Intersection of three-dimensional geometric surfaces
NASA Technical Reports Server (NTRS)
Crisp, V. K.; Rehder, J. J.; Schwing, J. L.
1985-01-01
Calculating the line of intersection between two three-dimensional objects and using the information to generate a third object is a key element in a geometry development system. Techniques are presented for the generation of three-dimensional objects, the calculation of a line of intersection between two objects, and the construction of a resultant third object. The objects are closed surfaces consisting of adjacent bicubic parametric patches using Bezier basis functions. The intersection determination involves subdividing the patches that make up the objects until they are approximately planar and then calculating the intersection between planes. The resulting straight-line segments are connected to form the curve of intersection. The polygons in the neighborhood of the intersection are reconstructed and put back into the Bezier representation. A third object can be generated using various combinations of the original two. Several examples are presented. Special cases and problems were encountered, and the method for handling them is discussed. The special cases and problems included intersection of patch edges, gaps between adjacent patches because of unequal subdivision, holes, or islands within patches, and computer round-off error.
Surface fitting three-dimensional bodies
NASA Technical Reports Server (NTRS)
Dejarnette, F. R.; Ford, C. P., III
1975-01-01
The geometry of general three-dimensional bodies was generated from coordinates of points in several cross sections. Since these points may not be on smooth curves, they are divided into groups forming segments and general conic sections are curve fit in a least-squares sense to each segment of a cross section. The conic sections are then blended in the longitudinal direction through longitudinal curves. Both the cross-sectional and longitudinal curves may be modified by specifying particular segments as straight lines or specifying slopes at selected points. This method was used to surface fit a 70 deg slab delta wing and the HL-10 Lifting Body. The results for the delta wing were very close to the exact geometry. Although there is no exact solution for the lifting body, the surface fit generated a smooth surface with cross-sectional planes very close to prescribed coordinate points.
PLOT3D- DRAWING THREE DIMENSIONAL SURFACES
NASA Technical Reports Server (NTRS)
Canright, R. B.
1994-01-01
PLOT3D is a package of programs to draw three-dimensional surfaces of the form z = f(x,y). The function f and the boundary values for x and y are the input to PLOT3D. The surface thus defined may be drawn after arbitrary rotations. However, it is designed to draw only functions in rectangular coordinates expressed explicitly in the above form. It cannot, for example, draw a sphere. Output is by off-line incremental plotter or online microfilm recorder. This package, unlike other packages, will plot any function of the form z = f(x,y) and portrays continuous and bounded functions of two independent variables. With curve fitting; however, it can draw experimental data and pictures which cannot be expressed in the above form. The method used is division into a uniform rectangular grid of the given x and y ranges. The values of the supplied function at the grid points (x, y) are calculated and stored; this defines the surface. The surface is portrayed by connecting successive (y,z) points with straight-line segments for each x value on the grid and, in turn, connecting successive (x,z) points for each fixed y value on the grid. These lines are then projected by parallel projection onto the fixed yz-plane for plotting. This program has been implemented on the IBM 360/67 with on-line CDC microfilm recorder.
Surface fitting three-dimensional bodies
NASA Technical Reports Server (NTRS)
Dejarnette, F. R.
1974-01-01
The geometry of general three-dimensional bodies is generated from coordinates of points in several cross sections. Since these points may not be smooth, they are divided into segments and general conic sections are curve fit in a least-squares sense to each segment of a cross section. The conic sections are then blended in the longitudinal direction by fitting parametric cubic-spline curves through coordinate points which define the conic sections in the cross-sectional planes. Both the cross-sectional and longitudinal curves may be modified by specifying particular segments as straight lines and slopes at selected points. Slopes may be continuous or discontinuous and finite or infinite. After a satisfactory surface fit has been obtained, cards may be punched with the data necessary to form a geometry subroutine package for use in other computer programs. At any position on the body, coordinates, slopes and second partial derivatives are calculated. The method is applied to a blunted 70 deg delta wing, and it was found to generate the geometry very well.
Weinberg, SM; Naidoo, SD; Bardi, KM; Brandon, CA; Neiswanger, K; Resick, JM; Martin, RA; Marazita, ML
2009-01-01
Objective Various lines of evidence suggest that face shape may be a predisposing factor for nonsyndromic cleft lip with or without cleft palate (CL/P). In the present study, 3D surface imaging and statistical shape analysis were used to evaluate face shape differences between the unaffected (non-cleft) parents of individuals with CL/P and unrelated controls. Methods Sixteen facial landmarks were collected from 3D captures of 80 unaffected parents and 80 matched controls. Prior to analysis, each unaffected parent was assigned to a subgroup on the basis of prior family history (positive or negative). A geometric morphometric approach was utilized to scale and superimpose the landmark coordinate data (Procrustes analysis), test for omnibus group differences in face shape, and uncover specific modes of shape variation capable of discriminating unaffected parents from controls. Results Significant disparity in face shape was observed between unaffected parents and controls (p < 0.01). Notably, these changes were specific to parents with a positive family history of CL/P. Shape changes associated with CL/P predisposition included marked flattening of the facial profile (midface retrusion), reduced upper facial height, increased lower facial height and excess interorbital width. Additionally, a sex-specific pattern of parent-control difference was evident in the transverse dimensions of the nasolabial complex. Conclusions The faces of unaffected parents from multiplex cleft families display meaningful shape differences compared with the general population. Quantitative assessment of the facial phenotype in cleft families may enhance efforts to discover the root causes of CL/P. PMID:19840279
Jung, H.-S.; Lu, Zhiming; Won, J.-S.; Poland, Michael P.; Miklius, Asta
2011-01-01
Surface deformation caused by an intrusion and small eruption during June 17-19, 2007, along the East Rift Zone of Kilauea Volcano, Hawaii, was three-dimensionally reconstructed from radar interferograms acquired by the Advanced Land Observing Satellite (ALOS) phased-array type L-band synthetic aperture radar (SAR) (PALSAR) instrument. To retrieve the 3-D surface deformation, a method that combines multiple-aperture interferometry (MAI) and conventional interferometric SAR (InSAR) techniques was applied to one ascending and one descending ALOS PALSAR interferometric pair. The maximum displacements as a result of the intrusion and eruption are about 0.8, 2, and 0.7 m in the east, north, and up components, respectively. The radar-measured 3-D surface deformation agrees with GPS data from 24 sites on the volcano, and the root-mean-square errors in the east, north, and up components of the displacement are 1.6, 3.6, and 2.1 cm, respectively. Since a horizontal deformation of more than 1 m was dominantly in the north-northwest-south-southeast direction, a significant improvement of the north-south component measurement was achieved by the inclusion of MAI measurements that can reach a standard deviation of 3.6 cm. A 3-D deformation reconstruction through the combination of conventional InSAR and MAI will allow for better modeling, and hence, a more comprehensive understanding, of the source geometry associated with volcanic, seismic, and other processes that are manifested by surface deformation.
Computer program draws three-dimensional surfaces
NASA Technical Reports Server (NTRS)
Canright, R. B., Jr.; Swigert, P.
1972-01-01
Computer plotting program PLOT 3D draws views of surface forms z = f(x,y). Surface thus defined by program may be drawn after arbitrary rotations. Program portrays behavior of various functions involving two variables in many engineering, physics, and mathematical relationships.
Three-dimensional reconstructions of solid surfaces using conventional microscopes.
Ficker, Tomáš; Martišek, Dalibor
2016-01-01
The three-dimensional digital replicas of solid surfaces are subject of interest of different branches of science and technology. The present paper in its introductory parts brings an overview of the various microscopic reconstructive techniques based on optical sectioning. The main attention is devoted to conventional reconstruction methods and especially to that one employing the Fourier transform. The three-dimensional replicas of this special reconstructive frequency method are compared graphically and numerically with the three-dimensional replicas of the confocal method. Based on the comparative study it has been concluded that the quality of the conventional replicas of surfaces possessing textures of intermediate height irregularities is acceptable and almost comparable with the quality of confocal replicas. This study is relevant both for identifying a convenient technique that provides good qualities of three-dimensional replicas and for selecting the hardware whose price is affordable even for small research groups studying rougher surface textures. PMID:26381761
Three-dimensional object surface identification
NASA Astrophysics Data System (ADS)
Celenk, Mehmet
1995-03-01
This paper describes a computationally efficient matching method for inspecting 3D objects using their serial cross sections. Object regions of interest in cross-sectional binary images of successive slices are aligned with those of the models. Cross-sectional differences between the object and the models are measured in the direction of the gradient of the cross section boundary. This is repeated in all the cross-sectional images. The model with minimum average cross-sectional difference is selected as the best match to the given object (i.e., no defect). The method is tested using various computer generated surfaces and matching results are presented. It is also demonstrated using Symult S-2010 16-node system that the method is suitable for parallel implementation in massage passing processors with the maximum attainable speedup (close to 16 for S-2010).
Three-Dimensional Interactive Design Using Bezier Curves and Surfaces.
ERIC Educational Resources Information Center
Khonsari, M. M.; Horn, D.
1987-01-01
Offers a method for interactive design of objects on a computer. Outlines a method which allows the designer to interact with orthogonal views to construct a three dimensional model of an arbitrary shape. Presents an algorithm based on the Bezier curves to efficiently create smooth curves and surfaces. (CW)
Topographical parameters for specifying a three-dimensional surface.
Peltonen, Jouko; Järn, Mikael; Areva, Sami; Linden, Mika; Rosenholm, Jarl B
2004-10-26
The importance of different surface geometries and thereby the need for versatile surface identification by describing a number of different surface features is emphasized. A set of topographical parameters for the description of the amplitude and spatial and hybrid properties of surfaces was utilized for a versatile three-dimensional surface characterization of sol-gel samples with different topographies. The image data were measured by atomic force microscopy. The results demonstrate the power of the roughness parameters to identify surfaces according to their specific characteristics. An example is also given about how certain surface topographical properties may control the material reactivity. PMID:15491170
Three-dimensional surface reconstruction from multistatic SAR images.
Rigling, Brian D; Moses, Randolph L
2005-08-01
This paper discusses reconstruction of three-dimensional surfaces from multiple bistatic synthetic aperture radar (SAR) images. Techniques for surface reconstruction from multiple monostatic SAR images already exist, including interferometric processing and stereo SAR. We generalize these methods to obtain algorithms for bistatic interferometric SAR and bistatic stereo SAR. We also propose a framework for predicting the performance of our multistatic stereo SAR algorithm, and, from this framework, we suggest a metric for use in planning strategic deployment of multistatic assets. PMID:16121463
Three-dimensional potential energy surface of Ar–CO
Sumiyoshi, Yoshihiro; Endo, Yasuki
2015-01-14
A three-dimensional intermolecular potential energy surface of the Ar–CO complex has been determined by fitting most of the previously reported spectroscopic data, where observed transition frequencies by microwave, millimeter-wave, submillimeter-wave, and infrared spectroscopy were reproduced simultaneously within their experimental accuracies. A free rotor model Hamiltonian considering all the freedom of motions for an atom-diatom system was applied to calculate vibration-rotation energies. A three-dimensional potential energy surface obtained by ab initio calculations at the CCSD(T)-F12b/aug-cc-pV5Z level of theory was parameterized by a model function consisting of 46 parameters. They were used as initial values for the least-squares analysis of the experimental data. A total of 20 parameters were optimized to reproduce all the spectroscopic data.
Chiral Surface Modes in Three-Dimensional Topological Insulators
NASA Astrophysics Data System (ADS)
Hattori, Kiminori; Okamoto, Hiroaki
2016-05-01
Where chiral modes should appear is an essential question for the quantum anomalous Hall (QAH) effect in three-dimensional topological insulators (3DTIs). In this letter, we show that in a slab of ferromagnetic 3DTI subjected to a uniform exchange field normal to its top and bottom surfaces, the QAH effect creates a single chiral surface mode delocalized on the side faces. In a nonmagnetic 3DTI, analogously, delocalized helical modes consisting of a pair of oppositely propagating chiral surface modes are produced by the quantum spin Hall effect.
Three-dimensional surface reconstruction for industrial computed tomography
NASA Technical Reports Server (NTRS)
Vannier, M. W.; Knapp, R. H.; Gayou, D. E.; Sammon, N. P.; Butterfield, R. L.; Larson, J. W.
1985-01-01
Modern high resolution medical computed tomography (CT) scanners can produce geometrically accurate sectional images of many types of industrial objects. Computer software has been developed to convert serial CT scans into a three-dimensional surface form, suitable for display on the scanner itself. This software, originally developed for imaging the skull, has been adapted for application to industrial CT scanning, where serial CT scans thrrough an object of interest may be reconstructed to demonstrate spatial relationships in three dimensions that cannot be easily understood using the original slices. The methods of three-dimensional reconstruction and solid modeling are reviewed, and reconstruction in three dimensions from CT scans through familiar objects is demonstrated.
Algebraic surface grid generation in three-dimensional space
NASA Technical Reports Server (NTRS)
Warsi, Saif
1992-01-01
An interactive program for algebraic generation of structured surface grids in three dimensional space was developed on the IRIS4D series workstations. Interactive tools are available to ease construction of edge curves and surfaces in 3-D space. Addition, removal, or redistribution of points at arbitrary locations on a general 3-D surface or curve is possible. Also, redistribution of surface grid points may be accomplished through use of conventional surface splines or a method called 'surface constrained transfinite interpolation'. This method allows the user to redistribute the grid points on the edges of a surface patch; the effect of the redistribution is then propagated to the remainder of the surface through a transfinite interpolation procedure where the grid points will be constrained to lie on the surface. The program was written to be highly functional and easy to use. A host of utilities are available to ease the grid generation process. Generality of the program allows the creation of single and multizonal surface grids according to the user requirements. The program communicates with the user through popup menus, windows, and the mouse.
The perception of three-dimensionality across continuous surfaces
NASA Technical Reports Server (NTRS)
Stevens, Kent A.
1989-01-01
The apparent three-dimensionality of a viewed surface presumably corresponds to several internal preceptual quantities, such as surface curvature, local surface orientation, and depth. These quantities are mathematically related for points within the silhouette bounds of a smooth, continuous surface. For instance, surface curvature is related to the rate of change of local surface orientation, and surface orientation is related to the local gradient of distance. It is not clear to what extent these 3D quantities are determined directly from image information rather than indirectly from mathematically related forms, by differentiation or by integration within boundary constraints. An open empirical question, for example, is to what extent surface curvature is perceived directly, and to what extent it is quantitative rather than qualitative. In addition to surface orientation and curvature, one derives an impression of depth, i.e., variations in apparent egocentric distance. A static orthographic image is essentially devoid of depth information, and any quantitative depth impression must be inferred from surface orientation and other sources. Such conversion of orientation to depth does appear to occur, and even to prevail over stereoscopic depth information under some circumstances.
Three-dimensional surface imaging system for assessing human obesity
Yu, Wurong; Yao, Ming; Pepper, M. Reese; Freeland-Graves, Jeanne H.
2009-01-01
The increasing prevalence of obesity suggests a need to develop a convenient, reliable, and economical tool for assessment of this condition. Three-dimensional (3-D) body surface imaging has emerged as an exciting technology for the estimation of body composition. We present a new 3-D body imaging system, which is designed for enhanced portability, affordability, and functionality. In this system, stereo vision technology is used to satisfy the requirement for a simple hardware setup and fast image acquisition. The portability of the system is created via a two-stand configuration, and the accuracy of body volume measurements is improved by customizing stereo matching and surface reconstruction algorithms that target specific problems in 3-D body imaging. Body measurement functions dedicated to body composition assessment also are developed. The overall performance of the system is evaluated in human subjects by comparison to other conventional anthropometric methods, as well as air displacement plethysmography, for body fat assessment. PMID:19966948
Three-dimensional surface imaging system for assessing human obesity
NASA Astrophysics Data System (ADS)
Xu, Bugao; Yu, Wurong; Yao, Ming; Pepper, M. Reese; Freeland-Graves, Jeanne H.
2009-10-01
The increasing prevalence of obesity suggests a need to develop a convenient, reliable, and economical tool for assessment of this condition. Three-dimensional (3-D) body surface imaging has emerged as an exciting technology for the estimation of body composition. We present a new 3-D body imaging system, which is designed for enhanced portability, affordability, and functionality. In this system, stereo vision technology is used to satisfy the requirement for a simple hardware setup and fast image acquisition. The portability of the system is created via a two-stand configuration, and the accuracy of body volume measurements is improved by customizing stereo matching and surface reconstruction algorithms that target specific problems in 3-D body imaging. Body measurement functions dedicated to body composition assessment also are developed. The overall performance of the system is evaluated in human subjects by comparison to other conventional anthropometric methods, as well as air displacement plethysmography, for body fat assessment.
A new mosaic method for three-dimensional surface
NASA Astrophysics Data System (ADS)
Yuan, Yun; Zhu, Zhaokun; Ding, Yongjun
2011-08-01
Three-dimensional (3-D) data mosaic is a indispensable link in surface measurement and digital terrain map generation. With respect to the mosaic problem of the local unorganized cloud points with rude registration and mass mismatched points, a new mosaic method for 3-D surface based on RANSAC is proposed. Every circular of this method is processed sequentially by random sample with additional shape constraint, data normalization of cloud points, absolute orientation, data denormalization of cloud points, inlier number statistic, etc. After N random sample trials the largest consensus set is selected, and at last the model is re-estimated using all the points in the selected subset. The minimal subset is composed of three non-colinear points which form a triangle. The shape of triangle is considered in random sample selection in order to make the sample selection reasonable. A new coordinate system transformation algorithm presented in this paper is used to avoid the singularity. The whole rotation transformation between the two coordinate systems can be solved by twice rotations expressed by Euler angle vector, each rotation has explicit physical means. Both simulation and real data are used to prove the correctness and validity of this mosaic method. This method has better noise immunity due to its robust estimation property, and has high accuracy as the shape constraint is added to random sample and the data normalization added to the absolute orientation. This method is applicable for high precision measurement of three-dimensional surface and also for the 3-D terrain mosaic.
A Three-Dimensional Receiver Operator Characteristic Surface Diagnostic Metric
NASA Technical Reports Server (NTRS)
Simon, Donald L.
2011-01-01
Receiver Operator Characteristic (ROC) curves are commonly applied as metrics for quantifying the performance of binary fault detection systems. An ROC curve provides a visual representation of a detection system s True Positive Rate versus False Positive Rate sensitivity as the detection threshold is varied. The area under the curve provides a measure of fault detection performance independent of the applied detection threshold. While the standard ROC curve is well suited for quantifying binary fault detection performance, it is not suitable for quantifying the classification performance of multi-fault classification problems. Furthermore, it does not provide a measure of diagnostic latency. To address these shortcomings, a novel three-dimensional receiver operator characteristic (3D ROC) surface metric has been developed. This is done by generating and applying two separate curves: the standard ROC curve reflecting fault detection performance, and a second curve reflecting fault classification performance. A third dimension, diagnostic latency, is added giving rise to 3D ROC surfaces. Applying numerical integration techniques, the volumes under and between the surfaces are calculated to produce metrics of the diagnostic system s detection and classification performance. This paper will describe the 3D ROC surface metric in detail, and present an example of its application for quantifying the performance of aircraft engine gas path diagnostic methods. Metric limitations and potential enhancements are also discussed
Highly Crystalline Multimetallic Nanoframes with Three-Dimensional Electrocatalytic Surfaces
Chen, Chen; Kang, Yijin; Huo, Ziyang; Zhu, Zhongwei; Huang, Wenyu; Xin, Huolin; Snyder, Joshua; Li, Dongguo; Herron, Jeffrey A.; Mavrikakis, Manos; Chi, Miaofang; More, Karren L.; Li, Yadong; Markovic, Nenad M.; Somorjai, Gabor A.; Yang, Peidong; Stamenkovic, Vojislav R.
2014-03-21
Control of structure at the atomic level can precisely and effectively tune catalytic properties of materials, enabling enhancement in both activity and durability. We synthesized a highly active and durable class of electrocatalysts by exploiting the structural evolution of platinum-nickel (Pt-Ni) bimetallic nanocrystals. The starting material, crystalline PtNi_{3} polyhedra, transforms in solution by interior erosion into Pt_{3}Ni nanoframes with surfaces that offer three-dimensional molecular accessibility. The edges of the Pt-rich PtNi_{3} polyhedra are maintained in the final Pt_{3}Ni nanoframes. Both the interior and exterior catalytic surfaces of this open-framework structure are composed of the nanosegregated Pt-skin structure, which exhibits enhanced oxygen reduction reaction (ORR) activity. The Pt_{3}Ni nanoframe catalysts achieved a factor of 36 enhancement in mass activity and a factor of 22 enhancement in specific activity, respectively, for this reaction (relative to state-of-the-art platinum-carbon catalysts) during prolonged exposure to reaction conditions.
Three-dimensional reconstruction of surface nanoarchitecture from two-dimensional datasets
2014-01-01
The design of biomaterial surfaces relies heavily on the ability to accurately measure and visualize the three-dimensional surface nanoarchitecture of substrata. Here, we present a technique for producing three-dimensional surface models using displacement maps that are based on the data obtained from two-dimensional analyses. This technique is particularly useful when applied to scanning electron micrographs that have been calibrated using atomic force microscopy (AFM) roughness data. The evaluation of four different surface types, including thin titanium films, silicon wafers, polystyrene cell culture dishes and dragonfly wings confirmed that this technique is particularly effective for the visualization of conductive surfaces such as metallic titanium. The technique is particularly useful for visualizing surfaces that cannot be easily analyzed using AFM. The speed and ease with which electron micrographs can be recorded, combined with a relatively simple process for generating displacement maps, make this technique useful for the assessment of the surface topography of biomaterials. PMID:24410821
Three-dimensional surface anthropometry: Applications to the human body
NASA Astrophysics Data System (ADS)
Jones, Peter R. M.; Rioux, Marc
1997-09-01
Anthropometry is the study of the measurement of the human body. By tradition this has been carried out taking the measurements from body surface landmarks, such as circumferences and breadths, using simple instruments like tape measures and calipers. Three-dimensional (3D) surface anthropometry enables us to extend the study to 3D geometry and morphology of mainly external human body tissues. It includes the acquisition, indexing, transmission, archiving, retrieval, interrogation and analysis of body size, shape, and surface together with their variability throughout growth and development to adulthood. While 3D surface anthropometry surveying is relatively new, anthropometric surveying using traditional tools, such as calipers and tape measures, is not. Recorded studies of the human form date back to ancient times. Since at least the 17th century 1 investigators have made attempts to measure the human body for physical properties such as weight, size, and centre of mass. Martin documented 'standard' body measurement methods in a handbook in 1928. 2 This paper reviews the past and current literature devoted to the applications of 3D anthropometry because true 3D scanning of the complete human body is fast becoming a reality. We attempt to take readers through different forms of technology which deal with simple forms of projected light to the more complex advanced forms of laser and video technology giving low and/or high resolution 3D data. Information is also given about image capture of size and shape of the whole as well as most component parts of the human body. In particular, the review describes with explanations a multitude of applications, for example, medical, product design, human engineering, anthropometry and ergonomics etc.
Combined Labelled and Label-free SERS Probes for Triplex Three-dimensional Cellular Imaging
NASA Astrophysics Data System (ADS)
Chen, Yong; Bai, Xiangru; Su, Le; Du, Zhanwei; Shen, Aiguo; Materny, Arnulf; Hu, Jiming
2016-01-01
Cells are complex chemical systems, where the molecular composition at different cellular locations and specific intracellular chemical interactions determine the biological function. An in-situ nondestructive characterization of the complicated chemical processes (like e.g. apoptosis) is the goal of our study. Here, we present the results of simultaneous and three-dimensional imaging of double organelles (nucleus and membrane) in single HeLa cells by means of either labelled or label-free surface-enhanced Raman spectroscopy (SERS). This combination of imaging with and without labels is not possible when using fluorescence microscopy. The SERS technique is used for a stereoscopic description of the intrinsic chemical nature of nuclei and the precise localization of folate (FA) and luteinizing hormone-releasing hormone (LHRH) on the membrane under highly confocal conditions. We also report on the time-dependent changes of cell nuclei as well as membrane receptor proteins during apoptosis analyzed by statistical multivariate methods. The multiplex three-dimensional SERS imaging technique allows for both temporal (real time) and spatial (multiple organelles and molecules in three-dimensional space) live-cell imaging and therefore provides a new and attractive 2D/3D tracing method in biomedicine on subcellular level.
Combined Labelled and Label-free SERS Probes for Triplex Three-dimensional Cellular Imaging.
Chen, Yong; Bai, Xiangru; Su, Le; Du, Zhanwei; Shen, Aiguo; Materny, Arnulf; Hu, Jiming
2016-01-01
Cells are complex chemical systems, where the molecular composition at different cellular locations and specific intracellular chemical interactions determine the biological function. An in-situ nondestructive characterization of the complicated chemical processes (like e.g. apoptosis) is the goal of our study. Here, we present the results of simultaneous and three-dimensional imaging of double organelles (nucleus and membrane) in single HeLa cells by means of either labelled or label-free surface-enhanced Raman spectroscopy (SERS). This combination of imaging with and without labels is not possible when using fluorescence microscopy. The SERS technique is used for a stereoscopic description of the intrinsic chemical nature of nuclei and the precise localization of folate (FA) and luteinizing hormone-releasing hormone (LHRH) on the membrane under highly confocal conditions. We also report on the time-dependent changes of cell nuclei as well as membrane receptor proteins during apoptosis analyzed by statistical multivariate methods. The multiplex three-dimensional SERS imaging technique allows for both temporal (real time) and spatial (multiple organelles and molecules in three-dimensional space) live-cell imaging and therefore provides a new and attractive 2D/3D tracing method in biomedicine on subcellular level. PMID:26781186
Combined Labelled and Label-free SERS Probes for Triplex Three-dimensional Cellular Imaging
Chen, Yong; Bai, Xiangru; Su, Le; Du, Zhanwei; Shen, Aiguo; Materny, Arnulf; Hu, Jiming
2016-01-01
Cells are complex chemical systems, where the molecular composition at different cellular locations and specific intracellular chemical interactions determine the biological function. An in-situ nondestructive characterization of the complicated chemical processes (like e.g. apoptosis) is the goal of our study. Here, we present the results of simultaneous and three-dimensional imaging of double organelles (nucleus and membrane) in single HeLa cells by means of either labelled or label-free surface-enhanced Raman spectroscopy (SERS). This combination of imaging with and without labels is not possible when using fluorescence microscopy. The SERS technique is used for a stereoscopic description of the intrinsic chemical nature of nuclei and the precise localization of folate (FA) and luteinizing hormone-releasing hormone (LHRH) on the membrane under highly confocal conditions. We also report on the time-dependent changes of cell nuclei as well as membrane receptor proteins during apoptosis analyzed by statistical multivariate methods. The multiplex three-dimensional SERS imaging technique allows for both temporal (real time) and spatial (multiple organelles and molecules in three-dimensional space) live-cell imaging and therefore provides a new and attractive 2D/3D tracing method in biomedicine on subcellular level. PMID:26781186
Three-dimensional wake of a surface-mounted ellipsoid
NASA Astrophysics Data System (ADS)
Walter, Joel Allan
1997-11-01
A tri-axial ellipsoid mounted on a plane wall serves as a prototypical body for the study of three-dimensional flow phenomena. Extensive measurements of mean velocity and Reynolds stresses were made in the wake of the ellipsoid for three cases: at zero incidence, when the separating boundary layer of the ellipsoid was either laminar or turbulent, and at 6 degrees incidence when the separating boundary layer was turbulent. This thesis describes the main features of these flows and compares the three cases. Near the wall, the wake structure was dominated by fluid swept into the wall region by inboard flow from the tip, which is a consequence of the finite span of the body. In the central wake, the structure in the zero incidence cases differed dramatically depending on whether the originating ellipsoid boundary layer was laminar or turbulent. In the laminar case, organized counter- rotating longitudinal vortex cells were observed aligned along the wake centerline. Although the strongest pair could still be detected 5 chord lengths downstream of the tip, their strength and spatial coherence decayed more rapidly than the tip vortex observed in the at-incidence case. The organized secondary flow disappeared when the originating boundary layer was turbulent. The origins of the two different wakes that developed from the same (symmetry) condition were investigated using surface flow visualization. In the at-incidence case, the influence of the tip vortex was felt all the way into the junction region. The main difference in turbulence structure from the zero- incidence case appeared to be caused by two opposing inviscid mechanisms: the tip vortex-induced flow and the ellipsoid's potential flow. In the central part of the wake, mean velocity data exhibited self-similarity in all three cases and showed surprising quantitative agreement with asymptotic plane wake theory. In some cases, the primary turbulent shear stress and turbulence kinetic energy exhibited self- similarity
Three-dimensional tomography of composite fracture surfaces.
Drummond, James L; De Carlo, Francesco; Super, Boaz J
2005-08-01
The goal of this project was to image the three-dimensional fracture interface of a dental composite with the use of X-ray tomography. With the use of the Advanced Photon Source (APS) at Argonne National Laboratory, three-dimensional images were obtained of the crack interface of a dental composite material that had been subjected to three different treatments: a control, cycled in air, and cycled in a 50/50 mixture by volume of ethanol and distilled water. The cycle-loaded treatments were for 100,000 cycles at a load between 80 and 100 N at 5 Hz. The crack interface extended over 28 slices for the control, 96 for the air-cycled specimen, and 83 slices for the 50/50 solution cycle specimen. It would appear that the fatiguing of the specimens allowed for an increase in the crack interface as demonstrated by the 3D tomographical analysis. This volume increase in the crack interface is attributed to a separation of the filler fiber from the resin matrix. Three-dimensional tomography provides an excellent method to observe crack interfaces of dental composites subjected to different types of mechanical and environmental conditions. PMID:15981175
An improved evaluation of surface finish with a three dimensional tester
NASA Technical Reports Server (NTRS)
GRANDADAM; PREBET; RIOUT
1980-01-01
The design and programming of an automated three dimensional surface finish tester is described. The device produces a three dimensional image of the microscopic texture of the examined surface. The surface finish tester presents the following advantages over conventional profilometry: (1) more complete exploration of surface texture by successive probe sweeps; (2) automation of measuring and calculating; (3) more accurate representation of the derived parameters; (4) analysis of the degree of homogeneity of the surface; (5) three dimensional graphic representation accurately depicting the state of the surface; (6) detection of local imperfections; and (7) detection of scoring that occurred during machining.
Chang, Jessica B; Small, Kevin H; Choi, Mihye; Karp, Nolan S
2015-05-01
Three-dimensional surface imaging has gained clinical acceptance in plastic and reconstructive surgery. In contrast to computed tomography/magnetic resonance imaging, three-dimensional surface imaging relies on triangulation in stereophotography to measure surface x, y, and z coordinates. This study reviews the past, present, and future directions of three-dimensional topographic imaging in plastic surgery. Historically, three-dimensional imaging technology was first used in a clinical setting in 1944 to diagnose orthodontologic conditions. Karlan established its use in the field of plastic surgery in 1979, analyzing contours and documenting facial asymmetries. Present use of three-dimensional surface imaging has focused on standardizing patient topographic measurements to enhance preoperative planning and to improve postoperative outcomes. Various measurements (e.g., volume, surface area, vector distance, curvature) have been applied to breast, body, and facial topography to augment patient analysis. Despite the rapid progression of the clinical applications of three-dimensional imaging, current use of this technology is focused on the surgeon's perspective and secondarily the patient's perspective. Advancements in patient simulation may improve patient-physician communication, education, and satisfaction. However, a communal database of three-dimensional surface images integrated with emerging three-dimensional printing and portable information technology will validate measurements and strengthen preoperative planning and postoperative outcomes. Three-dimensional surface imaging is a useful adjunct to plastic and reconstructive surgery practices and standardizes measurements to create objectivity in a subjective field. Key improvements in three-dimensional imaging technology may significantly enhance the quality of plastic and reconstructive surgery in the near future. PMID:25835245
Numerical procedures for three-dimensional computational surface thermochemistry
NASA Technical Reports Server (NTRS)
Milos, Frank S.; Rasky, Daniel J.
1992-01-01
Models and equations for surface thermochemistry and near-surface thermophysics of aerodynamically-heated thermal protection materials are reviewed, with particular emphasis on computational boundary conditions for surface mass and energy transfer. The surface energy and mass balances, coupled with an appropriate ablation or surface catalysis model, provide complete thermochemical boundary conditions for a true multidisciplinary solution of the fully coupled fluid-dynamics/solid mechanics problem. Practical approximate solutions can be obtained by using a detailed model with full thermophysics for either the solid or fluid phase amd a semianalytic method for the other half of the problem. A significant increase in the state-of-the-art in aerothermal computational fluid dynamics is possible by uniting CFD methodology with surface thermochemistry boundary conditions and the heat-balance-integral method.
Superhydrophobic PDMS surfaces with three-dimensional (3D) pattern-dependent controllable adhesion
NASA Astrophysics Data System (ADS)
Yong, Jiale; Yang, Qing; Chen, Feng; Zhang, Dongshi; Du, Guangqing; Bian, Hao; Si, Jinhai; Yun, Feng; Hou, Xun
2014-01-01
In this paper, we demonstrate an effective approach for the three-dimensional (3D) pattern-structured superhydrophobic PDMS surfaces with controllable adhesion by using femtosecond laser etching method. By combining different laser power with a multi-layered etching way, various 3D patterns can be fabricated (for example, convex triangle array, round pit array, cylindrical array, convex rhombus array and concave triangle-cone array). The as-prepared surfaces with 3D patterns show superhydrophobic character and water controllable adhesion that range from ultralow to ultrahigh by designing different 3D patterns, on which the sliding angle can be controlled from 1° to 90° (the water droplet is firmly pinned on the superhydrophobic surface without any movement at any tilted angles). The 3D pattern-dependent adhesive property is attributed to the different contact modes. This work will provide a facile and promising strategy for the adhesion adjustment on superhydrophobic surfaces.
Three-dimensional surface phase imaging based on integrated thermo-optic swept laser
NASA Astrophysics Data System (ADS)
Kim, Hyo Jin; Cho, Jaedu; Noh, Young-Ouk; Oh, Min-Cheol; Chen, Zhongping; Kim, Chang-Seok
2014-03-01
We developed an optical frequency domain imaging (OFDI) system based on an integrated thermo-optic swept laser to achieve three-dimensional surface imaging. The wavelength was swept by applying a heating signal to a thermo-optic polymeric waveguide. The sub-micrometer surface profile was converted from the three-dimensional phase information of the OFDI system on various samples used as resolution targets with a step height of 120 nm.
Ji Yuanyuan; Koehler, Sven P. K.; Auerbach, Daniel J.; Wodtke, Alec M.
2010-07-15
The authors describe the application of a combination of velocity map imaging and time-of-flight (TOF) techniques to obtain three-dimensional velocity distributions for surface photodesorption. They have established a systematic alignment procedure to achieve correct and reproducible experimental conditions. It includes four steps: (1) optimization of the velocity map imaging ion optics' voltages to achieve optimum velocity map imaging conditions; (2) alignment of the surface normal with the symmetry axis (ion flight axis) of the ion optics; (3) determination of TOF distance between the surface and the ionizing laser beam; (4) alignment of the position of the ionizing laser beam with respect to the ion optics. They applied this set of alignment procedures and then measured Br({sup 2}P{sub 3/2}) (Br) and Br({sup 2}P{sub 1/2}) (Br*) atoms photodesorbing from a single crystal of KBr after exposure to 193 nm light. They analyzed the velocity flux and energy flux distributions for motion normal to the surface. The Br* normal energy distribution shows two clearly resolved peaks at approximately 0.017 and 0.39 eV, respectively. The former is slightly faster than expected for thermal desorption at the surface temperature and the latter is hyperthermal. The Br normal energy distribution shows a single broad peak that is likely composed of two hyperthermal components. The capability that surface three-dimensional velocity map imaging provides for measuring state-specific velocity distributions in all three dimensions separately and simultaneously for the products of surface photodesorption or surface reactions holds great promise to contribute to our understanding of these processes.
Evidence of Topological Surface State in Three-Dimensional Dirac Semimetal Cd3As2
Yi, Hemian; Wang, Zhijun; Chen, Chaoyu; Shi, Youguo; Feng, Ya; Liang, Aiji; Xie, Zhuojin; He, Shaolong; He, Junfeng; Peng, Yingying; Liu, Xu; Liu, Yan; Zhao, Lin; Liu, Guodong; Dong, Xiaoli; Zhang, Jun; Nakatake, M.; Arita, M.; Shimada, K.; Namatame, H.; Taniguchi, M.; Xu, Zuyan; Chen, Chuangtian; Dai, Xi; Fang, Zhong; Zhou, X. J.
2014-01-01
The three-dimensional topological semimetals represent a new quantum state of matter. Distinct from the surface state in the topological insulators that exhibits linear dispersion in two-dimensional momentum plane, the three-dimensional semimetals host bulk band dispersions linearly along all directions. In addition to the gapless points in the bulk, the three-dimensional Weyl/Dirac semimetals are also characterized by “topologically protected” surface state with Fermi arcs on their surface. While Cd3As2 is proposed to be a viable candidate of a Dirac semimetal, more investigations are necessary to pin down its nature. In particular, the topological surface state, the hallmark of the three-dimensional semimetal, has not been observed in Cd3As2. Here we report the electronic structure of Cd3As2 investigated by angle-resolved photoemission measurements on the (112) crystal surface and detailed band structure calculations. The measured Fermi surface and band structure show a good agreement with the band structure calculations with two bulk Dirac-like bands approaching the Fermi level and forming Dirac points near the Brillouin zone center. Moreover, the topological surface state with a linear dispersion approaching the Fermi level is identified for the first time. These results provide experimental indications on the nature of topologically non-trivial three-dimensional Dirac cones in Cd3As2. PMID:25139455
Structured light optical microscopy for three-dimensional reconstruction of technical surfaces
NASA Astrophysics Data System (ADS)
Kettel, Johannes; Reinecke, Holger; Müller, Claas
2016-04-01
In microsystems technology quality control of micro structured surfaces with different surface properties is playing an ever more important role. The process of quality control incorporates three-dimensional (3D) reconstruction of specularand diffusive reflecting technical surfaces. Due to the demand on high measurement accuracy and data acquisition rates, structured light optical microscopy has become a valuable solution to solve this problem providing high vertical and lateral resolution. However, 3D reconstruction of specular reflecting technical surfaces still remains a challenge to optical measurement principles. In this paper we present a measurement principle based on structured light optical microscopy which enables 3D reconstruction of specular- and diffusive reflecting technical surfaces. It is realized using two light paths of a stereo microscope equipped with different magnification levels. The right optical path of the stereo microscope is used to project structured light onto the object surface. The left optical path is used to capture the structured illuminated object surface with a camera. Structured light patterns are generated by a Digital Light Processing (DLP) device in combination with a high power Light Emitting Diode (LED). Structured light patterns are realized as a matrix of discrete light spots to illuminate defined areas on the object surface. The introduced measurement principle is based on multiple and parallel processed point measurements. Analysis of the measured Point Spread Function (PSF) by pattern recognition and model fitting algorithms enables the precise calculation of 3D coordinates. Using exemplary technical surfaces we demonstrate the successful application of our measurement principle.
NASA Technical Reports Server (NTRS)
Craidon, C. B.
1975-01-01
A computer program that uses a three-dimensional geometric technique for fitting a smooth surface to the component parts of an aircraft configuration is presented. The resulting surface equations are useful in performing various kinds of calculations in which a three-dimensional mathematical description is necessary. Programs options may be used to compute information for three-view and orthographic projections of the configuration as well as cross-section plots at any orientation through the configuration. The aircraft geometry input section of the program may be easily replaced with a surface point description in a different form so that the program could be of use for any three-dimensional surface equations.
NASA Technical Reports Server (NTRS)
Hsieh, Kwang-Chung
1992-01-01
The steady three-dimensional thermocapillary motion with a deformable free surface is studied numerically in both normal and zero gravity environments. Flow configurations consist of a square cavity heated from the side. In the analysis, the free surface is allowed to deform and the grid distribution is adapted to the surface deformation. The divergence-free condition is satisfied by using a dual time-stepping approach in the numerical scheme. Convective flux derivatives are evaluated using a third-order accurate upwind-biased flux-split differencing technique. The numerical solutions at the midplane of the square cavity are compared with the results from two-dimensional calculations. In addition, numerial results for cases under zero and normal gravity conditions are compared. Significantly different flow structures and surface deformation have been observed. The comparison of calculated results will be compared with experimental data in the updated version of this paper.
A microscale three-dimensional urban energy balance model for studying surface temperatures
NASA Astrophysics Data System (ADS)
Krayenhoff, E. Scott; Voogt, James A.
2007-06-01
A microscale three-dimensional (3-D) urban energy balance model, Temperatures of Urban Facets in 3-D (TUF-3D), is developed to predict urban surface temperatures for a variety of surface geometries and properties, weather conditions, and solar angles. The surface is composed of plane-parallel facets: roofs, walls, and streets, which are further sub-divided into identical square patches, resulting in a 3-D raster-type model geometry. The model code is structured into radiation, conduction and convection sub-models. The radiation sub-model uses the radiosity approach and accounts for multiple reflections and shading of direct solar radiation. Conduction is solved by finite differencing of the heat conduction equation, and convection is modelled by empirically relating patch heat transfer coefficients to the momentum forcing and the building morphology. The radiation and conduction sub-models are tested individually against measurements, and the complete model is tested against full-scale urban surface temperature and energy balance observations. Modelled surface temperatures perform well at both the facet-average and the sub-facet scales given the precision of the observations and the uncertainties in the model inputs. The model has several potential applications, such as the calculation of radiative loads, and the investigation of effective thermal anisotropy (when combined with a sensor-view model).
Combined three-dimensional computer vision and epi-illumination fluorescence imaging system
NASA Astrophysics Data System (ADS)
Gorpas, Dimitris; Yova, Dido; Politopoulos, Kostas
2012-03-01
Most of the reported fluorescence imaging methods and systems highlight the need for three-dimensional information of the inspected region surface geometry. The scope of this manuscript is to introduce an epi-illumination fluorescence imaging system, which has been enhanced with a binocular machine vision system for the translation of the inverse problem solution to the global coordinates system. The epi-illumination fluorescence imaging system is consisted of a structured scanning excitation source, which increases the spatial differentiation of the measured data, and a telecentric lens, which increases the angular differentiation. On the other hand, the binocular system is based on the projection of a structured light pattern on the inspected area, for the solution of the correspondence problem between the stereo pair. The functionality of the system has been evaluated on tissue phantoms and calibration objects. The reconstruction accuracy of the fluorophores distribution, as resulted from the root mean square error between the actual distribution and the outcome of the forward solver, was more than 80%. On the other hand, the surface three-dimensional reconstruction of the inspected region presented 0.067+/-0.004 mm accuracy, as resulted from the mean Euclidean distance between the three-dimensional position of the real world points and those reconstructed.
NASA Astrophysics Data System (ADS)
Duan, Qi; Angelini, Elsa D.; Herz, Susan L.; Ingrassia, Christopher M.; Gerard, Olivier; Costa, Kevin D.; Holmes, Jeffrey W.; Laine, Andrew F.
2005-04-01
With relatively high frame rates and the ability to acquire volume data sets with a stationary transducer, 3D ultrasound systems, based on matrix phased array transducers, provide valuable three-dimensional information, from which quantitative measures of cardiac function can be extracted. Such analyses require segmentation and visual tracking of the left ventricular endocardial border. Due to the large size of the volumetric data sets, manual tracing of the endocardial border is tedious and impractical for clinical applications. Therefore the development of automatic methods for tracking three-dimensional endocardial motion is essential. In this study, we evaluate a four-dimensional optical flow motion tracking algorithm to determine its capability to follow the endocardial border in three dimensional ultrasound data through time. The four-dimensional optical flow method was implemented using three-dimensional correlation. We tested the algorithm on an experimental open-chest dog data set and a clinical data set acquired with a Philips' iE33 three-dimensional ultrasound machine. Initialized with left ventricular endocardial data points obtained from manual tracing at end-diastole, the algorithm automatically tracked these points frame by frame through the whole cardiac cycle. A finite element surface was fitted through the data points obtained by both optical flow tracking and manual tracing by an experienced observer for quantitative comparison of the results. Parameterization of the finite element surfaces was performed and maps displaying relative differences between the manual and semi-automatic methods were compared. The results showed good consistency between manual tracing and optical flow estimation on 73% of the entire surface with fewer than 10% difference. In addition, the optical flow motion tracking algorithm greatly reduced processing time (about 94% reduction compared to human involvement per cardiac cycle) for analyzing cardiac function in three-dimensional
Worman, A.; Packman, A.I.; Marklund, L.; Harvey, J.W.; Stone, S.H.
2006-01-01
It has been long known that land surface topography governs both groundwater flow patterns at the regional-to-continental scale and on smaller scales such as in the hyporheic zone of streams. Here we show that the surface topography can be separated in a Fourier-series spectrum that provides an exact solution of the underlying three-dimensional groundwater flows. The new spectral solution offers a practical tool for fast calculation of subsurface flows in different hydrological applications and provides a theoretical platform for advancing conceptual understanding of the effect of landscape topography on subsurface flows. We also show how the spectrum of surface topography influences the residence time distribution for subsurface flows. The study indicates that the subsurface head variation decays exponentially with depth faster than it would with equivalent two-dimensional features, resulting in a shallower flow interaction. Copyright 2006 by the American Geophysical Union.
Surface representations of two- and three-dimensional fluid flow topology
NASA Technical Reports Server (NTRS)
Helman, James L.; Hesselink, Lambertus
1990-01-01
We discuss our work using critical point analysis to generate representations of the vector field topology of numerical flow data sets. Critical points are located and characterized in a two-dimensional domain, which may be either a two-dimensional flow field or the tangential velocity field near a three-dimensional body. Tangent curves are then integrated out along the principal directions of certain classes of critical points. The points and curves are linked to form a skeleton representing the two-dimensional vector field topology. When generated from the tangential velocity field near a body in a three-dimensional flow, the skeleton includes the critical points and curves which provide a basis for analyzing the three-dimensional structure of the flow separation. The points along the separation curves in the skeleton are used to start tangent curve integrations to generate surfaces representing the topology of the associated flow separations.
Aizenberg, Joanna; Burgess, Ian B.; Mishchenko, Lidiya; Hatton, Benjamin; Loncar, Marko
2016-03-08
A three-dimensional porous photonic structure, whose internal pore surfaces can be provided with desired surface properties in a spatially selective manner with arbitrary patterns, and methods for making the same are described. When exposed to a fluid (e.g., via immersion or wicking), the fluid can selectively penetrate the regions of the structure with compatible surface properties. Broad applications, for example in security, encryption and document authentication, as well as in areas such as simple microfluidics and diagnostics, are anticipated.
A numerical procedure for three-dimensional transient free surface seepage
NASA Astrophysics Data System (ADS)
Desai, C. S.; Lightner, J. G.; Somasundaram, S.
A three-dimensional procedure based on the finite element method is proposed for transient free surface seepage. It involves solution of the governing equations by using a time integration scheme. The procedure is applied for solution of confined, and transient free surface flow; the latter includes verification with respect to test results from a laboratory model. It is also applied to free surface flow through a dam with a crack.
Characterizing coral condition using estimates of three-dimensional colony surface area.
Fisher, William S; Davis, William P; Quarles, Robert L; Patrick, James; Campbell, Jed G; Harris, Peggy S; Hemmer, Becky L; Parsons, Mel
2007-02-01
Coral reefs provide shoreline protection, biological diversity, fishery harvests, and tourism, all values that stem from the physically-complex coral infrastructure. Stony corals (scleractinians) construct and maintain the reef through deposition of calcium carbonate. Therefore, assessment of coral reefs requires at least some measurement endpoints that reflect the biological and physical condition of stony corals. Most monitoring programs portray coral quantity as live coral cover, which is the two-dimensional proportion of coral surface to sea floor viewed from above (planar view). The absence of the third dimension, however, limits our ability to characterize coral reef value, physiology, health and sustainability. A three-dimensional (3D) approach more realistically characterizes coral structure available as community habitat and, when combined with estimates of live coral tissue, quantifies the amount of living coral available for photosynthesis, growth and reproduction. A rapid coral survey procedure that coupled 3D coral quantification with more traditional survey measurements was developed and tested in the field. The survey procedure relied on only three underwater observations--species identification, colony size, and proportion of live tissue--made on each colony in the transect. These observations generated a variety of metrics, including several based on 3D colony surface area, that are relevant to reef management. PMID:17225074
Resolving three-dimensional surface displacements from InSAR measurements: A review
NASA Astrophysics Data System (ADS)
Hu, J.; Li, Z. W.; Ding, X. L.; Zhu, J. J.; Zhang, L.; Sun, Q.
2014-06-01
One-dimensional measurement along the Line-Of-Sight (LOS) direction has greatly limited the capability of InSAR technique in the investigation of surface displacements and their dynamics. In recent years, great efforts have been made to resolve complete three-dimensional (3-D) displacements from InSAR measurements. This contribution is intended to provide a systematic review of the progress achieved in this field. Based on an analysis of the InSAR LOS measurements, we first cover two commonly used techniques, i.e., Offset-Tracking and multi-aperture InSAR (MAI), with which the surface displacement in the azimuth direction can be measured together with the LOS displacement. Several methods for mapping 3-D displacements using InSAR measurements are subsequently presented and categorized into three groups: (i) combination of multi-pass LOS and azimuth measurements; (ii) integration of InSAR and GPS data; and (iii) prior information assisted approaches. The strengths and weaknesses of each method are analyzed to show the applicability of each method to specific 3-D displacement mapping cases, in hope to provide a useful guidance in choosing a suitable approach accordingly. Finally, suggestions for resolving the challenging issues and outlook of future research are given.
Three dimensional surface slip partitioning of the Sichuan earthquake from Synthetic Aperture Radar
NASA Astrophysics Data System (ADS)
de Michele, M.; Raucoules, D.; de Sigoyer, J.; Pubellier, M.; Lasserre, C.; Pathier, E.; Klinger, Y.; van der Woerd, J.
2009-12-01
The Sichuan earthquake, Mw 7.9, struck the Longmen Shan range front, in the western Sichuan province, China, on 12 May 2008. It severely affected an area where little historical seismicity and little or no significant active shortening were reported before the earthquake (e.g. Gu et al., 1989; Chen et al., 1994; Gan et al., 2007). The Longmen Shan thrust system bounds the eastern margin of the Tibetan plateau and is considered as a transpressive zone since Triassic time that was reactivated during the India-Asia collision (e.g., Tapponnier and Molnar, 1977, Chen and Wilson 1996; Arne et al., 1997, Godard et al., 2009). However, contrasting geological evidences of sparse thrusting and marked dextral strike-slip faulting during the Quaternary along with high topography (Burchfiel et al., 1995; Densmore et al., 2007) have led to models of dynamically driven and sustained topography (Royden et al., 1997) limiting the role of earthquakes in relief building and leaving the mechanism of long term strain distribution in this area as an open question. Here we combine C and L band Synthetic Aperture Radar (SAR) offsets data from ascending and descending paths to retrieve the three dimensional surface slips distribution all along the earthquake ruptures of the Sichuan earthquake. We show a quantitative assessment of the amount of co-seismic slip and its partitioning at the surface.
Liu, Zhen; Li, Xiaojing; Li, Fengjiao; Zhang, Guangjun
2015-01-12
Single vision sensor cannot measure an entire object because of their limited field of view. Meanwhile, multiple rigidly-fixed vision sensors for the dynamic vision measurement of three-dimensional (3D) surface profilometry are complex and sensitive to strong environmental vibrations. To overcome these problems, a novel flexible dynamic measurement method for 3D surface profilometry based on multiple vision sensors is presented in this paper. A raster binocular stereo vision sensor is combined with a wide-field camera to produce a 3D optical probe. Multiple 3D optical probes are arranged around the object being measured, then many planar targets are set up. These planar targets function as the mediator to integrate the local 3D data measured by the raster binocular stereo vision sensors into the coordinate system. The proposed method is not sensitive to strong environmental vibrations, and the positions of these 3D optical probes need not be rigidly-fixed during the measurement. The validity of the proposed method is verified in a physical experiment with two 3D optical probes. When the measuring range of raster binocular stereo vision sensor is about 0.5 m × 0.38 m × 0.4 m and the size of the measured object is about 0.7 m, the accuracy of the proposed method could reach 0.12 mm. Meanwhile, the effectiveness of the proposed method in dynamic measurement is confirmed by measuring the rotating fan blades. PMID:25835684
A computer program for fitting smooth surfaces to three-dimensional aircraft configurations
NASA Technical Reports Server (NTRS)
Craidon, C. B.; Smith, R. E., Jr.
1975-01-01
A computer program developed to fit smooth surfaces to the component parts of three-dimensional aircraft configurations was described. The resulting equation definition of an aircraft numerical model is useful in obtaining continuous two-dimensional cross section plots in arbitrarily defined planes, local tangents, enriched surface plots and other pertinent geometric information; the geometry organization used as input to the program has become known as the Harris Wave Drag Geometry.
NASA Astrophysics Data System (ADS)
Matilla, A.; Mariné, J.; Pérez, J.; Cadevall, C.; Artigas, R.
2016-04-01
The most common optical measurement technologies used today for the three dimensional measurement of technical surfaces are Coherence Scanning Interferometry (CSI), Imaging Confocal Microscopy (IC), and Focus Variation (FV). Each one has its benefits and its drawbacks. FV will be the ideal technology for the measurement of those regions where the slopes are high and where the surface is very rough, while CSI and IC will provide better results for smoother and flatter surface regions. In this work we investigated the benefits and drawbacks of combining Interferometry, Confocal and focus variation to get better measurement of technical surfaces. We investigated a way of using Microdisplay Scanning type of Confocal Microscope to acquire on a simultaneous scan confocal and focus Variation information to reconstruct a three dimensional measurement. Several methods are presented to fuse the optical sectioning properties of both techniques as well as the topographical information. This work shows the benefit of this combination technique on several industrial samples where neither confocal nor focus variation is able to provide optimal results.
Three-dimensional surface grid generation for calculation of thermal radiation shape factors
NASA Technical Reports Server (NTRS)
Aly, Hany M.
1992-01-01
A technique is described to generate three dimensional surface grids suitable for calculating shape factors for thermal radiative heat transfer. The surface under consideration is approximated by finite triangular elements generated in a special manner. The grid is generated by dividing the surface into a two dimensional array of nodes. Each node is defined by its coordinates. Each set of four adjacent nodes is used to construct two triangular elements. Each triangular element is characterized by the vector representation of its vertices. Vector algebra is used to calculate all desired geometric properties of grid elements. The properties are used to determine the shape factor between the element and an area element in space. The grid generation can be graphically displayed using any software with three dimensional features. DISSPLA was used to view the grids.
A three dimensional scaffold with precise micro-architecture and surface micro-textures
Mata, Alvaro; Kim, Eun Jung; Boehm, Cynthia A.; Fleischman, Aaron J.; Muschler, George F.; Roy, Shuvo
2013-01-01
A three-dimensional (3D) structure comprising precisely defined microarchitecture and surface micro-textures, designed to present specific physical cues to cells and tissues, may provide an efficient scaffold in a variety of tissue engineering and regenerative medicine applications. We report a fabrication technique based on microfabrication and soft lithography that permits for the development of 3D scaffolds with both precisely engineered architecture and tailored surface topography. The scaffold fabrication technique consists of three key steps starting with microfabrication of a mold using an epoxy-based photoresist (SU-8), followed by dual-sided molding of a single layer of polydimethylsiloxane (PDMS) using a mechanical jig for precise motion control; and finally, alignment, stacking, and adhesion of multiple PDMS layers to achieve a 3D structure. This technique was used to produce 3D Texture and 3D Smooth PDMS scaffolds, where the surface topography comprised 10 μm-diameter/height posts and smooth surfaces, respectively. The potential utility of the 3D microfabricated scaffolds, and the role of surface topography, were subsequently investigated in vitro with a combined heterogeneous population of adult human stem cells and their resultant progenitor cells, collectively termed connective tissue progenitors (CTPs), under conditions promoting the osteoblastic phenotype. Examination of bone-marrow derived CTPs cultured on the 3D Texture scaffold for 9 days revealed cell growth in three dimensions and increased cell numbers compared to those on the 3D Smooth scaffold. Furthermore, expression of alkaline phosphatase mRNA was higher on the 3D Texture scaffold, while osteocalcin mRNA expression was comparable for both types of scaffolds. PMID:19524292
NASA Technical Reports Server (NTRS)
Gibson, A. F.
1983-01-01
A system of computer programs has been developed to model general three-dimensional surfaces. Surfaces are modeled as sets of parametric bicubic patches. There are also capabilities to transform coordinate to compute mesh/surface intersection normals, and to format input data for a transonic potential flow analysis. A graphical display of surface models and intersection normals is available. There are additional capabilities to regulate point spacing on input curves and to compute surface intersection curves. Internal details of the implementation of this system are explained, and maintenance procedures are specified.
Faceted Visualization of Three Dimensional Neuroanatomy By Combining Ontology with Faceted Search
Veeraraghavan, Harini; Miller, James V.
2013-01-01
In this work, we present a faceted-search based approach for visualization of anatomy by combining a three dimensional digital atlas with an anatomy ontology. Specifically, our approach provides a drill-down search interface that exposes the relevant pieces of information (obtained by searching the ontology) for a user query. Hence, the user can produce visualizations starting with minimally specified queries. Furthermore, by automatically translating the user queries into the controlled terminology our approach eliminates the need for the user to use controlled terminology. We demonstrate the scalability of our approach using an abdominal atlas and the same ontology. We implemented our visualization tool on the opensource 3D Slicer software. We present results of our visualization approach by combining a modified Foundational Model of Anatomy (FMA) ontology with the Surgical Planning Laboratory (SPL) Brain 3D digital atlas, and geometric models specific to patients computed using the SPL brain tumor dataset. PMID:24006207
Three dimensional transient behavior of thin films surface under pulsed laser excitation
NASA Astrophysics Data System (ADS)
Dimitriou, V.; Kaselouris, E.; Orphanos, Y.; Bakarezos, M.; Vainos, N.; Tatarakis, M.; Papadogiannis, N. A.
2013-09-01
The three dimensional spatiotemporal response of thin metal films surfaces excited by nanosecond laser pulses is investigated in both the thermoelastic and the ablation regimes. An experimental laser whole-field interferometric technique allows for the direct monitoring of the dynamic deformation of a macroscopic area on the surface with ultrahigh lateral resolution. A specially developed three dimension finite element model simulates the laser-surface interaction, predicts the experimentally obtained results, and computes key parameters of matter's thermomechanical response. This method provides a powerful instrument for spatiotemporal behavior of thin-film surfaces under extreme conditions demanded for innovative applications.
An Iterative Method for Improving the Quality of Reconstruction of a Three-Dimensional Surface
Vishnyakov, G.N.; Levin, G.G.; Sukhorukov, K.A.
2005-12-15
A complex image with constraints imposed on the amplitude and phase image components is processed using the Gerchberg iterative algorithm for the first time. The use of the Gerchberg iterative algorithm makes it possible to improve the quality of a three-dimensional surface profile reconstructed by the previously proposed method that is based on the multiangle projection of fringes and the joint processing of the obtained images by Fourier synthesis.
Microreplication of laser-fabricated surface and three-dimensional structures
NASA Astrophysics Data System (ADS)
Koroleva, Anastasia; Schlie, Sabrina; Fadeeva, Elena; Gittard, Shaun D.; Miller, Philip; Ovsianikov, Aleksandr; Koch, Jürgen; Narayan, Roger J.; Chichkov, Boris N.
2010-12-01
The fabrication of defined surface topographies and three-dimensional structures is a challenging process for various applications, e.g. in photonics and biomedicine. Laser-based technologies provide a promising approach for the production of such structures. The advantages of femtosecond laser ablation and two-photon polymerization for microstructuring are well known. However, these methods cannot be applied to all materials and are limited by their high cost and long production time. In this study, biomedical applications of an indirect rapid prototyping, molding microreplication of laser-fabricated two- and three-dimensional structures are examined. We demonstrate that by this method any laser-generated surface topography as well as three-dimensional structures can be replicated in various materials without losing the original geometry. The replication into multiple copies enables fast and perfect reproducibility of original microstructures for investigations of cell-surface interactions. Compared to unstructured materials, we observe that microstructures have strong influence on morphology and localization of fibroblasts, whereas neuroblastoma cells are not negatively affected.
NASA Astrophysics Data System (ADS)
Harvazinski, Matthew Evan
Self-excited combustion instabilities have been studied using a combination of two- and three-dimensional computational fluid dynamics (CFD) simulations. This work was undertaken to assess the ability of CFD simulations to generate the high-amplitude resonant combustion dynamics without external forcing or a combustion response function. Specifically, detached eddy simulations (DES), which allow for significantly coarser grid resolutions in wall bounded flows than traditional large eddy simulations (LES), were investigated for their capability of simulating the instability. A single-element laboratory rocket combustor which produces self-excited longitudinal instabilities is used for the configuration. The model rocket combustor uses an injector configuration based on practical oxidizer-rich staged-combustion devices; a sudden expansion combustion section; and uses decomposed hydrogen peroxide as the oxidizer and gaseous methane as the fuel. A better understanding of the physics has been achieved using a series of diagnostics. Standard CFD outputs like instantaneous and time averaged flowfield outputs are combined with other tools, like the Rayleigh index to provide additional insight. The Rayleigh index is used to identify local regions in the combustor which are responsible for driving and damping the instability. By comparing the Rayleigh index to flowfield parameters it is possible to connect damping and driving to specific flowfield conditions. A cost effective procedure to compute multidimensional local Rayleigh index was developed. This work shows that combustion instabilities can be qualitatively simulated using two-dimensional axisymmetric simulations for fuel rich operating conditions. A full three-dimensional simulation produces a higher level of instability which agrees quite well with the experimental results. In addition to matching the level of instability the three-dimensional simulation also predicts the harmonic nature of the instability that is
Walton, Richard D.; Smith, Rebecca M.; Mitrea, Bogdan G.; White, Edward; Bernus, Olivier; Pertsov, Arkady M.
2012-01-01
Optical mapping has become an indispensible tool for studying cardiac electrical activity. However, due to the three-dimensional nature of the optical signal, the optical upstroke is significantly longer than the electrical upstroke. This raises the issue of how to accurately determine the activation time on the epicardial surface. The purpose of this study was to establish a link between the optical upstroke and exact surface activation time using computer simulations, with subsequent validation by a combination of microelectrode recordings and optical mapping experiments. To simulate wave propagation and associated optical signals, we used a hybrid electro-optical model. We found that the time of the surface electrical activation (tE) within the accuracy of our simulations coincided with the maximal slope of the optical upstroke (tF∗) for a broad range of optical attenuation lengths. This was not the case when the activation time was determined at 50% amplitude (tF50) of the optical upstroke. The validation experiments were conducted in isolated Langendorff-perfused rat hearts and coronary-perfused pig left ventricles stained with either di-4-ANEPPS or the near-infrared dye di-4-ANBDQBS. We found that tF∗ was a more accurate measure of tE than was tF50 in all experimental settings tested (P = 0.0002). Using tF∗ instead of tF50 produced the most significant improvement in measurements of the conduction anisotropy and the transmural conduction time in pig ventricles. PMID:22225795
A new three-dimensional terrain-following tidal model of free-surface flows
NASA Astrophysics Data System (ADS)
Lu, Fuqiang; Zhang, Zhuo; Song, Zhiyao; Yue, Songshan; Wen, Yongning
2015-12-01
A three-dimensional hydrodynamic model is presented which combines a terrain-following vertical coordinate with a horizontally orthogonal curvilinear coordinate system to fit the complex bottom topography and coastlines near estuaries, continental shelves, and harbors. To solve the governing equations more efficiently, we improve the alternating direction implicit method, which is extensively used in the numerical modeling of horizontal two-dimensional shallow water equations, and extend it to a three-dimensional tidal model with relatively little computational effort. Through several test cases and realistic applications, as presented in the paper, it can be demonstrated that the model is capable of simulating the periodic to-and-fro currents, wind-driven flow, Ekman spirals, and tidal currents in the near-shore region.
Laser electro-optic system for rapid three-dimensional /3-D/ topographic mapping of surfaces
NASA Technical Reports Server (NTRS)
Altschuler, M. D.; Altschuler, B. R.; Taboada, J.
1981-01-01
It is pointed out that the generic utility of a robot in a factory/assembly environment could be substantially enhanced by providing a vision capability to the robot. A standard videocamera for robot vision provides a two-dimensional image which contains insufficient information for a detailed three-dimensional reconstruction of an object. Approaches which supply the additional information needed for the three-dimensional mapping of objects with complex surface shapes are briefly considered and a description is presented of a laser-based system which can provide three-dimensional vision to a robot. The system consists of a laser beam array generator, an optical image recorder, and software for controlling the required operations. The projection of a laser beam array onto a surface produces a dot pattern image which is viewed from one or more suitable perspectives. Attention is given to the mathematical method employed, the space coding technique, the approaches used for obtaining the transformation parameters, the optics for laser beam array generation, the hardware for beam array coding, and aspects of image acquisition.
NASA Astrophysics Data System (ADS)
Mitic, S.; Klumov, B. A.; Khrapak, S. A.; Morfill, G. E.
2013-04-01
We report on the first detailed analysis of large three dimensional (3D) complex plasma structures in experiments performed in pure rf and combined rf+dc discharge modes. Inductively coupled plasma is generated by an rf coil wrapped around the vertically positioned cylindrical glass tube at a pressure of 0.3 mbar. In addition, dc plasma can be generated by applying voltage to the electrodes at the ends of the tube far from the rf coil. The injected monodisperse particles are levitated in the plasma below the coil. A scanning laser sheet and a high resolution camera are used to determine the 3D positions of about 105 particles. The observed bowl-shaped particle clouds reveal coexistence of various structures, including well-distinguished solid-like, less ordered liquid-like, and pronounced string-like phases. New criteria to identify string-like structures are proposed.
Coma aberrations in combined two- and three-dimensional STED nanoscopy
Antonello, Jacopo; Kromann, Emil B.; Burke, Daniel; Bewersdorf, Joerg; Booth, Martin J.
2016-01-01
Stimulated emission depletion (STED) microscopes, like all super-resolution methods, are sensitive to aberrations. Of particular importance are aberrations that affect the quality of the depletion focus, which requires a point of near-zero intensity surrounded by strong illumination. We present analysis, modeling, and experimental measurements that show the effects of coma aberrations on depletion patterns of two-dimensional (2D) and three-dimensional (3D) STED configurations. Specifically, we find that identical coma aberrations create focal shifts in opposite directions in 2D and 3D STED. This phenomenon could affect the precision of microscopic measurements and has ramifications for the efficacy of combined 2D/3D STED systems. PMID:27472636
Coma aberrations in combined two- and three-dimensional STED nanoscopy.
Antonello, Jacopo; Kromann, Emil B; Burke, Daniel; Bewersdorf, Joerg; Booth, Martin J
2016-08-01
Stimulated emission depletion (STED) microscopes, like all super-resolution methods, are sensitive to aberrations. Of particular importance are aberrations that affect the quality of the depletion focus, which requires a point of near-zero intensity surrounded by strong illumination. We present analysis, modeling, and experimental measurements that show the effects of coma aberrations on depletion patterns of two-dimensional (2D) and three-dimensional (3D) STED configurations. Specifically, we find that identical coma aberrations create focal shifts in opposite directions in 2D and 3D STED. This phenomenon could affect the precision of microscopic measurements and has ramifications for the efficacy of combined 2D/3D STED systems. PMID:27472636
Mitic, S.; Morfill, G. E.; Klumov, B. A.; Khrapak, S. A.
2013-04-15
We report on the first detailed analysis of large three dimensional (3D) complex plasma structures in experiments performed in pure rf and combined rf+dc discharge modes. Inductively coupled plasma is generated by an rf coil wrapped around the vertically positioned cylindrical glass tube at a pressure of 0.3 mbar. In addition, dc plasma can be generated by applying voltage to the electrodes at the ends of the tube far from the rf coil. The injected monodisperse particles are levitated in the plasma below the coil. A scanning laser sheet and a high resolution camera are used to determine the 3D positions of about 10{sup 5} particles. The observed bowl-shaped particle clouds reveal coexistence of various structures, including well-distinguished solid-like, less ordered liquid-like, and pronounced string-like phases. New criteria to identify string-like structures are proposed.
