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One Step Synthesis of TiO2-Activated Carbon Composite Using Hydrothermal Method with Mass Variation of Activated Carbon
Full text linkOne effort to increase the photocatalytic activity of TiO2 is to immobilize it on the surface of the sorbent material. This study aims to produce TiO2-Activated Carbon (TiO2-AC) composites which have higher photocatalytic activity than TiO2, using a simple method. The synthesis of TiO2-AC composites was carried out using the hydrothermal method. The synthesis process was initiated by mixing TTIP, ethanol, H2O, and activated carbon with various masses (5 g, 10 g, 15 g, and 20 g). The mixture was then put into a hydrothermal autoclave and heated at 180°C for 12 hours. The material is then washed until the pH is neutral, and then dried. The TiO2-AC composite powder was then calcined at 500°C for 3 hours. Based on the photocatalytic test of the TiO2-AC composite on the degradation of methylene blue compounds, it was shown that composite with a mass variation of 10 g activated carbon (TiO2-AC/10) had the highest photocatalytic activity. FTIR characterization of the sample TiO2-AC/10 showed a shift in the peak wave number of the hydroxyl and carbon groups. Meanwhile, the results of morphological analysis using SEM showed that TiO2 particles had adhered to the AC surface, which was also confirmed by EDX data in the presence of Ti and O elements in the synthesized material. The results of the crystallinity analysis showed that the 100% synthesized TiO2 was the anatase phase with a crystalline size of 1.80−14.14 nm. This study open up opportunities for the development of TiO2-based composite materials for large-scale environmental remediation applications
Identifying Pore Type of Lagoon and Barrier Carbonate to Model Shear Wave Velocity in Salawati Basin by Differential Kuster-ToksÖz
No full textThe shape of pores in sedimentary rocks is dependent on the geometric structure of the rock matrix grains. Carbonate rocks have more complex pore types compared to clastic due to the effects of diagenesis and the depositional environment. The study analyzed the deposition of Kais carbonate in barrier and lagoon environments. It categorized the pores into inter-particle, moldic/vuggy, and micro-cracks. The type of pore in a rock is directly related to its stiffness and shear resistance, which influences its shear wave velocity (Vs). Thus, a higher shear modulus leads to a higher Vs value. Reservoir characterization heavily relies on the Vs data. However, this data is limited to the observed area. Therefore, Vs modeling is a more effective and efficient approach. The modeling will conduct thoroughly with the identification of the pore type. The rocks moduli are calculated by the pore inclusion method using the differential Kuster-Toksöz (DKT) equation and defining the aspect ratio, reflecting the pore type. The YP-1 well has barrier carbonate, while YP-2 and YP-3 have lagoon carbonate with inter-particle as the primary pore type. Micro-cracks on top of Kais are present. YP-4 and YP-5 have similar proportions of micro-cracks and inter-particle as dominant pore types. The predicted Vs and measured logs strongly correlate with an R2 value above 0.8. The Vs value range for micro-cracks is 2,300 ft/s to 6,000 ft/s, and for inter-particle, it is 6,000 ft/s to 8,500 ft/s. Pore types above 8,500 ft/s are very stiff (moldic pore type)
Non-Nutritive Suck Assessment Tool Development to Characterize Sucking Patterns in Infant with Various Hunger Levels
Full text linkSucking abilities are critical in early infant development, and the patterns of non-nutritive suck (NNS) have been found to potentially predict neurodevelopmental issues in the future. Proper NNS assessments are essential to ensure valid conclusions. Previous studies have shown that the level of infant arousal significantly affects NNS patterns. However, the author did not find any studies that observed the influence of infant hunger levels on NNS patterns. Therefore, this study aimed to develop an NNS assessment tool to characterize NNS patterns in infants with various hunger levels. The NNS assessment was conducted using a pressure transducer connected to a pacifier. The results showed that the level of hunger significantly affected the intra-burst frequency and the sucking pressure. The more hungry the infant, the more frequent the intra-burst frequency became, while the sucking pressure tended to decrease. The intra-burst frequency of infant sucking was 2.3, 2.46, and 2.5 Hz on average for a relative hunger index of 0.67, 0.83, and 1.0, respectively. The NNS pressure of infant sucking was 6.31, 4.51, and 2.62 kPa on average for a relative hunger index of 0.67, 0.83, and 1.0, respectively. This study's results suggest that during NNS assessments, the measurement time should consider the next feeding schedule for the infant
