15 research outputs found
การอบแห้งพริกด้วยเครื่องอบแห้งอุณหภูมิต่ำที่เสริมการทำงานด้วยเครื่องอุ่นอากาศเทอร์โมอิเล็กทริค
No full textวารสารวิชาการและวิจัย มทร.พระนคร, 14(1) : 82-96This research objective was to apply thermoelectric module model TEC12710 as a preheater and dehumidifier for red chilies dryer. The heat side and cool side of Thermoelectric module affected by supplied electricity were used to produces the low humidity and warm air in preheater before charging to the main electric heater of dryer. Fresh red chilies were selected as a sample in the prototype testing during the use of preheater assisted main heater and using only main heater. The test results are compared with the sample dried under the natural sun drying. The experimental results show that the preheater can condense the moisture in air with the highest MER of 0.083 kgwaterh-1 at cold side of thermoelectric module
and can heat the air up in 10°C of temperature with hot side of thermoelectric module. The final moisture content of sample is only 10%wb with the slightly changed in color when compared with the sample from sun drying. The using of preheater with main heater gives a higher specific moisture extraction rate, lower specific energy consumption, 14 MJ energy used and can dry faster than 10 h when compared with the using of only main heater.Rajamangala University of Technology Phra Nakho
สมบัติกายภาพและอากาศพลศาสตร์ของข้าวเปลือกพันธุ์ขาวดอกมะลิ 105
No full textวารสารวิชาการและวิจัย มทร.พระนคร, ปีที่ 16, ฉบับที่ 2 (ก.ค.-ธ.ค. 2565), หน้า 99-112This research objective was to determine physical and aerodynamics properties of Khao Dawk Mali 105 paddy (Thai Jasmine paddy rice). The paddy sample in this test was prepared with different moisture contents in the range of 10-26%WB and air temperature in aerodynamics properties test was varied in the range of 50–100 OC. Test results were analyzed to determine the statistical mean difference by DMRT method (at P<0.05). It found that moisture content in paddy affects the difference of average length, width, and thickness of grain and results the difference of geometric mean diameter and degree of sphericity of paddy. An increase in paddy moisture results the increase of average bulk density and kernel density but it reduces the porosity of paddy. Moisture content in paddy affects the difference of terminal velocity. Moisture content in paddy and air temperature influenced the difference of average drag coefficient of paddy.Rajamangala University of Technology Phra Nakho
ค่าไอโซเทอมความชื้นของข้าวเปลือกพันธุ์ขาวดอกมะลิ 105
No full textวารสารวิชาการและวิจัย มทร.พระนคร, ปีที่ 16, ฉบับที่ 2 (ก.ค.-ธ.ค. 2565), หน้า 86-98The objectives of this research were the determination of sorption isotherms and the comparison of mathematical models to determine a suitable model in different temperature ranges for Khao Dawk Mali 105. This experiment was made by placing samples in containers which were contained saturated salt solutions to control the humidity in the ranges of 5.32 – 84.34 %RH and the hot air oven was used to provide temperature conditions at 25 and 70 oC. The samples were in containers until the mass of samples was constant so the equilibrium between the samples and the surrounding was reached and then the equilibrium moisture content was determined. The experiment found that for the same relative humidity in the air when the temperature increased, the equilibrium moisture content would decrease and for the same temperature in the air when the relative humidity increased, the equilibrium moisture content would increase. Furthermore, the comparison of models by analysis from R-Squared (R2) and Chi-Square (χ2) in each temperature found that Henderson model was a suitable model at 25 oC and Chung & Pfost was a suitable model at 70 oC.Rajamangala University of Technology Phra Nakho
อิทธิพลของรูปแบบความเร็วอากาศอบแห้งต่อการอบแห้งข้าวเปลือก
No full textวารสารวิชาการและวิจัย มทร.พระนคร, ปีที่ 16, ฉบับที่ 1 (ม.ค.-มิ.ย 2565), หน้า 165-176The objective of this research was to study the influence of drying air velocity characteristics on paddy drying. The pneumatic dryer prototype was used in this study. Test drying 15 kg of Hom Pathum paddy at 22 – 25% initial wet basis moisture content was tested drying under the drying air temperature 80OC until its moisture is 14% wet basis with the two drying air velocity characteristics. The first characteristic of drying air velocity is constant at 12.80 m/s and another is reduced velocity every 15 minutes throughout the test process from 12.80 - 8.44 m/s. Drying in a vertical tube with a diameter of 3.81 cm and height 1 m for study the drying behavior, drying rate (DR), specific energy consumption (SEC), and thermal efficiency of drying. The results showed that drying with constant air velocity gives a shorter time, higher drying rate, lower primary SEC consumption, and higher thermal efficiency than drying with reducing air velocity.Rajamangala University of Technology Phra Nakho
