scholarly journals Creación de implantes 3D en procesos de conservación y restauración de vidrio arqueológico

2017 ◽  
Vol 8 (16) ◽  
pp. 103 ◽  
Author(s):  
Carmen Díaz-Marín ◽  
Elvira Aura-Castro

This article describes the restoration of a glass bowl from the 16th-17thcentury by creating its three-dimensional (3D)model. The final purpose is to work with this model in order to avoid damaging situations that are associated with the manipulation of fragile objects. The gap areas, those corresponding to the missing fragments not found in the excavation, were carried out by constructing digital implants. A restricted area of the 3D model has been duplicated in order to accommodate it to confined intervals of the gap. The final implants were printed with acrylonitrile butadiene styrene (ABS) filament. These implants replace the lost areas and give stability back to the item by recovering the original morphology. The result can be compared with the outcome obtained by a traditional process, but differs due to the fact that requires minimum manipulation of the item, so it can contribute to preserve and safeguard the restored object. This is a non-invasive method which is offered as an alternative treatment, where the archaeological object is replaced by its virtual model in the steps of the process after 3D data acquisition. Significant differences have not been found in the 3D printing results obtained with the two types of filaments tested (white and clear).

2020 ◽  
Vol 59 (47) ◽  
pp. 20686-20692
Author(s):  
Aarón Cabrera ◽  
Ismael Pellejero ◽  
Tamara Oroz-Mateo ◽  
Cristina Salazar ◽  
Alberto Navajas ◽  
...  

Author(s):  
M. A. Al-Rawi ◽  
A. M. Al-Jumaily ◽  
A. Lowe

Non-invasive diagnosis of cardiovascular diseases is a valuable tool to reduce patient’s risk and discomfort. The main aim of this work is to investigate the possibilities of using computational fluid dynamics as a tool to investigate the biomechanical characteristics of the aorta under different medical conditions. These conditions include an aorta with healthy conditions, atherosclerosis and aneurysm. A three dimensional pulsatile flow model for an elastic aorta is developed and constructed in ANSYS® CFX 12. Abnormalities are simulated as diameter changes at the root of the ascending aorta. The computational model shows the reflection of these diseases on the blood flow and the artery wall at other locations downstream along the aorta. This 3D model has several advantages over previously published 1D and 2D models by giving more realistic results as compared with clinical trials.


2014 ◽  
Vol 644-650 ◽  
pp. 4121-4124
Author(s):  
Qiang Chen ◽  
Li Mei Xu

This paper mainly studies modeling and recognition of 3D English words’ images. With the development of secondary modeling, segmentation and recognition theories and the application of evolution computation in 3D modeling and recognition, this paper analyzes the issues of parameter fitting in the 3D model, multi-object scene segmentation and parts recognition aiming at the 3D data features in the English words. The 3D model is used as the primitives part to model and segment the scenes and the group parallel evolution and the relationship matching theories are introduced into the 3D modeling and recognition to deeply identify the rare English words’ images. The paper searches for a practical and efficient three-dimensional modeling and identification scheme.


2021 ◽  
Author(s):  
Nengfeng Ma ◽  
Xufeng Hu ◽  
Zhoushan Tao ◽  
Min Yang

Abstract Purpose To use three-dimensional (3D) virtual models to study how the parameters and insertion rates of the infra-acetabular corridor (IAC) change under different fluoroscopic angles. Methods The pelvis computed tomography data of 187 patients are imported into Mimics software in DICOM format to generate a 3D model. The anterior pelvis plane is used as the reference plane to measure the diameter of the optimum IAC when the pelvis model is tilted forward by 5°, 15°, 25°, 35° and 45°. The diameter of at least 3.5 mm is defined as the cutoff for placing a 3.5 mm screw, the rate of infra-acetabular screw (IAS) insertion is calculated, and the mean length of the IAC and the mean tilt of the corridor axis in relation to the sagittal midline plane (SMP) are measured. Results The similar diameters of the IAC can be found under fluoroscopy at 5°–35°, with the largest diameter of 4.08 ± 1.84 mm and the highest screw insertion rate of 60.42% at 15° and 25°, whereas the diameter and insertion rate are lowest at 45°. The corridor length increases with increasing fluoroscopic angle, and the angle of the corridor axis to the SMP decreases gradually. Conclusions The traditional 45° pelvic inlet radiograph is not suitable as the fluoroscopic angle for IAS insertion. The parameters of the IAC vary according to a certain rule under different fluoroscopic angles, so a surgeon can select the appropriate fluoroscopic angle in accordance with the type of fracture and the fracture line angle.


Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3737
Author(s):  
Yousef Lafi A. Alshammari ◽  
Feiyang He ◽  
Muhammad A. Khan

Three-dimensional (3D) printing is one of the significant industrial manufacturing methods in the modern era. Many materials are used for 3D printing; however, as the most used material in fused deposition modelling (FDM) technology, acrylonitrile butadiene styrene (ABS) offers good mechanical properties. It is perfect for making structures for industrial applications in complex environments. Three-dimensional printing parameters, including building orientation, layers thickness, and nozzle size, critically affect the crack growth in FDM structures under complex loads. Therefore, this paper used the dynamic bending vibration test to investigate their influence on fatigue crack growth (FCG) rate under dynamic loads and the Paris power law constant C and m. The paper proposed an analytical solution to determine the stress intensity factor (SIF) at the crack tip based on the measurement of structural dynamic response. The experimental results show that the lower ambient temperature, as well as increased nozzle size and layer thickness, provide a lower FCG rate. The printing orientation, which is the same as loading, also slows the crack growth. The linear regression between these parameters and Paris Law’s coefficient also proves the same conclusion.


