Nirundorn Matan

Improvement of the antifungal activity of Litsea cubeba vapor by using a helium–neon (He–Ne) laser against Aspergillus flavus on brown rice snack bars

The aim of this study was to improve the antifungal activity of the volatile Litsea cubeba essential oil and its main components (citral and limonene) on brown rice snack bars by applying He-Ne laser treatment. Different volumes (50-200 μL) of L. cubeba, citral or limonene were absorbed into a filter paper and placed inside an oven (18 L). Ten brown rice snack bars (2 cm wide × 4 cm long × 0.5 cm deep) were put in an oven and heated at 180 °C for 20 min. The shelf-life of the treated snack bars at 30 °C was assessed and sensory testing was carried out to investigate their consumer acceptability. A count of total phenolic content (TPC) and Fourier transform infrared spectroscopy (FTIR) on the properties of essential oil, citral, and limonene before and after the laser treatment was studied for possible modes of action. It was found that the laser treatment improved the antifungal activity of the examined volatile L. cubeba and citral with Aspergillus flavus inhibition by 80% in comparison with those of the control not treated with the laser. L. cubeba vapor at 100 μL with the laser treatment was found to completely inhibit the growth of natural molds on the snack bars for at least 25 days; however, without essential oil vapor and laser treatment, naturally contaminating mold was observed in 3 days. Results from the sensory tests showed that the panelists were unable to detect flavor and aroma differences between essential oil treatment and the control. Laser treatment caused an increase in TPC of citral oil whereas the TPC in limonene showed a decrease after the laser treatment. These situations could result from the changing peak of the aliphatic hydrocarbons that was revealed by the FTIR spectra.

Internal stress measurement during drying of rubberwood lumber: effects of wet-bulb temperature in various drying strategies

Abstract To understand internal stress (IS) development within lumber during drying of rubberwood, restoring force measurements on half-sawn specimens has been performed at drying temperature of 90°C under various patterns of wet-bulb (WB) temperature: (1) single-step drying, (2) two-step drying, (3) oscillation drying, and (4) stress control drying. Two extreme single-step drying conditions designated as “severe” and “conservative” at WB temperatures of 40°C and 80°C, respectively, were applied as control drying. It was shown that the measured force, which strongly correlates with the released strain data obtained by the McMillen slice test, indicates the level of IS developed within the lumber. In two-step drying, when the time of abrupt WB temperature change from conservative to severe drying conditions is extended up to the time of stress reversal, the force detected after stress reversal decreases from the level of severe drying to that of conservative drying. Once the time of stress reversal is exceeded, the force profile is largely unaffected by the parameters of the severe drying condition. Gradual reduction in WB temperature beyond the time of peak stress also reduces the force detected later after stress reversal under severe drying conditions. Oscillation of the WB temperature between conservative and severe conditions periodically changes the magnitude of the measured force. After stress reversal, the force amplitude monotonically decreases after each drying cycle. In addition, longer oscillation cycles seem to produce larger initial force amplitudes, which decline quicker than those created under the shorter ones. The possible application of the measured force as a controlling parameter of rubberwood drying has also been demonstrated.

Novel assessment of casehardening in kiln-dried lumber

Casehardening within kiln-dried rubberwood lumber was assessed by means of a novel restoring force measurement on a half-sawn specimen and a released strain according to the McMillen slice test. The techniques were used to quantify the magnitude of internal stress within the kiln-dried lumber during cooling and conditioning. It was revealed that cooling under relatively high humidity after drying is an effective technique to relieve the internal stress within the kiln-dried lumber during conditioning. The measured restoring force strongly correlated with the differential released strain between the surface and the core layers obtained from the McMillen slice test. The proposed technique showed good potential to be an alternative means to quantify the magnitude of internal stress within the kiln-dried lumber either during or after processing.

Magnetic properties of NdFeB-coated rubberwood composites

Magnetic properties of composites prepared by coating lacquer containing neodymium iron boron (Nd-Fe-B) powders on rubberwood were characterized by vibrating sample magnetometry (VSM), magnetic moment measurements, and attraction tests with an iron-core solenoid. The Nd-Fe-B powders were recycled from electronic wastes by the ball-milling technique. Varying the milling time from 20 to 300 min, the magnetic squareness and the coercive field of the Nd-Fe-B powders were at the minimum when the powders were milled for 130 min. It followed that the coercive field of the magnetic wood composites was increased with the milling time increasing from 130 to 300 min. For the magnetic wood composites using Nd-Fe-B obtained from the same milling time, the magnetic squareness and the coercive field were rather insensitive to the variation of Nd-Fe-B concentration in coating lacquer from 0.43 to 1.00 g/cm3. By contrast, the magnetization and magnetic moment were increased with the Nd-Fe-B concentration increasing. Furthermore, the electrical current in the solenoid required for the attraction of the magnetic wood composites was exponentially reduced with the increase in the amount of Nd-Fe-B used in the coating.

Property gradients in oil palm trunk ( Elaeis guineensis )

Since the structure of oil palm wood varies dramatically, the property gradients of oil palm wood within a trunk are of great interest. In this study, the physical (density, water uptake and swelling in the radial direction) and mechanical properties (bending modulus of elasticity and strength, compressive modulus of elasticity and strength in the direction parallel to the fiber, compressive strength in the direction perpendicular to the fiber and shear strength in the direction parallel to the fiber) of oil palm wood for a whole trunk were examined. The water uptake, compressive strength in the direction perpendicular to the fiber, shear strength in the direction parallel to the fiber, bending modulus of elasticity and strength and compressive modulus of elasticity and strength in the direction parallel to the fiber appeared to be independent of trunk height but tended to be related to the relative distance from surface or density by a single master curve. However, the swelling in the radial direction of the oil palm wood was not correlated with the relative distance from the surface, trunk height or density. Finally, property map of oil palm wood for a cross section at any height was prepared for practical use.

Activated Carbon for Food Packaging Application: Review

This was a descriptive research aiming at investigating the quality of life of the Royal Thai Navy College of Nursing’s (RTNCN) personnel. There were 325 samples which were from the executives, nursing instructors, supporting staff and nursing students in the academic year 2014. The research tool was the World Health Organization Quality of Life assessment (WHOQOL - BRIEF - THAI) and the reliability of which was tested using the Cronbach’s Alpha with the result at 0.91. The statistics applied in this study were descriptive statistic. The results were as follows: 1) The Quality of Life in the aspects of physical health, psychological state, environment and overview of Quality of Life were mainly at moderate level (66.77, 54.77, 45.54, 75.38 and 57.85 percent respectively); and 2) Analyzing the Mean, it was found that QOL in all aspects of the personnel was at moderate level.