Low-Temperature Features of Nano-Particle Dynamics

In view of better characterizing possible quantum effects in the dynamics of nanometric particles, we measure the effect on the relaxation of a slight heating cycle. The effect of the field amplitude is studied; its magnitude is chosen in order to induce the relaxation of large particles (~7nm), even at very low temperatures (100mK). Below 1K, the results significantly depart from a simple thermal dynamics scenario.Comment: 1 tex file, 4 PostScript figure

Greening the Trust: Enforcing Pennsylvania\u27s Environmental Rights and Duties to Combat Climate Change

Over the last century, humans have warmed the planet by approximately 1.0°C. Pennsylvania’s average temperature has risen 1.8°F in the last hundred years, and climate scientists predict it will warm an additional 5.4°F by 2050. These rising temperatures create feedback loops, leading to warming that will eventually become irreversible. Warmer temperatures have already led to melting ice caps, rising sea levels, dangerous weather patterns, and food shortages. Human-produced greenhouse gases (GHG) are the largest contributing factor to this warming. The scientific community largely agrees that if humans do not reach carbon neutrality by 2050, damage to the climate will be irreparable. Beyond that point, it will be nearly impossible for humans to mitigate, let alone prevent, the worst of climate change’s impacts on the planet. For at least the last decade, scientists and environmental organizations have emphasized the need to take protective measures against climate change and have provided actionable steps for governments at every level. Above all, these groups have stressed the importance of reducing carbon emissions and have proposed guidelines to achieve that goal. These strategies include transitioning energy sources and industries to greener practices, investing in sustainable infrastructure and agricultural systems, and climate finance and carbon pricing programs. Some countries have taken these proposals seriously and implemented significant policies and legislation to combat climate change. The United States, particularly at the federal level, has ignored many of these recommendations for combatting climate change. Despite intense lobbying efforts and growing public support, Congress has failed to enact meaningful climate legislation. In recent years, the executive branch has rolled back many protective regulations. Constitutional jurisdiction requirements and the federal judiciary’s reluctance to recognize environmental rights have thus far posed insurmountable barriers to rights-based climate litigation. In light of these challenges at the federal level and the dwindling time remaining to correct course, states, with fewer threshold barriers posed by jurisdictional requirements, are an increasingly attractive forum for enforcing environmental rights. At the state level, officials can enact, implement, reinterpret, and amend policies, legislation, and constitutional provisions more quickly and with more flexibility than their federal counterparts. States, particularly in recent years, have taken advantage of that flexibility. As of 2011, twenty-two states have constitutional provisions that protect environmental concerns either as a civil right or as a general policy matter. Despite these amendments, enforcing environmental rights has proven challenging in many states. In 1971, Pennsylvanians voted to ratify the Environmental Rights Amendment (ERA) in Article I, Section 27 of the Commonwealth’s constitution. Unlike other states, Pennsylvania enumerates environmental protections in its Declaration of Rights, placing them alongside other fundamental rights, such as the freedom of speech and religion. Despite this elevation, early decisions from the Pennsylvania courts severely limited the ERA’s power. However, Pennsylvania courts have recently construed section 27 to protect Pennsylvanians’ environmental rights and impose certain duties on the Commonwealth. Pennsylvania’s ERA jurisprudence offers helpful legal principles that other states can tailor to their own constitutional frameworks to address climate change at a subnational level. In October of 2019, Pennsylvania Governor Tom Wolf signed Executive Order 2019-07, which directed the Commonwealth’s Department of Environmental Protection (DEP) to produce a plan by July 2020 to reduce Pennsylvania’s carbon emissions by either joining the Regional Greenhouse Gas Initiative (RGGI), a greenhouse gas cap and trade program, or establishing its own carbon emission reduction scheme. As participants in RGGI’s cap and trade system, nine states in the Northeast and mid-Atlantic region limit GHG emissions by selling carbon allowances in quarterly auctions, the proceeds of which are returned to participating states. In early 2020, the DEP presented its preliminary proposal for implementing a cap and trade program and has since continued through the regulatory rulemaking process. Despite this progress, the Commonwealth has not yet articulated how it will use the funds generated from RGGI’s allowance auctions. This Note argues that the Commonwealth not only has a duty to combat climate change by reducing carbon emissions but also has a duty under the ERA to invest the funds it earns through carbon allowance auctions into the conservation and protection of Pennsylvania’s environment. Part I examines the ERA’s purpose and early history. Part II analyzes recent court decisions that have established both the contours of Pennsylvanians’ environmental rights and the Commonwealth’s duties under the ERA. Part III explains the functionality of cap and trade systems generally and how RGGI currently operates. Part IV discusses how the Commonwealth’s duties under the ERA inform the administration of a cap and trade program and how Pennsylvania courts can enforce the fulfillment of those duties. Part V anticipates and addresses potential counterarguments regarding enforcement in light of separation of powers concerns and the sufficiency of RGGI in fulfilling the Commonwealth’s duties

Hands-On History: Lessons Of War, Lessons Of Art

The collaboration of writer Nancy Clayton and illustrator Susan Spellman has resulted in Draw History: Civil War, a noteworthy book that combines historical facts with step-by-step art lessons. Clayton, whose writing progresses smoothly from the first to the last page, slips at times into t...

