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Experimental Study on the Behaviour of Self Healing Concrete using Silicagel in Microcapsules as a Healing Agent

Experimental Study on the Behaviour of Self Healing Concrete using Silicagel in Microcapsules as a Healing Agent

In order to overcome this problem, a variant of smart concrete is rapidly developing, which is known as “Self- healing concrete”. The self-healing concrete is one that senses its crack formation and reacts to cure itself without human intervention. The available self-healing agents are polyurethane, silica gel, fly ash, ceramic tubes, blast furnaces, bacteria, calcium sulfo aluminate and crystalline additive, and geo materials. The self-healing mechanism of silica gel – crack ruptures the capsules and the healing agent contacts the catalyst, triggering polymerization that bonds the crack faces. When crack appears, the capsules rupture and the healing mechanism starts also the strength has been regained.
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Advances in self-healing supramolecular soft materials and nanocomposites

Advances in self-healing supramolecular soft materials and nanocomposites

on two components. First, micro-containers of healing agents that may be in the form of microcapsules [4], or hollow fibers [11] and second, a catalyst dispersed within the polymer matrix. Upon mechanical damage, self-heal- ing can be initiated as micro-containers upon ruptured, causing healing agents to be released into the cracks via capillary motion. When the released healing agents come into contact with the dispersed catalyst, polymerization takes place via catalytic crosslinking, re-bonding happens on the crack sites [12]. While extrinsic self-healing meth- ods allow instantaneously healing and are closer to com- mercialization as no changes to the molecular structure are required; they can only be utilized once or limited amount at each location because of the exhaustion of the micro-containers [13]. Therefore, to overcome this limi- tation, intrinsic self-healing has often been sought after, as they have been designed with the ability to sustain multiple healing cycles.
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Methods for Self-Healing based on traces and unsupervised learning in Self-Organizing Networks

Methods for Self-Healing based on traces and unsupervised learning in Self-Organizing Networks

self-healing systems. Then, as a second important contribution of this paper, a diagnosis system that reasons in a similar way to cellular network troubleshooting experts have been devised, by following the methodology proposed in the first part of the paper. This system identifies the cause of the problems by applying a set of fuzzy rules to the KPIs. The main advantage of using fuzzy logic is that troubleshooting experts can easily understand and interpret the results and the behavior of the system. In addition, evaluation results show that the defined fuzzy system provides fault identification with high success rate. This system and the Fault Model have been tested over a dynamic system-level LTE simulator, emulating the behavior of the network in the presence of faults and thus generating an artificial dataset composed of labeled cases. In particular, in this paper, two datasets have been obtained, one using a hexagonal scenario and one using an irregular scenario which is based on a real LTE network. Those datasets are shared online [47] in order to cover the lack of labeled cases and allow research community to replicate and compare the experiments. Furthermore, some examples of how the diagnosis system works in a live network have been discussed.
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Self Healing Cocrete

Self Healing Cocrete

Concrete, it is the most widely used material for the construction. Concrete is weak in tension and strong in compression and cracks are inevitable in concrete. Once cracks form in concrete it may reduce the lifespan of the concrete structures. Micro-cracks and pores in concrete are highly undesirable because they provide an open pathway for the ingress of water and deleterious substances which leads to the corrosion of reinforcement and reduces the strength and durability of concrete. Various repair techniques are available to repair the cracks, but they are highly expensive and time consuming process. There are moderate techniques to repair the cracks in concrete by itself called Self-Healing Concrete. This bacterial remediation technique surpasses other techniques as it is bio-based, eco-friendly, cost-effective and durable. Concrete is a highly alkaline material, the bacteria added is capable of withstanding alkali environment. Bacteria with calcium nutrient source are added into the concrete at the time of mixing. If any cracks will be formed in concrete, bacteria precipitate calcium
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On  the  Security  of  a  Self-healing  Group  Key  Distribution  Scheme

