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Template Assisted Synthesis of Carbonized Polymer Nanowires

Thesis Info

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Author

Siddiqui, Sumaira Masood

Program

PhD

Institute

Pakistan Institute of Engineering and Applied Sciences

City

Islamabad

Province

Islamabad

Country

Pakistan

Thesis Completing Year

2015

Thesis Completion Status

Completed

Subject

Applied Sciences

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/6799/1/Sumaira_Masood_Siddiqui_Nanomaterials_Engineering_2015_PIEAS_14.06.206.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676727563156

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Nanomaterials synthesis is a highly focused area now-a-days due to great significance of nanomaterials in terms of their vast applications including nano-sensors, nano-catalysts, nano-electro-mechanical systems (NEMS) and memory devices etc. One of the facile and low cost techniques to synthesize nanomaterials is the use of templates. A template acts like a scaffold to restrict the in-filtered material and produces nano-scopic replica of it. Since the synthesis takes place in the confined nanospaces, hence high surface area nanostructures can be achieved. By using this type of synthetic strategy, nanostructures can be tailored according to the prescribed requirement through the control of the design of templates. The present thesis presents the work on the synthesis of carbonized polymer nanowires through template mediated technique using different carbon precursors including poly (vinyl) alcohol (PVA), poly (vinyl) chloride (PVC) and chitosan. For synthesis of carbon nanowires, from poly(vinyl) alcohol, carbonization was performed at temperatures of 300°C, 400°C, 500°C, 600°C, 700°C ,800°C and 900°C in the absence of any catalyst. Scanning electron microscopy (SEM) revealed the diameter of the nanowires in the range of 90-120 nm. Detailed characterization using SEM, thermal gravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy and Raman spectroscopy was done confirming the formation of nano-wires and graphitization of amorphous carbon resulting from the PVA pitch. The nanowires formed at temperatures of up to about 600oC were rigid, while those formed at 700oC were quite flexible. At 800oC and 900oC, the nanowires formed were again rigid but of shorter length due to fragmentation of the wires produced. It could be due to the formation of graphitic clusters / crystallites. The work was further extended to develop carbon nanostructures through the PVC thermolysis by infilteration of the synthetic polymer into the nano-pores of the templates. Successful formation of carbon nanowires was realized at 100oC, 200oC, 2 300oC, 400oC, 500°C and 600oC in inert atmosphere. The synthesized nanostructures were characterized for the similar techniques as in the case of PVA. Initiation of aromatization was detected at temperatures as low as 100oC. Up to 200oC, nanofibers were formed. Pure graphitic regions were identified at higher temperatures and SEM showed the formation of nano-tubular structure at 300oC and 400oC. Further increase in temperature up to 600oC caused shrinkage in the diameter of nanotubes resulting in nanowires formation. Apart from using synthetic polymers as carbon precursors, a natural polymer chitosan was also used. It was first irradiated to reduce its molecular weight. Low molecular weight facilitated the infiltration of the polymer into the nano-spaces of the template. Pyrolysis was done at 100°C, 250°C, 300°C, 400°C, 500°C and 600°C. The nanotubes developed at 250°C mainly consisted of the saccharide structure. Drastic increase in weight loss at 300°C collapsed the saccharide structure and extensive aromatization took place as indicated by FTIR spectroscopy. The formation of carbon nanotubes was obvious as demonstrated by Raman spectroscopy and SEM results.
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تعارف

سیدابوالاعلیٰ مودودیؒ ۲۵ ستمبر ۱۹۰۳ء کوحیدرآباد کے شہر اورنگ آباد ( محلی چپلی پورہ) میں پیداہوئے۔ آباؤاجداد کاوطن دہلی تھا ۔لیکن والد حیدرآباد دکن چلے آئے۔[[1]] آپ کاشجرہ نسب سلسلہ چشتیہ سے ملتا ہے۔ آپؒ ننھیال کی طرف سے ترکی الاصل ہیں ۔ددھیال کی طرف سے خواجہ قطب الدین مودودی چشتی کے نام سے منسوب ہوکر مودودی کہلائے ۔اس سلسلے سے ان کانام امام حسین ؓ تک جاپہنچتا ہے ۔آپؒ کی والدہ ماجدہ خواجہ ابومحمدچشتی کی ہمشیرہ اورخواجہ ابواحمد ابدال چشتیؒ کی دختر نیک اختر تھیں ۔[[2]]

