The effects of change in fuel density, change in clad material and change in fuel material on the inherent safety features of a typical material test reactor were analyzed. The International Atomic Energy Agency’s 10 MW benchmark reactor was selected for the study. Standard computer codes WIMS-D4 and CITATION were used to perform neutronics calculations while PARET was used to carryout the steady state and transient thermal hydraulic analysis. In all, seven thermal hydraulic simulations were performed for each configuration. They were the steady state analysis, four controlled transients i.e. fast reactivity insertion, slow reactivity insertion, fast loss of flow and slow loss of flow transients, and two uncontrolled reactivity insertion transients, i.e. small reactivity insertion and large reactivity insertion transients. Two families of the high density dispersion fuels were analyzed to see the effect of changed uranium density on the inherent safety features of the reactor. These families were U 3 Si 2 -Al (having uranium densities of 4.10, 4.80 and 5.66 g/cm 3 ) on the lower side and U9Mo-Al (having uranium densities of 6.57, 7.74 and 8.90 g/cm 3 ) on the upper side. It was observed that the steady state thermodynamic behaviour of all the fuels was same, only the fuel temperatures of U 3 Si 2 -Al fuels showed some differences. During the fast reactivity insertion transient, the maximum reactor power achieved increased by about 29% for U 3 Si 2 fuel-family while the increase was 45% for U9Mo fuel-family. This resulted in increased maximum temperatures of fuel, clad and coolant outlet, achieved during the transient. This increase for U 3 Si 2 fuels was 32 K, 21.1 K and 5.1 K respectively, while for U9Mo fuels it was 27.7 K, 19.7 K and 7.9 K respectively for maximum fuel, clad and coolant outlet temperatures. During the slow reactivity insertion and loss of flow transients, no appreciable difference in the reactor power and temperature profiles was observed. For small reactivity insertion transient, the new power level increased as uranium density increased. The increase was 8.1% for U 3 Si 2 fuel-family while it was 5.8% for U9Mo fuel-family. In uncontrolled large reactivity insertion transient, the feedback reactivities were unable to control the reactor which resulted in the coolant boiling; the one with the highest fuel density was the first to reach the ONB. xxviiIn order to see the effects of different fuel materials, the original aluminide (UAl x -Al) fuel of the reactor was replaced with silicide (U 3 Si-Al and U 3 Si 2 -Al) and oxide (U 3 O 8 -Al) dispersion fuels having the same uranium density of 4.40 g/cm 3 as of the original fuel. The oxide fuel had higher fuel temperatures during steady state and transients. During fast reactivity insertion transient, the maximum power reached for oxide fuel was 0.35 MW lesser than that of aluminide fuel, but its maximum fuel temperature was 13 K higher. With respect to the UAl x -Al fuel, the maximum powers of U 3 Si-Al and U 3 Si 2 -Al fuels were higher by 2.11 MW and 1.82 MW respectively, while the maximum fuel temperatures were lower by 5.7 K and 4.5 K respectively. During slow reactivity insertion and loss of flow transients, the power and temperature profiles of all the fuels were almost the same only fuel temperatures varying; the maximum fuel temperature of the oxide fuel being 8 K to 12 K higher than that of the other fuels. During uncontrolled small reactivity insertion transient, the maximum fuel temperature attained by the oxide fuel was almost 16 K higher than that of the others at the new steady state. During uncontrolled large reactivity insertion transient, the coolant of oxide fuel was the last to reach the ONB but again at the cost of higher fuel temperature. In order to see the effects of different clad materials, only the Al clad and side plates of the reactor fuel were replaced by stainless steel (clad of a fast reactor) and zircaloy-4 (clad of a PWR). The zircaloy-4 clad gave a positive clad temperature feedback coefficient. The very high absorption cross section of stainless steel made it a very unlikely choice for clad material. Out of the remaining two, the main difference was in the fuel temperatures with zircaloy-4 cladded fuel having higher fuel temperatures. The temperature of zircaloy-4 cladded fuel was 20 K to 40 K higher than that of Al cladded fuel during different transients.
