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Item Nonlocal neumann boundary value problem for fractional symmetric hahn integrodifference equations(MDPI, 2021) Thongchai Dumrongpokaphan; Nichaphat Patanarapeelert; Thanin Sitthiwirattham; N. Patanarapeelert; Mathematics Department, Faculty of Science and Technology, Suan Dusit University, Bangkok, 10300, Thailand; email: nichaphat.p@sci.kmutnb.ac.th; T. Sitthiwirattham; Department of Mathematics, Faculty of Applied Science, King MongkutÕs University of Technology North Bangkok, Bangkok, 10800, Thailand; email: thanin_sit@dusit.ac.thIn this article, we present a nonlocal Neumann boundary value problems for separate sequential fractional symmetric Hahn integrodifference equation. The problem contains five fractional symmetric Hahn difference operators and one fractional symmetric Hahn integral of different orders. We employ Banach fixed point theorem and SchauderÕs fixed point theorem to study the existence results of the problem. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Item Effects of Nutrient Supplement and Chitosan on Microbial Population Change in Up-Flow-Anaerobic-Sludge-Blanket Reactor during Biogas Production(Research and Development Institute Suan Dusit University, 2021) Rungroj Piyaphanuwat; Srisuda Samaimai; Vassanasak Limkhuansuwan; V. Limkhuansuwan; Faculty of Science and Technology, Suan Dusit University, Bangkok, 10700, Thailand; email: vassanasak_lim@dusit.ac.thThe objective of this research was to study the effects of nutrient supplement and chitosan on microbial change in an up-flow-anaerobic-sludge-blanket (UASB) reactor during biogas production. Three UASB reactors were operational in this study. All reactors were operated by feeding dilute stillage with chemical oxygen demand (COD) concentration at 10,000 mg/L and 9 days of hydraulic retention time (HRT) under anaerobic conditions. Reactor 2 and reactor 3 were supplemented with nutrient supplement and chitosan, respectively. The results of the environment and pH values of all UASB reactors showed similar conditions with total volatile acid/ alkalinity (TVA/Alk) values of 0.27-0.31. The COD removal efficiency of reactor 1 (stillage), 2 (stillage and nutrient supplement) and 3 (stillage and chitosan) showed about 79%, 84% and 87%, respectively. In addition, it was found that the UASB reactors supplemented with nutrient supplement or chitosan produced higher levels of biogas than those without additives. The 16S rRNA technique by PCR reaction showed that the dominant archaea in the final fermentation of all UASB reactors and in inoculum sample were hydrogenotrophic (genus Methanobacterium) and acetotrophic methanogens (genus Methanosaeta). The methanogens population in the reactor supplemented with chitosan (18.11%) produced more biogas than the ones in the reactor supplemented with nutrient supplement (14.44%) and in the control reactor (15.95%). © 2021, Research and Development Institute Suan Dusit University. All rights reserved.Item An Investigation of the Language used on Signage in Japanese Town on Sukhumvit Road, Bangkok through the Lens of Linguistic Landscape(Research and Development Institute Suan Dusit University, 2021) Gornkrit Meemongkol; Sutsawad Jandum; G. Meemongkol; International College for Sustainability Studies, Srinakharinwirot University, Bangkok, 10110, Thailand; email: gornkrit@g.swu.ac.th;This study investigates the language diversities and Japanese language usage reflected on the signage found in Japanese town on Sukhumvit Road, Bangkok. A qualitative research method was used, with which samples were collected by taking fifty photos of signage along five alleys on Sukhumvit Road with Japanese script appearing on them. The framework of Landry & Bourhis (1997) was employed in this study. The results show that Japanese has an important role in the multilingual area of Sukhumvit Road whereas English was used as the international language. Moreover, Thai language appeared on the signage as the national language but English was still the main language used to communicate with the target customers of various nationalities. It is inferred that most people in the area understand everyday English well. Additionally, the signage of Japanese restaurants was the most prominent and most of them represent Japanese culture. In addition, horizontal