مولانا مودودیؒ کے آباؤ اجداد نے نویں صدی میں ہجرت کی اورہندوستان آئے۔ پہلے پہل کرنال کے قریب قصبہ براس میں مقیم ہوئے ،یہ زمانہ سکندر لودھی کاتھا۔وہاں سے مغل بادشاہ شاہ عالم کے زمانے میں دہلی چلے گئے ۔ ان کےخاندان نے خاندان مغلوں کی خدمت کی اورخاص طورپر آخری مغل تاجدار بہادر شاہ ظفر کے دربارمیں بھی رسائی حاصل کی ۔ جنگ آزادی ۱۸۵۷ء کے نتیجہ کے طورپر سلطنت مغلیہ کے زوال کے ساتھ ہی مودودی کے خاندان کی حیثیت کوبھی شدید نقصان پہنچا۔[[3]]

مولانا مودودیؒ کے والدسید احمدحسن تھے جوپیشہ کے اعتبارسے وکیل تھے۔ چونکہ مذہبی گھرانے سے تعلق تھا اس لئے انھوں نے وکالت کاپیشہ ترک کردیا کہ یہ ان کے خیال میں جائز پیشہ نہ تھا ۔مولانا مودودی تیرہ برس کے تھے تووالد پرفالج کاحملہ ہوا اوروہ ۴سال بعد ۱۹۲۰ء میں وفات پاگئے ۔[[4]]



[[1]]         اردو انسائیکلوپیڈیا ، فیروزسنز ،لاہور، ۱۸۹۴ء، ص ۹۶۰

[[2]]          سلیم منصور، خالدجمیل احمدرانا ،تذکرہ سیدمودودی ،ادارہ معارف اسلامی ، لاہور ،۲۰۰۵ء، ص۷۔

DIGITAL LITERACY AS A FOUNDATION FOR RELIGIOUS MODERATION LEARNING AT SALATIGA'S AL-HIJRAH TINGKIR ISLAMIC BOARDING SCHOOL

The current millennial generation, includes santri, who have digital literacy skills, but unfortunately it has not been matched by ability to use digital media to obtain information and self development. The purpose of the research was to determine the extent to which students’ digital literacy skills, how to use digital literacy as a basis for religious moderation learning, and the obstacles faced during the training on the use of digital literacy at the Al-Hijrah Islamic Boarding School Tingkir Salatiga. This research is a qualitative and participatory action research. Data collection techniques used are participant observation, interviews, and documentation. The data analysis technique uses Mile and Hubermen in the form of reduction, presentation, and conclusions. The research procedure includes planning, implementation, observation, and reflection. The result of the studi show that digital literacy can be used as a basis for learning religious moderation. The students at the Al-Hijrah Islamic Boarding School can get digital content in the form of religious moderation material from website, social media, and others. The students also take advantage of digital literacy to create religious moderation content.

Resource Efficient Multi-Dimensional Cache Management Strategy in Content Centric Networks

CCN promises to solve many problems related to traditional network architecture with its receiver-driven, secure and simplistic model. Transparent and ubiquitous in-network caching, mobility management are two active research topics within CCN domain, and we intend to address both in this thesis. This document mainly consists of our work on improving in-network cache management in static and dynamic network environments. In-network cache management in Content-Centric Networking (CCN) has received signi cant interest from research community in recent years. On the positive aspect, it helps in increasing content availability and quality-of-experience (QoE) by reducing end-to-end delays, and reduces server load. On the other hand, opting the default approach, that is, store a content at every node on the delivery path is not resource-e cient as it introduces high cache redundancy. A multitude of schemes are proposed to increase e ciency of the network, which aim to reduce redundancy by selecting a small fraction of nodes on returning path for storing contents. This selection is generally based on taking into account knowledge about the network or the content itself. However, in many schemes node''s utility is generally determined by analyzing only one concept at a time. For example, some schemes store contents based on popularity, while others select nodes employing only the information about network topology etc. Considering only a single aspect while taking a decision may limit the scope of the cache management scheme to be deployed in diverse scenarios, and might result in sub-optimal performance when the environment is changed. Hence, there is a need to devise an e cient caching mechanism that can dynamically adjust and adapt itself to any environment. With this in mind, we propose an adaptive caching strategy, named as Multi-Attribute Caching Strategy (MACS) based on multi-parameters for CCN. MACS attempts to overcome ine cient cache utilization by intelligently selecting caching locations along the content delivery path. Simulation results show that MACS reduces cache load at each node while providing comparable delay and better cache hit rate using both synthetic and real network topologies. In second part of the thesis, we analyze the aspects of content-centric caching in Mobile Ad-hoc Networks (MANET). We propose a caching framework that dynamically adapt the caching decision of each content and relocate the replica if the old cached node moves to another location. We envision that such cache relocation mechanism to stimulate cooperation among nodes have potential to help with practical deployments in real scenarios.