Judul: As partial requirement fulfilment for the Doctorate Degree in plant taxonomy
Abstrak: An account of the diversity, distribution, and taxonomy of the Asteraceae in Sumatera is given, There are 133 species of74 genera in 11 tribes, New species are recoqnized in this study, Prenanthes L. (2 species), Senecio L. (1 species), and Emilia sonchifolia (L.) DC (1 variety). The tribe Heliantheae is the largest, with 28% ofthe total number ofthe genera, followed by Astereae with 15%, Inuleae 12%, Senecioneae 10%, Anthemideae, Eupatorieae and Lactuceae 8%, the' other tribes are represented by 4% or less, The most diverse genus is Blumea DC with 14 species. Other genera are only represented by 10 species or less, usually 3, or 2, or, more usually, by 1 species only. In terms ofindigenous and endemic species, Sumatera is richer than Java, There are 43 important weed species, which were introduced from tropical America, Africa, Asia and Europe. Among these Chromolaena odorata (L.) RM. King & H Rob. and Mikania micrantha Kunth are reported as the most noxious ones. Studies on 9 species of Vernonia Schreb, in Sumatera were conducted to find distinct characters to support their taxonomic delimitation. Foliar trichome types may have taxonomical value to delimit sections. However, further study on many more specimens form larger geographical areas such as Malesia is required combined with other investigations, i.e. chemotaxonomy, pollen morphology or DNA analyses to obtain a better idea for new proposals of redefinitions of the sections.
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Judul: Artabotrys (Annonacea) in East Malesia
Abstrak: Studies on the taxonomy of the genus Artabotrys R. Br. ( Annonaeceae ) in East Malesia were based on morphological characters by examining a large number of Herbarium Bogoriense (BO), Celebense (CEB), Manokwari (MAN), Departemen of Forest Lae (LAE) and living plants of Bogor Botanical Garden. There are eight species which have been known previously: A. camptopetala Diels, A. gracilis King., A. hexapetalus (L.f.) Bhandari, A. inodorus Zipp., A. macranthus Holthuis, A. speciosus Kurz., A. suaveolens Blume, A. sumatranus Miq. and A. venustus King. Four new species are proposed in this treatment : A. desmidantha Diels ex Triasti., A. longipetalus Triasti., A. palmatiflorus Triasti., and A. trichofolius Triasti.. An identification key and detailed discription are provided for taxa. Artabotrys suaveolens Blume is widely distributed. While A. camptopetala, A. desmidantha, A. longipetalus, A. inodorus, A. palmatiflorus and A. trichofolius have a limited distribution. New Guinea is the area with the highest diversity of Artabotrys species in East Malesia. A phylogenetic analysis with Cyathocalyx sumatranus as outgroup, shows three major groups. The first group is Cyatocalyx sumatranus. The second group is A. macranthus which has the closest relationship with the outgroup. The third group separated from the other group by the synapomorph characters 2 (leaf length), 3 (hook), 11 (carpel shape), 14 (number of ovule) and 15 (position of seed).
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Judul: Karakteristik lompatan hidrolik terhadap pelimpah terjunan pada saluran segi empat
Abstrak: Aliran dengan kecepatan tinggi dalam kondisi superkritis yang melintasi bangunan pelimpah, sebelum bergerak lebih jauh ke arah hilir saluran dimana bilangan Froude (F) lebih besar dari satu harus diubah menjadi aliran subkritis dimana bilangan Froudenya lebih kecil dari satu. Aliran yang meninggalkan kaki pelimpah merupakan aliran yang memiliki kandungan energi yang amat berarti sehingga dapat menimbulkan pengikisan yang besar. Pengubahan bilangan Froude dari kondisi superkritis ke subkritis dimaksudkan agar terjadi perubahan kandungan energi, sehingga aliran menjadi non erosive. Agar daya erosive aliran dapat berkurang, maka biasanya pada bagian hilir dari bangunan pelimpah dibuatkan suatu bangunan peredam energi. Erosi yang terjadi di hilir bangunan pelimpah dapat disebabkan dari keberadaan bangunan pelimpah itu sendiri, maupun bangunan peredam energi yang kurang tepat. Hal ini terutama menyangkut beberapa kejadian lompatan hidrolik yang timbul pada bangunan peredam energi tersebut.. Suatu metode yang efektif untuk menjamin bahwa lompatan hidrolik selalu terjadi pada daerah yang dilindungi, adalah dengan menggunakan bangunan peredam energi yang terdiri dari beberapa tipe dengan..dst
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