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Preparation of Single Crystals of High Tc Superconductors by a Flux Method

Thesis Info

Author

Muhammad Maqsood

Department

Deptt. of Physics, QAU.

Program

Mphil

Institute

Quaid-i-Azam University

Institute Type

Public

City

Islamabad

Province

Islamabad

Country

Pakistan

Thesis Completing Year

1990

Thesis Completion Status

Completed

Page

87

Subject

Physics

Language

English

Other

Call No: DISS/M.Phil PHY/107

Added

2021-02-17 19:49:13

Modified

2023-02-19 12:33:56

ARI ID

1676717302769

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باب چہارم: معدنی وسائل کا مطالعہ

معدنیات کی اہمیت و افادیت

تعارف(Introduction)

معدنی کا لفظ معدن سے ماخوذ ہے۔ فیروز اللغات میں معدن کے لغوی معنی درج ذیل ہیں:

"کان-کھان- وہ جگہ زمین کھود کر دھاتیں۔ کوئلہ وغیرہ نکالیں۔ (جمع) معادن۔ "[1]

معدنیات کے لغوی معنی "وہ چیزیں جو کان سے نکلیں۔ دھات۔ فلّزات۔ "[2] ہیں۔

معدنیات کو اہم قدرتی وسیلہ کہا جاتا ہے۔ پاکستان معدنیا ت سے مالا مال ملک ہے اس لئے وطن عزیز میں معدنیا ت کے امور طے کرنے کے لئے معدنیات کی وزارت قائم کی گئی ہے۔ معدنیات میں سونا، چاندی، لوہا، تانبا اور نمک وغیرہ شامل ہیں۔ معدنیات کے ذخائر کسی بھی ملک کی ترقی و خوشحالی میں انتہائی مثبت کردار ادا کرتے ہیں۔ مسلم ممالک میں معدنی ذخائر کی بھرمار ہے لیکن ملت اسلامیہ کا المیہ یہ ہے کہ یہ ممالک جدید سائنس و ٹیکنالوجی میں مغربی ممالک کے ہم پلہ نہ ہونے کےباعث اپنے معدنی ذخائر کے اخراج کے لئے ان کے زیر تسلط ہیں۔ جدید ٹیکنالوجی سے لیس ہونا ملت اسلامیہ کے لئے ایک چیلنج کی حیثیت رکھتا ہے۔

علم معدنیات (Mineralogy)

انسائیکلوپیڈیا آف بریٹانیکا میں علم معدنیات کی تعریف یوں بیان کی گئی ہے:

“Mineralogy: scientific discipline that is concerned with all aspects of minerals , including their physical properties , chemical composition, internal crystal structure , occurrence and distribution in nature , and their origins in terms of the physicochemical conditions of formation.”[3]

علم معدنیات سے مراد ایسا سائنسی علم ہے جس میں معدنیات کے بارے میں تمام پہلوؤں کا مطالعہ کیا جاتا ہے۔ اس میں معدنیات کےطبعی خواص، کیمیائی ساخت، اندرونی کرسٹل ڈھانچہ کی تشکیل وغیرہ کا احاطہ کیا جاتا ہے۔

انسائیکلوپیڈیڈک ڈکشنری آف...

Hybrid Warfare and its Impacts on Pakistan

In modern times, the conventional means of warfare are increasingly becoming less usable. However, the states are involved in waging hybrid warfare to the maximum to fulfill their foreign policy goals. In nuclearized South Asia, direct war between India and Pakistan seems unlikely given that both the states know that escalation could lead to nuclear catastrophe in the region. This compels both the states to find other means of warfare to undermine each other’s interests. India wants to weaken Pakistan so that it may abandon claim on Indian occupied Jammu and Kashmir. For that, India is using all tools of hybrid warfare against Pakistan. In this context, this paper aims at to unearth India’s hybrid warfare in the region and its implications for Pakistan. The main focus of the paper is to explain tools and methods of India hybrid warfare. At the same time the research also tries to unravel few other case studies. It also notes how Pakistan can counter hybrid threats posed by its arch rival.

