Review Paper: A Study of Monotectic Al-Bi Alloys Rapidly Solidified from Melt

يقدم هذا البحث نتائج تجريبية واعتبارات نظرية لدراسة تأثير التبريد السريع من الذوبان على الخواص الفيزيائية لسبائك Al-Bi. تم الإشارة إلى عدد من سبائك Al-rich ثنائية أحادية التكتل ذات قابلية محدودة للذوبان في الحالة الصلبة على أنها مرغوبة في العديد من التطبيقات الصناعية ، على سبيل المثال ، المحامل ذاتية التشحيم والمواد الإلكترونية والموصلات الفائقة والمكونات البصرية. تخضع السبائك أحادية التوحيد لتفاعل ثابت عند درجة الحرارة الأحادية ، حيث تتحلل المرحلة السائلة ، L1 ، إلى مرحلة صلبة ، S1 ، ومرحلة سائلة ، L2. أثناء التبريد ، تتشكل المرحلة السائلة الأقلية بشكل متقطع وتعزل الألياف داخل المصفوفة. تم استخدام تقنية الغزل المصهور لقوالب التبريد لفحص إمكانية صب سبائك Al-Bi monotectic ذات البنية المجهرية المتجانسة المحتملة. تم تحليل البنية المجهرية الناتجة عن طريق مسح المجهر الإلكتروني وحيود الأشعة السينية. تم فحص المقاومة الكهربائية ، المتغيرات الحرارية ، الاحتكاك الداخلي ، الانتشار الحراري ، المعاملات المرنة وصلابة السبائك كدالة للتركيب. تكشف النتائج أنه يمكن توليد عدة صفات من القوة والصلابة والمحتوى الحراري وتغيير الانتروبيا والمقاومة والاحتكاك الداخلي لهذه السبائك واستخدامها  تطبيقات التي تحتاج الى مقاومة الاحتكاك.This paper presents experimental results and theoretical considerations to   investigate the effect of rapid cooling from melt on physical properties of Al-Bi alloys. A number of monotectic Al-rich binary alloys having limited solubility in the solid state have been pointed up as desirable for many industrial applications, e.g., self-lubricated bearings, electronic materials, superconductors and optical components. Monotectic alloys undergo an invariant reaction at the monotectic temperature, in which a liquid phase, L1, is decomposed into a solid phase, S1, and a liquid phase, L2. During cooling, the minority liquid phase forms discontinuous and isolate droplets or fibers within the Al-matrix. The competition between the growth of the minority phase and the rate of displacement of the solidification interface will determine if the prevalent morphology will be formed by droplets or fibers. Chill-block melt spinning technique was used to examine the possibility of casting Al-Bi monotectic alloys with possible homogeneous microstructure. The resulting microstructure was analysed by scanning electron microscopy and X-ray diffraction. The electrical resistivity, thermal parameters, internal friction, thermal diffusivity, elastic moduli and hardness of the melt-spun ribbons have been investigated as a function of composition. The results reveal that several combinations of strength, hardness, enthalpy, entropy change, resistivity and internal friction can be generated from the alloys to meet the needs of antifriction applications

The Qur'anic Purposes of Sheikh Abdul Rahman Hassan Habanka Al-Maidani in his Interpretation of Ma'arig al-Tafakkur wa-Daqa'iq al-Tadabbur ``Surat Al-Asr, Al-Adiyat, Al-Kawthar and Al-Takathur as a model"

This research aims to elicit Quranic purposes from the field interpretation of Sheikh Abdul Rahman Hasaan Habanka Al-Maidani by studying Surat Al-Asr, Al-Adiyat, Al-Kawthar, and Al-Takathur as a model. The knowledge of the purposes of the surahs leads to the realization of some of the notable purposes of the revelation of the Quran, the consideration of its phrases, words, and purposes, the statement of what Allah the almighty wants in it, and what its surahs and verses are guided to in a way that achieves understanding and action. Also, a statement that the number of the purposes of the surah does not depend on the number of its verses, there are several verses in common. In one objective, there is one verse in which there is more than one objective, so the Qur'anic objectives are inseparable from interpretation, since the Quran is the main source for defining the overall objectives, and from it deduced many ruling and partial ills, and it enables the interpreter to derive the rulings and wisdom of the Qur'an. The Noble Qur'an, considering the purposes of the surahs, is considered the safest approach, which makes the words of Allah the almighty orderly in a manner in which the perfection of its system, the coherence of its surahs, the consistency of its verses, and the statement of its inimitability and eloquence become evident. Keywords: Qur'anic purposes, interpretation, interpreter

Evolution of Middle Devonian Species of Euglyphella as Indicated by Cladistic Analysis

47-64http://deepblue.lib.umich.edu/bitstream/2027.42/48473/2/ID323.pd

Bacteria from contaminated urban and hilly areas as a source of polyhydroxyalkanoates production

