Water and complex organic chemistry in the cold dark cloud Barnard 5: Observations and Models

NASA Astrophysics Data System (ADS)

Wirström, Eva; Charnley, Steven B.; Taquet, Vianney; Persson, Carina M.

2015-08-01

Studies of complex organic molecule (COM) formation have traditionally been focused on hot cores in regions of massive star formation, where chemistry is driven by the elevated temperatures - evaporating ices and allowing for endothermic reactions in the gas-phase. As more sensitive instruments have become available, the types of objects known to harbour COMs like acetaldehyde (CH3CHO), dimethyl ether (CH3OCH3), methyl formate (CH3OCHO), and ketene (CH2CO) have expanded to include low mass protostars and, recently, even pre-stellar cores. We here report on the first in a new category of objects harbouring COMs: the cold dark cloud Barnard 5 where non-thermal ice desorption induce complex organic chemistry entirely unrelated to local star-formation.Methanol, which only forms efficiently on the surfaces of dust grains, provide evidence of efficient non-thermal desorption of ices in the form of prominent emission peaks offset from protostellar activity and high density tracers in cold molecular clouds. A study with Herschel targeting such methanol emission peaks resulted in the first ever detection of gas-phase water offset from protostellar activity in a dark cloud, at the so called methanol hotspot in Barnard 5.To model the effect a transient injection of ices into the gas-phase has on the chemistry of a cold, dark cloud we have included gas-grain interactions in an existing gas-phase chemical model and connected it to a chemical reaction network updated and expanded to include the formation and destruction paths of the most common COMs. Results from this model will be presented.Ground-based follow-up studies toward the methanol hotspot in B5 have resulted in the detection of a number of COMs, including CH2CO, CH3CHO, CH3OCH3, and CH3OCHO, as well as deuterated methanol (CH2DOH). Observations have also confirmed that COM emission is extended and not localised to a core structure. The implications of these observational and theoretical studies of B5 will be discussed in the context of the gas-grain interaction in dark clouds and its relation to the chemistry of the earliest phases of low-mass star formation.

On the X-ray spectra of luminous, inhomogeneous accretion flows

NASA Astrophysics Data System (ADS)

Merloni, A.; Malzac, J.; Fabian, A. C.; Ross, R. R.

2006-08-01

We discuss the expected X-ray spectral and variability properties of black hole accretion discs at high luminosity, under the hypothesis that radiation-pressure-dominated discs are subject to violent clumping instabilities and, as a result, have a highly inhomogeneous two-phase structure. After deriving the full accretion disc solutions explicitly in terms of the parameters of the model, we study their radiative properties both with a simple two-zone model, treatable analytically, and with radiative transfer simulations which account simultaneously for energy balance and Comptonization in the hot phase, together with reflection, reprocessing, ionization and thermal balance in the cold phase. We show that, if not only the density, but also the heating rate within these flows is inhomogeneous, then complex reflection-dominated spectra can be obtained for a high enough covering fraction of the cold phase. In general, large reflection components in the observed X-ray spectra should be associated with strong soft excesses, resulting from the combined emission of ionized atomic emission lines. The variability properties of such systems are such that, even when contributing to a large fraction of the hard X-ray spectrum, the reflection component is less variable than the power-law-like emission originating from the hot Comptonizing phase, in agreement with what is observed in many Narrow Line Seyfert 1 galaxies and bright Seyfert 1. Our model falls within the family of those trying to explain the complex X-ray spectra of bright AGN with ionized reflection, but presents an alternative, specific, physically motivated, geometrical set-up for the complex multiphase structure of the inner regions of near-Eddington accretion flows.

Cold crucible induction melter test for crystalline ceramic waste form fabrication: A feasibility assessment

DOE PAGES

Amoroso, Jake W.; Marra, James; Dandeneau, Christopher S.; ...

2017-01-18

The first scaled proof-of-principle cold crucible induction melter (CCIM) test to process a multiphase ceramic waste form from a simulated combined (Cs/Sr, lanthanide and transition metal fission products) commercial used nuclear fuel waste stream was recently conducted in the United States. X-ray diffraction, 2-D X-ray absorption near edge structure (XANES), electron microscopy, inductively coupled plasma-atomic emission spectroscopy (and inductively coupled plasma-mass spectroscopy for Cs), and product consistency tests were used to characterize the fabricated CCIM material. Characterization analyses confirmed that a crystalline ceramic with a desirable phase assemblage was produced from a melt using a CCIM. We identified primary hollandite,more » pyrochlore/zirconolite, and perovskite phases in addition to minor phases rich in Fe, Al, or Cs. The material produced in the CCIM was chemically homogeneous and displayed a uniform phase assemblage with acceptable aqueous chemical durability.« less

40 CFR 86.1811-10 - Emission standards for light-duty vehicles, light-duty trucks and medium-duty passenger vehicles.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 25 2013 50 2014 75 2015 and subsequent 100 (4) Alternate phase-in schedules for cold temperature NMHC... 2012 2013 2009 2010 2011 2012 2013 2014 2010 2011 2012 2013 2014 2011 2012 2013 Table S10-5—In-Use Standards for Applicable Phase-In HLDT/MDPVs Model Year of Introduction 2010 2011 2012 2013 2014 2015 Models...

Impact of cold climates on vehicle emissions: the cold start air toxics pulse : final report.

DOT National Transportation Integrated Search

2016-09-21

This project measured cold start emissions from four vehicles in winter using fast response instrumentation to accurately measure the : time variation of the cold start emission pulse. Seventeen successful tests were conducted over a temperature rang...

40 CFR 1060.515 - How do I test EPA Nonroad Fuel Lines and EPA Cold-Weather Fuel Lines for permeation emissions?

Code of Federal Regulations, 2011 CFR

2011-07-01

... and EPA Cold-Weather Fuel Lines for permeation emissions? 1060.515 Section 1060.515 Protection of... Nonroad Fuel Lines and EPA Cold-Weather Fuel Lines for permeation emissions? Measure emission as follows for EPA Nonroad Fuel Lines and EPA Cold-Weather Fuel Lines: (a) Prior to permeation testing, use good...

