The Effects of Some Manufacturing Variables on the Properties of Particleboard

The effects of type of wood furnish particle-board, specific gravity and press closing speed on properties of resultant particleboard were investigated. Tests were done in accordance with the provisions of ASTM D 1037 - 78 and property values compared with minimum values set by Commercial Standard - CS 236 - 66. Property values investigated were Modulus OJ Rupture (MOR) andModulus Of Elasticity (M.O.E.) in bending as well as the Internal Bond (IB). Data were analyzed using factorial analysis and regression analysis with Dummy Variables. Most variables and/or their interaction were found to have significantly (at 0.01 level) affected properties. Using compression ratio (ratio of particleboard specific gravity/furnish specific gravity), it was possible to arrive at equations, which gave predicted best estimates of M.O.R; M.O.E. and lB. Similarly, regression equations of compression ratio on M.O.R, M.O.E. and 1B show r = 0.790, r = 0.761 and r = - 0.263 respectively for boards made by fast closing speed while r = 0.601, r = 0.584 and r = -0.450 for slow closing speed, respectively. A student t- test between means of predicted values and experimental results were not significantly different (at 0.05 level) except for all maple board at 0.6 sp. gravity and 3-layer board at 0.7 sp. gravity both of which were made by slow press closing speed. All boards satisfied the provisions set in CS 236 - 66 except boards manufactured from Hard Maple shavings and exposed to the slow press closing speed treatment

Bacteria associated with contamination of ready-to-eat (RTE) cooked rice in Lagos-Nigeria

The bacteria associated with contamination of ready-to-eat (RTE) cooked rice in Lagos, Nigeria were studied using standard microbiological methods. The objective of this study was to investigate the distribution of pathogenic bacteria recovered from RTE cooked rice in Lagos, assess bacteria load in the contaminated RTE cooked rice and evaluate their microbial quality. The microbial load of the RTE cooked rice ranged from 1.5 ± 0.29x 104- 4.8 ± 0.46x 106cfu/g for three markets. A further test revealed that the average bacteria counts at Ketu was significantly different from those at Yaba and Odogunyan. However it was found that counts at Yaba and Odogunyan were not significantly different. Based on the specification by the International Microbiological Standard limits for Foods (IMSF), the levels of contamination of the total samples that were above and below microbiological acceptable limit were 91.7% and 8.3% respectively. The predominant pathogenic bacteria associated with contamination of the RTE cooked rice samples were identified as Staphylococcus aureus, Brahamella sp, Enterobacter aerogenes and Salmonella typhi. Out of a total of 36 RTE cooked rice samples analyzed, Enterobacter aerogenes 36 (100%) had the highest occurrence followed in descending order by Staphylococcus aureus 33 (91.7%), Brahamella sp. 29 (80.6%) and Salmonella sp. 25(69%). The results indicated that most of the RTE cooked rice samples examined in this study did not meet bacteriological quality standards. These findings suggest that the presence of food pathogens in RTE rice hawked in our local markets may pose serious potential health risks to the consumers in the public.© 2015 International Formulae Group. All rights reserved.Keywords: Contamination, pathogenic, bacteria, ready-to-eat (RTE), cooked ric

Physical, mechanical and hydration kinetics of particleboards manufactured with woody biomass (Cupressus lusitanica, Gmelina arborea, Tectona grandis), agricultural resources, and Tetra Pak packages

Lignocellulosic wastes resulting from agricultural activities as well as Tetra Pak residues from urban centres can cause significant levels of pollution. A possible action to minimize this problem is to use them in the production of particleboards. The purpose of this study was to evaluate the physical, mechanical, and hydration properties of particleboards manufactured with the mixture of woody biomass (Cupressus lusitanica, Gmelina arborea, and Tectona grandis) and either agricultural wastes [pineapple leaves (Ananas comosus) and palm residues (Elaeis guineensis)] or Tetra Pak residues (TP). The results show that the particleboards prepared with TP and woody biomass can reduce the swelling and water absorption in up to 40% and 50% compared with particleboards without TP. Also, these particleboards had increased flexure resistance and shear stress (up to 100%) compared with those without TP. On the contrary, particleboards prepared with pineapple leaves in combination with woody biomass showed the lowest mechanical properties, particularly for tensile strength, hardness, glue-line shear, and nail and screw evaluation.Los desechos lignocelulósicos resultantes de las actividades agrícolas, así como los residuos de Tetra Pak de los centros urbanos pueden causar niveles significativos de contaminación. Una posible acción para minimizar este problema es usarlos en la producción de tableros de partículas. El propósito de este estudio fue evaluar las propiedades físicas, mecánicas y de hidratación de tableros de partículas fabricados con la mezcla de biomasa leñosa (Cupressus lusitanica, Gmelina arborea y Tectona grandis) y residuos agrícolas [hojas de piña (Ananas comosus) y residuos de palma (Elaeis guineensis)] o residuos de Tetra Pak (TP). Los resultados muestran que los tableros de partículas preparados con TP y biomasa leñosa pueden reducir la hinchazón y la absorción de agua hasta en un 40% y 50% en comparación con los tableros de partículas sin TP. Además, estos tableros de partículas tenían una mayor resistencia a la flexión y al esfuerzo cortante (hasta 100%) en comparación con aquellos sin TP. Por el contrario, los tableros de partículas preparados con hojas de piña en combinación con biomasa leñosa mostraron las propiedades mecánicas más bajas, particularmente para la resistencia a la tracción, la dureza, el corte de la línea de pegamento y la evaluación de clavos y tornillos.Universidad Nacional, Costa RicaEscuela de Químic