Modeling topographical density for geoid determinationThis article is one of a series of papers published in this Special Issue on the theme GEODESY.

2009 ◽  
Vol 46 (8) ◽  
pp. 571-585 ◽  
Author(s):  
Robert Kingdon ◽  
Petr Vaníček ◽  
Marcelo Santos
Keyword(s):  
Mass Density ◽  
Three Dimensional ◽  
Spherical Model ◽  
Gravity Potential ◽  
Geoidal Height ◽  
Geometrical Shape ◽  
Topographical Effects ◽  
Terrain Effects ◽  
Topographical Effect ◽  
Lake Waters

In geoid computation, effects of real three-dimensional topographic masses on the Earth’s gravity field must be accurately quantified and, in the Stokes–Helmert scheme, replaced with effects of those masses condensed on the geoid. The most comprehensive modern schemes for evaluation of topographical effects account for terrain effects, use a spherical model of topography, and incorporate two-dimensionally varying models of topographical mass density. In this contribution, we employ a three-dimensionally varying model of topographical density. We use Newton’s integration to determine the direct topographical effect (DTE) on gravity and primary indirect topographical effect (PITE) on gravity potential. Lastly, we apply Stokes’ integration to calculate the DTE, PITE, and secondary indirect topographical effect (SITE) on geoidal height. We focus here on validation of our results and demonstration of our software’s capabilities. We present results for the simple geometrical shape of a disc under various rotations and for the anomalous density of lake waters. Effects on geoidal height for these simulations reach centimetre level, up to 2.2 cm in magnitude. For a simulation of the effects of neglected mass anomalies of the lakes, we find results reaching 0.8 cm in magnitude. We examine the behavior of our results as calculated using various step sizes for numerical integration and by comparing numerical results with analytical results for the specific case of a disc. These results suggest that the maximum percent error of our results is about 23.5% for the DTE on gravity and 7.6% for the PITE on gravity potential.

Image formation analysis of thick biological specimens using three-dimensional power-spectra of through focus series

1994 ◽  
Vol 52 ◽  
pp. 124-125
Author(s):  
Karen F. Han
Keyword(s):  
Inelastic Scattering ◽  
Imaging Techniques ◽  
Mass Density ◽  
Relative Proportion ◽  
Three Dimensional ◽  
Power Spectra ◽  
Image Formation ◽  
Energy Filtering ◽  
Ewald Sphere ◽  
Nonlinear Imaging

The primary focus in our laboratory is the study of higher order chromatin structure using three dimensional electron microscope tomography. Three dimensional tomography involves the deconstruction of an object by combining multiple projection views of the object at different tilt angles, image intensities are not always accurate representations of the projected object mass density, due to the effects of electron-specimen interactions and microscope lens aberrations. Therefore, an understanding of the mechanism of image formation is important for interpreting the images. The image formation for thick biological specimens has been analyzed by using both energy filtering and Ewald sphere constructions. Surprisingly, there is a significant amount of coherent transfer for our thick specimens. The relative amount of coherent transfer is correlated with the relative proportion of elastically scattered electrons using electron energy loss spectoscopy and imaging techniques.Electron-specimen interactions include single and multiple, elastic and inelastic scattering. Multiple and inelastic scattering events give rise to nonlinear imaging effects which complicates the interpretation of collected images.

Ice-Phase Precipitation

2017 ◽  
Vol 58 ◽  
pp. 6.1-6.36 ◽  
Author(s):  
I. Gultepe ◽  
A. J. Heymsfield ◽  
P. R. Field ◽  
D. Axisa
Keyword(s):  
Collection Efficiency ◽  
Numerical Models ◽  
Mass Density ◽  
Three Dimensional ◽  
Phase Precipitation ◽  
Microphysical Parameters ◽  
Mass Size ◽  
Ice Water ◽  
Ice Phase

