Annals of Materials Science & Engineering is a scholarly open access, peer reviewed journal dedicated to publish articles in all areas of Material Science such as aerospace engineering, mechanical engineering, metallurgical engineering, electrical/electronic engineering, civil engineering, fluid mechanics and instrumentation.
The aim of this journal is for scientists and academicians all over the world to support, share, and discuss various new issues and developments in different areas of Material Science & Engineering.
Annals of Materials Science & Engineering accepts original research articles, review articles, case reports, commentaries, clinical images and rapid communication on all the aspects of Material science and engineering.
Understanding Permeability of Hydraulic Fracture Networks A Sandbox Analog Mo...Renee Heldman
1) The document discusses an analog sandbox model that was created to better understand how permeability is affected by hydraulic fracturing networks. Fine-grained silica powder was used to represent low-permeability shale and injected with a similar fluid to those used in fracking to create fracture networks.
2) Cross sections showed the development of fractures and permeability was quantified. Permeability increased from 2.7 x 10-9 cm2 originally to up to 0.032 cm2 after fracturing, demonstrating the significant impact fractures can have. Fracture development depended on confining pressure and fluid viscosity.
3) The document reviews scaling relationships for modeling fracturing and discusses using silica flour as an analogue for
This document discusses plastic instability in uniaxial tension testing of materials. It defines true stress and strain, which account for changes in cross-sectional area during tension, and explains how they relate to engineering stress and strain. The condition for plastic instability is derived as the maximum in the true stress-strain curve where the rate of true stress increase with respect to true strain is equal to the true stress. This occurs at a uniform true strain value called the instability strain. Examples of true stress-strain curves and determinations of the strain hardening exponent are also provided.
International Journal of Engineering Inventions (IJEI) provides a multidisciplinary passage for researchers, managers, professionals, practitioners and students around the globe to publish high quality, peer-reviewed articles on all theoretical and empirical aspects of Engineering and Science.
1) The document describes a finite element analysis of the superplastic blow-forming of Ti-6Al-4V titanium alloy sheet into a closed ellip-cylindrical die.
2) The simulations investigate the effects of shear friction factor, die entry radius, die height, and die short-axis length on thickness distribution, stress, strain, and damage within the formed product.
3) The results confirm the suitability of using the DEFORMTM 3D finite element software to model superplastic blow-forming of Ti-6Al-4V titanium alloy.
The effect of disturbance factor on the stability of tunnels (Case study: Tun...IJRES Journal
Disturbance factor (D) is related to excavation method and cause damage and stress relief in the rock masses. The convergence and plastic zone around tunnels depends on the disturbance factor of rocks.This study has been in the tunnel No.2 of Kurdistan in NW of Iran which is composed of shale rocks. In tunnel modeling, different disturbance factors(0 to 1) areanalyzed using phase2 software and the amount of displacement and extent of plastic zone in around the tunnelis determined. The obtain results show that by increasing of disturbance factor, the displacement and plastic zone around the tunnel has increased and the most increase has occurred in disturbance factors 0.8 to 1. Therefore, for excavation of this tunnel, the blasting method should not be used and instead of it, the mechanical methods must be used.
Mathematical Relationships between the Compressive Strength and Some Other St...IOSR Journals
This document establishes mathematical relationships between the compressive strength and other properties (water absorption, flexural strength, and split tensile strength) of sand-quarry dust blocks through regression analysis. Tests were conducted on blocks with varying mix ratios of cement, sand, and quarry dust. Linear and quadratic models relating each additional property to compressive strength were developed. The models were found to have low standard error and high coefficient of determination, indicating they adequately predict relationships between compressive strength and other block properties. The relationships can be used when only compressive strength testing is conducted to estimate additional properties.
Stability Analysis of Journal Bearing Using Electro Rheological Fluid by Fini...ijsrd.com
in rotating machinery, the damping of structure which supports the rotating shaft has significant effect in machine vibration. Therefore by controlling the lubricant properties, the dynamic behavior of the system can be controlled. The objective of this paper is to study the dynamic behavior of a rotor supported by a journal bearing and fed with Electro-rheological (ER) fluid. ER fluids can be used to create ‘smart’ journal bearings & vibration controllers can be constructed to control the Stability of the ER fluid lubricated bearings. The ER fluid behaves like a Bingham fluid with a higher viscosity when electric field is applied, and restores its property when the field is removed. A reversible change in viscosity occurs in milliseconds with the electric field applied.
Understanding Permeability of Hydraulic Fracture Networks A Sandbox Analog Mo...Renee Heldman
1) The document discusses an analog sandbox model that was created to better understand how permeability is affected by hydraulic fracturing networks. Fine-grained silica powder was used to represent low-permeability shale and injected with a similar fluid to those used in fracking to create fracture networks.
2) Cross sections showed the development of fractures and permeability was quantified. Permeability increased from 2.7 x 10-9 cm2 originally to up to 0.032 cm2 after fracturing, demonstrating the significant impact fractures can have. Fracture development depended on confining pressure and fluid viscosity.
3) The document reviews scaling relationships for modeling fracturing and discusses using silica flour as an analogue for
This document discusses plastic instability in uniaxial tension testing of materials. It defines true stress and strain, which account for changes in cross-sectional area during tension, and explains how they relate to engineering stress and strain. The condition for plastic instability is derived as the maximum in the true stress-strain curve where the rate of true stress increase with respect to true strain is equal to the true stress. This occurs at a uniform true strain value called the instability strain. Examples of true stress-strain curves and determinations of the strain hardening exponent are also provided.
International Journal of Engineering Inventions (IJEI) provides a multidisciplinary passage for researchers, managers, professionals, practitioners and students around the globe to publish high quality, peer-reviewed articles on all theoretical and empirical aspects of Engineering and Science.
1) The document describes a finite element analysis of the superplastic blow-forming of Ti-6Al-4V titanium alloy sheet into a closed ellip-cylindrical die.
2) The simulations investigate the effects of shear friction factor, die entry radius, die height, and die short-axis length on thickness distribution, stress, strain, and damage within the formed product.
3) The results confirm the suitability of using the DEFORMTM 3D finite element software to model superplastic blow-forming of Ti-6Al-4V titanium alloy.
The effect of disturbance factor on the stability of tunnels (Case study: Tun...IJRES Journal
Disturbance factor (D) is related to excavation method and cause damage and stress relief in the rock masses. The convergence and plastic zone around tunnels depends on the disturbance factor of rocks.This study has been in the tunnel No.2 of Kurdistan in NW of Iran which is composed of shale rocks. In tunnel modeling, different disturbance factors(0 to 1) areanalyzed using phase2 software and the amount of displacement and extent of plastic zone in around the tunnelis determined. The obtain results show that by increasing of disturbance factor, the displacement and plastic zone around the tunnel has increased and the most increase has occurred in disturbance factors 0.8 to 1. Therefore, for excavation of this tunnel, the blasting method should not be used and instead of it, the mechanical methods must be used.
Mathematical Relationships between the Compressive Strength and Some Other St...IOSR Journals
This document establishes mathematical relationships between the compressive strength and other properties (water absorption, flexural strength, and split tensile strength) of sand-quarry dust blocks through regression analysis. Tests were conducted on blocks with varying mix ratios of cement, sand, and quarry dust. Linear and quadratic models relating each additional property to compressive strength were developed. The models were found to have low standard error and high coefficient of determination, indicating they adequately predict relationships between compressive strength and other block properties. The relationships can be used when only compressive strength testing is conducted to estimate additional properties.
Stability Analysis of Journal Bearing Using Electro Rheological Fluid by Fini...ijsrd.com
in rotating machinery, the damping of structure which supports the rotating shaft has significant effect in machine vibration. Therefore by controlling the lubricant properties, the dynamic behavior of the system can be controlled. The objective of this paper is to study the dynamic behavior of a rotor supported by a journal bearing and fed with Electro-rheological (ER) fluid. ER fluids can be used to create ‘smart’ journal bearings & vibration controllers can be constructed to control the Stability of the ER fluid lubricated bearings. The ER fluid behaves like a Bingham fluid with a higher viscosity when electric field is applied, and restores its property when the field is removed. A reversible change in viscosity occurs in milliseconds with the electric field applied.
RajeshKumarSahu_118CR0682_Tribological Studies of Glass Ceramics.pptxRAJESHKUMARSAHU27
Glass ceramics are polycrystalline materials produced by controlled crystallization of inorganic glasses. They contain residual glass and crystalline phases ranging from 0.5-99.5%. The properties are controlled by a two-stage heat treatment process of nucleation and crystallization. Testing showed the glass ceramic had a friction coefficient of 0.55 in dry conditions but no stationary regime was reached in wet conditions due to surface dissolution. The glass ceramic had a hardness of 6.3 GPa, elastic modulus of 76.8 GPa, and low Archard coefficient indicating low wear rate making it suitable for tile applications.
This document provides a comprehensive literature review on buckling analysis of laminated composite plates. It discusses the effects of boundary conditions, lamination arrangements, and plate theories on buckling load prediction. Both exact and numerical methods have been used to analyze buckling of laminated plates, with higher-order shear deformation plate theories providing more accurate results than classical plate theory. The review covers past research on various plate theories and analytical and numerical techniques for buckling analysis of laminated composite plates.
EFFECT OF SURFACE ROUGHNESS ON CHARACTERISTICS OF SQUEEZE FILM BETWEEN POROUS...IAEME Publication
In investigation aims to analyse the effect of transverse surface roughness on the squeeze film performance between porous rectangular plates. The associated differential equation is stochastically averaged making use of stochastic averaging method of Christensen and Tonder for transverse surface roughness. The equation is solved with appropriate boundary conditions to obtain the pressure and consequentlythe load bearing. The graphical results suggest that the bearing suffers because of transverse surface roughness. However the situation is slightly better in the case of
negatively skew roughness. Further variance (-ve) makes the situation furtherimproved even if moderate values of porosity are involved
The document defines and explains delayed cracking (DC), which is a type of material failure observed in advanced high strength steels with tensile strength above 800 MPa. DC occurs after an incubation time with or without external loading and is caused by the interaction of stresses or residual stresses with hydrogen. A deep drawing test is used to reveal the susceptibility of materials to DC by observing crack formation after varying incubation periods. The document also defines and explains other material characterization techniques such as X-ray diffraction (XRD) and deformation mechanisms like transformation induced plasticity and twinning induced plasticity, as well as dynamic recrystallization during material processing.
