1,635 research outputs found
General Operations Plan for the SEPTA Regional High Speed System
The purpose of this project has been to plan line pairings in the unified Regional High Speed Lines (RHSL) network when the Center City Tunnel is opened. While detailed schedules were not part of this project, headways and train consists have been determined for all lines for peak and off-peak periods
A Plan for SEPTA\u27s Regional Metrorail System
This report presents a plan for an investment, physical and operational upgrading of the RGR System. The intent of this plan should be creation of a modern Regional Metrorail System, more similar to such electrified regional rapid transit systems as the Washington Metrorail, Atlanta\u27s MARTA and San Francisco\u27s BART than to diesel-powered commuter rail systems, such as the Chicago METRA or the new Los Angeles Metrolink
Recommendations for Improvement of Green Lines Subway Operations
The purpose of this project is to analyze present operations of the Green Lines in the subway and develop solutions to the operational problems, so that the great potential of the subway for high performance and an attractive level of service for passengers can be fully realized
Kaluza-Klein bubble like structure and celestial sphere in inflationary universe
We consider five dimensional deSitter spacetimes with a deficit angle due to
the presence of a closed 2-brane and identify one dimension as an extra
dimension. From the four dimensional viewpoint we can see that the spacetime
has a structure similar to a Kaluza-Klein bubble of nothing, that is, four
dimensional spacetime ends at the 2-brane. Since a spatial section of the full
deSitter spacetime has the topology of a sphere, the boundary surface surrounds
the remaining four dimensional spacetime, and can be considered as the
celestial sphere. After the spacetime is created from nothing via an instanton
which we describe, some four dimensional observers in it see the celestial
sphere falling down, and will be in contact with a 2-brane attached on it.Comment: 5pages, 4figures, to be published in GR
Infrastructure and Operational Improvements of the SEPTA Regional Rail System
Since its takeover of the Regional Rail System from Conrail in 1983, SEPTA has made numerous efforts to adjust its facilities and operations to the needs of a modern regional rail system. In order to meet the needs of a modern transit-type operations of regional rail with shorter headways and greater operational flexibility, the infrastructure, such as track layout and signals, is one of the elements that requires changes. The current infrastructure was originally designed for freight and long distance railroad operations. This study represents part of SEPTA\u27s efforts to modernize its regional rail infrastructure and operations in a cost effective way
Interplay between structure and magnetism in nanowires
We investigate the equilibrium geometry and electronic structure of
MoSI nanowires using ab initio Density Functional
calculations. The skeleton of these unusually stable nanowires consists of
rigid, functionalized Mo octahedra, connected by flexible, bi-stable sulphur
bridges. This structural flexibility translates into a capability to stretch up
to approximate 20% at almost no energy cost. The nanowires change from
conductors to narrow-gap magnetic semiconductors in one of their structural
isomers.Comment: 4 pages with PRL standards and 3 figure
Soybean oil methanolysis over scallop shell-derived CaO prepared via methanol-assisted dry nano-grinding
Calcium oxides with a specific surface area between 4.5 m2g-1 and 62.5 m2g-1 were obtained by calcination of scallop shells, following by methanol-assisted dry nano-grinding. Three distinct phases are formed on the surface of these catalysts during nano-grinding: calcium methoxide, calcium hydroxide, and calcium oxide. The effects of specific surface area and active surface phase composition on the catalytic activity of calcium oxide during methanolysis of soybean oil were investigated. The properties of the calcium oxide before, during, and after methanol assisted dry nano-grinding were studied by XRD, FTIR, and nitrogen gas adsorption based on the BET method. The ground calcium oxides were found to be effective in catalyzing the methanolysis of soybean oil, with the optimal catalyst producing a 72.3% ester yield after 20 mins of reaction. The improvements in rate of reaction were attributed to the rapid formation of calcium diglyceroxide during the initial stages of methanolysis. A combination high specific surface area and effective active phases on the surface of the calcium oxide catalysts is correlated with reductions in mass transfer limitations in the early steps of the reaction, indicated by the rapid formation of calcium diglyceroxide
Morphological and Structural Changes in Microcrystalline Cellulose from OPEFB by Mechanical Grinding
Microcrystalline cellulose derived from oil palm empty fruit bunch (OPEFB) was grinded in planetary ball mill with dry state (without solvent) and solvent-assisted (ethanol and acetone). The effect of dry state and solvent-assisted on morphological and structural changes of microcrystalline cellulose were investigated. The structure changes, including particle size, powder morphology, crystalline structure, and molecular structure during the mechanical grinding were investigated by Laser Diffraction Particle Size Analyzer, SEM, XRD and FT-IR, respectively. The original fibrous microcrystalline cellulose was changed into irregular shape with finer micronized particles by dry state and solvent-assisted. SEM results showed that solvent-assisted significantly prevented the agglomeration phenomena during the grinding process, compared to dry state. The crystallinity after 4h solvent-assisted grinding showed fairly low crystallinity, while amorphous characteristic was observed with dry state grinding. The solvent-assisted led the hydrophilic parts of microcrystalline cellulose become stiff during the grinding that might be less deformed, leading to a fairly retain in crystallinity. The finer micronized particles were obtained under acetone-assisted and its crystallinity was fairly kept. XRD results indicated that crystalline form of origin microcrystalline was not changed by mechanical grinding
The Three Site Model at One-Loop
In this paper we compute the one-loop chiral logarithmic corrections to all
O(p^4) counterterms in the three site Higgsless model. The calculation is
performed using the background field method for both the chiral- and
gauge-fields, and using Landau gauge for the quantum fluctuations of the gauge
fields. The results agree with our previous calculations of the
chiral-logarithmic corrections to the S and T parameters in 't Hooft-Feynman
gauge. The work reported here includes a complete evaluation of all one-loop
divergences in an SU(2) x U(1) nonlinear sigma model, corresponding to an
electroweak effective Lagrangian in the absence of custodial symmetry.Comment: 40 pages, nine included eps figures. Minor corrections mad
Enrichment of the r-process Element Europium in the Galactic Halo
We investigate the enrichment of europium, as a representative of r-process
elements, in the Galactic halo. In present chemical evolution models, stars are
assumed to be formed through shock processes by supernovae (SNe). The
enrichment of the interstellar medium is calculated by a one-zone approach. The
observed large dispersions in [Eu/Fe] for halo stars, converging with
increasing metallicity, can be explained with our models. In addition, the mass
range of SNe for the {\it r}-process site is constrained to be either stars of
or .Comment: 5 pages (including 4 figures), LaTeX, uses aas2pp4.sty, accepted to
ApJ
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