- The document discusses air bubble defects that can occur during dispensing nanoimprint lithography (D-NIL).
- It proposes that air bubbles may not fully dissolve during D-NIL, but instead relax to an equilibrium position at the nano-scale level.
- Theoretical modeling and computational simulations are used to study the dynamic behavior of air bubbles in two stages: an initial dissolution stage and a subsequent surface energy relaxation stage where the bubbles spread out to reach equilibrium.
New exploration challenges and current research demands
3D gravity modeling with 3D geology interpretations. In
the near future, multi-parameter and multi-dimensional
interpretations represent the observed and expected in situ
geology, geophysical, and petro-physical data that will be
used for join multi-parameter, multi-dimensional
inversions. We present an initial 3D gravity model of
Osage County in northeastern Oklahoma, where there is a
greater than 40 mGal, 100 km diameter semi-circular
gravity anomaly that cannot be effectively removed by
traditional gravity processing techniques.
This document discusses using spectroscopic ellipsometry to analyze molecular fractal surfaces through physical adsorption of water and other liquids. It provides background on existing surface adsorption theories and how they have been expanded to account for fractal surfaces. Experimental data is presented on water adsorption measured by ellipsometry on various surfaces like gold, silicon, and germanium. The data is analyzed using modified adsorption models that incorporate the fractal dimension of the surfaces to determine properties like monolayer coverage and surface dimensionality.
A Study of Anomalous Value of Free-Air Vertical Gradient for Density Determin...Premier Publishers
Underground Gravity Vertical Gradient is an important practice for prospecting underground densities, although in most cases it does not match the densities obtained directly in the laboratory from rock samples representative of the location. The densities of the laboratory samples were systematically lower when compared to the densities calculated by gravimetric determination suggesting some kind of systematic error. Several researchers propose different sources to explain these systematic errors including an anomalous value of the free-air vertical gradient. The anomalous value was admitted for the free-air vertical gradient in this paper to reinterpret the densities determination research made in a mine at Barberton, Ohio, in 1950, by gravimetric measurements and by laboratory rock samples. The results of both approaches reached similar densities agreeing with the free-air vertical gradient proposed.
This document discusses stress distribution in soils due to surface loads. It introduces Boussinesq's formula and Westergaard's formula for calculating vertical stress at a point in soil from a surface point load, based on elastic theory. Boussinesq's formula assumes the soil is elastic, isotropic, and homogeneous, while Westergaard's formula accounts for soil anisotropy. Formulas are also provided for calculating stress from line loads, strip loads, and loads beneath the corner of a rectangular foundation. Examples are given to demonstrate calculating stress at different points using the formulas.
Field and Theoretical Analysis of Accelerated Consolidation Using Vertical Dr...inventionjournals
Mumbai is the region consisting of soft compressible marine clay deposits. There are several construction problems on such soils and thus ground improvement is need to be carried out. Vertical drains is generally preferred technique as accelerated settlement is achieved during the construction phase itself if planned accordingly. The concept of vertical drains is based on the theory of three dimensional consolidation as described by Terzaghi (1943). Based on this concept, a consolidation programme is developed and an attempt is made to determine the field to laboratory coefficient of vertical consolidation ratio by Taylor’s Square Root of Time Method and Casagrande’s Logarithm of Time Fitting Method for this region. Based on this, the rate of consolidation and time required for consolidation in the field can be determined knowing the consolidation parameters. Equations are developed by using output of the programme and it is explained.
This document discusses soil phase relationships and classification. It defines key terms like void ratio, porosity, degree of saturation, density, specific gravity, water content and unit weight. It explains the relationships between these parameters and provides typical values for various soil types. For example, it states that the void ratios of natural sand deposits range from 0.51 to 0.85 and dry unit weights of granular soils range from 14 to 18 kN/m3. The document also includes two examples problems demonstrating calculations using the defined relationships.
Synthetic Modeling of 4D Borehole Microgravity for Fluid Movement Monitoring...Andika Perbawa
Now a day, the application of 4D surface
microgravity technology for identification density changes
of fluid reservoir is rapidly develop. But, it still has a
resolution limitation in vertical density variation.
Alternatively, borehole gravity meter technique can resolve
this problem.
In this research, to get effectiveness in measuring
borehole gravity response, a forward modeling code
program has been created for some complex synthetic
models. A complex model means that the reservoir has
some faults, anticline, syncline, and wedge out shape. And
then, a characteristic analysis of gravity anomaly response
has been done relates to amplitude, wavelength, boreholes
space and model geometry.
The result of synthetic modeling supported by
amplitude attribute analysis shows that the shape of
complex synthetic model and its depth can be identified
clearly. This paper shows a simulation of fluid movement
in reservoir with different models at different times. With
this simulation, we can see that 4D borehole microgravity
is useful to monitoring the fluid movement in reservoir.
1. The document discusses different types of settlement in shallow foundations, including immediate/elastic settlement, primary consolidation settlement, and secondary consolidation settlement.
2. It provides methods for calculating each type of settlement, making use of theories of elasticity, consolidation test data, and parameters like compression index.
3. Settlement predictions are generally satisfactory but better for inorganic clays; the time rate of consolidation settlement is often poorly estimated.
New exploration challenges and current research demands
3D gravity modeling with 3D geology interpretations. In
the near future, multi-parameter and multi-dimensional
interpretations represent the observed and expected in situ
geology, geophysical, and petro-physical data that will be
used for join multi-parameter, multi-dimensional
inversions. We present an initial 3D gravity model of
Osage County in northeastern Oklahoma, where there is a
greater than 40 mGal, 100 km diameter semi-circular
gravity anomaly that cannot be effectively removed by
traditional gravity processing techniques.
