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Home > Fabrication of Al-Cnts Mmc by Induction Melting With Improved Dispersion and Wetting of Cnts in Al Matrix Using a Multifunctional Flux

Fabrication of Al-Cnts Mmc by Induction Melting With Improved Dispersion and Wetting of Cnts in Al Matrix Using a Multifunctional Flux

Thesis Info

Access Option

External Link

Author

Mansoor, Muhammad

Program

PhD

Institute

National University of Sciences & Technology

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/123456789/7626/1/M.%20Mansor%20Full%20Thesis.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676726189382

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Aluminum/carbon nanotubes (Al-CNTs) composite is an encouraging candidate material for aerospace applications due to its expected high strength-to-weight ratio. Carbon nanotubes (CNTs) offer remarkable reinforcements owing to their high specific strength and specific modulus. However, uniform dispersion and wetting of the CNTs is extremely difficult in molten aluminum, due to large difference in surface tension forces of the two components. In present work, the dispersion issue was improved using induction melting technique, where innate stirring action of induction melting dispersed the nanotubes in molten aluminum. The wetting was improved using a multifunction flux (titanate of potassium), which, when was incorporated in molten mixture of aluminum and CNTs having, instigated in-situ reactions to form titanium carbides on the surface of the nanotubes causing increased wetting of CNTs by molten aluminum. The composites were characterized using scanning electron microscopy, x-ray diffraction, transmission electron microscopy and mechanical testing. Refinement in crystallite size was achieved down to ~150 nm and a corresponding increase in lattice strain up to ~3.46x10-3 was observed in the composites. A simultaneous increase in v i yield strength ~208 %, tensile strength ~218 %, and hardness ~100 % was observed. However, the decrease in the ductility of the composite associated with the strengthening of the matrix was <25 %. Additionally, stress relaxation behavior of the annealed composite was improved by ~30 % compared with pure aluminum. Consequently, the stress relaxation rate of the composite was decreased even beyond the yield strength of the annealed pure aluminum. Therefore, induction melting and usage of the flux for improvement in the dispersion and wetting of the nanotubes, respectively, appeared to be a potential method to fabricate Al-CNTs composites.
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المبحث الثالث: طلاقها

المبحث الثالث: طلاقها

 کانت حیاۃ الشاعرۃ مشتتۃ بین الفرح والحزن، فکانت کل یوم قصۃ جدیدۃ في حیاتھا، واستمرت الخلافات بین بروین شاکر وزجھا، وکان زوجھا یطلب منھا أن تضحي بوظیفتھا وبشعرھا من أجل الزوج والسعادۃ الزوجیۃ، والشاعرۃ کانت ترید أن توفق بین البیت والعمل والشعر، ولکن لم تستطع النجاح بین ھذہ الأمور کلھا۔

 کانت بروین شاکر إنسانۃ بارعۃ ذات طموح عالِ وفي نفس الوقت رؤوفۃ وحنونۃ، وأیضاً نصیر علي کان إنسانًا ھادئًا ولطیفًا وطیب القلب، ولكن الإثنين لھما أعمالھما وحیاتھما ووظائفھما وأفکارھما الخاصۃ مختلفان عن بعضھما البعض۔

 أشتھرت الشاعرۃ في ساحتھا الأدبیۃ والشعریۃ بإسمھا وشخصیتھا ولکن لم یعجب ذلك زوجھا، فأحسّ بالغیرۃ، ثم وصلت أعمال الشاعرۃ إلی الجرائد والتلفزیون والمقابلات الشخصیۃ، والحوار الذاتي بین الشاعرۃ والمذیعین کل ھذا زاد علی زوجھا من الحسد والغیرۃ، ولکن الشاعرۃ تعبت من ھذہ المشاجرات والخلافات الزوجیۃ وکانت لا تستطیع ان تتراجع وتترک الحیاۃ الأدبیۃ لأنھا الآن وصلت إلی قمم الإبداع والفن الأدبي ولکن في نفس الوقت کثرت مشاکلھا وتبعثرت حیاتھا الزوجیۃ فلذلک إنتقلت من کراتشي، وجاء ت واستقرت في إسلام آباد، حاول زوجھا إصلاح الخلافات ولم ینجح، وفي 1987 جاء نصیر علي إلی بروین ومعہُ أوراق الطلاق، فأراد من زوجتہِ أن توقع علی ھذہ الأوراق وکان من أول شرائط الطلاق بأن بروین إذا تزوجت برجلٍ آخر فستحرم من إبنھا (مراد) الذي کان وحیدھا، فتم الطلاق بین الزوجین في 1987م وکان ذلک آخر لقاء بینھما[1]، وھذا من بعض أشعارھا، ما أجمل قولھا عند ما قالت:

وہ تو خوشبو ہے ہواؤں میں بکھر جائیگا

مسئلہ پھول کا ہے پھول کدھر جائیگا

 

 

الترجمۃ:

 ھو ذاک الریح العطر سینتشر في الھواء

 فماذا عن بقاء الزھرۃ،...

