Displaying publications 61 - 80 of 509 in total

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  1. Fulltext Modeling, Optimization and Performance Evaluation of TiC/Graphite Reinforced Al 7075 Hybrid Composites Using Response Surface Methodology
    Alam MA, Ya HH, Yusuf M, Sivraj R, Mamat OB, Sapuan SM, et al.
    Materials (Basel), 2021 Aug 20;14(16).
    PMID: 34443232 DOI: 10.3390/ma14164703
    The tenacious thirst for fuel-saving and desirable physical and mechanical properties of the materials have compelled researchers to focus on a new generation of aluminum hybrid composites for automotive and aircraft applications. This work investigates the microhardness behavior and microstructural characterization of aluminum alloy (Al 7075)-titanium carbide (TiC)-graphite (Gr) hybrid composites. The hybrid composites were prepared via the powder metallurgy technique with the amounts of TiC (0, 3, 5, and 7 wt.%), reinforced to Al 7075 + 1 wt.% Gr. The microstructural characteristics were investigated by optical microscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS) elemental mapping. A Box Behnken design (BBD) response surface methodology (RSM) approach was utilized for modeling and optimization of density and microhardness independent parameters and to develop an empirical model of density and microhardness in terms of process variables. Effects of independent parameters on the responses have been evaluated by analysis of variance (ANOVA). The density and microhardness of the Al 7075-TiC-Gr hybrid composites are found to be increased by increasing the weight percentage of TiC particles. The optimal conditions for obtaining the highest density and microhardness are estimated to be 6.79 wt.% TiC at temperature 626.13 °C and compaction pressure of 300 Mpa.
  2. Fulltext A Double-Negative Metamaterial-Inspired Mobile Wireless Antenna for Electromagnetic Absorption Reduction
    Alam T, Faruque MRI, Islam MT
    Materials (Basel), 2015 Jul 29;8(8):4817-4828.
    PMID: 28793474 DOI: 10.3390/ma8084817
    A double-negative metamaterial-inspired antenna is presented for mobile wireless applications. The antenna consists of a semi-circular radiating patch and a 3 × 4 hexagonal shaped metamaterial unit cell array in the ground plane. The antenna is fed with a 50 Ω microstrip feed line. The electric dimensions of the proposed antenna are 0.20λ × 0.26λ × 0.004λ, at the low-end frequency. The proposed antenna achieves a -10 dB impedance with a bandwidth of 2.29 GHz at the lower band and 1.28 GHz at the upper band and can operate for most of the mobile applications such as upper GSM bands, WiMAX, Bluetooth, and wireless local area network (WLAN) frequency bands. The focused novelties of the proposed antenna are its small size, multi-standard operating bands, and electromagnetic absorption reduction at all the operating frequencies using the double-negative metamaterial ground plane.
  3. Fulltext Strength and Acid Resistance of Ceramic-Based Self-Compacting Alkali-Activated Concrete: Optimizing and Predicting Assessment
    Algaifi HA, Khan MI, Shahidan S, Fares G, Abbas YM, Huseien GF, et al.
    Materials (Basel), 2021 Oct 19;14(20).
    PMID: 34683800 DOI: 10.3390/ma14206208
    The development of self-compacting alkali-activated concrete (SCAAC) has become a hot topic in the scientific community; however, most of the existing literature focuses on the utilization of fly ash (FA), ground blast furnace slag (GBFS), silica fume (SF), and rice husk ash (RHA) as the binder. In this study, both the experimental and theoretical assessments using response surface methodology (RSM) were taken into account to optimize and predict the optimal content of ceramic waste powder (CWP) in GBFS-based self-compacting alkali-activated concrete, thus promoting the utilization of ceramic waste in construction engineering. Based on the suggested design array from the RSM model, experimental tests were first carried out to determine the optimum CWP content to achieve reasonable compressive, tensile, and flexural strengths in the SCAAC when exposed to ambient conditions, as well as to minimize its strength loss, weight loss, and UPVL upon exposure to acid attack. Based on the results, the optimum content of CWP that satisfied both the strength and durability aspects was 31%. In particular, a reasonable reduction in the compressive strength of 16% was recorded compared to that of the control specimen (without ceramic). Meanwhile, the compressive strength loss of SCAAC when exposed to acid attack minimized to 59.17%, which was lower than that of the control specimen (74.2%). Furthermore, the developed RSM models were found to be reliable and accurate, with minimum errors (RMSE < 1.337). In addition, a strong correlation (R > 0.99, R2 < 0.99, adj. R2 < 0.98) was observed between the predicted and actual data. Moreover, the significance of the models was also proven via ANOVA, in which p-values of less than 0.001 and high F-values were recorded for all equations.
