Through this paper we aim to measure a distance using an optical signal. The distance measurement is based on the time of the flight (TOF) method via correlation technique. A method of stretching the time scale is used to decrease the operating frequency. A proof of concept using Matlab results in a distance resolution less than 17mm. The algorithm is implemented on a standalone cheap digital signal controller and the measured results show high accuracy comparable to the simulated one. The optical transmitters and optical receivers are implemented using off shelf components.

Through this paper we aim to measure a distance using an optical signal. The distance measurement is based on the time of the flight (TOF) method via correlation technique. A method of stretching the time scale is used to decrease the operating frequency. A proof of concept using Matlab results in a distance resolution less than 17mm. The algorithm is implemented on a standalone cheap digital signal controller and the measured results show high accuracy comparable to the simulated one. The optical transmitters and optical receivers are implemented using off shelf components.

This paper deals with the important issue of the gaseous pollutants dispersion in the environmental flow within urban atmospheres including the products of on-ground agriculture fires. The paper presents an accurate and efficient semi-implicit pressure-based algorithm developed for solving numerically the conservation equations governing weakly compressible turbulent environmental flow of multicomponent fluid. An in-house CFD code has been developed to implement the numerical solution of the present algorithm. The code is an integrated one consisting of three main elements which are the pre-processor, the solver and the post-processor. This in-house CFD code undergoes a standard validation process, using six generic test cases simulating a steady-state environmental flow associated with gas flow from a ground point source under different flow conditions. A prerequisite verification of the code has been considered for successful validation. The detailed standard validation process was performed according to AIAA Guide by comparing the predicted results with measurements especially conducted for the present work in the test section of the Atmospheric Boundary Layer Wind Tunnel facility of Assiut University. The results showed good qualitative and quantitative agreements for the present in-house CFD code with the corresponding flow measurements. These agreements together with the satisfaction of the prerequisite verification insure a satisfactory validation of the present in-house CFD code.

This paper deals with the important issue of the gaseous pollutants dispersion in the environmental flow within urban atmospheres including the products of on-ground agriculture fires. The paper presents an accurate and efficient semi-implicit pressure-based algorithm developed for solving numerically the conservation equations governing weakly compressible turbulent environmental flow of multicomponent fluid. An in-house CFD code has been developed to implement the numerical solution of the present algorithm. The code is an integrated one consisting of three main elements which are the pre-processor, the solver and the post-processor. This in-house CFD code undergoes a standard validation process, using six generic test cases simulating a steady-state environmental flow associated with gas flow from a ground point source under different flow conditions. A prerequisite verification of the code has been considered for successful validation. The detailed standard validation process was performed according to AIAA Guide by comparing the predicted results with measurements especially conducted for the present work in the test section of the Atmospheric Boundary Layer Wind Tunnel facility of Assiut University. The results showed good qualitative and quantitative agreements for the present in-house CFD code with the corresponding flow measurements. These agreements together with the satisfaction of the prerequisite verification insure a satisfactory validation of the present in-house CFD code.

This paper deals with the important issue of the gaseous pollutants dispersion in the environmental flow within urban atmospheres including the products of on-ground agriculture fires. The paper presents an accurate and efficient semi-implicit pressure-based algorithm developed for solving numerically the conservation equations governing weakly compressible turbulent environmental flow of multicomponent fluid. An in-house CFD code has been developed to implement the numerical solution of the present algorithm. The code is an integrated one consisting of three main elements which are the pre-processor, the solver and the post-processor. This in-house CFD code undergoes a standard validation process, using six generic test cases simulating a steady-state environmental flow associated with gas flow from a ground point source under different flow conditions. A prerequisite verification of the code has been considered for successful validation. The detailed standard validation process was performed according to AIAA Guide by comparing the predicted results with measurements especially conducted for the present work in the test section of the Atmospheric Boundary Layer Wind Tunnel facility of Assiut University. The results showed good qualitative and quantitative agreements for the present in-house CFD code with the corresponding flow measurements. These agreements together with the satisfaction of the prerequisite verification insure a satisfactory validation of the present in-house CFD code.

