Effect of Silica Addition on Mechanical Properties of Eggshell-Derived Hydroxyapatite

Eggshell is a solid waste that is available in abundance but is being left unused. Eggshell containing calcium in a high amount. Calcium can be used as a precursor for hydroxyapatite (HAp). Modification of HAp with SiO2 is expected to improve its low mechanical properties for biomedical applications. In this study, HAp is synthesized from the eggshell. Then, it was modified by adding SiO2 utilizing the coprecipitation method with concentrations of 10%, 20%, 30%, and 40%, respectively. The HAp and HAp/SiO2 were characterized using; X-ray diffraction and Fourier transform infrared spectroscopy. The analysis HAp and HAp/SiO2 were density, compressive strength, and hardness. The best mechanical properties of HAp/SiO2 were characterized using SEM-EDS. The HAp were prepared successfully with a ratio of Ca/P was 1.673, close to the theoretical 1.67. The addition of SiO2 caused a decrease in crystallite size and density but increased compressive strength and hardness. The best mechanical properties of HAp/SiO2 were obtained with SiO2 of 30% and 40% with similar values.

Overpressure-generating mechanisms in the Blok F3, North Sea, Netherland

Block F3 North Sea is a block with pore pressure values that vary over time due to complex geological conditions such as burial and various sedimentation zones. Pore pressure is one of the important aspects that need to be analyzed as a basis for the identification of zones and overpressure mechanisms. Overpressure is a greater pore pressure condition than normal pressure and may cause drilling problems, such as kicks, blowouts, etc. This study calculated pore pressure values using the eaton method approach with well data and seismic data. Both data are integrated for generating pore pressure values in 1D and 3D. 1D Modelling uses Interactive Petrophysics 3.5, while 3D modeling uses Petrel software. In 3D modeling, the variables used are interval velocity and inversion velocity obtained by acoustic impedance inversion. The sub-variables used are the inversion density and the regression density obtained from well density acoustic impedance inversion. The existence of a 1D overpressure zone at a depth of 1,100 – 1,800 m with an overpressure value of 3,836 – 18,975 kPa. In addition, the overpressure value based on the 3D model is 8,000 – 18,000 kPa. The overpressure zone is validated using an acoustic impedance inversion model with a high value of 5,200 – 5,380 (m/s)*(gr/cc). Overpressure in Block F3 is predicted to occur from disequilibrium compaction..

Accumulator-free Hough Transform for Sequence Collinear Points

The perception, localization, and navigation of its environment are essential for autonomous mobile robots and vehicles. For that reason, a 2D Laser rangefinder sensor is used popularly in mobile robot applications to measure the origin of the robot to its surrounding objects. The measurement data generated by the sensor is transmitted to the controller, where the data is processed by one or multiple suitable algorithms in several steps to extract the desired information. Universal Hough Transform (UHT) is one of the appropriate and popular algorithms to extract the primitive geometry such as straight line, which later will be used in the further step of data processing. However, the UHT has high computational complexity and requires the so-called accumulator array, which is less suitable for real-time applications where a high speed and low complexity computation is highly demanded. In this study, an Accumulator-free Hough Transform (AfHT) is proposed to reduce the computational complexity and eliminate the need for the accumulator array. The proposed algorithm is validated using the measurement data from a 2D laser scanner and compared to the standard Hough Transform. As a result, the extracted value of AfHT shows a good agreement with that of UHT but with a significant reduction in the complexity of the computation and the need for computer memory.

