Judul: Water use for potato plant (Solanum tuberosum, L) using aeroponics system
Abstrak: Aeroponics is one solution to overcome the limitations of agricultural area. Aeroponics sytem has many advantages, one of them is the water usage efficiency. This study was conducted to calculate the water losses on potato plant using two lighting period treatments; 12 hours and 24 hours. The water losses from the 12 hours lighting period is about 0.12 mm/day, while the 24 hours loss 0.14 mm/day. The room temperature during the observation ranged from 19.00 C to 22.90 C. The measured temperature within 24 hours was 20.00 C–26.50 C. The low humidity affect the plant growth caused death of the plant. Air humidity that is measured within 24 hours was approximately 50%.
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Judul: Growth of Potato Plants (Solanum tuberosum L.) var. Atlantic and Super John in Response to Lighting Period of Fluorescent Lamp in Aeroponic System.
Abstrak: This study was conducted to find out responses of growth of seed potato (Solanum tuberosum L. var. Atlantic and Super John) to different lighting period of fluorescent lamp in an aeroponic system. The light source was provided by 40 W fluorescent lamps under 12 and 24 hours lighting. The total power was 320 W (8x 40 W) for 2.4 m2 with the distance between the light sources (lamps) and the plants was 30 cm. In this aeroponic system, the environmental condition which had low light intensity (average of 1149 lux or 9 W/m2.) and low humidity (48-53%) resulted a negative impact to the plant growth. The range of diurnal room temperature was 20.0 . 26.5 ¢ªC. Water was automatically sprayed for 13 seconds at 7 minutes interval to ensure the plant has sufficient water and nutrients. Plant growth was measured from total number of leaves. The study resulted that 24 hours lighting period had better effect on growth than 12 hours lighting period. The growth of Atlantic variety was better than Super John in response to the low intensity of light shown by higher leaf number both in 12 hours and 24 hours lighting period.
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Judul: Transisi Fasa Materi Hadronik ke Materi Kuark pada Inti Bintang Neutron.
Abstrak: Bintang neutron terdiri dari beberapa lapisan yang disusun oleh materi nuklir yang berbeda dengan kerapatan yang semakin tinggi ketika mendekati pusat bintang. Inti luar bintang neutron disusun oleh materi hadronik (nukleon, lepton, dan hyperon), sedangkan inti dalam bintang neutron disusun oleh kuark-kuark bebas (up, down, strange) yang saling berinteraksi. Tujuan penelitian ini adalah mempelajari bagaimana transisi dari inti luar ke inti dalam bintang neutron dengan menggunakan pendekatan RMF (Relativistic Mean Field) untuk materi hadronik dan CIDDM (Confined Isospin Density Dependent Mass) untuk materi kuark. Tekanan transisi diperoleh ketika potensial kimia barion materi hadronik dan materi kuark bernilai sama. Nilai tekanan transisi dengan parameter SU6-TM1 sekitar 87 MeV/fm3 dan diperoleh massa maksimum bintang neutron yaitu 1.92M dengan jari-jari sekitar 8.62 km. Nilai tekanan transisi dengan parameter SU6-G2 sekitar 53 MeV/fm3 dan massa maksimum bintang neutron yaitu 1.88M dengan jari-jari sekitar 8.16 km. Jenis transisi fasa adalah orde satu ditandai dengan diskontinuitas dalam kerapatan energi (adanya mixed phase). Parameter-parameter pada model nuklir yang digunakan menyebabkan perbedaan kekakuan persamaan keadaan (EOS) dari materi hadronik dan materi kuark sehingga nilai tekanan transisi dari fasa hadronik ke fasa kuark juga berbeda.
Keyword: bintang neutron, persamaan keadaan, transisi fasa