Stability of Pt near surface alloys under electrochemical conditions: a model study

2014 ◽  
Vol 16 (31) ◽  
pp. 16615-16622 ◽  
Author(s):  
Xiaoming Zhang ◽  
Shansheng Yu ◽  
Weitao Zheng ◽  
Ping Liu
Keyword(s):  
Fuel Cell ◽  
Automotive Applications ◽  
Surface Alloys ◽  
Near Surface ◽  
Model Study ◽  
The Stability

The stability is one of the key requirements for commercializing the fuel cell electrocatalysts in automotive applications.

Near-surface alloys for hydrogen fuel cell applications

2006 ◽  
Vol 111 (1-2) ◽  
pp. 52-58 ◽  
Author(s):  
Jeff Greeley ◽  
Manos Mavrikakis
Keyword(s):  
Fuel Cell ◽  
Hydrogen Fuel Cell ◽  
Hydrogen Fuel ◽  
Surface Alloys ◽  
Near Surface

scholarly journals Performance analysis of hydrogen fuel cell with two-stage turbo compressor for automotive applications

2021 ◽  
Vol 7 ◽  
pp. 2635-2646
Author(s):  
Nabeel Ahsan ◽  
Ans Al Rashid ◽  
Asad A. Zaidi ◽  
Ramsha Imran ◽  
Sikandar Abdul Qadir
Keyword(s):  
Fuel Cell ◽  
Performance Analysis ◽  
Hydrogen Fuel Cell ◽  
Automotive Applications ◽  
Hydrogen Fuel ◽  
Two Stage ◽  
Turbo Compressor

Effect of Ag-(La0.8Sr0.2)0.95MnO3 current-collecting layer on the stability of anode-supported solid oxide fuel cell

2010 ◽  
Vol 496 (1-2) ◽  
pp. 433-435 ◽  
Author(s):  
C.H. Zhao ◽  
R.Z. Liu ◽  
L. Shao ◽  
S.R. Wang ◽  
T.L. Wen
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
The Stability

scholarly journals Analysis of Urban Effects in Oklahoma City using a Dense Surface Observing Network

2016 ◽  
Vol 55 (3) ◽  
pp. 723-741 ◽  
Author(s):  
Xiao-Ming Hu ◽  
Ming Xue ◽  
Petra M. Klein ◽  
Bradley G. Illston ◽  
Sheng Chen
Keyword(s):  
Metropolitan Area ◽  
Land Surface ◽  
Critical Role ◽  
Central Business District ◽  
Temperature Inversion ◽  
Oklahoma City ◽  
Near Surface ◽  
Open Questions ◽  
The Stability ◽  
Business District

AbstractMany studies have investigated urban heat island (UHI) intensity for cities around the world, which is normally quantified as the temperature difference between urban location(s) and rural location(s). A few open questions still remain regarding the UHI, such as the spatial distribution of UHI intensity, temporal (including diurnal and seasonal) variation of UHI intensity, and the UHI formation mechanism. A dense network of atmospheric monitoring sites, known as the Oklahoma City (OKC) Micronet (OKCNET), was deployed in 2008 across the OKC metropolitan area. This study analyzes data from OKCNET in 2009 and 2010 to investigate OKC UHI at a subcity spatial scale for the first time. The UHI intensity exhibited large spatial variations over OKC. During both daytime and nighttime, the strongest UHI intensity is mostly confined around the central business district where land surface roughness is the highest in the OKC metropolitan area. These results do not support the roughness warming theory to explain the air temperature UHI in OKC. The UHI intensity of OKC increased prominently around the early evening transition (EET) and stayed at a fairly constant level throughout the night. The physical processes during the EET play a critical role in determining the nocturnal UHI intensity. The near-surface rural temperature inversion strength was a good indicator for nocturnal UHI intensity. As a consequence of the relatively weak near-surface rural inversion, the strongest nocturnal UHI in OKC was less likely to occur in summer. Other meteorological factors (e.g., wind speed and cloud) can affect the stability/depth of the nighttime boundary layer and can thus modulate nocturnal UHI intensity.

The Compliance Method for Measurement of Near Surface Residual Stresses—Analytical Background

1994 ◽  
Vol 116 (4) ◽  
pp. 550-555 ◽  
Author(s):  
M. Gremaud ◽  
W. Cheng ◽  
I. Finnie ◽  
M. B. Prime
Keyword(s):  
Numerical Simulation ◽  
Residual Stresses ◽  
Random Errors ◽  
Residual Stress Field ◽  
Near Surface ◽  
Surface Residual Stresses ◽  
Zero Shift ◽  
Stress States ◽  
The Stability ◽  
Piecewise Functions

Introducing a thin cut from the surface of a part containing residual stresses produces a change in strain on the surface. When the strains are measured as a function of the depth of the cut, residual stresses near the surface can be estimated using the compliance method. In previous work, the unknown residual stress field was represented by a series of continuous polynomials. The present paper shows that for stress states with steep gradients, superior predictions are obtained by using “overlapping piecewise functions” to represent the stresses. The stability of the method under the influence of random errors and a zero shift is demonstrated by numerical simulation.

