จำนวน Repository ( 2131 )

ผลของแรงต้านอากาศต่อการตกของกรวยกระดาษด้วยเทคนิคการวิเคราะห์วิดีโออัตราเร็วสูง
ผลของแรงต้านอากาศต่อการตกของกรวยกระดาษด้วยเทคนิคการวิเคราะห์วิดีโออัตราเร็วสูง

This research was aimed to study of the effect of dragging force on paper cone falling by using the high-speed video analysis technique. Four different sizes of paper cones ranged from 3.00-5.70 centimeter were used. The cones having the same mass of 12 g and falling from 2.50 meters height were recorded for 240 frames per second and then were analyzed using the Tracker Video Analysis software. The results showed that (1) all four different sizes of paper cones were not freely fall with the Earths gravity due to indirect proportion with time of theirs speeds. The terminal speed of two large cones having diameter of 5.00 and 5.70 centimeters were 4.42±0.03 and 3.97±0.04 meters per second respectively. Only 0.87% of these experimental values were different from the theoretical ones. (2) The theoretical trajectory of these cones falling using the terminal speed from the experimental agrees with the theoretical ones. (3) The experimental drag force showed a second order function of the paper cone’s speed. The evaluated drag force during terminal area is approximately equal to the cone weight. Thus this technique can help students and teachers to visualize simple physics phenomena and relate them to the physics principles learnt in the classroom

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การพัฒนาต้นแบบเครื่องยนต์ที่ใช้น้ำมันดีเซลและแอลพีจีเป็นเชื้อเพลิงสำหรับการเกษตร
การพัฒนาต้นแบบเครื่องยนต์ที่ใช้น้ำมันดีเซลและแอลพีจีเป็นเชื้อเพลิงสำหรับการเกษตร

According to the research entitled “the innovative engine prototype powered by diesel and LPG as fuel for agricultural” in 2019 the problems found while using the engine were as follows: the accumulated heat in the auxiliary combustion chamber reached 300 C in case of gasoline engine use and a lot of black smoke in the exhaust was found at the speed higher than 1800 rpm in case of a diesel engine use. In order to extend the research and solve two foresaid problems the objectives of this study were 1) to develop an auxiliary combustion chamber for cooling 2) to develop a scalable gas-air mixing device and 3) to compare diesel and LPG consumption rates by modifying a small diesel engine Yanmar version TF120DI to install LPG fuel systems and ignition system. In addition a gas-air mixing device was modified while an auxiliary combustion chamber was developed to reduce the compression ratio to the same level as the gasoline engine for replacing the position of the original diesel fuel injector. This method could support LPG fueling only whose function was characterized by the function of a gasoline engine. The auxiliary combustion chamber could be removed and then installed a diesel injector to return using diesel fuel. From an experiment to compare the modified engine operating as a gasoline engine it was found that the temperature of the auxiliary combustion chamber and the temperature of the engine cylinder head of Honda GX160 were measured at the maximum speed of 182 C and 186 C respectively. It was found that carbon monoxide content was 0.41 % and 1315 ppm hydrocarbons. When used as a diesel engine it was found that the black smoke was exhausted at 1.5 % which was similar to the diesel engine before the modification. From the experiment of using the power engine for pumping water with an Irrigation propeller pump with the diameter of 8 inch at a constant engine speed of 1000 rpm it was found that the average diesel usage was 0.65 kg/hr or about 0.77 L/hr with the cost of 21.00 Baht/hr and if using LPG as fuel the average LPG consumption was 0.57 kg/hr with the cost of 13.71 Baht/hr which could save up to 34.71 % of costs.

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การพัฒนาแบบจำลองและการพยากรณ์ดัชนีรังสีอัลตราไวโอเลตรายชั่วโมง โดยใช้โครงข่ายประสาทเทียมในจังหวัดสงขลา
การพัฒนาแบบจำลองและการพยากรณ์ดัชนีรังสีอัลตราไวโอเลตรายชั่วโมง โดยใช้โครงข่ายประสาทเทียมในจังหวัดสงขลา

In this work solar erythemal ultraviolet radiation (EUV) which affects human skin and skin cancer was investigated at Songkhla province (7.2°N 100.6°E). EUV was converted to UV index then the data was used for model development and forecasting of hourly UV index using Artificial Neural Network (ANN). The ANN model has one input layer two hidden layers and one output layer. This input layer consists of extraterrestrial erythemal ultraviolet radiation solar zenith angle aerosol optical depth and cloud index which affect ultraviolet radiation and the output layer is hourly UV index. The results show that hourly UV index obtained from ANN and that from the measurement are in reasonable agreement with root mean square difference of 12.8% and mean bias difference of -2.4%. For forecasting of the hourly UV index the data for 7 days earlier was used for forecasting the next UV index for one day or nine-hour (08:00 am.-16:00 pm.). Multi-layer perceptron and back propagation algorithm were used in the model forecasting. The results show that the UV index from the model forecasting is reasonable agrees with UV index from measurement with root mean square difference of 17.0% and mean bias difference of 0.3%.

