Thaksin University

The growing reliance on edible oils for biodiesel production raises concerns regarding feedstock availability and cost volatility. Palm stearin (PS), a by-product of palm oil fractionation with reduced demand in food applications, offers an attractive alternative feedstock for biodiesel production. In this study, biodiesel was produced from PS using a continuous deglycerolization reactor (CDR), which removes glycerol during transesterification. The optimal process condition was a methanol-oil molar ratio of 5:1, a potassium methoxide (KOCH3) catalyst loading of 1.2 wt%, a mixing speed of 250 rpm and a glycerol removal rate of 0.25 L h-1. Under these conditions, the CDR produced high-quality biodiesel with an ester content of 97.23 wt% and a yield of 98 wt%. An economic assessment indicated a positive net present value, an internal rate of return above 8% per year, and a payback period of 1.12 years. Sensitivity analysis showed that economic performance is influenced by production cost and biodiesel selling price, with a break-even selling price of US$0.99 L-1. The combination of reduced methanol consumption and the use of lower-cost PS support the economic viability of the proposed process.

Flooding is a recurrent climate-related hazard in southern Thailand that frequently disrupts schooling and undermines educational continuity. Despite the critical importance of school-based disaster preparedness, there is limited empirical evidence explaining the drivers of flood preparedness among primary school teachers in climate-vulnerable regions. This study aimed to identify the cognitive, experiential, and topographic factors correlated with flood knowledge, flood risk perception (FRP), and flood preparedness (FP) among primary school teachers in Nakhon Si Thammarat province. A cross-sectional survey was conducted with 745 teachers using a structured questionnaire that covered sociodemographic characteristics, flood experience, training, information sources, and regional topography (elevation, slope, and distance to river). Spearman's rank correlation and Generalized Linear Models (GLMs) were applied to examine the relationships and predictive factors. The findings revealed that topographic factors, specifically distance to the nearest river, were significantly associated with teachers' flood knowledge, while school elevation was significantly related to FRP. Community-based information was a strong predictor of flood knowledge. Furthermore, prior flood experience, first-aid training, access to school-based information networks, and FRP were identified as key drivers of FP. Moreover, the negative relationships were found between flood knowledge and FP suggest that preparedness is influenced by complex cognitive and behavioral mechanisms rather than knowledge alone. These findings highlight the importance of integrating topographic risk information, experiential learning, and community-based information networks into school-based disaster preparedness programs rather than relying solely on knowledge. These findings offer practical implications for designing targeted teacher training and school-based disaster risk reduction (DRR) strategies in climate-vulnerable settings.

Carotenoid biosynthesis in citrus is intricately regulated by developmental cues and environmental stimuli; however, elucidating these regulatory networks in planta remains challenging due to environmental variability. This study employed an in vitro culture system using juice sacs from ‘Siam Red Ruby’ and ‘Benimadoka’ pumelo cultivars to examine the influence of environmental factors on carotenoid metabolism under controlled conditions. Throughout a four-week culture period at 25 °C, the juice sacs exhibited cellular enlargement without callus formation, accompanied by significant changes in carotenoid content and gene expression. Treatment with blue LED light (470 nm peak), 5

This paper introduces a new model selection criterion, SKIC(MLE), for simultaneous equations modelling based on the Kullback information criterion (KIC) using a maximum likelihood estimator (MLE). A comprehensive comparative simulation study demonstrates that when dealing with small sample sizes, SKIC(MLE) outperforms SKIC, a criterion proposed by Keerativibool and Jitthavech (2015). The results indicate that the proposed criterion, SKIC(MLE), has the potential to improve the accuracy of model selection significantly and exhibits higher observed L-2 efficiency than SKIC in such scenarios. The superiority of SKIC(MLE) in small sample sizes is attributed to the fact that the penalty term of SKIC increases exponentially as the number of parameters increases, causing the SKIC value to be higher than SKIC(MLE). As a result, SKIC is more likely to select underfitting models or few parameters than SKIC(MLE). However, this issue is not prevalent in medium to large sample sizes, so SKIC outperforms SKIC(MLE). This research has significant practical implications, potentially revolutionizing simultaneous equations modelling in cases with small sample sizes.

Leafhoppers of the genus Nephotettix (Hemiptera: Cicadellidae) are major vectors of rice tungro disease in Southeast Asia. Despite their economic significance, their evolutionary history, genomic adaptations, and associations with microbial symbionts remain poorly understood. Here, we aim to resolve the phylogenomic placement of Nephotettix, characterize patterns of gene family evolution, assess population connectivity and document the prevalence of bacterial symbionts. Using transcriptomes from 30 species, we reconstructed a robust phylogeny of Cicadellidae, recovering Nephotettix as a strongly supported monophyletic clade in our Cicadellidae phylogeny. Comparative analyses revealed lineage-specific expansions and contractions of gene families, including calcium-binding proteins and membrane-trafficking factors, with several genes showing signatures of positive selection potentially linked to host adaptation. Sequences from individuals sampled across 8 Thai localities indicated shallow haplotype networks and low nucleotide diversity in Nephotettix virescens (Distant 1908) and Nephotettix nigropictus (Stål 1870), patterns consistent with recent expansion or high dispersal. Screening for symbionts revealed universal infections with the obligate symbionts Karelsulcia and Nasuia, while facultative symbionts, Wolbachia and Spiroplasma, occurred at low prevalence across species and sites. This integrative approach refines Nephotettix systematics, identifies candidate genes underlying adaptation, and provides insights into dispersal and symbiont associations. These findings expand genomic resources for rice leafhoppers and offer a framework for improved diagnostics and evidence-based management of tungro disease vectors.