The dissertation deals with the investigation of magnetic field effect on plasma parameters and surface structuring of two metallic alloys (Cu & Mg) after laser irradiation. The plasma parameters are evaluated by using Laser Induced Breakdown Spectroscopy (LIBS) technique, whereas, micro/nano structuring of metallic alloys is explored by Scanning Electron Microscopy (SEM) analysis. This dissertation consists of following two parts. In part (A) the effect of magnetic field on ns-LIBS analysis and surface modifications of both metallic alloys has been investigated. Part (A) is further divided into sections. In section I, the effect of laser irradiance on metallic alloys plasma is exposed in the presence and absence of Transverse Magnetic Field (TMF) while keeping the pressure of environmental gases constant i.e. 5 Torr. For this purpose both metallic alloys were exposed to Nd: YAG laser (1064 nm, 10 ns) pulsed energies ranging from 25 mJ to 200 mJ. Cu-alloy is exposed at various ns laser irradiances ranging from 1.9 GW/cm2 to 5 GW/cm2, whereas, for Mg alloy irradiances are ranging from 0.3 GW/cm2 to 2.6 GW/cm2 under Argon (Ar), Neon (Ne), and Helium (He). Section II of this part deals with the investigation of different pressures of environmental gases with & without magnetic field by keeping irradiance constant. For this purpose time integrated Laser Produced Plasma (LPP) parameters of metallic alloys evaluated under Ar, Ne and He environments at different pressures ranging from 1 Torr to 100 Torr at constant irradiance of 4.4 GW/cm2 (Cu-alloy) and 2 GW/cm2 (Mg-alloy) and at constant time delay of 1.25 µs have been explored. The values of excitation temperature (Texc) and electron number density (ne) of LPP of metallic alloys are higher in the presence of 1.1 Tesla magnetic field as compared to field free case. Both Cu & Mg alloys show similar trends for used range of ns laser irradiances in the presence of Ar, Ne & He. It is also found that trends of both excitation temperature and electron number density are increasing with increasing laser irradiances from 1.9 GW/cm2 to 4.4 GW/cm2 for Cu-alloy & from 0.3 GW/cm2 to 2 GW/cm2 for Mg-alloy. For the highest used irradiance for both metallic alloys the decrease in both parameters is observed. In the case of pressure variation an increase in both plasma parameters is observed by increasing pressure from 1 Torr to 5 Torr at fixed irradiance of 4.4 GW/cm2 & 2 GW/cm2 for Cu-alloy and Mg-alloy respectively. A decrease in LPP parameters by increasing pressure from 5 Torr to 100 Torr for both metallic alloys is observed. The magnetic confinement validity is confirmed by analytically evaluating thermal beta (βt), directional beta (βd), confinement radius (Rb) and diffusion time (td) for LPP of both Cu and Mg-alloys. Surface modifications of laser ablated Cu & Mg alloys is performed by Scanning Electron Microscope (SEM) analysis. The formation of less distinct surface structures are observed on Cu-alloy in the presence of TMF as compared to field free case. Whereas, for Mg-alloy distinct and well-defined structuring is observed with TMF as compared to absence of field. In order to investigate the effect of femtosecond laser irradiation effects on plasma parameters and surface modifications, part (B) is performed. In part (B), the effect of magnetic field on fs-LIBS analysis and surface modifications of both metallic alloys has been investigated. Femto second pulses of Ti: Sapphire laser system (800 nm, 35 fs, 1 KHz) are employed as source of irradiation. Part (B) is further divided into sections. Section I, deals with measurements performed at various irradiances ranging from 0.011 PW/cm2 to 0.117 PW/cm2 for Cu-alloy and irradiances ranging from 0.0052 PW/cm2 to 0.0526 PW/cm2 for Mg alloy under fixed 15 torr pressure of Ar and Ne with & without TMF. This section also deals with exploring the effect of different pressures of Ar ranging from 1 Torr to 35 Torr with & without TMF at fixed irradiance of 0.082 PW/cm2 & 0.043 PW/cm2 for Cu-alloy and Mg-alloy respectively. For fs-LIBS analysis the same trends of Texc and ne are observed as have been observed for ns-LIBS for both metallic alloys for irradiance variation as well as pressure variation. In order to confirm the validity of magnetic confinement for fs- LIBS analysis. The values of βt, βd, Rb and td are also evaluated.To correlate the LPP parameters of metallic alloys with surface modifications Field Emission Scanning Electron Microscope (FE-SEM) analysis is performed. It reveals the formation of Laser Induced Periodic Surface Structures (LIPSSs). These LIPSSs are of two kinds LSFL (Low-spatial-frequency LIPSSs) and HSFL (High-spatial-frequency LIPSSs) along agglomers and nano rims which are not formed in case of ns-laser ablation. For both metallic alloys distinct and well-defined surface structuring is observed in the presence of the field as compared to absence of field.The comparison is made between ns-LIBS and fs-LIBS analyses. It is observed that both LPP parameters i.e. Texc and ne for both metallic alloys are higher for ns-LIBS as compared to fs-LIBS. It is also revealed that ns laser irradiation is responsible for micro scale surface structuring, whereas, in case of fs laser ablation nano scale well defined LIPSSs are formed. When comparison is made between Cu-alloy and Mg-alloy, it is observed that higher excitation temperature is associated with Mg-alloy plasma whereas, electron number density for Cu-alloy plasma is greater for both ns and fs laser. It is also revealed that both excitation temperature and electron number density play a substantial part for the growth of surface structures on both metallic alloys. It is concluded that by applying external magnetic field during laser irradiation, controlled material surface structuring is possible for applications such as formation of gratings and field emitters where spatial uniformity is critically important.
