Judul: Improving the Quality of Coconut Cooking Oil in the  Koperasi W, Purworejo Regency
Abstrak: Koperasi W merupakan suatu unit usaha yang berbasis pengolahan kelapa menjadi produk turunannya. Permasalahan Koperasi W yaitu aroma dan warna minyak goreng kelapa yang kurang dapat diterima oleh konsumen. Minyak goreng kelapa tersebut diproduksi dengan metoda basah dari perasan santannya dan dimurnikan dengan tahapan pemanasan, netralisasi, pemucatan, penghilangan bau, dan penyaringan. Tujuan penelitian untuk meningkatkan mutu produk minyak goreng kelapa yang meliputi kadar air, asam lemak bebas, bilangan peroksida, aroma, dan warna minyak goreng kelapa yang kurang dapat diterima oleh konsumen produk minyak goreng kelapa Koperasi W. Metode yang digunakan untuk meningkat mutu minyak goreng kelapa yaitu dengan metode pemucatan menggunakan kombinasi arang aktif dan bentonit. Hasil perbaikan 1 yaitu kombinasi adsorben yang optimal adalah 5% bentonit: 5% arang aktif: 200g minyak. Rendemen skala pabrik yang diperoleh 82% dan hasil uji organoleptik untuk warna dan aroma sudah berbeda nyata. Uji mutu minyak yaitu kadar air 0,15%, FFA 1,09%, bilangan peroksida 8,88mek O2/kg, protein 1,9%, dan transmitan warna 94,5%. Perbaikan 2 minyak goreng diperoleh hasil rendemen 94%, kadar air 0,095%, FFA 0,2%, bilangan peroksida 2,4mek O2/kg, protein 0,5%, dan transmitan warna 98%. Pemucatan menggunakan kombinasi arang aktif dan bentonit dapat meningkatkan mutu minyak goreng kelapa, antara lain kadar air, asam lemak bebas, bilangan peroksida, warna, dan aroma minyak goreng kelapa. Kata kunci: adsorben, aroma, minyak goreng kelapa, mutu, warna., Koperasi W is a business unit based on coconut processing into its derivative products. The problem with Koperasi W is that the aroma and color of coconut cooking oil are not acceptable to consumers. Coconut cooking oil is produced by the wet method from the coconut milk and purified by heating, neutralization, blanching, deodorizing, and filtering. Research purposes to improve the quality of coconut cooking oil products which include water content, free fatty acids, peroxide number, aroma, and colour of coconut cooking oil which are less acceptable to consumers of the product Koperasi W. The method used to improve the quality of coconut cooking oil is the bleaching method using a combination of activated charcoal and bentonite. The result of improvement 1 is that the optimal adsorbent combination is 5% bentonite: 5% activated charcoal: 200g oil. The yield of factory scale obtained was 82% and the results of organoleptic tests for color and aroma were significantly different. Oil quality tests were 0.15% water content, 1.09% FFA, peroxide number 8.88 mekO2/kg, protein 1.9%, and color transmittance 94.5%. The repair of 2 cooking oils obtained yields of 94%, water content 0.095%, FFA 0.2%, peroxide number 2,4mekO2/kg, protein 0.5%, and color transmittance 98%. Bleaching using a combination of activated charcoal and bentonite can improve the quality of coconut cooking oil, including water content, free fatty acids, peroxide value, color, and aroma of coconut cooking oil.
Keyword: adsorbent, aroma, coconut cooking oil, quality, color

Judul: Reducing Residual Potassium Hydroxide Levels from Coconut Cooking Oil by Adding Baffles to the Washing Equipment at Koperasi W
Abstrak: Minyak klentik kelapa merupakan minyak kelapa yang diolah secara sederhana, sehingga memiliki kandungan asam lemak bebas tinggi yang dapat merusak kualitas minyak. Terlebih jika terdapat zat yang bersifat katalis terhadap reaksi hidrolisis pada minyak seperti KOH. Efektivitas proses pencucian minyak menjadi faktor penting dalam menurunkan kadar KOH yang dapat menjadi katalisator dalam minyak. Penelitian ini bertujuan mengetahui desain alat pencucian yang dapat meningkatkan efektivitas proses pencucian minyak guna menurunkan kadar KOH dalam minyak. Untuk itu, dilakukan modifikasi alat pencucian dengan penambahan baffle untuk meningkatkan tumbukan antar komponen dalam minyak guna memindahkan komponen KOH ke dalam air. Hasil modifikasi alat pencucian menunjukkan bahwa penambahan baffle dapat menurunkan kadar KOH dalam minyak yang ditunjukkan dengan kadar asam lemak bebas melalui bilangan asam yang lebih rendah dibandingkan dengan tanpa baffle. Selain mempengaruhi kualitas produk yang menjadi lebih baik, modifikasi alat juga mempengaruhi harga pokok produksi serta harga jual produk yang meningkat dan dapat membantu koperasi untuk lebih berkembang., Coconut clectic oil is coconut oil that is processed in a simple way, so it has a high free fatty acid content that could damage the quality of the oil. Especially if there is a substance that is a catalyst for hydrolysis reaction in oil such as KOH. The effectiveness of the oil washing process is an important factor in reducing KOH levels which can be a catalyst in oil. This research aims to determine the design of the washing machine that can increase the effectiveness of the oil washing process to reduce KOH levels in the oil. For this reason, a modification of the washing machine was carried out with the addition of baffle to increase collisions between components in oil to move KOH components into water. The results of the modification of the washing machine show that the addition of baffle can lower the KOH level in the oil shown with the free fatty acid level through a lower number of acids compared to without baffle. In addition to affecting product quality for the better, tool modifications also affect the cost of production and product selling prices which increase and can help cooperative to develop more.
Keyword: baffle, coconut cooking oil, cost of production, free fatty acids

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