Moessbauer spectroscopy of Mg(0.9)Fe(0.1)SiO3 perovskite

NASA Technical Reports Server (NTRS)

Jeanloz, Raymond; O'Neill, Bridget; Pasternak, Moshe P.; Taylor, R. D.; Bohlen, Steven R.

1992-01-01

Ambient pressure Moessbauer spectra of Mg(0.9)Fe-57(0.1)SiO3 perovskite synthesized at pressure-temperature conditions of about 50 GPa and 1700 K show that the iron is entirely high-spin Fe(2+) and appears to be primarily located in the octahedral site within the crystal structure. We observe broad Moessbauer lines, suggesting a distribution of electric-field gradients caused by disorder associated with the Fe ions. Also, the perovskite exhibits magnetic ordering at temperatures lower than 5 K, implying that there is a magnetic contribution to the absolute ('third-law') entropy of this phase.

Sulfidation of Co/Al[sub 2]O[sub 3] and CoMo/Al[sub 2]O[sub 3] catalysts studied by Moessbauer emission spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Craje, M.W.J.; Kraan, A.M. van der; Beer, V.H.J. de

1993-10-01

The structure of hydrodesulfurization catalysts is relevant to many industries. The sulfidation of uncalcined and calcined alumina-supported cobalt and cobalt-molybdenum catalysts was systematically studied by means of in situ Moessbauer emission spectroscopy (MES) at room temperature. The spectra obtained during the stepwise sulfidation of the uncalcined catalysts clearly resemble those observed for carbon-supported ones. Hence, the interpretation of the spectra of the alumina-supported catalysts is based on the conclusions drawn from the MES studies of the carbon-supported catalysts, which are less complex because Co ions do not diffuse into the support. It is demonstrated that not only in sulfided CoMo/Al[submore » 2]O[sub 3], but also in sulfided Co/Al[sub 2]O[sub 3], catalysts Co-sulfide species with a [open quotes]Co-Mo-S[close quotes]-type quadrupole splitting can be formed. It is concluded that the Co-sulfide species formed in sulfided Co/Al[sub 2]O[sub 3] and CoMo/Al[sub 2]O[sub 3] catalysts are essentially the same, only the particle size and ordering of the Co-sulfide species may differ, as in the case of Co/C and CoMo/C catalysts. The function of the Mo, which is present as MoS[sub 2], is merely to stabilize very small Co-sulfide particles, which in the limit contain only one single Co atom. Furthermore, it turns out that the value of the electric quadrupole splitting (Q.S. value) of the Co-sulfide phase in the sulfided catalysts depends on the sulfiding temperature and Co content. This observation leads to the conclusion that large Q.S. values point to the presence of very small Co-sulfide entities or particles (the lower limit being [open quotes]particles[close quotes] containing only one Co atom, such as proposed in the [open quotes]Co-Mo-S[close quotes] model), whereas small Q.S. values point to the presence of large Co-sulfide particles (the upper limit being crystalline Co[sub 9]S[sub 8]). 28 refs., 7 figs., 6 tabs.« less

The 2010 ILSO-ISRU Field Test at Mauna Kea, Hawaii: Results from the Miniaturised Mossbauer Spectrometers Mimos II and Mimos IIA

NASA Technical Reports Server (NTRS)

Klingelhoefer, G.; Morris, R. V.; Blumers, M.; Bernhardt, B.; Graff, T.

2011-01-01

For the advanced Moessbauer instrument MIMOS IIA, the new detector technologies and electronic components increase sensitivity and performance significantly. In combination with the high energy resolution of the SDD it is possible to perform X-ray fluorescence analysis simultaneously to Moessbauer spectroscopy. In addition to the Fe-mineralogy, information on the sample's elemental composition will be gathered. The ISRU 2010 field campaign demonstrated that in-situ Moessbauer spectroscopy is an effective tool for both science and feedstock exploration and process monitoring. Engineering tests showed that a compact nickel metal hydride battery provided sufficient power for over 12 hr of continuous operation for the MIMOS instruments.

Reflectivity (visible and near IR), Moessbauer, static magnetic, and X ray diffraction properties of aluminum-substituted hematites

NASA Technical Reports Server (NTRS)

Morris, Richard V.; Schulze, Darrell G.; Lauer, Howard V., Jr.; Agresti, David G.; Shelfer, Tad D.

1992-01-01

The effect of substituting iron by aluminum in polymorphs of Fe2O3 and FeOOH on their reflectivity characteristics was investigated by comparing data on visible and NIR reflectivities and on static magnetic, XRD, and Moessbauer properties for a family of aluminum-substituted hematites alpha-(Fe,Al)2O3, with compositions where the values of the Al/(Al+Fe) ratio were up to 0.61. Samples were prepared by oxidation of magnetite, dehydroxylation of goethite, and direct precipitation. The analytical methods used for obtaining diffuse reflectivity spectra (350-2200 nm), Moessbauer spectra, and static magnetic data are those described by Morris et al. (1989).

The Microscopic Magnetic Properties of W-type Hexaferrite Powder Prepared by A Sol-Gel Route

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jotania, Rajshree; Chauhan, Chetna; Sharma, Pooja

2010-12-01

Magnetic particles of W-type barium-calcium hexaferrite (BaCa{sub 2}Fe{sub 16}O{sub 27}) have been synthesized using a Stearic acid gel route. The gel precursors were dried at 100 deg. C for 2 hrs and then calcinated at 650 deg. C, 750 deg. C, 850 deg. C and 950 deg. C for 4 hrs in a furnace and slowly cooled to room temperature in order to obtain barium-calcium hexaferrite particles. The microscopic magnetic properties of prepared samples studying using Moessbauer spectroscopy. Moessbauer spectra of all samples were recorded at room temperature. Mossbauer parameters like Isomer shift, Quadruple splitting etc. were calculated with respectmore » to iron foil. Barium calcium hexaferrite samples heated at 650 deg. C, 750 deg. C, 850 deg. C show relaxation type Moessbauer spectra along with paramagnetic doublet. The intensity of paramagnetic doublet increases with temperature confirm the presence of ferrous ions in the samples, where as sample calcinated at 950 deg. C confirm the presence of ferrimagnetic phase with partial super paramagnetic nature of prepared hexaferrite sample.« less

Moessbauer effect: Study of disordered magnetic systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, Xiao Sha.

1989-01-01

This dissertation describes Moessbauer spectroscopy studies of two chemically disordered binary, crystalline alloys having the composition A{sub 1-x}B{sub x}. Both systems are random 3d Heisenberg ferromagnets. In each case both A and B atoms carry a magnetic moment. The first study concerns a Moessbauer absorber experiment on Fe{sub 1-x} V{sub x}, in which the disorder in the critical region is of the annealed random exchange type. To eliminate the effect of concentration inhomogeneity, the measurement of the critical exponent {beta} was done on the alloy with x = 0.125, where dT{sub C}/dx = 0, yielding {beta} = 0.362(8) over themore » reduced temperature range 1.4 {times} 10{sup {minus}3} < t < 4.88 {times} 10{sup {minus}1}. This result confirms the theoretical prediction that the annealed disorder is irrelevant to critical behavior in this case. As expected the critical exponent {beta} is consistent with the expectation for the 3d Heisenberg model as well as the measured exponent of pure Fe. The second study involves a Moessbauer source experiment on {sup 57} CoPd{sub 0.80}Co{sub 0.20}, in which disorder is of the quenched random exchange type perturbed by a very weak random anisotropy interaction. The critical exponent {beta} deduced over the range 1 {times} 10{sup {minus}2} < t < 2 {times} 10{sup {minus}1} is 0.385(20), and is consistent with the theoretical prediction for quenched disordered 3d Heisenberg systems: the disorder is irrelevant to the critical behavior. However, because of the restricted range of reduced temperature, the result is insufficiently asymptotic to serve as a conclusive test of the theory. Outside the critical region the distribution of Fe{sup 57} hyperfine field in Pd{sub 0.80}Co{sub 0.20} is observed to have an anomalous temperature dependence characterized by a linear increase in the width of the field distribution for T/T{sub C} {ge} 0.6.« less

Moessbauer Close-Up

NASA Technical Reports Server (NTRS)

2004-01-01

This close-up image of the Mars Exploration Rover Spirit's instrument deployment device, or 'arm,' shows the donut-shaped plate on the Moessbauer spectrometer. This image makes it easy to recognize the imprint left by the instrument in the martian soil at a location called 'Peak' on sol 43 (February 16, 2004). This image was taken by the rover's panoramic camera on sol 39 (February 11, 2004).

Hematite at Meridiani Planum and Gusev Crater as identified by the Moessbauer Spectrometer MIMOS II

NASA Technical Reports Server (NTRS)

Klingelhoefer, G.; Morris, R. V.; Rodionov, D.; Schroeder, C.; de Souza, P. A.; Yen, A.; Renz, F.; Wdowiak, T.

2006-01-01

The Moessbauer (MB) spectrometers on the MER rovers Opportunity and Spirit, which landed on Mars in January 2004, have identified the iron-containing mineral hematite (a-Fe2O3) at both landing sites. On Earth, hematite can occur either by itself or with other iron oxides as massive deposits, in veins , and as particles dispersed through a silicate or other matrix material. Hematite particle size can range from nanophase (superparamagnetic) to multidomain and particle shape ranges from equant to acicular to platy. Fine-grained hematite is red in color and is a pigmenting agent. Coarse-grained hematite can be spectrally neutral (gray) at visible wavelengths. Substitutional impurities, particularly Al, are common in hematite. Chemically pure, coarse-grained, and well-crystalline hematite has a magnetic transition (the Morin transition) at 260 K. Moessbauer spectra, recorded as a function of temperature, provide a way to characterize Martian hematite with respect to some of the physical and chemical characteristics. At Meridiani Planum besides the iron-sulfate mineral jarosite also the Fe-oxide hematite has been identified by the Moessbauer spectrometer, mainly in three distinct types of reservoir: - outcrop matrix material dominated by the mineral jarosite in the MB spectrum, certain basaltic soils, and mm-sized spherules dubbed blueberries. Moessbauer spectra of each reservoir yield a distinct set of hyperfine parameters for hematite, suggesting different degrees of crystallinity and particle size. The hematite found by MB instrument MIMOS II in the outcrop material shows the Morin transition at relatively high temperatures (ca. 250 K) which is an indication of pure and well-crystallized hematite. The source of the hematite in the Blueberries as identified by Moessbauer spectroscopy, and also by MiniTES, is not known. These spherules, covering nearly the whole landing site area (Eagle crater, plains, Endurance crater), may be concretions formed in the outcrop involving aqueous processes. They are dispersed throughout the hematite containing jarositic outcrop material. According to Moessbauer analysis the dominating iron-bearing mineral in the spherules is hematite, and jarosite not been detected so far in significant amounts. But there are some places with hematite showing characteristics different from the hematite described above: (1) the soil at B023_HematiteSlope_Hema2 has some blueberries, but the MB did not seem to intercept any. The temperature dependence of its MB parameters are different from those of blueberries. (2) B049_RasberryNewton_Filling shows a unique Hm MB signature, as well as (3) B051_RealSharksTooth_Enamel1.

Chemostratigraphy and Fe Mineralogy of the Victoria Crater Duck Bay Section: Opportunity APXS and Moessbauer Results

NASA Technical Reports Server (NTRS)

Mittlefehldt, D. W.; Schroeder, C.; Gellert, R.; Klingelhoefer, G.; Jolliff, B. L.; Morris, R. V.

2008-01-01

Meridiani Planum is a vast plain of approximately horizontally bedded sedimentary rocks composed of mixed and reworked basaltic and evaporitic sands containing secondary, diagenetic minerals [e.g., 1-5]. Because bedding planes are subparallel to topography, investigation of contiguous stratigraphy requires examining exposures in impact craters. Early in the mission (sols 130-317), Opportunity was commanded to do detailed study of exposed outcrops in Endurance crater, including the contiguous Karatepe section at the point of ingress. Just over 1000 sols later and roughly 7 km to the south, the rover is being commanded to do a similar study of the Duck Bay section of Victoria crater. Here we report on the preliminary results from the Alpha Particle X-ray Spectrometer (APXS) and Moessbauer instruments.

The Miniaturized Moessbauer Spectrometers MIMOS II on MER: Four Years of Operation - A Summary

NASA Technical Reports Server (NTRS)

Fleischer, I.; Klingelhoefer, G.; Morris, R. V.; Rodionov, D.; Blumers, M.; Bernhardt, B.; Schroeder, C.; Ming, D. W.; Yen, A. S.; Cohen, B. A.;

Quantifying the Complete Mineral Assemblages in Rocks of GUSEV Crater, Mars

NASA Technical Reports Server (NTRS)

McSween, H. Y.; Ruff, S. W.; Morris, R. V.; Gellert, R.

2007-01-01

Determining the complete mineralogy of Mars rocks by remote sensing has remained a challenge, because of inherent limitations in the minerals that can be detected and uncertainties in spectral modeling. A subset of the igneous rocks of Gusev crater provide a unique opportunity to determine modal mineralogy, because of limited alteration and the analytical capabilities of the Athena instrument package. Here we estimate the absolute (wt. %) abundances of Fe-bearing minerals from Moessbauer spectra (previously reported only as "areas for component subspectra"), and compare these results to the normative mineralogy calculated from APXS elemental analyses. We also test our preferred mineralogy by comparison of Mini-TES spectra with synthetic thermal emission spectra.

Inter particle interaction in Ni{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4} prepared by self combustion method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sudheesh, V. D.; Vinesh, A.; Lakshmi, N.

Ni{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4} has been prepared by self combustion method and studied using X-ray diffraction, Moessbauer spectroscopy and DC magnetization techniques. X-ray diffractogram shows highly crystalline nano sized sample with no impurity phases. The room temperature Moessbauer and magnetization measurements show the co-existence of superparamagnetic and ferrimagnetic particles in the sample. The presence of inter particle interaction is confirmed from the {delta}M(H) curve at 20K. The dependence of magnetic moment below blocking temperature in the field cooling curve indicates that the inter particle interaction is weak in the as prepared sample.

Moessbauer Mineralogy on the Moon: The Lunar Regolith

NASA Technical Reports Server (NTRS)

Morris, Richard V.; Korotev, Randy L..; Shelfer, Tad D.; Klingelhoefer, Goestar

1997-01-01

A first-order requirement for spacecraft missions that land on solid planetary objects is instrumentation for mineralogical analyses. For purposes of providing diagnostic information about naturally-occurring materials, the element iron is particularly important because it is abundant and multivalent. Knowledge of the oxidation state of iron and its distribution among iron-bearing mineralogies tightly constrains the types of materials present and provides information about formation and modification (weathering) processes. Because Moessbauer spectroscopy is sensitive to both the valence of iron and its local chemical environment, the technique is unique in providing information about both the relative abundance of iron-bearing phases and oxidation state of the iron. The Moessbauer mineralogy of lunar regolith samples (primarily soils from the Apollo 16 and 17 missions to the Moon) were measured in the laboratory to demonstrate the strength of the technique for in situ mineralogical exploration of the Moon. The regolith samples were modeled as mixtures of five iron-bearing phases: olivine, pyroxene, glass, ilmenite, and metal. Based on differences in relative proportions of iron associated with these phases, volcanic ash regolith can be distinguished from impact-derived regolith, impact-derived soils of different geologic affinity (e.g., highlands, maria) can be distinguished on the basis of their constituent minerals, and soil maturity can be estimated. The total resonant absorption area of the Moessbauer spectrum can be used to estimate total FeO concentrations.

Moessbauer and Electron Microprobe Studies of Density Separates of Martian Nakhlite Mil03346: Implications for Interpretation of Moessbauer Spectra Acquired by the Mars Exploration Rovers

NASA Technical Reports Server (NTRS)

Morris, R. V.; McKay, G. A.; Agresti, D. G.; Li, Loan

2008-01-01

Martian meteorite MIL03346 is described as an augite-rich cumulate rock with approx.80%, approx.3%, and approx.21% modal phase proportions of augite (CPX), olivine and glassy mesostasis, respectively, and is classified as a nakhlite [1]. The Mossbauer spectrum for whole rock (WR) MIL 03346 is unusual for Martian meteorites in that it has a distinct magnetite subspectrum (7% subspectral area) [2]. The meteorite also has products of pre-terrestrial aqueous alteration ("iddingsite") that is associated primarily with the basaltic glass and olivine. The Mossbauer spectrometers on the Mars Exploration Rovers have measured the Fe oxidation state and the Fe mineralogical composition of rocks and soils on the planet s surface since their landing in Gusev Crater and Meridiani Planum in January, 2004 [3,4]. The MIL 03346 meteorite provides an opportunity to "ground truth" or refine Fe phase identifications. This is particularly the case for the so-called "nanophase ferric oxide" (npOx) component. NpOx is a generic name for a ferric rich product of oxidative alteration. On Earth, where we can take samples apart and study individual phases, examples of npOx include ferrihydrite, schwertmannite, akagaaneite, and superparamagnetic (small particle) goethite and hematite. It is also possible for ferric iron to be associated to some unknown extent with igneous phases like pyroxene. We report here an electron microprobe (EMPA) and Moessbauer (MB) study of density separates of MIL 03346. The same separates were used for isotopic studies by [5]. Experimental techniques are described by [6,7].

Hematite at Meridiani Planum and Gusev Crater as identified by the Moessbauer Spectrometer MIMOS II

NASA Astrophysics Data System (ADS)

Klingelhoefer, G.; Morris, R. V.; Rodionov, D.; Schroeder, C.; de Souza, P. A.; Yen, A.; Renz, F.; Wdowiak, T.

2004-12-01

The Moessbauer (MB) spectrometers on the MER rovers Opportunity and Spirit, which landed on Mars in January 2004, have identified the iron-containing mineral hematite (a-Fe2O3) at both landing sites. On Earth, hematite can occur either by itself or with other iron oxides as massive deposits, in veins , and as particles dispersed through a silicate or other matrix material. Hematite particle size can range from nanophase (superparamagnetic) to multidomain and particle shape ranges from equant to acicular to platy. Fine-grained hematite is red in color and is a pigmenting agent. Coarse-grained hematite can be spectrally neutral (gray) at visible wavelengths. Substitutional impurities, particularly Al, are common in hematite. Chemically pure, coarse-grained, and well-crystalline hematite has a magnetic transition (the Morin transition) at ~260 K. Moessbauer spectra, recorded as a function of temperature, provide a way to characterize Martian hematite with respect to some of the physical and chemical characteristics. At Meridiani Planum besides the iron-sulfate mineral jarosite also the Fe-oxide hematite has been identified by the Moessbauer spectrometer, mainly in three distinct types of reservoir: - outcrop matrix material dominated by the mineral jarosite in the MB spectrum, certain basaltic soils, and mm-sized spherules dubbed blueberries. Moessbauer spectra of each reservoir yield a distinct set of hyperfine parameters for hematite, suggesting different degrees of crystallinity and particle size. The hematite found by MB instrument MIMOS II in the outcrop material shows the Morin transition at relatively high temperatures (ca. 250 K) which is an indication of pure and well-crystallized hematite. The source of the hematite in the `Blueberries' as identified by Moessbauer spectroscopy, and also by MiniTES, is not known. These spherules, covering nearly the whole landing site area (Eagle crater, plains, Endurance crater), may be concretions formed in the outcrop involving aqueous processes. They are dispersed throughout the hematite containing jarositic outcrop material. According to Moessbauer analysis the dominating iron-bearing mineral in the spherules is hematite, and jarosite not been detected so far in significant amounts. But there are some places with hematite showing characteristics different from the hematite described above: (1) the soil at B023-HematiteSlope-Hema2 has some blueberries, but the MB did not seem to intercept any. The temperature dependence of its MB parameteres are different from those of blueberries. (2) B049-RasberryNewton-Filling shows a unique Hm MB signature, as well as (3) B051-RealSharksTooth-Enamel1. At Gusev Crater no widespread occurrence of hematite has been detected on the Gusev plains, although minor amounts of hematite were detected in an alteration rind on the rock Mazatzal at the rim of Bonneville crater. At the Columbia Hills, however, the MB instrument did find hematite in significant amounts in highly altered rocks, showing at the same time a significant decrease in the amount of olivine compared to typical basaltic rocks at Gusev crater.

Coordination of Fe, Ga and Ge in high pressure glasses by Moessbauer, Raman and X-ray absorption spectroscopy, and geological implications

NASA Technical Reports Server (NTRS)

Fleet, M. E.; Henderson, G. S.; Herzberg, C. T.; Crozier, E. D.; Osborne, M. D.; Scarfe, C. M.

1984-01-01

For some time, it has been recognized that the structure of silicate liquids has a great bearing on such magma properties as viscosity, diffusivity, and thermal expansion and on the extrapolation of thermodynamic quantities outside of the experimentally measurable range. In this connection it is vital to know if pressure imposes changes in melt structure similar to the pressure-induced reconstructive transformations in crystals. In the present study on 1 bar and high pressure glasses, an investigation is conducted regarding the coordination of Fe(3+) in Fe silicate glasses by Moessbauer spectroscopy. Raman spectroscopy is employed to explore the coordinations of Ge(4+) in GeO2 glasses and of Ga(3+) in NaGa silicate glasses, while the coordination of Ga(3+) in NaGaSiO4 glasses is studied with the aid of methods of X-ray absorption spectroscopy.

Coordination of Fe, Ga and Ge in high pressure glasses by Moessbauer, Raman and X-ray absorption spectroscopy, and geological implications

NASA Astrophysics Data System (ADS)

Fleet, M. E.; Herzberg, C. T.; Henderson, G. S.; Crozier, E. D.; Osborne, M. D.; Scarfe, C. M.

1984-07-01

For some time, it has been recognized that the structure of silicate liquids has a great bearing on such magma properties as viscosity, diffusivity, and thermal expansion and on the extrapolation of thermodynamic quantities outside of the experimentally measurable range. In this connection it is vital to know if pressure imposes changes in melt structure similar to the pressure-induced reconstructive transformations in crystals. In the present study on 1 bar and high pressure glasses, an investigation is conducted regarding the coordination of Fe(3+) in Fe silicate glasses by Moessbauer spectroscopy. Raman spectroscopy is employed to explore the coordinations of Ge(4+) in GeO2 glasses and of Ga(3+) in NaGa silicate glasses, while the coordination of Ga(3+) in NaGaSiO4 glasses is studied with the aid of methods of X-ray absorption spectroscopy.

Moessbauer spectra of olivine-rich achondrites - Evidence for preterrestrial redox reactions

NASA Technical Reports Server (NTRS)

Burns, R. G.; Martinez, S. L.

1991-01-01

Moessbauer spectral measurements at 4.2 K were made on several ureilites and the two shergottites found in Antarctica, as well as two ureilite falls, three SNC meteorite falls, and two finds in order to distinguish products of preterrestrial redox reactions from phases formed during oxidative weathering on the earth. The spectra indicated that several ureilites contain major proportions of metallic iron, much of which resulted from preterrestrial carbon-induced reduction of ferrous iron in the outermost 10-100 microns of olivine grains in contact with carbonaceous material in the ureilites. The cryptocrystalline nature of these Fe inclusions in olivine renders the metal extremely vulnerable to aerial oxidation, even in ureilites collected as falls. It is inferred that the nanophase ferric oxides or oxyhydroxides identified in Brachina and Lafayette were produced by terrestrial weather of olivines before the meteorites were found. The absence of goethite in two olivine-bearing Antarctic shergottites suggests that the 2 percent ferric iron determined in their Moessbauer spectra also originated from oxidation on Mars.

Synthesis and Properties of Ortho-Nitro-Fe Complex

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mishra, A.; Mishra, Niyati; Sharma, R.

2011-07-15

Ortho-Nitro-Fe complex (Transition metal complex) has synthesized by chemical route method and properties of made complex has characterized by X-Ray diffraction (XRD), Moessbauer spectroscopy, Fourier transformation infra-red spectroscopy (FTIR) and X-Ray photoelectron spectroscopy (XPS). XRD analysis shows that sample is crystalline in nature and having particle size in the range of few nano meters. Moessbauer spectroscopy at room temperature shows the oxidation state of Iron (central metal ion) after complaxasion. FTIR spectra of the complex confirms the coordination of metal ion with ligand.

Spectral chemistry of green glass-bearing 15426 regolith

NASA Technical Reports Server (NTRS)

Burns, R. G.; Dyar, M. D.

1983-01-01

The detection of appreciable concentrations of ferric iron in a synthetic green glass equilibrated at an oxygen fugacity of 10 to the -11th atm prompted a Moessbauer spectral study of pristine emerald-green glass spherules carefully handpicked from regolith sample 15426. No Fe(3+) ions were detected in this lunar sample or in a synthetic green glass simulant equilibrated at fO2 = 10 to the -14th atm, suggesting that the green glass clods in rock 15426 formed under conditions of correspondingly low oxygen fugacities. The Moessbauer spectra indicated the presence of olivine crystallites in the lunar emerald green glass spherules. Measurements of homogeneous and partially devitrified synthetic silicate glasses revealed that significant changes of coordination environment about Fe(2+) ions in the glass structure occur during crystallization of olivine crystals from the melt.

Effect of cycled combustion ageing on a cordierite burner plate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garcia, Eugenio; Gancedo, J. Ramon; Gracia, Mercedes, E-mail: rocgracia@iqfr.csic.es

2010-11-15

A combination of {sup 57}Fe-Moessbauer spectroscopy and X-ray Powder Diffraction analysis has been employed to study modifications in chemical and mechanical stability occurring in a cordierite burner aged under combustion conditions which simulate the working of domestic boilers. Moessbauer study shows that Fe is distributed into the structural sites of the cordierite lattice as Fe{sup 2+} and Fe{sup 3+} ions located mostly at octahedral sites. Ferric oxide impurities, mainly hematite, are also present in the starting cordierite material accounting for {approx_equal}40% of the total iron phases. From Moessbauer and X-ray diffraction data it can be deduced that, under the combustionmore » conditions used, new crystalline phases were formed, some of the substitutional Fe{sup 3+} ions existing in the cordierite lattice were reduced to Fe{sup 2+}, and ferric oxides underwent a sintering process which results in hematite with higher particle size. All these findings were detected in the burner zone located in the proximity of the flame and were related to possible chemical reactions which might explain the observed deterioration of the burner material. Research Highlights: {yields}Depth profile analyses used as a probe to understand changes in refractory structure. {yields}All changes take place in the uppermost surface of the burner, close to the flame. {yields}Reduction to Fe{sup 2+} of substitutional Fe{sup 3+} ions and partial cordierite decomposition. {yields}Heating-cooling cycling induces a sintering of the existing iron oxide particles. {yields}Chemical changes can explain the alterations observed in the material microstructure.« less

Map of Moessbauer Placement

NASA Technical Reports Server (NTRS)

2004-01-01

This elevation map of a soil target called 'Peak' was created from images taken by the microscopic imager located on the Mars Exploration Rover Spirit's instrument deployment device or 'arm.' The image reveals the various high and low points of this spot of soil after the Moessbauer spectrometer, another instrument on the rover's arm, was gently placed down on it. The blue areas are farthest away from the instrument; the red areas are closest. The variation in distance between blue and red areas is only 2 millimeters, or .08 of an inch. The images were acquired on sol 39 (February 11, 2004).

Moessbauer spectrometer based on UNO-4096-90 accumulator and Elektronika D3-28 microcomputer for simultaneous recording of four spectra

DOE Office of Scientific and Technical Information (OSTI.GOV)

Romanov, E.S.; Ivoilov, N.G.

A buffer memory unit and an interface for the UNO-4096-90 accumulator with an Elektronika D3-28 microcomputer are described that allow simultaneous recording of four Moessbauer spectra with zero dead time. For complete elimination of dead time, the pulses from each detector are fed to two buffer counters units, which operate alternately in the write and interrogate modes. This organization of the buffer memory also completely eliminates the effect of the sensors on one another. The use of these circuits does not require any modifications of the computer or accumulator.

Moessbauer Characterization of Magnetite/Polyaniline Magnetic Nanocomposite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rodriguez, Anselmo F. R.; Faria, Fernando S. E. D. V.; Lopez, Jorge L.

2010-12-02

Aniline surface coated Fe{sub 3}O{sub 4} nanoparticles have been successfully synthesized by UV irradiation varying the time and the acid media (HCl, HNO{sub 3}, or H{sub 2}SO{sub 4}). The synthesized material represents a promising platform for application in nerve regeneration. XRD patterns are consistent with the crystalline structure of magnetite. Nevertheless, for UV irradiation times longer than 2 h, extra XRD lines reveal the presence of goethite. The mean crystallite size of uncoated particles is estimated to be 25.4 nm, meanwhile that size is reduced to 19.9 nm for the UV irradiated sample in HCl medium for 4 h. Moessbauermore » spectra of uncoated nanoparticles reveal the occurrence of thermal relaxation at room temperature, while the 77 K-Moessbauer spectrum suggests the occurrence of electron localization effects similar to that expected in bulk magnetite. The Mossbauer spectra of UV irradiated sample in HCl medium during 4 h, confirms the presence of the goethite phase. For this sample, the thermal relaxation is more evident, since the room temperature spectrum shows larger spectral area for the nonmagnetic component due to the smaller crystallite size. Meanwhile, the 77 K-Moessbauer spectrum suggests the absence of the electron localization effect above 77 K.« less

An East to West Mineralogical Trend in Mars Exploration Rover Spirit Moessbauer Spectra of Home Plate

NASA Technical Reports Server (NTRS)

Schroder, C.; Di, K.; Morris, R. V.; Klingelhofer, G.; Li, R.

2008-01-01

Home Plate is a light-toned plateau approx.90 m in diameter within the Inner Basin of the Columbia Hills in Gusev crater on Mars. It is the most extensive exposure of layered bedrock encountered by Spirit to date, and it is composed of clastic rocks of moderately altered alkali basalt composition, enriched in some highly volatile elements. Textural observations suggest an explosive origin and geochemical observations favor volcanism, probably a hydrovolcanic explosion [1]. Since it first arrived at Home Plate on sol 744, Spirit has circumnavigated the plateau (Fig. 1) and is now, since sol 1410, resting at its Winter Haven 3 location at the north end of Home Plate. Results: The MER Moessbauer spectrometers determine Fe oxidation states, identify Fe-bearing mineral phases and quantify the distribution of Fe among oxidation states and mineral phases [2]. Moessbauer spectra of Home Plate bedrock were obtained in five different locations from nine different targets (Fig. 1): Barnhill Ace, Posey Manager, and James Cool Papa Bell Stars at the northwest side of Home Plate; Pesapallo, June Emerson, and Elizabeth Emery on the east side; Texas Chili on the south side; Pecan Pie on the west side; and Chanute on the north side.

Bricks in historical buildings of Toledo City: characterisation and restoration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lopez-Arce, Paula; Garcia-Guinea, Javier; Gracia, Mercedes

2003-01-15

Two different types of ancient bricks (12th to 14th centuries) collected from historical buildings of Toledo (Spain) were characterised by optical microscopy, scanning electron microscopy/energy-dispersive X-ray spectrometers (SEM/EDS), electron probe microanalysis (EM), X-ray diffraction (XRD), differential thermal analysis (DTA) and {sup 57}Fe-Moessbauer spectroscopy. Physical properties such as water absorption and suction, porosity, density and compression strength were also determined. Several minerals found in the brick matrix, such as garnet, let us infer raw material sources; calcite, dolomite, illite and neoformed gehlenite and diopside phases, on temperature reached in firing; secondary calcite, on first cooling scenarios; and manganese micronodules, on latemore » pollution environments. XRD and DTA of original and refired samples supply information about firing temperatures. Additional data on firing conditions and type of the original clay are provided by the Moessbauer study. Physical properties of both types of bricks were compared and correlated with raw materials and fabric and firing technology employed. The physicochemical characterisation of these bricks provides valuable data for restoration purposes to formulate new specific bricks using neighbouring raw materials.« less

Innovative instrumentation for mineralogical and elemental analyses of solid extraterrestrial surfaces: The Backscatter Moessbauer Spectrometer/X Ray Fluorescence analyzer (BaMS/XRF)

NASA Technical Reports Server (NTRS)

Shelfer, T. D.; Morris, Richard V.; Nguyen, T.; Agresti, D. G.; Wills, E. L.

1994-01-01

We have developed a four-detector research-grade backscatter Moessbauer spectrometer (BaMS) instrument with low resolution x-ray fluorescence analysis (XRF) capability. A flight-qualified instrument based on this design would be suitable for use on missions to the surfaces of solid solar-system objects (Moon, Mars, asteroids, etc.). Target specifications for the flight instrument are as follows: mass less than 500 g; volumes less than 300 cu cm; and power less than 2 W. The BaMS/XRF instrument would provide data on the oxidation state of iron and its distribution among iron-bearing mineralogies and elemental composition information. This data is a primary concern for the characterization of extraterrestrial surface materials.

Synthetic (Hydrothermal) Hematite-Rich Mars-Analog Spherules from Acid-Sulfate Brines: Implications for Formation and Diagenesis of Hematite Spherules in Outcrops at Meridiani Planum, Mars

NASA Technical Reports Server (NTRS)

Golden, D. C.; Ming, D. W.; Morris, R. V.; Graff, T. G.

2008-01-01

The Thermal Emission Spectrometer (TES) onboard the Mars Global Surveyor (MGS) orbiter discovered a large area at Meridiani Planum (MP) covered with the Fe-oxide hematite (alpha-Fe2O3) [1,2]. This discovery and favorable landing site characteristics led to selection of MP as the landing site for the Opportunity Mars Exploration Rover (MER) [3]. The Athena science payload onboard the Opportunity rover identified hematite-rich spherules (mean spherule diameter approx.4.2+/-0.8 mm) embedded in S-rich outcrop rock and also as lag deposits of whole and broken spherules [4,5,6,7,8,9]. Although the chemical and mineralogical compositions of spherules are not fully constrained, Moessbauer spectrometer (MB) Miniature Thermal Emission Spectrometer (Mini-TES) and chemical analyses from the Alpha Particle X-Ray Spectrometer (APXS) are consistent with a hematite mineralogical composition and an oxide bulk chemical composition consisting of Fe2O3. MGS-TES, also provides an important constraint that emission from the hematite-rich spherules is dominated by emission along the crystallographic c-axis [1,2,10,11]. The formation of hematite-rich spherules with similar chemical, mineralogical, morphological, and crystallographic properties to the MP spherules is rare on Earth, to date, only two natural analogs have been proposed; one from Utah (Navaho Concretions) and the other from Mauna Kea, Hawaii [12,13]. In this study, we synthesized in the laboratory hematite-rich spherules using conditions that may have existed on Early Mars [14] and compared their properties to those for MP hematite spherules of Mars and the analog spherules from Utah and Mauna Kea in order to assess their relative merit as MP hematite spherule analogs. Such comparisons yield clues to the formation pathway for MP spherules.

Compositional Analysis of Martian Soil: Synergism of APEX and MECA Experiments on MPS 2001

NASA Technical Reports Server (NTRS)

Arvidson, R.; Marshall, J.

1999-01-01

The APEX (ATHENA Precursor Experiment) payload for the Mars 2001 mission will analyze soil and dust with a multispectral panoramic imager and an emission spectrometer on a mast on the lander, a Moessbauer spectrometer on the lander robotic arm (RA), and APXS measurements on the Marie Curie rover. These analytical methods will provide data on elemental abundances and mineralogy. The MECA payload on the lander will apply microscopy, AFM, wet chemistry, adhesive substrates, and electrometry to determine the shape and size of particles in the soil and dust, the presence of toxic substances, and electrostatic, magnetic, and hardness qualities of particles. The two experiments will complement one another through several interactions: (1) The panoramic imager provides the geological setting in which both APEX and MECA samples are acquired, (2) The RA provides samples to MECA from the surface and subsurface and will permit APEX analytical tools access to materials below the immediate surface, (3) Comparisons can be made between elemental analyses of the Moessbauer, IR, APXS on APEX and the wet chemistry of MECA which will define trace elements (ionic species in solution) and soil redox potential and conductivity. (4) APEX bulk compositional measurements will place MECA trace measurements in context, and similarly, MECA microscopy will provide particle size data that may correlate with compositional differences determined by the APEX instruments. Additionally, lithic fragments viewed by the MECA microscope station should correlate with mineral/rock species inferred by APEX data, (5) If APEX instruments detect quartz for example, the scratch plates of the MECA microscope stage will define if a mineral of this hardness is registered during abrasion tests. This is by no means an exhaustive list of potential interactions, but it is clear that both the sheer number of analytical techniques and their complementarity should provide an analytically powerful capability for both planetary and HEDS communities.

Compositional Analysis of Martian Soil: Synergism of APEX and MECA Experiments on MPS 2001

NASA Technical Reports Server (NTRS)

Arvidson, R.; Marshall, J.

1999-01-01

The APEX (ATHENA Precursor Experiment) payload for the Mars 2001 mission will analyze soil and dust with a multispectral panoramic imager and an emission spectrometer on a mast on the lander, a Moessbauer spectrometer on the lander robotic arm (RA), and APXS measurements on the Marie Curie rover. These analytical methods will provide data on elemental abundances and mineralogy. The MECA payload on the lander will apply microscopy, AFM, wet chemistry, adhesive substrates, and electrometry to determine the shape and size of particles in the soil and dust, the presence of toxic substances, and electrostatic, magnetic, and hardness qualities of particles. The two experiments will complement one another through several interactions: (1) The panoramic imager provides the geological setting in which both APEX and MECA samples are acquired, (2) The RA provides samples to MECA from the surface and subsurface and will permit APEX analytical tools access to materials below the inunediate surface, (3) Comparisons can be made between elemental analyses of the Moessbauer, IR, APXS on APEX and the wet chemistry of MECA which will define trace elements (ionic species in solution) and soil redox potential and conductivity. (4) APEX bulk compositional measurements will place MECA trace measurements in context, and similarly, MECA microscopy will provide particle size data that may correlate with compositional differences determined by the APEX instruments. Additionally, lithic fragments viewed by the NMCA microscope station should correlate with mineral/rock species inferred by APEX data, (5) If APEX instruments detect quartz for example, the scratch plates of the N4ECA microscope stage will define if a mineral of this hardness is registered during abrasion tests. This is by no means an exhaustive list of potential interactions, but it is clear that both the sheer number of analytical techniques and their complementarity should provide an analytically powerful capability for both planetary and BEDS communities.

Iron-oxide Aerogel and Xerogel Catalyst Formulations: Characterization by 57Fe Mössbauer and XAFS Spectroscopies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huggins, F.; Bali, S; Huffman, G

2010-01-01

Iron in various iron-oxide aerogel and xerogel catalyst formulations ({ge}85% Fe{sub 2}O{sub 3}; {le}10% K, Co, Cu, or Pd) developed for possible use in Fischer-Tropsch synthesis (FTS) or the water-gas-shift (WGS) reaction has been examined by {sup 57}Fe Moessbauer spectroscopy. The seventeen samples consisted of both as-prepared and calcined aerogels and xerogels and their products after use as catalysts for FTS or the WGS reaction. Complementary XAFS spectra were obtained on the occurrence of the secondary elements in some of the same materials. A broad, slightly asymmetric, two-peak Moessbauer spectrum was obtained from the different as-prepared and calcined catalyst formulationsmore » in the majority of cases. Such spectra could only be satisfactorily fit with three quadrupole doublet components, but no systematic trends in the isomer shift and quadrupole splitting parameters and area ratios of the individual components could be discerned that reflected variations in the composition or preparation of the aerogel or xerogel materials. However, significant reductions were noted in the Moessbauer effective thickness (recoilless absorption effect per unit mass of iron) parameter, {chi}{sub eff}/g, determined at room temperature, for aerogels and xerogels compared to bulk iron oxides, reflecting the openness and lack of rigidity of the aerogel and xerogel structures. Moessbauer measurements for two aerogels over the range from 15 to 292 K confirmed the greatly diminished nature of this parameter at room temperature. Major increases in the effective thickness parameter were observed when the open structure of the aerogel or xerogel collapsed during calcination resulting in the formation of iron oxides (hematite, spinel ferrite). Similar structural changes were indicated by increases in this parameter after use of iron-oxide aerogels as catalysts for FTS or the WGS reaction, during which the iron-oxide aerogel was converted to a mixture of nonstoichiometric magnetite and the Haegg carbide, {chi}-Fe{sub 5}C{sub 2}, or nonstoichiometric magnetite, respectively.« less

YPdSn and YPd{sub 2}Sn: Structure, {sup 89}Y solid state NMR and {sup 119}Sn Moessbauer spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoeting, Christoph; Eckert, Hellmut; Langer, Thorsten

2012-06-15

The stannides YPdSn and YPd{sub 2}Sn were synthesized by high-frequency melting of the elements in sealed tantalum tubes. Both structures were refined on the basis of single crystal X-ray diffractometer data: TiNiSi type, Pnma, a=715.4(1), b=458.8(1), c=789.1(1) pm, wR2=0.0461, 510 F{sup 2} values, 20 variables for YPdSn and MnCu{sub 2}Al type, Fm3 Macron m, a=671.44(8), wR2=0.0740, 55 F{sup 2} values, 5 parameters for YPd{sub 2}Sn. The yttrium atoms in the new stannide YPdSn are coordinated by two tilted Pd{sub 3}Sn{sub 3} hexagons (ordered AlB{sub 2} superstructure). In the Heusler phase YPd{sub 2}Sn each yttrium atom has octahedral tin coordination andmore » additionally eight palladium neighbors. The cubic site symmetry of yttrium is reflected in the {sup 119}Sn Moessbauer spectrum which shows no quadrupole splitting. In contrast, YPdSn shows a single signal at {delta}=1.82(1) mm/s subjected to quadrupole splitting of {Delta}E{sub Q}=0.93(1) mm/s. Both compounds have been characterized by high-resolution {sup 89}Y solid state NMR spectroscopy, which indicates the presence of strong Knight shifts. The spectrum of YPd{sub 2}Sn is characterized by an unusually large linewidth, suggesting the presence of a Knight shift distribution reflecting local disordering effects. The range of {sup 89}Y Knight shifts of several binary and ternary intermetallic yttrium compounds is briefly discussed. - Graphical abstract: YPdSn and YPd{sub 2}Sn: Structure, {sup 89}Y solid state NMR and {sup 119}Sn Moessbauer spectroscopy. Highlights: Black-Right-Pointing-Pointer Synthesis and structure of ternary stannides YPdSn and YPd{sub 2}Sn. Black-Right-Pointing-Pointer {sup 119}Sn Moessbauer spectroscopic investigation of YPdSn and YPd{sub 2}Sn. Black-Right-Pointing-Pointer {sup 89}Y solid state NMR of intermetallics.« less

Moessbauer spectroscopy and scanning electron microscopy of the Murchison meteorite

NASA Technical Reports Server (NTRS)

Brown, Christopher L.; Oliver, Frederick W.; Hammond, Ernest C., Jr.

1989-01-01

Meteorites provide a wealth of information about the solar system's formation, since they have similar building blocks as the Earth's crust but have been virtually unaltered since their formation. Some stony meteorites contain minerals and silicate inclusions, called chondrules, in the matrix. Utilizing Moessbauer spectroscopy, we identified minerals in the Murchison meteorite, a carbonaceous chondritic meteorite, by the gamma ray resonance lines observed. Absorption patterns of the spectra were found due to the minerals olivine and phyllosilicate. We used a scanning electron microscope to describe the structure of the chondrules in the Murchison meteorite. The chondrules were found to be deformed due to weathering of the meteorite. Diameters varied in size from 0.2 to 0.5 mm. Further enhancement of the microscopic imagery using a digital image processor was used to describe the physical characteristics of the inclusions.

Fe-Bearing Phases Identified by the Moessbauer Spectrometers on the Mars Exploration Rovers: An Overview

NASA Technical Reports Server (NTRS)

Morris, R. V.; Klingelhoefer, G.; Rodionov, D.; Yen, A.; Gellert, R.

2006-01-01

The twin Mars Exploration Rovers Spirit and Opportunity have explored the martian surface at Gusev Crater (GC) and Meridiani Planum (MP), respectively, for about two Earth years. The Moessbauer (MB) spectrometers on both rovers have analyzed an aggregate of 200 surface targets and have returned to Earth information on the oxidation state of iron, the mineralogical composition of Febearing phases, and the distribution of Fe among oxidation states and phases at the two landing sites [1-7]. To date, 15 component subspectra (10 doublets and 5 sextets) have been identified and most have been assigned to mineralogical compositions. Two subspectra are assigned to phases (jarosite and goethite) that are marker minerals for aqueous processes because they contain hydroxide anion in their structures. In this paper, we give an overview of the Febearing phases identified and their distributions at Gusev crater and Meridiani Planum.

Fe-Bearing Phases Indentified by the Moessbauer Spectrometers on the Mars Exploration Rovers: An Overview

NASA Technical Reports Server (NTRS)

Morris, R. V.; Klingelhoefer, G.; Ming, D. W.; Schroeder, C.; Rodionov, D.; Yen, A.; Gellert, R.

2006-01-01

The twin Mars Exploration Rovers Spirit and Opportunity have explored the martian surface at Gusev Crater (GC) and Meridiani Planum (MP), respectively, for about two Earth years. The Moessbauer (MB) spectrometers on both rovers have analyzed an aggregate of approx.200 surface targets and have returned to Earth information on the oxidation state of iron, the mineralogical composition of Fe-bearing phases, and the distribution of Fe among oxidation states and phases at the two landing sites [1-7]. To date, 15 component subspectra (10 doublets and 5 sextets) have been identified and most have been assigned to mineralogical compositions. Two subspectra are assigned to phases (jarosite and goethite) that are marker minerals for aqueous processes because they contain hydroxide anion in their structures. In this paper, we give an overview of the Febearing phases identified and their distributions at Gusev crater and Meridiani Planum.

Moessbauer studies in Zn(2+)0.3 Mn(2+)0.7 Mn(3+) (2-y) Fe(3+) (2-y) O4

NASA Technical Reports Server (NTRS)

Gupta, R. G.; Mendiratta, R. G.; Escue, W. T.

1975-01-01

The Mossbauer effect has proven to be effective in the study of nuclear hyperfine interactions. Ferrite systems having the formula (Zn(2+)0.3)(Mn(2+)0.7)(Mn(3+)y)(Fe(3+)2-y)(O4) were prepared and studied. These systems can be interpreted as mangacese-doped zinc and a part of iron ions. A systematic study of these systems is presented to promote an understanding of their microstructure for which various theories were proposed.

Moessbauer spectroscopy analysis of {sup 57}Fe-doped YBaCo{sub 4}O{sub 7+{delta}}: Effects of oxygen intercalation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsipis, E.V.; Department of Ceramics and Glass Engineering, CICECO, University of Aveiro, 3810-193 Aveiro; Waerenborgh, J.C.

2009-03-15

Moessbauer spectroscopy of layered YBaCo{sub 3.96}Fe{sub 0.04}O{sub 7+{delta}} ({delta}=0.02 and 0.80), where 1% cobalt is substituted with {sup 57}Fe isotope, revealed no evidence of charge ordering at 4-293 K. The predominant state of iron cations was found trivalent, irrespective of their coordination and oxygen stoichiometry variations determined by thermogravimetric analysis. The extremely slow kinetics of isothermal oxidation at 598 K in air, and the changes of Fe{sup 3+} fractions in the alternating triangular and Kagome layers in oxidized YBaCo{sub 3.96}Fe{sub 0.04}O{sub 7.80}, may suggest that oxygen intercalation is accompanied with a substantial structural reconstruction stagnated due to sluggish cation diffusion.more » Decreasing temperature below 75-80 K leads to gradual freezing of the iron magnetic moments in inverse correlation with the content of extra oxygen. The formation of metal-oxygen octahedra and resultant structural distortions extend the temperature range where the paramagnetic and frozen states co-exist, down to 45-50 K. - Graphical abstract: Moessbauer spectroscopy of layered YBaCo{sub 3.96}Fe{sub 0.04}O{sub 7+{delta}} ({delta}=0.02 and 0.80), with 1% {sup 57}Fe isotope substituted for cobalt, revealed no evidence of charge ordering at 4-293 K. The predominant state of iron cations was found trivalent, irrespective of their coordination and oxygen stoichiometry variations determined by thermogravimetric analysis. Decreasing temperature below 75-80 K leads to gradual freezing of the iron magnetic moments in inverse correlation with the content of extra oxygen extending the temperature range where the paramagnetic and frozen states co-exist down to 45-50 K.« less

Mineralogy at Gusev Crater and Meridiani Planum from the Moessbauer Spectrometers on the Mars Exploration Rovers

NASA Technical Reports Server (NTRS)

Morris, Richard V.; Klingelhoefer, Goestar

2006-01-01

The Moessbauer spectrometers on the twin MER rovers Spirit and Opportunity have provided significant new information on the distribution of iron among its oxidation states, the identification of the mineralogical composition of iron-bearing phases, and the distribution of iron among those phases for rock and soil at Gusev Crater and Meridiani Planum. The plains of Gusev Crater are dominated by olivine-bearing basalt (approximately Fo(60)) and Fe(3+)/Fe(total)=0.1 - 0.5. The oxide mineral generally present is magnetite. In contrast, initial results for the Columbia Hills are consistent with the presence of hematite and a ferrous iron phase, possibly pyroxene. Gusev spectra also have a ferric doublet (not jarosite) that is tentatively associated with nano-phase ferric oxide. A wider diversity of material is present at Meridiani Planum. Significantly, jarosite-bearing outcrop is present throughout the region, with good exposures in impact craters such as Eagle and Endurance (Fe(3+)/Fe (total) approx. 0.9). The Moessbauer identification of jarosite (a hydroxyl-bearing sulfate mineral) is evidence for aqueous, acid-sulfate processes on Mars. Hematite is observed within the outcrop matrix and in the spheroidal particles (Blueberries) found within the outcrop and as a surface lag. An isolated rock (Bounce Rock) was the only sample at either landing site whose iron-bearing phase was dominated by pyroxene. The basaltic sand in the central portion of Eagle crater, in the intercrater plains, and between slabs of outcrop at both Eagle and Endurance craters is olivine-bearing basalt. The widespread occurrence of olivine-bearing basalt at both MER landing sites implies that physical, rather than chemical, weathering processes dominate at the surface of contemporary Mars.

Emerging surface characterization techniques for carbon steel corrosion: a critical brief review.

PubMed

Dwivedi, D; Lepkova, K; Becker, T

2017-03-01

Carbon steel is a preferred construction material in many industrial and domestic applications, including oil and gas pipelines, where corrosion mitigation using film-forming corrosion inhibitor formulations is a widely accepted method. This review identifies surface analytical techniques that are considered suitable for analysis of thin films at metallic substrates, but are yet to be applied to analysis of carbon steel surfaces in corrosive media or treated with corrosion inhibitors. The reviewed methods include time of flight-secondary ion mass spectrometry, X-ray absorption spectroscopy methods, particle-induced X-ray emission, Rutherford backscatter spectroscopy, Auger electron spectroscopy, electron probe microanalysis, near-edge X-ray absorption fine structure spectroscopy, X-ray photoemission electron microscopy, low-energy electron diffraction, small-angle neutron scattering and neutron reflectometry, and conversion electron Moessbauer spectrometry. Advantages and limitations of the analytical methods in thin-film surface investigations are discussed. Technical parameters of nominated analytical methods are provided to assist in the selection of suitable methods for analysis of metallic substrates deposited with surface films. The challenges associated with the applications of the emerging analytical methods in corrosion science are also addressed.

Emerging surface characterization techniques for carbon steel corrosion: a critical brief review

NASA Astrophysics Data System (ADS)

Dwivedi, D.; Lepkova, K.; Becker, T.

2017-03-01

Carbon steel is a preferred construction material in many industrial and domestic applications, including oil and gas pipelines, where corrosion mitigation using film-forming corrosion inhibitor formulations is a widely accepted method. This review identifies surface analytical techniques that are considered suitable for analysis of thin films at metallic substrates, but are yet to be applied to analysis of carbon steel surfaces in corrosive media or treated with corrosion inhibitors. The reviewed methods include time of flight-secondary ion mass spectrometry, X-ray absorption spectroscopy methods, particle-induced X-ray emission, Rutherford backscatter spectroscopy, Auger electron spectroscopy, electron probe microanalysis, near-edge X-ray absorption fine structure spectroscopy, X-ray photoemission electron microscopy, low-energy electron diffraction, small-angle neutron scattering and neutron reflectometry, and conversion electron Moessbauer spectrometry. Advantages and limitations of the analytical methods in thin-film surface investigations are discussed. Technical parameters of nominated analytical methods are provided to assist in the selection of suitable methods for analysis of metallic substrates deposited with surface films. The challenges associated with the applications of the emerging analytical methods in corrosion science are also addressed.

Emerging surface characterization techniques for carbon steel corrosion: a critical brief review

PubMed Central

Dwivedi, D.; Becker, T.

2017-01-01

Carbon steel is a preferred construction material in many industrial and domestic applications, including oil and gas pipelines, where corrosion mitigation using film-forming corrosion inhibitor formulations is a widely accepted method. This review identifies surface analytical techniques that are considered suitable for analysis of thin films at metallic substrates, but are yet to be applied to analysis of carbon steel surfaces in corrosive media or treated with corrosion inhibitors. The reviewed methods include time of flight-secondary ion mass spectrometry, X-ray absorption spectroscopy methods, particle-induced X-ray emission, Rutherford backscatter spectroscopy, Auger electron spectroscopy, electron probe microanalysis, near-edge X-ray absorption fine structure spectroscopy, X-ray photoemission electron microscopy, low-energy electron diffraction, small-angle neutron scattering and neutron reflectometry, and conversion electron Moessbauer spectrometry. Advantages and limitations of the analytical methods in thin-film surface investigations are discussed. Technical parameters of nominated analytical methods are provided to assist in the selection of suitable methods for analysis of metallic substrates deposited with surface films. The challenges associated with the applications of the emerging analytical methods in corrosion science are also addressed. PMID:28413351

Lunar sample analysis

NASA Technical Reports Server (NTRS)

Housley, R. M.

1978-01-01

Flameless atomic abosrption, X-ray photoemission spectroscopy, ferromagnetic resonance, scanning electron microscopy, and Moessbauer spectroscopy were used to investigate the evolution of the lunar regolith, the transport of volatile trace metals, and the surface composition of lunar samples. The development of a model for lunar volcanic eruptions is also discussed.

Development of the Fast Scintillation Detector with Programmable High Voltage Adjustment Suitable for Moessbauer Spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prochazka, R.; Frydrych, J.; Pechousek, J.

2010-07-13

This work is focused on a development of a compact fast scintillation detector suitable for Moessbauer spectroscopy (low energy X-ray/{gamma}-ray detection) where high counting rates are inevitable. Optimization of this part was necessary for a reliable function, better time resolution and to avoid a detector pulses pile-up effect. The pile-up effect decreases the measurement performance, significantly depends on the source activity and also on the pulse duration. Our new detection unit includes a fast scintillation crystal YAP:Ce, an R6095 photomultiplier tube, a high voltage power supply socket C9028-01 assembly, an AD5252 digital potentiometer with an I2C interface and an AD8000more » ultra fast operation preamplifier. The main advantages of this solution lie in a short pulse duration (less than 200 ns), stable operation for high activities, programmable gain of the high voltage supply and compact design in the aluminum housing.« less

Abundance and Speciation of Water and Sulfate at Gusev Crater and Meridiani Planum

NASA Technical Reports Server (NTRS)

Ming, D. W.; Clark, B. C.; Klingelhoefer, G.; Gellert, R.; Rodionov, D.; Schroeder, C.; deSouza, P.; Yen, A.

2005-01-01

A major science goal of the Mars Exploration Rover (MER) mission is to search for evidence of water activity, and direct mineralogical evidence for aqueous activity has been reported for Meridiani Planum in the form of the iron sulfate hydroxide mineral jarosite and at Gusev crater in the form of goethite. The Spirit and Opportunity rovers have each collected 110+ Moessbauer (MB) and 75+ Alpha Particle X-Ray Spectrometer (APXS) spectra from Gusev crater and Meridiani Planum [1 - 4]. In this abstract, we use mineralogical and elemental data, primarily from the Moessbauer and APXS instruments, to infer the speciation and estimate the abundance of sulfate and water (as either the H2O molecule or the hydroxyl anion) at Gusev crater and Meridiani Planum. Throughout the abstract, we adopt a format for mineral formulas that shows water explicitly rather than the usual practice of structure-based formulas (e.g., for goethite we write Fe2O3xH2O instead of FeOOH).

Mineralogical diversity (spectral reflectance and Moessbauer data) in compositionally similar impact melt rocks from Manicouagan Crater, Canada

NASA Technical Reports Server (NTRS)

Morris, R. V.; Bell, J. F., III; Golden, D. C.; Lauer, H. V., Jr.

1993-01-01

Meteoritic impacts under oxidizing surface conditions occur on both earth and Mars. Oxidative alteration of impact melt sheets is reported at several terrestrial impact structures including Manicouagan, West Clearwater Lake, and the Ries Basin. A number of studies have advocated that a significant fraction of Martian soil may consist of erosional products of oxidatively altered impact melt sheets. If so, the signature of the Fe-bearing mineralogies formed by the process may be present in visible and near infrared reflectivity data for the Martian surface. Of concern is what mineral assemblages form in impact melt sheets produced under oxidizing conditions and what their spectral signatures are. Spectral and Moessbauer data for 19 powder samples of impact melt rock from Manicouagan Crater are reported. Results show for naturally occurring materials that composite hematite-pyroxene bands have minima in the 910-nm region. Thus many of the anomalous Phobos-2 spectra, characterized by a shallow band minimum in the near-IR whose position varies between approximately 850 and 1000 nm, can be explained by assemblages whose endmembers (hematite and pyroxene) are accepted to be present on Mars. Furthermore, results show that a mineralogically diverse suite of rocks can be generated at essentially constant composition, which implies that variations in Martian surface mineralogy do not necessarily imply variations in chemical composition.

'Bounce' and Shergotty Share Common Ground

NASA Technical Reports Server (NTRS)

2004-01-01

This illustration compares the spectrum of 'Bounce,' a rock at Meridiani Planum, to that of a martian meteorite found on Earth called Shergotty. Bounce's spectrum, and thus mineral composition, is unique to the rocks studied so far at Merdiani Planum and Gusev Crater, the landings sites of the Mars Exploration Rovers Opportunity and Spirit. However, the results here indicate that Bounce is not a one-of-a-kind rock, but shares origins with Shergotty. Shergotty landed in India in 1865. Bounce's spectra were taken on sol 67 by Opportunity's Moessbauer spectrometer.

Magnetic Properties and Moessbauer Spectra of Several Iron(III) Dicarboxylic Acid Complexes.

DTIC Science & Technology

1980-10-01

model CS-202 Displex Cryogenic refrigerator with a model APD-E temperature controller manufactured by Air Products and Chemicals , Inc ., Allentown, Pa...coupled tL a special, helium gas filled shroud, Model DMX-20, supplied by Air Products and Chemicals , Inc . Infrared spectra were obtained on a Beckman IR

The Incredible Diversity of Fe-bearing Phases at Gusev Crater, Mars, According to the Mars Exploration Rover Moessbauer Spectrometer

NASA Technical Reports Server (NTRS)

Morris, R. V.; Klingelhoefer, G.; Schroeder, C.; Rodionov, D. S.; Ming, D. W.; Yen, A.

2006-01-01

The Mars Exploration Rover (MER) Spirit landed on the plains of Gusev Crater on 4 January 2004. One primary scientific objective for the mission is to characterize the mineralogical and elemental composition of surface materials, searching for evidence of water and clues for assessing past and current climates and their suitability for life [1]. The role of the Moessbauer (MB) spectrometer on Spirit is to provide quantitative information about the distribution of Fe among its oxidation and coordination states, identification of Fe-bearing phases, and relative distribution of Fe among those phases. The speciation and distribution of Fe in Martian rock and soil constrains the primary rock types, redox conditions under which primary minerals crystallized, the extent of alteration and weathering, the type of alteration and weathering products, and the processes and environmental conditions for alteration and weathering. In this abstract, we discuss the incredible diversity of Fe-bearing phases detected by Spirit s MB instrument during its first 540 sols of exploration at Gusev crater [2,3].

First X-Ray Diffraction Results from Mars Science Laboratory: Mineralogy of Rocknest Aeolian Bedform at Gale Crater

NASA Technical Reports Server (NTRS)

Bish, D. L.; Blake, D. F.; Vaniman, D. T.; Chipera, S. J.; Sarrazin, P.; Morris, R. V.; Ming, D. W.; Treiman, A. H.; Downs, R. T.; Morrison, S. M.;

The Influence of Abrasion on Martian Dust Grains: Evidence from a Study of Antigorite Grains

NASA Technical Reports Server (NTRS)

Bishop, Janice L.; Drief, Ahmed; Dyar, M. Darby

2003-01-01

Grinding was shown to greatly affect the structure and a number of properties of antigorite grains in a study by Drief and Nieto. Grinding is likely to influence the structure of most clay mineral grains and has been shown recently to influence the structure of kaolinite. The antigorite structure includes curved waves of layered silicate as shown by D dony et al.. Our study was performed in order to characterize in detail changes in the mineral grains resulting from grinding and to assess the influence of physical processes on clay minerals on the surface of Mars. This project includes a combination of SEM, reflectance spectroscopy and Moessbauer spectroscopy.

Nuclear Bragg scattering studies in [sup 57]Fe with synchrotron radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haustein, P.E.

1993-01-01

Studies of nuclear Bragg x-ray scattering of synchrotron radiation, using crystals of [alpha]-[sup 57]Fe[sub 2]O[sub 3], have been carried out at the NSLS at Brookhaven National Laboratory and at the Cornell University CHESS facility. These studies have demonstrated that nuclear resonance states can be used to produce filtered x-ray beams which have extremely narrow bandwidth, small angular divergence and unique polarization and temporal properties. this combination of characteristics, unobtainable with radioactive sources, makes synchrotron-based Moessbauer spectroscopy feasible and is an important complement to existing methods. A review of the experimental methodology is presented. As well as come suggestions for fullermore » exploitation of this new technique.« less

Nuclear Bragg scattering studies in {sup 57}Fe with synchrotron radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haustein, P.E.

1993-03-01

Studies of nuclear Bragg x-ray scattering of synchrotron radiation, using crystals of {alpha}-{sup 57}Fe{sub 2}O{sub 3}, have been carried out at the NSLS at Brookhaven National Laboratory and at the Cornell University CHESS facility. These studies have demonstrated that nuclear resonance states can be used to produce filtered x-ray beams which have extremely narrow bandwidth, small angular divergence and unique polarization and temporal properties. this combination of characteristics, unobtainable with radioactive sources, makes synchrotron-based Moessbauer spectroscopy feasible and is an important complement to existing methods. A review of the experimental methodology is presented. As well as come suggestions for fullermore » exploitation of this new technique.« less

On previous and present investigations of resonance gamma-ray interaction with nuclei at the Institute of Theoretical and Experimental Physics (ITEP, Moscow)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davydov, A. V.

A brief survey of theoretical and experimental work that is devoted to studying the resonance absorption and scattering of gamma rays by nuclei and which was initiated at the Institute of Theoretical and Experimental Physics (ITEP, Moscow) in the 1950s and has been continued to date is given. Investigations of various versions of interaction in beta decay, magnetic-field-perturbed angular distributions of resonantly scattered gamma rays, the problem of the Moessbauer gamma resonance of long-lived isomeric states of nuclei, and the resonance scattering of annihilation photons by nuclei are described.

What We Might Know About Gusev Crater if the Mars Exploration Rover Spirit Mission were Coupled with a Mars Sample Return Mission

NASA Technical Reports Server (NTRS)

Morris, Richard V.

2008-01-01

The science instruments on the Mars Exploration Rover (MER) Spirit have provided an enormous amount of chemical and mineralogical data during more than 1450 sols of exploration at Gusev crater. The Moessbauer (MB) instrument identified 10 Fe-bearing phases at Gusev Crater: olivine, pyroxene, ilmenite, chromite, and magnetite as primary igneous phases and nanophase ferric oxide (npOx), goethite, hematite, a ferric sulfate, and pyrite/marcusite as secondary phases. The Miniature Thermal Emission Spectrometer (Mini-TES) identified some of these Fe-bearing phases (olivine and pyroxene), non- Fe-bearing phases (e.g., feldspar), and an amorphous high-SiO2 phase near Home Plate. Chemical data from the Alpha Particle X-Ray Spectrometer (APXS) provided the framework for rock classification, chemical weathering/alteration, and mineralogical constraints. APXS-based mineralogical constraints include normative calculations (with Fe(3+)/FeT from MB), elemental associations, and stoichiometry (e.g., 90% SiO2 implicates opalline silica). If Spirit had cached a set of representative samples and if those samples were returned to the Earth for laboratory analysis, what value is added by Mars Sample return (MSR) over and above the mineralogical and chemical data provided by MER?

MSATT Workshop on Innovative Instrumentation for the In Situ Study of Atmosphere-Surface Interactions on Mars

NASA Technical Reports Server (NTRS)

Fegley, Bruce, Jr. (Editor); Waenke, Heinrich (Editor)

1992-01-01

Papers accepted for the Mars Surface and Atmosphere Through Time (MSATT) Workshop on Innovative Instruments for the In Situ Study of Atmosphere-Surface Interaction of Mars, 8-9 Oct. 1992 in Mainz, Germany are included. Topics covered include: a backscatter Moessbauer spectrometer (BaMS) for use on Mars; database of proposed payloads and instruments for SEI missions; determination of martian soil mineralogy and water content using the Thermal Analyzer for Planetary Soils (TAPS); in situ identification of the martian surface material and its interaction with the martian atmosphere using DTA/GC; mass spectrometer-pyrolysis experiment for atmospheric and soil sample analysis on the surface of Mars; and optical luminescence spectroscopy as a probe of the surface mineralogy of Mars.

Iron hydrides formation in interstellar clouds

NASA Astrophysics Data System (ADS)

Bar-Nun, A.; Pasternak, M.; Barrett, P. H.

1980-07-01

A recent Moessbauer study with Fe-57 in a solid hydrogen or hydrogen-argon matrix demonstrated the formation of an iron hydride molecule (FeH2) at 2.5-5 K. Following this and other studies, the possible existence of iron hydride molecules in interstellar clouds is proposed. In clouds, the iron hydrides FeH and FeH2 would be formed only on grains, by encounters of H atoms or H2 molecules with Fe atoms which are adsorbed on the grains. The other transition metals, Sc, Ti, V, Cr, Mn, Co, N, Cd and also Cu and Ca form hydrides of the type M-H, which could be responsible, at least in part, for the depletion of these metals in clouds.

Santorini, Another Meteorite on Mars and Third of a Kind

NASA Technical Reports Server (NTRS)

Schroeder, C.; Ashley, J. W.; Chapman, M. G.; Cohen, B. A.; Farrand, W. H.; Fleischer, I.; Gellert, R.; Herkenhoff, K. E.; Johnson, J. R.; Jolliff, B. L.;

Effects of Sterilization on the Physico-Chemical Properties of Natural Sediments From the Oak Ridge Reservation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bank, T.L.; Kukkadapu, R.K.; Madden, A.S.

2009-04-29

Batch U(VI) sorption/reduction experiments were completed on sterilized and non-sterilized sediment samples to elucidate biological and geochemical reduction mechanisms. Results from X-ray absorption near-edge structure (XANES) spectroscopy revealed that {gamma}-sterilized sediments were actually better sorbents of U(VI), despite the absence of any measurable biological activity. These results indicate that {gamma}-irradiation induced significant physico-chemical changes in the sediment which is contrary to numerous other studies identifying {gamma}-sterilization as an effective and minimally invasive technique. To identify the extent and method of alteration of the soil as a result of {gamma}-sterilization, untreated soil samples, physically separated size fractions, and chemically extracted fractionsmore » of the soil were analyzed pre- and post-sterilization. The effects of sterilization on mineralogy, pH, natural organic matter (NOM), cation exchange capacity (CEC), and iron oxidation state were determined. Results indicated that major mineralogy of the clay and whole sediment samples was unchanged. Sediment pH decreased only slightly with {gamma}-irradiation; however, irradiation produced a significant decrease in CEC of the untreated sediments and affected both the organic and inorganic fractions. Moessbauer spectra of non-sterile and {gamma}-sterilized sediments measured more reduced iron present in {gamma}-sterilized sediments compared to non-sterile samples. Our results suggest that sterilization by {gamma}-irradiation induced iron reduction that may have increased the sorption and/or reduction of U(VI) onto these sediments. However, Moessbauer and batch sorption data are somewhat contradictory, the former indicates that the iron oxide or iron hydroxide minerals are more significantly reduced while the later indicates that reduced clay minerals account for greater sorption of U(VI).« less

Effects of gamma-sterilization on the physicochemical properties of natural sediments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bank, Tracy L; Madden, Andrew; Baldwin, Mark E

2008-06-01

Batch U(VI) sorption/reduction experiments were completed on sterilized and non-sterilized sediment samples to elucidate biological and geochemical reduction mechanisms. Results from X-ray absorption near-edge structure (XANES) spectroscopy revealed that {gamma}-sterilized sediments were actually better sorbents of U(VI), despite the absence of any measurable biological activity. These results indicate that {gamma}-irradiation induced significant physico-chemical changes in the sediment which is contrary to numerous other studies identifying {gamma}-sterilization as an effective and minimally invasive technique. To identify the extent and method of alteration of the soil as a result of {gamma}-sterilization, untreated soil samples, physically separated size fractions, and chemically extracted fractionsmore » of the soil were analyzed pre- and post-sterilization. The effects of sterilization on mineralogy, pH, natural organic matter (NOM), cation exchange capacity (CEC), and iron oxidation state were determined. Results indicated that major mineralogy of the clay and whole sediment samples was unchanged. Sediment pH decreased only slightly with {gamma}-irradiation; however, irradiation produced a significant decrease in CEC of the untreated sediments and affected both the organic and inorganic fractions. Moessbauer spectra of non-sterile and {gamma}-sterilized sediments measured more reduced iron present in {gamma}-sterilized sediments compared to non-sterile samples. Our results suggest that sterilization by {gamma}-irradiation induced iron reduction that may have increased the sorption and/or reduction of U(VI) onto these sediments. However, Moessbauer and batch sorption data are somewhat contradictory, the former indicates that the iron oxide or iron hydroxide minerals are more significantly reduced while the later indicates that reduced clay minerals account for greater sorption of U(VI).« less

'Berries' on the Ground 2 (3-D)

NASA Technical Reports Server (NTRS)

2004-01-01

This is the 3-D anaglyph showing a microscopic image taken of soil featuring round, blueberry-shaped rock formations on the crater floor at Meridiani Planum, Mars. This image was taken on the 13th day of the Mars Exploration Rover Opportunity's journey, before the Moessbauer spectrometer, an instrument located on the rover's instrument deployment device, or 'arm,' was pressed down to take measurements. The area in this image is approximately 3 centimeters (1.2 inches) across.

Ripples in The Soil

NASA Technical Reports Server (NTRS)

2004-01-01

This is a three-dimensional stereo anaglyph of an image taken by the front navigation camera onboard the Mars Exploration Rover Spirit, showing an interesting patch of rippled soil. Spirit took this image on sol 37 (Feb. 9, 2004) after completing the longest drive ever made by a rover on another planet - 21.2 meters (69.6 feet). On sol 38 scientists plan to investigate this interesting location with the microscopic imager and Moessbauer spectrometer on Spirit's instrument deployment device.

Sn 1-x VxOy thin films deposited by pulsed laser ablation for gas sensing devices

NASA Astrophysics Data System (ADS)

Duhalde, Stella; Vignolo, M. F.; Quintana, G.; Mercader, R.; Lamagna, Antonino

2000-02-01

Polycrystalline pure and V-doped SnO2 thin films have been prepare by pulsed laser deposition (PLD) on Si substrates, with a Si3Ni4 buffered layer. PLD technique, under proper conditions, has probed to produce nanocrystalline-structured materials, which are suitable for gas sensing. In this work we analyze the role of V doping in the structural properties and in the electrical conductivity of the films. The deposition temperature was fixed at 600 degrees C and the films were grown in oxygen atmosphere. The films resulted nanocrystalline with 50 to 120 nm average grain size connected by necks with high surface areas. The microstructural and electronic properties of all the films were analyzed using scanning-electron microscopy, x-ray diffraction and conversion electron Moessbauer spectroscopy. Electrical conductance in a dynamic regime in dry synthetic air has been evaluated as a function of temperature. Moessbauer spectra reveal the presence of 15 percent of Sn2+ in the 5at. percent V-doped films. At about 340 degrees C, a strong increase in the conductivity of the films occurs. Possible explanations are that thermal energy could excite electrons from the vanadium ions into the crystal's conduction band or promotes the diffusion of surface oxygen vacancies towards the bulk, increasing strongly the conductivity of the film.

Martian Magnets Under the Microscope

NASA Technical Reports Server (NTRS)

2004-01-01

NASA's Mars Exploration Rover Spirit acquired this microscopic imager view of its capture magnet on sol 92 (April 6, 2004). Both Spirit and the Mars Exploration Rover Opportunity are equipped with a number of magnets. The capture magnet, as seen here, has a stronger charge than its sidekick, the filter magnet. The lower-powered filter magnet captures only the most magnetic airborne dust with the strongest charges, while the capture magnet picks up all magnetic airborne dust.

The magnets' primary purpose is to collect the martian magnetic dust so that scientists can analyze it with the rovers' Moessbauer spectrometers. While there is plenty of dust on the surface of Mars, it is difficult to confirm where it came from, and when it was last airborne. Because scientists are interested in learning about the properties of the dust in the atmosphere, they devised this dust-collection experiment.

The capture magnet is about 4.5 centimeters (1.8 inches) in diameter and is constructed with a central cylinder and three rings, each with alternating orientations of magnetization. Scientists have been monitoring the continual accumulation of dust since the beginning of the mission with panoramic camera and microscopic imager images. They had to wait until enough dust accumulated before they could get a Moessbauer spectrometer analysis. The results of that analysis, performed on sol 92, have not been sent back to Earth yet.

Moessbauer studies in zinc-manganese ferrites for use in measuring small velocities and accelerations with great precision

NASA Technical Reports Server (NTRS)

Escue, W. T.; Gupta, R. G.; Mendiratta, R. G.

1975-01-01

Mossbauer spectroscopy was used for a systematic study of the magnetic behavior of manganese and zinc in mixed ferrites. It was observed that Zn2+ has preference to substitute Mn2+ at interstitial sites where the metal ions are tetrahedrally coordinated with four oxygen neighbors. The internal magnetic hyperfine field at the tetrahedral iron site is larger than that at the octahedral site. The relaxation effects were observed to play an important role as the zinc contents were increased, while the spin-correlation time and the magnetic field were observed to decrease in strength. It is concluded that Mossbauer effect data on complex materials, when used in conjunction with other data, can provide useful insight into the origin of the microscopic properties of magnetic materials.

Adirondack's Inner Self

NASA Technical Reports Server (NTRS)

2004-01-01

This spectrum - the first taken of a rock on another planet - reveals the different iron-containing minerals that makeup the martian rock dubbed Adirondack. It shows that Adirondack is a type of volcanic rock known as basalt. Specifically, the rock is what is called olivine basalt because in addition to magnetite and pyroxene, two key ingredients of basalt, it contains a mineral called olivine. This data was acquired by Spirit's Moessbauer spectrometer before the rover developed communication problems with Earth on the 18th martian day, or sol, of its mission.

Coupling Nuclear Induced Phonon Propagation with Conversion Electron Moessbauer Spectroscopy

DTIC Science & Technology

2015-06-18

penetrating and a small detector with low density will be insensitive to the gammas. Thus, a small gas proportional counter is ideal for this application ...and Materials Science Vol. 1. Plenum: New York, 1993. 16. Long, G. J. and Stevens, J. G., eds. (1986) " Industrial applications of the Mössbauer...proportional gas detector attached to left side of 1” diameter stainless steel type-310 bar, phonon source encased in a mounting device attached to the right

Non-Destructive Classification Approaches for Equilbrated Ordinary Chondrites

NASA Technical Reports Server (NTRS)

Righter, K.; Harrington, R.; Schroeder, C.; Morris, R. V.

2013-01-01

Classification of meteorites is most effectively carried out by petrographic and mineralogic studies of thin sections, but a rapid and accurate classification technique for the many samples collected in dense collection areas (hot and cold deserts) is of great interest. Oil immersion techniques have been used to classify a large proportion of the US Antarctic meteorite collections since the mid-1980s [1]. This approach has allowed rapid characterization of thousands of samples over time, but nonetheless utilizes a piece of the sample that has been ground to grains or a powder. In order to compare a few non-destructive techniques with the standard approaches, we have characterized a group of chondrites from the Larkman Nunatak region using magnetic susceptibility and Moessbauer spectroscopy.

Mineralogy, chemical composition, and microstructure of ferrospheres in fly ashes from coal combustion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yongchun Zhao; Junying Zhang; Junmin Sun

2006-08-15

Fourteen samples of coal and ferrospheres, which were recovered by dry magnetic separation from fly ashes, were collected from five power plants in China. The mineralogy, chemical composition, and microstructure of ferrospheres in fly ashes have been studied by optical microscopy, X-ray diffraction (XRD), Moessbauer spectroscopy, and field emission scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy (FSEM-EDX). Iron in ferrospheres mainly occurs as Fe{sub 3}O{sub 4}, {alpha}Fe{sub 2}O{sub 3}, {gamma}Fe{sub 2}O{sub 3}, MgFe{sub 2}O{sub 4}, and Fe{sup 3+}-glass, ferrian spinel, and so on. On the basis of iron content, the ferrospheres in fly ashes are classified into four groups,more » namely ferrooxides, aluminosilicate-bearing ferrooxides, high-ferriferous aluminosilicates, and ferroaluminosilicates . Ferrooxides are derived from the oxidation of iron-bearing minerals, whereas aluminosilicate-bearing ferrooxides, high-ferriferous aluminosilicates, and ferroaluminosilicates are formed by the fusion of different proportions of inherent iron-bearing minerals and clay minerals. According to their microstructure, the ferrospheres in fly ashes are classified into seven groups, namely sheet ferrospheres, dendritic ferrospheres, granular ferrospheres, smooth ferrospheres, ferroplerospheres, porous ferrospheres, and molten drop ferrospheres. Sheet ferrospheres are derived from the oxidation of iron-bearing minerals immediately; smooth ferrospheres, molten drop ferrospheres, ferroplerospheres, and porous ferrospheres are the complex eutectic of inherent iron-bearing minerals and clay minerals; dendritic ferrospheres and granular ferrospheres are formed by the conglutination after the oxidation of iron-bearing minerals. Ferrooxides and aluminosilicate-bearing ferrooxides are important sources of the initial layer that occurs in deposits formed in coal-burning systems. 78 refs., 11 figs., 4 tabs.« less

'Berries' on the Ground 2 (3-D)

NASA Technical Reports Server (NTRS)

2004-01-01

This is the 3-D anaglyph showing a microscopic image taken of soil featuring round, blueberry-shaped rock formations on the crater floor at Meridiani Planum, Mars. This image was taken on the 13th day of the Mars Exploration Rover Opportunity's journey, after the Moessbauer spectrometer, an instrument located on the rover's instrument deployment device, or 'arm,' was pressed down to measure the soil's iron mineralogy. Note the donut-shaped imprint of the instrument in the lower part of the image. The area in this image is approximately 3 centimeters (1.2 inches) across.

