Synthesis and properties of highly stable nickel/carbon core/shell nanostructures

A simple and cost effective technique for obtaining highly stable carbon coated nickel nanostructures at relatively low reaction temperatures is reported. Thermogravimetric analysis was carried out to optimize the annealing temperatures. The powder X-ray diffraction pattern reveals peaks corresponding to face centered cubic nickel. High resolution transmission electron micrograph shows the formation of nickel nanostructures with ∼5 nm thick carbon coating. This is confirmed by Raman spectroscopy. The nickel/carbon core/shell nanostructures exhibited a shelf life of more than a year, with high thermal stability and excellent magnetic properties. This synthesis route provides scope for large scale production of nickel/carbon nanostructures.     

Benefits of low kenaf loading in biobased composites of poly(L‐lactide) and kenaf fiber

Bast fibers from stems of kenaf (Hibiscus cannabinus, L.), a warm‐season tropical herbaceous annual plant, were dispersed into poly‐L ‐lactide (PLLA) matrix by melt‐mixing followed by compression molding. Low fiber fractions (1–5%) were investigated. The composites showed a slight lowering of thermal stability when evaluated by thermogravimentric analysis. X‐ray diffraction and differential scanning calorimetry indicated an influence of kenaf on the crystallization of PLLA. The fiber dispersion in the polymer matrix was established by polarized optical microscopy. Scanning electron microscopy showed good fiber–matrix adhesion as revealed by the combination of dispersion, interaction, and crystallinity, which enabled an increase in the mechanical properties of the composite that scaled with concentration. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

An elastohydrodynamic lubrication (EHL) model of wear particle migration in an artificial hip joint

A full fluid ball-in-socket elastohydrodynamic lubrication (EHL) analysis of an artificial hip joint made of a metallic femoral head and ultra-high molecular weight polyethylene (UHMWPE) acetabular cup was considered. Since artificial hips operate in a mixed lubrication mode, wear occurs and wear particles lead to reduced hip lifetimes. This study involves simulating these particles within the lubrication regime. Hip deformation was compared to models employing finite element analysis and the spherical fast-Fourier transform technique. Particle modeling results were compared to suspension modeling experiments by other researchers. Results show a strong influence of lubricant fluid velocity on that of the wear particles.     

An evaluation framework for cross‐platform mobile application development tools

The mobile application market is becoming increasingly fragmented with the availability of multiple mobile platforms that differ in development procedures. Developers are forced to choose to support only some platforms and specific devices because of limited development resources. To address these challenges, numerous tools have been created to aid developers in building cross‐platform applications; however, there is no metric to evaluate the quality of these tools or the applications produced by them. This paper introduces a framework for evaluating the features, performance, and development experience of existing and future cross‐platform development tools. The framework is implemented by benchmarking several tools, and the results identify a disparity in the features and performance of applications built using different development tools. Copyright © 2014 John Wiley & Sons, Ltd.     

A model for investigating cultural dimensions of communication in the car

This article explicates a theoretical framework which was designed to discover cultural features both within and about car communication. The general approach the framework provides has been used for basic research in the United States and China, and has proven useful to researchers and designers. We discuss specifically how the approach can develop and implement speech-enabled human–machine interface (HMI) systems to address cultural features of communication and interaction. The general framework unveils the cultural nature of human–machine communication, while it also opens the possibility of discovering new cultural dimensions and principles which designers may not yet have considered. The approach is adaptable to a variety of communication contexts, with our focus here on the in-car communication of drivers with a speech-enabled HMI. Specific findings are briefly discussed including implications for research and design.     

Distributed Denial of Service Attacks: A Threat or Challenge

In today’s cyber world, the Internet has become a vital resource for providing a plethora of services. Unavailability of these services due to any reason leads to huge financial implications or even consequences on society. Distributed Denial of Service (DDoS) attacks have emerged as one of the most serious threats to the Internet whose aim is to completely deny the availability of different Internet based services to legitimate users. The attackers compromise a large number of Internet enabled devices and gain malicious control over them by exploiting their vulnerabilities. Simplicity of launching, traffic variety, IP spoofing, high volume traffic, involvement of numerous agent machines, and weak spots in Internet topology are important characteristics of DDoS attacks and makes its defense very challenging. This article provides a survey with the enhanced taxonomies of DDoS attacks and defense mechanisms. Additionally, we describe the timeline of DDoS attacks to date and attempt to discuss its impact according to various motivations. We highlighted the general issues, challenges, and current trends of DDoS attack technology. The aim of the article is to provide complete knowledge of DDoS attacks and defense mechanisms to the research community. This will, in turn, help to develop a powerful, effective, and efficient defense mechanism by filling the various research gaps addressed in already proposed defense mechanisms.     

Polymer supported synthesis of mixed ligand complexes

A series of novel polymer‐supported mixed ligand complexes were synthesized and studied. Two percent divinyl benzene (DVB)‐crosslinked polystyrene supports were synthesized by the suspension copolymerization technique. An ethylene diamine group was anchored onto the support and the corresponding copper complexes were prepared. The ligating functions like phthalate, acetate, and oxalate groups were introduced, and mixed ligands complexes were synthesized. The resultant polymer supported mixed ligand complexes were characterized by UV‐Vis, IR, and EPR methods. The stability constants dictate the formation of these complexes on polymer support. Spectral results gave information about the structure, stability, and geometry of the mixed ligand complexes. These factors were discussed in detail. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2684–2690, 2003     

Identifying Unknown Enzyme–Substrate Pairs from the Cellular Milieu with Native Mass Spectrometry

The enzyme–substrate complex is inherently transient, rendering its detection difficult. In our framework designed for bisubstrate systems—isotope‐labeled, activity‐based identification and tracking (IsoLAIT)—the common substrate, such as S‐adenosyl‐l ‐methionine (AdoMet) for methyltransferases, is replaced by an analogue (e.g., S‐adenosyl‐l ‐vinthionine) that, as a probe, creates a tightly bound [enzyme ? substrate ? probe] complex upon catalysis by thiopurine‐S‐methyltransferase (TPMT, EC 2.1.1.67). This persistent complex is then identified by native mass spectrometry from the cellular milieu without separation. Furthermore, the probe's isotope pattern flags even unknown substrates and enzymes. IsoLAIT is broadly applicable for other enzyme systems, particularly those catalyzing group transfer and with multiple substrates, such as glycosyltransferases and kinases.     

A fuzzy soft flood alarm model

A wide range of hydrological analyses for flood, water resources, water quality, ecological studies, etc., require reliable quantification of rainfall inputs. This work illustrates a fuzzy analysis that has the capability to simulate the unknown relations between a set of meteorological and hydrological parameters. A fuzzy approach to flood alarm prediction based on the fuzzy soft set theory is applied to five selected sites of Kerala, India to predict potential flood.     

Visualizing CH chemiluminescence in sooting flames

This investigation presents and validates a method to visualize CH^* chemiluminescence in a sooting non-premixed flame. Excited-state CH radicals (A²Δ → X²Π, denoted CH^*), upon relaxing, emit a photon in the visible portion of the electromagnetic spectrum, giving what is seen as a faint blue glow. Optical methods, especially those that rely on passive emission, provide a simple and non-intrusive means to characterize combustion; however, in the presence of hot solid particles – particularly soot – chemiluminescent emission can be obscured by blackbody radiation. This paper describes an image post-processing technique where flame emission is imaged through multiple filters near the CH^* emission band in order to infer and filter the contribution of continuum radiation from soot in the CH^* band. This information is then used to produce a soot-free image of CH^* chemiluminescence.