Issue 12

Researcher of the Year 2020-To Recognize the Significant Efforts for COVID-19

Ashutosh Tiwari

Advanced Materials Letters, 2020, Volume 11, Issue 12, Pages 1-9
DOI: 10.5185/amlett.2020.121579

In this pandemic year, International Association of Advanced Materials (IAAM) has endeavoured to recognize the best efforts of researchers for their overall efforts to combat COVID-19 in order to select the recipient of the prestigious title of ‘Researcher of the Year’. As an international organization actively working in the scientific community, International Association of Advanced Materials is quite concerned in this time of COVID-19 outbreak. The organization has prioritized all its operations to make valuable contributions to the advanced materials community in this time of need. IAAM believes that the adaptation of advanced technologies and their logical integration according to contemporary healthcare measures could be a smart strategy for COVID-19 management.

Professor Prasad Yarlagadda’s Research Well Adopted as per needs of Engineering Industry

YuanTong Gu

Advanced Materials Letters, 2020, Volume 11, Issue 12, Pages 1-1
DOI: 10.5185/amlett.2020.121580

I know Prof. Prasad Yarlagadda for around 15 years since  I joined Queensland University of Technology (QUT), Brisbane as Lecturer in 2007. I still remembered that Prasad welcomed me to QUT in my first day commencing in QUT. At that time, he was leading Built Environment Engineering (BEE) Faculty as Deputy Director, Centre for Built Environment Engineering Research and also Assistant Dean (Research) in BEE faculty. In addition, he was Director, Smart Systems Research theme and Head, Discipline of Mechanical, Manufacturing and Mechatronics Engineering in QUT. 

The Perspective of a Homogenization Approach for Effective Local and Non-local Response of the Elastic Wave Properties of Phononic Metamaterials

J. Flores-Méndez; R. Pérez Cuapio; C. Bueno Avendaño; Martín Hernández-Ordoñez; M. Aparicio Razo; F. Candia García; I. Vivaldo-De la Cruz; R. C. Ambrosio Lázaro; B. Zenteno-Mateo

Advanced Materials Letters, 2020, Volume 11, Issue 12, Pages 1-7
DOI: 10.5185/amlett.2020.121581

This review summarizes progress about a recent homogenization theory based on the Fourier formalism for solid phononic crystals, which is valid for arbitrary Bravais lattice and any form of inclusions in the unit cell. The theory provides explicit expressions for the tensors of the effective nonlocal elastic response (dependence on frequency and wave vector), namely the effective dynamic mass-density and compliance matrices. With the use of this theory, our predictions in the quasistatic limit for one and two-dimensional phononic crystals coincide with those of finite-element and asymptotic-homogenization methods. It is also shown that the derived expressions can be applied to phononic crystals with liquid components (two-dimensional sonic crystals) and agree with predictions of the multiple scattering theory. The formalism of non-local effects is fully demonstrated only for a one-dimensional elastic metamaterial having simultaneously negative effective dynamic mass density and elastic shear modulus. The development and applications of this homogenization theory, unlike other formalisms, arises from the inspiration of intense research efforts to simultaneously describe local and non-local effective properties in elastic periodic structures.

Reactor Cycling of Granulated Ca(OH)2 Encapsulated with Chemically Modified Semipermeable Shell Materials

Klaus Afflerbach; Sandra Afflerbach; Reinhard Trettin; Wolfgang Krumm

Advanced Materials Letters, 2020, Volume 11, Issue 12, Pages 1-10
DOI: 10.5185/amlett.2020.121582

One major scientific challenge is a shift of the energy generation and utilization towards sustainability and efficiency. Therefore, thermochemical heat storage concepts offer a promising contribution as for example by integration in Concentrated Solar Power (CSP) applications. The reaction system Ca(OH)2/CaO is seen as a superior candidate but its poor powder properties yet hinder a technical implementation. The authors have recently proven, that these obstacles can be overcome by a persistent particle size stabilization of the pre-granulated storage material. Within the present study, the mechanical capsule material properties are improved by admixing of additives to the powdery precursor. By thermochemical conversion in a laboratory reactor, the cyclability and the suitability for moved reaction beds of the storage material is proven. The investigations are complemented by attrition tests on the most promising sample material and an encapsulated reference material. It is shown that the chemically enhanced encapsulation is a suitable approach to retain good flow properties and reduce attrition significantly. An encapsulated sample with an enhanced shell material composition containing 5%(w/w) of diatomaceous earth and 1%(w/w) of flux agent is found to be of superior stability over ten thermochemical cycles. A comparative macroscopic evaluation of the sample material after tenfold thermochemical cycling emphasizes the potential of this approach.

Nanotoxicological Assessments to Warranty the use of Functionalized Y2O3 Nanoparticles for Biomedical Applications

D. Chávez-García; K. Juarez-Moreno; R. Reyes; J. Barrera; G. A. Hirata

Advanced Materials Letters, 2020, Volume 11, Issue 12, Pages 1-9
DOI: 10.5185/amlett.2020.121583

This study is a summary of our results on synthesis, functionalization and biomedical application of luminescent lanthanide doped nanoparticles with Y2O3 as host lattice. The nanoparticles (NPs) studied were Y2O3 and Y2O3: Eu 3+ and they are water-monodispersed, synthesized by the sol-gel method and surface modified to be biocompatible with a silica shell. The NPs were conjugated with amine groups and folic acid to detect specific cancer cells. We carried out a complete nanotoxicological evaluation of NPs in HeLa and MCF-7 cancer cells and fibroblast (L929) cell line. Our results corroborate the bio- and hemo-compatibility of NPs. No in vitro inflammatory response mediated by macrophages was elicited and no genotoxic effect was scored by comet assay. Internalization of folic acid-functionalized NPs was detected by flow cytometry comparing the internal cellular complexity and the cytoplasmic localization of NPs was confirmed by confocal microscopy. We provide with more evidences to warranty the biosafety of down conversion nanoparticles based on Y2O3: Eu 3+ and functionalized with folic acid for further biomedical and bio-imaging applications.

Comparison of Photocatalytic Efficiency of TiO2 and In2S3 Thin Films under UV and Visible Light Irradiance

Alphonsa Paul; Jilu C. John; Saji Augustine; Tina Sebastian; Ardhra Joy; Juliya Joy; Tintu Maria Michael; Akhila K.S.

Advanced Materials Letters, 2020, Volume 11, Issue 12, Pages 1-7
DOI: 10.5185/amlett.2020.121584

We use simple, cost effective deposition techniques of doctor blading and chemical bath deposition to synthesize uniformly dispersed nanoparticle thin films of Titanium dioxide (TiO2) and mesh fractal thin films Indium sulphide (In2S3) respectively. The resulting microstructures and phase composition of these films are characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and the optical studies are carried out using UV-Visible-NIR spectroscopy. Further, we report these thin films are photocatalytically active in different spectral regions and a comparative study is detailed in this work. The photocatalytic studies of both the films are carried out by using methylene blue (MB) dye as pollutant and their efficiencies are compared under UV and visible light irradiation. The results obtained shows that the photocatalytic efficiency of TiO2 film was conspicuous in the UV region where as In2S3 films showed significant activity in the visible region. Present study also confirms that photocatalysts in thin film forms are ideal for practical applications as they are efficient and also can be retrieved easily from the solution. These features favour their extensive use in eco-friendly environmental applications such as degradation of environmental pollutants, waste water treatment in textile industries and water purification.

Application of Rice Husk Ash as Thermal Insulation Materials

Chee Wah Loy; Khamirul Amin Matori; M.M. Haslinawati; Mohd Hafiz Mohd Zaid; Norhazlin Zainnudin

Advanced Materials Letters, 2020, Volume 11, Issue 12, Pages 1-5
DOI: 10.5185/amlett.2020.121585

A low thermal diffusivity SiO2-based ceramic was fabricated by sintering Malaysia agricultural waste rice husk at 800 °C. This paper presents the effect of sintering temperatures on the phase transformation, microstructure and thermal diffusivity of rice husk ash (RHA) as a thermal insulating material. A series of SiO2-based ceramics were fabricated from rice husk via two sintering stages. Rice husk was pre-sintered at 700 °C and then ground into powder. The RHA powder was compacted into pellets and then re-sintered at a single temperature between 700 and 1400 °C. Sintering of the RHA induces phase transformation from amorphous silica to crystalline α-cristobalite, α-tridymite and β-tridymite. The thermal diffusivities of RHA were evaluated using the laser flash analysis technique. The results indicate RHA-800 °C has the lowest thermal diffusivity, which is 0.17 ± 0.1 mm 2 s −1 at 25 °C. The RHA particle morphologies were observed using a field-emission scanning electron microscopy. Low-frequency vibrational modes of silica such as lattice vibration were investigated using Fourier-transform infrared spectroscopy technique. X-ray fluorescence result indicated that RHA-800 °C contains ~90 wt % of SiO2.

