The document summarizes research into the origin of rippled structures that form on the surface of silicon during molecular beam epitaxy growth on Si(001) substrates. Through experiments using x-ray crystallography, optical microscopy, and atomic force microscopy, the researchers found that the rippled structure is caused by correlated kink bunching along step edges, rather than by step bunching. They present a model wherein the inherent discreteness of growth can cause deviations from the equilibrium kink distribution large enough to induce step-step interactions and the formation of ripples.
1) The document analyzes volume curvature attributes in seismic data to identify subtle faults and fractures in a carbonate reservoir.
2) Volume curvature attributes, such as most positive and most negative, were better able to illuminate discontinuities and flexures associated with fracture zones and minor faults not evident in other seismic attributes or manual interpretation.
3) The identified lineaments from curvature attributes correlated with zones of high fracture density observed in well data, suggesting they could delineate faults with offsets below seismic resolution.
Borehole breakouts and insitu rock stressrana ammad
This document provides a review of borehole breakouts and their use as indicators of in-situ rock stress. It discusses how breakouts form as a result of spalling parallel to the minimum horizontal stress during drilling. Breakout analysis can provide information on stress orientation important for reservoir applications like well placement, production strategies, and hydraulic fracturing. It also discusses uses for drilling, crustal stress studies, rock mechanics, and outlines the history of understanding breakouts as stress indicators. The document reviews methods for identifying breakouts using tools like dipmeters and borehole imaging and debates using breakout geometry to estimate stress magnitudes.
Prediction Of Ground Settlement Response To Sheet Pile Extraction (P. Mc Gough)pmcgough
This paper presents a new empirical method for predicting ground surface settlement in response to sheet pile extraction. The method is based on field measurement data from several projects in Perth, Western Australia involving the extraction of sheet piles installed in sandy and soft clay soils. A design procedure is proposed that relates the predicted settlement profile to factors such as the sheet pile cross-section, depth, soil type, and amount of soil volume replaced after extraction. The method is shown to correlate well with limited published data on this topic. The effect of soil type on an "adhesion factor" used in the predictions is also examined.
Evaluation of Structural Geology of Jabal OmarIJERD Editor
The proposed Jabal Omar Development project includes several multi-storey buildings, roads, bridges and below ground structures. Dykes and joints are the most common geological features in the area; they vary in thickness and orientation. The spacing between adjacent discontinuities largely control the size of individual blocks of rock masses which govern the stability of rock structures. The shearing and faulting system normally associated with tectonic movement making the area very weak, highly weathered and unstable. All Structural geological units analyzed using stereographic projection
Lateral resolution and lithological interpretation of surface wave profi lingAdam O'Neill
This document summarizes research on using surface wave profiling to characterize near-surface geology. It discusses issues with lateral resolution when imaging subsurface features like sinkholes. Numerical modeling of a sinkhole in buried hard rock shows that wider sinkholes are resolved better than narrow ones. Field data from Western Australia that combines surface wave and electrical resistivity data illustrates improved lithological interpretation when both methods are used. The researchers investigate ways to enhance lateral resolution, such as using non-linear geophone spacing. They also demonstrate data-driven classification of rock types based on resistivity and shear wave velocity measurements.
The document discusses rock mass properties and the Hoek-Brown failure criterion for estimating the strength of jointed rock masses. It presents the generalized Hoek-Brown criterion equation and describes how to determine the intact rock properties of uniaxial compressive strength (σci) and the Hoek-Brown constant (mi) from triaxial test data or estimates. It also discusses estimating the Geological Strength Index (GSI) of the rock mass.
This document summarizes a seismic study of a coal deposit in Wabamun, Alberta. It provides background on the study area and coal deposit geology. It then describes the acquisition and processing of seismic reflection data from two lines over the deposit. The data is analyzed and interpreted, with control from a well. On one line, variations in the seismic character of the coal reflection are correlated to stratigraphic variations within the coal zone as revealed by the well log. Anomalies in the seismic data are interpreted to indicate structural deformation and changes in coal properties. The study demonstrates detailed geological interpretation of high-resolution seismic data over a shallow coal deposit.
Instrument to measure the bidirectional reflectanceajsatienza
This instrument measures the bidirectional reflectance distribution function (BRDF) of surfaces with the following properties:
1. It measures the BRDF for eight illumination angles from 0 to 65 degrees, three colors (475, 570, 658 nm), and over 100 selected viewing angles.
2. The viewing zenith angles range from 5 to 65 degrees, and the azimuth angles range from 0 to ±180 degrees relative to the illumination direction.
3. Tests show it can measure the BRDF of flat surfaces with a precision of 1-5% and an accuracy of 10% of the measured reflectance.
1) The document analyzes volume curvature attributes in seismic data to identify subtle faults and fractures in a carbonate reservoir.
2) Volume curvature attributes, such as most positive and most negative, were better able to illuminate discontinuities and flexures associated with fracture zones and minor faults not evident in other seismic attributes or manual interpretation.
3) The identified lineaments from curvature attributes correlated with zones of high fracture density observed in well data, suggesting they could delineate faults with offsets below seismic resolution.
Borehole breakouts and insitu rock stressrana ammad
This document provides a review of borehole breakouts and their use as indicators of in-situ rock stress. It discusses how breakouts form as a result of spalling parallel to the minimum horizontal stress during drilling. Breakout analysis can provide information on stress orientation important for reservoir applications like well placement, production strategies, and hydraulic fracturing. It also discusses uses for drilling, crustal stress studies, rock mechanics, and outlines the history of understanding breakouts as stress indicators. The document reviews methods for identifying breakouts using tools like dipmeters and borehole imaging and debates using breakout geometry to estimate stress magnitudes.
Prediction Of Ground Settlement Response To Sheet Pile Extraction (P. Mc Gough)pmcgough
This paper presents a new empirical method for predicting ground surface settlement in response to sheet pile extraction. The method is based on field measurement data from several projects in Perth, Western Australia involving the extraction of sheet piles installed in sandy and soft clay soils. A design procedure is proposed that relates the predicted settlement profile to factors such as the sheet pile cross-section, depth, soil type, and amount of soil volume replaced after extraction. The method is shown to correlate well with limited published data on this topic. The effect of soil type on an "adhesion factor" used in the predictions is also examined.
Evaluation of Structural Geology of Jabal OmarIJERD Editor
The proposed Jabal Omar Development project includes several multi-storey buildings, roads, bridges and below ground structures. Dykes and joints are the most common geological features in the area; they vary in thickness and orientation. The spacing between adjacent discontinuities largely control the size of individual blocks of rock masses which govern the stability of rock structures. The shearing and faulting system normally associated with tectonic movement making the area very weak, highly weathered and unstable. All Structural geological units analyzed using stereographic projection
Lateral resolution and lithological interpretation of surface wave profi lingAdam O'Neill
This document summarizes research on using surface wave profiling to characterize near-surface geology. It discusses issues with lateral resolution when imaging subsurface features like sinkholes. Numerical modeling of a sinkhole in buried hard rock shows that wider sinkholes are resolved better than narrow ones. Field data from Western Australia that combines surface wave and electrical resistivity data illustrates improved lithological interpretation when both methods are used. The researchers investigate ways to enhance lateral resolution, such as using non-linear geophone spacing. They also demonstrate data-driven classification of rock types based on resistivity and shear wave velocity measurements.
The document discusses rock mass properties and the Hoek-Brown failure criterion for estimating the strength of jointed rock masses. It presents the generalized Hoek-Brown criterion equation and describes how to determine the intact rock properties of uniaxial compressive strength (σci) and the Hoek-Brown constant (mi) from triaxial test data or estimates. It also discusses estimating the Geological Strength Index (GSI) of the rock mass.
This document summarizes a seismic study of a coal deposit in Wabamun, Alberta. It provides background on the study area and coal deposit geology. It then describes the acquisition and processing of seismic reflection data from two lines over the deposit. The data is analyzed and interpreted, with control from a well. On one line, variations in the seismic character of the coal reflection are correlated to stratigraphic variations within the coal zone as revealed by the well log. Anomalies in the seismic data are interpreted to indicate structural deformation and changes in coal properties. The study demonstrates detailed geological interpretation of high-resolution seismic data over a shallow coal deposit.
Instrument to measure the bidirectional reflectanceajsatienza
This instrument measures the bidirectional reflectance distribution function (BRDF) of surfaces with the following properties:
1. It measures the BRDF for eight illumination angles from 0 to 65 degrees, three colors (475, 570, 658 nm), and over 100 selected viewing angles.