This document discusses using spectroscopic ellipsometry to analyze molecular fractal surfaces through physical adsorption of water and other liquids. It provides background on existing surface adsorption theories and how they have been expanded to account for fractal surfaces. Experimental data is presented on water adsorption measured by ellipsometry on various surfaces like gold, silicon, and germanium. The data is analyzed using modified adsorption models that incorporate the fractal dimension of the surfaces to determine properties like monolayer coverage and surface dimensionality.
A Study of Anomalous Value of Free-Air Vertical Gradient for Density Determin...Premier Publishers
Underground Gravity Vertical Gradient is an important practice for prospecting underground densities, although in most cases it does not match the densities obtained directly in the laboratory from rock samples representative of the location. The densities of the laboratory samples were systematically lower when compared to the densities calculated by gravimetric determination suggesting some kind of systematic error. Several researchers propose different sources to explain these systematic errors including an anomalous value of the free-air vertical gradient. The anomalous value was admitted for the free-air vertical gradient in this paper to reinterpret the densities determination research made in a mine at Barberton, Ohio, in 1950, by gravimetric measurements and by laboratory rock samples. The results of both approaches reached similar densities agreeing with the free-air vertical gradient proposed.
This document discusses stress distribution in soils due to surface loads. It introduces Boussinesq's formula and Westergaard's formula for calculating vertical stress at a point in soil from a surface point load, based on elastic theory. Boussinesq's formula assumes the soil is elastic, isotropic, and homogeneous, while Westergaard's formula accounts for soil anisotropy. Formulas are also provided for calculating stress from line loads, strip loads, and loads beneath the corner of a rectangular foundation. Examples are given to demonstrate calculating stress at different points using the formulas.
Field and Theoretical Analysis of Accelerated Consolidation Using Vertical Dr...inventionjournals
Mumbai is the region consisting of soft compressible marine clay deposits. There are several construction problems on such soils and thus ground improvement is need to be carried out. Vertical drains is generally preferred technique as accelerated settlement is achieved during the construction phase itself if planned accordingly. The concept of vertical drains is based on the theory of three dimensional consolidation as described by Terzaghi (1943). Based on this concept, a consolidation programme is developed and an attempt is made to determine the field to laboratory coefficient of vertical consolidation ratio by Taylor’s Square Root of Time Method and Casagrande’s Logarithm of Time Fitting Method for this region. Based on this, the rate of consolidation and time required for consolidation in the field can be determined knowing the consolidation parameters. Equations are developed by using output of the programme and it is explained.
This document discusses soil phase relationships and classification. It defines key terms like void ratio, porosity, degree of saturation, density, specific gravity, water content and unit weight. It explains the relationships between these parameters and provides typical values for various soil types. For example, it states that the void ratios of natural sand deposits range from 0.51 to 0.85 and dry unit weights of granular soils range from 14 to 18 kN/m3. The document also includes two examples problems demonstrating calculations using the defined relationships.
Synthetic Modeling of 4D Borehole Microgravity for Fluid Movement Monitoring...Andika Perbawa
Now a day, the application of 4D surface
microgravity technology for identification density changes
of fluid reservoir is rapidly develop. But, it still has a
resolution limitation in vertical density variation.
Alternatively, borehole gravity meter technique can resolve
this problem.
In this research, to get effectiveness in measuring
borehole gravity response, a forward modeling code
program has been created for some complex synthetic
models. A complex model means that the reservoir has
some faults, anticline, syncline, and wedge out shape. And
then, a characteristic analysis of gravity anomaly response
has been done relates to amplitude, wavelength, boreholes
space and model geometry.
The result of synthetic modeling supported by
amplitude attribute analysis shows that the shape of
complex synthetic model and its depth can be identified
clearly. This paper shows a simulation of fluid movement
in reservoir with different models at different times. With
this simulation, we can see that 4D borehole microgravity
is useful to monitoring the fluid movement in reservoir.
1. The document discusses different types of settlement in shallow foundations, including immediate/elastic settlement, primary consolidation settlement, and secondary consolidation settlement.
2. It provides methods for calculating each type of settlement, making use of theories of elasticity, consolidation test data, and parameters like compression index.
3. Settlement predictions are generally satisfactory but better for inorganic clays; the time rate of consolidation settlement is often poorly estimated.
Investigation of Supercavitation PhysicsSiyao Shao
1. The document summarizes an investigation into supercavitation physics conducted in two laboratories. It included studies of ventilated cavitation, configuration effects, and a comparison of ventilated and natural supercavitation.
2. Key findings included that results from the two laboratories for ventilated cavitation agreed well, and that a backward facing model provided better visualization of natural supercavitation compared to a forward facing model.
3. The formation and evolution of natural supercavitation was observed, including four stages of cavity development. Choking behavior, where cavity size remains constant despite pressure changes, was demonstrated and used to measure minimum cavitation numbers.
This document discusses stresses in soils due to applied loads using Boussinesq's theory. It provides the assumptions and equations for calculating vertical stresses due to concentrated point loads, line loads, and strip loads on the surface of a semi-infinite elastic medium. The stresses decrease with distance from the load and depth below the surface. Pressure distribution diagrams and isobars are used to illustrate the stress distributions. Numerical examples are provided to demonstrate calculating stresses at points below different load configurations.
This document summarizes a preliminary study of natural supercavitation conducted in a water tunnel. Experiments were performed using backward and forward facing models of different diameters. Key findings include: natural supercavities evolved rapidly from bubbly flows to stable shapes; choking occurred when further pressure reduction did not change cavity size; cavity closure types changed from twin vortices to quad vortices to re-entrant jets with increasing flow speed; and natural supercavity sizes agreed reasonably well with theoretical models. Future work may involve different model shapes, developing stable forward facing models, improved cavity dimension metrics, and temperature measurements.
