A nonlocal elastic shell model considering the small scale effects is developed to study the free vibrations of multiwalled carbon nanotubes subject to different types of boundary conditions. Based on the nonlocal elasticity and the Fl&#xfc;gge shell theory, the governing equations are derived which include the interaction of van der Waals forces between adjacent and nonadjacent layers. To analytically solve the problem, the Rayleigh-Ritz method is employed. In the present analysis, different combinations of layerwise boundary conditions are taken into account. Some new intertube resonant frequencies and the associated noncoaxial vibrational modes are identified owing to incorporating circumferential modes into the shell model.

H. Rouhi

M. Bazdid-Vahdati

R. Ansari

Rayleigh-Ritz Vibrational Analysis of Multiwalled Carbon Nanotubes Based on the Nonlocal Fl&#xfc;gge Shell Theory

The present paper reports phase, microstructure, and compressive strength of ZrO2 reinforced Fe Metal Matrix Nanocomposites (MMNCs) synthesized by powder metallurgy (P/M) technique. High purity grade iron metal powder was mixed with varying percentage of zirconium dioxide (5&#x2013;30&#x2009;wt&#x25;), compacted, and sintered in argon atmosphere in the temperature range of 900&#x2013;1100&#xb0;C for 1 to 3 hours. X-ray diffraction (XRD) analysis of specimens was done in order to study the phases present and scanning electron microscopy was carried out to determine the morphology and grain size of the various constituents. XRD result shows the presence of Fe, ZrO2, and Zr6Fe3O phase. Zr6Fe3O phase forms due to reactive sintering and is not reported earlier by researchers throughout the globe. SEM results showed the presence of dense microstructure with the presence of Fe, ZrO2, and some nanosize Zr6Fe3O phases.

Pushkar Jha

Pallav Gupta

Devendra Kumar

Om Parkash

Effect of Sintering Mechanism on the Properties of ZrO2 Reinforced Fe Metal Matrix Nanocomposite

Electrically conductive woven, knitted, and nonwoven composite fabrics are prepared by in situ chemical polymerization of pyrrole using suitable oxidant and dopant. These composite fabrics show surface resistivity in the range  &#x7e;1 to 2&#x2009;k&#x2126;. These composite fabric can alter their resistivity with various stimuli such as mechanical strain, pH, and humidity. So, in the present study, their response to pH, humidity, and mechanical strain is investigated. For all fabrics, similar behaviour has been observed regarding pH versus resistivity. The resistance of the composite fabric increases with the increase of alkalinity of pH. However, as bending strain increases, resistance steeply decreases for cotton fabrics, steeply increases for polyester fabrics, and initially decreases and then increases for wool fabrics. Regarding humidity sensitivity, sigmoid curves have been obtained for all kinds of fabrics.

Subhankar Maity

Arobindo Chatterjee

Textile/Polypyrrole Composites for Sensory Applications

In this preliminary investigation, dolomite was added to the low-density polyethylene/kenaf core fiber (LDPE/KCF) biocomposites by using an internal mixer at 150&#xb0;C, followed by compression molding at the same temperature. The dolomite contents were varied from 0 to 18&#x2009;wt.&#x25;. The processing and stabilization torques, the stock and stabilization temperatures, the tensile and impact strengths, and the thermal decomposition properties of the prepared biocomposites have been characterized and analyzed. The processing recorder results of the LDPE/KCF biocomposites indicated that the stabilization torques and stabilization temperatures have increased with the addition of dolomite. Mechanical testing results showed that the presence of dolomite has increased the tensile stress, tensile modulus, and impact strength of the LDPE/KCF biocomposites. Thermogravimetric analysis results displayed that the thermal decomposition properties of the biocomposites have also increased with the increase of the dolomite content. This research led to the conclusion that the addition of dolomite in lower amounts (&#x3c;20&#x2009;wt.&#x25;) could act as a secondary filler for improving the processing, mechanical and thermal properties of LDPE/KCF biocomposites without surface treatments of the natural fiber.

Ahmad Adlie Shamsuri

Mohammad Naqiuddin Mohd Zolkepli

Azmah Hanim Mohamed Ariff

Ahmad Khuzairi Sudari

Mazni Abu Zarin

A Preliminary Investigation on Processing, Mechanical and Thermal Properties of Polyethylene/Kenaf Biocomposites with Dolomite Added as Secondary Filler