text was evident in the system of writing. This may be influenced by the Thai writing system as well as the Western languages. Furthermore, Kanji scripts were the most used on the signage compared to Hiragana and Katakana scripts. Overall, Kanji, as the picture scripts of Japanese language, may convey the meaning of lexical words to readers effectively. © 2021, Research and Development Institute Suan Dusit University. All rights reserved.Item Evaluation of Extraction Methods of Dietary Fiber from Pomelo Juice Byproducts and Particle Size Distribution on the Physicochemical and Functional Properties(Research and Development Institute Suan Dusit University, 2021) Suwanna Pichaiyongvongdee; Tita Foophow; Piyawan Yoodee; Nujira Rasamipaiboon; S. Pichaiyongvongdee; School of Culinary Arts, Suan Dusit University, Bangkok, 10700, Thailand; email: suwanna_pic@dusit.ac.thPomelo (Citrus grandis (L.) Osbeck) is the largest citrus fruit in Thailand, which pomelo juice is commercially produced during the pomelo juice extraction process. After extraction of the juice, the number of by-products that was produced could be a potential source of functional dietary fiber.The objective of this study was to evaluate extraction methods of dietary fiber from pomelo juice byproducts for functional foods and particle size distribution (150, 180, 250 and 425 _m) by pomelo pulp powder (PPP) that was prepared by simply air drying, milling, sieving and grinding. For pomelo pulp dietary fiber powder (PPDFP), the PPP was treated with NaOH and ethanol to remove protein and fat, respectively. After that, analysis of physicochemical and functional properties of PPP and PPDFP found that the PPDFP was richer in total dietary fiber (92.04%), especially insoluble dietary fiber (91.93%). Water holding capacity (WHC) and oil holding capacity (OHC) of PPDFP were higher than those of PPP. Components that can contribute to the bitter flavor of the powders, limonin, naringin and naringenin were considerably reduced in PPDFP, particularly limonin was totally eliminated. Also, the porous structure of PPDFP may facilitate its use in food processing compared to the more sheet-like structure of PPP. The optimum particle size was 150 _m that resulted in powders with increased WHC and OHC. From the above data, it was concluded that the PPDFP was a good source for food dietary fibers that could be used as a functional ingredient in fiber rich food products. © 2021, Research and Development Institute Suan Dusit University. All rights reserved.Item Factors Influencing Thai Tourists' Decision Making to Choose Dvaravati Civilization for Tourist Attractions(Research and Development Institute Suan Dusit University, 2021) Jirat Chuanchom; Nongluck Popichit; Anonnart Tananchat; Wijittra Srisorn; J. Chuanchom; Faculty of Management Sciences, Suan Dusit University, Bangkok, 10300, Thailand; email: chiruchchiruch@hotmail.comThe objective of this research was to study tourist behavior of Dvaravati civilization-based tourist attractions and find ways to develop tourist behavior of Dvaravati civilization-based tourist attractions. The researcher conducted a random survey of 18,361,221 tourists who visited the Dvaravati Civilization-based tourist attractions. The sample group consisted of 400 Thai tourists aged 20-60 years. Statistical tools used in the data analysis included percentage, mean and standard deviation Cronbach's Alpha was used to assess the reliability of the questionnaire scored at 0.980. Multiple regression analysis was also used to test the correlation among the variables. The findings showed overall opinions of tourists toward tourism behavior of Dvaravati civilization-based tourist attractions were at a high level in all aspects. For each aspect, it was found that reputation of tourist attractions was ranked first, followed by rank two asthe beauty of the tourist attractions and third rank was the value of tourism. Whereas tourism services and facilities were ranked the lowest. As for the relationship with the Dvaravati Civilization-based tourist attraction management, it was found that the relationship was at a high level of 0.601, and factors influencing Thai tourists' decision making to choose Dvaravati civilization affects the potential of Dvaravati civilization-based tourist attractions with a 0.05 level of significance level. As a