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"Tesis ini meneliti mengenai persentase keterisian microcavity pada cetakan braket ortodontik dengan proses Metal Injection Molding (MIM). Braket ortodontik memiliki microcavity pada bagian sayap dan dasar (base). Berbeda dengan proses pengisian pada MIM konvensional, proses injeksi/pengisian microcavity (μMIM) harus dilakukan dengan cepat. Pada penelitian ini dilakukan simulasi dan injeksi cetakan braket ortodontik dengan MIM terhadap volume feeder. Feeder 1 memiliki volume (luas penampang runner-gate) kecil dan Feeder 2 memiliki volume (luas penampang runner-gate) besar. Simulasi pada Feeder 1 menghasilkan keterisian penuh pada temperatur material 200oC. Simulasi pada Feeder 2 menghasilkan keterisian penuh pada temperatur material 190oC. Aliran material pada injeksi Feeder 1 tidak dapat mencapai gate pada temperatur material 200oC dan tekanan injeksi 1600 kgf/cm2. Aliran material dapat mencapai ujung Feeder 2 pada temperatur material 165~200oC dan tekanan injeksi 1050~1600 kgf/cm2 namun keterisian cavity produk tidak penuh. Simulasi dan eksperimen injeksi memberikan hasil yang berbeda pada keterisian microcavity. Volume feeder yang lebih besar memberikan keterisian microcavity lebih baik.

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This thesis examines the filling percentage of microcavity in orthodontic bracket molds using the Metal Injection Molding (MIM). Orthodontic brackets have microcavities on the wing and base. Unlike the conventional MIM, microcavities on the microinjection (μMIM) were filled rapidly. In this study, simulation and injection of orthodontic bracket molds were carried out on the different volumes of the feeder. Feeder 1 was a small volume feeder (smaller cross-sectional area of runner and gate) and Feeder 2 is a large volume feeder (larger cross-sectional area of runner and gate). Simulations on Feeder 1 produce a complete filling at a material temperature of 200oC. Simulation on Feeder 2 produces complete filling at a material temperature of 190oC. The flow of injected material in Feeder 1 was unable to reach the gate at a material temperature of 200oC and an injection pressure of 1600 kgf/cm2. The flow of injected material in Feeder 2 was able to fill the cavity at a material temperature of 165~200oC and an injection pressure of 1050~1600 kgf/cm2 however one of wing (microcavity) was still incompletely filled. Injection simulations and experiments gave different results on the filling percentage of microcavity. A larger feeder volume provides a better filling percentage of microcavity."

"Isatin (1H-indole-2,3-dione) merupakan senyawa heterosiklik turunan indol yang dapat ditemukan di tumbuhan seperti Isatis tinctoria, Calanthe discolor dan Couroupita guianensi. Isatin dan derivatnya memiliki aktivitas biologis dan farmakologis yang baik. Senyawa derivat isatin berbasis azina telah ditemukan memiliki berbagai bioaktivitas, seperti antibakteri, antijamur, antikanker, antivirus, antiinflamasi, antioksidan, dan sebagai inhibitor korosi. Pada penelitian ini telah dilakukan sintesis derivat isatin aldazin menggunakan variasi aldehid aromatik benzaldehida, 4-hidroksibenzaldehida, dan sinamaldehida sebagai prekursornya. Sintesis ini dilakukan dengan menggunakan katalis protic ionic liquid 1-metilimidazolium hidrogen sulfat [MIM][HSO4] untuk efisiensi waktu. Berdasarkan hasil optimasi diperoleh jumlah katalis dengan kondisi optimum reaksi sebesar 10% mol. Hasil sintesis senyawa isatin aldazin 1 diperoleh persen yield sebesar 84,83%, senyawa isatin aldazin 2 sebesar 50,82%, dan senyawa isatin aldazin 3 sebesar 88,61%. Keberhasilan sintesis diidentifikasi dan dikarakterisasi menggunakan uji titik leleh, kromatografi lapis tipis (KLT), FTIR, UV-Visible, LC-MS/MS, GC-MS, dan NMR. Potensi aktivitas antioksidan senyawa isatin aldazin ditinjau menggunakan metode DPPH dan diperoleh nilai IC50 senyawa isatin aldazin 1 sebesar 4848,84 ppm, isatin aldazin 2 sebesar 15,54 ppm, dan isatin aldazin 3 sebesar 210,32 ppm.

