Judul: Effect of Composition of Compost, Fly ash, and  Mineral Fertilizer on N Availability of Pineapple (Ananas comosus L. Merr)  Growth
Abstrak: Nitrogen merupakan unsur hara esensial bagi pertumbuhan tanaman. Kehilangan nitrogen dalam tanah disebabkan oleh adanya pencucian, penguapan, dan yang terserap oleh tanaman. Penelitian ini bertujuan mengidentifikasi pengaruh persentase kompos dan fly ash terhadap ketersediaan hara N pada pertumbuhan tanaman nanas, serta mengidentifikasi perbaikan pertumbuhan tanaman nanas dan sistem perakarannya akibat aplikasi SRF dibandingkan dengan pupuk standar baku PT. GGP. Penelitian dilaksanakan di Kebun Reasearch and Development PT Great Giant Pineapple, Kabupaten Lampung Tengah pada bulan Oktober 2021 – Januari 2022. Tanaman yang diamati merupakan tanaman nanas klon GP3. Penelitian ini menggunakan 3 komposisi kompos dan fly ash dalam pupuk mineral yaitu tanpa pemberian kompos dan fly ash, 40% kompos dan 20% fly ash, serta 20% kompos dan 40% fly ash masing-masing 4 ulangan. Hasil penelitian menunjukkan persentase kompos dan fly ash tidak berbeda nyata terhadap ketersediaan N dalam tanah, N tercuci, dan N menguap, serta pertumbuhan daun dan akar., Nitrogen is an essential nutrient for plant growth. Loss of nitrogen in the soil is caused by leaching, evaporation, and being absorbed by plants. This study aims to identify the effect of the percentage of compost and fly ash on the availability of N-nutrients on the growth of pineapple plants, as well as identify the improvement of pineapple plant growth and root system due to SRF application compared to standard standard fertilizers of PT. GGP. The research was carried out at the Research and Development Garden of PT Great Giant Pineapple, Central Lampung Regency in October 2021 – January 2022. The plant to be monitored is a GP3 clone of pineapple. This study uses 3 compositions of compost and fly ash in mineral fertilizers, namely without compost and fly ash, 40% compost and 20% fly ash, as well as 20% compost and 40% fly ash with 4 replications each. The results showed that the percentages of compost and fly ash were not significantly different to the availability of N in the soil, leached N, evaporated N, and root and leaf growth.
Keyword: plant vegetative, slow release fertilizers, waste coal

Judul: Effect od Slow Release Fertilizer on Nitrogen Availability in Soil and Growth Pineaplle (Ananas comosus L. Merr)
Abstrak: Slow Release Fertilizer (SRF) merupakan salah satu modifikasi pupuk yang bertujuan untuk meningkatkan efisiensi unsur-unsur yang terdapat di dalam pupuk dengan mengatur pelepasannya secara lambat atau bertahap. Kegiatan penelitian dilaksanakan pada bulan September 2021-Maret 2022 di Kabupaten Lampung Tengah, PT Great Giant Food. Kegiatan penelitian bertujuan mengetahui pengaruh pupuk slow release fertilizer terhadap tingkat ketersediaan N dan pertumbuhan tanaman nanas(Ananas comosusL. Merr. ) secara kontinu. Metode yang dilaksanakan selama penelitian, yaitu membuat pupuk slow release fertilizer dengan mencampurkan seluruh unsur mineral (Urea, ZA, K2SO4, KCl, DAP, MgSO4, Kiest G, FeSO4, ZnSO4, Borax, Bifent G) sebagai pupuk standar, kemudian akan dicampurkan dengan masing-masing 3 jenis formulasi pupuk dengan kandungan fly ash dan kompos yang berbeda dan menyelimuti pupuk tersebut dengan bahan polimer sehingga pelepasan pupuk didalam tanah menjadi lambat. Hasil pengamatan ketersediaan N dalam tanah menunjukan perlakuan pupuk belum menyediakan kecukupan hara N dalam tanah untuk kurun waktu 5 bulan. Konsentrasi NO3- dan NH4+ tercuci dipengaruhi oleh lahan yang gundul dan curah hujan. Penguapan NH3 diakibatkan oleh proses evaporasi dan suhu tinggi. Perlakuan pupuk pada pertanaman nanas memberikan dampak positif terhadap sistem pertumbuhan vegetatif tanaman., Slow Release Fertilizer (SRF) is a fertilizer modification that aims to increase the efficiency of the elements contained in fertilizers by regulating their release slowly or gradually. The research activity was carried out in September 2021-March 2022 in Central Lampung Regency, PT Great Giant Food. The aim of the research was to determine the effect of slow release fertilizer on the level of N availability and continuous growth of pineapple ( Ananas comosus L. Merr ) plants. The method carried out during the research was making slow release fertilizer by mixing all elements mineral (ZA, K2SO4, KCl, DAP, MgSO4, Kiest G, FeSO4, ZnSO4, Borax, Bifent G) asa standard fertilizer, then mixed with each other the 3 types of fertilizer formulations with different fly ash and compost contentand covering the fertilizer with polymer material so tthat the release of fertilizer in the soil is slow. The result of observations of the availability of N in the soil showed that the fertilizer treatment had no provided sufficient N nutrients in the soil for a peroid of 5 months. The concentration of leachhed NO3- and NH4+ is affected by demudedland and rainfall. Evaporation of NH3 is coused by the evaporation process and high temperature. Fertilizer treatment on pineapple plantation has a positive impact on the plants vegetative growth system.
Keyword: Evaporation, Vegetative Growth, SRF

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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