Taiwan Association of Engineering and Technology Innovation: E-Journals
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Assessing the Performance of Melted Plastic as a Replacement for Sand in Paving Block
Get PDFPlastic waste generates numerous environmental problems, such as garbage accumulation and plastic waste pollution in the oceans. This study aims to evaluate the effectiveness of melted plastic waste as a substitute material in paving blocks. The melted low-density polyethylene (LDPE) plastic is used as the cemented agent in the paving block. After melting, the melted LDPE plastic is mixed thoroughly with sand immediately and forms a paving block mold. The effectiveness of melted plastic as a bonding agent is evaluated based on the parameters of compressive strength, water absorption, and wear resistance. The results show that paving blocks with a melted plastic of 10% reach the required level of 9.39 MPa for the park. Hence, using melted plastic in paving blocks can be an alternative strategy to reduce plastic waste
A Co-Planar Waveguide Ultra-Wideband Antenna for Ambient Wi-Fi RF Power Transmission and Energy Harvesting Applications
Get PDFThis study proposes an ultra-wideband antenna for ambient radio frequency (RF) energy harvesting applications. The antenna is based on a co-planar waveguide (CPW) transmission line and incorporates a rectangular slot as an antenna harvester. The proposed antenna utilizes an evolutionary design process to achieve impedance matching of the 50 Ω CPW feeding line over the desired frequency bands. A parametric study investigates CPW elements and rectangular slot size. The harvester antenna is then connected to the primary rectifier circuit of the voltage doubler to examine the signal characteristics. The antenna covers the Industry, Science, and Medicine (ISM) Wi-Fi bands of 2.45 GHz and 5 GHz, achieving a realized gain of 3.641 dBi and 4.644 dBi at 2.45 GHz and 5 GHz, respectively. It exhibits a relatively broad frequency ranging from 2.16 GHz to 6.32 GHz, covering the ultra-wideband fractional bandwidth (FBW) of 105%
A 2D GaAs-Based Photonic Crystal Biosensor for Malaria Detection
Get PDFGallium arsenide (GaAs) composite semi-conductive rods with an air background lattice act as the building blocks for the photonic crystal structure used of a biosensor. The study presents a biosensor of a two-rod nano-cavity for identifying distinct stages of plasmodium falciparum in red blood cells (RBCs) in the early detection of malaria. The proposed biosensor enables the creation of a label-free biosensing environment in which optical and dispersion properties are investigated using plane wave expansion (PWE) and finite-difference time-domain (FDTD) techniques. The biosensor, with a sensing region for an analyte, is utilized to detect a change in refractive index to differentiate between normal RBCs and plasmodium falciparum-infected cells. The results show that the biosensor has a high sensitivity of 798.143 nm/RIU, a high Q-factor of 9881.926, a low detection limit (δ) of 222.4 × 10-6 RIU, a high FOM of 4496.079 RIU-1, and a compact area of 46.14 µm2
State Estimation and Optimal Control of Four-Tank System with Stochastic Approximation Approach
Get PDFThis study aims to optimally control the level of a four-tank system at the steady state in the random disturbance environment using the stochastic approximation (SA) approach. Firstly, the stochastic optimal control problem of an equivalent discrete-time is introduced, where the voltages to the pumps are the control inputs. By minimizing the sum of squared errors, the liquid levels are estimated. Then, first-order necessary conditions are derived by defining the Hamiltonian function. Thus, the optimal voltages are calculated based on the estimated liquid levels to update the gradient of the cost function. Finally, for illustration, parameters in the system are considered and a simulation is conducted. The simulation results show that the state estimation and control law design can perform well, and the liquid levels are addressed along the steady state. In conclusion, the applicability of the SA approach for handling a four-tank system with random disturbances is demonstrated
Innovative Steel Pennon Plate-Headed Stud of Shear Connectors for Composite Structures
Get PDFThis study proposes an innovative pennon plate-headed stud of shear connectors. The proposed stud consists of two triangular-shaped steel plates on both sides of the headed stud; it is expected to increase the shear capacity of a steel-concrete composite connection. Nonlinear finite element analysis is carried out using ABAQUS to analyze the response of 54 models of PPH studs. A full factorial design and the analysis of variance are employed in the design of experiments (DOE). The impacts of factors and their interactions, such as the thickness and height of the pennon plates, concrete grades, and stud diameters, are captured by using 33 × 21 DOE with a 5% significance level. The results show that the ultimate shear resistance is increased apparently. Additionally, the concrete grade and stud diameter significantly influence the capacity of the connection. Moreover, connection slip is greatly affected by concrete grade, the height of the plate, and the interaction between plate thickness and height
