Connecticut transit (CTTRANSIT) fuel cell transit bus: Third evaluation report and appendices

This report describes operations at Connecticut Transit (CTTRANSIT) in Hartford for one prototype fuel cell bus and three newer diesel buses operating from the same location. The prototype fuel cell bus was manufactured by Van Hool and ISE Corp. and features an electric hybrid drive system with a UTC Power PureMotion 120 Fuel Cell Power System and ZEBRA batteries for energy storage. The fuel cell bus started operation in April 2007, and evaluation results through October 2009 are provided in this report

SunLine Transit Agency Advanced Technology Fuel Cell Bus Evaluation: Second Results Report and Appendices

This report describes operations at SunLine Transit Agency for their newest prototype fuel cell bus and five compressed natural gas (CNG) buses. In May 2010, SunLine began operating its sixth-generation hydrogen fueled bus, an Advanced Technology (AT) fuel cell bus that incorporates the latest design improvements to reduce weight and increase reliability and performance. The agency is collaborating with the U.S. Department of Energy's (DOE) National Renewable Energy Laboratory (NREL) to evaluate the bus in revenue service. This is the second results report for the AT fuel cell bus since it was placed in service, and it focuses on the newest data analysis and lessons learned since the previous report. The appendices, referenced in the main report, provide the full background for the evaluation. They will be updated as new information is collected but will contain the original background material from the first report

The application of the global isomorphism to the surface tension of the liquid-vapor interface of the Lennard-Jones fluids

In this communication we show that the surface tension of the real fluids of the Lennard-Jones type can be obtained from the surface tension of the lattice gas (Ising model) on the basis of the global isomorphism approach developed earlier for the bulk properties.Comment: 8 pages, 6 figure

Early Cementation of the Short Creek Oolite Member, Boone Formation (Osagean, Lower Mississippian), Northern Arkansas

The Short Creek Oolite is the only formally named member of the Boone Formation in northern Arkansas. It lacks bedding features, and oolith concentrations that would suggest a shoal environment, and it occurs at variable stratigraphic horizons within the upper Boone Formation consistent with episodic deposition as grainflow slurries. As with modern oolite examples, such as Joulters Cays, Bahamas, the Short Creek preserves numerous intraclasts, and at least one large olistolith indicating an early cementation history

First Results from a 1.3 cm EVLA Survey of Massive Protostellar Objects: G35.03+0.35

We have performed a 1.3 centimeter survey of 24 massive young stellar objects (MYSOs) using the Expanded Very Large Array (EVLA). The sources in the sample exhibit a broad range of massive star formation signposts including Infrared Dark Clouds (IRDCs), UCHII regions, and extended 4.5 micron emission in the form of Extended Green Objects (EGOs). In this work, we present results for G35.03+0.35 which exhibits all of these phenomena. We simultaneously image the 1.3 cm ammonia (1,1) through (6,6) inversion lines, four methanol transitions, two H recombination lines, plus continuum at 0.05 pc resolution. We find three areas of thermal ammonia emission, two within the EGO (designated the NE and SW cores) and one toward an adjacent IRDC. The NE core contains an UCHII region (CM1) and a candidate HCHII region (CM2). A region of non-thermal, likely masing ammonia (3,3) and (6,6) emission is coincident with an arc of 44 GHz methanol masers. We also detect two new 25 GHz Class I methanol masers. A complementary Submillimeter Array 1.3 mm continuum image shows that the distribution of dust emission is similar to the lower-lying ammonia lines, all peaking to the NW of CM2, indicating the likely presence of an additional MYSO in this protocluster. By modeling the ammonia and 1.3 mm continuum data, we obtain gas temperatures of 20-220 K and masses of 20-130 solar. The diversity of continuum emission properties and gas temperatures suggest that objects in a range of evolutionary states exist concurrently in this protocluster.Comment: To appear in Astrophysical Journal Letters Special Issue on the EVLA. 16 pages, 3 figures. Includes the complete version of Figure 3, which was unable to fit into the journal article due to the number of panel

