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Dielectric and Mechanical Properties of Local Commercial Single Walled Carbon Nanotubes for Medical Applications: A Practical Approach
Moustafa Hussein Moustafa
Issue:
Volume 7, Issue 1, March 2021
Pages:
1-5
Received:
10 December 2020
Accepted:
17 December 2020
Published:
22 January 2021
Abstract: Owing to their exceptional electrical and mechanical properties, low weights and availability of their synthesis and purification carbon nanotubes (CNTs) became the focus of scientists in many medical and electronic applications, and reinforcement of various materials. A close understanding of structure-properties of (CNTs) will be necessary for the development of carbon-nanotube applications. High stiffness and tensile strength of CNTs provide mechanical stability for electric nano-circuits formed by CNTs. Meanwhile, at earlier time of their application, researchers main concern was dedicated for preparation methods of CNTs. Eventually the structural and physical characteristics of CNTs became more attractive for scientist proper applications. Herein the current work introduce a practical approach for screening the dielectric and mechanical properties of local commercial purchased single walled carbon nanotubes for medical applications. Dielectric properties of CNTS were expressed in term of electrical relative permittivity, and electrical conductivity. The dielectric relaxation obeys ordinary alpha and beta relaxation of dielectrics at current frequency range. Besides the mechanical properties in term of dimetral tensile and compression strength that are expressed by Young’s modulus that is closer to graphite. As a results, we highly recommend these commercial (SWCNTs) from our local suppliers for further medical applications.
Abstract: Owing to their exceptional electrical and mechanical properties, low weights and availability of their synthesis and purification carbon nanotubes (CNTs) became the focus of scientists in many medical and electronic applications, and reinforcement of various materials. A close understanding of structure-properties of (CNTs) will be necessary for the...
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Structural, Morphological and Optical Properties of Spray Deposited Multi-doped (Ba, Sr, Mn, Fe and Ni) Compositionally Complex ZnO Thin Films
Mohammad Rahat Al Hassan,
Aungkan Sen,
Mohammad Khalid Hasan,
Mohammad Abdul Matin
Issue:
Volume 7, Issue 1, March 2021
Pages:
6-14
Received:
21 December 2020
Accepted:
31 December 2020
Published:
28 January 2021
Abstract: Configurational disorder due to high level multi element doping has gained huge attention from research community because of its possibility of unique phase stability as well as unusual functional properties. Based on this context extensive researches performed in recent decades to establish a new horizon of materials i.e. high entropy alloy and ceramics. Of-late, compositionally complex ceramics (CCCs) has been released as an extended form of high entropy ceramics (HECs) where compositional space has been broadened by consideration of both non-equimolecular compositions and relatively low entropy regions. This report aims to stabilize ZnO wurtzite phase at room temperature replacing the Zn-site with five metallic elements i.e. Ba, Sr, Mn, Fe, Ni in equimolecular ratio to impose configurational disorder in the ZnO lattice. Therefore, (BaxSrxMnxFexNix) Zn1-5xO (where x=0, 0.01, 0.02 and 0.03; the films are denoted hereby as ZO, 5DZO, 10DZO and 15DZO respectively) thin films were deposited by low cost spray pyrolysis technique at 200°C. These high-level multi-element doping results in significant effects on the structural, morphological, optical properties of pure ZnO thin film. X-ray diffraction study demonstrated ZnO wurtzite phase stabilization for each deposited film. SEM micrographs revealed a noteworthy transition from original nanorod to well distributed homogeneous fine particles morphology. UV-vis spectroscopy disclosed a sharp rise in transparency (~98%) and band gap (4eV) doped films. At the end, correlations of structural and morphological parameters with tuned functional properties were demonstrated.
Abstract: Configurational disorder due to high level multi element doping has gained huge attention from research community because of its possibility of unique phase stability as well as unusual functional properties. Based on this context extensive researches performed in recent decades to establish a new horizon of materials i.e. high entropy alloy and ce...
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Nanoindentation Induced Elastic-plastic Deformation of GaN Nanomembrane on a Sapphire Substrate
Maha Khayyat,
Eric Bourhis,
Rami Elafandy,
Tienkhee Ng,
Boon Ooi
Issue:
Volume 7, Issue 1, March 2021
Pages:
15-22
Received:
4 January 2021
Accepted:
19 January 2021
Published:
28 January 2021
Abstract: One of the main challenges of the production of a blue laser is the preparation of defect-free GaN layers. It is of high tehnological interest to characterize GaN nanomembrane mechanically for further advanced applications. The current study addresses the impact of applied stresses on GaN nanomembranes, which are placed on sapphire the substrates, using nanoindentation as a nondestructive test. The mechanical response of the 20, and 100 nm thin GaN nanomembrane were studied at different normal applied loads ranging from 1 mN down to 0.1 mN using the Berkovich nanoindentation technique. There were plastic deformation regions at the nanoindented GaN nanomembranes monitored by the load-displacement (p-h) curves. The depth of the deformed regions increased with increasing the applied loads on the diamond indenter. Beside the in-situ depth estimation of the residual nanoindentation using the instrumented nanoindentation machine, Atomic Force Microscopy (AFM) has been deployed as an ex-situ measurements of indentations depth. Scanning Electron Microscopy (SEM) provided us with surface images of the indented membranes. Indentation of the 100 nm thick GaN nanomembrane, where the effect of the substrate is reduced, showed discontinuity in the p-h curves. These discontinuity or pop-in events were attributed to a possible sudden initiation and propagation of threading dislocations in the GaN nanomembrane which was free of threading dislocation upon fabrication. It was suggested to employ μ-Raman spectroscopy methods to investigate the possible structural phase transformation of thicker GaN nanomembranes and to measure the compressive or tensile stresses within the center of the indented zones. Where the observed sudden load-displacements discontinuity or depth excursions during indentation of GaN nanomembranes can be attributed.
