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Magnesium oxide (MgO) is an essential material for producing solid oxide fuel cells (SOFC) sealant. It can be derived from bittern waste. The common approach uses membrane electrolysis, which requires complex equipment and high energy costs. Alternatively, direct electrolysis can be taken using proper parameters to maximize the production rate. This work analyzes the process according to the input voltage, which varies between 10 and 16 V. The designed working voltage is suitable for direct conversion from renewable sources such as photovoltaic. The evaluation shows that the working voltage notably affects the reaction rate of the bittern solution. The working voltage of 16 V has the lowest power factor (2.58), while the working voltage of 10 V indicates the highest power factor of 3.56. It makes the reaction rate for the working voltage of 10 V extremely low, causing the lowest production rate of MgO with only 4.27 g. Oppositely, the suitable working voltage improves the production of MgO up to 75%. Microscope evaluation indicates that the produced MgO from the process has a lower agglomeration concentration after heat treatment at 700 °C, which is desirable to ensure effective fuel transfer in fuel cell apparatus. [ABSTRACT FROM AUTHOR]

The application of solar dryer through greenhouse (GH) model as drying method for crops-based product is extremely important in industrial scale agriculture, especially in developed country. The drying model is considered environmentally friendly since it utilizes solar power as the main drying energy. However, the fundamental operational aspect of the basic GH is less discussed according to the drying mechanism of the dried product. In this work, three small-scale drying model are evaluated: open drying (OD), natural convection GH (NCGH), and forced convection GH (FCGH). The drying product is potato, which can be taken as an essential agricultural product in modern world. The OD model has the lowest mass loss rate which less than 50 % of the water from product can be evaporated. The operation of both GH is satisfactory, resulting more than 60 % moisture evaporation. The drying characteristic indicates the two-step failing rate which makes the mass loss fluctuation from the process. The highest mass loss is observed during the constant rate period around 21 % for FCGH and 18 % for NCGH. In addition, the detailed analysis on the effect of each process is discussed in this work. For example, the presence of hair-like structure and the movement of the pith of dried potato during the process. Also, a higher drying rate from NCGH and FCGH initiate the gelatinization and compartmentalization, resulting a substantial water evaporation of the product. It confirms the important correlation of the drying process and water diffusion mechanism of the dried product. The finding from this study can be taken as a vital reference for improving the operation of GH solar dryer. [ABSTRACT FROM AUTHOR]

A weigh-in-motion (WIM) sensor is a versatile unit that dynamically monitors the vehicle load, which is suitable for high-mobility traffic. However, the dynamic measurement requires sufficient physical property for the sensor housing in order to maintain the effective reading process and response time. The present work assesses the potential of reinforced silicone rubber as a compressive sensor housing. The reinforcement uses calcium carbonate (CaCO3) and spring wire. The tensile strength of the composite rubber increases up to 56.5% by adding 15 wt% CaCO3. The maximum deflection of the composite is obtained at 12.92 mm at a load of 160 kg, which is higher compared to the rubber (maximum load of 70 kg). The spring within the composite maintains sufficient deflection profile around 180-220 kg, indicating a better mechanical strength. The response time for reinforced composite rubber is less than 200 ms (milliseconds), demonstrating a notable reading performance. Moreover, surface observation through scanning electron microscope (SEM) implies suitable material conformity between rubber and CaCO3, making the proposed method can be taken as a convenient manufacturing method for producing compressive sensor housing. [ABSTRACT FROM AUTHOR]

The present work assesses phase stabilized HW (hydrocarbon wax) with nano additives through liquidus aging treatment. The aging treatment is performed by storing the sample in the liquid phase at 130°C for 250 hours. The treatment is designed to imitate the actual process of thermal energy storage (TES) system which experiences continuous operation. It helps to evaluate the TES material for long-term operation consideration. The sample performance is assessed according to the heating and cooling rate change before and after aging treatment. The finding indicates a severe decrement in the heating rate of thermal conductivity enrichment (TCE)-HW up to 24.4% and 7.5% for the discharge rate. The phase-stabilized HW performs better according to its heating rate, which only decreases by around 10.9% and the discharge rate by only 1.2%. The heating profile for HW shows a distinctive phenomenon, indicated by a two-step temperature spike of 6.8°C and 11.8°C at the solid-solid and solid-liquid transition. Contrary to that, the SHW presents a suitable profile where the temperature increases steadily until 86.3°C with the average heating rate around 2.97°C/min. The surface observation shows that the phasestabilized polyethylene (HDPE) decreases the potential of void formation which correspond to the plasticity effect. As a result, the SHW maintains suitably the distribution of nano additives after aging treatment. Thus, phase stabilization is critical to ensure stable operation of HW with nano additives for the TES system. Moreover, the finding can be used to mitigate the potential performance deterioration for TES system which uses thermal enrichment. [ABSTRACT FROM AUTHOR]

