scholarly journals Mechanical and Microscopic Characteristics of Polyurethane-Based Pervious Pavement Composites

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4365
Author(s):  
Hongdong Cho ◽  
Hongsu Bae ◽  
Chanho Park ◽  
Hyeong Min Park ◽  
Seo-Eun Oh ◽  
...  
Keyword(s):  
Morphological Characteristics ◽  
Element Model ◽  
Micro Ct ◽  
Micro Computed Tomography ◽  
X Ray ◽  
Pavement Materials ◽  
Pervious Pavement ◽  
Brittle Behavior ◽  
Internal Structures ◽  
Ct Analysis

Conventional pervious pavement materials (PPM) that consist of cement and aggregate materials are known for poor durability due to their brittle behavior. Thus, to enhance the durability, we fabricated polymeric PPMs from durable and abundant polyurethane (PU) and undertook mechanical and microscopic characterizations. PU-based PPM samples with varying aggregate sizes were produced and examined to test their compressive strength and water permeability. Furthermore, X-ray micro-computed tomography (micro-CT) was implemented to analyze the samples’ pore and tortuosity characteristics. Through the micro-CT analysis, the morphological characteristics of PPM’s internal structures were identified and quantitively analyzed the correlations between the pore size distribution, connectivity, and tortuosity within the samples. Finally, the microstructures derived from micro-CT were generated as a finite element model and also numerically determined the stress distribution generated inside.

scholarly journals Mechanical and Microscopic Characteristics of Polyurethane-Based Pervious Pavement Composites

2021 ◽  
Author(s):  
Hongdong Cho ◽  
Hongsu Bae ◽  
Changho Park ◽  
Hyeong Min Park ◽  
Seo-Eun Oh ◽  
...  
Keyword(s):  
Morphological Characteristics ◽  
Element Model ◽  
Micro Ct ◽  
Micro Computed Tomography ◽  
X Ray ◽  
Pavement Materials ◽  
Pervious Pavement ◽  
Brittle Behavior ◽  
Internal Structures ◽  
Ct Analysis

Conventional pervious pavement materials (PPM) consist of cement and aggregate materials and are known for poor durability due to their brittle behavior. Herein, we fabricated polymeric PPMs from durable and abundant polyurethane (PU) to enhance the durability of the material and undertook mechanical and microscopic characterizations. PU-based PPM samples with varying aggregate sizes were produced and the compressive strength and water permeability of each were examined. The pore and tortuosity characteristics of the specimens were analyzed using X-ray micro-computed tomography (micro-CT). Through the micro-CT analysis, the morphological characteristics of the internal structures of PPM were identified and the correlations between the pore size distribution, connectivity, and tortuosity within the specimen were quantitatively analyzed. The microstructures derived from micro-CT were generated as a finite element model and the stress distribution generated inside was numerically determined.

scholarly journals A Micro-Computed Tomography Comparison of the Porosity in Additively Fabricated CuCr1 Alloy Parts Using Virgin and Surface-Modified Powders

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1995
Author(s):  
Mirko Sinico ◽  
Suraj Dinkar Jadhav ◽  
Ann Witvrouw ◽  
Kim Vanmeensel ◽  
Wim Dewulf
Keyword(s):  
High Energy ◽  
High Energy Density ◽  
Micro Ct ◽  
Micro Computed Tomography ◽  
Powder Bed ◽  
Metallurgical Defects ◽  
Ct Analysis ◽  
Ct Data ◽  
Surface Modified ◽  
Fusion Pores

