and Laccosperma secundiflorum rattan canes mixed with cement was investigated. While the untreated rattans inhibited cement setting, pre-treatments generally improved compatibility.The addition of chemical additives and aquenous pre-treatments enhanced the compatibility of the rattan-cement composites while peeling of silicified epidermis generally reduced the compatibility parameters. Pre-storage positively influenced the hydration behaviour of the L.secundiflorum composites while it negatively affected the Calamus composites. Statistical analyses revealed that all the pre-treatment methods employed significantly improved the hydration behaviour of the rattan-cement mixes except water and CaCl2 treatments. The compatibility indices based on the maximum hydration temperature (Tmax),compatibility factor (CA), setting time (tmax) and time ratio indices (tR) did not consistently predict the hydration behaviour of the rattan composites. A modified time ratio index based on the threshold temperature (40oC) is proposed for prediction of the hydration behaviour of rattan-cement mixes "Item Factors influencing prospectives uses of ratten canes as furnish for cement composite production(Forestry Association of Nigeria, 2011) Adefisan, O. O.; Olorunnisola, A. O.This paper discusses the prospective uses of three readily available ratten canes in southern and western Nigeria namely: Laccosperma secundiflorum, Eremospatha macrocarpa, and Calamus deerratus as furnish for Cement Bonded Composites(CBCs) production. Advantages of utilising ratten canes as furnish for CBC production, limiting factors influencing the development of ratten composites and means of curtailment are examined. Ratten canes are potential furniture for CBC production but will require pre-treatment before use to ensure formation of strong crystalline bond.Item Effects of chemical additives on the hydration behaviour of cement composites from calamus and laccosperma canes(2011) Adefisan, O. O.; Olorunnisola, A. O."The effects of calcium chloride (CaCl2) and Magnesium Chloride(MgCl2) on the maximum hydration temperature (Tmax) setting time(tmax) and Time ratio (tR) of Calamus deerratus and Laccosperma secundiflorum particles mixed with Portland cement was investigated. Particles of ratten canes were mixed with cement, water and chemical additives. Hydration tests were performed in thermally sealed thermos flasks while hydration parameters:Tmax and tmax were measured after 24 hrs. The tmax, Tmax and tg ranged between 25.7 to 26.5 hrs,43.1 to 46.6o C and 3.6 to 3.7 respectively without pre-treatment and were between 7.4 to 23.1 hrs,49.3 to 65.7 oC and 1.0 to 3.0 respectively when pre-treated with chemical additives. Findings showed that untreated ratten generally inhibited cement setting probably due to inherent sugar content. Particles of laccosperma canes inhibited cement setting more than those of the Calamus canes. The addition of both CaCl2 and MgCl2 significantly improved the Tmax but reduced the tmax and tr of the ratten-cement mixes. Addition of CaCl2 enhanced the hydration behaviour of the ratten composites more than MgCl2. "