  4. Fulltext Reconfigurable Radiation Pattern of Planar Antenna Using Metamaterial for 5G Applications
    Ali Esmail B, Majid HA, Zainal Abidin Z, Haimi Dahlan S, Himdi M, Dewan R, et al.
    Materials (Basel), 2020 Jan 26;13(3).
    PMID: 31991912 DOI: 10.3390/ma13030582
    In this research, a reconfigurable metamaterial (MM) structure was designed using a millimeter-wave (MMW) band with two configurations that exhibit different refractive indices. These two MM configurations are used to guide the antenna's main beam in the desired direction in the 5th generation (5G) band of 28 GHz. The different refractive indices of the two MM configurations created phase change for the electromagnetic (EM) wave of the antenna, which deflected the main beam. A contiguous squares resonator (CSR) is proposed as an MM structure to operate at MMW band. The CSR is reconfigured using three switches to achieve two MM configurations with different refractive indices. The simulation results of the proposed antenna loaded by MM unit cells demonstrate that the radiation beam is deflected by angles of +30° and -27° in the E-plane, depending on the arrangement of the two MM configurations on the antenna substrate. Furthermore, these deflections are accompanied by gain enhancements of 1.9 dB (26.7%) and 1.5 dB (22.4%) for the positive and negative deflections, respectively. The reflection coefficients of the MM antenna are kept below -10 dB for both deflection angles at 28 GHz. The MM antennas are manufactured and measured to validate the simulated results.
  5. Fulltext Investigating Optimal Confinement Behaviour of Low-Strength Concrete through Quantitative and Analytical Approaches
    Ali M, Abbas S, Salah B, Akhter J, Saleem W, Haruna S, et al.
    Materials (Basel), 2021 Aug 19;14(16).
    PMID: 34443196 DOI: 10.3390/ma14164675
    Reinforced concrete is used worldwide in the construction industry. In past eras, extensive research has been conducted and has clearly shown the performance of stress-strain behaviour and ductility design for high-, standard-, and normal-strength concrete (NSC) in axial compression. Limited research has been conducted on the experimental and analytical investigation of low-strength concrete (LSC) confinement behaviour under axial compression and relative ductility. Meanwhile, analytical equations are not investigated experimentally for the confinement behaviour of LSC by transverse reinforcement. The current study experimentally investigates the concrete confinement behaviour under axial compression and relative ductility of NSC and LSC using volumetric transverse reinforcement (VTR), and comparison with several analytical models such as Mander, Kent, and Park, and Saatcioglu. In this study, a total of 44 reinforced-column specimens at a length of 18 in with a cross-section of 7 in × 7 in were used for uniaxial monotonic loading of NSC and LSC. Three columns of each set were confined with 2 in, 4 in, 6 in, and 8 in c/c lateral ties spacing. The experimental results show that the central concrete stresses are significantly affected by decreasing the spacing between the transverse steel. In the case of the LSC, the core stresses are double the central stress of NSC. However, increasing the VTR, the capacity and the ductility of NSC and LSC increases. Reducing the spacing between the ties from 8 in to 2 in center to center can affect the concrete column's strength by 60% in LSC, but 25% in the NSC. The VTR and the spacing between the ties greatly affected the LSC compared to NSC. It was found that the relative ductility of the confined column samples was almost twice that of the unrestrained column samples. Regarding different models, the Manders model best represents the performance before the ultimate strength, whereas Kent and Park represents post-peak behaviour.
  6. Fulltext Synthesis, Surface Nitriding and Characterization of Ti-Nb Modified 316L Stainless Steel Alloy Using Powder Metallurgy
    Ali S, Irfan M, Muhammad Niazi U, Rani AMA, Shah I, Legutko S, et al.