Urbanová, Petra; Hejna, Petr; Jurda, Mikoláš
2015-05-01
Three-dimensional surface technologies particularly close range photogrammetry and optical surface scanning have recently advanced into affordable, flexible and accurate techniques. Forensic postmortem investigation as performed on a daily basis, however, has not yet fully benefited from their potentials. In the present paper, we tested two approaches to 3D external body documentation - digital camera-based photogrammetry combined with commercial Agisoft PhotoScan(®) software and stereophotogrammetry-based Vectra H1(®), a portable handheld surface scanner. In order to conduct the study three human subjects were selected, a living person, a 25-year-old female, and two forensic cases admitted for postmortem examination at the Department of Forensic Medicine, Hradec Králové, Czech Republic (both 63-year-old males), one dead to traumatic, self-inflicted, injuries (suicide by hanging), the other diagnosed with the heart failure. All three cases were photographed in 360° manner with a Nikon 7000 digital camera and simultaneously documented with the handheld scanner. In addition to having recorded the pre-autopsy phase of the forensic cases, both techniques were employed in various stages of autopsy. The sets of collected digital images (approximately 100 per case) were further processed to generate point clouds and 3D meshes. Final 3D models (a pair per individual) were counted for numbers of points and polygons, then assessed visually and compared quantitatively using ICP alignment algorithm and a cloud point comparison technique based on closest point to point distances. Both techniques were proven to be easy to handle and equally laborious. While collecting the images at autopsy took around 20min, the post-processing was much more time-demanding and required up to 10h of computation time. Moreover, for the full-body scanning the post-processing of the handheld scanner required rather time-consuming manual image alignment. In all instances the applied approaches
Three-Dimensional Computational Model for Flow in an Over-Expanded Nozzle With Porous Surfaces
NASA Technical Reports Server (NTRS)
Abdol-Hamid, K. S.; Elmiligui, Alaa; Hunter, Craig A.; Massey, Steven J.
2006-01-01
A three-Dimensional computational model is used to simulate flow in a non-axisymmetric, convergent-divergent nozzle incorporating porous cavities for shock-boundary layer interaction control. The nozzle has an expansion ratio (exit area/throat area) of 1.797 and a design nozzle pressure ratio of 8.78. Flow fields for the baseline nozzle (no porosity) and for the nozzle with porous surfaces of 10% openness are computed for Nozzle Pressure Ratio (NPR) varying from 1.29 to 9.54. The three dimensional computational results indicate that baseline (no porosity) nozzle performance is dominated by unstable, shock-induced, boundary-layer separation at over-expanded conditions. For NPR less than or equal to 1.8, the separation is three dimensional, somewhat unsteady, and confined to a bubble (with partial reattachment over the nozzle flap). For NPR greater than or equal to 2.0, separation is steady and fully detached, and becomes more two dimensional as NPR increased. Numerical simulation of porous configurations indicates that a porous patch is capable of controlling off design separation in the nozzle by either alleviating separation or by encouraging stable separation of the exhaust flow. In the present paper, computational simulation results, wall centerline pressure, mach contours, and thrust efficiency ratio are presented, discussed and compared with experimental data. Results indicate that comparisons are in good agreement with experimental data. The three-dimensional simulation improves the comparisons for over-expanded flow conditions as compared with two-dimensional assumptions.
Transport signatures of surface potentials on three-dimensional topological insulators
NASA Astrophysics Data System (ADS)
Roy, Sthitadhi; Das, Sourin
2016-02-01
The spin-momentum-locked nature of the robust surface states of three-dimensional topological insulators (3D TIs) makes them promising candidates for spintronics applications. Surface potentials which respect time-reversal symmetry can exist at the surface between a 3D TI and the trivial vacuum. These potentials can distort the spin texture of the surface states while retaining their gapless nature. In this work, the effect of all such surface potentials on the spin textures is studied. Since a tunnel magnetoresistance signal carries the information of the spin texture, it is proposed that spin-polarized tunneling of electrons to a 3D TI surface can be used to uniquely identify the surface potentials and quantitatively characterize them.
Surface shape affects the three-dimensional exploratory movements of nocturnal arboreal snakes.
Jayne, Bruce C; Olberding, Jeffrey P; Athreya, Dilip; Riley, Michael A
2012-12-01
Movement and searching behaviors at diverse spatial scales are important for understanding how animals interact with their environment. Although the shapes of branches and the voids in arboreal habitats seem likely to affect searching behaviors, their influence is poorly understood. To gain insights into how both environmental structure and the attributes of an animal may affect movement and searching, we compared the three-dimensional exploratory movements of snakes in the dark on two simulated arboreal surfaces (disc and horizontal cylinder). Most of the exploratory movements of snakes in the dark were a small fraction of the distances they could reach while bridging gaps in the light. The snakes extended farther away from the edge of the supporting surface at the ends of the cylinder than from the sides of the cylinder or from any direction from the surface of the disc. The exploratory movements were not random, and the surface shape and three-dimensional directions had significant interactive effects on how the movements were structured in time. Thus, the physical capacity for reaching did not limit the area that was explored, but the shape of the supporting surface and the orientation relative to gravity did create biased searching patterns. PMID:23052853
NASA Astrophysics Data System (ADS)
Chitsaz, Bijan
The objective of this research was to develop a method for calculating the strain field in three-dimensional objects using electronic speckle pattern interferometry. Two interferometers were utilized for three-dimensional displacement field measurements, and derivation of their optical phase difference relationships are detailed. It was shown that the optical phase difference is dependent on the illumination angle(s) and the wavelength of the illuminating laser. The overall optical system arrangement designed for the three -dimensional displacement field measurements is presented. The Cartesian coordinate displacement components, u, v, or w, at any point on the viewing surface of an object were interpolated by fitting curves through displacement values represented by the fringe centers. The gradients of the displacement curves along the axial and tangential directions were used for strain measurements. A circular cross-section cantilever beam subjected to an eccentric compressive load with known displacement characteristics was used for calibration purposes. The strain fields at a point on the surface of the beam subjected to three different loads were calculated. The reproducibility of the ESPI system was examined by conducting three identical experiments on the cylinder. Each set included assembling and disassembling of the model, disturbing and readjusting of the optical components, and repetitive loading and unloading of the model. The percent difference and standard deviation based on strain values which were obtained from these experiments were calculated and tabulated and compared to theoretical calculations based on beam theory. The system is reported to be highly reproducible with a maximum percent error of 8.2% associated with epsilon_{ theta z}.. The newly developed system was also applied to testing of a human femur with and without femoral prosthesis implantation. The effects of two types of hip implants (press-fit and cemented) on the surface strain
Three-dimensional unsteady lifting surface theory in the subsonic range
NASA Technical Reports Server (NTRS)
Kuessner, H. G.
1985-01-01
The methods of the unsteady lifting surface theory are surveyed. Linearized Euler's equations are simplified by means of a Galileo-Lorentz transformation and a Laplace transformation so that the time and the compressibility of the fluid are limited to two constants. The solutions to this simplified problem are represented as integrals with a differential nucleus; these results in tolerance conditions, for which any exact solution must suffice. It is shown that none of the existing three-dimensional lifting surface theories in subsonic range satisfy these conditions. An oscillating elliptic lifting surface which satisfies the tolerance conditions is calculated through the use of Lame's functions. Numerical examples are calculated for the borderline cases of infinitely stretched elliptic lifting surfaces and of circular lifting surfaces. Out of the harmonic solutions any such temporal changes of the down current are calculated through the use of an inverse Laplace transformation.
NASA Astrophysics Data System (ADS)
Wei, Shiliang; Zhao, Hong; Jing, Juntao
2015-12-01
Surface roughness has considerable influence on its quality and function of products in precision and ultra-precision machining, and the same situation applies to engineering ceramic for rotary ultrasonic grinding machining (RUGM). This paper presents a new parameter, called fractal root mean square deviation, for evaluating engineering ceramic three-dimensional (3D) surface roughness of RUGM. Based on engineering ceramics surface of RUGM is typical isotropic, the mathematical model of fractal root mean square deviation was established, and it possesses double characteristics of absolute measurement and multi-scale. Then validation has been implemented, and fractal root mean square deviation is superior to evaluate engineering ceramic 3D surface roughness with better resolution and sensitivity. Furthermore, the relationship between main factor parameters and fractal root mean square deviation was proposed. The evaluation parameter and the results could be implemented in practice to get higher quality surface.
Fragile surface zero-energy flat bands in three-dimensional chiral superconductors
NASA Astrophysics Data System (ADS)
Kobayashi, Shingo; Tanaka, Yukio; Sato, Masatoshi
2015-12-01
We study surface zero-energy flat bands in three-dimensional chiral superconductors with pz(px+i py) ν -wave pairing symmetry (ν is a nonzero integer), based on topological arguments and tunneling conductance. It is shown that the surface flat bands are fragile against (i) the surface misorientation and (ii) the surface Rashba spin-orbit interaction. The fragility of (i) is specific to chiral SCs, whereas that of (ii) happens for general odd-parity SCs. We demonstrate that these flat-band instabilities vanish or suppress a zero-bias conductance peak in a normal/insulator/superconductor junction, which behavior is clearly different from high-Tc cuprates and noncentrosymmetric superconductors. By calculating the angle-resolved conductance, we also discuss a topological surface state associated with the coexistence of line and point nodes.
Effect of Surface Waviness on Transition in Three-Dimensional Boundary-Layer Flow
NASA Technical Reports Server (NTRS)
Masad, Jamal A.
1996-01-01
The effect of a surface wave on transition in three-dimensional boundary-layer flow over an infinite swept wing was studied. The mean flow computed using interacting boundary-layer theory, and transition was predicted using linear stability theory coupled with the empirical eN method. It was found that decreasing the wave height, sweep angle, or freestream unit Reynolds number, and increasing the freestream Mach number or suction level all stabilized the flow and moved transition onset to downstream locations.
NASA Technical Reports Server (NTRS)
Perucchio, R.; Ingraffea, A. R.
1984-01-01
The establishment of the boundary element method (BEM) as a valid tool for solving problems in structural mechanics and in other fields of applied physics is discussed. The development of an integrated interactive computer graphic system for the application of the BEM to three dimensional problems in elastostatics is described. The integration of interactive computer graphic techniques and the BEM takes place at the preprocessing and postprocessing stages of the analysis process, when, respectively, the data base is generated and the results are interpreted. The interactive computer graphic modeling techniques used for generating and discretizing the boundary surfaces of a solid domain are outlined.
Combined optimal quantization and lossless coding of digital holograms of three-dimensional objects
NASA Astrophysics Data System (ADS)
Shortt, Alison E.; Naughton, Thomas J.; Javidi, Bahram
2006-10-01
Digital holography is an inherently three-dimensional (3D) technique for the capture of real-world objects. Many existing 3D imaging and processing techniques are based on the explicit combination of several 2D perspectives (or light stripes, etc.) through digital image processing. The advantage of recording a hologram is that multiple 2D perspectives can be optically combined in parallel, and in a constant number of steps independent of the hologram size. Although holography and its capabilities have been known for many decades, it is only very recently that digital holography has been practically investigated due to the recent development of megapixel digital sensors with sufficient spatial resolution and dynamic range. The applications of digital holography could include 3D television, virtual reality, and medical imaging. If these applications are realized, compression standards will have to be defined. We outline the techniques that have been proposed to date for the compression of digital hologram data and show that they are comparable to the performance of what in communication theory is known as optimal signal quantization. We adapt the optimal signal quantization technique to complex-valued 2D signals. The technique relies on knowledge of the histograms of real and imaginary values in the digital holograms. Our digital holograms of 3D objects are captured using phase-shift interferometry. We complete the compression procedure by applying lossless techniques to the quantized holographic pixels.
Application of S-transform profilometry in train wheel surface three dimensional measurement
NASA Astrophysics Data System (ADS)
Wang, Haiqing; Zhang, Yu; Li, Jinlong; Hu, Jiayuan
2015-12-01
A three dimensional (3D) measurement method for train wheel surface is proposed based on S-transform profilometry. This method is based on S-transform in fringe analysis. A fringe pattern with a carrier frequency component is projected onto the wheel tread, the deformed fringe patterns caused by the height distribution of wheel surface is recorded as an image, and the fundamental spectrum of S-transform spectra from the image is abstracted by use of weighting filters, then the wrapped phase is obtained by IFFT of the fundamental spectrum. 2D-SRNCP (sorting by reliability following a non-continuous path) phase unwrapping algorithm is used to unwrap phase, which can be used to reconstruct the surface distribution of wheel. Simulation and testing experiment is taken and the result shows that, comparing with light-section method, this method can realize a faster inspection and a higher accuracy measurement of 3D wheel surface.
Barthwal, Sumit; Kim, Young Su; Lim, Si-Hyung
2013-06-15
Superamphiphobic functional Ti foils were fabricated using anodization techniques. By varying the supply voltage and anodization time, a two-step anodization method was used to maximize the contact angle of water and various oils. The morphology of the TiO2 nanotube surface is important to achieve superamphiphobicitiy. The anodized surface maintained good superamphiphobic stability with long-term storage. Furthermore, the wettability properties toward both water and various oils can be easily and reversibly switched from hydrophobic and oleophobic to hydrophilic and oleophilic, respectively, and vice versa via air-plasma treatment and fluorination. The developed simple technique can be applied to any large-area three-dimensional surfaces to fabricate amphiphobic Ti surfaces. PMID:23545242
A three-dimensional parametric mesher with surface boundary-layer capability
NASA Astrophysics Data System (ADS)
Aubry, R.; Karamete, B. K.; Mestreau, E. L.; Dey, S.
2014-08-01
A novel parametric surface meshing technique is presented. Its distinctive feature relies on successive approximations of the CAD geometry through a hierarchical process where geometric information is gathered incrementally. A detailed review of zero- and first-order surface approximations and their impact on parametric surface meshing algorithms is performed. The proposed approach emphasizes the use of three-dimensional information in order to be as independent as possible of the parametrization to overcome limitations of meshing purely in the parametric plane. The presented technique includes semi-structured boundary-layer surface mesh generation which is a critical capability for accurate solutions to flows around geometries that have leading edge features. Numerous examples illustrate the method's robustness and ability to high-quality meshes for complex CAD geometries.
Yan, Hao; Pan, Bing
2014-09-01
A new simultaneous three-dimensional (3D) displacement measurement technique based on the combination of digital holography (DH) and digital imaging correlation (DIC) is proposed. The current DH-based 3D displacement measurement technique needs three sets of DH setups, and only the phase images are utilized in measurements, with all the intensity images discarded. In contrast, the proposed new technique only adopts a single off-axis DH setup. In the proposed technique, the phase images are used to extract out-of-plane displacements, but the intensity images (instead of being discarded) are processed by an intensity correlation algorithm to retrieve in-plane displacement components. Because the proposed technique fully takes advantage of all the information obtained by an off-axis DH without additional optical arrangements, it is simpler and more practical than the existing DH-based 3D displacement measurement technique. Experiments performed on a United States Air Force (USAF) target demonstrate that both the in-plane and out-of-plane displacements can be accurately determined by the proposed technique. PMID:25166100
Image system for three dimensional, 360{degree}, time sequence surface mapping of moving objects
Lu, S.Y.
1998-12-22
A three-dimensional motion camera system comprises a light projector placed between two synchronous video cameras all focused on an object-of-interest. The light projector shines a sharp pattern of vertical lines (Ronchi ruling) on the object-of-interest that appear to be bent differently to each camera by virtue of the surface shape of the object-of-interest and the relative geometry of the cameras, light projector and object-of-interest. Each video frame is captured in a computer memory and analyzed. Since the relative geometry is known and the system pre-calibrated, the unknown three-dimensional shape of the object-of-interest can be solved for by matching the intersections of the projected light lines with orthogonal epipolar lines corresponding to horizontal rows in the video camera frames. A surface reconstruction is made and displayed on a monitor screen. For 360{degree} all around coverage of the object-of-interest, two additional sets of light projectors and corresponding cameras are distributed about 120{degree} apart from one another. 20 figs.
Image system for three dimensional, 360 DEGREE, time sequence surface mapping of moving objects
Lu, Shin-Yee
1998-01-01
A three-dimensional motion camera system comprises a light projector placed between two synchronous video cameras all focused on an object-of-interest. The light projector shines a sharp pattern of vertical lines (Ronchi ruling) on the object-of-interest that appear to be bent differently to each camera by virtue of the surface shape of the object-of-interest and the relative geometry of the cameras, light projector and object-of-interest Each video frame is captured in a computer memory and analyzed. Since the relative geometry is known and the system pre-calibrated, the unknown three-dimensional shape of the object-of-interest can be solved for by matching the intersections of the projected light lines with orthogonal epipolar lines corresponding to horizontal rows in the video camera frames. A surface reconstruction is made and displayed on a monitor screen. For 360.degree. all around coverage of theobject-of-interest, two additional sets of light projectors and corresponding cameras are distributed about 120.degree. apart from one another.
NASA Astrophysics Data System (ADS)
Ghosh, Sankalpa; Mondal, Puja
The surface states of the three dimensional (3D) Topological Insulators are described by two-dimensional (2D) massless dirac equation. A gate voltage induced one dimensional potential barrier on such surface creates a discrete bound state in the forbidden region outside the dirac cone. Even for a single barrier it is shown such bound state can create electrostatic analogue of Shubnikov de Haas oscillation which can be experimentally observed for relatively smaller size samples. However when these surface states are exposed to a periodic arrangement of such gate voltage induced potential barriers, the band structure of the same got nontrivially modified. This is expected to significantly alters the properties of macroscopic system. We also suggest that in suitable limit the system may offer ways to control electron spin electrostatically which may be practically useful Supported by UGC Fellowship (PM) and a UKIERI-UGC Thematic Partnership.
NASA Astrophysics Data System (ADS)
Mondal, Puja; Ghosh, Sankalpa
2015-12-01
The surface states of the three-dimensional (3D) topological insulators are described by a two-dimensional (2D) massless dirac equation. A gate-voltage-induced one-dimensional potential barrier on such surfaces creates a discrete bound state in the forbidden region outside the dirac cone. Even for a single barrier it is shown that such a bound state can create an electrostatic analogue of Shubnikov de Haas oscillation which can be experimentally observed for relatively smaller size samples. However, when these surface states are exposed to a periodic arrangement of such gate-voltage-induced potential barriers, the band structure of the same was significantly modified. This is expected to significantly alter the properties of the macroscopic system. We also suggest that, within suitable limits, the system may offer ways to control electron spin electrostatically, which may be practically useful.
Digital multi-step phase-shifting profilometry for three-dimensional ballscrew surface imaging
NASA Astrophysics Data System (ADS)
Liu, Cheng-Yang; Yen, Tzu-Ping
2016-05-01
A digital multi-step phase-shifting profilometry for three-dimensional (3-D) ballscrew surface imaging is presented. The 3-D digital imaging system is capable of capturing fringe pattern images. The straight fringe patterns generated by software in the computer are projected onto the ballscrew surface by the DLP projector. The distorted fringe patterns are captured by the CCD camera at different detecting directions for reconstruction algorithms. The seven-step phase-shifting algorithm and quality guided path unwrapping algorithm are used to calculate absolute phase at each pixel position. The 3-D calibration method is used to obtain the relationship between the absolute phase map and ballscrew shape. The angular dependence of 3-D shape imaging for ballscrews is analyzed and characterized. The experimental results may provide a novel, fast, and high accuracy imaging system to inspect the surface features of the ballscrew without length limitation for automated optical inspection industry.
Three-dimensional assessment of condylar surface changes and remodeling after orthognathic surgery
Lee, Jung-Hye; Lee, Woo-Jin; Shin, Jae-Myung; Huh, Kyung-Hoe; Yi, Won-Jin; Heo, Min-Suk; Lee, Sam-Sun
2016-01-01
Purpose This study was performed to evaluate condylar surface changes and remodeling after orthognathic surgery using three-dimensional computed tomography (3D CT) imaging, including comparisons between the right and left sides and between the sexes. Materials and Methods Forty patients (20 males and 20 females) who underwent multi-detector CT examinations before and after surgery were selected. Three-dimensional images comprising thousands of points on the condylar surface were obtained before and after surgery. For the quantitative assessment of condylar surface changes, point-to-point (preoperative-to-postoperative) distances were calculated using D processing software. These point-to-point distances were converted to a color map. In order to evaluate the types of condylar remodeling, the condylar head was divided into six areas (anteromedial, anteromiddle, anterolateral, posteromedial, posteromiddle, and posterolateral areas) and each area was classified into three types of condylar remodeling (bone formation, no change, and bone resorption) based on the color map. Additionally, comparative analyses were performed between the right and left sides and according to sex. Results The mean of the average point-to-point distances on condylar surface was 0.11±0.03 mm. Bone resorption occurred more frequently than other types of condylar remodeling, especially in the lateral areas. However, bone formation in the anteromedial area was particularly prominent. No significant difference was found between the right and left condyles, but condylar surface changes in males were significantly larger than in females. Conclusion This study revealed that condylar remodeling exhibited a tendency towards bone resorption, especially in the lateral areas. Condylar surface changes occurred, but were small. PMID:27051636
NASA Astrophysics Data System (ADS)
Pandey, S.; Yuan, X.; Debayle, E.; Priestley, K. F.; Kind, R.; Li, X.
2010-12-01
The collision of the Eurasian plate, Indian plate and Philippine sea plate resulted in the tectonic feature of todays; like mountain ranges, fold belts, sedimentary basins and high plateaus in China and the surrounding region. In the Northern part this region is supposed to get some resistance from the Siberian shield. But the collision of Indian plate has left its major imprints and the consequence of this was the uplift of Himalayan Mountain and Tibetan Plateau. This triple junction scenario is the main cause for many inter and intra-plate earthquake in this region. It is generally agreed that the lithosphere is thick in west China while much of the lithospheric root was lost beneath some cratons in east China. Still it's an open debate whether the lithosphere beneath the Tibetan plateau has doubled its thickness as did the crust above or much of the thickened lithosphere was removed by mantle convection and delamination. In our study we try to determine the three dimensional Sv wave speed and azimuthal anisotropy model by analyzing the vertical component multimode Rayleigh wave seismogram. The data which we used are from broadband stations from in and around China. We construct the three dimensional model in two step procedure. In the first step we use the automated version of the Cara and Leveque [1987] waveform inversion technique in terms of secondary observables for modeling each multimode Rayleigh waveform to determine the path-average mantle Sv wave speed structure. In the second stage we combine the 1-D velocity models in a tomographic inversion to obtain the three dimensional Sv wave speed structure and the azimuthal anisotropy as a function of depth. We have taken a source region specific velocity structure from the three dimensional model 3SMAC to improve the source excitation computation. We analyzed the seismograms using a modified (smoothed) version of PREM for the upper mantle velocity structure both for the reference model used in extracting the
A numerical study of three-dimensional viscous interactions of vortices with a free surface
NASA Astrophysics Data System (ADS)
Dommermuth, D.; Yue, D.
Semi-implicit and explicit numerical methods are developed for the direct simulation of the three-dimensional Navier-Stokes equations with a free surface. The efficiency of a novel multigrid flow solver permits the simulation of three-dimensional flows with free surfaces at low Reynolds and Froude numbers. The numerical schemes are used to study vortex rings and tubes interacting with walls and free surfaces. In the case of vortex rings interacting with a no-slip wall observations of the formation of secondary and tertiary vortex rings agree qualitatively with experimental measurements. When a free surface is present, the results are sensitive to the Froude number. For sufficiently low Froude numbers, the free surface behaves like a free-slip wall, which agrees qualitatively with experimental observations of vortex rings interacting with clean free surfaces. At intermediate Froude numbers, the normal incidence of a vortex ring with a clean free surface results in the formation of secondary vortex rings. Numerical studies of vortex tubes interacting with free surfaces show two possible mechanisms for the reconnection of vorticity with a free surface including primary and secondary vorticity reconnections. One type of primary vorticity reconnection should result in a cusp pattern on the free surface and secondary vorticity reconnections should manifest themselves as paired dimples on the free surface. The essential stages of the reconnection of secondary vorticity with the free surface are as follows: generation of helical vortex sheets by the primary vortex tube, stripping of the helical vortex sheets due to self-induced straining flows, attachment of the helical vortex sheets to the separated free-surface boundary layer, wrapping of U-shaped vortices around the primary vortex tube, feeding of boundary-layer vorticity into the U-vortices, and reconnection of U-vortices with the free surface. We provide evidence which suggests that the striations that may be observed
Three-dimensional surface reconstruction for cartridge cases using photometric stereo.
Sakarya, Ufuk; Leloğlu, Uğur Murat; Tunali, Erol
2008-03-01
In forensic science, automated firearms identification is an important and yet unsolved problem. On the way to the solution, one of the most important phases is data acquisition. To be able to identify firearms in a reliable way, all the striated and impressed marks on metallic surfaces of cartridge cases should be visible. But two-dimensional images of cartridge cases are very sensitive to the type and direction of the light source(s). Depending on illumination conditions, the images of marks change drastically and sometimes they simply disappear. But, if the three-dimensional (3D) topography of the surface is obtained, the geometry of the marks, which is independent of the illumination, is available. Thus, by providing illumination independent features that can be used for automated matching, 3D data have the potential to make automated matching much reliable. In the literature on data acquisition for automated firearms identification, a few different ways of three-dimensional surface extraction are described, like laser interferometry or laser profilometry. This study presents a real life application of another method, photometric stereo, for the acquisition of 3D topographic data for cartridge cases, which is the one used in BALISTIKA Ballistics Image Analysis and Recognition System. In order to construct 3D topographic data, first of all, two-dimensional images were acquired using a specially designed set-up. After the images were calibrated radiometrically, photometric stereo method was applied. In order to minimize the low-frequency errors in the final surface, a surface-fitting algorithm was used. The method uses low-cost equipment and image acquisition is not time-consuming. Results were compared to interferometric measurement values for error assessment. PMID:17703904
Wei, Bo; Yao, Qingqiang; Guo, Yang; Mao, Fengyong; Liu, Shuai; Xu, Yan; Wang, Liming
2015-08-01
The goal of this study was to investigate the chondrogenic potential of three-dimensional polycaprolactone-hydroxyapatite (PCL-HA) scaffolds loaded with bone marrow cells in vitro and the effect of PCL-HA scaffolds on osteochondral repair in vivo. Here, bone marrow was added to the prepared PCL-HA scaffolds and cultured in chondrogenic medium for 10 weeks. Osteochondral defects were created in the trochlear groove of 29 knees in 17 New Zealand white rabbits, which were then divided into four groups that underwent: implantation of PCL-HA scaffolds (left knee, n = 17; Group 1), microfracture (right knee, n = 6; Group 2), autologous osteochondral transplantation (right knee, n = 6; Group 3), and no treatment (right knee, n = 5; Control). Extracellular matrix produced by bone marrow cells covered the surface and filled the pores of PCL-HA scaffolds after 10 weeks in culture. Moreover, many cell-laden cartilage lacunae were observed, and cartilage matrix was concentrated in the PCL-HA scaffolds. After a 12-week repair period, Group 1 showed excellent vertical and lateral integration with host bone, but incomplete cartilage regeneration and matrix accumulation. An uneven surface of regenerated cartilage and reduced distribution of cartilage matrix were observed in Group 2. In addition, abnormal bone growth and unstable integration between repaired and host tissues were detected. For Group 3, the integration between transplanted and host cartilage was interrupted. Our findings indicate that the PCL-HA scaffolds loaded with bone marrow cells improved chondrogenesis in vitro and implantation of PCL-HA scaffolds for osteochondral repairenhanced integration with host bone. However, cartilage regeneration remained unsatisfactory. The addition of trophic factors or the use of precultured cell-PCL-HA constructs for accelerated osteochondral repair requires further investigation. PMID:25766036
NASA Astrophysics Data System (ADS)
Martin-Jimenez, Daniel; Chacon, Enrique; Tarazona, Pedro; Garcia, Ricardo
2016-07-01
Interfacial liquid layers play a central role in a variety of phenomena ranging from friction to molecular recognition. Liquids near a solid surface form an interfacial layer where the molecular structure is different from that of the bulk. Here we report atomic resolution three-dimensional images of electrolyte solutions near a mica surface that demonstrate the existence of three types of interfacial structures. At low concentrations (0.01-1 M), cations are adsorbed onto the mica. The cation layer is topped by a few hydration layers. At higher concentrations, the interfacial layer extends several nanometres into the liquid. It involves the alternation of cation and anion planes. Fluid Density Functional calculations show that water molecules are a critical factor for stabilizing the structure of the interfacial layer. The interfacial layer stabilizes a crystal-like structure compatible with liquid-like ion and solvent mobilities. At saturation, some ions precipitate and small crystals are formed on the mica.
Enhanced three-dimensional stochastic adjustment for combined volcano geodetic networks
NASA Astrophysics Data System (ADS)
Del Potro, R.; Muller, C.
2009-12-01
Volcano geodesy is unquestionably a necessary technique in studies of physical volcanology and for eruption early warning systems. However, as every volcano geodesist knows, obtaining measurements of the required resolution using traditional campaigns and techniques is time consuming and requires a large manpower. Moreover, most volcano geodetic networks worldwide use a combination of data from traditional techniques; levelling, electronic distance measurements (EDM), triangulation and Global Navigation Satellite Systems (GNSS) but, in most cases, these data are surveyed, analysed and adjusted independently. This then leaves it to the authors’ criteria to decide which technique renders the most realistic results in each case. Herein we present a way of solving the problem of inter-methodology data integration in a cost-effective manner following a methodology were all the geodetic data of a redundant, combined network (e.g. surveyed by GNSS, levelling, distance, angular data, INSAR, extensometers, etc.) is adjusted stochastically within a single three-dimensional referential frame. The adjustment methodology is based on the least mean square method and links the data with its geometrical component providing combined, precise, three-dimensional, displacement vectors, relative to external reference points as well as stochastically-quantified, benchmark-specific, uncertainty ellipsoids. Three steps in the adjustment allow identifying, and hence dismissing, flagrant measurement errors (antenna height, atmospheric effects, etc.), checking the consistency of external reference points and a final adjustment of the data. Moreover, since the statistical indicators can be obtained from expected uncertainties in the measurements of the different geodetic techniques used (i.e. independent of the measured data), it is possible to run a priori simulations of a geodetic network in order to constrain its resolution, and reduce logistics, before the network is even built. In this
NASA Astrophysics Data System (ADS)
Xu, Yang; Miotkowski, Ireneusz; Chen, Yong; Yong P. Chen's Group in Purdue Team; Chih-Kang Shih's Group in UT-Austin Collaboration; M. Zahid Hasan's Group in Princeton Collaboration
2015-03-01
A three-dimensional (3D) topological insulator (TI) is a novel quantum matter with a gapped insulating bulk yet a conducting surface hosting topologically-protected gapless surface states of Dirac fermions. One of the most distinct electronic transport signatures predicted for such topological surface states (TSS) is a half-integer quantum Hall effect (QHE) in a magnetic field. We have observed well-developed QHE arising from TSS in an intrinsic TI of BiSbTeSe2. Our samples can exhibit surface dominated conduction even close to room temperature, while the bulk conduction is negligible. At low temperatures and high perpendicular magnetic fields, the Hall conductance shows well quantized integer plateaux in exfoliated flake devices on SiO2 / Si substrates, where the top and bottom surface each contributing a half integer e2 / h Hall conductance, accompanied by vanishing longitudinal resistance. We have also studied dual-gated devices where both the top and bottom surfaces can be independently gated. Such intrinsic 3D TI materials exhibiting no measurable bulk conduction and well-developed surface state QHE pave the way for further applications of topological quantum electronics. DARPA MESO program (Grant N66001-11-1-4107).
The Application of Three-Dimensional Surface Imaging System in Plastic and Reconstructive Surgery.
Li, Yanqi; Yang, Xin; Li, Dong
2016-02-01
Three-dimensional (3D) surface imaging system has gained popularity worldwide in clinical application. Unlike computed tomography and magnetic resonance imaging, it has the ability to capture 3D images with both shape and texture information. This feature has made it quite useful for plastic surgeons. This review article is mainly focusing on demonstrating the current status and analyzing the future of the application of 3D surface imaging systems in plastic and reconstructive surgery.Currently, 3D surface imaging system is mainly used in plastic and reconstructive surgery to help improve the reliability of surgical planning and assessing surgical outcome objectively. There have already been reports of its using on plastic and reconstructive surgery from head to toe. Studies on facial aging process, online applications development, and so on, have also been done through the use of 3D surface imaging system.Because different types of 3D surface imaging devices have their own advantages and disadvantages, a basic knowledge of their features is required and careful thought should be taken to choose the one that best fits a surgeon's demand.In the future, by integrating with other imaging tools and the 3D printing technology, 3D surface imaging system will play an important role in individualized surgical planning, implants production, meticulous surgical simulation, operative techniques training, and patient education. PMID:27015345
NASA Astrophysics Data System (ADS)
Yang, Xinyan; Li, Yuguo
2013-11-01
The Model for Urban Surface Temperature, a three-dimensional approach, is developed for a realistically complex city with considerations of the energy exchange processes at the urban surface. The discrete transfer method and Gebhart absorption factor method are used for the shape factor estimation and multiple reflection calculation, respectively. The surface energy balance model is evaluated against existing field measurements that pertain to idealized urban geometry. It performs well in terms of predicting surface temperature and heat fluxes by allowing for detailed urban surface properties and meteorological conditions. The compressed row storage scheme is applied to calculate the transfer of surface thermal radiation, which dramatically reduces the computational requirements. This strategy permits the rigorous consideration of multiple reflections in a realistic urban area with hundreds of buildings. The result illustrates that considering only the first reflection is a good approach when the urban area is comprised of typical urban materials, e.g. materials with high emissivity and low albedo, because relatively accurate computational results can be obtained rapidly by avoiding the multiple reflection calculation.
Small-molecule labeling of live cell surfaces for three-dimensional super-resolution microscopy.
Lee, Marissa K; Rai, Prabin; Williams, Jarrod; Twieg, Robert J; Moerner, W E
2014-10-01
Precise imaging of the cell surface of fluorescently labeled bacteria requires super-resolution methods because the size-scale of these cells is on the order of the diffraction limit. In this work, we present a photocontrollable small-molecule rhodamine spirolactam emitter suitable for non-toxic and specific labeling of the outer surface of cells for three-dimensional (3D) super-resolution (SR) imaging. Conventional rhodamine spirolactams photoswitch to the emitting form with UV light; however, these wavelengths can damage cells. We extended photoswitching to visible wavelengths >400 nm by iterative synthesis and spectroscopic characterization to optimize the substitution on the spirolactam. Further, an N-hydroxysuccinimide-functionalized derivative enabled covalent labeling of amines on the surface of live Caulobacter crescentus cells. Resulting 3D SR reconstructions of the labeled cell surface reveal uniform and specific sampling with thousands of localizations per cell and excellent localization precision in x, y, and z. The distribution of cell stalk lengths (a sub-diffraction-sized cellular structure) was quantified for a mixed population of cells. Pulse-chase experiments identified sites of cell surface growth. Covalent labeling with the optimized rhodamine spirolactam label provides a general strategy to study the surfaces of living cells with high specificity and resolution down to 10-20 nm. PMID:25222297
Small-Molecule Labeling of Live Cell Surfaces for Three-Dimensional Super-Resolution Microscopy
2015-01-01
Precise imaging of the cell surface of fluorescently labeled bacteria requires super-resolution methods because the size-scale of these cells is on the order of the diffraction limit. In this work, we present a photocontrollable small-molecule rhodamine spirolactam emitter suitable for non-toxic and specific labeling of the outer surface of cells for three-dimensional (3D) super-resolution (SR) imaging. Conventional rhodamine spirolactams photoswitch to the emitting form with UV light; however, these wavelengths can damage cells. We extended photoswitching to visible wavelengths >400 nm by iterative synthesis and spectroscopic characterization to optimize the substitution on the spirolactam. Further, an N-hydroxysuccinimide-functionalized derivative enabled covalent labeling of amines on the surface of live Caulobacter crescentus cells. Resulting 3D SR reconstructions of the labeled cell surface reveal uniform and specific sampling with thousands of localizations per cell and excellent localization precision in x, y, and z. The distribution of cell stalk lengths (a sub-diffraction-sized cellular structure) was quantified for a mixed population of cells. Pulse-chase experiments identified sites of cell surface growth. Covalent labeling with the optimized rhodamine spirolactam label provides a general strategy to study the surfaces of living cells with high specificity and resolution down to 10–20 nm. PMID:25222297
Tamjid, Elnaz; Simchi, Arash; Dunlop, John W C; Fratzl, Peter; Bagheri, Reza; Vossoughi, Manouchehr
2013-10-01
Controlling topographic features at all length scales is of great importance for the interaction of cells with tissue regenerative materials. We utilized an indirect three-dimensional printing method to fabricate polymeric scaffolds with pre-defined and controlled external and internal architecture that had an interconnected structure with macro- (400-500 μm) and micro- (∼25 μm) porosity. Polycaprolactone (PCL) was used as model system to study the kinetics of tissue growth within porous scaffolds. The surface of the scaffolds was decorated with TiO2 and bioactive glass (BG) nanoparticles to the better match to nanoarchitecture of extracellular matrix (ECM). Micrometric BG particles were also used to reveal the effect of particle size on the cell behavior. Observation of tissue growth and enzyme activity on two-dimensional (2D) films and three-dimensional (3D) scaffolds showed effects of nanoparticle inclusion and of surface curvature on the cellular adhesion, proliferation, and kinetics of preosteoblastic cells (MC3T3-E1) tissue growth into the pore channels. It was found that the presence of nanoparticles in the substrate impaired cellular adhesion and proliferation in 3D structures. Evaluation of alkaline phosphate activity showed that the presence of the hard particles affects differentiation of the cells on 2D films. Notwithstanding, the effect of particles on cell differentiation was not as strong as that seen by the curvature of the substrate. We observed different effects of nanofeatures on 2D structures with those of 3D scaffolds, which influence the cell proliferation and differentiation for non-load-bearing applications in bone regenerative medicine. PMID:23463703
Imaging three-dimensional surface objects with submolecular resolution by atomic force microscopy.
Moreno, César; Stetsovych, Oleksandr; Shimizu, Tomoko K; Custance, Oscar
2015-04-01
Submolecular imaging by atomic force microscopy (AFM) has recently been established as a stunning technique to reveal the chemical structure of unknown molecules, to characterize intramolecular charge distributions and bond ordering, as well as to study chemical transformations and intermolecular interactions. So far, most of these feats were achieved on planar molecular systems because high-resolution imaging of three-dimensional (3D) surface structures with AFM remains challenging. Here we present a method for high-resolution imaging of nonplanar molecules and 3D surface systems using AFM with silicon cantilevers as force sensors. We demonstrate this method by resolving the step-edges of the (101) anatase surface at the atomic scale by simultaneously visualizing the structure of a pentacene molecule together with the atomic positions of the substrate and by resolving the contour and probe-surface force field on a C60 molecule with intramolecular resolution. The method reported here holds substantial promise for the study of 3D surface systems such as nanotubes, clusters, nanoparticles, polymers, and biomolecules using AFM with high resolution. PMID:25756297
Three-dimensional evaluation of surface roughness of resin composites after finishing and polishing
Nair, Veena S; Sainudeen, Shan; Padmanabhan, Prabeesh; Vijayashankar, L V; Sujathan, Unu; Pillai, Rajesh
2016-01-01
Aim: This study aims to investigate the effects of finishing and polishing procedures on four novel resin composites using three-dimensional optical profilometer. Materials and Methods: Four composites classified according to their filler size, were selected: Filtek™ Z350 XT/Nanofill (3M™ ESPE™), Esthet-X HD/Hybrid (Dentsply Caulk), Te Econom/Microfill (Ivoclar Vivadent®), Tetric EvoCeram® /Nanohybrid (Ivoclar Vivadent®). Composite specimens were made in Plexiglass mold and polished with Soflex (3M ESPE), Enhance + Pogo (Dentsply Caulk). Both the systems were used according to the manufacturers’ instructions, and the polished surfaces were assessed with an optical profilometer. Statistical Analysis Used: Kruskal-Wallis test and further pairwise comparison were performed by Mann-Whitney test. Results: The smoothest surfaces for all the resin composites tested were obtained from the Mylar strip; statistically significant differences were observed among them (P = 0.001). The order of composites was ranked from the lowest to highest surface roughness; Filtek Z350 XT < Te Econom < Tetric EvoCeram < Esthet XHD. Pairwise multiple comparison with Mann-Whitney test showed Filtek Z350 to have the smoothest surface and the least with Teric EvoCeram. Among the polishing systems, Soflex showed the smoothest surface and was significantly different from Pogo (P = 0.046). Conclusions: The effectiveness of the polishing systems seems to be dependent on the material used, treatment modality and also on the filler particle size. PMID:26957802
Towards three-dimensional Weyl-surface semimetals in graphene networks
NASA Astrophysics Data System (ADS)
Zhong, Chengyong; Chen, Yuanping; Xie, Yuee; Yang, Shengyuan A.; Cohen, Marvin L.; Zhang, S. B.
2016-03-01
Graphene as a two-dimensional topological semimetal has attracted much attention for its outstanding properties. In contrast, three-dimensional (3D) topological semimetals of carbon are still rare. Searching for such materials with salient physics has become a new direction in carbon research. Here, using first-principles calculations and tight-binding modeling, we propose a new class of Weyl semimetals based on three types of 3D graphene networks. In the band structures of these materials, two flat Weyl surfaces appear in the Brillouin zone, which straddle the Fermi level and are robust against external strain. Their unique atomic and electronic structures enable applications in correlated electronics, as well as in energy storage, molecular sieves, and catalysis. When the networks are cut, the resulting slabs and nanowires remain semimetallic with Weyl lines and points at the Fermi surfaces, respectively. Between the Weyl lines, flat surface bands emerge with possible strong magnetism. The robustness of these structures can be traced back to a bulk topological invariant, ensured by the sublattice symmetry, and to the one-dimensional Weyl semimetal behavior of the zigzag carbon chain.Graphene as a two-dimensional topological semimetal has attracted much attention for its outstanding properties. In contrast, three-dimensional (3D) topological semimetals of carbon are still rare. Searching for such materials with salient physics has become a new direction in carbon research. Here, using first-principles calculations and tight-binding modeling, we propose a new class of Weyl semimetals based on three types of 3D graphene networks. In the band structures of these materials, two flat Weyl surfaces appear in the Brillouin zone, which straddle the Fermi level and are robust against external strain. Their unique atomic and electronic structures enable applications in correlated electronics, as well as in energy storage, molecular sieves, and catalysis. When the networks
A spectral formalism for computing three-dimensional deformations due to surface loads. 1: Theory
NASA Technical Reports Server (NTRS)
Mitrovica, J. X.; Davis, J. L.; Shapiro, I. I.
1994-01-01
We outline a complete spectral formalism for computing high spatial resolution three-dimensional deformations arising from the surface mass loading of a spherically symmetric planet. The main advantages of the formalism are that all surface mass loads are always described using a consistent mathematical representation and that calculations of deformation fields for various spatial resolutions can be performed by simpley altering the spherical harmonic degree truncation level of the procedure. The latter may be important when incorporating improved observational constraints on a particular surface mass load, when considering potential errors in the computed field associated with mass loading having a spatial scale unresolved by the observational constraints, or when treating a number of global surface mass loads constrained with different spatial resolutions. The advantages do not extend to traditional 'Green's function' approaches which involve surface element discretizations of the global mass loads. Another advantage of the spectral formalism, over the Green's function approach, is that a posteriori analyses of the computed deformation fields are easily performed. In developing the spectral formalism, we consider specific cases where the Earth's mantle is assumed to respond as an elastic, slightly anelastic, or linear viscoelastic medium. In the case of an elastic or slightly anelastic mantle rheology the spectral response equations incorporate frequency dependent Love numbers. The formalism can therefore be used, for example, to compute the potentially resonant deformational response associated with the free core nutation and Chandler wobble eigenfunctions. For completeness, the spectral response equations include both body forces, as arise from the gravitational attraction of the Sun and the Moon, and surface mass loads. In either case, and for both elastic and anelastic mantle rheologies, we outline a pseudo-spectral technique for computing the ocean
NASA Astrophysics Data System (ADS)
Neff, Brian J.; Cain, Stephen C.
2012-05-01
The goal of this work is to develop an algorithm to enhance the utility of three-dimensional (3-D) FLASH laser radar sensors through accurate ranging to multiple surfaces per image pixel while minimizing the effects of diffraction. With this algorithm it will be possible to realize numerous enhancements over both traditional Gaussian mixture modeling and single-surface range estimation. While traditional Gaussian mixture modeling can effectively model the received pulse, we know that its shape is likely altered by optical aberrations from the imaging system and the medium through which it is imaging. Additionally, only identifying a single surface per pulse may result in the loss of valuable information about partially obscured surfaces. This algorithm enables multisurface ranging of an entire image with a single laser pulse. Ultimately, improvements realized through this new ranging algorithm when coupled with various other techniques may make 3-D FLASH LADAR more suitable for remote sensing applications. Simulation examples show that the multisurface ranging algorithm derived in this work improves range estimation over standard Gaussian mixture modeling and frame-by-frame deconvolution using the Richardson-Lucy algorithm by up to 91% and 70% respectively.
NASA Astrophysics Data System (ADS)
Okada, Yoshinori
2014-03-01
Three dimensional topological insulators (TIs) are a new class of material possessing topologically protected spin-polarized Dirac fermions on their surface. This new material has gathered much attention because of its great potential for realizing novel phenomena that are important for both fundamentals and applications. 3D topological insulators have been extensively probed by surface sensitive tools such as ARPES and spectroscopic imaging scanning tunneling microscopy (STM). In this talk, we will especially focus on STM measurements of Pb1-xSnxSe. This material belongs to a recently discovered new category of topological insulators called topological crystalline insulators (TCIs). In TCIs, topology and crystal symmetry intertwine to create surface states with a unique set of characteristics different from conventional 3D TIs. We have discovered broken mirror symmetry driven states that coexist with massless Dirac electrons in different regions of momentum space. Our findings experimentally demonstrate the unique tunability of surface Dirac electrons which is promising for the future realization of novel electronic states within TCIs. Current address: WPI-AIMR Tohoku University, Japan.
Analytical real-time measurement of a three-dimensional weld pool surface
NASA Astrophysics Data System (ADS)
Zhang, WeiJie; Wang, XueWu; Zhang, YuMing
2013-11-01
The ability to observe and measure weld pool surfaces in real-time is the core of the foundation for next generation intelligent welding that can partially imitate skilled welders who observe the weld pool to acquire information on the welding process. This study aims at the real-time measurement of the specular three-dimensional (3D) weld pool surface under a strong arc in gas tungsten arc welding (GTAW). An innovative vision system is utilized in this study to project a dot-matrix laser pattern on the specular weld pool surface. Its reflection from the surface is intercepted at a distance from the arc by a diffuse plane. The intercepted laser dots illuminate this plane producing an image showing the reflection pattern. The deformation of this reflection pattern from the projected pattern (e.g. the dot matrix) is used to derive the 3D shape of the reflection surface, i.e., the weld pool surface. Based on careful analysis, the underlying reconstruction problem is formulated mathematically. An analytic solution is proposed to solve this formulated problem resulting in the weld pool surface being reconstructed on average in 3.04 ms during welding experiments. A vision-based monitoring system is thus established to measure the weld pool surface in GTAW in real-time. In order to verify the effectiveness of the proposed reconstruction algorithm, first numerical simulation is conducted. The proposed algorithm is then tested on a spherical convex mirror with a priori knowledge of its geometry. The detailed analysis of the measurement error validates the accuracy of the proposed algorithm. Results from the real-time experiments verify the robustness of the proposed reconstruction algorithm.
Measurement and characterization of three-dimensional microstructures on precision roller surfaces
NASA Astrophysics Data System (ADS)
Kong, L. B.; Cheung, C. F.; Lee, W. B.; To, S.; Ren, M. J.
2016-01-01
Precision roller with microstructures is the key tooling component in the precision embossing by roller process such as Roll-to-Roll to manufacture optical plastic plates or films with three dimensional (3D)-microstructures. Measurement and analysis of 3D-microstructures on a precision roller is essential before the embossing process is being undertaken to ensure the quality of the embossed surfaces. Different from 3D-microstructures on a planar surface, it is difficult to measure and characterize the 3D-microstructures on the cylindrical surface of a precision roller due to the geometrical complexity of such integrated surfaces such as V-groove microstructures on a cylindrical surface. This paper presents a study of method and algorithms for the measurement and characterization of 3D-microstructures on a precision roller surface. A feature-based characterization method (FBCM) is proposed to analyze the V-groove microstructures. In this method, a normal template is generated based on the design specifications, and the measured data is fitted with the feature points. Hence alignment and matching of the measured data to the normal template based on the derived feature points are undertaken. After that the V-groove is characterized by some feature parameters such as pitch, depth, angle of the V-grooves. The method also provides an approach for the analysis of burs generated during the machining of Vgroove microstructures. A precision roller with V-groove microstructures has been machined by a Four-axis ultraprecision machine and the machined surface is measured by a contact measuring instrument. The measured data are then characterized and analyzed by the proposed FBCM. The results are presented and discussed, and they indicate the dominant and regular machining errors that are involved in the machining of the V-groove microstructures on roller surfaces.
Three-dimensional surface topography acquisition and analysis for firearm identification.
Senin, Nicola; Groppetti, Roberto; Garofano, Luciano; Fratini, Paolo; Pierni, Michele
2006-03-01
In the last decade, computer-based systems for the comparison of microscopic firearms evidence have been the subject of considerable research work because of their expected capability of supporting the firearms examiner through the automated analysis of large amounts of evidence. The Integrated Ballistics Identification System, which is based on a two-dimensional representation of the specimen surface, has been widely adopted in forensic laboratories worldwide. More recently, some attempts to develop systems based on three-dimensional (3D) representations of the specimen surface have been made, both in the literature and as industrial products, such as BulletTRAX-3D, but fundamental limitations in achieving fully automated identification remain. This work analyzes the advantages and disadvantages of a 3D-based approach by proposing an approach and a prototype system for firearms evidence comparison that is based on the acquisition and analysis of the 3D surface topography of specimens, with particular reference to cartridge cases. The concept of 3D virtual comparison microscope is introduced, whose purpose is not to provide fully automated identification, but to show how the availability of 3D shape information can provide a whole new set of verification means, some of them being described and discussed in this work, specifically, visual enhancement tools and quantitative measurement of shape properties, for supporting, not replacing, the firearm examiner in reaching the final decision. PMID:16566761
Three-dimensional surface reconstruction and panoramic optical mapping of large hearts.
Kay, Matthew W; Amison, Philip M; Rogers, Jack M
2004-07-01
Optical mapping of electrical activity from the surface of the heart is a powerful tool for studying complex arrhythmias. However, a limitation of traditional optical mapping is that the mapped region is restricted to the field of view of the sensor, which makes it difficult to track electrical waves as they drift in and out of view. To address this, we developed an optical system that panoramically maps epicardial electrical activity in three dimensions. The system was engineered to accomodate hearts comparable in size to human hearts. It is comprised of a surface scanner that measures epicardial geometry and a panoramic fluorescence imaging system that records electrical activity. Custom software texture maps the electrical data onto a reconstructed epicardial surface. The result is a high resolution, spatially contiguous, mapping dataset. In addition, the three-dimensional positions of the recording sites are known, making it possible to accurately measure parameters that require geometric information, such as propagation velocity. In this paper, we describe the system and demonstrate it by mapping a swine heart. PMID:15248538
Half-filled Landau level, topological insulator surfaces, and three-dimensional quantum spin liquids
NASA Astrophysics Data System (ADS)
Wang, Chong; Senthil, T.
2016-02-01
We synthesize and partly review recent developments relating the physics of the half-filled Landau level in two dimensions to correlated surface states of topological insulators in three dimensions. The latter are in turn related to the physics of certain three-dimensional quantum spin liquid states. The resulting insights provide an interesting answer to the old question of how particle-hole symmetry is realized in composite fermion liquids. Specifically the metallic state at filling ν =1/2 —described originally in pioneering work by Halperin, Lee, and Read as a liquid of composite fermions—was proposed recently by Son to be described by a particle-hole symmetric effective field theory distinct from that in the prior literature. We show how the relation to topological insulator surface states leads to a physical understanding of the correctness of this proposal. We develop a simple picture of the particle-hole symmetric composite fermion through a modification of older pictures as electrically neutral "dipolar" particles. We revisit the phenomenology of composite fermi liquids (with or without particle-hole symmetry), and show that their heat/electrical transport dramatically violates the conventional Wiedemann-Franz law but satisfies a modified one. We also discuss the implications of these insights for finding physical realizations of correlated topological insulator surfaces.
Towards three-dimensional Weyl-surface semimetals in graphene networks.
Zhong, Chengyong; Chen, Yuanping; Xie, Yuee; Yang, Shengyuan A; Cohen, Marvin L; Zhang, S B
2016-04-01
Graphene as a two-dimensional topological semimetal has attracted much attention for its outstanding properties. In contrast, three-dimensional (3D) topological semimetals of carbon are still rare. Searching for such materials with salient physics has become a new direction in carbon research. Here, using first-principles calculations and tight-binding modeling, we propose a new class of Weyl semimetals based on three types of 3D graphene networks. In the band structures of these materials, two flat Weyl surfaces appear in the Brillouin zone, which straddle the Fermi level and are robust against external strain. Their unique atomic and electronic structures enable applications in correlated electronics, as well as in energy storage, molecular sieves, and catalysis. When the networks are cut, the resulting slabs and nanowires remain semimetallic with Weyl lines and points at the Fermi surfaces, respectively. Between the Weyl lines, flat surface bands emerge with possible strong magnetism. The robustness of these structures can be traced back to a bulk topological invariant, ensured by the sublattice symmetry, and to the one-dimensional Weyl semimetal behavior of the zigzag carbon chain. PMID:26971563
Surface roughness and three-dimensional heat conduction in thermophysical models
NASA Astrophysics Data System (ADS)
Davidsson, Björn J. R.; Rickman, Hans
2014-11-01
A thermophysical model is presented that considers surface roughness, cast shadows, multiple or single scattering of radiation, visual and thermal infrared self heating, as well as heat conduction in one or three dimensions. The code is suitable for calculating infrared spectral energy distributions for spatially resolved or unresolved minor Solar System bodies without significant atmospheres or sublimation, such as the Moon, Mercury, asteroids, irregular satellites or inactive regions on comet nuclei. It is here used to explore the effects of surface roughness on spatial scales small enough for heat conduction to erase lateral temperature gradients. Analytically derived corrections to one-dimensional models that reproduce the results of three-dimensional modeling are presented. We find that the temperature of terrains with such small-scale roughness is identical to that of smooth surfaces for certain types of topographies and non-scattering material. However, systematic differences between smooth and rough terrains are found for scattering materials, or topographies with prominent positive relief. Contrary to common beliefs, the roughness on small spatial scales may therefore affect the thermal emission of Solar System bodies.
Zhang, Xiao-Lei; Zhang, Jie; Fan, Tuo; Ren, Wen-Jie; Lai, Chun-Hong
2014-09-01
In order to make surface-enhanced Raman scattering (SERS) substrates contained more "hot spots" in a three-dimensional (3D) focal volume, and can be adsorbed more probe molecules and metal nanoparticles, to obtain stronger Raman spectral signal, a new structure based on vertically aligned carbon nanotubes (CNTs) coated by Ag nanoparticles for surface Raman enhancement is presented. The vertically aligned CNTs are synthesized by chemical vapor deposition (CVD). A silver film is first deposited on the vertically aligned CNTs by magnetron sputtering. The samples are then annealed at different temperature to cause the different size silver nanoparticles to coat on the surface and sidewalls of vertically aligned CNTs. The result of scanning electron microscopy(SEM) shows that Ag nanoparticles are attached onto the sidewalls and tips of the vertically aligned CNTs, as the annealing temperature is different , pitch size, morphology and space between the silver nanoparticles is vary. Rhodamine 6G is served as the probe analyte. Raman spectrum measurement indicates that: the higher the concentration of R6G, the stronger the Raman intensity, but R6G concentration increase with the enhanced Raman intensity varies nonlinearly; when annealing temperature is 450 °C, the average size of silver nanoparticles is about 100 to 120 nm, while annealing temperature is 400 °C, the average size is about 70 nm, and the Raman intensity of 450 °C is superior to the annealing temperature that of 400 °C and 350 °C. PMID:25532342
Soon, C F; Thong, K T; Tee, K S; Ismail, A B; Denyer, M; Ahmad, M K; Kong, Y H; Vyomesh, P; Cheong, S C
2016-01-01
We describe a new scaffold-free three-dimensional (3D) cell culture model using cholesteryl ester based lyotropic liquid crystal (LC) substrates. Keratinocytes were deposited randomly on the LC surface where they self-assembled into 3D microtissues or keratinospheroids. The cell density required to form spheroids was optimized. We investigated cell viability using dead/live cell assays. The adhesion characteristics of cells within the microtissues were determined using histological sectioning and immunofluorescence staining. Fourier transform infrared spectroscopy (FTIR) was used to characterize the biochemistry of the keratinospheroids. We found that both cells and microtissues could migrate on the LC surface. The viability study indicated approximately 80% viability of cells in the microtissues up to 20 days of culture. Strong intercellular adhesion was observed in the stratification of the multi-layered microspheroids using field emission-scanning electron microscopy (FE-SEM) and histochemical staining. The cytoskeleton and vinculins of the cells in the microtissues were expressed diffusely, but the microtissues were enriched with lipids and nucleic acids, which indicates close resemblance to the conditions in vivo. The basic 3D culture model based on LC may be used for cell and microtissue migration studies in response to cytochemical treatment. PMID:27008034
Cinematic three-dimensional surface display of cardiac blood pool tomography
Honda, N.; Machida, K.; Takishima, T.; Mamiya, T.; Takahashi, T.; Kamano, T.; Tamaki, S.; Ban, R. )
1991-02-01
A method of three-dimensional cinematic display (3D cine) of cardiac blood pool tomography is described. ECG-gated transaxial blood pool imaging was obtained from a set of projection images that were collected from 32 images with 10 ECG-gated images per projection during a 180 degrees arc of a rotating gamma camera. A surface contour of the blood pool was determined by a set of isocount lines (40-55% of the maximum pixel counts) of the transaxial images. 3D cine was made by a depth-shading method, in which brightness of a given point on the contour was set proportional to the distance between the viewing plane and the point and to the incident angle formed by the viewing line and the surface of the point. In 15 patients, 3D cine showed hypokinesia, akinesia, dyskinesia, ventricular aneurysm, and opposite motions of the atria and ventricles. Diagnoses of left ventricular motion by 3D cine agreed well with those by echocardiography and contrast left ventriculography.
Martin-Jimenez, Daniel; Chacon, Enrique; Tarazona, Pedro; Garcia, Ricardo
2016-01-01
Interfacial liquid layers play a central role in a variety of phenomena ranging from friction to molecular recognition. Liquids near a solid surface form an interfacial layer where the molecular structure is different from that of the bulk. Here we report atomic resolution three-dimensional images of electrolyte solutions near a mica surface that demonstrate the existence of three types of interfacial structures. At low concentrations (0.01–1 M), cations are adsorbed onto the mica. The cation layer is topped by a few hydration layers. At higher concentrations, the interfacial layer extends several nanometres into the liquid. It involves the alternation of cation and anion planes. Fluid Density Functional calculations show that water molecules are a critical factor for stabilizing the structure of the interfacial layer. The interfacial layer stabilizes a crystal-like structure compatible with liquid-like ion and solvent mobilities. At saturation, some ions precipitate and small crystals are formed on the mica. PMID:27416784
Lekakis, Garyfalia; Claes, Peter; Hamilton, Grant S; Hellings, P W
2016-02-01
During the preoperative assessment in rhinoplasty, the surgeon takes a thorough history, performs a complete examination by assessing functional and aesthetic aspects of the nose, obtains a clear understanding of the patient's wishes, conducts facial analysis based on standardized photography, and communicates to the patient the goals and pitfalls of surgery. Computer imaging or morphing of the preoperative pictures of the nose has drawn a lot of interest in the last decade, and it is a sign of evolution of the preoperative consultation. Technological advances, also in the context of rhinoplasty, have led to the development of three-dimensional (3D) imaging techniques, and have completely revolutionized the way that surgeons manage their patients preoperatively and evaluate postoperative results today. The accurate 3D surface imaging aids the surgeon to communicate with the patient adequately before surgery, to set an appropriate surgical plan, and to measure the shape and volume changes of the patient's nose that result from the intervention. The present review provides an analysis on the current knowledge of 3D surface imaging in rhinoplasty derived from the literature, and highlights future directions of preoperative and postoperative assessment in the field. PMID:26862969
Martin-Jimenez, Daniel; Chacon, Enrique; Tarazona, Pedro; Garcia, Ricardo
2016-01-01
Interfacial liquid layers play a central role in a variety of phenomena ranging from friction to molecular recognition. Liquids near a solid surface form an interfacial layer where the molecular structure is different from that of the bulk. Here we report atomic resolution three-dimensional images of electrolyte solutions near a mica surface that demonstrate the existence of three types of interfacial structures. At low concentrations (0.01-1 M), cations are adsorbed onto the mica. The cation layer is topped by a few hydration layers. At higher concentrations, the interfacial layer extends several nanometres into the liquid. It involves the alternation of cation and anion planes. Fluid Density Functional calculations show that water molecules are a critical factor for stabilizing the structure of the interfacial layer. The interfacial layer stabilizes a crystal-like structure compatible with liquid-like ion and solvent mobilities. At saturation, some ions precipitate and small crystals are formed on the mica. PMID:27416784
Development of a three-dimensional surface imaging system for melanocytic skin lesion evaluation
NASA Astrophysics Data System (ADS)
Tosca, Androniki; Kokolakis, Athanasios; Lasithiotakis, Konstantinos; Zacharopoulos, Athanasios; Zabulis, Xenophon; Marnelakis, Ioannis; Ripoll, Jorge; Stephanidis, Constantine
2013-01-01
Even though surface morphology is always taken into account when assessing clinically pigmented skin lesions, it is not captured by most modern imaging systems using digital imaging. Our aim is to develop a novel three-dimensional (3D) imaging technique to record detailed information of the surface anatomy of melanocytic lesions that will enable improved classification through digital imaging. The apparatus consists of three high-resolution cameras, a light source, and accompanying software. Volume measurements of specific phantoms using volumetric tubes render slightly lower values than those obtained by our 3D imaging system (mean%±SD, 3.8%±0.98, P<0.05). To examine the reproducibility of the method, sequential imaging of melanocytic lesions is carried out. The mean%±SD differences of area, major axis length, volume, and maximum height are 2.1%±1.1, 0.9%±0.8, 3.8%±2.9, and 2.5%±3.5, respectively. Thirty melanocytic lesions are assessed, including common and dysplastic nevi and melanomas. There is a significant difference between nevi and melanomas in terms of variance in height and boundary asymmetry (P<0.001). Moreover, dysplastic nevi have significantly higher variances in pigment density values than common nevi (P<0.001). Preliminary data suggest that our instrument has great potential in the evaluation of the melanocytic lesions. However, these findings should be confirmed in larger-scale studies.
NASA Astrophysics Data System (ADS)
Li, Dong; Tian, Jindong
2010-11-01
An embedded three-dimensional (3-D) profilometry system based on a combination of gray-code and phase shifting (GCPS) method is proposed. This system consists of a digital-micromirror-device (DMD) based video projector, a high-speed CCD camera and an embedded digital signal processing hardware system based on DSP. In this technique, seven gray-code patterns and three sinusoidal fringe patterns with 120-deg phase shift are integrated in red, green and blue channels to form four color fringe patterns. When the four color fringe patterns are sent to the DMD based projector without color filter, the previous gray-code patterns and three sinusoidal fringe patterns are repeatedly projected to an object surface in gray-scale sequentially. These fringe patterns deformed by the object surface are captured by a high-speed CCD camera synchronized with the projector. An embedded hardware system is developed for synchronization between the camera and the projector and taking full advantage of DSP parallel processing capability for real-time phase retrieve and 3-D reconstruction. Since the number of projected images of GCPS is reduced from 11 to 4, the measurement speed is enhanced dramatically. Experimental results demonstrated the feasibility of the proposed technique for high-speed 3-D shape measurement.
Reconciling surface plate motions with rapid three-dimensional mantle flow around a slab edge.
Jadamec, Margarete A; Billen, Magali I
2010-05-20
The direction of tectonic plate motion at the Earth's surface and the flow field of the mantle inferred from seismic anisotropy are well correlated globally, suggesting large-scale coupling between the mantle and the surface plates. The fit is typically poor at subduction zones, however, where regional observations of seismic anisotropy suggest that the direction of mantle flow is not parallel to and may be several times faster than plate motions. Here we present three-dimensional numerical models of buoyancy-driven deformation with realistic slab geometry for the Alaska subduction-transform system and use them to determine the origin of this regional decoupling of flow. We find that near a subduction zone edge, mantle flow velocities can have magnitudes of more than ten times the surface plate motions, whereas surface plate velocities are consistent with plate motions and the complex mantle flow field is consistent with observations from seismic anisotropy. The seismic anisotropy observations constrain the shape of the eastern slab edge and require non-Newtonian mantle rheology. The incorporation of the non-Newtonian viscosity results in mantle viscosities of 10(17) to 10(18) Pa s in regions of high strain rate (10(-12) s(-1)), and this low viscosity enables the mantle flow field to decouple partially from the motion of the surface plates. These results imply local rapid transport of geochemical signatures through subduction zones and that the internal deformation of slabs decreases the slab-pull force available to drive subducting plates. PMID:20485433
A combined direct/inverse three-dimensional transonic wing design method for vector computers
NASA Technical Reports Server (NTRS)
Weed, R. A.; Carlson, L. A.; Anderson, W. K.
1984-01-01
A three-dimensional transonic-wing design algorithm for vector computers is developed, and the results of sample computations are presented graphically. The method incorporates the direct/inverse scheme of Carlson (1975), a Cartesian grid system with boundary conditions applied at a mean plane, and a potential-flow solver based on the conservative form of the full potential equation and using the ZEBRA II vectorizable solution algorithm of South et al. (1980). The accuracy and consistency of the method with regard to direct and inverse analysis and trailing-edge closure are verified in the test computations.
Three-dimensional shape variation of talar surface morphology in hominoid primates.
