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11.
《Drying Technology》2007,25(7):1275-1280
When using the convective drying method, the mass transfer between drying air and moisture diffusion of the material is very important. The moisture moves inside the material because of the volume change caused by the increased temperature. This movement is additionally affected by the texture of the material. According to the research dealing with colloid capillary porous texture of vegetables and fruit, the humidity migration inside the material occurs in both fluid and steam condition at the same time. This migration is stimulated by the heating and decreasing humidity along with the flow. In this research, winter varieties of apples (Jonathan, Golden Delicious, and Idared) were studied by heating of a 20 × 20 × 20 piece of apple with a thermocouple in it. On the basis of the measurements it can be stated that for the fruits with a high percentage of moisture (75-90%), when making the drying condition, the moisture gradient is influenced by the fractured cells of the cut area. It was found that the variety of apple is very important in relation to the heating and water loss gradient. According to the results, the wet volume change due to the heating highly influences the water loss. The models that describe the temperature of the material have a connection with the water loss. 相似文献
12.
Water extracts of giant foxtail grass inhibited germination and radicle elongation of loblolly pine seed in a laboratory test. Most of the toxic effects came from extracts of dried foxtail tops, with lesser amounts from fresh tops and roots. Soil texture affected the phytotoxicity of the extracts. Eight chemical compounds known to be phytotoxins inSetaria were identified in extracts of foxtail leaves but could not be found in soil samples under the leaves. 相似文献
13.
A. Goyal E. D. Specht Z. L. Wang D. M. Kroeger J. A. Sutliff J. E. Tkaczyk J. A. Deluca L. Masur G. N. Riley 《Journal of Electronic Materials》1994,23(11):1191-1197
Microstructural origins for reduced weak-link behavior in high-Jc melt-processed YBCO, spray pyrolyzed thick films of Tl-1223, metallic precursor Y-124 polycrystalline powder-in-tube (PIT)
wires and PIT Bi-2212/2223 are discussed. Since the materials studied are the highest Jc, polycrystalline, high-Tc superconductors fabricated worldwide, the results provide important guidelines for further improvements in superconducting
properties, thereby enabling practical applications of these materials. It is found that strongly linked current flow within
domains of melt-processed 123 occurs effectively through a single crystal path. In c-axis oriented, polycrystalline Tl-1223
thick films, local in-plane texture has been found to play a crucial role in the reduced weak-link behavior. Formation of
“colonies” of grains with a common c-axis and modest in-plane misorientation was observed. Furthermore, a colony boundary
in general has a varying misorientation along the boundary. Large regions comprised primarily of low angle boundaries were
observed. Percolative transport through a network of such small angle boundaries appears to provide the nonweak-linked current
path. Although powder-in-tube BSCCO 2212 and 2223 also appear to have a “colony” microstructure, there are some important
differences. Colonies in BSCCO consist of stacks of grains with similar c-axis orientation in contrast to colonies in Tl-1223
films where few grains are stacked on top of one another. Furthermore, most grains within a colony in BSCCO have the same
lateral dimensions as that of the colony, resulting largely largely in “twist” boundaries. Further microstructural characterization
of high-Jc PIT 2212 and 2223 is currently underway. In the case of Y-124 wires, weak macroscopic in-plane texture is found. Additional
measurements are underway to determine if a sharper, local in-plane texture also exists. It is found that in three of the
four types of superconductors studied, reduced weak-link behavior can be ascribed to some degree of biaxial alignment between
grains, either on a “local” or a “global” scale. 相似文献
14.
~~Growth of CeO_2, Y_2O_3 Buffer Layers for YBCO Coated Conductor 相似文献
15.
Effect of pretreatments and freezing rate on the firmness of potato tissue after a freeze–thaw cycle
Sergio Carbonell Jorge C. Oliveira & Alan L. Kelly 《International Journal of Food Science & Technology》2006,41(7):757-767
The texture of potato tissue after a freeze–thaw process using different freezing rates and different pretreatments was analysed, in order to select the best strategy for optimum preservation of the textural characteristics of pre‐frozen potato. Ten blanching conditions were tested and a two‐step blanching process with calcium chloride (0.07 g mL?1) proved the most effective in protecting the tissue after a freeze–thaw process (maximum load force around 10–55% of the raw tissue, depending on potato batch, for air‐blast freezing and 20–60% for immersion freezing). Vacuum impregnation at 100 and 400 mbar, even when followed by different pre‐drying treatments to remove excess water, was very detrimental to resistance to a freeze–thaw process (maximum load force below 10% of the raw tissue for air‐blast freezing and below 20% for immersion freezing). Microstructure analysis confirmed better tissue integrity retention with ethyleneglycol immersion freezing instead of air‐freezing. Differences were found between batches with a 6‐month difference in storage time, indicating that the fresher batch was more suitable for freezing. 相似文献
16.
