Walailak Journal of Science and Technology最新文献_第10页

Simulation of a Water Droplet on Horizontally Smooth Surface Using Quasi-Molecular Modelling 水平光滑表面水滴的准分子模拟

Walailak Journal of Science and Technology Pub Date : 2011-11-16 DOI: 10.2004/WJST.V3I1.154

Sitthichai Kulsri, S. Danworaphong, M. Jaroensutasinee, K. Jaroensutasinee

{"title":"Simulation of a Water Droplet on Horizontally Smooth Surface Using Quasi-Molecular Modelling","authors":"Sitthichai Kulsri, S. Danworaphong, M. Jaroensutasinee, K. Jaroensutasinee","doi":"10.2004/WJST.V3I1.154","DOIUrl":"https://doi.org/10.2004/WJST.V3I1.154","url":null,"abstract":"We developed a method based on quasi-molecular modelling to simulate the fall of water drops. Each quasimolecule was a group of particles that interacted in a fashion entirely analogous to classical Newtonian molecular interactions. When a falling water droplet was simulated at low impact velocity, the droplets moved periodically (i.e. the droplets moved up and down for a certain period, then stopped moving and reached a steady state), spreading and recoiling without splash or break-up. Spreading rates of falling water droplets increased rapidly as time increased until the spreading rate reached its steady state at time t ~ 0.4 s after the impact. The droplet height above the surface decreased as time increased, remained constant after the droplet diameter attained a maximum value and reached its steady state at time t ~ 0.4 s after the impact. When impact velocities were varied by changing the setting of the vertical height (i.e. at 0.25, 1.25 and 6.00 cm), spreading rates increased with increasing impact velocity. However, the droplet height above the surface was not affected by increasing impact velocity.","PeriodicalId":38275,"journal":{"name":"Walailak Journal of Science and Technology","volume":"3 1","pages":"119-130"},"PeriodicalIF":0.0,"publicationDate":"2011-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68184095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Development of a Microwave System for Highly-Efficient Drying of Fish 鱼类高效微波干燥系统的研制

Walailak Journal of Science and Technology Pub Date : 2011-11-16 DOI: 10.2004/WJST.V3I2.140

Yuttapong Pianroj, Pansak Kerdthongmee, M. Nisoa, Priwan Kerdthongmee, Jirapong Galakarn

{"title":"Development of a Microwave System for Highly-Efficient Drying of Fish","authors":"Yuttapong Pianroj, Pansak Kerdthongmee, M. Nisoa, Priwan Kerdthongmee, Jirapong Galakarn","doi":"10.2004/WJST.V3I2.140","DOIUrl":"https://doi.org/10.2004/WJST.V3I2.140","url":null,"abstract":"Dried fish is an important product of Nakhon Si Thammarat province, located in southern Thailand. Fish are conventionally dried using heat from the sun or heat from burning wood as energy sources. These drying methods have problems such as low efficiency and environmental problems. Exploiting the strong electric dipole of the water molecules in the fish, which allows the fish to absorb microwave energy effectively, we have developed a novel microwave heating system for the efficient drying of fish. The system utilizes a high-voltage power supply so that the magnetron can generate a microwave field continuously, and its output power can be adjusted from 0 - 200 W making it very different to commercial microwave oven. The waveguide is designed for effective transmission of microwave fields into the multi-mode heating cavity. The experimental results reveal that heat produced by the microwave system causes evaporation of moisture from the fish making it possible to produce high quality dried fish. The drying process also shows a dependence of fish surface temperature and moisture content on the radiation time and microwave power.","PeriodicalId":38275,"journal":{"name":"Walailak Journal of Science and Technology","volume":"3 1","pages":"237-250"},"PeriodicalIF":0.0,"publicationDate":"2011-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68184685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 8

Decreased Glutathione Peroxidase Activities with Concomitant Increased Oxidized Glutathione Levels among Residents in an Arsenic Contaminated Community of Southern Thailand 泰国南部砷污染社区居民谷胱甘肽过氧化物酶活性降低与氧化谷胱甘肽水平升高

Walailak Journal of Science and Technology Pub Date : 2011-11-15 DOI: 10.2004/WJST.V5I1.113