Abrasive waterjet machining (AWJM) is an emerging machining process in which the material removal takes place due to abrasion. A stream of abrasive particles mixed with filtered water is subjected to the work surface with high velocity. The present study is focused on the experimental research and evaluation of the abrasive waterjet machining process in order to evaluate the technological factors affecting the machining quality of CFRP laminate using response surface methodology. The standoff distance, feed rate, and jet pressure were found to affect kerf taper, delamination, material removal rate, and surface roughness. The material related parameter, orientation of fiber, has been also found to affect the machining performance. The kerf taper was found to be 0.029 for 45° fiber orientation whereas it was 0.036 and 0.038 for 60° and 90°, respectively. The material removal rate is 18.95 mm3/sec for <svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-0.2064009pt" id="M1" height="11.0031pt" version="1.1" viewBox="-0.0498162 -10.7967 16.6412 11.0031" width="16.6412pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><path id="g113-53" d="M456 178V225H360V632H320C217 496 115 347 20 206V178H280V106C280 40 276 34 189 27V0H445V27C364 34 360 39 360 106V178H456ZM280 225H82C149 335 214 431 278 520H280V225Z"/><glyph.data ascent="3473" descent="-2876" horiz-adv-x="480" vert-adv-y="480"/></g><g transform="matrix(.013,0,0,-0.013,6.24,0)"><path id="g113-54" d="M153 550H386L412 615L406 623H120L82 318C104 327 142 338 184 338C294 338 347 275 347 187C347 112 305 39 221 39C160 39 119 71 97 89C88 97 80 96 71 90C59 80 50 67 49 57C48 45 52 36 66 23C80 9 123 -12 169 -12C221 -11 288 15 342 59C403 109 431 165 431 225C431 308 366 395 238 395C212 395 165 379 127 364L153 550Z"/><glyph.data ascent="3473" descent="-2876" horiz-adv-x="480" vert-adv-y="480"/></g><g transform="matrix(.0091,0,0,-0.0091,12.527,-5.741)"><path id="g54-73" d="M339 262C339 340 273 403 193 403S48 340 48 262S113 121 193 121S339 184 339 262ZM283 262C283 210 242 168 193 168S104 210 104 262S144 356 193 356S283 314 283 262Z"/><glyph.data ascent="3443" descent="-2856" horiz-adv-x="385" vert-adv-y="385"/></g></svg> fiber orientation compared to 18.26 mm3/sec for 60° and 17.4 mm3/sec for 90° fiber orientation. The <svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-3.291101pt" id="M2" height="11.927pt" version="1.1" viewBox="-0.0498162 -8.6359 13.409 11.927" width="13.409pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><path id="g113-83" d="M610 18C585 26 567 34 540 68C517 97 499 128 476 171C452 215 425 276 413 304C496 332 570 394 570 494C570 555 545 595 509 619S419 650 364 650H139L133 622C216 615 219 612 203 527L129 132C112 40 105 36 23 28L17 0H279L285 28C199 34 194 40 211 132L239 284H284C320 284 334 275 351 236C374 182 394 140 420 93C459 23 495 -1 592 -8H600L610 18ZM480 485C480 424 449 372 403 342C374 323 338 316 293 316H245L291 562C296 589 301 601 311 608S337 618 358 618C432 618 480 575 480 485Z"/><glyph.data ascent="3473" descent="-2876" horiz-adv-x="627" vert-adv-y="627"/></g><g transform="matrix(.0091,0,0,-0.0091,8.086,3.132)"><path id="g50-98" d="M490 97L476 124C442 96 405 70 398 70C392 70 390 78 396 114C419 243 448 379 463 432L457 436C446 436 431 439 418 442C393 447 368 451 343 451C281 451 204 418 155 381C74 320 24 206 24 107C24 23 59 -12 88 -12C118 -12 155 5 191 34C236 70 290 122 328 177H330L312 84C296 0 311 -12 331 -12C355 -12 425 24 490 97ZM374 387C371 367 360 299 347 264C323 202 187 53 142 53C128 53 113 73 113 120C113 224 157 332 221 380C241 395 274 403 303 403C330 403 360 395 374 387Z"/><glyph.data ascent="3443" descent="-2856" horiz-adv-x="514" vert-adv-y="514"/></g></svg> value for 45° fiber orientation is 4.911 µm and for 60° and 90° fiber orientation it is 4.927 µm and 4.974 µm, respectively. Delamination factor is found to be more for 45° fiber orientation, that is, 2.238, but for 60° and 90° it is 2.029 and 2.196, respectively.

Prasad D. Unde

M. D. Gayakwad

N. G. Patil

R. S. Pawade

D. G. Thakur

P. K. Brahmankar

Experimental Investigations into Abrasive Waterjet Machining of Carbon Fiber Reinforced Plastic

A full biocomposite was fabricated from Cordenka CR fibre and furan resin. High fibre mass fractions (FMF) were achieved by pressing the CR fibres into unidirectional sheets prior to incorporation into the resin. Results of testing indicated that the tensile properties of the biocomposite were improved by the initial increase of FMF from 51 to 64&#x25;, with a subsequent increase of FMF to 75&#x25; resulting in a deterioration of those properties. Examination of the tensile fracture surfaces with a scanning electron microscope (SEM) revealed moderate deterioration in fibre-matrix adhesion after the initial increase of FMF. Further increase of the FMF to 75&#x25; was shown by SEM to result in worse fibre-matrix adhesion. On the other hand, the flexural, interlaminar-shear, and dynamic mechanical properties were adversely affected by the increase in fibre-mass fraction from 51 through 75&#x25;. These effects were mainly attributed to reduced fibre wetting that resulted in weakened fibre-matrix interfacial bonding and subsequent poor stress exchange at the fibre-matrix interface. Observations made with a digital microscope revealed normal crack behaviour in the laminated composite, and the shear fracture modes were I and II. This biocomposite has mechanical properties comparable to those of flax and glass fibre-reinforced furan resin biocomposites.

