scholarly journals Study on the Preparation of High-Temperature Resistant and Electrically Insulating h-BN Coating in Ethanol Solution by Electrophoretic Deposition

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 871
Author(s):  
Kun Jia ◽  
Xu Meng ◽  
Wei Wang
Keyword(s):  
High Temperature ◽  
Electrophoretic Deposition ◽  
Adhesive Strength ◽  
Performance Test ◽  
Breakdown Strength ◽  
Hexagonal Boron Nitride ◽  
Ceramic Powder ◽  
Ethanol Solution ◽  
Experimental Conditions ◽  
Good Adhesive

A hexagonal boron nitride (h-BN) coating of micron thickness is deposited directly on 316L stainless steel (SS316L) cathode through efficient, adjustable electrophoretic deposition (EPD) in a suspension system containing surfactant and ethanol. It is based on the mixing of h-BN with polyethyleneimine (PEI) resulting in positively charged ceramic powder making cathodic electrophoretic deposition possible. The thickness of the resulting h-BN coatings deposited on SS316L could be controlled by varying the time and the voltage of electrophoretic deposition. The deposition kinetics and mechanism have been discussed. After soaking in Al(H2PO4)3 solution and high-temperature annealing, the h-BN coatings exhibited good adhesive strength. Furthermore, a novel method has been used for the evaluation of the adhesive strength to explore the appropriate experimental conditions. X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were employed to characterize the h-BN coatings. The h-BN coatings are applied for the DC breakdown performance test and exhibit remarkable breakdown voltage and breakdown strength.

scholarly journals Effect of the Process Parameters on the Adhesive Strength of Dissimilar Polymers Obtained by Multicomponent Injection Molding

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1039 ◽  
Author(s):  
Luciano Pisanu ◽  
Leonardo Costa Santiago ◽  
Josiane Dantas Viana Barbosa ◽  
Valter Estevão Beal ◽  
Marcio Luis Ferreira Nascimento
Keyword(s):  
Adhesive Strength ◽  
Natural Fiber ◽  
Fiber Composite ◽  
Pure Shear ◽  
Central Area ◽  
Dissimilar Materials ◽  
Type I ◽  
Coconut Fiber ◽  
Adhesive Properties ◽  
Experimental Conditions

The growing demand in the consumer market for products with sustainable technologies has motivated new applications using overmolded natural fiber composites. Therefore, studies have been conducted mainly to understand the adhesive properties of overmolded parts. In the present study, a polypropylene (PP) composite with 30% coconut fibers without additives was developed with the aid of a corotating twin screw extruder. Subsequently, a multicomponent injection mold was developed based on the geometry of the ISO 527 type I specimen, in which samples overmolded with PP and PP–coconut-fiber composite, with the overlap in the central area, were obtained to evaluate the adhesive strength of dissimilar materials. The objective of this study was to evaluate the bond between PP and PP–coconut-fiber composite under different processing conditions using an adhesive strength testing device to perform a pure shear analysis. The experimental conditions followed a statistical design considering four factors in two levels and a significance level of 5%. The results indicated that adhesive strength increased significantly as the overlap area increased. It was observed that temperature and injection flow rate were the factors that most contributed to strengthening the bonds of dissimilar materials.

scholarly journals Temperature Dependence of Mechanical, Electrical Properties and Crystal Structure of Polyethylene Blends for Cable Insulation

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1922 ◽  
Author(s):  
Lunzhi Li ◽  
Lisheng Zhong ◽  
Kai Zhang ◽  
Jinghui Gao ◽  
Man Xu
Keyword(s):  
High Temperature ◽  
Electrical Properties ◽  
Temperature Dependence ◽  
Elevated Temperatures ◽  
Breakdown Strength ◽  
Temperature Stability ◽  
Xrd Analysis ◽  
Insulation Material ◽  
Cable Insulation ◽  
Polyethylene Blends

There is a long-standing puzzle concerning whether polyethylene blends are a suitable substitution for cable-insulation-used crosslinking polyethylene (XLPE) especially at elevated temperatures. In this paper, we investigate temperature dependence of mechanical, electrical properties of blends with 70 wt % linear low density polyethylene (LLDPE) and 30 wt % high density polyethylene (HDPE) (abbreviated as 70 L-30 H). Our results show that the dielectric loss of 70 L-30 H is about an order of magnitude lower than XLPE, and the AC breakdown strength is 22% higher than XLPE at 90 °C. Moreover, the dynamic mechanical thermal analysis (DMA) measurement and hot set tests suggest that the blends shows optimal mechanical properties especially at high temperature with considerable temperature stability. Further scanning electron microscope (SEM) observation and X-ray diffraction (XRD) analysis uncover the reason for the excellent high temperature performance and temperature stability, which can be ascribed to the uniform fine-spherulite structure in 70 L-30 H blends with high crystallinity sustaining at high temperature. Therefore, our findings may enable the potential application of the blends as cable insulation material with higher thermal-endurance ability.

