Wyniki wyszukiwania - BazTech

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Physical properties of ZnTe semiconductor thin films prepared by high vacuum resistive system

Abbas M., Shah N. A., Jehangir K., Fareed M., Zaidi A.

Materials Science Poland

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2018

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Vol. 36, No. 3

364--369

EN

Zinc telluride (ZnTe) polycrystalline films have been grown on well-cleaned glass substrates by thermal vacuum evaporation technique using 99.99 % pure ZnTe powder as an evaporant. The samples were prepared at different substrate temperatures, rates of evaporation and thicknesses. The X-ray diffraction was used to study the structure of the films. The structures of the samples were found to be polycrystalline with preferred (1 1 1) orientation. Transmission spectra of all ZnTe films were recorded in the range of 300 nm to 2500 nm. The films were electrically characterized using Hall effect measurements at room temperature. It has been stated that the electrical resistivity, mobility and carrier concentration are strongly influenced by the substrate temperature. From the SEM results, it is clear that the surface of ZnTe is very smooth with occasional large particles on it.

2

Solid state friction stir welding using square groove butt joint

Thamizhmanii S., Mohideen R., Mujahid A., Zaidi A., Hasan S.

Journal of Achievements in Materials and Manufacturing Engineering

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2015

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Vol. 73, nr 2

118--123

EN

Purpose: of this paper is to high light the application of Friction Stir Welding (FSW) process using square butt joint. Design/methodology/approach: The design adopted was tool spindle speed, tool plunge depth and transverse movement of the work piece. Findings: The findings are encouraging. It is possible to increase the strength of the joint by 22.45% from the basic tensile strength. The optimum tensile stress obtained was at spindle speed of transverse speed of 700 RPM at transverse speed 325 mm/min taking into consideration the fracture of the materials. The optimum travel speed for the spindle speed 700 RPM is 325 mm/min, this is because the heat generation and the time for the material to joint was increased. But the 200 mm/min is not optimum for the spindle speed 700 rpm because, there is too much heat generation and the welded part become soft by the welding. When there is not enough heat generated, the stir between materials or part will not occur or not properly welded. Research limitations/implications: The limitations in this research were proper fixture. Machine should have variable tool rotation instead of fixed machine spindle speed. Practical implications: It is possible to weld by FSW process and not tested in any application. Originality/value: The research on FSW The limitations in this research were proper fixture. Machine should have variable tool rotation instead of fixed machine spindle speed. is upcoming project and not much work done in this field. Using square shaped joint unique and no references so far using this square groove. Many of the research were by straight butt joint.

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Bayesian reliability models of Weibull systems: State of the art

Zaidi A., Ould Bouamama B., Tagina M.

International Journal of Applied Mathematics and Computer Science

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2012

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Vol. 22, no. 3

585-600

EN

In the reliability modeling field, we sometimes encounter systems with uncertain structures, and the use of fault trees and reliability diagrams is not possible. To overcome this problem, Bayesian approaches offer a considerable efficiency in this context. This paper introduces recent contributions in the field of reliability modeling with the Bayesian network approach. Bayesian reliability models are applied to systems with Weibull distribution of failure. To achieve the formulation of the reliability model, Bayesian estimation of Weibull parameters and the model's goodness-of-fit are evoked. The advantages of this modelling approach are presented in the case of systems with an unknown reliability structure, those with a common cause of failures and redundant ones. Finally, we raise the issue of the use of BNs in the fault diagnosis area.