Journal & Issues

Volume 27 (2022): Issue 4 (December 2022)

Volume 27 (2022): Issue 3 (September 2022)

Volume 27 (2022): Issue 2 (June 2022)

Volume 27 (2022): Issue 1 (March 2022)

Volume 26 (2021): Issue 4 (December 2021)

Volume 26 (2021): Issue 3 (September 2021)

Volume 26 (2021): Issue 2 (June 2021)

Volume 26 (2021): Issue 1 (March 2021)

Volume 25 (2020): Issue 4 (December 2020)

Volume 25 (2020): Issue 3 (September 2020)

Volume 25 (2020): Issue 2 (June 2020)

Volume 25 (2020): Issue 1 (March 2020)

Volume 24 (2019): Issue 4 (December 2019)

Volume 24 (2019): Issue 3 (September 2019)

Volume 24 (2019): Issue 2 (June 2019)

Volume 24 (2019): Issue 1 (March 2019)

Volume 23 (2018): Issue 4 (November 2018)

Volume 23 (2018): Issue 3 (August 2018)

Volume 23 (2018): Issue 2 (May 2018)

Volume 23 (2018): Issue 1 (February 2018)

Volume 22 (2017): Issue 4 (December 2017)

Volume 22 (2017): Issue 3 (August 2017)

Volume 22 (2017): Issue 2 (May 2017)

Volume 22 (2017): Issue 1 (February 2017)

Volume 21 (2016): Issue 4 (December 2016)

Volume 21 (2016): Issue 3 (August 2016)

Volume 21 (2016): Issue 2 (May 2016)

Volume 21 (2016): Issue 1 (February 2016)

Volume 20 (2015): Issue 4 (December 2015)

Volume 20 (2015): Issue 3 (August 2015)

Volume 20 (2015): Issue 2 (May 2015)

Volume 20 (2015): Issue 1 (February 2015)

Volume 19 (2014): Issue 4 (December 2014)

Volume 19 (2014): Issue 3 (August 2014)

Volume 19 (2014): Issue 2 (May 2014)

Volume 19 (2014): Issue 1 (February 2014)

Volume 18 (2013): Issue 4 (December 2013)

Volume 18 (2013): Issue 3 (August 2013)

Volume 18 (2013): Issue 2 (June 2013)

Volume 18 (2013): Issue 1 (March 2013)

Journal Details
Format
Journal
eISSN
2353-9003
First Published
19 Apr 2013
Publication timeframe
4 times per year
Languages
English

Search

Volume 27 (2022): Issue 1 (March 2022)

Journal Details
Format
Journal
eISSN
2353-9003
First Published
19 Apr 2013
Publication timeframe
4 times per year
Languages
English

Search

15 Articles
Open Access

Vertical Extension of a Multi-Storey Reinforced Concrete Building

Published Online: 17 Mar 2022
Page range: 1 - 20

Abstract

Abstract

The global population is increasing annually; thus, there is a need for more housing and buildings worldwide. As cities grow outward and buildable lands become scarce, it is necessary to increase the height of existing buildings in cities, especially where the height of the buildings is low. For crowded cities, the storey extension is an increasingly popular measure that can meet market demand for centrally located houses. This paper examines the possibility of the vertical extension of an existing (reference) reinforced concrete building in Gävle in Sweden. The StruSoft FEM-Design program is employed to carry out the research. The building is firstly modelled, analysed and designed completely. Thereafter, a storey extension is conducted vertically. The stresses and utilisation ratios of the load-bearing elements of the reference and extended buildings are assessed. It is found that some of the load-bearing elements of the building after the extension need strengthening. Different practical strengthening solutions are proposed. It is concluded that the building can successfully withstand the vertical extension after applying these proposed solutions. The maximum vertical reaction forces of the reference and extended buildings are obtained and compared. A comparison of the deflections of the buildings is made. The structural stability of the buildings is evaluated as well.

