THE EFFECT OF KAOLINITE ON TENSILE AND FLEXURAL BEHAVIOR OF SALACCA FIBER - REINFORCED EPOXY/KAOLINTE HYBRID COMPOSITES

The use of filler in composite materials is emerged as a result of increasing demand for the advancement inmaterial properties to satisfy the market necessities. This study presents the effects of kaolinite inclusion ontensile, flexural and characteristics of Salacca fiber/kaolinite reinforced composite laminates. The laminateswere fabricated by hand layup and moulding. Kaolinite particles having four different weight fractions as 1, 3, 6and 9by volume percentages were used for fabrication of composite laminates. The specimens were preparedaccording to ASTM D638 and D790 standards for tensile and flexural tests, respectively. Results obtained fromspecimens having Kaolinite particles showed the serious improvement on the tensile strength, flexural modulusand flexural strength values compared to specimens without kaolinite inclusion.The use of filler in composite materials is emerged as a result of increasing demand for the advancement inmaterial properties to satisfy the market necessities. This study presents the effects of kaolinite inclusion ontensile, flexural and characteristics of Salacca fiber/kaolinite reinforced composite laminates. The laminateswere fabricated by hand layup and moulding. Kaolinite particles having four different weight fractions as 1, 3, 6and 9by volume percentages were used for fabrication of composite laminates. The specimens were preparedaccording to ASTM D638 and D790 standards for tensile and flexural tests, respectively. Results obtained fromspecimens having Kaolinite particles showed the serious improvement on the tensile strength, flexural modulusand flexural strength values compared to specimens without kaolinite inclusion

PRODUCTION OF URANIUM-MOLYBDENUM ALLOY AS A CANDIDATE FOR NUCLEAR RESEARCH REACTOR FUEL

PRODUCTION OF URANIUM−MOLYBDENUM ALLOY AS A CANDIDATE FOR NUCLEAR RESEARCH REACTOR FUEL. Research and development on high density uranium for nuclear research reactor fuel is still in progress. Uranium-molybdenum alloy is one of the strongest candidates of nuclear research reactor fuel material. The properties and characteristics of U-Mo alloy is of important consideration for the selction of the fabrication techniques for the production of  the fuel. In this work, uranium-molybdenum (U-Mo) alloys with varied molybdenum content have been produced succesfully by arc melting technique. The molybdenum content variations were 7 %wt, 8 %wt, 9 %wt and 10 %wt Mo. The melting process was done 5 times to achieve homogenization. Metallographic micrograph shows the presence of dendritic structure. XRD examination result affirms the presence of 2 phases of γ-U phase and d-U2Mo phase. Microhardness Vickers test shows higher hardness value for Uranium-molybdenum alloy with higher molybdenum content. Keywords: U−Mo alloy, research reactor, fuel

Thermal Conductivity and Bending Strength of Porous Mullite Ceramics Made by PFA Method Using Corn Starch

Porous ceramics are widely used in filter, thermal insulation and acoustics applications. This research aims to produce porous mullite ceramics by PFA (Pore-Forming Agent)method using corn starch as the agent. Various contents of corn starch of 0, 5, 10, 15, 20 and 25 % weight were added to kaolin powder. Each composition was uniaxially pressed to produce green body. The green body of monolithic kaolin was pressureless sintered in air at various temperatures of 1000, 1100, 1200, 1300, 1400 and 1450 oC for two hours. Temperature of 1450 oC was chosen for producing porous mullite ceramics. Relative density, bending strength and thermal conductivity were measured on the sintered body. The results show that the porosity of the mullite ceramics increases with increasing corn starch contents. The bending strength and thermal conductivity of the porous mullite ceramics decrease with increasing porosit

Mechanical, morphological, and thermal characteristics of epoxy/glass fiber/cellulose nanofiber hybrid composites

