8,144 research outputs found
The Kindergarten Rule of Sustainable Growth
The relationship between economic growth and the environment is not well understood: we have only limited understanding of the basic science involved and very limited data. Because of these difficulties it is especially important to develop a series of relatively simple theoretical models that generate stark predictions. This paper presents one such model where societies implement the Kindergarten rule of sustainable growth.' Following the Kindergarten rule means implementing zero emission technologies in either finite time or asymptotically. The underlying simplicity of the model allows us to provide new predictions linking the path of environmental quality to pollutant characteristics (stocks vs. flows; toxics vs. irritants) and primitives of the economic system. It also provides a novel Environmental Catch-up Hypothesis.
Economic Growth and the Environment: A Review of Theory and Empirics
This paper reviews both theory and empirical work on economic growth and the environment. We develop four simple growth models to help us identify key features generating sustainable growth. We show how some combination of technological progress in abatement, intensified abatement, shifts in the composition of national output and induced innovation are necessary for sustainable growth, and then demonstrate how growth models employing any one of these mechanisms generate other potentially refutable predictions on abatement costs, pollution levels, or emission intensities.
Oblique hypervelocity impact response of dual-sheet structures
The results of a continuing investigation of the phenomena associated with the oblique hypervelocity impact of spherical projectiles onto multi-sheet aluminum structures are given. A series of equations that quantitatively describes these phenomena is obtained through a regression of experimental data. These equations characterize observed ricochet and penetration damage phenomena in a multi-sheet structure as functions of geometric parameters of the structure and the diameter, obliquity, and velocity of the impacting projectile. Crater damage observed on the ricochet witness plates is used to determine the sizes and speeds of the ricochet debris particles that caused the damage. It is observed that the diameter of the most damaging ricochet debris particle can be as large as 40 percent of the original particle diameter and can travel at speeds between 24 percent and 36 percent of the original projectile impact velocity. The equations necessary for the design of shielding panels that will protect external systems from such ricochet debris damage are also developed. The dimensions of these shielding panels are shown to be strongly dependent on their inclination and on their circumferential distribution around the spacecraft
Zero temperature black holes in semiclassical gravity
The semiclassical Einstein equations are solved to first order in for the case of an extreme or nearly extreme Reissner-Nordstr\"{o}m
black hole perturbed by the vacuum stress-energy of quantized free fields. It
is shown that, for realistic fields of spin 0, 1/2, or 1, any zero temperature
black hole solution to the equations must have an event horizon at ,
with the charge of the black hole. It is further shown that no black hole
solutions with can be obtained by solving the semiclassical
Einstein equations perturbatively.Comment: 7 pages, to appear in the Proceedings of the Ninth Marcel Grossmann
Meeting, change in titl
Line plotting program using DI-3000/Grafmaker routines
A line plotting program has been developed using the DI-3000 graphics libraries and incorporates Grafmaker subroutines. The program allows multiple lines on a frame and multiple frames per run. Options such as automatic scaling, linear or single-cycle log graphs, and plot text such as titles, legends and axis labels are incorporated in the program. Greek and other fonts can be used in the plot text as well as upper and lower case text. Plot inputs are specified through a control file. The program also allows display of multiple independent data sets on a single graph
MAD: Conservative Mothers and the Political Transformation of the 1970s in Detroit, Michigan
In 1972, a group of thirteen white mothers founded an educational research organization that would become the Mothers Alert Detroit (MAD). Although primarily known for its role in Detroit\u27s anti-busing movement, MAD was involved in a series of local disputes in the Detroit Public Schools. Through its tenure in the 1970s, MAD opposed efforts to desegregate the public schools, implement sex education courses, reform school textbooks, and increase the mill levy to fund the school system.
I argue that the local political activism of MAD was informed by a conservative gender ideology. Mothers comprised the organization’s leadership and rank-and-file. These women were often members of single income-earning households, and considered motherhood their primary duty in society. Their role as symbolic upholders of the family structure added credence to MAD’s critiques of the negative societal changes they saw funding unfolding. In each education dispute, MAD articulated their conservative politics through gendered concerns of child protection, the preservation of the traditional heterosexual family and the maintenance of the local white community
An analysis of penetration and ricochet phenomena in oblique hypervelocity impact
An experimental investigation of phenomena associated with the oblique hypervelocity impact of spherical projectiles on multisheet aluminum structures is described. A model that can be employed in the design of meteoroid and space debris protection systems for space structures is developed. The model consists of equations that relate crater and perforation damage of a multisheet structure to parameters such as projectile size, impact velocity, and trajectory obliquity. The equations are obtained through a regression analysis of oblique hypervelocity impact test data. This data shows that the response of a multisheet structure to oblique impact is significantly different from its response to normal hypervelocity impact. It was found that obliquely incident projectiles produce ricochet debris that can severely damage panels or instrumentation located on the exterior of a space structure. Obliquity effects of high-speed impact must, therefore, be considered in the design of any structure exposed to the meteoroid and space debris environment
What does a binary black hole merger look like?
We present a method of calculating the strong-field gravitational lensing
caused by many analytic and numerical spacetimes. We use this procedure to
calculate the distortion caused by isolated black holes and by numerically
evolved black hole binaries. We produce both demonstrative images illustrating
details of the spatial distortion and realistic images of collections of stars
taking both lensing amplification and redshift into account. On large scales
the lensing from inspiraling binaries resembles that of single black holes, but
on small scales the resulting images show complex and in some cases
self-similar structure across different angular scales.Comment: 10 pages, 12 figures. Supplementary images and movies can be found at
http://www.black-holes.org/the-science-numerical-relativity/numerical-relativity/gravitational-lensin
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