2. The viewing zenith angles range from 5 to 65 degrees, and the azimuth angles range from 0 to ±180 degrees relative to the illumination direction.
3. Tests show it can measure the BRDF of flat surfaces with a precision of 1-5% and an accuracy of 10% of the measured reflectance.
This document presents revisions to the Hoek-Brown failure criterion for rock masses. It resolves uncertainties in applying the criterion and incorporating it into numerical models. The revised criterion sets out a recommended calculation sequence and defines equations to determine rock mass strength parameters like cohesive strength and friction angle from the Geological Strength Index rating of rock mass quality. It also distinguishes between undisturbed and disturbed rock masses using a new disturbance factor.
1) The document describes small-scale graben (extensional faults) discovered on the Moon using images from the Lunar Reconnaissance Orbiter Camera.
2) Some graben are located near lobate scarps (contractional faults), while others are found in mare basalts and in the highlands.
3) The graben crosscut small impact craters, suggesting they formed recently, within the last 50 million years. This indicates the Moon has experienced recent extensional tectonic activity.
This document examines four Venusian shield fields through geological mapping using Synthetic Aperture Radar imagery. It finds that each field displays a distinct morphology, possibly related to differences in magma properties or eruption styles. Mapping allowed trends in shield morphologies to be recorded across different areas of Venus' surface. However, due to the resolution of imagery, establishing detailed stratigraphy within individual fields is challenging.
1) Rock bursts occur due to the violent release of strain energy stored in rock mass in underground excavations under high stress. They can be caused by stress redistribution around excavations or reactivation of geological discontinuities.
2) There are several types of rock bursts including strain bursts caused by buckling near excavation boundaries, pillar bursts due to pillar failure, and fault slips or shear ruptures related to geological structures.
3) Damage from rock bursts can range from limited ejection of small rock pieces to severe damage over a large area from higher energy events involving faults or shear ruptures. Prevention methods aim to reduce rock stiffness, dissipate strain energy, or modify excavation layouts and shapes to
The document analyzes differences in fractal dimension (D) and b-value between locked and creeping sections of the San Andreas Fault near Parkfield, California. It finds that in the locked section, D is between 0.96-1.14 and b is between 0.5-0.7, while in the creeping section, D is between 1.45-1.72 and b is between 1.1-1.6. However, the spatial distribution of hypocenters in the creeping section is not well approximated by a fractal distribution. The relationship between D and b is explored based on properties of the Parkfield fault.
The document describes a simulation study that assesses the effects of topography on polarimetric synthetic aperture radar (PolSAR) classification of forests and crops. A Scots pine forest scene was simulated with varying ground slopes and tree architectures. Polarimetric descriptors like orientation angle, alpha angle, and correlations were analyzed. Results showed that both range and azimuth slopes reduced double bounce scattering and changed polarimetric characteristics even after orientation compensation. Major forest scattering components were identified as direct forest scattering and ground-forest interactions.
The document describes a simulation study that assesses the effects of topography on polarimetric synthetic aperture radar (PolSAR) classification of forests and crops. A Scots pine forest scene was simulated with varying ground slopes and tree architectures. Polarimetric descriptors like orientation angle, alpha angle, and correlations were analyzed. Results showed that both range and azimuth slopes reduced double bounce scattering and changed scattering characteristics even after orientation compensation. Major forest scattering components were identified as direct forest scattering and ground-forest interactions.
The document summarizes scaling laws observed for geological faults. It finds that fault displacement scales linearly with fault length over 7 orders of magnitude, with a proportionality constant of around 10-2. Faults propagate through the formation of brittle process zones of microcracks around the fault tips. The width of these process zones increases linearly with fault length. These observations are consistent with an elastic-plastic crack model where fracture energy increases linearly with fault length. Similar scaling laws apply to earthquakes and other fractures in rock.
openings design in underground mines, different approaches, kirscha formulae for circular opening, plastic xzone effect on stability of opening, radial and tangential stresses distribution
Structural And Metamorphic Evolution Of The Melur Migmatites, In Melur Regio...inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
1. The document discusses using seismicity data and geodetic strain measurements from GPS to develop integrated seismic hazard models for western Turkey and the eastern Mediterranean.
2. Statistical analysis of earthquake catalog data shows relationships between seismic clustering, b-values, and geodetic measurements of shear and dilatation strains across different scales.
3. The results provide insights into how seismicity varies with tectonic setting and stress conditions, which can help identify areas of increased seismic risk.
The document discusses various geophysical investigation methods used in soil investigations, including seismic refraction and reflection surveys, resistivity surveys, and electromagnetic induction. It provides details on how each method works, including generating and measuring seismic waves or electrical currents and voltages in the ground to infer properties of subsurface soil and rock layers. Advantages are that the methods provide continuous subsurface profiles quickly and non-invasively over large areas. Examples of applications given include mapping bedrock, faults, and contaminant plumes.
Detection of Low-Speed Layer (Lvl) In Seismic Refraction Survey Using Combine...iosrjce
A combination of two geophysical methods not only helps to enhance the accuracy of results but also
helps to detect the presence of a low velocity layer which cannot be detected by refraction shooting alone. The
Direct Current resistivity method was combined with the seismic refraction method to infer the lithology of
Nnodo (Latitude 6.300
- 6.320N and Longitude 8.100
- 8.120E), Nigeria, during which a low-velocity layer was
encountered. The major instruments used were the signal enhancement seismograph and the ABEM terrameter.
The seismic refraction method revealed three layers of the earth from its surface with velocities 300m/s,
1200m/s and 2100m/s which were interpreted as dry/loose sand, saturated sand and limestone respectively. The
resistivity method however, revealed five geoelectric layers with resistivity values 957 Ωm,363 Ωm,1033
Ωm,489 Ωm and 135 Ωm which were interpreted as dry soil, saturated sand, sandy clay, limestone and shale
respectively. A comparison of the two results showed that the third layer from the surface at Nnodo interpreted
as probably sandy clay( from the resistivity survey) was not detected in the seismic refraction survey. This was
suspected to be a low-velocity layer with a velocity of about 600m/s. Hence the layer of limestone according to
the seismic result is the fourth layer of the study area and not the third.The actual lithology of the third layer
which the seismic refraction method could not detect is sandy clay. This was evident from the resistivity result.
The lithologic sequence of the study area from the earth’s surface is therefore dry soil, saturated sand, sandy
clay, limestone and fractured shale(wet).
This document provides a summary of Gil A. Anibal's presentation on analyzing 3D seismic attributes and well data. The presentation compares seismic attributes on horizons and phantom horizons at depths of 1108ms-1733ms and 1460ms-1733ms. Attributes like RMS, shale indicator, thin bed indicator, and spectral decomposition help enhance geological features and identify lithofacies changes, indicating sand-filled stream channels. The analysis aids interpretation of turbidite deposition and identifies potential zones of clean sands.
Infilled Frame and Soft Story behavior of L-Shaped Plain Irregular Building U...IRJET Journal
This document analyzes the behavior of L-shaped irregular buildings under earthquake loading. It models a G+9 story building with different configurations - bare frame, infilled frame, and infilled frame with a soft story at the ground level. The models are analyzed using ETABS software. The results show that as the plan irregularity increases, the eccentricity, displacement, drift and period also increase. For example, the maximum displacement along the Y direction for model L5 is over 2 times that of the regular model L0. In general, increasing plan irregularity leads to higher seismic effects. Infilled frames and those with soft stories experience greater drifts compared to bare frames.
This document discusses modeling the dynamic break in underground ring blasting operations. It presents a 3D visualization method using a Kleine field to model the potential break zone around blastholes, which can be used with cavity monitoring surveys to assess dilution and recovery. It examines circular and elliptical break geometries. The document also discusses challenges with underground blasting patterns and powder factors due to complex geometries and the confined nature of drilling. It explores methods for more accurately representing blast energy distribution and break using geometric shapes instead of just powder factor calculations.
The document summarizes findings from images and data collected by the Lunar Reconnaissance Orbiter regarding the Compton-Belkovich thorium anomaly on the lunar farside. Key findings include:
1) A central feature covering 25 by 35 km is identified, characterized by elevated topography and relatively high reflectance, including several volcanic domes from less than 1 km to over 6 km across.
2) Arcuate to irregular circular depressions observed are interpreted as collapse features associated with volcanism.
