As contemporary emerging materials, fiber-reinforced plastics/polymers (FRP) are widely used in aerospace automotive industries and in other fields due to their high strength-to-weight ratio, high stiffness-to-weight ratio, high corrosion resistance, low thermal expansion and other properties. Drilling is the most frequently used process in industrial operation for polymer composite laminates, owing to the need for joining structures. However, it is a great challenge for operators to drill holes in FRP materials, due to the non-homogenous and anisotropic properties of fibers. Various damages, such as delamination, hole shrinkage, and burr and tool wear, occur due to the heterogeneous and anisotropic nature of composite laminates. Therefore, in this study, carbon fiber reinforced polymer (CFRP)/aramid fiber reinforced polymer (AFRP) hybrid composites (C-AFRP) were successfully synthesized, and their drilling characteristics, including burr generation and tool wear, were also mainly investigated. The drilling characteristics of CFRP and C-AFRP were compared and analyzed for the first time under the same operating conditions (cutting tool, spindle speed, feed rate). The experimental results demonstrated that C-AFRP had higher tensile strength and good drilling characteristics (low thrust and less tool wear) compared with CFRP. As a lightweight and high-strength structural material, C-AFRP hybrid composites have great potential applications in the automobile and aerospace industries after the slight processing of burrs generated during drilling.

As a high oxygenated fuel, bioethanol has already obtained more and more widespread attention in diesel engines. The present work aims to study and compare effects of various diesel-bioethanol-biodiesel ternary mixture fuels on combustion and emissions from a four-cylinder diesel engine. A series of engine experiments are conducted on neat diesel fuel (D100), 95% D100 blended with 5% bioethanol and 1% biodiesel by volume (D95E5B1), 90% D100 blended with 10% bioethanol and 1% biodiesel by volume (D90E10B1), and 85% D100 blended with 15% bioethanol and 1% biodiesel by volume (D85E15B1) according to various engine loads (40, 80 and 120 Nm). The experimental results show that the peak value of pressure and heat release rate (HRR) in the cylinder, nitrogen oxides (NOx) and smoke emissions increase with the increase in engine load, but the brake specific fuel consumption (BSFC) decreases. There is no significant variation in cylinder pressure with the addition of ethanol, but HRR is improved and NOx and smoke emissions are effectively controlled. It is exciting that the addition of ethanol can simultaneously reduce NOx and smoke emissions under medium and high load conditions. Specifically, at 120 Nm, ethanol addition simultaneously reduces NOx emissions by 2.08% and smoke opacity by 36.08% on average. Through the results of this study, it is found that the ethanol can improve the combustion of the four-cylinder diesel engine and also effectively control the emissions of NOx and smoke. Therefore, ethanol will play an important role in the future research field of energy saving and emission reduction for diesel engines.

Ceramics are advanced engineering materials in which have been broadly used in numerous industries due to their superior mechanical and physical properties. For application, the industries require that the ceramic products have high-quality surface finishes, high dimensional accuracy, and clean surfaces to prevent and minimize thermal contact, adhesion, friction, and wear. Ceramics have been classified as difficult-to-machine materials owing to their high hardness, and brittleness. Thus, it is extremely difficult to process them with conventional finishing processes. In this review, trends in the development of non-conventional finishing processes for the surface finishing of difficult-to-machine ceramics are discussed and compared to better comprehend the key finishing capabilities and limitations of each process on improvements in terms of surface roughness. In addition, the future direction of non-conventional finishing processes is introduced. This review will be helpful to many researchers and academicians for carrying out additional research related to the surface finishing techniques of ceramics for applications in various fields.

At present, the preparation cost of biodiesel is still higher than that of diesel. Thus, directly using vegetable oil before transesterification can greatly reduce the cost. This study investigated the application characteristics of the direct use of crude palm oil (CPO) in a common rail direct injection (CRDI) diesel engine. In this study, the combustion characteristics, engine performance, and emission characteristics of the CRDI diesel engine operated with CPO0 (neat diesel fuel), CPO10 (10% CPO blended with 90% diesel fuel by volume), CPO30 (30% CPO blended with 70% diesel fuel by volume), and CPO50 (50% CPO blended with 50% diesel fuel by volume) at three idling speeds (750 rpm, 1500 rpm, and 2250 rpm) were evaluated. The results obtained from the experiment elucidate that combustion starts earlier by increasing the idling speed. The addition of CPO to diesel fuel resulted in a decrease in the peak in-cylinder pressure at all idle speeds and a decrease in the maximum heat release rate (HRRmax) at 750 and 1500 rpm, but an increase in HRRmax at 2250 rpm. On the other hand, increasing idle speed is beneficial for reducing carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx), but it increases smoke emissions. In addition, adding 10% and 30% CPO to diesel fuel can reduce both HC, NOx, and smoke emissions simultaneously.

In this paper, we propose a new ultra-high-precision magnetic abrasive finishing method for wire material which is considered to be difficult with the existing finishing process. The processing method uses a rotating magnetic field system with unbonded magnetic abrasive type. It is believed that this process can efficiently perform the ultra-high-precision finishing for producing a smooth surface finish and removing a diameter of wire material. For such a processing improvement, the following parameters are considered; rotational speed of rotating magnetic field, vibration frequency of wire material, and unbonded magnetic abrasive grain size. In order to evaluate the performance of the new finishing process for the wire material, the American Iron and Steel Institute (AISI) 1085 steel wire was used as the wire workpiece. The experimental results showed that the original surface roughness of AISI 1085 steel wire was enhanced from 0.25 µm to 0.02 µm for 60 s at 800 rpm of rotational speed. Also, the performance of the removed diameter was excellent. As the result, a new ultra-high-precision magnetic abrasive finishing using a rotating magnetic field with unbonded magnetic abrasive type could be successfully adopted for improving the surface roughness and removing the diameter of AISI 1085 steel wire material.