Optimization of the technology of cutting heavy-gage sheet metal by thermal method

The analysis of the influence of various technological solutions used in the thermal cutting of heavy-gage sheet metals to reduce the deformations of the resulting piece parts is given. It has been suggested to use a gas-oxygen cutting technology with packing sequence without localization of heat build-up. The effect of improving the efficiency and quality of production using the developed cutting technology is shown.

Influence of Carbon Black/Silica Hybrid Ratio on Properties of Passenger Car Tire Sidewall

Influence of carbon black (CB)/precipitated silica (SiO2) hybrid ratio on properties of a passenger car tire (PCT) sidewall based on natural rubber (NR) and butadiene rubber (BR) blend was investigated. Rubbers filled with various hybrid filler ratios at a constant loading of 50 phr were prepared and tested. The filler reinforcement efficiency in association with crucial properties of the tire sidewall were of interest. Results show the enhanced rubber–filler interaction with increasing SiO2 fraction leading to the improvement in many vulcanizate properties including hardness, tensile strength, tear strength and fatigue resistance, at the expense of cure efficiency and hysteretic behaviors (i.e., reduced heat build-up resistance and increased dynamic set). The results also suggest the improvement in tire sidewall performance of the NR/BR vulcanizates reinforced with CB/SiO2 hybrid filler, compared to that of the CB-filled vulcanizate.

Mechanical properties and dissipation energy of carbon black/rubber composites

The effects of carbon black on the properties of rubber composites were studied in order to explore their value in producing low rolling resistance truck tires. Carbon black with different grades, N330 (coarser grade of 26–30 nm) and N220 (finer grade of 20–25 nm), was used as a reinforcing agent of natural rubber. The effects of different ratios of carbon black N330 at 40, 45, 50 and 55 parts per hundred rubber (phr) and N220 at 30, 35, 40 and 50 phr were investigated. Rubber composites with N220 had greater rubber/carbon black interaction than those with N330. The Mooney viscosity of rubber composite increased when the carbon black ratio increased. After vulcanisation of rubber, the samples were characterised by dynamic mechanical analysis, tensile strength and heat build-up. The results showed that the strength of rubber composites increased with increasing carbon black ratios. Interestingly, at the same bound rubber level, rubber composites with N220 presented lower dissipation energy, heat build-up and better mechanical properties than those with N330. This study indicated that reinforcement with an optimum amount of carbon black N220 would improve several desirable characteristics of rubber composites when used in low rolling resistance truck tires.

Dodecanol and KH-592 Co-Modify Silica to Prepare Low Heat Build-Up and High Performance Natural Rubber Composites

Friction between filler/filler and filler/matrix in rubber composites is the main factor affecting the heat build-up. In this study, we used dodecanol and silane coupling agent KH-592 to co-modify silica to prepare silica/natural rubber (NR) composites. When dodecanol and KH-592 are grafted onto the surface of silica at the same time, dodecanol can also shield part of the hydroxyl groups by its molecular chain length, which further improves the dispersibility of silica particles. The silane coupling agent KH-592 can form a bridge structure between the silica and the NR matrix under the action of a mercapto group, and improve the interaction between the filler and the matrix. By controlling the use ratio of dodecanol and KH-592, the dispersion of the filler and the interaction between the filler and the matrix can be adjusted. Thereby, the friction between the filler/filler and the filler/matrix is reduced, and a low heat build-up rubber composite material is prepared. Through co-modification, we prepared a series of low-heat build-up silica/NR composites, where the minimum heat generation reached 13∘C. The co-modified silica/NR composite material not only meets the requirements of green tires, but also has low heat build-up characteristics, providing a new strategy for preparing green and energy-saving tires.

Experimental investigation on the influence of carbon-based nanoparticle coating on the heat transfer characteristics of the microprocessor

In the current scenario, thermal management plays a vital role in electronic system design. The temperature of the electronic components should not exceed manufacturer-specified temperature levels in order to maintain safe operating range and service life. The reduction in heat build-up will certainly enhance the component life and reliability of the system. The aim of this research work is to analyze the effect of multi-walled carbon nanotube and graphene coating on the heat transfer capacity of a microprocessor used in personal computers. The performance of coating materials was investigated at three different usages of central processing unit. Multi-walled carbon nanotube-coated and graphene-coated microprocessors showed better enhancement in heat transfer as compared with uncoated microprocessors. Maximum decrease in heat build-up of 7 and 9℃ was achieved for multi-walled carbon nanotube-coated and graphene-coated microprocessors compared to pure substrate. From the results, graphene has been proven to be a suitable candidate for effective heat transfer compared to with multi-walled carbon nanotubes due to high thermal conductivity characteristics of the former compared to the latter.