International Journal of Nanoelectronics and Materials (IJNeaM)

Fabrication and Characterization of Dome-Shaped Actuator Membrane for Peristaltic Valveless Electromagnetic Micropump

Ayub Subandi — 2024-10-01

This paper discusses the method of fabrication and characterization of a peristaltic micropump with a dome-shaped electromagnetic (EM) actuator membrane by pouring Polydimethylsiloxane (PDMS) on top of the glass master mould. The peristaltic micropumps have three membranes separated by a spacer of 2 mm. The structure of the mould consists of three pillar-shaped glasses that have a dome-like structure at the top. The border on the edge of the mould functions as a barrier to prevent the spill of the PDMS. When the PDMS is poured on top of the glass mould, a thin membrane will be formed and it will automatically overflow to form a chamber and spacer. The fabricated membrane structures were characterized using Scanning Electron Microscopy (SEM), while the mechanical and electrica properties were analysed by observing the deformation of the membrane. The SEM images show that a hanging PDMS membrane with a thickness of 77.5 µm was established. The permanent magnet connected to the lever and attached to the membrane will interact with the magnetic field generated by the EM coil. The measurement results show that a coil of 275 turns carrying a current of 600 mA produces a magnetic field of 11 mT causing a membrane deflection of 1.5 mm. The resulting dome-shaped membrane will have its potential application for the use as the actuator for the EM peristaltic micropumps.

Physical Properties of Nanostructured Zinc Sulfide Thin Films Deposited by the PLD Method for Gas Sensing

Suad M. Kadhim — 2024-10-01

The pulsed laser deposition (PLD) technique created nanostructured semiconducting zinc sulfide (ZnS) thin films onto a quartz substrate. A gas sensing static unit, field emission scanning electron microscopy (FE-SEM), and X-ray diffraction (XRD) were used to analyze the structural, surface morphology, and gas sensing properties of the as-deposited thin films. After the ZnS thin films were formed, they were heated to evaluate the effects of annealing on the characteristics of the ZnS film. XRD analysis reveals that the ZnS thin films exhibit a structure similar to zinc blend cubes, with a preference for the (111) orientation. The X-ray diffraction (XRD) patterns that emerge during annealing show that ZnS thin films become more crystalline. Grain size increases as the annealing temperature rises. Images captured by field emission scanning electron microscopy (FESEM) revealed a grain-like sphere for each of the annealed thin films, confirming the growth of grains. The UV-Vis spectra showed that the ZnS samples' transmittance boosts after annealing because their crystalline quality is improved. The transmittance is measured within the 400 ̶ 900 nm band, and the optical band gap is direct at 3.72 eV, decreasing to 3.51 eV at 350 °C during annealing. Annealing significantly improves the physical properties of ZnS thin films, according to all presented data. NO₂ and CO₂ gas were used to obtain the I-V values of the samples. The ability of ZnS thin films formed at different annealing temperatures was tested using NO₂ gas. The sensors were fabricated and tested at different operating temperatures and NO₂ gas concentrations of 100, 300, 400, 500, and 700 ppm.

Silicon Nanowire Biosensors for Diabetes Mellitus Monitoring

M. Shaifullah A. S — 2024-10-02

The main goal of this research is the development of a label-free biosensor for the detection of diabetes mellitus (DM) using the target molecule retinol-binding protein 4 (RBP4). The enzyme-linked immunosorbent assay (ELISA) approach, currently used to detect DM, is time-consuming and difficult. As a result, label-free biosensors are being considered as an alternative. In this research, silicon nanowires (SiNWs) were selected as the transducer for this biosensor due to their low cost, real-time analysis capability, high sensitivity, and low detection limit. The SiNWs were created using conventional lithography, reactive ion etching (RIE), and physical vapor deposition (PVD), and then dripped with a gold nanoparticle solution to create gold-decorated SiNWs. The surface of the gold-decorated SiNWs was functionalized using 3-aminothiophenol and glutaraldehyde solutions before being immobilized with DM RBP4 antibodies and targets. The electrical characterization of the gold nanoparticle decorated SiNWs biosensor revealed good performance in DM detection. The pH tests confirmed that the SiNWs acted as a transducer, with current proportional to the DM RBP4 concentration. The estimated limit of detection (LOD) and sensitivity for detecting DM RBP4 binding were 0.076 fg/mL and 8.92 nA(g/mL)^-1, respectively. This gold nanoparticle decorated SiNWs biosensor performed better than other methods and enabled efficient, accurate, and direct detection of DM. The SiNWs could be used as a distinctive electrical protein biosensor for biological diagnostic purposes. In conclusion, gold nanoparticle deposition offers effective label-free, direct, and high-accuracy DM detection, outperforming previous approaches. Thus, these SiNWs serve as novel electrical protein biosensors for future biological diagnostic applications.

