Effect of spheroidized microstructure on the impact toughness and electrochemical performance of a high-carbon steel

The influence of cementite spheroidization on the impact toughness and electrochemical properties of a high-carbon steel has been thoroughly investigated in this study. Heavy warm rolling, followed by 2 h of annealing, has resulted in near-complete spheroidization, leading to a microstructure consisting of nano-cementite globules dispersed in the ultrafine-grained ferritic matrix. The Charpy impact test exhibited superior impact toughness with increased spheroidization. It is validated by the presence of abundant dimples in the fractographs of spheroidized specimens, in contrast to the as-received one that experienced a brittle failure due to its lamellar pearlitic structure. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) carried out in a 3.5% NaCl solution revealed that the corrosion resistance of the alloy gets improved with the increase in the degree of spheroidization. This is attributed to the lower susceptibility of the spheroidized specimen to microgalvanic corrosion owing to the minimum area of contact between nano-spheroidized cementite and ferrite, as elucidated with the help of EIS results aided by equivalent electrical circuit model.     

Menadione-induced oxidative stress accelerates onset of Emory mouse cataract in vivo

This article takes issue with procedural reductionism, which is the inclination to reduce all matters of judgement and responsibility to the following of some procedure or rule. Two scenarios provide content for a discussion of professional discretion in the context of accountability. The author shows that in professional life there will always be situations that stand beyond the rules of procedures and require the unique judgement of the professional at the time. While this judgement may be determined by the facts available in a situation of uncertainty, it cannot be reduced to the facts (including facts about rules and procedures). The moral judgement will still have an essential indeterminancy about it.     

Skin detection in video under uncontrolled illumination

Multimedia Tools and Applications - Many vision-based human-computer interaction (HCI) applications require skin detection. However, their performance relies on accuracy in detecting skin regions...     

Secure image encryption scheme using high efficiency word-oriented feedback shift register over finite field

Multimedia Tools and Applications - Image encryption is an evolving technique in the arena of data communication. In the last decade, many encryption schemes have been suggested. Unfortunately,...     

Impact of zonal wind on latitudinal variation of total columnar ozone over the Indian Peninsula

Latitudinal and seasonal variability of total columnar ozone from September 2007 to August 2008 across the Indian longitude sector within 10.5° N to 34.5° N and 70.5° E to 94.5° E using satellite data obtained from Aura Ozone Monitoring Instrument (OMI) of National Aeronautics and Space Administration (NASA) Earth Observing System (EOS) is presented. The total column ozone (TCO) over the area of study shows a gradually varying pattern throughout the year. In the post-monsoon (autumn) and winter months, maximum TCO is observed in the north-western part of the subcontinent while the minimum is often observed towards the east at about the same latitudes. A west–east spatial gradient is clearly observed in autumn months. As winter approaches, a north–south spatial gradient becomes more prominent than the east–west gradient. It has been further observed that TCO does not vary significantly over the entire subcontinent in monsoon.     

Load Balancing in a Cluster-Based Web Server for Multimedia Applications

We consider a cluster-based multimedia Web server that dynamically generates video units to satisfy the bit rate and bandwidth requirements of a variety of clients. The media server partitions the job into several tasks and schedules them on the backend computing nodes for processing. For stream-based applications, the main design criteria of the scheduling are to minimize the total processing time and maintain the order of media units for each outgoing stream. In this paper, we first design, implement, and evaluate three scheduling algorithms, first fit (FF), stream-based mapping (SM), and adaptive load sharing (ALS), for multimedia transcoding in a cluster environment. We determined that it is necessary to predict the CPU load for each multimedia task and schedule them accordingly due to the variability of the individual jobs/tasks. We, therefore, propose an online prediction algorithm that can dynamically predict the processing time per individual task (media unit). We then propose two new load scheduling algorithms, namely, prediction-based least load first (P-LLF) and prediction-based adaptive partitioning (P-AP), which can use prediction to improve the performance. The performance of the system is evaluated in terms of system throughput, out-of-order rate of outgoing media streams, and load balancing overhead through real measurements using a cluster of computers. The performance of the new load balancing algorithms is compared with all other load balancing schemes to show that P-AP greatly reduces the delay jitter and achieves high throughput for a variety of workloads in a heterogeneous cluster. It strikes a good balance between the throughput and output order of the processed media units     

Performance of multiprocessor interconnection networks

A tutorial is provided on the performance evaluation of multiprocessor interconnection networks, to guide system designers in their design process. A classification of parallel/distributed systems is followed by a classification of multiprocessor interconnection networks. Basic terminology for performance evaluation is presented. The performance of crossbar interconnection networks, multistage interconnection networks, and multiple-bus systems is then addressed, and a comparison is made along them     

Chemical modification of lignocellulosic fibers I. Functionality changes and graftcopolymerization of acrylonitrile onto pineapple leaf fibers; their characterization and behavior

This paper is an attempt to examine the commercial significance of an agro-waste “pineapple leaf fiber” (PALF). The quality enhancement of PALF has been tried through chemical modifications. Functionality changes in the above fiber have been done through mercerization, cyanoethylation, oxidation, and graftcopolymerization with acrylonitrile, using cericion as an initiator at varying concentrations of monomer, initiator, and mineral acid at a number of temperatures for various time intervals. The modified fibers have been characterized by FTIR spectroscopy and viscosity measurements. The extent of moisture regain, acid-alkali solubility, tensile modulus, dye-uptake ability, and thermal stability of the resulting materials have been tested and compared with the parent fiber. The significance of such chemical modification in the context of better textile performance and reinforcing behavior of the product in FRP has been discussed. © 1994 John Wiley & Sons, Inc.     

Design of an adaptive cache coherence protocol for large scalemultiprocessors

A large scale, cache-based multiprocessor that is interconnected by a hierarchical network such as hierarchical buses or a multistage interconnection network (MIN) is considered. An adaptive cache coherence scheme for the system is proposed based on a hardware approach that handles multiple shared reads efficiently. The new protocol allows multiple copies of a shared data block in the hierarchical network, but minimizes the cache coherence overhead by dynamically partitioning the network into sharing and nonsharing regions based on program behavior. The new cache coherence scheme effectively utilizes the bandwidth of the hierarchical networks and exploits the locality properties of parallel algorithms. Simulation experiments have been carried out to analyze the performance of the new protocol. The simulation results show that the new protocol gives 15% to 30% performance improvement over some existing cache coherence schemes on similar systems for a wide range of workload parameters     

An availability model for MIN-based multiprocessors

System decomposition is a novel technique for modeling the dependability of complex systems without constructing a single-level Markov Chain (MC). This is demonstrated in this paper for the availability computation of a class of multiprocessors that uses 4×4 switching elements for the multistage interconnection network (MIN). The availability model is known as task-based availability, where a system is considered operational as long as the task requirements are satisfied. The authors develop two simple MC's for the processors and memories and solve them using a software package, called HARP. The probabilities of i processing elements (PE's) and j memory modules (MM's) working at any time t, denoted as Pi(t) and Pj(t), are obtained from their corresponding MC's. The effect of the MIN is captured in the model by finding the number of switches required for the connection of i PE's and j MM's. A third MC is then developed for the switches to find the probability that the MIN provides the required (i×j) connection. Multiplying this term with Pi(t) and Pj(t), the probability of an (i×j) working group is obtained. The methodology is generalized to model arbitrary as well as larger size systems. Transient and steady state availabilities are computed for a variety of MIN configurations and the results are validated through simulation