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Synthesis and Microstructural Studies of Fine Magnetic Particles

Thesis Info

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Author

Hafeez, Abdul

Program

PhD

Institute

University of Education

City

Lahore

Province

Punjab

Country

Pakistan

Thesis Completing Year

2008

Thesis Completion Status

Completed

Subject

Applied Sciences

Language

English

Link

http://prr.hec.gov.pk/jspui/handle/123456789/1163

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676727471661

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In the present work fine Zinc, Manganese and Cobalt ferrites particles were prepared using the co-precipitation technique. The synthetic technique involved the co-precipitation of iron (Fe3+) and metal (zinc, manganese and cobalt) ions from aqueous solutions using NaOH base to create fine MFe2O4 particles (where M stands for metal). This technique provides greater homogeneity of the particles. The microstructural studies were performed using x-ray diffraction technique. Samples of zinc ferrites were synthesized at different digestion temperature. The concentrations kept at 0.2M. Spontaneous magnetization of the samples was determined by using permanent magnet. The Spontaneous magnetization of the samples decreased with increase in the digestion temperature of zinc (Zn2+). The maximum magnetization was found for samples having digestion temperature of 55oC. Particle sizes for the magnetic samples were determined using Sherrer’s formula. The XRD patterns of all the samples showed very close resemblance with the ICDD card data. The particle size was found to depend on the digestion temperature . Particle size of the samples increased with increase in the digestion temperature from 55oC to 85oC while it decreased for the digestion temperature of 95oC. The surface morphology and magnetic properties were also performed using SEM and VSM. The magnetic properties of zinc ferrite samples resembled those of ideal soft ferrite with almost no hysteresis loss. Fine manganese ferrite (MnFe2O4) particles were prepared using the co-precipitation technique. Samples with concentrations of 0.1 and 0.2 were prepared. The particle sizes of prepared samples were determined by using Scherrer’s formula. The surface morphology and magnetic properties showed that the particles were of narrow size distribution and have good properties of soft ferrites. In order to synthesize Cobalt ferrite particles, chemicals of FeCl3.6H2O, CoCl2.6H2O and NaOH were used. The magnetization of substituted ferrite nano particles synthesized by co-precipitation depends mostly on parameters such as reaction temperature, pH of the suspension, initial molar concentration etc. Cobalt ferrite samples were prepared from the mixed Fe2+ and Co2+ solutions, which were made from their stock solutions and had a constant initial total iron ions concentration and amounts of Co2+ ions. The size and size distribution was controlled by controlling the nucleation and growth rates. Magnetic nanoparticles of cobalt ferrite have been synthesized by wet chemical method using stable ferric and cobalt salts. X-ray Diffraction (XRD) confirmed the formation of single-phase cobalt ferrite nanoparticles in the range 15–48nm depending on the annealing temperature and time. The cobalt ferrite was also subjected to microwave which resulted in soft to semi hard ferrite transition. The size of the particles increases with annealing temperature and time while the coercivity goes through a maximum, peaking at around 28 nm In order to find the effect of variation in the metal ion to hydroxide ion ratio on particle sizes, we synthesized Cobalt ferrite particles using chemicals of FeCl3.6H2O, CoCl2.6H2O and NaOH. The magnetization of substituted ferrite nano particles synthesized by co-precipitation depends mostly on parameters such as reaction temperature, pH of the suspension, initial molar concentration etc. To find the transition temperature, the behavior of the specimen and the formation of phase of the magnetic material, resistively measurements were made on the sample. We may conclude that the co-precipitation technique has resulted in very good soft ferrites of zinc, cobalt and manganese. The crystallite sizes were varied by varying the concentration ratios, changing digestion times, varying digestion temperatures and applying microwave digestion. The magnetic properties were found to be dependent on the particle size. The surface morphology showed that the defects were not observed in the samples.
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چھٹا باب: تہذیب و ثقافت

بنیادی رسوم رواج

          ایک مذہبی یہودی کی ساری زندگی مختلف رسومات میں منقسم ہے جو اس کی پیدائش سے لے کر اس کے مرنے کے بعد تک جاری رہتی ہیں۔ مشنانے اس زندگی کا خلاصہ درج ذیل لفظوں میں بیان کیا ہے:

پانچ سال کی عمر میں مقدس کتب کی پڑھائی، دس سال کی عمر میں مشنا کی پڑھائی، تیرہ سال کی عمر میں وصیتوں کی پیروی، پندرہ سال میں تلمود کی پڑھائی، اٹھارہ سال میں شادی، بیس سال میں ملازمت، تیس سال میں قوت کا عروج، چالیس سال میں دانائی، پچاس میں صلاح دینے کے قابل، ساٹھ میں بڑھاپا، ستر میں سالوں سے بھرپور، اسّی میں "ہمت" کی انتہا، نوے میں خم رسیدہ، سو سال میں مردے کی مانند اور اس دنیا سے کوچ۔[1]

