Polycarbosilane (PCS) fibers have been made using a solvent which is a mixture of N,N-dimethylformamide (DMF) in toluene. Polycarbosilanes (PCS) obtained from NaBond with concentration 1.2 g/ml dissolved in solution toluene and N,N-dimethylformamide (DMF) was stirred gently for 24 h at ambient temperature. DMF was mixed with toluene at ratios 22%, 24%, 26%, 28% and 30%. Electrospinning apparatus (nanoE-Spinning) from NaBond was used. In a vertical electrospinning set up, the solution in a glass syringe delivered to the tip of a 6-gauge (0.5 mm inner diameter) stainless steel needle. The tip to collector distance was adjusted to 100 mm with applied high voltage at 10kV. A stainless steel plate with dimension 100 mm x 100 mm wrapped by aluminum foil was used as collector. The electrospinning non-woven fiber was cured at temperature 200°C (2°C/min), for 1h, 1.5h, and 2h, and fibers with DMF concentration 30% was also pyrolysis at 1000 °C for 3 h in inert atmosphere. The samples were tested and observed with FTIR spectroscopy, and SEM-EDS apparatus. The results showed that PCS fibers can be made from dissolving PCS with toluene with the addition of DMF to increase the polarity of the solvent and the formation of fibers is done by using electrospinning which is supported by the presence of voltage from the outside. Fiber curing is done at 200 °C to evaporate the toluene, the DMF, and resulting stronger fibers than before. The addition concentration of DMF in toluene and curing time will affect the composition of the resulting PCS fiber. Curing time on PCS fibers will affect the composition of solvents such as DMF and Si-H bond on which to assert their PCS fiber cross linking conditions. PCS fiber morphology is known of changes in fiber diameter and fiber uniformity. Smallest PCS fiber average diameter 4.81 μm resulted from 28% DMF with curing time 2 hours and the largest achieved from 22% DMF with curing time 1 hour around 14.22 μm. Composition of pyrolyzed fiber was SiO0.587C0.413, with average density 3.1033 g/cc and average diameter the fiber was 3.06 μm.

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The classification of residential defects (case study: Citra Garden Residence in Indonesia) was studied. This study aims to more satisfied customers. The study begins with the literature review to formulate the classification of house defects. Then classify the defect of house into two, namely the classification of house defects based on period of post hand over, and the classification of house defects based on category of the defects. Further studies followed by dividing the classification of house defects based on period of post-hand over into three parts, namely before hand over period (inviting time), hand over period, and post-hand over period. The next step is to check the complaint report from the customer service in Citra Garden Residence in Indonesia to quantificate the defects of the house. The classification of house defects based on category of the defects divided into two, namely structural defect (minor, moderate, serious), and nonstructural defect (minor, moderate, serious). The next step is also to check the complaint report from the customer service in Citra Garden Residence in Indonesia to quantificate the defects of the house.The results show that complaint hand over in the level minor defect is the highest complaint. Complaint in the serious defect is the lowest complaint.

EVALUATION OF NEUTRON SHIELDING PERFORMANCE OF CD-SS 316L AS A CANDIDATE ALLOY FOR DRY CASK OF RESEARCH REACTOR SPENT FUEL Development of dry casks is necessary to support the national strategy for management of spent fuels. One of the requirements for the dry cask is shielding performance for neutron emitted by the spent fuels to be stored in the dry cask. The objectives of this study are to determine the emitted neutrons by the spent fuel generated from GAS research reactor and to evaluate the neutron shielding performance of Cd-SS316L alloy as a candidate material to be used in dry cask for the spent fuels.  The former was carried out using Origen 2.1 software, while the latter using MCNP5. The result shows that the emitted neutrons by a spent fuel after 5 years discharged from GAS research reactor were 2.81×103 and 3.32×106 n/s for reactor core power of 15 and 30 MW, respectively. Addition of Cd improves the neutron shielding performance of SS 316L. The evaluation of neutron shielding performance of SS 316L with addition of Cd which is the candidate material for dry cask of the spent fuels from the GAS research reactor can be evaluated using Origen 2.1 software for neutron emission, while the neutron shielding performance was evaluated by the simulation using MNCP 5 software. This study shows the Cd-SS 316L alloy can be used for further study to develop the dry cask design for the GAS research reactor.Key words: Neutron shielding, cadmium, stainless steel, spent fuel.

The effect of welding electric current strength on the tensile strength of the 3 kg capacity gas cylinder material welding joint has been studied. The welding carried out in this study is a damping arc welding with variations in electric current of 40A, 60A, 80 A, 100 A, and 120 A. The results show that: The maximum tensile stress is found in the welded specimen with an electric current of 40 A with a tensile strength of 13 kg/mm2, 60 A with a tensile strength of 12 kg/mm2, 80 A with a tensile strength of 28 kg/mm2, 100 A with a tensile strength of 46 kg/mm2. The maximum tensile stress is the test object which is welded with 120 A electric current with a tensile strength of 39 kg/mm2. With the above results, it can be seen that the highest tensile strength of maximum is the sample that is welded with 100 A electric current. The highest maximum tensile strength reaches 46 kg/mm2. The results of observations of micro structures in welded and HAZ matrix areas are Ferrite and Perlite.