This document discusses applying the NCHRP-1-28 resilient modulus model to characterize blended unbound granular materials in Sudan. An experimental testing program measured the resilient modulus of blended samples using dynamic triaxial tests. The NCHRP-1-28 model was used to predict resilient modulus values, which showed good agreement with measured values, being 8-10% lower, providing conservative estimates. The materials tested included natural gravels blended with sand and crushed stone to meet gradation specifications for base materials. Measured properties like density, CBR and gradation are reported for the blended samples.
Peculiarities of irrecoverable straining in stress-drop testIJERA Editor
The paper concerns with analytical description of the phenomena observed in stress drop tests, namely, negative increment in plastic and creep deformation due to the sudden decrease in the acting stresses while the net stress remains positive. The model is developed in terms of the synthetic theory of irrecoverable deformation which has been generalized by introducing interplay between the deformation properties of material in the direction of acting load and opposite to it.
1. Surface engineering aims to modify the properties of material surfaces to improve functionality, such as corrosion resistance, wear resistance, and friction reduction. Common surface engineering techniques include coatings, thermal treatments, and surface texturing.
2. Controlling friction through surface texturing has gained interest, as microscale dimples or grooves can reduce friction. However, the effects of texturing parameters like shape, depth, width, and orientation on friction are still being studied. Surface roughness parameters provide a way to characterize topography but may not fully describe surfaces.
3. The document discusses various surface roughness parameters defined by ISO standards and how they can characterize surface topography features relevant to friction, such as peaks, valleys
Laboratory Assessment of Energy Efficiency in Vibraotry Compaction of Granula...Garrett Osborne
This document describes a laboratory test method for assessing the energy efficiency of vibratory compaction of granular materials. The method tracks material density and energy consumption during compaction using a vibratory hammer. Density-energy curves are produced to evaluate both the maximum achievable density and the compactibility, or rate of density increase with energy. Testing of a granular concrete mix found that higher compactibility leads to more energy-efficient compaction by reaching the target density with less total energy. This approach can guide selection of optimal compaction variables like frequency to improve sustainability of earthworks construction.
Predicting a mathematical models of some mechanical properties of concrete ...Alexander Decker
This document summarizes a study that aimed to develop mathematical models to predict mechanical properties
of concrete from non-destructive testing methods. Specifically, the study examined properties of normal strength
concrete and high-strength concrete with compressive strengths ranging from 20-100 MPa using Schmidt
hammer and ultrasonic pulse velocity tests at ages of 7, 28, 56, and 90 days. The results showed good
correlations between compressive strength and both test methods. Relationships were also found between
modulus of elasticity, rebound number, and age of concrete. The document provides background on types of
concrete and non-destructive testing methods.
To Experimental Study of Comparison and Development of Design for Rigid Pavem...Agriculture Journal IJOEAR
Abstract— The development of design have been discussed adopted various types methods use. The Hadi and Arfiadi Method presents a formulation for the optimum rigid road pavement design by genetic algorithm, a new method. The Westergaard’s Method determines the stresses in the rigid concrete slab and also the pressure-deformation curve which depend upon the relative stiffness of the slab and the subgrade. Razouki and Al-Muhana also developed stress charts similar to Westergaard’s method. The paper reveals that the effects on the maximum bending tensile stress are quite significant due to the modulus of subgrade reaction, modulus of elasticity of concrete and slab The Maharaj and Gill method have performed axisymmetric finite element analysis by varying parameters, the thickness of pavement, pressure and elastic modulus of subgrade. The advantage of this method is that four types of design charts have been presented which other methods have note done. First type of design chart has been plotted between thickness of pavement and nodal deflections for various pressures for a particular elastic modulus of soil. Second type of design chart has been plotted between thickness of pavement and element stress for various pressures for a particular elastic modulus of soil. The third type of design chart has been plotted between thickness of pavement and nodal deflections for various elastic moduli of subgrade for a particular pressure. Each of the design charts has three parameters. For two known parameters, the third parameter can be obtained.
A composite material can be defined as a combination of two or more materials that
gives better properties than those of the individual components used alone. In contrast to
metallic alloys, each material retains its separate chemical, physical, and mechanical
properties. The two constituents are reinforcement and a matrix. The main advantages of
composite materials are their high strength and stiffness combined with low density when
compared to classical materials. Micromechanical approach is found to be more suitable for
the analysis of composite materials because it studies the volume proportions of the
constituents for the desired lamina stiffness and strength.
A new method is developed for determining material hardness from depth sensing indentation tests. Both loading and unloading data are used to calculate Meyer hardness values, which agree well with conventional optical measurements. While the new method characterizes hardness even for elastic materials, the conventional mean contact pressure definition differs significantly from hardness for elastic materials. A relationship is found between work during loading and unloading that allows hardness to be calculated using only load-depth data.
This document discusses the mechanical properties of viscoelastic materials. It covers topics like stress/strain behavior, creep, toughness, reinforcement, and modifiers. It explains how polymer chemistry, structures, and properties influence product performance. Key factors that determine a plastic's mechanical response are intermolecular forces, temperature, time under load, degree of crystallinity, and molecular weight. A plastic can behave as an elastic solid, viscoelastic solid, viscoelastic fluid, or viscous fluid depending on these factors. Tests like tensile testing, impact testing, and dynamic mechanical analysis are used to characterize mechanical properties.
This document presents a new model for describing the pressure dependence of elastic properties in uncemented sedimentary rocks. The model incorporates effects of sedimentary compaction and critical porosity on how porosity and density change with increasing pressure. It fits laboratory data on various rock samples well over a wide range of pressures. The new model provides an improved way to predict pressure-dependent rock properties and interpret seismic data compared to previous theoretical models.
Dynamic Relaxation (DR) method is presented for the analysis of geometrically linear laterally loaded, rectangular laminated plates. The analysis uses the Mindlin plate theory which accounts for transverse shear deformations. A computer program has been compiled. The convergence and accuracy of the DR solutions of isotropic, orthotropic, and laminated plates for elastic small deflection response are established by comparison with different exact and approximate solutions. The present Dynamic Relaxation (DR) method shows a good agreement with other analytical and numerical methods used in the verification scheme. It was found that: The convergence and accuracy of the DR solution were dependent on several factors which include boundary conditions, mesh size and type, fictitious densities, damping coefficients, time increment and applied load. Also, the DR small deflection program using uniform meshes can be employed in the analysis of different thicknesses for isotropic, orthotropic or laminated plates under uniform loads in a fairly good accuracy.
This document summarizes a study on using electro-physical probing methods to diagnose the state of boundary lubrication layers in sliding bearings. The study developed a 4-wiring circuit to indirectly analyze boundary lubrication layer thickness based on measuring contact resistance parameters under different loads. Calculations were performed to estimate contact point radius and relate resistance measurements to boundary lubrication layer thickness based on tunneling conductivity theory. Testing of the method found that decreasing contact resistance to the theoretical contact resistance level indicates destruction of the boundary lubrication layer, representing a "dry" metal contact.
Comparative Analysis of Equivalent Material based on MFIDr. Amarjeet Singh
Polymers of the same family show distinct behavior with each other and because of this, the end prediction after molding the part is very difficult. Simulations result does not always match the product. For close substitution in absence of exactly known material composition, the equivalent grade of the same MFI may be used. However, the MFI is a poor indicator of the rheological behavior to be comprehend for accurate simulation. This research analyzes the appropriate parameters for the rheology of polymers, in the same class that are appropriate.
Establishing relationship between cbr with different soil propertieseSAT Journals
Abstract
In the flexible pavements sub-grade is considered to be an ideal layer to resist wheel load and its CBR value is considered as the strength measuring parameter. Conducting CBR test is an expensive and time consuming test, moreover it is very difficult to mould the sample at a desired in-situ density in the laboratory. Further, if the available soil is of poor quality, suitable additives are mixed with soil and resulting strength of soil is assessed by CBR value which is cumbersome. To overcome these problems, the other methods such as regression based models (simple & multiple) are used in this study. The soil properties like liquid limit, plastic limit, plasticity index, optimum moisture content, maximum dry density and percentage fineness of the soil (passing 75micron sieve) are determined for the soil collected from different areas of Bagalkot district and the models are developed for correlating soaked CBR value.
Keywords: CBR, regression models, liquid limit, plastic limit, plasticity index, optimum moisture content and maximum dry density.
This document presents a simple phenomenological approach to modeling nanoindentation creep using conventional spring and dashpot elements. It describes how creep, which is the time-dependent increase in depth under a held load, can be modeled for a variety of materials using Maxwell and Voigt models. Equations are presented that relate the depth increase over time to the elastic modulus and viscosity of the material being tested. A method is described for fitting experimental nanoindentation data, including holding periods, to these equations to determine material properties while accounting for creep. The approach aims to provide an accessible way to analyze creep in nanoindentation that can be incorporated into computer programs.
International Journal of Engineering Research and DevelopmentIJERD Editor
1) The study investigated the effect of aggregate size on the energy dissipation of plain concrete members subjected to static cyclic loading.
2) Testing found that smaller aggregate size (3/8") resulted in less energy dissipation compared to larger sizes (1/2", 3/4"), and gradually increasing loads led to less energy dissipation than constant loads.
3) Measurement of crack propagation using ultrasound found that larger aggregate sizes led to larger cracks under both constant and gradually increasing loads.