Parr, W C H; Soligo, C; Smaers, J; Chatterjee, H J; Ruto, A; Cornish, L; Wroe, S
2014-07-01
The hominoid foot is of particular interest to biological anthropologists, as changes in its anatomy through time reflect the adoption of terrestrial locomotion, particularly in species of Australopithecus and Homo. Understanding the osteological morphology associated with changes in whole foot function and the development of the plantar medial longitudinal foot arch are key to understanding the transition through habitual bipedalism in australopithecines to obligate bipedalism and long-distance running in Homo. The talus is ideal for studying relationships between morphology and function in this context, as it is a major contributor to the adduction-abduction, plantar-dorsal flexion and inversion-eversion of the foot, and transmits all forces encountered from the foot to the leg. The talar surface is predominantly covered by articular facets, which have different quantifiable morphological characters, including surface area, surface curvature and orientation. The talus also presents challenges to the investigator, as its globular shape is very difficult to quantify accurately and reproducibly. Here we apply a three-dimensional approach using type 3 landmarks (slid semilandmarks) that are geometrically homologous to determine overall talar shape variations in a range of living and fossil hominoid taxa. Additionally, we use novel approaches to quantify the relative orientations and curvatures of talar articular facets by determining the principal vectors of facet orientation and fitting spheres to articular facets. The resulting metrics are analysed using phylogenetic regressions and principal components analyses. Our results suggest that articular surface curvatures reflect locomotor specialisations with, in particular, orangutans having more highly curved facets in all but the calcaneal facet. Similarly, our approach to quantifying articular facet orientation appears to be effective in discriminating between extant hominoid species, and may therefore provide a
Krbecek, R; Gebhardt, C; Gruler, H; Sackmann, E
1979-06-13
A method of three-dimensional reconstruction of the surface profile of artificial and natural membranes from freeze quenched electron micrographs is presented. The method is based on the analysis of the variation in thickness of platinum layers, deposited under an oblique angle. In essence, it is reminiscent of the method of Eratosthenes to measure the earth's radius. The thickness of etch-like protrusions of membranes could be determined to an accuracy of about 3 A. True distances on curved surfaces rather than projections of distances are obtained. The method has been applied to both model membranes and biological membranes. The essential results are: 1. Detailed information on the symmetry and the molecular structure of the crystalline phases of dimyristoyl phosphatidylcholine was obtained. The microscopic surface profile of the ripple structure observed between the pretransition and the main transition was analysed. In accordance with a previous model we found that the ripple structure is caused by the spontaneous curvature of the monolayers. The surface profiles of the ripple structure and of the low temperature biaxial phase could be clearly distinguished. 2. The sizes and shapes of lipid domains formed by both thermically and charge-induced lateral phase separation were determined. This showed that the visual inspection of electron micrographs may lead to a considerable underestimation of the domain size. Conclusions may be drawn concerning the different phases formed upon lateral phase separation. 3. As a biological example, yeast cell membranes were studied. The method allows one to distinguish between different membrane-bound proteins by measuring the width-to-height ratio of the particles. The deformation of the lipid layer in the environment of the proteins may be determined. This deformation contains information about lipid-mediated long-range interactions between membrane proteins. PMID:378255
Three-dimensional shape variation of talar surface morphology in hominoid primates
Parr, W C H; Soligo, C; Smaers, J; Chatterjee, H J; Ruto, A; Cornish, L; Wroe, S
2014-01-01
The hominoid foot is of particular interest to biological anthropologists, as changes in its anatomy through time reflect the adoption of terrestrial locomotion, particularly in species of Australopithecus and Homo. Understanding the osteological morphology associated with changes in whole foot function and the development of the plantar medial longitudinal foot arch are key to understanding the transition through habitual bipedalism in australopithecines to obligate bipedalism and long-distance running in Homo. The talus is ideal for studying relationships between morphology and function in this context, as it is a major contributor to the adduction–abduction, plantar–dorsal flexion and inversion–eversion of the foot, and transmits all forces encountered from the foot to the leg. The talar surface is predominantly covered by articular facets, which have different quantifiable morphological characters, including surface area, surface curvature and orientation. The talus also presents challenges to the investigator, as its globular shape is very difficult to quantify accurately and reproducibly. Here we apply a three-dimensional approach using type 3 landmarks (slid semilandmarks) that are geometrically homologous to determine overall talar shape variations in a range of living and fossil hominoid taxa. Additionally, we use novel approaches to quantify the relative orientations and curvatures of talar articular facets by determining the principal vectors of facet orientation and fitting spheres to articular facets. The resulting metrics are analysed using phylogenetic regressions and principal components analyses. Our results suggest that articular surface curvatures reflect locomotor specialisations with, in particular, orang-utans having more highly curved facets in all but the calcaneal facet. Similarly, our approach to quantifying articular facet orientation appears to be effective in discriminating between extant hominoid species, and may therefore
Three-dimensional structure of the wind-driven water surface flow
NASA Astrophysics Data System (ADS)
Caulliez, Guillemette
2014-05-01
The structure of the water boundary layer forced by wind underneath surface wind waves is investigated experimentally in the large Marseille-Luminy wind wave tank. Measurements of the vertical velocity profiles inside the subsurface shear layer were performed by a three-component Nortek acoustic Doppler velocimeter. An overview of the water surface flow patterns which develop at larger scales was provided by simultaneous flow visualizations. To that end, tiny hydrogen bubbles were generated by electrolysis along a 60 cm long thin wire set up crosswise to the wind direction at a short distance from the water surface. The bubble motions were recorded by a video camera looking vertically from below or above the water surface. Observations were made at low to moderate wind speeds for four fetches ranging from 2 to 26 m. This work reveals that under such steady wind conditions, the transition of the water surface boundary layer to turbulent flow is marked by the fast development of coherent longitudinal vortices downstream the surface wave generation area observed at short fetches. These structures are characterized by the occurrence of intense upwellings localized in narrow streaks in the crosswise direction. There, the upper wind-induced shear flow is confined in a very thin layer. In the wider areas between these streaks, the surface flow exhibits a much more turbulent behaviour over a deeper but slightly-sheared boundary layer. In accordance with this inhomogeneous flow pattern, the velocity field observed at a fixed location over one vertical profile is highly variable in time. These three-dimensional large-scale structures present strong similarities with the so-called Langmuir circulations. This work will focus on the description of the qualitative and quantitative properties of these longitudinal vortices, in particular the conditions of their occurence and the dependency of their characteristic scales on wind forcing and surface wave development. The main
Cytopede: A Three-Dimensional Tool for Modeling Cell Motility on a Flat Surface
Dembo, Micah
2010-01-01
Abstract When cultured on flat surfaces, fibroblasts and many other cells spread to form thin lamellar sheets. Motion then occurs by extension of the sheet at the leading edge and retraction at the trailing edge. Comprehensive quantitative models of these phenomena have so far been lacking and to address this need, we have designed a three-dimensional code called Cytopede specialized for the simulation of the mechanical and signaling behavior of plated cells. Under assumptions by which the cytosol and the cytoskeleton are treated from a continuum mechanical perspective, Cytopede uses the finite element method to solve mass and momentum equations for each phase, and thus determine the time evolution of cellular models. We present the physical concepts that underlie Cytopede together with the algorithms used for their implementation. We then validate the approach by a computation of the spread of a viscous sessile droplet. Finally, to exemplify how Cytopede enables the testing of ideas about cell mechanics, we simulate a simple fibroblast model. We show how Cytopede allows computation, not only of basic characteristics of shape and velocity, but also of maps of cell thickness, cytoskeletal density, cytoskeletal flow, and substratum tractions that are readily compared with experimental data. PMID:20958108
DNA-guided assembly of three-dimensional nanostructures for surface-enhanced Raman spectroscopy
NASA Astrophysics Data System (ADS)
Wu, Li-An; Lin, Yu-Ting; Chen, Yih-Fan
2015-03-01
Surface enhancement Raman spectroscopy (SERS) has drawn much attention in recent years because its ability to greatly enhance Raman signals to allow for the detection of molecules at low concentration. When using metallic nanoparticles as SERS substrates, many studies have shown that the size of the interparticle gap significantly affects the enhancement of the Raman signals. Given that the optimal interparticle gap is as small as a few nanometers, fabricating sensitive, uniform, and reproducible SERS substrates remains challenging. Here we report a three-dimensional SERS substrate created through the assembly of core-shell nanoparticles using DNA. By using DNA of appropriate sequence and length, DNA-functionalized nanoparticles were assembled into ordered and highly packed nanostructures. The interparticle distance was precisely controlled by adjusting the design of the DNA and the thickness of the silver shell coated on the gold nanoparticles. Compared with randomly aggregated nanoparticles, the interparticle distance in the synthesized nanostructures can be more uniform and better controlled. In addition, the DNA-guided assembly process allows us to create precise nanostructures without using complex and expensive fabrication methods. The study demonstrates that the synthesized nanostructures can be used as effective SERS substrates to successfully measure the Raman signals of malachite green, a toxic compound that is sometimes illegally used on fish, as well as Fluorescein isothiocyanate (FITC) at low concentrations.
Rajon, D A; Patton, P W; Shah, A P; Watchman, C J; Bolch, W E
2002-05-01
The most recent methods for trabecular bone dosimetry are based on Monte Carlo transport simulations within three-dimensional (3D) images of real human bone samples. Nuclear magnetic resonance and micro-computed tomography have been commonly used as imaging tools for studying trabecular microstructure. In order to evaluate the accuracy of these techniques for radiation dosimetry, a previous study was conducted that showed an overestimate in the absorbed fraction of energy for low-energy electrons emitted within the marrow space and irradiating the bone trabeculae. This problem was found to be related to an overestimate of the surface area of the true bone-marrow interface within the 3D digital images, and was identified as the surface-area effect. The goal of the present study is to better understand how this surface-area effect occurs in the case of single spheres representing individual marrow cavities within trabecular bone. First, a theoretical study was conducted which showed that voxelization of the spherical marrow cavity results in a 50% overestimation of the spherical surface area. Moreover, this overestimation cannot be reduced through a reduction in the voxel size (e.g., improved image resolution). Second, a series of single-sphere marrow cavity models was created with electron sources simulated within the sphere (marrow source) and outside the sphere (bone trabeculae source). The series of single-sphere models was then voxelized to represent 3D digital images of varying resolution. Transport calculations were made for both marrow and bone electron sources within these simulated images. The study showed that for low-energy electrons (<100 keV), the 50% overestimate of the bone-marrow interface surface area can lead to a 50% overestimate of the cross-absorbed fraction. It is concluded that while improved resolution will not reduce the surface area effects found within 3D image-based transport models, a tenfold improvement in current image resolution would
Yoon, Hyeon; Kim, Geunhyung
2011-02-01
A new three-dimensional (3D) scaffold containing a functional drug delivery system (DDS) consisting of electrospun micro/nanofibers is proposed. In the DDS scaffold, a core-shell laminated, structured, electrospun mat of hydrophobic polycaprolactone (PCL) and hydrophilic poly(ethylene oxide) (PEO)/rhodamine-B fibers was embedded in the normal 3D PCL scaffold, which was fabricated by a melt-plotting system. Rhodamine release from the scaffold was controlled physically by the thickness change of the PCL layer, and initial burst in drug release was eliminated by an appropriate thickness of the PCL layer. This simple technique may be useful in fabricating DDS-functional scaffolds for the clinical areas not only of bone and skin regeneration, but also of other tissue regeneration areas, regardless of the degradation rate of the structural scaffold. PMID:20740676
Markovic, Marica; Van Hoorick, Jasper; Hölzl, Katja; Tromayer, Maximilian; Gruber, Peter; Nürnberger, Sylvia; Dubruel, Peter; Van Vlierberghe, Sandra; Liska, Robert; Ovsianikov, Aleksandr
2015-01-01
Three-dimensional (3D) printing offers versatile possibilities for adapting the structural parameters of tissue engineering scaffolds. However, it is also essential to develop procedures allowing efficient cell seeding independent of scaffold geometry and pore size. The aim of this study was to establish a method for seeding the scaffolds using photopolymerizable cell-laden hydrogels. The latter facilitates convenient preparation, and handling of cell suspension, while distributing the hydrogel precursor throughout the pores, before it is cross-linked with light. In addition, encapsulation of living cells within hydrogels can produce constructs with high initial cell loading and intimate cell-matrix contact, similar to that of the natural extra-cellular matrix (ECM). Three dimensional scaffolds were produced from poly(lactic) acid (PLA) by means of fused deposition modeling. A solution of methacrylamide-modified gelatin (Gel-MOD) in cell culture medium containing photoinitiator Li-TPO-L was used as a hydrogel precursor. Being an enzymatically degradable derivative of natural collagen, gelatin-based matrices are biomimetic and potentially support the process of cell-induced remodeling. Preosteoblast cells MC3T3-E1 at a density of 10 × 106 cells per 1 mL were used for testing the seeding procedure and cell proliferation studies. Obtained results indicate that produced constructs support cell survival and proliferation over extended duration of our experiment. The established two-step approach for scaffold seeding with the cells is simple, rapid, and is shown to be highly reproducible. Furthermore, it enables precise control of the initial cell density, while yielding their uniform distribution throughout the scaffold. Such hybrid tissue engineering constructs merge the advantages of rigid 3D printed constructs with the soft hydrogel matrix, potentially mimicking the process of ECM remodeling. PMID:26858826
Surface-to-surface scattering in three-dimensional (3D) topological insulator (TI) thin films
NASA Astrophysics Data System (ADS)
Yin, Gen; Wickramaratne, Darshana; Lake, Roger
2013-03-01
When the thickness of a 3D TI material is reduced below approximately 6nm, hybridization of the opposite surfaces states can result in inter-surface tunneling. Due to the rotational symmetry of the thin film, the k-s locking relation on opposite surfaces also has opposite chirality. Thus, in this inter-surface scattering mechanism, back-scattering is allowed without the flip of the spin. This effect breaks the protection of TI surface states against back-scattering. To investigate the influence of the inter-surface scattering mechanism, we study different near-elastic scattering mechanisms in the surface state transport using Boltzmann transport equations within the relaxation time approximation. The effect of screened Coulomb impurities, low-energy acoustic phonons and surface magnetic impurities on the TI surface states will be discussed. The response of the inter-surface scattering of TI states to various external stimuli such as a Rashba-like splitting and the orientation of the impurity magnetic moments will also be presented. Using our simulation results, we propose possible experimental methods to modulate the back-scatter protection of TI surface states in thin film TI materials.
Human body surface area: measurement and prediction using three dimensional body scans.
Tikuisis, P; Meunier, P; Jubenville, C E
2001-08-01
The development of three dimensional laser scanning technology and sophisticated graphics editing software have allowed an alternative and potentially more accurate determination of body surface area (BSA). Raw whole-body scans of 641 adults (395 men and 246 women) were obtained from the anthropometric data base of the Civilian American and European Surface Anthropometry Resource project. Following surface restoration of the scans (i.e. patching and smoothing), BSA was calculated. A representative subset of the entire sample population involving 12 men and 12 women (G24) was selected for detailed measurements of hand surface area (SAhand) and ratios of surface area to volume (SA/VOL) of various body segments. Regression equations involving wrist circumference and arm length were used to predict SAhand of the remaining population. The overall [mean (SD)] of BSA were 2.03 (0.19) and 1.73 (0.19) m2 for men and women, respectively. Various prediction equations were tested and although most predicted the measured BSA reasonably closely, residual analysis revealed an overprediction with increasing body size in most cases. Separate non-linear regressions for each sex yielded the following best-fit equations (with root mean square errors of about 1.3%): BSA (cm2) = 128.1 x m0.44 x h0.60 for men and BSA = 147.4 x m0.47 x h0.55 for women, where m, body mass, is in kilograms and h, height, is in centimetres. The SA/VOL ratios of the various body segments were higher for the women compared to the men of G24, significantly for the head plus neck (by 7%), torso (19%), upper arms (15%), forearms (20%), hands (18%), and feet (11%). The SA/VOL for both sexes ranged from approximately 12.m-1 for the pelvic region to 104-123.m-1 for the hands, and shape differences were a factor for the torso and lower leg. PMID:11560080
NASA Astrophysics Data System (ADS)
Wang, Zhigang; Fu, Yanjun; Yang, Jie; Xia, Guisuo; Wang, Jiasheng
2013-10-01
Blade is the key component of the aero-engine. In generally, it requires precise size and accurate shape, so the three-dimensional shape measurement of the blade is very important. Fringe projection profilometry is generally used to measure the 3D shape of an object, because of the advantages of non-contact operation, full-field acquisition, high resolution, and fast data processing. In this paper, 3D shape measurement method based on surface structured light that combination of gray-code and phase-shift projection is proposed. The wrapped phase of the blade is got by the four-step phase-shift method. In the projection process of the gray-code, due to the ambient light, different surface reflectance and surface physical discontinuous, the edge of gray-code becomes smooth, leading to decode error, so that the gray-code pattern must be binaried before decode. Through the accurate binarization of the blade gray-code pattern, the decoding cycle of the blade is achieved, and the unwrapped phase is achieved by phase unwrapping. Then the unwrapped phase difference between the blade and reference plane is got, the height of the blade can be obtained by the relationship between the phase difference and the height. The experimental and simulation results show that the proposed method can achieve a high precision, high speed and low cost 3D shape measurement of the blade. The measurement accuracy reaches 0.03 mm. The proposed method extends the reliability and practicality of the fringe projection profilometry.
Three Dimensional Dirac Semimetals
NASA Astrophysics Data System (ADS)
Zaheer, Saad
2014-03-01
Dirac points on the Fermi surface of two dimensional graphene are responsible for its unique electronic behavior. One can ask whether any three dimensional materials support similar pseudorelativistic physics in their bulk electronic spectra. This possibility has been investigated theoretically and is now supported by two successful experimental demonstrations reported during the last year. In this talk, I will summarize the various ways in which Dirac semimetals can be realized in three dimensions with primary focus on a specific theory developed on the basis of representations of crystal spacegroups. A three dimensional Dirac (Weyl) semimetal can appear in the presence (absence) of inversion symmetry by tuning parameters to the phase boundary separating a bulk insulating and a topological insulating phase. More generally, we find that specific rules governing crystal symmetry representations of electrons with spin lead to robust Dirac points at high symmetry points in the Brillouin zone. Combining these rules with microscopic considerations identifies six candidate Dirac semimetals. Another method towards engineering Dirac semimetals involves combining crystal symmetry and band inversion. Several candidate materials have been proposed utilizing this mechanism and one of the candidates has been successfully demonstrated as a Dirac semimetal in two independent experiments. Work carried out in collaboration with: Julia A. Steinberg, Steve M. Young, J.C.Y. Teo, C.L. Kane, E.J. Mele and Andrew M. Rappe.
A binocular machine vision system for three-dimensional surface measurement of small objects.
Gorpas, Dimitris; Politopoulos, Kostas; Yova, Dido
2007-12-01
Rendering three-dimensional information of a scene from optical measurements is very important for a wide variety of applications. However, computer vision advancements have not yet achieved the accurate three-dimensional reconstruction of objects smaller than 1 cm diameter. This paper describes the development of a novel volumetric method for small objects, using a binocular machine vision system. The achieved precision is high, providing a standard deviation of 0.04 mm. The robustness, of the system, issues from the lab prototype imaging system with the crucial z-axis movement without the need of further calibration and the fully automated volumetric algorithms. PMID:17881188
A quasi-three-dimensional blade surface boundary layer analysis for rotating blade rows
NASA Technical Reports Server (NTRS)
Thompkins, W. T., Jr.; Usab, W. J., Jr.
1981-01-01
A quasi-three-dimensional approximation has been developed for a blade boundary layer which involves the calculation of the effect of nonzero pressure gradients, turbulent flow, and blade twist, but includes only a simple coupling between streamlines. The resulting set of equations is solved using Keller's box scheme. The solution scheme is checked against available incompressible flow solutions and then applied to a NASA low aspect ratio transonic compressor stage for which extensive experimental and computational data are available. It is found that the three-dimensional boundary layer separates significantly sooner and has a much larger influence on rotor performance than would be expected from a two-dimensional analysis.
Three-dimensional numerical simulation of near-surface flows over the Martian north polar CAP
NASA Astrophysics Data System (ADS)
Parish, Thomas R.; Howard, A. D.
Measurements made by Viking Lander VL-2 (48 N) have shown that the near-surface wind and temperature regime on Mars displays striking similarities to terrestrial counterparts. The diurnal radiative cycle is responsible for establishment of a well-defined thermal circulation in which downslope (Katabatic) flows prevail during the nighttime hours and weak upslope (anabatic) conditions prevail during the daytime. Previous work has indicated that the slope flows are much like those found on Earth, particularly the Katabatic winds, which show striking similarities to drainage flows observed over Antarctica. The low-level wind regime appears to be an important factor in the scouring of the martian landscape. The north polar cap shows evidence of eolian features such as dunes, frost streaks, and grooves from Viking imagery. The direction of the prevailing wind can in cases be inferred from the eolian features. We examine the thermally induced flows that result from the radiative heating and cooling of the martian north polar region using a comprehensive three-dimensional atmospheric mesoscale numerical model. The same model has been used previously for simulation of Antarctic Katabatic winds. The model equations are written in terrain-following coordinates to allow for irregular terrain; prognostic equations include the flux forms of the horizontal momentum equations, temperature, continuity. A surface energy budget equation is also incorporated in which the surface temperature is determined. Explicit parameterization of both terrestrial (longwave) and solar (shortwave) radiation is included. Turbulent transfer of heat and momentum in the martian atmosphere is assumed to follow the similarity expressions in the surface boundary layer on Earth. The terrain heights for the martian north polar region have been obtained from the U.S. Geological Survey map and digitized onto a 57x57 grid with a spacing of 75 km. The resulting terrain map is shown in Fig. 1. The vertical grid
Three-dimensional numerical simulation of near-surface flows over the Martian north polar cap
NASA Technical Reports Server (NTRS)
Parish, Thomas R.; Howard, A. D.
1993-01-01
Measurements made by Viking Lander VL-2 (48 N) have shown that the near-surface wind and temperature regime on Mars displays striking similarities to terrestrial counterparts. The diurnal radiative cycle is responsible for establishment of a well-defined thermal circulation in which downslope (Katabatic) flows prevail during the nighttime hours and weak upslope (anabatic) conditions prevail during the daytime. Previous work has indicated that the slope flows are much like those found on Earth, particularly the Katabatic winds, which show striking similarities to drainage flows observed over Antarctica. The low-level wind regime appears to be an important factor in the scouring of the martian landscape. The north polar cap shows evidence of eolian features such as dunes, frost streaks, and grooves from Viking imagery. The direction of the prevailing wind can in cases be inferred from the eolian features. We examine the thermally induced flows that result from the radiative heating and cooling of the martian north polar region using a comprehensive three-dimensional atmospheric mesoscale numerical model. The same model has been used previously for simulation of Antarctic Katabatic winds. The model equations are written in terrain-following coordinates to allow for irregular terrain; prognostic equations include the flux forms of the horizontal momentum equations, temperature, continuity. A surface energy budget equation is also incorporated in which the surface temperature is determined. Explicit parameterization of both terrestrial (longwave) and solar (shortwave) radiation is included. Turbulent transfer of heat and momentum in the martian atmosphere is assumed to follow the similarity expressions in the surface boundary layer on Earth. The terrain heights for the martian north polar region have been obtained from the U.S. Geological Survey map and digitized onto a 57x57 grid with a spacing of 75 km. The resulting terrain map is shown in Fig. 1. The vertical grid
NASA Astrophysics Data System (ADS)
Najeeb, Umair
This thesis experimentally investigates the enhancement of single-phase heat transfer, frictional loss and pressure drop characteristics in a Single Heater Element Loop Tester (SHELT). The heater element simulates a single fuel rod for Pressurized Nuclear reactor. In this experimental investigation, the effect of the outer surface roughness of a simulated nuclear rod bundle was studied. The outer surface of a simulated fuel rod was created with a three-dimensional (Diamond-shaped blocks) surface roughness. The angle of corrugation for each diamond was 45 degrees. The length of each side of a diamond block is 1 mm. The depth of each diamond block was 0.3 mm. The pitch of the pattern was 1.614 mm. The simulated fuel rod had an outside diameter of 9.5 mm and wall thickness of 1.5 mm and was placed in a test-section made of 38.1 mm inner diameter, wall thickness 6.35 mm aluminum pipe. The Simulated fuel rod was made of Nickel 200 and Inconel 625 materials. The fuel rod was connected to 10 KW DC power supply. The Inconel 625 material of the rod with an electrical resistance of 32.3 kO was used to generate heat inside the test-section. The heat energy dissipated from the Inconel tube due to the flow of electrical current flows into the working fluid across the rod at constant heat flux conditions. The DI water was employed as working fluid for this experimental investigation. The temperature and pressure readings for both smooth and rough regions of the fuel rod were recorded and compared later to find enhancement in heat transfer coefficient and increment in the pressure drops. Tests were conducted for Reynold's Numbers ranging from 10e4 to 10e5. Enhancement in heat transfer coefficient at all Re was recorded. The maximum heat transfer co-efficient enhancement recorded was 86% at Re = 4.18e5. It was also observed that the pressure drop and friction factor increased by 14.7% due to the increased surface roughness.
Chemical functionalization of surfaces for building three-dimensional engineered biosensors
NASA Astrophysics Data System (ADS)
Marques, Marco E.; Mansur, Alexandra A. P.; Mansur, Herman S.
2013-06-01
This study presents a new approach for developing biosensors based on enzymatic systems with designed three-dimensional structures. Silica glass slides were chemically functionalized at surfaces by reacting with organosilanes, 3-mercaptopropyltriethoxysilane (MPTES), and 3-aminopropyltriethoxysilane (APTES), using sol-gel process at room temperature. The functionalization of the supports was characterized by contact angle measurements and FTIR spectroscopy. The first enzyme layer was covalently immobilized to the support by a bi-functional linker (glutaraldehyde). The second enzyme layer was deposited using the protein conjugation method based on the high affinity "avidin-biotin" interactions. Each enzyme was biotinylated before being added to the nanostructured system and avidin was used as the binder between consecutive enzyme layers. The biochemical response was assayed at all stages to certify that the enzymatic bioactivity was retained throughout the entire layer-by-layer (LBL) process. The model of building 3D-enzymatic systems was evaluated using the enzymatic structure with glucose oxidase (GOx) and horseradish peroxidase (HRP). It was verified that the amino-modified support presented the highest bioactivity response compared to the other chemical functionalities. Moreover, the bienzyme nanostructure demonstrated relevant biochemical activity upon injecting the glucose substrate into the system. Finally, as a proof of concept, the bienzyme systems were assayed using real samples of regular and sugar-free soft drinks where they effectively behaved as structured biosensor for glucose with the built-in 3D hybrid architecture. Based on the results, it can be foreseen the development of promising new nanomaterials for several analytical applications such as monitoring the quality of food and beverages for nutrition purposes.
NASA Astrophysics Data System (ADS)
Nakagawa, Takashi; Kim, Jaeho; Toba, Takayuki; Katsurai, Makoto
A three dimensional simulation code with the finite difference time domain (FDTD) method combined with the fluid model for electron has been developed for the microwave excited surface wave plasma in the RDL-SWP device. This code permits the numerical analysis of the spatial distributions of electric field, power absorption, electron density and electron temperature. At low gas pressure of about 10 mTorr, the numerical results were compared with the experimental measurements that show the validity of this 3-D simulation code. A simplified analysis assuming that an electron density is spatially uniform has been studied and its applicability is evaluated by the 3-D simulation. The surface wave eigenmodes are determined by the electron density, and it is found that the structure of the device strongly influences to the spatial distribution of the electric fields of surface waves in a low density area (ne<3.0×1011cm-3). A method to irradiate a microwave to the whole surface area of the plasma is proposed which is found to be effective to obtain a high uniformity distribution of electron density.
NASA Astrophysics Data System (ADS)
So, Hongyun; Senesky, Debbie G.
2016-01-01
In this letter, three-dimensional gateless AlGaN/GaN high electron mobility transistors (HEMTs) were demonstrated with 54% reduction in electrical resistance and 73% increase in surface area compared with conventional gateless HEMTs on planar substrates. Inverted pyramidal AlGaN/GaN surfaces were microfabricated using potassium hydroxide etched silicon with exposed (111) surfaces and metal-organic chemical vapor deposition of coherent AlGaN/GaN thin films. In addition, electrical characterization of the devices showed that a combination of series and parallel connections of the highly conductive two-dimensional electron gas along the pyramidal geometry resulted in a significant reduction in electrical resistance at both room and high temperatures (up to 300 °C). This three-dimensional HEMT architecture can be leveraged to realize low-power and reliable power electronics, as well as harsh environment sensors with increased surface area.
Berlincourt, Maud; Angel, Lauren P; Arnould, John P Y
2015-01-01
Determining the foraging behaviour of free-ranging marine animals is fundamental for assessing their habitat use and how they may respond to changes in the environment. However, despite recent advances in bio-logging technology, collecting information on both at-sea movement patterns and activity budgets still remains difficult in small pelagic seabird species due to the constraints of instrument size. The short-tailed shearwater, the most abundant seabird species in Australia (ca 23 million individuals), is a highly pelagic procellariiform. Despite its ecological importance to the region, almost nothing is known about its at-sea behaviour, in particular, its foraging activity. Using a combination of GPS and tri-axial accelerometer data-loggers, the fine scale three-dimensional foraging behaviour of 10 breeding individuals from two colonies was investigated. Five at-sea behaviours were identified: (1) resting on water, (2) flapping flight, (3) gliding flight, (4) foraging (i.e., surface foraging and diving events), and (5) taking-off. There were substantial intra- and inter- individual variations in activity patterns, with individuals spending on average 45.8% (range: 17.1-70.0%) of time at sea resting on water and 18.2% (range: 2.3-49.6%) foraging. Individuals made 76.4 ± 65.3 dives (range: 8-237) per foraging trip (mean duration 9.0 ± 1.9 s), with dives also recorded during night-time. With the continued miniaturisation of recording devices, the use of combined data-loggers could provide us with further insights into the foraging behaviour of small procellariiforms, helping to better understand interactions with their prey. PMID:26439491
Kaspersen, J.H. Sjolie, E.; Wesche, J.; Asland, J.; Lundbom, J.; Odegard, A.; Lindseth, F.; Nagelhus Hernes, T.A.
2003-08-15
Purpose: Three-dimensional (3D)intraoperative ultrasound may be easier to interpret when used in combination with less noisy preoperative image data such as CT. The purpose of this study was to evaluate the use of preoperative image data in a 3D ultrasound-based navigation system specially designed for minimally invasive abdominal surgery. A prototype system has been tested in patients with aortic aneurysms undergoing clinical assessment before and after abdominal aortic stent-graft implantation. Methods: All patients were first imaged by spiral CT followed by 3D ultrasound scanning. The CT volume was registered to the patient using fiducial markers. This enabled us to compare corresponding slices from 3D ultrasound and CT volumes. The accuracy of the patient registration was evaluated both using the external fiducial markers (artificial landmarks glued on the patient's skin) and using intraoperative 3D ultrasound as a measure of the true positioning of anatomic landmarks inside the body. Results: The mean registration accuracy on the surface was found to be 7.1 mm, but increased to 13.0 mm for specific landmarks inside the body. CT and ultrasound gave supplementary information of surrounding structures and position of the patient's anatomy. Fine-tuning the initial patient registration of the CT data with a multimodal CT to intraoperative 3D ultrasound registration (e.g., mutual information), as well as ensuring no movements between this registration and image guidance, may improve the registration accuracy. Conclusion: Preoperative CT in combination with 3D ultrasound might be helpful for guiding minimal invasive abdominal interventions.
Berlincourt, Maud; Angel, Lauren P.; Arnould, John P. Y.
2015-01-01
Determining the foraging behaviour of free-ranging marine animals is fundamental for assessing their habitat use and how they may respond to changes in the environment. However, despite recent advances in bio-logging technology, collecting information on both at-sea movement patterns and activity budgets still remains difficult in small pelagic seabird species due to the constraints of instrument size. The short-tailed shearwater, the most abundant seabird species in Australia (ca 23 million individuals), is a highly pelagic procellariiform. Despite its ecological importance to the region, almost nothing is known about its at-sea behaviour, in particular, its foraging activity. Using a combination of GPS and tri-axial accelerometer data-loggers, the fine scale three-dimensional foraging behaviour of 10 breeding individuals from two colonies was investigated. Five at-sea behaviours were identified: (1) resting on water, (2) flapping flight, (3) gliding flight, (4) foraging (i.e., surface foraging and diving events), and (5) taking-off. There were substantial intra- and inter- individual variations in activity patterns, with individuals spending on average 45.8% (range: 17.1–70.0%) of time at sea resting on water and 18.2% (range: 2.3–49.6%) foraging. Individuals made 76.4 ± 65.3 dives (range: 8–237) per foraging trip (mean duration 9.0 ± 1.9 s), with dives also recorded during night-time. With the continued miniaturisation of recording devices, the use of combined data-loggers could provide us with further insights into the foraging behaviour of small procellariiforms, helping to better understand interactions with their prey. PMID:26439491
Fernandez-Gonzalez, Rodrigo; Jones, Arthur; Garcia-Rodriguez, Enrique; Yuan Chen, Ping; Idica, Adam; Lockett, Stephen J.; Barcellos-Hoff, Mary Helen; Ortiz-de-Solorzano, Carlos
2002-04-25
We present a new system for simultaneous morphological and molecular analysis of thick tissue samples. The system is composed of a computer assisted microscope and a JAVA-based image display, analysis and visualization program that allows acquisition, annotation, meaningful storage, three-dimensional reconstruction and analysis of structures of interest in thick sectioned tissue specimens. We describe the system in detail and illustrate its use by imaging, reconstructing and analyzing two complete tissue blocks which were differently processed and stained. One block was obtained from a ductal carcinoma in situ (DCIS) lumpectomy specimen and stained alternatively with Hematoxilyn and Eosin (H&E), and with a counterstain and fluorescence in situ hybridization (FISH) to the ERB-B2 gene. The second block contained a fully sectioned mammary gland of a mouse, stained for Histology with H&E. We show how the system greatly reduces the amount of interaction required for the acquisition and analysis and is therefore suitable for studies that require morphologically driven, wide scale (e.g., whole gland) analysis of complex tissue samples or cultures.
Gold nanoparticle-paper as a three-dimensional surface enhanced Raman scattering substrate.
Ngo, Ying Hui; Li, Dan; Simon, George P; Garnier, Gil
2012-06-12
This work investigates the effect of gold nanoparticle (AuNP) addition to paper substrate and examines the ability of these composite materials to amplify the surface enhanced Raman scattering (SERS) signal of a dye adsorbed. Paper has a three-dimensional (3D), porous, and heterogeneous morphology. The manner in which paper adsorbs the nanoparticles is crucial to its SERS properties, particularly with regards to aggregation. In this work, we sought to maintain the same degree of aggregation, while changing the concentration of nanoparticles deposited on paper. We achieved this by dipping paper into AuNP solutions of different, known concentration and found that the initial packing density of AuNPs in solutions was retained on paper with the same degree of aggregation. The surface coverage of AuNPs on paper was found to scale linearly to their concentration profile in solutions. The SERS performances of the AuNP-treated papers were evaluated with 4-aminothiophenol (4-ATP) as the Raman molecule, and their SERS intensities increased linearly with the AuNPs' concentration. Compared to AuNP-treated silicon, the Raman enhancement factor (EF) from paper was relatively higher due to a more uniform and greater degree of adsorption of AuNPs. The effect of the spatial distribution of AuNPs in their substrates on SERS activity was also investigated. In this experiment, the number of AuNPs was kept constant (a 1 μL droplet of AuNPs was deposited on all substrates), and the distribution profile of AuNPs was controlled by the nature of the substrate: paper, silicon, and hydrophobized paper. The AuNP droplet on paper showed the most reproducible and sensitive SERS signal. This highlighted the role of the z-distribution (through film) of AuNPs within the bulk of the paper, producing a 3D multilayer structure to allow inter- and intralayer plasmon coupling, and hence amplifying the SERS signal. The SERS performance of nanoparticle-functionalized paper can thus be optimized by
Hartmann, Sofie Bruun; Mohanty, Soumyaranjan; Skovgaard, Kerstin; Brogaard, Louise; Flagstad, Frederikke Bjergvang; Emnéus, Jenny; Wolff, Anders; Summerfield, Artur; Jungersen, Gregers
2016-01-01
In vitro generation of dendritic-like cells through differentiation of peripheral blood monocytes is typically done using two-dimensional polystyrene culture plates. In the process of optimising cell culture techniques, engineers have developed fluidic micro-devises usually manufactured in materials other than polystyrene and applying three-dimensional structures more similar to the in vivo environment. Polydimethylsiloxane (PDMS) is an often used polymer for lab-on-a-chip devices but not much is known about the effect of changing the culture surface material from polystyrene to PDMS. In the present study the differentiation of porcine monocytes to monocyte-derived dendritic cells (moDCs) was investigated using CD172apos pig blood monocytes stimulated with GM-CSF and IL-4. Monocytes were cultured on surfaces made of two- and three-dimensional polystyrene as well as two- and three-dimensional PDMS and carbonised three-dimensional PDMS. Cells cultured conventionally (on two-dimensional polystyrene) differentiated into moDCs as expected. Interestingly, gene expression of a wide range of cytokines, chemokines, and pattern recognition receptors was influenced by culture surface material and architecture. Distinct clustering of cells, based on similar expression patterns of 46 genes of interest, was seen for cells isolated from two- and three-dimensional polystyrene as well as two- and three-dimensional PDMS. Changing the material from polystyrene to PDMS resulted in cells with expression patterns usually associated with macrophage expression (upregulation of CD163 and downregulation of CD1a, FLT3, LAMP3 and BATF3). However, this was purely based on gene expression level, and no functional assays were included in this study which would be necessary in order to classify the cells as being macrophages. When changing to three-dimensional culture the cells became increasingly activated in terms of IL6, IL8, IL10 and CCR5 gene expression. Further stimulation with LPS resulted
NASA Technical Reports Server (NTRS)
Gibson, S. G.
1983-01-01
A system of computer programs was developed to model general three dimensional surfaces. Surfaces are modeled as sets of parametric bicubic patches. There are also capabilities to transform coordinates, to compute mesh/surface intersection normals, and to format input data for a transonic potential flow analysis. A graphical display of surface models and intersection normals is available. There are additional capabilities to regulate point spacing on input curves and to compute surface/surface intersection curves. Input and output data formats are described; detailed suggestions are given for user input. Instructions for execution are given, and examples are shown.
NASA Astrophysics Data System (ADS)
Xu, Ye-Chuan; Liu, Bang-Gui
2009-11-01
In this paper we present a unified phase-field model for non-equilibrium growths of various three-dimensional metal islands on insulating surfaces. We introduce a phase-field variable to distinguish the island from the non-island regions and substrate and a density variable to describe local density of deposited adatoms. Two partial differential equations with appropriate boundary conditions, as the governing equations, are used to describe the evolution of the three-dimensional metal islands and the diffusion of adatoms. We solve the equations by using an adaptive mesh refinement method so that we can simulate the non-equilibrium growth of three-dimensional metal islands from tens of nanometers to several micrometers. We investigate the dependence of simulated results on the model parameters and experimental conditions. Equilibrium shape of such islands can be obtained through sufficient post-deposition relaxation. Experimental trends of island size and shape on various scales are obtained with reasonable parameters. This method should be a good approach to non-equilibrium growths of multi-scale three-dimensional metal islands.
Error reduction in three-dimensional metrology combining optical and touch probe data
NASA Astrophysics Data System (ADS)
Gerde, Janice R.; Christens-Barry, William A.
2010-08-01
Analysis of footwear under the Harmonized Tariff Schedule of the United States (HTSUS) is partly based on identifying the boundary ("parting line") between the "external surface area upper" (ESAU) and the sample's sole. Often, that boundary is obscured. We establish the parting line as the curved intersection between the sample outer surface and its insole surface. The outer surface is determined by discrete point cloud coordinates obtained using a laser scanner. The insole surface is defined by point cloud data, obtained using a touch probe device-a coordinate measuring machine (CMM). Because these point cloud data sets do not overlap spatially, a polynomial surface is fitted to the insole data and extended to intersect a mesh fitted to the outer surface point cloud. This line of intersection defines the ESAU boundary, permitting further fractional area calculations to proceed. The defined parting line location is sensitive to the polynomial used to fit experimental data. Extrapolation to the intersection with the ESAU can heighten this sensitivity. We discuss a methodology for transforming these data into a common reference frame. Three scenarios are considered: measurement error in point cloud coordinates, from fitting a polynomial surface to a point cloud then extrapolating beyond the data set, and error from reference frame transformation. These error sources can influence calculated surface areas. We describe experiments to assess error magnitude, the sensitivity of calculated results on these errors, and minimizing error impact on calculated quantities. Ultimately, we must ensure that statistical error from these procedures is minimized and within acceptance criteria.
Lämmerhardt, Nico; Merzsch, Stephan; Ledig, Johannes; Bora, Achyut; Waag, Andreas; Tornow, Marc; Mischnick, Petra
2013-07-01
The huge and intelligent processing power of three-dimensional (3D) biological "processors" like the human brain with clock speeds of only 0.1 kHz is an extremely fascinating property, which is based on a massively parallel interconnect strategy. Artificial silicon microprocessors are 7 orders of magnitude faster. Nevertheless, they do not show any indication of intelligent processing power, mostly due to their very limited interconnectivity. Massively parallel interconnectivity can only be realized in three dimensions. Three-dimensional artificial processors would therefore be at the root of fabricating artificially intelligent systems. A first step in this direction would be the self-assembly of silicon based building blocks into 3D structures. We report on the self-assembly of such building blocks by molecular recognition, and on the electrical characterization of the formed assemblies. First, planar silicon substrates were functionalized with self-assembling monolayers of 3-aminopropyltrimethoxysilane for coupling of oligonucleotides (single stranded DNA) with glutaric aldehyde. The oligonucleotide immobilization was confirmed and quantified by hybridization with fluorescence-labeled complementary oligonucleotides. After the individual processing steps, the samples were analyzed by contact angle measurements, ellipsometry, atomic force microscopy, and fluorescence microscopy. Patterned DNA-functionalized layers were fabricated by microcontact printing (μCP) and photolithography. Silicon microcubes of 3 μm edge length as model objects for first 3D self-assembly experiments were fabricated out of silicon-on-insulator (SOI) wafers by a combination of reactive ion etching (RIE) and selective wet etching. The microcubes were then surface-functionalized using the same protocol as on planar substrates, and their self-assembly was demonstrated both on patterned silicon surfaces (88% correctly placed cubes), and to cube aggregates by complementary DNA
NASA Astrophysics Data System (ADS)
Gaertner, Maria; Cimalla, Peter; Knels, Lilla; Meissner, Sven; Koch, Edmund
2011-03-01
Optical coherence tomography (OCT), as a non-invasive technique for studying tissue morphology, is widely used in in vivo studies, requiring high resolution and fast three-dimensional imaging. Based on light scattering it reveals micrometer sized substructures of the samples due to changes in their optical properties and therefore allows quantification of the specimen's geometry. Utilizing fluorescence microscopy further information can be obtained from molecular compositions embedded in the investigated object. Fluorescent markers, specifically binding to the substance of interest, reveal the sample's chemical structure and give rise to functional studies. This research presents the application of a combined OCT and laser scanning confocal microscopy (LSCM) system to investigate structural details in lung tissue. OCT reveals the three-dimensional morphology of the alveoli whereas fluorescence detection, arising from the fluorophore Sulforhodamin B (SRB) which is binding to elastin, shows the elastic meshwork of the organs extracellular matrix. Different plains of fluorescence can be obtained by using a piezo driven objective and exploiting the confocal functionality of the setup. Both techniques combined in one optical system not only ease the experimental procedure but also contribute to a thorough description of tissue's morphology and chemical composition.
Andrianov, Alexey; Anashkina, Elena; Kim, Arkady; Meyerov, Iosif; Lebedev, Sergey; Sergeev, Alexander; Mourou, Gerard
2014-11-17
We developed a three-dimensional numerical model of Large-Mode-Area chirped pulse fiber amplifiers which includes nonlinear beam propagation in nonuniform multimode waveguides as well as gain spectrum dynamics in quasi-three-level active ions. We used our model in tapered Yb-doped fiber amplifiers and showed that single-mode propagation is maintained along the taper even in the presence of strong Kerr nonlinearity and saturated gain, allowing extraction of up to 3 mJ of output energy in 1 ns pulse. Energy scaling and its limitation as well as the influence of fiber taper bending and core irregularities on the amplifier performance were studied. We also investigated numerically the capabilities for compression and coherent combining of up to 36 perturbed amplifying channels and showed more than 70% combining efficiency, even with up to 11% of high-order modes in individual channels. PMID:25402067
NASA Astrophysics Data System (ADS)
Shen, Shuwei; Zhao, Zuhua; Wang, Haili; Han, Yilin; Dong, Erbao; Liu, Bin; Liu, Wendong; Cromeens, Barrett; Adler, Brent; Besner, Gail; Ray, William; Hoehne, Brad; Xu, Ronald
2016-03-01
Appropriate surgical planning is important for improved clinical outcome and minimal complications in many surgical operations, such as a conjoined twin separation surgery. We combine 3D printing with casting and assembling to produce a solid phantom of high fidelity to help surgeons for better preparation of the conjoined twin separation surgery. 3D computer models of individual organs were reconstructed based on CT scanned data of the conjoined twins. The models were sliced, processed, and converted to an appropriate format for Fused Deposition Modeling (FDM). The skeletons of the phantom were printed directly by FDM using Acrylonitrile-Butadiene-Styrene (ABS) material, while internal soft organs were fabricated by casting silicon materials of different compositions in FDM printed molds. The skeleton and the internal organs were then assembled with appropriate fixtures to maintain their relative positional accuracies. The assembly was placed in a FMD printed shell mold of the patient body for further casting. For clear differentiation of different internal organs, CT contrast agents of different compositions were added in the silicon cast materials. The produced phantom was scanned by CT again and compared with that of the original computer models of the conjoined twins in order to verify the structural and positional fidelity. Our preliminary experiments showed that combining 3D printing with casting is an effective way to produce solid phantoms of high fidelity for the improved surgical planning in many clinical applications.
Quadratic resonance in the three-dimensional oscillations of inviscid drops with surface tension
NASA Technical Reports Server (NTRS)
Natarajan, R.; Brown, R. A.
1986-01-01
The moderate-amplitude, three-dimensional oscillations of an inviscid drop are described in terms of spherical harmonics. Specific oscillation modes are resonantly coupled by quadratic nonlinearities caused by inertia, capillarity, and drop deformation. The equations describing the interactions of these modes are derived from the variational principle for the appropriate Lagrangian by expressing the modal amplitudes to be functions of a slow time scale and by preaveraging the Lagrangian over the time scale of the primary oscillations. Stochastic motions are predicted for nonaxisymmetric deformations starting from most initial conditions, even those arbitrarily close to the axisymmetric shapes. The stochasticity is characterized by a redistribution of the energy contained in the initial deformation over all the degrees of freedom of the interacting modes.
Semianalytical series solutions for three-dimensional groundwater-surface water interaction
NASA Astrophysics Data System (ADS)
Ameli, Ali A.; Craig, James R.
2014-05-01
A semianalytical grid-free series solution method is presented for modeling 3-D steady state free boundary groundwater-surface water exchange in geometrically complex stratified aquifers. Continuous solutions for pressure in the subsurface are determined semianalytically, as is the location of the water table surface. Mass balance is satisfied exactly over the entire domain except along boundaries and interfaces between layers, where errors are shown to be acceptable. The solutions are derived and demonstrated on a number of test cases and the errors are assessed and discussed. This accurate and grid-free scheme can also be a helpful tool for providing insight into lake-aquifer and stream-aquifer interactions. Here it is used to assess the impact of lake sediment geometry and properties on lake-aquifer interactions. Various combinations of lake sediment are considered and the appropriateness of the Dupuit-Forchheimer approximation for simulating lake bottom flux distribution is investigated. In addition, the method is applied to a test problem of surface seepage flows from a complex topographic surface; this test case demonstrated the method's efficacy for simulating physically realistic domains.
A laminar cortical model of stereopsis and three-dimensional surface perception.
Grossberg, Stephen; Howe, Piers D L
2003-03-01
A laminar cortical model of stereopsis and later stages of 3D surface perception is developed and simulated. The model describes how initial stages of monocular and binocular oriented filtering interact with later stages of 3D boundary formation and surface filling-in in the lateral geniculate nucleus and cortical areas V1, V2, and V4. In particular, it details how interactions between layers 4, 3B, and 2/3A in V1 and V2 contribute to stereopsis, and clarifies how binocular and monocular information combine to form 3D boundary and surface representations. Along the way, the model modifies and significantly extends the disparity energy model. Neural explanations are given for psychophysical data concerning: contrast variations of dichoptic masking and the correspondence problem, the effect of interocular contrast differences on stereoacuity, Panum's limiting case, the Venetian blind illusion, stereopsis with polarity-reversed stereograms, da Vinci stereopsis, and various lightness illusions. By relating physiology to psychophysics, the model provides new functional insights and predictions about laminar cortical architecture. PMID:12639606
NASA Astrophysics Data System (ADS)
Zhang, X.; Stroud, D.
1993-09-01
We calculate the ac dielectric function of a model Drude metal-insulator composite, using a three-dimensional (d=3) transfer-matrix algorithm. The real part of the effective conductivity, Rege(ω), reveals (i) a Drude peak that appears only above the percolation threshold pc; and (ii) a broad spectrum of surface-plasmon resonances whose lower edge approaches zero frequency at pc. Sufficiently near pc, the dielectric function is consistent with an expected scaling form previously verified in d=2. The surface-plasmon spectrum resembles effective-medium predictions except for a weak but persistent peak near 0.4ω/ωp.
Faber, Derrek M.; Weiland, Mark A.; Moursund, Robert; Carlson, Thomas J.; Adams, Noah; Rhondorf, D.
2001-05-01
This report describes tests conducted at Bonneville Dam on the Columbia River in the spring of 2000 using three-dimensional acoustic telemetry and computational fluid dynamics hydraulic modeling to observe the response of outmigrating juvenile steelhead and yearling chinook to a prototype surface collector installed at the Powerhouse. The study described in this report was one of several conducted for the U.S. Army Corps of Engineers to prepare a decision document on which of two bypass methods: surface flow bypass or extended-length submersible bar screens to use to help smolts pass around Bonneville dams without going through the turbines.
NASA Technical Reports Server (NTRS)
Hartley, Dana; Prinn, Ronald
1993-01-01
The paper investigates the feasibility of using an inverse method based on a linear Kalman filter in a three-dimensional atmospheric transport model, for the determination of regional surface fluxes with rapid convergence, using data from a finite number of observation sites. It was found that the inverse method used was capable to accurately determine regional surface fluxes using the present ALE/GALE sites, and to converge to the correct solution within a year or two, using initial conditions very different from the final solution.
Three-dimensional stress intensity factor analysis of a surface crack in a high-speed bearing
NASA Technical Reports Server (NTRS)
Ballarini, Roberto; Hsu, Yingchun
1990-01-01
The boundary element method is applied to calculate the stress intensity factors of a surface crack in the rotating inner raceway of a high-speed roller bearing. The three-dimensional model consists of an axially stressed surface cracked plate subjected to a moving Hertzian contact loading. A multidomain formulation and singular crack-tip elements were employed to calculate the stress intensity factors accurately and efficiently for a wide range of configuration parameters. The results can provide the basis for crack growth calculations and fatigue life predictions of high-performance rolling element bearings that are used in aircraft engines.
NASA Astrophysics Data System (ADS)
Huang, Shenghai; Piao, Zhonglie; Zhu, Jiang; Lu, Fan; Chen, Zhongping
2015-07-01
Microvascular network of the retina plays an important role in diagnosis and monitoring of various retinal diseases. We propose a three-dimensional (3-D) segmentation method with intensity-based Doppler variance (IBDV) based on swept-source optical coherence tomography. The automatic 3-D segmentation method is used to obtain seven surfaces of intraretinal layers. The microvascular network of the retina, which is acquired by the IBDV method, can be divided into six layers. The microvascular network of the six individual layers is visualized, and the morphology and contrast images can be improved by using the segmentation method. This method has potential for earlier diagnosis and precise monitoring in retinal vascular diseases.
Huang, Shenghai; Piao, Zhonglie; Zhu, Jiang; Lu, Fan; Chen, Zhongping
2015-01-01
Abstract. Microvascular network of the retina plays an important role in diagnosis and monitoring of various retinal diseases. We propose a three-dimensional (3-D) segmentation method with intensity-based Doppler variance (IBDV) based on swept-source optical coherence tomography. The automatic 3-D segmentation method is used to obtain seven surfaces of intraretinal layers. The microvascular network of the retina, which is acquired by the IBDV method, can be divided into six layers. The microvascular network of the six individual layers is visualized, and the morphology and contrast images can be improved by using the segmentation method. This method has potential for earlier diagnosis and precise monitoring in retinal vascular diseases. PMID:26169790
NASA Technical Reports Server (NTRS)
Komornicki, A.; Morokuma, K.; George, T. F.
1977-01-01
The role of electron transitions in collisions is studied for the F + H2 reaction by combining quasi-classical Monte Carlo trajectories with a semiclassical decoupling approximation for the electron transitions. Attention is directed at the reaction of excited state F atoms reacting to form ground state products; the reactants are initiated in either of two spin-orbit states of the atom with the diatom in the ground vibrational state and the lowest four rotational states, at relative translational energies of 0.1, 0.2 and 0.3 eV. Even if the reactants are initiated on the excited state surface, the reactive cross sections (which are classically forbidden) are significant. The major dynamical effects of the excited state reaction are the flow of reactant electronic energy into product internal energy.
An interactive user-friendly approach to surface-fitting three-dimensional geometries
NASA Technical Reports Server (NTRS)
Cheatwood, F. Mcneil; Dejarnette, Fred R.
1988-01-01
A surface-fitting technique has been developed which addresses two problems with existing geometry packages: computer storage requirements and the time required of the user for the initial setup of the geometry model. Coordinates of cross sections are fit using segments of general conic sections. The next step is to blend the cross-sectional curve-fits in the longitudinal direction using general conics to fit specific meridional half-planes. Provisions are made to allow the fitting of fuselages and wings so that entire wing-body combinations may be modeled. This report includes the development of the technique along with a User's Guide for the various menus within the program. Results for the modeling of the Space Shuttle and a proposed Aeroassist Flight Experiment geometry are presented.
Rapid three-dimensional chromoscan system of body surface based on digital fringe projection
NASA Astrophysics Data System (ADS)
Wei, Bin; Liang, Jin; Li, Jie; Ren, Maodong
2015-09-01
This paper proposes a rapid body scanning system that uses optical digital fringe projection method. Twelve cameras and four digital projectors are placed around the human body from four different directions, so that the body surface threedimensional( 3D) point cloud data can be scanned in 5~8 seconds. It can overcome many difficulties in a traditional measurement method, such as laser scanning causes damage to human eye and low splicing accuracy using structured white light scanning system. First, an accurate calibration method based on close-range photogrammetry, is proposed and verified for calibrating the twelve cameras and the four digital projectors simultaneously, where a 1m×2m plate as calibration target with feature points pasted on its two-sides is used. An experiment indicates that the proposed calibration method, with a re-projection error less than 0.05pixels, has a considerable accuracy. The whole 3D body surface color point cloud data can be measured without splice different views of point cloud, because of the high accuracy calibration results. Then, in order to measure the whole body point cloud data with high accuracy, a combination of single and stereo camera measuring method, based on digital fringe projection, has presented to calculating 3D point cloud data. At last, a novel body chromoscan system is developed and a human body 3D digital model was scanned, by which a physical body model was manufactured using 3D printing technology.
Direct Observation of Three-dimensional Electroconvective Vortices on a Charge Selective Surface
NASA Astrophysics Data System (ADS)
Kwak, Rhokyun; Han, Jongyoon; Lee, Taikjin; Kwak, Ho-Young
2015-11-01
We present a visualization of three-dimensional electroconvective vortices (EC) by ion concentration polarization (ICP) on a cation selective membrane. The vortices are initiated between two transparent Nafion membranes under no-shear/shear conditions with various applied voltages and flow velocities. Fluorescent imaging and spatial Fourier transform allow us to capture vortex structures. In this 3-D system, EC shows three distinguished structures: i) polygonal shapes with no-shear and ii) transverse and/or iii) longitudinal vortex rolls with shear flow, which is reminiscent of 3-D Rayleigh-Benard instability. Under shear flow, as flow velocity (Reynolds number: Re) increases or voltage (electric Rayleigh number: Ra) decreases, pure longitudinal vortices are presented; in the inverse case, transverse vortices are also formed. It is noteworthy that if we confine EC in quasi 2-D system with high Ra (>10,000), we obtain pure transverse vortices; high Ra induces chaotic EC in this 3-D system, instead of 2-D stable transverse vortices. To the best of our knowledge, this is the first direct observation of 3-D EC, which will occur in realistic electrochemical devices, e.g. electrodialysis.
NASA Astrophysics Data System (ADS)
Smoot, N. Christian; King, Robert E.
1993-01-01
Slump and debris slides form on seamounts as they grow, age, and are transported across the sea floor. Slump scars, evident as amphitheater headwalls, are a good morphological indicator where a landslide has occurred. Radical changes in the lower flank slope angles are also good indicators. Debris flows can be surmised by hummocky topography, with the larger blocks being nearer the main edifice. A cursory inspection of the Pacific plate from younger to older shows: (1) the Hawaiian-Emperor Ridge from Loihi to Suiko at 65 Ma, where the lower flank slopes increase with age, (2) Mammerickx seamount in the Mapmakers on 140 Ma crust, out of the fractured region, still showing moats and having no sign of landslides, (3) Castor and Pollux guyots of the Michelson Ridge on 150 Ma crust, where the debris field size is added to or overprinted by later volcanics, to (4) Hunk, Jennings, and Jaybee guyots in the Marcus-Wake seamounts on 160 Ma crust, where later fracture zone formation may have helped form landslides. None of the older seamounts have been dated. Three-dimensional views aid in the location and description of landslides.
Cell volume control at a surface for three-dimensional grid generation packages
NASA Technical Reports Server (NTRS)
Alter, Stephen J.; Weilmuenster, Kenneth J.
1992-01-01
An alternate method of calculating the cell size for orthogonality control in the solution of Poisson's 3D space equations is presented. The method provides the capability to enforce a better initial guess for the grid distribution required for boundary layer resolution. This grid point distribution is accomplished by enforcing grid spacing from a grid block boundary where orthogonality is required. The actual grid spacing or cell size for that boundary is determined by the two or four adjacent boundaries in the grid block definition, which are two dimensional grids. These two dimensional grids are in turn defined by the user using insight into the flow field and boundary layer characteristics. The adjoining boundaries are extended using a multifunctional blending scheme, with user control of the blending and interpolating functions to be used. This grid generation procedure results in an enhanced computational fluid dynamics calculation by allowing a quicker resolution of the configuration's boundary layer and flow field and by limiting the number of grid re-adaptations. The cell size specification calculation was applied to a variety of configurations ranging from axisymmetric to complex three-dimensional configurations. Representative grids are shown for the Space Shuttle and the Langley Lifting Body (HL-20).
Hammel, P.C.; Moore, G.; Roukes, M.; Zhenyong Zhang
1996-10-01
This is the final report of a two-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The project successfully developed a magnetic resonance force microscope (MRFM) instrument to mechanically detect magnetic resonance signals. This technique provides an intrinsically subsurface, chemical-species-specific probe of structure, constituent density and other properties of materials. As in conventional magnetic resonance imaging (MRI), an applied magnetic field gradient selects a well defined volume of the sample for study. However mechanical detection allows much greater sensitivity, and this in turn allows the reduction of the size of the minimum resolvable volume. This requires building an instrument designed to achieve nanometer-scale resolution at buried semiconductor interfaces. High-resolution, three-dimensional depth profiling of semiconductors is critical in the development and fabrication of semiconductor devices. Currently, there is no capability for direct, high-resolution observation and characterization of dopant density, and other critical features of semiconductors. The successful development of MRFM in conjunction with modifications to improve resolution will enable for the first time detailed structural and electronic studies in doped semiconductors and multilayered nanoelectronic devices, greatly accelerating the current pace of research and development.
Wang, Haiyan; Zhou, Yuexi; Yuan, Quan; Zhao, Hua; Dai, Xin
2014-01-01
The bacterial morphology and diversity in the reactors of a combined autotrophic nitritation and sulfur-carbon three-dimensional-electrode denitrification (CANSCTED) process operating under steady-state conditions were investigated by scanning electron microscopy and partial 16S rDNA cloning and sequencing. The CANSCTED process consisted of two parts, i.e., the nitritation membrane bioreactor (NMBR) and the sulfur-carbon three-dimensional-electrode denitrification reactor (SCTED). When the influent NH₄(+) concentration of NMBR ranged from 854 to 1086 mg N L(-1), with about 50% NH₄(+) removal efficiency and NO₂(-) accumulation rate, the spherical and spheroidal ammonia-oxidizing bacteria were predominant, with community successions of β-Proteobacteria (60.0%), Bacteroidetes (28.3%) and Chloroflexi (11.7%). The NMBR effluent with 429∼543 mg N L(-1) NH₄(+) and 519∼578 mg N L(-1) NO₂(-) was continuously supplied to SCTED for sulfur denitrification, bioelectrochemical hydrogen denitrification, and anaerobic ammonium oxidation. The predominant bacterial community successions were β-Proteobacteria (78.3%) and ϵ-Proteobacteria (21.7%). When the SCTED influent was supplied with only NO₂(-) (412-525 mg N L(-1)) as nitrogen substrate, the predominant bacteria in SCTED were short-bacilliform and spheroidal denitrification bacteria, β-Proteobacteria (82.0%), ϵ-Proteobacteria (16.4%) and γ-Proteobacteria (1.6%). Although the predominant bacterial communities were both β-Proteobacteria and ϵ-Proteobacteria in SCTED, the species and quantity of each community varied with the change of SCTED influent composition, which indicated that the composition influence the bacterial morphology and diversity in SCTED. PMID:24117082
An equivalent body surface charge model representing three-dimensional bioelectrical activity
NASA Technical Reports Server (NTRS)
He, B.; Chernyak, Y. B.; Cohen, R. J.
1995-01-01
A new surface-source model has been developed to account for the bioelectrical potential on the body surface. A single-layer surface-charge model on the body surface has been developed to equivalently represent bioelectrical sources inside the body. The boundary conditions on the body surface are discussed in relation to the surface-charge in a half-space conductive medium. The equivalent body surface-charge is shown to be proportional to the normal component of the electric field on the body surface just outside the body. The spatial resolution of the equivalent surface-charge distribution appears intermediate between those of the body surface potential distribution and the body surface Laplacian distribution. An analytic relationship between the equivalent surface-charge and the surface Laplacian of the potential was found for a half-space conductive medium. The effects of finite spatial sampling and noise on the reconstruction of the equivalent surface-charge were evaluated by computer simulations. It was found through computer simulations that the reconstruction of the equivalent body surface-charge from the body surface Laplacian distribution is very stable against noise and finite spatial sampling. The present results suggest that the equivalent body surface-charge model may provide an additional insight to our understanding of bioelectric phenomena.
NASA Astrophysics Data System (ADS)
Ivanov, Pavlo; Taylor, Richard J. E.; Li, Guangrui; Childs, David T. D.; Khamas, Salam; Sarma, Jayanta; Erdelyi, Robertus; Hogg, Richard A.
2016-03-01
We investigate the beam divergence in far-field region, diffraction loss and optical confinement factors of all-semiconductor and void-semiconductor photonic-crystal surface-emitting lasers (PCSELs), containing either InGaP/GaAs or InGaP/air photonic crystals using a three-dimensional FDTD model. We explore the impact of changing the PC hole shape, size, and lattice structure in addition to the choice of all-semiconductor or void-semiconductor designs. We discuss the determination of the threshold gain from the diffraction losses, and explore limitations to direct modulation of the PCSEL.
NASA Astrophysics Data System (ADS)
Cao, Z.; Walsh, J. L.; Kong, M. G.
2009-01-01
This letter reports on electrical and optical characteristics of a ten-channel atmospheric pressure glow discharge jet array in parallel electric and gas flow fields. Challenged with complex three-dimensional substrates including surgical tissue forceps and sloped plastic plate of up to 15°, the jet array is shown to achieve excellent jet-to-jet uniformity both in time and in space. Its spatial uniformity is four times better than a comparable single jet when both are used to treat a 15° sloped substrate. These benefits are likely from an effective self-adjustment mechanism among individual jets facilitated by individualized ballast and spatial redistribution of surface charges.
NASA Astrophysics Data System (ADS)
Seshadri, Rajeswari; Sabaskar, J.
2016-03-01
The present research study deals with the steady flow and heat transfer of a viscoelastic fluid over a stretching surface in two lateral directions with a magnetic field applied normal to the surface. The fluid far away from the surface is ambient and the motion in the flow field is caused by stretching surface in two directions. This result is a three-dimensional flow instead of two-dimensional as considered by many authors. Self-similar solutions are obtained numerically. For some particular cases, closed form analytical solutions are also obtained. The numerical calculations show that the skin friction coefficients in x- and y-directions and the heat transfer coefficient decrease with the increasing elastic parameter, but they increase with the stretching parameter. The heat transfer coefficient for the constant heat flux case is higher than that of the constant wall temperature case.
Zhuo, Shuangmu E-mail: hanry-yu@nuhs.edu.sg; Yan, Jie; Kang, Yuzhan; Peng, Qiwen; and others
2014-07-14
Various structural features on the liver surface reflect functional changes in the liver. The visualization of these surface features with molecular specificity is of particular relevance to understanding the physiology and diseases of the liver. Using multi-photon microscopy (MPM), we have developed a label-free, three-dimensional quantitative and sensitive method to visualize various structural features of liver surface in living rat. MPM could quantitatively image the microstructural features of liver surface with respect to the sinuosity of collagen fiber, the elastic fiber structure, the ratio between elastin and collagen, collagen content, and the metabolic state of the hepatocytes that are correlative with the pathophysiologically induced changes in the regions of interest. This study highlights the potential of this technique as a useful tool for pathophysiological studies and possible diagnosis of the liver diseases with further development.
Direct Observation of the Fermi Arc Surface State in the Three-Dimensional Dirac Semimetal Na3Bi
NASA Astrophysics Data System (ADS)
Liang, Aiji; Wang, Zhijun; Chen, Chaoyu; Shi, Youguo; Yi, Hemian; Feng, Ya; Xie, Zhuojin; He, Shaolong; He, Junfeng; Peng, Yingying; Liu, Xu; Liu, Yan; Zhao, Lin; Liu, Guodong; Zhang, Jun; Nakatake, M.; Arita, M.; Shimada, K.; Namatame, H.; Taniguchi, M.; Xu, Zuyan; Chen, Chuangtian; Dai, Xi; Fang, Zhong; Zhou, Xingjiang
2015-03-01
The three dimensional (3D) Dirac semimetals have linearly dispersive 3D Dirac nodes where the conduction and valence bands connect to each other. Here we report the direct observation of the linearly dispersive 3D bulk Dirac points at the natural (001) cleaving surface of Na3Bi single crystal by high resolution ARPES. In addition, we have directly observed two separated 3D bulk Dirac nodes by elaborately cleaving Na3Bi samples at a non-natural-cleavage (100) crystalline surface. We further unveil the unusual Fermi-arc surface states connecting the two 3D Dirac nodes. At this unique (100) crystalline surface, the identification of the 3D Dirac semimetal state in Na3Bi paves the way for systematically exploring rich exotic topological physics such as topological insulator and Weyl semimetal state.
NASA Astrophysics Data System (ADS)
Zhuo, Shuangmu; Yan, Jie; Kang, Yuzhan; Xu, Shuoyu; Peng, Qiwen; So, Peter T. C.; Yu, Hanry
2014-07-01
Various structural features on the liver surface reflect functional changes in the liver. The visualization of these surface features with molecular specificity is of particular relevance to understanding the physiology and diseases of the liver. Using multi-photon microscopy (MPM), we have developed a label-free, three-dimensional quantitative and sensitive method to visualize various structural features of liver surface in living rat. MPM could quantitatively image the microstructural features of liver surface with respect to the sinuosity of collagen fiber, the elastic fiber structure, the ratio between elastin and collagen, collagen content, and the metabolic state of the hepatocytes that are correlative with the pathophysiologically induced changes in the regions of interest. This study highlights the potential of this technique as a useful tool for pathophysiological studies and possible diagnosis of the liver diseases with further development.
Three-Dimensional Surface Parameters and Multi-Fractal Spectrum of Corroded Steel
Shanhua, Xu; Songbo, Ren; Youde, Wang
2015-01-01
To study multi-fractal behavior of corroded steel surface, a range of fractal surfaces of corroded surfaces of Q235 steel were constructed by using the Weierstrass-Mandelbrot method under a high total accuracy. The multi-fractal spectrum of fractal surface of corroded steel was calculated to study the multi-fractal characteristics of the W-M corroded surface. Based on the shape feature of the multi-fractal spectrum of corroded steel surface, the least squares method was applied to the quadratic fitting of the multi-fractal spectrum of corroded surface. The fitting function was quantitatively analyzed to simplify the calculation of multi-fractal characteristics of corroded surface. The results showed that the multi-fractal spectrum of corroded surface was fitted well with the method using quadratic curve fitting, and the evolution rules and trends were forecasted accurately. The findings can be applied to research on the mechanisms of corroded surface formation of steel and provide a new approach for the establishment of corrosion damage constitutive models of steel. PMID:26121468
NASA Astrophysics Data System (ADS)
Roy, Sthitadhi; Roychowdhury, Krishanu; Das, Sourin
2016-07-01
We show that the surface states of pristine 3D topological insulators (TIs) are analogs of ferromagnetic half metals due to complete polarization of an emergent momentum independent pseudospin (SU(2)) degree of freedom on the surface. To put this claim on firm footing, we present results for TI surfaces perpendicular to the crystal growth axis, which clearly show that the tunneling conductance between two such TI surfaces of the same TI material is dominated by this half metallic behavior leading to physics reminiscent of a spin-valve. Further using the generalized tunnel magnetoresistance derived in this work we also study the tunneling current between arbitrary TI surfaces. We also perform a comprehensive study of the effect of all possible surface potentials allowed by time reversal symmetry on this spin-valve effect and show that it is robust against most of such potentials.
Three-dimensional ray tracing on Delaunay-based reconstructed surfaces.
Ortiz, Sergio; Siedlecki, Damian; Remon, Laura; Marcos, Susana
2009-07-10
A method of ray tracing for free-form optical surfaces has been developed. The ray tracing through such surfaces is based on Delaunay triangulation of the discrete data of the surface and is related to finite-element modeling. Some numerical examples of applications to analytical, noisy, and experimental free-form surfaces (in particular, a corneal topography map) are presented. Ray-tracing results (i.e., spot diagram root-mean-square error) with the new method are in agreement with those obtained using a modal fitting of the surface, for sampling densities higher than 40 x 40 elements. The method competes in flexibility, simplicity, and computing times with standard methods for surface fitting and ray tracing. PMID:19593339
NASA Astrophysics Data System (ADS)
Hong, Eun-Soo; Kwon, Tae-Hyuk; Song, Ki-Il; Cho, Gye-Chun
2016-01-01
The present study explores the degradation characteristics and scale of unevenness (small-scale roughness) on sheared rock joint surfaces at a low-stress regime. While the degradation characteristics of unevenness and the normal stress are mutually interrelated, an understanding of the degradation patterns of the three-dimensional roughness of rock joints is one of the important components needed to identify asperity failure characteristics and to quantify the role of damaged unevenness in establishing a shear strength model. A series of direct shear tests was performed on three-dimensional artificial rock joint surfaces at different normal stress levels. After shearing, the spatial distributions and statistical parameters of degraded roughness were analysed for the different normal stress levels. The length and area of the degraded zones showed bell-shaped distributions in a logarithmic scale, and the dominant scale (or the most frequently occurring scale) of the damaged asperities (i.e., unevenness) ranged from approximately, 0.5 to 5.0 mm in length and 0.1-10 mm2 in area. This scale of the damaged unevenness was consistent regardless of the level of normal stress. It was also found that the relative area of damaged unevenness on a given joint area, and thus the contribution of the mechanical asperity failure component to shear strength increased as normal stress increased.
