The Climate Change Landscape – Including What You Can Do (Invited Speaker)

You read about it all the time: The climate is changing. Temperatures are rising, snow and rainfall patterns are shifting, and more extreme climate events – like heavy rainstorms and record high temperatures – are already happening. Many of these observed changes are linked to the rising levels of carbon dioxide and other greenhouse gases in our atmosphere, caused by human activities. Fortunately, individuals, businesses, governments, and other organizations are taking action to address the causes and impacts of climate change. This presentation includes information about the basics of climate change science, what EPA is doing about climate change, and what you can do to help

pp-brane Galilean and Carrollian Geometries and Gravities

We study $D$-dimensional $p$-brane Galilean geometries via the intrinsic torsion of their adapted connections. These non-Lorentzian geometries are examples of $G$-structures whose characteristic tensors consist of two degenerate ``metrics'' of ranks $(p+1)$ and $(D-p-1)$. We carry out the analysis in two different ways. In one way, inspired by Cartan geometry, we analyse in detail the space of intrinsic torsions (technically, the cokernel of a Spencer differential) as a representation of $G$, exhibiting for generic $(p,D)$ five classes of such geometries, which we then proceed to interpret geometrically. We show how to re-interpret this classification in terms of ($D-p-2$)-brane Carrollian geometries. The same result is recovered by methods inspired by similar results in the physics literature: namely by studying how far an adapted connection can be determined by the characteristic tensors and by studying which components of the torsion tensor do not depend on the connection. As an application, we derive a gravity theory with underlying $p$-brane Galilean geometry as a non-relativistic limit of Einstein--Hilbert gravity and discuss how it gives a gravitational realisation of some of the intrinsic torsion constraints found in this paper. Our results also have implications for gravity theories with an underlying ($D-p-2$)-brane Carrollian geometry.Comment: 58 pages, 4 figure

p-brane Galilean and Carrollian Geometries and Gravities

We study D-dimensional p-brane Galilean geometries via the intrinsic torsion of the adapted
connections of their degenerate metric structure. These non-Lorentzian geometries are exam-
ples of G-structures whose characteristic tensors consist of two degenerate "metrics" of ranks
(p + 1) and (D − p − 1). We carry out the analysis in two different ways. In one way, in-
spired by Cartan geometry, we analyse in detail the space of intrinsic torsions (technically, the
cokernel of a Spencer differential) as a representation of G, exhibiting for generic (p, D) five
classes of such geometries, which we then proceed to interpret geometrically. We show how to
re-interpret this classification in terms of (D − p − 2)-brane Carrollian geometries. The same
result is recovered by methods inspired by similar results in the physics literature: namely
by studying how far an adapted connection can be determined by the characteristic tensors
and by studying which components of the torsion tensor do not depend on the connection.
As an application, we derive a gravity theory with underlying p-brane Galilean geometry as a
non-relativistic limit of Einstein–Hilbert gravity and discuss how it gives a gravitational real-
isation of some of the intrinsic torsion constraints found in this paper. Our results also have
implications for gravity theories with an underlying (D − p − 2)-brane Carrollian geometry

Characterization of Radiation Fields in Biological Shields of Nuclear Power Plants for Assessing Concrete Degradation*

Life extensions of nuclear power plants to 60 and potentially 80 years of operation have renewed interest in long-term material degradation. One material being considered is concrete, with a particular focus on radiation-induced effects. Based on the projected neutron fluence values (E > 0.1 MeV) in the concrete biological shields of the US pressurized water reactor fleet and the available data on radiation effects on concrete, some decrease in mechanical properties of concrete cannot be ruled out during extended operation beyond 60 years. An expansion of the irradiated concrete database and a reliable determination of relevant neutron fluence energy cutoff value are necessary to ensure reliable risk assessment for extended operation of nuclear power plants

Characterization of Radiation Fields for Assessing Concrete Degradation in Biological Shields of NPPs

Life extensions of nuclear power plants (NPPs) to 60 years of operation and the possibility of subsequent license renewal to 80 years have renewed interest in long-term material degradation in NPPs. Large irreplaceable sections of most nuclear generating stations are constructed from concrete, including safety-related structures such as biological shields and containment buildings; therefore, concrete degradation is being considered with particular focus on radiation-induced effects. Based on the projected neutron fluence values (E > 0.1 MeV) in the concrete biological shields of the US pressurized water reactor fleet and the currently available data on radiation effects on concrete, some decrease in mechanical properties of concrete cannot be ruled out during extended operation beyond 60 years. An expansion of the irradiated concrete database is desirable to ensure reliable risk assessment for extended operation of nuclear power plants

Characterization of Radiation Fields for Assessing Concrete Degradation in Biological Shields of NPPs

Life extensions of nuclear power plants (NPPs) to 60 years of operation and the possibility of subsequent license renewal to 80 years have renewed interest in long-term material degradation in NPPs. Large irreplaceable sections of most nuclear generating stations are constructed from concrete, including safety-related structures such as biological shields and containment buildings; therefore, concrete degradation is being considered with particular focus on radiation-induced effects. Based on the projected neutron fluence values (E > 0.1 MeV) in the concrete biological shields of the US pressurized water reactor fleet and the currently available data on radiation effects on concrete, some decrease in mechanical properties of concrete cannot be ruled out during extended operation beyond 60 years. An expansion of the irradiated concrete database is desirable to ensure reliable risk assessment for extended operation of nuclear power plants

Characterization of Radiation Fields in Biological Shields of Nuclear Power Plants for Assessing Concrete Degradation

Life extensions of nuclear power plants to 60 and potentially 80 years of operation have renewed interest in long-term material degradation. One material being considered is concrete, with a particular focus on radiation-induced effects. Based on the projected neutron fluence values (E > 0.1 MeV) in the concrete biological shields of the US pressurized water reactor fleet and the available data on radiation effects on concrete, some decrease in mechanical properties of concrete cannot be ruled out during extended operation beyond 60 years. An expansion of the irradiated concrete database and a reliable determination of relevant neutron fluence energy cutoff value are necessary to ensure reliable risk assessment for extended operation of nuclear power plants