On the Security of a Self-healing Group Key Distribution Scheme

Recently, in Journal of Security and Communication Networks (5(12):1363-1374, DOI: 10.1002/ sec.429), Wang et al. proposed a group key distribution scheme with self-healing property for wireless networks in which resource is constrained. They claimed that their key distribution scheme satisfies forward security, backward security and can resist collusion attack. Unfortunately, we found some security flaws in their scheme. In this paper, we present a method to attack this scheme. The attack illustrates that this scheme does not satisfy forward security, which also directly breaks the collusion resistance capability.
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Self healing of
composite material
with an intermediate
supramolecular
layer

Self healing of composite material with an intermediate supramolecular layer

8 dependent viscosity function determined during forced harmonic oscillation of shear stress. The main parts of this rheometer consists of 2 plates which are parallel to each other, one being stationary, the other able to rotate. A casing was put around this plates to control the temperature during testing. A sample of SP1 was placed on the bottom plate of the two parallel plate and the temperature was elevated until this sample is liquid. By reducing the gap between the plates and measuring the force at a certain angular frequency for the rotating plate, the viscosity of the sample at the given temperature was determined. The results are depicted in the two graphs Graph 2.1 and Graph 2.2. The two graphs clearly shows that the viscosity decreases as a function of temperature. Based on those results a temperature of between 100 °C and 140 °C will be used at production of the supramolecular intermediate layer, production of samples with supramolecular intermediate layer and healing process. A temperature higher than 140 °C is not used because at temperature near 150 °C the SP1 material will decompose and so losing its self-healing capacity for ever. [13,14]
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LTE Handover Parameter Optimization for Self Configuring and Self Healing Networks

LTE Handover Parameter Optimization for Self Configuring and Self Healing Networks

parameters for LTE Handover. Self-Configuring and Self- Healing networks are considered, and parameter optimization is done for the same considering Omnidirectional, Patterned ASCII 2D, Patterned ASCII 3D, Patterned NSMA antennas .The result of optimization is shown in terms of Throughput and Network delivery delay for each of the antennas. Conclusions are drawn out by comparing all the antennas and results are tabulated.

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Study on Self Healing Concrete by Bacterial Media

Study on Self Healing Concrete by Bacterial Media

Concrete is a vital building material that is an absolutely essential component of public infrastructure and most buildings. Concrete will continue to be the most important building material for infrastructure but most concrete structures are prone to cracking. Tiny cracks on the surface of the concrete make the whole structure vulnerable because water seeps in to degrade the concrete and corrode the steel reinforcement, greatly reducing the lifespan of a structure. Concrete can withstand compressive forces very well but not tensile forces. When it is subjected to tension it starts to crack, which is why it is reinforced with steel; to withstand the tensile forces. Structures built in a high water environment, such as underground basements and marine structures, are particularly vulnerable to corrosion of steel reinforcement. Motorway bridges are also vulnerable because salts used to de-ice the roads penetrate into the cracks in the structures and can accelerate the corrosion of steel reinforcement. Self-healing concrete 3 in general seeks to rectify these flaws in order to extend the service life of any given concrete structure. In general bacteria is induced in the form of pellets in concrete size ranges from 2 to 4mm. They are induced in the ratio of 20% to the total volume of concrete, they are clay pellets made of clay, bacteria 1 and food for bacteria (calcium lactate).It will comprise the volume of the harder material of concrete that is coarse aggregate, as bacterial pellets are not as hard as aggregate they will show impact on the designed strength. So the concrete is designed for higher grades than required, it will be a economical backdrop if the concrete is designed so. In this project the bacteria 2 is induced in water that used for making concrete, the culture of bacteria is introduced in water used for making and kept aside for some days to allow bacteria to develop, then the bacteria induced water is used for making the concrete.
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Self Healing MIMO Transreceiver Module On Chip

