Preliminary study of the pozzolanic activity of dumped mine wastes obtained from the North Bohemian basin in the Czech Republic

Three dumped raw materials, a tuff and two bentonites, obtained from two mining sites at the North Bohemian basin in the Czech Republic, have been studied in order to evaluate them as pozzolanic admixtures in lime mortars for employment in restoration of cultural heritage objects. After thermal activation (800 °C; 5 h), their pozzolanic properties were compared with those of commercial metakaolin. Quantitative phase analysis with the Rietveld method from X-ray powder diffraction patterns, morphological observations, as well as the Frattini and the modified Chapelle tests were performed. In addition, lime mortars, incorporating the fired materials, were prepared and subjected to simultaneous thermal analysis after a 28-day initial curing (20 ± 1 °C; 60 ± 5 % RH). The results showed that all three materials possess pozzolanic activity. However, when employed in lime mortars they did not result in formation of pozzolanic reaction products. Two methods were proposed to improve their reactivity; grinding to obtain finer particle size and removal of quartz content where necessary

H-1 NMR relaxivity of aqueous suspensions of titanium dioxide nanoparticles coated with a gadolinium(III) chelate of a DOTA-monoamide with a phenylphosphonate pendant arm

peer reviewedA new efficient and easy method to anchor Gd(III) chelates onto a TiO2 surface in order to prepare a nanoparticulate T-1 MRI contrast agent is reported. For this purpose, a new ligand, DOTAPP, a DOTA-monoamide derivative containing a phenylphosphonic acid function in the amide side chain, was synthesized. As expected, its Ln(III) complexes exhibit structure analogy to the Ln(III) complexes of DOTA with one water molecule bound in the apical position. The Gd(III)-DOTAPP complex shows similar relaxometric properties as Gd(III) complexes of other DOTA-monoamides. Gd(III)-DOTAPP was anchored onto the surface of nanocrystalline TiO2 via its phosphonate moiety. The oxide surface is completely covered by the complexes and a strong interaction between the TiO2 surface and the phosphonate group results in stable chemisorption. The millimolar relaxivity (r(1)) of the Gd(III)DOTAPP complex adsorbed on the surface is substantially higher than that of the free (non-anchored) complex

Flood Fatalities in Europe, 1980-2018: Variability, Features, and Lessons to Learn

Floods are still a significant threat to people, despite of the considerable developments in forecasting, management, defensive, and rescue works. In the near future, climate and societal changes as both urbanization of flood prone areas and individual dangerous behaviors could increase flood fatalities. This paper analyzes flood mortality in eight countries using a 39-year database (1980-2018) named EUFF (EUropean Flood Fatalities), which was built using documentary sources. The narratives of fatalities were investigated and standardized in the database reporting the details of the events. The entire dataset shows a stable trend on flood fatalities, despite the existence of individual increasing (Greece, Italy, and South France) and decreasing (Turkey and Catalonia) trends. The 2466 fatalities were mainly males, aged between 30-49 years and the majority of them happened outdoor. Most often people were dragged by water/mud when travelling by motor vehicles. Some cases of hazardous behaviors, such as fording rivers, were also detected. The primary cause of death was drowning, followed by heart attack. This work contributes to understand the human-flood interaction that caused fatalities. The changes in society's vulnerability highlighted throughout this study contribute to manage future risks, to improve people protection actions, and to reduce risk behaviors

Hydrogel Microrobots Self‐Assembled into Ordered Structures with Programmable Actuation

Sub-millimeter robots—microrobots—that can autonomously perform mechanical work at the microscale would radically change new areas of human activity such as micromanipulation, microfabrication, or healthcare. Sets of identical microrobots that can connect into different, larger structures open the possibility for a “universal” microrobotic unit that fulfills a large variety of functions derived from the structure that multiple units can be assembled into. The capability of individual hydrogel microcrawlers to self-assemble under confinement into periodically ordered planar structures is demonstrated. Subsequently, these can be bound together using light to form a solid porous sheet. The lateral shape of the sheet is imprinted during the binding process. Furthermore, the sheets bend into 3D structures, where the bending direction can be programmed. The resulting structures actuate anisotropically when exposed to heat or laser illumination and can be designed for various modes of operation, such as manipulation or untethered locomotion. The formation of ordered microstructures from individual mobile robots enables easier transport and remote assembly of these structures at the place of interest without the need for direct intervention

‘Can I be a kinky ace?’: How asexual people negotiate their experiences of kinks and fetishes

Prior research has found that asexual people may fantasise or participate in activities typically conceptualised as ‘sexual’. These behaviours may be considered paradoxical when an asexual person is conceptualised as someone who does not experience sexual attraction or desire. This research aimed to explore how kinks and fetishes are conceptualised, experienced, and negotiated by asexual individuals. Forty-eight participants were recruited to take part in an online qualitative survey. Thematic analysis resulted in three themes. In “Am I asexual?”: (How) can you be a kinky ace?, we discuss the sense of dissonance which some participants reported in negotiating what was seemingly the paradox between their self-identity as asexual and their exploration of kinks and fetishes. In the second theme, Between me and me’ and make believe: Kinks and fetishes as solo and imaginary, we report on how kinks, fetishes, and fantasies were often understood in a solitary context and as either undesirable – or impossible – to live out. In the final theme, Kink as a sensual enhancement in relationships, we highlight how participants positioned kinks and fetishes as an agent for intimacy. These findings expand our knowledge of how asexual people negotiate kinks and fetishes and capture the complexities of asexual identities

A New Living Emulsion Polymerization Mechanism: Episulfide Anionic Polymerization

The anionic ring-opening polymn. of episulfides has been successfully applied in emulsion. The polymn. proceeded with a living mechanism but was characterized by a limiting conversion, presumably arising from the increase in viscosity in the polymer. To the knowledge of the authors, only two other cases of living anionic polymn. in emulsion are known (silicones and cyanoacrylates); the addnl. novelty presented by episulfides is the ease of end-functionalization. Furthermore, the emulsion polymn. allowed the prepn. of highly stable particles, which, due to their PEGylated surface and their appropriate diam., can be applied in the biomedical field as nanocarriers. [on SciFinder (R)

A new living emulsion polymerization mechanism: Episulfide anionic polymerization

The anionic ring-opening polymerization of episulfides has been successfully applied in emulsion. The polymerization proceeded with a living mechanism but was characterized by a limiting conversion, presumably arising from the increase in viscosity in the polymer. To the knowledge of the authors, only two other cases of living anionic polymerization in emulsion are known (silicones and cyanoacrylates); the additional novelty presented by episulfides is the ease of end-functionalization. Furthermore, the emulsion polymerization allowed the preparation of highly stable particles, which, due to their PEGylated surface and their appropriate diameter, can be applied in the biomedical field as nanocarriers