Carbon dioxide dissolution in structural and stratigraphic traps

The geologic sequestration of carbon dioxide (CO[subscript 2]) in structural and stratigraphic traps is a viable option to reduce anthropogenic emissions. While dissolution of the CO[subscript 2] stored in these traps reduces the long-term leakage risk, the dissolution process remains poorly understood in systems that reflect the appropriate subsurface geometry. Here, we study dissolution in a porous layer that exhibits a feature relevant for CO[subscript 2] storage in structural and stratigraphic traps: a finite CO[subscript 2] source along the top boundary that extends only part way into the layer. This feature represents the finite extent of the interface between free-phase CO[subscript 2] pooled in a trap and the underlying brine. Using theory and simulations, we describe the dissolution mechanisms in this system for a wide range of times and Rayleigh numbers, and classify the behaviour into seven regimes. For each regime, we quantify the dissolution flux numerically and model it analytically, with the goal of providing simple expressions to estimate the dissolution rate in real systems. We find that, at late times, the dissolution flux decreases relative to early times as the flow of unsaturated water to the CO[subscript 2] source becomes constrained by a lateral exchange flow though the reservoir. Application of the models to several representative reservoirs indicates that dissolution is strongly affected by the reservoir properties; however, we find that reservoirs with high permeabilities (k ≥ 1 Darcy) that are tens of metres thick and several kilometres wide could potentially dissolve hundreds of megatons of CO[subscript 2] in tens of years.United States. Dept. of Energy (Grant DE-SC0003907)United States. Dept. of Energy (Grant DE-FE0002041)MIT Masdar ProgramMartin Family Fellowship for Sustainabilit

Magnetoresistance through a single molecule

The use of single molecules to design electronic devices is an extremely challenging and fundamentally different approach to further downsizing electronic circuits. Two-terminal molecular devices such as diodes were first predicted [1] and, more recently, measured experimentally [2]. The addition of a gate then enabled the study of molecular transistors [3-5]. In general terms, in order to increase data processing capabilities, one may not only consider the electron's charge but also its spin [6,7]. This concept has been pioneered in giant magnetoresistance (GMR) junctions that consist of thin metallic films [8,9]. Spin transport across molecules, i.e. Molecular Spintronics remains, however, a challenging endeavor. As an important first step in this field, we have performed an experimental and theoretical study on spin transport across a molecular GMR junction consisting of two ferromagnetic electrodes bridged by a single hydrogen phthalocyanine (H2Pc) molecule. We observe that even though H2Pc in itself is nonmagnetic, incorporating it into a molecular junction can enhance the magnetoresistance by one order of magnitude to 52%.Comment: To appear in Nature Nanotechnology. Present version is the first submission to Nature Nanotechnology, from May 18th, 201

An analysis of floatability and stability of an inland water rescue vehicle for conducting the rescue activities on the inland waters covered by ice

W artykule przedstawiono wyzwania związane z zastosowaniem małego pojazdu ratownictwa wodnego do prowadzenia akcji na akwenach śródlądowych i wodach przybrzeżnych oraz pokrytych lodem. Przedstawiono koncepcję małego pojazdu ratownictwa wodnego. Opisano wybrane elementy modelowania pływalności i stateczności pojazdu. Przedstawiono podstawowe elementy związane z modelowaniem ruchu i oceną zachowania się obiektu w warunkach operacyjnych. Podano wnioski końcowe dotyczące prowadzonych badań.In the paper the basic problems associated with development the concept of an inland water rescue vehicle PRWL which is devoted to perform the rescue activities on the inland waters covered by ice is presented. The research objective, PRWL vehicle, research method and some elements of the research directed towards development of the PRWL vehicle technology demonstrator has been described. Some elements asso-ciated with assessment of the vehicle floatability, stability and performance in the water have been presented. Some information on a possible application of the PRWL vehicle have been given. The information presented in the paper are the results of work of the authors and results of research investigations conducted at the Gdańsk University of Technology, Faculty of Ocean Engineering and Ship Technology between 2014 and 2015

Increasing Diversity, Equity, and Inclusion in the Soil and Agronomic Sciences through K-12 Outreach and Education