Talent Malaba

Jiajun Wang

Unidirectional Cordenka Fibre-Reinforced Furan Resin Full Biocomposite: Properties and Influence of High Fibre Mass Fraction

Composites have monopolized the automotive, construction, and packaging industry. Their high strength to weight ratio has made them an integral part of numerous engineering applications. In this study biodegradable matrix is combined with areca frond fibres for developing composites for low strength structural applications. Areca frond fibres were extracted and treated with sodium bicarbonate to improve the surface characteristics. Hand lay-up and compression moulding techniques were used to fabricate composites having unidirectional fibre orientation. The specimens prepared were exposed to varied environments, namely, sunlight, OTG oven, steam oven, and hot air oven, for curing and the results were analyzed to best suit the implicated requirements. Scanning electron microscopy was used to observe the changes in surface characteristics of the frond fibres after treatment. Tensile and flexural strength of starch based/areca frond reinforced composites were evaluated according to ASTM standards. Test results revealed that composites cured in a steam oven resulted in improved tensile and flexural strength compared to other curing environments.

Srinivas Shenoy Heckadka

Suhas Yeshwant Nayak

Manjeshwar Vijaya Kini

Revati Chowgule

Pranay Jain

Effect of Curing on the Tensile and Flexural Performance of Fully Biodegradable Corn Starch/Areca Frond Composites

Mohamed S. Aly-Hassan

Elsayed A. Elbadry

Hiroyuki Hamada

Corrigendum to &#x201C;Agro-Residues: Surface Treatment and Characterization of Date Palm Tree Fiber as Composite Reinforcement&#x201D;

Oriented strand board (OSB) is an important wood composite used in situations where fungal decay and termite attack can occur. To counter these threats, powdered zinc borate biocide is commonly added to OSB. The effectiveness of biocides depends on their even distribution within composites and resistance to leaching, but little is known about the distribution of zinc borate in OSB. Zinc is denser than wood and it should be possible to map its distribution in OSB using X-ray micro-CT. We test this hypothesis and chemically register zinc in OSB using SEM-EDX. Zinc borate particles aggregated at the wood-adhesive interface in OSB, creating interrupted lines of zinc oriented in the x-y plane. Zinc borate particles were also found in the lumens of wood cells. Zinc was distributed throughout OSB, although slightly less was present in the core of the composite than in surface layers. A network of zinc remained in OSB after leaching in water. The resistance of zinc to leaching may be due to its incorporation in glue-lines within OSB, in addition to its low water-solubility. We conclude that X-ray micro-CT is a powerful tool for studying the distribution of zinc in OSB and other wood composites containing zinc borate.

Philip D. Evans

Vinicius Lube

Holger Averdunk

Ajay Limaye

Michael Turner

Andrew Kingston

Timothy J. Senden

Visualizing the Microdistribution of Zinc Borate in Oriented Strand Board Using X-Ray Microcomputed Tomography and SEM-EDX

Nickel powders were troweled on roughened Al base plate using a friction tool made
from tool steel. Friction stir processing (FSP) was carried out using a load of 8&#x2009;kN and with a
tool rotation speed of 800&#x2009;rpm and thus a surface composite was processed. Processed samples
were characterized for revealing the microstructural features. SEM and XRD analysis revealed
the presence of fine Ni particles in the stir zone which lead to a significant increase in hardness. Using the &#x201c;refined energy model,&#x201d; the maximum temperature developed within the processed
zone was estimated and found to be around 275&#xb0;C. Impression creep behaviour was assessed
on both the base metal and processed zone at the temperature of 30, 100, and 200&#xb0;C. Creep
curves were generated and steady state creep rate (SSCR) values were found out to determine the
activation energy. It is observed that friction stirred regions record higher creep rate values
compared to the base metal. Estimated activation energy is in the range of 6 to 16&#x2009;kJ/mol. Activation energy is marginally lower in the base metal compared to friction stir processed region.

Prakrathi Sampath

Vineeth Krishna Parangodath

Kota Rajendra Udupa

Udaya Bhat Kuruveri

Fabrication of Friction Stir Processed Al-Ni Particulate Composite and Its Impression Creep Behaviour

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Journal of Composites