กฤษฎา สิริเพ็ญโสภา และ คำสิงห์ นนเลาพล*
In most undergraduate differential equations textbooks, there are two methods of finding a particular solution for higher-order nonhomogeneous ordinary differential equations that be introduced. The first one is the method of undetermined coefficients. This method can be used to solving differential equations with constant coefficients but it is limited to cases of a right-hand side function. The second one is the method of variation of parameters, which is not limited to cases of a right-hand side function, nor is it limited to differential equations with constant coefficients but it takes longer time and has more processes than the first one. In this paper, we introduce the method of undetermined coefficients to solve some classes of ordinary differential equations with variable coefficients.
กุลภัทร แสนสุข เพชรอาภา บุญเสริม และไตรทศ งามปิติพันธ์*
Quantum mechanics is a theory that can explain phenomena of atom-sized matter or smaller, which classical mechanics cannot do. The central equation of quantum mechanics is the Schrödinger equation. Mathematically, the Schrödinger equation is a second order partial differential equation which tells us how a wave function changes with time. For most problems in quantum mechanics, the Schrödinger equation cannot present exact solutions, except for a few idealized systems in which the Schrödinger equation can be solved exactly. Therefore, approximation methods are needed to find solutions to the Schrödinger equation. In this paper, systems in stationary states are of special interest, in which the Schrödinger equation is reduced to the time-independent Schrödinger equation. One of the approximation methods that work for systems in stationary states is the WKB approximation. In this paper, transmission probabilities for various potentials are calculated using the WKB approximation. The potentials studied in this paper are composed of the asymmetric square-well potential, the hyperbolic tangent potential, the squared hyperbolic secant potential, and the double squared hyperbolic secant potential.
อทิตา เสนาใหญ่* วรพจน์ ล้อมลิ้ม และ สหัช จันทนาอรพินท์
The investigation of bryophytes at Khao Ngon Nak mountain, Hat Noppharat Thara - Mu Ko Phi Phi National Park, Krabi Province, was carried out from March 2018 to October 2019. Bryophyte specimens were collected from various forest types and microhabitats. The life-forms of bryophytes were noted. In total, 145 species 2 subspecies 4 varieties in 55 genera and 19 families of bryophytes were recognized. Among these, 88 species in 31 genera and 9 families were liverworts, while 57 species 2 subspecies 4 varieties in 24 genera and 10 families were mosses. The most common family of liverworts was Lejeuneaceae, whereas Calymperaceae was the richest family of mosses. In addition, Acromastigum echinatum (Gottsche) A. Evans, A. inaequilaterum (Lehm. & Lindenb.) A. Evans, Cololejeunea pseudostipulata Schiffn., Pycnolejeunea cavistipula (Steph.) Mizut. and Riccardia baumannii Hürl. were reported as new recorded species of liverworts for Thailand. In the present study, most bryophytes were corticolous species growing on tree trunks. Five life forms of bryophytes were found, namely: mats, turfs, wefts, cushions and fans. The most common type was mats.
