This experimental study investigated the effects of milling conditions on cutting forces and finished surface roughness. The face-milling processes were performed using heat-treated SKD61 steel at a hardness of 46 HRC. With three controllable factors/levels (cutting speed, axial depth of cut, and feed rate), the most suitable orthogonal array L 27 was performed with four performance measurements that are amplitudes of cutting forces in three directions (feed, normal, and axial) and surface roughness. With ANOVA analysis, the effect of cutting conditions on the amplitudes of cutting forces and surface roughness were analysed and modelled. The most suitable regression of the cutting force's amplitudes and surface roughness was a quadratic regression with the confidence level is more than 93.74 %, and they were successfully verified via experimental results with very promising results. The relationship between cutting force and surface roughness was also investigated. Furthermore, using the Taguchi and ANOVA methods, the optimization process of surface roughness was performed with very close results (different of surface roughness about 4.58 %). The approach method of the present study can be applied in industrial machining to improve the surface quality in finish face-milling the SKD61 hard steel.

The authors have no funding to report. Author contributions: Martijn Van Heel and Ba Tuan Vu were involved in the conceptualization of the study. Dung Tien Hoang collected the data. Martijn Van Heel drafted the article and Ba Tuan Vu, Guy Bosmans, Katja Petry, and Karla Van Leeuwen revised the manuscript.

In this study, the efficiency of integration between Taguchi and TOPSIS in multi-response optimization of powder mixed electrical discharge machining (PMEDM) process was evaluated. The input parameters, such as workpiece and tool electrode material, polarity, pulse on time (ton), pulse off time (toff), Current (I) and powder concentration have been selected to optimize two responses; namely surface roughness (Ra) and surface hardness (HV). The results show that titanium powder mixed dielectric fluid improves multi-response optimization efficiency in PMEDM. In addition, machining conditions, such as tool electrode material, powder concentration, pulse on time, polarity, current density, A×G and B×G interactions play a very important role on S/N ratio of C* whereby powder concentration has the strongest influence. TOPSIS-Taguchi is a potential method for multi-response optimization in PMEDM. However, the optimal results using ANOVA analysis show that there is a necessity to have more studies in TOPSIS-Taguchi to improve the integration efficiency between two methods for optimizing multiple responses in PMEDM.

While the role of agricultural land size in rural Vietnam is well established for rural livelihoods, no evidence for the importance of land quality has been provided thus far in the literature. In the current study of the North Central Region of Vietnam, we examine how land quality affects crop income, total income, and poverty using secondary data from a sample of 2,468 households. In particular, we used an instrumental variable method to address the potential endogeneity of land quality. We provide the first evidence that land quality increases local household income and the likelihood of escaping poverty. The finding is robust even after accounting for the endogeneity of land quality and controlling for various important household characteristics. Notably, we show the mechanism by which land quality positively affects income and poverty reduction through its positive effect on crop income. Also, our study reveals that land fragmentation is negatively linked with land quality. This could be explained by the fact that fragmented land receives less investment (e.g., fertilizers or irrigation), resulting in lower land quality. The study offers a useful implication that reducing fragmentation may help local households invest more in land, thereby increasing crop income, which in turn improves their economic well‐being.