bluuebunny/crossref_metadata_2025 huggingface dataset:
Role of Global Production Networks on Development of Automotive Industry in selected ASEAN countries
Authors:   , Jongkraijak Wachara
Published: September 2023

This paper investigates the impact of Global Production Networks (GPNs) on the industrial development in 3 aspects; domestic value added, labor productivity, and export performance, employing Trade in Value Added database at the country-sector level from Organization for Economic Cooperation and Development (OECD). The estimation is based on pooled time series, cross section and period fixed effect covering Automotive industry in 4 selected ASEAN countries; Thailand, Indonesia, Malaysia, and Philippines from 1995 to 2016. The results suggest that Thailand can exploit the benefit from GPNs through task specialization and economies of scales, at the same time expanding the domestic capacity. All GPNs involvements make Thailand gain positive value added and productivity, especially through forward linkages. And downstream specialization significantly boosts Thailand’s export performance. Indonesia significantly gains positive value added and productivity through backward linkages in GPNs, while forward linkages boost its export performance. Malaysia significantly lowers value added and productivity from GPNs involvement, which implies the limited domestic capacity to increase the GPNs participation. And though downstream specialization significantly boosts Malaysia's export performance, backward linkages significantly decrease domestic content in gross exports. Lastly, Philippines’ GPNs involvement does not have a significant impact on value added and productivity, and the domestic chains would contribute more to the industrial development. Philippines can increase domestic content in gross exports by producing selected auto parts which they have comparative advantages. As a result, its forward linkages significantly boost gross exports. However, its backward linkages significantly lower its domestic content in gross exports.
Juche realist music : the politicization of music in North Korea
Authors:   , Heo Jungmin
Published: September 2023

In North Korea, music and songs have extensively been used as an effective political tool of state propaganda. Unlike previous research which overlooks the contents of the songs, this thesis examines how their lyrics reflect political ideologies and propaganda operation of North Korean regimes. Their lyrics are analyzed in light of the historical context they were written in and widely perceived. It aims at contributing to the knowledge of North Korean music and its relationship with the politics of the country.

The study analyzes the lyrics of 100 North Korean songs from 4 different sources using qualitative contents analysis. The findings show that, in term of politicization, the songs reflect seven overlapping themes in promoting its authoritative regimes. The themes comprise of raising patriotism, exalting the country and the party, exalting socialism and Juche ideology, exalting the supreme leaders, exalting the army, emphasizing economic advancement, and various topics. Moreover, some of the most widely-used symbols within the lyrics are highlighted. As a result, the study shows not only that strong political themes are often found in the expression of the songs, but also that the lyrics of each song are written as a part of a political campaign and perceived threats in response to changing political and social contexts both internally and internationally.
A study of social change and dining culture in Korean society : the case of Honbap (혼밥)
Authors:   , Somporn Nutnicha
Published: September 2023

The purpose of this study is to understand the social change and dining culture in Korean society by emphasizing in Honbap (혼밥), which means eating alone. In Asian countries as Korean society is a collectivism society which people are strong in-groups for a long time, unlike the Western countries where people are in individualism society. The influence of collectivistic values includes the dining culture in Korean society as eating out. Normally, Korean people usually prefer to eat with friends, family members, colleagues rather than eating alone. Eating alone in public looks strange like an outcast, it is hard to find Korean people eating alone in a restaurant. But nowadays, the prosperity of technology, modernization and westernization affects Korean society, the individualistic values also expand among Korean people through the Western culture and also impact to values and demographic change such as late marriage, low fertility in Korean society. The value change not only affects the social change, but also affects dining culture, and eating alone trend gradually occurs in Korean society.
What is the composition of skill shortages among craft and related trades workers in Thailand.
Authors:   , Chaipairinsiri Chanticha
Published: September 2023

This research aims to examine the causes of skills shortages among craft and related trades workers in Thailand, to identify the main skills shortages in various occupations, and to identify the policy solutions and the types of workers that need to be encouraged.

This thesis thus aims at filling this information gap and testing the consistency of the results by measuring the labour shortages and skills shortages and investigating the policy recommendations that can be successfully implemented. The policy recommendations are focused on improving the efficiency of the labour force of Thailand, particularly through investment in education, which can help to fulfil demand and alleviate shortages, including skills shortages. Furthermore, the development of personal capabilities, as well as on-the-job training and apprenticeships in organisations and departments, will be able to develop the existing labour workforce along with new workers in the future to become a multi-skilled labour force.

The results of the study showed that with regard to the skills and knowledge among craft and related trades workers in Thailand, most of the skills and knowledge can be developed by taking courses or receiving training. However, several of the skills and fields of knowledge may require a long period of time to understand and obtain. Moreover, both the private and public sector should focus on education by concentrating more on vocational education and programmes that are equivalent to higher education.
Expenditure patterns of households receiving remittances in Thailand
Authors:   , Ma Sha
Published: September 2023

This article, through the data of the Statistics Bureau of Thailand in 2007 and 2015, examines whether remittances brought about by economic migration will affect household expenditure patterns. This study includes three expenditure patterns: education expenditure, housing expenditure, food and beverage expenditure. The result shows remittances have no effect on housing expenditures. Families receiving remittances, the non-poor households pay more on education than the poor households. And poor households always have more expenditure on food and beverage than non-poor households.
Effect of temperature on antioxidant enzyme activities and gene expression in sand worm Perinereis quatrefagesi (Grube, 1878)
Authors:   , Suksai Sucharat
Published: September 2023