AbstractIce-phase precipitation occurs at Earth’s surface and may include various types of pristine crystals, rimed crystals, freezing droplets, secondary crystals, aggregates, graupel, hail, or combinations of any of these. Formation of ice-phase precipitation is directly related to environmental and cloud meteorological parameters that include available moisture, temperature, and three-dimensional wind speed and turbulence, as well as processes related to nucleation, cooling rate, and microphysics. Cloud microphysical parameters in the numerical models are resolved based on various processes such as nucleation, mixing, collision and coalescence, accretion, riming, secondary ice particle generation, turbulence, and cooling processes. These processes are usually parameterized based on assumed particle size distributions and ice crystal microphysical parameters such as mass, size, and number and mass density. Microphysical algorithms in the numerical models are developed based on their need for applications. Observations of ice-phase precipitation are performed using in situ and remote sensing platforms, including radars and satellite-based systems. Because of the low density of snow particles with small ice water content, their measurements and predictions at the surface can include large uncertainties. Wind and turbulence affecting collection efficiency of the sensors, calibration issues, and sensitivity of ground-based in situ observations of snow are important challenges to assessing the snow precipitation. This chapter’s goals are to provide an overview for accurately measuring and predicting ice-phase precipitation. The processes within and below cloud that affect falling snow, as well as the known sources of error that affect understanding and prediction of these processes, are discussed.

scholarly journals Measuring the Autocorrelation Function of Nanoscale Three-Dimensional Density Distribution in Individual Cells Using Scanning Transmission Electron Microscopy, Atomic Force Microscopy, and a New Deconvolution Algorithm

2017 ◽  
Vol 23 (3) ◽  
pp. 661-667 ◽  
Author(s):  
Yue Li ◽  
Di Zhang ◽  
Ilker Capoglu ◽  
Karl A. Hujsak ◽  
Dhwanil Damania ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Density Distribution ◽  
Scanning Transmission Electron Microscopy ◽  
Mass Density ◽  
Three Dimensional ◽  
Force Microscopy ◽  
Statistical Measures ◽  
Atomic Force ◽  
Transmission Electron ◽  
Scanning Transmission

AbstractEssentially all biological processes are highly dependent on the nanoscale architecture of the cellular components where these processes take place. Statistical measures, such as the autocorrelation function (ACF) of the three-dimensional (3D) mass–density distribution, are widely used to characterize cellular nanostructure. However, conventional methods of reconstruction of the deterministic 3D mass–density distribution, from which these statistical measures can be calculated, have been inadequate for thick biological structures, such as whole cells, due to the conflict between the need for nanoscale resolution and its inverse relationship with thickness after conventional tomographic reconstruction. To tackle the problem, we have developed a robust method to calculate the ACF of the 3D mass–density distribution without tomography. Assuming the biological mass distribution is isotropic, our method allows for accurate statistical characterization of the 3D mass–density distribution by ACF with two data sets: a single projection image by scanning transmission electron microscopy and a thickness map by atomic force microscopy. Here we present validation of the ACF reconstruction algorithm, as well as its application to calculate the statistics of the 3D distribution of mass–density in a region containing the nucleus of an entire mammalian cell. This method may provide important insights into architectural changes that accompany cellular processes.

scholarly journals Study and Design of a Horizontal Axis Wind Turbine (0.5 kW) Using Software Solid Works

2021 ◽  
pp. 1-17
Author(s):  
Hagninou E. V. Donnou ◽  
Drissa Boro ◽  
Jean Noé Fabiyi ◽  
Marius Tovoeho ◽  
Aristide B. Akpo
Keyword(s):  
Wind Energy ◽  
Wind Turbine ◽  
Wedge Angle ◽  
Three Dimensional ◽  
Synchronous Generator ◽  
Horizontal Axis ◽  
Geometrical Shape ◽  
Horizontal Axis Wind Turbine ◽  
Horizontal Axis Wind Turbines ◽  
Lift And Drag

