Heat and mass transfer behavior of unsteady flow of squeezing nanofluids between two parallel plates in the sight of uniform magnetic field with slip velocity effect is investigated. The governing equations representing fluid flow have been transformed into nonlinear ordinary differential equations using similarity transformation. The equations thus obtained have been solved numerically using Runge-Kutta-Fehlberg method with shooting technique. Effects on the behavior of velocity, temperature, and concentration for various values of relevant parameters are illustrated graphically. The skin-friction coefficient and heat and mass transfer rate are also tabulated for various governing parameters. The results indicate that, for nanofluid flow, the rates of heat and mass transfer are inversely proportional to nanoparticle volume fraction and magnetic parameter. The rate of mass transfer increases with increasing values of Schmidt number and squeeze number.

Khilap Singh

Sawan K. Rawat

Manoj Kumar

Heat and Mass Transfer on Squeezing Unsteady MHD Nanofluid Flow between Parallel Plates with Slip Velocity Effect

Titania nanotube is a well-known semiconductor and has numerous technological applications. In chemical graph theory, topological indices provide an important tool to quantify the molecular structure and it is found that there is a strong correlation between the properties of chemical compounds and their molecular structure. Among different topological indices, degree-based topological indices are most studied and have some important applications. In this study, several old and new degree-based topological indices have been investigated for titania <svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-3.181499pt" id="M1" height="11.9479pt" version="1.1" viewBox="-0.0498162 -8.7664 26.1328 11.9479" width="26.1328pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><path id="g121-82" d="M592 498C586 556 582 629 581 675H560C545 656 537 650 510 650H115C87 650 74 652 60 675H40C38 620 33 555 28 495H57C69 539 77 568 89 585C102 607 122 616 205 616H267V123C267 44 259 34 168 28V0H454V28C360 34 352 44 352 123V616H422C498 616 514 608 531 584C542 568 552 543 562 495L592 498Z"/></g><g transform="matrix(.013,0,0,-0.013,7.812,0)"><path id="g121-103" d="M135 536C164 536 186 560 186 587C186 617 164 639 136 639C109 639 85 617 85 587C85 560 109 536 135 536ZM252 0V26C188 32 181 38 181 106V451C138 433 90 420 39 412V388C99 379 102 374 102 312V106C102 38 95 32 32 26V0H252Z"/></g><g transform="matrix(.013,0,0,-0.013,11.296,0)"><path id="g121-77" d="M381 665C170 665 44 498 44 318C44 125 188 -15 369 -15C552 -15 703 117 703 333C703 534 550 665 381 665ZM359 629C491 629 601 517 601 306C601 114 502 21 390 21C249 21 146 158 146 346S248 629 359 629Z"/></g><g transform="matrix(.0091,0,0,-0.0091,21.007,3.132)"><path id="g50-51" d="M414 144C384 79 371 75 317 75H135L276 221C367 316 408 376 408 465C408 570 327 635 237 635C179 635 131 609 100 575L42 494L67 471C94 510 138 565 205 565C277 565 321 517 321 435C321 348 258 270 195 195C146 137 88 81 33 26V0H411C423 44 433 88 446 135L414 144Z"/></g></svg> nanotubes.

Nilanjan De

On Molecular Topological Properties of TiO2 Nanotubes

Refractory nanoparticles are finding broad application in manufacturing of materials with enhanced physical properties. Production of carbide, nitride, and carbonitride nanopowders in high volumes is possible in the multijet plasmachemical reactor, where temperature and velocity distributions in reaction zone can be controlled by plasma jet collision angle and mixing chamber geometry. A chemical reactor with three Direct Current (DC) arc plasma jets intersecting at one point was applied for titanium carbonitride synthesis from titanium dioxide, propane-butane mixture, and nitrogen. The influence of process operational parameters on the product chemical and phase composition was investigated. Mixing conditions in the plasma jet collision zone, particles residence time, and temperatures were evaluated with the help of Computational Fluid Dynamics (CFD) simulations. The synthesized nanoparticles have predominantly cubic shape and dimensions in the range 10&#x2013;200&#x2009;nm. Phase compositions were represented by oxycarbonitride phases. The amount of free (not chemically bonded) carbon in the product varied in the range 3&#x2013;12&#x25; mass, depending on synthesis conditions.

