Judul: Analisis Neraca Energi Wilayah Pertanian Situ Gede, Bogor
Abstrak: The purposes of this research are studying the dynamics of atmospheric stability, determining the heat flux (Qh) and latent heat (Qe), determining and analyzing the energy balance on agricultural areas in Situ Gede, Bogor. This research uses the data of temperature, humidity, wind speed, radiation, and rainfall in 2011. Atmospheric stability that is analyzed consists of neutral, stable and unstable conditions. For the year, the stable condition occurred only at 19.9% of the total of the data of the atmospheric stability. The atmospheric conditions that are dominated by neutral conditions reached 48.5%. Unstable conditions reached 31.5%. On the agricultural areas in Situ Gede Qe = 4.92 MJ m-2 day-1, Qh = 3.35 MJ m-2 day-1, and Qg = 2.40 MJ m-2 day-1. It indicates that the energy needed to heat the atmosphere, evaporate water, and heat the soil surface is relatively small while the average net radiation is 12.78 MJ m-2 day-1 and the storage is 2.10 MJ m- 2 day-1. It shows the potential of energy utilization by plants.
Keyword: atmospheric stability, heat flux, the energy balance.

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.
Keyword: 

Judul: Hydroxyapatite-Chitosan Composite Coating on Stainless Steel 316 to Improve Corrosion Resistance
Abstrak: Metals that were used in bone implantation should have good corrosion resistance that were not easily corroded when implanted into the body. Metal corrosion resistance of stainless steel 316 can be enhanced through the metal coating by hydroxyapatite-chitosan composite with composition ratio of hydroxyapatite (gram) and chitosan 3% (mL) 0.2:0, 0.2:0.1, 0.2:0.5, 0.2:1.0, and 0.2:1.5. Besides improving the corrosion resistance of metal, the presence of chitosan also maintain the position of hydroxyapatite on metal surfaces. Corrosion resistance increases with increasing amount of chitosan added and the best composition of hydroxyapatite-chitosan composite was 0.2:1.0.
Keyword: