| 2. |
- Shah, Aqeel Ahmed, et al.
(author)
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Facile synthesis of copper doped ZnO nanorods for the efficient photo degradation of methylene blue and methyl orange
- 2020
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In: Ceramics International. - Oxford : Elsevier. - 0272-8842 .- 1873-3956. ; 46:8, part A, s. 9997-10005
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Journal article (peer-reviewed)abstract
- In this study, zinc oxide (ZnO) nanorods are doped with copper by low temperature aqueous chemical growth method using different concentrations of copper 5 mg, 10 mg, 15 mg and 20 mg and labeled as sample 1, 2, 3 and 4 respectively. The morphology and phase purity of nanostructures was investigated by scanning electron microscopy, and powder X-ray diffraction techniques. The optical characterization was carried out through UV–Vis spectrophotometer. The band gap of coper doped ZnO has brought reduction at 250–600 nm and it indicates the fewer time for the recombination of electron and hole pairs, thus enhanced photo degradation efficiency is found. ZnO exhibits nanorods like shape even after the doping of copper. The photo degradation efficiency for the two chronic dyes such as methyl orange MO and methylene blue MB was found to be 57.5% and 60% respectively for a time of 180 mints. This study suggests that the copper impurity in ZnO can tailor its photocatalytic activity at considerable rate. The proposed photo catalysts are promising and can be used for the waste water treatment and other environmental applications. © 2019 Elsevier Ltd and Techna Group S.r.l.
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| 3. |
- Bhatti, Muhammad Ali, et al.
(author)
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Efficient photo catalysts based on silver doped ZnO nanorods for the photo degradation of methyl orange
- 2019
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In: Ceramics International. - Oxford : Elsevier. - 0272-8842 .- 1873-3956. ; 45:17, Part B, s. 23289-23297
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Journal article (peer-reviewed)abstract
- In this study, the doped ZnO nanorods with silver (Ag) as photosensitive material are prepared by the solvothermal method. The structural and optical characterization is carried out by the scanning electron microscopy, X-ray diffraction, energy dispersive spectroscopy and UV–visible spectroscopy. The use of Ag as dopant did not alter the morphology of ZnO except sample 4 which has flower like morphology. The Ag, Zn and O are the main constituent of doped materials. The XRD revealed a hexagonal phase for ZnO and cubic phase for silver and confirmed the successful doping of Ag. The photocatalytic activity of Ag doped ZnO nanorods was investigated for the photo degradation of methyl orange. The photocatalytic measurements show that 88% degradation of methyl orange by the sample 4 within the 2 h of UV light treatment (365 nm) is significant advancement in the photocatalyst and provide the inexpensive and promising materials for the photochemical applications. © 2019 Elsevier Ltd and Techna Group S.r.l.
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| 4. |
- Waly, Mohamed Ibrahim, et al.
(author)
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Advancement of a High-Efficiency Wearable Antenna Enabling Wireless Body Area Networks
- 2023
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In: IEEE Access. - Piscataway, NJ : IEEE. - 2169-3536. ; 11, s. 138325-138335
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Journal article (peer-reviewed)abstract
- This paper presents a unique antenna that is designed to be efficient, with improved gain and partial flexibility, for use in wearable biomedical telemetry applications. The antenna design utilizes a semi-flexible RO5880 substrate material (dielectric constant, epsilon(r) = 2.2, loss tangent, ( tan delta ) = 0.0009) with physical dimensions measuring 0.47 lambda(g)x 0.47 lambda(g) . The model involves the incorporation of rectangular inverted C slots, which effectively results in a reduction of the resonant frequency. Additionally, a distributed rectangular slot is introduced on the ground plane, contributing to the augmentation of the operational bandwidth. The operational frequency of the proposed antenna design is 2.40 GHz, accompanied by a bandwidth (BW) of 320 MHz at a -10 dB level. This equates to a fractional percentage bandwidth (FBW) of 13.33% centered around the frequency of 2.40 GHz. The antenna design presented in this work demonstrates the preservation of improved gain and efficiency, achieving values of 3.67 dBi and 94%, respectively, at a frequency of 2.40 GHz. The work demonstrates through simulation and experimental outcomes that the antenna exhibits minimal impact on parameters such as gain reflection coefficient (|S-11|) , BW, and bending efficiency. Furthermore, the antenna underwent simulation and experimental testing in close proximity to the human body, revealing favorable operational characteristics. The proposed antenna exhibits substantial potential as a viable option for wearable biomedical instruments. Thus, the proposed wearable antenna design in this study offers a wideband antenna for ISM band applications, expanding bandwidth without compromising performance. Bending the antenna minimally affects gain, bandwidth, and efficiency when worn on the body, making it suitable for wearables. It also maintains a reasonably low Specific Absorption Rate (SAR), reducing wave absorption by the body. Unique features like rectangular inverted C slots and a distributed rectangular slot on the ground plane enhance bandwidth while maintaining performance during bending. © 2013 IEEE.
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