This paper takes the propagation characteristics of heavy metals and the judgment of the location of pollution sources as the research objects, aiming to analyze the propagation characteristics of different heavy metals. Firstly, the Gaussian diffusion model is conducted to establish the propagation characteristics model of heavy metal pollutants in the atmosphere. Then, based on the law of conservation of mass and the law of two-dimensional diffusion, the two-dimensional diffusion model is adopted to establish the propagation characteristics model of heavy metals in soil moisture. According to these two models, the nonlinear differential equations are established respectively, revealing that the characteristics of the two propagation ways are related to space, time, diffusion coefficients, and other factors. Then, in the light of the propagation characteristics of different heavy metals, the least square method is applied to reduce the data calculation error and obtain the specific location of the pollution source. Finally, through establishing the three-dimensional diffusion model of heavy metal diffusion by introducing artificial control, speed and angle of prevailing wind direction, and other factors, the model is further optimized. The establishment of this model provides an important theoretical basis and guiding significance for the future study of heavy metal pollutants.
This paper takes the propagation characteristics of heavy metals and the judgment of the location of pollution
sources as the research objects, aiming to analyze the propagation characteristics of different he avy metals. Firstly,
the Gaussian diffusion model is conducted to establish the propagation characteristics model of heavy metal
pollutants in the atmosphere. Then, based on the law of conservation of mass and the law of two -dimensional
diffusion, the two-dimensional diffusion model is adopted to establish the propagation characteristics model of
heavy metals in soil moisture. According to these two models, the nonlinear differential equations are established
respectively, revealing that the characteristics of the two propagation ways are related to space, time, diffusion
coefficients, and other factors. Then, in the light of the propagation characteristics of different heavy metals, the least
square method is applied to reduce the data calculation error and obtain the specific location of the pollution source.
Finally, through establishing the three-dimensional diffusion model of heavy metal diffusion by introducing artificial
control, speed and angle of prevailing wind direction, and other factors, the mode l is further optimized. The
establishment of this model provides an important theoretical basis and guiding significance for the future study of
heavy metal pollutants.
Buried Natural Gas Pipe Line Leakage – Quantifying Methane Release and Disper...CFD LAB
The methane into the soil from buried natural gas pipelines due to small leakages, changes the soil properties, posing potential risks to humans and the environment. It is essential to estimate the leakage rate and monitor the methane diffusion range outside the pipeline, which is challenging due to the presence of soil. The main contribution of this work is to bridge the gap between estimating the leakage rate of underground pipelines and predicting the diffusion behaviors through calculating the gas concentration in the soil. The quantified leakage rate estimation model for air was firstly established by experimental results and validated by the numerical results, which were further modified by the methane with the numerical simulations. The methane diffusion model in the soil was then performed, through which, the influencing factors were explained and validated. In addition, the methane release and dispersion results in the soil could be used as the boundary conditions of the gas diffusion model in the air. The results show that the quantifying estimation correlations can predict the leakage rate and dispersion range in the soil accurately with errors less than 7.2 % and 15 %, respectively. Moreover, the quantified relations have been validated by the full-field experiments. And, the dispersion behaviors in the air could be portrayed instead of being regarded as a jet flow.
This document summarizes research on improving the flotation of ultrafine particles smaller than 0.08mm. It proposes using smaller air bubbles in turbulent flow to increase collision probability between particles and bubbles. A mathematical model is described showing that concentration of particles decreases exponentially with flow distance as particles coagulate with bubbles. Experimental results show a new flotation machine using this approach concentrates over 90% of lead in under 1m3/h, demonstrating effectiveness for extracting ultrafine particles.
Effect of Turbulence Model in Numerical Simulation of Single Round Jet at Low...ijceronline
Single axi-symmetric round jet flow was analyzed using computational techniques and validated with experimental results to establish the suitable turbulence model for simulation of low Reynolds number jets exiting from fully developed pipe. This work is performed as an initial study before computationally simulating multiple impinging jets. To this end a single round jet at Reynolds number of 7500 exiting from a fully developed pipe and entering into stationary air was modeled. Velocity and turbulence profiles were extracted from the simulation and validated with in-house experimental results. It was observed that although all the four turbulence models studied were able to closely predict the mean velocity field, they were not able to accurately predict the turbulence intensity distributions. From the models studied, it was concluded that SST k- ω model was the best turbulence model for simulating low Reynolds number jet flow exiting from fully developed pipe.
THEORETICAL STUDY ON PIPE OF TAPERED THICKNESS WITH AN INTERNAL FLOW TO ESTIM...IAEME Publication
This research study the effect of tapered thickness on the free transverse vibration of clamped – free pipe which have uniform circular cross section conveying water by using Raighly –Ritz method in the two case, the first involves the pipe have a constant wall thickness (t1) at clamped end equal to (1mm & 2mm) while the thickness (t2) at free end changes according to the ratio (t2/t1=0.2, 0.4, 0.6, 0.8, 1). In the second case the thickness at free end (t2) is constant (1mm & 2mm) whereas the thickness at clamped end (t1) changes at ratio (t1/t2=0.2, 0.4, 0.6, 0.8, 1). The pipe has a constant inner radius (Ri) of (1 cm or 2 cm) and different values of length (1m & 2m).
IRJET- Numerical Analysis of Slurry Flow Characteristics Through Horizontal P...IRJET Journal
This document summarizes a numerical study of slurry flow characteristics in a horizontal pipeline using computational fluid dynamics (CFD). The study models the flow of particles 0.125 mm in size and 2.47 specific gravity through a 4m long, 54.9 mm diameter pipe. Simulations were conducted at velocities of 2 m/s and 5 m/s and particle concentrations of 30% and 40% to analyze solid concentration distribution, velocity distribution, and pressure drop. An Eulerian two-phase model with RNG k-epsilon turbulence modeling was used to simulate the solid-liquid flow and solve the governing equations throughout the computational domain.
technoloTwo dimensional numerical simulation of the combined heat transfer in...ijmech
A numerical investigation was conducted to analyze the flow field and heat transfer characteristics in a vertical channel withradiation and blowing from the wall. Hydrodynamic behaviour and heat transfer results are obtained by the solution of the complete Navier–Stokesand energy equations using a control volume finite element method. Turbulent flow with "Low Reynolds Spalart-Allmaras Turbulence Model" and radiation with "Discrete Transfer Radiation Method" had been modeled. In order to have a complete survey, this article has a wide range of study in different domains including velocity profiles at different locations, turbulent viscosity, shear stress, suctioned mass flow rate in different magnitude of the input
Rayleigh number, blowing Reynoldsnumber, radiation parameter, Prandtl number, the ratio of length to width and also ratio of opening thickness to width of the channel. In addition, effects of variation in any of the above non-dimensional numbers on parameters of the flow are clearly illustrated. At the end resultants had been compared with experimental data which demonstrated that in the present study, results have a great accuracy, relative errors are very small and the curve portraits are in a great
agreement with real experiments.
This paper takes the propagation characteristics of heavy metals and the judgment of the location of pollution
sources as the research objects, aiming to analyze the propagation characteristics of different he avy metals. Firstly,
the Gaussian diffusion model is conducted to establish the propagation characteristics model of heavy metal
pollutants in the atmosphere. Then, based on the law of conservation of mass and the law of two -dimensional
diffusion, the two-dimensional diffusion model is adopted to establish the propagation characteristics model of
heavy metals in soil moisture. According to these two models, the nonlinear differential equations are established
respectively, revealing that the characteristics of the two propagation ways are related to space, time, diffusion
coefficients, and other factors. Then, in the light of the propagation characteristics of different heavy metals, the least
square method is applied to reduce the data calculation error and obtain the specific location of the pollution source.
Finally, through establishing the three-dimensional diffusion model of heavy metal diffusion by introducing artificial
control, speed and angle of prevailing wind direction, and other factors, the mode l is further optimized. The
establishment of this model provides an important theoretical basis and guiding significance for the future study of
heavy metal pollutants.
Buried Natural Gas Pipe Line Leakage – Quantifying Methane Release and Disper...CFD LAB
The methane into the soil from buried natural gas pipelines due to small leakages, changes the soil properties, posing potential risks to humans and the environment. It is essential to estimate the leakage rate and monitor the methane diffusion range outside the pipeline, which is challenging due to the presence of soil. The main contribution of this work is to bridge the gap between estimating the leakage rate of underground pipelines and predicting the diffusion behaviors through calculating the gas concentration in the soil. The quantified leakage rate estimation model for air was firstly established by experimental results and validated by the numerical results, which were further modified by the methane with the numerical simulations. The methane diffusion model in the soil was then performed, through which, the influencing factors were explained and validated. In addition, the methane release and dispersion results in the soil could be used as the boundary conditions of the gas diffusion model in the air. The results show that the quantifying estimation correlations can predict the leakage rate and dispersion range in the soil accurately with errors less than 7.2 % and 15 %, respectively. Moreover, the quantified relations have been validated by the full-field experiments. And, the dispersion behaviors in the air could be portrayed instead of being regarded as a jet flow.
This document summarizes research on improving the flotation of ultrafine particles smaller than 0.08mm. It proposes using smaller air bubbles in turbulent flow to increase collision probability between particles and bubbles. A mathematical model is described showing that concentration of particles decreases exponentially with flow distance as particles coagulate with bubbles. Experimental results show a new flotation machine using this approach concentrates over 90% of lead in under 1m3/h, demonstrating effectiveness for extracting ultrafine particles.
Effect of Turbulence Model in Numerical Simulation of Single Round Jet at Low...ijceronline
Single axi-symmetric round jet flow was analyzed using computational techniques and validated with experimental results to establish the suitable turbulence model for simulation of low Reynolds number jets exiting from fully developed pipe. This work is performed as an initial study before computationally simulating multiple impinging jets. To this end a single round jet at Reynolds number of 7500 exiting from a fully developed pipe and entering into stationary air was modeled. Velocity and turbulence profiles were extracted from the simulation and validated with in-house experimental results. It was observed that although all the four turbulence models studied were able to closely predict the mean velocity field, they were not able to accurately predict the turbulence intensity distributions. From the models studied, it was concluded that SST k- ω model was the best turbulence model for simulating low Reynolds number jet flow exiting from fully developed pipe.
THEORETICAL STUDY ON PIPE OF TAPERED THICKNESS WITH AN INTERNAL FLOW TO ESTIM...IAEME Publication
This research study the effect of tapered thickness on the free transverse vibration of clamped – free pipe which have uniform circular cross section conveying water by using Raighly –Ritz method in the two case, the first involves the pipe have a constant wall thickness (t1) at clamped end equal to (1mm & 2mm) while the thickness (t2) at free end changes according to the ratio (t2/t1=0.2, 0.4, 0.6, 0.8, 1). In the second case the thickness at free end (t2) is constant (1mm & 2mm) whereas the thickness at clamped end (t1) changes at ratio (t1/t2=0.2, 0.4, 0.6, 0.8, 1). The pipe has a constant inner radius (Ri) of (1 cm or 2 cm) and different values of length (1m & 2m).
