Synthetic membranes have gained an important place in chemical technology and are used in a broad range of applications. UV irradiation is an age old process used for disinfection as well as for sterilization purposes. It is used for sterilizing equipment in which polysulfone (PSf) membranes are used. As a result, short time UV irradiation of polymer membranes has acquired importance in recent times. In the present study, microporous polysulfone membranes with 0.108 mm thickness have been prepared using phase inversion method. Effect of UV irradiation on the membranes for short time intervals (0 -60 minutes) has been investigated using UV-Vis and FTIR spectrophotometer, and SEM. The performance of the membranes has studied by filtration techniques. UV-Vis and IR spectra analysis and SEM images obtained suggest that chains scission and crosslink have occurred simultaneously in the irradiated membranes by UV radiation in a dose dependant manner. The pure water flux (PWF) values of irradiated membranes obtained from filtration studies were higher compared to that of the control membrane. These results show that a very short UV irradiation (2 minutes) affected the physicochemical characteristics of microporous polysulfone membrane which it increases with increase in time.
BIOSINTESIS NANOPARTIKEL PERAK MENGGUNAKAN EKSTRAK DAUN SAMBILOTO: OPTIMASI PROSES DAN KARAKTERISASI. Pada penelitian ini telah berhasil disintesis nanopartikel perak (AgNP) dengan metode biologi (biosintesis). Sintesis dilakukan dengan menggunakan ekstrak daun Sambiloto (Andrographis paniculata Ness). Penelitian ini meliputi penentuan rasio volume sintesis (larutan AgNO 3 :larutan ekstrak) yang optimum dan karakterisasi nanopartikel perak yang terbentuk. Konsentrasi larutan AgNO 3 yang digunakan 1 M dan larutan ekstrak adalah 7,5 g/L. Karakterisasi meliputi spektrofotometer UV-Vis, EDS, TEM, XRD dan FT-IR. Hasil penelitian menunjukkan bahwa rasio volume sintesis optimum adalah 10 µL:10 mL. Karakteristik nanopartikel perak yang diperoleh adalah absorbsi Surface Plasmon Resonance (SPR) pada panjang gelombang 423 nm. Puncak-puncak difraksi teramati pada sudut 2 yaitu 38,18 0 , 45,81 0 dan 64,87 0 , yang bersesuaian dengan bidang hkl (1 1 1), (2 0 0) dan (2 2 0). Data tersebut menunjukkan bahwa nanopartikel perak yang terbentuk memiliki struktur kristal Fface Centre Cubic (FCC) dengan parameter kisi a sebesar 4,03 Å. Hasil karakterisasi dengan TEM diperoleh ukuran partikel sekitar 10-30 nm.
Snake fruit (salacca zalacca) characterization for Dye Sensitized Solar Cell (DSSC) material was conducted using Fourier transform Infrared (FTIR) and Principle Component Analysis (PCA) method. Dragon fruit and mangos teen were used as validator since they are containing anthocyanin. Data shows that snake fruit and mangos teen are in one cluster. Therefore, snake fruit can be used as DSSC material. DSSC fabrication using sandwich method that contains counter electrode, electrolyte and working electrode. The working electrode was made of thin film of titanium dioxide (TiO2) into indium Tin Oxide (ITO) which then was soaked in dye snake fruit as time function of 6, 12 and 24 hours. Result showed that the longer time of soaking, the current and efficient increased. In twenty four hours soaking, the current, voltage and efficiency were 6 mA, 9.16 V and 0.011 % respectively.
A CCTV optimization system has been designed using PIR (passive infrared) sensor based on AT89S52 microcontroller. This device consists of several series of sensor circuit, AT89S52 microcontroller minimum system, stepper motor driver circuit, push-on circuit and alarm circuit. The working system of the room safety device is when the PIR (passive infrared) sensor detects the movement of the object, then the output of the sensor is forwarded to the microcontroller, the microcontroller will process and convey to the driver circuit to drive the stepper motors that moves the CCTV. The push-on circuit is connected to the microcontroller port for controlling the movement of the stepper motor so it won’t rotate beyond 180 degrees, and for the safety of the room, an alarm circuit is connected to the microcontroller port as an alarming sound generator.
The research of determination of the oxide mineral contents of the Tegal Lenga Beach iron sand by using XRD has been done. Iron sand samples were taken from the top layer of the Tegal Lenga Beach sand. The three sand samples were taken from three different places which were separated at a distance of 15 m one another. The separation process is carried out using magnetic separation method. The characterization methods include mass fraction and X-ray diffraction (XRD). It obtained that the average mass fraction of the Tegal Lenga Beach iron sand is 54.71%. The minerals oxide contained are magnesium diiron (III) oxide (Mg Fe2 O4 and iron iron (III) titanium aluminum magnesium vanadium manganese silicon oxide (Fe4.42 Fe5.245 Ti4.72 Al0.7 Mg0.4 Cr0.3 V0.15) (Fe7.82 Mn0.114Si0.06) O32). The main oxide mineral compound is Magnesioferrite (MgFe2O4) oxide mineral of 51.34%. Abstract -Penelitian penentuan kandungan mineral oksida pasir besi Pantai Tegal Lenga dengan menggunakan XRD telah dilakukan. Sampel pasir besi diambil dari lapisan atas pasir Pantai TegalLenga. Tiga sampel pasir diambil dari tiga tempat berbeda yang dipisahkan pada jarak 15 m satu sama lain. Proses pemisahan dilakukan dengan menggunakan metode pemisahan magnetik. Metode karakterisasi meliputi fraksi massa dan difraksi sinar-X (XRD). Diperoleh bahwa fraksi massa rata-rata pasir besi Pantai Tegal Lenga adalah 54,71%. Mineral oksida yang terkandung adalah magnesium diiron (III) oksida (Mg Fe2 O4) dan besi besi (III) titanium aluminium magnesium vanadium silikon oksida mangan (Fe4.42 Fe5.245 Ti4.72 Al0.7 Mg0.4 Cr0.3 V0.15) (Fe7.82 Mn0.114Si0.06) O32). Senyawa mineral oksida utama adalah mineral oksida Magnesioferrite (MgFe2O4) yaitu 51.34%.Kata kunci: Mineral oxide, pasir besi Pantai Tegal Lenga, X-ray diffraction (XRD)
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