Effect of magnetic field on the structural, optical, and electrical properties of CdS nanoparticles in distilled water by using pulsed laser ablation

Yamamah K. Abdalaah — 2024-10-02

In this study, we investigated the impact that the incorporation of a magnetic field has on the properties of cadmium sulfide CdS nanoparticles as well as the performance of an n-CdS/p-Si heterojunction photodetector that was developed by the use of the pulsed laser ablation in a liquid method. Nd:YAG laser pulses (1.064 μm, 550 mJ) were utilized to ablate cadmium sulfide CdS nanoparticles in water. The synthesized nanoparticles were shown to have a polycrystalline hexagonal structure, as evidenced by the findings of the X-ray diffraction experiment, the crystallite size for cadmium sulfide CdS decreased from 4.611 nm to 4.518 nm. The lattice constants of cadmium sulfide CdS nanostructures were determined to be a = 4.1302, c = 6.702, and c/a=1.622. The strain and dislocation density of cadmium sulfide CdS exhibited an increase. Images taken from a field emission scanning electron microscope demonstrated the formation of spherical nanoparticles on the surface. A magnetic field was applied, increasing the CdS film's crystallinity. As a consequence of this enhancement, the particle size of the CdS decreased from 25.18 nm to 12.17 nm. A comparison was made between this and the size of the crystallites that appeared when no magnetic field was present. The EDS spectrum of magnetically prepared cadmium sulfide CdS films indicates the presence of Cd and S, and the weight percentage ratios [Cd]/[S], increase from 3.72 to 3.80. The transmission electron microscopy (TEM) pictures of CdS samples that were generated using a magnetic field contained particles of small size with a mean of 10.10 nanometers. From the FT-IR spectra of cadmium sulfide CdS prepared using a magnetic field within 400–4000 cm−1, the peaks (bands) of cadmium sulfide CdS at 617 cm⁻¹ represent the bending vibration of Cd-S. As a result of the influence of a magnetic field, the optical energy gap of CdS nanoparticles increased from 2.30 eV to 2.72 eV, as indicated by the UV-Vis study. From PL emission spectra the values of the energy band gap of cadmium sulfide CdS increased from 2.45 eV at 505.7 to 2.47 eV when a magnetic field was applied. CdS NP films produced under the influence of a magnetic field were identified as having n-type characteristics by Hall effect assessments, Particle mobility was influenced by particle size. The effect of applying a magnetic field on the efficiency of the n-CdS/p-Si photodetector was investigated and analyzed. When a magnetic field was applied during ablation, the responsivity of n-CdS/p-Si heterojunction photodetectors increased from 0.498 A/W to 0.830 A/W at 510 nm. This was the result of the application of the magnetic field.

Hexagonal Enhanced Porous GaN with Delayed Integrated Pulse Electrochemical (iPEC) Etching

