Judul: Karakteristik Kulit Kaki Ayam yang Disamak dengan Krom dan Mimosa serta Ekstrak Kulit Buah Salak (Salacca Edulis Reinw)
Abstrak: Leather tanning is a process to transform the unstable raw skin into more stable form. The aim of this research was to determine characteristics of chicken foot’s skin which tanned using mineral (chromium) and vegetable tanning material (mimosa and salak peel’s extract). This research used chicken foot’s skin tanned with one control and 3 treatments. Each treatment used similar materials, namely; chromium, mimosa and salak peel’s extract, with different concentration. Control treatment consisted of 100% chromium; treatment 1 consisted of tanning material with ratio of 70:20:10; treatment 2 with ratio of 60:20:20 and treatment 3 with ratio of 50:20:30. Each treatment had 3 replications. The observed variables were tensile strength, elongation and tear endurance. Data were analyzed by using analysis of variance. The results showed that tensile strength, elongation and tear endurance of chicken foot’s skin tanned with each treatment showed not significant different (P> 0.05) with the best treatment ratio was 50:20:30.
Keyword: tanning, salak peel, chicken claw’s skin, Bogor Agricultural University (IPB)

Judul: Karakteristik Kulit Ceker Ayam yang Disamak dengan Kombinasi Krom dan Mimosa serta Ekstrak Daun Teh (Camelia sinensis).
Abstrak: Skin tanning is process of converting rawhide skin protein into skin tanned by tanning materials, that result a change in the physical properties of unstable to stable and resistant to environmental influences such as physical pressure, weather, and microorganisms. Waste from tanning process is solid waste, gas, and liquid. For not polluting the environment, liquid waste containing chromium (0.7%) should be processed in the mix with natural tanning materials, like tea. This research used the skin of chicken claw that used combination of tanning (chemical tanning and tea extract) with different concentrations of chrome and nature tanning materials (mimosa and tea extracts) (70:20:10), (60:20:20) and (50:20:30), respectively. Parameters in this reseacrh was the quality of the skin tensile test, elongation test and skin rips test. The best concentration of tea extract for physical characteristics of the tanned chicken claw leather is addition of tea extract 10% intensile test, 20% tea extract in elongation test and 30% tea extract in skin rips test.
Keyword: Bogor Agricultural University (IPB), tea, tanning, eather

Judul: Approximation of the Median of Poisson Distribution Using the Relation of Poisson-Gamma Distribution
Abstrak: A major drawback of median is that median cannot usually be defined in closed form, even in the cases where their distribution functions are known. This study gives an approximation of the closed form for the median of the Poisson distribution by using the relation of Poisson-Gamma distribution. The approximation uses elementary techniques based on the monotonicity of certain sequences involving tail probabilities of the Poisson distribution and the Central Limit Theorem. Furthermore, a closed form expression for the mean absolute deviation 􀜧|􀜰􀰒 􀵆 􀜯􀝁􀝀􁈺􀜰􀰒􁈻| is also studied. The median is relevant because of the fact that it minimizes the mean absolute deviation of a Poisson random variable (􀜰􀰒􁈻 by considering median as central tendency.
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