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 ...
Read More
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.
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 ...
Read More
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.
Nanomaterials & Nanotechnology
Stella C; Ramachandran K
Abstract
Undoped and Co3O4-loaded (5, 10, and 15 at.%) SnO2 nanoparticles were prepared by a simple co-precipitation method. X-ray diffraction (XRD) study confirmed the presence of tetragonal phase of SnO2 and cubic stage of Co3O4 in accumulation to this the preferred orientation and texture coefficient were ...
Read More
Undoped and Co3O4-loaded (5, 10, and 15 at.%) SnO2 nanoparticles were prepared by a simple co-precipitation method. X-ray diffraction (XRD) study confirmed the presence of tetragonal phase of SnO2 and cubic stage of Co3O4 in accumulation to this the preferred orientation and texture coefficient were derived. The texture coefficient of (200) plane increases with parallel decrease in (110) plane, which indicate the development of voids like vacancies along (110) direction. Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) analyses recognized the uniform dispersion of spherical shaped nanoparticles. EDS analysis confirmed the impurity absence in the prepared samples. UV-Vis absorption analysis confirmed that the optical band gap will get red shifted from bulk which is due to the agglomeration of nanoparticles and also due to the influences of Co3O4. The absorption peaks broadens after loading Co3O4 which indicate the surface related defects in the samples. The refractive indices derived from the band gap values had confirmed the fiber-optic sensor working under the leaky mode operation. Vibrating sample magnetometer (VSM) results confirmed the behavior of ferromagnet in pure SnO2 and antiferromagnet stage in Co3O4 loaded SnO2. The undoped SnO2 with room temperature ferromagnetism (RTFM) shows better sensitivity. The sensitivity of SnO2 and Co3O4 loaded SnO2 samples were 0.076 and 0.084, respectively. The enhanced sensitivity of Co3O4 loaded SnO2 was due to the high catalytic activity of Co3O4.
Nanomaterials & Nanotechnology
S S Patil; V L Patil; AK Tawade; KK Sharma; TD Dongale; RM Mane; AK Bhosale; SA Vhanalkar
Abstract
Supercapacitors are emerging as an alternative to batteries due to their high-power density, low charging time, safety, electrochemical stability, and long cycle life and manganese dioxide (MnO2) is one of the best electrode materials to prepare supercapacitor. In this regard, the MnO2 as an electrode ...
Read More
Supercapacitors are emerging as an alternative to batteries due to their high-power density, low charging time, safety, electrochemical stability, and long cycle life and manganese dioxide (MnO2) is one of the best electrode materials to prepare supercapacitor. In this regard, the MnO2 as an electrode material was synthesized by using the simplistic electrodeposition method and various characterization techniques were carried out to investigate their physicochemical properties. The scanning electron microscopy illustrates the interconnected nano-wall like morphology of MnO2 thin films, resulting in a larger surface area. This morphology is beneficial for providing more active sites for charge storage and hence leads to a higher capacitance. Therefore, the nano-wall like structure of MnO2 thin films were utilized for the electrochemical measurements and it revealed higher specific capacitance at about 465 F/g for low scan rate of 10 mV/s. Furthermore, even after 500 cycles of voltammetry, the MnO2-based supercapacitor exhibits a higher cycling stability of about 98%.
Nanomaterials & Nanotechnology
Avadhesh Kumar Yadav
Abstract
In the past few decades, lanthanum ferrite has grown the importance in research due to attractive LPG/ humidity sensing and photolytic applications. In present study, the perovskite lanthanum ferrite was synthesized via solid state reaction route for three compositions by varying La/Fe ratio. The synthesized ...
Read More
In the past few decades, lanthanum ferrite has grown the importance in research due to attractive LPG/ humidity sensing and photolytic applications. In present study, the perovskite lanthanum ferrite was synthesized via solid state reaction route for three compositions by varying La/Fe ratio. The synthesized samples were characterized by Fourier transform spectroscopy, UV-vis spectroscopy, X-ray diffraction and scanning electron microscopy. The crystallization of lanthanum ferrite is confirmed by X-ray diffraction studies. The average crystallite size was found to be 45-50 nm. Surface morphological study of synthesized samples shows the uniform growth of the particles and grain which leaves the pores during its inter connection. These pores act as gas adsorption sites. The optical band gap of synthesized LaFeO3 samples were found to be 3.91-4.03 eV. Prepared samples were investigated for humidity sensing application. The average sensitivity of synthesized lanthanum ferrite samples was found to be 10.18-11.46 MΩ/%RH. The average sensitivity varies with the composition of the sample.
