Judul: Likuifikasi Onggok dan Konversinya Menjadi Ester Poliol Oleat sebagai Pengawabusa.
Abstrak: Onggok merupakan biomassa yang mengandung selulosa dan pati. Onggok dilikuifikasi dengan etilena glikol dalam suasana asam menghasilkan poliol. Poliol kemudian diesterifikasi dengan asam lemak dengan ragam nisbah massa poliol:asam lemak, yaitu 1:1, 1:2, 1:3, dan 1:4. Ester poliol dari onggok diuji efektivitasnya sebagai pengawabusa (defoamer). Likuifikasi onggok menghasilkan rendemen likuifikasi 91.65%, dan bilangan hidroksil 613.5 mg KOH/g. Spektrum inframerah onggok yang terlikuifikasi menunjukkan vibrasi ulur hidroksil pada bilangan gelombang 3288 cm-1. Setelah esterifikasi, tidak terdapat serapan inframerah untuk vibrasi gugus hidroksil dan terdapat pergeseran vibrasi karbonil menjadi 1738 cm-1 sehingga dapat disimpulkan poliol telah teresterifikasi. Ester poliol oleat dengan bilangan ester terbesar adalah pada nibah massa 1:1, yakni 206 mg KOH/g. Ester poliol oleat dengan efektivitas busa paling baik ialah pada nisbah massa 1:1 dan 1:3 dengan konsentrasi optimum masing-masing 3200 mg/L dan 4800 mg/L.
Keyword: asam oleat, esterifikasi, likuifikasi, onggok, poliol

Judul: Sintesis dan Pencirian Ester dari Asam Oleat dan Poliol Berbasis- Onggok
Abstrak: Onggok is a solid waste from tapioca industry that contains cellulose. Polyhydroxyl compounds (polyol) can be produced through liquefaction of cellulose. Cellulose liquefaction was carried out in ethylene glycol medium catalyzed by sulfuric acid, at 150 °C over 4 h, with 98.72% of yield. The polyol was esterified with oleic acid and sulfuric acid as catalyst to synthesize a nonionic surfactant. Esterification was carried out at 140 °C in 4 h, with oleic acid-polyol ratios of 1:2, 1:1, and 2:1. The free fatty acid contents and acid values of the esterification products were 23.07, 43.05, 60.97% and 32.67, 60.97, 86.34 mg KOH/g, respectively. Infrared spectrum of the ester products showed a C=O stretching band in wavenumber region of 1750–1715 cm-1, which was not present in polyol, but in oleic acid (1720–1680 cm-1). Intensity of O-H stretching band in ester products was weaker than in polyol spectrum (around 3400 cm-1) and C-H stretching band of the ester products in 2950–2800 cm-1 was originated from oleic acid.
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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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