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.
Analysis of Heavy Metal Pollution Based on Two-Dimensional Diffusion ModelScientific Review SR
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 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.
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.
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.
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 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
This summary provides an overview of the document:
1) The document studies the effect of geometrical shape (rectangular vs circular) on hydrodynamic focusing in microfluidic flow cytometry through simulation.
2) The results show that a circular shape maintains a higher concentration at the center of the channel and produces higher fluid velocity compared to a rectangular shape.
3) A circular shape also better sustains the focused stream and peak concentration across the length of the channel compared to the decreasing concentration profile seen in a rectangular channel.
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.
Analysis of Heavy Metal Pollution Based on Two-Dimensional Diffusion ModelScientific Review SR
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 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.
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.
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.
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 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
This summary provides an overview of the document:
1) The document studies the effect of geometrical shape (rectangular vs circular) on hydrodynamic focusing in microfluidic flow cytometry through simulation.
2) The results show that a circular shape maintains a higher concentration at the center of the channel and produces higher fluid velocity compared to a rectangular shape.
3) A circular shape also better sustains the focused stream and peak concentration across the length of the channel compared to the decreasing concentration profile seen in a rectangular channel.
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.
Porous media has two specifications: First its dissipation area is greater than the conventional fins that enhance heat convection. Second the irregular motion of the fluid flow around the individual beads mixes the fluid more effectively. Nanofluids are mixtures of base fluid with a very small amount of nanoparticles having dimensions from 1 to 100 nm, with very high thermal conductivities, so it would be the best convection heat transfer by using porous media and nanofluids. Thus studies need to be conducted involving nanofluids in porous media. For that, the purpose of this article is to summarize the published subjects respect to the enhancement of convective heat transfer using porous media and nanofluids and identifies opportunities for future research.
THE EFFECTS OF UNIFORM TRANSVERSE MAGNETIC FIELD ON LOCAL FLOW AND VELOCITY P...IAEME Publication
A numerical model studied the effects of uniform transverse magnetic field for two fluids (pure water and water with electric conductivity), two different non-magnetizable duct and two flow velocities (steady flow for laminar and incompressible) was examined and The results showed an increase in the magnetic field caused a decrease in the local flow and effected on velocity profile. The result also showed that the water with electrical conductivity more affected than pure water.
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
Dufour and Soret Effects on Convective Heat and Mass Transfer in Non-Darcy Do...IJERA Editor
This paper deals with the MHD convention non-Darcy flow with heat and mass transfer along the vertical surface in a fluid stratified non porous media in the presence of temperature gradients (Soret effects) and concentration gradients (Dufour effects). The differential equations of the governing flow are expand a in terms of perturbation functions as a result we get set of ordinary differential equations of zero,first and second order so the set of equations are solved by using the implicit finite difference scheme. A parametric study of the physical parameters involve in the problem is conducted and a representative set of numerical results are illustrated graphically
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.
Electric potential energy fractal dimension for characterizing permo carbonif...Khalid Al-Khidir
1) The document analyzes fractal dimensions calculated from electric potential energy and capillary pressure measurements on sandstone samples from the Permo-Carboniferous Shajara Formation in order to characterize heterogeneity.
2) Equations relating water saturation, electric potential energy, and fractal dimension were derived and used to calculate electric potential energy fractal dimensions from logarithmic plots.
3) Capillary pressure fractal dimensions were also calculated from logarithmic plots and found to be similar to the electric potential energy fractal dimensions.
4) Fractal dimensions generally increased with increasing permeability and grain size, indicating more interconnected pore spaces in less compacted samples.
Effect of Biot Number on Convective Heat Transfer of Darcy- Forchheimer Nanof...MOHAMMED FAYYADH
This work examined magneto-hydrodynamics flow of aluminum oxide– water based
saturated in porous media that characterized by the Darcy-Forchheimer model. Heat
transfer mechanism was analyzed in the presence of convective heating process and
zero mass flux condition. Tiwari-Das model is employed to study the characteristics of
nanofluid. A uniform magnetic field was imposed and a linear stretching surface was
used to generate the flow. Application of appropriate transformation yields nonlinear
ordinary differential equation through nonlinear Navier-Stokes equations and solved
by Runge–Kutta Fehlberg shooting technique. Importance of influential variables such
as velocity, temperature and concentration were elaborated graphically. Biot number,
porosity, Forchheimer number and nanoparticle volume fraction parameters under
various magnetic field and local Nusselt number were calculated numerically and
interpreted. The results indicate that the effect of magnetic field is dominant on
boundary layer thickness with respect to Biot number, porosity and nanoparticle
volume fraction effect on temperature and nanoparticle concentration profile. An
increase in Biot number, improvement in temperature distribution and nanoparticle concentration. The velocity distribution is decreased when there is an increase in the
Forchheimer number and porosity parameters.