Nanomaterials & Nanotechnology
Huda Abdullah; Norshafadzila Mohammad Naim; Mohamad Aiman Arif Awang Omar; Jian Xian Kang; Iskandar Yahya; Noorfazila Kamal; Norazreen Abd Aziz; Atiqah Mohd Afdzaluddin; Noraziah Mohammad Zin; Mohd Hafiz Dzarfan Othman; Wing Fen Yap
Abstract
Carbon nanotubes (CNTs) are particularly attractive for use in sensors for environmental and health monitoring. This study proposes a new approach in developing polymer-metal-based sensor for E. coli detection by using CNTs incorporation. PANI-SnO2 nanocomposite thin films were combined with CNTs to ...
Read More
Carbon nanotubes (CNTs) are particularly attractive for use in sensors for environmental and health monitoring. This study proposes a new approach in developing polymer-metal-based sensor for E. coli detection by using CNTs incorporation. PANI-SnO2 nanocomposite thin films were combined with CNTs to be fabricated as biosensing devices. PANI-(SnO2)1-x-CNTx nanocomposite thin films were synthesized using sol-gel method and deposited on a glass substrate by spin coating technique. The prepared thin films were characterized by X-ray diffraction (XRD), field scanning electron microscopy (FESEM), atomic field microscopy (AFM) and ultraviolet-visible (UV-vis) spectroscopy. The sensitivity performance of PANI-(SnO2)1-x-CNTx nanocomposite thin films were conducted by using current-voltage (I-V) measurements. From the results, XRD patterns show the appearance of PANI, SnO2 and C peaks and the increasing crystallite size with the increasing of CNT concentration. FESEM images show the spherical shape of SnO2 and the nanotubes of carbon in the diameter size range 30 – 100 nm and 150 – 220 nm respectively. AFM analysis has found out the roughness parameter has increased when CNT percentage was increased. The peaks from UV-Vis absorbance bands indicated the presence of CNT and SnO2 at wavelength 270 nm and 370 nm respectively. From I-V measurement of the sensor, PANI-(SnO2)1-x-CNTx with x = 0.03 performed the highest sensitivity which is 16.32%. The results demonstrate that the increasing of CNT concentrations was increasing the sensitivity of PANI-(SnO2)1-x-CNTx thin films towards E. coli.
Nanomaterials & Nanotechnology
Avadhesh Kumar Yadav
Abstract
Materials science is a fast developing field of research in which a lot of advancements have been reported in few decades. The progress in materials science is essential due to its wide range of applications in solid state fuel cells, display materials, solar cells, energy storage devices, automotive ...
Read More
Materials science is a fast developing field of research in which a lot of advancements have been reported in few decades. The progress in materials science is essential due to its wide range of applications in solid state fuel cells, display materials, solar cells, energy storage devices, automotive sectors, electronics and environment, mechanical, medical & aerospace industries. Doping and substitutions in host materials are excellent ways of changing the properties of any materials. There are two main forms of materials, thin film and bulk, which are used in research. These two forms of materials are synthesized by two basic approaches, named as top-down and bottom-up. Bottom-up and top-down approaches are comprised of several synthesis methods, e.g., solid state reaction method, hydrothermal method, co-precipitation method, sol gel method, auto-combustion method, melt quench method, evaporation method, sputtering method, pulse laser deposition method, spin coating method and spray pyrolysis method. Each synthesis method has its unique procedure as well as merits and demerits. The solid state reaction route is one of the simplest synthesis method, which requires heating of the materials which were grounded for homogeneous mixing of the various oxide ingredients. The bulk and thin films at low reaction temperatures were prepared by sol-gel synthesis route which provides the high purity products. Co-precipitation method provides homogenous particle size which is a very energy efficient method. Thus, the synthesis method is an essential factor for materials science and nanotechnology research. The present article is an attempt to review the synthesis methods and their merits or demerits.
Nanomaterials & Nanotechnology
Rekha S; Sreelakshmi P S; Akhila V S; Amrutha R; Anila E I
Abstract
Green synthesis of nanoparticles has attracted great interest in recent years because it offers a cost effective and environment friendly method for the synthesis of nanoparticles. Calcium oxide (CaO) nanoparticles have potential applications in catalysis, wastewater treatment ...
