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The incorporation of nanoparticles into carrageenan matrix film has recently been carried out to improve the film properties. Therefore, the dispersion of nanoparticles in the suspension is an important thing to be evaluated to enhance their performance in the matrix film. This study aims to produce suspension of SiO2 and ZnO nanoparticles dispersing by bead milling process. The effect of bead milling process in the suspension of SiO2, ZnO, and their combination (1:1, 1:2, 1:3) were evaluated using particle size distribution and dispersion stability analysis. The result showed that bead milling process can reduce the particle size of the nanoparticle suspensions. The nanoparticles in the suspensions before bead milling have particle size in the range of 700-2000 nm in mean size, whereas after bead milling, the particle size reduce to about 160-900 nm, except ZnO suspension. After bead milling process, the suspension of SiO2-ZnO nanoparticles combination had a smaller particle size than the suspension of SiO2 and ZnO separately. Generally, the dispersion stability has decreased after bead milling in all nanoparticle suspension. [ABSTRACT FROM AUTHOR]

Manganese doped Calcium Aluminate (CaAl2O4:Mn2+) particle was synthesized by a simple solution method. To investigate crystal structure, purity level, morphology and luminescence of CaAl2O4, the concentration of Mn2+ ions was varied 0; 0.1; 0.5; 1 and 5 at% of Ca2+ . Crystal structure, purity level, particle size, morphology and luminescence of CaAl2O4 have been measured by characterization of XRD, XRF, PSA, SEM and PL. The x-ray diffraction pattern in conformity with JCPDS no. 70-0314 with crystal structure monoclinic phase. The crystallite size of CaAl2O4 was increasing by increasing the concentration of Mn2+ but decrease at concentration of Mn2+ 0.1 at%. The crystal lattice parameter a was increase while the crystal lattice parameters b and c decrease as the Mn2+ concentration increase. The purity level of CaAl2O4 confirms that Mn2+ ions have been successfully replaced Ca2+ ions in the CaAl2O4 lattice. The SEM results show that CaAl2O4:Mn2+ had a randomized structure in micro size. The PSA results showed that CaAl2O4 had smaller particle sizes around 518 nm at a concentration of Mn2+ 1 at%. The photoluminescence spectrum shows emission at 342 nm and highest intensity at concentration of Mn2+ 0.5 at%. This correlated with photoluminescence excitation shows an excitation peak at 280 nm. [ABSTRACT FROM AUTHOR]

Microheater is the main component in gas sensor characterized by their sensitivity, selectivity, and time response of gas sensor which is depend on the microheater temperature stability. A Cu microheater was developed and utilized AT-Mega 8535 controller using a PWM (pulse width modulation) method. This control system is interfaced to the PC to observe the real time temperature response of the microheater. Three initial resistance (R0) variations of microheater were developed in an open loop control system. The power characteristic of designed microheater depends on the specified microheater initial resistance. The smaller R0, the less power required to reach a temperature setting value. The developed microheater was designed to reach a temperature setting value of 250oC having resistance 0.531 Ω for 1.979 Watt and 0.265 Ω for 1.072 Watt respectively. The results of the investigation on the control performances shows microheater-control system achieved operating temperature up to 250oC. The response of the temperature control shows smallest R0 resulted in a high stability with short settling time, short delay time and small ripple for temperature setting values higher than 150oC. The obtained error of microheater temperature with R0 = 0.265 is 8.596%. It is concluded that the developed microheater can be utilized as a component of a gas sensor. [ABSTRACT FROM AUTHOR]

