57,085 research outputs found
Who Manages The Money? How Foundations Should Help Democratize Capital
For the past twenty-five years or more there has been a groundswell of activity among investment managers institutional investors, consultants and diversity advocates to democratize capital -- that is, to create more opportunities for diverse investment professionals and the firms they lead, to manage institutional capital This effort, grounded in both fiduciary and equity principles, has led to the growth of many diverse investment management firms like Progress Investment Management Company LLC ("Progress") and others. A range of stakeholders now recognizes that democratization of capital brings a range of positive benefits to our industry and society at larg
Nanoscale Charge Balancing Mechanism in Alkali Substituted Calcium-Silicate-Hydrate Gels
Alkali-activated materials and related alternative cementitious systems are
sustainable material technologies that have the potential to substantially
lower CO emissions associated with the construction industry. However, the
impact of augmenting the chemical composition of the material on the main
binder phase, calcium-silicate-hydrate gel, is far from understood,
particularly since this binder phase is disordered at the nanoscale. Here, we
reveal the presence of a charge balancing mechanism at the molecular level,
which leads to stable structures when alkalis (i.e., Na or K) are incorporated
into a calcium-silicate-hydrate gel, as modeled using crystalline 14{\AA}
tobermorite. These alkali containing charge balanced structures possess
superior mechanical properties compared to their charge unbalanced
counterparts. Our results, which are based on first-principles simulations
using density functional theory, include the impact of charge balancing on the
optimized geometries of the new model phases, formation energies, local bonding
environments, bulk moduli and diffusion barriers of the alkali atoms within the
crystals
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High resolution CO observations of S88-B
CO J = 2-1 and 13CO J = 2-1 and 1-0 observations have been made of the H II region S88-B, using the 15-m James Clerk Maxwell telescope in Hawaii and the 20-m telescope at Onsala. The core of the cloud is resolved into a horseshoelike structure which surrounds a diffuse reflection nebula. The central core has a mass of ≥ 1000 M⊙, with 400 M⊙ in the horseshoe structure. The gas in the horse in the horseshoe appears highly fragmented, and has a kinetic temperature of ≈ 60 K, suggesting it is closely coupled to the dust temperature. A recently formed high mass star appears to be in the process of evacuating a cavity, possibly through a large molecular outflow that is found to show an accelerated component in its blue-shifted lobe. A velocity gradient across the horseshoe structure suggest ordered motion, and could represent rotation in the parental cloud
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High signal/noise <sup>13</sup>CO observations of the bipolar outflow in L1551
New high-signal/noise 13CO observations of the bipolar outflow in the molecular cloud L1551 are reported. Contrary to earlier observations of CO J = 1-0 and 2-1, no strong spatial dependence is found for the velocity profile of these spectra. The implications of these observations are such that the model of an empty shell for this source is less likely, and a model consisting of a shell which contains significant amounts of outflowing molecular gas inside the swept-up cavity walls is suggested
Towards a Molecular Inventory of Protostellar Discs
The chemical environment in circumstellar discs is a unique diagnostic of the
thermal, physical and chemical environment. In this paper we examine the
structure of star formation regions giving rise to low mass stars, and the
chemical environment inside them, and the circumstellar discs around the
developing stars.Comment: 9 page PDF, 550 kbyte
A mathematical model for predicting cyclic voltammograms of electronically conductive polypyrrole
Polypyrrole is an attractive polymer for use as a high-energy-density secondary battery because of its potential as an inexpensive, lightweight, and noncorrosive electrode material. A mathematical model to simulate cyclic voltammograms for polypyrrole is presented. The model is for a conductive porous electrode film on a rotating disk electrode (RDE) and is used to predict the spatial and time dependence of concentration, overpotential, and stored charge profiles within a polypyrrole film. The model includes both faradic and capacitance charge components in the total current density expression
Lagrangian Pairs and Lagrangian Orthogonal Matroids
Represented Coxeter matroids of types and , that is, symplectic
and orthogonal matroids arising from totally isotropic subspaces of symplectic
or (even-dimensional) orthogonal spaces, may also be represented in buildings
of type and , respectively. Indeed, the particular buildings
involved are those arising from the flags or oriflammes, respectively, of
totally isotropic subspaces. There are also buildings of type arising
from flags of totally isotropic subspaces in odd-dimensional orthogonal space.
Coxeter matroids of type are the same as those of type (since they
depend only upon the reflection group, not the root system). However, buildings
of type are distinct from those of the other types. The matroids
representable in odd dimensional orthogonal space (and therefore in the
building of type ) turn out to be a special case of symplectic (flag)
matroids, those whose top component, or Lagrangian matroid, is a union of two
Lagrangian orthogonal matroids. These two matroids are called a Lagrangian
pair, and they are the combinatorial manifestation of the ``fork'' at the top
of an oriflamme (or of the fork at the end of the Coxeter diagram of ).
Here we give a number of equivalent characterizations of Lagrangian pairs,
and prove some rather strong properties of them.Comment: Requires amssymb.sty; 12 pages, 2 LaTeX figure
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