Judul: Optimisasi Waktu Penggantian Komponen pada Mesin Produksi Benih Padi di PT Sang Hyang Seri
Abstrak: Key points in the maintenance of seed production machine is the analysis on economical machine lifetime, routine engine maintenance, spare parts replacement, and purchase a new machine. Such activities need to be analyzed can to produce a minimum of cost production. This study was conducted to observe the seed production process, analyze the critical level of the components on seed production machines, and to analyze the activities of maintenance and replacement of components on seed production machines. The research method is involving the identification of the seed production machines, i.e. kind of machines, need for engine power, engine speed, engine capacity, efficiency of the engine, and the maintenance history. Data were obtained from direct measurements in the field and on from the company's engine conditions records from 1991 to 2011. Data were analyzed with assessment of critical components (ECR) and optimization of time for component replacement (CoTR). The results showed that conveyors are the most critical components in the system of seed production machine maintenance. CoTR of the components are ranging from 0.87 to 3.14 years, and it can be implemented with scheduled replacement of 6 months, 1 year, 2 years and 4 years, respectively. There is also a need to improve the recording procedures of engine maintenance activities by PT Sang Hyang Seri which include the damage and the treatment carried out.
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Judul: Rancang Bangun Sistem Informasi Manajemen Pengendalian Suku Cadang untuk Pemeliharaan Preventif Mesin Produksi PT Sang Hyang Seri
Abstrak: The demands of seeds with good quality, precise production, and sufficient amount implies seed production activities of PT Sang Hyang Seri (SHS) should always be fast and optimal. Production factors that determine the outcome is, among others, the readiness of equipment for operation with excellent condition. Preventive maintenance can prevent damage of the machines that occurred on the machines before use. Good preventive maintenance can be achieved by control of parts that support the procurement needs of all preventive maintenance activities of the machine. Manager of the company plays an important role to always supervise the activities of the control and maintenance of machine in factory. Therefore, research is needed to design a management information system (MIS) that can help control the activities of preventive maintenance spare parts in machinery. The purpose of this study is to analyze the need for the user of the MIS, then designing system that can make activity of controling parts for preventive maintenance to be effective and efficient. The system was then developed as a web-based system by using the programming language PHP (Hypertext Preprocessor). Several system functions were developed in accordance with the targeted users, each with different access rights. There are four main subsystems, namely, machinery checking subsystem, stock management subsystem, subsystems purchase of components, and supervision subsystems
Keyword: management information systems, PT SHS, parts control, Preventive maintenance

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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