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Isatin (1H-indole-2,3-dione) is an indole derivative heterocyclic compound that can be found in plants such as Isatis tinctoria, Calanthe discolor, and Couroupita guianensis. Isatin and its derivatives have good biological and pharmacological activities. Azine-based isatin derivative compounds have been found to have various bioactivities, such as antibacterial, antifungal, anticancer, antiviral, anti-inflammatory, antioxidant, and corrosion inhibitor. In this study, the synthesis of isatin aldazine derivatives has been carried out using a variety of aromatic aldehydes benzaldehyde, 4-hydroxybenzaldehyde, and cinnamaldehyde as precursors. This synthesis was carried out using a protic ionic liquid 1-methylimidazolium hydrogen sulfate [MIM][HSO4] catalyst for time efficiency. Based on the optimization results, the amount of catalyst with the optimum reaction conditions was 10% mol. The yield obtained from isatin aldazine 1 compound was 84.83%, isatin aldazine 2 compound was 50.82%, and isatin aldazine 3 compound was 88.61%. The formations were identified and characterized using melting point tests, thin layer chromatography (TLC), FTIR, UV-Visible, LC-MS/MS, GC-MS, and NMR. The potential antioxidant activity of the isatin aldazine compounds was evaluated using the DPPH method. The IC50 value of isatin aldazine 1 was 4848.84 ppm, isatin aldazine 2 was 15.54 ppm, and isatin aldazine 3 was 210.32 ppm."

"Sebagian besar braket ortodontik berbahan stainless steel mengandalkan retensi mekanis karena stainless steel tidak membentuk ikatan kimia dengan perekat. Modifikasi base braket ortodontik dengan penambahan mesh dan pengkondisian permukaan dilakukan pada cetakan dengan tujuan peningkatan retensi mekanis dan retensi mikro mekanis. Proses eksperimental dilakukan dengan pembuatan mesh pada cetakan menggunakan teknologi EDM sementara pengkondisian permukaan cetakan dilakukan dengan tiga metode berbeda diantaranya sandblasting dengan aluminium oxide 50 µm, biomachining dengan bakteri acidithiobacillus ferrooxidans, dan etching dengan campuran HNO3 5% (v/v), HF 5% (v/v), 90% aquadest. Hasil penelitian menunjukkan bahwa pembuatan cetakan dengan teknologi EDM memberikan deviasi tidak seragam pada geometri produk akhir dengan diameter bukaan mesh sebesar 408 µm dan diameter wire mesh sebesar 178 µm. Meskipun terjadi deviasi dari desain yang ditentukan, geometri produk akhir masih berada pada rentang desain yang umum digunakan yaitu berkisar antara 75 µm – 700 µm untuk diameter bukaan mesh dan 53 µm – 203 µm untuk diameter wire mesh. Pada penerapan pengkondisian permukaan cetakan, berbagai variasi metode berpengaruh signifikan terhadap peningkatan kekasaran permukaan cetakan, akan tetapi produk akhir tidak dapat mempertahankan kekasaran yang terbentuk setelah melalui proses sintering.

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Most stainless-steel orthodontic brackets depend on mechanical retention because stainless steel doesn’t form a chemical bond with the adhesive. Modification of the orthodontic bracket base by adding mesh and surface conditioning was carried out on the mold with the aim of increasing mechanical retention and micro-mechanical retention. The experimental process was carried out by making a mesh on the mold using EDM technology while the surface conditioning of the mold was carried out by three different methods, including sandblasting with 50 m aluminum oxide, biomachining with acidithiobacillus ferrooxidans bacteria, and etching with a mixture of 5% HNO3 (v/v), 5% HF. (v/v), 90% aquadest. The results showed that the mold making with EDM technology gave a non-uniform deviation in the geometry of the final product with a mesh opening diameter of 408 µm and a wire mesh diameter of 178 µm. Despite the deviation from the specified design, the final product geometry is still within the commonly used design range, which is between 75 µm – 700 µm for the mesh opening diameter and 53 µm – 203 µm for the wire mesh diameter. In the application of mold surface conditioning, various variations of methods have a significant effect on increasing the surface roughness of the mold, but the final product cannot maintain the roughness formed after going through the sintering process."