Judul: Komposisi Jenis dan Struktur Tegakan Hutan di Cagar Alam Dungus Iwul, Jawa Barat-Banten
Abstrak: Forests have a very big role, both as an imbalance of the ecosystem, increase the income of a country as well as support development in other sectors. Country that has a huge potential of forests is Indonesian. Forest destruction in Indonesia reached 2.8 million hectares per year of total forest area covering 120 million hectares that is spread all over Indonesia. Of the total forest area, about 57 to 60 million hectares of already degraded and the damage that Indonesia now has only forest in good condition about 50% of the total area available, while the forest area in West Java province decreased to less than 10 percent in 2010. Nature Reserves Dungus Iwul an illustration of the lowland forests. Research related to the high diversity of flora and ecological plants ever done by some researchers but scientific publications is not commonly found, that its presence seemed to have forgotten. Because biodiversity is still little information in the Nature Reserve Dungus Iwul, hence the need for a study to determine the degree of biodiversity and especially the type of tree. This study was conducted from January through February 2010 in the Nature Reserve of Dungus Iwul, West Java. This study was performed by using vegetation analysis technique which constitutes combination between strip method for tree stage vegetation inventory and plotted line method for forest regeneration inventory. Sampling units were placed in the field with sampling design of systematic sampling with random start. Based on the results, the highest number of plant species found on the smallest growth rate of saplings and poles at the level of growth. Iwul plant species (Orania sylvicola) is the dominant species at all type of plant with the different codominant species, Leea aequata for seedlings, Helicia serata at the level of sapling and poles, and Aporosa microcalyx at tree level. Diversity index (H') and evenness in Nature Reserves Dungus Iwul were high. The species richness was high for seedling, sapling and pole stages, however, is the middle level for tree stage. The structure of forest stands in CA Dungus Iwul characterized by increasingly large diameter stem the diminishing number of individuals. Forest vegetation in CA Dungus Iwul vertically composed of three strata. For all species irregular pattern showed clustered
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Judul: Komposisi Jenis dan Struktur Tegakan Hutan di Cagar Alam Sibolangit, Sumatera Utara
Abstrak: Forest is an ecosystem that combines the interaction between biotic and abiotic factors. Ecologically, the formation of forest community formed gradually through the changing of the vegetation and habitat. Community of forest is a dynamic and always changing until it reaches a optimum stage. The growth of a tree species in a forest community is influenced by several factors, including climatic factors, edaphic, physiological and biotic factors. The changing in the factors mentioned previously will take effect on the vegetation structure and composition. Forest with a variety functions and benefits provide a tremendous influence both directly and indirectly to several aspects such as ecology, economic, and social. Utilization of forests can be well manage and reach the sustainably if the information about the forest condition are available. Sibolangit Nature Reserve which is located in Deli Serdang regency. The existence of the Sibolangit Nature Reserve with high biodiversity information still limited, therefore it is necessary needed to have a study of nature reserve in order to explore the benefits and potency of the nature reserve without disturbing the presence and preservation of the forest. Hence, we need a study to in the Nature Reserve Sibolangit of the forest, analyze species the composition, and structure. This research conducted from December 2008 until January 2009 using vegetation analysis techniques with the transeet methods. As preliminary, the transeet divided into plots of 20m x 20m to inventory the trees, 10m x 10m to analyze the pole, 5m x 5m to inventory the saplings, and the 2m x 2m to inventory the seedling. For the sampling unit it uses a sampling design in the form of systematic sampling with random start. Based on the results of observation, the seedlings and saplings dominated by Sono keling (Dalbergia latifolia). While for the poles and trees dominated by Angsana (Pterocarpus indicus). The diversity value in Sibolangit Nature Reserve classified as medium diversity. In Sibolangit Nature Reserve, the highest Similarity Index values was found in the north-south slope and the lowest one found in north-eastern slopes. Forest vegetation Sibolangit Nature Reserve in vertical point of view consists of three strata, namely the stratum A (tree height over 30 meters), stratum B (tree 20-30 meters high), and stratum C (tree height 4- 20 meters), where most of the tree population is distributed in the canopy stratum from 11 until 20 meters. All individuals in the forest show clustered distributed at both the tree and forest regeneration level.
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Judul: Pemanasan sekunder plasma menggunakan gelombang mikro untuk reaksi fusi terkontrol
Abstrak: elah diteliti pengaruh pemanasan sekunder pada plasma dengan menggunakan gelombang mikro, yang dijalarkan tegak lurus dengan medan magnetik toroidal dalam tokamak. Didapat nilai numerik daya P =ψψm ≈ 1,305×10-15 W/m3 yang diserap oleh elektron per volume terhadap pemanasan sekunder menggunakan gelombang mikro yang penjalarannya tegak lurus dengan arah medan magnetik toroidal. Nilai yang kecil menunjukkan nilai rerata terhadap banyaknya partikel dalam plasma. Adapun diperolehnya nilai radius rm ≈ 1m yang mendapat nilai serapan terbesar menunjukkan bahwa pada lokasi tersebut terdapat sumbu magnetik, yang sebelumnya diasumsikan berada di pusat lingkaran penampang poloidal tokamak.
Keyword: sumbu magnetik, Gelombang mikro