Microheater is the main component in gas sensor characterized by their sensitivity, selectivity, and time response of gas sensor which is depend on the microheater temperature stability. A Cu microheater was developed and utilized AT-Mega 8535 controller using a PWM (pulse width modulation) method. This control system is interfaced to the PC to observe the real time temperature response of the microheater. Three initial resistance (R0) variations of microheater were developed in an open loop control system. The power characteristic of designed microheater depends on the specified microheater initial resistance. The smaller R0, the less power required to reach a temperature setting value. The developed microheater was designed to reach a temperature setting value of 250°C having resistance 0.531 Ω for 1.979 Watt and 0.265 Ω for 1.072 Watt respectively. The results of the investigation on the control performances shows microheater-control system achieved operating temperature up to 250oC. The response of the temperature control shows smallest R0 resulted in a high stability with short settling time, short delay time and small ripple for temperature setting values higher than 150oC. The obtained error of microheater temperature with R0 = 0.265 is 8.596%. It is concluded that the developed microheater can be utilized as a component of a gas sensor. [ABSTRACT FROM AUTHOR]

Graphite oxide is widely use in renewable energy application such as solar cells, fuel-cells, battery electrodes, catalyst support, etc. This paper reports the preparation of graphite oxide from Indonesian natural graphite by sodium cholate intercalation. The enrichment process of as received graphite with carbon content of 60% was carried out by using acid leaching (HF) method. The enrichment process successfully obtained graphite with carbon content 95.61% with contaminant minerals observed by EDS were magnesium and aluminum. Purified graphite was then intercalated by sodium cholate at various concentration and sonication time. The XRD results shows that preparation with concentration of sodium cholate 2 Wt.% and sonication 10 hours formed a peak characteristic of graphite oxide at 2θ=15°. In addition, the successful oxidation process designated by the C/O ratio of 15.75 observed from EDS and supported by the present of functional C-H and C-O obtained from the FTIR observation. It is concluded that the graphite oxide successfully prepared by intercalation using sodium cholate and sonication. [ABSTRACT FROM AUTHOR]

Atomization is an important part in Spray Pyrolysis (SP) process which is applied to synthesize submicron or nano sized particles or to deposit thin film. Ultrasonic Nebulizer (UN) is usually use in SP due to its homogeneous droplets production with size between 1-5 μm. The drawback of the UN is low droplets production rate. In this research, we successfully developed a Digital Ultrasonic Nebulizer (DUN) with high droplets production rate using two ultrasonic traducers with applied frequency of 2.4 MHz. The result of DUN atomization was improved 4-6 fold compare to the conventional UN. The DUN also has an additional digital features such as pushbutton, LCD and microcontroller which is allow to set duration and applied voltage. [ABSTRACT FROM AUTHOR]

Synthesis of nanoparticles and processing of nanocomposites are the essential steps in the application of nanotechnology in various industrial fields including environmental remediation and renewable energy conversion. It is very important to develop their synthesis methods in which nanoparticles having controlled characteristics including size distribution, morphologies, and compositions. Thus, the process needs to be simple, low in cost, and have both continuous operation and high production rate to meet the industrial requirements. The synthesis method for nanoparticles and the development of nanoparticles dispersion technology will be reviewed; nanoparticles synthesis by pulse combustion spray pyrolysis to improve production rate and dispersion of nanoparticles by bead mill method. Furthermore, the availability of the raw materials are also very important to produce the end products economically. The current development on the graphite processing and the future development on the end product in Indonesia will be reviewed. [ABSTRACT FROM AUTHOR]

Solution phase method was used to synthesis nanocrystal LaPO4:Eu3+. Polyethylene glycol with vary molecular weight (MW) was added to allow an exothermic reaction to get a high crystalinity of LaPO4:Eu3+. The x-ray pattern of as prepared LaPO4 was obtained by using an X'pert PANalytical diffractometer with CuKα radiation (λ = 1.5406 Å) and the photoluminescent measurement spectra is obtained by using Fluorescence Spectrometer LS55, Perkin Elmer. The additional of various MW of polyethylene glycol into the precursor solution of LaPO4:Eu3+ affected the crystal structure and luminescent properties. Higher MW of PEG depressing the luminescent spectra. The emission origin from 5D0-7F4 transition vanished by additional 500,000 and 2,000,000 MW of PEG. [ABSTRACT FROM AUTHOR]

