Suranaree University of Technology
  • Nakhon Ratchasima, Thailand
Recent publications
Friction stir welding (FSW) process was widely used in many industries due to using of aluminium was rising for light-weight design. It was generally known that some grades of aluminium have low melting weldability which might lead to cracks, porosity, warping and deformation, such as 7075 aluminum alloy. The aim of this research was to investigate the effect of FSW parameters on the axial forces and mechanical properties of Aluminium alloy 7075. The three welding parameters were studied, rotation speed, welding speed and stir tool shoulder diameter. The experiment was performed on force measuring fixture with three-axis vertical milling machine. Shoulder diameter was the only main effect that significantly affect to axial force. The minimum axial force was 3205 N with rotational speeds of 1580 rpm, welding speed of 63 mm/min and shoulder diameter 15 mm which gave tensile strength of 325 MPa or 67% of based material. On the other hand, shoulder diameter and welding speed were the main effects which significantly affect tensile strength. The maximum tensile strength was 331 MPa or 68% of base metal with rotational speeds of 1580 rpm, welding speed of 36 mm/min and shoulder diameter 9 mm.
The manufacturing industry, aluminum alloys were used in various applications such as the electric vehicle industry, marine industry, and also aircraft industry. However, welding on some grades of aluminum alloys, for instant Al5083, might lead to problems at weldment such as crack, pinholes, or incomplete weld joint. Friction stir welding was one of solid-state welding which might suit for such aluminum alloys. Therefore, this research was aimed to investigate mechanical properties of weldment on aluminum alloy 5083 welded by friction stir welding. Small friction stir welding machine was applied in this study. Two-factor of the welding parameters, rotation speed, and welding speed, were studied. The rotation speed of three levels (1200, 1500, 1800 rpm), and two levels of welding speed (30 and 60 mm/min) were employed. It was found that rotation speed of 1800 rpm and welding speed of 30 mm/min was found to yield good weldment and maximum tensile strength 224.41 MPa or 68.65% of based material.
Metal–organic frameworks (MOFs) MIL-100 (Cr, Fe) synthesized by the hydrothermal method were subjected to heat treatment under an H2 flow. The MIL-100 (Cr) samples had specific surface areas and pore volumes approximately-two times higher than those of the MIL-100 (Fe) samples. The H2 heat treatment enhanced the crystallinity, especially for MIL-100 (Fe). The resulting adsorbents exhibited a superior CO2 adsorption capacity. Furthermore, the grand canonical Monte Carlo method was used to examine the adsorption mechanism at a molecular level. The heat contribution of each atom type of MOFs was demonstrated. The highest heat was found at low loadings (Henry’s law region) among other regions owing to CO2 adsorption inside the supertetrahedron. The most active atoms were C atoms (CO > CC > CH), followed by the O atom (COunsaturated metal), the unsaturated metal site, the other O atom (COsaturated metal), the saturated metal site, the H atom of the ligands, and the O atom of the metal cluster, respectively. This study can provide insights into the determination of the atomic heat contributions of other adsorbents for a better understanding of material design and the mechanism of adsorption.
The effect of the structural disorder and Ga content variation on the mechanical stability and magnetostrictive properties of the Fe3Ga alloy of structure D03 was studied by density functional theory methods. There are contradictions between experimental data and simulation results for the compound under investigation. Calculations show that, in contrast to the experimental results, the magnetostriction coefficient should be negative. In addition, the energy-strain simulation predicts the mechanical instability of the perfect D03 lattice. Here it is demonstrated that the permutation of Fe and Ga atoms stabilizes the Fe–25Ga structure. However, the sign of the magnetostriction coefficient remains negative. The further structure modification by partially replacing Fe atoms with Ga leads to a change in the sign of the magnetostriction coefficient in agreement with the experiment.
A recent paper considered symmetries and conservation laws of the plane one-dimensional flows for magnetohydrodynamics in the mass Lagrangian coordinates. This paper analyzes the one-dimensional magnetohydrodynamics flows with cylindrical symmetry in the mass Lagrangian coordinates. The medium is assumed inviscid and thermally non-conducting. It is modeled by a polytropic gas. Symmetries and conservation laws are found. The cases of finite and infinite electric conductivity need to be analyzed separately. For finite electric conductivity σ(ρ,p) we perform Lie group classification, which identifies σ(ρ,p) cases with additional symmetries. The conservation laws are found by direct computation. For cases with infinite electric conductivity variational formulations of the equations are considered. Lie group classifications are obtained with the entropy treated as an arbitrary element. A variational formulation allows to use the Noether theorem for computation of conservation laws. The conservation laws obtained for the variational equations are also presented in the original (physical) variables.
