Abstract: In this study, solid phase micro-extraction (SPME)
was optimized to improve the sensitivity and accuracy in
formaldehyde determination for plywood panels. Further work has
been carried out to compare the newly developed technique with
existing method which reacts formaldehyde collected in desiccators
with acetyl acetone reagent (DC-AA). In SPME, formaldehyde was
first derivatized with O-(2,3,4,5,6 pentafluorobenzyl)-hydroxylamine
hydrochloride (PFBHA) and analysis was then performed by gas
chromatography in combination with mass spectrometry (GC-MS).
SPME data subjected to various wood species gave satisfactory
results, with relative standard deviations (RSDs) obtained in the
range of 3.1-10.3%. It was also well correlated with DC values,
giving a correlation coefficient, RSQ, of 0.959. The quantitative
analysis of formaldehyde by SPME was an alternative in wood
industry with great potential
Abstract: The efficiency of chitosan beads processed from 4
marine animal shells; white leg shrimp (Litopenaeus vannamei), mud
crab (Scylla sp.), horseshoe crab (Carcinoscorpius rotundicauda),
and cuttlefish bone (Sepia sp.), for the adsorption experiments of
ammonia and formaldehyde were investigated. The porosities of
chitosan from the shells looked like beads were distinctly examined
under SEM. The original pores of those shells on the surface areas
compose of evenly fine pores. The shell beads of cuttlefish bone and
horseshoe crab show the larger probably even porosity, while on
those white leg shrimp and mud crab contain various large and fine
pores. The best adsorption at pH 9 in 18 mg/l ammonia at 2 hours
yield on cuttlefish bone, horseshoe crab, mud crab and white leg
shrimp with the average percent of 59.12, 51.45, 45.66 and 43.52,
respectively. Within 30 minutes the formaldehyde absorbers (at pH 5
in 8 μg/ml) revealed 46.27, 26.56, and 18.04 percent capacities in
cuttlefish bone, mud crab and white leg shrimp beads; while 22.44
percent in the horseshoe crab at pH 7. The adsorption capacities and
the amounts of beads showed a positive correlation. The adsorption
capacity relationship between pH and the gas concentrations were
affected by these qualities of chitosan beads.
Abstract: A new generation product made from bamboo strips,
known as laminated bamboo, has gained importance. The objective
of this research was to experiment the effect of three factors on the
mechanical property of laminated bamboo. The interested factors for
experimental design were (A) four bamboo species, namely Bambusa
blumeana Schultes (Pai See Suk), Dendrocalamus asper Backer (Pai
Tong), Dendrocalamus hamiltonii Nees (Pai Hok) and
Dendrocalamus sericeus Munro (Pai Sang Mon), (B) two types of
glue adhesive, polyvinyl acetate emulsion (PVAC) fortified with
urea-formaldehyde (UF) and urea-formaldehyde (UF) to make
parallel-oriented bamboo strips laminates and (C) glue weight per
strip area, 150 g/m2 and 190 g/m2. Experimental results showed that
Dendrocalamus asper Backer (Pai Tong) and Dendrocalamus
sericeus Munro (Pai Sang Mon) were best used for manufacturing
due to their highest MOR and MOE. The amount of glue weight 150
g/m2 yielded higher MOR and MOE than the amount of glue weight
190 g/m2. At the conclusion, the laminated bamboo manufacturers
can benefit from this research in order to select right materials
according to strength, cost and accessibility.
Abstract: Particle boards were prepared from Maize cob (MC) and urea-formaldehyde resin (UFR) on compression moulding machine. The amount of MC was varied from 50-120g while 30g of UFR was kept constant. Some mechanical properties of the particle boards were tested using the standard ASM methods. The results show that as the MC content increased from 50- 120g in 30g UFR, the hardness increased from about 6.89 x 102 to7.51 x 102MPa. Impact strength decreased from 3.3x 10-2 to 0.45 x 10-2J/M2, while tensile strength initially increased from 2.63 x 102 to 3.14 x 102 MPa as the MC increased from 50 to 60g in 30g UFR, thereafter, it decreased to about 1.35 x 102MPa at 120g in 30g content.
Abstract: In July 2012, an indoor/outdoor monitoring
programme was undertaken in two university sports facilities: a
fronton and a gymnasium. Comfort parameters (temperature, relative
humidity, CO and CO2) and total volatile organic compounds
(VOCs) were continuously monitored. Concentrations of NO2,
carbonyl compounds and individual VOCs were obtained. Low
volume samplers were used to collect particulate matter (PM10). The
minimum ventilation rates stipulated for acceptable indoor air quality
were observed in both sports facilities. It was found that cleaning
activities may have a large influence on the VOC levels. Acrolein
was one of the most abundant carbonyl compounds, showing
concentrations above the recommended limit. Formaldehyde was
detected at levels lower than those commonly reported for other
indoor environments. The PM10 concentrations obtained during the
occupancy periods ranged between 38 and 43μgm-3 in the fronton and
from 154 to 198μgm-3 in the gymnasium.