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Abstrak :
Desain suatu roket yang dihasilkan berdasarkan misi tujuan awal sangat mempengaruhi performa aerodinamika yang dimiliki roket tersebut. Dengan berbagai konfigurasi yang dapat dimiliki suatu roket dari profil nose cone, fineness, tail fin, propulsion dan berbagai komponen lainnya, tentunya akan menjadi sebuah tantangan untuk menghasilkan desain yang optimal untuk suatu misi. Dengan demikian dilaksanakan sebuah penelitian yang menguji performa aerodinamika roket terkhususnya drag dan pola aliran udara berdasarkan variasi geometri nose cone yang dibuat dari 4 profil umum. Profil-profil nose cone yang akan diuji dalam penelitian ini adalah conic, power series, tangent ogive, dan elliptical yang akan digunakan pada geometri motor roket FFAR Mk. 40 yang disederhanakan untuk mempermudah penelitian ini. Metode penelitian akan dilakukan secara numerik dengan simulasi CFD (Computational Fluid Dynamics) dengan parameter-parameter yang sudah ditetapkan dan variabel input yang sesuai dengan operasional motor roket Mk. 40. Berdasarkan hasil penelitian yang sudah didapatkan, dapat disimpulkan bahwa nose cone dengan profil conic menhasilkan drag tertinggi dibandingkan 3 profil nose cone lainnya untuk kecepatan subsonik hingga transonik, sedangkan elliptical menghasilkan drag tertinggi untuk kecepatan supersonik. Profil nose cone yang menghasilkan drag terendah dari kecepatan subsonik hingga supersonik dalam penelitian ini adalah profil power series dengan kedua terbaik adalah tangent ogive. ......Design of a rocket is dependent on the mission it is based on which entirely affects the aerodynamic performance of said rocket. With unlimited amount of rocket configurations readily available based on the variation of components and factors such as nose cones, fineness, tail fins, propulsion system and etc., the creation of a optimal rocket for a specific mission is sure to be challenging. In which case, a research is done to analyze the aerodynamic performance of a rocket specifically drag and airflow based on the variation of nose cone geometry made from 4 common profiles. The 4 nose cone profiles which will be studied in this research are conic, power series, tangent ogive, and elliptic which will be then attached to the simplified body of FFAR Mk. 40 rocket motor to ease the study. The research method used are numerical study with computational fluid dynamic (CFD) analysis with various parameters set and input variables based on the operational capabilities of the FFAR Mk. 40 motor. Based on the results of the research, we can conclude that the conic profile produces the most drag than the other 3 profiles during subsonic and transonic speeds and is overtaken by the elliptic profile at supersonic speed. The power series profile produces the least drag from the range of subsonic to supersonic velocity with the second least drag produced from the tangent ogive profile.

Abstrak :
Mineral mangan merupakan salah satu mineral yang paling banyak ditemui di kerak bumi. Sebagian besar produksi mangan dan paduannya di dunia saat ini diserap oleh industri baja. Ferromangan merupakan salah satu logam paduan dengan kandungan mangan yang sangat tinggi, yaitu sekitar 65 - 90%. Sebanyak 90%, ferromangan digunakan untuk menambahkan unsur mangan kedalam material baja untuk memperbaiki sifat-sifat mekanik dari material baja, seperti kekuatan, hardenability, dan ketahanan terhadap aus. Penelitian ini bertujuan untuk mengetahui pengaruh penambahan kadar kokas terhadap keefisienan proses reduksi bijih mangan lokal kadar menengah menjadi produk ferromangan. Proses reduksi dilakukan pada tungku submerged arc furnace tiga fasa dengan kapasitas 100 Kg/Batch dilengkapi dengan tiga buah elektroda grafit. Setiap percobaan menggunakan 30 Kg bijih mangan lokal, 12 Kg limestone, dan kadar kokas yang bervariasi, yaitu 5,5 Kg (18,33%), 7,5 Kg (25,00%), 9,5 Kg (31,67%), dan 11,5 Kg (38,33%). Hasil penelitian menunjukkan bahwa kuantitas dan kualitas produk ferromangan yang dihasilkan meningkat seiring dengan bertambahnya kadar kokas yang digunakan. Dimana kandungan mangan pada ferromangan dan massa/yield produk ferromangan cenderung meningkat. Kandungan mangan pada produk ferromangan tertinggi sebesar 78% pada pengujian menggunakan kokas sebanyak 7,5 Kg (25,00%). Sedangkan massa produk ferromangan tertinggi terdapat pada