Polychaetes is one of intertidal animals that face the fluctuations of coastal environment through time. One of important environmental factors to animals is temperature regarding to the fluctuation of temperature in intertidal environment. Human activities could also cause high changes in water temperature by high temperature discharges from urban and industries. Since global warming is still a main issue, an increase of seawater temperature about 3°C could be possible as a prediction. This study aimed to investigate effect of temperature in polychaetes Perinereis quatrefagesi at cellular level, which could be indicated by heat shock response and oxidative stress due to function of basic stress. Responses in the worms at the cellular level were measured using real-time PCR for oxidative stress gene expression and using enzyme assay for protein activities. Different temperatures (27, 29, 31, 33°C) with three replication and different exposure times (0 d, 12 hrs, 1 d, 3 d, 7 d, 14 d, and 28 d) were designed. Results of growth parameters showed a significant change in the final wet weight regarding the different temperature levels. While survival rates and specific growth rates gave a similar pattern with a significant difference at the highest temperature. This growth parameters, therefore, revealed the optimal temperature for culture this species at 29°C, while 27°C and 31°C were also acceptable with regard to the high survival rate. For gene expression, the highest upregulation of hsp70, hsp90, sod, and catalase expressed at 33°C. High rate of upregulation was found at the first 12 hours on all gene, except sod which was non-detectable. An increasing trend of hsp70  with temperatures was a significant difference at the first 12 hours exposure. For enzyme activity, SOD activity showed an increasing trend at the first 12 hours exposure and a decreasing trend at 12 hours later, while the highest peak of SOD activity was found at the end of the experiment for all treatment. The CAT activity demonstrated a significant rise in the first 12 hours. Overall, this study supports the negative effect of high temperatures on aquatic organism in term of significantly low growth parameter and active stress responses; heat shock proteins and antioxidant enzymes, especially at the first 12-24 hours exposure.
Finite integration method using chebyshev polynomials for solving time-dependent linear partial differential equations and linear fractional order differential equations
Authors:   , Saengsiritongchai Arnont
Published: September 2023

In this thesis, we devise numerical algorithms base on the finite integration method (FIM) using Chebyshev polynomial to find numerical solutions of time-dependent linear partial differential equations and linear fractional order differential equations. The results show that for time-dependent linear partial differential equations, our algorithm gives a lot better accuracy than the traditional FIMs. Several examples illustrate that our algorithm for linear fractional order differential equations gives good approximate solution as well.
Covering of objects related to rupert property
Authors:   , Tonpho Pongbunthit
Published: September 2023

One problem related to covering problem is whether one object has Rupert property. An object K in R³ has the Rupert property if a hole could be cut through one copy of K with the same size to permit another copy to pass through it. There are objects in R³ which have Rupert property, such as a cube. But not all of objects in R³ has Rupert property, such as a sphere. It is interesting to check that a given object has Rupert property. In this work, we construct useful lemmas for studying this problem. Furthermore, we apply these lemmas to show that most of the 13 Archimedean solids have Rupert property by numerical optimization.
Generalized symplectic graphs and generalized orthogonal graphs over finite commutative rings
Authors:   , Sirisuk Siripong
Published: September 2023

Let R be a finite commutative ring with identity, n ∈ N and β a bilinear form on Rⁿ. In this dissertation, we count the numbers of free submodules and totally isotropic free submodules of Rⁿ of rank s by using the lifting idea. We define the generalized bilinear form graph whose vertex set is the set of totally isotropic free submodules of Rⁿ of rank s and the adjacency condition is given by some rank conditions. We study this graph when (Rⁿ, β) is a symplectic space and an orthogonal space. We can determine the degree of each vertex of these graphs. If R is a finite local ring, we show that these graphs are arc transitive and obtain their automorphism groups. Finally, we prove that we can decompose the graphs over a finite commutative ring into the tensor products of graphs over finite local rings.
Study of asymmetry configuration effects on plate heat exchanger performance
Authors:   , Chartsiriwattana Pearachad
Published: September 2023

Plate heat exchanger is wildly used in engineering application. Previous studies indicated that flow profile effects to plate heat exchanger overall heat transfer coefficient with various factors that manipulate flow profile. This study aims to observe the effect of manipulation flow by creating non-uniform cross-section area along with the flow by applied asymmetry configuration to plate heat exchanger. The experimental results categorize into two groups. The first group is an asymmetric configuration that enhances the overall heat transfer coefficient by 6.54% compared to symmetric configuration due to promoting heat convection. The other group is an asymmetric configuration that ineffective to overall heat transfer coefficient compared to symmetric configuration.
Reaction mechanisms of substrate and inhibitor with ns2b/ns3 serine protease of zika virus by mm and qm/mm simulations
Authors:   , Nutho Bodee
Published: September 2023