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
Investigating the groundwater of Qorveh-Chaharduli plain in terms of drinking...Innspub Net
Groundwater resources contamination caused by environmental pollutions including both chemical fertilizers and industrial and domestic waste leachate is currently one of the most important environmental issues which has exposed the humans life to risk in some regions. The data of Qorveh plain located in Kurdistan were used in 10-year statistical periods (2002-2012). After selecting the best evaluated resources, considering the data accuracy and distribution, statistics reconstruction and control were conducted and after investigation of Kolmogorov-Smirnov test, it was found that, the data were not normal and consequently, the data logarithm was calculated to be normalized, then, the best variogram model was fitted to spatial structure of the data (SO4, Cl, Na, TDS and TH) using GS+ software. To draw the water zonation map according to Schuler, overlap of the five layers in ArcGIS was used. For the year 2012, most of the eastern parts of the plain (south east and north east) and a small part of the west, totally by an area of 200.2 km2 have poor quality of water for drinking. Get more articles like this at: http://goo.gl/PVkZji
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.
This study aims to investigate the effect of single cavity when it presence at a
specific location within the homogenous soil, on the behavior of seepage and uplift
pressure under a hydraulic structure. The results are analyzed to introduce
deterministic formulae for calculating the amount of seepage and the uplift pressure
head. The work was done in three stages by using experimental investigation; the first
stage includes 36 models of 75mm in diameter cavity, while the second and the third
stages includes eight models for each with 100mm and 34mm diameter of cavity,
respectively. The results shows that, when the cavity presence at the left side its impact
was positive on the seepage behavior. While the influence was changed to a negative
impact when the cavity presence at the right side, except at some specific locations. The
statistical software has been employed to generate the two deterministic formulae, and
the results of multiple regressions are checked by statistical indices for the purpose of
recognizing the reliability of the proposed formulae.
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.
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.
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.
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
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.
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.
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.
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.
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.
Porous media has two specifications: First its dissipation area is greater than the conventional fins that enhance heat convection. Second the irregular motion of the fluid flow around the individual beads mixes the fluid more effectively. Nanofluids are mixtures of base fluid with a very small amount of nanoparticles having dimensions from 1 to 100 nm, with very high thermal conductivities, so it would be the best convection heat transfer by using porous media and nanofluids. Thus studies need to be conducted involving nanofluids in porous media. For that, the purpose of this article is to summarize the published subjects respect to the enhancement of convective heat transfer using porous media and nanofluids and identifies opportunities for future research.
THE EFFECTS OF UNIFORM TRANSVERSE MAGNETIC FIELD ON LOCAL FLOW AND VELOCITY P...IAEME Publication
A numerical model studied the effects of uniform transverse magnetic field for two fluids (pure water and water with electric conductivity), two different non-magnetizable duct and two flow velocities (steady flow for laminar and incompressible) was examined and The results showed an increase in the magnetic field caused a decrease in the local flow and effected on velocity profile. The result also showed that the water with electrical conductivity more affected than pure water.
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
Dufour and Soret Effects on Convective Heat and Mass Transfer in Non-Darcy Do...IJERA Editor
This paper deals with the MHD convention non-Darcy flow with heat and mass transfer along the vertical surface in a fluid stratified non porous media in the presence of temperature gradients (Soret effects) and concentration gradients (Dufour effects). The differential equations of the governing flow are expand a in terms of perturbation functions as a result we get set of ordinary differential equations of zero,first and second order so the set of equations are solved by using the implicit finite difference scheme. A parametric study of the physical parameters involve in the problem is conducted and a representative set of numerical results are illustrated graphically
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.
Electric potential energy fractal dimension for characterizing permo carbonif...Khalid Al-Khidir
1) The document analyzes fractal dimensions calculated from electric potential energy and capillary pressure measurements on sandstone samples from the Permo-Carboniferous Shajara Formation in order to characterize heterogeneity.
2) Equations relating water saturation, electric potential energy, and fractal dimension were derived and used to calculate electric potential energy fractal dimensions from logarithmic plots.
