Showing 3 results for Hameed
M. Mahdi, A. Abdul-Hameed, B. Ali, H.f Al-Taay,
Volume 17, Issue 1 (March 2020)
Abstract
Silicon nanowires (SiNWs) are synthesized through a metal-assisted chemical etching (MACE) method using Si(100) substrates and silver (Ag) as a catalyst. Scanning electron microscope (SEM) images confirmed that length of prepared SiNWs was increased when etching time increased. The prepared SiNWs demonstrated considerably low light reflectance at a wavelength range of 200–1100 nm. The photoluminescence (PL) spectra of the grown SiNWs showed a broad emission band peaked at a wavelength of about 750 nm. A solar cell and photodetector based on heterojunction SiNWs/PEDOT:PSS were fabricated using SiNWs that prepared with different etching time and its J–V, sensitivity, and time response were investigated. The conversion efficiency of fabricated solar cell was increased from 0.39% to 0.68% when wire length decreased from 24 µm to 21 µm, respectively. However, the sensitivity of the heterojunction SiNWs/PEDOT:PSS photodetector was decreased from 53774% to 36826% when wire length decreased from 24 µm to 21 µm, respectively.
Sibbt Jabbar, Dalya Hameed, Imad Disher,
Volume 23, Issue 2 (June 2026 2026)
Abstract
Geopolymer/nano carbon black composite is a promising electrically conductive smart material that can be used in self-heating and self-sensing applications. This paper studies the effect of adding nano carbon black to the physical, mechanical, electrical, and electrothermal performance of metakaolin-based geopolymer. Carbon black was added at the percent of 5%, 10%, 15%, and 20% by weight of metakaolin; the compressive strength was tested at various ages of 7, 14, 28, and 90 days, and the electrothermal performance was tested using AC and DC voltages. The results showed that a compromise between suitable compressive strength and high electrothermal conversion could be achieved when a specific balance between the carbon black percent and the lowest water content is established. A composite with a compressive strength of 27 MPa and stable electrothermal performance reaching 142°C at 9V DC can be prepared using 20 wt% of carbon black and a water-to-metakaolin ratio of 0.549, which is used as a smart material in construction applications.
Hawra H. Obeed, Ali Mejbel M. Alkhafaji, Layth Hayder Hameed Kazem Al_tmamimi, Tabarek Falah Deindee, Mohammed Ridha Shaeed Janabi,
Volume 23, Issue 2 (June 2026 2026)
Abstract
Researchers have increasingly investigated hybrid nanocomposites that mix physical and chemical properties of carbonaceous materials and metal/metal oxides. In this work, a nanocomposite composed of reduced graphene oxide and silver (I) oxide, rGO@Ag2O, was prepared using ascorbic acid as a green reducing agent. The Ag2O nanoparticles were synthesized by means of a controlled precipitation process in water. The carbonaceous material of rGO was obtained through a modified Hummers' approach. After being combined with a solvent, the Ag2O and rGO in ethanol were dried with heat. The resultant nanocomposite was structurally and optically examined using different characterization techniques.
The results showed that GO has been successfully reduced, Ag2O revealed a crystalline structure, and Ag₂O nanostructures were found on the surface of rGO sheets. Disk diffusion assay was adopted in order to evaluate antibacterial activity of nanocomposite against both Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) bacteria. The Ag₂O nanostructures in the composite form exhibited inhibition zone with higher diameter compared to their uncomposited counterparts. Higher antibacterial activity of rGO@Ag2O was attributed to the role of negatively charged oxygen-containing groups present on the surface of rGO in slightly improvement in the stability of Ag₂O nanostructures.
Our findings show that rGO@Ag₂O could be a useful antimicrobial material for biomedical surfaces, as a coating, and in systems that clean water. It could be a good option for future research in nano-enabled antimicrobial technology because it can destroy bacteria, is made in an environmentally benign way, and could be made on a larger scale.
