Judul: Perancangan sistem pakar fuzzy untuk penentuan efektivitas kultivasi cendawan mikoriza arbuskula sebagai pupuk hayati, Design of Fuzzy Expert System for Determination of Cultivation Effectiveness of Arbuscular Mycorrhizal Fungi as Biofertilizer
Abstrak: The use of biofertilizer provides many benefit, including the increased of agricultural production, quality improvement of agricultural product, and reducing the use of artificial fertilizer as well. One of such biofertilizer is Arbuscular Mycorrhizal Fungi (AMF). In cultivation of AMF there are some environment factors which influence cultivation effectiveness, such as soil pH, mean temperature, soil water content, and suitability of host plant. Incompatible factor can give negative impact on AMF cultivation. This research designed an expert system to observe effectiveness value of AMF cultivation based on certain environment factor. This research focused on three AMF specieses, Entrophospora columbiana, Glomus fasciculatum, and Glomus manihotis. This system was built using Fuzzy Inference System (FIS) with four fuzzy parameters: suitability of host plant, soil pH, mean temperature and soil water content. Rules as knowledge base had been built with total 144 rules for each AMF species. Mamdani method is used as inference process. System gives cultivation effectiveness value as output. The effectiveness value shows how effective cultivation process on certain input condition as compared to its best condition. The effectiveness value also divides into four category: not effective, slightly effective, moderately effective, and effective. Based on data verification, system is still unable to gives an accurate effectiveness percentage, altough it is quite good on giving right effectiveness category. To be used in real condition, this system must still be developed further. For example by adding other factors as parameters, such as cultivation time or type of cultivation media.
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Judul: Efektivitas Fungi Mikoriza Arbuskula (FMA) dalam Memperbaiki Produktivitas Rumput Gajah (Pennisetum purpureum Schum.) Berdasarkan Periode Pemanenan
Abstrak: The use of arbuscular mycorrhizal fungi (AMF) was expected to be an alternative environmentally friendly technology and efficiency of fertilizer to increase the productivity of forage. This study was aimed to determine the level of production of elephant grass (Pennisetum purpureum Schum.) inoculated by AMF and fertilizer dose reduction based on different harvesting period. This research used Completely Randomized Factorial Design with 2 treatments and 3 replications. The first treatment was fertilizer: P0 (control), P1 (100% fertilizer dose), and P2 (50% fertilizer dose and inoculated by AMF). The second factor was the interval of harvest H30 (30th day of harvest), H50 (50th day of harvest, and H60 (60th day of harvest). Variables measured were plant height increment of each week, the production of dry weight on the first harvesting period, the production of dry weight on second harvesting period, and percent of infection AMF. It can be concluded that the P2H60 treatment with 10 grams of AMF inoculation and fertilizer dose 50% (SP36 75 kg/ha, KCl 75 kg/ha, manure 2 ton/ha, and urea 100 kg/ha) on 60th day of harvest elephant grass get the best production, either the first and second periods and more effective and efficient use of fertilizer.
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Judul: Gelombang Soliter Internal pada Laut Dalam untuk Aliran yang Tunak
Abstrak: Gelombang internal adalah suatu gelombang yang terjadi di bawah permukaan air laut. Gelombang ini muncul karena adanya perbedaan rapat massa di setiap lapisan air laut. Salah satu gelombang internal yang memiliki sifat mempertahankan bentuk dan kecepatannya adalah gelombang soliter internal. Penelitian ini mengkaji gerak gelombang soliter internal pada laut dalam. Penurunan persamaan gerak gelombang internal pada laut dalam menggunakan asumsi bahwa aliran fluida berbentuk tunak. Dalam hal ini persamaan dasar fluida dinyatakan dalam formulasi Lagrange dengan ketinggian fluida dari posisi kesetimbangannya yang merupakan peubah Lagrangenya. Metode yang digunakan untuk menurunkan persamaan gerak gelombang internal adalah metode asimtotik. Dalam metode ini, simpangan gelombang internal dinyatakan dalam uraian asimtotik. Selanjutnya dengan menyeimbangkan faktor taklinear dan dispersi, maka diperoleh persamaan gerak gelombang berupa persamaan Benjamin-Ono (BO). Rumusan gelombang soliter internal dari persamaan BO digunakan untuk mengkaji gerak gelombang soliter pada fluida dua lapisan untuk laut dalam. Hasil yang diperoleh adalah profil gelombang soliter pada setiap kedalaman. Gelombang soliter internal yang memiliki amplitudo terbesar dicapai pada batas antara kedua lapisan fluida, sedangkan di permukaan gelombang relatif kecil.
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