Photocatalytic and UV-VIS Optical Properties of Titanium-Silver Doped Composite Synthesized by Hydrothermal Method

Titanium (TiO2) has been studied and proved to be the most ideal photocatalyst due to several aspects such as high photoactivity, thermal and chemical stability, relatively inexpensive and non-toxicity. As the problem statement, the photoactivity and optical stability are the crucial aspects to synthesize an ideal photocatalyst. These aspects can be improved through the synthesize method to enhance its nanocrystal crystallinity. The purpose of this research is to synthesize the high crystalline silver-titanium (AgTiO2) nanoparticles and study its photoactivity and optical properties. The Ag-TiO2 was synthesized through the modification of caustic hydrothermal method and molten salt doping process to dope the silver nitrate (AgNO3) as a dopant agent. The photoactivity performance of high grade TiO2 and high crystallinity Ag-TiO2 were examine via a Methylene Blue Degradation (MBD) testing under both visible light and UV light. The optical properties were measured through the Surface Area BET (SBET) and UV-Vis-NIR spectrophotometer (UV-Vis). The UV-Vis results show that the 0.01%-Ag-TiO2 sample has a lowest band gap with 2.6eV compared to the commercial TiO2 (P25) and other samples. The SBET analysation shows that, the biggest surface area was formed in 0.05%-Ag-TiO2 followed by 0.01%-Ag-TiO2, un-doped TiO2 and 0.03%-Ag-TiO2. For the MBD-testing, the high crystalline Ag-TiO2 was performed a better photoactivity compared to the high grade TiO2. The 0.05%-Ag-TiO2 has the best crystallinity and morphology growth compared to 0.01%-Ag-TiO2 and 0.03%-Ag-TiO2 doping samples. The results obtained proves that, the presence of silver dopants was successfully improved the nanocrystal crystallinity of Ag-TiO2 and influenced its photoactivity performance.

Enhancement of Acoustic Performance of Oil Palm Frond Natural Fibers by Substitution of Jute Fiber

Noise is defined as an unpleasant or loud sound, which may cause disturbance to others. It can damage an inner ear and even cause noise-induced hearing loss, threatening health and well-being. Researchers have successfully studied and invented many different types, shapes, and sizes of sound absorbers to absorb/control unwanted noises. A simple method used to control noise is by controlling the noise source using acoustic absorption panels, reducing noise along the transmission path, and protecting the noise at the receiving end before it reaches the receiver. Presently, the market or in most developed countries uses synthetic materials for buildings to absorb sound. The commonly used synthetic materials are glass or mineral fibers as they can be produced chemically in the factory very quickly. However, materials such as foam, rock wool, and glass wool made from minerals are recognized for their poisonous and polluting effects, which are harmful to human health and the environment. This paper reported the effect of substitution of Jute on the acoustic performance of Oil Palm Frond (OPF) natural fibers (150 kg/m3) with a thickness of 19 mm. Jute is suitable for insulating, antistatic, and low thermal conductivity. It also has a promising result of sound absorption coefficient (SAC) at lower frequency range (50 - 1000 Hz), and on the contrary for OPF, the SAC is only promising at higher frequency range (2000 Hz - 6400 Hz). Thus, it will be very remarkable to study these two blending fibers' acoustic performance. The findings show the substitution of Jute to broaden the frequency range of SAC above 0.8. For 20 % of jute substitution, SAC's frequency range above 0.8 is 1600 – 6400 Hz. Whereas for both 40 % and 60 % of jute substitution, the frequency range is marginally widened to 1400 – 6400 Hz. For 80 % of jute substitution, the frequency range of SAC above 0.8 has been increased to 1000 – 6400 Hz. An impressive result has been observed, where 100 % OPF unable to reach the SAC of 0.9 throughout the frequency range of 0 – 6400 Hz. Jute has proved its ability to improve its acoustic performance at a more comprehensive frequency range.

