Prospect and status of iron-based rare-earth-free permanent magnetic materials

Li, Da,Li, Yong,Pan, Desheng,Zhang, Zhidong,Choi, Chul-Jin Elsevier 2019 Journal of magnetism and magnetic materials Vol.469 No.-

<P><B>Abstract</B></P> <P>With the advent of high performance permanent magnets based on the rare-earth (RE) elements such as Sm-Co, Nd-Fe-B alloys in 1980s, the application areas have been extended from the electronics to hybrid electric vehicles and wind turbines etc. However, the advantages of these RE based magnets may be overshadowed by the supply constraints, high prices and environmental issues. Much attention has been paid on non-RE element based permanent magnetic materials as next generation of permanent magnetic materials, due to low cost, large coercivity and high Curie temperatures (working temperatures). A variety of methods are available to manufacture RE-free permanent magnetic materials in bulk, nanostructure, nanocomposite and thin films. The proper scale-up methods to produce magnetic nanostructures with high energy efficiency have still been a significant challenge, which are very important to the development of novel RE-free permanent magnetic materials to meet tomorrow’s energy needs. In this review paper, we emphasize to introduce the prospect and status of developments of iron-based RE-free hard-magnetic nanomaterials involving magnetic thin films, nanocomposites and nanostructures.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Several fundamental physics effects of magnetic theory are introduced for high permanent magnetic properties. </LI> <LI> The research progress of Fe-based rare-earth-free hard-magnetic materials is reviewed. </LI> <LI> The magnetic properties and preparation method of Fe-based hard-magnetic nanomaterials are summarized. </LI> </UL> </P>

Numerical study on supercavitating flow in free stream with regular waves

Li, Da,Lyu, Xujian The Society of Naval Architects of Korea 2020 International Journal of Naval Architecture and Oc Vol.12 No.1

In this study, the supercavitating flow of a high-velocity moving body near air-water surface is calculated and analyzed based on a commercial CFD software ANSYS Fluent. The effect of regular wave parameters including both wave height and wavelength on the cavitating flow and force characteristics of a body at different velocities is investigated. It is found that the cavity shape, lift coefficient and drag coefficient of the body vary periodically with wave fluctuation, and the variation period is basically consistent with wave period. When the wavelength is much greater than the cavity length, the effect of wave on supercavitation is the alternating effect of axial compression and radial compression. However, when the wavelength varies around the cavity length, the cavity often crosses two adjacent troughs and is compressed periodically by the two wave troughs. With the variation of wavelength, the average area of cavity shows a different trend with the change of wave height.

Numerical study on supercavitating flow in free stream with regular waves

Li, Da,Lyu, Xujian The Society of Naval Architects of Korea 2020 International Journal of Naval Architecture and Oc Vol.12 No.-

In this study, the supercavitating flow of a high-velocity moving body near air-water surface is calculated and analyzed based on a commercial CFD software ANSYS Fluent. The effect of regular wave parameters including both wave height and wavelength on the cavitating flow and force characteristics of a body at different velocities is investigated. It is found that the cavity shape, lift coefficient and drag coefficient of the body vary periodically with wave fluctuation, and the variation period is basically consistent with wave period. When the wavelength is much greater than the cavity length, the effect of wave on supercavitation is the alternating effect of axial compression and radial compression. However, when the wavelength varies around the cavity length, the cavity often crosses two adjacent troughs and is compressed periodically by the two wave troughs. With the variation of wavelength, the average area of cavity shows a different trend with the change of wave height.

Investigation by Simulation of X-ray Beams Produced via Interactions of Suitable Quasi-monoenergetic Electrons with Solid Targets

Lida Nikzad,Alireza Ehtesami-Sarabi 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.65 No.1

X-ray generation by interactions of quasi-monoenergetic electrons with solid lead targets is studied. Various electron energy spectra generated by a laser-plasma accelerator are employed to generateBremsstrahlung and characteristic X-rays. These X-ray photons are simulated by using theMonte Carlo N-Particle Transport Code (MCNP). The present work is mainly focused on exploringthe influence of two parameters of the electron profile, the peak energy (Ep) and the pulse width(E), on X-ray generation. If an electron source with higher Ep and smaller E is used, the efficiencyof X-ray creation is found to be increased in thick targets. However, in thin samples, theelectron profile with lower Ep and larger E dominates.

Young Cambodian Consumers’ Perceptions of Corporate Social Responsibility : Applications of Collectivism, Saving Face, and Buddhism

Lida Meng,Soo-Yeon Kim 한국언론학회 2020 Asian Communication Research Vol.17 No.3

This study explored young Cambodian consumers’ awareness levels and perceptions of CSR, along with their cultural values. A survey of 294 young Cambodian consumers revealed that a majority of them were not aware of the concept of CSR; however, they showed a positive perception of CSR. An application of Visser’s (2008) CSR model for developing countries indicates that respondents placed the greatest importance on the philanthropic dimension, followed by the legal, ethical, and economic dimensions. The results suggest that collectivism is a dominant cultural value influencing perception of CSR in Cambodia. This study is meaningful in that it reveals young Cambodian consumers’ positive perceptions of CSR and provides direction for future studies and practices regarding Cambodian CSR.

