Judul: Serangga Pengunjung Bunga Betina dan Polen yang Terbawa Kumbang Elaeidobius kamerunicus pada Kelapa Sawit
Abstrak: Receptive female flowers of oil palm emit volatile compounds that attract insect to visit the flowers. This research aimed to study female flowers visiting insect and pollen loaded by weevil E. kamerunicus of oil palm. Observations of insects were done by using fix sample method during 10 minutes on receptive female flowers. The weather condition which were measured during observation of insects, i.e. temperature, humidity, light intensity, and wind speed. Insect samples were collected for identification and weevil E. kamerunicus were taken for pollen load measurement. Result showed that the female flowers visiting insect of oil palm were E. kamerunicus (Coleoptera), Chelisoches sp., Forficula sp. (Dermaptera), Scaptodrosophila sp. (Diptera), Camponotus sp., Oecophylla sp., Plagiolepis sp., Polyrhachis sp., Leptanilla sp., Odontoponera sp. (Hymenoptera), and Thrips hawaiiensis (Thysanoptera). Weevil E. kamerunicus was dominant visiting insect. The diversity and evenness of visiting insect on oil palm was considerably low (H ’=0,85; E=0,35). Pollen loaded by male weevil E. kamerunicus (1604 pollens) was higher than that of the female (719 pollens).
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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: 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