Judul: Optimization of para-Menthane-3,8-diol Production Process From the Citronellal Fraction of Citronella Oil on a Pilot Scale
Abstrak: Senyawa para-Menthane-3,8-diol merupakan bahan aktif alami yang dapat menjadi pengganti bahan aktif sintetik DEET dalam produk anti nyamuk karena memiliki kemampuan mengusir nyamuk yang hampir sama. Tujuan dari penelitian ini ialah untuk mengetahui kondisi optimum dalam mensintesis PMD yang dilakukan dalam skala pilot, mengetahui perbedaan PMD yang dihasilkan dari bahan baku yang berbeda, mengetahui karakteristik PMD yang dihasilkan serta mengetahui stabilitas PMD tersebut. Proses sintesis PMD dilakukan dengan memanaskan campuran fraksi sitronelal dan katalis ??2????4 0,15% pada suhu 50? dan kecepatan pengadukan yang bervariasi (750 rpm, 1000 rpm dan 1250 rpm) selama 5 jam. Proses sintesis PMD menghasilkan kadar PMD sebesar 67,07%70,91%, tidak mengandung PMD sitronelal asetal, persentase konversi sitronelal sebesar 99,30%-99,60% dan selektivitas PMD sebesar 82,93%-85,11%. Sintesis PMD dengan bahan baku fraksi sitronelal dari fraksinasi laboratorium menghasilkan kadar PMD sebesar 32,13%-32,25%. PMD berbahan dasar fraksi sitronelal minyak serai wangi memiliki aroma seperti mentol dan berwarna jernih dengan nilai pH 5, nilai massa jenis rata-rata yaitu 0,970 g/cm, nilai indeks bias rata-rata yaitu 1,4641 dan rasio kelarutan yaitu 1:2 pada etanol 70% dan 1:1 pada etanol 90%. PMD bersifat stabil pada suhu ruang dan suhu 40? yang dilihat melalui sifat fisik, karakteristik, dan konsistensi kadar senyawa PMD yang terdapat didalamnya., Para-Menthane-3,8-diol (PMD) is a natural active ingredient that can serve as a substitute for the synthetic active ingredient DEET in mosquito repellent products, as it has almost the same ability to repel mosquitoes. The aim of this study is to determine the optimal conditions for synthesizing PMD on a pilot scale, to identify the differences in PMD produced from different raw materials, to characterize the produced PMD, and to determine its stability. The synthesis process of PMD is carried out by heating a mixture of citronellal fraction and 0,15% ??2????4 catalyst at a temperature of 50? with varying stirring speeds (750 rpm, 1000 rpm, and 1250 rpm) for 5 hours. The PMD synthesis process resulted in a PMD content of 67,07%-70,91%, no citronellal acetal PMD, a citronellal conversion percentage of 99,30%-99,60%, and a PMD selectivity of 82,93%85,11%. The synthesis of PMD using citronellal fraction from laboratory fractionation produced a PMD content of 32,13%-32,25%. PMD derived from citronellal fraction of lemongrass oil has a menthol-like aroma and is clear in color, with an average pH value of 5, an average density value of 0,970 g/cm, an average refractive index value of 1,4641, and a solubility ratio of 1:2 in 70% ethanol and 1:1 in 90% ethanol. PMD is stable at room temperature and at 40?, as evidenced by its physical properties, characteristics, and consistent PMD compound content.
Keyword: Optimization, Citronellal fraction, para-Menthane-3,8-diol, Synthesis

Judul: Synthesis of para-Menthane-3,8-diol  from Citronellal Fraction of Citronella Oil as Mosquito Repellent
Abstrak: The significant prevalence and mortality rate of dengue cases worldwide highlight the importance of promoting treatment and prevention measures, such as the utilization of mosquito repellents, but it is known that the active compounds commonly found in mosquito repellent can cause some side effects. A viable alternative compound for an effective mosquito repellent with less side effects is para-Menthane-3,8-diol (PMD). The production of PMD can be done by synthesizing the citronellal fraction of citronella oil using sulfuric acid as the catalyst through a cyclization of citronellal to PMD, but a by-product called PMD citronellal acetal will be formed if the reaction continues to proceed. This research was conducted in two phases. The first phase focused on the synthetization of PMD, then the formulation of PMD-based mosquito repellent spray. The first phase conducted The experimental design using a 23 Factorial Design with 3 factors, namely temperature, acid concentration, and synthesis duration, and 5 additional midpoint experiments. The observed parameters were PMD content, PMD citronellal acetal content, percentage of converted citronellal, and percentage of citronellal and isopulegol converted into PMD. The second phase was conducted using a Completely Randomized Design to investigate the effect of varied addition of PMD. The product was then characterized and evaluated through hedonic test. PMD synthesized at 50˚C and sulfuric acid concentration of 0,25% for 8 hours produced a product with PMD concentration of 77,32%, 12,61% PMD citronellal acetal, converted citronellal at 96,601%, and percentage of citronellal and isopulegol converted to PMD is 95,966%. While from the verification phase done at 50˚C and sulfuric acid concentration of 0,25% for 5 hours produced a product with PMD concentration of 55,37%, 14,44% PMD citronellal acetal, converted citronellal at 85,92%, and percentage of citronellal and isopulegol converted to PMD is 74,1%. Panelist particularly favored the mosquito repellent spray containing 8 ml or 8% PMD that had density of 1,0035 g/cm3, pH of 9,44, have strong aroma dominated by citronella with hints of herbaceous and warm notes, an opaque white liquid with watery consistency and slippery when applied but tended to get slightly sticky after a while.
Keyword: Fraksi sitronelal, minyak serai wangi, para-Menthane-3,8-diol, repelan  nyamuk

Judul: Implementation of Spatio-Temporal Change Query in Relational Database.
Abstrak: Geographic object changes in various views. Object changes are recorded using a model of static storage. No historical connection between old version data and new version data has been built. For that, a storage model of spatio-temporal queries that can analyze spatio-temporal changes has been developed. The object changes the geometry are grouped according to the taxonomy of Spatio-Temporal Pattern Change. This research has been able to apply the query patterns change including born, expand, merge, contract, split, normal and die. This query based on geometric (area) changes. The implementation of spatio-temporal change queries represents an object changes continuously with easy, change detection is done by comparing two versions of data. Keyword: spatio-temporal change query, spatio-temporal change pattern.
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