40 CFR 1060.515 - How do I test EPA Nonroad Fuel Lines and EPA Cold-Weather Fuel Lines for permeation emissions?

Code of Federal Regulations, 2013 CFR

2013-07-01

... and EPA Cold-Weather Fuel Lines for permeation emissions? 1060.515 Section 1060.515 Protection of... Nonroad Fuel Lines and EPA Cold-Weather Fuel Lines for permeation emissions? Measure emission as follows for EPA Nonroad Fuel Lines and EPA Cold-Weather Fuel Lines: (a) Prior to permeation testing, use good...

40 CFR 1060.515 - How do I test EPA Nonroad Fuel Lines and EPA Cold-Weather Fuel Lines for permeation emissions?

Code of Federal Regulations, 2012 CFR

2012-07-01

... and EPA Cold-Weather Fuel Lines for permeation emissions? 1060.515 Section 1060.515 Protection of... Nonroad Fuel Lines and EPA Cold-Weather Fuel Lines for permeation emissions? Measure emission as follows for EPA Nonroad Fuel Lines and EPA Cold-Weather Fuel Lines: (a) Prior to permeation testing, use good...

40 CFR 1060.515 - How do I test EPA Nonroad Fuel Lines and EPA Cold-Weather Fuel Lines for permeation emissions?

Code of Federal Regulations, 2010 CFR

2010-07-01

... and EPA Cold-Weather Fuel Lines for permeation emissions? 1060.515 Section 1060.515 Protection of... Nonroad Fuel Lines and EPA Cold-Weather Fuel Lines for permeation emissions? Measure emission as follows for EPA Nonroad Fuel Lines and EPA Cold-Weather Fuel Lines: (a) Prior to permeation testing, use good...

40 CFR 1060.515 - How do I test EPA Nonroad Fuel Lines and EPA Cold-Weather Fuel Lines for permeation emissions?

Code of Federal Regulations, 2014 CFR

2014-07-01

... and EPA Cold-Weather Fuel Lines for permeation emissions? 1060.515 Section 1060.515 Protection of... Nonroad Fuel Lines and EPA Cold-Weather Fuel Lines for permeation emissions? Measure emission as follows for EPA Nonroad Fuel Lines and EPA Cold-Weather Fuel Lines: (a) Prior to permeation testing, use good...

MERCURY EMISSIONS FROM GASOLINE AND DIESEL POWERED ON-ROAD VEHICLES

EPA Science Inventory

Measurements of elemental gaseous mercury (Hg0), divalent reactive gaseous mercury (RGM), and particulate phase mercury (Hg(p)) were made from 14 gasoline and 2 diesel powered in-use light-duty vehicles on a chassis dynamometer. All vehicles were tested under both cold and hot st...

Oxidative potential of logwood and pellet burning particles assessed by a novel profluorescent nitroxide probe.

PubMed

Miljevic, B; Heringa, M F; Keller, A; Meyer, N K; Good, J; Lauber, A; Decarlo, P F; Fairfull-Smith, K E; Nussbaumer, T; Burtscher, H; Prevot, A S H; Baltensperger, U; Bottle, S E; Ristovski, Z D

2010-09-01

This study reports the potential toxicological impact of particles produced during biomass combustion by an automatic pellet boiler and a traditional logwood stove under various combustion conditions using a novel profluorescent nitroxide probe, BPEAnit. This probe is weakly fluorescent but yields strong fluorescence emission upon radical trapping or redox activity. Samples were collected by bubbling aerosol through an impinger containing BPEAnit solution, followed by fluorescence measurement. The fluorescence of BPEAnit was measured for particles produced during various combustion phases: at the beginning of burning (cold start), stable combustion after refilling with the fuel (warm start), and poor burning conditions. For particles produced by the logwood stove under cold-start conditions, significantly higher amounts of reactive species per unit of particulate mass were observed compared to emissions produced during a warm start. In addition, sampling of logwood burning emissions after passing through a thermodenuder at 250 degrees C resulted in an 80-100% reduction of the fluorescence signal of the BPEAnit probe, indicating that the majority of reactive species were semivolatile. Moreover, the amount of reactive species showed a strong correlation with the amount of particulate organic material. This indicates the importance of semivolatile organics in particle-related toxicity. Particle emissions from the pellet boiler, although of similar mass concentration, were not observed to lead to an increase in fluorescence signal during any of the combustion phases.

Field Emission Cold Cathode Devices Based on Eutectic Systems

DTIC Science & Technology

1981-07-01

8217RADC-TR-811-170 ’,Final Technical Report July 1981 FIELD EMISSION COLD CATHODE DEVICES BASED ON EUTECTIC SYSTEMS Fulmer Research Institute Ltd...and identify by block numrber) Field Emission Eutectic Systems Cold Cathode Rod Eutectics Electron Emitter Array Directionally Solidified Eutectics...Identify by block number) A survey has been made of the performance as field emission cold cathodes of selected refractory materials fabricated as

Field emission and photoluminescence characteristics of ZnS nanowires via vapor phase growth

NASA Astrophysics Data System (ADS)

Chang, Yongqin; Wang, Mingwei; Chen, Xihong; Ni, Saili; Qiang, Weijing

2007-05-01

Large-area ZnS nanowires were synthesized through a vapor phase deposition method. X-ray diffraction and electron microscopy results show that the products are composed of single crystalline ZnS nanowires with a cubic structure. The nanowires have sharp tips and are distributed uniformly on silicon substrates. The diameter of the bases is in the range of 320-530 nm and that of the tips is around 20-30 nm. The strong ultraviolet emission in the photoluminescence spectra also demonstrates that the ZnS nanowires are of high crystalline perfection. Field emission measurements reveal that the ZnS nanowires have a fairly low threshold field, which may be ascribed to their very sharp tips, rough surfaces and high crystal quality. The perfect field emission ability of the ZnS nanowires makes them a promising candidate for the fabrication of flexible cold cathodes.

Impact of cold temperature on Euro 6 passenger car emissions.

