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.
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.
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.
G. Usha; R. Vasanthi; D. Reuben Jonathan; K.S. Ezhilarasi; M. Krishna Priya
Abstract
A novel chalcone derivative, (2E)-3-(3, 4 dimethoxy phenyl)-1-(1-hydroxy-2 naphthyl)prop-2-en-1-one (DHNP), C21H18O4, has been synthesized from the mixture of 4-hydroxy acetophenone (0.05mol) and 4-hydroxy-3-ethoxybenzaldehyde (0.05mol) by Claisen-Schmidt reaction mechanism. The structural ...
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A novel chalcone derivative, (2E)-3-(3, 4 dimethoxy phenyl)-1-(1-hydroxy-2 naphthyl)prop-2-en-1-one (DHNP), C21H18O4, has been synthesized from the mixture of 4-hydroxy acetophenone (0.05mol) and 4-hydroxy-3-ethoxybenzaldehyde (0.05mol) by Claisen-Schmidt reaction mechanism. The structural features of the grown crystal were elucidated by single X-ray diffraction (XRD) studies which confirm the title compound, belongs to the monoclinic system with the P21/n space group. Functional groups, the number of unique proton and carbon environments were identified using FT-IR, 1H, and 13C NMR spectral investigation. The optical behavior of the crystal was analyzed by UV-Vis absorption studies, and the value of the optical band gap energy (𝐸𝑔) of the crystal is found to be 3.386eV. The Photoluminescence (PL) spectrum of the compound indicates the green to yellow light emission in the visible region. By employing thermogravimetric analysis (TGA), the thermal stability of crystal and the dehydration and decomposition nature were found. The Coats and Redfern relation was applied to evaluate the kinetic and thermodynamic parameters. Mechanical properties such as the Hardness (HV), Meyer's index (n), Newtonian resistance pressure (W), load independent constant (b), and elastic stiffness constant (Cij) were calculated by performing a Vickers hardness test on the compound and found to exhibits an excellent mechanical power.
Composite Materials
Daniel Dubecky; Vincent Kvocak; Michala Weissova
Abstract
Composite polymer-concrete beams represent new modern structures that can take an advantage of the polymer's practical tensile properties and combine them with the concrete's favourable compressive properties. Drawing on this knowledge, a set of polymer beams acting compositely with a concrete slab was ...
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Composite polymer-concrete beams represent new modern structures that can take an advantage of the polymer's practical tensile properties and combine them with the concrete's favourable compressive properties. Drawing on this knowledge, a set of polymer beams acting compositely with a concrete slab was designed and manufactured. The aim of the research was to utilise the low weight and high strength of the polymer I-sections and combine them with the high stiffness of the concrete slab, which forms the upper part of the cross-section. The advantage of fibre-reinforced polymer (FRP) beams is their anisotropy, where the strength of the material is increased by placing the fibres uniformly in one direction, and the composite elements are then stressed in the most reinforced direction. To ensure the interaction between the polymer element and the concrete slab, strip shear connectors of a precisely defined shape were developed and utilised. The designed composite beam simulates a pre-cast component that can be applied in bridge structures for short and medium spans. The pre-cast beams were subjected to four-point bending. Apart from the overall deflections of the structure, the stresses in the cross-section of the composite material and the relative deformations/strains on the surface of the concrete part of the cross-section were monitored during the test. The whole experiment yielded new results in both laboratory and theoretical respects, not only regarding the interaction of materials with distinct characteristics but also the properties of composites per se.
Structural & Engineering Materials
Beata Stankiewicz
Abstract
Depending on the type of the load which affects the durability and design life glass fibre reinforced polymer (GFRP) structures should be designed so as to take into account as first of all the chemical-physical conditions in which the structure is used including: ultraviolet (UV) radiation, temperature ...
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Depending on the type of the load which affects the durability and design life glass fibre reinforced polymer (GFRP) structures should be designed so as to take into account as first of all the chemical-physical conditions in which the structure is used including: ultraviolet (UV) radiation, temperature influences, humidity, water and chemicals. The results presented herein provide a predictions regarding of the mechanisms involved in the ageing of GFRP pultruded bridge profiles and predicting the property micro scale changes with time and remaining service life of GFRP under real environmental degradation impacts and during simulation laboratory conditions. The outermost layers of FRP (fibre reinforced polymer) composites are damaged mostly because of UV radiation. Radiation also induces remarkable microstructural changes depending on wavelength and intensity, and oxygen availability, eventually leading to polymer chain scission. A scanning electron microscope (SEM) was used to investigate the degradation mechanism of the GFRP samples subjected among others to UV radiation and water vapor condensation. Glass fibre-reinforced polymer GFRP pultruded profiles have great potential in the construction industry, presenting several advantages comparing with traditional materials, among which, the potentially improved durability under environmental influents.