W. Chunglok

{"title":"Decreased Glutathione Peroxidase Activities with Concomitant Increased Oxidized Glutathione Levels among Residents in an Arsenic Contaminated Community of Southern Thailand","authors":"W. Chunglok","doi":"10.2004/WJST.V5I1.113","DOIUrl":"https://doi.org/10.2004/WJST.V5I1.113","url":null,"abstract":"Glutathione peroxidase (GPx) and glutathione are important antioxidants responsible for the scavenging of reactive oxygen species (ROS). It has been shown that changes in GPx activities and glutathione levels are associated with various diseases including toxic chemical related diseases and cancers. The study aimed to determine the levels of GPx activity and glutathione among residents in Ron Phibun district, an arsenicexposed area. Blood samples were obtained from 32 volunteers in the Thasala group, a nearby nonarsenic-exposed area and 36 residents in the Ron Phibun group. Red cell lysates were subjected to analysis of GPx activity and glutathione. The results showed that GPx activities were significantly decreased among study subjects from Ron Phibun (p < 0.05). Interestingly, oxidized glutathione (GSSG) levels were significantly increased compared with those from Thasala (p < 0.05). Total glutathione and reduced glutathione (GSH) levels were not different among the two groups. Mean values of GPx activities, total glutathione and GSH tended to decrease among high-exposure subjects compared to low-exposure subjects. This was concomitant with a slight increase in GSSG levels among highexposure subjects. The levels of GPx activities and GSSG may be early biomarkers for low levels of oxidative stress in a mining area affected with arsenic poisoning.","PeriodicalId":38275,"journal":{"name":"Walailak Journal of Science and Technology","volume":"5 1","pages":"57-65"},"PeriodicalIF":0.0,"publicationDate":"2011-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68184448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Utilization of a Self Organizing Map as a Tool to Study and Predict the Success of Engineering Students at Walailak University 利用自组织地图作为工具研究和预测瓦拉克大学工科学生的成功

Walailak Journal of Science and Technology Pub Date : 2011-11-15 DOI: 10.2004/WJST.V5I1.117

W. Kurdthongmee

{"title":"Utilization of a Self Organizing Map as a Tool to Study and Predict the Success of Engineering Students at Walailak University","authors":"W. Kurdthongmee","doi":"10.2004/WJST.V5I1.117","DOIUrl":"https://doi.org/10.2004/WJST.V5I1.117","url":null,"abstract":"Many factors have an influence on the success of undergraduate students particularly in engineering programs. Some students have to drop out as a result of obtaining very poor GPA (grade point average) and/or GPAX (accumulated grade point average) after only their first year of studying. It would be helpful for students if they know how their current GPA/GPAX could be improved in order to successfully graduate. In addition, what would be the expected outcome of their study, if their current GPAs of compulsory subjects are not fairly good? In this paper, the Self Organizing Map (SOM) neural network is utilized as a tool to cluster engineering student data into different groups by means of their study results. The results are then used to produce the weight maps. The maps reflect the correlation between GPA/GPAX of the compulsory subjects and the educational status of students. The result from the SOM with some adaptations to its matching phase is also used to create a predictor which is capable of producing a fairly high degree of correctness. The meaningful results are intended to be used as a guideline for students to prepare and improve themselves. In addition, it might be useful for student advisors and counselors to give appropriate advice to students whose GPAX are critically low. This can be accomplished by advising students to register less or withdraw some subjects in order to leverage their GPAX. In addition, some students should be advised to change their field of study if they perform fairly poorly in all compulsory subjects. The approach utilized in this paper is a novel one with respect to this application domain.","PeriodicalId":38275,"journal":{"name":"Walailak Journal of Science and Technology","volume":"5 1","pages":"111-123"},"PeriodicalIF":0.0,"publicationDate":"2011-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68184621","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Drying Strategy of Shrimp using Hot Air Convection and Hybrid Infrared Radiation/Hot Air Convection 热空气对流和红外辐射/热空气对流混合干燥对虾的策略

Walailak Journal of Science and Technology Pub Date : 2011-11-15 DOI: 10.2004/WJST.V5I1.115