Characteristics of Internal Solitary Waves near Its Generation Site in the Lombok Strait, Indonesia
Full text linkEvidence of internal solitary waves (ISWs) formation through the Lee wave mechanism in the Lombok Strait was revealed from the echosounder measurements conducted in November 2017. This study is aimed to characterize the property of ISW packet formed around ~30 km away from the generation site, in the southern part of the strait above the Nusa Penida Sill (NPS), by employing Korteweg-de Vries (KdV) solution. The packet can be categorized as the early stage of ISW formation, consisting of two waves of depression, with typical amplitude of 30 m and 10 m, for the first and second wave, respectively. The waves propagated northward with a typical phase speed of ~1.2 m∙s -1. The waves drive a maximum horizontal velocity anomaly of ~0.8 m∙s - 1 and a vertical velocity anomaly of ~10 cm∙s -1. The amplitude of the ISW packet will be potentially amplified during their propagation away from the strait. This study provides an observational based understanding on the early stage of internal tides evolution in the Lombok Strait, particularly highlights the energy transfer of internal tides through the propagation of internal solitary waves
Analysis of Projected Temperature Changes in Aceh Province
Full text linkThe objective is to analyse temperature changes and their future projection in Aceh. The activities consist of collecting past and future temperature data, preparing materials for processing, and analyzing past and future temperature data (climate change projections). The data used are monthly average temperature data from data global climate model, e.g., csiromk3.6-hist-1986-2005-tas, csiromk3.6-rcp45- 2016-2035-tas, csiromk3.6-rcp45-2046-2065-tas, csiromk3.6-rcp45-2081-2100- tas, csiromk3.6-rcp85-2016-2035-tas, csiromk3.6-rcp85-2046-2065-tas, and csiromk3.6-rcp85-2081-2100-tas. The study began with reading climate data in NetCDF format using GRADS software, data processing using CDO software, providing a coordinate system using QGIS software, making climate change projection maps using ArcGIS software, and making climate change graphs using spreadsheet programs. Two scenarios, i.e., RCP4.5 and RCP8.5 are used to analyse the projected temperature changes in the short-term (2016 – 2035), medium-term (2046-2065), and long-term (2081-2100). The results show that the RCP4.5 projection shows a lower change in temperature rise than the RCP 8.5. A change in a temperature rise of up to 5°C was found in the RCP8.5 scenario
Utilization of Luminescent Carbon Nanodots from Soybean Husk Wastes for Fingerprint Identification using Tracker Software Spectrum Analysis
Full text linkVisible fingerprints (FPs) play a crucial role in forensic identification, and luminescent carbon nanodots (C-Dots) have shown promise in enhancing their visibility. However, the optimal concentration of C-Dots for effective coating remains largely unexplored. This research aimed to determine the ideal C-Dots concentration for FPs identification. The fingerprint (FP) patterns of two subjects, L and P, were analyzed, revealing intensity peaks in 200 mm - 250 mm and 100 mm - 150 mm, respectively. The FP patterns were observed using a light microscope and Tracker software spectral analysis. The C-Dots samples were produced with variation in concentrations of (%W/V) 40%, 43.4%, and 47.6%. The spectrophotometer ultraviolet-visible (UV-Vis) test of the C-Dots showed absorption peaks at 270 nm and 330 nm wavelengths. The photoluminescence test indicated that the C-Dots have cyan luminescence. The X-ray diffraction (XRD) test showed that the C-Dots were amorphous. The spectrometer Fourier transform infrared (FTIR) test showed the presence of C = C functional groups. The scanning electron microscope (SEM) images with 5000x magnification showed the surface morphology of the C-Dots mimicking crumpled papers. Using Tracker software, FPs were successfully differentiated, with the clearest visual FPs observed when using a C-Dots concentration of 43.4%. Thus, the optimal concentration of C-Dots for FP identification was 43.4%.
