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Mathematical and artificial neural network modeling for describing the infrared drying process of Moringa oleifera leaves and evaluation of product quality
(2025-08-01)
Thuy, Nguyen Minh
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Hao, Hong Van
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Giau, Tran Ngoc
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Minh, Vo Quang
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Tai, Ngo Van
Moringa oleifera leaves were used in the infrared drying method for powder production. The moisture ratio datasets during drying at different temperatures were fitted with eight thin-layer drying kinetics and analyzed by an artificial neural network (ANN). The goodness of fit was evaluated using the value of the coefficient of determination (R2), the chi-square (χ2), and the root mean square error (RMSE). Results indicated that drying time was between 40 and 95 min at a temperature of 55 to 70 °C. Among the mathematical drying models used, the Wang and Singh model best described the drying kinetics of Moringa leaves. But comparing with the ANN model—a machine learning-based model—it showed higher prediction capacity than the mathematical model did. For Moringa leaves dried at temperatures between 55 and 70 °C, the R2, χ2, and RMSE values for this model ranged from 97.85 to 99.59%, 0.0007 to 0.0029, and 0.0228 to 0.0503, respectively. Effective moisture diffusivity (D<inf>eff</inf>) values varied between 1.908 × 10−11 and 3.875 × 10−11 m2/s, with an activation energy of 43.92 kJ/mol. The drying temperature also influenced the bioactive compounds in Moringa leaves. The vibrant color of the powder was produced by drying Moringa leaves at 65 °C for 50 min. The powder had 5.85% moisture, 31.97% protein, 61.05 mg/100 g β-carotene, 62.82 mg QE/g total flavonoid content, and 1789.65 mg/100 g calcium content.
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Effecting on electrical performance of Methylammonium Lead Chloride Iodide perovskite films composited by reduced graphene oxide for controlling double Schottky barrier
(2024-06-01)
Butsriruk, Kwanruthai
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Sriwong, Chaval
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Ruttanapan, Chesta
Semiconducting perovskite thin films are cheap to fabricate and can be coated on fluorine-doped tin oxide (FTO) substrates by using simple techniques such as the solution deposition method. In this work, we show that the improved electrical performance of perovskite film produces that of single crystals in an ambient atmosphere. Herein, Methylammonium Lead Chloride Iodide (MAIPbCl<inf>2</inf>) is played as perovskite films, which were composited with different weight percent (wt%) of rGO from 7 to 10. All samples in this work were presented with physicochemical, electrical, and optical properties. However, the challenge of this work is the electron scattering at the grain boundaries as a result of the double schottky barrier. The best decreasing the double schottky barrier yielded a maximum conductivity of 68.72 ± 0.95 S/cm, a low sheet resistance of 5.47 ± 1.64 Ω, a decrease in the lowest oxygen vacancy, and an increase in the grain size from 27.89 nm (of MAIPbCl<inf>2</inf>) to 34.96 nm at room temperature for the MAPbCl<inf>3</inf>-8 wt% rGO composite, which also revealed that this strategy significantly helped to improve the performance of the film. Furthermore, temperature dependence for MAIPbCl<inf>2</inf>-rGO composites demonstrates this high electrical conductivity from room temperature to 323 K, with highest electrical conductivities of 78.68 ± 0.01 S/cm and the activation energy of 0.18 eV at 313 K for 8 wt% rGO. Therefore, MAIPbCl<inf>2</inf>-rGO composite films demonstrated the enhancement of performance of MAIPbCl<inf>2</inf> films; this is next promising for perovskite films in the future.
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Mathematical modelling of roselle seeds (Hibiscus sabdariffa L.) drying kinetics
(2023-08-01)
Thuy, N. M.
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Tram, N. B.
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Cuong, D. G.
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An, L. T.
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Duy, H. K.