ลักษณา ไชยมงคล* สอลีฮะห์ บังคม และ เศวต ไชยมงคล
This study aimed to determine the appropriate percent reduction of coconut milk used in the formulation of Thai custard in which mung bean was totally replaced by germinated soybean; and to compare the nutritional values of germinated soybean Thai custard in which coconut milk was reduced in the formula with mung bean Thai custard (control recipe). The soybeans (Chiang Mai 60) from Chiang Mai Field Crops Research Center were germinated for 24 hours and then steamed. Cooked germinated soybean was used to totally replace mung bean in the formula. Four Thai custard recipes were prepared, namely germinated soybean Thai custard with 60, 45, or 30% reduced levels of coconut milk and mung bean Thai custard (control recipe). Seven-point hedonic scale was applied in the sensory evaluation by 50 panelists. Proximate compositions and fatty acids profiles were determined. The results showed that germinated soybean Thai custard with 60% coconut milk reduction had comparable overall preference scores to the mung bean Thai custard (5.3+1.4 and 5.3+1.2, respectively; p>0.05). Energy, carbohydrate, protein, fat, and dietary fiber contents in germinated soybean Thai custard (60% coconut milk reduction) were 195.0+14.8 Kcal, 29.74+3.42 g., 7.5+0.2 g, 5.1+0.2 g and 0.81+0.04 g per 100 g, respectively, while mung bean Thai custard had the contents of 210.2+6.6 Kcal, 32.15+1.6 g, 6.3+0.2 g, 6.5+0.3 g, and 0.2+0.06 g per 100 g, in the same order. In conclusion, germinated soybean can totally replace mung bean in making mung bean Thai custard. A sixty percent reduction in coconut milk is acceptable in the germinated soybean Thai custard. Overall preferences had no statistically significant difference from those of the control recipe (p>0.05). The novel formulation has increased protein and dietary fiber contents but lower saturated fatty acids content than the conventional recipe.
ภาวิตา จินตนานฤมิตร ทวีศักดิ์ เตชะเกรียงไกร อำพร แจ่มผล สุนิสา ด้วงนุ่ม ทิวาพร มณีรัตนศุภร และพรทิพย์ พสุกมลเศรษฐ์*
The objective of this study was to develop crispy brownies supplemented with bio-calcium from tuna bones in order to add value of them and study on consumers acceptance. The fortified crispy brownies were prepared by adding 0, 10, 20, 30, 40 and 50 percent of bio-calcium powder which source from tuna bones. The result of sensory analysis found that the 30 percent of calcium fortified crispy brownies obtained the highest liking score. Proximate analysis of 30 percent of calcium fortified crispy brownies from tuna bones contained moisture (2.47 g/100 g), and showed composition of protein (9.47 g/100 g), fat (24.43 g/100 g), ash (5.37 g/100 g), carbohydrate (57.40 g/100 g) calcium (1.37 g/100 g) and phosphorus (0.79 g/100 g). In addition, physical analysis of crispy brownies supplemented with bio-calcium from tuna bones showed that water activity values range from 0.29 to 0.32 and hardness value was 365.45±30.64 N and L* a* b* were 25.20±0.37, 6.45±0.68 and 6.97±0.20, respectively.
วัชรวดี ลิ่มสกุล ธงชัย สุธีรศักดิ์* เสาวลักษณ์ รอดเจริญ และ ปริวรรต วรรณงาม
At present, food preservation film is widely used and most is produced from readymade petrochemical. The food preservation film usually has high tensile and tear strength, and cheap price. However, the film is normally used in a short time, and abandoned as non-biodegradable waste. This research aims to study antibacterial properties of chitosan film blended with organic essential oil from Cinnamomum porrectum for used as food preservation film. The antibacterial properties were studied using 2 types of bacteria, i.e., Staphylococcus aureus and Escherichia coli. The results showed that swelling of the chitosan film decreased, when the concentration of the organic essential oil was increased. Moreover, the addition of organic essential oil from Cinnamomum porrectum resulted in better antibacterial properties of the chitosan film. Nevertheless, only chitosan solution of 2.5 % (W/V) could be fabricated in film form.
