INVESTIGATION OF EMISSION RATES OF AMMONIA, NITROUS OXIDE AND OTHER EXHAUST COMPOUNDS FROM ALTERNATIVE- FUEL VEHICLES USING A CHASSIS DYNAMOMETER

Huai, T.,Durbin, T.-D.,Rhee, S.-H.,Norbeck, J.-M. The Korean Society of Automotive Engineers 2003 International journal of automotive technology Vol.4 No.1

Exhaust emissions were characterized for a fleet of 10 alternative-fuel vehicles (AFVx) including 5 compressed natural gas (CNG) vehicles. 3 liquefied petroleum gas (LPG) vehicles and 2 85% methanol/15% California Phase 2 gasoline (M85) vehicles. In addition to the standard regulated emissions and detailed speciation of organic gas compounds, Fourier Transform Infrared Spectroscopy (FTIR) was used to measure ammonia (NH$_3$) and nitrous oxide ($N_2$O) emissions. NH$_3$, emissions averaged 0.124 g/mi for the vehicle fleet with a range from <0.004 to 0.540 g/mi. $N_2$O emissions averaged 0.022 g/mi over the vehicle fleet with range from <0.002 to 0.077 g/mi. Modal emissions showed that both NH$_3$, and $N_2$O emissions began during catalyst light-off and continued as the catalyst reached its operating temperature. $N_2$O emissions primarily were formed during the initial stages of catalyst light-off. Detailed speciation measurements showed that the principal component of the fuel was also the primary organic gas species found in the exhaust. In particular, methane, propane and methanol composed on average 93%, 79%, and 75% of the organic gas emissions, respectively, for the CNG, LPG. and M85 vehicles.

INVESTIGATION OF EMISSION RATES OF AMMONIA, NITROUS OXIDE AND OTHER EXHAUST COMPOUNDS FROM ALTERNATIVE-FUEL VEHICLES USING A CHASSIS DYNAMOMETER

T. HUAI,T. D. DURBIN,S. H. RHEE,J. M. NORBECK 한국자동차공학회 2003 International journal of automotive technology Vol.4 No.1

Exhaust emissions were characterized for a fleet of 10 alternative-fuel vehicles (AFVs) including 5 compressed natural gas (CNG) vehicles, 3 liquefied petroleum gas (LPG) vehicles and 2 85% methano1/15% Califrnia Phase 2 gasoline (M85) vehicles. In addition to the standard regulated emissions and detailed speciation of organic gas compounds. Fourier Transform Infrared Spectroscopy (FTIR) was used to measure ammonia (NH₃) and nitrous oxide (N₂O) emissions. NH₃ emissions averaged 0.124 g/mi for the vehicle fleet with a range from <0.004 to 0.540 g/mi. N₂O emissions averaged 0.022 g/mi over the vehicle fleet with range from <0.002 to 0.077 g/mi. Modal emissions showed that both NH₃ and N₂O emissions began during catalyst light-off and continued as the catalyst reached its operating temperature. N₂O emissions primarily were farmed during the initial stages of catalyst light-off. Detailed speciation measurements showed that the principal component of the fuel was also the primary organic gas species found in the exhaust. In particular, methane. propane and methanol composed on average 93%. 79%. and 75% of the organic gas emissions. respectively. for the CNG. LPG. and M85 vehicles.<br/>

Analysis of heteroepitaxial germanium on gallium arsenide grown by pulsed laser deposition

S. M. Durbin,J. P. Zheng,A. Markwitz,V. J. Kennedy,A. Pun 한국물리학회 2004 Current Applied Physics Vol.4 No.2-4

Interest in the pulsed laser deposition (PLD) technique now extends far beyond growth of multiple component oxides, the area inwhich it rst proved itself. In particular, it shows promise as a viable technique for high-quality crystalline thin lms on substrates with low thermal tolerance. In this paper, we report the PLD growth of single-crystal Ge on (10) GaAs substrates in the tem-perature range of 150550.C. In situ reection high-energy electron diraction shows the formation of a reconstructed surface afteras few as two laser pulses, corresponding to approximately 4% monolayer coverage. Transmission electron microscopy conrms heteroepitaxial growth with good quality interfaces and smooth surfaces, despite the presence of oxygen and carbon impurities.

Characterisation of polycrystalline gallium nitride grown by plasma-assisted evaporation

S. M. Durbin,V. J. Kennedy,S. I. Liem,R. J. Reeves,A. Markwitz,V. A. Christie 한국물리학회 2004 Current Applied Physics Vol.4 No.2-4

The remarkable success of GaN-based devices despite comparatively large defect densities has prompted many groups to explorepolycrystalline and amorphous GaN thin lms for various device applications. In this paper we present the results of a series of lmgrowths performed using an RF plasma assisted molecular beam epitaxy system. GaN lms were grown on quartz substrates in thetemperature range of 150650.C, and in all cases were found to be polycrystalline and largelyc-axis oriented. Rutherford back-scattering spectroscopy indicates lms have gallium-rich stoichiometry, except for those grown below 200.C. Bandedge photo-luminescence was observed at room temperature even for the lms grown at 150.C, and many lms exhibited a measurable changein resistivity under exposure to ultraviolet radiation.