Moessbauer/XRF MIMOS Instrumentation and Operation During the 2012 Analog Field Test on Mauna Kea Volcano, Hawaii

NASA Technical Reports Server (NTRS)

Graff, Trevor G.; Morris, R. V.; Klingelhofer, G.; Blumers, M.

2013-01-01

Field testing and scientific investigations were conducted on the Mauna Kea Volcano, Hawaii, as part of the 2012 Moon and Mars Analog Mission Activities (MMAMA). Measurements were conducted using both stand-alone and rover-mounted instruments to determine the geophysical and geochemical properties of the field site, as well as provide operational constraints and science considerations for future robotic and human missions [1]. Reported here are the results from the two MIMOS instruments deployed as part of this planetary analog field test.

Iron-sulfur mineralogy of Mars - Magmatic evolution and chemical weathering products

NASA Technical Reports Server (NTRS)

Burns, Roger G.; Fisher, Duncan S.

1990-01-01

Models are developed for the magmatic evolution and the oxidative weathering of sulfide minerals on Mars, based on petrogenetic associations among komatiitic rock types, Viking geochemical data, SNC meteorites, and terrestrial Fi-Ni deposits. The weathering model was tested by exposing komatiitic pyrrhotites and olivines to sulfuric acid solutions, with or without dissolved ferric iron, and identifying the reaction products by Moessbauer spectroscopy. The results suggest that, on Mars, acidic groundwater has induced oxidative weathering of pyrrhotite, yielding FeS2 and then FeOOH.

Moessbauer Spectroscopy for Lunar Resource Assessment: Measurement of Mineralogy and Soil Maturity

NASA Technical Reports Server (NTRS)

Morris, R. V.; Agresti, D. G.; Shelfer, T. D.; Pimperl, M. M.; Shen, M.-H.; Gibson, M. A.; Wills, E. L.

1992-01-01

First-order assessment of lunar soil as a resource includes measurement of its mineralogy and maturity. Soils in which the mineral ilmenite is present in high concentrations are desirable feedstock for the production of oxygen at a lunar base. The maturity of lunar soils is a measure of their relative residence time in the upper 1 mm of the lunar surface. Increasing maturity implies increasing load of solar wind species (e.g., N, H, and He-3), decreasing mean grain size, and increasing glass content. All these physicochemical properties that vary in a regular way with maturity are important parameters for assessing lunar soil as a resource. For example, He-3 can be extracted and potentially used for nuclear fusion. A commonly used index for lunar soil maturity is I(sub s)/FeO, which is the concentration of fine-grained metal determined by ferromagnetic resonance (I(sub s)) normalized to the total iron content (as FeO). I(sub s)/FeO has been measured for virtually every soil returned by the Apollo and Luna missions to the Moon. Because the technique is sensitive to both oxidation state and mineralogy, iron Moessbauer spectroscopy (FeMS) is a viable technique for in situ lunar resource assessment. Its utility for mineralogy is apparent from examination of published FeMS data for lunar samples. From the data published, it can be inferred that FeMS data can also be used to determine soil maturity. The use of FeMS to determine mineralogy and maturity and progress on development of a FeMS instrument for lunar surface use are discussed.

Interfacial chemical reactions between MoS2 lubricants and bearing materials

NASA Technical Reports Server (NTRS)

Zabinski, J. S.; Tatarchuk, B. J.

1989-01-01

XPS and conversion-electron Moessbauer spectroscopy (CEMS) were used to examine iron that was deposited on the basal plane of MoS2 single crystals and subjected to vacuum annealing, oxidizing, and reducing environments. Iron either intercalated into the MoS2 structure or formed oriented iron sulfides, depending on the level of excess S in the MoS2 structure. CEMS data demonstrated that iron sulfide crystal structures preferentially aligned with respect to the MoS2 basal plane, and that alignment (and potentially adhesion) could be varied by appropriate high-temperature annealing procedures.

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCammon, C.; Dubrovinsky, L.; Narygina, O.

We investigated the spin state of iron in Mg{sub 0.82}Fe{sub 0.18}SiO{sub 3} silicate perovskite using Moessbauer spectroscopy and nuclear forward scattering (NFS) at pressures up to 130 GPa and temperatures up to 1000 K. Majorite starting material was loaded into diamond anvil cells in three separate experiments, and transformed to silicate perovskite through laser heating. We found, in agreement with previous work, the predominance of a component with high isomer shift ({approx}1 mm/s relative to {alpha}-Fe) and high-quadrupole splitting (QS) (>4 mm/s) in Moessbauer and NFS spectra up to 115 GPa at room temperature, and in accordance with previous workmore » this component was assigned to intermediate-spin Fe{sup 2+}. At higher pressures, the intensity of the high QS component in the silicate perovskite spectrum decreased, while the intensity of a new component with low isomer shift ({approx}0 mm/s relative to {alpha}-Fe) and low quadrupole splitting (<0.5 mm/s) increased. This new component was assigned to low-spin Fe{sup 2+}, and its intensity increased with both increasing pressure and increasing temperature: at 120 GPa and 1000 K all Fe{sup 2+} was in the low-spin state. X-ray diffraction data showed well crystallized perovskite in all runs, and although the stable phase above 110 GPa is expected to be post-perovskite, sluggish transition kinetics likely preserved the perovskite phase in a metastable state. Our results combined with data in the literature and thermodynamic and topological considerations suggest that there may be a region where silicate perovskite containing low-spin Fe{sup 2+} is stable, which coincides with predicted pressure-temperature conditions near the D{double_prime} layer.« less

Local ordering and magnetism in Ga{sub 0.9}Fe{sub 3.1}N

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burghaus, Jens; Sougrati, Moulay T., E-mail: moulay-tahar.sougrati@univ-montp2.fr; Moechel, Anne

Prior investigations of the ternary nitride series Ga{sub 1-x}Fe{sub 3+x}N (0{<=}x{<=}1) have indicated a transition from ferromagnetic {gamma}'-Fe{sub 4}N to antiferromagnetic 'GaFe{sub 3}N'. The ternary nitride 'GaFe{sub 3}N' has been magnetically and spectroscopically reinvestigated in order to explore the weakening of the ferromagnetic interactions through the gradual incorporation of gallium into {gamma}'-Fe{sub 4}N. A hysteretic loop at RT reveals the presence of a minority phase of only 0.1-0.2 at%, in accord with the sound two-step synthesis. The composition of the gallium-richest phase 'GaFe{sub 3}N' was clarified by Prompt Gamma-ray Activation Analysis and leads to the berthollide formula Ga{sub 0.91(1)}Fe{sub 3.09(10)}N{submore » 1.05(7)}. Magnetic measurements indicate a transition around 8 K, further supported by Moessbauer spectral data. The weakening of the ferromagnetic coupling through an increasing gallium concentration is explained by a simple Stoner argument. In Ga{sub 0.9}Fe{sub 3.1}N, the presence of iron on the gallium site affects the magnetism by the formation of 13-atom iron clusters. - Graphical Abstract: The crystal structure of GaFe{sub 3}N with green nitrogen atoms in the very center, red iron atoms at the face centers, and gray gallium atoms at the corner positions. Highlights: > Almost phase-pure synthesis of Ga{sub 0.9}Fe{sub 3.1}N. > Prompt gamma-ray activation analysis yields precise composition. > Magnetic ordering of the facial Fe atoms at the lowest temperatures. > Moessbauer spectroscopy suggests percolation or RKKY-type interaction. > Fe{sub 13} clusters due to berthollide character.« less

Moessbauer Spectroscopy of Martian and Sverrefjell Carbonates

NASA Technical Reports Server (NTRS)

Agresti, David G.; Morris, Richard V.

2011-01-01

Mars, in its putative "warmer, wetter: early history, could have had a CO2 atmosphere much denser than its current value of <10 mbar. The question of where all this early CO2 has gone has long been debated. Now, several instruments on Mars Exploration Rover (MER) Spirit, including its Moessbauer spectrometer MIMOS II, have identified Mg-Fe carbonate in rock outcrops at Comanche Spur in the Columbia Hills of Gusev Crater. With this finding, carbonate cements in volcanic breccia collected on Sverrefjell Volcano on Spitzbergen Island in the Svalbard Archipelago (Norway) during the AMASE project are mineralogical and possible process analogues of the newly discovered martian carbonate. We report further analyses of Mossbauer spectra from Comanche Spur and discuss their relationship to Mossbauer data acquired on Sverrefjell carbonates. The spectra were velocity calibrated with MERView and fit using MERFit. Instead of the "average temperature" Comanche spectrum (data from all temperature windows summed), we refit the Comanche data for QS within each temperature window, modeling as doublets for Fe2+(carbonate), Fe2+(olivine), and Fe3+(npOx). The temperature dependences of QS for the Comanche carbonate and for a low-Ca carbonate from Chocolate Pots in Yellowstone National Park (YNP) are shown; they are the same within error. For Comanche carbonate summed over 210-270 K, (CS, QS) = (1.23, 1.95) mm/s. The value of QS for Sverrefjell carbonate at 295 K, (CS, QS) = (1.25, 1.87) mm/s, is also plotted, and the plot shows that the QS for the Sverrefjell carbonate agrees within error with the Comanche data extrapolated to 295 K. This agreement is additional evidence that the Sverrefjell carbonates are Mossbauer analogues for the Comanche carbonates, and that both carbonates might have precipitated from solutions that became carbonate rich by passing through buried carbonate deposits.

Recent Results from the Mars Exploration Rover Spirit Mission

NASA Astrophysics Data System (ADS)

Squyres, S. W.

2005-05-01

Since arriving at the Columbia Hills, the Spirit rover's primary area of geologic investigation has been the West Spur of Husband Hill. Pancam images of West Spur rocks show morphology ranging from massive to finely layered. Microscopic Imager images show the rocks to be clastic in nature, with a substantial range in grain sizes. Grains vary from rounded to angular. Mini-TES data show little variability from one rock to the next, and the best fit to the IR spectral signature of the rocks is dominated by basaltic glass. The chemistry revealed by the APXS is broadly basaltic in nature, but substantially enhanced in P, S, Cl, and Br relative to plains rocks. Moessbauer data show that olivine is absent in West Spur rocks, and pyroxene signatures are weak. Fe oxides and oxyhydroxides are present. We interpret the rocks of the West Spur to be aqueously altered basaltic materials of volcaniclastic or impact origin. Since leaving the West Spur, Spirit has explored toward the northeast, higher onto Husband Hill. Loose rocks ("float") on the north flank of the hill are dominated by another poorly sorted clastic lithology that contains olivine and that has strikingly high abundances of Ti and P. Only a few bedrock outcrops have been identified on the main body of Husband Hill. All of these examined to date consist of a coarse-grained clastic rock dominated by basaltic chemistry and cemented by sulfate salts. Grain sizes range up to several mm, and sub-cm layering is present. Moessbauer data show pyroxene, olivine, and a high abundance of magnetite in the basaltic component. APXS data are consistent with the rock being up to 20 percent magnesium sulfate salts by mass, and microscopic images show a high degree of cementation by these salts.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shenoy, G. K.; Rohlsberger, R.; X-Ray Science Division

From the beginning of its discovery the Moessbauer effect has continued to be one of the most powerful tools with broad applications in diverse areas of science and technology. With the advent of synchrotron radiation sources such as the Advanced Photon Source (APS), the European Synchrotron Radiation Facility (ESRF) and the Super Photon Ring-8 (SPring-8), the tool has enlarged its scope and delivered new capabilities. The popular techniques most generally used in the field of materials physics, chemical physics, geoscience, and biology are hyperfine spectroscopy via elastic nuclear forward scattering (NFS), vibrational spectroscopy via nuclear inelastic scattering (NRIXS), and, tomore » a lesser extent, diffusional dynamics from quasielastic nuclear forward scattering (QNFS). As we look ahead, new storage rings with enhanced brilliance such as PETRA-III under construction at DESY, Hamburg, and PEP-III in its early design stage at SLAC, Stanford, will provide new and unique science opportunities. In the next two decades, x-ray free-electron lasers (XFELs), based both on self-amplified spontaneous emission (SASE-XFELs) and a seed (SXFELs), with unique time structure, coherence and a five to six orders higher average brilliance will truly revolutionize nuclear resonance applications in a major way. This overview is intended to briefly address the unique radiation characteristics of new sources on the horizon and to provide a glimpse of scientific prospects and dreams in the nuclear resonance field from the new radiation sources. We anticipate an expanded nuclear resonance research activity with applications such as spin and phonon mapping of a single nanostructure and their assemblies, interfaces, and surfaces; spin dynamics; nonequilibrium dynamics; photochemical reactions; excited-state spectroscopy; and nonlinear phenomena.« less

Elasticity and magnetocaloric effect in MnFe 4Si 3

DOE PAGES

Herlitschke, Marcus; Klobes, B.; Sergueev, I.; ...

2016-03-16

The room temperature magnetocaloric material MnFe 4Si 3 was investigated with nuclear inelastic scattering (NIS) and resonant ultrasound spectroscopy (RUS) at different temperatures and applied magnetic fields in order to assess the infuence of the magnetic transition and the magnetocaloric effect on the lattice dynamics. The NIS data give access to phonons with energies above 3 meV, whereas RUS probes the elasticity of the material in the MHz frequency range and thus low energy, ~5 neV, phonon modes. A significant infuence of the magnetic transition on the lattice dynamics is observed only in the low energy region. Here, MnFe 4Simore » 3 and other compounds in the Mn 5-xFe xSi 3 series were also investigated with vibrating sample magnetometry, resistivity measurements and Moessbauer spectroscopy in order to study the magnetic transitions and to complement the obtained results on the lattice dynamics.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cagnoli, M.V.; Marchetti, S.G.; Gallegos, N.G.

In order to study the influence of the support on high dispersion catalysts used for the CO hydrogenation reaction, two catalysts, Fe/SiO{sub 2} and Fe/Al{sub 2}O{sub 3}, were prepared by the dry impregnation method. Selective chemisorption of CO, volumetric oxidation, and Moessbauer spectroscopy were used to determine the Fe species present as well as the metallic crystal size, the degree of dispersion, and the reduction percentage. The presence of small Fe{sup 0} crystallites with high dispersion was determined in both catalysts. Reaction rates were measured in a differential reactor and significant differences, about one order of magnitude less for themore » Al{sub 2}O{sub 3} than for the SiO{sub 2} supported catalysts, were found in the methane turnover frequencies. They are attributed to the interaction between the metal and the supports. The selectivity differences is also discussed in connection with distinct surface properties.« less

Effects of the chemical environment on the spectroscopic properties of clays: Applications for Mars

NASA Technical Reports Server (NTRS)

Bishop, Janice L.; Pieters, Carle M.

1992-01-01

Laboratory studies of Mars soil analogs pose unique problems, since soils interact readily with their environment and exhibit variable characteristics depending on the environment. We have performed a series of experiments focusing on the spectral properties of clays and how they vary as a function of composition and environment, including examination of fundamental as well as overtone absorptions, that occur in the mid- and near-IR, respectively. Smectite clays have been selected in our laboratory experiments as a primary surface analog for Mars because of their compatibility with results of the Viking biology experiments, their stability under current martian conditions, and their compatibility with reflectance spectra of Mars. We prepared a number of monoionic montmorillonites in order to examine the influence of cations on the water molecules in the clay interlayer region. Moessbauer spectra of several montmorillonites with variable amounts of interlayer iron confirm the presence of ferrihydrite.

Evidence for pigmentary hematite on Mars based on optical, magnetic, and Moessbauer studies of superparamagnetic (nanocrystalline) hematite

NASA Technical Reports Server (NTRS)

Morris, Richard V.; Agresti, David G.; Newcomb, Jeffery A.; Shelfer, Tad D.; Lauer, Howard V., Jr.

1989-01-01

Samples containing variable amounts of superparamagnetic hematite (sp-Hm) were prepared by a method in which the sp-Hm particles were dispersed throughout larger particles of silica gel, and the optical and magnetic properties of these samples were compared with those of larger-diameter hematite (bulk-Hm). It is shown that the optical properties of sp-Hm are different from those of bulk-Hm. Implications of the results for mineralogical interpretations of spectral data for the Martian surface and its terrestrial analogues are discussed. It is concluded that features resulting from ferric iron in the Martian spectral data and the results of the Viking magnetic properties experiment are both consistent with hematite present as both sp-Hm and bulk-Hm; the hematite particles most likely occur in pigmentary form, i.e., as particles dispersed throughout the volume of a spectrally neutral material.

Red Marks the Spot

NASA Technical Reports Server (NTRS)

2004-01-01

This hematite abundance index map helps geologists choose hematite-rich locations to visit around Opportunity's landing site. Blue dots equal areas low in hematite and red dots equal areas high in hematite.

Why Hematite Geologists are eager to reach the hematite-rich area in the upper left to closely examine the soil, which may reveal secrets about how the hematite got to this location. Knowing how the hematite on Mars was formed may help scientists characterize the past environment and determine whether that environment provided favorable conditions for life.

The Plan Over the next few sols, engineers and scientists plan to drive Opportunity to the hematite-rich area then attempt a 'pre-trench' sequence, taking measurements with the Moessbauer spectrometer, alpha particle X-ray spectrometer and microscopic imager. Next, the plan is to trench the hematite rich area by spinning one wheel in place to 'dig' a shallow hole. Finally, scientists will aim the instrument arm back at the same area where it pre-trenched to get post-trench data with the same instruments to compare and contrast the levels of hematite and revel how deep the hematite lays in the dirt.

Index Map Details The hematite abundance index map was created using data from the miniature thermal emission instrument. The first layer is a mosaic of panoramic camera images taken prior to egress, when Opportunity was still on the lander. The colored dots represent data collected by the miniature thermal emission spectrometer on sol 11, after Opportunity had rolled off of the lander and the rover was located at the center of the blue semi-circle.

The spectrometer is located on the panoramic camera mast. On sol 11, it took a low-angle 180-degree panorama of the area in front of the rover, indicated by the blue shaded dots. The instrument then raised the angle of its field of view a few degrees higher to sweep around behind the rover, indicated by the red and yellow dots offset at the far sides of the image.

JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover project for NASA's Office of Space Science, Washington, D.C.

Nanosized iron and chromium oxides supported on mesoporous CeO2 and SBA-15 silica: Physicochemical and catalytic study

NASA Astrophysics Data System (ADS)

Tsoncheva, Tanya; Roggenbuck, Jan; Paneva, Daniela; Dimitrov, Momtchil; Mitov, Ivan; Fröba, Michael

2010-11-01

Mesoporous ceria and SBA-15 silica were modified with iron and chromium oxide nanoparticles and characterized by XRD, N2-physisorption, FTIR, UV-vis, Moessbauer spectroscopy and TPR-TG in hydrogen. Their catalytic behaviour in methanol decomposition to CO and hydrogen was also studied. Stabilization of mono- and bi-chromate species, FeOx patches or isolated iron ions as well as Fe2O3 and Cr2O3 nanoparticles in different ratio depending on the nature of the porous matrix was observed. The simultaneous presence of iron and chromium oxides lead to change in their dispersion, providing easier reducibility, higher catalytic activity and stability of the obtained materials in comparison with the corresponding mono-component ones. The "intimate contact" at the interface of both loaded metal oxide nanoparticles and the support was discussed with respect to explain the differences in the state of the active ingredient and its specific catalytic behaviour.

Size-dependent effects in supported highly dispersed Fe2O3 catalysts, doped with Pt and Pd

NASA Astrophysics Data System (ADS)

Cherkezova-Zheleva, Zara; Shopska, Maya; Mitov, Ivan; Kadinov, Georgi

2010-06-01

Series of Fe and Fe-Me (Me = Pt or Pd) catalyst supported on γ-Al2O3, TiO2 (anatase) or diatomite were prepared by the incipient wetness impregnation method. The metal loading was 8 wt.% Fe and 0.7 wt.% noble metal. The preparation and pretreatment conditions of all studied samples were kept to be the same. X-ray diffraction, Moessbauer spectroscopy, X-ray photoelectron spectroscopy and temperature-programmed reduction are used for characterization of the supports and the samples at different steps during their treatment and catalytic tests. The catalytic activity of the samples was tested in the reaction of total benzene oxidation. The physicochemical and catalytic properties of the obtained materials are compared with respect of the different chemical composition, dispersion of used carriers and of the supported phases. Samples with the same composition prepared by mechanical mixing are studied as catalysts for comparison and for clearing up the presence of size-dependent effect, also.

'King George Island' Brushed

NASA Technical Reports Server (NTRS)

2006-01-01

[figure removed for brevity, see original site] Annotated Version

This mosaic was made from frames acquired by the microscopic imager on NASA's Mars Exploration Rover Spirit during Spirit's 1,031 Martian day, or sol, on the red planet (Nov. 27, 2006). It shows a rock target called 'King George Island' after the target was brushed by the rover's rock abrasion tool. The mosaic covers approximately 6 centimeters (2.4 inches) across and shows the granular nature of the rock exposure. The grains are typically about 1 millimeter (.04 inches) wide. Data from the rover's Moessbauer spectrometer provides evidence that they have an enhanced amount of the mineral hematite relative to surrounding soils.

A Bowl of Hematite-Rich 'Berries'

NASA Technical Reports Server (NTRS)

2004-01-01

This graph shows two spectra of outcrop regions near the Mars Exploration Rover Opportunity's landing site. The blue line shows data for a region dubbed 'Berry Bowl,' which contains a handful of the sphere-like grains dubbed 'blueberries.' The yellow line represents an area called 'Empty' next to Berry Bowl that is devoid of berries. Berry Bowl's spectrum still shows typical outcrop characteristics, but also exhibits an intense hematite signature, seen as a 'magnetic sextet.' Hematite is an iron-bearing mineral often formed in water. These spectra were taken by the rover's Moessbauer spectrometer on the 46th (Empty) and 48th (Berry Bowl) martian days, or sols, of its mission.

NASA MSU Status Report. [Research on high T(sub c) superconducting compounds

NASA Technical Reports Server (NTRS)

Oliver, Frederick W.

1995-01-01

Our laboratory concentrations consisted of several parts: (1) we made several presentations of the work sponsored by NASA covered under the last status report period; (2) we irradiated and successfully completed Moessbauer measurements on a high temperature superconductor; (3) we continued the improvement of our laboratory with the development of improved software; and (4) we made modifications of equipment to increase the efficiency and decrease the time necessary for completing an experimental investigation. In addition to our research results, this report contains a copy of the last financial report submitted by the University's business office that was related to this grant.

Cation distributions on rapidly solidified cobalt ferrite

NASA Technical Reports Server (NTRS)

De Guire, Mark R.; Kalonji, Gretchen; O'Handley, Robert C.

1990-01-01

The cation distributions in two rapidly solidified cobalt ferrites have been determined using Moessbauer spectroscopy at 4.2 K in an 8-T magnetic field. The samples were obtained by gas atomization of a Co0-Fe2O3-P2O5 melt. The degree of cation disorder in both cases was greater than is obtainable by cooling unmelted cobalt ferrite. The more rapidly cooled sample exhibited a smaller departure from the equilibrium cation distribution than did the more slowly cooled sample. This result is explained on the basis of two competing effects of rapid solidification: high cooling rate of the solid, and large undercooling.

'Bounce': Not Like the Others

NASA Technical Reports Server (NTRS)

2004-01-01

This illustration shows that the rock dubbed 'Bounce' near the Mars Exploration Rover Opportunity's landing region at Meridiani Planum is not made up of the same minerals as surrounding soil. Spectra from three soil samples taken outside of 'Eagle Crater' are compared to that of Bounce (bottom). The dashed white line in the center of the spectra indicates where the 'fingerprint' for triple-oxidized iron (Fe 3+) occurs. While the soil samples possess this feature, Bounce does not. The results suggest that Bounce did not originate in the plains of Meridiani Planum. These spectra were taken by the rover's Moessbauer spectrometer. Measurements of Bounce were made on sol 67.

2003 Mars Exploration Rover Mission: Robotic Field Geologists for a Mars Sample Return Mission

NASA Technical Reports Server (NTRS)

Ming, Douglas W.

2008-01-01

The Mars Exploration Rover (MER) Spirit landed in Gusev crater on Jan. 4, 2004 and the rover Opportunity arrived on the plains of Meridiani Planum on Jan. 25, 2004. The rovers continue to return new discoveries after 4 continuous Earth years of operations on the surface of the red planet. Spirit has successfully traversed 7.5 km over the Gusev crater plains, ascended to the top of Husband Hill, and entered into the Inner Basin of the Columbia Hills. Opportunity has traveled nearly 12 km over flat plains of Meridiani and descended into several impact craters. Spirit and Opportunity carry an integrated suite of scientific instruments and tools called the Athena science payload. The Athena science payload consists of the 1) Panoramic Camera (Pancam) that provides high-resolution, color stereo imaging, 2) Miniature Thermal Emission Spectrometer (Mini-TES) that provides spectral cubes at mid-infrared wavelengths, 3) Microscopic Imager (MI) for close-up imaging, 4) Alpha Particle X-Ray Spectrometer (APXS) for elemental chemistry, 5) Moessbauer Spectrometer (MB) for the mineralogy of Fe-bearing materials, 6) Rock Abrasion Tool (RAT) for removing dusty and weathered surfaces and exposing fresh rock underneath, and 7) Magnetic Properties Experiment that allow the instruments to study the composition of magnetic martian materials [1]. The primary objective of the Athena science investigation is to explore two sites on the martian surface where water may once have been present, and to assess past environmental conditions at those sites and their suitability for life. The Athena science instruments have made numerous scientific discoveries over the 4 plus years of operations. The objectives of this paper are to 1) describe the major scientific discoveries of the MER robotic field geologists and 2) briefly summarize what major outstanding questions were not answered by MER that might be addressed by returning samples to our laboratories on Earth.

Francis Bitter National Magnet Laboratory annual report, July 1988 through June 1989

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1989-01-01

Contents include: reports on laboratory research programs--magneto-optics and semiconductor physics, magnetism, superconductivity, solid-state nuclear magnetic resonance, condensed-matter chemistry, biomagnetism, magnet technology, instrumentation for high-magnetic-field research, molecular biophysics; reports of visiting scientists--reports of users of the High Magnetic Field Facility, reports of users of the Pulsed Field Facility, reports of users of the SQUID Magnetometer and Moessbauer Facility, reports of users of the High-Field NMR Facility; Appendices--publications and meeting speeches, organization, summary of High-Field Magnet Facility use January 1, 1981 through December 31, 1988; geographic distribution of High-Field Magnet users (excluding laboratory staff); and summary of educational activities.

Acid-Sulfate Alteration at Gusev Crater and Across Mars: High-SiO2 Residues and Ferric Sulfate Precipitates

NASA Technical Reports Server (NTRS)

Morris, R. V.; Catalano, J. G.; Klingelhoefer, G.; Schroeder, C.; Gellert, R.; Clark, B. C.; Ming, D. W.; Yen, A. S.; Arvidson, R. E.; Cohen, B. A.;

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gallegos, N.G.; Alvarez, A.M.; Cagnoli, M.V.

SiO{sub 2} covered with MgO has been used as support of iron catalysts in the Fischer-Tropsch reaction. Catalysts of 5% (w/w) iron concentration and 2, 4, and 8% (w/w) of MgO on SiO{sub 2} were prepared. Selective chemisorption of CO, volumetric oxidation, and Moessbauer spectroscopy were used to characterize the type of iron species and the metallic crystal sizes. MgO covers the SiO{sub 2} surface and modifies the metallic crystal size. The activity to total hydrocarbons increases with the amount of MgO added. An optimal concentration of about 4% (w/w) was found to have the highest selectivity to olefins. 45more » refs., 13 figs., 3 tabs.« less

Moessbauer Mineralogy of Rock, Soil, and Dust at Gusev Crater, Mars: Spirit's Journey through Weakly Altered Olivine Basalt on the Plains and Pervasively Altered Basalt in the Columbia Hills

NASA Technical Reports Server (NTRS)

Morris, R. V.; Klingelhoefer, G.; Schroeder, C.; Rodionov, D. S.; Yen, A.; Ming, D. W.; deSouza, P. A., Jr.; Fleischer, I.; Wdowiak, T.; Gellert, R.;

Effect of oxygen impurities on properties of the ternary superconductor SnMo/sub 6/S/sub 8/: Extended x-ray-absorption fine-structure determination of bond distances and local-density cluster calculations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guenzburger, D.; Ellis, D.E.; Montano, P.A.

1985-10-01

Electronic structure calculations were performed for clusters representing the Chevrel-phase SnMo/sub 6/S/sub 8/, with and without oxygen doping. In order to obtain the local structure around the Sn atom, extended x-ray-absorption fine-structure (EXAFS) measurements were made with synchro- tron radiation. The interatomic distances obtained experimentally were used in the calculations. The effect of oxygen doping on the Moessbauer isomer shift and quadrupole splitting values of /sup 119/Sn was investigated theoretically and compared with reported experimental values. The effect of oxygen substitution on the density of states at the Fermi energy of the (Mo/sub 6/S/sub 8/)/sup 2 -/ cluster was alsomore » studied. The results suggest that oxygen doping does not alter significantly the electronic structure of SnMo/sub 6/S/sub 8/.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu Qiang; Zeng Xierong; Shenzhen Key Laboratory of Special Functional Materials, Shenzhen 518060

This paper reports the observation of the clear Invar effects of (Fe{sub 71.2}B{sub 24}Y{sub 4.8}){sub 96}Nb{sub 4} bulk metallic glass. The Invar effects of (Fe{sub 71.2}B{sub 24}Y{sub 4.8}){sub 96}Nb{sub 4} alloys in different structural states are also investigated in situ through cyclic thermal dilation tests at different cyclic temperatures. The results show that these Invar effects are strengthened in the relaxation amorphous state, weakened in the nanocrystalline state, and absent in the complete crystalline state. X-ray diffraction and Moessbauer spectroscopy demonstrate that the structural influences on Invar effects can be explained by the different local atomic arrangements around Fe atomsmore » in different structural states.« less

Mineral Tells Tale of Watery Past

NASA Technical Reports Server (NTRS)

2004-01-01

This spectrum, taken by the Mars Exploration Rover Opportunity's Moessbauer spectrometer, shows the presence of an iron-bearing mineral called jarosite in the collection of rocks dubbed 'El Capitan.' 'El Capitan' is located within the rock outcrop that lines the inner edge of the small crater where Opportunity landed. The pair of yellow peaks specifically indicates a jarosite phase, which contains water in the form of hydroxyl as a part of its structure. These data suggest water-driven processes exist on Mars. Three other phases are also identified in this spectrum: a magnetic phase (blue), attributed to an iron-oxide mineral; a silicate phase (green), indicative of minerals containing double-ionized iron (Fe 2+); and a third phase (red) of minerals with triple-ionized iron (Fe 3+).

Mineral Tells Tale of Watery Past-2

NASA Technical Reports Server (NTRS)

2004-01-01

This spectrum, taken by the Mars Exploration Rover Opportunity's Moessbauer spectrometer, shows the presence of an iron-bearing mineral called jarosite in the collection of rocks dubbed 'El Capitan.' 'El Capitan' is located within the outcrop that lines the inner edge of the small crater where Opportunity landed. The pair of yellow peaks specifically indicates a jarosite phase, which contains water in the form of hydroxyl as a part of its structure. These data suggest water-driven processes exist on Mars. Three other phases are also identified in this spectrum: a magnetic phase (blue), attributed to an iron-oxide mineral; a silicate phase (green), indicative of minerals containing double-ionized iron (Fe 2+); and a third phase (red) of minerals with triple-ionized iron (Fe 3+).

Misconceptions in recent papers on special relativity and absolute space theories

NASA Technical Reports Server (NTRS)

Torr, D. G.; Kolen, P.

1982-01-01

Several recent papers which purport to substantiate or negate arguments in favor of certain theories of absolute space have been based on fallacious principles. This paper discusses three related instances, indicating where misconceptions have arisen. It is established, contrary to popular belief, that the classical Lorentz ether theory accounts for all the experimental evidence which supports the special theory of relativity. It is demonstrated that the ether theory predicts the null results obtained from pulsar timing and Moessbauer experiments. It is concluded that a measurement of the one-way velocity of light has physical meaning within the context of the Lorentz theory, and it is argued that an adequately designed experiment to measure the one-way velocity of light should be attempted.

Windblown 'Whymper'

NASA Technical Reports Server (NTRS)

2005-01-01

[figure removed for brevity, see original site] Annotated image of PIA04193 Windblown 'Whymper'

NASA's Spirit rover took this mosaic of the undisturbed soil deposit 'Whymper' on martian day, or sol 588 (August 29, 2005), using its microscopic imager. A well-defined impression about 3 centimeters (1.2 inches) wide was created when the rover's Moessbauer spectrometer faceplate was gently pushed into the soil. Note that the surface of the soil has been modified into wind streaks.

The ability of the soil to make fine molds of the faceplate suggests the material is a mix of sand and dust. The dust is pushed into the pores of the sand and keeps the material from collapsing. This allows for very detailed impressions of the faceplate.

Pervasively Altered Hematite-Rich Deposits Southeast of Home Plate, Gusev Crater, Mars

NASA Technical Reports Server (NTRS)

Schroder, C.; Arvidson, R. E.; Schmidt, M. E.; Gellert, R.; Klingelhoefer, G.; Ming, D. W.; Morris, R. V.; Rice, J. W.; Yen, A. S.; deSouza, P. A., Jr.

2008-01-01

The investigation of Home Plate and its surroundings in the Inner Basin of the Columbia Hills in Gusev Crater has added substantially to the water story on Mars. Textural, morphological, and geochemical evidence from Home Plate point towards an explosive origin, probably a hydrovolcanic explosion [1]. High silica deposits in the immediate vicinity of Home Plate suggest hydrothermal alteration [e.g. 2,3]. Pervasively altered deposits rich in hematite were investigated to the southeast of Home Plate. Of these, the target Halley, the target KingGeorgeIsland on the GrahamLand outcrop, and the targets Montalva and Riquelme on the Troll outcrop were investigated in situ with the Alpha Particle X-ray spectrometer (APXS), the Microscopic Imager (MI), and the Moessbauer (MB) spectrometer (Fig. 1).

Martensitic phase transformations in the nanostructured surface layers induced by mechanical attrition treatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ni Zhichun; Wang Xiaowei; Wu Erdong

2005-12-01

Conversion electron Moessbauer spectroscopy (CEMS) and x-ray diffraction (XRD) analysis have been used to investigate the relationship between characteristics of phase transformation and the treatment time in surface nanocrystallized 316L stainless steel induced by surface mechanical attrition treatment (SMAT). A similar trend of development of the martensitic phase upon the treatment time has been observed from both CEMS and XRD measurements. However, in the CEMS measurement, two types of martensite phase with different magnetic hyperfine fields are revealed. Based on a random distribution of the non-iron coordinating atoms, a three-element theoretical model is developed to illustrate the difference of twomore » types of martensite phase. The calculated results indicate the segregation of the non-iron atoms associated with SMAT treatment.« less

Two Years of Chemical Sampling on Meridiani Planum by the Alpha Particle X-Ray Spectrometer Onboard the Mars Exploration Rover Opportunity

NASA Technical Reports Server (NTRS)

Bruckner, J.; Gellert, R.; Clark, B.C.; Dreibus, G.; Rieder, R.; Wanke, H.; d'Uston, C.; Economou, T.; Klingelhofer, G.; Lugmair, G.;

Acid Sulfate Alteration in Gusev Crater, Mars

NASA Technical Reports Server (NTRS)

Morris, R. V.; Ming, D. W.; Catalano, J. G.

2016-01-01

The Mars Exploration Rover (MER) Spirit landed on the Gusev Crater plains west of the Columbia Hills in January, 2004, during the Martian summer (sol 0; sol = 1 Martian day = 24 hr 40 min). Spirit explored the Columbia Hills of Gusev Crater in the vicinity of Home Plate at the onset on its second winter (sol approximately 900) until the onset of its fourth winter (sol approximately 2170). At that time, Spirit became mired in a deposit of fined-grained and sulfate-rich soil with dust-covered solar panels and unfavorable pointing of the solar arrays toward the sun. Spirit has not communicated with the Earth since sol 2210 (January, 2011). Like its twin rover Opportunity, which landed on the opposite side of Mars at Meridiani Planum, Spirit has an Alpha Particle X-Ray Spectrometer (APXS) instrument for chemical analyses and a Moessbauer spectrometer (MB) for measurement of iron redox state, mineralogical speciation, and quantitative distribution among oxidation (Fe(3+)/sigma Fe) and coordination (octahedral versus tetrahedral) states and mineralogical speciation (e.g., olivine, pyroxene, ilmenite, carbonate, and sulfate). The concentration of SO3 in Gusev rocks and soils varies from approximately 1 to approximately 34 wt%. Because the APXS instrument does not detect low atomic number elements (e.g., H and C), major-element oxide concentrations are normalized to sum to 100 wt%, i.e., contributions of H2O, CO2, NO2, etc. to the bulk composition care not considered. The majority of Gusev samples have approximately 6 plus or minus 5 wt% SO3, but there is a group of samples with high SO3 concentrations (approximately 30 wt%) and high total iron concentrations (approximately 20 wt%). There is also a group with low total Fe and SO3 concentrations that is also characterized by high SiO2 concentrations (greater than 70 wt%). The trend labeled "Basaltic Soil" is interpreted as mixtures in variable proportions between unaltered igneous material and oxidized and SO3-rich basaltic dust. The Moessbauer parameters are not definitive for mineralogical speciation (other than octahedrally-coordinated Fe(3+) but are consistent with a schwertmannite-like phase (i.e., a nanophase ferric oxide). The high oxidation state and values of Moessbauer parameters (center shift and quadrupole splitting) for the high-SO3 samples imply ferric sulfate (i.e., oxidized sulfur), although the hydration state cannot be constrained. In no case is there an excess of SO3 over available cations (i.e., no evidence for elemental sulfur), and Fe sulfide (pyrite) has been detected in only one Gusev sample. The presence of both high-SiO2 (and low total iron and SO3) and high SO3 (and high total iron as ferric sulfate) can be accommodated by a two-step geochemical model developed with the Geochemist's Workbench. (1) Step 1 is anoxic acid sulfate leaching of Martian basalt at high water-to rock ratios (greater than 70). The result is a high-SiO2 residue0, and anoxic conditions are required to solubilize Fe as Fe(2+). (2) Step 2 is the oxic precipitation of sulfate salts from the leachate. Oxic conditions are required to produce the high concentrations of ferric sulfate with minor Mg-sulfates and no detectable Fe(2+)-sulfates.

Iron Mineralogy and Aqueous Alteration on Mars from the MER Moessbauer Spectrometers. Chapter 15

NASA Technical Reports Server (NTRS)

Morris, Richard V.; Klingelhoefer, Goestar

2007-01-01

The twin Mars Exploration Rovers Spirit (Gusev crater) and Opportunity (Meridiani Planum) used MIMOS II Moessbauer spectrometers to analyze martian surface materials in the first application of extraterrestrial Moessbauer spectroscopy. The instruments acquired spectra that identified the speciation of Fe according to oxidation state, coordination state, and mineralogical composition and provided quantitative information about the distribution of Fe among oxidation states, coordination states, and Fe-bearing phases. A total of 12 unique Fe-bearing phases were identified: Fe(2+) in olivine, pyroxene, and ilmenite; Fe(2+) and Fe(3+) in magnetite and chromite; Fe(3+) in nanophase ferric oxide (npOx), hematite, goethite, jarosite, an unassigned Fe3+ sulfate, and an unassigned Fe(3+) phase associated with jarosite; and Fe(0) in kamacite. Weakly altered basalts at Gusev crater (SO3 = 2.5 +/- 1.4 wt.% and Fe(3+)/Fe(sub T) = 0.24 +/- 0.11) are widespread on the Gusev plains and occur in less abundance on West Spur and Husband Hill in the Columbia Hills. Altered low-S rocks (SO3 = 5.2 +/- 2.0 wt.% and Fe(3+)/Fe(sub T) = 0.63 +/- 0.18) are the most common type of rock in the Columbia Hills. Ilm-bearing, weakly altered basalts were detected only in the Columbia Hills, as was the only occurrence of chromite in an altered low-S rock named Assemblee. Altered high-S rocks (SO3 > 14.2 wt.% and Fe(3+)/Fe(sub T) = 0.83 +/- 0.05) are the outcrop rocks of the ubiquitous Burns formation at Meridiani Planum. Two Fe(0)-bearing rocks at Meridiani Planum (Barberton and Heat Shield Rock) are meteorites. Laguna Class soil is weakly altered (SO3 = 6 +/- 2 wt.% and Fe(3+)/Fe(sub T) = 0.29 +/- 0.08) and widely distributed at both Gusev crater and Meridiani Planum, implying efficient global mixing processes or a global distribution of precursor rocks with comparable Fe mineralogical compositions. Paso Robles Class soil is heavily altered (SO3 approx. 31 wt.% and Fe(3+)/Fe(sub T) = 0.83 +/- 0.05), is relatively uncommon, and occurs as subsurface deposits in the Columbia Hills. Berry Class soil is also heavily altered (SO3 = 5 +/- 1 wt.% and Fe(3+)/Fe(sub T) = 0.60 +/- 0.13) and occurs at Meridiani Planum as lag deposits, at the crests of aeolian bedforms, and as isolated pockets on outcrop surfaces. Magnetite is identified as the strongly magnetic component in martian soil. Jarosite (in the Burns outcrop at Meridiani Planum) and goethite (in Clovis Class rocks at Gusev crater) are mineralogical markers for aqueous processes because they contain the hydroxide anion (OH(-)) as an essential part of their structure. Each yields approx.10 wt.% H2O upon dehydroxylation. The presence of Fe sulfates on opposite sides of Mars is evidence that aqueous processes under acid sulfate conditions are or were common. Except for Independence Class rocks in the Columbia Hills, the overall Fe mineralogical compositions and similar basaltic bulk chemical compositions (calculated with respect to S = Cl = 0) of the population of altered rocks analyzed by MER imply isochemical alteration of basaltic precursors at low water-to-rock ratios.

Physics Division annual review, 1 April 1980-31 March 1981

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1982-06-01

Progress in nuclear physics research is reported in the following areas: medium-energy physics (pion reaction mechanisms, high-resolution studies and nuclear structure, and two-nucleon physics with pions and electrons); heavy-ion research at the tandem and superconducting linear accelerator (resonant structure in heavy-ion reactions, fusion cross sections, high angular momentum states in nuclei, and reaction mechanisms and distributions of reaction strengths); charged-particle research; neutron and photonuclear physics; theoretical physics (heavy-ion direct-reaction theory, nuclear shell theory and nuclear structure, nuclear matter and nuclear forces, intermediate-energy physics, microscopic calculations of high-energy collisions of heavy ions, and light ion direct reactions); the superconducting linac; acceleratormore » operations; and GeV electron linac. Progress in atomic and molecular physics research is reported in the following areas: dissociation and other interactions of energetic molecular ions in solid and gaseous targets, beam-foil research and collision dynamics of heavy ions, photoionization- photoelectron research, high-resolution laser rf spectroscopy with atomic and molecular beams, moessbauer effect research, and theoretical atomic physics. Studies on interactions of energetic particles with solids are also described. Publications are listed. (WHK)« less

To the problem about the origin of lunar maria and continents (Moessbauer investigations)

NASA Technical Reports Server (NTRS)

Malysheva, T. V.

1977-01-01

A comparative study of Mossbauer spectra of regolith returned by the Luna 16 and Luna 20 spacecraft is presented. The Mossbauer spectra of the mare regolith differs significantly for all fractions from the spectra for the same fractions of continental regolith. The total quantity of iron is 1.85 times greater in the mare regolith. There is 2.4 times less olivine in the mare region than in the continental region. The pyroxene component of the mare regolith is less homogeneous in composition (contains more augite and glass) and is present in larger quantities. Ilmenite was found only in the mare regolith. In the continental region, the predominant titanium-containing phase is ulvospinel. The mare regolith contains more metallic iron, which is more finely dispersed and contains less nickel. Troilite is found in the maria region. Based on these differences, it is concluded that the formation of continental rocks occurred at an earlier stage of crystallization from the melt and at higher temperatures and higher partial pressures of oxygen. The mare basalts crystallized from a more reduced magma, apparently in a later process.

Modification of local order in FePd films by low energy He{sup +} irradiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Merkel, D. G.; Tancziko, F.; Sajti, Sz.

2008-07-01

Owing to their strong perpendicular magnetic anisotropy, FePd, CoPd, and their Co(Fe)Pt counterparts are candidate materials for ultrahigh density magnetic recording. The stability and magnetic properties of such films are largely dependent on the orientation and local distribution of the L1{sub 0} FePd phase fraction. Therefore, the formation and transformation of the L1{sub 0} phase in such thin films have been the subject of continued interest. Highly ordered epitaxial FePd(001) thin films (with an L1{sub 0} phase fraction of 0.81) were prepared by molecular-beam epitaxy on a MgO(001) substrate. The effect of postgrown room temperature, 130 keV He{sup +} irradiationmore » was investigated at fluences up to 14.9x10{sup 15} ions/cm{sup 2}. X-ray diffraction and conversion electron Moessbauer spectroscopy revealed that with increasing fluence, the L1{sub 0} FePd phase decomposes into the face centered cubic phase with random Fe and Pd occupation of the sites. A partially ordered local environment exhibiting a large hyperfine magnetic field also develops. Upon He{sup +} irradiation, the lattice parameter c of the FePd L1{sub 0} structure increases and the long range order parameter S steeply decreases. The Fe-Fe nearest-neighbor coordination in the Fe-containing environments increases on average from Fe{sub 47}Pd{sub 53} to Fe{sub 54}Pd{sub 46}, indicating a tendency of formation iron-rich clusters. The equilibrium parameters corresponding to the equiatomic L1{sub 0} phase were found at different fluences by conversion electron Moessbauer spectroscopy and by x-ray diffraction a difference, from which a plane-perpendicular compressive stress and a corresponding in-plane tensile stress are conjectured. The steep increase in the interface roughness above 7.4x10{sup 15} ions/cm{sup 2} is interpreted as a percolation-type behavior related to the high diffusion anisotropy in the L1{sub 0} phase.« less

Fast dynamic electron transfer along infinite anion-cation chains in technetium and rhenium acido clusters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Antipov, B.G.; Kryuchkov, S.V.; Grigor`ev, M.S.

1995-09-01

New technetium and rhenium compounds with ferricenium cations - [Fe(C{sub 5}H{sub 5}){sub 2}]{sub 3}[Tc{sub 6}I{sub 14}], [Fe(C{sub 5}H{sub 5}){sub 2}]{sub 3}[Tc{sub 6}Cl{sub 14}], [Fe(C{sub 5}H{sub 5}){sub 2}]{sub 2}[Tc{sub 8}Br{sub 14}], and [Fe(C{sub 5}H{sub 5}){sub 2}]{sub 2}[Re{sub 2}Br{sub 8}] - are synthesized and identified. The compounds are characterized by the methods of static magnetic susceptibility and differential scanning calorimetry; solid-state conductivity measurements; and IR, EPR, {sup 57}Fe Moessbauer, and X-ray photoelectron spectroscopic data. These data are compared with the physicochemical characteristics of ferricenium pertechnetate and hexachlorotechnetate, as well as of a number of reference technetium and rhenium compounds containing the samemore » anions but different cations. The structure of [Fe(C{sub 5}H{sub 5}){sub 2}]{sub 3}[Tc{sub 6}I{sub 14}] is determined by X-ray diffraction analysis of a single crystal [space group P6/m, a = 15.34(2), c = 12.70(1) {angstrom}]. The structures of the remaining compounds were confirmed by comparing their spectroscopic properties with corresponding properties of compounds with known composition and structure. None of the compounds with ferricenium cations exhibit covalent or other localized bonds between anions and cations. However, the physicochemical properties of these compounds indicate the occurrence of a fast dynamic electron transfer along infinite anion-cation chains. Compounds [Fe(C{sub 5}H{sub 5}){sub 2}]{sub 3}[Tc{sub 6}Cl{sub 14}] and [Fe(C{sub 5}H{sub 5}){sub 2}]{sub 2}[Tc{sub 8}Br{sub 14}] were found to exhibit a new phenomenon of X-ray-induced low-temper ature high-energy electron emission.« less

Miniaturised Space Payloads for Outdoor Environmental Applications

NASA Astrophysics Data System (ADS)

de Souza, P. A.

2012-12-01

The need for portable, robust and acurate sensors has increased in recent years resulting from industrial and environmental needs. This paper describes a number of applications of engineering copies of those Moessbauer spectrometers (MIMOS II) used by Mars Exploration Rovers, and the use of portable XRF spectrometers in the analysis of heavy metals in sediments. MIMOS II has been applied in the characterisation of Fe-bearing phases in airborne particles in industrialised urban centres, The results have allowed an identification of sources or air pollution in near-real-time. The results help to combine production parameters with pollution impact in the urban area. MIMOS II became a powerful tool because its constructive requirements to flight has produced a robust, power efficient, miniaturised, and light. On the limitation side, the technique takes sometime to produce a good result and the instrument requires a radioactive source to operate. MIMOS II Team has reported a new generation of this instrument incorporating a XRF spectrometer using the radioactive source to generate fluorescence emissions from sample. The author, and its research group, adapted a portable XRF spectrometer to an autonomous underwater vehicle (AUV) and conducted heavy metals survey in sediments across the Derwent Estuary in Tasmania, Australia. The AUV lands on suitable locations underwater, makes the chemical analysis and decide based on the result to move to a closer location, should high concentration of chemicals of interest be found, or to another distant location otherwise. Beyond environmental applications, these instruments were applied in archaeology and in industrial process control.oessbauer spectra recorded on airborne particles (Total Suspended Particles) collected at Ilha do Boi, VItoria, ES, Brazil. SIRO's Autonomous Underwater Vehicle carring a miniaturised XRF spectrometer for underwater chemistry. Students involved in this Project: Mr Jeremy Breen and Mr Andrew Davie. Collaborators: Dr. Greg Timms (CSIRO) and Dr. Robert Ollington (UTAS). This AUV us 1.2m long.

Structural and magnetic study of Al{sup 3+} doped Ni{sub 0.75}Zn{sub 0.25}Fe{sub 2−x}Al{sub x}O{sub 4} nanoferrites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, L.; Rai, B.K.; Mishra, S.R.

2015-05-15

Graphical abstract: Hyperfine field of individual sites (inset) and weighted average hyperfine field as a function of Al{sup 3+} content for Ni{sub 0.75}Zn{sub 0.25}Fe{sub 2−x}Al{sub x}O{sub 4}. - Highlights: • Grain size reduction with Al{sup 3+} substitution. • Preferred occupancy of Al{sup 3+} at B site for higher Al{sup 3+} content. • Reduction in Ms, Tc, and hyperfine field with increasing Al{sup 3+} content. • Size dependent variation in coercivity. • Changes in isomer shift due to competing effect of volume and substitution. - Abstract: Nanostructured Al{sup 3+} doped Ni{sub 0.75}Zn{sub 0.25}Fe{sub 2−x}Al{sub x}O{sub 4} (x = 0.0, 0.2, 0.4,more » 0.6, 0.8, and 1.0) ferrites were synthesized via the wet chemical method. X-ray diffraction, transmission electron microscopy, and magnetization measurements have been used to investigate the structural and magnetic properties of spinel ferrites calcined at 950 °C. With the doping of Al{sup 3+}, the particle size of Ni{sub 0.75}Zn{sub 0.25}Fe{sub 2−x}Al{sub x}O{sub 4} first increased to 47 nm at x = 0.4 and then decreased down to 37 nm at x = 1. The main two absorption bands in IR spectra were observed around 600 cm{sup −1} and 400 cm{sup −1} corresponding to stretching vibration of tetrahedral and octahedral group Fe{sup 3+}–O{sup 2−}. Saturation magnetization and hyperfine field values decreased linearly with Al{sup 3+} due to magnetic dilution and the relative strengths of Fe–O–Me (Me = Fe, Ni, Zn, and Al) superexchanges. The coercive field showed an inverse dependence on ferrite particle size with minimum value of 82 Oe for x = 0.4. A continuous drop in Curie temperature was observed with the Al{sup 3+} substitution. From the Moessbauer spectral analysis and X-ray diffraction analysis, it is deduced that Al{sup 3+} for x < 0.4 has no obvious preference for either tetrahedral or octahedral site but has a greater preference for the B site for x > 0.4. In nutshell the study presents detailed structural and magnetic, and Moessbauer analysis of Ni{sub 0.75}Zn{sub 0.25}Fe{sub 2−x}Al{sub x}O{sub 4} ferrites.« less

Keepers of the Hematite

NASA Technical Reports Server (NTRS)

2004-01-01

This figure shows spectra taken by the Mars Exploration Rover Opportunity's Moessbauer spectrometer at various spots in 'Eagle Crater.' From top to bottom, the spectra represent soil measurements taken from the center of the crater and out to the rim. The top spectrum taken on sol 56 near the center of the crater shows a basaltic mineral composition and only minor amounts of hematite. Basalts are volcanic minerals and hematite is an iron-bearing mineral often formed in water. Moving closer to the rim, the spectra show increasing amounts of hematite with the 'Punaluu' site containing the highest amounts seen to date on Mars. Only minor basaltic components are seen in this sample.

The corresponding microscopic image of Punaluu shows a high density of 'blueberries,' indicating that these sphere-like grains are responsible for the observed high levels of hematite.

The Trench Throws a Dirt Clod at Scientists

NASA Technical Reports Server (NTRS)

2004-01-01

This picture, obtained by the microscopic imager on NASA's Opportunity rover during sol 24, February 17 PST, shows soil clods exposed in the upper wall of the trench dug by Opportunity's right front wheel on sol 23. The clods were not exposed until the trench was made. The presence of soil clods implies weak bonding between individual soil grains. The chemical agent or mineral that causes the dirt to bind together into a clod, which scientists call the 'bonding agent,' is currently unknown. Moessbauer and alpha particle X-ray spectrometer measurements of this spot, planned for sol 25, might help explain the bonding, which would ultimately help the rover team understand how geological processes vary across the red planet. In any case, the bonds between soil grains here cannot be very strong because the wheel dug down through this layer with little trouble.

Effect of substitutions and defects in half-Heusler FeVSb studied by electron transport measurements and KKR-CPA electronic structure calculations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jodin, L.; Tobola, J.; Pecheur, P.

2004-11-01

The structural and electron transport properties of the pure and Co-, Ti-, and Zr-substituted FeVSb half-Heusler phases have been investigated using x-ray diffraction, Moessbauer spectroscopy, and Electron Probe Microscopy Analysis as well as resistivity, thermopower, and Hall effect measurements in the 80-900 K temperature range. In a parallel study, the electronic structures of FeVSb and the aforementioned alloys were calculated using the Korringa-Kohn-Rostoker method with the coherent potential approximation (KKR-CPA) in the LDA framework. The electronic densities of states and dispersion curves were obtained. The crystal structure stability and site preference analysis were addressed using total energy computations. Most ofmore » these experimental results correspond to electronic structure computations only if they take into account extra crystal defects such as antisite defects or vacancies present to various extents in the samples. Indeed a remarkable variation of KKR-CPA density of states occurring both in FeVSb and FeV{sub 1-x}Zr{sub x}Sb including defects may explain why FeVSb is not fully semiconducting as well as why there is a change of the thermopower sign in the FeV{sub 1-x}Zr{sub x}Sb versus x content.« less

Radiation detector

DOEpatents

Fultz, B.T.

1980-12-05

Apparatus is provided for detecting radiation such as gamma rays and x-rays generated in backscatter Moessbauer effect spectroscopy and x-ray spectrometry, which has a large window for detecting radiation emanating over a wide solid angle from a specimen and which generates substantially the same output pulse height for monoenergetic radiation that passes through any portion of the detection chamber. The apparatus includes a substantially toroidal chamber with conductive walls forming a cathode, and a wire anode extending in a circle within the chamber with the anode lying closer to the inner side of the toroid which has the least diameter than to the outer side. The placement of the anode produces an electric field, in a region close to the anode, which has substantially the same gradient in all directions extending radially from the anode, so that the number of avalanche electrons generated by ionizing radiation is independent of the path of the radiation through the chamber.

Petrography and Origin of the Unique Achondrite GRA 06128 and 06129: Preliminary Results

NASA Technical Reports Server (NTRS)

Treiman, A. H.; Morris, R. V.; Kring, D. A.; Mittlefehldt, D. W.; Jones, J. H.

2008-01-01

GRA 06128 & 06129 are paired achondrites [1], with unique mineral proportions (75% oligoclase), mineral compositions, and oxygen isotope ratios. They appear to represent alkalic igneous rock from a hitherto unsampled differentiated parent body, modified significantly by thermal and shock metamorphism. Samples and Methods: Bulk samples were examined at JSC during splitting for consortium analyses. Microscope and BSE images here are on thick section GRA06128,40. Chemical analyses of minerals were acquired at Johnson Space Center with the Cameca SX100, operated at 15 kV. Feldspar was analyzed with a defocused 5 micron beam @ 5 nA; other minerals were analyzed with a focused beam @ 20 nA. Moessbauer spectra were obtained at ARES, JSC [2]. Intrinsic radioactivity was measured in the low-level counting facility at ARES JSC [3]. An estimated abundance of Al-26 of approx. 70 dpm/kg is within the range determined for eucrites.

Magnetic phase composition of strontium titanate implanted with iron ions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dulov, E.N., E-mail: evgeny.dulov@ksu.ru; Ivoilov, N.G.; Strebkov, O.A.

2011-12-15

Highlights: Black-Right-Pointing-Pointer The origin of RT-ferromagnetism in iron implanted strontium titanate. Black-Right-Pointing-Pointer Metallic iron nanoclusters form during implantation and define magnetic behaviour. Black-Right-Pointing-Pointer Paramagnetic at room temperature iron-substituted strontium titanate identified. -- Abstract: Thin magnetic films were synthesized by means of implantation of iron ions into single-crystalline (1 0 0) substrates of strontium titanate. Depth-selective conversion electron Moessbauer spectroscopy (DCEMS) indicates that origin of the samples magnetism is {alpha}-Fe nanoparticles. Iron-substituted strontium titanate was also identified but with paramagnetic behaviour at room temperature. Surface magneto-optical Kerr effect (SMOKE) confirms that the films reveal superparamagnetism (the low-fluence sample) or ferromagnetism (themore » high-fluence sample), and demonstrate absence of magnetic in-plane anisotropy. These findings highlight iron implanted strontium titanate as a promising candidate for composite multiferroic material and also for gas sensing applications.« less

Biomedical research applications of electromagnetically separated enriched stable isotopes

NASA Astrophysics Data System (ADS)

Lambrecht, R. M.

The current and projected annual requirements through 1985 for stable isotopes enriched by electromagnetic separation methods were reviewed for applications in various types of biomedical research: (1) medical radiosiotope production, labeled compounds, and potential radio-pharmaceuticals; (2) nutrition, food science, and pharmacology: (3) metallobiochemistry and environmental toxicology; (4) nuclear magnetic resonance, electron paramagnetic resonance, and moessbauer spectroscopy in biochemical, biophysical, and biomedical research; and (5) miscellaneous advances in radioactive and nonradioactive tracer technology. Radioisotopes available from commercial sources or routinely used in clinical nuclear medicine were excluded. Current requirements for enriched stable isotopes in biomedical research are not being satisfied. Severe shortages exist for Mg 26, Ca 43, Zn 70, Se 76, Se 77, Se 78, Pd 102, Cd 111, Cd 113, and Os 190. Many interesting and potentially important investigations in biomedical research require small quantities of specific elements at high isotopic enrichments.

Influence of the nature of the ligand on the structure and spectra of boron-containing iron(II) dioximates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pol'shin, E.V.; Trachevskii, V.V.; Tyukhtenko, S.I.

1987-11-01

The Moessbauer (/sup 57/Fe) and NMR (/sup 1/H, /sup 13/C, /sup 11/B) spectra of the macrobicyclic dioximates FeD/sub 3/(BF)/sub 2/, where H/sub 2/D stands for glyoxime, methylglyoxime, 1,2-cyclohexanedione dioxime (Nioxime), furildioxime, and benzil dioxime, have been investigated. The values of the isomer shifts for these compounds range from 0.31 to 0.37 mm/sec relative to sodium nitroprusside, and the Raman scattering ranges from 0.6 to 0.9 for the aliphatic oximes and is equal to approx. 0.2 for the aromatic oximes. The changes in the Raman scattering have been related to the angle of distortion of the trigonal prism. The greatest changesmore » in the /sup 13/C and /sup 1/H NMR spectra are observed for the atoms of the substituents.« less

Discovery of Carbonate-Rich Outcrops in the Gusev Crater Columbia Hills by the MER Rover Spirit

NASA Technical Reports Server (NTRS)

Morris, Richard V.; Ruff, Steven W.; Gellert, Ralf; Ming, Douglas W.; Arvidson, Raymond E.; Clark, Benton C.; Golden, Dadi C.; Siebach, Kirsten L.; Klingelhoefer, Goestar; Schroeder, Christian;

Layered Outcrops in Gusev Crater

NASA Technical Reports Server (NTRS)

2004-01-01

NASA's Mars Exploration Rover Spirit collected data on morphology, composition, and mineralogy of a rock nicknamed 'Tetl' using the microscopic imager, the alpha particle X-ray spectrometer, and the Moessbauer spectrometer before moving on. Scientists are discussing a suggestion that this rock outcrop and others on the 'West Spur' of the 'Columbia Hills' in Gusev Crater on Mars may contain evidence of graded bedding, in which alternate layers of sediment are either coarser or finer depending on the turbulence of the processes that deposited them. Such layers could be deposited by water circulating in rivers or lakes, volcanic ash settling on the surface, wind carrying fine-grained sediments, or a combination of these processes. This view is a mosaic of images that Spirit took with its microscopic imager on the rover's 272nd and 273rd martian days, or sols (Oct. 7 and 8, 2004). It has been enhanced to bring out details in the shadows without washing out sunlit areas. The section of rock shown here is approximately 17 centimeters (6.7 inches) wide.

Moessbauer spectra of ferrite catalysts used in oxidative dehydrogenation

NASA Technical Reports Server (NTRS)

Cares, W. R.; Hightower, J. W.

1971-01-01

Room temperature Mossbauer spectroscopy was used to examine bulk changes which occur in low surface area CoFe2O4 and CuFe2O4 catalysts as a result of contact with various mixtures of trans-2-butene and O2 during oxidative dehydrogenation reactions at about 420 C. So long as there was at least some O2 in the gas phase, the CoFe2O4 spectrum was essentially unchanged. However, the spectrum changed from a random spinel in the oxidized state to an inverse spinel as it was reduced by oxide ion removal. The steady state catalyst lies very near the fully oxidized state. More dramatic solid state changes occurred as the CuFe2O4 underwent reduction. Under severe reduction, the ferrite was transformed into Cu and Fe3O4, but it could be reversibly recovered by oxidation. An intense doublet located near zero velocity persisted in all spectra of CuFe2O4 regardless of the state of reduction.

Consortium study of the unusual H chondrite regolith breccia, Noblesville

NASA Technical Reports Server (NTRS)

Lipschutz, Michael E.; Wolf, Stephen F.; Vogt, Stephan; Michlovich, Edward; Lindstrom, Marilyn M.; Zolensky, Michael E.; Mittlefehldt, David W.; Satterwhite, Cecilia; Schultz, Ludolf; Loeken, Thomas

1993-01-01

The Noblesville meteorite is a genomict, regolith breccia (H6 clasts in H4 matrix). Moessbauer analysis confirms that Noblesville is unusually fresh, not surprising in view of its recovery immediately after its fall. It resembles 'normal' H4-6 chondrites in its chemical composition and induced thermoluminescence (TL) levels. Thus, at least in its contents of volatile trace elements, Noblesville differs from other H chondrite, class A regolith breccias. Noblesville's small pre-atmospheric mass and fall near solar maximum and/or its peculiar orbit (with perihelion less than 0.8 AU as shown by natural TL intensity) may partly explain its levels of cosmogenic radionuclides. Its cosmic ray exposure age of about 44 Ma is long, is equalled or exceeded by less than 3 percent of all H chondrites, and also differs from the 33 +/- 3 Ma mean exposure age peak of other H chondrite regolith breccias. While Noblesville is now among the chondritic regolithic breccias richest in solar gases, elemental ratios indicate some loss, especially of He, perhaps by impacts in the regolith that heated individual grains. While general shock-loading levels in Noblesville did not exceed 4 GPa, individual clasts record shock levels of 5-10 GPa, doubtless acquired prior to lithification of the whole-rock meteoroid.

a Moessbauer Effect and Fenske-Hall Molecular Orbital Study of the Electronic Properties of Organoiron Clusters.

NASA Astrophysics Data System (ADS)

Buhl, Margaret Linn

The electronic properties of trinuclear iron, tetranuclear iron butterfly, iron-cobalt, and iron-copper clusters have been studied experimentally at 78K by the Mossbauer effect and theoretically by Fenske-Hall molecular orbital calculations. The Mossbauer effect isomer shift is very sensitive to the differences in the iron s-electron densities in these clusters and, as expected, decreases as the sum of the iron 4s Mulliken population and the Clementi and Raimondi effective nuclear charge increases. The molecular orbital wave functions and the Mulliken atomic charges are used to calculate the electric field gradient at the metal nuclei and the iron Mossbauer effect quadrupole splittings. The valence contribution was found to be the major component of the electric field gradient in all the clusters studied. In general the calculated value of Delta E_ {Q} is larger than the observed value, as a result of neglect of the valence Sternheimer factor, R. The metal charge depends upon its electronegativity and upon the nature of its Lewis base ligands. The carbonyl ligand carbon charge becomes more positive as the metal electronegativity increases. The oxygen charge becomes more negative as the anionic cluster charge increases, and in so doing, yields the maximum anionic charge separation. The electronic properties of the terminal carbonyl ligands are similar to those of carbon monoxide, whereas the electronic properties of the bridging carbonyl ligands are similar to those of the carbonyl group found in aldehydes and ketones.

Relevance of supramolecular interactions, texture and lattice occupancy in the designer iron(II) spin crossover complexes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Naik, Anil D.; Tinant, Bernard; Muffler, Kai

New Fe{sup II} complexes of formula [Fe(3-Br-phen){sub 2}(NCS){sub 2}].Solvent (Solvent=0.5 CH{sub 3}OH (1), 2 CH{sub 2}Cl{sub 2} (2), desolvation of 2 (3), 0.5 CH{sub 3}COCH{sub 3} (4) and 0 (5)) have been synthesized. {sup 57}Fe Moessbauer and magnetic investigation reveal unique features atypical of classic [Fe(phen){sub 2}(NCS){sub 2}] polymorphs. Complex 1, prepared by precipitation in MeOH, undergoes upon cooling below room temperature an incomplete and gradual thermally induced spin conversion, while 4 prepared by an extraction method remains mostly in the low-spin state. The non solvated compounds 3 and 5, display a more abrupt spin crossover on cooling around T{submore » 1/2}=175 K and T{sub 1/2}=198 K, respectively. Defects/soft lattice inclusion due to different methods of material synthesis, extent of aging, reaction medium and associated solvent molecules have enormous influence on the particle size and magnetic properties of these complexes. Scanning electron micrographs helps to establish a logical relationship among methods employed for synthesis, texture of materials and their effect on magnetic properties. The crystal structure of 2 determined in the monoclinic space group P2/c (100 K) reveals a mononuclear complex consisting of a distorted FeN{sub 6} octahedron in the low-spin state, constructed from two 3-bromo-1, 10-phenanthroline and two isothiocyanato anions in cis position. Intermolecular interactions between mononuclear units of the S...Br, S...C(H) and pi-pi type afford a 2D supramolecular network. DFT calculations for the single molecule 2 reveals an energy difference between high-spin and low-spin isomers of 7 kJ/mol suggesting a slight destabilization of the low-spin state compared to [Fe(phen){sub 2}(NCS){sub 2}]. Normal co-ordinate analysis was also carried out for 3 and compared with experimental temperature dependent Raman spectra for 5. - Graphical abstract: New Fe{sup II} complexes of formula [Fe(3-Br-phen){sub 2}(NCS){sub 2}].Solvent have been synthesized by precipitation (1) and extraction (4) methods. {sup 57}Fe Moessbauer and magnetic investigation reveal unique features atypical of classic [Fe(phen){sub 2}(NCS){sub 2}] polymorphs. Complex 1, undergoes upon cooling below room temperature an incomplete and gradual thermally induced spin conversion, while 4 remains mostly in the low-spin state. Role of supramolecular interactions, particles size, lattice solvents have profound influence on magnetic properties.« less

Topotactic redox chemistry of NaFeAs in water and air and superconducting behavior with stoichiometry change.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Todorov, I.; Chung, D. Y.; Claus, H.

2010-07-13

We report experimental evidence that shows superconductivity in NaFeAs occurs when it is Na deficient. The oxidation of NaFeAs progresses differently in water and in air. In water the material oxidizes slowly and slightly retaining the original anti-PbFCl structure. In air NaFeAs oxidizes topotactically quickly and extensively transforming to the ThCr{sub 2}Si{sub 2} structure type. Water acts as a mild oxidizing agent on the FeAs layer by extracting electrons and Na{sup +} cations from the structure, while oxidation in air is more extensive and leads to change in structure type from NaFeAs to NaFe{sub 2}As{sub 2}. The superconducting transition temperaturemore » moves dramatically during the oxidation process. Exposed to water for an extended time period NaFeAs shows a substantial increase in T{sub c} up to 25 K with contraction of unit cell volume. NaFe{sub 2}As{sub 2}, the air oxidized product, shows T{sub c} of 12 K. We report detailed characterization of the redox chemistry and transformation of NaFeAs in water and air using single crystal and powder X-ray diffraction, magnetization studies, transmission electron microscopy, Moessbauer spectroscopy, pOH and elemental analysis.« less

Effect of some metal chlorides on the transformation of pyrite to pyrrhotite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shiley, R.H.; Konopka, K.L.; Hinckley, C.C.

1982-08-01

Samples of the iron-sulfide mineral pyrrhotite were prepared using a procedure designed to closely model the pyrite-to-pyrrhotite conversion that occurs during coal-conversion processing. Pyrite mixed with graphite converts to mixtures of monoclinic and hexagonal pyrrhotite when heated at 500C for 4.5 hours, and an iron-rich pyrrhotite (Fe10S11) forms at 600 to 700C. In addition to temperature effects, the pyrrhotites formed from pyrite in graphite are also dependent on additives or impurities in the form of metal salts. The pyrrhotites used in this study were prepared in the presence of selected transition metal chlorides: PdCl2, NiCl2, CoCl2, ZnCl2, MoCl5, and ZrCl4.more » When these metal salts were used, pyrrhotites with an increased number of iron vacancies were produced. For example, in the presence of ZrCl4 at temperatures as high as 700C, a pyrrhotite was produced that exhibited Moessbauer magnetic-splitting values characteristic of pyrrhotite with a high number of iron vacancies (iron-poor). These pyrrhotites were then converted to troilite at 400C in the presence of CO and H2; and this troilite is an active catalyst for the Fischer-Tropsch synthesis, alkene hydrogenation, the Boudouard reaction, the water-gas shift reaction, and the hydrodesulfurization of organic sulfur compounds.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Theil, Elizabeth C.; Department of Nutritional Science and Toxicology, University of California, Berkeley, CA 94720

Ferritins are protein nanocages that use iron and oxygen chemistry to concentrate iron and trap dioxygen or hydrogen peroxide in biominerals of hydrated ferric oxides, 5-8 nm in diameter, inside the cages. The proteins are found in nature from archea to humans. Protein catalytic sites are embedded in the protein cage and initiate mineralization by oxido-reduction of ferrous ions and dioxygen or hydrogen peroxide to couple two iron ions through a peroxo bridge, followed by decay to diferric oxo/hydroxyl mineral precursors; ferritin protein subdomains that fold/unfold independently of the protein cage control recovery of ferrous ions from the mineral. Earlymore » EXAFS (1978) was extremely useful in defining the ferritin mineral. More recent use of rapid freeze quench (RFQ) EXAFS spectroscopies, coupled with RFQ Moessbauer, Resonance Raman and rapid mixing UV-vis spectroscopy, have identified and characterized unusual ferritin protein catalytic intermediates and mineral precursors. EXAFS spectroscopy can play an important role in the future understanding of protein catalysis in metalloproteins such as ferritin, ribonucleotide reductase and methane monooxygenases. Needed are instrumentation improvements that will provide rapid-scan fluorescence spectra with high signal/noise ratios.« less

On the fine structure of meteoritical taenite/tetrataenite and its interpretation

NASA Astrophysics Data System (ADS)

Albertsen, J. F.; Nielsen, H. P.; Buchwald, V. F.

1983-04-01

TEM, electron microprobe, and Moessbauer spectroscopy are used in investigating taenite fields from several meteorites. A delicate pattern of antiphase domains is revealed in the tetrataenite, as is the presence of low-Ni taenite at the antiphase boundaries in what was hitherto believed to be pure tetrataenite. The observations suggest that the 'cloudy taenite' (cloudy zone II) was formed by a magnetically induced spinodal decomposition of the metastable taenite during slow cooling below 400 C. It is thought likely that decompositin occurs when the Curie temperature of the alloy changes rapidly with composition, as it does in f.c.c. iron-nickel alloys containing approximately 28-43 percent Ni (wt pct). The large contribution to Gibbs free energy from magnetic ordering leads to inflections in the Gibbs free energy curve, making the alloy unstable with regard to decomposition, in this case into a magnetically and atomically ordered Ni-rich alloy plus a magnetically and atomically disordered Ni-poor alloy. The model accounts well for the structure and composition of the two phases in the cloudy taenite.

A Comparison of Multivariate and Pre-Processing Methods for Quantitative Laser-Induced Breakdown Spectroscopy of Geologic Samples

NASA Technical Reports Server (NTRS)

Anderson, R. B.; Morris, R. V.; Clegg, S. M.; Bell, J. F., III; Humphries, S. D.; Wiens, R. C.

2011-01-01

The ChemCam instrument selected for the Curiosity rover is capable of remote laser-induced breakdown spectroscopy (LIBS).[1] We used a remote LIBS instrument similar to ChemCam to analyze 197 geologic slab samples and 32 pressed-powder geostandards. The slab samples are well-characterized and have been used to validate the calibration of previous instruments on Mars missions, including CRISM [2], OMEGA [3], the MER Pancam [4], Mini-TES [5], and Moessbauer [6] instruments and the Phoenix SSI [7]. The resulting dataset was used to compare multivariate methods for quantitative LIBS and to determine the effect of grain size on calculations. Three multivariate methods - partial least squares (PLS), multilayer perceptron artificial neural networks (MLP ANNs) and cascade correlation (CC) ANNs - were used to generate models and extract the quantitative composition of unknown samples. PLS can be used to predict one element (PLS1) or multiple elements (PLS2) at a time, as can the neural network methods. Although MLP and CC ANNs were successful in some cases, PLS generally produced the most accurate and precise results.

MER Telemetry Processor

NASA Technical Reports Server (NTRS)

Lee, Hyun H.

2012-01-01

MERTELEMPROC processes telemetered data in data product format and generates Experiment Data Records (EDRs) for many instruments (HAZCAM, NAVCAM, PANCAM, microscopic imager, Moessbauer spectrometer, APXS, RAT, and EDLCAM) on the Mars Exploration Rover (MER). If the data is compressed, then MERTELEMPROC decompresses the data with an appropriate decompression algorithm. There are two compression algorithms (ICER and LOCO) used in MER. This program fulfills a MER specific need to generate Level 1 products within a 60-second time requirement. EDRs generated by this program are used by merinverter, marscahv, marsrad, and marsjplstereo to generate higher-level products for the mission operations. MERTELEPROC was the first GDS program to process the data product. Metadata of the data product is in XML format. The software allows user-configurable input parameters, per-product processing (not streambased processing), and fail-over is allowed if the leading image header is corrupted. It is used within the MER automated pipeline. MERTELEMPROC is part of the OPGS (Operational Product Generation Subsystem) automated pipeline, which analyzes images returned by in situ spacecraft and creates level 1 products to assist in operations, science, and outreach.

Lunar and Planetary Science XXXV: Weird Martian Minerals: Complex Mars Surface Processes

NASA Technical Reports Server (NTRS)

2004-01-01

The session "Complex Mars Surface" included the following reports:A Reappraisal of Adsorbed Superoxide Ion as the Cause Behind the Reactivity of the Martian Soils; Sub-Surface Deposits of Hydrous Silicates or Hydrated Magnesium Sulfates as Hydrogen Reservoirs near the Martian Equator: Plausible or Not?; Thermal and Evolved Gas Analysis of Smectites: The Search for Water on Mars; Aqueous Alteration Pathways for K, Th, and U on Mars; Temperature Dependence of the Moessbauer Fraction in Mars-Analog Minerals; Acid-Sulfate Vapor Reactions with Basaltic Tephra: An Analog for Martian Surface Processes; Iron Oxide Weathering in Sulfuric Acid: Implications for Mars; P/Fe as an Aquamarker for Mars; Stable Isotope Composition of Carbonates Formed in Low-Temperature Terrestrial Environments as Martian Analogs; Can the Phosphate Sorption and Occlusion Properties Help to Elucidate the Genesis of Specular Hematite on the Mars Surface?; Sulfate Salts, Regolith Interactions, and Water Storage in Equatorial Martian Regolith; Potential Pathways to Maghemite in Mars Soils: The Key Role of Phosphate; and Mineralogy, Abundance, and Hydration State of Sulfates and Chlorides at the Mars Pathfinder Landing Site.

Looking for Changes in Soil over Time

NASA Technical Reports Server (NTRS)

2006-01-01

The grinding teeth have worn away on the rock abrasion tool of NASA's Mars Exploration Rover Spirit (after exposing interiors of five time more rock targets than its design goal of three rocks) but the tool still has useful wire bristles for brushing targets. In this image, a figure-eight-like imprint in the Martian soil marks the spot where Spirit has begun examining subsurface deposits layer by layer. The circular indentations resulted from brushing by the rock abrasion tool, one of several instruments on the rover's robotic arm. As an effective brushing tool it is now fulfilling a soil profiling experiment on a target called 'Progress.'

The experiment is a multi-step process of carefully brushing away fine layers of soil and then using the Moessbauer and alpha particle X-ray spectrometers, microscopic imager, and panoramic camera to examine the exposed surfaces during the long Martian winter.

This view is a mosaic of exposures taken by Spirit's microscopic imager during the rover's 830th Martian day (May 4, 2006). The total area shown is about 6 centimeters (2.4 inches) square.

Gathering pipeline methane emissions in Fayetteville shale pipelines and scoping guidelines for future pipeline measurement campaigns

DOE PAGES

Zimmerle, Daniel J.; Pickering, Cody K.; Bell, Clay S.; ...