Synthesis and Characterization of Green CuO using Centella Asiatica Plant Leaf Extract: Electrochemical and Photocatalytic Activities

K. Rudresha; A. Zahir Hussain; Ravikumar C. R.; M. R. Anil Kumar; Nagaswarupa H. P.; M. S. Santosh; H. C. Ananda Murthy

Advanced Materials Letters, 2020, Volume 11, Issue 12, Pages 1-6
DOI: 10.5185/amlett.2020.121586

The green CuO NPs were successfully synthesised by green solution combustion method. The average crystallite size of green solution combustion CuO nanoparticles (gsc-CONPs) was found to be 40.64 nm and confirmed by powder X-ray diffraction (PXRD) analysis. The UV-DRS spectrum revealed average energy gap of 1.75 eV for gsc-CONPs. Cyclic voltammetry (CV) and Electrochemical impedance spectroscopy (EIS) techniques have been employed to analyse the electrochemical properties of the synthesized sample by using carbon paste electrodes in 1M KOH solution. The observed results suggest superior electrochemical properties of gsc-CONPs electrode due to its lower value of EO-ER. It also exhibited better sensor characteristics for paracetamol and glucose molecules. The proton diffusion coefficient (D) for the gsc-CONPs electrode material was found to be 1.134 × 10-4 cm 2 s -1 . The g-CONPs have also been tested for its photocatalytic activity using indigo carmine (IC) dye. The mechanism suggests that the crucial role was played by OH radicals during dye degradation. The results support the claim of the synthesized gsc-CONPs as a promising material for photocatalytic and supercapacitor applications.

Dielectric Relaxation and Suitability of Scaling parameters study on Mn0.7+xZn0.3SixFe2-2xO4 (x = 0.0 - 0.3) Ferrites

Nimish H. Vasoya; Kiran G. Saija; Akshay R. Makadiya; Tushar K. Pathak; Urmila M. Meshiya; Pooja Y. Raval; Kunal B. Modi

Advanced Materials Letters, 2020, Volume 11, Issue 12, Pages 1-8
DOI: 10.5185/amlett.2020.121587

The compositional dependence of the real (ε') and imaginary (ε'') parts of complex dielectric permittivity (ε*) and loss tangent (tan d) for Mn0.7+xZn0.3SixFe2-2xO4 (x = 0.0, 0.1, 0.2 and 0.3) spinel ferrite series was investigated over wide frequency (f = 20 Hz to 1 MHz) and temperature (T = 300 K to 673 K) ranges. Frequency dependence of ε',ε'' and tan δ has been explained based on the two-layer model of dielectrics. The nonlinear relationship between ε'(f) and σ'(f) suggests multi-relaxation process and formation of a broad hump in ε'(f, T) plots indicates collective contributions from electrons and holes to the polarization. The scaling by normalized frequency (f/fc) and scaled frequency (f/σdc) are found successful for ε' in high-frequency regime only while scaling found successful for ε'' over the whole range of frequency. The suitability of various scaling parameters was also tested for the master curve generation. The co-existence of localized and delocalized relaxations is verified.

Synthesis and Screen Printing of Dopant Free Nano-crystalline SnO2 (101) Thick Film for Gas Sensor Application

Anil D. Garje; Manoj Mayaji Ovhal; Shweta Mishra; Namrata Bagwe

Advanced Materials Letters, 2020, Volume 11, Issue 12, Pages 1-7
DOI: 10.5185/amlett.2020.121588

Nano-crystalline tin (II) oxide (SnO2) was successfully synthesized by a simple and cost-effective surfactant assisted solution precipitation technique. The structural, optical, and morphological characterization of as synthesized nano-crystalline SnO2 was confirmed by X-Ray diffraction (XRD), ultraviolet-visible (UV-Vis) spectroscopy, and transmission electron microscopy (TEM). The nano-crystalline SnO2 possesses tetragonal lattice structure (rutile phase) with preferential growth along (101) plane and average crystallite size of 8 ±2 nm were confirmed by XRD Rietveld refinement. The TEM images were showed quasi spherical particles with average particle size of 10 ±2 nm. The optical energy band gap of 3.76 eV confirms the electronic conduction mechanism in SnO2. Furthermore, the synthesized nano-crystalline SnO2 with 15 wt % glass frit was used as a functional material to fabricate thick film sensors using cost-effective screen printing method.  The sensor shows high sensitivity towards H2, CO, and LPG selectively at optimal operating temperatures of 120, 150 and 70 o C respectively for 100 ppm concentration of each gas. The improvement in sensitivity, selectivity, and stability at low operating temperature and their correlation with the nano-crystalline SnO2 (101) plane, small particle size and optical band gap were also envisaged along with repeatability, reproducibility, calibration, and aging effect.