In this work, the effects of temperature, acid concentration, and mechanical activation on dissolution of ilmenite were studied using the statistical design of experiment technique. Mechanical activation was carried out using a planetary ball mill in dry mode, and the resulting structural changes were characterized by the particle size analysis, specific surface area measurements, and X-ray diffraction method. The results obtained indicated that intensive milling led to a significant decrease in the ilmenite particle size and that after 20 minutes, particles tended to agglomerate. However, after 90 minutes, the BET specific surface area increased to 9. 36 m2/g. In addition to surface changes, mechanical activation led to intense changes and disorders in the crystal structure of ilmenite as amorphization degree increased to 94. 30% and the volume weighted crystallite size and lattice strain changed from 346 nm and 0. 13% to 14 nm and 1. 44%, respectively. The results of the dissolution tests in the form of experimental design indicated that a suitable model could fit the experimental data in 95% confidence level. The coefficient factors for acid concentration, mechanical activation, and temperature were 3. 75%, 33. 04%, and 9%, respectively. Mechanical activation had the highest effect on titanium extraction in comparison to the other factors involved. Also in addition to its dominant effect on ilmenite dissolution, it also weakened the temperature effect. However, the results of the kinetic tests proved that mechanical activation led to promotion of the temperature effect on increasing the dissolution reaction rate in the initial stages. Finally, a dissolution yield of more than 98% was achieved through 90 minutes of activation at 95° C and 55 wt. % acid concentration.

This study deals with the processing, microstructure, and sintering behavior of TiC-reinforced NiFe matrix composites, containing 5, 10, 20 and 30 wt.% TiC. Mechanical alloying and powder technology were used to successfully fabricate the composite. The characteristics of the milled powders and the consolidated specimens were examined using scanning electron microscopy and X-ray diffraction method. The microstructural study revealed that the TiC particles were distributed uniformly in the NiFe matrix phase. The composite hardness also increased with TiC content.

Background: Effective protocols are introduced for par thenogenesis activation in oocytes. Hydrostatic pressure can act as a mechanical stimulator that rearranges egg contents, leading to new structural or molecular combination.Alternatively, mechanical stimulation could stimulate a mechanically-gated process, such as opening or closing of stretch activated ion channels. This study, investigated the use of hydrostatic pressure in the activation of parthenogenesis in mouse oocytes matured in vitro.Materials and Methods: Immature oocytes were isolated from 8-week-old female NMRI mice. Oocytes were cultured in a- MEM culture medium containing 7.5 IU HCG under mineral oil for 24 hours. In vitro -matured oocytes with a polar body were subjected to 10 mmHg pressure for 10, 20, 30 minutes (treatments I, II and III).Oocytes without exposure to pressure were considered as control. Oocytes from two groups were culture for 72 hours and embryo development rate was assessed.Results: After 72 hours, cleavage rate in treatments I, II, III and control was 18.27%, 41.92%, 24.72% and 6.44% respectively.The result showed that, oocyte activation rate in all treatments was higher than control (p<0.05).The highest cleavage rate associated with treatment II which was significantly different from treatmentsI, III and control (p<0.05).Conclusion: We inferred that the exposures to hydrostatic pressure in the parthenogenetic activation can improve the development of in vitro matured oocytes.

In this research, the effect of mechanical activation on phase transformation of monoclinic zirconia was investigated. It was revealed that the transformation of monoclinic to tetragonal at a temperature as high as 1250° C is very slow. Milling of pure zirconia with monoclinic structure facilitates this phase transformation. The XRD patterns of the milled samples show that after 4 hrs tetragonal peaks are appeared and after 48 hrs phase transformation is completed. The kinetics of this transformation was also studied and the corresponding correlation was proposed. Cubic structure could also been obtained after 150 hrs milling. The sharp increase of the pressure and temperature at the collision points of the balls are the main reasons for this phase transformation at the ambient overall temperature.

In the present work, the effect of aluminum on mechanical activation of hematite graphite- aluminum mixture has been investigated. Various amounts of aluminum powder (0 to 10 wt%) was added to hematite-graphite mixture (C/O=1 or 18.40 wt% graphite). Then, the mixture was mechanically treated by means of ball milling within different time periods, from 0 to 10 hours. XRD and SEM tests were carried out to study the effect of aluminum and milling time on activation mechanism of the mixture. It was found that existence of aluminum particles, as formable material, in the brittle hematite-graphite mixture could influence on the microscopic condition and subsequently on the behavior and intensity of mechanical activation of the mixture.

Calcium phosphate bioceramics especially hydroxyapatite (HA) are the main mineralogical part of bone and tooth that have the great biocompatibility with hard tissue. In this research, nanostructure hydroxyapatite synthesized by mechanical activation procedure with precursors concluded of calcium and phosphor. Phase development, structure, particle size and morphology of HA were investigated by X-ray diffraction pattern analysis (XRD), Fourier transform infrared spectroscopy (FTIR), zetasizer instrument, scanning electron microscopy (SEM). XRD results confirmed the formation of hydroxyapatite phase and present of major bonds of HA approved by FTIR. Presence of two particle size distribution picks in zetasizer curve presented that a part of powder was agglomerated and SEM images have shown this agglomeration. The results showed the minimum time of hydroxyapatite is 20 hours that formed the mean particle size of HA  » 157 nm and crystallite size » 27 nm. The crystallite size and crystallinity of powders decreased to 24 nm and 98% to 33.6 %, respectively.

The growing demand for lithium-ion batteries has prompted significant research into enhancing the performance and stability of cathode materials. This study investigates the effects of high-energy ball milling on the properties of niobium dopped LiNi0.8Co0.1Mn0.1O2 (NMC811) cathode materials. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS) were utilized to characterize the synthesized materials. Electrochemical performance was assessed through galvanostatic charge-discharge tests. In an un-milled NMC811 sample with Nb doping, the average primary particle size was 207 nm. Nb doping combined with ball milling further reduced the primary particle size to 150 nm. However, the use of ball milling, in addition to the excessive cationic mixing caused by Nb doping, negatively affected the rate capability probably due to the increased Nb content in the Li layer. The initial discharge capacity of NMC811 for the un-milled and ball milled samples was 161.9 and 140.6 mAh g-1 at 0.1C, respectively. After 100 cycles at 0.5 C, the capacity retention for the un-milled and milled samples were 66.2 and 89.8%, respectively within the voltage range of 2.8-4.3 V. This improvement in capacity retention is attributed to the reduced particle size and enhanced structural stability, which together help maintain better performance over extended cycling.