Effects of crystallinity and electron mean-free-path on dielectric strength of low density polyethylene

Author(s):  
Y. Tanaka ◽  
N. Ohnuma ◽  
K. Katsunami ◽  
Y. Ohki
Author(s):  
Ahmed Jassim Mohammed, Riad Manadi Ramadan, Raed Muslim Shab

In this research, Calculation the Attenuation of X-ray radiation for low density polyethylene composites with oyster shells powder (extracted from the Caspian Sea in Iran), low density polyethylene production in the form of powder by the State Company for Petrochemical Industries (Basra-Iraq), the range of the added of oyster shells powder (extracted from the Caspian sea in Iran) has the values (0%, 2.5%, 5%, 10%, 15%, 20%, and 25%) for low density polyethylene weight and the added oyster shells powder with the particular size (≤ 250 μm). were investigated through several variables, such as, linear attenuation coefficient(μ) and mean free path(λ). The obtained results were appeared that the added oyster to reduce the spaces between the polymer chains, which reflects the high ability of the polymer as (10%-20%), and this increase will give further property that increase the attenuation x-ray of the prepared specimens. Where the practical study and the beam of intensity of energy (30 kv) and)VG.M = 600 voit(. The results showed that when increasing filler content, the total linear attenuation coefficient increases while the mean free path decreases. The mean free path (λ) at (2.5%) is (2.1 cm (, while at (20%) is (0.40 cm). The value of the linear attenuation coefficient (μ) at (20%) is)2.44 cm-1(, while at (2.5%) is) 0.49 cm-1(.


2017 ◽  
Vol 50 (1) ◽  
pp. 36-57 ◽  
Author(s):  
Nurul Hidayah ◽  
Mariatti Mustapha ◽  
Hanafi Ismail ◽  
Mohamad Kamarol

This study determines the applicability of nanofillers (silica, boron nitride, and zinc oxide) in linear low-density polyethylene (LLDPE)/silicone rubber (SR) insulation compounds. Design of experiment is adopted to model the relationship between the properties (permittivity, loss tangent, dielectric strength, and volume resistivity) and factors (SR content, type of nanofiller, and nanofiller loading) for performance optimization. It is observed that SR content and type of nanofiller significantly influence the electrical properties of LLDPE/SR nanocomposites. Nanofiller loading, however, causes a small variation in the properties of the nanocomposites except for dielectric strength. From the optimization, it is found that the optimum formulation composition is 10 wt% of SR and 2 vol% of nanoboron nitride.


2000 ◽  
Author(s):  
Taofang Zeng ◽  
Gang Chen

Abstract When electrons sweep through a double-heterojunction structure, there exist thermionic effects at the junctions and thermoelectric effects in the film. While both thermoelectric and thermionic effects have been studied for refrigeration and power generation applications separately, their interplay in heterostructures is not understood. This paper establishes a unified model including both thermionic and thermoelectric processes based on the Boltzmann transport equation for electrons, and the nonequilibrium interaction between electrons and phonons. Approximate solutions are obtained, leading to the electron temperature and Fermi level distributions inside heterostructures and discontinuities at the interfaces as a consequence of the highly nonequilibrium transport when the film thickness is much smaller than the electron mean free path. It is found that when the film thickness is smaller than the mean free path of electrons, the transport of electrons is controlled by thermionic emission. The coexistence of thermoelectric and thermionic effects may increase the power factor when the electron mean free path is comparable to the film thickness.


2004 ◽  
Vol 566-568 ◽  
pp. 532-537 ◽  
Author(s):  
N. Barrett ◽  
E.E. Krasovskii ◽  
J.-M. Themlin ◽  
V.N. Strocov

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