This document discusses friction, lubrication, and wear. It begins with an introduction to tribology, which is defined as the science of sliding surfaces in contact. The fundamentals of tribology are then explored, including elastic and plastic contact between surfaces. Different types of surface contact are described. Friction is also defined and the coefficients of static and dynamic friction are introduced. The document indicates that lubrication and wear will be discussed. It provides context about the authors and their related work in materials science before concluding with an overview of the chapter's contents.
This study investigated the impact of a nickel interlayer on the electrical resistance of a tin-tin interface under fretting loading conditions. Two coating systems were tested: bronze-tin and bronze-nickel-tin. Using variable displacement amplitude testing, the transition amplitude from partial slip to gross slip was determined. Constant displacement amplitude tests then evaluated the influence of the nickel interlayer on electrical endurance. The results showed that the nickel interlayer did not influence endurance in gross slip but eliminated copper diffusion through the tin coating, preventing copper oxide formation and extending the domain of partial slip. This increased the reliability of the electrical contact.
RajeshKumarSahu_118CR0682_Tribological Studies of Glass Ceramics.pptxRAJESHKUMARSAHU27
Glass ceramics are polycrystalline materials produced by controlled crystallization of inorganic glasses. They contain residual glass and crystalline phases ranging from 0.5-99.5%. The properties are controlled by a two-stage heat treatment process of nucleation and crystallization. Testing showed the glass ceramic had a friction coefficient of 0.55 in dry conditions but no stationary regime was reached in wet conditions due to surface dissolution. The glass ceramic had a hardness of 6.3 GPa, elastic modulus of 76.8 GPa, and low Archard coefficient indicating low wear rate making it suitable for tile applications.
This document provides a comprehensive literature review on buckling analysis of laminated composite plates. It discusses the effects of boundary conditions, lamination arrangements, and plate theories on buckling load prediction. Both exact and numerical methods have been used to analyze buckling of laminated plates, with higher-order shear deformation plate theories providing more accurate results than classical plate theory. The review covers past research on various plate theories and analytical and numerical techniques for buckling analysis of laminated composite plates.
EFFECT OF SURFACE ROUGHNESS ON CHARACTERISTICS OF SQUEEZE FILM BETWEEN POROUS...IAEME Publication
In investigation aims to analyse the effect of transverse surface roughness on the squeeze film performance between porous rectangular plates. The associated differential equation is stochastically averaged making use of stochastic averaging method of Christensen and Tonder for transverse surface roughness. The equation is solved with appropriate boundary conditions to obtain the pressure and consequentlythe load bearing. The graphical results suggest that the bearing suffers because of transverse surface roughness. However the situation is slightly better in the case of
negatively skew roughness. Further variance (-ve) makes the situation furtherimproved even if moderate values of porosity are involved
The document defines and explains delayed cracking (DC), which is a type of material failure observed in advanced high strength steels with tensile strength above 800 MPa. DC occurs after an incubation time with or without external loading and is caused by the interaction of stresses or residual stresses with hydrogen. A deep drawing test is used to reveal the susceptibility of materials to DC by observing crack formation after varying incubation periods. The document also defines and explains other material characterization techniques such as X-ray diffraction (XRD) and deformation mechanisms like transformation induced plasticity and twinning induced plasticity, as well as dynamic recrystallization during material processing.
This document discusses applying the NCHRP-1-28 resilient modulus model to characterize blended unbound granular materials in Sudan. An experimental testing program measured the resilient modulus of blended samples using dynamic triaxial tests. The NCHRP-1-28 model was used to predict resilient modulus values, which showed good agreement with measured values, being 8-10% lower, providing conservative estimates. The materials tested included natural gravels blended with sand and crushed stone to meet gradation specifications for base materials. Measured properties like density, CBR and gradation are reported for the blended samples.
Peculiarities of irrecoverable straining in stress-drop testIJERA Editor
The paper concerns with analytical description of the phenomena observed in stress drop tests, namely, negative increment in plastic and creep deformation due to the sudden decrease in the acting stresses while the net stress remains positive. The model is developed in terms of the synthetic theory of irrecoverable deformation which has been generalized by introducing interplay between the deformation properties of material in the direction of acting load and opposite to it.
1. Surface engineering aims to modify the properties of material surfaces to improve functionality, such as corrosion resistance, wear resistance, and friction reduction. Common surface engineering techniques include coatings, thermal treatments, and surface texturing.
2. Controlling friction through surface texturing has gained interest, as microscale dimples or grooves can reduce friction. However, the effects of texturing parameters like shape, depth, width, and orientation on friction are still being studied. Surface roughness parameters provide a way to characterize topography but may not fully describe surfaces.
3. The document discusses various surface roughness parameters defined by ISO standards and how they can characterize surface topography features relevant to friction, such as peaks, valleys
Laboratory Assessment of Energy Efficiency in Vibraotry Compaction of Granula...Garrett Osborne
This document describes a laboratory test method for assessing the energy efficiency of vibratory compaction of granular materials. The method tracks material density and energy consumption during compaction using a vibratory hammer. Density-energy curves are produced to evaluate both the maximum achievable density and the compactibility, or rate of density increase with energy. Testing of a granular concrete mix found that higher compactibility leads to more energy-efficient compaction by reaching the target density with less total energy. This approach can guide selection of optimal compaction variables like frequency to improve sustainability of earthworks construction.
Predicting a mathematical models of some mechanical properties of concrete ...Alexander Decker
This document summarizes a study that aimed to develop mathematical models to predict mechanical properties
of concrete from non-destructive testing methods. Specifically, the study examined properties of normal strength
concrete and high-strength concrete with compressive strengths ranging from 20-100 MPa using Schmidt
hammer and ultrasonic pulse velocity tests at ages of 7, 28, 56, and 90 days. The results showed good
correlations between compressive strength and both test methods. Relationships were also found between
modulus of elasticity, rebound number, and age of concrete. The document provides background on types of
concrete and non-destructive testing methods.
To Experimental Study of Comparison and Development of Design for Rigid Pavem...Agriculture Journal IJOEAR
Abstract— The development of design have been discussed adopted various types methods use. The Hadi and Arfiadi Method presents a formulation for the optimum rigid road pavement design by genetic algorithm, a new method. The Westergaard’s Method determines the stresses in the rigid concrete slab and also the pressure-deformation curve which depend upon the relative stiffness of the slab and the subgrade. Razouki and Al-Muhana also developed stress charts similar to Westergaard’s method. The paper reveals that the effects on the maximum bending tensile stress are quite significant due to the modulus of subgrade reaction, modulus of elasticity of concrete and slab The Maharaj and Gill method have performed axisymmetric finite element analysis by varying parameters, the thickness of pavement, pressure and elastic modulus of subgrade. The advantage of this method is that four types of design charts have been presented which other methods have note done. First type of design chart has been plotted between thickness of pavement and nodal deflections for various pressures for a particular elastic modulus of soil. Second type of design chart has been plotted between thickness of pavement and element stress for various pressures for a particular elastic modulus of soil. The third type of design chart has been plotted between thickness of pavement and nodal deflections for various elastic moduli of subgrade for a particular pressure. Each of the design charts has three parameters. For two known parameters, the third parameter can be obtained.
A composite material can be defined as a combination of two or more materials that
gives better properties than those of the individual components used alone. In contrast to
metallic alloys, each material retains its separate chemical, physical, and mechanical
properties. The two constituents are reinforcement and a matrix. The main advantages of
composite materials are their high strength and stiffness combined with low density when
compared to classical materials. Micromechanical approach is found to be more suitable for
the analysis of composite materials because it studies the volume proportions of the
constituents for the desired lamina stiffness and strength.
A new method is developed for determining material hardness from depth sensing indentation tests. Both loading and unloading data are used to calculate Meyer hardness values, which agree well with conventional optical measurements. While the new method characterizes hardness even for elastic materials, the conventional mean contact pressure definition differs significantly from hardness for elastic materials. A relationship is found between work during loading and unloading that allows hardness to be calculated using only load-depth data.
This document discusses the mechanical properties of viscoelastic materials. It covers topics like stress/strain behavior, creep, toughness, reinforcement, and modifiers. It explains how polymer chemistry, structures, and properties influence product performance. Key factors that determine a plastic's mechanical response are intermolecular forces, temperature, time under load, degree of crystallinity, and molecular weight. A plastic can behave as an elastic solid, viscoelastic solid, viscoelastic fluid, or viscous fluid depending on these factors. Tests like tensile testing, impact testing, and dynamic mechanical analysis are used to characterize mechanical properties.
This document presents a new model for describing the pressure dependence of elastic properties in uncemented sedimentary rocks. The model incorporates effects of sedimentary compaction and critical porosity on how porosity and density change with increasing pressure. It fits laboratory data on various rock samples well over a wide range of pressures. The new model provides an improved way to predict pressure-dependent rock properties and interpret seismic data compared to previous theoretical models.
Dynamic Relaxation (DR) method is presented for the analysis of geometrically linear laterally loaded, rectangular laminated plates. The analysis uses the Mindlin plate theory which accounts for transverse shear deformations. A computer program has been compiled. The convergence and accuracy of the DR solutions of isotropic, orthotropic, and laminated plates for elastic small deflection response are established by comparison with different exact and approximate solutions. The present Dynamic Relaxation (DR) method shows a good agreement with other analytical and numerical methods used in the verification scheme. It was found that: The convergence and accuracy of the DR solution were dependent on several factors which include boundary conditions, mesh size and type, fictitious densities, damping coefficients, time increment and applied load. Also, the DR small deflection program using uniform meshes can be employed in the analysis of different thicknesses for isotropic, orthotropic or laminated plates under uniform loads in a fairly good accuracy.
