Judul: Pemurnian Minyak Ikan Lemuru (Sardinella sp.) Menggunakan Sisik Ikan Mas (Cyprinus Carpio) dan Cangkang Simping (Placuna placenta)
Abstrak: Generally fish oil as by product of lemuru flouring industry is low quality so it can not be safely consumed. Purification using adsorbent is a method to improve the quality of fish oil. Adsorbents from capiz shell (Placuna placenta) and carp scales (Cyprinus carpio) were used with the concentration of 3 %, 5 %, and 7 %, respectivelly. The results showed purification using adsorbent could reduce free fatty acids from 1,4 - 2,42 %, acid value approximately 2,78 - 4,81 mgKOH/g, peroxide of 2,96 - 5,33 meq/kg, anisidin value from 0,42 - 3,88 mmol/ kg, and the totoks value 6,34 - 14,55 meq/kg, and increased purity from 62,45 - 98,4 %. The best result was obtained from capiz shell at 7 %.
Keyword: shell, scale, fish oil, adsorbents

Judul: Penggandaan Volume Pemurnian Minyak Ikan Lemuru (Sardinella sp.): Semirefined dan Bleaching
Abstrak: Semirefined dan bleaching merupakan metode pemurnian untuk menghilangkan komponen pengotor dan meningkatkan kualitas minyak. Penggandaan volume pemurnian adalah upaya memurnikan sampel kasar pada skala yang lebih besar. Penelitian ini bertujuan untuk menentukan profil asam lemak minyak ikan hasil samping penepungan lemuru (Sardinella sp.), menentukan perlakuan terpilih konsentrasi natrium hidroksida (NaOH) dan adsorben Miracle Filter Powder (MFP) dalam proses pemurnian ikan lemuru, serta menentukan pengaruh penggandaan volume terhadap kualitas minyak ikan hasil pemurnian. Kadar asam lemak bebas minyak ikan hasil samping penepungan lemuru adalah 0,77% dan bilangan peroksida 16,54 meq/kg. Perlakuan terpilih semirefined NaOH 14°Be menurunkan bilangan peroksida tertinggi, yakni 44,62%. Perlakuan terpilih bleaching MFP 3% menurunkan bilangan peroksida tertinggi, 18,44%. Kadar asam lemak bebas minyak ikan hasil semirefined dan bleaching berkisar 0,52%-0,81%. Perlakuan terpilih penggandaan volume semirefined dan bleaching minyak ikan lemuru adalah skala 250 g. Kejernihan minyak ikan cenderung meningkat setelah proses bleaching.
Keyword: Bleaching, By product, Fish oil, Purification, Semirefined, Fatty acid, Oil lemuru, Asam lemak bebas, Total oksidasi, Peroksida

Judul: Bifurkasi Hopf pada Model Siklus Bisnis Kaldor Kalecki tanpa dan dengan Waktu Tunda
Abstrak: Business cycle model is one of dynamical system models in economic. One of the business cycles model is Kaldor-Kalecki model. Kaldor-Kalecki business cycle model that is written in delayed defferential equations, is a business cycle model that involves gross product and capital stock of a company. In this paper Kaldor-Kalecki business cycle model is analyzed using both nondelay and delay in time of capital stock. By Taylor expansion for the time delayed model, an analysis of stability around the fixed points has been done. Furthermore, by using Hopf bifurcation theorem, it can be shown that there exists periodic orbits and limit cycle. In the nondelayed model, changing the parameter of goods market could lead to the occurrence of Hopf bifurcation and the existence of limit cycle. Similarly, for the delayed model, it has been shown that changing the time delay parameter may result in the occurrence of Hopf bifurcation and limit cycle.
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