scholarly journals Automated Quantification of Pneumothorax in CT

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Synho Do ◽  
Kristen Salvaggio ◽  
Supriya Gupta ◽  
Mannudeep Kalra ◽  
Nabeel U. Ali ◽  
...  
Keyword(s):  
Processing Time ◽  
Three Dimensional ◽  
Average Error ◽  
Two Dimensional ◽  
Algorithm Performance ◽  
Automated Method ◽  
Automated Quantification ◽  
Overall Performance ◽  
Processing Techniques ◽  
Aided Diagnosis

An automated, computer-aided diagnosis (CAD) algorithm for the quantification of pneumothoraces from Multidetector Computed Tomography (MDCT) images has been developed. Algorithm performance was evaluated through comparison to manual segmentation by expert radiologists. A combination of two-dimensional and three-dimensional processing techniques was incorporated to reduce required processing time by two-thirds (as compared to similar techniques). Volumetric measurements on relative pneumothorax size were obtained and the overall performance of the automated method shows an average error of just below 1%.

Numerical and Experimental Investigation of Return Channel Vane Aerodynamics With Two-Dimensional and Three-Dimensional Vanes

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
A. Hildebrandt ◽  
F. Schilling
Keyword(s):  
Experimental Investigation ◽  
Flow Field ◽  
Static Pressure ◽  
Three Dimensional ◽  
Pressure Rise ◽  
Field Performance ◽  
Two Dimensional ◽  
Flow Angle ◽  
Overall Performance ◽  
Return Channel

The present paper deals with the numerical and experimental investigation of the effect of return channel (RCH) dimensions of a centrifugal compressor stage on the aerodynamic performance. Three different return channel stages were investigated, two stages comprising three-dimensional (3D) return channel blades and one stage comprising two-dimensional (2D) RCH vanes. The analysis was performed regarding both the investigation of overall performance (stage efficiency, RCH total pressure loss coefficient) and detailed flow-field performance. For detailed experimental flow-field investigation at the stage exit, six circumferentially traversed three-hole probes were positioned downstream the return channel exit in order to get two-dimensional flow-field information. Additionally, static pressure wall measurements were taken at the hub and shroud pressure and suction side (SS) of the 2D and 3D return channel blades. The return channel system overall performance was calculated by measurements of the circumferentially averaged 1D flow field downstream the diffuser exit and downstream the stage exit. Dependent on the type of return channel blade, the numerical and experimental results show a significant effect on the flow field overall and detail performance. In general, satisfactory agreement between computational fluid dynamics (CFD)-prediction and test-rig measurements was achieved regarding overall and flow-field performance. In comparison with the measurements, the CFD-calculated stage performance (efficiency and pressure rise coefficient) of all the 3D-RCH stages was slightly overpredicted. Very good agreement between CFD and measurement results was found for the static pressure distribution on the RCH wall surfaces while small CFD-deviations occur in the measured flow angle at the stage exit, dependent on the turbulence model selected.

scholarly journals Performance Characteristics of Two- and Three-Dimensional Impellers in Centrifugal Compressors

1986 ◽  
Author(s):  
H. Harada
Keyword(s):  
Centrifugal Compressor ◽  
Closed Loop ◽  
Three Dimensional ◽  
Performance Characteristics ◽  
Working Fluid ◽  
Angle Distribution ◽  
Two Dimensional ◽  
Blade Angle ◽  
Operating Range ◽  
Overall Performance

The overall performance of two- and three-dimensional impellers of a centrifugal compressor were tested and compared. A closed loop test stand with Freon gas as working fluid was employed for the experiments. The inlet and outlet velocity distribtions of all impellers were measured using three hole cobra probes. As a result, it has been revealed that three-dimensional impellers are superior to two-dimensional one in terms of efficiency, head coefficient and operating range. Further, it has also been clarified that the impeller slip factor is affected by blade angle distribution.