Zika virus (ZIKV) infection has become a public health concern worldwide. The recent epidemiological data have revealed a possible association of ZIKV infection with neurological manifestations in both newborn children and adults. Currently, there is no anti-ZIKV drug or vaccine available for preventing or controlling ZIKV infection. An attractive drug target for ZIKV treatment is NS2B/NS3 serine protease that plays a crucial role to cleave the peptide bond during the viral replication process. Initially, the ZIKV NS2B/NS3 serine protease in complex with four peptide substrates were studied to investigate the binding recognition and protein-substrate interactions using conventional molecular dynamics (MD) simulations. The results indicate that the P1 and P2 positions of the substrate play a major role in binding with the enzyme, while the P3 and P4 positions show a less contribution in binding interaction. Afterwards, the cleavage reaction mechanism for the ZIKV protease with its peptide substrate (TGKRS) was studied by hybrid quantum mechanics/molecular mechanics (QM/MM) approach. QM/MM (PM6/ff14SB) free-energy simulations indicate that proton transfer from S135 to H51 and nucleophilic attack on the substrate by S135 are concerted. Importantly, higher-level QM/MM calculations also support a concerted reaction mechanism for this particular reaction. In addition, QM/MM calculations were performed to determine the inhibition mechanism of the ZIKV protease by a dipeptidyl aldehyde inhibitor (acyl-KR-aldehyde). The results show that the transfer of proton from the catalytic S135 to H51 take places in concert with nucleophilic addition on the aldehyde warhead by S135. The anionic covalent complex between the dipeptidyl aldehyde and the ZIKV protease resembles the tetrahedral intermediate for substrate hydrolysis. Therefore, the computational approaches presented here are helpful for further designing of potent NS2B/NS3 inhibitors.
Development and screening of chalcones against cancer protein targets using in silico and in vitro techniques
Authors:   , Sangpheak Kanyani
Published: September 2023

Targeted cancer therapy has become one of high potential cancer treatments. Human topoisomerase IIα (hTopoIIα) and Epidermal growth factor receptor tyrosine kinase (EGFR-TK) are proteins that play important roles on cell cycle. The hTopoIIα catalyzes the cleavage and rejoining of double-stranded DNA while EGFR function on cell signaling. Thus, the two proteins have been suggested as molecular target for the development of novel cancer therapeutics. A series of 47 chalcone derivatives was screened against hTopoIIα and EGFR-TK by in silico and in vitro techniques. Chalcone 3d showed a high cytotoxicity with IC50 values of 10.8, 3.2 and 21.1 µM against the HT-1376, HeLa and MCF-7 cancer cell lines, respectively, while 1c, 2a, 3e, 4e and 4t exhibited potent compounds against A431 with IC50 values < 10 µM. To confirm the result the inhibition of those chalcone on enzyme assay was obtained. The 3d showed an inhibitory activity against hTopoIIα that was better than the known inhibitor, salvicine. Only three chalcones (1c, 2a and 3e) had an inhibitory activity against EGFR-TK with relative inhibition percentages closed to the approved drug, erlotinib. The binding interaction of potent chalcones complex with hTopoIIα and EGFR-TK were studied using molecular dynamics simulation. The observed 3d/hTopoIIα interactions affirmed that 3d strongly interacts with the ATP binding pocket residues while 1c, 2a and 3e/EGFR-TK were well occupied within the ATP binding site and strongly interacted with the 7 hydrophobic residues including the important hinge region residue M793. From ADMET properties, all six chalcones could be served as a lead compounds for development of hTopoIIα and EGFR-TK inhibitors. The information of drug development can be obtained by quantitative structure-activity relationship (QSAR) techniques. A series of chalcone derivatives against A431 were subjected to QSAR analyses. The MLR equation indicated a good correlation between observed and predicted values with R2 = 0.968. The understanding of the relationship between structures and pharmacological effects and the ligand-protein binding pattern leads to important information for the design of high potential anti-cancer drugs.​
The severity of cryptococcus neoformans infection in Fc gamma receptor IIb deficient mice
Authors:   , Surawut Saowapha
Published: September 2023

Cryptococcus neoformans, an encapsulated yeast commonly infecting the central nervous system, refers to as cryptococcal meningitis or cryptococcosis is commonly found in Thailand. C. neoformans is able to replicate, survive inside host macrophages, evade from the cells and use macrophages as a vehicle to disseminate to the target organs, a mechanism known as Trojan horse. Therefore, the containment of C. neoformans in phagocytic cell is important for host protective immunity. Cryptococcosis is common in immunocompromised host such as in patients with low CD4+ T helper cells in HIV-infection and patients taking immunosuppressive drugs. However, the incidence of cryptococcosis in healthy individual (HIV-uninfected) is increasing. Interestingly, it was reported that dysfunctional FcγRIIb polymorphisms are associated with cryptococcosis susceptibility. FcγRIIb is the only inhibitory receptor among the family of FcγRs. FcγRIIb activation leads to suppress of phagocytic activity and reduces cytokine production. Because macrophage is important immune cells against cryptococcosis, we hypothesized that dysfunctional FcγRIIb may influence cryptococcosis susceptibility through the alteration of macrophages functions. We investigated cryptococcosis in the FcγRIIb-/- mouse. Mortality after intravenous C. neoformans-induced cryptococcosis FcγRIIb-/- mice was higher than in age-matched wild-types. Severe cryptococcosis in the FcγRIIb-/- mice was demonstrated by high fungal burdens in the internal organs with histological cryptococcoma-like lesions and high levels of TNF-α and IL-6, but not IL-10. Interestingly, FcγRIIb-/- macrophages demonstrated more prominent phagocytosis but did not differ in killing activity in vitro or the production of TNF-α, IL-6 and IL-10 levels, compared to wild-type cells. Indeed, in vivo macrophage depletion with liposomal clodronate attenuated the fungal burdens in FcγRIIb-/- mice, but not wild-type mice. Upon transferring to wild-type mice, FcγRIIb-/- macrophages with phagocytosed Cryptococcus resulted in higher fungal burdens than FcγRIIb+/+ macrophages with phagocytosed Cryptococcus. Moreover, the T cell subpopulation analysis and IFN-γ intracellular staining suggested that cryptococcosis severity in FcγRIIb-/- mice did not cause by T helper cell defect. These results support, at least in part, a model whereby, in FcγRIIb-/- mice, enhanced C. neoformans transmigration occurs through infected macrophages. In summary, prominent phagocytosis, with limited effective killing activity, and high pro-inflammatory cytokine production by FcγRIIb-/- macrophages were correlated with more severe cryptococcosis in FcγRIIb-/- mice.  In clinical translation, we propose FcγRIIb loss-of-function- polymorphisms as a new risk factor for cryptococcosis.
Localization of cervical branches of facial nerve innervating platysma bands
Authors:   , Tatsanametin Chalisa
Published: September 2023

