Recent Science and Technology

Design of a Lidar-Based Safe Braking Distance Warning System for Small Electric Vehicles

Soontorn Odngam — 2024-12-17

This paper presents a braking distance warning system design using LiDAR technology to measure distances when approaching an object. The objective was to study and develop a system for vehicles that provides warnings before a potential collision occurs. The proposed system was designed for installation in small vehicles that lack basic driving assistance systems to detect objects in front of the vehicle. The current research divides the braking distance for testing into four zones: Zone 1 - Safe distance (greater than 700 cm from an object), Zone 2 - Caution distance (250 - 700 cm), Zone 3 - Brake distance (25 - 250 cm) and Zone 4 - Stop distance (less than 25 cm). In order to conduct this study, a prototype vehicle was moving toward an object at a constant speed of 15 km/hr. It was found that when the prototype was positioned 767.67 cm in front of the object, the warning system would display a green light to indicate a safe distance. When the prototype approached the object at a distance of 593 cm, it would indicate a yellow light for a caution distance. Once the vehicle reached the object at a distance of 237.67 cm, a red status indicator for braking distance was shown. Finally, when approaching the object at a distance of 23 cm, the system would initiate a speed reduction with a deceleration of 0.524 m/s2. This investigation showed that the proposed system was able to operate according to the specified conditions with a braking error of 5.77% from the designated distances. The system developed in this work can be applied to larger-sized vehicles to assist in braking or automatically reduce speed, thereby minimizing the occurrence of accidents.

Phytochemical Screening and Study of Cholesterol Esterase Inhibitory Activity of Extracts from Stem of Dipterocarpus intricatus Dyer

Orapun Jaisamut — 2024-12-17

Dipterocarpus intricatus Dyer is a medicinal plant used for relieving muscle soreness (bark) and curing wounds (resin). This study investigates chemical composition and cholesterol esterase inhibitory activity of D.intricatus stem harvested from Phrasaeng District, Surat Thani Province, Thailand. Using chromatographic method and spectroscopic analysis, two known compounds, dipterocarpolic acid (1) and bergenin (2), were isolated and identified as a triterpene and a coumarin, respectively. Cholesterol esterase inhibition activity of dipterocarpolic acid (1) and bergenin (2) at concentration of 1.0 mg/mL was 35.22±1.44%, and 42.01±1.65%, respectively, whereas methanolic extract showed activity of 31.70±1.23% at 5.0 mg/mL, compared to orlistat (99.55±0.53%). Therefore, D. intricatus extracts are another alternative for further studies in herbal medicine and natural product development.

A New Yeast Strain, Nakaseomyces glabratus DL5, Isolated from a Mangrove Forest in Chonburi Province and Its Potential for Lipid Production

Nisarat Sitthisom — 2024-12-17

This research aimed to search for oleaginous yeasts from mangrove forest resources and primarily investigated their potentials for lipid production. Ten of soil and decaying leaf samples from the Nature Education Center for Mangrove Conservation in Chonburi province were collected and used for the isolation of yeasts on Yeast extract peptone dextrose medium. A total of 38 yeast strains were isolated in which 11 yeast isolates (DL1-DL11) and 27 yeast isolates (S1-S27) were obtained from decaying leaf and soil samples, respectively. These yeast isolates were screened for their high lipid accumulation by Nile red fluorescence assay. Of 38 yeast isolates, five isolates, DL5, S7, S8, S10 and S2, showed the possibility of being oleaginous strains. Those five isolates of yeast were selected based on their potentials of lipid accumulation and further visualized for their ability to accumulate intracellular lipid by Sudan Black B staining. Results showed that isolate DL5 obtained from the decaying leaf sample had the most distinct intracellular lipid accumulation in comparison with the other isolates. Identification of isolate DL5 was found to be Nakaseomyces glabratus on the basis of ITS1- 5.8S rDNA - ITS2 sequence. Further investigation of lipid production by N. glabratus DL5 showed that this strain achieved a lipid content of 9.61 ± 2.17 % of dry biomass weight at 120 hours of growth in DMY broth. These results are important preliminary data for further optimization to improve lipid production and accumulation in the yeast for future applications.

Rice (Oryza sativaL.) Seed Quality after Storage in the Humid Tropicsand after Accelerated Aging

Pongsit Chor-unchun — 2024-12-17

Accelerated aging test (AA) has been applied as a technique to evaluate seed vigor and to predict seed storability. This study evaluated the storability and vigor of Sang Yod Phatthalung, Leb Nok Pattani,and Chaing Phatthalung rice seeds by the AA. The seeds were subjected to AA at 42, 44, 46, and 48°C for durations of 48, 72, 96, and 120 h at 100% relative humidity. The seeds were stored in woven plastic bags at room temperature (28±1°C) for 12 months, and were sampled for physical and physiological quality tests every two months. The results showed that Sang Yod Phatthalung, Leb Nok Pattani, and Chaing Phatthalung rice seeds had 94.75-97.25% germination and 9.05-9.98% seed moisture content, and could be stored in the humid tropics for six months with above 80% germination. It suggests that the appropriate AA conditions for the evaluation of rice seed storability in the humid tropics should be done at 46°C for 96 h and 100% relative humidity. This aging regime gave seed vigor separation among varieties with a germination gap of about 10%, while a greater classification (10-30%) occurred after aging at 44°C for 120 h. These AA regimes (46°C for 96 h) serve as a potential tool for predicting the seed storability and classifying rice seeds by their vigor.

Study on Physical and Chemical Quality of Fourfinger Threadfin (Eleutheronema tetradactylum) from Bang Tawa Sub-district,

Phattharawadee Aedtem — 2024-12-17

Bang tawa Sub-district, located in Nong Jik District, Pattani Province, is known as an important fishing ground for "Pla Kulao" (Fourfinger threadfin). The fish caught in this area are primarily processed for salting. However, there is a lack of statistical data on the quantity of Fourfinger threadfins in this area and their post-harvest quality. Hence, this research aims to study the quantity and quality of catches, as well as their storage, during the fishing season. The study revealed that the catch quantity of Fourfinger threadfin in the Bang tawa Sub-district amounted to 8,366.6 kilograms/year. The highest catch quantity was recorded in January, with 2,013.6 kilograms/year. The physical and chemical quality of Fourfinger threadfin with three sizes was studied, and the fish were classified into three weight ranges. Samples were collected every 3 months, namely in January, April, July, and October. The average protein content for each weight range was as follows: 19.97%, 22.79%, 24.35%, and 22.99%, respectively. The 1-2 kilograms Fourfinger threadfin showed the highest protein content in every month (p<0.05). For each weight range, the average fat content was 2.52%, 2.20%, 2.82%, and 2.84%, respectively. Additionally, the fat content in female Fourfinger threadfin was 1.32 times higher than that in males. The TVB-N value, which indicates fish deterioration, had the highest value of 21.51 (mg/100 g)in April. When analyzing the correlation between chemical properties and freshness score of Fourfinger threadfin, it was found that physical characteristics were positively correlated with chemical properties (p<0.01). Regarding the preservation of fresh Fourfinger threadfin for salted fish production, chilling (10±2 °C) allowed preservation for 3 days, whereas freezing (-18±2 °C) extended preservation beyond 30 days.