    Materials (Basel), 2021 Jun 13;14(12).
    PMID: 34199244 DOI: 10.3390/ma14123270
    The powder metallurgy (PM) technique has been widely used for producing different alloy compositions by the addition of suitable reinforcements. PM is also capable of producing desireable mechanical and physical properties of the material by varying process parameters. This research investigates the addition of titanium and niobium in a 316L stainless steel matrix for potential use in the biomedical field. The increase of sintering dwell time resulted in simultaneous sintering and surface nitriding of compositions, using nitrogen as the sintering atmosphere. The developed alloy compositions were characterized using OM, FESEM, XRD and XPS techniques for quantification of the surface nitride layer and the nitrogen absorbed during sintering. The corrosion resistance and cytotoxicity assessments of the developed compositions were carried out in artificial saliva solution and human oral fibroblast cell culture, respectively. The results indicated that the nitride layer produced during sintering increased the corrosion resistance of the alloy and the developed compositions are non-cytotoxic. This newly developed alloy composition and processing technique is expected to provide a low-cost solution to implant manufacturing.
  7. Fulltext Amino Anthraquinone: Synthesis, Characterization, and Its Application as an Active Material in Environmental Sensors
    Ali S, Tahir M, Mehboob N, Wahab F, J Langford S, Mohd Said S, et al.
    Materials (Basel), 2020 Feb 21;13(4).
    PMID: 32098037 DOI: 10.3390/ma13040960
    This work reports synthesis, thin film characterizations, and study of an organic semiconductor 2-aminoanthraquinone (AAq) for humidity and temperature sensing applications. The morphological and phase studies of AAq thin films are carried out by scanning electron microscope (SEM), atomic force microscope (AFM), and X-ray diffraction (XRD) analysis. To study the sensing properties of AAq, a surface type Au/AAq/Au sensor is fabricated by thermally depositing a 60 nm layer of AAq at a pressure of ~10-5 mbar on a pre-patterned gold (Au) electrodes with inter-electrode gap of 45 µm. To measure sensing capability of the Au/AAq/Au device, the variations in its capacitance and resistance are studied as a function of humidity and temperature. The Au/AAq/Au device measures and exhibits a linear change in capacitance and resistance when relative humidity (%RH) and temperature are varied. The AAq is a hydrophobic material which makes it one of the best candidates to be used as an active material in humidity sensors; on the other hand, its high melting point (575 K) is another appealing property that enables it for its potential applications in temperature sensors.
  8. Fulltext Inflammatory Responses in Oro-Maxillofacial Region Expanded Using Anisotropic Hydrogel Tissue Expander
    Ali Salim KM, Abd Jalil A, Radzi Z, Ismail SM, Czernuszka JT, Rahman MT
    Materials (Basel), 2020 Oct 06;13(19).
    PMID: 33036128 DOI: 10.3390/ma13194436
    OBJECTIVE: Reconstruction of oral and facial defects often necessitate replacement of missing soft tissue. The purpose of tissue expanders is to grow healthy supplementary tissue under a controlled force. This study investigates the inflammatory responses associated with the force generated from the use of anisotropic hydrogel tissue expanders.

    METHODS: Sprague Dawley rats (n = 7, body weight = 300 g ± 50 g) were grouped randomly into two groups-control (n = 3) and expanded (n = 4). Anisotropic hydrogel tissue expanders were inserted into the frontal maxillofacial region of the rats in the expanded group. The rats were sacrificed, and skin samples were harvested, fixed in formalin, and embedded in paraffin wax for histological investigation. Hematoxylin and eosin staining was performed to detect histological changes between the two groups and to investigate the inflammatory response in the expanded samples. Three inflammatory markers, namely interleukin (IL)-1α, IL-6, and tumor necrosis factor-α (TNF-α), were analyzed by immunohistochemistry.

