Spektra: Jurnal Fisika dan Aplikasinya
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INVESTIGATION OF SUBSURFACE GROUNDWATER USING THE VES METHOD AROUND DENDAM LAKE, BENGKULU CITY, INDONESIA
Full text linkConcerns have been raised over the availability of water in the Dendam Lake neighborhood of Bengkulu City and the areas surrounding it. The location is characterized by a number of unsuccessful water wells. These issues are the direct and indirect results of the geological formations that are present in the region, specifically Aluvium (which consists of boulders, clasts, sand, silt, mud, and clay). A MAE X-612 EM resistivity meter was utilized in order to get a total of twenty Vertical Electric Sounding (VES) measurement points. Using the software programs Progress and Surfer, the data that was gathered was plotted on a two-log graph. The geoelectric layer and layer parameter maps that were made were prepared with the use of quantitative and qualitative interpretations. It was determined that there were between three and five geoelectric layers. It has been demonstrated that the resistivity of the subsurface shallow groundwater zone ranges from 10 to 20 Ωm at a depth of 4 to 15 meters. According to the findings of this research project, employing the VES geo-electrical exploration approach is likely capable of effectively outlining the subsurface and shallow groundwater. In addition, there is no information available regarding the precise depth of the groundwater table in the region. On the other hand, the underground groundwater at this location has a depth that is shallower than the norm
THE CORRELATION BETWEEN ELECTRIC CURRENT PRODUCED AND THE LIGHT SOURCE DISTANCE IN PHOTOELECTRIC EFFECT EXPERIMENTS
Full text linkIn experimental observations of the relationship between the electric current generated and the distance of the light source on the Planck constant device, it can show a comparison between the electric current generated and the variable distance of the light source. The experimental equipment specifications use the Planck constant experimental set with a 12v/35w tungsten halogen lamp, output 15v, accuracy +-0.2%, power requirement 220V, fuse rating 0.5A and red filter. Experiments using the concept of the photoelectric effect phenomenon begin by irradiating metal materials with constant photon light and then the light passes through a red light filter with a wavelength of 635 nm. The use of a filter is done by placing a 635 nm light filter on the light propagation path to the metal material, so that the light that passes through the filter is only light with a wavelength of 635 nm. The choice of the red filter is due to the fact that the frequency of light with a wavelength of 635 nm can cause electrons to come out of the metal as a result of photons hitting electrons in the metal. After the metal material is irradiated with photon light, the electron charges on the metal will be disturbed and come out of the metal. The movement of these electrons produces an electric current whose value can be seen. By testing distances of 18, 20, 22, 24, 26, 28, and 30 cm, the results of a current value of 0.528 are obtained; 0.382; 0.295; 0.232; 0.182 and 0.154. From these experiments it was shown that the further away the light source, the smaller the electric current generated due to the light. This is because the closer the distance to the light source, the more light intensity hitting the metal, this results in a greater number of photons hitting the metal
SYNTHESIZE OF TiO2 NANOPARTICLES BY PLANETARY BALL MILL FOR DYE-SENSITIZED SOLAR CELLS (DSSC) PHOTOELECTRODE APPLICATION
Full text linkIn this study, the production of TiO2 nanoparticles from microcrystalline powder was accomplished using the high-energy ball milling (HEBM) technique. Three samples were milled for 0.5, 1, and 1.5 hours. The unmilled powder was also characterized as a comparison. The X-ray diffraction (XRD) technique was utilized to investigate the changes in the microstructure of the milled powders over time. The XRD curve of milled samples showed the broadening of the diffraction peaks, which indicates a decrease in particle size after the milling process. Using the Debye–Scherrer relation, obtain the particle size that decreased from 138.43 nm before milled to 76.65 nm after 0.5 hours milled, 90.63 nm after 1 hour milled, and 83.05 nm after 1.5 hours milled. XRD analysis also showed that TiO2 was in an anatase phase before and after milling. Furthermore, two samples of TiO2, unmilled and after 0.5 hours milled, were used as a working photoelectrode of DSSC with dye from mustard leaves. DSSC efficiency was measured with a 1000-watt halogen lamp. The efficiency of DSSC with photoelectrodes using TiO2 after 0.5 hours milled, which is 0.1715, was higher than using TiO2 before milled, which is 0,0987. The Large surface area in TiO2 enhances the efficiency of DSSC, indicating that the HEBM technique is quite suitable for producing these nanoparticles for this aim
