doi:10.30723/ijp.v12i23.341

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Publication Date

Mon Feb 18 2019

Journal Name

Iraqi Journal Of Physics

Volume

12

Issue Number

23

DOI

10.30723/ijp.v12i23.341

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Enhancement of gas response of annealed ZnO film for hydrogen gas detection

RF-sputtering

Zinc oxide

Gas sensor

Oxygen-vacancy model.

Thamir A.A.

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The mechanism of hydrogen (H₂) gas sensor in the range of 50-200 ppm of RF-sputtered annealed zinc oxide (ZnO) and without annealing was studied. The X-ray Diffraction( XRD) results showed that the Zn metal was completely converted to ZnO with a polycrystalline structure. The I–V characteristics of the device (PT/ZnO/Pt) measured at room temperature before and after annealing at 450 ^oC for4h, from which a linear relationship has been observed. The sensors had a maximum response to H₂ at 350 ^oC for annealing ZnO and showed stable behavior for detecting H₂ gases in the range of 50 to 200 ppm. The annealed film exhibited higher response than the film without annealing.. The sensing mechanism was modeled according to the oxygen–vacancy model.

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Publication Date

Tue Oct 20 2020

Journal Name

Ibn Al-haitham Journal For Pure And Applied Sciences

Comparison Among Three Estimation Methods to Estimate Cascade Reliability Model (2+1) Based On Inverted Exponential Distribution

inverted exponential distribution

Maximum Likelihood method

Uniformly Minimum Variance Unbiased method

Single Stage Shrinkage Estimator

Mean Squared Error and Cascade Reliability Model (2 1)

Sairan

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In this paper, we are mainly concerned with estimating cascade reliability model (2+1) based on inverted exponential distribution and comparing among the estimation methods that are used . The maximum likelihood estimator and uniformly minimum variance unbiased estimators are used to get of the strengths and the stress ;k=1,2,3 respectively then, by using the unbiased estimators, we propose Preliminary test single stage shrinkage (PTSSS) estimator when a prior knowledge is available for the scale parameter as initial value due past experiences . The Mean Squared Error [MSE] for the proposed estimator is derived to compare among the methods. Numerical results about conduct of the considered

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Publication Date

Tue Oct 01 2013

Journal Name

Journal Of Economics And Administrative Sciences

أثـر الأدوات الداخلية لحوكمة الشركة على رأس المال الـعـامـل وانعكاسهما علـى القيـمـة الاقتصـادية المضـافـة: دراســة تطبيقيـة علـى عينــة مـــن الشـركــات الصنــاعــيــة المـدرجــة في بورصــة عـمّــان لــلأوراق المـالـيـة

/ Corporate Governance Instrument- Net Working Capital- Economic Value Added- Weighted Average Cost of Capital- Capital Asset Pricing Model

أدوات حوكمة الشركات- صافي راس المال العامل- القيمة الاقتصادية المضافة- المتوسط الموزون لكلفة راس المال- نموذج تسعير الاصول الرأسمالية.

ارشد فؤاد

احمد فارس

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Abstract

Objective of this research focused on testing the impact of internal corporate governance instruments in the management of working capital and the reflection of each of them on the Firm performance. For this purpose, four main hypotheses was formulated, the first, pointed out its results to a significant effect for each of corporate major shareholders ownership and Board of Directors size on the net working capital and their association with a positive relation. The second, explained a significant effect of net working capital on the economic value added, and their link inverse relationship, while the third, explored a significant effect for each of the corporate major shareholders ownershi

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Publication Date

Mon Nov 01 2010

Journal Name

Al-nahrain Journal Of Science

Chemical Elements Diffusion in the Solar Interior

The standard solar model and equation of state have been used to study relative diffusion of Hydrogen and Helium in the present time for solar interior

as a function of distance and depth from the center of the star. The effects of temperature and density on diffusion velocity for these chemical elements have been explaned. It is found that heat flow which is arising from these reactions leads to an increase in helium diffusion velocity

while the temperature and density leading to a decrease in Hydrogen diffusion velocity. This means that Hydrogen behaves inversely with that for helium does through these reactions. Accordingly

diffusion percentages for Hydrogen

Helium and other Heavy Elements could be determined for the main sequence stars and white dwarf stars.

H.

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