Judul: Penentuan Kondisi Proses Pemisahan Sitronelal dan Rhodinol dari Minyak Sereh Wangi dengan Distilasi Fraksinasi Vakum
Abstrak: Minyak sereh wangi merupakan salah satu minyak atsiri yang memiliki komponen utama sitronelal dan rhodinol. Komponen utama tersebut dapat dipisahkan dengan metode distilasi fraksinasi. Proses distilasi fraksinasi dengan alat dan kondisi proses berbeda berpengaruh terhadap proses pemisahan fraksi minyak sereh wangi. Oleh karena itu, perlu diketahui pengaruh suhu dan rasio refluks pada proses pemisahan sitronelal dan rhodinol minyak sereh wangi dari unit distilasi fraksinasi vakum kapasitas 7L yang telah di desain dengan spesifikasi tertentu. Proses pemisahan dilakukan pada tekanan 60 mmHg dengan umpan 5L dan dilanjutkan proses redistilasi fraksi kaya sitronelal dan rhodinol. Fraksi sitronelal dan rhodinol yang dihasilkan dilakukan analisis GC-MS untuk mengetahui konsentrasi masing-masing fraksi. Variasi refluks yang digunakan pada pemisahan sitronelal yaitu 12:4, 6:4, 6:2 dan 10:10. Suhu dan rasio refluks berpengaruh terhadap kemurnian fraksi. Kemurnian fraksi sitronelal tertinggi yang dihasilkan yaitu sebesar 50,55% dan fraksi rhodinol sebesar 37,09% pada rasio refluks 6:4. Proses redistilasi fraksi kaya sitronelal dan rhodinol menghasilkan konsentrasi senyawa sitronelal sebesar 42,72% dan senyawa rhodinol sebesar 32,51% dengan rasio refluks 10:10. Kemurnian sitronelal meningkat dan waktu proses lebih singkat dikarenakan pada suhu dan rasio refluks yang digunakan, alat bekerja lebih baik sehingga menghasilkan kemurnian lebih tinggi. Kata kunci: distilasi fraksinasi vakum, minyak sereh wangi, refluks, rhodinol, sitronelal, Citronella oil is one of the essential oils that has the main components of citronellal and rhodinol. The main components can be separated by fractional distillation method. Fractional distillation process with different tools and process conditions affect the separation process of citronella oil fraction. Therefore, it is necessary to know the effect of temperature and reflux ratio on the separation process of citronellal and rhodinol of citronella oil from a 7L capacity vacuum fractionation distillation unit which has been designed with certain specifications. The separation process was carried out at a pressure of 60 mmHg with 5L feed and continued with the redistillation process of the citronellal and rhodinol-rich fractions. The resulting citronellal and rhodinol fractions were analyzed by GC-MS to determine the concentration of each fraction. Reflux variations used in citronellal separation are 12:4, 6:4, 6:2 and 10:10. Temperature and reflux ratio affect the purity of the fraction. The highest purity of the citronellal fraction produced was 50.55% and the rhodinol fraction was 37.09% at a reflux ratio of 6:4. The redistillation process of citronellal and rhodinol-rich fractions resulted in a concentration of citronellal compounds of 42.72% and rhodinol compounds of 32.51% with a reflux ratio of 10:10. The purity of citronellal is increased and the processing time is shorter because at the temperature and reflux ratio used, the tool works better resulting in higher purity. Keywords: citronella oil, citronellal, rhodinol, reflux, vacuum fractional distillation
Keyword: distilasi fraksinasi vakum, minyak sereh wangi, refluks, rhodinol, sitronelal

Judul: Pemisahan Fraksi Kaya Sitronelal, Sitronelol, dan Geraniol Minyak Sereh Wangi Menggunakan Distilasi Fraksinasi Vakum
Abstrak: The main compounds of citronella oil are citronellal, citronellol, and geraniol, all of which determine the fragrance intensity and price of the citronella oil it self. Separation of those compounds increased the value of citronella oil. The aim of this research is to obtain the optimum amounts of citronellal, citronellol, and geraniol fractions by vacuum of fractional distillation technology. Conditioning process using 30:1 reflux ratio obtioned purer citronellal, citronellol, and geraniol than conditioning process with 10:1 reflux ratio. The separation process was held in 5 - 4 mBar vacuum pressure and the variation of reflux ratio 10:10, 20:10, 30:10. The optimum amounts of citronellal, citronellol, and geraniol was obtioned in the variation of reflux ratio 10:10, they are 90.670 % of 620 ml, 41.101 % of 160 ml, and 53.581 % of 500 ml respectively
Keyword: vacuum fractional distillation, geraniol, citronellol, citronellal, citronella oil

Judul: Construction of Strongly Optimal Binary Linear Code with Minimum Distance 9 and 11
Abstrak: A binary linear code of length n over q F is a subspace of n q F . A code has three parameters that attached to it, namely length, dimension, and minimum distance. A code with length n, dimension k and minimum distance d is often called [n, k, d ]-code. Usually, when two parameters are given, then we want to find a code that has the best value for the last parameter. Based on Gilbert- Varshamov bound, if a [n, k, d ]-code exists and can not be expanded, we call it a strongly optimal code. In this paper, we construct strongly optimal code with minimum distance 9 and 11. In constructing the code, we created a theorem and algorithm based on Gilbert-Varshamov bound before we implement the algorithm to MAPLE programming language. Because of computational limitations, the program can only construct up to k = 10 for d = 9 and k = 12 for d = 11.
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