Modeling of Self-healing Process in Bituminous Materials: Experimental and Numerical Models

2021 ◽  
pp. 187-213
Author(s):  
Guoqiang Sun ◽  
Daquan Sun ◽  
Mingjun Hu ◽  
Alvaro Guarin ◽  
Jose Norambuena-Contreras
Keyword(s):  
Numerical Models ◽  
Healing Process ◽  
Self Healing ◽  
Bituminous Materials

scholarly journals Injectable Self-Healing Adhesive pH-Responsive Hydrogels Accelerate Gastric Hemostasis and Wound Healing

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Jiahui He ◽  
Zixi Zhang ◽  
Yutong Yang ◽  
Fenggang Ren ◽  
Jipeng Li ◽  
...  
Keyword(s):  
Wound Healing ◽  
Endoscopic Treatment ◽  
Healing Process ◽  
Gelation Time ◽  
Type I ◽  
Self Healing ◽  
Ph Responsive ◽  
Gastric Hemorrhage ◽  
Wound Model ◽  
Arterial Bleeding

AbstractEndoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) are well-established therapeutics for gastrointestinal neoplasias, but complications after EMR/ESD, including bleeding and perforation, result in additional treatment morbidity and even threaten the lives of patients. Thus, designing biomaterials to treat gastric bleeding and wound healing after endoscopic treatment is highly desired and remains a challenge. Herein, a series of injectable pH-responsive self-healing adhesive hydrogels based on acryloyl-6-aminocaproic acid (AA) and AA-g-N-hydroxysuccinimide (AA-NHS) were developed, and their great potential as endoscopic sprayable bioadhesive materials to efficiently stop hemorrhage and promote the wound healing process was further demonstrated in a swine gastric hemorrhage/wound model. The hydrogels showed a suitable gelation time, an autonomous and efficient self-healing capacity, hemostatic properties, and good biocompatibility. With the introduction of AA-NHS as a micro-cross-linker, the hydrogels exhibited enhanced adhesive strength. A swine gastric hemorrhage in vivo model demonstrated that the hydrogels showed good hemostatic performance by stopping acute arterial bleeding and preventing delayed bleeding. A gastric wound model indicated that the hydrogels showed excellent treatment effects with significantly enhanced wound healing with type I collagen deposition, α-SMA expression, and blood vessel formation. These injectable self-healing adhesive hydrogels exhibited great potential to treat gastric wounds after endoscopic treatment.

scholarly journals Application of GGBFS and Bentonite to Auto-Healing Cracks of Cement Paste

2018 ◽  
Vol 1 (1) ◽  
pp. 38 ◽  
Author(s):  
J J Ekaputri ◽  
M S Anam ◽  
Y Luan ◽  
C Fujiyama ◽  
N Chijiwa ◽  
...  
Keyword(s):  
Cement Paste ◽  
Surface Crack ◽  
Crack Width ◽  
Healing Process ◽  
Crack Depth ◽  
The Self ◽  
External Loading ◽  
Self Healing ◽  
Carbonation Reaction ◽  
Granulated Blast Furnace Slag

Cracks are caused by many factors. Shrinkage and external loading are the most common reason. It becomes a problem when the ingression of aggressive and harmful substance penetrates to the concrete gap. This problem reduces the durability of the structures. It is well known that self – healing of cracks significantly improves the durability of the concrete structure. This paper presents self-healing cracks of cement paste containing bentonite associated with ground granulated blast furnace slag. The self-healing properties were evaluated with four parameters: crack width on the surface, crack depth, tensile strength recovery, and flexural recovery. In combination with microscopic observation, a healing process over time is also performed. The results show that bentonite improves the healing properties, in terms of surface crack width and crack depth. On the other hand, GGBFS could also improve the healing process, in terms of crack depth, direst tensile recovery, and flexural stiffness recovery. Carbonation reaction is believed as the main mechanism, which contributes the self-healing process as well as the continuous hydration progress.

scholarly journals The importance of oxygen release in diabetic foot ulcer wounds

