400 research outputs found
ENVIRONMENTAL LAWâCERCLA ENFORCEMENT: TERMINOLOGY AND MEANING OF âTREATMENTâ ARRANGER LIABILITY
CERCLA arranger liability was forever changed by the Supreme Court decision in Burlington Northern & Santa Fe Ry. Co. v. United States, 556 U.S. 599 (2009). In the aftermath, EPA has been hamstrung with the difficulty of substantiating a Potentially Responsible Partyâs (âPRPâ) intent to arrange for disposal of a hazardous substance, as well as attempting to overcome the ever-increasing scientific capabilities of PRPs to demonstrate that proportionality of damages is appropriate for a given Superfund site. This Article is the first in depth analysis teasing apart what it means for a PRP to arrange for disposal, as opposed to arrange for treatmentâboth found under CERCLA § 107(a)(3)âand to establish that the use of the treatment terminology could strengthen the Environmental Protection Agencyâs (âEPAâ) enforcement efficiency and effectiveness.
In particular, this Article opines on the following: (1) Congress included the treatment term because the treatment of hazardous substances inherently generate the possibility of Superfund sites; (2) Congress intended liability to attach to the transferor anytime the selling party intendsâwhether implicitly or explicitlyâto alter the hazardous substance through some process to make it more useful or reuseable, and that process was the proximate cause of the release of hazardous waste at the site; and (3) attaching liability under the treatment term is an easier standard to meet and would result in an increased percentage of successful CERCLA enforcement actions and contribution claims. To illustrate, this Article discusses two real-world scenarios in an effort to shed light on situations in which treatment arranger liability could and should be utilized as a litigation tactic over disposal arranger liability
Synthesis of perfluorinated polyethers
A series of highly fluorinated acetylenes was prepared and their cyclization reactions were studied. A series of perfluoropolytriazines with -CF2I pendent groups were prepared. These materials can be cured thermally or photochemically to an elastomeric gum. Perfluoropolytriazines with -CN pendent groups were prepared. These materials can be crosslinked by reaction with terephthalonitrile oxide
full-FORCE: A Target-Based Method for Training Recurrent Networks
Trained recurrent networks are powerful tools for modeling dynamic neural
computations. We present a target-based method for modifying the full
connectivity matrix of a recurrent network to train it to perform tasks
involving temporally complex input/output transformations. The method
introduces a second network during training to provide suitable "target"
dynamics useful for performing the task. Because it exploits the full recurrent
connectivity, the method produces networks that perform tasks with fewer
neurons and greater noise robustness than traditional least-squares (FORCE)
approaches. In addition, we show how introducing additional input signals into
the target-generating network, which act as task hints, greatly extends the
range of tasks that can be learned and provides control over the complexity and
nature of the dynamics of the trained, task-performing network.Comment: 20 pages, 8 figure
Affordability Engineering: Bridging the Gap Between Design and Cost
Affordability is a commonly used term that takes on numerous meanings depending on the context used. Within conceptual design of complex systems, the term generally implies comparisons between expected costs and expected resources. This characterization is largely correct, but does not convey the many nuances and considerations that are frequently misunderstood and underappreciated. In the most fundamental sense, affordability and cost directly relate to engineering and programmatic decisions made throughout development programs. Systems engineering texts point out that there is a temporal aspect to this relationship, for decisions made earlier in a program dictate design implications much more so than those made during latter phases. This paper explores affordability engineering and its many sub-disciplines by discussing how it can be considered an additional engineering discipline to be balanced throughout the systems engineering and systems analysis processes. Example methods of multidisciplinary design analysis with affordability as a key driver will be discussed, as will example methods of data visualization, probabilistic analysis, and other ways of relating design decisions to affordability results
Outer jet X-ray and radio emission in R Aquarii: 1999.8 to 2004.0
Chandra and VLA observations of the symbiotic star R Aqr in 2004 reveal
significant changes over the three to four year interval between these
observations and previous observations taken with the VLA in 1999 and with
Chandra in 2000. This paper reports on the evolution of the outer thermal X-ray
lobe-jets and radio jets. The emission from the outer X-ray lobe-jets lies
farther away from the central binary than the outer radio jets, and comes from
material interpreted as being shock heated to ~10^6 K, a likely result of
collision between high speed material ejected from the central binary and
regions of enhanced gas density. Between 2000 and 2004, the Northeast (NE)
outer X-ray lobe-jet moved out away from the central binary, with an apparent
projected motion of ~580 km s^-1. The Southwest (SW) outer X-ray lobe-jet
almost disappeared between 2000 and 2004, presumably due to adiabatic expansion
and cooling. The NE radio bright spot also moved away from the central binary
between 2000 and 2004, but with a smaller apparent velocity than of the NE