Effect of pinealectomy on the testicular response of the freshwater snake Natrix piscator to different environmental factors

1989 ◽  
Vol 67 (10) ◽  
pp. 2352-2357 ◽  
Author(s):  
C. Haldar ◽  
R. Pandey
Keyword(s):  
High Temperature ◽  
Pineal Gland ◽  
High Humidity ◽  
Testicular Function ◽  
Experimental Conditions ◽  
Gland Weight ◽  
Tropical Water ◽  
Water Snake ◽  
Temperature Regimes ◽  
Testicular Weight

The effects of different humidity, photoperiod, and temperature regimes on the testicular function of the tropical water snake Natrix piscator were investigated in both sham-operated and pinealectomized snakes. Moderate humidity (50 ± 5%) had no effect on the testis, but high humidity (85 ± 5%) increased the testicular weight and activity of sham-operated snakes after 3, 6, and 9 weeks. Exposures to 14L:10D or 24L:0D and high temperature (42 ± 2 °C) inhibited testicular weight and activity in sham-operated snakes, whereas exposure to 10L:14D or 0L:24D and a low temperature (20 ± 2 °C) had no effect. Pinealectomized snakes did not respond to any of these experimental conditions, but their testicular weight remained the same as that of the pinealectomized controls under natural environmental conditions. The pineal gland showed an opposite response to that of the testes. Pineal gland weight decreased under high humidity and increased under 14L:10D, 24L:0D, and high temperature. These findings suggest that the ecofactors humidity, photoperiod, and temperature play a role in the regulation of testicular function in this snake, and that the pineal gland is implicated in the mediation of these factors.

scholarly journals EXPERIMENTAL ANALYSIS OF THE COMBUSTION CHAMBER COATED WITH Mo AND Al2O3-TiO2 IN A DIESEL ENGINE

2021 ◽  
Vol 55 (4) ◽  
Author(s):  
Murugan Kuppusamy ◽  
Thirumalai Ramanathan ◽  
Udhayakumar Krishnavel ◽  
Seenivasan Murugesan
Keyword(s):  
Combustion Chamber ◽  
Fuel Consumption ◽  
Thermal Efficiency ◽  
Performance Test ◽  
Ceramic Powder ◽  
Specific Fuel Consumption ◽  
Emission Characteristic ◽  
Powder Materials ◽  
Brake Specific Fuel Consumption ◽  
Brake Thermal Efficiency

The effect of thermal-barrier coatings (TBCs) reduces fuel consumption, effectively improving the engine efficiency. This research focused on a TBC with a thickness of 300 µm insulating the combustion chamber of a direct ignition (DI) engine. The piston crown, inlet and exhaust-valve head were coated using air-plasma-spray coating. Ceramic powder materials such as molybdenum (Mo) and aluminum oxide titanium dioxide (Al2O3-TiO2) were used. A performance test of the engine with the coated combustion chamber was carried out to investigate the brake power, brake thermal efficiency, volumetric efficiency, brake specific fuel consumption and air-fuel ratio. Also, an emission-characteristic test was carried out to investigate the emissions of unburned hydrocarbon (HC), carbon monoxide (CO), nitrogen oxides (NO, NO2, NO3) and smoke opacity (SO). The results reveal that the brake thermal efficiency and brake specific fuel consumption show significant increases because of these coating materials. The effect of the Al2O3-TiO2 coating significantly reduces the HC and CO engine emissions.

Design of High Temperature and High Pressure Petroleum Bullets Performance Test Device

2012 ◽  
Vol 580 ◽  
pp. 346-349
Author(s):  
Xiao Qing Li ◽  
Ren Qiang Liu ◽  
Da Zhong Hua ◽  
Xiao Yan Liu
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
High Temperature ◽  
Performance Test ◽  
Convection Heat Transfer ◽  
Local Area ◽  
Temperature Fields ◽  
Test Time ◽  
Test Device ◽  
High Pressure Reaction

A high temperature and high pressure reaction autoclave for petroleum bullets performance test is designed in this paper. Heat transfer in both vertical and horizontal reaction autoclave structure is analyzed and calculated. Considering system heat loss, heating power of these two kinds of devices is calculated in different test time. Meanwhile, temperature fields in these two kinds of autoclave are simulated. According to the comparison result, the authors come to the conclusion that temperature field in vertical reaction autoclave is uniform and can meet design demand with a temperature difference less than ±5°C. Horizontal reaction autoclave in which there are small eddies in air interlayer cannot meet demand because eddies enhance the convection heat transfer in local area. Based on this conclusion, a reasonable reaction autoclave structure can be designed.

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