Relationships Between Structural, Functional, and X-Ray Microcomputed Tomography Parameters of Pervious Concrete for Pavement Applications

2017 ◽  
Vol 2629 (1) ◽  
pp. 51-62 ◽  
Author(s):  
Anush Konayakanahalli Chandrappa ◽  
Krishna Prapoorna Biligiri
Keyword(s):  
Pore Structure ◽  
Surface Area ◽  
Three Dimensional ◽  
Pervious Concrete ◽  
X Ray ◽  
Computed Microtomography ◽  
Porosity And Permeability ◽  
One Step ◽  
Positive Correlations ◽  
The Individual

Several countries have begun using pervious concrete (PC) pavements to reduce the adverse effects of impermeable surfaces resulting from high-impact development. Pore parameters and their relationship to other PC properties are not yet fully understood; however, this information is essential for rational designs of PC pavements. This study investigated the strength, functional, and permeability properties of 18 PC mixtures and used X-ray computed microtomography methods to determine the three-dimensional pore parameters and their relationships, which were thought to affect PC properties. The major findings of this study included the observation that the failure mode in compression was of the shear brittle type, in which the failure plane was inclined at 45° to the ground, and impact abrasion resistance was higher for larger-sized aggregates and was chiefly attributable to the individual aggregate particles debonding. Permeability was more sensitive at low hydrostatic pressure than at higher pressures. The sphericity and compactness of pores had positive correlations with each other, unlike the relationship between surface area and sphericity. The tortuosity calculated for six of the PC mixtures was less than one; this finding was attributed mainly to the single-sized pore structure. Tortuosity increased with an increase in porosity and permeability and decreased with increasing surface area and pore radius. This research should move the current understanding of PC pore structure one step forward and, therefore, will be helpful in modeling PC in a rational manner.

Numerical study of the second harmonic generation in FELs

2021 ◽  
Vol 28 (3) ◽  
Author(s):  
A. M. Kalitenko
Keyword(s):  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Free Electron ◽  
Numerical Study ◽  
Second Harmonic ◽  
Three Dimensional ◽  
X Ray ◽  
Linac Coherent Light Source ◽  
The Individual ◽  
Analytical Expressions

A numerical study of the effect of betatron oscillations on the second harmonic generation in free-electron lasers (FELs) is presented. Analytical expressions for the effective coupling strength factors are derived that clearly distinguish all contributions in subharmonics and each polarization of the radiation. A three-dimensional time-dependent numerical FEL code that takes into account the main FEL effects and the individual contribution of each electron to the second harmonic generation is presented. Also, the X- and Y-polarizations of the second harmonic are analyzed. The second harmonic was detected in experiments at the Advanced Photon Source (APS) Low Energy Undulator Test Line (LEUTL) and Linac Coherent Light Source (LCLS) in the soft X-ray regime. The approach presented in the article can be useful for a comprehensive study and diagnostics of XFELs. In the paper, the LCLS and Pohang Accelerator Laboratory X-ray Free-Electron Laser (PAL-XFEL) experiments are modeled. The simulation results are in a good agreement with the experimental data.

scholarly journals One-Step Acidic Hydrothermal Preparation of Dendritic Rutile TiO2 Nanorods for Photocatalytic Performance

Nanomaterials ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 683 ◽  
Author(s):  
Cheng Gong ◽  
Jun Du ◽  
Xiuyun Li ◽  
Zhenjie Yu ◽  
Jiansong Ma ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Contact Angle ◽  
Hydrothermal Method ◽  
Photocatalytic Performance ◽  
Three Dimensional ◽  
Tio2 Nanorods ◽  
Foil Surface ◽  
Rutile Tio2 ◽  
X Ray ◽  
One Step

