IR and sub-mm fluxes of SN1987A revisited: when moderate dust masses suffice

We model the fluxes in the infrared and submillimeter domain using the dust chemical composition and mass derived from the physico-chemical model of a Type II-P supernova ejecta with stellar progenitor of 19 M ⊙. Our results highlight that the dust mass predicted to rise over time in our chemical models from 10−2 to 10−1 M ⊙ satisfactorily reproduce the infrared and sub millimeter fluxes. They confirm that type II-P SNe are efficient but moderate dust makers in galaxie

Blocking SQL Injection in Database Stored Procedures

This thesis contains a summary of all the work that has been done by us for the B-Tech project in the academic session of 2009-2010. The area chosen for the project was SQL Injection attacks and methods to prevent them, and this thesis goes on to describe four proposed models to block SQL Injection, all of them obtained from published research papers. It then gives the details of the implementation of the model “SQL Injection prevention in database stored procedures” as proposed by K. Muthuprasanna et al, which describes a technique to prevent injections attacks occurring due to dynamic SQL statements in database stored procedures, which are often used in e-commerce applications. The thesis also contains the algorithms used, data flow diagrams for the system, user interface samples and the performance reports. The particulars of some of the modifications made to the proposed model during implementation have also been documented, and there has also been included a section which discusses the possible updations that could be made to the tool, and future work

Molecules and dust in the ejecta of Type II-P supernovae

We study the formation of molecules and dust clusters in the ejecta of solar metallicity, Type II-P supernovae using a chemical kinetic approach and follow the evolution of molecules and small dust cluster masses from day 100 to day 1500 after explosion. We predict that large masses of molecules including CO, SiO, SiS, O2, and SO form in the ejecta. We show that the non-equilibrium chemistry results in a gradual build up of the dust mass from small (~10−5 M ⊙) to large values (~5×10−2 M ⊙) over a five-year period after explosion. This result provides a natural explanation to the discrepancy between the small dust masses detected at infrared wavelengths some 500 days post-explosion and the larger amounts of dust recently detected with the Herschel telescope in supernova remnant

Effect of coordination on topological phases on self-similar structures

Topologically nontrivial phases have recently been reported on self-similar structures. Here we investigate the effect of local structure, specifically the role of the coordination number, on the topological phases on self-similar structures embedded in two dimensions. We study a geometry dependent model on two self-similar structures having different coordination numbers, constructed from the Sierpinski gasket. For different nonspatial symmetries present in the system, we numerically study and compare the phases on both structures. We characterize these phases by the localization properties of the single-particle states, their robustness to disorder, and by using a real-space topological index. We find that both structures host topologically nontrivial phases and the phase diagrams are different on the two structures. This suggests that, in order to extend the present classification scheme of topological phases to nonperiodic structures, one should use a framework which explicitly takes the coordination of sites into account

Kinetics of Reduction of Vanadiferous Titanomagnetite ore of Orissa

200 mesh powder of vanadium bearing titaniferous magne-tite ore was pelletised to 0 5 cm dia spheres, heat hardened at 1100'C for z hour in nitrcgen. The pellets were reduced in a calibrated mixture of 60% N2, 40% CO. The temperature vs weight loss was recorded in a Shimad -zu Thermogravimeter model TGA-31 at 900, 955, 999 and 1050°C. The results conformed to Mc Kewan's phase bound-ary reaction model, yielding an activation energy of 25.5 kcal / mole. No kinetic studies of reduction of titan-omagnetite has been reported. The activation energy for magnetite reduction ranges from 13 to 45 kcal/mole as reported in literature. Presence of TiO 2 is known to hinder reduction kinetics of iron oxides. The observed higher activation energy and slower rate of reduction of titanomagnetite has been explained in terms of its spine/ structure and preferential positions of metal ions

Evaluation of FAOAqua Crop model for wheat under different irrigation regimes

The experiment was conducted at the research farm of the Water Technology Centre, IARI, New Delhi during rabi seasons of 2010-11and 2011-12. Irrigation treatments include irrigation applied at 50% deficit (W1) and 25 % deficit (W2) and full irrigation (W3) under recommended fertilization levels with split doses of N-fertilizer. Fullirrigation treatment was based on irrigations to meet the soil moisture deficit up to the field capacity (FC) level and deficit irrigation treatments of 25% and 50% were imposed with respect to the full irrigation.The model was calibrated with experiment generated data sets of rabi 2010-11 and validated using the data set of rabi 2011-12. It was observed that the validated model performed well for grain yield prediction with absolute prediction error of 2.9%, 0.91% and 7.85% for full, 25% deficit and 50% deficit irrigation levels, respectively. Also, for prediction of biomass yield the prediction error ranged from 11.81% to 28.96% for all three irrigation treatments. Moreover, the validated model was observed to predict the water productivity with absolute prediction errors of 43.57%, 13.87% and 12.8% for full, 25% deficit and 50% deficit irrigation treatment levels, respectively. Nonetheless, it was observed from this study that the AquaCrop model can be used to simulate the grain and biomass yield for wheat crop with acceptable accuracy under different irrigation regimes in a semi-arid enviroment