NASA Technical Reports Server (NTRS)
Roth, Don J.; Whalen, Mike F.; Hendricks, J. Lynne; Bodis, James R.
2001-01-01
To interface with other solids, many surfaces are engineered via methods such as plating, coating, and machining to produce a functional surface ensuring successful end products. In addition, subsurface properties such as hardness, residual stress, deformation, chemical composition, and microstructure are often linked to surface characteristics. Surface topography, therefore, contains the signatures of the surface and possibly links to volumetric properties, and as a result serves as a vital link between surface design, manufacturing, and performance. Hence, surface topography can be used to diagnose, monitor, and control fabrication methods. At the NASA Glenn Research Center, the measurement of surface topography is important in developing high-temperature structural materials and for profiling the surface changes of materials during microgravity combustion experiments. A prior study demonstrated that focused air-coupled ultrasound at 1 MHz could profile surfaces with a 25-m depth resolution and a 400-m lateral resolution over a 1.4-mm depth range. In this work, we address the question of whether higher frequency focused water-coupled ultrasound can improve on these specifications. To this end, we employed 10- and 25-MHz focused ultrasonic transducers in the water-coupled mode. The surface profile results seen in this investigation for 25-MHz water-coupled ultrasound, in comparison to those for 1-MHz air-coupled ultrasound, represent an 8 times improvement in depth resolution (3 vs. 25 m seen in practice), an improvement of at least 2 times in lateral resolution (180 vs. 400 m calculated and observed in practice), and an improvement in vertical depth range of 4 times (calculated).
NASA Astrophysics Data System (ADS)
de Michele, Marcello; Raucoules, Daniel; de Sigoyer, Julia; Pubellier, Manuel; Lasserre, Cecile; Pathier, Erwan; Klinger, Yann; van der Woerd, Jerome; Chamot-Rooke, Nicolas
2010-05-01
The Sichuan earthquake, Mw 7.9, struck the Longmen Shan range front, in the western Sichuan province, China, on 12 May 2008. It severely affected an area where little historical seismicity and little or no significant active shortening were reported before the earthquake (e.g. Gu et al., 1989; Chen et al., 1994; Gan et al., 2007). The Longmen Shan thrust system bounds the eastern margin of the Tibetan plateau and is considered as a transpressive zone since Triassic time that was reactivated during the India-Asia collision (e.g., Tapponnier and Molnar, 1977, Chen and Wilson 1996; Arne et al., 1997, Godard et al., 2009). However, contrasting geological evidences of sparse thrusting and marked dextral strike-slip faulting during the Quaternary along with high topography (Burchfiel et al., 1995; Densmore et al., 2007) have led to models of dynamically driven and sustained topography (Royden et al., 1997) limiting the role of earthquakes in relief building and leaving the mechanism of long term strain distribution in this area as an open question. Here we combine C and L band Synthetic Aperture Radar (SAR) offsets data from ascending and descending paths to retrieve the three dimensional surface displacement distribution all along the earthquake ruptures of the Sichuan earthquake. For the first time on this earthquake we present near field 3D co-seismic surface displacement, which is an important datum for constraining modelled fault geometry at depth. Our results complement other Interferometric Synthetic Aperture Radar (InSAR) and field analyses in indicating that crustal shortening is one of the main drivers for topography building in the Longmen Shan (Liu-Zeng, 2009; Shen et al., 2009; Hubbard and Shaw, 2009). Moreover, our results put into evidence a small but significant amount of displacement in the range front that we interpret as due to slip at depth on a blind structure. We verify this hypothesis by inverting the data against a simple elastic dislocation model
Doubek, Gustavo; Sekol, Ryan C.; Li, Jinyang; Ryu, Won -Hee; Gittleson, Forrest S.; Nejati, Siamak; Moy, Eric; Reid, Candy; Carmo, Marcelo; Linardi, Marcelo; et al
2015-12-22
Precise control over catalyst surface composition and structure is necessary to improve the function of electrochemical systems. To that end, bulk metallic glass (BMG) alloys with atomically dispersed elements provide a highly processable, nanoscale platform for electrocatalysis and surface modification. Here we report on nanostructures of Pt-based BMGs that are modified with various subtractive and additive processes to improve their electrochemical performance.
You Yu; Zhai Pengwang; Kattawar, George W.; Yang Ping
2009-06-01
The hybrid matrix operator, Monte Carlo (HMOMC) method previously reported [Appl. Opt.47, 1063-1071 (2008)APOPAI0003-693510.1364/AO.47.001063] is improved by neglecting higher-order terms in the coupling of the matrix operators and by introducing a dual grid scheme. The computational efficiency for solving the vector radiative transfer equation in a full 3D coupled atmosphere-surface-ocean system is substantially improved, and, thus, large-scale simulations of the radiance distribution become feasible. The improved method is applied to the computation of the polarized radiance field under realistic surface waves simulated by the power spectral density method. To the authors' best knowledge, this is the first time that the polarized radiance field under a dynamic ocean surface and the underwater image of an object above such an ocean surface have been reported.
Doerschner, K.; Boyaci, H.; Maloney, L. T.
2007-01-01
We investigated limits on the human visual system’s ability to discount directional variation in complex lights field when estimating Lambertian surface color. Directional variation in the light field was represented in the frequency domain using spherical harmonics. The bidirectional reflectance distribution function of a Lambertian surface acts as a low-pass filter on directional variation in the light field. Consequently, the visual system needs to discount only the low-pass component of the incident light corresponding to the first nine terms of a spherical harmonics expansion (Basri & Jacobs, 2001; Ramamoorthi & Hanrahan, 2001) to accurately estimate surface color. We test experimentally whether the visual system discounts directional variation in the light field up to this physical limit. Our results are consistent with the claim that the visual system can compensate for all of the complexity in the light field that affects the appearance of Lambertian surfaces. PMID:18053846
Frequency-selective surface acoustic invisibility for three-dimensional immersed objects
NASA Astrophysics Data System (ADS)
Farhat, Mohamed; Chen, Pai-Yen; Guenneau, Sébastien; Enoch, Stefan; Alù, Andrea
2012-11-01
This paper is focused on the study of acoustic metasurface cloaking, based on the use of appropriate ultrathin pseudosurfaces that may act as cloaking devices for a finite range of frequencies. The technique consists in tailoring the appropriate acoustic surface impedance which cancels the scattered field of a diffracting spherical obstacle placed in the trajectory of an impinging acoustical wave. Our numerical simulations of both near and far fields show a significant reduction of scattering cross section for a moderately broad range of frequencies, confirming the effectiveness of surface cloaks (easier to manufacture and less cumbersome than their bulk counterpart). We also go one step further by proposing a realistic structure obtained by quasiperiodically patterning the surface of a spherical layer. The effective properties of the metasurface are obtained in the framework of homogenization theory and confirm this realistic route to surface cloaking for acoustic waves.
A Monte Carlo reflectance model for soil surfaces with three-dimensional structure
NASA Technical Reports Server (NTRS)
Cooper, K. D.; Smith, J. A.
1985-01-01
A Monte Carlo soil reflectance model has been developed to study the effect of macroscopic surface irregularities larger than the wavelength of incident flux. The model treats incoherent multiple scattering from Lambertian facets distributed on a periodic surface. Resulting bidirectional reflectance distribution functions are non-Lambertian and compare well with experimental trends reported in the literature. Examples showing the coupling of the Monte Carlo soil model to an adding bidirectional canopy of reflectance model are also given.
NASA Astrophysics Data System (ADS)
Nguyen, K. L.; Treyssède, F.; Hazard, C.
2015-05-01
Among the numerous techniques of non-destructive evaluation, elastic guided waves are of particular interest to evaluate defects inside industrial and civil elongated structures owing to their ability to propagate over long distances. However for guiding structures buried in large solid media, waves can be strongly attenuated along the guide axis due to the energy radiation into the surrounding medium, usually considered as unbounded. Hence, searching the less attenuated modes becomes necessary in order to maximize the inspection distance. In the numerical modeling of embedded waveguides, the main difficulty is to account for the unbounded section. This paper presents a numerical approach combining a semi-analytical finite element method and a perfectly matched layer (PML) technique to compute the so-called trapped and leaky modes in three-dimensional embedded elastic waveguides of arbitrary cross-section. Two kinds of PML, namely the Cartesian PML and the radial PML, are considered. In order to understand the various spectral objects obtained by the method, the PML parameters effects upon the eigenvalue spectrum are highlighted through analytical studies and numerical experiments. Then, dispersion curves are computed for test cases taken from the literature in order to validate the approach.
Zhu, Zhuo-wei; Que, Li-zhi; Chen, Guo-qing; Xu, Rui-yu; Zhu, Tuo
2015-09-01
Three-dimensional fluorescence spectroscopy coupled with parallel factor analysis and neural network was applied to the year discrimination of mild aroma Chinese liquors. The excitation-emission fluorescence matrices (EEMs) of 120 samples with various years were measured by FLS920 fluorescence spectrometer. The trilinear decomposition of the data array was performed and the loading scores of and the excitation-emission profiles of four components were also obtained. The scores were employed as the inputs of the BP neural networks and the PARAFAC-BP identification model was constructed. 10 samples were collected from 10, 20 and 30 years of liquors respectively, and 30 samples were selected as the test sets. The remaining 90 samples were used as the training sets to build the training model. The year prediction of unknown samples was also carried out, and the prediction accuracy was 90%, 100% and 100%, respectively. Meanwhile, the discrimination analysis method and the multi-way partial least squares discriminant analysis were compared, namely PARAFAC-BP and NPLS-DA. The results indicated that parallel factor combined with the neural network (PARAFAC-BP) has higher prediction accuracy. The proposed method can effectively extract the spectral characteristics, and also reduce the dimension of the input variables of neural network. A good year discrimination result was finally achieved. PMID:26669170
Skinner, B.; Chen, T.; Shklovskii, B. I.
2013-09-15
In the three-dimensional topological insulator (TI), the physics of doped semiconductors exists literally side-by-side with the physics of ultrarelativistic Dirac fermions. This unusual pairing creates a novel playground for studying the interplay between disorder and electronic transport. In this mini-review, we focus on the disorder caused by the three-dimensionally distributed charged impurities that are ubiquitous in TIs, and we outline the effects it has on both the bulk and surface transport in TIs. We present self-consistent theories for Coulomb screening both in the bulk and at the surface, discuss the magnitude of the disorder potential in each case, and present results for the conductivity. In the bulk, where the band gap leads to thermally activated transport, we show how disorder leads to a smaller-than-expected activation energy that gives way to variable-range hopping at low temperatures. We confirm this enhanced conductivity with numerical simulations that also allow us to explore different degrees of impurity compensation. For the surface, where the TI has gapless Dirac modes, we present a theory of disorder and screening of deep impurities, and we calculate the corresponding zero-temperature conductivity. We also comment on the growth of the disorder potential in passing from the surface of the TI into the bulk. Finally, we discuss how the presence of a gap at the Dirac point, introduced by some source of time-reversal symmetry breaking, affects the disorder potential at the surface and the mid-gap density of states.
A three-dimensional phase diagram of growth-induced surface instabilities
NASA Astrophysics Data System (ADS)
Wang, Qiming; Zhao, Xuanhe
2015-03-01
A variety of fascinating morphological patterns arise on surfaces of growing, developing or aging tissues, organs and microorganism colonies. These patterns can be classified into creases, wrinkles, folds, period-doubles, ridges and delaminated-buckles according to their distinctive topographical characteristics. One universal mechanism for the pattern formation has been long believed to be the mismatch strains between biological layers with different expanding or shrinking rates, which induce mechanical instabilities. However, a general model that accounts for the formation and evolution of these various surface-instability patterns still does not exist. Here, we take biological structures at their current states as thermodynamic systems, treat each instability pattern as a thermodynamic phase, and construct a unified phase diagram that can quantitatively predict various types of growth-induced surface instabilities. We further validate the phase diagram with our experiments on surface instabilities induced by mismatch strains as well as the reported data on growth-induced instabilities in various biological systems. The predicted wavelengths and amplitudes of various instability patterns match well with our experimental data. It is expected that the unified phase diagram will not only advance the understanding of biological morphogenesis, but also significantly facilitate the design of new materials and structures by rationally harnessing surface instabilities.
A three-dimensional phase diagram of growth-induced surface instabilities
Wang, Qiming; Zhao, Xuanhe
2015-01-01
A variety of fascinating morphological patterns arise on surfaces of growing, developing or aging tissues, organs and microorganism colonies. These patterns can be classified into creases, wrinkles, folds, period-doubles, ridges and delaminated-buckles according to their distinctive topographical characteristics. One universal mechanism for the pattern formation has been long believed to be the mismatch strains between biological layers with different expanding or shrinking rates, which induce mechanical instabilities. However, a general model that accounts for the formation and evolution of these various surface-instability patterns still does not exist. Here, we take biological structures at their current states as thermodynamic systems, treat each instability pattern as a thermodynamic phase, and construct a unified phase diagram that can quantitatively predict various types of growth-induced surface instabilities. We further validate the phase diagram with our experiments on surface instabilities induced by mismatch strains as well as the reported data on growth-induced instabilities in various biological systems. The predicted wavelengths and amplitudes of various instability patterns match well with our experimental data. It is expected that the unified phase diagram will not only advance the understanding of biological morphogenesis, but also significantly facilitate the design of new materials and structures by rationally harnessing surface instabilities. PMID:25748825
Skyrmion-induced bound states on the surface of three-dimensional topological insulators
NASA Astrophysics Data System (ADS)
Andrikopoulos, Dimitrios; Sorée, Bart; De Boeck, Jo
2016-05-01
The interaction between the surface of a 3D topological insulator and a skyrmion/anti-skyrmion structure is studied in order to investigate the possibility of electron confinement due to the skyrmion presence. Both hedgehog (Néel) and vortex (Bloch) skyrmions are considered. For the hedgehog skyrmion, the in-plane components cannot be disregarded and their interaction with the surface state of the topological insulator (TI) has to be taken into account. A semi-classical description of the skyrmion chiral angle is obtained using the variational principle. It is shown that both the hedgehog and the vortex skyrmion can induce bound states on the surface of the TI. However, the number and the properties of these states depend strongly on the skyrmion type and the skyrmion topological number NSk. The probability densities of the bound electrons are also derived where it is shown that they are localized within the skyrmion region.
NASA Astrophysics Data System (ADS)
Landis, Emily K.; Karnick, Pushpak
2006-02-01
This study uses new three-dimensional imaging techniques to compare the articular curvature of the proximal tibial articular surface of hominoids. It has been hypothesized that the curvature of the anteroposterior contour of the lateral condyle in particular can be used to differentiate humans and apes and reflect locomotor function. This study draws from a large comparative sample of extant hominoids to obtain quantitative curvature data. Three-dimensional models of the proximal tibiae of 26 human, 15 chimpanzee, 15 gorilla, 17 orangutan, 16 gibbon and four Australopithecus fossil casts (AL 129-1b, AL 288-1aq, AL 333x-26, KNM-KP 29285A) were acquired with a Cyberware Model 15 laser digitizer. Curvature analysis was accomplished using a software program developed at Arizona State University's Partnership for Research In Stereo Modeling (PRISM) lab, which enables the user to extract curvature profiles and compute the difference between analogous curves from different specimens. Results indicate that the curvature of chimpanzee, gorilla and orangutan tibiae is significantly different from the curvature of human tibiae, thus supporting the hypothesized dichotomy between humans and great apes. The non-significant difference between gibbons and all other taxa indicates that gibbons have an intermediate pattern of articular curvature. All four Australopithecus tibia were aligned with the great apes.
NASA Technical Reports Server (NTRS)
Barton, Richard J.; Ni, David; Ngo, Phong
2010-01-01
Several prototype ultra-wideband (UWB) impulse-radio (IR) tracking systems are currently under development at NASA Johnson Space Center (JSC). These systems are being studied for use in tracking of Lunar/Mars rovers and astronauts during early exploration missions when satellite navigation systems (such as GPS) are not available. To date, the systems that have been designed and tested are intended only for two-dimensional location and tracking, but these designs can all be extended to three-dimensional tracking with only minor modifications and increases in complexity. In this presentation, we will briefly review the design and performance of two of the current 2-D systems: one designed specifically for short-range, extremely high-precision tracking (approximately 1-2 cm resolution) and the other designed specifically for much longer range tracking with less stringent precision requirements (1-2 m resolution). We will then discuss a new multi-purpose system design based on a simple UWB-IR architecture that can be deployed easily on a planetary surface to support arbitrary three-dimensional localization and tracking applications. We will discuss utilization of this system as an infrastructure to provide both short-range and long-range tracking and analyze the localization performance of the system in several different configurations. We will give theoretical performance bounds for some canonical system configurations and compare these performance bounds with both numerical simulations of the system as well as actual experimental system performance evaluations.
NASA Astrophysics Data System (ADS)
Delbridge, Brent G.; Bürgmann, Roland; Fielding, Eric; Hensley, Scott; Schulz, William H.
2016-05-01
In order to provide surface geodetic measurements with "landslide-wide" spatial coverage, we develop and validate a method for the characterization of 3-D surface deformation using the unique capabilities of the Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) airborne repeat-pass radar interferometry system. We apply our method at the well-studied Slumgullion Landslide, which is 3.9 km long and moves persistently at rates up to ˜2 cm/day. A comparison with concurrent GPS measurements validates this method and shows that it provides reliable and accurate 3-D surface deformation measurements. The UAVSAR-derived vector velocity field measurements accurately capture the sharp boundaries defining previously identified kinematic units and geomorphic domains within the landslide. We acquired data across the landslide during spring and summer and identify that the landslide moves more slowly during summer except at its head, presumably in response to spatiotemporal variations in snowmelt infiltration. In order to constrain the mechanics controlling landslide motion from surface velocity measurements, we present an inversion framework for the extraction of slide thickness and basal geometry from dense 3-D surface velocity fields. We find that the average depth of the Slumgullion Landslide is 7.5 m, several meters less than previous depth estimates. We show that by considering a viscoplastic rheology, we can derive tighter theoretical bounds on the rheological parameter relating mean horizontal flow rate to surface velocity. Using inclinometer data for slow-moving, clay-rich landslides across the globe, we find a consistent value for the rheological parameter of 0.85 ± 0.08.
Jung, H.-S.; Lu, Zhiming; Lee, C.-W.
2011-01-01
Interferometric synthetic aperture radar (InSAR) technique has been successfully used for mapping surface deformations [1-2], but it has been normally limited to a measurement along the radar line-of-sight (LOS) direction. For this reason, it is impossible to determine the north (N-S) component of surface deformation because of using data from near-polar orbiting satellites, and it is not sufficient to resolve the parameters of models for earthquakes and volcanic activities because there is a marked trade-off among model parameters [3]. ?? 2011 KIEES.
NASA Technical Reports Server (NTRS)
Turc, Catalin; Anand, Akash; Bruno, Oscar; Chaubell, Julian
2011-01-01
We present a computational methodology (a novel Nystrom approach based on use of a non-overlapping patch technique and Chebyshev discretizations) for efficient solution of problems of acoustic and electromagnetic scattering by open surfaces. Our integral equation formulations (1) Incorporate, as ansatz, the singular nature of open-surface integral-equation solutions, and (2) For the Electric Field Integral Equation (EFIE), use analytical regularizes that effectively reduce the number of iterations required by iterative linear-algebra solution based on Krylov-subspace iterative solvers.
Three-dimensional low Reynolds number flows with a free surface
NASA Technical Reports Server (NTRS)
Degani, D.; Gutfinger, C.
1977-01-01
The two-dimensional leveling problem (Degani, Gutfinger, 1976) is extended to three dimensions in the case where the flow Re number is very low and attention is paid to the free surface boundary condition with surface tension effects included. The no-slip boundary condition on the wall is observed. The numerical solution falls back on the Marker and Cell (MAC) method (Harlow and Welch, 1965) with the computation region divided into a finite number of stationary rectangular cells (or boxes in the 3-D case) and fluid flow traverses the cells (or boxes).
Surface magnetoplasmons in a structure with a two- and three-dimensional plasma
Chaplik, A. V.
2013-07-15
Collective oscillations of a two-component structure consisting of a plasma half-space with a two-dimensional plasma layer at its boundary in the presence of a magnetic field have been studied. Possible variants of the spectra of surface magnetoplasmons have been analyzed for three main mutual orientations of the magnetic field, wavevector, and normal to the surface. The case of the field parallel to the boundary where the frequency is an odd function of the wavevector has been discussed in detail.
NASA Astrophysics Data System (ADS)
Yi, Longtao; Sun, Tianxi; Wang, Kai; Qin, Min; Yang, Kui; Wang, Jinbang; Liu, Zhiguo
2016-08-01
Confocal three-dimensional micro X-ray fluorescence (3D MXRF) is an excellent surface analysis technology. For a confocal structure, only the X-rays from the confocal volume can be detected. Confocal 3D MXRF has been widely used for analysing elements, the distribution of elements and 3D image of some special samples. However, it has rarely been applied to analysing surface topography by surface scanning. In this paper, a confocal 3D MXRF technology based on polycapillary X-ray optics was proposed for determining surface topography. A corresponding surface adaptive algorithm based on a progressive approximation method was designed to obtain surface topography. The surface topography of the letter "R" on a coin of the People's Republic of China and a small pit on painted pottery were obtained. The surface topography of the "R" and the pit are clearly shown in the two figures. Compared with the method in our previous study, it exhibits a higher scanning efficiency. This approach could be used for two-dimensional (2D) elemental mapping or 3D elemental voxel mapping measurements as an auxiliary method. It also could be used for analysing elemental mapping while obtaining the surface topography of a sample in 2D elemental mapping measurement.
NASA Astrophysics Data System (ADS)
June Zhang, Bong; Kim, Kwang J.
2012-07-01
In this letter, we propose a three dimensional, interconnected alumina nano porous surface (ANPS), which shows significant critical heat flux (CHF) and a reduction of wall superheat. ANPS is versatile in morphology modifications such as thickness and pore diameter and is used to enhance heat transfer. Structurally well-defined, porous wicks are efficient to absorb and spread liquid into a porous matrix. To characterize various surface wetting environments, synthetic approaches of wetting and liquid absorption have been carried out. We have studied the quantitative evaluation of liquid uptake utilizing electrochemical impedance spectroscopy (EIS). The CHF augment trend is well matched with the amount of liquid absorbed into the porous media, pre-determined by the EIS.
NASA Astrophysics Data System (ADS)
Nicolaescu, Dan; Sakai, Shigeki; Gotoh, Yasuhito; Ishikawa, Junzo
2011-07-01
Advanced implantation systems used for semiconductor processing require transportation of quasi-parallel ion beams, which have low energy ( 11B +, 31P +, 75As +, Eion=200-1000 eV). Divergence of the ion beam due to space charge effects can be compensated through injection of electrons into different regions of the ion beam. The present study shows that electron confinement takes place in regions of strong magnetic field such as collimator magnet provided with surface mirror magnetic fields and that divergence of the ion beam passing through such regions is largely reduced. Modeling results have been obtained using Opera3D/Tosca/Scala. Electrons may be provided by collision between ions and residual gas molecules or may be injected by field emitter arrays. The size of surface magnets is chosen such as not to disturb ion beam collimation, making the approach compatible with ion beam systems. Surface magnets may form thin magnetic layers with thickness h=0.5 mm or less. Conditions for spacing of surface magnet arrays for optimal electron confinement are outlined.
Doerschner, K; Boyaci, H; Maloney, L T
2007-12-01
We investigated limits on the human visual system's ability to discount directional variation in complex lights field when estimating Lambertian surface color. Directional variation in the light field was represented in the frequency domain using spherical harmonics. The bidirectional reflectance distribution function of a Lambertian surface acts as a low-pass filter on directional variation in the light field. Consequently, the visual system needs to discount only the low-pass component of the incident light corresponding to the first nine terms of a spherical harmonics expansion [Basri, R., Jacobs, D. (2001). Lambertian reflectance and linear subspaces. In: International Conference on Computer Vision II, pp. 383-390; Ramamoorthi, R., Hanrahan, P., (2001). An efficient representation for irradiance environment maps. SIGGRAPH 01. New York: ACM Press, pp. 497-500] to accurately estimate surface color. We test experimentally whether the visual system discounts directional variation in the light field up to this physical limit. Our results are consistent with the claim that the visual system can compensate for all of the complexity in the light field that affects the appearance of Lambertian surfaces. PMID:18053846
Humans use predictive kinematic models to calibrate visual cues to three-dimensional surface slant.
Scarfe, Peter; Glennerster, Andrew
2014-07-30
When the sensory consequences of an action are systematically altered our brain can recalibrate the mappings between sensory cues and properties of our environment. This recalibration can be driven by both cue conflicts and altered sensory statistics, but neither mechanism offers a way for cues to be calibrated so they provide accurate information about the world, as sensory cues carry no information as to their own accuracy. Here, we explored whether sensory predictions based on internal physical models could be used to accurately calibrate visual cues to 3D surface slant. Human observers played a 3D kinematic game in which they adjusted the slant of a surface so that a moving ball would bounce off the surface and through a target hoop. In one group, the ball's bounce was manipulated so that the surface behaved as if it had a different slant to that signaled by visual cues. With experience of this altered bounce, observers recalibrated their perception of slant so that it was more consistent with the assumed laws of kinematics and physical behavior of the surface. In another group, making the ball spin in a way that could physically explain its altered bounce eliminated this pattern of recalibration. Importantly, both groups adjusted their behavior in the kinematic game in the same way, experienced the same set of slants, and were not presented with low-level cue conflicts that could drive the recalibration. We conclude that observers use predictive kinematic models to accurately calibrate visual cues to 3D properties of world. PMID:25080598
NASA Astrophysics Data System (ADS)
Bulyha, Alena; Heitzinger, Clemens
2011-04-01
In this work, a Monte-Carlo algorithm in the constant-voltage ensemble for the calculation of 3d charge concentrations at charged surfaces functionalized with biomolecules is presented. The motivation for this work is the theoretical understanding of biofunctionalized surfaces in nanowire field-effect biosensors (BioFETs). This work provides the simulation capability for the boundary layer that is crucial in the detection mechanism of these sensors; slight changes in the charge concentration in the boundary layer upon binding of analyte molecules modulate the conductance of nanowire transducers. The simulation of biofunctionalized surfaces poses special requirements on the Monte-Carlo simulations and these are addressed by the algorithm. The constant-voltage ensemble enables us to include the right boundary conditions; the dna strands can be rotated with respect to the surface; and several molecules can be placed in a single simulation box to achieve good statistics in the case of low ionic concentrations relevant in experiments. Simulation results are presented for the leading example of surfaces functionalized with pna and with single- and double-stranded dna in a sodium-chloride electrolyte. These quantitative results make it possible to quantify the screening of the biomolecule charge due to the counter-ions around the biomolecules and the electrical double layer. The resulting concentration profiles show a three-layer structure and non-trivial interactions between the electric double layer and the counter-ions. The numerical results are also important as a reference for the development of simpler screening models.
Humans Use Predictive Kinematic Models to Calibrate Visual Cues to Three-Dimensional Surface Slant
Glennerster, Andrew
2014-01-01
When the sensory consequences of an action are systematically altered our brain can recalibrate the mappings between sensory cues and properties of our environment. This recalibration can be driven by both cue conflicts and altered sensory statistics, but neither mechanism offers a way for cues to be calibrated so they provide accurate information about the world, as sensory cues carry no information as to their own accuracy. Here, we explored whether sensory predictions based on internal physical models could be used to accurately calibrate visual cues to 3D surface slant. Human observers played a 3D kinematic game in which they adjusted the slant of a surface so that a moving ball would bounce off the surface and through a target hoop. In one group, the ball's bounce was manipulated so that the surface behaved as if it had a different slant to that signaled by visual cues. With experience of this altered bounce, observers recalibrated their perception of slant so that it was more consistent with the assumed laws of kinematics and physical behavior of the surface. In another group, making the ball spin in a way that could physically explain its altered bounce eliminated this pattern of recalibration. Importantly, both groups adjusted their behavior in the kinematic game in the same way, experienced the same set of slants, and were not presented with low-level cue conflicts that could drive the recalibration. We conclude that observers use predictive kinematic models to accurately calibrate visual cues to 3D properties of world. PMID:25080598
Loizu, J.; Hudson, S.; Bhattacharjee, A.; Helander, P.
2015-02-15
Using the recently developed multiregion, relaxed MHD (MRxMHD) theory, which bridges the gap between Taylor's relaxation theory and ideal MHD, we provide a thorough analytical and numerical proof of the formation of singular currents at rational surfaces in non-axisymmetric ideal MHD equilibria. These include the force-free singular current density represented by a Dirac δ-function, which presumably prevents the formation of islands, and the Pfirsch-Schlüter 1/x singular current, which arises as a result of finite pressure gradient. An analytical model based on linearized MRxMHD is derived that can accurately (1) describe the formation of magnetic islands at resonant rational surfaces, (2) retrieve the ideal MHD limit where magnetic islands are shielded, and (3) compute the subsequent formation of singular currents. The analytical results are benchmarked against numerical simulations carried out with a fully nonlinear implementation of MRxMHD.
NASA Astrophysics Data System (ADS)
Vishwanath, Ashvin; Senthil, T.
2013-01-01
We discuss physical properties of “integer” topological phases of bosons in D=3+1 dimensions, protected by internal symmetries like time reversal and/or charge conservation. These phases invoke interactions in a fundamental way but do not possess topological order; they are bosonic analogs of free-fermion topological insulators and superconductors. While a formal cohomology-based classification of such states was recently discovered, their physical properties remain mysterious. Here, we develop a field-theoretic description of several of these states and show that they possess unusual surface states, which, if gapped, must either break the underlying symmetry or develop topological order. In the latter case, symmetries are implemented in a way that is forbidden in a strictly two-dimensional theory. While these phases are the usual fate of the surface states, exotic gapless states can also be realized. For example, tuning parameters can naturally lead to a deconfined quantum critical point or, in other situations, to a fully symmetric vortex metal phase. We discuss cases where the topological phases are characterized by a quantized magnetoelectric response θ, which, somewhat surprisingly, is an odd multiple of 2π. Two different surface theories are shown to capture these phenomena: The first is a nonlinear sigma model with a topological term. The second invokes vortices on the surface that transform under a projective representation of the symmetry group. We identify a bulk-field theory consistent with these properties, which is a multicomponent background-field theory supplemented, crucially, with a topological term. We also provide bulk sigma-model field theories of these phases and discuss a possible topological phase characterized by the thermal analog of the magnetoelectric effect.
An optical profilometer for spatial characterization of three-dimensional surfaces
NASA Technical Reports Server (NTRS)
Kelly, W. L., IV; Burcher, E. E.; Skolaut, M. W., Jr.
1977-01-01
The design concept and system operation of an optical profilometer are discussed, and a preliminary evaluation of a breadboard system is presented to demonstrate the feasibility of the optical profilometer technique. Measurement results are presented for several test surfaces; and to illustrate a typical application, results are shown for a cleft palate cast used by dental surgeons. Finally, recommendations are made for future development of the optical profilometer technique for specific engineering or scientific applications.
Three-dimensional analysis of surface crack-Hertzian stress field interaction
NASA Technical Reports Server (NTRS)
Ballarini, R.; Hsu, Y.
1989-01-01
The results are presented of a stress intensity factor analysis of semicircular surface cracks in the inner raceway of an engine bearing. The loading consists of a moving spherical Hertzian contact load and an axial stress due to rotation and shrink fit. A 3-D linear elastic Boundary Element Method code was developed to perform the stress analysis. The element library includes linear and quadratic isoparametric surface elements. Singular quarter point elements were employed to capture the square root displacement variation and the inverse square root stress singularity along the crack front. The program also possesses the capability to separate the whole domain into two subregions. This procedure enables one to solve nonsymmetric fracture mechanics problems without having to separate the crack surfaces a priori. A wide range of configuration parameters was investigated. The ratio of crack depth to bearing thickness was varied from one-sixtieth to one-fifth for several different locations of the Hertzian load. The stress intensity factors for several crack inclinations were also investigated. The results demonstrate the efficiency and accuracy of the Boundary Element Method. Moreover, the results can provide the basis for crack growth calculations and fatigue life prediction.
Dagdeviren, Omur E; Schwendemann, Todd C; Mönig, Harry; Altman, Eric I
2012-01-01
Summary Noncontact atomic force microscopy (NC-AFM) is being increasingly used to measure the interaction force between an atomically sharp probe tip and surfaces of interest, as a function of the three spatial dimensions, with picometer and piconewton accuracy. Since the results of such measurements may be affected by piezo nonlinearities, thermal and electronic drift, tip asymmetries, and elastic deformation of the tip apex, these effects need to be considered during image interpretation. In this paper, we analyze their impact on the acquired data, compare different methods to record atomic-resolution surface force fields, and determine the approaches that suffer the least from the associated artifacts. The related discussion underscores the idea that since force fields recorded by using NC-AFM always reflect the properties of both the sample and the probe tip, efforts to reduce unwanted effects of the tip on recorded data are indispensable for the extraction of detailed information about the atomic-scale properties of the surface. PMID:23019560
Narr, Katherine L.; Thompson, Paul M.; Sharma, Tonmoy; Moussai, Jacob; Zoumalan, Chris; Rayman, Janice; Toga, Arthur W.
2008-01-01
Objective People with schizophrenia exhibit abnormalities in brain structure, often in the left hemisphere. Disturbed structural lateralization is controversial, however, and effects appear mediated by gender. The authors mapped differences between schizophrenic and normal subjects in gyral asymmetries, complexity, and variability across the entire cortex. Method Asymmetry and shape profiles for 25 schizophrenic patients (15 men) and 28 demographically similar normal subjects (15 men) were obtained for 38 gyral regions, including the sylvian fissure and temporal and postcentral gyri, by using magnetic resonance data and a novel surface-based mesh-modeling approach. Cortical complexity was examined for sex and diagnosis effects in lobar regions. Intragroup variability was quantified and visualized to assess regional group abnormalities at the cortical surface. Results The patients showed greater variability in frontal areas than the comparison subjects. They also had significant deviations in gyral complexity asymmetry in the superior frontal cortex. In temporoparietal regions, significant gyral asymmetries were present in both groups. Sex differences were apparent in superior temporal gyral measures, and cortical complexity in inferior frontal regions was significantly greater in men. Conclusions Cortical variability and complexity show regional abnormalities in the frontal cortex potentially specific to schizophrenia. The results indicate highly significant temporoparietal gyral asymmetries in both diagnostic groups, contrary to reports of less lateralization in schizophrenia. Substantially larger study groups are necessary to isolate smaller deviations in surface asymmetries, if present in schizophrenia, suggesting their diagnostic value is minimal. PMID:11156807
NASA Astrophysics Data System (ADS)
Williams, J.; Paige, D. A.; Vasavada, A. R.
2010-12-01
The Diviner Lunar Radiometer Experiment on NASA's Lunar Reconnaissance Orbiter has been mapping the global thermal state of the Moon since July of 2009. The instrument has acquired solar reflectance and thermal emission data in nine spectral channels spanning a wavelength range from 0.3 to 400 microns [1] revealing the extreme nature of the lunar thermal environment. Superposed on the large-scale trends due to latitude, time of day, and season, the surface temperature of the Moon can exhibit extreme spatial variations at length scales all the way down to that of the diurnal thermal skin depth (˜10 cm) due to the low thermal conductivity of the bulk of the regolith, the lack of an appreciable atmosphere, and the effects of slopes and shadowing [2]. Further, surface temperatures are highly sensitive to the thermophysical properties within the first few meters of the surface and thus spatial variations in density, thermal conductivity, heat capacity, albedo, and emissivity, will have an influence. This significantly complicates the interpretation of lunar thermal observations and thermal model results. To aid in our interpretation of Diviner data and model derived results, we are developing a 3-diminsional regolith model to better understand how variations both vertically and laterally of the thermophysical properties of the lunar regolith can affect Diviner observations. This extends previous 1-dimisional modeling efforts which included vertical layering [3] to now capture lateral variability in regolith properties which, in the lunar environment, can result in extreme thermal gradients over short length scales (10’s cm). The initial application of the model is to explore the sensitivity of the surface temperature throughout the diurnal cycle to rocks in the regolith. With no appreciable atmosphere to buffer surface temperatures, the nighttime environment is characterized by extreme cold with the sensible heat stored in the subsurface during the day being the only
NASA Astrophysics Data System (ADS)
Aryeh, F.
1982-01-01
Three interactive software systems dealing with the computerized definition, storage and handling of aircraft geometric shapes and entities in a multidisciplinary design environment are presented. The systems are operated in an interactive fashion via use of low cost graphic display terminals driven by a remote computer in a time sharing mode. GEODEF is a system for interactive definition of complex aircraft surfaces, GEOBASE is a system for interrogation and manipulation of a computerized aircraft geometry data base, and DOG is a 3-D detailed structural and mechanical part definition system.
A three dimensional radiative transfer method for optical remote sensing of vegetated land surfaces
NASA Technical Reports Server (NTRS)
Asrar, Ghassem; Myneni, Ranga B.; Choudhury, Bhaskar J.
1991-01-01
In the application of remote sensing at optical wavelengths to vegetated surfaces from satellite borne high resolution instruments, an understanding of the various physical mechanisms that contribute to the measured signal is important. A numerical method of solving the radiative transfer equation in three dimensions is reported. The reliability of coding and accuracy of the algorithm are evaluated by benchmarching. Parametrization of the methods and results of a simulation are presented. The method is tested with experimental data of canopy bidirectional reflectance factors. The effect of spatial heterogeneity on the relationship between the simple ratio and normalized vrs absorbed Photosynthetically Active Radiation (PAR) is discussed.
A Three-Dimensional View of Titan's Surface Features from Cassini RADAR Stereogrammetry
NASA Astrophysics Data System (ADS)
Kirk, R. L.; Howington-Kraus, E.; Redding, B. L.; Becker, T. L.; Lee, E. M.; Stiles, B. W.; Hensley, S.; Hayes, A.; Lopes, R. M.; Lorenz, R. D.; Mitchell, K. L.; Radebaugh, J.; Paganelli, F.; Soderblom, L. A.; Stofan, E. R.; Wood, C. A.; Wall, S. D.; Cassini RADAR Team
2008-12-01
As of the end of its four-year Prime Mission, Cassini has obtained 300-1500 m resolution synthetic aperture radar images of the surface of Titan during 19 flybys. The elongated image swaths overlap extensively, and ~2% of the surface has now been imaged two or more times. The majority of image pairs have different viewing directions, and thus contain stereo parallax that encodes information about Titan's surface relief over distances of ~1 km and greater. As we have previously reported, the first step toward extracting quantitative topographic information was the development of rigorous "sensor models" that allowed the stereo systems previously used at the USGS and JPL to map Venus with Magellan images to be used for Titan mapping. The second major step toward extensive topomapping of Titan has been the reprocessing of the RADAR images based on an improved model of the satellite's rotation. Whereas the original images (except for a few pairs obtained at similar orbital phase, some of which we have mapped previously) were offset by as much as 30 km, the new versions align much better. The remaining misalignments, typically <1 km, can be removed by a least-squares adjustment of the spacecraft trajectories before mapping, which also ensures that the stereo digital topographic models (DTMs) are made consistent with altimetry and SAR topography profiles. The useful stereo coverage now available includes a much larger portion of Titan's north polar lake country than we previously presented, a continuous traverse of high resolution data from the lakes to mid-southern latitudes, and widely distributed smaller areas. A remaining challenge is that many pairs of images are illuminated from opposite sides or from near-perpendicular directions, which can make image matching more difficult. We find that the high-contrast polarizing display of the stereo workstation at USGS provides a much clearer view of these unfavorably illuminated pairs than (for example) anaglyphs, and lets
NASA Astrophysics Data System (ADS)
Taylor, N. J.; Dueker, K. G.; Riebe, C. S.; Chen, P.; Flinchum, B. A.; Holbrook, W. S.
2015-12-01
In mountain landscapes, vegetation is tightly coupled to elevation through orographic effects on temperature and precipitation. However, at any given elevation, vegetation can vary markedly due to non-climatic factors such as lithology. For example, tree-canopy cover correlates strongly with bedrock composition in the Sierra Nevada, California, via mechanisms that remain poorly understood. We are exploring the hypothesis that vegetation varies across bedrock types in the Sierra Nevada due to differences in near-surface fracture density that influence the availability of water for plants. Our approach uses data collected from autonomous seismic nodes that record seismic energy generated by ambient sources such as wind, rivers, and road traffic. By deploying the nodes across the landscape in arrays spanning 200 m on a side, we can obtain a three-dimensional image of spatial variations in near-surface weathering. Data presented here will be derived from arrays deployed for 3 days each spanning an area of 0.04 km2 at each of three sites underlain by Sierra Nevada granites and granodiorites. To isolate the effects of lithology on vegetation, we chose sites that span a range of forest cover and mafic-mineral content but have similar microclimate (i.e., with similar aspect and elevation). Our data will provide a three-dimensional model of P- and S-wave velocity structure, which we can invert using a Hertz-Mindlin porosity model to constrain the thickness and degree of fracturing and thus the subsurface water-holding potential for plants. We will explore the hypothesis that the densest vegetation occurs within bedrock with the densest fracturing, due to enhanced availability of water in the near surface. We will present a comparison of our results from the Sierra Nevada and results from similar experiments at the Snowy Range and Blair Wallis field sites of the Wyoming Center for Environmental Hydrology and Geophysics.
2015-01-01
Porous graphitic carbon is essential for many applications such as energy storage devices, catalysts, and sorbents. However, current graphitic carbons are limited by low conductivity, low surface area, and ineffective pore structure. Here we report a scalable synthesis of porous graphitic carbons using a conjugated polymeric molecular framework as precursor. The multivalent cross-linker and rigid conjugated framework help to maintain micro- and mesoporous structures, while promoting graphitization during carbonization and chemical activation. The above unique design results in a class of highly graphitic carbons at temperature as low as 800 °C with record-high surface area (4073 m2 g–1), large pore volume (2.26 cm–3), and hierarchical pore architecture. Such carbons simultaneously exhibit electrical conductivity >3 times more than activated carbons, very high electrochemical activity at high mass loading, and high stability, as demonstrated by supercapacitors and lithium–sulfur batteries with excellent performance. Moreover, the synthesis can be readily tuned to make a broad range of graphitic carbons with desired structures and compositions for many applications. PMID:27162953
Three-Dimensional Surface Profile Intensity Correction for Spatially-Modulated Imaging
Gioux, Sylvain; Mazhar, Amaan; Cuccia, David J.; Durkin, Anthony J.; Tromberg, Bruce J.; Frangioni, John V.
2009-01-01
We describe a non-contact profile correction technique for quantitative, wide-field optical measurement of tissue absorption (µa) and reduced scattering (µs’) coefficients, based on geometric correction of the sample’s Lambertian (diffuse) reflectance intensity. Since the projection of structured light onto an object is the basis for both phase-shifting profilometry and modulated imaging, we were able to develop a single instrument capable of performing both techniques. In so doing, the surface of the 3-dimensional object could be acquired and used to extract the object’s optical properties. The optical properties of flat polydimethylsiloxane (silicone) phantoms with homogenous tissue-like optical properties were extracted, with and without profilometry correction, after vertical translation and tilting of the phantoms at various angles. Objects having a complex shape, including a hemispheric silicone phantom and human fingers, were acquired and similarly processed, with vascular constriction of a finger being readily detectable through changes in its optical properties. Using profilometry correction, the accuracy of extracted absorption and reduced scattering coefficients improved from 2- to 10-fold for surfaces having height variations as much as 3 cm and tilt angles as high as 40°. These data lay the foundation for employing structured light for quantitative imaging during surgery. PMID:19566337
Three-dimensional manipulation of single cells using surface acoustic waves
Guo, Feng; Mao, Zhangming; Chen, Yuchao; Xie, Zhiwei; Lata, James P.; Li, Peng; Ren, Liqiang; Liu, Jiayang; Yang, Jian; Dao, Ming; Suresh, Subra; Huang, Tony Jun
2016-01-01
The ability of surface acoustic waves to trap and manipulate micrometer-scale particles and biological cells has led to many applications involving “acoustic tweezers” in biology, chemistry, engineering, and medicine. Here, we present 3D acoustic tweezers, which use surface acoustic waves to create 3D trapping nodes for the capture and manipulation of microparticles and cells along three mutually orthogonal axes. In this method, we use standing-wave phase shifts to move particles or cells in-plane, whereas the amplitude of acoustic vibrations is used to control particle motion along an orthogonal plane. We demonstrate, through controlled experiments guided by simulations, how acoustic vibrations result in micromanipulations in a microfluidic chamber by invoking physical principles that underlie the formation and regulation of complex, volumetric trapping nodes of particles and biological cells. We further show how 3D acoustic tweezers can be used to pick up, translate, and print single cells and cell assemblies to create 2D and 3D structures in a precise, noninvasive, label-free, and contact-free manner. PMID:26811444
Three-dimensional manipulation of single cells using surface acoustic waves.
Guo, Feng; Mao, Zhangming; Chen, Yuchao; Xie, Zhiwei; Lata, James P; Li, Peng; Ren, Liqiang; Liu, Jiayang; Yang, Jian; Dao, Ming; Suresh, Subra; Huang, Tony Jun
2016-02-01
The ability of surface acoustic waves to trap and manipulate micrometer-scale particles and biological cells has led to many applications involving "acoustic tweezers" in biology, chemistry, engineering, and medicine. Here, we present 3D acoustic tweezers, which use surface acoustic waves to create 3D trapping nodes for the capture and manipulation of microparticles and cells along three mutually orthogonal axes. In this method, we use standing-wave phase shifts to move particles or cells in-plane, whereas the amplitude of acoustic vibrations is used to control particle motion along an orthogonal plane. We demonstrate, through controlled experiments guided by simulations, how acoustic vibrations result in micromanipulations in a microfluidic chamber by invoking physical principles that underlie the formation and regulation of complex, volumetric trapping nodes of particles and biological cells. We further show how 3D acoustic tweezers can be used to pick up, translate, and print single cells and cell assemblies to create 2D and 3D structures in a precise, noninvasive, label-free, and contact-free manner. PMID:26811444
To, John W F; Chen, Zheng; Yao, Hongbin; He, Jiajun; Kim, Kwanpyo; Chou, Ho-Hsiu; Pan, Lijia; Wilcox, Jennifer; Cui, Yi; Bao, Zhenan
2015-05-27
Porous graphitic carbon is essential for many applications such as energy storage devices, catalysts, and sorbents. However, current graphitic carbons are limited by low conductivity, low surface area, and ineffective pore structure. Here we report a scalable synthesis of porous graphitic carbons using a conjugated polymeric molecular framework as precursor. The multivalent cross-linker and rigid conjugated framework help to maintain micro- and mesoporous structures, while promoting graphitization during carbonization and chemical activation. The above unique design results in a class of highly graphitic carbons at temperature as low as 800 °C with record-high surface area (4073 m(2) g(-1)), large pore volume (2.26 cm(-3)), and hierarchical pore architecture. Such carbons simultaneously exhibit electrical conductivity >3 times more than activated carbons, very high electrochemical activity at high mass loading, and high stability, as demonstrated by supercapacitors and lithium-sulfur batteries with excellent performance. Moreover, the synthesis can be readily tuned to make a broad range of graphitic carbons with desired structures and compositions for many applications. PMID:27162953
Three dimensional modeling and inversion of Borehole-surface Electrical Resistivity Data
NASA Astrophysics Data System (ADS)
Zhang, Y.; Liu, D.; Liu, Y.; Qin, M.
2013-12-01
After a long time of exploration, many oil fields have stepped into the high water-cut period. It is sorely needed to determining the oil-water distribution and water flooding front. Borehole-surface electrical resistivity tomography (BSERT) system is a low-cost measurement with wide measuring scope and small influence on the reservoir. So it is gaining more and more application in detecting water flooding areas and evaluating residual oil distribution in oil fields. In BSERT system, current is connected with the steel casing of the observation well. The current flows along the long casing and transmits to the surface through inhomogeneous layers. Then received electric potential difference data on the surface can be used to inverse the deep subsurface resistivity distribution. This study presents the 3D modeling and inversion method of electrical resistivity data. In an extensive literature, the steel casing is treated as a transmission line current source with infinite small radius and constant current density. However, in practical multi-layered formations with different resistivity, the current density along the casing is not constant. In this study, the steel casing is modeled by a 2.5e-7 ohm-m physical volume that the casing occupies in the finite element mesh. Radius of the casing can be set to a little bigger than the true radius, and this helps reduce the element number and computation time. The current supply point is set on the center of the top surface of the physical volume. The homogeneous formation modeling result shows the same precision as the transmission line current source model. The multi-layered formation modeling result shows that the current density along the casing is high in the low-resistivity layer, and low in the high-resistivity layer. These results are more reasonable. Moreover, the deviated and horizontal well can be simulated as simple as the vertical well using this modeling method. Based on this forward modeling method, the
Nadeem, Danish; Smith, Carol-Anne; Dalby, Matthew J; Meek, R M Dominic; Lin, Sien; Li, Gang; Su, Bo
2015-01-01
Surface topography is known to influence stem cells and has been widely used as physical stimuli to modulate cellular behaviour including adhesion, proliferation and differentiation on 2D surfaces. Integration of well-defined surface topography into three-dimensional (3D) scaffolds for tissue engineering would be useful to direct the cell fate for intended applications. Technical challenges are remaining as how to fabricate such 3D scaffolds with controlled surface topography from a range of biodegradable and biocompatible materials. In this paper, a novel fabrication process using computer numerically controlled machining and lamination is reported to make 3D calcium phosphate/gelatin composite scaffolds with integrated surface micropatterns that are introduced by embossing prior to machining. Geometric analysis shows that this method is versatile and can be used to make a wide range of lattices with porosities that meet the basic requirements for bone tissue engineering. Both in vitro and in vivo studies show that micropatterned composite scaffolds with surfaces comprising 40 μm pits and 50 μm grooves were optimal for improved osteogenesis. The results have demonstrated the potential of a novel fabrication process for producing cell-instructive scaffolds with designed surface topographies to induce specific tissue regeneration. PMID:25562325
Suzuki, Kazuhiro; Oyabu, Noriaki; Matsushige, Kazumi; Yamada, Hirofumi; Kobayashi, Kei
2014-02-07
Surface charges on nanoscale structures in liquids, such as biomolecules and nano-micelles, play an essentially important role in their structural stability as well as their chemical activities. These structures interact with each other through electric double layers (EDLs) formed by the counter ions in electrolyte solution. Although static-mode atomic force microscopy (AFM) including colloidal-probe AFM is a powerful technique for surface charge density measurements and EDL analysis on a submicron scale in liquids, precise surface charge density analysis with single-nanometer resolution has not been made because of its limitation of the resolution and the detection sensitivity. Here we demonstrate molecular-scale surface charge measurements of self-assembled micellar structures, molecular hemicylinders of sodium dodecyl sulfate (SDS), by three-dimensional (3D) force mapping based on frequency modulation AFM. The SDS hemicylindrical structures with a diameter of 4.8 nm on a graphite surface were clearly imaged. We have succeeded in visualizing 3D EDL forces on the SDS hemicylinder surfaces and obtaining the molecular-scale charge density for the first time. The results showed that the surface charge on the trench regions between the hemicylinders was much smaller than that on the hemicylinder tops. The method can be applied to a wide variety of local charge distribution studies, such as spatial charge variation on a single protein molecule.
NASA Astrophysics Data System (ADS)
Fujii, Toru; Yamaguchi, Masataka; Suzuki, Masatoshi
1995-03-01
The scanning tunneling microscope (STM) has been known for its high lateral resolution, but its unreliable vertical accuracy has prevented it from being widely used as a profiler for roughness and step height measurements. An STM equipped with an optical interferometer to calibrate STM tip feedback controlled motion in the Z direction along with interferometers for monitoring X and Y raster scanning has been developed. The resolution of the interferometer was 0.12 nm rms. Maximum line scanning distance is 250 μm and the motion in this direction is secured by a parallel spring mechanism. Step height and pitch measurements on a surface topography standard agree in nanometer scale with the certified value of the standard. The result of high accuracy roughness measurement with the STM supports the common observation that STM measurement gives larger roughness than interferometric measurement.
Computed myography: three-dimensional reconstruction of motor functions from surface EMG data
NASA Astrophysics Data System (ADS)
van den Doel, Kees; Ascher, Uri M.; Pai, Dinesh K.
2008-12-01
We describe a methodology called computed myography to qualitatively and quantitatively determine the activation level of individual muscles by voltage measurements from an array of voltage sensors on the skin surface. A finite element model for electrostatics simulation is constructed from morphometric data. For the inverse problem, we utilize a generalized Tikhonov regularization. This imposes smoothness on the reconstructed sources inside the muscles and suppresses sources outside the muscles using a penalty term. Results from experiments with simulated and human data are presented for activation reconstructions of three muscles in the upper arm (biceps brachii, bracialis and triceps). This approach potentially offers a new clinical tool to sensitively assess muscle function in patients suffering from neurological disorders (e.g., spinal cord injury), and could more accurately guide advances in the evaluation of specific rehabilitation training regimens.
Azeem Khan, Waqar; Khan, Masood; Malik, Rabia
2014-01-01
This article addresses the steady three-dimensional flow of an Oldroyd-B nanofluid over a bidirectional stretching surface with heat generation/absorption effects. Suitable similarity transformations are employed to reduce the governing partial differential equations into coupled nonlinear ordinary differential equations. These nonlinear ordinary differential equations are then solved analytically by using the homotpy analysis method (HAM). Graphically results are presented and discussed for various parameters, namely, Deborah numbers and , heat generation/absorption parameter Prandtl parameter , Brownian motion parameters, thermophoresis parameter and Lewis number . We have seen that the increasing values of the Brownian motion parameter and thermophoresis parameter leads to an increase in the temperature field and thermal boundary layer thickness while the opposite behavior is observed for concentration field and concentration boundary layer thickness. To see the validity of the present work, the numerical results are compared with the analytical solutions obtained by Homotopy analysis method and noted an excellent agreement for the limiting cases. PMID:25170945
NASA Astrophysics Data System (ADS)
Zeng, Zhuohuan; Fu, Yanjun; Li, Biao; Chai, Minggang
2016-08-01
Binary pattern defocused projection method can overcome the nonlinear gamma of the projector, as well as filter high harmonics and high-frequency noise. However, high-accuracy three-dimensional (3-D) shape measurement of complex surface using it still remains a challenge. Therefore, a novel Gray code plus phase-shifting method based on defocusing is proposed to solve the problem. The edges of Gray code patterns become blurred owing to defocus, which makes the recovery of accurate Gray code patterns difficult. To solve this problem, the positive and inverse Gray code patterns are projected to obtain threshold values, which are used to achieve the binarization of Gray code patterns. This method is robust and suitable for different defocus levels. Compared with the traditional Gray code plus phase-shifting method, the experimental results prove the effectiveness and feasibility of the proposed method.
Three-dimensional flow separation over a surface-mounted hemisphere in pulsatile flow
NASA Astrophysics Data System (ADS)
Carr, Ian A.; Plesniak, Michael W.
2016-01-01
Flow separation over a surface-mounted obstacle is prevalent in numerous applications. Previous studies of 3D separation around protuberances have been limited to steady flow. In biological and geophysical flows, pulsatile conditions are frequently encountered, yet this situation has not been extensively studied. Primarily motivated by our previous studies of the flow patterns observed in various human vocal fold pathologies such as polyps, our research aimed to fill this gap in the knowledge concerning unsteady 3D flow separation. This is achieved by characterizing velocity fields surrounding the obstacle, focused primarily on the vortical flow structures and dynamics that occur around a hemispheroid in pulsatile flow. As part of this study, two-dimensional, instantaneous and phase-averaged particle image velocimetry data in both steady and pulsatile flows are presented and compared. Coherent vortical flow structures have been identified by their swirling strength. This analysis revealed flow structures with dynamics dependent on the pulsatile forcing function. A mechanism to explain the formation and observed dynamics of these flow structures based on the self-induced velocity of vortex rings interacting with the unsteady flow is proposed.
Shao, J. M.; Yao, J. D.; Yang, G. W.
2015-05-21
We describe a theoretical study of the terahertz (THz) radiation field-induced dc transport response of the surface state of a 3D topological insulator that has been subjected to a perpendicular magnetic field. Using the Landau–Floquet state and linear response theory, we obtain the photoconductivity characteristics for various types of polarized THz field. The longitudinal photoconductivity shows a clear oscillatory dependence on ω/ω{sub B}, where ω{sub B}=v{sub F}√(2eB/ℏ). This oscillation occurs because of the oscillatory structure of the Landau density of states and occurs in agreement with the photon-assisted transitions between the different Landau levels. The THz field's polarization has a major influence on the photoconductivity. A linear transverse polarization will lead to the most obvious oscillation, while the circular polarization is next to it, but the longitudinal polarization has no influence. We also discuss the broadening effect on the impurity potential and its influence. The findings with regard to the interactions between topological insulators and THz fields actually open a path toward the development of THz device applications of topological insulators.
Modeling Three-Dimensional Upper Mantle Seismic Anisotropy with Higher Mode Surface Waves
NASA Astrophysics Data System (ADS)
Yuan, Kaiqing
This dissertation presents a new 3-D global upper mantle model of elastic anisotropy obtained from surface wave seismic tomography. This research contributes to our understanding of deep Earth structure. The two main results are the following: (1) Our work unravels the presence of azimuthal seismic anisotropy in the mantle transition zone, to greater depths than previously found, thereby challenging common views of mantle deformation mechanisms. It also reveals a striking correlation between changes in seismic anisotropy where upper mantle phase transitions occur, which provides new constraints on the style of mantle convection; (2) We confirm the dominantly thermal nature of the oceanic lithosphere-asthenosphere boundary (LAB), and show that the Gutenberg discontinuity associated with vertical changes in azimuthal anisotropy inside the lithosphere, implying that this interface is not equivalent to the LAB, contrary to what is commonly assumed. The origin of the Gutenberg discontinuity is a result of frozen-in lithospheric structures, regional compositional variations of the mantle, or dynamically perturbed LAB.
Ahmed, Ijaz; Liu, Hsing-Yin; Mamiya, Ping C; Ponery, Abdul S; Babu, Ashwin N; Weik, Thom; Schindler, Melvin; Meiners, Sally
2006-03-15
Current methods to promote growth of cultured neurons use two-dimensional (2D) glass or polystyrene surfaces coated with a charged molecule (e.g. poly-L-lysine (PLL)) or an isolated extracellular matrix (ECM) protein (e.g. laminin-1). However, these 2D surfaces represent a poor topological approximation of the three-dimensional (3D) architecture of the assembled ECM that regulates neuronal growth in vivo. Here we report on the development of a new 3D synthetic nanofibrillar surface for the culture of neurons. This nanofibrillar surface is composed of polyamide nanofibers whose organization mimics the porosity and geometry of the ECM. Neuronal adhesion and neurite outgrowth from cerebellar granule, cerebral cortical, hippocampal, motor, and dorsal root ganglion neurons were similar on nanofibers and PLL-coated glass coverslips; however, neurite generation was increased. Moreover, covalent modification of the nanofibers with neuroactive peptides derived from human tenascin-C significantly enhanced the ability of the nanofibers to facilitate neuronal attachment, neurite generation, and neurite extension in vitro. Hence the 3D nanofibrillar surface provides a physically and chemically stabile cell culture surface for neurons and, potentially, an exciting new opportunity for the development of peptide-modified matrices for use in strategies designed to encourage axonal regrowth following central nervous system injury. PMID:16345089
NASA Astrophysics Data System (ADS)
Carroll, T. A.; Kopf, M.
2008-04-01
Aims:The thermodynamic and magnetic field structure of the solar photosphere is analyzed by means of a novel 3-dimensional spectropolarimetric inversion and reconstruction technique. Methods: On the basis of high-resolution, mixed-polarity magnetoconvection simulations, we used an artificial neural network (ANN) model to approximate the nonlinear inverse mapping between synthesized Stokes spectra and the underlying stratification of atmospheric parameters like temperature, line-of-sight (LOS) velocity and LOS magnetic field. This approach not only allows us to incorporate more reliable physics into the inversion process, it also enables the inversion on an absolute geometrical height scale, which allows the subsequent combination of individual line-of-sight stratifications to obtain a complete 3-dimensional reconstruction (tomography) of the observed area. Results: The magnetoconvection simulation data, as well as the ANN inversion, have been properly processed to be applicable to spectropolarimetric observations from the Hinode satellite. For the first time, we show 3-dimensional tomographic reconstructions (temperature, LOS velocity, and LOS magnetic field) of a quiet sun region observed by Hinode. The reconstructed area covers a field of approximately 12 000 × 12 000 km and a height range of 510 km in the photosphere. An enormous variety of small and large scale structures can be identified in the 3-D reconstructions. The low-flux region (B_mag = 20 G) we analyzed exhibits a number of tube-like magnetic structures with field strengths of several hundred Gauss. Most of these structures rapidly loose their strength with height and only a few larger structures can retain a higher field strength to the upper layers of the photosphere.
Koo, Ja Eun; Kim, Jong Hoon; Lim, Young-Suk
2010-09-01
Purpose: To evaluate the effects of transarterial chemoembolization (TACE) and three-dimensional conformal radiotherapy (CRT) in patients with hepatocellular carcinoma (HCC) and inferior vena cava tumor thrombus (IVCTT). Methods and Materials: A total of 42 consecutive patients who underwent TACE and CRT (TACE+CRT group) for the treatment of HCC with IVCTT were prospectively enrolled from July 2004 to October 2006. As historical controls, 29 HCC patients with IVCTT who received TACE alone (TACE group) between July 2003 and June 2004 were included. CRT was designed to target only the IVCTT and to deliver a median total dose of 45 Gy (range, 28-50 Gy). Results: Most baseline characteristics of the two groups were similar (p > 0.05). The response and progression-free rates of IVCTT were significantly higher in the TACE+CRT group than in the TACE group (42.9% and 71.4% vs. 13.8% and 37.9%, respectively; p < 0.01 for both rates). Overall, patient survival was significantly higher in the TACE+CRT group than in the TACE group (p < 0.01), with a median survival time of 11.7 months and 4.7 months, respectively. Treatment with TACE+CRT (hazard ratio [HR] = 0.38; 95% confidence interval [CI], 0.20-0.71), progression of IVCTT (HR = 4.05; 95% CI, 2.00-8.21), Child-Pugh class B (HR = 3.44; 95% CI, 1.79-6.61), and portal vein invasion (HR = 2.31; 95% CI, 1.19-4.50) were identified as independent predictors of mortality by multivariable analysis. Conclusions: The combination of TACE and CRT is more effective in the control of IVCTT associated with HCC and improves patient survival compared with TACE alone.
Munroe, J.S.; Doolittle, J.A.; Kanevskiy, M.Z.; Hinkel, Kenneth M.; Nelson, F.E.; Jones, Benjamin M.; Shur, Y.; Kimble, J.M.
2007-01-01
Three-dimensional ground-penetrating radar (3D GPR) was used to investigate the subsurface structure of ice-wedge polygons and other features of the frozen active layer and near-surface permafrost near Barrow, Alaska. Surveys were conducted at three sites located on landscapes of different geomorphic age. At each site, sediment cores were collected and characterised to aid interpretation of GPR data. At two sites, 3D GPR was able to delineate subsurface ice-wedge networks with high fidelity. Three-dimensional GPR data also revealed a fundamental difference in ice-wedge morphology between these two sites that is consistent with differences in landscape age. At a third site, the combination of two-dimensional and 3D GPR revealed the location of an active frost boil with ataxitic cryostructure. When supplemented by analysis of soil cores, 3D GPR offers considerable potential for imaging, interpreting and 3D mapping of near-surface soil and ice structures in permafrost environments.
Exotic quantum critical point on the surface of three-dimensional topological insulator
NASA Astrophysics Data System (ADS)
Bi, Zhen; You, Yi-Zhuang; Xu, Cenke
2016-07-01
In the last few years a lot of exotic and anomalous topological phases were constructed by proliferating the vortexlike topological defects on the surface of the 3 d topological insulator (TI) [Fidkowski et al., Phys. Rev. X 3, 041016 (2013), 10.1103/PhysRevX.3.041016; Chen et al., Phys. Rev. B 89, 165132 (2014), 10.1103/PhysRevB.89.165132; Bonderson et al., J. Stat. Mech. (2013) P09016, 10.1088/1742-5468/2013/09/P09016; Wang et al., Phys. Rev. B 88, 115137 (2013), 10.1103/PhysRevB.88.115137; Metlitski et al., Phys. Rev. B 92, 125111 (2015), 10.1103/PhysRevB.92.125111]. In this work, rather than considering topological phases at the boundary, we will study quantum critical points driven by vortexlike topological defects. In general, we will discuss a (2 +1 )d quantum phase transition described by the following field theory: L =ψ ¯γμ(∂μ-i aμ) ψ +| (∂μ-i k aμ) ϕ| 2+r|ϕ | 2+g |ϕ| 4 , with tuning parameter r , arbitrary integer k , Dirac fermion ψ , and complex scalar bosonic field ϕ , which both couple to the same (2 +1 )d dynamical noncompact U(1) gauge field aμ. The physical meaning of these quantities/fields will be explained in the text. Making use of the new duality formalism developed in [Metlitski et al., Phys. Rev. B 93, 245151 (2016), 10.1103/PhysRevB.93.245151; Wang et al., Phys. Rev. X 5, 041031 (2015), 10.1103/PhysRevX.5.041031; Wang et al., Phys. Rev. B 93, 085110 (2016), 10.1103/PhysRevB.93.085110; D. T. Son, Phys. Rev. X 5, 031027 (2015), 10.1103/PhysRevX.5.031027], we demonstrate that this quantum critical point has a quasi-self-dual nature. And at this quantum critical point, various universal quantities such as the electrical conductivity and scaling dimension of gauge-invariant operators, can be calculated systematically through a 1 /k2 expansion, based on the observation that the limit k →+∞ corresponds to an ordinary 3 d X Y transition.
Zhao, Jing; Sun, Mentao; Liu, Zhe; Quan, Baogang; Gu, Changzhi; Li, Junjie
2015-01-01
Three dimensional (3D) plasmonic nanostructure is perfect for the surface-enhanced Raman scattering (SERS) and also very suitable for surface catalytic reaction, but how to design and fabricate is still a robust task. Here, we show a 3D plasmonic nanohybrid of vertical graphene-nanosheet sandwiched by Ag-nanoparticles on the silicon nanocone array substrate for enhanced surface catalytic reaction. By SERS detection, we find that this hierarchical nanohybrid structure is highly efficient in the enhancement of catalytic reaction, even at a very low concentration of 10−11 M, which is far better than previous reports by four orders of magnitude. A strong electric field enhancement produced in the 3D framework nanohybrids of graphene nanosheet/Ag-nanoparticles is responsible for this great enhancement of catalytic reaction, due to larger electron collective oscillation in the composite system. Especially the oxygen adsorbed on the graphene and Ag nanoparticles can be excited to triplet excited states, and the electrons on the graphene and the nanoparticles can be effectively transferred to the oxygen, which plays very important role in molecular catalytic reactions. Our results demonstrate the contribution of graphene in plasmon-driven catalytic reactions, revealing a co-driven reaction process.This excellent SERS substrate can be used for future plasmon and graphene co-catalytic surface catalytic reactions, graphene-based surface plasmon sensors and so on. PMID:26522142
Boshkovikj, Veselin; Fluke, Christopher J.; Crawford, Russell J.; Ivanova, Elena P.
2014-01-01
There has been a growing interest in understanding the ways in which bacteria interact with nano-structured surfaces. As a result, there is a need for innovative approaches to enable researchers to visualize the biological processes taking place, despite the fact that it is not possible to directly observe these processes. We present a novel approach for the three-dimensional visualization of bacterial interactions with nano-structured surfaces using the software package Autodesk Maya. Our approach comprises a semi-automated stage, where actual surface topographic parameters, obtained using an atomic force microscope, are imported into Maya via a custom Python script, followed by a ‘creative stage', where the bacterial cells and their interactions with the surfaces are visualized using available experimental data. The ‘Dynamics' and ‘nDynamics' capabilities of the Maya software allowed the construction and visualization of plausible interaction scenarios. This capability provides a practical aid to knowledge discovery, assists in the dissemination of research results, and provides an opportunity for an improved public understanding. We validated our approach by graphically depicting the interactions between the two bacteria being used for modeling purposes, Staphylococcus aureus and Pseudomonas aeruginosa, with different titanium substrate surfaces that are routinely used in the production of biomedical devices. PMID:24577105
NASA Astrophysics Data System (ADS)
Zhao, Jing; Sun, Mentao; Liu, Zhe; Quan, Baogang; Gu, Changzhi; Li, Junjie
2015-11-01
Three dimensional (3D) plasmonic nanostructure is perfect for the surface-enhanced Raman scattering (SERS) and also very suitable for surface catalytic reaction, but how to design and fabricate is still a robust task. Here, we show a 3D plasmonic nanohybrid of vertical graphene-nanosheet sandwiched by Ag-nanoparticles on the silicon nanocone array substrate for enhanced surface catalytic reaction. By SERS detection, we find that this hierarchical nanohybrid structure is highly efficient in the enhancement of catalytic reaction, even at a very low concentration of 10-11 M, which is far better than previous reports by four orders of magnitude. A strong electric field enhancement produced in the 3D framework nanohybrids of graphene nanosheet/Ag-nanoparticles is responsible for this great enhancement of catalytic reaction, due to larger electron collective oscillation in the composite system. Especially the oxygen adsorbed on the graphene and Ag nanoparticles can be excited to triplet excited states, and the electrons on the graphene and the nanoparticles can be effectively transferred to the oxygen, which plays very important role in molecular catalytic reactions. Our results demonstrate the contribution of graphene in plasmon-driven catalytic reactions, revealing a co-driven reaction process.This excellent SERS substrate can be used for future plasmon and graphene co-catalytic surface catalytic reactions, graphene-based surface plasmon sensors and so on.