Numerical Modelling of Three Dimensional Honeycomb Labyrinth Seals Employing a Simplified Approach

2006 ◽  
Author(s):  
Dermot Collins ◽  
Joao Amaral Teixeira ◽  
Pete Crudgington ◽  
Paul C. Ivey
Keyword(s):  
Three Dimensional ◽  
Two Dimensional ◽  
Labyrinth Seals ◽  
Cfd Simulations ◽  
Simplified Approach ◽  
Pressure Profiles ◽  
Single Tooth ◽  
Average Variation ◽  
Flow Through ◽  
Overall Performance

This paper numerically analyses the flow through abradable honeycomb labyrinth seals using CFD. Three-dimensional CFD simulations using a single tooth have been compared to representative two-dimensional simulations. Two sizes of honeycomb (1.60mm and 3.20mm) have been analysed at pressure ratios from 1.20 up to 1.60. The seal geometry was kept constant throughout with a running clearance of 1.00mm. The honeycomb has been oriented in two planes with respect to the labyrinth teeth. The two-dimensional planes show equivalence both in terms of overall performance and inter-cavity pressure profiles. Comparisons of Cd typically agree within 2.5%, having an average variation of 1.3%. Total pressure profiles at the middle of the upstream and downstream cavity have been compared. These reveal typical average RMS variations of less than 3% between 3-D and 2-D profiles. It has also been shown that the honeycomb surface causes velocity effects in 3-D that propagate into the seal cavity. The technique used has achieved significant reductions in modelling times.

3D Photonic Crystals Fabricated by Micromanipulation Technique

2002 ◽  
Vol 722 ◽  
Author(s):  
Kanna Aoki ◽  
Hideki T. Miyazaki ◽  
Hideki Hirayama ◽  
Kyoji Inoshita ◽  
Toshihiko Baba ◽  
...  
Keyword(s):  
Photonic Crystals ◽  
Photonic Band Gap ◽  
Three Dimensional ◽  
Wavelength Region ◽  
Two Dimensional ◽  
Positioning Error ◽  
Proper Position ◽  
Number Of Layers ◽  
Processing Techniques ◽  
Photonic Band

AbstractThree-dimensional (3D) photonic crystals with one to four layers of woodpile structures have been fabricated by stacking two-dimensional (2D) photonic plates by micromanipulation. First, air-bridge photonic plates were fabricated as unit structures using conventional IC processing techniques. Then, the 2D photonic plates were stacked using a micromanipulation system. To obtain lattices with precise periodicity, microspheres were inserted into the round openings which were prepared in the frame of the plates. Since neighboring plates have pore openings at the same position, plates were laminated at the proper position automatically. Consequently, positioning error was kept within 50 nm. Optical characteristics of the crystals were evaluated by their reflectance and transmittance at wavenumber between 700 and 7000 cm-1. The formed photonic crystals were expected to have a photonic band gap at around 3030 cm-1. As the number of layers was increased, the reflectance at around 3030 cm-1 increased to 60 %, and the transmittance at the same wavelength region decreased to 30 %.

TWO‐DIMENSIONAL AND THREE‐DIMENSIONAL MIGRATION OF MODEL‐EXPERIMENT REFLECTION PROFILES

Geophysics ◽  
1974 ◽  
Vol 39 (3) ◽  
pp. 265-277 ◽  
Author(s):  
William S. French
Keyword(s):  
Model Experiment ◽  
Three Dimensional ◽  
Structural Models ◽  
Computer Processing ◽  
Three Dimensions ◽  
Two Dimensional ◽  
Migration Process ◽  
Subsurface Structures ◽  
Reflection Data ◽  
Processing Techniques

A reflection profile represents an unfocused picture of the subsurface. In areas of rapid structural change, this unfocused picture may not reveal directly the true geometry of subsurface structures. Computer processing techniques, collectively called migration, have been used by many companies to focus 2-D reflection data. A description of the migration process can be given which allows immediate generalization to three‐dimensions with arbitrary source and receiver positions. Reflection profiles digitally recorded in the laboratory over known acoustically semitransparent structural models establish the effectiveness of migration. Processed reflection data over 3-D models demonstrate that 3-D migration eliminates many of the lateral correlation ambiguities caused by “sideswipes” and “blind structures.” Structure maps developed from the results of 3-D migration of reflection data give a true and precise picture of 3-D models. When the same data are processed using 2-D migration, the mapped structures are distorted. In structurally complex areas it is desirable to collect 3-D reflection data. Single profiles cannot, and conventional grids may not, reveal adequate cross‐dip information.

scholarly journals Digital Applications in Endodontics

2021 ◽  
Vol 38 (SI-2) ◽  
pp. 168-174
Author(s):  
Cangül KESKİN ◽  
Ali KELEŞ
Keyword(s):  
Imaging Techniques ◽  
Three Dimensional ◽  
Digital Technologies ◽  
Two Dimensional ◽  
Digital Dentistry ◽  
Advantages And Disadvantages ◽  
Training And Research ◽  
Student Training ◽  
Computer Controlled ◽  
Aided Diagnosis