Three-dimensional and dendritic rutile TiO2 nanorods were successfully fabricated on a Ti foil surface using a one-step acidic hydrothermal method. The TiO2 nanorods were characterized using X-ray diffraction (XRD), energy dispersive X-ray spectrometry (EDX), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and optical contact angle testing. The results showed that the nanorods with diameters of 100–500 nm and lengths of 100 nm to 1 μm were obtained on the Ti foil surface. The length and density of the TiO2 nanorods were perfect at the conditions of HCl concentration 0.5 mol/L, temperature 220 °C, and reaction time 12 h. The TiO2 nanorods formed parallel to the consumption of Ti and grew along the (110) direction having a tetragonal rutile crystal. The morphology of the nanorods possessed a three-dimensional structure. The contact angle of the nanorods was only 13 ± 3.1°. Meanwhile, the photocatalytic activities of the TiO2 nanorods were carried out using ultraviolet fluorescence spectrophotometry for the methyl orange detection, and the degradation was found to be about 71.00% ± 2.43%. Thus, TiO2 nanorods can be developed by a one-step acidic hydrothermal method using Ti foil simultaneously as the substrate with a TiO2 source; the TiO2 nanorods exhibited photocatalytic performance while being environment-friendly.

scholarly journals Direct characterization of solute transport in unsaturated porous media using fast X-ray synchrotron microtomography

2020 ◽  
Vol 117 (38) ◽  
pp. 23443-23449 ◽  
Author(s):  
Sharul Hasan ◽  
Vahid Niasar ◽  
Nikolaos K. Karadimitriou ◽  
Jose R. A. Godinho ◽  
Nghia T. Vo ◽  
...  
Keyword(s):  
Solute Transport ◽  
High Speed ◽  
Three Dimensional ◽  
Concentration Field ◽  
Solute Concentration ◽  
Breakthrough Curves ◽  
Pore Scale ◽  
X Ray ◽  
Long Tails ◽  
Computed Microtomography

Solute transport in unsaturated porous materials is a complex process, which exhibits some distinct features differentiating it from transport under saturated conditions. These features emerge mostly due to the different transport time scales at different regions of the flow network, which can be classified into flowing and stagnant regions, predominantly controlled by advection and diffusion, respectively. Under unsaturated conditions, the solute breakthrough curves show early arrivals and very long tails, and this type of transport is usually referred to as non-Fickian. This study directly characterizes transport through an unsaturated porous medium in three spatial dimensions at the resolution of 3.25 μm and the time resolution of 6 s. Using advanced high-speed, high-spatial resolution, synchrotron-based X-ray computed microtomography (sCT) we obtained detailed information on solute transport through a glass bead packing at different saturations. A large experimental dataset (>50 TB) was produced, while imaging the evolution of the solute concentration with time at any given point within the field of view. We show that the fluids’ topology has a critical signature on the non-Fickian transport, which yet needs to be included in the Darcy-scale solute transport models. The three-dimensional (3D) results show that the fully mixing assumption at the pore scale is not valid, and even after injection of several pore volumes the concentration field at the pore scale is not uniform. Additionally, results demonstrate that dispersivity is changing with saturation, being twofold larger at the saturation of 0.52 compared to that at the fully saturated domain.

Dimensional Quantification of Embedded Voids or Objects in Three Dimensions Using X-Ray Tomography

2012 ◽  
Vol 18 (2) ◽  
pp. 390-398 ◽  
Author(s):  
Brian M. Patterson ◽  
Juan P. Escobedo-Diaz ◽  
Darcie Dennis-Koller ◽  
Ellen Cerreta
Keyword(s):  
Digital Imaging ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Post Processing ◽  
X Ray ◽  
Individual Object ◽  
Starting Point ◽  
X Ray Computed ◽  
The Individual ◽  
Processing Steps

AbstractScientific digital imaging in three dimensions such as when using X-ray computed tomography offers a variety of ways to obtain, filter, and quantify data that can produce vastly different results. These opportunities, performed during image acquisition or during the data processing, can include filtering, cropping, and setting thresholds. Quantifying features in these images can be greatly affected by how the above operations are performed. For example, during binarization, setting the threshold too low or too high can change the number of objects as well as their measured diameter. Here, two facets of three-dimensional quantification are explored. The first will focus on investigating the question of how many voxels are needed within an object to have accurate geometric statistics that are due to the properties of the object and not an artifact of too few voxels. These statistics include but are not limited to percent of total volume, volume of the individual object, Feret shape, and surface area. Using simple cylinders as a starting point, various techniques for smoothing, filtering, and other processing steps can be investigated to aid in determining if they are appropriate for a specific desired statistic for a real dataset. The second area of investigation is the influence of post-processing, particularly segmentation, on measuring the damage statistics in high purity Cu. The most important parts of the pathways of processing are highlighted.