    RESULT: IL-1-α expression was only observed in the expanded tissue samples compared to the controls. In contrast, there was no significant difference in IL-6, and TNF-α production. Histological analysis showed the absence of inflammatory response in expanded tissues, and a negative non-significant correlation (Spearman's correlation coefficient) between IL-1-α immune-positive cells and the inflammatory cells (r = -0.500). In conclusion, tissues that are expanded and stabilized using an anisotropic self-inflating hydrogel tissue expander might be useful for tissue replacement and engraftment as the expanded tissue does not show any sign of inflammatory responses. Detection of IL-1-α in the expanded tissues warrants further investigation for its involvement without any visible inflammatory response.

  9. Fulltext Polymer Thermal Treatment Production of Cerium Doped Willemite Nanoparticles: An Analysis of Structure, Energy Band Gap and Luminescence Properties
    Alibe IM, Matori KA, Zaid MHM, Nasir S, Alibe AM, Khiri MZA
    Materials (Basel), 2021 Feb 27;14(5).
    PMID: 33673655 DOI: 10.3390/ma14051118
    The contemporary market needs for enhanced solid-state lighting devices has led to an increased demand for the production of willemite based phosphors using low-cost techniques. In this study, Ce3+ doped willemite nanoparticles were fabricated using polymer thermal treatment method. The special effects of the calcination temperatures and the dopant concentration on the structural and optical properties of the material were thoroughly studied. The XRD analysis of the samples treated at 900 °C revealed the development and or materialization of the willemite phase. The increase in the dopant concentration causes an expansion of the lattice owing to the replacement of larger Ce3+ ions for smaller Zn2+ ions. Based on the FESEM and TEM micrographs, the nanoparticles size increases with the increase in the cerium ions. The mean particles sizes were estimated to be 23.61 nm at 1 mol% to 34.02 nm at 5 mol% of the cerium dopant. The optical band gap energy of the doped samples formed at 900 °C decreased precisely by 0.21 eV (i.e., 5.21 to 5.00 eV). The PL analysis of the doped samples exhibits a strong emission at 400 nm which is ascribed to the transition of an electron from localized Ce2f state to the valence band of O2p. The energy level of the Ce3+ ions affects the willemite crystal lattice, thus causing a decrease in the intensity of the green emission at 530 nm and the blue emission at 485 nm. The wide optical band gap energy of the willemite produced is expected to pave the way for exciting innovations in solid-state lighting applications.
  10. Fulltext Solid-State Limited Nucleation of NiSi/SiC Core-Shell Nanowires by Hot-Wire Chemical Vapor Deposition
    Alizadeh M, Binti Hamzan N, Ooi PC, Bin Omar MF, Dee CF, Goh BT
    Materials (Basel), 2019 Feb 24;12(4).
    PMID: 30813502 DOI: 10.3390/ma12040674
    This work demonstrated a growth of well-aligned NiSi/SiC core-shell nanowires by a one-step process of hot-wire chemical vapor deposition on Ni-coated crystal silicon substrates at different thicknesses. The NiSi nanoparticles (60 to 207 nm) acted as nano-templates to initially inducing the growth of these core-shell nanowires. These core-shell nanowires were structured by single crystalline NiSi and amorphous SiC as the cores and shells of the nanowires, respectively. It is proposed that the precipitation of the NiSi/SiC are followed according to the nucleation limited silicide reaction and the surface-migration respectively for these core-shell nanowires. The electrical performance of the grown NiSi/SiC core-shell nanowires was characterized by the conducting AFM and it is found that the measured conductivities of the nanowires were higher than the reported works that might be enhanced by SiC shell layer on NiSi nanowires. The high conductivity of NiSi/SiC core-shell nanowires could potentially improve the electrical performance of the nanowires-based devices for harsh environment applications such as field effect transistors, field emitters, space sensors, and electrochemical devices.
  11. Fulltext Palladium/Graphene Oxide Nanocomposite for Hydrogen Gas Sensing Applications Based on Tapered Optical Fiber
    Alkhabet MM, Yaseen ZM, Eldirderi MMA, Khedher KM, Jawad AH, Girei SH, et al.
    Materials (Basel), 2022 Nov 17;15(22).
