Judul: Uji Kinerja Pemanfaatan Membran Reverse Osmosis pada Mesin Pendingin Absorpsi LiBr-H20
Abstrak: Absorption refrigeration system LiBr-H2O is an alternative refrigeration system to substitute vapor-compression refrigeration system, which has negative impact to environment and using mechanical energy for its operation. However, the absoption refrigeration system still needs thermal energy to regenerate the refrigerant from its absorber. The purposes of this study is to study the performance of reverse osmosis membrane to regenerate refrigerant H2O from the LiBr-H2O in absorption refrigeration system and to calculate the COP of the system. The experiment was conducted intermittently, where regeneration and refrigeration process occured separately. The study uses 3 level of LiBr-H2O concentration, namely 30%, 25%, and 20% with a variety of pressure treatments. The result of this research shows that COP of the system at concentration of 30% was 0.130 – 0.270, at concentration of 25% was 0.035 – 0.055, and at concentration of 20% was 0.015 – 0.020
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Judul: Studying rate of absorption steam by solutions Lithium Bromide (LiBr) as absorbant in absorption refrigeration
Abstrak: Absorption is the process of absorbing a fluid by another fluid to form a fluid solution. In absorption refrigeration system, LiBr as absorbent filters on components of the absorber will absorb water vapor with lower pressure than the evaporator pressure. The rate of absorption of water vapor is a function of concentration, temperature, humidity and pressure of water vapor. The goal of this research is to see the effect of concentration, temperature and vapor pressure of water at the rate of absorption of water vapor by aqueous absorbent filters (LiBr-H2O) in relation to the cooling system, to determine the equilibrium concentration absorption solution of LiBr-H2O, and to determine the sorption isotherm model. Equilibrium concentration is a function of temperature and humidity. Ce at 40oC and RH 60% was found 37%; at 40oC and RH 70% was 34%; at 40o and RH 80% was 29%; at 45oC and RH 60% was 37.5%; at 45oC and RH 70% was 36%; and at 45oC and RH 80% was 34.5%. The calculation results of Qe using Qe sorption isotherm model on temperature 40oC and 45oC were not too different. The calculation results of the percentage errors between Qe data and model from each of the humidity, obtained the lowest percentage of errors in model Freundlich was 0.4% in RH 60% and 70%; 0.3% in RH 80%.
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Judul: Bantalan Duduk Monyet Sulawesi
Abstrak: Kepulauan Sulawesi memiliki tingkat endemisitas fauna yang tinggi. Tujuh spesies monyet dari genus Macaca (macaques) adalah contoh fauna endemik tersebut. Mereka mempunyai sepasang bantalan duduk yang disebut ischial callosities. Bantalan duduk ini sangat beragam bentuknya. Selama ini, keragaman bentuk tersebut baru dideskripsikan secara verbal. Namun, ~ndeskripsian secara verbal tidak mampu mencakup keseluruhan variasi bentuk :%,ang ada dan membuat rekonstruksi bentuk menjadi subjektif. Pencakupan variasi ~entuk yang optimal dan rekonstruksi bentuk yang objektif dapat dilakukan ~elalui analisis kuantitatif. Penelitian ini bertujuan untuk menganalisis secara ;'-'uantitatif bentuk dari bantalan duduk monyet~monyet di Sulawesi menggunakan ~ua perangkat morfometrika geometris yaitu Thin-plate Spline dan Generalized ~rocrustes Analysis. Dua spesies lainnya dari genus Macaca yang berada di ~ekitar Sulawesi juga diikutsertakan sebagai pembanding. Hubungan antar bentuk -:clan arah perubahannya dapat ditentukan dari hasil kuantitatif ini. Bantalan duduk ::::I ~onyet Sulawesi mempunyai keragaman yang lebih besar dibandingkan M [ascicu!aris dan M nemestrina. Penyebab utama variasi adalah perbedaan pad a ;ragian dorsal dan pelekukan bantalan duduk. Terdapat tiga tipe bentuk bantalan &tiuduk pada monyet Sulawesi, yaitu oval tanpa pelekukan (M tonkeana dan M ~naurus), oval dengan pelekukan ke luar (M ochreata dan 1111. brunnescens), dan ::Oval atau seperti ginjal dengan pelekukan ke dalam (M hecki, M nigrescens, dan &V: nigra). Penyebaran tipe-tipe tersebut sesuai dengan penyebaran monyet' §nonyet di Sulawesi saat inL Arah perubahan bentuk bantalan duduk bermula dari 'bentuk oval yang dimiliki spesies di daerah tengah dan selatan pulau. Pelekukan ke arah luar berkembang di bagian tenggara pulau, sedangkan pelekukan ke dalam berkembang di bagian utara pulau.
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