923 research outputs found
Crucial role of sidewalls in velocity distributions in quasi-2D granular gases
Our experiments and three-dimensional molecular dynamics simulations of
particles confined to a vertical monolayer by closely spaced frictional walls
(sidewalls) yield velocity distributions with non-Gaussian tails and a peak
near zero velocity. Simulations with frictionless sidewalls are not peaked.
Thus interactions between particles and their container are an important
determinant of the shape of the distribution and should be considered when
evaluating experiments on a tightly constrained monolayer of particles.Comment: 4 pages, 4 figures, Added reference, model explanation charified,
other minor change
Nurses\u27 Alumnae Association Bulletin, September 1958
Committee Reports
Digest of Alumnae Meetings
Graduation Awards - 1957
List of Wrong Addresses
Marriages
Necrology
New Arrivals
Physical Advances at Jefferson
President\u27s Message
School of Nursing Repor
Experimental evidence of non-Amontons behaviour at a multicontact interface
We report on normal stress field measurements at the multicontact interface
between a rough elastomeric film and a smooth glass sphere under normal load,
using an original MEMS-based stress sensing device. These measurements are
compared to Finite Elements Method calculations with boundary conditions
obeying locally Amontons' rigid-plastic-like friction law with a uniform
friction coefficient. In dry contact conditions, significant deviations are
observed which decrease with increasing load. In lubricated conditions, the
measured profile recovers almost perfectly the predicted profile. These results
are interpreted as a consequence of the finite compliance of the multicontact
interface, a mechanism which is not taken into account in Amontons' law
Role of friction-induced torque in stick-slip motion
We present a minimal quasistatic 1D model describing the kinematics of the
transition from static friction to stick-slip motion of a linear elastic block
on a rigid plane. We show how the kinematics of both the precursors to
frictional sliding and the periodic stick-slip motion are controlled by the
amount of friction-induced torque at the interface. Our model provides a
general framework to understand and relate a series of recent experimental
observations, in particular the nucleation location of micro-slip instabilities
and the build up of an asymmetric field of real contact area.Comment: 6 pages, 5 figure
The dynamics of thin vibrated granular layers
We describe a series of experiments and computer simulations on vibrated
granular media in a geometry chosen to eliminate gravitationally induced
settling. The system consists of a collection of identical spherical particles
on a horizontal plate vibrating vertically, with or without a confining lid.
Previously reported results are reviewed, including the observation of
homogeneous, disordered liquid-like states, an instability to a `collapse' of
motionless spheres on a perfect hexagonal lattice, and a fluctuating,
hexagonally ordered state. In the presence of a confining lid we see a variety
of solid phases at high densities and relatively high vibration amplitudes,
several of which are reported for the first time in this article. The phase
behavior of the system is closely related to that observed in confined
hard-sphere colloidal suspensions in equilibrium, but with modifications due to
the effects of the forcing and dissipation. We also review measurements of
velocity distributions, which range from Maxwellian to strongly non-Maxwellian
depending on the experimental parameter values. We describe measurements of
spatial velocity correlations that show a clear dependence on the mechanism of
energy injection. We also report new measurements of the velocity
autocorrelation function in the granular layer and show that increased
inelasticity leads to enhanced particle self-diffusion.Comment: 11 pages, 7 figure
fbl-typing of Staphylococcus lugdunensis: a frontline tool for epidemiological studies
International audienc
Nurses\u27 Alumnae Association Bulletin, April 1959
Alumnae News
Anniversary Class of /34
Article from Pennsylvania Nurse
Committee Reports
Current Events at Jefferson
Greetings from the President
Jefferson Story
Lost Members
Letter - Past President
Marriages
Necrology
New Arrivals
Notices
Pictured - Student Nurses\u27 Residence
Report of the School of Nursing and Nursing Services
Staff Nurses Social Functions
Student Activities
Voluntary Service
Year of Great Activity and Expansio
PHIL photoinjector test line
LAL is now equiped with its own platform for photoinjectors tests and
Research and Developement, named PHIL (PHotoInjectors at LAL). This facility
has two main purposes: push the limits of the photoinjectors performances
working on both the design and the associated technology and provide a low
energy (MeV) short pulses (ps) electron beam for the interested users. Another
very important goal of this machine will be to provide an opportunity to form
accelerator physics students, working in a high technology environment. To
achieve this goal a test line was realised equipped with an RF source, magnets
and beam diagnostics. In this article we will desrcibe the PHIL beamline and
its characteristics together with the description of the first two
photoinjector realised in LAL and tested: the ALPHAX and the PHIN RF Guns
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