Heat storage technology has a critical role for a number of applications involving renewable thermal energy (such as solar water heater). The application of wax (n-octacosane/ OCT) as a medium for storing heat brings many positive influences for the system. However, the operational curve is undesirable for the OCT-based energy storage, which makes it necessary to use a binding material. The present work employed LD-class polymer (LDPE) and linear-LDPE as binding materials for OCT. The mixture is prepared through mechanical hot stirring, which comes into two categories: SOCT1 (OCT/LD) and SOCT2 (OCT/LLD). The assessment through the calorimetry method shows an increment in transition temperature for SOCT with a value of 2.1 °C and 5.5 °C. This contributes to the variation of fusion energy for solid-liquid change for both materials, which amounted to 132.05 J/g (SOCT1) and 113.4 J/g (SOCT2). Another assessment related to its chemical and structural phase demonstrates that SOCT has an identical structure to OCT, indicating that SOCT is mixed physically. At the operational level, SOCT is more optimal than OCT according to the indicator related to charge and discharge duration for energy exchange. SOCT1 demonstrates a short plateau line as the indication of a steady transition between 65.4–67.9 °C, while SOCT2 indicates the average heating rate, which is higher than for single OCT. The heat releasing curve for SOCT1 varies at a lower value between 1.92 °C/min and 0.77 °C/min, while SOCT2 has the lowest variation, which is only 0.17 °C/min. Moreover, the self-insulation for SOCT2 has the lowest rate, which is only 0.3 °C/min. The evaluation and analysis from this work show that SOCT is reliable to increase the operational curve of OCT and can be implemented for thermal systems [ABSTRACT FROM AUTHOR]

This research investigates the impact of varying the slope of the top mold in the gravity casting process of aluminum alloy (A356). The casting mold slopes were adjusted to 7°, 12°, and 17° angles, and the study integrates software analysis (Altair, 2021.2) with physical examinations to assess potential defects in the casted products. The findings from both approaches exhibit a consistent pattern, revealing notable defect porosities in molds with slopes of 7° and 12°. Radiography examinations provide insights into defect distribution within the hub wheel rim, particularly pronounced in molds with slopes of 7° and 12°. This observation suggests that disturbances in air and heat distribution impede the solidification process within the mold. Metallography profiles further highlight the presence of phases a (Al), ß (Si), and the eutectic region in the casted product. Defect severity is prominently manifested in a fractured profile, particularly for products cast with a 7° slope. In contrast, a higher slope of 12° results in localized porosities and effectively mitigates defect distribution. The most favorable outcome, devoid of substantial defects, is achieved with a 17° mold slope, successfully passing stringent quality checks. [ABSTRACT FROM AUTHOR]

Thermal storage is an essential equipment for storing excessive heat, especially for water heating systems. The present work proposes a preliminary study to maximize the operation of thermal storage using photovoltaics as the primary source for charging the heat storage material. The assessment indicates the concept is feasible, where the output power from photovoltaics can be directly converted to heat using a heating element. The power ratio is considerably high (up to 38.6%), resulting in the maximum temperature of the heat absorber material (water) increasing to 43.2 °C. The final assessment using suitable phase transition material shows that steady phase behavior is essential to maximizing the temperature profile of the material. It is achieved using stabilized-hexadecanoic acid, which shows a transient phase transition at a temperature of 54.2 °C, reducing the possibility of heat loss with an average temperature rate of 0.54 °C/min in the discharge stage. This finding proves the proposed concept is applicable, while further improvement can be done to adjust the suitable power output from photovoltaic and storage tank arrangement for the actual system. Despite that, the result is expected to accelerate the utilization of photovoltaics as reliable solar renewable technology. [ABSTRACT FROM AUTHOR]

In this study, an indirect burner system for solid biomass fuel is designed. The design is motivated by the need to solve the problem related to a direct burner system, such as slagging and high pollutant emissions due to the high-temperature burning process. Therefore, the utilization of an indirect burner is expected to improve the reliability of the solid biomass combustion process. It also can be used to reduce coal consumption by using an indirect burner where the working fluid reaches a relatively higher temperature before entering the boiler. The design used the first principle method for creating the regenerator heat exchanger. The regenerator consists of a mantle and coil heat exchanger. The test used solid biomass fuel for the combustion process where the working fluid first enters the mantle heat exchanger and then the coil heat exchanger. As a result, the mantle absorbs sufficient heat losses from the combustion chamber with the highest temperature increment of 19 °C. The warm water from the mantle then flows to the coil arrangement within the combustion chamber. As a result, the highest temperature of the coil is 84.5 °C. The heat transfer rate for the coil and mantle is 57.2–85.6 and 124.9–141.5 W. The key finding is that the combined regenerative heat exchanger can deliver a higher transfer rate. This can be achieved since the heat exchanger utilizes the same flow distribution, increasing the mean temperature differences at the inlet. Thus, it can produce an average heat transfer rate of 210.5 W. Therefore, energy consumption for coal or other fossil fuels can be reduced significantly. The data can be used for further improvement of the existing boiler system and help to increase the thermal efficiency of the system. [ABSTRACT FROM AUTHOR]

