Judul: Mathematical Modelling of Tropical Rain Forest Biodiversity.
Abstrak: The biodiversity of tropical rain forests is very rich in terms of number of species growing in the forest. In order to illustrate the dynamic of those species, the Tilman model was modified. The modified models were called : the exploitative competition and the colonization models. Based on analysis conducted, we obtained that the colonization model showed more diverse than the exploitative competition model, given that the rate of colonization species and the mortality were positively constant. The result of simulation using the software of MATLAB 6.5, the exploitative competition model showed that for the number of species were 2, 6, and 180, the time length required for the species would grow together were 162, 255, and 10.870 years respectively. For the colonization model, the time length required for the species would grow together were 312, 8.980, and 92.951 years respectively. It can be concluded that in the colonization model the time length required is longer than the exploitative competition model. The colonization model showed longer time compared to the exploitative competition model. This might due to an assumption that different species does not cause difference in terms of ability in competition. They were merely different in terms of the ability of gap creation in the site. In the exploitative competition model, it was assumed that the superior species would be dominant. Keywords : biodiversity, mathematical model, rain forest.
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Judul: Model Dinamika Struktur Tegakan Hutan Alam Bekas Tebangan di Provinsi Kalimantan Tengah, Kalimantan Barat, dan Kalimantan Selatan
Abstrak: Most of the natural forest areas in Indonesia are logged over areas, in which their stand structures are different from those of primary forests. The phenomenon of stand structure dynamics includes recruitment, upgrowth, and mortality. The sustainability of productive forests depends on, among others, forest growth capability, environmental characteristics and proper forest management techniques in accordance with the ability of forest dynamic process. The objective of this study was to obtain dynamic models for the stand structures of logged over natural forests for each diameter classes and tree species groups, and then used them to predict stand structures for the next few years by using a stand structure projection method. This study used periodical measurement data from 44 permanent sample plots (PSP), which were established in the logged over areas of 5 HPH (timber concession companies) in West Kalimantan, 1 HPH in South Kalimantan, and 12 HPH in Central Kalimantan Provinces. Each PSP was one hectare in size, and it had various logging times and measurement periods. Data processing was carried out in the four stages : 1) analyzing the stand growth of each PSP in a 3-year period ; 2) species grouping (i.e. Dipterocarp and Non-Dipterocarp) and diameter grouping into 11 diameter classes (starting from 10-14,99 cm up to 60 cm up; 3) calculating the number and basal area of trees for each species group at each PSP; and 4) analyzing the data by using regression analysis to derive prediction models for projecting the dynamic of stand structures. Results showed that the upgrowth models for Dipterocarpaceae had coefficients of determination (R2) ranging from 14.8% to 70.4%, while those for Non-Dipeterocarpaceae ranging from 12.0% to 92.2%. The fixed models had R2 ranging from 5.4% to 73.0% (for Dipterocarpaceae) and from 5.6% to 82.3% (for Non-Dipeterocarpaceae). For diameter classes with non significant relationships or R2 < 50%, the mean of proportions was used to calculate the probabilities of upgrowth and stay on such diameter classes. The projection result of stand structure dynamics up to 51 years showed that the number of trees was increase. However, the projected stand structures tended to not follow the common “inverse J” curve of stand structure. Therefore, the projected stand structures were only recommended for no more than 12 years, which was also the maximum limit of the after logging period as used for constructing the models.
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Judul: Pembuatan dan Karakterisasi Lapisan Tipis Copper oxide (CuO) Sebagai Sensor Gas
Abstrak: Lapisan tipis Copper Oxide (CuO) adalah bahan scmikonduktor yang memiliki sirat sangat scnsitif tcrhadap gas. mcngingat bahan tcrscbut sangat mud-ah mcngabsorpsi gas. DCllgan absorpsi gas ini akan l11crubah resistivitas lapisan tipis tersebut. Dalmn pcmbuatan.lapisan (ipis ini, lllclodc yang digunakan adalah metodc Dcposisi Fasa Cair (Liquid Phase Deposition) yaitu dengan mencmnpurkan 100 ml larutan Copper Sulphal (CuSO, 1I2H,O) 1M dengan 50 ml ammonium 25 %, Kemudian dicuplik 6ml dan dimasukkan ke dalam wadall yang telah terisi aquades 60 ml dan substrat pada dindingnya, kemudian diaduk dengan slirier dan dipanasi pada suhu 75°C selama 1 jam, Pendeposisian ini dilakukan sebanyak 4 kali. Hasil karakterisasi XRD memperlihatkan puncak-puncak CuO yaitu berada pada 28 = 35,306; 38,502; 61.475; 65,538 dengan masing-masing d = 2,5400: 2,3362: 1.5071; 1.4231.
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