2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Nengfeng Ma ◽  
Xufeng Hu ◽  
Zhoushan Tao ◽  
Min Yang

Abstract Purpose To use three-dimensional (3D) virtual models to study how the parameters and insertion rates of the infra-acetabular corridor (IAC) change under different fluoroscopic angles. Methods The pelvis computed tomography data of 187 patients are imported into Mimics software in DICOM format to generate a 3D model. The anterior pelvis plane is used as the reference plane to measure the diameter of the optimum IAC when the pelvis model is tilted forward by 5°, 15°, 25°, 35° and 45°. The diameter of at least 3.5 mm is defined as the cutoff for placing a 3.5 mm screw, the rate of infra-acetabular screw (IAS) insertion is calculated, and the mean length of the IAC and the mean tilt of the corridor axis in relation to the sagittal midline plane (SMP) are measured. Results The similar diameters of the IAC can be found under fluoroscopy at 5°–35°, with the largest diameter of 4.08 ± 1.84 mm and the highest screw insertion rate of 60.42% at 15° and 25°, whereas the diameter and insertion rate are lowest at 45°. The corridor length increases with increasing fluoroscopic angle, and the angle of the corridor axis to the SMP decreases gradually. Conclusion The conventional fluoroscopic angle of the pelvic inlet is not suitable for the IAS insertion. The parameters of the IAC vary according to a certain rule under different fluoroscopic angles, so a surgeon can select the appropriate fluoroscopic angle in accordance with the type of fracture and the fracture line angle.


Author(s):  
Hussain Z. Tameem ◽  
Bhavin V. Mehta

This investigation uses a multi disciplinary approach to standardize a non-invasive method for measuring human vocal tract morphology. A series of Magnetic Resonance Imaging (MRI) scans are performed on the subject’s vocal tract and a detailed three-dimensional model is created through image processing and computer modeling. This information is compared with the vocal tract measurements obtained with Eccovision Acoustic Pharyngometer, in order to establish the accuracy of the instrument. The model is then used to develop other specific models through parametric modeling. This method is useful in creating solid models with limited geometrical information and helps researchers study the human vocal tract changes due to aging and degenerative diseases.


Author(s):  
S.U. Maksyukov ◽  
D.V. Yogina ◽  
D.S. Maksyukov

The aim of the study was to evaluate the effectiveness of a non-invasive method of treating caries at the stage of a white chalky spot with the Infiltration Concept (Icon) technology. Materials and methods: the clinical and laboratory study included 5 teeth with caries in the white spot stage, removed according to orthodontic indications. The study included scanning in an X-ray computer microtomograph of selected samples of teeth with caries in the white spot stage before and after treatment of the caries area according to Icon technology. For each sample, 1601 X-ray projections were obtained, which were then reconstructed using the XRM Reconstructor software. The comparison of the mineralization density of the samples was carried out by calibrating the obtained images, reconstructing three-dimensional models of tooth samples and constructing maps of the mineralization fee. Results and conclusions. Data on the mineralization density before and after treatment according to Icon technology were obtained in the following areas of the studied teeth: caries in the white spot stage; dentin bordering on caries (the area touches the dentinoemal border as close as possible to the caries area); the area of healthy enamel on the opposite side of the tooth; dentin bordering on healthy enamel (near the dentinoemal border and as close as possible to the healthy enamel area). A comparison of the results obtained does not allow us to conclude about the effectiveness of treatment according to the Icon technology. Moreover, the mineralization density of the studied areas significantly decreased after the treatment.


2020 ◽  
Vol 16 (1) ◽  
Author(s):  
Chi-Pin Hsu ◽  
Chen-Si Lin ◽  
Chun-Hao Fan ◽  
Nai-Yuan Chiang ◽  
Ching-Wen Tsai ◽  
...  

Abstract Background Three-dimensional (3D) printing techniques have been used to produce anatomical models and surgical guiding instruments in orthopaedic surgery. The geometric accuracy of the 3D printed replica may affect surgical planning. This study assessed the geometric accuracy of an acrylonitrile butadiene styrene (ABS) canine tibia model printed using fused deposition modelling (FDM) and evaluated its morphological change after hydrogen peroxide (H2O2) gas plasma sterilisation. The tibias of six canine cadavers underwent computed tomography for 3D reconstruction. Tibia models were fabricated from ABS on a 3D printer through FDM. Reverse-engineering technology was used to compare morphological errors (root mean square; RMS) between the 3D-FDM models and virtual models segmented from original tibia images (3D-CT) and between the models sterilised with H2O2 gas plasma (3D-GAS) and 3D-FDM models on tibia surface and in cross-sections at: 5, 15, 25, 50, 75, 85, and 95% of the tibia length. Results The RMS mean ± standard deviation and average positive and negative deviation values for all specimens in EFDM-CT (3D-FDM vs. 3D-CT) were significantly higher than those in EGAS-FDM (3D-GAS vs. 3D-FDM; P < 0.0001). Mean RMS values for EFDM-CT at 5% bone length (proximal tibia) were significantly higher than those at the other six cross-sections (P < 0.0001). Mean RMS differences for EGAS-FDM at all seven cross-sections were nonsignificant. Conclusions The tibia models fabricated on an FDM printer had high geometric accuracy with a low RMS value. The surface deviation in EFDM-CT indicated that larger errors occurred during manufacturing than during sterilisation. Therefore, the model may be used for surgical rehearsal and further clinically relevant applications in bone surgery. Graphical abstract


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