3) Spectral data finds the volcanic feature enriched in silica or alkali-feldspar, indicative of compositionally evolved, rhyolitic volcanic materials.
4)
This document summarizes a paper on modeling seismic anisotropy in fractured rock. It introduces a method to calculate the effective elastic properties of rock containing multiple sets of fractures by representing each fracture set with a compliance tensor. For a single set of parallel, rotationally symmetric fractures, the fracture compliance tensor depends on two parameters - the normal and tangential compliance. This allows fractures to be incorporated by adding their compliance tensors to the background rock compliance tensor. The result can be orthorhombic anisotropy even if the background is isotropic. An example is given of vertical fractures, where the method correctly produces a diagonal excess compliance tensor.
Mohr circle mohr circle anaysisand applicationShivam Jain
Mohr's circle is a graphical representation used to analyze the state of stress at a point. It relates the normal and shear stresses acting on planes of all orientations passing through that point. The document discusses how to construct Mohr's circle through an example and how it can be used to analyze principal stresses, maximum shear stress, and normal and shear stresses on any given plane. Applications of Mohr's circle include analyzing brittle and ductile deformation, the effects of pore pressure, and detecting stability in structures like bridges, dams, and slopes.
Charles R. Singer - Syn-rifting in the Lower JurassicCharlie Singer
This document summarizes research on Lower Jurassic carbonate deposits in western Sardinia that provide evidence of syn-sedimentary faulting during an extensional tectonic period. Fieldwork at a quarry exposure revealed a series of NE-dipping listric normal faults that caused lateral thickness variations and erosional intersections of marker horizons within the rotated fault blocks. Structural analysis indicated a SE-directed extensional stress regime prior to later block rotation. The faults interacted with deposition of shallow marine carbonate tempestite facies, providing constraints on the temporal and spatial extent of Mesozoic rifting in the region.
This document presents revisions to the Hoek-Brown failure criterion for rock masses. It resolves uncertainties in applying the criterion and incorporating it into numerical models. The revised criterion sets out a recommended calculation sequence and defines equations to determine rock mass strength parameters like cohesive strength and friction angle from the Geological Strength Index rating of rock mass quality. It also distinguishes between undisturbed and disturbed rock masses using a new disturbance factor.
1) The document describes small-scale graben (extensional faults) discovered on the Moon using images from the Lunar Reconnaissance Orbiter Camera.
2) Some graben are located near lobate scarps (contractional faults), while others are found in mare basalts and in the highlands.
3) The graben crosscut small impact craters, suggesting they formed recently, within the last 50 million years. This indicates the Moon has experienced recent extensional tectonic activity.
This document examines four Venusian shield fields through geological mapping using Synthetic Aperture Radar imagery. It finds that each field displays a distinct morphology, possibly related to differences in magma properties or eruption styles. Mapping allowed trends in shield morphologies to be recorded across different areas of Venus' surface. However, due to the resolution of imagery, establishing detailed stratigraphy within individual fields is challenging.
1) Rock bursts occur due to the violent release of strain energy stored in rock mass in underground excavations under high stress. They can be caused by stress redistribution around excavations or reactivation of geological discontinuities.
2) There are several types of rock bursts including strain bursts caused by buckling near excavation boundaries, pillar bursts due to pillar failure, and fault slips or shear ruptures related to geological structures.
3) Damage from rock bursts can range from limited ejection of small rock pieces to severe damage over a large area from higher energy events involving faults or shear ruptures. Prevention methods aim to reduce rock stiffness, dissipate strain energy, or modify excavation layouts and shapes to
The document analyzes differences in fractal dimension (D) and b-value between locked and creeping sections of the San Andreas Fault near Parkfield, California. It finds that in the locked section, D is between 0.96-1.14 and b is between 0.5-0.7, while in the creeping section, D is between 1.45-1.72 and b is between 1.1-1.6. However, the spatial distribution of hypocenters in the creeping section is not well approximated by a fractal distribution. The relationship between D and b is explored based on properties of the Parkfield fault.
The document describes a simulation study that assesses the effects of topography on polarimetric synthetic aperture radar (PolSAR) classification of forests and crops. A Scots pine forest scene was simulated with varying ground slopes and tree architectures. Polarimetric descriptors like orientation angle, alpha angle, and correlations were analyzed. Results showed that both range and azimuth slopes reduced double bounce scattering and changed polarimetric characteristics even after orientation compensation. Major forest scattering components were identified as direct forest scattering and ground-forest interactions.
The document describes a simulation study that assesses the effects of topography on polarimetric synthetic aperture radar (PolSAR) classification of forests and crops. A Scots pine forest scene was simulated with varying ground slopes and tree architectures. Polarimetric descriptors like orientation angle, alpha angle, and correlations were analyzed. Results showed that both range and azimuth slopes reduced double bounce scattering and changed scattering characteristics even after orientation compensation. Major forest scattering components were identified as direct forest scattering and ground-forest interactions.
The document summarizes scaling laws observed for geological faults. It finds that fault displacement scales linearly with fault length over 7 orders of magnitude, with a proportionality constant of around 10-2. Faults propagate through the formation of brittle process zones of microcracks around the fault tips. The width of these process zones increases linearly with fault length. These observations are consistent with an elastic-plastic crack model where fracture energy increases linearly with fault length. Similar scaling laws apply to earthquakes and other fractures in rock.
openings design in underground mines, different approaches, kirscha formulae for circular opening, plastic xzone effect on stability of opening, radial and tangential stresses distribution
Structural And Metamorphic Evolution Of The Melur Migmatites, In Melur Regio...inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
1. The document discusses using seismicity data and geodetic strain measurements from GPS to develop integrated seismic hazard models for western Turkey and the eastern Mediterranean.
2. Statistical analysis of earthquake catalog data shows relationships between seismic clustering, b-values, and geodetic measurements of shear and dilatation strains across different scales.
3. The results provide insights into how seismicity varies with tectonic setting and stress conditions, which can help identify areas of increased seismic risk.
The document discusses various geophysical investigation methods used in soil investigations, including seismic refraction and reflection surveys, resistivity surveys, and electromagnetic induction. It provides details on how each method works, including generating and measuring seismic waves or electrical currents and voltages in the ground to infer properties of subsurface soil and rock layers. Advantages are that the methods provide continuous subsurface profiles quickly and non-invasively over large areas. Examples of applications given include mapping bedrock, faults, and contaminant plumes.
Detection of Low-Speed Layer (Lvl) In Seismic Refraction Survey Using Combine...iosrjce
A combination of two geophysical methods not only helps to enhance the accuracy of results but also
helps to detect the presence of a low velocity layer which cannot be detected by refraction shooting alone. The
Direct Current resistivity method was combined with the seismic refraction method to infer the lithology of
Nnodo (Latitude 6.300
- 6.320N and Longitude 8.100
- 8.120E), Nigeria, during which a low-velocity layer was
encountered. The major instruments used were the signal enhancement seismograph and the ABEM terrameter.
The seismic refraction method revealed three layers of the earth from its surface with velocities 300m/s,
1200m/s and 2100m/s which were interpreted as dry/loose sand, saturated sand and limestone respectively. The
resistivity method however, revealed five geoelectric layers with resistivity values 957 Ωm,363 Ωm,1033
Ωm,489 Ωm and 135 Ωm which were interpreted as dry soil, saturated sand, sandy clay, limestone and shale
respectively. A comparison of the two results showed that the third layer from the surface at Nnodo interpreted
as probably sandy clay( from the resistivity survey) was not detected in the seismic refraction survey. This was
suspected to be a low-velocity layer with a velocity of about 600m/s. Hence the layer of limestone according to
the seismic result is the fourth layer of the study area and not the third.The actual lithology of the third layer
which the seismic refraction method could not detect is sandy clay. This was evident from the resistivity result.
The lithologic sequence of the study area from the earth’s surface is therefore dry soil, saturated sand, sandy
clay, limestone and fractured shale(wet).
This document provides a summary of Gil A. Anibal's presentation on analyzing 3D seismic attributes and well data. The presentation compares seismic attributes on horizons and phantom horizons at depths of 1108ms-1733ms and 1460ms-1733ms. Attributes like RMS, shale indicator, thin bed indicator, and spectral decomposition help enhance geological features and identify lithofacies changes, indicating sand-filled stream channels. The analysis aids interpretation of turbidite deposition and identifies potential zones of clean sands.