Recently, the use of novel CuCr1 surface-modified powder for reliable laser powder-bed fusion (LPBF) manufacturing has been proposed, enabling a broader LPBF processing window and longer powder storage life. Nevertheless, virgin CuCr1 powder is also LPBF processable, on the condition that a high-energy density is employed. In this work, we compare two dense specimens produced from virgin and surface-modified CuCr1 powder. Furthermore, a third sample fabricated from surface-modified powder is characterized to understand an abnormal porosity content initially detected through Archimedes testing. Utilizing high-resolution micro-CT scans, the nature of the defects present in the different samples is revealed. Pores are analyzed in terms of size, morphology and spatial distribution. The micro-CT data reveal that the virgin CuCr1 dense specimen displays keyhole pores plus pit cavities spanning multiple layer thicknesses. On the other hand, the sample fabricated with the surface-modified CuCr1 powder mainly contains small and spherical equi-distributed metallurgical defects. Finally, the CT analysis of the third specimen reveals the presence of a W contamination, favoring lack-of-fusion pores between subsequent LPBF layers. The LPBF melting mode (keyhole or conductive), the properties of the material, and the potential presence of contaminants are connected to the different porosity types and discussed.

Quantitative micro-computed tomography analysis and rheological investigation of Nitrile rubber/Rockwool composites

2021 ◽  
pp. 002199832110338
Author(s):  
Elisson BD da Rocha ◽  
Ana Maria F de Sousa ◽  
Ana Lúcia N da Silva ◽  
Cristina RG Furtado ◽  
Marcos V Colaço ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Elastic Modulus ◽  
Aspect Ratio ◽  
Volume Fraction ◽  
Nitrile Rubber ◽  
Micro Ct ◽  
Micro Computed Tomography ◽  
Rubber Composites ◽  
Ratio Data ◽  
Ct Analysis

This study reports the reinforcement degree investigation of two types of rockwool fibers (F1 and F2), in nitrile rubber composites. The micro-computed tomography (micro-CT) 3D images showed that both fibers were well-dispersed in the NBR matrix, without a preferential orientation. The micro-CT analysis also allowed quantifying volume fraction, inter-fiber distance, and aspect ratio. Those morphometric parameters were used for supporting the composites rheological behavior assessment. Changes in the elastic modulus and phase angle followed the same trend of the inter-fiber distance values, regardless the type of fiber. Both volume fraction and aspect ratio data from the micro-CT analysis were used to predict theoretical values of elastic modulus using the Guth-Gold and modified Guth-Gold equations, and the results obtained were compared to the rheological experimental data. This analysis was helpful to better understand the rockwool fibers reinforcement degree differences in the production of the nitrile rubber composites.

scholarly journals Impact of DBBM Fragments on the Porosity of the Calvarial Bone: A Pilot Study on Mice

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4748
Author(s):  
Ulrike Kuchler ◽  
Patrick Heimel ◽  
Alexandra Stähli ◽  
Franz Josef Strauss ◽  
Bernadette Luza ◽  
...  
Keyword(s):  
Morphological Changes ◽  
Histological Evaluation ◽  
Random Allocation ◽  
Bovine Bone ◽  
Distribution Analysis ◽  
Micro Ct ◽  
Micro Computed Tomography ◽  
Calvarial Bone ◽  
Ct Analysis ◽  
Bovine Bone Mineral

Deproteinized bovine bone mineral (DBBM) is brittle and can break into fragments. Here, we examined whether DBBM fragments have an impact on mice calvarial bone during bone augmentation. DBBM was either randomly crushed (DBBM fragments) or left undisturbed (DBBM granules). Then, DBBM fragments or original DBBM granules were placed onto calvarial bone in 20 BALB/c mice. Following random allocation, ten mice received DBBM fragments and ten mice received original DBBM granules. After fourteen days of healing, micro computed tomography (micro-CT) and histological analysis of the augmented sites were performed. The primary outcome was the porosity of the calvarial bone. The micro-CT analysis revealed that DBBM fragments failed to significantly change the porosity of the calvarial bone as compared with original DBBM granules, despite the slightly higher bone resorption in the DBBM fragment group, 10.3% (CI 6.3–11.6) versus 6.1% (CI 4.1–7.8, p = 0.355), respectively. The cortical bone volume was not altered by DBBM fragments as compared with original DBBM granules, i.e., 79.0% (CI 78.9–81.2) versus 81.5% (CI 80.1–83.3, p = 0.357), respectively. The DBBM fragment group revealed similar bone thickness values as compared with the DBBM granules group, i.e., 0.26 mm (CI 0.23–0.29) versus 0.25 mm (CI 0.22–0.27, p = 0.641), respectively. The histological evaluation supported the micro-CT observations, displaying minor signs of porosity and resorption. The particle-size distribution analysis confirmed a shift towards smaller particle sizes in the DBBM fragment group. These findings suggest that DBBM fragments behave similarly to original DBBM granules in terms of bone morphological changes at augmented sites.

