Judul: Improving the Appearance of Abiu Fruit (Pouteria caimito Radlk.) through Different Types and Application Periods of Pesticides
Abstrak: Abiu merupakan tanaman hasil introduksi dari Amazon yang potensial dikembangkan di Indonesia. Buah abiu memiliki cita rasa yang tinggi dan kaya akan manfaat. Salah satu permasalahan yang umum ditemukan pada buah abiu yakni tingkat kemulusan buah yang rendah. Penelitian ini bertujuan mengetahui pengaruh bahan aktif dan periode aplikasi pestisida terhadap tingkat kemulusan buah abiu. Penelitian dilakukan di Kampung Babakan Lebak, Kelurahan Balumbang Jaya, Kecamatan Bogor Barat dan Laboratorium Pascapanen Departemen Agronomi dan Hortikultura, Institut Pertanian Bogor. Rancangan percobaan yang digunakan adalah rancangan petak terbagi (split-plot) RKLT dengan 5 ulangan. Faktor petak utama yaitu periode aplikasi, yaitu: 1, 2, 3 MSA (V1); 1, 3, 6 MSA (V2); dan 1, 4, 7 MSA (V3). Faktor anak petak yaitu bahan aktif pestisida, yaitu: mankozeb 80WP dan streptomisin sulfat 20WP (P1); propineb 70WP (P2); profenofos 500EC (P3); dan kontrol (P4). Perlakuan kombinasi bahan aktif mankozeb dengan streptomisin sulfat memberikan pengaruh yang nyata terhadap variabel kemulusan buah abiu. Aplikasi pestisida pada periode berbeda tidak memberikan pengaruh yang nyata terhadap kemulusan buah abiu. Perlakuan terbaik yaitu pemberian bahan aktif mankozeb dan streptomisin sulfat dengan kemulusan buah abiu sebesar 77,31%., Abiu is an introduced plant species from the Amazon that has the potential to be developed in Indonesia. Abiu has a good taste and rich in benefits for health. Fruit defects are the main problem that decreases the appearance quality of abiu. This research aimed to determine the effect of pesticide active compounds used with application periods on the appearance of abiu. The research was conducted at Kelurahan Balumbang Jaya, Bogor Barat, and the Post-Harvest Laboratory of the Department of Agronomy and Horticulture, IPB University Bogor. The experimental design used was a split-plot, randomized complete block design with five replications. The main plot is the application periods, namely 1, 2, 3 MSA (V1); 1, 3, 6 MSA (V2); and 1, 4, 7 MSA (V3). The sub-plot is the pesticide active compounds, namely 80WP mankozeb and 20WP streptomycin sulfate (P1); propineb 70WP (P2); profenofos 500EC (P3), and control (P4). The active compounds mankozeb and streptomycin sulfate had a significant effect on fruit smoothness. The application of pesticides at different periods did not have a significant effect on the smoothness of the abiu fruit. The best treatment was the mankozeb and streptomycin sulfate pesticide, which produced 77,31% smoothness of the abiu fruit.
Keyword: Abiu, fruit quality, fruit smoothness, active compounds, application period

Judul: Optimizing Active Compund of Pesticides and Spraying Intervals to Increase the Quality of Abiu Fruit (Pouteria caimito Radlk.).
Abstrak: Abiu merupakan buah tropika yang berasal dari Amazon. Abiu berpotensi untuk dikembangkan di Indonesia karena kaya nutrisi dan manfaat. Kecacatan kulit buah abiu menjadi masalah yang umum dijumpai. Penelitian ini bertujuan mempelajari pengaruh pengaplikasian beberapa jenis bahan aktif pestisida dan interval penyemprotan serta interaksiknya terhadap kualitas buah abiu. Penelitian dilakukan di kebun buah abiu dan Laboratorium Pascapanen Departemen Agronomi dan Hortikultura, Fakultas Pertanian IPB. Rancangan yang digunakan adalah rancangan kelompok lengkap teracak dua faktor dengan tiga ulangan. Faktor pertama adalah jenis bahan aktif pestisida, yaitu mankozeb+streptomisin sulfat (P1), benomil (P2), dimetoat (P3), klorpirifos (P4), dan kontrol (P5). Faktor kedua adalah interval penyemprotan, yaitu 1x2 minggu (V1), 1x1 minggu (V2), dan 2x1 minggu (V3). Perlakuan jenis bahan aktif pestisida berpengaruh nyata terhadap kemulusan buah abiu. Bahan aktif benomil tidak memberikan pengaruh berbeda nyata dengan bahan aktif dimetoat dan klorpirifos. Benomil mempertahankan kemulusan sebesar 73,88%, dimetoat 71,33%, dan klorpirifos 65,77%. Interval penyemprotan dan interaksi keduanya tidak berbeda nyata terhadap kemulusan buah. Kedua perlakuan tidak berpengaruh nyata terhadap perkembangan buah, kelunakan, bobot, volume, PTT, TAT, dan vitamin C., Abiu is a tropical fruit from Amazon. It has potential to be developed in Indonesia. Imperfections that found in abiu’s skin are commonly problem. This study aims to determine the effect of several active compund pesticides, spraying intervals, and their interaction on the quality of abiu fruit. The research was conducted at abiu field and The Postharvest Laboratory of Agronomy and Horticulture Department, Faculty of Agriculture IPB. The experimental design used was a factorial completely randomized block design with three replications. The first factor is the active compound of pesticides, namely mancozeb+streptomycin sulfate (P1), benomyl (P2), dimethoate (P3), chlorpyrifos (P4), and control (P5). The second factor is spraying intervals, namely 1x2 week (V1), 1x1 week (V2), and 2x1 weeks (V3). The active compound of pesticides did significantly affect the fruit smoothness. Benomyl didn’t give significantly affect than dimethoat and chlorpyrifos. Benomyl gave 73,88% in maintaining the smoothness abiu fruit, dimethoat at 71,33%, and chlorpyrifos at 65,77%. The spraying interval and its interaction with the active coumpund treatments didn’t significantly affect the fruit smoothness.Both treatments had no significant effect on fruit development, firmness, weight, volume, TSS, TAT, and vitamin C variables.
Keyword: Abiu, Active compound of pesticides, Fruit quality, Spraying intervals

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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