Applied Mechanics and Materials Vol. 916

Abstract: Porous ceramic is a heat-resistant porous material with extensive applications, especially for filtering inclusions in aluminum casting industry. To meet local need for these filters, ceramic foam is fabricated by mixing raw materials including kaolin and chamotte as base material, wood sawdust (WSD) as pore-forming agent (PFA), and carboxymethyl cellulose (CMC) with water as binder. WSD content variable: 0%, 5%, 10%, and 15% was used for this research. The mixture was then formed with dry-press method and sintered at 1200°C to form mullite-based local filters. Characterization of samples morphology, composition, and phase were done using SEM-EDS, XRD, and XRF, while its mechanical and thermal properties were characterized by conducting STA, porosity, coefficient thermal expansion (CTE), permanent linear change (PLC), and flexural strength testing. Results showed an increase of WSD addition on the local filter increased the formation number of open-type pores in fiber form on the ceramic microstructure, no significant heat exchanges from decomposition were detected, increased CTE value from 0,0071 to 0,0371%, PLC from 0,0025 to 0,0345%, apparent porosity from 33,29 to 47,95%, and water infiltration from 18,27 to 33,05%, as well as decreased flexural strength from 13,48 to 6,33 MPa and density from 1.82 to 1.43 g/cm³.

Abstract: Research on ceramic filters, needed in the aluminum casting industry because of their ability to filter inclusions, has been done. This study's primary material to make ceramic or local filters is kaolin. The manufacture of local filters in this study uses the dry press method. In this study, potato starch with a composition of 5%, 10%, and 15% acted as a pore-former in the local filter. The local filter burned to a temperature of about 1200°C to obtain the mullite phase. Local filter characterization used SEM, XRD, XRF, and DTA. Several tests were carried out in this study, including Permanent Linear Change (PLC) test, thermal expansion test, flexural strength test, and porosity test. The results obtained in this study show that pores on the local filter are not open, have a prolate shape, and have an average pore size of 10 to 55 m. Burning kaolin up to 1200°C proved successful in obtaining the mullite phase. Another result of this study, the more starch content added to the material, the greater the shrinkage and expansion of the material; the highest shrinkage value on the material is 0.17%, and the highest expansion value of the material is 0,29%, the 15% values owned by potato starch. It is different in the flexural strength value, which has the highest value with 0% potato starch at 14.14 MPa and the lowest value with 15% potato starch at 5.39 MPa.

Abstract: Dolomite is widely used in the construction, glass ceramics, iron and steel, pharmaceutical industries, as a source of CaO and MgO and as thermal energy storage material. Thermal decomposition analysis of natural dolomite of the so-called Jeddih limestone has been carried out. A thermogravimetry analysis (TGA) in the air evaluates the thermal decomposition of dolomite. The natural dolomite has been analyzed by x-ray flourescence (XRF) and x-ray diffraction (XRD) to test crystal structure and decomposition phase, fourier transform infra-red (FTIR) was utilized to identify the presence of functional groups. The particle morphology was observed by scanning electron microscopy. TGA curve shows that the thermal decomposition of dolomite occurs in two stages. The first stage is in temperature range of 600 - 779°C and the second one is at the temperature 779°C. The results are in line with the XRD and FTIR measurements. Which shows that calcite begins to grow at a temperature of 600°C and MgO phase is observed at 700 - 900°C. Moreover, CaO phase starts to be found at 800°C.

Abstract: The use of natural fibers in composite is increasing day by due to eco-friendly nature of the fibres and reuse of waste. Natural fibers can be classified according to their source of origin such as plant fiber, mineral fiber, and animal fiber. In the present article, epoxy was taken as the matrix and wool fiber for reinforcement with flax flax fiber for fabricating the composite using the hand layup technique. The impact of the hybridization of flax and wool fibers on the mechanical properties of natural fiber reinforced polymer composite was investigated. These fibers were blended in varying percentages with fixed fiber content of 5% [(100% flax fiber), (40% wool/60% flax fiber), (50% flax/50% wool fiber), (60% wool fiber/40% flax), (100% wool fiber)] with epoxy resin and sampled as F5, WF23, WF2.5, WF32, and W5 respectively. Tensile strength, flexural strength, and impact strength were investigated through experimentation. All hybrid composites outperformed non-hybrid wool fiber composites in terms of mechanical properties. The wool fiber is poor in mechanical strength which was compensated by high strength of flax fiber.