PubMed

Suarez-Bertoa, Ricardo; Astorga, Covadonga

2018-03-01

Hydrocarbons, CO, NOx, NH 3 , N 2 O, CO 2 and particulate matter emissions affect air quality, global warming and human health. Transport sector is an important source of these pollutants and high pollution episodes are often experienced during the cold season. However, EU vehicle emissions regulation at cold ambient temperature only addresses hydrocarbons and CO vehicular emissions. For that reason, we have studied the impact that cold ambient temperatures have on Euro 6 diesel and spark ignition (including: gasoline, ethanol flex-fuel and hybrid vehicles) vehicle emissions using the World-harmonized Light-duty Test Cycle (WLTC) at -7 °C and 23 °C. Results indicate that when facing the WLTC at 23 °C the tested vehicles present emissions below the values set for type approval of Euro 6 vehicles (still using NEDC), with the exception of NOx emissions from diesel vehicles that were 2.3-6 times higher than Euro 6 standards. However, emissions disproportionally increased when vehicles were tested at cold ambient temperature (-7 °C). High solid particle number (SPN) emissions (>1 × 10 11 # km -1 ) were measured from gasoline direct injection (GDI) vehicles and gasoline port fuel injection vehicles. However, only diesel and GDI SPN emissions are currently regulated. Results show the need for a new, technology independent, procedure that enables the authorities to assess pollutant emissions from vehicles at cold ambient temperatures. Harmful pollutant emissions from spark ignition and diesel vehicles are strongly and negatively affected by cold ambient temperatures. Only hydrocarbon, CO emissions are currently regulated at cold temperature. Therefore, it is of great importance to revise current EU winter vehicle emissions regulation. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

40 CFR 86.145-82 - Calculations; particulate emissions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... final reported test results for the mass particulate (Mp) in grams/mile shall be computed as follows. Mp = 0.43(Mp1 + Mp2)/(Dct + Ds) + 0.57(Mp3 + Mp2)/(Dht = Ds) where: (1) Mp1 = Mass of particulate...) for determination.) (2) Mp2 = Mass of particulate determined from the “stabilized” phase of the cold...

40 CFR 86.145-82 - Calculations; particulate emissions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... final reported test results for the mass particulate (Mp) in grams/mile shall be computed as follows. Mp = 0.43(Mp1 + Mp2)/(Dct + Ds) + 0.57(Mp3 + Mp2)/(Dht = Ds) where: (1) Mp1 = Mass of particulate...) for determination.) (2) Mp2 = Mass of particulate determined from the “stabilized” phase of the cold...

HIFI Spectroscopy of H2O Submillimeter Lines in Nuclei of Actively Star-forming Galaxies

NASA Astrophysics Data System (ADS)

Liu, L.; Weiß, A.; Perez-Beaupuits, J. P.; Güsten, R.; Liu, D.; Gao, Y.; Menten, K. M.; van der Werf, P.; Israel, F. P.; Harris, A.; Martin-Pintado, J.; Requena-Torres, M. A.; Stutzki, J.

2017-09-01

We present a systematic survey of multiple velocity-resolved H2O spectra using Herschel/Heterodyne Instrument for the Far Infrared (HIFI) toward nine nearby actively star-forming galaxies. The ground-state and low-excitation lines (E up ≤ 130 K) show profiles with emission and absorption blended together, while absorption-free medium-excitation lines (130 K ≤ E up ≤ 350 K) typically display line shapes similar to CO. We analyze the HIFI observation together with archival SPIRE/PACS H2O data using a state-of-the-art 3D radiative transfer code that includes the interaction between continuum and line emission. The water excitation models are combined with information on the dust and CO spectral line energy distribution to determine the physical structure of the interstellar medium (ISM). We identify two ISM components that are common to all galaxies: a warm ({T}{dust}˜ 40{--}70 K), dense (n({{H}})˜ {10}5{--}{10}6 {{cm}}-3) phase that dominates the emission of medium-excitation H2O lines. This gas phase also dominates the far-IR emission and the CO intensities for {J}{up}> 8. In addition, a cold ({T}{dust}˜ 20{--}30 K), dense (n({{H}})˜ {10}4{--}{10}5 {{cm}}-3), more extended phase is present. It outputs the emission in the low-excitation H2O lines and typically also produces the prominent line absorption features. For the two ULIRGs in our sample (Arp 220 and Mrk 231) an even hotter and more compact (R s ≤ 100 pc) region is present, which is possibly linked to AGN activity. We find that collisions dominate the water excitation in the cold gas and for lines with {E}{up}≤slant 300 K and {E}{up}≤slant 800 K in the warm and hot component, respectively. Higher-energy levels are mainly excited by IR pumping.

Development program on a cold cathode electron gun

NASA Technical Reports Server (NTRS)

Spindt, C. A.; Holland, C. E.

1985-01-01

During this phase of the cathode development program, SRI improved the multiple electron beam exposure system used to print hole patterns for the cathode arrays, studied anisotropic etch processes, conducted cathode investigations using an emission microscope, reviewed possible alternate materials for cathode fabrication, studied cathode storage techniques, conducted high power operation experiments, and demonstrated high-current-density operation with small arrays of tips.

Cold season emissions dominate the Arctic tundra methane budget

NASA Astrophysics Data System (ADS)

Zona, Donatella; Gioli, Beniamino; Commane, Róisín; Lindaas, Jakob; Wofsy, Steven C.; Miller, Charles E.; Dinardo, Steven J.; Dengel, Sigrid; Sweeney, Colm; Karion, Anna; Chang, Rachel Y.-W.; Henderson, John M.; Murphy, Patrick C.; Goodrich, Jordan P.; Moreaux, Virginie; Liljedahl, Anna; Watts, Jennifer D.; Kimball, John S.; Lipson, David A.; Oechel, Walter C.

