Photoluminescent color conversion by quantum dots (QDs) makes possible the formation of spectrum-ondemand light sources by combining blue LEDs with the light generated by a specific blend of QDs. Such applications, however, require a near-unity photoluminescence quantum efficiency since self-absorption magnifies disproportionally the impact of photon losses on the overall conversion efficiency. Here, we present a synthesis protocol for forming InP-based QDs with +90% quantum efficiency across the full visible spectrum from blue/cyan to red. The central features of our approach are as follows: (1) the formation of InP core QDs through one-batch-one-size reactions based on aminophosphine as the phosphorus precursor, (2) the introduction of a core/ shell/shell InP/Zn(Se,S)/ZnS structure, and (3) the use of specific interfacial treatments, most notably the saturation of the ZnSe surface with zinc acetate prior to ZnS shell growth. Moreover, we adapted the composition of the Zn(Se,S) inner shell to attain the intended emission color while minimizing line broadening induced by the InP/ZnS lattice mismatch. The protocol is established by analysis of the QD composition and structure using multiple techniques, including solid-state nuclear magnetic resonance spectroscopy and Raman spectroscopy, and verified for reproducibility by having different researchers execute the same protocol. The realization of full-spectrum, +90% quantum efficiency will strongly facilitate research into light−matter interaction in general and luminescent color conversion in particular through InP-based QDs.

The assessment of existing reinforced concrete structures is one of the major aspects for engineers and practitioners. In particular, existing infrastructures, as bridges and viaducts, are extensively exposed to environmental actions, materials aging, degradation, and variation of magnitude of traffic loads during their service life. Hence, the assessment of existing structural systems assuming the same criteria conceived for the design (i.e., partial factor method—EN 1990) can be too conservative and, sometimes, may lead to unnecessary and expensive structural interventions. In this context, fib Bulletin 80 defines the partial factor methods suitable for the assessment of existing reinforced concrete structures accounting for their residual service life, information from in situ and laboratory tests, measurements of variable actions and reduced target reliability levels according to both economical and human safety criteria. The methodologies proposed in fib Bulletin 80 have been applied to assess the safety of an existing prestressed reinforced concrete bridge built in 90s and located in Italy. The results are compared to the outcomes from the assessment performed according to EN1990 and, finally, limits and advantages of the methodologies proposed by fib Bulletin 80 are discussed.

The present study aims to characterize the epistemic uncertainty within the use of global non-linear numerical analyses (i.e., NLNAs) for design and assessment purposes of slender reinforced concrete (RC) members. The epistemic uncertainty associated to NLNAs may be represented by approximations and choices performed during the definition of a structural numerical model.In order to quantify epistemic uncertainty associated to a non-linear numerical simulation, the resistance model uncertainty random variable has to be characterized by means of the comparison between experimental and numerical results. With this aim, a set of experimental tests on slender RC columns known from the literature is considered. Then, the experimental results in terms of maximum axial load are compared to the outcomes achieved from NLNAs. Nine different modeling hypotheses are herein considered to characterize the resistance model uncertainty random variable. The probabilistic analysis of the results has been performed according to Bayesian approach accounting also for both the previous knowledge from the scientific literature and the influence of the experimental uncertainty on the estimation of the statistics of the resistance model uncertainty random variable. Finally, the resistance model uncertainty partial safety factor is evaluated in line with the global resistance format of fib Model Code for Concrete Structures 2010 with reference to new and existing RC structures.

Deterioration process due to corrosion of steel in concrete affects the performance of reinforced concrete structures both in service and ultimate conditions. Corrosion reduces the rebar section, deteriorates the surrounding concrete with the oxides expansion product and it also alters bond between steel and concrete. Moreover, in structures subjected to cyclic loading, the damage due to corrosion can be combined with the mechanical action that is present in service. In this case the initial crack pattern due to load action and to the rheological phenomena is further modified by the expansion of the oxides and by the interaction among those causes. In the present work, the results of an experimental campaign on reinforced concrete elements subjected to simultaneous corrosion and cyclic loading are shown. It is put in evidence the loss of structural performance, by effect of chemical degradation and mechanical action. The key role of the combined effect of those causes of deterioration is also confirmed by static tests performed under the condition of static loading and simultaneous corrosion.