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.
As pH-sensitive and hypoxia-responsive probes, three hemicyanine derivatives based on vanillin and the indole ring (Val-Hcys) were synthesized. The fluorescence of the probes can be activated at acidic pH using the amide functionalized sidechains. Furthermore, when Val-Hcys were incubated with hypoxic cells for 5 min, the fluorescent signals significantly increased when compared to normoxia cells (4-fold enhancement, maximum at 180 min). In addition, Val-Hcys tend to accumulate in lysosomes and mitochondria, two important organelles involved in cell mitophagy. Surprisingly, Val-Hcys improved cell viability in hypoxic conditions. As a result, this study demonstrates the utility of Val-Hcys as pH-responsive probes for detecting hypoxic areas.
The accumulation of construction and demolition (C&D) waste in landfills is a global issue which is exacerbated by the impact of rapid urbanization and increased construction activities in metropolitan and regional areas. The recycled sands studied in this research were derived from processed C&D waste from a washing plant located in Melbourne, Victoria. Two types of washed recycled sands were used as the target materials in this study: coarse recycled sand (CRS) and fine recycled sand (FRS). Extensive geotechnical laboratory tests were performed and the results indicated that both washed sand types exhibited similar geotechnical behavior with conventional virgin materials when used as geotechnical fills. Geoenvironmental tests indicated that the application of washed recycled sand will not have adverse impacts on the surrounding environment. This study highlighted CRS and FRS could both successfully substitute quarry materials required for geotechnical fill and subgrade pavement works.
The Vago interferon-like protein participates in the interplay between interferon regulatory factors and the expression of immune-responsive genes. Vago was initially perceived to participate only in the antiviral activation through JAK/STAT pathway. However, certain isoforms of Vago can stimulate antimicrobial responses. Here we identify Vago isoforms in Fenneropenaeus merguiensis (FmVagos) and how they function in antiviral and antibacterial responses against highly invasive pathogens, including white spot syndrome virus (WSSV) and Vibrio parahaemolyticus (VPAHPND). Three isoforms of FmVagos were identified: FmVago4, FmVago5a, and FmVago5b, and expressed throughout tissues of the shrimp. During infection, FmVago4, FmVago5a, and FmVago5b, were up-regulated after WSSV and VPAHPND challenges at certain time points. Pre-injection of purified recombinant FmVago4 (rVago4), FmVago5a (rVago5a), and FmVago5b (rVago5b) proteins could significantly reduce the mortality of shrimp upon WSSV infection, while the increase of survival rate of VPAHPND-infected shrimp was observed only in rVago4 treatment. The immunity routes that FmVagos might instigate in response to the pathogens were examined by qRT-PCR, revealing that the JAK/STAT pathway was activated after introducing rVago4, rVago5a, and rVago5b, while the Toll/IMD pathway and proPO system, combined with PO activity, were provoked only in the rVago4-treated shrimp. Our finding suggests cross-talk between Vago's antiviral and antimicrobial responses in shrimp immunity. These findings complement previous studies in which Vago and its specific isoform could promote viral and bacterial clearance in shrimp.
