Judul: Pengaruh jenis dan kadar ekstender kulit akasia (Acacia mangium Willd) terhadap kualitas papan partikel yang dihasilkannya
Abstrak: INTRODUCTION : The usage of synthetic adhesive has already been increased along with the development of the composite’s wood industry which turns into the scarcity of raw materials synthetical adhesives resources. Therefore, we need an alternative to save the usage of synthetic resin adhesives by replacing with some of the resin which also has a function as an extender. The potency of industrial timber estate’s (HTI) wood bark waste, especially from acacia wood species (Acacia mangium Willd) is so bright in the future along with acacia plantation development. The availability of the wood bark waste in Indonesia is quite plentiful so that the chances of its utilization as a mixed material adhesive composite boards is really possible. One of the utilization of wood bark waste is to produce a product which has high added value by using the tannin substances which was contained as an adhesive or as an extender for wood composite production.
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Judul: Pengaruh perlakuan pendahuluan dan kadar perekat terhadap kualitas papan partikel limbah kayu sagu (Metroxylon spp.)
Abstrak: Salah satu upaya pemanfaatan limbah pengolahan sagu adalah melalui pembuatan papan partikel. Dengan digunakan sebagai bahan baku papan partikel, limbah tersebut diha- rapkan dapat meningkat nilainya. Kualitas papan partikel dipengaruhi oleh berbagai faktor, dua diantaranya adalah kualitas bahan baku dan perekat. Kadar zat ekstraktif merupakan sifat bahan baku yang mempengaruhi konsumsi perekat, laju pengerasan pere- kat dan daya tahan papan partikel yang dihasilkan (Malo- ney, 1977). Berbagai upaya dilakukan untuk memperbaiki sifat bahan baku, antara lain perlakuan pendahuluan berupa perendaman dingin dan panas. Sedangkan perekat merupakan faktor penting, karena hampir keseluruhan sifat papan partikel dipengaruhi perekat yang digunakan (Kollmann dkk, 1975). Penelitian ini bertujuan untuk: (1) mengetahui pengaruh perlakuan pendahuluan berupa perendaman dingin dan panas partikel kayu sagu, serta kadar perekat terhadap kualitas papan partikel, (2) pengaruh bahan baku dan kadar perekat terhadap kualitas papan partikel limbah kayu sagu. ...
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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