Accuracy and Reproducibility of CFD Predicted Wall Shear Stress Using 3D Ultrasound Images

2003 ◽  
Vol 125 (2) ◽  
pp. 218-222 ◽  
Author(s):  
A. D. Augst ◽  
D. C. Barratt ◽  
A. D. Hughes ◽  
F. P. Glor ◽  
S. A. McG. Thom ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Cfd Simulation ◽  
Imaging Techniques ◽  
Flow Simulation ◽  
3D Ultrasound ◽  
Quantitative Agreement ◽  
Ultrasound Images ◽  
Simulation Techniques ◽  
Average Maximum ◽  
Aided Design

Computational fluid dynamics (CFD) flow simulation techniques have the potential to enhance our understanding of how haemodynamic factors are involved in atherosclerosis. Recently, 3D ultrasound has emerged as an alternative to other 3D imaging techniques, such as magnetic resonance angiography (MRA). The method can be used to generate realistic vascular geometry suitable for CFD simulations. In order to assess accuracy and reproducibility of the procedure from image acquisition to reconstruction to CFD simulation, a human carotid artery bifurcation phantom was scanned three times using 3D ultrasound. The geometry was reconstructed and flow simulations were carried out on the three sets as well as on a model generated using computer aided design (CAD) from the geometric information given by the manufacturer. It was found that the three reconstructed sets showed good reproducibility as well as satisfactory quantitative agreement with the CAD model. Analyzing two selected locations probably representing the ‘worst cases,’ accuracy comparing ultrasound and CAD reconstructed models was estimated to be between 7.2% and 7.7% of the maximum instantaneous WSS and reproducibility comparing the three scans to be between 8.2% and 10.7% of their average maximum.

scholarly journals Biomechanical Effects of Different Auxiliary-Aligner Designs for the Extrusion of an Upper Central Incisor: A Finite Element Analysis

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
R. Savignano ◽  
R. Valentino ◽  
A. V. Razionale ◽  
A. Michelotti ◽  
S. Barone ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Computer Aided Design ◽  
Imaging Techniques ◽  
Central Incisor ◽  
Element Analysis ◽  
Maxillary Central Incisor ◽  
Force Moment ◽  
Aided Design ◽  
Effective Design

Aim. To evaluate the biomechanical effects of four different auxiliary-aligner combinations for the extrusion of a maxillary central incisor and to define the most effective design through finite element analysis (FEA). Materials and Methods. A full maxillary arch (14 teeth) was modelled by combining two different imaging techniques: cone beam computed tomography and surface-structured light scan. The appliance and auxiliary element geometries were created by exploiting computer-aided design (CAD) procedures. The reconstructed digital models were imported within the finite element solver (Ansys® 17). For the extrusion movement, the authors compared the aligner without an attachment with three auxiliary-aligner designs: a rectangular palatal attachment, a rectangular buccal attachment, and an ellipsoid buccal attachment. The resulting force-moment (MF) system delivered by the aligner to the target tooth and the tooth displacement were calculated for each scenario. Results. The maximum tooth displacement along the z-axis (0.07 mm) was obtained with the rectangular palatal attachment, while the minimum (0.02 mm) was obtained without any attachments. With the ellipsoid attachment, the highest undesired moments Mx and My were found. The rectangular palatal attachment showed the highest Fz (2.0 N) with the lowest undesired forces (Fx = 0.4 N; Fy = −0.2 N). Conclusions. FEA demonstrated that the rectangular palatal attachment can improve the effectiveness of the appliance for the extrusion of an upper central incisor.

Modeling the Nonlinear Motion of the Rat Central Airways

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
G. Ibrahim ◽  
A. Rona ◽  
S. V. Hainsworth
Keyword(s):  
Computer Aided Design ◽  
Imaging Techniques ◽  
Three Dimensional ◽  
Ct Images ◽  
Breath Hold ◽  
Breathing Cycle ◽  
Sprague Dawley ◽  
Nonlinear Motion ◽  
Aided Design ◽  
Central Airway

Advances in volumetric medical imaging techniques allowed the subject-specific modeling of the bronchial flow through the first few generations of the central airways using computational fluid dynamics (CFD). However, a reliable CFD prediction of the bronchial flow requires modeling of the inhomogeneous deformation of the central airways during breathing. This paper addresses this issue by introducing two models of the central airways motion. The first model utilizes a node-to-node mapping between the discretized geometries of the central airways generated from a number of successive computed tomography (CT) images acquired dynamically (without breath hold) over the breathing cycle of two Sprague-Dawley rats. The second model uses a node-to-node mapping between only two discretized airway geometries generated from the CT images acquired at end-exhale and at end-inhale along with the ventilator measurement of the lung volume change. The advantage of this second model is that it uses just one pair of CT images, which more readily complies with the radiation dosage restrictions for humans. Three-dimensional computer aided design geometries of the central airways generated from the dynamic-CT images were used as benchmarks to validate the output from the two models at sampled time-points over the breathing cycle. The central airway geometries deformed by the first model showed good agreement to the benchmark geometries within a tolerance of 4%. The central airway geometry deformed by the second model better approximated the benchmark geometries than previous approaches that used a linear or harmonic motion model.

