Judul: Pemanfaatan Pod Kakao untuk Produksi Etanol melalui Hidrolisis Menggunakan Kapang Aspergillus niger dan Trichoderma viride
Abstrak: Indonesia is one of the largest cocoa producing country in the world, and according to harvest data from 2005, Indonesia produces 13% cocoa from the total world cocoa demand. Fresh cocoa fruit consists of 75.50% of the fruit shells, 21.18% of seeds and 2.60% of placenta. Cocoa pod is one of lignoselulosic waste containing of 31.25% cellulose. The cellulose composition large enough to make cocoa pod potential to be processed into ethanol. So far, ethanol production is more focused on raw materials such as cassava, sweet potatoes, sugar cane, sago, and several types of starch which is less effective because these materials compete with food. This research aimed to find out the effects of substrate’s type of cocoa pod, the type of mold, and time of hydrolysis optimized to produce high levels of reducing sugar and producing ethanol from the best hydrolisate. This research were performed into three stages. The first stage was the preliminary stage that includes the characterization of cocoa pods and pretreatment on cocoa pod including reduction in size, degumming, and delignification. The second stage was the hydrolysis of cocoa pod using two types of fungus (Aspergillus niger and Trichoderma viride), two types of substrates (non-delignified and delignified cocoa pods), hydrolysis time (11 days), sampling on days 1, 3, 5, 7, 9, and 11. Last stage was the fermentation using the best hydrolisate, using Saccharomyces cerevisiae culture. This research utilized completely randomized factorial design with three factors and two replications. The first factor was the type of fungus, which consists of two levels of Aspergillus niger and Trichoderma viride. The second factor was the hydrolysis time with 6 degree of day (1, 3, 5, 7, 9, and 11). The third factor was the type of substrate with two levels of the substrate non-delignified and delignified cocoa pods. Material characterization results obtained the cellulose content of cocoa pods is 28.78% (wb), Hemicellulose 8.70% (wb) and 42.90% lignin (wb). After delignification the results obtained cellulose content is 32.23% (wb) and 31.00% lignin (wb). The delignification efficiency was 27,74%. Based on the results of range analysis with α <0.05 at the hydrolysis stage substrate types affected significantly on reducing sugar concentration, whereas the type of fungus and hydrolysis time does not affect real.
Keyword: 

Judul: Kajian Pemanfaatan Pod Kakao (Theobroma cacao) melalui Hidrolisis Asam Lignoselulosa untuk Menghasilkan Etanol.
Abstrak: Cocoa is one of commodities that its role is important enough for the national economy. Cocoa commodity exports ranked third in the agriculture sector contributes foreign exchange, after the rubber and palm oil. Currently Indonesian cocoa production ranks third largest after the Ivory Coast and Ghana. In 2006 cocoa exports reached U.S. $ 975 million, an increase of 24.2% over the previous year (Suryani and Zulfebriansyah, 2005). Increased efforts in the field led to increased cultivation of cocoa pod waste. This is a challenge, given the amount of cocoa pod components for 73.73% of the cacao fruit (Siswoputranto, 1983). If the cocoa pod is not handled properly it will result in losses. In the research is studied on the acid hydrolysis using cocoa pod to produce ethanol. In addition to get the best treatment of acid hydrolysis that is affected by acid concentration and hydrolysis time and to get the highest yield of sugar and ethanol. This research was conducted in three main stages that were preliminary treatment of raw material preparation and characterization of raw materials, acid hydrolysis, and fermentation to produce ethanol. Hydrolysis of cocoa pod is done in two stages using sulfuric acid. In the first hydrolysis used sulfuric acid concentration of 1% with a time of hydrolysis for 1, 2, 3, 4, 5, 6, and 7 hours. In the second hydrolysis using acid with higher concentrations of 5, 10, 15, and 20% with hydrolysis time of 1, 2, 3, 4, and 5 hours. Analysis was conducted on the reducing sugar, total sugar, dextrose equivalent, and fiber components of lignocellulose. Fermentation using two different substrates derived from the hydrolysis of the first stage and second stage. In fermentation measured volume of CO2 formed, ethanol content, total residual sugar, the efficiency of substrate utilization and product yield of ethanol. On the characterization of raw materials obtained value of cocoa pod ash content 1.87% (db), fat 3% (db), protein 2.25% (db), carbohydrate 92.89% (db), and 53.82% crude fiber (db). Crude fiber fraction containing cellulose 28.78% (db), hemicellulose 8.70% (db) and lignin 42.90% (db). In the first hydrolysis, the results of analysis showed that the highest reducing sugar of 27.31 mg/ml was produced from treatment of 1% sulfuric acid and hydrolysis time of 4 hours. The highest total sugar also produced from the same treatment with a value of 32.74 mg/ml. Dextrose equivalent values ranged from 50.63% to 84.32%. On analysis of lignocellulose after the first hydrolysis, there is a decrease of lignin content, hemicellulose, and cellulose so that its value in a row to 30.82%, 6.52% and 25.75%. In the second hydrolysis, the best treatment that produces the highest reducing sugar and total sugar by using 5% acid concentration and time of hydrolysis for 4 hours. This treatment produces reducing sugar 15.91 mg/ml and the total sugar 29.26 mg/ml. In the second hydrolysis dextrose equivalent values ranged from 47.08% to 89.67%. Lignocellulose fiber components of cocoa pod is decreasing because the second hydrolysis, so that the lignin content to 28.88%, 4.45% hemicellulose, and cellulose 21.98%.
Keyword: 

Judul: Teknik penentuan posisi bintang berdasarkan pelat foto overlapping
Abstrak: Bintang adalah salah satu objek langit yang menarik untuk diamati. Untuk itu, pengetahuan tentang posisi bintang sangat diperlukan. Posisi bintang di langit dapat dihitung melalui foto bintang. Fotografi astronomi atau astrometri merupakan ilmu yang mempelajari metode untuk menentukan posisi bendabenda langit seperti bintang berdasarkan pelat foto (Kamp, 1967). Sebuah pelat foto berisi citra bintang-bintang yang sudah diketahui posisinya berdasarkan katalog dan citra bintang-bintang yang belum diketahui posisinya. Posisi bintang yang ada di katalog dinyatakan dengan (a,3). Bintang yang belum diketahui posisinya lebih banyak jumlahnya daripada bintang yang sudah diketahui posisinya. Citra bintang pada pelat foto berupa sebuah titik dalam bentuk tetap. Posisinya pada pelat merupakan hasil pengukuran pada bidang kartesius dan dinyatakan dengan (1;,fl). Hasil pengukuran tersebut kemudian direduksi menjadi koordinat terukur (x,y). Hubungan antara (a,3) dan (x,y) didekati dengan sebuah deret dengan konstanta-konsranta deret merupakan konstanta pelat. Nilai konstanta pelat diperoleh dengan menggabungkan hasil pengukuran posisi bintang pada masing-masing pelat menjadi sebuah persamaan normal (Jefferys, 1963). Hasil akhir dari gugus persamaan normal tersebut dijabarkan dalam bentuk nOlasi matriks partisi dan berupa sebuah sistem persamaan linier Ax = b di mana A adalah matriks jarang, dan x merupakan konstanta pelar yang akan dicari nilainya. Untuk menyelesaikan sistem persamaan linier terse but digunakan metode transformasi given. Konstanta pelat yang sudah diperoleh dengan menyelesaikan sistem persamaan linier di atas, kemudian disubtitusi ke sebuah persamaan untuk memperoleh posisi bintang yang tidak tercantum dalam katalog. .
Keyword: