Judul: Identifikasi dan penentuan faktor-faktor utama penyebab tanah longsor di Kabupaten Garut, Jawa Barat
Abstrak: According to the data of mass movement disaster in Indonesia from 1990 to 2002, West Java Province (including Banten Province) frequentcy experienced landslide disaster. The map of mass movement of Garut District (Peta Gerakan Tanah Kabupaten Garut) made by Directorate of Vulcanology and Geological Disaster Mitigation (Direktorat Vulkanologi dan Mitigasi Bencana Geologi – DVMG), showed that there were several areas in Garut District classified in Susceptible Zones of high mass movement such as Banjarwangi District, Singajaya and Peundeuy. This study aims to 1) identify and analyze the characteristics of landslide in Garut District particularly in 3 municipals (Banjarwangi, Singajaya, and Peundeuy), 2) develop a model of relationsh ip between various causes of landslide and its conditions. In the preliminary stage of the study, literatures study on various factors of landslide were conducted and it is established in check list form as the field manual. The factors of landslide were then identified and analyzed. Based on analyzed data Principal Component Analysis (PCA) was conducted as well as cluster analysis and regression analysis to develop model of the landslide. Based on the observation, there were 32 spots of landslides occurred in the study area. There were 2 (two) characteristics of landslide found : 1) earth flow (30 cases or 94%), and 2) subsidence (2 cases or 60%). The high landslide as found in rice field area (25 spots) and followed by mixture garden/agroforestry (4 spots), 2 spots in housing area and 1 spot in the annual crops planted area. Analysis of PCA resulted 5 cluster with >40% similarity index. The multiple regression has generated an equation as followed: Y = 1.55 + 0.00186 v1 - 0.061 v3 + 0.038 v4 + 0.0216 v9 - 0.100 v13 where; Y : conditions of landslide zones, v1: soil thickness, v3: erosion conditions, v4: soil texture, v9: slope, and v13 : landuse (rice field).
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Judul: Pola Sebaran Titik Longsor dan Keterkaitannya dengan Faktor-Faktor Biogeofisik Lahan (Studi Kasus Kabupaten Garut Jawa Barat)
Abstrak: Bencana longsor merupakan fenomena alam yang sering terjadi di Indonesia. Longsor adalah proses perpindahan material pembentuk lereng, berupa batuan, bahan rombakan, tanah, atau material campuran yang bergerak menuju ke lereng bawah akibat adanya gaya gravitasi. Di Jawa, Kabupaten Garut merupakan salah satu kabupaten yang sering mengalami bencana longsor, oleh karena itu dipilih sebagai daerah penelitian. Tujuan dari penelitian ini adalah (1) memetakan titik longsor di Kabupaten Garut, (2) menganalisis penyebab longsor di Kabupaten Garut, (3) memetakan daerah bahaya longsor di Kabupaten Garut, dan (4) memetakan daerah resiko longsor di Kabupaten Garut. Metode yang digunakan untuk mencapai tujuan penelitian ini adalah kerja lapangan untuk menemukan dan memetakan titik-titik longsor di lapangan, kemudian hasilnya dibandingkan dengan persebaran spasial dari masing-masing parameter penentu longsor (lereng, elevasi, formasi geologi, jenis tanah, curah hujan, penggunaan lahan), dan melalui analisis spasial tumpang tindih sistem informasi geografis (SIG) dilakukan analisis untuk mengetahui penyebab longsor yang utama di daerah penelitian. Analisis bahaya dan resiko longsor dilakukan dengan metode skoring dengan formula penjumlahan dari masing-masing skor parameter untuk mengetahui kelas bahaya dan resiko. Hasil yang diperoleh dalam penelitian ini adalah ditemukan sebanyak 43 titik longsor yang tersebar di daerah penelitian, terutama banyak terdapat di wilayah Selatan Kabupaten Garut yang mempunyai topografi berbukit dan bergunung. Dalam hal ini kemiringan lereng dan curah hujan merupakan parameter yang paling utama sebagai penyebab terjadinya longsor di daerah penelitian. Berkaitan dengan hal itu, maka wilayah yang mempunyai tingkat bahaya longsor tinggi banyak tersebar di wilayah Selatan Kabupaten Garut. Persentase kelas bahaya longsor yang diperoleh adalah 0,1 % dari luas total daerah penelitian mempunyai kelas bahaya sangat tinggi, 33,5 % kelas bahaya tinggi, 42,1 % kelas bahaya sedang, 19 % kelas bahaya rendah, dan 5,3 % kelas bahaya sangat rendah. Adapun untuk penilaian resiko longsor didasarkan pada besarnya tingkat bahaya dan nilai properti yang terancam. Hasil dari analisis resiko yang didapatkan 1,8 % dari luas total daerah penelitian mempunyai tingkat resiko tinggi, 66,5 % kelas resiko sedang, 31,2 % kelas resiko rendah, dan 0,5 % kelas resiko sangat rendah. Besarnya tingkat resiko yang sedang ini disebabkan oleh rendahnya nilai properti di wilayah penelitian, atau dengan kata lain longsor banyak terjadi di daerah perdesaan di wilayah Selatan Kabupaten Garut..
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Judul: Hybrid solar cells of ZnO nanoparticles/chlorophyll was modified metal ions (Zn2+ and Cu2+ )
Abstrak: Zinc Oxide (ZnO) is a n-type semiconductor with a wide the energy band (Band Gap) is 3.37 eV at room temperature and 3.34 eV at low temperature with a large exiton binding energy is 60 meV. ZnO has been synthesized by hydrothermal method, resulting in a decrease in particle size over the duration of the hydrothermal changes. Crystallographic structure of ZnO were characterized using XRD, has shown the characteristic pattern of a hexagonal wurtzite structure, the crystallite size increases to changes in particle size. Changes in particle size has also led to a change in the absorption peak of ZnO as has been demonstrated posted under test using the optical properties of UV-Vis spectrophotometer. Changes of this uptake has also led to changes in the energy band gap, which increases its band gap energy of the particle size. In electronic applications, especially in solar cells. Chlorophyll is considered less effective, because of their very nature are easily degraded as a result of several reactions which are acid, lighting and temperature. The results of the stability test using a halogen lamp 34 W/m2 for 5 hours, that the substitution of chlorophyll with metal ions Zn2+ and Cu2+ has been shown to form more stable than natural chlorophyll. The characterization of the optical properties, the combination of ZnO / chlorophyll in the form of hybrid films has led to a shift in the absorption region of ZnO becomes more widely from the UV to Visible. ZnO/chlorophyll has absorption range of 350-515 nm, ZnO / Zn-feofitin 332-401 nm and 332-632 nm for Cu-feofitin. The combination of ZnO/chlorophyll and CuSCN as a solid electrolite in hybrid solar cell, a modified chlorophyll with metal ions Zn2+ and Cu2+ has been shown to form a more stable I-V curve. It is characterized by its fill factor value greater than natural chlorophyll. Nevertheless, solar cells with natural chlorophyll has been able to produce higher efficiency values of chlorophyll were substituted.
Keyword: Hydrothermal, ZnO/Chlorophyll modified, Hybrid Solar Cell