3) Capillary pressure fractal dimensions were also calculated from logarithmic plots and found to be similar to the electric potential energy fractal dimensions.
4) Fractal dimensions generally increased with increasing permeability and grain size, indicating more interconnected pore spaces in less compacted samples.
Effect of Biot Number on Convective Heat Transfer of Darcy- Forchheimer Nanof...MOHAMMED FAYYADH
This work examined magneto-hydrodynamics flow of aluminum oxide– water based
saturated in porous media that characterized by the Darcy-Forchheimer model. Heat
transfer mechanism was analyzed in the presence of convective heating process and
zero mass flux condition. Tiwari-Das model is employed to study the characteristics of
nanofluid. A uniform magnetic field was imposed and a linear stretching surface was
used to generate the flow. Application of appropriate transformation yields nonlinear
ordinary differential equation through nonlinear Navier-Stokes equations and solved
by Runge–Kutta Fehlberg shooting technique. Importance of influential variables such
as velocity, temperature and concentration were elaborated graphically. Biot number,
porosity, Forchheimer number and nanoparticle volume fraction parameters under
various magnetic field and local Nusselt number were calculated numerically and
interpreted. The results indicate that the effect of magnetic field is dominant on
boundary layer thickness with respect to Biot number, porosity and nanoparticle
volume fraction effect on temperature and nanoparticle concentration profile. An
increase in Biot number, improvement in temperature distribution and nanoparticle concentration. The velocity distribution is decreased when there is an increase in the
Forchheimer number and porosity parameters.
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
Investigating the groundwater of Qorveh-Chaharduli plain in terms of drinking...Innspub Net
Groundwater resources contamination caused by environmental pollutions including both chemical fertilizers and industrial and domestic waste leachate is currently one of the most important environmental issues which has exposed the humans life to risk in some regions. The data of Qorveh plain located in Kurdistan were used in 10-year statistical periods (2002-2012). After selecting the best evaluated resources, considering the data accuracy and distribution, statistics reconstruction and control were conducted and after investigation of Kolmogorov-Smirnov test, it was found that, the data were not normal and consequently, the data logarithm was calculated to be normalized, then, the best variogram model was fitted to spatial structure of the data (SO4, Cl, Na, TDS and TH) using GS+ software. To draw the water zonation map according to Schuler, overlap of the five layers in ArcGIS was used. For the year 2012, most of the eastern parts of the plain (south east and north east) and a small part of the west, totally by an area of 200.2 km2 have poor quality of water for drinking. Get more articles like this at: http://goo.gl/PVkZji
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.
This study aims to investigate the effect of single cavity when it presence at a
specific location within the homogenous soil, on the behavior of seepage and uplift
pressure under a hydraulic structure. The results are analyzed to introduce
deterministic formulae for calculating the amount of seepage and the uplift pressure
head. The work was done in three stages by using experimental investigation; the first
stage includes 36 models of 75mm in diameter cavity, while the second and the third
stages includes eight models for each with 100mm and 34mm diameter of cavity,
respectively. The results shows that, when the cavity presence at the left side its impact
was positive on the seepage behavior. While the influence was changed to a negative
impact when the cavity presence at the right side, except at some specific locations. The
statistical software has been employed to generate the two deterministic formulae, and
the results of multiple regressions are checked by statistical indices for the purpose of
recognizing the reliability of the proposed formulae.
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.
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.
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.
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
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.
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.
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.
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.
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.
Air pollution is a global environmental challenge that has continued to receive worldwide attention despite the recent decline in concentration of atmospheric pollutants following stringent environmental protection regulations. The major source of this pollution remains fossil fuels; hence the urgent need for cleaner energy sources. This study presents a review of the models applied in monitoring ambient air quality. The primary aim of air pollution modeling is to identify and quantitatively characterize pollutant emission at its source and subsequent dispersion through the atmosphere, subject to meteorological conditions, physical and chemical transformations. The common models and model assumptions for modeling air pollution and quality were critically reviewed and analyzed in this work for application in both forecasting and estimation of air pollutants on the basis of considered causes and in air quality assessment and air pollution control.
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.
