243 research outputs found
Charging Ultra-nanoporous Electrodes with Size-asymmetric Ions Assisted by Apolar Solvent
We develop a statistical theory of charging quasi single-file pores with cations and anions of different sizes as well as solvent molecules or voids. This is done by mapping the charging onto a one-dimensional Blume–Emery–Griffith model with variable coupling constants. The results are supported by three-dimensional Monte Carlo simulations in which many limitations of the theory are lifted. We explore the different ways of enhancing the energy storage which depend on the competitive adsorption of ions and solvent molecules into pores, the degree of ionophilicity and the voltage regimes accessed. We identify new solvent-related charging mechanisms and show that the solvent can play the role of an “ionophobic agent”, effectively controlling the pore ionophobicity. In addition, we demonstrate that the ion-size asymmetry can significantly enhance the energy stored in a nanopore
Punishment and Preventing Pollution in Japan: Is American-Style Criminal Enforcement the Solution?
Both Japan and the United States face the ongoing threat of intentional and preventable pollution. From 1970 until the mid-1980s, Japan utilized its environmental crime laws to punish and prevent intentional and preventable acts of pollution. After this period, however, the number of environmental crime arrests and prosecutions in Japan declined. In contrast, since the 1980s, the United States has continued to expand the number of prosecutors and investigators dedicated to the enforcement of environmental crime laws. These divergent trends can be explained by the different pollution histories, enforcement personnel structures, regulatory strategies, and case law of the two countries. In recent years, Japan has been plagued by large oil spills and the illegal disposal of industrial waste. By aggressively enforcing its environmental crime laws and increasing criminal fines, Japan can better deter these types of pollution in the future
"Good Trouble": First Amendment Protections of Political Protest in Public Forums
Political protest has had a longstanding history within the United States, predating
the country’s formation. The First Amendment’s ratification in 1791 was integral to the
modernization of political protest, specifically the freedom of speech and assembly
clauses. However, with the evolution of the fledgling nation came a decreased tolerance
for the disorder, often associated with protests. After the change in the public’s regard for
protests, restrictions on political protests, such as permit requirements, were widely
introduced, narrowing the permissibility of certain aspects of political protest. Likewise,
protest’s forum and content restrictions are subject to differing levels of scrutiny and
permissible restrictions.
Recently, political protests have been brought to the forefront of the public’s
attention, yet there is a significant lack of literature on the legality of political protests
and the role of criminal justice actors in enforcing protest protections. The purpose of this
thesis is to provide an in-depth, legal discussion of political protest in public forums,
specifying the legal parameters of protected political protest. This thesis will utilize an
inductive, doctrinal methodology to examine the legal precedent established by the
United States Supreme Court and the modern interpretations and application of this
precedent by the U.S. Circuit Courts of Appeals. Specifically, the themes of protests and
protest restrictions will be examined in-depth
Critical adsorption on non-spherical colloidal particles
We consider a non-spherical colloidal particle immersed in a fluid close to
its critical point. The temperature dependence of the corresponding order
parameter profile is calculated explicitly. We perform a systematic expansion
of the order parameter profile in powers of the local curvatures of the surface
of the colloidal particle. This curvature expansion reduces to the short
distance expansion of the order parameter profile in the case that the solvent
is at the critical composition.Comment: 9 pages, 7 figure
Critical mass and the dependency of research quality on group size
Academic research groups are treated as complex systems and their cooperative
behaviour is analysed from a mathematical and statistical viewpoint. Contrary
to the naive expectation that the quality of a research group is simply given
by the mean calibre of its individual scientists, we show that intra-group
interactions play a dominant role. Our model manifests phenomena akin to phase
transitions which are brought about by these interactions, and which facilitate
the quantification of the notion of critical mass for research groups. We
present these critical masses for many academic areas. A consequence of our
analysis is that overall research performance of a given discipline is improved
by supporting medium-sized groups over large ones, while small groups must
strive to achieve critical mass.Comment: 16 pages, 6 figures consisting of 16 panels. Presentation and
reference list improved for version
Critical Casimir interaction of ellipsoidal colloids with a planar wall
Based on renormalization group concepts and explicit mean field calculations
we study the universal contribution to the effective force and torque acting on
an ellipsoidal colloidal particle which is dissolved in a critical fluid and is
close to a homogeneous planar substrate. At the same closest distance between
the substrate and the surface of the particle, the ellipsoidal particle prefers
an orientation parallel to the substrate and the magnitude of the fluctuation
induced force is larger than if the orientation of the particle is
perpendicular to the substrate. The sign of the critical torque acting on the
ellipsoidal particle depends on the type of boundary conditions for the order
parameter at the particle and substrate surfaces, and on the pivot with respect
to which the particle rotates
Theory and simulations of ionic liquids in nanoconfinement.
Room-temperature ionic liquids (RTILs) have exciting properties such as nonvolatility, large electrochemical windows, and remarkable variety, drawing much interest in energy storage, gating, electrocatalysis, tunable lubrication, and other applications. Confined RTILs appear in various situations, for instance, in pores of nanostructured electrodes of supercapacitors and batteries, as such electrodes increase the contact area with RTILs and enhance the total capacitance and stored energy, between crossed cylinders in surface force balance experiments, between a tip and a sample in atomic force microscopy, and between sliding surfaces in tribology experiments, where RTILs act as lubricants. The properties and functioning of RTILs in confinement, especially nanoconfinement, result in fascinating structural and dynamic phenomena, including layering, overscreening and crowding, nanoscale capillary freezing, quantized and electrotunable friction, and superionic state. This review offers a comprehensive analysis of the fundamental physical phenomena controlling the properties of such systems and the current state-of-the-art theoretical and simulation approaches developed for their description. We discuss these approaches sequentially by increasing atomistic complexity, paying particular attention to new physical phenomena emerging in nanoscale confinement. This review covers theoretical models, most of which are based on mapping the problems on pertinent statistical mechanics models with exact analytical solutions, allowing systematic analysis and new physical insights to develop more easily. We also describe a classical density functional theory, which offers a reliable and computationally inexpensive tool to account for some microscopic details and correlations that simplified models often fail to consider. Molecular simulations play a vital role in studying confined ionic liquids, enabling deep microscopic insights otherwise unavailable to researchers. We describe the basics of various simulation approaches and discuss their challenges and applicability to specific problems, focusing on RTIL structure in cylindrical and slit confinement and how it relates to friction and capacitive and dynamic properties of confined ions
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