result, the prediction was presented in the Equation: _ = 1.011 + (0.391Rta) + (0.184Bta) + (0.089Vot) + (0.103Tsf). © 2021, Research and Development Institute Suan Dusit University. All rights reserved.Item Pipe jacking tunnel construction crossing the Bang Pakong River(CRC Press/Balkema, 2021) K. Piriyakul; S. Pochalard; E. RungruengThis article presented a case study on a pipe jacking tunneling project crossing underneath the Bang Prakong River in Thailand. This project belonged to the Thailand Irrigation Department and connected between the Klong Phra Ong Chaiya Nuchit and the Bang Pakong River. The technique and process of tunnel construction crossing the river by pipe jacking method were described in details. Moreover, the technique and process of shaft construction technique for jacking pit and receiving pit by sinking method were explained. The jacking pit was collapsed so it was reversed to be the receiving pit. This pit was rebuilt by the steel casing. Then the new jacking pit was improved from the old receiving by the jet grouting method. The jacking force was controlled under 900 Ton. The horizontal deviation was in between ±60 mm and the vertical deviation was in between ±70 mm along the tunnel line. © 2021 ISSMGE, London, UKItem Co-creating a sustainable regional brand from multiple sub-brands: The andaman tourism cluster of Thailand(MDPI AG, 2021) Siwarit Pongsakornrungsilp; Pimlapas Pongsakornrungsilp; Theeranuch Pusaksrikit; Pimmada Wichasin; Vikas Kumar; P. Pongsakornrungsilp; Department of Tourism and Hospitality Industry, School of Management, Walailak University, Nakhon Si Thammarat, 80160, Thailand; email: kpimlapa@wu.ac.thThe purpose of this study was to explore how a regional brand can be co-created among different cities by employing the concept of place branding and brand culture. The Andaman Tourism Cluster of Thailand (ATC) generates the most tourism revenue in Thailand. Developing a regional brand identity can strengthen the competitive advantage of the ATC. Data were collected using multi-method research through questionnaires, projective techniques, and focus group inter-views. Quantitative data were analyzed using descriptive and inferential statistics, while qualitative data were analyzed using thematic analysis. This study also shows that multi-method research contributes to brand management by facilitating collaboration, participation, and brand congruence among stakeholders. Quantitative and qualitative data were synthesized in order to develop the brand identity of the ATC. Focus group interviews were also employed to co-create the regional brand identity as ÔIrresistible AndamanÕ, of which sustainable tourism management is a fundamen-tal aspect. This study demonstrates how multiple sub-brands with different stakeholders can be integrated into a single regional brand. Moreover, stakeholders should focus on internal branding by communicating with all stakeholders to co-create brand congruence. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Item Antioxidant and anti-aging enzyme activities of bioactive compounds isolated from selected Zingiberaceae plants(Kasetsart University, 2021) Rittipun Rungruang; Wittawat Ratanathavorn; Nattaporn Boohuad; Orrapun Selamassakul; Nattapon Kaisangsri; R. Rungruang; Department of Cosmetic Science, Faculty of Science and Technology, Suan Dusit University, Bangkok, 10700, Thailand; email: rittipun_run@dusit.ac.thBioactive compounds and antioxidant and enzyme inhibition activity levels were evaluated for three plants in the Zingiberaceae family in Thailand. Quantification of the phenolic and curcumin contents revealed that the largest component of all extracts was phenolic compounds (213.16-317.64 mg/g extract). The major curcuminoids in Curcuma longa L., Curcuma aromatica Salisb. and Zingiber montanum (J.Koenig) Link ex A.Dietr. were bisdemethoxycurcumin (BDMC; 27.31 mg/g extract), curcumin (16.59 mg/g extract), and curcumin (0.12 mg/g extract), respectively. The extracts from C. longa, C. aromatica and Z. montanum all showed antioxidant activity that was assessed using 1,1-diphenyl-2-picrylhydrazyl radical 2,2-diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl (DPPH¥) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS¥+) radical scavenging assay. In addition, all extracts had copper chelating activity of more than 