APPLYING FIXED BOX MODEL TO PREDICT THE CONCENTRATIONS OF (PM10) IN A PART OF...IAEME Publication
This document describes applying a fixed box model to predict concentrations of particulate matter (PM10) in part of Al-Kut City, Iraq. The model divides the area into a rectangular box and estimates pollutant concentration based on emission sources, wind speed, and mixing height. Input parameters were calculated based on road, vehicle, construction, and domestic emission inventories. Calculated emission capacities were adjusted based on field surveys. The model was run under two mixing height scenarios and results were similar to portable equipment measurements, indicating the fixed box model is easy to use for evaluating air pollution in Al-Kut City.
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
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.
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.
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).
A Review Article on "Environmental Impact Assessment" (Eia)IRJET Journal
This document provides a literature review of various studies that have assessed the environmental impacts of highway projects using environmental impact assessments (EIAs). It summarizes nine research papers/reports that used EIAs to evaluate the effects of highways on air and water quality, noise levels, and other environmental factors. The studies found that highway construction and use can increase air and water pollution as well as noise levels. However, EIAs help identify these impacts so they can be mitigated. The document emphasizes the importance of thorough EIAs and monitoring both during and after projects to understand environmental effects.
O presente trabalho tem por objetivo utilizar o Método dos Mínimos Quadrados (MMQ) para analisar através do coeficiente de determinação (R2), qual modelo que melhor se ajusta ao comportamento do conjunto de dados da concentração de HCFC-142b em partes por trilhão entre os anos de 1992 a 2018. Ademais, pretende-se fazer estimativas de concentrações futuras entre 5 e 10 períodos em cada um dos modelos de ajuste.
Similar to Analysis of Heavy Metal Pollution Based on Two-Dimensional Diffusion Model (20)
Carbon monoxide (CO) poisoning is a major public health issue in the United States that accounts for approximately 50% of poisoning cases in the nation each year and around 50,000 emergency room visits. In most instances of CO poisoning, the culprit is a malfunctioning or poorly tended heating system within the home or, occasionally, commercial building, which causes the system to leak this hazardous gas. One of the more insidious aspects of CO poisoning is that the gas is odorless and colorless, and victims of CO poisoning often do not realize that there is a problem until they begin to experience the effects of poisoning and have no choice but to seek medical attention. Unfortunately, many victims of CO poisoning die before they are able to seek treatment. This paper makes use of a qualitative, systematic literature review to examine the four major parts of the brain that are most severely affected by CO poisoning. Overall, the literature review showed that the white matter, globus pallidus, basal ganglia, and cortex are the parts of the brain most severely impacted by CO poisoning. While many CO poisoning victims do make it to the hospital on time and are treated, they may nonetheless suffer long-term neurological consequences as a result of their exposure. As such, CO poisoning is a major public health issue.
Drug abuse has now become a major public health problem in Nigeria requiring urgent attention. Although drug abuse cut across all age groups, the youths are however the most affected. This study aimed at assessing Community Pharmacists involvement in the rehabilitation of drug abuse victims. The study was carried out in Abuja Municipal Area Council, questionnaires were administered to Community Pharmacists practicing within the Area Council. A total of 176 Community Pharmacists participated in the study, and slightly above a quarter (27.43%) of them had post-graduate degrees. More than three-quarters (79.5%) of the study participants had received training on drug abuse. A total of 89.2% of the study participants had come across persons suspected to be abusing prescription medicines. Almost all (96.6%) of the study participants indicated that they are willing to advise persons suspected to be abusing drugs on the dangers of drug abuse, and 88.1% of the study participants had spoken to clients concerning abuse of prescription medicines. Also, more than three-quarters (80.1%) of the study participants indicated that pharmacists’ role in the prevention of drug abuse is very important. The study has revealed that Community Pharmacists can play an invaluable role in the rehabilitation of drug abuse victims in Nigeria.
Background; Social Class has shown relation with admissions at Emergency Departments. To assess whether there is a relationship between the level of triage and the social class of patients who attend the emergency department and whether there are other variables that can modulate this association. Methods Observational study with 1000 patients was carried out between May and July 2018 in the Emergency Department of the University Hospital Arnau de Vilanova in Lleida. Sociodemographic variables such as age, gender, country of origin and marital status were analyzed. The triage level and the main explanatory variable was social class. Social class was calculated based on the CSO-SEE 2012 scale. Results 49.4% were male and the average age was 51.7 years. Most of the patients (66.6%) attended the emergency department under their own volition and the most common triage levels were level III or Emergency (45%). There is a significant relationship between age and triage level. The younger patients had a lower triage level (p <0.001). The percentage of patients with lower social class who attended the emergency department for minor reasons was 42% higher compared to the rest of the patients (RR = 1.42; 1.21-1.67 95% CI, p <0.001). Conclusions; Patients with a lower socioeconomic class go to the Emergency Department for less serious pathologies.