IRJET- Numerical Analysis of Slurry Flow Characteristics Through Horizontal P...IRJET Journal
This document summarizes a numerical study of slurry flow characteristics in a horizontal pipeline using computational fluid dynamics (CFD). The study models the flow of particles 0.125 mm in size and 2.47 specific gravity through a 4m long, 54.9 mm diameter pipe. Simulations were conducted at velocities of 2 m/s and 5 m/s and particle concentrations of 30% and 40% to analyze solid concentration distribution, velocity distribution, and pressure drop. An Eulerian two-phase model with RNG k-epsilon turbulence modeling was used to simulate the solid-liquid flow and solve the governing equations throughout the computational domain.
technoloTwo dimensional numerical simulation of the combined heat transfer in...ijmech
A numerical investigation was conducted to analyze the flow field and heat transfer characteristics in a vertical channel withradiation and blowing from the wall. Hydrodynamic behaviour and heat transfer results are obtained by the solution of the complete Navier–Stokesand energy equations using a control volume finite element method. Turbulent flow with "Low Reynolds Spalart-Allmaras Turbulence Model" and radiation with "Discrete Transfer Radiation Method" had been modeled. In order to have a complete survey, this article has a wide range of study in different domains including velocity profiles at different locations, turbulent viscosity, shear stress, suctioned mass flow rate in different magnitude of the input
Rayleigh number, blowing Reynoldsnumber, radiation parameter, Prandtl number, the ratio of length to width and also ratio of opening thickness to width of the channel. In addition, effects of variation in any of the above non-dimensional numbers on parameters of the flow are clearly illustrated. At the end resultants had been compared with experimental data which demonstrated that in the present study, results have a great accuracy, relative errors are very small and the curve portraits are in a great
agreement with real experiments.
In this paper, linear graphical method, moment method and inverse function method are first applied in the laboratory test of one dimensional sand column device, determining the longitudinal dispersion coefficient. The longitudinal dispersions for five groups of sand taken from 20cm below the ground surface in the Oil Refinery of China Petroleum Ningxia Filial are obtained. On this basis, the problems within the calculation process when the three kinds of methods are applied into actual data were discussed. It can be readily concluded that the three values of dispersion coefficients are approximate, and the errors caused by the subjective factors of artificial mapping and numerical reading were avoided. The inverse function method is recommended to apply for the high accuracy, sample calculation process, less known conditions and better linearity.
Asme2009 82287 - Porous Media - Forced Convection FlowHIIO
In this study the flow field and heat transfer properties of a
steady, two-dimensional flow field in a porous domain between
two parallel plates is investigated numerically by using a
discretized numeric code. Analysis has been carried for
Reynolds number based on particle sizes ranging from 60 to
1000. Numerical results are compared with different numerical
methods used for predicting this kind of flow. Results are
obtained for different regime, various p Re numbers and the
effect of Particles size is also investigated. Solutions indicate
that by increasing the
p Re , the flow in the porous media
remains laminar where the flow has turbulence characteristics
for p Re <50. Moreover, by increasing p Re , the value of
average Nusselt number increases. Also, reducing the particle
size affects the Nusselt number and it increases while the
porosity remains the same.
This document summarizes a study that used lattice Boltzmann methods to simulate fluid flow through porous media. The study varied the Darcy number from 10-6 to 10-2 and the Reynolds number at 10 and 100 to observe their effects. Velocity profiles and streamline plots were produced from the simulations. Decreasing the Darcy number, which represents permeability, was found to significantly influence the flow properties and location of primary vortices within the porous media. The numerical simulations agreed well with existing theories on incompressible fluid flow.
Investigation of the Effect of Nanoparticles Mean Diameter on Turbulent Mixed...A Behzadmehr
Abstract
Turbulent mixed convection of a nanofluid (water/Al2O3, Φ=.02) has been studied numerically. Two-phase
mixture model has been used to investigate the effects of nanoparticles mean diameter on the flow parameters. Nanoparticles distribution at the tube cross section shows that the particles are uniformly dispersed. The non-uniformity of the particles distribution occurs in the case of large nanoparticles and/or high value of the Grashof numbers. The study of particle size effect showed that the effective Nusselt number and turbulent intensity increases with the decreased of particle size.
Mesoscopic simulation of incompressible fluid flow in porous mediaeSAT Journals
Abstract
Lattice Boltzmann method is used to simulate cavity driven fluid flow in porous media. A square cavity is considered with the top
lid moving with uniform velocity and other sides kept stationary. Simulation is carried out for values of Darcy number ranging
from 10-6 to10-2 at Reynolds number 10 and 100. Influence of Darcy number and Reynolds number is investigated on velocity
profiles and the streamline plots. Half-way bounce back boundary conditions are employed in the numerical simulation. The
numerical code is first verified with the results available in the literature and then used to simulate the Newtonian fluid flow in
porous media. The Darcy number and the Reynolds number were observed to have great influence on the flow properties and the
location of the primary vortex. Simulation was carried out for a 100100 mesh grid and a fine agreement is established theories
in incompressible fluid flow.
Keywords: Lattice Boltzmann method, incompressible flow, porous media
This document discusses convective mass transfer and mass transfer coefficients. It defines convective mass transfer as the rapid transfer of mass that occurs when there is motion in the transfer medium compared to the slower process of molecular diffusion. Mass transfer coefficients are introduced to simplify calculations of mass transfer rates. Different types of mass transfer coefficients are presented based on whether they are used for gases or liquids, and whether they are expressed in terms of concentrations, mole fractions, or partial pressures. Approximations for typical values of mass transfer coefficients in gas and liquid phases are provided.
This computational fluid dynamics study used simulations to analyze the effect of bend radius on erosion magnitude and location in an S-bend pipe carrying gas-solid or liquid-solid flows. Simulations were run for air velocities of 15.24-45.72 m/s and water velocities of 0.1-10 m/s, with particle sizes of 50-300 microns and bend radius to pipe diameter ratios (r/D) of 1.5, 2.5, and 3.5. Maximum erosion was found at certain velocity-particle size combinations and occurred at specific angle locations within each bend. The simulations aim to provide insight on erosion behavior to inform pipe design and operating conditions.
This chapter introduces miniaturized devices that have become important for industrial applications in fields like chemical engineering, electronics cooling, automotive, aerospace, and biomedical. Transport processes in these devices are laminar due to small scales, resulting in poor mixing and heat/mass transfer. Additional mechanisms are needed to enhance transfer rates, like Dean vortices in tortuous channels. Multiphase flow also enhances mixing and rates. While single-phase flow can be predicted by macroscale correlations, multiphase flow in microchannels is not well understood. Taylor and annular flows, which occur over wide ranges of conditions, are important but heat transfer in Taylor flow is poorly understood and annular flow in microchannels is almost unstud
On Similarity of Differential Capacity and Capillary Pressure FractalKhalid Al-Khidir
On Similarity of Differential Capacity and Capillary Pressure Fractal Dimensions for Characterizing Shajara Reservoirs of the Permo-Carboniferous Shajara Formation, Saudi Arabia
Number of moles fractal dimensions for characterizing shajara reservoirs of t...Khalid Al-Khidir
This document summarizes a research article that calculates fractal dimensions from the relationship between number of moles, maximum number of moles, and wetting phase saturation in sandstone samples from the Shajara Formation in Saudi Arabia. Porosity was measured on samples and permeability was derived from capillary pressure data. Two equations were used to calculate fractal dimensions from number of moles and from capillary pressure relationships. Results showed similarity between the two fractal dimensions. Samples with a wide range of pore radii had higher fractal dimensions, reflecting greater connectivity and ability to accommodate more moles. The formation was divided into three reservoir units based on fractal dimensions. Higher fractal dimensions indicated higher heterogeneity and permeability, characterizing better reservoirs
CALIBRATION OF VEHICLE EMISSIONS-SPEED RELATIONSHIPS FOR THE GREATER CAIRO ROADSIAEME Publication
The air pollution in Cairo is a matter of serious concern. The air pollution in greater Cairo is more than 10 to 100 times of acceptable world standards. There is a wide range of speed variation in Cairo. Consequentially, there is a wide range of emission rates. This research explains the relationship between vehicle speed and emissions for small cars using field tests. The representative car in this research is the Daewoo Lanus model 2000. This car is a representative for most small modern cars in Egypt. The mobile emission detector has been fixed on the car emission source. Tests have been implemented in two roads: Salah Salem road and Auto strad road. More than 1000 readings have been taken from the detector at various speeds. The speed varied between 0 and 85 km per hour and the relationships between speed and four types of emissions have been studied
This document discusses gas chromatography (GC), which separates compounds that can be vaporized without decomposing. It has two types depending on the stationary phase: gas-solid chromatography (GSC) and gas-liquid chromatography (GLC). The distribution of analytes between phases is expressed by the distribution constant K. Plate theory and rate theory, including the Van Deemter equation, are presented to describe column efficiency and factors influencing peak broadening such as eddy diffusion, longitudinal diffusion, and mass transfer under non-equilibrium conditions.
Presentation given by Sai Gu of Cranfield University on "Computational Modelling and Optimization of Carbon Capture Reactors" at the UKCCSRC Gas CCS Meeting, University of Sussex, 25 June 2014
This document summarizes work on modeling the dispersion of carbon dioxide (CO2) from accidental pipeline releases. It describes integrating models of in-pipe flow, the near-field release, and far-field dispersion to simulate a realistic industrial release scenario. Experimental data was used to validate the models. Decision support tools were developed to assess hazards by examining vapor concentrations and population densities. The work demonstrated feasibility in simulating industrially-relevant CO2 pipeline releases through integrated multi-scale modeling and highlighted areas for further development.
Electro kinetic fractal dimension for characterizing shajara reservoirs of th...Khalid Al-Khidir
This document summarizes a study that calculated fractal dimensions from electro kinetic and capillary pressure measurements on sandstone samples from the Shajara Formation in Saudi Arabia. The study divided the Shajara reservoirs into three units based on field observations: Lower, Middle, and Upper Shajara. Fractal dimensions were calculated for samples from each unit using two methods: 1) the relationship between electro kinetic coefficient, maximum electro kinetic coefficient, and saturation, and 2) the relationship between capillary pressure and saturation. Higher fractal dimensions, indicating more heterogeneous and permeable reservoirs, were found for samples with a wider range of pore sizes and more interconnected pores. The fractal dimensions from the two measurement methods showed good agreement.
CFD investigation of coal gasification: Effect of particle sizeIRJET Journal
This document presents a computational fluid dynamics (CFD) investigation of the effect of coal particle size on coal gasification in a fluidized bed. The CFD model uses Eulerian-Eulerian two-fluid modeling approach with kinetic theory of granular flow to simulate gas-solid flow behavior. Simulations were performed with two particle sizes - 0.00062 m and 0.001 m - at fluidization velocities ranging from 0.16 to 1 m/s. The results show that smaller particle size leads to better solid distribution, easier generation of bubbles, and faster fluidization. At high velocities, particle size has little effect other than on bed height expansion. The study provides insights into how particle size impacts hydrodynamics in fluid
The document describes an experiment on removing CO2 from air using a countercurrent rotating packed bed. Key findings include:
- A rotating packed bed was designed to absorb CO2, where the liquid and gas flow countercurrently under centrifugal force. This compact design improves mass transfer efficiency.
- Experiments investigated the effect of parameters like rotational speed, gas and liquid flow rates, and MEA solution concentration on the height of transfer unit (HTU) for CO2 absorption.
- HTU values for CO2 absorption ranged from 2.4 to 4 cm depending on the above parameters. Faster rotational speeds improved mass transfer and lowered HTU.
