Direct carbon fuel cell directly converts the chemical energy stored in the fuel (carbon) to electricity. It is a high-temperature fuel cell having practical efficiency of 80%, normally operates at or above 700 oC with significantly low CO2 emission compared to coal burning power plants which release large amount of notorious gases NO2, SO2 and CO2. In this PhD research work main objectives are to synthesize combination of efficient electrolytes and electrodes materials not only operational compatible with carbon fuel, but also are electrochemical stable, having high conductivity and should provide excellent performance. Further, this thesis is divided into three parts; Electrolytes, Electrodes and theoretical calculation. Therefore, commonly used coprecipitation technique has been employed to synthesize various electrolytes, calcium doped ceria, single carbonate- doped ceria, binary carbonate-doped ceria, and ternary carbonate-doped ceria, barium co-doped ceria, calcium co-doped ceria, magnesium co-doped ceria and strontium co-doped ceria. However, in addition to electrolytes mainly two types of electrodes known as oxides LiNiCuZnO (LNCZO), LiNiCuZnFeO (LNCZFO) and perovskite LaSrNiTiO3-d (LSNT), LaSrFeTiO3-d (LSFT), LaSrCoTiO3-d (LSCT) and LaSrZnTiO3-d (LSZT) have been prepared using sol-gel technique. The prepared materials are characterized using various structural techniques; X-ray diffraction (XRD), Scanning electron microscopy, Thermal analysis, UV-Visible spectroscopy, Raman spectroscopy, Fourier transforms infrared spectroscopy, DC/AC conductivity and electrochemical performance. On the top of all characterization the XRD results reveal the prominent cubic structure of all the electrolytes and perovskite electrodes, whereas composite structure of LNCZO and LNCZFO is confirmed. Moreover, two types of carbon fuel categorized as coal based (lignite, bituminous, sub-bituminous) and waste biochar (walnut shells, almond shells) have been used to evaluate the overall electrochemical performance of direct carbon fuel cell (DCFC). xi Amongst all the discussed electrolytes (Li,Na)2CO3–doped ceria(LN-SDC) has shown the highest ionic conductivity of 0.31 Scm-1 with maximum performance of 617 mWcm-2 in combination of LNCZO electrode at 600 oC forhydrogen as fuel and air as oxidant. Secondly the combination of co-doped ceria electrolyte calcium co-doped ceria (CSDC) and LNCZFO electrode had depicted the performance of 630mWcm-2 at 650 oC with hydrogen fuel, where as co-doped ceria electrolyte (CSDC) has shown highest ionic conductivity of 0.124 Scm-1. Nevertheless in comparison above mentioned electrolytes LN-SDC with LNCZFO electrodes exhibited a performance of 58mWcm-2 for sub-bituminous fuel. Instead of obtained power densities of the cell comprised of cathode-electrolyte- anode (LSCF|LN-SDC|LSFT) are 78,73,57,29 and 26 mWcm-2 at 700 oC with fuel as sub-bituminous, walnut shells, almond shells, bituminous and lignite respectively. The prepared LSFT and LSCT also have been tested as cathode which shows good performance with carbon fuel. Further to elaborate, theoretical calculations using Density Functional Theory (DFT) technique are performed to co-relate the effect of structure, dopant radius, lattice constant of doped system, density of states and band gap with the experimental results and at some point both DFT simulation and experimental results have shown the best match in terms of increase in lattice constant by decreasing band gap
ابھی آنکھوں کے دریچے کم سن اور عقل کے جگنوئوں کی روشنی مدھم تھی ،جب دل کی تاریک گلیوں سے یہ خیال اکثر کسی انجان مسافرکی طرح گزرتا کہ یہ بھٹکے ہوئے لفظوں کے سوداگریونہی کہنہ کتابوں کا بوجھ اٹھائے پھرتے ہیں ۔ان کی سطریں طلسمی افسانوں کے سوا کچھ نہیں ۔ان کی باتیں فریب کی واضح دلیلوں کے سوا کچھ نہیں ۔بھلا لفظوں کے لمس سے کسے شفا ملی ہے ؟بھلا جملوں کی تپش سے کب پتھر پگھلے ہیں ؟مگر اک روز میں اداس شام کے غمزدہ حجرے میںجونؔ کے صحیفہ’’شاید‘‘ میں موجودغزل(نیا اک رشتہ پیدا کیوں کریں ہم) کے ابتدائی اشعار کی قرأت میں منہمک تھا تو مقدس پردوں میں لپٹی ، پہلی معصوم آیت نے مجھ پر کھلتے ہوئے گواہی دی’’یہ خدا کے چنیدہ لوگ ہیں‘‘۔
