จำนวน Repository ( 45 )

การศึกษาพารามิเตอร์ในการขึ้นรูปแผ่นเกราะเซรามิกส์รูปร่างหกเหลี่ยมกันกระสุน
การศึกษาพารามิเตอร์ในการขึ้นรูปแผ่นเกราะเซรามิกส์รูปร่างหกเหลี่ยมกันกระสุน

This research had two objectives that were to study parameters for forming bulletproof ceramic armor plates and to create a model of a bulletproof ceramic armor plate for small armored regular trucks. The parameters used to form a ceramic armor plate contain the thickness of the armor plate and the compressive strength which affects the density distribution of the green compact. A ballistic ceramic armor plate with a hexagonal shaped material was created as a concave bulletproof plate. Extrusion results displayed that the hexagonal material was formed at a very high density on the side surface of the armor plate but with uneven capacity distributed across the overall plate due to the friction occurring on the wall of the mold. The finite element method particularly at the Ansys/Explicit Dynamic tools were applied to analyse the damage of bulletproof plates. The model of a concave-shaped bulletproof plate was set for the SKD11material influencing the changes in the direction of the bullet firing when the bullet hit the bulletproof plate at a velocity of 880 m/s in accordance with the NIJ 4 standard. The bullet was made of tungsten carbide and the ceramic armor plate was built with a size of 300×300 mm and thicknesses of 14 16 18 and 20 mm. The bullet was fired into the center part and onto the curved surface of the ceramic plate. The result shows that the armor plate could not resistant to penetration. In this situation the direction of the bullets movement against the armor plate especially at a curved surface as a slope could result the deflection of the bullet direction as well as reduction of penetration capability.

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การศึกษาอิทธิพลของอายุการใช้งานที่ส่งผลต่ออัตราการเสื่อมของสัมประสิทธิ์ความเสียดทานยางล้อ
การศึกษาอิทธิพลของอายุการใช้งานที่ส่งผลต่ออัตราการเสื่อมของสัมประสิทธิ์ความเสียดทานยางล้อ

The objectives of this research are to study the rate of deterioration of tyre friction coefficient and investigate the quality of new and old tyres that are currently in use. A set of the rolling resistance testing was designed and set up to work with the single dynamometer according to speed 80 km/h tire load 4660 N and inflation pressure 30 psi. There were three tire samples new tire one year used tire and two year used tire to find the rolling resistance coefficients. The finding shows that the rolling resistance was inverse variation with tire aging. For instance the new tire (1st sample) had the highest rolling resistance on the other hand the two year used tire (3th sample) had the lowest rolling resistance. Moreover the rolling resistance coefficients were inverses variation with tire aging. Besides the one year used tire had the average of the decreasing rate of the rolling resistance coefficient at 0.03689 N/kN per a week while the two year had the average of the decreasing rate of the rolling resistance coefficient at 0.03671 N/kN per a week. Furthermore the result also revealed that the rolling resistance coefficients nonlinearly decreased comparing to the tire aging.

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การพัฒนารถประหยัดเชื้อเพลิงโดยการปรับความดันการฉีดเชื้อเพลิงด้วยโปรแกรมคอมพิวเตอร์
การพัฒนารถประหยัดเชื้อเพลิงโดยการปรับความดันการฉีดเชื้อเพลิงด้วยโปรแกรมคอมพิวเตอร์

The study of the efficiency of fuel consumption by adjusting the fuel injection pressure is basically one optimization method to maximize the engine combustion. In this current study the Honda wave 110 cc. engine has been used to test in particular the fuel injection by adjusting the pressure of injector. To control the pressure of injection was made by automatic valve injectors with three different pneumatic pressure which were 2 2.5 and 3 bars respectively and the similar running distance of 5km. The results showed that at 2 bars the obtained fuel saving was 1020.68 km/L and the speed at 25.23 km/h which corresponded to the highest CO2 emissions during the engine combustion.

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Effectiveness investigation of evaporative cooling using radiator for pre-cooling system
Effectiveness investigation of evaporative cooling using radiator for pre-cooling system

Due to the systems of mechanical vapor compression have a high energy consumption for air-conditioned space. Therefore the system of evaporative cooling presents as a promising alternative option for the air-conditioning system. Moreover the pre-cooling system is normally used to reduce an intake ambient air temperature before the air-conditioning system. As mentioned above this research aims to investigate the effectiveness of evaporative cooling system by using a car radiator for air per-cooling. In this research the commercial car radiator was used for cooling inlet ambient air by cooling water. The evaporative cooling system consisted of evaporative cooling panel with a maximum water rate of 40 lite/minute and a maximum air rate of 5100 m3/hr. The results show that most suitable water flow rate of radiator is 10 lite/minute and this radiator can make the differences of air temperature of about 8.9oC. Moreover the results also show that the effectiveness of evaporative cooling system could reach about 73.31% with a maximum sensible heat of 8.43 kW.

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การการศึกษาพฤติกรรมค่าความจุความร้อนของวัสดุความเสียดทาน
การการศึกษาพฤติกรรมค่าความจุความร้อนของวัสดุความเสียดทาน

Nowadays one of the automotive engineering is conductivity of brake pads playing a role in friction coefficient which means safety of customer. Thus thermal properties have been improved using composited materials. This project aims to study the heat capacity behavior of 3 different brake pads which are supported by the company Compact International (1994) Ltd. For experimental works temperature based on brake condition was simulated from 05 to 003°C at 5 MPa of pressure. By standard JIS D4413 testing condition of pressure was referred. The heat capacity values of brake pads are calculated under the temperature conditions. As a result of testing brake pad made of copper or high metal powders result in relatively low heat capacity. On the other hand brake pads containing fiber and a large amount of fillers result in an increased heat capacity and stability in various temperature conditions. The heat capacity varied according to the operating temperature. In addition the lubricant contained in the brake pads affects the higher heat capacity and stability at various temperatures.

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