จำนวน Repository ( 1174 )

จิตสำนึกการอนุรักษ์สิ่งแวดล้อมของนักศึกษาคณะบริหารธุรกิจ มหาวิทยาลัยเทคโนโลยีราชมงคลพระนคร
จิตสำนึกการอนุรักษ์สิ่งแวดล้อมของนักศึกษาคณะบริหารธุรกิจ มหาวิทยาลัยเทคโนโลยีราชมงคลพระนคร

The study was aimed to investigate environmental conservation conscience and related knowledge of Business Administration undergraduates at Rajamangala University of Technology Phra Nakhon. It was also intended to examine the relationship between the environmental conservation knowledge and the students’ environmental conservation conscience. The samples were 208 fourth year students studying in the second semester of at the Faculty of Business Administration in 2013. The data were collected through the questionnaire regarding the environmental conservation conscience and related knowledge and were analyzed by the frequency distribution percentage distribution standard deviation t-test and One – Way ANOVA. In case of 0.05 statistical differences was found Scheffe’s method was applied for adjusting significance levels in a linear regression analysis to account for multiple comparisons as well as Pearson Product Moment Correlation statistically significant at 0.05 level. The result showed that Business Administration undergraduates highly displayed their environmental conservation conscience and related knowledge and moderately related (r = 0.407) and statistically significant at level of 0.05.

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การเพิ่มประสิทธิภาพเครื่องปรับอากาศแบบแยกส่วนโดยใช้ลมเย็นจากพัดลมระบายอากาศ
การเพิ่มประสิทธิภาพเครื่องปรับอากาศแบบแยกส่วนโดยใช้ลมเย็นจากพัดลมระบายอากาศ

This research aimed to find the possibility of increasing the efficiency of the split type air conditioner by using the cool air from a ventilation fan in the air conditioning room for cooling the condenser. Two simulation rooms size 120x120x200 centimeters were constructed. The first room was installed the evaporator and the second room was installed the condenser and a ventilation fan in the lower part of the air conditioning room to deliver the cool air for cooling the condenser. Then the system was tested and compared the energy efficiency ratio and the reduced power consumption between turning on and turning off a ventilation fan. The results of the proposed air conditioner system observed from the various load conditions at 0% 30% 60% and 100% The surrounding temperature of the condenser ranged in 30C 40C and 50C It was found that the energy efficiency ratios increased in the range of 2.94% to 5.92% and the power consumptions decreased in the range of 4.56% to 12.5% The possibility of increasing the efficiency of the air conditioner system by using the cool air from ventilation fan in the air conditioning room for cooling the condenser was verified by the increased energy efficiency ratios and the reduced power consumptions.

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อันตรายด้านจุลินทรีย์และจุดควบคุมวิกฤติการผลิตอาหารโรงเรียน : ข้าวคลุกกะปิ
อันตรายด้านจุลินทรีย์และจุดควบคุมวิกฤติการผลิตอาหารโรงเรียน : ข้าวคลุกกะปิ

The objectives were to study microbiological hazard of Khao kluk ka pi for school food service risk assessment and critical control points (CCP) according to HACCP principles.The production of Khao kluk ka pi had the improper hygienic practice. Thus TPC counts were found in shallots coriander and chilli at 1.9×106 3.2×107 and 5.9×106 cfu/g respectively and found E. coli in chopped coriander more than 1100 MPN/g. The TPC S. aureus C. perfringens Salmonella and V. parahaemolyticus were not detected in cooked ingredients. The number of TPC in Khao kluk ka pi held at ambient temperature for 0 2 4 and 6 hours were founed an increase from 1.2×106 cfu/g to 7.6×106 1.8×107 and 3.4×108 cfu/g respectively that was as a result of the uncooked ingredients and mixing process. The microbial numbers were increased when this food was held for a long time before serving. The CCP of Khao kluk ka pi production were indicated at the process of washing raw vegetables cooking process and holding cooked food at room temperature for a long time before serving.

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อิทธิพลของความเร็วรอบที่ส่งผลต่อสมบัติทางกลของการเชื่อมอะลูมิเนียมต่างชนิด ระหว่าง SSM7075 กับ SSM356 ด้วยการเชื่อมเสียดทาน
อิทธิพลของความเร็วรอบที่ส่งผลต่อสมบัติทางกลของการเชื่อมอะลูมิเนียมต่างชนิด ระหว่าง SSM7075 กับ SSM356 ด้วยการเชื่อมเสียดทาน

The objective of this research is to study how rotation speeds affect mechanical properties with friction welding between semi-solid metal 7075 aluminum alloys and semi-solid metal 356 aluminum alloys. The factor of interest is rotation speeds with different conditions at 800 1000 1200 1400 and 1600 rpm respectively. 1.8 millimeter for burn of length 30 seconds for welding time and clockwise rotation are set as a control constant condition for the entire experiment. After friction welding we found that different rotation speeds significantly affected mechanical properties of these alloys. At rotation speed 1400 rpm the maximum tensile strength is 122.24 MPa and the maximum hardness in welded zone is 140.5 HV. The microstructure size is 2.250 µm long and 2.144 µm wide. Its size in welded zone is practically small because of friction force. Moreover this friction force causes the mixture of MgZn2 and Mg2Si in welded zone.

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การใช้แผ่นยางแทนกำมะถันเคลือบผิวในการทดสอบกำลังอัดของคอนกรีต
การใช้แผ่นยางแทนกำมะถันเคลือบผิวในการทดสอบกำลังอัดของคอนกรีต

This research aims to study the using a rubber sheet instead of the sulfur-capping accordance with ASTM C 617 in the compressive strength of concrete testing. The three of the compressive strength of concrete i.e. 180 240 and 320 ksc were the scope of study. The test results showed that the concrete with using a rubber sheet (fc (3)) had higher compressive strength than the standard concrete with sulfur-capping (fc (2)) at 7.7%. Therefore the adjustment factor from using a rubber sheet instead of the sulfur-capping in the compressive strength of concrete testing was 0.923; the compressive strength of concrete is equivalent to the standard testing. The relationship of compressive strength of concrete between fc (2) and fc (3) is fc (2) = 0.88 fc (3) + 12.04 with a correlation coefficient (r) of 0.988.

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