Journal of Engineering and Technological Sciences
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A Coal Mine Underground Localization Algorithm Based on the Feature Vector
Get PDFTo enhance the position estimation accuracy of an underground localization system for coal mine roadways, an algorithm based on the feature vector of received signals is presented in this paper. The algorithm includes three steps: the construction process of a feature vector database and a distance database, the vector matching process and the localization process. When a signal vector is received, it only needs to calculate the distance from the received vector to the center vector of each subset and then compare it with the data in the distance database. After multiple filtering and comparing the source of the strongest signal, the coordinates closest to the received vector are found. The experiment showed that the maximum error of this algorithm was 4 m and the average error was 1.62 m. Furthermore, within a localization error of 1 m, the X-axis localization accuracy was 98% while the Y-axis localization accuracy was 86%. Also, the algorithm took much less time compared to the KNN and WKNN algorithms, so the algorithm meets the requirements of coal mine safety systems and underground personnel localization systems
Application of Fibonacci Sequence and Lucas Sequence on the Design of the Toilet Siphon Pipe Shape
Get PDFThe purpose of this study was to explore the method for designing the toilet siphon pipe shape to improve flushing performance. The Fibonacci sequence and the Lucas sequence were used to design the structural parameters of the siphon pipe. The flushing processes of the toilet were simulated using the computational fluid dynamics (CFD) method to analyze the flushing performance under different siphon pipe shapes. Experimental studies were conducted to verify the reliability of the simulation results. The results indicated that when the Lucas numbers and the Fibonacci numbers were utilized to regulate the curvature of the siphon pipe in the Xi direction and the Yj direction respectively, the flushing performance of the toilet was optimal. In order to obtain better flushing performance, the curvature of the siphon pipe should be smooth and have obvious transitions at the connections of different sections. When the overall size of the siphon pipe is kept constant, a short siphon pipe length is helpful for the improvement of toilet flushing performance
Effects of Grinding Process on the Properties of the Coal Bottom Ash and Cement Paste
Get PDFThe grinding process is necessary to convert original coal bottom ash (CBA) into a powder form. The aim of this study is to evaluate the grinding process effects on physical properties of CBA, it influences on consistency and setting time of cement paste and to predict it potentiality based on chemical characteristics to reduce the alkali-silica reaction (ASR) in concrete. The CBA is the by-product of coal based thermal power plant. Due to high production of electricity in Malaysia, the excess amount of CBA has been produced annually and it causes the environmental problems. Therefore, it is necessary to come up with advanced solutions for that pollution. This study considered the different grinding periods i.e. 2, 10, 20, and 40hrs as to produce different particle fineness. It was perceived through the laboratory findings that the more the grinding period, finer the particle sizes. Besides that, cement paste with 10, 20 and 30% of ground CBA as a substitute of ordinary portland cement (OPC) by weight was prepared, it was observed that the consistency of OPC paste increases with the addition of ground CBA. Moreover, initial and final setting time of cement paste containing ground CBA was observed higher than the OPC paste. Hence, based on experimental analysis and energy efficiency scenario, grinding period of 20hrs with specific surface area 3835.75 cm2/g is suggested for the future studies
Performance Enhancement by Using Wet Pad in Vapor Compression Cooling System
Get PDFVapor compression cooling systems are widely used in hot and dry climates where the atmospheric temperature in summer reaches around 48 °C and the relative humidity can be below 20%. These cooling systems normally use environmentally friendly gases that do not harm the ozone layer. These systems work with high gas pressure, which consumes high energy and leads to a low coefficient of performance when compared to cooling systems that do not use an environmentally friendly gas. Theoretical and experimental studies have been conducted to find a suitable solution for the performance improvement of this type of cooling system. A possible solution is to lower the temperature of the air before it enters the condenser of the compression cooling system by passing it through a wet pad. The water evaporates due to the latent heat that is withdrawn from the wet pad. The air temperature is reduced to about 11 °C before it enters the condenser of the compression cooling system. This enhancement increases the cooling capacity of the vapor compression cycle by nearly 20% and increases the coefficient of performance by 15%, in addition to reducing the consumed electricity up to 15%. In conclusion, the proposed method of adding a wet pad can significantly enhance the performance of the vapor compression cooling system
Gaussian Process Regression for Prediction of Sulfate Content in Lakes of China