Michael Filkov

Andrei Kolesnikov

Plasmachemical Synthesis of Nanopowders in the System Ti(O,C,N) for Material Structure Modification

The espousal of nanotechnology is a current come-up of the present revolution. As we know that the rose aphid, Macrosiphum rosae (Hemiptera: Aphididae), is a key pest on rose plant in Kashmir Valley, India, it exhibits a worldwide distribution. In the present study, we have synthesized biologically silver nanoparticles (Ag NPs) from Solanum lycopersicum and characterized them by UV-vis spectroscopy, TEM, and X-RD analysis. The experiment was performed by leaf dip method. Insecticidal solutions of different Ag NPs concentrations, namely, 200, 300, 400, and 500&#x2009;ppm, were tested on M. rosae. For assessment purposes, leaves were treated with distilled water (used as control). Aphid mortality data revealed that the Ag NPs were effective at 500&#x2009;ppm concentration. As the concentration and day&#x2019;s treatment increased, the aphid mortality rate also increased. There were statistically significant differences in M. rosae mortality between concentrations by LSD at 5&#x25;. In wrapping up, the use of Ag NPs in pest control processes will be the most novel eco-friendly approach in the Kashmir Valley, India, in future.

Atanu Bhattacharyya

Ram Prasad

Abdul A. Buhroo

Prabha Duraisamy

Insha Yousuf

M. Umadevi

M. R. Bindhu

Marimuthu Govindarajan

Abdul L. Khanday

One-Pot Fabrication and Characterization of Silver Nanoparticles Using Solanum lycopersicum: An Eco-Friendly and Potent Control Tool against Rose Aphid, Macrosiphum rosae

The reduction in size of Zinc oxide (ZnO) and Silicon dioxide (SiO2) particles from micron to nano scale offers unique physical characteristics on one hand while making them cytotoxic on other hand. The present study was aimed at comparing cytotoxic effects of ZnO and SiO2 nanoparticles with their micron size and secondary aim was to compare responses of these particles to two different cell types, namely, human lung epithelial cells (L-132) and human monocytes (THP-1). The L-132 and THP-1 cells were exposed to nano and micron size of ZnO and SiO2 particles with different concentrations (5&#x2013;500&#x2009;&#x3bc;g/mL) for 24&#x2009;h, and cytotoxicity was analyzed by MTT assay, live-dead staining, and TC-50 was calculated. ZnO and SiO2 particles showed concentration-dependent cytotoxicity in both cell lines. In size-dependent study, ZnO particles exhibited nearly equal toxicity profile in L-132 cells while in THP-1 cells nano ZnO showed more toxicity than its micron size. The SiO2 particles showed more toxicity in their nano size than micron size in both cell lines. Human monocytes, THP-1 cells, were more sensitive towards the toxicity of both particles than human lung cells, L-132. The results highlight the difference of cytotoxicity between particle sizes and differential sensitivity of cells towards the particles of same composition. In conclusion, ZnO and SiO2 particles exhibited concentration-dependent toxicity, which was more in their nano size than micron counterpart. However, the toxic response varies depending on type of cell exposed due to differential sensitivity.

Devashri Sahu

G. M. Kannan

Mukul Tailang

R. Vijayaraghavan

In Vitro Cytotoxicity of Nanoparticles: A Comparison between Particle Size and Cell Type

Interdependency of switching voltage and time creates a dilemma/obstacle for most resistive switching memories, which indicates low switching voltage and ultra-fast switching time cannot be simultaneously achieved. In this paper, an ultra-fast (sub-100 ns) yet low switching voltage resistive switching memory device (“nanometallic ReRAM”) was demonstrated. Experimental switching voltage is found independent of pulse width (intrinsic device property) when the pulse is long but shows abrupt time dependence (“cliff”) as pulse width approaches characteristic <svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-0.2064009pt" id="M1" height="8.8423pt" version="1.1" viewBox="-0.0498162 -8.6359 16.9978 8.8423" width="16.9978pt"><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"/></g><g transform="matrix(.013,0,0,-0.013,8.151,0)"><path id="g113-68" d="M645 631C614 643 545 666 457 666C215 666 23 519 23 283C23 90 158 -16 337 -16C412 -16 489 2 522 10C543 39 590 127 606 167L580 181C519 89 459 18 348 18C201 18 122 136 122 287C122 464 244 632 435 632C544 632 602 595 608 472L639 475C643 526 645 581 645 631Z"/></g></svg> time of memory device (extrinsic device property). Both experiment and simulation show that the onset of cliff behavior is dependent on physical device size and parasitic resistance, which is expected to diminish as technology nodes shrink down. We believe this study provides solid evidence that nanometallic resistive switching memory can be reliably operated at low voltage and ultra-fast regime, thus beneficial to future memory technology.

