74,476 research outputs found
Feasibility Of OneâDedicatedâLane Bus Rapid Transit âLightâRail Systems And Their Expansion To TwoâDedicatedâLane Systems: A Focus On Geometric Configuration And Performance Planning, MTI Report 08-01
This report consists primarily of two parts, the first on feasibility and the next on space minimization. In the section on feasibility, we propose the concept of a Bus Rapid Transit (BRT) or lightârail system that effectively requires only one dedicated but reversible lane throughout the system to support two-way traffic in the median of a busy commute corridor with regular provision of leftâturn lanes. Based on key ideas proposed in that section, the section on space minimization first addresses how to implement a twoâdedicatedâlane BRT or lightârail system with minimum rightâofâway width and then proposes ways to expand a oneâdedicatedâlane system to two dedicated lanes. In a oneâdedicatedâlane system, traffic crossing is accommodated on the otherwise unused or underused median space resulting from provision of the leftâturn lanes. Although not necessary, some leftâturn lanes can be sacrificed for bus stops. Conceptual design options and geometric configuration sketches for the bus stop and crossing space are provided in the section on feasibility, which also discusses system performance in terms of travel speed, headway of operations, distance between two neighboring crossing spaces, and number of crossing spaces. To ensure practicality, we study implementation of such a system on an existing corridor. Such a system is also useful as an intermediate step toward a twoâdedicatedâlane system because of its potential for facilitating transitâoriented development. In typical existing or planned BRT or lightârail systems implemented with two dedicated traffic lanes, a space equivalent to four traffic lanes is dedicated for a bus stop. In the section on space minimization, we propose implementations requiring only three lanes at a bus stop, based on two key ideas proposed for a oneâdedicatedâlane system. That section also discusses ways to expand a oneâdedicatedâlane system to its corresponding twoâdedicatedâlane system
The ordered K-theory of a full extension
Let A be a C*-algebra with real rank zero which has the stable weak
cancellation property. Let I be an ideal of A such that I is stable and
satisfies the corona factorization property. We prove that 0->I->A->A/I->0 is a
full extension if and only if the extension is stenotic and K-lexicographic. As
an immediate application, we extend the classification result for graph
C*-algebras obtained by Tomforde and the first named author to the general
non-unital case. In combination with recent results by Katsura, Tomforde, West
and the first author, our result may also be used to give a purely
K-theoretical description of when an essential extension of two simple and
stable graph C*-algebras is again a graph C*-algebra.Comment: Version IV: No changes to the text. We only report that Theorem 4.9
is not correct as stated. See arXiv:1505.05951 for more details. Since
Theorem 4.9 is an application to the main results of the paper, the main
results of this paper are not affected by the error. Version III comments:
Some typos and errors corrected. Some references adde
Spectrum of low-lying configurations with negative parity
Spectrum of low-lying five-quark configurations with strangeness quantum
number and negative parity is studied in three kinds of constituent
quark models, namely the one gluon exchange, Goldstone Boson exchange, and
instanton-induced hyperfine interaction models, respectively. Our numerical
results show that the lowest energy states in all the three employed models are
lying at 1800 MeV, about 200 MeV lower than predictions of various
quenched three-quark models. In addition, it is very interesting that the state
with the lowest energy in one gluon exchange model is with spin 3/2, but 1/2 in
the other two models.Comment: Version published in Phys. Rev.
Electronic Interface Reconstruction at Polar-Nonpolar Mott Insulator Heterojunctions
We report on a theoretical study of the electronic interface reconstruction
(EIR) induced by polarity discontinuity at a heterojunction between a polar and
a nonpolar Mott insulators, and of the two-dimensional strongly-correlated
electron systems (2DSCESs) which accompany the reconstruction. We derive an
expression for the minimum number of polar layers required to drive the EIR,
and discuss key parameters of the heterojunction system which control 2DSCES
properties. The role of strong correlations in enhancing confinement at the
interface is emphasized.Comment: 7 pages, 6 figures, some typos correcte
Probing the plateau-insulator quantum phase transition in the quantum Hall regime
We report quantum Hall experiments on the plateau-insulator transition in a
low mobility In_{.53} Ga_{.47} As/InP heterostructure. The data for the
longitudinal resistance \rho_{xx} follow an exponential law and we extract a
critical exponent \kappa= .55 \pm .05 which is slightly different from the
established value \kappa = .42 \pm .04 for the plateau transitions. Upon
correction for inhomogeneity effects, which cause the critical conductance
\sigma_{xx}^* to depend marginally on temperature, our data indicate that the
plateau-plateau and plateau- insulator transitions are in the same universality
class.Comment: 4 pages, 4 figures (.eps
Nonlinear lift and pressure distribution of slender conical bodies with strakes at low speeds
Nonlinear lift and pressure distribution of slender conical bodies with strakes at low spee
Controlling doping in graphene through a SiC substrate: A first-principles study
Controlling the type and density of charge carriers by doping is the key step
for developing graphene electronics. However, direct doping of graphene is
rather a challenge. Based on first-principles calculations, a concept of
overcoming doping difficulty in graphene via substrate is reported.We find that
doping could be strongly enhanced in epitaxial graphene grown on silicon
carbide substrate. Compared to free-standing graphene, the formation energies
of the dopants can decrease by as much as 8 eV. The type and density of the
charge carriers of epitaxial graphene layer can be effectively manipulated by
suitable dopants and surface passivation. More importantly, contrasting to the
direct doping of graphene, the charge carriers in epitaxial graphene layer are
weakly scattered by dopants due to the spatial separation between dopants and
the conducting channel. Finally, we show that a similar idea can also be used
to control magnetic properties, for example, induce a half-metallic state in
the epitaxial graphene without magnetic impurity doping
Cosmological Models and Latest Observational Data
In this note, we consider the observational constraints on some cosmological
models by using the 307 Union type Ia supernovae (SNIa), the 32 calibrated
Gamma-Ray Bursts (GRBs) at , the updated shift parameter from WMAP
5-year data (WMAP5), and the distance parameter of the measurement of the
baryon acoustic oscillation (BAO) peak in the distribution of SDSS luminous red
galaxies with the updated scalar spectral index from WMAP5. The tighter
constraints obtained here update the ones obtained previously in the
literature.Comment: 10 pages, 5 figures, 1 table, revtex4; v2: discussions added,
accepted by Eur. Phys. J. C; v3: published versio
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