Site investigation for multistorey buildingKiran Birdi
Preliminary and Detailed Investigation of Site.
It is done to check whether the site is feasible for Multistorey Building or not.
In this, I have calculated the Bearing Capacity of Soil by performing SPT.
1. The document discusses stress distribution in soils due to different types of loading, including point loads, line loads, triangular loads, strip loads, rectangular loads, and circular loads.
2. Several methods for estimating stress distribution are presented, including Boussinesq's method, Westergaard's method, and the use of influence factor charts and bulbs of pressure charts.
3. Factors that influence stress distribution include the size and shape of the loading area, load magnitude and type, soil type, depth, and distance from the load. Stress decreases with depth and distance from the load.
This document discusses soil improvement techniques for foundations. It describes mechanical compaction as the least expensive method, which involves removing weak soil and refilling/replacing it in layers with compaction. Two common compaction tests are described - the Standard Proctor Test and Modified Proctor Test - which involve compacting soil in a mold to determine the optimum moisture content and maximum dry density. Factors like moisture content and compactive effort influence compaction results.
Optimum replacement depth to control heave of swelling claysAhmed Ebid
The behavior of unsaturated swelling soils under changing of moisture content was intensively studied by many researchers since the 1950’s. Many proposed formulas and techniques were used to classify, describe and predict the swelling behavior and parameters of such type of soil. On the other hand, many techniques are used to allow structures to be founded on swelling soils without suffering any damages due to the soil heave. Replacing the swelling soil with granular mixture is one of the most famous and cheapest techniques especially in case of light structures on shallow layer of swelling soil. The aim of this research is to develop a simplified formula to estimate the heave of swelling soil considering the effect of replaced layer. The developed formula is used to estimate the required replacement depth to avoid damage due to excessive heave.
The document discusses effective stress in soils. It defines total stress, pore water pressure, and effective stress. Total stress is the load carried by the soil grains and water. Pore water pressure depends on depth and water flow conditions. Effective stress is the difference between total stress and pore water pressure, and represents the stress carried by the soil skeleton. Effective stress applies to saturated soils and influences properties like compressibility and consolidation. It is an imaginary parameter that cannot be directly measured but is important in soil mechanics analyses.
The document provides an overview of geomechanics concepts for drilling engineering. It discusses the importance of understanding pore pressure and formation strength for planning a successful well. Parameters like pore pressure, formation strength, and fracture gradient determine critical aspects of well design like mud weight profile, casing setting depths, casing string design, drill bit selection, and cementing procedures. The document then covers topics like normal vs. abnormal pressure regimes, mechanisms that cause abnormal pressures, modeling formation pressures, estimating pore pressures, and detecting abnormal pressures both pre-drill and while drilling.
This document discusses different types of shallow foundations including cantilever footings, combined footings, and mat foundations. It provides details on:
1. The design process for cantilever footings which involves iterative calculations to determine reactions and footing sizes to achieve uniform soil pressure.
2. Factors that influence the choice of foundation type including soil bearing capacity and building layout.
3. Design considerations for mat foundations on sand and clay soils including allowable bearing pressures.
This document discusses collapsible soils and how to assess their collapse potential and calculate expected settlements. There are two types of soils that exhibit volume changes with water content changes - collapsible soils that decrease in volume (collapse) when wetted and expansive soils that increase in volume (swell) when wetted. The document outlines methods to determine collapse potential from consolidation tests and calculate collapse settlements using a double oedometer test procedure. It provides examples of applying these methods to calculate collapse settlements for normally consolidated and overconsolidated soil conditions. Foundation design in collapsible soils requires special consideration due to the risk of large wetting-induced settlements.
This document provides an overview of soil compressibility and consolidation. It defines consolidation as the process by which saturated clay compresses over time as water drains out of the soil mass and load is gradually transferred from pore water to the soil skeleton. A key aspect of consolidation discussed is the one-dimensional consolidation theory, which models clay layers constrained laterally between impermeable boundaries. The document also describes the consolidometer test apparatus used to measure a soil's compressibility properties and generate pressure-void ratio curves through standardized loading and unloading steps.
1. This document provides information about vertical stresses below applied loads on the ground surface. It discusses theories of elasticity and how soils can be treated as quasi-elastic materials under limited loading conditions.
2. It presents Boussinesq's formula and Westergaard's modified formula for calculating vertical stresses below a point load on the ground surface. It also discusses pressure isobars and how they can be used to determine a significant depth below applied loads.
3. The document concludes with examples of calculating vertical stresses using Boussinesq's and Westergaard's formulas, and an example of determining pressure isobars and significant depth. Homework assignments are also provided applying the stress calculation methods.
This document discusses preconsolidation pressure in soils. It defines preconsolidation pressure as the maximum effective vertical overburden stress a soil sample has experienced in the past. Though it cannot be directly measured, it can be estimated using methods like analyzing the curvature of a consolidation curve. A soil is considered normally consolidated if the current vertical effective stress is equal to or greater than the preconsolidation pressure. The document also lists factors that can cause a soil to approach its preconsolidation pressure, such as changes in total stress, pore water pressure, soil structure, or environmental conditions. Finally, it states that knowing the preconsolidation pressure is important for predicting settlement, site preparation for construction, and determining appropriate
This chapter discusses Terzaghi's bearing capacity theory for determining the ultimate bearing capacity of shallow foundations. It summarizes the key assumptions of Terzaghi's theory, including homogeneous, isotropic soil; two-dimensional problem; general shear failure; and vertical, symmetrical loading. It describes the failure mechanism with three zones - an elastic central zone beneath the footing, and two radial shear zones on the sides that meet the ground surface at angles of 45° - φ/2. Terzaghi's theory uses a semi-empirical equation to calculate ultimate bearing capacity based on soil properties of cohesion, friction, and the effective overburden pressure at the foundation level.