2016-01-01

Arctic terrestrial ecosystems are major global sources of methane (CH4); hence, it is important to understand the seasonal and climatic controls on CH4 emissions from these systems. Here, we report year-round CH4 emissions from Alaskan Arctic tundra eddy flux sites and regional fluxes derived from aircraft data. We find that emissions during the cold season (September to May) account for ≥50% of the annual CH4 flux, with the highest emissions from noninundated upland tundra. A major fraction of cold season emissions occur during the "zero curtain" period, when subsurface soil temperatures are poised near 0 °C. The zero curtain may persist longer than the growing season, and CH4 emissions are enhanced when the duration is extended by a deep thawed layer as can occur with thick snow cover. Regional scale fluxes of CH4 derived from aircraft data demonstrate the large spatial extent of late season CH4 emissions. Scaled to the circumpolar Arctic, cold season fluxes from tundra total 12 ± 5 (95% confidence interval) Tg CH4 y-1, ∼25% of global emissions from extratropical wetlands, or ∼6% of total global wetland methane emissions. The dominance of late-season emissions, sensitivity to soil environmental conditions, and importance of dry tundra are not currently simulated in most global climate models. Because Arctic warming disproportionally impacts the cold season, our results suggest that higher cold-season CH4 emissions will result from observed and predicted increases in snow thickness, active layer depth, and soil temperature, representing important positive feedbacks on climate warming.

Cold season emissions dominate the Arctic tundra methane budget.

PubMed

Zona, Donatella; Gioli, Beniamino; Commane, Róisín; Lindaas, Jakob; Wofsy, Steven C; Miller, Charles E; Dinardo, Steven J; Dengel, Sigrid; Sweeney, Colm; Karion, Anna; Chang, Rachel Y-W; Henderson, John M; Murphy, Patrick C; Goodrich, Jordan P; Moreaux, Virginie; Liljedahl, Anna; Watts, Jennifer D; Kimball, John S; Lipson, David A; Oechel, Walter C

2016-01-05

Arctic terrestrial ecosystems are major global sources of methane (CH4); hence, it is important to understand the seasonal and climatic controls on CH4 emissions from these systems. Here, we report year-round CH4 emissions from Alaskan Arctic tundra eddy flux sites and regional fluxes derived from aircraft data. We find that emissions during the cold season (September to May) account for ≥ 50% of the annual CH4 flux, with the highest emissions from noninundated upland tundra. A major fraction of cold season emissions occur during the "zero curtain" period, when subsurface soil temperatures are poised near 0 °C. The zero curtain may persist longer than the growing season, and CH4 emissions are enhanced when the duration is extended by a deep thawed layer as can occur with thick snow cover. Regional scale fluxes of CH4 derived from aircraft data demonstrate the large spatial extent of late season CH4 emissions. Scaled to the circumpolar Arctic, cold season fluxes from tundra total 12 ± 5 (95% confidence interval) Tg CH4 y(-1), ∼ 25% of global emissions from extratropical wetlands, or ∼ 6% of total global wetland methane emissions. The dominance of late-season emissions, sensitivity to soil environmental conditions, and importance of dry tundra are not currently simulated in most global climate models. Because Arctic warming disproportionally impacts the cold season, our results suggest that higher cold-season CH4 emissions will result from observed and predicted increases in snow thickness, active layer depth, and soil temperature, representing important positive feedbacks on climate warming.

Cold season emissions dominate the Arctic tundra methane budget

PubMed Central

Zona, Donatella; Gioli, Beniamino; Lindaas, Jakob; Wofsy, Steven C.; Miller, Charles E.; Dinardo, Steven J.; Dengel, Sigrid; Sweeney, Colm; Karion, Anna; Chang, Rachel Y.-W.; Henderson, John M.; Murphy, Patrick C.; Goodrich, Jordan P.; Moreaux, Virginie; Liljedahl, Anna; Watts, Jennifer D.; Kimball, John S.; Lipson, David A.; Oechel, Walter C.

2016-01-01

Arctic terrestrial ecosystems are major global sources of methane (CH4); hence, it is important to understand the seasonal and climatic controls on CH4 emissions from these systems. Here, we report year-round CH4 emissions from Alaskan Arctic tundra eddy flux sites and regional fluxes derived from aircraft data. We find that emissions during the cold season (September to May) account for ≥50% of the annual CH4 flux, with the highest emissions from noninundated upland tundra. A major fraction of cold season emissions occur during the “zero curtain” period, when subsurface soil temperatures are poised near 0 °C. The zero curtain may persist longer than the growing season, and CH4 emissions are enhanced when the duration is extended by a deep thawed layer as can occur with thick snow cover. Regional scale fluxes of CH4 derived from aircraft data demonstrate the large spatial extent of late season CH4 emissions. Scaled to the circumpolar Arctic, cold season fluxes from tundra total 12 ± 5 (95% confidence interval) Tg CH4 y−1, ∼25% of global emissions from extratropical wetlands, or ∼6% of total global wetland methane emissions. The dominance of late-season emissions, sensitivity to soil environmental conditions, and importance of dry tundra are not currently simulated in most global climate models. Because Arctic warming disproportionally impacts the cold season, our results suggest that higher cold-season CH4 emissions will result from observed and predicted increases in snow thickness, active layer depth, and soil temperature, representing important positive feedbacks on climate warming. PMID:26699476

Cold season emissions dominate the Arctic tundra methane budget

DOE PAGES

Zona, Donatella; Gioli, Beniamino; Commane, Róisín; ...

2015-12-22

Arctic terrestrial ecosystems are major global sources of methane (CH 4); hence, it is important to understand the seasonal and climatic controls on CH 4 emissions from these systems. Here, we report year-round CH 4 emissions from Alaskan Arctic tundra eddy flux sites and regional fluxes derived from aircraft data. We find that emissions during the cold season (September to May) account for ≥ 50% of the annual CH 4 flux, with the highest emissions from noninundated upland tundra. A major fraction of cold season emissions occur during the “zero curtain” period, when subsurface soil temperatures are poised near 0more » °C. The zero curtain may persist longer than the growing season, and CH 4 emissions are enhanced when the duration is extended by a deep thawed layer as can occur with thick snow cover. Regional scale fluxes of CH 4 derived from aircraft data demonstrate the large spatial extent of late season CH 4 emissions. Scaled to the circumpolar Arctic, cold season fluxes from tundra total 12 ± 5 (95% confidence interval) Tg CH 4 y –1, ~25% of global emissions from extratropical wetlands, or ~6% of total global wetland methane emissions. Here, the dominance of late-season emissions, sensitivity to soil environmental conditions, and importance of dry tundra are not currently simulated in most global climate models. Because Arctic warming disproportionally impacts the cold season, our results suggest that higher cold-season CH 4 emissions will result from observed and predicted increases in snow thickness, active layer depth, and soil temperature, representing important positive feedbacks on climate warming.« less

Variable Cold-Induced Brown Adipose Tissue Response to Thyroid Hormone Status

PubMed Central

Hasselgren, Per-Olof; Glasgow, Allison; Doyle, Ashley N.; Lee, Alice J.; Fox, Peter; Gautam, Shiva; Hennessey, James V.; Kolodny, Gerald M.

