23,809 research outputs found
The Power of Encouragement: The Role of Christian Academic Librarians in Supporting the Whole Student
Christian librarians are exhorted to consider the role of providing encouragement, care, and emotional and spiritual support to college students. Caring for the whole student can have a positive impact on college student success and retention, as well as have a transformational effect on students’ spiritual lives. By treating college students as whole persons created in the image of God, Christians academic librarians can not only help these students succeed by meeting their academic needs, but also help students thrive by supporting them emotionally and spiritually
Cryogenic loss monitors with FPGA TDC signal processing
Radiation hard helium gas ionization chambers capable of operating in vacuum
at temperatures ranging from 5K to 350K have been designed, fabricated and
tested and will be used inside the cryostats at Fermilab's Superconducting
Radiofrequency beam test facility. The chamber vessels are made of stainless
steel and all materials used including seals are known to be radiation hard and
suitable for operation at 5K. The chambers are designed to measure radiation up
to 30 kRad/hr with sensitivity of approximately 1.9 pA/(Rad/hr). The signal
current is measured with a recycling integrator current-to-frequency converter
to achieve a required measurement capability for low current and a wide dynamic
range. A novel scheme of using an FPGA-based time-to-digital converter (TDC) to
measure time intervals between pulses output from the recycling integrator is
employed to ensure a fast beam loss response along with a current measurement
resolution better than 10-bit. This paper will describe the results obtained
and highlight the processing techniques used.Comment: 7 pp. 2nd International Conference on Technology and Instrumentation
in Particle Physics 2011: TIPP 2011. 9-14 Jun 2011. Chicago, Illinoi
Quark Potentials in the Higgs Phase of Large N Supersymmetric Yang-Mills Theories
We compute, in the large N limit, the quark potential for
supersymmetric SU(N) Yang-Mills theory broken to . At
short distances the quarks see only the unbroken gauge symmetry and have an
attractive potential that falls off as 1/L. At longer distances the interquark
interaction is sensitive to the symmetry breaking, and other QCD states appear.
These states correspond to combinations of the quark-antiquark pair with some
number of W-particles. If there is one or more W-particles then this state is
unstable because of the coulomb interaction between the W-particles and between
the W's and the quarks. As L is decreased the W-particles delocalize and these
coulomb branches merge onto a branch with a linear potential. The quarks on
this branch see the unbroken gauge group, but the flux tube is unstable to the
production of W-particles.Comment: 23 pages, 7 figures, harvmac (b
Supersoft elasticity in polydomain nematic elastomers
We consider the equilibrium stress-strain behavior of polydomain liquid crystal elastomers (PLCEs). We show that there is a fundamental difference between PLCEs cross-linked in the high temperature isotropic and low temperature aligned states. PLCEs cross-linked in the isotropic state then cooled to an aligned state will exhibit extremely soft elasticity (confirmed by recent experiments) and ordered director patterns characteristic of textured deformations. PLCEs cross-linked in the aligned state will be mechanically much harder and characterized by disclination textures
Elasticity of Polydomain Liquid Crystal Elastomers
We model polydomain liquid-crystal elastomers by extending the neo-classical
soft and semi-soft free energies used successfully to describe monodomain
samples. We show that there is a significant difference between polydomains
cross-linked in homogeneous high symmetry states then cooled to low symmetry
polydomain states and those cross-linked directly in the low symmetry
polydomain state. For example, elastomers cross-linked in the isotropic state
then cooled to a nematic polydomain will, in the ideal limit, be perfectly
soft, and with the introduction of non-ideality, will deform at very low stress
until they are macroscopically aligned. The director patterns observed in them
will be disordered, characteristic of combinations of random deformations, and
not disclination patterns. We expect these samples to exhibit elasticity
significantly softer than monodomain samples. Polydomains cross-linked in the
nematic polydomain state will be mechanically harder and contain characteristic
schlieren director patterns. The models we use for polydomain elastomers are
spatially heterogeneous, so rather than solving them exactly we elucidate this
behavior by bounding the energies using Taylor-like (compatible test strain
fields) and Sachs (constant stress) limits extended to non-linear elasticity.
Good agreement is found with experiments that reveal the supersoft response of
some polydomains. We also analyze smectic polydomain elastomers and propose
that polydomain SmC* elastomers cross-linked in the SmA monodomain state are
promising candidates for low field electrical actuation.Comment: 13 pages, 11 figure
- …