Xiang Yang

Demonstration of Ultra-Fast Switching in Nanometallic Resistive Switching Memory Devices

This work proposes a simple method for the efficient and rapid synthesis of hematite (&#x3b1;-Fe2O3) nanostructures based on simple heating method under ambient conditions. Polyethylene glycol (PEG) is employed as a structure directing agent in driving the morphology and phase transformation. Typically, Fe2O3 nanoparticles of size below 50&#x2009;nm were synthesized at temperature around 500&#xb0;C. The morphology and mechanism of formation of the nanocapsules and then aggregation of nanocapsules to form larger size nanoclusters were studied by scanning electron microscopy and energy dispersive X-ray spectroscopy. Interestingly, this work demonstrates the structural phase transformation of hematite (&#x3b1;-Fe2O3) to maghemite (&#x3b3;-Fe2O3) upon addition of different amounts of PEG (say 0.066&#x2009;M, 0.133&#x2009;M, and 0.2&#x2009;M) and then heat treating at 500&#xb0;C. The prepared powders were used in nanoparticle paint preparation and applied as corrosion resistant coatings on iron samples. Polarization studies performed on the paint coatings made out of all the prepared samples showed size-dependent corrosion resistance. As the particle size decreases, the surface area increases and so the corrosion resistance also increases.

Pavani Katikaneani

Ajay Kumar Vaddepally

Narender Reddy Tippana

Ramu Banavath

Srivani Kommu

Phase Transformation of Iron Oxide Nanoparticles from Hematite to Maghemite in Presence of Polyethylene Glycol: Application as Corrosion Resistant Nanoparticle Paints

A facile and &#x201c;Green&#x201d; route has been applied to fabricate graphene oxide (GO) reinforced polymer composites utilizing &#x201c;deionized water&#x201d; as solvent. The GO was reinforced into water soluble poly(vinyl alcohol) (PVA) and poly-2-acrylamido-2-methyl-1-propanesulfonic acid (PAMPS) matrix by ultrasonication followed by mechanical stirring. The incorporation and dispersion of the GO in the polymer matrix were analyzed by XRD, FE-SEM, AFM, FT-IR, and TGA. Further, the FE-SEM and AFM images revealed that the surface roughness and agglomeration of the GO in the polymer matrix increased by increasing its concentration. Ionic exchange capacity, proton conductivity, and tensile texture results showed that the reinforcement of GO in the polymer matrix enhances the physicochemical properties of the host polymer. These PVA/PAMPS/GO nanocomposites showed improved mechanical stability compared to the pristine polymer, because of strong interfacial interactions within the components and homogeneous dispersion of the GO sheets in the PVA/PAMPS matrix.

R. Mahendran

D. Sridharan

K. Santhakumar

G. Gnanasekaran

Green Route Fabrication of Graphene Oxide Reinforced Polymer Composites with Enhanced Mechanical Properties

We analyzed redistribution of radiation defects in a multilayer structure with porous epitaxial layer. The radiation defects were generated during radiation processing. It has been shown that porosity of epitaxial layer gives a possibility to decrease quantity of radiation defects.

E. L. Pankratov

E. A. Bulaeva

On Relation between Porosity of Epitaxial Layer and Quantity of Radiation Defects Generated during Radiation Processing in a Multilayer Structure

Nanoimprint lithography has attracted considerable attention in academic and industrial fields as one of the most prominent lithographic techniques for the fabrication of the nanoscale devices. Effectively controllable shapes of fabricated elements, extremely high resolution, and cost-effectiveness of this especial lithographic system have shown unlimited potential to be utilized for practical applications. In the past decade, many different lithographic techniques have been developed such as electron beam lithography, photolithography, and nanoimprint lithography. Among them, nanoimprint lithography has proven to have not only various advantages that other lithographic techniques have but also potential to minimize the limitations of current lithographic techniques. In this review, we summarize current lithography techniques and, furthermore, investigate the nanoimprint lithography in detail in particular focusing on the types of molds. Nanoimprint lithography can be categorized into three different techniques (hard-mold, soft-mold, and hybrid nanoimprint) depending upon the molds for imprint with different advantages and disadvantages. With numerous studies and improvements, nanoimprint lithography has shown great potential which maximizes its effectiveness in patterning by minimizing its limitations. This technique will surely be the next generation lithographic technique which will open the new paradigm for the patterning and fabrication in nanoscale devices in industry.