The success of mining operation primarily is measured by safety and productivity. Rock slope stability is the major concern in open pit mines. Slope instability results in damage to equipment, injuries to personnel, disruption to mining operation and loss overall mine profitability. The objective of this study is to demonstrate a method to select the optimal slope angle related to three principal factors: safety, productivity and mining costs. Also, it aims to investigate the accuracy of numerical analysis using different element types and order. Therefore, series of two-dimensional elasto-plastic finite-element models has been constructed at various slope angles (e.g. 400, 450, 500, 550, 600, 650, and 700) and different element types (e.g. 3-noded triangle (T_3), 6-noded triangle (T_6), 4-noded quadrilateral (Q_4) and 8-noded quadrilateral (Q_8)). The results are presented, discussed and compared at various slope angles and element types in terms of critical strength reduction factor (CSRF) or its equivalent factor of safety (FOS), total rock slope displacement, mine production and mining costs. The results reveal that, the mine productivity increases as slope angle increases, however, slope stability deteriorates. Alternatively, the factor of safety (FOS) decreases as slope angle becomes steeper (e.g. minimum factor of safety is obtained at highest steep angle of 700). Despite of the increasing in computation time, the analysis shows that, the accuracy of the modelling increases when adopting high-order element types (e.g. 8-noded quadrilateral and 6-noded triangle elements).

The success of mining operation primarily is measured by safety and productivity. Rock slope stability is the major concern in open pit mines. Slope instability results in damage to equipment, injuries to personnel, disruption to mining operation and loss overall mine profitability. The objective of this study is to demonstrate a method to select the optimal slope angle related to three principal factors: safety, productivity and mining costs. Also, it aims to investigate the accuracy of numerical analysis using different element types and order. Therefore, series of two-dimensional elasto-plastic finite-element models has been constructed at various slope angles (e.g. 400, 450, 500, 550, 600, 650, and 700) and different element types (e.g. 3-noded triangle (T_3), 6-noded triangle (T_6), 4-noded quadrilateral (Q_4) and 8-noded quadrilateral (Q_8)). The results are presented, discussed and compared at various slope angles and element types in terms of critical strength reduction factor (CSRF) or its equivalent factor of safety (FOS), total rock slope displacement, mine production and mining costs. The results reveal that, the mine productivity increases as slope angle increases, however, slope stability deteriorates. Alternatively, the factor of safety (FOS) decreases as slope angle becomes steeper (e.g. minimum factor of safety is obtained at highest steep angle of 700). Despite of the increasing in computation time, the analysis shows that, the accuracy of the modelling increases when adopting high-order element types (e.g. 8-noded quadrilateral and 6-noded triangle elements).

The success of mining operation primarily is measured by safety and productivity. Rock slope stability is the major concern in open pit mines. Slope instability results in damage to equipment, injuries to personnel, disruption to mining operation and loss overall mine profitability. The objective of this study is to demonstrate a method to select the optimal slope angle related to three principal factors: safety, productivity and mining costs. Also, it aims to investigate the accuracy of numerical analysis using different element types and order. Therefore, series of two-dimensional elasto-plastic finite-element models has been constructed at various slope angles (e.g. 400, 450, 500, 550, 600, 650, and 700) and different element types (e.g. 3-noded triangle (T_3), 6-noded triangle (T_6), 4-noded quadrilateral (Q_4) and 8-noded quadrilateral (Q_8)). The results are presented, discussed and compared at various slope angles and element types in terms of critical strength reduction factor (CSRF) or its equivalent factor of safety (FOS), total rock slope displacement, mine production and mining costs. The results reveal that, the mine productivity increases as slope angle increases, however, slope stability deteriorates. Alternatively, the factor of safety (FOS) decreases as slope angle becomes steeper (e.g. minimum factor of safety is obtained at highest steep angle of 700). Despite of the increasing in computation time, the analysis shows that, the accuracy of the modelling increases when adopting high-order element types (e.g. 8-noded quadrilateral and 6-noded triangle elements).

Several factors have crucial impact on the serviceability of underground openings including: the quality of rock mass; the presence of rock joints and their geometrical properties; the state of in-situ stress ratio; the depth below surface and opening geometry. This paper only investigates the effect of two parameters on the stability of underground shallow tunnels, namely: the presence of rock joints in the rock mass matrix and the shape of the excavation. A series of two-dimensional elasto-plastic finite-element models has been constructed using rock-soil, RS2D, software. Consequently, parametric stability analysis has been conducted for three different tunnel shapes (e.g. circular, square and horseshoe) with/without joint inclusion. Four reference points have been assigned in the tunnel perimeter (e.g. back, sidewalls and floor) to monitor the state of stress-displacement in the rock mass around them. The results indicate that the weak performance of a tunnel opening occurs with a square-shaped opening and when joints exist in the rock mass. In addition, the normal stress along joints sharply drops in the vicinity of a tunnel opening. Moreover, the direction of shear stress is reversed. Thus, it causes inward shear displacement.

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