    PMID: 36431654 DOI: 10.3390/ma15228167
    Gaseous pollutants such as hydrogen gas (H2) are emitted in daily human activities. They have been massively studied owing to their high explosivity and widespread usage in many domains. The current research is designed to analyse optical fiber-based H2 gas sensors by incorporating palladium/graphene oxide (Pd/GO) nanocomposite coating as sensing layers. The fabricated multimode silica fiber (MMF) sensors were used as a transducing platform. The tapering process is essential to improve the sensitivity to the environment through the interaction of the evanescent field over the area of the tapered surface area. Several characterization methods including FESEM, EDX, AFM, and XRD were adopted to examine the structure properties of the materials and achieve more understandable facts about their functional performance of the optical sensor. Characterisation results demonstrated structures with a higher surface for analyte gas reaction to the optical sensor performance. Results indicated an observed increment in the Pd/GO nanocomposite-based sensor responses subjected to the H2 concentrations increased from 0.125% to 2.00%. The achieved sensitivities were 33.22/vol% with a response time of 48 s and recovery time of 7 min. The developed optical fiber sensors achieved excellent selectivity and stability toward H2 gas upon exposure to other gases such as ammonia and methane.
  12. Fulltext Distinct Optical and Structural (Nanoyarn and Nanomat-like Structure) Characteristics of Zinc Oxide Nanofilm Derived by Using Salvia officinalis Leaves Extract Made without and with PEO Polymer
    Alrajhi AH, Ahmed NM, Halim MM, Altowyan AS, Azmi MN, Almessiere MA
    Materials (Basel), 2023 Jun 21;16(13).
    PMID: 37444824 DOI: 10.3390/ma16134510
    This paper reports the optical properties of zinc oxide nanofilm fabricated by using organic natural products from Salvia officinalis leaves (SOL) extract and discusses the effect of the nanocrystal (NC) structure (nanoyarn and nanomat-like structure) on nanofilm optical properties. The surface-active layer of the nanofilm of ZnO nanoparticles (ZnO NPs) was passivated with natural organic SOL leaves hydrothermally, then accumulated on zinc oxide nanorods (ZnO NRs). The nanofilms were fabricated (with and without PEO) on glass substrate (at 85 °C for 16 h) via chemical solution deposition (CSD). The samples were characterized by UV-vis, PL, FESEM, XRD, and TEM measurements. TEM micrographs confirmed the nucleation of ZnO NPs around 4 nm and the size distribution at 1.2 nm of ZnO QDs as an influence of the quantum confinement effect (QCE). The nanofilms fabricated with SOL surfactant (which works as a capping agent for ZnO NPs) represent distinct optoelectronic properties when compared to bulk ZnO. FESEM images of the nanofilms revealed nanoyarn and nanomat-like structures resembling morphologies. The XRD patterns of the samples exhibited the existence of ZnO nanocrystallites (ZnO NCs) with (100), (002), and (101) growth planes. The nanofilms fabricated represented a distinct optical property through absorption and broad emission, as the optical energy band gap reduced as the nanofilms annealed (at 120 ℃). Based on the obtained results, it was established that phytochemicals extracted from organic natural SOL leaves have a distinct influence on zoic oxide nanofilm fabrication, which may be useful for visible light spectrum trapping. The nanofilms can be used in photovoltaic solar cell applications.
  13. Wear Analysis of NiTi Sand Screens Using Altair Discrete Element Method
    Amadi AH, Mohyaldinn M, Abduljabbar A, Ridha S, Avilala P, Owolabi GT
    Materials (Basel), 2024 Jan 05;17(2).
    PMID: 38255448 DOI: 10.3390/ma17020281
    This research explores discrete element method analysis to investigate the wear of NiTi Sand Screens in comparison to traditional materials. The study utilized Altair EDEM v2022.2 software and employed Oka and Archard models to simulate the wear behavior of Nitinol, a well-established Shape Memory Alloy (SMA). The mechanical properties considered include Poisson's ratio, solid density, shear modulus, and Young modulus. Results indicate significantly higher wear values and deformations with the Oka model compared to negligible wear with the Archard model. The Oka model's emphasis on impact as the primary wear mechanism, supported by high normal cumulative energy, better represents sand screen wear phenomena. Additionally, this study indicates that factors such as particle size distribution and normal and tangential cumulative contact energy hold potential as predictors of wear response and characteristics. The Oka model demonstrated that NiTi exhibited reduced wear losses compared to SUS630 and Cr-Mn white cast iron, both of which are recognized for their high toughness when subjected to an impact load. Experimental analysis validated the simulation findings with morphological and graphical erosion plots. The limitation of observing the shape memory effect through DEM (discrete element method) simulation was acknowledged. Recommendations include characterizing post-wear microstructural changes, exploring the influence of temperature on wear behavior, and further research to refine wear models and understand SMA sand screen responses.
