Judul: Growth Responses of 5 Rambutan Varieties (Nephelium lappaceum L.) to Addition of Artificial Light LED (Light Emitting Diode)
Abstrak: Rambutan (Nephelium lappaceum L.) merupakan buah yang cocok ditanam di daerah tropis dan Indonesia menjadi negara dengan plasma nutfah terbesar di dunia. Menjaga kekayaan hayati ini perlu adanya teknik baru untuk memperbanyak dan mengoptimalkan pertumbuhan tanaman rambutan. Penelitian ini menggunakan rancangan petak tersarang (nested) dua faktor yaitu cahaya LED (Light Emitting Diode) dan varietas. Cahaya LED yang digunanakan yaitu merah, biru, dan putih sedangkan varietas yang diteliti Sikoneng, Parakan, Cilebak, Kerikil, dan Garuda. Tanaman rambutan yang diberi tambahan LED biru memiliki kandungan klorofil dan gula daun yang lebih tinggi sedangkan LED merah dapat menpengaruhi pertumbuhan morfologi seperti tinggi tanaman, diameter batang, dan ukuran daun. LED merah berperan dalam proses pemanjangan dan penguatan sel sehingga daun menjadi lebih tebal. Penambahan LED putih dapat memunculkan banyak senyawa metabolit pada dua varietas yaitu Garuda dan Parakan tetapi, penambahan LED putih 1- 4 µmol m-2 s-1 dapat menyebabkan stres pada tanaman sehingga tanaman mengalami kematian dan rontok daun. Varietas Garuda lebih tahan dan lebih baik pertumbuhanya dibandingkan dengan varietas lain., Rambutan (Nephelium lappaceum L.) is a fruit that planted in tropical areas and Indonesia is the country with the largest germplasm in the world. Maintaining this biological wealth requires new techniques to reproduce and optimize the growth of rambutan plants. This study used a two-factor nested design, namely LED (Light Emitting Diode) and varieties. The LED light source were red, blue, and white, while the varieties studied included Sikoneng, Parakan, Cilebak, Kerikil, and Garuda. Rambutan plants that are given additional blue LEDs have higher chlorophyll and leaf sugar content while red LEDs can affect morphological growth such as plant height, stem diameter, and leaf size. Red LED plays a role in the process of elongation and strengthening of cells so that the leaves become thicker. The addition of white LEDs can generate many metabolite compounds on two varieties, namely Garuda and Parakan, but the addition of 1- 4 µmol m-2 s-1 white LEDs can cause stress on plants so that plants experience death and leaf loss. Garuda variety is more resistant and grows better than other varieties
Keyword: chlorophyll, glucose, LEDs, Nephelium lappaceum L., secondary metabolite, Varieties

Judul: Kecapi Seedlings (Sandoricum koetjape Merr.) Growth Response Under Different Spectrum and Intensities of Light Emitting Diode
Abstrak: Kecapi (Sandoricum koetjape Merr.) merupakan buah lokal dari famili Meliaceae yang sudah jarang dibudidayakan. Harga pasar buah ini tidak stabil akibat produksi dan kualitas tidak konsisten. Untuk memperbaiki sistem budidaya tanaman buah ini dapat dilakukan dengan modifikasi lingkungan yaitu penggunaan LED (Light Emitting Diode) sebagai cahaya buatan. Penelitian ini bertujuan mengetahui perubahan respons morfologi, fisiologi, dan anatomi terhadap perbedaan spektrum dan tingkat intensitas cahaya LED. Penelitian dilaksanakanberdasarkan Rancangan Acak Lengkap (RAL) dua faktor terdiri dari spektrum LED (ungu dan putih) dan intensitas cahaya (dua dan empat lampu). Hasil penelitian menunjukkan respons morfologi dan fisiologi terbaik pada perlakuan LED putih intensitas tinggi (WH). LED putih intensitas rendah (WL) meningkatkan kandungan klorofil daun dan laju fotosintesis. Respons anatomi terbaik pada perlakuan LED ungu intensitas rendah (PL). Peningkatan lebar daun pada LED ungu intensitas tinggi (PH). Kandungan glukosa menurun pada semua perlakuan dan peningkatan kandungan fruktosa hanya terjadi pada perlakuan LED ungu dengan intensitas rendah., Kecapi (Sandoricum koetjape Merr.) is a local fruit from the Meliaceae family that is rarely cultivated. The market price of this fruit is unstable due to inconsistent production and quality. Improving the cultivation system of this fruit plant can be done by modifying the environment, the use of LED (Light Emitting Diode) as artificial light. This study aims to determine changes in morphological, physiological, and anatomical responses to different spectra and intensity levels of the LED light. The research was conducted based on a two-factor completely randomized design (CRD) consisting of LED spectrum (purple and white) and light intensity (two and four lights). The results showed the best morphological and physiological responses in the treatment of high-intensity white LED (WH). Low-intensity white LED (WL) increased leaf chlorophyll content and photosynthesis rate. The best anatomical response was in the low-intensity purple LED (PL) treatment. Increased leaf width in high-intensity purple LED (PH). Leaf glucose content decreased in all treatments and an increase in fructose content only occurred in the low-intensity purple LED treatment.
Keyword: chlorophyll, glucose, intracellular CO2, photosynthesis, stomata

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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