Judul: Analisis Karakteristik Parameter-Parameter Atmospheric Boundary Layer dengan Data Radiosonde (Studi Kasus : Kota Serang)
Abstrak: Atmospheric Boundary Layer as the air layer directly affected by the earth’s surface where the surface effects (friction, heating and cooling) felt directly on a time scale less than a day. Case study in this paper is Serang. The data used is the radiosonde data. In describing the atmospheric boundary layer requires a parameter, such as the virtual potential temperature, mixing ratio, and wind speed. Sketch the pattern of vertical virtual potential temperature continued to rise during the day on SL layer, then decreased and more homogeneous in the ML layer, increased in tiitk CI with the result that CI is higher than the night, early morning, or late afternoon. Vertical profiles of Mixing ratio, maximum humidity during the day will continue to decline at the surface and in the lining of SL, when entering the ML layer, as the turbulence becomes homogeneous, and when it reaches the CI. Wind speeds in Region Attacking at night more than early morning (01.00) morning (at 07.00) and afternoon (13:00), it is because there is a strong influence of intense turbulence during the day.
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Judul: Kajian Atmosfer Bawah Wilayah Tropis dan Subtropis
Abstrak: Planetary Boundary Layer is the lowest part of the atmosphere directly affected by the earth’s surface and responds to surface forcings within a time period of hourly to daily. The thickness of boundary layer varies over space and time, ranging from hundreds of meters to a few kilometers. The objective of this study consist of the analysis of Boundary Layer based on diurnal and nocturnal vertical profiles of meteorological properties and identification of characteristics pertaining to tropical atmosphere (represented by Soekarno-Hatta (6.110S, 106.650E), Polonia (3.560N, 98.680E), and Da Nang (16.030N, 108.200E) stations) and subtropical atmosphere (represented by Perth (31.930S, 115.960E), Nanjing (32.000N, 118.800E), and Hakasskaja (43.780N, 87.620E) stations). Virtual potential temperature, specific humidity, wind speed and direction, atmospheric stability, and Bulk-Richardson number are used to estimate the boundary layer thickness. Vertical profile of the virtual potential temperature and specific humidity are used to determine the Mixed Layer heights during the day and Residual Layer heights during the night. On the other hand, the mean value of Turbulent Flow Thickness is derived from the vertical profile of the Bulk-Richardson number (RiB). Analytical results of this study revealed that Mixed Layer height in the tropical atmosphere varies in a range from 260 m to 1410 m, Residual Layer height varies in a range from 267 m to 925 m, whereas the Turbulent Flow Thickness variation is confined between 0 m to 335 m. In subtropical atmosphere Mixed Layer height varies in a range from 101 m to 1483 m, Residual Layer height varies in a range from 121 m to 1276 m, whereas the Turbulent Flow Thickness variation is confined between 0 m to 769 m. This study also revealed that, except during summer, Mixed Layer Heights in the tropics are normally higher than in the subtropics.
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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.
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