Remarks on two and three dimensional consolidation analysis of sand-drained ground. Technical note

1992 ◽  
Vol 29 (4) ◽  
pp. 226
Keyword(s):  
Three Dimensional ◽  
Technical Note ◽  
Consolidation Analysis

An innovative prone positioning system for advanced deformity and frailty in complex spine surgery

2020 ◽  
Vol 32 (2) ◽  
pp. 229-234
Author(s):  
Benjamin Kolb ◽  
John Large ◽  
Stuart Watson ◽  
Glyn Smurthwaite
Keyword(s):  
Ankylosing Spondylitis ◽  
Three Dimensional ◽  
Technical Note ◽  
Positioning System ◽  
Prone Positioning ◽  
Economic Implications ◽  
Potential Safety ◽  
Chest Deformity ◽  
Positioning Device ◽  
Skin Quality

The authors present a technical note for a prone positioning system developed to facilitate cervical extension osteotomy for ankylosing spondylitis in the presence of severe deformity and frailty. Chin-on-chest deformity represents one of the most debilitating changes of ankylosing spondylitis. Where the chin-brow angle approaches or exceeds 90°, prone positioning becomes problematic due to the fixed position of the head. Furthermore, the challenge is compounded where physiological deconditioning leads to frailty, and the side effects of medical therapies decrease muscle mass and skin quality. Conventional prone positioning equipment is not able to cater to all patients. A versatile system was developed using a 3D reconstruction to enable a positioning simulation and verification tool. The tool was used to comprehensively plan the perioperative episode, including spatial orientation and associated equipment. Three-dimensional printing was used to manufacture a bespoke positioning device that precisely matched the contours of the patient, reducing contact pressure and risk of skin injury. The authors were able to safely facilitate surgery for a patient whose deformity and frailty may otherwise have precluded this possibility. The system has potential safety and economic implications that may be of significant utility to other institutions engaging in complex spinal surgery.

scholarly journals Probe-based three-dimensional confocal laser endomicroscopy of brain tumors: technical note

2018 ◽  
Vol Volume 10 ◽  
pp. 3109-3123 ◽  
Author(s):  
Evgenii Belykh ◽  
Arpan A Patel ◽  
Eric J Miller ◽  
Baran Bozkurt ◽  
Kaan Yağmurlu ◽  
...  
Keyword(s):  
Brain Tumors ◽  
Three Dimensional ◽  
Technical Note ◽  
Confocal Laser Endomicroscopy ◽  
Confocal Laser

A Sequel to Technical Note 13: The Curved Tetrahedronal and Triangular Elements TEC and TRIC for the Matrix Displacement Method

1969 ◽  
Vol 73 (697) ◽  
pp. 55-65 ◽  
Author(s):  
J. H. Argyris ◽  
D. W. Scharpf
Keyword(s):  
Computational Analysis ◽  
Three Dimensional ◽  
Technical Note ◽  
Radius Of Curvature ◽  
Two Dimensional ◽  
Displacement Method ◽  
Stress Concentrations ◽  
The Past ◽  
The Matrix ◽  
Triangular Elements

It is by now well established that the computational analysis of significant problems in structural and continuum mechanics by the matrix displacement method often requires elements of higher sophistication than used in the past. This refers, in particular, to regions of steep stress gradients, which are frequently associated with marked changes in geometry, involving rapid variations of the radius of curvature. The philosophy underlying the idealisation of such configurations into finite elements was discussed in broad terms in ref. 1. It was emphasised that the so successful, constant strain, two-dimensional TRIM 3 and three-dimensional TET 4 elements do not, in general, prove the best choice. For this reason elements with a linear variation of strain like TRIM 6 and TET 10 were originally evolved and followed up with the quadratic strain elements TRIM 15, TRIA 4 (two-dimensional) and TET 20, TEA 8 (three-dimensional) of ref. 2. However, all these elements are characterised by straight edges and necessitate a polygonisation or polyhedrisation in the idealisation process. This may not be critical in many problems, but is sometimes of doubtful validity in the immediate neighbourhood of a curved boundary, where stress concentrations are most pronounced. To overcome this difficulty with a significant (local) increase of elements does not always yield the most economical and technically satisfactory solution. Moreover, there arises another inevitable shortcoming when dealing with TRIM and TET elements with a linear or quadratic variation of strain. Indeed, while TRIM 3 and TET 4 elements permit a very elegant extension into the realm of large displacements, this is not possible for the higher order TRIM and TET elements. This is simply due to the fact that TRIM 3 and TET 4 elements, by virtue of their specification, always remain straight under any magnitude of strain, but this is not so for the triangular and tetrahedron elements of higher sophistication.