Keywords

  • vertical extension
  • reinforced concrete building
  • utilisation ratio
  • reaction force
  • deflection
Open Access

An Effect of Binary Fluid on the Thermal Performance of Pulsation Heat Pipe

Published Online: 17 Mar 2022
Page range: 21 - 34

Abstract

Abstract

A pulsation heat pipe is an efficient heat pipe used in many engineering applications. This study aims to test the effect of working fluids on the thermal performance of pulsation heat pipe. Seven turned pulsation heat pipes were designed and manufactured from a copper pipe with a 3.5 mm inner diameter. The lengths of an evaporation part, an adiabatic passage, and a condenser part were 300 mm, 210 mm, and 300 mm, respectively. In this study, three different fluids were used as the working fluid: distilled water, methanol, and binary fluid (a mixture of water and methanol) with a 50% filling ratio. Compared to water, the experimental results suggested that methanol had a better thermal performance when used as a working fluid in the PHP. On the other hand, a binary fluid enhanced the lower thermal performance of water (29% reduction in the thermal resistance and a 20% increase in the effective thermal conductivity of the PHP).

Keywords

  • binary fluid
  • oscillation heat pipe
  • two phase flow
  • thermal resistance
  • heat transfer
Open Access

Crack Growth Diagnostic of Ball Bearing Using Vibration Analysis

Published Online: 17 Mar 2022
Page range: 35 - 45

Abstract

Abstract

It is known that supported ball bearings have great effects on the vibrations of the gear transmission system, above in all the presence of local faults as well as the crack growths. For this purpose, this paper focuses on shock and vibration crack growth diagnostic of ball bearing using vibration analysis. Our work is devoted first to a study the static behaviour of the ball bearing by determining the stress, strain and displacement, then its dynamic behaviour by determining the first four natural frequencies. Secondly, a dynamic analysis study of the bearing was carried with defects as a function of crack size and location. The obtained results clearly show that the natural frequencies decrease in a non-linear way with the growth of the length of the crack, on the other hand the stress increases with the presence of the singular points of the crack. Finally, this residual decrease in natural frequencies can be used as an indicator of the state of failure, as well as a parameter used for the diagnosis and screening, and to highlight the fatigue life of the bearing

Keywords

  • ball bearing
  • vibration analysis
  • frequency
  • cracking
  • diagnosis
  • fatigue life
Open Access

Improvement of the Graphical Method for Plotting the Shear and Moment Diagrams for Members Subjected to Linearly Varying Loads

Published Online: 17 Mar 2022
Page range: 46 - 66

Abstract

Abstract

This study presents an improvement of the graphical method for plotting the shear and moment diagrams for the structural members under linearly varying loads (triangular and trapezoidal loads). Based on the parabolic nature of the shear function, when the loading varies linearly, and on the relations among load, shear, and moment, a mathematical equation is developed to locate the zero-shear point, while a geometric technique is presented to calculate the parabolic shear area. Five comprehensive examples of beams loaded with linearly varying loads are selected to illustrate the steps of the solution for the proposed techniques. The results demonstrated the applicability of the presented method, and gave exact diagrams compared with the basic graphical method. It is concluded that the proposed improved method is generally more convenient, less time-consuming, and has less computational efforts because it does not require sectioning, solving equilibrium equations, and quadratic formulas compared with the basic graphical method.

Keywords

  • shear diagrams
  • moment diagram
  • graphical method
  • improvement
  • varying loads
Open Access

Friction Spot Lap Joining of Aluminum Alloy AA6061 to Pre-Holed and Threaded Carbon Steel AISI 1006

Published Online: 17 Mar 2022
Page range: 67 - 77

Abstract

Abstract

This work addresses to joining aluminum alloy AA6061 to carbon steel AISI 1006 sheets using the friction spot joining technique. The steel sheets were pre-holed and threaded with an internal M6 thread. The joining process was carried out by extruding the aluminum through the steel hole and thread using a rotating tool with friction between the tool and aluminum. Three process parameters were used: pre-heating time, rotating speed and plunging depth of the tool, with four levels for each parameter. The results indicated that the two materials joined by a micro-scale mechanical interlock at an interface line of a width ranged between 0.7 to ~ 2.5 mm. The joint’s shear force reached a minimum and maximum value of 2000 and 2500 N, respectively. The plunging depth was the most effective factor affecting the amount of the extruded aluminum and the joint’s shear force.

Keywords

  • AA6061
  • AISI 1006
  • friction spot joining
  • aluminum extrusion
Open Access

Transient Flow Through a Porous Channel with Ramped Pressure Gradient and Velocity Slip Boundary Condition

Published Online: 17 Mar 2022
Page range: 78 - 90

Abstract

Abstract

A transient flow formation of an incompressible fluid through a horizontal porous channel assuming a ramped pressure gradient is considered with the velocity slip boundary conditions. The flow is a laminar flow caused by ramped pressure gradient along the flow direction. The equation governing the flow is modeled, and solved by the Laplace transformation technique to obtain a semi-analytical solution under slip boundary conditions. It was noted that the flow velocity increases as the slip parameter is increased.