Boshkovikj, Veselin; Fluke, Christopher J; Crawford, Russell J; Ivanova, Elena P
2014-01-01
There has been a growing interest in understanding the ways in which bacteria interact with nano-structured surfaces. As a result, there is a need for innovative approaches to enable researchers to visualize the biological processes taking place, despite the fact that it is not possible to directly observe these processes. We present a novel approach for the three-dimensional visualization of bacterial interactions with nano-structured surfaces using the software package Autodesk Maya. Our approach comprises a semi-automated stage, where actual surface topographic parameters, obtained using an atomic force microscope, are imported into Maya via a custom Python script, followed by a 'creative stage', where the bacterial cells and their interactions with the surfaces are visualized using available experimental data. The 'Dynamics' and 'nDynamics' capabilities of the Maya software allowed the construction and visualization of plausible interaction scenarios. This capability provides a practical aid to knowledge discovery, assists in the dissemination of research results, and provides an opportunity for an improved public understanding. We validated our approach by graphically depicting the interactions between the two bacteria being used for modeling purposes, Staphylococcus aureus and Pseudomonas aeruginosa, with different titanium substrate surfaces that are routinely used in the production of biomedical devices. PMID:24577105
NASA Astrophysics Data System (ADS)
Marutschke, Christoph; Walters, Deron; Cleveland, Jason; Hermes, Ilka; Bechstein, Ralf; Kühnle, Angelika
2014-08-01
Calcite, the most stable modification of calcium carbonate, is a major mineral in nature. It is, therefore, highly relevant in a broad range of fields such as biomineralization, sea water desalination and oil production. Knowledge of the surface structure and reactivity of the most stable cleavage plane, calcite (10.4), is pivotal for understanding the role of calcite in these diverse areas. Given the fact that most biological processes and technical applications take place in an aqueous environment, perhaps the most basic—yet decisive—question addresses the interaction of water molecules with the calcite (10.4) surface. In this work, amplitude modulation atomic force microscopy is used for three-dimensional (3D) mapping of the surface structure and the hydration layers above the surface. An easy-to-use scanning protocol is implemented for collecting reliable 3D data. We carefully discuss a comprehensible criterion for identifying the solid-liquid interface within our data. In our data three hydration layers form a characteristic pattern that is commensurate with the underlying calcite surface.
Marutschke, Christoph; Walters, Deron; Walters, Deron; Hermes, Ilka; Bechstein, Ralf; Kühnle, Angelika
2014-08-22
Calcite, the most stable modification of calcium carbonate, is a major mineral in nature. It is, therefore, highly relevant in a broad range of fields such as biomineralization, sea water desalination and oil production. Knowledge of the surface structure and reactivity of the most stable cleavage plane, calcite (10.4), is pivotal for understanding the role of calcite in these diverse areas. Given the fact that most biological processes and technical applications take place in an aqueous environment, perhaps the most basic - yet decisive - question addresses the interaction of water molecules with the calcite (10.4) surface. In this work, amplitude modulation atomic force microscopy is used for three-dimensional (3D) mapping of the surface structure and the hydration layers above the surface. An easy-to-use scanning protocol is implemented for collecting reliable 3D data. We carefully discuss a comprehensible criterion for identifying the solid-liquid interface within our data. In our data three hydration layers form a characteristic pattern that is commensurate with the underlying calcite surface. PMID:25074402
ERIC Educational Resources Information Center
Kooloos, Jan G. M.; Vorstenbosch, Marc A. T. M.
2013-01-01
A teaching tool that facilitates student understanding of a three-dimensional (3D) integration of dermatomes with peripheral cutaneous nerve field distributions is described. This model is inspired by the confusion in novice learners between dermatome maps and nerve field distribution maps. This confusion leads to the misconception that these two…
Blevins, Erin L; Lauder, George V
2012-09-15
Rajiform locomotion in fishes is dominated by distinctive undulations of expanded pectoral fins. Unlike other fishes, which typically interact with the fluid environment via multiple fins, undulating rays modulate a single control surface, the pectoral disc, to perform pelagic locomotion, maneuvering and other behaviors. Complex deformations of the broad, flexible pectoral fins occur as the undulating wave varies in three dimensions; pectoral fin kinematics and changes in waveform with swimming speed cannot be fully quantified by two-dimensional analyses of the fin margin. We present the first three-dimensional analysis of undulatory rajiform locomotion in a batoid, the freshwater stingray Potamotrygon orbignyi. Using three cameras (250 frames s(-1)), we gathered three-dimensional excursion data from 31 points on the pectoral fin during swimming at 1.5 and 2.5 disc lengths s(-1), describing the propulsive wave and contrasting waveforms between swimming speeds. Only a relatively small region of the pectoral fin (~25%) undulates with significant amplitude (>0.5 cm). Stingrays can maintain extreme lateral curvature of the distal fin margin in opposition to induced hydrodynamic loads, 'cupping' the edge of the pectoral fin into the flow, with potential implications for drag reduction. Wave amplitude increases across both anteroposterior and mediolateral fin axes. Along the anteroposterior axis, amplitude increases until the wave reaches mid-disc and then remains constant, in contrast to angulliform patterns of continuous amplitude increase. Increases in swimming speed are driven by both wave frequency and wavespeed, though multivariate analyses reveal a secondary role for amplitude. PMID:22693031
Shin, Dong Sun; Jang, Hae Gwon; Hwang, Sung Bae; Har, Dong-Hwan; Moon, Young Lae; Chung, Min Suk
2013-01-01
In the Visible Korean project, serially sectioned images of the pelvis were made from a female cadaver. Outlines of significant structures in the sectioned images were drawn and stacked to build surface models. To improve the accessibility and informational content of these data, a five-step process was designed and implemented. First, 154 pelvic structures were outlined with additional surface reconstruction to prepare the image data. Second, the sectioned and outlined images (in a browsing software) as well as the surface models (in a PDF file) were placed on the Visible Korean homepage in a readily-accessible format. Third, all image data were visualized with interactive elements to stimulate creative learning. Fourth, two-dimensional (2D) images and three-dimensional (3D) models were superimposed on one another to provide context and spatial information for students viewing these data. Fifth, images were designed such that structure names would be shown when the mouse pointer hovered over the 2D images or the 3D models. The state-of-the-art sectioned images, outlined images, and surface models, arranged and systematized as described in this study, will aid students in understanding the anatomy of female pelvis. The graphic data accompanied by corresponding magnetic resonance images and computed tomographs are expected to promote the production of 3D simulators for clinical practice. PMID:23463707
Wu, Jun; Xia, Jun; Lei, Wei; Wang, Baoping
2011-01-01
Background After comprehensive study of various superhydrophobic phenomena in nature, it is no longer a puzzle for researchers to realize such fetching surfaces. However, the different types of artificial surfaces may get wetted and lose its water repellence if there exist defects or the liquid is under pressure. With respect to the industry applications, in which the resistance of wetting transition is critical important, new nanostructure satisfied a certain geometric criterion should be designed to hold a stable gas film at the base area to avoid the wet transition. Methodology A thermal deposition method was utilized to produce a thin ZnO seeds membrane on the aluminum foil. And then a chemical self-assemble technology was developed in present work to fabricate three-dimensional (3D) hierarchical dune-like ZnO architecture based on the prepared seeds membrane. Results Hierarchical ZnO with micro scale dune-like structure and core-sharing nanosheets was generated. The characterization results showed that there exist plenty of gaps and interfaces among the micro-dune and nanosheets, and thus the surface area was enlarged by such a unique morphology. Benefited from this unique 3D ZnO hierarchical nanostructure, the obtained surface exhibited stable water repellency after modification with Teflon, and furthermore, based on solid theory analysis, such 3D ZnO nanostructure would exhibit excellent sensing performance. PMID:22194987
NASA Astrophysics Data System (ADS)
Miyazawa, Keisuke; Kobayashi, Naritaka; Watkins, Matthew; Shluger, Alexander L.; Amano, Ken-Ichi; Fukuma, Takeshi
2016-03-01
Hydration plays important roles in various solid-liquid interfacial phenomena. Very recently, three-dimensional scanning force microscopy (3D-SFM) has been proposed as a tool to visualise solvated surfaces and their hydration structures with lateral and vertical (sub) molecular resolution. However, the relationship between the 3D force map obtained and the equilibrium water density, ρ(r), distribution above the surface remains an open question. Here, we investigate this relationship at an interface of an inorganic mineral, fluorite, and water. The force maps measured in pure water are directly compared to force maps generated using the solvent tip approximation (STA) model and from explicit molecular dynamics simulations. The results show that the simulated STA force map describes the major features of the experimentally obtained force image. The agreement between the STA data and the experiment establishes the correspondence between the water density used as an input to the STA model and the experimental hydration structure and thus provides a tool to bridge the experimental force data and atomistic solvation structures. Further applications of this method should improve the accuracy and reliability of both interpretation of 3D-SFM force maps and atomistic simulations in a wide range of solid-liquid interfacial phenomena.Hydration plays important roles in various solid-liquid interfacial phenomena. Very recently, three-dimensional scanning force microscopy (3D-SFM) has been proposed as a tool to visualise solvated surfaces and their hydration structures with lateral and vertical (sub) molecular resolution. However, the relationship between the 3D force map obtained and the equilibrium water density, ρ(r), distribution above the surface remains an open question. Here, we investigate this relationship at an interface of an inorganic mineral, fluorite, and water. The force maps measured in pure water are directly compared to force maps generated using the solvent
NASA Astrophysics Data System (ADS)
Bergeron, Charles; Labelle, Hubert; Ronsky, Janet; Zernicke, Ronald
2005-04-01
Spinal curvature progression in scoliosis patients is monitored from X-rays, and this serial exposure to harmful radiation increases the incidence of developing cancer. With the aim of reducing the invasiveness of follow-up, this study seeks to relate the three-dimensional external surface to the internal geometry, having assumed that that the physiological links between these are sufficiently regular across patients. A database was used of 194 quasi-simultaneous acquisitions of two X-rays and a 3D laser scan of the entire trunk. Data was processed to sets of datapoints representing the trunk surface and spinal curve. Functional data analyses were performed using generalized Fourier series using a Haar basis and functional minimum noise fractions. The resulting coefficients became inputs and outputs, respectively, to an array of support vector regression (SVR) machines. SVR parameters were set based on theoretical results, and cross-validation increased confidence in the system's performance. Predicted lateral and frontal views of the spinal curve from the back surface demonstrated average L2-errors of 6.13 and 4.38 millimetres, respectively, across the test set; these compared favourably with measurement error in data. This constitutes a first robust prediction of the 3D spinal curve from external data using learning techniques.
Kim, Ki Woo; Kim, Du-Hyun; Han, Sim-Hee; Lee, Jae-Cheon; Kim, Pan-Gi
2010-08-01
Three-dimensional surface topography of needle stomatal complexes was investigated in Pinus rigida, Pinus taeda, and their interspecific hybrid Pinus rigitaeda. The stomatal complexes of P. rigida appeared to be sunken and ca. 15 microm deep by white light scanning interferometry. Stomatal grooves were evident in P. taeda along the stomata and amounted to ca. 5 microm deep. The centers of stomata maintained the similar height to the stomatal apertures. Meanwhile, the stomatal complexes of P. rigitaeda (ca. 15 microm deep) were characterized by distinct stomatal grooves and sunken stomatal chambers. In addition, field emission scanning electron microscopy revealed the stomatal complexes of P. rigida partially filled with epicuticular waxes. It was common to observe distinct stomatal grooves and chamber-filled stomata on P. taeda needles. The stomatal complexes of P. rigitaeda had the distinct stomatal grooves and were partially filled with wax tubules and rodlets. Surface roughness measurements of stomatal complexes showed higher levels of roughness from P. rigida and P. rigitaeda than that from P. taeda. These results indicate that the hybrid species P. rigitaeda showed intermediacy in surface characteristics between the parent species, suggesting the genetic control of needle stomatal complexes in the hybrid species. PMID:20452778
Fang, Hui; Zhang, Chang Xing; Liu, Luo; Zhao, Yong Mei; Xu, Hai Jun
2015-02-15
Multifunctional Ag nanoparticle-decorated TiO2 nanorod arrays were prepared by two simple processes. TiO2 nanorod arrays were first fabricated by the hydrothermal route and then Ag nanoparticles were decorated on the nanorods by the chemical reduction impregnation method. Three-dimensional Ag/TiO2 arrays were used as an active substrate for surface-enhanced Raman scattering (SERS). The results show that the detection limit for rhodamine 6G (R6G) was as low as 10(-7)M and the Raman enhancement factor was as large as 10(5). After calibrating the Raman peak intensities of R6G, it could be quantitatively detected. More importantly, the photocatalytic activity of TiO2 provides a self-cleaning capability to the SERS substrate, which can be recycled and used to degrade many Ag surface adsorbates such as R6G, methyl orange, Congo red, and methylene blue after exposure to visible light. The absorbed small molecules can all be rapidly and completely removed from the SERS substrate, which has been successfully reused four times without a decrease in accuracy or sensitivity. Our results reveal that the unique recyclable property not only paves a new way to solve the single-use problem of traditional SERS substrates but also provides more SERS platforms for multiple detections of other organic molecular species. PMID:25282397
Lin, Shu-Ping; Kyriakides, Themis R; Chen, Jia-Jin J
2009-06-01
Despite many successful applications of microelectrode arrays (MEAs), typical two-dimensional in-vitro cultures do not project the full scale of the cell growth environment in the three-dimensional (3D) in-vivo setting. This study aims to on-line monitor in-vitro cell growth in a 3D matrix on the surface-modified MEAs with a dynamic perfusion culture system. A 3D matrix consisting of poly(ethylene glycol) hydrogel supplemented with poly-D-lysine was subsequently synthesized in situ on the self-assembled monolayer modified MEAs. FTIR spectrum analysis revealed a peak at 2100 cm(-1) due to the degradation of the structure of the 3D matrix. After 2 wks, microscopic examination revealed that the non-degraded area was around 1500 microm(2) and provided enough space for cell growth. Fluorescence microscopy revealed that the degraded 3D matrix was non-cytotoxic allowing the growth of NIH3T3 fibroblasts and cortical neurons in vitro. Time-course changes of total impedance including resistance and reactance were recorded for 8 days to evaluate the cell growth in the 3D matrix on the MEA. A consistent trend reflecting changes of reactance and total impedance was observed. These in-vitro assays demonstrate that our 3D matrix can construct a biomimetic system for cell growth and analysis of cell surface interactions. PMID:19344948
Topology of three-dimensional separated flows
NASA Technical Reports Server (NTRS)
Tobak, M.; Peake, D. J.
1981-01-01
Based on the hypothesis that patterns of skin-friction lines and external streamlines reflect the properties of continuous vector fields, topology rules define a small number of singular points (nodes, saddle points, and foci) that characterize the patterns on the surface and on particular projections of the flow (e.g., the crossflow plane). The restricted number of singular points and the rules that they obey are considered as an organizing principle whose finite number of elements can be combined in various ways to connect together the properties common to all steady three dimensional viscous flows. Introduction of a distinction between local and global properties of the flow resolves an ambiguity in the proper definition of a three dimensional separated flow. Adoption of the notions of topological structure, structural stability, and bifurcation provides a framework to describe how three dimensional separated flows originate and succeed each other as the relevant parameters of the problem are varied.
NASA Astrophysics Data System (ADS)
Hattori, Azusa N.; Hattori, Ken; Takemoto, Shohei; Daimon, Hiroshi; Tanaka, Hidekazu
2016-02-01
The realization of atomically flat side-surfaces, which are vertical planes on a substrate, would make an enormous contribution to a paradigm shift from two-dimensional planar film structures to three-dimensional (3D) nanostructures. In this paper, we demonstrate the successful creation of well-defined Si{111}7 × 7 side-surfaces on a 3D-architected Si(110) substrate by the combination of 3D Si patterning and surface preparation techniques, as confirmed by reflection high-energy electron diffraction (RHEED). The RHEED patterns consisted of 7 × 7 diffraction spots from the Si{111} side-surfaces and 2 × 16 diffraction spots from the Si(110) top/bottom surface. We also performed the deposition of metals (Au and Ag) onto the side-surfaces, leading to the formation of Si(1 bar 11) √3 × √3R30°-Au and Si(1 1 bar 1 bar) √3 × √3R30°-Ag structures. This is the first demonstration indicating super-reconstructions of such well-defined side-surfaces.
NASA Astrophysics Data System (ADS)
Ball, W. H.; Beeck, B.; Cameron, R. H.; Gizon, L.
2016-08-01
Context. Space-based observations of solar-like oscillators have identified large numbers of stars in which many individual mode frequencies can be precisely measured. However, current stellar models predict oscillation frequencies that are systematically affected by simplified modelling of the near-surface layers. Aims: We use three-dimensional radiation hydrodynamics simulations to better model the near-surface equilibrium structure of dwarfs with spectral types F3, G2, K0 and K5, and examine the differences between oscillation mode frequencies computed in stellar models with and without the improved near-surface equilibrium structure. Methods: We precisely match stellar models to the simulations' gravities and effective temperatures at the surface, and to the temporally- and horizontally-averaged densities and pressures at their deepest points. We then replace the near-surface structure with that of the averaged simulation and compute the change in the oscillation mode frequencies. We also fit the differences using several parametric models currently available in the literature. Results: The surface effect in the stars of solar-type and later is qualitatively similar and changes steadily with decreasing effective temperature. In particular, the point of greatest frequency difference decreases slightly as a fraction of the acoustic cut-off frequency and the overall scale of the surface effect decreases. The surface effect in the hot, F3-type star follows the same trend in scale (i.e. it is larger in magnitude) but shows a different overall variation with mode frequency. We find that a two-term fit using the cube and inverse of the frequency divided by the mode inertia is best able to reproduce the surface terms across all four spectral types, although the scaled solar term and a modified Lorentzian function also match the three cooler simulations reasonably well. Conclusions: Three-dimensional radiation hydrodynamics simulations of near-surface convection can be
NASA Astrophysics Data System (ADS)
Nissen, Edwin; Krishnan, Aravindhan K.; Arrowsmith, J. Ramón; Saripalli, Srikanth
2012-08-01
The recent explosion in sub-meter resolution airborne LiDAR data raises the possibility of mapping detailed changes to Earth's topography. We present a new method that determines three-dimensional (3-D) coseismic surface displacements and rotations from differencing pre- and post-earthquake airborne LiDAR point clouds using the Iterative Closest Point (ICP) algorithm. Tested on simulated earthquake displacements added to real LiDAR data along the San Andreas Fault, the method reproduces the input deformation for a grid size of ∼50 m with horizontal and vertical accuracies of ∼20 cm and ∼4 cm, values that mimic errors in the original spot height measurements. The technique also measures rotations directly, resolving the detailed kinematics of distributed zones of faulting where block rotations are common. By capturing near-fault deformation in 3-D, the method offers new constraints on shallow fault slip and rupture zone deformation, in turn aiding research into fault zone rheology and long-term earthquake repeatability.
NASA Astrophysics Data System (ADS)
Ajili, Y.; Abdallah, D. Ben; Al-Mogren, M. Mogren; Francisco, J. S.; Hochlaf, M.
2016-05-01
Three-dimensional potential energy surface (3D-PES) of the HNS-He interacting system in Jacobi coordinates is mapped using high-level ab initio theory. These computations are performed at the explicitly correlated coupled cluster method with single, double and perturbative triple excitations (CCSD(T)-F12) in conjunction with the augmented correlation-consistent aug-cc-pVTZ basis set. The 3D-PES is incorporated into quantum dynamical computations to treat the nuclear motions, where HNS is considered as a rigid rotator colliding with He. Cross-sections for transitions among the first twenty nine rotational levels of HNS (up to jKaKc = 92,8) are calculated using the quantum exact close-coupling method for total energies <1000 cm-1 and using the coupled state approximation for higher energies. Collisional rate constants for temperatures ranging from 5 to 200 K are deduced. A clear propensity rule in favour of Δj = -2 rotational transitions is observed. These rate coefficients are of great importance for the detection of HNS in interstellar medium.
Luo, Xisheng; Guan, Ben; Si, Ting; Zhai, Zhigang; Wang, Xiansheng
2016-01-01
The Richmyer-Meshkov instability of a three-dimensional (3D) SF_{6}-air single-mode interface with a minimum-surface feature is investigated experimentally. The interface produced by the soap film technique is subjected to a planar shock and the evolution of the shocked interface is captured by time-resolved schlieren photography. Different from the light-heavy single-mode case, a phase inversion occurs in the shock-interface interaction and a bubblelike structure is observed behind the shocked interface, which may be ascribed to the difference in pressure perturbation at different planes. The superimposition of spikelike forward-moving jets forms a complex structure, indicating a distinctly 3D effect. Quantitatively, it is also found that the instability at the symmetry plane grows much slower than the prediction of two-dimensional linear model, but matches the extended 3D linear and nonlinear models accounting for the curvature effects. Therefore, the opposite curvatures of the 3D interface are beneficial for suppressing the growth of the instability. PMID:26871149
NASA Astrophysics Data System (ADS)
Luo, Xisheng; Guan, Ben; Si, Ting; Zhai, Zhigang; Wang, Xiansheng
2016-01-01
The Richmyer-Meshkov instability of a three-dimensional (3D) SF6-air single-mode interface with a minimum-surface feature is investigated experimentally. The interface produced by the soap film technique is subjected to a planar shock and the evolution of the shocked interface is captured by time-resolved schlieren photography. Different from the light-heavy single-mode case, a phase inversion occurs in the shock-interface interaction and a bubblelike structure is observed behind the shocked interface, which may be ascribed to the difference in pressure perturbation at different planes. The superimposition of spikelike forward-moving jets forms a complex structure, indicating a distinctly 3D effect. Quantitatively, it is also found that the instability at the symmetry plane grows much slower than the prediction of two-dimensional linear model, but matches the extended 3D linear and nonlinear models accounting for the curvature effects. Therefore, the opposite curvatures of the 3D interface are beneficial for suppressing the growth of the instability.
Khan, Waqar Azeem; Khan, Masood; Malik, Rabia
2014-01-01
This article addresses the steady three-dimensional flow of an Oldroyd-B nanofluid over a bidirectional stretching surface with heat generation/absorption effects. Suitable similarity transformations are employed to reduce the governing partial differential equations into coupled nonlinear ordinary differential equations. These nonlinear ordinary differential equations are then solved analytically by using the homotpy analysis method (HAM). Graphically results are presented and discussed for various parameters, namely, Deborah numbers β1 and β2, heat generation/absorption parameter λ, Prandtl parameter Pr, Brownian motion parameters Nb, thermophoresis parameter Nt and Lewis number Le. We have seen that the increasing values of the Brownian motion parameter Nt and thermophoresis parameter Nt leads to an increase in the temperature field and thermal boundary layer thickness while the opposite behavior is observed for concentration field and concentration boundary layer thickness. To see the validity of the present work, the numerical results are compared with the analytical solutions obtained by Homotopy analysis method and noted an excellent agreement for the limiting cases. PMID:25170945
Kikinis, R; Shenton, M E; Gerig, G; Hokama, H; Haimson, J; O'Donnell, B F; Wible, C G; McCarley, R W; Jolesz, F A
1994-11-21
Neuroanatomical and histological findings from post-mortem brains, as well as in vivo findings from magnetic resonance imaging (MRI) studies, suggest the presence of morphologic temporal lobe abnormalities in schizophrenia. To determine whether or not sulco-gyral pattern abnormalities in the temporal lobe could be detected in vivo, we applied computerized surface rendering techniques to MR data sets in order to make both qualitative and quantitative analyses of three-dimensional reconstructions of the temporal and frontal cortex in 15 schizophrenic patients and 15 normal controls. The qualitative analysis, based on a visual classification of the temporal lobe sulco-gyral pattern by 4 raters blind to diagnosis, showed that in schizophrenics there was a more vertical orientation to the sulci in the left temporal lobe, with an interrupted course of sulci due to gyri coursing across the sulci. Normal controls, in contrast, showed a more horizontal orientation with no interruptions. These findings were supported by the quantitative analysis, where more sulcal lines, representing an interrupted course of sulci, were observed in the temporal lobes (more pronounced on the left) in schizophrenics than in normal controls. These data suggest that some of the abnormalities observed in schizophrenia may have their origin in alterations occurring during the course of neurodevelopment when the sulco-gyral pattern is determined. PMID:7891892
NASA Technical Reports Server (NTRS)
Hansen, Arthur G.
1958-01-01
Analysis is presented on the possible similarity solutions of the three-dimensional, laminar, incompressible, boundary-layer equations referred to orthogonal, curvilinear coordinate systems. Requirements of the existence of similarity solutions are obtained for the following: flow over developable surface and flow over non-developable surfaces with proportional mainstream velocity components.
Kuwabata, Susumu; Minamimoto, Hiro; Inoue, Kosuke; Imanishi, Akihito; Hosoya, Ken; Uyama, Hiroshi; Torimoto, Tsukasa; Tsuda, Tetsuya; Seki, Shu
2014-01-01
Room-temperature ionic liquid (RTIL) has been widely investigated as a nonvolatile solvent as well as a unique liquid material because of its interesting features, e.g., negligible vapor pressure and high thermal stability. Here we report that a non-volatile polymerizable RTIL is a useful starting material for the fabrication of micro/nano-scale polymer structures with a focused-ion-beam (FIB) system operated under high-vacuum condition. Gallium-ion beam irradiation to the polymerizable 1-allyl-3-ethylimidazolium bis((trifluoromethane)sulfonyl)amide RTIL layer spread on a Si wafer induced a polymerization reaction without difficulty. What is interesting to note is that we have succeeded in provoking the polymerization reaction anywhere on the Si wafer substrate by using FIB irradiation with a raster scanning mode. By this finding, two- and three-dimensional micro/nano-scale polymer structure fabrications were possible at the resolution of 500,000 dpi. Even intricate three-dimensional micro/nano-figures with overhang and hollow moieties could be constructed at the resolution of approximately 100 nm. PMID:24430465
Minoshima, S.; Frey, K.A.; Koeppe, R.A.
1995-07-01
To improve the diagnostic performance of PET as an aid in evaluating patients suspected of having Alzheimer`s disease, the authors developed a fully automated method which generates comprehensive image presentations and objective diagnostic indices. Fluorine-18-fluorodeoxyglucose PET image sets were collected from 37 patients with probable Alzheimer`s disease (including questionable and mild dementia), 22 normal subjects and 5 patients with cerebrovascular disease. Following stereotactic anatomic standardization, metabolic activity on an individual`s PET image set was extracted to a set of predefined surface pixels (three-dimensional stereotactic surface projection, 3D-SSP), which was used in the subsequent analysis. A normal database was created by averaging extracted datasets of the normal subjects. Patients` datasets were compared individually with the normal database by calculating a Z-score on a pixel-by-pixel basis and were displayed in 3D-SSP views for visual inspections. Diagnostic indices were then generated based on averaged Z-scores for the association cortices. Patterns and severities of metabolic reduction in patients with probable Alzheimer`s disease were seen in the standard 3D-SSP views of extracted raw data and statistical Z-scores. When discriminating patients with probable Alzheimer`s disease from normal subjects, diagnostic indices of the parietal association cortex and unilaterally averaged parietal-temporal-frontal cortex showed sensitivities of 95% and 97%, respectively, with a specificity of 100%. Neither index yielded false-positive results for cerebrovascular disease. 3D-SSP enables quantitative data extraction and reliable localization of metabolic abnormalities by means of stereotactic coordinates. The proposed method is a promising approach for interpreting functional brain PET scans. 45 refs., 5 figs.
Horiuchi, Shohei; Choda, Naoki; Takahashi, Haruyuki; Sato, Tomomi; Taira, Hikaru; Mukai, Kei
2016-08-01
It is important to determine a critical micelle concentration (CMC) of a surfactant in a protein formulation for stabilizing the protein at maximum by preventing it from interfacial denaturation. There are several techniques for CMC determination. Among them, surface tensiometry is the most common approach because this has a long history and much data at many research fields. However, large amount of sample solution is usually required for the measurement (e.g., more than 1 mL is necessary when a standard reservoir like a glass petri dish is used). This is one of the hurdles for protein formulators because only a small amount of protein could be used at the early-stage development. In this research, we tried to minimize the required amount of sample solution for surface tension measurement by developing appropriate probe and reservoir using a three-dimensional printer (3D printer). The advantages and capabilities of 3D printer are (1) to control the shape and size of the printed material precisely, (2) to change the figure freely, and (3) to prepare the prototype quickly. After the experiments and thereby the refinement of probe as well as reservoir, we found that CMCs of polysorbate 20, polysorbate 80, and poloxamer 188 in water and protein formulations could be precisely detected using a probe 0.5 mm in diameter and small reservoir with a pocket of 7.5 mm in diameter/0.25 mm in depth which were made by a 3D printer. Furthermore, the required sample solution per each measurement could be reduced to 80 μL, which means more than 90% reduction against a standard reservoir. PMID:27321235
Wald, D.J.; Graves, R.W.
2001-01-01
Using numerical tests for a prescribed heterogeneous earthquake slip distribution, we examine the importance of accurate Green's functions (GF) for finite fault source inversions which rely on coseismic GPS displacements and leveling line uplift alone and in combination with near-source strong ground motions. The static displacements, while sensitive to the three-dimensional (3-D) structure, are less so than seismic waveforms and thus are an important contribution, particularly when used in conjunction with waveform inversions. For numerical tests of an earthquake source and data distribution modeled after the 1994 Northridge earthquake, a joint geodetic and seismic inversion allows for reasonable recovery of the heterogeneous slip distribution on the fault. In contrast, inaccurate 3-D GFs or multiple 1-D GFs allow only partial recovery of the slip distribution given strong motion data alone. Likewise, using just the GPS and leveling line data requires significant smoothing for inversion stability, and hence, only a blurred vision of the prescribed slip is recovered. Although the half-space approximation for computing the surface static deformation field is no longer justifiable based on the high level of accuracy for current GPS data acquisition and the computed differences between 3-D and half-space surface displacements, a layered 1-D approximation to 3-D Earth structure provides adequate representation of the surface displacement field. However, even with the half-space approximation, geodetic data can provide additional slip resolution in the joint seismic and geodetic inversion provided a priori fault location and geometry are correct. Nevertheless, the sensitivity of the static displacements to the Earth structure begs caution for interpretation of surface displacements, particularly those recorded at monuments located in or near basin environments. Copyright 2001 by the American Geophysical Union.
Kumazawa-Manita, Noriko; Katayama, Mariko; Hashikawa, Tsutomu; Iriki, Atsushi
2013-11-01
Degus (Octodon degus) are rodents that are becoming more widely used in the neuroscience field. Degus display several more complex behaviors than rats and mice, including complicated social behaviors, vocal communications, and tool usage with superb manual dexterity. However, relatively little information is known about the anatomy of degu brains. Therefore, for these complex behaviors to be correlated with specific brain regions, a contemporary atlas of the degu brain is required. This manuscript describes the construction of a three-dimensional (3D) volume rendered model of the degu brain that combines histological and magnetic resonance images. This atlas provides several advantages, including the ability to visualize the surface of the brain from any angle. The atlas also permits virtual cutting of brain sections in any plane and provides stereotaxic coordinates for all sections, to be beneficial for both experimental surgeries and radiological studies. The reconstructed 3D atlas is freely available online at: http://brainatlas.brain.riken.jp/degu/modules/xoonips/listitem.php?index_id=24 . PMID:23995563
Calculation of Surface Waves and Body Waves from an Explosion in a Three-Dimensional Stress Field
NASA Astrophysics Data System (ADS)
Stevens, J. L.; Thompson, T. W.
2013-12-01
Although the effect of tectonic prestress on explosion-generated surface waves has been discussed since the 1960's, until recently it has not been possible to directly calculate the seismic waves from an explosion in a three-dimensional stress field. We developed a 3D nonlinear finite element code designed for calculation of explosions in 3D heterogeneous media and incorporated the capability to perform explosion calculations in a prestressed medium. During the calculations we save displacements and stresses on a monitoring surface in the elastic region outside the nonlinear region, and then use the representation theorem to propagate the solution to regional and teleseismic distances. We have run calculations with and without tectonic release so that we can compare them and isolate the effects of tectonic release. We model the explosion Shoal, a 12.5 kiloton explosion detonated at 390 meters depth near Fallon, Nevada. This event had strong heterogeneity in near-field waveforms and is in a region under primarily extensional tectonic stress. There were three near-field shot level recording stations located in three directions each at about 590 meters from the shot. Including prestress consistent with the regional stress field causes variations in the calculated near-field waveforms similar to those observed in the Shoal data. The calculation with tectonic release also generates Love waves and a Rayleigh wave radiation pattern similar to those observed. We calculate both far-field and regional body waves and find very little difference between the P-waves for the cases with and without tectonic release. The effect of tectonic release on the SV-waves from the explosion is also small. However the calculation with tectonic release does generate SH-waves not present in the calculation without tectonic release. An important conclusion from these calculations relevant to nuclear monitoring is that while tectonic release can be expected to substantially change surface wave
Three dimensional interactive display
NASA Technical Reports Server (NTRS)
Vranish, John M. (Inventor)
2005-01-01
A three-dimensional (3-D) interactive display and method of forming the same, includes a transparent capaciflector (TC) camera formed on a transparent shield layer on the screen surface. A first dielectric layer is formed on the shield layer. A first wire layer is formed on the first dielectric layer. A second dielectric layer is formed on the first wire layer. A second wire layer is formed on the second dielectric layer. Wires on the first wire layer and second wire layer are grouped into groups of parallel wires with a turnaround at one end of each group and a sensor pad at the opposite end. An operational amplifier is connected to each of the sensor pads and the shield pad biases the pads and receives a signal from connected sensor pads in response to intrusion of a probe. The signal is proportional to probe location with respect to the monitor screen.
Holly, J E
2000-01-01
The laws of physics explain many human misperceptions of whole-body passive self-motion. One classic misperception occurs in a rotating chair in the dark: If the chair is decelerated to a stop after a period of counterclockwise rotation, then a subject will typically perceive clockwise rotation. The laws of physics show that, indeed, a clockwise rotation would be perceived even by a perfect processor of angular acceleration information, assuming that the processor is initialized (prior to the deceleration) with a typical subject's initial perception - of no rotation in this case. The motion perceived by a perfect acceleration processor serves as a baseline by which to judge human self-motion perception; this baseline makes a rough prediction and also forms a basis for comparison, with uniquely physiological properties of perception showing up as deviations from the baseline. These same principles, using the motion perceived by a perfect acceleration processor as a baseline, are used in the present paper to investigate complex motions that involve simultaneous linear and angular accelerations with a changing axis of rotation. Baselines - motions that would be perceived by a perfect acceleration processor, given the same initial perception (prior to the motion of interest) as that of a typical subject - are computed for the acceleration and deceleration stages of centrifuge runs in which the human carriage tilts along with the vector resultant of the centripetal and gravity vectors. The computations generate a three-dimensional picture of the motion perceived by a perfect acceleration processor, by simultaneously using all six interacting degrees of freedom (three angular and three linear) and taking into account the non-commutativity of rotations in three dimensions. The resulting three-dimensional baselines predict stronger perceptual effects during deceleration than during acceleration, despite the equal magnitudes (with opposite direction) of forces on the
Terino, Edward O; Edward, Michael
2008-07-01
Recent advances in the technology of implant designs and shapes, as well as improved understanding of the principles of facial aesthetics, give the plastic surgeon, for the first time, tools to precisely and permanently change faces in specific areas and with minimum morbidity. Cosmetic facial surgeons must learn and understand the zonal anatomy of the malar-midface region to be prepared for growing patient demands regarding analysis and alteration of facial cheek contours. This article describes and illustrates contemporary technology that uses alloplastic implants throughout the face. Three-dimensional changes in facial form and shape using alloplastic augmentation techniques are essential for creating aesthetic beauty and are the "final chapter" of the development of cosmetic facial surgery. PMID:18558238
NASA Technical Reports Server (NTRS)
Katsanis, T.
1972-01-01
Computer program, CHANEL, can obtain quasi-three-dimensional solutions in any well-guided channel. Conditions that can be handled by program that could not be handled previously are nonuniform inlet temperature, pressure, prewhirl, nonaxial flow where meridional flow angle, meridional stream-line curvature, and radius can vary as desired from hub to tip.
NASA Astrophysics Data System (ADS)
Ogawa, Masaru
2014-12-01
In order to assure structural integrity for operating welded structures, it is necessary to evaluate crack growth rate and crack propagation direction for each observed crack non-destructively. Here, three dimensional (3D) welding residual stresses must be evaluated to predict crack propagation. Today, X-ray diffraction is used and the ultrasonic method has been proposed as non-destructive method to measure residual stresses. However, it is impossible to determine residual stress distributions in the thickness direction. Although residual stresses through a depth of several tens of millimeters can be evaluated non-destructively by neutron diffraction, it cannot be used as an on-site measurement technique. This is because neutron diffraction is only available in special irradiation facilities. Author pays attention to the bead flush method based on the eigenstrain methodology. In this method, 3D welding residual stresses are calculated by an elastic Finite Element Method (FEM) analysis from eigenstrains which are evaluated by an inverse analysis from released strains by strain gauges in the removal of the reinforcement of the weld. Here, the removal of the excess metal can be regarded as non-destructive treatment because toe of weld which may become crack starters can be eliminated. The effectiveness of the method has been proven for welded plates and pipes even with relatively lower bead height. In actual measurements, stress evaluation accuracy becomes poorer because measured values of strain gauges are affected by processing strains on the machined surface. In the previous studies, the author has developed the bead flush method that is free from the influence of the affecting strains by using residual strains on surface by X-ray diffraction. However, stress evaluation accuracy is not good enough because of relatively poor measurement accuracy of X-ray diffraction. In this study, a method to improve the estimation accuracy of residual stresses in this method is
Suresh, Niraj; Stephens, Sean A; Adams, Lexor; Beck, Anthon N; McKinney, Adriana L; Varga, Tamas
2016-01-01
Plant roots play a critical role in plant-soil-microbe interactions that occur in the rhizosphere, as well as processes with important implications to climate change and crop management. Quantitative size information on roots in their native environment is invaluable for studying root growth and environmental processes involving plants. X-ray computed tomography (XCT) has been demonstrated to be an effective tool for in situ root scanning and analysis. We aimed to develop a costless and efficient tool that approximates the surface and volume of the root regardless of its shape from three-dimensional (3D) tomography data. The root structure of a Prairie dropseed (Sporobolus heterolepis) specimen was imaged using XCT. The root was reconstructed, and the primary root structure was extracted from the data using a combination of licensed and open-source software. An isosurface polygonal mesh was then created for ease of analysis. We have developed the standalone application imeshJ, generated in MATLAB(1), to calculate root volume and surface area from the mesh. The outputs of imeshJ are surface area (in mm(2)) and the volume (in mm(3)). The process, utilizing a unique combination of tools from imaging to quantitative root analysis, is described. A combination of XCT and open-source software proved to be a powerful combination to noninvasively image plant root samples, segment root data, and extract quantitative information from the 3D data. This methodology of processing 3D data should be applicable to other material/sample systems where there is connectivity between components of similar X-ray attenuation and difficulties arise with segmentation. PMID:27168248
Bormann, Therese; Schulz, Georg; Deyhle, Hans; Beckmann, Felix; de Wild, Michael; Küffer, Jürg; Münch, Christoph; Hoffmann, Waldemar; Müller, Bert
2014-02-01
Appropriate mechanical stimulation of bony tissue enhances osseointegration of load-bearing implants. Uniaxial compression of porous implants locally results in tensile and compressive strains. Their experimental determination is the objective of this study. Selective laser melting is applied to produce open-porous NiTi scaffolds of cubic units. To measure displacement and strain fields within the compressed scaffold, the authors took advantage of synchrotron radiation-based micro computed tomography during temperature increase and non-rigid three-dimensional data registration. Uniaxial scaffold compression of 6% led to local compressive and tensile strains of up to 15%. The experiments validate modeling by means of the finite element method. Increasing the temperature during the tomography experiment from 15 to 37°C at a rate of 4 K h(-1), one can locally identify the phase transition from martensite to austenite. It starts at ≈ 24°C on the scaffolds bottom, proceeds up towards the top and terminates at ≈ 34°C on the periphery of the scaffold. The results allow not only design optimization of the scaffold architecture, but also estimation of maximal displacements before cracks are initiated and of optimized mechanical stimuli around porous metallic load-bearing implants within the physiological temperature range. PMID:24257506
Hassani Gangaraj, S. Ali; Nemilentsau, Andrei; Hanson, George W.
2016-01-01
We have investigated one-way surface plasmon-polaritons (SPPs) at the interface of a continuum magnetoplasma material and metal, in the presence of three-dimensional surface defects. Bulk electromagnetic modes of continuum materials have Chern numbers, analogous to those of photonic crystals. This can lead to the appearance of topologically-protected surface modes at material interfaces, propagating at frequencies inside the bandgap of the bulk materials. Previous studies considered two-dimensional structures; here we consider the effect of three-dimensional defects, and show that, although backward propagation/reflection cannot occur, side scattering does take place and has significant effect on the propagation of the surface mode. Several different waveguiding geometries are considered for reducing the effects of side-scattering, and we also consider the effects of metal loss. PMID:27444542
NASA Astrophysics Data System (ADS)
Hassani Gangaraj, S. Ali; Nemilentsau, Andrei; Hanson, George W.
2016-07-01
We have investigated one-way surface plasmon-polaritons (SPPs) at the interface of a continuum magnetoplasma material and metal, in the presence of three-dimensional surface defects. Bulk electromagnetic modes of continuum materials have Chern numbers, analogous to those of photonic crystals. This can lead to the appearance of topologically-protected surface modes at material interfaces, propagating at frequencies inside the bandgap of the bulk materials. Previous studies considered two-dimensional structures; here we consider the effect of three-dimensional defects, and show that, although backward propagation/reflection cannot occur, side scattering does take place and has significant effect on the propagation of the surface mode. Several different waveguiding geometries are considered for reducing the effects of side-scattering, and we also consider the effects of metal loss.
Hassani Gangaraj, S Ali; Nemilentsau, Andrei; Hanson, George W
2016-01-01
We have investigated one-way surface plasmon-polaritons (SPPs) at the interface of a continuum magnetoplasma material and metal, in the presence of three-dimensional surface defects. Bulk electromagnetic modes of continuum materials have Chern numbers, analogous to those of photonic crystals. This can lead to the appearance of topologically-protected surface modes at material interfaces, propagating at frequencies inside the bandgap of the bulk materials. Previous studies considered two-dimensional structures; here we consider the effect of three-dimensional defects, and show that, although backward propagation/reflection cannot occur, side scattering does take place and has significant effect on the propagation of the surface mode. Several different waveguiding geometries are considered for reducing the effects of side-scattering, and we also consider the effects of metal loss. PMID:27444542
Haraguchi, Tomoyuki; Otsubo, Kazuya; Sakata, Osami; Kawaguchi, Shogo; Fujiwara, Akihiko; Kitagawa, Hiroshi
2016-05-21
We describe the synthesis and sorption properties of a new metal-organic framework (MOF), Fe(H2O)2(bpy)[Pt(CN)4]·H2O (bpy = 4,4'-bipyridine), with a three-dimensional accordion-like structure. Although crystalline oriented MOF thin films reported to date have been mainly limited to a layer-type structure, we succeeded in the fabrication of its crystalline oriented thin film. PMID:27063003
NASA Astrophysics Data System (ADS)
Perez-Fontes, S. E.; Sohn, H. Y.
2012-04-01
A chemical vapor synthesis (CVS) process for synthesizing aluminum nanopowder as a reactant for various hydrogen-storage materials was simulated using a mathematical technique that combines computational fluid dynamics (CFD) with the population balance model. In this process, aluminum powder is produced by reacting aluminum chloride with magnesium in the vapor phase. The CFD model solves the three-dimensional (3-D) turbulent governing equations of fluid flow, heat and mass transfer, and chemical kinetics in a multiphase domain. The population balance model incorporates nucleation, surface growth, and coagulation. The nucleation rate is computed using an expression from the classical nucleation theory. The growth rate is obtained by the combined effect of vapor condensation and coagulation. A comparison of the model predictions with the available experimental data showed good agreement under different operating conditions without the need of adjustable parameters. According to the results, the final particle size is determined by particle coagulation in this particular CVS process. The new model proposed in this article can be applied to other similar systems with confidence even without the need of any experimental data and can be used for scale-up of the process.
Yang, Yukun; Cao, Yaoyu; Wang, Xiaomin; Fang, Guozhen; Wang, Shuo
2015-02-15
In this work, we presented a three-dimensional (3D) molecularly imprinted electrochemical sensor (MIECS) with novel strategy for ultrasensitive and specific quantification of metolcarb based on prussian blue (PB) mediated amplification combined with signal enhancement of ordered mesoporous carbon. The molecularly imprinted polymers were synthesized by electrochemically induced redox polymerization of para aminobenzoic acid (p-ABA) in the presence of template metolcarb. Ordered mesoporous carbon material (CMK-3) was introduced to enhance the electrochemical response by improving the structure of the modified electrodes and facilitating charge transfer processes of PB which was used as an inherent electrochemical active probe. The modification process for the working electrodes of the MIECS was characterized by scanning electron microscope (SEM) and cyclic voltammetry (CV), and several important parameters controlling the performance of the MIECS were investigated and optimized in detail. The MIECS with 3D structure had the advantages of ease of preparation, high porous surface structure, speedy response, ultrasensitivity, selectivity, reliable stability, good reproducibility and repeatability. Under the optimal conditions, the MIECS offered an excellent current response for metolcarb in the linear response range of 5.0 × 10(-10)-1.0 × 10(-4) mol L(-1) and the limit of detection (LOD) was calculated to be 9.3 × 10 (-11)mol L(-1) (S/N = 3). The proposed MIECS has been successfully applied for the determination of metolcarb in real samples with satisfactory recoveries. Furthermore, the construction route of this ultrasensitive 3D MIECS may provide a guideline for the determination of non-electroactive analytes in environmental control and food safety. PMID:25240126
Ogurtani, Tarik Omer
2006-04-14
A theory of irreversible thermodynamics of curved surfaces and interfaces with triple junction singularities is elaborated to give a full consideration of the effects of the specific surface Gibbs free energy anisotropy in addition to the diffusional anisotropy, on the morphological evolution of surfaces and interfaces in crystalline solids. To entangle this intricate problem, the internal entropy production associated with arbitrary virtual displacements of triple junction and ordinary points on the interfacial layers, embedded in a multicomponent, multiphase, anisotropic composite continuum system, is formulated by adapting a mesoscopic description of the orientation dependence of the chemical potentials in terms of the rotational degree of freedom of individual microelements. The rate of local internal entropy production resulted generalized forces and conjugated fluxes not only for the grain boundary triple junction transversal and longitudinal movements, but also for the ordinary points. The natural combination of the mesoscopic approach coupled with the rigorous theory of irreversible thermodynamics developed previously by the global entropy production hypothesis yields a well-posed, nonlinear, moving free-boundary value problem in two-dimensional (2D) space, as a unified theory. The results obtained for 2D space are generalized into the three-dimensional continuum by utilizing the invariant properties of the vector operators in connection with the descriptions of curved surfaces in differential geometry. This mathematical model after normalization and scaling procedures may be easily adapted for computer simulation studies without introducing any additional phenomenological system parameters (the generalized mobilities), other than the enlarged concept of the surface stiffness. PMID:16626230
Fadeyev, V.; Haber, C.; Maul, C.; McBride, J.W.; Golden, M.
2004-04-20
Audio information stored in the undulations of grooves in a medium such as a phonograph disc record or cylinder may be reconstructed, without contact, by measuring the groove shape using precision optical metrology methods and digital image processing. The viability of this approach was recently demonstrated on a 78 rpm shellac disc using two dimensional image acquisition and analysis methods. The present work reports the first three dimensional reconstruction of mechanically recorded sound. The source material, a celluloid cylinder, was scanned using color coded confocal microscopy techniques and resulted in a faithful playback of the recorded information.
Magnetic field effect in three-dimensional flow of an Oldroyd-B nanofluid over a radiative surface
NASA Astrophysics Data System (ADS)
Shehzad, S. A.; Abdullah, Z.; Abbasi, F. M.; Hayat, T.; Alsaedi, A.
2016-02-01
This article investigates the convective heat and mass conditions in three-dimensional flow of an Oldroyd-B nanofluid. The stretched flow is electrically conducting in the presence of an applied magnetic field. Thermal radiation effects are accounted in the energy equation. The governing nonlinear problems are computed for the convergent approximate solutions. Influences of different parameters on the dimensionless temperature and nanoparticle concentration fields are shown and examined. Quantities of physical interest namely local Nusselt and Sherwood numbers are computed and analyzed numerically. Comparison in a limiting case is made with the previous published result and an excellent agreement is noted.
NASA Technical Reports Server (NTRS)
Kandula, M.; Haddad, G. F.; Chen, R.-H.
2006-01-01
Three-dimensional Navier-Stokes computational fluid dynamics (CFD) analysis has been performed in an effort to determine thermal boundary layer correction factors for circular convective heat flux gauges (such as Schmidt-Boelter and plug type)mounted flush in a flat plate subjected to a stepwise surface temperature discontinuity. Turbulent flow solutions with temperature-dependent properties are obtained for a free stream Reynolds number of 1E6, and freestream Mach numbers of 2 and 4. The effect of gauge diameter and the plate surface temperature have been investigated. The 3-D CFD results for the heat flux correction factors are compared to quasi-21) results deduced from constant property integral solutions and also 2-D CFD analysis with both constant and variable properties. The role of three-dimensionality and of property variations on the heat flux correction factors has been demonstrated.
NASA Technical Reports Server (NTRS)
Neuhauser, Daniel; Baer, Michael; Judson, Richard S.; Kouri, Donald J.
1989-01-01
The first successful application of the three-dimensional quantum body frame wave packet approach to reactive scattering is reported for the H + H2 exchange reaction on the LSTH potential surface. The method used is based on a procedure for calculating total reaction probabilities from wave packets. It is found that converged, vibrationally resolved reactive probabilities can be calculated with a grid that is not much larger than required for the pure inelastic calculation. Tabular results are presented for several energies.
Hobbs, Robert F.; McNutt, Todd; Baechler, Sebastien; He Bin; Esaias, Caroline E.; Frey, Eric C.; Loeb, David M.; Wahl, Richard L.; Shokek, Ori; Sgouros, George
2011-07-15
Purpose: Effective cancer treatment generally requires combination therapy. The combination of external beam therapy (XRT) with radiopharmaceutical therapy (RPT) requires accurate three-dimensional dose calculations to avoid toxicity and evaluate efficacy. We have developed and tested a treatment planning method, using the patient-specific three-dimensional dosimetry package 3D-RD, for sequentially combined RPT/XRT therapy designed to limit toxicity to organs at risk. Methods and Materials: The biologic effective dose (BED) was used to translate voxelized RPT absorbed dose (D{sub RPT}) values into a normalized total dose (or equivalent 2-Gy-fraction XRT absorbed dose), NTD{sub RPT} map. The BED was calculated numerically using an algorithmic approach, which enabled a more accurate calculation of BED and NTD{sub RPT}. A treatment plan from the combined Samarium-153 and external beam was designed that would deliver a tumoricidal dose while delivering no more than 50 Gy of NTD{sub sum} to the spinal cord of a patient with a paraspinal tumor. Results: The average voxel NTD{sub RPT} to tumor from RPT was 22.6 Gy (range, 1-85 Gy); the maximum spinal cord voxel NTD{sub RPT} from RPT was 6.8 Gy. The combined therapy NTD{sub sum} to tumor was 71.5 Gy (range, 40-135 Gy) for a maximum voxel spinal cord NTD{sub sum} equal to the maximum tolerated dose of 50 Gy. Conclusions: A method that enables real-time treatment planning of combined RPT-XRT has been developed. By implementing a more generalized conversion between the dose values from the two modalities and an activity-based treatment of partial volume effects, the reliability of combination therapy treatment planning has been expanded.
Three dimensional Dirac semimetals
NASA Astrophysics Data System (ADS)
Zaheer, Saad
We extend the physics of graphene to three dimensional systems by showing that Dirac points can exist on the Fermi surface of realistic materials in three dimensions. Many of the exotic electronic properties of graphene can be ascribed to the pseudorelativistic behavior of its charge carriers due to two dimensional Dirac points on the Fermi surface. We show that certain nonsymmorphic spacegroups exhibit Dirac points among the irreducible representations of the appropriate little group at high symmetry points on the surface of the Brillouin zone. We provide a list of all Brillouin zone momenta in the 230 spacegroups that can host Dirac points. We describe microscopic considerations necessary to design materials in one of the candidate spacegroups such that the Dirac point appears at the Fermi energy without any additional non-Dirac-like Fermi pockets. We use density functional theory based methods to propose six new Dirac semimetals: BiO 2 and SbO2 in the beta-cristobalite lattice (spacegroup 227), and BiCaSiO4, BiMgSiO4, BiAlInO 4, and BiZnSiO4 in the distorted spinels lattice (spacegroup 74). Additionally we derive effective Dirac Hamiltonians given group representative operators as well as tight binding models incorporating spin-orbit coupling. Finally we study the Fermi surface of zincblende (spacegroup 216) HgTe which is effectively point-like at Gamma in the Brillouin zone and exhibits accidental degeneracies along a threefold rotation axis. Whereas compressive strain gaps the band structure into a topological insulator, tensile strain shifts the accidental degeneracies away from Gamma and enlarges the Fermi surface. States on the Fermi surface exhibit nontrivial spin texture marked by winding of spins around the threefold rotation axis and by spin vortices indicating a change in the winding number. This is confirmed by microscopic calculations performed in tensile strained HgTe and Hg0.5Zn 0.5 Te as well as k.p theory. We conclude with a summary of recent
Xie, Lianghai Li, Lei; Wang, Jingdong; Zhang, Yiteng
2014-04-15
We present a three-dimensional, two-species (Ba{sup +} and H{sup +}) MHD model to study the early time behaviors of a barium release at about 1 R{sub E} like Combined Release and Radiation Effects Satellite G2, with emphasis placed on the three-dimensional evolution of the barium cloud and its effects on the ambient plasma environment. We find that the perturbations caused by the cloud are the combined results of the initial injection, the radial expansion, and the diamagnetic effect and propagate as fast MHD waves in the magnetosphere. In return, the transverse expansion and the cross-B motion of barium ions are constrained by the magnetic force, which lead to a field-aligned striation of ions and the decoupling of these ions from the neutrals. Our simulation shows the formation and collapse of the diamagnetic cavity in the barium cloud. The estimated time scale for the cavity evolution might be much shorter if photoionization time scale and field aligned expansion of barium ions are considered. In addition, our two species MHD simulation also finds the snowplow effect resulting from the momentum coupling between barium ions and background H{sup +}, which creates density hole and bumps in the background H{sup +} when barium ions expanding along the magnetic field lines.
NASA Technical Reports Server (NTRS)
Lee, S. S.; Sengupta, S.; Tuann, S. Y.; Lee, C. R.
1980-01-01
The free-surface model presented is for tidal estuaries and coastal regions where ambient tidal forces play an important role in the dispersal of heated water. The model is time dependent, three dimensional, and can handle irregular bottom topography. The vertical stretching coordinate is adopted for better treatment of kinematic condition at the water surface. The results include surface elevation, velocity, and temperature. The model was verified at the Anclote Anchorage site of Florida Power Company. Two data bases at four tidal stages for winter and summer conditions were used to verify the model. Differences between measured and predicted temperatures are on an average of less than 1 C.
Schmidbauer, M.; Seydmohamadi, Sh.; Wang, Zh.M.; Mazur, Yu.I.; Salamo, G.J.; Grigoriev, D.; Schaefer, P.; Koehler, R.; Hanke, M.
2006-02-17
Anisotropic surface diffusion and strain are used to explain the formation of three-dimensional (In,Ga)As quantum dot lattices. The diffusion characteristics of the surface, coupled with the elastic anisotropy of the matrix, provides an excellent opportunity to influence the dot positions. In particular, quantum dots that are laterally organized into long chains or chessboard two-dimensional arrays vertically organized with strict vertical ordering or vertical ordering that is inclined to the sample surface normal are accurately predicted and observed.
NASA Technical Reports Server (NTRS)
Landis, W. J.; Hodgens, K. J.; Song, M. J.; Arena, J.; Kiyonaga, S.; Marko, M.; Owen, C.; McEwen, B. F.
1996-01-01
The interaction between collagen and mineral crystals in the normally calcifying leg tendons from the domestic turkey, Meleagris gallopavo, has been investigated at an ultrastructural level with conventional and high-voltage electron microscopy, computed tomography, and three-dimensional image reconstruction methods. Specimens treated by either aqueous or anhydrous techniques and resin-embedded were appropriately sectioned and regions of early tendon mineralization were photographed. On the basis of individual photomicrographs, stereoscopic pairs of images, and tomographic three-dimensional image reconstructions, platelet-shaped crystals may be demonstrated for the first time in association with the surface of collagen fibrils. Mineral is also observed in closely parallel arrays within collagen hole and overlap zones. The mineral deposition at these spatially distinct locations in the tendon provides insight into possible means by which calcification is mediated by collagen as a fundamental event in skeletal and dental formation among vertebrates.
NASA Technical Reports Server (NTRS)
Ramachandra, Sridhar M.; Bober, Lawrence J.; Khandelwal, Suresh
1987-01-01
Using the lifting surface theory and the acceleration potential method for the flow field of an axial turbocompressor stage, a recursive and a direct method are presented that make use of the eigenfunction solutions of the isolated rotor and stator to solve for the rotor-stator interaction problem. The net pressure distribution on the rotor and stator blades is represented by modified Birnbaum series, whose coefficients are determined using a matrix procedure and satisfying the boundary conditions on the surface of the blades. The relation between the matrix operators of the recursive and the direct methods is also shown. Expressions have been given for the blade circulation, the axial and tangential forces on the blade, the rotor power required, and the induced upwash velocity of the stage.
NASA Astrophysics Data System (ADS)
Igumnov, Leonid; Ipatov, Aleksandr; Belov, Aleksandr; Petrov, Andrey
2015-09-01
The report presents the development of the time-boundary element methodology and a description of the related software based on a stepped method of numerical inversion of the integral Laplace transform in combination with a family of Runge-Kutta methods for analyzing 3-D mixed initial boundary-value problems of the dynamics of inhomogeneous elastic and poro-elastic bodies. The results of the numerical investigation are presented. The investigation methodology is based on direct-approach boundary integral equations of 3-D isotropic linear theories of elasticity and poroelasticity in Laplace transforms. Poroelastic media are described using Biot models with four and five base functions. With the help of the boundary-element method, solutions in time are obtained, using the stepped method of numerically inverting Laplace transform on the nodes of Runge-Kutta methods. The boundary-element method is used in combination with the collocation method, local element-by-element approximation based on the matched interpolation model. The results of analyzing wave problems of the effect of a non-stationary force on elastic and poroelastic finite bodies, a poroelastic half-space (also with a fictitious boundary) and a layered half-space weakened by a cavity, and a half-space with a trench are presented. Excitation of a slow wave in a poroelastic medium is studied, using the stepped BEM-scheme on the nodes of Runge-Kutta methods.
Slyfield, C R; Niemeyer, K E; Tkachenko, E V; Tomlinson, R E; Steyer, G G; Patthanacharoenphon, C G; Kazakia, G J; Wilson, D L; Hernandez, C J
2009-10-01
Serial block face imaging is a microscopy technique in which the top of a specimen is cut or ground away and a mosaic of images is collected of the newly revealed cross-section. Images collected from each slice are then digitally stacked to achieve 3D images. The development of fully automated image acquisition devices has made serial block face imaging more attractive by greatly reducing labour requirements. The technique is particularly attractive for studies of biological activity within cancellous bone as it has the capability of achieving direct, automated measures of biological and morphological traits and their associations with one another. When used with fluorescence microscopy, serial block face imaging has the potential to achieve 3D images of tissue as well as fluorescent markers of biological activity. Epifluorescence-based serial block face imaging presents a number of unique challenges for visualizing bone specimens due to noise generated by sub-surface signal and local variations in tissue autofluorescence. Here we present techniques for processing serial block face images of trabecular bone using a combination of non-uniform illumination correction, precise tiling of the mosaic in each cross-section, cross-section alignment for vertical stacking, removal of sub-surface signal and segmentation. The resulting techniques allow examination of bone surface texture that will enable 3D quantitative measures of biological processes in cancellous bone biopsies. PMID:19772536
NASA Technical Reports Server (NTRS)
Johnston, S.
1984-01-01
Zachary Phys. Rev. A 29 (6), 3224 (1984) recently analyzed the instability of relativistic-electron helical trajectories in combined uniform axial and helical wiggler magnetic fields when the radial variation of the wiggler field is taken into account. It is shown here that the type 2 instability comprised of secular terms growing linearly in time, identified by Zachary and earlier by Diament Phys. Rev. A 23 (5), 2537 (1981), is an artifact of simple perturbation theory. A multiple-time-scale perturbation analysis reveals a nonsecular evolution on a slower time scale which accommodates an arbitrary initial perturbation. It is shown that, in the absence of exponential instability, the electron seeks a modified helical orbit more appropriate to its perturbed state and oscillates stably about it. Thus, the perturbed motion is oscillatory but nonsecular, and hence the helical orbits are stable.
NASA Technical Reports Server (NTRS)
Edwards, Jack R.; McRae, D. Scott; Bond, Ryan B.; Steffan, Christopher (Technical Monitor)
2003-01-01
The GTX program at NASA Glenn Research Center is designed to develop a launch vehicle concept based on rocket-based combined-cycle (RBCC) propulsion. Experimental testing, cycle analysis, and computational fluid dynamics modeling have all demonstrated the viability of the GTX concept, yet significant technical issues and challenges still remain. Our research effort develops a unique capability for dynamic CFD simulation of complete high-speed propulsion devices and focuses this technology toward analysis of the GTX response during critical mode transition events. Our principal attention is focused on Mode 1/Mode 2 operation, in which initial rocket propulsion is transitioned into thermal-throat ramjet propulsion. A critical element of the GTX concept is the use of an Independent Ramjet Stream (IRS) cycle to provide propulsion at Mach numbers less than 3. In the IRS cycle, rocket thrust is initially used for primary power, and the hot rocket plume is used as a flame-holding mechanism for hydrogen fuel injected into the secondary air stream. A critical aspect is the establishment of a thermal throat in the secondary stream through the combination of area reduction effects and combustion-induced heat release. This is a necessity to enable the power-down of the rocket and the eventual shift to ramjet mode. Our focus in this first year of the grant has been in three areas, each progressing directly toward the key initial goal of simulating thermal throat formation during the IRS cycle: CFD algorithm development; simulation of Mode 1 experiments conducted at Glenn's Rig 1 facility; and IRS cycle simulations. The remainder of this report discusses each of these efforts in detail and presents a plan of work for the next year.
NASA Astrophysics Data System (ADS)
Yung, Y. Y.; Choi, B. H.; Tang, K. T.
1980-01-01
Three dimensional quantum mechanical calculations are carried out for the reactive scattering of D+H2→DH+H on the ab initio potential energy surface calculated by Liu and Siegbahn and fitted by Truhlar and Horowitz. The differential and total cross sections as well as the S matrix elements are obtained from the adiabatic distorted wave method. Threshold energy, cross sections and product distributions over final states are all in good agreement with experimental measurements. Results are also compared with the corresponding ones obtained on the Porter-Karplus and the Yates-Lester semi-empirical surfaces.
NASA Astrophysics Data System (ADS)
Kalkal, Yashvir; Kumar, Vinit
2016-06-01
In Čerenkov and Smith-Purcell free-electron lasers (FELs), a resonant interaction between the electron beam and the copropagating surface mode can produce a copious amount of coherent terahertz radiation. We perform a three-dimensional (3D) analysis of the surface mode, taking the effect of attenuation into account, and set up 3D Maxwell-Lorentz equations for both these systems. Based on this analysis, we determine the requirements on the electron beam parameters, i.e., beam emittance, beam size and beam current for the successful operation of a Čerenkov FEL.
Mhatre, Amol C; Tandur, Arundhati P; Reddy, Sumitra S; Karunakara, B C; Baswaraj, H
2015-01-01
Background: The purpose of this thesis is to present a practical and efficient clinical method of returning enamel to as near its original condition as possible following removal of bonded orthodontic attachments. The main objective of this study is to evaluate and compare the iatrogenic enamel damage caused by use of two different remnant removal techniques – sandblasting technique and carbide bur technique. Materials and Methods: 40 extracted premolar teeth were selected as sample. Premolar brackets were bonded on these teeth with two different types of light cure adhesive composite resin. The remnants present on these samples after debonding the brackets were removed with two different types of remnant removal techniques namely – Carbide bur technique and sandblasting technique. Then these treated surfaces were studied under Scanning electron microscope and three-dimensional profilometer for the damage caused to the enamel. Statistical analysis used Student’s t-tests. Results: The enamel surface structure after remnant removal with intraoral sandblasting is better than that after removal with a low-speed handpiece using tungsten carbide bur. Conclusion: Sandblasting can be an acceptable alternative to rotatory handpieces to restore the enamel surface to its near-original state and prevent permanent damage to the tooth. PMID:26668478
NASA Technical Reports Server (NTRS)
Martin, William G.; Cairns, Brian; Bal, Guillaume
2014-01-01
This paper derives an efficient procedure for using the three-dimensional (3D) vector radiative transfer equation (VRTE) to adjust atmosphere and surface properties and improve their fit with multi-angle/multi-pixel radiometric and polarimetric measurements of scattered sunlight. The proposed adjoint method uses the 3D VRTE to compute the measurement misfit function and the adjoint 3D VRTE to compute its gradient with respect to all unknown parameters. In the remote sensing problems of interest, the scalar-valued misfit function quantifies agreement with data as a function of atmosphere and surface properties, and its gradient guides the search through this parameter space. Remote sensing of the atmosphere and surface in a three-dimensional region may require thousands of unknown parameters and millions of data points. Many approaches would require calls to the 3D VRTE solver in proportion to the number of unknown parameters or measurements. To avoid this issue of scale, we focus on computing the gradient of the misfit function as an alternative to the Jacobian of the measurement operator. The resulting adjoint method provides a way to adjust 3D atmosphere and surface properties with only two calls to the 3D VRTE solver for each spectral channel, regardless of the number of retrieval parameters, measurement view angles or pixels. This gives a procedure for adjusting atmosphere and surface parameters that will scale to the large problems of 3D remote sensing. For certain types of multi-angle/multi-pixel polarimetric measurements, this encourages the development of a new class of three-dimensional retrieval algorithms with more flexible parametrizations of spatial heterogeneity, less reliance on data screening procedures, and improved coverage in terms of the resolved physical processes in the Earth?s atmosphere.
Bao, Luyao; Hu, Haibao; Wen, Jun; Sepri, Paavo; Luo, Kai
2016-01-01
A liquid in the vicinity of a solid-liquid interface (SLI) may exhibit complex structures. In this study, we used molecular dynamics simulations demonstrating for the first time that the liquid adjacent to the SLI can have a two-level structure in some cases: a major structure and a minor structure. Through a time-averaging process of molecular motions, we identified the type of the liquid structure by calculating positions of the maximum liquid density in three spatial dimensions, and these positions were found to distribute in many dispersed zones (called high-density zones (HDZs)). The major structure appears throughout the SLI, while the minor structure only occurs significantly within the third layer. Instead of the previously reported body-centered cubic (BCC) or face-centered-cubic (FCC) types, the major structure was found to show a body-centered tetragonal (BCT) type. The adjacent HDZs are connected by specific junctions, demonstrating that atoms diffuse along some particular high probability paths from one HDZ to another. By considering the three-dimensional liquid density distribution from the continuum point of view, more complete details of the structure and diffusive behavior of liquids in the SLI are also possible to be revealed. PMID:27430188
NASA Astrophysics Data System (ADS)
Bao, Luyao; Hu, Haibao; Wen, Jun; Sepri, Paavo; Luo, Kai
2016-07-01
A liquid in the vicinity of a solid-liquid interface (SLI) may exhibit complex structures. In this study, we used molecular dynamics simulations demonstrating for the first time that the liquid adjacent to the SLI can have a two-level structure in some cases: a major structure and a minor structure. Through a time-averaging process of molecular motions, we identified the type of the liquid structure by calculating positions of the maximum liquid density in three spatial dimensions, and these positions were found to distribute in many dispersed zones (called high-density zones (HDZs)). The major structure appears throughout the SLI, while the minor structure only occurs significantly within the third layer. Instead of the previously reported body-centered cubic (BCC) or face-centered-cubic (FCC) types, the major structure was found to show a body-centered tetragonal (BCT) type. The adjacent HDZs are connected by specific junctions, demonstrating that atoms diffuse along some particular high probability paths from one HDZ to another. By considering the three-dimensional liquid density distribution from the continuum point of view, more complete details of the structure and diffusive behavior of liquids in the SLI are also possible to be revealed.
