Papers by Keyword: Particle Size

Abstract: This study presents a report on the energy content enhancement of biomass derived from palm kernel shells (PKS) by varying the sample sizes using a developed hammer mill machine. A hammer mill was designed, simulated, and constructed to efficiently mill palm kernel shells into various particle sizes. Finite Element Analysis (FEA) was performed on the hammer mill’s frame and shaft, ensuring the structural integrity of the machine under operational loads. The machine’s rotor, crushing chamber, hammers, sieves, and prime mover were strategically engineered to achieve precise size reduction while maintaining operational efficiency and durability. The energy content of the selected biomass was evaluated for the control PKS sample and the milled PKS sample of two different particle sizes (0.4 and 0.6 mm). The main objective of this research was to examine palm kernel shells' energy potential by analysing the impact of particle size reduction on their energy content. To evaluate the energy characteristics of the processed biomass (grain size reduction), proximate and ultimate analyses were conducted on each particle size fraction, assessing parameters such as moisture content, volatile matter, ash content, fixed carbon, elemental composition (carbon, hydrogen, oxygen, nitrogen, and sulfur), and calorific value. The results revealed a direct correlation between particle size and energy content, with finer particles exhibiting improved combustion properties due to increased surface area and enhanced reactivity. It is found that higher carbon content of the milled PKS samples (54.5% at 0.4 mm and 48.37% at 0.6 mm), representing 49.4% and 43.04% enhancement, respectively, over the control PKS sample before the milling process was achieved in this study. The results of which yield a 3.36% energy content increment in terms of particle size variation from 0.4 to 0.6 mm, highlighting enhanced energy efficiency in this work. The attained reduced nitrogen and sulfur content of the milled samples in this work contributes to lower greenhouse gas emissions, making them a more environmentally sustainable biofuel option. These findings elucidate the potential of particle size optimization as an effective approach for improving the energy content of PKS, thereby enhancing its suitability as a clean and efficient bioenergy source.

Abstract: In the fabrication of fuel cell electrodes, applying catalyst ink onto a substrate is crucial. The performance of the proton exchange membrane fuel cell (PEMFC) is subsequently impacted by how the catalyst is applied onto substrate as well as in terms of its resulting morphology. In this study, a direct catalyst ink spraying approach was done in order to investigate transfer efficiency and surface morphology for different concentrations of ink. The concentration of catalyst ink used in the spraying process are 0.5, 1.0, 1.5, 2.0 and 2.5 mg/ml with fixed loading of 1.0 mg/cm². The transfer efficiency of the catalyst inks was calculated neglecting human error during spraying. The coating thickness and distribution of the resulting catalysts were analysed via Field Emission – Scanning Electron Microscope (FESEM).

Abstract: This study compared the effectiveness of bare zero-valent iron nanoparticles (B-nZVI) and starch-stabilized zero-valent iron nanoparticles (S-nZVI) in immobilizing Pb and Cd from lead-acid battery waste soils. Both B-nZVI and S-nZVI were prepared in almost identical manner using the technique of reducing ferric chloride with sodium borohydride. X-ray diffraction (XRD) and dynamic light scattering (DLS) analyses confirmed that polydisperse B-nZVI and S-nZVI were synthesized. XRD and DLS analyses showed that B-nZVI and S-nZVI had different surface properties. To assess the immobilization capability of B-nZVI and S-nZVI, a composite soil sample was collected from an automobile lead-acid battery waste dumpsite. The soil sample had a pH of 3.85 and Pb and Cd levels of 16,674 mg/kg and 41 mg/kg, respectively. Single extraction procedures using 0.01M CaCl₂, 0.1 M HCl, and 0.05 M EDTA were used to simulate phytoavailable Pb and Cd in the soil studied. Batch immobilization analysis showed that Cd was mobile in the control but immobile in B-nZVI and S-nZVI treated soils. Pb was however not immobile in either the control or treated soils. The mobility of Pb however decreased with increasing doses of S-nZVI and 0.003 g of S-nZVI was needed to make Pb completely immobile in soil. Batch immobilization also showed that S-nZVI was 1.8-2.49 times more efficient in immobilizing Pb than B-nZVI. Simulated phytoavailability of Pb was in the order of EDTA > HCl > CaCl₂ > H₂O while simulated photoavailable Cd was in the order of HCl > EDTA > H₂O > CaCl₂.

Abstract: This study investigates Halloysite Nanotube (HNT) dispersibility in ethanol-water mixtures – 0% and 10% ethanol at 100, 300, and 500 ppm HNT concentrations. Overall, the study finds that changes in HNT concentration linearly affect the response variables and showed that the 10% ethanol solvent has a higher zeta potential, smaller particle size, higher viscosity, and settling velocity. The enlargement of HNT particles at 10% ethanol while keeping better stability than water solvent is unexpected and can open novel studies about the dispersion of HNT in this solvent system.

Abstract: Incorporation of vitamins into food, feed, and personal care is realised through microencapsulation of their nanoparticle in powder form. Vitamin E consisting of α-, β-, γ-, and δ-tocopherols and α-, β-, γ-, and δ-tocotrienols, is a powerful antioxidant that has been used in food applications and supplements. However, due to its fat-soluble characteristic, the application of tocotrienol in food and beverages is still limited. Therefore, microencapsulation of tocotrienol via emulsification could help maximise the dissolution of tocotrienols during processing and prolong the product’s shelf lives. In this study, factors affecting the particle size, including surfactant concentration, stirring time and speed, and mixing temperature for the preparation of tocotrienol emulsion, were investigated. Emulsions were prepared using 12 wt% surfactant concentration, 800 rpm stirring for 30 minutes. Emulsions with 190 nm particle size were found stable after 30 days storage at ambient temperature.