The silica (SiO2) particle was synthesized using the precipitation method of sodium silicate (Na2SiO3) precursor by additional HCl as precipitant. In this paper, the precipitant was mixed directly to the solution of sodium silicate (Na2SiO3) in contrast to the conventional dropwise technique which prevented a high production rate. The dropwise of HCl was carried out to know the effect of pH at two different temperature 25 °C (T20) and 80 °C (T80) on the obtained particles. It was obtained that the optimized process was at temperature 25 C. Subsequently, the mixing technique of HCl (conventional dropwise and direct mixing) were investigated at temperature 25 °C. The result showed that direct mixing technique resulted in high production rate with acceptable size and dispersion of silica nanoparticles. It is also highlighted that the proposed direct mixing technique of HCl received a simple and faster-precipitated process in large scale production. Therefore, it is proposed that for the scale-up production of silica nanoparticle by precipitation of the sodium silicate (Na2SiO3) precursor with additional of HCl may be prepared by direct mixing method at pH 7 in temperature 25°C. [ABSTRACT FROM AUTHOR]

Graphene quantum dots (GQDs) represent single layers up to dozens of graphene layers smaller than 30 nm. GQDs are newish molecules that have aroused great interest in research because of their exceptional and manageable optical, electrical, chemical, and structural properties. In this work, we report electrostatic potential energy maps, or molecular electrostatic potential surfaces, illustrate the charge distributions of GQDs three-dimensionally. Knowledge of the charge distributions can be used to determine how GQDs interact with one another. To analyze the distribution of molecular charges accurately, a large number of electrostatic potential energy values must be calculated. The best way to transmit these data is to visualize them as in the electrostatic potential map. A ZINDO semi-empirical quantum chemistry method then imposes the calculated data onto an electron density model of the GQDs derived from the Schrödinger equation. To make the electrostatic potential energy data of GQDs easy to interpret, a color spectrum, with red as the lowest electrostatic potential energy value and blue as the highest, is employed to convey the varying intensities of the electrostatic potential energy values. The results of the four GQD system quantum models suggest that the energy of the ionization potential lies in a range of -7.20 eV to -5.31 eV and the electron affinity is -2.65 to -0.24 eV. [ABSTRACT FROM AUTHOR]

Smart grid and distributed generation should be the solution of the global climate change and the crisis energy of the main source of electrical power generation which is fossil fuel. In order to meet the rising electrical power demand and increasing service quality demands, as well as reduce pollution, the existing power grid infrastructure should be developed into a smart grid and distributed power generation which provide a great opportunity to address issues related to energy efficiency, energy security, power quality and aging infrastructure systems. The conventional of the existing distributed generation system is an AC grid while for a renewable resources requires a DC grid system. This paper explores the model of smart DC grid by introducing a model of smart DC grid with the stable power generation give a minimal and compressed circuitry that can be implemented very cost-effectively with simple components. The PC based application software for controlling was developed to show the condition of the grid and to control the grid become 'smart'. The model is then subjected to a severe system perturbation, such as incremental change in loads to test the performance of the system again stability. It is concluded that the system able to detect and controlled the voltage stability which indicating the ability of power system to maintain steady voltage within permissible rangers in normal condition. [ABSTRACT FROM AUTHOR]

Smart grid and distributed generation should be the solution of the global climate change and the crisis energy of the main source of electrical power generation which is fossil fuel. In order to meet the rising electrical power demand and increasing service quality demands, as well as reduce pollution, the existing power grid infrastructure should be developed into a smart grid and distributed power generation which provide a great opportunity to address issues related to energy efficiency, energy security, power quality and aging infrastructure systems. The conventional of the existing distributed generation system is an AC grid while for a renewable resources requires a DC grid system. This paper explores the model of smart DC grid by introducing a model of smart DC grid with the stable power generation give a minimal and compressed circuitry that can be implemented very cost-effectively with simple components. The PC based application software for controlling was developed to show the condition of the grid and to control the grid become 'smart'. The model is then subjected to a severe system perturbation, such as incremental change in loads to test the performance of the system again stability. It is concluded that the system able to detect and controlled the voltage stability which indicating the ability of power system to maintain steady voltage within permissible rangers in normal condition. [ABSTRACT FROM AUTHOR]