جنگل جنگل کہانیوں اورنظموں کامجموعہ ہے،جسے ڈاکٹرمحبوب حسن نے تحریر کیاہے،محبوب حسن اردو ادب میں ایک جاناپہچانانام ہے،مختلف موضوعات پران کی پانچ کتابیں منظرعام پر آچکی ہیں،ٹنڈے کباب ان کی طنزومزاح کی کتاب ہے جسے علمی و ادبی حلقے میں کافی پذیرائی ملی ہے،دیگر اصناف کی طرح ادب اطفال پر بھی وہ مستقل لکھتے رہتے ہیں،بچوں کے لیے سبق آموز،اخلاقی اوراصلاحی کہانیاں ان کے فکری اورتخلیقی رجحان کا پتہ دیتی ہیں، جنگل جنگل ادب اطفال پر ان کی دوسری کتاب ہے،اس میں پانچ کہانیاں اورچودہ نظمیں ہیں،بچوں کی نفسیات اوران کی ذہنی سطح کو مدنظر رکھتے ہوئے انہوں نے یہ کہانیاں لکھی ہیں،اس کتاب کی ایک خصوصیت یہ بھی ہے کہ اس میں ماحولیات کو سامنے رکھ کرکہانیاں تخلیق کی گئی ہیں،اس طرح کی کہانیاں لکھناوقت کا تقاضا ہے،تاکہ بچے ماحولیات پیڑ،پودے،بادل اورپہاڑ وغیرہ سے مانوس ہوں،اورموبائل کی دنیاسے باہرنکل کران کے متعلق بھی سوچ سکیں،ماحولیات سے بچوں کو واقف کرانابہت ضروری ہے،تاکہ وہ اس کے فائدے کو سمجھ سکیں،مصنف مقدمہ میں لکھتے ہیں‘‘ہمارے ادیب وشاعر سائنسی اورماحولیاتی موضوعات پرمشتمل نظمیں اورکہانیاں تخلیق کررہے ہیں،میری یہ تخلیقی کاوش اسی سلسلے کی ایک کڑی ہے،اس کتاب میں نظمیں اورکہانیاں دونوں کے نمونے شامل ہیں،اس انتخاب میں شامل تمام کہانیاں اورنظمیں ماحولیات سے متعلق ہیں،ان تخلیقات میں جنگل،آبشار،پیڑ،پہاڑ،بادل،بارش،ہاتھی،خرگوش،بلی،بندر،مچھلی، مینڈک،ندی جیسے خالص ماحولیاتی موضوعات پیش کیے گئے ہیں’’۔ جنگل جنگل میں ایسی کہانیاں ہیں جسے ہم نے پہلے سن رکھی ہیں ،یا نصابی کتابوں میں پڑھ رکھی ہیں،مصنف نے انہی کہانیوں کو نئے الفاظ و انداز میں پیش کیاہے،ہاں یہ بات اپنی جگہ طے ہے کہ بچے ان کہانیوں کو ضرور پسندکریں گے اور ان سے لطف اندوزہوں گے،‘‘کہانی جنگل کی’’اس مجموعے کی پہلی کہانی ہے،اس میں شیخو نامی خرگوش اوربھولاچوہا کی کہانی بیان کی گئی ہے،شیخوجیساکہ نام سے ہی ظاہرہے بہت شیخی بگھارتاتھا،اسے اپنی خوب صورتی پر بہت غرورتھا،...
The enormous development in the telecommunications and media technology reduced disparities between time and space, in the age of the Internet and social networking it shaped an electronic community in the form of a real community. So, if dialogue is a religious principle then interaction and mutual understanding between nations and peoples is considered a goal in Islam, since God's wisdom in His creation that people are different, therefore sacred texts came encourage such interaction. Communication and interaction between peoples is an authentic human tendency, a continuous cultural movement and an effective mean of social coexistence, that strengthening the bonds of rapprochement and mutual understanding between human beings, that is why social communication is usually known as the mutual interaction between individuals, this interaction is a type of social networking through the media and various communication that develop and deepening the social connections.