Using Lattice Boltzmann Method to Investigate the Effects of Porous Media on ...A Behzadmehr
1) The document describes a numerical study using the lattice Boltzmann method to investigate heat transfer from a solid block inside a porous media-filled channel.
2) The effects of porosity and thermal conductivity ratio on fluid flow patterns and temperature fields were examined.
3) Higher porosity and lower thermal conductivity ratio resulted in lower fluid temperatures, as increased porosity reduces the effective thermal conductivity and thus heat transfer between the fluid and solid block.
The extensive slide-pack starts with introducing physics and basics on geomechanics. A lot of stress and rock strength concepts are explored. Then it moves on to explain the importance of the discipline for drilling, injection, sanding. Apart from giving theory to understand more difficult content that follow, it throws in practical application and prepares good ground for further study of geomechanical literature.
BOUSSINESQ THEORY
VERTICAL STRESS DUE TO POINT LOAD
TABLE FOR VALUES OF BOUSSINESQ’S COEFFICIENT (퐼_퐵)
SOME POINTS FOR USING THE BOUSSINESQ’S EQUATION.
LIMITATIONS OF BOUSSINESQ’S SOLUTION.
- The one-dimensional consolidation test is performed in an oedometer to determine the consolidation properties of soils.
- Results are presented as plots of void ratio (e) versus effective stress (σ') on linear and logarithmic scales. Key properties like compression index (Cc), recompression index (Cr), and preconsolidation pressure (σ'c) can be determined.
- Primary consolidation settlement can be calculated from the e-logσ' curve using Cc, or from coefficients of volume change like mv. Commonly the midpoint stress increase or weighted average method are used.
Splashing mechanism during impact of a hollow droplet on a substrate(156)docamarjitkene
1) The document summarizes a numerical study comparing the splashing behavior of continuous and hollow molten droplets during impact on a substrate.
2) For continuous droplets, splashing occurs very early during spreading due to high spreading velocities creating instabilities at the edge, detaching satellite droplets that solidify and create barriers for further spreading.
3) In contrast, hollow droplets were found to experience significantly less splashing due to a new phenomenon of counter liquid jetting during flattening, which suppresses instabilities.
The document describes the physics of bubbles that form during boiling water. It discusses the different types of bubbles - air bubbles (AB), vapor bubbles (VB), and microscopic air bubbles (MAB) - that appear at various stages of the boiling process. An experiment detecting the noises produced during boiling identified three main sources: 1) detachment of ABs before boiling, 2) collapse of VBs in the water, and 3) appearance of MABs under the surface. The theoretical description of bubble evolution is in good agreement with experiments. Questions are then provided to analyze the physics governing the growth, detachment, and motion of the different bubble types using concepts like pressure, surface tension, viscosity, and the Stokes formula.
Investigation of Supercavitation PhysicsSiyao Shao
1. The document summarizes an investigation into supercavitation physics conducted in two laboratories. It included studies of ventilated cavitation, configuration effects, and a comparison of ventilated and natural supercavitation.
2. Key findings included that results from the two laboratories for ventilated cavitation agreed well, and that a backward facing model provided better visualization of natural supercavitation compared to a forward facing model.
3. The formation and evolution of natural supercavitation was observed, including four stages of cavity development. Choking behavior, where cavity size remains constant despite pressure changes, was demonstrated and used to measure minimum cavitation numbers.
This document discusses stresses in soils due to applied loads using Boussinesq's theory. It provides the assumptions and equations for calculating vertical stresses due to concentrated point loads, line loads, and strip loads on the surface of a semi-infinite elastic medium. The stresses decrease with distance from the load and depth below the surface. Pressure distribution diagrams and isobars are used to illustrate the stress distributions. Numerical examples are provided to demonstrate calculating stresses at points below different load configurations.
This document summarizes a preliminary study of natural supercavitation conducted in a water tunnel. Experiments were performed using backward and forward facing models of different diameters. Key findings include: natural supercavities evolved rapidly from bubbly flows to stable shapes; choking occurred when further pressure reduction did not change cavity size; cavity closure types changed from twin vortices to quad vortices to re-entrant jets with increasing flow speed; and natural supercavity sizes agreed reasonably well with theoretical models. Future work may involve different model shapes, developing stable forward facing models, improved cavity dimension metrics, and temperature measurements.
Site investigation for multistorey buildingKiran Birdi
Preliminary and Detailed Investigation of Site.
It is done to check whether the site is feasible for Multistorey Building or not.
In this, I have calculated the Bearing Capacity of Soil by performing SPT.
1. The document discusses stress distribution in soils due to different types of loading, including point loads, line loads, triangular loads, strip loads, rectangular loads, and circular loads.
2. Several methods for estimating stress distribution are presented, including Boussinesq's method, Westergaard's method, and the use of influence factor charts and bulbs of pressure charts.
3. Factors that influence stress distribution include the size and shape of the loading area, load magnitude and type, soil type, depth, and distance from the load. Stress decreases with depth and distance from the load.
This document discusses soil improvement techniques for foundations. It describes mechanical compaction as the least expensive method, which involves removing weak soil and refilling/replacing it in layers with compaction. Two common compaction tests are described - the Standard Proctor Test and Modified Proctor Test - which involve compacting soil in a mold to determine the optimum moisture content and maximum dry density. Factors like moisture content and compactive effort influence compaction results.