  14. Fulltext Optimizing of the Cementitious Composite Matrix by Addition of Steel Wool Fibers (Chopped) Based on Physical and Mechanical Analysis
    Amer AAR, Abdullah MMAB, Liew YM, A Aziz IH, Wysłocki JJ, Tahir MFM, et al.
    Materials (Basel), 2021 Feb 26;14(5).
    PMID: 33652863 DOI: 10.3390/ma14051094
    The demand for durable, resistant, and high-strength structural material has led to the use of fibers as reinforcing elements. This paper presents an investigation into the inclusion of chopped steel wool fibers (CSWFs) in cement to form a high-flexural strength cementitious composite matrix (CCM). CSWFs were used as the primary reinforcement in CCM at increments of 0.5 wt%, from 0.5-6 wt%, with ratios of cement to sand of 1:1.5 and water to cement of 0.45. The inclusion of CSWFs resulted in an excellent optimization of the physicomechanical properties of the CCM, such as its density (2.302 g/cm3), compressive strength (61.452 MPa), and maximum flexural strength (10.64 MPa), all of which exceeded the performances of other reinforcement elements reported in the literature.
  15. Multigene Expression Programming Based Forecasting the Hardened Properties of Sustainable Bagasse Ash Concrete
    Amin MN, Khan K, Aslam F, Shah MI, Javed MF, Musarat MA, et al.
    Materials (Basel), 2021 Sep 28;14(19).
    PMID: 34640055 DOI: 10.3390/ma14195659
    The application of multiphysics models and soft computing techniques is gaining enormous attention in the construction sector due to the development of various types of concrete. In this research, an improved form of supervised machine learning, i.e., multigene expression programming (MEP), has been used to propose models for the compressive strength (fc'), splitting tensile strength (fSTS), and flexural strength (fFS) of sustainable bagasse ash concrete (BAC). The training and testing of the proposed models have been accomplished by developing a reliable and comprehensive database from published literature. Concrete specimens with varying proportions of sugarcane bagasse ash (BA), as a partial replacement of cement, were prepared, and the developed models were validated by utilizing the results obtained from the tested BAC. Different statistical tests evaluated the accurateness of the models, and the results were cross-validated employing a k-fold algorithm. The modeling results achieve correlation coefficient (R) and Nash-Sutcliffe efficiency (NSE) above 0.8 each with relative root mean squared error (RRMSE) and objective function (OF) less than 10 and 0.2, respectively. The MEP model leads in providing reliable mathematical expression for the estimation of fc', fSTS and fFS of BA concrete, which can reduce the experimental workload in assessing the strength properties. The study's findings indicated that MEP-based modeling integrated with experimental testing of BA concrete and further cross-validation is effective in predicting the strength parameters of BA concrete.
  16. Fulltext Influence of Woven Glass-Fibre Prepreg Orientation on the Flexural Properties of a Sustainable Composite Honeycomb Sandwich Panel for Structural Applications
    Amir AL, Ishak MR, Yidris N, Zuhri MYM, Asyraf MRM, Zakaria SZS
    Materials (Basel), 2023 Jul 15;16(14).
