Tungsten carbide cobalt coating has been extensively used for cutting and mining tools, aerospace, automotive and other wear resistance applications. These coatings not only have superior mechanical properties like high hardness, toughness and compressive strength but have also excellent controllable tribological properties. Nanocrystalline coatings can provide combination of high hardness and high toughness which otherwise are exclusive properties. But in the case of High Velocity Oxyfuel (HVOF) sprayed nanocrystalline WC-cobalt coatings, a higher degree of decarburization is reported in the published literature. This results in porosity and brittle phases formation in the coating structures. This in turn results in higher wear rate of nanocrystalline WC-cobalt coatings. In this study HVOF sprayed coatings made from duplex cobalt coated near-nanocrystalline WC-cobalt powders is used. The purpose of using these powders is to address the issue of decarburization and porosity formation in the coatings. Lower decarburization and hence porosity formation in these coatings along with the benefit of smaller WC grain sizes result in better tribological performance of these coatings. A comparison of wear behaviour is made between conventional microcrystalline and novel duplex cobalt coated near-nanocrystalline WC-17 wt% cobalt coatings. Coatings made from finer and coarser feedstock powders with same WC grain size are also compared. Optical and Scanning Electron Microscopic images show more porosity in the microcrystalline coatings than the duplex coated WC-cobalt coatings made from coarser feedstock powders while the highest porosity was observed when fine feedstock powder having agglomerate sizes 10-20 μm with 300-550nm WC grain sizes were used. Fracture toughness was 25.12 and 19.04 MPam 1/2 for near-nano and microcrystalline coatings respectively while it was only 3.01 MPam 1/2 for the coatings madeiv from fine feedstock powders. The higher toughness can be attributed to more frequent interruption in the crack propagation and only intergranular cracking in the near- nanocrystalline coatings in contrast to the microcrystalline coatings where both trans-granular and inter-granular crack propagation take place. Under similar test conditions, the wear rate was 4.0×10 -3 mm 3 /m for nearnanocrystalline and 6.6×10 -3 mm 3 /m for microcrystalline coatings. The lower wear rate in duplex cobalt coated near-nanocrystalline coatings can be attributed to its higher toughness and hardness values, the lower decarburization and porosity observed in it and the smaller fraction of brittle non-WC phases formation. In summary it is stated that the lowest porosity, W 2 C content and lower wear rate and highest hardness and fracture toughness was observed for the coatings made from duplex cobalt coated powders with near-nanocrystalline WC grains and with feedstock powder size of 45-60μm, which can be beneficial for high performance and longer tool life.
مولانا قاضی اطہر مبار کپوری گذشتہ مہینہ سفر میں جب مولانا قاضی اطہر مبار کپوری کے انتقال کی خبر ملی تو بڑا دھکا لگا، مجھے ان کی تجہیز و تکفین میں شرکت سے محرومی کا ہمیشہ بہت ملال رہے گا۔ اعظم گڑھ کے متعدد علماء کو بین الاقوامی شہرت نصیب ہوئی خود مبارکپور کے جو اعظم گڑھ کا مشہور قصبہ اور علم و تعلیم اور صنعت و حرفت کا بڑا مرکز ہے، مولانا عبدالرحمن مبارکپوری صاحب تحفۃ الاحوذی اور مولانا عبیداﷲ رحمانی شارح مشکوٰۃ المصابیح کا آوازہ شہرت عالم اسلام میں بلند ہے، انہی لوگوں کی صف میں مولانا قاضی اطہر مبارکپوری نے بھی اپنی جگہ بنالی تھی، مگر افسوس کہ دست اجل نے انہیں ہم سے چھین لیا، یہ بڑا علمی سانحہ ہے اور قاضی صاحب کا خلا پر ہونا آسان نہیں۔ ان کی ولادت ۱۹۱۶ء میں ہوئی، ان کے نانا مولانا احمد حسین رسولپوری عربی زبان و ادب کے ماہر اور صاحب تصانیف کثیرہ تھے، قاضی صاحب نے ان کا عربی دیوان مرتب کر کے شائع کیا تھا، انہوں نے عرصہ دراز تک ڈھاکہ میں مسند درس کو رونق بخشی۔ انہی سے قاضی صاحب نے عربی کی ابتدائی کتابیں پڑھیں تھیں پھر مبارکپور کے مشہور مدرسہ جامعہ احیاء العلوم میں درسیات کی تکمیل کی اور جامعہ قاسمیہ مراد آباد میں مولانا فخرالدین، مولانا سید محمد میاں اور مولانا سید اسماعیل سنبھلی سے صحاح ستہ کا درس لیا۔ طالب علمی کے زمانے میں ان کو شعر و سخن سے دلچسپی تھی، اور خود بھی سخن فرماتے تھے، یہ تحریک آزادی کے شباب کا زمانہ تھا، قاضی صاحب کو سیاست اور ہنگامہ آرا قومی جدوجہد سے کبھی سرو کار نہیں رہا، تاہم آزادی کا جادو ہر شخص پر چل گیا تھا، قاضی صاحب بھی اس سے متاثر ہوئے بغیر نہیں رہ سکے، مبارکپور میں ہر قسم کے...
Dispensation of justice is a prerequisite for any society to move forward. The concept of justice encompasses whole spheres of life. The judicial system of Islam is based on a very strong footing. According to the Sharia, testimony is one means of proof. One aspect of it is 'evidence of woman' which has been discussed by the jurists in detail. According to the majority opinion, evidence of women is acceptable only in civil cases and Ta'azirat. , while it is not acceptable for the punishment of Hudood and Qisas. They have based their opinion on some verses of the Holy Quran and the Traditions, while there is a strong opinion of some other jurists that there is no restriction on the evidence of women in all kinds of cases. This article deals with the issue in which different opinions of the jurists have been presented with their arguments
Most of the farmers of irrigated areas cultivate their fields with traditional tillage practices which increase the cost of production as well as delaying sowing which has adverse effects on crop growth and yield. In addition towards tillage, straw managing is a key factor for better crop growth and yield. Two field trials were conducted to estimate the “Crop residual management techniques with different tillage practices in a rice-wheat cropping system” at the Post Graduate Agricultural Research Station (PARS), University of Agriculture, Faisalabad during 2007-08 and 2008-09. Both the experiments were laid out on a randomized complete block design (RCBD) with split plot arrangement using four replications, in a net plot size of 10 m x 20 m. In the first experiment three tillage systems (conventional tillage, minimum tillage and zero tillage) were used in sub plots and straw management (removal of rice straw and burning of rice straw) in main plot was applied. Tillage systems significantly influenced soil physical properties, growth and yield characteristics as well as wheat yield. Reducing tillage improved soil structure and increased soil bulk density which led to higher crop yield. Happy seeder plots produced higher yield and yield components in comparison with other tillage systems. Wheat yield with happy seeder plots were 18% and 15 % higher than minimum and conventionally tilled plots respectively. Generally, differences between removal of rice straw and burning of rice straw were more pronounced; removal of rice straw had positive influence on growth, yield components, yield and grain quality. Increased grain weight per spike, 1000-grain weight and grain yield were recorded with burning of rice straw. Wheat yield with removal of rice straw was 17.5% and 14.55% higher than burning of rice straw respectively. The happy seeder yield was 5.2 t/ ha -1 which was higher in comparison with other tillage practices. Zero tillage showed positive association with protein contents but negative association with carbohydrate contents. Zero tillage was found best among all other tillage practices in rice-wheat cropping system of Faisalabad, Punjab, Pakistan.