Materials Science Forum Vol. 1056

Abstract: Wood-plastic composites (WPCs) are composites that incorporate plants composed up of wood and non-wood fibres blended with thermosets or thermoplastic polymers to form a composite. Oil palm trunk (OPT) is one of the wastes produced from the oil palm industry known as oil palm biomass (OPB). The OPT was utilized to turn oil palm biomass into a value-added product. In this research, oil palm trunk/polypropylene (OPT/PP) blends composite was produced by extrusion and injection molding techniques. Alkaline treatment was applied to the fibers to improve the interfacial adhesion of fibers. After alkaline treatment, treated OPT (T-OPT) and untreated (UT-OPT) together with PP were blended at 200°C with the speed of 85 rpm in the extruder to form a pellet. Pellets were then injected in injection molding at 200°C to form sample size for mechanical testing; tensile and impact testing. The physical testing conducted was Melt Flow Index (MFI), water absorption test and Thermogravimetric Analysis (TGA). The results show that the mechanical properties of OPT/PP composite were improved by alkaline treatment. In the water absorption test, T-OPT composite demonstrated lower water absorption than that of UT-OPT composite. This indicated that the reduction of water absorption in T-OPT composite is due to alkaline treatment that degraded the lignin and cellulose structure subsequently reducing the OH groups in fibers to absorb water. For TGA, T-OPT composite had slightly higher thermal stability as compared to UT-OPT composite.

Abstract: Although rigid foam core structures have gotten a lot of attention, there have only been a few researches on foam reinforced sandwich panels with aluminum alloy A6061 sheets as face-sheets. In this research, the sandwich concept was applied to develop lightweight panels for roofing system. Analysis on the influences of core thickness, density, and foam layer arrangement on energy absorption, bending strength and displacement of sandwich panel under the quasi-static three-point bending test were investigated. Sandwich panel core is made of closed-cell polyurethane foam with densities of 40 kg/m³, 60 kg/m³, and 80 kg/m³. The quasi-static three-point bending tests were conducted in accordance to ASTM C-393 Standard and the polyurethane foam cores are design accordingly to the guideline of National Institutes of Standards and Technology (NIST). Load–displacement curves and mechanical properties are shown using data from experimental works. Results demonstrate that increased in thickness of the sandwich panel, also increased the bending strength, energy absorption and displacement. Furthermore, the sandwich panel with 50 mm thickness and 60 kg/m³ density foam core has the maximum bending strength.

Abstract: The use of PLA as a green substitute for conventional plastics has increased considerably as a result of increased awareness of the environmental effect of the use of petroleum-based plastics. However, some of the PLA properties including brittleness and sensitivity to high temperature and humidity, greatly restrict its application. The addition of reinforcement of low-cost natural fibres and foaming are considered to overcome the above disadvantages since it can improve some of PLA’s processing. This paper reported the effects of supercritical carbon dioxide (SCCO₂) on the tensile strength of PLA biocomposite films produced via solution casting method. The biocomposite films underwent supercritical carbon dioxide (SCCO₂) treatment at temperature of 40°C and pressure at 200 bar. The tensile strength showed that the PLA biocomposite foamed has improved by 16.18%. This is due to a good adhesion interfacial between fiber and polymer matrix. A simulation on tensile strength of the biocomposite foamed was also conducted using COMSOL Multiphysics software. The tensile strength resulted from this simulation is similar to the experimental value. Therefore, the experimental value is valid and satisfy. This also showed that SCCO₂ treatment significantly improved the properties of PLA biocomposite films which could be an alternative in packaging industries.