pengujian dengan menggunakan kokas sebanyak 9,5 Kg (31,67%), yaitu 12,8 Kg. Dan pada penggunaan energi selama proses berlangsung cenderung menurun dengan penambahan kokas, dimana penggunaan energi terendah selama proses reduksi berlangsung pada pengujian menggunakan kokas sebanyak 9,5 Kg (31,67%) sebesar 7,03 KWh/Kg. Namun konsumsi elektroda cenderung meningkat. Sehingga konsumsi elektroda grafit terendah pada saat menggunakan kokas 5,5 Kg (18,33%), yaitu sebesar 0,75 Kg. Berdasarkan aspek ekonomi, pengujian dengan keuntungan tertinggi terdapat pada pengujian menggunakan kokas sebanyak 9,5 Kg (31,67%) yaitu sebesar Rp 62.565 pada tiap satu kali pengujian. ......Manganese is one of the most common minerals in the earth’s crust.Manganese plays an important role in the development of various steel making processes and its continuing importance is indicated by the fact that about 90% of all manganese alloys consumed annually goes into steel production as an alloying element in the form of ferromanganese. Ferromanganese is one of the metal alloys with a high content of manganese, which is about 65 - 90%. Manganese has four functions to steel such as desulphurizing agent, deoxidation agent, enhancing hardness, and wear resistance. This research, studies have been made to obtain the most optimum raw material composition to produce ferromanganese metal based on local medium grade manganese ore with various amount of cokes as its main variable. The process is conducted four times by smelting manganese ore into ferromanganese metal in mini submerged arc furnace (SAF) technology using three graphite electrodes. The process begin with using 30 kg of medium grade manganese ore from Jember, East Jawa-Indonesia, 12 kg of limestone as its fluxing agent, and various number of cokes from 5,5 kg (18,33%), 7,5 kg (25%), 9,5 kg (31,67%), and 11,5 kg (38,33%). Influence of various amount of cokes being used in this study have been investigated. The experiment conducted by increasing number of cokes carried out good results. Higher consumption of cokes will produce bigger number of ferromanganese metal and also the manganese content inside it. The most optimum composition of cokes shown by this study is 9,5 kg (31,67%), producing the biggest number of product at 12,8 kg of ferromanganese and consuming the least energi at 7,03 kwh/kg FeMn. The other result also showed that adding 7,5 kg (25%) of cokes will produce 78% manganese content inside the metal which was the highest manganese content. However, with an increase of cokes, the electrode consumption will also increase. The experiment with 5,5 kg (18,33%) of cokes carried out the least electrodes consumption at 0,75 kg/process. Moreover, to support the optimum raw material composition, economic evaluation has been conducted. The biggest profit is Rp 62.565,-/process for 9,5 kg (31,67%) of cokes.

Abstrak :
ABSTRAK
Aceh Besar District is a filariasis endemic area. This endemic state is strongly influenced by people perception of filariasis countermeasures. This study aimed to determine relation between family perceptions towards health role in filariasis countermeasures using the Health Belief Model. An analytical survey was applied with a cross sectional study approach. The study population was families at three villages that are Lambaro Bileu, Lambaet, and Cot Preh of Kuta Baro Primary Health Care. This represents 1,113 families with a sample of 92 families that were selected using a proportionate stratified random sampling technique. The study instrument was a questionnaire and data were analyzed in a univariate, bivariate, and multivariate. This study showed that the families perceived susceptibility to filariasis disease and the families perception of the benefits from filariasis preventive actions are influenced the health role in filariasis countermeasures (p value = 0.012 and 0.0001). However, the families perception of the seriousness of filariasis disease and the families perception of barriers in filariasis preventive action did not influence the health role in filariasis countermeasures (p value = 0.259 and 0.230). The families perceived benefits of preventive action were the dominant factor related to the families health role in filariasis countermeasures (OR = 12.863, 95% CI = 2.566 until 93.537) after adjusting with perceived susceptibility to diseases (OR = 8.316, 95% CI = 1.769 until 26.949).