33,767 research outputs found
Negative Linear Compressibility
While all materials reduce their intrinsic volume under hydrostatic (uniform)
compression, a select few actually \emph{expand} along one or more directions
during this process of densification. As rare as it is counterintuitive, such
"negative compressibility" behaviour has application in the design of pressure
sensors, artificial muscles and actuators. The recent discovery of surprisingly
strong and persistent negative compressibility effects in a variety of new
families of materials has ignited the field. Here we review the phenomenology
of negative compressibility in this context of materials diversity, placing
particular emphasis on the common structural motifs that recur amongst known
examples. Our goal is to present a mechanistic understanding of negative
compressibility that will help inform a clear strategy for future materials
design.Comment: Submitted to PCC
NASA TileWorld manual (system version 2.2)
The commands are documented of the NASA TileWorld simulator, as well as providing information about how to run it and extend it. The simulator, implemented in Common Lisp with Common Windows, encodes a particular range in a spectrum of domains, for controllable research experiments. TileWorld consists of a two dimensional grid of cells, a set of polygonal tiles, and a single agent which can grasp and move tiles. In addition to agent executable actions, there is an external event over which the agent has not control; this event correspond to a 'gust of wind'
Choosing Prevention Products: Questions to Ask When Considering Sexual and Relationship Violence and Stalking Prevention Products
The purpose of this white paper is to provide guidance to university and college leaders on how to choose products that address concerns of sexual and relationship violence and stalking from the perspective of prevention
Addressing Alcohol\u27s Role in Campus Sexual Assault: A Toolkit by and for Prevention Specialists
This toolkit provides specific guidance on addressing alcohol\u27s role in campus sexual assault, centering Sexual Assault Prevention Specialists as the intended audience
Design of crystal-like aperiodic solids with selective disorder--phonon coupling
Functional materials design normally focuses on structurally-ordered systems
because disorder is considered detrimental to many important physical
properties. Here we challenge this paradigm by showing that particular types of
strongly-correlated disorder can give rise to useful characteristics that are
inaccessible to ordered states. A judicious combination of low-symmetry
building unit and high-symmetry topological template leads to aperiodic
"procrystalline" solids that harbour this type of topological disorder. We
identify key classes of procrystalline states together with their
characteristic diffraction behaviour, and establish a variety of mappings onto
known and target materials. Crucially, the strongly-correlated disorder we
consider is associated with specific sets of modulation periodicities
distributed throughout the Brillouin zone. Lattice dynamical calculations
reveal selective disorder-phonon coupling to lattice vibrations characterised
by these same periodicities. The principal effect on the phonon spectrum is to
bring about dispersion in energy rather than wave-vector, as in the
poorly-understood "waterfall" effect observed in relaxor ferroelectrics. This
property of procrystalline solids suggests a mechanism by which
strongly-correlated topological disorder might allow new and useful
functionalities, including independently-optimised thermal and electronic
transport behaviour as required for high-performance thermoelectrics.Comment: 4 figure
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