Judul: Study of the Diversity Characteristics of Abiu (Pouteria caimito Radk.) in Balumbang Jaya Village, Bogor City
Abstrak: Abiu (Pouteria caimito Radk.) merupakan tanaman eksotis yang berasal dari daerah Amazon Tropis. Sampai saat ini informasi karakter morfologi dan kualitas buah abiu masih sangat terbatas. Penelitian ini bertujuan mengidentifikasi dan melengkapi data karakter tanaman abiu (Pouteria caimito Radk.) yang ditanam di Kebun Balumbang Jaya, Kecamatan Bogor Barat, Kota Bogor, Jawa Barat (6⁰ 30” − 6⁰ 45” LS, dan 106⁰ 30” − 106⁰ 45” BT). Pengamatan morfologi bunga abiu di Laboratorium Mikroteknik dan pengujian kualitas buah di Laboratorium Pascapanen, Departemen Agronomi dan Hortikultura, Fakultas Pertanian IPB University. Pengamatan dan analisis dilaksanakan pada bulan Februari hingga Juli 2023. Prosedur yang digunakan dalam pengambilan sampel yaitu metode random sampling dengan analisis data menggunakan analisis deskriptif berdasarkan modus data dan data kuantitatif yang diolah dengan bantuan perangkat lunak Microsoft Office Excel 365. Hasil penelitian menunjukkan bahwa jumlah daun dan luas daun total memiliki keragaman yang tinggi pada karakter kuantitatif vegetatif. Keragaman yang tinggi pada karakter generatif bunga terdapat pada panjang stamen bunga abiu. Terdapat keragaman bentuk buah abiu di Kelurahan Balumbang Jaya yang terdiri dari oblate (41.67%), spheroid (16.67%), dan ellipsoid (41.67%) dengan keragaman bentuk ujung buah abiu yaitu rounded (8,3%), flattened (50%), dan pointed (41,67%)., Abiu (Pouteria caimito Radk.) is an exotic plant from the Tropical Amazon region. Until now, information on the morphological characteristics and quality of abiu fruit is still very limited. This study aims to identify and complete the data and the characteristics of the abiu plant which grown in Balumbang Jaya Gardens, West Bogor District, Bogor City, West Java (6⁰ 30” − 6⁰ 45” S, and 106⁰ 30” − 106⁰ 45” E). The observation of abiu flower morphology was carried out at the Microtechnic Laboratory and fruit quality testing at the Postharvest Laboratory, Department of Agronomy and Horticulture, Faculty of Agriculture IPB University. The study and analysis was done from February to July 2023. The procedure used in sampling is the random sampling method with data analysis using descriptive analysis based on data mode and quantitative data processed with the help of Microsoft Office Excel 365 software. The results showed that the leaf numbers and total leaf area had a high variation in quantitative vegetative character. The high diversity of flower generative characteristics is found in the stamen length of the abiu flower. There is a diversity of abiu fruit shapes in Balumbang Jaya Village consisting of oblate (41.67%), spheroid (16.67%), and ellipsoid (41.67%) with a variety of abiu fruit tip shapes, namely rounded (8,3%), flattened (50%), dan pointed (41,67%).
Keyword: ellipsoid, generatif, oblate, spheroid, vegetatif, ellipsoid, generative, oblate , spheoroid, vegetative

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: 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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