3,175 research outputs found
Homeownership is Still Out of Reach for Millions of Households
Homeownership has long been the leading source of household wealth in the U.S. However, the most recent housing crash stripped many Americans of much of their wealth, as home values plummeted and millions of homes went into foreclosure. These losses were especially painful for homeowners of color, who lost a greater share of wealth in the crash and have rebuilt their wealth more slowly in the recovery. Now, as the housing market recovers and interest rates remain low, many Americans find themselves without the savings or access to credit necessary to be able to purchase a home. Although homeownership is not the best option for every household, many Americans who could greatly benefit from it are still excluded
Industrial innovation: A guide to Community action, services and funding. Second edition. EUR 9120 EN
Temporal distortion of annual modulation at low recoil energies
We show that the main features of the annual modulation of the signal
expected in a WIMP direct detection experiment, i.e. its sinusoidal dependence
with time, the occurrence of its maxima and minima during the year and (under
some circumstances) even the one-year period, may be affected by relaxing the
isothermal sphere hypothesis in the description of the WIMP velocity phase
space. The most relevant effect is a distortion of the time-behaviour at low
recoil energies for anisotropic galactic halos. While some of these effects
turn out to be relevant at recoil energies below the current detector
thresholds, some others could already be measurable, although some degree of
tuning between the WIMP mass and the experimental parameters would be required.
Either the observation or non-observation of these effects could provide clues
on the phase space distribution of our galactic halo.Comment: 4 pages, 4 figures, typeset with ReVTeX4. The paper may also be found
at http://www.to.infn.it/~fornengo/papers/distortion.ps.g
Rural Facility Electric Power Quality Analysis
This report gives results of a recently completed data collection and analysis project investigating electric power quality of two isolated utility systems in Alaska. This is the second phase of a similar effort reported in 1984 which provided the first comprehensive power quality data from four small Alaskan communities. In this report, second generation instrumentation is described and comprehensive data and data analyses are presented. These data are important because of the increased use throughout Alaska of electrical and electronic equipment that may be damage by power system disturbances.Abstract - iv
1.0 Introduction - 1
1.1 Site descriptions - 1
1.2 Power quality definitions and disturbance analyzzer outputs - 2
2.0 Second Generation Instrumentation - 4
2.1 Hardware - 4
2.2 Software development and utilization - 8
3.0 Power System Disturbance Data - 9
3.1 Kotzebue site - 10
Figure Descriptions - 10
3.1.1 808: - 10
3.1.2 626: - 13
3.1.2.1 Impulse - 13
3.1.2.2 Sag - 16
3.1.2.3 Surge - 18
3.1.2.4 Frequency Disturbances - 21
3.1.2.5 Voltages - 23
Figures K1-K85 - 24-66
3.2 Tazlina site - 67
Figure Descriptions - 67
3.2.1 808: - 67
3.2.2 626: - 71
3.2.2.1 Impulse - 1
3.2.2.2 Sag - 74
3.2.2.3 Surge - 77
3.2.2.4 Frequency Disturbances - 81
3.2.2.5 Voltages - 83
Figures T1 - T102 - 85-135
3.3 Power system disturbance data summary - 136
3.3.1 Kotzebue site - 136
3.3.2 Tazlina site - 142
4.0 Conclusions - 147
5.0 Acknowledgements - 154
6.0 References - 154
7.0 Selected Bibliography - 155
8.0 Appendix
Do current WIMP direct measurements constrain light relic neutralinos?
