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Home > Synthesis and Study of Thin Film Composites of Poly Vinyl Alcohol -Silica and Poly Vinyl Alcohol - Alumina

Synthesis and Study of Thin Film Composites of Poly Vinyl Alcohol -Silica and Poly Vinyl Alcohol - Alumina

Thesis Info

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Author

Humayun, Muhammad

Program

PhD

Institute

University of Peshawar

City

Peshawar

Province

KPK

Country

Pakistan

Thesis Completing Year

2010

Thesis Completion Status

Completed

Subject

Chemistry

Language

English

Link

http://prr.hec.gov.pk/jspui/handle/123456789/1210

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676727476291

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Poly (Vinyl Alcohol)-silica and Poly (Vinyl Alcohol)-alumina hybrid materials were synthesized in aqueous medium by the sol-gel method using hydrochloric acid(HCl) as catalyst and silicon ethoxide and aluminum butoxide as silica and alumina precursor respectively. Transparent, flexible thin film composites of homogenous thickness were obtained at room temperature after drying for 5 days. The hybrid composites were characterized by Ultra Violet- Visible (UV-Vis), Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), Energy Dispersive X-rays (EDX), X-Rays Difractometry (XRD), Thermogravimetric/ Differential Thermal analysis (TG/DTA), Thermal Conductivity (TC), mechanical properties and water uptake measurements. SEM micrographs revealed that silica and alumina was dispersed in the PVA matrix without the large aggregation of particles. The PVA-silica or alumina composites offer an outstanding balance of toughness. Tensile results indicate that there is a compromise in properties when compositing silica or alumina with PVA as the addition of silica or alumina makes the material stronger and more useful. This is related to an increased modulus and decreased elongation at break with increasing silica or alumina content. FTIR spectroscopy failed to identify any perturbation because of blending of silica or alumina with PVA, but only specific interaction of the hydrogen bonding between different groups of PVA and alumina/silica was observed. The comparison of UV-Vis spectroscopic analysis, of PVA, PVA - silica and PVA- alumina composite films showed almost similar spectrum except that peak of 335 nm shown in pure PVA shifted towards lower wavelength with both silica and alumina. This change in peak position is due to the interacting particles of silica or alumina. This change may be attributed to aggregation of silica /alumina particles. Between the silica and alumina, silica is causing more effect on this peak while alumina is to a lesser extent, which we think is due to bigger size of silica molecules. XRD pattern of pure PVA and PVA- silica or alumina composite point out the wide bulge among 16 and 22 of 2-θ degree, and this is connected to amorphous field in Poly (Vinyl Alcohol) thin film polymer. It was discovered that the extent of crystalline domain of composite Poly (Vinyl Alcohol) has improved with addition of silica or alumina. The crystalline movement is amplified with segment wise shift of Poly (Vinyl Alcohol) mass among sites of coordination and relaxation of confined structure raise the crystallinity with increase of silica or alumina. Thermal Conductivity (TC) of PVA composites showed decrease in initial stage until the amount of silicon ethoxide and aluminum butoxide was small (up to 20% silicon ethoxide and 10% aluminum butoxide). However, beyond 20% for silicon ethoxide and 10% for aluminum butoxide the Thermal Conductivity (TC) showed increase. This means that there is a threshold value for Thermal Conductivity (TC) depending upon the added filler. Up to this value, decrease is shown while beyond this there is increase. The TGA curve of the PVA composites showed that there is the thermal stability of the PVA film up to 370 K (97 oC). There was a mass drop from 370 K to 500 K, which may be due to evaporation of surface and structure water. The further drop of weight between 500 K and 738 K is attributed to decomposition and combustion of PVA film. In the temperature range of 738 K to 820 K, a weight loss was due to the transformation from carbon black to carbon dioxide. The whole process is supported by DTA curves. Water uptake swelling index measurements were done which shows the hydrophilic nature of PVA- alumina and hydrophobic nature of PVA- silica. It can be concluded that we have successfully prepared thin Film of PVA-silica and PVA- alumina, which are thermally stable and with good strength.
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مولاناسید محمد ہاشم ندوی