The facelift is a traditional surgical procedure to improve the appearance of the neck. However, cervical branch of facial nerve (CN) and retromandibular vein (RMV) injury can occur with scissors or even with a liposuction cannula during dissection. This dissection was performed on 27 hemifaces Thai embalmed cadavers to clarify the detail of CN as it relates to surface landmarks to help surgeons predict the location of CN. Branching point of cervical branch of facial nerve (BP) was frequently on C3 regions (96.67%) and located lateral to anterior border of sternocleidomastoid muscle (SCM) 2cm; along x-axis and the distances above thyroid line estimated 5 cm in distance y. While the cervical terminal branching point of the facial nerve TBP1 and TBP2 frequently supply platysma in C3 regions (73.33%) lateral to the anterior border of the SCM 5 mm; along the x-axis and the distances y above the thyroid line was estimated at a distance of 4 cm. Moreover, TBP3 was frequently found at medial to the anterior border of the SCM 5 mm in distance X. There was estimated at a distance of 4 cm superior to the thyroid line, whereas TBP4 was frequently found at medial to the anterior border of the SCM 1 cm in distance X. There was estimated at a distance of 4 mm inferior to the thyroid line. To summarize our finding, BP and TBP frequently placed on C3 regions. The distance between BP and RMV were greater and more medial to RMV in male than female
Atomic probe tomography and creep deformation studies of highly dynamic metallic systems: copper-zirconium based metallic glass alloys and tin-based alloy
Authors:   , Yipyintum Chetarpa
Published: September 2023

The early crystallization process of a Cu-Zr binary metallic glass was investigated by transmission electron microscopy (TEM) and atomic probe tomography (APT). The microstructural analysis was carried out using different characterization methods to see if the phase separation in different chemical compositions and chemical short-range orders were investigated by applying heat treatment under argon atmosphere in differential scanning calorimetry (DSC) chamber. Such a difference in the atomic arrangement of a given amorphous metallic structure is important, the actual characterization of such small difference is not practically easy. For the reason that there is an effect of the sample preparation method which could lead to a misinterpreted of the observation since it could cause artifacts. The selection of a appropriate sample preparation method is important in direct observation of the artifact-free amorphous microstructure, since Cu-Zr binary metallic glass is promptly oxidized and hydrogenated. By prepared the sample using focus ion beam scanning electron microscope (FIB-SEM) and ion milling, oxide and hydride contamination on the sample could observe. Even the low-energy ion milling with liquid nitrogen cooling without careful measured parameters of TEM and APT could also create oxide and hydride of the alloys.

Creep deformation of Sn-1 wt% Bi was studied and compared by conventional tensile creep and nanoindentation creep. The mechanisms corresponding to creep behavior were demonstrated from the two techniques. The creep equation was able to explain the lapping process parameters. The objective of this study is to understand highly dynamic metallic system such as low melting point alloy and metallic glass alloy. This could be further applied and explained in wide range of applications.
Effect Of Chromium Content On Heat Treatment Behavior And Abrasive Wear Resistance Of Multi-Alloyed White Cast Iron
Authors:   , Opapaiboon Jatupon
Published: September 2023

The effect of Cr content on heat treatment behavior and abrasive wear resistance of multi-alloyed white cast irons with basic composition was investigated. The cast irons with varying Cr content from 3-9% were prepared. The annealed specimens were hardened from 1323K and 1373K austenitizing and then, tempered at 673K to 873K with 50K intervals. The microstructure of each specimen consisted of primary austenite dendrite (γP) and (γ+MC) and (γ+M2C) eutectics in specimens with 3 and 5%Cr. By contrast, (γ+M7C3) eutectic appeared in specimens with 6%Cr and more. The matrix in as-cast state was mostly retained austenite but that in as-hardened specimens composed of precipitated secondary carbide, martensite and retained austenite.

