Numerical simulation of incompressible laminar flows of Newtonian and non–Newtonian Fluids is studied.For non–Newtonian fluids, a shear thinning Power law model is employed. The problem attempted in the study is a two–dimensional 1:4sudden expansions as well as 4:1 contraction channels in Cartesian coordinates.Axisymmetric pipe geometry in cylindrical polar coordinates is moreover considered. All domains may be filled with porous matrix or in absence of Porous Media.For two–dimensional model,the basic governing system of equations covers the equation of continuity and Darcy–Brinkman momentum equation.For well posed problems suitable initial and boundary conditions are adopted. A numerical formulationapplied in the existing investigation is based upon the time–dependent finite element scheme.Applied numerical method is so called Taylor–Galerkin/pressure–correction algorithm. Algorithm is design in such a way that, time derivative is discretised in two steps. At first step, forward difference is used at half time step. While, for full time step, a central difference scheme is adopted, to make the scheme second order accurate. Pressure is dealt with projection method introducedCrank–Nicolson choice (Ɵ = 0.5) and on diffusion term implicitness is applied to form a semi–implicit scheme. Adopting time marching scheme steady solutionsare sought to investigate various flow features. In both expansion and contraction flows, main interesting phenomena is development of vortices at different places, vortex enhancement and excess pressure drop. Other motivated features of the problem are the effects of fluid inertia on recirculation flow rate, size in terms of length and intensity, and location of vortices. For excess pressure drop,Couette–Correction is also inspired phenomena.For non–Newtonian fluids, investigation of shear–thinning effects is besides very important flow feature. In expansion flows in absence of porous material, at two different locations vortices develops, such as, the silent corner and the lip of expansion channel.For Newtonian flow, these vortices grow with increasing inertia. While, further increasing inertia progressively these vortices enriched and merge a centre of both eddies is observed. Furthermore, at high value of inertia vortex augmentation in the downstream is perceived. Regarding vortex size in terms of vortex intensity and length correspondingly growth with increase in inertial values is witnessed. Regarding pressure drop, the Couette–Correction decline linearly up to Re = 05, while, after this stage the Couette–Correction enhances linearly with increasing inertia. Whereas, in the presence of porous space in expansion flows, all flow features diminish such as, vortex enhancement, vortex length and intensity. No evidence of vortex development has been detected even at high inertial values and changing permeability of porous material. The Couette–Correction remains static with increasing inertia in porous matrix. In contraction channel, initially, at low inertial value in salient corner a small vortex is observed. With increasing inertial values this initial small vortex diminishes. Fluid inertia pushes the fluid towards contraction wall and reduces the size of eddy. The Couette–Correction enhances linearly with increasing inertia. While, with the introduction of porous material no evidence of vortex is admitted even with changing permeability/porosity. However, the Couette–Correction persist static with increasing inertia. For the simulation of axisymmetric 1:4 expansion tube, the flow of Newtonian fluids has been investigated. Initially, a small vortex develops in the silent corner at low value of inertia (Re=1). Subsequently, with increasing fluid inertia the vortex enhancement is observed. Both vortex intensity and length, initially, increase linearly. However, at high level of fluid inertia these quantities increase in non–linear fashion and Couette–Correction decrease in asymptoticshape. With the introduction of porous space, no vortex activity is detected and Couette–Correction remains stationary. For shear–thinning non–Newtonian fluids, adopting the Power law model at various indices, flow through axisymmetric pipe has been analysed. At high value of Power law index close to Newtonian fluid, with increasing inertia recirculation flow rate of fluid is observed in non–linear tendency. While, at low value of Power law index tendency of vortex development has been changed and eddy size remain steady. And Couette–Correction decreases asymptotically. In the presence of porous material, no movement of recirculation is found and Couette–Correction remains stationary. The excellent agreement of numerical predictions is attended based upon the employed finite element algorithm against other experimental as well as numerical solution.
طاہر نظامی(۱۹۵۰ء۔پ) طاہرؔ تخلص کرتے ہیں۔ آپ پسرور میں پیدا ہوئے۔ آپ معروف شاعر خدا بخش مضطرؔنظامی کے بیٹے ہیں۔۱۹۸۲ء میں رائٹرز فورم سیالکوٹ نے آپ کو بہترین شاعر قرار دیا۔ (۱۱۳۱) آپ کی پہلی غزل ماہنامہ ’’حرم‘‘ لاہور میں اور پہلی نظم ’’اردو زبان‘‘ سرگودھا میں شائع ہوئی۔ طاہر کا شعری کلام ’’فنون‘‘،’’اوراق‘‘،’’ادبی دنیا‘‘ ،’’ادبِ لطیف‘‘،’’نیرنگ خیال‘‘،’’نیا دور‘ ‘،’’الفاظ‘‘ ،’’نقش‘‘ اور تحریریں میں شائع ہو چکا ہے۔ ’’بلا جواز‘‘ طاہر کا ایک غیر مطبوعہ شعری مجموعہ ہے۔ زیر ترتیب نمونہ کلام ملاحظہ فرمائیے:
In the Holy Quran, Allah has mentioned many such social rules that are very important for the peace & stability of a society and welfare of human beings. This article will not only highlight the word “La'allakum” in terms of meaning, diction and eloquence but also explain its usage for different purposes. Apart from this, in this article light will be thrown on such social rules that have been defined under the word “La'allakum" along with its philosophy and their implementations in the present era.