Effect of carbon nano tube (CNT) particles in magnetic abrasive finishing of Mg alloy bars

Lida Heng,양균의,Rui Wang,김민수,문상돈 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.12

The Magnetic abrasive finishing (MAF) process is a surface finishing technique in which a magnetic field is used to controlabrasive particles during surface finishing of a material. Because smooth surfaces are required for general use, the magnetic abrasivefinishing process was developed for finishing surfaces. We studied the effect of CNT particles on the surface roughness of aworkpiece. Magnesium alloy bars were used as the cylindrical workpiece and were finished using an MAF process at high workpiecerevolution speeds of 1000, 5000, 10000 and 25000 rpm; diamond pastes with diameters of 0.5, 1, and 3 μm were used forcomparison. The best value for surface roughness was equivalent to treatment at 0.02 μm when 0.01 g of CNT particles wasmixed together with the unbonded magnetic abrasive at 25000 rpm for 20 seconds. CNT particles were applied to the finishingprocess to improve the surface roughness of the material, because they have many advantageous properties such as very highstrength, light weight, elasticity, and high thermal and air stability. CNT particles are particularly effective for the improvement ofMg alloy bar surface roughness in the MAF process.

Shear lag coefficient of angles with bolted connections including equal and different legs through finite element method

Lida Shahbazi,Sepideh Rahimi,Mohamad Hoseinzadeh,Ramzan Rezaieaan 국제구조공학회 2022 Structural Engineering and Mechanics, An Int'l Jou Vol.81 No.4

Shear lag phenomenon has long been considered in numerous structural codes; however, the AISC provisions have now no longer proposed any unique equation to calculate the shear lag ratio in bolted connections for angles in general. It is noticeable that, however, codes used in this case are largely conservative and need to be amended. A parametric study consisting of 27 angle sections with equal legs and different with bolted connections was performed to investigate the effects of shear lag on the ultimate tensile capacity of angle members. The main parameters were: steel grade, connection length and eccentricity from the center of the plate, as well as the number of rows of bolts parallel to the applied force. The test results were compared with the predictions of the classical 1-x/l law proposed by Mons and Chesen to investigate its application to quantify the effect of shear lag. A parametric study was performed using valid FE models that cover a wide range of parameters. Finally, based on the numerical results, design considerations were proposed to quantify the effect of shear lag on the ultimate tensile capacity of the tensile members.

Investigating chip morphology and its characteristics in the high-speed milling of a Ti-6Al-4V thin plate

Lida Zhu,Jijiang Wu,Zhaobin Li,Changfu Liu 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.10

Titanium alloy thin-plates have been widely used in the aerospace, automotive and biomedical industries, to name a few. The chipmorphologies and material properties of the thin plate were investigated under different cutting parameters in this paper. First, to furtherunderstand the variability and inherent rules of chip morphology, the characteristics of multi-surface chips (free, back, and cross-sectionsurfaces) were observed and studied by using a scanning electron microscope. The sawtooth frequency and degree of segmentation wereanalyzed through the geometrical characteristics of a serrated chip. Second, variations in the chip microhardness and the wear of the millcutter were measured and investigated under different machining parameters. Results show that the hardenability increases with the increasein cutting speed and the shear band shows higher microhardness than in other parts. In addition, the degree of insert wear decreaseswith proper cutting speed and feed. Some key conclusions and future work about high-speed milling thin-plate Ti-6Al-4V aregiven.

The effect of exercise therapy, dry needling, and nonfunctional electrical stimulation on radicular pain: a case report

Lida Hosseini,Ardalan Shariat,Maryam Selk Ghaffari,Roshanak Honarpishe,Joshua A. Cleland 한국운동재활학회 2018 JER Vol.14 No.5

Optimal design and performance analyses of the glycerol ether production process using a reactive distillation column

Lida Simasatitkul,Punjawat Kaewwisetkul,Wisitsree Wiyaratn,Suttichai Assabumrungrat,Amornchai Arpornwichanop 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.43 No.-

The use of glycerol from biodiesel industries to produce high value-added products would increase thecompetitive potential of biodiesel producers. The present work investigates the production of glycerolethers, a diesel and biodiesel additive. A single reactive distillation is proposed to overcome the lowglycerol conversion and product yield that limit a conventional process. The theoretical performance ofthe reactive distillation is analyzed taking glycerol conversion and the glycerol ether yield intoconsideration. The simulation results show that the glycerol and mono-tert-butyl ether of glycerol arecompletely used in the reactive stages and thus, the recycle section by which glycerol and the mono-tertbutylether of glycerol are recovered is unessential. The parametric analysis for the reactive distillation isreported. Based on the process economic analysis from a total annual cost, the optimal reactivedistillation configuration for glycerol ether production consists of two rectifying stages, eight reactivestages and one stripping stage.