งามนิจ นนทโส* และ ธีรศักด์ สมดี
Naturally fermented indigo leaf extract was able to inhibit the growth of Aeromonas hydrophila with a MIC value of 781.25 µg/ml. Indigo leaf extract fermented with the bacterium isolate 7, indigo leaf extract fermented with the bacterium isolate 9 and naturally fermented indigo leaf extract can inhibit the growth of Streptococcus agalactiae with MIC values of 6,250, 1,562.5 and 3,125 µg/ ml and can also inhibit the growth of Bacillus cereus with MIC values of 1,562.5, 1,562.5 and 781.25 µg/ml, respectively. Candida albicans was inhibited by indigo leaf extract fermented with the bacterium isolate 7 and indigo leaf extract fermented with the bacterium isolate 7 with MIC values of 6,250 and 390.63 µg/ml, respectively. The inhibitory zone of B. cereus with naturally fermented indigo leaf extract at concentrations of 15, 30, 60 and 120 mg / ml was 17.3, 17.6, 18.0 and 19.1 mm whereas fermented indigo leaf extract with the bacterium isolate 9 at the same concentrations with B. cereus inhibitory zone of 16.2, 18.4, 19.3 and 22.2 mm. The inhibitory zone of A. hydrophila with naturally fermented indigo leaf extract at the 30, 60, 120 mg / ml was 8.2, 9.6 and 14.2 mm whereas indigo leaf extract fermented with the bacterium isolate 9 at the same concentrations was 9.1, 13.3 and 17.8 mm. The antioxidant properties using ABTS assay of naturally fermented indigo leaf extract was 92.83 ± 0.04 µg TE / g, and indigo leaf extract fermented with the bacterium isolate 9 was 91.58 ± 0.04 µg. TE / g. FTIR Spectra of crude extract of naturally fermented indigo leaves and indigo leaves fermented with the bacteria isolate 9 possess 4 peaks, including 33331.78, 2122.47, 1838.47 and 663.48 cm-1 and 3332.81, 2128.80, 1636.35 and 664.11 cm-1, respectively.
ศรัณย์ ฉวีรักษ์* และ อนัญญา เดชะคำภู
Obesity is the major risk factor for chronic diseases, which are the major health problems globally including Thailand. The previous report has demonstrated that santol (Sandoricum koetjape Merr.) and rambutan (Nephelium lappaceum L.) peel extracts showed to inhibit lipase activity in vitro. However, the experimental prove in vivo is limited. Therefore, this study aims to evaluate the inhibitory effect of both peel extracts on the lipid accumulation in Drosophila melanogaster. The crude extracts was obtained by using the maceration method with 95% ethanol. The extracts were used for testing the gustatory, toxicity and lipid accumulation in Drosophila by mixing in the diet and feeding ad libitum for 7 days. The study groups were divided into 6 group: 1) the control group 2) the high sugar diet group 3-4) the groups that were fed with santol peel extract at the concentrations of 10 and 20 mg/mL mixed with high sugar diet and 5-6), the groups that were fed with rambutan peel extract at the concentrations 10 and 20 mg/mL mixed with high sugar diet. The results showed that the food intake of all groups was not different. The toxicity test results showed that all groups had a survival rate of more than 95%. The lipid accumulation results demonstrated that the mean change in body weight after the experiment, triglyceride content, and fat score in the abdominal area of the Drosophila fed with rambutan extract at the concentration of 20 mg/mL mixed with high sugar diet were significantly lower than other groups. This study's results can be used as a promising data to test in mammal models and to further develop a drug or dietary supplement for inhibition of lipid accumulation.
จันทิมา ชั่งสิริพร* พฤกระยา พงศ์ยี่หล้า และ นิรณา ชัยฤกษ์
Schizophyllum commune contains of ß-glucan named Schizophyllan, which is water soluble polysaccharide with various cosmeceutical properties. The objective of this study is to investigate the optimum condition for ß-glucan extraction. Solvent extraction was done by 65% ethanol and with 45 Hz ultrasonic. Vacuum evaporator was applied for evaporating solvent from the extract. Response surface methodology (RSM) was used in the study of extraction time (X1) 0 – 60 min, ratio of Schizophyllum commune and solvent (X2) 1:5 - 1:20 and the temperature of ultrasonic (X3) 40 – 60oC. The optimum condition inverted that the extraction time, the ratio and the temperature of ultrasonic were 48 min, 1:17 and 45oC, respectively. The analytical results of the extract inverted that ß-glucan content, phenolic content, flavonoid content, and DPPH scavenging activity were 40.48%, 2,701 mg gallic/100 g mushroom, 53.82 mg quercetin/100 g mushroom and 73.16%, respectively. The quadratic model has been accepted as a mathematical model. The significant level of α is equal 0.05, the p-value of the equation model is appropriate. Hence, the regression model derived from the experimental data could describe the correlation among the three independent variables studied and provide the accurate prediction of ß-glucan content from Schizophyllum commune.
