2,779 research outputs found
State and green crimes related to water pollution and ecological disorganization: water pollution from publicly owned treatment works (POTW) facilities across US states
Green criminologists often refer to water pollution as an example of a green crime, but have yet to produce much research on this subject. The current article addresses the need for green criminological analyses of water pollution problems, and draws attention to an overlooked issue: water pollution emissions from state owned public water treatment facilities or POTWs. Legally, POTWs may emit certain quantities and kinds of pollutants to waterways following treatment. This does not mean, however, that those emissions have no adverse ecological or public health impacts, or that those emissions cannot also be employed as examples of green crimes or green-state crimes. Indeed, from the perspective of environmental sociology and ecological Marxism, those emissions generate ecological disorganization. Moreover, POTW emissions contain numerous pollutants that generate different forms of ecological disorganization. The current study uses POTW emissions data drawn from the US EPAâs Discharge Monitoring Report system for 2014 to illustrate the extent of pollution emitted by POTWs in and across US states as one dimension of ecological disorganization. To contextualize the meaning of those data, we review US water pollution regulations, review the health and ecological impacts of chemicals emitted by POTWs, and situate those emissions within green criminological discussions of green crime and green-state crimes
The Soft Landing Problem: Minimizing Energy Loss by a Legged Robot Impacting Yielding Terrain
Enabling robots to walk and run on yielding terrain is increasingly vital to
endeavors ranging from disaster response to extraterrestrial exploration. While
dynamic legged locomotion on rigid ground is challenging enough, yielding
terrain presents additional challenges such as permanent ground deformation
which dissipates energy. In this paper, we examine the soft landing problem:
given some impact momentum, bring the robot to rest while minimizing foot
penetration depth. To gain insight into properties of penetration
depth-minimizing control policies, we formulate a constrained optimal control
problem and obtain a bang-bang open-loop force profile. Motivated by examples
from biology and recent advances in legged robotics, we also examine
impedance-control solutions to the dimensionless soft landing problem. Through
simulations, we find that optimal impedance reduces penetration depth nearly as
much as the open-loop force profile, while remaining robust to model
uncertainty. Through simulations and experiments, we find that the solution
space is rich, exhibiting qualitatively different relationships between impact
velocity and the optimal impedance for small and large dimensionless impact
velocities. Lastly, we discuss the relevance of this work to
minimum-cost-of-transport locomotion for several actuator design choices
Enhancement of pigmeat quality by altering pre-slaughter management
End of project reportThe studies presented in this report were conducted to investigate the effect of breed, slaughter weight, castration of male pigs and strategic feeding strategies on the performance of pigs to slaughter and on
their carcass quality.
The effect of breed, gender and feeding regimen on the performance of pigs and their carcass quality was examined in the first study (Section 3). From weaning to slaughter Landrace-sired pigs grew at a similar rate but had a better feed conversion efficiency compared with Duroc-sired pigs.
Landrace-sired pigs also had a higher carcass lean and greater muscle depth than Duroc-sired pigs.
Entire male pigs grew more efficiently, had lower lean content in their carcasses and had a reduced kill out yield when compared with gilts. The eye muscle depth was greater for gilts than entire males.
Diluting the diet with grass-meal (GM) reduced growth rate, caused a deterioration in feed conversion efficiency, reduced back fat thickness, reduced eye muscle thickness and reduced kill out yield compared to the control feeding regimen of a cereal based diet. Compensatory growth was observed
during a re-alimentation period following a period of diet dilution with grass-meal. However,
where it did occur, in most cases it was only partial. Adding 5% rapeseed oil instead of lard to the finisher diet increased nitrogen utilization efficiency and phosphorous utilization efficiency.
The effect of gender (boar, castrate, gilt) and slaughter weight (80 to 120kg) on pig performance, carcass quality, meat quality, and nitrogen excretion was investigated in the second study (Section 4).
Boars grew faster than gilts and more efficiently than castrates or gilts. Castrates had a higher kill out
yield than boars. Nitrogen excretion from castrates was similar to gilts which were both higher than that from boars. The processing value of carcasses from castrates may be higher than that of boars and
gilts. In particular castrates had heavier loins and bellies than either boars or gilts. Carcasses from castrates and gilts had a higher temperature (recorded 24 hours post slaughter) than boars. However,
pH24 was not affected by gender. The intramuscular fat content of the l. dorsi in castrates was higher than that of boars or gilts, however at 1.65% this was well below the level (2.0%) above which any
noticeable sensory attributes might be detected.