Evaluation and Optimization of Mixed Wheat Flour in Relation to End Product Quality

Lack of soft wheat variety and classification of wheats according to end product, baking industry faces continuous problems with the stability and quality of products. The current research work was undertaken to characterize different (six) Pakistani wheat varieties for physicochemical, rheological, nutritional characteristics and to check multivariate association among these characteristics with special reference to cookie quality prepared from wheats of varying extraction rates (study-I). In study-II, different levels of chemical treatments (sodium stearoyl 2-lactylate (SSL), L-cysteine and Lecithin) and shortenings (fat, oil, and margarine) were applied on mixed wheat flour to choose best level on the basis of sensorial and physical characteristics of cookies. Furthermore, selected levels of chemical treatments, shortening and physical treatments (heat) were compared regarding sensory, physico-chemical and nutritional attributes of cookies (study-III). Significant variation among wheat varieties were observed with respect to particle size index (PSI), thousand kernel weight (TKW), test weight (TW), pearling value, water solvent retention capacity (WSRC), sodium carbonate solvent retention capacity (SCSRC) and dough rheological parameters. Fatty acids like, Stearic, Elaidic, Caprylic acids were observed abundantly in wheat flours, and comparatively better fatty acid profile was observed in “Punjab 2011” and “Galaxy 2013”. Cookies prepared from flours of varying extraction rate imparted significant variation on color and overall acceptability of cookies while interaction of wheat variety and extraction rate imparted significant (p<0.05) variation on taste and texture of cookies. In most of the sensory parameters, it was observed that cookies prepared from high extraction rate i.e. 72-74% (stream split flour) gained high score and among wheat varieties, cookies prepared from flour of “Millat 2011” attained better score than cookies prepared from flour of other wheats. Spread factor (SF) of cookies was correlated with PSI (r = -0.63), pelshenke value (r = -0.62), water absorption (WA) (r = -0.60) and mixographic peak height (MPH) (r = 0.85).Principal Component Analysis (PCA) showed that PC1 accounted for 30.68% of variation for MPH, SF, peak viscosity, breakdown viscosity and damaged starch being the major factors. While, PC2 accounted for 21.29% variation with flour rheological properties like dough development time, dough stability, pasting temperature, trough viscosity, falling number and TW were the major factors. Based on sensory and physical characteristics (diameter, thickness, spread factor and textural hardness), it was concluded that “T1” (SSL @ 0.5%), “T4” (L-cysteine @ 0.5%), “T9” (oil + margarine) and “T11” (lecithin @ 1%) provided better quality cookies when applied on mixed wheat flour during study-II. In study–III, significant deviation in physical parameters like diameter (3.96-4.66cm), thickness (0.99-1.21cm), spread factor (37.32-46.03), color like L* (58.99-70.01), a* (0.80-2.61), b* (15.36-22.37) and hardness (2.09-2.89) of cookies was observed due to selected treatments. Among these, cookies prepared from Lecithin (@ 1%) and SSL (@ 0.5%) got high score in sensory evaluation, in textural hardness cookies prepared with SSL showed better results and regarding spread factor of cookies best results were observed in SSL (@ 0.5%) and in lecithin (@ 1%). Among fatty acids of cookies, abundantly found fatty acids were palmitoleic acid, stearic acid, myristoleic acid and oleic acid. Highest amount of palmitoleic acid (9.84%) and stearic acid (8.81%) was observed in “T4” (Lecithin @1%) while least amount was observed in “T3” (oil + margarine) and “T1” (SSL @ 0.5%) respectively. Therefore, current study suggested that SSL @ 0.5% and lecithin @ 1% can be incorporated in cookie recipe to minimize variation (occurred due to mixed wheat flour) in quality attributes of cookies.