As for heat treatment behavior, hardness in as-hardened state increased to highest value at 5%Cr and subsequently, decreased as Cr content rose. The volume fraction of retained austenite (Vg) displayed similar trend to the hardness. The higher austenitizing temperature contributed to lower the hardness but increase the Vg values. In the tempered state, the hardness showed more or less secondary hardening depending on austenitizing temperature and Cr content. The degree of secondary hardening was greater in the specimen hardened from higher austenitizing temperature. The maximum tempered hardness (HTmax) was obtained at 773K to 798K tempering and high austenitizing temperature offered higher HTmax. The Vg decreased gradually as the tempering temperature was elevated. The Vg value at HTmax was less than 5% in all the specimens. The highest value of HTmax was obtained in 5%Cr specimen regardless of austenitizing temperature.

In order to evaluate the abrasive wear resistance, the as-hardened (As-H), HTmax, lower and higher than HTmax (L-HTmax and H- HTmax) specimens were evaluated using Suga abrasion test and rubber wheel abrasion test. A linear relation between wear loss (Wl) and wear distance (Wd) was obtained in all the specimens. The wear rate (Rw) varied depending on heat treatment condition and Cr content. The lowest Rw value or highest wear resistance was obtained in the As-H specimen followed by HTmax specimen. The highest Rw value or lowest abrasive wear resistance was obtained in L-HTmax or H-HTmax specimen, regardless of Cr content and austenitizing temperature. In both abrasive wear tests, the Rw decreased continuously until 6%Cr and after that, it increased gradually with a rise of Cr content. The high austenitizing temperature provided lower Rw value than low austenitizing temperature in all range of Cr content. The Rw decreased with an increase in hardness. In the region of Vg less than 5%, the Rw values scattered in a wide range depending on the hardness. When the Vg got over 5%, the Rw value decreased continuously increasing of Vg value. The worn surface consisted of grooving, scratching and pitting in all the specimens. The pitting was found in eutectic area while the grooving and scratching were observed in matrix.
Preparation and characterization of nickel based nanocomposite coatings with enhanced mechanical and surface properties
Authors:   , Das Malay
Published: September 2023

Ni-W alloy and Ni-W/diamond monolayer and multilayer composite coatings were prepared by electrodeposition from a Ni-W plating bath with diamond particles suspended into the bath. Ni-W/diamond composite coatings were also prepared with varying amounts of Cobalt sulphate additives. The morphology and the composition of the deposits was investigated by means of SEM and EDS, respectively. The effect of operating conditions and additives on the Ni-W coatings were analyzed. The effect of the plating parameters, composite particle size, multilayer deposits and cobalt additives on microstructure and mechanical properties of the Ni-W/diamond composite coatings was investigated. The electrodeposited Ni-W/diamond deposits reported a maximum hardness of 1207 ± 32 Hv whereas, the maximum hardness reported by the Ni-W alloy coatings was recorded to be less than 750 Hv which underlines the significant impact the diamond particles have on enhancing the hardness of the base Ni-W matrix. The addition of Cobalt sulphate in the plating bath in smaller quantities tends to enhance the hardness and wear resistance of the Ni-W/diamond composite coatings and this trend is reversed as the amount of cobalt sulphate in the plating bath is increased beyond 0.1 g/L.
Comparative study of the accuracy of single tooth implants placed between static and mental computer assisted surgery
Authors:   , Smitkarn Palita
Published: September 2023

Objective: This randomized controlled clinical trial aimed to compared the accuracy of implant position between static and mental Computer Assisted Implant Surgery (CAIS) in single tooth gap.

Materials and methods: 52 patients who received 60 implants in single tooth gap, randomized equally into static or mental CAIS. In static CAIS group, data from CBCT scan and data from intraoral or model scan were utilised for the three dimensional virtual planning implant positioning and desiring of a three dimensional surgical guide in implant planning software. Implant bed preparation and implant insertion were done through the three dimensional surgical guide. Implants in the mental CAIS group were virtually planned in the same software, but surgery was done in freehand manner. After the surgery, postoperative CBCT was superimposed onto preoperative CBCT. Deviation in angle, implant shoulder and apex between planned and final implant positions were measured and compared in the same software. 

Results: In static CAIS group, mean angle deviation, 3D deviation at implant shoulder and implant apex were 3.1 ± 2.3°, 1.0 ± 0.6 mm and 1.3 ± 0.6 mm, respectively. In mental CAIS group, mean angle deviation, 3D deviation at implant shoulder and implant apex were 6.9 ± 4.4°, 1.5 ± 0.7 mm and 2.1 ± 1.0 mm respectively. Statistically significant differences were found in all dimensions between two groups. 

Conclusion: Static CAIS demonstrated higher accuracy of implant positioning compared to the mental CAIS in single tooth gap.
The combined material flow analysis and life cycle assessment for integrated end-of-life of mercury contaminated petroleum waste management
Authors:   , Chongchongprasert Putthita
Published: September 2023