مولانا سید محمد ہاشم ندوی
ہمارے لیے تیسرا حادثہ مولانا سید محمد ہاشم ندوی کی وفات کا ہے، وہ ندوہ کے لائق فرزند تھے، جس سال راقم ندوہ میں داخل ہوا ہے ، اسی سال وہ فارغ ہوئے تھے اور حضرت سید صاحب کی سفارش سے اسی زمانہ میں دائرۃ المعارف حیدرآباد میں ملازم ہوگئے تھے، جس سے ریٹائر ہونے تک وابستہ رہے، وہ اس کے اہم رکن تھے، بہت سے کتابیں ان کے اہتمام میں شائع ہوئیں، بعض کی انہوں نے تصحیح بھی کی اور بعض پر مقدمے لکھے، انہوں نے ایک مفید علمی خدمت یہ انجام دی کہ دنیا کے مختلف کتب خانوں میں عربی کی جو اہم اور نادر و نایاب کتابیں ہیں ان کی فن وار فہرست ’’تذکرۃ النوادر‘‘ کے نام سے مرتب کی جو دائرۃ المعارف سے شائع ہوگئی ہے، ملازمت سے سبکدوش ہونے کے بعد حیدرآباد ہی میں متوطن ہوگئے تھے، ان کی صحت عرصہ سے خراب تھی، گذشتہ مہینہ حیدرآباد کے ایک خط سے معلوم ہوا کہ ان کا انتقال ہوگیا، ستر سے کچھ اوپر عمر رہی ہوگی۔ اﷲ تعالیٰ اس خادم علم کی اپنی رحمت و مغفرت سے سرفراز فرمائے۔
(شاہ معین الدین ندوی، جولائی ۱۹۷۱ء)

 

Factors Affecting Human Rights in Khyber Pakhtunkhwa, Pakistan

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Relationship Between Instructional Leadership and Teachers’ Job Performance in Secondary Schools in the Province of Khyber Pakhtunkhwa, Pakistan

Title: “RELATIONSHIP BETWEEN INSTRUCTIONAL LEADERSHIP AND TEACHERS’ JOB PERFORMANCE IN SECONDARY SCHOOLS IN THE PROVINCE OF KHYBER PAKHTUNKHWA, PAKISTAN”. Researcher: Zafar Khan Supervisor: Dr. Umar Ali khan University: Gomal University, Dera Ismail Khan, KPK, Pakistan Year: 2012 Subject Area: Education Degree: PhD This study aimed at exploring teachers’ perceptions of instructional leadership of secondary school heads and relationship of these perceptions with their performance on the job at secondary school level in the province of Khyber Pakhtunkhwa (Pakistan).The population of study consisted of 4488 teachers working in secondary schools during academic year 2009-10. Six hundred and fifty secondary school teachers were selected by using stratified random sampling technique, 493 (309 male and 184 female) teachers from 14 districts of the province responded with a response rate of 76%. Two instruments were used to collect the data: Instructional leadership questionnaire (ILQ) and teacher job performance scale (TJPS). ILQ was developed by the researcher and reliability of ILQ was measured by using Cronbach alpha coefficient, resulting in 0.87 for formulating educational objectives, 0.85 for developing learning environment, 0.83 for protecting instructional time, 0.87 for supervising and monitoring the progress, 0.88 for promoting professional development, and 0.96 for the whole questionnaire. Teacher Job Performance Scale (TJPS), developed by Hanif (2004) was adapted for this study. Mean, Standard xdeviation, t-test, Correlation and regression were the statistical techniques used for the analysis of data.The results showed that teachers perceived instructional leadership of their school heads at moderate level in four functions, except for the function of providing learning environment that was perceived by teachers at higher level. Gender wise results showed that female secondary school heads were perceived better instructional leaders than their male counterparts in formulating educational objectives, providing learning environment, supervising and monitoring the progress, but in the functions of protecting instructional time and promoting professional development both are at the same level. No statistical significant difference was found in the teachers’ perception about instructional leadership of secondary school heads in rural and urban areas.A positive and statistical significant correlation at moderate level was found between Teachers’ perceptions of instructional leadership with their job performance. There were 16 out of 20 pairs showed positive correlations between Perceived instructional leadership measures and teachers’ job performance at .05 levels of significance. Positive impact of perceived instructional leadership was found on teacher job performance. According to teachers’ perceptions, 37% estimate in their job is contributed by the instructional leadership of school heads. As the perceptions of teachers about instructional leadership increases their level of performance also increases. It was concluded that instructional leadership employed by secondary school heads is at moderate level and contribution of instructional leadership function promoting professional development in the promotion of teachers’ job performance is higher as compared to other four functions. Research study suggested that secondary school heads should pay more attention on supervision and monitoring of the instructional process in their schools. xiIt is further recommended to Elemenatry and Secondary Education Department that workshops seminars and conferences should be organized so that school heads’ and teachers come together to discuss their problems for bringing improvement in teaching learning. This study provided a foundation for further research and added a measurement tool to the leadership literature.