Volume 12, Issue 6, June 2021

Advanced Materials Research and Innovation Priorities for Accomplishing the Sustainable Development Goals

Ashutosh Tiwari

Advanced Materials Letters, 2021, Volume 12, Issue 6, Pages 1-6
DOI: 10.5185/amlett.2021.061633

Advanced Materials community has committed to work in line with the United Nations’ Sustainable Development Goals (SDGs) for a green future. The International Association of Advanced Materials (IAAM) is stepped into the next decade by leading the ‘Advancement of Materials to Sustainable and Green World’. The people understand that having a sustainable future should be the most important aim of humankind’s priorities. With its accumulative sustainable development agenda, the association puts world-wide efforts with Materials Science, Engineering, and Technology across spheres of academia and industry towards potentially addressing the challenges of sustainability of materials research and innovation for a green world.

Contemporary Advances in Humidity Sensing Materials, Methods, and Performances

N.S. Abbas; S.K. Shukla

Advanced Materials Letters, 2021, Volume 12, Issue 6, Pages 1-13
DOI: 10.5185/amlett.2021.061634

The present review paper describes the advances in materials, mechanisms, and techniques for humidity sensing along with their applications in terms of parameters, utility, durability, and spectrum. Advances in different types of humidity sensing materials are described along with their processing techniques, significance in humidity sensing properties, and applications. The newer application for the use of humidity sensors i.e. monitoring of respiration, metabolic rate, quality of organic solvents, packaging, power plants, agriculture practices, and forensic cases was also explained with suitable illustrations and current references.  Although humidity sensing is a very old analytical tool but still suffers from several challenges for appropriate applications. In conclusion, a road map for the nexus between materials science, technology, applications, and existing challenges are presented about humidity sensors.

Roles of the Debye Length and Skin Depth in the Characterization of Space Charge Interactions in Semiconductor Nanoparticles

Zhijing Hu; Zi Wang; Yanlin Li; Tao Shen; Ming Yan; Thomas Wong

Advanced Materials Letters, 2021, Volume 12, Issue 6, Pages 1-8
DOI: 10.5185/amlett.2021.061635

Non-degenerate semiconductor nanoparticles with bulk plasma frequency in the terahertz frequency range are of substantial current interest for device and sensing applications in that part of the electromagnetic spectrum. The penetration of electromagnetic field in a material containing mobile charges is governed by two length scales, namely the Debye length and the skin depth. Their relative influence on the response of a semiconductor nanoparticle to an external terahertz electric field is examined in this Letter. A transport-based formulation to describe charge-field interactions by coupling the Boltzmann equation with the field equations is employed to characterize space-charge effects.  Numerical results computed with the charge transport formulation reveal that plasmonic interactions in a semiconductor nanoparticle remains a surface phenomenon up to the surface plasmon resonance frequency, beyond which it evolves into a bulk phenomenon as the inertia effect of the charge carriers subdues their response to the field, which penetrates deeper into the particle as the frequency is increased. Examination of the spectra of charge, field, and current distributions allows for the identification of the influence of particle size, Debye length and skin depth on space charge interactions in a semiconductor nanoparticle.

Antifungal Activity of Iron-gold and Cobalt-gold co-doped ZnO Nanoparticles

A. Ferin Fathima; R. Jothi Mani; K. Sakthipandi

Advanced Materials Letters, 2021, Volume 12, Issue 6, Pages 1-5
DOI: 10.5185/amlett.2021.061636

