Review Article
Metamaterials
Changfang Zhao
Abstract
Metamaterials are a class of periodic or aperiodic artificial microstructures with unusual physical properties. Their unique and controllable properties provide rich design inspiration for human technology products. Negative Poisson’s ratio (NPR) metamaterial, also known as auxetic metamaterial, ...
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Metamaterials are a class of periodic or aperiodic artificial microstructures with unusual physical properties. Their unique and controllable properties provide rich design inspiration for human technology products. Negative Poisson’s ratio (NPR) metamaterial, also known as auxetic metamaterial, is a kind of mechanical metamaterial that can produce NPR effect different from common materials in nature, and has a long history of development and a wide range of application scenarios. This paper mainly reports the basic characteristics, development process and research content of auxetic metamaterial, and makes corresponding analysis and prospect, aiming to popularize its concept and explore its development potential in the field of mechanics. However, it should be noted that with the development of new technologies such as additive manufacturing and artificial intelligence, the future of auxetic metamaterial is still full of uncertainties. To this end, the design of new configurations, the coupling of new functions and the implementation of new applications may become concerns, which will make auxetic metamaterials more interesting.
Research Article
Carbon Materials and Technology
Bidit Lamsal; Deepshikha Karki; Ramesh Puri; Kamal Prasad Sharma; Takahiro Maruyama; Rameshwar Adhikari
Abstract
Charcoal was prepared in a facile way using a muffle furnace by direct pyrolysis of mustard oil cake and sugarcane bagasse attempting inert gas-free high-temperature pyrolysis at 900 °C. The structure of the obtained product was analyzed by Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), ...
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Charcoal was prepared in a facile way using a muffle furnace by direct pyrolysis of mustard oil cake and sugarcane bagasse attempting inert gas-free high-temperature pyrolysis at 900 °C. The structure of the obtained product was analyzed by Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. The lack of long-range order in the prepared charcoal has been attested by the appearance of weak and broad 2D peaks in the Raman spectra. The diameter of the crystallites was found to be 3.66 nm (mustard oil cake) and 3.79 nm (sugarcane bagasse). The material was found to consist essentially of amorphous carbon with the presence of oxygen-containing functional groups. On analyzing the elemental composition by XPS, only carbon and oxygen atoms were observed. The charcoal was found to retain the layered morphology, organized in a sheet-like or flakes-like manner, of precursor lignocellulosic biomass. Charcoal with properties comparable to that obtained from the conventional method could be prepared in the absence of inert gas.
Research Article
Nanomaterials & Nanotechnology
Pui-Lam Ng; Jiajian Chen; Albert K.H. Kwan
Abstract
Nano silica sol is an aqueous solution containing colloidal nano-silica. From limited research in the literature, it has been reported to offer better effects on the cement-based materials compared with nano-silica powder, which is by far the most widely studied nano-material. In this research, the possible ...
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Nano silica sol is an aqueous solution containing colloidal nano-silica. From limited research in the literature, it has been reported to offer better effects on the cement-based materials compared with nano-silica powder, which is by far the most widely studied nano-material. In this research, the possible use of nano silica sol to improve the performance of marine cement-based mortar is investigated. The optimal type of nano silica sol among acidic, neutral, and alkaline pH is identified, followed by systematic experimentation of the flexural strength, compressive strength, chloride ion permeability, as well as Fourier-transform infrared (FTIR) spectrum and X-ray diffusion (XRD) pattern. It was found that alkaline nano silica sol outperformed acidic and neutral counterparts. Generally, the addition of nano silica sol increased the flexural and compressive strengths of marine mortar. Addition of 3% nano silica sol by volume of cement yielded remarkable effects, while further addition of nano silica sol yielded diminishing returns. The FTIR spectra and XRD patterns suggested the nano silica sol induced nucleation effect at relatively early age and pozzolanic reaction effect at relatively late age. These effects improved the performance of marine cement-based mortar.
Research Article
Functional Materials
Visileanu Emilia; Alexandra Gabriela Ene; Carmen Mihai; Razvan Scarlat; Catalin Grosu; Andreea Ghita
Abstract
Physical vapour deposition (EB-PVD) is a well-known technology that is widely used for the deposition of thin films regarding many demands, with a wide range of applications such as conductive textiles. It is a technique in which a high-energy electron beam is used and the metal is deposited on the surface ...