SEBASTIANO PORRETTA † GIUSEPPE CARPI GIANFRANCO DALL'AGLIO CLAUDIO GHIZZONI 《International Journal of Food Science & Technology》1992,27(4):427-433
The characteristics of high-quality tomato pulp (commercial def.: crushed or diced tomatoes with about 30% tomato juice as packing medium) canned with tomato juice pulp enriched by ultrafiltration as packing medium were compared with those covered with conventional vacuum-concentrated juice.
Both hot- and cold-break products were prepared and those containing 20% serum-reduced packing juice proved to be the best, showing no signs of syneresis on storage and with improvements in sensory properties, colour and non-enzymatic browning; some volatile components were reduced. 相似文献
Both hot- and cold-break products were prepared and those containing 20% serum-reduced packing juice proved to be the best, showing no signs of syneresis on storage and with improvements in sensory properties, colour and non-enzymatic browning; some volatile components were reduced. 相似文献
17.
Wood inspection with non-supervised clustering 总被引:9,自引:0,他引:9
Abstract. The appearance of sawn timber has huge natural variations that the human inspector easily compensates for mentally when determining
the types of defects and the grade of each board. However, for automatic wood inspection systems these variations are a major
source for complication. This makes it difficult to use textbook methodologies for visual inspection. These methodologies
generally aim at systems that are trained in a supervised manner with samples of defects and good material, but selecting
and labeling the samples is an error-prone process that limits the accuracy that can be achieved. We present a non-supervised
clustering-based approach for detecting and recognizing defects in lumber boards. A key idea is to employ a self-organizing
map (SOM) for discriminating between sound wood and defects. Human involvement needed for training is minimal. The approach
has been tested with color images of lumber boards, and the achieved false detection and error escape rates are low. The approach
also provides a self-intuitive visual user interface.
Received: 16 December 2000 / Accepted: 8 December 2001
Correspondence to: O. Silvén 相似文献
18.
19.
S. Zaefferer 《Advanced Engineering Materials》2003,5(8):607-613
In recent years the investigation of local texture and microstructure by analysis of electron backscatter diffraction patterns (EBSP) in the SEM has become a very powerful and popular method. With the introduction of SEM with field emission guns (FEG) the spatial resolution of EBSP measurements could be enhanced from 500 nm with a tungsten emitter to better than 50 nm. This evolution of SEM techniques raises the question whether transmission electron microscopy (TEM) still has fields of application in texture research. The present article answers this question with a clear “yes” and presents three examples of investigations where TEM is indispensable. The three examples comprise the investigation of the correlation between dislocation structure and deformation texture, a study on nucleation mechanisms of recrystallization in highly deformed metals and the investigation of microtexture and microstructure in nanocrystalline materials. Together with the presentation of these cases some of the necessary measurement techniques are described briefly. It is shown that TEM has to be applied when highest spatial resolution of orientation determination and imaging and high accuracy of orientation determination are to be reached, when the three‐dimensional and quantitative characterization of lattice defects is required or when materials with a high density of lattice defects are to be investigated. 相似文献
20.
Real-time homogenous translucent material editing 总被引:4,自引:0,他引:4
This paper presents a novel method for real-time homogenous translucent material editing under fixed illumination. We consider the complete analytic BSSRDF model proposed by Jensen et al. [ [JMLH01] ], including both multiple scattering and single scattering. Our method allows the user to adjust the analytic parameters of BSSRDF and provides high-quality, real-time rendering feedback. Inspired by recently developed Precomputed Radiance Transfer (PRT) techniques, we approximate both the multiple scattering diffuse reflectance function and the single scattering exponential attenuation function in the analytic model using basis functions, so that re-computing the outgoing radiance at each vertex as parameters change reduces to simple dot products. In addition, using a non-uniform piecewise polynomial basis, we are able to achieve smaller approximation error than using bases adopted in previous PRT-based works, such as spherical harmonics and wavelets. Using hardware acceleration, we demonstrate that our system generates images comparable to [ [JMLH01] ]at real-time frame-rates. 相似文献