เสวียน ใจดี* และ ฟองจันทร์ วรรณลุขขี
This paper deals with solving a Diophantine equation in the type of x^2+y^2=z^n by using mainly the unique factorization in the ring of Gaussian integers and some elementary facts in number theory. We have known that such an equation has no any integer solution apart from the trivial one when is an even positive integer greater than , and it has known as the “Pythagorean equation” in the particular case n=2, which can however be completely solved. Our interest here is to naturally focus on the odd positive one and the unknown variable (or x) is especially restricted to be a prime number only. Eventually, it turns out that we are able to give necessary and sufficient conditions for having an integer solution of such an equation in the case n=3.
กาญจนารักษ์ ฤทธิรักษ์ ภาวินี แสนสุข และ ใกล้รุ่ง สามารถ*
The aim of this research is to compare the regression coefficient estimates of linear mixed models on different mechanisms of missing longitudinal data namely missing completely at random (MCAR), missing at random (MAR), and missing not at random (MNAR). In this study, longitudinal data were initially generated where the random error were normally distributed. Then, the comparison was carried out through the simulation study where the missing rates of each mechanism were set to be 10% and 20%, and the sample sizes were 5, 10, 20, and 50 with 5 repeated measures. The simulation process was replicated 1,000 times using R program in which the maximum likelihood estimation was employed. In overall, by considering both pseudo-bias and pseudo-root mean square error (RMSE) we found that this estimation method is suitable only when the data were missing completely at random (MCAR), but not when the data were missing not at random (MNAR), especially in the large sample size.
กิตติศักดิ์ โชติกเดชาเดชาณรงค์* วิมลรัตน์ พจน์ไตรทิพย์ และ วาสนา ประภาเลิศ
Micropropagation of Dendrobium chrysotoxum plantlet by simple plant tissue culture technique were investagated. In vitro plantlets were cultured on Vacin and Went (VW) agar medium compared with various concentrations of 0, 1/5, 2/5, 3/5, 4/5 and full strength Kittisak (2013) agar media, media from hydroponic solutions, associated with 20 g/L sugar, 7 g/L agar and pH was adjusted to 4.9 which were sterilized with 0.5 mL/L Haiter supplementation. They were incubated in 16 h photoperiod and a light intensity of 2,000 lux at 25±2 ºC compared with room temperature for 4 weeks. It was found that shoot high of plantlet cultured on KS medium with room temperature (2.33 cm) higher that VW medium with significantly. Furthermore, leaf length of this treatment (2.83 cm) also higher that all treatments with significantly. Therefore, KS medium can be used as a replacement for VW medium because it had positive effects on plant growth and development, low cost and simple preparation. Furthermore, the result indicated that room temperature promote better growth than in the controlled temperature room. All treatments cultured at room temperature showed 100% root induction. Therefore, room temperature was the cost saving alternative for plant tissue culture.
สุจิตรา ยาหอม* จิตรสุดา กุลวัฒน์ และ เบญจพร บุราณรัตน์
Oroxylum indicum (L.) Kurz is popularly known to have various bioactive compounds such as flavonoids, glycosides, alkaloids, tannins and terpenoids etc. In this study, we investigated the antioxidant activity of 4 crude extracts of O. indicum leaves, obtained using the solvents hexane, ethyl acetate, ethanol and methanol. Antioxidant activities of the extracts were investigated by DPPH and FRAP assays. Total phenolic and flavonoid content were determined by Folin - Ciocalteu and Aluminum chloride colorimetric assays, respectively. The results indicated that the ethanolic extract of O. indicum leaves had the highest antioxidant activities in both DPPH (IC50 0.92±0.2 mg/ml) and FRAP assays (111.91±3.02 Fe2+ mg/g extract), and had the highest total phenolic (121.90±1.70 GAE mg/g extract) and flavonoid content (298.73±14.46 RE mg/g extract). In conclusion, ethanol extract was found to be a good solvent for extraction and having good antioxidant activity in all assays. O. indicum leaves ethanolic extract contains bioactive compounds and have good antioxidant activities that could be studied in other biological activities and may be useful for pharmaceutical products.