Now a day, the waste management generated by offshore petroleum operation (including drilling and production) located in the Gulf of Thailand seem to be a great challenge. Because of their unique characteristic in terms of hazardous properties, petroleum waste requires particular treatments to reduce potential impacts to the environment and human life. This study, the petroleum waste by their disposal code, and waste code was sorted. The Hg-contaminated petroleum waste flow starting from waste generation towards to final disposal was conducted by Material Flow Analysis (STAN, 2.6.601) and Life Cycle Assessment (SimaPro 8.3.0.0) was conducted as tools for evaluating the environmental impacts. The treatment of Hg-contaminated waste was studied by SimaPro LCA software (SimaPro 8.3.0.0) using ReCiPe mid-point (H) method. The human toxicity (kg 1,4-DB eq) and climate change (kg CO₂ eq) impacts were selected because of human toxic damage and global warming concerns. The functional unit was one kg of Hg-contaminated waste. The treatment option was divided into four methods including storage, fuel blending, recovery unlisted material, and landfill. The combined result showed that Hg-contaminated waste disposed of Hg recovery indicated the benefit contributed to human toxicity (-1,344,704 t 1,4-DB eq) but high negative impact on climate change (34,785 t CO₂ eq). The landfill option indicated the high human toxicity impact (5.647 t 1,4-DB eq).
Novel microemulsion formation by the hydrophilic- lipophilic deviation concept using carboxylate extended surfactants for Eor application
Authors:   , Kumkhuntod Suchawadee
Published: September 2023

The Winsor type III (middle phase) microemulsion formation is widely used for enhanced oil recovery (EOR) application. A novel carboxylate surfactant has been an attractive surfactant for the oil recovery due to high chemical stability in harsh reservoir conditions (i.e., high brine concentration and high temperature). This study aims to formulate the middle phase microemulsion in order to obtain the minimum IFT and high solubilization capacity with binary anionic surfactant system using sodium dioctyl sulfosuccinate (AOT) and carboxylate extended surfactants with varying the polyethylene oxide number (EO = 2, 4 and 6) at three mixing molar ratios of 5:5, 7:3 and 9:1 in heptane, octane, decane, dodecane and hexadecane. The results showed that the decrease in the carboxylate extended surfactant fraction in the mixture significantly decreased the optimal salinity (S*). The S* increased with the increasing number of EO groups. The Hydrophilic-Lipophilic Deviation (HLD) equation was used to estimate the optimal condition, where the determined K and Cc values of the carboxylate extended surfactant were conducted and compared. In addition, the batch adsorption of the carboxylate extended surfactant onto quartz sand surface showed less adsorption capacity compared with other surfactants. The increasing of EO groups decreased the surfactant adsorption. Therefore, the carbox-ylate based extended surfactants could be an appropriate system for preventing the surfactant losses by the adsorption and economic viability of surfactant flooding in EOR application.
Green-house gas storage through enhanced hydrate formation
Authors:   , Absuwan Thiphakorn
Published: September 2023

The CO₂ hydrate formation in the presence of different tetrahydrofuran (THF), sodium dodecyl sulfate (SDS), and methyl ester sulfonate (MES) concentrations was investigated in terms of kinetics and thermodynamics. The formation experiment was conducted in the quiescent condition and close system at 3 MPa and 3 °C. The results showed that the CO₂ hydrates formed in the presence of 10 mol% THF, while it did not form with 5.56 mol% THF. The presence of SDS or MES did not promote the hydrate formation. However, the hydrates formed in the presence of a mixture of SDS or MES with 5.56 mol% THF. The result showed that CO₂ uptake with THF combined with SDS or MES was twice higher than that with 10 mol% THF, whereas THF combined with MES resulted in lower induction time than THF combined with SDS. Conversely, using a mixture of MES or SDS at the critical micelle concentration (CMC) and 5.56 mol% THF did not promote the hydrates formation. Surprisingly, the hydrates can form with the presence of MES or SDS at CMC and 4.5 mol% THF at the same experimental condition.
Preparation of polyurethane and polyisocyanurate foams catalyzed by metal acetate-ammonia complexes
Authors:   , Sukkaneewat Benjatham
Published: September 2023

Metal acetate-ammonia complex solutions, namely Cu(Amm) and Zn(Amm), were synthesized and characterized by UV-visible spectroscopy and MALDI-TOF mass spectrometry. Cu(Amm) and Zn(Amm) were used as homogeneous catalysts for accelerating gelling (urethane formation) and blowing reactions (CO2 generation) of rigid polyurethane (RPUR) and polyisocyanurate (PIR) foams. Potassium octoate solution in diethylene glycol, which was used as a trimerization catalyst, was mixed with Cu(Amm) or Zn(Amm) to give a catalyst mixture which can catalyze gelling, blowing and trimerization reactions for the preparation of PIR foams. The catalytic activity of Cu(Amm) and Zn(Amm) in gelling and blowing reactions was compared to that of N,N-dimethylcyclohexylamine (DMCHA), which is an industrial catalyst, and studied by density functional theory (DFT) method, which revealed that Cu(Amm) and Zn(Amm) were Lewis acid catalysts and could decrease the activation energy, but increase the rate constant of gelling and blowing reactions. Cu(Amm) had higher catalytic activity, while Zn(Amm) had lower catalytic activity than DMCHA. Cu(Amm) gave rigid PUR foams with comparable density, % isocyanate conversion and compression strength to those of DMCHA. PIR foams prepared from the mixtures of potassium octoate solution with Cu(Amm) or Zn(Amm) at isocyanate index of 200 had better compression strength, fire-retarded properties and thermal stability than their relating rigid PUR foams. These PIR foams were the ductile materials which had higher compression strength and did not rupture during the compressing test in comparison to the PIR foam prepared from the mixture of potassium octoate solution with DMCHA.
Polyamine accumulation and responses of mango fruit to postharvest polyamine application
Authors:   , Wonnabussapawich Bussarin
Published: September 2023

