Judul: Analisis Pindah Panas pada Sistem Pemanas Tambahan Alat Pengering Surya Hibrid-Tipe Rak Berputar untuk Sawut Ubi Jalar
Abstrak: Auxiliary heater on GHE-Hybrid heating instrument is one of important part in heating process. Heat loss on the system can affect heating process. The aim of this research is to find water heating system efficiency and effectiveness of the heat exchanger, and determine the mathematical model of energy balance on drying stove system by analyzing heat transfer occured on auxiliary heater. Based on result, efficiency on water heating system and stove was 52-56 %, the highest heat loss on inlet air in the stove was 1800-2525 watt. The average of the effectiveness of the HE1 and HE2 respectively were 0.35 and 0.65, while the value of NTU respectively were 0.42 and 1.21. This estimation of simulation modeling can be applied, indicated by error of 5%. Base on the heat transfer analysis, stove and water heating system yield the highest heat loss, so auxiliary heater system need to be modified, such as: by adding the cover stove, expanding HE2 heat transfer area, increasing pump power and fan, and increasing biomass input rate.
Keyword: efectiveness, efficiency, heat exchanger, heat transfer

Judul: Analisis Heat Exchanger pada Pengering Efek Rumah Kaca Hybrid Tipe Rak untuk Pengeringan Ubi Jalar
Abstrak: Peranan penukar panas sangat penting pada pengering Efek Rumah Kaca (ERK) hybrid namun, efektivitas dan efisiensi termal penukar panas pada umumnya masih rendah. Tujuan penelitian ini adalah melakukan analisis sistem penukar panas berupa efektivitas penukar panas, efisiensi termal penukar panas, efektivitas sirip, efisiensi sirip dan kehilangan panas serta memberikan saran atau rekomendasi untuk meningkatkan unjuk kerja penukar panas. Metode Log Mean Temperature Difference (LMTD) digunakan untuk menganalisis penukar panas. Berdasarkan hasil analisis diperoleh efektivitas Heat Exchanger (HE) keseluruhan sebesar 0.44-0.87 dengan rata-rata sebesar 0.696 dan nilai efisiensi termal sebesar 3.2%-86.6% dengan rata-rata sebesar 50.82%. Pada analisis sirip, diperoleh nilai efisiensi sebesar 0.961-0.966 dengan rata-rata sebesar 0.964 dan efektivitas sirip tunggal sebesar 1.967-1.978 dengan rata-rata sebesar 1.974. Kehilangan panas pada sistem penukar panas masih terjadi diataranya pada dinding depan dan belakang dengan rata-rata total sebesar 388.06 W dan perbandingan kehilangan panas terhadap energi yang dihasilkan tungku sebesar 11.35%.
Keyword: efektivitas, efisiensi, penukar panas, sirip

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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