ดรุณี มะยูโซ๊ะ นาซีบะห์ หะมิดง และ ปิยะวรรณ์ บุญญานุพงศ์*
Cherry tomatoes are a major source of antioxidant, vitamins and minerals. However various processing methods and digestion system may lead to phytochemical change. Aims of study are to 1) compare antioxidant contents and activities of fresh and processed tomatoes. 2) compare antioxidant contents and activities before and after the in vitro digestion of fresh and processed tomatoes. Fresh cherry tomatoes were processed by hot air drying and freeze drying and then the samples were analyzed total phenolic, flavonoids, lycopene, antioxidant activities (ABTS and O2-) before and after the in vitro digestion. The results showed that total phenolic and lycopene contents were decreased while total flavonoids contents were significantly (p<0.05) increased by processing methods when compared with fresh tomatoes. ABTS radical scavenging activity was significantly increased in processed tomatoes (hot air drying) when compared with fresh tomatoes; however, it was not different to freeze drying tomatoes. Antioxidant activity of O2- in tomatoes was only significantly (p<0.05) decreased after using hot air drying method when compared with fresh tomatoes. After the in vitro digestion, it was found that total phenolic contents were decreased in fresh and processed tomatoes while total flavonoids (only in fresh and freeze drying tomatoes) and lycopene contents were significantly (p<0.05) increased. Radical scavenging activities of ABTS and O2- (except hot air drying tomatoes) were significantly (p<0.05) decreased after the in vitro digestion. Processing of tomatoes result in a lower tendency of antioxidant content and activities when compared with fresh tomatoes. After the in vitro digestion, most of antioxidant contents tend to increase while antioxidant activities tend to decrease compared with those before the in vitro digestion. Therefore, it should be taken into account that the processing methods and in vitro digestion highly effected on the change of antioxidant contents and activities by increasing and decreasing its level.
สุวิมล อุทัยรัศมี* สุธีร์ ดวงใจ และ สุวรรณ ตั้งมิตรเจริญ
The objective of this study was to assess genetic diversity of Dalbergia cochinchinensis in five intensively managed plantations, including Wang Nam Khiao Forestry Research and Student Training Station (WK), Klongtakao Plantation (KK), Tagum Noboru Umeda Plantation (TU), Dong Lan Silvicultural Research Station (DL), and Mu Si Silvicultural Research Station (MS). Leaves of 30 individual trees in each plantation were collected for genetic diversity study using Inter Simple Sequence Repeat (ISSR) markers technique. From total 150 samples, 10 primers were appropriate to yield 76 amplified bands. At species level, the percentage of polymorphic loci (% P), mean expected heterozygosity (He), and the Shannon’s information index of diversity (I) were high (81.58 %, 0.2904, and 0.4336, respectively). Among the investigated of five populations, population from WK contained the highest genetic diversity, followed by population from DL, KK, MS and TU. Unweighted pair group method of arithmetic average (UPGMA) cluster analysis divided the populations into two main groups, which TU was separated from the other 4 plantations (WK, KK, DL and MS). The result of this study confirmed that D. cochinchinensis plantation is one of a good practices to maintain a high level of genetic diversity. Therefore, germplasm collection as seed or scion from various sources (ex situ gene conservation) should be the urgent tasks of the related organizations in order to maintain a high level in genetic diversity.
จารุวรรณ สุพรรณพยัคฆ์ ปาริสุทธิ์ เฉลิมชัยวัฒน์* และ ทัศนีย์ ลิ้มสุวรรณ
Sea lettuce (Ulva rigida), contains an interesting source of nutrients and other health promotion compounds but it can be decomposed easily because of its high moisture content. The objective of this research was to study the effect of drying condition on the quality of sea lettuce and its application in a crispy snack. The hot air drying process was conducted by using 3×2 factorial in CRD on the effect of three different temperatures; 50, 60 and 70 ºC and two different times at 6 and 8 h. The results showed that temperature and time effected on the physical and chemical quality of sea lettuce. The sea lettuce powder obtained from drying condition at 50 ºC for 8 h gave the highest protein and calcium content as 20.60% and 1333.96 mg/100g, respectively. Therefore, the sea lettuce powder from this drying condition was selected to produce a crispy snack. The sea lettuce powder was added to crispy snack at 4, 6 and 8% (by weight of flour). The crispy snack without sea lettuce powder served as the control. The increasing in sea lettuce powder caused an increase in protein and calcium contents. Moreover, there were no significant difference (p>0.05) in sodium chloride content. The sensory evaluation revealed that the addition of 6 % the sea lettuce powder received the highest score of all sensory attributes. The overall liking score was like moderately. The result of this research supported the ideas of using sea lettuce powder to develop nutritious crispy snack with consumer acceptability.
