A Concise Account on the Properties of CNT-Reinforced Epoxy Composites based on some Select References

Recently it has been reported in the technical literature that carbon nanotubes (CNTs) have distinct effects on thermal, mechanical and electric properties of epoxy resins. Compared to single-walled nanotubes (SWCNT), multiwalled nanotubes (MWCNT) apparently show greater improvements. The maximum aspect ratio (L/D) of CNT is reportedly as high as 138,000,000. In addition, the carbon nanotubes when treated with surface modifier to generate functional groups on their surface can afford to provide better improvement of the properties of the epoxy based CNT-particulate composite system. There are a number of factors that can influence the properties of epoxy-CNT systems. This paper examined the technical contents from selective references and made an attempt to highlight the general understanding of the properties and performance of epoxy – CNT particulate composite systems.Defence Science Journal, Vol. 64, No. 3, May 2014, pp.303-308, DOI:http://dx.doi.org/10.14429/dsj.64.7330

A Self-Similar Sine-Cosine Fractal Architecture for Multiport Interferometers

Multiport interferometers based on integrated beamsplitter meshes have recently captured interest as a platform for many emerging technologies. In this paper, we present a novel architecture for multiport interferometers based on the Sine-Cosine fractal decomposition of a unitary matrix. Our architecture is unique in that it is self-similar, enabling the construction of modular multi-chiplet devices. Due to this modularity, our design enjoys improved resilience to hardware imperfections as compared to conventional multiport interferometers. Additionally, the structure of our circuit enables systematic truncation, which is key in reducing the hardware footprint of the chip as well as compute time in training optical neural networks, while maintaining full connectivity. Numerical simulations show that truncation of these meshes gives robust performance even under large fabrication errors. This design is a step forward in the construction of large-scale programmable photonics, removing a major hurdle in scaling up to practical machine learning and quantum computing applications.Comment: 8 pages, 5 figure

Brown coal dewatering using poly (Acrylamide-co-potassium acrylic) based super absorbent polymers

With the rising cost of energy and fuel oils, clean coal technologies will continue to play an important role during the transition to a clean energy future. Victorian brown coals have high oxygen and moisture contents and hence low calorific value. This paper presents an alternative non evaporative drying technology for high moisture brown coals based on osmotic dewatering. This involves contacting and mixing brown coal with anionic super absorbent polymers (SAP) which are highly crossed linked synthetic co-polymers based on a cross-linked copolymer of acryl amide and potassium acrylate. The paper focuses on evaluating the water absorption potential of SAP in contact with 61% moisture Loy Yang brown coal, under varying SAP dosages for different contact times and conditions. The amount of water present in Loy Yang coal was reduced by approximately 57% during four hours of SAP contact. The extent of SAP brown coal drying is directly proportional to the SAP/coal weight ratio. It is observed that moisture content of fine brown coal can readily be reduced from about 59% to 38% in four hours at a 20% SAP/coal ratio. © 2015 by the authors; licensee MDPI, Basel, Switzerland

Quantitative Analysis of Curing Mechanisms of Epoxy Resin by Mid- and Near- Fourier Transform Infra Red Spectroscopy

This article informs the essence of major work done by a number of researchers on the analysis of two-step curing mechanism of diglycidyl ether of bisphenol A (DGEBA) epoxy resin in presence of amine curing agents using near- and mid-IR technology. Various peaks used as a marker for resin formation are discussed and their implementation is comprehensively studied. In addition to this, a wide range of information about the importance of reference peaks in both near-IR (NIR) and mid-IR (MIR) regions are congregated and their accuracy is audited. Also discrepancies observed by researchers in epoxy conversion (α) in NIR and MIR regions are reviewed to highlight the comparative advantages of both regions, one over the other.Defence Science Journal, Vol. 64, No. 3, May 2014, pp. 314-321, DOI:http://dx.doi.org/10.14429/dsj.64.732

SEM study of debonding /pull-out features & FTIR analysis of bonding in fly ash- epoxy particulate composites

This research utilises as received coal power fly ash (FA) as a value-added component added to epoxy resin for making a superior matrix for fibre reinforced composites in load-bearing applications. The epoxy resin used in this project was DGEBA cured by cycloaliphatic polyamine at 120 Co for 2 hours. A fly ash with particle size ranging between 2 – 20 micron was added to the epoxy in 0, 10, 20, 30, 40 & 50 wt% proportions. Scanning Electron Microscopy (SEM) of tensile fracture surfaces of the composites using ASTM D638 tensile samples provide significant evidence of Fly Ash debonding and pull-out from the epoxy matrix indicating good mechanical bonding between FA and epoxy matrix. Fourier transform infrared spectroscopy (FTIR) of pure epoxy, pure fly ash and selective composites (20 and40 wt % FA-epoxy composites) shows distinct evidence of fly ash functional groups’ interaction with the epoxy matrix. Some selected SIMS (secondary ion mass spectrometry) results are presented for the 20wt % fly ash /epoxy composites

Use of Secondary Ion Mass Spectrometry (SIMS) to identify fly ash mineral spatial and particulate distribution in epoxy polymer

Fly ash from coal power stations consists typically of a series of oxide minerals. These minerals can have beneficial effects when used as reinforcement in a plastic matrix. In this work the advanced technique SIMS has been utilised to identify the spatial distribution of the various minerals in fly ash in an epoxy matrix with fly ash weights of 10% and 50%. It is observed that SIMS, which can scan normally to a precision of 0.5 to 0.05 wt.%, could positively identify the distribution of the fly ash mineral elements in the epoxy. Attempts were also made to identify the fly ash element distribution in the epoxy using a composition analysis method, namely, EDS. However, it is observed that in the present fly ash-epoxy composites, EDS could not identify the fly ash elements demonstrating SIMS is a much preferred identification technique than the popular EDS method. © 2015 Elsevier B.V. All rights reserved