Judul: Penentuan Konsentrasi Bahan Penyamak Aldehida dan Minyak Biji Karet untuk Penyamakan Kulit Samoa pada Skala Pilot Plant
Abstrak: Research on chamois tanning using rubber seed oil on a laboratory scale has achieved optimum results. Therefore,further research is directed toward the pilot plant scale before entering mass production for the commercialization. This study aimed to determine the effects of glutaraldehyde concentrations (3% and 5%) and rubber seed oil concentrations (20% and 30%) and also to determine the best combination of treatments. This study shows that the concentration of rubber seed oil significantly affected oil content and tensile strength. The concentration of glutaraldehyde had a significant effect on tear strength and tensile strength. Interaction of these two factors significantly affected the tensile strength of chamois leather. Combination treatment of rubber seed oil concentration of 20% and 3% glutaraldehyde concentration gave the best results. The physical properties were tensile strength of 30.1 N/mm2, elongation of 112.6%, tear strength of 81.57 N/mm, 2 hours water absorption of 345%, 24-hour water absorption of 409.9%. The chemical properties were oil content of 5.9%, ash content of 1.2%, and pH of 6.7. The organoleptic properties were softness 8 (good), colours 8-9 (very good), and odour 8-9 (very good). This best result was similar with or may be as good as the best result on laboratory scale. Therefore, chamois leather production process technology of rubber seed oil is ready to be produced on a larger scale for the purpose of commercialization by considering economic value
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Judul: Pengaruh Konsentrasi Natrium Perkarbonat dan Jumlah Air Terhadap Mutu Kulit Samoa Pada Penyamakan Kulit Dengan Minyak Biji Karet.
Abstrak: Chamois leather is a popular product in trading, because it has specific uses. Nowadays, chamois leather is produced with fish oil as a main oil tanning agent. The problem are odors and colour of the product as well as the expensiveness of the fish oil. To overcome the problem, subtitution of the fish oil with vegetable oil, such as rubber seed oil. May be carried out other problem is oxidation needs a long time, such as about 2 weeks. This causes production process of tanning leathers tanning chamois needs long time. The objectives of this research were to understand the effect of amounts of sodium percarbonate and water in chamois leather tanning using rubber seed oil on the quality of the chamois leather. Besides that, this research also aimed to get the best combination of the factors. The preliminary research was carried out by analyzing the physico-chemical properties of rubber seeds oil. The main research was done by tanning of sort skin pickeld pelt. In its oxidation, combination of 2%, 4%, and 6 % of sodium perkarbonat and 70%, 50% dan 30% of water were used. The experimental design used was completely random factorial design. The results of preliminary research were rubber seed consisted of 49% shell and 51% endosperm. The characteristics of the rubber seed oil were density of 0.94 (g/cm3), viscosity of 48.4 centistokes, colour of 2713 PtCo units, acid value of 15.2 mg KOH/g oil , FFA of 5.82 %, iodine number of 113 g iodine/ 100 g oil, saponification value of 350.06 mg KOH/g oil, and peroxide number of 24.13 miliekuivalen/1000 g oil. The main research show that sodium percarbonate amount significantly affected thickness and oil content; amount of water significantly affected oil content of the leather; The interaction between sodium percarbonate and water significantly affected ash content and oil content. The optimum conditions for the oxidation were amount of sodium percarbonate of 4% and water at 50%. The physical properties of the leather were shrinkage temperature of 71oC, thickness of 0.87 mm, tensile strength of 35.95 N/mm2, elongation of 129%, tear strength of 82.01 N/mm, water absorption of 226% (2 hours) and 303% (24 hours). The chemical properties were pH of 7.45, oil content of 8.1% and ash contain of 1.3%. The organoleptic properties were softness of 6 – 7, colour of 7 - 8, and odour of 7 – 8.
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Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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