จำนวน Repository ( 27 )
Strength, porosity and corrosion resistance of ternary blend Portland cement, rice husk ash and fly ash mortar
This paper presents a study of the strength porosity and corrosion resistance of mortars made with ternary blends of ordinary Portland cement (OPC) ground rice husk ash (RHA) and classified fly ash (fine fly ash FA). Compressive strength porosity and accelerated corrosion with impressed voltage (ACTIV) were tested. The results show that the use of ternary blend of OPC RHA and FA produces mortars with improved strengths at the low replacement level with RHA and FA and at the later age in comparison to that of OPC mortar. The porosity of mortar containing pozzolan reduces with the low replacement level of up to 20% of pozzolan but increases with the 40% replacement level. The chloride induced corrosion resistance of mortar as measured by ACTIV is however significantly improved with the use of both single pozzolan and the ternary blend OPC RHA and FA. The corrosion resistance of ternary blend mortar is higher than that of mortar containing single pozzolan. The use of ternary blend OPC RHA and FA is very effective in enhancing chloride induced corrosion of mortar.
การทดสอบความล้าของเหล็กกล้า S45C แบบหมุนดัดปลาย
This research is to test the fatigue endurance of the material by using end bending of specimen. The testing material is S45C steel and forming to the standard size for testing. The specimens with a diameter of 8 mm required a different bending moment. It was found that the large bending moment affects the fatigue of the specimen. The specimen quickly damaged due to the high bending stress and there were a small number of load cycles. If the bending moment acting on the specimen was reduced to the bending stress decreased and the number of load cycles increasing. It was shown that the bending stress and the magnitude of the bending moment affected the fatigue of the material. Also the appearance of damage marks of the specimen will have a flaw around the fracture surface. Then the flaw will be enlarged until the specimen will be damaged by fracture.
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.
การศึกษาพัฒนาเพิ่มมูลค่าของโลหะเงินสเตอร์ริงผสมแพลเลเดียมเพื่อเพิ่มคุณสมบัติต้านความหมองสำหรับอุตสาหกรรมเครื่องประดับ
The study of silver metal used in the non-plated jewelry industry was found to be dull or black but it was a basic feature of silver. To react with air easily in Thailand. The hot weather must be maintained regularly. The concept that we can study the development of silver metal with resistance to tarnish to slow down will have a positive effect on the jewelry industry. The team has developed a concept to bring other elements to meet the potential. The element used here is palladium (Pd) because the palladium is in the same group as the nickel and platinum groups in the periodic table. It is a metal (Nobel Metal) which is very durable corrosion. Usually white is natural and when used to polish the skin is glistening and in most cases in the jewelry industry is often used as part of the alloy such as making the natural gold color close to the platinum. The authors performed the experiments by introducing silver metal with palladium in an appropriate ratio and tested it with artificial stone. And save the record. It is divided into 4 periods of 5-20 days in normal temperature. The results of the study showed that 92.5% copper 6.8% and 0.7% palladium had a shade of L value of 59% over 20 days. It can be used to produce silver jewelry at a lower tarnished rate. In the jewelry industry
ความสัมพันธ์ของการกระจายตัวของสารป้องกันกำจัดศัตรูพืชตกค้างในดินเพาะปลูกข้าวและระดับการปนเปื้อนในเมล็ดข้าว
The effect of pesticides on farmers and the distribution of residual pesticides in rice plants and rice grain was studied in rice farming area covered in Samchuk district Suphanburi province. The situation and health effects related to pesticides was conducted using an individual interview and filled-form questionnaire with 126 samples. The participants were male of 68.3% and female of 31.7%. Educational level of participants was to be 36.5% and 24.6% for primary and elementary levels respectively. One-third of farmers (33.3%) reported a monthly income in the range of 5000 to 10000 Baht. A quarter of farmers (25.4%) got higher a monthly income with 10001 to 15000 Baht. Family members was found to be 4 persons (54%) 5 persons (19.8%) and over 5 persons (11.1%). All participants concerned the behavior and perception related pesticides for their highly toxicities and extremely dangerously death. A half of herbicide (50%) was glyphosate. Seriously paraquat (commercial name of Gramoxone) was found to be 22%. On the other hand the most of insecticide (55%) was an abamectin and carbofuran (commercial name of Furadan) was found to be 15%. A 20 samples of rice plants and rice grain was collected by random sampling. The residual carbofuran and glyphosate in rice plants and rice grain was determined using standard method. It was found that carbofuran was found in the range of ND-0.05 μg/kg and ND-0.08 μg/kg for rice plants and rice grain respectively. Glyphosate was found in the range of ND-0.26 μg/ kg and ND– 0 . 2 2 μg/ kg for rice plants and rice grain respectively. The residual levels of carbofuran and glyphosate in rice plants and rice grain depended on a spray period time their decomposition and the concentration of carbofuran and glyphosate. The residual levels of carbofuran and glyphosate did not significantly quantitative correlation between rice plants and rice grain.