Nurul Syuhadah Mohd Razali — 2024-10-02

This present study investigates the effect of time delay (Td) on the formation of porous GaN (P-GaN) using integrated pulse electrochemical (iPEC) etching. Porous GaN (P-GaN) was formed by etching an N-type GaN wafer with a 4% KOH electrolyte for 60 minutes under an ultraviolet (UV) lamp at a current density of 80 mA/cm2. A Td of 120 minutes was applied before electrochemically etching the P-GaN sample. The top view image of the field emission scanning electron microscopy (FESEM) revealed a significant difference when a Td was applied. A dense and uniform hexagonal P-GaN was obtained from the Td iPEC sample, while the non-Td sample exhibited a multi-layered hexagonal porous structure with unfinished pore-etched areas. Higher porosity and deeper pores were observed in the Td sample. Intense high-resolution X-ray diffraction (HR-XRD) peak intensity was observed in the Td iPEC sample with a lower full width half maximum (FWHM), indicating that the sample had better crystallinity. The Raman spectra of the sample anodized with a Td exhibited higher Raman peak intensity and a slight shift to a higher frequency concerning as-grown GaN, indicating better crystallinity and a tensile stress relaxation of 0.24 GPa. Post etching, a blue shift of the photoluminescence (PL) peak, from 364 nm (as-grown GaN) to 363 nm (P-GaN), was observed, and a small PL peak started to form around 385 nm compared to the as-grown GaN due to the relaxation of the tensile stress, which modified the bandgap. The PL peak intensity of the Td sample was higher than the non-Td sample, indicating that the porosity and uniformity allowed more light interaction with the material, resulting in more efficient photon absorption and emission. The results indicated that potentially efficient optoelectronics devices can be fabricated on a P-GaN using a combination of electroless and electrochemical etching of the GaN epitaxial layer.

Sustainable production of graphene oxide with ascorbic acid reduction: characterization and insights

Thaddeus Lee — 2024-11-05

In this study, graphene oxide (GO) was synthesized from graphite powder using KMnO₄ and a concentrated mixture of H₂SO₄/H₃PO₄. The obtained GO was subsequently reduced using ascorbic acid. The ratios of H₂SO₄ to H₃PO₄ and KMnO₄ to graphite powder were kept constant. The synthesized GO and reduced graphene oxide (rGO) were evaluated using UV-visible spectroscopy, FT-IR spectroscopy, XRD, SEM, and EDX. The findings showed that processing graphite powder with KMnO₄ at 60 °C for 12 hours resulted in a high degree of oxidation and minimal defects. Furthermore, ascorbic acid, an alternative to highly toxic hydrazine, aided in eliminating oxygen-containing functional groups in the rGO. This study focuses on the properties of GO produced using the improved Hummer's method, and the changes observed after chemical reduction.

A Comparative Study of Microwave Welding Using Multiwalled Carbon Nanotubes and Silicon Carbide Nanowhiskers as Microwave Susceptors

Phey Yee Foong — 2024-10-02

Recently, microwave welding has arisen as an advanced joining method due to its versatility and rapid heating capabilities. Among others, microwave susceptors play a crucial role in microwave welding, as different classes of microwave susceptors have distinct microwave heating mechanisms. In this work, polypropylene (PP) was utilized as a thermoplastic substrate and two types of microwaves susceptors, namely multiwalled carbon nanotubes (MWCNTs) and silicon carbide nanowhiskers (SiC NWs), were studied for microwave welding. The susceptor was first dispersed in acetone to form susceptor suspension. Next, the susceptor suspension was deposited onto the targeted area on substrate and paired with another bare PP substrate. The paired sample was then exposed to 800 W microwave radiation in a microwave oven. Afterward, the welded joint was evaluated using a tensile test and scanning electron microscopy to determine its joint strength and cross-section microstructure. The results showed that the joint strength increased as the heating duration increased. The welded joint formed using MWCNTs achieved a maximum strength of 2.26 MPa when 10 s was used, while the SiC NWs-formed welded joint achieved a maximum strength of 2.25 MPa at 15 s. This difference in duration in forming a complete welded joint can be attributed to the higher microwave heating rates and thermal conductivity of MWCNTs. However, increasing the heating duration to 20 s caused severe deformation at the welded joint and resulted in low joint strength. Overall, this study highlights the significance of understanding the microwave heating mechanism of different susceptors and provides essential insight into the selection of a microwave susceptor for microwave welding.

