scholarly journals Dielectric properties of deformed early potatoes

2008 ◽  
Vol 54 (No. 2) ◽  
pp. 113-122
Author(s):  
J. Blahovec

The permittivity of potato tissue was studied during uniaxial compression of cylindrical specimens prepared from two early varieties. Both the real and the imaginary permitivity components were determined repeatedly during the loading and unloading tests. The analysis of the results obtained shows that small differences exist between the permittivity of the late and early potato varieties. The differences are concentrated mainly at frequencies higher than 1 kHz with a maximum between 10 and 100 kHz. The effect of deformation is concentrated into frequencies between 1 and 100 kHz. The effect of deformation on the permittivity values can be divided into reversible and irreversible parts. The results obtained in the loading/unloading tests give some more information on the proportion of both parts.

2020 ◽  
pp. 31-38
Author(s):  
MARINA E. DIYKANOVA ◽  
◽  
ALEKSANDR G. LEVSHIN ◽  
IRINA N. GASPARYAN ◽  
NATALIA F. DENISKINA ◽  
...  

In the Moscoww region, frosts are quite probable to return until the fi rst decade of June. To protect potatoes from the returning cold weather, it is possible to use a temporary covering material in the “planting – seedling emergence” period. The authors have studied the use of covering materials on early potato varieties of Udacha, Zhukovsky early, Red Scarlet, Snegir’, and Meteor. Studies have been conducted on the test plot of the Vegetable Growing Department of Russian State Agrarian University – Moscow Timiryazev Agricultural Academy in 2017-2019. Non-woven white and black material of the same density of 17 g/m2 was used for covering. No covering was used in the check variant. The cultivation technology was standard,it included tillage (plowing, spring tillage, and cutting ridges before planting), as well as plant care (inter-row cultivation and hilling-up). Planting was carried out with a single-row potato planter. The earliest emergence of seedlings was observed under white covering material with a diff erence of 5-6 days in relation to the check variant. In the variant with a black covering material, the diff erence averaged 3-4 days. Due to covering, planting was carried out earlier than expected and the crop was formed by July 15. The interphase period between potato planting and seddling emergence decreased, while that from seddling emergence to harvesting increased, consequently, the yield increased by 11.6…14.7%. The maximum yield was obtained with the Red Scarlet variety using the white covering material, the minimum – in the check variant without covering. The same trend is typical for other varieties. It has been established that covering with any material has a positive eff ect on the duration of the potato growing season and the yield by increasing the period of tuberization. Covering allows getting early potato varieties 2 weeks earlier in the Moscow region.


PLoS ONE ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. e0231831 ◽  
Author(s):  
Anna Jama-Rodzeńska ◽  
Amadeusz Walczak ◽  
Katarzyna Adamczewska-Sowińska ◽  
Grzegorz Janik ◽  
Izabela Kłosowicz ◽  
...  

2009 ◽  
Vol 79-82 ◽  
pp. 1767-1770 ◽  
Author(s):  
Shu Ang Han ◽  
Kai Hui Jiang ◽  
Jun Wu Tang

In this paper, 2.5D SiO2f/SiO2 composites were fabricated via sol-gel process employing 2.5D braided silica fiber fabrics as reinforcements and high pure silicasol as slurry. The process parameters are optimized and the optimal parameters are as follows: the silicasol of 30.8 wt. % as slurry, microwave drying, and sintering at 900 °C. Utilizing the optimal process parameters, the density and the flexural strength of the composites can reach 1.65 g•cm-3 and 80.68 MPa respectively. Dielectric properties of the 2.5D SiO2f/SiO2 composites were also measured, and the real part of the permittivity is 3.40 at 5 GHz. The excellent mechanical and dielectric properties of the 2.5D SiO2f/SiO2 composites can well meet the requirements of radome materials.


2015 ◽  
Vol 815 ◽  
pp. 188-192
Author(s):  
Y.S. Lee ◽  
F. Malek ◽  
E.M. Cheng ◽  
Wei Wen Liu ◽  
Kok Yeow You ◽  
...  

This paper is to study the dielectric properties, magnetic properties, and dielectric conductivity of Multi-walled carbon nanotubes (MWCNTs) and polyester (PE) composites. The composites with different amount of MWCNTs (5-15%) have been studied in the Ku-Band range (12.4-18 GHz). The rectangular waveguide (WR-62) was used to measure the dielectric properties and magnetic properties of the samples. The results show the dielectric properties and conductivity of MWCNTs/PE composites is increasing with the MWCNTs filler increases. The real part of dielectric properties values increase from 5.5 to 26.6 with increasing the MWCNTs loading from 5 % to 15 %. The increasing of MWCNTs filler in the MWCNTs/PE composites does not effects on magnetic properties, the real part and imaginary part of magnetic properties are approximate to 1 and 0. The highest conductivity of 15 % MWCNTs loading is reach to 11.02 (S/m) at 18 GHz. Keywords: composites, dielectric properties, magnetic properties, conductivity


2009 ◽  
Vol 16 (2) ◽  
pp. 260-263 ◽  
Author(s):  
B. Andriyevsky ◽  
C. Cobet ◽  
A. Patryn ◽  
N. Esser

Spectra of the real and imaginary parts of the pseudo-dielectric permittivity, 〈∊1〉(E) and 〈∊2〉(E), of ferroelectric ammonium sulfate crystals, (NH4)2SO4, have been measured in the range of electronic excitations 4.0 to 9.5 eV by ellipsometry using synchrotron radiation. Temperature dependences of the corresponding susceptibilities, 〈χ1〉(T) and 〈χ2〉(T), obtained for the photon energy E = 8.5 eV, related to excitations of oxygen p-electrons, reveal sharp peak-like temperature changes near the Curie point T C = 223 K. The large temperature-dependent increase of the imaginary part of the susceptibility χ2(T), together with a simultaneous decrease of the real part of the susceptibility χ1(T), take place at the phase transition. These anomalies have been ascribed mainly to the SO4 group of the crystal structure.


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