Optical properties of nanostructured ruthenium dioxide thin films via sol–gel approach

High purity ruthenium dioxide (RuO₂) nanoparticles with the average size is about 9 nm in diameter are readily synthesized through a low cost sol–gel method. RuO₂ thin films have been deposited on SiO₂ substrates by sol–gel spin coating techniques at room temperature, followed by annealing at 500 °C for 2 h. The result of X-ray diffraction indicates that the RuO₂ nanoparticles are well crystallized with a rutile tetragonal structure. Morphological of RuO₂ films were characterized using atomic force microscopy (AFM), transmission electron microscopy and high resolution transmission electron microscopy. The AFM images confirmed a spherical-shape nanoparticles with diameter of 9 nm and surface roughness of 12 nm of the films. The optical absorption studies showed the presence of direct band transition with band gap equal to 1.87 eV. Refractive index and dielectric properties of the films were estimated from optical measurements. Room temperature photoluminescence of RuO₂ film showed an emission band at 432 nm.     

Targeting of Glycosaminoglycans in Genetic and Inflammatory Airway Disease

In the lung, glycosaminoglycans (GAGs) are dispersed in the extracellular matrix (ECM) occupying the interstitial space between the capillary endothelium and the alveolar epithelium, in the sub-epithelial tissue and in airway secretions. In addition to playing key structural roles, GAGs contribute to a number of physiologic processes ranging from cell differentiation, cell adhesion and wound healing. Cytokine and chemokine–GAG interactions are also involved in presentation of inflammatory molecules to respective receptors leading to immune cell migration and airway infiltration. More recently, pathophysiological roles of GAGs have been described. This review aims to discuss the biological roles and molecular interactions of GAGs, and their impact in the pathology of chronic airway diseases, such as cystic fibrosis and chronic obstructive pulmonary disease. Moreover, the role of GAGs in respiratory disease has been heightened by the current COVID-19 pandemic. This review underlines the essential need for continued research aimed at exploring the contribution of GAGs in the development of inflammation, to provide a better understanding of their biological impact, as well as leads in the development of new therapeutic agents.     

Exp-function method for solving nonlinear evolution equations with higher order nonlinearity

In this paper, the Exp-function method is used to obtain generalized solitary solutions of the generalized Drinfel’d–Sokolov–Wilson (DSW) system and the generalized (2+1)-dimensional Burgers-type equation. Then, some of the solitary solutions are converted to periodic solutions or hyperbolic function solutions by a simple transformation. The results show that the Exp-function method is a powerful and convenient mathematical tool for solving nonlinear evolution equations with higher order nonlinearity.     

Thermo-bioconvection effect on hybrid nanofluid flow over a stretching/shrinking melting wedge

The research focused on nanomaterial solutions and their flow characteristics in relation to their usage. The application of such composites in biological rheological models, in particular, has received a lot of interest. The use of nanofluids in cooling tiny electronic devices like microchips and associated devices cannot be emphasized. Our goal is to explore the influence of a binary chemical reaction and Arrhenius activation energy on a hybrid nanofluid over a melting wedge in a spongy media. It is anticipated that the water-based nanoparticle contains gyrotactic microbes. By using appropriate similarity variables, the resultant dimensional nonlinear boundary-layer model is reduced and turned into a dimensionless form. A Chebyshev spectral collocation approach is useful in solving the highly nonlinear model. In terms of physical importance, the effects of important factors on developing profiles are displayed graphically and explained. Computational outcomes are obtained via MATHEMATICA. The plot of residual error is also shown to demonstrate the method's rapid convergence. According to the study's findings, by increasing the melting parameter, the rate of heat transportation at the wall decreases greatly on the average of 12.81%, but the Sherwood number becomes effective for the chemical reaction rate with a rate of about 24.81%.     

Microstructural and Tribological Behavior of Pack-Borided Ni-Based Hastelloy C-276 Superalloy

Metallurgical and Materials Transactions A - Although the toughness and corrosion resistance of Ni-based superalloys are high due to their face-centered-cubic structure, their surface hardness and,...     