Water is one of the most elements of life. As the population of the world has increased, our sources of clean water have decreased. Handling a clean water quality is one of the key challenges to avoid the scarcity of clean water, included for aquaculture system. This paper reports the effect of using fine bubbles for handling aquaculture wastewater treatment plant (WWTP). The integration of fine bubbles (FBs) generator on WWTP system is a promising method for generating fine bubbles and its ability to improve water quality parameters such as dissolved oxygen (DO), turbidity, TDS, and pH level. The performance of WWTP system using fine bubbles was tested for 5 days and the experimental results showed that WWTP system can increase dissolved oxygen from 4.5 mg/L to 7.9 mg/L. It can reduce turbidity levels from 35 NTU to 11 NTU and reduce the TDS level from 124.9 ppm to 101.5 ppm. Based on the experimental results, the application of fine bubbles technology potentially to improves the performance of WWTP system, including for developing an aquaculture system. [ABSTRACT FROM AUTHOR]

Fourier Transform Infrared Spectroscopy (FTIR) is very sensitive to the chemical surface of nanoparticles. FTIR spectra were measured and used to identify functional groups in the material. A simple comparison of standard spectra and samples proves that the FTIR technique is useful for monitoring functional groups in a mixed suspension. In this study, the chemical interaction between silica dioxide (SiO2) and zinc oxide (ZnO) nanoparticles with SDS surfactant and water was evaluated using FTIR spectroscopy with wave numbers of 500-4000 cm-1 . FTIR analysis was carried out on nanoparticle suspension material and SiO2-ZnO nanoparticle suspension with different ratios (1:1, 1:2 and 1:3% w/w carrageenan). The SiO2-ZnO nanoparticle suspension will be used as a filler in carrageenan bio-nanocomposite films through beads milling process. The results showed that in all suspension formulations identified a new functional group (Si−OH) as an interaction between Si elements and OH (hydroxyl groups) from water. Typical functional groups in each material are identified in nanoparticle suspension in shifting wave numbers. [ABSTRACT FROM AUTHOR]

Reduced graphene oxide (rGO) is considered as one of chemically derived graphene. Synthesis of graphene oxide (GO) is a prior step for making rGO. Graphene oxide can be described as a random distribution of oxidized areas with some oxygen-containing functional group in a carbon atom plane. In the present study GO powder was prepared by the Hummers method. The obtained material from Hummer's method was identified as GO powder by XRD and FTIR characterization. After the Hummers method, the resulted GO powder mixed with nickel sulfate as the catalyst, treated in Ar/H2 (4:1) environment under microwave irradiation. The Ar and H2 gases were expected to release the oxygen from the GO powder and to prevent the released oxygen back to the material. In this study, we did variations on the flowrate of Ar/H2 gases, the mass of GO powder in the system and the microwave power. The optimum oxygen group reduction has occurred when the material was treated in the Ar/H2 gas flow rate of 0.4 liters/minute, the sample mass of 0.5 g and the microwave power of 720 Watt as the reduction of oxygen atomic bond confirmed by FTIR spectrum. [ABSTRACT FROM AUTHOR]

This study has been investigated the mass ratio effect of chitosan and sodium tripolyphosphate in the ionic gelation method to produce fine chitosan suspension. In addition, the introduced of Lab-scale beads milling using 0.08 to 0.12 mm yttrium stabilized zirconia and applied the food-grade surfactant to obtain well-dispersed particles. The suspension was characterized by particle size analyzer, FT-IR spectroscopy, and SEM. The results show that the increase in mass ratio Cs/TPP could be gradually decreasing of size based on mean size distribution. After beads milling proses and addition of tween 80 as the surfactant, the morphology of Cs/TPP can breakdown of large particles into downsizing agglomerated particles with the solid surface. It was found that the beads milling process can be applied to prepare fine Cs/TPP suspension by proper adjustment of surfactant. [ABSTRACT FROM AUTHOR]

