Judul: Change in Determaining Factor of Oil Palm Evapotranspiration  to Variation of Consecutive Dry Days and Rainfall Intensity
Abstrak: Penelitian ini dilakukan untuk mengetahui perubahan faktor penentu evapotranspirasi kelapa sawit berupa radiasi netto, kelembapan tanah, kecepatan angin dan defisit tekanan uap karena adanya variasi intensitas curah hujan dan periodeo kering. Analisis ini dilakukan dengan dua tahap yakni, pendugaan evapotranspirasi, dan analisis regresi. Pendugaan evapotranspirasi dilakukan dengan metode aerodinamik, sedangkan untuk analisis regresi dilakuka dengan regresi linier sederhana. Hasil penelitian menunjukkan bahwa intensitas curah hujan memiliki pengaruh negarif terhadap evapotranspirasi. Hal ini dapat dilihat dari nilai evapotranspirasi yang maksimal ketika hari tidak hujan, dan menurun ketika hari hujan meningkat, serta nilai evapotranspirasi bulan kering yang menujukkan nilai lebih besar daripada bulan basah. Waktu puncak evapotranspirasi yang terjadi pada bulan kering memiliki gap selama satu jam dengan puncak evapotranspirasi yang terjadi pada bulan basah. Secara keseluruhan perubahan pada intensitas curah hujan dan periode kering mempengaruhi perubahan pada faktor penentu evapotranspirasi. Hal ini dapat dilihat dari pengaruh radiasi netto terhadap evapotranspirasi yang menurun seiring dengan bertambahnya durasi periode kering, kecepatan angin yang hanya berpengaruh pada periode kering kurang dari seminggu, serta kecilnya pengaruh dari kelembapan tanah terhadap evapotranspirasi ketika terjadi curah hujan dengan intensiats tinggi. Faktor penentu evapotranspirasi yang tidak mengalami perubahan segnifikan adalah defisit tekanan uap. Faktor cuaca ini memiliki pengaruh paling besar terhadap evapotranspirasi pada tiap keadaan, dengan nilai R2 diatas 0.9., This research was conduct to study changes in the determain of oil palm evapotranspiration that are net radiation, soil moisture, wind speed and vapor pressure deficit due to variations in rainfall intensity and dry period. This analysis was carried out in two stages, estimation of evapotranspiration, and regression analysis. Estimation of evapotranspiration was carried out by aerodynamic methods, while regression analysis was performed by simple linear regression. The results showed that the intensity of rainfall had a negative effect on evapotranspiration. This can be seen from the maximum evapotranspiration value that occurs when it’s no rain and decreases when it rains, and the dry season evapotranspiration value which shows a greater value than the wet season. The peak time of evapotranspiration that occurs in the dry season has a gap of one hour with the peak of evapotranspiration that occurs in the wet season. Overall, changes in rainfall intensity and dry period affect the changes in determain of oil evapotranspiration. This can be seen from the effect of net radiation on evapotranspiration which decreases with increasing dry period duration, wind speed which only affects dry periods of less than a week, and the small effect of soil moisture on evapotranspiration when rainfall occurs with high intensity. The determinant of evapotranspiration that did not change significantly was the vapor pressure deficit. This meteorogical factor has the greatest influence on evapotranspiration in each situation, with an R2 value above 0.9.
Keyword: Aerodinamic, Evapotranspitarion, Rainfall, Oil palm

Judul: Comparison of Evapotranspiration Dynamics between Oil Palm Plantation and Secondary Forest in Jambi Province
Abstrak: Kelapa sawit merupakan salah satu komoditas perkebunan utama Indonesia dan berperan penting dalam perekonomian nasional. Karena memiliki nilai ekonomi yang sangat tinggi, perkebunan kelapa sawit telah berkembang pesat di seluruh Indonesia. Namun, konversi lahan alam menjadi perkebunan kelapa sawit telah menimbulkan sentimen negatif dari dunia internasional terhadap Indonesia, kelapa sawit dianggap boros air dan menjadi penyebab kekeringan. Penelitian ini bertujuan untuk menganalisis dinamika dan laju evapotranspirasi pada perkebunan kelapa sawit dengan menggunakan beberapa metode sebagai pembanding. Metode yang digunakan dalam penelitian ini antara lain metode Aerodinamik dan metode Penman-Monteith untuk estimasi, serta metode Eddy Covariance sebagai referensi. Laju evapotranspirasi yang diperoleh kemudian dibandingkan dengan kawasan hutan untuk melihat perbedaan laju evapotranspirasi antara ekosistem buatan, PTPN VI Jambi, dan ekosistem alami, Hutan Harapan Jambi. Dinamika diurnal laju evapotranspirasi di perkebunan kelapa sawit dan hutan menunjukkan pola yang sama, yaitu meningkat pada siang hari dan menurun pada malam hari. Laju evapotranspirasi di Hutan Harapan memiliki nilai lebih tinggi, yaitu 6,1 mm/hari dibandingkan dengan perkebunan kelapa sawit yang hanya 4,42 mm/hari. Hasil ini dapat membantah sentimen negatif terhadap kelapa sawit, terutama terkait penggunaan air., Palm oil is one of Indonesia's primary plantation commodities and plays a crucial role in the national economy. It has a very high economic value, so palm oil plantations have expanded widely across Indonesia. However, converting natural land into palm oil plantations has led to negative international sentiment towards Indonesia, palm oil is seen as “water greedy” and a cause of drought. This study aims to analyze the dynamics and rate of evapotranspiration in palm oil plantations using several methods for comparison. The methods used in this research include the Aerodynamic method and the Penman-Monteith method for estimation, and the Eddy Covariance method as a reference. The evapotranspiration rates obtained are then compared with forest areas to observe the differences in evapotranspiration rates between the man-made ecosystem, PTPN VI Batanghari, Jambi, and the natural ecosystem, Hutan Harapan, Jambi. The diurnal dynamics of evapotranspiration rates in both the palm oil plantations and the forest show similar patterns, increasing during the day and decreasing at night. The evapotranspiration rate in Hutan Harapan is higher at 6.1 mm/day compared to the palm oil plantation at 4.42 mm/day. These results counter the negative sentiment towards palm oil, particularly regarding its water usage.
Keyword: penman-monteith, forest, evapotranspiration, oil palm, aerodynamics

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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