Kasetsart University
  • Bangkok, Thailand
Recent publications
Anaerobic fermentation is one of the ways to realize the recycling, harmlessness and reduction of food waste. The potential of methane production via anaerobic fermentation was analyzed by the model compounds of food waste after hydrothermal pretreatment, and the micro-particle effect of hydrothermal pretreatment on matrix was verified by the change of physicochemical properties and morphology characteristics of model compounds of food waste in hydrothermal group, and the influence of hydrothermal pretreatment on anaerobic fermentation methane production was explored. From the perspective of particle size, the hydrothermal groups had good decomposition characteristics. With the increase of hydrothermal temperature, the surface morphology changed from smooth to rough, and the specific surface area increased from 0.29 m²·g⁻¹ in the control group to 2.82 m²·g⁻¹ in the hydrothermal group at 200 °C. In addition, the model compounds of food waste were anaerobic fermented under the condition of constant temperature water bath (55 °C). The results showed that the methane yield of 140 °C hydrothermal group was the highest (0.368 NL·g⁻¹ VS), which increased by 27.78% compared with the control group, and the methane generation performance of the fermentation process was improved. Through material balance and energy analysis, it is revealed that hydrothermal pretreatment coupled anaerobic fermentation could achieve zero waste discharge and partial energy recovery.
Bananas (Musa spp.) are an important source of pro-vitamin A, derived from carotenoids. Some cultivated bananas originated from intra-specific hybridization resulting in genotypes which are diploid (AA) and triploid (AAA) genomes that are the most important bananas for desserts. The accumulation of carotenoids and transcripts of genes related to carotenoid biosynthesis during fruit development and ripening in cultivars carrying the banana A genome (AA and AAA) were investigated. The accumulation of total carotenoids was greatest in ‘Khai Kasetsart2’ (KK2; AA) and ‘Sa’ (SA; AA), and comparatively lower in other cultivars. The predominant carotenoids in this fruit were β-carotene and lutein, with a small amount of α-carotene, which correlate with the orange-yellow pulp color (in particular KK2). In contrast, Leb Mu Nang had the lowest total carotenoids during fruit development while lutein and β-carotene in Hom Thong increased with fruit ripening. MaPSY2a gene expression in KK2 and SA cultivars occurred throughout fruit development but declined during fruit ripening. The expression of MaLCYB, MaLCYE, MaCHYB, and MaCHYE genes increased throughout fruit development and during fruit ripening resulting in β-carotene and lutein high content. In cultivars with low carotenoid levels, MaLCYB gene expression was reduced, while the MaLCYE, MaCHYE, and MaCHYB genes were up-regulated during fruit ripening. Besides, the MaCCD4 gene (a gene associated with carotenoid turnover) had lower expression throughout fruit development and ripening in KK2 compared to the other cultivars. These results suggested that the different carotenoid accumulation patterns in the cultivars could be attributed to differential gene expression and A genome composition.
The total phenolic content and antioxidant activities of the organic spent coffee ground obtained from different brewing methods were investigated. Among various brewing methods, the organic spent coffee ground showed the highest total phenolic content (TPC) and antioxidant activities and was selected as raw material for extracting phytochemicals using ultrasound assisted extraction (UAE) with different temperature, time, and solvent ratios. In terms of extraction time, the TPC and antioxidant activities were continuously increased until the extraction time reached to 40 min and then dramatically decreased indicating the appropriate extraction time. The extract with highest TPC (78.85 mg garlic acid equivalent/ml antioxidant crude extracts) and antioxidant activities was obtained when extracted with UAE at 50 °C, solvent ratios of 1:20 g/ml and 40 min. The assays of 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ATBS) and ferric reducing antioxidant power (FRAP) were detected at 717.11 µM Trolox/antioxidant crude extracts, 711.23 µM Trolox/antioxidant crude extracts, and 2401.90 µM Ammonium ferrous sulfate/antioxidant crude extracts, respectively. When applied the antioxidant crude extracts from organic cold brew spent coffee ground into low fat pork sausage at 1.00%, the improvement of TPC and antioxidant activities was obtained. After storage for 14 days, the TPC and DPPH scavenging activity was increased to 18.07 mg garlic acid equivalent/100 g pork sausage and 159.76 µM Trolox/100 g pork sausage, respectively, while the 2‐thiobarbituric acid reactive substance values were reduced to 9.18 g malondialdehyde/100 g pork sausage. The rancidity of the sausage was ceased, and the shelf-life was prolonged when the extract was added. © 2022 Onamon Chongsrimsirisakhol and Tantawan Pirak. Published with license by Taylor & Francis Group, LLC. © 2022, Published with license by Taylor & Francis Group, LLC.
