Judul: Exploration of Diversity and Analysis of Drosera Habitat and Microhabitat in Belitung Island
Abstrak: Drosera umumnya hidup di habitat khas miskin hara, seperti di hutan kerangas yang ada di Pulau Belitung. Penelitian ini bertujuan menginventarisasi dan memetakan persebaran jenis, serta menganalisis komposisi floristik habitat dan pengaruh mikrohabitat dan mikroklimat terhadap kelimpahan Drosera di Pulau Belitung. Inventarisasi dan pemetaan persebaran jenis dilakukan dengan metode jelajah. Kelimpahan Drosera, komposisi floristik habitat, serta karakter mikroklimat dan mikrohabitat diamati dengan membuat plot kuadrat di lima lokasi. Analisis Pearson correlation digunakan untuk mengetahui hubungan kelimpahan Drosera dengan data mikroklimat dan mikrohabitat. Hasil penelitian menunjukkan dua jenis Drosera (D. burmanni dan D. Spatulata) dijumpai di Belitung. Persebaran D. spatulata di Belitung merupakan catatan baru untuk Indonesia. Drosera dijumpai pada habitat yang memiliki kekayaan jenis rendah (21 jenis dari 14 famili) dengan Leptospermum polygalifolium, Melaleuca cajuputi, dan Calophyllum lanigerum sebagai pohon yang dominan. Habitat Drosera juga dicirikan dengan semak Baeckea frutescens dan Rhodomyrtus tomentosa (Myrtaceae) dan herba dominan dari famili Cyperaceae, Eriocaulaceae, dan Poaceae. Drosera dapat dijumpai pada substrat tanah lempung, pasir kuarsa, dan batu; tetapi lebih umum D. spatulata dijumpai pada tanah lempung dan D. burmanni pada pasir kuarsa. Kelimpahan Drosera dipengaruhi oleh kelembapan dan pH tanah, serta jumlah individu tumbuhan bawah. Luas penutupan tumbuhan bawah tidak mempengaruhi kelimpahan Drosera., Drosera commonly found in typical nutrient-poor habitats, such as the heath forest in Belitung Island. This study aimed to inventory and map distribution of species, analyze floristic composition of habitat as well as the impact of microhabitat and microclimate on the abundance of Drosera in Belitung Island. The inventory and mapping were carried out using the exploration method. Species abundance, habitat floristic composition, microclimate, and microhabitat of Drosera were observed by making quadrate plots at five locations. Pearson correlation analysis was used to determine the relationship between Drosera abundance and microclimate or microhabitat data. The results showed that two species of Drosera (D. burmanni and D. spatulata) occurred in Belitung. Drosera were found in habitats had low species richness (21 species, 14 families) dominated by Leptospermum polygalifolium, Melaleuca cajuputi, and Calophyllum lanigerum trees. The habitat of Drosera was also characterized by shrubs Baeckea frutescens and Rhodomyrtus tomentosa (Myrtaceae) and herbs species of Cyperaceae, Eriocaulaceae, and Poaceae. Drosera in Belitung are found on clay, quartz sand, and rock substrates, however D. spatulata was more common in clay soils and D. burmanni in quartz sand. The Drosera abundance was influenced by moisture, acidity of soil, and the number of individual undergrowth; but it was not affected by area covered by understorey.
Keyword: Belitung, diversity, Drosera, heath forest, microhabitat

Judul: Feed Source Potential Plants to Carrying Capacity Beekeeping Habitat (Apis dorsata) in Belitung District
Abstrak: Apis dorsata bee is one species of bee that produces honey. This species cannot be separated from the availability of plants that serve as a source of feed, namely nectar and pollen. The higher the potential of bee feed, the more bees produce honey because of the large availability of feed. These factors have the most important value in the carrying capacity of Apis dorsata bees. The development of the beekeeping business in the Belitung Regency causes an increase in the bee population, which will negatively impact if it is not accompanied by the availability of plant habitat as a source of feed. Therefore, information about the distribution pattern, abundance, and diversity of pollen and nectar-producing plants in the Belitung Regency needs to be known. Based on this background, this study aims to identify the composition, diversity, spatial distribution patterns, plant associations, influential environmental variables, and the potential area of nectar and pollen-producing plants as the carrying capacity of A. dorsata habitat. The diversity of plant species that produce nectar and pollen data was obtained from farmer information and direct observations. The spatial distribution pattern of nectar and pollen-producing plants and vegetation analysis using the purposive sampling method. Observation of the composition structure of the Apis dorsata habitat was made using a combination of observational plots between the method of pathways and nesting plots. The distance for each transect is 3 km. The profile diagram was created by determining the location in the sunggau group (labun) with a size of 20 × 20 m2 (400 m2 ). Habitat characteristics data is determined based on abiotic environmental factors: air temperature, humidity and light intensity, pH, and soil moisture. The collection of abiotic parameter data was carried out at every single sub-station on four repeats of each transect. Determination of habitat potential using MaxEnt v3.4.0 software using species presence data and environmental variables. The results showed 55 potential plant feed species for Apis dorsata, 40 species of nectar-producing, 40 species of pollen-producing, and 26 species of nectar and pollen-producing species. The level of species diversity (H') in Perpat Village is classified as medium to high with a value of (2.92 - 3.02). Kembiri Village is classified as moderate to high with a value of 2.57 - 3.09. From both locations, the diversity index in Perpat Village is classified as higher in all growth phases. The value of species dominance (C) from both locations in Perpat Village was more dominated by several species than in Kembiri Village. The value of species-level (E) in Perpat Village has a higher value where the higher the value of leveling, the more stable the species diversity in the community. Other research results showed that the association index value in Perpat Village is meager at 36.7% compared to 45.9% in Kembiri Village. Only a tiny percentage showed a very high degree of association in the first location at 18.3% and the second at 12.1%. The distribution of plants in Perpat Village and Kembiri di lokasi pertama sebesar 18,3% dan lokasi kedua sebesar 12,1%. Persebaran tumbuhan di Desa Perpat dan Desa
Keyword: habitat modeling, rafter, spatial distribution, vegetation analysis, vegetation profiles

Judul: Sintesis Paduan Ti-6Al-4Nb sebagai Matrial Implan Pengganti Komponen Tibial
Abstrak: Synthesis of Ti-6Al-4Nb alloy was done by melting using Tri Arc Melting Furnace. Each sample was remelted five times to ensure the homogenity. Aluminum and niobium addition were expected to stabilize α phase and β phase until the αβ-titanium alloy was resulted. Yet based on the experiment, it was α-titanium alloy resulted. α-titanium alloy was a Hexagonal Close Packed (HCP) crystalline structure which would be cracked if deformation non-uniaxial happens. The presence of oxygen in pure titanium significantly increased the hardness of titanium. The addition of aluminum was also able to increase the hardness of titanium alloy because aluminum more stabilize the α phase in the α-titanium alloy. The corrosion ressistance of titanium could be increased by adding aluminum and niobium. Titanium coating with HA/chitosan composite was also proved in decreasing the corrosion rate because it barried direct interaction between titanium alloy and corrotion solution.
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