Judul: Identifikasi Masalah Disain dan Uji Kinerja serta Operasi Mesin Pemecah Buah Nyamplung
Abstrak: Nyamplung dried fruit with an average weight of 4.15 g, 34 %moisture content and density 0.54 g/cm3 for each kilogram amounts to 242 pieces while the Nyamplung fresh fruit with an average weight of 4.96 g, 42 % moisture content and density 0.61 g/cm3 for each kilogram amounts to 202 pieces. The force required to break a nyamplung dried fruit is equal to 46.90 kgf while for wet nyamplung fruit amounted to 38.42 kgf. Based on engineering analysis conducted on Nyamplung fruit crusher found that the breaker cylinder shaft diameter 20 mm, 330388.15 hours bearing life already have the technical feasibility, but there are some parts that do not have the technically feasible as the blower shaft diameter 9.5 mm, belt length 1,895 m. Power requirements that need to perform the process of splitting is 0.227 hp. While the result of weighting for the performance test with cracking capacity parameters, the percentage of broken and dirt material, and cracking eficiency is obtained that the best treatment for dry matter is at 1.5 cm cylinder gap distance, while the best treatment for wet materials is at 1 cm and 1.5 cm cylinder gap distance. The problems occur during the engine operation is the fraction of nyamplung fruit that accumulate in the serrations wall and the stacking residual fractions of fruit in the sewer.
Keyword: performance test., engineering analysis, Nyamplung fruit crusher

Judul: Design Concept of Rotary Type Nutmeg Mace Machine
Abstrak: Pala merupakan tanaman rempah asli Indonesia dan telah diperdagangkan dan dibudidayakan pada perkebunan rakyat. Pala menghasilkan dua produk bernilai ekonomi tinggi, yaitu biji pala dan fuli atau kembang pala yang menyelimuti biji yang memiliki kandungan minyak atsiri yang tinggi. Salah satu proses penangan pascapanen biji pala, yaitu pengupasan fuli dari biji pala. Usaha yang dapat dilakukan untuk meningkatkan proses penanganan pascapanen pala ini, yaitu merancang mesin yang dapat meningkatkan kapasitas penanganan proses. Tujuan dari penelitian ini adalah membuat konsep desain mesin pemisah fuli biji pala tipe rotari. Penelitian ini menggunakan pendekatan rancangan fungsional dan struktural. Perancangan dilakukan pada komponen hopper, silinder pemisah, dan sistem pengumpanan. Melalui dasar perancangan mesin untuk kapasitas 10 kg, hasil analisis komponen yang diperoleh, di antaranya volume hopper 77,91 L, silinder pemisah berdiameter 0,29 m dengan panjang 0,5 m, sistem pengumpanan menggunakan screw conveyor dan sistem transmisi daya listrik 0,75 kW menggunakan sabuk dan puli., Nutmeg is an Indonesian native spice plant and has been cultivated and traded by smallholder plantations. Nutmeg has two high economic value products, namely nutmeg seeds and nutmeg mace that envelop seeds and have high content of essential oils. One of nutmeg post-harvest process is peeling nutmeg mace from nutmeg seeds. Efforts should be made to improve this post-harvest process by designing a machine that can increase peeling process capacity. The purpose of this research was to develop a design concept of design of rotary type nutmage mace peeling machine. This research was conducted using functional and structural design approach. Design was carried out on hopper component, separator cylinder, and feeding system. Base on 10 kg per batch of designed machine capacity, the results of the analysis of components obtained were 77,91 L of hopper volume, 0,29 m of diameter and 0,5 m of length for separtor cylinder dimension, screw conveyor as feeding system, and belt and pulley as transmission system of 0,75 kW electric power.
Keyword: nutmeg mace, hopper, peeling machine, screw conveyor, separator cylinder

Judul: Pengaruh vaksinasi terhadap dinamika populasi pada model SIR (Susceptible-Infected-Recovered)
Abstrak: SIR model can be used to model the spread of diseases in a closed population based on certain assumptions. In this research, the SIR model is formulated by including the factor of vaccination. As the result, the model has been shown to have two equilibrium points, i.e. disease free and endemic equilibrium. A simulation study is carried out to illustrate the model. The results show that some equilibrium points are asymptotically stable. Moreover, a minimum level of vaccination has been defined. For the vaccination level less than the minimum level, increase in the vaccination level results in decrease of the proportion of infected individuals in the corresponding equilibrium point. On the other hand, for the vaccination level greater than the minimum level, increase in the vaccination level results in decrease the proportion of susceptible individuals in the corresponding equilibrium point. Furthermore, when vaccination level is greater than the minimum level, it is found that the time needed for the disease to extinct is shorter.
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