باب ششم کے اہم نکات

  1. یہودی ثقافت کا تعارف۔
  2. بنیادی یہودی رسومات کا تعارف۔
  3. یہودیت میں شادی مرگ کی تقریبات کا تعارف۔
  4. یہودی کیلنڈر کا تعارف۔
  5. یہودی تہواروں کا تعارف۔
  6. اسرائیلی تقریبات کا تعارف۔
ابتدائی یہودیت میں کچھ رسومات مردوں تک محدود تھیں۔ عورت کو بعض عبادات میں شامل نہیں کیا گیا۔ مرد ہی کو گھر کا سربراہ مانا گیا۔ اکثر ربیوں کی دعاؤں میں بھی بیٹوں کا ذکر ہوتا ہے جس سے پتہ چلتا ہے کہ قدیم یہودیوں میں مردوں کو خصوصی اہمیت حاصل تھی۔ اس سے یہ بھی نہیں سمجھنا چاہیے کہ عورت کو کوئی وقعت نہیں دی گئی۔ یہودیت کا ابتدائی دور بزرگوں کا دور کہلاتا ہے۔ عمومی طور پر بزرگوں میں مردوں کو شامل کیا جاتا ہے لیکن مختلف روایات سے یہ بھی پتہ چلتا ہے کہ بزرگوں کے اس دور میں عورت کا کردار بھی اہم اور مقتدر تھا، مثلاً اس...

Personal Knowledge of a Judge As a Source of Proof: An Islamic Perspective

Islam has given pivotal role to the judiciary and considers it one of the most important pillar of the state. In this regard, the role of a judge is also of great importance as justice cannot be dispensed in society without the contribution of a judge. When a dispute is brought to a court, it becomes the responsibility of the judge to provide justice to the parties. A judge relies on testimony, oath and circumstantial evidences as sources of proof. Jurists have discussed them in detail while they have also discussed personal knowledge of a judge (Ilm al-Qadi) as a source of proof. This article focuses on it, where different stipulations and conditions, as laid down by the jurists, have been discussed along with their arguments.

Characterization and Bio-Evaluation of Some Indigenous Legume Protein Isolates for Complementary Foods

In present investigation, extraction, characterization and bio-evaluation of protein isolates from different indigenous legumes i.e. chickpea, lentil, broad and kidney beans were carried out to develop complementary foods. In tested legumes, after inactivation of anti-nutritional factors, protein isolates were prepared through isoelectric precipitation method. The highest protein yield as 80.47±5.71% was estimated in lentil protein isolates (LPI) followed by 73.14±3.44% in chickpea protein isolates (CPI) and 67.58±3.70% in broad bean protein isolates (BPI) while the lowest yield 52.83±3.36% was in kidney bean protein isolates (KPI). Moreover, protein isolates were assessed for their functional properties like bulk density, oil & water absorption, emulsifying & foaming properties etc. Maximum bulk density was revealed in LPI followed by CPI, KPI and BPI. Likewise, higher water absorption capacity was recorded in CPI tracked by LPI and BPI whilst the lowest in KPI. Maximum foaming capacity (FC) was revealed in BPI followed by KPI and LPI, respectively and the minimum in CPI. Electrophorogram through SDS-PAGE showed that legume protein isolates had protein bands in the range of 4 to 70kDa. Amino acid quantification was also performed with reference to requisite profile for the pre-schoolers. Among the essential amino acids, higher lysine content (4.54±0.21g/100g) was found in KPI followed by CPI (3.70±0.09g/100g) and LPI (3.66±0.20g/100g) whilst BPI showed minimum values (3.51±0.21g/100g). Simultaneously, amino acid scores were also determined with values of 39.6, 40.0, 40.0 and 56.0 in CPI, LPI, BPI and KPI, respectively. Bio-evaluation of respective isolates was performed through growth study parameters. Among the resultant protein isolates, the highest values were observed in LPI followed by CPI and BPI while the lowest for KPI regarding protein efficiency ratio (PER), net protein (NPR) and relative net protein ratio (RNPR), respectively for the year 2009-10. Similarly, nitrogen balance study parameters showed the highest values for true digestibility (TD), biological value (BV) & net protein utilization (NPU) in LPI tracked by CPI and BPI whereas the lowest values for these traits were recorded in KPI. However, BV value was high in KPI as compared to BPI. Similar trend for growth and nitrogen balance studies was observed in the next year 2010- 11. On the basis of overall yield, functional properties and bio-evaluation, two best protein isolates namely LPI and CPI were selected along with control for complementary foods preparation. The prepared formulations based on LPI (C1) and CPI (C2) congregated the FAO criteria for supplementary infant foods. The developed weaning foods were analyzed for chemical composition, energy value, bulk density, reconstitution index, viscosity and amino acid profile. Additionally, gross calorific values were observed as 401.70±20.42, 401.15±20.50 and 410.16±20.90kcal/100g for C1, C2 and control complementary foods, respectively. The essential amino acids were found to be sufficient in lentil and chickpea protein supplemented weaning foods. In addition to amino acid quantification for infant formulations, amino acid scores were also estimated. In complementary foods, maximum calorific value was contributed by fat followed by protein. Formulations in current study are capable of delivering 120.22±6.80, 122.49±6.36 and 123.27±6.09kcal per single meal for C1, C2 and control, respectively. Hedonic response regarding various sensory attributes also showed acceptance towards developed complementary foods. The acceptability appraisal of prepared infant formulations was conducted through short term infant feeding trial with the help of nursing mothers. The acceptability remained as 61.40 to 65.00% at the initiation of study and reached to 80.80 to 83.20% at the end of trial. Correlation studies also showed strong association among various variables and refelect their positive and negative contributions. The upshots of this project indicated that indigenous legumes have potential to yield protein isolates with appreciable functional and nutritional quality for application in array of foods with special reference to complementary foods.