The measured section of Khlong Muang is composed mainly of polymictic conglomerate, which is a part of an unsystematic sequence of an aluvio-lacustrine environment within the Sam Khaen Conglomerate Member, Huai Hin Lat Formation, Sap Phlu Basin, Nakhon Ratchasima, Thailand. All small-, moderate-, and large-grained conglomerates were recognized, collected, and prepared into grains and matrixes for the total organic carbon (TOC), grain area percentage, rock-forming minerals and elements, micropores, porosity, and tortuosity. The grain area percentages of the small-, moderate-, and large-grained conglomerates were 98.35%, 83.52%, and 72.53%, respectively, and the matrix area percentages were different from 100. The TOC of the grain and matrix ranged from 3.68 to 7.21% that was evaluated to be excellent. Microscopically, the rigid grain rim, attapulgite crystalline, honeycomb structureless, intragranular, microchannel, and microfracture pores were observed. Flocculation and interplatelet pores were only discovered from the matrixes, which were higher in quantitation and size. Almost all the micropores were dominantly generated by the solution and sedimentary alterations associated with burial diagenesis unless the microfractures and microchannels were related to the siliceous-riched beds. They were isolated and suitably formed to be able to store hydrocarbons. The microfractures and microchannels, including the rigid grain rim and honeycomb structureless pores, were interconnected in providing good potential for the migration pathways. Physically, the porosity and tortuosity of the grains were too low (0.39%) and high (0.9619), thus corresponding to the isolated micropores. Moreover, the higher porosity (2.22%) and lower tortuosity (0.6979) of the matrixes conformed to the microfractures, microchannels, rigid grain rim, and honeycomb structureless pores that their pathways and fluid transmission were straighter, especially the large-grained conglomerates. Therefore, the Sam Khaen Conglomerate Member, Huai Hin Lat Formation, provided very good potential for permeability or migration pathways.
The body of knowledge regarding the classification and evolution of freshwater mussels in the family Unionidae (Bivalvia) in Indochina has recently increased. However, the taxonomic revision of all extant taxa in the region is still ongoing. In this study, the genus Pilsbryoconcha was revised based on an integrative analysis of shell morphology, biogeography, and molecular data. Multi-locus phylogeny indicated the availability of eight species within the genus. Four previously recognized species are P. exilis (Lea, 1838), P. schomburgki (Martens, 1860) stat. rev., P. linguaeformis (Morelet, 1875), and P. carinifera (Conrad, 1837), while four other species are described herein as P. acuta sp. nov., P. mekongiana sp. nov., P. kittitati sp. nov., and P. hoikaab sp. nov. In addition, the neotype of P. carinifera is also designated to clarify its long taxonomic ambiguity. Divergent time estimation and historical biogeography analysis revealed that Pilsbryoconcha originated in the area now called the Khorat Plateau around the middle of the Eocene (mean age = 43.12 Mya), before its range was expanded across Indochina through a series of complex geomorphological changes of river systems, which also led to diversification of the genus.
In this work, the wavelet transformation (WT) under the context of convolution neural network (CNN) is developed and applied for breast cancer detection. The main objective is to investigate the effectiveness of the WCNN pooling architecture when compared to other two famous pooling strategies; max and average pooling, particularly targeting at the features extraction and classifying the phases of breast cancer by avoiding the under and overfitting problems. It is discovered in this work that the combination of WT and CNN outperforms the traditional and typical CNNs (with 96.49% of accuracy 95.81% of precision, 96.73% of recall and 96.23% of F measure).
This work aims to numerically investigate the performance of the multiquadric (MQ) radial basis function in more general formats for image reconstruction applications. Desired features, i.e., accuracy and shape parameter sensitivity, of each form is numerically compared and explored. The famous Lena image is damaged using two levels of damage: 20% and 40%, in a Salt-and-Pepper manner. It has been discovered in this work that β=3/2 produces reasonably good accuracy and is least affected by the change in shape parameter while keeping both the CPU time and the condition number reasonably acceptable. This finding is promising and useful for further applications of MQ in more complex contexts.
The purpose of this paper is to propose and study the structure of wavelet transformation (WT) and convolution neural networks (CNN). To get more insights into its effectiveness, three WCNN architectures are designed and tested against one another seeking which model provides the best performance in breast cancer detection using histopathological images. The Breast cancer histopathological database (BreakHis) is used for this task.
Under the architecture of a neural network, this work proposes and applies three multiquadric radial basis function (MQ-RBF) interpolation schemes; The Common Local Radial Basis Function Scheme (CLRBF), The Iterative Local Radial Basis Function Scheme (ILRBF), and The Radius Local Radial Basis Function Scheme (RLRBF). The schemes are designed to perform locally to overcome drawbacks normally encountered when using a global one. The famous Franke function in two dimensions is numerically tackled. It is revealed in this work that all three local methods outperform the traditional MQ interpolation in terms of both CPU-time and condition number, while the accuracy is overall acceptable, particularly when the number of nodes increases. This finding indicates their potential for dealing with bigger datasets and more complex problems.