Infilled Frame and Soft Story behavior of L-Shaped Plain Irregular Building U...IRJET Journal
This document analyzes the behavior of L-shaped irregular buildings under earthquake loading. It models a G+9 story building with different configurations - bare frame, infilled frame, and infilled frame with a soft story at the ground level. The models are analyzed using ETABS software. The results show that as the plan irregularity increases, the eccentricity, displacement, drift and period also increase. For example, the maximum displacement along the Y direction for model L5 is over 2 times that of the regular model L0. In general, increasing plan irregularity leads to higher seismic effects. Infilled frames and those with soft stories experience greater drifts compared to bare frames.
This document discusses modeling the dynamic break in underground ring blasting operations. It presents a 3D visualization method using a Kleine field to model the potential break zone around blastholes, which can be used with cavity monitoring surveys to assess dilution and recovery. It examines circular and elliptical break geometries. The document also discusses challenges with underground blasting patterns and powder factors due to complex geometries and the confined nature of drilling. It explores methods for more accurately representing blast energy distribution and break using geometric shapes instead of just powder factor calculations.
The document summarizes findings from images and data collected by the Lunar Reconnaissance Orbiter regarding the Compton-Belkovich thorium anomaly on the lunar farside. Key findings include:
1) A central feature covering 25 by 35 km is identified, characterized by elevated topography and relatively high reflectance, including several volcanic domes from less than 1 km to over 6 km across.
2) Arcuate to irregular circular depressions observed are interpreted as collapse features associated with volcanism.
3) Spectral data finds the volcanic feature enriched in silica or alkali-feldspar, indicative of compositionally evolved, rhyolitic volcanic materials.
4)
This document summarizes a paper on modeling seismic anisotropy in fractured rock. It introduces a method to calculate the effective elastic properties of rock containing multiple sets of fractures by representing each fracture set with a compliance tensor. For a single set of parallel, rotationally symmetric fractures, the fracture compliance tensor depends on two parameters - the normal and tangential compliance. This allows fractures to be incorporated by adding their compliance tensors to the background rock compliance tensor. The result can be orthorhombic anisotropy even if the background is isotropic. An example is given of vertical fractures, where the method correctly produces a diagonal excess compliance tensor.
Mohr circle mohr circle anaysisand applicationShivam Jain
Mohr's circle is a graphical representation used to analyze the state of stress at a point. It relates the normal and shear stresses acting on planes of all orientations passing through that point. The document discusses how to construct Mohr's circle through an example and how it can be used to analyze principal stresses, maximum shear stress, and normal and shear stresses on any given plane. Applications of Mohr's circle include analyzing brittle and ductile deformation, the effects of pore pressure, and detecting stability in structures like bridges, dams, and slopes.
Charles R. Singer - Syn-rifting in the Lower JurassicCharlie Singer
This document summarizes research on Lower Jurassic carbonate deposits in western Sardinia that provide evidence of syn-sedimentary faulting during an extensional tectonic period. Fieldwork at a quarry exposure revealed a series of NE-dipping listric normal faults that caused lateral thickness variations and erosional intersections of marker horizons within the rotated fault blocks. Structural analysis indicated a SE-directed extensional stress regime prior to later block rotation. The faults interacted with deposition of shallow marine carbonate tempestite facies, providing constraints on the temporal and spatial extent of Mesozoic rifting in the region.
1995 mechanism of the step flow to island growth transition during mbe on si(...pmloscholte
The document discusses the transition between step flow and island growth during molecular beam epitaxy of silicon on a silicon (001) surface with dimer rows. It finds that:
1) For typical experimental conditions, diffusion perpendicular to the dimer rows cannot be neglected and a transition occurs from effectively 1D to 2D diffusion as the terrace width increases.
2) When including 2D diffusion, the critical flux for the step flow to island growth transition scales as the terrace width to the -4th power for large terraces, but as the terrace width to the -3rd power for small terraces.
3) Comparing to experimental data, accounting for diffusion perpendicular to the dimer rows is essential
Presentation given by Bertrand VIALA at NIHA Ankara to Undergrad students of Bilkent University
What does the Reverse Innovation theory tell us about business entry strategies in emerging markets
1998 growth pyramids on si(111) facets a cvd and mbe studypmloscholte
1) The morphology of growth pyramids formed on Si(111) facets during CVD growth was studied using atomic force microscopy.
2) Spiral and concentric step edge patterns were observed on the pyramid tops, indicating the pyramids originated from different types of dislocations.
3) The step edge patterns and sharp corners suggest growth during CVD is governed by step edge processes and surface diffusion is not rate limiting.
1996 strain in nanoscale germanium hut clusters on si(001) studied by x ray d...pmloscholte
This document summarizes a study that used x-ray diffraction and scanning tunneling microscopy to investigate the strain in nanoscale germanium hut clusters on silicon substrates. The key findings are:
1) X-ray diffraction measurements revealed contributions from the hut clusters that allowed determining the strain distribution uniquely from the clusters.
2) The germanium clusters are almost fully strained with 0.5% misfit at the interface but strain is relaxed towards the apex, with 4.2% misfit indicating the natural germanium lattice spacing.
3) By modeling the asymmetric intensity distributions around diffraction peaks, the study determined that strain is relaxed uniformly through the hut clusters from a maximum near the interface to a minimum
1997 nucleation of homoepitaxial si chains on si(001) at room temperaturepmloscholte
1) Si dimers initially adsorb at preferred sites on the Si(001) surface, with most occupying C-positions.
2) Interactions between dimers and diffusing adatoms lead to the formation of three-atom clusters like twins and crosses. These can extend into diluted lines of C dimers along [110] and [310] directions.
3) Upon further deposition, the diluted dimer lines transform into epitaxial dimer rows through a process starting at the line ends of reorienting dimers and adding mobile adatoms.
1997 atomic details of step flow growth on si(001)pmloscholte
1. The study uses scanning tunneling microscopy to observe atomic details of step flow growth on the Si(001) surface at the single adatom level.
2. Empty state images clearly show single adatoms bound to step edges, revealing stable binding sites. Subsequent addition of adatoms forms different step edge configurations.
3. Dynamic processes are also observed, including adatom diffusion along step edges between stable binding sites and dimer formation between two adatoms.
4. Different step edge configurations are stable and can serve as sites for other processes, such as creating single dimer vacancies, providing insight into growth mechanisms.
1998 epitaxial film growth of the charge density-wave conductor rb0.30 moo3 o...pmloscholte
1) Thin films of the charge density wave compound Rb0.30MoO3 were grown on SrTiO3 (001) substrates using pulsed laser deposition.
2) Initial growth proceeds through the formation of uniform, droplet-shaped islands that are fully relaxed. Thicker films form larger clusters that differ in size and have asymmetric shapes with clear facets.
3) X-ray diffraction shows the films have a preferred out-of-plane growth direction and four in-plane orientations corresponding to the symmetry of the SrTiO3 substrate. The correlation length perpendicular to the charge density wave axis is smaller than the dimensions of the grain clusters in thicker films.
1996 atomic force microscopy study of (001) sr tio3 surfacespmloscholte
The document summarizes an atomic force microscopy study of SrTiO3 surfaces after different heat treatments. The key points are:
1) Annealing in O3 results in atomically flat terraces separated by smooth, one unit cell high steps that follow the substrate's miscut orientation.
2) Annealing in O2 produces irregularly shaped terraces with step heights varying between 0.5-2.5 unit cells. Line defects and holes are also observed.
3) Depositing SrTiO3 on a surface annealed in O3 increases roughness due to island formation but heals line defects.
4) Annealing in UHV produces rougher steps and surface clusters, indicating a
Specimens of the Nairobi phonolites, of lower tertiary age dated at 5.2 my, from four sites were sampled and treated in alternating field up to 100mT, stable primary components of the natural remanence isolated and various magnetic parameters analyzed. The cleaned mean directions have been classified as intermediate or reversed. The mean direction and corresponding pole position of the phonolites, for the intermediately magnetized sites is calculated at declination D=251.0o , inclination I=0.1 o and longitude 126.49 o E, latitude 18.9 o S and for the reversedly magnetized sites at D=169.6o , I=2.5 o ( α95=9.6o ) and 127.3o E, 79.6o S with errors (δm=9.6 o , δp=4.8o ) , respectively. These results may assist in stratigraphic correlation of Nairobi area rocks
1. The document discusses applying multi-curve reconstruction technology to seismic inversion to improve accuracy and reliability. It focuses on reconstructing SP and RMN curves from well logs that are affected by various distortions.