    PMID: 37512295 DOI: 10.3390/ma16145021
    Owing to the high potential application need in the aerospace and structural industry for honeycomb sandwich composite, the study on the flexural behaviour of sandwich composite structure has attracted attention in recent decades. The excellent bending behaviour of sandwich composite structures is based on their facesheet (FS) and core materials. This research studied the effect of woven glass-fibre prepreg orientation on the honeycomb sandwich panel. A three-point bending flexural test was done as per ASTM C393 standard by applying a 5 kN load on different orientation angles of woven glass-fibre prepreg honeycomb sandwich panel: α = 0°, 45° and 90°. The results show that most of the sandwich panel has almost the same failure mode during the three-point bending test. Additionally, the α = 0° orientation angle shows a higher maximum load prior to the first failure occurrence compared to others due to higher flexibility but lower stiffness. In addition, the woven glass-fibre prepreg orientation angle, α = 0°, has the maximum stress and flexural modulus, which directly depend upon the maximum load value obtained during the flexural test. In addition, the experimental results and analytical prediction for honeycomb sandwich deflection show good agreement. According to the result obtained, it is revealed that woven glass-fibre honeycomb sandwich panels with an α = 0° orientation is a good alternative compared to 45° and 90°, especially when better bending application is the main purpose. The final result of this research can be applied to enhance the properties of glass-fibre-reinforced polymer composite (GFRPC) cross-arm and enhance the existing cross-arm used in high transmission towers.
  17. Plasma-Polymerised Antibacterial Coating of Ovine Tendon Collagen Type I (OTC) Crosslinked with Genipin (GNP) and Dehydrothermal-Crosslinked (DHT) as a Cutaneous Substitute for Wound Healing
    Amirrah IN, Zulkiflee I, Mohd Razip Wee MF, Masood A, Siow KS, Motta A, et al.
    Materials (Basel), 2023 Mar 29;16(7).
    PMID: 37049037 DOI: 10.3390/ma16072739
    Tissue engineering products have grown in popularity as a therapeutic approach for chronic wounds and burns. However, some drawbacks include additional steps and a lack of antibacterial capacities, both of which need to be addressed to treat wounds effectively. This study aimed to develop an acellular, ready-to-use ovine tendon collagen type I (OTC-I) bioscaffold with an antibacterial coating for the immediate treatment of skin wounds and to prevent infection post-implantation. Two types of crosslinkers, 0.1% genipin (GNP) and dehydrothermal treatment (DHT), were explored to optimise the material strength and biodegradability compared with a non-crosslinked (OTC) control. Carvone plasma polymerisation (ppCar) was conducted to deposit an antibacterial protective coating. Various parameters were performed to investigate the physicochemical properties, mechanical properties, microstructures, biodegradability, thermal stability, surface wettability, antibacterial activity and biocompatibility of the scaffolds on human skin cells between the different crosslinkers, with and without plasma polymerisation. GNP is a better crosslinker than DHT because it demonstrated better physicochemical properties (27.33 ± 5.69% vs. 43 ± 7.64% shrinkage), mechanical properties (0.15 ± 0.15 MPa vs. 0.07 ± 0.08 MPa), swelling (2453 ± 419.2% vs. 1535 ± 392.9%), biodegradation (0.06 ± 0.06 mg/h vs. 0.15 ± 0.16 mg/h), microstructure and biocompatibility. Similarly, its ppCar counterpart, GNPppCar, presents promising results as a biomaterial with enhanced antibacterial properties. Plasma-polymerised carvone on a crosslinked collagen scaffold could also support human skin cell proliferation and viability while preventing infection. Thus, GNPppCar has potential for the rapid treatment of healing wounds.
  18. Fulltext MWCNTs-TiO2 Incorporated-Mg Composites to Improve the Mechanical, Corrosion and Biological Characteristics for Use in Biomedical Fields
    Amirzade-Iranaq MT, Omidi M, Bakhsheshi-Rad HR, Saberi A, Abazari S, Teymouri N, et al.
    Materials (Basel), 2023 Feb 25;16(5).
