Judul: Aplikasi Sitronelal Minyak Sereh Wangi pada Produk Eau de Toilette dengan Bahan Pewangi Alami
Abstrak: The increasing awareness for customer’s health, lifestyle, and environmental issues leads them to purchase products that have natural advantages, and one of those is natural fragrance. The purpose of this study is to formulate eau de toilette with natural fragrance using citronellal from citronella oil and other essential oils. Preliminary research was done by survey method to identify trends in perfume using and essential oil types preferred by customers. Primary research was done by formulating eau de toilette at 7.4% fragrance concentration. In this research, the hedonic test utilizes preference for clarity, natural fragrance, and overall fragrance product parameters. The formulation is a mixture of fragrances to 10 ml ethanol as a solvent. Based on hedonic test and selection of the best formulas using Bayes method, three formulas were selected with the highest score. The best formula is mixed between 0.3 ml patchouli oil, 0.2 ml jasmine oil, and 0.3 ml lemon oil. The second formula is mixed between 0.3 ml patchouli oil, 0.2 ml jasmine oil, 0.1 ml citronellal, and 0.2 ml lemon oil. The third formula is mixed between 0.3 ml patchouli oil, 0.2 ml jasmine oil, 0.1 ml citronellal, and 0.2 ml peppermint oil. The best three formulas have flower and fresh aroma.
Keyword: natural fragrance, essential oils, eau de toilette, citronellal

Judul: Application of essential oils in  insect repellent air freshner gel
Abstrak: Citronella and lavender oils are known as insect repellent. Composition of insect repellent, combined with aromatic fragrance, such as lemon, kaffir lime, and ylang-ylang oils were packed in an air freshner gel with the addition of patchouli oil as fixative agent. The purposes of this study are (1) to get the best concentration of patchouli oil as fixative agent; (2) to get the best composition of insect repellent active ingredients and fragrance materials, and (3) to know the resistance and the loss on fragrance odor in air freshner gel during use (fourteen days). The methods used are sensory test with skoring test, effectiveness test of the air freshner gel for repelling mosquito, and hedonic test. Then, the last methods used are sensory test and weighing. The research result show that the best concentration of patchouli oil as fixative agent is 1% patchouli oil. The next results, there are three best compositions of essential oils in air freshner gel formula that effectively repell insects. The first formula composition consist fragrance ingredient (lemon oil 2%) and the active ingredient of insect repellent (citronella oil 2% and lavender oil 2%). The second formula composition comprises fragrance material (kaffir lime oil 2%) and the active ingredient of insect repellent (citronella oil 3%). The third formula composition consisting of fragrance material (ylang-ylang oil 2%) and the active ingredient of insect repellent (citronella oil 2% and lavender oil 2%). Based on the result of hedonic test, the most preffered fragrance from the three formulas is formula with lemon fragrance. The last results, the resistance on fragrance odor can be estimated that is still acceptable until eight days of use and the loss on fragrance odor during use (fourteen days) can be estimated 54.89% (0.988 gram).
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Judul: Cycle Hamilton pada Graf Lengkap, Graf Regular, dan Graf 2-Connected 4-Regular Berorder Kurang dari Sepuluh.
Abstrak: Suatu graf disebut graf Hamilton apabila graf tersebut memuat cycle Hamilton, yaitu cycle yang melewati setiap vertex tepat satu kali. Menentukan keberadaan cycle Hamilton pada suatu graf dapat menggunakan syarat cukup yang berupa teorema-teorema yang telah diperkenalkan sejak tahun 1950-an. Beberapa syarat cukup yang dibahas dalam karya ilmiah ini adalah syarat cukup yang berhubungan dengan graf lengkap dan graf regular. ,,,
Keyword: graf Hamilton, graf regular, graf lengkap, graf 2-connected 4-regular.