Rheological and tribological analyses were compared between two polysaccharide-based stabilizing systems (xanthan gum and corn syrup) of a traditional herbal sweet sauce. Imitative testing showed that XG sauces have a greater surface stickiness but lower stringiness than CS sauces. Oscillatory (O) shear tests showed that XG sauce exhibited greater gel strength and elasticity. Between the frequency range 100.0–0.1 rad/s, both sauces showed weak gel characteristics and long-term stability to sedimentation. In rotational (R) shear tests, both sauces displayed the shear-thinning flow behavior. The XG sauce had a higher consistency index (K) and a slightly lower flow behavior index (n). In time-dependent O/R/O measurements, XG sauce showed a lower viscosity under high shear but higher regeneration after 40 s; structural elasticity was comparable under low shear. Type of stabilizing system affected boundary and hydrodynamic lubrication regimes; CS sauce showed greater potential to lower the friction between interacting surfaces.
Concrete breakout failures with acutely damaged concrete are one of the main problems caused by expansion anchors under tensile loading. In this study, the prevention of concrete breakout is investigated by post-installed reinforcement (PRs). Experimental and numerical studies were conducted to look into the effect of the PRs on the expansion anchors subjected to tensile loads. The 3D Rigid Body Spring Model (RBSM), which is based on discrete analysis at the mesoscale, was used as supporting numerical research. On pullout capacity, displacement, failure mechanism, and concrete breakout geometry, both experimental and numerical analyses were undertaken. The numerical analysis also looked at internal stress, strain, and concrete cracking. In general, the anchors with the PRs had steady displacement (ductile) and less brittle failure compared to the anchors without the PRs. The significant finding was in the failure mode, where severe concrete damage and concrete breakout failures were prevented by the PRs. The internal tensile stress of concrete was concentrated around the wedges of the anchors (interlocked area). The contribution of the PRs was shown by high strain values at around their mid-length. Additionally, due to the PRs, concrete cracking was less, mostly generated in the region between an anchor and its PRs. The utilization of PRs could be a method to protect concrete from breakout failure.
We provide a simple method to synthesize tetraphenylethylene-modified aza-BODIPY dyes (AZB-TPE1 and AZB-TPE2) with aggregation-enhanced emission. Single-crystal X-ray method, electrochemical experiments, and TD-DFT calculations were used to understand more about their electronic and photophysical properties. The intramolecular energy transfer between the TPE donor and the aza-BODIPY acceptor was observed from both dyes, with 84–97% energy transfer efficiencies and large pseudo-Stokes shifts of 395 – 406 nm. Aggregation studies in THF/water solution showed increased fluorescence in the aggregated form. X-ray crystal structure of AZB-TPE2 suggested the reduction of intermolecular pi-pi interactions between the structures. Finally, these NIR-emitting particles with superior water dispersion and biocompatibility demonstrated amazing features in bioimaging applications.
Three new aggregation-induced emission (AIE) molecules have been prepared by incorporation of the tetraphenylethylene (TPE) unit to the triazaborolopyridinium (TBP). The compounds exhibit broad absorption from 470 to 510 nm and emission from 530 to 600 nm in various solvents. The TPE-linked TBP, TT-1, and the compound with a phenylene bridge, TT-2, demonstrated high fluorescence quantum yields and solvent-sensitive behaviors due to twisted intramolecular charge transfer (TICT). In contrast, the derivative with a thiophene bridge, TT-3, showed less solvent dependence and low fluorescence quantum yield. The presence of a thiophene moiety led to redshift in the absorption and emission spectra due to a lower energy gap, confirmed by cyclic voltammetry (CV) and density functional theory (DFT) calculations. All derivatives displayed AIE in THF-water mixtures at water contents higher than 80% v/v. TT-1 was encapsulated within phospholipid-connected polyethylene glycol (DSPE-PEG) by nanoprecipitation, yielding fluorescent nanoparticles with the average sizes of 80.7–83.7 nm. In cell imaging experiments, the resulting [email protected] nanoparticles (NPs) showed no toxicity to H1299 lung carcinoma cells at concentrations up to 50 μM and were successfully internalized by the cells after 2 h incubation. Finally, the biodistribution of [email protected] NPs was studied in a bladder cancer murine model. In vivo and ex vivo images indicated that the NPs were highly localized in the stomach of the mouse after 2 h post-injection and showed a small uptake by the tumor after 4 h post-injection.