Self Healing MIMO Transreceiver Module On Chip

The transmitter acts under the physical layer of OSI model. It enhances the error detection and control mechanisms using LRC. It reads the input frames given by the user and converts into a framing sequence. The Arm processor is configured to act as a error detection and correction unit for the physical layer [6]. The hardware (Figure 3) functions as a self-healing physical layer implementation in future embedded web server. The Receiver receives the information, detects and corrects errors and retransmits it to the side-by-side configured server system. The hardware implementation of the error recovery block on the ARM processor along with the data recovered output is shown in appendix -1.
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A Self-healing Architecture based on RAINBOW for Industrial Usage

A Self-healing Architecture based on RAINBOW for Industrial Usage

This task which will be inserted into the system will be done by adaptation infrastructure. RAINBOW frame- work also includes translation and architecture parts in infrastructure module. The translation module is used for transforming the structure of the information that comes from the environment into the information which can be understood by another part of self-healing architecture. This transformation of information is the reason of RAINBOW framework reusability feature. In architecture module, there are four main elements; Model man- ager, constraint evaluator, adaptation engine and adaptation executor. The required knowledge for changing the system is known as system specific knowledge; Using this knowledge and also defining mappings, types and properties, rules, strategies and tactics and operators will make the system capable of responding to the case[15]. This information and data are necessary to this system and could be considered as knowledge. In RAINBOW architecture, after detecting information and conditions according to resources by the probe, they are reported to the architecture layer by knowledge and resource discoveries and in between; transforming this information into comprehensible information for the architecture layer is carried out using existing rules in mapping mod- ule. Then, information is aggregated by gauges and is transformed to the environment model by the model manager. Next, limitations are checked by the analyzer and if necessary, it will send an adaptation request to the adaptation manager and after explaining the adaptation strategy, adaptation manager will provide the strategy to the change executer. The applied result to the system layer will be translated into the system level by the translator and then it will be sent.
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Comparative Study of Self Healing Concrete & Traditional Concrete

Comparative Study of Self Healing Concrete & Traditional Concrete

Concrete test specimens were prepared in which the part of a aggregate material, i.e. the 2-4 mm size class, was replaced by the similarly sized expanded clay particles loaded with the biochemical self-healing agent (bacterial spores 1.7x105 g-1 expanded clay particles, corresponding to 5x107 spores dm-3 concrete, plus 5% w/w fraction calcium lactate, corresponding to 15g dm-3 concrete). Before application, loaded expanded clay particles were oven-dried until no further weight loss due to water evaporation was observed (one week at 40ºC). Control specimens had a similar aggregate of the composition but these expanded clay particles were not loaded with the bio-chemical agent. Both the types of expanded clay particles (empty for the control specimens and loaded for the bacterial specimens) The amount of light weight aggregate applied in this case represents 50% of the total aggregate volume. Replacement of the such a high fraction of the sand and gravel for expanded clay has consequences for strength characteristics of the derived concrete. In this specific case of a 50% decrease in compressive strength was observed after 28 days curing when compared to specimens of similar aggregate composition without replacement of sand and gravel fractions for expanded clay particles.
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Evaluation Techniques for the Corrosion Resistance of Self-Healing Coatings