Get PDFIn recent years, environmental pollution has become more and more serious, especially water pollution. In this study, the method of Gaussian process regression was used to build a prediction model for the sulphate content of lakes using several water quality variables as inputs. The sulphate content and other variable water quality data from 100 stations operated at lakes along the middle and lower reaches of the Yangtze River were used for developing the four models. The selected water quality data, consisting of water temperature, transparency, pH, dissolved oxygen conductivity, chlorophyll, total phosphorus, total nitrogen and ammonia nitrogen, were used as inputs for several different Gaussian process regression models. The experimental results showed that the Gaussian process regression model using an exponential kernel had the smallest prediction error. Its mean absolute error (MAE) of 5.0464 and root mean squared error (RMSE) of 7.269 were smaller than those of the other three Gaussian process regression models. By contrast, in the experiment, the model used in this study had a smaller error than linear regression, decision tree, support vector regression, Boosting trees, Bagging trees and other models, making it more suitable for prediction of the sulphate content in lakes. The method proposed in this paper can effectively predict the sulphate content in water, providing a new kind of auxiliary method for water detection
Physical Model of Vertical Water Movement Inside a Soil-Column Apparatus for Infiltration Study with A Two-Way Orientation Approach
Get PDFTo improve the theory of Richard's equation, studying infiltration under free-draining conditions at the ground surface is necessary. Verification is required to clarify the physical model of water movement. The aim of this study was to describe multistage measurements of both the wetting and the drying front scheme of one-dimensional infiltration at laboratory scale. A soil-column infiltration apparatus was built consisting of a double acrylic wall, a sensor set and a light bulb. Acrylic was chosen as the material for the wall to minimize possible heat conduction on the wall side, which was wrapped in double insulation to achieve adiabatic condition. The following three main sensors were used and controlled by a microcontroller: water-content, pressure and temperature sensors. Meanwhile, the light bulb at the top of the apparatus was set to non-isothermal condition. The instrument was successfully built to describe vertical water movement. Slight modifications were carried out to ensure more precise observation. This resulted in the initiating of new shape interpretation based on the water-ponding measurement to refine the simplified pattern that was introduced by the conventional Green-Ampt theory
Simulation of Void Detection System using Gamma-Ray Compton Scattering Technique
Get PDFA simple void detection system for concrete was successfully developed using high-penetration gamma rays with Compton scattering. This research attempted to identify a void in the subsurface of a concrete volume that could not be accessed from any of the sides. Monte Carlo simulation using GEANT4 toolkit was performed to investigate the gamma-ray backscattering events. An NaI(Tl) detector was used with 60Co and 137Cs as gamma-ray sources. The void's location was successfully detected during material target scanning. Density discrepancies conduce variance of the backscattering peak produced due to the presence of a void. Compared to 60Co as the gamma-ray source, 137Cs is a better choice for application in NDT systems using Compton scattering
Design of Elastomeric Bridge Bearing Pad Compound Formula Based on Hydrogenated Natural Rubber
Get PDFLaminated elastomeric bearing pad which is commonly produced by natural or chloroprene rubber is functioned as isolation system in bridge or flyover structures. In the research, hydrogenated natural rubber (HNR) was evaluated its feasibility to be used as base elastomer on steel-laminated bearing pad production by designing rubber compound formula. The compounding procedures of HNR applied various vulcanization system and carbon black filler types. The physical and mechanical tests result showed that only hardness parameter could fill the standar quality requirement of commercial elastomeric bearing pad as stated in AASHTO M251 in the range of 50 "“ 70 Shore A scale. The tensile property and compression set value of the HNR vulcanizates were under the requirement. This was due to low rubber-filler interaction and rigidity of crosslink network. The low interaction was more evident with increasing carbon filler particle size. By adjusting semi efficient vulcanization system and used N220 as carbon filler in designing compound formula,HNR was regarded as alternative promosing base elastomer for elastomeric bridge bearing pad manufacture. Nevertheless, it was necessary to improve the procedure to achieve better tesile property and compression set parameter
Finite Element Analysis of Reinforced Concrete Coupling Beams
Get PDFThe use of reinforced concrete coupling beams in high-rise buildings is popular, especially in seismic prone areas. The modeling of a reinforced concrete coupling beam in a commercial structural analysis software is usually simplified to a line element or a compound of concrete and steel rebar as fiber element. Hence, the analysis of the simplified model cannot capture the overall hysteretic behavior of the element. Moreover, the simplified model is also limited in its capacity to estimate the shear strength contributed by the concrete and diagonal bars, if any, respectively. This study used an advanced finite element analysis package to simulate the cyclic behavior of four coupling beam specimens available in the database. The results show that the hysteretic loop predicted by the finite element analysis tends to overestimate the maximum lateral load capacity. On the other hand, analytical evaluation of the shear strength contributed by concrete and diagonal bars showed good agreement with the test results