2017-11-24

Gathering pipelines, which transport gas from well pads to downstream processing, are a sector of the natural gas supply chain for which little measured methane emissions data are available. This study performed leak detection and measurement on 96 km of gathering pipeline and the associated 56 pigging facilities and 39 block valves. The study found one underground leak accounting for 83% (4.0 kg CH 4/hr) of total measured emissions. Methane emissions for the 4684 km of gathering pipeline in the study area were estimated at 402 kg CH 4/hr [95 to 1065 kg CH 4/hr, 95% CI], or 1% [0.2%more » to 2.6%] of all methane emissions measured during a prior aircraft study of the same area. Emissions estimated by this study fall within the uncertainty range of emissions estimated using emission factors from EPA's 2015 Greenhouse Inventory and study activity estimates. While EPA's current inventory is based upon emission factors from distribution mains measured in the 1990s, this study indicates that using emission factors from more recent distribution studies could significantly underestimate emissions from gathering pipelines. To guide broader studies of pipeline emissions, we also estimate the fraction of the pipeline length within a basin that must be measured to constrain uncertainty of pipeline emissions estimates to within 1% of total basin emissions. The study provides both substantial insight into the mix of emission sources and guidance for future gathering pipeline studies, but since measurements were made in a single basin, the results are not sufficiently representative to provide methane emission factors at the regional or national level.« less

Gathering pipeline methane emissions in Fayetteville shale pipelines and scoping guidelines for future pipeline measurement campaigns

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zimmerle, Daniel J.; Pickering, Cody K.; Bell, Clay S.

Gathering pipelines, which transport gas from well pads to downstream processing, are a sector of the natural gas supply chain for which little measured methane emissions data are available. This study performed leak detection and measurement on 96 km of gathering pipeline and the associated 56 pigging facilities and 39 block valves. The study found one underground leak accounting for 83% (4.0 kg CH 4/hr) of total measured emissions. Methane emissions for the 4684 km of gathering pipeline in the study area were estimated at 402 kg CH 4/hr [95 to 1065 kg CH 4/hr, 95% CI], or 1% [0.2%more » to 2.6%] of all methane emissions measured during a prior aircraft study of the same area. Emissions estimated by this study fall within the uncertainty range of emissions estimated using emission factors from EPA's 2015 Greenhouse Inventory and study activity estimates. While EPA's current inventory is based upon emission factors from distribution mains measured in the 1990s, this study indicates that using emission factors from more recent distribution studies could significantly underestimate emissions from gathering pipelines. To guide broader studies of pipeline emissions, we also estimate the fraction of the pipeline length within a basin that must be measured to constrain uncertainty of pipeline emissions estimates to within 1% of total basin emissions. The study provides both substantial insight into the mix of emission sources and guidance for future gathering pipeline studies, but since measurements were made in a single basin, the results are not sufficiently representative to provide methane emission factors at the regional or national level.« less

Odor and odorous chemical emissions from animal buildings: Part 3 - chemical emissions

USDA-ARS?s Scientific Manuscript database

This study was an add-on study to the National Air Emission Monitoring Study (NAEMS). The objective of this study was to measure odor emissions and corresponding concentrations and emissions of target odorous gases. Odor and odorous gas measurements at four NAEMS sites (dairy barns in Wisconsin-WI5B...

Odor and odorous chemical emissions from animal buildings: Part 3. Chemical emissions

USDA-ARS?s Scientific Manuscript database

The objective of this study was to measure the long-term odor emissions and corresponding concentrations and emissions of 20 odorous volatile organic compounds (VOCs). This study was an add-on study to the National Air Emission Monitoring Study (NAEMS). Odor and odorous gas measurements at four NAEM...

Moessbauer Study of Reduced Putidaredoxin in Zero and Intermediate Applied Fields.

NASA Astrophysics Data System (ADS)

Valentine, Mark

An ('57)Fe Mossbauer investigation of the reduced (S = 1/2) active center of the redox and effector protein, putidaredoxin, is reported. Putidaredoxin is a prototype of a 2Fe-2S protein; it functions as an electron shuttle in a bacterial enzyme system. Several 2Fe-2S proteins, including putidaredoxin, have already been subjected to numerous Mossbauer and magnetic resonance studies, but current understanding of the active center is still very incomplete, and the mechanism of electron transfer is not known. Previous Mossbauer experiments on reduced putidaredoxin, as on most Kramers systems, were restricted to the applied field range .01 - 4T. The intermediate field region 0 - .01T is included here, and a primary goal of this work is to demonstrate the feasibility of those experiments. The analysis of zero field spectra differs from that in applied fields in the following respects: (i) The spectra consist of 64 discrete lines. (ii) The average over all molecular orientations is done explicitly, not numerically. (iii) No generality is lost by taking the magnetic hyperfine terms for both sites to be symmetric and in their principal axis systems. (iv) The spectra are sensitive to weak coupling of S with nearby nuclear moments that become negligible as the applied field is increased. Skew-symmetric contributions to the magnetic hyperfine and electronic Zeeman interactions are often ignored in the literature without justification. Either g or A can be symmetrized by an S transformation, but both g and A can be simultaneously symmetrized if and only if the invariants. (DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI). are equal.

Emission Sectoral Contributions of Foreign Emissions to Particulate Matter Concentrations over South Korea

NASA Astrophysics Data System (ADS)

Kim, E.; Kim, S.; Kim, H. C.; Kim, B. U.; Cho, J. H.; Woo, J. H.

2017-12-01

In this study, we investigated the contributions of major emission source categories located upwind of South Korea to Particulate Matter (PM) in South Korea. In general, air quality in South Korea is affected by anthropogenic air pollutants emitted from foreign countries including China. Some studies reported that foreign emissions contributed 50 % of annual surface PM total mass concentrations in the Seoul Metropolitan Area, South Korea in 2014. Previous studies examined PM contributions of foreign emissions from all sectors considering meteorological variations. However, little studies conducted to assess contributions of specific foreign source categories. Therefore, we attempted to estimate sectoral contributions of foreign emissions from China to South Korea PM using our air quality forecasting system. We used Model Inter-Comparison Study in Asia 2010 for foreign emissions and Clean Air Policy Support System 2010 emission inventories for domestic emissions. To quantify contributions of major emission sectors to South Korea PM, we applied the Community Multi-scale Air Quality system with brute force method by perturbing emissions from industrial, residential, fossil-fuel power plants, transportation, and agriculture sectors in China. We noted that industrial sector was pre-dominant over the region except during cold season for primary PMs when residential emissions drastically increase due to heating demand. This study will benefit ensemble air quality forecasting and refined control strategy design by providing quantitative assessment on seasonal contributions of foreign emissions from major source categories.

Sulfur and iron speciation in gas-rich impact-melt glasses from basaltic shergottites determined by microXANES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sutton, S.R.; Rao, M.N.; Nyquist, L.E.

2008-04-28

Sulfur and iron K XANES measurements were made on GRIM glasses from EET 79001. Iron is in the ferrous state. Sulfur speciation is predominately sulfide coordination but is Fe coordinated in Lith B and, most likely, Ca coordinated in Lith A. Sulfur is abundantly present as sulfate near Martian surface based on chemical and mineralogical investigations on soils and rocks in Viking, Pathfinder and MER missions. Jarosite is identified by Moessbauer studies on rocks at Meridian and Gusev, whereas MgSO{sub 4} is deduced from MgO-SO{sub 3} correlations in Pathfinder MER and Viking soils. Other sulfate minerals such as gypsum andmore » alunogen/S-rich aluminosilicates and halides are detected only in martian meteorites such as shergottites and nakhlites using SEM/FE-SEM and EMPA techniques. Because sulfur has the capacity to occur in multiple valence states, determination of sulfur speciation (sulfide/sulfate) in secondary mineral assemblages in soils and rocks near Mars surface may help us understand whether the fluid-rock interactions occurred under oxidizing or reducing conditions. On Earth, volcanic rocks contain measurable quantities of sulfur present as both sulfide and sulfate. Carroll and Rutherford showed that oxidized forms of sulfur may comprise a significant fraction of total dissolved sulfur, if the oxidation state is higher than {approx}2 log fO{sub 2} units relative to the QFM buffer. Terrestrial samples containing sulfates up to {approx}25% in fresh basalts from the Galapagos Rift on one hand and high sulfide contents present in oceanic basalts on the other indicate that the relative abundance of sulfide and sulfate varies depending on the oxygen fugacity of the system. Basaltic shergottites (bulk) such as Shergotty, EET79001 and Zagami usually contain small amounts of sulfur ({approx}0.5%) as pyrrhotite. But, in isolated glass pockets containing secondary salts (known as GRIM glasses) in these meteorites, sulfur is present in high abundance ({approx}1-12%). To determine sulfur speciation (sulfide, sulfate or elemental sulfur) in these glasses, Gooding et al. and Burgess et al. carried out vacuum pyrolysis experiments on these GRIM glasses (also called Lith C) using quadrupole mass-spectrometric methods. They found that the evolved S-bearing gases from these samples consisted of both SO{sub 2} (from sulfate) and H{sub 2}S (from sulfide) in varying proportions. However, as mass-spectrometric studies do not provide details about spatial association of these S-species in these samples, we have studied the spatial distribution of sulfides and sulfates in GRIM glasses using sulfur K micro-XANES techniques in the present study. The microscale speciation of S may have important implications for the Rb-Sr isotope systematics of EET79001 Lith C glasses. In reference to oxidative weathering of surface basalts on Mars yielding secondary iron sulfates, Solberg and Burns examined a GRIM glass in EET79001 by Moessbauer spectroscopic techniques and showed that the percentage of Fe{sup 3+} in Lith C is <2%. They suggested that the Lith C contains very little Fe{sup 3+} despite the occurrence of oxidized sulfate in them, indicating that the conditions leading to the formation of these glasses were insufficiently oxidizing to produce Fe{sup 3+} from Fe{sup 2+} in these glasses. To understand the implications of these observations for the formation of the GRIM glasses, we determined the oxidation state of Fe in the GRIM glasses using Fe K micro-XANES techniques. The S and Fe K micro-XANES measurements were performed on thin sections from EET79001: 506 from Lith A and 507 from Lith B.« less

Black carbon emissions in Russia: A critical review

NASA Astrophysics Data System (ADS)

Evans, Meredydd; Kholod, Nazar; Kuklinski, Teresa; Denysenko, Artur; Smith, Steven J.; Staniszewski, Aaron; Hao, Wei Min; Liu, Liang; Bond, Tami C.

2017-08-01

This study presents a comprehensive review of estimated black carbon (BC) emissions in Russia from a range of studies. Russia has an important role regarding BC emissions given the extent of its territory above the Arctic Circle, where BC emissions have a particularly pronounced effect on the climate. We assess underlying methodologies and data sources for each major emissions source based on their level of detail, accuracy and extent to which they represent current conditions. We then present reference values for each major emissions source. In the case of flaring, the study presents new estimates drawing on data on Russia's associated petroleum gas and the most recent satellite data on flaring. We also present estimates of organic carbon (OC) for each source, either based on the reference studies or from our own calculations. In addition, the study provides uncertainty estimates for each source. Total BC emissions are estimated at 688 Gg in 2014, with an uncertainty range 401 Gg-1453 Gg, while OC emissions are 9224 Gg with uncertainty ranging between 5596 Gg and 14,736 Gg. Wildfires dominated and contributed about 83% of the total BC emissions: however, the effect on radiative forcing is mitigated in part by OC emissions. We also present an adjusted estimate of Arctic forcing from Russia's BC and OC emissions. In recent years, Russia has pursued policies to reduce flaring and limit particulate emissions from on-road transport, both of which appear to significantly contribute to the lower emissions and forcing values found in this study.

'Diamond Jenness': Before the Grind

NASA Technical Reports Server (NTRS)

2004-01-01

This microscopic imager mosaic of the rock called 'Diamond Jenness' was snapped on sol 177 before NASA's Mars Exploration Rover Opportunity ground into the surface with its rock abrasion tool, or 'Rat.'

Opportunity has bored nearly a dozen holes into the inner walls of 'Endurance Crater.' On sols 177 and 178 (July 23 and July 24, 2004), the rover worked double-duty on Diamond Jenness. Surface debris and the bumpy shape of the rock resulted in a shallow and irregular hole, only about 2 millimeters (0.08 inch) deep. The final depth was not enough to remove all the bumps and leave a neat hole with a smooth floor. This extremely shallow depression was then examined by the rover's alpha particle X-ray spectrometer. On Sol 178, Opportunity's 'robotic rodent' dined on Diamond Jenness once again, grinding almost an additional 5 millimeters (about 0.2 inch). The rover then applied its Moessbauer spectrometer to the deepened hole. This double dose of Diamond Jenness enabled the science team to examine the rock at varying layers. Results from those grindings are currently being analyzed.

The image mosaic is about 6 centimeters (2.4 inches) across.

'Diamond' in 3-D

NASA Technical Reports Server (NTRS)

2004-01-01

This 3-D, microscopic imager mosaic of a target area on a rock called 'Diamond Jenness' was taken after NASA's Mars Exploration Rover Opportunity ground into the surface with its rock abrasion tool for a second time.

Opportunity has bored nearly a dozen holes into the inner walls of 'Endurance Crater.' On sols 177 and 178 (July 23 and July 24, 2004), the rover worked double-duty on Diamond Jenness. Surface debris and the bumpy shape of the rock resulted in a shallow and irregular hole, only about 2 millimeters (0.08 inch) deep. The final depth was not enough to remove all the bumps and leave a neat hole with a smooth floor. This extremely shallow depression was then examined by the rover's alpha particle X-ray spectrometer.

On Sol 178, Opportunity's 'robotic rodent' dined on Diamond Jenness once again, grinding almost an additional 5 millimeters (about 0.2 inch). The rover then applied its Moessbauer spectrometer to the deepened hole. This double dose of Diamond Jenness enabled the science team to examine the rock at varying layers. Results from those grindings are currently being analyzed.

The image mosaic is about 6 centimeters (2.4 inches) across.

'Diamond Jenness': A Tough Grind

NASA Technical Reports Server (NTRS)

2004-01-01

This microscopic imager mosaic of the target area called 'Diamond Jenness' was taken after NASA's Mars Exploration Rover Opportunity ground into the surface with its rock abrasion tool for a second time.

Opportunity has bored nearly a dozen holes into the inner walls of 'Endurance Crater.' On sols 177 and 178 (July 23 and July 24, 2004), the rover worked double-duty on Diamond Jenness. Surface debris and the bumpy shape of the rock resulted in a shallow and irregular hole, only about 2 millimeters (0.08 inch) deep. The final depth was not enough to remove all the bumps and leave a neat hole with a smooth floor. This extremely shallow depression was then examined by the rover's alpha particle X-ray spectrometer.

On Sol 178, Opportunity's 'robotic rodent' dined on Diamond Jenness once again, grinding almost an additional 5 millimeters (about 0.2 inch). The rover then applied its Moessbauer spectrometer to the deepened hole. This double dose of Diamond Jenness enabled the science team to examine the rock at varying layers. Results from those grindings are currently being analyzed.

The image mosaic is about 6 centimeters (2.4 inches) across.

Spirit Begins Third Martian Year

NASA Technical Reports Server (NTRS)

2007-01-01

As it finished its second Martian year on Mars, NASA's Mars Exploration Rover Spirit was beginning to examine a group of angular rocks given informal names corresponding to peaks in the Colorado Rockies. A Martian year the amount of time it takes Mars to complete one orbit around the sun lasts for 687 Earth days. Spirit completed its second Martian year on the rover's 1,338th Martian day, or sol, corresponding to Oct. 8, 2007.

Two days later, on sol 1,340 (Oct. 10, 2007), Spirit used its front hazard-identification camera to capture this wide-angle view of its robotic arm extended to a rock informally named 'Humboldt Peak.' For the rocks at this site on the southern edge of the 'Home Plate' platform in the inner basin of the Columbia Hills inside Gusev Crater, the rover team decided to use names of Colorado peaks higher than 14,000 feet. The Colorado Rockies team of the National League is the connection to the baseball-theme nomenclature being used for features around Home Plate.

The tool facing Spirit on the turret at the end of the robotic arm is the Moessbauer spectrometer.

Fusing Image Data for Calculating Position of an Object

NASA Technical Reports Server (NTRS)

Huntsberger, Terrance; Cheng, Yang; Liebersbach, Robert; Trebi-Ollenu, Ashitey

2007-01-01

A computer program has been written for use in maintaining the calibration, with respect to the positions of imaged objects, of a stereoscopic pair of cameras on each of the Mars Explorer Rovers Spirit and Opportunity. The program identifies and locates a known object in the images. The object in question is part of a Moessbauer spectrometer located at the tip of a robot arm, the kinematics of which are known. In the program, the images are processed through a module that extracts edges, combines the edges into line segments, and then derives ellipse centroids from the line segments. The images are also processed by a feature-extraction algorithm that performs a wavelet analysis, then performs a pattern-recognition operation in the wavelet-coefficient space to determine matches to a texture feature measure derived from the horizontal, vertical, and diagonal coefficients. The centroids from the ellipse finder and the wavelet feature matcher are then fused to determine co-location. In the event that a match is found, the centroid (or centroids if multiple matches are present) is reported. If no match is found, the process reports the results of the analyses for further examination by human experts.

'Diamond Jenness': Before the Grind

NASA Image and Video Library

2004-08-03

This microscopic imager mosaic of the rock called "Diamond Jenness" was snapped on sol 177 before NASA's Mars Exploration Rover Opportunity ground into the surface with its rock abrasion tool, or "Rat." Opportunity has bored nearly a dozen holes into the inner walls of "Endurance Crater." On sols 177 and 178 (July 23 and July 24, 2004), the rover worked double-duty on Diamond Jenness. Surface debris and the bumpy shape of the rock resulted in a shallow and irregular hole, only about 2 millimeters (0.08 inch) deep. The final depth was not enough to remove all the bumps and leave a neat hole with a smooth floor. This extremely shallow depression was then examined by the rover's alpha particle X-ray spectrometer. On Sol 178, Opportunity's "robotic rodent" dined on Diamond Jenness once again, grinding almost an additional 5 millimeters (about 0.2 inch). The rover then applied its Moessbauer spectrometer to the deepened hole. This double dose of Diamond Jenness enabled the science team to examine the rock at varying layers. Results from those grindings are currently being analyzed. The image mosaic is about 6 centimeters (2.4 inches) across. http://photojournal.jpl.nasa.gov/catalog/PIA06748

Odor and odorous chemical emissions from animal buildings: Part 2. Odor emissions

USDA-ARS?s Scientific Manuscript database

This study was an add-on project to the National Air Emissions Monitoring Study (NAEMS) and focused on comprehensive measurement of odor emissions considering variations in seasons, animal types and olfactometry laboratories. Odor emissions from four of 14 NEAMS sites with nine barns/rooms (two dair...

Black carbon emissions in Russia: A critical review

DOE PAGES

Evans, Meredydd; Kholod, Nazar; Kuklinski, Teresa; ...

2017-05-18

Here, this study presents a comprehensive review of estimated black carbon (BC) emissions in Russia from a range of studies. Russia has an important role regarding BC emissions given the extent of its territory above the Arctic Circle, where BC emissions have a particularly pronounced effect on the climate. We assess underlying methodologies and data sources for each major emissions source based on their level of detail, accuracy and extent to which they represent current conditions. We then present reference values for each major emissions source. In the case of flaring, the study presents new estimates drawing on data onmore » Russia's associated petroleum gas and the most recent satellite data on flaring. We also present estimates of organic carbon (OC) for each source, either based on the reference studies or from our own calculations. In addition, the study provides uncertainty estimates for each source. Total BC emissions are estimated at 688 Gg in 2014, with an uncertainty range 401 Gg-1453 Gg, while OC emissions are 9224 Gg with uncertainty ranging between 5596 Gg and 14,736 Gg. Wildfires dominated and contributed about 83% of the total BC emissions: however, the effect on radiative forcing is mitigated in part by OC emissions. We also present an adjusted estimate of Arctic forcing from Russia's BC and OC emissions. In recent years, Russia has pursued policies to reduce flaring and limit particulate emissions from on-road transport, both of which appear to significantly contribute to the lower emissions and forcing values found in this study.« less

Black carbon emissions in Russia: A critical review

DOE Office of Scientific and Technical Information (OSTI.GOV)

Evans, Meredydd; Kholod, Nazar; Kuklinski, Teresa

Here, this study presents a comprehensive review of estimated black carbon (BC) emissions in Russia from a range of studies. Russia has an important role regarding BC emissions given the extent of its territory above the Arctic Circle, where BC emissions have a particularly pronounced effect on the climate. We assess underlying methodologies and data sources for each major emissions source based on their level of detail, accuracy and extent to which they represent current conditions. We then present reference values for each major emissions source. In the case of flaring, the study presents new estimates drawing on data onmore » Russia's associated petroleum gas and the most recent satellite data on flaring. We also present estimates of organic carbon (OC) for each source, either based on the reference studies or from our own calculations. In addition, the study provides uncertainty estimates for each source. Total BC emissions are estimated at 688 Gg in 2014, with an uncertainty range 401 Gg-1453 Gg, while OC emissions are 9224 Gg with uncertainty ranging between 5596 Gg and 14,736 Gg. Wildfires dominated and contributed about 83% of the total BC emissions: however, the effect on radiative forcing is mitigated in part by OC emissions. We also present an adjusted estimate of Arctic forcing from Russia's BC and OC emissions. In recent years, Russia has pursued policies to reduce flaring and limit particulate emissions from on-road transport, both of which appear to significantly contribute to the lower emissions and forcing values found in this study.« less

Black carbon emissions in Russia: A critical review

DOE Office of Scientific and Technical Information (OSTI.GOV)

Evans, Meredydd; Kholod, Nazar; Kuklinski, Teresa

Russia has a particularly important role regarding black carbon (BC) emissions given the extent of its territory above the Arctic Circle, where BC emissions have a particularly pronounced effect on the climate. This study presents a comprehensive review of BC estimates from a range of studies. We assess underlying methodologies and data sources for each major emissions source based on their level of detail, accuracy and extent to which they represent current conditions. We then present reference values for each major emissions source. In the case of flaring, the study presents new estimates drawing on data on Russian associated petroleummore » gas and the most recent satellite data on flaring. We also present estimates of organic carbon (OC) for each source, either based on the reference studies or from our own calculations. In addition, the study provides uncertainty estimates for each source. Total BC emissions are estimated at 689 Gg in 2014, with an uncertainty range between (407-1,416), while OC emissions are 9,228 Gg (with uncertainty between 5,595 and 14,728). Wildfires dominated and contributed about 83% of the total BC emissions, however the effect on radiative forcing is mitigated by OC emissions. We also present an adjusted estimate of Arctic forcing from Russian OC and BC emissions. In recent years, Russia has pursued policies to reduce flaring and limit particulate emissions from on-road transport, both of which appear to significantly contribute to the lower emissions and forcing values found in this study.« less

Estimation of vehicular emissions using dynamic emission factors: A case study of Delhi, India

NASA Astrophysics Data System (ADS)

Mishra, Dhirendra; Goyal, P.

2014-12-01

The estimation of vehicular emissions depends mainly on the values of emission factors, which are used for the development of a comprehensive emission inventory of vehicles. In this study the variations of emission factors as well as the emission rates have been studied in Delhi. The implementation of compressed natural gas (CNG), in the diesel and petrol, public vehicles in the year 2001 has changed the complete air quality scenario of Delhi. The dynamic emission factors of criteria pollutants viz. carbon monoxide (CO), nitrogen oxide (NOx) and particulate matter (PM10) for all types of vehicles have been developed after, which are based on the several factors such as regulated emission limits, number of vehicle deterioration, vehicle increment, vehicle age etc. These emission factors are found to be decreased continuously throughout the study years 2003-2012. The International Vehicle Emissions (IVE) model is used to estimate the emissions of criteria pollutants by utilizing a dataset available from field observations at different traffic intersections in Delhi. Thus the vehicular emissions, based on dynamic emission factors have been estimated for the years 2003-2012, which are found to be comparable with the monitored concentrations at different locations in Delhi. It is noticed that the total emissions of CO, NOx, and PM10 are increased by 45.63%, 68.88% and 17.92%, respectively up to the year 2012 and the emissions of NOx and PM10 are grown continuously with an annual average growth rate of 5.4% and 1.7% respectively.

The role of FDG-PET in detecting rejection after liver transplantation.

PubMed

Watson, Ashley M; Bhutiani, Neal; Philips, Prejesh; Davis, Eric G; Eng, Mary; Cannon, Robert M; Jones, Christopher M

2018-05-15

The activation and increased metabolic activity of T cells in acute cellular rejection could allow fluoro-2-deoxyglucose positron emission tomography to be utilized for detection of acute cellular rejection. The objective of this study was to evaluate the effectiveness of fluoro-2-deoxyglucose positron emission tomography in detecting acute cellular rejection in the clinical setting. Fluoro-2-deoxyglucose positron emission tomography studies were performed on 88 orthotopic liver transplant patients at 7 and 17 days postoperatively (first positron emission tomography and second positron emission tomography, respectively). Additional studies were performed if patients had suspicion of rejection and at resolution of rejection (third positron emission tomography and fourth positron emission tomography, respectively). A circular region of interest was placed over the liver for semiquantitative evaluation of fluoro-2-deoxyglucose positron emission tomography images by means of standard uptake values. Eighteen of 88 patients in our study (20.5%) had histologically proven acute cellular rejection during a 16 ± 11 day follow-up. There was no significant difference between the standard uptake values of first positron emission tomography among non-rejecters versus rejecters (2.05 ±0.46 non-rejecters versus 1.82 ± 0.40 rejecters, P = .127). Within the rejection cohort, the standard uptake values from the third positron emission tomography (rejection) were higher compared to the first positron emission tomography (baseline) (2.41 ± 0.48 third positron emission tomography versus 1.82 ± 0.41 first positron emission tomography, P < .001). Increased signal on fluoro-2-deoxyglucose positron emission tomography over baseline is associated with acute cellular rejection in liver transplant recipients. Additional prospective validation studies are essential to define the role of fluoro-2-deoxyglucose positron emission tomography scan as an early marker for acute cellular rejection. Copyright © 2018 Elsevier Inc. All rights reserved.

Comparison of emission factors for road traffic from a tunnel study (Gubrist tunnel, Switzerland) and from emission modeling

NASA Astrophysics Data System (ADS)

John, Christian; Friedrich, Rainer; Staehelin, Johannes; Schläpfer, Kurt; Stahel, Werner A.

The emission factors of NO x, VOC and CO of a road tunnel study performed in September 1993 in the Gubrist tunnel, close to Zürich (Switzerland) are compared with results of emission calculations based on recent results of dynamometric test measurements. The emission calculations are carried out with a traffic emission model taking into account the detailed composition of the vehicle fleet in the tunnel, the average speed and the gradient of the road and the special aerodynamics in a tunnel. With the exception of NO x emission factors for heavy duty vehicles no evidence for a discrepancy between the results of the tunnel study and the emission modeling was found. The measured emission factors of individual hydrocarbons of light duty vehicles were in good agreement with the expectations for most components.

Odor and odorous chemical emissions from animal buildings: Part 2 - odor emissions

USDA-ARS?s Scientific Manuscript database

This study was an add-on project to the National Air Emissions Monitoring Study (NAEMS) and focused on comprehensive measurement of odor emissions. Odor emissions from two animal species (dairy and swine) from four sites with nine barns/rooms (two dairy barns in Wisconsin, two dairy barns and two sw...

Characterization of outdoor air particles as source of impurities in supply air

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pasanen, P.; Kalliokoski, P.; Tuomainen, A.

1997-12-31

Odor emission of supply air filters has proved to be a major source of stuffy odor of supply air. In this study, the odor emission characteristics of outdoor air particles and odor emissions of coarse prefilters and fine filters were studied. The outdoor air samples were collected by the aid of high volume impactor. Odor emissions of the size fractions, < 2.1 {micro}m , 2.1--10 {micro}m and >10 {micro}m were studied separately in laboratory with a trained olf panel: The odor emissions of the ventilation filters in real use were evaluated five times during the 14 month study period. Aftermore » the field evaluation the emissions of carbonyl compounds and other volatile organic compounds. The odor emissions of outdoor air particles were the highest during the heating season and lowest in the summer. The particles in the coarsest fraction had the most abundant emissions (1,200 olf/g) while the emissions from fine particles were lowest (100 olf/g). The odor emissions evaluated from the coarse and fine ventilation filters supported the finding that particles collected on coarse prefilter had the most abundant odor emission.« less

The impact of local government investment on the carbon emissions reduction effect: An empirical analysis of panel data from 30 provinces and municipalities in China.

PubMed

He, Lingyun; Yin, Fang; Zhong, Zhangqi; Ding, Zhihua

2017-01-01

Among studies of the factors that influence carbon emissions and related regulations, economic aggregates, industrial structures, energy structures, population levels, and energy prices have been extensively explored, whereas studies from the perspective of fiscal leverage, particularly of local government investment (LGI), are rare. Of the limited number of studies on the effect of LGI on carbon emissions, most focus on its direct effect. Few studies consider regulatory effects, and there is a lack of emphasis on local areas. Using a cointegration test, a panel data model and clustering analysis based on Chinese data between 2000 and 2013, this study measures the direct role of LGI in carbon dioxide (CO2) emissions reduction. First, overall, within the sample time period, a 1% increase in LGI inhibits carbon emissions by 0.8906% and 0.5851% through its influence on the industrial structure and energy efficiency, respectively, with the industrial structure path playing a greater role than the efficiency path. Second, carbon emissions to some extent exhibit inertia. The previous year's carbon emissions impact the following year's carbon emissions by 0.5375%. Thus, if a reduction in carbon emissions in the previous year has a positive effect, then the carbon emissions reduction effect generated by LGI in the following year will be magnified. Third, LGI can effectively reduce carbon emissions, but there are significant regional differences in its impact. For example, in some provinces, such as Sichuan and Anhui, economic growth has not been decoupled from carbon emissions. Fourth, the carbon emissions reduction effect in the 30 provinces and municipalities sampled in this study can be classified into five categories-strong, relatively strong, medium, relatively weak and weak-based on the degree of local governments' regulation of carbon emissions. The carbon emissions reduction effect of LGI is significant in the western and central regions of China but not in the eastern and northeast regions. This study helps overcome the limitations of previous studies on the regulatory effects of LGI on carbon emissions, and the constructed model may more closely reflect actual economic conditions. Moreover, the current study can benefit countries similar to China that aim to objectively identify the impacts of their LGI on carbon emissions, and such countries can use it as a reference in the formulation of investment policies based on their economic and industrial characteristics.

The impact of local government investment on the carbon emissions reduction effect: An empirical analysis of panel data from 30 provinces and municipalities in China

PubMed Central

He, Lingyun; Yin, Fang; Zhong, Zhangqi; Ding, Zhihua

2017-01-01

Among studies of the factors that influence carbon emissions and related regulations, economic aggregates, industrial structures, energy structures, population levels, and energy prices have been extensively explored, whereas studies from the perspective of fiscal leverage, particularly of local government investment (LGI), are rare. Of the limited number of studies on the effect of LGI on carbon emissions, most focus on its direct effect. Few studies consider regulatory effects, and there is a lack of emphasis on local areas. Using a cointegration test, a panel data model and clustering analysis based on Chinese data between 2000 and 2013, this study measures the direct role of LGI in carbon dioxide (CO2) emissions reduction. First, overall, within the sample time period, a 1% increase in LGI inhibits carbon emissions by 0.8906% and 0.5851% through its influence on the industrial structure and energy efficiency, respectively, with the industrial structure path playing a greater role than the efficiency path. Second, carbon emissions to some extent exhibit inertia. The previous year’s carbon emissions impact the following year’s carbon emissions by 0.5375%. Thus, if a reduction in carbon emissions in the previous year has a positive effect, then the carbon emissions reduction effect generated by LGI in the following year will be magnified. Third, LGI can effectively reduce carbon emissions, but there are significant regional differences in its impact. For example, in some provinces, such as Sichuan and Anhui, economic growth has not been decoupled from carbon emissions. Fourth, the carbon emissions reduction effect in the 30 provinces and municipalities sampled in this study can be classified into five categories—strong, relatively strong, medium, relatively weak and weak—based on the degree of local governments’ regulation of carbon emissions. The carbon emissions reduction effect of LGI is significant in the western and central regions of China but not in the eastern and northeast regions. This study helps overcome the limitations of previous studies on the regulatory effects of LGI on carbon emissions, and the constructed model may more closely reflect actual economic conditions. Moreover, the current study can benefit countries similar to China that aim to objectively identify the impacts of their LGI on carbon emissions, and such countries can use it as a reference in the formulation of investment policies based on their economic and industrial characteristics. PMID:28727783

The relationship between gasoline composition and vehicle hydrocarbon emissions: a review of current studies and future research needs.

PubMed Central

Schuetzle, D; Siegl, W O; Jensen, T E; Dearth, M A; Kaiser, E W; Gorse, R; Kreucher, W; Kulik, E

1994-01-01

The purpose of this paper is to review current studies concerning the relationship of fuel composition to vehicle engine-out and tail-pipe emissions and to outline future research needed in this area. A number of recent combustion experiments and vehicle studies demonstrated that reformulated gasoline can reduce vehicle engine-out, tail-pipe, running-loss, and evaporative emissions. Some of these studies were extended to understand the fundamental relationships between fuel composition and emissions. To further establish these relationships, it was necessary to develop advanced analytical methods for the qualitative and quantitative analysis of hydrocarbons in fuels and vehicle emissions. The development of real-time techniques such as Fourier transform infrared spectroscopy, laser diode spectroscopy, and atmospheric pressure ionization mass spectrometry were useful in studying the transient behavior of exhaust emissions under various engine operating conditions. Laboratory studies using specific fuels and fuel blends were carried out using pulse flame combustors, single- and multicylinder engines, and vehicle fleets. Chemometric statistical methods were used to analyze the large volumes of emissions data generated from these studies. Models were developed that were able to accurately predict tail-pipe emissions from fuel chemical and physical compositional data. Some of the primary fuel precursors for benzene, 1,3-butadiene, formaldehyde, acetaldehyde and C2-C4 alkene emissions are described. These studies demonstrated that there is a strong relationship between gasoline composition and tail-pipe emissions. PMID:7529705

The relationship between gasoline composition and vehicle hydrocarbon emissions: a review of current studies and future research needs.

PubMed

Schuetzle, D; Siegl, W O; Jensen, T E; Dearth, M A; Kaiser, E W; Gorse, R; Kreucher, W; Kulik, E

1994-10-01

The purpose of this paper is to review current studies concerning the relationship of fuel composition to vehicle engine-out and tail-pipe emissions and to outline future research needed in this area. A number of recent combustion experiments and vehicle studies demonstrated that reformulated gasoline can reduce vehicle engine-out, tail-pipe, running-loss, and evaporative emissions. Some of these studies were extended to understand the fundamental relationships between fuel composition and emissions. To further establish these relationships, it was necessary to develop advanced analytical methods for the qualitative and quantitative analysis of hydrocarbons in fuels and vehicle emissions. The development of real-time techniques such as Fourier transform infrared spectroscopy, laser diode spectroscopy, and atmospheric pressure ionization mass spectrometry were useful in studying the transient behavior of exhaust emissions under various engine operating conditions. Laboratory studies using specific fuels and fuel blends were carried out using pulse flame combustors, single- and multicylinder engines, and vehicle fleets. Chemometric statistical methods were used to analyze the large volumes of emissions data generated from these studies. Models were developed that were able to accurately predict tail-pipe emissions from fuel chemical and physical compositional data. Some of the primary fuel precursors for benzene, 1,3-butadiene, formaldehyde, acetaldehyde and C2-C4 alkene emissions are described. These studies demonstrated that there is a strong relationship between gasoline composition and tail-pipe emissions.

Unusual ordering in c-NpPd3

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gofryk, Krzysztof

2010-01-01

NpPd{sub 3} exhibits two crystal structures. At room temperature, the equilibrium structure is the dhcp TiNi{sub 3}-type, but rapid cooling from melt produces the cubic AuCu{sub 3}-type structure. In both cases, the Np-Np distance is 4.1 {angstrom}, so that the Np ions are expected to be localized. Both phases of NpPd{sub 3} were first studied at the ANL in the early 1970s. Nellis et al measured the magnetic susceptibility and the electrical resistivity of cubic NpPd{sub 3}, and found evidence of magnetic ordering setting in below T{sub N} = 54 K. The magnetic order in this phase was confirmed bymore » Moessbauer and neutron studies. The neutron data revealed several magnetic Bragg peaks with an ordering wave-vector of (1/2,1/2, 1/2). In contrast, no evidence for any long-range magnetic ordering was found for dhcp NpPd{sub 3}, despite the presence of an anomaly at 30 K in the bulk magnetic data. Our recent measurements of the magnetic (magnetization, susceptibility), thermal (heat capacity) and transport (electrical resistivity, magnetoresistivity, thermopower and Hall effect) properties of cubic NpPd{sub 3} indicated highly unusual nature of the magnetic ordering. At T{sub N}, the specific heat exhibits an extremely large peak [as large as 1000 J/(mol K)] and the magnetic susceptibility shows a clear jump. The transport properties of c-NpPd{sub 3} indicate a dramatic Fermi-surface reconstruction at T{sub N}, which shows up as pronounced anomalies at this temperature in the electrical resistivity, the magnetoresistivity, the Seebeck coefficient and the Hall coefficient.« less

Comparing Top-down and Bottom-up Estimates of Methane Emissions across Multiple U.S. Basins Provides Insights into National Oil and Gas Emissions and Mitigation Strategies

NASA Astrophysics Data System (ADS)

Hamburg, S.; Alvarez, R.; Lyon, D. R.; Zavala-Araiza, D.

2016-12-01

Several recent studies quantified regional methane emissions in U.S. oil and gas (O&G) basins using top-down approaches such as airborne mass balance measurements. These studies apportioned total methane emissions to O&G based on hydrocarbon ratios or subtracting bottom-up estimates of other sources. In most studies, top-down estimates of O&G methane emissions exceeded bottom-up emission inventories. An exception is the Barnett Shale Coordinated Campaign, which found agreement between aircraft mass balance estimates and a custom emission inventory. Reconciliation of Barnett Shale O&G emissions depended on two key features: 1) matching the spatial domains of top-down and bottom-up estimates, and 2) accounting for fat-tail sources in site-level emission factors. We construct spatially explicit custom emission inventories for domains with top-down O&G emission estimates in eight major U.S. oil and gas production basins using a variety of data sources including a spatially-allocated U.S. EPA Greenhouse Gas Inventory, the EPA Greenhouse Gas Reporting Program, state emission inventories, and recently published measurement studies. A comparison of top-down and our bottom-up estimates of O&G emissions constrains the gap between these approaches and elucidates regional variability in production-normalized loss rates. A comparison of component-level and site-level emission estimates of production sites in the Barnett Shale region - where comprehensive activity data and emissions estimates are available - indicates that abnormal process conditions contribute about 20% of regional O&G emissions. Combining these two analyses provides insights into the relative importance of different equipment, processes, and malfunctions to emissions in each basin. These data allow us to estimate the U.S. O&G supply chain loss rate, recommend mitigation strategies to reduce emissions from existing infrastructure, and discuss how a similar approach can be applied internationally.

The effects of deterioration and technological levels on pollutant emission factors for gasoline light-duty trucks.

PubMed

Zhang, Qingyu; Fan, Juwang; Yang, Weidong; Chen, Bixin; Zhang, Lijuan; Liu, Jiaoyu; Wang, Jingling; Zhou, Chunyao; Chen, Xuan

2017-07-01

Vehicle deterioration and technological change influence emission factors (EFs). In this study, the impacts of vehicle deterioration and emission standards on EFs of regulated pollutants (carbon monoxide [CO], hydrocarbon [HC], and nitrogen oxides [NO x ]) for gasoline light-duty trucks (LDTs) were investigated according to the inspection and maintenance (I/M) data using a chassis dynamometer method. Pollutant EFs for LDTs markedly varied with accumulated mileages and emission standards, and the trends of EFs are associated with accumulated mileages. In addition, the study also found that in most cases, the median EFs of CO, HC, and NO x are higher than those of basic EFs in the International Vehicle Emissions (IVE) model; therefore, the present study provides correction factors for the IVE model relative to the corresponding emission standards and mileages. Currently, vehicle emissions are great contributors to air pollution in cities, especially in developing countries. Emission factors play a key role in creating emission inventory and estimating emissions. Deterioration represented by vehicle age and accumulated mileage and changes of emission standards markedly influence emission factors. In addition, the results provide collection factors for implication in the IVE model in the region levels.

Volatile Organic Compound Emissions by Agricultural Crops

NASA Astrophysics Data System (ADS)

Ormeno, E.; Farres, S.; Gentner, D.; Park, J.; McKay, M.; Karlik, J.; Goldstein, A.

2008-12-01

Biogenic Volatile Organic Compounds (BVOCs) participate in ozone and aerosol formation, and comprise a substantial fraction of reactive VOC emission inventories. In the agriculturally intensive Central Valley of California, emissions from crops may substantially influence regional air quality, but emission potentials have not been extensively studied with advanced instrumentation for many important crops. Because crop emissions may vary according to the species, and California emission inventories are constructed via a bottom-up approach, a better knowledge of the emission rate at the species-specific level is critical for reducing uncertainties in emission inventories and evaluating emission model performance. In the present study we identified and quantified the BVOCs released by dominant agricultural crops in California. A screening study to investigate both volatile and semivolatile BVOC fractions (oxygenated VOCs, isoprene, monoterepenes, sesquiterpenes, etc.) was performed for 25 crop species (at least 3 replicates plants each), including branch enclosures of woody species (e.g. peach, mandarin, grape, pistachio) and whole plant enclosures for herbaceous species (e.g. onion, alfalfa, carrot), through a dynamic cuvette system with detection by PTRMS, in-situ GCMS/FID, and collection on carbon-based adsorbents followed by extraction and GCMS analysis. Emission data obtained in this study will allow inclusion of these crops in BVOC emission inventories and air quality simulations.

The challenges of reducing greenhouse gas emissions and air pollution through energy sources: evidence from a panel of developed countries.

PubMed

Akhmat, Ghulam; Zaman, Khalid; Shukui, Tan; Sajjad, Faiza; Khan, Muhammad Azhar; Khan, Muhammad Zahir

2014-06-01

The objective of the study is to investigate the long-run relationship between climatic factors (i.e., greenhouse gas emissions, agricultural methane emissions, and industrial nitrous oxide emission), air pollution (i.e., carbon dioxide emissions), and energy sources (i.e., nuclear energy; oil, gas, and coal energy; and fossil fuel energy) in the panel of 35 developed countries (including EU-15, new EU member states, G-7, and other countries) over a period of 1975-2012. In order to achieve this objective, the present study uses sophisticated panel econometric techniques including panel cointegration, panel fully modified OLS (FMOLS), and dynamic OLS (DOLS). The results show that there is a long-run relationship between the variables. Nuclear energy reduces greenhouse gases and carbon emissions; however, the other emissions, i.e., agricultural methane emissions and industrial nitrous oxide, are still to increase during the study period. Electricity production from oil, gas, and coal sources increases the greenhouse gases and carbon emissions; however, the intensity to increase emissions is far less than the intensity to increase emissions through fossil fuel. Policies that reduce emissions of greenhouse gases can simultaneously alter emissions of conventional pollutants that have deleterious effects on human health and the environment.

Shipping emissions and their impacts on air quality in China.

PubMed

Zhang, Yan; Yang, Xin; Brown, Richard; Yang, Liping; Morawska, Lidia; Ristovski, Zoran; Fu, Qingyan; Huang, Cheng

2017-03-01

China has >400 ports, is home to 7 of 10 biggest ports in the world and its waterway infrastructure construction has been accelerating over the past years. But the increasing number of ports and ships means increasing emissions, and in turn, increasing impact on local and regional air pollution. This paper presents an overview of the broad field of ship emissions in China and their atmospheric impacts, including topics of ship engine emissions and control, ship emission factors and their measurements, developing of ship emission inventories, shipping and port emissions of the main shipping areas in China, and quantitative contribution of shipping emissions to the local and regional air pollution. There have been an increasing number of studies published on all the above aspects, yet, this review identified some critical research gaps, filling of which is necessary for better control of ship emissions, and for lowering their impacts. In particular, there are very few studies on inland ports and river ships, and there are few national scale ship emission inventories available for China. While advanced method to estimate ship emission based on ship AIS activities makes it now possible to develop high spatial- and temporal-resolution emission inventories, the ship emission factors used in Chinese studies have been based mainly on foreign measurements. Further, the contribution of ship emissions to air pollution in coastal cities, the dispersion of pollution plumes emitted by ships, or the chemical evolution process along the transmission path, have so far not been systematically studied in China. Copyright © 2016 Elsevier B.V. All rights reserved.

Methane Emissions from the Natural Gas Transmission and Storage System in the United States.

PubMed

Zimmerle, Daniel J; Williams, Laurie L; Vaughn, Timothy L; Quinn, Casey; Subramanian, R; Duggan, Gerald P; Willson, Bryan; Opsomer, Jean D; Marchese, Anthony J; Martinez, David M; Robinson, Allen L

2015-08-04

The recent growth in production and utilization of natural gas offers potential climate benefits, but those benefits depend on lifecycle emissions of methane, the primary component of natural gas and a potent greenhouse gas. This study estimates methane emissions from the transmission and storage (T&S) sector of the United States natural gas industry using new data collected during 2012, including 2,292 onsite measurements, additional emissions data from 677 facilities and activity data from 922 facilities. The largest emission sources were fugitive emissions from certain compressor-related equipment and "super-emitter" facilities. We estimate total methane emissions from the T&S sector at 1,503 [1,220 to 1,950] Gg/yr (95% confidence interval) compared to the 2012 Environmental Protection Agency's Greenhouse Gas Inventory (GHGI) estimate of 2,071 [1,680 to 2,690] Gg/yr. While the overlap in confidence intervals indicates that the difference is not statistically significant, this is the result of several significant, but offsetting, factors. Factors which reduce the study estimate include a lower estimated facility count, a shift away from engines toward lower-emitting turbine and electric compressor drivers, and reductions in the usage of gas-driven pneumatic devices. Factors that increase the study estimate relative to the GHGI include updated emission rates in certain emission categories and explicit treatment of skewed emissions at both component and facility levels. For T&S stations that are required to report to the EPA's Greenhouse Gas Reporting Program (GHGRP), this study estimates total emissions to be 260% [215% to 330%] of the reportable emissions for these stations, primarily due to the inclusion of emission sources that are not reported under the GHGRP rules, updated emission factors, and super-emitter emissions.

Greenhouse Gas and Ammonia Emissions from Different Stages of Liquid Manure Management Chains: Abatement Options and Emission Interactions.

PubMed

Mohankumar Sajeev, Erangu Purath; Winiwarter, Wilfried; Amon, Barbara

2018-01-01

Farm livestock manure is an important source of ammonia and greenhouse gases. Concerns over the environmental impact of emissions from manure management have resulted in research efforts focusing on emission abatement. However, questions regarding the successful abatement of manure-related emissions remain. This study uses a meta-analytical approach comprising 89 peer-reviewed studies to quantify emission reduction potentials of abatement options for liquid manure management chains from cattle and pigs. Analyses of emission reductions highlight the importance of accounting for interactions between emissions. Only three out of the eight abatement options considered (frequent removal of manure, anaerobic digesters, and manure acidification) reduced ammonia (3-60%), nitrous oxide (21-55%), and methane (29-74%) emissions simultaneously, whereas in all other cases, tradeoffs were identified. The results demonstrate that a shift from single-stage emission abatement options towards a whole-chain perspective is vital in reducing overall emissions along the manure management chain. The study also identifies some key elements like proper clustering, reporting of influencing factors, and explicitly describing assumptions associated with abatement options that can reduce variability in emission reduction estimates. Prioritization of abatement options according to their functioning can help to determine low-risk emission reduction options, specifically options that alter manure characteristics (e.g., reduced protein diets, anaerobic digestion, or slurry acidification). These insights supported by comprehensive emission measurement studies can help improve the effectiveness of emission abatement and harmonize strategies aimed at reducing air pollution and climate change simultaneously. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

A modeling study of direct and indirect N2O emissions from a representative catchment in the U. S. Corn Belt

USDA-ARS?s Scientific Manuscript database

Indirect nitrous oxide (N2O) emissions from drainage ditches and headwater streams are poorly constrained. To date, few studies have monitored stream N2O emissions and to our knowledge, no modeling studies have been conducted to simulate stream N2O emissions. In this study, we developed direct and i...

Real-World Vehicle Emissions: A Summary of the Sixth Coordinating Research Council On-Road Vehicle Emissions Workshop.

PubMed

Cadle, Steven H; Gorse, Robert A; Belian, Timothy C; Lawson, Douglas R

1997-03-01

The Coordinating Research Council (CRC) has conducted a series of workshops on real-world vehicle emissions. This article summarizes findings from the most recent research regarding on-road emissions from mobile sources, presented at the CRC workshop held in March 1996. Among the topics discussed were efforts to improve and update emission models, results from field studies designed to understand the contribution of mobile sources to emission inventories, results from gas-and particle-phase emissions studies from in-use motor vehicles, and areas of future research. The Sixth Coordinating Research Council (CRC) On-Road Vehicle Emissions Workshop was held March 18-20, 1996, in San Diego, CA. More than 160 representatives from academia, industry, government, and consulting firms in the United States, Canada, and Europe participated in the three-day meeting. The objective of the Workshop was to present the most recent information from research programs on: mobile source contributions to the emission inventory emission factor models and activity data model comparison and development emission reduction programs new developments in remote sensing studies of on-road vehicle exhaust and non-tailpipe emissions off-cycle Federal Test Procedure (FTP) studies and revisions to the FTP particle emissions from the light- and heavy-duty fleets future research needs Nine sessions were devoted to vehicle emissions models, improvements to the emission inventory, on-road and tunnel studies, off-cycle emissions, non-tailpipe and diesel emissions, emission reduction programs, and remote sensing. Overall workshop coordination was provided by Timothy Belian and the CRC staff, with Steven Cadle and Robert Gorse serving as cochairmen. Individual session chairmen were Brent Bailey (National Renewable Energy Laboratory), Mark Carlock (California Air Resources Board), Harold Haskew (General Motors), Kenneth Knapp and Philip Lorang (U.S. Environmental Protection Agency), Douglas Lawson (Colorado State University), Alan Lloyd (Desert Research Institute), Robert Slott (Shell Oil), and Timothy Truex (University of California, Riverside). In addition, during the Workshop, Lesha Hrynchuk of the California Air Resources Board (CARB) presented a hands-on demonstration using the Internet to obtain motor vehicle emissions information from groups throughout the world. The complete Workshop proceedings are available from the Coordinating Research Council, 219 Perimeter Center Parkway, Atlanta, GA 30346; phone: (770) 396-3400; fax: (770) 396-3404. The following summarizes each session and includes a short synopsis of all the papers that were presented.

Physical and chemical characterization of residual oil-fired power plant emissions

EPA Science Inventory

Although the toxicity of oil combustion emissions is a significant public health concern, few studies characterize the emissions from plant-scale utility boilers firing residual oil. This study remedies that deficiency by sampling and monitoring stack emissions from a 432 Giga Jo...

CO2 Emissions Embodied in Interprovincial Electricity Transmissions in China.

PubMed

Qu, Shen; Liang, Sai; Xu, Ming

2017-09-19

Existing studies on the evaluation of CO 2 emissions due to electricity consumption in China are inaccurate and incomplete. This study uses a network approach to calculate CO 2 emissions of purchased electricity in Chinese provinces. The CO 2 emission factors of purchased electricity range from 265 g/kWh in Sichuan to 947 g/kWh in Inner Mongolia. We find that emission factors of purchased electricity in many provinces are quite different from the emission factors of electricity generation. This indicates the importance of the network approach in accurately reflecting embodied emissions. We also observe substantial variations of emissions factors of purchased electricity within subnational grids: the provincial emission factors deviate from the corresponding subnational-grid averages from -58% to 44%. This implies that using subnational-grid averages as required by Chinese government agencies can be quite inaccurate for reporting indirect CO 2 emissions of enterprises' purchased electricity. The network approach can improve the accuracy of the quantification of embodied emissions in purchased electricity and emission flows embodied in electricity transmission.

Analysis and Modeling of Jovian Radio Emissions Observed by Galileo

NASA Technical Reports Server (NTRS)

Menietti, J. D.

2003-01-01

Our studies of Jovian radio emission have resulted in the publication of five papers in refereed journals, with three additional papers in progress. The topics of these papers include the study of narrow-band kilometric radio emission; the apparent control of radio emission by Callisto; quasi-periodic radio emission; hectometric attenuation lanes and their relationship to Io volcanic activity; and modeling of HOM attenuation lanes using ray tracing. A further study of the control of radio emission by Jovian satellites is currently in progress. Abstracts of each of these papers are contained in the Appendix. A list of the publication titles are also included.

Sectoral roles in greenhouse gas emissions and policy implications for energy utilization and carbon emissions trading: a case study of Beijing, China.

PubMed

Ge, Jianping; Lei, Yalin; Xu, Qun; Wang, Xibo

2016-01-01

In this study, a decomposition and emissions matrix is developed to identify the roles (giver or taker) played by the sectors in the greenhouse gas emissions for the economy of Beijing in China. Our results indicate that services were the most important emitter if we consider the total (direct and indirect) emissions. In addition to Construction, Scientific studies and technical services and Finance sectors of services were the largest takers. They have a large role in boosting greenhouse gas emissions throughout the economy of Beijing. As the basis and supporter of production activities, the electricity production and the transportation sectors were the greatest givers. More emphasis should be placed on using clean energy and carbon capture and storage technologies to reduce emissions within these sectors. Based on the roles played by these sectors in greenhouse gas emissions, some policy implications were proposed for energy utilization and carbon emissions trading.

Variability and Quasi-Decadal Changes in the Methane Budget over the Period 2000-2012

NASA Technical Reports Server (NTRS)

Saunois, Marielle; Bousquet, Philippe; Poulter, Ben; Peregon, Anna; Ciais, Philippe; Canadell, Josep G.; Dlugokencky, Edward J.; Etiope, Giuseppe; Bastviken, David; Houweling, Sander;

Variability and quasi-decadal changes in the methane budget over the period 2000-2012

NASA Astrophysics Data System (ADS)

Saunois, Marielle; Bousquet, Philippe; Poulter, Ben; Peregon, Anna; Ciais, Philippe; Canadell, Josep G.; Dlugokencky, Edward J.; Etiope, Giuseppe; Bastviken, David; Houweling, Sander; Janssens-Maenhout, Greet; Tubiello, Francesco N.; Castaldi, Simona; Jackson, Robert B.; Alexe, Mihai; Arora, Vivek K.; Beerling, David J.; Bergamaschi, Peter; Blake, Donald R.; Brailsford, Gordon; Bruhwiler, Lori; Crevoisier, Cyril; Crill, Patrick; Covey, Kristofer; Frankenberg, Christian; Gedney, Nicola; Höglund-Isaksson, Lena; Ishizawa, Misa; Ito, Akihiko; Joos, Fortunat; Kim, Heon-Sook; Kleinen, Thomas; Krummel, Paul; Lamarque, Jean-François; Langenfelds, Ray; Locatelli, Robin; Machida, Toshinobu; Maksyutov, Shamil; Melton, Joe R.; Morino, Isamu; Naik, Vaishali; O'Doherty, Simon; Parmentier, Frans-Jan W.; Patra, Prabir K.; Peng, Changhui; Peng, Shushi; Peters, Glen P.; Pison, Isabelle; Prinn, Ronald; Ramonet, Michel; Riley, William J.; Saito, Makoto; Santini, Monia; Schroeder, Ronny; Simpson, Isobel J.; Spahni, Renato; Takizawa, Atsushi; Thornton, Brett F.; Tian, Hanqin; Tohjima, Yasunori; Viovy, Nicolas; Voulgarakis, Apostolos; Weiss, Ray; Wilton, David J.; Wiltshire, Andy; Worthy, Doug; Wunch, Debra; Xu, Xiyan; Yoshida, Yukio; Zhang, Bowen; Zhang, Zhen; Zhu, Qiuan

2017-09-01

Following the recent Global Carbon Project (GCP) synthesis of the decadal methane (CH4) budget over 2000-2012 (Saunois et al., 2016), we analyse here the same dataset with a focus on quasi-decadal and inter-annual variability in CH4 emissions. The GCP dataset integrates results from top-down studies (exploiting atmospheric observations within an atmospheric inverse-modelling framework) and bottom-up models (including process-based models for estimating land surface emissions and atmospheric chemistry), inventories of anthropogenic emissions, and data-driven approaches. The annual global methane emissions from top-down studies, which by construction match the observed methane growth rate within their uncertainties, all show an increase in total methane emissions over the period 2000-2012, but this increase is not linear over the 13 years. Despite differences between individual studies, the mean emission anomaly of the top-down ensemble shows no significant trend in total methane emissions over the period 2000-2006, during the plateau of atmospheric methane mole fractions, and also over the period 2008-2012, during the renewed atmospheric methane increase. However, the top-down ensemble mean produces an emission shift between 2006 and 2008, leading to 22 [16-32] Tg CH4 yr-1 higher methane emissions over the period 2008-2012 compared to 2002-2006. This emission increase mostly originated from the tropics, with a smaller contribution from mid-latitudes and no significant change from boreal regions. The regional contributions remain uncertain in top-down studies. Tropical South America and South and East Asia seem to contribute the most to the emission increase in the tropics. However, these two regions have only limited atmospheric measurements and remain therefore poorly constrained. The sectorial partitioning of this emission increase between the periods 2002-2006 and 2008-2012 differs from one atmospheric inversion study to another. However, all top-down studies suggest smaller changes in fossil fuel emissions (from oil, gas, and coal industries) compared to the mean of the bottom-up inventories included in this study. This difference is partly driven by a smaller emission change in China from the top-down studies compared to the estimate in the Emission Database for Global Atmospheric Research (EDGARv4.2) inventory, which should be revised to smaller values in a near future. We apply isotopic signatures to the emission changes estimated for individual studies based on five emission sectors and find that for six individual top-down studies (out of eight) the average isotopic signature of the emission changes is not consistent with the observed change in atmospheric 13CH4. However, the partitioning in emission change derived from the ensemble mean is consistent with this isotopic constraint. At the global scale, the top-down ensemble mean suggests that the dominant contribution to the resumed atmospheric CH4 growth after 2006 comes from microbial sources (more from agriculture and waste sectors than from natural wetlands), with an uncertain but smaller contribution from fossil CH4 emissions. In addition, a decrease in biomass burning emissions (in agreement with the biomass burning emission databases) makes the balance of sources consistent with atmospheric 13CH4 observations. In most of the top-down studies included here, OH concentrations are considered constant over the years (seasonal variations but without any inter-annual variability). As a result, the methane loss (in particular through OH oxidation) varies mainly through the change in methane concentrations and not its oxidants. For these reasons, changes in the methane loss could not be properly investigated in this study, although it may play a significant role in the recent atmospheric methane changes as briefly discussed at the end of the paper.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nyhan, Marguerite; Sobolevsky, Stanislav; Kang, Chaogui

Air pollution related to traffic emissions pose an especially significant problem in cities; this is due to its adverse impact on human health and well-being. Previous studies which have aimed to quantify emissions from the transportation sector have been limited by either simulated or coarsely resolved traffic volume data. Emissions inventories form the basis of urban pollution models, therefore in this study, Global Positioning System (GPS) trajectory data from a taxi fleet of over 15,000 vehicles were analyzed with the aim of predicting air pollution emissions for Singapore. This novel approach enabled the quantification of instantaneous drive cycle parameters inmore » high spatio-temporal resolution, which provided the basis for a microscopic emissions model. Carbon dioxide (CO2), nitrogen oxides (NOx), volatile organic compounds (VOCs) and particulate matter (PM) emissions were thus estimated. Highly localized areas of elevated emissions levels were identified, with a spatio-temporal precision not possible with previously used methods for estimating emissions. Relatively higher emissions areas were mainly concentrated in a few districts that were the Singapore Downtown Core area, to the north of the central urban region and to the east of it. Daily emissions quantified for the total motor vehicle population of Singapore were found to be comparable to another emissions dataset Results demonstrated that high resolution spatio-temporal vehicle traces detected using GPS in large taxi fleets could be used to infer highly localized areas of elevated acceleration and air pollution emissions in cities, and may become a complement to traditional emission estimates, especially in emerging cities and countries where reliable fine-grained urban air quality data is not easily available. This is the first study of its kind to investigate measured microscopic vehicle movement in tandem with microscopic emissions modeling for a substantial study domain.« less

Improved rice residue burning emissions estimates: Accounting for practice-specific emission factors in air pollution assessments of Vietnam.

PubMed

Lasko, Kristofer; Vadrevu, Krishna

2018-05-01

In Southeast Asia and Vietnam, rice residues are routinely burned after the harvest to prepare fields for the next season. Specific to Vietnam, the two prevalent burning practices include: a). piling the residues after hand harvesting; b). burning the residues without piling, after machine harvesting. In this study, we synthesized field and laboratory studies from the literature on rice residue burning emission factors for PM 2.5 . We found significant differences in the resulting burning-practice specific emission factors, with 16.9 g kg -2 (±6.9) for pile burning and 8.8 g kg -2 (±3.5) for non-pile burning. We calculated burning-practice specific emissions based on rice area data, region-specific fuel-loading factors, combined emission factors, and estimates of burning from the literature. Our results for year 2015 estimate 180 Gg of PM 2.5 result from the pile burning method and 130 Gg result from non-pile burning method, with the most-likely current emission scenario of 150 Gg PM 2.5 emissions for Vietnam. For comparison purposes, we calculated emissions using generalized agricultural emission factors employed in global biomass burning studies. These results estimate 80 Gg PM 2.5 , which is only 44% of the pile burning-based estimates, suggesting underestimation in previous studies. We compare our emissions to an existing all-combustion sources inventory, results show emissions account for 14-18% of Vietnam's total PM 2.5 depending on burning practice. Within the highly-urbanized and cloud-covered Hanoi Capital region (HCR), we use rice area from Sentinel-1A to derive spatially-explicit emissions and indirectly estimate residue burning dates. Results from HYSPLIT back-trajectory analysis stratified by season show autumn has most emission trajectories originating in the North, while spring has most originating in the South, suggesting the latter may have bigger impact on air quality. From these results, we highlight locations where emission mitigation efforts could be focused and suggest measures for pollutant mitigation. Our study demonstrates the need to account for emissions variation due to different burning practices. Copyright © 2018 Elsevier Ltd. All rights reserved.

Development of database of real-world diesel vehicle emission factors for China.

PubMed

Shen, Xianbao; Yao, Zhiliang; Zhang, Qiang; Wagner, David Vance; Huo, Hong; Zhang, Yingzhi; Zheng, Bo; He, Kebin

2015-05-01

A database of real-world diesel vehicle emission factors, based on type and technology, has been developed following tests on more than 300 diesel vehicles in China using a portable emission measurement system. The database provides better understanding of diesel vehicle emissions under actual driving conditions. We found that although new regulations have reduced real-world emission levels of diesel trucks and buses significantly for most pollutants in China, NOx emissions have been inadequately controlled by the current standards, especially for diesel buses, because of bad driving conditions in the real world. We also compared the emission factors in the database with those calculated by emission factor models and used in inventory studies. The emission factors derived from COPERT (Computer Programmer to calculate Emissions from Road Transport) and MOBILE may both underestimate real emission factors, whereas the updated COPERT and PART5 (Highway Vehicle Particulate Emission Modeling Software) models may overestimate emission factors in China. Real-world measurement results and emission factors used in recent emission inventory studies are inconsistent, which has led to inaccurate estimates of emissions from diesel trucks and buses over recent years. This suggests that emission factors derived from European or US-based models will not truly represent real-world emissions in China. Therefore, it is useful and necessary to conduct systematic real-world measurements of vehicle emissions in China in order to obtain the optimum inputs for emission inventory models. Copyright © 2015. Published by Elsevier B.V.

Assessment of atmospheric mercury emissions in Finland

PubMed

Mukherjee; Melanen; Ekqvist; Verta

2000-10-02

This paper is part of the study of atmospheric emissions of heavy metals conducted by the Finnish Environment Institute in collaboration with the Technical Research Centre of Finland (VTT) under the umbrella of the Finnish Ministry of the Environment. The scope of our study is limited solely to anthropogenic mercury that is emitted directly to the atmosphere. This article addresses emission factors and trends of atmospheric mercury emissions during the 1990s and is based mainly on the database of the Finnish Environmental Administration. In addition, data based on the measurements taken by the VTT regarding emission factors have been used to estimate emissions of mercury from the incineration of waste. The study indicates that the total emission of mercury has decreased from 1140 kg in 1990 to 620 kg in 1997, while industrial and energy production have been on the increase simultaneously. The 45% emission reduction is due to improved gas cleaning equipment, process changes, automation, the installation of flue gas desulfurization process in coal-fired power plants and strict pollution control laws. In the past, some authors have estimated a higher mercury emission in Finland. In this study, it is also observed that there are no big changes in the quality of raw materials. Estimated emission factors can be of great help to management for estimating mercury emissions and also its risk assessment.

Selection of emission factor standards for estimating emissions from diesel construction equipment in building construction in the Australian context.

PubMed

Zhang, Guomin; Sandanayake, Malindu; Setunge, Sujeeva; Li, Chunqing; Fang, Jun

2017-02-01

Emissions from equipment usage and transportation at the construction stage are classified as the direct emissions which include both greenhouse gas (GHG) and non-GHG emissions due to partial combustion of fuel. Unavailability of a reliable and complete inventory restricts an accurate emission evaluation on construction work. The study attempts to review emission factor standards readily available worldwide for estimating emissions from construction equipment. Emission factors published by United States Environmental Protection Agency (US EPA), Australian National Greenhouse Accounts (AUS NGA), Intergovernmental Panel on Climate Change (IPCC) and European Environmental Agency (EEA) are critically reviewed to identify their strengths and weaknesses. A selection process based on the availability and applicability is then developed to help identify the most suitable emission factor standards for estimating emissions from construction equipment in the Australian context. A case study indicates that a fuel based emission factor is more suitable for GHG emission estimation and a time based emission factor is more appropriate for estimation of non-GHG emissions. However, the selection of emission factor standards also depends on factors like the place of analysis (country of origin), data availability and the scope of analysis. Therefore, suitable modifications and assumptions should be incorporated in order to represent these factors. Copyright © 2016 Elsevier Ltd. All rights reserved.

A Fuel-Based Assessment of On-Road and Off-Road Mobile Source Emission Trends

NASA Astrophysics Data System (ADS)

Dallmann, T. R.; Harley, R. A.

2009-12-01

Mobile sources contribute significantly to emissions of nitrogen oxides (NOx) and fine particulate matter (PM2.5) in the United States. These emissions lead to a variety of environmental concerns including adverse human health effects and climate change. In the electric power sector, sulfur dioxide (SO2) and NOx emissions from power plants are measured directly using continuous emission monitoring systems. In contrast for mobile sources, statistical models are used to estimate average emissions from a very large and diverse population of engines. Despite much effort aimed at improving them, mobile source emission inventories continue to have large associated uncertainties. Alternate methods are needed to help evaluate estimates of mobile source emissions and quantify and reduce the associated uncertainties. In this study, a fuel-based approach is used to estimate emissions from mobile sources, including on-road and off-road gasoline and diesel engines. In this approach, engine activity is measured by fuel consumed (in contrast EPA mobile source emission models are based on vehicle km of travel and total amount of engine work output for on-road and off-road engines, respectively). Fuel consumption is defined in this study based on highway fuel tax reports for on-road engines, and from surveys of fuel wholesalers who sell tax-exempt diesel fuel for use in various off-road sectors such as agriculture, construction, and mining. Over the decade-long time period (1996-2006) that is the focus of the present study, national sales of taxable gasoline and diesel fuel intended for on-road use increased by 15 and 43%, respectively. Diesel fuel use by off-road equipment increased by about 20% over the same time period. Growth in fuel consumption offset some of the reductions in pollutant emission factors that occurred during this period. This study relies on in-use measurements of mobile source emission factors, for example from roadside and tunnel studies, remote sensing, and plume capture experiments. Extensive in-use emissions data are available for NOx, especially for on-road engines. Measurements of exhaust PM2.5 emission factors are sparse in comparison. For NOx, there have been dramatic (factor of 2) decreases in emission factors for on-road gasoline engines between 1996 and 2006, due to use of improved catalytic converters on most engines. In contrast, diesel NOx emission factors decreased more gradually over the same time period. Exhaust PM2.5 emission factors appear to have decreased for most engine categories, but emission uncertainties are large for this pollutant. Pollutant emissions were estimated by combining fuel sales with emission factors expressed per unit of fuel burned. Diesel engines are the dominant mobile source of both NOx and PM2.5; the diesel contribution to NOx has increased over time as gasoline engine emissions have declined. Comparing fuel-based emission estimates with EPA’s national emission inventory led to the following conclusions: (1) total emissions of both NOx and PM2.5 estimated by two different methods were similar, (2) the distribution of source contributions to these totals differ significantly, with higher relative contributions coming from on-road diesel engines in this study compared to EPA.

Examining air pollution in China using production- and consumption-based emissions accounting approaches.

PubMed

Huo, Hong; Zhang, Qiang; Guan, Dabo; Su, Xin; Zhao, Hongyan; He, Kebin

2014-12-16

Two important reasons for China's air pollution are the high emission factors (emission per unit of product) of pollution sources and the high emission intensity (emissions per unit of GDP) of the industrial structure. Therefore, a wide variety of policy measures, including both emission abatement technologies and economic adjustment, must be implemented. To support such measures, this study used the production- and consumption-based emissions accounting approaches to simulate the SO2, NOx, PM2.5, and VOC emissions flows among producers and consumers. This study analyzed the emissions and GDP performance of 36 production sectors. The results showed that the equipment, machinery, and devices manufacturing and construction sectors contributed more than 50% of air pollutant emissions, and most of their products were used for capital formation and export. The service sector had the lowest emission intensities, and its output was mainly consumed by households and the government. In China, the emission intensities of production activities triggered by capital formation and export were approximately twice that of the service sector triggered by final consumption expenditure. This study suggests that China should control air pollution using the following strategies: applying end-of-pipe abatement technologies and using cleaner fuels to further decrease the emission factors associated with rural cooking, electricity generation, and the transportation sector; continuing to limit highly emission-intensive but low value-added exports; developing a plan to reduce construction activities; and increasing the proportion of service GDP in the national economy.

Regulation of Floral Terpenoid Emission and Biosynthesis in Sweet Basil (Ocimum basilicum).

PubMed

Jiang, Yifan; Ye, Jiayan; Li, Shuai; Niinemets, Ülo

2016-12-01

Past studies have focused on the composition of essential oil of Ocimum basilicum leaves, but data on composition and regulation of its aerial emissions, especially floral volatile emissions are scarce. We studied the chemical profile, within-flower spatial distribution (sepals, petals, pistils with stamina and pedicels), diurnal emission kinetics and effects of exogenous methyl jasmonate (MeJA) application on the emission of floral volatiles by dynamic headspace collection and identification using gas chromatography-mass spectrometry (GC-MS) and proton transfer reaction mass spectrometry (PTR-MS). We observed more abundant floral emissions from flowers compared with leaves. Sepals were the main emitters of floral volatiles among the flower parts studied. The emissions of lipoxygenase compounds (LOX) and monoterpenoids, but not sesquiterpene emissions, displayed a diurnal variation driven by light. Response to exogenous MeJA treatment of flowers consisted of a rapid stress response and a longer-term acclimation response. The initial response was associated with enhanced emissions of fatty acid derivatives, monoterpenoids, and sesquiterpenoids without variation of the composition of individual compounds. The longer-term response was associated with enhanced monoterpenoid and sesquiterpenoid emissions with profound changes in the emission spectrum. According to correlated patterns of terpenoid emission changes upon stress, highlighted by a hierarchical cluster analysis, candidate terpenoid synthases responsible for observed diversity and complexity of released terpenoid blends were postulated. We conclude that flower volatile emissions differ quantitatively and qualitatively from leaf emissions, and overall contribute importantly to O. basilicum flavor, especially under stress conditions.

Regulation of Floral Terpenoid Emission and Biosynthesis in Sweet Basil (Ocimum basilicum)

PubMed Central

Jiang, Yifan; Ye, Jiayan; Li, Shuai; Niinemets, Ülo

2018-01-01

Past studies have focused on the composition of essential oil of Ocimum basilicum leaves, but data on composition and regulation of its aerial emissions, especially floral volatile emissions are scarce. We studied the chemical profile, within-flower spatial distribution (sepals, petals, pistils with stamina and pedicels), diurnal emission kinetics and effects of exogenous methyl jasmonate (MeJA) application on the emission of floral volatiles by dynamic headspace collection and identification using gas chromatography-mass spectrometry (GC-MS) and proton transfer reaction mass spectrometry (PTR-MS). We observed more abundant floral emissions from flowers compared with leaves. Sepals were the main emitters of floral volatiles among the flower parts studied. The emissions of lipoxygenase compounds (LOX) and monoterpenoids, but not sesquiterpene emissions, displayed a diurnal variation driven by light. Response to exogenous MeJA treatment of flowers consisted of a rapid stress response and a longer-term acclimation response. The initial response was associated with enhanced emissions of fatty acid derivatives, monoterpenoids, and sesquiterpenoids without variation of the composition of individual compounds. The longer-term response was associated with enhanced monoterpenoid and sesquiterpenoid emissions with profound changes in the emission spectrum. According to correlated patterns of terpenoid emission changes upon stress, highlighted by a hierarchical cluster analysis, candidate terpenoid synthases responsible for observed diversity and complexity of released terpenoid blends were postulated. We conclude that flower volatile emissions differ quantitatively and qualitatively from leaf emissions, and overall contribute importantly to O. basilicum flavor, especially under stress conditions. PMID:29367803

Sesquiterpene emissions from vegetation: a review

NASA Astrophysics Data System (ADS)

Duhl, T. R.; Helmig, D.; Guenther, A.

2007-11-01

This literature review summarizes the environmental controls governing biogenic sesquiterpene (SQT) emissions and presents a compendium of numerous SQT-emitting plant species as well as the quantities and ratios of SQT species they have been observed to emit. The results of many enclosure-based studies indicate that temporal SQT emission variations appear to be dominated mainly by ambient temperatures although other factors contribute (e.g. seasonal variations). This implies that SQT emissions have increased significance at certain times of the year, especially in late spring to mid-summer. The strong temperature dependency of SQT emissions also creates the distinct possibility of increasing SQT emissions in a warmer climate. Disturbances to vegetation (from herbivores and possibly violent weather events) are clearly also important in controlling short-term SQT emissions bursts, though the relative contribution of disturbance-induced emissions is not known. Based on the biogenic SQT emission studies reviewed here, SQT emission rates among numerous species have been observed to cover a wide range of values, and exhibit substantial variability between individuals and across species, as well as at different environmental and phenological states. These emission rates span several orders of magnitude (10s-1000s of ng gDW-1 h-1). Many of the higher rates were reported by early SQT studies, which may have included artificially-elevated SQT emission rates due to higher-than-ambient enclosure temperatures and disturbances to enclosed vegetation prior to and during sample collection. When predicting landscape-level SQT fluxes, modelers must consider the numerous sources of variability driving observed SQT emissions. Characterizations of landscape and global SQT fluxes are highly uncertain given differences and uncertainties in experimental protocols and measurements, the high variability in observed emission rates from different species, the selection of species that have been studied so far, and ambiguities regarding controls over emissions. This underscores the need for standardized experimental protocols, better characterization of disturbance-induced emissions, screening of dominant plant species, and the collection of multiple replicates from several individuals within a given species or genus as well as a better understanding of seasonal dependencies of SQT emissions in order to improve the representation of SQT emission rates.

Sesquiterpene emissions from vegetation: a review

NASA Astrophysics Data System (ADS)

Duhl, T. R.; Helmig, D.; Guenther, A.

2008-05-01

This literature review summarizes the environmental controls governing biogenic sesquiterpene (SQT) emissions and presents a compendium of numerous SQT-emitting plant species as well as the quantities and ratios of SQT species they have been observed to emit. The results of many enclosure-based studies indicate that temporal SQT emission variations appear to be dominated mainly by ambient temperatures although other factors contribute (e.g., seasonal variations). This implies that SQT emissions have increased significance at certain times of the year, especially in late spring to mid-summer. The strong temperature dependency of SQT emissions also creates the distinct possibility of increasing SQT emissions in a warmer climate. Disturbances to vegetation (from herbivores and possibly violent weather events) are clearly also important in controlling short-term SQT emissions bursts, though the relative contribution of disturbance-induced emissions is not known. Based on the biogenic SQT emissions studies reviewed here, SQT emission rates among numerous species have been observed to cover a wide range of values, and exhibit substantial variability between individuals and across species, as well as at different environmental and phenological states. These emission rates span several orders of magnitude (10s-1000s of ng gDW-1 h-1). Many of the higher rates were reported by early SQT studies, which may have included artificially-elevated SQT emission rates due to higher-than-ambient enclosure temperatures and disturbances to enclosed vegetation prior to and during sample collection. When predicting landscape-level SQT fluxes, modelers must consider the numerous sources of variability driving observed SQT emissions. Characterizations of landscape and global SQT fluxes are highly uncertain given differences and uncertainties in experimental protocols and measurements, the high variability in observed emission rates from different species, the selection of species that have been studied so far, and ambiguities regarding controls over emissions. This underscores the need for standardized experimental protocols, better characterization of disturbance-induced emissions, screening of dominant plant species, and the collection of multiple replicates from several individuals within a given species or genus as well as a better understanding of seasonal dependencies of SQT emissions in order to improve the representation of SQT emission rates.