Keywords

  • transient flow
  • velocity slip
  • ramped pressure gradient
  • Riemann-Sum approximation technique
Open Access

Difference Scheme for Differential-Difference Problems with Small Shifts Arising in Computational Model of Neuronal Variability

Published Online: 17 Mar 2022
Page range: 91 - 106

Abstract

Abstract

The solution of differential-difference equations with small shifts having layer behaviour is the subject of this study. A difference scheme is proposed to solve this equation using a non-uniform grid. With the non-uniform grid, finite - difference estimates are derived for the first and second-order derivatives. Using these approximations, the given equation is discretized. The discretized equation is solved using the tridiagonal system algorithm. Convergence of the scheme is examined. Various numerical simulations are presented to demonstrate the validity of the scheme. In contrast to other techniques, maximum errors in the solution are organized to support the method. The layer behaviour in the solutions of the examples is depicted in graphs.

Keywords

  • non-uniform grid
  • differential-difference equation
  • boundary layer
Open Access

Thermosensitive Response of a Functionally Graded Cylinder with Fractional Order Derivative

Published Online: 17 Mar 2022
Page range: 107 - 124

Abstract

Abstract

The present paper deals with thermal behaviour analysis of an axisymmetric functionally graded thermosensitive hollow cylinder. The system of coordinates are expressed in cylindrical-polar form. The heat conduction equation is of time-fractional order 0 < α ≤ 2, subjected to the effect of internal heat generation. Convective boundary conditions are applied to inner and outer curved surfaces whereas heat dissipates following Newton’s law of cooling. The lower surface is subjected to heat flux, whereas the upper surface is thermally insulated. Kirchhoff’s transformation is used to remove the nonlinearity of the heat equation and further it is solved to find temperature and associated stresses by applying integral transformation method. For numerical analysis a ceramic-metal-based functionally graded material is considered and the obtained results of temperature distribution and associated stresses are presented graphically.

Keywords

  • time fractional
  • thick hollow cylinder
  • thermal stresses
  • internal heat generation
  • FGMs
  • thermosenstive
Open Access

Unsteady Electro-Magneto Hydrodynamic Flow and Heat Transfer of Two Ionized Fluids in a Rotating System with Hall Currents

Published Online: 17 Mar 2022
Page range: 125 - 145

Abstract

Abstract

An unsteady flow and heat transmission of ionized gases via a horizontal channel enclosed by non-conducting plates in a rotating framework with Hall currents is examined using electro-magnetohydrodynamic (EMHD) two-fluid heat flow. The Hall current impact is taken into account by assuming that the gases are totally ionized, the applied transverse magnetic field is very strong. For temperature and velocity distributions in two-fluid flow regions, the governing equations are solved analytically. For numerous physical parameters such as the Hartmann number, Hall parameter, rotation parameter, viscosity ratio, and so on, numerical solutions are visually displayed. It was discovered that an increase in temperature in the two regions is caused by the thermal conductivity ratio. It was also realized that an increase in rate of heat transfer coefficient at the plates is caused by either the Hartman number or the Hall parameter.

Keywords

  • unsteady flow
  • magnetic and electric fields
  • immiscible flow
  • plasma
  • Hall effect
  • rotating frame
  • heat transfer
  • insulating plates
Open Access

Key Determinants for High-Alloyed Cast Irons for Mechanical Engineering

Published Online: 17 Mar 2022
Page range: 146 - 167

Abstract

Abstract

This work presents the factors determining cast iron, and particularly austenitic high-alloy cast iron as a construction material, which is ranked among the leading casting alloys of iron with carbon, mainly due to its very good service properties, which makes it dedicated as a material for automotive castings, pipe and fitting castings and components resistant to elevated temperatures, corrosion and abrasive wear. Construction materials currently used in industry have increasingly better properties and their potential is depleting quickly. This forces the manufacturers to adjust the requirements and production capabilities of cast iron using the most modern technologies that give the expected beneficial economic and operating effects. The paper quotes the results of research in the field of the offered technologies that give special surface features to machine parts made of cast iron by modernising the parameters of the technological process of obtaining high-alloy austenitic cast iron, i.e., by applying coatings, as well as by appropriate surface treatment, the aim of which is and reinforce the material surface with those properties which are important in a given application.

