Judul: Keanekaragaman spesies dan kunci identifikasi kutukebul (Hemiptera: Aleyrodidae) pada tanaman pertanian di Jawa Barat
Abstrak: Whiteflies are one of the most important insect group of pests in agricultural crops which can cause direct and indirect damages to plants, i.e. disturb photosynthesis and plant aesthetics, and transmit plant viruses. Whiteflies have been reported in Indonesia since 1900’s. There are 37 whiteflies species that have been recorded in Indonesia, but it is believed that many more are unidentified. The aims of this research was to identify the whiteflies species in agricultural crops and study their diversity at different altitudes. Whiteflies were collected at five areas in West Java: Bogor, Cianjur, Sukabumi, Bandung, and Garut. The identification of whiteflies were using fourth instar nymph or known as pupa. Slide preparation followed Watson’s protocol that has been modified. Morphological characters for such species were recorded for identification. Identification key was constructed in the dichotomous and digital forms using Lucid Phoenix Key program. Diversity of whiteflies was analysed using Shannons’s (H’), Simpson’s (D) and Sorenson’s (C) diversity index. Whitefly natural enemies that were found in the field or parasitized whiteflies were identified. There were 38 whiteflies species found and 10 were still unidentified. About 89.5% whiteflies found were the member of subfamily Aleyrodinae. Whiteflies were more commonly found in the plants with complex architecture (fruit trees) than the plants with simple architecture (vegetables, ornamental plants, etc). Plant with complex architecture can provide more space and food for organism to live. Aleurodicus dispersus and Aleurodicus dugesii are cosmopolitan species that can be found in various types of plants and altitudes. Bemisia tabaci was commonly found in lower altitude, whereas Trialeurodes vaporariorum was mainly found in higher altitude. Both species are become important pests in vegetable crops and transmit plant diseases. The highest whitefly species richness and diversity was found in lowland (0-500 m above sea level (asl)) (H’=2.14; 1- D=5.53). Similarity analysis (C) showed that number of whitefly species found at lowland was 64% similar to midland (501-1000 m asl). The natural enemies that commonly found were coccinellid beetle, aphelinid, and encyrtid wasp.
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Judul: Analisis keragaman dan stabilitas genetik temulawak (Curcuma xanthorriza Roxb.) Indonesia
Abstrak: Study on The Identification of Parasitoids and Predators of White Fly on Mulberry Plant was conducted at Bogor, Sukabumi and Tasikmalaya as well as Pati and Candiroto on sericulture developing centers of West Java and Central Java, respectively. The main objectives of the study were to confirm the species of white fly and also to confirm whether there is any parasitoid as well as predator attacking the pest in all the study sites. To achieve the targeted output of the study the following methods were conducted. The collected whiteflies from all study sites were send to entomological laboratory of Bogor Agriculture University, while the collected parasitoids and predator were send to National Entomological Museum at Bogor. To proof an insect to be parasitoid of the whitefly, in captive method was practiced. While to proof an insect to be predator of the fly, the bait method was practiced. The result of the study showed that white attacking mulberry plant at study sites is Trialeurodes vaporarium Martin. There are four species parasitoids namely Ceraphronid, Scelionid, Eucoilid and Eulophid and four species of predacious Coccinelid namely Serangium spp and Micraspis sp.
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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