Aceh International Journal of Science and Technology
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Optimizing Mechanical Properties of Al6063 Aluminum Alloy through Silicon Weight Percent Variation and Heat Treatment at the Propeller Shaft Materials Casting
Full text linkShip propulsion relies significantly on the efficiency of its components, with the shaft propeller playing a pivotal role in navigating vessels through water. Traditionally constructed from steel, this study explores an unconventional approach by employing an Aluminum Alloy base material, specifically the 6063 alloy, for the propeller shaft model. The material's mechanical properties become a crucial focus, prompting a detailed investigation into the impact of silicon and magnesium elements through a meticulous heat treatment process. The experimental procedure involves heating the Al6063 alloy to 790C, transitioning to a completely liquid state, and subsequently incorporating silicon and magnesium at specific temperatures. The stirring process, executed with a mechanical stirrer, sets the stage for the alloy's casting into a mold under pressure. Post-casting, the propeller shaft undergoes a comprehensive heat treatment regimen, including solution treatment, quenching, and artificial aging. The study's findings showcase a remarkable reduction in porosity with increasing silicon elements, reaching its lowest point at 4% wt Silicon. Tensile tests demonstrate a direct correlation between silicon addition and increased stress values, with the highest stress observed at 4% wt Silicon. Concurrently, hardness values ascend proportionally with silicon inclusion, peaking at 4% wt Silicon. The thorough analysis presented here highlights the effectiveness of silicon elements in enhancing the mechanical characteristics of the shaft propeller made of aluminum alloy, which bodes well for future developments in ship propulsion technology
Phosphate Removal from Aqueous Solutions using Activated Carbon Derived from Nypa fruticans
Full text linkNypa fruticans (NF) waste which includes the empty fruit bunches and shells (NFW), frond (NFF) and leaflets (NFL) composes primarily of hemicellulose, cellulose and lignin, shows great potential as a raw material for activated carbon (AC). This study investigated the removal of phosphate from aqueous solutions using activated carbon derived from Nypa fruticans. The NFW, NFF and NFL was pyrolyzed and physically activated in a tube furnace. FTIR analysis revealed that the NFW-AC, NFF-AC and NFL-AC exhibited functional groups such as chemical functional group O-H, C-O-C, C-O, C=O, C-O and C-H stretching in hemicellulose, cellulose and lignin, which were associated with phosphate (PO4) adsorption. Among these, the NFW-AC showed the lowest transmittance and higher pore density. Adsorption experiments indicated a rapid initial adsorption within the first 5 min, followed by minimal changes until equilibrium was reached at 30 min. The NFW-AC showed the best performance with the highest efficiency (40.05%) and capacity (85.85 mg/g). Adsorption kinetics for all activated carbon were better described by the pseudo-second-order model, with highest capacities of 60.606 mg/g and adsorption rates of 0.0235 g/mgmin attributed to NFW-AC. The adsorption isotherms followed the Langmuir mode, yielding capacities of 60.606 mg/g, 31.546 mg/g and 8.1967 mg/g for the NFW-AC, NFF-AC, and NFL-AC, respectively. These findings demonstrated the potential of Nypa fruticans-based activated carbon for phosphate adsorptio
Comparing Nanofiltration and Ion Exchange for Reverse Osmosis Pretreatment in Industrial Water Treatment: A Techno-Economic Analysis
Full text linkWater softening is a crucial process in various industrial applications, and the selection of an appropriate system involves balancing technical efficiency, environmental impact, and economic considerations. This paper presents a comprehensive analysis of two prominent industrial water softening systems, Nanofiltration (NF) and Ion Exchanger (IX), through a multidimensional lens. The systems design and sizing were simulated with computer assistance, using the DuPonts WAVE Water Treatment Design Software version 1.82. The technical evaluation, based on simulations, revealed that IX outperformed NF in total hardness removal ( 99%) at the expense of a slight increase in Total Dissolved Solids (TDS). In contrast, NF demonstrated a superior ability to reduce TDS, albeit with lesser total hardness removal. Environmental considerations highlighted trade-offs, with NF generating higher wastewater volumes and IX producing wastewater with highly concentrated TDS, necessitating complex treatment processes. Economically, NF generally incurred higher Total Annual Costs (TAC) at lower total hardness concentrations, while IX became costlier at higher concentrations. A selection chart is introduced to aid decision-making based on economic considerations. This research offers valuable insights for industries seeking an optimal water softening solution, balancing technical efficiency, environmental impact, and economic considerations. The findings provide a nuanced understanding to guide system selection based on specific water quality requirements and economic constraints
Structural Health Monitoring by Identification Dynamic Properties and Load Rating Factor at Multi-span Prestressed Concrete Girder Bridge