Three-dimensional Kinetic-MHD Model of the Global Heliosphere with the Heliopause-surface Fitting
NASA Astrophysics Data System (ADS)
Izmodenov, V. V.; Alexashov, D. B.
2015-10-01
This paper provides a detailed description of the latest version of our model of the solar wind (SW) interaction with the local interstellar medium (LISM). This model has already been applied to the analysis of Lyα absorption spectra toward nearby stars and for analyses of Solar and Heliospheric Observatory/SWAN data. Katushkina et al. (this issue) used the model results to analyze IBEX-Lo data. At the same time, the details of this model have not yet been published. This is a three-dimensional (3D) kinetic-magnetohydrodynamical (MHD) model that takes into account SW and interstellar plasmas (including α particles in SW and helium ions in LISM), the solar and interstellar magnetic fields, and interstellar hydrogen atoms. The latitudinal dependence of SW and the actual flow direction of the interstellar gas with respect to the Sun are also taken into account in the model. It was very essential that our numerical code was developed in such a way that any numerical diffusion or reconnection across the heliopause were not allowed in the model. The heliospheric current sheet is a rotational discontinuity in the ideal MHD and can be treated kinematically. In the paper, we focus in particular on the effects of the heliospheric magnetic field and on the heliolatitudinal dependence of SW.
Meier, Robert Ch.; Badilita, Vlad; Brunne, Jens; Wallrabe, Ulrike; Korvink, Jan G.
2011-01-01
In this paper we present a new fabrication method that combines for the first time popular SU-8 technology and PerMX dry-photoresist lamination for the manufacturing of high aspect ratio three-dimensional multi-level microfluidic networks. The potential of this approach, which further benefits from wafer-level manufacturing and accurate alignment of fluidic levels, is demonstrated by a highly integrated three-level microfluidic chip. The hereby achieved network complexity, including 24 fluidic vias and 16 crossing points of three individual microchannels on less than 13 mm2 chip area, is unique for SU-8 based fluidic networks. We further report on excellent process compatibility between SU-8 and PerMX dry-photoresist which results in high interlayer adhesion strength. The tight pressure sealing of a fluidic channel (0.5 MPa for 1 h) is demonstrated for 150 μm narrow SU-8/PerMX bonding interfaces. PMID:22662038
Zhou, Song; Li, Feng; Xiao, Jun; Xiong, Wei; Fang, Zhong; Chen, Wenjian; Niu, Pengyan
2010-02-01
The cancer stem cells (CSCs) from human osteosarcoma by serum-free three-dimensional culture combined with anticancer drugs were isolated and identified. The primary cells derived from human osteosarcoma were digested by trypsin to prepare a single-cell suspension, and mixed homogeneously into 1.2% alginate gel. Single-cell alginate gel was cultured with serum-free DMEM/F12 medium. Epirubicin (0.8 microg/mL) was added to the medium to enrich CSCs. After cultured conventionally for 7 to 10 days, most of cells suspended in alginate gel were killed by epirubicin. But few cells survived and some single-cell cloning spheres formed. Immunofluorescent staining for Oct3/4 and Nanog was implemented to find cells with properties of self-renewal and multi-potential differentiation. Cells from cloning spheres were transplanted into BALB/c mice to detect the tumorigenicity in vivo. The results showed that some cells positive for Oct3/4 (TRITC) and Nanog (TRITC) were found in single-cell cloning spheres, and most of positive cells were concentrated in the core of sphere. Cells from spheres could form osteosarcoma in the body of mice. It was concluded that cells from single-cell cloning spheres had the properties of the expression of parts of stem cell genes (Oct3/4 and Nanog), resisting anti-cancer drugs, and tumorigenicity in vivo. To sum up, it is believed that cells obtained from osteosarcoma by serum-free three-dimensional culture combined with anticancer drugs are cancer stem cells. PMID:20155460
1996-01-01
This study provides a three-dimensional (3D) analysis of differences between the 3D morphology of active and inactive human X interphase chromosomes (Xa and Xi territories). Chromosome territories were painted in formaldehyde-fixed, three-dimensionally intact human diploid female amniotic fluid cell nuclei (46, XX) with X-specific whole chromosome compositive probes. The colocalization of a 4,6-diamidino-2- phenylindole dihydrochloride-stained Barr body with one of the two painted X territories allowed the unequivocal discrimination of the inactive X from its active counterpart. Light optical serial sections were obtained with a confocal laser scanning microscope. 3D- reconstructed Xa territories revealed a flatter shape and exhibited a larger and more irregular surface when compared to the apparently smoother surface and rounder shape of Xi territories. The relationship between territory surface and volume was quantified by the determination of a dimensionless roundness factor (RF). RF and surface area measurements showed a highly significant difference between Xa and Xi territories (P < 0.001) in contrast to volume differences (P > 0.1). For comparison with an autosome of similar DNA content, chromosome 7 territories were additionally painted. The 3D morphology of the chromosome 7 territories was similar to the Xa territory but differed strongly from the Xi territory with respect to RF and surface area (P < 0.001). PMID:8978813
NASA Astrophysics Data System (ADS)
Min, Qilong; Gong, Wei; Lin, Bing; Hu, Yongxiang
2015-01-01
This is the second part on assessing the impacts of assimilating various distributions of sea-level pressure (SLP) on hurricane simulations, using the Weather and Research Forecast (WRF) three dimensional variational data assimilation system (3DVAR). One key purpose of this series of study is to explore the potential of using remotely sensed sea surface barometric data from O2-band differential absorption radar system currently under development for server weather including hurricane forecasts. In this part II we further validate the conclusions of observational system simulation experiments (OSSEs) in the part I using observed SLP for three hurricanes that passed over the Florida peninsula. Three SLP patterns are tested again, including all available data near the Florida peninsula, and a band of observations either through the center or tangent to the hurricane position. Before the assimilation, a vortex SLP reconstruction technique is employed for the use of observed SLP as discussed in the part I. In agreement with the results from OSSEs, the performance of assimilating SLP is enhanced for the two hurricanes with stronger initial minimum SLP, leading to a significant improvement in the track and position relative to the control where no data are assimilated. On the other hand, however, the improvement in the hurricane intensity is generally limited to the first 24-48 h of integration, while a high resolution nested domain simulation, along with assimilation of SLP in the coarse domain, shows more profound improvement in the intensity. A diagnostic analysis of the potential vorticity suggests that the improved track forecasts are attributed to the combined effects of adjusting the steering wind fields in a consistent manner with having a deeper vortex, and the associated changes in the convective activity.
NASA Astrophysics Data System (ADS)
Vasilyev, Arseny
This thesis explores the design, construction, and applications of the optoelectronic swept-frequency laser (SFL). The optoelectronic SFL is a feedback loop designed around a swept-frequency (chirped) semiconductor laser (SCL) to control its instantaneous optical frequency, such that the chirp characteristics are determined solely by a reference electronic oscillator. The resultant system generates precisely controlled optical frequency sweeps. In particular, we focus on linear chirps because of their numerous applications. We demonstrate optoelectronic SFLs based on vertical-cavity surface-emitting lasers (VCSELs) and distributed-feedback lasers (DFBs) at wavelengths of 1550 nm and 1060 nm. We develop an iterative bias current predistortion procedure that enables SFL operation at very high chirp rates, up to 1016 Hz/sec. We describe commercialization efforts and implementation of the predistortion algorithm in a stand-alone embedded environment, undertaken as part of our collaboration with Telaris, Inc. We demonstrate frequency-modulated continuous-wave (FMCW) ranging and three-dimensional (3-D) imaging using a 1550 nm optoelectronic SFL. We develop the technique of multiple source FMCW (MS-FMCW) reflectometry, in which the frequency sweeps of multiple SFLs are "stitched" together in order to increase the optical bandwidth, and hence improve the axial resolution, of an FMCW ranging measurement. We demonstrate computer-aided stitching of DFB and VCSEL sweeps at 1550 nm. We also develop and demonstrate hardware stitching, which enables MS-FMCW ranging without additional signal processing. The culmination of this work is the hardware stitching of four VCSELs at 1550 nm for a total optical bandwidth of 2 THz, and a free-space axial resolution of 75 microns. We describe our work on the tomographic imaging camera (TomICam), a 3-D imaging system based on FMCW ranging that features non-mechanical acquisition of transverse pixels. Our approach uses a combination of
Three-dimensional sonoembryology.
Benoit, Bernard; Hafner, Tomislav; Kurjak, Asim; Kupesić, Sanja; Bekavac, Ivanka; Bozek, Tomislav
2002-01-01
Three-dimensional (3D) ultrasound plays an important role in obstetrics, predominantly for assessing fetal anatomy. Presenting volume data in a standard anatomic orientation valuably assists both ultrasonographers and pregnant patients to recognize the anatomy more readily. Three-dimensional ultrasound is advantageous in studying normal embryonic and/or fetal development, as well as providing information for families at risk for specific congenital anomalies by confirming normality. This method offers advantages in assessing the embryo in the first trimester due to its ability to obtain multiplanar images through endovaginal volume acquisition. Rotation allows the systematic review of anatomic structures and early detection of fetal anomalies. Three-dimensional ultrasound imaging in vivo compliments pathologic and histologic evaluation of the developing embryo, giving rise to a new term: 3D sonoembryology. Rapid technological development will allow real-time 3D ultrasound to provide improved and expanded patient care on the one side, and increased knowledge of developmental anatomy on the other. PMID:11933658
Gribenko, Alexey; Mosyak, Lidia; Ghosh, Sharmistha; Parris, Kevin; Svenson, Kristine; Moran, Justin; Chu, Ling; Li, Sheng; Liu, Tong; Woods, Jr., Virgil L.; Jansen, Kathrin U.; Green, Bruce A.; Anderson, Annaliesa S.; Matsuka, Yury V.
2013-08-23
MntC is a metal-binding protein component of the Mn^{2 +}-specific mntABC transporter from the pathogen Staphylococcus aureus. The protein is expressed during the early stages of infection and was proven to be effective at reducing both S. aureus and Staphylococcus epidermidis infections in a murine animal model when used as a vaccine antigen. MntC is currently being tested in human clinical trials as a component of a multiantigen vaccine for the prevention of S. aureus infections. To better understand the biological function of MntC, we are providing structural and biophysical characterization of the protein in this work. The three-dimensional structure of the protein was solved by X-ray crystallography at 2.2 Å resolution and suggests two potential metal binding modes, which may lead to reversible as well as irreversible metal binding. Precise Mn^{2 +}-binding affinity of the protein was determined from the isothermal titration calorimetry experiments using a competition approach. Differential scanning calorimetry experiments confirmed that divalent metals can indeed bind to MntC reversibly as well as irreversibly. Finally, Mn^{2 +}-induced structural and dynamics changes have been characterized using spectroscopic methods and deuterium–hydrogen exchange mass spectroscopy. Results of the experiments show that these changes are minimal and are largely restricted to the structural elements involved in metal coordination. Therefore, it is unlikely that antibody binding to this antigen will be affected by the occupancy of the metal-binding site by Mn^{2 +}.
Yoshimura, S.; Lee, J.S.; Yagawa, G.
1997-02-01
This paper describes a new automated system for analyzing the stress intensity factors (SIFs) of three-dimensional cracks. A geometry model containing one or several three-dimensional cracks is defined using a commercial CAD system, DESIGNBASE. Several local distributions of node density are chosen from the database of the present system, and then automatically superposed on one another over the geometry model by using the fuzzy knowledge processing. Nodes are generated by the bucketing method, and ten-noded quadratic tetrahedral solid elements are generated by the Delaunay method. A user imposes material properties and boundary conditions onto parts of the geometry model such as loops and edges by clicking them with a mouse and by inputting values. For accurate analyses of the stress intensity factors, finer elements are generated in the vicinity of crack tips, thanks to the fuzzy knowledge processing. The singular elements such that the midpoint nodes near crack front are shifted at the quarter-points are automatically placed along the three-dimensional crack front. The complete finite element model generated is given to a commercial finite element code, MARC, and a stress analysis is performed. The stress intensity factors are calculated using the displacement extrapolation method. To demonstrate practical performances of the present system, two dissimilar semi-elliptical surface cracks in a plate subjected to uniform tension are solved, and their interaction effects are discussed in detail. It is shown from the results that ASME Boiler and Pressure Vessel Code, Section 11, Appendix A gives a conservative stress intensity factor for two identical adjacent surface cracks and for two dissimilar adjacent surface cracks.
Winzen, A; Roidl, B; Schröder, W
2016-04-01
Low-speed aerodynamics has gained increasing interest due to its relevance for the design process of small flying air vehicles. These small aircraft operate at similar aerodynamic conditions as, e.g. birds which therefore can serve as role models of how to overcome the well-known problems of low Reynolds number flight. The flight of the barn owl is characterized by a very low flight velocity in conjunction with a low noise emission and a high level of maneuverability at stable flight conditions. To investigate the complex three-dimensional flow field and the corresponding local structural deformation in combination with their influence on the resulting aerodynamic forces, time-resolved stereoscopic particle-image velocimetry and force and moment measurements are performed on a prepared natural barn owl wing. Several spanwise positions are measured via PIV in a range of angles of attack [Formula: see text] 6° and Reynolds numbers 40 000 [Formula: see text] 120 000 based on the chord length. Additionally, the resulting forces and moments are recorded for -10° ≤ α ≤ 15° at the same Reynolds numbers. Depending on the spanwise position, the angle of attack, and the Reynolds number, the flow field on the wing's pressure side is characterized by either a region of flow separation, causing large-scale vortical structures which lead to a time-dependent deflection of the flexible wing structure or wing regions showing no instantaneous deflection but a reduction of the time-averaged mean wing curvature. Based on the force measurements the three-dimensional fluid-structure interaction is assumed to considerably impact the aerodynamic forces acting on the wing leading to a strong mechanical loading of the interface between the wing and body. These time-depending loads which result from the flexibility of the wing should be taken into consideration for the design of future small flying air vehicles using flexible wing structures. PMID:27033298
NASA Astrophysics Data System (ADS)
Aiji, Liang; Chaoyu, Chen; Zhijun, Wang; Youguo, Shi; Ya, Feng; Hemian, Yi; Zhuojin, Xie; Shaolong, He; Junfeng, He; Yingying, Peng; Yan, Liu; Defa, Liu; Cheng, Hu; Lin, Zhao; Guodong, Liu; Xiaoli, Dong; Jun, Zhang; M, Nakatake; H, Iwasawa; K, Shimada; M, Arita; H, Namatame; M, Taniguchi; Zuyan, Xu; Chuangtian, Chen; Hongming, Weng; Xi, Dai; Zhong, Fang; Xing-Jiang, Zhou
2016-07-01
The three-dimensional (3D) Dirac semimetals have linearly dispersive 3D Dirac nodes where the conduction band and valence band are connected. They have isolated 3D Dirac nodes in the whole Brillouin zone and can be viewed as a 3D counterpart of graphene. Recent theoretical calculations and experimental results indicate that the 3D Dirac semimetal state can be realized in a simple stoichiometric compound A 3Bi (A = Na, K, Rb). Here we report comprehensive high-resolution angle-resolved photoemission (ARPES) measurements on the two cleaved surfaces, (001) and (100), of Na3Bi. On the (001) surface, by comparison with theoretical calculations, we provide a proper assignment of the observed bands, and in particular, pinpoint the band that is responsible for the formation of the three-dimensional Dirac cones. We observe clear evidence of 3D Dirac cones in the three-dimensional momentum space by directly measuring on the k x –k y plane and by varying the photon energy to get access to different out-of-plane k z s. In addition, we reveal new features around the Brillouin zone corners that may be related with surface reconstruction. On the (100) surface, our ARPES measurements over a large momentum space raise an issue on the selection of the basic Brillouin zone in the (100) plane. We directly observe two isolated 3D Dirac nodes on the (100) surface. We observe the signature of the Fermi-arc surface states connecting the two 3D Dirac nodes that extend to a binding energy of ∼150 meV before merging into the bulk band. Our observations constitute strong evidence on the existence of the Dirac semimetal state in Na3Bi that are consistent with previous theoretical and experimental work. In addition, our results provide new information to clarify on the nature of the band that forms the 3D Dirac cones, on the possible formation of surface reconstruction of the (001) surface, and on the issue of basic Brillouin zone selection for the (100) surface. Project supported by the
NASA Technical Reports Server (NTRS)
Reddy, C. J.; Deshpande, Manohar D.; Cockrell, C. R.; Beck, F. B.
1995-01-01
A combined finite element method/method of moments (FEM/MoM) approach is used to analyze the electromagnetic scattering properties of a three-dimensional-cavity-backed aperture in an infinite ground plane. The FEM is used to formulate the fields inside the cavity, and the MoM (with subdomain bases) in both spectral and spatial domains is used to formulate the fields above the ground plane. Fields in the aperture and the cavity are solved using a system of equations resulting from the combination of the FEM and the MoM. By virtue of the FEM, this combined approach is applicable to all arbitrarily shaped cavities with inhomogeneous material fillings, and because of the subdomain bases used in the MoM, the apertures can be of any arbitrary shape. This approach leads to a partly sparse and partly full symmetric matrix, which is efficiently solved using a biconjugate gradient algorithm. Numerical results are presented to validate the analysis.
Proctor, Daniel J; Broadfield, Douglas; Proctor, Kristopher
2008-02-01
Multidimensional morphometrics is used to compare the proximal articular surface of the first metatarsal between Homo, Pan, Gorilla, Hylobates, and the hominin fossils A.L. 333-54 (A. afarensis), SKX 5017 (P. robustus), and OH 8 (H. habilis). Statistically significant differences in articular surface morphology exist between H. sapiens and the apes, and between ape groups. Ape groups are characterized by greater surface depth, an obliquely curved articular surface through the dorso-lateral and medio-plantar regions, and a wider medio-lateral surface relative to the dorso-plantar height. The OH 8 articular surface is indistinguishable from H. sapiens, while A.L. 333-54 and SKX 5017 more closely resemble the apes. P. robustus and A. afarensis exhibit ape-like oblique curvature of the articular surface. PMID:18046775
Three-dimensional metamaterials
Burckel, David Bruce
2012-06-12
A fabrication method is capable of creating canonical metamaterial structures arrayed in a three-dimensional geometry. The method uses a membrane suspended over a cavity with predefined pattern as a directional evaporation mask. Metallic and/or dielectric material can be evaporated at high vacuum through the patterned membrane to deposit resonator structures on the interior walls of the cavity, thereby providing a unit cell of micron-scale dimension. The method can produce volumetric metamaterial structures comprising layers of such unit cells of resonator structures.
Sang, Yan-Hui; Hu, Hong-Cheng; Lu, Song-He; Wu, Yu-Wei; Li, Wei-Ran; Tang, Zhi-Hui
2016-01-01
Background: The accuracy of three-dimensional (3D) reconstructions from cone-beam computed tomography (CBCT) has been particularly important in dentistry, which will affect the effectiveness of diagnosis, treatment plan, and outcome in clinical practice. The aims of this study were to assess the linear, volumetric, and geometric accuracy of 3D reconstructions from CBCT and to investigate the influence of voxel size and CBCT system on the reconstructions results. Methods: Fifty teeth from 18 orthodontic patients were assigned to three groups as NewTom VG 0.15 mm group (NewTom VG; voxel size: 0.15 mm; n = 17), NewTom VG 0.30 mm group (NewTom VG; voxel size: 0.30 mm; n = 16), and VATECH DCTPRO 0.30 mm group (VATECH DCTPRO; voxel size: 0.30 mm; n = 17). The 3D reconstruction models of the teeth were segmented from CBCT data manually using Mimics 18.0 (Materialise Dental, Leuven, Belgium), and the extracted teeth were scanned by 3Shape optical scanner (3Shape A/S, Denmark). Linear and volumetric deviations were separately assessed by comparing the length and volume of the 3D reconstruction model with physical measurement by paired t-test. Geometric deviations were assessed by the root mean square value of the imposed 3D reconstruction and optical models by one-sample t-test. To assess the influence of voxel size and CBCT system on 3D reconstruction, analysis of variance (ANOVA) was used (α = 0.05). Results: The linear, volumetric, and geometric deviations were −0.03 ± 0.48 mm, −5.4 ± 2.8%, and 0.117 ± 0.018 mm for NewTom VG 0.15 mm group; −0.45 ± 0.42 mm, −4.5 ± 3.4%, and 0.116 ± 0.014 mm for NewTom VG 0.30 mm group; and −0.93 ± 0.40 mm, −4.8 ± 5.1%, and 0.194 ± 0.117 mm for VATECH DCTPRO 0.30 mm group, respectively. There were statistically significant differences between groups in terms of linear measurement (P < 0.001), but no significant difference in terms of volumetric measurement (P = 0.774). No statistically significant difference were
NASA Astrophysics Data System (ADS)
Kurokawa, Syuhei; Ariura, Yasutsune; Yamamoto, Tatsuyuki
2008-12-01
Leveling of specimen surfaces is very important in measurement of surface roughness. If the surface is not leveled, the measured roughness has large distortion and less vertical measurement range. It is convenient to utilize some automatic leveling procedures instead of manual leveling which needs longer adjustment time. In automatic leveling, a new algorithm is proposed, which is named the spring method superior to the least square method. The spring method has an advantage that a part of tentative data points is used to calculate the surface inclination, so the obtained results are less influenced by local pits for example. As examples, the spring method was applied to actual engineered surfaces, which were milled, shot-peened, and ground surfaces, and also an artificial ditched surface. The results went well for the calculation of the surface inclinations and consequently the specimen surfaces were leveled with less distortion and large vertical measurement range can be achieved. It is also found the least square method is a special case of the spring method with using all sampling data points. That means the spring method is a comprehensive procedure including the least square method. This must become a very strong and robust method in automatic leveling algorithm
Dong, Wenjing; Zhang, Kenan; Zhang, Yun; Wei, Tiaoxing; Sun, Yan; Chen, Xin; Dai, Ning
2014-01-01
We describe a strategy for selectively coating the vertical surfaces of standing nanopillars using area-selective atomic layer deposition (ALD). Hydrophobic self-assembled monolayers (SAMs) are utilised to selectively inhibit the coating of oxides on the modified horizontal regions to ensure that only the vertical surfaces of vertical standing nanorods are coated using ALD processes. This method makes it possible to fabricate vertical nanodevices using a simple process of depositing oxide layer on a vertical surface, and can also be applied to the area-selective surface passivation of other standing structures. PMID:24662775
Crossover between two-dimensional surface state and three-dimensional bulk phase in Fe-doped Bi2Te3
NASA Astrophysics Data System (ADS)
Jo, Na Hyun; Lee, Kyujoon; Kim, Jinsu; Jang, Jungwon; Kim, Jinhee; Jung, Myung-Hwa
2014-06-01
In Fe-doped Bi2Te3, we have observed higher mobility, larger linear magnetoresistance, and anomalous quantum oscillations. The angle dependence of Shubnikov-de Haas (SdH) oscillations gives two different periodicities depending on the angle from the c-axis. The low-angle SdH period is identified with a surface origin, while the high-angle period is against the surface origin. The high-angle SdH period well agrees with the de Haas-van Alphen (dHvA) period with a bulk origin. The physical parameters obtained from the quantum oscillations support the crossover between two-dimensional surface state and three-dimensional bulk phase by Fe doping in Bi2Te3.
Averkov, Yu. O. Prokopenko, Yu. V.; Yakovenko, V. M.
2015-10-15
Electron energy loss by the excitation of surface magnetoplasma oscillations by an electron moving along a static magnetic field in vacuum over a two-dimensional plasma layer on the surface of three-dimensional plasma half-space has been studied theoretically. Electron energy loss by the excitation of surface magnetoplasmons has been calculated in the electrostatic approximation. It has been shown that the type of the dispersion law of electrons in such a plasma (quadratic for a two-dimensional Drude gas or linear for graphene) can be determined from the qualitative character of the dependence of the maximum of the spectral density of this loss on the electron density in the two-dimensional plasma.
Jo, Na Hyun; Lee, Kyujoon; Jung, Myung-Hwa; Kim, Jinsu; Jang, Jungwon; Kim, Jinhee
2014-06-23
In Fe-doped Bi{sub 2}Te{sub 3}, we have observed higher mobility, larger linear magnetoresistance, and anomalous quantum oscillations. The angle dependence of Shubnikov-de Haas (SdH) oscillations gives two different periodicities depending on the angle from the c-axis. The low-angle SdH period is identified with a surface origin, while the high-angle period is against the surface origin. The high-angle SdH period well agrees with the de Haas-van Alphen (dHvA) period with a bulk origin. The physical parameters obtained from the quantum oscillations support the crossover between two-dimensional surface state and three-dimensional bulk phase by Fe doping in Bi{sub 2}Te{sub 3}.
NASA Astrophysics Data System (ADS)
Frantzeskakis, E.; de Jong, N.; Zwartsenberg, B.; Bay, T. V.; Huang, Y. K.; Ramankutty, S. V.; Tytarenko, A.; Wu, D.; Pan, Y.; Hollanders, S.; Radovic, M.; Plumb, N. C.; Xu, N.; Shi, M.; Lupulescu, C.; Arion, T.; Ovsyannikov, R.; Varykhalov, A.; Eberhardt, W.; de Visser, A.; van Heumen, E.; Golden, M. S.
2015-05-01
Topological insulators are a novel materials platform with high applications potential in fields ranging from spintronics to quantum computation. In the ongoing scientific effort to demonstrate controlled manipulation of their electronic structure by external means, i.e., the provision of knobs with which to tune properties, stoichiometric variation and surface decoration are two effective approaches that have been followed. In angle-resolved photoelectron spectroscopy (ARPES) experiments, both approaches are seen to lead to electronic band-structure changes. Most importantly, such approaches result in variations of the energy position of bulk and surface-related features and the creation of two-dimensional electron gases. The data presented here demonstrate that a third manipulation handle is accessible by utilizing the amount of super-band-gap light a topological insulator surface has been exposed to under typical ARPES experimental conditions. Our results show that this third knob acts on an equal footing with stoichiometry and surface decoration as a modifier of the electronic band structure, and that it is in continuous and direct competition with the latter. The data clearly point towards surface photovoltage and photoinduced desorption as the physical phenomena behind modifications of the electronic band structure under exposure to high-flux photons. We show that the interplay of these phenomena can minimize and even eliminate the adsorbate-related surface band bending on typical binary, ternary, and quaternary Bi-based topological insulators. Including the influence of the sample temperature, these data set up a detailed framework for the external control of the electronic band structure in topological insulator compounds in an ARPES setting. Four external knobs are available: bulk stoichiometry, surface decoration, temperature, and photon exposure. These knobs can be used in conjunction to fine tune the band energies near the surface and consequently
Three-dimensional stellarator equilibria by iteration
Boozer, A.H.
1983-02-01
The iterative method of evaluating plasma equilibria is especially simple in a magnetic coordinate representation. This method is particularly useful for clarifying the subtle constraints of three-dimensional equilibria and studying magnetic surface breakup at high plasma beta.
NASA Astrophysics Data System (ADS)
Chambers, J. E.; Wilkinson, P. B.; Penn, S.; Meldrum, P. I.; Kuras, O.; Loke, M. H.; Gunn, D. A.
2013-06-01
We describe the application of 3D electrical resistivity tomography (ERT) to the characterisation and reserve estimation of an economic fluvial sand and gravel deposit. Due to the smoothness constraints used to regularise the inversion, it can be difficult to accurately determine the geometry of sharp interfaces. We have therefore considered two approaches to interface detection that we have applied to the 3D ERT results in an attempt to provide an accurate and objective assessment of the bedrock surface elevation. The first is a gradient-based approach, in which the steepest gradient of the vertical resistivity profile is assumed to correspond to the elevation of the mineral/bedrock interface. The second method uses an intrusive sample point to identify the interface resistivity at a location within the model, from which an iso-resistivity surface is identified that is assumed to define the interface. Validation of these methods has been achieved through direct comparison with observed bedrock surface elevations that were measured using real-time-kinematic GPS subsequent to the 3D ERT survey when quarrying exposed the bedrock surface. The gradient-based edge detector severely underestimated the depth to bedrock in this case, whereas the interface resistivity method produced bedrock surface elevations that were in close agreement with the GPS-derived surface. The failure of the gradient-based method is attributed to insufficient model sensitivity in the region of the bedrock surface, whereas the success of the interface resistivity method is a consequence of the homogeneity of the mineral and bedrock, resulting in a consistent interface resistivity. These results highlight the need for some intrusive data for model validation and for edge detection approaches to be chosen on the basis of local geological conditions.
NASA Astrophysics Data System (ADS)
Fang, Hongjian; Yao, Huajian; Zhang, Haijiang; Huang, Yu-Chih; van der Hilst, Robert D.
2015-06-01
We propose a method to invert surface wave dispersion data directly for 3-D variations of shear wave speed, that is, without the intermediate step of phase or group velocity maps, using frequency-dependent ray tracing and a wavelet-based sparsity-constrained tomographic inversion. A fast marching method is used to compute, at each period, surface wave traveltimes and ray paths between sources and receivers. This avoids the assumption of great-circle propagation that is used in most surface wave tomographic studies, but which is not appropriate in complex media. To simplify the problem we consider quasi-stratified media with smoothly varying seismic properties. We represent the 3-D shear wave speed model by means of 1-D profiles beneath grid points, which are determined from all dispersion data simultaneously using a wavelet-based sparsity-constrained tomographic method. The wavelet coefficients of the wave speed model are estimated with an iteratively reweighted least squares algorithm, and upon iteration the surface wave ray paths and the data sensitivity matrix are updated using the newly obtained wave speed model. To demonstrate its feasibility, we apply the method to determine the 3-D shallow crustal shear wave speed variations in the Taipei basin of Taiwan using short period interstation Rayleigh wave phase velocity dispersion measurements extracted from the ambient noise cross-correlation method. The results are consistent with previous studies and reveal strong shallow crustal heterogeneity that correlates with surface geology.
NASA Astrophysics Data System (ADS)
Fu, Hong; Zheng, Rui; Zheng, Limin
2016-01-01
A new three-dimensional potential energy surface (PES) of the Ne-N2 van der Waals complex was constructed using the neural networks method based on ab initio data points at the CCSD(T) level. The aug-cc-pVQZ basis set was employed for all atoms, supplemented by midbond functions. The vibrationally averaged PES V00 is characterized by a global T-shaped minimum which occurs at R = 3.385 Å, θ = 90.0° with a well depth of -49.202 cm-1. Based on our three-dimensional PES, bound state calculations were performed for four isotopologues, i.e. 20Ne-14N2, 22Ne-14N2, 20Ne-15N2, 22Ne-15N2, and several intermolecular vibrational states were assigned by analyzing the wavefunctions. Moreover, the averaged structural parameters were determined and the pure rotational transition frequencies with J = 0-5 are predicted. The spectroscopic constants were determined by fitting the rotational energy levels. The theoretical results are in good agreement with experimental data and this work gives more accurate results than those determined previously for the Ne-N2 complex.
Seehaus, Frank; Olender, Gavin D; Kaptein, Bart L; Ostermeier, Sven; Hurschler, Christof
2012-05-11
Recent studies have shown that model-based RSA using implant surface models to detect in vivo migration is as accurate as the classical marker-based RSA method. Use of bone surface models would be a further advancement of the model-based method by decreasing complications arising from marker insertion. The aim of this pilot investigation was to assess the feasibility of a "completely markerless" model-based RSA in detecting migration of an implant using bone surface models instead of bone markers. A total knee arthroplasty (TKA) was performed on a human cadaver knee, which was subsequently investigated by repeated RSA measurements performed by one observer. The cadaver knee was CT scanned prior to implantation of the TKA. Tibia-fibular surface models were created using two different commercially available software packages to investigate the effect of segmentation software on the accuracy of repeated migration measures of zero displacement by one observer. Reverse engineered surface models of the TKA tibial component were created. The analysis of the RSA images was repeated 10 times by one individual observer. For the markerless method, the greatest apparent migration observed about the three anatomical axes investigated was between -2.08 and 1.35 mm (SD ≤ 0.88) for z-axis translation, and -4.57° to 7.86° (SD ≤ 3.17) for R(y)-axis rotation, which were well beyond out of the range of what is typically considered adequate for clinically relevant RSA measurements. Use of tibia-fibular surface models of the bone instead of markers could provide practical advantages in evaluating implant migration. However, we found the accuracy and precision of the markerless approach to be lower than that of marker-based RSA, to a degree which precludes the use of this method for measuring implant migration in its present form. PMID:22465625
ERIC Educational Resources Information Center
Shin, Dong Sun; Jang, Hae Gwon; Hwang, Sung Bae; Har, Dong-Hwan; Moon, Young Lae; Chung, Min Suk
2013-01-01
In the Visible Korean project, serially sectioned images of the pelvis were made from a female cadaver. Outlines of significant structures in the sectioned images were drawn and stacked to build surface models. To improve the accessibility and informational content of these data, a five-step process was designed and implemented. First, 154 pelvic…
Grad, Sibylle; Lee, Cynthia R; Gorna, Katarzyna; Gogolewski, Sylwester; Wimmer, Markus A; Alini, Mauro
2005-01-01
A cartilage engineering bioreactor has been developed that provides joint-specific kinematics. This study investigated the effect of articular motion on the gene expression of superficial zone protein (SZP) and hyaluronan synthases (HASs) and on the release of SZP and hyaluronan of chondrocytes seeded onto biodegradable scaffolds. Cylindrical (8 x 4 mm) porous polyurethane scaffolds were seeded with bovine articular chondrocytes and subjected to static or dynamic compression, with and without articulation against a ceramic hip ball. After loading, the mRNA expression of SZP and HASs was analyzed, and SZP immunoreactivity and hyaluronan concentration of conditioned media were determined. Surface motion significantly upregulated the mRNA expression of SZP and HASs. Axial compression alone had no effect on SZP and increased HAS mRNA only at high strain amplitude. SZP was immunodetected only in the media of constructs exposed to surface motion. The release of hyaluronan into the culture medium was significantly enhanced by surface motion. These results indicate that specific stimuli that mimic the kinematics of natural joints, such as articular motion, may promote the development of a functional articular surface-synovial interface. PMID:15738679
Kasson, Peter M.; Hess, Berk; Lindahl, Erik
2013-01-01
Cellular lipid membranes are spatially inhomogeneous soft materials. Materials properties such as pressure and surface tension thus show important microscopic-scale variation that is critical to many biological functions. We present a means to calculate pressure and surface tension in a 3D-resolved manner within molecular-dynamics simulations and show how such measurements can yield important insight. We also present the first corrections to local virial and pressure fields to account for the constraints typically used in lipid simulations that otherwise cause problems in highly oriented systems such as bilayers. Based on simulations of an asymmetric bacterial ion channel in a POPC bilayer, we demonstrate how 3D-resolved pressure can probe for both short-range and long-range effects from the protein on the membrane environment. We also show how surface tension is a sensitive metric for inter-leaflet equilibrium and can be used to detect even subtle imbalances between bilayer leaflets in a membrane-protein simulation. Since surface tension is known to modulate the function of many proteins, this effect is an important consideration for predictions of ion channel function. We outline a strategy by which our local pressure measurements, which we make available within a version of the GROMACS simulation package, may be used to design optimally equilibrated membrane-protein simulations. PMID:23318532
Johnson, Timothy C.; Slater, Lee; Ntarlagiannis, Dimitrios; Day-Lewis, Frederick D.; Elwaseif, Mehrez
2012-08-22
Time-lapse resistivity imaging is increasingly used to monitor hydrologic processes. Compared to conventional hydrologic measurements, surface time-lapse resistivity provides (1) superior spatial coverage in two or three dimensions, (2) potentially high-resolution information in time, and (3) information in the absence of wells. However, interpretation of time-lapse electrical tomograms is complicated by the ever increasing size and complexity of long-term, three-dimensional time-series conductivity datasets. Here, we use three-dimensional (3D) surface time-lapse electrical imaging to monitor subsurface electrical conductivity variations associated with stage-driven groundwater/surface-water interaction along a stretch of the Columbia River adjacent to the Hanford 300 Area, Hanford WA, USA. We reduce the resulting 3D conductivity time series using both correlation and time-frequency analysis to isolate a paleochannel causing enhanced groundwater/river-water interaction. Correlation analysis on the time-lapse imaging results concisely represents enhanced ground water/surface-water interaction within the paleochannel, and provides information concerning groundwater flow velocities. Time-frequency analysis using the Stockwell (S) Transform provides additional information by 1) identifying the stage periodicities driving ground water/river-water interaction due to upstream dam operations, 2) identifying segments in time-frequency space when these interactions are most active. These results provide new insight into the distribution and timing of river water intrusion into the Hanford 300 area, which has a governing influence on the behavior of a uranium plume left over from historical nuclear fuel processing operations.
NASA Astrophysics Data System (ADS)
Ma, Conghui; Wen, Gongjian; Ding, Boyuan; Zhong, JinRong; Yang, Xiaoliang
2016-01-01
A three-dimensional electromagnetic model (3-D EM-model)-based scattering center matching method is developed for synthetic aperture radar automatic target recognition (ATR). 3-D EM-model provides a concise and physically relevant description of the target's electromagnetic scattering phenomenon through its scattering centers which makes it an ideal candidate for ATR. In our method, scatters of the 3-D EM-model are projected to the two-dimensional measurement plane to predict scatters' location and scattering intensity properties. Then the identical information is extracted for scatters in measured data. A two-stage iterative operation is applied to match the model-predicted scatters and the measured data-extracted scatters by combining spatial and attributed information. Based on the two scatter sets' matching information, a similarity measurement between model and measured data is obtained and recognition conclusion is made. Meanwhile, the target's configuration is reasoned with 3-D EM-model serving as a reference. In the end, data simulated by electromagnetic computation verified this method's validity.
NASA Astrophysics Data System (ADS)
Cedola, Alessia; Campi, Gaetano; Pelliccia, Daniele; Bukreeva, Inna; Fratini, Michela; Burghammer, Manfred; Rigon, Luigi; Arfelli, Fulvia; Chen, Rong Chang; Dreossi, Diego; Sodini, Nicola; Mohammadi, Sara; Tromba, Giuliana; Cancedda, Ranieri; Mastrogiacomo, Maddalena
2014-01-01
Computed x-ray phase contrast micro-tomography is the most valuable tool for a three dimensional (3D) and non destructive analysis of the tissue engineered bone morphology. We used a Talbot interferometer installed at SYRMEP beamline of the ELETTRA synchrotron (Trieste, Italy) for a precise 3D reconstruction of both bone and soft connective tissue, regenerated in vivo within a porous scaffold. For the first time the x-ray tomographic reconstructions have been combined with x-ray scanning micro-diffraction measurement on the same sample, in order to give an exhaustive identification of the different tissues participating to the biomineralization process. As a result, we were able to investigate in detail the different densities in the tissues, distinguishing the 3D organization of the amorphous calcium phosphate from the collagen matrix. Our experimental approach allows for a deeper understanding of the role of collagen matrix in the organic-mineral transition, which is a crucial issue for the development of new bio-inspired composites.
Wüst, Silke; Godla, Marie E; Müller, Ralph; Hofmann, Sandra
2014-02-01
Three-dimensional (3-D) bioprinting is the layer-by-layer deposition of biological material with the aim of achieving stable 3-D constructs for application in tissue engineering. It is a powerful tool for the spatially directed placement of multiple materials and/or cells within the 3-D sample. Encapsulated cells are protected by the bioink during the printing process. Very few materials are available that fulfill requirements for bioprinting as well as provide adequate properties for cell encapsulation during and after the printing process. A hydrogel composite including alginate and gelatin precursors was tuned with different concentrations of hydroxyapatite (HA) and characterized in terms of rheology, swelling behavior and mechanical properties to assess the versatility of the system. Instantaneous as well as long-term structural integrity of the printed hydrogel was achieved with a two-step mechanism combining the thermosensitive properties of gelatin with chemical crosslinking of alginate. Novel syringe tip heaters were developed for improved temperature control of the bioink to avoid clogging. Human mesenchymal stem cells mixed into the hydrogel precursor survived the printing process and showed high cell viability of 85% living cells after 3 days of subsequent in vitro culture. HA enabled the visualization of the printed structures with micro-computed tomography. The inclusion of HA also favors the use of the bioink for bone tissue engineering applications. By adding factors other than HA, the composite could be used as a bioink for applications in drug delivery, microsphere deposition or soft tissue engineering. PMID:24157694
Cedola, Alessia; Campi, Gaetano; Pelliccia, Daniele; Bukreeva, Inna; Fratini, Michela; Burghammer, Manfred; Rigon, Luigi; Arfelli, Fulvia; Chang Chen, Rong; Dreossi, Diego; Sodini, Nicola; Mohammadi, Sara; Tromba, Giuliana; Cancedda, Ranieri; Mastrogiacomo, Maddalena
2014-01-01
Computed x-ray phase contrast micro-tomography is the most valuable tool for a three dimensional (3D) and non destructive analysis of the tissue engineered bone morphology. We used a Talbot interferometer installed at SYRMEP beamline of the ELETTRA synchrotron (Trieste, Italy) for a precise 3D reconstruction of both bone and soft connective tissue, regenerated in vivo within a porous scaffold. For the first time the x-ray tomographic reconstructions have been combined with x-ray scanning micro-diffraction measurement on the same sample, in order to give an exhaustive identification of the different tissues participating to the biomineralization process. As a result, we were able to investigate in detail the different densities in the tissues, distinguishing the 3D organization of the amorphous calcium phosphate from the collagen matrix. Our experimental approach allows for a deeper understanding of the role of collagen matrix in the organic-mineral transition, which is a crucial issue for the development of new bio-inspired composites. PMID:24334371
Liu, Chun-Yen; Matsusaki, Michiya; Akashi, Mitsuru
2016-04-01
Living tissues or organ modules consist of different types of highly organized cells and extracellular matrices (ECMs) in a hierarchical manner, such as the multilayered structure of blood vessels and the radial structures of hepatic lobules. Due to animal examinations being banned in the EU since 2013 and a shortage in the demand for tissue repair or organ transplantation, the creation of artificial 3D tissues possessing specific structures and functions similar to natural tissues are key challenges in tissue engineering. To date, we have developed a simple but unique bottom-up approach, a hierarchical cell manipulation technique, with a nanometer-sized ECM matrix consisting of fibronectin (FN) and gelatin (G) on cell surfaces. About 10 nm thick FN/G ECM films on cell surfaces were coated successfully by using layer-by-layer coating methodology. Various 3D constructs with higher cell density with different types of cells were successfully constructed. In addition to the construction of tissues with higher cell densities, other tissues, such as cartilage or skin tissues, with different cell densities are also important tissue models for tissue engineering and pharmaceutical industries. Thus, we recently developed other methodologies, the collagen coating method and multiple coating method, to fabricate micrometer-sized level ECM layers on cell surfaces. Various micro- or millimeter-sized 3D constructs with lower cell densities were constructed successfully. By using these two methods, cell distances in 2D or 3D views can be controlled by different thicknesses of ECM layers on cell surfaces at the single-cell level. Both FN/G and the collagen coating method resulted in homogenous 3D tissues with a controlled layer numbers, cell type, cell location, and properties; these will be promising to achieve different goals in tissue engineering. PMID:26924465
NASA Astrophysics Data System (ADS)
Huang, Yongjie; Cui, Xiaopeng; Li, Xiaofan
2016-03-01
Based on the governing equations for water species in the Weather Research and Forecasting (WRF) model, a three-dimensional WRF-based surface precipitation equation was obtained and applied to investigate the surface rainfall processes of a torrential rain event. Sensitivity experiments were performed to further explore roles of surface evaporation in the heavy rainfall event. The results show that the contributions of moisture-related processes to precipitation (QWV, including water vapor local change (QWVL), surface evaporation (QWVE), moisture advection (QWVA), and so on) dominate the torrential rain event, while the contributions of cloud-related processes (QCM) also play indispensable roles whose maximum net contributions could exceed 20%. QWVA dominates the budget of water vapor, while QWVL and QWVE play smaller but by no means negligible roles in the event. Sensitivity experiments show that the changes of surface evaporation affect both moisture-related processes and cloud-related processes, and then influence the intensity and regional redistribution of precipitation. Surface evaporation favors the accumulation of convective available potential energy and enhances the instability of atmosphere, being prone to the development of convective systems. Meanwhile, it also affects the development of vertical motions and cloud systems. Thus accurate estimation of surface evaporation is necessary for accurate simulation and forecast of surface precipitation.
Yao, Manwen; Wu, Yichuan; Fang, Xiangyi; Yang, Yucong; Liu, Hongjun
2015-04-15
A method of immobilizing clenbuterol (CLEN) on the sensor chip for spectral surface plasmon resonance imaging (SPRi) was experimentally investigated. The bioprobes on the sensor chip were prepared by immobilizing bovine serum albumin (BSA) protein and conjugating CLEN molecules to BSA, which provides more active points and free orientations for specific binding. The calibration curve showed that the wavelength resonance shift decreased as the concentration of CLEN analyte increased, consistent with the inhibition principle. The limit of detection (LOD) was estimated to be 6.32 μg/ml. This method proved to be highly specific, high throughput, label free, and operationally convenient. PMID:25637304
Three-Dimensional Surface Geophysical Exploration of the 200-Series Tanks at the 241-C Tank Farm
Crook, N.; McNeill, M.; Dunham, Ralph; Glaser, Danney R.
2014-02-26
A surface geophysical exploration (SGE) survey using direct current electrical resistivity was conducted within the C Tank Farm in the vicinity of the 200-Series tanks at the Hanford Site near Richland, Washington. This survey was the second successful SGE survey to utilize the Geotection(TM)-180 Resistivity Monitoring System which facilitated a much larger survey size and faster data acquisition rate. The primary objective of the C Tank Farm SGE survey was to provide geophysical data and subsurface imaging results to support the Phase 2 RCRA Facility Investigation, as outlined in the Phase 2 RCRA Facility Investigation / Corrective Measures work plan RPP-PLAN-39114.
NASA Astrophysics Data System (ADS)
Lauer, Eric A.; Corner, Brian D.; Li, Peng; Beecher, Robert M.; Deutsch, Curtis
2002-03-01
Traditionally, medical geneticists have employed visual inspection (anthroposcopy) to clinically evaluate dysmorphology. In the last 20 years, there has been an increasing trend towards quantitative assessment to render diagnosis of anomalies more objective and reliable. These methods have focused on direct anthropometry, using a combination of classical physical anthropology tools and new instruments tailor-made to describe craniofacial morphometry. These methods are painstaking and require that the patient remain still for extended periods of time. Most recently, semiautomated techniques (e.g., structured light scanning) have been developed to capture the geometry of the face in a matter of seconds. In this paper, we establish that direct anthropometry and structured light scanning yield reliable measurements, with remarkably high levels of inter-rater and intra-rater reliability, as well as validity (contrasting the two methods).
NASA Astrophysics Data System (ADS)
Durganandini, P.
2016-03-01
We study theoretically, the electromagnetic response due to localized charge current distributions above a topological insulator (coated with a thin ferromagnetic layer) using the electromagnetic SL(2,Z) duality symmetry. We show that the localized current induces an electric field which depends on the current —this is a manifestation of the topological magnetoelectric (TME) effect. We also show that if the charge carriers have spin, then they acquire Aharanov-Casher phases which depend on the current. As an application, we consider thin planar charged quantum rings with persistent currents on the surface of a TI and show that the TME manifests itself as persistent Hall voltages across the charged ring. If the spin is also taken into account, then persistent spin Hall voltages develop across the ring.
NASA Technical Reports Server (NTRS)
Maskew, B.
1983-01-01
A general low-order surface-singularity panel method is used to predict the aerodynamic characteristics of a problem where a wing-tip vortex from one wing closely interacts with an aft mounted wing in a low Reynolds Number flow; i.e., 125,000. Nonlinear effects due to wake roll-up and the influence of the wings on the vortex path are included in the calculation by using a coupled iterative wake relaxation scheme. The interaction also affects the wing pressures and boundary layer characteristics: these effects are also considered using coupled integral boundary layer codes and preliminary calculations using free vortex sheet separation modelling are included. Calculated results are compared with water tunnel experimental data with generally remarkably good agreement.
NASA Astrophysics Data System (ADS)
Weidman, P. D.; Ishak, Anuar
2015-08-01
New solutions of flow induced by a biorthogonally stretching surface are reported. The flexible membrane has linear stretching rate a along the x-axis and b along the y-axis. A similarity reduction of the Navier-Stokes equations yields a coupled pair of ordinary differential equations governed the single parameter α = b / a . Dual solutions are found in the region αt < α ⩽ 1 , where αt = - 0.2514 . One of the two components of the dual solutions exhibits algebraic decay in the far field. It appears that no self-similar solutions exist for α <αt . It is also shown that the exact solution for flow induced by a unilaterally stretching sheet due to Crane has dual solutions with algebraic decay in the far field.
Phan-Quang, Gia Chuong; Lee, Hiang Kwee; Phang, In Yee; Ling, Xing Yi
2015-08-10
Colloidosomes are robust microcapsules attractive for molecular sensing because of their characteristic micron size, large specific surface area, and dual-phase stability. However, current colloidosome sensors are limited to qualitative fluorogenic receptor-based detection, which restrict their applicability to a narrow range of molecules. Here, we introduce plasmonic colloidosome constructed from Ag nanocubes as an emulsion-based 3D SERS platform. The colloidosomes exhibit excellent mechanical robustness, flexible size tunability, versatility to merge, and ultrasensitivity in SERS quantitation of food/industrial toxins down to sub-femtomole levels. Using just 0.5 μL of sample volumes, our plasmonic colloidosomes exhibit >3000-fold higher SERS sensitivity over conventional suspension platform. Notably, we demonstrate the first high-throughput multiplex molecular sensing across multiple liquid phases. PMID:26120021
NASA Astrophysics Data System (ADS)
Marone, Federica; Gung, Yuancheng; Romanowicz, Barbara
2007-10-01
Seismic anisotropy provides insight into palaeo and recent deformation processes and, therefore, mantle dynamics. In a first step towards a model for the North American upper mantle with anisotropy characterized by a symmetry axis of arbitrary orientation, aimed at filling the gap between global tomography and SKS splitting studies, we inverted long period waveform data simultaneously for perturbations in the isotropic S-velocity structure and the anisotropic parameter , in the framework of normal mode asymptotic coupling theory (NACT). The resulting 2-D broad-band sensitivity kernels allow us to exploit the information contained in long period seismograms for fundamental and higher mode surface waves at the same time. To ensure high quality of the retrieved regional upper-mantle structure, accurate crustal corrections are essential. Here, we follow an approach which goes beyond the linear perturbation approximation and split the correction into a linear and non-linear part. The inverted data set consists of more than 40000 high quality three component fundamental and overtone surface waveforms, recorded at broad-band seismic stations in North America from teleseismic events and provides a fairly homogeneous path and azimuthal coverage. The isotropic part of our tomographic model shares the large-scale features of previous regional studies for North America. We confirm the pronounced difference in the isotropic velocity structure between the western active tectonic region and the central/eastern stable shield, as well as the presence of subducted material (Juan de Fuca and Farallon Plate) at transition zone depths. The new regional 3-D radial anisotropic model indicates the presence of two distinct anisotropic layers beneath the cratonic part of the North American continent: a deep asthenospheric layer, consistent with present day mantle flow, and a shallower lithospheric layer, possibly a record of ancient tectonic events.
Wang, Ruozheng; Yin, Yong; Qin, Yonghui; Yu, Jinming
2015-12-01
The purpose of this study was to evaluate the feasibility and benefits of using high-dose-rate three-dimensional conformal radiotherapy (3D-CRT) combined with active breathing control (ABC) for stereotactic body radiotherapy (SBRT) of patients with early-stage non-small-cell lung cancer (NSCLC). Eight patients with early-stage NSCLC underwent CT scans under standard free-breathing (FB) and moderately deep inspiration breath-hold (mDIBH) with ABC. Two high-dose-rate 3D-CRT plans (1000 Mu/min) were designed based on the CT scans with FB and mDIBH. The maximal dose (D1%), minimal dose (D99%), conformity index (CI), and homogeneity index (HI) of the planning target volume (PTV), and dose-volume indices of the organs at risk between each plan were compared. The mean PTV volume decreased from 158.04 cm(3) with FB to 76.90 cm(3) with mDIBH (p < 0.05). When mDIBH was used, increases in the affected lung volume (by 47%), contralateral lung volume (by 55%), and total lung volume (by 50%) were observed compared to FB (p < 0.05). The V5-V40 of the affected lung (Vx represented the percentage volume of organs receiving at least the x Gy), V5-V40 and the mean dose for the total lung, V5-V40 and mean dose of the chest wall, and the maximum dose of the spinal cord were less for mDIBH than FB (p < 0.05). There were no significant differences in CI, HI, D1%, or D99% for the PTV between the plans. In conclusion, high-dose-rate 3D-CRT combined with ABC reduced the radiation dose to the lungs and chest wall without affecting the dose distribution in SBRT of early-stage NSCLC patients. PMID:24988055
Ozaki, Hiroya; Tominaga, Jun-ya; Hamanaka, Ryo; Sumi, Mayumi; Chiang, Pao-Chang; Tanaka, Motohiro; Koga, Yoshiyuki
2015-01-01
The porpose of this study was to determine the optimal length of power arms for achieving controlled anterior tooth movement in segmented arch mechanics combined with power arm. A three-dimensional finite element method was applied for the simulation of en masse anterior tooth retraction in segmented power arm mechanics. The type of tooth movement, namely, the location of center of rotation of the maxillary central incisor in association with power arm length, was calculated after the retraction force was applied. When a 0.017 × 0.022-in archwire was inserted into the 0.018-in slot bracket, bodily movement was obtained at 9.1 mm length of power arm, namely, at the level of 1.8 mm above the center of resistance. In case a 0.018 × 0.025-in full-size archwire was used, bodily movement of the tooth was produced at the power arm length of 7.0 mm, namely, at the level of 0.3 mm below the center of resistance. Segmented arch mechanics required shorter length of power arms for achieving any type of controlled anterior tooth movement as compared to sliding mechanics. Therefore, this space closing mechanics could be widely applied even for the patients whose gingivobuccal fold is shallow. The segmented arch mechanics combined with power arm could provide higher amount of moment-to-force ratio sufficient for controlled anterior tooth movement without generating friction, and vertical forces when applying retraction force parallel to the occlusal plane. It is, therefore, considered that the segmented power arm mechanics has a simple appliance design and allows more efficient and controllable tooth movement. PMID:25610497
NASA Astrophysics Data System (ADS)
Sun, Mengwei; Xu, Zhen; Yin, Min; Lin, Qingfeng; Lu, Linfeng; Xue, Xinzhong; Zhu, Xufei; Cui, Yanxia; Fan, Zhiyong; Ding, Yiling; Tian, Li; Wang, Hui; Chen, Xiaoyuan; Li, Dongdong
2016-04-01
ZnO semiconductor films with periodic 3D nanocave patterns were fabricated by the thermal nanoimprinting technology, which is promising for photodetectors with enhanced light harvesting capability. The Au nanoparticles were further introduced into the ZnO films, which boosts the UV response of ZnO films and extends the photodetection to visible regions. The best UV photoresponse was detected on the 3D nanocave ZnO-Au hybrid films, attributing to the light trapping mechanism of 3D periodic structures and the driving force of the Schottky barrier at the ZnO/Au interface, while the high visible photoresponse of ZnO-Au hybrid films mainly results from the hot electron generation and injection process over the Schottky junctions mediated by Au surface plasmon resonances. The work provides a cost-effective pathway to develop large-scale periodic 3D nanopatterned thin film photodetectors and is promising for the future deployment of high performance optoelectronic devices.ZnO semiconductor films with periodic 3D nanocave patterns were fabricated by the thermal nanoimprinting technology, which is promising for photodetectors with enhanced light harvesting capability. The Au nanoparticles were further introduced into the ZnO films, which boosts the UV response of ZnO films and extends the photodetection to visible regions. The best UV photoresponse was detected on the 3D nanocave ZnO-Au hybrid films, attributing to the light trapping mechanism of 3D periodic structures and the driving force of the Schottky barrier at the ZnO/Au interface, while the high visible photoresponse of ZnO-Au hybrid films mainly results from the hot electron generation and injection process over the Schottky junctions mediated by Au surface plasmon resonances. The work provides a cost-effective pathway to develop large-scale periodic 3D nanopatterned thin film photodetectors and is promising for the future deployment of high performance optoelectronic devices. Electronic supplementary information
Three-Dimensional Cu2ZnSnS4 Films with Modified Surface for Thin-Film Lithium-Ion Batteries.
Lin, Jie; Guo, Jianlai; Liu, Chang; Guo, Hang
2015-08-12
Cu2ZnSnS4 (CZTS) is an important material in low-cost thin film solar cells and is also a promising candidate for lithium storage. In this work, a novel three-dimensional CZTS film coated with a lithium phosphorus oxynitride (LiPON) film is fabricated for the first time and is applied to thin-film lithium-ion batteries. The modified film exhibits an excellent performance of ∼900 mAh g(-1) (450 μAh cm(-2) μm(-1)), even after 75 cycles. Morphology integrity is still maintained after repeated lithiation/delithiation, and the main reaction mechanism is analyzed in detail. The significant findings from this study indicate the striking advantages of modifying both the surface and structure of alloy-based electrodes for energy storage. PMID:26192026
Hayat, Tasawar; Aziz, Arsalan; Muhammad, Taseer; Ahmad, Bashir
2015-01-01
This article investigates the magnetohydrodynamic (MHD) three-dimensional flow of couple stress nanofluid subject to the convective boundary condition. Flow is generated due to a nonlinear stretching of the surface in two lateral directions. Temperature and nanoparticles concentration distributions are studied through the Brownian motion and thermophoresis effects. Couple stress fluid is considered electrically conducting through a non-uniform applied magnetic field. Mathematical formulation is developed via boundary layer approach. Nonlinear ordinary differential systems are constructed by employing suitable transformations. The resulting systems have been solved for the convergent series solutions of velocities, temperature and nanoparticles concentration profiles. Graphs are sketched to see the effects of different interesting flow parameters on the temperature and nanoparticles concentration distributions. Numerical values are computed to analyze the values of skin-friction coefficients and Nusselt number. PMID:26714259
Hayat, Tasawar; Aziz, Arsalan; Muhammad, Taseer; Ahmad, Bashir
2015-01-01
This article investigates the magnetohydrodynamic (MHD) three-dimensional flow of couple stress nanofluid subject to the convective boundary condition. Flow is generated due to a nonlinear stretching of the surface in two lateral directions. Temperature and nanoparticles concentration distributions are studied through the Brownian motion and thermophoresis effects. Couple stress fluid is considered electrically conducting through a non-uniform applied magnetic field. Mathematical formulation is developed via boundary layer approach. Nonlinear ordinary differential systems are constructed by employing suitable transformations. The resulting systems have been solved for the convergent series solutions of velocities, temperature and nanoparticles concentration profiles. Graphs are sketched to see the effects of different interesting flow parameters on the temperature and nanoparticles concentration distributions. Numerical values are computed to analyze the values of skin-friction coefficients and Nusselt number. PMID:26714259
Sun, Mengwei; Xu, Zhen; Yin, Min; Lin, Qingfeng; Lu, Linfeng; Xue, Xinzhong; Zhu, Xufei; Cui, Yanxia; Fan, Zhiyong; Ding, Yiling; Tian, Li; Wang, Hui; Chen, Xiaoyuan; Li, Dongdong
2016-04-28
ZnO semiconductor films with periodic 3D nanocave patterns were fabricated by the thermal nanoimprinting technology, which is promising for photodetectors with enhanced light harvesting capability. The Au nanoparticles were further introduced into the ZnO films, which boosts the UV response of ZnO films and extends the photodetection to visible regions. The best UV photoresponse was detected on the 3D nanocave ZnO-Au hybrid films, attributing to the light trapping mechanism of 3D periodic structures and the driving force of the Schottky barrier at the ZnO/Au interface, while the high visible photoresponse of ZnO-Au hybrid films mainly results from the hot electron generation and injection process over the Schottky junctions mediated by Au surface plasmon resonances. The work provides a cost-effective pathway to develop large-scale periodic 3D nanopatterned thin film photodetectors and is promising for the future deployment of high performance optoelectronic devices. PMID:27073045
NASA Astrophysics Data System (ADS)
Wang, Zhenzhou
2016-08-01
In this paper, we present a 3D surface imaging system based on the well-known phase shift profilometry. To yield the analytical solutions, four shifted phases and three high carrier frequencies are used to compute the phase map and reduce the noises that are caused by the inherent optical aberrations and external influences, e.g. different illumination light sources, uneven intensity distribution and automatic image processing algorithms. To reduce the system noise, we propose to model the pattern of the calibration grid in a virtual space. To obtain the modeled pattern, we use a plane to intercept the rays that are modeled by the proposed angle modeling method. In the world coordinate system, the angle and the pattern are computed based on the calibration data. A registration method is used to transform the modeled pattern in the virtual space to the ideal pattern in the world coordinate system by computing the least squared errors between the true points in the modeled pattern and the measured points in the practical pattern. The modeled (true) points are used for re-calibration of the 3D imaging system. Experimental results showed that the measurement accuracy increases considerably and the MSE is reduced from 0.95 mm to 0.65 mm (32% average error decrease) after replacing the measured points with the true points for calibration.
NASA Astrophysics Data System (ADS)
Stephen, R. A.; Udovydchenkov, I. A.; Bolmer, T.; Komatitsch, D.; Tromp, J.; Casarotti, E.; Xie, Z.; Worcester, P. F.
2015-12-01
Bottom-diffracted surface-reflected (BDSR) arrivals were first identified in the 2004 Long-range Ocean Acoustic Propagation Experiment (Stephen et al, 2013, JASA, v.134, p.3307-3317). The BDSR mechanism provides a means for acoustic signals and noise from distant sources to appear with significant strength on the deep seafloor. At depths greater than the conjugate depth ambient noise and PE- predicted arrivals are sufficiently quiet that BDSR paths, scattered from small seamounts, can be the largest amplitude arrivals observed. The Ocean Bottom Seismometer Augmentation in the North Pacific (OBSANP) Experiment in June-July 2013 was designed to further define the characteristics of the BDSRs and to understand the conditions under which BDSRs are excited and propagate. An example of BDSR arrivals is shown on the record section in the figure. Other arrivals are the direct water wave and first and second multiples. The reciprocal of the BDSR mechanism also plays a role in T-phase excitation. To further understand the BDSR mechanism, the SPECFEM3D code was extended to handle high-frequency, deep water bottom scattering problems with actual bathymetry and a typical sound speed profile in the water column. The model size is 38km x 27km x 6.5km. The source is centered at 10Hz with a 5Hz bandwidth. Work supported by NSF and ONR.
NASA Technical Reports Server (NTRS)
Roth, Don J.; Kautz, Harold E.; Abel, Phillip B.; Whalen, Mike F.; Hendricks, J. Lynne; Bodis, James R.
2000-01-01
Surface topography, which significantly affects the performance of many industrial components, is normally measured with diamond-tip profilometry over small areas or with optical scattering methods over larger areas. To develop air-coupled surface profilometry, the NASA Glenn Research Center at Lewis Field initiated a Space Act Agreement with Sonix, Inc., through two Glenn programs, the Advanced High Temperature Engine Materials Program (HITEMP) and COMMTECH. The work resulted in quantitative surface topography profiles obtained using only high-frequency, focused ultrasonic pulses in air. The method is nondestructive, noninvasive, and noncontact, and it does not require light-reflective surfaces. Air surface profiling may be desirable when diamond-tip or laserbased methods are impractical, such as over large areas, when a significant depth range is required, or for curved surfaces. When the configuration is optimized, the method is reasonably rapid and all the quantitative analysis facilities are online, including two- and three-dimensional visualization, extreme value filtering (for faulty data), and leveling.
Three-dimensional coherent structures of electrokinetic instability
NASA Astrophysics Data System (ADS)
Demekhin, E. A.; Nikitin, N. V.; Shelistov, V. S.
2014-07-01
A direct numerical simulation of the three-dimensional elektrokinetic instability near a charge-selective surface (electric membrane, electrode, or system of micro- or nanochannels) has been carried out and analyzed. A special finite-difference method has been used for the space discretization along with a semi-implicit 31/3-step Runge-Kutta scheme for the integration in time. The calculations employ parallel computing. Three characteristic patterns, which correspond to the overlimiting currents, are observed: (a) two-dimensional electroconvective rolls, (b) three-dimensional regular hexagonal structures, and (c) three-dimensional structures of spatiotemporal chaos, which are a combination of unsteady hexagons, quadrangles, and triangles. The transition from (b) to (c) is accompanied by the generation of interacting two-dimensional solitary pulses.
Three-dimensional coherent structures of electrokinetic instability.
Demekhin, E A; Nikitin, N V; Shelistov, V S
2014-07-01
A direct numerical simulation of the three-dimensional elektrokinetic instability near a charge-selective surface (electric membrane, electrode, or system of micro- or nanochannels) has been carried out and analyzed. A special finite-difference method has been used for the space discretization along with a semi-implicit 31/3-step Runge-Kutta scheme for the integration in time. The calculations employ parallel computing. Three characteristic patterns, which correspond to the overlimiting currents, are observed: (a) two-dimensional electroconvective rolls, (b) three-dimensional regular hexagonal structures, and (c) three-dimensional structures of spatiotemporal chaos, which are a combination of unsteady hexagons, quadrangles, and triangles. The transition from (b) to (c) is accompanied by the generation of interacting two-dimensional solitary pulses. PMID:25122393
Bai, Houqiao; Gao, Peng; Gao, Hao; Sun, Guangxi; Dong, Chonghai; Han, Jian; Jiang, Guosheng
2016-01-01
BACKGROUND Transarterial chemoembolization (TACE) has been used alone or in combination with three-dimensional conformal radiation therapy (3DCRT) for treating hepatocellular carcinoma (HCC). The overall survival rate of HCC patients undergoing both treatments, however, has not been systematically studied. The aim of this meta-analysis-based study was to evaluate the overall efficacy of the combined therapy or monotherapy, thereby providing information for clinical treatment. MATERIAL AND METHODS We searched Google Scholar, PubMed, and Chinese National Knowledge Infrastructure (CNKI) for eligible studies, and a total of 17 case-control studies (including HCC patients treated by TACE plus 3DCRT or TACE alone) were included to perform the meta-analysis. Based on the available data, we assessed the improvements of 1-year, 2-year, and 3-year survival rate for the combination therapy of TACE and 3DCRT or TACE alone. Furthermore, the analysis was also stratified by the tumor response: complete response (CR), partial response (PR), no response (NR) and progressive disease (PD). Statistical analysis was performed using STATA 12 (Stata Statistical Software: Release 12). RESULTS The results show that HCC patients receiving combination therapy have significantly increased overall survival rate when compared to those receiving TACE alone (1-year survival rate: OR=1.95, 95% CI 1.54-2.47, p=7.3×10^-8; 2-year survival rate: OR=1.87, 95% CI 1.49-2.34, p=1.6×10^-7; 3-year survival rate: OR=2.00, 95% CI 1.52-2.64, p=1.8×10^-6). CONCLUSIONS Assessment of tumor response demonstrates that the combination therapy can efficiently increase the tumor response rate (CR+PR: OR=2.29, 95% CI 1.70-3.08, p=1.1×10^-7), with a lower rate of subsequent tumor development (PD: OR=0.25, 95% CI 0.15-0.40, p=5.5×10^-8). PMID:27228411
Brugger, Nicolas; Wustmann, Kerstin; Hürzeler, Michael; Wahl, Andreas; de Marchi, Stefano F; Steck, Hélène; Zürcher, Fabian; Seiler, Christian
2015-04-15
The aim of our study was to evaluate 3-dimensional (3D) color Doppler proximal isovelocity surface area (PISA) as a tool for quantitative assessment of mitral regurgitation (MR) against in vitro and in vivo reference methods. A customized 3D PISA software was validated in vitro against a flowmeter MR phantom. Sixty consecutive patients, with ≥mild MR of any cause, were recruited and the regurgitant volume (RVol) was measured by 2D PISA, 3D peak PISA, and 3D integrated PISA, using transthoracic (TTE) and transesophageal echocardiography (TEE). Cardiac magnetic resonance imaging (CMR) was used as reference method. Flowmeter RVol was associated with 3D integrated PISA as follows: y = 0.64x + 4.7, r(2) = 0.97, p <0.0001 for TEE and y = 0.88x + 4.07, r(2) = 0.96, p <0.0001 for TTE. The bias and limit of agreement in the Bland-Altman analysis were 6.8 ml [-3.5 to 17.1] for TEE and -0.059 ml [-6.2 to 6.1] for TTE. In vivo, TEE-derived 3D integrated PISA was the most accurate method for MR quantification compared to CMR: r(2) = 0.76, y = 0.95x - 3.95, p <0.0001; 5.1 ml (-14.7 to 26.5). It was superior to TEE 3D peak PISA (r(2) = 0.67, y = 1.00x + 6.20, p <0.0001; -6.3 ml [-33.4 to 21.0]), TEE 2D PISA (r(2) = 0.54, y = 0.76x + 0.18, p <0.0001; 8.4 ml [-20.4 to 37.2]), and TTE-derived measurements. It was also most accurate by receiver operating characteristic analysis (area under the curve 0.99) for the detection of severe MR, RVol cutoff = 48 ml, sensibility 100%, and specificity 96%. RVol and the cutoff to define severe MR were underestimated using the most accurate method. In conclusion, quantitative 3D color Doppler echocardiography of the PISA permits a more accurate MR assessment than conventional techniques and, consequently, should enable an optimized management of patients suffering from MR. PMID:25747111
Sharp, R.V.; Saxton, J.L.
