การวิจัยนี้เป็นการศึกษาสมบัติของโลหะเงินเจือต่า 58.33% ที่มีธาตุทองแดง (Cu) และดีบุก (Sn) เป็นธาตุผสม ซึ่งมีปริมาณการผสมอยู่ในช่วงระหว่าง 36.66 - 41.57% และ 0.10-5.01% ตามล่าดับ โดยท่าการเปรียบเทียบกับสมบัติของโลหะเงินสเตอร์ลิง 925 และโลหะเงินเจือต่า 58.33% เพื่อศึกษา วิเคราะห์อิทธิพลของธาตุเจือทองแดงและดีบุกที่มีผลต่อสมบัติทางกลและโครงสร้างจุลภาของโลหะเงินเจือ ต่า 58.33 wt% AgCuSn และหาปริมาณของธาตุเจือทองแดงและดีบุกที่เหมาะสมในการผลิต เครื่องประดับเงินเจือต่า 58.33% ผลจากการศึกษาโลหะเงินเจือต่า 58.33 % ที่ประกอบด้วยเงิน (Ag) และทองแดง (Cu) เมื่อ น่ามาเปรียบเทียบกับโลหะเงินสเตอร์ลิง 925 จากการศึกษาเปรียบเทียบพบว่าโลหะเงินผสมเจือต่า 58.33Ag + 36.66Cu +5.01Sn มีค่า Yield Strength 195.2 Mpa Ultimate tensile strength 345.25 MPa Breaking point 301 MPa และ Elongation 61.58 % ซึ่งเป็นอัตราส่วนผสมของแต่ละ ธาตุที่เหมาะสมที่สุด ค่าความแข็งของโลหะเงินเจือต่า 58.33Ag + 41.57Cu + 0.10Sn มีค่าความแข็ง น้อยที่สุด เท่ากับ 93.03 HV ซึ่งปริมาณดีบุก (Sn) ที่ผสมเข้าไปในอัตราส่วน 0.10Sn จะท่าให้โครงสร้าง ของเงินเจือต่า เป็น β-phase เกิดการเปลี่ยนแปลงจาก β phase ที่มีขนาดเล็กลงเป็นโครงสร้าง Eutectic phase ที่มี α-phase และ β-phase ขนาดเล็กและละเอียด ผลจากการวิเคราะห์ส่วนผสมทางเคมีของโลหะเงินเจือต่า 58.33% พบว่าส่วนผสมทางเคมี ของโลหะเงินเจือต่าในแต่ละอัตราส่วนผสมมีสัดส่วนของธาตุใกล้เคียงกับอัตราส่วนผสมจริง จึงท่าให้โลหะ เงินเจือต่าที่ได้ท่าการทดลองมีค่าที่เป็นไปตามมาตรฐานของเครื่องประดับเงินตามมาตรฐานอุตสาหกรรม การผลิตเครื่องประดับทั้งของในประเทศและต่างประเทศ

The purpose of this study was to study and compare good citizenship characteristics of undergraduate of Rajamangala University of Technology Phra Nakhon in 4 aspects: ethics social economy and politics. The undergraduates were classified by gender academic years faculties and achievement. The samples in this research were 389 undergraduates. The study participates selected by stratified random sampling and simple random sampling. The 60 item questionnaires of rating scales was used as the research instrument. Percentage mean standard deviation t - test for independent sample F – test and Scheffe’s test analysis were statistical method to analyze data. The results were as follows: 1. Good citizenship characteristics of undergraduates all aspects were in relatively high levels that ethics was the highest politics was in the lowest rank. 2. There was significant difference for good citizenship characteristics of undergraduates at the 0.05 level among undergraduates in different gender different academic years different faculties and different achievement.

