Hasil Pencarian  ::  Simpan CSV :: Kembali

"The decrease of rice-field area is one of causes of decreasing rice production in Indonesia. Physical development in many sectors has been converting rice field area into others such as industry, high ways, settlement and other agricultural areas. Because of limited possibility to extent rice field area, one of the efforts of increasing rice production is to implement intensification program. Rice paddy intensification program relates to "green revolution". Reaching success in 1984 indicated by rice self sufficiency in the year of 1984. This modernization is considered of new rice farming technology application, which is popular by the term of Panca Usaha Tani (Pranadji, 1993). Five elements of Panca Usaha Tani are well soil preparation, prime seed, irrigation sufficient and regular, optimal application of fertilizer and pesticide. Karawang is one regency in West Java Province that considered as one of national rice producing areas. This region is strategic, because it is relatively flat and located in the area of Jatiluhur irrigation. These are the reasons of Karawang chosen as a model of rice paddy intensification program. The research title is "Pemodelan Indeks Tingkat Keberhasilan Intensifikasi Sawah di Kabupaten Karawang MT 1998/1999 dan MT 1999". The objective of the research is to determine successfulness index of rice paddy intensification in Karawang Regency. The index is based on qualification of existing soil quality, efforts conducted, and rice production. By comparing each index of each kecamatan, it can be seen level of successfulness of the kecamatan in implementing intensification program, and it can be identified what factors must be improved in order to increase rice production in those kecamatan. The research questions are (1) Where is the highest and lowest of successfulness index in Karawang on growing season of the year 1998/1999 and 1999? and (2) How is the consistence of the index? The research method employed is GIS, using overlay, classification and scoring techniques with kecamatan as analytical unit. The results indicate that the highest indeces are in the southern part of Kabupaten Karawang, especially in the area of "excellent" and "poor" soil quality. Those are Kecamatan Cikampek and Telukjambe. The lowest indices are in the Northern and central of Karawang Regency, particularly on the "excellent" soil quality, Those are Kecamatan Tirtajaya and Rengasdengklok. The results also indicate that the values of indices are consistence in measuring the level of successfulness in rice paddy intensification program in Karawang Regency in growing season of the year 1998/1999 and 1999. "

"Dekomposisi termal batubara Muaro Bungo Jambi dianalisis menggunakan TGA/DTG dengan laju pemanasan 10oC/menit menggunakan nitrogen sebagai gas pembawa. Parameter kinetika dicari dengan memakai model Arrhenius. Senyawa hasil dekomposisi dianalisis dengan menggunakan pyrolysis-GC-MS. Dari data TGA/DTG diketahui bahwa batubara Muaro Bungo Jambi merupakan batubara dengan peringkat sub-bituminus. Terdapat tiga tahap dekomposisi yang terjadi. Tahap II menentukan kualitas batubara akibat adanya perlakuan oksidatif. Reaksi oksidasi menyebabkan temperatur maksimum tahap II dekomposisi bergeser ke arah temperatur yang lebih rendah, dan menghasilkan jenis volatile matter baru. Nilai energi aktivasi (Ea) dari batubara aglomerasi yang lebih rendah meningkatkan kereaktifan terhadap oksigen yang menyebabkan terbentuknya produk dengan gugus karboksil dan alkohol lebih banyak. Walaupun tingkat oksidasi batubara aglomerasi lebih besar, tetapi penurunan sifat caking batubara tidak mempengaruhi kualitas batubara. Hal ini dapat dilihat dari nilai faktor Arrhenius yang lebih kecil, yang mengindikasikan penurunan kadar volatile matter batubara pada tahap II tidak terlalu besar. Dari analisis senyawa hasil dekomposisi, batubara dapat digunakan sebagai sumber bahan baku senyawa kimia, atau bahan bakar tidakl angsung/sekunder.

---

The thermal decomposition of Muaro Bungo Jambi Coal has been analyzed using differential thermal gravimetry (DTG) with nitrogen as the gas carrier. The heating rate was 10oC min-1. An Arrhenius model is established to describe the kinetics parameter of coal. Pyrolysis-GC-MS was employed to obtain information about change in the chemical compound of coal due to oxidation. The DTG result classified the coals as belonging to sub-bituminous group. There were three reaction stage of DTG curves. Stage II determined qualities of coal as the result the oxidative behaviour. The oxidation would decrease maximum temperature and produced new volatile matter. The lower value of activation energy (Ea) of aglomeration coal caused a higher degree of oxidation and obtained more alcohol and carboxyl group. The small factor Arrhenius (A) value made slight degradation quantity volatile matter but didn?t effect on coking properties of coal. From analysis of decomposition, the coal observed could be used as a chemistry source material or secondary fuel."