2. The process of reconstructing the curves involves removing baseline drift, standardizing values, applying linear filtering, and fitting the curves. This removes interference and retains valid lithological information.
3. Reconstructing high quality curves improves the resolution and credibility of seismic inversion results. The method is shown to effectively predict sand distribution with little error.
This document presents an analytical solution for analyzing the vibration of machine foundations resting on layered soil. It uses a cone model approach to determine dynamic stiffness and damping coefficients for a rigid, massless circular foundation on a soil layer underlain by a rigid base subjected to torsional harmonic excitation. The cone model concept models the soil as truncated cones that allow analyzing wave propagation. Equations are developed relating the rotational displacement of the foundation to the dynamic impedance functions using the cone model approach. Parametric analyses are then performed to understand the effect of soil layer depth, damping ratio, and Poisson's ratio on the frequency-amplitude response of the foundation.
Reflective high energy electron diffractionOleg Maksimov
This document discusses Reflective High-Energy Electron Diffraction (RHEED), a technique used to characterize thin films in-situ during deposition. RHEED works by directing a high-energy electron beam at the substrate surface at a low angle. The diffracted beam provides information on the film's crystalline structure and surface morphology. RHEED patterns indicate whether a film is single crystalline, polycrystalline, or textured. Oscillations in the RHEED intensity during growth also allow real-time measurement of deposition rates. Advances now enable RHEED to be used at higher pressures, making it suitable for characterizing a wider range of deposition methods.
Ultra smooth and lattice relaxed zn o thin films [eid]Eid Elsayed
The crystal structure and quality of ZnO thin films were enhanced by high temperature vacuum annealing. 150 nm thick ZnO films were deposited on a-plane sapphire substrates by RF sputtering at 600°C and then annealed in situ at temperatures from 700°C to 900°C. Higher annealing temperatures produced smoother films with root mean square roughness reaching 0.3 nm at 850°C. Raman spectroscopy showed the A1(TO) mode at all annealing temperatures and the A1(LO) mode appeared above 800°C, indicating improved crystal quality. X-ray diffraction revealed narrower diffraction peaks and a relaxed lattice constant matching bulk ZnO at 900°C annealing, demonstrating high quality c-axis oriented epit
Rosa alejandra lukaszew tests of the gurenvich odel toward larger field gra...thinfilmsworkshop
SRF properties are inherently a surface phenomenon involving a material thickness of a few microns thus opening up the possibility of using thin film coatings to achieve a desired performance. I will describe our experimental attempts to test the superconducting/insulating/superconducting (SIS) multilayer model proposed by A. Gurevich [1] to shield the bulk of the cavity from vortex penetration and hence enable larger accelerating fields than presently possible.
This report summarizes a computational simulation of the solidification behavior of a eutectic system in response to changes in pulling velocity. A phase field model was developed to simulate the solidification dynamics when increasing or decreasing the pulling velocity of a thin succinonitrile–(D)camphor film. The model was improved by increasing the domain size to include multiple alternating layers, adding a function to change the pulling velocity during solidification, and utilizing a shift function to increase computational efficiency. Simulation results showed changes in lamellar spacing and solidification behavior consistent with experimental observations of a similar system when increasing or decreasing the pulling velocity.
Detection of visible light from the darkest worldSérgio Sacani
This document reports the detection of visible light from the exoplanet TrES-2b using Kepler photometry data. The analysis finds a day-night contrast amplitude of 6.5 ± 1.9 parts per million, representing the lowest amplitude orbital phase variation discovered. This signal is detected at a confidence level of 99.98% and persists across different models of the data, appearing robust. If interpreted as scattering, it corresponds to a geometric albedo of 0.0253±0.0072 for TrES-2b, making it the darkest exoplanet detected so far. However, models indicate significant day-side emission, implying an even lower true albedo.
Morphological characterization of Brazilian organ clays using AFM and SEM stu...IJMER
This study used SEM and AFM techniques to characterize the morphology of Brazilian montmorillonites before and after intercalation with organic compounds. AFM revealed layered structures with smooth basal planes and irregular edges on the bare clay minerals. The intercalated samples had smoother surfaces with less adhesion forces. SEM showed a continuous surface with small, irregular particles. The combination of techniques provided insight into the poor crystallinity of the Brazilian montmorillonites and how intercalation changes their surface properties.
This document summarizes simulations of graphene growth on a copper substrate. Monte Carlo simulations were performed on a honeycomb lattice with various levels of static and dynamic substrate disorder. For static disorder, carbon atoms reside on favorable substrate sites, reducing mobility and resulting in smaller islands. For dynamic disorder, the changing substrate allows islands to move and reform, enhancing island size at optimal temperatures. The substrate itself shows no ordering without carbon islands at high dynamic disorder temperatures.
This document summarizes research on the microstructure and damage initiation in a duplex stainless steel. Electron backscatter diffraction was used to correlate the local phase morphology with crystallographic properties. In situ tensile tests were performed to characterize strain fields and observe sites of damage nucleation. Damage was found to nucleate near stress concentrations rather than in highly deformed areas. Finite element modeling accounted for the bicrystal morphology and anisotropic plasticity of phases. Damage initiation was correlated with local crystallographic orientations and common slip systems between phases.
The document analyzes the correlations between microstructure, intrinsic magnetization switching properties, and recording performance in exchange-coupled composite media. It finds that thickening the hard magnetic layer or NiW seed layers decreases the intrinsic coercive squareness parameter Sint, while thickening the soft layer initially increases Sint sharply and then slightly. Changes in Sint and the extent of incoherent switching are correlated to microstructural features like grain size. Higher Sint values are also correlated with improved signal-to-noise ratio and worse adjacent track interference performance.
This document summarizes a study that performed broadband frequency simulations of strong ground motion in the Sea of Marmara region of Turkey based on fault rupture scenarios. Three earthquake scenarios were modeled involving rupture of the Central Marmara Fault and North Boundary Fault, which pose the largest hazard to Istanbul. A hybrid technique was used that combines deterministic and semi-stochastic methods. The location of the hypocenter was found to be a critical parameter for predicting ground motions in Istanbul. Anelasticity was also found to significantly affect regional attenuation of peak ground accelerations. The simulated ground motions resulted in large acceleration response spectra at long periods that could be critical for building damage in Istanbul during an actual earthquake.
The document summarizes research on using seismic methods to detect and characterize a sinkhole in Doha, Qatar. A seismic survey was conducted along the edge of the sinkhole opening. The recorded seismic data revealed a distinct resonance peak at 70 Hz above the sinkhole. Numerical modeling showed that this peak is indicative of a karst side wall separating rock, karst border, and roof. The data were inverted in the frequency domain and fit using a model with low velocity and density parameters in the sinkhole layer, representing the complex geometry of karst.
Similar to 1996 origin of rippled structures formed during growth of si on si(001) with mbe (20)
1998 epitaxial clusters studied by synchrotron x ray diffraction and scanning...pmloscholte
1) The document summarizes studies of three nanoscale cluster systems using synchrotron X-ray diffraction and scanning tunneling microscopy: Ge hut clusters on Si(001), In clusters on Ge(001) that form 103 facets, and wedge-shaped Cu clusters buried in Cu films on Ni(001).
2) X-ray diffraction is used to determine the fundamental structural properties of the clusters, such as strain relaxation, by measuring crystal truncation rods from the cluster facet planes.
3) For the Ge/Si system, diffraction data found strain relaxation of 0.5-4% within the hut clusters. For the In/Ge system, clusters were completely relaxed from the substrate with In atoms stabilizing the
1998 Appl. Phys. A 66 (1998), p857 design and construction of a high resoluti...pmloscholte
The document describes the design and construction of a high-resolution 3D translation stage for a scanning tunneling microscope (STM) equipped with a newly developed capacitive translation sensor. Key points:
1) The sensor can measure translations in the lateral and perpendicular directions with sub-angstrom resolution.
2) In combination with a model-based digital feedback system, the sensor and stage will enable accurate probe positioning and control, making the STM suitable for metrological applications.
3) The capacitive sensor can detect translations in three dimensions with resolutions of 30 picometers laterally and 10 picometers perpendicular to the surface.
1996 a calibrated scanning tunneling microscope equipped with capacitive sensorspmloscholte
1) A scanning tunneling microscope equipped with capacitive sensors has been developed to measure the real-time X-Y position and correct for errors caused by piezoelectric actuator properties like hysteresis and nonlinearity.