The purposes of this research are to examine the students’ Awareness and Behavior on Mobile Phone Hazardous Waste Management (ABMPWM) comparative studies of dependent variables among the levels of independent variables and their Corresponding correlation’s between their exposure to information and ABMPWM and to yield the appropriate means for managing mobile phone waste. The survey research using self-administered questionnaires was conducted on 450 random samples from 264027 students with study standing at junior and senior high school in Bangkok. The analytical statistical methods used were percentage mode mean S.D.(Standard Deviation) T-Test F-Test One-way ANOVA Analysis Correlation Analysis and Regression Analysis & Prediction Model. The level of the Awareness on Mobile Phone Hazardous Waste Management index (AMPHWM index) was high. The AMPHWM index of men was higher than women and significance difference (p<.05). The group of 13-14 years of age had AMPHWM index at the highest level. The samples of junior high school students had higher AMPHWM index than the group of senior high school students. The group of students who bought the mobile phone themselves had higher AMPHWM index than the others. The group of students belonging the mobile phone with 15000 baht had higher AMPHWM index than the low price. The group of students paying service charge monthly about 301-500 had higher AMPHWM index than the group paying more or less. The group of exposure to information had higher AMPHWM than no exposure to information group. Most of students received information from T.V.. The Awareness on Management of Mobile Phone Waste of the group of exposure to information and the group did not expose to information had correlation to the Behavior on Management of Mobile Phone Waste. The level of the Behavior on Mobile Phone Hazardous Waste Management index (BMPHWM index ) was average. The BMPHWM index of men was higher than women. The group of 13-14 years of age had higher than the others. The samples of junior high school students had higher BMPHWM index than the group of senior high school students. The group of students who bought the mobile phone themselves had higher BMPHWM index than the others. The group of students belonging the mobile phone with more 8001-15000 baht had higher BMPHWM index than the lower and higher price. The group of students paying service charge monthly about 301-500 had higher BMPHWM than the group paying more or less. The group of exposure to information had higher BMPHWM index than no exposure to information group. The group of students received information from internet or electric media had higher BMPHWM index than the group students who received the information from the others.

This research work was to study the chemical release of wood/polyvinylchloride composites (WPVC) affecting the physical and chemical properties of water. WPVC specimens in ratio of PVC and wood (100:100 by weight) were prepared by using twin screw extruder. The water conditions for specimen immersion testing were varied for temperatures of 30-70 oC and specimen immersion time of 0-120 h. The water quality was estimated by measuring pH electrical conductivity turbidity and color of water after immersion of WPVC specimen as comparing with case of PVC specimen. The result suggested that pH values of water slightly decreased with increasing specimen immersion time whereas the change of temperature of water did not affect the pH value. The electrical conductivity remained unchanged with increasing specimen immersion time or temperature except for immersion of WPVC specimens at 70 oC. This might be attributed the weak interfacial bonds between PVC and wood and this led to more easily release the metal ions from additives of PVC. The turbidity and color of water for case of WPVC increased with increasing specimen immersion time whereas those for case of PVC did not change. From the results of water quality testing it indicated that WPVC applications which contact with water are safety. This was because water quality after immersion of WPVC specimen is within the effluent standards of pollution control department.

The purpose of this study was to study and compare services marketing mix factors affecting students’ decision to pursue study at undergraduate level in faculty of science and technology of Rajamangala University of Technology Phra Nakhon in 7 aspects: product price place promotion people process and physical evidence. The undergraduates were classified by gender major subjects educational background department of education achievement and domicile. The samples in this research were 93 undergraduates. The study participates selected by stratified random sampling and simple random sampling. The 84 item questionnaires of rating scales was used as the research instrument. Percentage mean standard deviation t - test for independent sample F – test and Scheffe’s test analysis were statistical method to analyze data. The results were as follows: 1. Services marketing mix factors affecting students’ decision to pursue study at undergraduate level in faculty of science and technology of Rajamangala University of Technology Phra Nakhon all aspects were in moderate levels that price was the highest while process and promotion was in the lowest rank. 2. There was significant difference for services marketing mix factors affecting students’ decision to pursue study at undergraduate level in faculty of science and technology of Rajamangala University of Technology Phra Nakhon at the 0.05 level among undergraduates in different gender different academic years different educational background and different achievement. 3. There was non significant difference for services marketing mix factors affecting students’ decision to pursue study at undergraduate level in faculty of science and technology of Rajamangala University of Technology Phra Nakhon in different department of education and different domicile.