Liquid chromatography still striving for high efficiency2guest63ff7d
This document discusses approaches to improve the efficiency of liquid chromatography (LC). It summarizes that existing approaches include high temperature LC, monolithic stationary phases, fused-core particles, and sub-2-micron totally porous particles. Each approach aims to reduce band broadening and mass transfer resistance through various means like increased flow rates, reduced diffusion distances, or improved permeability. However, each also has limitations such as potential thermal or chemical degradation, limited stability, or very high back pressures. Overall miniaturization and smaller particle sizes indicate the future direction of LC development towards higher efficiency separations.
The sound velocities in dense fluids from distribution functionsArezoo Azaripour
1. The article evaluates sound velocities and adiabatic compressibilities in dense fluids using three known analytical expressions for radial distribution functions (RDFs).
2. To calculate these properties, the expressions must present RDF as a function of interparticle distance, density, and temperature.
3. The results are compared to experimental data for argon and an accurate analytic equation of state for the Lennard-Jones fluid. Using RDF expressions tests their ability to predict sound velocities and compressibilities, and identifies better expressions.
Mathematical model for an area source and the point source in an urban areaeSAT Journals
1) A mathematical model was developed to study the dispersion of pollutants emitted from an area source and a point source on the boundary in an urban area.
2) The model was solved numerically using the implicit Crank-Nicolson finite difference method. Results showed that pollutant concentration was less upwind of the heat island center and more downwind, and was higher near the ground surface and point source.
3) Concentration magnitudes were higher under stable atmospheric conditions compared to neutral conditions. The model took into account mesoscale winds, chemical reactions, deposition, and other removal mechanisms.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
In this paper, linear graphical method, moment method and inverse function method are first applied in the laboratory test of one dimensional sand column device, determining the longitudinal dispersion coefficient. The longitudinal dispersions for five groups of sand taken from 20cm below the ground surface in the Oil Refinery of China Petroleum Ningxia Filial are obtained. On this basis, the problems within the calculation process when the three kinds of methods are applied into actual data were discussed. It can be readily concluded that the three values of dispersion coefficients are approximate, and the errors caused by the subjective factors of artificial mapping and numerical reading were avoided. The inverse function method is recommended to apply for the high accuracy, sample calculation process, less known conditions and better linearity.
Asme2009 82287 - Porous Media - Forced Convection FlowHIIO
In this study the flow field and heat transfer properties of a
steady, two-dimensional flow field in a porous domain between
two parallel plates is investigated numerically by using a
discretized numeric code. Analysis has been carried for
Reynolds number based on particle sizes ranging from 60 to
1000. Numerical results are compared with different numerical
methods used for predicting this kind of flow. Results are
obtained for different regime, various p Re numbers and the
effect of Particles size is also investigated. Solutions indicate
that by increasing the
p Re , the flow in the porous media
remains laminar where the flow has turbulence characteristics
for p Re <50. Moreover, by increasing p Re , the value of
average Nusselt number increases. Also, reducing the particle
size affects the Nusselt number and it increases while the
porosity remains the same.
This document summarizes a study that used lattice Boltzmann methods to simulate fluid flow through porous media. The study varied the Darcy number from 10-6 to 10-2 and the Reynolds number at 10 and 100 to observe their effects. Velocity profiles and streamline plots were produced from the simulations. Decreasing the Darcy number, which represents permeability, was found to significantly influence the flow properties and location of primary vortices within the porous media. The numerical simulations agreed well with existing theories on incompressible fluid flow.
Investigation of the Effect of Nanoparticles Mean Diameter on Turbulent Mixed...A Behzadmehr
Abstract
Turbulent mixed convection of a nanofluid (water/Al2O3, Φ=.02) has been studied numerically. Two-phase
mixture model has been used to investigate the effects of nanoparticles mean diameter on the flow parameters. Nanoparticles distribution at the tube cross section shows that the particles are uniformly dispersed. The non-uniformity of the particles distribution occurs in the case of large nanoparticles and/or high value of the Grashof numbers. The study of particle size effect showed that the effective Nusselt number and turbulent intensity increases with the decreased of particle size.
Mesoscopic simulation of incompressible fluid flow in porous mediaeSAT Journals
Abstract
Lattice Boltzmann method is used to simulate cavity driven fluid flow in porous media. A square cavity is considered with the top
lid moving with uniform velocity and other sides kept stationary. Simulation is carried out for values of Darcy number ranging
from 10-6 to10-2 at Reynolds number 10 and 100. Influence of Darcy number and Reynolds number is investigated on velocity
profiles and the streamline plots. Half-way bounce back boundary conditions are employed in the numerical simulation. The
numerical code is first verified with the results available in the literature and then used to simulate the Newtonian fluid flow in
porous media. The Darcy number and the Reynolds number were observed to have great influence on the flow properties and the
location of the primary vortex. Simulation was carried out for a 100100 mesh grid and a fine agreement is established theories
in incompressible fluid flow.
Keywords: Lattice Boltzmann method, incompressible flow, porous media
This document discusses convective mass transfer and mass transfer coefficients. It defines convective mass transfer as the rapid transfer of mass that occurs when there is motion in the transfer medium compared to the slower process of molecular diffusion. Mass transfer coefficients are introduced to simplify calculations of mass transfer rates. Different types of mass transfer coefficients are presented based on whether they are used for gases or liquids, and whether they are expressed in terms of concentrations, mole fractions, or partial pressures. Approximations for typical values of mass transfer coefficients in gas and liquid phases are provided.
This computational fluid dynamics study used simulations to analyze the effect of bend radius on erosion magnitude and location in an S-bend pipe carrying gas-solid or liquid-solid flows. Simulations were run for air velocities of 15.24-45.72 m/s and water velocities of 0.1-10 m/s, with particle sizes of 50-300 microns and bend radius to pipe diameter ratios (r/D) of 1.5, 2.5, and 3.5. Maximum erosion was found at certain velocity-particle size combinations and occurred at specific angle locations within each bend. The simulations aim to provide insight on erosion behavior to inform pipe design and operating conditions.
This chapter introduces miniaturized devices that have become important for industrial applications in fields like chemical engineering, electronics cooling, automotive, aerospace, and biomedical. Transport processes in these devices are laminar due to small scales, resulting in poor mixing and heat/mass transfer. Additional mechanisms are needed to enhance transfer rates, like Dean vortices in tortuous channels. Multiphase flow also enhances mixing and rates. While single-phase flow can be predicted by macroscale correlations, multiphase flow in microchannels is not well understood. Taylor and annular flows, which occur over wide ranges of conditions, are important but heat transfer in Taylor flow is poorly understood and annular flow in microchannels is almost unstud
On Similarity of Differential Capacity and Capillary Pressure FractalKhalid Al-Khidir
On Similarity of Differential Capacity and Capillary Pressure Fractal Dimensions for Characterizing Shajara Reservoirs of the Permo-Carboniferous Shajara Formation, Saudi Arabia
Number of moles fractal dimensions for characterizing shajara reservoirs of t...Khalid Al-Khidir
This document summarizes a research article that calculates fractal dimensions from the relationship between number of moles, maximum number of moles, and wetting phase saturation in sandstone samples from the Shajara Formation in Saudi Arabia. Porosity was measured on samples and permeability was derived from capillary pressure data. Two equations were used to calculate fractal dimensions from number of moles and from capillary pressure relationships. Results showed similarity between the two fractal dimensions. Samples with a wide range of pore radii had higher fractal dimensions, reflecting greater connectivity and ability to accommodate more moles. The formation was divided into three reservoir units based on fractal dimensions. Higher fractal dimensions indicated higher heterogeneity and permeability, characterizing better reservoirs
CALIBRATION OF VEHICLE EMISSIONS-SPEED RELATIONSHIPS FOR THE GREATER CAIRO ROADSIAEME Publication
The air pollution in Cairo is a matter of serious concern. The air pollution in greater Cairo is more than 10 to 100 times of acceptable world standards. There is a wide range of speed variation in Cairo. Consequentially, there is a wide range of emission rates. This research explains the relationship between vehicle speed and emissions for small cars using field tests. The representative car in this research is the Daewoo Lanus model 2000. This car is a representative for most small modern cars in Egypt. The mobile emission detector has been fixed on the car emission source. Tests have been implemented in two roads: Salah Salem road and Auto strad road. More than 1000 readings have been taken from the detector at various speeds. The speed varied between 0 and 85 km per hour and the relationships between speed and four types of emissions have been studied
This document discusses gas chromatography (GC), which separates compounds that can be vaporized without decomposing. It has two types depending on the stationary phase: gas-solid chromatography (GSC) and gas-liquid chromatography (GLC). The distribution of analytes between phases is expressed by the distribution constant K. Plate theory and rate theory, including the Van Deemter equation, are presented to describe column efficiency and factors influencing peak broadening such as eddy diffusion, longitudinal diffusion, and mass transfer under non-equilibrium conditions.
Presentation given by Sai Gu of Cranfield University on "Computational Modelling and Optimization of Carbon Capture Reactors" at the UKCCSRC Gas CCS Meeting, University of Sussex, 25 June 2014
This document summarizes work on modeling the dispersion of carbon dioxide (CO2) from accidental pipeline releases. It describes integrating models of in-pipe flow, the near-field release, and far-field dispersion to simulate a realistic industrial release scenario. Experimental data was used to validate the models. Decision support tools were developed to assess hazards by examining vapor concentrations and population densities. The work demonstrated feasibility in simulating industrially-relevant CO2 pipeline releases through integrated multi-scale modeling and highlighted areas for further development.
Electro kinetic fractal dimension for characterizing shajara reservoirs of th...Khalid Al-Khidir
This document summarizes a study that calculated fractal dimensions from electro kinetic and capillary pressure measurements on sandstone samples from the Shajara Formation in Saudi Arabia. The study divided the Shajara reservoirs into three units based on field observations: Lower, Middle, and Upper Shajara. Fractal dimensions were calculated for samples from each unit using two methods: 1) the relationship between electro kinetic coefficient, maximum electro kinetic coefficient, and saturation, and 2) the relationship between capillary pressure and saturation. Higher fractal dimensions, indicating more heterogeneous and permeable reservoirs, were found for samples with a wider range of pore sizes and more interconnected pores. The fractal dimensions from the two measurement methods showed good agreement.
CFD investigation of coal gasification: Effect of particle sizeIRJET Journal
This document presents a computational fluid dynamics (CFD) investigation of the effect of coal particle size on coal gasification in a fluidized bed. The CFD model uses Eulerian-Eulerian two-fluid modeling approach with kinetic theory of granular flow to simulate gas-solid flow behavior. Simulations were performed with two particle sizes - 0.00062 m and 0.001 m - at fluidization velocities ranging from 0.16 to 1 m/s. The results show that smaller particle size leads to better solid distribution, easier generation of bubbles, and faster fluidization. At high velocities, particle size has little effect other than on bed height expansion. The study provides insights into how particle size impacts hydrodynamics in fluid
The document describes an experiment on removing CO2 from air using a countercurrent rotating packed bed. Key findings include:
- A rotating packed bed was designed to absorb CO2, where the liquid and gas flow countercurrently under centrifugal force. This compact design improves mass transfer efficiency.
- Experiments investigated the effect of parameters like rotational speed, gas and liquid flow rates, and MEA solution concentration on the height of transfer unit (HTU) for CO2 absorption.