Modeling and Forecasting Urban Sprawl in Sylhet Sadar Using Remote Sensing Data
Get PDFForecasting urban sprawl is important for land-use and transport planning. The aim of this study is to model and predict the future urban sprawl in Sylhet Sadar using remote sensing data. The ordinary least square (OLS) regression model and the geographic information system (GIS) are used for modeling urban expansion. The model is calibrated for the years 2014 to 2017 using eight explanatory variables extracted from the regression model. The regression coefficients of the variables are found statistically significant at a 99% confidence level. The cellular automata (CA) model is then used to analyze, model, and simulate the land-use and land-cover (LULC) changes by incorporating the algorithm of logistic regression (LR). The calibrated model is used to predict the 2020 map, and the result shows that the predicted map and the actual map of 2020 are well agreed. By using the calibrated model, the simulated prediction map of 2035 shows an urban cell expansion of 220% between 2020 and 2035
On the Performance Analysis and Environmental Impact of Concrete with Coal Fly Ash and Bottom Ash
Get PDFCoal is a commonly used fuel by coal power plants that produce coal fly ash and coal bottom ash (coal FABA) as byproducts. The latest regulation in Indonesia changes coal FABA classification to non-toxic waste, which opens up its utilization possibility. This paper analyses the coal FABA potential from Suralaya Coal Power Plant as concrete material and its environmental impact. To determine coal FABA potential, the methods used in this paper are slump test, compressive strength test, flexural strength test, and carbon footprint calculation. This paper shows that concrete mixture with coal FABA content has a lower slump value, lower compressive strength, and generally lower flexural strength. Furthermore, the carbon footprint calculation result shows that concrete mixture with coal FABA content has lower CO2 emissions than conventional concrete. Finally, the result shows that concrete with coal FABA could be used as non-structural concrete
Metallurgical Characterization of SS 316L Repurposed by Wire Plus Arc Additive Manufacturing
Get PDFThis research aims to analyze the microstructures and mechanical characteristics of stainless steel (SS) 316L repurposed by wire plus arc additive manufacturing (WAAM). The SS 316L wire is deposited on a SS 316 substrate, which can be repurposed. This deposited material underwent optical microscopy, X-ray diffraction, and tensile test, and the results indicate that it features cellular and columnar dendrites at the bottom and equiaxial grains at the top. The tensile strength of the interface region between the deposited material (DM) and the base material (BM) is the highest (559 ± 4.16 MPa vs. 510 ± 4.93 MPa in DM and 540 ± 2.65 in BM), indicating that the BM and the deposited layers are strongly bonded. All the results from the defect observation, microstructures, and mechanical characteristics confirm the potential of the WAAM process for repurposing
Effect of Organic Loading Rates on Performance of Treating Dairy Wastewater in a Lab-Scale Sequencing Batch Reactor
Get PDFThis study aims to investigate, the effect of organic loading rates (OLRs), nutrient ratio addition, and sludge retention time (SRT) on treating dairy wastewater in a sequencing batch reactor (SBR) system. This investigation is verified by experiments conducted in 3 phases at 3 different OLRs (1.8, 1.2, and 0.9 kg/m3d, respectively). Urea ((NH2)2CO) is added to make a suitable (COD:N:P) ratio of (100:5:1) in dairy wastewater. The SRT is adjusted from 50 days to an appropriate value of 18 days. The obtained results show that the COD, TN, and TP removal efficiencies are increased with decreasing OLRs. Sludge concentration in the SBR tank is stable at 1100 mg/L after adding (NH2)2CO. In addition, the SBR operated at a suitable SRT (i.e. 18 days) helps the biomass stably, resulting in enhancement of COD, TN, and TP removal. The results are helpful to the design of SBR for treating dairy wastewater
Electronically Tunable Voltage-Mode Multiphase Sinusoidal Oscillator with Low Output Impedance Nodes Employing VD-DIBAs
Get PDFThe multiphase sinusoidal oscillator (MSO) is useful for various electrical and electronic applications. This study aims to design an MSO employing voltage differencing differential input buffered amplifiers (VD-DIBAs). The design procedure is based on cascading the first-order low-pass filter. Each phase consists of a VD-DIBA, two resistors, and a grounded capacitor. An odd-phase system without requiring an additional amplifier. The frequency is electronically controlled through the bias current without affecting the condition. The sinewave amplitudes and the phase difference between each waveform are identical. The proposed MSO is designed to obtain three-phase waveforms (n = 3). PSPICE simulation demonstrates the performance of the proposed oscillator with 0.18 μm TSMC CMOS parameters with ±0.9 V power supply. The feasibility of the proposed MSO is also verified with experiments using the VD-DIBA constructed from commercial integrated circuits (ICs) with a ±5 V power supply. The simulated and experimental results align with theoretical predictions