دوستی جو کبھی محبت کے مہکتے پھولوں کا جزیرہ ہوتی تھی ۔ا ب د لکش مگر آتشی سانپوں کا جنگل بن چکی ہے ۔میں چاہتا تو لفظوں کی بین کے زور پر منتروں سے جکڑی پٹاری میں انھیں قید کر سکتا تھا لیکن دانستاً ایسا نہیں کیا۔یہ یونہی چاہت کا ملاوٹی دودھ پی کرنیلی رگوں میں زہر اتارتے رہیں۔میں نہیں چاہتا تھا یہ سانپ جن کی مفادی آستینوں میں پل رہے ہیں وہ میرے چاکِ گریباںکو اور تار تار کریں ۔
میں اکثر سوچتا اگر خدا نے یہ جدید حرف گر(ن۔م راشدؔ ،مجید امجدؔ،میرؔا جی )نہ بھیجے ہوتے،تو میرے لیے بھٹکنا کتنا آسان تھا۔میرے بہت سے ژولیدہ خیالات اور کومل جذبات الفاظ کا پیراہن زیب تن کیے بنا غزل کی روایتی گلیوں میں سراسیمگی اوڑھے دربدر کی ٹھوکریں کھاتے یا پھر کسی روز دل و دماغ کی کسی کنج میں لاوارث لاش کی طرح پائے جاتے۔
يكشف هذا البحث عن أن تجربة الوحي ليست تجربة عادية، بل هي تجربة من مستوى فوق طبيعي، وإن استكناه حقيقة الوحي أمر متعال، وغير قابل للخضوع إلى أي نوع من أنواع المعرفة الإنسانية. على نحو، أن هذا الوحي القرآني يقدم أصول منهج متكامل في التعامل مع التاريخ البشري. علاوة على ذلك فقد تناول القرآن المسألة التاريخية ضمن العديد من سياقات سوره وآيه، تدرجت بين سرد أحداث القصص القرآني، والعرض المباشر لتجارب السابقين سواء كانوا أفرادا أو جماعات، انتهاء إلى استخلاص القوانين التي تحكم الظواهر الاجتماعية التاريخية. ولتحقيق أهداف البحث استخدمت الباحثة مقاربة تحليلية تهدف إلى تفكيك الظواهر ودراستها دراسة تفصيلية. وقد توصل البحث إلى مجموعة من النتائج أهمها أن حدثا كان له تأثير كبير عل تشكيل، ورسم معالم الفكر والتاريخ الإنسانيين يتمثل في القرآن بما يجليه من تأثير في مجمل مراتب ومناحي هذا الفكر، بل يمكن التأكيد أن التاريخ البشري قد تميز، بقوة، بحدث سجل حضوره القوي وبصم تأثيره عبر العصور المتلاحقة، وسيظل كذلك، هو القرآن الكريم.
Introduction: Rheumatoid Arthritis, one of the commonest forms of inflammatory arthritis, has significant societal impact with regards to cost, induction of disability and loss of productivity. This impact is magnified in the presence of comorbid mood disorders, as these constitute independent factors for unexplained flares and relapses.
Purpose: The primary purpose of this study was to determine the correlation between disease activity and depression in Rheumatoid Arthritis patients.
Methods: Patients with Rheumatoid Arthritis attending rheumatology clinic at Aga Khan University Hospital, Nairobi were recruited into the study. The patients’ disease activity and functional status were assessed using the Clinical Disease Activity Index and the Stanford Health Assessment Questionnaire respectively, whereas the level of depression was evaluated using the Patient Health Questionnaire-9. Pearson’s correlation coefficient was calculated for the disease activity and functional status versus the depression scores, and relationship between the disease activity and depression scores was analyzed using Chi square tables.
Results: A total of 60 patients were enrolled into the study, whose mean age was 48.8 ± 13.6 years. There were 52 females (86.7%). The mean duration of RA symptoms was 71.6 ± 86.6 months, with the mean duration of RA treatment being 43.4 ± 64.5 months. Among the study participants, 28.3% had mild depression whereas 35% had moderate/severe depression. There was a strong positive correlation between disease activity and depression (? < 0.001), as well as between physical disability and depression.
Conclusion: This study found depressive symptoms in 63.3% of the patients, in spite of the study population being relatively young and having short duration of disease. The significant correlation observed between disease activity and depression illustrates the high likelihood of undiagnosed comorbid depression as a co-existing factor in persistently active disease, poor response to therapy and unexplained flare-ups in the Kenyan Rheumatoid Arthritis population.