Influence of Applied Potential on The Structural and Optical Properties of Cu2O Thin Films Grown by Electrochemical Deposition

Cu2O thin films have been deposited on indium-tin-oxide (ITO) coated glass substrate by electrochemical method or electrodeposition. The effect of deposition potential on the microstructure and optical properties of Cu2O thin films was studied. Electrodeposition for two Cu2O thin films was carried out at –0.5V and –0.6V relative to the standard calomel electrode (SCE) as a reference electrode. Cu2O thin films were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and UV-Visible spectroscopy. The diffraction pattern indicated the cubic structure of the Cu2O crystal has been well grown. The lattice parameters of Cu2O films slightly increased as the potential of electrodeposition increased. The crystallite size of Cu2O films significantly increased as the applied potential increased. Cu2O thin films showed a smooth and flat surface morphology based on SEM images. The optical transmittance of the Cu2O thin films drastically decreased as the applied potential increased due to the film thickness increasing. The bandgap energy of Cu2O films based on the Tauc plot increased as the applied potential increased, that is 2.0 eV for the film deposited at -0.5V and 2.13 eV deposited at -0.6V

SINTESIS DAN SIFAT MEKANIK BIOKOMPOSIT SERAT HELICONIA-POLIESTER

In this study, polyester-fiber heliconia biocomposites has been created and tested on its mechanical properties. Biocomposites was manufactured begins by separating the fibers.  it  consists  of  three  stages,  namely  chlorization,  alkaline  leaching  and extraction.  After  that,  the  manufacture  of  composites  made  with  Hand  Lay-up techniques.  Three  samples  with  variations in  fiber content,  ie without  the addition of fiber,  0.54  g  and  2.08  g  fiber.  Characterization  of  samples  includes  tensile  test, hardness,  and  impact.  The test results known that  the  tensile  strength  and  hardness increased  with  increasing  the  amount  of fiber  heliconia.  Impact  test  shows  sample values optimum working temperature is 10°

Synthesis and Characterization of Hydroxyapatite from Green Mussel Shell with Sol-Gel Method

Hydroxyapatite (HAp) is a major component of bones and teeth. HAp is widely used to repair, fill, extend, and reconstruct damaged bone tissue. HAp is used for bone and dental implants, so it is necessary to synthesize HAp. HAp synthesis can utilize green mussel shell waste as a calcium precursor. This research synthesized HAp from a green mussel shell using the sol-gel method. The controlled synthesis parameter was pH, and the variable being compared was the heating temperature at 900 and 1100 °C. The HAp products were characterized by an X-ray diffractometer (XRD), Fourier-transform infrared spectrophotometer, and scanning electron microscope. The results showed that HAp was formed at alkaline pH, namely at pH 11. The XRD pattern showed that Hap was formed along with type A apatite carbonate, octacalcium phosphate, α- and β-tricalcium phosphate. The crystallinity was increased by raising the temperature and prolonging the heating time. The quality of HAp will improve with increasing crystallinity, and increasing the temperature will also raise the amount of HAp formed

KARAKTERISTIK SIFAT OPTIK NANOPARTIKEL KARBON (CARBON DOTS) DENGAN METODE UV-VIS DRS (ULTRAVIOLET-VISIBLE DIFFUSE REFLECTANCE SPECTROSCOPY)

Research on the synthesis of Carbon Dots using the laser ablation method has been carried out at a time duration of 1, 2, and 3 hours (energy 60 mJ, wavelength 1064 nm and frequency 10 Hz). This research uses organic material from Tea and Toluene as the carbon solvent. The characterization method uses a UV-Vis Diffuse Reflectance Spectroscopy (UV-Vis DRS) spectrum to measure the reflectance value and uses the Kubelka-Munk equation to determine the relationship between the absorbance coefficient parameter (s) and the scattering reflectance coefficient (k). The size and morphological characterization methods used Particle Size Analyzer (PSA) and Transmission Electron Microscopy, while the functional group characteristics used the Fourier Transform InfraRed (FTIR) tool. FTIR spectra show the O-H group which is a hydroxyl bond and N-H is a carboxylic acid. The results of measurement and analysis of bandgap energy at different time durations for direct transition (n=2) were 1 hour (3.62 eV, 342.49 nm), 2 hours (3.24 eV, 380.61 nm) and 3 hours (2.74, 451.82 nm). Indirect transitions (n=1/2) were 1 hour (3.17 eV, 391.02 nm), 2 hours (2.50 eV, 495.36 nm) and 3 hours (2.21 eV, 559.04). &nbsp