Evaluation Techniques for the Corrosion Resistance of Self-Healing Coatings

Self-healing coatings are a robust method of corrosion protection that can autonomically repair damage and prolong the useful life of the coating. Evaluation of the performance of self-healing coatings can be performed either globally or locally. The main disadvantages of the techniques used in evaluating self-healing performance are as follows: complexity in obtaining a stable potential due to the non-electrochemical nature of the coating as in OCP, limitations arising from the concentration polarization and IR drops as in PP and difficulty in the proper construction of the equivalent circuits as in the EIS. The electrochemical techniques PP and EIS provide quantitative results about the self- healing process where the protection efficiency and the rate of corrosion and therefore the rate of self- healing can be calculated using these techniques. These methods provide global information about the self-healing process and do not provide details of the local reactions occurring at the damage site. On the other hand, addressing the processes occurring locally at the solid/liquid interfaces may provide a key for investigating the mechanisms of the respective electrochemical reactions as well as the active species involved in the latter. For instance, SVET can measure the local distribution of fluxes but cannot differentiate the nature of the species that are responsible for generating the electric field. SIET can investigate the local activity of different ionic species however, it detects only a single specific ion in the medium. Therefore, a combination of SVET and SIET provides a powerful way of investigating both the distribution and type of the active species involved in the electrochemical process. Although, LEIS can probe valuable information about the changes of the impedance in a small area, it does not give information about the topology of the surface. SECM is capable of providing valuable information about the topology of the surface, it is highly specific and able to provide measurements of the smaller and faster phenomena. Moreover, SECM can give information about the kinetics and mechanisms of the electrochemical processes and therefore considered one of the best techniques for self-healing coating evaluation.
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Simulation Research of Self-healing Mechanism for Microcapsule Composite

Simulation Research of Self-healing Mechanism for Microcapsule Composite

Illuminated by organism’s self-healing up phenomenon, microcapsules filled with healing liquid are embedded in composite materials. When cracks travel through microcapsules, stress at the crack end is concentrated and microcapsule breaks, and then the encapsulated liquid runs out to fill the crack by the capillary effect and polymerizes with catalyst in the composite. As a result, the crack is healed and underlying dangerous defects are removed. Material intensity and life-span are enhanced [3].

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Durability and Self- Healing Behaviour of Bacterial Impregnated Concrete

Durability and Self- Healing Behaviour of Bacterial Impregnated Concrete

After 100 days of curing 0.1mm crack width healed completely (Fig.1) whereas 0.5 mm crack width reduced to 0.42mm, 0.45mm to 0.4mm and 0.22mm to 0.15mm. The self-healing process seems like slow process but it is more sustainable and also it provides long term efficiency. After 100 days of curing specimen with 0.1mm crack width healed completely.

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An Overview on Fungi as Self Healing Agent in Biomineralization of Calcite

An Overview on Fungi as Self Healing Agent in Biomineralization of Calcite

bacteria have gained a great success and popularity as beginners in achieving the ultimate goal of healing the cracks formed in fresh concretes. But, it appears that still they are bound with some restrictions. Therefore, the present paper deals with the study of a new self healing agent named fungi have been explored to heal the cracks in concrete infrastructures. In this study, a novel self-healing approach is discussed, in which fungi like Trichoderma reesei and many others are used to heal concrete cracks by promoting CaCO 3 precipitation. This is also called as microbiologically induced
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Influence of Functionalization of Nanocontainers on Self-Healing Anticorrosive Coatings

Influence of Functionalization of Nanocontainers on Self-Healing Anticorrosive Coatings

454 release of inhibitor and self-healing protection for a long serving 455 time (Figure 10b). The double layer capacitance (C dl ), on the 456 other hand, is directly related to the metal area exposed to the 457 electrolyte, therefore providing information about the wet 458 adhesion of the coating to the metal. A high C dl value always 459 accounts for a high extent of corrosion and a high degree of 460 coating degradation or worse adhesion of the coating to the 461 metal surface. The highest C dl value (21 × 10 −6 F cm −2 ) for the 462 coating containing C-L FSNs 2 is consistent with lowest R ct 463 value (0.34 × 10 5 Ω cm 2 ) among all samples and severe pit-like 464 defects shown in Figure 8c. For the coating doped with C-L 465 FSNs 5, the lowest value of C dl after 7 immersion weeks can be 466 attributed to good adhesion of the coating to the metal surface 467 and suppressed corrosion evolution by self-healing ability of the 468 coating. Overall, the EIS study con fi rms the better anticorrosive
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A cohesive-zone crack healing model for self-healing materials

