Judul: Detoxification of Cassava’s Acid Hydrolyzate by Activated Carbon Method for Bioethanol Production
Abstrak: Cassava is one of natural resources for carbohydrate that also available for bioethanol production. Starch and fibers hydrolysis maybe conducted on acid condition. The restriction in acid hydrolysis is 5-hydroxymethyl furfural (HMF) and furfural formation, which inhibit yeast fermentation. This study applied two stages of detoxification, which are overliming and activated carbon adsorption methods for lowering HMF and furfural concentrations. In order to obtain tolerable amount in sugar solution, detoxification by activated carbon adsorption was done by concentration of 1%, 2.5%, 5% and 10% and duration of contact are 30 45 and 60 minutes. The results showed that overliming method decreased HMF and furfural concentrations 34.38% and 60.81%, respectively. Overliming followed by 5% activated carbon adsorption for 30 minutes produced the best sugar solution which has a lower HMF and furfural concentrations by 72.03% and 89.11%, respectively. Adsorption constants of HMF and furfural by 5% activated carbon were 0.044 g/min and 3,7 x 10-5 g/min, respectively. The concentration of ethanol produced was 5.00% (b/v) or 63.22% higher than obtained from detoxification by neutralization (NH4OH) which produced ethanol only 3.06%.
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Judul: Process engineering of cassava pulp hydrolysis using microwave heating for ethanol production
Abstrak: Cassava pulp is a potential source of carbohydrates. In this work, characteristics of the cassava pulp were analyzed and validity of microwave irradiation for hydrolysis of carbohydrates, especially starch present in the cassava pulp, was estimated as a non-enzymatic saccharification technique. The hydrolysis was performed in water and acid medium. In addition, the role of activated carbon in the microwave-assisted hydrolysis was also evaluated. An optimization of the hydrolysis was conducted using Central Composite Design (CCD) and was analyzed using Response Surface Methodology (RSM). Fermentation of cassava pulp hydrolysates produced from microwave-assisted acid hydrolysis was performed to those added with activated carbon (25% w/w) and those without activated carbon by Saccharomyces cerevisiae. There were two types of activated carbon, which have different adsorption properties, used in this experiment. Results of the cassava pulp characterization shows that the starch granules in the cassava pulp were trapped in biomass matrices, so that the starch was harder to hydrolyze than the free starch, such as that in tapioca flour. Microwave-assisted hydrolysis of cassava pulp can be completed in less than 15 minutes in water medium, and less than 10 minutes in acid medium. The addition of activated carbon improved hydrolysis of cassava pulp starch in water medium with suppression of formation of the secondary decomposed materials. The highest glucose yield obtained from cassava pulp was 46% of dry matter or 52% of theoretical, which was about 60% higher than the one without the addition of activated carbon. On the contrary, the addition of activated carbon decreased the glucose yield when the hydrolysis was performed in acid medium (0.5% H2SO4). The glucose yield could reach 80.8% of dry matter or 91.5% of theoretical yield when no activated carbon was added in the acid medium. The estimated optimum condition for cassava pulp hydrolysis under microwave irradiation was using 0.88% sulfuric acid with 9 minutes of heating time, which resulted in 85% of theoretical glucose yield and 140 g/L glucose concentration. At the end of the fermentation the ethanol yield and concentration obtained in the samples treated with activated carbon (0.41-0.43 g ethanol / g glucose consumed; 34-35 g/L) were lower than that not treated with activated carbon or those treated with activated carbon which was added after hydrolysis (0.48 g ethanol / glucose consumed; 38- 39 g/L). However, the fermentation was completed very much faster in the hydrolysates treated with the activated carbon which has a high adsorption capacity than in that not treated with activated carbon or those treated with activated carbon of low adsorption capacity. Therefore, ethanol productivities (0.44-0.55 g/L/h) of the former were higher than the latter (0.28-0.34 g/L/h).
