Taiwan Association of Engineering and Technology Innovation: E-Journals
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Effect of Volute Collector on the Performance of Centrifugal Pump Based on Entropy Generation Analysis
Get PDFA proper design of centrifugal pumps reduces power loss and improves efficiency. This study aims to investigate and analyze the effect of different volute collector configurations on centrifugal pump performance. Locations of losses are detected using the entropy production rate, whereas the number of losses is evaluated using user-defined codes. Three volute collectors are selected based on their connections with standard pipes. A steady flow numerical analysis is performed to determine the performance parameters of the centrifugal pump and select a modified volute collector design. Comparing the results of experiments on the base and modified volute collectors confirmed that the proper design of the volute collector can help reduce the secondary flow losses at subsequent locations, which reduces the entropy production and losses. As compared to the base pump, the modified volute collector improved the pump efficiency by 3% at the duty flow
A New 6D Chaotic Generator: Computer Modelling and Circuit Design
Get PDFThe objective of this study aims at using the Matlab-Simulink environment and the LabVIEW software environment to build computer models of a six-dimensional (6D) chaotic dynamic system. For the fixed system’s parameters, the spectrum of Lyapunov exponents and the Kaplan-York dimension are calculated. The presence of two positive Lyapunov exponents demonstrates the hyperchaotic behavior of the system. The fractional Kaplan-York dimension indicates the fractal structure of strange attractors. An active control method is extended to achieve global chaotic synchronization of two identical novel 6D chaotic systems with unknown system parameters. Based on the results obtained in Matlab-Simulink and LabVIEW models, a chaotic signal generator for the 6D chaotic system is implemented in the MultiSim environment. The experimental results show that the chaotic behavior simulation in the MultiSim environment is similar to those in the Matlab-Simulink and LabVIEW models. The simulation results demonstrate that the Pecora-Carroll method is a simple way of chaotic masking and signal decoding
Seismic Vulnerability Assessment for Various Shapes and Types of Reinforced Concrete Shear Walls in Multi-Storey Buildings
Get PDFTo improve the lateral stiffness and economy, reinforced concrete shear walls are introduced in buildings. This study aims to conduct the seismic assessment of shear walls in a multi-storey building. In this work, various factors are investigated and their performance is compared for various shapes and types of shear walls with respect to strength, displacement, time period, etc. The building considered for the study purpose is a G+12 residential building and is situated in a high seismic zone. The response spectrum analysis of the building is carried out by using the software ETABS. The results show that shear walls not only reduce the seismic forces in a building, but also are advantageous if they are situated in proper positions
Maintenance Initiation Prediction Incorporating Vibrations and System Availability
Get PDFAs per ISO-10816, electric motors up to 15 kW are classified as Class I machines, and the major reason for their failure is that the vibrations in them are above the alert limit. This study presents a new model for predicting the condition-based maintenance (CBM) initiation points through vibration measurement in a system of Class I machines. The proposed model follows the accelerated life testing (ALT) procedure. ALT includes the formation of an artificial wear environment in bearings to analyze the resultant system vibrations on system availability. The artificial wear environment created is close to the real industrial situation. The results show that the prediction of the CBM initiation points is based on the established relation between the system availability and vibrations. Furthermore, a relation between the available time for maintenance initiation and different vibration velocities is demonstrated
Theoretical Investigation for the Influence of Various Parameters on the Performance of a Novel Concentration-Based Solar Desalination System
Get PDFThis study aims to investigate the influence of various parameters on the freshwater yield and efficiency of a novel concentration-based solar desalination system. The system performance under the summer and winter climatic conditions of Rabat city, Morocco is evaluated. The design parameters are glass cover thickness, absorber basin thickness, brackish water mass, and absorber basin material. The climatic parameters are wind velocity, ambient temperature, and solar radiation. Numerical studies on different system parameters are done by examining the effect of system component parameters on the system performance. Through the MATLAB code, the equations for the freshwater yield and efficiency of the new system are constructed and solved. The results show that the system gives the best performance with 6 mm glass cover thickness, 2 mm absorber basin thickness, and 40 kg brackish water mass
An Image Synthesis Method Generating Underwater Images
