Erosion wear response of ramie-epoxy composites using artificial neural network integrated with Taguchi technique

This paper aims on evaluating the erosion wear behavior of epoxy composites reinforced with ramie fibers. The possibility of reinforcing ramie fiber to improvise the wear resistance of epoxy is investigated in this study. Composites are fabricated by reinforcing multiple layers of woven ramie fiber mats into epoxy resin using conventional wet lay-up technique and erosion wear trials are conducted using solid particle erosion test setup. Taguchi analysis is done to assess the relative significance of each of the factors influencing the erosion rate using L₁₆ orthogonal array. The analysis reveals that the impact velocity followed by impingement angle are the most significant control factors affecting the erosion wear rate of ramie-epoxy composites. Steady state erosion analysis is done to ascertain the effect of each of the significant factors while keeping other factors fixed. Further, an analytical and predictive model based on the principle of neural computation is used to predict the rate of erosion wear of the composites and the obtained results are compared with the experimental outcomes. The worn morphologies of the eroded surfaces of the composites are studied and analyzed to identify possible mechanisms causing wear.     

A particle swarm approach for multi-objective optimization of electrical discharge machining process

This paper proposes an experimental investigation and optimization of various machining parameters for the die-sinking electrical discharge machining (EDM) process using a multi-objective particle swarm (MOPSO) algorithm. A Box–Behnken design of response surface methodology has been adopted to estimate the effect of machining parameters on the responses. The responses used in the analysis are material removal rate, electrode wear ratio, surface roughness and radial overcut. The machining parameters considered in the study are open circuit voltage, discharge current, pulse-on-time, duty factor, flushing pressure and tool material. Fifty four experimental runs are conducted using Inconel 718 super alloy as work piece material and the influence of parameters on each response is analysed. It is observed that tool material, discharge current and pulse-on-time have significant effect on machinability characteristics of Inconel 718. Finally, a novel MOPSO algorithm has been proposed for simultaneous optimization of multiple responses. Mutation operator, predominantly used in genetic algorithm, has been introduced in the MOPSO algorithm to avoid premature convergence. The Pareto-optimal solutions obtained through MOPSO have been ranked by the composite scores obtained through maximum deviation theory to avoid subjectiveness and impreciseness in the decision making. The analysis offers useful information for controlling the machining parameters to improve the accuracy of the EDMed components.     

TCAM architecture for IP lookup using prefix properties

In modern IP routers, Internet protocol (IP) lookup forms a bottleneck in packet forwarding because the lookup speed cannot catch up with the increase in link bandwidth. Ternary content-addressable memories (TCAMs) have emerged as viable devices for designing high-throughput forwarding engines on routers. Called ternary because they store don't-care states in addition to 0s and 1s, TCAMs search the data (IP address) in a single clock cycle. Because of this property, TCAMs are particularly attractive for packet forwarding and classifications. Despite these advantages, large TCAM arrays have high power consumption and lack scalable design schemes, which limit their use. We propose a two-level pipelined architecture that reduces power consumption through memory compaction and the selective enablement of only a portion of the TCAM array. We also introduce the idea of prefix aggregation and prefix expansion to reduce the number of routing-table entries in TCAMs for IP lookup. We also discuss an efficient incremental update scheme for the routing of prefixes and provide empirical equations for estimating memory requirements and proportional power consumption for the proposed architecture.     

Estimation of composite damage model parameters using spectral finite element and neural network

A multi-layer perceptron (MLP) network using error back propagation algorithm is employed in this paper to estimate the damage parameters from broad-band spectral data as diagnostic signal. Various existing models of damage in laminated composite and the resulting stiffness degradation are discussed from comparative view-point. Degradation of ply properties can be considered to be one of the damage model parameters while monitoring transverse matrix cracks in cross-ply, splitting in longitudinal ply, and evolution of consecutive stages of damage, such as delaminations and fiber fracture. The stiffness degradation factor, the location and size of the damaged zone in laminated composite beam are considered as damage model parameters in the present paper. Fourier spectral data, which is typical to most of the diagnostic wave measurements, are used as input to the neural network. Since, training the neural network in such case involves many data sets and all of these data are difficult to generate using experiments, a spectral finite element model (SFEM) with embedded degraded zone in laminated composite beam is developed. Numerical simulation using this element is carried out, which shows the nature of temporal signal that are likely to be measured. Analytical studies on the performance of the neural network are presented based on numerically simulated data. Effect of measurement noise on the network performance is also reported.     

