Papers by Keyword: Fe

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Authors: X.J. Yu, Zhen Fang, Shan Yong Wang, Yun Yan, Jian Hua Yin
Abstract: An Elastic Plastic-Damage (EPD) model is developed to model the softening behaviour of the cement-soil admixture based on continuous damage mechanics. The softening behaviour is considered to be characteristic outcome of the material degradation due to damage in material. Material degradation is modelled by reducing progressively the stiffness and yield stress of the material when the damage variable has attained a critical index. The basic equations of the model are derived and presented. A Fortran program for this model has been developed and implemented into a finite element code ABAQUS. In order to evaluate the applicability of this model, several unconfined compression tests are simulated using ABAQUS with this model. The computed results are compared with measured data and good agreement is achieved.
Authors: Qing Ye, Hai Ping Wang, Hai Xia Zhao, Shui Yuan Cheng, Tian Fang Kang
Abstract: Cu supported on acid-treated sepiolite catalysts (xCu/H-Sep, x = 0  20.0 wt%) or Cu-Fe mixed supported on acid-treated sepiolite catalysts (yFe-10Cu/H-Sep, y = 0  20.0 wt%) were prepared by the incipient wetness impregnation method. The xCu/H-Sep and yFe-10Cu/H-Sep catalysts were characterized by means of XRD, BET, XRF, XPS, and H2-TPR techniques, and their catalytic activities were evaluated for the SCR of NO with propylene. XPS and XRD results indicate that there was the co-presence of Cu+-Cu2+ and Fe2+-Fe3+ over the surfaces of yFe-10Cu/H-Sep catalysts, and there was a strong interaction between Cu, Fe and sepiolite. High promotional effect of iron additive on the catalytic performance of Cu/H-Sep catalyst were found in C3H6-SCR of NO reaction. The highest activity of 65% NO conversion was obtained over 15Fe-10Cu/H-Sep catalyst at 280 oC under the condition of 1000 ppm NO, 1000 ppm C3H6, and 5% O2. The high catalytic activity of 15Fe-10Cu/H-Sep catalyst for NO reduction was due to its high reducibility to activate C3H6 to selectively reduce NO in the presence of excess O2. The high dispersion of copper oxides and strong metal-support interaction over 15Fe-10Cu/H-Sep catalyst also improve its catalytic performance.
Authors: Zheng Guang Zou, Kai Liu, Yu Fang Shen, Zhi Gang Xiao, Fei Long, Yi Wu
Abstract: This work focus on the effects of C vacancy on wetting of Fe to TiC/Fe at the cermet interfaces. We do the whole work using the first-principles density functional theories. The ideal work of adhesion of the pure interface is not big enough, comparing with the expeimental value. Our calculations suggest that the C vacancy at the interface is a very important factor for interface banding of TiC/Fe cermet composite. An adequate quantities of C vacancies at the interface can improve the wetting of TiC/Fe interfaces.
Authors: Tatiana Yu. Kiseleva, Alla A. Novakova, Tatiana S. Gendler
Abstract: Amorphous shell formation on the Fe-particles surface in course of mechanochemical nanocomposite synthesis in Fe2O3+Fe, Fe2O3+Al+Fe, and Fe2O3+Ga+Fe powders mixtures have been observed by Mössbauer spectroscopy and magnetic measurements.
Authors: Joong S. Jeon, Stefan De Gendt, Srini Raghavan, Marcia Almanza-Workman, Cynthia Gonsalves, Bob Ogle
Authors: Yong Xing Hao, Su Juan Shi, Lv Yun Yang, Song Wei Yang
Abstract: Radial ring rolling is an unsteady plastic deformation process. Internal stress of the ring is foundation of formation of the plastic hinge. The radial wall thickness of ring changes gradually along ring circumferential direction. Theoretical analysis and FE simulation show that: the plastic hinge is not always exactly opposite to the rolling deformation zone in ring rolling process without guide-roll. The plastic hinge position angle β0 is affected by ratio of rolling entrance wall thickness H0 and rate of wall thickness change η. Curve of β0-H0/η is shaped as double U staggered relative to each other. With the H0/η increasing, β0 reduces gradually and approaches to π in the range of H0/η>6.28. H0/η>14.6H0/R2. Only when the rolling process is steady, and H0≈R2, β0 is greater than π, and approximates to π. The β0 fluctuates dramatically when H0/η≈5.71. In some cases, H0/η may fluctuate in 0 to 6.28, leading to the instability of plastic hinge position.
Authors: Shamsuddin Saidatulakmar, Shamsul Baharin Jamaludin, Zuhailawati Hussain, Zainal Arifin Ahmad
Abstract: Fe-Cr matrix composite reinforced with alumina with mean powder sizes of 13, 23, 24 and 64 μm was successfully obtained through powder metallurgy method. The powder mixture were blended at a rotating speed of 250 rpm for thirty minutes and uni-axially pressed at a pressure of 750 MPa. Samples identified as J13, J23, J24 and J64 according to alumina particles size were sintered in a vacuum furnace under 10-2 Torr at a temperature of 1100°C for two hours with 10°C/minutes heating rate. The peaks of XRD patterns have been identified as belonging to the phases of Fe, Cr and alumina. The EDX analysis confirms the existence of Fe, Cr, Al and O. Reinforcing the Fe-Cr matrix with alumina particles bigger than 13 µm deteriorated the microstructure and mechanical properties of the composites. The wear coefficient for sample reinforced with 13 µm alumina particles is 2.46 × 10-11 with compressive strength of 278 MPa. Meanwhile for sample reinforced with 64 µm alumina particles its wear coefficient is 5.09 × 10-11 and compressive strength is 81 MPa. It is found that reinforcing smaller alumina particles sizes to Fe-Cr matrix resulted in better wear and strength properties of the composites.
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