A cohesive-zone crack healing model for self-healing materials

The concept of self-healing is a promising path to enhance the damage tolerance and extend the lifetime of structural and functional materials. Research in the last decade has shown that self-healing mechanisms can be incorporated in various material classes ranging from polymers to high temperature ceramics [1]. A classical example of an extrinsic self- healing mechanism is based on healing capsules (particles) dispersed within the base (or matrix) material as shown in Fig. 1a. In an extrinsic system, the healing process is typically activated by cracks that interact with the capsules [2, 3, 4]. Such capsule-based self-healing mechanism finds its application in materials that otherwise do not possess the capacity to repair damage. Other extrinsic self-healing materials involve hollow fibers filled with healing agents [5, 6] and microvascular networks with distributed healing agents [7]. Among the extrinsic self-healing mechanisms, the encapsulated particle-based system has been widely investigated [8, 9, 10]. The encapsulation-based healing concept may lead to a desirable autonomous self-healing behavior for the system (base material plus healing agent), but it is typically limited by the finite amount of the healing agent which often precludes multiple healing, at least in the location where the healing agent has been consumed. Microvascular network-based self-healing systems offer the possibility of multiple healing after repeated damage events by enhancing the supply of the healing agent. In contrast with extrinsic self-healing material systems, in intrinsic self-healing materials the healing action is due to the physio-chemical nature of the material itself, as illustrated in Fig.1b [11]. Such materials have the natural capability of repairing the damage more than once [12].
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Self-Healing in Web Services Using Genetic Algorithm

Self-Healing in Web Services Using Genetic Algorithm

A self-healing system should recover from the abnormal or unhealthy state and return to the normative healthy state, and function as it was prior to disruption (Harald and Schahram, 2010). The specification to which a system has been built is usually not fully known to those who maintain it. It is difficult to draw a discrete difference between healthy and unhealthy states of a system as the transition in between the two states is not abrupt. What generally obtains is a gradual transition from one state to another (Debanjan et al., 2006). Also, because web services are dynamic and unpredictable, one of their big challenges - quality of service- is in attention. Response time is one of the qualities of service parameters of which its increment is in inverse proportion to system performance. In degraded transition, response time increases continuously until it is not able to respond. There are several approaches that have been developed to achieve self-healing service-oriented systems. Some approaches implement self-healing after the detection of failures. When an error occurs, it stops currently running services and repairs or replaces the malfunctioned ones. A major issue with these reactive approaches is that they cause long disruptions of currently running service systems, which in most cases will incur high revenue cost or risk to lose a large number of customers (Hongbing et al., 2009).
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A survey of self healing systems frameworks

A survey of self healing systems frameworks

Performance tiering is a self-healing methodology used to divide systems and service health into levels [38, 41]. These levels in turn are used to understand QoS changes and instantiate behaviours that maximise the usage available resources. Arguably, the most direct approach to defining service levels is to use statically assigned resource constraints. Each level corresponds to a set of QoS metrics or fitness criteria that tells the system when to dynamically reduce content fidelity [41]. Primary developed for front-end web-services, static service tiering requires a human-supplied policy to determine when content fidelity can either be reduced or increased. In contrast, allowing policies to dynamically set thresholds for self-healing behaviours can have more autonomous results [29, 38, 42, 50, 59]. The Shadows framework, for example, uses a set of SLA’s and utility policies to automatically generate behavioural expectations of a system. This allows the system to perform more in line with human-readable goals, such as cost, average service time, and other criteria instead of discrete metrics. It then combines this information with historical performance data to provide internal revalidation of recovery solutions. By using a time windowed mean expectations in behaviour can allow for elasticity versus pre-defined QoS metrics.
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Strength properties of self-healing mortars

Strength properties of self-healing mortars

25. Li, V. C., Sakulich, A. R., Reinhardt, H. W., Schlangen, E., Van Tittelboom, K., Snoeck, D., & Nishiwaki, T. (2013). Recovery against Mechanical Actions. In Self-Healing Phenomena in Cement-Based Materials (pp. 119- 215). Springer Nether.

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