Evaluation of an experimental protective coating for bridge steel (88-03)

This report describes the application of an experimental metal sealer to bridge beams which are coated with lead-based paint. Regulations developed by the Environmental Protection Agency (EPA) , prohibit the introduction of material containing lead into the environment. Containment and disposal methods required for sandblasting lead-based paints have proven to be costly. The Oklahoma Department of Transportation is searching for an economic alternative to sandblasting steel. Two bridges in western Oklahoma were treated with the experimental metal sealer in 1962. A visual survey was conducted on these bridges to evaluate the performance of the sealer. However, the formulation of the sealer applied to these bridges is unknown. The experimental sealer required that only dirt, grease, and hard scale be removed prior to application. The sealer was thin and had a tendency to run, even when applied at the manufacturer's suggested rate. The cost of the sealer application was less than removal and containment methods previously used.Construction ReportN

Memory control ability modulates intrusive memories after analogue trauma

AbstractBackgroundMost people suffer from intrusive memories in the aftermath of trauma. For survivors' well-being, it is key that these intrusions are controlled. Memory control can be exerted through retrieval suppression. Poor retrieval suppression, however, should be associated with persistent distressing intrusions and posttraumatic stress disorder (PTSD). This study tested the hypothesis that individual differences in retrieval suppression predict intrusive memories after trauma. Retrieval suppression was examined with the think/no-think task (TNT) using behavioral and event related potential (ERP) measures.MethodsTwenty-four healthy participants watched a “traumatic” film after performing the TNT task. The frequency and distress of intrusions from the “traumatic” film was measured with an electronic diary. Additionally the Impact of Event Scale (IES) was assessed.ResultsIn line with our hypothesis, behavioral measures of retrieval suppression ability predicted reduced distress ratings for intrusions (r=−.53, p<.01). Further ERP markers of retrieval suppression (a fronto-centrally distributed N2) predicted reduced distress ratings for intrusions (r=−.45, p<.05) and reduced IES Intrusion scores (r=−.56, p<.01).LimitationsThe presented film is a relatively mild stressor as compared to a real-life trauma. Further studies are needed to explore the role of memory control processes for real-life trauma.ConclusionsParticipants with lower retrieval suppression ability exhibited less distressing intrusive memories after analogue trauma. The ERP correlate of retrieval suppression was associated with less distressing intrusive memories and reduced IES Intrusion scores, suggesting that deficient memory control is a potential risk factor for developing PTSD

Alkoxy-functionalized ionic liquid electrolytes: Understanding ionic coordination of calcium ion speciation for the rational design of calcium electrolytes

There is growing interest in the rational design of electrolytes for multivalent-ion batteries by tuning the molecular-level interactions of solvate species present in the electrolytes. Herein, we report our effort to control Ca-ion speciation in ionic liquid (IL) based electrolytes through the design of alkoxy-functionalized cations. Quantitative analysis reveals that the alkoxy-functionalized ammonium cation (N$_{07}$$^{+}$), bearing seven ether oxygen atoms, can effectively displace the bis(trifluoromethanesulfonyl)imide anion (TFSI$^{-}$) from the Ca$^{2+}$ ion coordination sphere, facilitating the reversible Ca deposition/stripping process. More importantly, post-analysis of Ca deposits surface chemistry and density functional theory calculations of Ca-ion speciation indicate the formation of an organic-rich, but inorganic-poor solid electrolyte interphase layer, which enables Ca$^{+2}$ ion diffusion rather than passivating the Ca metal electrode. Finally, as a proof-of-concept, a prototype Ca/V$_{2}$O$_{5}$ cell using the optimized IL-based electrolyte ([Ca(BH$_{4}$)$_{2}$]$_{0.05}$ [N$_{07}$TFSI]$_{0.95}$) is demonstrated for the first time, exhibiting a remarkable initial discharge capacity of 332 mA h g$^{-1}$ and reversible capacity of 244 mA h g$^{-1}$

Novel Polyoxometalate- Ionic Liquid with Antibacterial and Antifungal Properties. Feasibility of Its Implementation As a Multifunctional Thin Coating

The synthesis of hybrid materials, combining the properties of organic and inorganic components, results in composites with unique physical and chemical features. Polyoxometalates (POMs), i.e. inorganic anionic molecular metal oxides, are considered as promising future metallodrugs due to their antiviral, antitumoral and antibacterial activities. The combination of bulky organic cations with POMs results in composite ionic liquids (IL; melting point below 100°C) which combine the unique properties of both components. Pioneering studies have used composites of alkylammonium cations and POM anions for multifunctional water purification to remove toxic heavy materials, organic aromatics and microbes and for the inhibition of bio-corrosion on metal and stone surfaces due to coating formation.Fil: Enderle, Ana Gabriela. Universidad Nacional del Litoral; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Streb, C.. Universitat Ulm; AlemaniaFil: Bollini, Mariela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; ArgentinaFil: Culzoni, Maria Julia. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Química. Cátedra de Química Analítica; ArgentinaFil: Mitchell, S. G.. Universidad de Zaragoza; EspañaFil: Franco Castillo, I.. Universidad de Zaragoza; España2019 AIChE Annual MeetingOrlandoEstados UnidosAmerican Institute of Chemical Engineer

