Judul: Frekuensi Kunjungan Kumbang Penyerbuk Elaeidobius kamerunicus pada Bunga Betina Tanaman Kelapa Sawit di Perkebunan PTPN VIII Cimulang, Bogor
Abstrak: Elaeidobius kamerunicus had known as weevil pollinator which had important role in oil palm pollination. Application of the weevil can increase of oil production and fruit set. Visiting frequency of E. kamerunicus determine to pollination of palm oil. This study aimed to know visiting frequency of E. kamerunicus on oil palm’s female flowers age six years. Visiting frequency of E. kamerunicus was observed by fixed sample method in 4x10 minutes using three time blocks, which is in the morning (09.00-10.00 am), afternoon (01.00-02.00 pm), and evening (04.00-05.00 pm). Observations were conducted in 10 days on 10 different trees. Environment parameters which were temperature, humidity, wind speed, and light intensity were measured. A result showed that the highest weevil visitation frequent (130 weevils/10 minutes) to female flowers occurred in the morning. Visiting frequency in afternoon (28 weevils/10 minutes) and in evening (31 weevil/10 minutes) were lower than in the morning. The weevil’s visiting frequency related significantly to temperature and humidity.
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Judul: Frekuensi Kunjungan Elaeidobius kamerunicus Faust. pada Bunga Betina dan Efektivitasnya terhadap Pembentukan Buah Kelapa Sawit
Abstrak: Elaeidobius kamerunicus (Coleoptera: Curculionidae) is the most effective pollinator of oil palm. This research aimed to study visiting frequency of E. kamerunicus on female flowers and its effectiveness to oil palm’s fruit set. Fix sample method was used to observe visiting frequency of E. kamerunicus. Observations were conducted in 10 minutes in the morning (09:00-10:00 am), afternoon (13:00-14:00 pm), and evening (16:00-17:00 pm). The environmental parameters were measured to know its effect to visiting frequency the weevil. The weevil mostly visited the flower in the morning (109 weevils/10 minutes), decreased at afternoon (26 weevils/10 minutes), and in the evening (13 weevils/10 minutes). The average visiting frequency of weevil to the female flowers was 50 individuals/10 minutes. Pollen load of the male weevil was 1440 pollen, while the female loaded about 635 pollen. The pollen viability on male and female body of the weevil were 8.65% and 7.90%, respectively. The average of oil palm’s fruit set in Sukamaju Plantation was 77.87%. The visiting frequency of weevil to the female flowers was positively related to the oil palm’s fruit set.
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Judul: Effects of NaMnN2 Material Phase Differences on the Properties and Performance of Sodium Ion Battery Cathodes
Abstrak: Kemajuan teknologi menyebabkan kebutuhan akan baterai isi ulang meningkat. Namun baterai ion litium sebagai baterai yang umum digunakan mengalami kenaikan harga yang tinggi karena kelangkaan litium di alam. Baterai ion natrium sebagai baterai alternatif dari baterai ion litium belum menemukan kandidat material katoda yang tepat. NaMnN2 dari keluarga Layered N-based TMDs-like diharapkan dapat menjadi material katoda baterai ion natrium yang murah dan baik. Density Functional Theory digunakan dalam penelitian ini untuk membuktikan pengaruh fasa terhadap sifat elektronik dan performansi material katoda NaMnN2, sehingga dapat diperoleh fasa terbaik bagi keluarga Layered N-based TMDs-like sebagai katoda baterai ion natrium. Hasil penelitian menunjukan bahwa secara teoretis NaMnN2 berpotensi sebagai katoda baterai ion natrium yang memiliki performansi baik. Selain itu, NaMnN2 fasa 2H memiliki keunggulan pada kestabilan siklus, memiliki konduktivitas yang sangat baik, serta mengalami difusivitas ion Na yang baik dengan energi penghalang sebesar 0,41 eV. Material NaMnN2 fasa 1T unggul dalam tegangan yang lebih tinggi, mencapai 3,93 V, serta memiliki rapat energi yang besarnya mencapai 995,22 Wh/kg., Technological advancements have caused the need for rechargeable batteries to increase. However, lithium ion battery as a commonly used battery has experienced a high price increase due to the scarcity of lithium in nature. Sodium ion battery as an alternative battery to lithium ion battery has not found the right cathode material candidate. NaMnN2 from the Layered N-based TMDs-like family is expected to be a cheap and good sodium ion battery cathode material. Density Functional Theory is used in this study to prove the effect of phase on the electronic properties and performance of NaMnN2 cathode material, so that the best phase can be obtained for the Layered N-based TMDs-like family as a sodium ion battery cathode. The results showed that theoretically NaMnN2 has the potential as a cathode of sodium ion battery which has good performance. In addition, 2H-phase of NaMnN2 has advantages in cycle stability, has excellent conductivity, and experiences good sodium ion diffusivity with a barrier energy of 0,41 eV. The 1T phase NaMnN2 material excels in higher voltages, reaching 3,93 V, and has an energy density of up to 995,22 Wh/kg.
Keyword: cathode, DFT, phase, Quantum Espresso, SIB