This research aims to develop the gypsum refractory board mixed with corn leaf coir. The 5 ratios of gypsum plaster: corn leaf coir: tap water: sodium silicate are equal to 1: 0: 1: 0.03 1: 0.100: 1: 0.03 1: 0.150: 1: 0.03 1: 0.200: 1: 0.03 1: 0.250: 1: 0.03 และ 1: 0.300: 1: 0.03 by weighted. The gypsum refractory boards were produce by casting in normal temperature (30 – 35 degree of Celsius). The properties testing of gypsum refractory board mixed with corn leaf coir followed the TIS 219-2009 standard (gypsum plasterboard) included: breaking load nail pull resistance deflection water absorption density and thermal conductivity coefficient. From the results 1: 150: 1: 0.03 is the most suitable ratio of gypsum refractory board mixed with corn leaf coir. This developed gypsum refractory boards can reduce the quantity of corn leaf waste and get the good thermal insulation gypsum refractory board products.

The study objectives of the electrical energy saving behavior of student in faculty of business administration Rajamangala University of Technology Phra Nakhon 1) to study psychological trait factor psychological state factor and situational factor in overall group and subgroup of the students’ electrical energy saving behavior in faculty of business admimistration RMUTP 2) to study the interaction effect between psychological trait factor psychological state factor and situational factors related to the students] electrical energy saving behavior in overall group and subgroup. The sample size was 361 students of bachelor’ s degree. The study factors were 7 independents future orientation and self-control) 1 psychological state factors (appropriate model from family knowledge on the electrical energy saving and the information about electricity saving). The dependent factor was the electrical energy saving behavior. Frequency percentage arithmetic mean and standard deviation were used for descriptive statistic while stepwise multiple regression and two-way ANOVA were used for inferential statistics in overall group and subgroup according to social demographic characteristics. The research findings were as follows : Firstly all 7 factors of psychological trait factors psychological state factor and situational factoe could predict 52% of variance of the electrical energy saving behavior. The most prediction power factors were appropriate model from family positive attitude towards saving behavior receives electricity saving information and well-being respectively. Secondly the interaction effect was found well-being and electricity saving information with the electrical energy saving behavior of student which was male and female group and freshman and sophomore group junior and senior group G.P.A above 3.00 and parents’ income lower than 30000 thb Thirdly the interaction effect was found the future orientation and self-control and knowledge on the electrical energy saving behavior with the group of student who mother has an education lower than undergraduate.

This paper presents about the defrosting time of evaporator in refrigerator by using the temperature different between evaporator and chilling area. This temperature different concept could control the defrosting system to operate according to the load. It also helps controlling the operation of fan motor to be able to operate in accordance with the defrosting time. In general system the timer is set at the highest humidity season which cause the unneccessary defrosting cycle even in low humidity season. This general system create the west of power usage colling system. These can cause time-consuming in defrosting process in the low humidity season and cause the unnecessary usage of power to cooling system. This research is to develop the controller for the defrosting system at evaporator from the investigation. As the results we have found that the defrosting system at evaporator according to its load made the refrigerator can decrease the power about 8% when comparing to constant time evaporator system

The Kaolinite development process to improve the characteristics. The Kaolinite mixed ratios are 10% 20% 30% and 40% and the result indicated that the experiment mortar-mix ratio at 0:8:2.75:0.2:0.05:0.04:0.5 of cement powder sand Kaolinite limestone superplasticised and clean water compared to No MK control sample covered ASTM standard in tensile strength more than 100 ksc compressive strength of MK20% with superplasticised at 434 ksc. The water absorption values under the standard passed

The objectives of this research are to study the production step proper ratio physical properties mechanical properties thermal insulation and sound insulation efficiency of concrete blocks mixed with coconut shell ash. The ratios of concrete block mixed with coconut shell ash include Portland cement type1: quarry dust: coconut shellash which equal to 1: 6.8: 0.2 1: 6.7: 0.3 1: 6.6: 0.4 1: 6.5: 0.5 and 1: 6.4: 0.6 by weight. Water per cement ratio are 0.6 by weight. The concrete block samples were casted by the general production as same as the ordinary concrete blocks and were tested follow TIS.58. From the results the best amount of coconut shell ash which put into concrete block is 1: 6.7: 0.3 of ratio. The proper ratios of coconut shell ash can decrease the density or weight and increase the thermal insulation and sound insulation efficiency of concrete blocks. However the high amounts of coconut shell ash effect to decrease the mechanical properties concrete blocks that are lower than TIS.58 standard.