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Home > Synthesis and Characterization of Cobalt Ferrite Nanostructures

Synthesis and Characterization of Cobalt Ferrite Nanostructures

Thesis Info

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Author

Rahman, Atta Ur

Program

PhD

Institute

Pakistan Institute of Engineering and Applied Sciences

City

Islamabad

Province

Pakistan

Country

Pakistan

Thesis Completing Year

2014

Thesis Completion Status

Completed

Subject

Applied Sciences

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/2427/1/2965S.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676727443679

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Coprecipitation method was used to prepare pure and doped CoFe 2 O 4 nanoparticles. Ferric and cobalt salts were used as precursors while oleic acid was used as surfactant. X- ray Diffraction and Transmission Electron Microscopy analysis confirmed single phase of nanoparticles with particle size ~20 nm. Electron transport in CoFe 2 O 4 nanoparticles was investigated using impedance spectroscopy from 300 K to 400 K over wide frequency range (20 Hz - 2 MHz). Impedance spectroscopy of CoFe 2 O 4 nanoparticles revealed a semiconductor to metal transition at ~330 K. The semiconductor to metal transition was attributed to existence of mixed valance states of Fe cations, reverse cation distribution among octahedral and tetrahedral sites and various types of interactions between these cations. Variation of exponent “s” with temperature suggested that overlapping large polaron tunneling was the dominant conduction mechanism in cobalt ferrite nanoparticles. The Mössbauer spectroscopy demonstrated the mixed inverse spinel structure of the CoFe 2 O 4 nanoparticles. X-ray Photoelectron Spectroscopy analysis was carried out to study the oxidation states and environment of Fe and Co cations. Electrical properties of Sn 2+ and La 3+ doped CoFe 2 O 4 nanoparticles were studied in detail. The change in dielectric constant and ac conductivity of CoFe 2 O 4 nanoparticles were observed with dopant concentration. The temperature induced delocalization of charge carriers and metallic phase in Co 0.6 Sn 0.4 Fe 2 O 4 nanoparticles was explained using M(H) loops and impedance spectroscopy. Metallic nature of Co 0.6 Sn 0.4 Fe 2 O 4 nanoparticles above 360 K was attributed to dominancy of delocalized charge carriers Fe 3+ –Fe 2+ /Co 3+ – Co 2+ interactions over localized charge carriers Fe 3+ –O 2− –Fe 3+ /Co 2+ –O 2− –Co 2+ interactions. This was suggested that the wasp - waist magnetic hysteresis loop was due to simultaneous existence of ferromagnetic and antiferromagnetic domains in the system. The M(H) loops of Co 0.6 Sn 0.4 Fe 2 O 4 nanoparticles indicated that at lower temperatures the superexchange interaction was dominant as compared to double exchange interaction while at higher temperatures double exchange interaction becomes more strong. The open M(H) loops of Co 0.6 Sn 0.4 Fe 2 O 4 nanoparticles indicated the absence of magnetic saturation. The temperature dependent electrical behavior of the grain boundaries was reported and discussed in terms of depletion space-charge layer in the vicinity of grain boundaries.
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ساتھوں کی انہونی ہو گئی

ساتھوں کی انہونی ہو گئی
سجناں کنڈ وکھاؤنی ہو گئی
اگے تاں سی رج کے سوندے
نیندر ہن پروہنی ہو گئی
عشق نوں نہ سوکھلّا جانو
پنڈ دکھاں دی چائونی ہو گئی
دکھاں باہجوں سکھ نہیں ملدے
شرط ایہو آزمائونی ہو گئی
منگن بھیک حسن دا دن نوں
راتیں دھونی لائونی ہو گئی
ہکے پاسے سیک جگر نوں
روٹی ہُن پرتائونی ہو گئی
پتہ حنیف نوں مل کے لگا
دُکھاں دی ایہہ چھائونی ہو گئی

Varietal Comparison of Proximate Composition and Mineral Profiling of Pakistan Native Barberry Powder Proximate Composition and Mineral Profiling of Barberry Powder