Abstract: One of the main challenges of the production of a blue laser is the preparation of defect-free GaN layers. It is of high tehnological interest to characterize GaN nanomembrane mechanically for further advanced applications. The current study addresses the impact of applied stresses on GaN nanomembranes, which are placed on sapphire the substrates, ...
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Obtained Carbon Nano-onions from Underwater Arc Discharge Without the Complex Purification Procedures
Salih Mohamed Osman,
Asma Mohamed Elhussein,
Fatma Osman Mahmoud,
Mohammed Bilal Sabahelkher,
Lorenzo Caputi,
Andrea Scarcello,
Francesca Alessandro
Issue:
Volume 7, Issue 1, March 2021
Pages:
23-27
Received:
12 January 2021
Accepted:
3 February 2021
Published:
23 February 2021
Abstract: Carbon nano-onions (CNOs), which consist of concentric graphitic shells, currently attract much attention because of their unique structural and physical properties, which are different from the properties of the other carbon nanomaterials such as fullerenes, graphene, and carbon nanotubes (CNTs). Due to their small size, the large external surface area and high conductivity, CNOs are used for supercapacitor applications. The arc discharge underwater is an effective and simple method for the synthesis of larger CNOs in reasonable quantities. In this research, we have been obtained carbon nanomaterials using arc discharge in water between two high purity graphite electrodes. The main experimental techniques used to characterize carbon nanostructures have been Transmission Electron Microscopy (TEM) and Raman Spectroscopy. Among them, Raman spectroscopy is the most useful non-destructive technique capable of differentiating between these various structures. Our TEM images showed that the samples collected from the material floating on the water surface consist CNOs with other carbon nanomaterials such as CNTs. We observed for the first time the formation of solid agglomerate on the cathode surface. Raman and TEM results revealed that the agglomerate is made exclusively of CNOs. The defragmentation of such agglomerate allows to obtain CNOs free of other carbon nanomaterials without the complex purification procedures needed for floating nanomaterials.
Abstract: Carbon nano-onions (CNOs), which consist of concentric graphitic shells, currently attract much attention because of their unique structural and physical properties, which are different from the properties of the other carbon nanomaterials such as fullerenes, graphene, and carbon nanotubes (CNTs). Due to their small size, the large external surface...
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Optical Band Energy, Urbach Energy and Associated Band Tails of Nano Crystalline TiO2 Films at Different Annealing Rates
Geoffrey Gitonga Riungu,
Simon Waweru Mugo,
James Mbiyu Ngaruiya,
Gitonga Mbae John,
Nelson Mugambi
Issue:
Volume 7, Issue 1, March 2021
Pages:
28-34
Received:
24 January 2021
Accepted:
25 February 2021
Published:
9 March 2021
Abstract: Increase in world population has led to more energy demand. Therefore, there is need for utilization of green and renewable energy. Dye sensitized solar cells (DSSCs) based on TiO2 have attracted a lot of attention as an alternative source as compared to current silicon technology. In this study, TiO2 thin films were deposited on doped fluorine tin oxide layer (FTO) glass substrates using sol-gel doctor blading technique. The films were annealed at different rates (1step, 2°C/min and 1°C/min) up to a temperature of 450°C followed by sintering at this temperature for 30 minutes. UV-VIS spectrophotometry was employed to probe the absorbance and reflectance of the films. It was found that, the optical parameters, such as the reflectance, the real (ε1) and imaginary (ε2) parts of dielectric constant, skin depth, Urbach energy and the energy gap; all depend on the annealing rate. The skin depth for the samples in visible region were found to increase from 6.319 x 10-5 to 11.968 x 10-5 cm-1 due to annealing. The Optical band energy (Eg) decreased from 5.04eV for as deposited film to 4.35eV at annealing rate of 1°C/min for direct allowed and from 2.76 to 2.56 eV for indirect transitions. Urbach tails in weak absorption region decreased with annealing rate. Urbach energies (Eu) were in the range of 432-505 meV for as deposited and annealed films. This was used to account for the disorder of the films. An inverse relation between Urbach energy and optical band energy as result of annealing rate was reported.
Abstract: Increase in world population has led to more energy demand. Therefore, there is need for utilization of green and renewable energy. Dye sensitized solar cells (DSSCs) based on TiO2 have attracted a lot of attention as an alternative source as compared to current silicon technology. In this study, TiO2 thin films were deposited on doped fluorine tin...
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