Key Engineering Materials V

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Authors: Seok Keun Koh, Charles Lee, Jung Hwan Lee, Byung Kwuan Kang, Hiroyuki Kaji, Motohiko Hayash, Wan Ho Cho
Abstract: Nano-sized (2~10 nm) metal particles were formed and accumulated on a rotating powders substrate by conventional physical vapor deposition (PVD) process. Sucrose was selected as a supporter for the nano-particles on powder (NPP) process. Nuclei, which were formed on the substrate from vaporized or sputtered metal atoms at an initial thin film growth, did not grow up to coalescence stage and did not agglomerate each other when the powder in the vessel was continuously circulated during the deposition. Size of the nanoparticles is controlled by the physical parameters such as metal evaporation rate, rotation speed of the powder, selection of the powder in the PVD. Formation mechanism of nano-particles on the carrier powder have been explained in terms of thermodynamics with TEM, SEM, EDX, UV spectroscopy, etc. comparing with conventional thin film growth in PVD.
Authors: Natalia Lvova, Ivan Evdokimov, Sergey Perfilov
Abstract: This work provides a comparative study of the mechanical properties of composite materials based on aluminum reinforced with carbon nanostructures. The study involved the tensile strength testing, as well as sclerometry and indentation in the submicron range. We determined the correlation of the values obtained for yield strength and hardness, and the tensile strength and morphology of the residual scratches.
Authors: Sofia Javed, Muhammad Aftab Akram, Mohammad Mujahid
Abstract: Nanoflowers are desirable in light driven applications like Dye Sensitized Solar Cells (DSSCs) due to their large surface area and greater light absorption capabilities. An instant, simple, cheap and environment friendly method of preparing titanium dioxide nanoflowers is presented. The nanoflowers are produced in a time as short as 5 minutes in aqueous conditions without the use of hazardous hydrofluoric acid or organic surfactants at 1 atm. pressure and low temperature of 100°C. Titanium dioxide commercial nanopowders are treated with microwaves in an aqueous sodium hydroxide solution for small durations. The resulting powders are annealed at 450°C in air and characterization is performed using XRD, SEM and Raman spectroscopy.
Authors: Arup Ratan Mandal, Artur Ishteev, Sergey Volchematiev, Denis V. Kuznetsov
Abstract: A strong, simple and rapid method for determination enzyme (papain) conjugated quantum dots (QDs) by dynamic light scattering (DLS) is proposed in this report. Yellow CdSe QDs are synthesized with changing the precursor ratio and confirmed by absorption and emission spectra. Shape and size of synthesized QDs are checked by transmission electron microscope (TEM). Both absorption and emission spectra reveal very strong quantum confinement effect as expected; yellow excitonic emission is observed at room temperature for photoluminescence spectra (PL). The peak maxima are appreciably red-shifted when QDs are conjugated with positively charged papain enzyme. The details possible mechanism is described here, which is very interesting and scarcely addressed before.
Authors: Rey Alfred G. Rañola, Isabella Concina, Elisabetta Comini, Fortunato B. Sevilla, Giorgio Sberveglieri
Abstract: A graphene/polyaniline (rGO/PANi) nanocomposite was synthesized by solution blending method and deposited on to a nylon-6 membrane via vacuum assisted self-assembly (VASA) method to fabricate a flexible material applied as a chemoresistive gas sensor for trimethylamine (TMA). The morphological and structural characterization of surfaced adsorbed polymer nanocomposite was carried out by FT-IR, SEM, UV-Vis and surface profilometry. While, electrical property was carried out by four-point probe measurement. Prepared rGO/PANi nanocomposite has a percolation threshold around 0.40% vol. fraction, with a conductivity of 8.28 S/m (rsd = 3.0%, n=3) and thickness around 38.58 μm (rsd = 7.63%, n=3. The composite sensor exhibited linear range from 45 to 230 mg/L (r2= 0.9962) and the calculated limit of detection was 25.30 mg/L. It exhibited a repeatable response to TMA gas.
