Nowadays, they are used in sectors such as optics, among others. They change their properties when exposed to a magnetic field. For example, they are currently used in shock absorbers to prevent seismic vibrations in bridges or skyscrapers.
There are several types: electroluminescents emit light when they are fed with electrical impulses, fluorescents reflect light with greater intensity and phosphorescents are able to emit light after the initial source has ceased. Materials science is a constant supply of news about new discoveries that could revolutionise our future.
We review some of the most amazing materials from recent years below:. In addition, there are other materials that have made headlines in recent years. These include stanene, which could be the super condenser of the future; silicone, which many compare to graphene; vanadium dioxide, with an ability to transit electricity without emitting heat, which promises to revolutionise electronics; and thermochromic cement and self-repairing concrete, intended to increase the energy efficiency of housing and the life span of buildings respectively.
One of the areas of research where materials science has advanced most in recent years is in the development of new materials for use in 3D printing, which is already used in sectors as diverse as design, medicine, architecture and food. The most widely used are thermoplastics, especially polylactic acid PLA and acrylonitrile butadiene styrene ABS , which are used in mobile phone casings, toys and car bodies. Smart materials are also starting to be printed thanks to 4D printers.
Share in Twitter. Share in Facebook. Whatsapp Whatsapp. Materials science is a continual source of discoveries that could revolutionise our future. Among them, the following should be highlighted: Piezoelectric materials They can convert mechanical energy into electrical energy and vice versa. Shape memory materials They have the ability to change the shape, even returning to their original shape, when exposed to a heat source, among other stimuli. Chromoactive materials They change colour when subjected to a certain variation in temperature, light, pressure, etc.
Magnetorheological materials They change their properties when exposed to a magnetic field. Photoactive materials There are several types: electroluminescents emit light when they are fed with electrical impulses, fluorescents reflect light with greater intensity and phosphorescents are able to emit light after the initial source has ceased. We review some of the most amazing materials from recent years below: Synthetic spider web. This material is not only five times stronger than steel, but also has great elasticity.
Its potential uses include: bulletproof clothing, artificial skin for burns or waterproof adhesives. Its main component is chitin, a carbohydrate found in krill shells. Mechanical Properties 3. The procedure procedure involves involves executing executing a bending test Figure 2a in order to evaluate the indirect tensile strength. Then, a bending test Figure 2a in order to evaluate the indirect tensile strength. Specifically, Specifically, three bending three bending tests and tests and tests six compression six compression were performed tests forwere eachperformed product mix.
Table 2 highlights the results obtained, evaluated as the average of the values highlights the results obtained, evaluated as the average of the values of all the tests of all the tests carried out. In general, the results show how the addition of PCM reduces carried out. In general, the results show how the addition of PCM reduces the mechanical the mechanical performance of the mix compared to the traditional compound.
Despite performance of the mix compared to the traditional compound. Table 2. Results of the mechanical tests for the two mixes. Thermal Properties Table 2. The control system drives the cartridge heaters in the LabView environment using a proportional—integral—derivative PID control.
As the electric resistance of the cartridge is known, the current measurement provides the heat flux due to the Joule effect. The sample surface temperatures are determined by three sensors positioned on the two sides.
EN [26] is the standard that defines the thermal conductivity measurement with the guarded hot plate and the conditioning process of the sample before the test. Figure 3. Section of the guarded hot plate apparatus. EN [26] is the standard that defines the thermal conductivity measurement with the guarded hot plate and the conditioning process of the sample Figure 3.
The results of the thermal analysis executed on the sample Figure 4 are reported in The results of the thermal analysis executed on the sample Figure 4 are reported The control system drives the cartridge heaters in the LabView environment using a Table 3. The results of the thermal analysis executed on the sample Figure 4 are reported in Table 3.