Optimum replacement depth to control heave of swelling claysAhmed Ebid
The behavior of unsaturated swelling soils under changing of moisture content was intensively studied by many researchers since the 1950’s. Many proposed formulas and techniques were used to classify, describe and predict the swelling behavior and parameters of such type of soil. On the other hand, many techniques are used to allow structures to be founded on swelling soils without suffering any damages due to the soil heave. Replacing the swelling soil with granular mixture is one of the most famous and cheapest techniques especially in case of light structures on shallow layer of swelling soil. The aim of this research is to develop a simplified formula to estimate the heave of swelling soil considering the effect of replaced layer. The developed formula is used to estimate the required replacement depth to avoid damage due to excessive heave.
The document discusses effective stress in soils. It defines total stress, pore water pressure, and effective stress. Total stress is the load carried by the soil grains and water. Pore water pressure depends on depth and water flow conditions. Effective stress is the difference between total stress and pore water pressure, and represents the stress carried by the soil skeleton. Effective stress applies to saturated soils and influences properties like compressibility and consolidation. It is an imaginary parameter that cannot be directly measured but is important in soil mechanics analyses.
The document provides an overview of geomechanics concepts for drilling engineering. It discusses the importance of understanding pore pressure and formation strength for planning a successful well. Parameters like pore pressure, formation strength, and fracture gradient determine critical aspects of well design like mud weight profile, casing setting depths, casing string design, drill bit selection, and cementing procedures. The document then covers topics like normal vs. abnormal pressure regimes, mechanisms that cause abnormal pressures, modeling formation pressures, estimating pore pressures, and detecting abnormal pressures both pre-drill and while drilling.
This document discusses different types of shallow foundations including cantilever footings, combined footings, and mat foundations. It provides details on:
1. The design process for cantilever footings which involves iterative calculations to determine reactions and footing sizes to achieve uniform soil pressure.
2. Factors that influence the choice of foundation type including soil bearing capacity and building layout.
3. Design considerations for mat foundations on sand and clay soils including allowable bearing pressures.
This document discusses collapsible soils and how to assess their collapse potential and calculate expected settlements. There are two types of soils that exhibit volume changes with water content changes - collapsible soils that decrease in volume (collapse) when wetted and expansive soils that increase in volume (swell) when wetted. The document outlines methods to determine collapse potential from consolidation tests and calculate collapse settlements using a double oedometer test procedure. It provides examples of applying these methods to calculate collapse settlements for normally consolidated and overconsolidated soil conditions. Foundation design in collapsible soils requires special consideration due to the risk of large wetting-induced settlements.
This document provides an overview of soil compressibility and consolidation. It defines consolidation as the process by which saturated clay compresses over time as water drains out of the soil mass and load is gradually transferred from pore water to the soil skeleton. A key aspect of consolidation discussed is the one-dimensional consolidation theory, which models clay layers constrained laterally between impermeable boundaries. The document also describes the consolidometer test apparatus used to measure a soil's compressibility properties and generate pressure-void ratio curves through standardized loading and unloading steps.
1. This document provides information about vertical stresses below applied loads on the ground surface. It discusses theories of elasticity and how soils can be treated as quasi-elastic materials under limited loading conditions.
2. It presents Boussinesq's formula and Westergaard's modified formula for calculating vertical stresses below a point load on the ground surface. It also discusses pressure isobars and how they can be used to determine a significant depth below applied loads.
3. The document concludes with examples of calculating vertical stresses using Boussinesq's and Westergaard's formulas, and an example of determining pressure isobars and significant depth. Homework assignments are also provided applying the stress calculation methods.
This document discusses preconsolidation pressure in soils. It defines preconsolidation pressure as the maximum effective vertical overburden stress a soil sample has experienced in the past. Though it cannot be directly measured, it can be estimated using methods like analyzing the curvature of a consolidation curve. A soil is considered normally consolidated if the current vertical effective stress is equal to or greater than the preconsolidation pressure. The document also lists factors that can cause a soil to approach its preconsolidation pressure, such as changes in total stress, pore water pressure, soil structure, or environmental conditions. Finally, it states that knowing the preconsolidation pressure is important for predicting settlement, site preparation for construction, and determining appropriate
This chapter discusses Terzaghi's bearing capacity theory for determining the ultimate bearing capacity of shallow foundations. It summarizes the key assumptions of Terzaghi's theory, including homogeneous, isotropic soil; two-dimensional problem; general shear failure; and vertical, symmetrical loading. It describes the failure mechanism with three zones - an elastic central zone beneath the footing, and two radial shear zones on the sides that meet the ground surface at angles of 45° - φ/2. Terzaghi's theory uses a semi-empirical equation to calculate ultimate bearing capacity based on soil properties of cohesion, friction, and the effective overburden pressure at the foundation level.
Using Lattice Boltzmann Method to Investigate the Effects of Porous Media on ...A Behzadmehr
1) The document describes a numerical study using the lattice Boltzmann method to investigate heat transfer from a solid block inside a porous media-filled channel.
2) The effects of porosity and thermal conductivity ratio on fluid flow patterns and temperature fields were examined.
3) Higher porosity and lower thermal conductivity ratio resulted in lower fluid temperatures, as increased porosity reduces the effective thermal conductivity and thus heat transfer between the fluid and solid block.
The extensive slide-pack starts with introducing physics and basics on geomechanics. A lot of stress and rock strength concepts are explored. Then it moves on to explain the importance of the discipline for drilling, injection, sanding. Apart from giving theory to understand more difficult content that follow, it throws in practical application and prepares good ground for further study of geomechanical literature.
BOUSSINESQ THEORY
VERTICAL STRESS DUE TO POINT LOAD
TABLE FOR VALUES OF BOUSSINESQ’S COEFFICIENT (퐼_퐵)
SOME POINTS FOR USING THE BOUSSINESQ’S EQUATION.
LIMITATIONS OF BOUSSINESQ’S SOLUTION.
- The one-dimensional consolidation test is performed in an oedometer to determine the consolidation properties of soils.