Keywords

  • alloyed cast iron
  • wear
  • machining conditions
  • alloying additives
  • coatings
  • roughness
Open Access

Newtonian Heating Effect on Heat Absorbing Unsteady MHD Radiating and Chemically Reacting Free Convection Flow Past an Oscillating Vertical Porous Plate

Published Online: 17 Mar 2022
Page range: 168 - 187

Abstract

Abstract

In this article, we have discussed in detail the effect of Newtonian heating on MHD unsteady free convection boundary layer flow past an oscillating vertical porous plate embedded in a porous medium with thermal radiation, chemical reaction and heat absorption. The governing PDEs of the model together with related initial and boundary conditions have been solved numerically by the finite element method. The dimensionless velocity, temperature and concentration profiles are analyzed graphically due to the effects of key parameters in the concerned model problem. Computed results for the skin friction coefficient, Nusselt number and Sherwood number are put in tabular form. It is observed that the thermal and mass buoyancy effects support the velocity whilst a reverse effect is noticed when the strength of the magnetic field is increased. The velocity and temperature enhances with an increase in the Newtonian heating and thermal radiation whilst a reverse effect is observed with an increase in the Prandtl number and heat absorption parameter. Increasing Schmidt number and chemical reaction parameter tends to depreciate both velocity and concentration. The Newtonian heating, thermal radiation and magnetic field tends to decrease in the skin friction. The Nusselt number increases with increasing Newtonian heating and heat absorption parameters. An increase in the Schmidt number and chemical reaction rate tends to improve the Sherwood number.

Keywords

  • Newtonian heating
  • radiation parameter
  • chemical reaction rate
  • oscillating plate
  • heat absorption parameter
Open Access

Effect of MHD on Unsteady Oscillatory Couette Flow Through Porous Media

Published Online: 17 Mar 2022
Page range: 188 - 202

Abstract

Abstract

This paper describes the effects of a magnetic field on unsteady free convection oscillatory systems. When temperature and species concentration fluctuate with time around a non-zero constant, “Couette flow” across a porous medium occurs. The system of non-linear ODEs that governs the flow is solved analytically using the perturbation approach because the amplitude of fluctuations is very tiny. Mean flow and transient velocity, transient concentration, transient temperature, heat transfer, mean skin friction and phase and amplitude of skin friction. All have approximate solutions. The influence of different parameters on flow characteristics has been specified and discussed.

Keywords

  • MHD
  • porous media
  • free convection
  • Couette flow
Open Access

An Extended Finite Difference Method for Singular Perturbation Problems on a Non-Uniform Mesh

Published Online: 17 Mar 2022
Page range: 203 - 214

Abstract

Abstract

An extended second order finite difference method on a variable mesh is proposed for the solution of a singularly perturbed boundary value problem. A discrete equation is achieved on the non uniform mesh by extending the first and second order derivatives to the higher order finite differences. This equation is solved efficiently using a tridiagonal solver. The proposed method is analysed for convergence, and second order convergence is derived. Model examples are solved by the proposed scheme and compared with available methods in the literature to uphold the method.

Keywords

  • non uniform grid
  • finite difference method
  • singular perturbation
  • boundary layer
Open Access

Effect of Biodiesel Blended Fuel on the Performance and Emission Characteristics of Diesel Engines – A Review

Published Online: 17 Mar 2022
Page range: 215 - 231

Abstract

Abstract

The internal combustion engine plays a vital role in transportation, industry, and shipping. However, diesel as one of the main fuels for internal combustion engines, caused many environmental and human health problems. In order to solve the problems, more researchers have been committed to the research of alternative fuels. Biodiesel is a renewable, sustainable alternative fuel, and its characteristics are similar to traditional diesel. It can be mixed with pure diesel. It has been found that a mix with pure diesel in a certain ratio can effectively reduce the negative effects caused by its characteristics, improve the combustion performance, and reduce the NOx and PM emissions. This article mainly reviews the effects of the mixture of biodiesel and diesel on engine combustion characteristics and exhaust emissions, including three parts: part (1) summarizes and analyzes the biodiesel’s production and characteristics, part (2) analyzes the engine’s performance under different working conditions, and part (3) studies and analyzes the exhaust emission under different working conditions.