A study to estimate and compare the total particulate matter emission indices (EIN) between traditional jet fuel and two blends of Jet A/Camelina biofuel used in a high by-pass turbofan engine: A case study of Honeywell TFE-109 engine

NASA Astrophysics Data System (ADS)

Shila, Jacob Joshua Howard

The aviation industry is expected to grow at an annual rate of 5% until the year 2031 according to Boeing Outlook Report of 2012. Although the aerospace manufacturers have introduced new aircraft and engines technologies to reduce the emissions generated by aircraft engines, about 15% of all aircraft in 2032 will be using the older technologies. Therefore, agencies such as the National Aeronautics and Astronautics Administration (NASA), Federal Aviation Administration (FAA), the Environmental Protection Agency (EPA) among others together with some academic institutions have been working to characterize both physical and chemical characteristics of the aircraft particulate matter emissions to further understand their effects to the environment. The International Civil Aviation Organization (ICAO) is also working to establish an inventory with Particulate Matter emissions for all the aircraft turbine engines for certification purposes. This steps comes as a result of smoke measurements not being sufficient to provide detailed information on the effects of Particulate Matter (PM) emissions as far as the health and environmental concerns. The use of alternative fuels is essential to reduce the impacts of emissions released by Jet engines since alternative aviation fuels have been studied to lower particulate matter emissions in some types of engines families. The purpose of this study was to determine whether the emission indices of the biofuel blended fuels were lower than the emission indices of the traditional jet fuel at selected engine thrust settings. The biofuel blends observed were 75% Jet A-25% Camelina blend biofuel, and 50% Jet A-50% Jet A blend biofuel. The traditional jet fuel in this study was the Jet A fuel. The results of this study may be useful in establishing a baseline for aircraft engines' PM inventory. Currently the International Civil Aviation Organization (ICAO) engines emissions database contains only gaseous emissions data for only the TFE 731 and JT15D engines' families as representatives of other engines with rated thrust of 6000 pounds or below. The results of this study may be used to add to the knowledge of PM emission data that has been collected in other research studies. This study was quantitative in nature. Three factors were designated which were the types of fuels studied. The TFE-109 turbofan engine was the experimental subject. The independent variable was the engine thrust setting while the response variable was the emission index. Four engine runs were conducted for each fuel. In each engine run, four engine thrust settings were observed. The four engine thrust levels were 10%, 30%, 85%, and 100% rated thrusts levels. Therefore, for each engine thrust settings, there four replicates. The experiments were conducted using a TFE-109 engine test cell located in the Niswonger Aviation Technology building at the Purdue University Airport. The testing facility has the capability to conduct the aircraft PM emissions tests. Due to the equipment limitations, the study was limited to observe total PM emissions instead of specifically measuring the non-volatile PM emissions. The results indicate that the emissions indices of the blended biofuels were not statistically significantly lower compared to the emissions of the traditional jet fuel at rated thrust levels of 100% and 85% of TFE-109 turbofan engine. However, the emission indices for the 50%Jet A - 50%Camelina biofuel blend were statistically significantly lower compared to the emission indices of the 100% Jet A fuel at 10% and 30% engine rated thrusts levels of TFE-109 engine. The emission indices of the 50%-50% biofuel blend were lower by reductions of 15% and 17% at engine rated thrusts of 10% and 30% respectively compared to the emissions indices of the traditional jet fuel at the same engine thrust levels. Experimental modifications in future studies may provide estimates of the emissions indices range for this particular engine these estimates may be used to estimate the levels of PM emissions for other similar engines. Additional measurements steps such as heating of the sampling line, sampling dilution application, sampling line loss estimates, and calculations of the sampling line PM residence times will also be useful future results.

Structural properties of ultrafine Ba-hexaferrite nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Makovec, Darko, E-mail: Darko.Makovec@ijs.si; Primc, Darinka; Sturm, Saso

2012-12-15

Crystal structure of ultrafine Ba-hexaferrite (BaFe{sub 12}O{sub 19}) nanoparticles was studied using X-ray diffractometry (XRD), high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDXS), X-ray absorption fine structure (XAFS), and Moessbauer spectroscopy (MS), to be compared to the structure of larger nanoparticles and the bulk. The nanoparticles were synthesized with hydrothermal treatment of an appropriate suspension of Ba and Fe hydroxides in the presence of a large excess of OH{sup -}. The ultrafine nanoparticles were formed in a discoid shape, {approx}10 nm wide and only {approx}3 nm thick, comparable to the size of the hexagonal unit cell in the c-direction.more » The HRTEM image analysis confirmed the hexaferrite structure, whereas EDXS showed the composition matching the BaFe{sub 12}O{sub 19} formula. XAFS and MS analyses showed considerable disorder of the structure, most probably responsible for the low magnetization. - Graphical abstract: Left: HREM image of an ultrafine Ba-hexaferrite nanoparticle (inset: TEM image of the nanoparticles); Right: the experimental HRTEM image is compared with calculated image and corresponding atomic model. Highlights: Black-Right-Pointing-Pointer Crystal structure of ultrafine Ba-hexaferrite (BaFe{sub 12}O{sub 19}) nanoparticles was compared to the structure of the bulk. Black-Right-Pointing-Pointer Thickness the discoid nanoparticles was comparable to the size of the hexagonal unit cell in the c-direction. Black-Right-Pointing-Pointer Considerable disorder of the nanoparticles' structure is most probably responsible for their low magnetization.« less

Evaluating measurements of carbon dioxide emissions using a precision source--A natural gas burner.

PubMed

Bryant, Rodney; Bundy, Matthew; Zong, Ruowen

2015-07-01

A natural gas burner has been used as a precise and accurate source for generating large quantities of carbon dioxide (CO2) to evaluate emissions measurements at near-industrial scale. Two methods for determining carbon dioxide emissions from stationary sources are considered here: predicting emissions based on fuel consumption measurements-predicted emissions measurements, and direct measurement of emissions quantities in the flue gas-direct emissions measurements. Uncertainty for the predicted emissions measurement was estimated at less than 1%. Uncertainty estimates for the direct emissions measurement of carbon dioxide were on the order of ±4%. The relative difference between the direct emissions measurements and the predicted emissions measurements was within the range of the measurement uncertainty, therefore demonstrating good agreement. The study demonstrates how independent methods are used to validate source emissions measurements, while also demonstrating how a fire research facility can be used as a precision test-bed to evaluate and improve carbon dioxide emissions measurements from stationary sources. Fossil-fuel-consuming stationary sources such as electric power plants and industrial facilities account for more than half of the CO2 emissions in the United States. Therefore, accurate emissions measurements from these sources are critical for evaluating efforts to reduce greenhouse gas emissions. This study demonstrates how a surrogate for a stationary source, a fire research facility, can be used to evaluate the accuracy of measurements of CO2 emissions.

Characteristics of typical non-road machinery emissions in China by using portable emission measurement system.

PubMed

Fu, Mingliang; Ge, Yunshan; Tan, Jianwei; Zeng, Tao; Liang, Bin

2012-10-15

Non-road machinery, especially construction equipment could be an important pollutant source of the deterioration in air quality in Chinese urban areas due to its large quantity and to the absence of stringent emission requirements. In this study, emission tests were performed on 12 excavators and 8 wheel loaders by using portable emission measurement system (PEMS) to determine their emission characteristics. The typical operating modes were categorized as idling mode, moving mode and working mode. Compared with those during idling and moving modes, the average time-based emission factors during working mode of HC were 2.61 and 1.27 times higher, NO(x) were 3.66 and 1.36 times higher, and PM were 4.05 and 1.95 times higher, respectively. Under all conditions, categories of the measured emissions increased with the rise in engine power. Compared with those of Stage I emission standard equipment, gaseous emissions and PM emitted from Stage II emission standard equipment were lower. The results indicated that, from Stage I to Stage II, the average reductions of HC, NO(x) and PM were 56%, 37% and 29% for the working mode, respectively. Those results also demonstrated the effectiveness of emission control regulation and the improvement of emission control technology. The data and tests show that the longer the accumulated working hours, the higher HC and NO(x) average fuel-based emission factors are. The emissions measured from the construction vehicles employed in this study were higher than the data collected in previous studies, which shows that it is critical for the government to put into effect more stringent emission regulations to further improve the air quality in Chinese urban areas. Copyright © 2012 Elsevier B.V. All rights reserved.

Mercury emission estimates from fires: an initial inventory for the United States.

PubMed

Wiedinmyer, Christine; Friedli, Hans

2007-12-01

Recent studies have shown that emissions of mercury (Hg), a hazardous air pollutant, from fires can be significant. However, to date, these emissions have not been well-quantified for the entire United States. Daily emissions of Hg from fires in the lower 48 states of the United States (LOWER48) and in Alaska were estimated for 2002-2006 using a simple fire emissions model. Emission factors of Hg from fires in different ecosystems were compiled from published plume studies and from soil-based assessments. Annual averaged emissions of Hg from fires in the LOWER48 and Alaska were 44 (20-65) metric tons yr(-1), equivalent to approximately 30% of the U.S. EPA 2002 National Emissions Inventory for Hg. Alaska had the highest averaged monthly emissions of all states; however, the emissions have a high temporal variability. Emissions from forests dominate the inventory, suggesting that Hg emissions from agricultural fires are not significant on an annual basis. The uncertainty in the Hg emission factors due to limited data leads to an uncertainty in the emission estimates on the order of +/-50%. Research is still needed to better constrain Hg emission factors from fires, particularly in the eastern U.S. and for ecosystems other than forests.

Determining the Leaf Emissivity of Three Crops by Infrared Thermometry

PubMed Central

Chen, Chiachung

2015-01-01

Plant temperature can provide important physiological information for crop management. Non-contact measurement with an infrared thermometer is useful for detecting leaf temperatures. In this study, a novel technique was developed to measure leaf emissivity using an infrared thermometer with an infrared sensor and a thermocouple wire. The measured values were transformed into true temperatures by calibration equations to improve the measurement accuracy. The relationship between two kinds of measurement temperatures and setting emissivities was derived as a model for calculating of true emissivity. The emissivities of leaves of three crops were calculated by the mathematical equation developed in this study. The mean emissivities were 0.9809, 0.9783, 0.981 and 0.9848 for Phalaenopsis mature and new leaves and Paphiopedilum and Malabar chestnut leaves, respectively. Emissivity differed significantly between leaves of Malabar chestnut and the two orchids. The range of emissivities determined in this study was similar to that in the literature. The precision of the measurement is acceptable. The method developed in this study is a real-time, in situ technique and could be used for agricultural and forestry plants. PMID:25988870

A technology-based mass emission factors of gases and aerosol precursor and spatial distribution of emissions from on-road transport sector in India

NASA Astrophysics Data System (ADS)

Prakash, Jai; Habib, Gazala

2018-05-01

This study presents a new emission estimate of gaseous pollutants including CO, CO2, and NOX from on-road transport sector of India for the base year 2013. For the first time, a detailed vintage-wise on-road measured emission factors used for reducing uncertainties in emission estimates. The consumptions of diesel, gasoline, and compressed natural gas (CNG) were also estimated at the national level and disaggregated at the state level. The national average use of diesel, gasoline, and CNG and their 95% confidence interval estimated as 52 (39-66), 24 (18-30), and 1.6 (1.2-2.0) MTy-1 for the year 2013. The CO, CO2, and NOX emissions were estimated as 7349 (3220-11477) Gg y-1, 261 (179-343) Tg y-1, and 4052 (2127-5977) Gg y-1, respectively from on-road transport sector for the year 2013. New vehicles registered after 2005 emit 70-80% of national level CO2, and NOX, while rest 20-30% were emitted by old vehicles registered before 2005. Old and new vehicles both equally contributed to CO emissions. Superemitters accounted for 14% of total traffic volume, but they were responsible for 17-57% of total CO2, CO and NOX emissions. The uncertainties in emission estimates were reduced to 48-56% compared to previous estimates (62-136%). The comparison with recent studies for nationwide emission estimates from 4-wheelers indicated that use of emission factors from dynamometer studies can underestimate the emissions by 32-92% for various pollutants, while an overestimation by 20-82% was seen with the use of emission model derived emission factors. Similarly for Delhi city recent CO and NOx emission estimates for 4-wheelers based on emission factors reported from dynamometer studies were 23-89% lower than present work. The present work revealed the need for representative vintage wise emission factor database development from on-road measurement and the more comprehensive assessment of activity data through survey.

Effect of climate-driven changes in species composition on regional emission capacities of biogenic compounds

NASA Astrophysics Data System (ADS)

Schurgers, G.; Arneth, A.; Hickler, T.

2011-11-01

Regional or global modeling studies of dynamic vegetation often represent vegetation by large functional units (plant functional types (PFTs)). For simulation of biogenic volatile organic compounds (BVOC) in these models, emission capacities, which give the emission under standardized conditions, are provided as an average value for a PFT. These emission capacities thus hide the known heterogeneity in emission characteristics that are not straightforwardly related to functional characteristics of plants. Here we study the effects of the aggregation of species-level information on emission characteristics at PFT level. The roles of temporal and spatial variability are assessed for Europe by comparing simulations that represent vegetation by dominant tree species on the one hand and by plant functional types on the other. We compare a number of time slices between the Last Glacial Maximum (21,000 years ago) and the present day to quantify the effects of dynamically changing vegetation on BVOC emissions. Spatial heterogeneity of emission factors is studied with present-day simulations. We show that isoprene and monoterpene emissions are of similar magnitude in Europe when the simulation represents dominant European tree species, which indicates that simulations applying typical global-scale emission capacities for PFTs tend to overestimate isoprene and underestimate monoterpene emissions. Moreover, both spatial and temporal variability affect emission capacities considerably, and by aggregating these to PFT level averages, one loses the information on local heterogeneity. Given the reactive nature of these compounds, accounting for spatial and temporal heterogeneity can be important for studies of their fate in the atmosphere.

Alternative industrial carbon emissions benchmark based on input-output analysis

NASA Astrophysics Data System (ADS)

Han, Mengyao; Ji, Xi

2016-12-01

Some problems exist in the current carbon emissions benchmark setting systems. The primary consideration for industrial carbon emissions standards highly relate to direct carbon emissions (power-related emissions) and only a portion of indirect emissions are considered in the current carbon emissions accounting processes. This practice is insufficient and may cause double counting to some extent due to mixed emission sources. To better integrate and quantify direct and indirect carbon emissions, an embodied industrial carbon emissions benchmark setting method is proposed to guide the establishment of carbon emissions benchmarks based on input-output analysis. This method attempts to link direct carbon emissions with inter-industrial economic exchanges and systematically quantifies carbon emissions embodied in total product delivery chains. The purpose of this study is to design a practical new set of embodied intensity-based benchmarks for both direct and indirect carbon emissions. Beijing, at the first level of carbon emissions trading pilot schemes in China, plays a significant role in the establishment of these schemes and is chosen as an example in this study. The newly proposed method tends to relate emissions directly to each responsibility in a practical way through the measurement of complex production and supply chains and reduce carbon emissions from their original sources. This method is expected to be developed under uncertain internal and external contexts and is further expected to be generalized to guide the establishment of industrial benchmarks for carbon emissions trading schemes in China and other countries.

Assessment of methane emissions from oil and gas production pads using mobile measurements.

PubMed

Brantley, Halley L; Thoma, Eben D; Squier, William C; Guven, Birnur B; Lyon, David

2014-12-16

A new mobile methane emissions inspection approach, Other Test Method (OTM) 33A, was used to quantify short-term emission rates from 210 oil and gas production pads during eight two-week field studies in Texas, Colorado, and Wyoming from 2010 to 2013. Emission rates were log-normally distributed with geometric means and 95% confidence intervals (CIs) of 0.33 (0.23, 0.48), 0.14 (0.11, 0.19), and 0.59 (0.47, 0.74) g/s in the Barnett, Denver-Julesburg, and Pinedale basins, respectively. This study focused on sites with emission rates above 0.01 g/s and included short-term (i.e., condensate tank flashing) and maintenance-related emissions. The results fell within the upper ranges of the distributions observed in recent onsite direct measurement studies. Considering data across all basins, a multivariate linear regression was used to assess the relationship of methane emissions to well age, gas production, and hydrocarbon liquids (oil or condensate) production. Methane emissions were positively correlated with gas production, but only approximately 10% of the variation in emission rates was explained by variation in production levels. The weak correlation between emission and production rates may indicate that maintenance-related stochastic variables and design of production and control equipment are factors determining emissions.

Improved Mechanistic Understanding of Natural Gas Methane Emissions from Spatially Resolved Aircraft Measurements

DOE PAGES

Schwietzke, Stefan; Pétron, Gabrielle; Conley, Stephen; ...

2017-06-05

Divergence in recent oil and gas related methane emission estimates between aircraft studies (basin total for a midday window) and emissions inventories (annualized regional and national statistics) indicate the need for better understanding the experimental design, including temporal and spatial alignment and interpretation of results. In our aircraft-based methane emission estimates in a major U.S. shale gas basin resolved from west to east show (i) similar spatial distributions for 2 days, (ii) strong spatial correlations with reported NG production (R 2 = 0.75) and active gas well pad count (R 2 = 0.81), and (iii) 2× higher emissions in themore » western half (normalized by gas production) despite relatively homogeneous dry gas and well characteristics. Operator reported hourly activity data show that midday episodic emissions from manual liquid unloadings (a routine operation in this basin and elsewhere) could explain ~1/3 of the total emissions detected midday by the aircraft and ~2/3 of the west–east difference in emissions. The 22% emission difference between both days further emphasizes that episodic sources can substantially impact midday methane emissions and that aircraft may detect daily peak emissions rather than daily averages that are generally employed in emissions inventories. And while the aircraft approach is valid, quantitative, and independent, this study sheds new light on the interpretation of previous basin scale aircraft studies, and provides an improved mechanistic understanding of oil and gas related methane emissions.« less

Improved Mechanistic Understanding of Natural Gas Methane Emissions from Spatially Resolved Aircraft Measurements.

PubMed

Schwietzke, Stefan; Pétron, Gabrielle; Conley, Stephen; Pickering, Cody; Mielke-Maday, Ingrid; Dlugokencky, Edward J; Tans, Pieter P; Vaughn, Tim; Bell, Clay; Zimmerle, Daniel; Wolter, Sonja; King, Clark W; White, Allen B; Coleman, Timothy; Bianco, Laura; Schnell, Russell C

2017-06-20

Divergence in recent oil and gas related methane emission estimates between aircraft studies (basin total for a midday window) and emissions inventories (annualized regional and national statistics) indicate the need for better understanding the experimental design, including temporal and spatial alignment and interpretation of results. Our aircraft-based methane emission estimates in a major U.S. shale gas basin resolved from west to east show (i) similar spatial distributions for 2 days, (ii) strong spatial correlations with reported NG production (R 2 = 0.75) and active gas well pad count (R 2 = 0.81), and (iii) 2× higher emissions in the western half (normalized by gas production) despite relatively homogeneous dry gas and well characteristics. Operator reported hourly activity data show that midday episodic emissions from manual liquid unloadings (a routine operation in this basin and elsewhere) could explain ∼1/3 of the total emissions detected midday by the aircraft and ∼2/3 of the west-east difference in emissions. The 22% emission difference between both days further emphasizes that episodic sources can substantially impact midday methane emissions and that aircraft may detect daily peak emissions rather than daily averages that are generally employed in emissions inventories. While the aircraft approach is valid, quantitative, and independent, our study sheds new light on the interpretation of previous basin scale aircraft studies, and provides an improved mechanistic understanding of oil and gas related methane emissions.

Evaluation of On-Road Vehicle Emission Trends in the United States

NASA Astrophysics Data System (ADS)

Harley, R. A.; Dallmann, T. R.; Kirchstetter, T.

2010-12-01

Mobile sources contribute significantly to emissions of nitrogen oxides (NOx), carbon monoxide (CO), fine particulate matter (PM2.5), and black carbon (BC). These emissions lead to a variety of environmental problems including air pollution and climate change. At present, national and state-level mobile source emission inventories are developed using statistical models to predict emissions from large and diverse populations of vehicles. Activity is measured by total vehicle-km traveled, and pollutant emission factors are predicted based on laboratory testing of individual vehicles. Despite efforts to improve mobile source emission inventories, they continue to have large associated uncertainties. Alternate methods, such as the fuel-based approach used here, are needed to evaluate estimates of mobile source emissions and to help reduce uncertainties. In this study we quantify U.S. national emissions of NOx, CO, PM2.5, and BC from on-road diesel and gasoline vehicles for the years 1990-2010, including effects of a weakened national economy on fuel sales and vehicle travel from 2008-10. Pollutant emissions are estimated by multiplying total amounts of fuel consumed with emission factors expressed per unit of fuel burned. Fuel consumption is used as a measure of vehicle activity, and is based on records of taxable fuel sales. Pollutant emission factors are derived from roadside and tunnel studies, remote sensing measurements, and individual vehicle exhaust plume capture experiments. Emission factors are updated with new results from a summer 2010 field study conducted at the Caldecott tunnel in the San Francisco Bay Area.

Improved Mechanistic Understanding of Natural Gas Methane Emissions from Spatially Resolved Aircraft Measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schwietzke, Stefan; Pétron, Gabrielle; Conley, Stephen

Divergence in recent oil and gas related methane emission estimates between aircraft studies (basin total for a midday window) and emissions inventories (annualized regional and national statistics) indicate the need for better understanding the experimental design, including temporal and spatial alignment and interpretation of results. In our aircraft-based methane emission estimates in a major U.S. shale gas basin resolved from west to east show (i) similar spatial distributions for 2 days, (ii) strong spatial correlations with reported NG production (R 2 = 0.75) and active gas well pad count (R 2 = 0.81), and (iii) 2× higher emissions in themore » western half (normalized by gas production) despite relatively homogeneous dry gas and well characteristics. Operator reported hourly activity data show that midday episodic emissions from manual liquid unloadings (a routine operation in this basin and elsewhere) could explain ~1/3 of the total emissions detected midday by the aircraft and ~2/3 of the west–east difference in emissions. The 22% emission difference between both days further emphasizes that episodic sources can substantially impact midday methane emissions and that aircraft may detect daily peak emissions rather than daily averages that are generally employed in emissions inventories. And while the aircraft approach is valid, quantitative, and independent, this study sheds new light on the interpretation of previous basin scale aircraft studies, and provides an improved mechanistic understanding of oil and gas related methane emissions.« less

Characteristics of On-road Diesel Vehicles: Black Carbon Emissions in Chinese Cities Based on Portable Emissions Measurement.

PubMed

Zheng, Xuan; Wu, Ye; Jiang, Jingkun; Zhang, Shaojun; Liu, Huan; Song, Shaojie; Li, Zhenhua; Fan, Xiaoxiao; Fu, Lixin; Hao, Jiming

2015-11-17

Black carbon (BC) emissions from heavy-duty diesel vehicles (HDDVs) are rarely continuously measured using portable emission measurement systems (PEMSs). In this study, we utilize a PEMS to obtain real-world BC emission profiles for 25 HDDVs in China. The average fuel-based BC emissions of HDDVs certified according to Euro II, III, IV, and V standards are 2224 ± 251, 612 ± 740, 453 ± 584, and 152 ± 3 mg kg(-1), respectively. Notably, HDDVs adopting mechanical pump engines had significantly higher BC emissions than those equipped with electronic injection engines. Applying the useful features of PEMSs, we can relate instantaneous BC emissions to driving conditions using an operating mode binning methodology, and the average emission rates for Euro II to Euro IV diesel trucks can be constructed. From a macroscopic perspective, we observe that average speed is a significant factor affecting BC emissions and is well correlated with distance-based emissions (R(2) = 0.71). Therefore, the average fuel-based and distance-based BC emissions on congested roads are 40 and 125% higher than those on freeways. These results should be taken into consideration in future emission inventory studies.

The Effect of Framing and Normative Messages in Building Support for Climate Policies

PubMed Central

Hurlstone, Mark J.; Lewandowsky, Stephan; Newell, Ben R.; Sewell, Brittany

2014-01-01

Deep cuts in greenhouse gas emissions are required to mitigate climate change. However, there is low willingness amongst the public to prioritise climate policies for reducing emissions. Here we show that the extent to which Australians are prepared to reduce their country's CO2 emissions is greater when the costs to future national income are framed as a “foregone-gain”—incomes rise in the future but not by as much as in the absence of emission cuts—rather than as a “loss”—incomes decrease relative to the baseline expected future levels (Studies 1 & 2). The provision of a normative message identifying Australia as one of the world's largest CO2 emitters did not increase the amount by which individuals were prepared to reduce emissions (Study 1), whereas a normative message revealing the emission policy preferences of other Australians did (Study 2). The results suggest that framing the costs of reducing emissions as a smaller increase in future income and communicating normative information about others' emission policy preferences are effective methods for leveraging public support for emission cuts. PMID:25501009

The effect of framing and normative messages in building support for climate policies.

PubMed

Hurlstone, Mark J; Lewandowsky, Stephan; Newell, Ben R; Sewell, Brittany

2014-01-01

Deep cuts in greenhouse gas emissions are required to mitigate climate change. However, there is low willingness amongst the public to prioritise climate policies for reducing emissions. Here we show that the extent to which Australians are prepared to reduce their country's CO2 emissions is greater when the costs to future national income are framed as a "foregone-gain"--incomes rise in the future but not by as much as in the absence of emission cuts--rather than as a "loss"--incomes decrease relative to the baseline expected future levels (Studies 1 & 2). The provision of a normative message identifying Australia as one of the world's largest CO2 emitters did not increase the amount by which individuals were prepared to reduce emissions (Study 1), whereas a normative message revealing the emission policy preferences of other Australians did (Study 2). The results suggest that framing the costs of reducing emissions as a smaller increase in future income and communicating normative information about others' emission policy preferences are effective methods for leveraging public support for emission cuts.

Estimating the Additional Greenhouse Gas Emissions in Korea: Focused on Demolition of Asbestos Containing Materials in Building

PubMed Central

Kim, Young-Chan; Hong, Won-Hwa; Zhang, Yuan-Long; Son, Byeung-Hun; Seo, Youn-Kyu; Choi, Jun-Ho

2016-01-01

When asbestos containing materials (ACM) must be removed from the building before demolition, additional greenhouse gas (GHG) emissions are generated. However, precedent studies have not considered the removal of ACM from the building. The present study aimed to develop a model for estimating GHG emissions created by the ACM removal processes, specifically the removal of asbestos cement slates (ACS). The second objective was to use the new model to predict the total GHG emission produced by ACM removal in the entire country of Korea. First, an input-equipment inventory was established for each step of the ACS removal process. Second, an energy consumption database for each equipment type was established. Third, the total GHG emission contributed by each step of the process was calculated. The GHG emissions generated from the 1,142,688 ACS-containing buildings in Korea was estimated to total 23,778 tonCO2eq to 132,141 tonCO2eq. This study was meaningful in that the emissions generated by ACS removal have not been studied before. Furthermore, the study deals with additional problems that can be triggered by the presence of asbestos in building materials. The method provided in this study is expected to contribute greatly to the calculation of GHG emissions caused by ACM worldwide. PMID:27626433

Mitigation options for methane emissions from rice fields in the Philippines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lantin, R.S.; Buendia, L.V.; Wassmann, R.

1996-12-31

The contribution of Philippine rice production to global methane emission and breakthroughs in methane emission studies conducted in the country are presented in this paper. A significant impact in the reduction of GHG emissions from agriculture can be achieved if methane emissions from ricefields can be abated. This study presents the contribution of Philippine rice cultivation to global methane emission and breakthroughs in methane emission studies in the country which address the issue of mitigation. Using the derived emission factors from local measurements, rice cultivation contributes 566.6 Gg of methane emission in the Philippines. This value is 62% of themore » total methane emitted from the agriculture sector. The emission factors employed which are 78% of the IPCC value for irrigated rice and 95% for rainfed rice were derived from measurements with an automatic system taken during the growth duration in the respective ecosystems. Plots drained for 2 weeks at midtillering and before harvest gave a significant reduction in methane emission as opposed to continuously flooded plots and plots drained before harvest. The cultivar Magat reduced methane emission by 50% as compared to the check variety IR72. The application of ammonium sulfate instead of urea reduced methane emission by 10% to 34%. Addition of 6 t ha{sup {minus}1} phosphogypsum in combination with urea reduced emission by 74% as opposed to plots applied with urea alone. It is also from the results of such measurements that abatement strategies are based as regards to modifying treatments such as water management, fertilization, and choice of rice variety. It is not easy to identify and recommend mitigation strategies that will fit a particular cropping system. However, the identified mitigation options provide focus for the abatement of methane emission from ricefields.« less

A comparison of greenhouse gas emissions and local area pollution of highspeed rail and air travel between Los Angeles and Las Vegas

NASA Astrophysics Data System (ADS)

Mullins, Damien

Global warming is one of the most discussed global environmental issues in the world today. Global warming is driven by fossil fuel combustion emissions known as Green-house Gases (GHG). One of the major contributors to GHG emissions is the transport sector, emitting approximately 30% of total U.S. CO 2 emissions in 2010. Air travel contributed approximately 3.5% of total U.S. CO2 in 2008. High-speed Rail (HSR) is often touted as cleaner, more sustainable mode of transport than air travel. HSR is one of few modes of transport capable of competing with air travel for short to medium-haul distances. There has been considerable study of GHG emissions of each independently. Research has also been carried out into the economics and competition of these transport modes. However, there has been very limited study of the comparative emissions of each, apart from one study in Europe (Givoni, 2007). The current study was undertaken with the goal of quantifying potential emission savings due to mode substitution from air travel to HSR in the Los Angeles to Las Vegas corridor. This study only considered the emissions which occurred from the combustion of the relevant fuels, either in power plants or the engines of an aircraft. Emissions from fuel production/refining or transport of fuels were not considered. Another issue compared was Local Area Pollution (LAP), which is a measure of the severity of emissions effect on the environment. This was examined because all emissions from HSR occur close to the surface of the earth, and hence effect the local environment, while only a portion of aircraft emissions do. This study was carried out using internationally recognized emission inventory methodologies. For the air travel emission estimate methodologies and data published by the Intergovernmental Panel on Climate Change (IPCC) and the International Civil Aviation Organization (ICAO) were used. The HSR energy use was estimated from energy use data from currently running HSR programs, in France, UK and Spain (Alvarez, 2007; Kemp, 2007). The emissions were then estimated using an adjusted tier 3 method. For aviation emissions a tier three method was also used. The findings of this research are mixed. HSR would emit 66% less GHG emissions using today's energy mixes for California and Nevada. Using California's 2020 target energy mix HSR would emit 80% less GHG emissions. However, using today's energy mix HSR would cause 33% more LAP than air travel. Using California's 2020 mix the HSR would cause 22% less LAP the air travel. However this 20% improvement would likely be eroded by aircraft emissions improvement between now and 2020. To conclude, this research found that HSR does offer significant GHG emission reductions, when compared to air travel between Los Angeles and Las Vegas. However is less clear regarding LAP, though HSR has the potential to create savings here in the future as well. For other corridors around the U.S.A., earmarked for HSR, similar studies should be carried out to examine the benefits of such mode transfer.

Quantifying VOC emissions from polymers: A case study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schulze, J.K.; Qasem, J.S.; Snoddy, R.

1996-12-31

Evaluating residual volatile organic compound emissions emanating from low-density polyethylene can pose significant challenges. These challenges include quantifying emissions from: (a) multiple process lines with different operating conditions; (b) several different comonomers; (c) variations of comonomer content in each grade; and (d) over 120 grades of LDPE. This presentation is a Case Study outlining a project to develop grade-specific emission data for low-density polyethylene pellets. This study included extensive laboratory analyses and required the development of a relational database to compile analytical results, calculate the mean concentration and standard deviation, and generate emissions reports.

Diesel bus emissions measured in a tunnel study.

PubMed

Jamriska, Milan; Morawska, Lidia; Thomas, Steven; He, Congrong

2004-12-15

The emission factors of a bus fleet consisting of approximately 300 diesel-powered buses were measured in a tunnel study under well-controlled conditions during a 2-d monitoring campaign in Brisbane. Particle number and mass concentration levels of submicrometer particles and PM2.5 were monitored by SMPS and DustTrak instruments at the tunnel's entrance and exit, respectively. Correlation between DustTrak and TEOM response to diesel emissions was assessed, and the DustTrak results were recalculated into TEOM equivalent data. The mean value of the number and mass emission factors was (3.11+/-2.41) x 10(14) particles km(-1) for submicrometer particles and 583+/-451 mg km(-1) for PM2.5 (DustTrak), respectively. TEOM PM2.5 equivalent emission factor was 267+/-207 mg km(-1). The results are in good agreement with the emission factors determined from steady-state dynamometer testing of 12 buses from the same Brisbane City bus fleet. The results indicate that when carefully designed, both approaches, the dynamometer and on-road studies, can provide comparable results, applicable for the assessment of the effect of traffic emissions on airborne particle pollution. A brief overview of emission factors determined from other on-road and dynamometer studies reported in the literature as well as with the regulatory values used for the vehicle emission inventory assessment is presented and compared with the results obtained in this study.

Improved Rice Residue Burning Emissions Estimates: Accounting for Practice-Specific Emission Factors in Air Pollution Assessments of Vietnam

NASA Technical Reports Server (NTRS)

Lasko, Kristofer; Vadrevu, Krishna

2018-01-01

In Southeast Asia and Vietnam, rice residues are routinely burned after the harvest to prepare fields for the next season. Specific to Vietnam, the two prevalent burning practices include: a). piling the residues after hand harvesting; b). burning the residues without piling, after machine harvesting. In this study, we synthesized field and laboratory studies from the literature on rice residue burning emission factors for Particulate Matter less than 2.5 microns (PM2.5). We found significant differences in the resulting burning-practice specific emission factors, with 16.9 grams per square kilogram (plus or minus 6.9) for pile burning and 8.8 grams per square kilogram (plus or minus 3.5) for non-pile burning. We calculated burning practice specific emissions based on rice area data, region-specific fuel-loading factors, combined emission factors, and estimates of burning from the literature. Our results for year 2015 estimate 180 gigagrams of PM2.5 result from the pile burning method and 130 gigagrams result from non-pile burning method, with the most-likely current emission scenario of 150 gigagrams PM2.5 emissions for Vietnam. For comparison purposes, we calculated emissions using generalized agricultural emission factors employed in global biomass burning studies. These results estimate 80 gigagrams PM2.5, which is only 44 percent of the pile burning-based estimates, suggesting underestimation in previous studies. We compare our emissions to an existing all-combustion sources inventory, results show emissions account for 14-18 percent of Vietnam's total PM2.5 depending on burning practice. Within the highly-urbanized and cloud-covered Hanoi Capital region (HCR), we use rice area from Sentinel-1A to derive spatially-explicit emissions and indirectly estimate residue burning dates. Results from HYSPLIT (Hybrid Single-Particle Lagrangian Integrated Trajectory) back-trajectory analysis stratified by season show autumn has most emission trajectories originating in the North, while spring has most originating in the South, suggesting the latter may have bigger impact on air quality. From these results, we highlight locations where emission mitigation efforts could be focused and suggest measures for pollutant mitigation. Our study demonstrates the need to account for emissions variation due to different burning practices.

Assessing Uncertainties in Gridded Emissions: A Case Study for Fossil Fuel Carbon Dioxide (FFCO2) Emission Data

NASA Technical Reports Server (NTRS)

Oda, T.; Ott, L.; Lauvaux, T.; Feng, S.; Bun, R.; Roman, M.; Baker, D. F.; Pawson, S.

2017-01-01

Fossil fuel carbon dioxide (CO2) emissions (FFCO2) are the largest input to the global carbon cycle on a decadal time scale. Because total emissions are assumed to be reasonably well constrained by fuel statistics, FFCO2 often serves as a reference in order to deduce carbon uptake by poorly understood terrestrial and ocean sinks. Conventional atmospheric CO2 flux inversions solve for spatially explicit regional sources and sinks and estimate land and ocean fluxes by subtracting FFCO2. Thus, errors in FFCO2 can propagate into the final inferred flux estimates. Gridded emissions are often based on disaggregation of emissions estimated at national or regional level. Although national and regional total FFCO2 are well known, gridded emission fields are subject to additional uncertainties due to the emission disaggregation. Assessing such uncertainties is often challenging because of the lack of physical measurements for evaluation. We first review difficulties in assessing uncertainties associated with gridded FFCO2 emission data and present several approaches for evaluation of such uncertainties at multiple scales. Given known limitations, inter-emission data differences are often used as a proxy for the uncertainty. The popular approach allows us to characterize differences in emissions, but does not allow us to fully quantify emission disaggregation biases. Our work aims to vicariously evaluate FFCO2 emission data using atmospheric models and measurements. We show a global simulation experiment where uncertainty estimates are propagated as an atmospheric tracer (uncertainty tracer) alongside CO2 in NASA's GEOS model and discuss implications of FFCO2 uncertainties in the context of flux inversions. We also demonstrate the use of high resolution urban CO2 simulations as a tool for objectively evaluating FFCO2 data over intense emission regions. Though this study focuses on FFCO2 emission data, the outcome of this study could also help improve the knowledge of similar gridded emissions data for non-CO2 compounds with similar emission characteristics.

Assessing uncertainties in gridded emissions: A case study for fossil fuel carbon dioxide (FFCO2) emission data

NASA Astrophysics Data System (ADS)

Oda, T.; Ott, L. E.; Lauvaux, T.; Feng, S.; Bun, R.; Roman, M. O.; Baker, D. F.; Pawson, S.

2017-12-01

Fossil fuel carbon dioxide (CO2) emissions (FFCO2) are the largest input to the global carbon cycle on a decadal time scale. Because total emissions are assumed to be reasonably well constrained by fuel statistics, FFCO2 often serves as a reference in order to deduce carbon uptake by poorly understood terrestrial and ocean sinks. Conventional atmospheric CO2 flux inversions solve for spatially explicit regional sources and sinks and estimate land and ocean fluxes by subtracting FFCO2. Thus, errors in FFCO2 can propagate into the final inferred flux estimates. Gridded emissions are often based on disaggregation of emissions estimated at national or regional level. Although national and regional total FFCO2 are well known, gridded emission fields are subject to additional uncertainties due to the emission disaggregation. Assessing such uncertainties is often challenging because of the lack of physical measurements for evaluation. We first review difficulties in assessing uncertainties associated with gridded FFCO2 emission data and present several approaches for evaluation of such uncertainties at multiple scales. Given known limitations, inter-emission data differences are often used as a proxy for the uncertainty. The popular approach allows us to characterize differences in emissions, but does not allow us to fully quantify emission disaggregation biases. Our work aims to vicariously evaluate FFCO2 emission data using atmospheric models and measurements. We show a global simulation experiment where uncertainty estimates are propagated as an atmospheric tracer (uncertainty tracer) alongside CO2 in NASA's GEOS model and discuss implications of FFCO2 uncertainties in the context of flux inversions. We also demonstrate the use of high resolution urban CO2 simulations as a tool for objectively evaluating FFCO2 data over intense emission regions. Though this study focuses on FFCO2 emission data, the outcome of this study could also help improve the knowledge of similar gridded emissions data for non-CO2 compounds that share emission sectors.

Field emission study of carbon nanostructures

NASA Astrophysics Data System (ADS)

Zhao, Xin

Recently, carbon nanosheets (CNS), a novel nanostructure, were developed in our laboratory as a field emission source for high emission current. To characterize, understand and improve the field emission properties of CNS, a ultra-high vacuum surface analysis system was customized to conduct relevant experimental research in four distinct areas. The system includes Auger electron spectroscopy (AES), field emission energy spectroscopy (FEES), field emission I-V testing, and thermal desorption spectroscopy (TDS). Firstly, commercial Mo single tips were studied to calibrate the customized system. AES and FEES experiments indicate that a pyramidal nanotip of Ca and O elements formed on the Mo tip surface by field induced surface diffusion. Secondly, field emission I-V testing on CNS indicates that the field emission properties of pristine nanosheets are impacted by adsorbates. For instance, in pristine samples, field emission sources can be built up instantaneously and be characterized by prominent noise levels and significant current variations. However, when CNS are processed via conditioning (run at high current), their emission properties are greatly improved and stabilized. Furthermore, only H2 desorbed from the conditioned CNS, which indicates that only H adsorbates affect emission. Thirdly, the TDS study on nanosheets revealed that the predominant locations of H residing in CNS are sp2 hybridized C on surface and bulk. Fourthly, a fabricating process was developed to coat low work function ZrC on nanosheets for field emission enhancement. The carbide triple-peak in the AES spectra indicated that Zr carbide formed, but oxygen was not completely removed. The Zr(CxOy) coating was dispersed as nanobeads on the CNS surface. Although the work function was reduced, the coated CNS emission properties were not improved due to an increased beta factor. Further analysis suggest that for low emission current (<1 uA), the H adsorbates affect emission by altering the work function. In high emission current (>10 uA), thermal, ionic or electronic transition effects may occur, which differently affect the field emission process.

The true cost of greenhouse gas emissions: analysis of 1,000 global companies.

PubMed

Ishinabe, Nagisa; Fujii, Hidemichi; Managi, Shunsuke

2013-01-01

This study elucidated the shadow price of greenhouse gas (GHG) emissions for 1,024 international companies worldwide that were surveyed from 15 industries in 37 major countries. Our results indicate that the shadow price of GHG at the firm level is much higher than indicated in previous studies. The higher shadow price was found in this study as a result of the use of Scope 3 GHG emissions data. The results of this research indicate that a firm would carry a high cost of GHG emissions if Scope 3 GHG emissions were the focus of the discussion of corporate social responsibility. In addition, such shadow prices were determined to differ substantially among countries, among sectors, and within sectors. Although a number of studies have calculated the shadow price of GHG emissions, these studies have employed country-level or industry-level data or a small sample of firm-level data in one country. This new data from a worldwide firm analysis of the shadow price of GHG emissions can play an important role in developing climate policy and promoting sustainable development.

The True Cost of Greenhouse Gas Emissions: Analysis of 1,000 Global Companies

PubMed Central

Ishinabe, Nagisa; Fujii, Hidemichi; Managi, Shunsuke

2013-01-01

This study elucidated the shadow price of greenhouse gas (GHG) emissions for 1,024 international companies worldwide that were surveyed from 15 industries in 37 major countries. Our results indicate that the shadow price of GHG at the firm level is much higher than indicated in previous studies. The higher shadow price was found in this study as a result of the use of Scope 3 GHG emissions data. The results of this research indicate that a firm would carry a high cost of GHG emissions if Scope 3 GHG emissions were the focus of the discussion of corporate social responsibility. In addition, such shadow prices were determined to differ substantially among countries, among sectors, and within sectors. Although a number of studies have calculated the shadow price of GHG emissions, these studies have employed country-level or industry-level data or a small sample of firm-level data in one country. This new data from a worldwide firm analysis of the shadow price of GHG emissions can play an important role in developing climate policy and promoting sustainable development. PMID:24265710

Comparisons of MOVES Light-duty Gasoline NOx Emission Rates with Real-world Measurements

NASA Astrophysics Data System (ADS)

Choi, D.; Sonntag, D.; Warila, J.

2017-12-01

Recent studies have shown differences between air quality model estimates and monitored values for nitrogen oxides. Several studies have suggested that the discrepancy between monitored and modeled values is due to an overestimation of NOx from mobile sources in EPA's emission inventory, particularly for light-duty gasoline vehicles. EPA's MOtor Vehicle Emission Simulator (MOVES) is an emission modeling system that estimates emissions for cars, trucks and other mobile sources at the national, county, and project level for criteria pollutants, greenhouse gases, and air toxics. Studies that directly measure vehicle emissions provide useful data for evaluating MOVES when the measurement conditions are properly accounted for in modeling. In this presentation, we show comparisons of MOVES2014 to thousands of real-world NOx emissions measurements from individual light-duty gasoline vehicles. The comparison studies include in-use vehicle emissions tests conducted on chassis dynamometer tests in support of Denver, Colorado's Vehicle Inspection & Maintenance Program and remote sensing data collected using road-side instruments in multiple locations and calendar years in the United States. In addition, we conduct comparisons of MOVES predictions to fleet-wide emissions measured from tunnels. We also present details on the methodology used to conduct the MOVES model runs in comparing to the independent data.

Jarosite in the Shergottite Que 94201

NASA Technical Reports Server (NTRS)

Ross, D. K.; Ito, M.; Rao, M. N.; Hervig, R.; Williams, L. B.; Nyquist, Laurence E.; Peslier, A.

2010-01-01

Veins of the hydroxylated, potassium ferric sulfate mineral jarosite - KFe3(SO4)2(OH)6 - have been identified in the martian meteorite Queen Alexandra Range (QUE) 94201. Iron potassium sulfate had been reported in QUE 94201 by Wentworth and Gooding. Jarosite has been reported in other Martian meteorites - Roberts Massif (RBT) 04262, Miller Range (MIL) 03346, and Yamato 000593 - and it has been identified on the Martian surface by Moessbauer spectroscopy. Given the presence of jarosite on Mars, and the burgeoning interest in water-rock interactions on Mars, the question arises whether jarosite in Martian meteorites is formed by aqueous alteration on Mars, or in Antarctica. Hydrogen isotopes are potentially sensitive indicators of the site of formation or last equilibration of hydrous alteration minerals, because of the large difference between D/H ratio of the Martian atmosphere (and also presumably the cryosphere) and terrestrial hydrogen. The Martian atmospheric delta D(sub SMOW) ratio is approximately +4200%o, igneous minerals with substantial hydrogen (phosphates) have high D, +2000%o to +4700%o versus terrestrial waters with approximately 480%o to +130%o. The crystal chemistry and structure of jarosite are reviewed in Papi ke et al. Here we report hydrogen isotopes measured in jarosite in QUE 94201 by ion microprobe, and also report on the major element composition of jarosite measured by electron microprobe.

Relaxation dynamics of light-induced photon emission by mammalian cells and nuclei

NASA Astrophysics Data System (ADS)

Van Wijk, R.; Van Aken, J. M.; Laerdal, H. E.; Souren, J. E. M.

1995-12-01

Photon emission from mammalian cells has been the subject of study for many years. Throughout the history of this field of research the question of a functional biological role of the low intensity emission has been repeatedly raised. The discussion concerns the possible participation of biophotons in intra- and intercellular communication. In this paper we consider the significance of the studies on light-induced photon emission of isolated mammalian cells. Furthermore we report on the source of this light-induced photon emission.

Methane emissions from a landfill in north-east India: Performance of various landfill gas emission models.

PubMed

Gollapalli, Muralidhar; Kota, Sri Harsha

2018-03-01

Rapid urbanization and economic growth has led to significant increase in municipal solid waste generation in India during the last few decades and its management has become a major issue because of poor waste management practices. Solid waste generated is deposited into open dumping sites with hardly any segregation and processing. Carbon dioxide (CO 2 ), methane (CH 4 ) and nitrous oxide (N 2 O) are the major greenhouse gases that are released from the landfill sites due to the biodegradation of organic matter. In this present study, CH 4 and CO 2 emissions from a landfill in north-east India are estimated using a flux chamber during September, 2015 to August, 2016. The average emission rates of CH 4 and CO 2 are 68 and 92 mg/min/m 2 , respectively. The emissions are highest in the summer whilst being lowest in winter. The diurnal variation of emissions indicated that the emissions follow a trend similar to temperature in all the seasons. Correlation coefficients of CH 4 and temperature in summer, monsoon and winter are 0.99, 0.87 and 0.97, respectively. The measured CH 4 in this study is in the range of other studies around the world. Modified Triangular Method (MTM), IPCC model and the USEPA Landfill gas emissions model (LandGEM) were used to predict the CH 4 emissions during the study year. The consequent simulation results indicate that the MTM, LandGEM-Clean Air Act, LandGEM-Inventory and IPCC models predict 1.9, 3.3, 1.6 and 1.4 times of the measured CH 4 emission flux in this study. Assuming that this higher prediction of CH 4 levels observed in this study holds well for other landfills in this region, a new CH 4 emission inventory (Units: Tonnes/year), with a resolution of 0.1 0  × 0.1 0 has been developed. This study stresses the importance of biodegradable composition of waste and meteorology, and also points out the drawbacks of the widely used landfill emission models. Copyright © 2017 Elsevier Ltd. All rights reserved.

Attributing land-use change carbon emissions to exported biomass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saikku, Laura, E-mail: laura.saikku@helsinki.fi; Soimakallio, Sampo, E-mail: sampo.soimakallio@vtt.fi; Pingoud, Kim, E-mail: kim.pingoud@vtt.fi

2012-11-15

In this study, a simple, transparent and robust method is developed in which land-use change (LUC) emissions are retrospectively attributed to exported biomass products based on the agricultural area occupied for the production. LUC emissions account for approximately one-fifth of current greenhouse gas emissions. Increasing agricultural exports are becoming an important driver of deforestation. Brazil and Indonesia are used as case studies due to their significant deforestation in recent years. According to our study, in 2007, approximately 32% and 15% of the total agricultural land harvested and LUC emissions in Brazil and Indonesia respectively were due to exports. The mostmore » important exported single items with regard to deforestation were palm oil for Indonesia and bovine meat for Brazil. To reduce greenhouse gas (GHG) emissions effectively worldwide, leakage of emissions should be avoided. This can be done, for example, by attributing embodied LUC emissions to exported biomass products. With the approach developed in this study, controversial attribution between direct and indirect LUC and amortization of emissions over the product life cycle can be overcome, as the method operates on an average basis and annual level. The approach could be considered in the context of the UNFCCC climate policy instead of, or alongside with, other instruments aimed at reducing deforestation. However, the quality of the data should be improved and some methodological issues, such as the allocation procedure in multiproduct systems and the possible dilution effect through third parties not committed to emission reduction targets, should be considered. - Highlights: Black-Right-Pointing-Pointer CO{sub 2} emissions from land use changes are highly important. Black-Right-Pointing-Pointer Attribution of land use changes for products is difficult. Black-Right-Pointing-Pointer Simple and robust method is developed to attribute land use change emissions.« less

Emission inventory of primary air pollutants in 2010 from industrial processes in Turkey.

PubMed

Alyuz, Ummugulsum; Alp, Kadir

2014-08-01

The broad objective of this study was to develop CO2, PM, SOx, CO, NOx, VOC, NH3 and N2O emission inventory of organic and inorganic chemicals, mineral products, metallurgical, petroleum refining, wood products, food industries of Turkey for 2010 for both co]ntrolled and uncontrolled conditions. In this study, industries were investigated in 7 main categories and 53 sub-sectors and a representative number of pollutants per sub-sector were considered. Each industry was evaluated in terms of emitted emissions only from industrial processes, and fuel combustion activities were excluded (except cement industry). The study employed an approach designed in four stages; identification of key categories; activity data & emission factor search; emission factor analyzing; calculation of emissions. Emission factor analyzing required aggregate and firm analysis of sectors and sub-sectors and deeper insights into underlying specific production methods used in the industry to decide on the most representative emission factor. Industry specific abatement technologies were considered by using open-source documents and industry specific reports. Regarding results of this study, mineral industry and iron & steel industry were determined as important contributors of industrial emissions in Turkey in 2010. Respectively, organic chemicals, petroleum refining, and pulp & paper industries had serious contributions to Turkey's air pollutant emission inventory from industrial processes. The results showed that calculated CO2 emissions for year 2010 was 55,124,263 t, also other emissions were 48,853 t PM, 24,533 t SOx, 79,943 t NOx, 31,908 t VOC, 454 t NH3 and 2264 t N2O under controlled conditions. Copyright © 2014 Elsevier B.V. All rights reserved.

Weekly agricultural emissions and ambient concentrations of ammonia: Validation of an emission inventory

NASA Astrophysics Data System (ADS)

Bittman, Shabtai; Jones, Keith; Vingarzan, Roxanne; Hunt, Derek E.; Sheppard, Steve C.; Tait, John; So, Rita; Zhao, Johanna

2015-07-01

Weekly inventories for emissions of agricultural ammonia were calculated for 139 4 × 4 km grid cells over 52 weeks in the intensely farmed Lower Fraser Valley, BC. The grid cells were located both inside and outside an area that had been depopulated of poultry due to an outbreak of Avian Influenza prior to the start of the study. During the study period, ambient ammonia concentrations were measured hourly at two locations outside the cull area and one location inside the cull area. Large emission differences between grid cells and differences in temporal variation between cells were related to farming practices and meteorological factors such as temperature and rainfall. Weekly average ambient concentrations at the three sampling locations were significantly correlated with estimates of weekly emissions for many of the grid cells in the study area. Inside the cull area, ambient concentrations during the cull (week 1) were 37% of the concentrations after the cull (week 52), while outside the cull there was almost no difference between week 1 and week 52, suggesting that in normal (non-cull) conditions, about 60% of the ambient ammonia was due to poultry farms. Estimated emissions in weeks 1 and 52 for grid cells affected by the cull indicated that over 90% of the emissions came from poultry. The discrepancy in difference between week 1 and 52 for emissions and ambient concentrations could be due to atmospheric factors like transport, atmospheric reactions, dispersion or deposition; to errors in the inventory including farming data, emission factors; and omission of some non-poultry emission sources. Overall the study supports the ammonia emission inventory estimates. Detailed emission data helps in modeling ammonia in the atmosphere and is useful for developing abatement policy.

PM, NOx and butane emissions from on-road vehicle fleets in Hong Kong and their implications on emission control policy

NASA Astrophysics Data System (ADS)

Ning, Zhi; Wubulihairen, Maimaitireyimu; Yang, Fenhuan

2012-12-01

Vehicular emissions are the major sources of air pollution in urban areas. For metropolitan cities with large population working and living in environments with direct traffic impact, emission control is of great significance to protect public health. Implementation of more stringent emission standards, retrofitting fleet with emission control devices and switching to clearer fuel has been commonly practiced in different cities including Hong Kong. The present study employed a new plume chasing method for effective and quick evaluation of on-road fleet emission factors of particulate matter (PM), nitrogen oxides (NOx), and butane from heavy duty diesel trucks, diesel buses and liquefied petroleum gas (LPG) vehicles. The results showed distinct profiles of the emissions from different fleets with excessive butane emissions from LPG fleet and contrasting PM and NOx emissions from diesel trucks and buses fleets. A cross comparison was also made with emission data from other cities and from historic local studies. The implications of the observed difference on the effectiveness of emission control measures and policy are discussed with recommendations of direction for future research and policy making.

Speed Profiles for Improvement of Maritime Emission Estimation.

PubMed

Yau, Pui Shan; Lee, Shun-Cheng; Ho, Kin Fai

2012-12-01

Maritime emissions play an important role in anthropogenic emissions, particularly for cities with busy ports such as Hong Kong. Ship emissions are strongly dependent on vessel speed, and thus accurate vessel speed is essential for maritime emission studies. In this study, we determined minute-by-minute high-resolution speed profiles of container ships on four major routes in Hong Kong waters using Automatic Identification System (AIS). The activity-based ship emissions of NO(x), CO, HC, CO(2), SO(2), and PM(10) were estimated using derived vessel speed profiles, and results were compared with those using the speed limits of control zones. Estimation using speed limits resulted in up to twofold overestimation of ship emissions. Compared with emissions estimated using the speed limits of control zones, emissions estimated using vessel speed profiles could provide results with up to 88% higher accuracy. Uncertainty analysis and sensitivity analysis of the model demonstrated the significance of improvement of vessel speed resolution. From spatial analysis, it is revealed that SO(2) and PM(10) emissions during maneuvering within 1 nautical mile from port were the highest. They contributed 7%-22% of SO(2) emissions and 8%-17% of PM(10) emissions of the entire voyage in Hong Kong.

Extreme optical Fe II emission in luminous IRAS active galactic nuclei

NASA Technical Reports Server (NTRS)

Lipari, Sebastian; Terlevich, Roberto; Macchetto, F.

1993-01-01

Results of a program of studies and observations of strong optical Fe II emission in luminous and ultraluminous IRAS AGN are presented. New spectroscopic observations and studies of three known ultraluminous IRAS AGN with extreme optical Fe II emission, the discovery that PHL 1092 is a new ultraluminous IRAS AGN, and the detection of two new AGN with strongly variable flux in the optical Fe II emission lines are reported. These results are used to test the correlations between the Fe II emission and properties at other wavelengths such as the L(IR) and the radio emission. IR AGN with extreme Fe II emission are found to belong to a very important group of AGN, whose properties provide insight into the origin of the extreme Fe II emission and into the relation between the starburst and AGN phenomena.

Recent volcanic activity on Venus - Evidence from radiothermal emissivity measurements

NASA Technical Reports Server (NTRS)

Robinson, Cordula A.; Wood, John A.

1993-01-01

Radiothermal emissivity measurements are analyzed in order to study large volcanic constructs on Venus and to correlate details of the reflectivity/emissivity patterns with geological landforms and stratigraphy visible in corresponding SAR images. There appears to be a correlation between locations on Venus where high emissivity at high altitudes and low emissivity at low altitudes are observed. These phenomena are attributed here to relatively recent volcanic activity: the former to summit eruptions that have not had time to weather to the low-emissivity state, the latter to continuing emission of volcanic gases from neighboring small plains volcanoes. The pattern of reflectivity and emissivity on Maat Mons is examined in the light of these findings. It is concluded that Maat Mons has undergone the most recent episode of volcanic activity of all the volcanoes studied here.

Understanding how seasonality and shifts in species composition impact emission estimates in semi-arid ecosystems

NASA Astrophysics Data System (ADS)

Sparks, A. M.; Yokelson, R. J.; Smith, A. M.; Marshall, J. D.; Tinkham, W.

2013-12-01

The importance of wildland fire as a source of trace gas emissions to the atmosphere has been demonstrated in the scientific literature and through numerous NASA funded campaigns to further understand the drivers and impacts of these emissions (e.g., SAFARI 1992, SAFARI 2000, TRACE A, etc). Most studies quantify emissions using remotely sensed data through multiplying the area burned, the quantity of fuel combusted, and the emission factors of a given gas species (EFX, grams of gas, X, emitted per kilogram of fuel consumed). The latter is known to exhibit considerable uncertainty and indeed a prior study as part of NASA's SAFARI 2000 campaign highlighted a seasonal dependence of carbonaceous gas species emissions. In this study, rangeland grass and shrub species were collected periodically from northern Great Basin shrub-steppe ecosystems during the typical burn season and burned in a small-scale laboratory setup where major carbonaceous and nitrogenous emission species were monitored and measured. Preliminary results indicate that emission factors of several major gas species, including carbon monoxide and nitrogen oxides, vary considerably over the course of a season. Large differences in emission apportionment between the rangeland species also suggests that shifting vegetation composition (via replacement of native with invasive species) can have a significant influence on emissions from semi-arid ecosystems. Further development of this data could lead to an enhanced understanding of how emission factors vary seasonally and how total emissions change with major vegetation shifts in other ecosystems.

Ammonia emissions in Europe, part II: How ammonia emission abatement strategies affect secondary aerosols

NASA Astrophysics Data System (ADS)

Backes, Anna M.; Aulinger, Armin; Bieser, Johannes; Matthias, Volker; Quante, Markus

2016-02-01

In central Europe, ammonium sulphate and ammonium nitrate make up a large fraction of fine particles which pose a threat to human health. Most studies on air pollution through particulate matter investigate the influence of emission reductions of sulphur- and nitrogen oxides on aerosol concentration. Here, we focus on the influence of ammonia (NH3) emissions. Emission scenarios have been created on the basis of the improved ammonia emission parameterization implemented in the SMOKE for Europe and CMAQ model systems described in part I of this study. This includes emissions based on future European legislation (the National Emission Ceilings) as well as a dynamic evaluation of the influence of different agricultural sectors (e.g. animal husbandry) on particle formation. The study compares the concentrations of NH3, NH4+, NO3 -, sulphur compounds and the total concentration of particles in winter and summer for a political-, technical- and behavioural scenario. It was found that a reduction of ammonia emissions by 50% lead to a 24% reduction of the total PM2.5 concentrations in northwest Europe. The observed reduction was mainly driven by reduced formation of ammonium nitrate. Moreover, emission reductions during winter had a larger impact than during the rest of the year. This leads to the conclusion that a reduction of the ammonia emissions from the agricultural sector related to animal husbandry could be more efficient than the reduction from other sectors due to its larger share in winter ammonia emissions.

A spatially resolved fuel-based inventory of Utah and Colorado oil and natural gas emissions

NASA Astrophysics Data System (ADS)

Gorchov Negron, A.; McDonald, B. C.; De Gouw, J. A.; Frost, G. J.

2015-12-01

A fuel-based approach is presented for estimating emissions from US oil and natural gas production that utilizes state-level fuel surveys of oil and gas engine activity, well-level production data, and emission factors for oil and gas equipment. Emissions of carbon dioxide (CO2) and nitrogen oxides (NOx) are mapped on a 4 km x 4 km horizontal grid for 2013-14 in Utah and Colorado. Emission sources include combustion from exploration (e.g., drilling), production (e.g., heaters, dehydrators, and compressor engines), and natural gas processing plants, which comprise a large fraction of the local combustion activity in oil and gas basins. Fuel-based emission factors of NOx are from the U.S. Environmental Protection Agency, and applied to spatially-resolved maps of CO2 emissions. Preliminary NOx emissions from this study are estimated for the Uintah Basin, Utah, to be ~5300 metric tons of NO2-equivalent in 2013. Our result compares well with an observations-based top-down emissions estimate of NOx derived from a previous study, ~4200 metric tons of NO2-equivalent. By contrast, the 2011 National Emissions Inventory estimates oil and gas emissions of NOx to be ~3 times higher than our study in the Uintah Basin. We intend to expand our fuel-based approach to map combustion-related emissions in other U.S. oil and natural gas basins and compare with additional observational datasets.

Emission factors of air toxics from semiconductor manufacturing in Korea.

PubMed

Eom, Yun-Sung; Hong, Ji-Hyung; Lee, Suk-Jo; Lee, Eun-Jung; Cha, Jun-Seok; Lee, Dae-Gyun; Bang, Sun-Ae

2006-11-01

The development of local, accurate emission factors is very important for the estimation of reliable national emissions and air quality management. For that, this study is performed for pollutants released to the atmosphere with source-specific emission tests from the semiconductor manufacturing industry. The semiconductor manufacturing industry is one of the major sources of air toxics or hazardous air pollutants (HAPs); thus, understanding the emission characteristics of the emission source is a very important factor in the development of a control strategy. However, in Korea, there is a general lack of information available on air emissions from the semiconductor industry. The major emission sources of air toxics examined from the semiconductor manufacturing industry were wet chemical stations, coating applications, gaseous operations, photolithography, and miscellaneous devices in the wafer fabrication and semiconductor packaging processes. In this study, analyses of emission characteristics, and the estimations of emission data and factors for air toxics, such as acids, bases, heavy metals, and volatile organic compounds from the semiconductor manufacturing process have been performed. The concentration of hydrogen chloride from the packaging process was the highest among all of the processes. In addition, the emission factor of total volatile organic compounds (TVOCs) for the packaging process was higher than that of the wafer fabrication process. Emission factors estimated in this study were compared with those of Taiwan for evaluation, and they were found to be of similar level in the case of TVOCs and fluorine compounds.

NREL Study Predicts Fuel and Emissions Impact of Automated Mobility

Science.gov Websites

District | News | NREL Study Predicts Fuel and Emissions Impact of Automated Mobility District NREL Study Predicts Fuel and Emissions Impact of Automated Mobility District January 21, 2016 With NREL study shows that a campus-sized -- ranging from four to 10 square miles -- automated mobility

The Impact of a Potential Shale Gas Development in Germany and the United Kingdom on Pollutant and Greenhouse Gas Emissions

NASA Astrophysics Data System (ADS)

Weger, L.; Cremonese, L.; Bartels, M. P.; Butler, T. M.

2016-12-01

Several European countries with domestic shale gas reserves are considering extracting this natural gas resource to complement their energy transition agenda. Natural gas, which produces lower CO2 emissions upon combustion compared to coal or oil, has the potential to serve as a bridge in the transition from fossil fuels to renewables. However, the generation of shale gas leads to emissions of CH4 and pollutants such as PM, NOx and VOCs, which in turn impact climate as well as local and regional air quality. In this study, we explore the impact of a potential shale gas development in Europe, specifically in Germany and the United Kingdom, on emissions of greenhouse gases and pollutants. In order to investigate the effect on emissions, we first estimate a range of wells drilled per year and production volume for the two countries under examination based on available geological information and on regional infrastructural and economic limitations. Subsequently we assign activity data and emissions factors to the well development, gas production and processing stages of shale gas generation to enable emissions quantification. We then define emissions scenarios to explore different storylines of potential shale gas development, including low emissions (high level of regulation), high emissions (low level of regulation) and middle emissions scenarios, which influence fleet make-up, emission factor and activity data choices for emissions quantification. The aim of this work is to highlight important variables and their ranges, to promote discussion and communication of potential impacts, and to construct possible visions for a future shale gas development in the two study countries. In a follow-up study, the impact of pollutant emissions from these scenarios on air quality will be explored using the Weather Research and Forecasting model with chemistry (WRF-Chem) model.

An integrated analytical framework for quantifying the LCOE of waste-to-energy facilities for a range of greenhouse gas emissions policy and technical factors.

PubMed

Townsend, Aaron K; Webber, Michael E

2012-07-01

This study presents a novel integrated method for considering the economics of waste-to-energy (WTE) facilities with priced greenhouse gas (GHG) emissions based upon technical and economic characteristics of the WTE facility, MSW stream, landfill alternative, and GHG emissions policy. The study demonstrates use of the formulation for six different policy scenarios and explores sensitivity of the results to ranges of certain technical parameters as found in existing literature. The study shows that details of the GHG emissions regulations have large impact on the levelized cost of energy (LCOE) of WTE and that GHG regulations can either increase or decrease the LCOE of WTE depending on policy choices regarding biogenic fractions from combusted waste and emissions from landfills. Important policy considerations are the fraction of the carbon emissions that are priced (i.e. all emissions versus only non-biogenic emissions), whether emissions credits are allowed due to reducing fugitive landfill gas emissions, whether biogenic carbon sequestration in landfills is credited against landfill emissions, and the effectiveness of the landfill gas recovery system where waste would otherwise have been buried. The default landfill gas recovery system effectiveness assumed by much of the industry yields GHG offsets that are very close to the direct non-biogenic GHG emissions from a WTE facility, meaning that small changes in the recovery effectiveness cause relatively larger changes in the emissions factor of the WTE facility. Finally, the economics of WTE are dependent on the MSW stream composition, with paper and wood being advantageous, metal and glass being disadvantageous, and plastics, food, and yard waste being either advantageous or disadvantageous depending upon the avoided tipping fee and the GHG emissions price. Copyright © 2012 Elsevier Ltd. All rights reserved.

Discrepancies and Uncertainties in Bottom-up Gridded Inventories of Livestock Methane Emissions for the Contiguous United States

NASA Astrophysics Data System (ADS)

Randles, C. A.; Hristov, A. N.; Harper, M.; Meinen, R.; Day, R.; Lopes, J.; Ott, T.; Venkatesh, A.

2017-12-01

In this analysis we used a spatially-explicit, bottom-up approach, based on animal inventories, feed intake, and feed intake-based emission factors to estimate county-level enteric (cattle) and manure (cattle, swine, and poultry) livestock methane emissions for the contiguous United States. Combined enteric and manure emissions were highest for counties in California's Central Valley. Overall, this analysis yielded total livestock methane emissions (8,916 Gg/yr; lower and upper bounds of 6,423 and 11,840 Gg/yr, respectively) for 2012 that are comparable to the current USEPA estimates for 2012 (9,295 Gg/yr) and to estimates from the global gridded Emission Database for Global Atmospheric Research (EDGAR) inventory (8,728 Gg/yr), used previously in a number of top-down studies. However, the spatial distribution of emissions developed in this analysis differed significantly from that of EDGAR. As an example, methane emissions from livestock in Texas and California (highest contributors to the national total) in this study were 36% lesser and 100% greater, respectively, than estimates by EDGAR. Thespatial distribution of emissions in gridded inventories (e.g., EDGAR) likely strongly impacts the conclusions of top-down approaches that use them, especially in the source attribution of resulting (posterior) emissions, and hence conclusions from such studies should be interpreted with caution.

Cost of lower NO x emissions: Increased CO 2 emissions from heavy-duty diesel engines

NASA Astrophysics Data System (ADS)

Krishnamurthy, Mohan; Carder, Daniel K.; Thompson, Gregory; Gautam, Mridul

This paper highlights the effect of emissions regulations on in-use emissions from heavy-duty vehicles powered by different model year engines. More importantly, fuel economy data for pre- and post-consent decree engines are compared. The objective of this study was to determine the changes in brake-specific emissions of NO x as a result of emission regulations, and to highlight the effect these have had on brake-specific CO 2 emission; hence, fuel consumption. For this study, in-use, on-road emission measurements were collected. Test vehicles were instrumented with a portable on-board tailpipe emissions measurement system, WVU's Mobile Emissions Measurement System, and were tested on specific routes, which included a mix of highway and city driving patterns, in order to collect engine operating conditions, vehicle speed, and in-use emission rates of CO 2 and NO x. Comparison of on-road in-use emissions data suggests NO x reductions as high as 80% and 45% compared to the US Federal Test Procedure and Not-to-Exceed standards for model year 1995-2002. However, the results indicate that the fuel consumption; hence, CO 2 emissions increased by approximately 10% over the same period, when the engines were operating in the Not-to-Exceed region.

Evaluation of diesel fleet emissions and control policies from plume chasing measurements of on-road vehicles

NASA Astrophysics Data System (ADS)

Lau, Chui Fong; Rakowska, Agata; Townsend, Thomas; Brimblecombe, Peter; Chan, Tat Leung; Yam, Yat Shing; Močnik, Griša; Ning, Zhi

2015-12-01

Vehicle emissions are an important source of urban air pollution. Diesel fuelled vehicles, although constituting a relatively small fraction of fleet population in many cities, are significant contributors to the emission inventory due to their often long mileage for goods and public transport. Recent classification of diesel exhaust as carcinogenic by the World Health Organization also raises attention to more stringent control of diesel emissions to protect public health. Although various mandatory and voluntary based emission control measures have been implemented in Hong Kong, there have been few investigations to evaluate if the fleet emission characteristics have met desired emission reduction objectives and if adoption of an Inspection/Maintenance (I/M) programme has been effective in achieving these objectives. The limitations are partially due to the lack of cost-effective approaches for the large scale characterisation of fleet based emissions to assess the effectiveness of control measures and policy. This study has used a plume chasing method to collect a large amount of on-road vehicle emission data of Hong Kong highways and a detailed analysis was carried out to provide a quantitative evaluation of the emission characteristics in terms of the role of high and super-emitters in total emission reduction, impact of after-treatment on the multi-pollutants reduction strategy and the trend of NO2 emissions with newer emission standards. The study revealed that not all the high-emitters are from those vehicles of older Euro emission standards. Meanwhile, there is clear evidence that high-emitters for one pollutant may not be a high-emitter for another pollutant. Multi-pollutant control strategy needs to be considered in the enactment of the emission control policy which requires more comprehensive retrofitting technological solutions and matching I/M programme to ensure the proper maintenance of fleets. The plume chasing approach used in this study also shows to be a useful approach for assessing city wide vehicle emission characteristics.

Modeling spatial patterns of link-based PM2.5 emissions and subsequent human exposure in a large canadian metropolitan area

NASA Astrophysics Data System (ADS)

Requia, Weeberb J.; Dalumpines, Ron; Adams, Matthew D.; Arain, Altaf; Ferguson, Mark; Koutrakis, Petros

2017-06-01

Understanding the relationship between mobile source emissions and subsequent human exposure is crucial for emissions control. Determining this relationship over space is fundamental to improve the accuracy and precision of public policies. In this study, we evaluated the spatial patterns of link-based PM2.5 emissions and subsequent human exposure in a large Canadian metropolitan area - the Greater Toronto and Hamilton Area (GTHA). This study was performed in three stages. First, we estimated vehicle emissions using transportation models and emission simulators. Then we evaluated human exposure to PM2.5 emissions using the Intake fraction (iF) approach. Finally, we applied geostatistical methods to assess spatial patterns of vehicle emissions and subsequent human exposure based on three prospective goals: i) classification of emissions (Global Moran's I test), ii) level of emission exposure (Getis-Ord General G test), and; iii) location of emissions (Anselin Local Moran's I). Our results showed that passenger vehicles accounted for the highest total amount of PM2.5 emissions, representing 57% emissions from all vehicles. Examining only the emissions from passenger vehicles, on average, each person in the GTHA inhales 2.58 × 10-3 ppm per day. Accounting the emissions from buses and trucks, on average each person inhales 0.12 × 10-3 and 1.91 × 10-3 ppm per day, respectively. For both PM2.5 emissions and human exposure using iF approach, our analysis showed Moran's Index greater than 0 for all vehicle categories, suggesting the presence of significant clusters (p-value <0.01) in the region. Our study indicates that air pollution control policy must be developed for the whole region, because of the spatial distribution of housing and businesses centers and inter-connectivity of transportation networks across the region, where a policy cannot simply be based on a municipal or other boundaries.

Rocket and spacecraft studies of ultraviolet emissions from astrophysical targets

NASA Technical Reports Server (NTRS)

Fastie, W. G.; Moos, H. W.; Feldman, P. D.; Henry, R. C.

1975-01-01

Rocket and spacecraft far-UV spectral measurements of several astrophysical targets are reviewed. These include observations of Ly-alpha emissions from Arcturus, Apollo-17 far-UV spectrometry of eta UMa and five other stars, Apollo-17 observations of the lunar atmosphere and the diffuse UV background, and far-UV spectral studies of Venus, Jupiter, and Comet Kohoutek. The Arcturus observations indicated a chromosphere with neutral atomic-hydrogen and atomic-oxygen emissions as well as a very weak atomic-carbon line. The planetary studies revealed O I and C I emissions in the Venusian spectrum as well as large Ly-alpha emissions and possible molecular-hydrogen emissions in that of Jupiter. The lunar observations demonstrated that solar protons do not produce an atomic-hydrogen atmosphere on the moon.

Understanding how Seasonality and Shifts in Species Composition Impact Emission Estimates in Semi-Arid Ecosystems

NASA Astrophysics Data System (ADS)

Sparks, A.

2012-12-01

The importance of wildland fire as a source of trace gas emissions to the atmosphere has been demonstrated in the scientific literature and through numerous NASA funded campaigns to further understand the drivers and impacts of these emissions (e.g., SAFARI 1992, SAFARI 2000, TRACE A, etc). Most studies quantify the emissions using remotely sensed data through multiplying the area burned, the quantity of fuel combusted, and the emission factors of a given gas species (EFX, grams of gas, X, emitted per kilogram of fuel consumed). The latter is known to exhibit considerable uncertainty and indeed a prior study as part of NASA's SAFARI 2000 campaign highlighted a seasonal dependence of carbonaceous gas species emissions. Building off these past studies, the focus of the proposed research is to assess the influence of both seasonality and shifting vegetation composition (via replacement of native with invasive species), on the emissions of trace gases in semi-arid ecosystems. Emissions data will help lower emission factor uncertainties in sagebrush-steppe ecosystems as well as inform management decisions about the best burning times in a season (in terms of air quality and greenhouse gas production).

Mercury emissions from biomass burning in China.

PubMed

Huang, Xin; Li, Mengmeng; Friedli, Hans R; Song, Yu; Chang, Di; Zhu, Lei

2011-11-01

Biomass burning covers open fires (forest and grassland fires, crop residue burning in fields, etc.) and biofuel combustion (crop residues and wood, etc., used as fuel). As a large agricultural country, China may produce large quantities of mercury emissions from biomass burning. A new mercury emission inventory in China is needed because previous studies reflected outdated biomass burning with coarse resolution. Moreover, these studies often adopted the emission factors (mass of emitted species per mass of biomass burned) measured in North America. In this study, the mercury emissions from biomass burning in China (excluding small islands in the South China Sea) were estimated, using recently measured mercury concentrations in various biomes in China as emission factors. Emissions from crop residues and fuelwood were estimated based on annual reports distributed by provincial government. Emissions from forest and grassland fires were calculated by combining moderate resolution imaging spectroradiometer (MODIS) burned area product with combustion efficiency (ratio of fuel consumption to total available fuels) considering fuel moisture. The average annual emission from biomass burning was 27 (range from 15.1 to 39.9) Mg/year. This inventory has high spatial resolution (1 km) and covers a long period (2000-2007), making it useful for air quality modeling.

Effects of soil temperature, flooding, and organic matter addition on N2O emissions from a soil of Hongze Lake wetland, China.

PubMed

Lu, Yan; Xu, Hongwen

2014-01-01

The objectives of this study were to test the effects of soil temperature, flooding, and raw organic matter input on N2O emissions in a soil sampled at Hongze Lake wetland, Jiangsu Province, China. The treatments studied were-peat soil (I), peat soil under flooding (II), peat soil plus raw organic matter (III), and peat soil under flooding plus organic matter. These four treatments were incubated at 20°C and 35°C. The result showed that temperature increase could enhance N2O emissions rate and cumulative emissions significantly; moreover, the flooded soil with external organic matter inputs showed the lowest cumulative rise in N2O emissions due to temperature increment. Flooding might inhibit soil N2O emissions, and the inhibition was more pronounced after organic matter addition to the original soil. Conversely, organic matter input explained lower cumulative N2O emissions under flooding. Our results suggest that complex interactions between flooding and other environmental factors might appear in soil N2O emissions. Further studies are needed to understand potential synergies or antagonisms between environmental factors that control N2O emissions in wetland soils.

Polychlorinated dibenzo-p-dioxin and dibenzofuran and polychlorinated biphenyl emissions from different smelting stages in secondary copper metallurgy.

PubMed

Hu, Jicheng; Zheng, Minghui; Nie, Zhiqiang; Liu, Wenbin; Liu, Guorui; Zhang, Bing; Xiao, Ke

2013-01-01

Secondary copper production has received much attention for its high emissions of polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/F) reported in previous studies. These studies focused on the estimation of total PCDD/F and polychlorinated biphenyl (PCB) emissions from secondary copper smelters. However, large variations in PCDD/F and PCB emissions reported in these studies were not analyzed and discussed further. In this study, stack gas samples at different smelting stages (feeding-fusion, oxidation and deoxidization) were collected from four plants to investigate variations in PCDD/F and PCB emissions and characteristics during the secondary copper smelting process. The results indicate that PCDD/F emissions occur mainly at the feeding-fusion stage and these emissions contribute to 54-88% of the total emissions from the secondary copper smelting process. The variation in feed material and operating conditions at different smelting stages leads to the variation in PCDD/F emissions during the secondary copper smelting process. The total PCDD/F and PCB discharge (stack gas emission+fly ash discharge) is consistent with the copper scrap content in the raw material in the secondary copper smelters investigated. On a production basis of 1 ton copper, the total PCDD/F and dl-PCB discharge was 102, 24.8 and 5.88 μg TEQ t(-1) for the three plants that contained 100%, 30% and 0% copper scrap in their raw material feed, respectively. Copyright © 2012 Elsevier Ltd. All rights reserved.

Evaluation of the effect of accounting method, IPCC v. LCA, on grass-based and confinement dairy systems' greenhouse gas emissions.

PubMed

O'Brien, D; Shalloo, L; Patton, J; Buckley, F; Grainger, C; Wallace, M

2012-09-01

Life cycle assessment (LCA) and the Intergovernmental Panel on Climate Change (IPCC) guideline methodology, which are the principal greenhouse gas (GHG) quantification methods, were evaluated in this study using a dairy farm GHG model. The model was applied to estimate GHG emissions from two contrasting dairy systems: a seasonal calving pasture-based dairy farm and a total confinement dairy system. Data used to quantify emissions from these systems originated from a research study carried out over a 1-year period in Ireland. The genetic merit of cows modelled was similar for both systems. Total mixed ration was fed in the Confinement system, whereas grazed grass was mainly fed in the grass-based system. GHG emissions from these systems were quantified per unit of product and area. The results of both methods showed that the dairy system that emitted the lowest GHG emissions per unit area did not necessarily emit the lowest GHG emissions possible for a given level of product. Consequently, a recommendation from this study is that GHG emissions be evaluated per unit of product given the growing affluent human population and increasing demand for dairy products. The IPCC and LCA methods ranked dairy systems' GHG emissions differently. For instance, the IPCC method quantified that the Confinement system reduced GHG emissions per unit of product by 8% compared with the grass-based system, but the LCA approach calculated that the Confinement system increased emissions by 16% when off-farm emissions associated with primary dairy production were included. Thus, GHG emissions should be quantified using approaches that quantify the total GHG emissions associated with the production system, so as to determine whether the dairy system was causing emissions displacement. The IPCC and LCA methods were also used in this study to simulate, through a dairy farm GHG model, what effect management changes within both production systems have on GHG emissions. The findings suggest that single changes have a small mitigating effect on GHG emissions (<5%), except for strategies used to control emissions from manure storage in the Confinement system (14% to 24%). However, when several management strategies were combined, GHG emissions per unit of product could be reduced significantly (15% to 30%). The LCA method was identified as the preferred approach to assess the effect of management changes on GHG emissions, but the analysis indicated that further standardisation of the approach is needed given the sensitivity of the approach to allocation decisions regarding milk and meat.