- Results are presented as plots of void ratio (e) versus effective stress (σ') on linear and logarithmic scales. Key properties like compression index (Cc), recompression index (Cr), and preconsolidation pressure (σ'c) can be determined.
- Primary consolidation settlement can be calculated from the e-logσ' curve using Cc, or from coefficients of volume change like mv. Commonly the midpoint stress increase or weighted average method are used.
Splashing mechanism during impact of a hollow droplet on a substrate(156)docamarjitkene
1) The document summarizes a numerical study comparing the splashing behavior of continuous and hollow molten droplets during impact on a substrate.
2) For continuous droplets, splashing occurs very early during spreading due to high spreading velocities creating instabilities at the edge, detaching satellite droplets that solidify and create barriers for further spreading.
3) In contrast, hollow droplets were found to experience significantly less splashing due to a new phenomenon of counter liquid jetting during flattening, which suppresses instabilities.
The document describes the physics of bubbles that form during boiling water. It discusses the different types of bubbles - air bubbles (AB), vapor bubbles (VB), and microscopic air bubbles (MAB) - that appear at various stages of the boiling process. An experiment detecting the noises produced during boiling identified three main sources: 1) detachment of ABs before boiling, 2) collapse of VBs in the water, and 3) appearance of MABs under the surface. The theoretical description of bubble evolution is in good agreement with experiments. Questions are then provided to analyze the physics governing the growth, detachment, and motion of the different bubble types using concepts like pressure, surface tension, viscosity, and the Stokes formula.
The document describes three experiments conducted to study surface tension: 1) Using a tapered vessel filled with water, where the water level rises as the gap narrows due to surface tension. 2) Filling capillary tubes with water, where the water level rises higher in narrower tubes due to the capillary effect. 3) Using a surface tension balance to directly measure the surface tension of liquids by determining the force required to break the liquid's surface. The experiments aim to observe and calculate the surface tension of liquids and understand how it causes behaviors such as the rise of water in narrow spaces.
Phase transformation and volume collapse of sm bi under high pressureAlexander Decker
The document summarizes a study on the high-pressure phase transition of samarium bismuth (SmBi). The study used a modified three-body interaction potential model to investigate the phase transition pressure and associated volume collapse of SmBi. The model takes into account long-range Coulombic interactions, three-body interactions, van der Waals interactions, overlap repulsion, polarizability, and zero-point energy. The calculations predict a phase transition from the normal NaCl structure to a distorted CsCl structure at 17.8 GPa, with an 8.41% volume collapse. These values agree well with previous experimental measurements of 18.3 GPa transition pressure and 8.25% volume collapse. Thus, the
This document summarizes research on forming mesoscopic patterns of molecular aggregates on solid surfaces using amphiphilic polymers. Key points:
1) A two-dimensional honeycomb structure with micron-sized cells was formed by casting a chloroform solution of an amphiphilic polymer on a solid surface at high humidity.
2) This simple method can be used to pattern a variety of amphiphilic polymers, including functional polymers.
3) The proposed mechanism involves the condensation of water droplets on the solution which are then packed into a honeycomb structure as the solution evaporates and recedes across the surface.
The aim of the project is to find the best model from literature to fit experimental data on particle resuspension from indoor surfaces. The most suitable models will be implemented in Matlab and Excel and their results will be compared to experiments. The rock and roll model is not suitable due to low friction velocities used. The resuspension rate predicted by the Kim model was faster than experiments. A new dimensional model was developed and its coefficient is consistent with literature values.
This document provides guidance on answering subjective physics questions in the SPM paper 2 exam. It discusses the following:
1) The 3 sections of the exam - Section A has 8 questions worth 60 marks to be answered in 90 minutes. Section B has 2 questions worth 20 marks each to be answered in 30 minutes. Section C has 2 questions worth 20 marks each also to be answered in 30 minutes.
2) Types of questions in each section - Section A focuses on knowledge, understanding and application. Section B involves conceptualizing. Section C requires problem solving or decision making.
3) Strategies for answering questions effectively such as reading the question multiple times and highlighting key words, answering questions
This document summarizes research on modeling the vibration of prestressed membrane structures in air. It begins with an analytical solution for an infinite flat membrane that derives equations showing air introduces an added mass that depends on the membrane and air wave numbers. Experiments on triangular membranes measured resonant frequencies and modes in air. A finite element method is then presented and validated against the analytical solution and experiments. The method accurately models air-membrane interaction and can simplify ground testing of large deployable structures by simulating behavior in air rather than requiring vacuum chambers.
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Similar to Air Bubble Defects in Dispensing Nanoimprint Lithography-Nan Li (20)
Air Bubble Defects in Dispensing Nanoimprint Lithography-Nan Li
1. Nan Li
University of Michigan
1
Air Bubble Defects in Dispensing Nanoimprint Lithography
Abstract
We report a theoretical study and dynamic simulation to understand the dynamic behavior of the
air bubble defects in Dispensing Nanoimprint Lithography (D-NIL), which is one of the biggest
challenges in this technique. Continued with previous research report of air bubble formation and
dissolution in dispensing nanoimprint lithography [5], which found mechanisms for air bubble
formation (multi-droplet encircling) and air bubble dissolution as a function of time, we draw a
hypnosis that the air bubble, instead of dissolving completely in the resist liquid, still remains in
nano-scale and experience the surface energy relaxation. We developed theoretical and simulation
evidence to support our hypoesis. Our key conclusions from the study, which has significant
practical importance, is that air in a bubble can relax to the equilibrium position before completely
dissolving in a resist liquid.
Key Words
Dispensing-based nanoimprint lithography, air bubble defect, air bubble surface energy
relaxation
1. Introduction
Nanoimprint lithography (NIL) is a proven technology with the key advantage of high resolution.