scholarly journals Endogenous Production of n-3 Polyunsaturated Fatty Acids Promotes Fracture Healing in Mice

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Yuhui Chen ◽  
He Cao ◽  
Dawei Sun ◽  
Changxin Lin ◽  
Liang Wang ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Fracture Healing ◽  
Histological Analysis ◽  
Callus Formation ◽  
Healing Process ◽  
Proximal Femoral Fracture ◽  
Fracture Repair ◽  
Micro Ct ◽  
Micro Computed Tomography ◽  
X Ray

Bone fracture is a global healthcare issue for high rates of delayed healing and nonunions. Although n-3 polyunsaturated fatty acid (PUFA) is considered as a beneficial factor for bone metabolism, only few studies till date focused on the effects of n-3 PUFAs on fracture healing. In this study, we investigated the effect of endogenous n-3 PUFAs on fracture healing by measuring femur fracture repair in bothfat-1transgenic mice and WT mice. Proximal femoral fracture model was established infat-1transgenic mice and WT mice, respectively, and then the fracture was analyzed by using X-ray, micro-computed tomography (micro-CT), and histological assessment at 7, 14, 21, 28, and 35 days after fixation. The results showed that compared with WT mice,fat-1mice exhibited acceleration in fracture healing through radiographic and histological analysis (18–21 days versus 21–28 days postfracture). Meanwhile, X-ray and micro-CT analysis that showed better remodeling callus formation were in thefat-1group compared to WT group. Furthermore, histological analysis revealed that endogenous n-3 PUFAs promoted local endochondral ossification and accelerated the remodeling of calcified calluses after fracture. In conclusion, the present study indicated that endogenously produced n-3 PUFAs promote fracture healing process and accelerate bone remodeling in mice, and supplementation of n-3 PUFAs was positively associated with fracture healing.

Hypophosphatasia: Evaluation of Size and Mineral Density of Exfoliated Teeth

2016 ◽  
Vol 40 (6) ◽  
pp. 496-502 ◽  
Author(s):  
S Hayashi-Sakai ◽  
N Numa-Kinjoh ◽  
M Sakamoto ◽  
J Sakai ◽  
J Matsuyama ◽  
...  
Keyword(s):  
Density Distribution ◽  
Primary Teeth ◽  
Micro Ct ◽  
Micro Computed Tomography ◽  
Mineral Density ◽  
Normal Range ◽  
Mean Values ◽  
Present Patient ◽  
Ct Analysis ◽  
The Mean

Objective: Most cases of hypophosphatasia (HPP) exhibit early loss of primary teeth. Results of micro-computed tomography (micro-CT) analysis of teeth with HPP have not yet been reported. The purpose of the present study was to describe the size and mineral density distribution and mapping of exfoliated teeth with HPP using micro CT. Study design: Seven exfoliated teeth were obtained from a patient with HPP. Exfoliated teeth sizes were measured on micro CT images and mineral densities of the mandibular primary central incisors were determined. Results: Partial dentures were fabricated for the patient to replace the eight primary teeth which had exfoliated. Most primary teeth sizes were within the normal range. The mean values of enamel and dentin mineral densities in teeth with HPP were 1.35 and 0.88 g/cm3, respectively, in the mandibular primary central incisors. Conclusion: Mineral density distribution and mapping revealed that the values in teeth with HPP were lower than the homonymous teeth controls in all regions from the crown to apex. Furthermore, it was demonstrated that the differences between HPP and controls were larger on the crown side and the differences tended to converge on the apex side. These results suggested that the present patient showed mild hypomineralization in the primary dentition.