This document summarizes a study on using electro-physical probing methods to diagnose the state of boundary lubrication layers in sliding bearings. The study developed a 4-wiring circuit to indirectly analyze boundary lubrication layer thickness based on measuring contact resistance parameters under different loads. Calculations were performed to estimate contact point radius and relate resistance measurements to boundary lubrication layer thickness based on tunneling conductivity theory. Testing of the method found that decreasing contact resistance to the theoretical contact resistance level indicates destruction of the boundary lubrication layer, representing a "dry" metal contact.
Comparative Analysis of Equivalent Material based on MFIDr. Amarjeet Singh
Polymers of the same family show distinct behavior with each other and because of this, the end prediction after molding the part is very difficult. Simulations result does not always match the product. For close substitution in absence of exactly known material composition, the equivalent grade of the same MFI may be used. However, the MFI is a poor indicator of the rheological behavior to be comprehend for accurate simulation. This research analyzes the appropriate parameters for the rheology of polymers, in the same class that are appropriate.
Establishing relationship between cbr with different soil propertieseSAT Journals
Abstract
In the flexible pavements sub-grade is considered to be an ideal layer to resist wheel load and its CBR value is considered as the strength measuring parameter. Conducting CBR test is an expensive and time consuming test, moreover it is very difficult to mould the sample at a desired in-situ density in the laboratory. Further, if the available soil is of poor quality, suitable additives are mixed with soil and resulting strength of soil is assessed by CBR value which is cumbersome. To overcome these problems, the other methods such as regression based models (simple & multiple) are used in this study. The soil properties like liquid limit, plastic limit, plasticity index, optimum moisture content, maximum dry density and percentage fineness of the soil (passing 75micron sieve) are determined for the soil collected from different areas of Bagalkot district and the models are developed for correlating soaked CBR value.
Keywords: CBR, regression models, liquid limit, plastic limit, plasticity index, optimum moisture content and maximum dry density.
This document presents a simple phenomenological approach to modeling nanoindentation creep using conventional spring and dashpot elements. It describes how creep, which is the time-dependent increase in depth under a held load, can be modeled for a variety of materials using Maxwell and Voigt models. Equations are presented that relate the depth increase over time to the elastic modulus and viscosity of the material being tested. A method is described for fitting experimental nanoindentation data, including holding periods, to these equations to determine material properties while accounting for creep. The approach aims to provide an accessible way to analyze creep in nanoindentation that can be incorporated into computer programs.
International Journal of Engineering Research and DevelopmentIJERD Editor
1) The study investigated the effect of aggregate size on the energy dissipation of plain concrete members subjected to static cyclic loading.
2) Testing found that smaller aggregate size (3/8") resulted in less energy dissipation compared to larger sizes (1/2", 3/4"), and gradually increasing loads led to less energy dissipation than constant loads.
3) Measurement of crack propagation using ultrasound found that larger aggregate sizes led to larger cracks under both constant and gradually increasing loads.
This document discusses friction, lubrication, and wear. It begins with an introduction to tribology, which is defined as the science of sliding surfaces in contact. The fundamentals of tribology are then explored, including elastic and plastic contact between surfaces. Different types of surface contact are described. Friction is also defined and the coefficients of static and dynamic friction are introduced. The document indicates that lubrication and wear will be discussed. It provides context about the authors and their related work in materials science before concluding with an overview of the chapter's contents.
This study investigated the impact of a nickel interlayer on the electrical resistance of a tin-tin interface under fretting loading conditions. Two coating systems were tested: bronze-tin and bronze-nickel-tin. Using variable displacement amplitude testing, the transition amplitude from partial slip to gross slip was determined. Constant displacement amplitude tests then evaluated the influence of the nickel interlayer on electrical endurance. The results showed that the nickel interlayer did not influence endurance in gross slip but eliminated copper diffusion through the tin coating, preventing copper oxide formation and extending the domain of partial slip. This increased the reliability of the electrical contact.
This document discusses a study that evaluated the effect of indentation size on the microhardness values of two viscoelastic dental materials (a resin composite and resin modified glass ionomer cement) under different loads and holding times. Vickers and Knoop microhardness tests were used to assess the materials at loads of 100, 200, and 300g and times of 10, 20, and 30 seconds. The results showed that microhardness values for both materials were significantly affected by the load for Vickers hardness tests. For Knoop hardness tests, only the composite showed significant load-dependence while the resin modified glass ionomer cement did not. The optimal load and time to determine microhardness could not be conclusively determined for either
Finite Element Analysis of honeycomb using AbaqusUdayan Ghosh
Prepared 3D CAD model of honeycomb in SolidWorks; studied structural behavior for static and dynamic loading
Performed mesh refinement, verification, validation and error analysis for the FEA
The document describes experiments conducted to determine the relative density of glucose and ethylene glycol using a pycnometer, and the dynamic and kinematic viscosity of glycerin using a falling sphere viscometer. The specific gravity of glucose and ethylene glycol were calculated from measurements of the pycnometer weight with and without the samples. Data from the viscometer test including steel ball mass, elapsed time, and diameter were used to calculate the dynamic and kinematic viscosity of glycerin. A graph of observed velocity versus the ratio of steel ball diameter to viscometer diameter showed consistency in the viscometer data.
20. Evaluation of static and dynamic properties of sand–fines mixtures.pdfPinakRay2
This document evaluates the static and dynamic properties of sand-fines mixtures through state and equivalent state parameters. Laboratory tests were conducted on sand-fines mixtures with fines contents ranging from 0% to 60% under drained and undrained conditions. Key findings include:
1) A unique critical state line was obtained for each fines content from the triaxial tests.
2) Normalized peak undrained shear stress, cyclic resistance ratio, and compression index correlated well with the state parameter Ψ and equivalent state parameter Ψ*.
3) As the state parameter increased, normalized peak undrained shear stress and cyclic resistance ratio decreased while compression index increased.
12-2-Publication-Experimental Analysis of Explosive FormingSaeed Jabalamelian
This study numerically simulates and experimentally tests the explosive hydroforming process used to form torispherical heads made of aluminum alloy AA5083. Finite element models using LS-DYNA software were developed to simulate the process, applying the Johnson-Cook and Modified Zerilli-Armstrong constitutive models. The models were verified against experimental tests. The simulation captured most material behaviors under different stress states but did not fully describe the transient zone between tension and compression. The predicted width of the transient rim was smaller than seen experimentally. Overall the blast loading simulation showed good agreement with Cole's relation for underwater detonation of small charges, with 95% accuracy.
Viscoelastic response of polymeric solids in sliding contactspadmanabhankrishnan4
Abstract: The viscoelastic response of polymeric solids to sliding contact conditions
is observed and analyzed with respect to the sliding speed, material composition,
and geometry. It was discovered that polymeric solids produced their own distinct
viscoelastic signatures that cause resonance at certain sliding speeds which can be
explained with resonance conditions for electromagnetic waves. The observed viscolelastic phenomenon is characterized with respect to the relaxation and recovery
times for rigid polymeric solids. It is confirmatory as a demonstration of proof of
existence of viscoelasticity and self-organization in these materials under sliding contact conditions. Viscoelastic observations are also made on the aged specimens in
sliding contact.
Examples of Mechanical Property EvaluationsJacob Feste
The document summarizes an experiment that measured and compared the viscoelastic properties of four polymers: low density polyethylene (LDPE), high density polyethylene (HDPE), Neoprene, and Red Silicone. Creep and hysteresis tests were performed on LDPE and Neoprene samples, while stress relaxation tests were conducted on HDPE and Red Silicone samples using an Instron machine. The results showed that LDPE lost significantly more average energy (38,653 N/m2) than Neoprene (3,261.5 N/m2) in the hysteresis tests, and HDPE exhibited a larger change in stress over time compared to Red Silicone in the stress relaxation tests.
This document summarizes a study estimating geo-mechanical properties of reservoir rocks from well log data. The study presents a method to predict shear wave velocity from compressional wave velocity, porosity, and shale content when direct shear wave measurements are unavailable. Elastic properties including Poisson's ratio, shear modulus, bulk modulus, and Young's modulus are then calculated. These properties allow evaluation of formation strength and prediction of safe production rates without sand production. The results show shear and compressional wave velocities are linearly related. Calculated combined modulus of strength and shear modulus to compressibility ratio values indicate the formations can generally be produced safely below an optimum flow rate without significant sand production risks.
Estimating geo mechanical strength of reservoir rocks from well logs for safe...Alexander Decker
This document summarizes a study that estimated geo-mechanical properties of reservoir rocks from well log data in order to determine safety limits for sand-free hydrocarbon production. The study used well logs to predict shear wave velocity and then calculate elastic moduli, which can indicate a formation's mechanical strength. The results showed that the combined modulus of strength and shear modulus to compressibility ratio for the formations were relatively low, suggesting sand production should not occur below certain flow rates. This information on a formation's mechanical properties can help minimize risks during hydrocarbon exploration and production.
1. The document studies the effect of chemical solutions on the mechanical and thermal properties of an epoxy resin composite reinforced with 1% and 3% nano aluminum oxide powder.
2. Test results showed that reinforcing the epoxy increased its flexural strength, Young's modulus, surface hardness, and thermal conductivity.
3. Immersing the composites in acid and base solutions for 9 weeks decreased the mechanical properties over time due to material degradation, while increasing the thermal conductivity. The acid solution had a greater impact than the base.
This summary provides an overview of Jimmy Pan's summer research project at Vanderbilt University's Multiscale Computational Mechanics Laboratory:
- The project involved modeling acoustic bandgaps in layered composite structures using high order homogenization equations to establish relationships between microstructure, material properties, and energy dissipation under dynamic loads.
- Jimmy worked to establish a function to determine the parameter ν, which optimizes the agreement between the experimental model and analytical Floquet-Bloch reference model for a range of material combinations.