Full text linkIt is crucial to perform routine bridge maintenance in order to evaluate the structure's current state. As a result, it is possible to guarantee that the bridge structure can offer services that are both comfortable and secure. The bridge structure being able to reach the service life as planned is another goal that can be accomplished. Visual inspection or the use of some currently popular sensors can be used to monitor the condition of the bridge. The dynamic properties of a structure including modal frequency and mode shape will be used to determine the structure's present and potential future conditions. Using a velocitymeter, vibration data collection is conducted as the first step. The next step is analyzing data to determine natural frequency. The fundamental frequency of the Tugu Suharto bridge structure in Semarang was determined to be 3.995 Hz. Future bridge structure condition monitoring can be done using frequency data and finite element model. The condition of bridge infrastructure in the future for one city is an important thing that must be considered. Some bridges are classified as structurally deficient, and many bridges are nearing the end of their design lives. The next generation of Semarang highway bridges is currently being designed and built, but existing bridges still need to be maintained through proper inspection and load rating. In order to incorporate structural modeling, instrumentation, and nondestructive testing into the design, construction, and management of bridges, this study proposes an objective load rating protocol. Using information gathered from structural health monitoring (SHM), a baseline structural model is developed and verified. The load rating factors of the bridge are then determined using the structural model under both real-condition and simulated damaged conditions
Microplastics in Landfill Environments: Distribution, Characteristics, and Risks from Gampong Jawa, Indonesia
Full text linkLandfills are generally considered the ultimate solution for waste management. However, the degradation process of plastic waste in landfills causes the release of microplastic particles into the surrounding environment and threatens human health. The distribution and properties of microplastics in four environment matrices, soil, leachate, river water, and well water surrounding the landfill, are examined in this study. Sampling was conducted at the inflow and outflow areas of the leachate ponds., The soil at the top (05 cm) and bottom (520 cm), upstream and downstream surface water adjacent to the landfill, and community wells within a radius of fewer than 700 meters from the landfill. Microplastic analysis used a gradual extraction method with saturated NaCl for density separation, 30% hydrogen peroxide for organic matter degradation, and 0.05 M FeSO4 as a catalyst. Physical character identification of microplastics using a microscope showed microplastic contamination at all study sites. The results showed an abundance of microplastics was found in well water samples (808 to 979 items/L), leachate (209 to 757 items/L), surface water (6.29 to 7.2 items/L), and soil (23,340 to 23,420 items/kg). Types of microplastics found consist of fragments, fibers, films, pellets, foam, and rods. The size of microplastics found ranged from 1.897 m to 1,642.79 m. Fourier Transform Infrared spectroscopy examination identified polyethylene terephthalate (PET) plastic compounds in soil and leachate materials. The high concentration of microplastics in well water indicates potential groundwater contamination from landfill activities that may impact the surrounding community. This study provides preliminary insights into how landfills may contribute to environmental microplastic contamination. It paves the way for further research to develop mitigation strategies
Subsurfaces Modeling Based on Integrated Geophysics Method to Identify Mineralization Zone In "X" Area, West Java, Indonesia
Full text linkRing of fire passes through Indonesia, causing the presence of abundant mineral resource potential. Potential minerals in Indonesia are formed by hydrothermal processes. One of the hydrothermal deposits is a high-sulfidation epithermal (HSE) deposit. The appropriate geophysical methods can be used to find potential mineral resources. The geomagnetic method can detect mineralization by analyzing the development of structural pattern control. Tilt derivative filters used in magnetic data can clarify anomalous boundaries, especially structural straightness boundaries. The analysis showed that the mineralized zone had a distribution of low susceptibility values of 0.0054 to -0.0178cgs. due to destructive magnetite minerals in the advanced argillic alteration zone. Tilt derivative analysis shows the shape of a low circular anomalous pattern that extends north-south towards the boundary of the left horizontal fault, which develops into a faulty fault complex as control of mineralization. The method integration produces an HSE precipitate conceptual model, in which the presence of alteration and mineralization is controlled by a left horizontal fault zone that forms a fault complex descending in it and develops into a northwest-southeast tension vein plating dipping opening as estimation of mineralized pathways in the "X" Region, West Java, Indonesia
Recycling of Disposable Face Mask: Experimental Studies on Different Types of Polymer Mixture
