Judul: Analisis hubungan faktor iklim dengan tingkat serangan wereng batang cokelat (Nilaparvata lugens Stal.) sebagai landasan prediksi serangan: studi kasus pada 3 Kabupaten di Provinsi Jawa Tengah
Abstrak: Pests are organisms that can cause damage to plants and can adversely affect the economy. Rice is the most important staple food in Indonesia. One of destructive pest of rice plants which can reduce the production is brown planthopper (Wereng Batang Coklat – WBC). One of the triggers widespread increase in attacks of WBC is the climatic factor. Climatic factors can influence the level of attacks of the pest. Therefore, the influence of climate on broad attack WBC is important to be analyzed. This study aims to analyze the relationship between climatic factors with a broad attack WBC as a basis for prediction of attack. The areas of studies covered 3 district of Central Java Province,e.g., Cilacap, Pekalongan, and Tegal. The method used for analysis linear regression method for rainfall, quadratic regression to other climatic factors, and multiple linear regression to all the climatic factors that possible influence. Analysis of climatic factors with broad WBC relationships attacks carried out at different time delay (lag time) those are without lag, lag 1 and lag 2. The highest determinate coefficient results between regions of WBC attacks and climatic factors is 20.2%. These results obtained when the analysis is done in lag 1 with the equation of LS (Area Of Attack) = - 38 + 90.2 Tavg - 36.0 Tmax - 61.6 Tmin - 0146 R + 3.11 RH. Climatic factor is one of the factors that influence the broad attack of WBC, there are several other factors that need to be included in the analysis to improve results and get a better prediction.
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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-Natrium Alginat untuk Aplikasi Direct Methanol Fuel Cell
Abstrak: Composite of chitosan and sodium alginate can be utilized as base material of proton exchange membrane (PEM). The composite membranes were produced by various concentrations of chitosan-sodium alginate, namely 3:3, 3:4, 3:5, 3:6, 4:3, 5:3, and 6:3 (% b/v). The composites were characterized by using Fourier transform infrared spectrophotometer (FTIR), scanning electron microscope (SEM), and were tested for the performance as PEM from the proton conductivity obtained by using impedance spectrometer. The FTIR spectrum indicated the NH3C group at 1637.29 cm-1 and symmetrical COO group at 1253.68 cm-1 indicating interactions between chitosan and sodium alginate. SEM micrographs showed that the composite membrane was nonporous. Composite membrane with 3:5 chitosan-sodium alginate composition had the highest proton conductivity, namely 9.594 × 10-7 S/cm. Based on this research results, chitosan-sodium alginate composite membrane can be applied well in direct methanol fuel cell system.
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