ผลของอุณหภูมิที่มีต่อค่าความต้านทานและความจุไฟฟ้าของข้าวเปลือกที่มีความชื้นแตกต่างกัน
No full textวารสารวิชาการและวิจัย มทร.พระนคร, ปีที่ 16, ฉบับที่ 1 (ม.ค.-มิ.ย 2565), หน้า 69-82This research proposes an application of resistive and capacitive soil moisture sensors to investigate the influences of paddy temperature on the electrical signal received from sensors when tested with paddy moisture in the range 9.2 - 22.75%wb at 40 - 80ºC to determine the relationship between paddy moisture and electrical signals. It was found that the mean signal values between 20 - 40 seconds from both sensors were inversely linear correlation with the moisture content of the paddy. Temperature is the factors that influence the measured electrical signal. R2, Adjust R2 (95% confidence interval), and RMSEC showed that the model developed from the resistive sensor signals was accurate in calculating the moisture content of paddy between medium to high temperature in range 60 - 80ºC more than the low temperature range. While the capacitive sensor signals model is accurate in calculating paddy moisture between low to medium temperature in range 40 - 60 ºC. Therefore, the resistive soil moisture sensor is possible and more suitable for applying as a paddy moisture sensor in the high temperature drying processes than a capacitor soil moisture sensor.Rajamangala University of Technology Phra Nakho
Empirical modelling of temperature in fogging greenhouse
No full textThe objective of this article is to evaluate the inside temperature of greenhouse and efficiency of fogging system under the influence of solar power. A 50% off sun shading roof was selected to test in this study. Testing is divided to 2 cases. Case I Measuring all of parameters without operate the fogging system and ventilation between 9.00 a.m. to 5.00 p.m. (Thailand’s time zone). Case II Measuring all of parameters with a fogging system that was controlled the relative humidity below 80% all day. The results show that the highest temperature in greenhouse is 50.13oC (no fogging and ventilation). the developed empirical model has an error 6.33% between numerical results and measured air temperature. In case of neglected solar power, the model showed that the fogging system can reduce the temperature in greenhouse in range of 7.05°C (18.44%) and the efficiency of fogging system is quite high (value is 57.36%). The important factor that influents on the air temperature in greenhouse is solar power. If we need to control the atmosphere in greenhouse by fogging system than the reduction of solar power is the most important controlling factor
Kinematics motion of paddy in hot air pulse flow
No full textThis research aims to study the characteristic of paddy motion under the hot air pulse flow in the drying tube length 2 m by using the kinematics motion analysis. The equations of paddy motion are analyzed to evaluate the pattern of paddy motion, total distance that the paddy can travel through the drying tube and Reynolds number of paddy. Results found that Model I, II and III consume the paddy travel time of approximately 1.3, 5.0 and 2.2 s and give a total distance of 2.6, 2.7 and 2.5 m and they have maximum travel velocity of 4.12, 1.37 and 1.85 m/s respectively. When considering the Reynolds number, the models I, II and III give the most values from similar calculations with 1,837, 1,816 and 1,821 respectively. Based on various parameters from all of models, Model III was the closest characteristic of paddy motion to the actual movement in the system
Optimization of carrier agents using mixture design for tamarind powder production
No full textThis research investigates the collective use of maltodextrin (MD), octenyl succinic anhydride (OSA), and gum arabic
(GA) to produce tamarind powders using the double drum dryer method. In this study, seven carrier mixture formulations were
specified using a simplex lattice mixture design and the physicochemical characteristics of the tamarind products associated with
the MD-OSA-GA combinations were assessed. Graphical optimization was utilized to identify the optimal MD-OSA-GA
concentrations that would produce a tamarind powder with the essential physicochemical characteristics that would closely
resemble the fresh tamarind pulp including total solids (TS), viscosity (VS), pH value (pH), and total acidity (TA). The optimal
mixture concentrations were 61.52 g, 28.48 g, and 10.00 g/100 g for MD, OSA, and GA, respectively, with the tamarind powder
possessing 39.88% TS, 0.27 VS, 3.04 pH, and 9.31% TA
