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"Biosurfactant are microbially produced compounds that can reduce surface tension and interfacial tension of the aqueous system. Biosurfactant can be applied in various industrial and environmental uses as emulsifier, deterjency and oil recovery. Biosurfactant can be produced from various substrates of cassava flour wastewater, sugar and crude oil spills etcetera..."

"ABSTRACTThe decrease in oil production is caused by the ageing of oil production wells. The enhanced oil recovery (EOR) technology is proven to increase oil reserves and production in mature oil fields. One EOR technology that has proven to be efficient in increasing oil production is microbial EOR by using biosurfactant. The most effective biosurfactant is rhamnolipid produced by Pseudomonas aeruginosa, the bacteria of which can lower the interfacial tension between the petroleum and water. In biosurfactant's production thanks to these bacteria, the substrate as the source of carbon in the fermentation process is needed. The sources of carbon used in this study are glucose, glycerol, molasses,banana peels, and waste cooking oil. This research aims to determine the most optimum carbon sources to produce biosurfactant from Pseudomonas aeruginosa by using Busnell Hass medium as a liquid medium of bacterial growth. Biosurfactant's production result are: 74mb/L from glucose; 63mg/L from banana peels; 66mg/L from glycerol; 85mg/L from waste cooking oil; and 64mg/L of molasses with the following decreasing surface tension: 33.55 mN/m from glucose; 32.51 mN/m from banana peels; 27.55 mN/m from glycerol; 22.46 mN/m from waste cooking oil; and 31.49 mN/m from molasses are as follows: 15.2 mN/m; 13.78 mN/m; 8:15 mN/m; 0.14 mN/m; and 11.2 mN/m respectively."

"ABSTRAKThe sessile drop method was implemented to calculate the values of the surface tension coefficient of liquid metals. Appropriate software was developed to increase the data processing efficiency and the accuracy of the obtained results. This paper provides information on the structure and applications of the designed programs as well as the underlying mathematical models used during computations. Since the determination of the surface tension coefficient in this study is based on the recognition of drop outlines from a digital image, the problems of calibration and appropriate photography mode adjustments are mentioned in this paper. In addition,the methods of controlling there search equipment using Arduino shields are described. Finally, the research results are presented in the form of graphs which show the temperature dependence of the studied parameters of metallic samples and compared with the literature data. "

"Karakteristik perpindahan panas yang dihasilkan oleh slaging akan sangat mempengaruhi heat exchanger tube boiler Unit 5 PLTU Suralaya, dengan melihat grafik konduktifitas thermal slaging serta material properties yang dihasilkan pada penelitian ini, maka dapat dilihat karakteristik thermal material slaging tersebut dan korosinya. Sebagai pelengkap, dibahas pula, proses terjadinya slaging pada PLTU Suralaya dengan referensi Studi Coal Wide Range PT Indonesia Power dan penelitian material tersebut. Dari penelitian diadapatkan bentuk fasa amorphous dan krital, dimana fasa kristal mayor adalah Mullite dan Pyrite. Senyawa MgO, SO3 dan Na2O sedikit sekali dijumpai pada slaging sampel dan tidak dijumpai adanya P2O5. Surface tension slaging bagian atas adalah 390,13 dyne/cm, sedang nilai konduktifitas thermal rata-rata adalah 43,346 W/m ºC dengan kecepatan rambat panas sebesar 1,474. 10-5 m/detik. Heat spesifik slaging rata-rata adalah 0,283 cal / gm °C pada suhu kurang dari 1350 °C dan 0,280 cal / gm °C pada suhu sama dengan 1350 ºC. Nilai perambatan kalor perluasan adalah sebesar 52.103 W/m2.Ditemukan pula “Island of Pyrite“ dengan diameter antara 500-2000µm untuk lapisan terluar (top) dan 490-1000µm untuk lapisan dalam (bottom). Proses korosi yang disebabkan oleh slaging merupakan korosi sumuran dan erosi, dengan agen korosi adalah campuran alkali pyrosulfate.......Characteristic of heat transfer as resulted by slaging will affects de-structurally the heat exchanger tube boiler of Unit 5 PLTU Suralaya. In this research, thermal characteristic of slaging materials and its corrosion behavior were evaluated subject to determination of thermal conductivity and property, in addition, formation process of slaging at PLTU Suralaya is discussed base on the study of coal wide range PT Indonesia Power. In slaging materials, it's found amorphous phase and crystal phase, where phase of major crystal are Mullite and Pyrite. MgO, SO3 and Na2O a few consisted in slaging and isn’t found existence of P2O5. Upper part of slaging, surface tension is 390,13 dyne/cm, and the thermal conductivity is 43,346 W/M º C, with heat speed is 1,474. 10-5 m/sec. Mean of specific heat is 0,283 cal / gm °C at temperature less than 1350 ° C and 0,280 cal / gm ° C at temperature is equal or more than 1350 º C. Radiation properties of slaging is 52. 103 W/m2. From SEM experience, its found “Island Of Pyrite" with diameter between 500-2000µm from upper part of slaging and 490-1000µm from bottom part of slaging. The corrosion process, its cause by mechanism of pitting corrosion and erosion, with agent of korosi is alkali pyrosulfate complex."

"Serat tandan kosong kelapa sawit (TKKS) merupakan limbah tanaman kelapa sawit yang berlimpah di Indonesia. Serat ini merupakan serat alam yang dapat digunakan sebagai penguat di dalam komposit polimer, namun masalah utama dari serat alam adalah hidrofilik sedangkan polimer propilena sebagai matriks adalah hidrofobik. Perlakuan kimia alkalinisasi merupakan perlakuan kimia yang dapat meningkatkan kompatibilitas serat dan sifat mekanis yang dihasilkan pada pembentukan komposit. Metode pengujian yang dilakukan untuk mengetahui bentuk serat di dalam struktur komposit menggunakan Scanning Electron Microscope (SEM) dan kemudian diolah menggunakan perangkat lunak ImageJ. Alkalinisasi dapat meningkatkan distribusi serat di dalam komposit dinyatakan dalam bentuk rasio distribusi hingga 0,42 pada serat 50 mesh dan 0,40 pada serat 100 mesh. Selain itu, kompatibilitas serat juga meningkat ditunjukkan oleh selisih tegangan permukaan yang menurun hingga 1.60 mN/m. Hasil pengujian dibentuk dalam purwa-rupa aplikasi sebagai contoh manfaat mengetahui pengaruh secara kuantitatif yaitu dapat memprediksi sifat-sifat yang dihasilkan.......Oil Palm Empty Fruit Bunch (OPEFB) Fiber is an abundant waste in Indonesia. This fiber is a natural fiber that can be used for reinforcement in polymer-based composites, but natural fiber is hydrophilic while polypropylene as a matrix are hydrophobic. Alkalinization is a type of chemical treatment that can improve fiber compatibility and mechanical properties resulting in the formation of composites. Testing methods conducted to determine the shape of the fibers in the composite structure are using Scanning Electron Microscope (SEM) and then processed using ImageJ software. Alkalinization can increase fiber distribution in composites expressed in the form of distribution ratio up to 0,42 for 50 mesh and 0,40 for 100 mesh. In addition, the compatibility of the fiber also increases, indicated by the differences in surface tension decreased to 1,60 mN/m. The test results are formed in the prototype of application that can be used for an example of the benefits of knowing the influence quantitatively so that can be able to predict the resulting properties.

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