scholarly journals Dielektrické vlastnosti zemědělských produktů a některé jejich aplikace

2008 ◽  
Vol 54 (No. 2) ◽  
pp. 104-112 ◽  
Author(s):  
S.O Nelson
Keyword(s):  
Dielectric Properties ◽  
Moisture Content ◽  
Radio Frequency ◽  
Fruits And Vegetables ◽  
Agricultural Products ◽  
Dielectric Heating ◽  
Quality Factors ◽  
Poultry Products ◽  
Microwave Dielectric ◽  
Microwave Dielectric Heating

The use of dielectric properties of agricultural products for sensing moisture in grain and seed and their application in radio-frequency and microwave dielectric heating is discussed briefly. Values for the dielectric properties of a number of products, including grain and seed, fruits and vegetables, and poultry products, are presented graphically to show the dependence of these properties on frequency, moisture content, and temperature. The potential for using the dielectric properties to sense quality factors other than moisture content is also considered.

scholarly journals Effects of Moisture, Temperature, and Salt Content on the Dielectric Properties of Pecan Kernels During Microwave and Radio Frequency Drying Processes

Foods ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 385 ◽  
Author(s):  
Zhang ◽  
Li ◽  
Cheng ◽  
Wang ◽  
Ding ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Moisture Content ◽  
Radio Frequency ◽  
Salt Content ◽  
Rf Heating ◽  
Dielectric Heating ◽  
Time Histories ◽  
Properties Of Materials ◽  
Content Range ◽  
Temperature Time

Dielectric properties of materials influence the interaction of electromagnetic fields with and are therefore important in designing effective dielectric heating processes. We investigated the dielectric properties (DPs) of pecan kernels between 10 and 3000 MHz using a Novocontrol broadband dielectric spectrometer in a temperature range of 5–65 °C and a moisture content range of 10–30% wet basis (wb) at three salt levels. The dielectric constant (ε′) and loss factor (ε′′) of the pecan kernels decreased significantly with increasing frequency in the radio frequency (RF) band, but gradually in the measured microwave (MW) band. The moisture content and temperature increase greatly contributed to the increase in the ε′ and ε′′ of samples, and ε′′ increased sharply with increasing salt strength. Quadratic polynomial models were established to simulate DPs as functions of temperature and moisture content at four frequencies (27, 40, 915, and 2450 MHz), with R2 > 0.94. The average penetration depth of pecan kernels in the RF band was greater than that in the MW band (238.17 ± 21.78 cm vs. 15.23 ± 7.36 cm; p < 0.01). Based on the measured DP data, the simulated and experimental temperature-time histories of pecan kernels at five moisture contents were compared within the 5 min RF heating period.

scholarly journals Synthesis of 2-Substitued Indoles via Pd-Catalysed Cyclization in an Aqueous Micellar Medium

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3917
Author(s):  
Sofia Siciliano ◽  
Elena Cini ◽  
Maurizio Taddei ◽  
Giorgia Vinciarelli
Keyword(s):  
Water Environment ◽  
Delivery Mode ◽  
Micellar Medium ◽  
Dielectric Heating ◽  
Microwave Dielectric ◽  
Microwave Dielectric Heating ◽  
Heating Mode ◽  
Aqueous Micellar Medium ◽  
By Products ◽  
Better Than

The synthesis of 2-substituted indoles starting from the corresponding unprotected 2-alkynylanilines was made possible in 3% TPGS-750-M water using Pd(OAc)2 alone as the catalyst. The reaction was sensitive to the heating mode respect to the nature of the starting material as, in many cases, convectional heating was better than microwave dielectric heating. The MW (microwave) delivery mode had also an influence in the formation of by-products and, consequently, product yields. A tandem Sonogashira-cyclisation reaction was also accomplished using Pd(OAc)2/Xphos in the nanomicellar water environment.

Synthesis of Diaryl Ethers, Diaryl Sulfides, Heteroaryl Ethers and Heteroaryl Sulfides under Microwave Dielectric Heating.

ChemInform ◽  
2005 ◽  
Vol 36 (43) ◽  
Author(s):  
Feng Li ◽  
Qingqing Meng ◽  
Huansheng Chen ◽  
Zhiming Li ◽  
Quanrui Wang ◽  
...  
Keyword(s):  
Dielectric Heating ◽  
Diaryl Ethers ◽  
Microwave Dielectric ◽  
Microwave Dielectric Heating

Microwave dielectric properties and applications of rare-earth aluminates

1999 ◽  
Vol 14 (1) ◽  
pp. 114-119 ◽  
Author(s):  
Seo-Yong Cho ◽  
In-Tae Kim ◽  
Kug Sun Hong
Keyword(s):  
Rare Earth ◽  
Dielectric Properties ◽  
Microwave Dielectric Properties ◽  
Microstrip Antennas ◽  
Substrate Material ◽  
Rhombohedral Structure ◽  
Quality Factors ◽  
Microwave Dielectric ◽  
Ionic Size ◽  
The Difference

Rare-earth aluminates, LnAlO3 (Ln = Dy, Er, Gd, La, Nd, Pr, Sm, and Y) were prepared using the mixed oxide method, and their microwave dielectric properties were examined at X-band. Most rare-earth aluminates have suitable permittivities and quality factors for applications as dielectric resonators, but a modification of τf is necessary due to the coefficient's large negative value. When considering dielectric properties and lattice matching, YalO3 rather than LaAlO3, was suggested as a promising substrate material for microstrip antennas utilizing high-temperature superconductor thin films. Rare-earth aluminates with a rhombohedral structure exhibited larger permittivities than those with an orthorhombic structure. This difference was attributed to the difference in ionic size and coordination number. It was demonstrated that a nonzero magnetic susceptibility of rare-earth aluminates has an adverse effect on their quality factor. An abrupt variation in the temperature coefficient of permittivity was discussed in terms of oxygen octrahedra tilting.

Increasing Legume Seed Germination by VHF and Microwave Dielectric Heating

1976 ◽  
Vol 19 (2) ◽  
pp. 0369-0371 ◽  
Author(s):  
S. O. Nelson ◽  
L.A. T. Ballard ◽  
L. E. Stetson ◽  
T. Buchwald
Keyword(s):  
Seed Germination ◽  
Dielectric Heating ◽  
Legume Seed ◽  
Microwave Dielectric ◽  
Microwave Dielectric Heating
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