Biogenic calcium carbonate derived from waste shells has received significant attention in the last 2 decades as a replacement for limestone due to its contribution to reducing environmental impact by turning wastes into value-added biomaterial and moving global society toward net-zero waste. Recently, several review papers have been published regarding applying biogenic derived calcium carbonate in engineering, biomedical, electrochemical, and environmental technologies. This review stands apart from other reviews on this topic in terms of focusing and reviewing the published papers used and reported indirect methods only to obtain calcium carbonate from biogenic waste shells and not by direct methods. The direct or untreated methods include simple grinding, ball milling, or mortar and pestle techniques. In contrast, the indirect methods covered in this review paper consist of precipitation and different chemical treatment techniques. Therefore, this review paper aims to comprehensively summarize the usage of calcium carbonate derived from eggshells and seashells by indirect methods and glance at its recent development for advanced material applications including water treatment, bio-filler, and reinforcement in polymer composites, energy application, pharmaceutical, biomedical, and drug delivery applications.
This study aims to shed light on the association between non-volatile and volatile compounds related to flavor/taste characteristics as well as sensory acceptability of Nile tilapia fillet (Oreochromis niloticus) cooked by various sous-vide (SV) conditions (50–60 ℃, 30–60 min), with fish cooked with boiling water used as control. Higher temperatures and longer processing times of SV cooking led to greater protein and lipid oxidation as indicated by the increase in total sulfhydryl (-SH), carbonyl, free fatty acid (FFA) contents as well as peroxide values (PV) and thiobarbituric acid reactive substance (TBARS) values. The differences in flavor/taste components including adenosine triphosphate (ATP)-related compounds, free amino acids (FAAs) and volatiles were also obtained, which directly affect sensory acceptability as evaluated by using the hedonic scale. Based on principal component analysis (PCA) results, the acceptability score was strongly correlated with inosine monophosphate (IMP) and acetoin, which seem to be the most crucial flavor enhancers for cooked tilapia. Among all samples, tilapia processed at 60 °C for 45 and 60 min, which contained significantly higher IMP and acetoin (p < 0.05) than others, had significantly higher flavor-liking and overall-liking scores, with a more than 7.5 meaning for high acceptability (p < 0.05), indicating the optimal SV conditions for tilapia fillet. Overall, the present finding indicated that the SV-cooking technique, at the optimal conditions, can improve the meat quality of cooked fish, in terms of flavor/taste characteristics, compared with traditional cooking (control).
The aims of this research are: to investigate and develop a multilevel analysis of unsafe actions or risky behaviors; to study the influence of road safety policy factors on risky behaviors; and to analyze personal characteristics that influence risky behaviors. Data were collected using 1,474 samples from locations countrywide at the district level, including 76 clusters, via the Driver Behavior Questionnaire (DBQ) and road safety policy. The results indicate that, for the district-level model, the participation factor directly and negatively influenced risky behaviors, and government support indirectly had a negative impact through participation. Thus, people’s participation in the area caused a decrease in unsafe behaviors. Meanwhile, safety policy support in the area partially caused people to participate at a significant level. At the personal level, income, having a driver’s license, past violations, and past accidents significantly affected risky behaviors, especially having a driver’s license, which had a negative influence. This meant that people who had a driver’s license facilitated a positive effect in terms of decreasing risky behaviors, while people with past violations and past accidents influenced this situation positively. The more traffic law violations and accidents the participants had, the more they engaged in unsafe actions. Based on the findings, acknowledging and solving the problem of unsafe driving at a spatial level can address the issue by supporting different measures to help people in the area improve the situation. In addition, we should assist people who have a driver’s license by offering them useful training to decrease traffic law violations and inform them about accidents.
Institution pages aggregate content on ResearchGate related to an institution. The members listed on this page have self-identified as being affiliated with this institution. Publications listed on this page were identified by our algorithms as relating to this institution. This page was not created or approved by the institution. If you represent an institution and have questions about these pages or wish to report inaccurate content, you can contact us here.
1,243 members
Supakit Rooppakhun
  • School of Mechanical Engineering
Boonruang Marungsri
  • School of Electrical Engineering
Saroj Rujirawat
  • School of Physics
Jatuporn Wittayakun
  • School of Chemistry
James Ketudat Cairns
  • School of Chemistry, Biochemistry
Nakhon Ratchasima, Thailand
Head of institution
Head of Risk Lab at SUT
66 44 22 4315
66 44 22 4315