Zn0.98Fe0.01Au0.01O and Zn0.98Co0.01Au0.01O nanoparticles (NPs) have been synthesized via poly ethylene glycol assisted route. The average crystallite size of Zn0.98Fe0.01Au0.01O and Zn0.98Co0.01Au0.01O NPs were estimated from X-ray diffraction results and the values are 31.38 nm and 36.14 nm respectively. The UV absorption spectra confirmed the formation of the NPs with the characteristic peaks at 374 and 366 nm respectively. This spectral observation indicates that the band gap of ZnO nanoparticles decreases by doping iron/gold and cobalt/gold nanoparticles. The morphology and elemental composition of Zn0.98Fe0.01Au0.01O and Zn0.98Co0.01Au0.01O NPs were investigated. The antifungal activity of synthesized Zn0.98Fe0.01Au0.01O and Zn0.98Co0.01Au0.01O NPs were found against four postharvest pathogenic fungi like Aspergillus niger, Aspergillus flavus, Rhizopus microsporus and Pencillium sp < /em>. The doping of iron and gold in ZnO nanoparticles enhances the zone of inhibition for the fungal pathogens compared to pure ZnO nanoparticles. Antifungal activity of Zn0.98Fe0.01Au0.01O and Zn0.98Co0.01Au0.01O nanoparticles were higher when compared with standard antibiotic mycostatin whose zone of inhibition is 18 mm against Aspergillus niger, Aspergillus flavus, Rhizopus microsporus and Pencillium sp.

Adsorption and Thermodynamic Parameters of Activated Carbon-Diazepam Systems in Simulated Gastric Fluid

Carlos A. Ray-Mafull; Dachamir Hotza; Raquel García-Gallardo; Orlando F. Cruz Junior; Jarosław Serafin

Advanced Materials Letters, 2021, Volume 12, Issue 6, Pages -
DOI: 10.5185/amlett.2021.061637

In this study, the adsorption and thermodynamic parameters of Diazepam drugs adsorbed onto six activated carbons were determined. A simulated gastric fluid was applied at pH 1.2 for 4 h. The samples were characterized by FTIR, N2 isotherm at 77 K, and CO2 at 273 K. The experimental adsorption was fitted by isotherm models: Langmuir Type I and II, DR, Halsey, Freundlich, Harkins-Jura, Temkin, and BET. UV visible spectra monitored residual drugs. The results showed relationships between temperature increase, adsorbent characteristics, and the behavior of these drugs in acid solution. The positive values of all the isosteric adsorption enthalpies determined from the slope Van’t Hoff plot (R 2 >97) indicated the endothermic nature of the adsorption process. In all cases, ΔG<0 so that the spontaneous character of the adsorption process was attested. Moreover, the positive values of ΔS stated that the randomness increased at the solid-solution interface during the adsorption process.

Synthesis, Impedance and Current-Voltage Spectroscopic Characterization of Novel Gadolinium Titanate Nano Structures

Vinayak M Adimule; Debdas Bhowmik; Adarsha Haramballi Jagadeesha

Advanced Materials Letters, 2021, Volume 12, Issue 6, Pages 1-7
DOI: 10.5185/amlett.2021.061638

Gadolinium (Gd) doped titanate nanostructures (NS) with a new set of 10-50 wt. % of Gd were synthesized by microwave-assisted hydrothermal and reduction using hydrazine hydrate. The crystal structure has been evaluated with SEM (scanning electron microscopy) analysis exhibited rod like geometry of nanoparticles (NPs). XRD (X-ray diffraction spectroscopy) analysis of GdTiO3 and undoped titanate nanostructure (NS) intense peak exhibited crystal tetragonal structure. CV (cyclic voltammetry) exhibited an oxidation potential of 50 wt. % of GdTiO3 was found to be - 0.54 eV. UV-Visible spectroscopic revealed absorptivity of 50 wt. % of GdTiO3 was found to be 650 nm (visible region) and undoped titanate absorptivity at 320 nm (UV region). The pelletized nanostructures of GdTiO3 were investigated for current-voltage (I-V), capacitance-voltage (C-V), resistance-voltage (R-V) measurements, which showed frequency range in between 1 kHz to 2 MHz and 50 wt. % GdTiO3 NS showed a decreasing trend in admittance value with an increase in frequency. However, an increase in the conductance, power dissipation values with a decrease in resistivity, and increase in the frequency has been noticed which embark considerable variation in conductivity and power dissipation in GdTiO3 NS. The results from the plots of current-voltage (I-V), capacitance-voltage (C-V), and bias voltage with an applied frequency of the GdTiO3 NS has been discussed.

