Judul: Seaweed Cellulose Microfiber Aerogel: Application  of Active Packaging Material to Absorb Carcinogenic Polycyclic Aromatic  Hydrocarbon Compounds in Smoked Fish
Abstrak: Polisiklik aromatik hidrokarbon (PAH) pada ikan asap cenderung mencapai tingkat yang tinggi bahkan melebihi batas maksimum, dan berpotensi sebagai senyawa karsinogenik. Aerogel sebagai alternatif ideal untuk menyerap senyawa PAH dan membuka peluang baru melalui pengembangan kemasan aktif. Penelitian bertujuan menentukan karakteristik aerogel mikrofiber selulosa dari rumput laut dengan teknik pengeringan berbeda dan aplikasinya sebagai material kemasan aktif penyerap senyawa karsinogen polisiklik aromatik hidrokarbon pada ikan asap. Metode berfokus pada pembuatan dan penentuan karakteristik aerogel mikrofiber selulosa dari rumput laut Sargassum sp. menggunakan freeze drying dan dehydrator serta efektivitas penyerapan senyawa PAH pada ikan asap. Aerogel mikrofiber selulosa dari rumput laut melalui freeze drying memperlihatkan keunikan struktur 3D berpori dengan ukuran 16,250 nm, sedangkan dengan dehydrator cenderung memiliki struktur yang padat dengan ukuran pori 12,081 nm. Aerogel mikrofiber selulosa dari rumput laut secara umum cukup efektif dalam menyerap senyawa PAH, yaitu anthracene., Polycyclic aromatic hydrocarbons (PAH) in smoked fish tend to reach high levels, even exceeding the maximum limit, and have the potential to be carcinogenic compounds. Aerogel is considered an ideal alternative to absorb PAH compounds and opens up new opportunities through the development of active packaging. This research aims to determine the characteristics of cellulose microfiber aerogel from seaweed using different drying techniques and its application as an active packaging material to absorb polycyclic aromatic hydrocarbon carcinogenic compounds in smoked fish. The method focuses on making and determining the characteristics of cellulose microfiber aerogel from seaweed Sargassum sp. using freeze drying and dehydrator and the effectiveness of absorption of PAH compounds in smoked fish. Cellulose microfiber aerogel from seaweed through freeze drying shows a unique 3D porous structure with a size of 16,250 nm, whereas with a dehydrator it tends to have a dense structure, but has a pore size of 12,081 nm. Cellulose microfiber aerogel from seaweed is generally quite effective in absorbing PAH compounds, including anthracene.
Keyword: absorbents, biomaterials, food safety, freeze drying, hydrogels

Judul: Daya tahan kemasan antimikroba berbahan baku karagenan dan agar-agar
Abstrak: Active packaging is one of the technique that can be developed to prolong shelf-life; enchance safety or sensory properties while maintaining the product quality. Active packaging is a packaging teclmique where the packing material has an active interaction with the product. One example of the active packaging is antimicrobial (AM) film with garlic extract as the AM agent. Fish ball was choosen in this research as a product for application of AM film, since it is a perishable product. Generally, fish ball used chemical preservatives to prolong its shelf-life. The preservatives sometimes off course can cause the health problems. Garlic is believed had capability against such bacterial growth of E. coli, S. typhimurium and S. aures. The purpose of this research is to investigate the effectivity of AM film base on carrageenan and agar-agar againts E. coli, S. typhimurium and S. aures. Further more this research is also dedicated to find the quality of fish ball coated by AM film during storage at different temperature. This research was consist of three steps: (i) product on AM of film, (ii) investigating the activity of AM film against microorganism growth, (iii) analyzing product quality during storage.
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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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