Visualization of self-healing materials by X-ray computed micro-tomography at UGCT

This work presents recent advancements in X-ray micro-computed tomography (XRMCT) of self-healing materials at Ghent University’s Centre for X-ray Tomography (UGCT). Results of XRMCT imaging in a self-healing polymer system are shown to demonstrate the use of XRMCT in self-healing studies. Furthermore, two new XRMCT scanners are presented. The HECTOR scanner was designed for large samples and strongly attenuating samples, and is therefore well suited to study self-healing concrete. The EMCT scanner is well suited for dynamic self-healing experiments in a controlled environment

Self-healing fuse

Fast-acting current limiting device provides current overload protection for vulnerable circuit elements and then re-establishes conduction path within milliseconds. Fuse can also perform as fast-acting switch to clear transient circuit overloads. Fuse takes advantage of large increase in electrical resistivity that occurs when liquid metal vaporizes

Self-Healing Computation

In the problem of reliable multiparty computation (RC), there are $n$ parties, each with an individual input, and the parties want to jointly compute a function $f$ over $n$ inputs. The problem is complicated by the fact that an omniscient adversary controls a hidden fraction of the parties. We describe a self-healing algorithm for this problem. In particular, for a fixed function $f$, with $n$ parties and $m$ gates, we describe how to perform RC repeatedly as the inputs to $f$ change. Our algorithm maintains the following properties, even when an adversary controls up to $t \leq (\frac{1}{4} - \epsilon) n$ parties, for any constant $\epsilon >0$. First, our algorithm performs each reliable computation with the following amortized resource costs: $O(m + n \log n)$ messages, $O(m + n \log n)$ computational operations, and $O(\ell)$ latency, where $\ell$ is the depth of the circuit that computes $f$. Second, the expected total number of corruptions is $O(t (\log^{*} m)^2)$, after which the adversarially controlled parties are effectively quarantined so that they cause no more corruptions.Comment: 17 pages and 1 figure. It is submitted to SSS'1

Vascular self-healing of a reinforced concrete beams under 4-point bending

Self-healing materials are inspired on self-healing capabilities of living organisms. For plants, animals and people, the vascular system that distributes nutrients to all parts of the organism is also key for the self-healing capability. In a concrete element, a self-healing approach with an incorporated vascular system possess advantages towards repeatable self-healing and controlled placement of the self-healing system in the areas of interest. This study presents such a vascular system, which is designed to be accessible from outside of the concrete beam. Both clay and inorganic phosphate cement are compared as materials for the vanes of this system. The specimen contain steel reinforcement and are tested by means of 4-point bending, in order to obtain realistic conditions. Ease of construction and placement are discussed. From the experiments it can be seen that repeatable selfhealing is possible, that the system is able to heal multiple cracks at the same time and that cracks can be sealed and mechanical properties restored

Enhanced self-healing capacity in cementitious materials by use of encapsulated carbonate precipitating bacteria : from proof-of-concept to reality

In this study, two bacteria-based self-healing systems were developed for the proof-of-concept and approach to a realistic self-healing. A self-healing system with glass capillaries and silica sol gel carried bacterial cells was first built. The bio-CaCO3 formed in-situ (in silica gel) after glass capillaries breakage preliminarily showed the feasibility of this system. The investigation on the selfhealing efficiency demonstrated that the water permeability was decreased by about two orders of magnitude due to self-healing. However, practical application of this system was limited by the use of the un-mixable and expensive glass capillaries. A second self-healing system therefore was built in order to approach a realistic self-healing, by using hydrogel encapsulated bacteria. Great superiority in healing efficiency was obtained in this system. A maximum crack width of 0.5 mm could be healed within 7 days in the specimens of the bacterial series; while the maximum crack width can be healed in other series was in the range of 0.2~0.3 mm. Water permeability was greatly decreased (68%) in the bacterial series

ETS (Efficient, Transparent, and Secured) Self-healing Service for Pervasive Computing Applications

To ensure smooth functioning of numerous handheld devices anywhere anytime, the importance of self-healing mechanism cannot be overlooked. Incorporation of efficient fault detection and recovery in device itself is the quest for long but there is no existing self-healing scheme for devices running in pervasive computing environments that can be claimed as the ultimate solution. Moreover, the highest degree of transparency, security and privacy attainability should also be maintained. ETS Self-healing service, an integral part of our developing middleware named MARKS (Middleware Adaptability for Resource discovery, Knowledge usability, and Self-healing), holds promise for offering all of those functionalities

Unraveling beam self-healing

We show that, contrary to popular belief, non only diffraction-free beams may reconstruct themselves after hitting an opaque obstacle but also, for example, Gaussian beams. We unravel the mathematics and the physics underlying the self-reconstruction mechanism and we provide for a novel definition for the minimum reconstruction distance beyond geometric optics, which is in principle applicable to any optical beam that admits an angular spectrum representation. Moreover, we propose to quantify the self-reconstruction ability of a beam via a newly established degree of self-healing. This is defined via a comparison between the amplitudes, as opposite to intensities, of the original beam and the obstructed one. Such comparison is experimentally accomplished by tailoring an innovative experimental technique based upon Shack-Hartmann wave front reconstruction. We believe that these results can open new avenues in this field

Self-Healing Tile Sets

Biology provides the synthetic chemist with a tantalizing and frustrating challenge: to create complex objects, defined from the molecular scale up to meters, that construct themselves from elementary components, and perhaps even reproduce themselves. This is the challenge of bottom-up fabrication. The most compelling answer to this challenge was formulated in the early 1980s by Ned Seeman, who realized that the information carried by DNA strands provides a means to program molecular self-assembly, with potential applications including DNA scaffolds for crystallography [19] or for molecular electronic circuits [15]. This insight opened the doors to engineering with the rich set of phenomena available in nucleic acid chemistry [20]