2) The microscope uses a calibrated scanning stage with capacitive sensors that measure the actual X-Y position and provide feedback to dynamically adjust the piezo voltages to reach the desired scanning positions with minimal error.
3) This allows surfaces to be scanned geometrically accurately while correcting for drift and low-frequency vibrations in real time.
1995 analysis of piezo actuators in translation constructionspmloscholte
1) A translation stage using piezo stacks as actuators was developed to generate displacements with nanometer accuracy over a dynamic range of 10 micrometers. Capacitive sensors were able to measure displacements with subnanometer resolution.
2) Using the high precision measurements from the capacitive sensors, the displacement properties of the piezo actuator in the translation stage could be characterized with great accuracy when different voltages were applied.
3) A model is presented to describe the general behavior of a piezo actuator in a translation stage, and the hysteresis behavior observed in the piezo actuator is found to have point symmetry properties and branches that can be described by third-order polynomials.
1999 observation of zero creep in piezoelectric actuatorspmloscholte
The document summarizes experiments on piezoelectric actuators that observe zero creep in certain locations of the hysteresis loop. Specifically:
1) Relaxation experiments using an offset sinusoidal voltage found relaxation increased hysteresis loop tilt but did not reduce hysteresis. Zero creep was observed at hysteresis loop extremum.
2) Creep experiments varying delay time also increased loop tilt but zero creep locations did not change and coincided with points where loop slope equaled virgin curve slope.
3) Increasing input voltage amplitude did not affect zero creep behavior or virgin curve slope. This characteristic was independent of experiments.
1994 restoration of noisy scanning tunneling microscope imagespmloscholte
This document compares and improves several implementations of the Wiener filter to remove noise from Scanning Tunneling Microscope (STM) images. It finds that the implementation by Weisman et al. using the noise model of Stoll et al. provides the best performance on both simulated and real STM images. It tests the filters on simulated graphite images with added 1/f noise and finds the modified Weisman filter performs significantly better than other implementations on a real STM graphite image due to deviations from the 1/f noise model.
2000 surface polymerization of epitaxial sb wires on si(001)pmloscholte
This document reports on a study of the local density of states of epitaxial antimony nanostructures on silicon 001 using scanning tunneling spectroscopy. The key findings are:
1) Epitaxial antimony lines self-assemble on the silicon surface when antimony is deposited at low rates and the sample is annealed. The lines are two atoms wide and extend up to 12 antimony dimers in length.
2) Spectroscopy shows the electronic structure in the center of the antimony lines is similar to the silicon surface, indicating the lines are nonmetallic. In contrast, the ends of the lines show a finite density of states at the Fermi level, consistent with theoretical predictions of a "radical
1998 characterisation of multilayers by x ray reflectionpmloscholte
This document presents a theoretical model for characterizing multilayers using X-ray reflection. The model includes refraction effects and describes diffuse scattering from multilayers with roughened interfaces, including islands and miscut-induced steps. The model calculates X-ray intensity profiles that can be compared to experimental data to deduce the morphology of interfaces, such as mean island size and average step height. The model is applied to experimental data from a Si/Ge multilayer and results in values consistent with AFM images.
1997 sodium doped dimer rows on si(001)pmloscholte
1) The stability and electronic structure of a sodium-doped silicon dimer row on the hydrogen-passivated Si(001) 2x1 surface is studied using first-principles calculations.
2) It is predicted that sodium atoms evaporated onto the surface will stick preferentially to the depassivated dimer row.
3) This leads to a partially filled empty one-dimensional state of the dimer row, making it metallic in character and behaving as a thin metallic nanowire of atomic dimensions.
1997 room temperature growth of submonolayers of silicon on si(001) studied w...pmloscholte
1) Room-temperature growth of submonolayers of silicon on Si(001) was studied using scanning tunneling microscopy (STM).
2) At low coverages, adatoms aggregate into dimers in different geometries (A, B, C, D). A kinetic model is proposed for dimer formation.
3) At higher coverages, dimers line up to form linear structures in the [110] and [310] directions. Near 0.2 ML coverage, these lines merge to form a random network that later converts into epitaxial dimer rows above 0.2 ML.
1996 new application of classical x ray diffraction methods for epitaxial fil...pmloscholte
This document describes a new method for using classical X-ray diffraction to characterize epitaxial thin films. The method combines powder diffraction data with a Weissenberg camera technique to provide a complete overview of the in-plane and out-of-plane characteristics of the film and its relationship to the substrate in just two scans. This includes information on the film's orientation, strain, texture, and lattice parameters relative to the substrate. The method is illustrated using several epitaxial film/substrate systems and provides structural information simply and reliably using standard laboratory X-ray equipment.
1996 interactions between adsorbed si dimers on si(001)pmloscholte
1) The interactions between adsorbed silicon dimers on a silicon 001 surface were studied using scanning tunneling microscopy.
2) It was found that by increasing the tip-sample voltage, transitions between clusters of dimers could be induced. These field-enhanced transitions allowed the interactions between dimers to be clarified.
3) Two dimers in a BB configuration were found to interact strongly, forming a faintly visible "twin" structure. In contrast, dimers in an AB configuration showed little interaction.
1995 growth mechanisms of coevaporated sm ba2cu3oy thin filmspmloscholte
The document discusses the benefits of exercise for mental health. Regular physical activity can help reduce anxiety and depression and improve mood and cognitive functioning. Exercise causes chemical changes in the brain that may help protect against mental illness and improve symptoms.
1994 the influence of dimerization on the stability of ge hutclusters on si(001)pmloscholte
1) The epitaxial growth of Ge on Si(001) initially proceeds two-dimensionally but then forms three-dimensional Ge nanocrystals called "hutclusters".
2) Hutclusters have well-defined, highly anisotropic shapes bounded by (105) facets, which is surprising since (105) facets are normally not stable for macroscopic crystals.
3) The paper presents a model to explain the stability and morphology of hutclusters, identifying the key parameters of strain from lattice mismatch, nanocrystal size, and surface energies of the substrate and nanocrystal facets.
1994 nucleation and growth of c parallel grains in co-evaporated sm ba2cu3oy ...pmloscholte
1) The study investigates the nucleation and growth of c-parallel (c//) grains in co-evaporated SmBa2Cu3Oy films using scanning tunneling microscopy, x-ray diffraction, and transmission electron microscopy.
2) It was found that the volume fraction of c// grains increases with increasing supersaturation during film growth, indicating that kinetic factors like reduced surface mobility promote c// nucleation over c-perpendicular growth.
3) No evidence was found of a critical thickness for a switch from c-perpendicular to c// growth; instead, c// grains nucleate throughout film growth when supersaturation is high.
1994 atomic structure of longitudinal sections of a pitch based carbon fiber ...pmloscholte
1) STM images of longitudinal sections of pitch-based carbon fibers revealed a hexagonal superstructure with a periodicity of 14.9 A, indicating the top graphitic plane was rotated 9.5" from the underlying bulk.
2) Near defects, this superstructure was modulated with a (6 x fi)R30" pattern. The same modulation was found in images showing atomic resolution.
3) Power spectra of modulated regions contained extra peaks corresponding to the (6 x fi)R30" pattern, in addition to the six peaks from the hexagonal graphitic structure. This indicates the atomic structure is disturbed to a depth of at least two layers from the surface.
1992 schottky barrier formation in conducting polymerspmloscholte
1. The authors studied thin films of poly(3-hexylthiophene) (PHT) and polypyrrole (PPY) on highly oriented pyrolytic graphite using scanning tunneling microscopy.
2. They observed semicrystalline order in the form of micro-islands connected by parallel polymer strands. The orientation of the strands is determined by the substrate.
3. For PPY films, they observed superhelical structures not previously reported. The apparent height of polymer strands was found to differ for positive and negative bias voltages, which the authors attribute to the formation of a Schottky barrier between the metallic tip and semiconducting polymer.
1992 asymmetrical dimers on the ge(001) 2 × 1-sb surface observed using x-ray...pmloscholte
The document summarizes a study that used x-ray diffraction to determine the atomic structure of the 2x1 reconstruction on the Ge(001) surface induced by antimony (Sb) adsorption. The key findings are:
1) Sb forms asymmetric dimers on the Ge(001) surface, replacing the symmetric Ge dimers, with a bond length of 2.90 Angstroms and a midpoint shift of 0.16 Angstroms.
2) This is the first reported asymmetric dimer structure for a group IV/V system, in contrast to the symmetric dimers typically observed for systems like As/Si(001).