S. Tirawanichakul, W. Phatthalung, Y. Tirawanichakul

{"title":"Drying Strategy of Shrimp using Hot Air Convection and Hybrid Infrared Radiation/Hot Air Convection","authors":"S. Tirawanichakul, W. Phatthalung, Y. Tirawanichakul","doi":"10.2004/WJST.V5I1.115","DOIUrl":"https://doi.org/10.2004/WJST.V5I1.115","url":null,"abstract":"The main objective of the research was to study the effect of drying temperatures using infrared irradiation and electric heating convection on dehydration and was to investigate the effect of drying conditions on the quality of the shrimp. Two sizes of fresh shrimp (100 shrimp/kg and 200 shrimp/kg) with initial moisture content of 270 - 350 % dry-basis were dried under various conditions while the final moisture content of dried shrimp was in ranges between 20 and 25 % dry-basis. Hot air flow rates of 1.0 1.2 m/s, drying temperatures of 40 - 90 °C and infrared intensities of 1,785.7 - 3,571.4 W/m 2 were used in these experiments. The experimental results showed that the rate of moisture content transfer of both sizes of shrimps decreased exponentially with drying time while increasing drying temperature significantly affected to the drying kinetics and quality of the shrimps. Effective diffusion coefficients of both shrimps were determined by a diffusion model forming a finite cylindrical shape was in order of 10 -7 m 2 /s and this effective diffusion coefficient value was relatively dependent on the drying temperature compared to the initial moisture content. The quality analysis of dried shrimp using an infrared source and electric heating source found that the redness value (Hunter a-value) of dried samples using hybrid infrared radiation and electric heating had a higher colour uniformity than other drying methods. Additionally, shrinkage and rehydration properties were insignificantly different for all drying strategies (p < 0.05) and drying using infrared radiation had higher drying rates compared to electric heat convection, corresponding to relatively low drying times.","PeriodicalId":38275,"journal":{"name":"Walailak Journal of Science and Technology","volume":"5 1","pages":"77-100"},"PeriodicalIF":0.0,"publicationDate":"2011-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68184525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 22

A Comparison of Two Methods Used for Measuring the Antagonistic Activity of Bacillus Species 两种测定芽孢杆菌拮抗活性方法的比较

Walailak Journal of Science and Technology Pub Date : 2011-11-13 DOI: 10.2004/WJST.V5I2.86

M. Lertcanawanichakul, Songtham Sawangnop

引用次数: 74

An Automatic System for Non-Uniform Brightness Compensation of LED Arrays: Image Processing Routines to Locate LED Centers LED阵列非均匀亮度自动补偿系统:定位LED中心的图像处理程序

Walailak Journal of Science and Technology Pub Date : 2011-11-13 DOI: 10.2004/WJST.V5I2.90

W. Kurdthongmee, Taofik Lamsub

引用次数: 0

Population Dynamics and Stock Assessment of Blue Swimming Crab (Portunus pelagicus Linnaeus, 1758) in the Coastal Area of Trang Province, Thailand 泰国庄府沿海地区青蟹种群动态及种群数量评价

Walailak Journal of Science and Technology Pub Date : 2011-11-08 DOI: 10.2004/WJST.V6I2.59

A. Sawusdee, A. Songrak

{"title":"Population Dynamics and Stock Assessment of Blue Swimming Crab (Portunus pelagicus Linnaeus, 1758) in the Coastal Area of Trang Province, Thailand","authors":"A. Sawusdee, A. Songrak","doi":"10.2004/WJST.V6I2.59","DOIUrl":"https://doi.org/10.2004/WJST.V6I2.59","url":null,"abstract":"The population dynamics and stock assessment of blue swimming crab ( Portunus pelagicus Linnaeus, 1758) in the coastal area of Trang province, Southern Thailand was done through stratified sampling of 7,499 crabs that were caught by crab gill nets and crab traps. The sampling was done from September 2006 to August 2007. The carapace width and weight relationship was measured, including parameters such as asymptotic outer carapace width (OCW a ), curvature (K), asymptotic inner carapace width (ICW a ), total mortality coefficient (Z), natural mortality coefficient (M), fishing mortality coefficient (F), exploitation rate (E), and total stock at first catch (L c ). The maximum sustainable yield (MSY), maximum economic yield (MEY) and total biomass (B) were estimated. Results showed that the asymptotic outer carapace width was 17.30. The asymptotic inner carapace width was 16.70 cm and its curvature was 1.5 per year. The total mortality coefficient was 8.96 per year, natural mortality coefficient was 1.61 per year and fishing mortality coefficient was 7.35 per year. The exploitation rate was 0.82. The total stock of blue swimming crab at first catch at 2.5 - 3.0 cm was 7,895,170 individuals. Results of stock assessment also showed that the maximum sustainable yield was 364.33 tons, maximum economic yield was 25.29 million Baht (1 Baht = US$ 33) and total biomass was 139.83 MT. A 40 % decrease in the level of fishing effort is recommended to ensure sustainability of the blue swimming crab stock.","PeriodicalId":38275,"journal":{"name":"Walailak Journal of Science and Technology","volume":"23 1","pages":"189-202"},"PeriodicalIF":0.0,"publicationDate":"2011-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68184930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 33