Carbon Materials and Technology
Zacharias Fthenakis; Antonios Fountoulakis; Ioannis Petsalakis; Nektarios Lathiotakis
Abstract
This work is part of a systematic study on the energy barriers for the permeation of several molecules, like He, H2, CO, CO2, H2O, NH3, CH4 etc, through nanoporous single layer graphene, having pores with different shape, size, and type. In the present work, we focus on the permeation of CO2 through ...
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This work is part of a systematic study on the energy barriers for the permeation of several molecules, like He, H2, CO, CO2, H2O, NH3, CH4 etc, through nanoporous single layer graphene, having pores with different shape, size, and type. In the present work, we focus on the permeation of CO2 through graphene pores which are constructed when neighboring carbon atoms of the graphene layer are removed from the structure, and nitrogen atoms have replaced the carbon atoms in the boundary of the pore. The energy barriers for each different pore are calculated using 2 different ReaxFF potentials along a path which the molecule would ideally follow in order to pass from the one side of the membrane to the other through the pore. Using the calculated values of the energy barriers, we estimate permeances by employing the kinetic theory of gasses. We give estimates for the preferable sizes and structures of the pores for permeability and demonstrate the ability of nanoporous graphene for CO2 separation.
Nanomaterials & Nanotechnology
Miranda Benavides; Denis Leonardo Mayta; Fernando Alonso Cuzziramos; Gerhard Paul Rodriguez; Fredy Alberto Huaman-Mamani
Abstract
The traditional method of manufacturing SiC compounds is associated with a serious environmental problem, mainly due to the need for large amounts of energy (generally derived from oil) to reach processing temperatures (typically above 2500 ºC). In addition, the chemical reaction that gives rise ...
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The traditional method of manufacturing SiC compounds is associated with a serious environmental problem, mainly due to the need for large amounts of energy (generally derived from oil) to reach processing temperatures (typically above 2500 ºC). In addition, the chemical reaction that gives rise to the formation of SiC has CO and CO2 as by-products. Therefore, in this work an alternative method to manufacture SiC/Si composites using waste from the wood industry as the main raw material was developed. SiC/Si composites were fabricated by infiltration of molten silicon into carbon preforms at 1500 °C. The carbon preforms were obtained by pyrolysis (in an inert Ar atmosphere) of four types of resin-carbon mixtures. The carbon used in the mixtures was obtained by pyrolysis of sawdust powder.The mechanical and thermomechanical behavior in uniaxial compression was studied at a constant compression rate of 0.05 mm/min at different temperatures (ambient, 1100 °C and 1400 °C). The maximum resistance values found were in the range of 58 and 384 MPa, while the Young's modulus values were between 40 and 120 GPa. The porosity found in the materials was between 1 and 4%. Finally, the fabricated compounds presented a homogeneous microstructure of interconnected silicon carbide in gray contrast and dispersed and unconnected whitish phases of uniformly distributed silicon.
Experimental Techniques
Khaled Saad; Andras Lengyel
Abstract
This research presents a parametric three-dimensional finite element study on the effects of closely spaced knots and related fibre deviations on the flexural failure mechanism of wood. The model considers the effects of the position of the knots along the beam's longitudinal and vertical axis. The numerical ...
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This research presents a parametric three-dimensional finite element study on the effects of closely spaced knots and related fibre deviations on the flexural failure mechanism of wood. The model considers the effects of the position of the knots along the beam's longitudinal and vertical axis. The numerical models were validated by bending tests performed on six beams. The actual three-dimensional geometry of knots and related fibre deviations were determined accurately based on an algorithm proposed previously by the authors. The elastic-plastic constitutive law of Nordic Spruce wood was considered based on the Hill anisotropic model. The failures were numerically predicted with the help of the Tsai-Wu failure criterion. The validated numerical models can also be used based on visual inspections. The user needs only to define the position and size of the knots and the space between them. Moreover, the model allows defining different fibre patterns in the knot vicinity. The model considers a fixed knot located in the tension zone at the mid-span of the beam and a moving knot adjusted at horizontal and vertical centre-to-centre distances d and v from the fixed one. Results revealed that regardless of the distance d (where v = 0), the failure will initiate at the same load levels for both knots. However, moving the adjacent knot diagonally (v not equal to 0) causes shear failure between the knots. The part of the clear wood between the knots is ineffective if the knots' centre-to-centre distance is less than three times the knot diameter.