Abstract: Pollution caused by Waste Plastic is one of the major environmental problems being faced by developed as well as developing countries, here tile fabricate samples by using bottle caps, sand, one sample was fabricated by mixing these materials in a metal vessel in the micro oven at 200°C for 20 and 10 min respectively by varying the sand composition, the results are analysed by testing the sample under before and after soaking conditions by ranging the pressure from 100 to 800 KN/m², results state that sand, wastage plastic tile sample exhibit more strength than Sand and Cement tile sample

Abstract: This project aims to evaluate the mechanical properties of composite materials reinforced with jute, banana fibres, and groundnut husk powder reinforced with LY556 resin and HY951 hardener. The study investigates the potential of these natural fibres and powders as a replacement for traditional synthetic fibres in the development of lightweight and environmentally friendly composite materials. The composites will be prepared by blending the natural fibres with a thermosetting resin matrix. Four samples are fabricated by using hand lay-up technique. The composition of the composites will be optimized by varying the fibre volume fraction and the ratio of the different types of fibres, and the mechanical properties of these materials will be evaluated using standard ASTM testing procedures. The results of the study will be used to analyze the effects of fibre content, and the inclusion of groundnut husk powder on the mechanical properties of the composites, such as tensile test, flexural test, compression test and hardness test. The findings of this research could contribute to the development of new and improved composite materials that are sustainable, cost-effective, and have desirable mechanical properties for various applications, such as construction, automotive, and packaging industries.

Abstract: The utilization of the moving bed biofilm reactor (MBBR) has been identified as a promising technology for reducing water pollutants. This study focuses on designing a novel bio-carrier using 3D printing technology for use in an MBBR for wastewater treatment. The bio-carrier is made of polypropylene filament with four variations in specific surface area. The study investigates the relationship between the specific surface area and the amount of adhering biofilm on the bio-carrier. Results show that type-4 bio-carrier with a specific surface area of 1438.16 m²/m³ and a pore diameter of 1.8 mm to 4.9 mm has the highest mass of biofilm attachment at 2.598 grams. This research provides insights for designing bio-carriers with suitable pore diameters and specific surface areas for improved MBBR performance in wastewater treatment.

Abstract: Fish feed is the crucial aspect of aquaculture activities, 70% of production costs are spent on feed availability. However, the high price of commercial feed causes a decrease in farmers' profits, so a solution is needed to reduce feed costs. Food waste has a good potential to be used as a fish feed material. The fermentation of food waste should improve its quality and ensure that food waste is safe to use as feed material. As a result of various tests of Proximate, FTIR, SEM, and Physical Quality test it has been shown that the fermentation process can significantly improve the nutritional quality of food waste without changing the functional groups and the reduction of the particle size after the fermentation process is also capable to improve the physical quality of feed. We conclude that the fermentation process is the best method of improving the physical and chemical quality of food waste and the addition of fermented food waste meal to feed did not negatively affect the physical quality of feed produced.

Abstract: Photocatalyst activity relates to the active surface area between pollutants and catalyst compounds. The insertion of Al atoms as a substantial defect in ZnO structures can reduce the particle size thus the active surface area increases. Another way to raise the photocatalytic activity of ZnO is by combination with other oxide materials such as TiO₂ (Titanium dioxide). In this study, the ZnO-Al:TiO₂ powder was successfully prepared via the sol-gel method using zinc acetate dihydrate as a precursor, 0.5wt% of aluminum nitrate nonahydrate as a dopant precursor, and TiO₂ anatase. In order to understand the role of the combination of these two metal oxides, the concentration ratio of ZnO-Al and TiO₂ was varied by 1:1 (ZAT) and 4:1 (ZA4T) under low (150°C) and high (450°C) temperature calcination. Photocatalytic testing was carried out using a 3.2 ppm methylene blue (MB) solution under UV-A lamp irradiation for 120 minutes. The high calcination temperature facilitates the growth of ZnO-Al. Besides that, the different ratio concentrations and calcination temperatures produce different defect states in each sample. The most optimum results in the photocatalytic activity performed by ZnO-Al:TiO₂ 150°C (ZAT 15) with degradation rate constant (k) of 0.033/min and efficiency of 97% for MB removal. The unexpected zinc vacancies defect is estimated produce at the samples in high-temperature calcination. This defect type can accelerate electron-hole pair recombination. In Addition, samples with high-temperature calcination were considered to have lower hydroxyl/oxygen bonds on the surface thus affecting the photocatalytic performance.