Get PDFThe objective of this study is to convert normal aerial images into underwater images based on attenuation values for different water types by utilizing the image formation model (IFM) with Jerlov water types. Firstly, the depth values are derived from RGB-D images. If the depth information is not available, the values between 0.5 m to 10 m are chosen, and the transmission map is estimated by these values. Secondly, the statistical average background light values of Br = 0.6240, Bg = 0.805, and Bb = 0.7651 have been derived by analyzing 890 images using two methods, namely quad-tree decomposition and four-block division. Finally, the conversion of aerial-to-underwater images is done using the derived values, and the images are verified by computer simulation using MATLAB software. The result indicates that this method can easily generate underwater images from aerial images and makes it easier for the availability of ground truth
Investigation on Tribological Characteristics of Al 7075 MMNC: Behavior of Micro- and Nano-Sized Composites
Get PDFThis study investigates the mechanical properties and the wear behavior of Al 7075/Al2O3/SiCNP composites. The hybrid composites are manufactured using the stir casting technique. In this work, the Al 7075 alloy is reinforced with five different weight fractions of Al2O3 and a constant SiCNp, with an average particle size of 50 nm. The aluminum metal matrix composites are examined through surface morphology and X-ray diffraction (XRD) patterns to identify the material behavior. The material characteristics and the wear behavior of the metal composites are examined using a pin-on-disk test. Wear measurements are performed by varying loads, sliding speeds, and sliding distances. The results reveal that the composites reinforced with 4% of Al2O3 particulates exhibit superior properties. The wear rate and the coefficient of friction (COF) decrease with the increase in the reinforcement content
Evaluation of the Shapley Additive Explanation Technique for Ensemble Learning Methods
Get PDFThis study aims to explore the effectiveness of the Shapley additive explanation (SHAP) technique in developing a transparent, interpretable, and explainable ensemble method for heart disease diagnosis using random forest algorithms. Firstly, the features with high impact on the heart disease prediction are selected by SHAP using 1025 heart disease datasets, obtained from a publicly available Kaggle data repository. After that, the features which have the greatest influence on the heart disease prediction are used to develop an interpretable ensemble learning model to automate the heart disease diagnosis by employing the SHAP technique. Finally, the performance of the developed model is evaluated. The SHAP values are used to obtain better performance of heart disease diagnosis. The experimental result shows that 100% prediction accuracy is achieved with the developed model. In addition, the experiment shows that age, chest pain, and maximum heart rate have positive impact on the prediction outcome
Low Access Latency and High Throughput for Full-Duplex Cognitive Radio Using Mobility Caching Placement Strategy
Get PDFIn a remote framework, the densely allotted radio range is not effectively utilized by an authorized primary user, which limits a secondary user to avoid disturbance to a primary user while utilizing a channel. To solve the shortage problem of accessible range, this study proposes a mobility caching placement strategy (MCPS) based sliding window scheme to optimize the latency and throughput of cognitive radio system. The performance parameters of the proposed system are analyzed using energy detection metrics by considering full-duplex communication. By the MATLAB analysis and the evaluation with and without self-interference suppression, the results demonstrate that the entrance inactivity of the MCPS based sliding window is diminished by a factor of 1.9 as contrasted with the existing full-duplex systems. With the improved latency and throughput, the proposed method can avoid the ruinous impacts of drawn-out self-residual suppression more effectively compared to the existing approaches
Quantitative and Qualitative Characterization of Coatings Added to Low Voltage Switches
Get PDFElectroplating is one of the most important processes in the manufacturing of switches. Coating the conductive parts of switches improves their appearance and increases their durability, even in severe environments. This study proposes a non-destructive testing method to qualitatively and quantitatively characterize coatings added to the conductive parts of low voltage switches (contacts and terminals). The method is based on the injection of a high-frequency signal into a switch using the vector network analyzer (VNA). An in-depth analysis of the reflected signal is conducted to characterize the coatings. For the quantitative characterization, a comparison is made between switches that are plated with different coating thicknesses. As for the qualitative characterization, a comparison is made between switches that are manufactured with different types of metals. The results show that each switch type has an electromagnetic signature that varies according to the conductivity and the thickness of the metals used for coating