Judul: Physical Properties and Drying Characteristics of Tamiang Bamboo using Oven, Steam Drying, and Air Drying Methods
Abstrak: Bambu merupakan tanaman cepat tumbuh yang termasuk kedalam komoditas hasil hutan bukan kayu. Salah satu jenis bambu yang potensial dimanfaatkan sebagai sedotan bambu adalah bambu tamiang (Schizostachyum blumei). Namun dalam proses pengeringannya terdapat beberapa permasalahan. Tujuan penelitian ini adalah pengaruh berbagai metode pengeringan terhadap sifat fisis dan sifat pengeringan bambu tamiang serta mengidentifikasi serangan dan jenis organisme perusak yang menyerang bambu tamiang pada saat proses pengeringan. Bambu tamiang dikeringkan dengan metode pengeringan oven, uap panas, dan alami. Pengujian sifat fisis yang dilakukan meliputi kadar air, perubahan warna, perubahan dimensi, serta penurunan berat selama proses pengeringan. Sifat pengeringan meliputi laju, waktu, dan cacat pengeringan. Metode pengeringan memberikan pengaruh yang nyata terhadap perubahan warna, perubahan kecerahan, penyusutan dimensi dan laju pengeringan. Sebanyak 17 sampel bambu tamiang yang dikeringkan alami mengalami serangan kumbang (Dinoderus minutus) dan 16 sampel diserang jamur pada bagian ujungnya. Deformasi diameter terjadi pada 9 sampel pengeringan oven, 4 sampel pengeringan uap panas, dan 3 sampel pengeringan alami., Bamboo is a fast-growing plant that falls under the category of non-timber forest products. One type of bamboo that is potentially useful for making bamboo straws is tamiang bamboo (Schizostachyum blumei). However, there are several issues in the drying process. The aim of this research is to study the effect of various drying methods on the physical properties and drying characteristics of tamiang bamboo and to identify the types of organisms that attack tamiang bamboo during the drying process.Tamiang bamboo was dried using oven drying, steam drying, and natural drying methods. The physical properties tested include moisture content, color change, dimensional change, and weight loss during the drying process. The drying characteristics studied include the rate, time, and defects of drying. The drying method has a significant effect on color change, brightness change, dimensional shrinkage, and drying rate. A total of 17 naturally dried tamiang bamboo samples were attacked by beetles (Dinoderus minutus), and 16 samples were attacked by mold at the ends. Diameter deformation occurred in 9 oven-dried samples, 4 steam-dried samples, and 3 naturally dried samples.
Keyword: bamboo straws, Dinoderus minutus, drying, moisture content, Schizostachyum blumei

Judul: Anatomical Structure of Tamiang Bamboo  (Schizostachyum blumei) Culm at Different Moisture Content Conditions
Abstrak: Informasi tentang perubahan struktur anatomi penyusun batang bambu setelah dikeringkan masih sangat terbatas, padahal sangat diperlukan untuk mendukung pemilihan proses dan kondisi pengeringan yang paling tepat. Penelitian ini bertujuan mempelajari struktur anatomi batang atau bilah bambu tamiang (Schizostachyum blumei) pada kondisi segar, kering udara dan kering oven. Bahan yang digunakan adalah 3 batang bambu tamiang yang berasal dari kebun masyarakat di daerah Semin, Wonosari, Gunungkidul, Yogyakarta umur 10 tahun. Struktur anatomi diamati secara makroskopis menggunakan USB dan mikroskop digital Keyence VHX 7000, lalu dianalisis dengan bantuan software J-image. Parameter yang diteliti meliputi kadar air, laju pengeringan, tebal bilah, porsi ikatan pembuluh dan jaringan parenkim dasar serta dimensi ikatan serat dan metaxylemnya. Hasil penelitian menunjukkan setelah dikeringkan, kadar air dan tebal batang bambu berkurang, namun komponen struktur anatomi utama penyusun bambu tidak berubah dan tidak mengalami perubahan bentuk. Tebal bilah menyusut sesuai dengan perubahan nilai kadar air. Penyusutan tersebut berkorelasi dengan menyusutnya ikatan serat yang ada didalam ikatan pembuluh., Information regarding changes in the anatomical structure of bamboo culms after drying is very limited, even though it is very necessary to support the most appropriate drying conditions. This research aims to study the anatomical structure of tamiang bamboo (Schizostachyum blumei) culms under three different conditions i.e. fresh, air-dried and oven-dried. The materials used were 3 culms of the 10-year-old tamiang bamboo from a community garden in Semin, Wonosari, Gunungkidul, Yogyakarta. The anatomical structure was analyzed macroscopically using a USB and confirmed by a Keyence VHX 7000 digital microscope, then analysed by using J-image software. Parameter studied consists of moisture content, drying rate, culm’s thickness, portion of vascular bundle and ground parenchyma tissue as well as the size of fiber bundle and metaxylem. After drying it showed that moisture content and thickness of the bamboo culm decreased, however the type and the shape of the main anatomical components did not change significantly. The thickness of bamboo culm decreases according to moisture content, and this shrinkage is correlated with the shrinking of the fiber bundles in the vascular bundle.
Keyword: anatomical structure, culm thickness, drying, moisture content, tamiang bamboo

Judul: Truncated Stop Loss as a Optimal Solution of Reinsurance Agreement in One-Period Model
Abstrak: Reinsurance is one of risk management efforts of an insurance company, which is called the cedent. Similar with insurance, reinsurance constitutes the cedent to pay the premium. We consider one-period reinsurance model and derive a rule which minimizes the ruin probability of the cedent for a fixed reinsurance premium. Therefore, it is needed to construct an optimal reinsurance agreement for the cedent. The premium is calculated according to four different principles, i.e. economic, generalized zero-utility, Esscher, and mean-variance principles. Stop loss is a reinsurance contract which protect the insurance company for losses that exceed a certain amount. The result of this research shows that a truncated stop loss is an optimal agreement in the class of all reinsurance contracts with various premiums calculated using above mentioned principles.
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