Journal articles: 'HEALING AGENT'

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Shields, Yasmina, Vanessa Cappellesso, Tim Van Mullem, Nele De Belie, and Kim Van Tittelboom. "A comparison of potential healing agents for vascular-based self-healing concrete." MATEC Web of Conferences 378 (2023): 02026. http://dx.doi.org/10.1051/matecconf/202337802026.

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Vascular self-healing concrete is an innovative technology that can potentially improve the durability and longevity of concrete structures. However, limited research is available concerning this type of self-healing compared to intrinsic or capsule-based healing. As the rheology and curing properties of a healing agent can dictate the optimal design configuration of a vascular network, a series of testing procedures for evaluating healing agents is further explored. In this study, the suitability of various commercially available healing agents is considered using a vascular network system in mechanical loading and water absorption test set-ups. In this particular configuration, high sealing efficiencies were obtained for most of the healing agents used, and the polyurethanes and epoxy resin that were studied showed high load regain values. This work provides a testing methodology to select a healing agent in terms of its mechanical load regain, sealing efficiency, rheology, and curing properties, and can be used to determine a suitable healing agent for vascular healing applications.

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Ebrahimnezhad-Khaljiri, Hossein, Reza Eslami-Farsani, and Sadegh Mirzamohammadi. "The effect of capsulated nanosilica-epoxy healing agents on the self-healing ability of glass fibers-epoxy composites under mechanical loading." Journal of Industrial Textiles 52 (August 2022): 152808372211198. http://dx.doi.org/10.1177/15280837221119833.

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In this study, the effect of using an epoxy healing agent containing silica nanoparticles instead of the neat epoxy healing agent on the self-healing ability of glass fibers/epoxy composites under the flexural, tensile and shear loadings was assessed. For doing this, in the first step, the silica nanoparticles (0, 1, 2 and, 3 wt.%) were dispersed into the ethyl acetate/epoxy healing agent. Then, these mixtures were encapsulated with the urea-formaldehyde polymer by an in-situ polymerization method. Finally, the glass fibers/epoxy composite containing 14 wt.% microcapsules along with 2 wt.% NiCl2(imidazole)4 catalyst were fabricated. To understand how the mechanical-healing behaviors of these composites under the various mechanical loads, these composites were destructed with a quasi-static penetration test for the creation of delamination damage. The healing process was done by the thermal activation method. The obtained results showed that the highest healing efficiency under the flexural, tensile and shear loads belonged to the composite containing 1 wt.% nanosilica into the healing agent, which were 89.8, 87.8, and 156.8%, respectively. The hackles of microcapsules, reduction in the thickness of microcapsules, formation of nanocomposite healing shell and the agglomeration of silica nanoparticles on the healed area were the influence factors on the healing ability of these composites. This work can give a view for healing the microcracks into composite structures by nanocomposite healing agents, which have the higher healing ability and better performance under mechanical loads than conventional healing agents.

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Song, Dowon, Taeseup Song, Ungyu Paik, Guanlin Lyu, Yeon-Gil Jung, Baig-Gyu Choi, In-Soo Kim, and Jing Zhang. "Crack-Resistance Behavior of an Encapsulated, Healing Agent Embedded Buffer Layer on Self-Healing Thermal Barrier Coatings." Coatings 9, no. 6 (May 31, 2019): 358. http://dx.doi.org/10.3390/coatings9060358.

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In this work, a novel thermal barrier coating (TBC) system is proposed that embeds silicon particles in coating as a crack-healing agent. The healing agent is encapsulated to avoid unintended reactions and premature oxidation. Thermal durability of the developed TBCs is evaluated through cyclic thermal fatigue and jet engine thermal shock tests. Moreover, artificial cracks are introduced into the buffer layer’s cross section using a microhardness indentation method. Then, the indented TBC specimens are subject to heat treatment to investigate their crack-resisting behavior in detail. The TBC specimens with the embedded healing agents exhibit a relatively better thermal fatigue resistance than the conventional TBCs. The encapsulated healing agent protects rapid large crack openings under thermal shock conditions. Different crack-resisting behaviors and mechanisms are proposed depending on the embedding healing agents.

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Pan, Changluan, Ping Tang, Martin Riara, Liantong Mo, Mingliang Li, and Meng Guo. "Effect of Healing Agents on Crack Healing of Asphalt and Asphalt Mortar." Materials 11, no. 8 (August 7, 2018): 1373. http://dx.doi.org/10.3390/ma11081373.

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This study investigated the effect of seven healing agents on crack healing ability of long-term aged asphalt and its mortar. Different healing agents including sunflower oil, aromatic oil, bitumen emulsion, and maltene-based emulsions were used. The crack healing of asphalt made use of two asphalt disk samples and healing was evaluated using direct tensile tests. For asphalt mortar, notched semi-circular samples were used. Test results indicated that the crack healing of asphalt and its mortar depended strongly on the type of healing agent. In general, asphalt healed faster than its mortar. Asphalt healing could be well improved by using oil agents, while asphalt mortar could be well healed with maltene-based emulsions. The crack healing of asphalt mortar developed rapidly followed by a steady state of increase. Initial crack healing using healing agents could be contributed by the diffusion and softening effects, which resulted in low strength recovery. Long term healing could lead to the bonding reconstitution in the cracks, which were decisive for the final strength gain. The promising healing agent should be able to achieve maximum strength recovery to resist cracking as well as a sufficient re-healing ability to deal with crack opening and closing.

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Mendelson, Myer D. "Psychoanalysis: Healing Agent or Catalyst?" Contemporary Psychoanalysis 31, no. 1 (January 1995): 106–12. http://dx.doi.org/10.1080/00107530.1995.10746898.

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Horrigan, Bonnie J. "Meaning as a Healing Agent." EXPLORE 8, no. 6 (November 2012): 323–25. http://dx.doi.org/10.1016/j.explore.2012.08.007.

