Judul: Komunitas Serangga Indigenous pada Bunga Jantan Kelapa Sawit (Elaeis guineensis Jacq.) di Kebun PTPN VIII Cimulang Bogor.
Abstrak: Oil palm is the biggest source of natural oil in the world. Oil palm is monoecious plant, but the male and female flower of the plant located at a different cluster. This study addressed to study indigenous insect community on male flower at oil palm. The insect were observed by fixed sample method on May, June 2011, January, November, and December 2012. Relationship between environment factors and insect community were analyzed by Pearson’s correlation with Sigmaplot software version 10.0. From the observation we found 5 order and 10 genera, such as Apis, Odontomachus, Camponotus, Anoplolepis, Braconid, Scaptodrosophila, Curculionid, and Dermaptera (sp1, 2, and 3). Bee, Apis cerana visited male flower of oil palm and the species role in pollination. The other, we found predatory insects, such as, Odontomachus, Anoplolepis, and Dermaptera. Result showed that the most dominant insect was Scaptodrosophila sp. The insect population significantly affected by environmental temperature.
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Judul: Komunitas Semut Pada Bunga Jantan Kelapa Sawit di Kebun Cimulang PTPN VIII Bogor, Jawa Barat.
Abstrak: Ants are the most successful eusocial insect in the world, since highly adapted to the environment. The objective of this research was to study ants community on male flower of oil palm. Observation of ants were done by using fix sample method during 10 minutes in 3 time periods, which is in the morning (08. 00 - 10.00 am), noon (10. 00 - 12. 00 am), and evening (13. 00 - 15. 00 pm). The observations of ants were conducted during four days in each month, i.e. April, May, June 2012. During observation we collected ant samples to identification process. Weather elements, i.e. air temperature, humidity, and light intensity were measured. Results showed that ant community on male flower of oil palm consist of nine genera belong to four subfamilies, i.e. Leptanilla (subfamily Leptanillinae), Oecophylla, Polyrhachis, Plagiolepis, Camponotus (subfamily Formicinae), Odontoponera, Platyhyrea, Pachycondyla (subfamily Ponerinae), and Myrmica (subfamily Myrmicinae). Leptanilla was a dominant ant species on male flower of oils palm. Diversity of ant community on male flower of oils palm was lower (H ’=0,99) and medium evennes (E=0,45).
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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