- Through generating data mapping the best-fitting ν values to impedance and wave velocity contrasts between materials, denoted as ẑ and ĉ, Jimmy aimed to express ν as
1) The document investigates the effect of low-velocity impact and fatigue loading on woven glass fiber/epoxy composite laminates of different thicknesses (2mm and 4mm).
2) Specimens were subjected to low-velocity impact testing at different energy levels. Impacted specimens and non-impacted specimens were then subjected to tension-tension fatigue testing.
3) Results showed that impact velocity significantly influenced the fatigue life of composite laminates. The 2mm thick impacted laminates saw a drastic reduction in fatigue life compared to the 4mm laminates.
Testing of Already Existing and Developing New Compaction Equations during C...IJMER
Powder Metallurgy (P/M) processing of materials to produce conventional P/M parts
involve the compaction of the pre-determined mass of individual elemental, mixed elemental metal
powders or alloy powders and or composite powders into green compacts and sintering them under
reducing atmosphere and or under other protective coatings, thus, after sintering producing
products after mild machining operations. Therefore, compaction represents one of the most
important stages in the production of engineering components using the P/M route. However, the
physical properties such as density and the stress distribution in the green compacts are determined
not only by the properties of the constituents of the powder or the powder blend, but, also by the
pressing modes and schedules. Thus, the present investigation pertains to generate experimental
data on the compaction behaviour of Fe-1.05% graphitesystems with two different iron particle size
ranges and two different powder masses in order to highlight the various aspects of compaction and
also testing out the already existing compaction equations and search for the new ones. Powder
blends of two different iron powder particle size ranges, namely, -106+53µm and -150+106µm
respectively were blended with the required amount of graphite powder of 3 – 5 µm sizes for a
period of 32 hours. Compaction studies have been carried out for two different amounts of both
powder blends. The two amounts taken were 65g and 85g respectively. However, the main attempt
was made to record the load and the corresponding heights and the top punch displacements for
every two tons (0.02MN) of load which was applied in the steps of 0.02MN. Various equations for
compaction were attempted empirically and the already existing ones were also tested. Critical
analysis of the experimental data and the calculated parameters have resulted into several
compaction equations which were arrived at empirically. The regression coefficient ‘R2
’ in each
case where compactions equations were empirically obtained was in very much close proximity to
unity. However, it has been also confirmed that the data of the present investigation were well
taken up by the earlier compactions equations, thus, validating them comprehensively.
Numerical simulation of laterally loaded pileDr. Naveen BP
This document presents a finite element model simulation of a lateral load test on a 1m diameter bored pile embedded in residual soils. The pile and soil were modeled in PLAXIS 2D, with the soil represented by a Mohr-Coulomb model and the pile as a beam element. The model results showed good agreement with load-displacement curves from the field test. However, the field test was unable to apply loads high enough to reach design code displacement limits due to limitations of test equipment for large piles in residual soils. The numerical model can simulate larger displacements to evaluate pile behavior under higher loads.
1) The document discusses the behavior of materials and metals when subjected to compressive and tensile loads within their elastic ranges. It describes testing plain cement concrete cubes and metallic rods/wires in compression and tensile testing machines.
2) Key findings include that stress and strain increase proportionally within materials' elastic range, and inversely beyond it. The document also introduces a "Sultan Jain modulus" to quantify the relationship between stress, strain, and density.
3) Advantages of considering density in strength calculations are outlined. Procedures for gradually stretching thick wires into thin wires within the elastic range using a die are also described.
New workA)Transfer It Please respond to the following· U.docxcurwenmichaela
New work
A)
"Transfer It" Please respond to the following:
· Using 140 characters or less (the length of a Tweet), summarize the importance of this class to someone unfamiliar with the concepts.
· Discuss ways you can apply what you learned in this course to your current or future position.
Note: this is the class of INTRODUCTION OF COMPUTER INFO SYSTEM
ABSTRACT
The report describe the results obtained from a tensile test. This was in determination of the ultimate tensile strength of both metals and polymeric materials. It is common knowledge that materials have certain unique properties but assigning the exact values to them requires a well outlined laboratory procedure. The materials under testing were; steel, aluminum, high density polyethylene, and low density polyethylene. The results obtained were analyzed and presented in graphical form.
INTRODUCTION
The Ultimate Tensile strength of a material is the maximum amount of stress that a given material can tolerate when pulling forces are applied at both ends, without failing. Ultimate Tensile strength is differentiated from compressive strength in that the former is acted upon by forces that pull a material outwards on both sides while the latter is acted upon by forces that push a material inwards. (David, 2008) Tensile strength is determined by using a cylindrical sample of known length and cross sectional area and subjecting it to tensile forces in a tensile machine. Most commonly used tensile machines include: lab master z-direction tensile tester and universal tester. (David, 2008) When the tests are carried out, the stress-strain relationships is easily determined hence making it easy to deduce the ultimate tensile strength of the material specimen and its young’s modulus.
When designing for rigid structures, the properties of various construction materials need to be determined. (David, 2008)The reason being materials are subject to external forces when used in construction of structures. Different materials have different properties due to differences in their molecular structure. This fact is evident in the case of metals and polymeric samples which exhibit different physical and chemical properties due to variances in molecular structure and in extension atomic composition. This makes them react differently to when subjected to external forces. Metal are generally stronger than polymers hence used in area which experience heavy loading in a structure. In order for one to find the most suitable material for a particular project, material property needs to be known, with the most natural property being tensile strength.
Steel and aluminum are the most commonly used metals in construction projects. They have both high electrical and thermal conductivity, relatively high densities, high melting points, and both high ultimate and yield strength. (Gordon, 1976)Steel is mostly used together with concrete to form rigid structure such as buildings and dams. Aluminum is mostly us ...
This document discusses mechanical properties of matter such as density, elasticity, and fluid pressure. It defines key terms like density, specific gravity, stress, strain, and Hooke's law. Hooke's law states that the deformation of a material is proportional to the force applied. Young's modulus is introduced as a measure of a material's elasticity, relating stress to strain. Examples are worked through to demonstrate calculating density, specific gravity, stress, strain, and deformation based on given values and materials.
Similar to Annals of Materials Science & Engineering (20)
Austin Journal of Robotics & Automation is an international scholarly, peer review, Open Access journal, initiated with an aim to promote the research in Robotics & Automation, which deals with design, construction, operation, and application of robots.
Austin Journal of Robotics & Automation is a comprehensive Open Access peer reviewed scientific journal that covers multidisciplinary fields. We provide limitless access towards accessing our literature hub with colossal range of articles. The journal aims to publish high quality varied article types such as Research, Review, Short Communications, Case Reports, Perspectives (Editorials).
Austin Journal of Robotics & Automation supports the scientific modernization and enrichment in Robotics & Automation research community by magnifying access to peer reviewed scientific literary works. Austin Publishing Group also brings universally peer reviewed member journals under one roof thereby promoting knowledge sharing, collaborative and promotion of multidisciplinary technology.
Austin Journal of Multiple Sclerosis & Neuroimmunology is an open access, peer review Journal publishing original research & review articles on aetiology, epidemiology, and pathogenesis of inflammatory demyelinating diseases of the central nervous system. Austin Journal of Multiple Sclerosis & Neuroimmunology is aimed to provide a strong platform for challenging cases that includes but not excludes the damage of insulating covers of both central nervous system and spine. It is a grounding platform for all neurologists, neuroimmunologists, neurovirologists, researchers, medical doctors, health professionals, scientists, and scholars to publish their research work & update the latest research information.
Topics include but not limited to Clinical Neurology, Biomarkers, Glial, Myelin Chemistry, Neuroimaging, Neuropathology, Neuroepidemiology, Therapeutics, Genetics/Transcriptomics, Experimental Models, Pathobiology, Neuroimmunology, Neuropsychology, Neurorehabilitation, Pathobiology of the Brain, Psychology, Measurement Scales, Teaching, and Neuroethics.
Austin Journal of Multiple Sclerosis & Neuroimmunology supports the scientific transformation and fortification in Medical and Clinical research community by magnifying access to peer reviewed scientific literary works. Austin also brings universally peer reviewed member journals under one roof thereby promoting knowledge sharing, collaborative and promotion of multidisciplinary science.
Austin Leukemia is an open access, peer reviewed, scholarly journal dedicated to publish articles covering all areas of Leukemia.
The journal aims to promote research communications and provide a forum for doctors, researchers, physicians and healthcare professionals to find most recent advances in all areas of Leukemia. Austin Leukemia accepts original research articles, reviews, mini reviews, case reports and rapid communication covering all aspects of Leukemia.
Austin Leukemia strongly supports the scientific up gradation and fortification in related scientific research community by enhancing access to peer reviewed scientific literary works. Austin Publishing Group brings universally peer reviewed journals under one roof thereby promoting knowledge sharing, mutual promotion of multidisciplinary science.
Autism impacts normal brain development in areas of social interaction and communication. People with autism may exhibit repetitive behaviors, unusual responses to people, attachment to objects, and resistance to change in routine. The main types of autism are autistic disorder, Asperger's disorder, pervasive developmental disorder, Rett's disorder, and childhood disintegrative disorder, which are distinguished based on levels of impairment and when symptoms begin. While there is no definitive medical test, autism is diagnosed by a team using interviews, observations, and checklists to evaluate social skills, communication, and restricted or repetitive behaviors.
Austin Journal of Asthma: Open Access is an open access, peer reviewed, scholarly journal dedicated to publish articles covering all areas of Asthma.
The journal aims to promote latest information and provide a forum for doctors, researchers, physicians, and healthcare professionals to find most recent advances in the areas of Asthma. Austin Journal of Asthma: Open Access accepts research articles, reviews, mini reviews, case reports and rapid communication covering all aspects of Asthma.
Austin Journal of Asthma: Open Access strongly supports the scientific up gradation and fortification in related scientific research community by enhancing access to peer reviewed scientific literary works. Austin Publishing Group also brings universally peer reviewed journals under one roof thereby promoting knowledge sharing.
