Defence Applications of Polymer Nanocomposites

The potential opportunities promised by nanotechnology for enabling advances in defence technologies are staggering. Although these opportunities are likely to be realised over a few decades, many advantages are currently being explored, particularly for defence applications. This review provides an insight into the capabilities offered by nanocomposites which include smart materials, harder/lighter platforms, new fuel sources and storage as well as novel medical applications. It discusses polymer-based nanocomposite materials, nanoscale fillers and provides examples of the actual and potential uses of nanocomposite materials in defence with practical examples.Defence Science Journal, 2010, 60(5), pp.551-563, DOI:http://dx.doi.org/10.14429/dsj.60.57

Influence of cu addition on the wear behavior of a eutectic Al–12.6Si alloy developed by the spray forming method

first_pagesettingsOrder Article Reprints Open AccessArticle Influence of Cu Addition on the Wear Behavior of a Eutectic Al–12.6Si Alloy Developed by the Spray Forming Method by Dayanand M. Goudar 1,Julfikar Haider 2ORCID,K. Raju 3,Rajashekar V. Kurahatti 4 andDeesy G. Pinto 5,6,* 1 Department of Mechanical Engineering, Tontadarya College of Engineering, Gadag 582101, India 2 Department of Engineering, Manchester Metropolitan University, Manchester M15GD, UK 3 Department of Mechanical Engineering, St. Joseph Engineering College, Mangaluru 575028, India 4 Department of Mechanical Engineering, Basaveshwar Engineering College, Bagalkot 587101, India 5 Department of Civil Engineering and Geology, University of Madeira, Campus da Penteada, 9020-105 Funchal, Portugal 6 CQM-Centro de Química da Madeira, University of Madeira, Campus da Penteada, 9020-105 Funchal, Portugal * Author to whom correspondence should be addressed. J. Compos. Sci. 2024, 8(3), 88; https://doi.org/10.3390/jcs8030088 Submission received: 19 January 2024 / Revised: 9 February 2024 / Accepted: 23 February 2024 / Published: 27 February 2024 (This article belongs to the Special Issue Metal Composites, Volume II) Downloadkeyboard_arrow_down Browse Figures Versions Notes Abstract In the present study, the influence of the addition of copper (Cu) on the wear behavior of a Al-12.6Si eutectic alloy developed using the spray forming (SF) method was discussed, and the results were compared with those of as-cast (AC) alloys. The microstructural features of the alloys were examined using both optical and the scanning electron microscopy, and the chemical composition and phase identification were achieved by X-ray diffraction (XRD) analysis. The results revealed that the microstructure of binary the SF alloy consisted of fine primary and eutectic Si phases, evenly distributed in the equiaxed α-Al matrix, whereas the Cu-based SF ternary alloy consisted of uniformly distributed fine eutectic Si particulates and spherical-shaped θ-Al2Cu precipitates, uniformly distributed in α-Al matrix. In contrast, the AC ternary (Al-12.6Si-2Cu) alloy consisted of unevenly dispersed eutectic Si needles and the coarse intermetallic compound θ-Al2Cu in the α-Al matrix. The addition of Cu enhanced the micro hardness of the SF ternary alloy by 8, 34, and 41% compared to that of the SF binary, AC ternary, and binary alloys, respectively. The wear test was conducted using a pin-on-disc wear testing machine at different loads (10–40 N) and sliding velocities (1–3 ms−1). The wear tests revealed that SF alloys exhibited an improved wear behavior in the entire applied load and sliding velocity range in comparison to that of the AC alloys. At a load of 40 N and a sliding velocity of 1 ms−1, the wear rate of the SF2 alloy is 62, 47, and 23% lower than that of the AC1, AC2, and SF1 alloys, respectively. Similarly, at a sliding velocity of 3 ms−1, the wear rate of the SF2 alloy is 52%, 42%, and 21% lower than that of the AC1, AC2, and SF1 alloys, respectively. The low wear rate in the SF2 alloy was due to the microstructural modification during spray forming, the precipitation of fine Al2Cu intermetallic compounds, and increased solid solubility. The SF alloys show an increased transition from oxidative to abrasive wear, while the AC alloys demonstrate wear mechanisms that change from oxidative to abrasive, including delamination, with an increase in sliding velocity and load

Polyethylene/Polyhydroxyalkanoates-based Biocomposites and Bionanocomposites

The development of advanced polymer composite materials having superior mechanical properties has opened up new horizons in the field of science and engineering. Polyethylene (PE) is considered one of the most widely used thermoplastics in the world due to its excellent properties which have excellent chemical inertness, low coefficient of friction, toughness, near-zero moisture absorption, ease of processing and electrical properties. Polyhydroxyalkanoates (PHAs) are garnering increasing attention in the biodegradable polymer market because of their promising properties such as high biodegradability in different environments. This chapter covers polyethylene/polyhydroxyalkanoates-based biocomposites and bionanocomposites. It summarizes many of the recent research accomplishments in the area of PE/PHAs-based biocomposites and bionanocomposites such as state-of-the-art regarding different methods of their preparation. Also discussed are different characterization techniques and use of PE/PHAs-based biocomposites and bionanocomposites in biomedical, packaging, structural, military, coating, fire retardant, aerospace and optical applications, along with recycling and lifetime studies

Review on conceptual study of Jara Laxanas mentioned in Brihatrayee

The present study reveals that the process of ageing was elaborately described in Ayurveda. Ayurveda, the science of life covers a wide range of subjects and issues of living beings in relation to total approaches of individual development and health care. Different Samhita in Ayurveda gives detail knowledge about signs and symptoms which appears in old age including primitive, preventive and curative aspect of health sciences. Jara management in present time is a challenging task for present health providing system. Our Aptas knowledge helps to overcome from these through Rasayana Chikitsa

Review on conceptual study of Jara Avastha mentioned in Brihatrayee

Vaya, which means Age, represents state of body depending upon the length of time that has passed since birth of a human being. Considering a total life span of 100 years, Acharya Charaka and Sushrutha has described old age after 60 years and 70 years respectively. The present study reveals that the process of ageing was elaborately described in Ayurveda. In order to prolong the life span and to promote longevity a separate discipline called Rasayana Tantra was developed. The silent features of this study are described in this article

Building an Institutional Repository: A TIFR Initiative

Abstract Building an Institutional Repository has twin objectives. It servers as a digital archive of the total research output created by the academic community of an institute. It makes freely accessible over the internet this intellectual output to all those who are interested in it, thereby promoting the knowledge development. TIFR too is therefore planning to build its Institutional Repository and as a prelude to this has undertaken a pilot project. This paper discusses some of the details of this initiative

Monolithic surface acoustic wave resonator oscillator

A monolithic surface acoustic wave (SAW) resonator operating at 156 MHz, in which the frequency controlling element is a Fabry–Perot type of SAW resonator and the gain element is a monolithic SAW amplifier (SiOx/InSb/SiOx structure located inside the SAW resonator cavity) is described and experimental details presented. Based on the existing experimental data, an uhf monolithic ring resonator oscillator is proposed. Journal of Applied Physics is copyrighted by The American Institute of Physics