Pressure buildup during CO2 injection in brine aquifers using the Forchheimer equation

If geo-sequestration of CO2 is to be employed as a key emissions reduction method in the global effort to mitigate climate change, simple yet robust screening of the risks of disposal in brine aquifers will be needed. There has been significant development of simple analytical and semi-analytical techniques to support screening analysis and performance assessment for potential carbon sequestration sites. These techniques have generally been used to estimate the size of CO2 plumes for the purpose of leakage rate estimation. A common assumption has been that both the fluids and the geological formation are incompressible. Consequently, calculation of pressure distribution requires the specification of an arbitrary radius of influence. In this talk, a new similarity solution is derived using the method of matched asymptotic expansions. By allowing for slight compressibility in the fluids and formation, the solution improves on previous work by not requiring the specification of an arbitrary radius of influence. A large-time approximation of the solution is then extended to account for non-Darcy inertial effects using the Forchheimer equation. Both solutions are verified by comparison with finite difference solutions. The results show that inertial losses will often be comparable, and sometimes greater than, the viscous Darcy-like losses associated with the brine displacement, although this is strongly dependent on formation porosity and permeability

Shaped Pupil Lyot Coronagraphs: High-Contrast Solutions for Restricted Focal Planes

Coronagraphs of the apodized pupil and shaped pupil varieties use the Fraunhofer diffraction properties of amplitude masks to create regions of high contrast in the vicinity of a target star. Here we present a hybrid coronagraph architecture in which a binary, hard-edged shaped pupil mask replaces the gray, smooth apodizer of the apodized pupil Lyot coronagraph (APLC). For any contrast and bandwidth goal in this configuration, as long as the prescribed region of contrast is restricted to a finite area in the image, a shaped pupil is the apodizer with the highest transmission. We relate the starlight cancellation mechanism to that of the conventional APLC. We introduce a new class of solutions in which the amplitude profile of the Lyot stop, instead of being fixed as a padded replica of the telescope aperture, is jointly optimized with the apodizer. Finally, we describe shaped pupil Lyot coronagraph (SPLC) designs for the baseline architecture of the Wide-Field Infrared Survey Telescope-Astrophysics Focused Telescope Assets (WFIRST-AFTA) coronagraph. These SPLCs help to enable two scientific objectives of the WFIRST-AFTA mission: (1) broadband spectroscopy to characterize exoplanet atmospheres in reflected starlight and (2) debris disk imaging.Comment: 41 pages, 15 figures; published in the JATIS special section on WFIRST-AFTA coronagraph

The determinants of foreign aid: do socialist welfare states give more foreign aid than others by conditioning public opinion?

Les études menées par Lumsdaine (1993) et Noël et Thérien (1995) montrent que les États-providence socialistes fournissent plus d'aide publique au développement que les autres types d'État-providence. Les États-providence sont généralement considérés comme l'institutionnalisation des valeurs de la justice distributive. Mais en tant qu'institutions, ils sont également sensés transmettre ces valeurs et influencer les dirigeant politiques et l'opinion publique. Cet article met à l'épreuve cette hypothèse grâce à une analyse de régression qui s'appuie sur une nouvelle base de données, indisponible jusqu'à ce jour. Cette analyse remet en question les résultats et le cadre théorique de Lumsdaine et Noël et Thérien.Lumsdaine (1993) and Noël and Thérien (1995) argue that socialist welfare states give more foreign aid than other types of welfare states. Socialist welfare states are seen as institutionalised values of distributive justice. But as institutions, they also said to re-transmit these values and have a conditioning effect on policy makers and public opinion. This paper tests these hypotheses with pooled cross-sectional time-series analysis based on new dataset that was previously unavailable. The analysis in this paper casts doubts over their original findings and theoretical framework

Visualizing Spacetime Curvature via Frame-Drag Vortexes and Tidal Tendexes II. Stationary Black Holes

When one splits spacetime into space plus time, the Weyl curvature tensor (which equals the Riemann tensor in vacuum) splits into two spatial, symmetric, traceless tensors: the tidal field $E$, which produces tidal forces, and the frame-drag field $B$, which produces differential frame dragging. In recent papers, we and colleagues have introduced ways to visualize these two fields: tidal tendex lines (integral curves of the three eigenvector fields of $E$) and their tendicities (eigenvalues of these eigenvector fields); and the corresponding entities for the frame-drag field: frame-drag vortex lines and their vorticities. These entities fully characterize the vacuum Riemann tensor. In this paper, we compute and depict the tendex and vortex lines, and their tendicities and vorticities, outside the horizons of stationary (Schwarzschild and Kerr) black holes; and we introduce and depict the black holes' horizon tendicity and vorticity (the normal-normal components of $E$ and $B$ on the horizon). For Schwarzschild and Kerr black holes, the horizon tendicity is proportional to the horizon's intrinsic scalar curvature, and the horizon vorticity is proportional to an extrinsic scalar curvature. We show that, for horizon-penetrating time slices, all these entities ($E$, $B$, the tendex lines and vortex lines, the lines' tendicities and vorticities, and the horizon tendicities and vorticities) are affected only weakly by changes of slicing and changes of spatial coordinates, within those slicing and coordinate choices that are commonly used for black holes. [Abstract is abbreviated.]Comment: 19 pages, 7 figures, v2: Changed to reflect published version (changes made to color scales in Figs 5, 6, and 7 for consistent conventions). v3: Fixed Ref