Smart self-assembled polymeric-MMT/Moringa Oleifera L. particles by solvent replacement method

Rahimah Othman — 2024-10-02

Obesity, stemming from metabolic syndrome and energy imbalance, is a common health concern characterized by excess energy consumption and fat buildup. Moringa Oleifera L. (MO), known for its anti-obesity properties, is extracted via Soxhlet extraction. MO is extracted using the Soxhlet extraction method. To evaluate the antioxidant properties of MO powder, several analyses were conducted, including the assessment of total phenolic content (TPC), total flavonoid content (TFC), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) activity, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) activity. The TPC and TFC, DPPH activity, and ABTS activity values were determined to be 386.7 mg GAE/g and 82.33 mg QE/g, 32.86 %, and 49.4 % respectively. To improve drug delivery, the freeze-dried MO powder was encapsulated within a polymeric carrier, poly(e-caprolactone) (PCL). Moreover, the incorporation of montmorillonite (MMT) into the MO-loaded PCL nanoparticles enhanced the encapsulation efficiency and drug loading of MO. Nanoprecipitation was employed as a method to produce the nanoparticles, and the effects of four key parameters were studied: the ratio of aqueous phase volume to organic volume (1.5 – 10), stirring speed (400 rpm – 1200 rpm), mass weightage of MO (1 % -5 %), and mass weightage of MMT (2 % - 5 %). Design Expert was utilized for full factorial analysis to assess the impact of these parameters on encapsulation efficiency and drug loading. The optimal formulation was achieved at the ratio of aqueous phase volume to the organic volume of 1.5, stirring speed of 400 rpm, mass weightage of MO at 1 %, and mass weightage of MMT at 5% The expected encapsulation efficiency is 91.33 % and drug loading is 6.49 %.

Taguchi Method Statistical Analysis on Characterization and Optimization of 18-nm Double Gate MOSFETs

A.H Afifah Maheran — 2024-10-03

A bi-layer graphene with a multigate structure was intensified and analysed on an 18-nm Metal Oxide Semiconductor Field-Effect Transistor (MOSFET) device to obtain an optimal performance parameter. The device has a gate structure made of Titanium Dioxide (TiO2) that serves as a high-k material and a metal gate made of Tungsten Silicide (WSix). The Silvaco TCAD Software which are ATHENA and ATLAS modules were used to enhance the fabrication process of virtual devices and to verify the electrical properties of a specific device. According to the International Technology Roadmap Semiconductor (ITRS) specifications of 0.179 V ± 12.7% for threshold voltage (VTH) and 20 nA/m for leakage current (ILEAK), the Taguchi L9 orthogonal array strategy was used to improve the device process parameters for optimum VTH and ILEAK. For the NMOS device, the process parameter of VTH Adjust Implant Dose was used as the dominant factor while Source/Drain (S/D) Implant Energy was used as the adjustment factor whereby for PMOS device, S/D Implant Energy was the dominant factor while S/D Implant Tilt was the adjustment factor in order to achieve a robust design through the Taguchi method implementation. The percentage affecting the process parameter is then applied to the results of the signal to noise ratio (SNR) of Nominal-the-best (NTB) for VTH and Smaller-the-better (STB) for ILEAK.

Electronic Properties of ZnO Nanowires: A First-Principles Analysis Using Two-Probe Methodology

Rajan Vohra — 2024-10-03

In this study, the electrical characteristics of pure ZnO nanowires are investigated using density functional theory (DFT) inside the non-equilibrium Green's function (NEGF) paradigm. We clarify the underlying electronic behaviours by a thorough analysis of I-V curves, density of states (DOS) spectra, and transmission spectra. All calculations are carefully carried out using the Quantum Wise Atomistic Tool Kit programme and the Generalised Gradient Approximation (GGA). Our results show that localised d orbitals dominantly contribute to ZnO nanowire transmission properties. We also investigate the effect of doping with copper on these characteristics. Gradual doping from pristine to 2 and 4 Cu atoms shows significant enhancements, indicating a clear relationship between electrical properties and doping concentration. Notably, the device's potential as a resistor is highlighted by the greater linearity of current with copper doping, demonstrating adherence to Ohm's law. Moving beyond basic research, we tackle real-world issues in sensing applications, including the quick identification of copper molecules in water. We provide light on the Au-ZnO-Au structure's potential for sensor applications by thoroughly discussing its electron transport properties. In conclusion, this study advances our knowledge of the electrical characteristics of ZnO nanowires and how doping modifies them, opening the door to their application in a variety of electronic and sensing devices.