50%, with the extract from C. longa having the highest chelating activity (76.45%). All extracts from the three plants inhibited tyrosinase and elastase activity with half maximal inhibitory concentration values of 290.33-1,373.68 µg/mL and 69.61-3386.23 µg/mL, respectively. In addition, collagenase inhibition activity was observed in all extracts. The findings from this study showed that extracts from C. longa, C. aromatica and Z. montanum have potential antioxidant activity and can act as anti-tyrosinase, anti-collagenase and anti-elastase agents. The extracts could be further applied in cosmeceuticals as an active ingredient for anti-aging products. © 2021 Elsevier B.V.. All rights reserved.Item Smart Tourism Destinations Influence a TouristÕs Satisfaction and Intention to Revisit(Allied Business Academies, 2021) Pannee Suanpang; Titiya Netwong; Thinnagorn ChunhapataragulSmart Tourism Destinations (STD) are becoming significantly important for providing personalized tourism products and hospitality services via a digital platform to enhance a high-value experience and gain a competitive advantage for business. The objective of this study is to study the impact of smart tourism destinations that affect the revisit intentions during the COVID 19 pandemic in Thailand. Data was collected from 498 samples and a Structural Equation Model (SEM) was adopted. The findings supported the revisiting behavioral intention model which indicated that the overall satisfaction of tourist is reflected in the use of STD. The results found that the use of STD, travel experience, satisfaction, and revisiting intention are positively significant. The perceptions of smart tourism on revisiting intentions are significant. A significant relationship was observed between STD indirectly affecting travel experience (0.954), travel experience directly affecting satisfaction (0.870), satisfaction directly affecting revisiting intention (0.731), travel experience directly affecting revisiting intention (0.281) and finally, travel experience in-directed (0.248). The Relative Chi-square (_2/df) of 1.247 indicates that the model is suitable. The Comparative Fit Index (CFI) is 0.997, the Goodness Fit Index (GFI) is 0.956 and the model based on the research hypothesis is consistent with the empirical data. The Root Mean Square Error of Approximation (RMSEA) is 0.032. © 2021. All Rights Reserved.Item Analysis of a discrete mathematical COVID-19 model(Elsevier B.V., 2021) Thanin Sitthiwirattham; Anwar Zeb; Saowaluck Chasreechai; Zohreh Eskandari; Mouhcine Tilioua; Salih Djilali; S. Djilali; Department of Mathematics, Faculty of Exact Sciences and Computer Science, Hassiba Benbouali University, Chlef, Algeria; email: s.djilali@univ-chlef.dzTo describe the main propagation of the COVID-19 and has to find the control for the rapid spread of this viral disease in real life, in current manuscript a discrete form of the SEIR model is discussed. The main aim of this is to describe the viral disease in simplest way and the basic properties that are related with the nature of curves for susceptible and infected individuals are discussed here. The elementary numerical examples are given by using the real data of India and Algeria. © 2021 The Author(s)Item Quantum Hermite-Hadamard type integral inequalities for convex stochastic processes(American Institute of Mathematical Sciences, 2021) Thanin Sitthiwirattham; Muhammad Aamir Ali; HŸseyin Budak; Saowaluck Chasreechai; M.A. Ali; Jiangsu Key Laboratory for NSLSCS, School of Mathematical Sciences, Nanjing Normal University, Nanjing, 210023, China; email: mahr.muhammad.aamir@gmail.comIn this paper, we introduce the notions of q-mean square integral for stochastic processes and co-ordinated stochastic processes. Furthermore, we establish some new quantum Hermite-Hadamard type inequalities for convex stochastic processes and co-ordinated stochastic processes via newly defined integrals. It is also revealed that the results presented in this research transformed into some already proved results by considering the limits as q; q1; q2 ! 