Figure 4. Sample during the hot-plate analysis. Table 3. Thermal flux supplied to the metering zone 5. Figure 5. Differential scanning calorimeter test results of the PCM. Discussion 4. Mechanical Properties 4. Mechanical Properties The The mechanical tests mechanical performed tests on the performed on prismatic specimens the prismatic highlight specimens how the how highlight strengththe decreases as the PCM ratio increases.
Considering considered suitable for masonry structures and may be classified as M5 and M15 Table that the Italian Technical Standards for Buildings [32] require that the mortar must have a 3. Considering that the Italian Technical Standards for Buildings [32] require that the minimum compressive strength of 2.
Lower strength require- cementitious mortar generally has a compressive strength higher than 8. Different considerations may be made about the employment of these mixes for the repair of concrete structures. In fact, the classification given by the EN stan- dard [34] requires very high strength for both structural and nonstructural use.
Comparing the data obtained from the experimentation with those present in the literature it is possible to evaluate how, although there are some differences, it is possible to find similarities Table 5. Materials , 14, 8 of 11 Table 4. Comparative table between data in the literature and data obtained with experimentation, with medium indirect tensile strength 1 and medium compressive strength 2.
Thermal Properties The mix shows good behavior in terms of insulating properties, in good agreement with the literature outcomes [19], confirming thermal conductivity values typical of light- ened mixtures, as reported in [35], where the thermal conductivity values span from 0. The hot-plate tests underline a light increase in the thermal conductivity in the tem- perature range where the PCM is completely solid, with respect to the zone where it is found in the liquid state, again confirming results that have already been obtained by other researchers.
Therefore, the heat storage capacity of the PCM is completely exploited in a consider- able fraction of the year. Conclusions The evidence of climate change and the serious consequences associated with it require a radical rethinking of urban settlements, buildings and construction materials.
This research work is part of this general framework and aims to develop an innovative smart material, consisting of a mix of cement, aggregates sand and PCM. It is precisely the PCMs integrated into the mix that allow improving its thermal performance and, with an increase in performance, it can correspond to a reduction in the quantity of other materials sand and cement , thus allowing the development of a product with high performance and reduced carbon emissions.
A synthetic state of the art is presented in the first part. Then, mechanical and thermal characterization was developed. From the analysis of the mechanical performance, it emerges that the contribution of the PCM reduces the mechanical strength of the compound, as expected and already found in the literature.
In particular, the mechanical tests performed on the prismatic specimens highlight how the strength decreases as the PCM ratio increases. However, both mixes may be considered suitable for masonry structures and may be classified as M5 and M These results are aligned even if different with respect to some scientific literature data. From the analysis of the thermal performance, it emerges that the mix presents good behavior in terms of insulating properties, in good agreement with literature outcomes.
The hot-plate tests underline a light increase of the thermal conductivity in the temperature range where the PCM is completely solid, with respect to the zone where it is found in the liquid state.
In conclusion, considering the mechanical properties of the mixes, it is possible to observe how the mixes are consistent with their employment for masonry construction both as plaster and as bedding mortar for load-bearing walls, opening up interesting research and development scenarios.
On the other hand, considering the thermal properties of the mixes, it is possible to observe good behavior in terms of insulating properties. The results highlight the potential of composite materials in terms of increasing the performance and applicability to the construction sector.
In this sense, the next phases of the research aim at engaging new mixes with different percentages and with the inclusion of recycled materials. Author Contributions: F. Finally, F. They have made the conceptual- ization of the research and have made the critical revision of the paper, contributing to the analysis and discussion of the results. All authors have contributed to the writing, review and editing of the manuscript. All authors have read and agreed to the published version of the manuscript.
Institutional Review Board Statement: Not applicable. Informed Consent Statement: Not applicable. Data Availability Statement: Not applicable. Conflicts of Interest: The authors declare no conflict of interest. References 1. United Nations. European Commission. Accordo di Parigi. Sanson, A. Pomponi, F. Circular economy for the built environment: A research framework.
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