Austin Journal of Anesthesia and Analgesia is an open access, peer reviewed, scholarly journal dedicated to publish articles in all areas of anesthesiology and pain management.
The aim of the journal is to provide a forum for anesthesiologists, researchers, physicians, and other health professionals to find most recent advances in the areas of anesthesiology. Austin Journal of Anesthesia and Analgesia accepts original research articles, review articles, case reports and rapid communication on all the aspects of anesthesiology and pain management.
Austin Journal of Anesthesia and Analgesia strongly supports the scientific upgradation and fortification in related scientific research community by enhancing access to peer reviewed scientific literary works. Austin Publishing Group also brings universally peer reviewed journals under one roof thereby promoting knowledge sharing, mutual promotion of multidisciplinary science.
Austin Journal of Accounting, Audit and Finance Management is a peer reviewed open access journal in publishes manuscripts from all the areas of accounting, accountancy, finance, auditing.
Austin Journal of Accounting, Audit and Finance Management Original Articles, Review, Discussion, Editorials, Letter, type of manuscripts from all the areas of the accounting, accountancy, finance, auditing.
Austin Virology and Retrovirology is an international scholarly peer reviewed Open Access journal, aims to promote the research in the field of Virology.
Austin Virology and Retrovirology is a comprehensive Open Access peer reviewed scientific Journal that covers multidisciplinary fields. We provide limitless access towards accessing our literature hub with colossal range of articles. The journal aims to publish high quality varied article types such as Research, Review, Case Reports, Short Communications, Perspectives (Editorials), Clinical Images
Austin Virology and Retrovirology supports the scientific modernization and enrichment in virology research community by magnifying access to peer reviewed scientific literary works. Austin also brings universally peer reviewed member journals under one roof thereby promoting knowledge sharing, collaborative and promotion of multidisciplinary science.
Austin Journal of Urology is an open access, peer reviewed, scholarly journal dedicated to publish articles in all areas of Urology.
The aim of the journal is to provide a forum for urologists, nephrologists, research scholars, physicians, and other healthcare professionals to find most recent advances in the field of Urology.
Austin Journal of Urology accepts original research articles, review articles, case reports and short communication on all the aspects of Urology and relevant basic science issues.
Annals of Thyroid Research is a peer-reviewed, open access journal published by Austin Publishers. It provides easy access to high quality Manuscripts in all related aspects of thyroid hormones and thyroid diseases and their interaction with the cardiovascular system, pulmonary system, gastroenteron system, metabolic and nervous systems. The journal also focuses upon all the thyroid disease symptoms and treatments, including hyperthyroid and hypothyroid, plus a range of other thyroid problems including thyroid cancer.
Austin Publishing Group is a successful host of more than hundred peer reviewed, open access journals in various fields of science and medicine with intent to bridge the gap between academia and research access.
Annals of Thyroid Research accepts original research articles, review articles, case reports, mini reviews, rapid communication, opinions and editorials on all related aspects of all related aspects of thyroid hormones and thyroid diseases.
Austin Journal of Robotics & Automation is an international scholarly, peer review, Open Access journal, initiated with an aim to promote the research in Robotics & Automation, which deals with design, construction, operation, and application of robots.
Austin Journal of Robotics & Automation is a comprehensive Open Access peer reviewed scientific journal that covers multidisciplinary fields. We provide limitless access towards accessing our literature hub with colossal range of articles. The journal aims to publish high quality varied article types such as Research, Review, Short Communications, Case Reports, Perspectives (Editorials).
Austin Journal of Robotics & Automation supports the scientific modernization and enrichment in Robotics & Automation research community by magnifying access to peer reviewed scientific literary works. Austin Publishing Group also brings universally peer reviewed member journals under one roof thereby promoting knowledge sharing, collaborative and promotion of multidisciplinary technology.
Austin Journal of Orthopedics & Rheumatology is an open access, peer reviewed, scholarly journal dedicated to publish articles in all areas of Orthopedics.
The aim of the journal is to provide a forum for orthopedicians, researchers, physicians, and other health professionals to find most recent advances in the areas of Orthopedics.
Austin Journal of Orthopedics & Rheumatology accepts original research articles, review articles, case reports and rapid communication on all the aspects of Orthopedics and its related areas.
Austin Pediatrics is an open access, peer reviewed, scholarly journal committed to publish articles in all areas of science and practice of Pediatrics.
The aspire of the journal is to present a platform for scientists and academicians all over the world to encourage, distribute, and discuss various new issues and developments in different areas of Pediatrics and to promote responsible and balanced debate on controversial issues that influence child health, including non-clinical areas such as ethics, law, surroundings and economics.
Austin Pediatrics accepts innovative research articles, review articles, case reports and rapid communication on all the aspects of Pediatrics.
Austin Pediatrics is an open access, peer reviewed, scholarly journal committed to publish articles in all areas of science and practice of Pediatrics.
Austin Otolaryngology is an open access, peer review journal publishing original research & review articles in all the fields of Otolaryngology. Otolaryngology deals with the study of ear, nose and throat. Austin Otolaryngology provides a new platform for students to publish their research work & update the latest research information in Otolaryngology.
Austin Otolaryngology is a comprehensive Open Access peer reviewed scientific Journal that covers multidisciplinary fields. We provide limitless access towards accessing our literature hub with colossal range of articles. The journal aims to publish high quality varied article types such as Research, Review, Short Communications, Case Reports, Perspectives (Editorials), Clinical Images.
Austin Otolaryngology supports the scientific modernization and enrichment in Otolaryngology research community by magnifying access to peer reviewed scientific literary works. Austin Publishing Group also brings universally peer reviewed member journals under one roof thereby promoting knowledge sharing, collaborative and promotion of multidisciplinary science.
Clinics in Oncology Research is an open access, peer reviewed, scholarly journal dedicated to publish articles covering all areas of oncology.
The journal aims to promote latest information and provide a forum for oncologists, doctors, researchers, physicians, and healthcare professionals to find most recent advances in the areas of oncology. Clinics in Oncology Research accepts research articles, reviews, mini reviews, case reports and rapid communication covering all aspects of oncology.
Clinics in Oncology Research strongly support the scientific up gradation and fortification in related scientific research community by enhancing access to peer reviewed scientific literary works. Austin Publishing Group also brings universally peer reviewed journals under one roof thereby promoting knowledge sharing.
Austin Journal of Obesity & Metabolic Syndrome is an international scholarly peer reviewed Open Access journal, aims to promote the research in all the related fields of Metabolic Syndrome.
Austin Journal of Obesity & Metabolic Syndrome is a comprehensive Open Access peer reviewed scientific Journal that covers multidisciplinary fields. We provide limitless access towards accessing our literature hub with colossal range of articles. The journal aims to publish high quality varied article types such as Research, Review, Short Communications, Case Reports, Perspectives (Editorials), Clinical Images.
Austin Journal of Obesity & Metabolic Syndrome supports the scientific modernization and enrichment in Metabolic Syndromes research community by magnifying access to peer reviewed scientific literary works. Austin Publishing Group also brings universally peer reviewed member journals under one roof thereby promoting knowledge sharing, collaborative and promotion of multidisciplinary science.
Austin Journal of Nutrition and Food sciences is an open access, peer reviewed, scholarly journal dedicated to publish articles in all areas of nutrition and food sciences
The aim of the journal is to provide a forum for dietitians, researchers, physicians, and other health professionals to find most recent advances in the areas of clinical nutrition and nutritional disorders.
Austin Journal of Nutrition and Food sciences accepts original research articles, review articles, case reports and rapid communication on all the aspects of internal medicine.
Austin Journal of Clinical Neurology is an open access, peer reviewed, scholarly journal dedicated to publish articles in all areas of neurology, neurophysiology and stroke.
The aim of the journal is to provide a forum for neurologists, researchers, physicians, and other health professionals to find most recent advances in the areas of clinical and experimental neurology. Austin Journal of Clinical Neurology accepts original research articles, review articles, case reports, clinical images and rapid communication on all the aspects of clinical neurology and nervous system diseases.
Austin Journal of Clinical Neurology strongly supports the scientific upgradation and fortification in related scientific research community by enhancing access to peer reviewed scientific literary works. Austin Publishing Group also brings universally peer reviewed journals under one roof thereby promoting knowledge sharing, mutual promotion of multidisciplinary science.
Austin Journal of Clinical Neurology is an open access, peer reviewed, scholarly journal dedicated to publish articles in all areas of neurology, neurophysiology and stroke.
Austin Journal of Musculoskeletal Disorders is a peer-reviewed, open access journal published by Austin Publishers. It provides easy access to high quality Manuscripts in all related aspects of diseases and disorders that may adversely affect the function and overall effectiveness of the musculoskeletal system. The Journal focuses upon all the related aspects of musculoskeletal system disorders and the new advancements in the related treatments including Complex issues and injuries involving the musculoskeletal system and surgeries.
Austin Publishing Group is a successful host of more than hundred peer reviewed, open access journals in various fields of science and technology with intent to bridge the gap between academia and research access.
Austin Journal of Musculoskeletal Disorders accepts original research articles, review articles, case reports, mini reviews, rapid communication, opinions and editorials on all related aspects of diseases and disorders that may adversely affect the function and overall effectiveness of the musculoskeletal system.
Austin Hypertension is an open access, peer reviewed, scholarly journal dedicated to publish articles covering all areas of Hypertension.
The journal aims to promote research communications and provide a forum for doctors, researchers, physicians and healthcare professionals to find most recent advances in all areas of Hypertension. Austin Hypertension accepts original research articles, reviews, mini reviews, case reports and rapid communication covering all aspects of hypertension.
Austin Hypertension strongly supports the scientific up gradation and fortification in related scientific research community by enhancing access to peer reviewed scientific literary works. Austin Publishing Group also brings universally peer reviewed journals under one roof thereby promoting knowledge sharing, mutual promotion of multidisciplinary science.
