Trial Production and Testing of Cement-Bonded Particleboard from Rattan Furniture Waste

An investigation was conducted on the use of rattan (cane) furniture waste as furnish material for the manufacture of cement-bonded particleboard (CBP). Laboratory scale CBPs were fabricated from hot water pretreated chopped strands of mixed rattan waste obtained from rattan furniture workers in Ibadan, Oyo State, Nigeria. Three-layered boards of 6-mm thickness were made comprising coarse core and fine surfaces at two density levels of 1,050 kg/m3 and 1,200 kg/m3 three CaCl2 concentration levels of: 2.5%, 3.0%, and 3.5%, and using Portland cement-cane mixing ratios of 2.5:1.0, 2.75:1.0, 3.0:1.0, and 3.25:1.0. After board manufacture, ASTM D 1037 (1998) test procedures were employed to obtain strength and moisture absorption properties. Average properties for bending modulus of rupture (MOR) and modulus of elasticity (MOE) of the boards ranged between 0.5 and 1.6 N/mm2, and 480 and 3,563 N/mm2, respectively. Mean thickness swelling (TS) and water absorption (WA) values ranged between 1.1 and 8.6%, and 31 and 51%, respectively. Analysis of variance showed that except for MOE, the levels at which the density, CaCl2 concentration, and cement-cane mixing ratio were used and their interaction had no significant effects on properties of the board. The relatively low strength and water resistance properties of the boards make them suitable only for use in low-stressed interior applications. Further investigations are, however, required on the effects of different cane preparation procedures and other fabrication variables on board properties. This is necessary to provide the guidelines required to adequately control the fabrication process and optimize material properties

ASSESSMENT OF PHYSICAL AND CHEMICAL PARAMETERS OF MODAL SOIL IN RELATION TO POND CONSTRUCTION AND PRODUCTIVITY IN NIGERIA

A study was carried out for five weeks to examine physical and chemical parameters of modal soil in selected areas in relation to pond setting and productivity in Lagos State, Nigeria. Physical (water temperature, soil permeability, bulk density and textural) and chemical parameters (pH, nitrogen and phosphorus) were determined according to standard. Results showed that the soil of the study area belongs to four different textural classes: sandy, sandy clay, clay loam and sandy clay loam. The sandy clay was dominant with 38 % proportion, sandy (28 %), sandy loam (28 %) and sandy clay loam was least with 6 % proportion of the prevalent soil textural class in the study area. Soil permeability (6.2 – 24.9 mm/hr) exceeded the permissible value 4mm/hr, Soil bulk density and pH (1.20 – 1.57g/cm3) and (5.3 – 7.3) were within acceptable limits of 1,4g/cm3 and 7.5 respectively. Nitrogen (20.20 – 29.30 ppm) and phosphorus (1.93 – 6.57 ppm) contents for different soil locations were less than the recommended values of 50.0 and 9.0ppm respectively. These results revealed that the soil locations were not suitable for pond construction and productivity. Pond to be built in these areas requires special techniques such as building of clay core, puddle and compaction and application of lime and fertilizer

OPTIMIZATION OF CHAR IN THE PYROLYSIS OF PALM KERNEL SHELL USING RESPONSE SURFACE METHODOLOGY

Palm oil production yields a considerable quantity of palm kernel shell (PKS). This is locally burnt as fuel for domestic cooking as well as in blacksmith and goldsmith operations. Medium-grade fuel such as char can be derived from PKS through pyrolysis. The optimization of the char yield was investigated using a central composite design of the response surface methodology in a batch reactor. A three -factor three-level design comprising the reaction temperature and provenance were taken as quantitative variables, while varieties a qualitative variable and yield was taken as the response. This study optimized char yield from palm kernel shell (PKS)through pyrolysis. Increasing reaction temperature generally decreased char yields. Variety type, reaction temperature, and provenance all significantly (p < 0.05) affected char yields for both Dura and Tenera varieties studied. The char yield obtained from Tenera variety was greater than Dura variety.  The optimized temperature for both Tenera and Dura varieties was 400oC with yield of 46.85 and 42.68 % respectively, while Odeda provenance representing derived savannah provenance was the best location producing the optimal yield

a-Amylase inhibition, anti-glycation property and characterization of the binding interaction of citric acid with a-amylase using multiple spectroscopic, kinetics and molecular docking approaches