1 in the newly obtained results. © 2021 the Author(s), licensee AIMS Press.Item STEM Education for Developing UndergraduatesÕ 21st Century Skills(Research and Development Institute Suan Dusit University, 2021) Chanisara Metpattarahiran; C. Metpattarahiran; Faculty of Science and Technology, Suan Dusit University, Bangkok, 10300, Thailand; email: chanisara_r@hotmail.comSTEM education is a learning approach that integrates science, technology, engineering, and mathematics with a focus on studentsÕ application of knowledge and technology for solving problem. Engineering design process is included in STEM education with a purpose that students can develop innovation during their collaborative work. STEM education helps students develop skills in critical thinking, communicating, creative thinking, and teamworking. These skills are relevant to those necessary for living in the 21st century. Currently, STEM education is implemented in kindergarten, primary, and secondary levels. In addition, vocational and undergraduate levels start implementing STEM education with a purpose to develop studentsÕ knowledge, skills, and abilities. Teacher plays an important role to transfer knowledge and encourage students to learn. Also, teacher has to motivate students to apply knowledge to solve real-life problems which will be effective for their future career. © 2021, Research and Development Institute Suan Dusit University. All rights reserved.Item On some new trapezoidal type inequalities for twice (P, q) differentiable convex functions in post-quantum calculus(MDPI, 2021) Thanin Sitthiwirattham; Ghulam Murtaza; Muhammad Aamir Ali; Sotiris K. Ntouyas; Muhammad Adeel; Jarunee Soontharanon; T. Sitthiwirattham; Mathematics Department, Faculty of Science and Technology, Suan Dusit University, Bangkok, 10300, Thailand; email: thanin_sit@dusit.ac.thQuantum information theory, an interdisciplinary field that includes computer science, information theory, philosophy, cryptography, and symmetry, has various applications for quantum calculus. Inequalities has a strong association with convex and symmetric convex functions. In this study, first we establish a (p,q)-integral identity involving the second (p,q)-derivative and then we used this result to prove some new trapezoidal type inequalities for twice (p,q)-differentiable convex functions. It is also shown that the newly established results are the refinements of some existing results in the field of integral inequalities. Analytic inequalities of this nature and especially the techniques involved have applications in various areas in which symmetry plays a prominent role. © 2021 by the authors.Item Understanding and assembling user behaviours using features of Moodle data for eLearning usage from performance of course-student weblog(IOP Publishing Ltd, 2021) S. Chayanukro; M. Mahmuddin; H. Husni; S. Chayanukro; Suan Dusit Rajabhat University, Mueang Trang, Trang, 92130, Thailand; email: songsakda@gmail.comIn reality, students learn via eLearning (electronic online learning) system in different ways depending on their learning needs, learning behaviours as well as eLearning system policy for users. However, most learning outcome prediction models of eLearning systems are still not stable and still cannot be applied in many situations as the use of eLearning is considered to be highly dynamic. Therefore, the objective of this work is understand if eLearning system can be predicted based eLearning usage by exploiting Moodle log data. To understand it, features from web log course-student in Moodle is being considered, a number of machine learning techniques also have been applied for benchmarking in this study. The result found that the current group doesn't give better understanding and significant groups of factors that could be able to predict the learning outcome. © Published under licence by IOP Publishing Ltd.Item A qualitative assessment of a full-service network airline sustainable energy management: The case of finnair plc(World Scientific and Engineering Academy and Society, 2021) Glenn Baxter; Panarat Srisaeng; Graham Wild-Airlines are extremely energy intensive. Around the world airlines are increasingly focusing on the environmentally sustainable energy management. Using a qualitative longitudinal case study research approach, this study examines FinnairÕs sustainable energy management over the period 2010 to 2019. The airlineÕs major energy source is jet fuel used for the operation of the airlineÕs aircraft fleet and the electricity which is used to power its facilities located at Helsinki Airport. The study found