Impact of Laser Intensities at Various DPI and Pixel Time on the Properties of Denim Garments

This paper investigates the changes in the properties of denim garments with respect to laser intensities of different DPI and Pixel Time. The laser added value to denim garments can fade the outer surface and the yarn portion significantly. In this research, DPI 20 and 25 along with Pixel Time 100, 150 and 200 were applied on samples to investigate the fabric weight, absorbency, crease recovery, tear resistance, tensile strength, pilling and abrasion resistance. For each of the cases, increased DPI and Pixel Time had much greater impact than other parameters on the denim garment samples. After treatment, the fabric sample indicated around 10-30% in weight reduction. The absorbency property of the sample on the other hand showed that higher DPI and Pixel Time required less time to absorb the water on the fabric surface. Furthermore, fabric crease recovery property reduced sharply where maximum 33% crease could not recover after laser exposure. For both tear resistance and tensile strength, especially warp way direction, property reduced more compared to weft way direction due to higher fading effects. After 12,000 cycles, both pilling and abrasion resistance property demonstrated significant reduction for higher laser intensities.

Concrete Brick Properties Incorporating EPS and POFA as Replacement Materials

The implementation of sustainable construction and green building becomes the main attention of construction industries in Malaysia as it has been introduced by the government in the Construction Industry Transformation Programme (2016-2020). Therefore, this study focuses on the development of sustainable concrete bricks containing Expanded Polystyrene (EPS) and Palm Oil Fuel Ash (POFA) as sand and cement substitute materials. The percentage of replacement is 20%, 30%, 40% and 50% for EPS and 5%, 10%, 15%, 20% and 25% for POFA. There are 30 different mix designs of brick have been produced and their properties have been identified. Hardened brick density, compressive strength, water absorption and initial rate of absorption are the brick properties identified in this study. Based on the experimental results, it was found that the hardened brick density and compressive strength of the brick decreased as the replacement percentage increased. On the other hand, the water absorption and initial rate of absorption of the brick decreased as the percentage of EPS increased and increased as the percentage of POFA increased. Based on the findings, it shows that EPS and POFA has significantly contributes to the reduction of brick density. Next, for the compressive strength all the bricks have satisfied the minimum strength requirement of non-load bearing brick. Finally, for water absorption and initial rate of absorption, it has been found that majority of the bricks have an acceptable value based on standard requirements for brick. This can be concluded that EPS and POFA could be potential substitute materials for the manufacture of sustainable bricks.

The Effect of Temperature on Catalytic Pyrolysis of HDPE Over Ni/Ce/Al2O3

The main objective of the current work is to investigate the influence of reaction temperature on catalytic pyrolysis of High-Density Polyurethane (HDPE) over Ni/Ce/Al2O3 into enriched hydrocarbons of pyrolytic oil and gas The experiments were performed at four different pyrolysis reaction temperatures (500, 600, 700, and 800 °C) via in-situ fixed bed reactor. The Al2O3 (75 wt.%) was used as a support, while nickel (20 wt.%) and cerium (5 wt.%) were impregnated as promoters via incipient wetness impregnation method. The catalyst to plastic mass ratio was kept constant at 1:1 for all investigated samples. The results revealed that the Ni/Ce/Al2O3 catalyst has synergistic effects on the catalytic pyrolysis of HDPE into a high yield of hydrocarbon compounds (C5 – C20) in pyrolytic oil and hydrogen gas composition in pyrolytic gas. The highest yield of pyrolytic oil was achieved at 700 °C (53.23 %), while the highest yield of pyrolytic gas was achieved at 800 °C (67.85 %). The small molecular hydrocarbons in pyrolytic oil (C5 - C9) decreases with increasing temperature from 500 to 800 °C. The highest hydrogen gas yield of 77.59 %. was achieved at 700 °C. Thus, this research has economic feasibility in producing alternative valuable energy from the plastic waste stream.