Ensure the highest quality care for your patients with Cardiac Registry Support's cancer registry services. We support accreditation efforts and quality improvement initiatives, allowing you to benchmark performance and demonstrate adherence to best practices. Confidence starts with data. Partner with Cardiac Registry Support. For more details visit https://cardiacregistrysupport.com/cancer-registry-services/
India Medical Devices Market: Size, Share, and In-Depth Competitive Analysis ...Kumar Satyam
According to TechSci Research report, “India Medical Devices Market Industry Size, Share, Trends, Competition, Opportunity and Forecast, 2019-2029,” the India Medical Devices Market was valued at USD 15.35 billion in 2023 and is anticipated to witness impressive growth in the forecast period, with a Compound Annual Growth Rate (CAGR) of 5.35% through 2029. This growth is driven by various factors, including strategic collaborations and partnerships among leading companies, a growing population, and the increasing demand for advanced healthcare solutions.
Recent Trends
Strategic Collaborations and Partnerships
One of the most significant trends driving the India Medical Devices Market is the increasing number of collaborations and partnerships among leading companies. These alliances aim to merge the expertise of individual companies to strengthen their market position and enhance their product offerings. For instance, partnerships between local manufacturers and international companies bring advanced technologies and manufacturing techniques to the Indian market, fostering innovation and improving product quality.
Browse over XX market data Figures and spread through XX Pages and an in-depth TOC on " India Medical Devices Market.” - https://www.techsciresearch.com/report/india-medical-devices-market/8161.html
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.
More@: https://tinyurl.com/2shrryhx
More@: https://tinyurl.com/5n8h3wp8
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.
2024 Media Preferences of Older Adults: Consumer Survey and Marketing Implica...Media Logic
When it comes to creating marketing strategies that target older adults, it is crucial to have insight into their media habits and preferences. Understanding how older adults consume and use media is key to creating acquisition and retention strategies. We recently conducted our seventh annual survey to gain insight into the media preferences of older adults in 2024. Here are the survey responses and marketing implications that stood out to us.
The Ultimate Guide in Setting Up Market Research System in Health-TechGokul Rangarajan
How to effectively start market research in the health tech industry by defining objectives, crafting problem statements, selecting methods, identifying data collection sources, and setting clear timelines. This guide covers all the preliminary steps needed to lay a strong foundation for your research.
"Market Research it too text-booky, I am in the market for a decade, I am living research book" this is what the founder I met on the event claimed, few of my colleagues rolled their eyes. Its true that one cannot over look the real life experience, but one cannot out beat structured gold mine of market research.
Many 0 to 1 startup founders often overlook market research, but this critical step can make or break a venture, especially in health tech.
But Why do they skip it?
Limited resources—time, money, and manpower—are common culprits.
"In fact, a survey by CB Insights found that 42% of startups fail due to no market need, which is like building a spaceship to Mars only to realise you forgot the fuel."
Sudharsan Srinivasan
Operational Partner Pitchworks VC Studio
Overconfidence in their product’s success leads founders to assume it will naturally find its market, especially in health tech where patient needs, entire system issues and regulatory requirements are as complex as trying to perform brain surgery with a butter knife. Additionally, the pressure to launch quickly and the belief in their own intuition further contribute to this oversight. Yet, thorough market research in health tech could be the key to transforming a startup's vision into a life-saving reality, instead of a medical mishap waiting to happen.
Example of Market Research working
Innovaccer, founded by Abhinav Shashank in 2014, focuses on improving healthcare delivery through data-driven insights and interoperability solutions. Before launching their platform, Innovaccer conducted extensive market research to understand the challenges faced by healthcare organizations and the potential for innovation in healthcare IT.
Identifying Pain Points: Innovaccer surveyed healthcare providers to understand their difficulties with data integration, care coordination, and patient engagement. They found widespread frustration with siloed systems and inefficient workflows.
Competitive Analysis: Analyzed competitors offering similar solutions in healthcare analytics and interoperability. Identified gaps in comprehensive data aggregation, real-time analytics, and actionable insights.
Regulatory Compliance: Ensured their platform complied with HIPAA and other healthcare data privacy regulations. This compliance was crucial to gaining trust from healthcare providers wary of data security issues.
Customer Validation: Conducted pilot programs with several healthcare organizations to validate the platform's effectiveness in improving care outcomes and operational efficiency. Gathered feedback to refine features and user interface.
Emotional and Behavioural Problems in Children - Counselling and Family Thera...PsychoTech Services
A proprietary approach developed by bringing together the best of learning theories from Psychology, design principles from the world of visualization, and pedagogical methods from over a decade of training experience, that enables you to: Learn better, faster!
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.
TEST BANK FOR Health Assessment in Nursing 7th Edition by Weber Chapters 1 - ...rightmanforbloodline
TEST BANK FOR Health Assessment in Nursing 7th Edition by Weber Chapters 1 - 34.
TEST BANK FOR Health Assessment in Nursing 7th Edition by Weber Chapters 1 - 34.
TEST BANK FOR Health Assessment in Nursing 7th Edition by Weber Chapters 1 - 34.
The facial nerve, also known as cranial nerve VII, is one of the 12 cranial nerves originating from the brain. It's a mixed nerve, meaning it contains both sensory and motor fibres, and it plays a crucial role in controlling various facial muscles, as well as conveying sensory information from the taste buds on the anterior two-thirds of the tongue.
English Drug and Alcohol Commissioners June 2024.pptxMatSouthwell1
Presentation made by Mat Southwell to the Harm Reduction Working Group of the English Drug and Alcohol Commissioners. Discuss stimulants, OAMT, NSP coverage and community-led approach to DCRs. Focussing on active drug user perspectives and interests
CHAPTER 1 SEMESTER V COMMUNICATION TECHNIQUES FOR CHILDREN.pdfSachin Sharma
Here are some key objectives of communication with children:
Build Trust and Security:
Establish a safe and supportive environment where children feel comfortable expressing themselves.
Encourage Expression:
Enable children to articulate their thoughts, feelings, and experiences.
Promote Emotional Understanding:
Help children identify and understand their own emotions and the emotions of others.
Enhance Listening Skills:
Develop children’s ability to listen attentively and respond appropriately.
Foster Positive Relationships:
Strengthen the bond between children and caregivers, peers, and other adults.
Support Learning and Development:
Aid cognitive and language development through engaging and meaningful conversations.
Teach Social Skills:
Encourage polite, respectful, and empathetic interactions with others.
Resolve Conflicts:
Provide tools and guidance for children to handle disagreements constructively.
Encourage Independence:
Support children in making decisions and solving problems on their own.
Provide Reassurance and Comfort:
Offer comfort and understanding during times of distress or uncertainty.
Reinforce Positive Behavior:
Acknowledge and encourage positive actions and behaviors.
Guide and Educate:
Offer clear instructions and explanations to help children understand expectations and learn new concepts.
By focusing on these objectives, communication with children can be both effective and nurturing, supporting their overall growth and well-being.
Enhancing Hip and Knee Arthroplasty Precision with Preoperative CT and MRI Im...Pristyn Care Reviews
Precision becomes a byword, most especially in such procedures as hip and knee arthroplasty. The success of these surgeries is not just dependent on the skill and experience of the surgeons but is extremely dependent on preoperative planning. Recognizing this important need, Pristyn Care commits itself to the integration of advanced imaging technologies like CT (Computed Tomography) and MRI (Magnetic Resonance Imaging) into the surgical planning process.
Fit to Fly PCR Covid Testing at our Clinic Near YouNX Healthcare
A Fit-to-Fly PCR Test is a crucial service for travelers needing to meet the entry requirements of various countries or airlines. This test involves a polymerase chain reaction (PCR) test for COVID-19, which is considered the gold standard for detecting active infections. At our travel clinic in Leeds, we offer fast and reliable Fit to Fly PCR testing, providing you with an official certificate verifying your negative COVID-19 status. Our process is designed for convenience and accuracy, with quick turnaround times to ensure you receive your results and certificate in time for your departure. Trust our professional and experienced medical team to help you travel safely and compliantly, giving you peace of mind for your journey.www.nxhealthcare.co.uk
2. Ann Materials Sci Eng 2(2): id1022 (2015) - Page - 02
Bandyopadhyay S Austin Publishing Group
Submit your Manuscript | www.austinpublishinggroup.com
such as maximum load, holding time and loading rate cause a change
in H and Er
of metals as well as polymers [13,15,17,18]. Metals and
ductilepolymershavehighstrainandstrainrate-dependentproperties
and show substantially different behaviours when the indentations
are produced under differing contact conditions. So far, in literature,
effect of test parameters on properties of metals and polymers have
been studied separately under different conditions, hence correlating
the response of these two different materials is usually not possible.
Therefore, a new study was conducted in this work under same
experimental conditions to investigate and compare the response of
dissimilar materials (metals and polymers) in relation to properties
such as H and Er
on changing nano-indentation test parameters.
Materials and Experiments
Three different materials, namely, copper (Cu), low density
polyethylene (LDPE) and high density polyethylene reinforced with
flyash(HDPE+FA),weretestedonHysitronTI900nano-indentation
in four different profiles as shown in Figure 2. All samples were
polished using grade 1200 metallographic polishing paper, and each
sample was tested under nano-indentation at 10 different locations
under each set of conditions and average values were noted. Figure
2A shows a comparison at constant contact parameters whereas Figs.
2B, C and D show a comparison at varying maximum load, loading
rate, and holding time respectively while keeping other parameters
constant.
After loading-unloading cycle, test data was recorded to calculate
H, Er
and H/Er
2
using equations 1 [19], 2 [19] and 3 [20] respectively:
max
Equation 1
P
H
A
=
Equation 2
2
r
S
E
A
π
β
=
max
2 2
4
Equation 3
r
PH
E Sπ
=
In equations 1, 2 and 3, Pmax
is maximum load and S is stiffness,
measured as a slope of initial unloading curve which is normally
considered as a perfect elastic event [21]. A is the contact area of the
indentation and β is the correction factor for the indenter shape. For
Berkovich indenter A=24. 5hc
2
[22] and β = 1.07 [3].