that FinnairÕs annual jet fuel consumption has grown throughout the study due to the airlineÕs route network and aircraft fleet expansion. The fuel required for ground vehicles has risen reflecting greater operational requirements due to the companyÕs expansion. The annual consumption of electricity and electricity for heating has displayed a general downward trend during the study period. The annual electricity per passenger has also decreased despite the large growth in passenger numbers. Finnair has increased its use of renewable energy sources for its flight and ground operations. A key energy saving strategy has been the acquisition and operation of a modern state-of-the-art, fuel efficient aircraft fleet. © 2021, World Scientific and Engineering Academy and Society. All rights reserved.Item Feasibility of Establishment of the Funds to Support the Ex-offender's Life after Release(International Journal of Criminal Justice Sciences, 2021) Sunee Kanyajit; Suppakorn Poonyarith; Patcharaphan Nakpong; Punnawit Tuppawimol; Wanwipa Muangtham; S. Kanyajit; Mahidol University, Thailand; email: suneekanyajit@gmail.comThis research aimed to investigate the models and purposes of funds to support ex-life offenders after release in foreign countries, develop practicable guidelines for establishing funds to assist or support the ex-life offenders in Thailand, and implement a time-sensitive road map to propel funds. This was qualitative research conducted by searching academic documents for data, reviewing and analyzing features or situations, problems, difficulties, key success factors of aid funds provided in Thailand, and concepts for establishing funds to support the ex-post-release offender's life in Thailand and abroad. The in-depth interview was conducted with one hundred individuals. The focus group consisted of 54 participants. Two seminars were held to solicit feedback and disseminate model proposals or feasible parameters for establishing funds to aid or support life after release. The findings indicated that feasible guidelines for establishing funds to assist or support the ex-life offenders after release in Thailand were intended to enable ex-offenders to reenter society and not re-offend by assisting according to an urgent road map for both adult and juvenile offenders of the Department of Corrections, Department of Juvenile Observation and Protection, and Department of Probation. Moreover, the long-term fund was formed by the draft Royal Decree on establishing the office of fund management for supporting the ex-life offender after release (a public body with direct authority and responsibility) © 2021 International Journal of Criminal Justice Sciences. Under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)Item Antibacterial, antioxidant, cytotoxic effects and GC-MS analysis of mangrove-derived Streptomyces achromogenes TCH4 extract(Institut za Bioloska Istrazivanja, 2021) Janpen Tangjitjaroenkun; Wanchai Pluempanupat; Rungnapa Tangchitcharoenkhul; Waraporn Yahayo; Roongtawan Supabphol; J. Tangjitjaroenkun; Department of Resources and Environment, Faculty of Science at Si Racha, Kasetsart, University, Chonburi, Thailand; email: janpen.ta@ku.th; R. Supabphol; Department of Physiology, Faculty of Medicine, Srinakharinwirot University, Bangkok, Thailand; email: roongtawans@gmail.comThe in vitro biological activities of the ethyl acetate extract of the culture filtrate from Streptomyces achromogenes TCH4 (TCH4 extract) were evaluated. The ethyl acetate extract of TCH4 produced a bacteriostatic effect against Enterobacter cloacae, Staphylococcus aureus, Staphylococcus saprophyticus, Bacillus subtilis, methicillin-resistant S. aureus (MRSA) and Klebsiella pneumoniae. The extract had bactericidal activity against S. aureus, S. saprophyticus, S. aureus (MRSA) and K. pneumoniae with minimum bactericidal concentration (MBC) values in the range of 500-1000 µg/mL. The total phenolic and flavonoid contents in TCH4 extract were 107.20±2.57 mg gallic acid equivalent (GAE)/g and 44.91±0.84 mg quercetin equivalent (QE)/g of dry extract. Antioxidant activity was determined by DPPH radical (IC50 299.64±6.83 µg/mL) and ABTS radical scavenging (IC50 65.53±0.95 _g/mL), and the ferric-reducing antioxidant power (FRAP) (822.76±9.12 mM FeSO4.7H2O/g dry extract) assays. TCH4 extract exhibited cytotoxic activity