Mango (Mangifera indicia L.) is a popular tropical fruit which has a great value in both domestic and international markets. Mango is a climacteric fruit which ethylene production increases dramatically, thus leading to a quick ripening process and a short postharvest life. Polyamines (PAs) have been reported to be involved in fruit ripening. Changes in endogenous free polyamines accumulation were measured in two mango cultivars; ‘Nam Dok Mai No.4’ and ‘Nam Dok Mai Si Tong’. Mangoes were allowed to ripen at 25±1 ºC after harvest. It was found that ‘Nam Dok Mai No.4’ mango exhibited higher ethylene production, respiration rate, soluble solid contents and lower titratable acidity than ‘Nam Dok Mai Si Tong’ mango. During fruit ripening, Putrescine (PUT) content decreased and displayed no significant differences between both cultivars. SPD and SPM contents constitutionally increased and were higher in ‘Nam Dok Mai Si Tong’ mango than ‘Nam Dok Mai No.4’ mango. In addition, ‘Nam Dok Mai No.4’ mango, which had a higher ethylene production and a lower level of PAs showed greater market qualities than ‘Nam Dok Mai Si Tong’, which displayed a lower ethylene production. These results suggested that polyamines, especially spermidine (SPD) played a rejuvenating role and regulated mango fruit ripening. The increase in PAs contents may be related to a delay of mango ripening through the reduction of ethylene production. Application of polyamines after harvest also represents a safe and potentially effective method for improving quality and maintaining shelf life of mango fruit. ‘Nam Dok Mai NO.4’ mango was immerged in 0, 1, 2 and 4 mmol/L PUT for 20 minutes and stored at 14 ℃ for 9 days, then transferred to 25 ℃ for another 9 days. The physiological and chemical changes of treated fruit were measured on days 0, 9, 12, 15, and 18. The results showed the most effective treatment was 2 mmol/L PUT, which significantly reduced ethylene production, respiration rate, weight loss, total soluble solids, and increased titratable acidity. In addition, 2 mmol/L PUT treatment increased fruit firmness, reduced soluble pectin content, polygacturonase and pectin methyl esterase activities during storage period. Moreover, our results revealed that the exogenous application of 2 mmol/L PUT increased superoxide dismutase, catalase, guaiacol peroxidase, ascorbate peroxidase and glutathione reductase activities and total antioxidant activities by DPPH radical scavenging and FRAP during storage. The reduction of ethylene production was correlated with the increase of endogenous PAs after exogenous application of PUT. These findings suggested that postharvest exogenous application of 2 mmol/L PUT can be used as an effective method for prolonging storage life and maintaining the quality of ‘Nam Dok Mai No.4’ mango after harvest.
Production and characterization of cutinase from tropical fungi and application with detergent for stain and fuzz removal from spun polyester fabrics
Authors:   , Sooksai Taweeporn
Published: September 2023

Fungi were isolated from agricultural soil and plant specimens. Twenty three isolates from 44 fungal isolates were found to produce cutinase by using PCL-plate clearing assay and their cutinase activity were investigated. All the cutinase-producing fungi were cultured in liquid mineral medium (LMM) containing PCL or crude cutin extracted from papaya peels, which was a carbon source for cutinase production. Cutinase activity was assayed base on the hydrolysis of paranitrophenyl butarate (p-NPB). It was found that PBURU-T5 gave the highest cutinase activity. The isolate PBURU-T5 was selected for identification based on morphology together with comparative nucleotide sequencing from internal transcribed spacer region of the ribosomal RNA gene (rDNA-ITS) and it was identified as Fusarium falciforme. The optimum conditions for the production of cutinase from F. falciforme PBURU-T5, showed that the culture medium with initial pH at 7.0, incubation temperature 30 °C at 150 rpm with the optimal medium composition consisting of 2.5 g/L cutin extract from papaya peels as a carbon source, 4 g/L peptone as nitrogen source  by harvesting on 4 days of incubation provided the highest cutinase activity of 4±0.15 U/ml. The crude cutinase showed the highest enzyme activity at pH 9.0 and temperature 35 °C. For the detergent application, cutinase enzyme (powder form) from F. falciforme PBURU-T5 was mixed with a commercial detergent and was used for oily stain and pill/fuzz removal from spun-polyester fabrics through laundry. Then, the fabric was measured for color values, analyzed for pilling rate, and tested for weight loss and bursting strength loss. When the weight ratio of detergent: enzyme at 1:0.1 was used for fabric washing, oily stain could be completely removed in one washing cycle while fuzzy hair and pill was removed to the acceptable pilling rate of 3-4 (from pilling rate of 1 before washing) in eight washing cycles. After washing, fabric lost 2.68 % of its weight and 8 % of its bursting strength which was not a big concern for polyester wearers.
PDMS-Silver Nanocomposite For Bendable And Stretchable Conductive Stripes
Authors:   , Suriya Porapak
Published: September 2023