In this paper, degradation of methylene blue in aqueous solution by combination of micro/nano bubbles (MNBs) with conventional oxidation treatment i.e. Ozone and Hydrogen Peroxide (H2O2) was examined. The treatment was performed by four experimental model using macro ozone as the control treatment. The treatment system including fine bubbles produced by (FBs) generator with power consumption of 125 watt, ozone generator (production of 400 mg/h), and hydrogen peroxide (H2O2 30%) solution with concentration 10 ppm. The samples were analyzed every 15 minutes during 2 h with turbidity meter. The results show that the potential degradation of Methylene Blue with higher residual turbidity obtained from H2O2 assisted air fine bubbles + macro ozone treatment in short time after 60 minutes of treatment. The result indicated the degradation of methylene blue finely divided into organic and inorganic matter and to be absorbed of light. On the other hand, macro ozone can degradation of methylene after 180 minutes of treatment and produce less residual turbidity. [ABSTRACT FROM AUTHOR]

Silica scaling is formed by separation process in the geothermal brine transport. Its existence is considered unfavorable because it disturbs efficiency of the geothermal industry. On the other hand, the application of colloidal silica nanoparticles is widely used. As the consequences the natural silica obtained from scaling process are possible to be examined and utilized. One of the practical forms for various application is colloidal silica. In this study the colloidal silica was developed from natural silica formed by geothermal scaling of Dieng power plant, West Java, Indonesia. In colloidal form the colloid stability is very important. It can be improved by the addition of surfactants and by beads milling process to reduce the particle size. The main objective of this study was to determine the most effective type of surfactant to stabilize colloidal silica. By reviewing the zeta potential value of colloids, adding cationic, anionic, and nonionic surfactants, and determined the effect of the milling time on the size distribution of the colloid particles. Determination of overall stability is done by zeta potential and particle size analyzer (PSA). The results showed that the optimum stability was obtained by the addition of 0.1% PEG 6000 nonionic surfactant with a zeta potential -32.7 mV. Through the beads mill method, 134 nm diameter of silica particles suspended in water was observed, obtained through milling for 3 hours and the optimum stability was obtained through milling for 5 hours, with zeta potential -41 mV. [ABSTRACT FROM AUTHOR]

Iron sand is one of the abundant natural resources in Indonesia, especially on the south coast of Cidaun; West Java which is the basic material for building and metal industry. Iron mineral content is generally metal oxide such as magnetite, hematite and silica/quartz. Sand with iron content used in this study is derived from beach sand Desa Kertajadi, Kecamatan Cidaun, Kabupaten Cianjur, Jawa Barat. Then mass of 2 kg sand was separated using a magnetic separator in order to obtain magnetic and nonmagnetic mineral content. After nine rounds of separation takes two different types of samples that are no separation sand (TS) sample and concentrate in the third separation (S3) sample. The sample is then examined by X-Ray Diffraction (XRD) measurement and analyzed quantitatively using MAUD software to determine the content of Fe3O4 (magnetite) by using the Rietveld refinement method from XRD data. As the analysis result, the magnetite content contained in iron sand is counted quantitatively for each different sample. For iron sand samples (TS) yielding a 24.27 percent of magnetite and a third concentrate separation sample (S3) yields 61.98 percent. [ABSTRACT FROM AUTHOR]