Computer-Aided Design of a TSOP II LOC Package Using Taguchi’s Parameter Design Method to Optimize Mold-Flow Balance

2003 ◽  
Vol 125 (2) ◽  
pp. 268-275 ◽  
Author(s):  
Hung-Lung Lee ◽  
Shyang-Jye Chang ◽  
Sheng-Jye Hwang ◽  
Francis Su ◽  
S. K. Chen
Keyword(s):  
Computer Aided Design ◽  
Design Method ◽  
Flow Simulation ◽  
Design Parameters ◽  
Packaging Design ◽  
Control Factors ◽  
Flow Balance ◽  
Robust Design Method ◽  
Aided Design ◽  
Mold Flow

This paper presents a methodology for TSOP II LOC packaging design. The design objectives are: 1) to optimize mold-flow balance, which in turn minimizes air traps, and 2) to minimize manufacturing variability, which implies optimal quality. A mold-flow simulation tool called C-MOLD is used to evaluate various design configurations. Taguchi’s robust design method is used for manufacturing variability considerations. The simulated results are verified with experimental flow patterns produced by means of “short shots.” In the nomenclature of the Taguchi method, mold-flow balance was chosen as quality characteristics and select a set of design parameters called control factors. The objectives are to find the levels of the control factors, which optimize the flow balance, and, at the same time, minimize the sensitivity of the variations of the control factors.

scholarly journals Art and science in the design of physically large and complex systems

2011 ◽  
Vol 468 (2139) ◽  
pp. 891-912 ◽  
Author(s):  
D. J. Andrews
Keyword(s):  
Computer Aided Design ◽  
Crucial Aspect ◽  
Art And Science ◽  
Physical Size ◽  
Simulation Techniques ◽  
Computer Based ◽  
High Level ◽  
Aided Design ◽  
Practice Of Science

Designs of physically large and complex (PL&C) systems, nowadays, are achieved through the use of evermore capable digital computer-based techniques. Thus, the process of such designs might be characterized as the practice of science rather than that of an art. The article commences with a consideration of art and science in design. It then addresses the particular nature of the design of such systems and how this is not just an issue of complexity, but also a consequence of large physical size. How computer-aided design is applied early in the designing of such systems, the crucial aspect of the choice of style by the initial designer and the advent of computer-based simulation techniques, applied early in design, are all considered pertinent to the role of art and science in design. A series of high-level fundamental issues are discussed in the belief that they are changing the nature of the design of PL&C systems and ought to be considered by practitioners of such designs. In this way, the power of computer-based techniques, both numerical and graphical, can then enhance the scope of design innovation, given designers' increasing dependency on digitally based practice.

scholarly journals A quantization assisted U-Net study with ICA and deep features fusion for breast cancer identification using ultrasonic data

2021 ◽  
Vol 7 ◽  
pp. e805
Author(s):  
Talha Meraj ◽  
Wael Alosaimi ◽  
Bader Alouffi ◽  
Hafiz Tayyab Rauf ◽  
Swarn Avinash Kumar ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Computer Aided Design ◽  
Cost Effective ◽  
Breast Lesions ◽  
Ultrasound Images ◽  
Cad System ◽  
Open Access Database ◽  
Aided Design ◽  
Ultrasonic Images ◽  
Lasso Method

Breast cancer is one of the leading causes of death in women worldwide—the rapid increase in breast cancer has brought about more accessible diagnosis resources. The ultrasonic breast cancer modality for diagnosis is relatively cost-effective and valuable. Lesion isolation in ultrasonic images is a challenging task due to its robustness and intensity similarity. Accurate detection of breast lesions using ultrasonic breast cancer images can reduce death rates. In this research, a quantization-assisted U-Net approach for segmentation of breast lesions is proposed. It contains two step for segmentation: (1) U-Net and (2) quantization. The quantization assists to U-Net-based segmentation in order to isolate exact lesion areas from sonography images. The Independent Component Analysis (ICA) method then uses the isolated lesions to extract features and are then fused with deep automatic features. Public ultrasonic-modality-based datasets such as the Breast Ultrasound Images Dataset (BUSI) and the Open Access Database of Raw Ultrasonic Signals (OASBUD) are used for evaluation comparison. The OASBUD data extracted the same features. However, classification was done after feature regularization using the lasso method. The obtained results allow us to propose a computer-aided design (CAD) system for breast cancer identification using ultrasonic modalities.