X-ray bright spot. The SW outer lobe-jet was not detected in the radio in
either 1999 or 2004. The density and mass of the X-ray emitting material is
estimated. Cooling times, shock speeds, pressure and confinement are discussed.Comment: 23 pages, 8 figure
The Three-Dimensional Expansion of the Ejecta from Tycho's Supernova Remnant
We present the first three-dimensional measurements of the velocity of
various ejecta knots in Tycho's supernova remnant, known to result from a Type
Ia explosion. Chandra X-ray observations over a 12-year baseline from 2003 to
2015 allow us to measure the proper motion of nearly 60 "tufts" of Si-rich
ejecta, giving us the velocity in the plane of the sky. For the line of sight
velocity, we use two different methods: a non-equilibrium ionization model fit
to the strong Si and S lines in the 1.2-2.8 keV regime, and a fit consisting of
a series of Gaussian lines. These methods give consistent results, allowing us
to determine the red or blue shift of each of the knots. Assuming a distance of
3.5 kpc, we find total velocities that range from 2400 to 6600 km s,
with a mean of 4430 km s. We find several regions where the ejecta knots
have overtaken the forward shock. These regions have proper motions in excess
of 6000 km s. Some Type Ia supernova explosion models predict a velocity
asymmetry in the ejecta. We find no such velocity asymmetries in Tycho, and
discuss our findings in light of various explosion models, favoring those
delayed detonation models with relatively vigorous and symmetrical
deflagrations. Finally, we compare measurements with models of the remnant's
evolution that include both smooth and clumpy ejecta profiles, finding that
both ejecta profiles can be accommodated by the observations.Comment: Accepted for publication in ApJ. Some figures slightly degraded to
reduce file siz
Urban envelopes : an architecture of adjacency and difference
Thesis (M. Arch.)--Massachusetts Institute of Technology, Dept. of Architecture, 2008.Includes bibliographical references (p. 148-150).In a contemporary world of rapidly dwindling resources and the sprawling consumption of landscape, it is important to look at the role of boundary, spatial differentiation and the value of spatial diversity while recognizing that the city, like nature, is composed of interdependent parts. Rather than figures apart and a value of transparency over opacity, the perpetual negotiation of figure and ground while maintaining necessary distinctions is of the utmost importance - establishing an order of separation without division. By delineating boundaries, human responsibility can establish and hold its place in the animated, complex and constantly changing nature of the city. The texture of this negotiation at the building envelope reinforces ideas of self while negotiating relationships with others. As the shared boundary of architectural and urban space, the interconnectedness, thickness and representation of envelopes suggest new types of textures and figures as well as a critical, infrastructural, role for architecture in the city. By establishing a link in the loops of operation at the scale of the wall, building type and block topology, this thesis formulates an analytical methodology that avoids both the scenographic, hierarchical and function based idea of traditional space and the universal and detachedness of modern space. Instead, through a critical and design-oriented re-interpretation of the existing non-site condition at New York University, space can be constructed to mediate between itself and surrounding Greenwich Village and SoHo. This implies the need to reconsider programmatically the role of real estate and commercialization in preserving their institution and infrastructure - and the materials of these transitions/mediations. In articulating the line between architectural and urban space and between complimentary and contradictory programs, NYU can articulate its own significance on a cultural and architectural level to make a civic project.by Peter J. DePasquale.M.Arch
Perfluorooctanoic acid exposure assessment on common carp liver through image and ultrastructural investigation
Perfluorooctanoic acid (PFOA) poses particular concern as an emerging pollutant in both surface and ground waters. Fish, as a natural inhabitant of these waters and being highly representative of vertebrates, represents an ideal animal model to assess the toxic effects of PFOA. Hereby, liver microscopic texture was comparatively evaluated in individuals of common carp subchronically exposed to PFOA using grayscale differential box counting, a fractal analysis method. Furthermore, liver cytoplasmic glycogen areas and ultrastructure were also evaluated and compared to the image analysis findings. Redundancy Analysis was performed to assess, in summary, how much the variation of fractal dimension and lacunarity was explained by the concentration of PFOA in liver, the mass of liver and the number of proliferating cell nuclear antigen (PCNA)-immunoreactive nuclei. Treatment group ordination was better determined by fractal dimension than lacunarity. Interestingly, a significant complexity increase was associated with the modification of liver microscopic texture due to PFOA exposure. This complexity increase was related to âcloudy swellingâ, possibly representing a primarily adaptive strategy against PFOA challenge, rather than a slight, reversible form of degeneration as traditionally proposed. The occurrence of endoplasmic reticulum stress, unfolded protein reaction and hormetic response was proposed and discussed
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