Fabrication of Nickel Nanostructure Arrays Via a Modified Nanosphere Lithography

In this paper, we present a modified nanosphere lithographic scheme that is based on the self-assembly and electroforming techniques. The scheme was demonstrated to fabricate a nickel template of ordered nanobowl arrays together with a nickel nanostructure array-patterned glass substrate. The hemispherical nanobowls exhibit uniform sizes and smooth interior surfaces, and the shallow nanobowls with a flat bottom on the glass substrate are interconnected as a net structure with uniform thickness. A multiphysics model based on the level set method (LSM) was built up to understand this fabricating process by tracking the interface between the growing nickel and the electrolyte. The fabricated nickel nanobowl template can be used as a mold of long lifetime in soft lithography due to the high strength of nickel. The nanostructure–patterned glass substrate can be used in optical and magnetic devices due to their shape effects. This fabrication scheme can also be extended to a wide range of metals and alloys

Single phase grid connected current source inverter: Mitigation of oscillating power effect on the grid current

Although voltage source inverters (VSIs) are the most common DC-AC grid-tied converters, current source inverters (CSIs) are considered to be promising candidate, thanks to their low THD voltages/currents and inherent short-circuit proof. The natural oscillating power at the DC-link creates the main CSI's single phase application challenge. Hardware based solutions to this problem exhibits additional cost, components and size. Traditional software based solutions detect the oscillating power effect from a second harmonic component in the DC-link current; hence modify the carrier signal to mitigate the oscillation effect on the grid current. Those solutions are characterised mainly by excessive computational burden in addition to poor tracking. In this paper, a Proportional Resonant (PR) controller, tuned at the third harmonic, is utilized to minimize the oscillating power effect from the grid side, and hence acts as a harmonic cancellator (HC). The proposed technique features: (i) simple implementation, (ii) easy tuning, and (iii) superior steadystate elimination. In addition to simulation, experimental setup is implemented to validate the proposed technique effectiveness.Qatar National Research FundScopu

An enhanced performance IPT based battery charger for electric vehicles application

World-wide scientists/engineers were motivated to research in the area of renewable energy resources and to reduce the consumption of fossil fuels. Hence, electric and hybrid vehicles have won the attention of many researchers and vehicles manufacturers. Electric vehicle requires a charging system having a high degree of reliability and robustness and to run maintenance-free. This brings the inductive power transfer (IPT) systems to play a significant role in electric vehicle battery chargers applications. IPT system has proved its capability to be a safe, convenient, and efficient electric vehicle battery charger through its features, such as operating in a harsh environment, high efficiency at reasonable power levels, and decreasing equipment maintenance through operating without any mechanical contacts. This paper presents an enhanced performance IPT system, which is particularly suitable for electric vehicle battery charging application. The proposed system is slightly affected by the small tolerance between sender (track coil) and receiver (pickup coil). Relation between application, transformer configuration selection, and power converter controller is discussed in details. The proposed system effectiveness is investigated, in addition to simulation, by an experimental set-up.Qatar National Research FundScopu

The effect of osteoporosis and diabetes mellitus on serum magnesium level of Sudanese ladies

Background: Osteoporosis is an important physiological change in elderly post-menopause ladies. It can induce a lot of complications such as hip fracture. Similar to serum calcium and phosphorus, serum magnesium is decreased in the osteoporosis women. Objective: In this study, evaluation of serum magnesium levels among diabetic osteoporosis-risk Sudanese pre-menopause ladies comparing to control group was carried. Materials: A total of 100 female, 50 low risk control subjects and 50 osteoporosis-risk female (25 with uncomplicated diabetes mellitus and 25 with other risks) were included in this study. Methods: Serum magnesium estimation was performed by AAS method. Results: There was no significant difference in serum Mg level between control group (0.90 mmol/L) and osteoporosis-risk (0.89mmol/L) groups (p > 0.05) while a significant differences were presented between control group (0.87mmol/L) and osteoporosis-risk ladies in diabetic (0.93 mmol/L) groups (p < 0.05) in this study. Conclusion: The serum magnesium level cannot be used as osteoporosis marker for pre-menopausal ladies