In the present work, the study and design of a horizontal axis wind turbine suitable for the Cotonou site were investigated on the coast of Benin. A statistical study using the Weibull distribution was carried out on the hourly wind data measured at 10 m from the ground by the Agency for Air Navigation Safety in Africa and Madagascar (ASECNA) over the period from January 1981 to December 2014. Then, the models, techniques, tools and approaches used to design horizontal axis wind turbines were presented and the wind turbine components characteristics were determined. The numerical design and assembly of these components were carried out using SolidWorks software. The results revealed that the designed wind turbine has a power of 571W. It is equipped with a permanent magnet synchronous generator and has three aluminum blades with NACA 4412 biconvex asymmetrical profile. The values obtained for the optimum coefficient of lift and drag are estimated at 1.196 and 0.0189 respectively. The blades are characterised by an attack optimum angle estimated at 6° and the wedge angle at 5°. Their length is 2.50 m and the maximum thickness is estimated at 0.032 m for a rope length of 0.27 m. The wind turbine efficiency is 44%. The computer program designed on SolidWorks gives three-dimensional views of the geometrical shape of the wind turbine components and their assembly has allowed to visualize the compact shape of the wind turbine after export via its graphical interface. The energy quantity that can be obtained from the wind turbine was estimated at 2712,718 kWh/year. This wind turbine design study is the first of its kind for the study area. In order to reduce the technological dependence and the import of wind energy systems, the results of this study could be used to produce lower cost wind energy available on our study site.

Creation of Patterned Gold Nanostructures via Electron-Beam-Induced Deposition

2013 ◽  
Vol 1546 ◽  
Author(s):  
Anastasia V. Riazanova ◽  
Johannes J. L. Mulders ◽  
Lyubov M. Belova
Keyword(s):  
Electron Beam ◽  
Three Dimensional ◽  
Area Ratio ◽  
Ex Situ ◽  
Geometrical Shape ◽  
Local Electron ◽  
Post Annealing ◽  
Treatment Conditions ◽  
Heat Treated ◽  
Electron Beam Induced Deposition

ABSTRACTOne of the methods to grow nanoscale three-dimensional (3D) Au patterns is to perform local electron-beam-induced deposition (EBID) using the Me2Au(acac) precursor inside the chamber of a scanning electron microscope (SEM). However, due to the organometallic nature of the chemical, the concentration of the metallic constituent in the as-deposited structure is dramatically low, at around 10 at. % of Au. Ex-situ post-annealing of Me2Au(acac) EBIDs is a very promising purification approach, resulting in an Au content of > 92 at. % after annealing at 600 °C. However, in most of the cases it also distorts the geometrical shape of the heat-treated structure, preserving of which is essential for the application. In this paper we present a systematic study of the dependence between the annealing parameters and resulting purity in combination with the shape of the Au structure. Optimized heat treatment conditions for the creation of well-purified high aspect ratio Au pillar array are presented; and for planar continuous structures, the importance of the parameter height to area ratio is identified.

Accuracy of Water Quality Predictions with Loading Scenarios of Forest Industry Waste Waters

1999 ◽  
Vol 40 (11-12) ◽  
pp. 147-154
Author(s):  
Timo Huttula ◽  
Anu Peltonen ◽  
Tom Frisk ◽  
Hannu Wirola ◽  
Kirsti Krogerus
Keyword(s):  
Water Quality ◽  
Three Dimensional ◽  
Water Quality Monitoring ◽  
Pulp Mills ◽  
Quality Models ◽  
Environmental Evaluation ◽  
Industry Waste ◽  
Paper And Pulp ◽  
Lake Waters ◽  
Water Quality Models

The environmental effects of the Finnish industrial loadings are in practice decided by water courts as they give permits. In decision-making they use an inspection procedure. Since 1970s in Finland within this procedure one method of environmental evaluation has been the application of numerical water quality models. At the Kokemäenjoki watercourse water quality effects of the paper and pulp mills in Mänttä, Lielahti and Valkeakoski were studied with two or three dimensional water quality models. On the basis of these results the costs and benefits of different loading options were considered. Now, after more than a decade, the response of the lake waters to the nutrient and BOD loading can be seen in the water quality monitoring results. We used these observations and studied the accuracy and limitations of these early water quality models.