in the DU-145 cell line (IC50 9.36±0.37 _g/mL). Analysis of extract constituents by GC-MS revealed pyrrolo[1,2-a]pyrazine-1,4-dione, hexahydro-3-(2-methylpropyl) (36.85%), benzeneacetamide (23.76%), and deferoxamine (12.85%) as the major compounds, which have been reported to possess pharmaceutical properties. S. achromogenes TCH4 could be a potential source of bioactive metabolites with antibacterial, antioxidant and anticancer activities for pharmaceutical applications. © 2021 by the Serbian Biological SocietyItem Montgomery identity and Ostrowski-type inequalities via quantum calculus(De Gruyter Open Ltd, 2021) Thanin Sitthiwirattham; Muhammad Aamir Ali; Huseyin Budak; Mujahid Abbas; Saowaluck Chasreechai; M.A. Ali; Jiangsu Key Laboratory for NSLSCS, School of Mathematical Sciences, Nanjing Normal University, Nanjing, 210023, China; email: mahr.muhammad.aamir@gmail.comIn this paper, we prove a quantum version of Montgomery identity and prove some new Ostrowski-type inequalities for convex functions in the setting of quantum calculus. Moreover, we discuss several special cases of newly established inequalities and obtain different new and existing inequalities in the field of integral inequalities. © 2021 Thanin Sitthiwirattham et al., published by De Gruyter.Item Correlating the Speed of Sound with the Gibbs Energy and Estimating the Speed of Sound in Fatty Acid Methyl Ester and Biodiesel(John Wiley and Sons Inc, 2021) Apinya Cheewaphan; Ubol Chuensumran; Suriya Phankosol; Kornkanok Aryusuk; Supathra Lilitchan; Kanit Krisnangkura; K. Krisnangkura; Division of Biochemical Technology, School of Bioresources and Technology, King Mongkut's University of Technology Thonburi (Bangkhuntien), Bangkok, 10150, Thailand; email: kanitkrsnk@yahoo.comThe relationship between the speed of sound (u) in biodiesel and the change in Gibbs energy (_G) has not been described in the literature. With the Gibbs energy additivity method, the relationship between u and _G can be expressed as ln(u2)Ê=Ê_G/RT + A, where R is the universal gas constant, T is the absolute temperature, and A is a constant. The molecule of fatty acid methyl ester (FAME) was arbitrarily sub-divided into groups of atoms and a _G was assigned to each group of atoms. A new model correlating the speed of sound to the structure of fatty acid was derived. The proposed model was good for estimation of the speed of sound in both FAME and biodiesel at various temperatures with good accuracy. The absolute average deviations for the speed of sound in FAME (65 data points) and in biodiesel (175 data points) were 0.23% and 0.36%, respectively. Only the number of double bonds and carbon atoms of the fatty acid are required for the calculation. © 2021 AOCSItem Investigation of the stochastic modeling of covid-19 with environmental noise from the analytical and numerical point of view(MDPI, 2021) Shah Hussain; Elissa Nadia Madi; Hasib Khan; Sina Etemad; Shahram Rezapour; Thanin Sitthiwirattham; Nichaphat Patanarapeelert; S. Rezapour; Department of Mathematics, Azarbaijan Shahid Madani University, Tabriz, 53751-71379, Iran; email: sh.rezapour@azaruniv.ac.ir; T. Sitthiwirattham; Mathematics Department, Faculty of Science and Technology, Suan Dusit University, Bangkok, 10300, Thailand; email: thanin_sit@dusit.ac.th; N. Patanarapeelert; Department of Mathematics, Faculty of Applied Science, King MongkutÕs University of Technology North Bangkok, Bangkok, 10800, Thailand; email: nichaphat.p@sci.kmutnb.ac.thIn this article, we propose a novel mathematical model for the spread of COVID-19 involving environmental white noise. The new stochastic model was studied for the existence and persistence of the disease, as well as the extinction of the disease. We noticed that the existence and extinction of the disease are dependent on R0 (the reproduction number). Then, a numerical scheme was developed for the computational analysis of the model; with the existing values of the parameters in the literature, we obtained the related simulations, which gave us more realistic numerical data for the future prediction. The mentioned stochastic model was analyzed for different values of s1, s2 and b1, b2, and both the stochastic and the deterministic models were compared for the future prediction of the spread of COVID-19. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.