2017-01-01

Background: In addition to its role in adaptive thermogenesis, brown adipose tissue (BAT) may protect from weight gain, insulin resistance/diabetes, and metabolic syndrome. Prior studies have shown contradictory results regarding the influence of thyroid hormone (TH) levels on BAT volume and activity. The aim of this pilot study was to gain further insights regarding the effect of TH treatment on BAT function in adult humans by evaluating the BAT mass and activity prospectively in six patients, first in the hypothyroid and then in the thyrotoxic phase. Methods: The study subjects underwent 18F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) scanning after cold exposure to measure BAT mass and activity while undergoing treatment for differentiated thyroid cancer, first while hypothyroid following TH withdrawal at the time of the radioactive iodine treatment and then three to six months after starting TH suppressive treatment when they were iatrogenically thyrotoxic. Thermogenic and metabolic parameters were measured in both phases. Results: All study subjects had detectable BAT under cold stimulation in both the hypothyroid and thyrotoxic state. The majority but not all (4/6) subjects showed an increase in detectable BAT volume and activity under cold stimulation between the hypothyroid and thyrotoxic phase (total BAT volume: 72.0 ± 21.0 vs. 87.7 ± 16.5 mL, p = 0.25; total BAT activity 158.1 ± 72.8 vs. 189.0 ± 55.5 SUV*g/mL, p = 0.34). Importantly, circulating triiodothyronine was a stronger predictor of energy expenditure changes compared with cold-induced BAT activity. Conclusions: Iatrogenic hypothyroidism lasting two to four weeks does not prevent cold-induced BAT activation, while the use of TH to induce thyrotoxicosis does not consistently increase cold-induced BAT activity. It remains to be determined which physiological factors besides TH play a role in regulating BAT function. PMID:27750020

Variable Cold-Induced Brown Adipose Tissue Response to Thyroid Hormone Status.

PubMed

Gavrila, Alina; Hasselgren, Per-Olof; Glasgow, Allison; Doyle, Ashley N; Lee, Alice J; Fox, Peter; Gautam, Shiva; Hennessey, James V; Kolodny, Gerald M; Cypess, Aaron M

2017-01-01

In addition to its role in adaptive thermogenesis, brown adipose tissue (BAT) may protect from weight gain, insulin resistance/diabetes, and metabolic syndrome. Prior studies have shown contradictory results regarding the influence of thyroid hormone (TH) levels on BAT volume and activity. The aim of this pilot study was to gain further insights regarding the effect of TH treatment on BAT function in adult humans by evaluating the BAT mass and activity prospectively in six patients, first in the hypothyroid and then in the thyrotoxic phase. The study subjects underwent 18F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) scanning after cold exposure to measure BAT mass and activity while undergoing treatment for differentiated thyroid cancer, first while hypothyroid following TH withdrawal at the time of the radioactive iodine treatment and then three to six months after starting TH suppressive treatment when they were iatrogenically thyrotoxic. Thermogenic and metabolic parameters were measured in both phases. All study subjects had detectable BAT under cold stimulation in both the hypothyroid and thyrotoxic state. The majority but not all (4/6) subjects showed an increase in detectable BAT volume and activity under cold stimulation between the hypothyroid and thyrotoxic phase (total BAT volume: 72.0 ± 21.0 vs. 87.7 ± 16.5 mL, p = 0.25; total BAT activity 158.1 ± 72.8 vs. 189.0 ± 55.5 SUV*g/mL, p = 0.34). Importantly, circulating triiodothyronine was a stronger predictor of energy expenditure changes compared with cold-induced BAT activity. Iatrogenic hypothyroidism lasting two to four weeks does not prevent cold-induced BAT activation, while the use of TH to induce thyrotoxicosis does not consistently increase cold-induced BAT activity. It remains to be determined which physiological factors besides TH play a role in regulating BAT function.

Powerful Radio Galaxies with Simbol-X: the Nuclear Environment

NASA Astrophysics Data System (ADS)

Torresi, E.; Grandi, P.; Malaguti, G.; Palumbo, G. G. C.; Bianchin, V.

2009-05-01

Fanaroff & Riley type II radio galaxies (FRII) are complex objects. In particular FRII Narrow Line Radio Galaxies (NLRG), optically classified as High Excitation Galaxies (HEG) show X-ray spectra very similar to their radio-quiet counterparts, the Seyfert 2 galaxies. They show 2-10 keV continua heavily obscured (NH~1023-24 cm-2) and intense FeKα lines, typical cold matter reprocessing features. Moreover recent Chandra and XMM-Newton observations suggest that the soft X-ray emission of HEG and Seyfert 2 have a common origin from photoionized gas, reinforcing the idea that not only their nuclear engine but also the circumnuclear gas (at least the warm phase) are similar. On the contrary, our knowledge of NLRG HEG above 10 keV is very poor when compared to brighter Seyfert 2. As a consequence, the physical properties of the cold phase of the circumnuclear gas (possibly linked to a dusty torus) are largely unknown. Thanks to its high sensitivity up to 80 keV, Simbol-X will provide very accurate spectra and will allow a direct comparison between the NLRG and Seyfert 2 cold environments.

SPECIATED VOC EMISSIONS FROM MODERN GDI LIGHT ...