Composite & Ceramic Materials
Vithal Muga; Vaishnavi Kammara; Venkataswamy Perala; Manasa Sunku; Ramaswamy Kadari; Hima Bindu Gaddameedi; Sudhakar Reddy Chandiri
Abstract
Doping of cations into wide bandgap semiconductors is an effective method of increasing photocatalytic activity. This work aims to find out how dopant ions like Ag+, Cu2+ and Sn2+ affect the structural, optical and photocatalytic properties of Li2GeTeO6. The parent Li2GeTeO6 (LGTO) was synthesized by ...
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Doping of cations into wide bandgap semiconductors is an effective method of increasing photocatalytic activity. This work aims to find out how dopant ions like Ag+, Cu2+ and Sn2+ affect the structural, optical and photocatalytic properties of Li2GeTeO6. The parent Li2GeTeO6 (LGTO) was synthesized by conventional solid-state method, whereas the Ag+, Cu2+ and Sn2+-doped Li2GeTeO6 were prepared by a simplistic ion-exchange method. Techniques such as XRD, FT-IR, SEM-EDS, N2 adsorption-desorption analysis, UV-Vis DRS, XPS, and PL were employed to examine the physico-chemical properties of the as-prepared materials and their photocatalytic activities on the degradation of methyl violet (MV) under visible light irradiation. The acquired photocatalytic activity results revealed that all doped samples displayed enhanced photocatalytic performance compared with parent LGTO. The Ag-LGTO had the best photocatalytic activity for MV degradation, with 68.6% degradation efficiency in 180 min of irradiation. Scavenging experiments were carried out to determine the role of various active species generated on the surface of Ag-LGTO during the photocatalytic degradation of MV. The reusability and stability of Ag-LGTO up to five cycles against MV degradation were also investigated. A photocatalytic mechanism for MV degradation over the Ag-LGTO sample was also proposed based on the findings described above.
Environmental & Green Materials
Ashutosh Tiwari
Abstract
Climate change has made the human ecosystem uncertain. The eco-adaptation is contributing significantly to a progressive shift in the entire geographical region until and unless it reaches an equilibrium stage. It is critical to support innovative, cleaner public transportation and decarbonization in ...
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Climate change has made the human ecosystem uncertain. The eco-adaptation is contributing significantly to a progressive shift in the entire geographical region until and unless it reaches an equilibrium stage. It is critical to support innovative, cleaner public transportation and decarbonization in the carbon industries to create a sustainable world. Global organizations are developing strategies and agendas to contribute to the Sustainable Development Goals in various ways. The economic growth and well-being of the people require an understanding of the one world-one climate concept, and this in turn necessitates basic information for climate rejuvenation strategies in contemporary society.
Polymer Composite
Daily Maria Gallegos; Denis Mayta; Gerhard Paúl Rodriguez; Fredy Alberto Huaman; Fernando Alonso Cuzziramos
Abstract
The effect of the addition of alpaca fibers on the mechanical response of geopolymeric mortars was studied using uniaxial compression tests. The studied mortars were manufactured by mixing mining tailings, fine sand and variable percentages of alpaca wool fibers. The mechanical results show a higher ...
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The effect of the addition of alpaca fibers on the mechanical response of geopolymeric mortars was studied using uniaxial compression tests. The studied mortars were manufactured by mixing mining tailings, fine sand and variable percentages of alpaca wool fibers. The mechanical results show a higher degree of deformation, up to 6%, for the mortar mixtures with higher amounts of wool fiber in their composition, that is, the decrease in maximum compressive strength was demonstrated as the volume increased of added fibers, the values were from 32 to 9 MPa for samples with 0 and 8 % Vol. of added fibers, respectively. On the other hand, studies of the real density and the average porosity were carried out, obtaining values of 2.59 g/cm3 and 31 %, respectively. Additionally, the morphological analysis was carried out using microscopy in which a continuous binder geopolymer phase could be seen and within this phase a phase of sand and fibers.
Nanomaterials & Nanotechnology
Nizam Solangi; Sorath Solangi; Gul Naz; Ghulam Murtaza Mastoi
Abstract
A compact and intimate interfacial contact between the modified film and the conducting electrode is crucial for electrochemical biosensors. The direct drop-casting of nanomaterials onto the working electrode often fails to construct a compact interfacial arrangement, which results in sluggish electrode ...
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A compact and intimate interfacial contact between the modified film and the conducting electrode is crucial for electrochemical biosensors. The direct drop-casting of nanomaterials onto the working electrode often fails to construct a compact interfacial arrangement, which results in sluggish electrode kinetics. Here, we describe a simple and cost-effective strategy to produce CuO nanostructure using a modified hydrothermal route. The in-situ growth allowed the formation of a highly ordered interconnected network of sharp flakes configured in the form of large spheres with excellent ITO surface coverage. The CuO nanostructures were highly electrochemically active toward the oxidation of β–adrenergic agonists, i.e., formoterol fumarate (FF). The analytical ability was studied by comparison of the electrochemical behavior of ITO based electrode with its glassy carbon electrode counterpart. The binder-less CuO-based ITO electrode successfully determined FF with a detection window of 0.01 µM to 0.46 µM with practical application for real broiler feed samples collected from the local poultry farms in Hyderabad, Pakistan.
