Identification of Shocks in the Spectra from Black Holes

We study the spectral properties of a low angular momentum flow as a function of the shock strength, compression ratio, accretion rate and flow geometry. In the absence of a satisfactory description of magnetic fields inside the advective disk, we consider the presence of only stochastic fields and use the ratio of the field energy to the gravitational energy density as a parameter. We not only include `conventional' synchrotron emission and Comptonization by Maxwell-Bolzmann electrons in the gas, but we also compute these effects due to power-law electrons. For strong shocks, a bump is produced due to the post-shock flow. A power-law spectral components due to the thermal and non-thermal electrons appear after this bump.Comment: 8 pages, 5 figures, Astronomy and Space Science (in press), Proceedings of the Hong Kong Conference (2004) Edited by Cheng and Romer

Impact of Hole Depth on Vibration Magnitude vis-a-vis Minimization of Vibration Level for Safe Opencast Operation

Excavation of locked up coal pillars by opencast method and presence of dwellings in close proximity to such operation needs a specialized drilling and blasting plan for its safe excavation. Introduction of private entrepreneurs sometimes urges the operating personnel and practicing engineers to introduce unsafe blast design parameters with respect to bench height for extraction of coal by opencast method. Implementation of sub-optimal blast design parameters due to mismatched drilling equipment leads to complaints from local inhabitants, damage to structures and even casualties as a result of undesired throw of basted fragments. Comparing magnitude of vibration generated from different drill hole diameters, depth of hole and type of explosive (bulk or cartridge) this paper communicates that a maximum of 110 mm drill diameter and 83 mm cartridge diameter should be implemented for safe excavation, especially when the structures are with in 100m from the place of blasting. Whe3n the structures are between 50m and 100m, depth of blast hole should not be more than 5 m to contain the magnitude of vibration with in safe limit. Due to high coupling factor for bulk loaded explosives, the attenuation rate of vibration for a given range of distance is low and should not be implemented when structures are with in 100m from the place of blasting. For structures beyond 120m from the place of blasting, bulk explosive may be implemented by limiting the bench height. Depth of holes and drill diameter for such cases may be between 8m and 10m and 110 mm and 160 mm, respectively. The paper also communicates that for the excavation work in close proximity to structures, burden should be less than optimum with respect to concerned bench height to contain the magnitude of vibration with the permissible limi

Achieving energy efficiency in buildings design through innovative planning and design solutions

The idea that the, earth is a finite planet in the mathematical sense is commonly accepted today. In 1972, both the Club of Rome, in its report, (Meadows et al, 1972), and the first Earth summit in Stockholm expressed this idea. This amounts to all its resources including fossil energy being limited. Renewable resources, already partially tapped, will only replace a portion of this energy. This substitution will be difficult to accomplish since the level of predation of human beings on the planet is causing serious malfunctioning of the biosphere. The building sector does not escape from today’s spotlight on the environmental impacts of human activities. Buildings are major energy consumer during both construction and ‘usage, and also generate large quantities of waste. Built up structures are consumers of 40% of the global primary energy and generator of 24% co2 emission. As such, criticality of buildings and their role in minimizing energy consumption and promoting sustainability of human habitat assumes importance. The options relating to building materials, building technologies, landscaping, heating and cooling system etc have already been explored. It is logical to apply the principles of energy costing to building prospects and look for ways to minimize energy consumption during their entire lifetime. Accordingly, the paper focuses on design strategies for making building highly energy efficient and sustainable in terms of site planning, macro and micro climatic conditions, landscaping, orientation, fenestration and shading and building materials. It discusses two case studies from India incorporating innovative design solutions to achieve energy efficiency

Influence of Demagnetization Effect on Giant Magneto Impedance of soft Ferromagnetic Metal

The large change in electromagnetic impedance in ferromagnetic state of soft magnetic metals in presence of biasing magnetic field is associated with change in screening of electromagnetic field. The screening depends on the permeability of the metal. Apart from dependence on intrinsic properties of metal the permeability depends on size of the sample. It is observed that the decrease in MI in amorphous ferromagnetic ribbon of Fe40Ni40B20 alloy is large for long sample whereas corresponding change is small for short one with same biasing field. As intrinsic magnetic properties and bias field are same and the demagnetization factor increases with reduction of length of the sample the reduction of MI effect is associated with demagnetization field.Comment: 14 pages,4 figure