- HTU values for CO2 absorption ranged from 2.4 to 4 cm depending on the above parameters. Faster rotational speeds improved mass transfer and lowered HTU.
Liquid chromatography still striving for high efficiency2guest63ff7d
This document discusses approaches to improve the efficiency of liquid chromatography (LC). It summarizes that existing approaches include high temperature LC, monolithic stationary phases, fused-core particles, and sub-2-micron totally porous particles. Each approach aims to reduce band broadening and mass transfer resistance through various means like increased flow rates, reduced diffusion distances, or improved permeability. However, each also has limitations such as potential thermal or chemical degradation, limited stability, or very high back pressures. Overall miniaturization and smaller particle sizes indicate the future direction of LC development towards higher efficiency separations.
The sound velocities in dense fluids from distribution functionsArezoo Azaripour
1. The article evaluates sound velocities and adiabatic compressibilities in dense fluids using three known analytical expressions for radial distribution functions (RDFs).
2. To calculate these properties, the expressions must present RDF as a function of interparticle distance, density, and temperature.
3. The results are compared to experimental data for argon and an accurate analytic equation of state for the Lennard-Jones fluid. Using RDF expressions tests their ability to predict sound velocities and compressibilities, and identifies better expressions.
Mathematical model for an area source and the point source in an urban areaeSAT Journals
1) A mathematical model was developed to study the dispersion of pollutants emitted from an area source and a point source on the boundary in an urban area.
2) The model was solved numerically using the implicit Crank-Nicolson finite difference method. Results showed that pollutant concentration was less upwind of the heat island center and more downwind, and was higher near the ground surface and point source.
3) Concentration magnitudes were higher under stable atmospheric conditions compared to neutral conditions. The model took into account mesoscale winds, chemical reactions, deposition, and other removal mechanisms.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Annual atmospheric corrosion rate and dose-response function for carbon steel...Carlos Arroyave
This paper presents an assessment on the behavior of plain carbon steel exposure to the atmosphere of Bogotá. The main climate and environmental parameters, including relative humidity (RH), temperature (T), sulphur dioxide deposition (DSO2) and particulate matter deposition (DPM) were measured. Furthermore, mass loss of AISI/SAE 1006 plain carbon steel coupons was measured along one year. In this case, coupons were exposed in eight test sites located across the city of Bogotá. Results show that the corrosion rate of carbon steel is less than 35 μm yr–1 after one year. It was found that the west part of the city has the greatest aggressivity, which has the highest levels of DPM and DSO2, related with the characteristics of the anthropogenic activities distribution across the city. A dose-response function of plain carbon steel exposure to the atmosphere of Bogotá, based on RH, T and DSO2, was obtained.
This document provides an overview of airflow in acid-generating waste rock dumps. There are three main mechanisms of airflow - diffusion, convection, and barometric pumping. Diffusion transports oxygen through concentration gradients but is limited to shallow depths. Convection occurs due to thermal or pressure gradients and can transport oxygen deeper. Barometric pumping moves air in response to atmospheric pressure changes. Understanding airflow is important to control acid rock drainage generation from waste rock.
Receptor function and response of semiconductor gas sensorSherry Huang
Theoretical approaches to receptor function and response of semiconductor gas sensor are described, following the illustrations of some relevant key issues such as tunneling transport.
1. The document discusses a computational fluid dynamics (CFD) simulation of chlorine gas dispersion within an urban area near a water treatment facility in Tehran, Iran.
2. The simulation considered different chlorine gas leakage scenarios from pipelines or storage tanks under various conditions to analyze chlorine gas behaviors, dispersion, distribution, accumulation, and potential hazards.
3. The CFD results were used to investigate chlorine gas dispersion and suggest some prevention and post-incident solutions to reduce risks and hazards from possible chlorine gas leaks.
SOME THEORETICAL ASPECTS OF HYDROGEN DIFFUSION IN BCC METALS AT LOW TEMPERATURESijrap
Purpose of the work is to discuss some theoretical aspects of the diffusion of hydrogen atoms in the crystal
lattice of BCC metals at low temperatures using the methods of statistical thermodynamics. The values of
the statistical model calculations of H diffusion coefficients in α-Fe, V, Ta, Nb, K are in good agreement
with the experimental data. The statistical model can also explain deviations from the Arrhenius equation
at temperatures 300-100 K in α-Fe, V, Nb and K. It was suggested that thermally activated fast tunnelling
transition of hydrogen atoms through the potential barrier at a temperature below 300 K provides an
almost free movement of H atoms in the α-Fe and V lattice at these temperatures. The results show that
quantum-statistical effects play a decisive role in the H diffusion in BCC metals at low temperatures. Using
the statistical model allows for the prediction of the diffusion coefficient for H in BCC metals at low
temperatures, where it’s necessary to consider quantum effects.
This document discusses a study investigating the shear viscosity and diffusion coefficients of liquid transition metal alloys NixCo1-x, CoxFe1-x and NixFe1-x using the distribution function method. The interionic interactions are described using a local pseudopotential model that accounts for d-band effects. Pair correlation functions are derived from Percus-Yevick theory for hard spheres, with effective diameters determined by the LWCA theory. Results for shear viscosity agree well with available experimental data over the entire concentration range.
This document discusses estimation of flotation rate constants and particle-bubble interactions considering key hydrodynamic parameters. It summarizes two stages of the study:
1) Prediction and evaluation of particle-bubble sub-processes using analytical and numerical models, finding numerical models predict higher collection efficiencies due to modeling assumptions.
2) Using response surface modeling to determine the relative intensity and interrelations of key factors (particle size, density, bubble size, velocity, turbulence) on particle-bubble encounter efficiency and flotation rate constant, finding particle size most affects encounter efficiency while bubble velocity most affects rate constant.
The study aims to overcome limitations in modeling particle-bubble interactions and kinetics, and provides new insights into inconsist
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
The document describes a time-dependent two-dimensional mathematical model of air pollution from an area source. The model considers primary pollutants emitted and converted into secondary pollutants for an urban area. It takes into account variable wind velocity and eddy diffusivity profiles. Secondary pollutants are formed through first-order chemical conversion of primary pollutants. This results in a coupled system of partial differential equations for primary and secondary pollutants. The system is solved using the Crank-Nicolson implicit finite difference technique. The effects of time-dependent emissions and various meteorological parameters on pollutant dispersion and concentration contours are analyzed.
Magnetic chitosan nanoparticles for removal of cr(vi) from aqueous solutionhbrothers
This document describes research on using magnetic chitosan nanoparticles for removing Cr(VI) from aqueous solutions. The researchers introduced a simple method to prepare magnetic chitosan nanoparticles via co-precipitation and epichlorohydrin cross-linking. Characterization showed the nanoparticles were spherical and around 30 nm in size. Adsorption experiments found Cr(VI) removal was highly dependent on pH, with maximum adsorption of 55.80 mg/g occurring at pH 3. Kinetic data fit a pseudo-second order model and isotherm data fit the Langmuir model well. The magnetic chitosan nanoparticles showed potential for use in wastewater treatment applications to remove Cr(VI).
The effect of disturbance factor on the stability of tunnels (Case study: Tun...IJRES Journal
Disturbance factor (D) is related to excavation method and cause damage and stress relief in the rock masses. The convergence and plastic zone around tunnels depends on the disturbance factor of rocks.This study has been in the tunnel No.2 of Kurdistan in NW of Iran which is composed of shale rocks. In tunnel modeling, different disturbance factors(0 to 1) areanalyzed using phase2 software and the amount of displacement and extent of plastic zone in around the tunnelis determined. The obtain results show that by increasing of disturbance factor, the displacement and plastic zone around the tunnel has increased and the most increase has occurred in disturbance factors 0.8 to 1. Therefore, for excavation of this tunnel, the blasting method should not be used and instead of it, the mechanical methods must be used.
Effect of Rotation on a Layer of Micro-Polar Ferromagnetic Dusty Fluid Heated...IJERA Editor
This paper deals with the theoretical investigation of effect of rotation on micro-polar ferromagnetic dusty fluid
layer heated from below in a porous medium. Linear stability analysis and normal mode analysis methods are
used to find an exact solution for a flat micro-polar ferromagnetic fluid layer contained between two free
boundaries . In case of stationary convection, the effect of various parameters like medium permeability
parameter, non-buoyancy magnetization parameter, micro-polar coupling parameter, spin-diffusion parameter,
micro-polar heat conduction parameter, dust particles parameter and rotation parameter has been analyzed and
results are depicted graphically. In the absence of dust particles, rotation, micro-viscous effect and micro-inertia,
the sufficient condition is obtained for non-oscillatory modes
A full experimental and numerical modelling of the practicability of thin foa...Mehran Naghizadeh
This paper presents the performance of geofoam-filled trenches in mitigating of ground vibration transmissions by the means of a full experimental study. The results are interpreted in the frequency domain. Fully automated 2D and 3D numerical models are applied to evaluate the screening effectiveness of geofoam-filled trenches in the active and passive schemes. Experimental results are in good agreement with the prediction of numerical modelling. The validated model is used to investigate the influence of geometrical and dimensional features on the trench. In addition, three different systems including single, double and triangle wall obstacles are selected for analysis, and the results are compared for various situations. The parametric study is based on complete automation of the model through coupling finite element analysis software (Plaxis) and Python programming language to control input, change the parameters, as well as to produce output and calculate the efficiency of the barrier. The results show that the depth and the width of approximately 1λr and 0.2λr, respectively are enough to reach the acceptable amount of efficiency for the active isolation for all three systems. For the passive scheme, the role of depth can be ignored for the single and double wall barriers, while depth plays a significant role for the triangle wall system.
Time Evolution of Density Parameters for Matter and Dark Energy and their Int...IJASRD Journal
In the framework of Brans-Dicke (BD) theory, the first part of the present study determines the time dependence of BD parameter, energy density and Equation of State (EoS) parameter of the cosmic fluid in a universe expanding with acceleration, preceded by a phase of deceleration. For this purpose, a scale factor has been so chosen that the deceleration parameter, obtained from it, shows a signature flip with time. Considering the dark energy to be responsible for the entire pressure, the time evolution of energy parameters for matter and dark energy and the EoS parameter for dark energy have been determined. A model for an effective interaction term, between matter and dark energy, has been proposed and calculated. Its negative value at the present time indicates conversion of matter into dark energy. Using this term, the time dependence of the rates of change of matter and dark energy has been determined. It is found that the nature of dependence of the scalar field upon the scale factor plays a very important role in governing the time evolution of the cosmological quantities studied here. The present study provides us with a simple way to determine the time evolution of dark energy for a homogeneous and isotropic universe of zero spatial curvature, without involving any self-interaction potential or cosmological constant in the formulation.
The International Journal of Engineering and Science (The IJES)theijes
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability
This document presents a new method for detecting corrosion in pipelines based on measuring natural frequencies. The method uses Rayleigh's Law to relate changes in natural frequency to the location and degree of corrosion damage. Finite element models are used to validate the method. The models show that measuring the first and second natural frequencies can accurately determine both where corrosion is located and how severe it is, as indicated by the reduction in bending stiffness. The accuracy depends on having a reasonable estimate of the length of the corroded region. This new natural frequency method provides a simple way to detect pipeline corrosion compared to existing techniques.
comparision between reinforced concrete usingravi529204
This document presents a study on using ultrasonic guided waves to monitor corrosion in fiber reinforced concrete. The study simulates corrosion through notches and delamination in steel bars embedded in concrete specimens. Ultrasonic pulse echo and transmission techniques are used to monitor the bars. For bars undergoing actual accelerated corrosion, monitoring detects signal attenuation and disappearance, unlike simulated corrosion monitoring. The ultrasonic methodology can successfully monitor real corrosion in reinforced concrete beams by identifying the corrosion mechanism and location and extent of damage.
