Judul: Karakteristik Kekasapan Permukaan dan Pengaruhnya terhadap Transfer Turbulen Momentum dan Bahang (Studi Kasus : Wilayah Pertanian Situ Gede, Darmaga, Bogor)
Abstrak: Wind influences growth, development, and crops production through exchange of heat, water vapor, CO2, and momentum between the plant and the atmosphere. The purpose of this research is to determine wind parameters, i.e. roughness parameters (zero-plane displacement (d), roughness length (z0), and friction velocity (u*)) and coefficient of momentum transfer (Km) in rainy and dry season at agriculture Situ Gede fields, and used them to calculate momentum transfer () and heat transfer (QH). Roughness parameters and Km varied with wind speed. In general, the season influences the values. Roughness parameters in rainy season tend to be higher than in dry season. The value of z0 range from 0.00-0.51 m, d 0.38-4.00 m, and u* 0.008-0.357 m s-1. Km changes with hight and season. The value of  range from 0.0029-0.0556 N m-2 in rainy season and 0.0033-0.0368 N m-2 in dry season. The value of QH range from -4.1879-2.0393 MJ m-2hari-1 in rainy season and -4.0337-2.4165 MJ m-2 hari-1 in dry season. It can be concluded that momentum transfer in rainy season would be more effective than in dry season, it is expected that physiological processes of plants can be held optimum, and also development and growth of plants would be better.
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Judul: The dynamics of surface boundary layer characteristics above oil palm plantation
Abstrak: Penelitian yang dilakukan di dua lokasi perkebunan sawit, yaitu di Desa Pompa Air, Jambi (umur 2 tahun) dan di PT. Perkebunan Nusantara VIII, Cimulang, Jawa Barat (umur 8-10 tahun) menunjukkan bahwa karakteristik kekasapan (perpindahan bidang nol (𝑑��), kecepatan kasap (𝑢��∗), dan panjang kekasapan (𝑧��0)) meningkat dengan bertambahnya umur tanaman. Parameter kekasapan ini menentukan dinamika profil-vertikal kecepatan angin, intensitas turbulensi, energi kinetik turbulensi (TKE), dan juga transfer momentum serta bahang (terasa dan uap air). Berdasarkan hasil yang diperoleh pada kedua lokasi perkebunan, kecepatan angin di dekat permukaan akan mengalami disturbansi dan menurun secara logaritmik karena gesekan dengan permukaan yang berkorelasi positif dengan koefisien drag (𝐶��𝐷��). Nilai 𝐶��𝐷�� sebanding dengan kuadrat rasio antara kecepatan tangensial parsel udara karena turbulensi mekanik dengan kecepatan angin rata-rata pada ketinggian tertentu. Nilai koefisien drag pada kondisi netral 𝐶��𝐷�� cenderung menurun terhadap pertambahan kecepatan angin. Pada kondisi atmosfer tidak stabil, proses pemanasan permukaan oleh radiasi matahari mendorong terbentuknya pengangkatan massa udara ke atas (buoyancy) yang mencapai puncak pada tengah hari (12.00-14.00 WIB). Semua mekanisme ini menyebabkan gerakan acak aliran massa udara dan mengubah energi kinetik serta potensial aliran pada suatu ketinggian menjadi TKE. Analisis menunjukkan TKE memiliki korelasi yang tinggi dengan transfer bahang terasa dan uap air. Hal ini menunjukkan bahwa turbulensi lebih efektif dalam proses pencampuran dibanding melalui proses difusi molekular., The research conducted in two separated oil palm plantation sites, i.e. in Pompa Air Village, Jambi (2 years old of oil palm) and in PT. Perkebunan Nusantara VIII, Cimulang, West Java (8-10 years old of oil palm) showed that the roughness parameters including zero-plane displacement (𝑑�), friction velocity (𝑢�∗), and roughness length (𝑧�0) increase with the rise of the age of plants. These parameters play a crucial role in affecting the dynamics of wind vertical-profile, turbulence intensity, turbulence kinetic energy (TKE), as well as momentum and heat (sensible and latent) transport mechanisms. Based on the results, above the plant canopies of both of plantation sites, the wind speed will be disturbed by and logarithmically decreased downward to just above the roughness elements by the surface shear stress which has postitive correlation with the drag coefficient (𝐶�𝐷�). Value of 𝐶�𝐷� is equivalent to square of ratio between the tangential velocity of air flow generated by mechanical turbulence and wind speed at certain height. Above both of plantation sites in neutral atmospheric condition 𝐶�𝐷� tended to decrease with the increase of wind speed. In addition, in unstable atmospheric condition, surface heating process by short wave radiation generates buoyancy reaching its peak at mid-day (12 am - 2 pm). All of these mechanisms cause chaotic air flow and convert kinetic and potential energy of stratified mean flow into TKE. Based on result, TKE had high correlation with sensible heat flux and latent heat flux as well. It showed that turbulence has more efficient mixing mechanism than molecular diffussion process. Keywords: roughness parameters, zero-plane displacement, friction velocity, roughness length, turbulence, TKE, drag coefficient, momentum flux, heat flux
Keyword: kekasapan permukaan, perpindahan bidang nol, kecepatan kasap, panjang kekasapan, turbulensi, TKE, koefisien drag, transfer momentum, transfer bahang

Judul: Posisi Filogenetik Kura-Kura Carettochelys Insculpta  (Reptillia: Testudinata)
Abstrak: Carettochelys insculpta is an endemic freshwater turtle of southern Papua and northern Australia. Phylogenetic position of this turtle is remain unresolved until now. Most of the research conducted show close relationships of C. insculpta and members of Trionychidae family. However, some of the research show distance between C. insculpta and members of Trionychidae family. This research is conducted to analyze phylogenetic relationship between C. insculpta and other members of Testudinata using 12S rRNA, 16S rRNA, and both gene as markers. DNA samples were obtained from three different organisms of C. insculpta. Two species used as outgroups were Alligator mississippiensis and Iguana iguana. Phylogenetic analysis was carried out using Neighbor-Joining method with Felsenstein 1981 (F81) modeltest. A polytomy tree of Testudinata was produced by using 12S rRNA gene. However, analysis using 16S rRNA and both genes as markers confirmed that C. insculpta was located between the Chelonidae and the Trionychidae family.
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