It has shown the capability of patterning structures smaller than 10 nm with a high throughput [1,
2]. One of the NIL processes under current study is dispensing-based NIL (D-NIL), which
generally describes a group of relevant and similar procedures using dispensed liquid resist
including micromoulding in capillaries (MIMIC) [3], and step-and-flash imprint lithography
(SFIL). In this technique, the resist liquid is dropped on the resist as droplets (Fig.1 (a)). Then a
mold is used to push the droplets to merge together into a thin film (Fig.1 (b)).The resist liquid is
then cured by either photos, heat, or both (Fig.1 (c)), and leave a solid imprint pattern on the
substrat e(Fig.1 (d)).
2. Nan Li
University of Michigan
2
Figure 1: Schematic of dispensing nanoimprint lithography (D-NIL).
However, there still challenges remaining in this process. One of the biggest challenges in this
method is the air bubble defect. The air bubble defect is caused during the multiple droplets
merging process, in which the air bubble is trapped in the center of the resist, due to the enclosure
of the escape paths (Fig. 2).
Figure 2: Schematic of bubble formation due to multi-droplet encircling
2. Dynamic Behavior of Air Bubble
After the air bubble is trapped in the center of the resist, the dynamic behavior of air bubble is
presented below as two stages: (2.1) dissolution stage and (2.2) surface energy relaxation stage
The dynamic behavior in dissolution stage has already been well studied by Xiaogan Liang in 2007
using experimental and theoretical model (Fig.3, [5]). Our study is a continuous study based on
this previous research and focus on the second stage: surface energy relaxation stage.
2.1 Dissolution Stage
After the air bubble is trapped in the center of the resist, it will first experience the dissolution
stage. Figure 3 shows the study results that air bubble can dissolve with time, using the real-time
observation of the air bubble dissolution (Fig 3(a)) and average bubble diameter as a function of
3. Nan Li
University of Michigan
3
time (Fig 3(b)). However, the scale of this study is in micron meter and the bubble diameter did
not reach zero, we could doubt the air bubble did not dissolve completely in the resist. An recent
industrial email from Seagate company proved our doubt by showing the nano-scale air bubble
defects found in the resist pattern (Fig.4 (a)). So we developed further study to understand the
dynamic behavior of air bubble in nano-scale after dissolution stage, where the most parts of
bubble has been dissolved.
(a) (b)
Figure 3: (a) Real-time observation of an air bubble encircled by multiple droplets and the
bubble shrinking due to the air dissolution into the resist. (b) The simulated (—) and measured ( )
time evolution of average bubble diameter as a function of bubble initial size for a given set of
NIL parameters [5].
2.2 Surface Energy Relaxation Stage
After the most parts of the air bubble dissolved in the resist liquid, we assume small parts of it still
remain in nano-scale, and then experience surface energy relaxation stage. The hypothesis of the
dynamic behavior of air bubble in this stage is made by assuming the bubble will spread out and
relax follwing the dash line in figure.4 (b).
(a)
(a)
4. Nan Li
University of Michigan
4
(b)
Figure 4: (a) Geometry of the Air bubble defects found in the resist pattern, and (b) hypothesis of
the dynamic behavior of air bubble during surface energy relaxation: the bubble will spread out
and relax follwing the dash line.
3. Theoretical and Simulation Study of the Air Bubble Surface Energy Relaxation Behavior
We developed theoretical and simulation evidence to support our hypothesis of the surface energy
relaxation of the air bubble. After dissolution, the model assumes a 100 nm single air bubble
trapped at the central part of an already merged resist film; the outer boundary of the resist film is
far away from the bubble; the fluidic flow can be described as laminar flow; the bubble relaxation
and the resist flow around the bubble are axially symmetrical; the pressure is constant and the gas
trapped in the bubbles is mainly composed of air.
Figure 5 shows the geometry of the theoretical model, in which a single bubble is initially located
at the center of a thin resist film sandwiched between a rigid mold and a substrate.
(a)
(b)
Figure 5: (a) Geometry and parameters of a single air bubble initially located at the center of a
resist liquid sandwiched between a mold and a substrate, and (b) the illustration of the final
position of the air bubble after the surface energy relaxation.
3.1 Theoretical Study
During the surface energy relaxation process, the dynamic behavior of air bubble is described by
the Young's equation [6], which is obtained by projecting the equilibrium forces on the solid plane,
and used to describe the surface tensions between three phases: solid, liquid, and gas (Fig.6).
Where γLS is the liquid-solid interfacial free energy, γLG is the liquid-gas interfacial free energy,
γGS is gas-solid interfacial free energy, θ1and θ2 is the contact angel.
5. Nan Li
University of Michigan
5
γLS + γLGcosθ1 = γGS (1)
When γLS + γLGcosθ1 > γGS as the initial condition (Fig.6 (a)), the air bubble will spreads driven
by the unbalanced surface tension. When γLS + γLGcosθ1 = γGS (Fig.6 (b)), the air bubble will
stop spreading and stay its equilibrium position which has lowest its surface energy.
(a)
(b)
Figure 6.Schemetic interface tensions between solid(mold), liquid(resist), and gas(air bubble);(a)
in initial condition, air bubble will spreads because the unbalanced surface energy in order to
lower surface energy, until (b) the air bubble will stop spreads and keep staying its equilibrium
position which has lowest its surface energy.
The pressure difference between the inside and outside of bubble, Pb − Po, is described by Laplace
pressure equation (Eq. (2)), which depends upon the surface tension σ, the radius 𝑅 of the bubble.
Where Pbis the pressure inside the bubble and Pois the ambient pressure. During this spreading out
process, the pressure difference decrease because the radius of the bubble increase. Thus
dissolution decrease and bubble will stay in this equilibrium condition for a long time that formed
air bubble defects in the resist.
