จำนวน Repository ( 1087 )

การวิเคราะห์ค่าความเป็นฉนวนของบุชชิ่งหม้อแปลงไฟฟ้าแรงสูง
การวิเคราะห์ค่าความเป็นฉนวนของบุชชิ่งหม้อแปลงไฟฟ้าแรงสูง

This article presents how the analysis an insulation of high voltage transformer bushing. The purpose is to analysis the moisture in the bushing to evaluate the approach for maintenance. The analysis rely on the principle of the Polarization and Depolarization Current (PDC) technique which is a technique for analyzing the insulation of high voltage equipment to test high voltage transformer bushing for a case study. This method is performed by energize 1000 Vdc into a bushing in period of time and then switch off the circuit for discharge current. Finally we calculate the moisture of main insulation of high volt bushing as well compare with standard moisture of criteria. The method is useful of preventive maintenance plane of high volt bushing and reduce the failure in the power system.

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การวิเคราะห์ปัจจัยที่มีผลต่อปริมาณน้ำมันตะไคร้หอมจากเครื่องกลั่นด้วยการออกแบบการทดลอง
การวิเคราะห์ปัจจัยที่มีผลต่อปริมาณน้ำมันตะไคร้หอมจากเครื่องกลั่นด้วยการออกแบบการทดลอง

The purposes of this research were to investigate the factors consisted of a temperature different parts of the lemongrass and a size of chopped lemongrass that affected to distillation of lemongrass essential oils. There are two experiments in this work. The first experiment investigated the factors by defining 1) temperature at 105 oC and 110 oC 2) different parts of the lemongrass (Leaves and trunk) and 3) sizes of chopped lemongrass at 1-2 cm and 15-20 cm respectively. 2k Factorial designs method was used for this experiment. In the second experiment the appropriate parameters from experiment 1 were used for 3 replicates to find an average of lemongrass essential oils. The results of first experimental analysis showed that the appropriate parameters were temperature parts of the lemongrass and sizes of chopped lemongrass at 110 oC leaves and 1-2 cm respectively. For the result of experiment 2 it was found that the average of lemongrass essential oils was 30.36 ml.

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การเตรียมกระดาษคราฟท์จากผักตบชวา ใบสับปะรด และกาบกล้วย
การเตรียมกระดาษคราฟท์จากผักตบชวา ใบสับปะรด และกาบกล้วย

This research had a main purpose for studying the utilization of water hyacinth as the key component of paper production mixed with the agricultural waste as pineapple leaves and leaf sheath of banana tree. The paper pulps were prepared from 5 g/l NaOH at 90-95oC for 3 hours then bleaching with 5 g/l Hydrogen peroxide at 90-95oC for 30 minutes. The whole pulps were detached improvement with 5g/l Acramine 3187 before paper establishment production. Finally the strength of obtaining papers was consideration and competition to any craft paper type. As the results the appropriate ratio of paper was 70% water hyacinth (stem) 10% pineapple leaves and 20% leaf sheath of banana tree. It had 31.19 kN/m2 for bursting strength tearing strength as 309.17 mN and 0.49 mm thickness. The basis weight was 183±5 g/m2. The achieved paper was equivalent as KI craft paper. It was presented for packaging boxes and other procedures.

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การเลือกเส้นทางการขนส่งสินค้าที่เหมาะสม โดยการวิเคราะห์การตัดสินใจแบบหลายหลักเกณฑ์
การเลือกเส้นทางการขนส่งสินค้าที่เหมาะสม โดยการวิเคราะห์การตัดสินใจแบบหลายหลักเกณฑ์

The objective of this research is to propose method for optimization route selection by Analytic Hierarchy Process (AHP) and The Technique for Order Preference by Similarity to The Ideal Solution (TOPSIS) model. The model was applied to case study route selection from Laem Chabang Port in Chonburi to Bangpoo Industrial Estate in Samut Prakan based on the criteria: cost of transportation transit time risk of freight damaged risk of infrastructure and equipment and risk of other factors. AHP was used to determine the relative weight of criteria. Additionally TOPSIS was used to select the best alternative routes. The result showed that the AHP-TOPSIS model which is new approach for route selection flexible decrease discrepancy from weighting more efficient than one either AHP or TOPSIS and not too complicated models compared to the other methods in multiple criteria analysis.

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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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