This document summarizes a study exploring child healthcare and treatment-seeking behavior in a village located in a haor region of Bangladesh. The study utilized interviews and focus groups to understand the various factors influencing healthcare choices, including the interrelationship between local ecology and health. Key findings were that the haor ecosystem is declining due to overuse of resources, and villagers utilize multiple healthcare sectors - including popular/family-based care, folk healers, and biomedical professionals - with choices influenced by cultural and socioeconomic factors. Government and NGOs could help improve child health by increasing access to services and promoting awareness of nutrition and sanitation practices.
Objective: The purpose of this paper is to review literature on music and biomarkers of stress in order to (1) Identify music interventions and (2) Detail the biomarkers of stress associated with music. Methods: PRISMA guidelines were followed in performing this systematic review. Studies published from January 1995 to January 2020 that pertain to biomarkers of stress and music were identified through the use of the PubMed database, using the keywords: ‘music’ AND ‘biomarker’ OR ‘marker’ OR ‘hormone’. Two authors independently conducted a focused analysis and reached a final consensus on 16 studies that met the specific selection criteria and passed the study quality checks. Results: The reviewed studies were all randomized controlled trials. Reviewed music interventions included Music Listening (ML), Meditational Music (MM), ‘Guided Imagery and Music’ (GIM), and Singing. The studies showed that music is associated with a decreasing trend in cortisol, salivary α-amylase, heart rate, and blood pressure, as well as an increasing trend in Immunoglobulin A (IgA), oxytocin, and EEG theta wave, while testosterone was associated with sex-related differences. Conclusion: Music is associated with significant changes in biomarkers of stress, suggesting that it could be utilized for the development of stress reduction tools.
Background: Nurse practitioners play a vital role in wound care and management because of the prevalence of wounds in the community and hospital setting. Aims and objectives: The purpose was to identify current knowledge and practices of nurses with respect to wound management. Method: A qualitative descriptive research was designed, nineteen nurses in wound care wards in Bingham University teaching hospital were recruited into this study. This was achieved with the aid of a self-administered questionnaire for a two-week period. Results: Three groups of nurses responded to this survey (73.7% males; 31.6% aged 31-40 years). Registered nurses dominated (68.4%), majority of them worked in male ward (36.8%) and private ward (36.8%). Almost on full-time (94.7%), more than half were diploma holders (57.9%) with 1 to 5 years of experience (47.4%). Majority (84.2%) were involved in wound treatment and management, there were significant association between years of experience and wound classification, wound treatment, treatment failure and treatment failure factors. Conclusion: Wound care practices require accurate knowledge and assessment skills, a better understanding of wound management provides comprehensible, rapid patient wound care and minimizes patient mortality as well as reduces health services financial costs.
Background: Job satisfaction is a significant indicator of the way nurses feel about their profession, the efforts to perform their professional duties, or otherwise abandons it willingly. Method: cross-sectional research design approach was used to assess the job satisfaction and the associated factors among 300 hundred nurses. Data was analyzed using descriptive statistics and kruskal wallis test for association between the socio-demographic variables and job satisfaction at significance level of 0.05 Result: About 1/3 of the respondents (31%) reported gross dissatisfaction with their job, 0% reported being well satisfaction while (68.7%) respondents reported moderate satisfaction with their job. Across items on the scale, gross dissatisfaction was noted on key managerial factors and the salary of the workers. Job satisfaction was associated with specialty (p<0.018), gender (P<0.002) and age (P<0.000) of Nurses. Conclusion: majority of the respondents were moderately satisfied with their job but grossly dissatisfied with salary and administrative roles like communication flow.
Viral infections have always been of major concern in communities, health care settings and medical fields including radiotherapy and Radiology. Recently corona virus infection has attained global attention in the wake of covid-19 outbreak and consequently highlighted importance of viral prevention, diagnostic and therapeutic strategies to control and treat viral disease. In view of the recent events, the author reviewed the current and past literature to discuss contagious versus infectious viral transmission, as well as simple and effective ways of preventing the spread of viral diseases in community and health care setting so that this information can be used for preventing viral transmission at all levels. The article is written for a wide variety of audiences i.e. scientific and medical communities policy makers and general public.