Analysis of Experimental Results and
Discussion
Part A): Basic comparison
The three materials were subjected to preliminary nano-
indentation test separately under maximum load of 2500 µN applied
at the rate of 50 µN/sec and allowed to creep for 5 sec. All samples
showed sink-in behaviour i.e. hc
/hmax
ratio was less than 1 and in
accordance with the aforementioned fact [15,16], Cu which has low
n value (i.e. work hardening coefficient value is 0.44) showed higher
pile-up than the polymer and polymer composite samples for which n
value is close to 1. Figure 3 shows pile-up values as a function of H/Er
2
ratio (calculated from indentation heights from the same test result)
which is the indication of materials’ resistance to plastic deformation
[20]. It was observed that Cu falls relatively on the left side of H/Er2
axis showing highest pile-up/sink-in about 0.95, whereas, HDPE+FA
falls on extreme right side on X axis, showing higher H/Er
2
ratio with
Figure 2: Nano-indentation test profiles for Cu, LDPE and HDPE + FA samples.
Figure 3: Normalised pile-up/sink-in height of Cu, LDPE and HDPE+FA.
3. Ann Materials Sci Eng 2(2): id1022 (2015) - Page - 03
Bandyopadhyay S Austin Publishing Group
Submit your Manuscript | www.austinpublishinggroup.com
lower pile-up/sink-in value. LDPE is observed on X-axis between two
samples but more close to HDPE+FA sample.
Depending upon the fact that, material with high pile-up has
smaller cutting efficiency [1] and low H/Er2
ratio has low wear rate (Q)
[1], it can be stated that Cu, LDPE and HDPE+FA have wear rate and
cutting efficiency in ascending and descending order respectively. In
other words, Cu, LDPE and HDPE+FA represent hard, intermediate,
and soft material respectively.
Part B): Varying maximum load
The behaviour of Cu, LDPE and HDPE+FA was studied at
increasing load from 500 µN to 2500 µN keeping other parameters
such as loading/unloading rate and holding time constant. The H/
Er
2
and hc
/hmax
are plotted as a function of maximum load as shown
in Figure 4. It was observed that with increasing maximum load, H
and Er
were decreased for all samples (Figure 5) resulting in changed
H/Er
2
ratio as shown in Figure 4A. Reduction in H and Er
were also
observed by Fang et al. for another ductile polymer polycarbonate
[18]. But the change observed in this study in H/Er
2
is not similar for
all samples.
As the load was increased, wear rate decreased for Cu but
increased for the HDPE+FA. Intermediate hard materials show a
very small change in wear rate, this is probably because of the H and
Er
change independently as a function of maximum load (Figure 5),
which creates a difference in the 3 materials based on their different
individual modulus of elasticity (Cu having the highest and LDPE the
lowest). In this study, for Cu, it was observed that, H was changing
appreciably but not Er
, which indicates a decrease in H/Er
2
ratio.
Same trend was observed in case of LDPE with very small/negligible
change. On the other hand, rate of change of Er
of HDPE+FA was
higher than that of H resulting in lowered H/Er
2
values due to increase
in maximum load.
Figure 4B shows that increase in maximum applied load resulted
in higher hc
/hmax
ratio for Cu whereas no appreciable change happened
for LDPE whilst a decrease in hc
/hmax
for LDPE + FA was observed.
B)
Figure 4: The effect of increasing maximum load on, A) rate of wear and B) hc
/hmax
ratio of Cu, LDPE and HDPE + Fly ash.
Figure 5: Behaviour of H and Er
of A) Cu, B) LDPE and C) HDPE+FA; D) shows % change in H and Er
of Cu, LDPE and HDPE+FA.
4. Ann Materials Sci Eng 2(2): id1022 (2015) - Page - 04
Bandyopadhyay S Austin Publishing Group
Submit your Manuscript | www.austinpublishinggroup.com
This is attributed to the fact that, hc
is a function of Young’s modulus
(E) of the material [14] and hmax
vitally depends on applied load.
Hard materials with high Young’s modulus show high hc
eventually
resulting in high hc
/hmax
ratio at the same maximum load. Increase in
maximum load resulted into higher indentation depth (both hc
and
hmax
) in all the samples.
Due to increase in maximum load, the % increase observed in hc
was higher than that of hmax
in Cu, which results in increased hc
/hmax
ratio. On the other hand, for softer materials, (due to low Young’s
modulus), increment in hc
with respect to hmax
is either nearly equal
(for LDPE in the present case) or lower (for HDPE + FA) than that of
hmax
which ultimately gives constant or reduced hc
/hmax
respectively.
Part C): Influence of holding time
Figure 6 shows a comparative graph for creep values (creep value
is measured as the distance travelled by the indenter during constant
holding at maximum load) of three materials at different holding
times at constant maximum load of 2500 µN and loading/unloading
rate of 50 µN/sec. Hard material Cu, which shows low creep value is
plotted on secondary Y axis in order to compare with high creep value
materials LDPE and HDPE + FA on the same graph. As holding time
was increased, creep values of all samples were increased. At the same
time, it was observed that, over the same change in holding time,
the material having lower work hardening exponent showed a lower
increment in creep value as compared to that of having higher n value.
Figure 6: Comparison of creep values of Cu, LDPE and HDPE + FA over
different holding time.
A) B)
Figure 7: Effect of holding time on (A) H/Er
2
and (B) hc
/hmax
ratio.
After certain holding time Cu showed nearly constant creep value as
hard materials get hardened at small holding time whereas HDPE +
FA showed a gradual increase in creep value until it gets hardened
(not observed in this study for 30 sec holding time). It is evident from
Figure 6 that Cu reached its steady state at small holding time hence
it shows nearly constant creep after 20 sec; on the other hand, LDPE
and HDPE+fly ash do not achieve steady state in 20 sec and they show
gradual increase in creep with time - in fact these two latter materials
kept on showing creep even at 30 seconds - which presumably relates
to their different morphology, crystalline structure and much lower
modulus of elasticity as compared against copper’s.
Figures 7 and 8 show that although holding time affects creep
value of the material, resistance to plastic deformation i.e. H/Er
2
and
cutting efficiency of the material i.e. hc
/hmax
[14] remain unchanged for
all samples tested in this study. As can be seen in Figure 7A and Figure
8, H and Er
of Cu were reduced when holding time was increased
from 5 sec to 20 sec resulting into small jump in H/Er
2
at initial
stage. This decrease in H and Er
can be attributed to the increase in
creep which ultimately results in high indentation depth. Above this
holding time no appreciable change was observed in H and Er
(also
not in creep value in Figure 6) and Cu attained constant creep rate.
This discussion supports the suggestion made by other researchers
[13] to avoid the error in H and in Er
calculations by selecting high
holding time over short holding time.
LDPE and HDPE+FA in this work having higher work hardening
exponent showed linear (but negligible) change in H and Er
(reducing)
[1] resulting into constant creep rate and hc
/hmax
ratio, as observed by
Mandal et al. [14].
Part D): Influence of loading rate
Figure 9 and 10 show test results at varying loading rate with
constant maximum load (2500 µN) and holding time (5 sec). As
shown in Figure 9A and 9B, loading rate also did not show any effect
on wear rate and hc
/hmax
of all materials. However, a small change
was observed in H and Er
as Fig. 10 indicates. Low loading rate allows
more time for indenter to penetrate in the material surface resulting in
higher indentation depth resulting in less H as well as Er
. By contrast,
increase in loading rate reduces the indentation time and produce
higher hardness value. Another reason of high indentation depth at
low loading rate as mentioned in the literature is a small amount of
creep deformation that can be observed during loading period due to
low strain rate and longer loading time to reach maximum load [23].
5. Ann Materials Sci Eng 2(2): id1022 (2015) - Page - 05
Bandyopadhyay S Austin Publishing Group
Submit your Manuscript | www.austinpublishinggroup.com
In addition to these fundamental determinations, different
materials respond different ways depending upon the n value. In
this study, the material Cu with low n value showed appreciable
increase in H and Er
as loading rate increased but with no significant
change in the creep rate, whilst materials with high n value (LDPE
and HDPE+fly ash) showed slight increase in H and Er
with constant
creep rate. It is worth noting that in the literature similar behaviour
was observed in other materials with similar or close n value, for
example nickel surface with n = 0.38 [24] showed similar change in
H and Er
[13] as Cu (n= 0.44) [24]. Likewise polymer epoxy surface
showed same behaviour as reported by Fu K, et al. [17] as observed
in the present study for LDPE and HDPE + FA. Copper is a metal –
it is strain-hard enable at strains above yield strain typically around
0.2 %. By contrast the yield strain of plastics are much higher, so it is
Figure 8: Change in (A) hardness (H) and (B) reduced modulus (Er
) on varying holding time.
Figure 9: Effect of varying loading rate on (A) wear rate (H/Er
2
) and (B) hc
/hmax
of Cu, LDPE and HDPE+FA.
Figure 10: Effect of varying loading rate on (A) hardness and (B) reduced modulus of Cu, LDPE and HDPE+FA.
believed the graphs in Figure 10 B are still in the pre-yielding region
so the modulus is constant over that elastic deformation region.
Conclusion
The novelty of this project is as below: Copper is a metal believed
to have small and equiaxed grains; LDPE is a combination of polymer
crystals and amorphous region whereas the fly-ash-/HDPE composite
is a new type of engineering bi-phase composite material. All the
three materials are important from engineering application point of
view and it is interesting they undergo different types of deformation
under similar loading behavior.
The findings can be summarised as follows:
• Low work hardening exponent resulted in low wear rate