Composite Materials
Klaudia Hurtukova; Nikola Slepičková Kasálková; Dominik Fajstavr; Anna Kutová; Petr Slepička
Abstract
In this study, we prepared hybrid materials with C and Ag layers on the surface of polydimethylsiloxane polymer (PDMS). The prepared samples were subjected to thermal treatment and modification with high energy KrF excimer laser in single shot mode. The change in the surface morphology of the samples ...
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In this study, we prepared hybrid materials with C and Ag layers on the surface of polydimethylsiloxane polymer (PDMS). The prepared samples were subjected to thermal treatment and modification with high energy KrF excimer laser in single shot mode. The change in the surface morphology of the samples was investigated by Scanning Electron Microscopy (SEM), and the chemical composition of the prepared nanocomposites was studied by Energy Dispersive Spectroscopy (EDS). Finally, the samples were tested for antibacterial activity using two bacterial strains of Gram-positive S. epidermidis and Gram-negative E.coli. Antibacterial properties were observed on the prepared samples in both bacteria colonies.
Composite Materials
Anna Kutová; Ondřej Kvítek; Klaudia Hurtuková; Václav Švorčík
Abstract
Nowadays, new materials for the preparation of synthetic bone grafts are being sought after. Bones consist mainly of collagen fibres and hydroxyapatite crystals, so using synthetic grafts with a similar structure is logical. Therefore, a composite material was prepared by adding hydroxyapatite particles ...
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Nowadays, new materials for the preparation of synthetic bone grafts are being sought after. Bones consist mainly of collagen fibres and hydroxyapatite crystals, so using synthetic grafts with a similar structure is logical. Therefore, a composite material was prepared by adding hydroxyapatite particles in the cultivation medium of bacterial nanocellulose (in-situ method). The composites were dried via air-drying and lyophilization to obtain solid materials. The formation of the composite was confirmed by infrared spectroscopy, which showed cellulose (OH vibrations) as well as hydroxyapatite (PO43- vibrations) absorption bands. Energy dispersive X-ray spectroscopy showed presence of 14 wt% of calcium and 48 wt% of phosphorus in the composites. The structure of the hydroxyapatite crystals embedded in fibrous cellulose was observed by scanning electron microscopy. The higher porosity of the lyophilized samples was confirmed as well. Water contact angle of the air-dried composites was lower (25 ± 3.6)° compared to pure bacterial nanocellulose (30 ± 2.7)°. The mechanical strength of the air-dried composites was (20.3 ± 7.9) MPa. These results suggest the prepared material is promising for construction of synthetic bone grafts.
Composite Materials
Elguja Kutelia; Kusman Dossumov; Gaukhar Yergasiyeva; David Gventsadze; Nikoloz Jalabadze; Teimuraz Dzigrashvili; Lili Nadaraia; Olga Tsurtsumia; Manshuk Mambetova
Abstract
This study first demonstrated the possibility of the production of catalyst supports in the form of granules and tablets composed of nanoparticles of Fe atom cluster-doped CNTs using mini-mold forming and spark plasma sintering (SPS) techniques respectively. The pilot samples of the novel catalyst system ...
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This study first demonstrated the possibility of the production of catalyst supports in the form of granules and tablets composed of nanoparticles of Fe atom cluster-doped CNTs using mini-mold forming and spark plasma sintering (SPS) techniques respectively. The pilot samples of the novel catalyst system containing 3% NiO active phase, synthesized on the granulated Fe cluster-doped CNTs carrier, were tested to determine their catalytic activity and coking resistance in the DRM reaction, in a wide range of temperatures up to 900oC. The developed novel catalyst systems’ samples were characterized before and after the catalyst reaction using SEM, EDX, XRD, and AES methods. It is shown that the temperature dependence of the catalytic activity of the 3% NiO catalyst, supported on the granulated Fe cluster-doped CNTs carrier, revealed two characteristic temperature ranges with different rates of efficiency. Particularly, at high reaction temperatures, starting from 700oC, the conversion rates of methane and carbon dioxide (42.4% and 45.6% respectively) have more than doubled at 850oC. Starting from 850oC to 900oC the latter tends to exceed the carbon dioxide conversion rate, and at 900oC it amounts to 95%.
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