Keywords

  • biodiesel
  • Diesel engine
  • fuel properties
  • engine performance
  • exhaust emission
Open Access

Experimental Regulating Parameters of Bladder-Type Hydraulic Accumulator

Published Online: 17 Mar 2022
Page range: 232 - 243

Abstract

Abstract

Experimental regulating parameters of the non-stationary expansion of air inside a bladder-type hydraulic accumulator, working with the simple short pipeline, are presented in the paper. The technique of continuous online monitoring of changes in time of volume and absolute air pressure inside the hydraulic accumulator during the discharge process has been improved. Three series of experimental studies of transient gas processes inside the accumulator at different values of the average volume flow rate are made. Tendencies of change of the integral parameters of the hydraulic accumulator are obtained and analyzed depending on the serial number of the discharge cycle. A general dependence of dimensionless storage volume Kreg on the polytropic index n in series # 1–3, approximated by single power-law dependence, is obtained. The systematic changes of integral parameters in each subsequent discharge cycle can be explained by the non-stationary transient thermodynamic processes in air inside the accumulator until the thermodynamic equilibrium with the ambient air parameters is reached.

Keywords

  • discharge cycle
  • hydraulic accumulator
  • non-stationary expansion
  • polytropic index
  • storage volume
15 Articles
Open Access

Vertical Extension of a Multi-Storey Reinforced Concrete Building

Published Online: 17 Mar 2022
Page range: 1 - 20

Abstract

Abstract

The global population is increasing annually; thus, there is a need for more housing and buildings worldwide. As cities grow outward and buildable lands become scarce, it is necessary to increase the height of existing buildings in cities, especially where the height of the buildings is low. For crowded cities, the storey extension is an increasingly popular measure that can meet market demand for centrally located houses. This paper examines the possibility of the vertical extension of an existing (reference) reinforced concrete building in Gävle in Sweden. The StruSoft FEM-Design program is employed to carry out the research. The building is firstly modelled, analysed and designed completely. Thereafter, a storey extension is conducted vertically. The stresses and utilisation ratios of the load-bearing elements of the reference and extended buildings are assessed. It is found that some of the load-bearing elements of the building after the extension need strengthening. Different practical strengthening solutions are proposed. It is concluded that the building can successfully withstand the vertical extension after applying these proposed solutions. The maximum vertical reaction forces of the reference and extended buildings are obtained and compared. A comparison of the deflections of the buildings is made. The structural stability of the buildings is evaluated as well.

Keywords

  • vertical extension
  • reinforced concrete building
  • utilisation ratio
  • reaction force
  • deflection
Open Access

An Effect of Binary Fluid on the Thermal Performance of Pulsation Heat Pipe

Published Online: 17 Mar 2022
Page range: 21 - 34

Abstract

Abstract

A pulsation heat pipe is an efficient heat pipe used in many engineering applications. This study aims to test the effect of working fluids on the thermal performance of pulsation heat pipe. Seven turned pulsation heat pipes were designed and manufactured from a copper pipe with a 3.5 mm inner diameter. The lengths of an evaporation part, an adiabatic passage, and a condenser part were 300 mm, 210 mm, and 300 mm, respectively. In this study, three different fluids were used as the working fluid: distilled water, methanol, and binary fluid (a mixture of water and methanol) with a 50% filling ratio. Compared to water, the experimental results suggested that methanol had a better thermal performance when used as a working fluid in the PHP. On the other hand, a binary fluid enhanced the lower thermal performance of water (29% reduction in the thermal resistance and a 20% increase in the effective thermal conductivity of the PHP).

Keywords

  • binary fluid
  • oscillation heat pipe
  • two phase flow
  • thermal resistance
  • heat transfer
Open Access

Crack Growth Diagnostic of Ball Bearing Using Vibration Analysis

Published Online: 17 Mar 2022
Page range: 35 - 45

Abstract

Abstract

It is known that supported ball bearings have great effects on the vibrations of the gear transmission system, above in all the presence of local faults as well as the crack growths. For this purpose, this paper focuses on shock and vibration crack growth diagnostic of ball bearing using vibration analysis. Our work is devoted first to a study the static behaviour of the ball bearing by determining the stress, strain and displacement, then its dynamic behaviour by determining the first four natural frequencies. Secondly, a dynamic analysis study of the bearing was carried with defects as a function of crack size and location. The obtained results clearly show that the natural frequencies decrease in a non-linear way with the growth of the length of the crack, on the other hand the stress increases with the presence of the singular points of the crack. Finally, this residual decrease in natural frequencies can be used as an indicator of the state of failure, as well as a parameter used for the diagnosis and screening, and to highlight the fatigue life of the bearing

