Judul: Analisis Kerusakan Komponen dan Produktivitas Gergaji Rantai di Perum Perhutani Divisi Regional Jawa Timur KPH Madiun
Abstrak: The correct usage of chainsaw will increase the logging productivity. In the other hand, the incorrect usage will cause loss such as decline of the productivity, damage to the chainsaw and also causing occupational accident for the operator. The objectives of this research to find out the damage component, the cause of the damage component in chainsaw and also to find out the effect of the damage component towards logging productivity. The data was collected by analyzing the damage component, the cause of the damage chainsaw component and also by analyzing the effect of the damage component towards logging productivity. The analysis of the damage chainsaw component show that the most frequently damage component are chain, spark plug, piston and sprocket. The lack of understanding about the correct maintenance and treatment way for the tools and the usage of non-original part is one of the factors that cause the damage. The damage of chainsaw component can influence the non-effective work hours which result in the size of productivity.
Keyword: Bogor Agricultural University (IPB), productivity, influence, damage, component, chainsaw

Judul: Analisis Biomekanik Operator Chainsaw pada Kegiatan Bucking Pohon Jati di Perhutani KPH Madiun Jawa Timur.
Abstrak: Operator Chainsaw dihadapkan pada faktor fisik di tempat kerja yang meliputi postur janggal saat menebang dan mengangkat beban berat chainsaw. Resiko tersebut apabila tidak diperhatikan dapat menyebabkan pekerja mengalami cedera seperti nyeri, mati rasa, bengkak, kekakuan, dan lain-lain yang secara langsung dapat mempengaruhi produktivitas. Titik ruas tulang belakang (L5/S1) merupakan salah satu titik yang paling rawan terhadap kecelakaan kerja. Hasil analisis biomekanik untuk kegiatan pembagian batang menujukkan postur berdiri membungkuk dan postur menungging termasuk dalam kategori membahayakan bagi pekerja dan perlu dilakukan tindakan perbaikan. Upaya untuk menghindari terjadinya resiko cedera pada titik ruas tulang belakang (L5/S1) yaitu, perlu dilakukan perbaikan terhadap postur kerja operator chainsaw dengan mengubah postur pekerja dan mengganti pemakaian chainsaw yang lebih ringan.
Keyword: antropometri, biomekanik, ergonomika, pembagian batang, postur tubuh

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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