Advances in Antifouling Strategies in Membrane Ultrafiltration: A Brief Review

This study briefly reviews the recent advances in membrane and separation technology for antifouling strategies for membrane ultrafiltration. Membrane fouling is inevitable in ultrafiltration due to the eventual membrane pore blockage with foulants. Consequently, flux declines and affects the membrane integrity over time along with elevation in processing time and thereby complicating the overall membrane maintenance. To combat this issue, several studies had been undertaken such as grafting of TiO2 nanotubes (TNTs), graphene oxide nanosheets, zwitterions or polymers in the membrane and also by applying direct current. Moreover, many researchers emphasized on the integration of an enhanced pre-treatment process such as adsorption, coagulation, electrocoagulation and so on. By critically analysing and comparing the existing studies, the impact, suitability, efficiency and sustainability of the antifouling strategies will be discussed in this review. This refined approach of observing the progress in membrane technology will enable the determination of the existing gaps in the studies and will help to expand and propel the field further in separation efficiency.

Optimization of Cutting Tool Geometry for Milling Operation using Composite Material – A Review

Fibre reinforced composite materials having their own specific advantages are why they currently gain more and more attention. A vital procedure once preparations of materials are done is the machining process. Various secondary operations such as milling, drilling, turning and various unconventional processes are used for achieving near net shape and size of desired component. Compared to conventional materials, fibre reinforced composite materials are more practical to be use in machining process due to less amount of cutting forces are required to complete the exact shape and size of desired component. Therefore, a review on milling of fibre reinforced composite material will be helpful for numerous researchers and other manufacturing industries, which are currently working in this field. This review paper represents the classification of composite materials, Fiber Reinforced Plastic (FRP) Composites and Carbon Fibre Reinforced Plastic (CFRP) Composites. In addition, this review also defines the machinability of CFRP composites selection and tool design of end mill.

Graphene-Silver Based Passive Q-Switcher

Pulsed fiber laser has gain massive attention among researchers. As one of the recognized methods in generating pulsed lasers, passive Q-switching technique in 1.5 micrometer region was used in this work. A graphene-silver composite (Gr-Ag) was integrated as the saturable absorber (SA) in this work. For ease of integration, a free-standing SA film was fabricated by using chitin as the host polymer. The pulsed fiber laser was generated within the input pump power of 135.7 mW to 181.5 mW. Distinct trends of repetition rate and pulse width was observed where the former shows an increasing trend and vice versa for the latter. At 181.5 mW, pulsed laser with repetition rate and pulse width at 59.97 kHz and 2.74 µs, respectively were recorded while the pulse energy and instantaneous peak power were at 5.64 nJ and 1.93 mW, respectively. The findings from this work have shown Gr-Ag SA as a suitable candidate in Q-switched pulsed laser generation.

Preparation and Properties of Magnetic Iron Oxide Nanoparticles for Biomedical Applications: A Brief Review

Magnetic Iron oxide in nanostructure form with multifunctional properties may play a vital role in myriad biomedical applications. Iron oxide nanoparticles (IONPs) are fabricated via various methods, including thermal decomposition, co-precipitation, polyol, bio-mineralization, and green synthesis processes. Therefore, different researchers produced IONPs via various techniques to show better water permeability, antioxidant activity, biocompatibility, biodegradability, and lower or no toxicity, as advantages compared to commercial magnetic agents used in innovative applications for modern societies. This review explains various fabrication methods of IONPs and their multifunctional properties. Overall, the new advanced approaches, issues and main challenges, surface modification and modern applications of IONPs are considered. Lastly, some future developments and the views in these research areas are also discussed.

A Review on Stability and Heat Transfer Performance of Nanofluid Using Surfactants

Nanofluid had been widely used in heat transfer applications due to its better thermophysical properties. However, nanofluid had a problem in the stability of nanoparticles suspended in the based fluid. Several ways had been done to increase the stability of nanofluids including using surfactants. The purpose of this review is to uncover the stability and heat transfer performance of nanofluid using surfactants. A systematic review was used to collect the related articles for this review. This review shows the mechanism of two types of surfactants that had been used which are ionic and non-ionic. Furthermore, the stability of nanofluid is very important to enhance the thermal performance of nanofluid. The recommendations are highlighted to study the optimum amount of surfactant for respective nanofluids.