Judul: The Changes in Standing Carbon Stock and Its Implications to Land Surface Temperature: Monitoring Oil Palm Plant Growth Using Remote Sensing
Abstrak: Seperti vegetasi lainnya tanaman kelapa sawit menyerap CO2 untuk fotosintesis yang kemudian disimpan menjadi karbon organik dalam bentuk biomassa atau cadangan karbon (carbon stock). Penelitian ini bertujuan untuk menentukan cadangan karbon (Standing Carbon Stock) pertanaman kelapa sawit dan implikasinya bagi suhu permukaan dengan pertambahan umur tanaman. Data yang digunakan adalah data Landsat 7 tahun 2007, Landsat 8 tahun 2013, dan Landsat 9 tahun 2022 dengan path/row 125/61. Lokasi dalam penelitian ini adalah PT Perkebunan Nusantara VI (PTPN VI) Batang Hari, Jambi dengan tanggal akuisisi Landsat menghasilkan sebaran umur 3, 5, 8, 9, 11, 14, 18, 20, dan 23 tahun. Hasil penelitian menunjukkan adanya pengaruh umur tanaman terhadap LAI, standing carbon stock dan suhu permukaan yang mana semakin bertambah umur tanaman, maka nilai LAI dan standing carbon stock akan semakin meningkat, dan suhu permukaan akan semakin menurun. Hasil korelasi antara suhu permukaan dengan LAI dan standing carbon stock ditunjukkan dengan koefisien korelasi berturut-turut -0,95 (R2 = 0,91) dan -0,93 (R2 = 0,87) yang mana terdapat korelasi sangat kuat antar parameter. Berdasarkan hasil diatas dapat disimpulkan bahwa semakin dewasa umur tanaman kelapa sawit, maka tutupan kanopi tanaman, biomassa, dan standing carbon stock akan semakin meningkat dengan diiringi penurunan suhu permukaan perkebunan dan memberikan pengaruh penurunan suhu untuk wilayah sekitarnya., Like other vegetations, oil palm absorb CO2 for photosynthetic processes, which are then stored as organic carbon in plant biomass or denoted as standing carbon stock. This research aims to estimate the carbon stock of oil palm plantations and its implications for surface temperature with the increasing age of oil palm plantation. The data used are Landsat 7 year 2007, Landsat 8 year 2013, and Landsat 9 year 2022 path/row 125/61. The research site was in PT Perkebunan Nusantara VI (PTPN VI) Batang Hari, Jambi, with the Landsat acquisition dates resulted in plant age variation of 3, 5, 8, 9, 11, 14, 18, 20, and 23 years. The results showed the effect of plant age on LAI, carbon stocks, and surface temperature, where the increasing age of the plant resulted in increasing LAI and carbon stocks, and decreasing surface temperature. The correlation between surface temperature with LAI and carbon stock was significant, with correlation coefficients of -0.95 (R2 = 0.91) and -0.93 (R2 = 0.87). Based on these results, it can be inferred that as plants grow, becoming mature and productive, canopy cover increases, biomass, and carbon stocks increase, accompanied by a decrease in the surface temperature of the plantation and surrounding area.
Keyword: Biomass, CO2, LAI, Landsat, Plantation expansion

Judul: Perubahan Karakteristik Biofisik Perkebunan Kelapa Sawit Pada Berbagai Umur Menggunakan Data Citra Landsat
Abstrak: Oil palm (Elaeis guineensis Jacq) is the second largest agricultural product after rice and has a high potential for Indonesian exports. To increase the production, the area has to be extended to meet the demand, one of the ways is through land conversion. However, those action can lead to the changes of environmental conditions. Therefore, this study aims to identify changes of surface characteristics, ground heat flux, sensible and latent heat flux, the changes of surface and air temperature at various ages of oil palm plantation compared to forest. Estimation of changes in biophysical characteristics using remote sensing was conducted by utilizing the Landsat image data to assess the canopy densities, biophysical characteristics, and surface temperature of oil palm plantation. Albedo value decreased with increasing age, 0.11 for young oil palm, 0.08 for old oil palm. The value of fAPAR increased from 0.78 to 0.83. Sensible heat flux of young oil palm plantation was 123 Wm-2, higher than the old one; 102 Wm-2. Then, the use of energy for evaporating (latent heat flux) of young oil palm plantation was 299 Wm-2, less than the old one; 407 Wm-2. Surface temperature analyzed from image data showed there is a decreasing trend with increasing age: 32.3oC (young oil palm) to 30.8oC (old oil palm).
Keyword: Bogor Agricultural University (IPB), surface temperature, land conversion, fAPAR, energy flux, albedo

Judul: Grup dan Homomorfisma Grup pada Rubik Revenge
Abstrak: Rubik cube is a kind of puzzle game. A player must arrange rubik sides, which have been disordered, back to the position where every side has the same colour. This paper does not focus on the settlement solution, but instead on proving the existence of a group homomorphism between rubik movement group and S96 symmetric permutation group in rubik revenge. Firstly, it has been proved that rubik movement set is a group. Then, it also has been proved that the M set, which contains numeric labels of 1 until 96 in cubinos sides, is S96 symmetric permutation group.
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