Flood Rate Assessment of the Woyla River Watershed, Aceh Province, Indonesia

This study aims to assess Flood susceptibility and flood hazard levels and obtain the distribution of hazard levels and flood hazards in the Woyla watershed, Aceh Province. This research design generally uses a descriptive survey method and divide into several stages, such as data collection, data processing, data presentation, and delivery of research results. Each determinant of flood-prone areas includes a land slope, altitude, soil texture, drainage, land cover, and rainfall, analyzed spatially utilizing a map. Furthermore, based on the map, the regions are described based on the values that have been divided into classes. The results showed that the level of flood vulnerability in the Woyla watershed was divided into five classes, namely; the non-vulnerable class with an area of 14.88 Ha / 0.01%, low prone with an area of 90,731.62 Ha / 35.45%, medium with an area of 57,120.35 Ha / 22.32%, high with an area of 44,918.15 Ha / 17.55%, and very high with an area of 63,151.72 Ha / 24.67%. Also obtained a map of the distribution of flood hazard areas, the Woyla watershed area is divided into five classes, namely; the very light class with an area of 179,146.15 Ha / 70.00%, mild with an area of 32,868.84 Ha / 12.84%, moderate with an area of 20,129.93 Ha / 7.87%, danger with an area of 6.007. 29 Ha / 2, 35%, and very dangerous with an area of 17,784.51 Ha / 6.95%. The level of flood vulnerability in the Woyla watershed is dominant in West Aceh Regency, which is in the very high and high category classes with a total area of 56,876.65 Ha and 23,527.40 Ha. Meanwhile, the level of flood hazard in the Woyla watershed is also more dominant in West Aceh Regency than falls into the most dangerous and dangerous class category with a total area of 17,784.51 Ha and 6,007.29 Ha. With the largest part in the very light class at the flood hazard level of 179,146.15 ha.

Use of Reactivated Spent FCC Catalyst as Adsorbent for Lead (II) Ions from Refinery-based Simulated Wastewater

Improper handling of wastewater from various industries causes environmental pollution. Hence, this study involved using a reactivated spent FCC catalyst, a cheap and reliable adsorbent for Pb2+ removal from refinery-based simulated wastewater. In contrast, response surface methodology (RSM) was used to determine the optimum operating condition. The adsorptive capacity of the reactivated spent FCC catalyst was observed using different parameters such as temperature, pH, adsorbent dosage, and contact time. At the end of the study, it was found that the optimum condition for removing Pb2+ was at pH of 7, adsorbent dose of 1.75 g, contact time of 75 mins, and temperature of 117 oC. At this condition, the maximum removal efficiency of Pb2+ was found to be 100 %. A quadratic model equation via central composite design under the RSM was developed to predict the Pb2+ removal from all the input parameters. Based on the F-statistic values, the temperature had the greatest influence on the removal of Pb2+ while adsorbent dosage and contact time were also significant.

Space Adequacy Analysis Based on Population Pressure National park Area (Case Study : Putri Betung Sub District, Gayo Lues, Aceh)

The land requirement for Putri Betung Sub District in Gunung Leuser National Park (GLNP) area kept increasing along with the population growth. The population density in the Putri Betung Sub-district was driven by the need for cultivation and residential area along the GLNP conservation boundary. This study aims to analyze the space adequacy for Putri Betung Sub-District in the GLNP area based on the population pressure prediction for 20 years. The research method was conducted by field survey using remote sensing, interviewed the residents, and analyzed the population pressure index using the Soemarwoto formula. The Population Pressure Index (PPI) for the cultivation area was determined from 13 villages in Putri Betung Subdistrict and shows that 12 villages had a PPI 1 value (population pressure was over the land carrying capacity limits). Only one village had PPI 1 (population pressure less than the land carrying capacity. Based on data surveys obtained, the cultivation area set in the Putri Betung area was no longer sufficient for population, resulting from the expansion in the GLNP area of 4,776.97 ha. Meanwhile, predictive analysis on space adequacy for people living decently in Putri Betung Sub District for 20 upcoming years is 6117.15 ha. In conclusion, 12 out of 13 villages in the Putri Betung SubDistrict have PPI 1 value, which is inversely proportional to the land carrying capacity. The PPI values could result in other pressures on the ecology and biodiversity conservation in National Park. It is suggested that the government need to surpass the pressure by making new policy on people’s resettlement, expanding the cultivation area, or shifting people's livelihoods

Combined Effect of Low and High Rate of Corrugated Steel Fiber and Stirrups on Mechanical Performance of SFSCC Beams