3) Relaxations of the top four substrate layers were also measured and compared
1990 crystallization kinetics of thin amorphous in sb filmspmloscholte
1) Evaporated and sputtered InSb films have different crystallization properties. Evaporated films have a lower activation energy of 1.39 eV and crystallize by three-dimensional growth on existing nuclei.
2) Sputtered films have a higher activation energy of 2.7 eV and crystallize by nucleation and subsequent growth on the nuclei. The Avrami exponent indicates sputtered films require crystalline nuclei to form before crystallization can begin.
3) Transmission electron microscopy images show evaporated films have existing nuclei while sputtered films have no visible crystallites in the as-deposited state, requiring nucleation.
1989 optical measurement of the refractive index, layer thickness, and volume...pmloscholte
This document discusses a method for determining the complex refractive index, layer thickness, and volume changes of thin films using optical measurements. The method involves measuring reflectance and transmittance values across a range of intentionally varied layer thicknesses, rather than fitting those values as functions of independently measured thicknesses. The measurements provide information needed for optical recording applications. The complex refractive index, layer thicknesses, and volume changes can then be unambiguously calculated by fitting curves to the reflectance-transmittance plane measured across multiple thicknesses. An example application determines these properties for thin films of GaSb and InSb for use in optical recording.
How to Make a Field Mandatory in Odoo 17Celine George
In Odoo, making a field required can be done through both Python code and XML views. When you set the required attribute to True in Python code, it makes the field required across all views where it's used. Conversely, when you set the required attribute in XML views, it makes the field required only in the context of that particular view.
This presentation was provided by Steph Pollock of The American Psychological Association’s Journals Program, and Damita Snow, of The American Society of Civil Engineers (ASCE), for the initial session of NISO's 2024 Training Series "DEIA in the Scholarly Landscape." Session One: 'Setting Expectations: a DEIA Primer,' was held June 6, 2024.
This document provides an overview of wound healing, its functions, stages, mechanisms, factors affecting it, and complications.
A wound is a break in the integrity of the skin or tissues, which may be associated with disruption of the structure and function.
Healing is the body’s response to injury in an attempt to restore normal structure and functions.
Healing can occur in two ways: Regeneration and Repair
There are 4 phases of wound healing: hemostasis, inflammation, proliferation, and remodeling. This document also describes the mechanism of wound healing. Factors that affect healing include infection, uncontrolled diabetes, poor nutrition, age, anemia, the presence of foreign bodies, etc.
Complications of wound healing like infection, hyperpigmentation of scar, contractures, and keloid formation.
it describes the bony anatomy including the femoral head , acetabulum, labrum . also discusses the capsule , ligaments . muscle that act on the hip joint and the range of motion are outlined. factors affecting hip joint stability and weight transmission through the joint are summarized.
Walmart Business+ and Spark Good for Nonprofits.pdfTechSoup
"Learn about all the ways Walmart supports nonprofit organizations.
You will hear from Liz Willett, the Head of Nonprofits, and hear about what Walmart is doing to help nonprofits, including Walmart Business and Spark Good. Walmart Business+ is a new offer for nonprofits that offers discounts and also streamlines nonprofits order and expense tracking, saving time and money.
The webinar may also give some examples on how nonprofits can best leverage Walmart Business+.
The event will cover the following::
Walmart Business + (https://business.walmart.com/plus) is a new shopping experience for nonprofits, schools, and local business customers that connects an exclusive online shopping experience to stores. Benefits include free delivery and shipping, a 'Spend Analytics” feature, special discounts, deals and tax-exempt shopping.
Special TechSoup offer for a free 180 days membership, and up to $150 in discounts on eligible orders.
Spark Good (walmart.com/sparkgood) is a charitable platform that enables nonprofits to receive donations directly from customers and associates.
Answers about how you can do more with Walmart!"
Leveraging Generative AI to Drive Nonprofit InnovationTechSoup
In this webinar, participants learned how to utilize Generative AI to streamline operations and elevate member engagement. Amazon Web Service experts provided a customer specific use cases and dived into low/no-code tools that are quick and easy to deploy through Amazon Web Service (AWS.)
Strategies for Effective Upskilling is a presentation by Chinwendu Peace in a Your Skill Boost Masterclass organisation by the Excellence Foundation for South Sudan on 08th and 09th June 2024 from 1 PM to 3 PM on each day.
বাংলাদেশের অর্থনৈতিক সমীক্ষা ২০২৪ [Bangladesh Economic Review 2024 Bangla.pdf] কম্পিউটার , ট্যাব ও স্মার্ট ফোন ভার্সন সহ সম্পূর্ণ বাংলা ই-বুক বা pdf বই " সুচিপত্র ...বুকমার্ক মেনু 🔖 ও হাইপার লিংক মেনু 📝👆 যুক্ত ..
আমাদের সবার জন্য খুব খুব গুরুত্বপূর্ণ একটি বই ..বিসিএস, ব্যাংক, ইউনিভার্সিটি ভর্তি ও যে কোন প্রতিযোগিতা মূলক পরীক্ষার জন্য এর খুব ইম্পরট্যান্ট একটি বিষয় ...তাছাড়া বাংলাদেশের সাম্প্রতিক যে কোন ডাটা বা তথ্য এই বইতে পাবেন ...
তাই একজন নাগরিক হিসাবে এই তথ্য গুলো আপনার জানা প্রয়োজন ...।
বিসিএস ও ব্যাংক এর লিখিত পরীক্ষা ...+এছাড়া মাধ্যমিক ও উচ্চমাধ্যমিকের স্টুডেন্টদের জন্য অনেক কাজে আসবে ...
How to Setup Warehouse & Location in Odoo 17 InventoryCeline George
In this slide, we'll explore how to set up warehouses and locations in Odoo 17 Inventory. This will help us manage our stock effectively, track inventory levels, and streamline warehouse operations.
2. 642 J. van Wingerden et a l . / Surface Science 352-354 (1996) 641-645
In this paper we will first present new experimen- bonds of the lower terrace have to be broken for
tal evidence for the microscopic form of the steps on every other dimer attached to a kink site, stable
the rippled surface. Furthermore, we present a new growth units consist of two dimers. For step flow
model which shows that the inherent discreteness of growth no islands are formed on the terraces and
growth can cause the onset of ripple formation. growth proceeds via attachment of growth units to
the step edges, which occurs mainly at kink sites.
For surfaces with alternating S A and S B step edges
2. The Si(001) surface this causes a much higher growth rate at Ss step
edges so that they will catch up with the S n step
The atoms of the Si(001) surface top layer form edges.
dimers, which form rows in the (110) directions.
The orientation of the dimer rows rotates over 90
degrees at single atomic height steps. In Fig. 1 an 3. The microscopic ripple structure
STM image of the Si(001) surface is shown. We use
the notation of Chadi [3] for the S A and S B step In this section we present the results of measure-
edges, where the dimer rows of the upper terrace are ments, where atomic force microscopy, optical mi-
parallel and perpendicular to the step edges, respec- croscopy, and X-ray crystallography have been used
tively. to characterize the microscopic structure of the rip-
Because S A step edges have the lowest energy [3], ples. For these experiments a 2 /xm thick layer was
the introduction of kinks is energetically un- grown on Si(001) at 650°C with a rate of 1.4 .~/s.
favourable due to the accompanying small pieces of The vicinal angle of the sample (i.e. the angle be-
S B step edge. Therefore, S A step edges are relatively tween the macroscopic surface and the crystallo-
straight with a density of thermally excited kinks graphic surface) is determined to be 0.296 ___0.002 °.
which is in most cases much lower than the density The angle between the average step edge direction
of kinks enforced by the misorientation. On the other and the [110] direction is 20.3 ___0.4 °. The average
hand S B step edges are rough because of thermal ripple direction has been determined from Nomarski
excitation of kinks. If the step edge direction deter- microscope images (see Fig. 2a for a typical exam-
mined by the misorientation of the macroscopic sur- pie). By measuring the ripple orientation and the
face is close to the (110) direction, step edges are crystallographic [110] orientation relative to the sam-
alternating of the S A and S B type. Under growth ple holder, the angle between the ripple and the [110]
conditions adatoms as well as ad-dimers are mobile, orientation is determined to be 46 ___2 °. These orien-
and their diffusion is much faster along than perpen- tations are drawn in Fig. 2f.
dicular to the dimer rows [4,5]. Because two dimer AFM images of the rippled surface have been
obtained under atmospheric conditions because no in
situ scanning probe microscope is available in the
equipment where the thick Si layers are grown. A
large scan area AFM image is shown in Fig. 2b. The
cross section perpendicular to the ripple direction
(Fig. 2c) shows a ripple height of about 3 nm.