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De Nardi, Cristina, Diane Gardner, and Anthony Duncan Jefferson. "Development of 3D Printed Networks in Self-Healing Concrete." Materials 13, no. 6 (March 14, 2020): 1328. http://dx.doi.org/10.3390/ma13061328.

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This paper presents a new form of biomimetic cementitious material, which employs 3D-printed tetrahedral mini-vascular networks (MVNs) to store and deliver healing agents to damage sites within cementitious matrices. The MVNs are required to not only protect the healing agent for a sufficient period of time but also survive the mixing process, release the healing agent when the cementitious matrix is damaged, and have minimal impact on the physical and mechanical properties of the host cementitious matrix. A systematic study is described which fulfilled these design requirements and determined the most appropriate form and material for the MVNs. A subsequent series of experiments showed that MVNs filled with sodium silicate, embedded in concrete specimens, are able to respond effectively to damage, behave as a perfusable vascular system and thus act as healing agent reservoirs that are available for multiple damage-healing events. It was also proved that healing agents encapsulated within these MVNs can be transported to cracked zones in concrete elements under capillary driving action, and produce a recovery of strength, stiffness and fracture energy.

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Yin, Tao, Min Zhi Rong, and Ming Qiu Zhang. "Self-Healing Epoxy Composites – Part II: Healing Performance." Advanced Materials Research 716 (July 2013): 387–90. http://dx.doi.org/10.4028/www.scientific.net/amr.716.387.

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Epoxy composites were provided with healing capability by pre-dispersing a novel repair system in the composites matrix cured by 2-ethyl-4-methylimidazole (2E4MIm). The healing agent consisted of ureaformaldehyde microcapsules containing epoxy and latent hardener CuBr2(2-MeIm)4 (the complex of CuBr2 and 2-methylimidazole). Single-edge notched bending (SENB) test were conducted to evaluate fracture toughness of the composites before and after healing. Moreover, healing efficiency was studied as a function of the content of the two-component healing agents. It was found that a healing efficiency of 173% relative to the fracture toughness of virgin composites was obtained in the case of 15 wt% epoxy-loaded microcapsules and 3 wt% CuBr2(2-MeIm)4.

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Napavichayanun, Supamas, Rungnapha Yamdech, Prompong Pienpinijtham, Teerapol Srichana, Siripich Chencharoenwong, Narendra Reddy, and Pornanong Aramwit. "Using polyvinyl alcohol-ionic hydrogels containing a wound healing agent to manage wounds in different environments." Journal of Wound Care 31, Sup8 (August 1, 2022): S12—S21. http://dx.doi.org/10.12968/jowc.2022.31.sup8.s12.

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Objective: To explore the effects of pH on properties of polyvinyl alcohol (PVA)-ionic hydrogels containing wound healing promoters. Method: PVA was combined with a natural wound healing promoter (silk sericin (SS)), and an anionic agent (eosin (ES)) or cationic agent (methylene blue (MB)), and made into hydrogels. Properties of the hydrogels and behaviour at different pHs were investigated. Results: The density and gel fraction of PVA/SS-ES hydrogel and PVA/SS-MB hydrogel were considerably lower compared with hydrogel without SS. The swelling ratio and degradation of the hydrogels increased with increasing SS concentration in all pH solutions. The influence of SS in interrupting long-chain PVA molecules was confirmed based on changes in Fourier-transform infrared spectroscopy (FTIR). The SS released from the gels was found to interact with the ionic agent and influenced the release profile of the ionic agent. Surprisingly, the anionic agent in PVA/SS-ES hydrogel showed 70% release in high pH solution whereas the cationic agent in PVA/SS-MB hydrogel showed 86% release in low pH solution. Moreover, the active agent could accumulate on the skin layer and had a positive effect on a specific wound area. Conclusion: Based on the results obtained in this study, it is suggested to use anionic hydrogels containing wound healing promoter for wounds at high pH and cationic hydrogels containing wound healing promoter for wounds with low pH. Ability to improve wound healing using a natural healing agent combined with ionic agents and controlling the pH of hydrogels will help in developing quick and low-cost treatment for wounds.

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Huang, Feng, and Shuai Zhou. "A Review of Lightweight Self-Healing Concrete." Materials 15, no. 21 (October 28, 2022): 7572. http://dx.doi.org/10.3390/ma15217572.

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Cementitious composites often crack because of their low tensile strength. The ability of self-healing cementitious composite to automatically repair cracks has attracted widespread attention. Lightweight aggregate (LWA) has a low density and a high porosity which can provide storage space for a healing agent. The healing mechanisms and healing compositions of lightweight self-healing concrete (LWSHC) have been summarized in this research. The workability, compressive strength, crack repairing, and durability of LWSHC performance is also illustrated. A LWA with interconnected pores and a high strength should be integrated into LWSHC to increase the crack closure rate and mechanical properties. Expanded perlite is the most suitable LWA carrier for bioremediation. The chemical healing agents are better than the biological healing agents at present since the biological healing agents have more negative effects. A sodium silicate solution is a good choice as a chemical healing agent. Vacuum conditions, high-temperature processing, and the use of coating technologies on LWAs can improve the healing effect of LWSHC. The addition of fibers also enhance the self-healing ability of LWSHC. Further, the use of numerical simulation supports the healing performance of LWSHC. The goal of this research is to investigate the most appropriate component of LWSHC to ensure a high crack closure rate, strength healing ratio, and great durability while being lightweight. It can then be adopted in high-rise and large-span concrete structures to extend the service life.

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Nakao, Wataru, Taira Hayakawa, Tesuro Yanaseko, and Shingo Ozaki. "Advanced Fiber Reinforced Self-Healing Ceramics for Middle Range Temperature." Key Engineering Materials 810 (July 2019): 119–24. http://dx.doi.org/10.4028/www.scientific.net/kem.810.119.

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The availability of TiC healing agent has been evaluated in low temperature self-healing behavior of Al2O3 based self-healing ceramics. For this purpose, some technical issues to actualize the advanced fiber-reinforced self-healing ceramics containing TiC based interlayer as healing agent were discussed. Especially, the mechanical matching between the matrix and the interlayer was focused. Moreover, the self-healing behavior of the advanced shFRC containing the optimized TiC based healing agent was investigated. As a result, 30 vol% TiC-70 vol% Al2O3 interlayer was confirmed to be the optimized healing agent in the self-healing ceramics, and the self-healing ceramics was found to enable to attain the perfect healing at 600°C within 10 min. And we succeeded in prototype production of fiber-reinforced self-healing ceramics for low pressure turbine blade.

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Md. Jamil, M. S., F. R. Jones, N. N. Muhamad, and S. M. Makenan. "Solid-state Self-healing Systems: The Diffusion of Healing Agent for Healing Recovery." Sains Malaysiana 44, no. 6 (June 1, 2015): 843–52. http://dx.doi.org/10.17576/jsm-2015-4406-10.

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13

Zhang, Ming, Feng Xing, Hong Zhi Cui, and Han Lu. "Study on Self-Healing Concrete with Pre-Embedded Healing Agent." Advanced Materials Research 250-253 (May 2011): 405–8. http://dx.doi.org/10.4028/www.scientific.net/amr.250-253.405.

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Self-healing concrete is a kind of smart concrete, and becoming one of research focus both in material and civil engineering field, in the paper, main self-healing methods concluded and partial technical problems of the self-healing facing, aim to these problems designed a kind of novel self-healing system, and experimental analyzed mechanism of self-healing.

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IIDA, Yuya, and Wataru NAKAO. "J044082 Self-healing ceramics containing with advanced self-healing agent." Proceedings of Mechanical Engineering Congress, Japan 2011 (2011): _J044082–1—_J044082–5. http://dx.doi.org/10.1299/jsmemecj.2011._j044082-1.

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15

Sun, Qian, Xin-Yu Wang, Sai Wang, Rong-Yue Shao, and Jun-Feng Su. "Investigation of Asphalt Self-Healing Capability Using Microvasculars Containing Rejuvenator: Effects of Microvascular Content, Self-Healing Time and Temperature." Materials 16, no. 13 (June 30, 2023): 4746. http://dx.doi.org/10.3390/ma16134746.

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The oily rejuvenator acted as the healing agent in microvasculars. A tensile test was designed to evaluate the self-healing efficiency of asphalt affected by microvascular number, self-healing time and temperature. It was found that the healing agent was slowly released through the microporous channels on the inner shell of the microvascular. The release modes of the agent can work together to improve the self-healing efficiency. The self-healing values of the three samples (asphalt, asphalt/microvasculars without rejuvenator and asphalt/microvasculars with rejuvenator) are 51%, 53%, and 71%. The self-healing capability of the asphalt samples with a healing agent is much greater than that of the other two without a healing agent at the same time. More microvascular rupture at the asphalt sample interface led to a higher self-healing efficiency. The self-healing efficiency values of the three samples (asphalt samples with one, two, and three microvasculars) are 52%, 67%, and 73%, respectively. The self-healing efficiency of the same sample increased during 1–3 days from 26% to 88% in one self-healing cycle. The self-healing efficiency value indicated that increasing the temperature improved each sample’s self-healing efficiency. The above trend of change also applies to the second self-healing process. A higher temperature reduces the resistance to molecular motion and accelerates the molecular action of bitumen and the healing agent. The time–temperature equivalence principle can be fully applied to comprehend asphalt self-healing.

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Sheng, S., K. K. Li, W. L. Chan, Z. Xiangjun, and D. Xianzhong. "Agent-Based Self-Healing Protection System." IEEE Transactions on Power Delivery 21, no. 2 (April 2006): 610–18. http://dx.doi.org/10.1109/tpwrd.2005.860243.

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17

Sun, Liying, Lan Xu, Fleetwood A. Henry, Sarah Spiegel, and Thor B. Nielsen. "A New Wound Healing Agent—Sphingosylphosphorylcholine." Journal of Investigative Dermatology 106, no. 2 (February 1996): 232–37. http://dx.doi.org/10.1111/1523-1747.ep12340570.

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Shim, Pil-Jong, Jae-Ho Park, Min-Sun Chang, Min-Jung Lim, Do-Ha Kim, Young Hoon Jung, Sang-Sup Jew, Eun Hee Park, and Hee-Doo Kim. "Asiaticoside mimetics as wound healing agent." Bioorganic & Medicinal Chemistry Letters 6, no. 24 (December 1996): 2937–40. http://dx.doi.org/10.1016/s0960-894x(96)00540-9.

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19

Akbik, Dania, Maliheh Ghadiri, Wojciech Chrzanowski, and Ramin Rohanizadeh. "Curcumin as a wound healing agent." Life Sciences 116, no. 1 (October 2014): 1–7. http://dx.doi.org/10.1016/j.lfs.2014.08.016.

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Benoit, J., A. Meddahi, N. Ayoub, D. Barritault, and A. Sezeur. "New healing agent for colonic anastomosis." International Journal of Colorectal Disease 13, no. 2 (May 14, 1998): 78–81. http://dx.doi.org/10.1007/s003840050139.

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Shin, Ki-Su, Byung-Chul Ryu, Xiao-Yong Wang, and Ki-Bong Park. "Self Healing System for Concrete Surface Crack using Polymer based Coating Agent Incorporating Microencapsulated Healing Agent." Journal of the Korea Institute of Building Construction 15, no. 6 (December 20, 2015): 579–87. http://dx.doi.org/10.5345/jkibc.2015.15.6.579.

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Shields, Yasmina, Tim Van Mullem, Nele De Belie, and Kim Van Tittelboom. "An Investigation of Suitable Healing Agents for Vascular-Based Self-Healing in Cementitious Materials." Sustainability 13, no. 23 (November 23, 2021): 12948. http://dx.doi.org/10.3390/su132312948.