Fermented sausage is a meat product made from pork via anaerobic fermentation. From this process may having a pathogenic contamination. The cooking method is grilling in an electric stove. Temperature and time of cooking are affecting on the center-point temperature of sausage, which is the slowest heat transfer position. In this study, thermal diffusivity as 0.35×10-7 m2/s was applied in the heat transfer model. The finite element method was used for heat transfer simulation. Its result was compared with experiment of sausage grilling, which 3 level of temperatures as 120ºC, 140ºC and 160ºC for 3600 – 7200 sec. The result was demonstrated that the simulation of heat transfer to the center point has increased according to an increase in temperature. However, the outcome from this model may not accurate and cannot be used to predict the actual temperature. Therefore, heat transfer models in food are still needed to develop further.
ทัศนพร ราษฎร์เหนือ ปรัชญาภรณ์ ยุขจร ธรรมนูญ ชาญขนิษฐา และ พูนสุข ภูสิมมา*
In this work, the electrical properties of metal-doped ZnO-based varistor materials, prepared by sol-gel method and sintered at 1,150ºC for 2 h, were studied. ZnO-based varistor was doped with addition of 0.1, 0.3 and 0.5 mol% Al(NO3)3. The ZnO-based varistors with additives improved electrical properties. The non-linear coefficient (α) is in the range of 6.7 – 37, the breakdown field (EB) is in the range of 6,298 – 6,496 V/cm, and the leakage current density (JL) is in the range of 45.45 – 614.48 µA/cm2. As a result, ZnO-based varistor with 0.1 mol% Al(NO3)3 exhibited excellent electrical properties with high non-linear coefficient (α = 37) and high breakdown field. The microstructure of ZnO-based varistor consisted of ZnO grain, spinel and Bi-rich phase confirmed by XRD and SEM techniques.
ภากร พุดสวัสดิ์ วิลาศลักษณ์ เอาะน้อย วิชุดา ไชยศิวามงคล* ยุภาพร ตงประสิทธิ์ สุพรรณี อึ้งปัญสัตวงศ์ วรรณพร จันโทภาส ธรรณญพร น้อยพลับ และ ธีรนุช หาญโสภา
The purposes of this research were to develop a prototype system for checking graduation status on web application, a case study of undergraduate curriculums of Department of Statistics, Faculty of Science, Khon Kaen University. This research was a research and development methodology according to the concept of the system development life cycle. The study was divided user into 3 groups: (1) students (2) education service staff (3) teachers and administrators. Currently the university had set up a system to verify graduation on a website. This system could check the total number of credits, and the overall GPAX exceeds 2.00 or not, but it is unable to verify the GPAX of the specific category of each the curriculum that it was an important criterion in order to graduate. Therefore, the verification of these in the Faculty of Science used manual methods by students and the service staff. The students fill grade in the form and calculate their grades before submitting to the service staff. Then the staff rechecks the grade again with a calculator. This leads to delay and prone to errors. This study developed a web application prototype which covers 10 main processes, including register for login, authenticate, manage course structure, record grade, calculate GPAX and GPA of specific subject group, check the graduation conditions and report the result, send data for checking by student, check data from the system by staff, produce the report. The database has 11 tables that has 6 import screens and 2 reports that they can be filtered by course and status dimensions. The results of user’s satisfaction showed that the 30 students were at high satisfaction level, and the 4 users from education service staff, teachers and administrators were at the highest satisfaction level.