Investigating the Effect of Steel Wire and Carbon Black from Worn Out Tyre on the Strength of Concrete

Norlia Mohamad Ibrahim — 2024-10-03

Technology in concrete is rapidly developing to improve the quality and properties of concrete. One of the many recycled materials is worn-out tyres. Currently, the use of tires is very widespread considering the use of vehicles that increase from time to time. Piles of discarded tires can cause a lot of damage to the environment. So, by using steel wire waste (SWW) as new fiber reinforcement in concrete and with the combination with carbon black (CB), it is hoped that, by doing this, not only it could improve the quality of concrete, but also preserves the environment. Therefore, the objective of this research was, to identify the properties of fresh concrete with the addition of SWW and CB, and also to investigate the physical and mechanical properties of hardened concrete, incorporating of SWW as additional fiber reinforcement and CB. For fresh concrete, workability using a slump test was conducted. Several tests were carried out on the properties of hardened concrete. Among them were compressive strength, flexural strength, splitting tensile strength, and water absorption. The physical appearance of the concrete has also been examined and recorded. There are four batches of concrete which consist of one control batch and three batches of concrete with various weights of SWW which are in the portion of 300 g, 600 g, and 900 g, and the weight of CB is maintained at 300 g for all batches. For workability, all concrete batches with the addition of SWW and CB show acceptable workability. For the case of the density of fresh concrete, samples containing 900 g addition of SWW have the highest density which was 2520 kg/m³, as expected. Results for water absorption show that the lowest value is contributed by the control sample which was 7.6%. For compressive and flexural strength, 300 g addition of SWW has the highest value which was 28.52 MPa for compressive strength and 7.52 MPa for flexural strength. Lastly, for splitting tensile strength, the highest value was also obtained when 300 g addition of SW was added which was 5.4 MPa. To conclude, SWW and CB can be added to concrete to obtain comparable strength of concrete. However, some modifications could be made to both recycle materials to improve concrete performance.

Enhancing mechanical properties of 2024-Aluminium Alloy Matrix Composite strengthened by Y2O3 ceramic particles

Mhmood Salim Hassoon — 2024-10-07

The development of high-strength, low-weight composite materials has been a high-priority demand in the structural, aerospace, automotive, renewable energy, and sports equipment sectors. Micro-particle size Yttrium oxide (Y2O3) has been utilized to enhance the microstructure and mechanical characteristics of the 2024-Al alloy. The stir-casting technique is employed to prepare 2024-Al alloy and aluminum matrix composites (AMCs) with different Y2O3 weight fractions (1 %, 2 %, and 3 %). Scanning electron microscope ESM with EDS analysis and optical microscope imaging have been used to assess the development in the microstructure of AMCs. Furthermore, optical microscope images have been analyzed by using image processing software, ImageJ to evaluate development in microstructure grain size. Vickers' micro-hardness, tensile strength, elongation, and wear-resistant tests were conducted to assess the mechanical properties of AMCs. AMC image analysis results demonstrated a significant reduction in microstructure grain size. The highest reduction in grain size was recorded when adding 2 wt. % of Y2O3, which was approximately 22.5 % smaller than that of the plain alloy. Other mechanical test results demonstrated an increase in the hardness and tensile strength of AMCs compared with the plain alloy by approximately 58 % and 116 %, respectively, upon the addition of 2 wt. % of Y2O3, also tensile test shows increasing of AMCs elongation at failure point with increasing Y2O3 content, 132 % upon adding 3 wt. %. Finally, wear tests show a decrease in the AMC wear rate with an increasing Y2O3 weight fraction compared to the plain alloy.