Keywords

  • ball bearing
  • vibration analysis
  • frequency
  • cracking
  • diagnosis
  • fatigue life
Open Access

Improvement of the Graphical Method for Plotting the Shear and Moment Diagrams for Members Subjected to Linearly Varying Loads

Published Online: 17 Mar 2022
Page range: 46 - 66

Abstract

Abstract

This study presents an improvement of the graphical method for plotting the shear and moment diagrams for the structural members under linearly varying loads (triangular and trapezoidal loads). Based on the parabolic nature of the shear function, when the loading varies linearly, and on the relations among load, shear, and moment, a mathematical equation is developed to locate the zero-shear point, while a geometric technique is presented to calculate the parabolic shear area. Five comprehensive examples of beams loaded with linearly varying loads are selected to illustrate the steps of the solution for the proposed techniques. The results demonstrated the applicability of the presented method, and gave exact diagrams compared with the basic graphical method. It is concluded that the proposed improved method is generally more convenient, less time-consuming, and has less computational efforts because it does not require sectioning, solving equilibrium equations, and quadratic formulas compared with the basic graphical method.

Keywords

  • shear diagrams
  • moment diagram
  • graphical method
  • improvement
  • varying loads
Open Access

Friction Spot Lap Joining of Aluminum Alloy AA6061 to Pre-Holed and Threaded Carbon Steel AISI 1006

Published Online: 17 Mar 2022
Page range: 67 - 77

Abstract

Abstract

This work addresses to joining aluminum alloy AA6061 to carbon steel AISI 1006 sheets using the friction spot joining technique. The steel sheets were pre-holed and threaded with an internal M6 thread. The joining process was carried out by extruding the aluminum through the steel hole and thread using a rotating tool with friction between the tool and aluminum. Three process parameters were used: pre-heating time, rotating speed and plunging depth of the tool, with four levels for each parameter. The results indicated that the two materials joined by a micro-scale mechanical interlock at an interface line of a width ranged between 0.7 to ~ 2.5 mm. The joint’s shear force reached a minimum and maximum value of 2000 and 2500 N, respectively. The plunging depth was the most effective factor affecting the amount of the extruded aluminum and the joint’s shear force.

Keywords

  • AA6061
  • AISI 1006
  • friction spot joining
  • aluminum extrusion
Open Access

Transient Flow Through a Porous Channel with Ramped Pressure Gradient and Velocity Slip Boundary Condition

Published Online: 17 Mar 2022
Page range: 78 - 90

Abstract

Abstract

A transient flow formation of an incompressible fluid through a horizontal porous channel assuming a ramped pressure gradient is considered with the velocity slip boundary conditions. The flow is a laminar flow caused by ramped pressure gradient along the flow direction. The equation governing the flow is modeled, and solved by the Laplace transformation technique to obtain a semi-analytical solution under slip boundary conditions. It was noted that the flow velocity increases as the slip parameter is increased.

Keywords

  • transient flow
  • velocity slip
  • ramped pressure gradient
  • Riemann-Sum approximation technique
Open Access

Difference Scheme for Differential-Difference Problems with Small Shifts Arising in Computational Model of Neuronal Variability

Published Online: 17 Mar 2022
Page range: 91 - 106

Abstract

Abstract

The solution of differential-difference equations with small shifts having layer behaviour is the subject of this study. A difference scheme is proposed to solve this equation using a non-uniform grid. With the non-uniform grid, finite - difference estimates are derived for the first and second-order derivatives. Using these approximations, the given equation is discretized. The discretized equation is solved using the tridiagonal system algorithm. Convergence of the scheme is examined. Various numerical simulations are presented to demonstrate the validity of the scheme. In contrast to other techniques, maximum errors in the solution are organized to support the method. The layer behaviour in the solutions of the examples is depicted in graphs.