In order to improve the fragile nature of concrete, and its low tensile strength, and with a view to giving it the desired properties, which serve to build more durable structures at less cost, the association of a self-consolidating concrete with fiber, is considered a wise combination. However, given the limited amount of research on the response of SFSCC structures, designers and engineers do not use this material with confidence. In the present work, an experimental companion was conducted, in the interest of examining, the combined effect of fibers and stirrups include low and high rate of steel fiber, on the behavior of SFSCC beams. This choice allowed working on economically viable SFSCC. Beams were made also with ordinary concrete and others with self-consolidating. Thirty-six beams were of identical cross-section 10x20cm and length of 120cm; carried out with or without longitudinal and transverse reinforcement. Before proceeding with the main part of the research program, the concrete mixtures were characterized first in the fresh state by the following tests: Slump Flow, Time Flow T500; J-Ring, L-Box, V-Funnel and Sieve stability, and then in the hardened state: compressive and tensile strengths. In the light of the results obtained, it was found that adding steel fibers to fresh self-consolidating concrete decreased its workability and fluidity, but improved its hardening properties. Subsequently, the addition of the steel fibers increased the flexural capacity of the beams significantly, and improved their ductility. Also, an addition of the steel fibers in an adequate percentage, in this case at 0.9%, made it possible to replace the shear reinforcements, and can lead to changing the mode of failure from a collapse by brittle shear, to a mechanism of ruin in ductile bending.

The Implementation of Machine Learning in Lithofacies Classification using Multi Well Logs Data

Lithofacies classification is a process to identify rock lithology by indirect measurements. Usually, the classification is processed manually by an experienced geoscientist. This research presents an automated lithofacies classification using a machine learning method to increase computational power in shortening the lithofacies classification process's time consumption. The support vector machine (SVM) algorithm has been applied successfully to the Damar field, Indonesia. The machine learning input is various well-log data sets, e.g., gamma-ray, density, resistivity, neutron porosity, and effective porosity. Machine learning can classify seven lithofacies and depositional environments, including channel, bar sand, beach sand, carbonate, volcanic, and shale. The classification accuracy in the verification phase with trained lithofacies class data reached more than 90%, while the accuracy in the validation phase with beyond trained data reached 65%. The classified lithofacies then can be used as the input for describing lateral and vertical rock distribution patterns.

Bentonite and Magnetite Filler-Modified Polyurethane Foam in Fixed Bed Column for the Adsorption of Mercury(II) Ions from Aqueous Solution

This paper proposed adsorbent development by synthesizing polyurethane foam (PUF) using a simple method, mixing polyol with isocyanate and adding fillers of bentonite and magnetite to the PUF matrix. The study's main objective was to produce a PUF-based adsorbent with high reactivity to remove Hg2+ in wastewater. This bentonite and magnetite filler-modified polyurethane foam (BMPUF) adsorbent was fixed in a bed column for the adsorption of mercury (II) ions from an aqueous solution. The effect of initial Hg2+ concentration on the removal rate and the effect of contact time on adsorption efficiency was investigated. Langmuir, Freundlich, and BET non-linear models were taken into account to determine the best adsorption isotherm fitting and obtain adsorption capacity, intensity, and pore volume. As a result, it followed the non-linear Freundlich model, and the average adsorption capacity and intensity were 0.466 mg/g and 0.923, respectively. The average BET-based pore volume obtained was 0.782 L/mg. The kinetics study showed that the non-linear pseudo-first-order kinetics model was more suitable for describing the Hg2+ adsorption kinetics. The maximum equilibrium adsorption capacity was 1.770 mg/g with the adsorption rate of 0.0013 min-1 based on the non-linear model. The effect of varying bentonite and magnetite ratio on adsorption isotherm and kinetics was also investigated. Overall, the potential application of BMPUF adsorbent in the adsorption of mercury (II) ions was demonstrated in the current study.

Developing a Computer Simulation Game as a Training Tool for Mine Self-Escape in Underground Coal Mine

– Gaming technology has been growing these years rapidly. The game engines have the capability of creating a very realistic virtual environment model. This technology can also be used for mining purposes. In this research, the game engine is specifically used to develop a mine self-escape simulation game for training purposes. The game engine which is used to develop the simulation game is Unreal Engine 3. The main advantage of using such a simulation game as a training tool is because it allows the trainee to experience a dangerous situation while not being put in danger. This kind of training is considered better than conventional briefing, normally conducted by showing a video or pamphlet. Studies have shown that people retain more information when they are involved interactively in the learning process. In this research, a computer simulation game as a training tool for underground coal mine self-escaped has been successfully created using fire scenarios. The player/trainee should follow some procedures to get to the safety zone