The present article concerns with thermohydraulic performance, flow friction and entropy generation analysis in a heated tube contained with louvered winglet tape (LWT). The experiment was conducted in a uniform heat-fluxed test tube for turbulent fluid flow, Reynolds number (Re) ranging from 4760 to 29,260. The purpose of the LWT insert is to produce streamwise vortices assisting to induce impinging-jets onto the tube wall and to decline the pressure loss through the louver mounted on the winglet aside from providing rapid mixing of fluid flow. In the present experiment, the louvered winglets were mounted periodically on a double-sided straight tape with six different louver angles (θ = 0 ˗ 90°) and three winglet pitch ratios (PR = 1 ˗ 2) at a single relative winglet height (BR = 0.25) and a fixed attack angle (α) of 30°. There were two-types of LWT arrangements: inline and staggered louvered-winglet tapes (I-LWT and S-LWT). To examine the optimum thermohydraulic performance, an influence of θ at each PR on the rate of heat transfer and friction loss inside the tube was explored. The measured results disclosed that the Nusselt number (Nu) and friction factor (f) from using both types of LWTs rise considerably with the reduction of PR and θ. The entropy generation (S˙gen') was declined with the decrease in Re, PR and θ where the minimum S˙gen' was obtained for the I-LWT tube at PR = 1, θ = 0° and lowest Re. The peak thermal enhancement factors (TEF) of the S-LWT and the I-LWT were, respectively, around 2.22 and 2.18 at similar PR = 1, θ = 45°. The Nu, f and TEF correlations for using LWT insert were also reported.
The heat transfer capability was investigated for water flow across a cylinder under the influence of 25 kHz ultrasound in a rectangular duct with a Reynolds number (Re) in the range of 110–2,140. A heating cylinder with constant heat flux was set at the center of the duct. The transducer was mounted on the top wall, and its location was set at -2, -1, 0, +1, and +2 diameters from the cylinder in the streamwise direction. Thermocouples and thermochromic liquid crystals (TLCs) were used to characterize the heat transfer mechanism on the heating surface. In particular, a visualization technique using TLCs was developed to obtain temperature results on a cylindrical surface. The temperature of the heating surface was reduced by the acoustic cavitation process with ultrasonic involvement. The local Nusselt number was increased by 2.37-fold by the waves at a cylindrical angle of 90° and Re value of 110 when the transducer was also located in the middle of the duct. Furthermore, the results indicated that ultrasonic effects could be transported along with the flow when the transducer was located upstream. In addition, when the waves were released downstream, they affected the heat transfer of the cylindrical surface at low Re values. The friction loss in the system was investigated by comparing the pressure drops with and without ultrasound. Depending on the position of the ultrasonic transducer, the pressure drop ratio was in the range 0.88–1.27. Furthermore, the areas most affected by ultrasound were identified using the TLC measurement method, and regions of augmented heat transfer were detected locally on the shaded and unshaded sides of the cylinder. A predictive formula was proposed for the local Nusselt number ratio with and without ultrasound as a function of the Re value, spanwise direction, and cylindrical angle.
Typically, oxidizing agents (such as H2O2) are necessitated for vanillic alcohol (VLA) conversion; nevertheless, intensive consumption of H2O2 is required due to the stoichiometric chemistry, and metal catalysts are usually required to improve conversion of VLA by H2O2. Nevertheless, for pursuing the goal of sustainability, it would be highly desired to develop an oxidizing agent-free and metal-free process which can selectively oxidize VLA to vanillic aldehyde (VAE). The aim of this study is to propose activated carbon fiber (ACF) as a highly effective catalyst for VLA conversion to VAE without using metals and oxidizing agents. At 120 °C within 30 min, ACF could enable CVLA = 100% with SVAE = 100% without using metals/oxidants. The effect of radical scavengers and ESR analyses further reveal that the oxidation of VLA to VAE by ACF could be attributed to reactive oxygen species derived from ACF-mediated aerobic reactions.
