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Abstrak :
The type of stainless steel that is most commonly used in bone implants is austenitic 316L stainless steel, which has an excellent corrosion resistance and high strength. The Center for Materials Technology, BPPT, in cooperation with a local industry, is currently undertaking research into integrating, refining and alloying processes for the production of medical grade 316L stainless steel, using raw material originating from the ferronickel of Pomalaa. Natural resources of ferronickel, one of the main raw materials for stainless steel, are locally available in Indonesia. Other alloy metals such as steel scrap, ferro chrome and ferro molybdenum are bought in the market. The charging calculation is done by computer-aided simulation, before the melting processes are carried out. The melting facility used is an induction furnace of 250 kg capacity, following the procedures commonly used in the industry. Chemical composition analysis is done by a spectrophotometer. Tensile and hardness tests are conducted, and a microstructure observation is also carried out using an optical microscope and a scanning electron microscope. The selection of raw material inputs and refining and annealing processes affect the quality of the alloy. In our study, we found various forms of oxide inclusions in the stainless steel microstructure: triangular, hexagonal and spherical. The tensile strength of the specimen of 316L stainless steel casting materials was influenced by the presence of oxide phases.

Abstrak :
Plastik yang terbuat dari bahan-bahan petrokimia sulit diuraikan oleh mikroba dan pada akhirnya terjadi penumpukan dan pencemaran lingkungan. Oleh karena itu dibutuhkan pengembangan plastik biodegradable yang mudah diuraikan. Kitosan merupakan salah satu polimer alami yang mempunyai kemampuan sebagai agen antimikroba. Dengan penambahan bahan lain seperti nanoselulosa dan agen antimikroba lain diharapkan dapat menyempurnakan sifatsifat dari kitosan tersebut. Dalam penelitian ini telah berhasil dibuat plastik film dari bahan kitosan dan nanofibril selulosa dari serat daun nanas dengan penambahan minyak kencur sebagai agen antimikroba. Nanofibril selulosa (NFS) yang digunakan dalam penelitian ini diisolasi dari serat daun nanas dengan perlakuan kimia dan mekanik menggunakan alat Ultra Fine Grinding. Penelitian ini bertujuan untuk mempelajari pengaruh penambahan NFS terhadap sifat mekanik, laju transmisi uap air, sifat optik dan thermal serta efek penambahan minyak kencur terhadap sifat antimikroba dari film komposit. Pengamatan TEM terhadap nanofibril selulosa (NFS) menunjukkan ukuran diameter fibril sekitar 20 nm. Penambahan NFS meningkatkan nilai kuat tarik, meningkatkan kristalinitas dan menurunkan nilai laju transmisi uap air dari film komposit kitosan. Selain itu juga dilakukan analisa XRD, UV-Vis, TGA, SEM dan FTIR terhadap film komposit. Selanjutnya dilakukan uji aktivitas antimikroba terhadap film komposit yang telah ditambahkan minyak kencur. Dari pengujian tersebut dihasilkan daya inhibisi pada bakteri E. coli dan S. aureus tersebut meningkat dengan penambahan minyak kencur ke dalam film komposit.

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Plastics made from petrochemiccal materials are difficult to degraded by microbes and ultimately build up and pollute in the environment. Therefore, we need to developed a biodegradable plastic which is easy to degradate by nature. Chitosan is one of the natural polymer that has the ability as an antimicrobial agent. The addition other material such as nanoselulose and other antimicrobial agents, it is hoped that it can improved the properties of chitosan film. In this research, we have successfully made film plastic from chitosan and nanofibril cellulose material from pineapple leaf fibers with the addition of Kamepferian Galanga L essensial oil as an antimicrobial agent. Nanofibril cellulose (NFS) used in this study was isolated from pineapple fiber with chemical and mechanical treatments using Ultra Fine Gridning tool. This research is to study the effect of NFS addition to mechanical, optical, water vapour transmission rate, thermal properties and also the effect of Kamepferian Galanga L essensial oil to antimicrobial properties of composite film. The TEM observation of cellulosic nanofibrils (NFS) shows fibril diameter is around 20 nm. The addition of NFS increases the tensile strength, crystallinity and water vapor transmission rate of the chitosan composite film. In addition analysis of XRD, TGA, SEM and FTIR of composite films were also performed. Furthermore, the antimicrobial activity has been conduct the composite film with the addition of Kamepferian Galanga L essensial oil. From the test the inhibitory zone of E. coli and S. aureus bacteria is increased by adding Kamepferian Galanga L essensial oil into composite film.