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Early Age Strength of Development Ultra High-Performance Concrete Using Class-F Fly Ash and Local Materials for Repair
Get PDFUltra High-Performance Concrete (UHPC) is an innovative material for such repairs because of its superior mechanical properties, strength, crack resistance, and durability. However, its high production cost, primarily due to using materials like silica fume and cement, is a significant drawback. This study explores the feasibility of incorporating fly ash and local materials into UHPCs to reduce costs while maintaining or improving their performance. As a supplementary cementitious material, fly ash enhances the compressive strength and workability of UHPC. The addition of limestone further supports early-age strength and workability. By evaluating the mechanical properties and workability of modified UHPCs, this research demonstrates the economic viability and environmental benefits of structural repairs. The results indicate that this modification can effectively enhance the early-age strength of UHPC, making it suitable for use as a repair material. The evaluation of the mechanical properties and workability of the modified UHPC suggests that these alternative materials can maintain or even improve the performance of UHPC. Thus, this approach offers a more economically viable and environmentally friendly solution for structural repairs
Physicochemical Properties of Crude and Purified of Glucomannan Flours
Get PDFKonjac glucomannan (KGM) is a versatile polysaccharide extracted from Amorphophallus species tubers. Commonly, extracted crude porang flour still has some impurities which limits the application of utilizing the material. High purity of processed glucomannan flour could satisfy the demand of growing awareness of healthy diet and industrial scale production. In this study, the physicochemical properties of purified glucomannan flour compared with crude porang flour were investigated. Thermal stability of the purified flour was increased indicated by higher degradation temperature, which was revealed by Thermogravimetric Analysis (TGA). The structural characteristics were investigated by FTIR and X-ray Diffraction (XRD) analysis. In addition, Scanning Electron Microscopy (SEM) was conducted to study the morphology and grain size of crude and purified flours. The results revealed that purified glucomannan flour has better thermal stability, higher crystallinity, smaller granule size and significantly higher viscosity compared to crude flour
Skema Staggered Grid pada Persamaan Air Dangkal untuk Simulasi Aliran di Sekitar Pulau
Get PDFWake merupakan suatu pola gelombang pada permukaan air yang muncul akibat adanya pergerakan benda rigid. Pada penelitian ini, skema staggered grid orde dua digunakan untuk menyelesaikan persamaan air dangkal tak linier. Hasil yang didapat digunakan untuk mensimulasikan munculnya riak yang timbul akibat adanya arus yang menabrak pulau berbentuk lingkaran. Pada simulasi ini gaya-gaya luar yang diperhitungkan adalah gangguan angin, gaya gesek dengan dasar, dan efek turbulensi. Simulasi dilakukan dengan meniupkan angin pada ujunga kanal memanjang dengan sebuah pulau di dekat pangkalnya yang memicu aliran air. Untuk bilangan Reynold yang kecil, aliran air bersifat laminar dan membentuk pola halus di sekitar pulau. Bilangan Reynold merupakan perbandingan antara ketaklinieran dengan viskositas air. Untuk simulasi dengan bilangan Reynold yang besar, aliran menjadi tidak stabil dan memicu munculnya riak turbulen. Pusaran air tampak pada riak yang muncul di belakang pulau
Antiinflamasi Ekstrak Daun Trembesi (Samanea saman (Jacq.)Merr.) Terhadap Ekspresi Enzim Siklooksigenase-2 (COX-2)
Get PDFBackground: The cyclooxygenase-2 (COX-2) enzyme is the main source of prostanoids in inflammation and has various effects on nerve endings, blood vessels, and cells involved in inflammation. Trembesi leaves (Samanea summons (Jacq.) Merr.) are one of the herbal plants that have anti-inflammatory properties because it contains steroid compounds with high antioxidant capacity, active compounds of flavonoids, and tannins. With antioxidant activity and high flavonoid, trembesi leaf extract can act as an anti-inflammatory and influence the COX-2 enzymes and can cause pro-inflammatory effects. Objective : To discover the effect of trembesi leaf extract as an anti-inflammatory on COX-2 enzyme levels. Laboratory experimental method live with 30 (Rattus norvegicus) with 3 sample groups: the negative control group was CMC NA, and the treatment group was given trembesi leaf extract 100 mg/KgBW and a dose of 200 mg/KgBW. COX-2 expression was examined using the immunohistochemical staining method. Then do data analysis with normality test, homogeneity test, test Kruskal-Wallis, and test Mann Whitney. Results : Trembesi leaf extract at a dose of 100 mg/KgBW with a concentration of 12% had the effect of inhibiting COX-2 enzyme expression compared to the negative control group and the extract group at a dose of 200 mg/KgBW at a concentration of 12%. Conclusion : Trembesi leaf extract has an effect on reducing inflammation of the cyclooxygenase-2 (COX-2) enzyme
Short Circuit Analysis due to Reconfiguration of AC to DC Electric Power System on Tanker Ship with Hybrid Energy Source
Get PDFThe conventional AC electric power distribution system on ships has a higher impedance than the DC system, thus providing more significant distribution losses. Due to the enormous losses in the distribution system, a larger power output is required to balance the power required by the loads, and the losses occur on the line between the sources and the loads. Therefore, reconfiguring the power distribution to the DC system is promising. However, analysis in other aspects needs to be performed, including for short circuit current. In this research, power system simulator software is used to analyze the amount of fault current that contributes to each type of distribution. The simulation is performed under four ship operation modes, including sailing, maneuvering, at port, and cargo loading-unloading. The results of the simulation show that the short-circuit current can be significantly decreased after the reconfiguration of the system. A similar phenomenon has occurred in other operation modes. The short circuit value decreases around ten times in the DC system compared to the AC system. Therefore, the DC system is safer than the AC system