Strategies for climate change impacts on irrigated crops in National Capital Region of India

Irrigation has helped in increasing food production and achieving food security in India. However, climate change is expected to affect the crop production in irrigated area particularly in groundwater irrigated areas. This study was undertaken for suggesting strategies to climate change impact on irrigated crops based on projected change in crop water requirement and groundwater availability for irrigation in the National Capital Territory of Delhi. Prevailing groundwater recharge in the study area during monsoon was 4.01 MCM (Million cubic meter). The same for various scenarios varied from -15.47 MCM to 5.08 MCM. It was revealed that groundwater recharge would increase if it is estimated based on the climate prediction done using local weather data. The impact of climate change on groundwater availability is evident in scenarios based on INCCA and IPCC predictions where it varied from -2.66 MCM to 1.02 MCM. Contrary to common perceptions, crop water requirement of prevailing cropping system would not increase in future if all the important climatic parameters are considered for its prediction. This may be due to the fact that effect of increase in temperature on crop water requirement may be compensated by decrease in other climatic parameters such wind speed and duration of daily sunshine hours. Results indicated that climate change may not have much impact on sustainability of prevailing cropping system as per the crop water requirement is concerned. Based on water requirement and groundwater availability under various climate change scenarios, appropriate strategies to cope up the climate change impact on irrigated crops have been suggested

Effect of Particle Size on Surface-Coating Enhancement of Pool Boiling Heat Transfer

The enhancement of pool boiling heat transfer by copper-particle surface coatings is experimentally investigated, using the wetting dielectric fluid FC-72. In one technique, loose copper particles are placed on a heated copper surface to provide additional vapor nucleation sites in the cavities formed at particlesurface and particle-particle contact points, thereby enhancing boiling performance over a polished surface. This ‘free-particle’ technique is benchmarked against the more traditional technique of sintering a fixed layer of copper particles to the surface to enhance boiling heat transfer performance. The effect of particle size on the heat transfer performance is studied for particle diameters ranging from 45 μm to 1000 μm at a constant coating layer thickness-to-particle diameter ratio of approximately 4. The parametric trends in the boiling curve and the critical heat flux are compared between the two techniques, and the dominant boiling mechanisms influencing these trends are compared and contrasted. High-speed visualizations are performed to qualitatively assess the boiling patterns and bubble departure size/distribution, and thus corroborate the trends observed in the boiling curves. The measured wall superheat is significantly lower with a sintered coating compared to the free-particle layer for any given particle size and heat flux. Performance trends with respect to particle size, however, are remarkably similar for both enhancement techniques, and an optimum particle size of ~100 μm is identified for both free particles and sintered coatings. The free-particle technique is shown to offer a straightforward method to screen the boiling enhancement trends expected from different particulate layer compositions that are intended to be subsequently fabricated by sintering

Quantitative Evaluation of the Dependence of Pool Boiling Heat Transfer Enhancement on Sintered Particle Coating Characteristics

Immersion cooling strategies often employ surface enhancements to improve the pool boiling heat transfer performance. Sintered particle/powder coatings have been commonly used on smooth surfaces to reduce the wall superheat and increase the critical heat flux (CHF). However, there is no unified understanding of the role of coating characteristics on pool boiling heat transfer enhancement. The morphology and size of the particles affect the pore geometry, permeability, thermal conductivity, and other characteristics of the sintered coating. In turn, these characteristics impact the heat transfer coefficient and CHF during boiling. In this study, pool boiling of FC-72 is experimentally investigated using copper surfaces coated with a layer of sintered copper particles of irregular and spherical morphologies for a range of porosities (40-80%). Particles of the same effective diameter (90–106 lm) are sintered to yield identical coating thicknesses (4particle diameters). The porous structure formed by sintering is characterized using microcomputed tomography (l-CT) scanning to study the geometric and effective thermophysical properties of the coatings. The boiling performance of the porous coatings is analyzed. Coating characteristics that influence the boiling heat transfer coefficient and CHF are identified and their relative strength of dependence analyzed using regression analysis. Irregular particles yield higher heat transfer coefficients compared to spherical particles at similar porosity. The coating porosity, pore diameter, unit necking area, unit interfacial area, effective thermal conductivity, and effective permeability are observed to be the most critical coating properties affecting the boiling heat transfer coefficient and CHF