Chukrasia tabularis A.Juss. is a canopy tree widely distributed in Asia and commonly used for construction-grade timber. While the residues resulting from the timber exploration constitute the major source of waste, other parts of the plant remain underutilized. Therefore, aiming the valorisation of a major residue resulting from C. tabularis wood industry, the leaves were here investigated on their potential content in bioactive constituents, but also on their capacity to modulate mediators and enzymes engaged in metabolic disorders, particularly those involved on the development and progression of diabetes. HPLC–DAD–ESI/MSⁿ and UPLC-ESI-QTOF-MS² characterization of a methanol extract obtained from the leaves, allowed the identification of 25 phenolic constituents, quercetin-3-O-rhamnoside being identified as the main bioactive. The leaf extract and the major flavonoid (quercetin-3-O-rhamnoside) were investigated on their impact towards a series of targets involved in the physiopathology of diabetes. The extract displayed significant scavenging properties against nitric oxide and superoxide radicals, inhibiting also lipid peroxidation and aldose reductase activity. While no noteworthy effects were noted on pancreatic lipase and α-amylase activity, the extract strongly inhibited α-glucosidase (IC50 = 21.14 µg/mL) and proved to be ca. 5 times more effective than the benchmark drug, acarbose. Moreover, the leaf extract significantly inhibited also 5-lipoxygenase (5-LOX) (IC50 = 13.12 µg/mL). Kinetic studies on α-glucosidase and 5-LOX activity disclosed a mixed type inhibition. Furthermore, C. tabularis extract reduced LPS-induced overproduction of NO, L-citrulline and IL-6 in activated RAW 264.7 macrophages. When individually assayed, quercetin-3-O-rhamnoside significantly contributed to the antiradical properties and inhibitory effects of the extract upon the enzymatic targets, but other phenolic bioactives appear also to underlie the recorded anti-inflammatory effects. Taken together, our results demonstrate that the leaves of C. tabularis are rich in phenolic constituents with a great potential to improve metabolic disorders. The evidenced bioactivity of this industrial product might feed R&D programs for the development of new drugs that might simultaneously improve glycaemic, oxidative and inflammatory benchmarks in diabetic patients.
CO2-assisted propane dehydrogenation has been developed in propylene production technology to deal with thermodynamic equilibrium limitations. However, the rational design of catalysts is a crucial challenge in achieving high catalytic performances. Herein, we report the successful fabrication of highly dispersed PtZn alloy on hierarchical zeolites for CO2-assisted propane dehydrogenation through the reverse water–gas shift reaction (RWGS). Compared with monometallic Pt, the synergistic effect of PtZn plays a crucial role in both direct propane dehydrogenation and RWGS, resulting in an outstanding catalytic performance with a high turnover frequency (TOF) of 1.82 × 10⁴h⁻¹. From the catalytic point of view, Pt-Zn alloy surfaces facilitate the equilibrium shift in propane conversion by consuming produced H2 through RWGS with weakening CO-metal surface interaction revealed by operando studies and DFT calculations. These findings illustrate the conceptual design of alloy catalysts and allow insights into the mechanistic details of CO2-assisted alkane dehydrogenation.
The initial steps in the growth process of atomic layer deposition (ALD) of titanium dioxide at room temperature (RT) were investigated using tetrakis(dimethylamino)titanium (TDMAT) and H2O as the titanium and oxygen sources, respectively, in the adsorption and reaction processes, respectively. Density functional theory at the B3LYP/6-31G(d,p) level was used to calculate the process characteristics. Energy pathways were used to investigate the reaction mechanism in the pre-adsorption, adsorption and reaction steps and the results were compared with other published experimental data. The calculated pathways implied that all the relative energies were located below the reactant levels, indicating the possibility of depositing the TiO2 thin film in ALD at RT. This work kinetically elucidated the agility of the ALD process and identified that the purity of the film could be improved with a temperature increase within a range of low temperatures. The effects were discussed of the levels of the computational method and cluster sizes on the realism of the reaction mechanism.
In modern times, the majority of the world's energy consumption is attributable to the heating and cooling of residential buildings. Because of this, the development of sustainable energy sources has increased dramatically, particularly in residential buildings, with the goal of reducing the amount of energy that is consumed within buildings. An extensive green roof system is one of the most effective ways to save energy. Not only does this lessen the impact that humans have on their surroundings, but it also has positive effects on people's health and the way their homes look. The purpose of this study was to investigate the thermal characteristics of green roofs installed on residential buildings in Qatar's hot and dry climate in order to assess their viability and determine how best to minimize energy usage. In the course of this investigation, five distinct heights ranging from 10 to 50 cm were taken into consideration to assess the energy efficiency of the roof. Of these heights, the height of 10 cm was found to be the most suitable height for planting in this environment. In addition, in order to evaluate the performance of roof energy, five plant leaf area indices with values ranging from one to five have been taken into consideration. Of these, the results indicate that the plant leaf area index is the plant planting index that works best in this environment. The larger the plant's leaves, the more protection they will provide from the sun and the higher the yield will be. In addition, to evaluate the effectiveness of the roof energy system, four height dimensions of 8, 13, 18, and 23 cm were considered for the cultivation layer. According to the findings, the height of the plant substrate layer is 23 cm, and the height of the cultivation layer is 18 cm. The cultivation layer that yields the best results for green roofs in this environment.