"Extended Elastic Impedance method is one of the methods in reservoir characterization, which is used to identify lithology and fluids content. This method is an extension of Elastic Impedance method by changing Sin²θ in Zoeppritz equation with tan χ to get scaled reflectivity equation. χ is angle range between -90° up to 90°. By using proper angle (χ), we can calculate the reflectivity that associates with the log parameter (Gamma Ray, Porosity, Lamda-Rho and Mhu-Rho). To proceeds this scheme we need to derive gradient and intercept from AVO analysis, which is used in Zoeppritz equation to calculate reflectivity volume. The proper angle (χ), which is derived from Whitcombe equation, is 30° for Gamma Ray. While the proper angle (χ) for porosity, mhu-rho, and lambda-rho is 60°, -90° and 15° respectively.The result of mhu-rho and lamda-rho inversion in the target area contain of sandstone and oil in the time depth range of 1545 ? 1573 ms for horizon 1 and horizon 2. Based on seismic inversion, lamda-rho and mhu-rho crossplot analysis we can see that the distribution of reservoir in target area has lamda-rho value between 9050 ? 9300 m/s*g/cc or 25 ? 37 GPa*g/cc and mhu-rho value between 7500 ? 11200 m/s*g/cc or 25 ? 35 GPa*g/cc."

"ABSTRAKPerolehan TiO2 dari pasir besi melalui pelindian asam klorida (HCl) telah dilakukan. Pasir besi menjadi salah satu komoditas pertambangan yang turut memegang peranan penting dalam menggerakkan perekonomian Indonesia. TiO2 yang dapat diperoleh dari ilmenite (FeTiO3) pada pasir besi mampu memberikan nilai tambah pasir besi. Pada penelitian ini, proses diawali dengan menghaluskan pasir besi sehingga didapatkan ukuran sebesar 325 mesh yang kemudian pasir besi diseparasi menggunakan magnet NdFeB dan komposit NdFeB untuk memisahkan ilmenite dari senyawa titanomagnetite dan pengotor lainnya. Pasir yang telah diseparasi dikarakterisasi menggunakan difraksi sinar-x (XRD) dan Scanning Electron Microscope ? Energy Dispersive Spectroscopy (SEM-EDS) untuk menentukan ilmenite terbanyak.Hasil separasi mampu meningkatkan kadar ilmenite sampai 67.61% dan mengurangi senyawa pengotor seperti hematite 26.31% dan silika 4.58%. hasil separasi yang memiliki kadar ilmenite terbanyak diberikan perlakuan pelindian menggunakan asam klorida dengan konsentrasi 32%. Hasil penelitian menunjukkan bahwa proses pelindian menggunakan asam klorida dapat mengganggu struktur ilmenite menjadi TiO2 dengan tingkat kemurnian mencapai 91.46% dengan efisiensi sebesar 42.14% dan mengurangi impuritas yang signifikan.

---

ABSTRACT

Processing TiO2 from iron sand by hydrochloric acid (HCl) has been investigated. Iron sand became one of the commodities that contribute and important role in actuating the economy of Indonesia. TiO2 can be obtained from ilmenite (FeTiO3) in the iron sand so it can give the add values of iron sand. In this study, the process began from milling iron sand up to size 325 mesh and then was separated using a NdFeB magnet and composite of NdFeB to separate between titanomagnetite, ilmenite, and the impurities. Iron sand has been separated and then has been characterized by using x-ray diffraction (XRD) and Scanning Electron Microscope-Energy Dispersive Spectroscopy (SEM-EDS) to determine the highest concentration of ilmenite.

The results of separation can increase concentration of ilmenite up to 67.61% and reduce the impurity compounds such as hematite 26.31% and silica 4.58%. The results of separation which has the highest concentration of ilmenite was leached using hydrochloric acid at a concentration of 32%. The results show that the leaching process can destroying the structure of ilmenite into TiO2 purity of 91.46% with efficiency 42.14% and reducing impurities significantly."