33 research outputs found
Effect of Metallic Binder Composition on Microstructure and Hardness of (W,Ti)C Cemented Carbides
No full textNovel synthesis of CNTs-Si3N4/Cu nanocomposites: electroless deposition, powder metallurgy, spark plasma sintering, microstructure, and physical properties
No full textIntroduction Metal matrix composites reinforced with ceramic and carbon nanotubes (CNTs) are considered recently as new materials for thermal managements and heat sink applications of electronic components.Method Cu nanocomposites reinforced with CNTs and different content of Si3N4 up to 5 wt.% (CNTs-xSi3N4/Cu) are synthesized by electroless Cu deposition process. The produced (CNTs-xSi3N4/Cu) nanocomposites powder were divided into two groups of samples. The first group were consolidated by two steps of cold pressing at 600 MPa compaction pressure followed by sintered under Ar atmosphere at 850 degrees C for 90 min. However, the second group of powders are spark plasma sintered (SPS) under vacuum by simultaneously applying compaction pressure of 50 MPa at sintering temperature of 850 degrees C for one min. The microstructure and the chemical composition of the investigated CNTs and the produced CNTs-xSi3N4/Cu powders as well as the CNTs-xSi3N4/Cu sintered nanocomposites were investigated by FTIR, SEM, TEM, EDX, X-ray mapping and XRD. The sinterability of the produced CNTs-xSi3N4/Cu nanocomposites is evaluated by measuring the Archimedes' density and the coefficient of thermal expansion (CTE).Results and discussion The electroless coating process enhancing the homogeneous distribution of CNTs and Si3N4 reinforced particles in the Cu matrix by preventing the formation of the agglomerations and segregations in the Cu matrix and retaining the nanostructure. The density and the CTE of the obtained CNTs-xSi3N4/Cu nanocomposites were improved by consolidation with SPS. The CNTs-xSi3N4/Cu nanocomposites sintered by SPS process have higher relative density approaches 100 % and lower CTE of 1.8 x 10-5 degrees C-1-1.6 x 10-5 degrees C-1 than, the density of the CNTs-xSi3N4/Cu nanocomposites sintered by conventional powder metallurgy technique with relative sintered density approaches 85 % and CTE of 2.6 x 10-5 degrees C-1-1.9 x 10-5 degrees C-1. Our findings owing that; the produced CNTs-Si3N4/Cu nanocomposites are expected as suitable candidate materials for thermal managements and heat sink packaging materials of electronic components.
Novel synthesis of Al2O3 short fibers/Ti-12Mo-6Zr composites for cranial reconstruction applications: spark plasma sintering, microstructure and nanomechanical properties
No full textCeramic-Titanium matrix composites have recently attracted significant interest as a new type of biomaterials protecting the brain from external force and infections of cranial defects due to its biocompatibility and good mechanical and corrosion properties matched with the bone tissue. Spark plasma sintering (SPS) is one of powder technology techniques that can be utilised in the fabrication of final net complex and irregular shape parts used for cranial reconstruction and maxillofacial trauma by reconstruction and cranioplasty. The present work studies the effect of alumina (Al2O3) short fibers reinforcement addition on the nanomechanical properties estimated by the nanoindentation measurements of the Ti-12Mo-6Zr and its correlation with the microstructure. Al2O3 short fibers/Ti-12Mo-6Zr of different Al2O3 reinforcement short fibers content up to 5 wt.% were fabricated by Spark Plasma Sintering technique. Powders of Ti, Mo, and Zr powders were mechanically wet milled with different wt.% of Al2O3 reinforced short fibers. The mechanically mixed Al2O3 short fibers/Ti-12Mo-6Zr samples of different compositions were consolidated by SPS at 1000 oC for 5 min under vacuum and 50 Mpa compaction pressure. Optical microscopy (OM), high-resolution scanning electronic microscopy (HRSEM) conducted with Electron dispersive spectroscopy (EDAX) unite and X-Ray Diffraction (XRD) are used to evaluate the particle size and shape, surface morphology, microstructure, the chemical compositions and the phase identifications for the investigated samples. The samples were determined by the rule of mixture (ROM) as well as the Archimedes' principle. The nanomechanical properties were estimated by measuring the nanoindentation of the produced Al2O3 short fibers/Ti-12Mo-6Zr sintered samples using a Berkovich indenter with continuous stiffness measurement (CSM) method. The hardness and the Young modulus were estimated from the obtained data of the applied load-displacement in the depth curves. The obtained Al2O3 short fibers/Ti-12Mo-6Zr composites have good mechanical properties which revealed the efficiency of the sintering process by spark plasma sintering. Also, the estimated hardness and Young's modulus are increased by increasing the content of the Al2O3 reinforcement nanoparticles from 1 to 5 wt.% in the Ti-12Mo-6Zr metal matrix. Based on our findings of the nanoindentation studies; it was expected that the produced Al2O3 short fibers/Ti-12Mo-6Zr new composites have appropriate physical and mechanical properties for cranial reconstruction applications.