Turning waste into strength: Enhancing geopolymer composites with Oil Palm Frond Fibers (OPF)

Ng Hui-Teng — 2024-10-07

Geopolymers are alternatives to ordinary Portland cement as construction materials. The increasing demand for sustainable construction materials has driven the utilization of industrial by-products and agricultural waste. The disposal of oil palm frond (OPF) biomass as waste in landfills poses significant environmental challenges, necessitating effective recycling strategies. This study examines the incorporation and feasibility of OPF as a reinforcing fiber in fly ash geopolymer composites, examining its impact on physical and mechanical properties. Various parameters were tested, including fiber content (10–20 wt.%), shapes (shredded and tubular), and lengths (1–3 cm). The geopolymer composites with 10 wt.% shredded oil palm frond and 1-cm tubular oil palm frond fibers enhance the compressive strength by 17% compared to the control sample without oil palm frond. The shredded oil palm frond was particularly effective, enhancing strength performance and achieving better dispersion within the geopolymer matrix. Conversely, increasing the fiber content and length generally resulted in diminished composite strength, attributed to the creation of a more porous structure and weaker fiber-matrix interactions. However, lower fiber additions were shown to decrease porosity and water absorption, highlighting the potential of optimized oil palm frond fiber content and form in improving the environmental and mechanical performance of geopolymer composites. These results support the viability of oil palm frond as a sustainable additive in geopolymers, contributing to waste reduction and material innovation in construction.

Formation of Gold Bone Nanorods shape using copper as foreign metal ion

Suratun Nafisah — 2024-10-08

In this study, copper (Cu) is introduced as a foreign metal ion replacing platinum by modifying the recipe of GNBPs and the final structure obtained is gold bone nanorods (GBNRs). The aspect ratio and surface density of GBNRs were investigated by varying the growth time during the growth process from 30 minutes to 5 hours. It was found that the growth solution has been changed from colourless to light blue and violet colour with increasing growth time, indicating the formation of GBNRs. The UV-Vis analysis shows two resonance plasmon peaks for t-SPR and l-SPR at 583 nm and 766 nm with the intensity of 1.433 a.u and 2.236 a.u at the optimum 5 hours growth time. For morphological analysis, it was found that the sample with lower growth time produced gold nanosphere shapes and with increasing time, more GBNRs with large aspect ratios were produced. HR-TEM characterization reveals that bone nanorods are formed due to the influence of Cu foreign metal ions, which cause selective deposition of Au atoms onto {111} facet of gold nanorods, while simultaneously reducing the overgrowth rate of the {110} facet for the edge regions and the {100} facet for the tip regions of the nanorods. In addition, the influence of Cu foreign metal ions on the growth mechanism of Au nanoseeds into nanorods and the shape transformation of nanorods into bone nanorods are also discussed in this work. In conclusion, the GBNRs have been successfully synthesized using SMGM by induced Cu as foreign metal ions.

2-Axis controlled spray pyrolysis deposition device for Dye-sensitized Solar Cell (DSSC)

Siti Nurhaziqah Abd Majid — 2024-10-08

Dye-sensitized solar cells (DSSCs) are a promising alternative to traditional silicon-based photovoltaic systems due to their efficient light-to-electricity conversion. A critical component of DSSCs is titanium dioxide (TiO₂), responsible for converting light into electrical energy. Spray pyrolysis was one of the methods for fabricating TiO₂ thin films. However, there are several drawbacks, such as challenges in particle size control, maintaining homogeneity of the thin film, and scalability issues during the deposition process. Modifications to the manufacturing process are necessary to achieve optimal performance in DSSCs, particularly with the thickness of the cell. This work focuses on the 2-axis spray pyrolysis process, a cost-effective way to create thin and thick films. In particular, it focuses on TiO₂ thin films utilized as working electrodes in DSSC applications. The method was performed at different motor speeds, namely MS80, MS100, and MS120. The X-ray diffraction (XRD) spectrum showed that the dominance of the anatase phase appeared in an MS100. The UV-Vis results depict that the band gap value is 3.02 eV. The surface profiler analysis indicates that sample MS100 has an optimal thickness of 15.17 µm. The DSSC achieved 9.4% efficiency with sample MS100. This finding demonstrates that using
2-axis controlled spray pyrolysis deposition improves DSSC performance with an optimal motor speed.

