AbstrakPengujian unjuk kerja pompa sentrifugal multistage berkapasitas 118,5 kW di kawasan Pembangkit Listrik Tenaga Panas Bumi (PLTP) daerah Jawa Barat saat ini akan menyesuaikan prosedur standar. Standar pengujian pompa diterapkan pada proses pengujian pompa dengan tujuan nilai hasil pengujian valid. Nilai head dan debit yang didapat dari pengujian dibandingkan dengan hasil pengujian sebelum penerapan standar. Pengujian pompa sentrifugal menerapkan metode pengujian lapangan dengan menerapkan standar ISO 9906-2012. Standar ISO 9906-2012 adalah panduan baku pengujian pompa rotodinamik. Dari hasil pengujian, didapatkan kurva pompa sentrifugal multistage debit maksimal 116,64 m3/h pada head 275,13 m. Pada data spesifikasi kapasitas pompa sebesar 108 m3/jam dan head total sebesar 300 m. Hal ini berarti prosedur pengujian pompa ISO 9906-2012 dapat memungkinkan kita untuk melihat kinerja pompa aktual.Kata kunci: pompa sentrifugal, pengujian lapangan, uji kinerja pompa, ISO 9906  AbstractPerformance test of multistage centrifugal pump at geothermal power plant area around west java is about to adapt standard procedure. Pump testing standards are applied during pump performance test in order to valid test result values. Head and flowrate value from current test compared with previous test result before standard are applied. Pump performance test use field test method by applying ISO 9906-2012 standard. ISO 9906-2012 standard is a normative guidance for rotodynamic pump testing. The test result shows multistage centrifugal pump curve maximum flowrate is 116,64 m3/h at total head 275,13 m. Pump specification sheet shows that maximum capacity is 108 m3/h and total head 300 m. It indicates that ISO 9906-2012 standard pump testing procedure allow us to determine actual pump performance.Kata kunci: Centrifugal pump, field test, performance test, ISO 9906

This research deals with a multi-job Integer batch scheduling problem on a single machine with different due dates. Every job demanded one or more parts, and the single machine processed the job into a number of batches. The objective is to minimize total actual flow time, defined as the total flow time of all jobs starting from the arrival to the common due date. The decisions are to determine the sequence of jobs, the number of batches, batch size, and sequence of all batches on a single machine. This research proposes three algorithms, developed based on the longest due date rule (The P1-LDD Algorithm), the adjacent pairwise interchange method (The P2-API Algorithm), and the permutation method (The P3-PM Algorithm). The numerical experience shows that the three algorithms produce an outstanding solution. The P1-LDD Algorithm fits to solve a simple problem. The P2-API Algorithm has superior to solve a big complicated problem. The P3-PM Algorithm has the best performance to solve small complicated problems.

Model drum dryer digunakan untuk mengeringkan berbagai biji-bijian atau produk pertanian. Salah satu kegunaannya adalah untuk mengeringkan gabah. Pemilihan desain silinder tipe horizontal yang digunakan dalam pengeringan ini akan mempengaruhi distribusi udara yang memasuki ruang pengering. Penelitian ini bertujuan untuk mengetahui distribusi kecepatan udara dan distribusi suhu dalam ruang pengering tipe silinder horizontal. Sehingga hasil simulasi akan mengetahui yang optimal bahwa proses pengeringan tersebut merata. Metode yang digunakan dalam penelitian ini adalah percobaan virtual dengan menggunakan software Computational Fluid Dynamics (CFD) sehingga hasil simulasi dapat memberikan gambaran distribusi kecepatan aliran udara pada drum dryer untuk memudahkan penentuannya desain ruang pengering. Sedangkan variasi kecepatan aliran udara menggunakan "4,5" m/s, "6,75" m/s, dan "9" m/s dan suhu "38,14" °C, "39,60" °C, "40,17" °C dan "41,55" °C. Dari variasi tersebut hasil simulasi CFD yang paling optimal didapat pada variasi kecepatan aliran udara sebesar 9 m/s dan temperatur 41,55 °C dengan nilai perpindahan kalor yang diperoleh di dalam chamber dan pengeringan dinding, masing-masing sebesar 3.931 W dan 31.354 W.

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In this study, a simulation of a vapor compression heat pump system for bed drying of rough rice have been carried out for various thicknesses in the range of 20-50 cm and various drying air mass flow rates in the range of 0.06 - 0.22 kg/s-m2. The modelling used was grouped into two parts, i.e. the determination of temperature and humidity of the air coming out of the heat pump and the drying process of the rough rice using these air conditions. Parameters related to flow rate and energy were expressed in units of cross-sectional area of the drying bed. Simulation results showed significant differences in drying time and temperature for various thicknesses and air mass flow rates but their energy consumptions were similar. Under these conditions the drying temperature and drying time obtained ranged between 34-45°C and 8-15 hours, respectively while the specific energy consumption was relatively low i.e. in the range of 1.07-1.36 MJ/kg of evaporated water for all the scenarios tested. The specific drying air mass flow rate of 0.3 and 0.5 kg/s/m3 did not provide significant differences in specific energy consumption. For the field applications, the selection of conditions for thickness and the appropriate air mass flow rate will depend on the user preference including the ease of mixing, drying time or energy consumption.