Judul: Growth Parameters, Proximate, and Reducing Sugar Content of Cilembu Sweet Potato (Ipomoea batatas L) with Maggot (Black Soldier Fly) Fertilization.
Abstrak: Tingkat kemanisan ubi cilembu dipengaruhi oleh beberapa faktor salah satunya pemupukan. Pemberian pupuk kasgot dapat mempengaruhi pertumbuhan ubi cilembu sehingga diharapkan diperoleh ubi cilembu manis jika ditanam di luar daerah cilembu. Namun, belum diketahui pengaruh pemberian pupuk kasgot terhadap tingkat kemanisannya yang ditandai oleh kadar gula pereduksi. Penelitian ini bertujuan untuk mengukur parameter proksimat yang terdiri atas kadar air, kadar abu, kadar lemak, kadar protein, kadar karbohidrat, dan kadar serat kasar serta mengukur kadar gula pereduksi ubi cilembu yang diberi pupuk kasgot. Pembuatan simplisia menggunakan metode oven, kemudian diuji proksimat dengan metode gravimetri untuk kadar air, abu dan serat kasar, metode Kjeldahl untuk kadar protein, metode soxhlet untuk kadar lemak. Hasil yang diperoleh menunjukkan parameter proksimat selain karbohidrat dan serat, serta gula pereduksi ubi cilembu meningkat setelah pemberian pupuk kasgot. Simpulan dari penelitian ini adalah pemupukan kasgot meningkatkan kandungan proksimat dan kadar gula pereduksi pada tanaman ubi cilembu dengan konsentrasi pemupukan yang sesuai., The level of sweetness of cilembu sweet potatoes is influenced by several factors, one of which is fertilization. The application of kasgot fertilizer can affect the growth of cilembu sweet potatoes so that it is expected to obtain sweet cilembu sweet potatoes if planted outside the cilembu area. However, the effect of kasgot fertilizer on the level of sweetness, which is characterized by reducing sugar content, is not yet known. This study aim to measure proximate parameters consisting of water content, ash content, fat content, protein content, carbohydrate content, and crude fiber content and measure the reducing sugar content of cilembu sweet potato treated with kasgot fertilizer. Making simplisia using the oven method, then tested proximate by gravimetric method for water content, ash and crude fiber, Kjeldahl method for protein content, soxhlet method for fat content. The results obtained showed that proximate parameters other than carbohydrates and fiber, and reducing sugars of cilembu sweet potatoes increased after applying kasgot fertilizer. The conclusion of this study show that kasgot fertilization increases proximate content and reducing sugar content in cilembu sweet potato plants with the appropriate fertilization concentration.
Keyword: cilembu sweet potato, kasgot fertilizer, proximate analysis, reducing sugar

Judul: Application of Edible Coating from Corn Starch and Red Galangal to Maintain The Quality of The Cilembu Sweet Potatoes
Abstrak: Komoditas ubi jalar cilembu banyak diminati oleh konsumen domestik maupun mancanegara karena mengandung karbohidrat dan kalori yang cukup tinggi, serta rasa manis seperti madu yang menjadi ciri ubi jalar cilembu. Namun, karena umur simpan singkat dan kualitas hasil panen yang rendah, ubi jalar cilembu memerlukan penanganan pascapanen yang tepat. Edible coating merupakan cara efektif mempertahankan kualitas ubi jalar cilembu, karena berfungsi sebagai pelindung produk yang aman dikonsumsi dan dapat memperlambat transpirasi serta respirasi ubi jalar cilembu. Tujuan penelitian ini yaitu mengatahui pengaruh penggunaan edible coating dengan kombinasi pati jagung dan ekstrak lengkuas merah terhadap kualitas ubi jalar cilembu selama masa simpan. Prosedur penelitian meliputi persiapan sampel, pembuatan larutan edible coating, pengaplikasian edible coating, dan pengamatan selama 30 hari masa simpan. Larutan edible coating terbuat dari kombinasi pati jagung 2% serta lengkuas merah 1%, 3%, dan 5%. Pengaplikasian edible coating dilakukan menggunakan metode pencelupan sebanyak satu kali selama satu menit. Edible coating P1L3 merupakan perlakuan paling efektif untuk menjaga kualitas mutu dan memperpanjang masa simpan ubi jalar cilembu dengan meminimalisir susut bobot 8.91%, kadar air 66.02%, kekerasan 7.49 kgf, total padatan terlarut 17.3oBrix, dan spot coklat 12.33%., The cilembu sweet potatoes commodity is in great demand by domestic and foreign consumers because it contains fairly high carbohydrates and calories, as well as a sweet taste like honey which is a characteristic of cilembu sweet potatoes. However, due to the short shelf life and low yield quality, cilembu sweet potatoes require proper postharvest handling. Edible coating is an effective way to maintain the quality of cilembu sweet potatoes, because it functions as a protector of products that are safe for consumption and can slow down the transpiration and respiration of cilembu sweet potatoes.The purpose of this study is to determine the effect of edible coating with a combination of corn starch and red galangal extract on the quality of cilembu sweet potatoes during the shelf life. The research procedure includes sample preparation, making edible coating solution, applying edible coating, and observation for 30 days of shelf life. Edible coating solution is made from a combination of 2% corn starch and 1%, 3%, and 5% red galangal. The application of edible coating is carried out using the dipping methode once for one minute. Edible coating P1L3 is the most effective treatment to maintain quality and extend shelf life cilembu sweet potatoes by minimize weight loss 8.91%, moisture content 66.02%, hardness 7.49 kgf, total dissolved solids 17.3oBrix, and brown spots 12.33%.
Keyword: cilembu sweet potatoes, corn starch, edible coating, red galangal, quality

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.
Keyword: