Judul: Pengaruh waktu oksidasi terhadap mutu kulit Samoa pada proses penyamakan minyak yang dipercepat dengan Hidrogen Peroksida
Abstrak: Leather tanning is a process of modifying the structure of collagen fibres, so as to transform animal skin that decay easily, into leather which is durable and stable to the environmental influences. One of the leather products is oil tanned leather, known as chamois leather. It has unique uses for cleaning, drying, and filtration. It can be produced by using rubber seed oil and oxidizing agent of hydrogen peroxide. The best condition for the tanning needs to be applied in order to improve process efficiency and to obtain good quality leather. In this research, optimizations of oxidation times inside and outside the rotary drum in chamois tanning were investigated. The objectives of the research were to determine the best condition of oxidation time inside and outside the rotary drum for tanning process. The experiment was conducted by tanning of goat pickle pelts for 4, 6, and 8 hours of oxidation times inside the rotary drum and 1, 2, and 3 days of oxidation times outside the rotary drum. The chemical, physical, and organoleptic properties of the leather were measured. This study shows that the chemical, physical, and organoleptic properties met the quality requirements for the chamois leather. The best conditions for the tanning were an oxidation time of 8 hours inside the rotary drum and 1 day outside the rotary drum. The chemical properties of the leathers were oil content of 2.75%, ash content of 1.92%, and pH of 6.88. Their physical properties were thickness of 0.6 mm, shrinkage temperature of 71.63oC, water absorption of 291.36% (2 hours) and 323.89% (24 hours), tear strength of 59.45 N/mm, tensile strength of 26.18 N/mm2, and elongation at break of 163.33%. The organoleptic properties of the leathers, i.e. softness, colour, and odour were considered good.
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Judul: Penentuan Waktu Oksidasi Terbaik untuk Proses Penyamakan Kulit Samoa Menggunakan Minyak Biji Karet dengan Oksidator Natrium Hipoklorit
Abstrak: Chamois leather is a well known product, as it has specific uses for gasoline filtration, cleaning and drying of optical equipment, spectacles, mirror and vehicles. It can be produced by using rubber seed oil and oxidizing agent of sodium hypochlorite. The best oxidation time condition for tanning need to be applied in order to obtain good quality leather. The objectives of the research was to determine the best oxidation time condition for the tanning process. The experiment was carried out by tanning of goat pickle pelts for 4, 6, 8 hours of oxidation times inside the rotary drum and 1, 2, 3 days of oxidation times at a toggle dryer. This study shows that the chemical, physical and organoleptic properties of the leather met the quality requirements for the chamois leather. The best oxidation times for the process were 4 hours in the rotary drum and hang at toggle for 3 days. The chemical properties of the leathers were pH of 7.48, ash content of 1.99%, and oil content of 4.51%. Their physical properties were thickness of 0.7 mm, tensile strength of 30.20 N/mm2, elongation at break 178.09%, tear strength of 75.105 N/mm, and water absorption of 315.655% (2 hours) and 346.49% (24 hours). The organoleptic properties of the leathers, i.e. softness, colour and odour, were considered good to excellent.
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Judul: Pendugaan Fungsi Sebaran dalam Model Nonparametrik
Abstrak: Nonparametric statistics are alternative for parametric statistics whenever no assumptionis satisfied in parametric statistics, for example the distribution function is not identified. Nonparametric statistics are often referred as free distribution procedures, because they are not referred to any particular distribution. This paper discusses the estimation of the distribution function in nonparametric models. It emphasizes on nonparametric family. The objective of this research is tostudy nonparametric estimation models on the empirical distribution functions, denoted by that is independent and identically distributed (i.i.d.) and is maximum likelihood for unknown distribution function. is unbiased estimator of with or as an uniformly minimum variance unbiased estimator (UMVUE) and -consistent for .
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