Constraining CO emission estimates using atmospheric observations

NASA Astrophysics Data System (ADS)

Hooghiemstra, P. B.

2012-06-01

We apply a four-dimensional variational (4D-Var) data assimilation system to optimize carbon monoxide (CO) emissions and to reduce the uncertainty of emission estimates from individual sources using the chemistry transport model TM5. In the first study only a limited amount of surface network observations from the National Oceanic and Atmospheric Administration Earth System Research Laboratory (NOAA/ESRL) Global Monitoring Division (GMD) is used to test the 4D-Var system. Uncertainty reduction up to 60% in yearly emissions is observed over well-constrained regions and the inferred emissions compare well with recent studies for 2004. However, since the observations only constrain total CO emissions, the 4D-Var system has difficulties separating anthropogenic and biogenic sources in particular. The inferred emissions are validated with NOAA aircraft data over North America and the agreement is significantly improved from the prior to posterior simulation. Validation with the Measurements Of Pollution In The Troposphere (MOPITT) instrument shows a slight improved agreement over the well-constrained Northern Hemisphere and in the tropics (except for the African continent). However, the model simulation with posterior emissions underestimates MOPITT CO total columns on the remote Southern Hemisphere (SH) by about 10%. This is caused by a reduction in SH CO sources mainly due to surface stations on the high southern latitudes. In the second study, we compare two global inversions to estimate carbon monoxide (CO) emissions for 2004. Either surface flask observations from NOAA or CO total columns from the MOPITT instrument are assimilated in a 4D-Var framework. In the Southern Hemisphere (SH) three important findings are reported. First, due to their different vertical sensitivity, the stations-only inversion increases SH biomass burning emissions by 108 Tg CO/yr more than the MOPITT-only inversion. Conversely, the MOPITT-only inversion results in SH natural emissions (mainly CO from oxidation of NMVOCs) that are 185 Tg CO/yr higher compared to the stations-only inversion. Second, MOPITT-only derived biomass burning emissions are reduced with respect to the prior which is in contrast to previous (inverse) modeling studies. Finally, MOPITT derived total emissions are significantly higher for South America and Africa compared to the stations-only inversion. This is likely due to a positive bias in the MOPITT V4 product. This bias is also apparent from validation with surface stations and ground-truth FTIR columns. In the final study we present the first inverse modeling study to estimate CO emissions constrained by both surface (NOAA) and satellite (MOPITT) observations using a bias correction scheme. This approach leads to the identification of a positive bias of maximum 5 ppb in MOPITT column-averaged CO mixing ratios in the remote Southern Hemisphere (SH). The 4D-Var system is used to estimate CO emissions over South America in the period 2006-2010 and to analyze the interannual variability (IAV) of these emissions. We infer robust, high spatial resolution CO emission estimates that show slightly smaller IAV due to fires compared to the Global Fire Emissions Database (GFED3) prior emissions. Moreover, CO emissions probably associated with pre-harvest burning of sugar cane plantations are underestimated in current inventories by 50-100%.

Reducing Energy Cost and Greenhouse Gas Emission in the Corporate Sector, a Delphi Study

ERIC Educational Resources Information Center

Kramer, Maxim L.

2013-01-01

The study is titled "Reducing energy cost and GreenHouse Gas emission in the corporate sector, A Delphi Study". The study applied the Delphi methodology and focused on the Green IT solutions that can help the modern corporate organizations with less than 1000 employees to decrease their energy costs and GHG emissions. The study presents…

Emissions of carbon tetrachloride from Europe

NASA Astrophysics Data System (ADS)

Graziosi, Francesco; Arduini, Jgor; Bonasoni, Paolo; Furlani, Francesco; Giostra, Umberto; Manning, Alistair J.; McCulloch, Archie; O'Doherty, Simon; Simmonds, Peter G.; Reimann, Stefan; Vollmer, Martin K.; Maione, Michela

2016-10-01

Carbon tetrachloride (CCl4) is a long-lived radiatively active compound with the ability to destroy stratospheric ozone. Due to its inclusion in the Montreal Protocol on Substances that Deplete the Ozone Layer (MP), the last two decades have seen a sharp decrease in its large-scale emissive use with a consequent decline in its atmospheric mole fractions. However, the MP restrictions do not apply to the use of carbon tetrachloride as feedstock for the production of other chemicals, implying the risk of fugitive emissions from the industry sector. The occurrence of such unintended emissions is suggested by a significant discrepancy between global emissions as derived from reported production and feedstock usage (bottom-up emissions), and those based on atmospheric observations (top-down emissions). In order to better constrain the atmospheric budget of carbon tetrachloride, several studies based on a combination of atmospheric observations and inverse modelling have been conducted in recent years in various regions of the world. This study is focused on the European scale and based on long-term high-frequency observations at three European sites, combined with a Bayesian inversion methodology. We estimated that average European emissions for 2006-2014 were 2.2 (± 0.8) Gg yr-1, with an average decreasing trend of 6.9 % per year. Our analysis identified France as the main source of emissions over the whole study period, with an average contribution to total European emissions of approximately 26 %. The inversion was also able to allow the localisation of emission "hot spots" in the domain, with major source areas in southern France, central England (UK) and Benelux (Belgium, the Netherlands, Luxembourg), where most industrial-scale production of basic organic chemicals is located. According to our results, European emissions correspond, on average, to 4.0 % of global emissions for 2006-2012. Together with other regional studies, our results allow a better constraint of the global budget of carbon tetrachloride and a better quantification of the gap between top-down and bottom-up estimates.

Seasonal Variation and Ecosystem Dependence of Emission Factors for Selected Trace Gases and PM2.5 for Southern African Savanna Fires

NASA Technical Reports Server (NTRS)

Korontzi, S.; Ward, D. E.; Susott, R. A.; Yokelson, R. J.; Justice, C. O.; Hobbs, P. V.; Smithwick, E. A. H.; Hao, W. M.

2003-01-01

In this paper we present the first early dry season (early June-early August) emission factor measurements for carbon dioxide (CO2), carbon monoxide (CO), methane (Ca), nonmethane hydrocarbons (NMHC), and particulates with a diameter less than 2.5 microns (pM2.5) for southern African grassland and woodland fires. Seasonal emission factors for grassland fires correlate linearly with the proportion of green grass, used as a surrogate for the fuel moisture content, and are higher for products of incomplete combustion in the early part of the dry season compared with later in the dry season. Models of emission factors for NMHC and PM(sub 2.5) versus modified combustion efficiency (MCE) are statistically different in grassland compared with woodland ecosystems. We compare predictions based on the integration of emissions factors from this study, from the southern African Fire-Atmosphere Research Initiative 1992 (SAFARI-92), and from SAFARI-2000 with those based on the smaller set of ecosystem-specific emission factors to estimate the effects of using regional-average rather than ecosystem-specific emission factors. We also test the validity of using the SAFARI-92 models for emission factors versus MCE to predict the early dry season emission factors measured in this study. The comparison indicates that the largest discrepancies occur at the low end (0.907) and high end (0.972) of MCE values measured in this study. Finally, we combine our models of MCE versus proportion of green grass for grassland fires with emission factors versus MCE for selected oxygenated volatile organic compounds measured in the SAFARI-2000 campaign to derive the first seasonal emission factors for these compounds. The results of this study demonstrate that seasonal variations in savanna fire emissions are important and should be considered in modeling emissions at regional to continental scales.

The activity-based methodology to assess ship emissions - A review.

PubMed

Nunes, R A O; Alvim-Ferraz, M C M; Martins, F G; Sousa, S I V

2017-12-01

Several studies tried to estimate atmospheric emissions with origin in the maritime sector, concluding that it contributed to the global anthropogenic emissions through the emission of pollutants that have a strong impact on hu' health and also on climate change. Thus, this paper aimed to review published studies since 2010 that used activity-based methodology to estimate ship emissions, to provide a summary of the available input data. After exclusions, 26 articles were analysed and the main information were scanned and registered, namely technical information about ships, ships activity and movement information, engines, fuels, load and emission factors. The larger part of studies calculating in-port ship emissions concluded that the majority was emitted during hotelling and most of the authors allocating emissions by ship type concluded that containerships were the main pollutant emitters. To obtain technical information about ships the combined use of data from Lloyd's Register of Shipping database with other sources such as port authority's databases, engine manufactures and ship-owners seemed the best approach. The use of AIS data has been growing in recent years and seems to be the best method to report activities and movements of ships. To predict ship powers the Hollenbach (1998) method which estimates propelling power as a function of instantaneous speed based on total resistance and use of load balancing schemes for multi-engine installations seemed to be the best practices for more accurate ship emission estimations. For emission factors improvement, new on-board measurement campaigns or studies should be undertaken. Regardless of the effort that has been performed in the last years to obtain more accurate shipping emission inventories, more precise input data (technical information about ships, engines, load and emission factors) should be obtained to improve the methodology to develop global and universally accepted emission inventories for an effective environmental policy plan. Copyright © 2017 Elsevier Ltd. All rights reserved.

Modal emissions modeling with real traffic data

DOT National Transportation Integrated Search

1999-01-01

This report details the use of a modal emissions model to estimate the relative emissions of CO due to changes in vehicle operating characteristics on urban roadways. The Davis Institute for Transportation Studies Emissions Model (DITSEM) was selecte...

Use of a portable, automated, open-circuit gas quantification system and the sulfur hexafluoride tracer technique for measuring enteric methane emissions in Holstein cows fed ad libitum or restricted

USDA-ARS?s Scientific Manuscript database

The sulfur hexafluoride tracer technique (SF**6) is a commonly used method for measuring CH**4 enteric emissions in ruminants. Studies using SF**6 have shown large variation in CH**4 emissions data, inconsistencies in CH**4 emissions across studies, and potential methodological errors. Therefore, th...

Update on the development of cotton gin PM10 emission factors for EPA's AP-42

USDA-ARS?s Scientific Manuscript database

A cotton ginning industry-supported project was initiated in 2008 to update the U.S. Environmental Protection Agency’s (EPA) Compilation of Air Pollution Emission Factors (AP-42) to include PM10 emission factors. This study develops emission factors from the PM10 emission factor data collected from ...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heath, Garvin; Warner, Ethan; Steinberg, Daniel

A growing number of studies have raised questions regarding uncertainties in our understanding of methane (CH 4) emissions from fugitives and venting along the natural gas (NG) supply chain. In particular, a number of measurement studies have suggested that actual levels of CH 4 emissions may be higher than estimated by EPA" tm s U.S. GHG Emission Inventory. We reviewed the literature to identify the growing number of studies that have raised questions regarding uncertainties in our understanding of methane (CH 4) emissions from fugitives and venting along the natural gas (NG) supply chain.

Emission of volatile organic compounds (VOCs) from PVC floor coverings.

PubMed

Wiglusz, R; Igielska, B; Sitko, E; Nikel, G; Jarnuszkiewicz, I

1998-01-01

In this study 29 PVC floor coverings were tested for emission of vinyl chloride (VC) and other volatile organic compounds (VOCs). A study on the effect of higher temperature on emission of VOCs from newly manufactured PVC flooring was also carried out. The study was conducted in climatic chamber, according to Polish Standard PN-89/Z-04021. GC method was used for analyzing of the compounds emitted. VC was not emitted from any of the floorings tested. Other VOCs were emitted in different concentrations. The influence of temperature on emission was conducted at temperatures of 23 degrees C and 35 degrees C from 2 hrs up to 180 days after introduction of materials in the chamber. The increase of temperature caused increase of total volatile organic compounds (TVOC) emission during 24 hrs of experiment. Then the emission was comparable for both temperatures. After 9 days emission of identified and unidentified compounds (TVOC) showed a rapid decay and stayed on very low level during a few months. The study conducted showed that PVC floorings after 10 days of installation in the room should not be source of indoor air contamination.

Could the Use of Acoustic Reflexes Prior to Administering Distortion Product Otoacoustic Emissions (DPOAEs) Affect the Results of DPOAEs?

PubMed

Garrette, Rachel; Jones, Alisha L; Wilson, Martha W

2018-05-15

The purpose of this study is to investigate whether acoustic reflex threshold testing before administration of distortion product otoacoustic emissions can affect the results of the distortion product otoacoustic emissions testing using an automated protocol. Fifteen young adults with normal hearing ranging in age from 19 to 25 years participated in the study. All participants had clear external ear canals and normal Jerger Type A tympanograms and had passed a hearing screening. Testing was performed using the Interacoustics Titan acoustic reflex threshold and distortion product otoacoustic emissions protocol. Participants underwent baseline distortion product otoacoustic emissions. A paired-samples t test was conducted for both the right and left ears to assess within-group differences between baseline distortion product otoacoustic emissions and repeated distortion product otoacoustic emissions measures. No significant differences were found in distortion product otoacoustic emission measures following administration of acoustic reflexes. The use of a protocol when using an automated system that includes both acoustic reflexes and distortion product otoacoustic emissions is important. Overall, presentation of acoustic reflexes prior to measuring distortion product otoacoustic emission did not affect distortion product otoacoustic emission results; therefore, test sequence can be modified as needed.

Russian Policy on Methane Emissions in the Oil and Gas Sector: A Case Study in Opportunities and Challenges in Reducing Short-Lived Forcers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Evans, Meredydd; Roshchanka, Volha

2014-08-04

This paper uses Russian policy in the oil and gas sector as a case study in assessing options and challenges for scaling-up emission reductions. We examine the challenges to achieving large-scale emission reductions, successes that companies have achieved to date, how Russia has sought to influence methane emissions through its environmental fine system, and options for helping companies achieve large-scale emission reductions in the future through simpler and clearer incentives.

Diesel engine performance and emissions with fuels derived from waste tyres.

PubMed

Verma, Puneet; Zare, Ali; Jafari, Mohammad; Bodisco, Timothy A; Rainey, Thomas; Ristovski, Zoran D; Brown, Richard J

2018-02-06

The disposal of waste rubber and scrap tyres is a significant issue globally; disposal into stockpiles and landfill poses a serious threat to the environment, in addition to creating ecological problems. Fuel production from tyre waste could form part of the solution to this global issue. Therefore, this paper studies the potential of fuels derived from waste tyres as alternatives to diesel. Production methods and the influence of reactor operating parameters (such as reactor temperature and catalyst type) on oil yield are outlined. These have a major effect on the performance and emission characteristics of diesel engines when using tyre derived fuels. In general, tyre derived fuels increase the brake specific fuel consumption and decrease the brake thermal efficiency. The majority of studies indicate that NOx emissions increase with waste tyre derived fuels; however, a few studies have reported the opposite trend. A similar increasing trend has been observed for CO and CO 2 emissions. Although most studies reported an increase in HC emission owing to lower cetane number and higher density, some studies have reported reduced HC emissions. It has been found that the higher aromatic content in such fuels can lead to increased particulate matter emissions.

Life-cycle energy and greenhouse gas emission benefits of lightweighting in automobiles: review and harmonization.

PubMed

Kim, Hyung Chul; Wallington, Timothy J

2013-06-18

Replacing conventional materials (steel and iron) with lighter alternatives (e.g., aluminum, magnesium, and composites) decreases energy consumption and greenhouse gas (GHG) emissions during vehicle use but may increase energy consumption and GHG emissions during vehicle production. There have been many life cycle assessment (LCA) studies on the benefits of vehicle lightweighting, but the wide variety of assumptions used makes it difficult to compare results from the studies. To clarify the benefits of vehicle lightweighting we have reviewed the available literature (43 studies). The GHG emissions and primary energy results from 33 studies that passed a screening process were harmonized using a common set of assumptions (lifetime distance traveled, fuel-mass coefficient, secondary weight reduction factor, fuel consumption allocation, recycling rate, and energy intensity of materials). After harmonization, all studies indicate that using aluminum, glass-fiber reinforced plastic, and high strength steel to replace conventional steel decreases the vehicle life cycle energy use and GHG emissions. Given the flexibility in options implied by the variety of materials available and consensus that these materials have substantial energy and emissions benefits, it seems likely that lightweighting will be used increasingly to improve fuel economy and reduce life cycle GHG emissions from vehicles.

Idle emissions from heavy-duty diesel and natural gas vehicles at high altitude.

PubMed

McCormick, R L; Graboski, M S; Alleman, T L; Yanowitz, J

2000-11-01

Idle emissions of total hydrocarbon (THC), CO, NOx, and particulate matter (PM) were measured from 24 heavy-duty diesel-fueled (12 trucks and 12 buses) and 4 heavy-duty compressed natural gas (CNG)-fueled vehicles. The volatile organic fraction (VOF) of PM and aldehyde emissions were also measured for many of the diesel vehicles. Experiments were conducted at 1609 m above sea level using a full exhaust flow dilution tunnel method identical to that used for heavy-duty engine Federal Test Procedure (FTP) testing. Diesel trucks averaged 0.170 g/min THC, 1.183 g/min CO, 1.416 g/min NOx, and 0.030 g/min PM. Diesel buses averaged 0.137 g/min THC, 1.326 g/min CO, 2.015 g/min NOx, and 0.048 g/min PM. Results are compared to idle emission factors from the MOBILE5 and PART5 inventory models. The models significantly (45-75%) overestimate emissions of THC and CO in comparison with results measured from the fleet of vehicles examined in this study. Measured NOx emissions were significantly higher (30-100%) than model predictions. For the pre-1999 (pre-consent decree) truck engines examined in this study, idle NOx emissions increased with model year with a linear fit (r2 = 0.6). PART5 nationwide fleet average emissions are within 1 order of magnitude of emissions for the group of vehicles tested in this study. Aldehyde emissions for bus idling averaged 6 mg/min. The VOF averaged 19% of total PM for buses and 49% for trucks. CNG vehicle idle emissions averaged 1.435 g/min for THC, 1.119 g/min for CO, 0.267 g/min for NOx, and 0.003 g/min for PM. The g/min PM emissions are only a small fraction of g/min PM emissions during vehicle driving. However, idle emissions of NOx, CO, and THC are significant in comparison with driving emissions.

Estimation of the emission factors of particle number and mass fractions from traffic at a site where mean vehicle speeds vary over short distances

NASA Astrophysics Data System (ADS)

Jones, Alan M.; Harrison, Roy M.

Emission factors for particle number in three size ranges (11-30; 30-100 and >100 nm) as well as for PM 2.5, PM 2.5-10 and PM 10 mass have been estimated separately for heavy and light-duty vehicles in a heavily trafficked street canyon in London where traffic speeds vary considerably over short distances. Emissions of NO x were estimated from published emission factors, and emissions of other pollutants estimated from their ratio to NO x in the roadside concentration after subtraction of the simultaneously measured urban background. The estimated emission factors are compared with other published data. Despite many differences in the design and implementation of the various studies, the results for particulate matter are broadly similar. Estimates of particle number emissions in this study for light-duty vehicles are very close to other published data, whilst those for heavy-duty vehicles are lower than in the more comparable studies. It is suggested that a contributory factor may be the introduction of diesel particle oxidation traps on some of the bus fleet in London. Estimates of emission factors for particle mass (PM 2.5 and PM 2.5-10) are within the range of other published data, and total mass emissions estimated from the ratio of concentration to NO x are tolerably close to those estimated using emission factors from the National Atmospheric Emissions Inventory (NAEI). However, the method leads to an estimate of carbon monoxide emissions 3-6 times larger than that derived using the NAEI factors.

Comparative toxicity and mutagenicity of soy-biodiesel and petroleum-diesel emissions: overview of studies from the U.S. EPA, Research Triangle Park, NC.

PubMed

Madden, Michael C

2015-01-01

Biodiesel use as a fuel is increasing globally as an alternate to petroleum sources. To comprehensively assess the effects of the use of biodiesel as an energy source, end stage uses of biodiesel such as the effects of inhalation of combusted products on human health must be incorporated. To date, few reports concerning the toxicological effects of the emissions of combusted biodiesel or blends of biodiesel on surrogates of health effects have been published. The relative toxicity of the combusted biodiesel emissions compared to petroleum diesel emissions with short term exposures is also not well known. To address the paucity of findings on the toxicity of combusted biodiesel emissions, studies were undertaken at the U.S. Environmental Protection Agency laboratories in Research Triangle Park, North Carolina. The studies used a variety of approaches with nonhuman animal models to examine biological responses of the lung and cardiovascular systems induced by acute and repeated exposures to pure biodiesel and biodiesel blended with petroleum diesel. Effects of the emissions on induction of mutations in bacterial test strains and mammalian DNA adducts were also characterized and normalized to engine work load. The emissions were characterized as to the physicochemical composition in order to determine the magnitude of the differences among the emissions utilized in the studies. This article summarizes the major finding of these studies which are contained within this special issue of Inhalation Toxicology. The findings provided in these articles provide information about the toxicity of biodiesel emissions relative to petroleum diesel emissions and which can be utilized in a life cycle analyses of the effects of increased biodiesel usage.

Modeling the weekly cycle of NOx and CO emissions and their impacts on O3 in the Los Angeles-South Coast Air Basin during the CalNex 2010 field campaign

NASA Astrophysics Data System (ADS)

Kim, S.-W.; McDonald, B. C.; Baidar, S.; Brown, S. S.; Dube, B.; Ferrare, R. A.; Frost, G. J.; Harley, R. A.; Holloway, J. S.; Lee, H.-J.; McKeen, S. A.; Neuman, J. A.; Nowak, J. B.; Oetjen, H.; Ortega, I.; Pollack, I. B.; Roberts, J. M.; Ryerson, T. B.; Scarino, A. J.; Senff, C. J.; Thalman, R.; Trainer, M.; Volkamer, R.; Wagner, N.; Washenfelder, R. A.; Waxman, E.; Young, C. J.

2016-02-01

We developed a new nitrogen oxide (NOx) and carbon monoxide (CO) emission inventory for the Los Angeles-South Coast Air Basin (SoCAB) expanding the Fuel-based Inventory for motor-Vehicle Emissions and applied it in regional chemical transport modeling focused on the California Nexus of Air Quality and Climate Change (CalNex) 2010 field campaign. The weekday NOx emission over the SoCAB in 2010 is 620 t d-1, while the weekend emission is 410 t d-1. The NOx emission decrease on weekends is caused by reduced diesel truck activities. Weekday and weekend CO emissions over this region are similar: 2340 and 2180 t d-1, respectively. Previous studies reported large discrepancies between the airborne observations of NOx and CO mixing ratios and the model simulations for CalNex based on the available bottom-up emission inventories. Utilizing the newly developed emission inventory in this study, the simulated NOx and CO mixing ratios agree with the observations from the airborne and the ground-based in situ and remote sensing instruments during the field study. The simulations also reproduce the weekly cycles of these chemical species. Both the observations and the model simulations indicate that decreased NOx on weekends leads to enhanced photochemistry and increase of O3 and Ox (=O3 + NO2) in the basin. The emission inventory developed in this study can be extended to different years and other urban regions in the U.S. to study the long-term trends in O3 and its precursors with regional chemical transport models.

Modeling carbon emissions from urban traffic system using mobile monitoring.

PubMed

Sun, Daniel Jian; Zhang, Ying; Xue, Rui; Zhang, Yi

2017-12-01

Comprehensive analyses of urban traffic carbon emissions are critical in achieving low-carbon transportation. This paper started from the architecture design of a carbon emission mobile monitoring system using multiple sets of equipment and collected the corresponding data about traffic flow, meteorological conditions, vehicular carbon emissions and driving characteristics on typical roads in Shanghai and Wuxi, Jiangsu province. Based on these data, the emission model MOVES was calibrated and used with various sensitivity and correlation evaluation indices to analyze the traffic carbon emissions at microscopic, mesoscopic and macroscopic levels, respectively. The major factors that influence urban traffic carbon emissions were investigated, so that emission factors of CO, CO 2 and HC were calculated by taking representative passenger cars as a case study. As a result, the urban traffic carbon emissions were assessed quantitatively, and the total amounts of CO, CO 2 and HC emission from passenger cars in Shanghai were estimated as 76.95kt, 8271.91kt, and 2.13kt, respectively. Arterial roads were found as the primary line source, accounting for 50.49% carbon emissions. In additional to the overall major factors identified, the mobile monitoring system and carbon emission quantification method proposed in this study are of rather guiding significance for the further urban low-carbon transportation development. Copyright © 2017 Elsevier B.V. All rights reserved.

Greenhouse Gas Emissions from Asphalt Pavement Construction: A Case Study in China

PubMed Central

Ma, Feng; Sha, Aimin; Lin, Ruiyu; Huang, Yue; Wang, Chao

2016-01-01

In China, the construction of asphalt pavement has a significant impact on the environment, and energy use and greenhouse gas (GHG) emissions from asphalt pavement construction have been receiving increasing attention in recent years. At present, there is no universal criterion for the evaluation of GHG emissions in asphalt pavement construction. This paper proposes to define the system boundaries for GHG emissions from asphalt pavement by using a process-based life cycle assessment method. A method for evaluating GHG emissions from asphalt pavement construction is suggested. The paper reports a case study of GHG emissions from a typical asphalt pavement construction project in China. The results show that the greenhouse gas emissions from the mixture mixing phase are the highest, and account for about 54% of the total amount. The second highest GHG emission phase is the production of raw materials. For GHG emissions of cement stabilized base/subbase, the production of raw materials emits the most, about 98%. The GHG emission for cement production alone is about 92%. The results indicate that any measures to reduce GHG emissions from asphalt pavement construction should be focused on the raw materials manufacturing stage. If the raw materials production phase is excluded, the measures to reduce GHG emissions should be aimed at the mixture mixing phase. PMID:27011196

Speed Profiles for Improvement of Maritime Emission Estimation

PubMed Central

Yau, Pui Shan; Lee, Shun-Cheng; Ho, Kin Fai

2012-01-01

Abstract Maritime emissions play an important role in anthropogenic emissions, particularly for cities with busy ports such as Hong Kong. Ship emissions are strongly dependent on vessel speed, and thus accurate vessel speed is essential for maritime emission studies. In this study, we determined minute-by-minute high-resolution speed profiles of container ships on four major routes in Hong Kong waters using Automatic Identification System (AIS). The activity-based ship emissions of NOx, CO, HC, CO2, SO2, and PM10 were estimated using derived vessel speed profiles, and results were compared with those using the speed limits of control zones. Estimation using speed limits resulted in up to twofold overestimation of ship emissions. Compared with emissions estimated using the speed limits of control zones, emissions estimated using vessel speed profiles could provide results with up to 88% higher accuracy. Uncertainty analysis and sensitivity analysis of the model demonstrated the significance of improvement of vessel speed resolution. From spatial analysis, it is revealed that SO2 and PM10 emissions during maneuvering within 1 nautical mile from port were the highest. They contributed 7%–22% of SO2 emissions and 8%–17% of PM10 emissions of the entire voyage in Hong Kong. PMID:23236250

Greenhouse Gas Emissions from Asphalt Pavement Construction: A Case Study in China.

PubMed

Ma, Feng; Sha, Aimin; Lin, Ruiyu; Huang, Yue; Wang, Chao

2016-03-22

In China, the construction of asphalt pavement has a significant impact on the environment, and energy use and greenhouse gas (GHG) emissions from asphalt pavement construction have been receiving increasing attention in recent years. At present, there is no universal criterion for the evaluation of GHG emissions in asphalt pavement construction. This paper proposes to define the system boundaries for GHG emissions from asphalt pavement by using a process-based life cycle assessment method. A method for evaluating GHG emissions from asphalt pavement construction is suggested. The paper reports a case study of GHG emissions from a typical asphalt pavement construction project in China. The results show that the greenhouse gas emissions from the mixture mixing phase are the highest, and account for about 54% of the total amount. The second highest GHG emission phase is the production of raw materials. For GHG emissions of cement stabilized base/subbase, the production of raw materials emits the most, about 98%. The GHG emission for cement production alone is about 92%. The results indicate that any measures to reduce GHG emissions from asphalt pavement construction should be focused on the raw materials manufacturing stage. If the raw materials production phase is excluded, the measures to reduce GHG emissions should be aimed at the mixture mixing phase.

Assessment of volatile organic compound and hazardous air pollutant emissions from oil and natural gas well pads using mobile remote and on-site direct measurements.

PubMed

Brantley, Halley L; Thoma, Eben D; Eisele, Adam P

2015-09-01

Emissions of volatile organic compounds (VOCs) and hazardous air pollutants (HAPs) from oil and natural gas production were investigated using direct measurements of component-level emissions on pads in the Denver-Julesburg (DJ) Basin and remote measurements of production pad-level emissions in the Barnett, DJ, and Pinedale basins. Results from the 2011 DJ on-site study indicate that emissions from condensate storage tanks are highly variable and can be an important source of VOCs and HAPs, even when control measures are present. Comparison of the measured condensate tank emissions with potentially emitted concentrations modeled using E&P TANKS (American Petroleum Institute [API] Publication 4697) suggested that some of the tanks were likely effectively controlled (emissions less than 95% of potential), whereas others were not. Results also indicate that the use of a commercial high-volume sampler (HVS) without corresponding canister measurements may result in severe underestimates of emissions from condensate tanks. Instantaneous VOC and HAP emissions measured on-site on controlled systems in the DJ Basin were significantly higher than VOC and HAP emission results from the study conducted by Eastern Research Group (ERG) for the City of Fort Worth (2011) using the same method in the Barnett on pads with low or no condensate production. The measured VOC emissions were either lower or not significantly different from the results of studies of uncontrolled emissions from condensate tanks measured by routing all emissions through a single port monitored by a flow measurement device for 24 hr. VOC and HAP concentrations measured remotely using the U.S. Environmental Protection Agency (EPA) Other Test Method (OTM) 33A in the DJ Basin were not significantly different from the on-site measurements, although significant differences between basins were observed. VOC and HAP emissions from upstream production operations are important due to their potential impact on regional ozone levels and proximate populations. This study provides information on the sources and variability of VOC and HAP emissions from production pads as well as a comparison between different measurement techniques and laboratory analysis protocols. On-site and remote measurements of VOC and HAP emissions from oil and gas production pads indicate that measurable emissions can occur despite the presence of control measures, often as a result of leaking thief hatch seals on condensate tanks. Furthermore, results from the remote measurement method OTM 33A indicate that it can be used effectively as an inspection technique for identifying oil and gas well pads with large fugitive emissions.

An introduction to human biophoton emission.

PubMed

Wijk, Roeland Van; Wijk, Eduard P A Van

2005-04-01

Biophoton emission is the spontaneous emission of ultraweak light emanating from all living systems, including man. The emission is linked to the endogenous production of excited states within the living system. The detection and characterisation of human biophoton emission has led to suggestions that it has potential future applications in medicine. An overview is presented of studies on ultraweak photon emission (UPE, biophotons) from the human whole body. Electronic searches of Medline, PsychLit, PubMed and references lists of relevant review articles and books were used to establish the literature database. Articles were then analysed for their main experimental setup and results. The, mostly, single case studies have resulted in a collection of observations. The collection presents information on the following fields of research: (1) influence of biological rhythms, age, and gender on emission, (2) the intensity of emission and its left-right symmetry in health and disease, (3) emission from the perspective of Traditional Chinese and Korean Medicine, (4) emission in different consciousness studies, (5) procedures for analysis of the photon signal from hands, (6) detection of peroxidative processes in the skin. Of each article the main findings are presented in a qualitative manner, quantitative data are presented where useful, and the technological or methodological limitations are discussed. Photon emission recording techniques have reached a stage that allows resolution of the signal in time and space. The published material is presented and includes aspects like spatial resolution of intensity, its relation to health and disease, the aspect of colour, and methods for analysis of the photon signal. The limited number of studies only allows first conclusions about the implications and significance of biophotons in relation to health and disease, or to mental states, or acupuncture. However, with the present data we consider that further research in the field is justified.

A pilot study to determine medical laser generated air contaminant emission rates for a simulated surgical procedure.

PubMed

Lippert, Julia F; Lacey, Steven E; Lopez, Ramon; Franke, John; Conroy, Lorraine; Breskey, John; Esmen, Nurtan; Liu, Li

2014-01-01

The U.S. Occupational Safety and Health Administration (OSHA) estimates that half a million health-care workers are exposed to laser surgical smoke each year. The purpose of this study was to establish a methodology to (1) estimate emission rates of laser-generated air contaminants (LGACs) using an emission chamber, and to (2) perform a screening study to differentiate the effects of three laser operational parameters. An emission chamber was designed, fabricated, and assessed for performance to estimate the emission rates of gases and particles associated with LGACs during a simulated surgical procedure. Two medical lasers (Holmium Yttrium Aluminum Garnet [Ho:YAG] and carbon dioxide [CO2]) were set to a range of plausible medical laser operational parameters in a simulated surgery to pyrolyze porcine skin generating plume in the emission chamber. Power, pulse repetition frequency (PRF), and beam diameter were evaluated to determine the effect of each operational parameter on emission rate using a fractional factorial design. The plume was sampled for particulate matter and seven gas phase combustion byproduct contaminants (benzene, ethylbenzene, toluene, formaldehyde, hydrogen cyanide, carbon dioxide, and carbon monoxide): the gas phase emission results are presented here. Most of the measured concentrations of gas phase contaminants were below their limit of detection (LOD), but detectable measurements enabled us to determine laser operation parameter influence on CO2 emissions. Confined to the experimental conditions of this screening study, results indicated that beam diameter was statistically significantly influential and power was marginally statistically significant to emission rates of CO2 when using the Ho:YAG laser but not with the carbon dioxide laser; PRF was not influential vis-a-vis emission rates of these gas phase contaminants.

Road traffic emission factors for heavy metals

NASA Astrophysics Data System (ADS)

Johansson, Christer; Norman, Michael; Burman, Lars

Quantifying the emissions and concentrations of heavy metals in urban air is a prerequisite for assessing their health effects. In this paper a combination of measurements and modelling is used to assess the contribution from road traffic emissions. Concentrations of particulate heavy metals in air were measured simultaneously during 1 year at a densely trafficked street and at an urban background site in Stockholm, Sweden. Annual mean concentrations of cadmium were 50 times lower than the EU directive and for nickel and arsenic concentrations were 10 and six times lower, respectively. More than a factor of two higher concentrations was in general observed at the street in comparison to roof levels indicating the strong influence from local road traffic emissions. The only compound with a significantly decreasing trend in the urban background was Pb with 9.1 ng m -3 in 1995/96 compared to 3.4 ng m -3 2003/04. This is likely due to decreased emissions from wear of brake linings and reduced emissions due to oil and coal combustion in central Europe. Total road traffic emission factors for heavy metals were estimated using parallel measurements of NOx concentrations and knowledge of NOx emission factors. In general, the emission factors for the street were higher than reported in road tunnel measurements. This could partly be due to different driving conditions, since especially for metals which are mainly emitted from brake wear, more stop and go driving in the street compared to in road tunnels is likely to increase emissions. Total emissions were compared with exhaust emissions, obtained from the COPERT model and brake wear emissions based on an earlier study in Stockholm. For Cu, Ni and Zn the sum of brake wear and exhaust emissions agreed very well with estimated total emission factors in this study. More than 90% of the road traffic emissions of Cu were due to brake wear. For Ni more than 80% is estimated to be due to exhaust emissions and for Zn around 40% of road traffic emissions are estimated to be due to exhaust emissions. Pb is also mainly due to exhaust emissions (90%); a fuel Pb content of only 0.5 mg L -1 would give similar emission factor as that based on the concentration increment at the street. This is the first study using simultaneous measurements of heavy metals at street and roof enabling calculations of emission factors using a tracer technique.

Russian anthropogenic black carbon: Emission reconstruction and Arctic black carbon simulation

NASA Astrophysics Data System (ADS)

Huang, Kan; Fu, Joshua S.; Prikhodko, Vitaly Y.; Storey, John M.; Romanov, Alexander; Hodson, Elke L.; Cresko, Joe; Morozova, Irina; Ignatieva, Yulia; Cabaniss, John

2015-11-01

Development of reliable source emission inventories is particularly needed to advance the understanding of the origin of Arctic haze using chemical transport modeling. This study develops a regional anthropogenic black carbon (BC) emission inventory for the Russian Federation, the largest country by land area in the Arctic Council. Activity data from combination of local Russia information and international resources, emission factors based on either Russian documents or adjusted values for local conditions, and other emission source data are used to approximate the BC emissions. Emissions are gridded at a resolution of 0.1° × 0.1° and developed into a monthly temporal profile. Total anthropogenic BC emission of Russia in 2010 is estimated to be around 224 Gg. Gas flaring, a commonly ignored black carbon source, contributes a significant fraction of 36.2% to Russia's total anthropogenic BC emissions. Other sectors, i.e., residential, transportation, industry, and power plants, contribute 25.0%, 20.3%, 13.1%, and 5.4%, respectively. Three major BC hot spot regions are identified: the European part of Russia, the southern central part of Russia where human population densities are relatively high, and the Urals Federal District where Russia's major oil and gas fields are located but with sparse human population. BC simulations are conducted using the hemispheric version of Community Multi-scale Air Quality Model with emission inputs from a global emission database EDGAR (Emissions Database for Global Atmospheric Research)-HTAPv2 (Hemispheric Transport of Air Pollution) and EDGAR-HTAPv2 with its Russian part replaced by the newly developed Russian BC emissions, respectively. The simulation using the new Russian BC emission inventory could improve 30-65% of absorption aerosol optical depth measured at the AERONET sites in Russia throughout the whole year as compared to that using the default HTAPv2 emissions. At the four ground monitoring sites (Zeppelin, Barrow, Alert, and Tiksi) in the Arctic Circle, surface BC simulations are improved the most during the Arctic haze periods (October-March). The poor performance of Arctic BC simulations in previous studies may be partly ascribed to the Russian BC emissions built on out-of-date and/or missing information, which could result in biases to both emission rates and the spatial distribution of emissions. This study highlights that the impact of Russian emissions on the Arctic haze has likely been underestimated, and its role in the Arctic climate system needs to be reassessed. The Russian black carbon emission source data generated in this study can be obtained via http://abci.ornl.gov/download.shtml or http://acs.engr.utk.edu/Data.php.

Measurement of gas and aerosol agricultural emissions

USDA-ARS?s Scientific Manuscript database

Studies of air quality indicate that agricultural emissions may impact particulate mass concentrations through both primary and secondary processes. Agriculture impacts can include primary dust emission, on-facility combustion from vehicles or seasonal field burning, and gaseous emissions from waste...

Assessment of vehicle emission programs in China during 1998-2013: Achievement, challenges and implications.

PubMed

Wu, Xiaomeng; Wu, Ye; Zhang, Shaojun; Liu, Huan; Fu, Lixin; Hao, Jiming

2016-07-01

China has been embracing rapid motorization since the 1990s, and vehicles have become one of the major sources of air pollution problems. Since the late 1990s, thanks to the international experience, China has adopted comprehensive control measures to mitigate vehicle emissions. This study employs a local emission model (EMBEV) to assess China's first fifteen-year (1998-2013) efforts in controlling vehicles emissions. Our results show that China's total annual vehicle emissions in 2013 were 4.16 million tons (Mt) of HC, 27.4 Mt of CO, 7.72 Mt of NOX, and 0.37 Mt of PM2.5, respectively. Although vehicle emissions are substantially reduced relative to the without control scenarios, we still observe significantly higher emission density in East China than in developed countries with longer histories of vehicle emission control. This study further informs China's policy-makers of the prominent challenges to control vehicle emissions in the future. First, unlike other major air pollutants, total NOX emissions have rapidly increased due to a surge of diesel trucks and the postponed China IV standard nationwide. Simultaneous implementation of fuel quality improvements and vehicle-engine emission standards will be of great importance to alleviate NOX emissions for diesel fleets. Second, the enforcement of increasingly stringent standards should include strict oversight of type-approval conformity, in-use complacence and durability, which would help reduce gross emitters of PM2.5 that are considerable among in-use diesel fleets at the present. Third, this study reveals higher HC emissions than previous results and indicates evaporative emissions may have been underestimated. Considering that China's overall vehicle ownership is far from saturation, persistent efforts are required through economic tools, traffic management and emissions regulations to lower vehicle-use intensity and limit both exhaust and evaporative emissions. Furthermore, in light of the complex technology for emerging new energy vehicles, their real-world emissions need to be adequately evaluated before massive promotion. Copyright © 2016 Elsevier Ltd. All rights reserved.

Breathing easier? The known impacts of biodiesel on air quality

PubMed Central

Traviss, Nora

2013-01-01

Substantial scientific evidence exists on the negative health effects of exposure to petroleum diesel exhaust. Many view biodiesel as a ‘green’, more environmentally friendly alternative fuel, especially with respect to measured reductions of particulate matter in tailpipe emissions. Tailpipe emissions data sets from heavy-duty diesel engines comparing diesel and biodiesel fuels provide important information regarding the composition and potential aggregate contribution of particulate matter and other pollutants to regional airsheds. However, exposure – defined in this instance as human contact with tailpipe emissions – is another key link in the chain between emissions and human health effects. Although numerous biodiesel emissions studies exist, biodiesel exposure studies are nearly absent from the literature. This article summarizes the known impacts of biodiesel on air quality and health effects, comparing emissions and exposure research. In light of rapidly changing engine, fuel and exhaust technologies, both emissions and exposure studies are necessary for developing a fuller understanding of the impact of biodiesel on air quality and human health. PMID:23585814

A Direct Measurement Study of Air Emissions from Oil & Natural Gas Production Pads in the Denver-Julesburg Basin

EPA Science Inventory

EPA and industry cooperators conducted a one-week emission measurement study of 23 oil and natural gas well pads in the Denver-Julesburg Basin in July, 2011. The purpose of the study was to characterize emissions from individual production components and to evaluate the performa...

A Direct Measurement Study of Air Emissions from Oil & Natural Gas Production Pads in the DJ Basin

EPA Science Inventory

EPA and industry cooperators conducted a one-week emission measurement study of 23 oil and natural gas well pads in the Denver-Julesburg Basin in July, 2011. The purpose of the study was to characterize emissions from individual production components and to evaluate the performa...

Development of the Vista Methane Emissions Inventory for Southern California: A GIS-Based Approach for Mapping Methane Emissions

NASA Astrophysics Data System (ADS)

Carranza, V.; Frausto-Vicencio, I.; Rafiq, T.; Verhulst, K. R.; Hopkins, F. M.; Rao, P.; Duren, R. M.; Miller, C. E.

2016-12-01

Atmospheric methane (CH4) is the second most prevalent anthropogenic greenhouse gas. Improved estimates of CH4 emissions from cities is essential for carbon cycle science and climate mitigation efforts. Development of spatially-resolved carbon emissions data sets may offer significant advances in understanding and managing carbon emissions from cities. Urban CH4 emissions in particular require spatially resolved emission maps to help resolve uncertainties in the CH4 budget. This study presents a Geographic Information System (GIS)-based approach to mapping CH4 emissions using locations of infrastructure known to handle and emit methane. We constrain the spatial distribution of sources to the facility level for the major CH4 emitting sources in the South Coast Air Basin. GIS spatial modeling was combined with publicly available datasets to determine the distribution of potential CH4 sources. The datasets were processed and validated to ensure accuracy in the location of individual sources. This information was then used to develop the Vista emissions prior, which is a one-year long, spatially-resolved CH4 emissions estimate. Methane emissions were calculated and spatially allocated to produce 1 km x 1 km gridded CH4 emission map spanning the Los Angeles Basin. In future work, the Vista CH4 emissions prior will be compared with existing, coarser-resolution emissions estimates and will be evaluated in inverse modeling studies using atmospheric observations. The Vista CH4 emissions inventory presents the first detailed spatial maps of CH4 sources and emissions estimates in the Los Angeles Basin and is a critical step towards sectoral attribution of CH4 emissions at local to regional scales.

Effect of lower and higher alcohol fuel synergies in biofuel blends and exhaust treatment system on emissions from CI engine.

PubMed

Subramanian, Thiyagarajan; Varuvel, Edwin Geo; Martin, Leenus Jesu; Beddhannan, Nagalingam

2017-11-01

The present study deals with performance, emission and combustion studies in a single cylinder CI engine with lower and higher alcohol fuel synergies with biofuel blends and exhaust treatment system. Karanja oil methyl ester (KOME), widely available biofuel in India, and orange oil (ORG), a low carbon biofuel, were taken for this study, and equal volume blend was prepared for testing. Methanol (M) and n-pentanol (P) was taken as lower and higher alcohol and blended 20% by volume with KOME-ORG blend. Activated carbon-based exhaust treatment indigenous system was designed and tested with KOME-ORG + M20 and KOME-ORG + P20 blend. The tests were carried out at various load conditions at a constant speed of 1500 rpm. The study revealed that considering performance, emission and combustion studies, KOME-ORG + M20 + activated carbon are found optimum in reducing NO, smoke and CO 2 emission. Compared to KOME, for KOME-ORG + M20 + activated carbon, NO emission is reduced from 10.25 to 7.85 g/kWh, the smoke emission is reduced from 49.4 to 28.9%, and CO 2 emission is reduced from 1098.84 to 580.68 g/kWh. However, with exhaust treatment system, an increase in HC and CO emissions and reduced thermal efficiency is observed due to backpressure effects.

Atmospheric modeling to assess wind dependence in tracer dilution method measurements of landfill methane emissions.

PubMed

Taylor, Diane M; Chow, Fotini K; Delkash, Madjid; Imhoff, Paul T

2018-03-01

The short-term temporal variability of landfill methane emissions is not well understood due to uncertainty in measurement methods. Significant variability is seen over short-term measurement campaigns with the tracer dilution method (TDM), but this variability may be due in part to measurement error rather than fluctuations in the actual landfill emissions. In this study, landfill methane emissions and TDM-measured emissions are simulated over a real landfill in Delaware, USA using the Weather Research and Forecasting model (WRF) for two emissions scenarios. In the steady emissions scenario, a constant landfill emissions rate is prescribed at each model grid point on the surface of the landfill. In the unsteady emissions scenario, emissions are calculated at each time step as a function of the local surface wind speed, resulting in variable emissions over each 1.5-h measurement period. The simulation output is used to assess the standard deviation and percent error of the TDM-measured emissions. Eight measurement periods are simulated over two different days to look at different conditions. Results show that standard deviation of the TDM- measured emissions does not increase significantly from the steady emissions simulations to the unsteady emissions scenarios, indicating that the TDM may have inherent errors in its prediction of emissions fluctuations. Results also show that TDM error does not increase significantly from the steady to the unsteady emissions simulations. This indicates that introducing variability to the landfill emissions does not increase errors in the TDM at this site. Across all simulations, TDM errors range from -15% to 43%, consistent with the range of errors seen in previous TDM studies. Simulations indicate diurnal variations of methane emissions when wind effects are significant, which may be important when developing daily and annual emissions estimates from limited field data. Copyright © 2017 Elsevier Ltd. All rights reserved.

Transient Evoked and Distortion Product Otoacoustic Emissions in a Group of Neonates

PubMed Central

Silva, Giovanna Cesar; Delecrode, Camila Ribas; Kemp, Adriana Tahara; Martins, Fabiana; Cardoso, Ana Claudia Vieira

2015-01-01

Introduction The most commonly used method in neonatal hearing screening programs is transient evoked otoacoustic emissions in the first stage of the process. There are few studies comparing transient evoked otoacoustic emissions with distortion product, but some authors have investigated the issue. Objective To correlate the results of transient evoked and distortion product otoacoustic emissions in a Brazilian maternity hospital. Methods This is a cross-sectional, comparative, and prospective study. The study included 579 newborns, ranging from 6 to 54 days of age, born in a low-risk maternity hospital and assessed for hearing loss. All neonates underwent hearing screening by transient evoked and distortion product otoacoustic emissions. The results were analyzed using the Spearman correlation test to relate the two procedures. Results The pass index on transient evoked otoacoustic emissions was 95% and on distortion product otoacoustic emissions was 91%. The comparison of the two procedures showed that 91% of neonates passed on both procedures, 4.5% passed only on transient evoked otoacoustic emissions, 0.5% passed only on distortion product otoacoustic emissions, and 4% failed on both procedures. The inferential analysis showed a significant strong positive relationship between the two procedures. Conclusion The failure rate was higher in distortion product otoacoustic emissions when compared with transient evoked; however, there was correlation between the results of the procedures. PMID:26157501

The sound of orthopaedic surgery--the application of acoustic emission technology in orthopaedic surgery: a review.

PubMed

Rashid, Mustafa S; Pullin, Rhys

2014-01-01

Acoustic emission technology has been developed and extensively used as a non-destructive method of testing within engineering. In recent years, acoustic emission has gained popularity within the field of Orthopaedic research in a variety of situations. It is an attractive method in the detection of flaws within structures due its high sensitivity and non-destructive nature. The aim of this article is firstly to critically review the research conducted using acoustic emission testing in a variety of Orthopaedic-related situations and to present the technique to the wider Orthopaedic community. A summary of the principles and practical aspects of using acoustic emission testing are outlined. Acoustic emission has been validated as a method of early detection of aseptic loosening in femoral components in total hip arthroplasty in several well-conducted in vitro studies [1-3]. Other studies have used acoustic emission to detect microdamage in bone and to assess the biomechanical properties of bone and allografts [9]. Researchers have also validated the use of acoustic emission to detect and monitor fracture healing [4]. Several studies have applied acoustic emission to spinal surgery and specifically to assess the biomechanical environment in titanium mesh cages used in spinal surgery [10, 11]. Despite its growing popularity within Orthopaedic research, acoustic emission remains are relatively unfamiliar technique to the majority of Orthopaedic surgeons.

Aircraft-Based Measurements of Point Source Methane Emissions in the Barnett Shale Basin.

PubMed

Lavoie, Tegan N; Shepson, Paul B; Cambaliza, Maria O L; Stirm, Brian H; Karion, Anna; Sweeney, Colm; Yacovitch, Tara I; Herndon, Scott C; Lan, Xin; Lyon, David

2015-07-07

We report measurements of methane (CH4) emission rates observed at eight different high-emitting point sources in the Barnett Shale, Texas, using aircraft-based methods performed as part of the Barnett Coordinated Campaign. We quantified CH4 emission rates from four gas processing plants, one compressor station, and three landfills during five flights conducted in October 2013. Results are compared to other aircraft- and surface-based measurements of the same facilities, and to estimates based on a national study of gathering and processing facilities emissions and 2013 annual average emissions reported to the U.S. EPA Greenhouse Gas Reporting Program (GHGRP). For the eight sources, CH4 emission measurements from the aircraft-based mass balance approach were a factor of 3.2-5.8 greater than the GHGRP-based estimates. Summed emissions totaled 7022 ± 2000 kg hr(-1), roughly 9% of the entire basin-wide CH4 emissions estimated from regional mass balance flights during the campaign. Emission measurements from five natural gas management facilities were 1.2-4.6 times larger than emissions based on the national study. Results from this study were used to represent "super-emitters" in a newly formulated Barnett Shale Inventory, demonstrating the importance of targeted sampling of "super-emitters" that may be missed by random sampling of a subset of the total.

Framework for Assessing Biogenic CO2 Emissions from ...

EPA Pesticide Factsheets

This revision of the 2011 report, Accounting Framework for Biogenic CO2 Emissions from Stationary Sources, evaluates biogenic CO2 emissions from stationary sources, including a detailed study of the scientific and technical issues associated with assessing biogenic carbon dioxide emissions from stationary sources. EPA developed the revised report, Framework for Assessing Biogenic CO2 Emissions from Stationary Sources, to present a methodological framework for assessing the extent to which the production, processing, and use of biogenic material at stationary sources for energy production results in a net atmospheric contribution of biogenic CO2 emissions. Biogenic carbon dioxide emissions are defined as CO2 emissions related to the natural carbon cycle, as well as those resulting from the production, harvest, combustion, digestion, decomposition, and processing of biologically-based materials. The EPA is continuing to refine its technical assessment of biogenic CO2 emissions through another round of targeted peer review of the revised study with the EPA Science Advisory Board (SAB). This study was submitted to the SAB's Biogenic Carbon Emissions Panel in February 2015. http://yosemite.epa.gov/sab/sabproduct.nsf/0/3235dac747c16fe985257da90053f252!OpenDocument&TableRow=2.2#2 The revised report will inform efforts by policymakers, academics, and other stakeholders to evaluate the technical aspects related to assessments of biogenic feedstocks used for energy at s

2D-model of oxygen emissions lines for Europa

NASA Astrophysics Data System (ADS)

Cessateur, Gaël; Barthelemy, Mathieu; Lilensten, Jean; Rubin, Martin; Maggiolo, Romain; De Keyser, Johan

2017-04-01

The Jovian moon Europa is an interesting case study as an archetype for icy satellites, and will be one of the primary targets of the ESA JUICE mission which should be launched in 2022. Hosting a thin neutral gas atmosphere mainly composed of O2 and H2O, Europa can be studied by its airglow and dayglow emissions. A 1D photochemistry model has first been developed to assess the impact of the solar UV flux on the visible emission, such as the red and green oxygen lines (Cessateur et al. 2016). For limb polar viewing, red line emissions can reach a few hundreds of Rayleigh close to the surface. The impact of the precipitating electrons has also been studied. The density and temperature of the electrons are first derived from the multifluid MHD model from Rubin et al. (2015). A 2D emission model has thus been developed to estimate the airglow emissions. When electrons are the major source of the visible emissions, the solar UV flux can be responsible for up to 15% of those emissions for some specific line of sight. Oxygen emission lines in the UV have also been considered, such as 130.5 and 135.6 nm. For the latter, we did estimate some significant line emissions reaching 700 Rayleigh for a polar limb viewing angle close to the surface. Oxygen emission lines are significant (higher than 10 R) for altitudes lower than 100 km for all lines, except for the red line emissions where emissions are still above 10 R up to 200 km from the surface. A sensitivity study has also been performed in order to assess the impact of the uncertainties relative to the dissociative-excitation cross sections. Cessateur G, Barthelemy M & Peinke I. Photochemistry-emission coupled model for Europa and Ganymede. J. Space Weather Space Clim., 6, A17, 2016 Rubin, M., et al. Self-consistent multifluid MHD simulations of Europa's exospheric interaction with Jupiter's magnetosphere, J. Geophys. Res. Space Physics, 120, 3503-3524, 2015

Ammonia emission inventory for the state of Wyoming

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kirchstetter, Thomas W.; Maser, Colette R.; Brown, Nancy J.

2003-12-17

Ammonia (NH{sub 3}) is the only significant gaseous base in the atmosphere and it has a variety of impacts as an atmospheric pollutant, including the formation of secondary aerosol particles: ammonium sulfate and ammonium nitrate. NH{sub 3} preferentially forms ammonium sulfate; consequently ammonium nitrate aerosol formation may be limited by the availability of NH{sub 3}. Understanding the impact of emissions of oxides of sulfur and nitrogen on visibility, therefore, requires accurately determined ammonia emission inventories for use in air quality models, upon which regulatory and policy decisions increasingly depend. This report presents an emission inventory of NH{sub 3} for themore » state of Wyoming. The inventory is temporally and spatially resolved at the monthly and county level, and is comprised of emissions from individual sources in ten categories: livestock, fertilizer, domestic animals, wild animals, wildfires, soil, industry, mobile sources, humans, and publicly owned treatment works. The Wyoming NH{sub 3} inventory was developed using the Carnegie Mellon University (CMU) Ammonia Model as framework. Current Wyoming-specific activity data and emissions factors obtained from state agencies and published literature were assessed and used as inputs to the CMU Ammonia Model. Biogenic emissions from soils comprise about three-quarters of the Wyoming NH{sub 3} inventory, though emission factors from soils are highly uncertain. Published emission factors are scarce and based on limited measurements. In Wyoming, agricultural land, rangeland, and forests comprise 96% of the land area and essentially all of the estimated emissions from soils. Future research on emission rates of NH{sub 3} for these land categories may lead to a substantial change in the magnitude of soil emissions, a different inventory composition, and reduced uncertainty in the inventory. While many NH{sub 3} inventories include annual emissions, air quality modeling studies require finer temporal resolution. Published studies indicate higher emission rates from soils and animal wastes at higher temperatures, and temporal variation in fertilizer application. A recent inverse modeling study indicates temporal variation in regional NH{sub 3} emissions. Monthly allocation factors were derived to estimate monthly emissions from soils, livestock and wild animal waste based on annual emission estimates. Monthly resolution of NH{sub 3} emissions from fertilizers is based on fertilizer sales to farmers. Statewide NH{sub 3} emissions are highest in the late spring and early summer months.« less

The difference between laboratory and in-situ pixel-averaged emissivity: The effects on temperature-emissivity separation

NASA Technical Reports Server (NTRS)

Matsunaga, Tsuneo

1993-01-01

Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is a Japanese future imaging sensor which has five channels in thermal infrared (TIR) region. To extract spectral emissivity information from ASTER and/or TIMS data, various temperature-emissivity (T-E) separation methods have been developed to date. Most of them require assumptions on surface emissivity, in which emissivity measured in a laboratory is often used instead of in-situ pixel-averaged emissivity. But if these two emissivities are different, accuracies of separated emissivity and surface temperature are reduced. In this study, the difference between laboratory and in-situ pixel-averaged emissivity and its effect on T-E separation are discussed. TIMS data of an area containing both rocks and vegetation were also processed to retrieve emissivity spectra using two T-E separation methods.

[Study on emission standard system of air pollutants].

PubMed

Jiang, Mei; Zhang, Guo-Ning; Zhang, Ming-Hui; Zou, Lan; Wei, Yu-Xia; Ren, Chun

2012-12-01

Scientific and reasonable emission standard system of air pollutants helps to systematically control air pollution, enhance the protection of the atmospheric environment effect and improve the overall atmospheric environment quality. Based on the study of development, situation and characteristics of national air pollutants emission standard system, the deficiencies of system were pointed out, which were not supportive, harmonious and perfect, and the improvement measures of emission standard system were suggested.

Water regime-nitrogen fertilizer incorporation interaction: Field study on methane and nitrous oxide emissions from a rice agroecosystem in Harbin, China.

PubMed

Dong, Wenjun; Guo, Jia; Xu, Lijun; Song, Zhifeng; Zhang, Jun; Tang, Ao; Zhang, Xijuan; Leng, Chunxu; Liu, Youhong; Wang, Lianmin; Wang, Lizhi; Yu, Yang; Yang, Zhongliang; Yu, Yilei; Meng, Ying; Lai, Yongcai

2018-02-01

Water regime and nitrogen (N) fertilizer are two important factors impacting greenhouse gases (GHG) emission from paddy field, whereas their effects have not been well studied in cold region. In this study, we conducted a two-year field experiment to study the impacts of water regime and N fertilizer on rice yields and GHG emissions in Harbin, China, a cold region located in high latitudes. Our results showed that intermittent irrigation significantly decreased methane (CH 4 ) emission compared with continuous flooding, however, the decrement was far lower than the global average level. The N 2 O emissions were very small when flooded but peaked at the beginning of the disappearance of floodwater. The N fertilizer treatments increased CH 4 emissions at low level (75kgN/ha). But both CH 4 and N 2 O emissions were uninfluenced at the levels of 150kgN/ha and 225kgN/ha. Rice yields increased under intermittent irrigation and were highest at the level of 150kgN/ha. From our results, we recommended that the intermittent irrigation and 150kgN/ha as the ideal water regime-nitrogen fertilizer incorporation for this area to achieve low GHG emissions without impacting rice yields. Copyright © 2017. Published by Elsevier B.V.

FT-IR spectroscopic studies of polycyclic aromatic hydrocarbons

NASA Technical Reports Server (NTRS)

Salisbury, D. W.; Allen, J. E., Jr.; Donn, B.; Moore, W. J.; Khanna, R. K.

1990-01-01

Proper assessment of the hypothesis which correlates polycyclic aromatic hydrocarbons (PAHs) with the unidentified infrared emission bands requires additional experimental laboratory data. In order to address this need, thermal infrared emission studies were performed on a subset of PAHs suggested to be of astrophysical importance. It was proposed that infrared emission from interstellar PAHs occurs following absorption of an ultraviolet photon. Since energy transfer to the ground electronic state can be rapid for a species in which intersystem crossing is negligible, the emission spectrum may be viewed as resulting from an equilibrium vibrational temperature (Leger and d'Hendecourt, 1987). This has been the basis for using infrared absorption spectra to calculate the corresponding emission spectra at various temperatures. These calculations were made using room temperature infrared absorption coefficients instead of those at the temperature of interest because of the latter's unavailability. The present studies are designed to address the differences between the calculated and experimental thermal emission spectra and to provide information which will be useful in future ultraviolet induced infrared fluorescence studies. The emission spectra have been obtained for temperatures up to 825K using an emission cell designed to mount against an external port of an FT-IR spectrometer. These spectra provide information concerning relative band intensities and peak positions which is unavailable from previous calculations.

Trends in exhaust emissions from in-use Mexico City vehicles, 2000-2006. A remote sensing study.

PubMed

Schifter, I; Díaz, L; Rodríguez, R; Durán, J; Chávez, O

2008-02-01

A remote sensing study was conducted in year 2006 in four locations of the Metropolitan Area of Mexico City (MAMC). Two of the sites were the same studied back by us in year 2000 and by others in year 1994. A database was compiled containing 11,289 valid measurements for the carbon monoxide (CO), total hydrocarbons (THC), and nitric oxide (NO) exhaust vehicles emissions. Valid measurements were binned for each pollutant by the vehicle specific power (between -5 and 20 kW tonne(-1)) for the 2000 and 2006 databases. The mean average CO, THC, and NO emissions for year 2006 were determined to be 1.10 +/- 0.18 vol.%, 299 +/- 88.4 ppm, and 610 +/- 115.0 ppm, respectively. Matching the vehicle driving patterns of the fleet measured in year 2000 with the emissions factors obtained in this work, allows estimating the trends in the exhaust emissions of vehicles in the MAMC. The adjusted results of the remote sensing study performed in year 2006 shows that the fleet has decrease 22% in CO and 17% in NO emissions, with small change in total hydrocarbons emissions. The improvements could be related with the introduction in year 2001 of vehicles that met tighter emissions standards, particularly for nitrogen oxides.

Reduction in soil N2O emissions by pH manipulation and enhanced nosZ gene transcription under different water regimes.

PubMed

Shaaban, Muhammad; Wu, Yupeng; Khalid, Muhammad Salman; Peng, Qi-An; Xu, Xiangyu; Wu, Lei; Younas, Aneela; Bashir, Saqib; Mo, Yongliang; Lin, Shan; Zafar-Ul-Hye, Muhammad; Abid, Muhammad; Hu, Ronggui

2018-04-01

Several studies have been carried out to examine nitrous oxide (N 2 O) emissions from agricultural soils in the past. However, the emissions of N 2 O particularly during amelioration of acidic soils have been rarely studied. We carried out the present study using a rice-rapeseed rotation soil (pH 5.44) that was amended with dolomite (0, 1 and 2 g kg -1 soil) under 60% water filled pore space (WFPS) and flooding. N 2 O emissions and several soil properties (pH, NH 4 + N, NO 3 - -N, and nosZ gene transcripts) were measured throughout the study. The increase in soil pH with dolomite application triggered soil N transformation and transcripts of nosZ gene controlling N 2 O emissions under both water regimes (60% WFPS and flooding). The 60% WFPS produced higher soil N 2 O emissions than that of flooding, and dolomite largely reduced N 2 O emissions at higher pH under both water regimes through enhanced transcription of nosZ gene. The results suggest that ameliorating soil acidity with dolomite can substantially mitigate N 2 O emissions through promoting nosZ gene transcription. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Study of Biogenetic Organic Compound Emissions and Ozone in a Subtropical Bamboo Forest

NASA Astrophysics Data System (ADS)

Bai, Jianhui; Guenther, Alex; Turnipseed, Andrew; Duhl, Tiffany; Duhl, Nanhao; van der A, Ronald; Yu, Shuquan; Wang, Bin

2016-08-01

Emissions of Biogenic Volatile Organic compounds (BVOCs), Photosynthetically Active Radiation (PAR), and meteorological parameters were measured in some ecosystems in China. A Relaxed Eddy Accumulation system and an enclosure technique were used to measure BVOC emissions. Obvious diurnal and seasonal variations of BVOC emissions were found. Empirical models of BVOC emissions were developed, the estimated BVOC emissions were in agreement with observations. BVOC emissions in growing seasons in the Inner Mongolia grassland, Chnagbai Mountain temperate forest, LinAn subtropical bamboo forest were estimated. The emission factors of these ecosystems were calculated.

Update on the development of cotton gin PM2.5 emission factors for EPA's AP-42

USDA-ARS?s Scientific Manuscript database

A cotton ginning industry-supported project was initiated in 2008 to update the U.S. Environmental Protection Agency’s (EPA) Compilation of Air Pollution Emission Factors (AP-42) to include PM2.5 emission factors. This study develops emission factors from the PM2.5 emission factor data collected fro...

Estimating Vehicle Fuel Consumption and Emissions Using GPS Big Data

PubMed Central

Kan, Zihan; Zhang, Xia

2018-01-01

The energy consumption and emissions from vehicles adversely affect human health and urban sustainability. Analysis of GPS big data collected from vehicles can provide useful insights about the quantity and distribution of such energy consumption and emissions. Previous studies, which estimated fuel consumption/emissions from traffic based on GPS sampled data, have not sufficiently considered vehicle activities and may have led to erroneous estimations. By adopting the analytical construct of the space-time path in time geography, this study proposes methods that more accurately estimate and visualize vehicle energy consumption/emissions based on analysis of vehicles’ mobile activities (MA) and stationary activities (SA). First, we build space-time paths of individual vehicles, extract moving parameters, and identify MA and SA from each space-time path segment (STPS). Then we present an N-Dimensional framework for estimating and visualizing fuel consumption/emissions. For each STPS, fuel consumption, hot emissions, and cold start emissions are estimated based on activity type, i.e., MA, SA with engine-on and SA with engine-off. In the case study, fuel consumption and emissions of a single vehicle and a road network are estimated and visualized with GPS data. The estimation accuracy of the proposed approach is 88.6%. We also analyze the types of activities that produced fuel consumption on each road segment to explore the patterns and mechanisms of fuel consumption in the study area. The results not only show the effectiveness of the proposed approaches in estimating fuel consumption/emissions but also indicate their advantages for uncovering the relationships between fuel consumption and vehicles’ activities in road networks. PMID:29561813

Long-term trends of Fluorinated Gas Emissions in Los Angeles, California

NASA Astrophysics Data System (ADS)

Kuwayama, T.; Blake, D. R.; Gupta, P.; Gallagher, G.; Herner, J.; Vijayan, A.

2016-12-01

Fluorinated gases (F-gases) are highly potent greenhouse gases (GHG) that can significantly influence the global climate. Many of these F-gases are also classified as ozone-depleting substances (ODS) that have been subject to an international phase down under the Montreal Protocol. While ODS emissions have been regulated at the national and international level, California is the first state that has implemented a number of programs under the auspices of the Global Warming Solutions Act of 2006 (Assembly Bill 32 or AB 32) to limit the emissions of ODS substitutes, specifically hydrofluorocarbons (HFC), which are high global warming and the fastest growing GHGs globally. Many of these California programs are being adopted nationally. This study evaluates the real-world emission trends of major F-gas categories (Class I ODS, Class II ODS, and ODS substitutes) between 2007-08 and 2014-16 in Los Angeles, California. The study utilized rigorous ambient measurements of select F-gases at the Mt. Wilson monitoring station, which provided an ideal site to study the well-mixed urban emissions from the entire Los Angeles Air Basin, and integrated it with regional CO emissions data to estimate the top-down F-gas emissions from the region. The resulting dataset was compared against the bottom-up F-gas emissions inventory published by the California Air Resources Board, and was analyzed to study the long-term trends in the regional F-gas emissions. The results summarized in this manuscript provide insight into the effectiveness of the California's regulatory efforts in reducing F-gas emissions.

Biodiversity matters in feedbacks between climate change and air quality: a study using an individual-based model.

PubMed

Wang, Bin; Shuman, Jacquelyn; Shugart, Herman H; Lerdau, Manuel T

2018-03-30

Air quality is closely associated with climate change via the biosphere because plants release large quantities of volatile organic compounds (VOC) that mediate both gaseous pollutants and aerosol dynamics. Earlier studies, which considered only leaf physiology and simply scale up from leaf-level enhancements of emissions, suggest that climate warming enhances whole forest VOC emissions, and these increased VOC emissions aggravate ozone pollution and secondary organic aerosol formation. Using an individual-based forest VOC emissions model, UVAFME-VOC, that simulates system-level emissions by explicitly simulating forest community dynamics to the individual tree level, ecological competition among the individuals of differing size and age, and radiative transfer and leaf function through the canopy, we find that climate warming only sometimes stimulates isoprene emissions (the single largest source of non-methane hydrocarbon) in a southeastern U.S. forest. These complex patterns result from the combination of higher temperatures' stimulating emissions at the leaf level but decreasing the abundance of isoprene-emitting taxa at the community level by causing a decline in the abundance of isoprene-emitting species (Quercus spp.). This ecological effect eventually outweighs the physiological one, thus reducing overall emissions. Such reduced emissions have far-reaching implications for the climate-air-quality relationships that have been established on the paradigm of warming-enhancement VOC emissions from vegetation. This local scale modeling study suggests that community ecology rather than only individual physiology should be integrated into future studies of biosphere-climate-chemistry interactions. © 2018 by the Ecological Society of America.

Estimating Vehicle Fuel Consumption and Emissions Using GPS Big Data.

PubMed

Kan, Zihan; Tang, Luliang; Kwan, Mei-Po; Zhang, Xia

2018-03-21

The energy consumption and emissions from vehicles adversely affect human health and urban sustainability. Analysis of GPS big data collected from vehicles can provide useful insights about the quantity and distribution of such energy consumption and emissions. Previous studies, which estimated fuel consumption/emissions from traffic based on GPS sampled data, have not sufficiently considered vehicle activities and may have led to erroneous estimations. By adopting the analytical construct of the space-time path in time geography, this study proposes methods that more accurately estimate and visualize vehicle energy consumption/emissions based on analysis of vehicles' mobile activities ( MA ) and stationary activities ( SA ). First, we build space-time paths of individual vehicles, extract moving parameters, and identify MA and SA from each space-time path segment (STPS). Then we present an N-Dimensional framework for estimating and visualizing fuel consumption/emissions. For each STPS, fuel consumption, hot emissions, and cold start emissions are estimated based on activity type, i.e., MA , SA with engine-on and SA with engine-off. In the case study, fuel consumption and emissions of a single vehicle and a road network are estimated and visualized with GPS data. The estimation accuracy of the proposed approach is 88.6%. We also analyze the types of activities that produced fuel consumption on each road segment to explore the patterns and mechanisms of fuel consumption in the study area. The results not only show the effectiveness of the proposed approaches in estimating fuel consumption/emissions but also indicate their advantages for uncovering the relationships between fuel consumption and vehicles' activities in road networks.

Estimation of River Towboat Air Pollution in Saint Louis, Missouri

DOT National Transportation Integrated Search

1976-02-01

The study gives an estimate of river towboat air pollution emissions for the St. Louis Air Pollution Study area. No emissions from secondary sources or from recreational boating on the river of other areas are considered. The emission estimate is bas...

PARTICLE SPECIATION AND EMISSION PROFILES OF SMALL 2-STROKE ENGINES

EPA Science Inventory

The Human Exposure and Atmospheric Sciences Division (HEASD) conducts studies designed to acquire information from emission sources for use in source apportionment studies. The objective of this work is to characterize a complete, speciated emission profile (PM and air toxics) ...

Real-World Vehicle Emissions: A Summary of the 18th Coordinating Research Council On-Road Vehicle Emissions Workshop

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cadle, S. H.; Ayala, A.; Black, K. N.

2009-02-01

The Coordinating Research Council (CRC) convened its 18th On-Road Vehicle Emissions Workshop March 31-April 2, 2008, with 104 presentations describing the most recent mobile source-related emissions research. In this paper we summarize the presentations from researchers whose efforts are improving our understanding of the contribution of mobile sources to air quality. Participants in the workshop discussed emission models and emissions inventories, results from gas- and particle-phase emissions studies from spark-ignition and diesel-powered vehicles (with an emphasis in this workshop on particle emissions), effects of fuels on emissions, evaluation of in-use emission-control programs, and efforts to improve our capabilities in performingmore » on-board emissions measurements, as well as topics for future research.« less

CHARACTERIZATION OF EMISSIONS FROM BURNING INCENSE

EPA Science Inventory

The primary objective of this study was to improve the characterization of particulate matter emissions from burning incense. Emissions of particulate matter were measured for 23 different types of incense using a cyclone/filter method. Emission rates for PM2.5 (particulate matte...

Determining residential energy consumption-based CO2 emissions and examining the factors affecting the variation in Ankara, Turkey

NASA Astrophysics Data System (ADS)

Kus, Melike; Akan, Perihan; Aydinalp Koksal, Merih; Gullu, Gulen

2017-11-01

Energy demand of Turkey has been showing a remarkable increase in the last two decades due to rapid increase in population and changes in consumption trends. In parallel to the increase in energy demand, the CO2 emissions in Turkey are also increasing dramatically due to high usage of fossil fuels. CO2 emissions from the residential sector covers almost one fourth of the total sectoral emissions. In this study, CO2 emissions from the residential sector are estimated, and the factors affecting the emission levels are determined for the residential sector in Ankara, Turkey. In this study, detailed surveys are conducted to more than 400 households in Ankara. Using the information gathered from the surveys, the CO2 emissions associated with energy consumption of the households are calculated using the methodology outlined at IPCC. The statistical analyses are carried out using household income, dwelling characteristics, and household economic and demographic data to determine the factors causing the variation in emission levels among the households. The results of the study present that the main factors impacting the amount of total energy consumption and associated CO2 emissions are household income, dwelling construction year, age, education level of the household, and net footage of the dwelling.

Urban energy consumption and related carbon emission estimation: a study at the sector scale

NASA Astrophysics Data System (ADS)

Lu, Weiwei; Chen, Chen; Su, Meirong; Chen, Bin; Cai, Yanpeng; Xing, Tao

2013-12-01

With rapid economic development and energy consumption growth, China has become the largest energy consumer in the world. Impelled by extensive international concern, there is an urgent need to analyze the characteristics of energy consumption and related carbon emission, with the objective of saving energy, reducing carbon emission, and lessening environmental impact. Focusing on urban ecosystems, the biggest energy consumer, a method for estimating energy consumption and related carbon emission was established at the urban sector scale in this paper. Based on data for 1996-2010, the proposed method was applied to Beijing in a case study to analyze the consumption of different energy resources (i.e., coal, oil, gas, and electricity) and related carbon emission in different sectors (i.e., agriculture, industry, construction, transportation, household, and service sectors). The results showed that coal and oil contributed most to energy consumption and carbon emission among different energy resources during the study period, while the industrial sector consumed the most energy and emitted the most carbon among different sectors. Suggestions were put forward for energy conservation and emission reduction in Beijing. The analysis of energy consumption and related carbon emission at the sector scale is helpful for practical energy saving and emission reduction in urban ecosystems.

Scanned-probe field-emission studies of vertically aligned carbon nanofibers

NASA Astrophysics Data System (ADS)

Merkulov, Vladimir I.; Lowndes, Douglas H.; Baylor, Larry R.

2001-02-01

Field emission properties of dense and sparse "forests" of randomly placed, vertically aligned carbon nanofibers (VACNFs) were studied using a scanned probe with a small tip diameter of ˜1 μm. The probe was scanned in directions perpendicular and parallel to the sample plane, which allowed for measuring not only the emission turn-on field at fixed locations but also the emission site density over large surface areas. The results show that dense forests of VACNFs are not good field emitters as they require high extracting (turn-on) fields. This is attributed to the screening of the local electric field by the neighboring VACNFs. In contrast, sparse forests of VACNFs exhibit moderate-to-low turn-on fields as well as high emission site and current densities, and long emission lifetime, which makes them very promising for various field emission applications.

Airport emissions quantification: Impacts of electrification. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Geba, V.

1998-07-01

Four airports were assessed to demonstrate that electrification of economically viable air- and land-side vehicles and equipment can significantly reduce total airport emissions. Assessments were made using the FAA`s Emissions and Dispersion Modeling System and EPRI Airport Electrification Project data. Development and implementation of cost-effective airport emissions reduction strategies can be complex, requiring successful collaboration of local, state, and federal regulatory agencies with airport authorities. The methodology developed in this study helps to simplify this task. The objectives of this study were: to develop a methodology to quantify annual emissions at US airports from all sources--aircraft, vehicles, and infrastructure; andmore » to demonstrate that electrification of economically viable air- and land-side vehicles and equipment can significantly reduce total airport emissions on-site, even when allowing for emissions from the generation of electricity.« less

Environment, Health and Climate: Impact of African aerosols

NASA Astrophysics Data System (ADS)

Liousse, C.; Doumbia, T.; Assamoi, E.; Galy-Lacaux, C.; Baeza, A.; Penner, J. E.; Val, S.; Cachier, H.; Xu, L.; Criqui, P.

2012-12-01

Fossil fuel and biofuel emissions of particles in Africa are expected to significantly increase in the near future, particularly due to rapid growth of African cities. In addition to biomass burning emissions prevailing in these areas, air quality degradation is then expected with important consequences on population health and climatic/radiative impact. In our group, we are constructing a new integrated methodology to study the relations between emissions, air quality and their impacts. This approach includes: (1) African combustion emission characterizations; (2) joint experimental determination of aerosol chemistry from ultrafine to coarse fractions and health issues (toxicology and epidemiology). (3) integrated environmental, health and radiative modeling. In this work, we show some results illustrating our first estimates of African anthropogenic emission impacts: - a new African anthropogenic emission inventory adapted to regional specificities on traffic, biofuel and industrial emissions has been constructed for the years 2005 and 2030. Biomass burning inventories were also improved in the frame of AMMA (African Monsoon) program. - carbonaceous aerosol radiative impact in Africa has been modeled with TM5 model and Penner et al. (2011) radiative code for these inventories for 2005 and 2030 and for two scenarios of emissions : a reference scenario, with no further emission controls beyond those achieved in 2003 and a ccc* scenario including planned policies in Kyoto protocol and regulations as applied to African emission specificities. In this study we will show that enhanced heating is expected with the ccc* scenarios emissions in which the OC fraction is relatively lower than in the reference scenario. - results of short term POLCA intensive campaigns in Bamako and Dakar in terms of aerosol chemical characterization linked to specific emissions sources and their inflammatory impacts on the respiratory tract through in vitro studies. In this study, organic carbon particles have appeared quite biologically active. Quite importantly, air quality improvement obtained through regulations in the ccc* scenario are accompanied by stronger heating impact.

