Smart,lightweight, flexible NiO/poly(vinylidene flouride) nanocomposites film with significantly enhanced dielectric,piezoelectric and EMI shielding properties

We report a facile technique to fabricate flexible and self-standing NiO/PVDF nanocomposite films. Detail structural and thermal characterizations of nanocomposite films show the gradual increase of electroactive β-phase of PVDF with increasing NiO nanoparticles content. The enhancement of β phase in the NiO/PVDF nanocomposites has been explained from physicochemical point of view. Electrical properties of the nanocomposites indicate fair improvement in dielectric properties at low filler loading with less dielectric loss. The value of dielectric constant of 0.75 wt% NiO/PVDF films at 100 Hz is five times higher than that of neat PVDF. Series-parallel model was used to describe the filler concentration dependence of the dielectric constant of the nanocomposites. These nanocomposites also exhibit excellent ferroelectric properties. Nanocomposite films having thickness 300 μm were also successfully employed for microwave shielding application. This work suggests that these films would be very useful for thinner, lighter energy harvesting storage and EMI shielding applications.     

Exploring the modelling and simulation knowledge base through journal co-citation analysis

Co-citation analysis is a form of content analysis that can be applied in the context of scholarly publications with the purpose of identifying prominent articles, authors and journals being referenced to by the citing authors. It identifies co-cited references that occur in the reference list of two or more citing articles, with the resultant co-citation network providing insights into the constituents of a knowledge domain (e.g., significant authors and papers). The contribution of the paper is twofold; (a) the demonstration of the added value of using co-citation analysis, and for this purpose the underlying dataset that is chosen is the peer-reviewed publication of the Society for Modeling and Simulation International (SCS)—SIMULATION; (b) the year 2012 being the 60th anniversary of the SCS, the authors hope that this paper will lead to further acknowledgement and appreciation of the Society in charting the growth of Modeling and Simulation (M&S) as a discipline.     

Profiling a decade of Information Systems Frontiers’ research

This article analyses the first 10 years of research published in the Information Systems Frontiers (ISF) from 1999 to 2008. The analysis of the published material includes examining variables such as most productive authors, citation analysis, universities associated with the most publications, geographic diversity, authors’ backgrounds and research methods. The keyword analysis suggests that ISF research has evolved from establishing concepts and domain of information systems (IS), technology and management to contemporary issues such as outsourcing, web services and security. The analysis presented in this paper has identified intellectually significant studies that have contributed to the development and accumulation of intellectual wealth of ISF. The analysis has also identified authors published in other journals whose work largely shaped and guided the researchers published in ISF. This research has implications for researchers, journal editors, and research institutions.

A comparative assessment of poly(vinylidene fluoride)/conducting polymer electrospun nanofiber membranes for biomedical applications

Piezoelectric polymers, especially poly(vinylidene fluoride) (PVDF) are increasingly receiving interest as smart biomaterials for tissue engineering, energy harvesting, microfluidic, actuator, and biosensor applications. Despite possessing the greatest piezoelectric coefficients among all piezoelectric polymers, it is often desirable to increase the electrical outputs from PVDF for several of these applications. Blending with intrinsically conducting polymers (CP) in the form of nanofiber membranes is one of the facile methods to achieve the same. However, these polymers and their composites have so far been primarily investigated only for their physical property enhancements and in applications like energy storage while their biomedical applications and comparative assessment of their biocompatibility properties have not been yet explored. In this report, electrospinning of PVDF blends with polypyrrole (PPy), polyaniline (PANI), and a modified PANI with l -glutamic acid (PANI-LGA/P-LGA) is performed to obtain different electrically active material membranes. The PVDF:CP composite nanofibers are compared with respect to their nanostructures, β-phase content, and electrical conductivity. Further, biocompatibility of all the membranes was compared. It was found that incorporation of PPy, PANI, and P-LGA increased the electrical conductivity of PVDF while the β-phase content was also substantially enhanced. The highest biocompatibility with a pre-osteoblast cell line (MC3T3) was exhibited in the order p-LGA/PVDF > PANI/PVDF > PPy/PVDF, all being significantly higher than PVDF (p < .001). Although P-LGA/PVDF showed higher electrical conductivity, biocompatibility with MC3T3, it was found to be highly cytotoxic to a HeLa (cancer) cell line. It is concluded that such structure property relations would help in selection of materials for specific biomaterial applications.     

