KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/kmitl/1

Browse

Search Results

Now showing 1 - 5 of 5

Some of the metrics are blocked by your
consent settings
Inhibiting the shuttle effect in sodium-sulfur batteries using Mo2CT2(T = S, O) MXenes: A DFT investigation
(2026-03-30)
Udomkijmongkol, Anan
;
Ruttanapunt, Piyaphat
;
Thasitha, Sirinee
;
Ounrit, Iyarat
;
Khammuang, Satchakorn
The rising demand for electrification has highlighted sodium–sulfur (Na–S) batteries as a promising energy-storage technology due to their high theoretical capacity, abundant materials, and low cost. However, their performance is limited by polysulfide dissolution, or the shuttle effect, which slows redox kinetics and accelerates capacity fading. This study employs the DFT method to investigate Mo<inf>2</inf>CT<inf>2</inf> (T = S, O) MXenes in 1T and 2H phases as potential anchoring materials for sulfur cathodes. All Mo<inf>2</inf>CT<inf>2</inf> structures effectively adsorb sodium polysulfides (Na<inf>2</inf>S<inf>n</inf>), demonstrating higher adsorption strength than commercial electrolytes and effectively suppressing the shuttle effect. Structural phase notably affects Na<inf>2</inf>S<inf>n</inf> adsorption on Mo<inf>2</inf>CS<inf>2</inf>, while its influence is minor for Mo<inf>2</inf>CO<inf>2</inf>. Higher Na<inf>2</inf>S<inf>n</inf>-Mo<inf>2</inf>CO<inf>2</inf> interaction arises from greater charge transfer from Na to O atom driven by higher electronegativity difference. Among the candidates, 2H-Mo<inf>2</inf>CS<inf>2</inf> and 1T-Mo<inf>2</inf>CO<inf>2</inf> exhibit higher binding energies than its counterpart and maintain metallic conductivity after Na<inf>2</inf>S<inf>n</inf> adsorption, benefiting electron transport. Gibbs free energy calculations indicate more favorable sulfur reduction pathways on Mo<inf>2</inf>CT<inf>2</inf> surfaces, along with reduced energy barriers for Na<inf>2</inf>S oxidation. Overall, Mo<inf>2</inf>CT<inf>2</inf> MXenes exhibit strong anchoring capability and catalytic activity, making them promising materials for mitigating the shuttle effect and enhancing electrochemical performance in Na–S batteries.
1
Some of the metrics are blocked by your
consent settings
Process design and muti-objective optimization of solid waste/biomass co-gasification considering tar formation
(2024-11-01)
Aentung, Tanawat
;
Wu, Wei
;
Patcharavorachot, Yaneeporn
Background: The co-gasification of solid waste and biomass to produce syngas is an environmentally friendly technology. Unfortunately, the tar formation in the solid waste/biomass co-gasification process would degrade the product gas quality and the overall process efficiency. Methods: In this study, the kinetics of the solid waste/biomass co-gasification is shown by the Aspen Plus simulation. Through the model validation and sensitivity analysis, it is validated that tar yield, syngas composition, and syngas yield are sensitive to gasifier temperature, steam-to-feed ratio (S/F), and blending weight ratio (B/W). It shows that the increase of the product gas yield (GY) increases CO<inf>2</inf> concentration in the product gas, but the tar yield is reduced. To address the sustainable solid waste/biomass co-gasifier, the multi-objective optimization (MOO) algorithm is implemented to maximize GY and minimize CO<inf>2</inf> concentration. For solving the MOO problem, the standard genetic algorithm (GA) coupled with response surface methodology (RSM) is performed to find the Pareto frontier plot, and the technique for order of preference by similarity to the ideal solution (TOPSIS) is used to determine optimal operating conditions. Significant Findings: Under the Pareto frontier plot and TOPSIS, a GY of 2.672 Nm³/kg, CO<inf>2</inf> concentration of 8.045 vol.%, and tar yield of 17.0617 g/Nm³ can be achieved under the optimal conditions of T = 1099.95 °C, S/F ratio = 0.79, and B/W ratio = 10.02. In addition, the CO<inf>2</inf> absorption using CaO is added to purify CO<inf>2</inf> up to 99.999 % of purity.
1
Some of the metrics are blocked by your
consent settings
Effects of hot air temperature on moisture reduction and drying time of turmeric in a closed-system herb dryer: kinetics and models
(2023-11-01)
Chindaruksa, Sirinuch
;
Bongkaew, Haruethai
;
Wardkein, Paramote
;
Chantrawongphisal, Borisut