Abstract: This paper evaluated the swelling of graphite resin electrodes developed for utilization in the electrochemical treatment of gold mining wastewater. Graphite-resin electrodes were developed from used dry cells and resin using non-heat treatment processes (segregation). The Microstructure of the electrode was determined using a scanning electron microscope (Carl Zeiss Smart Evo 10) to ascertain the composition of the electrode. The swelling property of the electrodes was measured using the standard method through a combination of gold mining wastewater and chloride salt solutions. Effects of operational factors (particle size, percentage binder and compressive “compacting” pressure) on the swelling of the electrodes were monitored and evaluated statistically (using analysis of variance). Weibull probability distribution (2 and 3 parameters) was applied to the swelling through Microsoft Excel Solver and Moment Likelihood Method to ascertain the usefulness of the electrode in environmental pollution control through computation of reliability. The study revealed that the swelling was in the range of 1.48 % to 2.24 %, particle size (F_5,20 =196.48, p = 2.76 x 10^-16), percentage binder (F_4,12 =181.58, p = 1.27 x 10^-10), and compressive pressure (F_3,12 = 106.69, p = 6.43 x 10^-9) were significant factors that influence swelling of graphite-resin electrode at 95 % confidence level. the values of α and β for 2-parameters Weibull distribution are 63.162 and 15.098, and 1.265 and 10.089 for MSE and MLM methods, respectively. The Table shows that the values of α, β and θ for 3-parameters Weibull distribution are 3.679, 8.097 and 0.168, and 4.350, 7.165 and 0.198 for MSE and MLM methods, respectively. It was concluded that particle size and compacting pressure are significant factors that had an effect on the swelling of graphite resin electrodes for treatment water and wastewater.

Abstract: The particle size of the rice straw and boiling duration play an essential role in the applicability of this material. They affect the rice straw’s mechanical properties, which is one of the critical parameters in bio-based material development. In order to have a clear insight into the effect, rice straw particle materials form without a hot press machine route to avoid bias due to the material response to the pressure and heat transfer effect. The rice straw particle incorporates corn starch as a bio-adhesive with an equal composition ratio. It turns out that finer particle sizes (mesh 60 and 40) achieve higher tensile strength compared to mesh 18 particles. The optimum boiling duration is two hours. Longer boiling times reduce the mechanical properties of rice straw particle-based materials.

Abstract: Solid oxide electrochemical cells (SOCs) consisting of solid oxide fuel cells (SOFCs) and solid oxide electrolysis cells (SOECs) are widely studied for the development of high-efficiency energy generation and storage devices. To investigate the effect of precursor particle size on the microstructural and morphological properties of the electrode, glycine nitrate process and solid-state reaction ball-milling were utilized as synthesis methods for Nickel oxide-scandia stabilized zirconia (NiO-ScSZ) powders. The synthesized powders were then screen-printed on commercial YSZ solid electrolyte substrates. The structure and morphology of the sintered electrodes were investigated. Particle size analysis (PSA) revealed that NiO-ScSZ precursor powders obtained from GNP ball-milled had a smaller average particle size than solid-state reaction ball-milled powders. For the sintered NiO-ScSZ films, cubic structures of both NiO and ScSZ have been observed from the X-ray diffraction (XRD) patterns. A better porous morphology with less agglomeration and better dispersion of NiO and ScSZ phases was revealed by the scanning electron microscopy (SEM) micrographs and elemental mapping for the GNP-ball-milled synthesized powders.

Abstract: Green or renewable energy is important to attain a sustainable low carbon economy and the use of hydrogen has been an alternative solution for the unreliable continuous supply of these energy sources. Solid oxide electrochemical cells is a promising technology for hydrogen generation in which the LSM-YSZ is one of the important component materials for this application. In this study, LSM-YSZ will be deposited on the YSZ substrate via screen-printing. Screen-printing is an easy and simple set-up that offers film quality control. Specifically, the study aimed to deposit a porous LSM-YSZ thin film, as well as to determine the effect of the particle size of the starting powders on the quality of the deposited film. Two synthesis methods for the powders were utilized before screen printing, the solid-state reaction (SSR) ball milling, and the glycine nitrate process (GNP). Results showed that a porous and even thin film with uniform distribution of LSM and YSZ was obtained after the screen printing. Moreover, the GNP powders produced a smaller particle size, a more porous morphology, and a thinner film when screen-printed compared to the SSR ball milled.

Abstract: The zinc oxide nanoparticles were synthesized to investigate the ultraviolet light absorbance and transmittance for applications of UV protection. Zinc oxide nanoparticles were characterized by photon cross-correlation and ultra-violet spectrophotometers. The results show that the synthesized zinc oxide nanoparticles have the mean diameter of ~35 nm of main particles with particle size distribution range from ~11 nm to ~80 nm.The use of synthesized nanoparticles achieved transmission levels of over 95 % in the UVA regions at the wavelength range of 320-400 nm.