Paraffin is well known thermal energy storage with the high latent heat of fusion. Unfortunately, low thermal conductivity and low melting temperature inhibit large-scale applications for lower temperature applications like solar water heaters and desalination. The addition of high thermal conductivity material can increase the thermal conductivity of paraffin and increase the melting temperature of paraffin. In this study, a new approach is taken by using volcanic sand as thermal conductivity enhancement material. The properties of the sand are examined. The chemical composition of the sand is dominated by Fe (51.23%), Fe2O3 (23.24%) and SiO2 (11%), which are known as good thermal conductivity materials. Six different compositions of paraffin/sand (weight ration) are tested to observe the melting and vapor temperature of the composite. Adding sand (with granule size of 44 µm) by 30 wt % can accelerate the charging rate by 25% compared to pure paraffin, where the discharging rate is increased significantly by 17.8%. The supercooling degree of the composite is only 1 °C, where pure paraffin has a supercooling degree by 8 °C. The charging and discharging characteristics for each sample are discussed in detail within the article. Overall, the addition of volcanic sand improves paraffin's charging and discharging rate, reducing the supercooling degree and can be considered a convenient method to improve the paraffin performance as latent heat storage. [ABSTRACT FROM AUTHOR]

The addition of nickel as catalyst and particle size reduction through milling process is considered as the best approach for MgH 2 properties to be thermodynamically and kinetically more favorable. The recent development in MgH 2 is done by adding Ni (14–16 wt%) and particle size reduction through simple mechanical milling at a large sample of 100 g. The research sequences are easy to adopt for the implementation and sustainable research of MgH 2. Starting from the moisture test to the milling process, continue with particle size distribution (PSD) for the milled sample and final moisture test after PSD. Some critical finding from our research includes high capacity storage of Mg 84 :Ni 16 above 5 wt% H 2 within 20 min at 573 K, the effect of moisture content on system performance and the different effect of carbon (C) in the system at specific temperature and pressure that may have. Image 1 • High storage capacity of MgH 2 up to 5 wt% by adding 16 wt% Nickel. • Clear evidence of the effect of moisture content in MgH 2 performance. • A unique behavior of MgH 2 after adding 5 wt% C at specific pressure and temperature. • Ease of process to improve MgH 2 system for large sample capacity. [ABSTRACT FROM AUTHOR]

Increasing the operational aspect of heat storage system (HSS) contributes to significant positive influence on thermal system. As one fast-developing storage technology, modification of the material HSS (MHSS) has become crucial, specifically for organicbased MHSS. The drawbacks of poor phase transformation during energy intake and release (charging/discharging) of MHSS make undesirable performance for heat exchange and effective operation. To solve the problem, this work proposes modification of pure octadecanoic acid (POA) as MHSS by forming polymeric-embedded OA (PEOA). Evaluation is taken for the heating/cooling cycle operation of the HSS, showing positive contribution of the proposed method. The PEOA reduces the preheating duration by 14.8%, meaning the charging ratio can be improved effectively for the HSS. The effective energy ratio for PEOA is obtained with maximum value of 83.9%, which is higher than the POA with 74.8%. It is accounted for the application of PEOA since it allows a suitable solidification process on the heat release, making the maximum total heat loss drop to 17.9%. The profile observation using microscope electron demonstrates the stable formation of PEOA as a direct result of the presence of polymer structure of the composite. The result demonstrates the improvement in the operation of HSS unit, which is linked to the stabilized material, achieving a favorable energy ratio that potentially promotes better operation and control of HSS unit. Moreover, a consecutive discharge cycle for the heat storage tank (HST) using PEOA also brings positive outcomes and improves the heat discharge stage. [ABSTRACT FROM AUTHOR]

The present work assesses the manufacturing method for producing ceramic-based solid oxide fuel cells (SOFC) using compaction and sintering methods, which are combined by adding pore former to improve the porosity of the produced anode. The ratio of pore former varies between 5%, 10% and 15%. The base cermet material in this work is NiOYSZ (Nickle Oxide/Yttria Stabilized Zirconia), which is suitable for high-temperature SOFC. The base material is mixed with pore former at the given ratio, followed by ultrasonic cleaning. This work uses polyethylene glycol (PEG, 10%) as binder material. The produced slurry is then dried in electric oven, continued with the compaction process at a pressure of 135MPa and sintered for 4 hours at 1200°C. The addition of pore former leads to significant improvement in the porosity level, with the highest value of 16.67%. It contributes to the excellent performance of the produced anode, particularly for the permeability value. The NiO-YSZ with 15% pore former has the highest permeability value with average of 0.37 m². Moreover, the detailed permeability profile shows the baseline ratio for adding pore former is between 5% and 10%, which experiences significant variation in the porosity level and permeability value. [ABSTRACT FROM AUTHOR]