Fabrication and Characterization of GO-Fe3O4/PSF Membrane with Phase Inversion Method

Polysulfones are hydrophobic which can reduce membrane permeability. Permeability can be increased through the application of hydrophilic materials such as GO-Fe3O4 to the polysulfone membrane so that the membrane is hydrophilic. The riset purpose to determine the effect of the percentage weight of different material compositions on the hydrophilicity properties of the polysulfone membrane. Membrane fabrication is carried out using the phase inversion method where the polymer solution is molded in a place and immersed in a coagulation bath containing non-solvent. This solvent exchange causes the polymer to form a solid matrix and become a membrane. The results showed that GO particles were successfully doped with Fe3O4 material shown by XRD analysis at a peak of 35.61˚ with a magnetite phase, while FTIR analysis showed that there was an absorption band characteristic of Fe-O streching vibrations. The results of the contact angle test on the GO-Fe3O4/PSF membrane 0.75 wt per cent were around 73.17˚ which showed the smallest hydrophobic value and the membrane surface morphology had an average pore size of 333.61 nm so that the addition of GO-Fe3O4 composites could increase membrane hydrophilicity.

The Effects of Potentiostat Scan Rate Variation on Impedance Value, Topography, and Morphology of the Polyaniline Thin Film

The effects of potentiostat scan rate on the impedance, topography, and morphology of the Polyaniline (PANi) thin film has observed in this study. PANi has deposited on the Quartz Crystal Microbalance (QCM) surface with various scan rates, and changes in the impedance value have observed through an impedance analyzer test. Topography Measurement System (TMS) has observed the layer topography, while the layer morphology has observed using optical microscopy and Scanning Electron Microscope (SEM). The results have shown that the best sample has a scan rate of 10 mV/s, with a low impedance value indicating the layer has rigid. The variation in scan rate can affect the impedance value, but it is not significant and does not indicate a damping effect on QCM. A homogeneous layer is deposited at a low scan rate from topography and morphological observations, while a high scan rate results in an inhomogeneous layer.

Identification of Elemental Composition and Heavy Metal Content in Maninjau Lake Sediment Using X-Ray Fluorescence (MNJ 18-41B)

Maninjau Lake is a caldera lake located in Agam, West Sumatra. This lake was formed from the volcanic activity of Mount Maninjau Purba about 60,000 years ago. The volcanic material resulting from the eruption is scattered and deposited in various places, one of which is in lake sediments. Volcanic ash contains various types of elements, including heavy metal elements. This study aims to determine the composition and content of heavy metal in the sediments of Maninjau Lake. The sample analyzed was MNJ 18-41B with a core length of 440 mm, focusing on specimens 148 mm and 376 mm. The selection is a specimen based on the magnetic susceptibility value obtained from the measurement meter susceptibility of the MS2E. Specimen 148 has a value susceptibility low of 2.1 × 10-8 m3/kg, while the 376 specimens have the highest value of susceptibility, the highest 141 × 10-8 m3/kg. The content of sediment elements was determined using the results of X-Ray Fluorescence (XRF) measurements. The measurement results showed that the mineral-forming elements in the sediments of Lake Maninjau were dominated by Si, Fe, Rh, and Zr. In contrast, the highest heavy metal elements are Mn, Fe, Sr, and Rh. Based on the elemental composition and mineral oxide compounds in the sediments of Lake Maninjau derived from volcanic ash.

Reconstruction of Bandung Groundwater Basin Model Using Schlumberger Configuration Geoelectric Method

Bandung is a city with rapid industrial development and a dense population. It causes the need for clean water to be huge, so it impacts groundwater extraction on a large scale. The Bandung Basin, which is a good reservoir for groundwater, will be disturbed if conservation and monitoring efforts are not carried out in the presence of groundwater. This study focuses on reconstructing the groundwater model in the Bandung Basin using the Schlumberger geoelectric method. After taking and analyzing the data, it was found that the resistivity value of the location of the presence of groundwater is depicted into three groundwater basins, namely the Bandung-Soreang groundwater basin, the Lembang groundwater basin, and the Batujajar groundwater basin. Unfettered aquifers, relatively aquitard in nature, are in the upper layer of the coal sandstone, claystone and sandstone units. The confined aquifer in the sand unit is under the sandy claystone layer.

Trial of DC Submersible Pump 12 Volt 50 Watt with Solar Power and Relationship between Water Discharge and Storage Height

One of the biggest problems for farmers in the dry season is the lack of water supply for irrigation. Currently, various types of pumps have been widely used, such as fuel pumps and pumps with PLN electricity. However, the costs required to operate these tools are pretty expensive. The solution to overcome this is using DC submersible pumps using solar panels as an energy source. The purposes of this study are to (1) determine the duration of operation of the DC submersible pump with the specifications of the battery and solar panels used, and (2) determine the productivity of the DC submersible pump in terms of the resulting discharge for various storage height conditions used. The research method used is an experimental research method using a quantitative approach. The results of this study are (1) DC submersible pump can operate for 240 minutes with 20 Ah battery at maximum voltage and uses 60 Wp solar panels, and (2) the height of the storage has an effect on the resulting discharge, there is a reduction in the resulting discharge every 0.5 meters increase in the height of the storage. Based on the analysis results, the maximum height limit for submersible pump push is 3.7 meters using a 3 per 4 inch hose. The results of this study can be a reference for farmers or users to determine the height of the water storage.

