Judul: Systematic Review: Condition and Challenges Harvesting Non-timber Products in Indonesia
Abstrak: Pemanenan HHBK merupakan kegiatan yang memanfaatkan hasil hutan berupa tumbuhan selain kayu dan hewan. Masyarakat yang tinggal disekitar hutan banyak memanfaatkan HHBK untuk memenuhi kebutuhan sehari-hari. Penelitian bertujuan untuk mengetahui bagaimana kondisi dan tantangan dalam pemanenan HHBK di negara Indonesia. Penelitian dilakukan menggunakan metode systematic review dengan jumlah 48 artikel. Pengumpulan artikel open acces yang ditulis dalam Bahasa Indonesia dan Bahasa Inggris. Pemanenan HHBK di Indonesia dilakukan pada hutan produksi. Pemanenan banyak dilakukan oleh masyarakat dengan manfaat bahan pangan. Pengambil HHBK banyak dilakukan secara berkelompok oleh masyarakat dengan waktu pemanenan yang beragam. Pemanenan HHBK di Indonesia mempunyai tantangan dalam peningkatan nilai tambah, pembentukan kelompok pemanenan, dan inventarisasi HHBK. Jarak panen yang semakin jauh membutuhkan waktu yang lama dan tenaga yang lebih besar., NTFP harvesting is an activity that utilizes forest products in the form of plants other than wood and animals. Communities living around the forest use NTFPs to meet their daily needs. This study aims to determine the conditions and challenges in harvesting NTFPs in Indonesia. The study was conducted using a systematic review method with a total of 48 articles. Collection of open access articles written in Indonesian and English. NTFPs are harvested in Indonesia in production forests. Harvesting is mostly done by the community with the benefit of food. NTFPs are mostly taken in groups by the community with various harvesting times. NTFP harvesting in Indonesia has challenges in increasing added-value, forming harvesting groups, and NTFP inventory. Longer harvest distances require more time and more energy.
Keyword: Pemanenan HHBK, Pendapatan HHBK, Tantangan HHBK

Judul: Systematic Review: Techniques, Produvtivity, and Costs of Harvesting Forest in Indonesia
Abstrak: Pasokan kayu selama ini berasal dari hasil pemanenan hutan alam dan hutan tanaman. Penelitian mengenai pemanenan kayu sudah banyak dilakukan di Indonesia dengan variasi hasil yang berbeda. Penelitian ini bertujuan untuk menghimpun hasil penelitian mengenai teknik, produktivitas, dan biaya pemanenan hutan di Indonesia. Data sekunder dihimpun menggunakan metode Systematic Review kemudian dianalisis menggunakan analisis deskriptif. Berdasarkan hasil pencarian secara online terhimpun 51 artikel penelitian mengenai pemanenan kayu di Indonesia yang kemudian dikelompokan menjadi tiga tipe hutan yaitu, hutan tanaman lahan basah, hutan tanaman lahan kering, dan hutan alam. Hutan tanaman lahan kering merupakan jenis hutan yang paling banyak diteliti. Kegiatan pemanenan dibagi menjadi beberapa tahapan antara lain penebangan, penyaradan, muat bongkar, dan pengangkutan. Kegiatan yang paling banyak diteliti adalah penyaradan. Produktivitas pemanenan dipengaruhi oleh peralatan pemanenan, kondisi lapang, teknik pemanenan, keterampilan pekerja, beban kerja, dan cuaca. Besarnya biaya pemanenan di pengaruhi oleh produktivitas, biaya pemilikan, biaya operasional, dan upah pekerja., The supply of wood so far has come from harvesting natural forests and plantation forests. Many studies on timber harvesting have been carried out in Indonesia with varying results. This study aims to compile research results on techniques, productivity, and costs of forest harvesting in Indonesia. Secondary data was collected using the Systematic Review method and then analyzed using descriptive analysis. Based on the results of an online search, 51 research articles on timber harvesting in Indonesia were collected which were then grouped into three types of forest, namely, wetland plantation forest, dry land plantation forest, and natural forest. Dryland plantation forest is the most studied forest type. Harvesting activities are divided into several stages, including logging, skidding, loading and unloading, and transportation. The most researched activity is skidding. Harvesting productivity is influenced by harvesting equipment, field conditions, harvesting techniques, worker skills, workload, and weather. The amount of harvesting costs is influenced by productivity, ownership costs, operational costs, and worker wages.
Keyword: biaya pemanenan, produktivitas pemanenan kayu, teknik pemanenan

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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