Measurement of entropy production rate in compressible turbulence

The rate of change of entropy $\dot S$ is measured for a system of particles floating on the surface of a fluid maintained in a turbulent steady state. The resulting coagulation of the floaters allows one to relate $\dot S$ to the velocity divergence and to the Lyapunov exponents characterizing the behavior of this system. The quantities measured from experiments and simulations are found to agree well with the theoretical predictions.Comment: 7 Pages, 4 figures, 1 tabl

Energy flux fluctuations in a finite volume of turbulent flow

The flux of turbulent kinetic energy from large to small spatial scales is measured in a small domain B of varying size R. The probability distribution function of the flux is obtained using a time-local version of Kolmogorov's four-fifths law. The measurements, made at a moderate Reynolds number, show frequent events where the flux is backscattered from small to large scales, their frequency increasing as R is decreased. The observations are corroborated by a numerical simulation based on the motion of many particles and on an explicit form of the eddy damping.Comment: 10 Pages, 5 figures, 1 tabl

Evaluasi Berbagai Dosis Nitrogen Untuk Teknik Produksi Tanaman Cabai Yang Menggunakan Mulsa

Kebanyakan petani tetap menggunakan dosis pupuk nitrogen sesuai rekomendasi dalam produksi cabai dengan menggunakan mulsa plastik hitam perak. Hasil penelitian sebelumnya mengindikasikan bahwa penggunaan mulsa mampu mengurangi pencucian nitrogen. Dengan demikian, perlu upaya untuk mencari seberapa banyak penurunan nitrogen yang dapat diberikan kepada cabai yang diproduksi dengan menggunakan mulsa. Penelitian dilaksanakan di Kota Bengkulu dari Maret sampai September 2004 menggunakan rancangan acak kelompok lengkap dengan dua faktor dan tiga ulangan. Faktor pertama adalah jenis mulsa yang digunakan ; mulsa plastik hitam perak, mulsa jerami padi dan tanpa mulsa. Faktor kedua adalah dosis nitrogen ; 115 kg/ha (dosis rekomendasi), 103,5 kg/ha, 92 kg/ha, dan 80,5 kg/ha. Hasil penelitian menunjukkan bahwa tidak terdapat interaksi antara jenis mulsa dengan dosis nitrogen dalam meningkatkan atau menurunkan semua variabel yang diamati. Cabai yang ditanam dengan menggunakan mulsa jerami memiliki jumlah cabang dikotom yang lebih tinggi dibanding tanaman yang ditanam tanpa mulsa, tetapi tidak berbeda dengan cabai yang ditanam dengan mulsa plastik hitam perak. Meskipun tidak ada interaksi antara jenis mulsa yang digunakan dengan dosis nitrogen dalam meningkatkan atau menurunkan variabel yang diamati, penggunaan 80,5 kg/ha nitrogen (30 persen lebih rendah dari dosis rekomendasi) meningkatkan jumlah dan bobot buah tanaman cabai

Masa Inkubasi Penyakit Karat Daun Dan Tingkat Kerusakan Pada Bibit Perupuk (Lophopetalum Multinervium) Di Persemaian PT. Inhutani II Mandor

This study aimed to determine the level of damage to seedlings Perupuk caused by leaf rust disease and know the incubation time is needed leaf rust pathogen that infects seedlings Perupuk and study the development of leaf rust disease symptoms on seedlings Perupuk. Observation of the stricken plant was conducted using descriptive, of direct observation in the field and conducted an assessment of the extent of damage caused by the attack while the incubation time in the laboratory. The results showed that the leaf rust disease incubation time attacking seedlings Perupuk (Lophopetalum multinevium) were 19 hours and the percentage of plants damaged by leaf rust disease were 71.22%. This was high and affects the quality of Perupuk growth at the sites. While the average level of crop damage due to attack Perupuk leaf rust disease on study sites were classified in the category that was equal to 44.26%. Keyword: Perupuk, attack rate, decay rate, incubation time

Where surface physics and fluid dynamics meet: rupture of an amphiphile layer by fluid flow

We investigate the fluctuating pattern created by a jet of fluid impingent upon an amphiphile-covered surface. This microscopically thin layer is initially covered with 50 $\mu$m floating particles so that the layer can be visualized. A vertical jet of water located below the surface and directed upward drives a hole in this layer. The hole is particle-free and is surrounded by the particle-laden amphiphile region. The jet ruptures the amphiphile layer creating a particle-free region that is surrounded by the particle-covered surface. The aim of the experiment is to understand the (fluctuating) shape of the ramified interface between the particle-laden and particle-free regions.Comment: published in Journal of Chemical Physic

