Dry sliding wear response of zinc-based alloy over a range of test speeds and loads: a comparative study with cast iron

This study pertains to the observations made during the sliding wear response of a zinc-based alloy in different test conditions. The effects of sliding speed and load on the wear behaviour of the alloy have been studied. The properties evaluated were wear rate, frictional heating and coefficient of friction. The wear performance of the zinc-based alloy has been compared with that of a conventional cast iron in identical test conditions. The wear rate of the samples increased with applied load and sliding speed while the seizure resistance (load) deteriorated with speed. The zinc-based alloy exhibited less wear rate and reduced frictional heating than that of the cast iron while friction coefficient followed a reverse trend. Observed wear response of the samples has been discussed in terms of specific features like lubricating, load carrying, microcracking and thermal stability of various microconstituents of the samples, and substantiated further through the features of wear surfaces, subsurface regions and debris.     

Growth and consumption rates of the phase layers during interdiffusion in a diffusion couple with finite end member

The relations for the growth and consumption rates of a layer with finite thickness as an end member and the product phases in the interdiffusion zone are developed. We have used two different methodologies, the diffusion based and the physico-chemical approach to develop the same relations. We have shown that the diffusion based approach is rather straightforward; however, the physico-chemical approach is much more versatile than the other method. It was found that the position of the marker plane becomes vague in the second stage of the interdiffusion process in pure A thin layer/B couple, where two phases grow simultaneously.     

Detecting localized homogeneous anomalies over spatio-temporal data

The last decade has witnessed an unprecedented growth in availability of data having spatio-temporal characteristics. Given the scale and richness of such data, finding spatio-temporal patterns that demonstrate significantly different behavior from their neighbors could be of interest for various application scenarios such as—weather modeling, analyzing spread of disease outbreaks, monitoring traffic congestions, and so on. In this paper, we propose an automated approach of exploring and discovering such anomalous patterns irrespective of the underlying domain from which the data is recovered. Our approach differs significantly from traditional methods of spatial outlier detection, and employs two phases—(i) discovering homogeneous regions, and (ii) evaluating these regions as anomalies based on their statistical difference from a generalized neighborhood. We evaluate the quality of our approach and distinguish it from existing techniques via an extensive experimental evaluation.     

Morphology,Mineralogy and Mixing of Individual Atmospheric Particles Over Kanpur (IGP): Relevance of Homogeneous Equivalent Sphere Approximation in Radiative Models

Estimation of the direct radiative forcing (DRF) by atmospheric particles is uncertain to a large extent owing to uncertainties in their morphology (shape and size), mixing states, and chemical composition. A region-specific database of the aforementioned physico-chemical properties (at individual particle level) is necessary to improve numerically-estimated optical and radiative properties. Till date, there is no detailed observation of the above mentioned properties over Kanpur in the Indo-Gangetic Plain (IGP). To fill this gap, an experiment was carried out at Kanpur (IITK; 26.52°N, 80.23°E, 142 m msl), India from April to July, 2011. Particle types broadly classified as (a) Cu-rich particles mixed with carbon and sulphur (b) dust and clays mixed with carbonaceous species (c) Fe-rich particles mixed with carbon and sulfur and (d) calcite (CaCO₃) particles aged with nitrate, were observed. The frequency distributions of aspect ratio (AR; indicator of extent of particle non-sphericity) of total 708 particles from April to June reveal that particles with aspect ratio range >1.2 to ≤1.4 were abundant throughout the experiment except during June when it was found to shift to high AR range, >1.4 to ≤1.6 (followed with another peak of AR i.e. >2 to ≤2.4) due to dust storm conditions enhancing the occurrence of more non-spherical particles over the sampling site. The spherical particles (and close to spherical shape; AR range, 1.0 to ≤1.2) were found to be <20% throughout the experiment with a minimum (11.5%) during June. Consideration of Homogeneous Equivalent Sphere Approximation (HESA) in the optical/radiative model over the study region is found to be irrelevant during the campaign.     

印度兰吉特大坝的泥沙管理

印度兰吉特河(Rangit)是提斯塔河(Teesta)的主要支流,位于东喜马拉雅地区。兰吉特水电站装机60 MW,于2000年2月投入运行。每年5~9月汛期之间,兰吉特河输沙量巨大,2006年,该电站发生水淹厂房事故。     

Effect of Temperature on Hydraulic Parameters of Cable-In-Conduit-Conductor of SST-1

Stable operation of superconducting magnets depend critically on the balance of heat deposition rate versus heat extraction rate by the cryo-coolant. Thus, the mass flow rate of the coolant in case of force-flow cooled superconducting magnet with Cable-In-Co-nduit-Conductor (CICC) construction becomes an important factor for optimum stability of magnets. The Toroidal and Poloidal Field magnets of Steady-state Superconducting Tokamak-1 (SST-1) is made of superconducting CICC with a void fraction of 40 %±2 %. For adequate cooling of magnets, supercritical helium at 4 bar and 4.5 K is forced-flown through the voids. Effect of temperature on mass flow rate and pressure drop in SST-1 CICC is studied in a 7 m long piece wound helically. The experimental friction factor of the CICC is also measured at different temperatures and flow rates and is compared with the standard Katheder equation and Tada equation. Also, based on the new findings obtained from the experimental results, the dimensionless Reynolds number has been slightly modified. This new number is used to propose a modified Katheder correlation for the friction factor in CICCs similar to that of SST-1.     

Dielectric relaxation in complex perovskite Ba(Bi1/2Ta1/2)O3

A new lead-free perovskite Ba(Bi_1/2Ta_1/2)O₃ was prepared by conventional ceramic fabrication technique at 1,200 °C/4 h in air atmosphere. The crystal symmetry, space group and unit cell dimensions were determined from the experimental results using FullProf software. The crystallite size and lattice strain were estimated from Williamson-Hall approach. XRD analysis of the compound indicated the formation of a single-phase cubic structure with the space group Pm3m. EDAX and SEM studies were carried out in order to evaluate the quality and purity of the compound. Permittivity data showed a low temperature coefficient of capacitance (T _CC  < 4%) up to +125 °C. Complex impedance analyses suggested the dielectric relaxation to be of non-Debye type. Electric modulus studies supported the hopping type of conduction in Ba(Bi_1/2Ta_1/2)O₃.     

Samarium Ion-Doped Maghemite Nanoparticles: Synthesis,Microstructural, Optical,and Magnetic Characterizations

Journal of Superconductivity and Novel Magnetism - This paper reports the effects of rare-earth Sm3+ ion substitution on structural, optical, electronic, and magnetic responses of maghemite...     

SLDG: a metamodel for Simulink/Stateflow models and its applications

Simulink and Stateflow (SL/SF) models are being widely used to design and develop embedded systems. Often the SL/SF models of embedded controllers turn out to be large and consist of many subsystems and hierarchies. When such a system is maintained, it becomes difficult to manually analyse the model to identify the impacted elements due to the existence of several explicit and implicit dependencies among the model elements. To automate the analysis of an SL/SF model, we propose a metamodel to capture various types of dependencies existing across the basic blocks. We have named this metamodel Simulink dependency graph (SLDG). We investigate the use of SLDG in change impact visualization and regression test selection. We have developed a prototype tool by implementing our approach for the aforementioned applications.