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Self-healing cementitious materials can extend the service life of structures, improve safety during repair activities and reduce costs with minimal human intervention. Recent advances in self-healing research have shown promise for capsule-based and intrinsic healing systems. However, limited information is available regarding vascular-based self-healing mechanisms. The aim of this work is to compare different commercially available healing agents regarding their suitability in a self-healing vascular network system by examining a regain in durability and mechanical properties. The healing agents investigated include sodium silicate, two polyurethanes, two water repellent agents and an epoxy resin. Sealing efficiencies above 100% were achieved for most of the healing agents, and both polyurethanes and the epoxy resin showed high regain in strength. The results obtained from this study provide a framework for selecting a healing agent given a specific application, as a healing agent’s rheology and curing properties can affect the optimal geometry and design of a vascular network.

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HAYAKAWA, Taira, and Wataru NAKAO. "Self-healing behavior of Fiber Reinforced self-healing Ceramics using TiC healing agent layer." Proceedings of Mechanical Engineering Congress, Japan 2017 (2017): J0450201. http://dx.doi.org/10.1299/jsmemecj.2017.j0450201.

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Van Tittelboom, K., K. Adesanya, P. Dubruel, P. Van Puyvelde, and N. De Belie. "Methyl methacrylate as a healing agent for self-healing cementitious materials." Smart Materials and Structures 20, no. 12 (November 28, 2011): 125016. http://dx.doi.org/10.1088/0964-1726/20/12/125016.

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TAMAGAWA, Yuki, Hiroshi YO, and Wataru NAKAO. "New self-healing agent system for ceramics using self-healing improvers." Proceedings of the Materials and processing conference 2018.26 (2018): 821. http://dx.doi.org/10.1299/jsmemp.2018.26.821.

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Wong, Flora S. Y. "Use of Cleansing Agents at the Peritoneal Catheter Exit Site." Peritoneal Dialysis International: Journal of the International Society for Peritoneal Dialysis 23, no. 2_suppl (December 2003): 148–52. http://dx.doi.org/10.1177/089686080302302s31.

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Heavy bacterial colonization results in exit-site infection. Antiseptic and non antiseptic agents have both been used for exit-site cleansing. An ideal cleansing agent should not only reduce the number of microorganisms, but should also be harmless to the body's defenses and should not interfere with wound healing. In vitro studies using animal cells have demonstrated that some antiseptic agents have adverse effects on wound healing. Strong cytotoxic antiseptics should be discouraged in exit-site cleansing. In choosing an appropriate cleansing agent for exit-site care, the phase of wound healing, the condition of the exit site, and the goal of cleansing should be taken into consideration. Antimicrobial soap is recommended for cleansing a healed exit site, but biocompatible solution is preferred for the postoperative, infected, or traumatized exit site. In vivo studies on the effectiveness of some cleansing agents are still lacking, and clinical study of exit-site cleansing is needed to determine the most effective agents for the task.

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Mousavi, Seyyed-Mojtaba, Zohre Mousavi Nejad, Seyyed Alireza Hashemi, Marjan Salari, Ahmad Gholami, Seeram Ramakrishna, Wei-Hung Chiang, and Chin Wei Lai. "Bioactive Agent-Loaded Electrospun Nanofiber Membranes for Accelerating Healing Process: A Review." Membranes 11, no. 9 (September 13, 2021): 702. http://dx.doi.org/10.3390/membranes11090702.

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Despite the advances that have been achieved in developing wound dressings to date, wound healing still remains a challenge in the healthcare system. None of the wound dressings currently used clinically can mimic all the properties of normal and healthy skin. Electrospinning has gained remarkable attention in wound healing applications because of its excellent ability to form nanostructures similar to natural extracellular matrix (ECM). Electrospun dressing accelerates the wound healing process by transferring drugs or active agents to the wound site sooner. This review provides a concise overview of the recent developments in bioactive electrospun dressings, which are effective in treating acute and chronic wounds and can successfully heal the wound. We also discuss bioactive agents used to incorporate electrospun wound dressings to improve their therapeutic potential in wound healing. In addition, here we present commercial dressings loaded with bioactive agents with a comparison between their features and capabilities. Furthermore, we discuss challenges and promises and offer suggestions for future research on bioactive agent-loaded nanofiber membranes to guide future researchers in designing more effective dressing for wound healing and skin regeneration.

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Norambuena-Contreras, Jose, Luis E. Arteaga-Perez, Andrea Y. Guadarrama-Lezama, Rodrigo Briones, Juan F. Vivanco, and Irene Gonzalez-Torre. "Microencapsulated Bio-Based Rejuvenators for the Self-Healing of Bituminous Materials." Materials 13, no. 6 (March 22, 2020): 1446. http://dx.doi.org/10.3390/ma13061446.

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Asphalt self-healing by encapsulated rejuvenating agents is considered a revolutionary technology for the autonomic crack-healing of aged asphalt pavements. This paper aims to explore the use of Bio-Oil (BO) obtained from liquefied agricultural biomass waste as a bio-based encapsulated rejuvenating agent for self-healing of bituminous materials. Novel BO capsules were synthesized using two simple dripping methods through dropping funnel and syringe pump devices, where the BO agent was microencapsulated by external ionic gelation in a biopolymer matrix of sodium alginate. Size, surface aspect, and elemental composition of the BO capsules were characterized by optical and scanning electron microscopy and energy-dispersive X-ray spectroscopy. Thermal stability and chemical properties of BO capsules and their components were assessed through thermogravimetric analysis (TGA-DTG) and Fourier-Transform Infrared spectroscopy (FTIR-ATR). The mechanical behavior of the capsules was evaluated by compressive and low-load micro-indentation tests. The self-healing efficiency over time of BO as a rejuvenating agent in cracked bitumen samples was quantified by fluorescence microscopy. Main results showed that the BO capsules presented an adequate morphology for the asphalt self-healing application, with good thermal stability and physical-chemical properties. It was also proven that the BO can diffuse in the bitumen reducing the viscosity and consequently self-healing the open microcracks.