New upper bounds on direct detection rates have recently been presented by a
number of experimental collaborations working on searches for WIMPs. In this
paper we analyze how the constraints on relic neutralinos which can be derived
from these results is affected by the uncertainties in the distribution
function of WIMPs in the halo. Various different categories of velocity
distribution functions are considered, and the ensuing implications for
supersymmetric configurations derived. We conservatively conclude that current
experimental data do not constrain neutralinos of small mass (below 50 GeV).Comment: 9 pages, 7 figures, typeset with ReVTeX4. The paper may also be found
at http://www.to.infn.it/~fornengo/papers/constraints05.ps.gz or through
http://www.astroparticle.to.infn.it/index.htm
Effects of serum proteins on corrosion behavior of ISO 5832–9 alloy modified by titania coatings
Stainless steel ISO 5832–9 type is often used to
perform implants which operate in protein-containing physiological
environments. The interaction between proteins and
surface of the implant may affect its corrosive properties. The
aim of this work was to study the effect of selected serum
proteins (albumin and γ-globulins) on the corrosion of ISO
5832–9 alloy (trade name M30NW) which surface was modified
by titania coatings. These coatings were obtained by sol–
gel method and heated at temperatures of 400 and 800 °C. To
evaluate the effect of the proteins, the corrosion tests were
performed with and without the addition of proteins with
concentration of 1 g L−1 to the physiological saline solution
(0.9 % NaCl, pH 7.4) at 37 °C. The tests were carried out
within 7 days. The following electrochemical methods were
used: open circuit potential, linear polarization resistance, and
electrochemical impedance spectroscopy. In addition, surface
analysis by optical microscopy and X-ray photoelectron spectroscopy
(XPS) method was done at the end of weekly corrosion
tests. The results of corrosion tests showed that M30NW
alloy both uncoated and modified with titania coatings exhibits
a very good corrosion resistance during weekly exposition
to corrosion medium. The best corrosion resistance in
0.9 % NaCl solution is shown by alloy samples modified by
titania coating annealed at 400 °C. The serumproteins have no
significant effect onto corrosion of investigated biomedical
steel. The XPS results confirmed the presence of proteins on
the alloy surface after 7 days of immersion in proteincontaining
solutions.The investigations were supported by the National Science Centre project No. N N507 501339. The authors gratefully acknowledge Dr. Janusz
Sobczak and Dr. hab. Wojciech Lisowski from Institute of Physical
Chemistry of PAS for XPS surface analyses
Effect of Election Day Vote Centers on Voter Participation
In this article we study the effects of Election Day vote centers on voter turnout. Specifically we examine
Texas and Colorado’s experience with alternative arrangements for the number and location of Election
Day voting places and its impact on voter turnout in the 2006 and 2008 elections. We test our hypotheses
at both the aggregate (i.e., county) and individual levels. We find evidence that vote centers increase voter
turnout in presidential and midterm elections, and particularly among infrequent voters in midterms
Displacements analysis of self-excited vibrations in turning
The actual research deals with determining by a new protocol the necessary
parameters considering a three-dimensional model to simulate in a realistic way
the turning process on machine tool. This paper is dedicated to the
experimental displacements analysis of the block tool / block workpiece with
self-excited vibrations. In connexion with turning process, the self-excited
vibrations domain is obtained starting from spectra of two accelerometers. The
existence of a displacements plane attached to the tool edge point is revealed.
This plane proves to be inclined compared to the machines tool axes. We
establish that the tool tip point describes an ellipse. This ellipse is very
small and can be considered as a small straight line segment for the stable
cutting process (without vibrations). In unstable mode (with vibrations) the
ellipse of displacements is really more visible. A difference in phase occurs
between the tool tip displacements on the radial direction and on the cutting
one. The feed motion direction and the cutting one are almost in phase. The
values of the long and small ellipse axes (and their ratio) shows that these
sizes are increasing with the feed rate value. The axis that goes through the
stiffness center and the tool tip represents the maximum stiffness direction.
The maximum (resp. minimum) stiffness axis of the tool is perpendicular to the
large (resp. small) ellipse displacements axis. FFT analysis of the
accelerometers signals allows to reach several important parameters and
establish coherent correlations between tool tip displacements and the static -
elastic characteristics of the machine tool components tested
Fitting functions for a disk-galaxy model with different LCDM-halo profiles
We present an adaptation of the standard scenario of disk-galaxy formation to
the concordant LCDM cosmology aimed to derive analytical expressions for the
scale length and rotation speed of present-day disks that form within four
different, cosmologically motivated protogalactic dark matter halo-density
profiles. We invoke a standard galaxy-formation model that includes virial
equilibrium of spherical dark halos, specific angular momentum conservation
during gas cooling, and adiabatic halo response to the gas inflow. The mean
mass-fraction and mass-to-light ratio of the central stellar disk are treated
as free parameters whose values are tuned to match the zero points of the
observed size-luminosity and circular speed-luminosity relations of galaxies.
We supply analytical formulas for the characteristic size and rotation speed of
disks built inside Einasto r^{1/6}, Hernquist, Burkert, and Navarro-Frenk-White
dark matter halos. These expressions match simultaneously the observed zero
points and slopes of the different correlations that can be built in the RVL
space of disk galaxies from plausible values of the galaxy- and star-formation
efficiencies
Mechanisms of the Vertical Secular Heating of a Stellar Disk
We investigate the nonlinear growth stages of bending instability in stellar
disks with exponential radial density profiles.We found that the unstable modes
are global (the wavelengths are larger than the disk scale lengths) and that
the instability saturation level is much higher than that following from a
linear criterion. The instability saturation time scales are of the order of
one billion years or more. For this reason, the bending instability can play an
important role in the secular heating of a stellar disk in the direction.
In an extensive series of numerical -body simulations with a high spatial
resolution, we were able to scan in detail the space of key parameters (the
initial disk thickness , the Toomre parameter , and the ratio of dark
halo mass to disk mass ). We revealed three distinct
mechanisms of disk heating in the direction: bending instability of the
entire disk, bending instability of the bar, and heating on vertical
inhomogeneities in the distribution of stellar matter.Comment: 22 pages including 8 figures. To be published in Astronomy Letters
(v.29, 2003
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