Full text linkThe COVID-19 pandemic has caused significant impacts on the environment since the use of disposable face masks leads to the accumulation of plastic waste. In this study, a two-step extrusion and injection molding was performed to manufacture polymer blends consisting of 80% used face mask and 20% fraction of one of these recycled polymer mixtures: polypropylene (PP), high-density polyethylene (HDPE), and PET. ASTM D256 standard was used to evaluate the mechanical properties of the resulting polymer blend materials, while the physical performance was assessed by analyzing the shrinkage. It was found that adding other polymeric mixtures could not enhance the mechanical properties of pure disposable face masks, as measured by the impact strength. However, incorporating the recycled polymer into the face mask mixture is revealed to decrease shrinkage. Observation of the morphology surface of the fracture impact specimen using a Scanning Electron Microscope (SEM) confirmed the less miscibility within the recycled polymer/face mask. The blend, which contains recycled PET, showed the lowest percentage of shrinkage. Taking advantage of its recyclability characteristic, this current work may provide an alternative approach for using the disposable face mask in low load-bearing applications
Utilization of Coal-Mining Mud as a Safe and Environmentally Friendly Building Material
Full text linkCoal-mining mud is one of the wastes that must be treated before being discharged into the environment. The mud contains a lot of heavy metals which have the potential to pollute the environment and endanger human health. On the other hand, the metal contents in the mud can be used as components to strengthen building materials such as brick. In this study, an investigation was carried out to check whether the risk of heavy metal contamination in the coal-mining mud can be minimized when the brick is produced. In addition, this study also tested whether the bricks produced from the utilization of the mud were strong enough to be used as construction materials. The results obtained indicate that metal contamination can be significantly minimized through the solidification process of brick products and is following the Indonesian national quality standards. This study also shows that even though the bricks meet the strength standard for the certain purpose applied in Indonesia, the utilization of coal-mining mud mixed with cement and sand was not sufficient to produce strong bricks even though the weight obtained was quite light
The Identification of River Flow Capacity using the HEC-RAS 1D Model: Case Study of Sringin River Downstreamdy of the Sringin River Downstream
No full textThe Sringin is a downstream river located in East Semarang. The Sringin River becomes the channel waste of the East Semarang district area. The Sringin River bank is surrounded by the Terboyo industrial area and settlement. The flood occurred in both areas, especially at Ngilir village, Genuk subdistrict. It is caused by low-capacity sedimentation channels and buildings occupying the channel body. The study aims to estimate flood discharge during repeat period 2, 5, 10, 25, 50, and 100 years on Sringin river downstream, analyze the capacity cross-section river, and identify the river water level profile when debit flowed with various period repeat flood. The hydrology calculation showed that flood discharge plans in the repeat period 2, 5, 10, 25, 50, and 100 years are 12.42; 16.67; 19.81; 30.7; 31.6; 33.22 m 3 /s. At the same time, the flow river capacity is 2.95 m/s in the upstream section and 15.52 m/s in the downstream section. Thus, floods occurred in some places when large discharges flowed. In period 2, the water level is about 1.0 to 1.5 meters. In more repeat periods, the level is higher. The conclusion is that the Sringin River cannot flow with perfect discharge, which exceeds its flow capacity
Pressure Drop Analysis of Turbine Housing Model with Circular Sliced Pipe for Micro Hydropower Generation
Full text linkEnergy independence is a government program aiming to meet society's energy needs evenly. Steps to increase energy independence in the new and renewable energy sector include hydro-energy generation. One of the important components of a hydro generator is the penstock pipe and turbine housing, which channels water and then pushes and drives (spins) the turbine with the flow of water to produce electrical energy. The turbine housing flow design innovation must provide a function as an optimal fluid conductor by minimizing the resistance that occurs when fluid flows towards the turbine housing and rotates the turbine optimally. The scope of this research includes analysis of the phenomenon of energy loss flowing in circular pipe slices in hydroelectric power plant turbine housings with influencing factors such as friction, turbulence, and flow resistance, as well as measuring the pressure drop in circular pipe slices. The model developed is a circular slice bend with angles of 180 degrees, 270 degrees, 360 degrees, and 450 degrees, taking into account the optimal curvature ratio (R/D) of 3.5. Based on previous research, 90-degree wedge bends with many slices (n_(90-degree)) 4 to 6 or 4 and pressure drop coefficient (C_(pd-th)) obtained 180-degree (0.333 0.200), 270-degree (0.445 0.277), 360-degree (0.527 0.339), 450-degree (0.587 0.390) with a bend length L, an elevation reduction angle and a 1.5D upstream-downstream elevation difference to avoid contact between the upstream and downstream bends. The results obtained from this research are the slice modules that can be used and the resistance coefficient values that arise from the slice modules. The more slices selected according to the angle of inclination chosen, the smoother the resulting circular bend shape and the lower the resistance value, but the work will be more difficult. The most optimal slice module is the number of slices that allow its implementation, and the resistance coefficient is small. By knowing the optimal resistance coefficient value, the resulting pressure drop can be predicted to maximize the thrust to rotate the turbine