4,832 research outputs found

### Effective application of service core in a reinforced concrete tall building

This paper provides an outline of conducting the analysis and illustrates the behavior of high-rise structures
including lateral stiffness, dynamic response (period, acceleration) and human comfort criteria, in the context of the British Standard and National Building Code of Canada

### Ferroelectricity of Ice Nanotubes inside Carbon Nanotubes

We report that ice nanotubes with odd number of side faces inside carbon
nanotubes exhibit spontaneous electric polarization along its axes direction by
using molecular dynamics simulations. The mechanism of this nanoscale
quasi-one-dimensional ferroelectricity is due to low dimensional confinement
and the orientational order of hydrogen bonds. These ferroelectric fiber
structural materials are different from traditional perovskite structural bulk
materials.Comment: 4 pages and 4 figure

### Bulk-fragment and tube-like structures of AuN (N=2-26)

Using the relativistic all-electron density-functional calculations on the
AuN (N=2-26) in the generalized gradient approximation, combined with the
guided simulated annealing, we have found that the two- to three-dimensional
structural transition for AuN occurs between N=13 and 15, and the AuN (16<= N
<=25) prefer also the pyramid-based bulk fragment structures in addition to the
Au20. More importantly, the tubelike structures are found to be the most stable
for Au24 and Au26, offering another powerful structure competitor with other
isomers, e.g., amorphous, bulk fragment, and gold fullerene. The mechanism to
cause these unusual AuN may be attributed to the stronger s-d hybridization and
the d-d interaction enhanced by the relativistic effects.Comment: 12 pages and 3 figure

### Quantum interference in deformed carbon nanotube waveguides

Quantum interference (QI) in two types of deformed carbon nanotubes (CNTs),
i.e., axially stretched and AFM tip-deformed CNTs, has been investigated by the
pi-electron only and four-orbital tight-binding (TB) method. It is found that
the rapid conductance oscillation (RCO) period is very sensitive to the applied
strains, and decreases in an inverse proportion to the deformation degree,
which could be used as a powerful experimental tool to detect precisely the
deformation degree of the deformed CNTs. Also, the sigma-pi coupling effect is
found to be negligible under axially stretched strain, while it works on the
transport properties of the tip-deformed CNTs.Comment: 14 pages and 5 figure

### The Age-Redshift Relationship of Old Passive Galaxies

We use 32 age measurements of passively evolving galaxies as a function of
redshift to test and compare the standard model ($\Lambda$CDM) with the $R_{\rm
h}=ct$ Universe. We show that the latter fits the data with a reduced
$\chi^2_{\rm dof}=0.435$ for a Hubble constant $H_{0}= 67.2_{-4.0}^{+4.5}$ km
$\rm s^{-1}$ $\rm Mpc^{-1}$. By comparison, the optimal flat $\Lambda$CDM
model, with two free parameters (including $\Omega_{\rm
m}=0.12_{-0.11}^{+0.54}$ and $H_{0}=94.3_{-35.8}^{+32.7}$ km $\rm s^{-1}$ $\rm
Mpc^{-1}$), fits the age-\emph{z} data with a reduced $\chi^2_{\rm dof}=0.428$.
Based solely on their $\chi^2_{\rm dof}$ values, both models appear to account
for the data very well, though the optimized $\Lambda$CDM parameters are only
marginally consistent with those of the concordance model ($\Omega_{\rm
m}=0.27$ and $H_{0}= 70$ km $\rm s^{-1}$ $\rm Mpc^{-1}$). Fitting the age-$z$
data with the latter results in a reduced $\chi^2_{\rm dof}=0.523$. However,
because of the different number of free parameters in these models, selection
tools, such as the Akaike, Kullback and Bayes Information Criteria, favour
$R_{\rm h}=ct$ over $\Lambda$CDM with a likelihood of $\sim 66.5\%-80.5\%$
versus $\sim 19.5\%-33.5\%$. These results are suggestive, though not yet
compelling, given the current limited galaxy age-$z$ sample. We carry out Monte
Carlo simulations based on these current age measurements to estimate how large
the sample would have to be in order to rule out either model at a $\sim
99.7\%$ confidence level. We find that if the real cosmology is $\Lambda$CDM, a
sample of $\sim 45$ galaxy ages would be sufficient to rule out $R_{\rm h}=ct$
at this level of accuracy, while $\sim 350$ galaxy ages would be required to
rule out $\Lambda$CDM if the real Universe were instead $R_{\rm h}=ct$.Comment: 36 pages, 13 figures, 1 table; accepted for publication in The
Astronomical Journal. arXiv admin note: text overlap with arXiv:1405.238

- â€¦