Keywords

  • non-uniform grid
  • differential-difference equation
  • boundary layer
Open Access

Thermosensitive Response of a Functionally Graded Cylinder with Fractional Order Derivative

Published Online: 17 Mar 2022
Page range: 107 - 124

Abstract

Abstract

The present paper deals with thermal behaviour analysis of an axisymmetric functionally graded thermosensitive hollow cylinder. The system of coordinates are expressed in cylindrical-polar form. The heat conduction equation is of time-fractional order 0 < α ≤ 2, subjected to the effect of internal heat generation. Convective boundary conditions are applied to inner and outer curved surfaces whereas heat dissipates following Newton’s law of cooling. The lower surface is subjected to heat flux, whereas the upper surface is thermally insulated. Kirchhoff’s transformation is used to remove the nonlinearity of the heat equation and further it is solved to find temperature and associated stresses by applying integral transformation method. For numerical analysis a ceramic-metal-based functionally graded material is considered and the obtained results of temperature distribution and associated stresses are presented graphically.

Keywords

  • time fractional
  • thick hollow cylinder
  • thermal stresses
  • internal heat generation
  • FGMs
  • thermosenstive
Open Access

Unsteady Electro-Magneto Hydrodynamic Flow and Heat Transfer of Two Ionized Fluids in a Rotating System with Hall Currents

Published Online: 17 Mar 2022
Page range: 125 - 145

Abstract

Abstract

An unsteady flow and heat transmission of ionized gases via a horizontal channel enclosed by non-conducting plates in a rotating framework with Hall currents is examined using electro-magnetohydrodynamic (EMHD) two-fluid heat flow. The Hall current impact is taken into account by assuming that the gases are totally ionized, the applied transverse magnetic field is very strong. For temperature and velocity distributions in two-fluid flow regions, the governing equations are solved analytically. For numerous physical parameters such as the Hartmann number, Hall parameter, rotation parameter, viscosity ratio, and so on, numerical solutions are visually displayed. It was discovered that an increase in temperature in the two regions is caused by the thermal conductivity ratio. It was also realized that an increase in rate of heat transfer coefficient at the plates is caused by either the Hartman number or the Hall parameter.

Keywords

  • unsteady flow
  • magnetic and electric fields
  • immiscible flow
  • plasma
  • Hall effect
  • rotating frame
  • heat transfer
  • insulating plates
Open Access

Key Determinants for High-Alloyed Cast Irons for Mechanical Engineering

Published Online: 17 Mar 2022
Page range: 146 - 167

Abstract

Abstract

This work presents the factors determining cast iron, and particularly austenitic high-alloy cast iron as a construction material, which is ranked among the leading casting alloys of iron with carbon, mainly due to its very good service properties, which makes it dedicated as a material for automotive castings, pipe and fitting castings and components resistant to elevated temperatures, corrosion and abrasive wear. Construction materials currently used in industry have increasingly better properties and their potential is depleting quickly. This forces the manufacturers to adjust the requirements and production capabilities of cast iron using the most modern technologies that give the expected beneficial economic and operating effects. The paper quotes the results of research in the field of the offered technologies that give special surface features to machine parts made of cast iron by modernising the parameters of the technological process of obtaining high-alloy austenitic cast iron, i.e., by applying coatings, as well as by appropriate surface treatment, the aim of which is and reinforce the material surface with those properties which are important in a given application.

Keywords

  • alloyed cast iron
  • wear
  • machining conditions
  • alloying additives
  • coatings
  • roughness
Open Access

Newtonian Heating Effect on Heat Absorbing Unsteady MHD Radiating and Chemically Reacting Free Convection Flow Past an Oscillating Vertical Porous Plate

Published Online: 17 Mar 2022
Page range: 168 - 187

Abstract

Abstract

In this article, we have discussed in detail the effect of Newtonian heating on MHD unsteady free convection boundary layer flow past an oscillating vertical porous plate embedded in a porous medium with thermal radiation, chemical reaction and heat absorption. The governing PDEs of the model together with related initial and boundary conditions have been solved numerically by the finite element method. The dimensionless velocity, temperature and concentration profiles are analyzed graphically due to the effects of key parameters in the concerned model problem. Computed results for the skin friction coefficient, Nusselt number and Sherwood number are put in tabular form. It is observed that the thermal and mass buoyancy effects support the velocity whilst a reverse effect is noticed when the strength of the magnetic field is increased. The velocity and temperature enhances with an increase in the Newtonian heating and thermal radiation whilst a reverse effect is observed with an increase in the Prandtl number and heat absorption parameter. Increasing Schmidt number and chemical reaction parameter tends to depreciate both velocity and concentration. The Newtonian heating, thermal radiation and magnetic field tends to decrease in the skin friction. The Nusselt number increases with increasing Newtonian heating and heat absorption parameters. An increase in the Schmidt number and chemical reaction rate tends to improve the Sherwood number.