عبداﷲ یوسف علی افسوس ہے کہ پچھلے دنوں ہماری گزشتہ قومی زندگی کاایک اورستون گر گیا یعنی مسڑعبداﷲ یوسف علی نے لندن میں وفات پائی۔مرحوم انگریزی زبان کے نامور انشا پرداز، مشہور ماہر ِتعلیم اور متعدد بلند پایہ کتابوں کے نامور مصنف تھے۔ انڈین سول سروس سے الگ ہونے کے بعد وہ دومرتبہ اسلامیہ کالج لاہور کے پرنسپل ہوئے اوریہیں ان کے دل ودماغ میں یکایک ایک عجیب مذہبی اوردینی انقلاب ہوا۔جس کے باعث انہوں نے قرآن مجید کاانگریزی ترجمہ کرنا شروع کر دیا۔ترجمہ کی زبان کس قدراعلیٰ اوربلندپایہ ہے اس کی دادوہی دیں گے جن کو انگریزی زبان وادب کا ذوق ہے اورجو مختلف اسالیب کی باریکیوں سے واقف ہیں۔ترجمہ کے علاوہ جگہ جگہ تفسیری نوٹ بھی بڑے فاضلانہ اورعالمانہ ہیں اور سب سے بڑی بات یہ ہے کہ چوں کہ مرحوم نے ترجمہ کے وقت حضرت شاہ عبدالقادر دہلویؒ کے اردو ترجمہ قرآن کوخاص طورپر پیش نظر رکھا تھا اس بنا پر اب تک انگریزی میں جتنے بھی تراجم شائع ہوچکے ہیں صحت عقائد کے لحاظ سے صرف مرحوم کاہی ایک ترجمہ ان سب میں ایسا ہے جس پر اعتماد کیا جاسکتا ہے۔ مرحوم کو درحقیقت قرآن مجید کے ساتھ عشق ساہوگیاتھا اوراسی کااثر تھاکہ وہ اسی زمانہ میں حرمین شریفین کی زیارت اورحج بیت اﷲ کی سعادت وشرف سے بہرہ یاب ہوئے۔واپسی پر جب کبھی وہ سرپرعقال اوربدن پرجُبہ وعبا کے ساتھ نظر آتے تھے توبڑے بھلے لگتے تھے۔اسلامیہ کالج کے طلبا کونماز کی اوردیگر شعائر اسلامی کی پابندی واحترام کی بڑی تاکید کرتے رہتے تھے۔جمعہ کی نماز کالج کی مسجد میں کبھی کبھی خود بھی پڑھاتے تھے، ورنہ نماز سے پہلے یانماز کے بعد وعظ تو اکثر ہی کہتے تھے۔عادات واخلاق کے لحاظ سے بڑے خلیق وملنسار مگر حددرجہ باحمیت وخودداراورہمدرد وغم گسارتھے۔ضابطہ پسندی اوراصول پروری ان کی فطرت تھی۔حق تعالیٰ مغفرت وبخشش...
Issues of inheritance have been thoroughly maintained in the Holy Quran and Sunnah. As per these injunctions, the principle of AL’Aqrab fal’aqrab “the closest in kin” is to be observed. According to these principles, grandchildren, even though orphaned, have no right to inherit grandfather in the presence of direct children. On the other hand, section 4 of Muslim Family Laws, 1961 grants a share to orphaned grandchildren from the inheritance of his grandfather. Whereas, as per the constitution, no law can be enacted which is repugnant to the injunctions of the Holy Quran and Sunnah, now, whether the above mentioned section is in conformity with the injunctions of the Holy Quran and Sunnah or not is to be treated properly. If not, so from which perspective, it is repugnant to the Islamic Injunctions? These questions have been analysed critically in this paper and finally it has been concluded that section 4 of Muslim Family Laws Ordinance, 1961 contrasts with the injunctions as laid down in the Holy Quran and Sunnah.