The Unionid Mussel Fauna of Northeastern Ohio’s Grand River

Author Institution: Environmental Studies Program, Hiram College, OHAuthor Institution: Dept. of GBES, Cleveland State University, OHAuthor Institution: EnviroScience, Inc., Stow, OHAuthor Institution: Hiram College, OHUnionid mussel distribution, numbers, and species were examined in the Grand River to provide a recent and comprehensive study of mussels from northeast Ohio’s longest river. The entire length of the Grand was canoed and examined for unionid mussel beds, with the exception of upstream areas where the river was small; SCUBA was used to survey just upstream of Fairport Harbor. The lower river, designated Grand River’s Wild and Scenic section, was studied in 1995, the middle reaches, called the Scenic section, were surveyed in 1996, and completion of the headwater region followed in 1998. Finally, a survey near the mouth of the river was made in 2002. A total of 95 sites were examined visually, by hand, with bottom sieves, dip nets, or by diving, as conditions demanded; riverbanks were searched for dead shells. A total of 11,625 living mussels and 4,514 dead shells comprising 27 species were identified. All species found were represented by living specimens. Comparisons to earlier collections indicated that the unionid fauna is changing, especially in downstream areas, but the diversity of these threatened acroinvertebrates in the Grand River has been much less affected than in the neighboring Ohio rivers to the west

The Unionid Mussel Fauna of Northeastern Ohio’s Grand River

Unionid mussel distribution, numbers, and species were examined in the Grand River to provide a recent and comprehensive study of mussels from northeast Ohio’s longest river. The entire length of the Grand was canoed and examined for unionid mussel beds, with the exception of upstream areas where the river was small; SCUBA was used to survey just upstream of Fairport Harbor. The lower river, designated Grand River’s Wild and Scenic section, was studied in 1995, the middle reaches, called the Scenic section, were surveyed in 1996, and completion of the headwater region followed in 1998. Finally, a survey near the mouth of the river was made in 2002. A total of 95 sites were examined visually, by hand, with bottom sieves, dip nets, or by diving, as conditions demanded; riverbanks were searched for dead shells. A total of 11,625 living mussels and 4,514 dead shells comprising 27 species were identified. All species found were represented by living specimens. Comparisons to earlier collections indicated that the unionid fauna is changing, especially in downstream areas, but the diversity of these threatened macroinvertebrates in the Grand River has been much less affected than in the neighboring Ohio rivers to the west

Frame-Dragging Vortexes and Tidal Tendexes Attached to Colliding Black Holes: Visualizing the Curvature of Spacetime

When one splits spacetime into space plus time, the spacetime curvature (Weyl tensor) gets split into an "electric" part E_{jk} that describes tidal gravity and a "magnetic" part B_{jk} that describes differential dragging of inertial frames. We introduce tools for visualizing B_{jk} (frame-drag vortex lines, their vorticity, and vortexes) and E_{jk} (tidal tendex lines, their tendicity, and tendexes), and also visualizations of a black-hole horizon's (scalar) vorticity and tendicity. We use these tools to elucidate the nonlinear dynamics of curved spacetime in merging black-hole binaries.Comment: 4 pages, 5 figure

Families at Five: Extending Land-Grant Research Findings to Families

Families at Five is a joint community outreach partnership between Colorado State University (CSU) Department of Human Development and Family Studies and CSU Cooperative Extension. The program provides research-based family life education and resources to families, Extension educators, and family life community professionals. Comprised of an adult program with accompanying programs for adolescents and children, Families at Five is designed to educate family members on ways to strengthen family relationships. Included in the article are suggestions for engaging Cooperative Extension agents and other community practitioners in the program planning and delivery of educational programs

Visualizing Spacetime Curvature via Frame-Drag Vortexes and Tidal Tendexes III. Quasinormal Pulsations of Schwarzschild and Kerr Black Holes

In recent papers, we and colleagues have introduced a way to visualize the full vacuum Riemann curvature tensor using frame-drag vortex lines and their vorticities, and tidal tendex lines and their tendicities. We have also introduced the concepts of horizon vortexes and tendexes and 3-D vortexes and tendexes (regions where vorticities or tendicities are large). Using these concepts, we discover a number of previously unknown features of quasinormal modes of Schwarzschild and Kerr black holes. These modes can be classified by mode indexes (n,l,m), and parity, which can be electric [(-1)^l] or magnetic [(-1)^(l+1)]. Among our discoveries are these: (i) There is a near duality between modes of the same (n,l,m): a duality in which the tendex and vortex structures of electric-parity modes are interchanged with the vortex and tendex structures (respectively) of magnetic-parity modes. (ii) This near duality is perfect for the modes' complex eigenfrequencies (which are well known to be identical) and perfect on the horizon; it is slightly broken in the equatorial plane of a non-spinning hole, and the breaking becomes greater out of the equatorial plane, and greater as the hole is spun up; but even out of the plane for fast-spinning holes, the duality is surprisingly good. (iii) Electric-parity modes can be regarded as generated by 3-D tendexes that stick radially out of the horizon. As these "longitudinal," near-zone tendexes rotate or oscillate, they generate longitudinal-transverse near-zone vortexes and tendexes, and outgoing and ingoing gravitational waves. The ingoing waves act back on the longitudinal tendexes, driving them to slide off the horizon, which results in decay of the mode's strength. (iv) By duality, magnetic-parity modes are driven in this same manner by longitudinal, near-zone vortexes that stick out of the horizon. [Abstract abridged.]Comment: 53 pages with an overview of major results in the first 11 pages, 26 figures. v2: Very minor changes to reflect published version. v3: Fixed Ref