Read More
Green synthesis of nanoparticles has attracted great interest in recent years because it offers a cost effective and environment friendly method for the synthesis of nanoparticles. Calcium oxide (CaO) nanoparticles have potential applications in catalysis, wastewater treatment and biomedicine. In the present study, CaO nanoparticles are synthesized by an eco-friendly green synthesis via thermal decomposition of eggshells which is a common waste material from households and restaurants. The synthesized nanoparticles were subjected to characterization using X-ray diffractogram (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared (FTIR) spectroscopy, photoluminescence (PL) spectroscopy and UV-vis spectroscopy. The structural studies confirmed the formation of cubic, crystalline and irregularly shaped nanoparticles. FTIR and EDX spectroscopy indicated intensive peaks attributed to the presence of calcium and oxygen atoms in the prepared samples. The PL emission spectra of CaO nanoparticles consisted of a broad peak for an excitation wavelength of 320 nm. The antibacterial activity of green synthesized CaO nanoparticles was investigated using gram-positive Staphylococcus aureus and gram-negative E.coli bacteria. The studies showed that the prepared nanoparticles exhibit antibacterial property.
Nanomaterials & Nanotechnology
Kasturee Hajra; Dipak Maity; Sumit Saha
Abstract
Metal Oxide Nanoparticles (MONPs) have become an important section of nanoparticles, and these nanomaterials have been utilized in different application fields. Thus, it’s very important to understand the major and feasible synthesis methods that are involved during the production of MONPs. In ...
Read More
Metal Oxide Nanoparticles (MONPs) have become an important section of nanoparticles, and these nanomaterials have been utilized in different application fields. Thus, it’s very important to understand the major and feasible synthesis methods that are involved during the production of MONPs. In our review, we are highlighting some major processes for their synthesis and morphology. This review highlights the status, potential, challenges, and feasibility of different processes like sol-gel, CVD, thermal, flame spray, biological synthesis, and other major techniques to synthesize and their applications. Synthesis of nanomaterial through environmentally friendly and greener routes, which greatly impacts different applications, has also been studied as it has received massive attention as a sustainable, feasible, reliable, and cost-effective route in different fields. These artificially created MONPs exhibit distinct physical and chemical characteristics owing to their substantial surface area and nanoscale dimensions. Their exceptional size, shape, and structure further influence their reactivity, resilience, and diverse properties. Thanks to these attributes, they find wide-ranging uses in commercial and domestic applications, such as catalysis, antimicrobial treatments, bio-sensors, electro-sensors, as well as agriculture and various other significant fields. This review paper states major applications of these MONPs have great aspects and potential in the future and will help researchers gain further insights into these fields.
Nanomaterials & Nanotechnology
Ananya Kashyap; Madhubala Kumari; Sumant Kumar; Samira Nazma; Koel Mukherjee; Dipak Maity
Abstract
Biosynthesized metal oxide nanoparticles are used as nano-fertilizers for sustainable agriculture as they have proven to be promising agents in increasing the germination rates and plant growth rate. Biosynthesis of copper oxide nanoparticles (CuO-NPs) was done for the first-time using extract of Mangifera ...
Read More
Biosynthesized metal oxide nanoparticles are used as nano-fertilizers for sustainable agriculture as they have proven to be promising agents in increasing the germination rates and plant growth rate. Biosynthesis of copper oxide nanoparticles (CuO-NPs) was done for the first-time using extract of Mangifera indica leaves. Effects of as-synthesized CuO NPs on the seed germination of two legume seeds are investigated at different concentrations (0 - 2.5 mg/ml). UV-Vis and EDX analysis confirm the formation of CuO NPs & FESEM images revealed spherical shape of NPs with particle size ranging from 105nm to 155nm. CuO-NPs also revealed to be highly stable in aqueous suspension with zeta potential value -21.1mV. Germination rate, root /shoot growth and protein estimated of Cicer arietinum and Vigna radiata seeds found to be highest at 2.5mg/ml and 1mg/ml concentration, respectively. Negative impact on germination rate and root/shoot growth was observed due to toxic effects when CuO-NPs were applied at higher concentration 2.5mg/ml to Vigna radiata seeds. Thus, it is concluded that optimum concentration of biosynthesized CuO-NPs can be used to enhance the growth of leguminous seeds because of their possible interaction with the proteins and their up-regulation as confirmed by bioinformatics studies and molecular docking of protein.