Pb − Po =
4σ
R
(2)
3.2 Simulation Study
The dynamic behavior of air bubble surface energy relaxation was simulated by computational
fluid dynamics (CFD) using ANSYS 16.1-Fluent. Since the minimum scale of this simulation
software IS millimeter, dimensional analysis is used for scaling the parameters between theoretical
prototype above and simulation model.
We assume the viscosity μ of the resist flow depended on Eq. (3): μ = f(ρ, V, L, σ), where ρ is the
density of the resist, V is the resist flow velocity, L is the characteristic length, and σ is the surface
tension. With dimensional group analysis, we can immediately reduce Eq. (3) to the equivalent
form of dimensionless groups.
6. Nan Li
University of Michigan
6
ρVL
μ
= g(
∆P
1
2
ρV2
,
ρV2L
σ
)
(4, 5)
Re = g( Eu, We)
To achieve dynamic similarity requires duplication of these dimensionless groups, where
subscripts 𝑚 and 𝑝 mean model and prototype.
Rem = Rep,
Eum = Eup,
Wem = Wep
(6)
Vp
Vm
=
ρm
ρp
μp
μm
Lm
Lp
= √
ρmLm
ρpLp (7,8)
μm
μp
= √
ρmLm
ρpLp
Assuming ρm = ρp, Lm = 1 mm, Lp = 100 nm, so
μm
μp
= 100. Since the material properties of
the resist liquid and air bubble was assumed water and air, the viscosity of the resist liquid and air
bubble was set 100 times bigger than the standard viscosity properties (Table 1. (a)). Other
numerical parameters, setting-up and geometry is presented in table 1 and figure 7 below.
(a)
Physical parameters Symbols Value
Surface tension σ
Radius of the bubble R 0.42 mm
Pressure inside the
bubble
Pb
Ambient pressure Po 1.01× 105
Pa
Density of the resist ρ 998.2 kg/m3
Resist flow velocity V
Characteristic length L 1 mm
Contact angel θ1 160 degree
7. Nan Li
University of Michigan
7
(b)
Setting-Up Parameters
General Pressure-based, Transient
Models
Volume of Fluid: two phases
Laminar
Materials
Bubble:
standard air form default database,
Viscosity [kg/m-s]:0.00179
Resist:
standard water-liquid form default database,
Viscosity [kg/m-s]: 0.1003
Boundary conditions
Pressure outlet: water backflow fraction:1
Axisymmetric
Solution Method Simple C
Table 1: (a) Numerical values of physical parameters, and (b) model set-up parameters used in
the simulation.
Figure 7: Axisymmetric geometry of the used in the simulation at equilibriums condition. The
axis boundary type is used as the centerline (marked in dash line ) of the geometry.
The simulatyion result regarding the volume fraction of the air bubble and pressure evolution of
the air bubble with a function of time, during the air bubble surface energy relaxation stage, is
presented in figure 8. We can see from the 0.0001sec to 0.01 sec, the pressure difference between
the bubble inside and outside is large since the energy contours cross a large range. After 0.02s,
the pressure difference becomes less since the smaller range of enegy contours. Refering the
volume fraction of the air bubble, we can draw the conclusion the bubble reached its equilibrium
condition and formed air bubble defects in the resist.
8. Nan Li
University of Michigan
8
Figure 8: The volume fraction of the air bubble in red color (left) and pressure evolution of the
air bubble (right) with a function of time.
9. Nan Li
University of Michigan
9
Conclusion
Nanoimprint lithography has key adavantage in high resolution comparing to the conventional
technics such as optical lithography. However, one of the biggest chanllege in this manufacturing
process is the air bubble defects fomed in the resist. Our objective of this paper is to understand
the dynamica behavior of air bubble. The air bubble is found to experience two stages: dissolosion
and surface energy relaxation. Our project focus on the second stage and made hypoesis of the air
bubble’s daynamic havior. Finally we developed theoretical and simulation evidence to support
our hypoesis that air in a bubble can relax to the equilibrium position before completely dissolving
in a resist liquid.
10. Nan Li
University of Michigan
10
References
[1] S. Y. Chou, P. R. Krauss, and P. J. Renstrom, “Imprint of sub-25 nm vias and trenches in
polymers,” Appl. Phys. Lett. Applied Physics Letters, pp. 3114–3114.
[2] S. Y. Chou, P. R. Krauss, and P. J. Renstrom, “Imprint Lithography with 25-Nanometer
Resolution,” Science, pp. 85–87, 1996.
[3] E. Kim, Y. Xia, and G. M. Whitesides, “Polymer microstructures formed by moulding in
capillaries,” Nature, pp. 581–584, 1995.
[4] M. Colburn, S. C. Johnson, M. D. Stewart, S. Damle, T. C. Bailey, B. Choi, M. Wedlake, T.
B. Michaelson, S. V. Sreenivasan, J. G. Ekerdt, and C. G. Willson, “,” Emerging Lithographic
Technologies III, 1999.
[5] X. Liang, H. Tan, Z. Fu, and S. Y. Chou, “Air bubble formation and dissolution in dispensing
nanoimprint lithography,” Nanotechnology, pp. 025303–025303, 2006.
[6] “ramé-hart Contact Angle,” ramé-hart Contact Angle. [Online]. Available at:
http://www.ramehart.com/contactangle.htm. [Accessed: Feb-2015].
[7] M. C. Weinberg, “Surface tension effects in gas bubble dissolution and growth,” Chemical
Engineering Science, pp. 137–141.
[8] R. W. Fox and R. W. Fox, Fox and McDonald's introduction to fluid mechanics, 8th ed.
Hoboken, NJ: John Wiley & Sons, Inc., 2011, p. 305.