Field and laboratory experiments were conducted to see the effect of neem (Azadirachta indica A. Juss) oil at 1, 2% and neem seed water extract at 2, 4% alone, in combination with bio-control agents (Trichogramma chilonis and Chrysoperla carnea) with that of synthetic chemicals viz. Actara 24WG (60gmha-1), Imidacloprid 25%WP (625 gmha-1), Fenpropathrin 20EC (750mLha-1), Polytrin-C 440EC (1250mLha-1) and proclaim 19EC (500mLha-1) against sucking insects i.e. whitefly (Bemisia tabaci Genn.), Jassid (Emrosca devastans Dist.), thrips (Thrips tabaci Lind,) and chewing insects i.e. spotted bollworm (Earias insulana Boisd.), american bollworm (Helicoverpa armigera Hubner) and pink bollworm (Pectinophora gossypiella Saund.) of cotton (CIM-499). Crop was sprayed 5 times during the cotton season. First spray was carried out 45 days after the date of sowing of crop and repeated at an interval of 15 days of first spray and so on. Data of population dynamics of sucking insects were recorded 24 hours before and then, 24, 168 and 336 hours after each spray. The data for American and spotted bollworms infestation were recorded 168 and 336 hours after each spray while for Pectinophora gossypiella, the bolls were collected on 15th of August, 14th September and 15th October 2005 and 2006 and dissected in the Laboratory to calculate the infestation. For the yield of seed cotton, the picking was started when 50 % bolls were open/ready for picking and was continued up to end of crop. Overall, after synthetic insecticides, neem oil 2%+bio-control agents (Trichogramma chilonis and Chrysoperla carnea) reduced significantly (p<0.05) % population of sucking insects (thrips. whitefly and jassid) and % infestation of bollworms (American and spotted) of cotton (168 hours after each spray). In case of pink bollworm, the bolls collected on 15th August, 15th September and 15th October, effect of treatmentsand time period/observations were found significant (p<0.05) on % damage/infestation of pink bollworm.The lowest mean % damage (5.00%) recoded in the treatment treated with insecticides followed by N2+B (8.89 %), N1+B (10%) and W4+B (11.11%) which performed similar while the highest mean % damage recorded in W2 with 22.78 % and N1 with 21.11 % which performed similar compared with control (25.56%). Neem oil 2 % (14.44 %) and W4 (17.18%) gave similar results. Best results were received from the bolls collected during 15th August (8.83%) damage. Maximum yield of seed cotton (1494 kg) was received in the plot treated with N2+B after insecticide (1895 kg). Neem derivatives at all tested concentrations have significant negative effect on settling response of whitefly and jassid on cotton leaves as compare with that in their respective control (untreated). Significantly lower numbers of test insects settled on neem derivatives treated leaves except N1 and W2 in spotted bollworm as compare with that in their respective control. Intensity of numbers of test insects settled on neem derivatives was lower at higher concentrations of neem derivatives due to repellent/deterrent effect of neem derivatives. Neem derivatives at all concentrations affected development (larvaeandpupae) of spotted bollworm. Significantly minimum survival of larvae and maximum larval mortality and less pupal formation was observed in Fenpropathrin 20EC application due to its toxic effect while neem derivatives at higher concentration also affected survival of larvae and resulted into larval mortality due to toxic effect of neem derivatives. Pupal formation was affected at higher tested concentrations of neem derivatives due to growth regulating effect of neem derivatives. Adult formation was not significantly affected by any treatment. The longest larval and pupal duration were observed at higher concentrations of neem derivatives due to growth regulating effect of neem derivatives. In laboratory trials, all the neem derivatives (indirect effect) had non-significant differences on the parasitism by Trichogramma chilonis on Helicoverpa eggs. Though, in the N2 treatment, % parasitization was significantly lower (P<0.05) than % parasitization in W2 treatment (indirect and direct effect). Adult emergence of T. chilonis was not affected by the concentrations of neem derivatives. Percent parasitization of Helicoverpa eggs by T. chilonis were inhibited (indirectand direct effect) in treatment of Proclaim 19EC (Insecticide) along with adult emergence too due to toxic effect of Proclaim 19EC. Neem derivatives at different concentrations and insecticide have significantly altered feeding/consumption ability of predator (p<0.05). The highest % consumption of aphids by Chrysoperla carnea was observed in the treatments of low concentrations of neem derivatives while the lowest % consumption of aphids was noted in the treatments in insecticide and higher concentrations of neem derivatives. Aphid % consumption by Chrysoperla carnea at different prey (aphids) densities were significantly different (p<0.05). Percent consumption of 75.87% was recorded when offered 16 aphids day-1 to predator. No significant differences were observed in % consumption when offered 32, 48, 64 and 80 aphids day-1 to predator. Effect of treatments (neem derivatives at different concentrations and insecticide) and different instars of Chrysoperlacarnea were found significant (P<0.05) on % consumption/feeding of aphids. The highest reduction in prey % consumption rate by Chrysoperla carnea was observed in Imidacloprid 25%WP application (31.77%) followed by N2(69.19%) and W4 (70.61%) while the lowest reduction in prey % consumption rate by Chrysoperla carnea was observed in the treatment of N1 (91.77%) and W2 (91.44%) as compared with control (94.94%). The highest % consumption of aphids was observed by the 2nd instar larvae (75.94%) followed by 1st instar (74.82%) of Chrysoperla carnea.