Similar to Analysis of Heavy Metal Pollution Based on Two-Dimensional Diffusion Model (20)
Scientific Management of Equipment in Medical Innovation LaboratoryScientific Review SR
Aim; To solve the problem of innovation laboratory instrument management and improve laboratory management level. Method; It is necessary to do an excellent job in managing innovative laboratory equipment by improving the equipment management system, functional division management, appointment registration, and strengthening the construction of management teams to guarantee the cultivation of innovation and entrepreneurship capabilities of undergraduates. Results; The number of innovative experimental projects approved and the number of project groups that the laboratory can accept at the same time was increased significantly. The utilization rate of laboratory equipment has increased, and the vacancy rate has decreased. Conclusion; Excellent instrument management can significantly improve the efficiency of scientific research in the innovation laboratory.
Internationalization and Sustainable Operations: A Broad Investigation of Chi...Scientific Review SR
We investigate if internationalization behaviors encourage sustainable operations of China’s manufacturing firms due to their substantial impact on climate change and special governance modes, and organize a heterogeneity test to clarify what kind of internationalization behaviors can robustly influence such operations. We find that firms with abundant assets and heavy-polluting feature are more committed to sustainable operations. Getting close to international sustainability standards, international auditing standards, and international business all improve sustainable operations. Heterogeneity test further shows that compared with international standards, the positive impact of international business on sustainable operation lacks a robustness, which responds to an argument that for one country, international business acts as a double-edged sword. Overall, this paper reveals internationalization as a key indicator significantly influencing economic, ecological, and social spheres in manufacturing sectors of emerging markets, and complying with well-accepted international standards can be significantly embodied in a more optimistic sustainable operations. However, how to deal with international business in a right manner is a research highlight worthy of ongoing discussion. We focus on different types of internationalization behaviors, and this indicator can theoretically inspire future study to dialectically evaluate the role of internationalization in addressing sustainability problems in emerging markets’ pillar industries.
Mechanical Engineering in Ancient Egypt, Part 92: Tomb Inscription During the...Scientific Review SR
This document discusses ancient Egyptian tomb inscriptions from the Old Kingdom period, specifically the Third through Fifth Dynasties. It provides several examples of reliefs and scenes from tombs that contain hieroglyphic inscriptions, including a relief of a dentist from the Third Dynasty, a hunting scene from a Fourth Dynasty tomb with an inscription above, and a colorful scene from a Fifth Dynasty tomb with a descriptive text in four columns above the images. The document examines the development of tomb inscriptions during this early period in ancient Egypt and highlights the important role they played in documenting the tomb owners' lives and achievements.
Usability Engineering, Human Computer Interaction and Allied Sciences: With R...Scientific Review SR
Human Computer Interaction is actually responsible for the designing of the computing technologies keeping in mind the aspects of Interaction. Some of the fields viz. Man-Machine Interaction (MMI), User Experience Designing, User Experience Design, Human Centered Designing etc and importantly all these systems and technologies are dedicated to the designing of interface of various tools and systems such as computers, laptops, electronic systems, smart phones etc. Information Technology field is growing rapidly and there are various technologies are increasing viz. Big Data Management, Cloud Computing, Green Computing, Data Science, Internet of Things (IoT), HCI, Usability Engineering etc. Usability Engineering is gaining as a field of study as well and dedicated in creation of the higher usability and user friendliness of the electronic tools and products. In this field few aspects and technologies are most important and emerging viz. Human cognition, behavioral Research Methods, Quantitative techniques etc for the development of usability systems. Designing, implementation, usability even in multimedia material viz. audio-video may also practice in the Usability Engineering and allied fields. Wireframes including few other prototypes are required in maintaining of the better and healthy man and machine interaction. As the field is growing therefore, it is applicable in other sectors and allied areas and among these agriculture is important one. In agricultural sector different applications of information technologies are increasing and among this Usability Engineering and HCI are important one. In pre production and also in post production; directly and indirectly this technology is emerging and growing. This paper talks about the basics of this technologies and also its current and future technologies with reference to academic potentialities of this branch in Agricultural Informatics programs.
Concentration Distribution and Ecological Risk Assessment of Polycyclic Aroma...Scientific Review SR
The ecological risk assessment of 16 USEPA priority polycyclic aromatic hydrocarbon (PAHs) in water and sediments of Kolo creek, Niger Delta Nigeria was assessed the samples were collected from November, 2018 to June, 2019 from seven locations (A-G) along the creek. The samples were extracted using standard methods and analyzed using gas chromatography (model: HP5890 S). The concentrations of the PAHs in the water and sediment samples ranged between 0.000 - 9.239 µ/L and .002 – 374.35µg/Kg respectively. All the compounds analyzed were detected in all the sampling places, even area far from the flow stations. Hence, the urban runoffs, sewage discharges, and agricultural activities are implicated. Four rings hydrocarbon were present in higher concentration when compared to other PAHs in all sampling sites, with benz (a)anthracene having the highest values in both matrixes. Similarly, lower molecular weight (LMW) PAHs were present in lower concentrations in all sampling sites and they are known to exhibit higher lethal toxicity than the larger PAHs. HMW were present in high concentrations than LMW and are persistent in the environment as a result of their increase resistance to oxidation, reduction and vaporization as molecular weight increases. Similarly, The PAFs of the investigated creek is less than 5%, suggesting existences of minor ecological risks that are insignificance. However, the TEQs detected in high molecular weight showed that there is possibility of cancer to those who may be exposed to the bottom sediment. The indices measured in this habitat may put more pressures to the aquatic organisms and cause drastic changes to their ecosystem which may lead to species extinction.
Volume Fractions of Tantalum Carbides Deduced from the Ta Contents in the Mat...Scientific Review SR
Some superalloys for service at high temperature under stresses are strengthened by tantalum carbides. Their creep resistance depends on the quantity of TaC and this is the reason why it is often important to control the volume fraction of these carbides in the microstructure. Metallographic preparation followed by electron imaging and surface fraction measurements by image analysis is a frequent way for that. Another possibility is to deduce the mass fraction of TaC, and after their volume fraction, from the chemical composition of the matrix when the alloys are only double–phased, on the {matrix + TaC} type. In this work three alloys – chemically designed to be made exclusively of matrix and TaC – were elaborated and isothermally exposed to an elevated temperature for a duration long enough to allow the alloys being at their thermodynamic equilibria. The chemical compositions of the alloy and of its matrix were measured and the results allowed evaluating their TaC mass fractions which were converted in volume fractions. The obtained TaC fractions were compared to results issued from thermodynamic calculations. Good agreement was found for the three alloys, and this allowed to exploit the used software and thermodynamic database to explore further the microstructures at the same high temperature, notably to know the conditions on the Co, Ni, Cr, Ta and C contents to keep the {matrix + TaC} structure and to avoid any possible partial melting.
Assessment of the Coliform Bacterial Load of Some Drinking Water Sources in D...Scientific Review SR
Drinking water samples from 5 sachet water companies, 3 boreholes and 2 taps, collected from different locations of Dutse Metropolis of Jigawa State, Nigeria were analysed for coliform bacterial counts using the Membrane Filtration Technique. All the samples contained some amounts of total coliforms, but mostly within permissible levels. Thirty three percent (33%) of the samples from borehole, 60% from sachet water and 100% from the taps contained faecal coliforms, which indicates contamination. Cultures of the faecal coliforms obtained were morphologically identified using the gram-staining procedure and some series of biochemical tests were carried out in order to identify the organisms. The identified organisms were Escherichia coli (E. coli), Klebsiella sp. and Citrobacter sp. Presence of coliforms above the regulatory set standards indicates contamination and un-safeness of the water for drinking. Presence of organisms such as E. coli, Klebsiella sp. and Citrobacter sp. necessitates improvement in monitoring and water hygiene practices to improve the quality of drinking water in the study area.
Bio Inspired Self-Curing Composite: A Leap into Augmented EnactmentScientific Review SR
Relentless progress has been made on composite materials, their manufacturing processes and their structural design in past few decades. Nevertheless, the approval of composite materials in all engineering disciplines is constrained due to its susceptibility to various kinds of defects during manufacturing stage viz porosity, foreign body inclusion, incorrect fiber volume, bonding defect, fiber misalignment, ply misalignment, incorrect curing cycle, wavy fiber, ply cracking, delamination, fiber microstructural defects etc. Hence there was a requirement of techniques to somehow overcome these defects during the service life of composites being used in various structures and equipment. This promising field of research has made great progress over the past several years, but many procedural encounters are still to be overcome, and there exists a great need for focused research to address several areas of concern. On the other hand, nature has materials that have curing potential and repair strategies ensuring their survival. Sustained development in the field will produce new curing chemistries that possess greater stability, faster kinetics. Tailor-made placement of curing agents is dynamic research subject at the cutting edge of self-curing. New bio-imitative curing agents are closely connected to vascular networks. The purpose of this technical paper is to sort the methodology in line with ongoing research efforts in composites. A perspective on current and future self-curing approaches using this biomimetic technique is offered.
Influence of Information and Communication Technology (ICT) in Tourism Sector...Scientific Review SR
Nepal is a country blessed with natural beauty, diverse culture, majestic Himalayas, religious destination which attracts thousands of tourists every year making the tourism industry progressive to flourish. Information Communication Technology (ICT) proves to be an effective tool for strengthening the tourism industry. Thus, the purpose of this research study is to analyze about the past scenario of tourism industry, advent of ICT in tourism industry, positive impacts of ICT in tourism industry through in-depth interview with tourism experts and people who have worked for tourism since decades. This study is a form of qualitative research where narrative inquiry has been selected and the scenario has been analyzed through themes developed from the narratives. The result reveals that the emerging technology brings positive impacts to tourism industry assisting branding, promotion of the country, enhancing networks through communication and easily booking tours. The proper utilization of ICT helps to welcome tourists and to give identity of our country Nepal to the world.
Reinforcement of Bakelite Moulding Powder in Acrylonitrile Butadiene Rubber (...Scientific Review SR
The document discusses a study that compares the effects of adding two different phenolic resins - cashew nut oil modified phenol-formaldehyde resin (CN-m-PF) and Bakelite moulding powder (BMP) - to carbon black filled acrylonitrile butadiene rubber (NBR). The addition of both resins increases hardness and modulus but decreases some mechanical properties like tensile strength and elongation at break. CN-m-PF provides better processability and mechanical properties than BMP at the same content. However, BMP can also enhance stiffness without processing issues and may be preferred due to its lower cost. The document reports results of various tests measuring properties like curing characteristics, hardness, tensile strength,
Toxic Effect of Glyphosate-Pesticide on Lipid Peroxidation Superoxide Dismuta...Scientific Review SR
The oxidative stress indices lipid peroxidation (LPO), superoxide dismutase (SOD) and catalase (CAT) in juvenile Clarias gariepinus (average weight 200.15 g) exposed to sub - lethal dose 2.40mg/L and 4.98mg/L of glyphosate was investigated over a period of days 1,5,10 and 15 in three replicates. The colorimetric analysis showed increase in lipid peroxidation from 4.55 ±2.14a1 to 12.12± 10.00a1at 2.40mg/L but remain the same at 4.98mg/L (4.55±2.14a1) compared with control (3.03±0.01a1 to 1.51±2.14b1) from day 1 to 15. The SOD activity decreased significantly with time and concentration compared with control. The Catalase activity at day 15 decreased to 0.17±0.05a1 in 2.40mg/L but further increased to 0.28±0.05b1 in 4.98mg/L compared to 0.28±0.02a1 catalase activity as control. The result suggests that glyphosate induce oxidative stress that may overwhelm the antioxidant system in juvenile catfish especially at higher concentrations with long exposure.
