The optimum conditions of extracting pectin from vegetables and fruits are apples grapefruit lemons and bananas were studied. It was found that pectin from grapefruit peel gave good physical property white and has a relatively highest yield. Therefore in this study was interested to choose grapefruit peel as raw materials to optimum the conditions of pectin extraction. In the process of pectin extraction the temperatures of the extraction were studied at various 50 60 70 80 and 90 ?C by using hydrochloric acid for 24 hours. It was found that when the temperature increased the pectin extract was increased while at 80 and 90 ?C have a similar effect. After that pH conditions of the extraction were studied by various acids such as hydrochloric acid nitric acid and acetic acid at the same concentration of 1.0 molar at 80 C for 24 hours (1440 minutes). The results found that hydrochloric acid gave maximum pectin extracted yield. Finally the extraction times were studied at 30 60 90 120 and 1440 minutes using 1.0 M hydrochloric acid. From this work can optimized the pectin extraction condition as of 80 C and the extraction time was 90 minutes that gave maximum yield of pectin. At the otherwise the times of extraction have no effect to the amount of pectin. The potential from this study had satisfactory results can be used to improve the extraction of pectin system.

The objectives of the study were to find the arrival rate of applicants who applied to study at Rajamangala university of Technology Pra Nakhon North Bangkok Campus the service rate of admission officers and to analyze queuing system in order to improve the admission system. The sample was 1722 technical students who applied to study in 10 divisions in 2007 and 2008. The application data was collected every 10 minutes in each one-hour period from 09.00 am. to 16.00 pm. for 6 days. The study found that the distribution of the number of applicants was Poisson distribution. The highest arrival rate 1.29 students/min was at the second period and the lowest arrival rate 0.06 students/min was at the sixth period. The distribution of service time at each station was exponential distribution. The highest service rate 0.67 min/student or 1.49 students/min was at the second station entering data into a computer. Queuing analysis in this study was series network. The analysis found that the highest expected number of applicants in the system 150 students/hour was at the first station in the second period and in the sixth period there was almost none. The highest expected number of applicants in the queuing system 107.40 students/hour was at the first station in the second period. The highest expected waiting time in the system 1.92 min/student and in the queuing system 1.37 min/student were at the first station. The probabilities of none of applicants in the system at the first the second and the third station in the sixth period were high 0.970.95 and 0.98 respectively. The proper value of the expected number of applicants in the system set in this study was not more than 60 students/hour and not less than 30 students/hour. The proper value of the waiting time in the system was not more than 1 min/student and not less than 0.5 min/students for stations with more than one servers. The analysis found that at the first station one more server should be added in the second the third and the forth period and one less server should be reduced in the sixth period.