Critical Evaluation of Combined Cu and Fe3O4 Nanodots with Gum Arabic Nano-Hybrids Using in-vitro Model: Flow Cytometry and Cell Viability Studies
No full textSami G Almalki,1 Youssef O Al-Ghamdi,2 Faisal K Algethami,3 Walid M Daoush,3 Bahauddeen M Alrfaei,4,5 Maisa Alanazi,5 Yaser E Alqurashi,6 Mahjoub Jabli2,7 1Department of Medical Laboratory Sciences, College of Applied Medical Sciences, Majmaah University, Majmaah, 11952, Saudi Arabia; 2Department of Chemistry, College of Science Al-Zulfi, Majmaah University, Al-Majmaah, 11952, Saudi Arabia; 3Department of Chemistry, College of Science, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh, 11623, Saudi Arabia; 4King Saud Bin Abdulaziz University for Health Sciences (KSAU-HS), Ministry of National Guard - Health Affairs (MNGHA), Riyadh, 11426, Saudi Arabia; 5King Abdullah International Medical Research Center, MNGHA, Riyadh, 11426, Saudi Arabia; 6Department of Biology, College of Science Al-zulfi, Majmaah University, Al-Majmaah, 11952, Saudi Arabia; 7Textile Materials and Processes Research Unit, Tunisia National Engineering School of Monastir, University of Monastir, Monastir, 5019, TunisiaCorrespondence: Walid M Daoush, Email [email protected]: Previous studies on synthesis and cytotoxicity effect of copper (Cu) and magnetite (Fe3O4) nanodots against kidney and lung cancer cells Lines.Purpose: Investigation of the effects of Cu and Fe3O4 nanodots on the reduction in viability of lung cancer (A549) and human embryonic kidney (HEK239T) cells lines.Methods: Cu and Fe3O4 nanodots/Gum Arabic (GA) hybrids were chemically synthesized, characterized, and assessed by MTT and flow cytometry for their cytotoxicity against A549 and HEK239T cells lines.Results: Novel hybrids of Cu and Fe3O4 nanodots were effectively synthesized by chemical deposition method in combination with GA stabilizing agent. The stabilized Cu and Fe3O4 nanodots by GA have median particle size of 4.7 nm and 7 nm respectively. Furthermore, the biological activities of Cu nanodots/ GA hybrids showed a strong reduction in viability for both A549 and HEK239T cells at 50 and 100 ng/μL, owing to their small size and high surface-area-to-volume ratio compared to Fe3O4 nanoparticles. Pre-apoptosis effect of the Cu nanodots/ GA hybrid on the treated A549 cells were 40% for 0.1 ng/μL, 91.4% for 1 ng/μL, 88% for 50 ng/ μL, and 87.7% for 100 ng/μL. However, in the treated human embryonic kidney (HEK293T) cells, the pre-apoptosis was found under different concentrations conditions of 89.9% for 0.1 ng/μL, 94.2% for 1 ng/μL, 76.2% for 50 ng/μL and 70.5% for 100 ng/μL. After treatment of both A549 and HEK293T cells with 100 ng/μL of Cu nanodots/GA hybrid, many cell deaths and reformed nanoparticles crystals were observed.Conclusion: Cu nanodots/GA hybrid strongly reduce the viability of both A549 and HEK239T cells at 50 and 100 ng/μL. However, Fe3O4 nanodots/GA hybrid did not show any significant effect.Keywords: Cu nanodots, Fe3O4 nanodots, Arabic gum, lung cancer, human embryonic kidney cell
Fabrication of Carbon and Related Materials/Metal Hybrids and Composites
No full textThis Special Issue on “Fabrication of Carbon and related materials/ Metal Hybrids and Composites” presents the importance of the development of new composite and hybrid materials in different fields. It consists of 17 articles contributed by authors from different countries all over the world. The articles can be categorized into four classes. The first class of includes articles focusing on the synthesis of carbon fibers, carbon nanotubes, and graphene hybrid and composite materials. The results include the developments of the methodology and know-how of the synthesis and functionalization of the graphene surface of fibers and nanotubes and their effects on binding with the metal matrix. The second class focuses on the synthesis of new polymeric materials based on pitch/polyethylene composites and their electrical and mechanical properties, including the correlations with its microstructures. Additionally, the second class presents the results of articles, including the synthesis of new biocompatible and eco-friendly metal oxide/polymer materials with antibacterial and antimicrobial activities. The third class includes articles focused on the applications of ceramic metal oxides, such as silica and clays in the development of solar cells and in the fabrications of membranes of water treatments and desalinations. The last part of this Special Issue presents results of the articles focused on high-entropy alloys and metal matrix composites and their weldability
Fabrication of Carbon and Related Materials/Metal Hybrids and Composites
No full textThis Special Issue on “Fabrication of Carbon and related materials/ Metal Hybrids and Composites” presents the importance of the development of new composite and hybrid materials in different fields. It consists of 17 articles contributed by authors from different countries all over the world. The articles can be categorized into four classes. The first class of includes articles focusing on the synthesis of carbon fibers, carbon nanotubes, and graphene hybrid and composite materials. The results include the developments of the methodology and know-how of the synthesis and functionalization of the graphene surface of fibers and nanotubes and their effects on binding with the metal matrix. The second class focuses on the synthesis of new polymeric materials based on pitch/polyethylene composites and their electrical and mechanical properties, including the correlations with its microstructures. Additionally, the second class presents the results of articles, including the synthesis of new biocompatible and eco-friendly metal oxide/polymer materials with antibacterial and antimicrobial activities. The third class includes articles focused on the applications of ceramic metal oxides, such as silica and clays in the development of solar cells and in the fabrications of membranes of water treatments and desalinations. The last part of this Special Issue presents results of the articles focused on high-entropy alloys and metal matrix composites and their weldability
Fe3O4-Coated CNTs-Gum Arabic Nano-Hybrid Composites Exhibit Enhanced Anti-Leukemia Potency Against AML Cells via ROS-Mediated Signaling
No full textAlyaa S Abdel Halim,1 Mohamed AM Ali,2,1 Fawad Inam,3,4 Abdulrahman M Alhalwan,5 Walid M Daoush5,6 1Department of Biochemistry, Faculty of Science, Ain Shams University, Cairo, 11566, Egypt; 2Department of Biology, College of Science, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh, 11623, Kingdom of Saudi Arabia; 3Department of Engineering and Computing, School of Architecture, Computing and Engineering, University of East London, London, UK; 4Executive Principal Office, Oxford Business College, Oxford, OX1 2EP, UK; 5Department of Chemistry, College of Science, Imam Mohammad Ibn Saud Islamic University, Riyadh, 11623, Kingdom of Saudi Arabia; 6Department of Production Technology, Faculty of Technology and Education, Helwan University, Cairo, 11281, EgyptCorrespondence: Walid M Daoush, Email [email protected]: Prior studies on magnetite (Fe3O4) NPs and carbon nanotubes (CNTs) cytotoxic effects against acute myeloid leukemia (AML) are inconclusive rather than definitive.Purpose: Investigation of the effects of Gum Arabic (GA)-stabilized/destabilized