EPA Pesticide Factsheets

Chassis dynamometer emissions testing was conducted to characterize speciated volatile organic compounds (VOCs), including mobile source air toxics (MSATs) and ozone precursors, in exhaust emissions from three modern gasoline direct injection (GDI) light-duty vehicles. Each GDI vehicle tested in this study utilized slightly different fuel injection technology: Vehicle 1 used a 2.4 liter, naturally aspirated, wall-guided GDI; Vehicle 2 used a 1.8 liter, turbocharged GDI engine; Vehicle 3 used a 1.5 liter, turbocharged, spray-guided GDI engine. Vehicle testing was conducted in a temperature controlled chassis dynamometer test cell at 22 °C over the EPA Federal Test Procedure (FTP) and a portion of the Supplemental FTP (SFTP). The FTP was conducted as a three phase cycle with a cold start, hot transient, and warm start phase (also known as the FTP-75 driving cycle). The SFTP consisted of the US06 driving cycle (conducted without the vehicle’s air conditioning on), which provides a more aggressive driving pattern than the FTP. The vehicles operated on 10 percent ethanol blended gasoline (E10). VOC emissions from diluted vehicle exhaust were sampled over each FTP phase and over the Supplemental FTP with SUMMA canisters for EPA Method TO-15 analysis and with DNPH cartridges for carbonyl analysis by EPA Method TO-11A. This presentation will report the impact of driving cycle and GDI technology on speciated MSAT emissions. MSAT emission rates will be compared

Electrostatic emissions between electron gyroharmonics in the outer magnetosphere

NASA Technical Reports Server (NTRS)

Hubbard, R. F.; Birmingham, T. J.

1977-01-01

A scheme was constructed and a theoretical model was developed to classify electrostatic emissions. All of the emissions appear to be generated by the same basic mechanism: an unstable electron plasma distribution consisting of cold electrons (less than 100 eV) and hot loss cone electrons (about 1 keV). Each emission class is associated with a particular range of model parameters; the wide band electric field data can thus be used to infer the density and temperature of the cold plasma component. The model predicts that gyroharmonic emissions near the plasma frequency require large cold plasma densities.

Methane, benzene and alkyl benzene cold start emission data of gasoline-driven passenger cars representing the vehicle technology of the last two decades

NASA Astrophysics Data System (ADS)

Heeb, Norbert V.; Forss, Anna-Maria; Saxer, Christian J.; Wilhelm, Patrick

The US urban driving cycle (FTP-75) is widely used to estimate both the emissions under hot engine conditions as well as those associated with the cold start. Applying fast analysis techniques such as chemical ionization mass spectrometry (CI-MS) the warm-up behavior of individual vehicles can be monitored at a time resolution of 1 s. CI-MS has been used to investigate the emissions of methane, benzene and the alkyl benzene class of compounds. The amount of the emissions at cold start influence was deduced from the time-resolved emission data of four gasoline-driven vehicle classes representing the vehicle technology of the last two decades. Overall, the emissions of five EURO-0, 20 EURO-1, 18 EURO-2 and so far of six EURO-3 passenger cars were recorded. The test vehicles were selected from the currently operating Swiss car fleet based on the car sales statistics. The average methane, benzene and alkyl benzene cold start emissions are reported using both, the traditional bag method as well as the regression model. At room temperature a clear reduction of 94%, 81% and 85% was found for the methane, benzene and alkyl benzene cold start emissions from EURO-0 to EURO-3 technology, respectively.

Observations and simulations of snowpack cold content and its relationship to snowmelt timing and rate

NASA Astrophysics Data System (ADS)

Jennings, K. S.; Molotch, N. P.

2017-12-01

Mountain snowpacks serve as a vital water resource for more than 1 billion people across the globe. Two key properties of snowmelt—rate and timing—are controlled by the snowpack energy budget where incoming positive fluxes are balanced by a decrease in the energy deficit of the snowpack and a change in the phase of water from solid to liquid. In this context, the energy deficit, or cold content, regulates snowmelt as runoff does not commence until the deficit approaches zero. There is significant uncertainty surrounding cold content despite its relevance to snowmelt processes, likely due to the inherent difficulties in its observation. Our work has clarified the previously unresolved meteorological and energy balance controls on cold content development in seasonal snowpacks by leveraging two unique datasets from the Niwot Ridge LTER in the Rocky Mountains of Colorado. The first is a long-term snow pit record of snowpack properties from an alpine and subalpine site within the LTER. These data were augmented with a 23-year simulation of the snowpack at both sites using a quality controlled, serially complete, hourly forcing dataset. The observations and simulations both indicated that cold content primarily developed through new snowfall, while a negative energy budget provided a secondary pathway for cold content development, mainly through longwave emission and sublimation. Cold content gains from snowfall outnumbered energy balance gains by 438% in the alpine and 166% in the subalpine. Increased spring precipitation and later peak cold content significantly delayed snowmelt onset and daily melt rates were reduced by 32.2% in the alpine and 36.1% in the subalpine when an energy deficit needed to be satisfied. Furthermore, preliminary climate change simulations indicated warmer air temperatures reduced cold content accumulation, which increased the amount of snow lost to melt throughout the winter as incoming positive fluxes had to overcome smaller energy deficits. Overall, this work shows that meteorological and energy balance processes that increase cold content (e.g., snowfall, longwave emission, and sublimation) delay snowmelt onset and damp snowmelt rate, a relationship that will likely be impacted by climate warming with resultant effects on water resource availability.

Gravitational waves from dark first order phase transitions and dark photons

NASA Astrophysics Data System (ADS)

Addazi, Andrea; Marcianò, Antonino

2018-01-01

Cold Dark Matter particles may interact with ordinary particles through a dark photon, which acquires a mass thanks to a spontaneous symmetry breaking mechanism. We discuss a dark photon model in which the scalar singlet associated to the spontaneous symmetry breaking has an effective potential that induces a first order phase transition in the early Universe. Such a scenario provides a rich phenomenology for electron-positron colliders and gravitational waves interferometers, and may be tested in several different channels. The hidden first order phase transition implies the emission of gravitational waves signals, which may constrain the dark photon’s space of parameters. Compared limits from electron-positron colliders, astrophysics, cosmology and future gravitational waves interferometers such as eLISA, U-DECIGO and BBO are discussed. This highly motivates a cross-checking strategy of data arising from experiments dedicated to gravitational waves, meson factories, the International Linear Collider (ILC), the Circular Electron Positron Collider (CEPC) and other underground direct detection experiments of cold dark matter candidates. Supported by the Shanghai Municipality (KBH1512299) and Fudan University (JJH1512105)

The Variable Warm Absorber in Circinus X-1

NASA Astrophysics Data System (ADS)

Schulz, N. S.; Kallman, T. E.; Galloway, D. K.; Brandt, W. N.