Redox-inactive ions control the redox-activity of molecular vanadium oxides

Polyoxometalates are key materials for energy conversion and storage due to their unique chemical tunability and electrochemical reactivity. Herein, we report that functionalization of molecular vanadium oxides, polyoxovanadates, with redox-inert Ca$^{2+}$ cations leads to a significant increase in their electron storage capabilities. The electrochemical performance of the Ca$^{2+}$-functionalized dodecavanadate [Ca$_{2}$V$_{12}$O$_{32}$Cl(DMF) $_{3}$]$^{2-}$ (={Ca$_{2}$V$_{12}$}) was thus compared with that of the precursor compound (H$_{2}$NMe$_{2}$)$_{2}$ [V$_{12}$O$_{32}$Cl] $^{3-}$ (={V$_{12}$}). {Ca$_{2}$V$_{12}$} can store up to five electrons per cluster, while {V12} only shows one reversible redox transition. In initial studies, we demonstrated that {Ca$_{2}$V$_{12}$} can be used as an active material in lithium-ion cathodes. Our results show how redox-inert cations can be used as structural and electrostatic stabilizers, leading to major changes in the redox-chemistry of polyoxovanadates

Evaluating the durability and performance of polyoxometalate-ionic liquid coatings on calcareous stones: Preventing biocolonisation in outdoor environments

Rock-based materials exposed to outdoor environments are naturally colonised by an array of microorganisms, which can cause dissolution and fracturing of the natural stone. Biocolonisation of monuments and architectures of important cultural heritage therefore represents an expensive and recurring problem for local authorities and private owners alike. In this area, preventive strategies to mitigate biocolonisation are generally preferred to curative approaches, such as mechanical cleaning by brush or high-pressure cleaning, to remove pre-existing patina. The aim of this work was to study the interaction between biocidal polyoxometalate-ionic liquid (POM-IL) coatings and calcareous stones and evaluate the capacity of these coatings to prevent biocolonisation through a series of accelerated ageing studies in climate chambers, carried out in parallel with a two-year period of outdoor exposure in north-eastern France. Our experiments show that POM-IL coatings did not affect water vapour transfer nor significantly alter the total porosity of the calcareous stones. Simulated weathering studies replicating harsh (hot and wet) climatic weather conditions demonstrated that the colour variation of POM-IL-coated stones did not vary significantly with respect to the natural uncoated stones. Accelerated biocolonisation studies performed on the weathered POM-IL-coated stones proved that the coatings were still capable of preventing colonisation by an algal biofilm. However, a combination of colour measurements, chlorophyll fluorescence data, and scanning electron microscopy imaging of stones aged outdoors in northern France for two years showed that coated and uncoated stone samples showed signs of colonisation by fungal mycelium and phototrophs. Altogether, our results demonstrate that POM-ILs are suitable as preventative biocidal coatings for calcareous stones, but the correct concentrations must be chosen to achieve a balance between porosity of the stone, the resulting colour variation and the desired duration of the biocidal effect over longer periods of time, particularly in outdoor environments

Catching-up and falling behind knowledge spillover from American to German machine tool makers

In our days, German machine tool makers accuse their Chinese competitors of violating patent rights and illegally imitating German technology. A century ago, however, German machine tool makers used exactly the same methods to imitate American technology. To understand the dynamics of this catching-up process we use patent statistics to analyze firms? activities between 1877 and 1932. We show that German machine tool makers successfully deployed imitating and counterfeiting activities in the late 19th century and the 1920s to catchup to their American competitors. The German administration supported this strategy by stipulating a patent law that discriminated against foreign patent holders and probably also by delaying the granting of patents to foreign applicants. Parallel to the growing international competitiveness of German firms, however, the willingness to guarantee intellectual property rights of foreigners was also increasing because German firms had now to fear retaliatory measures in their own export markets when violating foreign property rights within Germany

Multifunctional Polyoxometalate Platforms for Supramolecular Light-Driven Hydrogen Evolution

Multifunctional supramolecular systems are a central research topic in light-driven solar energy conversion. Here, we report a polyoxometalate (POM)-based supramolecular dyad, where two platinum-complex hydrogen evolution catalysts are covalently anchored to an Anderson polyoxomolybdate anion. Supramolecular electrostatic coupling of the system to an iridium photosensitizer enables visible light-driven hydrogen evolution. Combined theory and experiment demonstrate the multifunctionality of the POM, which acts as photosensitizer/catalyst-binding-site[1] and facilitates light-induced charge-transfer and catalytic turnover. Chemical modification of the Pt-catalyst site leads to increased hydrogen evolution reactivity. Mechanistic studies shed light on the role of the individual components and provide a molecular understanding of the interactions which govern stability and reactivity. The system could serve as a blueprint for multifunctional polyoxometalates in energy conversion and storage

New protective coatings against lampenflora growing in the Pommery Champagne cellar

Phototrophic microorganisms such as cyanobacteria and microalgae can proliferate readily in underground heritage sites where the introduction of artificial illumination equipment has significantly altered previously stable environmental conditions. The extended lampenflora biofilm growth on the bas-reliefs carved in the underground Pommery Champagne cellar in Reims (France) represents a recurring biocolonisation problem which requires periodic cleaning. The aim of this work was to limit the growth of lampenflora on chalk substrates using preventative biocidal treatments based on polyoxometalate ionic liquids (POM-ILs). Biocidal assays carried out in laboratory showed how two different colourless POM-IL coatings were more effective than commercial Preventol RI80 against two algal strains isolated from the Pommery bas reliefs, Pseudostichococcus monallantoides and Chromochloris zofingiensis. However, only one POM-IL variant was capable of sustained prevention of biofilm growth when applied to wet chalk, which replicates the more drastic natural environmental conditions of the cellar and can limit the performance of the biocidal coatings. Crucially, coating concentration studies demonstrate how POM-IL-coated slabs from previous experiments retain their biocidal activity and can prevent subsequent recolonisation following the re-inoculation of coated slabs with algae and cyanobacteria. Consequently, POM-ILs represent excellent candidates to eliminate lampenflora growth on the chalk bas-reliefs in the unique subterranean environment of the Pommery Champagne cellar. © 2022 The Author