Judul: House Dryer Design and Use of Sulfite Compounds for  Tapioca Quality Improvement at CV. Tani Sadulur Bogor
Abstrak: CV. Tani Sadulur Bogor merupakan industri penghasil tapioka skala kecil dimana proses produksi masih dilakukan secara sederhana. Tujuan penelitian ini yaitu mengetahui karakteristik mutu tapioka serta memberikan usulan perbaikan untuk peningkatan mutu tapioka. Tahapan penelitian yang dilakukan yaitu mempelajari standar kualitas tapioka, analisis penurunan mutu, analisis penyebab penurunan mutu, dan perbaikan. Berdasarkan uji karakteristik mutu tapioka diperoleh hasil parameter tapioka yang tidak sesuai dengan standar yaitu kadar air (18,80%), kadar lemak (2,53%), serat kasar (11,2%), derajat putih (77,83%), tingkat kehalusan (90%), dan residu sulfit (1.360 mg/kg). Oleh karena itu perlu dilakukan perbaikan untuk meningkatkan kualitas tapioka seperti penggunaan sulfit sebagai pemutih tapioka dengan konsentrasi 0,2%; serta pembuatan rumah pengering tertutup yang efektif dan efisien untuk solusi permasalahan proses pengeringan. Penambahan 0,2% senyawa sulfit menghasilkan derajat putih 96,2%. Adanya perbaikan rumah pengering dapat mengurangi waktu pengeringan selama 25 jam. Biaya investasi pembuatan rumah pengeringan sebesar Rp35.046.750. Penelitian ini juga perlu dilakukan penelitian lebih lanjut, misalnya dengan penambahan sensor humiditi yang akan mengontrol kondisi RH rumah pengering serta menggunakan panel surya dan pemanas infra merah sehingga ketika produksi meningkat maka pengeringan juga dapat dilakukan di malam hari., CV. Tani Sadulur Bogor is a small-scale tapioca-producing industry where the production process is still simple. The purpose of this study is to determine the quality characteristics of tapioca and provide suggestions for improvements to improve the quality of tapioca. The stages of research carried out are studying tapioca quality standards, analysis of quality degradation, analysis of causes of quality decline, and improvement. Based on the quality characteristic test of tapioca, the results of tapioca parameters that were not in accordance with the standards are moisture content (18.80%), fat content (2.53%), crude fiber (11.2%), whiteness (77.83%), thinness (90%), and sulfite residue (1,360 mg/kg). Therefore, it is necessary to make improvements to improve product quality, such as the use of sulfite as a tapioca bleach with a concentration of 0.2%; as well as the manufacture of an effective and efficient closed drying house to solve the problems of the drying process. The addition of 0.2% sulfite compound resulted in 96.2% whiteness. The improvement of the dryer housing can reduce the drying time by 25 hours. The investment cost for making houses dryer are Rp35,046,750. This research also needs to be done further research, for example by adding a humidity sensor that will control the RH condition of the dryer house and using solar panels and infrared heaters so that when production increases, drying can also be done at night.
Keyword: house dryer, quality, sulfite, tapioca

Judul: Perbaikan Proses Produksi Pati Sagu dengan Desain Rumah  Pengering
Abstrak: Unit pengolahan sagu di Tanah Baru - Bogor merupakan rumah produksi yang menghasilkan pati sagu dengan skala kecil. Proses pengeringan pati sagu masih dilakukan secara sederhana yaitu dengan menghamparkan tampah-tampah berisi pati sagu basah dibawah panas matahari langsung. Cara pengeringan seperti ini dianggap kurang efektif karena pati sagu yang dihasilkan berada dibawah standar mutu yang ditetapkan, antara lain: kehalusan lolos ayakan yang kurang dari 95%, waktu pengeringan yang lama hingga 2-3 hari dalam satu siklus produksi, banyak kontaminasi benda asing serta kadar air yang tinggi sekitar 18,22% sehingga mudah terserang mikroorganisme. Metode yang digunakan adalah Human Centered Design (HCD) yang terdiri dari identifikasi masalah, verifikasi masalah, ideasi, pembuatan prototipe dan verifikasi solusi. Ide solusi yang ditawarkan untuk permasalahan pada penelitian ini adalah perbaikan unit pengolahan sagu dengan menekankan pada proses pengeringannya berupa pembuatan desain rumah pengering yang efektif dan efisien dengan mempertimbangkan kemampuan unit pengolahan sagu dalam mengimplementasikannya., The sago processing unit in Tanah Baru - Bogor is a small scale production house where the sago starch has been produced. The drying process of sago starch was still carried out conventionally by spreading tampah that contain wet sago starch under the direct sunlight. This drying method was considered as less effective way since the quality of sago starch produced has below the applied standard for instance as fineness of passing sieve which less than 95%, overlong drying time which up to 2-3 days in one cycle production, high contamination of impurities, and high water content around 18.22% so that it is easily attacked by any microorganisms. The Human Centered Design (HCD) method has been used in this research which consists of problem identification, problem verification, ideation, prototyping, and solution verification. The suggested idea solution for the problem in this research was the improvement of sago processing unit by emphasizing the drying method in the form of designing an effective and efficient drying house by considering the ability of sago starch production house for the implementation.
Keyword: Human Centered Design, house dryer, sago starch

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