2008-01-01

We observed Circinus X-1 twice during a newly reached low-flux phase near zero orbital phase using the High-Energy Transmission Grating Spectrometer (HETGS) onboard Chandra. In both observations the source did not show the P Cygni lines we observed during the high-flux phases of the source in 2000 and 2001. During the prezero phase the source did not exhibit significant variability but did exhibit an emission-line spectrum rich in H- and He-like lines from high-Z elements such as Si, S, Ar, and Ca. The light curve in the postdip observation showed quiescent and flaring episodes. Only in these flaring episodes was the source luminosity significantly higher than observed during the prezero phase. We analyzed all high-resolution X-ray spectra by fitting photoionization and absorption models from the most recent version of the XSTAR code. The prezero-phase spectrum could be fully modeled with a very hot photoionized plasma with an ionization parameter of log ξ = 3.0, down from log ξ = 4.0 in the high-flux state. The ionization balances we measure from the spectra during the postzero-phase episodes are significantly different. Both episodes feature absorbers with variable high columns, ionization parameters, and luminosity. While cold absorption remains at levels quite similar to that observed in previous years, the new observations show unprecedented levels of variable warm absorption. The line emissivities also indicate that the observed low source luminosity is inconsistent with a static hot accretion disk corona (ADC), an effect that seems common to other near-edge-on ADC sources as well. We conclude that unless there exists some means of coronal heating other than X-rays, the true source luminosity is likely much higher, and we observe obscuration in analogy to the extragalactic Seyfert 2 sources. We discuss possible consequences and relate cold, lukewarm, warm, and hot absorbers to dynamic accretion scenarios.

Heat to electricity conversion by cold carrier emissive energy harvesters

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

Strandberg, Rune

2015-12-07

This paper suggests a method to convert heat to electricity by the use of devices called cold carrier emissive energy harvesters (cold carrier EEHs). The working principle of such converters is explained and theoretical power densities and efficiencies are calculated for ideal devices. Cold carrier EEHs are based on the same device structure as hot carrier solar cells, but works in an opposite way. Whereas a hot carrier solar cell receives net radiation from the sun and converts some of this radiative heat flow into electricity, a cold carrier EEH sustains a net outflux of radiation to the surroundings whilemore » converting some of the energy supplied to it into electricity. It is shown that the most basic type of cold carrier EEHs have the same theoretical efficiency as the ideal emissive energy harvesters described earlier by Byrnes et al. In the present work, it is also shown that if the emission from the cold carrier EEH originates from electron transitions across an energy gap where a difference in the chemical potential of the electrons above and below the energy gap is sustained, power densities slightly higher than those given by Byrnes et al. can be achieved.« less

Effects of Gasoline Direct Injection Engine Operating Parameters on Particle Number Emissions

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

He, X.; Ratcliff, M. A.; Zigler, B. T.

2012-04-19

A single-cylinder, wall-guided, spark ignition direct injection engine was used to study the impact of engine operating parameters on engine-out particle number (PN) emissions. Experiments were conducted with certification gasoline and a splash blend of 20% fuel grade ethanol in gasoline (E20), at four steady-state engine operating conditions. Independent engine control parameter sweeps were conducted including start of injection, injection pressure, spark timing, exhaust cam phasing, intake cam phasing, and air-fuel ratio. The results show that fuel injection timing is the dominant factor impacting PN emissions from this wall-guided gasoline direct injection engine. The major factor causing high PN emissionsmore » is fuel liquid impingement on the piston bowl. By avoiding fuel impingement, more than an order of magnitude reduction in PN emission was observed. Increasing fuel injection pressure reduces PN emissions because of smaller fuel droplet size and faster fuel-air mixing. PN emissions are insensitive to cam phasing and spark timing, especially at high engine load. Cold engine conditions produce higher PN emissions than hot engine conditions due to slower fuel vaporization and thus less fuel-air homogeneity during the combustion process. E20 produces lower PN emissions at low and medium loads if fuel liquid impingement on piston bowl is avoided. At high load or if there is fuel liquid impingement on piston bowl and/or cylinder wall, E20 tends to produce higher PN emissions. This is probably a function of the higher heat of vaporization of ethanol, which slows the vaporization of other fuel components from surfaces and may create local fuel-rich combustion or even pool-fires.« less

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...

Low-noise cold-field emission current obtained between two opposed carbon cone nanotips during in situ transmission electron microscope biasing

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

Knoop, L. de; Gatel, C.; Houdellier, F.

2015-06-29

A dedicated transmission electron microscope sample holder has been used to study in situ the cold-field emission process of carbon cone nanotips (CCnTs). We show that when using a CCnT instead of a Au plate-anode, the standard deviation of the emission current noise can be decreased from the 10 nA range to the 1 nA range under vacuum conditions of 10{sup −5 }Pa. This shows the strong influence of the anode on the cold-field emission current noise.

Application of modern online instrumentation for chemical analysis of gas and particulate phases of exhaust at the European Commission heavy-duty vehicle emission laboratory.

PubMed

Adam, T W; Chirico, R; Clairotte, M; Elsasser, M; Manfredi, U; Martini, G; Sklorz, M; Streibel, T; Heringa, M F; Decarlo, P F; Baltensperger, U; De Santi, G; Krasenbrink, A; Zimmermann, R; Prevot, A S H; Astorga, C

2011-01-01

The European Commission recently established a novel test facility for heavy-duty vehicles to enhance more sustainable transport. The facility enables the study of energy efficiency of various fuels/scenarios as well as the chemical composition of evolved exhaust emissions. Sophisticated instrumentation for real-time analysis of the gas and particulate phases of exhaust has been implemented. Thereby, gas-phase characterization was carried out by a Fourier transform infrared spectrometer (FT-IR; carbonyls, nitrogen-containing species, small hydrocarbons) and a resonance-enhanced multiphoton ionization time-of-flight mass spectrometer (REMPI-TOFMS; monocyclic and polycyclic aromatic hydrocarbons). For analysis of the particulate phase, a high-resolution time-of-flight aerosol mass spectrometer (HR-TOF-AMS; organic matter, chloride, nitrate), a condensation particle counter (CPC; particle number), and a multiangle absorption photometer (MAAP; black carbon) were applied. In this paper, the first application of the new facility in combination with the described instruments is presented, whereby a medium-size truck was investigated by applying different driving cycles. The goal was simultaneous chemical characterization of a great variety of gaseous compounds and particulate matter in exhaust on a real-time basis. The time-resolved data allowed new approaches to view the results; for example, emission factors were normalized to time-resolved consumption of fuel and were related to emission factors evolved during high speeds. Compounds could be identified that followed the fuel consumption, others showed very different behavior. In particular, engine cold start, engine ignition (unburned fuel), and high-speed events resulted in unique emission patterns.