สุทิณา กสิผล* อุทัย ผ่องรัศมี เสนีย์ ศิริไชย และ พิชิต สุดตา
This research aims to test diesel engine performance of 2,500 cc engine volume cylinder size by using diesel and biodiesel: diesel with ratio 5:95, 20:80 and 50:50. Results showed that power engine of biodiesel increases 8.5%. For 50% biodiesel concentration, an average engine power of 99.5 HP, an average wheel power 79.6 HP, an average resistance of the drag power of 18.8 HP at torque 251.7 Nm, and an engine cycles 2,085 rpm. In addition, they also found that the average carbon monoxide incomplete combustion of 0.54 g/km. that lower than that of diesel
ธีรภัทร์ มีบุญ และ อิสสระ ปะทะวัง*
This study is the first report on karyological analysis of the false ornate narrow-mouthed frog, Micryletta inornata. Five males and five females were collected from Chiang Mai University Hariphunchai Education Centre, Lamphun Province. Chromosomes were directly prepared from bone marrow. The cells were harvested by colchicine-hypotonic-fixation-air drying method. Conventional staining was applied to stain the chromosome using Giemsa’s solution. The results showed that the diploid chromosome number was 2n=26, the fundamental number (NF) was 56 in both male and female. The karyotype consisted of 6 large metacentric, 4 large submetacentric, 8 small metacentric and 8 small submetacentric chromosomes. No cytologically distinguishable sex chromosome was observed. The karyotype is as follows: 2n (26) = Lm6+Lsm4+Sm8+Ssm8 .
พัชรนันท์ สุขแสงพนมรุ้ง ปิติพร ฤทธิเรืองเดช* อริสรา หิริโอตัปปะ และ ปิยะมาศ คงแขม
In the instant curry production process, the moisture content of curry paste during stir-frying with oil must be controlled to conserve the authentic flavor. Therefore, the manufacturers require a rapid method, such as near-infrared (NIR) spectroscopy, to determine the moisture content. In this study, the stir-frying of green curry with oil at 90°C was cooked for 3 hours 30 minutes. The stir-fried curry sample was taken every 15 minutes and subsequently scanned with an NIR spectrometer in the range of 950 - 1650 nm at 25°C and then analyzed for moisture content by oven method. Partial least squares (PLS) regression with full-cross validation method was applied to develop the NIR calibration model. A total of ninety samples was randomly selected to be part of the calibration set (N = 70 samples) and validation set (N = 20 samples). The result showed that the moisture content ranged between 14.72 and 53.38%. The NIR spectra region shows the signal peaks at wavelengths of 1210 and 1450 nm which was associated with oil and water, respectively. It is clear that in the 1000 –1450 nm range the absorptivity depends on the amount of water, which was affected by the stir-frying time. With the aids of Standard Normal Variate, a spectral pretreatment method, the PLS model yielded a good prediction of moisture content with correlation coefficient and root mean square error of prediction values of 0.996 and 0.899%, respectively.