Berberis Vulgaris fruit (barberry)also commonly known as “zereshk” is one of the world’s renowned medicinal plant with highly nutritious and therapeutic values, world widely. It is an elongated, 8-10mm long, bright red colored, fruit. Berberidaceae family; B. Vulgaris fruit is very useful tonic for liver, heart, pancreas, gallbladder and kidneys. It prevents chronic bleeding disorders, purifies blood, lowersblood cholesterol level, blood pressure and most importantly it help to treat diabetes. In addition it is effective in treatment of parasitic liver, kidney stones, gout, colon cancer, prostate inflammation, fever, asthma and malaria. Objective: This study is aimed to check the mineral and chemical profiling of Pakistan native barberry fruit. Methods: Proximate analysis of three different varieties (BVF01, BVF02, and BVF03) of B. Vulgaris fruitfrom different three regions Azad Kashmir, Chitral and Gilgit Baltistandemonstrated a nutritional composition in range of 77.43, 70.08, 73.12%for moisture, 0.98, 0.76, 0.89% for crude ash, 0.42, 0.33, 0.39% for crude fat, 1.53, 1.32, 1.44% for crude protein, 2.76, 2.64, 2.75% for crude fiber, 16.88, 24.87, 21.41% for Nitrogen free extract (NFE). The different varieties of barberry contained the ranges of minerals such ascalcium2724.70,2584.13, 2693.59ppm, magnesium 998.46,944.06, 986.32ppm, potassium12189.75, 11,114.21, 12021.19ppm, sodium 1402.16, 872.38, 1269.44ppm, iron 449.67, 334.58, 396.90ppm, zinc8.42, 13.78, 29.5ppm, copper 15.11, 5.45, 11.63ppm, manganese 32.5, 25.86, 28.91ppm(mg/L), respectively. Conclusions: The type of barberry cultivated in Azad Kashmir is the best having good proximate composition and highest minerals amount as compared to Chitral and Gilgit Baltistan cultivated barberry

Predictive Role of Personality Traits in Compulsive Buying Behavior: Mediating Effect of Attitude Towards Advertising

Compulsive buying behavior is a phenomenon that has received significant attention of the researchers in the field of psychology, consumer behavior and marketing. It is an addictive propensity arises from the urges for buying something. Under this behavior buying is a source of relief from stress but ultimately disturb usual functioning. Researchers concluded that compulsive buying behavior is goal-oriented behavior and it depends upon psychological and environmental stimuli. The current study analyzes the psychological viewpoint of consumer?s compulsive buying behavior.Study also analyzes how attitude towards advertising is related with compulsive buying behavior and personality traits.Current study is valuable to the literature in following ways. Firstly, study presents broad dialogue on consumer?s compulsive buying behavior. Secondly, it discusses the bearing of personality traits on the psychological motives of consumer and it also discusses the role of attitude towards advertising on the psychological motives i.e. compulsive buying behavior. Thirdly, framework of the research verifies the social cognitive theory and acknowledges that cognitions and environment has strong effect on the consumer buying behavior and development of personality traits. Data for current study is collected from a sample of 250 shoppers of departmental stores. Out of 250 responses 210 found as complete and included in data analysis. Regression analysis employed to test hypotheses and Baron and Kenny?s (1986) method is adopted to test mediation. The results suggest that consumer?s personality traits have significant association with compulsive buying behavior as well as attitude towards adverting is an important construct to understand the association of personality traits and compulsive buying behavior. Results of the study expressed that attitude towards advertising act as partial mediator in the relationship of compulsive buying behavior and personality traits. Current study is a valuable addition in the literature of marketing research and the finding of the study would be helpful for researcher, retailers, decision makers and advertisers. Implication for policy makers would be development of consumer laws. Advertiser and decision authorities are directed to devise educational programs form such consumer to protect them from negative consequences. As in extreme conditions compulsive buying behavior leads to severe financial problems.For researcher it is beneficial for the further understanding of the compulsive buying behavior in context of personality traits.