The Coronavirus Disease – 2019 (COVID-19) is officially now a pandemic and not just a public health emergency of international concern as previously labelled. Worldwide, the new coronavirus has infected more than 4.9 million people and leaving more than 300,000 people dead in 188 countries. As countries of the world get locked down in an effort to contain the widespread of the virus, experts are concern about the global impacts of the pandemic on individuals, countries and the world at large. Millions of people are currently under quarantine across the globe. Many countries have responded by proclaiming a public health emergency, closed their borders and restrict incoming flights from high risk countries. This has grossly affected the travel plan of many. Several international programs, conferences, workshops and sporting activities are either postponed or cancelled. As the number of confirmed cases continues to escalate across the globe, hospitals seems to be running out of medical supplies, hospital spaces and personnel. Health workers are being overwhelmed by the numbers of people requesting for testing and treatment. Many of such health workers have been infected with the coronavirus and even lost their lives since the fight against COVID-19 started. Public health experts are also concerned about the huge medical wastes coming from the hospitals at this time and the adverse effects associated with improper management of such medical wastes, both at the hospital and community levels. The pandemic has also impacted negatively on the global economy. There have been serious crises in the stock market, with gross fall in the price of crude oil resulting in inflation and economic hardship among the populace. Many are currently out of job and as a result, the level of crime, protest and violence have continued to escalate in different parts of the world. The deaths of loved ones due to the coronavirus has left many emotionally traumatized. Nigeria, like other African countries is not spared of the ravaging effects of the pandemic, even as the government take strict measures to contain the virus. No doubt, this is very challenging, but the country is capable of surmounting the virus with the needed help from her international partners and cooperation from the citizenry. But if we as a people, remain complacent and continue with business as usual, without taking measures to flatten the curve, the disease will escalate too quickly beyond our capacity to handle and our health system will be overwhelmed and may collapse eventually. We cannot therefore afford to be complacent in our response to containing the pandemic.
Purpose: To investigate the effect of sulfur dioxide on the lung microbiota of healthy rats. Methods Fifteen male rats were randomly divided into high dose and low dose exposure group and control group. After 7 days of SO2 exposure, the lung tissues were obtained and the lung microbiota was identified by Illumina high-throughput sequencing. Results The microbial community of lung microbiota was significantly alternated in the exposure group and the dominant phylum changed from Firmicutes to Proteobacteria. In addition, the SO2 exposure caused the bronchial wall thickening and a large number of inflammatory cell infiltration in the lungs of rats in exposure groups. Conclusions The results suggest that SO2 can significantly alter the lung microbiota and pathological structure of the lungs.
Malaria is still considered globally as a leading cause of morbidity with Nigeria carrying the highest burden of 19%. Coinfection of malaria and Human Immunodeficiency Virus (HIV) accelerate disease progression of HIV/AIDS subjects. This study investigated the prevalence and predictors of malaria among HIV infected subjects attending the antiretroviral therapy Clinic at Federal the Medical Centre, Keffi, Nigeria. After ethical clearance, 200 whole blood specimens were collected from patients who gave informed consent and completed a self-structured questionnaire. The specimens were examined for malarial parasite using rapid kits and microscopy. The overall prevalence of the infection was 78/200 (39.0%). The prevalence was higher in male (44.7%) than female (34.0%) subjects. Those subjects aged < 20 years (54.5), male gender (44.7%), non-formal education holders (61.5%), farmers (62.5%), stream water users (48.1%), those that lives in rural setting (43.6%), those that do not use Insecticides Treated Nets (ITNs) (39.4%) and swampy environment dwellers (41.7%) were identified predictors for malaria infection in the area. All the predictors studied did not show any statistically significant difference with the infection but some arithmetic difference exists (P > 0.05). The 39.0% prevalence of malaria in HIV infected subjects is a public health concern. Therefore, Public health surveillance and health education among HIV population should be advocated to help eradicate malaria comes 2030. Further study that will characterize the genes of the parasite should be carried out.
This document presents a mathematical model to eliminate malaria transmission by breaking the life cycle of Anopheles mosquitoes. The model introduces two natural enemies - copepods to prey on mosquito larvae and tadpoles to prey on pupae. Differential equations were derived to model the growth of each mosquito life stage from egg to adult when under attack by these predators. Stability analysis of the disease-free equilibrium was conducted using equilibrium points, Beltrami's conditions, and Diekmann's conditions. The results indicate that introducing copepods and tadpoles makes the disease-free equilibrium stable, meaning the mosquito life cycle would be broken and no adult mosquitoes emerge to transmit malaria.