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การตรึงอะโซโตแบคเตอร์แบคทีเรียตรึงไนโตรเจนในอากาศด้วยวัสดุธรรมชาติและผลต่อการเจริญเติบโตของผักกวางตุ้งในดิน
การตรึงอะโซโตแบคเตอร์แบคทีเรียตรึงไนโตรเจนในอากาศด้วยวัสดุธรรมชาติและผลต่อการเจริญเติบโตของผักกวางตุ้งในดิน

Nitrogen is an essential nutrient for plant growth. When the plants have been grown for a long-term effect to decreased nitrogen in soil and insufficiency of the plant growth. One biological method for increasing the nitrogen content in soil is utilize of free nitrogen-fixing bacteria Azotobacter. Therefore the objective of this research was to search natural material suitable for Azotobacter fixation. The 10 natural materials were observed physical structure and investigated the ability of natural materials for Azotobacter fixation. The results showed that water hyacinth and bagasse stalks were fixed the Azotobacter of 2.43x108 and 1.94 x108 CFU per gram of each natural material respectively. After that the selected fixed Azotobacter of water hyacinth and bagasse stalks were studied the growth of Brassica Chinensis. This experiment was designed to 4 treatments. The first treatment was mixed of water hyacinth stalks and the Azotobacter. Second treatment was mixed of bagasse stalks and the Azotobacter. The third treatment was the Azotobacter only. The last treatment was soil only. The results indicated that the average of plant growth include height leaf number root length fresh weight and dry weight of the mixed of water hyacinth stalks and the Azotobacter had significantly higher growth rates than other treatments. The total nitrogen was also increased 1.4 fold in the soil. All results suggest that the water hyacinth stalk is alternative for the fixation of the free nitrogen-fixing bacteria Azotobacter as induce nitrogen in the soil and plant growth promotion.

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การพัฒนาระบบบริหารงานพัสดุ คณะศิลปศาสตร์ มหาวิทยาลัยเทคโนโลยีราชมงคลพระนคร
การพัฒนาระบบบริหารงานพัสดุ คณะศิลปศาสตร์ มหาวิทยาลัยเทคโนโลยีราชมงคลพระนคร

This research is to develop an internal inventory management system. Faculty of Liberal Arts Rajamangala University of Technology Phra Nakhon To evaluate the results of the use of information systems for managing supplies within the Faculty of Liberal Arts Rajamangala University of Technology Phra Nakhon The data was collected between October 2019 and September 2020 as a survey research using questionnaire tools. It consists of 4 parts: 1) general information of the respondents which is demographic characteristics 2) current condition and needs of the parcel management system. Faculty of Liberal Arts University of Technology Rajamangala University of Technology Phra Nakhon 3) The efficiency of the procurement management system Faculty of Liberal Arts Rajamangala University of Technology Phra Nakhon and 4) satisfaction of the procurement management system. Faculty of Liberal Arts Rajamangala University of Technology Phra Nakhon With the sample groups in this research are Support personnel Under the Faculty of Liberal Arts Rajamangala University of Technology Phra Nakhon comprised of 21 persons. The data analysis used descriptive statistics for demographic characteristics. The study found that Current conditions and procurement development guidelines Faculty of Liberal Arts Rajamangala University of Technology Phra Nakhon Overall and from the bottom to the bottom including parcel payment Parcel picking Accounting for parcel control And material storage respectively efficiency of the parcel management system Faculty of Liberal Arts Rajamangala University of Technology Phra Nakhon Overall and each side Very level When sorting the efficiency of the parcel management system in descending order namely the information security aspect of the system. Aspects to meet the needs of system users Functional aspects according to the system function And the ease of use of the respective system and the users satisfaction with the parcel management system. Faculty of Liberal Arts University of Technology Rajamangala Overall and each side Very level When sorting the users satisfaction with the parcel management system descending namely the aspects of meeting the needs of the system users. Information security in the system Ease of use And functional aspects according to the systems function respectively

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