Polysulfone (Psf) Mixed Matrix Membrane incorporating Titanium Dioxide (TiO2)/Polyethylene Glycol (PEG) for the removal of copper

Vasuumathi A/P Ilango Mathialagan — 2024-10-08

The global increasing contamination of water resources with toxic metals such as copper (Cu), poses severe threats to human health and aqueous ecosystems. Therefore, the ultrafiltration mixed matrix membranes (UF MMMs) possess an applicable approach for the removal of copper ions. This novel fabricated technology can be applied in various wastewater treatment systems for the removal of heavy metals, especially copper. MMMs were fabricated by blending polysulfone (Psf) with additives into the dope solution via the phase inversion method by incorporating titanium dioxide (TiO₂) and polyethylene glycol (PEG) in Psf MMMs. Seven Psf MMMs samples labelled M0 to M6, each with its own formulation, were prepared and tested for density, porosity, and degree of Cu retention. MMMs were further characterized via Fourier transform infrared spectroscopy (FTIR), which revealed the range of the IR spectrum of Psf polymer membrane from 1319 cm^-1 to 1600 cm^-1, 1650 cm^-1 to 3400 cm^-1 for PEG, and 800 cm^-1 to 3600 cm^-1 for TiO₂ NPs. As for the scanning electron microscopy (SEM), M6 (Psf/TiO₂/PEG 6000) was found to be the most dense and highest porous morphology asymmetric Psf MMM. The retained percentage of Cu and flux for M6 attained the highest value of 80.3% and 136.99 L/m² .h respectively, whereas for the neat Psf membrane, M0 exhibited the lowest retained percentage of Cu and flux, about 25.8% and 61.64 L/m².h. The inclusion of pore former and additives has shown an improvement of 54.5% in the copper rejection. Moreover, M6 displayed the highest antifouling properties compared to other Psf MMMSs. This study proves that PEG and TiO₂ additives have significant potential to improve membrane performance due to the highest percentage of Cu retained on the surface of the membrane as adsorptive separation on Psf MMMs.

Bonding strength of steel and concrete containing Palm Oil Fuel Ash (POFA) and Expanded Polystyrene (EPS)

Mohamad Hairi Osman — 2024-10-08

The usage of recycled materials in concrete has become popular recently. This paper focuses on a study related to the bonding between steel and concrete containing expanded polystyrene beads (EPS) and palm oil fuel ash (POFA) as replacement material. The EPS were used as fine aggregate replacement, and POFA was used as cement replacement. The replacement percentages for EPS and POFA in the concrete were limited to a range of 0-30% and 0-10%, respectively. Previous studies have identified the potential of POFA and EPS as concrete substances. The typical issue with EPS-containing concrete is its characteristic weakness, which leads to a compromised bond with steel. This occurs because EPS fails to effectively interact with cement, resulting in a weak bond and low compressive strength. Consequently, in this study, POFA is introduced as an addition to enhance the bond strength between EPS-containing concrete and steel. Pull-out tests in this study seem to represent the bonding performance between concrete and steel. The 10% of POFA in concrete seems might improve its performance in terms of compression strength, and bonding between concrete and steel.

Drying Shrinkage Properties and Engineering Performance for Cement Mortar Containing Bamboo Biochar Powder (BCP)

Noor Ain Najihah Che Rosely — 2024-10-17

Drying shrinkage, the reduction in volume as a material like cement mortar dries, can result in cracks and decreased durability. Bamboo biochar powder (BCP) serves as a substitute for cement in mortar, affecting its drying shrinkage characteristics. Research has shown that BCP in cement mortar can alleviate drying shrinkage by absorbing and retaining moisture. This study aims to assess the chemical and physical properties of BCP, determine the mechanical attributes of bamboo biochar mortar with varying percentages of cement replacement, and investigate the impact of BCP on mortar shrinkage in indoor and outdoor tropical conditions. BCP, derived from Gigantocholoa Abociliata species and sized at 75 µm, was used to replace cement rates of 0%, 5%, 10%, 15%, and 20%. Sixty cube samples (50x50x50mm) were employed for density, ultrasonic pulse velocity (upv), compressive strength, and water absorption tests. Additionally, thirty prism samples (100x100x400mm) were employed to assess drying shrinkage during outdoor and indoor exposure, spanning up to 150 days. The experimental data indicates a consistent trend as the percentage of cement replacement increases in the mortar mix, density, and compressive strength decrease, while UPV and water absorption increase. The lowest shrinkage strain was observed during indoor exposure with 5% cement replacement, attributed to BCP acting as a filler, creating strong bonding properties, and reducing shrinkage. Conversely, the highest strain was noted during outdoor exposure with 20% cement replacement, resulting from higher moisture loss. In summary, a 5% replacement of cement with BCP in mortar offers the most effective reduction in shrinkage strain.