Nanomaterials & Nanotechnology
Honghong Wu; Zhaohu Li
Abstract
As a chronic stress, salinity is a global issue threatening agricultural production. Salinity stress limits plant yield and product quality. In terms of providing more tools to help to secure food supply in future, new approaches which can improve crop salt tolerance are encouraged. Nanobiotechnology ...
Read More
As a chronic stress, salinity is a global issue threatening agricultural production. Salinity stress limits plant yield and product quality. In terms of providing more tools to help to secure food supply in future, new approaches which can improve crop salt tolerance are encouraged. Nanobiotechnology is a promising approach to improve plant salt tolerance. Nano-improved salt tolerance is widely reported in many plant species, including rice, rapeseed, cotton, cucumber and Arabidopsis etc. To better facilitate the usage of nanomaterials in agricultural production, understanding mechanisms behind nano-improved plant salt tolerance could be a useful approach. In this review, we summarized the known mechanism behind nano-enabled plant salt tolerance, from maintaining ROS homeostasis and Na+/K+ ratio to the modulation at the level of hormones and gas signaling molecules. Also, new possible mechanisms of nano-enabled plant salt tolerance are discussed. Overall, this manuscript aims to help people to better understand the mechanisms behind nano-enabled plant salt tolerance.
Nanomaterials & Nanotechnology
Pan Zhang; Wanchun Guo
Abstract
The noble metal nanoparticles sandwiched between the stable inorganic core and the thin polymer shell could not only enhance their stability, but also cut short the diffusion route of the outside reactants through polymer shell toward encapsulated noble metal nanoparticles, which has drawn great attention. ...
Read More
The noble metal nanoparticles sandwiched between the stable inorganic core and the thin polymer shell could not only enhance their stability, but also cut short the diffusion route of the outside reactants through polymer shell toward encapsulated noble metal nanoparticles, which has drawn great attention. However, weak compatibility among inorganic core, polymer shell, and noble metal nanoparticles makes the preparation of noble metal-confined hybrid catalysts complicated, which limits the popular application of these noble metal-based catalysts. A facile method has developed to fabricate core-shell Fe2O3@PEDOT/Pt nanocatalyst with tiny Pt nanoparticles highly dispersed in the polymer shell by one-step simultaneous redox deposition strategy. The confinement effect and strong coordination ability of the thin sulfur-enriched polymer shell prevents the migration and agglomeration of Pt nanoparticles during the catalytic process and improves the stability of the catalyst. The catalyst shows outstanding catalytic activity and relatively good stability towards the reduction of nitroaromatic compounds. The simple method solves the problem of poor compatibility between the inorganic core, the polymer shell, and the noble metal nanoparticles confined in the shell material to some extent. Furthermore, our strategy could be extended to one-step preparation of Fe2O3@Polymer@Pt hybrid materials with core-shell structure.
Nanomaterials & Nanotechnology
Arunkumar M Lahgashetty; Jayasurya K H; Swathi M; Netravati G; Leelanagalaxmi H; Chitralekha Alur; Sangappa K Ganiger
Abstract
Synthesis of nanosized materials integrates the materials synthetic technology. Nanosized bimetallic oxides constitute class materials in concerned with its applications. The present work reports the synthesis of barium stannate (BaSnO3)nanopowder by self-propagating combustion reaction using polyvinyl ...
Read More
Synthesis of nanosized materials integrates the materials synthetic technology. Nanosized bimetallic oxides constitute class materials in concerned with its applications. The present work reports the synthesis of barium stannate (BaSnO3)nanopowder by self-propagating combustion reaction using polyvinyl alcohol (PVA) as a fuel. Initially basic oxides barium oxide (BaO) and tin oxide (SnO2) are also prepared by combustion route. Further barium stannate-PVA nanocomposite (BaSnO3-PVA) is prepared by dispersion of BaSnO3 material into PVA matrix using solvent casting method. Structural characterization of oxide and nanocomposite was studied by X-ray diffraction (XRD) tool and bonding nature by Fourier transfer infrared study (FT-IR) respectively. Thermal behavior of both the sample is well studied by thermo gravimetric analysis (TGA). Electrochemical study of the sample is carried out by cyclic voltammetry (CV) instrumentation. Varied morphology and particle size of the sample was analysed through Transmission electron microscope (TEM) tool.
Nanomaterials & Nanotechnology
Ibrahim Maamoun; Omar Falyouna; Islam Mir Shariful; Ramadan Eljamal; Khaoula Bensaida; Kazuya Tanaka; Kohei Tokunaga; Osama Eljamal
Abstract
For several decades, arsenic (As) contamination of water was considered as an issue of great concern. In this study, magnesium hydroxide coated iron nanoparticles (nFe0@Mg(OH)2) were developed for enhancing arsenic removal from aqueous solutions. Several parameters were investigated, including Mg/Fe ...