scholarly journals Technical Note: Three-dimensional transient groundwater flow due to localized recharge with an arbitrary transient rate in unconfined aquifers

2016 ◽  
Vol 20 (3) ◽  
pp. 1225-1239 ◽  
Author(s):  
Chia-Hao Chang ◽  
Ching-Sheng Huang ◽  
Hund-Der Yeh
Keyword(s):  
Groundwater Flow ◽  
Integral Transform ◽  
Three Dimensional ◽  
Observation Point ◽  
Technical Note ◽  
Specific Yield ◽  
Vertical Flow ◽  
Dimensional Flow ◽  
Special Cases ◽  
Present Solution

Abstract. Most previous solutions for groundwater flow induced by localized recharge assumed either aquifer incompressibility or two-dimensional flow in the absence of the vertical flow. This paper develops a new three-dimensional flow model for hydraulic head variation due to localized recharge in a rectangular unconfined aquifer with four boundaries under the Robin condition. A governing equation describing spatiotemporal head distributions is employed. The first-order free-surface equation with a source term defining a constant recharge rate over a rectangular area is used to depict water table movement. The solution to the model for the head is developed with the methods of Laplace transform and double-integral transform. Based on Duhamel's theorem, the present solution is applicable to flow problems accounting for arbitrary time-dependent recharge rates. The solution to depth-average head can then be obtained by integrating the head solution to elevation and dividing the result by the aquifer thickness. The use of a rectangular aquifer domain has two merits. One is that the integration for estimating the depth-average head can be analytically achieved. The other is that existing solutions based on aquifers of infinite extent can be considered as special cases of the present solution before the time when the aquifer boundary had an effect on head predictions. With the help of the present solution, the assumption of neglecting the vertical flow effect on the temporal head distribution at an observation point outside a recharge region can be assessed by a dimensionless parameter related to the aquifer horizontal and vertical hydraulic conductivities, initial aquifer thickness, and the shortest distance between the observation point and the edge of the recharge region. The validity of assuming aquifer incompressibility is dominated by the ratio of the aquifer specific yield to its storage coefficient. In addition, a sensitivity analysis is performed to investigate the head response to the change in each of the aquifer parameters.

Three-dimensional Visualization of the Pyramidal Tract in a Neuronavigation System during Brain Tumor Surgery: First Experiences and Technical Note

Neurosurgery ◽  
2001 ◽  
Vol 49 (1) ◽  
pp. 86-93 ◽  
Author(s):  
Volker A. Coenen ◽  
Timo Krings ◽  
Lothar Mayfrank ◽  
Richard S. Polin ◽  
Marcus H.T. Reinges ◽  
...  
Keyword(s):  
Brain Tumor ◽  
Pyramidal Tract ◽  
Three Dimensional ◽  
Technical Note ◽  
Tumor Surgery ◽  
Brain Tumor Surgery ◽  
Neuronavigation System ◽  
Surgery First

scholarly journals Technical Note: A new SIze REsolved Aerosol Model (SIREAM)

2007 ◽  
Vol 7 (6) ◽  
pp. 1537-1547 ◽  
Author(s):  
E. Debry ◽  
K. Fahey ◽  
K. Sartelet ◽  
B. Sportisse ◽  
M. Tombette
Keyword(s):  
Size Distribution ◽  
Transport Model ◽  
Three Dimensional ◽  
Technical Note ◽  
Aerosol Size Distribution ◽  
Short Paper ◽  
Chemistry Transport Model ◽  
Dynamical Mass ◽  
Aerosol Model ◽  
Transfer Method

Abstract. We briefly present in this short paper a new SIze REsolved Aerosol Model (SIREAM) which simulates the evolution of atmospheric aerosol by solving the General Dynamic Equation (GDE). SIREAM segregates the aerosol size distribution into sections and solves the GDE by splitting coagulation and condensation/evaporation-nucleation. A quasi-stationary sectional approach is used to describe the size distribution change due to condensation/evaporation, and a hybrid equilibrium/dynamical mass-transfer method has been developed to lower the computational burden. SIREAM uses the same physical parameterizations as those used in the Modal Aerosol Model, MAM Sartelet et al. (2006). It is hosted in the modeling system Polyphemus Mallet et al., 2007, but can be linked to any other three-dimensional Chemistry-Transport Model.

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