43,616 research outputs found
Dynamics of Dry Friction: A Numerical Investigation
We perform extended numerical simulation of the dynamics of dry friction,
based on a model derived from the phenomenological description proposed by T.
Baumberger et al.. In the case of small deviation from the steady sliding
motion, the model is shown to be equivalent to the state- and rate-dependent
friction law which was first introduced by Rice and Ruina on the basis of
experiments on rocks. We obtain the dynamical phase diagram that agrees well
with the experimental results on the paper-on-paper systems. In particular, the
bifurcation between stick-slip and steady sliding are shown to change from a
direct (supercritical) Hopf type to an inverted (subcritical) one as the
driving velocity increases, in agreement with the experiments.Comment: 7 pages, 5 figures, using RevTe
Recommended from our members
Images of resistance: A photonarrative enquiry into the meanings of personal artwork for people living with cancer
This study explored the meanings, inspirations and subjective significance of personal artwork created as a leisure activity by women living with cancer. A convenience sample of twelve women aged between 23-74 years participated in semi-structured interviews. Participants were living in various stages of the cancer trajectory, and engaged in several forms of visual art-making. They submitted examples of their artwork by photograph and then participated in semi-structured interviews. From a phenomenological analysis, the authors inferred a number of themes. Participants perceived a few pieces, made during chemotherapy, as expressing deeper feelings about cancer in symbolic terms. More prevalent in participants’ accounts were references to their artwork as a sensuous pleasure, and its confirmation of their ongoing capability, personal continuity and social connectedness. Participants acknowledged ongoing loss and difficulties related to cancer. However, each piece of art offered a measure of resistance against the psychologically and socially disruptive effects of cancer. The pre-interview photography activity was helpful for empowering participants in the interview, and for stimulating detailed memories and associations
Modeling the Psychology of Consumer and Firm Behavior with Behavioral Economics
Marketing is an applied science that tries to explain and influence how firms and
consumers actually behave in markets. Marketing models are usually applications of
economic theories. These theories are general and produce precise predictions, but they
rely on strong assumptions of rationality of consumers and firms. Theories based on
rationality limits could prove similarly general and precise, while grounding theories in
psychological plausibility and explaining facts which are puzzles for the standard
approach.
Behavioral economics explores the implications of limits of rationality. The goal is to
make economic theories more plausible while maintaining formal power and accurate
prediction of field data. This review focuses selectively on six types of models used in
behavioral economics that can be applied to marketing.
Three of the models generalize consumer preference to allow (1) sensitivity to reference
points (and loss-aversion); (2) social preferences toward outcomes of others; and (3)
preference for instant gratification (quasi-hyperbolic discounting). The three models are
applied to industrial channel bargaining, salesforce compensation, and pricing of virtuous
goods such as gym memberships. The other three models generalize the concept of gametheoretic
equilibrium, allowing decision makers to make mistakes (quantal response
equilibrium), encounter limits on the depth of strategic thinking (cognitive hierarchy),
and equilibrate by learning from feedback (self-tuning EWA). These are applied to
marketing strategy problems involving differentiated products, competitive entry into
large and small markets, and low-price guarantees.
The main goal of this selected review is to encourage marketing researchers of all kinds
to apply these tools to marketing. Understanding the models and applying them is a
technical challenge for marketing modelers, which also requires thoughtful input from
psychologists studying details of consumer behavior. As a result, models like these could
create a common language for modelers who prize formality and psychologists who prize
realism
Boron-oxygen defect imaging in p-type Czochralski silicon
In this work, we demonstrate an accurate method for determining the effective boron-oxygen (BO) related defect density on Czochralski-grown silicon wafers using photoluminescence imaging. Furthermore, by combining a recently developed dopant density imaging technique and microscopic Fourier transform infrared spectroscopy measurements of the local interstitial oxygen concentration [Oi ], the BO-related defect density, [Oi ], and the boron dopant density from the same wafer were determined, all with a spatial resolution of 160 μm. The results clearly confirm the established dependencies of the BO-related defect density on [Oi ] and the boron dopant density and demonstrate a powerful technique for studying this important defect.This work was supported by the Australian Research
Council (ARC) Future Fellowships program and the
Australian Renewable Energy Agency (ARENA) fellowships
program
3-pt Statistics of Cosmological Stochastic Gravitational Waves
We consider the 3-pt function (i.e. the bispectrum or non-Gaussianity) for
stochastic backgrounds of gravitational waves. We estimate the amplitude of
this signal for the primordial inflationary background, gravitational waves
generated during preheating, and for gravitational waves produced by
self-ordering scalar fields following a global phase transition. To assess
detectability, we describe how to extract the 3-pt signal from an idealized
interferometric experiment and compute the signal to noise ratio as a function
of integration time. The 3-pt signal for the stochastic gravitational wave
background generated by inflation is unsurprisingly tiny. For gravitational
radiation generated by purely causal, classical mechanisms we find that, no
matter how non-linear the process is, the 3-pt correlations produced vanish in
direct detection experiments. On the other hand, we show that in scenarios
where the B-mode of the CMB is sourced by gravitational waves generated by a
global phase transition, a strong 3-pt signal among the polarization modes
could also be produced. This may provide another method of distinguishing
inflationary B-modes. To carry out this computation, we have developed a
diagrammatic approach to the calculation of stochastic gravitational waves
sourced by scalar fluids, which has applications beyond the present scenario.Comment: 16 pages, 5 figure
- …