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Geng, Hai Ning, Na An, Rui Fang, and Qiu Li. "The Restoration of Compressive Strength of Self-Healing Mortar." Key Engineering Materials 726 (January 2017): 500–504. http://dx.doi.org/10.4028/www.scientific.net/kem.726.500.

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Self-healing mortar with various healing agent was prepared by sealing the healing agent in glass capsules. Waterglass, metakaolin slurry, and metakaolin slurry and waterglass were used as healing agent. The restoration of compressive strength of self-healing mortar was characterized by damaging the mortar at 7 and 28 days and curing for another 1, 7 and 28 days. The compressive strength of mortar with healing agent of waterglass was restored after curing for another 7 days under the condition of damaging at 7 or 28 days, and developed with a similar trend to that of the control specimen when damaged at 7 days but was not fully restored in the long term when damaged at 28 days. The compressive strength of mortar with healing agent of metakaolin or metakaolin and waterglass was restored after curing for another 7 days when damaged at 7 or 28 days, and developed with a similar trend to that of the control specimen in the long term under the condition of damaging at 7 or 28 days. Metakaolin slurry can restore the compressive strength of mortar at both early and later age damage. The combination of metakaolin and waterglass restored and further improved the compressive strength of self-healing mortar.

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Lim, Eng Har, and Kim Pickering. "Mechanical Properties of Self-Healing Carbon Fibre Fabric Reinforced Polymers (CFFRP)." Advanced Materials Research 700 (May 2013): 107–10. http://dx.doi.org/10.4028/www.scientific.net/amr.700.107.

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In this paper, carbon fibre fabric reinforced polymeric composites with the capability of self-healing were studied. These fabric-composite laminates were fabricated by hand lay-up of plain weave (PW) carbon fibre fabrics impregnated with polymer blends of epoxy resin and thermoplastic healing agent. Laminates containing different amounts of healing agent (0, 10wt% and 20wt% by weight of epoxy) were evaluated by tensile and three-point flexural tests according to the ASTM D3039/D3039M and D790, respectively. Aside of the potential for self-healing, benefits were found in terms of tensile and flexural properties. Overall, tensile properties were improved with addition of thermoplastic healing agent; the highest tensile strength and failure strain were obtained with the highest healing agent amount (20wt%) whilst the maximum tensile modulus was obtained at 10wt%. In general, flexural properties were also improved except flexural strain; the highest flexural strength and modulus were determined at 10wt%.

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Lusby, P. "Honey: A potent agent for wound healing?" Journal of WOCN 29, no. 6 (November 2002): 295–300. http://dx.doi.org/10.1067/mjw.2002.129073.

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Zhou, Shuai, Hehua Zhu, J. Woody Ju, Zhiguo Yan, and Qing Chen. "Modeling microcapsule-enabled self-healing cementitious composite materials using discrete element method." International Journal of Damage Mechanics 26, no. 2 (January 11, 2017): 340–57. http://dx.doi.org/10.1177/1056789516688835.

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Concrete with a micro-encapsulated healing agent is appealing due to its self-healing capacity. The discrete element method (DEM) is emerging as an increasingly used approach for investigating the damage phenomenon of materials at the microscale. It provides a promising way to study the microcapsule-enabled self-healing concrete. Based on the experimental observation and DEM, a three-dimensional damage-healing numerical model of microcapsule-enabled self-healing cementitious materials under compressive loading is proposed. The local healing effect can be simulated in our model, as well as the stress concentration effect and the partial healing effect. The healing variable of the DEM model is developed to describe the healing process. We examine the dependence of the mechanical properties of the microcapsule-enabled self-healing material on (a) the stiffness of the solidified healing agent, (b) the strength of the solidified healing agent, (c) the initial damage of specimens, and (d) the partial healing effect. In particular, the proposed numerical damage-healing model demonstrates the potential capability to explain and simulate the physical behavior of microcapsule-enabled self-healing materials on the microscale.

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Hamilton, A. R., N. R. Sottos, and S. R. White. "Pressurized vascular systems for self-healing materials." Journal of The Royal Society Interface 9, no. 70 (September 28, 2011): 1020–28. http://dx.doi.org/10.1098/rsif.2011.0508.

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An emerging strategy for creating self-healing materials relies on embedded vascular networks of microchannels to transport reactive fluids to regions of damage. Here we investigate the use of active pumping for the pressurized delivery of a two-part healing system, allowing a small vascular system to deliver large volumes of healing agent. Different pumping strategies are explored to improve the mixing and subsequent polymerization of healing agents in the damage zone. Significant improvements in the number of healing cycles and in the overall healing efficiency are achieved compared with prior passive schemes that use only capillary forces for the delivery of healing agents. At the same time, the volume of the vascular system required to achieve this superior healing performance is significantly reduced. In the best case, nearly full recovery of fracture toughness is attained throughout 15 cycles of damage and healing, with a vascular network constituting just 0.1 vol% of the specimen.

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Wang, Huoming, Miao Yuan, Jie Wu, Pei Wan, and Quantao Liu. "Self-Healing Properties of Asphalt Concrete with Calcium Alginate Capsules Containing Different Healing Agents." Materials 15, no. 16 (August 12, 2022): 5555. http://dx.doi.org/10.3390/ma15165555.