The quest to suppress complications associated with diabetes mellitus is ever increasing, while food additives and preservatives are currently being considered to play additional roles besides their uses in food enhancement and preservation. In the present study, the protective prowess of a common food preservative (citric acid, CA) against advanced glycation end-products (AGEs) formation and its binding interaction mechanism with a-amylase (AMY), an enzyme linked with hyperglycemia management, were examined. Enzyme inhibition kinetics, intrinsic fluorescence, synchronous and 3D fluorescence spectroscopies, ultraviolet–visible (UV–Vis) absorption spectroscopy, Fourier transform-infrared (FT-IR) spectroscopy, thermodynamics, and molecular docking analyses were employed. Results obtained showed that citric acid decreased a-amylase activity via mixed inhibition (IC50 = 5.01 ± 0.87 mM, Kic = 2.42 mM, Kiu = 160.34 mM) and suppressed AGEs formation (IC50 = 0.795 ± 0.001 mM). The intrinsic fluorescence of free a-amylase was quenched via static mechanism with high bimolecular quenching constant (Kq) and binding constant (Ka) values. Analysis of thermodynamic properties revealed that AMY-CA complex was spontaneously formed (DG DH), with involvement of electrostatic forces. UV–Vis, FT-IR and 3D fluorescence spectroscopies affirmed alterations in aamylase native conformation due to CA binding interaction. CA interacted with His-101, Asp-197, His- 299, and Glu-233 within AMY active site. Our findings indicated that CA could impair formation of AGEs and interact with a-amylase to slow down starch hydrolysis; vital properties in management of type 2 diabetes complications

Professional development in teaching and learning for early career academic geographers: Contexts, practices and tensions

This is an Accepted Manuscript of an article published by Taylor & Francis in Journal of Geography in Higher Education on 16th May 2011, available online: doi: 10.1080/03098265.2011.563380This paper provides a review of the practices and tensions informing approaches to professional development for early career academic geographers who are teaching in higher education. We offer examples from Britain, Canada, Nigeria and the USA. The tensions include: institutional and departmental cultures; models that offer generic and discipline-specific approaches; the credibility of alternative settings for professional development in teaching and learning; the valuing of professional development and of teaching in academic systems of reward and recognition; and the challenges of balancing professional and personal life. We summarize concepts of good practice and suggest opportunities for future research

Strength and water absorption characteristics of cement-bonded particleboard produced from coconut husk

Wood-Cement composites were produced from coconut (Cocos nucifera) husk, an agricultural residue with minimal economic utilization in Nigeria. Contrary to conventional practice, the boards were fabricated in the laboratory without external pressure application. The effects of calcium chloride (CaCl2) addition on the hardening time, appearance, bending and compressive strength, and water absorption properties of the boards were also investigated. The boards had a relatively low density with values ranging from about 594 to 650 Kg/m3. The addition of CaCl2 reduced the hardening time of the board by about 50% (from 36 to 12 hours) and also imparted glossiness in the treated boards. The Modulus of Elasticity (MOE) and Modulus of Rupture (MOR) of the untreated boards (677 N/mm2 and 1.25 N/mm2 respectively) were slightly lower than those of the treated boards (1104 N/mm2 and 1.48 N/mm2 respectively). The mean compressive strength of the CaCl2–treated boards (3.68 N/mm2) was also slightly higher than that of the untreated boards (3.39 N/mm2). However, the observed differences were not significant. The rate of water absorption (< 25% after 24 hours) and the resultant thickness swelling