Recent progress on commercialization of castrip® direct strip casting technology at Nucor Crawfordsville

The world’s first commercial installation for direct casting of low-carbon steel sheet utilizing CASTRIP® technology is undergoing production ramp-up at Nucor Steel’s plant in Crawfordsville, Indiana. Construction of the plant was initiated in February 2001 and the first ladle was delivered to the caster in May 2002. Since that time, Nucor Steel has been working with technology partners BlueScope Steel (formerly BHP Steel) and IHI (Ishikawajima-Harima Heavy Industries) to fully commercialize this exciting new technology for the direct production of steel sheet less than 2 mm in thickness.     

Wild edible fruit diversity and its significance in the livelihood of indigenous tribals: Evidence from eastern India

A number of wild plants, used by rural and tribal populations and contributing significantly to their livelihood and food security have escaped recognition and scientific inquiry. Their distribution, conservation, mode of harvest by locals and optimal use require region-specific assessment in order to integrate them into developmental interventions. This study analyzed the collection, consumption, sale and income from edible forest fruits in 49 tribal villages spread over five districts of Orissa State in eastern India. Density, dominance and diversity of species yielding wild fruit were measured by studying ecological parameters in the sample plots. We estimated an average of 48 fruit plants per hectare of deciduous forests. Fifty-six wild edible fruit species belonging to 40 genera in 26 families were recorded in the study region, many of which have multiple uses. Indigenous fruits formed part of the family diet with average annual consumption of 73 kg per household. Sale of wild fruits contributed 15 % of income for tribal households. Despite their good knowledge of indigenous fruits, the tribal populations have not adopted fruit tree farming which would enhance their nutrition and income.     

Grain boundaries between bismuth nanocrystals

Grain boundaries in thin Bi(1 1 0) films deposited on highly oriented pyrolytic graphite are investigated at atomic resolution using scanning tunnelling microscopy and high-resolution transmission electron microscopy. We find preferred misorientation angles Θ equal to 216°, 87°, 49°, 31°, 20°, 12° and 5°, the majority of which can be classified as large-angle boundaries. We find good agreement between the experimental results and a model of the tilt [1 1 0] grain boundary developed here. A method for estimating the surface unit cell based on measurement of dihedral angle in low-resolution images is also developed.     

A comprehensive modeling framework for gate stack process dependence of DC and AC NBTI in SiON and HKMG p-MOSFETs

A comprehensive modeling framework involving mutually uncorrelated contribution from interface trap generation and hole trapping in pre-existing, process related gate insulator traps is used to study NBTI degradation in SiON and HKMG p-MOSFETs. The model can predict time evolution of degradation during DC and AC stress, time evolution of recovery after stress, impact of stress and recovery bias and temperature, and impact of several AC stress parameters such as pulse frequency, duty cycle, duration of last pulse cycle (half or full) and pulse low bias. The model can successfully explain experimental data measured using fast and ultra-fast methods in SiON and HKMG devices having different gate insulator processes. The trap generation and trapping sub components of the composite model have been verified by independent experiments. Data published by different groups are reconciled and explained. The model can successfully predict long time DC and AC stress data and has been used to determine device degradation at end of life as EOT is scaled for different HKMG devices.     

Cationic surface segregation in doped LaMnO<Subscript>3</Subscript>

The surface cation chemistry in (La, A)MnO₃ (A = Ca, Sr and Ba) is investigated using first-principles thermodynamics. We find that, all three dopants tend to segregate to the surface over a wide range of T– \( p_{{{\text{O}}_{2} }} \) conditions and the tendency for segregation increases with the increase in the dopant cationic size. Moving toward the low oxygen pressure, dopants prefer to remain in the surface regions accompanied by the appropriate number of charge compensating oxygen vacancies. The situation when dopants remain in the bulk regions tends to occur close to the thermodynamic conditions that also favor the decomposition of LaMnO₃. The present work serves as an important step toward understanding of factors governing the cationic surface segregation in doped LaMnO₃ and opens a pathway to study other important chemical environments (such as water- and CO₂-containing air) which are crucially given the fact that the ‘real-world’ air enhances cationic segregation.