The aim of this review was to provide an overview of the applications of digital dentistry technologies in endodontics, such as digital two-dimensional (2-D) and three-dimensional (3-D) imaging techniques, computer aided diagnosis (CAD) and improvement of artificial intelligence (AI) models, computer-controlled access cavity designs and 3-D printing applications. Advantages and disadvantages of these newly introduced technologies were discussed briefly with their indications. Apart from therapeutical or rehabilitative procedures, the use of digital technologies adapted for student training and research simulations were also presented.

scholarly journals Regularization of DT-MRI Using 3D Median Filtering Methods

2014 ◽  
Vol 2014 ◽  
pp. 1-11
Author(s):  
Soondong Kwon ◽  
Dongyoun Kim ◽  
Bongsoo Han ◽  
Kiwoon Kwon
Keyword(s):  
Diffusion Tensor ◽  
Three Dimensional ◽  
Synthetic Data ◽  
Regularization Methods ◽  
Median Filtering ◽  
Two Dimensional ◽  
Median Filters ◽  
Highly Sensitive ◽  
The Central Nervous System ◽  
Processing Techniques

DT-MRI (diffusion tensor magnetic resonance imaging) tractography is a method to determine the architecture of axonal fibers in the central nervous system by computing the direction of the principal eigenvectors obtained from tensor matrix, which is different from the conventional isotropic MRI. Tractography based on DT-MRI is known to need many computations and is highly sensitive to noise. Hence, adequate regularization methods, such as image processing techniques, are in demand. Among many regularization methods we are interested in the median filtering method. In this paper, we extended two-dimensional median filters already developed to three-dimensional median filters. We compared four median filtering methods which are two-dimensional simple median method (SM2D), two-dimensional successive Fermat method (SF2D), three-dimensional simple median method (SM3D), and three-dimensional successive Fermat method (SF3D). Three kinds of synthetic data with different altitude angles from axial slices and one kind of human data from MR scanner are considered for numerical implementation by the four filtering methods.

High Resolution Microscopy of Multi-Layered Biological Crystals

1982 ◽  
Vol 40 ◽  
pp. 80-83
Author(s):  
H.A. Cohen ◽  
T.W. Jeng ◽  
W. Chiu
Keyword(s):  
High Resolution ◽  
Low Dose ◽  
Three Dimensional ◽  
Data Interpretation ◽  
Two Dimensional ◽  
Biological Objects ◽  
Density Maps ◽  
Density Map ◽  
Complex Crystal ◽  
High Resolution Microscopy

This tutorial will discuss the methodology of low dose electron diffraction and imaging of crystalline biological objects, the problems of data interpretation for two-dimensional projected density maps of glucose embedded protein crystals, the factors to be considered in combining tilt data from three-dimensional crystals, and finally, the prospects of achieving a high resolution three-dimensional density map of a biological crystal. This methodology will be illustrated using two proteins under investigation in our laboratory, the T4 DNA helix destabilizing protein gp32*I and the crotoxin complex crystal.

Instrumentation For Quantitative Microscopy

1977 ◽  
Vol 35 ◽  
pp. 206-209
Author(s):  
B. Ralph ◽  
A.R. Jones
Keyword(s):  
Volume Fraction ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Automatic Data ◽  
Phase Volume Fraction ◽  
Statistical Confidence ◽  
Resultant Data ◽  
Automatic Data Collection ◽  
Third Dimension ◽  
Evolution Of Microstructure

In all fields of microscopy there is an increasing interest in the quantification of microstructure. This interest may stem from a desire to establish quality control parameters or may have a more fundamental requirement involving the derivation of parameters which partially or completely define the three dimensional nature of the microstructure. This latter categorey of study may arise from an interest in the evolution of microstructure or from a desire to generate detailed property/microstructure relationships. In the more fundamental studies some convolution of two-dimensional data into the third dimension (stereological analysis) will be necessary.In some cases the two-dimensional data may be acquired relatively easily without recourse to automatic data collection and further, it may prove possible to perform the data reduction and analysis relatively easily. In such cases the only recourse to machines may well be in establishing the statistical confidence of the resultant data. Such relatively straightforward studies tend to result from acquiring data on the whole assemblage of features making up the microstructure. In this field data mode, when parameters such as phase volume fraction, mean size etc. are sought, the main case for resorting to automation is in order to perform repetitive analyses since each analysis is relatively easily performed.

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