A study has been conducted on the extract concentration effect of Maja Peel as an inhibitor of low carbon API 5L in corrosive medium of NaCl 3% and H2SO4 3%. The soaking process of low carbon API 5L was done for 35 days with variation of addition inhibitor concentrations at 0%, 0,4%, 0,5%, 0,6%, 0,7%, and 0,8%. The testing of Corrosion rate is done by weight loss method. The results showed that the highest corrosive rate in corrosive medium of NaCl 3% and H2SO4 3% was at 0% which is inhibitor concentration, 0,06 x 10 4 mm/y and 16,55 x 10 4 mm/yconcentration. Meanwhile, the lowest corrosion rate at 0.8% inhibitor concentration for corrosive medium ofNaCl 3% and 0.5%for H2SO43% corrosive medium. Hence, the greatest effectiveness of corrosion occurs at the concentration of 0.8% in a corrosive medium of NaCl 3% with effectiveness of 85,71% and 0.5% in corrosive medium of H2SO4 3% with the effectiveness of 79.35%. The characterization result of X-Ray Diffraction (XRD) shows that the phase formed is pure Fe. Characterization of Scanning Electron Microscopy (SEM) showed uneven clusters and smaller sizes, holes and cracks also with less than 0.8% inhibitors for corrosive medium of NaCl 3% and 0.5% for corrosive medium of H2SO43% compared with 0% inhibitor of maja peel extract on corrosive medium ofNaCl 3% and H2SO4 3%. Characterization of Energy Dispersive Spectroscopy (EDS) in samples with corrosive medium of H2SO43% obtained the element S (Sulfate).Keywords: low carbon API 5L, the extract of maja peel, corrosion inhibitor, NaCl, and H2SO4.Abstrak. Telah dilakukan penelitian mengenai pengaruh konsentrasi ekstrak kulit buah maja sebagai inhibitor pada baja karbon API 5L dalam medium korosif NaCl 3% dan H2SO4 3%. Perendaman baja karbon API 5L dilakukan selama 35 hari dengan variasi konsentrasi penambahan inhibitor ekstrak kulit buah maja 0%, 0,4%, 0,5%, 0,6%, 0,7%, dan 0,8%. Pengujian laju korosi dilakukan dengan metode kehilangan berat. Hasil penelitian menunjukkan laju korosi terbesar pada medium korosif NaCl 3% dan H2SO4 3%adalah pada konsentrasi inhibitor 0% , yaitu sebesar 0,06 x 10 4 mm/y dan 16,55 x 10 4 mm/y. Sementara, laju korosi terendah yaitu pada konsentrasi inhibitor 0,8% untuk medium korosif NaCl 3% dan 0,5% untuk medium korosif H2SO4 3%. Sehingga efektivitas korosi yang paling besar terjadi pada konsentrasi 0,8% pada medium korosif NaCl 3% dengan efektivitas sebesar85,71%, dan 0,5% pada medium korosif H2SO4 3% dengan efektivitas sebesar 79,35%. Hasil karakterisasi X-RayDiffraction (XRD) memperlihatkan bahwa fasa yang terbentuk adalah Fe murni. Karakterisasi Scanning Electron Microscopy (SEM) memperlihatkan cluster (gumpulan) tidak merata dan ukuran lebih kecil, lubang (hole) dan retakan (crack) juga lebih sedikit dengan inhibitor 0,8% untuk medium korosif NaCl 3% dan 0,5% untuk medium korosif H2SO4 3% dibandingkan dengan inhibitor 0% ekstrak kulit buah maja pada medium korosif NaCl 3% dan H2SO4 3%. Karakterisasi Energy Dispersive Spectroscopy (EDS) pada sampel dengan medium korosif H2SO4 3% didapatkan uns...

The aim of this research is to make wollastonite from silica obtained from rice husk ash and commercial calcium carbonate using the solids reaction method. The DTA-TGA results show mass due to the evaporation of H2O and the decomposition of CaCO3 into CaO along with the calcination temperature, in addition, the DTA results also identify the formation of the β-CaSiO3 phase and the α-CaSiO3 phase. The XRD results of wollastonite obtained were dominated by the β-CaSiO3 phase and the minor phase was α-CaSiO3 this was indicated by the peak intensity of the β-CaSiO3 phase which was higher than the peak intensity of the α-CaSiO3 phase. the second phase in wollastonite is also the result of FTIR results through the analysis of the Si-O-Ca functional group in each wollastonite sample. In addition, the results of the SEM analysis showed the shape of the spheroidal particles (spherical) with an average grain size of 0.19 m, 0.35 m and 0.68 m for the calcination temperatures of 900 oC, 1000 oC and 1100 oC, respectively. The results of this study indicate that the manufacture of wollastonite from the basic ingredients of rice husk silica and commercial calcium carbonate has potential as an alternative material for the manufacture of wollastonite.

The research has been done in the field of Field Work Practice to synthesize superconductors Bi1,6Pb0,4Sr2Ca2Cu3O10+x for Meissner test using solid reaction method. The objective of this research is to make superconductor Bi1,6Pb0,4Sr2Ca2Cu3O10 x with solid reaction method and to know the result of superconducting character of Bi1,6Pb0,4Sr2Ca2Cu3O10 +x based on Meissner test. From the results of Meissner test that has been done on this superconductor sample looks super magnet and superconductor repel each other rejects or super magnet drift.Sehingga it can be concluded that the sample has a strong Meissner effect. From the results of Tc test using cryogenic tools obtained Tc Zero temperature of 103.4 K and Tc Onset of 116.67 K. From the data obtained it can be concluded that the sample has reached phase 2223.

The purpose of this study was to determine the effectiveness of developing interactive media on solar system material in improving student learning outcomes. The method used is the Research and Development method (research and development). The stages of development in this study began with analyzing needs, designing, making interactive media, then applying it in learning and then testing student learning outcomes. Data analysis was carried out using descriptive percentages and one sample test for student completeness. This can be seen from the validation results of material experts who stated "very feasible", while media experts for the media aspect were declared "very feasible", and for the language aspect it was declared "very feasible". Whereas for the student response questionnaire it was declared "very interesting" and for the educator's response questionnaire it was stated "very interesting". The developed media can also improve student learning outcomes by obtaining a percentage of 92.30% with very good qualifications.