จำนวน Repository ( 20 )

Mechanical Properties of Silica-Based Geopolymer Composites Cured at Ambient Conditions in Accordance with Size-Independent Method
Mechanical Properties of Silica-Based Geopolymer Composites Cured at Ambient Conditions in Accordance with Size-Independent Method

In this paper silica-based geopolymer matrix reinforced composites containing approximately 35 50 or 55 wt.% of carbon (HTS 5631 1600tex 24K TohoTenax) advanced basalt (BCF13-2520tex KV12 Int Basaltex) or electrical grade glass (E-glass: E2400P192 Saint-Gobain Vetrotex) roving fibers respectively were synthesized and fabricated at ambient conditions. The flexural properties of the resulting composites which are high toughness: the shear stress plays here a greater role in compared with other ceramic matrix composites were determined on a universal testing machine under three-point bending mode in accordance with novel size-independent method which based on testing specimens at different scale of sample height (H) to span length (L) ratios; The basic principles of the new size-independent approach are presented as well. Microstructures of composites were analyzed by means of scanning electron microscope (SEM) on perpendicular sections the images show the adhesion between the fibers and geopolymer matrix are very good and micro-cracks on both cross-sections and surfaces of geocomposites are determined as inborn defects of inorganic matrix composites.

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สมบัติทางเคมีกายภาพ ทางกล และทางความร้อนของฟิล์มบริโภคได้จากแป้งมันเลือด
สมบัติทางเคมีกายภาพ ทางกล และทางความร้อนของฟิล์มบริโภคได้จากแป้งมันเลือด

Man Lueat (Dioscorea alata) flour is a biopolymer material that can be formed into an edible film. It can be contacted directly with food consumed and naturally biodegraded. The aims of this research were to study the effect of physicochemical mechanical and thermal properties of edible film from Man Lueat flour. The film forming solution was prepared by Man Lueat flour at 4% w/w. The glycerol was used as a plasticizer. It was studied at 3 different levels; 30 40 and 50% w/w of Man Lueat flour. The film forming solutions were formed using the solution casting method and dried at 50 °C for 16 h. Results showed that the glycerol content at different levels of the edible film from Man Lueat flour had no effect on the thickness color transparency and elongation at break. However the moisture content water solubility swelling property and water vapor permeability of the film tended to increase when increasing the glycerol content. In contrast the Young’s modulus and tensile strength of films tended to decrease significantly when the glycerol content increased. Thermal properties were found that decomposition temperature of films occurred 2 stage; the first stage occurs between 50 to 130 ° C and the second stage occurs between 263 to 315 ° C. The analysis of FT-IR showed that the different levels of glycerol affected the structure of the film (3278 cm-1). Therefore the edible film from Man Lueat flour can be applied as a food packaging material to protect the quality of food products.

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การศึกษาพัฒนาส่วนผสมโลหะทองขาว 6k สำหรับการผลิตตัวเรือนเครื่องประดับ
การศึกษาพัฒนาส่วนผสมโลหะทองขาว 6k สำหรับการผลิตตัวเรือนเครื่องประดับ

This Research is to Study the Development of 6k White Gold Alloys for Jewelry Production. The Influence of Admixtures on Mechanical Properties was Investigated (Tensile Strength and Hardness) of 6k White Gold Alloys at Various Composite Ratios. The Results of the Experiments Show that the Chemical Composition of 6k White Gold Alloys is Slightly Different when Compared with the XRF (X-ray Fluorescence Spectrometers). Compare the pre and Post-Melting Quantities. Test results of Mechanical Properties of Test Pieces. The Tensile Strength of the 6k Gold Alloy is 25% Au+46%Ag+8%Cu+3%Zn+18%Pd The Highest Value was 1.14 kN / mm2 the Lowest Percentage was 64% and the Hardness was 259.87HV. The Result of this Test is that the Mechanical Properties of the Material are Brittle Material. When the Mold is Formed the Fracture and Forming will be Difficult. 25%Au+42%Ag+12%Cu+3%Zn+ 18%Pd 25%Au+50%Ag+4%Cu+3%Zn+18%Pd and 25%Au+54%Ag+0%Cu+3%Zn+ 18%Pd Tensile Strength in the Range of 0.66-0.70 kN / mm2 Percentage of Elongation in the Range of 84-90% and Hardness of 277.60 244.60 and 186.73HV Respectively. The Mechanics will Show that the Alloys of White Gold 6k 25%Au+54%Ag+0%Cu+3% Zn+18%Pd Have Similar Tensile Strength. The Maximum Percentage of Elongation is 90% and the Minimum Hardness is 186.73HV. It is Suitable for Forming because it has Ductile Material. This is a Good Mechanical Property in the Metal Forming Machine.

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การปรับปรุงความเหนียวและความทนแรงกระแทกของพอลิแลกติกแอซิดโดยการใช้น้ำมันถั่วเหลืองที่ผ่านการดัดแปรและเส้นใยธรรมชาติ
การปรับปรุงความเหนียวและความทนแรงกระแทกของพอลิแลกติกแอซิดโดยการใช้น้ำมันถั่วเหลืองที่ผ่านการดัดแปรและเส้นใยธรรมชาติ

This research work was to study the improvement of toughness and impact resistance of polylactic acid (PLA) with modified soybean oil (MSBO) and palm fiber (PF). The detail of this work was divided into three parts. The first was to find the suitable condition for modification of soybean oil with ozonolysis. The second and last parts were to study the effects of MSBO and PF contents on the properties of PLA respectively. For oil modification the reaction times were varied from 0 to 3 hours and the chemical changes in molecules of soybean oil were investigated by Nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopies. The result suggested that the most suitable condition for ozonolysis reaction was 2 hours considering the decrease in double bond between carbon atoms and the increase in hydroxyl group into molecular structure of MSBO. For the effect of MSBO content on mechanical properties it was evaluated by tensile and impact testing. Differential scanning calorimeter (DSC) and scanning electron microscope (SEM) were used for thermal and morphology analyses. The result showed that elongation at break and impact strength of modified PLA by MSBO increased about 89 and 25 % compared to those of neat PLA respectively. MSBO act as the efficient plasticizer for PLA considering the conversion of fracture behavior from brittle to ductile good dispersions of MSBO droplets in PLA and the decrease of glass transition temperature (Tg) with addition of MSBO. The addition of PF improved the impact strength of modified PLA. Strong interfacial bonding between PLA and PF indicated MSBO being both coupling agent for PLA and natural fiber and plasticizer for PLA. For migration test it was found that contents of released heavy metal and migrated chemical from specimens of PLA and PLA/PF composite were under the criteria according to Notification of the Ministry of Public Health (No. 295) B.E. 2548.

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Permanent-magnetic-field, bean sprout, neodymium welding process
Permanent-magnetic-field, bean sprout, neodymium welding process

The objective of this research is to investigate microstructure and mechanical properties of brass welded by diffusion welding process. The diffusion welding (DW) of brass welded over lap joints bonding parameters were pressure at temperature 500 650 and 800 0C contact pressure of 12 MPa and holding time for 60 minutes respectively. The microstructure mechanical properties and behaviour during bonding were investigated. The results show that in weld zone (Bond Line) diffusion of atom the brass significantly. The mechanical properties after diffusion welding process increased higher temperature

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