จำนวน Repository ( 1852 )

การย่อยสลายภายใต้สภาวะไร้อากาศของสารอินทรีย์ประเภทเศษอาหารเข้มข้นในกระบวนการผลิตแก๊สชีวภาพ
การย่อยสลายภายใต้สภาวะไร้อากาศของสารอินทรีย์ประเภทเศษอาหารเข้มข้นในกระบวนการผลิตแก๊สชีวภาพ

The purposes of this research were to investigate anaerobic digestion of concentrated food waste in biogas production system at mesophilic temperature (37 C). The effect of grinding and pH controlled at 6.20 and 7.00 on methane production were also studied. It was found that the ability of mix bacteria which had initial concentration of 2100 mg/l for digesting concentrated food waste with grinding was higher than that without grinding because of the increase in surface area (about 1.37 time). In this system the optimum condition for bacteria growth was found at pH 7.00. Under optimal condition the digestion efficiency in term of chemical oxygen demand (COD) removal was 18.81% higher corresponding to an increase in methane production rate (19.10%) than other conditions

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การพยากรณ์ราคาข้าวโพดเลี้ยงสัตว์ของประเทศไทย
การพยากรณ์ราคาข้าวโพดเลี้ยงสัตว์ของประเทศไทย

The purpose of this research was to construct the appropriate forecasting model for the prices of field corn in Thailand using four time series analysis methods including Box-Jenkins method Holt’s exponential smoothing method damped trend exponential smoothing method and combined forecasting method. Time series data from the website of the Office of Agricultural Economics with total 227 months during January 1997 to November 2015 are used and divided into two series. The first 216 months from January 1997 until December 2014 used to build the forecasting models and the last 11 months from January until November 2015 used to compare the forecasting methods accuracies via the criteria of the lowest mean absolute percentage error and root mean squared error. Research finding indicated that combined forecasting model was the most accurate.

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กระบวนการผลิตผักแกะสลักบรรจุในภาชนะปิดสนิท
กระบวนการผลิตผักแกะสลักบรรจุในภาชนะปิดสนิท

The study of vegetable-carved processing packed in hermetically sealed container for 5 types of plant e.g. carrot pumpkin radish green papaya and cucumber which carved into rose or leave shape and preserved in acidified-pickle (7.23% vinegar 64.81% water 0.81% salt 27.00% sugar and 0.15% lactic acid pH 3.27). The processing were conducted by sanitized carved-carrot pumpkin and radish in peroxyacetic acid solution (80 mg/l 3 min) or dipped in tap water (3 min) for green papaya and cucumber. Then all carved-vegetables were blanched in calcium chloride solution (0.5% 3 min) followed by preserved in acidified-pickle in plastic box with a lid and stored for 4 days at room temperature (25ºC). The results showed that pH and °Brix decreased during 4 days storage and showed obviously tended to equilibrium. However carved-radish and cucumber were spoiled by microorganisms as a film on the surface of pickle solution and gas bubble was occurred inside a container on 4th days of the storage. Hence carrot and pumpkin were used in the next experiment which preserved in preservative-added recipe (27.03% vinegar 27.03% water 0.9% salt 45.05% sugar and 200 ppm sodium metabisulfite pH 3.39) with hot-filled method in glass bottle. Treatment was compared with carved-vegetables preserved in acidified-pickle and kept at 4oC as the control. The pH of samples of pickle solution carved-vegetables and mixed-sample of both treatments showed lower than 4.6 and °Brix were gradually decreased during storage periods.The appearance of both treatments were maintain good and not different between treatments. Shelf-life of carved-carrot -pumpkin and -radish stored in hermetically sealed container was up to 7 days. Total bacteria count Escherichia coli yeast-molds were not exceeded than the standard limited by Ministry of Public Health and Staphylococcus aureus was not detected

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ผลกระทบของตัวแปรในกระบวนการดัดขึ้นรูปแบบอิสระที่ส่งผลต่อพฤติกรรมการดีดตัวกลับของโลหะแผ่นอลูมิเนียมผสม AA6016
ผลกระทบของตัวแปรในกระบวนการดัดขึ้นรูปแบบอิสระที่ส่งผลต่อพฤติกรรมการดีดตัวกลับของโลหะแผ่นอลูมิเนียมผสม AA6016

Springback behavior is a major problem of sheet metal forming process. Especially aluminum alloy which often encounter such problems often. At present aluminum alloy is increasingly of used in the automotive industry for replace of the steels due to its lightweight and good finished surface. This work aims study to springback behavior of cold rolled aluminum alloy (AA6016) during air-bending process by ISO7438/2010 test standard. To analyze the influence of bending process parameter are included: sheet thickness punch radius bending angle die open and the ratio of bending radius and material thickness (r/t) effecting to springback behavior. The results are clearly that the springback angle is likely to increase with increase of the punch radius size of die open and the ratio of punch radius and sheet thickness and the springback tenor to decrease when the sheets thickness and bending angle increased. The increased bending angle will resulted to bending surface region is roughness increase and crack occurred to follow. As a result the bending force and the springback angle decreased.

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ระบบจัดการการใช้อินเทอร์เน็ตด้วยโพรโทคอลเรเดียส
ระบบจัดการการใช้อินเทอร์เน็ตด้วยโพรโทคอลเรเดียส

The purpose of this research was to design and develop an internet management system using radius protocol for a school. The system was developed by PHP language MySQL database and radius protocol. It allowed an administrator to grant users permission to access the internet manage their accounts check their status and record their usage history in files in addition to teachers being able to limit the use of the internet in their classrooms. The system evaluation process was divided into two parts. First the efficiency of the system was evaluated by the administrator and it was found that the system can work as required. Second the system performance was evaluated in terms of network security functional requirement and processing speed by the completion of a questionnaire by five experts. User-friendliness was evaluated by the completion of a questionnaire by 115 teachers and students. Results showed that the average efficiency was 4.22 with a standard deviation of 0.07. It can be concluded that the effectiveness of the developed system was at a high level and its application was beneficial for other organizations

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