EXPERIMENTAL AND COMPUTATIONAL STUDY OF NITROGEN-DOPED TiO2 AS A PHOTOELECTRODE
Full text linkTiO2 has been widely used as a dye-sensitized solar cell (DSSC) photoelectrode, and attempts have been made to improve the performance of the photoelectrode by adding doping. This study aims to synthesize nitrogen (N) doped TiO2 as a photoelectrode. The research was carried out experimentally and computationally using X-Ray Diffraction (XRD) test equipment, Fourier Transform Infra-Red (FTIR), and quantum espresso software using the Density Functional Theory (DFT) method. XRD results showed that TiO2 has an anatase phase, and variations in the addition of nitrogen (doped N) of 10% w/w, 20% w/w, and 30% w/w did not produce a phase change. The FTIR results of N-doped TiO2 and TiO2 provide information on the functional groups of the samples. The wave number absorption area 1626 cm-1 indicates the presence of N-H bonds with a bending vibration mode. In addition, it can be seen that there is an N-H bond with a stretching vibration mode at wave number 3436 cm-1. Computational calculations searched the band gap energy of each variation of N doping, and each obtained was 3.2 eV; 2.54 eV; 2.35 eV; and 1.64 eV. The results of this study indicate that the N-doped TiO2 photoelectrode is expected to produce better DSSC efficiency because the addition of N-doped to TiO2 causes a decrease in the bandgap energy. The N doping effect causes a new energy level. The new energy level must be positioned close to the existing valence and conduction bands. As a result, the energy required for electrons to transition from the valence band to the conduction band is reduced, effectively reducing the energy gap between the two. This change in electronic structure facilitates more effortless movement of electrons, driving increased conductivity
RICE SAMPLE VAPORIATION METHOD ON METER TESTING RESISTIVE WATER CONTENT BASED ON ULTRASONIC MIST
Full text linkPercentage moisture content is an important factor in assessing the quality and quantity of agricultural commodities, such as rice. The measurement of moisture content is very important to evaluate the moisture content of rice, which directly affects its quality. However, the measurement of moisture content takes a long time, so it is necessary to have an evaporation method to shorten the time so that the moisture content of the sample is as required. In this study, the method chosen was the evaporation method with ultrasonic mist. The results showed that this ultrasonic fog controller evaporation system successfully increased the moisture content of rice samples according to the criteria needed to be used in resistive-type moisture meter testing. The ultrasonic mist controller evaporation system can increase the water content of rice samples according to the criteria needed for use in resistive-type moisture meter testing, with an average increase of 0.9% within 15 minutes, 3.4% within 30 minutes, and 4.1% within 1 hour
IMPLEMENTATION OF GABELLA METHOD AND RANDOM FOREST FOR GROUND CLUTTER DETECTION IN PADANG WEATHER RADAR DATA
Full text linkWeather radar is an active remote sensing instrument for various hydrological and meteorological applications. One advantage of weather radar is its ability to detect rainfall in space and time with high spatial resolution. However, one of the issues that contaminate radar observations is ground clutter. Ground clutter is a signal or echo from non-meteorological objects on the earth’s surface that are stationary in the time domain. Detecting and mitigating clutter effects is crucial to achieve precise weather measurements. This research aims to implement the Gabella and random forest methods to detect ground clutter in Padang weather radar data and determine the optimal method between the two. The implementation of the Gabella method for detecting ground clutter in Padang weather radar data was suboptimal. This was due to the most duplicated data at the same point being only 15.97% of the total data. Meanwhile the random forest method obtained a kappa value of 92.03%. This indicates that the random forest model created using 2000 trees as the parameter performs well. Based on these results, the random forest method identified as the most optimal approach for detecting ground clutter in Padang weather radar data
