کیا کوئی ضابطہ ایسا کسی آئین میں ہے : کہ وہ مجرم ہے جو تہذیب کی تزئین میں ہے
میرے اس عہد میں رسوا جسے ٹھہرایا گیا : اُس کی عظمت کا بیاں سورۃٔ والتّین میں ہے[۱]
پوچھ سکتا ہوں میں اے صاحبِ دستار و عمل : کیوں کمر بستہ تو اقدار کی توہین میں ہے
جو بھی لب وا ہو مرے عہد میں وہ لب سی دو : یہ بھی اک حکم مرے شاہ کے فرامین میں ہے
اژدرِ کذب نے سچائی کو کھا ڈالا ہے : کوئی وقعت کہاں اب تیرے براہین میں ہے
تیری قسمت پہ تڑپ اٹھتا ہوں اے خاکِ وطن : جو مرے عہد کے اب دستِ سلاطین میں ہے
تو نے کیا خود کو سرائیل سمجھ رکھا ہے : کیوں ترا دخل مرے دل کے فلسطین میں ہے
جس قدر آج یہاں اونچی ہوا میں اُڑ لیں : آخری فیصلہ دیوانِ علیّین میں ہے
وقت کو جو لیے پھرتا تھا کبھی مٹھی میں
اب وہ شاکر نہ ہی تیرہ میں ہے نے تین میں ہے
Constructivism is the basis for thinking of a contextual approach, namely that knowledge is built not a set of facts, concepts, or rules that are ready to be remembered. Students must construct that knowledge and give meaning through real experience. Students need to be accustomed to solving problems, finding something useful for themselves, and struggling with ideas. The teacher will not be able to give all knowledge to students. Students must construct knowledge in their own minds. Knowledge is not static, but is constantly evolving and changing as students construct new experiences that force them to base themselves and modify previous knowledge. Learning must be packaged into the process of constructing knowledge rather than receiving knowledge. In the learning process, students build their own knowledge through active involvement in the learning and teaching process. Students become the center of activities, not teachers. Critical thinking is an attempt by someone to check the truth of information using the availability of evidence, logic, and awareness of bias. Critical thinking skills are the cognitive processes of students in analyzing systematically and specifically the problems faced, distinguishing these problems carefully and thoroughly, as well as identifying and reviewing information to plan problem solving strategies.
This thesis has been divided into four chapters. The first chapter is about the introduction of polypyrrole (PPy) and other conducting polymers (CPs). The importance and drawbacks of conducting polymers have been thoroughly discussed followed by the discussion about the need of composites of these polymers. The importance of CPs-metal oxide composites over individual components has been deliberated. The relevant literature and references have also been included. The second chapter is related to the synthesis, characterization and analytical applications of PPy-vanadium penta oxide (V2O5) composites. The materials were synthesized in aqueous medium by chemical oxidation polymerization method using FeCl3.6H2O as an oxidant followed by characterization using Fourier transform infrared (FT-IR) spectroscopy, X-ray diffractometer (XRD), thermogravimetry analyzer (TGA), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) technique, surface area and pore size analyzer, UV-visible spectrophotometry and LCR-meter. PPy was amorphous while the composites were crystalline in nature. The content of V2O5 improved the compactness, thermal stability, surface area and electrical conductivity of the composites. The band gap energy was found to be of the same value for all the composites. The gas sensing properties of the materials were checked for ammonia gas and some other organic liquid vapors. The composite PPy/8%V2O5 was of highest sensitivity and selectivity towards ammonia at room temperature. The limit of detection (LOD, response time and recovery time of this material was 1.4 ppm, 10.5 and 81.6 s, respectively. The performance of this composite has been compared with the reported data. In the third chapter, synthesis, characterization and analytical applications of PPy-MnO2 composites have been elaborated. The composites were synthesized and characterized by the same procedure as mentioned for Chapter-2. The content of MnO2 has almost same x effect on the properties of these composites as in case of PPy/V2O5 composites. However, the band gap energy was found to decrease continuously with increase in the percent amount of MnO2 in the composites. After studying the gas sensing characteristics, the composites PPy/10%MnO2 was found of unique properties with respect to its sensitivity, selectivity and limit of detection towards ammonia gas. The response of this material was far better than the already done work. The LOD was 0.4 ppm with response and recovery time 32.1 and 40 s, respectively. In the fourth chapter, unique PPy/V2O5-MnO2 hybrid composites has been synthesized, characterized and applied as gas sensor by the same methods as discussed for PPy/V2O5 composites. These materials were also applied as gas sensor. The composite PPy/4%V2O5-5%MnO2 (S3) was of better performance as compared to the reported hybrid composites regarding ammonia gas sensitivity. The LOD, response and recovery time of the material at room temperature was 5 ppm, 75 and 76 s, respectively.