Dye-sensitized Solar Cell Based on Flower-like ZnO Nanoparticles as Photoanode and Natural Dye as Photosensitizer

In this paper was reported the fabrication of dye-sensitized solar cell utilizing flower-like ZnO nanoparticle as photoanode and natural dye (anthocyanin) extracted from Lampeni (Ardisia humilis Vahl) fruit as photosensitizer. Anthocyanin dye extracted from Lampeni (Ardisia humilis Vahl) fruit shows a wide range of absorption spectra covering from 400 nm to 600 nm, which suitable for application as sensitizer in dye-sensitized solar cell. Flower-like ZnO was synthesized by precipitation method from mixed solution of zinc acetate dihydrate and KOH. X-ray diffraction analysis of ZnO was found a hexagonal structure with lattice parameters a = b = 3.25 Ǻ and c = 5.21 Ǻ, while average crystal size (ACS) was found 23.403 nm. The observation by SEM shows a flower-like structure arranged from ZnO nanorods. Optical absorption spectra of ZnO shows a strong absorption under 350 nm, and sharp absorption transition occurs around 350 nm from which the bandgap energy of ZnO was determined. Using Tauc plot method, bandgap energy of ZnO was found 3.2 eV. The assembled solar cell has energy conversion efficiency about of 0.03 % with fill factor of 0.25 and maximum power output of 12.8 μWatt

Production of Cellulose Acetate from Oil Palm Empty Fruit Bunches Cellulose

Cellulose acetate was produced from acetylation process oil palm empty fruit bunches cellulose which underutilized. To obtained cellulose acetate qualified was needed cellulose with high purity level which was produced through several stages are pre-hydrolysis, delignification, pulping and bleaching. The purpose of this research was to making cellulose acetate and determining the exact acetylation time from oil palm empty fruit bunches cellulose. The research was conducted several stages are cellulose extraction, cellulose acetate production with acetylation process and characterization of acetate cellulose. The production process of cellulose acetate was done with acetylation time are 15, 30, 45 and 60 minutes. The results were obtained cellulose acetate by water content range from 4.332 to 4,468%, the highest yield for 45 minutes was 189.699% and the best acetyl content for 30 minutes was 40.108%. FTIR analysis was showing carbonyl group at 1759 cm-1 and C-O group at 1234 cm-1 region. Morphology of cellulose acetate obtained was shaped cylindrical fibers and had perforated layer. Keywords: Oil Palm Empty Fruit Bunches, Cellulose Acetate, Acetylatio

Synthesis of Nanofiber from Oil Palm Empty Fruit Bunches Cellulose Acetate for Bioplastics Production

The purposes of this research were to obtain nanometer-sized fiber with electrospinning method and to produce bioplastics with addition of diethylen glicol (DEG) plasticizer. This research was conducted through several stages, namely extraction of cellulose, synthesis of cellulose acetate, sythesis of nanofibers and production of bioplastics. In the production of nanofibers cellulose acetate, electrospinning method were used with concentrations of cellulose acetate  (5, 10, and 15 %) and spinneret-collector distances (6, 8, and 10 cm) treatments.  In the production of bioplastics, solution casting method was  ​​used with micro and nano fiber-sized cellulose acetate  and addition of DEG plasticizer (0, 10, 20, and 30 %) treatments. The results of this research showed that  the lowest nanofiber diameter of 134 nm was obtained on the cellulose acetate concentration of 10% and spinneret-collector distance of 8 cm. The best mechanical characteristic was obtained on bioplastic of nanofiber celulose acetate and the addition of plasticizer at the concentration of 10%. Its mechanical characteristics were tensile strength of 3.953 MPa and elongation of 18.56%. Keywords: nano fiber, cellulose acetate, oil palm empty fruit bunches cellulose, electrospinning, bioplastics

Determining Image Opacity in Broiler Respiratory Radiographic Using ImageJ and Ansel Adam’s Zone System