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Calcium alginate capsules encapsulating rejuvenator are a promising self-healing technology for asphalt pavement, but the effects of different healing agents on the self-healing performance of asphalt concrete has not been considered. In view of this, this paper aimed at exploring the effects of calcium alginate capsules containing different healing agents on the self-healing properties of asphalt concrete. Three types of capsules with sunflower oil, waste cooking oil and commercial rejuvenator were fabricated via the orifice-coagulation bath method and the interior structure, mechanical strength, thermal stability and oil content of the prepared capsules were characterized. The healing levels of asphalt mixtures with different capsules under different loading cycles and stress levels were evaluated. Furthermore, the saturates, aromatics, resins and asphaltenes (SARA) fractions and rheological property of extracted asphalt binder within test beams with different capsules after different loading conditions were assessed. The results indicated that all the three types of capsules meet the mechanical and thermal requirement of mixing and compaction of asphalt mixtures. The healing levels of test beams containing vegetable oil capsules were higher than that of waste cooking oil capsules and industrial rejuvenator capsules. The strength recovery ratio and fracture energy recovery ratio of test beams with vegetable oil capsules reached 82.8% and 96.6%, respectively, after 20,000 cycles of compressive loading at 1.4 MPa. The fracture energy recovery ratio of the waste cooking oil capsules also reached as high as 90%, indicating that waste cooking oil can be used as the healing agent of calcium alginate capsules to improve the self-healing property of asphalt mixture. This work provides a significant guide for the selection of healing agent for self-healing capsules in the future.

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Jefferson, Anthony, Tharmesh Selvarajoo, Brubeck Freeman, and Robert Davies. "An experimental and numerical study on vascular self-healing cementitious materials." MATEC Web of Conferences 289 (2019): 01004. http://dx.doi.org/10.1051/matecconf/201928901004.

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This paper gives an overview of a combined experimental-numerical study on vascular self-healing (SH) systems for cementitious composite materials. The work aimed to bridge the gap between numerical and experimental investigations for this type of SH system and to provide a set of data for developing, calibrating and validating a finite element model for these materials. The study investigated both healing-agent transport and mechanical damage-healing processes, including healing-agent curing. The experimental programme included mechanical tests on notched concrete beams and compact direct-tension specimens with inbuilt vascular healing systems, as well as tests to measure the transport properties of healing-agent within discrete concrete cracks and through the concrete matrix. The new coupled model employs elements with embedded strong discontinuities to simulate cracks and mechanical healing behaviour. A damage-healing constitutive model is described that simulates multiple damage-healing ‘events’. This mechanical model is coupled to discrete and continuum flow models that simulate healing-agent transport. The transport model accounts for pressurised and capillary flow, as well as curing-dependent flow properties. The main focus of this contribution is to show how these parallel programmes of work were combined so that the experimental observations guided the numerical developments and modelling questions were answered using experimental findings.

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Abdelhamid, Ahmed Maged, Nahla E. Zakzouk, and Samah El Safty. "A Multi-Agent Approach for Self-Healing and RES-Penetration in Smart Distribution Networks." Mathematics 10, no. 13 (June 29, 2022): 2275. http://dx.doi.org/10.3390/math10132275.

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Smart grid technology has gained much consideration recently to make use of intelligent control in the automatic fault-detection and self-healing of electric networks. This ensures a reliable electricity supply and an efficient operation of the distribution system against disasters with minimum human interaction. In this paper, a fully decentralized multi-agent system (MAS) algorithm, for self-healing in smart distribution systems, is proposed. The novelty of the proposed algorithm, compared to related work, is its ability to combine the zone and feeder agents, specified for system self-healing, with micro-grid agents. This enables the system to successfully achieve functions of fault locating and isolation along with service-restoration using expert rules while considering both operational constraint and load priorities. Meanwhile, managing the power flow and controlling the distributed generator (DG) contribution, in the considered network, is a bonus merit for the proposed algorithm. Hence, system self-healing as well as strengthening energy security and resiliency are guaranteed. The proposed algorithm is tested on a 22 kV radial distribution system through several case-studies with/without a DG wind-energy source. The employed agents are implemented in the Java Agent Developing Framework (JADE) environment to communicate and make decisions. Power system simulation and calculations are carried out in MATLAB to validate the agents’ decisions.

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Prošek, Zdeněk, Pavla Ryparová, and Pavel Tesárek. "Application of Bacteria as Self-Healing Agent for the Concrete and Microscopic Analysis of the Microbial Calcium Precipitation Process." Key Engineering Materials 846 (June 2020): 237–42. http://dx.doi.org/10.4028/www.scientific.net/kem.846.237.

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Cracks affect the durability of concrete by increasing its permeability. Self-healing materials can begin repairing themselves immediately after creating a crack. This is a big advantage of self-healing materials. In this study, effect of self-healing agents based on calcium carbonate precipitation for concrete is monitored for three months. Bacillus pseudofirmus was chosen as a self-healing agent and was tested on old cement pastes. Calcium precipitation was analyzed by scanning electron microscope with Energy-dispersive X-ray spectroscopy. The effect of added spontaneous calcination, culture media, bacteria and Ca2+ was monitored.

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Chiba, Makoto, Yuki Tsuji, Rin Takada, Yuri Eguchi, and Hideaki Takahashi. "Formation of Self-Healing Organic Coatings for Corrosion Protection of Al Alloys by Dispersion of Spherical and Fibrous Capsules." Materials 16, no. 8 (April 11, 2023): 3018. http://dx.doi.org/10.3390/ma16083018.

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In previous works, we developed a self-healing organic coating with dispersed spherical capsules for corrosion protection. The capsule consisted of a polyurethane shell and healing agent as the inner. When the coating was damaged physically, the capsules were broken, and the healing agent was released from the broken capsules to the damaged area. The healing agent could react with moisture in the air to form the self-healing structure and cover the damaged area of coating. In the present investigation, a self-healing organic coating with spherical and fibrous capsules was formed on aluminum alloys. The corrosion behavior of the specimen coated with the self-healing coating was examined in a Cu2+/Cl− solution after physical damage, and it was found that no corrosion occurred during the corrosion test. This is discussed in terms of the high healing ability of fibrous capsules as a result of the high projected area.