Laser diagnostics for NTP fuel corrosion studies

Viewgraphs and explanations on laser diagnostics for nuclear thermal propulsion (NTP) fuel corrosion studies are presented. Topics covered include: NTP fuels; U-Zr-C system corrosion products; planar laser-induced fluorescence (PLIF); utilization of PLIF for corrosion product characterization of nuclear thermal rocket fuel elements under test; ZrC emission spectrum; and PLIF imaging of ZrC plume

Can unions provide what workers want? The case of the Queensland health and fitness industry

Sexual, social and employment success have been linked to the physical capital drawn from having aesthetic attributes of the socially idealized body. In certain workplace settings, such as health and fitness centres, the body becomes a mainstream commodity with physical capital affording the fitness worker a high degree of distinction and adoration as well as employment opportunities. The employment relationship is shaped by 'lookism', with both the employer and employee taking advantage of the fitness worker's idealized form. The worker's physical capital provides a walking billboard advertising the employer's products and services, while exposure to comparison and adoration provides a heightened sense of self-worth, distinction and celebrity for fitness workers for which they are prepared to trade-off employment conditions. In redefining what they want from work, fitness workers challenge the traditional purpose of trade unions, and question their ability to deliver what these workers want from their employment relationship

The Australian Domestic Pilots’ Dispute of 1989 and Its Implications: An Interpretation

The 1989 domestic pilots' dispute in Australia provided a stark demonstration of the underlying conflict and tensions of the neo-corporatist Prices and Incomes Accord. The pilots proposed a wage increase outside of the Accord guidelines but of comparable tnagnitude with the wagge increases received by senior executives within the airline sector and senior public servants. A protracted campaign saw the government and employers, with the tacit support of the ACIU, use a range of extreme measures against the Australian Federation of Air Pilots. Eventually, industrial peace was returned to the domestic airline sector. However, the costs, financial and emotional, of the dispute were considerable. The government restored industrial "order" but left considerable disquiet and division within the Australian trade union movement. The dispute established many important precedents for the business sector and the opposition Liberal/National Parties coalition in their push for labour market de-regulation in Australia

A new experimental procedure for characterizing quantum effects in small magnetic particle systems

A new experimental procedure is discussed, which aims at separating thermal from quantum behavior independently of the energy barrier distribution in small particle systems. Magnetization relaxation data measured between 60 mK and 5 K on a sample of nanoparticles is presented. The comparison between experimental data and numerical calculations shows a clear departure from thermal dynamics for our sample, which was not obvious without using the new procedure presented here.Comment: LaTeX source, 6 pages, 5 PostScript figure

Analysis of Cone-Beam Artifacts in off-Centered Circular CT for Four Reconstruction Methods

Cone-beam (CB) acquisition is increasingly used for truly three-dimensional X-ray computerized tomography (CT). However, tomographic reconstruction from data collected along a circular trajectory with the popular Feldkamp algorithm is known to produce the so-called CB artifacts. These artifacts result from the incompleteness of the source trajectory and the resulting missing data in the Radon space increasing with the distance to the plane containing the source orbit. In the context of the development of integrated PET/CT microscanners, we introduced a novel off-centered circular CT cone-beam geometry. We proposed a generalized Feldkamp formula (α-FDK) adapted to this geometry, but reconstructions suffer from increased CB artifacts. In this paper, we evaluate and compare four different reconstruction methods for correcting CB artifacts in off-centered geometry. We consider the α-FDK algorithm, the shift-variant FBP method derived from the T-FDK, an FBP method based on the Grangeat formula, and an iterative algebraic method (SART). The results show that the low contrast artifacts can be efficiently corrected by the shift-variant method and the SART method to achieve good quality images at the expense of increased computation time, but the geometrical deformations are still not compensated for by these techniques

Disentangling Distribution Effects and Nature of the Dynamics in Relaxation Measurements: the RMR Method

URL: http://www-spht.cea.fr/articles/s00/004 (sur invitation). Comment séparer les effets de distribution et la nature de la dynamique dans des mesures de relaxation magnétiques: la méthode RMRWe discuss here the nature of the low temperature magnetic relaxation in samples of magnetic nanoparticles. In addition to usual magnetic viscosity measurement, we have used the Residual Memory Ratio (RMR) method. This procedure enables us to overcome the uncertainties usually associated with the energy barrier distribution, thus giving a more detailed insight on the nature of the observed dynamics. A custom made apparatus coupling dilution refrigeration and SQUID magnetometry allowed measurements of very diluted samples at temperatures ranging between 60mK and 7K. Two types of particles have been studied: $\gamma$-Fe$_2$O$_3$ of moderate anisotropy, and CoFe$_2$O$_4$ of higher anisotropy where quantum effects are more likely to occur. In both cases, the data cannot simply be interpreted in terms of mere thermally activated dynamics of independent particles. The deviation from thermal activation seems to go opposite of what is expected from the possible effect of particle interactions. We therefore believe that it suggests the occurrence of quantum dynamics at very low temperatures