Color Space of Normally Sighted and Color-Deficient Observers Reconstructed from Color Naming

1996 ◽  
Vol 7 (5) ◽  
pp. 311-317 ◽  
Author(s):  
Galina V. Paramei
Keyword(s):  
Color Space ◽  
Three Dimensional ◽  
Spherical Model ◽  
Color Discrimination ◽  
Color Naming ◽  
Three Dimensions ◽  
Color Spaces ◽  
Experimental Procedure ◽  
Additional Information ◽  
Necessary And Sufficient

An experimental procedure based on the color-naming method introduced by Boynton, Schafer, and Neun (1964) was used to study the color appearance of equiluminant spectral stimuli in observers with congenital red-green color deficiencies, as well as in normal trichromats Subjects' responses (choice of one or more labels from the set red, yellow, green, blue, and white) were converted to numeric scores, which were used to estimate subjective differences between pairs of colors Individual subjects' matrices were processed by means of multidimensional scaling As in the direct rating of color dissimilarities in normal trichromats (Sokolov & Izmatlov, 1983) and color-deficient observers (Paramei Izmatlov, & Sokolov, 1991), these indirectly obtained measures yielded a color space in which three dimensions appear to be necessary and sufficient The dimensions are interpreted as evidence for red-green, blue-yellow, and achromatic (saturation) subsystems Based on the color-naming technique, three-dimensional spaces were reconstructed for the color-deficient observers These results were compared with those obtained by Helm (1964) It is argued that retaining more than one (blue-yellow) dimension in the color spaces of such observers provides additional information indicating preservation of residual red-green discrimination accompanied by finer discrimination of chroma than in normal trichromats The spherical model of color discrimination developed for normal trichromats (Izmatlov & Sokolov, 1991) is shown to be valid for color-deficient subjects as well and may be useful as a framework for differentiating protan and deutan types of color deficiency Colornaming functions, which seem not to reveal a differentiation between protans and deutans, provide results from which this differentiation can be extracted in reconstructed color spaces

scholarly journals GEOtop 2.0: simulating the combined energy and water balance at and below the land surface accounting for soil freezing, snow cover and terrain effects

2014 ◽  
Vol 7 (6) ◽  
pp. 2831-2857 ◽  
Author(s):  
S. Endrizzi ◽  
S. Gruber ◽  
M. Dall'Amico ◽  
R. Rigon
Keyword(s):  
Snow Cover ◽  
Land Surface ◽  
Three Dimensional ◽  
Soil Surface ◽  
Soil Freezing ◽  
Energy Budgets ◽  
Freezing And Thawing ◽  
Terrain Effects ◽  
Synthetic Simulation ◽  
Soil Freezing And Thawing

Abstract. GEOtop is a fine-scale grid-based simulator that represents the heat and water budgets at and below the soil surface. It describes the three-dimensional water flow in the soil and the energy exchange with the atmosphere, considering the radiative and turbulent fluxes. Furthermore, it reproduces the highly non-linear interactions between the water and energy balance during soil freezing and thawing, and simulates the temporal evolution of the water and energy budgets in the snow cover and their effect on soil temperature. Here, we present the core components of GEOtop 2.0 and demonstrate its functioning. Based on a synthetic simulation, we show that the interaction of processes represented in GEOtop 2.0 can result in phenomena that are significant and relevant for applications involving permafrost and seasonally frozen soils, both in high altitude and latitude regions.

scholarly journals Strain-induced control of a pillar cavity-GaAs single quantum dot photon source

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Inah Yeo ◽  
Doukyun Kim ◽  
Il Ki Han ◽  
Jin Dong Song
Keyword(s):  
Single Photon ◽  
Theoretical Calculations ◽  
Three Dimensional ◽  
Droplet Epitaxy ◽  
Geometrical Shape ◽  
Single Quantum Dot ◽  
On Chip ◽  
Quantum Error ◽  
Modal Stress ◽  
Photon Source

AbstractHerein, we present the calculated strain-induced control of single GaAs/AlGaAs quantum dots (QDs) integrated into semiconductor micropillar cavities. We show precise energy control of individual single GaAs QD excitons under multi-modal stress fields of tailored micropillar optomechanical resonators. Further, using a three-dimensional envelope-function model, we evaluated the quantum mechanical correction in the QD band structures depending on their geometrical shape asymmetries and, more interestingly, on the practical degree of Al interdiffusion. Our theoretical calculations provide the practical quantum error margins, obtained by evaluating Al-interdiffused QDs that were engineered through a front-edge droplet epitaxy technique, for tuning engineered QD single-photon sources, facilitating a scalable on-chip integration of QD entangled photons.

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