Judul: Pendekatan Model Fuzzy untuk Pendugaan Bobot Badan Kerbau Lumpur Berdasarkan Lingkar Dada dan Panjang Badan
Abstrak: Body weight of a swamp buffalo can be determined by measuring the buffalo weight directly or indirectly. Measuring the buffalo weight directly is relatively difficult. Measuring the weight indirectly can be performed using a conventional formula or fuzzy model. In this paper, a fuzzy model is used to estimate the body weight of a swamp buffalo, then the result is compared with the result of calculation using four conventional formulas. There are some steps being taken on deriving the fuzzy model, namely fuzzification, application of implication function, composition of rules, and defuzzification. Inputs used in this fuzzy model are the chest circumference and the body length. The output of this model is the body weight. The accuracy of estimation based on conventional formula and fuzzy model is compared by using mean absolute percentage error (MAPE). Based on the value of MAPE, it can be concluded that the fuzzy model is relatively better than the first three of conventional formulas, but it is not better than the fourth formula.
Keyword: MAPE, fuzzy model, swamp buffalo

Judul: Aplikasi Ukuran Linier Tubuh Sebagai Penduga Bobot Badan pada Kerbau Rawa.
Abstrak: Penelitian ini bertujuan untuk memprediksi bobot badan kerbau rawa melalui ukuran linier tubuh. Tinggi badan (TB), tinggi pinggul (TP), lingkar dada (LiD), lebar dada (LD), dalam dada (DD), lebar pinggul (LP), panjang kelangkang (PK), lebar kelangka (LK), panjang badan (PB) diukur dalam satuan cm menggunakan pita ukur, penggaris 1 m dan tongkat ukur, sedangkan bobot badan ditentukan dalam kg dengan menggunakan timbangan 2 ton. Perbandingan rataan ukuran tubuh antara kerbau jantan dan betina dianalisis melalui analisis uji-t. Hubungan antar variabel ukuran linier kerbau dianalisis melalui analisis korelasi. Pendugaan bobot badan diestimasi melalui analisis regresi best subset, linier dan linier ganda. Hasil analisis uji-t menunjukan kerbau jantan dan betina memiliki perbedaan yang nyata pada lingkar dada, tinggi pinggul, dan panjang badan. Pendugaan bobot badan pada kerbau rawa dapat diestimasi melalui regresi linier ganda dengan variabel penduga lingkar dada dan tinggi pinggul. Hal tersebut dapat disimpulkan bahwa bobot badan kerbau dapat diduga menggunakan rumus regressi linier ganda, BB = 3.6435LiD + 0.1208TP - 265.43 untuk kerbau rawa jantan dan BB = 4.1783LiD – 0.3086TP – 305.19 untuk kerbau rawa betina.
Keyword: koefisien korelasi, ukuran linier tubuh, kerbau rawa

Judul: Application of phycocyanin from microalgae Spirulina platensis as light harvesting in anatase TiO2 nanoparticle solar cell.
Abstrak: The dye sensitized solar cell (DSSC) has been assemblied used hybrid titanium oxide (TiO2) film/phycocyanin. The TiO2 film was synthesized by sol gel method with titanium chlorida (TiCl4) as precursor by hydrolysis used sulfuric acid (H2SO4). Furthermore, it calcinated for 2,5 hours in variation of annealing temperature (400oC, 600oC, 800oC, dan 1000oC). In XRD patterns exhibited which annealing temperature at 400oC to 800oC were anatase phase all. When annealed at temperature 1000oC, it caused phase transformation from anatase to rutile. The crystals size according to XRD patterns were 13,75 nm, 20,79 nm, 25,25 nm, 48,88 nm and particle size from SEM images were 43,06 nm, 44,91 nm dan 64,99 nm, 80,40 nm, respectively. The crystals and particle size increased with annealing temperature. The film thickness influenced material absorption. The optical measurement of TiO2 film and TiO2/phycocyanin hybrid film used UV-Vis spectrophotometer. Additional phycocyanin caused peak width of absorbed region from ultraviolet to visible region. The band gap energy of TiO2 can be calculated using the cut off wavelength obtained from the absorbance spectrum of a nanoparticles TiO2 films. Based on intersection between linear and energy (hv) axis. In this study just limited for anatase phase. It was caused anatase band gap is wider than rutile phase. That’s meaningful for solar cell application such as dye sensitized solar cell (DSSC). The absorption coefficient average at difference annealing temperature such as at 400oC, 600oC, 800oC were 8,1600x102, 1,7535x103 and 4,0154x102, where α < 104 include to direct transition. Band gap energy 400oC, 600oC, 800oC were 3,79 eV, 3,59 eV, and 3,35 eV, respectively. Based on this result, exhibition that band gap energy of TiO2 semiconductor film decreased with increasing annealing temperature. Spirulina platensis was cultivated in technical modification (Hastuti) with aeration under light intensity about 3000 lux. The cell density (stationer phase) for eighth day which OD value was more than 0,5. It means, the culture can be harvested. In 80 liters Spirulina platensis culture have been produced biomass dry about 10,46 gram and extracted phycocyanin in dry powders was 5,50 gram. The phycocyanin absorption spectrum at the wavelength of 619,36 nm (visible region) which had relaxation energy was 2,945 eV. The emission peak at the wavelength of 708,55 nm with relaxation energy about 2,793 eV. The Stokes shift based on difference energy absorption and emission calculated about 0,152 eV. Both of this showed phycocyanin can absorbed and radiated the sun light which received. This choice characteristic pigment was a good one related to sensitizer in solar cell application. Integration between light harvesting protein and TiO2 semiconductor surface had important role in improving of output as solar cell materials. The presence of carboxylate group (-COOH) made pigment be more efficient was due to anchored to the surface of TiO2 ampoter. The phycocyanin pigment had carboxylate group which reacted with TiO2 surface formed ester. The carboxylate group increased of dye electronics couple from excited state (p anti bonding orbital) to semiconductor acceptor state (TiO2 conduction band). The samples which made based on annealing temperature variation formed be solar cell respectively. Furthermore, cells be assembled for
Keyword: anatase, dye sensitized solar cell, efficiency, gap energy, phycocyanin