1989-01-01
Seven quadrilaterals, constructed at broadly distributed points on surface breaks within the Superstition Hills fault zone, were repeatedly remeasured after the pair of 24 November 1987 earthquakes to monitor the growing surface displacement. Changes in the dimensions of the quadrilaterals are recalculated to right-lateral and extensional components at millimeter resolution, and vertical components of change are resolved at 0.2mm precision. The displacement component data for four of the seven quadrilaterals record the complete fault movement with respect to an October 1986 base. The three-dimensional motion vectors all describe nearly linear trajectories throughout the observation period, and they indicate smooth shearing on their respective fault surfaces. The inclination of the shear surfaces is generally nearly vertical, except near the south end of the Superstition Hills fault zone where two strands dip northeastward at about 70??. Surface displacement on these strands is right reverse. Another kind of deformation, superimposed on the fault displacements, has been recorded at all quadrilateral sites. It consists of a northwest-southeast contraction or component of contraction that ranged from 0 to 0.1% of the quadrilateral lengths between November 1987 and April 1988. -from Authors
Forsythe, Kevin; Blacksburg, Seth; Stone, Nelson; Stock, Richard G.
2012-06-01
Purpose: To measure the benefits of intensity-modulated radiotherapy (IMRT) compared with three-dimensional conformal radiotherapy (3D-CRT) when used in combination with brachytherapy for the treatment of prostate cancer. Methods and Materials: We conducted a retrospective review of all patients with localized prostate cancer who received external-beam radiotherapy (EBRT) in combination with brachytherapy with at least 1 year follow-up (n = 812). Combination therapy consisted of {sup 103}Pd or {sup 125}I implant, followed by a course of EBRT. From 1993 to March 2003 521 patients were treated with 3D-CRT, and from April 2003 to March 2009 291 patients were treated with IMRT. Urinary symptoms were prospectively measured with the International Prostate Symptom Score questionnaire with a single quality of life (QOL) question; rectal bleeding was assessed per the Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer Late Radiation Morbidity Scoring Schema. The Pearson {chi}{sup 2} test was used to compare toxicities experienced by patients who were treated with either IMRT or 3D-CRT. Logistic regression analyses were also performed to rule out possible confounding factors. Results: Within the first 3 months after treatment, patients treated with 3D-CRT scored their urinary symptoms as follows: 19% mild, 44% moderate, and 37% severe; patients treated with IMRT scored their urinary symptoms as follows: 36% mild, 47% moderate, and 17% severe (p < 0.001). The 3D-CRT patients rated their QOL as follows: 35% positive, 20% neutral, and 45% negative; IMRT patients rated their QOL as follows: 51% positive, 18% neutral, and 31% negative (p < 0.001). After 1 year of follow-up there was no longer any difference in urinary morbidity between the two groups. Logistic regression confirmed the differences in International Prostate Symptom Score and QOL in the acute setting (p < 0.001 for both). Grade {>=}2 rectal bleeding was reported by 11% of 3D
NASA Astrophysics Data System (ADS)
Hayashida, Takumi; Tajima, Fumiko; Nakajima, Junichi; Mori, Jim
2012-11-01
Recent three-dimensional (3-D) travel-time tomographic models of southwestern (SW) Japan image the subducting Philippine Sea plate (PHSP) and low velocity anomalies with long-wavelength spatial resolution. However, the agreement between the synthetics calculated with the existing 3-D model and data is not satisfactory forsP and S waves in the higher frequency range (≥0.2 Hz). The unsatisfactory agreement can be attributed to the parameters of the initial wave speed model for the tomographic inversion, as well as the difficulty in detecting S-wave travel times accurately. In order to improve the wave speed model, we first constructed a 3-D reference model by forward modeling using waveform data from an intraslab earthquake and then performed repeated travel-time inversions using the 3-D reference model as the initial model. The newly derived high-resolution model 3DM_SWJ can produce synthetics that are substantially in better agreement with the data than previous models. The distribution of highP-wave toS-wave speed ratios (VP/VS) calculated from model 3DM_SWJ shows short-wavelength heterogeneities that could have been formed in relation to the subduction of the Philippine Sea Plate beneath the Eurasian plate. This combined use of forward waveform modeling for slab and crust configuration and repeated tomographic inversion of travel-times provides a better 3-D structural model of seismic properties for understanding tectonic features related to the subduction process, in addition to better estimating ground motions.
NASA Astrophysics Data System (ADS)
Dighe, Manish Deepak
2000-10-01
7XXX series wrought aluminum alloys are extensively used for structural aerospace applications due to their high strength to weight ratio, excellent corrosion resistance, and high fracture resistance. 7050 is an important alloy of this group, which is widely used for the applications such as aircraft wing skin structures, aircraft landing gear parts, and fuselage frame structure. Therefore, it is of interest to investigate the fracture behavior of 7050 aluminum alloy, which is a typical alloy of 7XXX series. The aim of this research is to quantitatively characterize and model the relationships among processing, microstructure, fracture surface morphology, and fracture toughness of hot-rolled partially recrystallized precipitation hardened 7050 alloy. A new technique is developed which permits simultaneous viewing of the fracture surface and the microstructure just below and above the fracture surface. This technique is then applied to identify, validate and quantify various fracture micro-mechanisms observed on the fracture surface. To get a better insight in to the shape and anisotropy of the recrystallized grains, the three-dimensional structure of the microstructure is reconstructed using serial sectioning. The gathered information is utilized to develop a mathematical model relating the various processing parameters and microstructural attributes to the fracture toughness.
NASA Astrophysics Data System (ADS)
Li, Bin; Han, Ke-Li
2008-03-01
A theoretical investigation on the nonadiabatic processes of the full three-dimensional D++H2 and H++D2 reaction systems has been performed by using trajectory surface hopping (TSH) method based on the Zhu-Nakamura (ZN) theory. This ZN-TSH method refers to not only classically allowed hops but also classically forbidden hops. The potential energy surface constructed by Kamisaka et al. is employed in the calculation. A new iterative method is proposed to yield the two-dimensional seam surface from the topography of the adiabatic potential surfaces, in which the inconvenience of directly solving the first-order partial differential equation is avoided. The cross sections of these two systems are calculated for three competing channels of the reactive charge transfer, the nonreactive charge transfer, and the reactive noncharge transfer, for ground rovibrational state of H2 or D2. Also, this study provides reaction probabilities of these three processes for the total angular momentum J =0 and ground initial vibrational state of H2 or D2. The calculated results from ZN-TSH method are in good agreement with the exact quantum calculations and the experimental measurements.
NASA Astrophysics Data System (ADS)
Ahmed, Raheel; Edwards, Michael G.; Lamine, Sadok; Huisman, Bastiaan A. H.; Pal, Mayur
2015-12-01
A novel cell-centred control-volume distributed multi-point flux approximation (CVD-MPFA) finite-volume formulation is presented for discrete fracture-matrix simulations on unstructured grids in three-dimensions (3D). The grid is aligned with fractures and barriers which are then modelled as lower-dimensional surface interfaces located between the matrix cells in the physical domain. The three-dimensional pressure equation is solved in the matrix domain coupled with a two-dimensional (2D) surface pressure equation solved over fracture networks via a novel surface CVD-MPFA formulation. The CVD-MPFA formulation naturally handles fractures with anisotropic permeabilities on unstructured grids. Matrix-fracture fluxes are expressed in terms of matrix and fracture pressures and define the transfer function, which is added to the lower-dimensional flow equation and couples the three-dimensional and surface systems. An additional transmission condition is used between matrix cells adjacent to low permeable fractures to couple the velocity and pressure jump across the fractures. Convergence and accuracy of the lower-dimensional fracture model is assessed for highly anisotropic fractures having a range of apertures and permeability tensors. A transport equation for tracer flow is coupled via the Darcy flux for single and intersecting fractures. The lower-dimensional approximation for intersecting fractures avoids the more restrictive CFL condition corresponding to the equi-dimensional approximation with explicit time discretisation. Lower-dimensional fracture model results are compared with equi-dimensional model results. Fractures and barriers are efficiently modelled by lower-dimensional interfaces which yield comparable results to those of the equi-dimensional model. Pressure continuity is built into the model across highly conductive fractures, leading to reduced local degrees of freedom in the CVD-MPFA approximation. The formulation is applied to geologically complex
Kosmoliaptsis, Vasilis; Dafforn, Timothy R; Chaudhry, Afzal N; Halsall, David J; Bradley, J Andrew; Taylor, Craig J
2011-11-01
The potential of human leukocyte antigens (HLA) to stimulate humoral alloimmunity depends on the orientation, accessibility and physiochemical properties of polymorphic amino acids. We have generated high-resolution structural and physiochemical models of all common HLA class I alleles and analyzed the impact of amino acid polymorphisms on surface electrostatic potential. Atomic resolution three-dimensional structural models of HLA class I molecules were generated using the MODELLER computer algorithm. The molecular surface electrostatic potential was calculated using the DelPhi program. To confirm that electrostatic surface topography reflects known HLA B cell epitopes, we examined Bw4 and Bw6 and ascertained the impact of amino acid polymorphisms on their tertiary and physiochemical composition. The HLA protein structures generated performed well when subjected to stereochemical and energy-based testing for structural integrity. The electrostatic pattern and conformation of Bw4 and Bw6 epitopes are maintained among HLA molecules even when expressed in a different structural context. Importantly, variation in epitope amino acid composition does not always translate into a different electrostatic motif, providing an explanation for serologic cross-reactivity. Mutations of critical amino acids that abrogate antibody binding also induce distinct changes in epitope electrostatic properties. In conclusion, high-resolution structural modeling provides a physiochemical explanation for serologic patterns of antibody binding and provides novel insights into HLA immunogenicity. PMID:21840357
Johnson, Timothy C.; Slater, Lee D.; Ntarlagiannis, Dimitris; Day-Lewis, Frederick D.; Elwaseif, Mehrez
2012-01-01
Time-lapse resistivity imaging is increasingly used to monitor hydrologic processes. Compared to conventional hydrologic measurements, surface time-lapse resistivity provides superior spatial coverage in two or three dimensions, potentially high-resolution information in time, and information in the absence of wells. However, interpretation of time-lapse electrical tomograms is complicated by the ever-increasing size and complexity of long-term, three-dimensional (3-D) time series conductivity data sets. Here we use 3-D surface time-lapse electrical imaging to monitor subsurface electrical conductivity variations associated with stage-driven groundwater-surface water interactions along a stretch of the Columbia River adjacent to the Hanford 300 near Richland, Washington, USA. We reduce the resulting 3-D conductivity time series using both time-series and time-frequency analyses to isolate a paleochannel causing enhanced groundwater-surface water interactions. Correlation analysis on the time-lapse imaging results concisely represents enhanced groundwater-surface water interactions within the paleochannel, and provides information concerning groundwater flow velocities. Time-frequency analysis using the Stockwell (S) transform provides additional information by identifying the stage periodicities driving groundwater-surface water interactions due to upstream dam operations, and identifying segments in time-frequency space when these interactions are most active. These results provide new insight into the distribution and timing of river water intrusion into the Hanford 300 Area, which has a governing influence on the behavior of a uranium plume left over from historical nuclear fuel processing operations.
Fierke, Melissa A.; Lai, Chun-Ze; Bühlmann, Philippe; Stein, Andreas
2009-01-01
The effects of the architecture and surface chemistry of three-dimensionally ordered macroporous (3DOM) carbon solid contacts on the properties of ion-selective electrodes (ISEs) were examined. Infiltration of the plasticized PVC membrane into the pores of the carbon created a large interfacial area between the sensing membrane and the solid contact, as shown by cryo-SEM and elemental analysis. This large interfacial area, along with the high capacitance of the 3DOM carbon solid contacts (as determined by cyclic voltammetry, chronopotentiometry, and electrochemical impedance spectroscopy) results in an excellent long-term stability of the potentiometric response, with drifts as low as 11.7 µV/h. The comparison of 3DOM carbon solid contacts with an untemplated carbon solid contact shows that the pore structure is an essential feature for the excellent electrode performance. However, the surface chemistry of the 3DOM carbon cannot be ignored. While there is no evidence for an aqueous layer forming between the sensing membrane and unoxidized 3DOM carbon, electrodes based on oxidized 3DOM carbon exhibit potentiometric responses with the typical hysteresis indicative of a water layer. A comparison of the different techniques to characterize the solid contacts confirms that constant-current charge-discharge experiments offer an intriguing approach to assess the long-term stability of solid-contact ISEs but shows that their results need to be interpreted with care. PMID:20000696
NASA Astrophysics Data System (ADS)
Ajili, Y.; Ben Abdallah, D.; Mogren Al-Mogren, M.; Lique, F.; Francisco, J. S.; Hochlaf, M.
2016-07-01
The intermonomer three-dimensional potential-energy surface (3D PES) of the thiazyl-hydride-helium (HSN-He) weakly bound molecular system is generated using the explicitly correlated coupled-cluster method with single, double, and perturbative triple excitations. The 3D PES is mapped in Jacobi coordinates. This potential-energy surface shows a unique potential well at planar configurations. The depth of this potential is 74.4 c m-1 . This 3D PES is incorporated into a close-coupling and coupled-states quantum dynamical treatment of nuclear motions to deduce the rotational (de-)excitation of HSN by He for energies up to 1400 c m-1 . After averaging over a Maxwell-Boltzmann distribution, the collisional rate coefficients are derived for temperatures ranging from 5 to 200 K. These data are essential for the identification of HSN molecules in astrophysical media. A comparison between thionitrosyl-hydride—He and HSN-He is performed.
NASA Astrophysics Data System (ADS)
Miyata, Tatsuhiko; Ikuta, Yasuhiro; Hirata, Fumio
2010-07-01
This article proposes a free energy calculation method based on the molecular dynamics simulation combined with the three dimensional reference interaction site model theory. This study employs the free energy perturbation (FEP) and the thermodynamic integration (TDI) along the coupling parameters to control the interaction potential. To illustrate the method, we applied it to a complex formation process in aqueous solutions between a crown ether molecule 18-Crown-6 (18C6) and a potassium ion as one of the simplest model systems. Two coupling parameters were introduced to switch the Lennard-Jones potential and the Coulomb potential separately. We tested two coupling procedures: one is a "sequential-coupling" to couple the Lennard-Jones interaction followed by the Coulomb coupling, and the other is a "mixed-coupling" to couple both the Lennard-Jones and the Coulomb interactions together as much as possible. The sequential-coupling both for FEP and TDI turned out to be accurate and easily handled since it was numerically well-behaved. Furthermore, it was found that the sequential-coupling had relatively small statistical errors. TDI along the mixed-coupling integral path was to be carried out carefully, paying attention to a numerical behavior of the integrand. The present model system exhibited a nonmonotonic behavior in the integrands for TDI along the mixed-coupling integral path and also showed a relatively large statistical error. A coincidence within a statistical error was obtained among the results of the free energy differences evaluated by FEP, TDI with the sequential-coupling, and TDI with the mixed-coupling. The last one is most attractive in terms of the computer power and is accurate enough if one uses a proper set of windows, taking the numerical behavior of the integrands into account. TDI along the sequential-coupling integral path would be the most convenient among the methods we tested, since it seemed to be well-balanced between the computational
Johnson, D N; Pedit, J A; Miller, C T
2004-10-01
Remediation of porous media containing an entrapped dense nonaqueous phase liquid (DNAPL) is extremely difficult due to the heterogeneity and three-dimensional spatial nature of typical natural systems. A novel treatment technology based on surfactant- and gravity-induced mobilization, dense brine containment and collection, and a vapor-phase extraction polishing step is proposed as a means to remediate such systems. Laboratory experiments are performed using the suggested methodology applied to three-dimensional, heterogeneous systems, which are packed based upon a realization from a correlated random field. Entrapped DNAPL is effectively removed as a result of each component of the technology. Following vapor extraction, less than 1% of the original DNAPL mass remained in the system. While these results are very promising, several open issues must be resolved before this technology can be considered mature; both the investigation of some of these issues and a summary of remaining needs are addressed. PMID:15506211
Li, Ming; Cushing, Scott K.; Zhang, Jianming; Suri, Savan; Evans, Rebecca; Petros, William P.; Gibson, Laura F.; Ma, Dongling; Liu, Yuxin; Wu, Nianqiang
2013-01-01
A three-dimensional (3D) hierarchical plasmonic nano-architecture has been designed for a sensitive surface-enhanced Raman scattering (SERS) immuno-sensor for protein biomarker detection. The capture antibody molecules are immobilized on a plasmonic gold triangle nano-array pattern. On the other hand, the detection antibody molecules are linked to the gold nano-star@Raman-reporter@silica sandwich nanoparticles. When protein biomarkers are present, the sandwich nanoparticles are captured over the gold triangle nano-array, forming a confined 3D plasmonic field, leading to the enhanced electromagnetic field in intensity and in 3D space. As a result, the Raman reporter molecules are exposed to a high density of “hot spots”, which amplifies the Raman signal remarkably, improving the sensitivity of the SERS immuno-sensor. This SERS immuno-sensor exhibits a wide linear range (0.1 pg/mL to 10 ng/mL), and a low limit of detection (7 fg/mL) toward human immunoglobulin G (IgG) protein in the buffer solution. This biosensor has been successfully used for detection of the vascular endothelial growth factor (VEGF) in the human blood plasma from clinical breast cancer patient samples. PMID:23659430
Hayat, T.; Muhammad, Taseer; Shehzad, S. A.; Alsaedi, A.
2015-01-15
Development of human society greatly depends upon solar energy. Heat, electricity and water from nature can be obtained through solar power. Sustainable energy generation at present is a critical issue in human society development. Solar energy is regarded one of the best sources of renewable energy. Hence the purpose of present study is to construct a model for radiative effects in three-dimensional of nanofluid. Flow of second grade fluid by an exponentially stretching surface is considered. Thermophoresis and Brownian motion effects are taken into account in presence of heat source/sink and chemical reaction. Results are derived for the dimensionless velocities, temperature and concentration. Graphs are plotted to examine the impacts of physical parameters on the temperature and concentration. Numerical computations are presented to examine the values of skin-friction coefficients, Nusselt and Sherwood numbers. It is observed that the values of skin-friction coefficients are more for larger values of second grade parameter. Moreover the radiative effects on the temperature and concentration are quite reverse.
NASA Astrophysics Data System (ADS)
Li, Dongshuai; Zhang, Qilin; Liu, Tao; Wang, Zhenhui
2013-11-01
this paper, we have extended the Cooray-Rubinstein (C-R) approximate formula into the fractal rough ground surface and then validate its accuracy by using three-dimensional (3-D) finite-difference time-domain (FDTD) method at distances of 50 m and 100 m from the lightning channel. The results show that the extended C-R formula has an accepted accuracy for predicting the lightning-radiated horizontal electric field above the fractal rough and conducting ground, and its accuracy increases a little better with the higher of the earth conductivity. For instance, when the conductivity of the rough ground is 0.1 S/m, the error of the peak value predicted by the extended C-R formula is less than about 2.3%, while its error is less than about 6.7% for the conductivity of 0.01 S/m. The rough ground has much effect on the lightning horizontal field, and the initial peak value of the horizontal field obviously decreases with the increase of the root-mean-square height of the rough ground at early times (within several microseconds of the beginning of return stroke).
NASA Astrophysics Data System (ADS)
Okimura, Takashi
1994-05-01
A three-dimensional multi-planar sliding surface method developed from the two-dimensional method is proposed to identify the shape and/or volume of a shallow failure that appears on a mountain slope during heavy rainfall. The method is constructed to satisfy the equilibrium of forces in the cross-sectional and longitudinal directions on an assumed sliding mass that is regarded as being rectangular in plan shape. It was applied to a digital elevation model to determine the site and form of a critical sliding mass on a mountain slope. Calculations made with a testing model of a simple planar slope show that the safety factor calculated using this method is similar to factots obtained by the 3D Hovland and 3D simplified Janbu methods. The method was applied to an actual mountain slope on which a shallow failure caused by heavy rainfall took place. The most probable unstable mass calculated by the model was almost the same as that at the failed site. The method proposed can be used to predict a potentially unstable mass that leads to shallow failure.
Joseph, Jesuchristopher; Warton, Christopher; Jacobson, Sandra W; Jacobson, Joseph L; Molteno, Chris D; Eicher, Anton; Marais, Patrick; Phillips, Owen R; Narr, Katherine L; Meintjes, Ernesta M
2014-02-01
Surface deformation-based analysis was used to assess local shape variations in the hippocampi and caudate nuclei of children with fetal alcohol spectrum disorders. High-resolution structural magnetic resonance imaging images were acquired for 31 children (19 controls and 12 children diagnosed with fetal alcohol syndrome/partial FAS). Hippocampi and caudate nuclei were manually segmented, and surface meshes were reconstructed. An iterative closest point algorithm was used to register the template of one control subject to all other shapes in order to capture the true geometry of the shape with a fixed number of landmark points. A point distribution model was used to quantify the shape variations in terms of a change in co-ordinate positions. Using the localized Hotelling T(2) method, regions of significant shape variations between the control and exposed subjects were identified and mapped onto the mean shapes. Binary masks of hippocampi and caudate nuclei were generated from the segmented volumes of each brain. These were used to compute the volumes and for further statistical analysis. The Mann-Whitney test was performed to predict volume differences between the groups. Although the exposed and control subjects did not differ significantly in their volumes, the shape analysis showed the hippocampus to be more deformed at the head and tail regions in the alcohol-exposed children. Between-group differences in caudate nucleus morphology were dispersed across the tail and head regions. Correlation analysis showed associations between the degree of compression and the level of alcohol exposure. These findings demonstrate that shape analysis using three-dimensional surface measures is sensitive to fetal alcohol exposure and provides additional information than volumetric measures alone. PMID:23124690
NASA Technical Reports Server (NTRS)
Lynch, Gillian C.; Halvick, Philippe; Zhao, Meishan; Truhlar, Donald G.; Yu, Chin-Hui; Kouri, Donald J.; Schwenke, David W.
1991-01-01
Accurate three-dimensional quantum mechanical reaction probabilities are presented for the reaction F + H2 yields HF + H on the new global potential energy surface 5SEC for total angular momentum J = 0 over a range of translational energies from 0.15 to 4.6 kcal/mol. It is found that the v-prime = 3 HF vibrational product state has a threshold as low as for v-prime = 2.
Han, Zhenzhen; Liu, Honglin; Wang, Bin; Weng, Shizhuang; Yang, Liangbao; Liu, Jinhuai
2015-01-01
Rapid component separation and robust surface-enhanced Raman scattering (SERS) identification of drugs in real human urine remain an attractive challenge because of the sample complexity, low molecular affinity for metal surface, and inefficient use of hotspots in one- or two-dimensional (2D) geometries. Here, we developed a 5 min strategy of cyclohexane (CYH) extraction for separating amphetamines from human urine. Simultaneously, an oil-in-water emulsion method is used to assemble monodisperse Ag nanoparticles in the CYH phase into spherical colloidal superstructures in the aqueous phase. These superstructures create three-dimensional (3D) SERS hotspots which exist between every two adjacent particles in 3D space, break the traditional 2D limitation, and extend the hotspots into the third dimension along the z-axis. In this platform, a conservative estimate of Raman enhancement factor is larger than 10(7), and the same CYH extraction processing results in a high acceptability and enrichment of drug molecules in 3D hotspots which demonstrates excellent stability and reproducibility and is suitable for the quantitative examination of amphetamines in both aqueous and organic phases. Parallel ultraperformance liquid chromatography (UPLC) examinations corroborate an excellent performance of our SERS platform for the quantitative analysis of methamphetamine (MA) in both aqueous solution and real human urine, of which the detection limits reach 1 and 10 ppb, respectively, with tolerable signal-to-noise ratios. Moreover, SERS examinations on different proportions of MA and 3,4-methylenedioxymethamphetamine (MDMA) in human urine demonstrate an excellent capability of multiplex quantification of ultratrace analytes. By virtue of a spectral classification algorithm, we realize the rapid and accurate recognition of weak Raman signals of amphetamines at trace levels and also clearly distinguish various proportions of multiplex components. Our platform for detecting drugs
NASA Astrophysics Data System (ADS)
Zhang, Hai-Feng; Liu, Shao-Bin; Tang, Yi-Jun
2014-06-01
In this paper, the properties of the extraordinary mode and surface plasmon modes in the three-dimensional (3D) magnetized plasma photonic crystals (MPPCs) with face-centered-cubic lattices that are composed of the core tellurium (Te) spheres with surrounded by the homogeneous magnetized plasma shells inserted in the air, are theoretically investigated in detail by the plane wave expansion method, as the magneto-optical Voigt effects of magnetized plasma are considered (the incidence electromagnetic wave vector is perpendicular to the external magnetic field at any time). The optical switching or wavelength division multiplexer can be realized by the proposed 3D MPPCs. Our analyses demonstrate that the complete photonic band gaps (PBGs) and two flatbands regions for the extraordinary mode can be observed obviously. PBGs can be tuned by the radius of core Te sphere, the plasma density and the external magnetic field. The flatbands regions are determined by the existence of surface plasmon modes. Numerical simulations also show that if the thickness of magnetized plasma shell is larger than a threshold value, the band structures of the extraordinary mode will be similar to those obtained from the same structure containing the pure magnetized plasma spheres. In this case, the band structures also will not be affected by the inserted core spheres. It is also provided that the upper edges of two flatbands regions will not depend on the topology of lattice. However, the frequencies of lower edges of two flatbands regions will be convergent to the different constants for different lattices, as the thickness of magnetized plasma shell is close to zero.
Zhang, Hai-Feng E-mail: lsb@nuaa.edu.cn; Liu, Shao-Bin E-mail: lsb@nuaa.edu.cn; Tang, Yi-Jun
2014-06-15
In this paper, the properties of the extraordinary mode and surface plasmon modes in the three-dimensional (3D) magnetized plasma photonic crystals (MPPCs) with face-centered-cubic lattices that are composed of the core tellurium (Te) spheres with surrounded by the homogeneous magnetized plasma shells inserted in the air, are theoretically investigated in detail by the plane wave expansion method, as the magneto-optical Voigt effects of magnetized plasma are considered (the incidence electromagnetic wave vector is perpendicular to the external magnetic field at any time). The optical switching or wavelength division multiplexer can be realized by the proposed 3D MPPCs. Our analyses demonstrate that the complete photonic band gaps (PBGs) and two flatbands regions for the extraordinary mode can be observed obviously. PBGs can be tuned by the radius of core Te sphere, the plasma density and the external magnetic field. The flatbands regions are determined by the existence of surface plasmon modes. Numerical simulations also show that if the thickness of magnetized plasma shell is larger than a threshold value, the band structures of the extraordinary mode will be similar to those obtained from the same structure containing the pure magnetized plasma spheres. In this case, the band structures also will not be affected by the inserted core spheres. It is also provided that the upper edges of two flatbands regions will not depend on the topology of lattice. However, the frequencies of lower edges of two flatbands regions will be convergent to the different constants for different lattices, as the thickness of magnetized plasma shell is close to zero.
NASA Astrophysics Data System (ADS)
Zhang, H.; Thurber, C. H.; Maceira, M.; Roux, P.
2013-12-01
The crust around the San Andreas Fault Observatory at depth (SAFOD) has been the subject of many geophysical studies aimed at characterizing in detail the fault zone structure and elucidating the lithologies and physical properties of the surrounding rocks. Seismic methods in particular have revealed the complex two-dimensional (2D) and three-dimensional (3D) structure of the crustal volume around SAFOD and the strong velocity reduction in the fault damage zone. In this study we conduct a joint inversion using body-wave arrival times and surface-wave dispersion data to image the P-and S-wave velocity structure of the upper crust surrounding SAFOD. The two data types have complementary strengths - the body-wave data have good resolution at depth, albeit only where there are crossing rays between sources and receivers, whereas the surface waves have very good near-surface resolution and are not dependent on the earthquake source distribution because they are derived from ambient noise. The body-wave data are from local earthquakes and explosions, comprising the dataset analyzed by Zhang et al. (2009). The surface-wave data are for Love waves from ambient noise correlations, and are from Roux et al. (2011). The joint inversion code is based on the regional-scale version of the double-difference (DD) tomography algorithm tomoDD. The surface-wave inversion code that is integrated into the joint inversion algorithm is from Maceira and Ammon (2009). The propagator matrix solver in the algorithm DISPER80 (Saito, 1988) is used for the forward calculation of dispersion curves from layered velocity models. We examined how the structural models vary as we vary the relative weighting of the fit to the two data sets and in comparison to the previous separate inversion results. The joint inversion with the 'optimal' weighting shows more clearly the U-shaped local structure from the Buzzard Canyon Fault on the west side of SAF to the Gold Hill Fault on the east side.
Three Dimensional Numerical Analysis on Discharge Properties
NASA Astrophysics Data System (ADS)
Takaishi, Kenji; Katsurai, Makoto
2003-10-01
A three dimensional simulation code with the finite difference time domain (FDTD) method combined with the two fluids model for electron and ion has been developed for the microwave excited surface wave plasma in the RDL-SWP device. This code permits the numerical analysis of the spatial distributions of electric field, power absorption, electron density and electron temperature. At low gas pressure of about 10 mTorr, the numerical results compared with the experimental measurements that shows the validity of this 3-D simulation code. A simplified analysis assuming that an electron density is spatially uniform has been studied and its applicability is evaluated by 3-D simulation. The surface wave eigenmodes are determined by electron density, and it is found that the structure of the device strongly influences to the spatial distribution of the electric fields of surface wave in a low density area. A method to irradiate a microwave to the whole surface area of the plasma is proposed which is found to be effective to obtain a high uniformity distribution of electron density.
Han, Chengzong; Liu, Zhongming; Zhang, Xin; Pogwizd, Steven; He, Bin
2009-01-01
Three-dimensional (3-D) cardiac activation imaging (3-DCAI) is a recently developed technique that aims at imaging the activation sequence throughout the 3-D volume of myocardium. 3-DCAI entails the modeling and estimation of the cardiac equivalent current density (ECD) distribution from which the local activation time within myocardium is determined as the time point with the peak amplitude of local ECD estimates. In this paper, we report, for the first time, an experimental study of the performance and applicability of 3-DCAI as judged by measured 3-D cardiac activation sequence using 3-D intra-cardiac mapping, in a group of 4 healthy rabbits during ventricular pacing. During the experiments, the body surface potentials and the intramural bipolar electrical recordings were simultaneously measured in a closed-chest condition to allow for a rigorous evaluation of the noninvasive 3-DCAI algorithm using the intra-cardiac mapping. The ventricular activation sequence non-invasively imaged from the body surface measurements by using 3-DCAI was generally in agreement with that obtained from the invasive intra-cardiac recordings. The overall difference between them, quantified as the root mean square (RMS) error, was 7.42±0.61 ms, and the normalized difference, quantified as the relative error (RE), was 0.24±0.03. The distance from the reconstructed site of initial activation to the actual pacing site, defined as the localization error (LE), was 5.47±1.57 mm. In addition, computer simulations were conducted to provide additional assessment of the performance of the 3-DCAI algorithm using a realistic-geometry rabbit heart-torso model. Averaged over 9 pacing sites, the RE and LE were 0.20±0.07 and 4.56±1.12 mm, respectively, for single-pacing, when 20 μV Gaussian white noise was added to the body surface potentials at 53 body surface locations. Averaged over 8 pairs of dual pacing, the RE was 0.25±0.06 for 20 μV additive noise. The present results obtained through
Kaewkhaw, Rossukon; Kaya, Koray Dogan; Brooks, Matthew; Homma, Kohei; Zou, Jizhong; Chaitankar, Vijender; Rao, Mahendra; Swaroop, Anand
2015-12-01
The derivation of three-dimensional (3D) stratified neural retina from pluripotent stem cells has permitted investigations of human photoreceptors. We have generated a H9 human embryonic stem cell subclone that carries a green fluorescent protein (GFP) reporter under the control of the promoter of cone-rod homeobox (CRX), an established marker of postmitotic photoreceptor precursors. The CRXp-GFP reporter replicates endogenous CRX expression in vitro when the H9 subclone is induced to form self-organizing 3D retina-like tissue. At day 37, CRX+ photoreceptors appear in the basal or middle part of neural retina and migrate to apical side by day 67. Temporal and spatial patterns of retinal cell type markers recapitulate the predicted sequence of development. Cone gene expression is concomitant with CRX, whereas rod differentiation factor neural retina leucine zipper protein (NRL) is first observed at day 67. At day 90, robust expression of NRL and its target nuclear receptor NR2E3 is evident in many CRX+ cells, while minimal S-opsin and no rhodopsin or L/M-opsin is present. The transcriptome profile, by RNA-seq, of developing human photoreceptors is remarkably concordant with mRNA and immunohistochemistry data available for human fetal retina although many targets of CRX, including phototransduction genes, exhibit a significant delay in expression. We report on temporal changes in gene signatures, including expression of cell surface markers and transcription factors; these expression changes should assist in isolation of photoreceptors at distinct stages of differentiation and in delineating coexpression networks. Our studies establish the first global expression database of developing human photoreceptors, providing a reference map for functional studies in retinal cultures. PMID:26235913
NASA Astrophysics Data System (ADS)
Lev, L. L.; Krempaský, J.; Staub, U.; Rogalev, V. A.; Schmitt, T.; Shi, M.; Blaha, P.; Mishchenko, A. S.; Veligzhanin, A. A.; Zubavichus, Y. V.; Tsetlin, M. B.; Volfová, H.; Braun, J.; Minár, J.; Strocov, V. N.
2015-06-01
Electronic structure of the three-dimensional colossal magnetoresistive perovskite La1 -xSrxMnO3 has been established using soft-x-ray angle-resolved photoemission spectroscopy with its intrinsically sharp definition of three-dimensional electron momentum. The experimental results show much weaker polaronic coupling compared to the bilayer manganites and are consistent with the theoretical band structure including the empirical Hubbard parameter U. The experimental Fermi surface unveils the canonical topology of alternating three-dimensional electron spheres and hole cubes, with their shadow contours manifesting the rhombohedral lattice distortion. This picture has been confirmed by one-step photoemission calculations including displacement of the apical oxygen atoms. The rhombohedral distortion is neutral to the Jahn-Teller effect and thus polaronic coupling, but affects the double-exchange electron hopping and thus the colossal magnetoresistance effect.
Isaev, S.A.; Kharchenko, V.B.; Chudnovskii, Ya.P.
1995-06-01
A three-dimensional flow in the neighborhood of a shallow well on a plane was simulated numerically on the basis of a solution of the Reynolds equations written in curvilinear nonorthogonal coordinates and closed by a two-parametric dissipative model of turbulence.
Three dimensional characterization and archiving system
Sebastian, R.L.; Clark, R.; Gallman, P.
1995-10-01
The Three Dimensional Characterization and Archiving System (3D-ICAS) is being developed as a remote system to perform rapid in situ analysis of hazardous organics and radionuclide contamination on structural materials. Coleman Research and its subcontractors, Thermedics Detection, Inc. (TD) and the University of Idaho (UI) are in the second phase of a three phase program to develop 3D-ICAS to support Decontamination and Decommissioning (D&D) operations. Accurate physical characterization of surfaces and the radioactive and organic is a critical D&D task. Surface characterization includes identification of potentially dangerous inorganic materials, such as asbestos and transite. The 3D-ICAS system robotically conveys a multisensor probe near the surface to be inspected. The sensor position and orientation are monitored and controlled by Coherent laser radar (CLR) tracking. The ICAS fills the need for high speed automated organic analysis by means of gas chromatography-mass spectrometry sensors, and also by radionuclide sensors which combines alpha, beta, and gamma counting.
NASA Astrophysics Data System (ADS)
Prat, O. P.; Barros, A. P.
2008-05-01
In this work, we present a three-dimensional model with detailed microphysics for warm rain that emulates the transient evolution of the spatial drop size distribution (DSDs) in active storm systems. More broadly, this work is a part of an ongoing effort to merge dynamic modeling of the DSD and radar/satellite rainfall observations with the ultimate goal to improve the estimation of the vertical structure of precipitation and surface rain rates. The 3D model is evaluated against different data set of real rainfall events that include stratiform/convective configurations to estimate rain rate over a large area. A dynamic simulation of the evolution of the drop spectra is performed by using realistic boundary conditions retrieved from real rain events. Measured reflectivity fields from TRMM 2A25 products are imposed at the top of the atmospheric domain as an input to the model. In addition, the 3D model incorporates estimation of the 3D air velocity fields characterizing the simulated different rainfall regimes. The modeled temporal evolution of selected integral parameters (reflectivity: Z; rain rate: RNT) is compared against radar and TRMM 2A25 data at different heights throughout the atmospheric domain and against ground based (disdrometer, rain gauges) observations. Average residuals between 3D model and TRMM data (Z: 5%; RNT: 10-40%) are the same order of magnitude than experimental uncertainties and data retrieval procedures (Z±1dBz). Preliminary results show that 3D model rain rate matches TRMM 2A25 rain rate for rain intensity < 7-10mm/h. Above this limit TRMM PR rain rate is higher than predicted by the 3D model. This result begs the question of radar algorithm calibration and the challenge of matching the Z-R relationships to realistic rainfall regimes. The main advantage of using an explicit bin-microphysics model is that it provides a value of the surface rain rate directly from reflectivity measurements above without any assumption concerning the Z
Wirtz, Tom; Fleming, Yves; Gerard, Mathieu; Gysin, Urs; Glatzel, Thilo; Meyer, Ernst; Wegmann, Urs; Maier, Urs; Odriozola, Aitziber Herrero; Uehli, Daniel
2012-06-15
State-of-the-art secondary ion mass spectrometry (SIMS) instruments allow producing 3D chemical mappings with excellent sensitivity and spatial resolution. Several important artifacts however arise from the fact that SIMS 3D mapping does not take into account the surface topography of the sample. In order to correct these artifacts, we have integrated a specially developed scanning probe microscopy (SPM) system into a commercial Cameca NanoSIMS 50 instrument. This new SPM module, which was designed as a DN200CF flange-mounted bolt-on accessory, includes a new high-precision sample stage, a scanner with a range of 100 {mu}m in x and y direction, and a dedicated SPM head which can be operated in the atomic force microscopy (AFM) and Kelvin probe force microscopy modes. Topographical information gained from AFM measurements taken before, during, and after SIMS analysis as well as the SIMS data are automatically compiled into an accurate 3D reconstruction using the software program 'SARINA,' which was developed for this first combined SIMS-SPM instrument. The achievable lateral resolutions are 6 nm in the SPM mode and 45 nm in the SIMS mode. Elemental 3D images obtained with our integrated SIMS-SPM instrument on Al/Cu and polystyrene/poly(methyl methacrylate) samples demonstrate the advantages of the combined SIMS-SPM approach.
Three-dimensional marginal separation
NASA Technical Reports Server (NTRS)
Duck, Peter W.
1988-01-01
The three dimensional marginal separation of a boundary layer along a line of symmetry is considered. The key equation governing the displacement function is derived, and found to be a nonlinear integral equation in two space variables. This is solved iteratively using a pseudo-spectral approach, based partly in double Fourier space, and partly in physical space. Qualitatively, the results are similar to previously reported two dimensional results (which are also computed to test the accuracy of the numerical scheme); however quantitatively the three dimensional results are much different.
Three-dimensional silicon micromachining
NASA Astrophysics Data System (ADS)
Azimi, S.; Song, J.; Dang, Z. Y.; Liang, H. D.; Breese, M. B. H.
2012-11-01
A process for fabricating arbitrary-shaped, two- and three-dimensional silicon and porous silicon components has been developed, based on high-energy ion irradiation, such as 250 keV to 1 MeV protons and helium. Irradiation alters the hole current flow during subsequent electrochemical anodization, allowing the anodization rate to be slowed or stopped for low/high fluences. For moderate fluences the anodization rate is selectively stopped only at depths corresponding to the high defect density at the end of ion range, allowing true three-dimensional silicon machining. The use of this process in fields including optics, photonics, holography and nanoscale depth machining is reviewed.
Three dimensional colorimetric assay assemblies
Charych, D.; Reichart, A.
2000-06-27
A direct assay is described using novel three-dimensional polymeric assemblies which change from a blue to red color when exposed to an analyte, in one case a flu virus. The assemblies are typically in the form of liposomes which can be maintained in a suspension, and show great intensity in their color changes. Their method of production is also described.
Creating Three-Dimensional Scenes
ERIC Educational Resources Information Center
Krumpe, Norm
2005-01-01
Persistence of Vision Raytracer (POV-Ray), a free computer program for creating photo-realistic, three-dimensional scenes and a link for Mathematica users interested in generating POV-Ray files from within Mathematica, is discussed. POV-Ray has great potential in secondary mathematics classrooms and helps in strengthening students' visualization…
Three-dimensional stellarator codes
Garabedian, P. R.
2002-01-01
Three-dimensional computer codes have been used to develop quasisymmetric stellarators with modular coils that are promising candidates for a magnetic fusion reactor. The mathematics of plasma confinement raises serious questions about the numerical calculations. Convergence studies have been performed to assess the best configurations. Comparisons with recent data from large stellarator experiments serve to validate the theory. PMID:12140367
Three dimensional colorimetric assay assemblies
Charych, Deborah; Reichart, Anke
2000-01-01
A direct assay is described using novel three-dimensional polymeric assemblies which change from a blue to red color when exposed to an analyte, in one case a flu virus. The assemblies are typically in the form of liposomes which can be maintained in a suspension, and show great intensity in their color changes. Their method of production is also described.
Three-Dimensional Lissajous Figures.
ERIC Educational Resources Information Center
D'Mura, John M.
1989-01-01
Described is a mechanically driven device for generating three-dimensional harmonic space figures with different frequencies and phase angles on the X, Y, and Z axes. Discussed are apparatus, viewing stereo pairs, equations of motion, and using space figures in classroom. (YP)
Vogelius, Ivan S.; Westerly, David C.; Cannon, George M.; Mackie, Thomas R.; Mehta, Minesh P.; Sugie, Chikao; Bentzen, Soren M.
2011-07-01
Purpose: To model the possible interaction between cytotoxic chemotherapy and the radiation dose distribution with respect to the risk of radiation pneumonitis. Methods and Materials: A total of 18 non-small-cell lung cancer patients previously treated with helical tomotherapy at the University of Wisconsin were selected for the present modeling study. Three treatment plans were considered: the delivered tomotherapy plans; a three-dimensional conformal radiotherapy (3D-CRT) plan; and a fixed-field intensity-modulated radiotherapy (IMRT) plan. The IMRT and 3D-CRT plans were generated specifically for the present study. The plans were optimized without adjusting for the chemotherapy effect. The effect of chemotherapy was modeled as an independent cell killing process by considering a uniform chemotherapy equivalent radiation dose added to all voxels of the organ at risk. The risk of radiation pneumonitis was estimated for all plans using the Lyman and the critical volume models. Results: For radiotherapy alone, the critical volume model predicts that the two IMRT plans are associated with a lower risk of radiation pneumonitis than the 3D-CRT plan. However, when the chemotherapy equivalent radiation dose exceeds a certain threshold, the radiation pneumonitis risk after IMRT is greater than after 3D-CRT. This threshold dose is in the range estimated from clinical chemoradiotherapy data sets. Conclusions: Cytotoxic chemotherapy might affect the relative merit of competing radiotherapy plans. More work is needed to improve our understanding of the interaction between chemotherapy and the radiation dose distribution in clinical settings.
Hájek, Tomáš; Jandera, Pavel; Staňková, Magda; Česla, Petr
2016-05-13
A monolithic sulfobetaine polymethacrylate micro-column BIGDMA-MEDSA designed in our laboratory, shows dual retention mechanism: In acetonitrile-rich mobile phase, hydrophilic interactions control the retention (HILIC system), whereas in more aqueous mobile phases the column shows essentially reversed-phase behavior with major role of hydrophobic interactions. The zwitterionic polymethacrylate micro-column can be used in the first dimension of two-dimensional LC in alternating reversed-phase (RP) and HILIC modes, coupled with an alkyl-bonded core-shell or silica-based monolithic column in the second dimension, for HILIC×RP and RP×RP comprehensive two-dimensional separations. During the HILIC×RP period, a gradient of decreasing acetonitrile gradient is used for separation in the first dimension, so that at the end of the gradient the polymeric monolithic micro-column is equilibrated with a highly aqueous mobile phase and is ready for repeated sample injection, this time for separation under reversed-phase gradient conditions with increasing concentration of acetonitrile in the first dimension. The fast repeating reversed-phase gradients on a short silica-monolithic or core-shell column in the second dimension can be optimized independently of the actual running first-dimension gradient program. As the alternating HILIC and RP separations on the first-dimension zwitterionic methacrylate column are based on complementary retention mechanisms, the instrumental setup essentially represents two coupled two-dimensional systems. It is first time that such an automated dual LCxLC approach is reported. The novel system allows obtaining three-dimensional data in a relatively short time and can be applied not only to multidimensional gradient separations of flavones and related polyphenolic compounds. PMID:27083260
NASA Astrophysics Data System (ADS)
Heydt, M.; Divós, P.; Grunze, M.; Rosenhahn, A.
2009-10-01
In this article we describe the technical aspects of digital in-line holographic microscopy to track multiple macrofouling Ulva linza zoospores simultaneously during their exploration of surfaces. Using an effective method of artefact suppression at the edges of holograms in combination with projection of volume reconstructions, a fast algorithm was developed which allows a reliable determination of a large number of subsequent spore positions. Thus, statistical analysis of swimming behaviour in the vicinity of surfaces becomes possible. Using glass surfaces as example, velocity and diving direction distributions are calculated and the swimming behaviour is statistically analysed. Diving direction analysis provides a straightforward way to determine segments within traces with surface contact. The presented method of data analysis allows high throughput analysis of holographic microscopy data and sets the basis for different applications including biofouling.
Three-dimensional null point reconnection regimes
Priest, E. R.; Pontin, D. I.
2009-12-15
Recent advances in theory and computational experiments have shown the need to refine the previous categorization of magnetic reconnection at three-dimensional null points--points at which the magnetic field vanishes. We propose here a division into three different types, depending on the nature of the flow near the spine and fan of the null. The spine is an isolated field line which approaches the null (or recedes from it), while the fan is a surface of field lines which recede from it (or approach it). So-called torsional spine reconnection occurs when field lines in the vicinity of the fan rotate, with current becoming concentrated along the spine so that nearby field lines undergo rotational slippage. In torsional fan reconnection field lines near the spine rotate and create a current that is concentrated in the fan with a rotational flux mismatch and rotational slippage. In both of these regimes, the spine and fan are perpendicular and there is no flux transfer across spine or fan. The third regime, called spine-fan reconnection, is the most common in practice and combines elements of the previous spine and fan models. In this case, in response to a generic shearing motion, the null point collapses to form a current sheet that is focused at the null itself, in a sheet that locally spans both the spine and fan. In this regime the spine and fan are no longer perpendicular and there is flux transfer across both of them.
Hapca, Simona; Baveye, Philippe C.; Wilson, Clare; Lark, Richard Murray; Otten, Wilfred
2015-01-01
There is currently a significant need to improve our understanding of the factors that control a number of critical soil processes by integrating physical, chemical and biological measurements on soils at microscopic scales to help produce 3D maps of the related properties. Because of technological limitations, most chemical and biological measurements can be carried out only on exposed soil surfaces or 2-dimensional cuts through soil samples. Methods need to be developed to produce 3D maps of soil properties based on spatial sequences of 2D maps. In this general context, the objective of the research described here was to develop a method to generate 3D maps of soil chemical properties at the microscale by combining 2D SEM-EDX data with 3D X-ray computed tomography images. A statistical approach using the regression tree method and ordinary kriging applied to the residuals was developed and applied to predict the 3D spatial distribution of carbon, silicon, iron, and oxygen at the microscale. The spatial correlation between the X-ray grayscale intensities and the chemical maps made it possible to use a regression-tree model as an initial step to predict the 3D chemical composition. For chemical elements, e.g., iron, that are sparsely distributed in a soil sample, the regression-tree model provides a good prediction, explaining as much as 90% of the variability in some of the data. However, for chemical elements that are more homogenously distributed, such as carbon, silicon, or oxygen, the additional kriging of the regression tree residuals improved significantly the prediction with an increase in the R2 value from 0.221 to 0.324 for carbon, 0.312 to 0.423 for silicon, and 0.218 to 0.374 for oxygen, respectively. The present research develops for the first time an integrated experimental and theoretical framework, which combines geostatistical methods with imaging techniques to unveil the 3-D chemical structure of soil at very fine scales. The methodology presented
Radiative transfer for a three-dimensional raining cloud
NASA Technical Reports Server (NTRS)
Haferman, J. L.; Krajewski, W. F.; Smith, T. F.; Sanchez, A.
1993-01-01
Satellite-sensor-based microwave brightness temperatures for a three-dimensional raining cloud over a reflecting surface are computed by using a radiative transfer model based on the discrete-ordinates solution procedure. The three-dimensional model applied to a plane layer is validated by comparison with results from a one-dimensional model that is available in the literature. Results examining the effects of cloud height, rainfall rate, surface reflectance, rainfall footprint area, and satellite viewing position on one- and three-dimensional brightness temperature calculations are reported. The numerical experiments indicate that, under certain conditions, three-dimensional effects are significant in the analysis of satellite-sensor-based rainfall retrieval algorithms. The results point to the need to consider carefully three-dimensional effects as well as surface reflectance effects when interpreting satellite-measured radiation data.
Three-dimensional fault drawing
Dongan, L. )
1992-01-01
In this paper, the author presents a structure interpretation based on three-dimensional fault drawing. It is required that fault closure must be based on geological theory, spacial plotting principle and restrictions in seismic exploration. Geological structure can be well ascertained by analysing the shapes and interrelation of the faults which have been drawn through reasonable fault point closure and fault point correlation. According to this method, the interrelation of fault points is determined by first closing corresponding fault points in intersecting sections, then reasonably correlating the relevant fault points. Fault point correlation is not achieved in base map, so its correctness can be improved greatly. Three-dimensional fault closure is achieved by iteratively revising. The closure grid should be densified gradually. The distribution of major fault system is determined prior to secondary faults. Fault interpretation by workstation also follows this procedure.
Three-dimensional obstetric ultrasound.
Tache, Veronique; Tarsa, Maryam; Romine, Lorene; Pretorius, Dolores H
2008-04-01
Three-dimensional ultrasound has gained a significant popularity in obstetrical practice in recent years. The advantage of this modality in some cases is in question, however. This article provides a basic review of volume acquisition, mechanical positioning, and display modalities. Multiple uses of this technique in obstetrical care including first trimester applications and its utility in clarification of fetal anatomy such as brain, face, heart, and skeleton is discussed. PMID:18450140
Three-dimensional coronary angiography
NASA Astrophysics Data System (ADS)
Suurmond, Rolf; Wink, Onno; Chen, James; Carroll, John
2005-04-01
Three-Dimensional Coronary Angiography (3D-CA) is a novel tool that allows clinicians to view and analyze coronary arteries in three-dimensional format. This will help to find accurate length estimates and to find the optimal viewing angles of a lesion based on the three-dimensional vessel orientation. Various advanced algorithms are incorporated in this 3D processing utility including 3D-RA calibration, ECG phase selection, 2D vessel extraction, and 3D vessel modeling into a utility with optimized workflow and ease-of-use features, which is fully integrated in the environment of the x-ray catheterization lab. After the 3D processing, the 3D vessels can be viewed and manipulated interactively inside the operating room. The TrueView map provides a quick overview of gantry angles with optimal visualization of a single or bifurcation lesion. Vessel length measurements can be performed without risk of underestimating a vessel segment due to foreshortening. Vessel cross sectional diameters can also be measured. Unlike traditional, projection-based quantitative coronary analysis, the additional process of catheter calibration is not needed for diameter measurements. Validation studies show a high reproducibility of the measurements, with little user dependency.
Analysis of three-dimensional transonic compressors
NASA Technical Reports Server (NTRS)
Bourgeade, A.
1984-01-01
A method for computing the three-dimensional transonic flow around the blades of a compressor or of a propeller is given. The method is based on the use of the velocity potential, on the hypothesis that the flow is inviscid, irrotational and isentropic. The equation of the potential is solved in a transformed space such that the surface of the blade is mapped into a plane where the periodicity is implicit. This equation is in a nonconservative form and is solved with the help of a finite difference method using artificial time. A computer code is provided and some sample results are given in order to demonstrate the influence of three-dimensional effects and the blade's rotation.
Wu, John Z.; Dong, Ren G.; Warren, Christopher M.; Welcome, Daniel E.; McDowell, Thomas W.
2015-01-01
Contact interactions between the hand and handle, such as the contact surface softness and contact surface curvature, will affect both physical effort and musculoskeletal fatigue, thereby the comfort and safety of power tool operations. Previous models of hand gripping can be categorized into two groups: multi-body dynamic models and finite element (FE) models. The goal of the current study is to develop a hybrid FE hand gripping model, which combines the features of conventional FE models and multi-body dynamic models. The proposed model is applied to simulate hand-gripping on a cylindrical handle with covering materials of different softness levels. The model included three finger segments (distal, middle, and proximal phalanxes), three finger joints (the distal interphalangeal (DIP), proximal interphalangeal (PIP), and metacarpophalangeal (MCP) joint), and major anatomical substructures. The model was driven by joint moments, which are the net effects of all passive and active muscular forces acting about the joints. The finger model was first calibrated by using experimental data of human subject tests, and then applied to investigate the effects of surface softness on contact interactions between a finger and a cylindrical handle. Our results show that the maximal compressive stress and strain in the soft tissues of the fingers can be effectively reduced by reducing the stiffness of the covering material. PMID:24736020
Three-Dimensional Imaging. Chapter 10
NASA Technical Reports Server (NTRS)
Kelso, R. M.; Delo, C.
1999-01-01
This chapter is concerned with three-dimensional imaging of fluid flows. Although relatively young, this field of research has already yielded an enormous range of techniques. These vary widely in cost and complexity, with the cheapest light sheet systems being within the budgets of most laboratories, and the most expensive Magnetic Resonance Imaging systems available to a select few. Taking the view that the most likely systems to be developed are those using light sheets, the authors will relate their knowledge and experience of such systems. Other systems will be described briefly and references provided. Flows are inherently three-dimensional in structure; even those generated around nominally 2-D surface geometry. It is becoming increasingly apparent to scientists and engineers that the three-dimensionalities, both large and small scale, are important in terms of overall flow structure and species, momentum, and energy transport. Furthermore, we are accustomed to seeing the world in three dimensions, so it is natural that we should wish to view, measure and interpret flows in three-dimensions. Unfortunately, 3-D images do not lend themselves to convenient presentation on the printed page, and this task is one of the challenges facing us.
Three-dimensional Camera Phone
NASA Astrophysics Data System (ADS)
Iizuka, Keigo
2004-12-01
An inexpensive technique for realizing a three-dimensional (3D) camera phone display is presented. Light from the liquid-crystal screen of a camera phone is linearly polarized, and its direction of polarization is easily manipulated by a cellophane sheet used as a half-waveplate. The novel 3D camera phone display is made possible solely by optical components without resorting to computation, so that the 3D image is displayed in real time. Quality of the original image is not sacrificed in the process of converting it into a 3D image.
Three-dimensional visual stimulator
NASA Astrophysics Data System (ADS)
Takeda, Tsunehiro; Fukui, Yukio; Hashimoto, Keizo; Hiruma, Nobuyuki
1995-02-01
We describe a newly developed three-dimensional visual stimulator (TVS) that can change independently the directions, distances, sizes, luminance, and varieties of two sets of targets for both eyes. It consists of liquid crystal projectors (LCP's) that generate the flexible images of targets, Badal otometers that change target distances without changing the visual angles, and relay-lens systems that change target directions. A special control program is developed for real-time control of six motors and two LCP's in the TVS together with a three-dimensional optometer III that simultaneously measures eye movement, accommodation, pupil diameter, and head movement. distance, 0 to -20 D; direction, 16 horizontally and 15 vertically; size, 0-2 deg visual angle; and luminance, 10-2-10 2 cd/m2. The target images are refreshed at 60 Hz and speeds with which the target makes a smooth change (ramp stimuli) are size, 10 deg/s. A simple application demonstrates the performance.
Three-dimensional stereo by photometric ratios
Wolff, L.B.; Angelopoulou, E.
1994-11-01
We present a methodology for corresponding a dense set of points on an object surface from photometric values for three-dimensional stereo computation of depth. The methodology utilizes multiple stereo pairs of images, with each stereo pair being taken of the identical scene but under different illumination. With just two stereo pairs of images taken under two different illumination conditions, a stereo pair of ratio images can be produced, one for the ratio of left-hand images and one for the ratio of right-hand images. We demonstrate how the photometric ratios composing these images can be used for accurate correspondence of object points. Object points having the same photometric ratio with respect to two different illumination conditions constitute a well-defined equivalence class of physical constraints defined by local surface orientation relative to illumination conditions. We formally show that for diffuse reflection the photometric ratio is invariant to varying camera characteristics, surface albedo, and viewpoint and that therefore the same photometric ratio in both images of a stereo pair implies the same equivalence class of physical constraints. The correspondence of photometric ratios along epipolar lines in a stereo pair of images under different illumination conditions is a correspondence of equivalent physical constraints, and the determination of depth from stereo can be performed. Whereas illumination planning is required, our photometric-based stereo methodology does not require knowledge of illumination conditions in the actual computation of three-dimensional depth and is applicable to perspective views. This technique extends the stereo determination of three-dimensional depth to smooth featureless surfaces without the use of precisely calibrated lighting. We demonstrate experimental depth maps from a dense set of points on smooth objects of known ground-truth shape, determined to within 1% depth accuracy.
NASA Astrophysics Data System (ADS)
Wang, Youhua; Wang, Junhua; Ho, S. L.; Pang, Lingling; Fu, W. N.
2011-04-01
In this paper, neural networks with a finite element method (FEM) were introduced to predict eddy current distributions on the continuously moving thin conducting strips in traveling wave induction heating (TWIH) equipments. A method that combines a neural network with a finite element method (FEM) is proposed to optimize eddy current distributions of TWIH heater. The trained network used for tested examples shows quite good accuracy of the prediction. The results have then been used with reference to a double-side TWIH in order to analyze the distributions of the magnetic field and eddy current intensity, which accelerates the iterative solution process for the nonlinear coupled electromagnetic matters. The FEM computation of temperature converged conspicuously faster using the prediction results as initial values than using the zero values, and the number of iterations is reduced dramatically. Simulation results demonstrate the effectiveness and characteristics of the proposed method.
NASA Technical Reports Server (NTRS)
Demerdash, N. A.; Wang, R.; Secunde, R.
1992-01-01
A 3D finite element (FE) approach was developed and implemented for computation of global magnetic fields in a 14.3 kVA modified Lundell alternator. The essence of the new method is the combined use of magnetic vector and scalar potential formulations in 3D FEs. This approach makes it practical, using state of the art supercomputer resources, to globally analyze magnetic fields and operating performances of rotating machines which have truly 3D magnetic flux patterns. The 3D FE-computed fields and machine inductances as well as various machine performance simulations of the 14.3 kVA machine are presented in this paper and its two companion papers.
NASA Astrophysics Data System (ADS)
De Magalhães, Nzola; Liaw, Lih-Huei L.; Li, Linda; Liogys, Angela; Madsen, Steen J.; Hirschberg, Henry; Tromberg, Bruce J.
2006-02-01
An in-vivo tumor model composed of multicellular human glioma spheroids implanted on a shell-less chorioallantoic membrane (CAM), has been developed. Following removal of a portion of the ectodermal epithelium layer of the CAM, human glioma spheroids were implanted on day 7 of embryonic development. Tumor invasion, rapid growth and vasculature formation were observed 7 days post implantation. Single tumor cell migration towards blood vessels, angiogenesis and satellite tumor growth were also evident. The human tumor/CAM model is being used to examine the effects of combined ALA PDT and anti-angiogenic agents. The shell-less CAM is well suited for topical, i.p. and i.v. photosensitizer and/or drug application.
NASA Technical Reports Server (NTRS)
Reddy, C. J.; Deshpande, M. D.; Cockrell, C. R.; Beck, F. B.
1995-01-01
A combined finite element method (FEM) and method of moments (MoM) technique is presented to analyze the radiation characteristics of a cavity-fed aperture in three dimensions. Generalized feed modeling has been done using the modal expansion of fields in the feed structure. Numerical results for some feeding structures such as a rectangular waveguide, circular waveguide, and coaxial line are presented. The method also uses the geometrical theory of diffraction (GTD) to predict the effect of a finite ground plane on radiation characteristics. Input admittance calculations for open radiating structures such as a rectangular waveguide, a circular waveguide, and a coaxial line are shown. Numerical data for a coaxial-fed cavity with finite ground plane are verified with experimental data.
Obtaining three-dimensional height profiles from a two-dimensional slope measuring instrument
Irick, S.C.; Kaza, R.K.; McKinney, W.R. )
1995-02-01
The long trace profiler (LTP) was developed in order to measure the mid- and long-period variations in optical components for beamlines of high-brightness synchrotron sources. The LTP is a slope measuring instrument, and the optic under test is typically measured along a single tangential line, giving a two-dimensional profile. If a three-dimensional height profile (surface map) is desired, it is necessary to combine the integrated slopes of several measurements. A series of LTP measurements and a data processing method used to combine standard LTP data into a three-dimensional height profile are described. The measurement of a synchrotron beamline mirror and its three-dimensional height profile are presented.
NASA Astrophysics Data System (ADS)
Ahn, SeungHyun; Koh, Young Ho; Kim, GeunHyung
2010-06-01
Collagen has the advantage of being very similar to macromolecular substances that can be recognized and metabolized in the biological environment. Although the natural material has superior property for this purpose, its use to fabricate reproducible and pore-structure-controlled 3D structures, which are designed to allow the entry of sufficient cells and the easy diffusion of nutrients, has been limited due to its low processability. Here, we propose a hybrid technology that combines a cryogenic plotting system with an electrospinning process. Using this technique, an easily pore-size-controllable hierarchical 3D scaffold consisting of micro-sized highly porous collagen strands and micro/nano-sized collagen fibers was fabricated. The pore structure of the collagen scaffold was controlled by the collagen micro/nanofibers, which were layered in the scaffold. The hierarchical scaffolds were characterized with respect to initial cell attachment and proliferation of bone marrow-derived mesenchymal stem cells within the scaffolds. The hierarchical scaffold exhibited incredibly enhanced initial cell attachment and cell compactness between pores of the plotted scaffold relative to the normally designed 3D collagen scaffold.
Small, William; Mulcahy, Mary F.; Rademaker, Alfred; Bentrem, David J.; Benson, Al B.; Weitner, Bing Bing; Talamonti, Mark S.
2011-06-01
Purpose: To evaluate response rate, survival, and toxicity in patients with nonmetastatic pancreatic cancer treated with gemcitabine, bevacizumab, and radiotherapy. Methods and Materials: Patients received three cycles of therapy over 10 weeks. In total, treatment consisted of intravenous (IV) gemcitabine, 1,000 mg/m{sup 2}, every 1 to 2 weeks (7 doses), IV bevacizumab, 10 mg/kg every 2 weeks (5 doses), and 36 Gy of radiotherapy (2.4-Gy fractions during cycle two). Response was assessed by cross-sectional imaging and carbohydrate antigen 19-9 (CA 19-9) levels. Patients with resectable tumors underwent surgery 6 to 8 weeks after the last dose of bevacizumab. Maintenance gemcitabine and bevacizumab doses were delivered to patients who had unresected tumors and no progression. Results: Twenty-eight of the 32 enrolled patients completed all three cycles. The median follow-up was 11.07 months. Most grade 3 or 4 toxicities occurred in the initial treatment phase; the most frequent toxicities were leukopenia (21%), neutropenia (17%), and nausea (17%). At week 10, 1 patient (4%) had a complete response, 2 patients (7%) had partial responses, 21 patients (75%) had stable disease, and 4 patients (14%) had progressive disease. The median pretreatment and posttreatment CA 19-9 levels (25 patients) were 184.3 and 57.9 U/ml, respectively (p = 0.0006). One of 10 patients proceeding to surgery experienced a major complication. Two of 6 patients undergoing resection had complete pathologic responses. The median progression-free and overall survival durations were 9.9 months and 11.8 months, respectively. Conclusions: The combination of full-dose gemcitabine, bevacizumab, and radiotherapy was active and was not associated with a high rate of major surgical complications.
Two component-three dimensional catalysis
Schwartz, Michael; White, James H.; Sammells, Anthony F.
2002-01-01
This invention relates to catalytic reactor membranes having a gas-impermeable membrane for transport of oxygen anions. The membrane has an oxidation surface and a reduction surface. The membrane is coated on its oxidation surface with an adherent catalyst layer and is optionally coated on its reduction surface with a catalyst that promotes reduction of an oxygen-containing species (e.g., O.sub.2, NO.sub.2, SO.sub.2, etc.) to generate oxygen anions on the membrane. The reactor has an oxidation zone and a reduction zone separated by the membrane. A component of an oxygen containing gas in the reduction zone is reduced at the membrane and a reduced species in a reactant gas in the oxidation zone of the reactor is oxidized. The reactor optionally contains a three-dimensional catalyst in the oxidation zone. The adherent catalyst layer and the three-dimensional catalyst are selected to promote a desired oxidation reaction, particularly a partial oxidation of a hydrocarbon.
Three-dimensional singular points in aerodynamics
NASA Technical Reports Server (NTRS)
Unal, Aynur
1988-01-01
When three-dimensional separation occurs on a body immersed in a flow governed by the incompressible Navier-Stokes equations, the geometrical surfaces formed by the three vector fields (velocity, vorticity and the skin-friction) and a scalar field (pressure) become interrelated through topological maps containing their respective singular points and extremal points. A mathematically consistent description of these singular points becomes inevitable when we want to study the geometry of the separation. A separated stream surface requires, for example, the existence of a saddle-type singular point on the skin-friction surface. This singular point is actually, in the proper language of mathematics, a saddle of index two. The index is a measure of the dimension of the outset (set leaving the singular point). Hence, when a saddle of index two is specified, a two dimensional surface that becomes separated from the osculating plane of the saddle is implied. The three-dimensional singular point is interpreted mathematically and the most common aerodynamical singular points are discussed through this perspective.
High resolution three-dimensional doping profiler
Thundat, Thomas G.; Warmack, Robert J.
1999-01-01
A semiconductor doping profiler provides a Schottky contact at one surface and an ohmic contact at the other. While the two contacts are coupled to a power source, thereby establishing an electrical bias in the semiconductor, a localized light source illuminates the semiconductor to induce a photocurrent. The photocurrent changes in accordance with the doping characteristics of the semiconductor in the illuminated region. By changing the voltage of the power source the depth of the depletion layer can be varied to provide a three dimensional view of the local properties of the semiconductor.
Three-dimensional lock and key colloids.
Wang, Yu; Wang, Yufeng; Zheng, Xiaolong; Yi, Gi-Ra; Sacanna, Stefano; Pine, David J; Weck, Marcus
2014-05-14
Colloids with well-defined multicavities are synthesized through the hydrolytic removal of silica cluster templates from organo-silica hybrid patchy particles. The geometry of the cavities stems from the originally assembled cluster templates, displaying well-defined three-dimensional symmetries, ranging from spherical, linear, triangular, tetrahedral, trigonal dipyramidal, octahedral, to pentagonal dipyramidal. The concave surface of the cavities is smooth, and the cavity shallowness and size can be varied. These particles with multicavities can act as "lock" particles with multiple "key holes". Up to n "key" particles can self-assemble into the lock particles via depletion interaction, resulting in multivalent, site-specific, reversible, and flexible bonding. PMID:24785203
Three-dimensional coil inductor
Bernhardt, Anthony F.; Malba, Vincent
2002-01-01
A three-dimensional coil inductor is disclosed. The inductor includes a substrate; a set of lower electrically conductive traces positioned on the substrate; a core placed over the lower traces; a set of side electrically conductive traces laid on the core and the lower traces; and a set of upper electrically conductive traces attached to the side traces so as to form the inductor. Fabrication of the inductor includes the steps of forming a set of lower traces on a substrate; positioning a core over the lower traces; forming a set of side traces on the core; connecting the side traces to the lower traces; forming a set of upper traces on the core; and connecting the upper traces to the side traces so as to form a coil structure.