Keywords

  • Newtonian heating
  • radiation parameter
  • chemical reaction rate
  • oscillating plate
  • heat absorption parameter
Open Access

Effect of MHD on Unsteady Oscillatory Couette Flow Through Porous Media

Published Online: 17 Mar 2022
Page range: 188 - 202

Abstract

Abstract

This paper describes the effects of a magnetic field on unsteady free convection oscillatory systems. When temperature and species concentration fluctuate with time around a non-zero constant, “Couette flow” across a porous medium occurs. The system of non-linear ODEs that governs the flow is solved analytically using the perturbation approach because the amplitude of fluctuations is very tiny. Mean flow and transient velocity, transient concentration, transient temperature, heat transfer, mean skin friction and phase and amplitude of skin friction. All have approximate solutions. The influence of different parameters on flow characteristics has been specified and discussed.

Keywords

  • MHD
  • porous media
  • free convection
  • Couette flow
Open Access

An Extended Finite Difference Method for Singular Perturbation Problems on a Non-Uniform Mesh

Published Online: 17 Mar 2022
Page range: 203 - 214

Abstract

Abstract

An extended second order finite difference method on a variable mesh is proposed for the solution of a singularly perturbed boundary value problem. A discrete equation is achieved on the non uniform mesh by extending the first and second order derivatives to the higher order finite differences. This equation is solved efficiently using a tridiagonal solver. The proposed method is analysed for convergence, and second order convergence is derived. Model examples are solved by the proposed scheme and compared with available methods in the literature to uphold the method.

Keywords

  • non uniform grid
  • finite difference method
  • singular perturbation
  • boundary layer
Open Access

Effect of Biodiesel Blended Fuel on the Performance and Emission Characteristics of Diesel Engines – A Review

Published Online: 17 Mar 2022
Page range: 215 - 231

Abstract

Abstract

The internal combustion engine plays a vital role in transportation, industry, and shipping. However, diesel as one of the main fuels for internal combustion engines, caused many environmental and human health problems. In order to solve the problems, more researchers have been committed to the research of alternative fuels. Biodiesel is a renewable, sustainable alternative fuel, and its characteristics are similar to traditional diesel. It can be mixed with pure diesel. It has been found that a mix with pure diesel in a certain ratio can effectively reduce the negative effects caused by its characteristics, improve the combustion performance, and reduce the NOx and PM emissions. This article mainly reviews the effects of the mixture of biodiesel and diesel on engine combustion characteristics and exhaust emissions, including three parts: part (1) summarizes and analyzes the biodiesel’s production and characteristics, part (2) analyzes the engine’s performance under different working conditions, and part (3) studies and analyzes the exhaust emission under different working conditions.

Keywords

  • biodiesel
  • Diesel engine
  • fuel properties
  • engine performance
  • exhaust emission
Open Access

Experimental Regulating Parameters of Bladder-Type Hydraulic Accumulator

Published Online: 17 Mar 2022
Page range: 232 - 243

Abstract

Abstract

Experimental regulating parameters of the non-stationary expansion of air inside a bladder-type hydraulic accumulator, working with the simple short pipeline, are presented in the paper. The technique of continuous online monitoring of changes in time of volume and absolute air pressure inside the hydraulic accumulator during the discharge process has been improved. Three series of experimental studies of transient gas processes inside the accumulator at different values of the average volume flow rate are made. Tendencies of change of the integral parameters of the hydraulic accumulator are obtained and analyzed depending on the serial number of the discharge cycle. A general dependence of dimensionless storage volume Kreg on the polytropic index n in series # 1–3, approximated by single power-law dependence, is obtained. The systematic changes of integral parameters in each subsequent discharge cycle can be explained by the non-stationary transient thermodynamic processes in air inside the accumulator until the thermodynamic equilibrium with the ambient air parameters is reached.

Keywords

  • discharge cycle
  • hydraulic accumulator
  • non-stationary expansion
  • polytropic index
  • storage volume

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