The SSSA K-12 Education and Outreach committee continually organizes and carries out activities, webinars, and workshops geared toward increasing K-12 student interest and participation in soil and agronomic sciences. This presentation highlights the efforts and impact of several committee members in conducting outreach work in their local communities targeted at improving recruitment, retention, and representation of historically marginalized groups- including young women, people of color, and underprivileged youth- in the sciences

The lifetime of carbon capture and storage as a climate-change mitigation technology

In carbon capture and storage (CCS), CO[subscript 2] is captured at power plants and then injected underground into reservoirs like deep saline aquifers for long-term storage. While CCS may be critical for the continued use of fossil fuels in a carbon-constrained world, the deployment of CCS has been hindered by uncertainty in geologic storage capacities and sustainable injection rates, which has contributed to the absence of concerted government policy. Here, we clarify the potential of CCS to mitigate emissions in the United States by developing a storage-capacity supply curve that, unlike current large-scale capacity estimates, is derived from the fluid mechanics of CO[subscript 2] injection and trapping and incorporates injection-rate constraints. We show that storage supply is a dynamic quantity that grows with the duration of CCS, and we interpret the lifetime of CCS as the time for which the storage supply curve exceeds the storage demand curve from CO[subscript 2] production. We show that in the United States, if CO[subscript 2] production from power generation continues to rise at recent rates, then CCS can store enough CO[subscript 2] to stabilize emissions at current levels for at least 100 y. This result suggests that the large-scale implementation of CCS is a geologically viable climate-change mitigation option in the United States over the next century.United States. Dept. of Energy (Grant DE-FE0002041)MIT Energy InitiativeReed Research FundMartin Family Society of Fellows for SustainabilityAtlantic Richfield Company (ARCO

Tabulate Corals after the Frasnian/Famennian Crisis: A Unique Fauna from the Holy Cross Mountains, Poland

Famennian tabulate corals were very rare worldwide, and their biodiversity was relatively low. Here we report a unique tabulate fauna from the mid- and late Famennian of the western part of the Holy Cross Mountains (Kowala and Ostrówka), Poland. We describe eight species (four of them new, namely ?Michelinia vinni sp. nov., Thamnoptychia mistiaeni sp. nov., Syringopora kowalensis sp. nov. and Syringopora hilarowiczi sp. nov.); the whole fauna consists of ten species (two others described in previous papers). These corals form two assemblages-the lower, mid-Famennian with Thamnoptychia and the upper, late Famennian with representatives of genera ?Michelinia, Favosites, Syringopora and ?Yavorskia. The Famennian tabulates from Kowala represent the richest Famennian assemblage appearing after the F/F crisis (these faunas appear some 10 Ma after the extinction event). Corals described here most probably inhabited deeper water settings, near the limit between euphotic and disphotic zones or slightly above. At generic level, these faunas show similarities to other Devonian and Carboniferous faunas, which might suggest their ancestry to at least several Carboniferous lineages. Tabulate faunas described here represent new recruits (the basin of the Holy Cross mountains was not a refuge during the F/F crisis) and have no direct evolutionary linkage to Frasnian faunas from Kowala. The colonization of the seafloor took place in two separate steps: first was monospecific assemblage of Thamnoptychia, and later came the diversified Favosites-Syringopora-Michelinia fauna

Adherence and invasion of Bacteroidales isolated from the human intestinal tract

Members of the genera Bacteroides and Parabacteroides are important constituents of both human and animal intestinal microbiota, and are significant facultative pathogens. In this study, the ability of Bacteroides spp. and Parabacteroides distasonis isolated from both diarrhoeal and normal stools (n = 114) to adhere to and invade HEp-2 cells was evaluated. The presence of putative virulence factors such as capsule and fimbriae was also investigated. Adherence to HEp-2 cells was observed in 75.4% of the strains, which displayed non-localized clusters. Invasion was observed in 37.5% and 26% of the strains isolated from diarrhoeal and non-diarrhoeal stools, respectively. All strains displayed a capsule, whereas none of them showed fimbriae-like structures. This is the first report of the ability of Bacteroides spp. and P. distasonis to adhere to and invade cultured HEp-2 epithelial cells.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)[02/02680-4]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP