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221.
L. Miettinen P. Kekäläinen J. Merikoski J. Timonen 《International Journal of Thermophysics》2009,30(6):1902-1917
The transient fin model introduced recently for determination of the in-plane thermal diffusivity of planar samples with the
help of infrared thermography was modified so as to be applicable to poor heat conductors. The new model now includes a temperature-dependent
heat loss by convective heat transfer, suitable for an experimental setup in which the sample is aligned parallel to a weak,
forced air flow stabilizing otherwise the convective heat transfer. The temperature field in the sample was measured with
an infrared camera while the sample was heated at one edge. The symmetric temperature field created was averaged over the
central fifth of the sample to obtain one-dimensional temperature profiles, both transient and stationary, which were fitted
by a numerical solution of the fin model. One of the fitting parameters was the thermal diffusivity, and with a known density
and specific heat capacity, the thermal conductivity was thus determined. The test measurements with tantalum samples gave
the result (57.5 ± 0.2) W · m−1 · K−1 in excellent agreement with the known value. The other fitting parameter was a temperature-dependent heat loss coefficient
from which the lower limit for the temperature-dependent convection coefficient was determined. For the stationary state the
result was (1.0 ± 0.2) W · m−2 · K−1 at the temperature of the flowing air, and its temperature dependence was found to be (0.22 ± 0.01) W ·m−2 · K−2. 相似文献
222.
Soottitantawat Apinan Ikuta Yujiro Yoshii Hidefumi Furuta Takeshi Pivi Myllrinen Pirkko Forssell Kaisa Poutanen 《Starch - St?rke》2007,59(11):543-548
Porous starch was produced by digestion of freeze‐dried potato starch with α‐amylase from Bacillus sp. The surface structure of the granules became perforated and in the interior of the granules a capsule‐like cavity was formed, i.e. the hydrolyzed starch can be used as an encapsulant. The structure change of the granules was observed with confocal laser scanning microscopy and scanning electron microscopy. The degree of starch hydrolysis could be correlated with the Avrami equation. The activation energy of starch hydrolysis by α‐amylase was 83 kJ/mol. 相似文献
223.
Native and freeze‐dried potato starch granules were partially hydrolysed to produce maltodextrins with dextrose equivalents (DE) 10, 15 and 20. Freeze‐drying greatly improved the enzyme accessibility of the native granules. Film formation properties of the hydrolysates were examined. Films were prepared by water casting. Especially the maltodextrins, which were produced from the native starch, were very sticky materials and could not form any films. But after removing most of the soluble saccharides from the maltodextrins, good quality films were produced by dissolving the hydrolysate in water, casting on a Teflon mould and drying the solution. 相似文献
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226.
Biomass burning in humid tropical Southeast Asia causes haze problems, environmental degradation and economic losses. These fires have often been connected to land clearance and changes in land cover. This study investigates the relationship between fire and land cover change in humid tropical Southeast Asia. The analysis is based on three sets of land cover classifications and burnt area detections (1998, 2000 and 2002), based on SPOT 2 HRV and SPOT 4 HRVIR images. The results indicate that the connection between land cover change and fire is highly dependent on land cover type. There is a strong correlation between land cover change and fire in the primary vegetation and a slightly weaker correlation in the secondary growth. More than 90% of the severely burnt primary vegetation areas and 45% of the severely burnt secondary growth resulted in land cover type change during the study. Fire is extensively used for conversion on the aforementioned land cover types. In the managed land cover types fire does not have any correlation with land cover changes. This study also revealed substantial land cover changes in the study area. The primary vegetation areas diminish by approximately 5% per year, while the managed land cover types consistently increase their areas. 相似文献
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229.
Adam Macierzanka François Bordron Neil M. Rigby E.N. Clare Mills Martina Lille Kaisa Poutanen Alan R. Mackie 《Food Hydrocolloids》2011
Enzymatic cross-linking is an important method of modifying the structure of food products to control their texture and stability. In this paper we look at the effect that adsorption to the oil–water interface of triglyceride oil-in-water emulsion has on rates of cross-linking of sodium caseinate by microbial transglutaminase. The kinetics of cross-linking has also been assessed for the individual casein proteins within the caseinate. In solution the rates were αs2-casein > β-casein > αs1-casein > κ-casein. This order is not as expected given the rheomorphic nature of the proteins and the number of glutamine and lysine residues in each protein. In particular, the αs1-casein was cross-linked much more slowly than expected. When sodium caseinate was adsorbed to an emulsion the rates for all constituent caseins were decreased but the cross-linking rate for αs1-casein was markedly reduced, indicating the most significant change in accessibility following adsorption. This knowledge will facilitate optimal production of cross-linked emulsions for use in future studies aimed at engineering emulsions with improved nutritional quality. 相似文献
230.
Interactive methods are useful and realistic multiobjective optimization techniques and, thus, many such methods exist. However,
they have two important drawbacks when using them in real applications. Firstly, the question of which method should be chosen
is not trivial. Secondly, there are rather few practical implementations of the methods. We introduce a general formulation
that can accommodate several interactive methods. This provides a comfortable implementation framework for a general interactive
system. Besides, this implementation allows the decision maker to choose how to give preference information to the system,
and enables changing it anytime during the solution process. This change-of-method option provides a very flexible framework
for the decision maker. 相似文献