Contamination of soils by heavy metals is of widespread occurrence as a result of human activities. Among heavy metals, lead (Pb) is a potential pollutant that accumulates in soils, water, crops and atmosphere. Lead is not required for any known biological function but it is absorbed by crop plants and gets way into human food chain. There are few examples of genetic differences being exploited to produce low Pb containing rice through decreased metal uptake in Pb-contaminated areas. In normal and salt-affected soils, a very few efforts had been previously done to explore the growth and physiological responses of rice to Pb and inorganic amendments including calcium (Ca), sulphur (S) or phosphorous (P) based compounds. For these reasons, a research project with a series of experiments was carried out at University of Agriculture, Faisalabad, Pakistan and at Ghent University, Belgium. The first study was carried out to evaluate the variations among fourteen rice genotypes for Pb tolerance, accumulation and translocation in hydroponics, at different applied Pb salts i.e., PbCl2, PbSO4 and Pb(NO3)2 with their increasing application rates (0, 100 and 200 μM). The results showed that the Pb bioavailability/phyto-toxicity to rice was greater when Pb was applied as Pb(NO3)2 followed by PbCl2 and PbSO4. It was evident that Shaheen basmati and KS-282 rice varieties can be a wise choice in low to moderately Pbcontaminated areas for safe rice production. The second study was undertaken to investigate the effect of foliar applied Pb at 25 mg L-1 as PbCl2 and Pb(NO3)2 along with an uncontaminated control, for Pb tolerance, accumulation and translocation of rice genotypes. The results showed that the rice varieties had significant variations for Pb tolerance, absorption and translocation. Shaheen basmati and KS-282 rice varieties were proved to be Pb-tolerant. The foliar application of Pb(NO3)2 had more devastating effect than PbCl2. Salinity and heavy metals (e.g., Pb) can occur simultaneously in soil and water. Therefore, the differential growth and physiological responses of two rice varieties (Shaheen basmati and KS-282) were evaluated in normal and salt-affected Pb-contaminated soils in a pot study. The results showed that growth, yield and physiological indices of rice decreased with increasing rates of Pb (0, 50, 100 and 150 mg kg-1 soil) in both rice varieties in normal and salt-affected soils. The Pb concentration, uptake and translocation in rice increased with a gradual increase in soil applied Pb. At a certain defined rate of Pb (0, 50, 100 or 150 mg kgxxiii 1 soil), the concentration, uptake and translocation of Pb in rice straw and paddy was found significantly (p ≤ 0.05) higher in salt-affected soil than normal soil. The higher growth, yield, physiological features, lower Pb concentration, uptake and translocation were found in Shaheen basmati than KS-282, at all rates of applied Pb, in both types of soils. Chemical immobilization of Pb with soil-applied inorganic amendments seems very important for Pb-contaminated soils. A pot study was conducted to evaluate the effectiveness of inorganic amendments at different rates of application for the immobilization/remediation of Pb in normal and salt-affected soils. There were three amendments with different rates viz. gypsum (3, 6 and 9 me Ca 100g-1 soil), rock phosphate i.e., RP (3, 6 and 9 me Ca/P 100g-1 soil) and di-ammonium phosphate i.e., DAP (20 and 40 % higher P than the recommended P as DAP fertilizer). Shaheen basmati was grown in spiked soil with Pb at 100 mg kg-1. The results showed that the reduction in rice growth, yield and physiological attributes were more pronounced in salt-affected Pb-contaminated soil than normal Pb-contaminated soil. The decrease in rice growth, yield and physiological features were counteracted by the applied gypsum, RP and DAP amendments. Gypsum application at 9 me Ca 100g-1 soil was proved the most efficient in improving rice growth and yield, and reducing Pb concentration, accumulation and translocation in the normal and salt-affected Pb-contaminated soils. Total heavy metal contents provide little information on the bioavailability of the heavy metals. Understanding the mobility of Pb in the soil and its chemical speciation in the soil solution is of great importance for accurately assessing environmental risks posed by Pb. Therefore, an incubation study was conducted to explore the effect of amendments (gypsum, RP and DAP) under different soil moisture regimes i.e., flooding regime (FR) and 75 % field capacity (FC) and incubation time on Pb mobility and chemical speciation in normal and saltaffected Pb-contaminated paddy soils. The results showed that after 110 days of incubation, the concentration of Pb in pore water was more in soils at 75 % FC than FR. Gypsum remained more effective in reducing Pb bioavailability followed by DAP and RP. After 2 and 30 days of applied treatments, Pb species were estimated by using geochemical modeling software Visual MINTEQ version 3.0. Among these species, free Pb2+ was found more in Pb-contaminated soils, while PbCl+ was pronounced in salt-affected soils. Whereas, gypsum increased Pb(SO4)2 2-, while DAP and RP enhanced the PbH2PO4 + species formation and decreased free Pb2+ in pore water, thereby reduced the availability of Pb.