The diagnosis of diseases of the respiratory, lung, and air sacs generally uses radiographic images by radiologists. Therefore, the results are very subjective, causing differences in the interpretation and diagnosis among different radiologists. A radiographic image reading needs to be made in the form of a simple, fast, and accurate algorithm. The study aimed to reduce subjectivity and be easily carried out by radiology medical personnel, especially veterinarians. This study carried out density measurements by image processing using ImageJ software on 14 radiographic images of broiler chickens. Furthermore, the density value is associated with the Ansel Adam's - grayscale system to determine the opacity of respiratory tract tissues/organs, which were previously inhaled by one of them with chitosan-iopamidol nanoparticles using a nebulizer. The results of density measurements for the category of opacity in radiographic images are that seven spot areas lead brighter (radiopaque) only in chickens that are inhaled mist maker of chitosan-iopamidol nanoparticles. Then the determination of the value range is obtained average value on two ventrodorsal radiographic images, which are inhaled by mist maker of chitosan-iopamidol nanoparticles and chitosan nanoparticle compressor. The conclusion of this study was only in chickens that were infested with mist maker chitosan-iopamidol, whose radiographic image had a radiopaque spot and middle-value area.

THE EFFECT OF HYDROTHERMAL TEMPERATURE AND UREA DOPING TIME ON THE OPTICAL PROPERTIES OF LEMONGRASS-BASED CARBON NANOPARTICLES (CNPs)

Carbon Nano Particles (CNPs) sourced from spiced lemongrass have been produced by the hydrothermal method at hydrothermal temperatures of 120, 140, 160 and 180 0C. The Stokes energy shift occurs due to this absorption transition and the spectrum width is determined by the electronic transition from one energy state to another. This event occurs due to the difference in energy between the two adjacent states due to the smaller vibrational state when compared to the electronic state of the CNPs.  The carbon nanoparticles (CNPs) size measurement results showed a peak value of 38.63 nm.  Functional group analysis by FTIR spectroscopy showed that the CNP consists of C=C, C-O, OH and C-N-C bonds. The Urbach energy (Eu) increased with increasing hydrothermal synthesis temperature at two hours (0.13, 0.16, 0.19 and 0.29) eV and three hours (0.12, 0.17, 0.19 and 0.28) eV. The bandgap energy (Eg) decreased with increasing hydrothermal synthesis temperature to two hours (2.30, 2.24, 2.00 and 1.92) eV and three hours (2.22, 2.20, 2.17 and 1.75) eV. The expansion of urea as a nitrogen source was carried out at a aqueous temperature of 180 0C for 2 hours and 3 hours within the blend of CNPs. The addition of urea gave a different effect on the bandgap energy (Eg) and Urbach energy (Eu) on the two CNPs. The bandgap energy (Eg) both increased from two hours (1.92 eV) to three hours (2 .22 eV), while urbach energy (Eu) decreased for a duration of two hours (3.336 eV) to three hours (3.330 eV) after adding urea. hydrothermal temperature due to synthesis time so that the structure of the CNPs becomes more stable and homogeneou

PENGGUNAAN EKSTRAK ANTOSIANIN KOL MERAH SEBAGAI FOTOSENSITIZER PADA SEL SURYA TiO2 NANOKRISTAL TERSENSITISASI DYE

The use of Red Cabbage’s anthocyanine extract as a photosensitizer on a Dye-Sensitized Nanocrystalline TiO2Solar Cell. A solid-state dye-sensitized nanocrystalline TiO2 solar cell utilizing anthocyanin extract form red cabbageas photosensitizer was fabricated. The solar cell was formed in sandwich structure, which two electrodes sandwichingpolymer electrolyte containing a redox couple (I-/I3-). One of the electrodes, namely working electrode, TiO2 layer onTCO (transparent conducting oxide) coated glass substrate was sensitized with anthocyanin dye as electron donor in thesystem. Another electrode was a carbon sheet as a counter electrode. Gel electrolyte based on PEG (polyethyleneglycol) containing a redox couple (I-/I3-) used instead of liquid electrolyte in this photoelectrochemical cell. Twofabricated cells have an active area of 1 cm2 were soaked with anthocyanine dye for 1 hr and 24 hrs, respectively. Thecells were tested by irradiation with halogen lamp of 24 Watt with intensity 4 mW/cm2 at a distance 30 cm. The testingresults of the cells show an ideal I-V characteristic with output parameters: open circuit voltage (VOC) of 500 mV, shortcircuit current (ISC) of 5,6 μA and 7,2 μA for each cells, fill factor (FF) of 48% for both cells, energy conversion (η) of0.023 % and 0,055 % for the cells with 1 hr and 24 hrs dye soaked, respectively.Keywords: Dye-sensitized solar cell, TiO2 electrode, Natural dye, Anthocyanine, Polymer electrolyt