Synthesis and Characterization of TiO2 -CQDs Nanocomposites and Testing of Their Anticancer Potential

Maryam S. Jabbar — 2024-10-22

This work used a green approach to produce carbon quantum dots (CQDs). TiO2 nanoparticles (NPs) and TiO2–CQDs nanocomposites with different weight ratios of CQDs were organized through a facile sol-gel method. XRD showed that the anatase and rutile phases of TiO2 were polycrystalline with a tetragonal structure and that the CQDs exhibited a broad peak at (002) and a hexagonal structure. High resolution-transmission-electron microscopy revealed that the TiO2 NPs agglomerated in mostly spherical shapes and that the anatase and rutile phases of TiO2 had sizes of less than 15 and 25 nm, respectively. The CQDs had a relatively uniform diameter, a spherical shape with a highly crystalline structure, and a size below 2 nm. UV–visible spectroscopy revealed that the absorbance of the TiO2- CQDs nanocomposites increased with the increase in CQD ratio. The energy band gaps of the anatase and rutile phases were 3.07 and 2.7 eV, respectively, whereas that of CQDs was 3.14 eV. Meanwhile, the energy band gaps of the TiO2–CQDs nanocomposites decreased with the increase in CQDs ratio. The growth inhibition rates of the liver cancer HepG2 cell line and the normal cell line RD were measured after 24 hours of experience to the two TiO2 phases and TiO2–CQDs nanocomposites. The cytotoxicity test presented that the tested substances were extremely harmful to cells in cancer. Inhibition rates increased with the increase in CQDs ratio. The inhibition rate of growth in cancer cells, including the liver cancer HepG2 cell line and the normal cell line (RD), was measured for 24 hours after they were exposed to TiO2 (two phases) and TiO2-CQDs nanocomposites. The samples showed a slight effect on the normal line (RD) compared to HepG2 cancer. The highest inhibition rate was 12.11% for the CQD 0.7 sample.

Synthesis of Gold Nanoparticles by Pulsed Laser Ablation and its Study Physical and Mechanical Properties

Ahmed Hamza Ahmed — 2024-11-05

In this work, the pulsed laser ablation technique was used, which is considered a good and distinctive method. Gold nanoparticles (AuNP) were prepared using an Nd-YAG laser with specific parameters, wavelength 1064 nm, constant ablation energy 1000 mJ, frequency 1 Hz, and different number of pulses (300, 600, and 900 pulse/sec). Deionized water was used as the medium liquid. The purpose of this study was to examine the change in these parameters on AuNP using a variety of Xrd, FESEM, Uv-Vis, force-hardness, and compression measurements. The pure cubic crystal structure of gold nanoparticles was analyzed using XRD. Subsequent FESEM images (average diameters 78.07nm, 49.15nm, 37.67nm) indicate that the particles had highly spherical and quasi-spherical shapes. Using ultraviolet analysis, the absorption band of gold nanoparticles was found and the wavelength was (518, 519, 524) nanometers, respectively. There were three different power gaps (1.895, 2.005, and 2.084) eV. In addition, mechanical property tests were conducted, where 2 ml of gold nanoparticles were mixed with (3 grams) of traditional dental filling. The hardness value increased by (3%). The results also showed an increase in the stress and strain value and an increase in Young’s modulus. Hence, an increase in the compressive strength. This indicates that AuNP affects the mechanical properties and enhances their effectiveness.