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Synthesis and Characterization of Polycrystalline Ferroelectric Bulk Ceramics

Thesis Info

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Author

Sareecha, Nasira

Program

PhD

Institute

The Islamia University of Bahawalpur

City

Bahawalpur

Province

Punjab

Country

Pakistan

Thesis Completing Year

2017

Thesis Completion Status

Completed

Subject

Chemistry

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/13377/1/Nasira_Sareecha_Chemistry_HSR_2017_IUB_Bahawalpur_30.11.2017.docx

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676727461139

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BaTiO3 and PbTiO3 ceramics were prepared through solid state sintering reaction. The studies were attempted at the phase pure and crack free preparation and electrical investigations of BaTiO3 ceramics with Ba/Ti molar ratio (0.98 and 0.94) and PbTiO3 ceramics (1.00, 0.98 and 0.94) Pb/Ti molar ratio in the wide range of temperatures (40–700°C) at 1kHz frequency of the ceramics perhaps for the first time. Studies were attempted to find the understanding of the conduction process and useful implementation of the controlling parameters. Thermogravimetric and Differential scanning calorimetric analysis (TGA-DSC) revealed melting temperatures, weight losses and variations in the enthalpy of crystallization of the as ground powders. Ceramics with all precursor composition were perovskite (ABO3), ferroelectric materials. Cubic structures (Pm-3m) and tetragonal (P4mmm, P4mm, P4MM) crystal structures were indicated. Curie temperature (Tc) increased from120-130°C with decreasing Ba/Ti contents. With Pb and Bi doping, Curie temperature (TC) was shifted from 120 -200°C and 120 -160°C respectively. Pb/Ti contents did shift the Curie temperature. Broad dielectric constant peaks and pronounced dielectric anomalies with relaxor like behavior were observed in the paraelectric regions. Resistivity decreased with increasing temperature, all specimens showed semiconductor behavior with negative temperature coefficient of resistivity (NTCR) characteristics. Mobility of electrons increased with thermal activation due to hopping of charge carriers from one site to another. Ohmic conductivities and associated activation energies were evaluated by impedance spectroscopy. Conductivity followed Arrhenius Law with Ea values lying in the range of single ionized and doubly ionized oxygen vacancies and Pb vacancies; ionic conduction was supposed to be responsible. Well defined hysteresis P-E loops under electric fields showed ferroelectric characteristics.
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مزاجِ وقت دیکھو، وقت کی رفتار کو دیکھو

مزاجِ وقت دیکھو وقت کی رفتار تو دیکھو
لکھا ہے کیا سرِ دیوار تم دیوار تو دیکھو

مقدر میں یہی لکھا تھا یہ بھی ٹھیک ہے لیکن
سبب کچھ اور بھی ہو گا تم اپنی ہار تو دیکھو

اے حاکم تجھ پہ لازم ہے نگہ بانی رعایا کی
کہ اس کی مفلسی اور اس کا حالِ زار تو دیکھو

نہیں تیار خلقت کیوں تمھاری بات سننے کو
خدا کے واسطے اس خلق کا انکار تو دیکھو

اگر وہ باوفا ہوتا ، کبھی ایسا نہیں کرتا
صفِ دشمن میں جا بیٹھا ہے میرا یار تو دیکھو

خدا کا شکر کرتا ہے ادا دردِ محبت پر
ہُوا ہے محوِ سجدہ عشق کا بیمار تو دیکھو

تمھارا نام جپتا ہے فقط تائبؔ تمھارا ہے
تم اس کی چاہ تو دیکھو، تم اس کا پیار تو دیکھو

Contemporary Challenges Regarding Muslim-Christian Dialogue and Its Solution in the Light of Nobel Sīrah of the Holy Prophet ﷺ

Islam recognizes the status and respect of other faiths and communities for socioeconomic and sociopolitical development. Therefore, the kind Messenger of Allah صلى الله عليه وسلمwas the first ever personality in the human history who accepted the identity of other faiths and involved them in state affairs of the city state of Madīnah in 610 CE/1AH. The citizens of the first Islamic State including Jews, Christians and Polytheists were treated as equal and respected citizens. The door of discussion and mutual cooperation were opened for all faiths and communities of the society. For that purpose, the Holy Prophet صلى الله عليه وسلم set out some special parameters and principles of dialogue and interaction with other faiths. These principles may be freedom of religion, mutual respect and cooperation, interfaith tolerance, focus on common issues, active participation in state and social activities etc. The history is eye witness of this conduct that Muslim rulers and public care these principles and promote them in all ages of the Muslim governance. However due to some reason modern era have been observed of not being compatible with minorities in east as well as in the west. Categorically, they are having encounters with many difficulties, challenges and issues for security, rights and peaceful coexistence in all over the world. Unfortunately, Pakistan have also considered to be the part of hyper national and international sociological environment regarding minorities. In order to overcome these issues and challenges then we must follow the Prophet’s Seerahصلى الله عليه وسلم regarding interfaith dialogue and mutual cooperation in a pluralistic society like Pakistan. In this study, the efforts are made to explore contemporary challenges and its solution in light of the Seerah of the Prophet صلى الله عليه وسلمfrom current sociopolitical context.

Effect of Examination Conducted by Punjab Examination Commission on Curriculum at Elementary Level in the Punjab

The purposes of this mixed methods explanatory sequential study were: (1) to investigate effects of examination, conducted by the Punjab Examination Commission for grade VIII, on curriculum and instruction, (2) to identify pressures associated with result of the examination, (3) to explore teachers‟ trust in examination, and (4) to identify uses of result of the examination. Five hundred and twenty six elementary school teachers who taught to grade VIII were randomly selected from seven different districts of the Punjab to complete survey in quantitative part of the study. Survey instrument designed for this study contained 112 closed response Likert scale items. Semi-structured interviews were used to collect data for qualitative phase of the study. Maximum variation strategy of purposive sampling was used to select 28 elementary school teachers for qualitative part of the study. These teachers were chosen from larger sample took part in quantitative phase of the study. The purpose of the qualitative part was to further explore quantitative results. The meta inferences revealed that the examination has not only narrowed curriculum and instruction but learning of the students as well. Teachers were pressurized by school principal and district education authority for good result in the examination. Consequences associated with result of examination influenced teachers to use helping books, old exam papers and practice tests in their classes. Most of the teachers used instructional strategies which were teacher centered and focused on drill and practices of the content likely to appear in examination. Teachers were of the view that the examination was not improving education at elementary level because students attempted MCQs without understanding, no or very limited focus on untested subjects and even selective study within tested subjects. Teachers, irrespective of school location and type, shared that the examination was not credible, lacked fairness, invigilation and marking quality was poor and felt threat to their career because of the viii consequences associated with the result of the examination. It was further explored that teachers and school made very limited use of result of examination. Participants of the study were of the view that the examination was not high in stakes for students but it is for teachers. This study has multiple implications for bringing improvement by consulting teachers who are working in the field and confront with the unintended consequences of educational reforms