In present climate scenario, water shortage is extensively damaging the grain harvest from rice fields. Paddy has semiaquatic ancestors, so it is sensitive to agricultural drought. Aridity targets the morphological, biochemical, physiological and molecular features of it. An integrated strategy is required to save rice cultivation under frequent drought stress. In the following study, four interlinked approaches have been practiced to secure rice cultivation in a dry environment. In the first experiment, diversified rice germplasm was screened at seedling stage to select 20 drought responsive genotypes including 10 drought tolerant, five moderately drought tolerant and five drought susceptible. These genotypes were selected on the basis of gain in root length, shoot length, fresh root weight, fresh shoot weight, dry root weight and dry shoot weight. Selected genotypes were further tested at germination, seedling and maturity stages to trace a marker-trait that could rapidly label drought responsive genotypes and to check the efficiency of the first experiment of germplasm screening. At germination stage, imbibition rate, the speed of germination, radical and plumule length, radical and plumule weight, proline contents, total antioxidant capacity and malondialdehyde concentration were determined from germination seeds. At seedling stage root length, shoot length, fresh root weight, fresh shoot weight, dry root weight, dry shoot weight, proline contents, total antioxidant capacity and malondialdehyde concentration were determined from the leaves. At maturity stage, the number of tillers, plant total biomass, fertile florets, 100-grain weight, proline contents, total antioxidant capacity and malondialdehyde concentration were determined from the leaves. It was observed that screening at germination stage by using proline and TAC as markers is as reliable as screening at seedling and maturity stages. The expression pattern of OsP5CS gene at germination, seedling and maturity times has confirmed the reliability of proline for screening rice germplasm at different growth stages. It was concluded that rice seed banks keep extensive genetic variability for the climate-smart breeding programs. Determination of proline and TAC from germinating seeds can speed up the process of germplasm phenotyping against drought stress. In the second experiment, selected genotypes were tested for their association with eco-contributors (Piriformospora indica, zinc, calcium and molybdenum) under optimum and deficient water supply. Genotypes were supported with P. indica and grown under control and drought environments in Zn, Ca and Mo deficient nutrition media. Factorial under CRD with three replications was performed for the completion of the experiment. Plants were evaluated on the basis of root length, shoot length, fresh root weight, fresh shoot weight, dry root weight, dry shoot weight, the concentration of phosphorus, calcium and zinc, proline contents, total antioxidant capacity and malondialdehyde concentration. Significant improvement was recorded when plants were inoculated with P. indica and maximum damage was recorded when plants were in Zn deficient environment. So, P. indica and Zn were selected as efficient eco-contributors. An experiment for the detailed study of the selected eco-contributor was performed. Three drought-responsive genotypes were used (WC-297 drought tolerant, Caawa moderately drought tolerant and IR-64 drought susceptible) experimentation has proved that both of these selected eco-contributors have strengthened rice plant and stabilized its biomass, antioxidants as well as osmolite profile, mineral uptake, expression of important drought-responsive genes, chlorophyll contents, chloroplast integrity and the activity of antenna complex of the photosystem II. In the third experiment, hybridization of drought responsive genotypes with each other and with the modern cultivars was performed by following 6 x 6 diallel scheme. The F1 plants were accessed for the change in root length, shoot length, fresh root weight, fresh shoot weight, dry root weight, dry shoot weight, proline contents, total antioxidant activity and the concentration of phosphorus, calcium and zinc in leaves. Significant heterosis for these drought-related traits was recorded in both non-inoculated and inoculated plants of the F1 populations. In the fourth experiment, the yield of the rice plant was tried to increase in such a way that if these high yielding genotypes exposed to drought stress then even after yield losses these can provide substantial grain. For this purpose, the panicle architecture of the rice plants was exploited and high yielding populations were developed by using line x tester mating design. These new phenotypes were evaluated in low watered filed following randomized complete block design. Some genotypes in F2 population had potential to grow more than 197 additional grains than their better parents. On the basis of these interlinked experiments, it was concluded that rice germplasm keeps huge genetic diversity for inducing drought tolerance in modern cultivars. The screening of rice germplasm at germination stage using proline and total antioxidant capacity as markers accelerates the process of germplasm phenotyping. The inoculation of rice genotypes with P. indica under optimum supply of Zn stabilizes rice seedlings under drought stress. Hybridization among drought responsive genotypes and modern cultivars proved that these drought tolerant genotypes have the capacity to transfer drought-responsive traits in their imminent progenies. A modified rice panicle supports the high number of grains that can compensate yield losses under drought stress. An integrated approach is the best possible solution to save rice cultivation under increasing shortage of agricultural water.