Polyhydroxyalkanoates (PHA) production and extraction of different bacterial strains isolated from contaminated urban and hilly areas was conducted. The 30 bacterial isolates were Gram negative andbelonged to Pseudomonas, Citrobacter, Klebsiella, Escherichia and Enterobacter genera. Bacterial level of resistance against antibiotics (Penicillin) and heavy metals (zinc, cadmium and copper) was determined. Bacterial isolates from contaminated urban areas were found to be more resistant. The screening for PHA production was done by the Sudan black staining. Among the urban area isolates, U17, U8 and U9 produced highest concentration of PHA (50.4, 40.6 and 37.9%) while in hilly areaisolates H8, H6 and H9 showed highest production (45.8, 42.4 and 37.6%) by SDS digestion method. The percentage production was lowered when the extraction was done by sodium hypochlorite digestion method. Selected bacterial strains were optimized for PHA production at different growth conditions that is, pH, temperature and carbon sources. Bacterial isolates U8, U17 and H8 produced maximum amount of PHA 74, 69 and 59%, respectively, at pH 7, 37°C and using cooking oil as carbon source after 72 h. PHA polymerase phaC1/C2 genes were successfully amplified from genomic DNA of three bacterial isolates showing 540 bp DNA fragment which confirmed the presence of phaC1/C2 gene presence. It showed that the corresponding bacterial isolates would have been able to synthesizemedium chain length PHA

A molecular insight in sport and athletic alpha – actin3 gene in students of Physical Education Faculty and bodybuilders.

Alpha – actin3 is gene for athletic performance and sport. Three types of genotypes were identified within the gene: RR homozygous, RX heterozygous, and XX which lacks expression of these fibers. All three genotypes were identified among participants. Distribution of these genotypes was significant them, and it is noticeable that XX genotype was less in numbers than the other genotypes. BMI and BFP were in acceptable limits in athletes, but it was found to increase in control group with age. Two males and one female exhibited odd reading regarding muscle mass and testosterone level which was significantly higher than the others. Genetic analysis of these athletes showed SNPs that altered ORFs reading site, and production of different protein from the gene which affected muscle mass dramatically toward higher density, and triggered higher testosterone level in the body as an exceled response to intensive training. The three of them were found to be of XX genotype. Among athletic participants, physical fitness was high especially with young athletes. Most sprinters were found to be RR and RX genotype, while endurance athletes were of XX genotype. Significant SNPs at actin3 gene determined exceled athletes who were found to comprise less than 1%

CT and MR imaging in young stroke patients

Background: This study investigates the role of CT and MR imaging in the diagnosis and management of young stroke patients. Methods: CT scan findings of 108 patients and MR findings of 30 patients between 15-45 years of age were reviewed retrospectively. The variables included the territory of infarct on CT and MR imaging, the cortical distribution and size of infarct. Results: About 80% of the patients had infarcts of the carotid territory and 20% the vertebro-basilar distribution. More than half of the infarcts were cortical (56%). The yield of MR imaging was much higher for deeper structures such as basal ganglia, thalamus and brainstem. In half the cases, the infarct size was more than 3 cm. CONCLUSION: The ratio of carotid to vertebro-basilar infarcts was similar to that reported previously. A large proportion of the carotid territory infarcts were cortical. Deeper infarcts were better imaged with MR scan. There was a high proportion of large infarcts

Ischemic stroke in young adults of South Asia

Objective: To study the risk factors, etiology and management of ischemic stroke in young adults in a South Asian population. Methods: Retrospective study conducted at a large tertiary hospital in Karachi. One hundred and eighteen patients between fifteen and forty-five years admitted over a five year period with a diagnosis of ischemic infarct constituted the study population. The study variables included the full clinical spectrum, spanning historical, laboratory, radiological and outcome parameters. Results: Forty-three percent of patients were hypertensive and 30% were diabetic. The combination of diabetes and hypertension was found in 19.5% of patients, intra-cranial and carotid artherosclerosis in 22% and embolism in 11% of the cases. The in-hospital mortality was 11%. The outcome was excellent in 27%, good in 50% and poor in 23% of patients. CONCLUSION: The risk factors for artherosclerosis and the contribution of intra and extra-cranial artherosclerosis were found to be much higher than those from the Western Hemisphere

Exposure to NO2 in occupational built environments in urban centre in Lahore

Increased economic growth, urbanisation and substantial rise in automobile vehicles has contributed towards the elevated levels of air pollution in major cities in Pakistan. Aone week study was conducted by using passive samplers to assess NO2 concentration in occupational built environments at two most congested and populated sites of Lahore. Both sites were locatedon the busy roads of Lahore. At Site-I the highest concentration was in outdoors followed by corridor and indoor. While at Site II all the sampling location wereindoors and level were comparable to that of outdoor levelsat Site I. The results suggest the likely contribution of ambient sources in exposure to indoor NO2 in educational and other occupational built environments in urban centres