The stability of the stratospheric ozone layer during the end-Permian eruption of the Siberian Traps

2007 ◽  
Vol 365 (1856) ◽  
pp. 1843-1866 ◽  
Author(s):  
David J Beerling ◽  
Michael Harfoot ◽  
Barry Lomax ◽  
John A Pyle
Keyword(s):  
Organic Matter ◽  
Transport Model ◽  
Stratospheric Ozone ◽  
Ultraviolet B ◽  
Large Reservoir ◽  
Near Surface ◽  
Siberian Traps ◽  
Northern Latitudes ◽  
The Stability ◽  
Mutagenic Effects

The discovery of mutated palynomorphs in end-Permian rocks led to the hypothesis that the eruption of the Siberian Traps through older organic-rich sediments synthesized and released massive quantities of organohalogens, which caused widespread O 3 depletion and allowed increased terrestrial incidence of harmful ultraviolet-B radiation (UV-B, 280–315 nm; Visscher et al . 2004 Proc. Natl Acad. Sci. USA 101 , 12 952–12 956). Here, we use an extended version of the Cambridge two-dimensional chemistry–transport model to evaluate quantitatively this possibility along with two other potential causes of O 3 loss at this time: (i) direct effects of HCl release by the Siberian Traps and (ii) the indirect release of organohalogens from dispersed organic matter. According to our simulations, CH 3 Cl released from the heating of coals alone caused comparatively minor O 3 depletion (5–20% maximum) because this mechanism fails to deliver sufficiently large amounts of Cl into the stratosphere. The unusual explosive nature of the Siberian Traps, combined with the direct release of large quantities of HCl, depleted the model O 3 layer in the high northern latitudes by 33–55%, given a main eruptive phase of less than or equal to 200 kyr. Nevertheless, O 3 depletion was most extensive when HCl release from the Siberian Traps was combined with massive CH 3 Cl release synthesized from a large reservoir of dispersed organic matter in Siberian rocks. This suite of model experiments produced column O 3 depletion of 70–85% and 55–80% in the high northern and southern latitudes, respectively, given eruption durations of 100–200 kyr. On longer eruption time scales of 400–600 kyr, corresponding O 3 depletion was 30–40% and 20–30%, respectively. Calculated year-round increases in total near-surface biologically effective (BE) UV-B radiation following these reductions in O 3 layer range from 30–60 (kJ m −2  d −1 ) BE up to 50–100 (kJ m −2  d −1 ) BE . These ranges of daily UV-B doses appear sufficient to exert mutagenic effects on plants, especially if sustained over tens of thousands of years, unlike either rising temperatures or SO 2 concentrations.

Three-component analysis of regional seismograms

1990 ◽  
Vol 80 (6B) ◽  
pp. 2032-2052 ◽  
Author(s):  
D. C. Jepsen ◽  
B. L. N. Kennett
Keyword(s):  
Free Surface ◽  
Time Window ◽  
Seismic Station ◽  
P Wave ◽  
Sh Waves ◽  
Near Surface ◽  
Source Discrimination ◽  
Decomposition Scheme ◽  
Phased Array Techniques ◽  
The Stability

Abstract Both phased array techniques for single-component sensors and vectorial analysis of three-component recordings can provide estimates of the azimuth and slowness of seismic phases. However, a combination of these approaches provides a more powerful tool to estimate the propagation characteristics of different seismic phases at regional distances. Conventional approaches to the analysis of three-component seismic records endeavor to exploit the apparent angles of propagation in horizontal and vertical planes as well as the polarization of the waves. The basic assumption is that for a given time window there is a dominant wavetype (e.g., a P wave) traveling in a particular direction arriving at the seismic station. By testing a range of characteristics of the three-component records, a set of rules can be established for classifying much of the seismogram in terms of wavetype and direction. It is, however, difficult to recognize SH waves in the presence of other wavetypes. Problems also arise when more than one signal (in either wavetype or direction) arrive in the same window. The stability and robustness of the classification scheme is much improved when records from an array of three-component sensors are combined. For a set of three-component instruments forming part of a larger array, it is possible to estimate the slowness and azimuth of arrivals from the main array and then extract the relative proportions of the current P-, SV-, and SH-wave contributions to the seismogram. This form of wavetype decomposition depends on a model of near-surface propagation. A convenient choice for hard-rock sites is to include just the effect of the free surface, which generates a frequency-independent operation on the three-component seismograms and which is not very sensitive to surface velocities. This approach generates good estimates of the character of the S wavefield, because the phase distortion of SV induced by the free surface can be removed. The method has been successfully applied to regional seismograms recorded at the medium aperture Warramunga array in northern Australia, and the two small arrays NORESS and ARCESS in Norway, which were designed for studies of regional phases. The new wavefield decomposition scheme provides results in which the relative proportions of P, SV, and SH waves as a function of time can be compared without the distortion imposed by free surface amplification. Such information can provide a useful adjunct to existing measures of signal character used in source discrimination.

Component Power Sizing and Limits of Operation for Proton Exchange Membrane (PEM) Fuel Cell/Battery Hybrid Automotive Applications

2001 ◽  
Author(s):  
Daisie D. Boettner ◽  
Gino Paganelli ◽  
Yann G. Guezennec ◽  
Giorgio Rizzoni ◽  
Michael J. Moran
Keyword(s):  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Control Strategies ◽  
Cell System ◽  
Proton Exchange ◽  
System Model ◽  
Automotive Applications ◽  
Fuel Cell System ◽  
Vehicle Performance ◽  
Exchange Membrane

Abstract This paper describes use of a Proton Exchange Membrane (PEM) fuel cell system model for automotive applications in a fuel cell system/battery hybrid configuration. The fuel cell system model has been integrated into a vehicle performance simulator that determines fuel economy and allows consideration of control strategies. The simulator is used to explore relevant regions of the fuel cell-powered hybrid electric vehicle design space by conducting simulations using two simple supervisory-control strategies: thermostatic control and proportional control. During the simulations power provided by the battery and fuel cell system and operational limits on battery state of charge and fuel cell system current density are varied while maintaining minimum component sizing to meet vehicle performance criteria. Analysis of results from these simulations provides component power sizing and limits of operation suitable for development of a more advanced supervisory vehicle control strategy for a fuel cell vehicle.

Sign in / Sign up

Export Citation Format

Share Document