Sunlight Assisted Degradation of Linear Alkylbenzene Sulfonate by Floating Catalyst TiO2-Coconut Fiber
Full text linkThe increasing number of laundry businesses in Pontianak causes increased laundry waste, which is dangerous for health and the environment because anionic surfactants such as Linear Alkylbenzene Sulfonate (LAS) are hard degradable. Photocatalyst is a method that can be used to degrade the LAS structure. TiO2 carried in coconut fiber can optimize sunlight irradiation in degrading LAS content when light reaches the water's surface. This study aims to determine the characteristics and optimum activity time of photocatalyst TiO2-coconut fiber in degrading LAS. Photocatalyst characterization was carried out using XRD, XRF, and DR-UV, while the optimum activity test of photocatalysts in degrading LAS was carried out using a UV-Vis spectrophotometer. XRD diffractogram analysis showed the peaks of coconut fiber at 2θ = 22.2º, 34.8º and TiO2 at 2θ = 25.3º, 37.8º, 48.1º, 55.1º, and 62.1º. The TiO2 attached to the fiber after being synthesized was 21.12%. The band gap of TiO2 and TiO2-coconut fiber is 3.21 and 3.18 eV, with light absorption at 386.5 and 390.3 nm. Photocatalyst was carried out in LAS with a mass ratio of TiO2 and coconut fiber of 20:80; 30:70; 40:60, and 50:50 w/w with a time range of 0, 30, 60, 90, and 120 minutes. The results of photocatalysis of TiO2-coconut fiber in a ratio of 20:80 w/w showed the optimum photocatalytic activity at 120 minutes with the highest degradation rate of 80.43%. This research is expected to be applied as an alternative to handling LAS in laundry industry waste
Identification and Classification of Thiamine with Amperometric Biosensor Based on Saccharomyces cerevisiae and Principal Component Analysis
Full text linkVitamin B1 (thiamine) plays an important role in various metabolic processes and is one of the main factors in the body's health. Thiamine excess and deficiency in the body might cause a variety of diseases such as shortness of breath, beriberi, and heart failure, hence thiamine levels must be detected as a reference for intake. The present research detected thiamine using the amperometric biosensor method and the yeast Saccharomyces cerevisiae as a bioreceptor. Dissolved oxygen (DO) level measurement parameters are considered based on yeast cell metabolism. Thiamine was treated with various concentrations of 15 mM, 30 mM, 45 mM, 60 mM, and 75 mM. The measurement results are in the voltage range of 1912–1964 mV, where the addition of thiamine causes an increase in the reproducibility and growth rate of yeast cells. The ideal characteristics of the biosensor based on the parameters of sensitivity, linearity, and stability was also carried out, which resulted in successive biosensor measurements of 0.925 mV/mM, a correlation coefficient of r = 0.9868, and a decrease in the voltage response of the biosensor up to 4.97% from its initial activity. The measured data were grouped and classified using principal component analysis (PCA), which resulted in a total accumulated data variance percentage of 84.5% and an eigenvalue > 1 for both PCs. It is intended that the findings of this research can be utilized as a reference for controlling vitamin consumption levels that have an impact on health
Peningkatan Kinerja Bio-Baterai Nanas Dengan Penambahan Pasta Aki Bekas dan Natrium Benzoat
Full text linkTelah dilakukan penelitian mengenai pengaruh variasi penambahan aki dan natrium benzoat dari elektrolit kulit nanas terhadap peningkatan kinerja biobaterai. Penelitian ini bertujuan untuk mengetahui pengaruh variasi penambahan aki dan natrium benzoat dalam meningkatkan kinerja biobaterai dari kulit nanas sebagai elektrolit. Variasi campuran yang diukur yaitu elektrolit kulit nanas murni, elektrolit kulit nanas murni ditambah aki dan leektrolit kulit nanas murni ditambah aki ditambah natrium benzoat dengan pasangan elektroda yang digunakan yaitu Cu-Zn dan Al-Zn serta waktu penurunan pada elektrolit membuktikan tingkat maksimum kinerja dari biobaterai. Pengukuran karakteristik elektrik menggunakan lampu LED. Tegangan maksimum dihasilkan oleh variasi elektrolit kulit nanas murni dengan penambahan aki dan natrium benzoat dengan tegangan maksimum yaitu 8,5 V dan arus maksimum 9.50 mA serta daya maksimumnya 96,2 mW serta penurunan nilai tegangan dan arus selama 7 hari menghasilkan tegangan minimum 3,6 V dan arus minium 1,40 mA serta daya minimum sebesar 50,4 mW. Hal ini membuktikan bahwa penambahan aki dan natrium benzoate mampu meningkatkan kinerja biobaterai dari kulit nanas dan jumlah hari mempengaruhi kinerja dari biobaterai
Quantitative Caffeine Analysis in Robusta Coffee Utilizing Amperometric Biosensing Technology
Full text linkConsuming caffeine in inappropriate amounts can disrupt various aspects, especially health. Controlling intake by knowing the caffeine levels in coffee is necessary to reduce the potential negative impacts. This research focuses on the detection of caffeine in Robusta coffee at two different concentrations (1:10 and 1:20 g/mL) and its relationship with yeast metabolism. An amperometric biosensor with a transimpedance amplifier to measure caffeine levels is used which has the advantages of sensitivity, cost-effectiveness, real time monitoring, biocompatibility, and reliable measurements. The data were statistically analyzed using ANOVA and visualized using Principal Component Analysis (PCA). The results revealed a concentration -dependent decrease in biosensor readings as caffeine levels increased (0.1, 0.5, 1, 1.5, and 2 mM), indicating caffeine's ability to inhibit yeast oxygen consumption and oxygen-dependent metabolic processes. The sensitivity of the biosensor in detecting caffeine is 36.66 mV/mM. PCA uncovered complex patterns, relationships, and variations within the caffeine data. PC1 and PC2, the first two principal components, collectively explained 86.3% of the data's variance. Eigenvalues for both PCs were greater than 1, highlighting their significance in understanding the dataset's complexity. This research enhances our understanding of caffeine content in Robusta coffee and its effects on yeast metabolism, providing valuable insights for the coffee industry. This use of yeast biosensors offers efficiency, and adaptability that make that biosensor valuable in a variety of scientific and industrial contexts