Abstract: The fluorescence protein technologies have made remarkable contributions to the advancement of life science. Accordingly, the physicochemical properties of fluorescence proteins have been deeply investigated in the bulk solution that mimics the cellular environment, but those at the less common environment such as surface and interface have not been deeply investigated. We recently found the phenomenon that the fluorescence protein immobilized at the metal-solution interface exhibits voltage-dependent photoluminescence. Upon the blue light photoexcitation of Venus, a yellow-emitting variant of green fluorescence protein, immobilized on the gold electrode surface, robust enhancement or decrease of fluorescence was induced by applying negative or positive bias, respectively. This previously unappreciated phenomenon was then implemented as a protein-based microdisplay. We then sought to solve the mechanism for the cathodic enhancement utilizing the characteristic optical properties in the three different fluorescence proteins. From the simultaneous electrochemical and fluorescence measurements in Venus, we found a strong correlation between the fluorescence modulation and the current reflecting cathodic hydrogen evolution, which led to a hypothesis that shift in the protonation-deprotonation equilibrium of the chromophore driven by hydrogen evolution at the metal surface underlies the phenomena. The hypothesis predicted that voltage dependency should be also found in the green-to-red photoconversion of fluorescence protein which is known as a protonation-dependent process. The hypothesis was verified by observing clear voltage dependency for the photoconversion in KikGR, an engineered photoconvertible fluorescence protein, at the interface. We then addressed how the shift in protonation equilibrium is driven by hydrogen evolution. The analysis using iR-phuruolin, a fluorescence protein variant with the inverse pH-sensitivity revealed the existence of an interface-specific mode of protonation-deprotonation reactions, where the protonation equilibrium is directly coupled to the cathodic hydrogen evolution. The interface-specific mode is distinct from that conventionally seen in protein in the bulk solution where the protonation patterns of the constituent titratable residues are determined through the local environmental acid-base equilibrium. The potential applications based on this interface-specific mechanism are then discussed, including the spatially resolved monitoring of hydrogen evolution reactions at the near-neutral condition. Fluorescent Protein The original Green Fluorescent Protein (GFP) was discovered by the researchers back in the early 1960s when studying the bioluminescent properties of a blue light emitting bioluminescent protein called aequorin together with another protein isolated from Aequorea victoria jellyfish and that another protein was eventually named the Green Fluorescent Protein [1]. GFP like fluorescent proteins have been discovered in other organisms including corals, copepods, sea anemones, lancelets, zoanithids [2]. GFP can be modified because the genetic code and amino acid code is well known [3]. Modifications allow for GFP to fluoresce with different colors such as blue (BFP), yellow (YFP), cyan (CFP), red (RFP) [4]. Their physiochemical phenomena can be used for various biological and medical research [5,6]. Advances such as, Förster resonance energy transfer (FRET), a fluorescence microscopy application was developed with GFP and permitting the researchers to use even more specific and powerful applications of fluorescence for their imaging [7]. last ten years, many new RSFPs (Reversibly photoswitchable fluorescent proteins) have been developed and novel applications in cell imaging discovered that rely on their photoswitching properties [8,9].

Abstract: Nanogenerators are a tiny device that can harvest small-scale ambient energies. Carbon nanotubes (CNTs) have been integrated into the device to boost the performance and increasing the efficiency of harvested electrical energy. Multiwall carbon nanotubes (MWCNT) have lower electrical properties compared to single wall carbon nanotubes (SWCNT). However, single wall carbon nanotube is difficult to grow in mass scale and subject to higher production cost. This paper aims to use MWCNT as an active material in triboelectric nanogenerator. The samples were prepared by spin coating of MWCNT on ITO glass at various concentrations. XRD result shows that MWCNT mainly present at crystal planes of (0 0 2), (1 0 0) and (0 0 4). The device has produced maximum current density of 165 μAm^-2, and power density of 1,289 μWm^-2. Apparently, the concentration of MWCNT in the solution to fabricate the device plays critical roles on the current output of the device. The application of multiwall carbon nanotube based triboelectric nanogenerator is promising for low cost self-powered nanogenerators.