B. Kwon

Jong H. Kim

Importance of Molds for Nanoimprint Lithography: Hard, Soft, and Hybrid Molds

Silver nanoparticles (AgNPs) were synthesized in skim natural rubber latex, the by-product from concentrated latex production. The role of ammonia was investigated by varying the concentration to be 0.217, 0.362, 0.377, 0.392, and 0.406 wt%. The emergence of AgNPs was detected by UV-visible spectrophotometer and electrical conductivity meter. Upon increasing ammonia concentration, the ABS peak increased to a maximum and slightly shifted to a higher wavelength and then it decreased afterward and slightly shifted to a lower wavelength. The shift of the ABS peak was consistent with the conductivity result. The kinetic model was proposed to explain the competition between the reducing effect and size-controlling effect of ammonia. The reducing effect seemed to dominate in the low range of concentration while the size-controlling effect via the formation of <svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-3.383801pt" id="M1" height="14.435pt" version="1.1" viewBox="-0.0498162 -11.0512 59.7457 14.435" width="59.7457pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><path id="g121-63" d="M673 0V28C608 34 594 43 563 129C499 303 432 494 370 665L339 656L132 132C98 43 84 37 20 28V0H238V28C162 35 154 45 175 108C188 150 203 192 219 237H432C454 176 474 122 487 83S491 36 428 28V0H673ZM418 280H234C265 362 296 450 328 535H330L418 280Z"/></g><g transform="matrix(.013,0,0,-0.013,8.813,0)"><path id="g121-101" d="M463 437C426 431 375 425 327 422C297 440 264 449 231 449H230C153 449 51 396 51 283C51 215 94 168 139 149C123 129 91 103 51 88C50 78 53 60 62 46C75 25 100 2 136 -9C112 -28 73 -59 53 -79C38 -94 29 -113 29 -135C30 -192 91 -257 203 -257C336 -257 452 -160 452 -59C452 39 371 59 309 59C275 59 240 58 203 58C158 58 140 77 140 96C140 110 157 129 170 138C186 135 205 133 221 133C306 133 396 185 396 293C396 328 384 360 366 381L423 378C439 387 459 413 468 429L463 437ZM219 418C277 418 314 362 314 284C314 205 275 166 231 165C176 165 137 221 137 299C137 376 177 418 219 418ZM241 -11C285 -11 314 -14 339 -24C367 -36 384 -61 384 -95C384 -157 335 -206 240 -206C166 -206 108 -165 108 -110C108 -82 128 -54 154 -32C172 -17 195 -11 241 -11Z"/></g><g transform="matrix(.013,0,0,-0.013,14.897,0)"><path id="g113-41" d="M300 -147C201 -63 143 98 143 270S200 602 300 686L282 710C136 610 70 450 70 271V270C70 89 136 -72 282 -170L300 -147Z"/></g><g transform="matrix(.013,0,0,-0.013,19.395,0)"><path id="g121-76" d="M719 650H483V622C553 619 576 606 581 560C585 532 588 487 588 394V148H585L167 650H20V622C67 618 88 610 109 585C127 562 129 557 129 484V264C129 173 126 124 123 93C118 44 92 31 35 28V0H272V28C204 32 181 44 176 95C173 124 170 172 170 264V515H172L598 -9H629V394C629 487 631 532 635 563C639 606 663 619 719 622V650Z"/></g><g transform="matrix(.013,0,0,-0.013,29.054,0)"><path id="g121-70" d="M729 650H468V622C546 615 554 610 554 527V365H213V527C213 610 221 616 297 622V650H38V622C120 616 128 611 128 527V123C128 39 120 34 40 28V0H303V28C221 34 213 40 213 123V322H554V123C554 39 546 34 460 28V0H728V28C647 34 639 39 639 123V527C639 610 647 615 729 622V650Z"/></g><g transform="matrix(.0091,0,0,-0.0091,39.086,3.132)"><path id="g50-52" d="M290 377C321 398 342 415 358 430C378 450 389 473 389 502C389 578 329 635 238 635H237C184 635 137 610 109 578L64 515L88 493C112 529 154 573 208 573S303 542 303 482C303 409 233 370 141 341L149 308C165 313 190 319 215 319C272 319 341 283 341 193C342 98 292 43 222 43C163 43 122 72 96 94C88 101 79 100 70 94C61 87 47 73 46 60C44 47 48 37 62 23C76 10 118 -12 165 -12C238 -12 430 62 430 223C430 297 379 359 290 375V377Z"/></g><g transform="matrix(.013,0,0,-0.013,44.032,0)"><path id="g113-42" d="M275 270C275 450 212 609 64 710L45 686C145 604 203 442 203 270S147 -63 45 -147L64 -170C213 -68 275 89 275 270Z"/></g><g transform="matrix(.0091,0,0,-0.0091,48.53,3.132)"><path id="g50-51" d="M414 144C384 79 371 75 317 75H135L276 221C367 316 408 376 408 465C408 570 327 635 237 635C179 635 131 609 100 575L42 494L67 471C94 510 138 565 205 565C277 565 321 517 321 435C321 348 258 270 195 195C146 137 88 81 33 26V0H411C423 44 433 88 446 135L414 144Z"/></g><g transform="matrix(.0091,0,0,-0.0091,53.511,-5.996)"><path id="g54-36" d="M556 236V289H337V504H275V289H56V236H275V-4H337V236H556Z"/></g></svg> complex ion was important in the higher range. The TEM figures evidently confirmed the effects.

Panu Danwanichakul

Thanawat Suwatthanarak

Chidchanok Suwanvisith

Duangkamol Danwanichakul

The Role of Ammonia in Synthesis of Silver Nanoparticles in Skim Natural Rubber Latex

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Journal of Nanoscience