Effective parameter study for the facile and controlled growth of silver molybdate nano/micro rods

Controlled growth of nano/micro structures by controlling the effective parameters is the basic requirement for the application point of view in various areas. Here we report the facile growth of silver molybdate nano/micro rods by mixing the solution of silver nitrate and ammonium molybdate at ambient condition followed by hydrothermal treatment at various temperatures for 12 h. To achieve the goal for the synthesis of long, high yield and homogeneous nanorods various effective parameters have been studied to set the most effective conditions for the growth. Among possible effective parameters first the temperature of the furnace was set by warring the temperature and then at the set temperature the concentration of reactants (NH₄)₆Mo₇O₂₄ and silver nitrate are varied respect to each other. The pH and temperature values were monitored during the mixing of the reactants. Structural/microstructural characterization revealed the optimum condition of 150°C of the furnace and the concentration of (NH₄)₆Mo₇O₂₄ and silver nitrate as described in various tables.     

Phase Diagram and Upper Critical Field of Homogeneously Disordered Epitaxial 3-Dimensional NbN Films

We report the evolution of superconducting properties with disorder, in 3-dimensional homogeneously disordered epitaxial NbN thin films. The effective disorder in NbN is controlled from moderately clean limit down to Anderson metal?Cinsulator transition by changing the deposition conditions. We propose a phase diagram for NbN in temperature-disorder plane. With increasing disorder, we observe that as k _F l??1 the superconducting transition temperature (T _c ) and normal state conductivity in the limit T??0 (?? ₀) go to zero. The phase diagram shows that in homogeneously disordered 3-D NbN films, the metal?Cinsulator transition and the superconductor?Cinsulator transition occur at a single quantum critical point, k _F l??1.     

Investigation of machining characteristics in rotary ultrasonic machining of alumina ceramic

Alumina ceramic is well documented as a much-demanded advanced ceramic in the present competitive structure of manufacturing and industrial applications owing to its excellent and superior properties. The current article aimed to experimentally investigate the influence of several process variables, namely: spindle speed, feed rate, coolant pressure, and ultrasonic power, on considered machining characteristics of interest, i.e., chipping size and material removal rate in the rotary ultrasonic machining of alumina ceramic. Response surface methodology has been employed in the form of a central composite rotatable design to design the experiments. Variance analysis testing has also been performed with a view to observing the consequence of the considered parameters. The microstructure of machined rod samples was evaluated and analyzed using a scanning electron microscope. This analysis has revealed and confirmed the presence of plastic deformation that caused removal of material along with brittle fractures in rotary ultrasonic machining of alumina ceramic. The validity and competence of the developed mathematical model have been verified with test results. The multi-response optimization of machining responses (material removal rate and chipping size) has also been attempted by employing a desirability approach, and at an optimized parametric setting the obtained experimental values for material removal rate and chipping size were 0.4166?mm³/s and 0.5134?mm, respectively, with a combined desirability index value of 0.849.     

A parametric study of strength reduction factors for elasto-plastic oscillators

Strength reduction factors (SRFs) continue to play a key role in obtaining design forces from elastic design spectra (via response modification factors) in ductility-based earthquake-resistant design. Despite several years of sustained research efforts, it has not been conclusively shown how SRF for a given singledegree-of-freedom structural system depends on various source and site parameters. A parametric study is carried out here for the explicit dependence of SRF spectrum (describing variation of SRF with system period for a given ductility demand) on strong motion duration, earthquake magnitude, geological site conditions, and epicentral distance in case of (non-degrading) elasto-plastic oscillators. For this, scaled response spectra are considered for different combinations of earthquake magnitude, site conditions and epicentral distance, and SRF spectra are generated from 1274 accelerograms recorded in western USA after making those compatible with each of these spectra. It is shown that there is no clear and significant dependence of SRF spectrum on strong motion duration. Further, the parametric dependence on earthquake magnitude, site conditions, and epicentral distance broadly conforms to the trends reported by earlier investigations. In particular, this study confirms that the dependence of SRF spectra on earthquake magnitude should not be ignored. This paper has been contributed in honour of Professor R N Iyengar, Indian Institute of Science, on the occasion of his formal retirement.     

Effect of Interlayer Interaction on the Specific Heat of High-Tc Superconductors

The effect of interlayer interactions on the electronic specific heat of high-T _c layered superconductors has been studied within the framework of the Hirsch model. In the present paper we extend our previous work in order to evaluate the expression for specific heat. It is shown that the inclusion of interlayer interactions suppresses the height of the jump in the specific heat at T _c.     

Studies on poly (hydroxy alkanoates)/(ethylcellulose) blends

Biodegradable polymers represent one of the most significant area of research today. Among these polymers, poly (β-hydroxy butyrate co β′-hydroxy valerate) i.e. PHBV have received special attention because of their unique combination of properties. They are perfectly biocompatible, biodegradable polymers and can be processed by any conventional technique. In the present study an attempt has been made to develop the biodegradable blends of PHBV by blending them with ethyl cellulose (EC). Ethyl cellulose has been selected to monitor the biodegradation rate of PHBV and also for making the blends cost effective. The blends are thoroughly characterized for their compatibility, by the measurement of viscosity of blends and through FT-IR. Various applications of PHBV/EC blend in agriculture and pharmaceutical industries are being explored. Paper presented at the 5th IUMRS ICA98, October 1998, Bangalore.     

Advanced Scout: Data Mining and Knowledge Discovery in NBA Data

Advanced Scout is a PC-based data mining application used by National Basketball Association (NBA)coaching staffs to discover interesting patterns in basketball game data. We describe Advanced Scout software from the perspective of data mining and knowledge discovery. This paper highlights the pre-processing of raw data that the program performs, describes the data mining aspects of the software and how the interpretation of patterns supports the processof knowledge discovery. The underlying technique of attribute focusing asthe basis of the algorithm is also described. The process of pattern interpretation is facilitated by allowing the user to relate patterns to video tape.     

Determination of the interfacial heat transfer coefficient in a metal-metal system solving the inverse heat conduction problem

Simulation of several industrial processes involving solidification of metals requires characterization of heat transfer coefficient at the solidifying metal/metal-substrate interface. In the present investigation an attempt has been made to estimate this heat transfer coefficient, h_c, using simulated experiments in which the heat transfer from a heated stainless steel block (simulating solidifying metal) to a water cooled copper block (simulating metal-substrate) is monitored by continuously recording temperatures at a few internal locations both within the metal block and the substrate block. The problem of determining the interfacial heat transfer coefficient is recognized to be an inverse heat conduction problem (IHCP). A numerical method is employed to solve IHCP and to determine the h_c from the transient history of temperatures at a few locations. The effect of the physical nature of the interface, as well as the cooling conditions prevailing at the outer surface of the substrate on h_c is examined and discussed. While the physical nature of the interface, i.e. roughness on the metal as well as the substrate surfaces, has a significant effect on h_c, the cooling conditions have only a marginal effect. The h_c in the present investigation remains more or less time invariant.