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Physical vapour deposition (EB-PVD) is a well-known technology that is widely used for the deposition of thin films regarding many demands, with a wide range of applications such as conductive textiles. It is a technique in which a high-energy electron beam is used and the metal is deposited on the surface of the substrate in the molecular form under high vacuum conditions. EB-PVD techniques have many advantages, including the high purity, efficiency and ecological nature of the process; the possibility of using substrates mainly in the form of gases and pure metals instead of expensive, complex and usually toxic chemical compounds; the possibility of producing both non-stoichiometric with different properties.In our research, the development of a primary haemostasis device designed to save the lives of combatants is based on a conductive textile substrate that was achieved by thin film deposition of Cu particles with a hybrid PVD (Physical Vapor Deposition) system, type Torr-Model No: 5X300EB-45KW. A commercial Cu target (99.999%) with a diameter of 2 inches and a thickness of 3 mm was used for deposition. The technological flow of EB-PVD deposition and working parameters for achieving Cu coating were established. The thickness of the deposited layer on textiles was 5µm. The values of electrical conductivity (S/m) obtained on 1 inch of textile surface, were 34.426,67 S/m (V1) and 6.179,15 S/m (V2) and on a 10-inch textile surface, 84.005,38 S/m (V1) and 7.961,02 S/m (V2). SEM analysis of the coated surfaces and semi-quantitative EDS chemical point analysis were performed.
Research Article
Nanomaterials & Nanotechnology
Ryan M Lumod; Khia Jane D Avila; Rolen Brian P Rivera; Miceh Rose A Magdadaro; Noel Lito B Sayson; Felmer S Latayada; Gerard G Dumancas; Rey Y Capangpangan; Arnold C Alguno
Abstract
Gold nanoparticles (AuNPs) have wide-ranging applications across scientific disciplines and industries. However, its conventional synthesis methods pose environmental and health risks, prompting the rise of green chemistry for sustainable and eco-friendly nanoparticle production. Plant extracts rich ...
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Gold nanoparticles (AuNPs) have wide-ranging applications across scientific disciplines and industries. However, its conventional synthesis methods pose environmental and health risks, prompting the rise of green chemistry for sustainable and eco-friendly nanoparticle production. Plant extracts rich in bioactive compounds capable of reducing and capping nanoparticles have emerged as promising alternatives. Among these sources, Aloe vera, renowned for its diverse phytochemicals, presents an attractive avenue for nanoparticle synthesis devoid of hazardous reagents. This study delves into the one-step green synthesis of AuNPs employing aloe vera extract and examines their antibacterial efficacy against Gram-positive and Gram-negative bacteria. The synthesized AuNPs exhibited a reddish-purple color with localized surface plasmon resonance peaks at 529 nm, 535 nm, and 541 nm, corresponding to varying gold precursor concentrations (0.1 mM, 0.3 mM, and 0.5 mM). FTIR analysis confirmed the presence of bioactive compounds involved in the reduction and capping of AuNPs. Characterization via Transmission Electron Microscopy showed spherical AuNPs ranging from 10 nm to 39 nm in diameter, with stability indicated by zeta potential values of -37.3 mV, -28.7 mV, and -24.7 mV for the respective concentrations. Notably, AV-AuNPs demonstrated significant antibacterial activity, with inhibition zones of 34 mm against E. coli and 18 mm against B. subtilis, attributed to their ability to penetrate bacterial membranes and induce cell lysis.
Research Article
Polymer Composite
S. Manjunatha
Abstract
Nano-sized inorganic oxide materials dispersed polymers constitute a special class of composite materials that improve the properties of the base polymer. The way of designing the composite materials by fine dispersion of inorganic nanofillers in polymers leads to special properties and applications. ...
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Nano-sized inorganic oxide materials dispersed polymers constitute a special class of composite materials that improve the properties of the base polymer. The way of designing the composite materials by fine dispersion of inorganic nanofillers in polymers leads to special properties and applications. Metal oxide-based polymer nanocomposite materials integrate the science and technology of materials in terms of enhanced properties in comparison with basic materials. A bimetallic oxide material like nanosized cobalt nickelate (CoNiO2) is considered as an inorganic filler in polyaniline for its composite material. CoNiO2 was synthesized by microwave-assisted route using polyvinyl alcohol (PVA) as a fuel. The in-situ chemical oxidation polymerization method was adopted for the synthesis of nanosized cobalt nickelate dispersed polyaniline nanocomposite (PANI/CoNiO2) sample. Structural characterization of the derived nanocomposite sample was studied by employing X- ray diffraction (XRD) tool and morphology by Scanning Electron Micrograph (SEM) tool respectively. Fourier transform-Infrared (FT-IR) instrumentation is used to know the bonding nature of the sample. The presence of metal oxygen confirms the sample. Absorption behavior was analyzed by UV-vis study. The presence of metal components is confirmed by EDX analysis. The thermal behavior of the prepared polymer composite sample was carried out to know its thermal behavior.
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