High temperature contact treatment of hard seed in Stylosanthes

1979 ◽  
Vol 30 (5) ◽  
pp. 847 ◽  
Author(s):  
JJ Mott
Keyword(s):  
High Temperature ◽  
High Surface ◽  
Contact Period ◽  
Rotating Drum ◽  
Optimum Temperature ◽  
Hard Seed ◽  
Stylosanthes Humilis ◽  
Seed Content ◽  
Metal Plates ◽  
Palisade Cells

Samples of hard seed of Stylosanthes humilis, S. hamata, S. scabra and S. viscosa were agitated on high temperature metal plates in order to reduce the hard seed content. The optimum temperature for reduction of hard seed was found to be 140–150°C, with a contact period of 15–30 s, and hard seed content was reduced by up to 70%. Internal seed temperatures generally remained below 70° during this treatment, and there was little loss of viability. As with percussion treatments, imbibition took place through the strophiole, which indicates that break of hard seed occurred by mechanical stresses fracturing the palisade cells at the strophiole. On the basis of this principle of high surface temperatures and brief seed contact, a heated rotating drum was constructed and successfully used to treat bulk quantities of hard seed.

scholarly journals Parameters of temperature disturbance triggering the propagation of the quench front on an extremely overheated surface

2021 ◽  
Vol 2119 (1) ◽  
pp. 012079
Author(s):  
I P Starodubtseva ◽  
A N Pavlenko
Keyword(s):  
Experimental Data ◽  
High Temperature ◽  
Front Propagation ◽  
Solid Contact ◽  
Temperature Disturbance ◽  
Metal Plates ◽  
Leidenfrost Temperature ◽  
Dynamical Pattern ◽  
Temperature Surface

Abstract The results of computational experiments simulating the triggering of the quench front propagation on the superheated vertically oriented metal plates are presented. The plates are quenched by a gravitationally flowing down liquid nitrogen film. The temperature of the test samples at the beginning of the process was higher than the critical temperature and the Leidenfrost temperature, which means that direct long-term liquid-solid contact is impossible. For this reason, the front is initially motionless. As a result of numerical simulation, a dynamic pattern of the quench front propagation on a high-temperature surface was obtained. Analysis of the results allowed to find the realistic values of heat sink into the cooling medium, as well as the parameters of the local temperature disturbance, its spatial extent and amplitude, at which the conditions are created for triggering the process of quench front propagation on the high-temperature surface. Direct comparison of the numerical simulations results with experimental data on the velocity, geometry of the quench front and on the dynamical pattern of the process confirmed the reliability of the results obtained.

scholarly journals Studies on the variation and inheritance of the hard seed content of Renge (Astragalus sileicus L, ).

1963 ◽  
Vol 13 (1) ◽  
pp. 21-24 ◽  
Author(s):  
Katsumi SYAKUDO ◽  
Syutaro KAWABATA ◽  
Motoi MURATA
Keyword(s):  
Hard Seed ◽  
Seed Content

Design and Calibration of a Novel High Temperature Heat Flux Gage

2005 ◽  
Author(s):  
Sujay Raphael-Mabel ◽  
Scott Huxtable ◽  
Andrew Gifford ◽  
Thomas E. Diller
Keyword(s):  
Heat Flux ◽  
High Temperature ◽  
High Heat ◽  
Heat Flux Sensor ◽  
High Heat Flux ◽  
Average Value ◽  
Metal Plates ◽  
New Type ◽  
Flux Sensor ◽  
Calibration Apparatus

A new type of heat flux sensor (HTHFS) has been designed and constructed for applications at high temperature and high heat flux. It is constructed by connecting solid metal plates to form brass/steel thermocouple junctions in a series circuit. The thermal resistance layer of the HTHFS consists of the thermocouple materials themselves, thus improving temperature limits and lowering the temperature disruption of the sensor. The sensor can even withstand considerable erosion of the surface with little effect on the operation. A new type of convection calibration apparatus was designed and built specifically to supply a large convection heat flux. The heat flux was supplied simultaneously to both a test and standard gage by using two heated jets of air that impinged perpendicularly on the surface of each gage. The sensitivity for the HTHFS was measured to have an average value of 20 μV/(W/cm2). The uncertainty in this result was determined to be ±10% over the entire range tested. The sensitivity agrees with the theoretically calculated sensitivity for the materials and geometry used. Recommendations for future improvements in the construction and use of the sensors are discussed.

Synthesis and Characterization of Aerogel-derived Cation-substituted Hexaaluminates

1996 ◽  
Vol 457 ◽  
Author(s):  
Lin-chiuan Yan ◽  
Levi T. Thompson
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Catalytic Combustion ◽  
High Surface ◽  
High Surface Area ◽  
Synthesis And Characterization ◽  
New Methods ◽  
Surface Areas ◽  
Different Characteristics

ABSTRACTNew methods have been developed for the synthesis of high surface area cation-substituted hexaaluminates. These materials were prepared by calcining high temperature (ethanol extraction) or low temperature (CO2 extraction) aerogels at temperatures up to 1600°C. Cation-substituted hexaaluminates have emerged as promising catalysts for use in high temperature catalytic combustion. In comparing unsubstituted and cation-substituted hexaaluminates, we found that the phase transformations were much cleaner for the cation-substituted materials. BaCO3 and BaAl2O4 were intermediates during transformation of the unsubstituted materials, while the cation-substituted materials transformed directly from an amorphous phase to crystalline hexaaluminate. Moreover, the presence of substitution cations caused the transformation to occur at lower temperatures. Mn seems to be a better substitution cation than Co since the Mn-substituted materials exhibited higher surface areas and better heat resistances than the Co-substituted materials. The low temperature aerogel-derived materials possessed quite different characteristics from the high temperature aerogel-derived materials. For example, phase transformation pathways were different.

scholarly journals Linking the Effect of Aggregate Interaction to the Compaction Theory for Asphalt Mixtures Using Image Processing

2018 ◽  
Vol 8 (11) ◽  
pp. 2045 ◽  
Author(s):  
Kyoungchul Kim ◽  
Myungook Kang
Keyword(s):  
Image Processing ◽  
High Temperature ◽  
Asphalt Binder ◽  
Asphalt Mixtures ◽  
Energy Index ◽  
Optimum Temperature ◽  
Frictional Behavior ◽  
Viscosity Effect ◽  
Frictional Interaction ◽  
Compaction Energy

This study presents a modified compaction concept of asphalt mixtures based on aggregate frictional behavior using self-developed image processing for measuring the aggregate orientation. The compaction energy index was introduced to evaluate the aggregate orientation on different compaction temperatures. For the better rearrangement of aggregates, there was an optimum temperature at which a preferred orientation exists, providing lower compaction efforts. An excessively high temperature reduced the asphalt contents for lubrication and caused additional aggregate friction to require higher compaction efforts. This phenomenon can be found in the changes of the volume of the effective asphalt binder (Veac) and the absorbed asphalt binder (Pba). The mixture produced higher Veac, at which an optimum compaction temperature required lower compaction energy. Despite being higher than the optimum temperature for the PG62-28 mixture, the Veac decreased by 0.4%. An increase of 0.35% in the Pba was inferred to flow into the aggregates. Clearly, a reduction of lubricant in the mixture caused a higher frictional interaction between aggregates. Changes in the Veac and the Pba can eliminate the viscosity effect for the rearrangement of aggregates. Based on the aggregate orientation and change in mixture volumetrics, the aggregate interaction effect was introduced to the Mohr–Coulomb compaction theory to explain the additional friction.

Sign in / Sign up

Export Citation Format

Share Document