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Filatova, Darya. "MULTI-AGENT SIMULATION FOR SELF-HEALING MECHANISMS OF DAMAGED GEOTECHNICAL STRUCTURES." International Journal for Computational Civil and Structural Engineering 15, no. 4 (December 29, 2019): 48–57. http://dx.doi.org/10.22337/2587-9618-2019-15-4-48-57.

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The paper is devoted to the task of multi-agent modeling of self-healing mechanisms for the damaged surface of an abstract geotechnical structure using biotechnology. We consider two-component self-healing mechanism. The first one is presented as a dynamic stochastic model of the aggregated behavior of agents. The second one is described by the "game-of-life" principle. The principals of numerical modeling of both mechanisms are discussed and illustrated by different scenarios.

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Hanna, John, and Ahmed Elamin. "Computational Fracture Modeling for Effects of Healed Crack Length and Interfacial Cohesive Properties in Self-Healing Concrete Using XFEM and Cohesive Surface Technique." Computation 11, no. 7 (July 16, 2023): 142. http://dx.doi.org/10.3390/computation11070142.

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Healing patterns are a critical issue that influence the fracture mechanism of self-healing concrete (SHC) structures. Partial healing cracks could happen even during the normal operating conditions of the structure, such as sustainable applied loads or quick crack spreading. In this paper, the effects of two main factors that control healing patterns, the healed crack length and the interfacial cohesive properties between the solidified healing agent and the cracked surfaces on the load carrying capacity and the fracture mechanism of healed SHC samples, are computationally investigated. The proposed computational modeling framework is based on the extended finite element method (XFEM) and cohesive surface (CS) technique to model the fracture and debonding mechanism of 2D healed SHC samples under a uniaxial tensile test. The interfacial cohesive properties and the healed crack length have significant effects on the load carrying capacity, the crack initiation, the propagation, and the debonding potential of the solidified healing agent from the concrete matrix. The higher their values, the higher the load carrying capacity. The solidified healing agent will be debonded from the concrete matrix when the interfacial cohesive properties are less than 25% of the fracture properties of the solidified healing agent.

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Platonova, Elena, Polina Ponomareva, Zalina Lokiaeva, Alexander Pavlov, Vladimir Nelyub, and Alexander Polezhaev. "New Building Blocks for Self-Healing Polymers." Polymers 14, no. 24 (December 9, 2022): 5394. http://dx.doi.org/10.3390/polym14245394.

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The healing efficiency in self-healing materials is bound by the ability to form blends between the prepolymer and curing agent. One of the problems in the development of self-healing polymers is the reduced affinity of the bismaleimide curing agent for the elastomeric furan-containing matrix. Even when stoichiometric amounts of both components are applied, incompatibility of components can significantly reduce the effectiveness of self-healing, and lead to undesirable side effects, such as crystallization of the curing agent, in the thickness and on the surface. This is exactly what we have seen in the development of linear and cross-linked PUs using BMI as a hardener. In this work, we present a new series of the di- and tetrafuranic isocyanate-related ureas—promising curing agents for the development of polyurethanes-like self-healing materials via the Diels–Alder reaction. The commonly used isocyanates (4,4′-Methylene diphenyl diisocyanate, MDI; 2,4-Tolylene diisocyanate, TDI; and Hexamethylene diisocyanate, HDI) and furfurylamine, difurfurylamine, and furfuryl alcohol (derived from biorenewables) as furanic compounds were utilized for synthesis. The remendable polyurethane for testing was synthesized from a maleimide-terminated prepolymer and one of the T-series urea. Self-healing properties were investigated by thermal analysis. Molecular mass was determined by gel permeation chromatography. The properties of the new polymer were compared with polyurethane from a furan-terminated analog. Visual tests showed that the obtained material has thermally induced self-healing abilities. Resulting polyurethane (PU) has a rather low fusing point and thus may be used as potential material for Fused Deposition Modeling (FDM) 3D printing.

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Hu, Zun-Xiang, Xiang-Ming Hu, Wei-Min Cheng, Yan-Yun Zhao, and Ming-Yue Wu. "Performance optimization of one-component polyurethane healing agent for self-healing concrete." Construction and Building Materials 179 (August 2018): 151–59. http://dx.doi.org/10.1016/j.conbuildmat.2018.05.199.

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Su, Yen-Fang, Cihang Huang, HyunGu Jeong, Tommy Nantung, Jan Olek, Prince Baah, and Na Lu. "Autogenous healing performance of internal curing agent-based self-healing cementitious composite." Cement and Concrete Composites 114 (November 2020): 103825. http://dx.doi.org/10.1016/j.cemconcomp.2020.103825.

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Raimondo, M., P. Longo, A. Mariconda, and L. Guadagno. "Healing agent for the activation of self-healing function at low temperature." Advanced Composite Materials 24, no. 6 (October 7, 2014): 519–29. http://dx.doi.org/10.1080/09243046.2014.937135.

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Karger-Kocsis, J. "Self-healing properties of epoxy resins with poly(ε-caprolactone) healing agent." Polymer Bulletin 73, no. 11 (March 19, 2016): 3081–93. http://dx.doi.org/10.1007/s00289-016-1642-2.

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Roy, Rahul, Emanuele Rossi, Johan Silfwerbrand, and Henk Jonkers. "Encapsulation Techniques and Test Methods of Evaluating the Bacteria-Based Self-Healing Efficiency of Concrete: A Literature Review." Nordic Concrete Research 62, no. 1 (June 1, 2020): 63–85. http://dx.doi.org/10.2478/ncr-2020-0006.