Flowerlike submicrometer gold particles: Size- and surface roughness-controlled synthesis and electrochemical characterization

2010 ◽  
Vol 25 (9) ◽  
pp. 1755-1760 ◽  
Author(s):  
Changsheng Shan ◽  
Dongxue Han ◽  
Jiangfeng Song ◽  
Ari Ivaska ◽  
Li Niu
Keyword(s):  
Surface Area ◽  
Photoelectron Spectroscopy ◽  
Electrocatalytic Activity ◽  
Active Surface ◽  
Molar Ratio ◽  
Active Surface Area ◽  
Step Method ◽  
Gold Particles ◽  
X Ray ◽  
One Step

Flowerlike submicrometer gold particles were synthesized through a simple one-step method using p-diaminobenzene as a reductant in the presence of poly(sodium 4-styrenesulfonate) in aqueous solution. The particle size with diameters ranging from 267 to 725 nm could be tuned by varying the molar ratio of poly(sodium 4-styrenesulfonate) to HAuCl4, which also resulted in tunable roughness. The gold particles were confirmed by scanning electron microscopy, energy dispersive x-ray spectroscopy, x-ray diffraction, and x-ray photoelectron spectroscopy. Cyclic voltammetry showed that the specific surface area of the flowerlike particles was larger than that of sphere particles. The obtained flowerlike particles with higher surface area also exhibited higher electrocatalytic activity toward H2O2 and O2. The increase of electrocatalytic activity could be attributed to the increase of the active surface area.

scholarly journals Three-dimensional visualisation of the internal anatomy of the sparrowhawk (Accipiter nisus) forelimb using contrast-enhanced micro-computed tomography

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3039 ◽  
Author(s):  
Fernanda Bribiesca-Contreras ◽  
William I. Sellers
Keyword(s):  
Computed Tomography ◽  
3D Model ◽  
Three Dimensional ◽  
Biomechanical Analysis ◽  
X Ray ◽  
Accipiter Nisus ◽  
Contrast Enhanced ◽  
Muscle Geometry ◽  
The Individual ◽  
Non Destructive

BackgroundGross dissection is a widespread method for studying animal anatomy, despite being highly destructive and time-consuming. X-ray computed tomography (CT) has been shown to be a non-destructive alternative for studying anatomical structures. However, in the past it has been limited to only being able to visualise mineralised tissues. In recent years, morphologists have started to use traditional X-ray contrast agents to allow the visualisation of soft tissue elements in the CT context. The aim of this project is to assess the ability of contrast-enhanced micro-CT (μCT) to construct a three-dimensional (3D) model of the musculoskeletal system of the bird wing and to quantify muscle geometry and any systematic changes due to shrinkage. We expect that this reconstruction can be used as an anatomical guide to the sparrowhawk wing musculature and form the basis of further biomechanical analysis of flight.MethodsA 3% iodine-buffered formalin solution with a 25-day staining period was used to visualise the wing myology of the sparrowhawk (Accipiter nisus). μCT scans of the wing were taken over the staining period until full penetration of the forelimb musculature by iodine was reached. A 3D model was reconstructed by manually segmenting out the individual elements of the avian wing using 3D visualisation software.ResultsDifferent patterns of contrast were observed over the duration of the staining treatment with the best results occurring after 25 days of staining. Staining made it possible to visualise and identify different elements of the soft tissue of the wing. Finally, a 3D reconstruction of the musculoskeletal system of the sparrowhawk wing is presented and numerical data of muscle geometry is compared to values obtained by dissection.DiscussionContrast-enhanced μCT allows the visualisation and identification of the wing myology of birds, including the smaller muscles in the hand, and provides a non-destructive way for quantifying muscle volume with an accuracy of 96.2%. By combining contrast-enhanced μCT with 3D visualisation techniques, it is possible to study the individual muscles of the forelimb in their original position and 3D design, which can be the basis of further biomechanical analysis. Because the stain can be washed out post analysis, this technique provides a means of obtaining quantitative muscle data from museum specimens non-destructively.

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