Key Engineering Materials Vol. 978

Abstract: Liquid-metal printed processes have been recently developed as a novel strategy to grow ultrathin 2D oxide materials, which are transferred from liquid-metal surfaces to substrates. In this study, we fabricated liquid-metal printing 2D tin oxide (SnO) nanosheets on SiO₂/Si and glass substrates. A large lateral-sized 2D SnO nanosheets of >100 µm and a thickness of approximately 6.3 nm was fabricated. The 2D SnO nanosheets exhibited a strong optical absorption in the ultraviolet and violet region and its bandgap was estimated to be approximately 2.9 eV. The 2D SnO nanosheets on glass substrates with patterned gold electrodes generated a photocurrent under ultraviolet (UV) light irradiation, demonstrating a potential for optoelectronic applications such as UV detectors.

Abstract: The abundance of rice husk in some regions of Southeast Asia makes it a potential feedstock for hydrogen synthesis. However, the information on economic and environmental feasibility of its conversion to hydrogen is lacking. This study aims to assess the techno-economic and life cycle sustainability of hydrogen production from rice husk via the thermochemical gasification method. The techno-economic analyses reveal that rice husk-based hydrogen conversion is more financially attractive than conventional hydrogen production technology. The results of the life cycle assessment are also promising, especially with the global warming potential of the rice husk-based hydrogen production being 99.7 % lower than that of natural gas steam reforming. Waste valorization of rice husk into hydrogen is therefore economically and environmentally viable.

Abstract: Drying process are important in many areas in the agriculture and food sectors, including increasing shelf life, improving transportability by reducing product weight or adding value to products. However, the main problem in the drying process is the relatively high energy consumption. Therefore, the development of energy-saving dryers is necessary. Based on the above reasons, this research aims to study the performance enhancement of heat pump dryers using R32 refrigerant by using heat recovery and nanofluid. The heat that is exhausted from the refrigerant by a heat exchanger. In this work, a Nano titanium dioxide (Ti₂O₃) was selected. Pork was dried under the conditions of drying temperature of 45, 50 and 55 °C and water flow rate in the heat exchanger at the front of the drying chamber of 2, 3 and 4 L/min. Criteria for evaluating heat pump dryer performance include drying rate, specific moisture extraction rate, specific energy consumption, heat pump dryer performance coefficient compared to heat pump dryers without nanofluid. The results showed that increasing the drying temperature and water flow rate in heat exchanger increased the drying rate, power and specific moisture extraction rate in the heat pump dryer using nanofluid. Whereas, the specific energy consumption was lower than the case without nanofluid. Increasing the drying temperature and the water flow rate in the heat exchanger had relatively little effect on the coefficient of performance (COP) of the heat pump dryer. Moreover, the study found that the coefficient of performance of heat pump dryer with nanofluid was in the range of 4.33 - 4.42.

Abstract: Performance of solar dryers were tested. In the past, to study the efficiency of solar dryers. A dryer with one drying chamber was built and tested by changing the conditions. In each experiment, the solar irradiance value is different, which can cause the results to be inaccurate. Therefore, in this study, a number of drying chambers are designed according to the number of experimental conditions to be studied during the same period. To reduce factors that will cause discrepancies in the experimental results. The solar dryer with 4 drying chambers was constructed in 1 unit and tested the performance of passive solar dryer (PSD) and active solar dryer (ASD). Air flowrate of ASD varied at 0.03 m³/s (ASD0.03), 0.06 m³/s (ASD0.06) and 0.09 m³/s (ASD0.09). Pork was selected as testing material with initial moisture content of 265% dry basis. Drying rate, solar dryer efficiency and specific energy consumption are criteria to evaluate of solar dryer performance. Result from the experimental was found that the performance of PSD is lowest compared with ASDs. Furthermore, it was revealed that the drying rate of ASD0.06 is higher than that for PSD, ASD0.03 and ASD0.09 by 22% 10% and 8%, respectively. Results from the experimental reveal the ASDs performance are higher than that of PSD. Moreover, it was found that the drying rate of ASD0.06 is higher than that for PSD, ASD0.03 and ASD0.09 by 22% 10% and 8%, respectively. Whereas, specific energy consumption of ASD0.06 is lower than that PSD, ASD0.03 and ASD0.09 by 26%, 11% and 9%, respectively. Finally, it was also found that solar dryer efficiency of PSD, ASD0.03, ASD0.06 and ASD0.09 are 11.68%, 13.34%, 14.89% and 13.73%, respectively.