Wheeled robots are often utilized for various remote sensing and telerobotic applications because of their ability to navigate through dynamic environments, mostly under the partial control of a human operator. To make these robots capable to traverse through terrains of rough and uneven topography, their driving mechanisms and controllers must be very efficient at producing and controlling large mechanical power with great precision in real-time, however small the robot may be. This paper discusses an approach for designing a quad-wheeled robot, which is wirelessly controlled with a personal computer (PC) by medium-range radio frequency (RF) transceiver, to navigate through unpaved paths with little or no difficulty. An efficient servo-controlled Ackerman steering mechanism and a high-torque driving power-train were developed. The robot’s controller is programmed to receive and respond to RF control signals from the PC to perform the desired motions. The dynamics of the robot’s drivetrain is modeled and analyzed on MATLAB to predict its performances. The robot was tested on various topographies to determine its physical capabilities. Results show that the robot is capable of non-holonomically constrained motions on rough and uneven terrains.
Geometrical Analysis and Design of Tension-Actuated Ackermann Steering System...Scientific Review SR
The tension-actuated steering system is a vehicular steering design that comprises a motorized gear system, pulleys, inelastic string, main steering bar, and a strain gauge. This development is aimed to produce a steering design that could enhance the efficiency of steering systems in quad-wheeled (i.e. four-wheeled) robots. In this work, the steering system of conventional passenger vehicles and existing quad-wheeled robots are reviewed and their technical deficiencies are improved based on cost, power and production factors. Thus, the tension-actuated steering system is proposed as a solution for mechanizing steering functions in quad-wheeled robots. It is expected that this work will stimulate interest and enthusiasm.
A Study of Propensity Score on Influencing Factors of Length of Stay in Hospi...Scientific Review SR
Background: Burns are a global public health problem, which are universal and can happen to anyone. Because the physical functions in children and adults are different, the confounding factors are easy to affect the results of study. Objective: In this study, we aimed to explore influencing factors of the length of hospital stay (LOS) when the confounding factors were excluded by Propensity Score (PS) in children and adults. Methods: Patients hospitalized for burn from 2014 to 2016 were retrieved from the medical record system of a general biggest hospital in Zunyi. A database was established to analyze the influencing factors of LOS between children and adults by the PS. Results A total of 465 children (61.7% males) and 327 (69.7% males) adults were recruited. The average age was 3.61±3.57 years and 42.48±14.76 years in children and adults with burns respectively. Before PS matching, low age and skin grafting were the protective factors for LOS (Hazard Ratio [HR]=0.993 and 0.339). The risk factors of LOS were male (HR=1.234), the burn depth and total body surface area (TBSA), and burn etiology (HR=1.497). After PS matching, only skin grafting (HR=0.080) and treatment within 24 hours (HR=1.865) were the common influencing factors of LOS. Conclusion the confounding factors were excluded by the PS method, and skin grafting was still a protective factor of LOS for both children and adults. The results provide a reference for the promotion of skin grafting to reduce LOS in burn patients.
Concrete is one of the reliable, durable, economical and acceptable construction materials among the building and construction stakeholders worldwide. Performance of concrete could be threatened especially reinforced concrete by some processes such as corrosion, sulfate attack among others. Corrosion of reinforcement in reinforced concrete can be induced by carbonation process. Even though carbonation initiates corrosion, it has been gathered that carbonation could still be of immense benefits to building and construction industries if its mechanism of operation is understudied. This research work has therefore investigated the effect of carbonation on some selected mechanical properties of concrete such as compressive strength, flexural strength, water absorption and weight changes. Concrete cubes and beams of M15 grade with 0.5 % water-cement ratio were prepared and subjected to accelerated carbonation. Their compressive strength, flexural strength, water absorption and weight changes were determined in accordance with the relevant standards. The outcomes show that carbonation improves all the mechanical properties investigated. The use of carbonation can be positively explored in reinforced concrete provided there is adequate nominal cover.
Biogas Synthesis as Means of Solid Waste Management in Kampala, UgandaScientific Review SR
Cattle dung, cooked food waste, and chicken droppings mixed with coffee husks have been used separately and also as mixtures to form anaerobic digestion slurries in a bid to treat to degrade the organic fractions of these wastes and recycle the bio-fertilizer after recovering biogas. Single and mixed substrate slurries evolved significant quantities of methane within 27days together with reduced mass of soil conditioner. The volume of biogas formed in cogeneration mixtures were higher than for single substrate digestion due to the C/N ratio shifting to near 30:1 as a result of mixing. So degradation of organic pollutants was higher in mixed substrate digestion mixtures. Our study yielded average volumes ranging from 315 to 435+ 5.65.mL/L which was in agreement with what is in literature. Digestion of cattle dung, cooked waste foods, and droppings of chicken and mixed substrate slurries using sludge inoculums was very effective in degrading solid waste from homes, thus detoxifying it to bio-fertilizers. Although both single and mixed substrate digestion of waste yielded high enough volumes of biogas; digestion of slurry of mixed organic solid waste substrates is better method of waste management. Digestion of garbage from Kampala should be tested at macro levels at both ambient and mesophilic temperatures. There is need to try out the garbage digestion experiments in the semi-arid towns as well as very cold towns in Uganda.
The Influence of Partial Replacement of Some Selected Pozzolans on the Drying...Scientific Review SR
Concrete is prone to cracking and one of the major causes of cracking is drying shrinkage of the hardened concrete. This research work was carried out to study the influence of partial replacement of some selected pozzolans on the drying shrinkage of concrete. Four pozzolans used in this study, were made to replace cement at various percentages resulting in various concrete mixes. Setting time test was conducted for the various cement mixes using Vicat’s apparatus and drying shrinkage test was done for the concrete test specimens. The results of the setting time indicate that partial replacement of pozzolans with ordinary Portland cement increases both the initial and final setting time of cement as the percentage replacement increases. Similarly, drying shrinkage results show that concrete made with Groundnut Shell Ash (GSA) and Locust Bean Pod Ash (LBA) at 12% replacement will have a stable and better shrinkage resistance than the control at both 56 days and 90 days. Meanwhile, the control concrete gives a better drying shrinkage at 28 days curing. In conclusion, the results show that pozzolanas [Bamboo Leaves Ash (BLA), Locust Bean Pod Ash (LBA), Sugarcane Bagasse Ash (SBA) and Groundnut Shell Ash (GSA)] can successfully replace cement up to 12% without necessarily affecting the shrinkage ability of the produced concrete. It also shows that Groundnut Shell Ash (GSA), Locust Bean Pod Ash (LBA) and Bamboo Leaves Ash (BLA) are more resistance to drying shrinkage than the control.
Study on the Granulation of FLY Ash from Thermal Power StationScientific Review SR
This study examined the granulation of fly ash from a thermal power station in Bulgaria to utilize this waste material. The highest yield of granules was achieved using clayish slip as a binder. Adding sodium phosphate as a reinforcing additive increased the granule yield and strength. Sintering the granules increased their density, decreased porosity, and substantially improved their compression strength up to 2.2 MPa, making them suitable for use as a filler in light concretes. The granulation process and additions showed potential for utilizing fly ash waste from thermal power stations.
Machining Versus Molding Tolerances in Manufacturing Automotive Sealing SystemsScientific Review SR
The automotive industry has been at the forefront of converting traditional metal parts to plastics. The latter surely offer greater design freedom, opportunity for consolidation, fewer assembly operations, reduced secondary finishing, weight reduction, lower total system costs, a range of properties tailored to specific applications, the ability to withstand temperatures, immunity to most chemicals and corrosive environments. They offer processing in many colors, electrical non-conductivity (insulation from electrical shocks), good thermal breaks (“warmth-to-the-touch”), and low sound transmission (tendency to muffle noise). Nonetheless, plastics have only tapped an estimated 15% of their tremendous potential to replace metals. This is particularly to increase with newer high-performance plastics, increasing sophistication in alloying and blending technologies, and use of computer-aided design and engineering (CAD/CAE) systems. The latter enable engineers to visualize complex parts and molding tools more effectively and faster than ever before. This article identifies fundamental steps and requirements to conduct an efficient and successful conversion of metallic parts to plastics, reviewing the replacement design process from concept to production; an under-the-hood rear retainer for Ford Motor Company is detailed as a case study.
Sinthesis and Properties of Marble-Like Glass-Ceramics Using of Ash from Ther...Scientific Review SR
Color marble-like glass-ceramic materials were obtained through thermal treatment of glasses of the system CaO-Al2O3-SiO2 by using natural materials with the introduction of waste materials - ash from thermal power plants (TPP). The melting of the glass batch was in corundum crucibles at 1450oC with an isothermal hold of 60 min. The glasses obtained was fritted in distilled water and dried for 6 hours at 100oC, then completely crushed and divided into fractions with grain size of 0.8 mm, 1.0 mm, 2 mm, 2.5 mm and over 2.5 mm. It was found that the use of ash from TPP lead to higher values of degree of transformation (crystallization) than using base composition. Values of Avramy parameter’s in the range n=1,0 ÷ 1,6 are showed that crystallization of the glass frit is largely heterogeneous and crystal growing starts from the surface. The introduction of ash from TPP to native glasses carry out to significant reduction of energy of crystallization by Ес=289 kJ/mol to Ec=221 kJ/mol. The glass-ceramic materials were obtained through a one stage crystallization - 1050÷1070оС and an isothermal hold of 60 min., colored white, yellow brown to dark brown. The main crystalline phase in glass-ceramics is β-vollastonite with needle habit, size of crystals - ĺ = 40 ÷ 120 μm and d <5 μm in quantities 37 ÷ 42%. As secondary phases depending on the amount of ash have been identified - the anorthite, gehlenite and α-quartz with prismatic habit were appeared. The obtained glass-ceramic materials have a marble-like effect and technical parameters compared with natural granite and marble and have higher values of density, micro hardness, speed grinding, bending strength and chemical resistance. That’s why they can be used in construction such as lining materials.
Test bank calculating drug dosages a patient safe approach to nursing and mat...rightmanforbloodline
Test bank calculating drug dosages a patient safe approach to nursing and math 2nd edition by castillo werner mccullough
Test bank calculating drug dosages a patient safe approach to nursing and math 2nd edition by castillo werner mccullough
Test bank calculating drug dosages a patient safe approach to nursing and math 2nd edition by castillo werner mccullough
Emotional and Behavioural Problems in Children - Counselling and Family Thera...PsychoTech Services
A proprietary approach developed by bringing together the best of learning theories from Psychology, design principles from the world of visualization, and pedagogical methods from over a decade of training experience, that enables you to: Learn better, faster!