The Past, Present and Future Outlook of the Wood Industry in Nigeria

Nigeria’s vegetational diversity ranging from mangrove swamp along the southern coast through freshwater swamp, lowland rainforest and savanna, progressively into the interior of the country makes possible the growth of over 560 indigenous species of tropical hardwoods, many of which grow to merchantable dimensions. Hence, wood processing for domestic consumption and exportation played a vital role in the Nigerian economy from the late 1700s up till early 1970s, with the 1960s often referred to as the golden age of Nigerian forestry. However, due to forest resources mismanagement, infrastructural deficiencies, economic recession and other factors, the industry fell on hard times beginning from the mid-1970s. While primary wood processing establishments including timber logging, sawmilling and charcoal making managed to survive, virtually all the secondary wood processing factories, excluding those involved in furniture production, became defunct by the year 2000. Although a set of newer medium-sized plywood and match production factories have emerged in recent years, massive importation of secondary wood products has become inevitable in the face of rapid population growth, urbanization, deforestation and desertification. This chapter discusses the past, the present and the future of the wood industry in Nigeria

Development of passive evaporative cooling systems for tomatoes Part II: performance evaluation

Six evaporative coolers were developed for tomatoes using Laterite-Sawdust (LS), Cement-Sawdust (CS), Cement-Eggshell Ash-Sawdust (CES), Laterite (LL), Metal-Laterite (ML) and Concrete (CR) as construction materials. The cooling efficiencies of the units were evaluated with and without being loaded with tomatoes. The result of a 7-day zero loading test showed that the cooling efficiencies of the coolers were in the order of 98.0, 92.3, 81.4, 78.0, 76.6 and 61.2% for LS, LL, CS, ML, CES and CR respectively. The 30-day loading test showed that the coolers were able to extend the shelf life of tomato beyond the 14 days recorded for ambient storage at average temperature and relative humidity of 32oC and 42.3% respectively. Shelf lives of 26, 30,20,20,26 and 23 days were recorded for LL, LS, ML, CR, CS and CES coolers respectively at average temperatures of 24.4,24.1, 25.1, 27.7, 25.2 and 25.6oC and corresponding RH of 93.7, 95, 93, 88.3, 92.8 and 91.8% respectively. The laterite- sawdust cooler provided the best, while the concrete cooler provided the least acceptable cooling conditions.Keywords: Agro-forestry residues, tomato storage, composite materials, evaporative coole

Strength and sorption properties of cement-bonded composites produced from eucalyptus (Eucalyptus tereticornis SM.) veneer waste

This study investigated the effects of wood-cement ratio, calcium chloride (&lt;i&gt;CaCl&lt;/i&gt;&lt;sub&gt;2&lt;/sub&gt;) addition (0-3%) and cold water extraction on strength and sorption properties of cementbonded composites produced from eucalyptus (Eucalyptus tereticornis Sm.) veneer waste. Hammer-milled particles were characterized and used. Boards measuring 150 x 150 mm were manufactured in a low pressure system at wood/cement ratios by weight of 10:90, 20:80 and 30:70 respectively at a target density of 1000kg/m3. Physical, mechanical and sorption properties of the boards were evaluated. About 50% of the eucalyptus particles were retained on 0.85 to 2.36 mm sieve sizes. The loose bulk density ranged between 118 and 136 kg/m3 at a moisture content of 8.8 %. Water absorption by the particles at 24 hours ranged between 286.0% and 433.0%. Modulus of rupture (0.4 - 3.6 MPa), flexural toughness (0.02 - 0.15 KJ/m2), and tensile strength (0.4 - 1.2 MPa) of the boards fell within acceptable limits. In virtually all specimens, over 80% of the water absorption by immersion occurred in the first 1 hour of soaking, a reflection on the water absorption capability of the eucalyptus wood particles. Strength properties not directly measured experimentally and 24-h water absorption values were successfully predicted with existing model equations. Addition of calcium chloride significantly improved the physical and mechanical properties of the panels, while cold water extraction improved dimensional stability. Boards produced with less than 30% wood content exhibited superior strength and dimensional stability properties that can be exploited in ceiling applications where sound absorption is important.Keywords: Eucalyptus, Veneer waste, Cement composite, Strength, dimensional stabilityJournal of Applied Science, Engineering and Technology Volume9,: 42-4