Judul: Mempelajari pengaruh berbagai perlakuan kemasan untuk mempertahankan kesegaran dan kualitas buah salak cv.suwaru selama penyimpanan
Abstrak: Salak (Sallaca edulis, Reinw) adalah tanaman asli Indo- nesia. Berdasarkan survei majalah Trubus (1986), dari 20 jenis salak yang ada di Indonesia terdapat satu jenis yang diklasifikasikan sebagai buah unggul nasional tahun 1991, yaitu salak Suwaru. Buah salak ini umumnya dikonsumsi dalam bentuk segar, sehingga perlu penanganan lebih lanjut untuk mempertahankan kesegaran dan mutunya selama distribusinya. Penelitian ini terdiri atas penelitian pendahuluan dan penelitian utama. Penelitian pendahuluan terbagi dalam 2 tahap, yaitu tahap penentuan titik "kesetimbangan gas" (5,7 % CO2 dan 3,930) dan tahap penentuan konsentrasi CO2/02 (2,5 CO2 dan 10 % 02) yang diamati setiap 6 jam untuk keperluan perlakuan penyimpanan dengan sistem atmosfir termodifikasi (penambahan gas awal) pada penelitian utama. Bahan yang digunakan dalam penelitian ini adalah buah salak Suwaru (kematangan 3- 4 bulan), plastik PE ketebalan 40 µm, kertas "chusioning material", lilin konsentrasi 6%, kotak karton gelombang (25 cm x 25 cm x 15,5 cm) dan kotak anyaman bambu (25 cm x 25 cm x 13 cm). Rancangan percobaan yang digunakan adalah rancangan acak lengkap dengan peubah...
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Judul: Pengaruh Jenis Kemasan Dan Suhu Penyimpanan Terhadap Kesegaran Dan Kualitas Buah Salak Padangsidimpuan (Salacca sumatrana)
Abstrak: This study aims to obtain the storage temperature and type of packaging which suitable for salak Padangsidimpuan. The research was conducted in two stages, i.e. preliminary research and primary research. Preliminary research carried out by measuring the initial quality (total weight lose, perishable fruit, water content, total titrated acid, total soluble solids, vitamin C and organoleptic). The results and than are used as initial data to conduct primary research. Primary research was conducted by coated 1 kg of salak and then packed with cartons, bamboo basket, plastic PE with cartons and plastic PE with bamboo basket. All samples were storaged in at 15oC and room temperature. Salak without treatment was also stored at room temperature as a control. Samples were analyzed the qualities every three days. Based on this research, physico-chemical characteristic of salak Padangsidimpuan showed that the water content was 78.12%, total titrated acid was 6.34%, total soluble solids was 15oBrix, vitamin C was 1.87 mg/100 g fruit, the preference score for color was 4, aroma was 4, flavor was 3, texture was 3 and general acceptance was 3. Based on the ANOVA analysis, Duncan test and “t” test, can be concluded that salak Padangsidimpuan were stored at a temperature of 15oC hold maximum of 30 days, with cartons, bamboo basket, plastic PE with cartons and plastic PE with bamboo basket. However the best condition of packaging resulted from this research was bamboo basket in 15oC.
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Judul: Dynamical System of Hepatitis B in Three Groups with Vaccination
Abstrak: The aim of this study is to modify the hepatitis B transmission model in three age groups involving vaccination from the model conducted by Zhoe and Zhang.The method used is to analyze the stability of the fixed point and its basic reproduction number (R_0). Performed stability analysis and numerical simulation to see population dynamics. Next, a sensitivity analysis of the parameters was carried out to see its effect on R_0. From the analysis obtained two fixed points, namely non-endemic and endemic fixed points. Non-endemic fixed points are locally asymptotically stable if R_0 <1 Meanwhile, the endemic fixed point is locally asymptotically stable if R_0 > 1. Hepatitis vaccination affects the number of susceptible population, because the more successful the vaccination, the smaller the number of susceptible populations so that the smaller the population will be infected.
Keyword: Dynamic, Hepatitis B, Vaccine, Mathematical model