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Home > Processing, Characterization, Structure and Ionic Conductivity of Disordered Pyrochlores, Ho2 Zryti1-Y 2O7 Holmium Zirconium-Titanate, Hzt

Processing, Characterization, Structure and Ionic Conductivity of Disordered Pyrochlores, Ho2 Zryti1-Y 2O7 Holmium Zirconium-Titanate, Hzt

Thesis Info

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External Link

Author

Shafique, Muhammad

Program

PhD

Institute

University of Peshawar

City

Peshawar

Province

KPK

Country

Pakistan

Thesis Completing Year

2008

Thesis Completion Status

Completed

Subject

Physics

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/8131/1/Muhammad_Shafique_Physics_2017_UoP_Peshawar_22.06.2017.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676727018064

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In this study, a number of compounds in the Ho2(ZryTi1-y)2O7 pyrochlore system, which undergoes an order-disorder structural transition from pyrochlore to a defect-fluorite type, were investigated. The materials were processed by mechanical milling, followed by a two-step sintering route. The structure was analyzed via Rietveld refinements using neutron powder diffraction (NPD) data, and further supported by X-ray diffraction (XRD) to identify the phases and determine the composition of the pyrochlore-fluorite transformation boundary at room temperature. The NPD refinement and XRD results show that compositions with 0.0 ≤ y ≤ 0.5 crystallized into a pyrochlore structure while the ones with 0.7 ≤ y ≤ 1.0 crystallized into the defect-fluorite structure. The composition with y=0.6 was found to be a two phase (pyrochlore and defect-fluorite) mixture. Neutron refinement results confirmed that the cation disorder was independent of the anion Frenkel disorder and also the degree of Frenkel disorder O(1)-O(3) was different from the O(2)-O(3) anion disorder. The relation between x-parameter and anion Frenkel disorder was found to be linear for the pyrochlore structure. Unit-cell parameters were obtained using Rietveld refinements for the whole series and were also calculated via the Nelson-Riley function. The ionic conductivity studies were undertaken via AC impedance analysis to determine the electronic behaviour and its relationship to the structural change in the available temperature range of 300–700°C. The trends in ionic conductivity and activation energy were explained on the basis of NPD and XRD data. The composition at the pyrochlore-fluorite boundary exhibited the lowest activation energy and highest ionic conductivity.
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76. Al-Insan/The Human Being

76. Al-Insan/The Human Being

I/We begin by the Blessed Name of Allah

The Immensely Merciful to all, The Infinitely Compassionate to everyone.

76:01
a. Was there not a time in the past when the human being was nothing even to be mentioned?!

76:02
a. Indeed, it is WE WHO created human being of a drop of the mingling of seminal and
ovarian fluid of male and female, so that WE may test him during his lifetime.
b. Then WE enabled him with hearing and seeing and intellect.

76:03
a. And WE guided him on to the Right Path
b. to see whether he be grateful by following the Right Path, or be ungrateful by straying off the Right Path.

76:04
a. WE have definitely prepared for the ungrateful - by being sinful - chains and shackles and
a blazing fire.

76:05
a. As for the grateful - by being righteous - they will drink from cups containing a mixture of camphor/musk -

76:06
a. from a spring at which the servants of Allah will drink,
b. - making it gush out abundantly.

76:07
a. The righteous are the ones who used to fulfill their vows, and
b. stand in awe of the Time the evil of which will be encompassing everyone.

76:08
a. And they - the righteous – used to give food
- to the needy, for the love of HIM,
- and also to the orphan,
- and to the captive/prisoner of war,

700 Surah 76 * Al-Insan

76:09
a. saying within themselves:
b. ‘We feed you only for the Face...

افغانستان کی اسلامی تاریخ کے پیش رو صحابہ کرام: عہد خلافت عمر بن الخطاب رضی اللہ عنہ

The era of caliphate was the golden era of Islam. In this era the boundaries of Islamic state spread far and wide. From the caliphate of Abubakkar saddique (RA) Islamic conquest had started. At that time the Muslim armies reached Syria and Byzentine. But the first arrival of sahaba in Afghanistan was in the caliphate of Hazrat Umar (RA). The torchbearer of Islam came here for the preaching of Islam and to lead these people and turn their lives according to Quran and Sunnah. Before the advent of  Islam Afghanistan was the centre of Buddhist and other several faiths. Through the efforts of these companions of Muhammad (S.A.W) Islam got spread through the mountains and deserts of Afghanistan and all the Pathan tribes enter in the holy deen. In the following lines we will discuss thier efforts and journeys towards Afghanistan.

Prevalence of Low Bone Mineral Density Amongst Resident Doctors at the Aga Khan University Hospital, Nairobi

Objective: This was a cross-sectional study carried out amongst resident doctors training at the Aga Khan University Hospital, Nairobi to determine their bone mineral density and investigate for any association between the bone mineral density and the residents’ lifestyle. Methods: 65 randomly selected residents from various departments in the Aga Khan University Hospital, Nairobi, underwent a Dual Energy X-ray Absorptiometry (DXA) scan and filled out questionnaires to assess their physical activity, sunlight exposure and calcium intake. This was carried out between April and June 2011. Results: 65 residents were included in the final analysis. 50 residents (76.9% with a 95% CI = 65% – 85%) were found to have a low bone mineral density while 15 (23.1%) were normal. No significant association was found between the various residents’ lifestyle factors and their bone mineral density. Logistic regression analysis showed an association between increasing age and low BMD (p value = 0.038). Conclusion: There is a 76.9% prevalence of low bone mineral density amongst residents at the Aga Khan University, Nairobi which was thought to be spurious due to reference database used in the BMD analysis. Attempts should be made in coming up with a local reference normative database for use in comparison of bone mineral density in the country.