Spindle cell neoplasms usually occur in head, neck, orbit, soft tissues of scalp and along the upper aerodigestive tract. They are relatively uncommon in lower gastrointestinal tract and represent a distinct clinical entity. Increased awareness is required among colorectal surgeons and pathologists due to their benign nature & uncertain etiology, to avoid misdiagnosis of rectal cancer. Definitive diagnosis necessitates immunohistochemical analysis. We present an unusual case of spindle cell neoplasm of rectum in an asymptomatic elderly gentleman, detected on screening colonoscopy. Following thorough evaluation with MRI pelvis, CT scan thorax, abdomen, pelvis with contrast and multidisciplinary meeting discussion (MDT) at our institution, he was successfully treated with a specialized minimally invasive approach (TAMIS). Histopathology with immunohistochemistry confirmed the diagnosis of spindle cell neoplasm. As they are uncommon in colorectum & non-invasive, management and long-term follow-up is still under study. These lesions should be differentiated from other stromal tumours in GIT.
This document summarizes a study on the relationship between socio-demographic characteristics and the prevalence of brucellosis among community members in Mandera East Sub-County, Kenya. Blood samples from 420 respondents were tested for brucellosis using the Rose Bengal Plate Test (RBPT) and Serum Slow Agglutination Test (SSAT). The RBPT indicated a prevalence of 24.8% while the SSAT, a confirmatory test, indicated a prevalence of 14.3%. The study found the seroprevalence was higher among males (98% by RBPT and 98% by SSAT) and there was a significant relationship between gender and seroprevalence. Socio-demographic data
The Matrix metalloproteinase-9 is involved in several pathologies. Its strong presence in ocular pathologies explains our interest for its genetic variation in cataract, glaucoma and retinoblastoma in Senegal. MMP9 is highly polymorphic with cataract and glaucoma. 77 mutations were noted with 21 haplotypes for the entire population. The haplotype diversity Hd is 0.831 and the nucleotide diversity Pi is 0.016; k = 17.395. The polymorphism of the Matrix metalloproteinase-9 gene is associated with all three diseases and SNP 3918249 is found in both cataract and glaucoma.
This paper proposes the development of a software that performs the pre-diagnosis of malignant melanoma, spincellular carcinoma and basal-cell carcinoma. The software is divided into five modules, these being: digital imaging, analysis and processing, storage, feature extraction and classification by means of an Artificial Neural Network (ANN). The results shown the performance of the software for two different combination of activation functions in the network. With the use of spectroscopic techniques for the acquisition of images and the combination of non-linear and linear activation functions in the ANN, the software shows an effectiveness greater than 80%, concluding that it can be an effective tool as an aid in the diagnosis of cancer of skin.
Background: Tuberculous meningitis is defined as an inflammatory response to mycobacterial bacterial infection of the pia, arachnoid and CSF of the subarachnoid space. It is a dangerous form of extrapulmonary tuberculosis because it can cause permanent neurological disabilities and even death. Stroke is a devastating complication which further increase the morbidity and mortality in the disease. Matrix metalloproteinases are endopeptidases which degrade all the components of the extracellular matrix and thus have potential to disrupt blood brain barrier and cause CNS damage. Matrix metalloproteinases have been associated with pathophysiology of ischemic stroke. MMP levels in serum and CSF have also been seen to rise with advancing stage of TBM. So it is postulated that MMP may have role in the pathophysiology of stroke in TBM and may serve as a biomarker to predict stroke in TBM. Aims: To compare Serum Matrix metalloproteinase-9 in patients with Tuberculous Meningitis with and without Stroke and correlate it with various clinical, biochemical and radiological features of TBM. Methods: 40 Patients of probable or definite TBM and 40 age and sex matched patients of TBM with clinical stroke were enrolled in the study and formed two groups i.e. cases and controls. The two groups were compared for various clinical parameters, biochemical parameters (CSF cytology, glucose and protein), neuroimaging parameters and serum MMP-9 levels. Serum MMP-9 was estimated by ELISA method. Results: Serum MMP-9 levels were (224 ± 261.627 ng/ml) in cases and (157.23 ± 197.155 ng/ml) controls, which though higher in cases but no difference was statistically significant (p value 0.157) between two groups. Also there was no correlation between the serum MMP-9 levels and various clinical features (duration of illness, fever, headache, vomiting, weight loss, seizure, hemiparesis), CSF characteristics (protein, sugar and cytology) and radiological findings (tuberculoma, and hydrocephalus). Conclusion: we conclude that MMP-9 levels is not correlated with occurrence of stroke in TBM. MMP-9 levels were not increased with severity of disease, complications and outcomes.