AIRCRAFT TRAFFIC NOISE ANALYSIS AT KUALANAMU INTERNATIONAL AIRPORT MEDAN
Full text linkThis study was conducted to analyze and evaluate the noise generated by aircraft traffic at Kualanamu airport. Data collection was carried out by conducting a survey directly in the field by asking airport officials about the flight frequency at Kualanamu airport and measuring ground handling noise with a sound level meter. Furthermore, the data obtained were analyzed using Excel software. From the results of data processing, it is known what variables most affect ground handling noise at Kualanamu airport. Noise measurements were taken by PT. Angkasa Pura II (Persero) in an open area at Kualanamu airport, the noise that occurs is below the specified quality standard value, which is <80 dB based on the Minister of Transportation Decree No. 17 of 2005 (Sultan Syarif Kasim International Airport, while for Kualanamu International Airport there has not been a Ministry of Transportation Decree. Because both airports are international class and are located in the coastal area of Sumatra Island, it can be assumed that they have the same noise quality standards). Furthermore, noise measurements were taken by PT. Angkasa Pura II (Persero) in the domestic and international waiting room area that the noise that occurs is above the specified quality standard value, namely (45-55) dB Zone B, according to the regulation of the minister of health 718 of 1987
HIGH STRENGTH MANGO LEAF WASTE/POLYURETHANE COMPOSITE REINFORCEMENT USING QUARTZ MATERIAL
Full text linkQuartz stone contains silica components (SiO2) which have the ability as a reinforcement material for composite materials. Quartz SEM-EDX testing shows that the quartz silica comonent is 69%. Other components contained in quartz are 34% MgO and 2% CaO. Therefore, quartz stone is used as a reinforcing material in mango leaf waste composite materials. Meanwhile, compressive strength testing of composite materials was carried out with variations of Polyurethane (PU) polymers, namely 1, 2, 3, 4, 5, 6, and 7 grams, obtaining the highest maximum pressure at 6 grams polymer mass, which is 38.91 grams. Testing of composite materials that have been given a mixture of quartz stone with a mass of Polyurethane (PU) 6 grams and a quartz stone variation of 0.03; 0,06; 0,09; 0,12; 0,15; and 0.18 grams obtained the maximum power most optimally there is a quartz mass of 0.06 grams of 40.47 grams. The strength of mango leaf composite meets the strength standard for building materials, namely concrete with a value of 20-150 MPa. This shows that quartz stone can be a composite reinforcement comprehenent for mango leaf waste
IDENTIFICATION OF PHYSICAL OCEANOGRAPHIC PARAMETERS AND MIXING TYPES AT THE TRANSITIONAL SEASON I IN THE ESTUARY OF AIR MANNA REGENCY SOUTH BENGKULU
Full text linkThe recent increase in community activity in the Air Manna Estuary of the South Bengkulu regency, will affect the physical condition of the estuary. Therefore, this research were to determine of the physical oceanographic parameters such as temperature, salinity, current velocity, tidal and the mixing type in the Air Manna estuary, South Bengkulu Regency at the transitional season I. The method used is the measurement of field data directly during high tide and low tide conditions as well as descriptive and quantitative data analysis. The results showed that the characteristics of the physical oceanographic pharameters in the Air Manna Estuary were influenced by tidal condition. The highest current speed at the mouth of the estuary is 2.6 m/s at low tide and 2.2 m/s at high tide, with the highest temperature in the upstream estuary of 27.49oC towards the sea during high tide conditions. The low salinity in the middle of the estuary of 0.99 ppt increases towards the sea with a relatively smaller distribution of salinity at low tide.The mixing type in the Air Manna Estuary is the Salt wedge estuary which has a well-certified mixing pattern, with an estuary number of 0.00019