Generally, glass fiber-reinforced polymer composites are made in the form of laminated composites. Due to the weak adhesion between the fiber and the polymer matrix, failure in the form of delamination often occurs. To overcome delamination, the incorporation of very low content of nanomaterials has been considered. The effect of cellulose nanofibers (CNFs) addition on the mechanical, morphological, and thermal properties of the epoxy/glass fiber/CNFs hybrid composites was evaluated. The hybrid composites containing 1 and 2 wt CNFs were prepared by hand lay-up followed by vacuum bagging and compression. The mechanical characteristics of the composites were investigated through tensile, flexural, short beam shear, and impact tests, while thermal stability was evaluated by thermogravimetric analysis (TGA). The results revealed that with the presence of 1 wt CNF, the tensile strength and modulus of the epoxy/glass fiber composites were enhanced by 9 and 10, respectively whereas the flexural strength and modulus were increased by 16 and 6, respectively. SEM observations showed the presence of a strong CNF interaction with glass fiber and a thin layer of epoxy interphase around the glass fibers. Moreover, the introduction of 1 wt CNF to the epoxy/glass fiber composite improved the interlaminar shear strength by 11, while the thermal stability did not change. © 2022 The Author

Preparation of Porous Hydroxyapatite as Synthetic Scaffold Using Powder Deposition and Sintering and Cytotoxicity Evaluation

This study prepared porous hydroxyapatite (porous HA) as synthetic scaffold and find out chemical properties, porosity, compressive strength and cytotoxicity properties. Porous HA was prepared by powder deposition and sintering from HA-PMMA mixed powder. Porous HA characterizations were conducted by XRD, XRF, SEM-EDX and mercury porosimetry analysis. In vitro cytotoxicity testing of porous HA was conducted by MTT method using vero cells. Porous HA has porosity on the interval 62.79 to 69.67% and compressive strength on the interval 1.53 to 3.71 MPa. Optimal porous HA has porosity is 62.79% with compressive strength is 3.71 MPa. Mercury porosimetry analysis showed that optimal porous HA has interconnective porosity up to 88.25% with pore size on the interval 0.05-355 μm and median pore is 52.64 μm. There was no significantly difference in the death percentage of vero cells caused HA powder and optimal porous HA (p= 0.158) but concentration of optimal porous HA were significantly effect on the percentage of vero cells death (p=0.003)

STUDI SIFAT FISIS DAN KONDUKTIFITAS TERMAL KOMPOSIT CLAY/ALUMINA UNTUK APLIKASI FIRE BRICK

Refractory ceramic material which is widely used in high temperature process without physical and crystal changes. and it usually contains 25.4 � 41.9% of alumina. This research aims to study sintering temperatures and alumina on its addition on clay ceramic on physical, mechanical, and thermal properties of clay/alumina composites. The clay was obtained from Central Sulawesi containing (weight%) 27.45% Al2O

The Effect of Thermal Shock on Bending Strength of Zirconia Ceramics

This research aims to investigate the effect of thermal shock on bending strength of zirconia stabilized with 3% mol Yttria known as 3Y-TZP (Tetragonal Zirconia Polycrystal stabilized with 3 %mol Yttria). The zirconia powder with mean particle size of 0.2 - 2 µm was obtained from Good fellow UK. Zirconia powder was uniaxially pressed with a pressure of 100 MPa to produce cylindrical green body with a diameter of l5 mm and thickness of 8 mm and green body specimens of rectangular cross-section bar (8x5x50 mm3). The cylindrical green body was pressureless sintered at various temperature of 1250, 1300, 1350, 1400 and 1450 oC for 1 hour. The density of each sintered specimens was measured using Archimedes method. It was found that 1450oC was the best sintering temperature. The rectangular green bodies were then pressureless sintered in a furnace at temperatures 1450 oC for 1 hour with a heating rate of 5oC/min. The sintered samples were polished. Group of the sintered samples were then heated up with a heating rate of 5 oC /minute to various temperature of 25, 225, 275, 325 and 425 oC with a holding time of 1 hour. They were then thermal shocked by rapid cooling (quenching) to a water media with a temperature of 25 oC. The strength of samples was evaluated using four point bending test. The results shows that the thermal shock resistance of the specimen is 200 oC and 250 oC where the bending strength decreases drastically