Abstract: Biomass waste is one of the promising resource for the production of bio oil. In this study, a mixture of biomass waste will be pyrolyzed in the presence of activated carbon and zeolite as the catalyst. The catalyst concentrations were varied at 2%, 4%, 6%, respectively. While, the pyrolysis process was carried out at 500°C, for 60 minutes, with a nitrogen flow of 3 L/min. The highest bio oil yield was obtained the pyrolysis process by using zeolite with 35% at 4% w/w of the catalyst concentration. The lowest acid number obtained was 42.92 on 4% zeolite catalyst with rice husk biomass as the raw material, the best viscosity was obtained on 4% activated carbon multi feedstock with a viscosity value of 4.96 cP. The best density was obtained in multi feedstock with 4% zeolite catalyst and rice husk with 4% zeolite of 0.996 g/mL.

Abstract: This study aims to obtain an alternative fuel from plastic pyrolytic oil (PPO) that has similar properties to gasoline and diesel fuel. The process carried out is distillation, which is heating the PPO at a certain temperature so that light and heavy molecules will evaporate and turn into distillate plastic oil (DPO). The effect of temperature on the quality of the DPO was observed based on the color of the obtained DPO. Temperatures ranging from 120 to 350 °C were examined in this study. The cleaner DPO was produced at a temperature of about 120 °C, which indicated a light molecule of hydrocarbon similar to gasoline, while a little dark color was produced when the temperature was increased to 350 °C, which indicated heavy molecules of hydrocarbon similar to diesel. This research shows that distillation can produce alternative fuels with different grades depending on the applied operating temperature.

Abstract: The objective of this work is in order to investigate how the mechanical properties of bioplastics synthesized from chitosan and porang starch with sorbitol plasticizer are affected by varying drying temperatures. According to the study's findings, changes in drying temperatures significantly affect the mechanical properties of these bioplastics. This research provides valuable insights for developing environmentally friendly packaging alternatives of various drying temperatures starting from 50°C, 55°C, 60°C, 65°C, 70°C. The results of mechanical characterization show that at 50°C with 40% sorbitol, the plastic possesses a 17.32% elongation and 2.66 MPa tensile strength. At 50°C with 60% sorbitol, the tensile strength reaches 1.34 MPa and elongation is 34.43%. Meanwhile, at 65°C with 80% sorbitol, the tensile strength is 1.59 MPa and elongation reaches 37.80%. The plastic is also thermally tested using TGA-DTA, morphologically tested using SEM and its functional divisions are analyzed using FTIR to obtain further data about its properties.

Abstract: Pile has a textured structure that contains voids and cavities, and the texture hardens with repeated use. It is advantageous to numerically evaluate the hardening characteristics of the pile texture for the development of the products such as towels. Then, the objective of this study is to establish an objective method for evaluating the hardening of the pile due to repeated use. In particular, to determine product specifications, it is necessary to define the conditions under which measurement results are stable. Therefore, for proper design of pile products, objective test methods for repeat use of the pile must be identified. This article reports the effect of repeated indentation testing with a spherical probe on towel samples folded in two to form four layers. A contact theory based on Hertzian theorem is used to evaluate the stiffening of the towel due to repeated indentation. For the properties evaluated in this extended contact theorem, the stiffening behavior is discussed by comparing the changes in the results of 20 repeated tests. In this discussion, the critical times of the indentation test are analyzed to quantify the characteristics of the stiffening behavior of the cotton towels. Analyzing the indentation times shows that critical conditions for the number of tests can be defined.

Abstract: In order to promote the sustainable growth of the wool industry and protect consumers' legitimate rights, rapid identification of the country of origin for wool of the same type is deemed crucial. This research presents a computer graphic recognition training model that utilizes median and Wiener filtering techniques to effectively reduce noise in the raw wool fiber images. Employing a support vector machine as the classifier and integrating a polynomial kernel function, this model achieves swift and accurate identification of Chinese and Australian Merino wool fibers. Experimental results underscore that following image recognition training, the model attains an impressive 92.5% comprehensive and precise identification rate for Chinese and Australian Merino wool fibers, effectively distinguishing the origin of wool from the same category. This approach not only provides a valuable reference for identifying the origin of similar wool types but also holds the potential to standardizing the wool fibre material market and assuring the consumer’s confidence on wool products.

Abstract: A deep understanding on the intermixing of components in hybrid yarn or composite structures is decisive in order to develop hybrid structures with desired properties. This paper presents the development of a versatile procedure for the determination of the degree of fiber mixing in yarns and composites based on microscopy images auto-segmented by a neural network. The procedure is based on the quantification of blend irregularity values and blend homogeneity. For this purpose, functions of spatial point patterns analysis have been used to investigate the blend uniformity of yarn and composite cross sectional areas. The results show that the trained neural network model for segmentation of images has an accuracy of 92 %, indicating that the method is capable of accurately assessing the location of fibers in hybrid struc-tures. The results of the spatial point patterns analysis reveals a correlation between the blend value and the properties of yarns and composites. The proposed method provides a fast and reliable way to evaluate the hybrid structures, which could be used as a tool for quality control and process optimization.