Read More
For several decades, arsenic (As) contamination of water was considered as an issue of great concern. In this study, magnesium hydroxide coated iron nanoparticles (nFe0@Mg(OH)2) were developed for enhancing arsenic removal from aqueous solutions. Several parameters were investigated, including Mg/Fe coating ratio, nFe0@Mg(OH)2 dosage, initial pH, reaction temperature, and initial As(V) concentration. The characteristics of the synthesized materials were studied using different techniques, such as transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray absorption near edge structure (XANES). Results indicated the superiority of the highest Mg/Fe coating ratio (100%) to the other lower ratios in As(V) removal, corresponding to the adsorption contribution of Mg(OH)2 coating shell. Furthermore, nFe0@Mg(OH)2-100% could efficiently achieve around 100 % final As(V) removal efficiency at wide pH and temperature ranges (3.0 – 9.0, and 25 – 75 oC), at a low dosage of 0.5 g/L, reflecting the high applicability of the proposed material. Mg(OH)2 coating enhanced the anti-aggregation effect of the magnetic nanoparticles, which was confirmed by TEM measurements. Kinetics, thermodynamic, and isotherm analyses depicted that pseudo-second-order was the best model to describe the kinetics data, the endothermic nature of the reaction, and a maximum Sips sorption capacity of 89.97 mg/g (following Sips isotherm model), respectively.
Nanomaterials & Nanotechnology
Parvathy Bhaskar; Veena M G; Madhukar B S
Abstract
Pure and rare earth metal [cerium (Ce) and thorium (Th)-doped zinc oxide (ZnO)] nanostructures were prepared by solution combustion synthesis by making use of metal nitrates and glycine as precursors in alkaline medium. The average crystal size was examined using Powder X-Ray Diffraction (PXRD) which ...
Read More
Pure and rare earth metal [cerium (Ce) and thorium (Th)-doped zinc oxide (ZnO)] nanostructures were prepared by solution combustion synthesis by making use of metal nitrates and glycine as precursors in alkaline medium. The average crystal size was examined using Powder X-Ray Diffraction (PXRD) which showed sizes of 45 nm for pure ZnO sample,17.9 nm and 20 nm for Ce and Th-doped ZnO samples respectively. Accordingly, the synthesized samples were confirmed to be polycrystalline from High-Resolution Transmission Electron Microscopy (HRTEM), Selected Area Electron Diffraction (SAED) and X-Ray Diffraction (XRD) analyses. Field Emission Scanning Electron Microscopy coupled with Energy Dispersive X-Ray Spectroscopy (FESEM / EDX) confirmed the existence of the respective components in the synthesized samples. The Ultra Violet – Visible - Near Infra-Red (UV – Vis - NIR) Spectroscopy showed the characteristic absorption spectra of the samples. The surface topography of the prepared samples was studied by Atomic Force Microscopy (AFM). To further confirm the chemical composition and binding energy, X-Ray Photoelectron Spectroscopy (XPS) was employed.
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 ...
Read More
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.
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 ...
Read More
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.
Carbon Materials and Technology
Carsten Strobel; Carlos Chavarin; Sebastian Leszczynski; Karola Richter; Martin Knaut; Johanna Reif; Sandra Voelkel; Matthias Albert; Christian Wenger; Johann Wolfgang Bartha; Thomas Mikolajick
Abstract
A new kind of transistor device with a graphene monolayer embedded between two n-type silicon layers is fabricated and characterized. The device is called graphene-base heterojunction transistor (GBHT). The base-voltage controls the current of the device flowing from the emitter via graphene to the collector. ...
Read More
A new kind of transistor device with a graphene monolayer embedded between two n-type silicon layers is fabricated and characterized. The device is called graphene-base heterojunction transistor (GBHT). The base-voltage controls the current of the device flowing from the emitter via graphene to the collector. The transit time for electrons passing by the ultrathin graphene layer is extremely short which makes the device very promising for high frequency RF-electronics. The output current of the device is saturated and clearly modulated by the base voltage. Further, the silicon collector of the GBHT is replaced by germanium to improve the device performance. This enabled the collector current to be increased by almost three orders of magnitude. Also, the common-emitter current gain (Ic/Ib) increased from 10-3 to approximately 0.3 for the newly designed device. However, the ON-OFF ratio of the improved germanium based GBHT has so far been rather low. Further optimizations are necessary in order to fully exploit the potential of the graphene-base heterojunction transistor.