The primary objective of this research was to devise a model focused on the drying kinetics of turmeric, utilizing a closed-system herb dryer to facilitate energy conservation. Drying turmeric within this closed-system herb dryer involves a heat source—specifically, an electric coil heater powered at 3500 W and a humidity controller. The drying condition includes an air volume of 0.039 kg/s, the temperature at 40, 50, and 60 °C with initial moisture of the turmeric at 667.53 %db. The result of drying turmeric was analyzed using a thin-layer drying model for 8 models: Newton, Page, Logistic, Henderson and Pabis, Logarithmic, Two-Term, Approximation of Diffusion, Midill et al. The result shows that Midill et al. equation was the best model for predicting the drying behavior of turmeric. Therefore, this insinuates that the Midill model is superior to its contemporaneous counterparts in terms of accuracy. It offered the highest coefficient of determination R 2 (0.9998, 0.9996, 0.9999), the most root mean square error (RMSE) (3.39×10−9, 2.37×10−5, 3.10×10−5), the last chi-square χ 2 (3.39×10−9, 2.85×10−5, 3.99×10−5), and a temperature of 40, 50, and 60 °C, respectively. The study revealed that implementing a closed-system herb dryer could potentially manufacture high-value commodities while preserving their fundamental attributes. The closed-system herb dryer has been ingeniously designed as a proficient approach to diminish the drying time and improve the end product’s quality.
2
Some of the metrics are blocked by your
consent settings
Effect of subcritical solvent extraction conditions on amount of γ-oryzanol and γ-tocopherol in dawk pa-yom rice bran oil
(2021-01-01)
Ruen-Ngam, Duangkamol
;
Thawai, Chitti
;
Sukonthamat, Sujitra
;
Khuwaranyu, Kittisak
This research focused on the subcritical solvent extraction of phytochemicals γ-oryzanol and γ-tocopherol from upland rice bran (Dawk Pa-yom variety, DY). Subcritical solvent extraction was conducted using a batch reactor. The temperature was varied in range from 80 to 120°C for 20 to 60 min. The solvents in use were ethanol, methanol, and water. γ-Oryzanol and γ-tocopherol were simultaneously analyzed by HPLC. Antioxidant activity was determined by a DPPH radical assay. Methanol was able to extract a higher level of γ-tocopherol than ethanol and water. Extraction by methanol gave higher antioxidant activity than ethanol. Even though water could not extract γ-oryzanol, it was able to extract substances with higher yield of antioxidant activity than either methanol and ethanol. Increasing the extraction temperature increased the oil yield, γ-oryzanol and γ-tocopherol paralleled increase antioxidant activity. During the extraction process, some degradation of antioxidants was observed, and this showed the importance of kinetics parameters in this research.
Some of the metrics are blocked by your
consent settings
Simple synthesis, kinetics and thermodynamics of rod-like Cu2(OH)PO4 microparticles and rod-like Cu4O(PO4)2 nanoparticles
(2020-08-01)
Kullyakool, Saifon
;
Boonchom, Banjong
;
Chaiseeda, Kittichai
Rod-like Cu<inf>2</inf>(OH)PO<inf>4</inf> microparticles were synthesized via a simple wet chemical reaction by mixing the solutions of CuSO<inf>4</inf>·5H<inf>2</inf>O and Na<inf>3</inf>PO<inf>4</inf>·12H<inf>2</inf>O at 90 °C for 24 h. Thermal transformation of the prepared Cu<inf>2</inf>(OH)PO<inf>4</inf> microparticles were related to endothermic dehydroxylation and its final decomposed product rod-like Cu<inf>4</inf>O(PO<inf>4</inf>)<inf>2</inf> nanoparticles were obtained. The XRD results indicated that Cu<inf>2</inf>(OH)PO<inf>4</inf> and Cu<inf>4</inf>O(PO<inf>4</inf>)<inf>2</inf> crystallize orthorhombic (space group Pnnm, D<inf>2h</inf> 12) and triclinic (space group P1‾, C<inf>i</inf> 1) phases, respectively. The thermal transformation mechanisms from Cu<inf>2</inf>(OH)PO<inf>4</inf> to Cu<inf>4</inf>O(PO<inf>4</inf>)<inf>2</inf> were expressed thought the relation of the graphical shape of isothermal combined with the non-isothermal multi-heating rate equation and kinetic models (P<inf>3/2</inf> and R<inf>2</inf>) to discuss the change of morphologies from microparticles to nanoparticles. Kinetic parameters and triplet thermodynamic functions of activated compound were determined and fully discussed. The obtained data will be useful for academic scientists and industrial researchers to apply these copper phosphates for special applications.

KMITL

Browse

Filters

Settings

Sort By

Results per page

Search Results