Judul: Sintesis para-Menthane-3,8-diol dari Fraksi Sitronelal Minyak Serai Wangi Sebagai Repelan Nyamuk
Abstrak: Tingginya prevalensi dan mortalitas kasus demam berdarah dengue di dunia menekankan penggalakan upaya penanganan maupun preventif, salah satunya penggunaan produk repelan nyamuk tetapi, diketahui bahwa senyawa aktif yang umumnya terdapat pada produk repelan nyamuk dapat menimbulkan beberapa efek samping. Alternatif senyawa aktif repelan nyamuk yang memiliki daya penolakan terhadap nyamuk lebih baik dibandingkan beberapa minyak atsiri dan efek samping minimal ialah para-Menthane-3,8-diol (PMD) yang dapat disintesis dari fraksi sitronelal minyak serai wangi menggunakan katalis berupa asam sulfat melalui reaksi siklisasi sitronelal menjadi PMD tetapi, selain menghasilkan senyawa PMD, senyawa lain bernama PMD sitronelal asetal juga akan terbentuk jika reaksi dibiarkan berlanjut. Pada penelitian ini dilakukan dalam 2 tahap yaitu tahap 1 berupa sintesis PMD, sementara tahap 2 berupa formulasi spray repelan nyamuk berbasis PMD. Tahap 1 penelitian dilakukan dengan menggunakan Rancangan Faktorial 23 dengan tambahan 5 percobaan pada titik pusat dengan 3 faktor yaitu suhu, konsentrasi asam sulfat, dan waktu sintesis. Parameter yang diteliti berupa kandungan PMD, kandungan PMD sitronelal asetal, persentase sitronelal terkonversi, dan persentase sitronelal dan isopulegol yang dikonversi menjadi PMD. Sementara itu, tahap 2 penelitian dilakukan dengan menggunakan Rancangan Acak Lengkap dengan faktor yang diteliti berupa variasi penambahan PMD. Spray repelan nyamuk yang dihasilkan kemudian dilakukan karakterisasi serta uji hedonik. Sintesis PMD yang dilakukan pada kondisi suhu 50˚C, konsentrasi asam sulfat 0,25%, dan waktu sintesis 8 jam menghasilkan produk dengan konsentrasi PMD yang terdeteksi sebesar 77,32%, PMD sitronelal asetal 12,61%, persentase sitronelal terkonversi 96,60%, serta persentase sitronelal dan isopulegol dikonversi menjadi PMD 95,97%. Sementara tahap validasi yang dilakukan pada suhu 50˚C, konsentrasi asam sulfat 0,25%, dan waktu sintesis 5 jam menghasilkan produk dengan konsentrasi PMD sebesar 55,37%, PMD sitronelal asetal 14,44%, sitronelal terkonversi 85,92%, serta sitronelal dan isopulegol dikonversi menjadi PMD sebesar 74,1%. Produk spray repelan nyamuk berbasis PMD yang paling disukai oleh panelis yaitu produk dengan penambahan 8 ml PMD atau kandungan PMD 8% yang memiliki karakteristik bobot jenis 1,0035 g/cm3, pH 9,44, didominasi oleh aroma serai wangi dan sedikit aroma herbal serta hangat, berbentuk cairan berwarna putih opaque yang cair dan licin ketika awal diaplikasikan, namun menimbulkan sedikit sensasi lengket beberapa saat setelah pengaplikasian.
Keyword: Citronellal fraction, citronella oil, mosquito repellent, para-Menthane- 3,8-diol

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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