Showing 4 results for Khanjani
M.j. Khanjani, G.a. Barani, M.r, Rahmanian and M. Sajedi,
Volume 18, Issue 2 (7-1999)
Abstract
G. A. Barani, M. J. Khanjani and J. Ahmad- Auli,
Volume 20, Issue 2 (4-2001)
Abstract
In recent years, installation of plates in canal beds have been considered for sedimentation control and bed load reduction at canal intake. These planes, called submerged vanes, are different in dimensions. They are installed at intakes in-group with reasonable distance from each other. Presence of these vanes at intakes initiate transverse shear stress on river bed and causes sediment transport in the transverse direction. Investigation of flow and sediment transport equations, along with different experiments on physical models, have resulted in a suitable range of sizes and distances for vane installation. But, the determination of optimum sizes and distances for vane installation so as to minimize sedimentation requires the use of optimization techniques.
In this study, the hydrodynamic and optimization models of the vane system are first introduced. As the flow and sediment transport governing equations at intakes was nonlinear, the feasible direction method is used. Optimum size of vanes, distances between them at longitudinal and transverse directions, and the angle of flow inclination have also been determined. The optimum quantities of vane parameters were used to calculate the river bed profile at intakes by Wang et. al. [1] procedure. Comparison of the obtained results with Wang el. al. [1] recommendations confirms the advantage of vanes instalation at optimum conditions to control sedimentation.
Keywords: Submerged Vanes, Feasible Direction, Intake and Sedimentation
A. Khanjani, A. Ghasemi, M. Hadi,
Volume 35, Issue 1 (Journal of Advanced Materials-Spring 2016)
Abstract
In the present research NdFeB thin films coupled with buffer and capping layer of W were formed on Si/SiO2 substrate by means of RF magnetron sputtering. The system was annealed at vaccum at different temperatures of 450, 500, 550,. 600 and 650 °C Phase analysis was carried out by XRD and it was found that NdFeB was formed without the formation of any kind of secondary phase. The cross sectional and grain size of the thin films were measured by scanning electron microscopy. Morphological studies were performed by atomic force microscopy. Magnetic properties of thin films including coercivity, saturation of magnetization and hysteresis area were evcaluated by vibrating sample magnetometer. It was found that by annealing at 400 °C the amorphous layer was formed.The highest intensity of peaks was formed at 550 °C and with an increase in temperature the intensity was declined. The grain size was increased by temperature and had an impact on the coercivity. With an increase of temperature up to 600 °C, perpendicular coercivity was increased and then by further increase of temperatute, coercivity was reduced. Based on the obtained data the temperature of 600 °C was selected as the optimum annealing temperature for reaching enhanced structural and magnetic feature.
A. R. Khanjani, A. Ghasemi,
Volume 35, Issue 2 (Journal of Advanced Materials-Summer 2016)
Abstract
In this study, nine Nd-Fe-B and FeCe thin films with 10-50 nanometers width were prepared by RF magnetron sputtering on the Si/SiO2 substrate. Then, the films were annealed at 800 oC for 5 sec in rapid thermal annealing furnace. X-ray diffractometry (XRD) was used to analyze the phase composition of layers and existance of Nd2F14 and Fe65Co35 phase was confirmed, without formation of any other secondary phase. The layers surfaces were investigated using Field Emission Scanning Electron Microscope (FESEM). The morphology of layers surfaces was investigated using Atomic Force Microscope (AFM). The magnetic properties of layers were evaluated by vibrating sample magnetometer with maximum applied field of 24kOe, in order to measure coercivity, saturation of magnetization, hysteresis area, rectangular ratio and (BH)max. It was found that all layers have vertical magnetic anisotropy. Increasing thickness of FeCo resulted in increasing saturation of magnetization, coercivity and saturation magnetization. The results indicate that by an increase in thickness of FeCo up to 20nm, exchange interaction strength between hard and soft magnetic layers is enhanced and, consequently, maximum energy induced from this hetero-structure is increased.