Although the native silicon oxide layer on top limits
the resolution, individual step edges are observed on
a small scan area (Fig. 2d) and on the corresponding
high pass filtered image (Fig. 2e). The orientations in
Fig. 2f are found by drawing the [110] direction and
the average step edge direction relative to the ripple
direction observed in the AFM image. By comparing
Fig. 1, STM image of Si(001) with Sn and S B step edge seg- these directions it is clear that the steps run approxi-
ments. mately in the [1 I0] direction in those regions where
3. J. oan Wingerden et aL / Surface Science 352-354 (1996) 641-645 643
+ + I0.0
+
?2 .....
0 215 s:o 715 10.0 12'.5
(a) 0 2,5 5.0 7.5 I0.0
o (c)
p.m
IT
0 1.0 2.0 3.0 ~m 0 1.0 2,0 3.0 ~m
Fig. 2. Nomarski microscope image (76 x 58 /xm 2) (a) and large scan area AFM image (b) with the corresponding cross section (c).
Individual step edges are observed in the AFM image (3.6 x 3.6 /zm 2) before (d) and after high pass filtering (e). A step edge and the
relevant directions are drawn schematically in (f).
individual steps are resolved (the bright areas in Fig.
2e). Furthermore, to obtain the average step edge - - [11
O]
direction corresponding to the vicinal orientation of
the surface, we need to assume that in those parts
where no individual step edges are resolved, the
steps should on the average run along the [~10]
direction. The fact that in these regions no steps are (a)
observed is caused by the limited resolution, possibly
in combination with a larger roughness of these step
segments. Thus, the macroscopically visible ripples
are not formed by the bunching of steps. Instead they
are caused by "kink bunching" in combination with
strong correlations in the fluctuations of neighbour-
ing steps. That strong correlations in the fluctuations
A ~ B (b)
of neighbouring steps lead to a rippled structure is
demonstrated in the schematic drawings in Fig. 3a Fig. 3. Schematic top view (a) and cross section (b) along the line
AB of a surface where ripples are formed because of the strong
and Fig. 3b. Straight SA segments are formed along
correlations in the fluctuations of neighbouring steps. Straight
[110]. Kink bunches are shown as straight lines along segments along R10] indicate kinkbunches with many kinks and
[110] although they need not necessarily be straight. not individual kinks.
4. 644 J. van Wingerden et aL / Surface Science 352-354 (1996) 641-645
Neighbouring steps exhibit similar bunches shifted unstable
over the same distance along the step edge. The
magnitude of this shift determines the ripple direc- iL~[11 o] (a)
tion. In the next section we discuss the onset of the
kinkbunching process in more detail. stable
I.._
L-.
= N120
4. Kink bunching ~1 O0
¢~ 80
• ~ 60
-u (b)
In thermodynamic equilibrium kinks are more or -~ 40
less uniformly distributed along the step edges. The
rippled surface will return to this situation if growth 0 2 4 6 8 10 12
x 1000 SA Layers
is stopped, while the sample remains at the growth
temperature [1]. In this section we propose a model [~t o]
that explains how during growth fluctuations in the
kink distribution increase in such a way that devia-
~100~) Growth Uni~ Lengths~
1o] (c)
tions on large length scales become dominant. Here,
we define a kink as the end of a single dimer row at Fig. 4. Removal of a growth unit at a kinkbuneh with 3 kinks
from an unstable to a stable configuration (a). The increase of the
an S A step edge.
standard deviation of the kink distribution during the simulated
The model is based on two assumptions. First of evolution of a single isolated step edge (b) with a typical example
all the discreteness of the growth process causes shot of a step edge profile after growth of 1000 SA layers (c). The
noise fluctuations in the number of growth units straight lines indicate the neighbouring steps.
attached to the kink sites. Therefore, the statistical
deviations of the kink sites from an equidistant dis-
tribution increase continuously during growth. How- will stick in the same kinkbunch to the first kink
ever, these deviations are uniformly distributed over which does not pass another one by adding the
all length scales. growth unit as shown in Fig. 4a. Using values corre-
The second assumption is that thermal equilib- sponding to the sample studied experimentally (see
rium is still maintained on short length scales. A Section 3) an average kink distance of 2.7 growth
growth unit will not stick at a kink site if the unit lengths is used and an average number of 197
resulting local geometry is energetically un- growth units have to stick to each kink site for every
favourable; i.e. if the growth unit has only one S A layer.
neighbouring growth unit in the (001) plane as de- Fig. 4b shows the increase: of the standard devia-
picted in Fig. 4a. tion of the kink distribution as growth proceeds. A
A Monte Carlo simulation of the evolution of the typical step profile after growth of about 1000 S A
kink distribution for a single step edge has been layers is shown in Fig. 4c. Straight lines at both sides
performed. As the fast diffusion direction on Si(001) of the step edge indicate the distance to the neigh-
is along the dimer rows, growth units are assumed to bouring steps. This simulated step edge profile shows
arrive exclusively at the S A segments (the step seg- the formation of straight step edge segments in be-
ments along the [110] direction in Fig. 4a). The tween the kink bunches, which is consistent with the
diffusion process itself has not been incorporated in experimental observations.
the simulation. Instead the positions at which the
growth units arrive at the [110] step edge segments
are generated randomly using a uniform distribution. 5. Discussion
Each growth unit will stick to the closest of two
neighbouring kink sites. However, the growth unit is Our model describes the behaviour of a single
removed if its addition to the kink site causes that isolated step. The step edge fluctuations remain an
kink to pass the neighbouring kink. In that case it order of magnitude smaller than those observed ex-
5. J. van Wingerden et aL / Surface Science 352-354 (1996) 641-645 645
perimentally. However, before growth of 1000 S A determine the relevance of the diffusion effect is
layers is completed, the fluctuations have become very difficult. This illustrates once more the need for
larger than the terrace width so that interactions a better knowledge of the basic microscopic pro-
between neighbouring steps can no longer be ne- cesses during growth.
glected. Step-step interactions will be governed by We conclude that microscopic evidence has been
the maintenance of local thermodynamic equilibrium presented which confirms that ripple formation dur-
in much the same way as kink-kink interactions. ing MBE is caused by the formation of long straight
These step-step interactions also cause the corre- step edge segments along [110]. Furthermore, we
lated bunching of kinks, which yields the macro- have presented a model to explain the onset of the
scopic ripple structure. ripple formation. This model shows the importance
Bales and Zangwill [6] have used a continuum of the fluctuations caused by the inherent discrete-
model to show that for certain growth conditions ness of the growth process. More investigations are
surface diffusion can lead to step edge instabilities. needed to understand the relation between the ripple
During step flow growth on Si(001) S B steps con- orientation and the step edge orientation.
sume most of the atoms of the upper terrace to
follow the S A steps, which therefore grow mainly by
incorporating atoms from the lower terrace. This
does yield the unstable situation described by Bales References
and Zangwill as growth from atoms of the lower
terrace is unstable because of the larger attachment [1] A.J. Pidduck, D.J. Robbins, I.M. Young and G. Patel, Thin
probability at the convex than at the concave step Solid Films 183 (1989) 255.
[2] J. van Wingerden, Y.A. Wiechers, P.M.L.O. Scholte and F.
edge parts. Although the slow diffusion perpendicu- Tuinstra, Surf. Sci. 331-333 (1995) 473.
lar to the dimer rows strongly reduces the effect, it [3] D.J. Chadi, Phys. Rev. Lett. 59 (1987) 1691.
could still lead to instability. It should be noted that [4] G. Brocks, P.J. Kelly and R. Car, Phys. Rev. Lett. 66 (1991)
the local thermodynamic equilibrium incorporated in 1729.
our model yields the highest growth rate at the [5] D. Dijkkamp, E.J. van Loenen and H.B. Elswijk, Proc. 3rd
NEC Syrup. on Fundamental Approach to New Material
concave parts of the step edges, which is the oppo-
Phases, Vol. 17, Springer Ser. Mater. Sci. (Springer, Berlin,
site of the diffusion effect. As already noted by Bales 1992) p. 85.
and Zangwill, numerical evaluation of their model to [6] G.S. Bales and A. Zangwill, Phys. Rev. B 41 (1990) 5500.