Solution manual for managerial accounting 18th edition by ray garrison eric n...rightmanforbloodline
Solution manual for managerial accounting 18th edition by ray garrison eric noreen and peter brewer_compressed
Solution manual for managerial accounting 18th edition by ray garrison eric noreen and peter brewer_compressed
Simple Steps to Make Her Choose You Every DayLucas Smith
Simple Steps to Make Her Choose You Every Day" and unlock the secrets to building a strong, lasting relationship. This comprehensive guide takes you on a journey to self-improvement, enhancing your communication and emotional skills, ensuring that your partner chooses you without hesitation. Forget about complications and start applying easy, straightforward steps that make her see you as the ideal person she can't live without. Gain the key to her heart and enjoy a relationship filled with love and mutual respect. This isn't just a book; it's an investment in your happiness and the happiness of your partner
About CentiUP - Introduction and Products.pdfCentiUP
A heightened child formula, with the trio of Nano Calcium, HMO, and DHA mixed in the golden ratio, combined with NANO technology to help nourish the body deeply and comprehensively, helps children increase height, boost brain power, and improve the immune system and overall well-being.
Cyclothymia Test: Diagnosing, Symptoms, Treatment, and Impact | The Lifescien...The Lifesciences Magazine
The cyclothymia test is a pivotal tool in the diagnostic process. It helps clinicians assess the presence and severity of symptoms associated with cyclothymia.
Digital Health in India_Health Informatics Trained Manpower _DrDevTaneja_15.0...DrDevTaneja1
Digital India will need a big trained army of Health Informatics educated & trained manpower in India.
Presently, generalist IT manpower does most of the work in the healthcare industry in India. Academic Health Informatics education is not readily available at school & health university level or IT education institutions in India.
We look into the evolution of health informatics and its applications in the healthcare industry.
HIMMS TIGER resources are available to assist Health Informatics education.
Indian Health universities, IT Education institutions, and the healthcare industry must proactively collaborate to start health informatics courses on a big scale. An advocacy push from various stakeholders is also needed for this goal.
Health informatics has huge employment potential and provides a big business opportunity for the healthcare industry. A big pool of trained health informatics manpower can lead to product & service innovations on a global scale in India.
2024 Media Preferences of Older Adults: Consumer Survey and Marketing Implica...Media Logic
When it comes to creating marketing strategies that target older adults, it is crucial to have insight into their media habits and preferences. Understanding how older adults consume and use media is key to creating acquisition and retention strategies. We recently conducted our seventh annual survey to gain insight into the media preferences of older adults in 2024. Here are the survey responses and marketing implications that stood out to us.
Analysis of Heavy Metal Pollution Based on Two-Dimensional Diffusion Model
1. Scientific Review
ISSN(e): 2412-2599, ISSN(p): 2413-8835
Vol. 5, Issue. 4, pp: 87-92, 2019
URL: https://arpgweb.com/journal/journal/10
DOI: https://doi.org/10.32861/sr.54.87.92
Academic Research Publishing
Group
*Corresponding Author
87
Original Research Open Access
Analysis of Heavy Metal Pollution Based on Two-Dimensional Diffusion Model
Yunhui Zeng
College of Intelligent Science and Engineering, Jinan University, No. 206, Qianshan Road, Xiangzhou District, Zhuhai City, Guangdong
Province, China
Wenhao Li
College of Intelligent Science and Engineering, Jinan University, No. 206, Qianshan Road, Xiangzhou District, Zhuhai City, Guangdong
Province, China
Hongfei Guo*
College of Internet of Things and Logistics Engineering, Jinan University, No. 206, Qianshan Road, Xiangzhou District, Zhuhai City,
Guangdong Province, China
Yilin Chen
College of Intelligent Science and Engineering, Jinan University, No. 206, Qianshan Road, Xiangzhou District, Zhuhai City, Guangdong
Province, China
Xiaoqing Jiang
School of translation studies, Jinan University, No. 206, Qianshan Road, Xiangzhou District, Zhuhai City, Guangdong Province, China
Bingjie Yu
College of Intelligent Science and Engineering, Jinan University, No. 206, Qianshan Road, Xiangzhou District, Zhuhai City, Guangdong
Province, China
Abstract
This paper takes the propagation characteristics of heavy metals and the judgment of the location of pollution
sources as the research objects, aiming to analyze the propagation characteristics of different heavy metals. Firstly,
the Gaussian diffusion model is conducted to establish the propagation characteristics model of heavy metal
pollutants in the atmosphere. Then, based on the law of conservation of mass and the law of two-dimensional
diffusion, the two-dimensional diffusion model is adopted to establish the propagation characteristics model of
heavy metals in soil moisture. According to these two models, the nonlinear differential equations are established
respectively, revealing that the characteristics of the two propagation ways are related to space, time, diffusion
coefficients, and other factors. Then, in the light of the propagation characteristics of different heavy metals, the least
square method is applied to reduce the data calculation error and obtain the specific location of the pollution source.
Finally, through establishing the three-dimensional diffusion model of heavy metal diffusion by introducing artificial
control, speed and angle of prevailing wind direction, and other factors, the model is further optimized. The
establishment of this model provides an important theoretical basis and guiding significance for the future study of
heavy metal pollutants.
Keywords: Heavy metal pollution; Gaussian diffusion model; Nonlinear differential; Least square method; Three-dimensional
diffusion model.
CC BY: Creative Commons Attribution License 4.0
1. Introduction
Soil heavy metal pollution refers to the phenomenon of high heavy metal content caused by excessive
deposition of trace metal elements in soil due to human activities. With the rapid development of urban economy and
the continuous increase of urban population, the impact of human activities on urban environmental quality is
increasingly prominent. Due to the hysteresis, concealment and long-term nature of soil heavy metal pollution, the
pollution and ecological problems caused often fail to attract enough attention. The focus of people's attention
gradually moves to verify geological environment anomaly in urban soil as well as how to carry out urban
environmental quality assessment and study the evolution model of urban geological environment under the
influence of human activities by applying massive data obtained from verification [1]. Out of the current heavy metal
pollution researches which mainly focus on analyzing the ways and sources of pollution, there are few researches
target at analyzing the propagation characteristics of heavy metal pollution and determining the specific location of
pollution sources at home and abroad. Therefore, researchers aimed at determining the specific location of pollution
sources are of certain necessity. The equal-standard pollution load method proposed by Zhao Jinjin [2]obtained the
location of pollution sources by simply listing the concentration of different element pollutants at different locations
(Zhao Wei) and making intercomparison, deviating from scientific results. Wang Ying, Jiang Xiaodong and other
people proposed to use the convection-diffusion model in the propagation medium to describe the migration process
of heavy metal pollutants in soil [3] only considering the propagation of heavy metals in a certain direction. Zhang
2. Scientific Review
88
Ganlin and Zhu Yongguan and other people adopted Gaussian diffusion model to study the determination of gas
pollution sources [4], which was not completely applicable to the determination of heavy metal pollution sources in
soil. In general, the analysis of the propagation of heavy metal pollutants in the academic circle generally has the
following problems: The result analysis lacks rigorously scientific calculation; fail to consider the correlation
between heavy metals; the propagation mode of heavy metals is not comprehensive; the method adopted is too
idealized to be practical.
Aiming at the propagation characteristics of heavy metal pollutants and the location of pollution sources, the
Gaussian smoke mass diffusion model is conducted in this paper to establish the propagation characteristics model of
heavy metal pollutants under the action of the atmosphere and the propagation characteristics model under the action
of soil moisture. The propagation mode of heavy metal pollution is probed into more comprehensively, making the
model more practical. Then, based on the law of conservation of mass and the law of two-dimensional diffusion, the
two-dimensional diffusion model is adopted to establish the propagation model of heavy metals in soil moisture, and
nonlinear differential equations are established respectively for the two cases. Finally, through establishing the three-
dimensional diffusion model of heavy metal diffusion by introducing artificial control, speed and angle of prevailing
wind direction, and other factors, the model is further optimized and thus become more comprehensive and
scientific.
2. Measurements
2.1. Data Acquisition and Assumptions
The original data of this paper is from China Society for Industrial and Applied Mathematics, 2011, including
the concentration of eight major heavy metal elements at the sampling point and their background values. For
facilitating analysis and understanding, we make the following assumptions about the model:
(1) The data given in the title is true and authentic;
(2) No degradation of heavy metals;
(3) Assuming the same probability of airflow occurring in all directions, that is, the propagation characteristic of
atmosphere is spherical diffusion;
(4) Ignore the influence of gravity on heavy metal ions.
2.2. Model Establishment and Solution
2.2.1 Model for the Propagation of Heavy Metals in the Atmosphere [5]
The propagation of heavy metals in the air is characterized by spread in all directions. The atmospheric airflow
is constantly changing, which is random. Therefore, it’s assumed that the probability of airflow in all directions is
the same, so the propagation characteristics can be considered as spherical diffusion to make the Gaussian diffusion
model [6] applicable. Thus the pollution resource is recorded as
( )00 0
, ,yx z , the concentration of pollution area as
( ), , ,0C x y z
and the concentration of the heavy metal at any point in the infinite space from the pollution source t as
( ), , ,tC x y z
. The flow rate through the unit normal area within the unit distance is proportional to the concentration
gradient. Therefore,
air
q gradCk= - ×
(1)
airk is the diffusion coefficient of a certain heavy metal in the air,
grad indicates the gradient, and the
symbol indicates that it diffuses from the high concentration to the low concentration. Then the flow through the
time interval
[ ],t t t+ D
is:
1
t t
t
s
qpdsdtM
+ D
= ò òò
(2)
W stands for Inter-space domain, V for the volume of W, N for the surface surrounding of W and
p for
the outer normal vector of N . The increase of heavy metal ions in W is:
( ) ( )2
, , , , , ,
V
C x y z t C x y z t t dvM é ù= - + Dë ûòòò
(3)
According to the law of conservation of mass:
2 1M M=
(4)
And the Gauss formula of the surface area:
S V
qpds div qdv=òò òòò
(5)
div is the divergence mark. Based on the above formula, the integral mean value theorem is conducted to be:
3. Scientific Review
89
( )
2 2 2
2 2 2air air
C C CC
div gradC
t k k
x y z
æ ö÷ç¶ ÷ç ÷ç= = + + ÷ç ÷¶ ç ÷÷çè ø
¶ ¶ ¶
¶ ¶ ¶ , 0t > , , ,x y z- ¥ £ < ¥ (6)
The heavy metal diffusion is regarded as the instantaneous and equal release of heavy metal pollutants to all
directions from a certain pollution source. The initial condition is the point source function acting on the pollution
source coordinates, which can be recorded as:
( ) ( )0 00 00 0
, , , ,y My yx xz zs=
(7)
M represents the total amount of heavy metal release, the initial concentration of heavy metals at time 0;
( )00 0
, ,yx zs
indicates the point source function of diffusion intensity in each unit. Then the solution is:
( )
( )
( ) ( ) ( )
22 2
4
3 2
00 0
, , ,
4
air
t
x y zyx z
M
C x y z t k
air
e
tkp
+ +
-
- - -
=
(8)
The result illustrates that the isosurface of the diffusion concentration Y of heavy metals in the atmosphere is a
spherical surface at any time t , and the value of the concentration R decreases continuously as the distance Y
increases away from the pollution source.