Thin Films, Materials Surface & Interfaces
Giorgos Papadimitropoulos; Angelika Balliou; Dimitris Kouvatsos; Dimitris Davazoglou
Abstract
The gas sensing properties of porous hot-wire MoS2 (hwMoS2) thin films have been studied. The films were deposited on oxidized silicon substrates by heating a molybdenum filament in a vacuum chamber in H2S environment. The samples remain at room temperature during the deposition and the grown films are ...
Read More
The gas sensing properties of porous hot-wire MoS2 (hwMoS2) thin films have been studied. The films were deposited on oxidized silicon substrates by heating a molybdenum filament in a vacuum chamber in H2S environment. The samples remain at room temperature during the deposition and the grown films are amorphous and porous. Reversible changes of the current values in the hwMoS2 films were observed due to the presence or upon removal of chemical gases such as hydrogen (H2) and carbon monoxide (CO). The sensitivity, was dependent on the concentrations of the gases and the temperature of measurement. The response time was found to be comparable to the recovery time and of the order of a few seconds. It is important to note that the surface of the hwMoS2 films was not activated with any catalyst, which is a common practice in most thin films used for gas sensing, rendering our process simpler and cheaper.
Nanomaterials & Nanotechnology
Pramod Kumar Yadawa; Navin Chaurasiya; Sachin Rai
Abstract
All the elastic, mechanical and thermal properties of Gd-doped ZnO nanorods (NRs) have studied using interaction potential model. Gd-doped ZnO nanorods are hexagonal wurtzite structure. The characteristic features of elastic characteristics of Gd-doped ZnO NRs imply that this is mechanically stable. ...
Read More
All the elastic, mechanical and thermal properties of Gd-doped ZnO nanorods (NRs) have studied using interaction potential model. Gd-doped ZnO nanorods are hexagonal wurtzite structure. The characteristic features of elastic characteristics of Gd-doped ZnO NRs imply that this is mechanically stable. For mechanical characterization, bulk modulus (B), shear modulus (G), Young's modulus (Y), Pugh's ratio (B / G), Poisson’s ratio and anisotropic index are evaluated using second order elastic constants. For the investigation of anisotropic behaviour and thermophysical properties, ultrasonic velocities and thermal relaxation time have been also calculated along with different orientations from the unique axis of the crystal. The mechanical properties of the Gd-doped ZnO nanorods are better than at 6% Gd amount due to minimum attenuation. The obtained results are analyzed to explore the characteristic of ZnO nanorods. Computed elastic, ultrasonic and thermal properties are correlated to evaluate the microstructural behaviour of the materials useful for industrial applications
Nanomaterials & Nanotechnology
Praveena G; Mohammed E.M.; Viji C.; Shyam Kumar S.
Abstract
Nickel ferrite (NiFe₂O₄) nanoparticles were synthesized using the sol-gel auto combustion method, and the powdered samples were calcined at two temperatures, 100°C and 200°C. The structure of nickel ferrite nanoparticles was determined using X-ray diffraction (XRD) patterns. The nickel ferrite ...
Read More
Nickel ferrite (NiFe₂O₄) nanoparticles were synthesized using the sol-gel auto combustion method, and the powdered samples were calcined at two temperatures, 100°C and 200°C. The structure of nickel ferrite nanoparticles was determined using X-ray diffraction (XRD) patterns. The nickel ferrite nanoparticle size was calculated using the Debye-Scherrer formula and was found to be 15.53 nm and 17.14 nm for 100 °Cand 200 °C. Field Emission Scanning Electron Microscopic (FESEM) analysis reveals that the samples exhibit spherical morphology with crystalline in nature and also show some agglomeration. The phase formation of nickel ferrite nanoparticles was further confirmed from the energy dispersive x-ray (EDAX) spectra which shows strong peaks for the existence of all the elements in it. The work investigates the magnetic properties of the samples and both the samples exhibit ferromagnetic behavior. The optical band gap obtained for the samples is 2.5 and 2.6 eV for N1 and N2 samples. The antimicrobial activity especially the anti-algal effect of NiFe₂O₄ nanoparticles on freshwater microalgae Chlorella pyrenoidosa in a dose-dependent manner is also reported.
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)