Judul: Proyeksi Penduduk dengan Proses Kelahiran dan Kematian
Abstrak: A population projection is a scientific calculation based on certain assumptions of births, deaths, and migration. These three components determine the size of the population in the future. The aims of this study are to develop population projection model using birth and death process and to apply the model to Indonesian population data. This study uses four steps of modelling process. First, we develop a model of birth and death process with migration. Second, we verify the model using 1990 Indonesian population data and compare the result with the real data. Third, using the model we estimate population projection for the years 2000-2025 based on Indonesian population data of the year 2000 and compare the result with population projection for years 2000-2025 by BPS. Finally, we estimate population projection for years 2010-2035 based on Indonesian population data of the year 2010. The advantage of this model is that we can give the confidence interval of the estimate besides the value of estimation. The difference between our projection based on 1990 Indonesian data and the real data is below 10%, and the difference between our projection based on Indonesian data of the year 2000 and projection by BPS is less than 6%.
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Judul: Analysis of stable and quasi-stable population growth models
Abstrak: Model pertumbuhan penduduk merupakan hal yang penting dalam mengantisipasi persoalan ekonomi, social, dan politik dalam suatu bangsa yang diakibatkan oleh perubahan jumlah penduduk. Perubahan jumlah penduduk dapat dipengaruhi oleh faktor fertilitas, mortalitas , dan migrasi. Karya ilmiah ini bertujuan untuk memodelkan pertumbuhan penduduk stabil dan kuasi-stabil lalu mengaplikasikannya dalam penduduk Indonesia tahun 2000, 2005 dan 2010. Hasil proyeksi akan dibandingkan dengan data sensus lalu akan diperoleh nilai galatnya. Hasil penelitian menunjukkan bahwa model kuasi-stabil dengan adanya faktor perbaikan kematian lebih baik daripada model stabil. Berdasarkan model kuasi-stabil hasil proyeksi penduduk Indonesia tahun 2015 sebesar 255,236,560. Keywords : pertumbuhan penduduk, kuasi-stabil, fertilitas, mortalitas., Model of population growth is essential to anticipate problems in the economic, social and political in a nation that affected by the change of population. Changes in a population can be affected by factors of fertility, mortality, and migration. This paper aims to model stable and quasi-stable population growth and then applies these models to population of Indonesia for 2000, 2005 and 2010. The projection results is compared to the census data and then error value will be obtained. The results showed that the quasi-stable model with mortality improvement factor is better than the stable model. Based on the quasistable model, prediction of population of Indonesia in 2015 is 255,236,560. Keywords: population growth, quasi-stable, fertility, mortality
Keyword: pertumbuhan penduduk, kuasi-stabil, fertilitas, mortalitas

Judul: Characterizations of low alloy steel sae 4422  plated with chromic acid (Cro3)
Abstrak: Characterizations of low alloy steel SAE 4422 plated with chromic acid (CrOrO3) was use Optical Microscopy (OM), Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), RD),Energy Dispersive Analysis of X-Ray (EDAX), Hardness Test and Roughness Test. Microstructures analysis exhibits cracks and grain boundaries microcracks as a characteristics of chrome metal found at plating metal. Perlite and Ferrite as grains of steel found at base metal with grain boundaries around it. Phase analysis of plating metal appropriate to chrome metal with lattice constant (a) is 2.559 Å and phase analysis of base metal appropriate to iron ferrite with lattice constant (a) is 3.318 Å. Both plating and base metal have cubic system. Chemical analysis of plating metal at surface section exhibits that cracks area have highest value of carbon element compare with grains and grains boundaries area. While chemical analysis of base metal at cross section exhibits that perlite have highest value of carbon element compare with ferrite and grain boundaries. The hardness value of plating metal at surface section and cross section are 753 and 637 VHN. While, the hardness value of base metal and interface area at cross section are 205 and 373 VHN. The roughness value at measurement points of chrome surface for as received sample are 0.445 μm. Observation used Optical Microscopy and Scanning Electron Microscopy exhibits surface irregularities combine to form surface texture of plating metal at surface section.
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