Authors: Farah Lyana Shain, Azmizam Manie Mani, Lam Mui Li, Umar Faruk Shuib, Saafie Salleh, Afishah Alias, Khairul Anuar Mohamad
Abstract: This paper investigates the dependence of pressure onto characteristic of Aluminium Zinc Oxide (AZO) thin films. Films were deposited on a glass substrate by RF Magnetron Sputtering using AZO ceramic target with 99.99% purity. Sputtering was performed with RF power of 100 Watt and the deposition times were fixed at 40 minutes. The argon pressures were varied from 10 sccm to 30 sccm in order to achieve different working pressure during deposition in order to study the effect of pressure towards characteristic of films. AZO thin films on different argon pressure were successfully deposited onto glass substrate. All films are polycrystalline with (0 0 2) preferential orientation and fully transparent films with high transparency above 80 percent were achieved. The film deposited at 10 sccm argon flow exhibit the highest growth rate at 7.9 nm/m, highest intensity XRD peak with higher crystalline quality and lowest resistivity that is 2.7 x 10ˉ2 Ω cm .
Authors: Michael Tan, Mary Donnabelle Balela
Abstract: We report a one-pot, low temperature process for the synthesis of high-aspect ratio copper nanowires in aqueous solution for 1 hr. Ethylene diamine (EDA) was utilized to promote anisotropic reduction of Cu (II) by hydrazine. Cu nanowires with mean diameters around 90 nm and lengths exceeding 50 μm were synthesized using 180 mM EDA at 60°C, giving an effective aspect ratio of about 450. Without EDA, nanoparticle growth is observed. The synthesis temperature was also significant in limiting nanoparticle formation. Decreasing the temperature resulted to 1D growth and fewer nanoparticles.
Authors: Catherine P. Garrido, Rinlee Butch M. Cervera
Abstract: Silicon-based anode is one of the most promising anode materials for next generation batteries due to its high theoretical capacity of about 4200 mAh/g. However, the hurdle of using such high capacity anode material is its large volumetric change during lithiation and delithiation causing capacity fading. In this study, in order to circumvent the large volumetric change, nanograined size SiO2 incorporated with Fe having compositions of FexSi1-xO2 (x=0.05, 0.10) have been synthesized using a modified sol-gel processing and fully characterized for its structure, morphology, and thermal properties. From the different characterization results, the samples synthesized at low processing temperatures (400 and 600 °C) suggest an amorphous structure with grain size of about 5 nm and Fe successfully incorporated into the amorphous nanograined SiO2 matrix.
Authors: John Kia Yu Teck, Radhiyatul Hikmah binti Abu, Siti Ujila binti Masuri
Abstract: This paper describes the numerical investigation on the adsorption () of nanoparticles (NPs) scale inhibitor (SI) using Eulerian Computational Fluid Dynamics (CFD) solver ANSYS/FLUENT® based on a scaled down flow model. The simulation were done to investigate theof normal and nanoscaled Calcium-phosphonate. The phosphonate used was 1-hydroxyethylidene-1, 1-disphosphonic acid (HEDP) SI in order to determine the enhancement in adsorption achieved by the nanoscaled SI. This was done by looking at the change in concentration of the SI particles throughout the simulation time. It was found that the two sizes (normal and nanostructured) of the SI particles result in different change in concentration, hence indicates that the two yields different adsorption to the active sites. For the normal SI, the concentration distribution throughout the column remains almost the same as its initial concentration () of 2000 ppm except for very narrow regions in the vicinity of the wall boundaries. This suggests that the rate of process (of the SI onto the wall) is very slow. Consequently, it will take longer time for the SI to be adsorbed to the column wall, hence indicates that it is less efficient. Meanwhile, the nanoscaled Calcium-HEDP SI rapidly shows a significant change in concentration. At 200 s its concentration has distributed evenly in the range of 1960 ppm to 2000 ppm. This shows a really high rate. The results from this study indicates that the nanoscaled Calcium-HEDP SI has better which shows that it is more efficient than normal-scaled Calcium-HEDP SI.

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