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Judul: Kecepatan Terbang Burung Merpati Balap Lokal (Tipe Tinggian)
Abstrak: Penelitian ini dilaksanakan di wilayah Jakarta, tepatnya Rawamangun Selatan, Gg. Kana Tanah Merah Lama, Jakarta Timur. Ternak yang digunakan dalam penelitian ini adalah 46 ekor burung merpati lokal terdiri dari 23 pasang burung merpati jantan dan betina yang berumur 9 bulan samapi 12 bulan. Jarak melepaskan burung merpati pada penelitian ini sekitar 4 km. Waktu terbang diukur dengan cara sewaktu burung merpati dilepas dari tempat diterbangkan, joki yang melepas memberi aba-aba melalui handphone kepada joki yang berada di kandang bahwa burung merpati siap dilepas. Peubah yang diamati adalah karakteristik kualitatif, kecepatan terbang, pola terbang dan ukuran tubuh burung merpati balap tipe tinggian. Data disajikan secara deskriptif tentang karakteristik kualitatif, kecepatan terbang, pola terbang dan ukuran tubuh burung merpati balap tipe tinggian. Rataan, simpangan baku dan koefisien keragamannya dihitung untuk mengetahui keragaman dan keseragaman pada ukuran tubuh burung merpati balap tipe tinggian dengan menggunakan rumus koefisien keragaman (Walpole, 1992). Kecepatan terbang burung merpati balap tipe tinggian dilakukan selama tiga kali giring. Kecepatan antar periode giring diuji dengan uji t dengan menggunakan rumus (Walpole, 1992). Nilai koefisien keragaman (KK) dari yang paling besar sampai paling kecil adalah lebar pangkal ekor (12,37%), panjang bulu ekor (10,27%), panjang punggung (9,43%), lebar bulu ekor (9,27%), bobot badan (8,15%), dalam dada (7,41%), panjang bulu sayap (7,17%), lingkar dada (3,62%) dan lebar dada (3,48%). Berdasarkan urutan tersebut, maka ukuran tubuh yang paling beragam adalah lebar pangkal ekordan yang paling seragam adalah lebar dada. Lebar pangkal ekor dapat dijadikan penentu seleksi burung merpati balap tipe tinggian karena berpengaruh nyata negatif (P<0,05) terhadap kecepatan terbang burung merpati balap tipe tinggian. Kecepatan terbang merpati tidak berbeda nyata antara periode giring satu dengan periode giring yang lain, hal ini menunjukan bahwa setelah burung merpati dilatih maka kemampuan terbangnya cenderung stabil. Hasil analisis korelasi untuk lingkar dada, lebar dada, panjang punggung, panjang bulu sayap dan panjang bulu ekor tidak menunjukkan hubungan yang nyata dengan kecepatan terbang. Bobot badan, dalam dada, lebar bulu ekor dan lebar pangkal ekor menunjukkan hubungan yang nyata dengan kecepatan terbang. Pada pengamatan di lapang diperoleh beberapa pola terbang burung merpati balap tinggian yaitu 1). Pola berputar lalu terbang lurus (burung merpati warna kelabu dan tritis) dengan kecepatan rata-rata masing-masing 18,69 dan 18,65 m/detik, 2). Pola langsung terbang lurus (burung merpati warna megan, hitam, gambir dan megan 2). Dengan kecepatan rata-rata masing-masing 23,62; 25,39; 28,88 dan 29,18 m/detik, 3). Terbang lalu ditengah perjalanan dahulu setelah itu terbang lurus (burung merpati warna blorok, tritis megan, blantong dan kelabu selap) dengan kecepatan rata-rata masing-masing 20,18; 20,21; 21,94 dan 21,94 m/detik. Burung merpati balap tinggian yang memiliki kecepatan terbang tertinggi (29,18 m/detik) mempunyai pola terbang langsung terbang lurus, bobot badan (330 g), lingkar dada (22 cm), dalam dada (5,4 cm), lebar dada (8 cm), panjang punggung (12 cm), panjang bulu sayap (18 cm), lebar bulu ekor (4,4 cm), lebar pangkal ekor (3,5 cm) dan panjang bulu ekor (11 cm).
Keyword: high racing pigeon, flight pattern, flight speed, quantitative characterstics