Enhanced X-ray absorption for micro-CT analysis of low density polymers

2016 ◽  
Vol 27 (9) ◽  
pp. 805-823 ◽  
Author(s):  
Livia Elena Crica ◽  
Jonas Wengenroth ◽  
Hanna Tiainen ◽  
Mariana Ionita ◽  
Håvard Jostein Haugen
Keyword(s):  
Low Density ◽  
Micro Ct ◽  
X Ray ◽  
Ct Analysis ◽  
X Ray Absorption

scholarly journals Investigating the Evolution of Fractures in Clay–based Ceramics During Repeated Freeze-Thawing Cycles Using Micro X-Ray Computed Tomography and Image Analysis

2020 ◽  
Author(s):  
Carlo Porfido ◽  
Roberto Rizzo ◽  
David Healy ◽  
Matteo Spagnuolo ◽  
Roberto Terzano ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Methodological Approach ◽  
Fracture Initiation ◽  
Micro Ct ◽  
Micro Computed Tomography ◽  
X Ray ◽  
Freeze Thaw ◽  
Fracture Length ◽  
Grain Distribution ◽  
Fracture Damage

<div><div><div><p>This work presents a study on the fracturing behaviour of a quartz tempered clay-based ceramic subjected to damage in freeze-thaw cycles. X-ray micro-computed tomography (micro-CT) provided high-resolution imaging of the ceramic before and during the freeze-thaw treatment, allowing to analyse a fully water-saturated sample using a special thermal stage designed to keep the sample frozen during analyses. Micro-CT 3D renderings showed the internal features of the specimen (i.e., quartz grain distribution), the increment of fracture count and size, and the detachment of ceramic and/or temper fragments from the edges of the sample over the cycles. Selected 2D micrographs, before and after freeze-thawing treatment, were analysed using the MATLAB toolbox FracPaQ. This software provided detailed data on fracture length, intensity, density, orientation and connectivity, and enabled to interpret the process of fracture initiation and propagation inside the material. These results showed that the temper plays a crucial role in ceramic fracturing behaviour under freeze- thawing conditions, as damage propagation is influenced by quartz grain distribution and orientation within the material. The study described in this work, not only offers new insights into the fracture dynamics of freeze-thawed clay-based ceramics, but also presents a new methodological approach to quantitatively measure fracture damage in porous materials.</p></div></div></div>

scholarly journals Generalized Pulp Stones of Primary Dentition in a Patient with Molar-Incisor Malformation : A Case Report

2020 ◽  
Vol 47 (3) ◽  
pp. 337-343
Author(s):  
Dongyun Lee ◽  
Jisun Shin
Keyword(s):  
Case Report ◽  
Primary Dentition ◽  
Micro Ct ◽  
Micro Computed Tomography ◽  
X Ray ◽  
Second Molar ◽  
New Type ◽  
Mandibular First Molar ◽  
Pulp Stones ◽  
Scanning Electron

Molar-incisor malformation (MIM) is a new type of root anomaly reported recently. The characteristics of MIM are dysplastic root formations, constriction of pulp chambers and presence of calcified matrices at the level of cementoenamel junction in permanent first molars and primary second molars. In some cases, permanent maxillary incisors are also affected.The permanent first molars of the patient in this case report were affected with MIM. Generalized pulp stones were observed in overall primary dentition. Micro-computed tomography (micro-CT) imaging and scanning electron microscope-energy dispersive X-ray spectrometer analysis were performed on the extracted mandibular first molar and maxillary primary second molar of the patient. Micro-CT images revealed the discontinuity of enamel directly connected to an accessory canal of the root.

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