Fe3O4 NPs and CNTs, alone or in combination, on AML cell proliferation.Methods: Hybrid NPs were synthesized, characterized, and assessed for their cytotoxicity against Kasumi-1, HL-60, and THP-1 in comparison to normal primary bone marrow CD34+ cells. The molecular pathways of nanostructures’ cytotoxicity were also investigated.Results: The Fe3O4 NPs were effectively synthesized and attached to the surface of the CNTs, resulting in the formation of a novel hybrid through their interaction with the GA colloidal solution in an aqueous media. Although the evaluated nanostructured nanoparticles had significant growth suppression ability against the leukemia cell lines, with IC50 values ranging from 42.437 to 189.842 μg/mL, they exhibited comparatively modest toxicity towards normal hematopoietic cells (IC50: 113.529‒162.656 μg/mL). The incorporation of Fe3O4 NPs with CNTs in a hybrid nanocomposite significantly improved their effectiveness against leukemia cells, with the extent of improvement varying depending on the specific cell type. The nanostructured particles were stabilized by GA, which enhances their ability to inhibit cell proliferation in a manner that depends on the specific cell type. Also, nanoparticles exhibit cytotoxicity due to their capacity to stimulate the production of intracellular ROS, halt the cell cycle at the G1 phase, and induce apoptosis. This is supported by the activation of p53, BAX, cytochrome C, and caspase-3, which are triggered by ROS. The nanostructures lead to an increase in the expression of genes encoding proteins related to oxidative stress (SIRT1, FOXO3, NFE2L2, and MAP3K5) and cyclin-dependent kinase inhibitors (CDKN1A and CDKN1B) in response to ROS.Conclusion: We provide an effective Fe3O4 NPs/CNTs nano-hybrid composite that induces apoptosis and has strong anti-leukemic capabilities. This hybrid nanocomposite is promising for in vivo testing and validation. Keywords: acute myeloid leukemia, anti-leukemic properties, carbon nanotubes, iron oxide nanoparticles, oxidative stress, reactive oxygen specie
Co-Precipitation and Magnetic Properties of Magnetite Nanoparticles for Potential Biomedical Applications
No full textMicrostructure, physical properties and hardness of alumina short fibres/nickel matrix composites fabricated by powder technology
No full textMicrostructure and properties of BN/Ni-Cu composites fabricated by powder technology
No full textMicrosize Powders of Ni and Cu were prepared by water atomization technique to fabricate metal matrix composites containing various percentages of nanosized boron nitride particles (1, 2, 3, 4, 5 wt. % of BN in a matrix containing (20 wt. %Ni and 80 wt. %Cu). The prepared mixtures were cold compacted under 400 MPa, and sintered for 2 h at 1000 °C in a controlled atmosphere of 3:2 N2/H2 gas mixtures. The microstructure and the chemical composition of the prepared powders as well as the consolidated composites were investigated by X-ray diffraction as well as field emission scanning electron microscope (FESEM) equipped with an energy dispersive spectrometer (EDS). The produced Cu and Ni powders have spheroid shape of size less than 100 microns, but the investigated BN has an equiaxed particle shape and particle size of ∼ 500 nm. It has been also observed that BN and Ni particles were homogeneously distributed in the Cu matrix of the present BN/Ni-Cu composites. The density, electrical resistivity, saturation magnetization and hardness of the composites were measured. It was observed that, by increasing BN content, the relative density was decreased, while the saturation magnetization, electrical resistivity and hardness were increased
