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Silo bags have been used by Canadian farmers in the last few years to temporarily store cereal grains, pulses, and oilseeds for up to one year. It is difficult to install temperature and moisture cables inside silo bags or conduct sampling because any cutting of the silo bag damages its hermeticity. Mathematical models could be used to predict spoilage during storage, and the accuracy of mathematical models is influenced by soil temperature. In this study, soil temperature models were developed based on the energy balance on the surface of the ground and heat conduction equations (HCE). The surface of the ground was covered with snow during winter and with vegetation during summer. The developed soil models were coupled with the developed three-dimensional transient heat, mass, and momentum transfer models inside silo bags. The developed models were validated using weather data (solar radiation, temperature, relative humidity, wind speed, and snow covering) and temperatures collected inside bulk canola in silo bags with 9.1% and 10.5% moisture contents. The prediction accuracy associated with the HCE models was compared with that associated with Fourier series, which has been used in the literature. The HCE models developed in this study had higher prediction accuracy than the Fourier series. The maximum absolute difference and average absolute difference between the measured and predicted (by the HCE models) canola temperature at 10 cm height of the canola from the bottom of the silo bag were 3.23°C and <1.79°C ±0.04°C, respectively. [ABSTRACT FROM AUTHOR]

A three-dimensional transient heat, mass, and momentum transfer model was developed to predict temperatures and moisture contents of canola stored inside silo bags under Canadian Prairie conditions. The developed model calculated the condensation and production of water and heat generated by the respiration of microorganisms inside silo bags. This model was coupled with the soil temperature model developed in part I. These developed models were validated using weather data as input and measured temperatures and moisture contents inside silo bags filled with canola at 9.1%, 10.5%, or 14.4% initial moisture content (MC). The developed models had a poor prediction of the temperature and moisture content of the 14.4% MC canola because the canola seeds spoiled and clumped together in less than four months. The developed models could explain more than 90% of the measured temperatures inside the silo bags filled with 10.5% MC canola without underestimation or overestimation. The average absolute difference was less than 1.9°C ±0.1°C and 0.7°C ±0.0°C inside silo bags with 9.1% and 10.5% initial MC, respectively. The developed models could explain more than 94% of the measured moisture contents of canola stored inside the silo bags with ≤10.5% initial MC. The average absolute difference between measured and predicted moisture contents of canola was ≤0.4% ±0.0% inside the silo bags filled with 9.1% and 10.5% MC canola. Simulation results showed that condensation on the canola seeds mostly occurred at the boundary of silo bags, and canola inside hot spots might produce ≥2.5 fold of heat production, which was measured under small-scale laboratory conditions. [ABSTRACT FROM AUTHOR]

The thermal properties of mung bean (Vigna radiata) are essential for designing postharvest handling equipment for mung bean processing. The specific heat, thermal conductivity, and thermal diffusivity of mung bean were determined as a function of moisture content and temperature. The specific heat and thermal conductivity were quantified using a specially built vacuum flask calorimeter and thermal conductivity probe, respectively. The specific heat was determined by mixing hot water with a sample maintained at lower temperature and incorporating graphical temperature-correction into the calculation. The thermal conductivity was determined by measuring the temperature response of the sample when heated with a line heat source. The thermal diffusivity was directly calculated from the specific heat and thermal conductivity data. The specific heat and thermal conductivity of mung bean increased linearly from 1.63 to 2.45 kJ kg-1 K-1 and from 0.092 to 0.141 W m-1 K-1 respectively, with the corresponding increase in moisture content from 9.9% to 18.3% w.b. and temperature from 10°C to 50°C. The thermal diffusivity of mung bean changed from 0.659 x 107-7 to 0.752 x 10-7 m² s-1 with increase in moisture content and temperature. The thermal diffusivity increased with increase in moisture content and decreased with increase in temperature. [ABSTRACT FROM AUTHOR]

The major drawback associated with microwave heating is the non-uniform temperature distribution. Temperature distribution studies have shown that various materials behave differently during microwave heating. A pilot-scale industrial microwave dryer operating at 2450 MHz was used to heat grains and oilseed. An infra-red thermal camera was used in this study to determine the temperature distribution in bulk rye and oats at 14, 16, and 18% moisture content (wet basis) and sunflower seeds at 8, 10, and 12% moisture content after being heated in the microwave drier. Fifty grams of grain were placed in a sample holder and allowed to pass on a conveyor belt under the applicator at 0, 200, 300, 400, and 500 W for 28 or 56 s. There were hot and cool regions in the samples. The temperature difference between hot and cool regions in a given sample varied between 23 and 62°C for rye, 7 and 25°C for oats and 7 and 29°C for sunflower seeds. The preliminary results of this study suggest that while using microwave as a heat treatment, the maximum temperature that can affect seed viability (potential to germinate under favorable conditions) should be taken into consideration, when developing microwave processing systems for grains and oilseeds. [ABSTRACT FROM AUTHOR]

Investigation of the highly polar chemical constituents in the stem of Hopea parviflora (Dipterocarpaceae) resulted in the isolation of four new resveratrol derivatives, hopeasides A and B (1, 2) (resveratrol pentamers), C (3) (resveratrol trimer), and D (4) (resveratrol dimer) together with nine known resveratrol oligomers (5-13). The new structures have a common partial structure of the 1-hydroxy-1-(3,5-dihydroxy-2-C-glucopyranosylphenyl)-2-(4-hydroxyphenyl)ethane-2-yl group after oxidative condensation of (E)-resveratrol-10-C-β-glucopyranoside (14). The structures were determined by spectroscopic analysis including 2D-NMR and computer-aided molecular modeling. The biogenetic relationship of the isolates and NMR characteristics caused by steric hindrance are also discussed in this paper., (© 2011 Pharmaceutical Society of Japan)

Comprehensive re-investigation of the chemical constituents in the leaves of Vateria indica (Dipterocarpaceae) resulted in the isolation of a novel resveratrol dimeric dimer having a C(2)-symmetric structure, vateriaphenol F (1), and two new O-glucosides of resveratrol oligomers, vateriosides A (2) (resveratrol dimer) and B (4) (resveratrol tetramer), along with a new natural compound (3) and 33 known compounds including 26 resveratrol derivatives. The absolute structures were elucidated by spectroscopic analysis, including two dimensional NMR and circular dichroism (CD) spectra.