Assessment of discrepancies between bottom-up and regional emission inventories in Norwegian urban areas

NASA Astrophysics Data System (ADS)

López-Aparicio, Susana; Guevara, Marc; Thunis, Philippe; Cuvelier, Kees; Tarrasón, Leonor

2017-04-01

This study shows the capabilities of a benchmarking system to identify inconsistencies in emission inventories, and to evaluate the reason behind discrepancies as a mean to improve both bottom-up and downscaled emission inventories. Fine scale bottom-up emission inventories for seven urban areas in Norway are compared with three regional emission inventories, EC4MACS, TNO_MACC-II and TNO_MACC-III, downscaled to the same areas. The comparison shows discrepancies in nitrogen oxides (NOx) and particulate matter (PM2.5 and PM10) when evaluating both total and sectorial emissions. The three regional emission inventories underestimate NOx and PM10 traffic emissions by approximately 20-80% and 50-90%, respectively. The main reasons for the underestimation of PM10 emissions from traffic in the regional inventories are related to non-exhaust emissions due to resuspension, which are included in the bottom-up emission inventories but are missing in the official national emissions, and therefore in the downscaled regional inventories. The benchmarking indicates that the most probable reason behind the underestimation of NOx traffic emissions by the regional inventories is the activity data. The fine scale NOx traffic emissions from bottom-up inventories are based on the actual traffic volume at the road link and are much higher than the NOx emissions downscaled from national estimates based on fuel sales and based on population for the urban areas. We have identified important discrepancies in PM2.5 emissions from wood burning for residential heating among all the inventories. These discrepancies are associated with the assumptions made for the allocation of emissions. In the EC4MACs inventory, such assumptions imply high underestimation of PM2.5 emissions from the residential combustion sector in urban areas, which ranges from 40 to 90% compared with the bottom-up inventories. The study shows that in three of the seven Norwegian cities there is need for further improvement of the emission inventories.

Future anthropogenic pollutant emissions in a Mediterranean port city with emphasis on the maritime sector emissions - Study of the impact on the city air quality

NASA Astrophysics Data System (ADS)

Liora, Natalia; Poupkou, Anastasia; Markakis, Konstantinos; Giannaros, Theodoros; Karagiannidis, Athanasios; Melas, Dimitrios

2013-04-01

The aim of this study is the estimation of the future emissions in the area of the large urban center of Thessaloniki (Greece) with emphasis on the emissions originated from the maritime sector within the port area of the city which are presented in detail. In addition, the contribution of the future anthropogenic emissions to atmospheric pollution levels in Thessaloniki focusing on PM levels is studied. A 2km spatial resolution anthropogenic gaseous and particulate matter emission inventory has been compiled for the port city of Thessaloniki for the year 2010 with the anthropogenic emission model MOSESS, developed by Laboratory of Atmospheric Physics of the Aristotle University of Thessaloniki. MOSESS was used for the estimation of emissions from several emission sources (road transport, central heating, industries, maritime sector etc) while the natural emission model NEMO was implemented for the calculation of dust, sea salt and biogenic emissions. Maritime emissions originated from the various processes inside the area of the port (harbor operations such as stockpiles, loading/unloading operations, machineries etc) as well as from the maritime transport sector including passenger ships, cargo shipping, inland waterways vessels (e.g. pleasure crafts) and fish catching ships. Ship emissions were estimated for the three operation modes; cruising, maneuvering and hotelling. For the calculation of maritime emissions, the activity data used were provided by local and national authorities (e.g.Thessaloniki Port Authority S.A.). Pollutant anthropogenic emissions were projected to the year 2020. The emissions from all the anthropogenic sources except for the maritime sector were projected using factors provided by the GAINS model. Future emissions from the maritime activities were estimated on the basis of the future activity data provided by the Port Authority and of the legislation for shipping in the future. Future maritime emissions are determined by the vessels traffic changes as foreseen for the year 2020 by the Port Authority Investment Plan and by the reduction of the sulfur content in fuels used by ships in cruising mode to 0.5% m/m according to a revision of the MARPOL Annex VI. Based on the above, an approximately 60% increase in the future maritime sector PM10 emissions is expected due to the high increase of the traffic of vessels. The impact of future emissions on the air quality of Thessaloniki is examined with the use of the modelling system WRF-CAMx applied with 2km spatial resolution over the study area. Simulations of the modelling system are performed for a summertime (July 2011) and a wintertime (15 November to 15 December 2011) period accounting for present time (scenario A) and future time (scenario B) pollutant emissions. The differences in pollutant levels (mainly PM) between the scenarios examined are presented and discussed.

Unregulated emissions from compressed natural gas (CNG) transit buses configured with and without oxidation catalyst.

PubMed

Okamoto, Robert A; Kado, Norman Y; Kuzmicky, Paul A; Ayala, Alberto; Kobayashi, Reiko

2006-01-01

The unregulated emissions from two in-use heavy-duty transit buses fueled by compressed natural gas (CNG) and equipped with oxidation catalyst (OxiCat) control were evaluated. We tested emissions from a transit bus powered by a 2001 Cummins Westport C Gas Plus 8.3-L engine (CWest), which meets the California Air Resources Board's (CARB) 2002 optional NOx standard (2.0 g/bhp-hr). In California, this engine is certified only with an OxiCat, so our study did not include emissions testing without it. We also tested a 2000 New Flyer 40-passenger low-floor bus powered by a Detroit Diesel series 50G engine (DDCs50G) that is currently certified in California without an OxiCat. The original equipment manufacturer (OEM) offers a "low-emission" package for this bus that includes an OxiCat for transit bus applications, thus, this configuration was also tested in this study. Previously, we reported that formaldehyde and other volatile organic emissions detected in the exhaust of the DDCs50G bus equipped with an OxiCat were significantly reduced relative to the same DDCs50G bus without OxiCat. In this paper, we examine othertoxic unregulated emissions of significance. The specific mutagenic activity of emission sample extracts was examined using the microsuspension assay. The total mutagenic activity of emissions (activity per mile) from the OxiCat-equipped DDC bus was generally lower than that from the DDC bus without the OxiCat. The CWest bus emission samples had mutagenic activity that was comparable to that of the OxiCat-equipped DDC bus. In general, polycyclic aromatic hydrocarbon (PAH) emissions were lower forthe OxiCat-equipped buses, with greater reductions observed for the volatile and semivolatile PAH emissions. Elemental carbon (EC) was detected in the exhaust from the all three bus configurations, and we found that the total carbon (TC) composition of particulate matter (PM) emissions was primarily organic carbon (OC). The amount of carbon emissions far exceeded the PM-associated inorganic element emissions, which were detected in all exhaust samples, at comparatively small emission rates. In summary, based on these results and those referenced from our group, the use of OxiCat for the new CWest engine and as a retrofit option for the DDCs50G engine generally results in the reduction of tailpipe toxic emissions. However, the conclusions of this study do not take into account OxiCat durability, deterioration, lubricant consumption, or vehicle maintenance, and these parameters merit further study.

USCG Pollution Abatement Program : A Preliminary Study of Vessel and Boat Exhaust Emissions

DOT National Transportation Integrated Search

1971-11-30

A preliminary study of exhaust emissions from Coast Guard vessels and boats indicates that the Coast Guard fleet is an insignificant contributor to air pollution on a national and regional basis. Based upon fuel usage data, emission estimates by vess...

Cold Temperature Effects on Speciated VOC Emissions from modern GDI Light Duty Truck

EPA Science Inventory

Although gasoline direct injection (GDI) vehicles represent nearly half of the light-duty vehicle market share, few studies have reported speciated volatile organic compounds (VOCs) in GDI vehicle exhaust emissions. In this study, speciated VOC emissions were characterized from t...

Construction activity, emissions, and air quality impacts : real-world observations from an Arizona road-widening case study.

DOT National Transportation Integrated Search

2010-10-22

The Arizona Department of Transportation (ADOT) sponsored this investigation, a field : study of emissions and air quality impacts generated from a road widening project, to gain : insight into construction-related emissions of particulate matter (PM...

COLD TEMPERATURE MOTOR VEHICLE EMISSIONS TESTING IN ALASKA

EPA Science Inventory

A motor vehicle emissions testing study was conducted in Anchorage and Fairbanks during the winter of 1998-99 to collect actual measurements of initial idle emission rates. The study was performed for a sample of 111 automobiles and light-duty trucks under cold wintertime ambient...

REGIONAL AIR POLLUTION STUDY: HEAT EMISSION INVENTORY

EPA Science Inventory

As part of the St. Louis Regional Air Pollution Study (RAPS), a heat emission inventory has been assembled. Heat emissions to the atmosphere originate, directly or indirectly, from the combustion of fossil fuels (there are no nuclear plants in the St. Louis AQCR). With the except...

Model study of greenline dayglow emission under geomagnetic storm conditions.

NASA Astrophysics Data System (ADS)

Singh, V.; Bag, T.; Sunil Krishna, M. V.

2016-12-01

A comprehensive model is developed to study the influences of geomagnetic storms on greenline (557.7 nm) dayglow emission during the solar active and solar quiet conditions in thermosphere. This study is based on a photochemical model which is developed using the latest reaction rate coefficients, quantum yields and collisional cross-sections obtained from the experimental observations and empirical models. This study is for a low latitude station Tirunelveli (8.7N,77.8E), India. The volume emission rate (VER) has been calculated using the densities and temperature from NRLMSISE-00 and IRI-2012 models. The modeled VER shows a positive correlation with the Dst index, and a negative correlation with the number densities of O, O2, and N2. The VER calculated at the peak emission altitude shows depletion during the main phase of the storm. The peak emission altitude doesn't show any appreciable variation during storm period. On the other hand, the peak emission altitude shows an upward movement with the increase in F10.7 solar index.

An AIS-based high-resolution ship emission inventory and its uncertainty in Pearl River Delta region, China.

PubMed

Li, Cheng; Yuan, Zibing; Ou, Jiamin; Fan, Xiaoli; Ye, Siqi; Xiao, Teng; Shi, Yuqi; Huang, Zhijiong; Ng, Simon K W; Zhong, Zhuangmin; Zheng, Junyu

2016-12-15

Ship emissions contribute significantly to air pollution and impose health risks to residents along the coastal area. By using the refined data from the Automatic Identification System (AIS), this study developed a highly resolved ship emission inventory for the Pearl River Delta (PRD) region, China, home to three of ten busiest ports in the world. The region-wide SO 2 , NO X , CO, PM 10 , PM 2.5 , and VOC emissions in 2013 were estimated to be 61,484, 103,717, 10,599, 7155, 6605, and 4195t, respectively. Ocean going vessels were the largest contributors of the total emissions, followed by coastal vessels and river vessels. In terms of ship type, container ship was the leading contributor, followed by conventional cargo ship, dry bulk carrier, fishing ship, and oil tanker. These five ship types accounted for >90% of total emissions. The spatial distributions of emissions revealed that the key emission hot spots all concentrated within the newly proposed emission control area (ECA) and ship emissions within ECA covered >80% of total ship emissions in the PRD, highlighting the importance of ECA in emissions reduction in the PRD. The uncertainties of emission estimates of pollutants were quantified, with lower bounds of -24.5% to -21.2% and upper bounds of 28.6% to 33.3% at 95% confidence intervals. The lower uncertainties in this study highlighted the powerfulness of AIS data in improving ship emission estimates. The AIS-based bottom-up methodology can be used for developing and upgrading ship emission inventory and formulating effective control measures on ship emissions in other port regions wherever possible. Copyright © 2016 Elsevier B.V. All rights reserved.

Projections of NH3 emissions from manure generated by livestock production in China to 2030 under six mitigation scenarios.

PubMed

Xu, Peng; Koloutsou-Vakakis, Sotiria; Rood, Mark J; Luan, Shengji

2017-12-31

China's rapid urbanization, large population, and increasing consumption of calorie-and meat-intensive diets, have resulted in China becoming the world's largest source of ammonia (NH 3 ) emissions from livestock production. This is the first study to use provincial, condition-specific emission factors based on most recently available studies on Chinese manure management and environmental conditions. The estimated NH 3 emission temporal trends and spatial patterns are interpreted in relation to government policies affecting livestock production. Scenario analysis is used to project emissions and estimate mitigation potential of NH 3 emissions, to year 2030. We produce a 1km×1km gridded NH 3 emission inventory for 2008 based on county-level activity data, which can help identify locations of highest NH 3 emissions. The total NH 3 emissions from manure generated by livestock production in 2008 were 7.3TgNH 3 ·yr -1 (interquartile range from 6.1 to 8.6TgNH 3 ·yr -1 ), and the major sources were poultry (29.9%), pigs (28.4%), other cattle (27.9%), and dairy cattle (7.0%), while sheep and goats (3.6%), donkeys (1.3%), horses (1.2%), and mules (0.7%) had smaller contributions. From 1978 to 2008, annual NH 3 emissions fluctuated with two peaks (1996 and 2006), and total emissions increased from 2.2 to 7.3Tg·yr -1 increasing on average 4.4%·yr -1 . Under a business-as-usual (BAU) scenario, NH 3 emissions in 2030 are expected to be 13.9TgNH 3 ·yr -1 (11.5-16.3TgNH 3 ·yr -1 ). Under mitigation scenarios, the projected emissions could be reduced by 18.9-37.3% compared to 2030 BAU emissions. This study improves our understanding of NH 3 emissions from livestock production, which is needed to guide stakeholders and policymakers to make well informed mitigation decisions for NH 3 emissions from livestock production at the country and regional levels. Copyright © 2017 Elsevier B.V. All rights reserved.

The Another Assimilation System for WRF-Chem (AAS4WRF): a new mass-conserving emissions pre-processor for WRF-Chem regional modelling

NASA Astrophysics Data System (ADS)

Vara Vela, A. L.; Muñoz, A.; Lomas, A., Sr.; González, C. M.; Calderon, M. G.; Andrade, M. D. F.

2017-12-01

The Weather Research and Forecasting with Chemistry (WRF-Chem) community model have been widely used for the study of pollutants transport, formation of secondary pollutants, as well as for the assessment of air quality policies implementation. A key factor to improve the WRF-Chem air quality simulations over urban areas is the representation of anthropogenic emission sources. There are several tools that are available to assist users in creating their own emissions based on global emissions information (e.g. anthro_emiss, prep_chem_src); however, there is no single tool that will construct local emissions input datasets for any particular domain at this time. Because the official emissions pre-processor (emiss_v03) is designed to work with domains located over North America, this work presents the Another Assimilation System for WRF-Chem (AAS4WRF), a ncl based mass-conserving emissions pre-processor designed to create WRF-Chem ready emissions files from local inventories on a lat/lon projection. AAS4WRF is appropriate to scale emission rates from both surface and elevated sources, providing the users an alternative way to assimilate their emissions to WRF-Chem. Since it was successfully tested for the first time for the city of Lima, Peru in 2014 (managed by SENAMHI, the National Weather Service of the country), several studies on air quality modelling have applied this utility to convert their emissions to those required for WRF-Chem. Two case studies performed in the metropolitan areas of Sao Paulo and Manizales in Brazil and Colombia, respectively, are here presented in order to analyse the influence of using local or global emission inventories in the representation of regulated air pollutants such as O3 and PM2.5. Although AAS4WRF works with local emissions information at the moment, further work is being conducted to make it compatible with global/regional emissions data file format. The tool is freely available upon request to the corresponding author.

Economic growth and carbon emission control

NASA Astrophysics Data System (ADS)

Zhang, Zhenyu

The question about whether environmental improvement is compatible with continued economic growth remains unclear and requires further study in a specific context. This study intends to provide insight on the potential for carbon emissions control in the absence of international agreement, and connect the empirical analysis with theoretical framework. The Chinese electricity generation sector is used as a case study to demonstrate the problem. Both social planner and private problems are examined to derive the conditions that define the optimal level of production and pollution. The private problem will be demonstrated under the emission regulation using an emission tax, an input tax and an abatement subsidy respectively. The social optimal emission flow is imposed into the private problem. To provide tractable analytical results, a Cobb-Douglas type production function is used to describe the joint production process of the desired output and undesired output (i.e., electricity and emissions). A modified Hamiltonian approach is employed to solve the system and the steady state solutions are examined for policy implications. The theoretical analysis suggests that the ratio of emissions to desired output (refer to 'emission factor'), is a function of productive capital and other parameters. The finding of non-constant emission factor shows that reducing emissions without further cutting back the production of desired outputs is feasible under some circumstances. Rather than an ad hoc specification, the optimal conditions derived from our theoretical framework are used to examine the relationship between desired output and emission level. Data comes from the China Statistical Yearbook and China Electric Power Yearbook and provincial information of electricity generation for the year of 1993-2003 are used to estimate the Cobb-Douglas type joint production by the full information maximum likelihood (FIML) method. The empirical analysis shed light on the optimal policies of emissions control required for achieving the social goal in a private context. The results suggest that the efficiency of abatement technology is crucial for the timing of executing the emission tax. And emission tax is preferred to an input tax, as long as the detection of emissions is not costly and abatement technology is efficient. Keywords: Economic growth, Carbon emission, Power generation, Joint production, China

Characterization of in-use emissions from TxDOT's non-road equipment fleet : phase 1 report.

DOT National Transportation Integrated Search

2009-06-01

The objective of this document is to present the preliminary findings of the study characterizing in-use : TxDOT non-road diesel equipment emissions. This document presents literature reviews of emissions : reduction technologies and emissions contro...

Comparisons between vehicular emissions from real-world in-use testing and EPA moves estimation.

DOT National Transportation Integrated Search

2012-07-01

"This research study developed a methodology to perform mandatory dynamometer vehicular emissions tests : on real roads, performed on-road emissions tests, and compared the test results to the estimates using the : current EPA emissions estimation mo...

Emissions estimates of carbon tetrachloride for 1992-2014 in China.

PubMed

Bie, Pengju; Fang, Xuekun; Li, Zhifang; Wang, Ziyuan; Hu, Jianxin

2017-05-01

Discrepancies in emission estimates of carbon tetrachloride (CCl 4 , CTC), between bottom-up and top-down methods, have been shown since the 1990s at both the global and regional scale. This study estimates the emissions of China from 1992 to 2014 based on emission functions and aggregated activity information given reasonable uncertainties. The results show that emissions increase from 7.3 Gg/yr (5.6-9.1 Gg/yr at 95% confidential interval) to 14.0 (9.1-19.5) Gg/yr with a growth rate of 6.7 (1.9-11.4) %/yr during 1992-2002 and then decrease to a minimum of 4.3 (1.9-8.0) Gg/yr in 2011. More than 54% of the emissions during 1992-2009 are from the process agents sector. The estimates are comparable with those of other studies and those in this study based on observations during 2011-2014 using the interspecies correlation method. China's contribution to global emissions increases from 7.5% to 19.5% during 1992-2009, but the contribution is reduced to 9.9% and 8.0% in 2010 and 2011, respectively, indicating the effectiveness of compliance with the Montreal Protocol and its subsequent Amendments and Adjustments, whereby CTC emissions are phased-out. The results of this study are beneficial for narrowing the gap between bottom-up estimates and top-down emission calculations of CTC in China. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of severe geomagnetic disturbances on the atomic oxygen airglow emissions

NASA Astrophysics Data System (ADS)

Sunil Krishna, M.; Bag, T.

2013-12-01

The atomic oxygen greenline (557.7nm) and redline emission (630.0 nm) are the most readily observed and prominent lines in the nightglow. These emissions can be used as precursors for a variety of physical and chemical processes that occur in the upper mesosphere and lower thermosphere. There are a multitude of effects of space weather on the Earth's atmosphere. The decay of ring current is a very important parameter which can induce variation in the densities of few important species in the atmosphere which are of airglow interest. The connection of variation of airglow emissions with the extreme space weather conditions is not very well established. In the present study, severe geomagnetic storms and their effect on the airglow emissions such as 557.7 nm and 630.0 nm emissions is studied. This study is primarily based on photochemical models with the necessary input obtained from a combination of experimental observations and empirical models. We have tried to understand the effect of severe space weather conditions on few very important airglow emissions in terms of volume emission rates, change in the peak emission height. Based on the variation an attempt has been made to understand the cause of the variation and further to link the variations in the ring current to the airglow chemistry. The study presents the results of calculations performed for the most severe geomagnetic storms occurred over the recent past because of variety of causes on Sun.

Application rate affects the degradation rate and hence emissions of chloropicrin in soil.

PubMed

Ashworth, Daniel J; Yates, Scott R; Stanghellini, Mike; van Wesenbeeck, Ian J

2018-05-01

Increasingly stringent regulations to control soil-air emissions of soil fumigants has led to much research effort aimed at reducing emission potential. Using laboratory soil columns, we aimed to investigate the relationship between chloropicrin (CP) application rate and its emissions from soil across a wide range of CP applications (equivalent to 56-392kgha -1 ). In contrast to the known behavior of other fumigants, total emission percentages were strongly and positively related to application rate (i.e., initial mass), ranging from 4 to 34% across the application rate range. When combined, data from a previous study and the present study showed good overall comparability in terms of CP application rate vs. emission percentage, yielding a second-order polynomial relationship with an R 2 value of 0.93 (n=12). The study revealed that mass losses of CP were strongly disproportional to application rate, also showing a polynomial relationship. Based on degradation studies, we consider that a shorter half-life (faster degradation) at lower application rates limited the amount of CP available for emission. The non-linear relationship between CP application rate and CP emissions (both as % of that applied and as total mass) suggests that low application rates likely lead to disproportionally low emission losses compared with higher application rates; such a relationship could be taken into account when assessing/mitigating risk, e.g., in the setting of buffer zone distances. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of Drought Stress and Ozone Exposure on Isoprene Emissions from Oak Seedlings in Texas

NASA Astrophysics Data System (ADS)

Madronich, M. B.; Harte, A.; Schade, G. W.

2014-12-01

Isoprene is the dominant hydrocarbon emitted by plants to the atmosphere with an approximate global emission of 550 Tg C yr-1. Isoprene emission studies have elucidated plants' isoprene production capacity, and the controlling factors of instantaneous emissions. However, it is not yet well understood how long-term climatic factors such as drought and increasing ozone concentrations affect isoprene emission rates. Drought reduces photosynthetic activity and is thus expected to reduce isoprene emission rate, since isoprene production relies on photosynthates. On the other hand, ozone is also known to negatively affect photosynthesis rates, but can instead increase isoprene emissions. These apparent inconsistencies and a lack of experimental data make it difficult to accurately parameterize isoprene emission responses to changing environmental conditions. The objective of this work is to reduce some of these uncertainties, using oak seedlings as a study system. Our project focuses on isoprene emission responses of oak trees to typical summer drought and high ozone conditions in Texas. We report on experiments conducted using a laboratory whole-plant chamber and leaf-level data obtained from greenhouse-grown seedlings. The chamber experiment studied the effects of ozone and drought on isoprene emissions from >3 year old oak seedlings under controlled conditions of photosynthetically active radiation (PAR), temperature, soil-moisture and the chamber's air composition. Stress in plants was induced by manipulating potted soil-moisture and ozone concentration in the chamber. The greenhouse study focused on understanding the effects of drought under Texas climatic conditions. For this study we used two year old seedlings of water oak (Quercus nigra) and post oak (Quercus stellata). Temperature, humidity and light in the greenhouse followed local conditions. Leaf-level conductance, photosynthesis measurements and isoprene sampling were carried out under controlled leaf temperature and PAR. The only variable manipulated was the water added to the plants. Seedling isoprene and other VOC emissions were identified and quantified using GC-FID techniques. The results of our work may allow for an improved parameterization of isoprene emissions in VOC inventories, particularly for Texas.

Biogenic volatile organic compounds (BVOCs) emissions from Abies alba in a French forest.

PubMed

Moukhtar, S; Couret, C; Rouil, L; Simon, V

2006-02-01

Air quality studies need to be based on accurate and reliable data, particularly in the field of the emissions. Biogenic emissions from forests, crops, and grasslands are now considered as major compounds in photochemical processes. Unfortunately, depending on the type of vegetation, these emissions are not so often reliably defined. As an example, although the silver fir (Abies alba) is a very widespread conifer tree in the French and European areas, its standard emission rate is not available in the literature. This study investigates the isoprene and monoterpenes emission from A. alba in France measured during the fieldwork organised in the Fossé Rhénan, from May to June 2003. A dynamic cuvette method was used. Limonene was the predominant monoterpene emitted, followed by camphene, alpha-pinene and eucalyptol. No isoprene emission was detected. The four monoterpenes measured showed different behaviours according to micrometeorological conditions. In fact, emissions of limonene, alpha-pinene and camphene were temperature-dependant while eucalyptol emissions were temperature and light dependant. Biogenic volatile organic compounds emissions were modeled using information gathered during the field study. Emissions of the three monoterpenes previously quoted were achieved using the monoterpenes algorithm developed by Tingey et al. (1980) [Tingey D, Manning M, Grothaus L, Burns W. Influence of light and temperature on monoterpene emission rates from slash pine. Plant Physiol 1980;65: 797-801.] and the isoprene algorithm [Guenther, A., Monson, R., Fall, R., 1991. Isoprene and monoterpene emission rate variability: observations with eucalyptus and emission rate algorithm development. J Geophys Res 26A: 10799-10808.]; [Guenther, A., Zimmerman, P., Harley, P., Monson, R., Fall, R., 1993. Isoprene and monoterpene emission rate variability: model evaluation and sensitivity analysis. J Geophys Res 98D: 12609-12617.]) was used for the eucalyptol emission. With these methods, simulation results and observations agreed fairly well. The standard emission rate (303 K) and beta-coefficient averaged for limonene, camphene and alpha-pinene were respectively of 0.63 microg gdw-1 h-1 and 0.06 K-1. For eucalyptol, the standard emission rate (T=303 K and PAR=1000 micromol m-2 s-1) was 0.26 microg gdw-1 h-1. This classified A. alba as a weak monoterpenes emitter.

Characteristics of Biogenic VOCs Emission and its High-Resolution Emission Inventory in China

NASA Astrophysics Data System (ADS)

Li, L.; Li, Y.; Xie, S.

2017-12-01

Biogenic volatile organic compounds (BVOCs), with high emission and reactivity, can have substantial impacts on the haze and photochemical pollution. It is essential to establish an accurate high-resolution BVOC emission inventory in China for air quality simulation and decision making. Firstly, a semi-static enclosure technique is developed for the field measurements of BVOC emission rates from 50 plant species in China. Using the GC-MS/FID system, 103 VOC species for each plant species are measured. Based on the field measurements in our study and the reported emission rates at home and abroad, a methodology for determining the emission categories of BVOCs is developed using statistical analysis. The isoprene and monoterpene emission rates of 192 plant species/genera in China are determined based on the above emission categories. Secondly, a new vegetation classification with 82 plant functional types (PFTs) is developed based on the most detailed and latest vegetation investigations, China's official statistical data and Vegetation Atlas of China (1:1,000,000). The leaf biomass is estimated based on provincial vegetation volume and production with biomass-apportion models. The WRF model is used to determine meteorological variables at a high spatio-temporal resolution. Using MEAGNv2.1 and the determined emission rates in our study, the high-resolution emission inventories of isoprene, 37 monoterpene species, 32 sesquiterpene species, and other VOCs (OVOCs) from 82 PFTs in China for 1981-2013 are established. The total annual BVOC emissions in 2013 are 55.88 Tg, including 33.87 Tg isoprene, 6.36 Tg monoterpene, 1.29 Tg sesquiterpene, and 14.37 Tg OVOCs. The distribution of isoprene emission fluxes is consistent with the distribution of broadleaf trees, especially tree species with high or higher emission potential. During 1981-2013, China's BVOC emissions have increased by 47.48% at an average rate of 1.80% yr-1. Emissions of isoprene have the largest enhancement, with an average rate of 3.10% yr-1. The increasing BVOC emissions largely originate from the enhanced forest volume and crop production. But the influence of meteorology cannot be ignored. Our study will be very significant for understanding the BVOC emission characteristics and improving the accuracy of air quality simulation in China.

Quantifying methane emissions from coal and natural gas sources along the northwestern Appalachian

NASA Astrophysics Data System (ADS)

Barkley, Z.; Lauvaux, T.; Davis, K. J.; Fried, A.

2017-12-01

According to the EPA's 2012 gridded inventory (Maasakkers et al., 2016), more than 10% of all CH4 emissions in the U.S. are located along the western edge of the Appalachian with the majority of these emissions coming from natural gas infrastructure and coal mines. However, top-down studies of unconventional wells in southwestern Pennsylvania have found emission rates to be much higher than EPA estimates (Caulton et al., 2014, Ren et al., 2017). Furthermore, although 9 of the 10 largest sources of CH4 in the EPA Greenhouse Gas Reporting Program are coal mines located in this region, no top down studies have been performed to assess the accuracy of these enormous point sources. This study uses aircraft data from the ACT-America flight campaign in conjunction with techniques previously used to solve for CH4 emissions from the northeastern Marcellus (Barkley et al., 2017) to quantify the total CH4 flux from the western Pennsylvania/West Virginia region and constrain emissions from natural gas and coal with an upper limit for each source. We use the WRF-Chem mesoscale model at 3 km resolution to simulate CH4 enhancements from a customized emissions inventory and compare the modelled enhancements to observations from 7 flights that were downwind of coal and gas sources. Coal and natural gas emissions are adjusted in the model to minimize a cost function that accounts for the difference between the modelled and observed CH4 values, and a range of likely combinations for natural gas and coal emission rates are obtained for each flight. We then overlap this range of likely emission rates across all flights to further limit the range of possible emission rates. Influence functions created using a lagrangian particle dispersion model for segments of each flight provide information on what area emissions are being optimized for. Preliminary results find that CH4 emissions from gas and coal along the northwestern Appalachian are lower than EPA estimates by 20-50%. In particular, upper limits on CH4 emissions from unconventional natural gas are less than 1% of total production, significantly lower than previous top-down estimates in the region. Future work will use ethane data to better distinguish between coal and natural gas emissions, and expand these analyses to other study regions explored in the ACT-America aircraft campaign.

Estimation of carbon dioxide emissions per urban center link unit using data collected by the Advanced Traffic Information System in Daejeon, Korea

NASA Astrophysics Data System (ADS)

Ryu, B. Y.; Jung, H. J.; Bae, S. H.; Choi, C. U.

2013-12-01

CO2 emissions on roads in urban centers substantially affect global warming. It is important to quantify CO2 emissions in terms of the link unit in order to reduce these emissions on the roads. Therefore, in this study, we utilized real-time traffic data and attempted to develop a methodology for estimating CO2 emissions per link unit. Because of the recent development of the vehicle-to-infrastructure (V2I) communication technology, data from probe vehicles (PVs) can be collected and speed per link unit can be calculated. Among the existing emission calculation methodologies, mesoscale modeling, which is a representative modeling measurement technique, requires speed and traffic data per link unit. As it is not feasible to install fixed detectors at every link for traffic data collection, in this study, we developed a model for traffic volume estimation by utilizing the number of PVs that can be additionally collected when the PV data are collected. Multiple linear regression and an artificial neural network (ANN) were used for estimating the traffic volume. The independent variables and input data for each model are the number of PVs, travel time index (TTI), the number of lanes, and time slots. The result from the traffic volume estimate model shows that the mean absolute percentage error (MAPE) of the ANN is 18.67%, thus proving that it is more effective. The ANN-based traffic volume estimation served as the basis for the calculation of emissions per link unit. The daily average emissions for Daejeon, where this study was based, were 2210.19 ton/day. By vehicle type, passenger cars accounted for 71.28% of the total emissions. By road, Gyeryongro emitted 125.48 ton/day, accounting for 5.68% of the total emission, the highest percentage of all roads. In terms of emissions per kilometer, Hanbatdaero had the highest emission volume, with 7.26 ton/day/km on average. This study proves that real-time traffic data allow an emissions estimate in terms of the link unit. Furthermore, an analysis of CO2 emissions can support traffic management to make decisions related to the reduction of carbon emissions.

Well-to-Wheels Analysis of Advanced Fuel/Vehicle Systems: A North American Study of Energy Use, Greenhouse Gas Emissions, and Criteria Pollutant Emissions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brinkman, Norman; Wang, Michael; Weber, Trudy

An accurate assessment of future fuel/propulsion system options requires a complete vehicle fuel-cycle analysis, commonly called a well-to-wheels (WTW) analysis. This WTW study analyzes energy use and emissions associated with fuel production (or well-to-tank [WTT]) activities and energy use and emissions associated with vehicle operation (or tank-to-wheels [TTW]) activities.

Mutagenicity of particle emissions from solid fuel cookstoves: A literature review and research perspective.

PubMed

Shen, Guofeng

2017-07-01

Household solid fuel use is a major source of many air pollutants causing severe air pollution and adverse health outcomes. In evaluation of health impacts of household air pollution, it is essential to characterize toxic properties like mutagenicity of residential fuel combustion emissions and exposure assessments. Mutagenicity of emissions from solid fuel cookstoves were analyzed through a literature review. T98 and TA100 strains are two most widely used strains in mutagenic Ames test, and results for these two strains are generally positively correlated though they have different endpoints. Direct and indirect mutagenic activities are positively correlated, and statistically insignificantly different though indirect mutagenic emissions are apparently higher. Mutagenicity emission factors on the basis of fuel energy (MJ) or useful energy delivered (MJd) for solid fuel cookstoves vary in nearly 3 orders of magnitude, ranging from 3.0×10 4 rev./MJd to 1.8×10 7 rev./MJd (or 1.1×10 4 rev./MJ to 4.2×10 6 rev./MJ). Low mutagenic emissions are reported for high efficiency stoves such as a forced-draft one. Mutagenicity emission factors are positively correlated with emissions of PM 2.5 . Relationship between mutagenicity and polycyclic aromatic hydrocarbons (PAHs) emissions is inconsistent among studies as PAHs are minor fractions of toxic organics contributing to the total mutagenicity. Generally, studies on mutagenicity of emissions from household cookstoves are very limited, and future studies are encouraged on mutagenic emissions from different fuel types and household stoves, evaluation of mutagenic activities of both gaseous and particulate emissions, and toxicology and exposure assessments of household air pollution. Copyright © 2017 Elsevier Inc. All rights reserved.

Modeling the trade-off between diet costs and methane emissions: A goal programming approach.

PubMed

Moraes, L E; Fadel, J G; Castillo, A R; Casper, D P; Tricarico, J M; Kebreab, E

2015-08-01

Enteric methane emission is a major greenhouse gas from livestock production systems worldwide. Dietary manipulation may be an effective emission-reduction tool; however, the associated costs may preclude its use as a mitigation strategy. Several studies have identified dietary manipulation strategies for the mitigation of emissions, but studies examining the costs of reducing methane by manipulating diets are scarce. Furthermore, the trade-off between increase in dietary costs and reduction in methane emissions has only been determined for a limited number of production scenarios. The objective of this study was to develop an optimization framework for the joint minimization of dietary costs and methane emissions based on the identification of a set of feasible solutions for various levels of trade-off between emissions and costs. Such a set of solutions was created by the specification of a systematic grid of goal programming weights, enabling the decision maker to choose the solution that achieves the desired trade-off level. Moreover, the model enables the calculation of emission-mitigation costs imputing a trading value for methane emissions. Emission imputed costs can be used in emission-unit trading schemes, such as cap-and-trade policy designs. An application of the model using data from lactating cows from dairies in the California Central Valley is presented to illustrate the use of model-generated results in the identification of optimal diets when reducing emissions. The optimization framework is flexible and can be adapted to jointly minimize diet costs and other potential environmental impacts (e.g., nitrogen excretion). It is also flexible so that dietary costs, feed nutrient composition, and animal nutrient requirements can be altered to accommodate various production systems. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Considerations for acoustic emission monitoring of spherical Kevlar/epoxy composite pressure vessels

NASA Technical Reports Server (NTRS)

Hamstad, M. A.; Patterson, R. G.

1977-01-01

We are continuing to research the applications of acoustic emission testing for predicting burst pressure of filament-wound Kevlar 49/epoxy pressure vessels. This study has focused on three specific areas. The first area involves development of an experimental technique and the proper instrumentation to measure the energy given off by the acoustic emission transducer per acoustic emission burst. The second area concerns the design of a test fixture in which to mount the composite vessel so that the acoustic emission transducers are held against the outer surface of the composite. Included in this study area is the calibration of the entire test setup including couplant, transducer, electronics, and the instrument measuring the energy per burst. In the third and final area of this study, we consider the number, location, and sensitivity of the acoustic emission transducers used for proof testing composite pressure vessels.

Research on effect of emission uniformity on X-band relativistic backward oscillator using conformal PIC code

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Zaigao

2016-07-15

Explosive emission cathodes (EECs) are adopted in relativistic backward wave oscillators (RBWOs) to generate intense relativistic electron beam. The emission uniformity of the EEC can render saturation of the power generation unstable and the output mode impure. However, the direct measurement of the plasma parameters on the cathode surface is quite difficult and there are very few related numerical study reports about this issue. In this paper, a self-developed three-dimensional conformal fully electromagnetic particle in cell code is used to study the effect of emission uniformity on the X-band RBWO; the electron explosive emission model and the field emission modelmore » are both implemented in the same cathode surface, and the local field enhancement factor is also considered in the field emission model. The RBWO with a random nonuniform EEC is thoroughly studied using this code; the simulation results reveal that when the area ratio of cathode surface for electron explosive emission is 80%, the output power is unstable and the output mode is impure. When the annular EEC does not emit electron in the angle range of 30°, the RBWO can also operate normally.« less

Characterization of the emissions impacts of hybrid excavators with a portable emissions measurement system (PEMS)-based methodology.

PubMed

Cao, Tanfeng; Russell, Robert L; Durbin, Thomas D; Cocker, David R; Burnette, Andrew; Calavita, Joseph; Maldonado, Hector; Johnson, Kent C

2018-04-13

Hybrid engine technology is a potentially important strategy for reduction of tailpipe greenhouse gas (GHG) emissions and other pollutants that is now being implemented for off-road construction equipment. The goal of this study was to evaluate the emissions and fuel consumption impacts of electric-hybrid excavators using a Portable Emissions Measurement System (PEMS)-based methodology. In this study, three hybrid and four conventional excavators were studied for both real world activity patterns and tailpipe emissions. Activity data was obtained using engine control module (ECM) and global positioning system (GPS) logged data, coupled with interviews, historical records, and video. This activity data was used to develop a test cycle with seven modes representing different types of excavator work. Emissions data were collected over this test cycle using a PEMS. The results indicated the HB215 hybrid excavator provided a significant reduction in tailpipe carbon dioxide (CO 2 ) emissions (from -13 to -26%), but increased diesel particulate matter (PM) (+26 to +27%) when compared to a similar model conventional excavator over the same duty cycle. Copyright © 2018 Elsevier B.V. All rights reserved.

A perspective on the potential development of environmentally acceptable light-duty diesel vehicles.

PubMed Central

Hammerle, R; Schuetzle, D; Adams, W

1994-01-01

Between 1979 and 1985, an international technical focus was placed upon potential human health effects associated with exposure to diesel emissions. A substantial data base was developed on the composition of diesel emissions; the fate of these emissions in the atmosphere; and the effects of whole particles and their chemical constituents on microorganisms, cells, and animals. Since that time, a number of significant developments have been made in diesel engine technology that require a new look at the future acceptability of introducing significant numbers of light-duty diesel automobiles into the European and American markets. Significant engineering improvements have been made in engine design, catalysts, and traps. As a result, particle emissions and particle associated organic emissions have been reduced by about 10 and 30 times, respectively, during the past 10 years. Research studies to help assess the environmental acceptability of these fuel-efficient engines include the development of an emissions data base for current and advanced diesel engines, the effect of diesel emissions on urban ozone formation and atmospheric particle concentrations, the effect of fuel composition, e.g., lower sulfur and additives on emissions, animal inhalation toxicology studies, and fundamental molecular biology studies. PMID:7529704

Rapid increase in Chloroform (CHCl3) emissions in China

NASA Astrophysics Data System (ADS)

Fang, X.; Park, S.; Saito, T.; Prinn, R. G.; Rigby, M. L.; Li, S.; Ganesan, A.; Yokouchi, Y.; Lunt, M. F.; Gressent, A.

2017-12-01

Large and effective reductions in emissions of long-lived ozone-depleting substance (ODS) have been achieved through the Montreal Protocol, evidenced by the declining atmospheric abundances of many ODS. An important remaining uncertainty concerns the role of short-lived substances, with lifetimes generally under six months. Chloroform (CHCl3), is an important source of stratospheric halogens, but not regulated under the Montreal Protocol. Recent studies show that the Asian summer monsoon could act as a smokestack to pumping emitted air pollutants in East Asia to the stratosphere. Thus, CHCl3 emitted from East Asia becomes very important. In this study, CHCl3 emissions during the period 2007-2015 for China and other East Asian countries were determined using in-situ atmospheric measurements at ground stations and inverse modeling based on backward model simulation. Results show that CHCl3 emissions from China were very stable during 2007-2011 while emissions increased rapidly after that by more than 2 times through 2015. This study reveals that increase in global CHCl3 emission after 2012 can be attributed to the rapid emission increase in China. There is a growing threat to the ozone layer due to rapid increase in CHCl3 emissions in China.

Historical carbon footprinting and implications for sustainability planning: a case study of the Pittsburgh region.

PubMed

Hoesly, Rachel; Blackhurst, Mike; Matthews, H Scott; Miller, Jeffrey F; Maples, Amy; Pettit, Matthew; Izard, Catherine; Fischbeck, Paul

2012-04-17

This study estimates fossil-based CO(2) emissions and energy use from 1900-2000 for Allegheny County, PA. Total energy use and emissions increased from 1900 to 1970, reflecting the significant industrial, economic, and population growth that occurred in Allegheny County. From 1970 to 2000, Allegheny County experienced a 30% decrease in total emissions and energy use from peak values, primarily because of a decline in industrial activity (40% decrease in value added) and the loss of a quarter of its population. Despite these dramatic economic and demographic transitions, per capita emissions remained stable from 1970 to 2000, buoyed by relatively stable or slightly increasing emissions in the commercial and transportation sectors. Allegheny County's history suggests the scale of change needed to achieve local emissions reductions may be significant; given years of major technological, economic, and demographic changes, per capita emissions in 1940 were nearly the same in 2000. Most local governments are planning emissions reductions rates that exceed 1% per year, which deviate significantly from historical trends. Our results suggest additional resources and improved planning paradigms are likely necessary to achieve significant emissions reductions, especially for areas where emissions are still increasing.

Regional on-road vehicle running emissions modeling and evaluation for conventional and alternative vehicle technologies.

PubMed

Frey, H Christopher; Zhai, Haibo; Rouphail, Nagui M

2009-11-01

This study presents a methodology for estimating high-resolution, regional on-road vehicle emissions and the associated reductions in air pollutant emissions from vehicles that utilize alternative fuels or propulsion technologies. The fuels considered are gasoline, diesel, ethanol, biodiesel, compressed natural gas, hydrogen, and electricity. The technologies considered are internal combustion or compression engines, hybrids, fuel cell, and electric. Road link-based emission models are developed using modal fuel use and emission rates applied to facility- and speed-specific driving cycles. For an urban case study, passenger cars were found to be the largest sources of HC, CO, and CO(2) emissions, whereas trucks contributed the largest share of NO(x) emissions. When alternative fuel and propulsion technologies were introduced in the fleet at a modest market penetration level of 27%, their emission reductions were found to be 3-14%. Emissions for all pollutants generally decreased with an increase in the market share of alternative vehicle technologies. Turnover of the light duty fleet to newer Tier 2 vehicles reduced emissions of HC, CO, and NO(x) substantially. However, modest improvements in fuel economy may be offset by VMT growth and reductions in overall average speed.

Low-Latitude ELF Emissions Below 100Hz Observed in Taiwan

NASA Astrophysics Data System (ADS)

Wang, K.; Wang, Y.; Su, H.; Hsu, R.

2005-12-01

ELF antennas have been mounted at the Lulin Observatory (23.47oN, 120.87oE; 2862m) and National Cheng Kung University (23.00oN, 120.22oE, 32m) in Taiwan for study of global lightning activities and ELF events. We have previously reported 10-month ELF-Whistlers observations from Aug. 26, 2003 to July 13, 2004. [Wang et al., 2005]. In addition to these events, other forms of ELF emissions were also detected. In this study, an Atlas of these observed ELF emissions below 100Hz for the same period of observation is presented. Total numbers of more than 100 detected events are categorized into six groups: discrete emissions, periodic emissions, quasi-periodic emissions, hiss, chorus, and triggered emissions, according to the system of classification for VLF emissions in [Helliwell, 1965]. Nevertheless, there are still some emissions hardly to be classified. Diurnal and seasonal variations of occurrences for these ELF emission events are analyzed. Correlation between these events and storm indices will also be discussed. References Helliwell, R. A., VLF Emission, in Whistlers and Related Ionospheric Phenomena, Stanford University Press, Stanford, California, 1965. Wang . Y. C., K. Wang, H. T. Su, R. R. Hsu, Low-Latitude ELF-Whistlers observed in Taiwan, Geophys. Res. Lett., 32, L08102, doi:10.1029/2005GL022412, 20

Assessment of Pneumatic Controller Emission Measurements ...

EPA Pesticide Factsheets

Oil and Natural Gas (ONG) production facilities have the potential to emit greenhouse gases such as methane (CH4) and other hydrocarbons (HCs) to the atmosphere. ONG production sites have multiple emission sources including storage tank venting, enclosed combustion devices, engine exhaust, pneumatic controllers and uncontrolled leaks. Accounting for up to 37.8 percent of CH4 emissions, pneumatic controllers are one of the most significant sources of CH4 in ONG production field operations. Recent measurement studies used the only commercially-available high volume sampling (HVS) technology (Bacharach Hi Flow Sampler, Bacharach, Inc., New Kensington, PA) to quantify CH4 emission rates of pneumatic devices on ONG production pads and compare to inventory estimates. Other studies indicate that this HVS may malfunction, causing underestimates of emissions in certain scenarios encountered in ONG production and should not be used for some sources such as heavy emissions from condensate storage tanks. The HVS malfunction can occur on relatively large emissions, where the measured leak concentrations exceed 5%, and is ascribed to a sensor transition failure in the instrument. The HVS malfunction is believed to be exacerbated by several factors (large emission rates, amount of non-CH4 HCs in the emission stream, non-optimal HVS calibration frequency, firmware, and emission measurement coupling geometries). The degree to which HVS measurements of emissions from pneumatic co

Time-resolved characterization of primary particle emissions and secondary particle formation from a modern gasoline passenger car

NASA Astrophysics Data System (ADS)

Karjalainen, Panu; Timonen, Hilkka; Saukko, Erkka; Kuuluvainen, Heino; Saarikoski, Sanna; Aakko-Saksa, Päivi; Murtonen, Timo; Bloss, Matthew; Dal Maso, Miikka; Simonen, Pauli; Ahlberg, Erik; Svenningsson, Birgitta; Brune, William Henry; Hillamo, Risto; Keskinen, Jorma; Rönkkö, Topi

2016-07-01

Changes in vehicle emission reduction technologies significantly affect traffic-related emissions in urban areas. In many densely populated areas the amount of traffic is increasing, keeping the emission level high or even increasing. To understand the health effects of traffic-related emissions, both primary (direct) particulate emission and secondary particle formation (from gaseous precursors in the exhaust emissions) need to be characterized. In this study, we used a comprehensive set of measurements to characterize both primary and secondary particulate emissions of a Euro 5 level gasoline passenger car. Our aerosol particle study covers the whole process chain in emission formation, from the tailpipe to the atmosphere, and also takes into account differences in driving patterns. We observed that, in mass terms, the amount of secondary particles was 13 times higher than the amount of primary particles. The formation, composition, number and mass of secondary particles was significantly affected by driving patterns and engine conditions. The highest gaseous and particulate emissions were observed at the beginning of the test cycle when the performance of the engine and the catalyst was below optimal. The key parameter for secondary particle formation was the amount of gaseous hydrocarbons in primary emissions; however, also the primary particle population had an influence.

Modeling Ozone in the Eastern U.S. using a Fuel-Based Mobile Source Emissions Inventory.

PubMed

McDonald, Brian C; McKeen, Stuart A; Cui, Yu Yan; Ahmadov, Ravan; Kim, Si-Wan; Frost, Gregory J; Pollack, Ilana B; Peischl, Jeff; Ryerson, Thomas B; Holloway, John S; Graus, Martin; Warneke, Carsten; Gilman, Jessica B; de Gouw, Joost A; Kaiser, Jennifer; Keutsch, Frank N; Hanisco, Thomas F; Wolfe, Glenn M; Trainer, Michael

2018-06-22

Recent studies suggest overestimates in current U.S. emission inventories of nitrogen oxides (NO x = NO + NO 2 ). Here, we expand a previously developed fuel-based inventory of motor-vehicle emissions (FIVE) to the continental U.S. for the year 2013, and evaluate our estimates of mobile source emissions with the U.S. Environmental Protection Agency's National Emissions Inventory (NEI) interpolated to 2013. We find that mobile source emissions of NO x and carbon monoxide (CO) in the NEI are higher than FIVE by 28% and 90%, respectively. Using a chemical transport model, we model mobile source emissions from FIVE, and find consistent levels of urban NO x and CO as measured during the Southeast Nexus (SENEX) Study in 2013. Lastly, we assess the sensitivity of ozone (O 3 ) over the Eastern U.S. to uncertainties in mobile source NO x emissions and biogenic volatile organic compound (VOC) emissions. The ground-level O 3 is sensitive to reductions in mobile source NO x emissions, most notably in the Southeastern U.S. and during O 3 exceedance events, under the revised standard proposed in 2015 (>70 ppb, 8 h maximum). This suggests that decreasing mobile source NO x emissions could help in meeting more stringent O 3 standards in the future.

Strategies for enhanced deammonification performance and reduced nitrous oxide emissions.

PubMed

Leix, Carmen; Drewes, Jörg E; Ye, Liu; Koch, Konrad

2017-07-01

Deammonification's performance and associated nitrous oxide emissions (N 2 O) depend on operational conditions. While studies have investigated factors for high performances and low emissions separately, this study investigated optimizing deammonification performance while simultaneously reducing N 2 O emissions. Using a design of experiment (DoE) method, two models were developed for the prediction of the nitrogen removal rate and N 2 O emissions during single-stage deammonification considering three operational factors (i.e., pH value, feeding and aeration strategy). The emission factor varied between 0.7±0.5% and 4.1±1.2% at different DoE-conditions. The nitrogen removal rate was predicted to be maximized at settings of pH 7.46, intermittent feeding and aeration. Conversely, emissions were predicted to be minimized at the design edges at pH 7.80, single feeding, and continuous aeration. Results suggested a weak positive correlation between the nitrogen removal rate and N 2 O emissions, thus, a single optimizing operational set-point for maximized performance and minimized emissions did not exist. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evaluations of in-use emission factors from off-road construction equipment

NASA Astrophysics Data System (ADS)

Cao, Tanfeng; Durbin, Thomas D.; Russell, Robert L.; Cocker, David R.; Scora, George; Maldonado, Hector; Johnson, Kent C.

2016-12-01

Gaseous and particle emissions from construction engines contribute an important fraction of the total air pollutants released into the atmosphere and are gaining increasing regulatory attention. Robust quantification of nitrogen oxides (NOx) and particulate matter (PM) emissions are necessary to inventory the contribution of construction equipment to atmospheric loadings. Theses emission inventories require emissions factors from construction equipment as a function of equipment type and modes of operation. While the development of portable emissions measurement systems (PEMS) has led to increased studies of construction equipment emissions, emissions data are still much more limited than for on-road vehicles. The goal of this research program was to obtain accurate in-use emissions data from a test fleet of newer construction equipment (model year 2002 or later) using a Code of Federal Requirements (CFR) compliant PEMS system. In-use emission measurements were made from twenty-seven pieces of construction equipment, which included four backhoes, six wheel loaders, four excavators, two scrapers (one with two engines), six bulldozers, and four graders. The engines ranged in model year from 2003 to 2012, in rated horsepower (hp) from 92 to 540 hp, and in hours of operation from 24 to 17,149 h. This is the largest study of off-road equipment emissions using 40 CFR part 1065 compliant PEMS equipment for all regulated gaseous and particulate emissions.

Quantifying the emissions of HCN from on-road vehicles in urban areas

NASA Astrophysics Data System (ADS)

Moussa, S. G.; Leithead, A.; Wentzell, J. J.; Lu, G.; Li, S.; Brook, J.; Liggio, J.

2013-12-01

Hydrogen Cyanide (HCN), has been considered a marker for biomass burning emissions. Despite its adverse health impacts, estimate of its global sources and sinks are highly uncertain due to a limited number of field and laboratory studies. In particular, HCN emissions from automobile exhaust are not well constrained for modern vehicles, and thought to be relatively small compared to emissions from biomass burning. In the current study, HCN emissions from individual diesel and gasoline vehicles were quantified as a function of engine driving mode, and fuel type. Proton transfer Reaction-Time of Flight-Mass spectrometry (PTR-ToF-MS) was used to measure HCN emissions from diesel engines operating on ultra-low sulfur diesel (ULSD) and various bio-diesel blends including Soy, Tallow, and Canola. Significant emissions of HCN were observed from all vehicles, and enhanced with the use of biodiesel. In addition, ambient measurements of HCN in a traffic dominated urban area in Toronto, Canada demonstrated that a correlation between HCN, and traditional vehicle emissions markers such as benzene and xylenes exists and indicating that HCN has the potential to be a marker of fuel combustion. The ambient data and the calculated emission factors further suggest that vehicular emissions are a major source of HCN even in the presence of biomass burning, and that near roadway conditions may represent the dominant exposure pathway to HCN in urban areas. Results of this study have important implications on HCN global budget, health impacts in urban areas and the effect of alternate fuels on the emissions of this toxic species.

Interannual variation in nitrous oxide emissions from perennial ryegrass/white clover grassland used for dairy production.

PubMed

Burchill, William; Li, Dejun; Lanigan, Gary J; Williams, Micheal; Humphreys, James

2014-10-01

Nitrous oxide (N2 O) emissions are subject to intra- and interannual variation due to changes in weather and management. This creates significant uncertainties when quantifying estimates of annual N2 O emissions from grazed grasslands. Despite these uncertainties, the majority of studies are short-term in nature (<1 year) and as a consequence, there is a lack of data on interannual variation in N2 O emissions. The objectives of this study were to (i) quantify annual N2 O emissions and (ii) assess the causes of interannual variation in emissions from grazed perennial ryegrass/white clover grassland. Nitrous oxide emissions were measured from fertilized and grazed perennial ryegrass/white clover grassland (WC) and from perennial ryegrass plots that were not grazed and did not receive N input (GB), over 4 years from 2008 to 2012 in Ireland (52°51'N, 08°21'W). The annual N2 O-N emissions (kg ha(-1); mean ± SE) ranged from 4.4 ± 0.2 to 34.4 ± 5.5 from WC and from 1.7 ± 0.8 to 6.3 ± 1.2 from GB. Interannual variation in N2 O emissions was attributed to differences in annual rainfall, monthly (December) soil temperatures and variation in N input. Such substantial interannual variation in N2 O emissions highlights the need for long-term studies of emissions from managed pastoral systems. © 2014 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.

Methane and nitrous oxide emissions from municipal wastewater treatment - results from a long-term study.

PubMed

Daelman, M R J; van Voorthuizen, E M; van Dongen, L G J M; Volcke, E I P; van Loosdrecht, M C M

2013-01-01

Methane and nitrous oxide emissions from a fully covered municipal wastewater treatment plant were measured on-line during 16 months. At the plant under study, nitrous oxide contributed three-quarters to the plant's carbon footprint, while the methane emission was slightly larger than the indirect carbon dioxide emission related to the plant's electricity and natural gas consumption. This contrasted with two other wastewater treatment plants, where more than 80% of the carbon footprint came from the indirect carbon dioxide emission. The nitrous oxide emission exhibited a seasonal dynamic, of which the cause remains unclear. Three types of air filter were investigated with regard to their effectiveness to remove methane from the off-gas.

SPATIAL DISTRIBUTIONS OF ABSORPTION, LOCAL SUPPRESSION, AND EMISSIVITY REDUCTION OF SOLAR ACOUSTIC WAVES IN MAGNETIC REGIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chou, D.-Y.; Yang, M.-H.; Zhao Hui

Observed acoustic power in magnetic regions is lower than the quiet Sun because of absorption, emissivity reduction, and local suppression of solar acoustic waves in magnetic regions. In the previous studies, we have developed a method to measure the coefficients of absorption, emissivity reduction, and local suppression of sunspots. In this study, we go one step further to measure the spatial distributions of three coefficients in two active regions, NOAA 9055 and 9057. The maps of absorption, emissivity reduction, and local suppression coefficients correlate with the magnetic map, including plage regions, except the emissivity reduction coefficient of NOAA 9055 wheremore » the emissivity reduction coefficient is too weak and lost among the noise.« less

Modeling Emissions and Vertical Plume Transport of Crop Residue Burning Experiments in the Pacific Northwest

NASA Astrophysics Data System (ADS)

Zhou, L.; Baker, K. R.; Napelenok, S. L.; Pouliot, G.; Elleman, R. A.; ONeill, S. M.; Urbanski, S. P.; Wong, D. C.

2017-12-01

Crop residue burning has long been a common practice in agriculture with the smoke emissions from the burning linked to negative health impacts. A field study in eastern Washington and northern Idaho in August 2013 consisted of multiple burns of well characterized fuels with nearby surface and aerial measurements including trace species concentrations, plume rise height and boundary layer structure. The chemical transport model CMAQ (Community Multiscale Air Quality Model) was used to assess the fire emissions and subsequent vertical plume transport. The study first compared assumptions made by the 2014 National Emission Inventory approach for crop residue burning with the fuel and emissions information obtained from the field study and then investigated the sensitivity of modeled carbon monoxide (CO) and PM2.5 concentrations to these different emission estimates and plume rise treatment with CMAQ. The study suggests that improvements to the current parameterizations are needed in order for CMAQ to reliably reproduce smoke plumes from burning. In addition, there is enough variability in the smoke emissions, stemming from variable field-specific information such as field size, that attempts to model crop residue burning should use field-specific information whenever possible.

Development of operating mode distributions for different types of roadways under different congestion levels for vehicle emission assessment using MOVES.

PubMed

Qi, Yi; Padiath, Ameena; Zhao, Qun; Yu, Lei

2016-10-01

The Motor Vehicle Emission Simulator (MOVES) quantifies emissions as a function of vehicle modal activities. Hence, the vehicle operating mode distribution is the most vital input for running MOVES at the project level. The preparation of operating mode distributions requires significant efforts with respect to data collection and processing. This study is to develop operating mode distributions for both freeway and arterial facilities under different traffic conditions. For this purpose, in this study, we (1) collected/processed geographic information system (GIS) data, (2) developed a model of CO2 emissions and congestion from observations, (3) implemented the model to evaluate potential emission changes from a hypothetical roadway accident scenario. This study presents a framework by which practitioners can assess emission levels in the development of different strategies for traffic management and congestion mitigation. This paper prepared the primary input, that is, the operating mode ID distribution, required for running MOVES and developed models for estimating emissions for different types of roadways under different congestion levels. The results of this study will provide transportation planners or environmental analysts with the methods for qualitatively assessing the air quality impacts of different transportation operation and demand management strategies.

EMISSIONS FROM THE BURNING OF VEGETATIVE DEBRIS IN AIR CURTAIN DESTRUCTORS

EPA Science Inventory

Although no data has been published on emissions from construction and demolition (C&D) debris burned in an air curtain destructor (ACD), a few studies provide information on emissions from combustion of vegetative debris. These results are compared to studies of open burning of...

Characterization of in-use emissions from TxDOT's non-road equipment fleet : final report.

DOT National Transportation Integrated Search

2010-08-01

The objective of this document is to present the findings of the study characterizing in-use emissions of TxDOT's non-road diesel equipment. This document presents literature reviews of emission reduction technologies and emission control measures pr...

Does trade openness affect CO2 emissions: evidence from ten newly industrialized countries?

PubMed

Zhang, Shun; Liu, Xuyi; Bae, Junghan

2017-07-01

This paper examines whether the hypothetical environmental Kuznet curve (EKC) exists or not and investigates how trade openness affects CO 2 emissions, together with real GDP and total primary energy consumption. The study sample comprises ten newly industrialized countries (NICs-10) from 1971 to 2013. The results support the existence of hypothetical EKC and indicate that trade openness negatively and significantly affects emissions, while real GDP and energy do positive effects of emissions. Moreover, the empirical results of short-run causalities indicate feedback hypothetical linkage of real GDP and trade, unidirectional linkages from energy to emissions, and from trade to energy. The error correction terms (ECTs) reveal in the long run, feedback linkages of emissions, real GDP, and trade openness, while energy Granger causes emissions, real GDP, and trade, respectively. The study recommendations are that our policymakers should encourage and expand the trade openness in these countries, not only to restrain CO 2 emissions but also to boost their growth.

[Evaluation indices of greenhouse gas mitigation technologies in cropland ecosystem].

PubMed

Li, Jian-zheng; Wang, Ying-chun; Wang, Li-gang; Li, Hu; Qiu, Jian-jun; Wang, Dao-long

2015-01-01

In spite of the increasing studies on greenhouse gas (GHG) emissions mitigation technologies, there is still a lack of systematic indices for evaluation of their overall impacts in croplands. In this study, we collected all the indices relating to greenhouse gas emissions and analyzed each index following the principles of representativeness, objectivity, completeness, dominance and operability. Finally, we proposed evaluation indices for mitigation technologies based on the current situation of China. Crop yield per unit area was proposed as a constrained index, and greenhouse gas emissions intensity, defined as GHG emissions per unit of produced yield, was proposed as comprehensive index to evaluate the greenhouse effect of various croplands mitigation technologies. Calculation of GHG emissions intensity involved yield, change of soil organic carbon, direct N2O emissions, paddy CH4 emissions and direct and indirect emissions from inputs into croplands. By following these evaluation indices, the greenhouse effect of the technologies could be well evaluated, which could provide scientific basis for their further adoption.

Estimating shipping emissions in the region of the Sea of Marmara, Turkey.

PubMed

Deniz, Cengiz; Durmuşoğlu, Yalçin

2008-02-01

Ship emissions are significantly increasing globally and have remarkable impact on air quality on sea and land. These emissions contribute serious adverse health and environmental effects. Territorial waters, inland seas and ports are the regions most affected by ship emissions. As an inland sea the Sea of Marmara is an area that has too much ship traffic. Since the region of the Marmara is highly urbanized, emissions from ships affect human health and the overall environment. In this paper exhaust gas emissions from ships in the Sea of Marmara and the Turkish Straits are calculated by utilizing the data acquired in 2003. Main engine types, fuel types, operations types, navigation times and speeds of vessels are taken into consideration in the study. Total emissions from ships in the study area were estimated as 5,451,224 t y(-1) for CO(2), 111,039 t y(-1) for NO(x), 87,168 t y(-1) for SO(2), 20,281 t y(-1) for CO, 5801 t y(-1) for VOC, 4762 t y(-1) for PM. The shipping emissions in the region are equivalent to 11% of NO(x) 0.1% of CO and 0.12% of PM of the corresponding total emissions in Turkey. The shipping emissions in the area are 46% of NO(x), 25% of PM and 1.5% of CO of road traffic emissions in Turkey data between which and correspond to a higher level than aircraft emissions and rail emissions in Turkey.

Mercury mass flow in iron and steel production process and its implications for mercury emission control.

PubMed

Wang, Fengyang; Wang, Shuxiao; Zhang, Lei; Yang, Hai; Gao, Wei; Wu, Qingru; Hao, Jiming

2016-05-01

The iron and steel production process is one of the predominant anthropogenic sources of atmospheric mercury emissions worldwide. In this study, field tests were conducted to study mercury emission characteristics and mass flows at two iron and steel plants in China. It was found that low-sulfur flue gas from sintering machines could contribute up to 41% of the total atmospheric mercury emissions, and desulfurization devices could remarkably help reduce the emissions. Coal gas burning accounted for 17%-49% of the total mercury emissions, and therefore the mercury control of coal gas burning, specifically for the power plant burning coal gas to generate electricity, was significantly important. The emissions from limestone and dolomite production and electric furnaces can contribute 29.3% and 4.2% of the total mercury emissions from iron and steel production. More attention should be paid to mercury emissions from these two processes. Blast furnace dust accounted for 27%-36% of the total mercury output for the whole iron and steel production process. The recycling of blast furnace dust could greatly increase the atmospheric mercury emissions and should not be conducted. The mercury emission factors for the coke oven, sintering machine and blast furnace were 0.039-0.047gHg/ton steel, and for the electric furnace it was 0.021gHg/ton steel. The predominant emission species was oxidized mercury, accounting for 59%-73% of total mercury emissions to air. Copyright © 2016. Published by Elsevier B.V.

A fuel-based approach for emission factor development for highway paving construction equipment in China.

PubMed

Li, Zhen; Zhang, Kaishan; Pang, Kaili; Di, Baofeng

2016-12-01

The objective of this paper is to develop and demonstrate a fuel-based approach for emissions factor estimation for highway paving construction equipment in China for better accuracy. A highway construction site in Chengdu was selected for this study with NO emissions being characterized and demonstrated. Four commonly used paving equipment, i.e., three rollers and one paver were selected in this study. A portable emission measurement system (PEMS) was developed and used for emission measurements of selected equipment during real-world highway construction duties. Three duty modes were defined to characterize the NO emissions, i.e., idling, moving, and working. In order to develop a representative emission factor for these highway construction equipment, composite emission factors were estimated using modal emission rates and the corresponding modal durations in the process of typical construction duties. Depending on duty mode and equipment type, NO emission rate ranged from 2.6-63.7mg/s and 6.0-55.6g/kg-fuel with the fuel consumption ranging from 0.31-4.52 g/s correspondingly. The NO composite emission factor was estimated to be 9-41mg/s with the single-drum roller being the highest and double-drum roller being the lowest and 6-30g/kg-fuel with the pneumatic tire roller being the highest while the double-drum roller being the lowest. For the paver, both time-based and fuel consumption-based NO composite emission rates are higher than all of the rollers with 56mg/s and 30g/kg-fuel, respectively. In terms of time-based quantity, the working mode contributes more than the other modes with idling being the least for both emissions and fuel consumption. In contrast, the fuel-based emission rate appears to have less variability in emissions. Thus, in order to estimate emission factors for emission inventory development, the fuel-based emission factor may be selected for better accuracy. The fuel-based composite emissions factors will be less variable and more accurate than time-based emission factors. As a consequence, emissions inventory developed using this approach will be more accurate and practical.

Quantification of Shipping Emissions in the Eastern Mediterranean and Comparison with Satellite Observations

NASA Astrophysics Data System (ADS)

Kilic, A.; Unal, A.; Kindap, T.; Karaca, M.; Khan, M. N.

2010-12-01

Shipping is considered as one of the main emission sources worldwide. Recent studies suggest that, in the Mediterrenean, ship emissions are responsible for 10-50% of black carbon, 2-12% ozone in the surface layer and 5-20% for nitrogen dioxide atmospheric column burden (Marmer et al., 2009). It is, therefore, essential to have an accurate emissions estimation for ships. Marmara Sea, an inland sea connecting the Mediterrenean to the Black Sea, has significant marine activity. Marmara region, surrounding the Marmara Sea, has over 30 million population (including Istanbul megacity) with significant emission sources (e.g., on-road traffic, industry). Emission amounts from ships can be calculated based on two different methodologies, one is according to the total amount of bunker fuels for maritime transport sold which is called top down approach and the other is shipping activity-based bottom-up approach. The top-down estimation method is not suitable for calculations of shipping emissions in Turkey since fuel sales cannot be accurately obtained. Also, top-down approaches possibly have some errors, since data assumptions for the average engine power, engine operating hours and emission factors are the most important uncertain inputs. Previously, a few studies based on bottom-up aproach have been carried on about shipping emissions in Marmara Sea according to the shipping statistics belong to Istanbul and Canakkale Straits and port regions. These studies were mainly depending on very rough assumptions such as avearage ship speed, fixed ships routes, generalized engine types and average fuel consumptions. Deniz C. (2008) estimated shipping emissions in 2003, for Marmara Sea and Turkish Straits as 111,000 tons for NOx, 87,000 tons for SO2, 5,451,000 tons for CO2, 4762 tons for PM. Although- between 2003 and 2008- there is approximately 15% increase in number of ships passsing through Turkish Straits, this study shows that, shippings emissions for the same region are estimated to be more than 3 times of previous studies. In this study, Automatic Information System (AIS) records of marine vessels (having 1 minute temporal resolution) for over 10,000 ships operating at the study area (including Marmara Sea, Istanbul and Canakkale Straits and some parts of Black Sea and Aegian Sea) were obtained from Turkish Undersecretariat for Maritime Affairs for the period between August 2008 and August 2009. These records include the position of the ships, gross tonnage and ship types. Using energy based emission factors for each operation mode, minute-by-minute emissions were estimated. Annual emission totals for merchant ships were estimated as 605,000 tons for NOX; 495,000 tons for SO2; 25,600 tons for HC; 53,300 tons for PM and 29,630,000 tons for CO2. This paper presents the methodology and the findings of the emissions estimates for ships. The results will also be compared to satellite observations. For this purpose, CO measurements from MOPITT and SO2 measurements from OMI will be utilized.

Coherent manipulation of spontaneous emission spectra in coupled semiconductor quantum well structures.

PubMed

Chen, Aixi

2014-11-03

In triple coupled semiconductor quantum well structures (SQWs) interacting with a coherent driving filed, a coherent coupling field and a weak probe field, spontaneous emission spectra are investigated. Our studies show emission spectra can easily be manipulated through changing the intensity of the driving and coupling field, detuning of the driving field. Some interesting physical phenomena such as spectral-line enhancement/suppression, spectral-line narrowing and spontaneous emission quenching may be obtained in our system. The theoretical studies of spontaneous emission spectra in SQWS have potential application in high-precision spectroscopy. Our studies are based on the real physical system [Appl. Phys. Lett.86(20), 201112 (2005)], and this scheme might be realizable with presently available techniques.

A refined method for the calculation of the Non-Methane Volatile Organic Compound emission estimate from Domestic Solvent Usage in Ireland from 1992 to 2014 - A case study for Ireland

NASA Astrophysics Data System (ADS)

Barry, Stephen; O'Regan, Bernadette

2016-08-01

This study describes a new methodology to calculate Non-Methane Volatile Organic Compounds from Domestic Solvent Use including Fungicides over the period 1992-2014. Improved emissions data compiled at a much more refined level can help policy-makers develop more effective policy's to address environmental issues. However, a number of problems were found when member states attempt to use national statistics for Domestic Solvent Use including Fungicides. For instance, EMEP/EEA (2013) provides no guidance regarding which activity data should be used, resulting in emission estimates being potentially inconsistent and un-comparable. Also, previous methods and emission factors described in the EMEP/EEA (2013) guidebook do not exactly match data collected by state agencies. This makes using national statistics difficult. In addition, EMEP/EEA (2013) use broader categories than necessary (e.g. Cosmetics Aerosol/Non Aerosol) to estimate emissions while activity data is available at a more refined level scale (e.g. Personal Cleaning Products, Hair Products, Cosmetics, Deodorants and Perfumes). This can make identifying the drivers of emissions unclear. This study builds upon Tzanidakis et al. (2012) whereby it provides a method for collecting activity data from state statistics, developed country specific emission factors based on a survey of 177 Irish products and importantly, used a new method to account for the volatility of organic compounds found in commonly available domestic solvent containing products. This is the first study to account for volatility based on the characteristics of organic compounds and therefore is considered a more accurate method of accounting for emissions from this emission source. The results of this study can also be used to provide a simple method for other member parties to account for the volatility of organic compounds using sectorial adjustment factors described here. For comparison purposes, emission estimates were calculated using the Tier 1 approach currently used in the emission inventory, using activity data and emission factors unadjusted for volatility and adjusted for volatility. The unadjusted estimate is useful, because it demonstrates the failure to properly account for volatility can produce significantly over-estimated emissions from the Domestic Solvent Usage sector. Unadjusted emissions were found to be 30% lower than the EMEP/EEA (2013) Tier 1 period in 2014. Emissions were found to reduce a further 20.9% when the volatility of the organic compounds was included. This new method shows that member parties may be significantly overestimating emissions from Domestic Solvent Use including pesticides and further work should include refining organic compound content and the sectorial adjustment factor of products.

Emissions Benefits From Renewable Fuels and Other Alternatives for Heavy-Duty Vehicles

NASA Astrophysics Data System (ADS)

Hajbabaei, Maryam

There is a global effort to expand the use of alternative fuels due to their several benefits such as improving air quality with reducing some criteria emissions, reducing dependency on fossil fuels, and reducing greenhouse gases such as carbon dioxide. This dissertation is focused on investigating the impact of two popular alternative fuels, biodiesel and natural gas (NG), on emissions from heavy-duty engines. Biodiesel is one of the most popular renewable fuels with diesel applications. Although biodiesel blends are reported to reduce particulate matter, carbon monoxide, and total hydrocarbon emissions; there is uncertainty on their impact on nitrogen oxides (NOx) emissions. This dissertation evaluated the effect of biodiesel feedstock, biodiesel blend level, engine technology, and driving conditions on NOx emissions. The results showed that NOx emissions increase with 20% and higher biodiesel blends. Also, in this study some strategies were proposed and some fuel formulations were found for mitigating NOx emissions increases with biodiesel. The impact of 5% biodiesel on criteria emissions specifically NOx was also fully studied in this thesis. As a part of the results of this study, 5% animal-based biodiesel was certified for use in California based on California Air Resources Board emissions equivalent procedure. NG is one of the most prominent alternative fuels with larger reserves compared to crude oil. However, the quality of NG depends on both its source and the degree to which it is processed. The current study explored the impact of various NG fuels, ranging from low methane/high energy gases to high methane/low energy gases, on criteria and toxic emissions from NG engines with different combustion and aftertreatment technologies. The results showed stronger fuel effects for the lean-burn technology bus. Finally, this thesis investigated the impact of changing diesel fuel composition on the criteria emissions from a variety of heavy-duty engine technologies. Emissions from an average diesel fuel used throughout the U.S. were compared with a 10% aromatic, ultra-low sulfur diesel fuel used in California with more stringent air quality regulations. The results showed that the emerging aftertreatment technologies eventually eliminate the benefits of the lower aromatic content/higher cetane number diesel fuels.

Large enhancement of UV luminescence emission of ZnO nanoparticles by coupling excitons with Ag surface plasmons

NASA Astrophysics Data System (ADS)

Kuiri, Probodh K.; Pramanik, Subhamay

2018-04-01

For an emitter based on bandgap emission, defect mediated emission has always been considered as the most important loss. Here, a novel approach which can overcome such emission loss is proposed using films of ZnO nanoparticles (NPs) on Ag NPs embedded in silica. The effects of the size of Ag NPs on the enhancement of ultra-violet (UV) photoluminescence (PL) of ZnO NPs for such a system have been studied. For the ZnO NPs without Ag NPs, two emission bands have been seen: one in the UV region and the other one in the visible region. This UV PL emission intensity has been seen to increase significantly with a drastic reduction of the visible PL emission intensity in the case of the sample containing ZnO NPs on silica embedded Ag NPs. A linear increase in UV emission with increase in the size of Ag NPs has been found. For the largest size of Ag NPs (˜10 nm, considered in the present study), the PL emission enhancement becomes about 4 times higher than that of sample without Ag NPs. The observed enhancement of the UV PL emission was caused by coupling between spontaneous emission in ZnO and surface plasmons of Ag. The larger Ag NPs provided a larger scattering cross section in coupling surface plasmons to light leading to an increase in UV emission. Thus, it is possible to convert the useless defect emission to the useful excitonic emission with a large enhancement factor.

Future-year ozone prediction for the United States using updated models and inputs.

PubMed

Collet, Susan; Kidokoro, Toru; Karamchandani, Prakash; Shah, Tejas; Jung, Jaegun

2017-08-01

The relationship between emission reductions and changes in ozone can be studied using photochemical grid models. These models are updated with new information as it becomes available. The primary objective of this study was to update the previous Collet et al. studies by using the most up-to-date (at the time the study was done) modeling emission tools, inventories, and meteorology available to conduct ozone source attribution and sensitivity studies. Results show future-year, 2030, design values for 8-hr ozone concentrations were lower than base-year values, 2011. The ozone source attribution results for selected cities showed that boundary conditions were the dominant contributors to ozone concentrations at the western U.S. locations, and were important for many of the eastern U.S. Point sources were generally more important in the eastern United States than in the western United States. The contributions of on-road mobile emissions were less than 5 ppb at a majority of the cities selected for analysis. The higher-order decoupled direct method (HDDM) results showed that in most of the locations selected for analysis, NOx emission reductions were more effective than VOC emission reductions in reducing ozone levels. The source attribution results from this study provide useful information on the important source categories and provide some initial guidance on future emission reduction strategies. The relationship between emission reductions and changes in ozone can be studied using photochemical grid models, which are updated with new available information. This study was to update the previous Collet et al. studies by using the most current, at the time the study was done, models and inventory to conduct ozone source attribution and sensitivity studies. The source attribution results from this study provide useful information on the important source categories and provide some initial guidance on future emission reduction strategies.

Cationic Organochalcogen with Monomer/Excimer Emissions for Dual-Color Live Cell Imaging and Cell Damage Diagnosis.

PubMed

Chao, Xi-Juan; Wang, Kang-Nan; Sun, Li-Li; Cao, Qian; Ke, Zhuo-Feng; Cao, Du-Xia; Mao, Zong-Wan

2018-04-25

Studies on the development of fluorescent organic molecules with different emission colors for imaging of organelles and their biomedical application are gaining lots of focus recently. Here, we report two cationic organochalcogens 1 and 2, both of which exhibit very weak green emission (Φ 1 = 0.12%; Φ 2 = 0.09%) in dilute solution as monomers, but remarkably enhanced green emission upon interaction with nucleic acids and large red-shifted emission in aggregate state by the formation of excimers at high concentration. More interestingly, the monomer emission and excimer-like emission can be used for dual color imaging of different organelles. Upon passively diffusing into cells, both probes selectively stain nucleoli with strong green emission upon 488 nm excitation, whereas upon 405 nm excitation, a completely different stain pattern by staining lysosomes (for 1) or mitochondria (for 2) with distinct red emission is observed because of the highly concentrated accumulation in these organelles. Studies on the mechanism of the accumulation in lysosomes (for 1) or mitochondria (for 2) found that the accumulations of the probes are dependent on the membrane permeabilization, which make the probes have great potential in diagnosing cell damage by sensing lysosomal or mitochondrial membrane permeabilization. The study is demonstrative, for the first time, of two cationic molecules for dual-color imaging nucleoli and lysosomes (1)/mitochondria (2) simultaneously in live cell based on monomer and excimer-like emission, respectively, and more importantly, for diagnosing cell damage.

Time-resolved characterization of primary and secondary particle emissions of a modern gasoline passenger car

NASA Astrophysics Data System (ADS)

Karjalainen, P.; Timonen, H.; Saukko, E.; Kuuluvainen, H.; Saarikoski, S.; Aakko-Saksa, P.; Murtonen, T.; Dal Maso, M.; Ahlberg, E.; Svenningsson, B.; Brune, W. H.; Hillamo, R.; Keskinen, J.; Rönkkö, T.