The Protocluster G18.67+0.03: A Test Case for Class I Methanol Masers as Evolutionary Indicators for Massive Star Formation

We present high angular resolution Submillimeter Array (SMA) and Karl G. Jansky Very Large Array (VLA) observations of the massive protocluster G18.67+0.03. Previously targeted in maser surveys of GLIMPSE Extended Green Objects (EGOs), this cluster contains three Class I methanol maser sources, providing a unique opportunity to test the proposed role of Class I masers as evolutionary indicators for massive star formation. The millimeter observations reveal bipolar molecular outflows, traced by 13CO(2-1) emission, associated with all three Class I maser sources. Two of these sources (including the EGO) are also associated with 6.7 GHz Class II methanol masers; the Class II masers are coincident with millimeter continuum cores that exhibit hot core line emission and drive active outflows, as indicated by the detection of SiO(5-4). In these cases, the Class I masers are coincident with outflow lobes, and appear as clear cases of excitation by active outflows. In contrast, the third Class I source is associated with an ultracompact HII region, and not with Class II masers. The lack of SiO emission suggests the 13CO outflow is a relic, consistent with its longer dynamical timescale. Our data show that massive young stellar objects associated only with Class I masers are not necessarily young, and provide the first unambiguous evidence that Class I masers may be excited by both young (hot core) and older (UC HII) MYSOs within the same protocluster.Comment: Astrophysical Journal Letters, accepted. emulateapj, 7 pages including 4 figures and 1 table. Figures compressed. v2: coauthor affiliation updated, emulateapj versio

Microcanonical Origin of the Maximum Entropy Principle for Open Systems

The canonical ensemble describes an open system in equilibrium with a heat bath of fixed temperature. The probability distribution of such a system, the Boltzmann distribution, is derived from the uniform probability distribution of the closed universe consisting of the open system and the heat bath, by taking the limit where the heat bath is much larger than the system of interest. Alternatively, the Boltzmann distribution can be derived from the Maximum Entropy Principle, where the Gibbs-Shannon entropy is maximized under the constraint that the mean energy of the open system is fixed. To make the connection between these two apparently distinct methods for deriving the Boltzmann distribution, it is first shown that the uniform distribution for a microcanonical distribution is obtained from the Maximum Entropy Principle applied to a closed system. Then I show that the target function in the Maximum Entropy Principle for the open system, is obtained by partial maximization of Gibbs-Shannon entropy of the closed universe over the microstate probability distributions of the heat bath. Thus, microcanonical origin of the Entropy Maximization procedure for an open system, is established in a rigorous manner, showing the equivalence between apparently two distinct approaches for deriving the Boltzmann distribution. By extending the mathematical formalism to dynamical paths, the result may also provide an alternative justification for the principle of path entropy maximization as well.Comment: 12 pages, no figur

Imaging the Ionized Disk of the High-Mass Protostar Orion-I

We have imaged the enigmatic radio source-I (Orion-I) in the Orion-KL nebula with the VLA at 43 GHz with 34 mas angular resolution. The continuum emission is highly elongated and is consistent with that expected from a nearly edge-on disk. The high brightness and lack of strong molecular lines from Orion-I can be used to argue against emission from dust. Collisional ionization and H-minus free-free opacity, as in Mira variables, require a central star with >10^5 Lsun, which is greater than infrared observations allow. However, if significant local heating associated with accretion occurs, lower total luminosities are possible. Alternatively, photo-ionization from an early B-type star and p+/e- bremsstrahlung can explain our observations, and Orion-I may be an example of ionized accretion disk surrounding a forming massive star. Such accretion disks may not be able to form planets efficiently.Comment: 16 pages, 1 table, 3 figure

Connecticut Transit (CTTRANSIT) Fuel Cell Transit Bus: Preliminary Evaluation Results

This report provides preliminary results from a National Renewable Energy Laboratory evaluation of a protoptye fuel cell transit bus operating at Connecticut Transit in Hartford. Included are descriptions of the planned fuel cell bus demonstration and equipment; early results and agency experience are also provided