Lantana camara is a notorious weed that has various uses in folk medicine. The L. camara leaf extract produces a number of metabolites and some have been shown biological properties. A number of studies reported the biological pharmacological activities of L. camara as well as the toxicity on insect pests. The study of physicochemical characterizations of L. camara crude leaf extract may lead to the prospect of L. camara as potential biopesticides source. Crocidolomia pavonana larvae are one of cabbage insect pest that becomes resistant to chemical insecticides, so alternative botanical insecticides are expected to control more environmentally friendly. The phytochemical analysis of L. camara leaf ethanolic extract was investigated in this study. Subsequently, the physical characterizations i.e. particle size analysis, potential zeta, and FTIR analysis was done. The biological toxicity test using spray application method. The suspension that’s sprayed onto the leaf disc area was led to dry and the powder-shaped suspension residues were attached on the leaf surface, then the 3rd instar C. pavonana were exposed on it. The parameters are the mortality of larvae at 24, 48 and 72 hours, the average mortality was then analyzed statistically using probit test to determine the LC50 value. The result showed that the L. camara leaf ethanolic extract of with polydisperse particles (PI=0.726), particle size=541.7 nm − 4265.8 nm, and the particles tend to incipient instability (Z = -14mV) and pH=6. The extract had toxicant bioactivity on 3rd instar larvae C. pavonana (80 % mortality at 24h and 100% mortality at 48h and 72h) with LC50 1.88% at 24 h, 1.21% at 48h and 0.99% at 72h, considered as a medium toxic category. FTIR-spectra showed 0-H, C-H absorptions groups revealed to terpenoids, the absorptions groups of (O-H),(C-H), (C=C), (R-COOH) and C-O-C glycoside linkages to the sapogenins that confirmed the presence of saponins, the absorbance of (-OH) and aromatics ring indicated the presence of steroids and the absorbance of the (C-N) aliphatic amines indicate presence of alkaloids. These compounds present in the phytochemical result of analysis (triterpenoids, saponins, steroids, and alkaloids). Based on the result of physicochemical characterizations are recommended to allow the next study Lantana prospect for new biopesticides to control C. pavonana larvae. [ABSTRACT FROM AUTHOR]

This study aims to develop film for food packaging application with high UV-screening, transparency and water barrier properties. Semi refined iota carrageenan (SRiC) nanocomposite films prepared by addition of zinc oxide (ZnO) nanoparticles as nanofiller using solution casting method. The effect of nanofiller with different concentration (0%, 0.5%, 1.0%, 1.5% w/w carrageenan) on UV-screening, transparency and water barrier properties of films were tested. The water barrier properties of the films were studied by measuring water vapor permeability (WVP) and the optical properties of the films were studied by using UV-Vis spectrophotometer at 280 nm for UV-screening test and at 660 nm for transparency test. WVP value of carrageenan films with addition of ZnO is low compared to a control carrageenan film and the lowest WVP value was found for the film with addition of 1.5% of ZnO. These result indicate that the addition of ZnO had a positive effect on the water barrier properties of the carrageenan matrix. Increase in the concentration of nanofiller leads to an increase in the UV-screening properties. Among all the films, carrageenan film with 1.5% ZnO has the highest UV-screening. The result showed that adding 0.5% and 1.0% of ZnO was insignificantly affect transparency of the films, however the transparency decreased sligthly when 1.5% ZnO was added. In conclusion, incorporating no more than 1.0% of ZnO to the films can obtain films with high UV-screening, transparency and water barrier properties and suitable for food packaging application. [ABSTRACT FROM AUTHOR]

Helicoverpa armigera (Hubner) is one of a serious pest of horticulture in Indonesia. Helicoverpa armigera Nuclear Polyhedrovirus (HaNPV) has attracted interest for many researchers as a pest control for larvae of this species. Currently, we investigating the agrochemical formulations of HaNPV by introducing nanotechnology. Thus it is required an acceptable efficiency of insect stock cultures equipped with advance instruments to resolve the difficulties on insect stock seasons dependency. In addition, it is important to improve the insect survival with the aid of artificial natural environment and gain high insect production. This paper reports the rearing cabinet used as preparation of stock culture includes air-conditioning system, lighting, i.e. day and night control, and the main principles on recent technical and procedural advances apparatus of the system. The rearing system was moveable, designed and build by allowing airconditioned cabinet for rearing insects, air motion and distribution as well as temperature and humidity being precisely controlled. The air was heated, humidified, and dehumidified respectively using a heater and ultrasonic nebulizer as actuators. Temperature and humidity can be controlled at any desired levels from room temperature (20°C ) to 40 ± 1°C and from 0 to 80% RH with an accuracy of ± 3% R.H. It is concluded that the recent design has acceptable performance based on the defined requirement for insect rearing and storage. [ABSTRACT FROM AUTHOR]