Abstract: The dye-sensitized solar cell is one of the most promising solar cells as an alternative to conventional silicon-based solar cells. The advantages of DSSC compared to conventional silicon-based solar cells are the easy fabrication process and low cost. In general, DSSC consists of semiconductor materials and dye as a photoanode, a catalyst at the counter electrode, and an electrolyte. The problem is that the DSSC performance is not optimal in the light utilization process. One of the ways to improve DSSC performance is by increasing photon absorption. A method that can increase photon absorption on DSSC is by adding a light scattering layer (LSL) using TiO₂ microparticles. The technique used in this study for the optical model is the scattering theory and numerical methods using the Finite Differential Time Domain (FDTD). The scattering intensity and incident photon intensity are used for the electron generation process. The result of electron generation is used to model electrically to obtain the value of the short circuit current density and the open-circuit voltage with the diffusion differential equation. DSSC with LSL has higher efficiency than DSSC without LSL. The results obtained from this study DSSC with LSL has an efficiency of 5.5%, Jsc 16 mA/cm², and an open-circuit voltage of 0.6184 volts. DSSC without LSL has an efficiency of 4.9%, Jsc of 14.5 mA/cm², and an open-circuit voltage of 0.6073 Volt.

Abstract: In the past few years Prussian Blue Analogues (PBAs), as advanced metal organic framework compounds, have gathered a lot of attention due to its three-dimensional structural network and properties. PBAs are famous for their multitasking ability as they have shown an efficient role in scientific research and development with their excellent performance in various fields like, electrochemical sensors, photocatalysis, electrocatalysis, and energy storage applications. Apart from their high-tech productivity, PBAs also have some other advantages associated to them such as benign nature, economical and facile synthesis, extensive surface properties, higher theoretical capacity and exceptional electrochemical behavior which makes it more promising material for energy storage application. To further tune its properties according to the application of interest, the chemical modification by metal incorporation is the most commonly adopted strategy. For this purpose, the major research is done in the synthesis of bimetallic PBAs. The presence of metal atoms with different oxidation states can bring about dramatic reinforcements like finer microstructures with better crystallographic features, ultimately giving rise to more stable electrochemical behavior. In this article, we aim to list out all the bimetallic PBAs with focus on the synergistic effect of more than one metal within the structure of PBA and thorough analysis of their Electrochemical properties in energy storage applications.

Abstract: Palm oil fuel ash (POFA) and palm oil clinker (POC) are by-products from palm oil mill which disposed as environmental polluting wastes. Excessive sand mining activity by sand traders for the widely used concrete production, harms the river’s ecosystem. Success in discovering alternative material that can function as partial sand replacement for concrete production would reduce the dependency on natural sand supply. This research investigates the effect of POFA as a partial fine aggregate substitute on the workability and compressive strength of palm oil clinker lightweight aggregate concrete. Five mixes have been prepared by integrating diverse percentage of POFA ranging from 0, 5, 10, 15 and 20 as fine aggregate substitute by weight of sand. Then, concrete mixes were subjected to slump test and compressive strength test. The outcomes have shown the combination of 5% POFA in this lightweight aggregate concrete produces concrete with the targeted strength and has the potential to be used for structural application. Utilization of POFA in concrete would save the consumption of river sand and contribute to sustainable environment.

Abstract: Concrete is the most important material in building construction. It had been used widely around the world and is made of cement, fine aggregates, coarse aggregates and water. These materials come from natural resources which had a depletion and environmental pollution issues. On the other hand, tonnes of waste are generated around the world especially in developed country which are having rapid industrialization, increasing population growth, technological developments and urbanization. Most of the waste materials from those causes are not recyclable. The methods managing of the waste materials are usually done by dumping in landfills or burning. Thus, in order to overcome both issues, alternative replacements from waste materials can massively give huge differences to the industry that will reduce the usage of natural resources and gives benefits to the industry itself and also to the environment. Studies on waste materials had been conducted by many researchers before. Hence, in this paper, some materials which are coal bottom ash, slag, ceramic waste and glass powder will be discuss as waste materials that have been used from many backgrounds of industries. This paper attempt to summarize the investigation of the following materials as substitution materials in concrete, with the following discussion. The properties such as workability, compressive strength, ductility etc. of these replacement materials are compared with the normal concrete. A lightweight concrete that is safe and eco-friendly will be produced as a construction material. This shows that some of the materials can improve the performance of concrete itself. Thus, this study is crucial in finding the other waste materials that can act as a replacement.