Removal of Toxic Dyes from Industrial Waste Water using Chitosan Grafted Itaconic Acid Nanocomposites

M. Swathi; Pratik Roy; M. V. Deepthi; R. R. N. Sailaja

Advanced Materials Letters, 2021, Volume 12, Issue 6, Pages 1-10
DOI: 10.5185/amlett.2021.061639

In this study chitosan (CTS) has been grafted with itaconic acid (IA) by following microwave assisted grafting method. Three different types of nanomaterials namely nanoclay, cloisite 30B and multiwalled carbon nanotubes (MWCNT) have also been incorporated during the grafting reaction. The synthesized nanocomposites were used for the removal of napthol green, reactive black and congo red dyes from aqueous solutions. Results showed enhanced dye adsorption capacity after addition of nanomaterials. The adsorption isotherm fitted well with Langmuir model. It was observed that CTS grafted IA composite with cloisite 30B exhibited highest napthol green adsorption rate compared to others. CTS grafted IA composite with MWCNT showed better congo red and reactive black adsorption rate as compared to CTS nanocomposite modified with nanoclay and cloisite 30B. The swelling kinetics in acidic, basic and neutral medium was found to follow pseudo second order kinetic model. Fourier transform infrared spectroscopy (FTIR) analysis showed successful grafting of IA on CTS. X-ray diffraction (XRD) and morphological characteristics suggested enhanced dispersion of nanomaterials in CTS matrix.

Structural, Optical and dielectric properties of Sr doped LaVO4

Khalid Sultan; Rubiya Samad; Feroz A. Najar; Shohaib Abass; Saima Jahan; Mudasir Rashid Rather; M. Ikram

Advanced Materials Letters, 2021, Volume 12, Issue 6, Pages 1-6
DOI: 10.5185/amlett.2021.061640

Polycrystalline bulk samples of chemical composition La1-xSrxVO4 (x = 0.0, 0.1, 0.3, 0.5) were prepared by solid state reaction method. The Morphology and structure wascharacterised by Scanning Electronic microscopy and powder X-ray diffraction respectively. All the prepared material were single-phase and co-doped ions were successfully incorporated in LaVO4 lattice. The EDAX spectrum shows that the percentage composition of given elements in the proposed formula was in good agreement with the corresponding values determined experimentally. The Raman spectra of LaVO4 reflect the VO4 type structure that consists of four different V–O bands. The prominent Raman band at about 860 cm -1 can be assigned to the symmetric V–O stretching mode while the weak Raman band at 792 cm -1 is assigned to antisymmetric V–O stretching mode. With increase in Sr doping, optical band gap was found to decrease resulting in increase in conductivity. The dielectric constant as well as dielectric loss shows a relaxor type of behaviour for higher doping concentration which can be attributed to the chemical pressure induced in LaVO4 with the doping of Sr ions. The studies performed on ac conductivity identifies that the conduction mechanism follows the charge hopping between localised states and follow the small polaron conduction.

Design, 3D Development and Finite Element Analysis of Cylindrical Mesh Cage Bioimplants from Biometals

Harbhajan Ahirwar; Himansu Sekhar Nanda

Advanced Materials Letters, 2021, Volume 12, Issue 6, Pages 1-5
DOI: 10.5185/amlett.2021.061641

The current research is aimed at design and 3D development of a degradable cylindrical mesh cage porous bioimplant for fixation to a segmental femur bone defect. The finite element analysis (FEA) was carried out to obtain the bone-bioimplant interface deformation and stress generated. The cylindrical mesh cage bioimplant was designed using a range of metallic biomaterials such as Magnesium (Mg) alloy (AZ31), Ti alloy (Ti-6Al-4V) and Stainless Steel (SS316L). The FEA was carried out for bone-bioimplant assembly in static and dynamic conditions. FEA results demonstrated that the values of the interface von-mises stress for the AZ31 Mg-alloy based bioimplant  could fall with in the clinical acceptable domain at which the stress sheilding issues could be avoided. The results further suggested that Mg-based bioimplants could be promising and better alternative for use as a porous scaffold for repair and regeneration of a segmental femur bone defect.