In this research, a simple and low-cost protocol for fabricating PDMS-silver composite as flexible conductive polymer is presented. Rod-shaped silver acetate (RS-AcOAg) was synthesized and fabricated into a solvent-cast RS-AcOAg film. The film was thermally decomposed into porous silver structures at 300ºC. The thermal decomposition of RS-AcOAg film induced the formation of silver microparticles (AgNPs) on the surface of RS-AcOAg with the expense of RS-AcOAg rod. AgNPs sintered into bigger particles and turned RS-AcOAg film into porous silver film consisting of interconnected quasi-sphere silver microparticles (AgMPs). The sintered structures transformed porous silver into rigid structures and affected the electrical resistivity due to the cracked structures when mechanical strain was applied. To suppress the sintering of the AgMPs, polydimethylsiloxane base (bPDMS) was coated on the surface of RS-AcOAg before the thermal decomposition. The bPDMS decreased mobility of AgMPs and suppressed the sintering. The porous silver film with and without bPDMS-suppressed sintering consisted of AgMPs with particle size of ~240 nm and ~950 nm, respectively. Commercial columnar silver acetate (CC-AcOAg) was employed for comparison purpose. The porous silver film with bPDMS-suppressed sintering strongly embedded onto the surface of polydimethylsiloxane (PDMS) as PDMS-silver composite, exhibited excellent mechanical properties with high conductivity under mechanical strain, including stretching, bending, and twisting. An application of PDMS-silver composite as a flexible conductive strip to use as strain sensor for robotic hand was demonstrated.
Fabrication of superhydrophobic gold film on polymer substrates
Authors:   , Boonmeewiriya Siriwan
Published: September 2023

Superhydrophobic surface was fabricated by a reduction reaction between chloroauric acid (HAuCl4) and sodium formate (HCOONa) on polydimethylsiloxane (PDMS) substrate without any further surface modification. This generated gold films with superhydrophobic properties examined by water contact angle (WCA) and contact angle hysteresis measurement. Wettability of the fabricated gold film on PDMS substrate can be controlled by the deposition time which provides the WCA > 160o and it could be up to 164.41o with a contact angle hysteresis of 1.93o when the deposition time was prolonged at least 2 hours. To propose the deposition mechanism, the morphological structure and chemical characters of the gold films at different deposition time was deeply investigated using scanning electron microscope (SEM), Energy Dispersed X-ray spectrometer (EDS), X-ray diffractometer (XRD) and infrared spectrophotometer (IR). The gold films contain two different layers including uniformly spherical particles and the secondary structure. The secondary structure is the key factor to control roughness and hydrophobicity of the gold films. The stability of the gold films was inspected by using water-drop testing. The gold films can be tolerated for 7,200 drops without any loss of hydrophobic properties. The potential applications of using the gold films as magneto-wetting surface and a powerful SERS substrate were demonstrated.
Improved barrier properties of PP/LDPE composite film: effect of montmorillonite and poly (lactic acid)
Authors:   , Mooninta Supornpat
Published: September 2023

In this research, the properties of polypropylene (PP) were improved for single layer film application by incorporating low density polyethylene (LDPE), poly(lactic acid) (PLA) and montmorillonite (MMT). The polymer composites was prepared by melt blending using a twin screw extruder and the film was produced by cast film extruder. The addition of LDPE in PP improved the elongation at break and tear strength.  The PP/LDPE blend at the ratio of 80:20 (w/w) was selected for blending with PLA and MMT and the PP/LDPE/PLA/MMT composite showed the increased tensile modulus while the elongation at break decreased with increasing PLA and MMT contents. The morphological structure of nanocomposite was examined by using X-ray diffraction (XRD) analysis, Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). For the barrier properties, the incorporation of PLA and MMT in PP/LDPE blend tended to decrease the oxygen permeability but increase the water vapor permeability. The 80/20/25/3 PP/LDPE/PLA/MMT composite film exhibited the good balance of mechanical and gas permeability properties and had a potential to be used as a food packaging. Moreover, the PP/LDPE/PLA/MMT composite as a new effective film could yield the decreased tomato loss weight at a low temperature storage (14-20 ºC) rather than PP film.
Identification of crude oils and fuel oils after weathering using biomarkers, pyrogenic index and asphaltenes contents
Authors:   , Thongkorn Hathairat
Published: September 2023

Oil spills have become a global problem. This is one of the serious problems in marine environment. The spills are generally from reservoir zipping, accident or unauthorized drainage. Typically, the spilled oils are fuel oils or crude oils which are difficult to differentiate. After oil spill incident, oils are undergone weathering processes such as evaporation, dissolution, and biodegradation etc., which are main factor of depleting hydrocarbon. This work focuses on the distribution of hydrocarbon and diagnostic ratio of polycyclic aromatic hydrocarbons such as pristane, phytane, phenanthrene, pyrene, chrysene and biomarker in hopane group after weathering processes. Moreover, measuring of Al, Si and asphaltenes contents also study in this research. Five crude oils and four fuel oils were weathered in the sea water for 60 days. All samples were characterized by GC-FID and GCxGC-TOFMS followed NORDTEST methodology. Moreover, all samples were measured for asphaltenes contents and Al, Si contents in order to differentiate the types of oil. The result from weathering simulation showed that weathering had significantly affected the distribution of n-alkanes and generally used diagnostic ratio (pristane/phytane) including Al and Si contents changed seriously. However, pyrogenic index and asphaltenes contents can be used as indicators to differentiate fuel oils and crude oils since both of them are strong anti-weathering.