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AbstractCrack formation in concrete structures due to various load and non-load factors leading to degradation of service life is very common. Repair and maintenance operations are, therefore, necessary to prevent cracks propagating and reducing the service life of the structures. Accessibility to affected areas can, however, be difficult as the reconstruction and maintenance of concrete buildings are expensive in labour and capital. Autonomous healing by encapsulated bacteria-based self-healing agents is a possible solution. During this process, the bacteria are released from a broken capsule or triggered by water and oxygen access. However, its performance and reliability depend on continuous water supply, protection against the harsh environment, and densification of the cementitious matrix for the bacteria to act. There are vast methods of encapsulating bacteria and the most common carriers used are: encapsulation in polymeric materials, lightweight aggregates, cementitious materials, special minerals, nanomaterials, and waste-derived biomass. Self-healing efficiency of these encapsulated technologies can be assessed through many experimental methodologies according to the literature. These experimental evaluations are performed in terms of quantification of crackhealing, recovery of durability and mechanical properties (macro-level test) and characterization of precipitated crystals by healing agent (micro-level test). Until now, quantification of crack-healing by light microscopy revealed maximum crack width of 1.80mm healed. All research methods available for assesing self-healing efficiency of bacteria-based healing agents are worth reviewing in order to include a coherent, if not standardized framework testing system and a comparative evaluation for a novel incorporated bacteria-based healing agent.

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Borges, João Lindolfo C., Anderson Freitas, and John P. Bilezikian. "Accelerated fracture healing with teriparatide." Arquivos Brasileiros de Endocrinologia & Metabologia 57, no. 2 (March 2013): 153–56. http://dx.doi.org/10.1590/s0004-27302013000200010.

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Satisfactory healing of the osteoporotic fracture is critically important to functional recovery, morbidity, and quality of life. Some therapies for osteoporosis may affect the processes associated with bone repair. For example, bisphosphonates in experimental models are associated with increased callus size and mineralization, reduced callus remodeling, and improved mechanical strength. Local and systemic bisphosphonate treatment may improve implant fixation. No negative impact on fracture healing has been observed, even after major surgery or when administered immediately after fracture. For the osteoanabolic agent teriparatide, case reports and a randomized trial have produced mixed results, but they are consistent with a positive impact of teriparatide on fracture healing. Some of the agents currently being developed for osteoporosis, notably sclerostin and DKK1 antibodies have shown a beneficial effect on fracture healing. At this point, therefore, there is no evidence that osteoporosis therapies are detrimental to fracture healing with some promising experimental evidence for positive effects on healing, notably for those agents whose actions are primarily anabolic.

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Hermawan, Harry, Peter Minne, Pedro Serna, and Elke Gruyaert. "Understanding the Impacts of Healing Agents on the Properties of Fresh and Hardened Self-Healing Concrete: A Review." Processes 9, no. 12 (December 7, 2021): 2206. http://dx.doi.org/10.3390/pr9122206.

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Self-healing concrete has emerged as one of the prospective materials to be used in future constructions, substituting conventional concrete with the view of extending the service life of the structures. As a proof of concept, over the last several years, many studies have been executed on the effectiveness of the addition of self-healing agents on crack sealing and healing in mortar, while studies on the concrete level are still rather limited. In most cases, mix designs were not optimized regarding the properties of the fresh concrete mixture, properties of the hardened concrete and self-healing efficiency, meaning that the healing agent was just added on top of the normal mix (no adaptations of the concrete mix design for the introduction of healing agents). A comprehensive review has been conducted on the concrete mix design and the impact of healing agents (e.g., crystalline admixtures, bacteria, polymers and minerals, of which some are encapsulated in microcapsules or macrocapsules) on the properties of fresh and hardened concrete. Eventually, the remaining research gaps in knowledge are identified.

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Sun, Qian, Xu Gao, Sai Wang, Rong-Yue Shao, Xin-Yu Wang, and Jun-Feng Su. "Microstructure and Self-Healing Capability of Artificial Skin Composites Using Biomimetic Fibers Containing a Healing Agent." Polymers 15, no. 1 (December 30, 2022): 190. http://dx.doi.org/10.3390/polym15010190.

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The aging and damage of artificial skin materials for artificial intelligence robots are technical problems that need to be solved urgently in their application. In this work, poly (vinylidene fluoride) (PVDF) fibers containing a liquid agent were fabricated directly as biomimetic microvasculars, which were mixed in a glycol–polyvinyl alcohol–gelatin network gel to form biomimetic self-healing artificial skin composites. The self-healing agent was a uniform-viscous buffer solution composed of phosphoric acid, acetic acid, and sodium carboxymethyl cellulose (CMC-Na), which was mixed under 40 °C. Microstructure analysis showed that the fiber surface was smooth and the diameter was uniform. SEM images of the fiber cross-sections showed that there were uniformly distributed voids. With the extension of time, there was no phenomenon of interface separation after the liquid agent diffused into the matrix through the fiber cavity. The entire process of self-healing was observed and determined including fiber breakage and the agent diffusion steps. XRD and FT–IR results indicated that the self-healing agent could enter the matrix material through fiber damage or release and it chemically reacted with the matrix material, thereby changing the chemical structure of the damaged matrix. Self-healing behavior analysis of the artificial skin indicated that its self-healing efficiency increased to an impressive 97.0% with the increase in temperature to 45 °C.

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Tan, Kun, Shuncheng Wu, and Shengduo Ding. "Carriers of Healing Agents in Biological Self-Healing Concrete." Advances in Materials Science and Engineering 2023 (April 27, 2023): 1–16. http://dx.doi.org/10.1155/2023/7179162.

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Concrete is the most widely used material in civil engineering, but due to its inherent brittleness, the generation of cracks easily occurs. Crack healing is an effective method for restoring the mechanical properties of concrete and improving its durability. Of all the current concrete crack healing methods, microbial-induced calcium carbonate precipitation technology is an incredibly promising crack self-healing strategy that has received widespread attention in the field of concrete crack repair. As the biological self-healing agent has difficulty resisting the high alkali and high calcium environment in concrete, protection is required when it is used in concrete cracks.

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Journal articles on the topic 'HEALING AGENT'

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