Drying Kinetics of Steamed Glutinous Rice with a Free Convective Solar Dryer 自由对流太阳能干燥机对糯米的干燥动力学研究

Walailak Journal of Science and Technology Pub Date : 2011-11-08 DOI: 10.2004/WJST.V6I2.61

Kongdej Limpaiboon, S. Wiriyaumpaiwong

引用次数: 5

Effects of Malate and Yeast Supplementation in Concentrate Containing High Cassava Chip on Rumen Ecology and Digestibility of Nutrients in Beef Cattle 高木薯片精料中添加苹果酸和酵母对肉牛瘤胃生态及营养物质消化率的影响

Walailak Journal of Science and Technology Pub Date : 2011-11-08 DOI: 10.2004/WJST.V6I1.72

S. Khampa, Pala Chaowarat, R. Pilajun, P. Khejornsart, M. Wanapat

{"title":"Effects of Malate and Yeast Supplementation in Concentrate Containing High Cassava Chip on Rumen Ecology and Digestibility of Nutrients in Beef Cattle","authors":"S. Khampa, Pala Chaowarat, R. Pilajun, P. Khejornsart, M. Wanapat","doi":"10.2004/WJST.V6I1.72","DOIUrl":"https://doi.org/10.2004/WJST.V6I1.72","url":null,"abstract":"Four, 1-year old beef cattle were randomly assigned according to a 2 ´ 2 Factorial arrangement in a 4 ´ 4 Latin square design to study supplementation of malate level at 500 and 1,000 g with yeast ( Saccharomyces cerevisiae ) at 1,000 and 2,000 g in concentrate containing high levels of cassava chip. The treatments were as follows: T1 is supplementation of malate at 500 g with yeast at 1,000 g; T2 is supplementation of malate at 500 g with yeast at 2,000 g; T3 is supplementation of malate at 1,000 g with yeast at 1,000 g; T4 is supplementation of malate at 1,000 g with yeast at 2,000 g in concentrate, respectively. The animals were offered the treatment concentrate at 1 % BW of dry matter basis and urea-treated rice straw. The results revealed that rumen fermentation and blood metabolites were similar for all treatments. However, the digestibility of nutrients were significantly different for the diets, especially digestible nutrient intake of crude protein (CP) which was higher for cows fed cassava-based diets with T4 rather than T3, T2 and T1 (74.3, 72.5, 71.1 and 68.9 %, respectively). In addition, the concentration of volatile fatty acid was significantly different especially the concentration of propionic acid which was slightly higher in cattle receiving T4 than T3, T2 and T1 (23.3, 21.9, 20.9 and 18.0 %, respectively). The populations of protozoa and fungal zoospores were significantly different as affected by malate and yeast levels. In conclusion, the combined use of concentrate containing high levels of cassava chip at 70 % DM with malate at 1,000 g and yeast at 2,000 g in concentrate with urea-treated rice straw as a roughage improved rumen fermentation and digestibility of nutrients in beef cattle.","PeriodicalId":38275,"journal":{"name":"Walailak Journal of Science and Technology","volume":"46 1","pages":"49-58"},"PeriodicalIF":0.0,"publicationDate":"2011-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68184743","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1