This paper mainly discussed the electrical performance of gas diffusion electrode of Mg-Air Cell. The gas diffusion electrodes (GDE) use a natural graphite powder as catalyst material. The effect of additional binders to the GDE have been investigated to improve electrode performances. Several types of GDE have been developed using binder materials such as epoxy resin, natural clay, carboxymethyl cellulose (CMC) and urea-formaldehyde (UF). By using discharge performance measurement, the characteristics of the as-prepared GDEs are reported. [ABSTRACT FROM AUTHOR]

This paper mainly discussed the electrical performance of gas diffusion electrode of Mg-Air Cell. The gas diffusion electrodes (GDE) use a natural graphite powder as catalyst material. The effect of additional binders to the GDE have been investigated to improve electrode performances. Several types of GDE have been developed using binder materials such as epoxy resin, natural clay, carboxymethyl cellulose (CMC) and urea-formaldehyde (UF). By using discharge performance measurement, the characteristics of the as-prepared GDEs are reported. [ABSTRACT FROM AUTHOR]

This paper report the development of a simple sedimentation potential measurement system to know the state of nanoparticles (NPs) dispersion stability The state of nanoparticles dispersion stability is very important in applications of nanoparticles since the nature of NPs is easily agglomerate. The developed sedimentation potential consist of graphite electrodes, signal conditionmg, microcontroller, and interface circuits provided with a data acquisition applications. The system was designed to obtained sedimentation potential in the range -200 to 200 mV with accuracy of 0.415 mV. From the measured sedimentation potential, the zeta potential can be determined. This system was applied to investigate stability of TiO2 NPS suspension in water media to obtain the performances of the system Those zeta potentials were determined at various condition such as vary in surface charges by controlling the pH of the suspension, vary in suspension concentrations and sedimentation time. The results show that the higher concentration of the suspension, lower zeta potential of the suspension was obtained. The zeta potential was decreased by the sedimentation time indicated that the agglomeration of particles occurred. Controlling of surface charges by controlling pH also affect the values of obtained zeta potentials. It is concluded that the developed sedimentation potential measurement successfully applied for determination of zeta potential of the TiO2 NPs suspension to evaluate the stability NPs suspension [ABSTRACT FROM AUTHOR]

Integrating Sphere (IS) is an instrument formed a cavity sphere with its inner surface act as a Lambertian reflector. IS is needed in many optical measurements which involves a high diffused reflection. In addition, IS very essential in photometry and radiometry measurement system. However, currently, IS is still an imported product which considered very expensive. The material for the sphere and inner surface coating affect the performance of the IS systems. Therefore, the main challenges in designing IS are the material engineering for the sphere and the procedure for the inner surface coating. The inner surface was coated using BaSO4 which has a low absorption and high diffuse reflection. Spectral responses of the IS system was characterized using USB2000+ and calibrated using a standard Spectralon from ocean optic. The obtained IS system used an inner surface coating from a mixed 80% Barium Sulfate (BaSO4) and 20% Nippon Elastex paint which yield a reflection factor ρ = 0.955 and amplification factor M=10.69. The validation was conducted using an emitter with known specification from Luxeon of LXHL-DW01 which produced light flux 40.5 lumen with injection current 350 mA and junction temperature Tj 25°C. [ABSTRACT FROM AUTHOR]