To maintain the stability of nanofluid from precipitation and agglomeration, some methods such as ultrasonic vibration, adding surfactant, and controlling the pH value of the system have been studied. Herein, the preparation of titanium dioxide (TiO2)-water nanofluid, by using TiO2 nanoparticles (TiO2 NPs) and the cationic surfactant cetyltrimethylammonium bromide (CTAB), was investigated to determine the effects of the sequence method on the preparation of TiO2water nanofluid, its thermal conductivity, its stability, and its temperature distribution. NPs can improve the efficiency of heat transfer fluids and improving the stability of colloidal systems. Some parameters were varied, including sonication times of 5, 10, and 30 minutes, variations of TiO2 loading in 1-8% volumetric loading, concentrations of CTAB (0.005-0.035 wt%), and pH at 8-12. The procedure sequences of 2 and 5 showed the distribution particle size of TiO2 nanoparticles in nanofluid had a narrow range (190.3-208.7 nm) compared to other sequence methods (611 nm-5.35 m). The procedure sequence of 2 is following demineralized water (100 mL), 8% volumetric loading of TiO2 NPs, ultrasonication time of 10 min and CTAB of 3.2×10-3 M, while the procedure sequence of 5 is in the respective order of demineralized water (100 mL), 8% volumetric loading of TiO2 NPs, ultrasonication time of 10 min and pH at 8. The CTAB surfactant (0.029 wt%) had a greater influence on particle distribution in the nanofluid than the pH. The thermal conductivities of the nanofluid were characterized with TiO2 nanofluid as the working fluid. The experimental results showed a maximum of 21% thermal conductivity enhancement for 8% volumetric loading of TiO2 NPs at pH 8 and fourfold increase in critical micelle concentration (0.029 wt%) from CTAB. These findings offer the potential for preparing a stable TiO2-water nanofluid with a short ultrasonic time of 10 minutes. This process is a desirable and very useful to obtain a stable TiO2-water nanofluid with a short ultrasonic time for efficient process and low-cost nanofluid with high

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Indonesia is the largest sago feedstock in the world. There are about 2 millions ha sago forest that approximately half of the world's sago forest is present in Indonesia. Naturally, sago spreads widely in Papua, while semi-cultivation is in Maluku, Sulawesi, Borneo, and Sumatra. The species sago (Metroxylon sago) was used in this study. It has a relatively high starch content (95.99%) with low amylose content (20.61%) and low protein content (1.63%). Modified sago flour is a product from sago flour that modified with fermentation to increase the nutritional value of the sago flour. It can be used as a gluten free flour and low-calorie food products. The bacteria (Lactobacillus plantarum) was used in the fermentation. However, the color of the modified sago flour is off-white, if the fermentation time is too long. Therefore, it is necessary to investigate the effect of fermentation time and initial bacteria cells number on increasing nutritive value of sago flour. The variables used were fermentation times (12, 24, and 36 h) and initial bacteria cells number (7 x 1010, 7 x 1011, 1.05 x 1012, and 3,05 1012 cells of L. plantarum). The result showed that amylose and protein content increased from 20.61% to 33,06% and from 1.41% to 4.11%, respectively, with bacterial variables of 3,5 x 1012 and fermentation time of 36 h.

Dalam penelitian ini telah dilakukan perancangan pabrik Tepung singkong termodifikasi berbahan dasar singkong dengan kapasitas sebesar 300.000 Ton/tahun, waktu operasi 24 jam dan 300 hari/tahun. Tujuan perancangan pabrik Tepung singkong termodifikasi ini adalah untuk mensubstitusi kebutuhan tepung terigu Indonesia sehingga mampu menekan nilai impor tepung terigu. Pabrik Tepung singkong termodifikasi ini direncanakan akan didirikan di Kabupaten Wonogiri, Provinsi Jawa Tengah. Alasan pemilihan tempat ini adalah karena tersedianya sarana transportasi darat dan laut, ketersediaan listrik, air dan pemasaran produk dapat dilakukan di daerah sekitar pabrik dan luar pulau karena posisinya yang berada di tengah Indonesia. Proses yang digunakan dalam pabrik ini yaitu proses fermentasi dengan menggunakan bakteri Lactobacillus plantarum selama 5 hari untuk meningkatkan kadar protein tepung sehingga dapat mensubstitusi kandungan nutrisi dari tepung terigu itu sendiri. Proses dalam pabrik ini terdiri dari 3 tahap utama yaitu tahap persiapan bahan baku, tahap fermentasi, dan tahap penepungan. Sumber dana investasi berasal dari modal sendiri sebesar 60% biaya investasi dan modal pinjaman sebesar 40% biaya investasi dengan bunga sebesar 10,5% per tahun. Dari analisa perhitungan ekonomi didapat hasil investasi Rp 473.098.662.000 dengan IRR 44%, POT 2 tahun 3 bulan, dan BEP 17,82%

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