Judul: Study on the impact of climate variability on rice pest distribution and status shift in the Northern Coast of West Java
Abstrak: Every degree of earth temperature increasing will cause the life cycle of most insect pests to be speeded up. This equates to shorter time from egg hatching to full grown adult, thus creating larger pest populations. In the end, this will affect the distribution pattern and magnitude of pest invasion in the field. Brown plant hopper (BPH) and rice stem borer (RSB) are the two main types of rice pest that always gets attention from farmers due to the high damage caused by both pests. This study was aimed to analyze the impacts of climate variability on the distribution and pest status shifts of rice pests. An index of pest infestation was calculated to assest the status shift of a pest and a multiple regression technique was used to investigated the effect of climate variables on the magnitude of the pests (BPH and RSB) infestation. There was an increasing in earth temperature but a decreasing in precipitation in three districts of the Northern Coast of West Java during the period of 1990-2010. Contrary to the above two variables, the relative humidity was indicating a stable fluctuation over the period. Not all of the studied pests (Rats, BPH, RSB, and Leaffolder) indicated shifts in their status but only Rats and BPH did as the climate changed. Among the three climate variables, only the minimum temperature had a consistent effect on the infestation area of BPH and RSB. The infestation areas of BPH and RSB were increasing as the minimum temperature increased. The relative humidity had a similar but less consistent effect as the temperature effect on the pests infestation areas. The effect of precipitation on the pests infestation areas was not appearing to be significant in this study.
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Judul: Analisis Pengaruh Faktor Iklim Terhadap Tingkat Serangan Hama Wereng Cokelat (Studi Kasus: Kabupaten Karawang)
Abstrak: Brown Planthopper (Nilaparvata lugens Stal) is one of the limiting factors that cause decline in rice production. Based on existing data, the highest level of infestation occurred in 1998 in three areas of West Java, namely Karawang, Subang, and Indramayu at a total of 40.000 ha. The purpose of this study was to determine the effect of climatic elements on the level of infestation by brown planthopper on rice plantation in Karawang Regency. Climatic elements are used as the independent variable (x) and area infested by brown planthopper as the dependent variable (Y). A quadratic regression and multiple regression were used for the analysis. Quadratic regression analysis is used to express the relationship between the area infested and the climatic elements. Multiple linear regression analysis was performed to obtain the relationship of five climatic factors, namely the maximum temperature, minimum temperature, average temperature, humidity, and rainfall as a whole against area infested by brown planthopper. Climatic element that had the most influence was the minimum temperature with the value of the coefficient of determination (R2 = 17.6%) and with the regression equation of LS = - 8276 + Tm 797.6 - 18.69 TM2. The equation obtained from multiple regression analysis was LS = 905 - 28.0 Tr - 0:12 RH + CH 0210, with R2 = 7.2 %. These results suggested that there was a weak relationship between the area of infestation and the climatic elements.
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Judul: Membran Komposit Kitosan-Zeolit untuk Aplikasi Direct Methanol Fuel Cell
Abstrak: Direct methanol fuel cell (DMFC) is a fuel cell that utilize methanol as the fuel source. The electrolyte membrane used in the DMFC system in this research was chitosan-zeolite composite membrane. The composite membrane was synthesized with chitosan-zeolite composition variation of 1:1, 1:2, 1:3, and 2:1. The membranes were analyzed by Fourier transform infrared spectrophotometer (FTIR) and scanning electron microscope, and for the specific gravity. Membrane performances were tested with methanol uptake, methanol permeability, conductivity, and potential difference in the DMFC system. The FTIR spectrum showed no formation of new functional groups inducating that the composite membrane was a result of physical mixing. Morphological analysis showed that the membrane was nonporous. Chitosan-zeolite 1:3 composite membrane had the highest specific gravity and methanol uptake, 1.4226 g/mL and 41.44%, respectively. The highest proton conductivity was showed by the 1:2 chitosanzeolite composite membrane, namely 7.2946× 10-7 S/cm. Based on this research results, chitosan-zeolite composite membrane can be applied in DMFC system.
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