2.2.2 Metal Leachate Diffusion Model in the Soil
The presence of moisture in the soil will lead to heavy metals diffusion in the form of ions. Heavy metals mainly
diffuse from high concentration to low concentration in the surface layer, which mainly affected by the concentration
of heavy metals. Therefore, a two-dimensional propagation model is established based on the horizontal diffusion,
regardless of the influence of altitude. [7]:
2 2
2 2water
C CC
t k
x y
æ ö÷ç¶ ÷ç ÷ç= + ÷ç ÷ç¶ ÷ç ÷è ø
¶ ¶
¶ ¶ (9)
C stands for the concentration of heavy metals, and waterk for the diffusion coefficient of certain heavy metal
in the soil.
With the pollution source coordinate
( )0 0
, yx , the initial concentration M , and solution of the partial
differential equation in the two-dimensional propagation model, the expression of the concentration of heavy metal
pollutants at the moment can be obtained:
( )
( )
( ) ( )
22
4
3 2
0 0
, ,
8
water
t
water
x y yx
M
C x y t ke
t kp
+
-
- -
=
(10)
( )0 0
, yx stands for the pollution source coordinate and M for the initial concentration.
2.2.3 Analysis of Propagation Characteristics
The model analysis of the two propagation characteristics reveals that the farther the heavy metal is from the
pollution source, the lower the concentration is. Therefore, the point with the highest concentration of heavy metals
can be inferred as the source of pollution.
Elements with larger relative molecular mass sink faster and are difficult to move farther through the
atmosphere, thus the heavy metals are divided into groups by their relative molecular masses. The smaller relative
molecular masses of Cu, Ni, As, Zn and Cr are mainly diffused by atmosphere while Pb, Hg and Cd that have larger
relative molecular masses are mainly diffused by soil leachate.
2.2.4 Determination of Pollution Sources
Taking the As element as an example, some points near the highest concentration point of As are selected
to calculate the location of the main pollution source, trying to comply with the assumption of the model. Selection
criteria: measured concentration values: C >5; abscissa:16000< x <20000; ordinate: 8000<
y <20000. Finally, 10
points that meet the requirements are selected. The results are displayed in Table 1:
4. Scientific Review
90
Table-1. Ten points that meet the requirements
C 8.5 10.99 6.35 30.13 6.98 5.41 5.83 6.14 6.69 5.41
x 17087 18738 17814 18134 19767 16301 17904 19007 19072 16289
y 11933 10921 10707 10046 8810 8299 8287 11488 8519 10072
Approximately, the value of z and t of these points is the same. In order to reduce the data error and match
the actual situation, linear regression [8] that based on the principle of least squares method [9] is applied to obtain
the value of
( , )x y , putting a maximum value of C . The result is
( , )x y = (18102, 10066). The main pollution
source locations of the remaining seven elements are worked out by the sam e method, which are showed in Table 2.
Table-2. The main pollution source locations of the eight elements
elements x y concentration
As 18102 10066 30.59
Cd 21449 11386 1621.21
Cu 2383 3692 2528.48
Cr 3299 6018 920.84
Hg 2708 2295 16000
Ni 3305 6022 144.2
Pb 4778 4901 475.33
Zn 13797 9621 3760.82
2.3.1 The Introduction of Three-Dimensional Diffusion Model with Human Governance
The locations of the pollution sources can be affected by natural factors in the actual environment, the paper
adds considerations of human factors into the influence on the original three-dimensional diffusion model [10]. The
intensity of the artificial control can be illustrated as a reduction factor of pollution concentration (but inviting
investment to build factories can be illustrated as an increase coefficient of pollution concentration). The artificial
pollution control can be assumed as a constant G within the range of 0 G 1 , then its three-dimensional
diffusion model that match the actual situation is built:
2 2 2
2 2 2air G
t k
x y z
æ ö÷ç Y Y Y¶Y ÷ç ÷ç= + + - Y÷ç ÷¶ ç ÷÷çè ø
¶ ¶ ¶
¶ ¶ ¶ (11)
0, x , , airt y k
represents the diffusion coefficient of heavy metals in the air, and
G represents the artificial pollution control.
The heavy metal diffusion is regarded as the instantaneous and equal release of heavy metal pollutants to all
directions from a certain pollution source. The initial condition is the point source function acting on the pollution
source coordinate
( )00 0
, ,yx z , which can be recorded as:
( ) ( )0 00 00 0
, , , ,y My yx xz zs=
(12)
M indicates the total amount of heavy metal release, the initial concentration of heavy metals at time 0;
( )00 0
, ,yx zs
is the point source function of diffusion intensity in each unit. The solution of equation (11) that
satisfied equation (12) is:
( )
( )
( ) ( ) ( )
( )
22 2
4
3 2
t00 0
, , ,
4
air
t
G
x y zyx z
M
x y z t k
air
e
tkp
+ +
- -
- - -
Y =
(13)
With the above results, the artificial pollution control G ,and other values such as airk , the concentration of
each metal at a given position is worked out.
The calculation results show that a more effective artificial pollution control will bring a lighter pollution in the
same area and a smaller polluted area for the same pollution source. This is because the artificial pollution control
has a great impact on changing the pollution concentration. The more human governs, the better the effect is, which
is in line with the actual situation.
The above analysis tells that a strong control on the pollution sources and the heavily polluted areas will gain a
more significant effect when conducting heavy metal pollution control and treatment.
5. Scientific Review
91
2.3.2 The Introduction of a Three-Dimensional Diffusion Model with Constant Wind
Direction
Apart from the introduction of the three-dimensional diffusion model of artificial control in the previous section,
the paper also considers the actual influence of the prevailing wind direction on the three-dimensional diffusion
model so that the results obtained by the model are closer to reality. The so-called prevailing wind direction is the
main wind direction of a wind in the city (if the conditions are enough, it can be defined a function of wind direction
over time, converting it into a variable wind direction), and the influence of other wind directions is not considered
here. Extending the previous model, a three-dimensional diffusion model with prevailing wind direction factors is
built:
2 2 2
0 0 02 2 2
cos cos cosair v v v
t x y zk
x y z
a b g
æ ö÷ç Y Y¶Y ¶Y ¶Y ¶Y÷ç ÷ç= + + - - -÷ç ÷¶ ¶ ¶ ¶ç ÷÷çè ø
¶ ¶ ¶
¶ ¶ ¶ (14)
The average velocity of the prevailing wind direction is 0v
, and the angles between the average velocity and the
coordinate axis
, ,x y z are respectively expressed as
, , .
Likewise, the heavy metal diffusion is regarded as the instantaneous and equal release of heavy metal pollutants
to all directions from a certain pollution source. The initial condition is the point source function acting on the
pollution source coordinate
( )00 0
, ,yx z , which can be recorded as:
( ) ( )0 00 00 0
, , , ,y My yx xz zs=
(15)
M represents the total amount of heavy metal release, the initial concentration of heavy metals when time is 0;
( )00 0
, ,yx zs
is the point source function of the diffusion intensity in each unit. Then the solution of the equation
(14) that satisfied the equation (15) is:
( )
( )
( ) ( ) ( )
2 2 2
4
3 2
cos cos cos 00 00 0 0
, , ,
4
air
t
v x v y v zyx z
M
x y z t k
air
e
tk
a b g
p
+ +
-
- - -
Y =
(16)
With the above results, the prevailing wind direction 0v
, the angles
, , between 0v
and the coordinate
axis
, ,x y z , and other values such as airk , the metal concentration at a given position is worked out.
The calculation results reveal that the existence of a certain prevailing wind direction will no longer lead to a
homogeneous spherical diffusion of the heavy metals in the air. Instead, it will propagate in the certain direction of
the wind. In addition, a lager wind speed will be followed by a higher proportion of heavy metals diffusion along the
certain direction of the wind, which is complied with the actual situation, proving the accuracy of the model.
According to the above expansion of the two aspects of the model, human or natural factors such as wind
direction, pollution control, precipitation, river trend, and soil composition may affect the propagation and diffusion
of heavy metals. More detailed data will have a more optimized model.
3. Conclusion
In the paper, the Gaussian diffusion model and the two-dimensional diffusion model are applied to establish the
propagation characteristics model of heavy metals in the atmosphere and soil moisture respectively, making the
model more practical. Linear regression is a follow-up conduction to analyze the Gaussian diffusion model and two-
dimensional diffusion model. The location of the pollution source is scientifically determined by finding the
extremum points and verifying them. Then, considering the prevailing wind direction, artificial control and other
factors, a three-dimensional diffusion model is established and further optimized. The results obtained by the above
models show that the factors affecting the analysis of the pollution source should be taken into consideration when
determining the pollution source of heavy metals, and the pollution propagation mode should be analyzed as
comprehensively as possible. When conducting heavy metal pollution control and treatment, a strong control on the
pollution sources and the heavily polluted areas will gain a more significant effect. This paper is of certain referential
significance for the study of determining heavy metal pollution sources. Through comprehensive consideration of
factors and accurate data collection, the results will be more accurate and can lay a theoretical foundation for the
treatment of heavy metal pollution.
However, due to the limited data obtained, the research in this paper still has some shortcomings, which are
embodied in:
(1) The number of sampling points given in the question is small, which causes a large error after interpolation.
(2) The data provided in the question is sampled in a grid of one kilometer. No specific geographical distribution
is given. Therefore, the analysis of pollution sources is based on interpolation, which is of certain ambiguity.
6. Scientific Review
92
(3) The paper lack of the data, the optimized model is not verified when introducing the model of the influence
factors.
References
[1] Cheng Xiayan and Zhang Yun, 2012. "Journal of chongqing university of science and technology." Natural
Science Edition,
[2] Zhao Jinjin. "Analytical method for heavy metal pollution sources in surface soils." Science & Technology
and Enterprise,
[3] Wang Ying, Jiang Xiaodong, Zhang Lu, and Liu Fei, 2014. "Analysis of heavy metal pollution sources in
urban soil based on CDE." Technology Management Research,
[4] Zhang Ganlin, Zhu Yongguan, and Fu Bojie, 2003. "Evolution of urban soil quality and its eco-
environmental effects." Acta Ecologica Sinica, vol. 23, pp. 539-546.
[5] Chen Ning, Chen Pingping, and Sun Shengli, 2011. "Diffusion model of space smoke cloud." Aerospace
Electronic Warfare, pp. 23-25-49.
[6] Zhuo Jinwu, 2011. MATLAB application in mathematical modeling. Beijing: Beijing University of
Aeronautics and Astronautics Press. pp. 180-181.
[7] Thomas, J., 1976. "A general gaussian diffusion-deposition model for elevated point sources." Journal of
Applied Meteorology,
[8] Bilawal, R., Chongru, L., and Lili, W., 2017. "Least square method- a novel approach to determine
symmetrical components of power system." Journal of Electrical Engineering & Technology, vol. 12, pp.
39-44.
[9] Kevin Diamond, Thomas, F. J., and Michael, P. S., 2003. "Measurement of fluorophore concentrations and
fluorescence quantum yield in tissue-simulating phantoms using three diffusion models of steady-state
spatially." Physics in Medicine & Biology,
[10] Nelson Fumo, M. A. and Rafe, B., 2015. "Regression analysis for prediction of residential energy
consumption." Renewable and Sustainable Energy Reviews, vol. 47, pp. 332-343.