Judul: Analisis Pindah Panas pada Pipa Pendingin untuk Zone Cooling dalam Sistem Hidroponik
Abstrak: Pada siang hari ketika cuaca cerah, air yang didinginkan dengan chiller di dalam zone cooling system untuk daerah perakaran dalam budidaya tanaman secara hidroponik mengalami kenaikan suhu sepanjang pipa pendingin. Pindah panas terjadi sepanjang pipa pendingin, dari daerah perakaran ke pipa pendingin. Analisis pindah panas sepanjang pipa pendingin tersebut adalah sangat penting dalam perancangan zone cooling system tersebut. Tujuan dari penelitian ini adalah (1) melakukan analisis pindah panas pada pipa pendingin untuk zone cooling dalam sistem hidroponik, (2) melakukan validasi model pindah panas untuk memprediksi suhu air pada posisi outlet pipa pendingin, dan (3) melakukan simulasi komputer untuk berbagai bahan pipa dan panjang pipa untuk beberapa kondisi termal rumah tanaman. Model pindah panas telah dikembangkan dari persamaan-persamaan pindah panas dan aliran fluida didalam pipa. Validasi model pindah panas dilakukan dengan membandingkan angka suhu air hasil prediksi dengan hasil pengukuran dalam grafik regresi linear. Hasil validasi menunjukkan bahwa model pindah panas tersebut dapat digunakan untuk memprediksi suhu air pendingin pada posisi outlet pipa pendingin. Model pindah panas tersebut dapat digunakan dalam pemilihan bahan dan ukuran pipa serta penentuan jarak antar pipa pendingin.
Keyword: Hydroponics, Heat transfer analysis, Root zone cooling, Water flowing, Cooling pipe, Hydroponic culture, Cooling system, Transfer model, Water temperature, Computer simulation

Judul: Analisis Pindah Panas pada Pipa Utama Sistem Hidroponik Substrat dengan Pendinginan Larutan Nutrisi
Abstrak: Cooled nutrient solution will have temperature rises during distributed to the root zone of the plants. The aim of the research was to analyze the heat transfer from environment to the main pipe of irrigation for hydroponic substrate system, to validate the heat transfer model, and to simulate inlet temperature for nutrient solution cooling planning. Heat transfer model was developed from heat transfer and fluid flow in pipe equations. Validation of heat transfer model was done using linear regression analysis method. Simulation was done by calculating temperature of inlet nutrient solution which is proper to get optimum temperature for plants using validated heat transfer model. The result of heat transfer model validation showed that the heat transfer model is fairly accurate to predict the temperature of nutrient solution in the main pipe. The simulation result showed that to obtain 20 °C temperature of nutrient solution at the end of ¾ inch PVC uninsulated main pipe with a length of 20 m, the inlet nutrient solution must be cooled to temperature of 18.06 °C.
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Judul: Categorization in Macaca fascicularis.
Abstrak: Categorization is an ability to group individuals or events into different classes mediated by conceptualized mental images. There are several levels of categorization and within a taxonomy the levels are nested. At the most concrete level of categorization, all or most members of the category shared common physical attributes that differ from other categories. The higher the level of category, the fewer common attributes between members of the group. In addition to humans, the ability to categorize has also been proposed in animals. One example of categorization in animal is species discrimination. Using matching-tosample task, present experiment tested ability of the long-tailed macaque (Macaca fascicularis) in discriminating dichotomous-stimuli of different animals. The species has been shown to be able to see photos as representations of real object so I used facial photos of humans and animals for the stimuli. First, I tested their ability to classify humans and macaques into separate group. Second, I tested their ability to discriminate their conspecific from other macaques. And the last, I tested whether the subjects were able to discriminate non-human animals from humans. In all of these experiments I found that the subjects showed high performance in categorizing objects, even when I discarded details of visual informations, such as color and local shapes. The ability to identify objects with reduced representation of physical properties means the subjects were able to generalize attributes of members of the group. This would indicate that the subjects created a higher level abstraction. On the other hand, in discriminating intrageneric macaque species I found that they were able to extract uniqueness of each species. More over, I also found that the subjects were able to put photos of non-human animals that shared very few similarities in physical percepts into one group. I suggested that the subjects could create a more abstract concept based on non-percepts relations as a basis to put the objects into one category. Thus, I concluded that M. fascicularis were able to perform multiple levels of categorizations.
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