จำนวน Repository ( 36 )

Two-dimensional transient model for prediction of temperature profile at heat pipe wall
Two-dimensional transient model for prediction of temperature profile at heat pipe wall

Distribution trend of transient temperature profile of copper heat pipe from the start-up of outer wall temperature of evaporator section until the temperature was steady was studied. A two-dimensional model used numerical solution which based on finite difference method. The transient temperature distributions measured in all 3 heat pipe sections were compared with results from the numerical solution of the two-dimensional model that utilized the concept of temperature distribution in the pipe wall during transient operation. Results showed that the experimental trend and the theoretically predicted temperature profiles were similar. Moreover there was good agreement when compared with the numerical simulation of Mistry et al. (2010). Therefore the numerical-validated heat pipe temperature distributions were successfully simulated in a two-dimensional model.

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การทดสอบการอัดตัวของวัสดุผสมภายใต้สภาวะอุณหภูมิต่างๆ
การทดสอบการอัดตัวของวัสดุผสมภายใต้สภาวะอุณหภูมิต่างๆ

Brake system is used the friction between disk and pads. In the driving conditions the brake behavior from the driver is difference. Based on this reason the damage on disk and pads are occurring. Nowadays the ratio of compound materials in pads is several and involved automotive industry has not available enough to experiment. Thus it is difficult to brake pads damaged analyzing in several driving conditions. In this problem the mechanical property tester is main tool for experimental works and test procedure base on the Brake lining and disc brake pads compressibility JIS D 4413. The experiment emphasizes on the flexibility behavior and internal energy by volume with 3 types of brake lining and pads. For the experiment focused on conditions by normal apply brake repeat apply brake and suddenly apply brake. The results revealed the normal apply brake condition the maximum and minimum of flexibility behavior was appeared on brake lining and pads type A and type C with testing temperature at 200C. By the repeat and suddenly apply brake conditions the brake lining and pads type C and type A with 300C is given to the maximum and minimum flexibility behavior. In case of internal energy by volume the maximum and minimum energy was appeared on pads type C and type B at the 30C of testing temperature. For the testing temperature at 200 and 400C the pads type A and type B were got the maximum and minimum energy respectively. On the other hand at the high flexibility behavior is given to high internal energy at the high temperature of the apply brake condition.

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Fatigue life evaluation of a closed-loop oscillating heat-pipe with check valves (CLOHP/CV) at operated temperature
Fatigue life evaluation of a closed-loop oscillating heat-pipe with check valves (CLOHP/CV) at operated temperature

This study evaluates the fatigue life of a closed-loop oscillating heat-pipe with check valves (CLOHP/CV). The method was predicting the fatigue life of the copper tube to apply for the CLOHP/CV. The fatigue test was carried out by using the specimens made of copper tube (C1220) at the temperature of 293 (room temperature) 473 and 573 K. The three types of hourglass shaped specimen included uniform type one-wave type and two-wave type specimens. It was found that the effect was a direct extension of material structures of specimen and hourglass shaped. It can be said that the number of cycles to failure (Nf) of the two-wave type specimen hourglass shaped specimen was rather sensitive to fatigue motion during testing and the temperature of 573 K has the greatest failure impact.

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Temperature Reduction in Hydroponic Planting System Using Heat Pipe
Temperature Reduction in Hydroponic Planting System Using Heat Pipe

This paper presents an establishment of a mathematical model to determine the optimal size of heat pipe (thermosyphon) heat exchanger for reduce the inlet air temperature in evaporative cooling system of greenhouse. The condition of a mathematical model is the total length of heat pipe is 1.5 m. A mathematical model will determine the optimal value of evaporator section and condenser section. The range of evaporator length is 0.5 – 1.4 m with an increment of 0.1 m and condenser length is in range of 0.1 – 1.0 m with an increment of 0.1 m. The inlet air temperature in evaporative cooling of greenhouse is depend on ambient temperature about 35 degree Celsius. While the cooling water temperature is 20 degree Celsius. Evaporative pad of evaporative cooling system is 2 m in width and 7 m in length. From the conditions above the optimize results from a mathematical model are as follows: evaporator section length is 0.9 m and condenser section length is 0.6 m moreover it was shown that investment net saving and maximum heat rate are 79.83 Thousand Baht 0.552 Million Baht and 15.6 kW respectively.

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การประดิษฐ์เซรามิกบิสมัทโซเดียมซาแมเรียมไททาเนต-แบเรียมไททาเนตด้วยเทคนิคการสังเคราะห์แบบเผาไหม้
การประดิษฐ์เซรามิกบิสมัทโซเดียมซาแมเรียมไททาเนต-แบเรียมไททาเนตด้วยเทคนิคการสังเคราะห์แบบเผาไหม้

Ceramic Bismuth Sodium Samarium Titanate - Barium Titanate at the concentration of samarium 0.04 mol% was preparing by ball mill technique. This research has increased the temperature in the combustion process at different temperatures from 940960 and 970 degrees Celsius for 7 hours. The results showed that firing at different temperatures made the ceramic beads very dense. In addition the study of the crystal structure by XRD technique to study the structure of the ceramic BSNT-BT found that the structure is the same substances in the ceramic group BaTiO3. The results of the study of dielectric properties and ferroelectric properties It was found that the dielectric and P-E hysteresis loops were related and tend to correlate with increasing density with sintering temperature. The mechanical properties of ceramics were tested by measuring the hardness of ceramics at different temperatures with temperatures affecting the changes in various properties of ceramics BSNT-BT.

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