Roselle seeds (Hisbiscus sabdariffa L.) are among the seeds that are high in nutrients and can be useful in several applications. Through the drying process, the seeds can be preserved for a long time. The roselle seeds were oven-dried at different temperatures 55, 60, 65 and 70°C, giving different outlet values for yield and final moisture. A total of five empirical mathematical models (Newton, Henderson and Pabis, Logarithmic, Diffusion approach and Page) were selected to describe and compare the drying characteristics of roselle seeds at respective drying temperatures. The adequately suitable drying temperature was found to be 70°C with a drying time of 4 hrs. The effective moisture diffusivity was calculated using the Fick diffusion equation. The results showed that the moisture content of the seeds gradually decreased with time. The effective diffusivity coefficient of moisture transfer varied from 5.4262×10-10 to 1.074×10-9 m2/s over the temperature range investigated. Mathematical models were fitted to the experimental data and by statistical comparison, the Page model represented drying characteristics better than the other equations with the highest R2 (0.998) and the lowest values of χ2 (0.00033) and RMSE (0.00023) observed for drying air temperature of 70°C. The dependence of moisture diffusivity on temperature was described by the Arrhenius equation, with the estimated activation energy being 43.08 kJ/mol within 55 to 70°C. Based on the selected model, it is possible to predict the moisture change during the drying of roselle seeds and thereby better control the process.
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Physicochemical characteristics of ashes deposited on a wall flow diesel particulate filter of compression ignition engine
(2023-06-01)
Rodvanna, Sattatad
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Srilomsak, Mek
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Nuthong, Chaiwat
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Charoenphanich, Chinda
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Masomtob, Manop
The investigation of physicochemical characteristics of metal oxide ashes, deposited on a diesel particulate filter, was conducted using electron microscopy, energy dispersive spectroscopy, X-Ray fluorescence, and X-Ray diffractometry techniques. Iron is the main component of deposited ash on the DPF, and other ash components consisted of elements such as silicon, calcium, copper, sulfur, phosphorus, zinc, aluminum and minor chromium. It was clarified that this metal oxide ash has catalytic effect that contributed to an enhancement of soot oxidation. The apparent activation energies of soot oxidation on SiC powder and metal oxide ashes powder are approximately 169 and 135 kJ/mol, respectively.
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An experimental study on dielectric response of the crosslinked polyolefin (XLPO) insulation of the unshielded cable under electric field and heat flux
(2021-05-19)
Singhasivanon, Jakawan
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Jirasuwankul, Nirudh
Nowadays, crosslinked polyolefin cables (XLPO cables) are more popular and more famous for electrical insulation. In order to study and analyze the characteristics of insulation. The polarization and depolarization of current measurements (PDC measurement) is one of the advance methods that can compute and provide dielectric reaction parameters. In this paper, aim to study dielectric response of the XLPO insulation of unshielded cables under electric fields and heat fluctuations by measuring permittivity (ϵ′, r), conductivity (σ) and dissipation factors (Tan δ). The experimental results indicate permittivity is rather constant at different field strengths and temperatures and are similarly to XLPE insulation. It is also found that the activation energy of XLPO insulation is 0.77 eV. Future more, action energy in this research can excite electrons or ions in valent band within insulations to change the state from non-conductivity to conductivity.
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Evaluation of loss factor of mineral oil and alternative fluids with temperature normalization
(2020-07-01)
Maneerot, S.
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Nimsanong, P.
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Pattanadech, N.
This paper proposes the evaluation of loss factor of mineral oil and alternative fluids the natural ester (FR3) with temperature normalization. The oil samples (i.e., mineral oil, natural ester, and palm oil) were prepared for experiments. The oil samples were dried at 70 °C under 200 mbar in the controlled temperature oven and then cooled down to ambient temperature. The moisture contents of the oil samples were measured according to ASTM D1533. The test cell, according to IEC61620, was employed in these measurements. The polarization currents, ipol(t), of such oil samples under electric field stress of 0.2 kV/mm with a temperature range from 30 to 70 °C were measured, The test results are summarized in this paper. The step response measurement results were analyzed for conductivities, permittivity, and loss factor value. It was found that increasing temperature causes increasing conductivities but decreasing permittivity of oil samples.
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On-line measurement of activation energy of ground bamboo using near infrared spectroscopy
(2019-04-01)
Sirisomboon, Panmanas
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Posom, Jetsada
On-line measurement of activation energy (Ea) is very important in supporting the thermal conversion process. The main objective of this study was to evaluate the Ea of ground bamboo using near infrared spectroscopy in real time. 80 bamboo samples with different diameters were selected using random sampling. Ea was determined using the Coats-Redfern method, and Ea of reaction order (n) at n = 1 and n≠1 was investigated. The performance of on-line measurement predicted by PLS modelling for Ea at n = 1 and Ea at n≠1 showed coefficients of determination of 0.781 and 0.714, respectively; standard error of prediction of 5.249 and 6.858 kJ/mol, respectively; and bias values of −1.0628 and −1.871 kJ/mol, respectively. Both PLS models were found to be fair and could be applied toward screening. The results showed that the vibration bands of lignocellulosic components (CH<inf>2</inf>, hemicellulose, cellulose, and lignin) highly influenced model development. Moreover, internal relationships were identified among Ea, the pre-exponential factor (A), and n, such as A (1/min) = 63251 × e0.2200×Ea (at n = 1), A (1/min) = 33719 × e0.2267×Ea (at n≠1), and n = 0.008 × Ea+0.254. These relationships can be used to evaluate A and n if Ea is known. In the case of this study, Ea was forecasted using an NIR model.
