Judul: Penggunaan Metode Perturbasi Homotopi untuk Menyelesaikan Persamaan Burgers dan Penerapannya pada Masalah Arus Lalu Lintas
Abstrak: Traffic flow problems are frequently referred as problems of congestion, accidents and traffic violations. Traffic accidents often occur because the vehicle drivers can not control the speed of their vehicle. One of the efforts that must be made by the vehicle drivers to control the speed of their vehicle is driving under the road speed limit. On this traffic flow problems, the road speed limit will be assessed based on the Burgers equation. The Burgers equation can be solved by the homotopy perturbation methods. The results of the homotopy perturbation method will be compared to the results of numerical methods.
Keyword: traffic flow problems, homotopy perturbation method, Burgers equation

Judul: Penggunaan Metode Perturbasi Homotopi pada Penyelesaian Persamaan Aliran Busa Cair
Abstrak: Aqueous foam drainage inside Plateau border affects the structure of foam. Foam becomes fragile when it dries due to reduction of liquid flow. The distribution of liquid flows inside Plateau border which affects the structure of foam can be described mathematically in form of aqueous foam drainage equation. In this paper, aqueous foam drainage equation is solved by homotopy perturbation method. In homotopy perturbation method, the solution of this equation assumed in the form of power series. By giving the exact initial approach, the solution of this equation using homotopy perturbation method can estimate the exact solution with a small error rate.
Keyword: aqueous foam drainage equation, homotopy perturbation method, Plateau border

Judul: Phycocyanin Extract From Spirulina platensis for as an Antioxidant and Biopigment for Spherificated Caviar Product
Abstrak: Fikosianin merupakan pigmen alami berwarna biru cerah yang kaya manfaat dengan kandungan antioksidan yang tinggi. Antioksidan memiliki peran yang sangat penting untuk mencegah kerusakan tubuh pada level molekuler yang disebabkan oleh radikal bebas. Radikal bebas dapat mengakibatkan kerusakan DNA, pembelahan sel abnormal (kanker), penuaan dini, inflamasi, penyakit jantung, dan beragam efek negatif lainnya. Pigmen fikosianin tersedia secara melimpah pada Spirulina platensis yang merupakan ganggang hijau biru (mikroalga) yang mudah dikultivasi dan dikondisikan serta dapat tersedia sepanjang tahun. Sebagai pigmen alami, fikosianin cenderung tidak stabil terpapar oksigen, cahaya, suhu, dan pH tertentu. Pemanfaatan pigmen fikosianin harus mampu menjaga kestabilan kandungan bioaktif pigmen dan tetap menarik bagi konsumen. Pengolahan pigmen fikosianin sebagai food additive pewarna pada produk spherificated caviar dapat dilakukan. Spherificated caviar dibuat dengan teknik spherification yang berfungsi sebagai penyalut yang melindungi bahan inti. Tujuan dari penelitian yaitu mempelajari pengaruh penambahan pigmen fikosianin kedalam produk spherificated caviar terhadap stabilitas kandungan antioksidan pigmen serta penerimaan konsumen terhadap produk. Metode yang dilakukan meliputi ekstraksi pigmen fikosianin dengan metode maserasi, kemurnian pigmen, analisis aktivitas antioksidan, dan uji organoleptik. Hasil menunjukan ekstrak pigmen dalam jangkauan warna biru kehijauan, pemurnian ekstrak menghasilkan angka 1,541 dengan kategori food grade. Analisis antioksidan menghasilkan nilai IC50 2,81 untuk ekstrak, dan nilai IC50 10,54 setelah diolah menjadi produk, keduanya termasuk kedalam kategori antioksidan kuat. Variasi konsentrasi pigmen fikosianin tidak memberi perbedaan nyata terhadap penerimaan konsumen dalam atribut warna, rasa, dan tekstur produk. Kata kunci: antioksidan, fikosianin, pigmen, spherificated caviar, Spirulina platensis, Phycocyanin is a bright blue natural pigment that has great beneficial and rich in antioxidant content. Antioxidant has an important role in preventing molecular damage on the body that is caused by free radicals. Free radicals could cause DNA damage, abnormal cell growth (cancer), premature aging, inflammation, heart diseases, and other negative effects. Phycocyanin pigment is found abundance in Spirulina platensis which is a blue green algae (microalgae) that is easy to cultivated and conditioned, also able to produce throughout the year. As a natural pigment, phycocyanin is prone to be unstable when exposed to oxygen, light, and to a certain temperature and pH. The utilization of phycocyanin pigment as colorant food additive in spherificated caviar product could be considered. Spherificated caviar is made with spherification technique that acts as coat / encapsulating that protects the main substance. The objective of this research is to study the effect of adding phycocyanin pigment into spherificated caviar product and also consumer preference of the product. Methods that are used including phycocyanin extractions with maceration method, phycocyanin pigment purity ratio, antioxidant activity analysis, and organoleptic test. The result shows phycocyanin pigment extraction produce bluish green colour, phycocyanin purification resulting in 1,541 value which belongs in the food grade category. Antioxidant analysis resulting in IC50 value of 2, 81 for phycocyanin extract, and IC50 value of 10,54 after being processed into spherificated caviar product, both value fall under very strong antioxidant category. Variants of phycocyanin pigment concentration added into the product did not affect consumer preferences in color, taste, and texture of the product. Keywords: antioxidant, phycocyanin, pigment, spherificate caviar, Spirulina platensis
Keyword: antioxidant, phycocyanin, pigment, spherificated caviar, spirulina platensis