2015-11-01

Changes in traffic systems and vehicle emission reduction technologies significantly affect traffic-related emissions in urban areas. In many densely populated areas the amount of traffic is increasing, keeping the emission level high or even increasing. To understand the health effects of traffic related emissions, both primary and secondary particles that are formed in the atmosphere from gaseous exhaust emissions need to be characterized. In this study we used a comprehensive set of measurements to characterize both primary and secondary particulate emissions of a modern gasoline passenger car. Our aerosol particle study covers the whole process chain in emission formation, from the engine to the atmosphere, and takes into account also differences in driving patterns. We observed that in mass terms, the amount of secondary particles was 13 times higher than the amount of primary particles. The formation, composition, number, and mass of secondary particles was significantly affected by driving patterns and engine conditions. The highest gaseous and particulate emissions were observed at the beginning of the test cycle when the performance of the engine and the catalyst was below optimal. The key parameter for secondary particle formation was the amount of gaseous hydrocarbons in primary emissions; however, also the primary particle population had an influence. Thus, in order to enhance human health and wellbeing in urban areas, our study strongly indicates that in future legislation, special attention should be directed into the reduction of gaseous hydrocarbons.

First measurements of a carbon dioxide plume from an industrial source using a ground based mobile differential absorption lidar.

PubMed

Robinson, R A; Gardiner, T D; Innocenti, F; Finlayson, A; Woods, P T; Few, J F M

2014-08-01

The emission of carbon dioxide (CO2) from industrial sources is one of the main anthropogenic contributors to the greenhouse effect. Direct remote sensing of CO2 emissions using optical methods offers the potential for the identification and quantification of CO2 emissions. We report the development and demonstration of a ground based mobile differential absorption lidar (DIAL) able to measure the mass emission rate of CO2 in the plume from a power station. To our knowledge DIAL has not previously been successfully applied to the measurement of emission plumes of CO2 from industrial sources. A significant challenge in observing industrial CO2 emission plumes is the ability to discriminate and observe localised concentrations of CO2 above the locally observed background level. The objectives of the study were to modify our existing mobile infrared DIAL system to enable CO2 measurements and to demonstrate the system at a power plant to assess the feasibility of the technique for the identification and quantification of CO2 emissions. The results of this preliminary study showed very good agreement with the expected emissions calculated by the site. The detection limit obtained from the measurements, however, requires further improvement to provide quantification of smaller emitters of CO2, for example for the detection of fugitive emissions. This study has shown that in principle, remote optical sensing technology will have the potential to provide useful direct data on CO2 mass emission rates.

China CO2 emission accounts 1997–2015

PubMed Central

Shan, Yuli; Guan, Dabo; Zheng, Heran; Ou, Jiamin; Li, Yuan; Meng, Jing; Mi, Zhifu; Liu, Zhu; Zhang, Qiang

2018-01-01

China is the world’s top energy consumer and CO2 emitter, accounting for 30% of global emissions. Compiling an accurate accounting of China’s CO2 emissions is the first step in implementing reduction policies. However, no annual, officially published emissions data exist for China. The current emissions estimated by academic institutes and scholars exhibit great discrepancies. The gap between the different emissions estimates is approximately equal to the total emissions of the Russian Federation (the 4th highest emitter globally) in 2011. In this study, we constructed the time-series of CO2 emission inventories for China and its 30 provinces. We followed the Intergovernmental Panel on Climate Change (IPCC) emissions accounting method with a territorial administrative scope. The inventories include energy-related emissions (17 fossil fuels in 47 sectors) and process-related emissions (cement production). The first version of our dataset presents emission inventories from 1997 to 2015. We will update the dataset annually. The uniformly formatted emission inventories provide data support for further emission-related research as well as emissions reduction policy-making in China. PMID:29337312

China CO2 emission accounts 1997-2015

NASA Astrophysics Data System (ADS)

Shan, Yuli; Guan, Dabo; Zheng, Heran; Ou, Jiamin; Li, Yuan; Meng, Jing; Mi, Zhifu; Liu, Zhu; Zhang, Qiang

2018-01-01

China is the world's top energy consumer and CO2 emitter, accounting for 30% of global emissions. Compiling an accurate accounting of China's CO2 emissions is the first step in implementing reduction policies. However, no annual, officially published emissions data exist for China. The current emissions estimated by academic institutes and scholars exhibit great discrepancies. The gap between the different emissions estimates is approximately equal to the total emissions of the Russian Federation (the 4th highest emitter globally) in 2011. In this study, we constructed the time-series of CO2 emission inventories for China and its 30 provinces. We followed the Intergovernmental Panel on Climate Change (IPCC) emissions accounting method with a territorial administrative scope. The inventories include energy-related emissions (17 fossil fuels in 47 sectors) and process-related emissions (cement production). The first version of our dataset presents emission inventories from 1997 to 2015. We will update the dataset annually. The uniformly formatted emission inventories provide data support for further emission-related research as well as emissions reduction policy-making in China.

Synthesis and characterization of T[Ni(CN){sub 4}].2pyz with T=Fe, Ni; pyz=pyrazine: Formation of T-pyz-Ni bridges

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lemus-Santana, A.A.; Rodriguez-Hernandez, J.; Institute of Materials Science and Technology, University of Havana

2011-08-15

The formation of T-pyz-Ni bridges (pyz=pyrazine) in the T[Ni(CN){sub 4}].2pyz series is known for T=Mn, Zn, Cd and Co but not with T=Fe, Ni. In this contribution the existence of such bridges also for T=Fe, Ni is discussed. The obtained pillared solids, T[Ni(CN){sub 4}].2pyz, were characterized from XRD, TG, UV-Vis, IR, Raman, Moessbauer and magnetic data. Their crystal structures were refined in the orthorhombic Pmna space group from XRD powder patterns. The structural behavior of these solids on cooling down to 77 K was also studied. In the 180-200 K temperature range the occurrence of a structural transition to amore » monoclinic structure (P2{sub 1}/c space group) was observed. No temperature induced spin transition was observed for Fe[Ni(CN){sub 4}].2pyz. The iron (II) was found to be in high spin electronic state and this configuration is preserved on cooling down to 2 K. The magnetic data indicate the occurrence of a low temperature weak anti-ferromagnetic interaction between T metal centers within the T[Ni(CN){sub 4}] layer. In the paramagnetic region for Ni[Ni(CN){sub 4}].2pyz, a reversible temperature induced spin transition for the inner Ni atom was detected. - Graphical abstract: Rippled sheets structure for the pillared solids T[Ni(CN){sub 4}].2pyz. The pyrazine molecule is found forming T-pyz-Ni bridges between neighboring layers. Highlights: > Pillared 2D solids. > Inorganic-organic solids. > Assembling of molecular blocks. > From 1D and 2D building blocks to 3D solids.« less

Water Injection Feasibility for Boeing 747 Aircraft

NASA Technical Reports Server (NTRS)

Daggett, David L.

2005-01-01

Can water injection be offered at a reasonable cost to large airplane operators to reduce takeoff NO( sub x) emissions? This study suggests it may be possible. This report is a contract deliverable to NASA Glenn Research Center from the prime contractor, The Boeing Commercial Airplane Company of Seattle, WA. This study was supported by a separate contract to the Pratt & Whitney Engine Company of Hartford, CT (contract number NNC04QB58P). Aviation continues to grow and with it, environmental pressures are increasing for airports that service commercial airplanes. The feasibility and performance of an emissions-reducing technology, water injection, was studied for a large commercial airplane (e.g., Boeing 747 with PW4062 engine). The primary use of the water-injection system would be to lower NOx emissions while an important secondary benefit might be to improve engine turbine life. A tradeoff exists between engine fuel efficiency and NOx emissions. As engines improve fuel efficiency, by increasing the overall pressure ratio of the engine s compressor, the resulting increased gas temperature usually results in higher NOx emissions. Low-NO(sub x) combustors have been developed for new airplanes to control the increases in NO(sub x) emissions associated with higher efficiency, higher pressure ratio engines. However, achieving a significant reduction of NO(sub x) emissions at airports has been challenging. Using water injection during takeoff has the potential to cut engine NO(sub x) emissions some 80 percent. This may eliminate operating limitations for airplanes flying into airports with emission constraints. This study suggests an important finding of being able to offer large commercial airplane owners an emission-reduction technology that may also save on operating costs.

A predictive analysis of CO2 emissions, environmental policy stringency, and economic growth in China.

PubMed

Ahmed, Khalid; Ahmed, Sidrah

2018-03-28

This study takes environmental policy stringency and economic activity as the controlling variables and forecasts the CO 2 emissions in China up to 2022. In doing so, an application of corrected grey model with convolution is used over the annual time series data between 1990 and 2012. The simulation results show that (1) between 2012 and 2022, CO 2 emissions in China is expected to increase at an average rate of 17.46% annually, raising the emissions intensity from 7.04 in 2012 to 25.461 metric tons per capita by 2022; (2) stringent environmental policies reduce CO 2 emissions-whereas, GDP tends to increase the emissions intensity in China; (3) stringent environmental policies are found to have a negative impact on GDP in China. Based on the empirical findings, the study also provides some policy suggestions to reduce emissions intensity in China.

NO2 DOAS Measurements of Traffic Emissions by Chasing Cars

NASA Astrophysics Data System (ADS)

Zhu, Ying; Lipkowitsch, Ivo; Chan, Ka Lok; Bräu, Melanie; Wenig, Mark

2016-04-01

On this poster we present NO2 measurements using a Cavity-Enhanced DOAS on a measurement bus which we used to chase other vehicles to measure their NO2 emissions. Emissions of nitrogen oxides from on-road vehicles have received highly attention recently due to the increasing trend of ambient NOx level. It is particularly important to identify and quantify the direct emission and secondary formation of NO2 contributed by traffic emissions, in order to study the impact to the local air quality. We sampled on-road emissions in different environments and different driving conditions (e.g. urban, highway, different speeds). We analyse the data set in terms of spatial and temporal variability to search for temporal and spatial patterns. We present mean values sorted for different vehicle types, distance to the target car and travelling speeds to provide an emission data base from this measurement study.

Impacts of Climate Change on Forest Isoprene Emission: Diversity Matters

NASA Astrophysics Data System (ADS)

Wang, B.; Shugart, H. H., Jr.; Lerdau, M.

2016-12-01

Many abiotic and biotic factors influence volatile organic compound (VOC) production and emission by plants; for example, climate warming is widely projected to enhance VOC emissions by stimulating their biosynthesis. The species-dependent nature of VOC production by plants indicates that changes in species abundances may play an important role in determining VOC production and emission at the ecosystem scale. To date, however, the role of species abundances in affecting VOC emissions has not been well studied. We examine the role of forest systems as sources of VOC's in terms of how species diversity and abundance influence isoprene emission under climate warming by using an individual-based forest VOC emission model—UVAFME-VOC 1.0—that can explicitly simulate forest compositional and structural change and VOC production/emission at the individual and canopy scales. We simulate isoprene emissions under two warming scenarios (warming by 2 and 4 °C) for temperate deciduous forests of the southeastern United States, where the dominant isoprene-emitting species are oaks (Quercus). The simulations show that, contrary to previous expectations, a warming by 2 °C does not affect isoprene emissions, while a further warming by 4 °C causes a large reduction of isoprene emissions. Interestingly, climate warming can directly enhance isoprene emission and simultaneously indirectly reduce it by lowering the abundance of isoprene-emitting species. Under gradual continuous warming, the indirect effect outweighs the direct effect, thus reducing overall forest isoprene emission. This modelling study shows that climate warming does not necessarily stimulate ecosystem VOC emissions and, more generally, that ecosystem diversity and composition can play a significant role in determining vegetation VOC emission capacity. Future earth system models and climate-chemistry models should better represent species diversity in projecting climate-air quality feedbacks and making management policy recommendations.

Temperature effects on particulate matter emissions from light-duty, gasoline-powered motor vehicles

EPA Science Inventory

The Kansas City Light-Duty Vehicle Emissions study measured exhaust emissions of regulated and unregulated pollutants from over 500 vehicles randomly recruited in the Kansas City metropolitan area in 2004 and 2005. Vehicle emissions testing occurred during the summer and winter, ...

Measurement of Emissions from Produced Water Ponds: Upstream Oil and Gas Study #1; Final Report

EPA Science Inventory

Significant uncertainty exists regarding air pollutant emissions from upstream oil and gas production operations. Oil and gas operations present unique and challenging emission testing issues due to the large variety and quantity of potential emissions sources. This report summ...

Odor and odorous chemical emissions from animal buildings: part 4-correlations between sensory and chemical measurements

USDA-ARS?s Scientific Manuscript database

This study supplemented the National Air Emissions Monitoring Study (NAEMS) with one year of comprehensive measurements of odor emission at five swine and four dairy buildings. The measurements included both standard human sensory measurements using dynamic forced-choice olfactometry and chemical an...

Generation and characterization of diesel engine combustion emissions from petroleum diesel and soybean biodiesel fuels and application for inhalation exposure studies

EPA Science Inventory

Biodiesel made from the transesterification of plant- and anmal-derived oils is an important alternative fuel source for diesel engines. Although numerous studies have reported health effects associated with petroleum diesel emissions, information on biodiesel emissions are more ...

REFINING FIRE EMISSIONS FOR AIR QUALITY MODELING WITH REMOTELY-SENSED FIRE COUNTS: A WILDFIRE CASE STUDY

EPA Science Inventory

This paper examines the use of Moderate Resolution Imaging Spectroradiometer (MODIS) observed active fire data (pixel counts) to refine the National Emissions Inventory (NEI) fire emission estimates for major wildfire events. This study was motivated by the extremely limited info...

EVALUATION OF EMISSIONS FROM THE OPEN BURNING OF HOUSEHOLD WASTE IN BARRELS - VOLUME 1. TECHNICAL REPORT

EPA Science Inventory

The report gives results of a detailed emissions characterization study undertaken to examine, characterize, and quantify emissions from the simulated burning of household waste in barrels. The study evaluated two waste streams: that of an avid recycler, who removed most of the r...

EVALUATION OF EMISSIONS FROM THE OPEN BURNING OF HOUSEHOLD WASTES IN BARRELS - VOLUME 2. APPENDICES

EPA Science Inventory

The report gives results of a detailed emissions characterization study undertaken to examine, characterize, and quantify emissions from the simulated burning of household waste in barrels. The study evaluated two waste streams: that of an avid recycler, who removed most of the r...

The metabolism of the human brain studied with positron emission tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Greitz, T.; Ingvar, D.H.; Widen, L.

1985-01-01

This volume presents coverage of the use of positron emission tomography (PET) to study the human brain. The contributors assess new developments in high-resolution positron emission tomography, cyclotrons, radiochemistry, and tracer kinetic models, and explore the use of PET in brain energy metabolism, blood flow, and protein synthesis measurements, receptor analysis, and pH determinations, In addition, they discuss the relevance and applications of positron emission tomography from the perspectives of physiology, neurology, and psychiatry.

Economic-environmental modeling of point source pollution in Jefferson County, Alabama, USA.

PubMed

Kebede, Ellene; Schreiner, Dean F; Huluka, Gobena

2002-05-01

This paper uses an integrated economic-environmental model to assess the point source pollution from major industries in Jefferson County, Northern Alabama. Industrial expansion generates employment, income, and tax revenue for the public sector; however, it is also often associated with the discharge of chemical pollutants. Jefferson County is one of the largest industrial counties in Alabama that experienced smog warnings and ambient ozone concentration, 1996-1999. Past studies of chemical discharge from industries have used models to assess the pollution impact of individual plants. This study, however, uses an extended Input-Output (I-O) economic model with pollution emission coefficients to assess direct and indirect pollutant emission for several major industries in Jefferson County. The major findings of the study are: (a) the principal emission by the selected industries are volatile organic compounds (VOC) and these contribute to the ambient ozone concentration; (b) the direct and indirect emissions are significantly higher than the direct emission by some industries, indicating that an isolated analysis will underestimate the emission by an industry; (c) while low emission coefficient industries may suggest industry choice they may also emit the most hazardous chemicals. This study is limited by the assumptions made, and the data availability, however it provides a useful analytical tool for direct and cumulative emission estimation and generates insights on the complexity in choice of industries.

Remote sensing of methane and nitrous oxide fluxes from waste incineration.

PubMed

Gålfalk, Magnus; Bastviken, David

2018-05-01

Incomplete combustion processes lead to the formation of many gaseous byproducts that can be challenging to monitor in flue gas released via chimneys. This study presents ground-based remote sensing approaches to make greenhouse gas (GHG) flux measurements of methane (CH 4 ) and nitrous oxide (N 2 O) from a waste incineration chimney at distances of 150-200 m. The study found emission of N 2 O (corresponding to 30-40 t yr -1 ), which is a consequence of adding the reduction agent urea to decrease NO X emissions due to NO X regulation; a procedure that instead increases N 2 O emissions (which is approximately 300 times more potent as a GHG than CO 2 on a 100-year time scale). CH 4 emissions of 7-11 t yr -1 was also detected from the studied chimney despite the usage of a high incineration temperature. For this particular plant, local knowledge is high and emission estimates at corresponding levels have been reported previously. However, emissions of CH 4 are often not included in GHG emission inventories for waste incineration. This study highlights the importance of monitoring combustion processes, and shows the possibility of surveying CH 4 and N 2 O emissions from waste incineration at distances of several hundred meters. Copyright © 2018 Elsevier Ltd. All rights reserved.

A Study of the X-Ray Emission from Three Radio Pulsars

NASA Technical Reports Server (NTRS)

Slane, Patrick O. (Principal Investigator)

1996-01-01

The subject grant is for work on a study of x-ray emission from isolated pulsars. The purpose of the study was to: determine whether the pulsars were x-ray sources; and, if so, search for evidence of pulsations at the known radio period; and study the nature of the x-ray emission. Observation of the pulsar PSR 0355+54 were obtained, and the analysis of these data is complete. These results were reported at the 183rd AAS Meeting, and in a paper entitled 'X-Ray Emission from PSR 0355+54' which as published in the The Astrophysical Journal. Also obtained an approx. 3 ks PSPC observations of PSR 1642-03. A summary of the results from these data were reported in a Conference Proceedings for the 'New Horizon of X-ray Astronomy' symposium. In addition, as part of a study with a student from the SAO Summer Intern Program, I incorporated ROSAT archival data in an extended study of pulsar emission. These results were reported at the 185th AAS Meeting, and in a paper entitled 'Soft X-ray Emission from Selected Isolated Pulsars' which was published in The Astrophysical Journal (Letters).

National- to port-level inventories of shipping emissions in China

NASA Astrophysics Data System (ADS)

Fu, Mingliang; Liu, Huan; Jin, Xinxin; He, Kebin

2017-11-01

Shipping in China plays a global role, and has led worldwide maritime transportation for the last decade. However, without taking national or local port boundaries into account, it is impossible to determine the responsibility that each local authority has on emission controls, nor compare them with land-based emissions to determine the priority for controlling these emissions. In this study, we provide national- to port-level inventories for China. The results show that in 2013, the total emissions of CO, non-methane volatile organic compounds (NMVOCs), nitrogen oxides (NO x ), particulate matter (PM), SO2 and CO2 were 0.0741 ± 0.0004 Tg•yr-1, 0.0691 ± 0.0004 Tg•yr-1, 1.91 ± 0.01 Tg•yr-1, 0.164 ± 0.001 Tg•yr-1, 1.30 ± 0.01 Tg•yr-1 and 86.3 ± 0.3 Tg•yr-1 in China, respectively. By providing high-resolution spatial distribution maps of these emissions, we identify three hotspots, centered on the Bohai Rim Area, the Yangtze River Delta and Pearl River Delta. These three hotspots account for 8% of the ocean area evaluated in this study, but contribute around 37% of total shipping emissions. Compared with on-road mobile source emissions, NO x and PM emissions from ships are equivalent to about 34% and 29% of the total mobile vehicle emissions in China. Moreover, this study provides detailed emission inventories for 24 ports in the country, which also greatly contributes to our understanding of global shipping emissions, given that eight of these ports rank within the top twenty of the port league table. Several ports in China suffer emissions 12-147 times higher than those at Los Angeles port. The ports of Ningbo-Zhou Shan, Shanghai, Hong Kong and Dalian dominate the port-level inventories, with individual emissions accounting for 28%-31%, 10%-14%, 10%-12% and 8%-14% of total emissions, respectively.

Simulation of Arctic Black Carbon using Hemispheric CMAQ: Role of Russia's BC Emissions, Transport, and Deposition

NASA Astrophysics Data System (ADS)

Huang, K.; Fu, J. S.

2015-12-01

Black carbon plays a unique role in the Arctic climate system due to its multiple effects. It causes Arctic warming by directly absorbing sunlight from space and by darkening the surface albedo of snow and ice, which indirectly leads to further warming and melting, thus inducing an Arctic amplification effect. BC depositions over the Arctic are more sensitive to regions in close proximity. In this study, we reconstruct BC emissions for Russian Federation, which is the country that occupies the largest area in the Arctic Circle. Local Russia information such as activity data, emission factors and other emission source data are used. In 2010, total anthropogenic BC emission of Russia is estimated to be around 254 Gg. Gas flaring, a commonly ignored black carbon source, contributes a dominant 43.9% of Russia's total anthropogenic BC emissions. Other sectors, i.e., residential, transportation, industry, and power plants, contribute 22.0%, 17.8%, 11.5%, and 4.8%, respectively. BC simulations were conducted using the hemispheric version of CMAQ with polar projection. Emission inputs are from a global emissions database EDGAR (Emissions Database for Global Atmospheric Research)-HTAPv2 (Hemispheric Transport of Air Pollution) and EDGAR-HTAPv2 with its Russian part replaced by the newly developed Russian BC emissions, respectively. The simulations using the new Russian BC emission inventory could improve 46 - 61% of the Absorption Aerosol Optical Depth (AAOD) measured at the AERONET sites in Russia throughout the whole year as compared to that using the default HTAPv2 emissions. At the four air monitoring sites (Zeppelin, Barrow, Alert, and Tiksi) in the Arctic Circle, surface BC simulations are improved the most during the Arctic haze periods (October - March). Emission perturbation studies show that Russia's BC emissions contribute over 50% of the surface BC concentrations over the Arctic during the cold seasons. This study demonstrates the good capability of H-CMAQ in simulating the transport of BC particles to the Arctic and suggests that the impact of Russian emissions on the Arctic haze has likely been underestimated, which is one of the causes that previous modeling works struggled in reproducing the BC levels in the Arctic region.

Relationship Study on Land Use Spatial Distribution Structure and Energy-Related Carbon Emission Intensity in Different Land Use Types of Guangdong, China, 1996–2008

PubMed Central

Huang, Yi; Yang, Lei

2013-01-01

This study attempts to discuss the relationship between land use spatial distribution structure and energy-related carbon emission intensity in Guangdong during 1996–2008. We quantized the spatial distribution structure of five land use types including agricultural land, industrial land, residential and commercial land, traffic land, and other land through applying spatial Lorenz curve and Gini coefficient. Then the corresponding energy-related carbon emissions in each type of land were calculated in the study period. Through building the reasonable regression models, we found that the concentration degree of industrial land is negatively correlated with carbon emission intensity in the long term, whereas the concentration degree is positively correlated with carbon emission intensity in agricultural land, residential and commercial land, traffic land, and other land. The results also indicate that land use spatial distribution structure affects carbon emission intensity more intensively than energy efficiency and production efficiency do. These conclusions provide valuable reference to develop comprehensive policies for energy conservation and carbon emission reduction in a new perspective. PMID:23476128

Relationship study on land use spatial distribution structure and energy-related carbon emission intensity in different land use types of Guangdong, China, 1996-2008.

PubMed

Huang, Yi; Xia, Bin; Yang, Lei

2013-01-01

This study attempts to discuss the relationship between land use spatial distribution structure and energy-related carbon emission intensity in Guangdong during 1996-2008. We quantized the spatial distribution structure of five land use types including agricultural land, industrial land, residential and commercial land, traffic land, and other land through applying spatial Lorenz curve and Gini coefficient. Then the corresponding energy-related carbon emissions in each type of land were calculated in the study period. Through building the reasonable regression models, we found that the concentration degree of industrial land is negatively correlated with carbon emission intensity in the long term, whereas the concentration degree is positively correlated with carbon emission intensity in agricultural land, residential and commercial land, traffic land, and other land. The results also indicate that land use spatial distribution structure affects carbon emission intensity more intensively than energy efficiency and production efficiency do. These conclusions provide valuable reference to develop comprehensive policies for energy conservation and carbon emission reduction in a new perspective.

Effect of Temperature and Process on Quantity and Composition of Laboratory-generated Bitumen Emissions.

PubMed

Bolliet, Christophe; Kriech, Anthony J; Juery, Catherine; Vaissiere, Mathieu; Brinton, Michael A; Osborn, Linda V

2015-01-01

In this study we investigated the impact of temperature on emissions as related to various bitumen applications and processes used in commercial products. Bitumen emissions are very complex and can be influenced in quantity and composition by differences in crude source, refining processes, application temperature, and work practices. This study provided a controlled laboratory environment to study five bitumen test materials from three European refineries; three paving grade, one used for primarily roofing and some paving applications, and one oxidized industrial specialty bitumen. Emissions were generated at temperatures between 140°C and 230°C based on typical application temperatures of each product. Emissions were characterized by aerodynamic particle size, total organic matter (TOM), simulated distillation, 40 individual PACs, and fluorescence (FL-PACs) spectroscopy. Results showed that composition of bitumen emissions is influenced by temperature under studied experimental conditions. A distinction between the oxidized bitumen with flux oil (industrial specialty bitumen) and the remaining bitumens was observed. Under typical temperatures used for paving (150°C-170°C), the TOM and PAC concentrations in the emissions were low. However, bitumen with flux oil produced significantly higher emissions at 230°C, laden with high levels of PACs. Flux oil in this bitumen mixture enhanced release of higher boiling-ranged compounds during application conditions. At 200°C and below, concentrations of 4-6 ring PACs were ≤6.51 μg/m(3) for all test materials, even when flux oil was used. Trends learned about emission temperature-process relationships from this study can be used to guide industry decisions to reduce worker exposure during processing and application of hot bitumen.

Volatile organic compounds (VOCs) source profiles of on-road vehicle emissions in China.

PubMed

Hong-Li, Wang; Sheng-Ao, Jing; Sheng-Rong, Lou; Qing-Yao, Hu; Li, Li; Shi-Kang, Tao; Cheng, Huang; Li-Ping, Qiao; Chang-Hong, Chen

2017-12-31

Volatile Organic Compounds (VOCs) source profiles of on-road vehicles were widely studied as their critical roles in VOCs source apportionment and abatement measures in megacities. Studies of VOCs source profiles from on-road motor vehicles from 2001 to 2016 were summarized in this study, with a focus on the comparisons among different studies and the potential impact of different factors. Generally, non-methane hydrocarbons dominated the source profile of on-road vehicle emissions. Carbonyls, potential important components of vehicle emission, were seldom considered in VOCs emissions of vehicles in the past and should be paid more attention to in further study. VOCs source profiles showed some variations among different studies, and 6 factors were extracted and studied due to their impact to VOCs source profile of on-road vehicles. Vehicle types, being dependent on engine types, and fuel types were two dominant factors impacting VOCs sources profiles of vehicles. In comparison, impacts of ignitions, driving conditions and accumulated mileage were mainly due to their influence on the combustion efficiency. An opening and interactive database of VOCs from vehicle emissions was critically essential in future, and mechanisms of sharing and inputting relative research results should be formed to encourage researchers join the database establishment. Correspondingly, detailed quality assurance and quality control procedures were also very important, which included the information of test vehicles and test methods as detailed as possible. Based on the community above, a better uncertainty analysis could be carried out for the VOCs emissions profiles, which was critically important to understand the VOCs emission characteristics of the vehicle emissions. Copyright © 2017 Elsevier B.V. All rights reserved.

A Comparative Cathodoluminescence Emission Study of Feldspathic Glasses in SNC Meteorites and Quenched Melts of These Glasses

NASA Astrophysics Data System (ADS)

Kubny, A.; Jagoutz, E.

2001-12-01

In this study the cathodoluminescence (electron-excited luminescence) emission spectra were measured in the range 200 to 900 nm of individual feldspathic glass grains in the SNC meteorites Shergotty 101, Shergotty 232, ALHA 84001, EETA 79001-47, EETA 79001-276, and Dar al Gani 476 and those of quenched melts of the feldspathic glass grains. The quenching experiments of the original feldspathic glasses were conducted at 1500° C and atmospheric pressure. The aim of this CL emission study was the characterization of feldspathic glasses of SNC meteorites by comparison of the diagnostic spectral features of the feldspathic glasses of SNC meteorites with those of their quenched melts. In the CL emission spectra of the studied feldspathic glasses generally broad bands in the blue (ca. 460 nm), green (ca. 560 nm), and red (ca. 700 nm) can appear. These emission bands are assigned to structural defects (Al-O--Al centers), and the structural incorporation of Mn2+ and Fe3+ , respectively. The blue emission band at about 460 nm attributed to Al-O--Al centers is observed in the spectra of the original feldspathic glasses whereas it is not present (or only in low relative intensity) in the spectra of the quenched melts. The green emission band at 550 to 575 nm assigned to electronic transitions of Mn2+ in M sites is observed in the spectra of the original feldspathic glasses. It is shifted to longer wavelengths of 590 to 605 nm in the spectra of the quenched melts. The occurrence of the red emission band at about 700 nm attributed to electronic transition of Fe3+ in the spectra of the quenched melts of the feldspathic glasses indicates the presence of structural units which allow the occupancy of Fe3+ on tetrahedral sites. The results obtained by CL emission spectroscopy confirm results of Raman spectroscopic studies that the stuctures of feldspathic glasses of the studied SNC meteorites are modified by melting and quenching at atmospheric pressure. Additionally, comparison with published work on CL emission of shocked oligoclases shows that the feldspathic glasses of the studied SNC meteorites are not diaplectic but melt glasses.

Measurement of CO 2, CO, SO 2, and NO emissions from coal-based thermal power plants in India

NASA Astrophysics Data System (ADS)

Chakraborty, N.; Mukherjee, I.; Santra, A. K.; Chowdhury, S.; Chakraborty, S.; Bhattacharya, S.; Mitra, A. P.; Sharma, C.

Measurements of CO 2 (direct GHG) and CO, SO 2, NO (indirect GHGs) were conducted on-line at some of the coal-based thermal power plants in India. The objective of the study was three-fold: to quantify the measured emissions in terms of emission coefficient per kg of coal and per kWh of electricity, to calculate the total possible emission from Indian thermal power plants, and subsequently to compare them with some previous studies. Instrument IMR 2800P Flue Gas Analyzer was used on-line to measure the emission rates of CO 2, CO, SO 2, and NO at 11 numbers of generating units of different ratings. Certain quality assurance (QA) and quality control (QC) techniques were also adopted to gather the data so as to avoid any ambiguity in subsequent data interpretation. For the betterment of data interpretation, the requisite statistical parameters (standard deviation and arithmetic mean) for the measured emissions have been also calculated. The emission coefficients determined for CO 2, CO, SO 2, and NO have been compared with their corresponding values as obtained in the studies conducted by other groups. The total emissions of CO 2, CO, SO 2, and NO calculated on the basis of the emission coefficients for the year 2003-2004 have been found to be 465.667, 1.583, 4.058, and 1.129 Tg, respectively.

Calculation of odour emissions from aircraft engines at Copenhagen Airport.

PubMed

Winther, Morten; Kousgaard, Uffe; Oxbøl, Arne

2006-07-31

In a new approach the odour emissions from aircraft engines at Copenhagen Airport are calculated using actual fuel flow and emission measurements (one main engine and one APU: Auxiliary Power Unit), odour panel results, engine specific data and aircraft operational data for seven busy days. The calculation principle assumes a linear relation between odour and HC emissions. Using a digitalisation of the aircraft movements in the airport area, the results are depicted on grid maps, clearly reflecting aircraft operational statistics as single flights or total activity during a whole day. The results clearly reflect the short-term temporal fluctuations of the emissions of odour (and exhaust gases). Aircraft operating at low engine thrust (taxiing, queuing and landing) have a total odour emission share of almost 98%, whereas the shares for the take off/climb out phases (2%) and APU usage (0.5%) are only marginal. In most hours of the day, the largest odour emissions occur, when the total amount of fuel burned during idle is high. However, significantly higher HC emissions for one specific engine cause considerable amounts of odour emissions during limited time periods. The experimentally derived odour emission factor of 57 OU/mg HC is within the range of 23 and 110 OU/mg HC used in other airport odour studies. The distribution of odour emission results between aircraft operational phases also correspond very well with the results for these other studies. The present study uses measurement data for a representative engine. However, the uncertainties become large when the experimental data is used to estimate the odour emissions for all aircraft engines. More experimental data is needed to increase inventory accuracy, and in terms of completeness it is recommended to make odour emission estimates also for engine start and the fuelling of aircraft at Copenhagen Airport in the future.

A review on black carbon emissions, worldwide and in China.

PubMed

Ni, Mingjiang; Huang, Jianxin; Lu, Shengyong; Li, Xiaodong; Yan, Jianhua; Cen, Kefa

2014-07-01

Black carbon (BC) produced from open burning (OB) and controlled combustion (CC) is a range of carbonaceous products of incomplete combustion of biomass and fossil fuel, and is deemed as one of the major contributors to impact global environment and human health. BC has a strong relationship with POPs, in waste combustion, BC promotes the formation of POPs, and then the transport of POPs in the environment is highly influenced by BC. However less is known about BC formation, measurement and emissions estimation especially in developing countries such as China. Different forms of BC are produced both in CC and OB. BC emission characteristics and combustion parameters which determine BC emissions from CC and OB are discussed. Recent studies showed a lack of common methodology and the resulting data for describing the mechanisms related to BC formation during combustion processes. Because BC is a continuum carbonaceous combustion product, different sampling and measuring methods are used for measuring their emissions with great quantitative uncertainty. We discuss the commonly used BC sampling and measuring methods along with the causes for uncertainty and measures to minimizing the uncertainty. Then, we discuss the estimations of BC emission factors and emission inventory for CC and OB sources. The total emissions of BC from CC and OB in China are also estimated and compared with previous BC emission inventories in this review and we find the inventories tend to be overestimated. As China becomes the largest contributor to global BC emissions, studies for characterizing BC emissions from OB and CC sources are absent in China. Finally, we comment on the current state of BC emission research and identify major deficiencies that need to overcome. Moreover, the advancement in research tools, measuring technique in particular, as discussed in this review is critical for researchers in developing countries to improve their capability to study BC emissions for addressing the growing climate change and public health concerns. Copyright © 2014 Elsevier Ltd. All rights reserved.

On-road emission factors of PM pollutants for light-duty vehicles (LDVs) based on urban street driving conditions

NASA Astrophysics Data System (ADS)

Kam, Winnie; Liacos, James W.; Schauer, James J.; Delfino, Ralph J.; Sioutas, Constantinos

2012-12-01

An on-road sampling campaign was conducted on two major surface streets (Wilshire and Sunset Boulevards) in Los Angeles, CA, to characterize PM components including metals, trace elements, and organic species for three PM size fractions (PM10-2.5, PM2.5-0.25, and PM0.25). Fuel-based emission factors (mass of pollutant per kg of fuel) were calculated to assess the emissions profile of a light-duty vehicle (LDV) traffic fleet characterized by stop-and-go driving conditions that are reflective of urban street driving. Emission factors for metals and trace elements were highest in PM10-2.5 while emission factors for PAHs and hopanes and steranes were highest in PM0.25. PM2.5 emission factors were also compared to previous freeway, roadway tunnel, and dynamometer studies based on an LDV fleet to determine how various environments and driving conditions may influence concentrations of PM components. The on-road sampling methodology deployed in the current study captured substantially higher levels of metals and trace elements associated with vehicular abrasion (Fe, Ca, Cu, and Ba) and crustal origins (Mg and Al) than previous LDV studies. The semi-volatile nature of PAHs resulted in higher levels of PAHs in the particulate phase for LDV tunnel studies (Phuleria et al., 2006) and lower levels of PAHs in the particulate phase for freeway studies (Ning et al., 2008). With the exception of a few high molecular weight PAHs, the current study's emission factors were in between the LDV tunnel and LDV freeway studies. In contrast, hopane and sterane emission factors were generally comparable between the current study, the LDV tunnel, and LDV freeway, as expected given the greater atmospheric stability of these organic compounds. Overall, the emission factors from the dynamometer studies for metals, trace elements, and organic species are lower than the current study. Lastly, n-alkanes (C19-C40) were quantified and alkane carbon preference indices (CPIs) were determined to be in the range of 1-2, indicating substantial anthropogenic source contribution for surface streets in Los Angeles.

Road vehicle emission factors development: A review

NASA Astrophysics Data System (ADS)

Franco, Vicente; Kousoulidou, Marina; Muntean, Marilena; Ntziachristos, Leonidas; Hausberger, Stefan; Dilara, Panagiota

2013-05-01

Pollutant emissions need to be accurately estimated to ensure that air quality plans are designed and implemented appropriately. Emission factors (EFs) are empirical functional relations between pollutant emissions and the activity that causes them. In this review article, the techniques used to measure road vehicle emissions are examined in relation to the development of EFs found in emission models used to produce emission inventories. The emission measurement techniques covered include those most widely used for road vehicle emissions data collection, namely chassis and engine dynamometer measurements, remote sensing, road tunnel studies and portable emission measurements systems (PEMS). The main advantages and disadvantages of each method with regards to emissions modelling are presented. A review of the ways in which EFs may be derived from test data is also performed, with a clear distinction between data obtained under controlled conditions (engine and chassis dynamometer measurements using standard driving cycles) and measurements under real-world operation.

Pilot study to reduce emissions, improve health, and offset BC emissions through the distribution of improved cook stoves in Nepal

NASA Astrophysics Data System (ADS)

Banmali Pradhan, B.; Panday, A. K.; Surapipith, V.

2013-12-01

In most developing countries, wood and other biomass fuels are still the primary source of energy for the majority of the people, particularly the poor. It is estimated that cook stoves account for approximately 20% of global black carbon emissions. In Nepal 87% of energy is supplied from traditional biomass and 75% of households still depend on biomass as a cooking fuel. The substitution of traditional cook stoves with improved cook stoves provides an important way to reduce black carbon emissions. In 2013 the International Centre for Integrated Mountain Development (ICIMOD) has commenced a pilot study that both examines ways to effectively disseminate improved cookstoves across remote rural mountain regions, and also quantifies the resulting changes in emissions, air quality and health. The selected study area is in Bajrabarahi Village in Makawanpur district, to the southwest of Kathmandu. The study area consists of around 1600 households, which are divided into control groups and groups where the cook stove intervention is taking place. The study complements the ';Clean Cooking energy solution for all by 2017' announced by the Government of Nepal recently, and will provide insights to the government on ways to effectively reduce black carbon emissions from cook stoves. To make the study robust and sustainable, local women's group and a local medical institution are involved in the project right from the conceptualization stage. The study region has been chosen in part because the medical school Patan Academy of Health Sciences (PAHS) has already started a long term health assessment in the region, and has built up considerable local contacts. The local women's group is working on the modality of cook stove distribution through micro credit programmes in the village. We will distribute the best available manufactured, fan-assisted cook stoves that are expected to reduce BC emissions the most. Health assessments, emissions estimates, as well as measurements of indoor and outdoor air quality will be done before and after the stoves are disseminated. Having obtained funds for the purchase of improved cook stoves from Nepal's diesel automobile sector, we compare the emissions of black carbon from the sponsoring diesel vehicles with the reduction in black carbon emissions from the sponsored improved cook stoves, thereby pioneering methods to offset black carbon emissions.

On-road emission characteristics of CNG-fueled bi-fuel taxis

NASA Astrophysics Data System (ADS)

Yao, Zhiliang; Cao, Xinyue; Shen, Xianbao; Zhang, Yingzhi; Wang, Xintong; He, Kebin

2014-09-01

To alleviate air pollution and lessen the petroleum demand from the motor vehicle sector in China, natural gas vehicles (NGVs) have been rapidly developed over the last several years. However, the understanding of the real-world emissions of NGVs is very limited. In this study, the emissions from 20 compressed-natural-gas-fueled bi-fuel taxis were measured using a portable emission measurement system (PEMS) under actual driving conditions in Yichang, China. The emission characteristics of the tested vehicles were analyzed, revealing that the average CO2, CO, HC and NOx emissions from the tested compressed-natural-gas (CNG) taxis under urban driving conditions were 1.6, 4.0, 2.0 and 0.98 times those under highway road conditions, respectively. The CO, HC and NOx emissions from Euro 3 CNG vehicles were approximately 40%, 55% and 44% lower than those from Euro 2 vehicles, respectively. Compared with the values for light-duty gasoline vehicles reported in the literature, the CO2 and CO emissions from the tested CNG taxis were clearly lower; however, significant increases in the HC and NOx emissions were observed. Finally, we normalized the emissions under the actual driving cycles of the entire test route to the New European Driving Cycle (NEDC)-based emissions using a VSP modes method developed by North Carolina State University. The simulated NEDC-based CO emissions from the tested CNG taxis were better than the corresponding emissions standards, whereas the simulated NEDC-based HC and NOx emissions greatly exceeded the standards. Thus, more attention should be paid to the emissions from CNG vehicles. As for the CNG-fueled bi-fuel taxis currently in use, the department of environmental protection should strengthen their inspection and supervision to reduce the emissions from these vehicles. The results of this study will be helpful in understanding and controlling emissions from CNG-fueled bi-fuel vehicles in China.

Characterization of methane emissions from five cold heavy oil production with sands (CHOPS) facilities.

PubMed

Roscioli, Joseph R; Herndon, Scott C; Yacovitch, Tara I; Knighton, W Berk; Zavala-Araiza, Daniel; Johnson, Matthew R; Tyner, David R

2018-03-07

Cold heavy oil production with sands (CHOPS) is a common oil extraction method in the Canadian provinces of Alberta and Saskatchewan that can result in significant methane emissions due to annular venting. Little is known about the magnitude of these emissions, nor their contributions to the regional methane budget. Here the authors present the results of field measurements of methane emissions from CHOPS wells and compare them with self-reported venting rates. The tracer ratio method was used not only to analyze total site emissions but at one site it was also used to locate primary emission sources and quantify their contributions to the facility-wide emission rate, revealing the annular vent to be a dominant source. Emissions measured from five different CHOPS sites in Alberta showed large discrepancies between the measured and reported rates, with emissions being mainly underreported. These methane emission rates are placed in the context of current reporting procedures and the role that gas-oil ratio (GOR) measurements play in vented volume estimates. In addition to methane, emissions of higher hydrocarbons were also measured; a chemical "fingerprint" associated with CHOPS wells in this region reveals very low emission ratios of ethane, propane, and aromatics versus methane. The results of this study may inform future studies of CHOPS sites and aid in developing policy to mitigate regional methane emissions. Methane measurements from cold heavy oil production with sand (CHOPS) sites identify annular venting to be a potentially major source of emissions at these facilities. The measured emission rates are generally larger than reported by operators, with uncertainty in the gas-oil ratio (GOR) possibly playing a large role in this discrepancy. These results have potential policy implications for reducing methane emissions in Alberta in order to achieve the Canadian government's goal of reducing methane emissions by 40-45% below 2012 levels within 8 yr.

On the Impact of Granularity of Space-Based Urban CO2 Emissions in Urban Atmospheric Inversions: A Case Study for Indianapolis, IN

NASA Technical Reports Server (NTRS)

Oda, Tomohiro; Lauvaux, Thomas; Lu, Dengsheng; Rao, Preeti; Miles, Natasha L.; Richardson, Scott J.; Gurney, Kevin R.

2017-01-01

Quantifying greenhouse gas (GHG) emissions from cities is a key challenge towards effective emissions management. An inversion analysis from the INdianapolis FLUX experiment (INFLUX) project, as the first of its kind, has achieved a top-down emission estimate for a single city using CO2 data collected by the dense tower network deployed across the city. However, city-level emission data, used as a priori emissions, are also a key component in the atmospheric inversion framework. Currently, fine-grained emission inventories (EIs) able to resolve GHG city emissions at high spatial resolution, are only available for few major cities across the globe. Following the INFLUX inversion case with a global 1x1 km ODIAC fossil fuel CO2 emission dataset, we further improved the ODIAC emission field and examined its utility as a prior for the city scale inversion. We disaggregated the 1x1 km ODIAC non-point source emissions using geospatial datasets such as the global road network data and satellite-data driven surface imperviousness data to a 3030 m resolution. We assessed the impact of the improved emission field on the inversion result, relative to priors in previous studies (Hestia and ODIAC). The posterior total emission estimate (5.1 MtC/yr) remains statistically similar to the previous estimate with ODIAC (5.3 MtC/yr). However, the distribution of the flux corrections was very close to those of Hestia inversion and the model-observation mismatches were significantly reduced both in forward and inverse runs, even without hourly temporal changes in emissions. EIs reported by cities often do not have estimates of spatial extents. Thus, emission disaggregation is a required step when verifying those reported emissions using atmospheric models. Our approach offers gridded emission estimates for global cities that could serves as a prior for inversion, even without locally reported EIs in a systematic way to support city-level Measuring, Reporting and Verification (MRV) practice implementation.

Effects of improved spatial and temporal modeling of on-road vehicle emissions.

PubMed

Lindhjem, Christian E; Pollack, Alison K; DenBleyker, Allison; Shaw, Stephanie L

2012-04-01

Numerous emission and air quality modeling studies have suggested the need to accurately characterize the spatial and temporal variations in on-road vehicle emissions. The purpose of this study was to quantify the impact that using detailed traffic activity data has on emission estimates used to model air quality impacts. The on-road vehicle emissions are estimated by multiplying the vehicle miles traveled (VMT) by the fleet-average emission factors determined by road link and hour of day. Changes in the fraction of VMT from heavy-duty diesel vehicles (HDDVs) can have a significant impact on estimated fleet-average emissions because the emission factors for HDDV nitrogen oxides (NOx) and particulate matter (PM) are much higher than those for light-duty gas vehicles (LDGVs). Through detailed road link-level on-road vehicle emission modeling, this work investigated two scenarios for better characterizing mobile source emissions: (1) improved spatial and temporal variation of vehicle type fractions, and (2) use of Motor Vehicle Emission Simulator (MOVES2010) instead of MOBILE6 exhaust emission factors. Emissions were estimated for the Detroit and Atlanta metropolitan areas for summer and winter episodes. The VMT mix scenario demonstrated the importance of better characterizing HDDV activity by time of day, day of week, and road type. More HDDV activity occurs on restricted access road types on weekdays and at nonpeak times, compared to light-duty vehicles, resulting in 5-15% higher NOx and PM emission rates during the weekdays and 15-40% lower rates on weekend days. Use of MOVES2010 exhaust emission factors resulted in increases of more than 50% in NOx and PM for both HDDVs and LDGVs, relative to MOBILE6. Because LDGV PM emissions have been shown to increase with lower temperatures, the most dramatic increase from MOBILE6 to MOVES2010 emission rates occurred for PM2.5 from LDGVs that increased 500% during colder wintertime conditions found in Detroit, the northernmost city modeled.

Odor and odorous chemical emissions from animal buildings: Part 6.Odor activity value

USDA-ARS?s Scientific Manuscript database

There is a growing concern with air and odor emissions from agricultural facilities. A supplementary research project was conducted to complement the U.S. National Air Emissions Monitoring Study (NAEMS). The overall goal of the project was to establish odor and chemical emission factors for animal...

Contribution of Lubricating Oil to Particulate Matter Emissions from Light-Duty Gasoline Vehicles in Kansas City

EPA Science Inventory

The contribution of lubricating oil to particulate matter (PM) emissions representative of the in-use 2004 light-duty gasoline vehicles fleet is estimated from the Kansas City Light-Duty Vehicle Emissions Study (KCVES). PM emissions are apportioned to lubricating oil and gasoline...

Contribution of Lubricating Oil to Particulate Matter Emissions from Light-duty Gasoline Vehicles in Kansas City

EPA Science Inventory

The contribution of lubricating oil to particulate matter (PM) emissions representative of the in-use 2004 light-duty gasoline vehicles fleet is estimated from the Kansas City Light-Duty Vehicle Emissions Study (KCVES). PM emissions are apportioned to lubricating oil and gasoline...

Laser-Induced-Emission Spectroscopy In Hg/Ar Discharge

NASA Technical Reports Server (NTRS)

Maleki, Lutfollah; Blasenheim, Barry J.; Janik, Gary R.

1992-01-01

Laser-induced-emission (LIE) spectroscopy used to probe low-pressure mercury/argon discharge to determine influence of mercury atoms in metastable 6(Sup3)P(Sub2) state on emission of light from discharge. LIE used to study all excitation processes affected by metastable population, including possible effects on excitation of atoms, ions, and buffer gas. Technique applied to emissions of other plasmas. Provides data used to make more-accurate models of such emissions, exploited by lighting and laser industries and by laboratories studying discharges. Also useful in making quantitative measurements of relative rates and cross sections of direct and two-step collisional processes involving metastable level.

Development of a Comprehensive Community Nitrogen Oxide Emissions Reduction Toolkit (CCNERT)

NASA Astrophysics Data System (ADS)

Sung, Yong Hoon

The main objective of this study is to research and develop a simplified tool to estimate energy use in a community and its associated effects on air pollution. This tool is intended to predict the impacts of selected energy conservation options and efficiency programs on emission reduction. It is intended to help local government and their residents understand and manage information collection and the procedures to be used. This study presents a broad overview of the community-wide energy use and NOx emissions inventory process. It also presents various simplified procedures to estimate each sector's energy use. In an effort to better understand community-wide energy use and its associated NOx emissions, the City of College Station, Texas, was selected as a case study community for this research. While one community might successfully reduce the production of NOx emissions by adopting electricity efficiency programs in its buildings, another community might be equally successful by changing the mix of fuel sources used to generate electricity, which is consumed by the community. In yet a third community low NOx automobiles may be mandated. Unfortunately, the impact and cost of one strategy over another changes over time as major sources of pollution are reduced. Therefore, this research proposes to help community planners answer these questions and to assist local communities with their NOx emission reduction plans by developing a Comprehensive Community NOx Emissions Reduction Toolkit (CCNERT). The proposed simplified tool could have a substantial impact on reducing NOx emission by providing decision-makers with a preliminary understanding about the impacts of various energy efficiency programs on emissions reductions. To help decision makers, this study has addressed these issues by providing a general framework for examining how a community's non-renewable energy use leads to NOx emissions, by quantifying each end-user's energy usage and its associated NOx emissions, and by evaluating the environmental benefits of various types of energy saving options.

High-resolution simulation of link-level vehicle emissions and concentrations for air pollutants in a traffic-populated eastern Asian city

NASA Astrophysics Data System (ADS)

Zhang, Shaojun; Wu, Ye; Huang, Ruikun; Wang, Jiandong; Yan, Han; Zheng, Yali; Hao, Jiming

2016-08-01

Vehicle emissions containing air pollutants created substantial environmental impacts on air quality for many traffic-populated cities in eastern Asia. A high-resolution emission inventory is a useful tool compared with traditional tools (e.g. registration data-based approach) to accurately evaluate real-world traffic dynamics and their environmental burden. In this study, Macau, one of the most populated cities in the world, is selected to demonstrate a high-resolution simulation of vehicular emissions and their contribution to air pollutant concentrations by coupling multimodels. First, traffic volumes by vehicle category on 47 typical roads were investigated during weekdays in 2010 and further applied in a networking demand simulation with the TransCAD model to establish hourly profiles of link-level vehicle counts. Local vehicle driving speed and vehicle age distribution data were also collected in Macau. Second, based on a localized vehicle emission model (e.g. the emission factor model for the Beijing vehicle fleet - Macau, EMBEV-Macau), this study established a link-based vehicle emission inventory in Macau with high resolution meshed in a temporal and spatial framework. Furthermore, we employed the AERMOD (AMS/EPA Regulatory Model) model to map concentrations of CO and primary PM2.5 contributed by local vehicle emissions during weekdays in November 2010. This study has discerned the strong impact of traffic flow dynamics on the temporal and spatial patterns of vehicle emissions, such as a geographic discrepancy of spatial allocation up to 26 % between THC and PM2.5 emissions owing to spatially heterogeneous vehicle-use intensity between motorcycles and diesel fleets. We also identified that the estimated CO2 emissions from gasoline vehicles agreed well with the statistical fuel consumption in Macau. Therefore, this paper provides a case study and a solid framework for developing high-resolution environment assessment tools for other vehicle-populated cities in eastern Asia.

Attribution of CO2 emissions from Brazilian deforestation to domestic and international drivers

NASA Astrophysics Data System (ADS)

Karstensen, J.; Peters, G.

2011-12-01

Efforts to address extensive deforestation to reduce climate change and save primary forests are taking place on a global scale. Whilst several studies have estimated the emissions occurring from deforestation in large rainforests, few studies have investigated the domestic and international drivers sustaining and increasing the deforestation rates. Brazil, having the largest rainforest in the world and one of the highest deforestation rates, is also currently one of the world's largest exporters of soybeans and beef. In this case study we establish the link between Brazilian deforestation and cattle and soybean production, and further attribute emissions to countries and economic sectors through export and import of Brazilian commodities. The emissions from deforestation can therefore be allocated to the countries and sectors consuming goods and services produced on deforested land in Brazil. A land-use change model and deforestation data is coupled with a carbon cycle model to create yearly emission estimates and different emission allocation schemes, depending on emission amortizations and discounting functions for past deforestation. We use an economic multi-regional input-output model (with 112 regions and 57 sectors) to distribute these emissions along agricultural trade routes, through domestic and international consumption in 2004. With our implementation we find that around 80 % of emissions from deforested land is due to cattle grazing, while agricultural transition effects suggests soy beans are responsible for about 20 % of the emissions occurring in 2004. Nearly tree quarters of the soy beans are consumed outside Brazil, of which China, Germany and France are the biggest consumers. Soy beans are consumed by a variety of sectors in the food industry. Brazil exports about 30 % of the cattle it produces, where Russia, USA and Germany are among the largest consumers. Cattle consumption mainly occurs in the meat sectors. In this study we estimate the CO2 emissions allocated to the consuming countries and economic sectors, to ultimately distribute responsibility and find the main drivers of Brazilian deforestation.

Source-specific speciation profiles of PM2.5 for heavy metals and their anthropogenic emissions in China.

PubMed

Liu, Yayong; Xing, Jia; Wang, Shuxiao; Fu, Xiao; Zheng, Haotian

2018-08-01

Heavy metals are concerned for its adverse effect on human health and long term burden on biogeochemical cycling in the ecosystem. In this study, a provincial-level emission inventory of 13 kinds of heavy metals including V, Cr, Mn, Co, Ni, Cu, Zn, As, Cd, Sn, Sb, Ba and Pb from 10 anthropogenic sources was developed for China, based on the 2015 national emission inventory of primary particulate matters and source category-specific speciation profiles collected from 50 previous studies measured in China. Uncertainties associated with the speciation profiles were also evaluated. Our results suggested that total emissions of the 13 types of heavy metals in China are estimated at about 58000 ton for the year 2015. The iron production is the dominant source of heavy metal, contributing 42% of total emissions of heavy metals. The emissions of heavy metals vary significantly at regional scale, with largest amount of emissions concentrated in northern and eastern China. Particular, high emissions of Cr, Co, Ni, As and Sb (contributing 8%-18% of the national emissions) are found in Shandong where has large capacity of industrial production. Uncertainty analysis suggested that the implementation of province-specific source profiles in this study significantly reduced the emission uncertainties from (-89%, 289%) to (-99%, 91%), particularly for coal combustion. However, source profiles for industry sectors such as non-metallic mineral manufacturing are quite limited, resulting in a relative high uncertainty. The high-resolution emission inventories of heavy metals are essential not only for their distribution, deposition and transport studies, but for the design of policies to redress critical atmospheric environmental hazards at local and regional scales. Detailed investigation on source-specific profile in China are still needed to achieve more accurate estimations of heavy metals in the future. Copyright © 2018 Elsevier Ltd. All rights reserved.

Mobile Gas and Particulate Emission Studies of the New York City Transit Bus Fleet

NASA Astrophysics Data System (ADS)

Jayne, J. T.; Canagaratna, M.; Herndon, S.; Shorter, J.; Zahniser, M.; Shi, Q.; Kolb, C.; Worsnop, D.; Jimenez, J.; Drewnick, F.; Demerjian, K.; Lanni, T.

2001-12-01

Emissions from both diesel and gasoline powered motor vehicles are a significant source of particulate (PM2.5) and trace gas pollution, especially in urban environments. Emission characterizations of motor vehicles can be performed using a dynamometer but these studies make fleet characterization impractical. Few studies have been performed which characterize emissions from in-use vehicles using a mobile sampling platform. This work describes application of new technology instrumentation for rapid (1-5 second) and real-time characterization of both gas and particulate emissions from in-use vehicles and is part of the PM2.5 Technology Assessment and Characterization Study in New York (PMTACS-NY). An aerosol mass spectrometer (AMS) and a tunable infrared laser differential absorption spectrometer (TILDAS) system were deployed on the Aerodyne Research mobile laboratory designed to "chase" target vehicles in and around the New York City area and measure their emissions under actual driving conditions. The AMS provides particle size and composition information for volatile and semi-volatile matter while the TILDAS system was configured to measure NO, NO2, CO, CH4, SO2 and formaldehyde. In addition to a GPS, an ELPI and a condensation particle counter, the mobile laboratory was also equipped with a CO2 monitor to allow emission ratios to be computed for the targeted vehicles. Emission ratios for both particulate and trace gases are reported for a representative fraction of the NYC Metropolitan Transit Authority (MTA) bus fleet in an effort to characterize new emission control technologies currently implemented by the NYC MTA.

Anthropogenic dust emissions due to livestock trampling in a Mongolian temperate grassland

NASA Astrophysics Data System (ADS)

Munkhtsetseg, Erdenebayar; Shinoda, Masato; Ishizuka, Masahide; Mikami, Masao; Kimura, Reiji; Nikolich, George

2017-09-01

Mongolian grasslands are a natural dust source region and they contribute to anthropogenic dust due to the long tradition of raising livestock there. Past decades of abrupt changes in a nomadic society necessitate a study on the effects of livestock trampling on dust emissions, so that research studies may help maintain a sustainable ecosystem and well-conditioned atmospheric environment. In this study, we conducted a mini wind tunnel experiment (using a PI-SWERL® device) to measure dust emissions fluxes from trampling (at three disturbance levels of livestock density, N) and zero trampling (natural as the background level) at test areas in a Mongolian temperate grassland. Moreover, we scaled anthropogenic dust emissions to natural dust emissions as a relative consequence of livestock trampling. We found a substantial increase in dust emissions due to livestock trampling. This effect of trampling on dust emissions was persistent throughout all wind friction velocities, u* (varying from 0.44 to 0.82 m s-1). Significantly higher dust loading occurs after a certain disturbance level has been reached by the livestock trampling. Our results suggest that both friction velocity (u*) and disturbance level of livestock density (N) have an enormous combinational effect on dust emissions from the trampling test surface. This means that the effect of livestock trampling on dust emissions can be seen or revealed when wind is strong. Our results also emphasize that better management for livestock allocation coupled with strategies to prevent anthropogenic dust loads are needed. However, there are many uncertainties and assumptions to be improved on in this study.

The impact of uncertainty on optimal emission policies

NASA Astrophysics Data System (ADS)

Botta, Nicola; Jansson, Patrik; Ionescu, Cezar

2018-05-01

We apply a computational framework for specifying and solving sequential decision problems to study the impact of three kinds of uncertainties on optimal emission policies in a stylized sequential emission problem.We find that uncertainties about the implementability of decisions on emission reductions (or increases) have a greater impact on optimal policies than uncertainties about the availability of effective emission reduction technologies and uncertainties about the implications of trespassing critical cumulated emission thresholds. The results show that uncertainties about the implementability of decisions on emission reductions (or increases) call for more precautionary policies. In other words, delaying emission reductions to the point in time when effective technologies will become available is suboptimal when these uncertainties are accounted for rigorously. By contrast, uncertainties about the implications of exceeding critical cumulated emission thresholds tend to make early emission reductions less rewarding.

Effects of After-Treatment Control Technologies on Heavy-Duty Diesel Truck Emissions

NASA Astrophysics Data System (ADS)

Preble, C.; Dallmann, T. R.; Kreisberg, N. M.; Hering, S. V.; Harley, R.; Kirchstetter, T.

2015-12-01

Diesel engines are major emitters of nitrogen oxides (NOx) and the black carbon (BC) fraction of particulate matter (PM). Diesel particle filter (DPF) and selective catalytic reduction (SCR) emission control systems that target exhaust PM and NOx have recently become standard on new heavy-duty diesel trucks (HDDT). There is concern that DPFs may increase ultrafine particle (UFP) and total particle number (PN) emissions while reducing PM mass emissions. Also, the deliberate catalytic oxidation of engine-out NO to NO2 in continuously regenerating DPFs may lead to increased tailpipe emission of NO2 and near-roadway concentrations that exceed the 1-hr national ambient air quality standard. Increased NO2 emissions can also promote formation of ozone and secondary PM. We report results from ongoing on-road studies of HDDT emissions at the Port of Oakland and the Caldecott Tunnel in California's San Francisco Bay Area. Emission factors (g pollutant per kg diesel) were linked via recorded license plates to each truck's engine model year and installed emission controls. At both sites, DPF use significantly increased the NO2/NOx emission ratio. DPFs also significantly increased NO2 emissions when installed as retrofits on older trucks with higher baseline NOx emissions. While SCR systems on new trucks effectively reduce total NOx emissions and mitigate these undesirable DPF-related NO2 emissions, they also lead to significant emission of N2O, a potent greenhouse gas. When expressed on a CO2-equivalent basis, the N2O emissions increase offsets the fuel economy gain (i.e., the CO2 emission reduction) associated with SCR use. At the Port, average NOx, BC and PN emission factors from new trucks equipped with DPF and SCR were 69 ± 15%, 92 ± 32% and 66 ± 35% lower, respectively, than modern trucks without these emission controls. In contrast, at the Tunnel, PN emissions from older trucks retrofit with DPFs were ~2 times greater than modern trucks without DPFs. The difference could be related to engine temperature, with highway operation producing greater exhaust temperatures that promote UFP nucleation. These studies indicate that DPF and SCR use can mitigate air quality and climate impacts of diesel truck emissions through reductions in BC and NOx. However, increased emissions of N2O, NO2 and PN may offset some of the benefits.

Using air quality modeling to study source-receptor relationships between nitrogen oxides emissions and ozone exposures over the United States.

PubMed

Tong, Daniel Q; Muller, Nicholas Z; Kan, Haidong; Mendelsohn, Robert O

2009-11-01

Human exposure to ambient ozone (O(3)) has been linked to a variety of adverse health effects. The ozone level at a location is contributed by local production, regional transport, and background ozone. This study combines detailed emission inventory, air quality modeling, and census data to investigate the source-receptor relationships between nitrogen oxides (NO(x)) emissions and population exposure to ambient O(3) in 48 states over the continental United States. By removing NO(x) emissions from each state one at a time, we calculate the change in O(3) exposures by examining the difference between the base and the sensitivity simulations. Based on the 49 simulations, we construct state-level and census region-level source-receptor matrices describing the relationships among these states/regions. We find that, for 43 receptor states, cumulative NO(x) emissions from upwind states contribute more to O(3) exposures than the state's own emissions. In-state emissions are responsible for less than 15% of O(3) exposures in 90% of U.S. states. A state's NO(x) emissions can influence 2 to 40 downwind states by at least a 0.1 ppbv change in population-averaged O(3) exposure. The results suggest that the U.S. generally needs a regional strategy to effectively reduce O(3) exposures. But the current regional emission control program in the U.S. is a cap-and-trade program that assumes the marginal damage of every ton of NO(x) is equal. In this study, the average O(3) exposures caused by one ton of NO(x) emissions ranges from -2.0 to 2.3 ppm-people-hours depending on the state. The actual damage caused by one ton of NO(x) emissions varies considerably over space.

Spatiotemporal Changes of Built-Up Land Expansion and Carbon Emissions Caused by the Chinese Construction Industry.

PubMed

Chuai, Xiaowei; Huang, Xianjin; Lu, Qinli; Zhang, Mei; Zhao, Rongqin; Lu, Junyu

2015-11-03

China is undergoing rapid urbanization, enlarging the construction industry, greatly expanding built-up land, and generating substantial carbon emissions. We calculated both the direct and indirect carbon emissions from energy consumption (anthropogenic emissions) in the construction sector and analyzed built-up land expansion and carbon storage losses from the terrestrial ecosystem. According to our study, the total anthropogenic carbon emissions from the construction sector increased from 3,905×10(4) to 103,721.17×10(4) t from 1995 to 2010, representing 27.87%-34.31% of the total carbon emissions from energy consumption in China. Indirect carbon emissions from other industrial sectors induced by the construction sector represented approximately 97% of the total anthropogenic carbon emissions of the sector. These emissions were mainly concentrated in seven upstream industry sectors. Based on our assumptions, built-up land expansion caused 3704.84×10(4) t of carbon storage loss from vegetation between 1995 and 2010. Cropland was the main built-up land expansion type across all regions. The study shows great regional differences. Coastal regions showed dramatic built-up land expansion, greater carbon storage losses from vegetation, and greater anthropogenic carbon emissions. These regional differences were the most obvious in East China followed by Midsouth China. These regions are under pressure for strong carbon emissions reduction.

An intercomparison of biogenic emissions estimates from BEIS2 and BIOME: Reconciling the differences

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilkinson, J.G.; Emigh, R.A.; Pierce, T.E.

1996-12-31

Biogenic emissions play a critical role in urban and regional air quality. For instance, biogenic emissions contribute upwards of 76% of the daily hydrocarbon emissions in the Atlanta, Georgia airshed. The Biogenic Emissions Inventory System-Version 2.0 (BEIS2) and the Biogenic Model for Emissions (BIOME) are two models that compute biogenic emissions estimates. BEIS2 is a FORTRAN-based system, and BIOME is an ARC/INFO{reg_sign} - and SAS{reg_sign}-based system. Although the technical formulations of the models are similar, the models produce different biogenic emissions estimates for what appear to be essentially the same inputs. The goals of our study are the following: (1)more » Determine why BIOME and BEIS2 produce different emissions estimates; (2) Attempt to understand the impacts that the differences have on the emissions estimates; (3) Reconcile the differences where possible; and (4) Present a framework for the use of BEIS2 and BIOME. In this study, we used the Coastal Oxidant Assessment for Southeast Texas (COAST) biogenics data which were supplied to us courtesy of the Texas Natural Resource Conservation Commission (TNRCC), and we extracted the BEIS2 data for the same domain. We compared the emissions estimates of the two models using their respective data sets BIOME Using TNRCC data and BEIS2 using BEIS2 data.« less

Greenhouse gas emission from the total process of swine manure composting and land application of compost

NASA Astrophysics Data System (ADS)

Zhong, Jia; Wei, Yuansong; Wan, Hefeng; Wu, Yulong; Zheng, Jiaxi; Han, Shenghui; Zheng, Bofu

2013-12-01

Greenhouse gas (GHG) emissions from animal manure management are of great concern in China. However, there are still great uncertainties about China's GHG inventory due to the GHG emission factors partly used default values from the Intergovernmental Panel of Climate Change (IPCC) guidelines. The purpose of this study was to use a case study in Beijing to determine the regional GHG emission factors based on the combination of swine manure composting and land application of the compost with both on-site examination and a life cycle assessment (LCA). The results showed that the total GHG emission factor was 240 kgCO2eq tDS-1 (dry solids), including the direct GHG emission factor of 115 kgCO2eq tDS-1 for swine manure composting and 48 kgCO2eq tDS-1 for land application of the compost. Among the total GHG emissions of 5.06 kgCH4 tDS-1 and 0.13 kgN2O tDS-1, the swine manure composting contributed approximately 89% to CH4 emissions while land application accounted for 92% of N2O emission. Meanwhile, the GHG emission profile from the full process in Beijing in 2015 and 2020 was predicted by the scenario analysis. The composting and land application is a cost-effective way for animal manure management in China considering GHG emissions.

Thermal-infrared spectral observations of geologic materials in emission

NASA Technical Reports Server (NTRS)

Christensen, Philip R.; Luth, Sharon J.

1987-01-01

The thermal-infrared spectra of geologic materials in emission were studied using the prototype Thermal Emission Spectrometer (TES). A variety of of processes and surface modifications that may influence or alter the spectra of primary rock materials were studied. It was confirmed that thermal emission spectra contain the same absorption features as those observed in transmission and reflection spectra. It was confirmed that the TES instrument can be used to obtain relevant spectra for analysis of rock and mineral composition.

Effects of 17β-estradiol on emissions of greenhouse gases in simulative natural water body.

PubMed

Ruan, Aidong; Zhao, Ying; Liu, Chenxiao; Zong, Fengjiao; Yu, Zhongbo

2015-05-01

Environmental estrogens are widely spread across the world and are increasingly thought of as serious contaminators. The present study looks at the influence of different concentrations of 17β-estradiol on greenhouse gas emissions (CO2 , CH4 , and N2 O) in simulated systems to explore the relationship between environmental estrogen-pollution and greenhouse gas emissions in natural water bodies. The present study finds that 17β-estradiol pollution in simulated systems has significant promoting effects on the emissions of CH4 and CO2 , although no significant effects on N2 O emissions. The present study indicates that 17β-estradiol has different effects on the different elements cycles; the mechanism of microbial ecology is under review. © 2015 SETAC.

Model for bremsstrahlung emission accompanying interactions between protons and nuclei from low energies up to intermediate energies: Role of magnetic emission

NASA Astrophysics Data System (ADS)

Maydanyuk, Sergei P.

2012-07-01

A model of the bremsstrahlung emission which accompanies proton decay and collisions of protons off nuclei in the low- to intermediate-energy region has been developed. This model includes spin formalism, a potential approach for describing the interaction between protons and nuclei, and an emission that includes a component of the magnetic emission (defined on the basis of the Pauli equation). For the problem of bremsstrahlung during proton decay the role of magnetic emission is studied by using such a model. For the 146Tm nucleus the following has been studied: (1) How much does the magnetic emission change the full bremsstrahlung spectrum? (2) At which angle is the magnetic emission the most intensive relative to the electric emission? (3) Is there some spatial region where the magnetic emission increases strongly relative to the electric emission? (4) How intensive is the magnetic emission in the tunneling region? (5) Which is the maximal probability? Which value does it equal to at the zero-energy limit of the emitted photons? It is demonstrated that the model is able to describe well enough experimental data of bremsstrahlung emission which accompanies collisions of protons off 9C, 64Cu, and 107Ag nuclei at an incident energy of Tlab=72 MeV (at a photon energy up to 60 MeV) and off 9Be, 12C, and 208Pb nuclei at an incident energy of Tlab=140 MeV (at a photon energy up to 120 MeV).

Criteria and air-toxic emissions from in-use automobiles in the National Low-Emission Vehicle program.

PubMed

Baldauf, Rich W; Gabele, Pete; Crews, William; Snow, Richard; Cook, J Rich

2005-09-01

The U.S. Environmental Protection Agency (EPA) implemented a program to identify tailpipe emissions of criteria and air-toxic contaminants from in-use, light-duty low-emission vehicles (LEVs). EPA recruited 25 LEVs in 2002 and measured emissions on a chassis dynamometer using the cold-start urban dynamometer driving schedule of the Federal Test Procedure. The emissions measured included regulated pollutants, particulate matter, speciated hydrocarbon compounds, and carbonyl compounds. The results provided a comparison of emissions from real-world LEVs with emission standards for criteria and air-toxic compounds. Emission measurements indicated that a portion of the in-use fleet tested exceeded standards for the criteria gases. Real-time regulated and speciated hydrocarbon measurements demonstrated that the majority of emissions occurred during the initial phases of the cold-start portion of the urban dynamometer driving schedule. Overall, the study provided updated emission factor data for real-world, in-use operation of LEVs for improved emissions modeling and mobile source inventory development.

Development of a life-cycle fugitive methane emissions model utilizing device level emissions and activity factors

NASA Astrophysics Data System (ADS)

Englander, J.; Brandt, A. R.

2017-12-01

There has been numerous studies in quantifying the scale of fugitive emissions from across the natural gas value chain. These studies have typically focused on either specific types of equipment (such as valves) or on a single part of the life-cycle of natural gas production (such as gathering stations).1,2 However it has been demonstrated that average emissions factors are not sufficient for representing leaks in the natural gas system.3 In this work, we develop a robust estimate of fugitive emissions rates by incorporating all publicly available studies done at the component up to the process level. From these known studies, we create a database of leaks with normalized nomenclature from which leak estimates can be drawn from actual leak observations. From this database, and parameterized by meta-data such as location, scale of study, or placement in the life-cycle, we construct stochastic emissions factors specific for each process unit. This will be an integrated tool as part of the Oil production greenhouse gas estimator (OPGEE) as well as the Fugitive Emissions Abatement Simulation Toolkit (FEAST) models to enhances their treatment of venting and fugitive emissions, and will be flexible to include user provided data and input parameters.4,51. Thoma, ED et al. Assessment of Uinta Basin Oil and Natural Gas Well Pad Pneumatic Controller Emissions. J. Environ. Prot. 2017. 2. Marchese, AJ et al. Methane Emissions from United States Natural Gas Gathering and Processing. ES&T 2015. doi:10.1021/acs.est.5b02275 3. Brandt, AR et al. Methane Leaks from Natural Gas Systems Follow Extreme Distributions. ES&T 2016. doi:10.1021/acs.est.6b04303 4. El-Houjeiri, HM et al. An open-source LCA tool estimating greenhouse gas emissions from crude oil production using field characteristics. ES&T 2013. doi: 10.1021/es304570m 5. Kemp, CE et al. Comparing Natural Gas Leakage Detection Technologies Using an Open-Source `Virtual Gas Field' Simulator. ES&T 2016. doi:10.1021/acs.est.5b06068

First results from a large, multi-platform study of trace gas and particle emissions from biomass burning

Treesearch

I. R. Burling; R. J. Yokelson; S. K. Akagi; T. J. Johnson; D. W. Griffith; Shawn Urbanski; J. W. Taylor; J. S. Craven; G. R. McMeeking; J. M. Roberts; C. Warneke; P. R. Veres; J. A. de Gouw; J. B. Gilman; W. C. Kuster; WeiMin Hao; D. Weise; H. Coe; J. Seinfeld

2010-01-01

We report preliminary results from a large, multi-component study focused on North American biomass burning that measured both initial emissions and post-emission processing. Vegetation types burned were from the relatively less-studied temperate region of the US and included chaparral, oak savanna, and mixed conifer forest from the southwestern US, and pine understory...

An improved inventory of polychlorinated biphenyls in China: A case study on PCB-153

NASA Astrophysics Data System (ADS)

Xu, Yue; Tian, Chongguo; Wang, Xiaoping; Ma, Jianmin; Tang, Jianhui; Chen, Yingjun; Li, Jun; Zhang, Gan

2018-06-01

Emission inventory of pollutants is essential for the environmental fate study and management of the pollutant. To construct a reasonable PCB (polychlorinated biphenyls) inventory in China, this study estimates PCB usage and emission using power generating capacity, installed capacity of power plants and transformer substations, population density and GDP as surrogates. Inventory of representative PCB (PCB-153) with a resolution of 1/4° latitude × 1/4° longitude in China from 1952 to 2005 was generated and assessed as an example. Totally, about 20.3 kt PCBs were applied in China, of which 179 t were PCB-153. By the end of 2005, most of them (56.4%) were emitted into the soil, 2.7% entered the air, and about 20.8% was sealed in storage site or still in service. Historical emissions exhibited increasing trends after 1968, 1984 and 1994, which were mainly associated with usage or disposal processes. Although primary emission has been declined since 2005, the influence of secondary emission from soils, unintentionally produced PCBs (UP-PCB), and reemission from storage sites could be a long-lasting issue in the future. This new emission inventory improves previous PCB emission inventory significantly, which underestimated PCB emission in China considerably.

Emission factor of ammonia (NH3) from on-road vehicles in China: tunnel tests in urban Guangzhou

NASA Astrophysics Data System (ADS)

Liu, Tengyu; Wang, Xinming; Wang, Boguang; Ding, Xiang; Deng, Wei; Lü, Sujun; Zhang, Yanli

2014-05-01

Ammonia (NH3) is the primary alkaline gas in the atmosphere that contributes to formation of secondary particles. Emission of NH3 from vehicles, particularly gasoline powered light duty vehicles equipped with three-way catalysts, is regarded as an important source apart from emissions from animal wastes and soils, yet measured emission factors for motor vehicles are still not available in China, where traffic-related emission has become an increasingly important source of air pollutants in urban areas. Here we present our tunnel tests for NH3 from motor vehicles under ‘real world conditions’ in an urban roadway tunnel in Guangzhou, a central city in the Pearl River Delta (PRD) region in south China. By attributing all NH3 emissions in the tunnel to light-duty gasoline vehicles, we obtained a fuel-based emission rate of 2.92 ± 0.18 g L-1 and a mileage-based emission factor of 229.5 ± 14.1 mg km-1. These emission factors were much higher than those measured in the United States while measured NO x emission factors (7.17 ± 0.60 g L-1 or 0.56 ± 0.05 g km-1) were contrastingly near or lower than those previously estimated by MOBILE/PART5 or COPERT IV models. Based on the NH3 emission factors from this study, on-road vehicles accounted for 8.1% of NH3 emissions in the PRD region in 2006 instead of 2.5% as estimated in a previous study using emission factors taken from the Emission Inventory Improvement Program (EIIP) in the United States.

The Influence of Fuelbed Physical Properties on Biomass Burning Emissions

NASA Astrophysics Data System (ADS)

Urbanski, S. P.; Lincoln, E.; Baker, S. P.; Richardson, M.

2014-12-01

Emissions from biomass fires can significantly degrade regional air quality and therefore are of major concern to air regulators and land managers in the U.S. and Canada. Accurately estimating emissions from different fire types in various ecosystems is crucial to predicting and mitigating the impact of fires on air quality. The physical properties of ecosystems' fuelbeds can heavily influence the combustion processes (e.g. flaming or smoldering) and the resultant emissions. However, despite recent progress in characterizing the composition of biomass smoke, significant knowledge gaps remain regarding the linkage between basic fuelbed physical properties and emissions. In laboratory experiments we examined the effects of fuelbed properties on combustion efficiency (CE) and emissions for an important fuel component of temperate and boreal forests - conifer needles. The bulk density (BD), depth (DZ), and moisture content (MC) of Ponderosa Pine needle fuelbeds were manipulated in 75 burns for which gas and particle emissions were measured. We found CE was negatively correlated with BD, DZ and MC and that the emission factors of species associated with smoldering combustion processes (CO, CH4, particles) were positively correlated with these fuelbed properties. The study indicates the physical properties of conifer needle fuelbeds have a significant effect on CE and hence emissions. However, many of the emission models used to predict and manage smoke impacts on air quality assume conifer litter burns by flaming combustion with a high CE and correspondingly low emissions of CO, CH4, particles, and organic compounds. Our results suggest emission models underestimate emissions from fires involving a large component of conifer needles. Additionally, our findings indicate that laboratory studies of emissions should carefully control fuelbed physical properties to avoid confounding effects that may obscure the effects being tested and lead to erroneous interpretations.