Study of α-transfer reaction 28Si( 7Li, t) 32S

The 28Si( 7Li, t) 32S reaction has been studied at 48 MeV. Using a αt potential overlap based on a microscopic cluster model, the full finite-range distorted wave Born approximation analysis was carried out for nine low-lying states; 0.0 MeV (0+), 2.23 MeV (2+), 3.78 MeV (0+), 4.46 MeV (4+), 5.01 MeV (3-), 5.80 MeV (1-), 6.76 MeV (3-), 7.43 MeV (1-) and 8.49 MeV (1-) of the residual nucleus. A re-analysis was also done for the same states of 32S having an αd overlap for the reaction 28Si (6Li, d) 32S at 75.6 MeV. Theoretical spectroscopic factors have been calculated for the measured even-parity states of 32S using the shell model code OXBASH. The spectroscopic factors were compared for both the reactions

Wide-angle α-t coincidence measurement in the breakup of 7Li on 27Al

We have performed wide-angle in-plane coincidence measurements of the alpha particles and tritons emitted in the 48-MeV 7Li projectile breakup reaction on 27Al. The data have been analyzed using the post-form distorted-wave Born-approximation (DWBA) theory of breakup reactions where Coulomb and nuclear breakup as well as their interference terms are included. The theory is able to provide a good description of the experimental data particularly at large relative angles between the fragments. The interference between the Coulomb and nuclear breakup modes is found to be significant

ANATOMICAL DISPOSITION OF CARPAL BONES OF GOLDEN RETRIEVER DOG BY X-RAY EXPOSURE

The present study was conducted to know the general disposition of bones in carpal region of experimental dogs by X-ray study with an objective that the findings will facilitate to have an in-depth knowledge about the proper positioning of the carpal bones for surgical management of fractures and different types of bone deformities in dogs. In the present study, the anatomical disposition and arrangement pattern of carpal bones playing a pivotal role in providing the structural conformity in the limbs of Golden Retriever dog has been thoroughly confirmed by Xray exposure

Theoretical evaluation of energy from blast-induced vibration waves measured on ground and structure

Legislation of limiting blast-inducted vibration level measure near foundation of structure have imposed difficulty in quarrying operation. Confrontation towards excavation work rises to its peak when drilling and blasting activity is carried out in close proximity to structures. Considering the sustaining capacity of structures towards high magnitude blast-induced ground vibration, the paper analyzes characteristics and quantum of energy transmitted to structure at the place of measurement. Theoretical model developed to evaluate wave characteristic and quantum of energy contained in blast wave signatures has been used for analysis. Comparative analysis of wave characteristics and quantum of energy transmitted at different distances/heights of concern is detailed in the paper. The paper firstly makes a comparative analysis of characteristics and energy contained in peak magnitude and wave signatures measured on ground at different distances of measurement and thereafter, compares wave signatures monitored near foundation of structure and first floor of a two storied structure, located within 50 m from blasting site

Coupled channel description of 16O+142,144,146Nd scattering around the Coulomb barrier using a complex microscopic potential

Angular distributions of elastic scattering and inelastic scattering from 2+ 1 state are measured for 16O+142,144,146Nd systems at several energies in the vicinity of the Coulomb barrier. The angular distributions are systematically analyzed in coupled channel framework. Renormalized double folded real optical and coupling potentials with DDM3Y interaction have been used in the calculation. Relevant nuclear densities needed to generate the potentials are derived from shell model wavefunctions. A truncated shell model calculation has been performed and the calculated energy levels are compared with the experimental ones. To simulate the absorption, a 'hybrid' approach is adopted. The contribution to the imaginary potential of couplings to the inelastic channels, other than the 2+ 1 target excitation channel, is calculated in the Feshbach formalism. This calculated imaginary potential along with a short ranged volume Woods-Saxon potential to simulate the absorption in fusion channel reproduces the angular distributions for 16O+146Nd quite well. But for 16O+142,144Nd systems additional surface absorption is found to be necessary to fit the angular distribution data. The variations of this additional absorption term with incident energy and the mass of the target are explored. © 2003 Elsevier Science B.V. All rights reserved

Web Usage Mining: A Survey on Pattern Extraction from Web Logs

As the size of web increases along with number of users, it is very much essential for the website owners to better understand their customers so that they can provide better service, and also enhance the quality of the website. To achieve this they depend on the web access log files. The web access log files can be mined to extract interesting pattern so that the user behaviour can be understood. This paper presents an overview of web usage mining and also provides a survey of the pattern extraction algorithms used for web usage mining