Analysis of Sling Tension on the Lifting Process of Riser Support Jacket on Installation Phase
Get PDFThe increasing exploration and exploitation of oil and gas in the deep sea has led to an increasing need for new technologies to support these activities. In this study, a riser support structure in the form of a jacket is used to support the riser so that the stress can be minimized. Like the jacket structure in general, this riser support structure can be installed using various methods, including the lifting method. This study discusses the stress in the sling when the lifting process is carried out. The crane barge used in this study was first modeled using MOSES Software to determine how the barge moves when the lifting process is carried out. The result of the barge movement analysis is a Response Amplitude Operator (RAO). In the sway, heave and roll movements, it is known that the maximum value is at 90° heading, while in other movements, it varies. The riser support structure is modeled using SACS Software to determine the center of gravity, then the sling length is calculated. From the calculation, the sling length at lifting point 1 is 34,10 m, lifting point 2 is 34,14 m, lifting point 3 is 36,08 m, and lifting point 4 is 36,10 m. The lifting model is input into the OrcaFlex Software to analyze the sling stress. The analysis was performed in five loading directions, namely 0°, 45°, 90°, 135°, and 180°. The maximum stress occurs in the loading direction of 90°, with the result that sling 1 is 1932,70 kN, sling 2 is 1905,65 kN, sling 3 is 1161,64, and sling 4 is 1193,65 kN
Railway track width gauge performance review: evaluation of test results and their implications for safety improvement
Get PDFThe deteriorated state of the railway line poses operational risks for railway transportation due to potential safety concerns. The train derailment occurred because of an abnormal track width that was not immediately repaired. This improvement was omitted because of the absence of an accurate and real-time track width measurement tool. Several gauge have been widely developed. The measuring instrument developed uses an LMP (Linear Motion Position) sensor to measure the width of the path. The measuring mechanism connects the LMP shaft to a roller bearing arm that can move linearly and dynamically according to the groove width of the path. The linear movement of the roller bearing with the arm connected to the LMP shaft is converted as a change in the path width. To determine the function and measurement results of the measuring instrument, measurement experiments were conducted at Sidotopo stations (lines 5 and 6). Line 5 was chosen because of the straight area of the money order needle, the parallel crossing groove, and the curve. Line 6 was chosen because there is a gongsol path. Measurements on each path are made twice with the starting point and opposite direction. The measurement data are shown in the form of a width graph to the distance with one red line as the tolerance limit for widening the width of the line (1074 mm) and one blue line as the tolerance limit for narrowing the width of the line (1065 mm). The measurement results show the consistency of the measurement results. The largest measured width condition is 1092 mm, and the smallest measured width condition is 1058 mm.
Analyzing the Performance of Reverse Osmosis Membranes After the Cleaning Process: Case study Performed at PT. XYZ.
Get PDFPT. XYZ uses a reverse osmosis (RO) system in demin water treatment. One of the weaknesses of the RO system is the formation of fouling on the membrane, which can reduce the performance of the membrane, so it is necessary to carry out an appropriate cleaning process to remove deposits on the surface of the membrane, restore the separation characteristics, and restore the normal capacity of the system. This research aims to examine the effect of cleaning on the performance of reverse osmosis membranes in the PT. XYZ with requirements for reverse osmosis membrane type FILMTEC BW30–400 IG. The research was conducted for 8 weeks by collecting data on the reverse osmosis control box and control room in the form of product flow rate, feed conductivity, and product conductivity. Based on the results of the study, it can be concluded that the effect of cleaning on membrane performance can only extend the life of the membrane and cannot meet the specifications for the working parameters of the reverse osmosis membrane, which can be seen in the salt rejection, salt passage, and flux values obtained in this study
Urban Drainage System Simulation Using 1D Model, Case Study: North Kembangan Drainage System, Jakarta
Get PDFJakarta has a high level of urbanization, which causes land use changes and increasing inundation problems. One area that has experienced inundation is North Kembangan with a height of 20 - 30 cm in recent years and so of that the location is included in flood-prone sub-districts. Accordingly, a study is needed to estimate the North Kembangan drainage system actual conditions using the rainfall-runoff transformation model. This study simulates using the Storm Water Management Model (SWMM), and the calibration validation process is accomplished using the Nash-Sutcliffe model efficiency coefficient (NSE) and root mean square error (RMSE) method to evaluate the reliability of the model. The calibration for several model parameters is required to obtain the reliability model, including the channel Manning coefficient, land overflow Manning coefficient, and curve number. The calibration result shows that NSE values are 0,65, and the RMSE is 0,051 based on data in 2021. Then the validation result shows the NSE is 0,62 and RMSE is 0,040 based on data in 2022