Judul: Effect of Mulch Application on Temperature and Groundwater Fluctuations and Red Chili Plant Growth (Capsicum annum L.) on Latosol Dramaga
Abstrak: Cabai merah merupakan bahan pangan penting. Namun upaya pemenuhan bahan pangan ini dihadapkan berbagai tantangan, salah satunya adalah lahan yang terbatas. Pemanfaatan lahan yang terbatas secara optimal sehingga dapat menghasilkan produktivitas yang tinggi antara lain dengan menerapkan teknik budidaya yang sesuai salah satunya yaitu dengan pengaplikasian mulsa plastik. Penelitian dilakukan di daerah dengan curah hujan tahunan yang tinggi seperti di Dramaga, Bogor. Penelitian ini bertujuan mengetahui pengaruh mulsa plastik terhadap karakteristik tanah khususnya terhadap fluktuasi suhu dan kadar air tanah harian serta lebih lanjut pengaruhnya terhadap pertumbuhan dan produktivitas tanaman cabai merah pada Latosol Dramaga. Penelitian ini menggunakan rancangan acak kelompok (RAK) faktor tunggal dengan perlakuan tanpa mulsa (M0) dan mulsa plastik (M1). Data yang diperoleh dianalisis ragam pada tingkat kepercayaan 95% atau taraf nyata 5%. Hasil penelitian menunjukkan suhu dan kadar air tanah harian cenderung lebih tinggi pada perlakuan mulsa plastik. Perlakuan mulsa plastik berpengaruh nyata terhadap suhu dan kadar air tanah. Perbedaan nyata terdapat pada tinggi tanaman pada umur 8 MST dan jumlah daun pada umur 2 MST dan 8 MST. Perlakuan mulsa plastik berpengaruh nyata terhadap bobot buah., Red chili is an important food ingredient. However, efforts to fulfill this food supply are faced with various challenges, one of which is limited land. Utilization of limited land optimally so that it can produce high productivity, among others, by applying appropriate cultivation techniques, one of which is the application of plastic mulch. The study was conducted in areas with high annual rainfall such as in Dramaga, Bogor. This study aims to determine the effect of plastic mulch on soil characteristics, especially on dailiy fluctuations in temperature and daily groundwater content and further effect on the growth and productivity of red chili plants in Latosol Dramaga. This study used a single factor randomized block design (RAK) with non-mulch treatment (M0) and plastic mulch (M1). The data obtained was analyzed at a confidence level of 95% or a real level of 5%. The results showed daily groundwater content tended to be higher on plastic mulch treatment. The treatment of plastic mulch has a real effect on the temperature and content of groundwater. The real difference is in the height of the plant at the age of 8 MST, and the number of leaves at the age of 2 MST and 8 MST. The treatment of plastic mulch has a real effect on the weight of the fruit.
Keyword: rainfall, moisture content, plastic mulch, production, soil temperature

Judul: Simulasi pertumbuhan untuk menganalisis pengaruh jadwal  tanam terhadap produktivitas budidaya Cabai Merah (Capsicum  annuum L.) di Kabupaten Nganjuk
Abstrak: Tanaman cabai merah (Capsicum annuum L.) merupakan tanaman yang memiliki nilai ekonomis yang tinggi, namun jumlah produksi cabai merah yang fluktuatif di tingkat pasar, dapat mengakibatkan jumlah ketersediaan cabai merah yang tidak mencukupi. Sebagai solusi dibutuhkannya pendugaan jumlah hasil panen cabai merah di sepanjang tahun. Penelitian ini dilakukan untuk membuat simulasi model tanaman cabai merah yang dapat mensimulasikan proses pertumbuhan dan perkembangan tanaman cabai merah. Simulasi model tanaman cabai merah ini menggunakan parameter cuaca harian, yang meliputi: suhu maksimum, suhu minimum, suhu rata-rata, kelembaban, kecepatan angin, curah hujan, radiasi matahari, dan evaporasi potensial. Keluaran dari simulasi model ini adalah komponen biomassa harian berupa organ buah panen cabai merah (kg/ha). Ketelitian pada Kecamatan Gondang sebesar 65.3 %, Kecamatan Pace sebesar 83.1 %, dan ketelitian terhadap data rata-rata panen sebesar 93.2%., Red chilies (Capsicum annuum L.) are plants with a high economic value, but the red chilies production in market is fluctuative, so it makes the availability of red chilies is inadequate. As a solution, an estimation of the number of red chiles production in a year is necessary. This research was conducted to make a red chilies model simulation that could simulate the growth and development processes of red chilies. This red chilies model simulation used daily weather parameters including: maximum temperature, minimum temperature, average temperature, humidity, wind speed, rainfall, sun radiation, and potential evaporation. The outputs of this model simulation were daily biomass components such as red chilies crops organ (kg/ha). Precision value in Gondang Sub-district was 65.3%, precision value in Pace Sub-district was 83.1%, and precision value of average red chilies production was 93.2%.
Keyword: biomassa, cabai merah, cuaca harian, simulasi model

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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