High-resolution inventory of technologies, activities, and emissions of coal-fired power plants in China from 1990 to 2010

NASA Astrophysics Data System (ADS)

Liu, F.; Zhang, Q.; Tong, D.; Zheng, B.; Li, M.; Huo, H.; He, K. B.

2015-07-01

This paper, which focuses on emissions from China's coal-fired power plants during 1990-2010, is the second in a series of papers that aims to develop high-resolution emission inventory for China. This is the first time that emissions from China's coal-fired power plants were estimated at unit level for a 20 year period. This inventory is constructed from a unit-based database compiled in this study, named the China coal-fired Power plant Emissions Database (CPED), which includes detailed information on the technologies, activity data, operation situation, emission factors, and locations of individual units and supplements with aggregated data where unit-based information is not available. Between 1990 and 2010, compared to a 479 % growth in coal consumption, emissions from China's coal-fired power plants increased by 56, 335 and 442 % for SO2, NOx and CO2, respectively, and decreased by 23 % for PM2.5. Driven by the accelerated economy growth, large power plants were constructed throughout the country after 2000, resulting in dramatic growth in emissions. Growth trend of emissions has been effective curbed since 2005 due to strengthened emission control measures including the installation of flue-gas desulfurization (FGD) systems and the optimization of the generation fleet mix by promoting large units and decommissioning small ones. Compared to previous emission inventories, CPED significantly improved the spatial resolution and temporal profile of power plant emission inventory in China by extensive use of underlying data at unit level. The new inventory developed in this study will enable a close examination for temporal and spatial variations of power plant emissions in China and will help to improve the performances of chemical transport models by providing more accurate emission data.

Methane emissions from the global oil and gas supply chain: recent advances and next steps

NASA Astrophysics Data System (ADS)

Zavala Araiza, D.; Herndon, S. C.; Roscioli, J. R.; Yacovitch, T. I.; Knighton, W. B.; Johnson, M.; Tyner, D. R.; Hamburg, S.

2017-12-01

A wide body of research has characterized methane emissions from the oil and gas system in the US. In contrast, empirical data is limited for other significant oil and gas producing regions across the world. As a consequence, measuring and characterizing methane emissions across global oil and gas operations will be crucial to the design of effective mitigation strategies. Several countries have announced pledges to reduce methane emissions from this system (e.g., North America, Climate and Clean Air Coalition [CCAC] ministers). In the case of Canada, the federal government recently announced regulations supporting a 40-45% reduction of methane emissions from the oil and gas production systems. For these regulations to be effective, it is critical to understand the current methane emission patterns. We present results from a coordinated multiscale (i.e., airborne-based, ground-based) measurement campaign in Alberta, Canada. We use empirically derived emission estimates to characterize site-level emissions and derive an emissions distribution. Our work shows that many major sources of emissions are unmeasured or underreported. Consistent with previous studies in the US, a small fraction of sites disproportionately account for the majority of emissions: roughly 20% of sites accounted for 75% of emissions. An independent airborne-based regional estimate was 40% lower than the ground-based regional estimate, but not statistically different. Finally, we summarize next steps as part of the CCAC Oil and Gas Methane Study: ongoing work that is targeting oil and gas sectors/production regions with limited empirical data on methane emissions. This work builds on the approach deployed in quantifying methane emissions from the oil and gas supply chain in the US, underscoring the commitment to transparency of the collected data, external review, deployment of multiple methodologies, and publication of results in peer-reviewed journals.

A PEMS study of the emissions of gaseous pollutants and ultrafine particles from gasoline- and diesel-fueled vehicles

NASA Astrophysics Data System (ADS)

Huang, Cheng; Lou, Diming; Hu, Zhiyuan; Feng, Qian; Chen, Yiran; Chen, Changhong; Tan, Piqiang; Yao, Di

2013-10-01

On-road emission measurements of gasoline- and diesel-fueled vehicles were conducted by a portable emission measurement system (PEMS) in Shanghai, China. Horiba OBS 2200 and TSI EEPS 3090 were employed to detect gaseous and ultrafine particle emissions during the tests. The driving-based emission factors of gaseous pollutants and particle mass and number were obtained on various road types. The average NOx emission factors of the diesel bus, diesel car, and gasoline car were 8.86, 0.68, and 0.17 g km-1, all of which were in excess of their emission limits. The particle number emission factors were 7.06 × 1014, 6.08 × 1014, and 1.57 × 1014 km-1, generally higher than the results for similar vehicle types reported in the previous studies. The size distributions of the particles emitted from the diesel vehicles were mainly concentrated in the accumulation mode, while those emitted from the gasoline car were mainly distributed in the nucleation mode. Both gaseous and particle emission rates exhibit significant correlations with the change in vehicle speed and power demand. The lowest emission rates for each vehicle type were produced during idling. The highest emission rates for each vehicle type were generally found in high-VSP bins. The particle number emission rates of the gasoline car show the strongest growth trend with increasing VSP and speed. The particle number emission for the gasoline car increased by 3 orders of magnitude from idling to the highest VSP and driving speed conditions. High engine power caused by aggressive driving or heavy loads is the main contributor to high emissions for these vehicles in real-world situations.

Effects of Biochar Addition on CO2 and N2O Emissions following Fertilizer Application to a Cultivated Grassland Soil

PubMed Central

Chen, Jingjing; Kim, Hyunjin; Yoo, Gayoung

2015-01-01

Carbon (C) sequestration potential of biochar should be considered together with emission of greenhouse gases when applied to soils. In this study, we investigated CO2 and N2O emissions following the application of rice husk biochars to cultivated grassland soils and related gas emissions tos oil C and nitrogen (N) dynamics. Treatments included biochar addition (CHAR, NO CHAR) and amendment (COMPOST, UREA, NO FERT). The biochar application rate was 0.3% by weight. The temporal pattern of CO2 emissions differed according to biochar addition and amendments. CO2 emissions from the COMPOST soils were significantly higher than those from the UREA and NO FERT soils and less CO2 emission was observed when biochar and compost were applied together during the summer. Overall N2O emission was significantly influenced by the interaction between biochar and amendments. In UREA soil, biochar addition increased N2O emission by 49% compared to the control, while in the COMPOST and NO FERT soils, biochar did not have an effect on N2O emission. Two possible mechanisms were proposed to explain the higher N2O emissions upon biochar addition to UREA soil than other soils. Labile C in the biochar may have stimulated microbial N mineralization in the C-limited soil used in our study, resulting in an increase in N2O emission. Biochar may also have provided the soil with the ability to retain mineral N, leading to increased N2O emission. The overall results imply that biochar addition can increase C sequestration when applied together with compost, and might stimulate N2O emission when applied to soil amended with urea. PMID:26020941

Odor and odorous chemical emissions from animal buildings: Part 4 - correlations between sensory and chemical measurements

USDA-ARS?s Scientific Manuscript database

This study supplemented the National Air Emissions Monitoring Study (NAEMS) by making comprehensive measurements, over a full calendar year, of odor emissions from five swine and four dairy rooms/buildings (subset of the total number of buildings monitored for the NAEMS project). The measurements ma...

CHARACTERIZATION OF THE FUGITIVE MERCURY EMISSIONS AT A CHLOR-ALKALI PLANT. OVERALL STUDY DESIGN

EPA Science Inventory

The paper discusses a detailed emissions measurement campaign that was conducted over a 9-day period within a mercury (Hg) cell chlor-alkali plant in the southeastern United States (U.S.). The principal focus of this study was to measure fugitive (non-ducted) airborne Hg emission...

Characterization of VOCs Emissions from Industrial Facilities and Natural Gas Production Sites: A Mobile Sensing Approach

NASA Astrophysics Data System (ADS)

Zhou, X.; Gu, J.; Trask, B.; Lyon, D. R.; Albertson, J. D.

2017-12-01

With the recent expansion of U.S. oil and gas (O&G) production, many studies have focused on the quantification of fugitive methane emissions. However, only a few studies have explored the emissions of volatile organic compounds (VOCs) from O&G production sites that affect human health in adjacent communities, both directly through exposure to toxic chemical compounds and indirectly via formation of ground-level ozone. In this study, we seek to quantify emissions of VOCs from O&G production sites and petrochemical facilities using a mobile sensing approach, with both high-end analyzers and relatively low-cost sensors. A probabilistic source characterization approach is used to estimate emission rates of VOCs, directly taking into account quantitative measure of sensor accuracy. This work will provide data with proper spatiotemporal resolution and coverage, so as to improve the understanding of VOCs emission from O&G production sites, VOCs-exposure of local communities, and explore the feasibility of low-cost sensors for VOCs monitoring. The project will provide an important foundational step to enable large scale studies.

Variability and uncertainty in life cycle assessment models for greenhouse gas emissions from Canadian oil sands production.

PubMed

Brandt, Adam R

2012-01-17

Because of interest in greenhouse gas (GHG) emissions from transportation fuels production, a number of recent life cycle assessment (LCA) studies have calculated GHG emissions from oil sands extraction, upgrading, and refining pathways. The results from these studies vary considerably. This paper reviews factors affecting energy consumption and GHG emissions from oil sands extraction. It then uses publicly available data to analyze the assumptions made in the LCA models to better understand the causes of variability in emissions estimates. It is found that the variation in oil sands GHG estimates is due to a variety of causes. In approximate order of importance, these are scope of modeling and choice of projects analyzed (e.g., specific projects vs industry averages); differences in assumed energy intensities of extraction and upgrading; differences in the fuel mix assumptions; treatment of secondary noncombustion emissions sources, such as venting, flaring, and fugitive emissions; and treatment of ecological emissions sources, such as land-use change-associated emissions. The GHGenius model is recommended as the LCA model that is most congruent with reported industry average data. GHGenius also has the most comprehensive system boundaries. Last, remaining uncertainties and future research needs are discussed.

Comparison of vehicle activity and emission inventory between Beijing and Shanghai.

PubMed

Liu, Huan; He, Kebin; Wang, Qidong; Huo, Hong; Lents, James; Davis, Nicole; Nikkila, Nick; Chen, Changhong; Osses, Mauricio; He, Chunyu

2007-10-01

Vehicle emission inventory is a critical element for air quality study. This study created systemic methods to establish a vehicle emission inventory in Chinese cities. The methods were used to obtain credible results of vehicle activity in Beijing and Shanghai. On the basis of the vehicle activity data, the International Vehicle Emission model is used to establish vehicle emission inventories. The emissions analysis indicates that 3 t of particulate matter (PM), 199 t of nitrogen oxides (NO(x)), 192 t of volatile organic compounds (VOCs), and 2403 t of carbon monoxide (CO) are emitted from on-road vehicles each day in Beijing, whereas 4 t of PM, 189 t of NO(x), 113 t of VOCs, and 1009 t of CO are emitted in Shanghai. Although common features were found in these two cities (many new passenger cars and a high taxi proportion in the fleet), the emission results are dissimilar because of the different local policy regarding vehicles. The method to quantify vehicle emission on an urban scale can be applied to other Chinese cities. Also, knowing how different policies can lead to diverse emissions is beneficial knowledge for other city governments.

Greenhouse Gas and Noxious Emissions from Dual Fuel Diesel and Natural Gas Heavy Goods Vehicles.

PubMed

Stettler, Marc E J; Midgley, William J B; Swanson, Jacob J; Cebon, David; Boies, Adam M

2016-02-16

Dual fuel diesel and natural gas heavy goods vehicles (HGVs) operate on a combination of the two fuels simultaneously. By substituting diesel for natural gas, vehicle operators can benefit from reduced fuel costs and as natural gas has a lower CO2 intensity compared to diesel, dual fuel HGVs have the potential to reduce greenhouse gas (GHG) emissions from the freight sector. In this study, energy consumption, greenhouse gas and noxious emissions for five after-market dual fuel configurations of two vehicle platforms are compared relative to their diesel-only baseline values over transient and steady state testing. Over a transient cycle, CO2 emissions are reduced by up to 9%; however, methane (CH4) emissions due to incomplete combustion lead to CO2e emissions that are 50-127% higher than the equivalent diesel vehicle. Oxidation catalysts evaluated on the vehicles at steady state reduced CH4 emissions by at most 15% at exhaust gas temperatures representative of transient conditions. This study highlights that control of CH4 emissions and improved control of in-cylinder CH4 combustion are required to reduce total GHG emissions of dual fuel HGVs relative to diesel vehicles.

Uncertainties of wild-land fires emission in AQMEII phase 2 case study

NASA Astrophysics Data System (ADS)

Soares, J.; Sofiev, M.; Hakkarainen, J.

2015-08-01

The paper discusses the main uncertainties of wild-land fire emission estimates used in the AQMEII-II case study. The wild-land fire emission of particulate matter for the summer fire season of 2010 in Eurasia was generated by the Integrated System for wild-land Fires (IS4FIRES). The emission calculation procedure included two steps: bottom-up emission compilation from radiative energy of individual fires observed by MODIS instrument on-board of Terra and Aqua satellites; and top-down calibration of emission factors based on the comparison between observations and modelled results. The approach inherits various uncertainties originating from imperfect information on fires, inaccuracies of the inverse problem solution, and simplifications in the fire description. These are analysed in regard to the Eurasian fires in 2010. It is concluded that the total emission is likely to be over-estimated by up to 50% with individual-fire emission accuracy likely to vary in a wide range. The first results of the new IS4FIRESv2 products and fire-resolving modelling are discussed in application to the 2010 events. It is shown that the new emission estimates have similar patterns but are lower than the IS4FIRESv1 values.

Evaluation of a Fuel-Based Oil and Gas Inventory of Nitrogen Oxides with Top-Down Emissions

NASA Astrophysics Data System (ADS)

Mcdonald, B. C.; Gorchov Negron, A.; McKeen, S. A.; Peischl, J.; Gilman, J.; Ahmadov, R.; Frost, G. J.; Ryerson, T. B.; Thompson, C. R.; Trainer, M.

2017-12-01

Several studies have highlighted overestimates in anthropogenic emissions of nitrogen oxides (NOx) for the U.S., with particular attention on the mobile source sector. In this study, we explore whether there could be overestimates in the emissions of NOx from oil and gas production regions. We construct a bottom-up inventory using publicly available fuel use records of the industry and emission factors reported in the literature. We compare both the NEI 2011 and the fuel-based inventory with top-down emission fluxes derived by aircraft and ground-based field measurement campaigns by NOAA that occurred in 2012-13, including for basins located in Uintah, Haynesville, Marcellus, and Fayetteville. Compared to the top-down fluxes, the NEI overestimates NOx by a factor of 2 across the four basins. However, the discrepancies are not uniform, reflecting variability in oil and gas engine activity and NOx emission factors. We explore this variability with our fuel-based inventory and perform a Monte Carlo analysis to assess uncertainties in emissions. We find that on average the fuel-based inventory improves the agreement with the top-down emissions, and that the top-down emissions are within the uncertainties of our analysis.

Russian anthropogenic black carbon: Emission reconstruction and Arctic black carbon simulation

DOE PAGES

Huang, Kan; Fu, Joshua S.; Prikhodko, Vitaly Y.; ...

2015-10-02

Development of reliable source emission inventories is needed to advance the understanding of the origin of Arctic haze using chemical transport modeling. This paper develops a regional anthropogenic black carbon (BC) emission inventory for the Russian Federation, the largest country by land area in the Arctic Council. Activity data from combination of local Russia information and international resources, emission factors based on either Russian documents or adjusted values for local conditions, and other emission source data are used to approximate the BC emissions. Emissions are gridded at a resolution of 0.1° × 0.1° and developed into a monthly temporal profile.more » Total anthropogenic BC emission of Russia in 2010 is estimated to be around 224 Gg. Gas flaring, a commonly ignored black carbon source, contributes a significant fraction of 36.2% to Russia's total anthropogenic BC emissions. Other sectors, i.e., residential, transportation, industry, and power plants, contribute 25.0%, 20.3%, 13.1%, and 5.4%, respectively. Three major BC hot spot regions are identified: the European part of Russia, the southern central part of Russia where human population densities are relatively high, and the Urals Federal District where Russia's major oil and gas fields are located but with sparse human population. BC simulations are conducted using the hemispheric version of Community Multi-scale Air Quality Model with emission inputs from a global emission database EDGAR (Emissions Database for Global Atmospheric Research)-HTAPv2 (Hemispheric Transport of Air Pollution) and EDGAR-HTAPv2 with its Russian part replaced by the newly developed Russian BC emissions, respectively. The simulation using the new Russian BC emission inventory could improve 30–65% of absorption aerosol optical depth measured at the AERONET sites in Russia throughout the whole year as compared to that using the default HTAPv2 emissions. At the four ground monitoring sites (Zeppelin, Barrow, Alert, and Tiksi) in the Arctic Circle, surface BC simulations are improved the most during the Arctic haze periods (October–March). The poor performance of Arctic BC simulations in previous studies may be partly ascribed to the Russian BC emissions built on out-of-date and/or missing information, which could result in biases to both emission rates and the spatial distribution of emissions. Finally, this study highlights that the impact of Russian emissions on the Arctic haze has likely been underestimated, and its role in the Arctic climate system needs to be reassessed. The Russian black carbon emission source data generated in this study can be obtained via http://abci.ornl.gov/download.shtml or http://acs.engr.utk.edu/Data.php.« less

Russian anthropogenic black carbon: Emission reconstruction and Arctic black carbon simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Kan; Fu, Joshua S.; Prikhodko, Vitaly Y.

Development of reliable source emission inventories is needed to advance the understanding of the origin of Arctic haze using chemical transport modeling. This paper develops a regional anthropogenic black carbon (BC) emission inventory for the Russian Federation, the largest country by land area in the Arctic Council. Activity data from combination of local Russia information and international resources, emission factors based on either Russian documents or adjusted values for local conditions, and other emission source data are used to approximate the BC emissions. Emissions are gridded at a resolution of 0.1° × 0.1° and developed into a monthly temporal profile.more » Total anthropogenic BC emission of Russia in 2010 is estimated to be around 224 Gg. Gas flaring, a commonly ignored black carbon source, contributes a significant fraction of 36.2% to Russia's total anthropogenic BC emissions. Other sectors, i.e., residential, transportation, industry, and power plants, contribute 25.0%, 20.3%, 13.1%, and 5.4%, respectively. Three major BC hot spot regions are identified: the European part of Russia, the southern central part of Russia where human population densities are relatively high, and the Urals Federal District where Russia's major oil and gas fields are located but with sparse human population. BC simulations are conducted using the hemispheric version of Community Multi-scale Air Quality Model with emission inputs from a global emission database EDGAR (Emissions Database for Global Atmospheric Research)-HTAPv2 (Hemispheric Transport of Air Pollution) and EDGAR-HTAPv2 with its Russian part replaced by the newly developed Russian BC emissions, respectively. The simulation using the new Russian BC emission inventory could improve 30–65% of absorption aerosol optical depth measured at the AERONET sites in Russia throughout the whole year as compared to that using the default HTAPv2 emissions. At the four ground monitoring sites (Zeppelin, Barrow, Alert, and Tiksi) in the Arctic Circle, surface BC simulations are improved the most during the Arctic haze periods (October–March). The poor performance of Arctic BC simulations in previous studies may be partly ascribed to the Russian BC emissions built on out-of-date and/or missing information, which could result in biases to both emission rates and the spatial distribution of emissions. Finally, this study highlights that the impact of Russian emissions on the Arctic haze has likely been underestimated, and its role in the Arctic climate system needs to be reassessed. The Russian black carbon emission source data generated in this study can be obtained via http://abci.ornl.gov/download.shtml or http://acs.engr.utk.edu/Data.php.« less

Ammonia and hydrogen sulfide emissions from swine production facilities in North America: a meta-analysis.

PubMed

Liu, Z; Powers, W; Murphy, J; Maghirang, R

2014-04-01

Literature on NH3 and H2S emissions from swine production facilities in North America was reviewed, and a meta-analysis was conducted on measured emissions data from swine houses and manure storage facilities as well as concentration data in the vicinity of swine production facilities. Results from more than 80 studies were compiled with results from the 11 swine sites in the National Air Emissions Monitoring Study (NAEMS). Data across studies were analyzed statistically using the MIXED procedures of SAS. The median emission rates from swine houses across various production stages and manure handling systems were 2.78 and 0.09 kg/yr per pig for NH3 and H2S, respectively. The median emission rates from swine storage facilities were 2.08 and 0.20 kg/yr per pig for NH3 and H2S, respectively. The size of swine farm that may trigger the need to report NH3 emissions under the Emergency Planning and Community Right-to-Know Act (EPCRA) is 3,410 pigs on the basis of the median NH3 emission rate (4.86 kg/yr per pig), but the threshold can be as low as 992 pigs on the basis of the 90th-percentile emission rates (16.71 kg/yr per pig). Swine hoop houses had significantly higher NH3 emission rate (14.80 kg/yr per pig) than other manure-handling systems (P < 0.01), whereas deep-pit houses had the highest H2S emission rate (16.03 kg/yr per pig, P = 0.03). Farrowing houses had the highest H2S emission rate (2.50 kg/yr per pig), followed by gestation houses, and finishing houses had the lowest H2S emission rate (P < 0.01). Regression models for NH3 and H2S emission rates were developed for finishing houses with deep pits, recharge pits, and lagoons. The NH3 emission rates increased with increasing air temperature, but effects of air temperature on H2S emission rates were not significant. The recharge interval of manure pits significantly affected H2S but not NH3 emission rates. The H2S emission rates were also influenced by the size of the operation. Although NH3 and H2S concentrations at the edge of swine houses or lagoons were often higher than corresponding acute or intermediate minimum risk levels (MRL), they decreased quickly to less than corresponding chronic or intermediate MRL as distances from emission sources increased. At the distances 30 to 1,185 m from emission sources, the average ambient concentrations for NH3 and H2S were 46 ± 46 µg/m(3) and 4.3 ± 8.6 µg/m(3) respectively.

Mars atmosphere studies with the OMEGA/Mars Express experiment: I. Overview and detection of lfuorescent emission by CO2

NASA Astrophysics Data System (ADS)

Drossart, P.; Combes, M.; Encrenaz, T.; Melchiorri, R.; Fouchet, T.; Forget, F.; Moroz, V.; Ignatiev, N.; Bibring, J.-P.; Langevin, Y.; OMEGA Team

Observations of Mars by the OMEGA/Mars Express experiment provide extended maps of the martian disk at all latitudes, and with various conditions of illumination, between 0.4 to 5 micron. The atmospheric investigations so far conducted by our team are focussed on the infrared part of the spectrum (1-5 micron), and include: the development of a correction algorithm for atmospheric gaseous absorption, to give access to fine mineralogic studies, largely decorrelated from atmospheric effects the study of dust opacity effects in the near infrared, with the aim to correct also the rough spectra from dust opacity perturbation the study of minor constituents like CO, to search for regional or global variations the study of CO2 emission at 4.3 micron related to fluorescent emission This last effect is prominently detected in limb observations obtained in 3-axis stabilized mode of Mars Express, with high altitude emission in the CO2 fundamental at 4.3 micron, usually seen in absorption in nadir observations. These emissions are related to non-LTE atmospheric layers, well above the solid surface in the mesosphere. Such emissions are also present in Earth and Venus limb observations. They are present also in nadir observations, but are reinforced in limb viewing geometry due to the tangential view. A numerical model of these emission will be presented.

Comparing emission rates derived from a model with a plume-based approach and quantifying the contribution of vehicle classes to on-road emissions and air quality.

PubMed

Xu, Junshi; Wang, Jonathan; Hilker, Nathan; Fallah-Shorshani, Masoud; Saleh, Marc; Tu, Ran; Wang, An; Minet, Laura; Stogios, Christos; Evans, Greg; Hatzopoulou, Marianne

2018-06-05

This study presents a comparison of fleet averaged emission factors (EFs) derived from a traffic emission model with EFs estimated using plume-based measurements, including an investigation of the contribution of vehicle classes to carbon monoxide (CO), nitrogen oxides (NO x ), and elemental carbon (EC) along an urban corridor. To this end, a field campaign was conducted over one week in June 2016 on an arterial road in Toronto, Canada. Traffic data were collected using a traffic camera and a radar, while air quality was characterized using two monitoring stations: one located at ground-level and another at the rooftop of a four-storey building. A traffic simulation model was calibrated and validated and sec-by-sec speed profiles for all vehicle trajectories were extracted to model emissions. In addition, dispersion modelling was conducted to identify the extent to which differences in emissions translate to differences in near-road concentrations. Our results indicate that modelled EFs for CO and NO x are twice as high as plume-based EFs. Besides, modelled results indicate that transit bus emissions accounted for 60% and 70% of the total emissions of NO x and EC. Transit bus emission rates in g/passenger.km for NO x and EC were up to 8 and 22 times the emission rates of passenger cars. In contrast, the Toronto streetcars, which are electrically fuelled, were found to improve near-road air quality despite their negative impact on traffic speeds. Finally, we observe that the difference in estimated concentrations derived from the two methods is not as large as the difference in estimated emissions due to the influence of meteorology and of the urban background given that the study network is located in a busy downtown area. Implications This study presents a comparison of fleet averaged emission factors (EFs) derived from a traffic emission model with EFs estimated using plume-based measurements, including an investigation of the contribution of vehicle classes to various pollutants. Besides, dispersion modelling was conducted to identify the extent to which differences in emissions translate to differences in near-road concentrations. We observe that the difference in estimated concentrations derived from the two methods is not as large as the difference in estimated emissions due to the influence of meteorology and of the urban background as the study network is located in a busy downtown area.

[Effect of Biochar on Soil Greenhouse Gas Emissions in Semi-arid Region].

PubMed

Guo, Yan-liang; Wang, Dan-dan; Zheng, Ji-yong; Zhao, Shi-wei; Zhang, Xing-chang

2015-09-01

This study aimed to investigate the effects of biochar addition on the emission of greenhouse gases from farmland soil in semi-arid region. Through an in-situ experiments, the influence of sawdust biochar(J) and locust tree skin biochar (H) at three doses (1%, 3%, and 5% of quality percentage) on C2, CH4 and N2O emissions were studied within the six months in the south of Ningxiaprovince. The results indicated that soil CO2 emission flux was slightly increased with the addition doses for both biochars, and the averaged CO2 emission flux for sawdust and locust tree skin biochar was enhanced by 1. 89% and 3. 34% compared to the control, but the difference between treatments was not statistically significant. The soil CH4 emission was decreased with the increasing of biochar doses, by 1. 17%, 2. 55%, 4. 32% for J1, J3, J5 and 2. 35%, 5. 83%, 7. 32% for H1, H3, H5, respectively. However, the difference was statistically significant only for J5, H3 and H5 treatments (P <0. 05). Across addition doses, there was no apparent effect on soil N2O emission. Our study indicated that the biochar has no significant influence on soil CO2 and N2O emissions within six months in semi-arid region and can significantly influence soil CH4 emissions (P < 0. 05). As for biochar type, the locust tree skin biochar is significantly better than the sawdust biochar in terms of restraining CH4 emission(P = 0. 048).

Assessment of Emerging Regional Air Quality (AQ) and Greenhouse Gas (GHG) Impacts and Potential Mitigation Strategies in U.S. Energy Sectors

NASA Astrophysics Data System (ADS)

Kinnon, Michael Mac

The current domestic reliance on high-emitting fossil fuels for energy needs is the key driver of U.S. greenhouse gas (GHG) and pollutant emissions driving both climate change and regional air quality (AQ) concerns. Moving forward, emission sources in U.S. energy sectors will be subjected to changes driven by numerous phenomena, including technology evolution, environmental impacts, sustainability goals, and socioeconomic factors. This evolution will directly affect emissions source-related impacts on regional AQ that effective emissions control strategies must account for, including relative source contributions. Though previous studies have evaluated the emissions and AQ impacts of different sectors, technologies and fuels, most previous studies have assessed emissions impacts only without using advanced atmospheric models to accurately account for both spatial and temporal emissions perturbations and atmospheric chemistry and transport. In addition, few previous studies have considered the integration of multiple technologies and fuels in different U.S. regions.. Finally, most studies do not project emissions several decades into the future to assess what sources should be targeted with priority over time. These aspects are critical for understanding how both emissions sources and potential mitigation strategies impact the formation and fate of primary and secondary pollutants, including ground-level ozone and particulate matter concentrations. Therefore, this work utilizes a set of modeling tools to project and then to spatially and temporally resolve emissions as input into a 3-D Eulerian AQ model to assess how sources of emissions contribute to future atmospheric pollutant burdens. Further, analyses of the potential impacts of alternative energy strategies contained in potential mitigation strategies are conducted for priority targets to develop an understanding of how to maximize AQ benefits and avoid unforeseen deleterious tradeoffs between GHG reduction and AQ. Findings include changes in the relative contribution to AQ that elevate the importance of addressing emissions from all sectors and sources including some that may be more difficult to control, including industry, petroleum refineries, and nonlight duty vehicle transportation sources. Additionally, mitigation strategies must consider the full range of life cycle and system effects in order to avoid AQ tradeoffs spatially and temporally.

Optical emission from a small scale model electric arc furnace in 250-600 nm region.

PubMed

Mäkinen, A; Niskanen, J; Tikkala, H; Aksela, H

2013-04-01

Optical emission spectroscopy has been for long proposed for monitoring and studying industrial steel making processes. Whereas the radiative decay of thermal excitations is always taking place in high temperatures needed in steel production, one of the most promising environment for such studies are electric arc furnaces, creating plasma in excited electronic states that relax with intense characteristic emission in the optical regime. Unfortunately, large industrial scale electric arc furnaces also present a challenging environment for optical emission studies and application of the method is not straightforward. To study the usability of optical emission spectroscopy in real electric arc furnaces, we have developed a laboratory scale DC electric arc furnace presented in this paper. With the setup, optical emission spectra of Fe, Cr, Cr2O3, Ni, SiO2, Al2O3, CaO, and MgO were recorded in the wavelength range 250-600 nm and the results were analyzed with the help of reference data. The work demonstrates that using characteristic optical emission, obtaining in situ chemical information from oscillating plasma of electric arc furnaces is indeed possible. In spite of complications, the method could possibly be applied to industrial scale steel making process in order to improve its efficiency.

User's guide: Minerals management service outer continental shelf activity database (moad). Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steiner, C.K.; Causley, M.C.; Yocke, M.A.

1994-04-01

The 1990 Clean Air Act Amendments require the Minerals Management Service (MMS) to conduct a research study to assess the potential onshore air quality impact from the development of outer continental shelf (OCS) petroleum resources in the Gulf of Mexico. The need for this study arises from concern about the cumulative impacts of current and future OCS emissions on ozone concentrations on nonattainment areas, particularly in Texas and Louisiana. To make quantitative assessments of these impacts, MMS has commissioned an air quality study which includes as a major component the development of a comprehensive emission inventory for photochemical grid modeling.more » The emission inventories prepared in this study include both onshore and offshore emissions. All relevant emissions from anthropogenic and biogenic sources are considered, with special attention focused on offshore anthropogenic sources, including OCS oil and gas production facilities, crew and supply vessels and helicopters serving OCS facilities, commercial shipping and fishing, recreational boating, intercoastal barge traffic and other sources located in the adjacent state waters. This document describes the database created during this study that contains the activity information collected for the development of the OCS platform, and crew/supply vessel and helicopter emission inventories.« less

Uncertainties and implications of applying aggregated data for spatial modelling of atmospheric ammonia emissions.

PubMed

Hellsten, S; Dragosits, U; Place, C J; Dore, A J; Tang, Y S; Sutton, M A

2018-05-09

Ammonia emissions vary greatly at a local scale, and effects (eutrophication, acidification) occur primarily close to sources. Therefore it is important that spatially distributed emission estimates are located as accurately as possible. The main source of ammonia emissions is agriculture, and therefore agricultural survey statistics are the most important input data to an ammonia emission inventory alongside per activity estimates of emission potential. In the UK, agricultural statistics are collected at farm level, but are aggregated to parish level, NUTS-3 level or regular grid resolution for distribution to users. In this study, the Modifiable Areal Unit Problem (MAUP), associated with such amalgamation, is investigated in the context of assessing the spatial distribution of ammonia sources for emission inventories. England was used as a test area to study the effects of the MAUP. Agricultural survey data at farm level (point data) were obtained under license and amalgamated to different areal units or zones: regular 1-km, 5-km, 10-km grids and parish level, before they were imported into the emission model. The results of using the survey data at different levels of amalgamation were assessed to estimate the effects of the MAUP on the spatial inventory. The analysis showed that the size and shape of aggregation zones applied to the farm-level agricultural statistics strongly affect the location of the emissions estimated by the model. If the zones are too small, this may result in false emission "hot spots", i.e., artificially high emission values that are in reality not confined to the zone to which they are allocated. Conversely, if the zones are too large, detail may be lost and emissions smoothed out, which may give a false impression of the spatial patterns and magnitude of emissions in those zones. The results of the study indicate that the MAUP has a significant effect on the location and local magnitude of emissions in spatial inventories where amalgamated, zonal data are used. Copyright © 2018 Elsevier Ltd. All rights reserved.

The dynamic relationship between structural change and CO2 emissions in Malaysia: a cointegrating approach.

PubMed

Ali, Wajahat; Abdullah, Azrai; Azam, Muhammad

2017-05-01

The current study investigates the dynamic relationship between structural changes, real GDP per capita, energy consumption, trade openness, population density, and carbon dioxide (CO 2 ) emissions within the EKC framework over a period 1971-2013. The study used the autoregressive distributed lagged (ARDL) approach to investigate the long-run relationship between the selected variables. The study also employed the dynamic ordinary least squared (DOLS) technique to obtain the robust long-run estimates. Moreover, the causal relationship between the variables is explored using the VECM Granger causality test. Empirical results reveal a negative relationship between structural change and CO 2 emissions in the long run. The results indicate a positive relationship between energy consumption, trade openness, and CO 2 emissions. The study applied the turning point formula of Itkonen (2012) rather than the conventional formula of the turning point. The empirical estimates of the study do not support the presence of the EKC relationship between income and CO 2 emissions. The Granger causality test indicates the presence of long-run bidirectional causality between energy consumption, structural change, and CO 2 emissions in the long run. Economic growth, openness to trade, and population density unidirectionally cause CO 2 emissions. These results suggest that the government should focus more on information-based services rather than energy-intensive manufacturing activities. The feedback relationship between energy consumption and CO 2 emissions suggests that there is an ominous need to refurbish the energy-related policy reforms to ensure the installations of some energy-efficient modern technologies.

Airborne measurements of isoprene and monoterpene emissions from southeastern U.S. forests.

PubMed

Yu, Haofei; Guenther, Alex; Gu, Dasa; Warneke, Carsten; Geron, Chris; Goldstein, Allen; Graus, Martin; Karl, Thomas; Kaser, Lisa; Misztal, Pawel; Yuan, Bin

2017-10-01

Isoprene and monoterpene emission rates are essential inputs for atmospheric chemistry models that simulate atmospheric oxidant and particle distributions. Process studies of the biochemical and physiological mechanisms controlling these emissions are advancing our understanding and the accuracy of model predictions but efforts to quantify regional emissions have been limited by a lack of constraints on regional distributions of ecosystem emission capacities. We used an airborne wavelet-based eddy covariance measurement technique to characterize isoprene and monoterpene fluxes with high spatial resolution during the 2013 SAS (Southeast Atmosphere Study) in the southeastern United States. The fluxes measured by direct eddy covariance were comparable to emissions independently estimated using an indirect inverse modeling approach. Isoprene emission factors based on the aircraft wavelet flux estimates for high isoprene chemotypes (e.g., oaks) were similar to the MEGAN2.1 biogenic emission model estimates for landscapes dominated by oaks. Aircraft flux measurement estimates for landscapes with fewer isoprene emitting trees (e.g., pine plantations), were about a factor of two lower than MEGAN2.1 model estimates. The tendency for high isoprene emitters in these landscapes to occur in the shaded understory, where light dependent isoprene emissions are diminished, may explain the lower than expected emissions. This result demonstrates the importance of accurately representing the vertical profile of isoprene emitting biomass in biogenic emission models. Airborne measurement-based emission factors for high monoterpene chemotypes agreed with MEGAN2.1 in landscapes dominated by pine (high monoterpene chemotype) trees but were more than a factor of three higher than model estimates for landscapes dominated by oak (relatively low monoterpene emitting) trees. This results suggests that unaccounted processes, such as floral emissions or light dependent monoterpene emissions, or vegetation other than high monoterpene emitting trees may be an important source of monoterpene emissions in those landscapes and should be identified and included in biogenic emission models. Copyright © 2017 Elsevier B.V. All rights reserved.

Impacts of transportation sector emissions on future U.S. air quality in a changing climate. Part I: Projected emissions, simulation design, and model evaluation.

PubMed

Campbell, Patrick; Zhang, Yang; Yan, Fang; Lu, Zifeng; Streets, David

2018-07-01

Emissions from the transportation sector are rapidly changing worldwide; however, the interplay of such emission changes in the face of climate change are not as well understood. This two-part study examines the impact of projected emissions from the U.S. transportation sector (Part I) on ambient air quality in the face of climate change (Part II). In Part I of this study, we describe the methodology and results of a novel Technology Driver Model (see graphical abstract) that includes 1) transportation emission projections (including on-road vehicles, non-road engines, aircraft, rail, and ship) derived from a dynamic technology model that accounts for various technology and policy options under an IPCC emission scenario, and 2) the configuration/evaluation of a dynamically downscaled Weather Research and Forecasting/Community Multiscale Air Quality modeling system. By 2046-2050, the annual domain-average transportation emissions of carbon monoxide (CO), nitrogen oxides (NO x ), volatile organic compounds (VOCs), ammonia (NH 3 ), and sulfur dioxide (SO 2 ) are projected to decrease over the continental U.S. The decreases in gaseous emissions are mainly due to reduced emissions from on-road vehicles and non-road engines, which exhibit spatial and seasonal variations across the U.S. Although particulate matter (PM) emissions widely decrease, some areas in the U.S. experience relatively large increases due to increases in ship emissions. The on-road vehicle emissions dominate the emission changes for CO, NO x , VOC, and NH 3 , while emissions from both the on-road and non-road modes have strong contributions to PM and SO 2 emission changes. The evaluation of the baseline 2005 WRF simulation indicates that annual biases are close to or within the acceptable criteria for meteorological performance in the literature, and there is an overall good agreement in the 2005 CMAQ simulations of chemical variables against both surface and satellite observations. Copyright © 2018 Elsevier Ltd. All rights reserved.

Premature deaths attributed to source-specific BC emissions in six urban US regions

NASA Astrophysics Data System (ADS)

Turner, Matthew D.; Henze, Daven K.; Capps, Shannon L.; Hakami, Amir; Zhao, Shunliu; Resler, Jaroslav; Carmichael, Gregory R.; Stanier, Charles O.; Baek, Jaemeen; Sandu, Adrian; Russell, Armistead G.; Nenes, Athanasios; Pinder, Rob W.; Napelenok, Sergey L.; Bash, Jesse O.; Percell, Peter B.; Chai, Tianfeng

2015-11-01

Recent studies have shown that exposure to particulate black carbon (BC) has significant adverse health effects and may be more detrimental to human health than exposure to PM2.5 as a whole. Mobile source BC emission controls, mostly on diesel-burning vehicles, have successfully decreased mobile source BC emissions to less than half of what they were 30 years ago. Quantification of the benefits of previous emissions controls conveys the value of these regulatory actions and provides a method by which future control alternatives could be evaluated. In this study we use the adjoint of the Community Multiscale Air Quality (CMAQ) model to estimate highly-resolved spatial distributions of benefits related to emission reductions for six urban regions within the continental US. Emissions from outside each of the six chosen regions account for between 7% and 27% of the premature deaths attributed to exposure to BC within the region. While we estimate that nonroad mobile and onroad diesel emissions account for the largest number of premature deaths attributable to exposure to BC, onroad gasoline is shown to have more than double the benefit per unit emission relative to that of nonroad mobile and onroad diesel. Within the region encompassing New York City and Philadelphia, reductions in emissions from large industrial combustion sources that are not classified as EGUs (i.e., non-EGU) are estimated to have up to triple the benefits per unit emission relative to reductions to onroad diesel sectors, and provide similar benefits per unit emission to that of onroad gasoline emissions in the region. While onroad mobile emissions have been decreasing in the past 30 years and a majority of vehicle emission controls that regulate PM focus on diesel emissions, our analysis shows the most efficient target for stricter controls is actually onroad gasoline emissions.

Airborne measurements of isoprene and monoterpene emissions from southeastern U.S. forests

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, Haofei; Guenther, Alex; Gu, Dasa

Isoprene and monoterpene emission rates are essential inputs for atmospheric chemistry models that simulate atmospheric oxidant and particle distributions. Process studies of the biochemical and physiological mechanisms controlling these emissions are advancing our understanding and the accuracy of model predictions but efforts to quantify regional emissions have been limited by a lack of constraints on regional distributions of ecosystem emission capacities. We used an airborne wavelet-based eddy covariance measurement technique to characterize isoprene and monoterpene fluxes with high spatial resolution during the 2013 SAS (Southeast Atmosphere Study) in the southeastern United States. The fluxes measured by direct eddy covariance weremore » comparable to emissions independently estimated using an indirect inverse modeling approach. Isoprene emission factors based on the aircraft wavelet flux estimates for high isoprene chemotypes (e.g., oaks) were similar to the MEGAN2.1 biogenic emission model estimates for landscapes dominated by oaks. Aircraft flux measurement estimates for landscapes with fewer isoprene emitting trees (e.g., pine plantations), were about a factor of two lower than MEGAN2.1 model estimates. The tendency for high isoprene emitters in these landscapes to occur in the shaded understory, where light dependent isoprene emissions are diminished, may explain the lower than expected emissions. This result demonstrates the importance of accurately representing the vertical profile of isoprene emitting biomass in biogenic emission models. Airborne measurement-based emission factors for high monoterpene chemotypes agreed with MEGAN2.1 in landscapes dominated by pine (high monoterpene chemotype) trees but were more than a factor of three higher than model estimates for landscapes dominated by oak (relatively low monoterpene emitting) trees. This results suggests that unaccounted processes, such as floral emissions or light dependent monoterpene emissions, or vegetation other than high monoterpene emitting trees may be an important source of monoterpene emissions in those landscapes and should be identified and included in biogenic emission models.« less

ANALYSIS OF MOTOR VEHICLE EMISSIONS IN A HOUSTON TUNNEL DURING THE TEXAS AIR QUALITY STUDY 2000

EPA Science Inventory

Measurements from a Houston tunnel were used to develop fuel consumption based emission factors for CO, NOx, and Non-Methane Organic Compound (NMOC) for on-road gasoline vehicles. The Houston NOx emission factor was at the low range of emission factors reported in previous (pr...

Variability of wildland fire emissions across the contiguous United States

Treesearch

YongQiang Liu

2004-01-01

This study analyzes spatial and temporal variability of emissions from wildland fires across the contiguous US. The emissions are estimates based on a recently constructed dataset of historical fire records collected by multiple US governlnental agencies. Both wildfire and prescribed fires have the highest emissions over the Pacific coastal states. Prescribed fire...

Field Emission Enhancement and the Field-Screening Effect Reduction using Carbon Nanopipettes as Cold Cathodes

NASA Astrophysics Data System (ADS)

Safir, Abdelilah; Mudd, David; Yazdanpanah, Mehdi; Dobrokhotov, Vladimir; Sumanasekera, Gamini; Cohn, Robert

2008-03-01

In this work, we report a recent experimental study of high emission current densities exceeding 10mA/cm^2 and breakdown electric field lower than 5Volts/μm from novel cold cathodes such as conical shaped carbon nanopipettes (CNP). CNP were grown by CVD on Pt wire and have apex as sharp as 10nm with length between 3-6μm. The emission experiments were conducted under vacuum in a scanning electron microscope for individual CNP and in a dedicated chamber for bulk samples. CNP's conical bases and low density contribute significantly to the reduction of the screening effect and to the field emission enhancement. The experimental value for the field enhancement factor, γ, was about 867. Comparing emission results taken from CNP and aligned multiwall carbon nanotubes (MWNT) show that the ratio between γCNP and γMWNT is ˜1.6 which contributes to the reduction of screening effect. The emission from multilayers of graphene was also studied. High emission current (20μA) demonstrates promising emission properties of graphene.

A hybrid method for provincial scale energy-related carbon emission allocation in China.

PubMed

Bai, Hongtao; Zhang, Yingxuan; Wang, Huizhi; Huang, Yanying; Xu, He

2014-01-01

Achievement of carbon emission reduction targets proposed by national governments relies on provincial/state allocations. In this study, a hybrid method for provincial energy-related carbon emissions allocation in China was developed to provide a good balance between production- and consumption-based approaches. In this method, provincial energy-related carbon emissions are decomposed into direct emissions of local activities other than thermal power generation and indirect emissions as a result of electricity consumption. Based on the carbon reduction efficiency principle, the responsibility for embodied emissions of provincial product transactions is assigned entirely to the production area. The responsibility for carbon generation during the production of thermal power is borne by the electricity consumption area, which ensures that different regions with resource endowments have rational development space. Empirical studies were conducted to examine the hybrid method and three indices, per capita GDP, resource endowment index and the proportion of energy-intensive industries, were screened to preliminarily interpret the differences among China's regional carbon emissions. Uncertainty analysis and a discussion of this method are also provided herein.

Particulate matter emissions from biochar-amended soils as a potential tradeoff to the negative emission potential

NASA Astrophysics Data System (ADS)

Ravi, Sujith; Sharratt, Brenton S.; Li, Junran; Olshevski, Stuart; Meng, Zhongju; Zhang, Jianguo

2016-10-01

Novel carbon sequestration strategies such as large-scale land application of biochar may provide sustainable pathways to increase the terrestrial storage of carbon. Biochar has a long residence time in the soil and hence comprehensive studies are urgently needed to quantify the environmental impacts of large-scale biochar application. In particular, black carbon emissions from soils amended with biochar may counteract the negative emission potential due to the impacts on air quality, climate, and biogeochemical cycles. We investigated, using wind tunnel experiments, the particulate matter emission potential of a sand and two agriculturally important soils amended with different concentrations of biochar, in comparison to control soils. Our results indicate that biochar application considerably increases particulate emissions possibly by two mechanisms-the accelerated emission of fine biochar particles and the generation and emission of fine biochar particles resulting from abrasion of large biochar particles by sand grains. Our study highlights the importance of considering the background soil properties (e.g., texture) and geomorphological processes (e.g., aeolian transport) for biochar-based carbon sequestration programs.

Effects of temperature on nitrous oxide (N2O) emission from intensive aquaculture system.

PubMed

Paudel, Shukra Raj; Choi, Ohkyung; Khanal, Samir Kumar; Chandran, Kartik; Kim, Sungpyo; Lee, Jae Woo

2015-06-15

This study examines the effects of temperature on nitrous oxide (N2O) emissions in a bench-scale intensive aquaculture system rearing Koi fish. The water temperature varied from 15 to 24 °C at interval of 3 °C. Both volumetric and specific rate for nitrification and denitrification declined as the temperature decreased. The concentrations of ammonia and nitrite, however, were lower than the inhibitory level for Koi fish regardless of temperature. The effects of temperature on N2O emissions were significant, with the emission rate and emission factor increasing from 1.11 to 1.82 mg N2O-N/d and 0.49 to 0.94 mg N2O-N/kg fish as the temperature decreased from 24 to 15 °C. A global map of N2O emission from aquaculture was established by using the N2O emission factor depending on temperature. This study demonstrates that N2O emission from aquaculture is strongly dependent on regional water temperatures as well as on fish production. Copyright © 2015 Elsevier B.V. All rights reserved.

Application of meta-omics techniques to understand greenhouse gas emissions originating from ruminal metabolism.

PubMed

Wallace, Robert J; Snelling, Timothy J; McCartney, Christine A; Tapio, Ilma; Strozzi, Francesco

2017-01-16

Methane emissions from ruminal fermentation contribute significantly to total anthropological greenhouse gas (GHG) emissions. New meta-omics technologies are beginning to revolutionise our understanding of the rumen microbial community structure, metabolic potential and metabolic activity. Here we explore these developments in relation to GHG emissions. Microbial rumen community analyses based on small subunit ribosomal RNA sequence analysis are not yet predictive of methane emissions from individual animals or treatments. Few metagenomics studies have been directly related to GHG emissions. In these studies, the main genes that differed in abundance between high and low methane emitters included archaeal genes involved in methanogenesis, with others that were not apparently related to methane metabolism. Unlike the taxonomic analysis up to now, the gene sets from metagenomes may have predictive value. Furthermore, metagenomic analysis predicts metabolic function better than only a taxonomic description, because different taxa share genes with the same function. Metatranscriptomics, the study of mRNA transcript abundance, should help to understand the dynamic of microbial activity rather than the gene abundance; to date, only one study has related the expression levels of methanogenic genes to methane emissions, where gene abundance failed to do so. Metaproteomics describes the proteins present in the ecosystem, and is therefore arguably a better indication of microbial metabolism. Both two-dimensional polyacrylamide gel electrophoresis and shotgun peptide sequencing methods have been used for ruminal analysis. In our unpublished studies, both methods showed an abundance of archaeal methanogenic enzymes, but neither was able to discriminate high and low emitters. Metabolomics can take several forms that appear to have predictive value for methane emissions; ruminal metabolites, milk fatty acid profiles, faecal long-chain alcohols and urinary metabolites have all shown promising results. Rumen microbial amino acid metabolism lies at the root of excessive nitrogen emissions from ruminants, yet only indirect inferences for nitrogen emissions can be drawn from meta-omics studies published so far. Annotation of meta-omics data depends on databases that are generally weak in rumen microbial entries. The Hungate 1000 project and Global Rumen Census initiatives are therefore essential to improve the interpretation of sequence/metabolic information.

Methane emissions in the Marcellus, top down constraints on emission growth with increasing production

NASA Astrophysics Data System (ADS)

DeCarlo, P. F.; Goetz, J. D.

2017-12-01

Emission inventories in the state of Pennsylvania are largely self-reported numbers by industry and significantly underestimate methane emissions at the facility level compared to measured emissions. Nevertheless, these emission inventories are used in making policy decisions at the state level with regard to reduction and mitigation of methane emissions from oil and gas development. A series of measurements made in northeastern Pennsylvania in 2012 and 2015 provide data for comparison to reported emission inventories at the facility level and changes in total emissions at the state and regional level. Tracer release studies performed in 2012 indicate up to an order of magnitude underestimate for facility level emissions. A novel methane background analysis on the 2012 and 2015 datasets indicates approximately a 300% increase in methane emissions over that three-year period scaling with increasing natural gas in the northeast region of Pennsylvania. State emission inventories indicate an 11% decrease over the same time period clearly at odds with the measurements. This presentation will also discuss potential areas of discrepancy with the emission inventories.

GEIA's Vision for Improved Emissions Information

NASA Astrophysics Data System (ADS)

Frost, G. J.; Granier, C.; Tarrason, L.; Middleton, P.

2014-12-01

Accurate, timely, and accessible emissions information is critical for understanding and making predictions about the atmosphere. We will present recent progress of the Global Emissions InitiAtive (GEIA, http://www.geiacenter.org/), a community-driven joint activity of IGAC, iLEAPS, and AIMES within the International Geosphere-Biosphere Programme. Since 1990, GEIA has served as a forum for the exchange of expertise and information on anthropogenic and natural emissions of trace gases and aerosols. GEIA supports a worldwide network of emissions data developers and users, providing a solid scientific foundation for atmospheric chemistry research. By the year 2020, GEIA envisions being a bridge between the environmental science, regulatory, assessment, policy, and operational communities. GEIA's core activities include 1) facilitating analysis that improves the scientific basis for emissions data, 2) enhancing access to emissions information, and 3) strengthening linkages within the international emissions community. We will highlight GEIA's current work distributing emissions data, organizing the development of new emissions datasets, facilitating regional emissions studies, and initiating analyses aimed at improving emissions information. GEIA welcomes new partnerships that advance emissions knowledge for the future.

Absorption and emission properties of photonic crystals and metamaterials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peng, Lili

We study the emission and absorption properties of photonic crystals and metamaterials using Comsol Multiphysics and Ansoft HFSS as simulation tools. We calculate the emission properties of metallic designs using drude model and the results illustrate that an appropriate termination of the surface of the metallic structure can significantly increase the absorption and therefore the thermal emissivity. We investigate the spontaneous emission rate modifications that occur for emitters inside two-dimensional photonic crystals and find the isotropic and directional emissions with respect to different frequencies as we have expected.

Virtual CO2 Emission Flows in the Global Electricity Trade Network.

PubMed

Qu, Shen; Li, Yun; Liang, Sai; Yuan, Jiahai; Xu, Ming

2018-06-05

Quantifying greenhouse gas emissions due to electricity consumption is crucial for climate mitigation in the electric power sector. Current practices primarily use production-based emission factors to quantify emissions for electricity consumption, assuming production and consumption of electricity take place within the same region. The increasingly intensified cross-border electricity trade complicates the accounting for emissions of electricity consumption. This study employs a network approach to account for the flows in the whole electricity trade network to estimate CO 2 emissions of electricity consumption for 137 major countries/regions in 2014. Results show that in some countries, especially those in Europe and Southern Africa, the impacts of electricity trade on the estimation of emission factors and embodied emissions are significant. The changes made to emission factors by considering intergrid electricity trade can have significant implications for emission accounting and climate mitigation when multiplied by total electricity consumption of the corresponding countries/regions.

Effects of phosphogypsum and superphosphate on compost maturity and gaseous emissions during kitchen waste composting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Fan; Beijing Municipal Research Institute of Environmental Protection, Beijing 100037; Li, Guoxue, E-mail: yangfan19870117@126.com

2015-02-15

Highlights: • Effect of phosphogypsum and superphosphate on composting gas emissions was studied. • The reduction mechanisms of composting gas were clarified in this study. • No negative effect was caused on maturity with phosphogypsum and superphosphate. • CH{sub 4} and NH{sub 3} emission was decreased with phosphogypsum and superphosphate addition. • GHG decreased by 17.4% and 7.3% with phosphogypsum and superphosphate addition. - Abstract: This study investigated the effects of phosphogypsum and superphosphate on the maturity and gaseous emissions of composting kitchen waste. Two amended compost treatments were conducted using phosphogypsum and superphosphate as additives with the addition ofmore » 10% of initial raw materials (dry weight). A control treatment was also studied. The treatments were conducted under aerobic conditions in 60-L reactors for 35 days. Maturity indexes were determined, and continuous measurements of CH{sub 4}, N{sub 2}O, and NH{sub 3} were taken. Phosphogypsum and superphosphate had no negative effects on compost maturity, although superphosphate inhibited the temperature rise in the first few days. The addition of phosphogypsum and superphosphate drastically reduced CH{sub 4} emissions (by 85.8% and 80.5%, respectively) and decreased NH{sub 3} emissions (by 23.5% and 18.9%, respectively). However, a slight increase in N{sub 2}O emissions (by 3.2% and 14.8%, respectively) was observed. Composting with phosphogypsum and superphosphate reduced total greenhouse gas emissions by 17.4% and 7.3% respectively.« less

Autonomous mobile platform for monitoring air emissions from industrial and municipal wastewater ponds.

PubMed

Fu, Long; Huda, Quamrul; Yang, Zheng; Zhang, Lucas; Hashisho, Zaher

2017-11-01

Significant amounts of volatile organic compounds and greenhouse gases are generated from wastewater lagoons and tailings ponds in Alberta, Canada. Accurate measurements of these air pollutants and greenhouse gases are needed to support management and regulatory decisions. A mobile platform was developed to measure air emissions from tailings pond in the oil sands region of Alberta. The mobile platform was tested in 2015 in a municipal wastewater treatment lagoon. With a flux chamber and a CO 2 /CH 4 sensor on board, the mobile platform was able to measure CO 2 and CH 4 emissions over two days at two different locations in the pond. Flux emission rates of CO 2 and CH 4 that were measured over the study period suggest the presence of aerobic and anaerobic zones in the wastewater treatment lagoon. The study demonstrated the capabilities of the mobile platform in measuring fugitive air emissions and identified the potential for the applications in air and water quality monitoring programs. The Mobile Platform demonstrated in this study has the ability to measure greenhouse gas (GHG) emissions from fugitive sources such as municipal wastewater lagoons. This technology can be used to measure emission fluxes from tailings ponds with better detection of spatial and temporal variations of fugitive emissions. Additional air and water sampling equipment could be added to the mobile platform for a broad range of air and water quality studies in the oil sands region of Alberta.

Study on emission characteristics of hybrid bus under driving cycles in typical Chinese city

NASA Astrophysics Data System (ADS)

Xie, Yongdong; Xu, Guangju

2017-09-01

In this study, hybrid city bus was taken as the research object, through the vehicle drum test, the vehicle emissions of hybrid bus, the transient emissions of gas pollutants, as well as the particle size and number distribution were surveyed. The results of the studies are listed as follows: First, compared to traditional fuel bus, hybrid bus could reduce about 44% of the NOx emissions, 33% of the total hydrocarbon emissions, and 51% of the particles emissions. Furthermore, the distribution of particles number concentration of test vehicle became high in middle and low in both sides. More specifically, the particle number concentration was mainly concentrated in the range from 0.021 to 0.755μm, the maximum was 0.2μm, and particle size of particulate matter (PM) less than 1.2μm accounted for 95% of the total number concentration. Particulate mass concentration was increased with increment of particle size, and the maximum of particulate mass (PM) concentration was 6.2μm. On average, whether traditional fuel bus or hybrid bus, the particle size of particulate matter(PM) less than 2.5μm accounted for more than 98% in the particles emission. It is found that the particles are more likely to deposit to the lung, respiratory bronchioles and alveoli, causing respiratory and lung diseases. Therefore, how to control the PM emissions of hybrid bus is the key factor of the study.

Improving the City-scale Emission Inventory of Anthropogenic Air Pollutants: A Case Study of Nanjing

NASA Astrophysics Data System (ADS)

Qiu, L.; Zhao, Y.; Xu, R.; Xie, F.; Wang, H.; Qin, H.; Wu, X.; Zhang, J.

2014-12-01

To evaluate the improvement of city-scale emission inventory, a high-resolution emission inventory of air pollutants for Nanjing is first developed combining detailed source information, and then justified through quantitative analysis with observations. The best available domestic emission factors and unit-/facility-based activity level data were compiled based on a thorough field survey on major emission sources. Totally 1089 individual emission sources were identified as point sources and all the emission-related parameters including burner type, combustion technology, fuel quality, and removal efficiency of pollution control devices, are carefully investigated and analyzed. Some new data such as detailed information of city fueling-gas stations, construction sites, monthly activity level, data from continuous emission monitoring systems and traffic flow information were combined to improve spatiotemporal distribution of this inventory. For SO2, NOX and CO, good spatial correlations were found between ground observation (9 state controlling air sampling sites in Nanjing) and city-scale emission inventory (R2=0.34, 0.38 and 0.74, respectively). For TSP, PM10 and PM2.5, however, poorer correlation was found due to relatively weaker accuracy in emission estimation and spatial distribution of road dust. The mixing ratios between specific pollutants including OC/EC, BC/CO and CO2/CO, are well correlated between those from ground observation and emission. Compared to MEIC (Multi-resolution Emission Inventory for China), there is a better spatial consistence between this city-scale emission inventory and NO2 measured by OMI (Ozone Monitoring Instrument). In particular, the city-scale emission inventory still correlated well with satellite observations (R2=0.28) while the regional emission inventory showed little correlation with satellite observations (R2=0.09) when grids containing power plants are excluded. It thus confirms the improvement of city-scale emission inventory on industrial and transportation sources other than big power plants. Through the inventory evaluation, the necessity to develop high-resolution emission inventory with comprehensive emission source information is revealed for atmospheric science studies and air quality improvement at local scale.

Estimated emissions of chlorofluorocarbons, hydrochlorofluorocarbons, and hydrofluorocarbons based on an interspecies correlation method in the Pearl River Delta region, China.

PubMed

Wu, Jing; Fang, Xuekun; Martin, Jonathan W; Zhai, Zihan; Su, Shenshen; Hu, Xia; Han, Jiarui; Lu, Sihua; Wang, Chen; Zhang, Jianbo; Hu, Jianxin

2014-02-01

Although many studies have been conducted in recent years on the emissions of chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and hydrofluorocarbons (HFCs) at the large regional (such as East Asia) and national scales, relatively few studies have been conducted for cities or metropolitan areas. In this study, 192 air samples were collected in the Pearl River Delta (PRD) region of China in November 2010. The atmospheric mixing ratios of six halocarbons were analyzed, including trichlorofluoromethane (CFC-11, CCl3F), dichlorodifluoromethane (CFC-12, CCl2F2), monochlorodifluoromethane (HCFC-22, CHClF2), 1,1-dichloro-1-fluoroethane (HCFC-141b, CH3CCl2F), 1-dichloro-1,1-fluoroethane (HCFC-142b, CH3CClF2), and 1,1,1,2-tetrafluoroethane (HFC-134a, CH2FCF3), and their emissions were estimated based on an interspecies correlation method using HCFC-22 as the reference species. The results showed no significant change in the regional concentration and emission of CFC in the past 10years, suggesting that the continuous regional emission of CFC has had no significant effect on the CFC regional concentration in the PRD region. Concentrations and emissions of HCFCs and HFCs are significantly higher compared to previous research in the PRD region (P<0.05). The largest emission was for HCFC-22, most likely due to its substitution for CFC-12 in the industrial and commercial refrigeration subsector, and the rapid development of the room air-conditioner and extruded polystyrene subsectors. The PRD's ODP-weighted emissions of the target HCFCs provided 9% (7-12%) of the national emissions for the corresponding species. The PRD's GWP-weighted emissions of the target HCFCs and HFC-134a account for 10% (7-12%) and 8% (7-9%), respectively, of the national emissions for the corresponding species, and thus are important contributions to China's total emissions. © 2013 Elsevier B.V. All rights reserved.

Analyzing source apportioned methane in northern California during Discover-AQ-CA using airborne measurements and model simulations

NASA Astrophysics Data System (ADS)

Johnson, Matthew S.; Yates, Emma L.; Iraci, Laura T.; Loewenstein, Max; Tadić, Jovan M.; Wecht, Kevin J.; Jeong, Seongeun; Fischer, Marc L.

2014-12-01

This study analyzes source apportioned methane (CH4) emissions and atmospheric mixing ratios in northern California during the Discover-AQ-CA field campaign using airborne measurement data and model simulations. Source apportioned CH4 emissions from the Emissions Database for Global Atmospheric Research (EDGAR) version 4.2 were applied in the 3-D chemical transport model GEOS-Chem and analyzed using airborne measurements taken as part of the Alpha Jet Atmospheric eXperiment over the San Francisco Bay Area (SFBA) and northern San Joaquin Valley (SJV). During the time period of the Discover-AQ-CA field campaign EDGAR inventory CH4 emissions were ∼5.30 Gg day-1 (Gg = 1.0 × 109 g) (equating to ∼1.90 × 103 Gg yr-1) for all of California. According to EDGAR, the SFBA and northern SJV region contributes ∼30% of total CH4 emissions from California. Source apportionment analysis during this study shows that CH4 mixing ratios over this area of northern California are largely influenced by global emissions from wetlands and local/global emissions from gas and oil production and distribution, waste treatment processes, and livestock management. Model simulations, using EDGAR emissions, suggest that the model under-estimates CH4 mixing ratios in northern California (average normalized mean bias (NMB) = -5.2% and linear regression slope = 0.20). The largest negative biases in the model were calculated on days when large amounts of CH4 were measured over local emission sources and atmospheric CH4 mixing ratios reached values >2.5 parts per million. Sensitivity emission studies conducted during this research suggest that local emissions of CH4 from livestock management processes are likely the primary source of the negative model bias. These results indicate that a variety, and larger quantity, of measurement data needs to be obtained and additional research is necessary to better quantify source apportioned CH4 emissions in California.

Analyzing Source Apportioned Methane in Northern California During DISCOVER-AQ-CA Using Airborne Measurements and Model Simulations

NASA Technical Reports Server (NTRS)

Johnson, Matthew S.

2014-01-01

This study analyzes source apportioned methane (CH4) emissions and atmospheric concentrations in northern California during the Discover-AQ-CA field campaign using airborne measurement data and model simulations. Source apportioned CH4 emissions from the Emissions Database for Global Atmospheric Research (EDGAR) version 4.2 were applied in the 3-D chemical transport model GEOS-Chem and analyzed using airborne measurements taken as part of the Alpha Jet Atmospheric eXperiment over the San Francisco Bay Area (SFBA) and northern San Joaquin Valley (SJV). During the time period of the Discover-AQ-CA field campaign EDGAR inventory CH4 emissions were 5.30 Gg/day (Gg 1.0 109 grams) (equating to 1.9 103 Gg/yr) for all of California. According to EDGAR, the SFBA and northern SJV region contributes 30 of total emissions from California. Source apportionment analysis during this study shows that CH4 concentrations over this area of northern California are largely influenced by global emissions from wetlands and local/global emissions from gas and oil production and distribution, waste treatment processes, and livestock management. Model simulations, using EDGAR emissions, suggest that the model under-estimates CH4 concentrations in northern California (average normalized mean bias (NMB) -5 and linear regression slope 0.25). The largest negative biases in the model were calculated on days when hot spots of local emission sources were measured and atmospheric CH4 concentrations reached values 3.0 parts per million (model NMB -10). Sensitivity emission studies conducted during this research suggest that local emissions of CH4 from livestock management processes are likely the primary source of the negative model bias. These results indicate that a variety, and larger quantity, of measurement data needs to be obtained and additional research is necessary to better quantify source apportioned CH4 emissions in California and further the understanding of the physical processes controlling them.

Surface emission determination of volatile organic compounds (VOC) from a closed industrial waste landfill using a self-designed static flux chamber.

PubMed

Gallego, E; Perales, J F; Roca, F J; Guardino, X

2014-02-01

Closed landfills can be a source of VOC and odorous nuisances to their atmospheric surroundings. A self-designed cylindrical air flux chamber was used to measure VOC surface emissions in a closed industrial landfill located in Cerdanyola del Vallès, Catalonia, Spain. The two main objectives of the study were the evaluation of the performance of the chamber setup in typical measurement conditions and the determination of the emission rates of 60 different VOC from that industrial landfill, generating a valuable database that can be useful in future studies related to industrial landfill management. Triplicate samples were taken in five selected sampling points. VOC were sampled dynamically using multi-sorbent bed tubes (Carbotrap, Carbopack X, Carboxen 569) connected to SKC AirCheck 2000 pumps. The analysis was performed by automatic thermal desorption coupled with a capillary gas chromatograph/mass spectrometry detector. The emission rates of sixty VOC were calculated for each sampling point in an effort to characterize surface emissions. To calculate average, minimum and maximum emission values for each VOC, the results were analyzed by three different methods: Global, Kriging and Tributary area. Global and Tributary area methodologies presented similar values, with total VOC emissions of 237 ± 48 and 222 ± 46 g day(-1), respectively; however, Kriging values were lower, 77 ± 17 gd ay(-1). The main contributors to the total emission rate were aldehydes (nonanal and decanal), acetic acid, ketones (acetone), aromatic hydrocarbons and alcohols. Most aromatic hydrocarbon (except benzene, naphthalene and methylnaphthalenes) and aldehyde emission rates exhibited strong correlations with the rest of VOC of their family, indicating a possible common source of these compounds. B:T ratio obtained from the emission rates of the studied landfill suggested that the factors that regulate aromatic hydrocarbon distributions in the landfill emissions are different from the ones from urban areas. Environmental conditions (atmospheric pressure, temperature and relative humidity) did not alter the pollutant emission fluxes. © 2013.

Soil invertebrate fauna affect N2 O emissions from soil.

PubMed

Kuiper, Imke; de Deyn, Gerlinde B; Thakur, Madhav P; van Groenigen, Jan Willem

2013-09-01

Nitrous oxide (N2 O) emissions from soils contribute significantly to global warming. Mitigation of N2 O emissions is severely hampered by a lack of understanding of its main controls. Fluxes can only partly be predicted from soil abiotic factors and microbial analyses - a possible role for soil fauna has until now largely been overlooked. We studied the effect of six groups of soil invertebrate fauna and tested the hypothesis that all of them increase N2 O emissions, although to different extents. We conducted three microcosm experiments with sandy soil and hay residue. Faunal groups included in our experiments were as follows: fungal-feeding nematodes, mites, springtails, potworms, earthworms and isopods. In experiment I, involving all six faunal groups, N2 O emissions declined with earthworms and potworms from 78.4 (control) to 37.0 (earthworms) or 53.5 (potworms) mg N2 O-N m(-2) . In experiment II, with a higher soil-to-hay ratio and mites, springtails and potworms as faunal treatments, N2 O emissions increased with potworms from 51.9 (control) to 123.5 mg N2 O-N m(-2) . Experiment III studied the effect of potworm density; we found that higher densities of potworms accelerated the peak of the N2 O emissions by 5 days (P < 0.001), but the cumulative N2 O emissions remained unaffected. We propose that increased soil aeration by the soil fauna reduced N2 O emissions in experiment I, whereas in experiment II N2 O emissions were driven by increased nitrogen and carbon availability. In experiment III, higher densities of potworms accelerated nitrogen and carbon availability and N2 O emissions, but did not increase them. Overall, our data show that soil fauna can suppress, increase, delay or accelerate N2 O emissions from soil and should therefore be an integral part of future N2 O studies. © 2013 John Wiley & Sons Ltd.

Analyzing source apportioned methane in northern California during Discover-AQ-CA using airborne measurements and model simulations

DOE PAGES

Johnson, Matthew S.; Yates, Emma L.; Iraci, Laura T.; ...

2014-12-01

This study analyzes source apportioned methane (CH 4) emissions and atmospheric mixing ratios in northern California during the Discover-AQ-CA field campaign using airborne measurement data and model simulations. Source apportioned CH 4 emissions from the Emissions Database for Global Atmospheric Research (EDGAR) version 4.2 were applied in the 3-D chemical transport model GEOS-Chem and analyzed using airborne measurements taken as part of the Alpha Jet Atmospheric eXperiment over the San Francisco Bay Area (SFBA) and northern San Joaquin Valley (SJV). During the time period of the Discover-AQ-CA field campaign EDGAR inventory CH 4 emissions were ~5.30 Gg day –1 (Ggmore » = 1.0 × 10 9 g) (equating to ~1.90 × 10 3 Gg yr –1) for all of California. According to EDGAR, the SFBA and northern SJV region contributes ~30% of total CH 4 emissions from California. Source apportionment analysis during this study shows that CH 4 mixing ratios over this area of northern California are largely influenced by global emissions from wetlands and local/global emissions from gas and oil production and distribution, waste treatment processes, and livestock management. Model simulations, using EDGAR emissions, suggest that the model under-estimates CH 4 mixing ratios in northern California (average normalized mean bias (NMB) = –5.2% and linear regression slope = 0.20). The largest negative biases in the model were calculated on days when large amounts of CH 4 were measured over local emission sources and atmospheric CH 4 mixing ratios reached values >2.5 parts per million. Sensitivity emission studies conducted during this research suggest that local emissions of CH 4 from livestock management processes are likely the primary source of the negative model bias. These results indicate that a variety, and larger quantity, of measurement data needs to be obtained and additional research is necessary to better quantify source apportioned CH 4 emissions in California.« less

Mercury emissions from industrial sources in India and its effects in the environment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arun B. Mukherjee; Prosun Bhattacharya; Atanu Sarkar

2009-07-01

This study describes the atmospheric mercury (Hg) emissions from industrial sources in India for the years 2000 to 2004. There is no consistent earlier information for Hg emissions to the environment for any sectors of industry. This paper may be the first road map in which we have tried to find out the total emission of Hg from a wide range of sources, e.g. from coal combustion to clinical thermometers broken during production or packing. There is a lack of basic data and in an attempt to correct this, emission factors suitable for Asian countries have been selected to completemore » this study. Before this document, there were some efforts in Europe to develop emission inventories for Hg from coal combustion or chlor-alkali plants for India. In this study it was found that total atmospheric emission from industrial sources has decreased from 321 Mg in 2000 to 253 Mg in 2004 due to a switch for the membrane cell process in the chlor-alkali industry. In 2004 the largest part of the Hg emissions stemmed from coal combustion in thermal power plants. Hg-cell technology had been used earlier in chlorine and sodium hydroxide production, as a result of which Hg concentration in terrestrial and aquatic species are nowadays quite high in coastal areas. India can thus be referred to as a mercury 'hot spot'. Limited information is available on emissions of Hg from industrial sources in India. Estimates are based on emission factors and the values taken from the literature. Against a background of limited data and information, this paper gives an overview of Hg emissions in India and of the recent steps undertaken by authorities to curb the emissions of Hg and its subsequent trans-boundary movement in the global environment.« less

Porous framework of T{sub 2}[Fe(CN){sub 6}].xH{sub 2}O with T=Co, Ni, Cu, Zn, and H{sub 2} storage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Avila, M.; Reguera, L.; Rodriguez-Hernandez, J.

2008-11-15

The materials under study were prepared from aqueous solutions of ferrocyanic acid and salts of the involved transition metals and their crystal structure solved and refined from X-ray powder diffraction data. Complementary information from thermogravimetric, infrared and Moessbauer data was also used for the structural study. Three different crystal structures were found: hexagonal (P-3) for Zn with the zinc atom coordinated to three N ends of CN groups plus a water molecule, cubic (Pm-3m) for Ni and Cu, and monoclinic (P2{sub 1}/m) for Co. For Ni and Cu the obtained solids have an open channel framework related to 50% ofmore » vacancies for the building unit, [Fe(CN){sub 6}]. In the as-synthesized material the framework free volume is occupied by coordinated and hydrogen-bonded water molecules. These of hexacyanoferrates (II) have received certain attention as prototype of materials for the hydrogen storage. In the anhydrous phase of Ni and Cu, 50% of the metal (T) coordination sites, located at the cavities surface, will be available to interact with the hydrogen molecule. However, when the crystal waters are removed the porous frameworks collapse as it is suggested by H{sub 2} and CO{sub 2} adsorption data. For Co, a structure of stacked layers was found where the cobalt atoms have both tetrahedral and octahedral coordination. The layers remain together through a network of hydrogen-bonding interactions between coordinated and weakly bonded water molecules. No H{sub 2} adsorption was observed in the anhydrous phase of Co. For Zn, the porous framework remains stable on the water removal but with a system of narrow channels and a small available volume, also inaccessible to H{sub 2}. - Graphical abstract: Structure of stacked layers for CO{sub 2}[Fe(CN){sub 6}].xH{sub 2}O.« less

Response of N2O emissions to biochar amendment in a cultivated sandy loam soil during freeze-thaw cycles

PubMed Central

Liu, Xiang; Wang, Quan; Qi, Zhiming; Han, Jiangang; Li, Lanhai

2016-01-01

In the last decade, an increasing number of studies have reported that soil nitrous oxide (N2O) emissions can be reduced by adding biochar. However, the effect of biochar amendment on soil N2O emissions during freeze-thaw cycle (FTC) is still unknown. In this laboratory study, biochar (0%, 2% and 4%, w/w) was added into a cultivated sandy loam soil and then treated with 15 times of FTC (each FTC consisted of freeze at −5/−10 °C for 24 h and thaw at 5/10 °C for 24 h), to test whether biochar can mitigate soil N2O emissions during FTC, and estimate the relationships between N2O emissions and soil inorganic nitrogen contents/microbial biomass content/enzyme activities. The results showed that biochar amendment suppressed soil N2O emissions by 19.9–69.9% as compared to soils without biochar amendment during FTC. However, N2O emissions were only significantly correlated to soil nitrate nitrogen (NO3−-N) contents, which decreased after biochar amendment, indicating that the decreased soil nitrification by adding biochar played an important role in mitigating N2O emissions during FTC. Further studies are needed to estimate the effectiveness of biochar amendment on reducing freeze-thaw induced N2O emissions from different soils under field conditions. PMID:27748462

Factors controlling nitrous oxide emissions from a full-scale activated sludge system in the tropics.

PubMed

Brotto, Ariane C; Kligerman, Débora C; Andrade, Samara A; Ribeiro, Renato P; Oliveira, Jaime L M; Chandran, Kartik; de Mello, William Z

2015-08-01

Despite interest in characterizing nitrous oxide (N2O) emissions from wastewater treatment plants (WWTPs) in several parts of the globe, there are few studies in tropical zones. This study focus on the contribution of the scientific knowledge of anthropogenic nitrogen greenhouse gas emissions to climate change in tropical countries, investigating factors controlling N2O emissions in a non-biological nitrogen removal municipal WWTP. In terms of operational parameters, dissolved oxygen (DO) concentrations displayed a biphasic impact on N2O production and emission, with the highest emission at DO of 2.0 mg O2 L(-1). The low solids retention time of 3 days also played a significant role, leading to nitrite accumulation, which is an important trigger for N2O production during nitrification. Furthermore, other factor especially important for tropical countries, namely, temperature, also had a positive correlation with N2O production. Emission factors estimated for this study were 0.12 (0.02-0.31)% of the influent total nitrogen load and 8.1 (3-17) g N2O person(-1) year(-1), 2.5 times higher than currently proposed emission factors. Therefore, the highly variability and dependence on operational parameters reinforce the use of a single emission factor is inadequate, especially for developing countries with limited or variable extent of biological wastewater treatment and in regions of the world with widely varying climate patterns.

Environmental and vegetation controls on the spatial variability of CH4 emission from wet-sedge and tussock tundra ecosystems in the Arctic.

PubMed

McEwing, Katherine Rose; Fisher, James Paul; Zona, Donatella

Despite multiple studies investigating the environmental controls on CH 4 fluxes from arctic tundra ecosystems, the high spatial variability of CH 4 emissions is not fully understood. This makes the upscaling of CH 4 fluxes from plot to regional scale, particularly challenging. The goal of this study is to refine our knowledge of the spatial variability and controls on CH 4 emission from tundra ecosystems. CH 4 fluxes were measured in four sites across a variety of wet-sedge and tussock tundra ecosystems in Alaska using chambers and a Los Gatos CO 2 and CH 4 gas analyser. All sites were found to be sources of CH 4 , with northern sites (in Barrow) showing similar CH 4 emission rates to the southernmost site (ca. 300 km south, Ivotuk). Gross primary productivity (GPP), water level and soil temperature were the most important environmental controls on CH 4 emission. Greater vascular plant cover was linked with higher CH 4 emission, but this increased emission with increased vascular plant cover was much higher (86 %) in the drier sites, than the wettest sites (30 %), suggesting that transport and/or substrate availability were crucial limiting factors for CH 4 emission in these tundra ecosystems. Overall, this study provides an increased understanding of the fine scale spatial controls on CH 4 flux, in particular the key role that plant cover and GPP play in enhancing CH 4 emissions from tundra soils.