scholarly journals Evaluation of Working Temperature in Wind Turbine Bearings by Simulation of Lubricant Level

2021 ◽  
Vol 16 (1) ◽  
pp. 99-104
Author(s):  
Yorley Arbella Feliciano ◽  
Carlos A. Trinchet Varela ◽  
Javier A. Vargas Guativas ◽  
Leandro L. Lorente-Leyva ◽  
Diego H. Peluffo-Ordóñez
Keyword(s):  
Computer Aided Design ◽  
Wind Farm ◽  
Thermal State ◽  
Flow Simulation ◽  
Engineering Software ◽  
Theoretical Predictions ◽  
Computational Fluid Dynamics Cfd ◽  
Historical Database ◽  
Aided Design ◽  
And Behavior

After studies related to the technical state and behavior of the temperatures manifested by the bearings of the generators that make up the Goldwind wind turbines models S50-750, installed in the Gibara II Wind Farm (PE). It was identified and validated as a tool that enables early diagnosis of anomalous bearing behaviors, SolidWorks (SW) computer-aided design and engineering software (CAD-CAE) and the Flow Simulation add-on. Since it allows studies based on the computational fluid dynamics (CFD), of the temperatures that are manifested in the lubricant during the different working regimes of the generator. The studies carried out evaluated the environmental conditions of exploitation in Cuba. It works on obtaining and predicting the values of the thermal state using the principles and methods for the calculation of heat transfer, the forecast statistics apply. The research supports its theories and postulates in a sample of 6 installed equipment, from China, for it had a historical database that collects temperature measurements in different working conditions which allowed to establish correlation between theoretical predictions and real behaviors.

scholarly journals Parallel Mesh Adaptive Techniques for Complex Flow Simulation: Geometry Conservation

2012 ◽  
Vol 2012 ◽  
pp. 1-13
Author(s):  
Angelo Casagrande ◽  
Pénélope Leyland ◽  
Luca Formaggia
Keyword(s):  
Computer Aided Design ◽  
Unstructured Grids ◽  
Flow Simulation ◽  
Mesh Adaptation ◽  
Computational Time ◽  
Complex Flow ◽  
Efficient Tool ◽  
Refinement Process ◽  
Solution Accuracy ◽  
Aided Design

Dynamic mesh adaptation on unstructured grids, by localised refinement and derefinement, is a very efficient tool for enhancing solution accuracy and optimising computational time. One of the major drawbacks, however, resides in the projection of the new nodes created, during the refinement process, onto the boundary surfaces. This can be addressed by the introduction of a library capable of handling geometric properties given by a CAD (computer-aided design) description. This is of particular interest also to enhance the adaptation module when the mesh is being smoothed, and hence moved, to then reproject it onto the surface of the exact geometry.

scholarly journals The Role of HDlive Technology in Obstetrics and Gynecology, Present and Future

2014 ◽  
Vol 8 (3) ◽  
pp. 234-238
Author(s):  
Mihaela Grigore ◽  
Camelia Cojocaru ◽  
Tudor Lazar
Keyword(s):  
Imaging Techniques ◽  
Three Dimensional ◽  
3D Ultrasound ◽  
Early Embryo ◽  
Obstetrics And Gynecology ◽  
Ultrasound Images ◽  
High Definition ◽  
Maternal Bonding ◽  
4D Ultrasound

ABSTRACT Imaging techniques have continually evolved during the last few decades to improve diagnosis in obstetrics and gynecology. Developed more than 15 years ago, three-dimensional (3D) ultrasound has been widely used in clinical practice during the last decade, and its use continues to grow as researchers explore innovative new applications. High definition live (HDlive) ultrasound (US) is a novel ultrasound technology that improves both 3D and four-dimensional (4D) ultrasound images. This technology can mainly be used to study normal and pathologic embryonic and fetal development. HDlive could be important to perinatal research and could provide a better understanding of the development of the early embryo and fetus. Because of the natural pictures of the fetus that it provides, HDlive could be beneficial for increasing the fetal-maternal bonding, an important factor for healthy behavior during the pregnancy. In gynecology, HDlive could be useful in providing a better image of the adnexal pathology or coronal plane of the uterus. Although its advantages need to be further explored, in our opinion, HDlive is an innovative technique and a useful tool with applications both in obstetrics and gynecology. How to cite this article Grigore M, Cojocaru C, Lazar T. The Role of HDlive Technology in Obstetrics and Gynecology, Present and Future. Donald School J Ultrasound Obstet Gynecol 2014;8(3):234-238.

Sign in / Sign up

Export Citation Format

Share Document