Synthesis and Characterization of Magnesium Acetate Doped MAPbI3 Perovskite Solar Cells with Carbon Electrodes

The organometal perovskite trihalide (MAPbI3) based solar cell has attracted the attention of many researchers because it has the potential to be a third-generation solar cell that has high efficiency, flexibility and transparency. However, this perovskite solar cell is sensitive to the environment and less stable. In this study, a performance study of perovskite solar cells with the addition of magnesium acetate was carried out in the MAPbI3 synthesis process and the use of carbon electrodes. In general, the perovskite solar cell arrangement in this study consisted of ITO/TiO2 mp/MAPbI3/carbon paste. Mesoporous TiO2 (mp) coating was carried out using the screen printing method, while MAPbI3 coating was carried out with a two-stage spin coating with the addition of magnesium acetate after PbI2 coating in the first stage. The samples obtained were then characterized using an X-Ray Diffractometer (XRD). Analysis of the performance of solar cells was carried out by measuring I-V and photoresponses using a solar simulator. XRD results show that MAPbI3 film has been formed even though there is still impurity of PbI2. The resulting solar cell performance has a value of Voc equals 3.45 V and Jsc equals 0.04 with an efficiency of around 0.09 per cent. In the measurement of the response photo, the increase in time value was 7.29 s and the decay time was 34.38 s. The low-efficiency value is probably due to the absence of a layer of hole transfer materials (HTM) and the presence of PbI2 impurities. However, the stability of the photoresponse pattern against time has shown quite good results even though the response is increased or the decay is slow.

Performance of Dye Sensitized Solar Cells (DSSCs) with ZnO Nanorod Electrode in Different Seed Solution

Studies of comparing the performance of photoelectrode for dye-sensitized solar cells (DSSCs) continue to be carried out and developed. The ZnO nanorods as an electrode for DSSCs have been shown to have high electron collection due to the capability of electron photoexcitation and increased electron transport. Various methods of making ZnO nanorods have been studied and developed. However, the method requires controlled conditions under high temperature and pressure, thus limiting the commercialization of ZnO nanorods. Therefore, the seed solution-based hydrothermal method was chosen in the ZnO nanorod deposition process because it is an effective method, low-cost and easier fabrication process. The method of growing ZnO nanorod was carried out with three times of growing for 6 hours. ZnO nanorod was synthesized using different seed solutions, namely sample 1 and sample 2 by using methoxy and isopropanol, respectively. In this work, the SEM image shows the growth of ZnO nanorods vertically aligned on the FTO substrate and resulted in a smaller diameter for the isopropanol seed solution. The smaller diameter of the ZnO nanorod provides a larger surface area then increasing the total amount of dye attached to the ZnO nanorod and improve the photovoltaic performance.

Hydrocarbon Mapping on Reservoir Carbonate Using AVO Inversion Method

Amplitude Versus Offset (AVO) inversion has been applied for reservoir analysis focused on the horizon carbonate Peutu and Belumai. Simultaneous inversion analysis is used to determine gas anomaly inside carbonate-rocks and it’s spread laterally around target zones. It is based on the fact that small Vpand Vs value changes are going to show the better anomaly to identify reservoir fluid content. The AVO inversion method applies angle gather data as the input and then it is inverted to produce P impedance (Zp) and S impedance (Zs). Zp and Zs are derived to produce Lambda-Rho and Mu-Rho that are sensitive to fluid and lithology. Value of Mu-Rho between 44–65 Gpa gr/cc while value of Lambda-Rho smaller than 10 Gpa gr/cc (for carbonate-rock filled by fluid). This research found that Lambda-Rho is the best parameter to show the existence of hydrocarbon in the case of gas. While Mu-Rho is the best parameter to show the differences in lithology.

Reduced Graphene Oxide/Polyvinyl Alcohol Nanofibers Fabricated by Electrospinning Technique as An Ideal Candidate for Organic Solar Cell Devices

Functionalization of rGO that previously obtained by chemical reduction using hydrazine hydrate, has been done by changing its morphology into nanofiber with electrospinning technique and using PVA as a polymer matrix. The rGO nanofibers that had been formed were then characterized using Fourier Transformation-Infra Red (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), and UV-Vis Spectrophotometer. FTIR spectroscopy confirmed the presence of C – C group and C = O group in nanofibers. SEM showed the change of nanofibers morphology which is marked by the increasing of fibres diameter and the hollow fibres become brighter. Furthermore, the effect of rGO concentration to nanofiber optical properties was confirmed by UV-Vis spectrophotometer. According to this characterization, the absorbance of rGO/PVA nanofiber is decreased due to increased rGO concentration. The detail of optical properties of rGO is studied through complex refractive index and dielectric constant in which Kramers-Kronig transformation is then employed to calculate complex refractive index and complex dielectric constant. From the data, the optical properties of rGO/PVA nanofibers indicating that rGO/PVA nanofibers can be applied as transparent electrode an organic solar cell devices.

The Virtual Lock-in Amplifiers - Accuracy of Measurement Results in Light Transmission Experiments

This research focuses on the analysis of the measurement result of the virtual lock-in amplifier (virtual-LIA) in the light transmission experiment as the trial step of developing the virtual-LIA. The virtual-LIA used in this research is designed by using the Vernier sensor DAQ as the data acquisition and the LabVIEW as the programming media. The design of virtual-LIA is based on the mathematical operations of LIA. The type of virtual-LIA is a single phase with the capabilities to process the external reference signal. Light transmission experiments are carried out using formazin polymer suspension with turbidity level of 3000 NTU, 3500 NTU, and 4000 NTU as the medium in which light is passed. The accuracy of the measurement results is known by comparing the results of virtual-LIA with real-LIA SR510. The experiments are also carried out in bright and darkroom conditions to determine the ability of virtual-LIA in reducing noise signals. Based on the experiment, the results obtained that the measurement accuracy of the virtual-LIA developed is above 94% compared to the LIA SR510. Virtual-LIA could measure small signals with and without noise with the average percentage of differences measured between dark and bright conditions is 0.54%.