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: Process-Based Modelling of Growth and Carbon Sequestration of Young Teak (Tectona grandis L.f.)
Abstrak: The objectives of the research are : 1 ) To understand the processes in phenology, growth, and water balance of teak and its interaction with environmental factors, as the basis for designing quantitative relationships in modelling activity, 2) To caiibrate a process-based model that can describe the relationship between teak growth and soil water availability, 3) To predict the carbon sequestration of teak. The research consists of a modelling project and a field experiment to obtain model parameters. The model consists of three sub-models, 1.e. development, growth, and soil water balance. The objective of the mdel is to simulate teak growth, development and carbon sequestration as affected by soil moisture regime and weather variables. The model predicts individual teak growth, development and carbon sequestration on a daily time step. The field experiment was conducted for two years in Jakarta, with three levels of irrigation: control (0) , 7 and 14 mm day-' to reflect varymg seasonal water regime. The measurements included pheno fogy,i. e. : leaf emergence and drop, growth, i. e. : biomass production, arbon content, w d density, stem height diameter and volume, leaf number and leaf area index, climate variabies, i.e. : rainfall and solar radiation, and soil water content. The climatological data to run the model was obtained from the Climatological Station at Pondok Betung, Tangerang, Province of Banten, Indonesia. The results show that soil water availability affected teak development and growth. Leaf emerged regularly after reaching a thermal unit of 265 dd in the nonwater deficit condition. Leaf dropped regularly in wet and dry seasons after reaching a thermal unit of 460 dd. Water deficit inhibited leaf emergence and fasten leaf drop for the plants that always received excessive water input. Water deficit reduced biomass production, stem diameter and height, stem volume, light use efficiency. leaf number and leaf area index. Water availability did not affect carbon sequestration by teak. The excessive of water tended to reduce wood density. As water deficit affected growth and development, biomass prduction in the model was corrected by a water availability factor. The water availability factor used in this model is the ratio of actual and maximum transpiration. The process-based model built in this research can describe the dynamics of early growth stage of teak especially for leaf emergence, stem diameter, height, wood volume and soil moisture content. The model is sensitive to water availability but still cannot describe adequately the dynamics of biomass and carbon content, leaf area index and number. The water availability factor is not enough to describe it. The mdel needs to be improved and validated with a different data set.
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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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