นัทธพงศ์ จันทร์หอม และ อรุโณทัย จำปีทอง*
Nowadays, swine farming has been increased, resulting in wastewater discharged into natural waterbodies. Anaerobic digestion process is a conventional method that has been used for treating the wastewater. However, the effluent still has excess nutrients particularly nitrogen and phosphorus that need to be removed before drained. Using plants associated with aeration is an alternative option that may improve water quality. Sesbania sesban (L.) Merr. is a fast-growing species. It can grow in water saturated soil and can absorb nitrogen even at high concentrations (800 mg. L-1), makes this species interesting for use in water treatments. This study aims to evaluate the water treatment efficiency and responses of S. sesban to the anaerobic digester effluent of swine farms. The plants (30 days-old) sown from seeds were measured for their fresh weight, then placed in buckets containing 20 L wastewater. Treatments were divided into 4 treatments (5 replicates) which were i) non-aerated wastewater without plants (control); ii) aerated wastewater without plants; treatments which growing plants combined with iii) aerated and iv) non-aerated wastewater, respectively. Water quality (DO, BOD, TSS, TDS, EC, pH, NH4-N, NO3-N and PO4-P) was analysed every week after begin the experiment until week 6. Then, plant morphology was recorded, and relative growth rates were calculated. Chlorophyll contents and inorganic nitrogen in the plant tissues were analyzed from dry samples. From the study, it was found that aerated wastewater treatments both with and without plants can eliminate NH4-N in the wastewater within 2 weeks, whereas NO3-N concentrations increased. Compared with the treatments of non-aerated wastewater, NH4-N was removed within 3 weeks. DO concentrations increased 26%, 92% and 57% in the treatments of non-aerated wastewater with plants, and aerated wastewater with and without plant, respectively. Moreover, BOD concentrations reduced 34%, 66% and 56% and TSS concentrations reduced 86%, 91% and 90%, respectively in these treatments. Furthermore, the aeration also affects plants. In the aerated treatments, plants had number of leaves, nodule and NO3-N accumulation in the leaves were significantly higher than the plant growing in the non-aerated treatments. While the number of lateral roots, chlorophyll content, NH4-N accumulation in roots and NO3-N accumulation in the stems and roots of the plant growing in the non-aerated treatments were significantly higher than the plant growing in the aerated treatments. Therefore, S. sesban is an interesting species that can be used for treating wastewater from anaerobic digester effluent of livestock activities.
จิราภรณ์ ปุณยวัจน์พรกุล* กชกร มั่งมี และ อรอุมา เมธาเกษร
A high-speed video analysis technique at a rate of 240 frames s-1 and Tracker video analysis software were used to record and study the behavior of wheel and axle system. The motion of the rotating wheel and axle system and hung masses were analyzed. The efficiency of wheel and axle system, coefficient of rotational friction, and the total mechanical energy in the system were investigated. It was found that the efficiency of wheel and axle system was 83.29 % and the coefficient of rotational friction was 1.64×10-4 kg m2s-1. Finally, the total mechanical energy in the system was not conserved during the rolling motion. The total energy lost was caused by the frictional force. From this study, the high-speed video and its analysis can help students and teachers for all levels to visualize simple physics phenomena and relate them to the physics principles learnt in the classroom.
ศุภกานต์ ธิเตจ๊ะ* สุนทร คำยอง อัมรินทร์ บุญตัน พันธุ์ลพ หัตถโกศล และ อริศรา เจริญปัญญาเนตร
This research aims to study land use changes in the right upper Mae Tao watershed situated in Mae Sod district, Tak province, where the largest zinc ore deposit of the country was found. Most watershed area in the past covered by forests, and some subsistence agriculture. Zine mine was taken during 1974 and 2016, and subsequent forest clearing for agriculture resulted in changing proportion of different land use. The present agriculture is mainly economic crops such as fruit trees, vegetables, maize, sugarcane, cassava, etc. The study was divided into 4 periods according to mining: (1) pre-mining (period 1), (2) during mining as before forest plantation (period 2) (3) during mining as after forest plantation (period 3), and (4) post-mining (period 4). The methods included field survey and remote sensing technology for classifying types of land use. The results showed that percentage proportions of natural forest to the lower watershed (MT-2) in the four periods were 73.3, 63.6, 41.4 and 35.9, respectively. Other land use had different values: agricultural land = 25.7, 29.8, 15.9 and 17.2; mine land = 1.0, 6.6, 14.3 and 1.3; and plantation forest = 0, 0, 18.3 and 45.6. Agriculture was changed from for subsistence to commercial purpose. Natural forest was decreased progressively caused by mainly forest clearing for cultivation. Forest plantation in mine land, adjacent degraded forest land and bare forest land taken from the farmers increased the forest area proportion in the watershed, from 73.3% (period 1) to 81.5% (period 4). Local communities conserved the forest by establishing nine community forests. The restoration of Mae Tao watershed is important for developing Mae Sod district as the economic area for trade with Myanmar as the water source for communities and ecotourism, and should be followed the royal initiatives concerning integrated management of King Rama 9.