Feed intake increased with increasing slaughter weight and feed conversion efficiency deteriorated. N
excretion also increased with each increment in weight. Carcass lean content increased up to 90kg live EOP 4939.doc 4 25/10/2005
weight then reached a plateau and declined after 110kg live weight. Heavier carcasses yielded more product for approximately the same slaughtering cost and the associated larger muscles could make it
easier to use seam butchery techniques that result in lean, well-trimmed, attractive cuts and joints. The pH45 and pH24 were reduced with increasing slaughter weight and drip loss increased. Heavier pigs
may be more prone to the development of PSE than lighter pigs as their carcass temperature remains higher for longer than that of lighter pigs
The Treadmill of Production and the Treadmill of Law: Propositions for Analyzing Law, Ecological Disorganization and Crime
Treadmill of production (ToP) arguments have significant implications for the study of environmental crime. A current limitation of those arguments involves their application to environmental law and its enforcement. We argue that a treadmill of law (ToL) shapes and maintains production through lawmaking and enforcement practices, issues that have yet to receive significant attention in the ToP literature. To illustrate the connection between the ToL and ToP and to facilitate political economic analysis of this connection, we make and discuss three propositions. In particular, we suggest that the ToL will (1) oppose the enhancement of environmental regulation through acts of state corporate crime, if necessary; (2) fail to enforce criminal laws in ways that would alter production practices; and (3) define intense opposition to ToP interests and actors as criminal
Efficient, Responsive, and Robust Hopping on Deformable Terrain
Legged robot locomotion is hindered by a mismatch between applications where
legs can outperform wheels or treads, most of which feature deformable
substrates, and existing tools for planning and control, most of which assume
flat, rigid substrates. In this study we focus on the ramifications of plastic
terrain deformation on the hop-to-hop energy dynamics of a spring-legged
monopedal hopping robot animated by a switched-compliance energy injection
controller. From this deliberately simple robot-terrain model, we derive a
hop-to-hop energy return map, and we use physical experiments and simulations
to validate the hop-to-hop energy map for a real robot hopping on a real
deformable substrate. The dynamical properties (fixed points, eigenvalues,
basins of attraction) of this map provide insights into efficient, responsive,
and robust locomotion on deformable terrain. Specifically, we identify
constant-fixed-point surfaces in a controller parameter space that suggest it
is possible to tune control parameters for efficiency or responsiveness while
targeting a desired gait energy level. We also identify conditions under which
fixed points of the energy map are globally stable, and we further characterize
the basins of attraction of fixed points when these conditions are not
satisfied. We conclude by discussing the implications of this hop-to-hop energy
map for planning, control, and estimation for efficient, agile, and robust
legged locomotion on deformable terrain.Comment: 17 pages, 13 figures, submitted to IEEE Transactions on Robotic
High-speed chromatic dispersion monitoring of a two-channel WDM system using a single TPA microcavity
Chromatic dispersion monitoring of two 160 Gb/s wavelength channels using a TPA Microcavity is presented. As the microcavity exhibits a wavelength resonance characteristic, a single device could monitor a number of different WDM-channels sequentially
Wavelength tuneable pulse monitoring using a Two-Photon-Absorption microcavity
Two Photon Absorption (TPA) is a non-linear optical-to-electrical conversion process that can be significantly enhanced by placing the active region within a resonance microcavity. The experiment confirmed the potential use of the microcavity structure for monitoring a single channel in multi-wavelength systems. The cavity can be designed for different applications depending on desired resonance width or cavity life time allowing the contrast ratio to be further improved. Due to the possibility of tuning the resonance wavelength by cavity tilting, a single device can be used to monitor a number of WDM channels without the need for additional optical filters
Resonance tuning of two-photon absorption microcavities for wavelength-selective pulse monitoring
We show the potential use of a single photodetector for multichannel pulse monitoring. Two-photon absorption in a microcavity structure is used as the nonlinear optical technique for pulse monitoring. Angle tuning of the device allows the resonance to be tuned. For the device studied here that is optimized for 2-ps pulses, a possible tuning range of 55 nm is shown
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