MEASUREMENT OF OPERATIONAL ACTIVITY FOR NONROAD DIESEL CONSTRUCTION EQUIPMENT

T. HUAI,S.D. SHAH,T.D. DURBIN J.M. NORBECK 한국자동차공학회 2005 International journal of automotive technology Vol.6 No.4

In order to better quantify the contribution from nonroad sources to emission inventories, it is important to understand not only the emissions rates of these engines but also activity patterns that can be used to accurately portray their in-use operation. To date, however, very little information is available on the actual activity patterns of nonroad equipment. In this study, a total of 18 pieces of nonroad equipment were instrumented with collected data including intake manifold air pressure (MAP), exhaust temperature and, on a subset of vehicles, engine rpm and throttle position. The equipment included backhoes, compactors, dozers, motor graders, loaders and scrappers used in applications such as landfilling, street maintenance and general roadwork. The activity patterns varied considerably depending on the type of equipment and the application. Daily equipment operating time ranged from less than 30 minutes to more than 8 hours, with landfill equipment having the highest daily use. The number of engine starts per day ranged from 3?11 over the fleet with an average of 5 starts per day. The average percent idle time for the fleet was approximately 25% with a range from 11 to 65% for individual pieces of equipment. Duty cycles based on exhaust temperature/throttle position profiles were also developed for two graders and one dozer.

Microstructure and high temperature mechanical properties of sapphire/R-Al-O(R = Y, Gd, Er, Ho, Dy) eutectic fibers grown by micro-pulling-down method

Hasegawa, K.,Yoshikawa, A.,Durbin, S.D.,Epellbaum, B.M.,Fukuda, T.,Waku, Y. The Korea Association of Crystal Growth 1999 韓國結晶成長學會誌 Vol.9 No.4

Fiber growth of $Al_{2}O_{3}/R-Al-O$ (R = Y, Gd, Dy, Ho, Er) eutectic by the micro-pulling down method is described. The thermal stability and strength at elevated temperature of each materials is evaluated in relation to the microstructure.

MEASUREMENT OF OPERATIONAL ACTIVITY FOR NONROAD DIESEL CONSTRUCTION EQUIPMENT

HUAI T.,SHAH S. D.,DURBIN T. D.,NORBECK J. M. The Korean Society of Automotive Engineers 2005 International journal of automotive technology Vol.6 No.4

In order to better quantify the contribution from nonroad sources to emission inventories, it is important to understand not only the emissions rates of these engines but also activity patterns that can be used to accurately portray their in-use operation. To date, however, very little information is available on the actual activity patterns of nonroad equipment. In this study, a total of 18 pieces of nonroad equipment were instrumented with collected data including intake manifold air pressure (MAP), exhaust temperature and, on a subset of vehicles, engine rpm and throttle position. The equipment included backhoes, compactors, dozers, motor graders, loaders and scrappers used in applications such as landfilling, street maintenance and general roadwork. The activity patterns varied considerably depending on the type of equipment and the application. Daily equipment operating time ranged from less than 30 minutes to more than 8 hours, with landfill equipment having the highest daily use. The number of engine starts per day ranged from 3-11 lover the fleet with an average of 5 starts per day. The average percent idle time for the fleet was approximately $25\%$ with a range from 11 to $65\%$ for individual pieces of equipment. Duty cycles based on exhaust temperature/throttle position profiles were also developed for two graders and one dozer.

Analysis of silicon terahertz diffractive optics

E. D. Walsby,S. M. Durbin,D. R. S. Cumming,R. J. Blaikie 한국물리학회 2004 Current Applied Physics Vol.4 No.2-4

Simulations of silicon diractive lenses for terahertz frequencies have been performed using a Fraunhofer wave propagationmodel to show how the lens eciency can be aected by dierent fabrication defects. A general model is presented to illustrate theoperating bounds which must be adhered to when fabricating a lens using a multiple level process. From these simulations it ispossible to ascertain for a specic lens design with known processing inaccuracies what level of design complexity will gain the mostbenet. It is shown that for a 1 THz lens fabricated using an eight level process the lens eciency is reduced by less than 20% forrealistic values of etch non-uniformity, inter-level misalignment and surface roughness.

Carbon enhanced blue-violet luminescence in ZnO films grown by pulsed laser deposition

R.J. Mendelsberg,J. Kennedy,S.M. Durbin,R.J. Reeves 한국물리학회 2008 Current Applied Physics Vol.8 No.3,4

samples were all deposited onc-axis sapphire at dierent ambient oxygen pressures. They were then characterized using ellipsometry,atomic-force microscopy (AFM), photoluminescence (PL) spectroscopy, Rutherford backscattering spectroscopy (RBS), and nuclearreaction analysis (NRA).Along with the characteristic band-edge (3.36 eV) and deep level (2.3 eV) PL features, strong blue/violet emissions around 3 eV werealso observed and are generally attributed to zinc vacancies and zinc interstitials. NRA reveals carbon impurities in all samples and theintroduction of more carbon impurities enhanced the blue/violet emissions and inhibited the green luminescence. It is concluded that thecarbon impurities promote the zinc related native defects in ZnO and may also be radiative centers in the violet part of the spectrum.

Evidence for room temperature ferromagnetism in the In1-xCrxN system

R.J. Kinsey,P.A. Anderson,Z. Liu,S. Ringer,S.M. Durbin 한국물리학회 2006 Current Applied Physics Vol.6 No.3

Despite considerable research on the nitride based dilute magnetic semiconductors (DMS) there is still considerable uncertainty as tothe origin of the room temperature ferromagnetism, with clusters and precipitates suggested. We have studied chromium doped indiumnitride (In1. xCrxN) withx varying from 0.005 to 0.04 and have observed room temperature ferromagnetic behaviour in all of our lmswithx within the growing lm suggests that it is on interstitial sites. We also do not see a signicant paramagnetic component in temperaturedependent magnetisation measurements, which also suggests that any superparamagnetic behaviour due to chromium clusters is not asignicant part of the magnetic behaviour. The magnitude of the ferromagnetic signal scales with the electron concentration in the lm,rather than the chromium concentration, which may suggest that In1. xCrxN shows the electron based equivalent of the hole mediatedferromagnetism observed in Ga1. xMn xAs.