Analisis Kualitas Dem Dengan Membandingkan Metode Orthorektifikasi Memakai Citra Resolusi Tinggi (Studi Kasus: Kecamatan Limbangan, Kabupaten Kendal, Jawa Tengah)

Satellite image of the currently used for large scale map.. To create a map with satellite imagery should be to data requires like data Digital Elevation Model (DEM) and Ground Control Point (GCP) data. The use of DEM made for eliminate the effects of relief displacement in areas that have a high elevation. However, the use of different DEM data will determine the outcome otho image. This study aimed to evaluate the influence of the quality of the DEM against the accuracy of horizontal (X and Y coordinates) ortho image by comparing the results of two mathematical models orthorectification and 2 different DEM data characteristics.DEM data are used that have two TerraSAR-X DEM and DEM SRTM 30m. The use of high-resolution DEM expected to improve the quality of ortho image. Data GCP at the scene of photo seven points plus 10 check point (ICP). In this study used a mathematical model that models orthorectification Toutin and Model RPC (Rational Polynomial coeficient). Model selection is performed for each model can be included information DEM and GCP. To analyze the effect of using the DEM data information check point. The results showed that the use of models Toutin with SRTM DEM have a smaller RMSE different DEM 0.01 meters compared with TerraSAR-X. And the other model RPC smallest RMSE values using TerraSAR-X DEM with the differences 0,028 meters then use SRTM. This shows that the use DEM to eliminate the shift relief less influence on the accuracy of the image upright. Results ortho image on each model has an accuracy of less than 2.5 meter. Key words : Orthorektifikasi, TerraSAR-X, WorldView2A, RMSE, Standard Deviation. *) Penulis Penanggung Jawa

Verifikasi Koordinat Titik Patok Batas Wilayah dengan Ntrip-cors (Studi Kasus : Batas Kota Semarang dengan Kabupaten Kendal)

Indonesia is an archipelago with total of 34 provinces, the border is an absolute thing that must be considered in Geospatial information. Boundaries between regions are presented in the list of coordinates that have been set up and included in the Ministry of Internal Affairs and the physical form of the border is presented by pillars. But in fact the pillars of the boundary area may not be placed right on the actual coordinates from the border, causing the change in the value of the coordinates, so it\u27s need a verification.Related to these problems, then at this research the pillars of boundary area are measured using GNSS CORS (Global Navigation Sattelite system Continously Operating Reference Stations) systems with RTK-NTRIP (Real Time Kinematik- Networked Transport of RTCM via Internet Protocol) method, that is GPS measurement method that gets corrections by Real Time with stateless protocol based on HTTP protocol which is their use has limited in measurement and plot details of the situation .The results indicate that there is a difference in the value of the coordinate between the measurement of the pillars with RTK - NTRIP method to the boundary areas that listed in the Regulation with maximum value 74.5m, minimum value 1.8m, standar deviation 17.07m, because the value of the coordinates that listed in the Regulation refers to the administrative area boundaries, is not the coordinate value that refers to the field

Penentuan Area Luapan Kali Babon Akibat Kenaikan Debit Air Berbasis Sistem Informasi Geografis

Semarang city is one of the regions in Indonesia are vulnerable to flooding. This condition is getting worse by the land subsidence during the year to reach 0,7 – 11,2 cm / year. Water flooding which inundate along the Kali Babon Watershed have flooded the area around the river. Starting from Bendung Pucang Gading, Kali Babon Watershed experiencing siltation due to the slope of a gentle stream them more prone to sedimentation, thereby reducing the drainage capacity.This research uses open source software Hec RAS version 4.1.0. to analyze the profile of the river water level and produce flood inundation area with a certain depth of flood discharge plans with 5, 10 and 25 years.Results obtained from the distribution of the data processing occurs on the widest flood area Sriwulan village, district. Sayung, Kab. Demak approximately 247,965 hectares and a depth ranging from 0,00154448 to 4,5808 meters at discharge of 5-years plan; 249,598 hectares and a depth ranging from 0,00154781 to 10,1064 meters at discharge of 10-years plan , 482,180 hectares with depths ranging from 0,000581622 to 12,6956 meters at discharge of 25-years plan