    PMID: 36903033 DOI: 10.3390/ma16051919
    This study attempts to synthesize MgZn/TiO2-MWCNTs composites with varying TiO2-MWCNT concentrations using mechanical alloying and a semi-powder metallurgy process coupled with spark plasma sintering. It also aims to investigate the mechanical, corrosion, and antibacterial properties of these composites. When compared to the MgZn composite, the microhardness and compressive strength of the MgZn/TiO2-MWCNTs composites were enhanced to 79 HV and 269 MPa, respectively. The results of cell culture and viability experiments revealed that incorporating TiO2-MWCNTs increased osteoblast proliferation and attachment and enhanced the biocompatibility of the TiO2-MWCNTs nanocomposite. It was observed that the corrosion resistance of the Mg-based composite was improved and the corrosion rate was reduced to about 2.1 mm/y with the addition of 10 wt% TiO2-1 wt% MWCNTs. In vitro testing for up to 14 days revealed a reduced degradation rate following the incorporation of TiO2-MWCNTs reinforcement into a MgZn matrix alloy. Antibacterial evaluations revealed that the composite had antibacterial activity, with an inhibition zone of 3.7 mm against Staphylococcus aureus. The MgZn/TiO2-MWCNTs composite structure has great potential for use in orthopedic fracture fixation devices.
  19. Fulltext Mechanism of Fatigue Crack Growth in Biomedical Alloy Ti-27Nb
    Amjad M, Badshah S, Rafique AF, Adil Khattak M, Khan RU, Abdullah Harasani WI
    Materials (Basel), 2020 May 16;13(10).
    PMID: 32429420 DOI: 10.3390/ma13102299
    Implants are widely used in the human body for the replacement of affected bones. Fatigue failure is one of the serious concerns for implants. Therefore, understanding of the underlying mechanism leading to fatigue failure is important for the longevity of biomaterial implants. In this paper, the fracture toughness and fatigue crack growth of titanium alloy biomaterial Ti-27Nb has been experimentally investigated. The Ti-27Nb material is tested for fatigue crack growth in different environmental conditions representing the ambient and in vitro environments for 504 hours and 816 hours, respectively. Fractography of the tested specimen is conducted using Scanning Electron Microscope (SEM). The results of the fatigue crack growth propagation of the ambient and in vitro samples are similar in the Paris crack growth region. However, in the threshold region, the crack growth rate is higher for the Simulated Body Fluid (SBF) treated specimen. The fracture surface morphology of in vitro samples shows brittle fracture as compared to ambient specimens with significant plasticity and striations marks. It is proposed that a similar investigation may be conducted with specimens treated in SBF for prolonged periods to further ascertain the findings of this study.
  20. Fulltext Effects of Multiple Reflow on the Formation of Primary Crystals in Sn-3.5Ag and Solder Joint Strength: Experimental and Finite Element Analysis
    Amli SFM, Salleh MAAM, Aziz MSA, Yasuda H, Nogita K, Abdullah MMAB, et al.
    Materials (Basel), 2023 Jun 13;16(12).
    PMID: 37374543 DOI: 10.3390/ma16124360
    The growth and formation of primary intermetallics formed in Sn-3.5Ag soldered on copper organic solderability preservative (Cu-OSP) and electroless nickel immersion gold (ENIG) surface finish after multiple reflows were systematically investigated. Real-time synchrotron imaging was used to investigate the microstructure, focusing on the in situ growth behavior of primary intermetallics during the solid-liquid-solid interactions. The high-speed shear test was conducted to observe the correlation of microstructure formation to the solder joint strength. Subsequently, the experimental results were correlated with the numerical Finite Element (FE) modeling using ANSYS software to investigate the effects of primary intermetallics on the reliability of solder joints. In the Sn-3.5Ag/Cu-OSP solder joint, the well-known Cu6Sn5 interfacial intermetallic compounds (IMCs) layer was observed in each reflow, where the thickness of the IMC layer increases with an increasing number of reflows due to the Cu diffusion from the substrate. Meanwhile, for the Sn-3.5Ag/ENIG solder joints, the Ni3Sn4 interfacial IMC layer was formed first, followed by the (Cu, Ni)6Sn5 IMC layer, where the formation was detected after five cycles of reflow. The results obtained from real-time imaging prove that the Ni layer from the ENIG surface finish possessed an effective barrier to suppress and control the Cu dissolution from the substrates, as there is no sizeable primary phase observed up to four cycles of reflow. Thus, this resulted in a thinner IMC layer and smaller primary intermetallics, producing a stronger solder joint for Sn-3.5Ag/ENIG even after the repeated reflow process relative to the Sn-3.5Ag/Cu-OSP joints.
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