In the context of evolving a circular economy for the palm-oil industry, this article presents a study of oil-palm empty fruit bunch (EFB) conversion and utilization within a palm-oil mill. Pilot-scale hydrothermal carbonization (HTC), washing and gasification processes, as well as anaerobic digestion of the HTC liquid product were investigated. Results showed that the fuel properties of hydrochars had improved. In terms of air gasification, char and tar products accounted for 22.7–33.8 % and 17.3–28.8 %, respectively while CO2/O2 gasification resulted in 31.3–36.6 % for char and 8.5–30.8 % for tar. In general, hydrochar (HT-EFB) gave the lower tar content compared to washed hydrochar (HTW-EFB) due to the catalytic effects of alkali and alkaline earth metals. Major tar components from HT-EFB and HTW-EFB were aliphatic and monoaromatic hydrocarbons, respectively. Syngas products from air gasification of hydrochars were 39.9–56.5 %, 11.4–21.4 %, and 9.0–14.4 % for CO, H2 and CH4, respectively while CO2/O2 gasification products yielded 45.1–56.6 %, 11.6–24.3 %, and 9.4–14.0 % for CO, H2 and CH4, respectively. The lower heating value of syngas was in the range of 4.7–6.6 MJ/Nm³ and cold gas efficiency was approximately 39.1–55.1 %. The cumulative methane from the liquid products amounted to 213.8 and 154.5 L/kg COD for food/microorganism ratios of 1:2 and 1:3, respectively. The mass and energy balance showed that the whole process is promising for future commercialization.
Iron (Fe) migration mechanisms and hydrochar properties in dyeing sludge hydrothermal carbonization (HTC) are important topics in wastewater treatment. HTC treatment of sludge produces wastewater containing Fe so it is necessary to study the migration behavior of Fe during HTC treatment. This study investigated the basic properties and Fe migration behavior of hydrochar during HTC treatment supplemented with nitric acid (HNO3). The results showed that the carbonization degree and yield of hydrochar treated with the HNO3 solution (HHC) were much lower than those of hydrochar treated with ultrapure water (WHC). The variation of total Fe (TF) concentration indicated that the decomposition of organic material and dissolution of minerals in the aqueous release of Fe during the liquid phase, led to much lower TF concentrations compared to the original dyeing sludge. Fe release was further enhanced with the addition of HNO3 and increase of temperature, rendering a much lower TF concentration of the HHC compared to the WHC. The variations of Fe³⁺ and Fe²⁺ concentrations indicated that the HTC-treated hydrochar contained more Fe²⁺, caused by Fe³⁺ reduction with hydroxyl methyl-furfural and glucose in the liquid and subsequent Fe²⁺/Fe³⁺ transferral to the solid hydrochar phase. X-ray diffraction (XRD) showed that the main Fe content in WHC was FeO(OH), while HHC contained mainly Fe(SO4)(OH)•2H2O and Fe3O4. XPS and XRF showed that Fe could more easily enter the internal pores of the hydrochar instead of being deposited on the surface. This study provided more insights on Fe migration behavior during HTC treatment.
Context Identifying non-functional requirements (NFRs) and their categories at the early phase is crucial for analysts to design software systems and recognize constraints. Automatic non-functional requirements classification methods have been studied for reducing the costs of that labor-intensive task. Our previous study focused on the differences among vectorization methods that converted requirements written in natural language into numerical vectors for classification. It had some limitations regarding the number of datasets used, the types of vectorization methods supporting pre-trained data, and the performance evaluation procedure. Objective To examine whether different vectorization methods lead to differences in the classification performance of NFRs and their categories with extended settings. Methods Comparative experiments were conducted with five open data. Nine vectorization methods, including ones with pre-trained data and four supervised classification methods, were supplied. Performance was evaluated with AUC and Scott-Knott ESD test. Results Some advanced methods could achieve better performance than traditional ones when combined with some classifiers. The use of pre-trained data was useful for some categories. Conclusion It is beneficial to consider using some combinations of vectorization methods and classifiers for classifying non-functional requirements categories.
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14,073 members
Savitree Limtong
  • Department of Microbiology
Panuwat Suppakul
  • Department of Packaging and Materials Technology
Ratchanee Hongprayoon
  • Plant Pathology
Arinthip Thamchaipenet
  • Department of Genetics
Apichart Vanavichit
  • Rice Science Center
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Bangkok, Thailand
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http://flas.kps.ku.ac.th/