2019 ◽  
Vol 1 (1) ◽  
pp. 002-011
Keyword(s):  
Diabetic Foot ◽  
Therapeutic Process ◽  
Healing Process ◽  
Foot Ulcer ◽  
Essential Element ◽  
Diabetic Foot Ulcer ◽  
Wound Dressings ◽  
Self Healing ◽  
Healthy Human ◽  
Affected Tissue

Oxygen is the essential element required for proper physiological function of cells, tissues and organs within healthy human body. Thanks to its intricate structure, the skin provides a multiprotective barrier against traumatic and non-traumatic injuries, but also a complex and successful self-healing process of the affected tissue. In the particular case of chronic skin wounds, such as diabetic foot ulcer wounds, there is an immediate demand to develop alternative procedures that prevent infection, speed up healing and eliminate any disrupting factor that may interfere with the therapeutic process. Given the importance of oxygen during wound healing cascade, impressive attention was oriented towards the fabrication of oxygen-releasing wound dressings.

Inhibitor-Containing Composite Coatings on Mg Alloys: Corrosion Mechanism and Self-Healing Protection

2015 ◽  
Vol 245 ◽  
pp. 89-96 ◽  
Author(s):  
Andrey S. Gnedenkov ◽  
Sergey L. Sinebryukhov ◽  
Dmitry V. Mashtalyar ◽  
Sergey V. Gnedenkov
Keyword(s):  
Plasma Electrolytic Oxidation ◽  
Composite Coatings ◽  
Healing Process ◽  
Corrosion Mechanism ◽  
Self Healing ◽  
Protective Properties ◽  
Oxidation Method ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic ◽  
Electrode Technique

The way of self-healing coating formation at the surface of magnesium alloys by means of plasma electrolytic oxidation method (PEO) with subsequent filling of the obtained layer with inhibitor has been suggested. The electrochemical properties of such coatings have been described in details. The obtained experimental results indicate that the protective properties of the samples with inhibitor-containing coating were increased (IC = 8.6×10–8 A/cm2) in comparison with the samples without coating (5.3×10–5 A/cm2) and the base coating obtained by plasma electrolytic oxidation method (PEO) (3.4×10–7 A/cm2). The local scanning electrochemical methods of surface investigation, notably Scanning Vibrating Electrode Technique (SVET) and Scanning Ion-Selective Electrode Technique (SIET) were used for determining the kinetics and mechanism of the self-healing process. The treatment by the solution containing 8-hydroxyquinoline, which inhibits the corrosion process, enables one to increase the protective properties of the composite coating in 30 times in the corrosion-active environment in comparison with the base PEO-coating and avert the intensive destruction of the material.

scholarly journals Swap-Driven Self-Adhesion and Healing of Vitrimers

Coatings ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 114 ◽  
Author(s):  
Simone Ciarella ◽  
Wouter Ellenbroek
Keyword(s):  
Molecular Dynamics ◽  
Relaxation Time ◽  
Stress Relaxation ◽  
Healing Process ◽  
Star Polymers ◽  
Coarse Grained ◽  
Self Healing ◽  
Central Question ◽  
Trade Off ◽  
Dynamics Simulations

Vitrimers are covalent network materials, comparable in structure to classical thermosets. Unlike normal thermosets, they possess a chemical bond swap mechanism that makes their structure dynamic and suitable for activated welding and even autonomous self-healing. The central question in designing such materials is the trade-off between autonomy and material stability: the swap mechanism facilitates the healing, but it also facilitates creep, which makes the perfectly stable self-healing solid a hard goal to reach. Here, we address this question for the case of self-healing vitrimers made from star polymers. Using coarse-grained molecular dynamics simulations, we studied the adhesion of two vitrimer samples and found that they bond together on timescales that are much shorter than the stress relaxation time. We showed that the swap mechanism allows the star polymers to diffuse through the material through coordinated swap events, but the healing process is much faster and does not depend on this mobility.

scholarly journals Lamb-Wave-Based Method in the Evaluation of Self-Healing Efficiency

2020 ◽  
Vol 10 (7) ◽  
pp. 2585
Author(s):  
Maciej Radzieński ◽  
Paweł Kudela ◽  
Wiesław Ostachowicz ◽  
Patryk Bolimowski ◽  
Rafał Kozera ◽  
...  
Keyword(s):  
Lamb Wave ◽  
Composite Laminates ◽  
Impact Damage ◽  
Healing Process ◽  
Nondestructive Method ◽  
Laser Vibrometer ◽  
Self Healing ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Healing Efficiency