Economic and environmental impact of electric vehicles production in Indonesia

The use of fossil fuel-based vehicles may gradually be replaced by electric vehicles in the future. The trend indicates that the number of users of electric vehicles, especially electric cars, continues to increase. Indonesia is well-positioned to take advantage of this opportunity as it has the world’s largest nickel reserves, an essential raw material for making electric vehicle batteries (EVB). The study examines the economic and environmental implications if Indonesia were to successfully set up electric vehicle (EV) production rather than exporting such raw materials overseas. We use an input–output model to estimate electric vehicle production’s economic and environmental impacts in Indonesia. This study assumes that nickel, which is usually exported, is absorbed by domestic economic activities, including being used in manufacturing batteries and electric vehicles in Indonesia. Our estimates include direct and indirect output, value-added, and employment changes. The same model is also used to estimate changes in emissions’ environmental costs. It is evident from the results that batteries and EV production are economically beneficial. Additional value-added is Rp. 100.57 trillion, 1.5% of GDP in 2010. At the same time, 538,658 additional jobs were created, which is about a 0.5% increase. Lastly, EV production will have extra external costs of emissions, around Rp. 2.23 trillion, or an increase of about 0.6%. Based on these findings, it is concluded that electric vehicle production increases productivity, gross value-added, and job creation with a relatively small impact on the environment. A limitation of this study is that we assumed EVs were produced for export only, and we did not assume a reduction in economic activities in the supply chain of conventional vehicles.

Graphical Abstract

Economic and Environmental Impact of Electric Vehicles Production in Indonesia.

     

Flexible Nanoarchitectonics for Biosensing and Physiological Monitoring Applications

Flexible and implantable electronics hold tremendous promises for advanced healthcare applications, especially for physiological neural recording and modulations. Key requirements in neural interfaces include miniature dimensions for spatial physiological mapping and low impedance for recognizing small biopotential signals. Herein, a bottom-up mesoporous formation technique and a top-down microlithography process are integrated to create flexible and low-impedance mesoporous gold (Au) electrodes for biosensing and bioimplant applications. The mesoporous architectures developed on a thin and soft polymeric substrate provide excellent mechanical flexibility and stable electrical characteristics capable of sustaining multiple bending cycles. The large surface areas formed within the mesoporous network allow for high current density transfer in standard electrolytes, highly suitable for biological sensing applications as demonstrated in glucose sensors with an excellent detection limit of 1.95 µm and high sensitivity of 6.1 mA cm⁻² µM⁻¹, which is approximately six times higher than that of benchmarking flat/non-porous films. The low impedance of less than 1 kΩ at 1 kHz in the as-synthesized mesoporous electrodes, along with their mechanical flexibility and durability, offer peripheral nerve recording functionalities that are successfully demonstrated in vivo. These features highlight the new possibilities of our novel flexible nanoarchitectonics for neuronal recording and modulation applications.     

Time-dependent pressure-driven flow in a horizontal cylinder filled with a bidisperse porous material

Some properties of time-dependent that modify Brinkman equations for fluid flow in a cylindrical tube filled with Bidisperse Porous Material are discussed in this article. The fluid velocities through the fracture and porous phases of the Bidisperse Porous Medium (BDPM) resulting from the application of pressure gradient are described by two coupled second-order partial differential equations. Laplace transform technique, D'Alembert and Riemann-Sum Approximation Methods are used to obtain a semianalytical solution for the model. The choice of the D'Alembert is made to systematically decouple the coupled governing equations without altering their initial orders. The role of the coupling parameter: The coefficient of momentum transfer $(\eta )$ in the flow formation is considered. Accordingly, three cases are analyzed: (a) weak coupling $(\eta =0)$ which described the fluid flow in the absence of the coupling parameter, (b) the strong coupling resulting from a large value of the coupling parameter $(\eta \to \infty )$, and (c) fluid momentum for any arbitrary value of $\eta$. It is observed that fluid stability is attained when ${\mathit{Da}}_f$ and ${\mathit{Da}}_p$ are decreased; a finding that agrees with the findings of Nield and Kuznetsov and Magyari. Also, the maximum velocity in the fracture phase of the BDPM is attained when the coefficient of momentum transfer is neglected $(\eta =0)$ while an opposing flow formation is demonstrated in the fracture and porous phases of BDPM as $\eta$ is increased.     

Run-up flow of MHD fluid between parallel porous plates in the presence of transverse magnetic field

This paper investigated the run-up flow of magnetohydrodynamics (MHD) incompressible, viscous, Newtonian fluid bounded by two parallel horizontal porous plates in the presence of transverse magnetic field. The fluid flow is initially due to constant pressure gradient, placed parallel to the plates. On attaining steady state, the pressure gradient is suddenly withdrawn and the lower porous plate is set into motion in its own plane, this phenomenon is termed as run-up flow. The transfer of momentum is as a result of the disturbances emanating from the boundary into the fluid. The initial value problem is solved using Laplace transform technique to obtain the closed-form solution for the velocity in the Laplace domain. Semi-analytical result is obtained by an inversion technique based on Riemann-sum approximation to invert the solution for velocity into its corresponding time domain. The mathematical simulation conducted shows that increasing the Hartmann number is observed to decrease the fluid velocity while increasing the pressure gradient is found to enhance the fluid velocity. Furthermore, the opposing effects of suction/injection parameter on the fluid velocity have been established in the research.