Rykaczewski, Konrad; Hildreth, Owen J; Kulkarni, Dhaval; Henry, Matthew R; Kim, Song-Kil; Wong, Ching Ping; Tsukruk, Vladimir V; Fedorov, Andrei G
2010-04-01
In this work, we introduce a maskless, resist-free rapid prototyping method to fabricate three-dimensional structures using electron beam induced deposition (EBID) of amorphous carbon (aC) from a residual hydrocarbon precursor in combination with metal-assisted chemical etching (MaCE) of silicon. We demonstrate that EBID-made patterned aC coating, with thickness of even a few nanometers, acts as a negative "mask" for the etching process and is sufficient for localized termination of the MaCE of silicon. Optimal aC deposition settings and gold film thickness for fabrication of high-aspect-ratio nanoscale 3D silicon structures are determined. The speed necessary for optimal aC feature deposition is found to be comparable to the writing speed of standard Electron Beam Lithography and the MaCE etching rate is found to be comparable to standard deep reactive ion etching (DRIE) rate. PMID:20356053
Three dimensional magnetic abacus memory
NASA Astrophysics Data System (ADS)
Zhang, Shilei; Zhang, Jingyan; Baker, Alexander A.; Wang, Shouguo; Yu, Guanghua; Hesjedal, Thorsten
2014-08-01
Stacking nonvolatile memory cells into a three-dimensional matrix represents a powerful solution for the future of magnetic memory. However, it is technologically challenging to access the data in the storage medium if large numbers of bits are stacked on top of each other. Here we introduce a new type of multilevel, nonvolatile magnetic memory concept, the magnetic abacus. Instead of storing information in individual magnetic layers, thereby having to read out each magnetic layer separately, the magnetic abacus adopts a new encoding scheme. It is inspired by the idea of second quantisation, dealing with the memory state of the entire stack simultaneously. Direct read operations are implemented by measuring the artificially engineered `quantised' Hall voltage, each representing a count of the spin-up and spin-down layers in the stack. This new memory system further allows for both flexible scaling of the system and fast communication among cells. The magnetic abacus provides a promising approach for future nonvolatile 3D magnetic random access memory.
Three dimensional magnetic abacus memory
NASA Astrophysics Data System (ADS)
Zhang, Shilei; Zhang, Jingyan; Baker, Alexander; Wang, Shouguo; Yu, Guanghua; Hesjedal, Thorsten
2015-03-01
Stacking nonvolatile memory cells into a three-dimensional matrix represents a powerful solution for the future of magnetic memory. However, it is technologically challenging to access the individual data in the storage medium if large numbers of bits are stacked on top of each other. Here we introduce a new type of multilevel, nonvolatile magnetic memory concept, the magnetic abacus. Instead of storing information in individual magnetic layers, thereby having to read out each magnetic layer separately, the magnetic abacus adopts a new encoding scheme which envisages a classical abacus with the beads operated by electron spins. It is inspired by the idea of second quantization, dealing with the memory state of the entire stack simultaneously. Direct read operations are implemented by measuring the artificially engineered `quantized' Hall voltage, representing a count of the spin-up and spin-down layers in the stack. This concept of `second quantization of memory' realizes the 3D memory architecture with superior reading and operation efficiency, thus is a promising approach for future nonvolatile magnetic random access memory.
Three dimensional magnetic abacus memory.
Zhang, ShiLei; Zhang, JingYan; Baker, Alexander A; Wang, ShouGuo; Yu, GuangHua; Hesjedal, Thorsten
2014-01-01
Stacking nonvolatile memory cells into a three-dimensional matrix represents a powerful solution for the future of magnetic memory. However, it is technologically challenging to access the data in the storage medium if large numbers of bits are stacked on top of each other. Here we introduce a new type of multilevel, nonvolatile magnetic memory concept, the magnetic abacus. Instead of storing information in individual magnetic layers, thereby having to read out each magnetic layer separately, the magnetic abacus adopts a new encoding scheme. It is inspired by the idea of second quantisation, dealing with the memory state of the entire stack simultaneously. Direct read operations are implemented by measuring the artificially engineered 'quantised' Hall voltage, each representing a count of the spin-up and spin-down layers in the stack. This new memory system further allows for both flexible scaling of the system and fast communication among cells. The magnetic abacus provides a promising approach for future nonvolatile 3D magnetic random access memory. PMID:25146338
Dynamic Three-Dimensional Echocardiography
NASA Astrophysics Data System (ADS)
Matsusaka, Katsuhiko; Doi, Motonori; Oshiro, Osamu; Chihara, Kunihiro
2000-08-01
Conventional three-dimensional (3D) ultrasound imaging equipment for diagnosis requires much time to reconstruct 3D images or fix the view point for observing the 3D image. Thus, it is inconvenient for cardiac diagnosis. In this paper, we propose a new dynamic 3D echocardiography system. The system produces 3D images in real-time and permits changes in view point. This system consists of ultrasound diagnostic equipment, a digitizer and a computer. B-mode images are projected to a virtual 3D space by referring to the position of the probe of the ultrasound diagnosis equipment. The position is obtained by the digitizer to which the ultrasound probe is attached. The 3D cardiac image is constructed from B-mode images obtained simultaneously in the cardiac cycle. To obtain the same moment of heartbeat in the cardiac cycle, this system uses the electrocardiography derived from the diagnosis equipment. The 3D images, which show various scenes of the stage of heartbeat action, are displayed sequentially. The doctor can observe 3D images cut in any plane by pushing a button of the digitizer and zooming with the keyboard. We evaluated our prototype system by observation of a mitral valve in motion.
Three-dimensional display technologies
Geng, Jason
2014-01-01
The physical world around us is three-dimensional (3D), yet traditional display devices can show only two-dimensional (2D) flat images that lack depth (i.e., the third dimension) information. This fundamental restriction greatly limits our ability to perceive and to understand the complexity of real-world objects. Nearly 50% of the capability of the human brain is devoted to processing visual information [Human Anatomy & Physiology (Pearson, 2012)]. Flat images and 2D displays do not harness the brain’s power effectively. With rapid advances in the electronics, optics, laser, and photonics fields, true 3D display technologies are making their way into the marketplace. 3D movies, 3D TV, 3D mobile devices, and 3D games have increasingly demanded true 3D display with no eyeglasses (autostereoscopic). Therefore, it would be very beneficial to readers of this journal to have a systematic review of state-of-the-art 3D display technologies. PMID:25530827
Three-dimensional laser microvision.
Shimotahira, H; Iizuka, K; Chu, S C; Wah, C; Costen, F; Yoshikuni, Y
2001-04-10
A three-dimensional (3-D) optical imaging system offering high resolution in all three dimensions, requiring minimum manipulation and capable of real-time operation, is presented. The system derives its capabilities from use of the superstructure grating laser source in the implementation of a laser step frequency radar for depth information acquisition. A synthetic aperture radar technique was also used to further enhance its lateral resolution as well as extend the depth of focus. High-speed operation was made possible by a dual computer system consisting of a host and a remote microcomputer supported by a dual-channel Small Computer System Interface parallel data transfer system. The system is capable of operating near real time. The 3-D display of a tunneling diode, a microwave integrated circuit, and a see-through image taken by the system operating near real time are included. The depth resolution is 40 mum; lateral resolution with a synthetic aperture approach is a fraction of a micrometer and that without it is approximately 10 mum. PMID:18357177
Three-Dimensional Schlieren Measurements
NASA Astrophysics Data System (ADS)
Sutherland, Bruce; Cochrane, Andrea
2004-11-01
Schlieren systems visualise disturbances that change the index of refraction of a fluid, for example due to temperature or salinity disturbances. `Synthetic schlieren' refers to a recent advance in which these disturbances are visualised with a digital camera and image-processing technology rather than the classical use of parabolic mirrors and a knife-edge. In a typical setup, light from an image of horizontal lines or dots passes almost horizontally through the test section of a fluid to a CCD camera. Refractive index disturbances distort the image and digital comparison of successive images reveals the plan-form structure and time evolution of the disturbances. If the disturbance is effectively two-dimensional, meaning that it is uniform across the line-of-sight of the camera, then its magnitude as well as its structure can measured through simple inversion of an algebraic equation. If the structure is axisymmetric with rotation-axis perpendicular to the line of sight, the magnitude of the disturbance can be measured through inversion of a non-singular square matrix. Here we report upon the extension of this work toward measuring the magnitude of a fully three-dimensional disturbance. This is done by analysing images from two perspectives through the test section and using inversion tomography techniques to reconstruct the disturbance field. The results are tested against theoretical predictions and experimental measurements.
NASA Astrophysics Data System (ADS)
Kornreich, Philipp; Farell, Bart
2013-01-01
An imager that can measure the distance from each pixel to the point on the object that is in focus at the pixel is described. This is accomplished by short photo-conducting lightguides at each pixel. In the eye the rods and cones are the fiber-like lightguides. The device uses ambient light that is only coherent in spherical shell-shaped light packets of thickness of one coherence length. Modern semiconductor technology permits the construction of lightguides shorter than a coherence length of ambient light. Each of the frequency components of the broad band light arriving at a pixel has a phase proportional to the distance from an object point to its image pixel. Light frequency components in the packet arriving at a pixel through a convex lens add constructively only if the light comes from the object point in focus at this pixel. The light in packets from all other object points cancels. Thus the pixel receives light from one object point only. The lightguide has contacts along its length. The lightguide charge carriers are generated by the light patterns. These light patterns, and thus the photocurrent, shift in response to the phase of the input signal. Thus, the photocurrent is a function of the distance from the pixel to its object point. Applications include autonomous vehicle navigation and robotic vision. Another application is a crude teleportation system consisting of a camera and a three-dimensional printer at a remote location.
Use of three-dimensional photoelasticity in fracture mechanics
NASA Technical Reports Server (NTRS)
Smith, C. W.
1973-01-01
The philosophy of fracture mechanics is reviewed and utilized to formulate a simplified approach to the determination of the stress-intensity factor photoelastically for three-dimensional problems. The method involves a Taylor Series correction for the maximum in-plane shear stress (TSCM) and does not involve stress separation. The results are illustrated by applying the TSCM to surface flaws in bending fields. Other three-dimensional problems solved by the TSCM are cited.
Baum, R.L.; Messerich, J.; Fleming, R.W.
1998-01-01
Two slow-moving landslides in Honolulu, Hawaii, were the subject of photogrammetric measurements, field mapping, and subsurface investigation to learn whether surface observations can yield useful information consistent with results of subsurface investigation. Mapping focused on structural damage and on surface features such as scarps, shears, and toes. The x-y-z positions of photo-identifiable points were obtained from aerial photographs taken at three different times. The measurements were intended to learn if the shape of the landslide failure surface can be determined from systematic surface observations and whether surface observations about deformation are consistent with photogrammetrically-obtained displacement gradients. Field and aerial photographic measurements were evaluated to identify the boundaries of the landslides, distinguish areas of incipient landslide enlargement, and identify zones of active and passive failure in the landslides. Data reported here apply mainly to the Alani-Paty landslide, a translational, earth-block landslide that damaged property in a 3.4-ha residential area. It began moving in the 1970s and displacement through 1991 totaled 4 m. Thickness, determined from borehole data, ranges from about 7 to 10 m; and the slope of the ground surface averages about 9??. Field evidence of deformation indicated areas of potential landslide enlargement outside the well-formed landslide boundaries. Displacement gradients obtained photogrammetrically and deformation mapping both identified similar zones of active failure (longitudinal stretching) and passive failure (longitudinal shortening) within the body of the landslide. Surface displacement on the landslide is approximately parallel to the broadly concave slip surface.
Three-dimensional fluorescence lifetime tomography
Godavarty, Anuradha; Sevick-Muraca, Eva M.; Eppstein, Margaret J.
2005-04-01
Near-infrared fluorescence tomography using molecularly targeted lifetime-sensitive, fluorescent contrast agents have applications for early-stage cancer diagnostics. Yet, although the measurement of fluorescent lifetime imaging microscopy (FLIM) is extensively used in microscopy and spectroscopy applications, demonstration of fluorescence lifetime tomography for medical imaging is limited to two-dimensional studies. Herein, the feasibility of three-dimensional fluorescence-lifetime tomography on clinically relevant phantom volumes is established, using (i) a gain-modulated intensified charge coupled device (CCD) and modulated laser diode imaging system, (ii) two fluorescent contrast agents, e.g., Indocyanine green and 3-3'-Diethylthiatricarbocyanine iodide differing in their fluorescence lifetime by 0.62 ns, and (iii) a two stage approximate extended Kalman filter reconstruction algorithm. Fluorescence measurements of phase and amplitude were acquired on the phantom surface under different target to background fluorescence absorption (70:1, 100:1) and fluorescence lifetime (1:1, 2.1:1) contrasts at target depths of 1.4-2 cm. The Bayesian tomography algorithm was employed to obtain three-dimensional images of lifetime and absorption owing to the fluorophores.
Three-dimensional turbopump flowfield analysis
NASA Technical Reports Server (NTRS)
Sharma, O. P.; Belford, K. A.; Ni, R. H.
1992-01-01
A program was conducted to develop a flow prediction method applicable to rocket turbopumps. The complex nature of a flowfield in turbopumps is described and examples of flowfields are discussed to illustrate that physics based models and analytical calculation procedures based on computational fluid dynamics (CFD) are needed to develop reliable design procedures for turbopumps. A CFD code developed at NASA ARC was used as the base code. The turbulence model and boundary conditions in the base code were modified, respectively, to: (1) compute transitional flows and account for extra rates of strain, e.g., rotation; and (2) compute surface heat transfer coefficients and allow computation through multistage turbomachines. Benchmark quality data from two and three-dimensional cascades were used to verify the code. The predictive capabilities of the present CFD code were demonstrated by computing the flow through a radial impeller and a multistage axial flow turbine. Results of the program indicate that the present code operated in a two-dimensional mode is a cost effective alternative to full three-dimensional calculations, and that it permits realistic predictions of unsteady loadings and losses for multistage machines.
NASA Astrophysics Data System (ADS)
Sessi, P.; Storz, O.; Bathon, T.; Wilfert, S.; Kokh, K. A.; Tereshchenko, O. E.; Bihlmayer, G.; Bode, M.
2016-01-01
The binary chalcogenides Bi2Te3 and Bi2Se3 are the most widely studied topological insulators. Although the quantum anomalous Hall effect has recently been observed in magnetically doped Sb2Te3 , this compound has been studied to a much lesser extent. Here, by using energy-resolved quasiparticle interference mapping, we investigate the scattering events of pristine Sb2Te3 surfaces. We find that, in addition to the Dirac fermions, another strongly spin-polarized surface resonance emerges at higher energies in the unoccupied electronic states. Although the two surface states are of different origin, i.e., topologically protected and trivial, respectively, both show strongly directional scattering properties and absence of backscattering. A comparison with ab initio calculations demonstrates that this is a direct consequence of their spin-momentum-locked spin texture which is found to exhibit an opposite rotational sense for the trivial state and the Dirac state.
Zhu, Jiayi; Yang, Xi; Fu, Zhibing; He, Junhui; Wang, Chaoyang; Wu, Weidong; Zhang, Lin
2016-02-12
A new, ultralight, superhigh surface area, multifunctional aerogel, which is macroassembled from sandwich-like, hierarchical, porous carbon/graphene nanosheets, is described. The multifunctional aerogel was characterized by means of XRD, SEM, TEM, Raman spectroscopy, and UV/Vis absorption spectroscopy. The multifunctional aerogel had an ultralow density of 8 mg cm(-3) and a superhigh surface area of 2650 m(2) g(-1) . The multifunctional aerogel was thermal stability and compressible. Meanwhile, the multifunctional aerogel exhibited high capacity for the adsorption of oils and organic solvents, unexpectedly high hydrogen adsorption and good electrochemical performance. PMID:26752085
Chen, Xu; Li, Jianjun; Wang, Enbo; Zhao, Qun; Kong, Zhan; Yuan, Xiangnan
2015-12-01
There is considerable interest in how the fate of adipose-derived stem cells is determined. Physical stimuli play a crucial role in skeletogenesis and in cartilage repair and regeneration. In the present study, we investigated the comparative and interactive effects of dynamic compression and SRY-related high-mobility group box gene-9 (SOX-9) on chondrogenesis of rabbit adipose-derived stem cells in three-dimensional gradual porous PLGA (polylactic-co-glycolic acid) composite scaffolds. Articular cartilage is stratified into zones delineated by characteristic changes in cellular, matrix, and nutritive components. As a consequence, biochemical and biomechanical properties vary greatly between the different zones, giving the tissue its unique structure and, thus, the ability to cope with extreme loading. The effects on development of the cartilage were examined using a combination of computational modeling to predict alterations in biophysical stimuli, detailed morphometric analysis of 3D digital representations. In addition, early chondrogenic differentiation was assessed via real-time PCR of mRNA expression levels for bone- and cartilage-specific gene markers. Our findings define the important role of dynamic compression combined with SOX-9 overexpression during in vitro generation of tissue-engineering cartilage and suggest that a 3D gradual porous PLGA composite scaffold may benefit articular cartilage tissue engineering in cartilage regeneration for better force distribution. PMID:26123537
NASA Astrophysics Data System (ADS)
Fang, Hongjian; Zhang, Haijiang; Yao, Huajian; Allam, Amir; Zigone, Dimitri; Ben-Zion, Yehuda; Thurber, Clifford; vanÂ derÂ Hilst, Robert D.
2016-05-01
We introduce a new algorithm for joint inversion of body wave and surface wave data to get better 3-D P wave (Vp) and S wave (Vs) velocity models by taking advantage of the complementary strengths of each data set. Our joint inversion algorithm uses a one-step inversion of surface wave traveltime measurements at different periods for 3-D Vs and Vp models without constructing the intermediate phase or group velocity maps. This allows a more straightforward modeling of surface wave traveltime data with the body wave arrival times. We take into consideration the sensitivity of surface wave data with respect to Vp in addition to its large sensitivity to Vs, which means both models are constrained by two different data types. The method is applied to determine 3-D crustal Vp and Vs models using body wave and Rayleigh wave data in the Southern California plate boundary region, which has previously been studied with both double-difference tomography method using body wave arrival times and ambient noise tomography method with Rayleigh and Love wave group velocity dispersion measurements. Our approach creates self-consistent and unique models with no prominent gaps, with Rayleigh wave data resolving shallow and large-scale features and body wave data constraining relatively deeper structures where their ray coverage is good. The velocity model from the joint inversion is consistent with local geological structures and produces better fits to observed seismic waveforms than the current Southern California Earthquake Center (SCEC) model.
Towing-tank and wind-tunnel measurements of the concentration distributions on the surface of a hill when a plume impinges from an upwind source are presented. The stability is varied between very stable and neutral. The results are compared with the theories developed in Part I....
Advancing three-dimensional MEMS by complimentary laser micro manufacturing
NASA Astrophysics Data System (ADS)
Palmer, Jeremy A.; Williams, John D.; Lemp, Tom; Lehecka, Tom M.; Medina, Francisco; Wicker, Ryan B.
2006-01-01
This paper describes improvements that enable engineers to create three-dimensional MEMS in a variety of materials. It also provides a means for selectively adding three-dimensional, high aspect ratio features to pre-existing PMMA micro molds for subsequent LIGA processing. This complimentary method involves in situ construction of three-dimensional micro molds in a stand-alone configuration or directly adjacent to features formed by x-ray lithography. Three-dimensional micro molds are created by micro stereolithography (MSL), an additive rapid prototyping technology. Alternatively, three-dimensional features may be added by direct femtosecond laser micro machining. Parameters for optimal femtosecond laser micro machining of PMMA at 800 nanometers are presented. The technical discussion also includes strategies for enhancements in the context of material selection and post-process surface finish. This approach may lead to practical, cost-effective 3-D MEMS with the surface finish and throughput advantages of x-ray lithography. Accurate three-dimensional metal microstructures are demonstrated. Challenges remain in process planning for micro stereolithography and development of buried features following femtosecond laser micro machining.
Estimating changes in lighting direction in binocularly viewed three-dimensional scenes
Gerhard, Holly E.; Maloney, Laurence T.
2010-01-01
We examine human ability to detect changes in scene lighting. Thirteen observers viewed three-dimensional rendered scenes stereoscopically. Each scene consisted of a randomly generated three-dimensional “Gaussian bump” surface rendered under a combination of collimated and diffuse light sources. During each trial, the collimated source underwent a small, quick change of position in one of four directions. The observer's task was to classify the direction of the lighting change. All observers were above chance in performing the task. We developed a model that combined two sources of information, a shape map and a shading map, to predict lighting change direction. We used this model to predict patterns of errors both across observers and across scenes differing in shape. We found that errors in estimating lighting direction were primarily the result of errors in representing surface shape. We characterized the surface features that affected performance in the classification task. PMID:21106676
Bzymek, Robert; Horsthemke, Markus; Isfort, Katrin; Mohr, Simon; Tjaden, Kerstin; Müller-Tidow, Carsten; Thomann, Marlies; Schwerdtle, Tanja; Bähler, Martin; Schwab, Albrecht; Hanley, Peter J.
2016-01-01
We recently found that macrophages from RhoA/RhoB double knockout mice had increased motility of the cell body, but severely impaired retraction of the tail and membrane extensions, whereas RhoA- or RhoB-deficient cells exhibited mild phenotypes. Here we extended this work and investigated the roles of Rho signaling in primary human blood monocytes migrating in chemotactic gradients and in various settings. Monocyte velocity, but not chemotactic navigation, was modestly dependent on Rho-ROCK-myosin II signaling on a 2D substrate or in a loose collagen type I matrix. Viewed by time-lapse epi-fluorescence microscopy, monocytes appeared to flutter rather than crawl, such that the 3D surface topology of individual cells was difficult to predict. Spinning disk confocal microscopy and 3D reconstruction revealed that cells move on planar surfaces and in a loose collagen matrix using prominent, curved planar protrusions, which are rapidly remodeled and reoriented, as well as resorbed. In a dense collagen type I matrix, there is insufficient space for this mode and cells adopt a highly Rho-dependent, lobular mode of motility. Thus, in addition to its role in tail retraction on 2D surfaces, Rho is critical for movement in confined spaces, but is largely redundant for motility and chemotaxis in loose matrices. PMID:27122054
Bzymek, Robert; Horsthemke, Markus; Isfort, Katrin; Mohr, Simon; Tjaden, Kerstin; Müller-Tidow, Carsten; Thomann, Marlies; Schwerdtle, Tanja; Bähler, Martin; Schwab, Albrecht; Hanley, Peter J
2016-01-01
We recently found that macrophages from RhoA/RhoB double knockout mice had increased motility of the cell body, but severely impaired retraction of the tail and membrane extensions, whereas RhoA- or RhoB-deficient cells exhibited mild phenotypes. Here we extended this work and investigated the roles of Rho signaling in primary human blood monocytes migrating in chemotactic gradients and in various settings. Monocyte velocity, but not chemotactic navigation, was modestly dependent on Rho-ROCK-myosin II signaling on a 2D substrate or in a loose collagen type I matrix. Viewed by time-lapse epi-fluorescence microscopy, monocytes appeared to flutter rather than crawl, such that the 3D surface topology of individual cells was difficult to predict. Spinning disk confocal microscopy and 3D reconstruction revealed that cells move on planar surfaces and in a loose collagen matrix using prominent, curved planar protrusions, which are rapidly remodeled and reoriented, as well as resorbed. In a dense collagen type I matrix, there is insufficient space for this mode and cells adopt a highly Rho-dependent, lobular mode of motility. Thus, in addition to its role in tail retraction on 2D surfaces, Rho is critical for movement in confined spaces, but is largely redundant for motility and chemotaxis in loose matrices. PMID:27122054
la Cour, L T; Stone, B W; Hopkins, W; Menzel, C; Fragaszy, Dorothy M
2014-01-01
Perceptuomotor functions that support using hand tools can be examined in other manipulation tasks, such as alignment of objects to surfaces. We examined tufted capuchin monkeys' and chimpanzees' performance at aligning objects to surfaces while managing one or two spatial relations to do so. We presented six subjects of each species with a single stick to place into a groove, two sticks of equal length to place into two grooves, or two sticks joined as a T to place into a T-shaped groove. Tufted capuchins and chimpanzees performed equivalently on these tasks, aligning the straight stick to within 22.5° of parallel to the groove in approximately half of their attempts to place it, and taking more attempts to place the T stick than two straight sticks. The findings provide strong evidence that tufted capuchins and chimpanzees do not reliably align even one prominent axial feature of an object to a surface, and that managing two concurrent allocentric spatial relations in an alignment problem is significantly more challenging to them than managing two sequential relations. In contrast, humans from 2 years of age display very different perceptuomotor abilities in a similar task: they align sticks to a groove reliably on each attempt, and they readily manage two allocentric spatial relations concurrently. Limitations in aligning objects and in managing two or more relations at a time significantly constrain how nonhuman primates can use hand tools. PMID:23820935
NASA Astrophysics Data System (ADS)
van der Hilst, R. D.; Zhang, H.; Maceira, M.; Chen, F.; Shen, W.; Fang, H.; Yao, H.
2014-12-01
To improve our understanding of the complex geological structure of continental China we need accurate depictions of the 3D structure of the crust and lithospheric mantle. Taking advantage of the increasingly dense seismograph coverage in continental China, several Vp and Vs models at various scales and resolutions have been obtained over the past decades. Tomographic models based either on body wave travel times or surface waves differ, however, in important aspects, especially for the structure beneath the Tibetan Plateau. Internally consistent Vp and Vs models are needed to resolve these differences. Body wave travel time tomography and surface wave tomography each have strengths and weaknesses. Travel time tomography can yield higher resolution in regions of dense path coverage, and it generally has excellent lateral resolution beneath regions of high seismic activity or dense station distribution. In many other regions, however, the shallow subsurface cannot be resolved adequately by direct P or S travel times. In contrast, surface wave data (from earthquakes or ambient noise) generally yields better radial resolution and has better potential for resolving shallow mantle structure beneath regions that are aseismic or which are void of seismograph stations. Gravity measurements can provide constraints on spatial variations in (mass) density, but like other potential field methods interpretation of gravity anomalies is plagued by substantial ambiguity. Indeed, weak and broad structures in the shallow subsurface can produce the same gravity signal (at the surface) as a small, strong density anomaly at a larger depth. To benefit from the complementary sampling of the different data, we have developed a joint inversion scheme that uses body wave travel times, surface wave dispersion, and satellite gravity data to invert for spatial variations in Vp, Vs, and mass density (with the seismic and gravity data linked through an
NASA Astrophysics Data System (ADS)
van der Hilst, R. D.; Zhang, H.; Maceira, M.; Chen, F.; Shen, W.; Fang, H.; Yao, H.
2015-12-01
To improve our understanding of the complex geological structure of continental China we need accurate depictions of the 3D structure of the crust and lithospheric mantle. Taking advantage of the increasingly dense seismograph coverage in continental China, several Vp and Vs models at various scales and resolutions have been obtained over the past decades. Tomographic models based either on body wave travel times or surface waves differ, however, in important aspects, especially for the structure beneath the Tibetan Plateau. Internally consistent Vp and Vs models are needed to resolve these differences. Body wave travel time tomography and surface wave tomography each have strengths and weaknesses. Travel time tomography can yield higher resolution in regions of dense path coverage, and it generally has excellent lateral resolution beneath regions of high seismic activity or dense station distribution. In many other regions, however, the shallow subsurface cannot be resolved adequately by direct P or S travel times. In contrast, surface wave data (from earthquakes or ambient noise) generally yields better radial resolution and has better potential for resolving shallow mantle structure beneath regions that are aseismic or which are void of seismograph stations. Gravity measurements can provide constraints on spatial variations in (mass) density, but like other potential field methods interpretation of gravity anomalies is plagued by substantial ambiguity. Indeed, weak and broad structures in the shallow subsurface can produce the same gravity signal (at the surface) as a small, strong density anomaly at a larger depth. To benefit from the complementary sampling of the different data, we have developed a joint inversion scheme that uses body wave travel times, surface wave dispersion, and satellite gravity data to invert for spatial variations in Vp, Vs, and mass density (with the seismic and gravity data linked through an
Three-Dimensional Reflectance Traction Microscopy
Jones, Christopher A. R.; Groves, Nicholas Scott; Sun, Bo
2016-01-01
Cells in three-dimensional (3D) environments exhibit very different biochemical and biophysical phenotypes compared to the behavior of cells in two-dimensional (2D) environments. As an important biomechanical measurement, 2D traction force microscopy can not be directly extended into 3D cases. In order to quantitatively characterize the contraction field, we have developed 3D reflectance traction microscopy which combines confocal reflection imaging and partial volume correlation postprocessing. We have measured the deformation field of collagen gel under controlled mechanical stress. We have also characterized the deformation field generated by invasive breast cancer cells of different morphologies in 3D collagen matrix. In contrast to employ dispersed tracing particles or fluorescently-tagged matrix proteins, our methods provide a label-free, computationally effective strategy to study the cell mechanics in native 3D extracellular matrix. PMID:27304456
Scaffolding for Three-Dimensional Embryonic Vasculogenesis
NASA Astrophysics Data System (ADS)
Kraehenbuehl, Thomas P.; Aday, Sezin; Ferreira, Lino S.
Biomaterial scaffolds have great potential to support efficient vascular differentiation of embryonic stem cells. Vascular cell fate-specific biochemical and biophysical cues have been identified and incorporated into three-dimensional (3D) biomaterials to efficiently direct embryonic vasculogenesis. The resulting vascular-like tissue can be used for regenerative medicine applications, further elucidation of biophysical and biochemical cues governing vasculogenesis, and drug discovery. In this chapter, we give an overview on the following: (1) developmental cues for directed differentiation of human embryonic stem cells (hESCs) into vascular cells, (2) 3D vascular differentiation in embryoid bodies (EBs), (3) preparation of 3D scaffolds for the vascular differentiation of hESCs, and (4) the most significant studies combining scaffolding and hESCs for development of vascular-like tissue.
Three dimensional thrust chamber life prediction
NASA Technical Reports Server (NTRS)
Armstrong, W. H.; Brogren, E. W.
1976-01-01
A study was performed to analytically determine the cyclic thermomechanical behavior and fatigue life of three configurations of a Plug Nozzle Thrust Chamber. This thrust chamber is a test model which represents the current trend in nozzle design calling for high performance coupled with weight and volume limitations as well as extended life for reusability. The study involved the use of different materials and material combinations to evaluate their application to the problem of low-cycle fatigue in the thrust chamber. The thermal and structural analyses were carried out on a three-dimensional basis. Results are presented which show plots of continuous temperature histories and temperature distributions at selected times during the operating cycle of the thrust chamber. Computed structural data show critical regions for low-cycle fatigue and the histories of strain within the regions for each operation cycle.
Abdulkarim, Muthanna; Agulló, Nuria; Cattoz, Beatrice; Griffiths, Peter; Bernkop-Schnürch, Andreas; Borros, Salvador Gómez; Gumbleton, Mark
2015-11-01
Multiple particle tracking (MPT) methodology was used to dissect the impact of nanoparticle surface charge and size upon particle diffusion through freshly harvested porcine jejunum mucus. The mucus was characterised rheologically and by atomic force microscopy. To vary nanoparticle surface charge we used a series of self-assembly polyelectrolyte particles composed of varying ratios of the negatively charged polyacrylic acid polymer and the positively charged chitosan polymer. This series included a neutral or near-neutral particle to correspond to highly charged but near-neutral viral particles that appear to effectively permeate mucus. In order to negate the confounding issue of self-aggregation of such neutral synthetic particles a sonication step effectively reduced particle size (to less than 340 nm) for a sufficient period to conduct the tracking experiments. Across the polyelectrolyte particles a broad and meaningful relationship was observed between particle diffusion in mucus (×1000 difference between slowest and fastest particle types), particle size (104-373 nm) and particle surface charge (-29 mV to +19.5 mV), where the beneficial characteristic promoting diffusion was a neutral or near-neutral charge. The diffusion of the neutral polyelectrolyte particle (0.02887 cm S(-1)×10(-9)) compared favourably with that of a highly diffusive PEGylated-PLGA particle (0.03182 cm(2) S(-1)×10(-9)), despite the size of the latter (54 nm diameter) accommodating a reduced steric hindrance with the mucin network. Heterogeneity of particle diffusion within a given particle type revealed the most diffusive 10% sub-population for the neutral polyelectrolyte formulation (5.809 cm(2) S(-1)×10(-9)) to be faster than that of the most diffusive 10% sub-populations obtained either for the PEGylated-PLGA particle (4.061 cm(2) S(-1)×10(-9)) or for a capsid adenovirus particle (1.922 cm(2) S(-1)×10(-9)). While this study has used a simple self-assembly polyelectrolyte system
Three-dimensional boundary layers approaching separation
NASA Technical Reports Server (NTRS)
Williams, J. C., III
1976-01-01
The theory of semi-similar solutions of the laminar boundary layer equations is applied to several flows in which the boundary layer approaches a three-dimensional separation line. The solutions obtained are used to deduce the nature of three-dimensional separation. It is shown that in these cases separation is of the "ordinary" type. A solution is also presented for a case in which a vortex is embedded within the three-dimensional boundary layer.
Guyomarc'h, Pierre; Santos, Frédéric; Dutailly, Bruno; Desbarats, Pascal; Bou, Christophe; Coqueugniot, Hélène
2012-06-10
Digital investigation of anthropological material through computed tomography (CT) offers several new opportunities in morphometrics. However, an object measured with computer-assisted methods does not necessarily exactly match the original one. The scanning and surface reconstruction of the object induce some alterations, and data acquisition is prone to measurement uncertainty. The purpose of this research is to evaluate the intra- and inter-observers variations in medical CT scan measurements of a known-size phantom and two dry crania. Two software packages, AMIRA and Treatment and Increased Vision for Medical Imaging (TIVMI), which use different techniques of surface reconstructions, were compared. The mean difference between the measurements was lower for TIVMI, using an objective algorithm based on the half-maximum height (HMH) protocol in three dimensions (3D). AMIRA can induce up to a 4% error in known measurements and 5% uncertainty in dry skull measurements. This study emphasises the risk of object shape alteration in each step of its digitisation. PMID:22297143
Green, Daniel; Pace, Suzi; Curtis, Suzanne M; Sakowska, Magdalena; Lamb, Graham D; Dulhunty, Angela F; Casarotto, Marco G
2003-01-01
An alpha-helical II-III loop segment of the dihydropyridine receptor activates the ryanodine receptor calcium-release channel. We describe a novel manipulation in which this agonist's activity is increased by modifying its surface structure to resemble that of a toxin molecule. In a unique system, native beta-sheet scorpion toxins have been reported to activate skeletal muscle ryanodine receptor calcium channels with high affinity by binding to the same site as the lower-affinity alpha-helical dihydropyridine receptor segment. We increased the alignment of basic residues in the alpha-helical peptide to mimic the spatial orientation of active residues in the scorpion toxin, with a consequent 2-20-fold increase in the activity of the alpha-helical peptide. We hypothesized that, like the native peptide, the modified peptide and the scorpion toxin may bind to a common site. This was supported by (i) similar changes in ryanodine receptor channel gating induced by the native or modified alpha-helical peptide and the beta-sheet toxin, a 10-100-fold reduction in channel closed time, with a < or = 2-fold increase in open dwell time and (ii) a failure of the toxin to further activate channels activated by the peptides. These results suggest that diverse structural scaffolds can present similar conformational surface properties to target common receptor sites. PMID:12429019
Modelling of Three-Dimensional Nanographene.
Mathioudakis, Christos; Kelires, Pantelis C
2016-12-01
Monte Carlo simulations and tight-binding calculations shed light on the properties of three-dimensional nanographene, a material composed of interlinked, covalently-bonded nanoplatelet graphene units. By constructing realistic model networks of nanographene, we study its structure, mechanical stability, and optoelectronic properties. We find that the material is nanoporous with high specific surface area, in agreement with experimental reports. Its structure is characterized by randomly oriented and curved nanoplatelet units which retain a high degree of graphene order. The material exhibits good mechanical stability with a formation energy of only ∼0.3 eV/atom compared to two-dimensional graphene. It has high electrical conductivity and optical absorption, with values approaching those of graphene. PMID:26983431
Heterogeneous, three-dimensional texturing of graphene.
Wang, Michael Cai; Chun, SungGyu; Han, Ryan Steven; Ashraf, Ali; Kang, Pilgyu; Nam, SungWoo
2015-03-11
We report a single-step strategy to achieve heterogeneous, three-dimensional (3D) texturing of graphene and graphite by using a thermally activated shape-memory polymer substrate. Uniform arrays of graphene crumples can be created on the centimeter scale by controlling simple thermal processing parameters without compromising the electrical properties of graphene. In addition, we show the capability to selectively pattern crumples from otherwise flat graphene and graphene/graphite in a localized manner, which has not been previously achievable using other methods. Finally, we demonstrate 3D crumpled graphene field-effect transistor arrays in a solution-gated configuration. The presented approach has the capability to conform onto arbitrary 3D surfaces, a necessary prerequisite for adaptive electronics, and will enable facile large-scale topography engineering of not only graphene but also other thin-film and 2D materials in the future. PMID:25667959
Towards microscale electrohydrodynamic three-dimensional printing
NASA Astrophysics Data System (ADS)
He, Jiankang; Xu, Fangyuan; Cao, Yi; Liu, Yaxiong; Li, Dichen
2016-02-01
It is challenging for the existing three-dimensional (3D) printing techniques to fabricate high-resolution 3D microstructures with low costs and high efficiency. In this work we present a solvent-based electrohydrodynamic 3D printing technique that allows fabrication of microscale structures like single walls, crossed walls, lattice and concentric circles. Process parameters were optimized to deposit tiny 3D patterns with a wall width smaller than 10 μm and a high aspect ratio of about 60. Tight bonding among neighbour layers could be achieved with a smooth lateral surface. In comparison with the existing microscale 3D printing techniques, the presented method is low-cost, highly efficient and applicable to multiple polymers. It is envisioned that this simple microscale 3D printing strategy might provide an alternative and innovative way for application in MEMS, biosensor and flexible electronics.
Ordered three-dimensional interconnected nanoarchitectures in anodic porous alumina
Martín, Jaime; Martín-González, Marisol; Fernández, Jose Francisco; Caballero-Calero, Olga
2014-01-01
Three-dimensional nanostructures combine properties of nanoscale materials with the advantages of being macro-sized pieces when the time comes to manipulate, measure their properties, or make a device. However, the amount of compounds with the ability to self-organize in ordered three-dimensional nanostructures is limited. Therefore, template-based fabrication strategies become the key approach towards three-dimensional nanostructures. Here we report the simple fabrication of a template based on anodic aluminum oxide, having a well-defined, ordered, tunable, homogeneous 3D nanotubular network in the sub 100 nm range. The three-dimensional templates are then employed to achieve three-dimensional, ordered nanowire-networks in Bi2Te3 and polystyrene. Lastly, we demonstrate the photonic crystal behavior of both the template and the polystyrene three-dimensional nanostructure. Our approach may establish the foundations for future high-throughput, cheap, photonic materials and devices made of simple commodity plastics, metals, and semiconductors. PMID:25342247
NASA Astrophysics Data System (ADS)
Iwaki, Sunao; Sutani, Kouichi
2010-05-01
Here, we present a system to visualize (i) the distribution of magnetoencephalographic (MEG) signal strength in the subject-specific measurement settings predicted by a realistic MEG signal generation model (forward model) and previously published results that are typically presented in the standardized brain coordinates, and (ii) the distribution of the sensitivity of arbitrary selected group of MEG sensors on the subject-specific cortical surface. The current results suggest that (a) our methods to predict MEG field distribution from a priori information about the possible "active" cortical regions obtained from standardized functional magnetic resonance imaging results are useful for determining the sensor sets of interest in the MEG studies for a specific subject under specific measurement condition, and that (b) visualization of the sensitivity of sensor groups could provide the approximate distribution of the MEG sources without solving the MEG inverse problem.
Three-dimensional reconstruction for high-speed volume measurement
NASA Astrophysics Data System (ADS)
Lee, Dah-Jye; Lane, Robert M.; Chang, Guang-Hwa
2001-02-01
Volume measurement is an important process for various industries such as food processing, fruit and vegetable grading, etc. Value or price is often determined by the size of product. In seafood industry, for example, oyster meat is separated into four grades before being packaged. Large size grade means higher selling price than small size. More consistent packaging size is also an indication of high quality. Product size can be measured optically with machine vision technology for on-line inspection and grading systems. Most optical grading techniques use a two-dimensional area projection or the weight of the product to estimate the actual product volume. These methods are subject to measurement inaccuracy because of the missing thickness information. An algorithm combines laser triangulation technique with two-dimensional measurement to reconstruct a three-dimensional surface for volume measurement is introduced in this paper. The result of this technique shows a significant accuracy improvement from the area-projection method
Three-dimensional graphene-based composites for energy applications
NASA Astrophysics Data System (ADS)
Mao, Shun; Lu, Ganhua; Chen, Junhong
2015-04-01
Three-dimensional (3D) graphene-based composites have drawn increasing attention for energy applications due to their unique structures and properties. By combining the merits of 3D graphene (3DG), e.g., a porous and interconnected network, a high electrical conductivity, a large accessible surface area, and excellent mechanical strength and thermal stability, with the high chemical/electrochemical activities of active materials, 3DG-based composites show great promise as high-performance electrode materials in various energy devices. This article reviews recent progress in 3DG-based composites and their applications in energy storage/conversion devices, i.e., supercapacitors, lithium-ion batteries, dye-sensitized solar cells, and fuel cells.
Clustering-based robust three-dimensional phase unwrapping algorithm.
Arevalillo-Herráez, Miguel; Burton, David R; Lalor, Michael J
2010-04-01
Relatively recent techniques that produce phase volumes have motivated the study of three-dimensional (3D) unwrapping algorithms that inherently incorporate the third dimension into the process. We propose a novel 3D unwrapping algorithm that can be considered to be a generalization of the minimum spanning tree (MST) approach. The technique combines characteristics of some of the most robust existing methods: it uses a quality map to guide the unwrapping process, a region growing mechanism to progressively unwrap the signal, and also cut surfaces to avoid error propagation. The approach has been evaluated in the context of noncontact measurement of dynamic objects, suggesting a better performance than MST-based approaches. PMID:20357860
Three-dimensional THz lumped-circuit resonators.
Todorov, Yanko; Desfond, Pascal; Belacel, Cherif; Becerra, Loïc; Sirtori, Carlo
2015-06-29
Our work describes a novel three dimensional meta-material resonator design for optoelectronic applications in the THz spectral range. In our resonant circuits, the capacitors are formed by double-metal regions cladding a dielectric core. Unlike conventional planar metamaterials, the electric field is perpendicular to the surface and totally confined in the dielectric core. Furthermore, the magnetic field, confined in the inductive part, is parallel to the electric field, ruling out coupling through propagation effects. Our geometry thus combines the benefit of double-metal structures that provide parallel plate capacitors, while maintaining the ability of meta-material resonators to adjust independently the capacitive and inductive parts. Furthermore, in our geometry, a constant bias can be applied across the dielectric, making these resonators very suitable for applications such as ultra-low dark current THz quantum detectors and amplifiers based on quantum cascade gain medium. PMID:26191695
Boundary Integral Solutions to Three-Dimensional Unconfined Darcy's Flow
NASA Astrophysics Data System (ADS)
Lennon, Gerard P.; Liu, Philip L.-F.; Liggett, James A.
1980-08-01
The boundary integral equation method (BIEM) is used to solve three-dimensional potential flow problems in porous media. The problems considered here are time dependent and have a nonlinear boundary condition on the free surface. The entire boundary, including the moving free surface, discretized into linear finite elements for the purpose of evaluating the boundary integrals. The technique allows transient, three-dimensional problems to be solved with reasonable computational costs. Numerical examples include recharge through rectangular and circular areas and seepage flow from a surface pond. The examples are used to illustrate the method and show the nonlinear effects.
Dakua, Sarada Prasad; Abinahed, Julien; Al-Ansari, Abdulla
2015-01-01
Abstract. Liver segmentation continues to remain a major challenge, largely due to its intense complexity with surrounding anatomical structures (stomach, kidney, and heart), high noise level and lack of contrast in pathological computed tomography (CT) data. We present an approach to reconstructing the liver surface in low contrast CT. The main contributions are: (1) a stochastic resonance-based methodology in discrete cosine transform domain is developed to enhance the contrast of pathological liver images, (2) a new formulation is proposed to prevent the object boundary, resulting from the cellular automata method, from leaking into the surrounding areas of similar intensity, and (3) a level-set method is suggested to generate intermediate segmentation contours from two segmented slices distantly located in a subject sequence. We have tested the algorithm on real datasets obtained from two sources, Hamad General Hospital and medical image computing and computer-assisted interventions grand challenge workshop. Various parameters in the algorithm, such as w, Δt, z, α, μ, α1, and α2, play imperative roles, thus their values are precisely selected. Both qualitative and quantitative evaluation performed on liver data show promising segmentation accuracy when compared with ground truth data reflecting the potential of the proposed method. PMID:26158101
NASA Astrophysics Data System (ADS)
Li, Hui; Pei, Yong; Zeng, Xiao Cheng
2010-10-01
We investigate the possible structural transition of a planar Au10 cluster during its soft landing on a TiO2 (110) surface with or with no oxygen defects. The collision between the gold cluster and the oxide surface is simulated using the Car-Parrinello quantum molecular dynamics method. Both high-speed and low-speed conditions typically implemented in soft-landing experiments are simulated. It is found that under a high-speed condition, the gold cluster Au10 can undergo a sequence of structural transitions after colliding with a defect-free TiO2 (110) surface. When the TiO2 (110) surface possesses oxygen vacancies, however, chemical bonds can form between gold and Ti atoms if gold atoms contact directly with the vacancies. As a consequence, one oxygen vacancy is capable of trapping one Au atom, and thus can split the Au10 into two parts while bouncing back from the surface. In addition, we study reaction pathways for the CO oxidation based on three isomer structures of Au10 observed in the soft-landing simulation: (1) the precollision two-dimensional structure, (2) a postcollision three-dimensional (3D) structure, and (3) an intermediate (transient) 3D structure that appeared in the midst of the collision. This study allows us to examine the structure-activity relationship using the Au10 as a prototype model catalyst.
Rapid three-dimensional segmentation of the carotid bifurcation from serial MR images.
Ladak, H M; Milner, J S; Steinman, D A
2000-02-01
The current trend in computational hemodynamics is to employ realistic models derived from ex vivo or in vivo imaging. Such studies typically produce a series of images from which the lumen boundaries must first be individually extracted (i.e., two-dimensional segmentation), and then serially reconstructed to produce the three-dimensional lumen surface geometry. In this paper, we present a rapid three-dimensional segmentation technique that combines these two steps, based on the idea of an expanding virtual balloon. This three-dimensional technique is demonstrated in application to finite element meshing and CFD modeling of flow in the carotid bifurcation of a normal volunteer imaged with black blood MRI. Wall shear stress patterns computed using a mesh generated with the three-dimensional technique agree well with those computed using a mesh generated from conventional two-dimensional segmentation and serial reconstruction. In addition to reducing the time required to extract the lumen surface from hours to minutes, our approach is easy to learn and use and requires minimal user intervention, which can potentially increase the accuracy and precision of quantitative and longitudinal studies of hemodynamics and vascular disease. PMID:10790835
View Factor Calculation for Three-Dimensional Geometries.
Energy Science and Technology Software Center (ESTSC)
1989-06-20
Version 00 MCVIEW calculates the radiation geometric view factor between surfaces for three dimensional geometries with and without interposed third surface obstructions. It was developed to calculate view factors for input data to heat transfer analysis programs such as SCA-03/TRUMP, SCA-01/HEATING-5 and PSR-199/HEATING-6.
Three Dimensional Imaging with Multiple Wavelength Speckle Interferometry
Bernacki, Bruce E.; Cannon, Bret D.; Schiffern, John T.; Mendoza, Albert
2014-05-28
We present the design, modeling, construction, and results of a three-dimensional imager based upon multiple-wavelength speckle interferometry. A surface under test is illuminated with tunable laser light in a Michelson interferometer configuration while a speckled image is acquired at each laser frequency step. The resulting hypercube is Fourier transformed in the frequency dimension and the beat frequencies that result map the relative offsets of surface features. Synthetic wavelengths resulting from the laser tuning can probe features ranging from 18 microns to hundreds of millimeters. Three dimensional images will be presented along with modeling results.
Li Bin; Han Keli
2008-03-21
A theoretical investigation on the nonadiabatic processes of the full three-dimensional D{sup +}+H{sub 2} and H{sup +}+D{sub 2} reaction systems has been performed by using trajectory surface hopping (TSH) method based on the Zhu-Nakamura (ZN) theory. This ZN-TSH method refers to not only classically allowed hops but also classically forbidden hops. The potential energy surface constructed by Kamisaka et al. is employed in the calculation. A new iterative method is proposed to yield the two-dimensional seam surface from the topography of the adiabatic potential surfaces, in which the inconvenience of directly solving the first-order partial differential equation is avoided. The cross sections of these two systems are calculated for three competing channels of the reactive charge transfer, the nonreactive charge transfer, and the reactive noncharge transfer, for ground rovibrational state of H{sub 2} or D{sub 2}. Also, this study provides reaction probabilities of these three processes for the total angular momentum J=0 and ground initial vibrational state of H{sub 2} or D{sub 2}. The calculated results from ZN-TSH method are in good agreement with the exact quantum calculations and the experimental measurements.
Three-Dimensional Contour Maps
ERIC Educational Resources Information Center
Lee, Edward
2005-01-01
In summary, this highly conceptual activity helps middle school students understand that the lines on the contour map represent intersections of the surface of the landform with regularly spaced horizontal planes. Building the landform and relating its features to the contour map offer many opportunities for visualization, all grounded in concrete…
Three dimensional characterization and archiving system
Sebastian, R.L.; Clark, R.; Gallman, P.
1996-04-01
The Three Dimensional Characterization and Archiving System (3D-ICAS) is being developed as a remote system to perform rapid in situ analysis of hazardous organics and radionuclide contamination on structural materials. Coleman Research and its subcontractors, Thermedics Detection, Inc. (TD) and the University of Idaho (UI) are in the second phase of a three phase program to develop 3D-ICAS to support Decontamination and Decommissioning (D and D) operations. Accurate physical characterization of surfaces and the radioactive and organic is a critical D and D task. Surface characterization includes identification of potentially dangerous inorganic materials, such as asbestos and transite. Real-time remotely operable characterization instrumentation will significantly advance the analysis capabilities beyond those currently employed. Chemical analysis is a primary area where the characterization process will be improved. The 3D-ICAS system robotically conveys a multisensor probe near the surfaces to be inspected. The sensor position and orientation are monitored and controlled using coherent laser radar (CLR) tracking. The CLR also provides 3D facility maps which establish a 3D world view within which the robotic sensor system can operate.
Three-dimensional charge coupled device
Conder, Alan D.; Young, Bruce K. F.
1999-01-01
A monolithic three dimensional charged coupled device (3D-CCD) which utilizes the entire bulk of the semiconductor for charge generation, storage, and transfer. The 3D-CCD provides a vast improvement of current CCD architectures that use only the surface of the semiconductor substrate. The 3D-CCD is capable of developing a strong E-field throughout the depth of the semiconductor by using deep (buried) parallel (bulk) electrodes in the substrate material. Using backside illumination, the 3D-CCD architecture enables a single device to image photon energies from the visible, to the ultra-violet and soft x-ray, and out to higher energy x-rays of 30 keV and beyond. The buried or bulk electrodes are electrically connected to the surface electrodes, and an E-field parallel to the surface is established with the pixel in which the bulk electrodes are located. This E-field attracts charge to the bulk electrodes independent of depth and confines it within the pixel in which it is generated. Charge diffusion is greatly reduced because the E-field is strong due to the proximity of the bulk electrodes.
Collimation and Stability of Three Dimensional Jets
NASA Astrophysics Data System (ADS)
Hardee, P. E.; Clarke, D. A.; Howell, D. A.
1993-12-01
Three-dimensional numerical simulations of cylindrical jets established in equilibrium with a surrounding uniform medium have been performed. Large scale structures such as helical twisting of the jet, elliptical distortion and bifurcation of the jet, and triangular distortion and trifurcation of the jet have been seen in the simulations. The grid resolution has been sufficient to allow the development of structures on smaller scales and has revealed higher order distortions of the jet surface and complex structure internal to the jet. However, smaller scale surface distortion and internal jet structure do not significantly modify the large scale dynamics. It is the large scale surface distortions and accompanying filamentation that dominate the jet dynamics. Decollimation occurs as the jet bifurcates or trifurcates. Jets with density less than the immediately surrounding medium rapidly decollimate and expand as the jet filaments into multiple streams leading to shock heating and mass entrainment. The resulting morphology resembles a turbulent plume and might be relevant to some FRI type radio sources. Jet densities higher than the immediately surrounding medium are required to produce FRII type radio source jet morphology and protostellar jet morphology. Thus, while jets may be denser or lighter than the external medium through which they propagate, it is the conditions in the cocoon or lobe around the jet that governs the dynamics far behind the jet front. This work was supported by NSF grant AST-8919180, EPSCoR grant EHR-9108761 and NSF-REU grant AST-9300413.
Magnetic resonance force microscopy combined with surface topography
NASA Astrophysics Data System (ADS)
Tsuji, S.; Yoshinari, Y.; Kawai, E.; Nakajima, K.; Park, H. S.; Shindo, D.
2007-10-01
A new method of surface microscopy is proposed, which combines three-dimensional electron spin resonance imaging by magnetic resonance force microscopy (MRFM) and topographic imaging of the sample surface by scanning force microscopy (SFM). In order to demonstrate its potential for the identification of microscale objects, the individual and combined images are used to provide the locations, shapes and spin density distributions of target phantom objects. We report spatial resolution in MRFM of 2.8 × 2.8 × 2.0μm 3. This could be improved to the theoretical limit of 0.08 × 0.08 × 0.04μm 3 through reduction of the thermal noise by cooling to cryogenic temperatures ˜0.5 K. We believe that this type of microscopy will become a very useful tool for the investigation of anomalies induced in surfaces by materials buried below the surface.
Ando, Takamasa; Horisaki, Ryoichi; Tanida, Jun
2015-08-20
We propose a method for visualizing three-dimensional objects in scattering media. Our method is based on active illumination using three-dimensionally coded patterns and a numerical algorithm employing a sparsity constraint. We experimentally demonstrated the proposed imaging method for test charts located three-dimensionally at different depths in the space behind a translucent sheet. PMID:26368767
Three Dimensional Illustrating--Three-Dimensional Vision and Deception of Sensibility
ERIC Educational Resources Information Center
Szállassy, Noémi; Gánóczy, Anita; Kriska, György
2009-01-01
The wide-spread digital photography and computer use gave the opportunity for everyone to make three-dimensional pictures and to make them public. The new opportunities with three-dimensional techniques give chance for the birth of new artistic photographs. We present in detail the biological roots of three-dimensional visualization, the phenomena…
El-Shenawee, M; Rappaport, C; Silevitch, M
2001-12-01
We present a statistical study of the electric field scattered from a three-dimensional penetrable object buried under a two-dimensional random rough surface. Monte Carlo simulations using the steepest-descent fast multipole method (SDFMM) are conducted to calculate the average and the standard deviation of the near-zone scattered fields. The SDFMM, originally developed at the University of Illinois at Urbana-Champaign, has been modified to calculate the unknown surface currents both on the rough ground and on the buried object that are due to excitation by a tapered Gaussian beam. The rough ground medium used is an experimentally measured typical dry Bosnian soil with 3.8% moisture, while the buried object represents a plastic land mine modeled as an oblate spheroid with dimensions and burial depth smaller than the free-space wavelength. Both vertical and horizontal polarizations for the incident waves are studied. The numerical results show that the TNT mine signature is almost 5% of the total field scattered from the ground. Moreover, relatively recognizable object signatures are observed even when the object is buried under the tail of the incident beam. Interestingly, even for the small surface roughness parameters considered, the standard deviation of the object signature is almost 30% of the signal itself, indicating significant clutter distortion that is due to the roughness of the ground. PMID:11760205
NASA Astrophysics Data System (ADS)
Hattori, Ken; Oi, Hideo; Tanaka, Kota; Kumagai, Tomohiro; Daimon, Hiroshi
2012-05-01
We have applied a three-dimensional (3D) reciprocal-lattice analysis method using a typical reflection high-energy electron diffraction (RHEED) system - all RHEED patterns in scanning sample-surface azimuth are converted into 3D reciprocal-lattice space. This analysis method can determine complex crystal orientations of nanoclusters, islands, and grains with multiple domains, which are difficult to obtain from a small number of non-converted two-dimensional RHEED patterns. For an Al-deposited Si(111) surface followed by annealing, we successfully determined new crystal orientations of Al grains: Al(001), Al(012) and Al(011) ∥ Si(111) with Al[100] ∥ Si<0bar 11>. The typical acquisition time of 3D RHEED patterns is 10-20 min, which is shorter than that by a standard X-ray diffraction system with φ and ω scans for 3D reciprocal-lattice mapping. This is one of the advantages of this analysis method, in addition to the convenient observation of in situ vacuum-fabricated nanocrystals on substrate surfaces with high sensitivity.
Automatic creation of three-dimensional avatars
NASA Astrophysics Data System (ADS)
Villa-Uriol, Maria-Cruz; Sainz, Miguel; Kuester, Falko; Bagherzadeh, Nader
2003-01-01
Highly accurate avatars of humans promise a new level of realism in engineering and entertainment applications, including areas such as computer animated movies, computer game development interactive virtual environments and tele-presence. In order to provide high-quality avatars, new techniques for the automatic acquisition and creation are required. A framework for the capture and construction of arbitrary avatars from image data is presented in this paper. Avatars are automatically reconstructed from multiple static images of a human subject by utilizing image information to reshape a synthetic three-dimensional articulated reference model. A pipeline is presented that combines a set of hardware-accelerated stages into one seamless system. Primary stages in this pipeline include pose estimation, skeleton fitting, body part segmentation, geometry construction and coloring, leading to avatars that can be animated and included into interactive environments. The presented system removes traditional constraints in the initial pose of the captured subject by using silhouette-based modification techniques in combination with a reference model. Results can be obtained in near-real time with very limited user intervention.
Three dimensional living neural networks
NASA Astrophysics Data System (ADS)
Linnenberger, Anna; McLeod, Robert R.; Basta, Tamara; Stowell, Michael H. B.
2015-08-01
We investigate holographic optical tweezing combined with step-and-repeat maskless projection micro-stereolithography for fine control of 3D positioning of living cells within a 3D microstructured hydrogel grid. Samples were fabricated using three different cell lines; PC12, NT2/D1 and iPSC. PC12 cells are a rat cell line capable of differentiation into neuron-like cells NT2/D1 cells are a human cell line that exhibit biochemical and developmental properties similar to that of an early embryo and when exposed to retinoic acid the cells differentiate into human neurons useful for studies of human neurological disease. Finally induced pluripotent stem cells (iPSC) were utilized with the goal of future studies of neural networks fabricated from human iPSC derived neurons. Cells are positioned in the monomer solution with holographic optical tweezers at 1064 nm and then are encapsulated by photopolymerization of polyethylene glycol (PEG) hydrogels formed by thiol-ene photo-click chemistry via projection of a 512x512 spatial light modulator (SLM) illuminated at 405 nm. Fabricated samples are incubated in differentiation media such that cells cease to divide and begin to form axons or axon-like structures. By controlling the position of the cells within the encapsulating hydrogel structure the formation of the neural circuits is controlled. The samples fabricated with this system are a useful model for future studies of neural circuit formation, neurological disease, cellular communication, plasticity, and repair mechanisms.
Primary and Secondary Three Dimensional Microbatteries
NASA Astrophysics Data System (ADS)
Cirigliano, Nicolas
Today's MEMS devices are limited more so by the batteries that supply their power than the fabrication methods used to build them. Thick battery electrodes are capable of providing adequate energy, but long and tortuous diffusion pathways lead to low power capabilities. On the other hand, thin film batteries can operate at significant current densities but require large surface areas to supply practical energy. This dilemma can be solved by either developing new high capacity materials or by engineering new battery designs that decouple power and energy. Three dimensional batteries redesign traditional configurations to create nonplanar interfaces between battery components. This can be done by introducing hierarchical structures into the electrode shape. Designs such as these provide a maximum surface area over which chemical reactions can occur. Furthermore, by maintaining small feature sizes, ion diffusion and electronic transport distances can remain minimal. Manipulating these properties ensures fast kinetics that are required for high power situations. Energy density is maximized by layering material in the vertical direction, thus ensuring a minimal footprint area. Three dimensional carbon electrodes are fabricated using basic MEMS techniques. A silicon mold is anisotropically etched to produce channels of a predetermined diameter. The channels are then filled using an infiltration technique with electrode slurry. Once dried, the mold is attached to a current collector and etched using a XeF2 process. Electrodes of varying feature sizes have been fabricated using this method with aspect ratios ranging from 3.5:1 to 7:1. 3D carbon electrodes are shown to obtain capacities over 8 mAh/cm2 at 0.1 mA/cm2, or nearly 700% higher than planar carbon electrodes. When assembled with a planar cathode, the battery cell produced an average discharge capacity of 40 J/cm 2 at a current density of 0.2 mA/cm2. This places the energy density values slightly less than thick
A moving observer in a three-dimensional world
2016-01-01
For many tasks such as retrieving a previously viewed object, an observer must form a representation of the world at one location and use it at another. A world-based three-dimensional reconstruction of the scene built up from visual information would fulfil this requirement, something computer vision now achieves with great speed and accuracy. However, I argue that it is neither easy nor necessary for the brain to do this. I discuss biologically plausible alternatives, including the possibility of avoiding three-dimensional coordinate frames such as ego-centric and world-based representations. For example, the distance, slant and local shape of surfaces dictate the propensity of visual features to move in the image with respect to one another as the observer's perspective changes (through movement or binocular viewing). Such propensities can be stored without the need for three-dimensional reference frames. The problem of representing a stable scene in the face of continual head and eye movements is an appropriate starting place for understanding the goal of three-dimensional vision, more so, I argue, than the case of a static binocular observer. This article is part of the themed issue ‘Vision in our three-dimensional world’. PMID:27269608
Three-dimensional magnetospheric equilibrium with isotropic pressure
Cheng, C.Z.
1995-05-01
In the absence of the toroidal flux, two coupled quasi two-dimensional elliptic equilibrium equations have been derived to describe self-consistent three-dimensional static magnetospheric equilibria with isotropic pressure in an optimal ({Psi},{alpha},{chi}) flux coordinate system, where {Psi} is the magnetic flux function, {chi} is a generalized poloidal angle, {alpha} is the toroidal angle, {alpha} = {phi} {minus} {delta}({Psi},{phi},{chi}) is the toroidal angle, {delta}({Psi},{phi},{chi}) is periodic in {phi}, and the magnetic field is represented as {rvec B} = {del}{Psi} {times} {del}{alpha}. A three-dimensional magnetospheric equilibrium code, the MAG-3D code, has been developed by employing an iterative metric method. The main difference between the three-dimensional and the two-dimensional axisymmetric solutions is that the field-aligned current and the toroidal magnetic field are finite for the three-dimensional case, but vanish for the two-dimensional axisymmetric case. With the same boundary flux surface shape, the two-dimensional axisymmetric results are similar to the three-dimensional magnetosphere at each local time cross section.
A moving observer in a three-dimensional world.
Glennerster, Andrew
2016-06-19
For many tasks such as retrieving a previously viewed object, an observer must form a representation of the world at one location and use it at another. A world-based three-dimensional reconstruction of the scene built up from visual information would fulfil this requirement, something computer vision now achieves with great speed and accuracy. However, I argue that it is neither easy nor necessary for the brain to do this. I discuss biologically plausible alternatives, including the possibility of avoiding three-dimensional coordinate frames such as ego-centric and world-based representations. For example, the distance, slant and local shape of surfaces dictate the propensity of visual features to move in the image with respect to one another as the observer's perspective changes (through movement or binocular viewing). Such propensities can be stored without the need for three-dimensional reference frames. The problem of representing a stable scene in the face of continual head and eye movements is an appropriate starting place for understanding the goal of three-dimensional vision, more so, I argue, than the case of a static binocular observer.This article is part of the themed issue 'Vision in our three-dimensional world'. PMID:27269608
Multifunctional, three-dimensional tomography for analysis of eletrectrohydrodynamic jetting
NASA Astrophysics Data System (ADS)
Nguyen, Xuan Hung; Gim, Yeonghyeon; Ko, Han Seo
2015-05-01
A three-dimensional optical tomography technique was developed to reconstruct three-dimensional objects using a set of two-dimensional shadowgraphic images and normal gray images. From three high-speed cameras, which were positioned at an offset angle of 45° between each other, number, size, and location of electrohydrodynamic jets with respect to the nozzle position were analyzed using shadowgraphic tomography employing multiplicative algebraic reconstruction technique (MART). Additionally, a flow field inside a cone-shaped liquid (Taylor cone) induced under an electric field was observed using a simultaneous multiplicative algebraic reconstruction technique (SMART), a tomographic method for reconstructing light intensities of particles, combined with three-dimensional cross-correlation. Various velocity fields of circulating flows inside the cone-shaped liquid caused by various physico-chemical properties of liquid were also investigated.
Acoustic propagation in rigid three-dimensional waveguides
NASA Technical Reports Server (NTRS)
El-Raheb, M.
1980-01-01
The linear acoustic propagation in finite rigid three-dimensional waveguides is determined analytically using an eigenfunction expansion of the Helmholtz equation. The geometry considered consists of straight and circular bends of rectangular cross section with continuous interfaces (branches and sharp corners are excluded). The phenomena of resonance shift and relocation are explained for a bend-straight duct combination.
Three-Dimensional Extension of a Digital Library Service System
ERIC Educational Resources Information Center
Xiao, Long
2010-01-01
Purpose: The paper aims to provide an overall methodology and case study for the innovation and extension of a digital library, especially the service system. Design/methodology/approach: Based on the three-dimensional structure theory of the information service industry, this paper combines a comprehensive analysis with the practical experiences…
NASA Astrophysics Data System (ADS)
Hampel, Andrea; Hetzel, Ralf
2015-04-01
In recent years, more and more geological and space-geodetic data on the surface deformation associated with earthquakes on intra-continental normal and thrust faults have become available. Here we use three-dimensional finite-element models that account for gravity, far-field ("regional") extension/shortening and postseismic relaxation in a viscoelastic lower crust to quantify the surface deformation caused by an Mw ~7 earthquake on a dip-slip fault. The coseismic deformation is characterized by horizontal shortening in the footwall of the normal fault and extension in the hanging wall of the thrust fault - consistent with elastic dislocation models, geological field observations and GPS data from earthquakes in Italy and Taiwan. During the postseismic phase, domains of extensional and contractional strain exist next to each other near both fault types. The spatiotemporal evolution of these domains as well as the postseismic velocities and strain rates strongly depend on the viscosity of the lower crust. For viscosities of 1e18-1e20 Pa s, the signal from postseismic relaxation is detectible for 20-50 years after the earthquake. If GPS data containing a postseismic relaxation signal are used to derive regional rates, the stations may show rates that are too high or too low or even an apparently wrong tectonic regime. By quantifying the postseismic deformation through space and time, our models help to interpret GPS data and to identify the most suitable locations for GPS stations.
Three dimensional optic tissue culture and process
NASA Technical Reports Server (NTRS)
Spaulding, Glenn F. (Inventor); Prewett, Tacey L. (Inventor); Goodwin, Thomas J. (Inventor); Francis, Karen M. (Inventor); Cardwell, Delmar R. (Inventor); Oconnor, Kim (Inventor); Fitzgerald, Wendy S. (Inventor); Aten, Laurie A. (Inventor)
1994-01-01
A process for artificially producing three-dimensional optic tissue has been developed. The optic cells are cultured in a bioreactor at low shear conditions. The tissue forms normal, functional tissue organization and extracellular matrix.
Three Dimensional Optic Tissue Culture and Process
NASA Technical Reports Server (NTRS)
OConnor, Kim C. (Inventor); Spaulding, Glenn F. (Inventor); Goodwin, Thomas J. (Inventor); Aten, Laurie A. (Inventor); Francis, Karen M. (Inventor); Caldwell, Delmar R. (Inventor); Prewett, Tacey L. (Inventor); Fitzgerald, Wendy S. (Inventor)
1999-01-01
A process for artificially producing three-dimensional optic tissue has been developed. The optic cells are cultured in a bioireactor at low shear conditions. The tissue forms as normal, functional tissue grows with tissue organization and extracellular matrix formation.