اسلامی نقطہ نظر سے ماحولیاتی نظام کی پائیدار ترقی: ایک تحقیقی مطالعہ

In globalization and information age, Sustainable development is a contemporary issue to protect future generations. Islam is not only a religion, but also a guideline for whole life and is based on divine principles of Shari‘a that also address sustainable development to mankind. Indeed many values and principles that have been central to Islam are inclined towards prosperity of people and development of society. On other hand Industrial revolution brought a huge destruction on the earth because in capitalist system people are self concerned rather than society. Islamic social responsibility teaches lesson of unity and called a mankind an ummah (community) and a moderate ummah, who is not allowed to make any mischief on the earth. Everything on the earth is gifted by Allah to the mankind and man is the deputy of Allah and become a steward (khal┘fah) for the earth, now it is his responsibility to save the world from any harm. The main objective of this research is to present the principles and applications of Islam in sustainable development debate especially on ecological aspect.

Assessment of Biological Properties of Bone Marrow Mesenchymal Stromal Cell by Ex-Vivo Expansion and Differentiation

Mesenchymal stromal cells (MSCs) represent a rare population of multipotent stem cells found in many adult tissues. In bone marrow MSCs support haematopoiesis by providing marrow stroma. MSCs have recently emerged as an exciting candidate for cellular therapy due to their hypoimmunogenic properties and ability to differentiate into different tissue types. With the intent of optimizing large-scale expansion of MSCs for clinical use, we compared different culturing conditions for their ability to support growth and proliferation of bone marrow MSCs (BM-MSCs). We evaluated cells cultured in Alpha Modified Eagle Medium (αMEM), Dulbecco’s modified Eagle medium (DMEM) in the presence of either 10% fetal bovine serum (10% FBS), 10% pooled human platelet lysate (10% pHPL) or commercial serum-free formulation (StemPRO® MSC SFM). We concluded that supplementing growth medium with pHPL resulted in superior cell yield than fetal bovine serum (FBS) and comparable to commercial serum-free formulation. Study II was a phase-I human clinical trial, establishing safety of autologous BM-MSC transplantation in nine spinal cord injury patients. For this ex vivo expanded MSCs were injected intrathecally after premedication. All of our patients tolerated the procedure well and no complication was observed during a median follow up of 644 days. Some of the patients with sub-acute disease reported subjective improvement in sensory and neurological functions. Lastly we carried out a phase-I/II trial of MSCs in allogeneic use as a treatment option in treating steroid-resistant graft versus host disease (GVHD). GVHD is a life threatening complication of allogeneic stem cell xii transplantation and only a fraction of patients are cured through steroids. Those who fail to respond to steroid have a very poor prognosis. The patients received third party BM MSCs as their bone marrow MSCs were failing to cope with the immunemediated tissue destruction by donor T cells. A total of 33 MSC infusions were given to 10 patients suffering from acute GVHD (n=3), chronic GVHD (n=5) and overlap syndrome (n=2). Eight out of ten patients are alive after a median follow up of 11 months with five having sustained CR. Three patients with partial response received further doses to sustain response. One of them died of lung infection while others are still alive. One out of the two non-responding patients died after 17 days of MSC therapy due to advanced liver GVHD while the other is having stable disease course. The overall and disease-free survival was 80% and 50% respectively. The patients developed no complication or toxicity related to MSC infusion. Luminex analysis revealed a modest drop after MSC infusion in pro-inflammatory cytokines like IFNγ, TNFα, IL-1β, IL-2, IL-4, IL-6, IL-17A and IL-17F, whereas serum IL-10 levels were slightly raised. Overall a total of 57 preparations of cultured stem cells were made which were transplanted via I.V. or I.T. route with no adverse event or serious complication to report. Therefore it is concluded that MSCs can be safely given in both autologous as well as allogeneic setting as cellular therapy in selected clinical situations. This initial data on safety and efficacy calls for taking these clinical trials into advanced phase with more detailed account of efficacy measures and addition of placebo groups.