The aim of this research is a feasibility study of self-healing process monitoring in composite laminates. A novel nondestructive method based on the full wavefield of Lamb wave processing is proposed. Experimental verification is presented for glass-fiber-reinforced polymer plate with embedded self-healing function in the form of a dry microcapsule powder. After impacting the specimen to create barely visible impact damage, a series of laser vibrometer full wavefield measurements were carried out and processed to assess self-healing efficiency.

scholarly journals Self-Healing Potential of Geopolymer Concrete

Proceedings ◽  
2019 ◽  
Vol 34 (1) ◽  
pp. 6
Author(s):  
Rajczakowska ◽  
Habermehl-Cwirzen ◽  
Hedlund ◽  
Cwirzen
Keyword(s):  
Building Materials ◽  
Crack Opening ◽  
Healing Process ◽  
Activation Parameters ◽  
Optical Microscope ◽  
Bending Test ◽  
Geopolymer Concrete ◽  
Self Healing ◽  
Lime Water ◽  
Activated Slag

Waste management is emerging as one of the most troublesome and critical problems of the upcoming decades. Therefore, the utilization of industrial by-products as building materials components has been widely studied in recent years. Geopolymer concrete, with binder entirely substituted by slag or fly ash, is one of the materials, which combines positive environmental impact with satisfying mechanical parameters. Although various properties of geopolymers have been examined, the autogeneous self-healing potential of this alternative binder has not been thoroughly verified yet. This paper aims to validate whether geopolymer concrete made of alkali activated slag is capable of self-repair. Four different mortar mixes with two types of slag and varying activation parameters were investigated. The polyvinyl alcohol (PVA) fibers were added in order to control the crack width. The 1.2 × 1.2 × 6 cm beams were pre-cracked with the use of three point bending test at 7 days after casting to achieve crack opening of approximately 300 µm. The effects of various exposure conditions on the healing process were examined, i.e., lime water, different sodium silicate solutions and water. The self-healing efficiency as well as the evolution of the crack recovery was assessed by the observation of the crack surface with the use of digital optical microscope. The healed area of the crack was calculated and compared for all the specimens by applying the image processing techniques. The morphology of the healing products as well as their chemical composition were examined with the use of Scanning Electron Microscope with Energy Dispersive Spectroscopy.

scholarly journals Method for Assessment of Changes in the Width of Cracks in Cement Composites with Use of Computer Image Processing and Analysis

2017 ◽  
Vol 39 (2) ◽  
pp. 73-80 ◽  
Author(s):  
Kamil Tomczak ◽  
Jacek Jakubowski ◽  
Przemysław Fiołek
Keyword(s):  
Image Processing ◽  
Crack Width ◽  
Healing Process ◽  
Cement Composites ◽  
Self Healing ◽  
Initial Image ◽  
Scale Invariant ◽  
Line Segments ◽  
Changes Over Time ◽  
Over Time

Abstract Crack width measurement is an important element of research on the progress of self-healing cement composites. Due to the nature of this research, the method of measuring the width of cracks and their changes over time must meet specific requirements. The article presents a novel method of measuring crack width based on images from a scanner with an optical resolution of 6400 dpi, subject to initial image processing in the ImageJ development environment and further processing and analysis of results. After registering a series of images of the cracks at different times using SIFT conversion (Scale-Invariant Feature Transform), a dense network of line segments is created in all images, intersecting the cracks perpendicular to the local axes. Along these line segments, brightness profiles are extracted, which are the basis for determination of crack width. The distribution and rotation of the line of intersection in a regular layout, automation of transformations, management of images and profiles of brightness, and data analysis to determine the width of cracks and their changes over time are made automatically by own code in the ImageJ and VBA environment. The article describes the method, tests on its properties, sources of measurement uncertainty. It also presents an example of application of the method in research on autogenous self-healing of concrete, specifically the ability to reduce a sample crack width and its full closure within 28 days of the self-healing process.

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