Speeding up systems biology simulations of biochemical pathways using condor

Systems biology is a scientific field that uses computational modelling to study biological and biochemical systems. The simulation and analysis of models of these systems typically explore behaviour over a wide range of parameter values; as such, they are usually characterised by the need for nontrivial amounts of computing power. Grid computing provides access to such computational resources. In previous research, we created the grid‐enabled biochemical networks simulation environment to attempt to speed up system biology simulations over a grid (the UK National Grid Service and ScotGrid). Following on from this work, we have created the simulation modelling of the epidermal growth factor receptor microtubule‐associated protein kinase pathway utility, a standalone simulation tool dedicated to the modelling and analysis of the epidermal growth factor receptor microtubule‐associated protein kinase pathway. This builds on experiences from biochemical networks simulation environment by decoupling the simulation modelling elements from the Grid middleware. This new utility enables us to interface with different grid technologies. This paper therefore describes the new SIMAP utility and an empirical investigation of its performance when deployed over a desktop grid based on the high throughput computing middleware Condor. We present our results based on a case study with a model of the mammalian ErbB signalling pathway, a pathway strongly linked to cancer. Copyright © 2013 John Wiley & Sons, Ltd.     

Temperature dependent dielectric properties of self‐standing and flexible poly(vinylidene fluoride) films infused with Er3+ doped GeO2 and SiO2 nanoparticles

The synthesis of Er³⁺@GeO₂ and Er³⁺@SiO₂ nanoparticle impregnated self‐standing poly(vinylidene fluoride) films by a facile solution casting technique has been reported. The prepared films were thoroughly characterized using X‐ray diffraction technique, field emission scanning electron microscopy, and transmission electron microscopy. The optical properties were evaluated using UV–Vis spectroscopy. Detailed study on the temperature dependent dielectric properties of the composite films with different Er³⁺ content were also investigated to establish the electrical properties of the same, which revealed the presence of different relaxation processes, namely, and ρ. Due to the smaller size, Er³⁺@SiO₂ was found to disperse better in the PVDF matrix than Er³⁺@GeO₂, which resulted in higher dielectric constant of the former at 300 K. At higher temperature (403 K), the behavior was reversed due to the formation of larger sized low mobility complexes. An investigation on ac conductivity proved the conduction mechanism for neat as well as composite PVDF films to follow the Correlated Barrier Hopping model. The loading of Er³⁺@GeO₂ and Er³⁺@SiO₂ nanoparticles in the PVDF matrix significantly enhances the dielectric properties without losing the flexibility of the composite films. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44016.     

Motivations and barriers in using distributed supply chain simulation

Discrete event simulation (DES) is a technique that is used by analysts to take informed decisions regarding an existing or proposed system of interest. DES models typically represent the processes associated with various business units. However, in the case of supply chains more than one business unit may need to be modelled as different organisations may be responsible for various supply chain operations such as manufacturing, transport and logistics, distribution, warehouse operations, etc. Organisations can be protective about their internal processes and can have concerns regarding data/information security and privacy. Thus it could be argued that creating a single DES supply chain model representing the various inter‐organisational processes is usually not an option since this will run counter to organisational privacy. Further, issues such as data transfer, model composability and execution speed may also make a single model approach problematic. A potential solution could be to create several distinct and well‐defined DES models, each modelling the processes associated with one specific supply chain business unit, linked together over the internet. We refer to this possible distributed approach as Distributed Supply Chain Simulation (DSCS). Although this approach holds great promise, there are technical barriers in using DSCS. The paper discusses the benefits and barriers of a distributed approach and then, using a healthcare DSCS, the technological feasibility is demonstrated. In conclusion, the paper argues that adopting a standardised approach to DSCS will remove a major barrier to its use.     

Study of optical properties of GeO2 nanocrystals as synthesized by hydrothermal technique

The GeO₂ nanocrystals (α-quartz type structure) with β-phase are synthesized at relatively lower temperature by hydrothermal route using autoclave. All samples are characterized by XRD, FESEM, EDS, TEM, photoluminescence (PL) and UV–vis absorption spectroscopy techniques. Synthesized nanocrystals have uniform shape and uniform size distribution for a particular synthesis condition, which is about 30–300 nm depending on synthesis conditions. The XRD results indicate that grown GeO₂ crystals only shows peak related to α-quartz structure with lattice parameters a = 4.985 Å and c = 5.648 Å. UV–vis absorption spectroscopy measurements reveal the bandgap energies corresponding to the GeO₂ α-quartz structure. Synthesized nanocrystals are capable to emit strong blue light around 425–435 nm under excitation of 300 nm and 325 nm and consequently the as synthesized material can be used in integrated optical devices.     

Analysing trade‐offs in container loading: combining load plan construction heuristics with agent‐based simulation

In this paper we describe two operations research techniques, cutting and packing optimisation (CPO) and simulation, and present a multi‐methodology approach for analysing the trade‐offs between loading efficiency and various important practical considerations in relation to the cargo, such as its stability, fragility or possible cross‐contamination between different types of items over time. The feasibility of this approach is demonstrated by considering a situation where the items to be loaded have differing degrees of perishability and where badly deteriorated items can affect those in their immediate vicinity (e.g. through the spread of mould). Our approach uses the output of the CPO algorithms to create agents that simulate the spread of mould through proximity‐based interactions between the agents. The results show the trade‐offs involved in container utilisation and the propagation of mould, without evidence of any correlation between them. The contribution of this research is the methodology and the feasibility study.