This study aimed to determine factors influencing postnatal monitoring in the Bafang Health District of Cameroon. The study found that women who were informed of postnatal appointment dates by midwives, those who believed the appropriate period for follow-up was 6 weeks postpartum, and those who massaged their abdomen after childbirth were more likely to have knowledge of postnatal follow-up. In contrast, women with no knowledge of the appropriate periods for postnatal consultations were less likely to have knowledge. The study concluded that lack of knowledge about postnatal consultations and traditional practices are factors influencing postnatal follow-up in the district, and increased awareness campaigns are needed.
Aim: To highlight the challenge in the management of Arginosuccinic acidemia as well as demonstrate the importance of newborn screening for inborn errors of metabolism. Method: Report of two cases of neonatal onset ASA with encephalopathy and review of relevant literature. Conclusion: Early diagnosis and institution of appropriate intervention can significantly improve outcome. Routine newborn metabolic screening should not only be implemented universally, the result should be available promptly.
To form the basis of a respiratory disease model in rats by investigating the microbial distribution and composition in the lower respiratory tracts of normal rats. Methods: DNA was extracted from the intestine, trachea, bronchus and lung samples collected from healthy rats under sterile conditions. The 16S rDNA V4-V5 region was sequenced using Illumina high-throughput technology. Results: The sequencing results showed that there was no significant difference in abundance and species diversity of microbiota between the lower respiratory and the intestine. The microbiota structure analysis showed samples from lungs and intestinal shared similarity. However, the dominant species at the levels of phylum, family, and genus diverged. The similarity analysis showed that the lung microbiota were different from the intestines. The linear discriminant analysis showed significantly different species in different tissues; function prediction also showed different microbiota function in different tissues. Conclusions: These results suggest that bacterial colonization depends on the sample’s anatomical location. The human pathogen Acinetobacter lwoffii was also detected in the rat lower respiratory tract samples.
Hypertension and it's role of physiotherapy in it.Vishal kr Thakur
This particular slides consist of- what is hypertension,what are it's causes and it's effect on body, risk factors, symptoms,complications, diagnosis and role of physiotherapy in it.
This slide is very helpful for physiotherapy students and also for other medical and healthcare students.
Here is summary of hypertension -
Hypertension, also known as high blood pressure, is a serious medical condition that occurs when blood pressure in the body's arteries is consistently too high. Blood pressure is the force of blood pushing against the walls of blood vessels as the heart pumps it. Hypertension can increase the risk of heart disease, brain disease, kidney disease, and premature death.
VEDANTA AIR AMBULANCE SERVICES IN REWA AT A COST-EFFECTIVE PRICE.pdfVedanta A
Air Ambulance Services In Rewa works in close coordination with ground-based emergency services, including local Emergency Medical Services, fire departments, and law enforcement agencies.
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Mental Health and well-being Presentation. Exploring innovative approaches and strategies for enhancing mental well-being. Discover cutting-edge research, effective strategies, and practical methods for fostering mental well-being.
Unlocking the Secrets to Safe Patient Handling.pdfLift Ability
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Analysis of Heavy Metal Pollution Based on Two-Dimensional Diffusion Model
1. International Journal of Healthcare and Medical Sciences
ISSN(e): 2414-2999, ISSN(p): 2415-5233
Vol. 5, Issue. 1, pp: 1-6, 2019
URL: https://arpgweb.com/journal/journal/13
DOI: https://doi.org/10.32861/ijhms.51.1.6
Academic Research Publishing
Group
*Corresponding Author
1
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 [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. International Journal of Healthcare and Medical Sciences
2
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 Qiao, et al. [7],
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 [8] 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 [9] is conducted to
be:
3. International Journal of Healthcare and Medical Sciences
3
( )
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 [10]:
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 [11] 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. International Journal of Healthcare and Medical Sciences
4
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 [12] that based on the principle of least squares method [13] 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 same 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 [14]. 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.
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
5. International Journal of Healthcare and Medical Sciences
5
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.
(3) The paper lack of the data, the optimized model is not verified when introducing the model of the influence
factors.
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