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Morphology and oxidation kinetics of CI engine’s biodiesel particulate matters on cordierite Diesel Particulate Filters using TGA
(2017-02-01)
Karin, P.
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Boonsakda, J.
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Siricholathum, K.
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Saenkhumvong, E.
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Charoenphonphanich, C.
The impact of small compression ignition (CI) engine operation conditions and fuel properties on diesel and biodiesel particulate matters (PMs) quantity using opacity smoke meter is investigated. The biodiesel engine’s PMs are around a half of diesel engine PMs under the same engine operation conditions. Morphology of both engine’s PMs are also studied using a Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and image processing method. The average primary nanoparticle sizes of diesel and biodiesel engine’s PMs are approximately 34 nm and 32 nm, respectively. The result shows that engine operation condition and fuel property are strongly impact on the quantity and size distribution of primary nanoparticles emission. PM oxidation kinetics on conventional cordierite Diesel Particulate Filters (DPFs) powders by Thermo-gravimetric analysis (TGA) is also successfully studied. The calculated apparent activation energies of biodiesel engine’s PM oxidation on conventional cordierite DPFs powders are lower than that of diesel engine’s PM and carbon black because of unburned oxygenated molecule. The calculated apparent activation energy of biodiesel engine’s PM and diesel engine’s PM oxidize on conventional cordierite DPFs powders with pure air are in the range of 109 ~ 131 kJ/mole and 117 ~ 130 kJ/mole, respectively. It might be expected that smaller primary nanoparticle size of biodiesel engine’s PMs and bio-oxygenate unburned hydrocarbon can promote more PM oxidation rate during vehicle’s DPF regeneration process.
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Oxidation kinetics of small CI engine’s biodiesel particulate matter
(2015-04-01)
Karin, P.
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Borhanipour, M.
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Songsaengchan, Y.
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Laosuwan, S.
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Charoenphonphanich, C.
Particulate matters (PMs) oxidation kinetics by Thermo-gravimetric analysis (TGA) was successfully studied. The chemical content percentage of PM can be divided by oxidation temperature zoning in three main regions which are moisture, unburned hydrocarbon (HC) and carbon. It is clearly observed that the amount of each region is strongly depending on engine operating condition, the amount of unburned HC in low load condition of the engine load are larger than that of high load condition. The calculated apparent activation energies of biodiesel PM oxidation are lower than that of diesel PM and carbon black because of unburned oxygenated molecule. The calculated apparent activation energy of biodiesel and diesel PMs oxidize with air is in the range of 147–157 kJ/mole and 153–165 kJ/mole, respectively. The results of this research would be used as basic information for design and develop removing process of particulate matter emitted from engine combustion which using in diesel and biodiesel fuels.
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Evolution of Intermetallic Compounds between Sn-0.3Ag-0.7Cu Low-silver Lead-free Solder and Cu Substrate during Thermal Aging
(2012-01-01)
Mookam, Niwat
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Kanlayasiri, Kannachai
The growth, transformation, and lattice structure of intermetallic compounds formed between Sn-0.3Ag-0.7Cu lead-free solder and copper substrate were investigated. Dip soldering was used to initiate the reaction between the solder and substrate. An η-Cu <inf>6</inf>Sn <inf>5</inf> intermetallic phase possessing a hexagonal lattice structure was found at the as-soldered interface. Thermal aging at a number of conditions resulted in the formation of a Cu <inf>3</inf>Sn intermetallic phase between the Cu <inf>6</inf>Sn <inf>5</inf> layer and the copper substrate. e{open}-Cu <inf>3</inf>Sn with an orthorhombic lattice structure was found together with hexagonal Cu <inf>3</inf>Sn. Subsequently, the activation energies of the intermetallic phases were calculated and compared to results obtained from the literature. The comparison showed that good agreement existed between the findings from this study and literature data within a similar temperature range. © 2012 The Chinese Society for Metals.

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