A field-emission based vacuum device for the generation of THz waves

NASA Astrophysics Data System (ADS)

Lin, Ming-Chieh

2005-03-01

Terahertz waves have been used to characterize the electronic, vibrational and compositional properties of solid, liquid and gas phase materials during the past decade. More and more applications in imaging science and technology call for the well development of THz wave sources. Amplification and generation of a high frequency electromagnetic wave are a common interest of field emission based devices. In the present work, we propose a vacuum electronic device based on field emission mechanism for the generation of THz waves. To verify our thinking and designs, the cold tests and the hot tests have been studied via the simulation tools, SUPERFISH and MAGIC. In the hot tests, two types of electron emission mechanisms are considered. One is the field emission and the other is the explosive emission. The preliminary design of the device is carried out and tested by the numerical simulations. The simulation results show that an electronic efficiency up to 4% can be achieved without employing any magnetic circuits.

Integrated low emissions cleanup system for direct coal-fueled turbines

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

Lippert, T.E.; Newby, R.A.; Alvin, M.A.

1992-01-01

The Westinghouse Electric Corporation, Science Technology Center (W-STC) is developing an Integrated Low Emissions Cleanup (ILEC) concept for high-temperature gas cleaning to meet environmental standards, as well as to economical gas turbine life. The ILEC concept simultaneously controls sulfur, particulate, and alkali contaminants in high-pressure fuel gases or combustion gases at temperatures up to 1850[degrees]F for advanced power generation systems (PFBC, APFBC, IGCC, DCF7). The objective of this program is to demonstrate, at a bench scale, the conceptual, technical feasibility of the REC concept. The ELEC development program has a 3 phase structure: Phase 1 - laboratory-scale testing; phase 2more » - bench-scale equipment; design and fabrication; and phase 3 - bench-scale testing. Phase 1 laboratory testing has been completed. In Phase 1, entrained sulfur and alkali sorbent kinetics were measured and evaluated, and commercial-scale performance was projected. Related cold flow model testing has shown that gas-particle contacting within the ceramic barrier filter vessel will provide a good reactor environment. The Phase 1 test results and the commercial evaluation conducted in the Phase 1 program support the bench-scale facility testing to be performed in Phase 3. Phase 2 is nearing completion with the design and assembly of a modified, bench-scale test facility to demonstrate the technical feasibility of the ILEC features. This feasibility testing will be conducted in Phase 3.« less

Statistics of “Cold” Early Impulsive Solar Flares in X-Ray and Microwave Domains

NASA Astrophysics Data System (ADS)

Lysenko, Alexandra L.; Altyntsev, Alexander T.; Meshalkina, Natalia S.; Zhdanov, Dmitriy; Fleishman, Gregory D.

2018-04-01

Solar flares often happen after a preflare/preheating phase, which is almost or entirely thermal. In contrast, there are the so-called early impulsive flares that do not show a (significant) preflare heating, but instead often show the Neupert effect—a relationship where the impulsive phase is followed by a gradual, cumulative-like, thermal response. This has been interpreted as a dominance of nonthermal energy release at the impulsive phase, even though a similar phenomenology is expected if the thermal and nonthermal energies are released in comparable amounts at the impulsive phase. Nevertheless, some flares do show a good quantitative correspondence between the nonthermal electron energy input and plasma heating; in such cases, the thermal response was weak, which results in them being called “cold” flares. We undertook a systematic search for such events among early impulsive flares registered by the Konus-Wind instrument in the triggered mode from 11/1994 to 4/2017, and selected 27 cold flares based on relationships between hard X-ray (HXR) (Konus-Wind) and soft X-ray (Geostationary Operational Environmental Satellite) emission. For these events, we put together all available microwave data from different instruments. We obtained temporal and spectral parameters of HXR and microwave emissions of the events and examined correlations between them. We found that, compared to a “mean” flare, the cold flares: (i) are weaker, shorter, and harder in the X-ray domain; (ii) are harder and shorter, but not weaker in the microwaves; (iii) have a significantly higher spectral peak frequencies in the microwaves. We discuss the possible physical reasons for these distinctions and implication of the finding.

ALMA OBSERVATIONS OF THE COLDEST PLACE IN THE UNIVERSE: THE BOOMERANG NEBULA

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

Sahai, R.; Vlemmings, W. H. T.; Huggins, P. J.

The Boomerang Nebula is the coldest known object in the universe, and an extreme member of the class of pre-planetary nebulae, objects which represent a short-lived transitional phase between the asymptotic giant branch and planetary nebula evolutionary stages. Previous single-dish CO (J = 1-0) observations (with a 45'' beam) showed that the high-speed outflow in this object has cooled to a temperature significantly below the temperature of the cosmic background radiation. Here we report the first observations of the Boomerang Nebula with ALMA in the CO J = 2-1 and J = 1-0 lines to resolve the structure of thismore » ultra-cold nebula. We find a central hourglass-shaped nebula surrounded by a patchy, but roughly round, cold high-velocity outflow. We compare the ALMA data with visible-light images obtained with the Hubble Space Telescope and confirm that the limb-brightened bipolar lobes seen in these data represent hollow cavities with dense walls of molecular gas and dust producing both the molecular-emission-line and scattered-light structures seen at millimeter and visible wavelengths. The large diffuse biconical shape of the nebula seen in the visible wavelength range is likely due to preferential illumination of the cold, high-velocity outflow. We find a compact source of millimeter-wave continuum in the nebular waist—these data, together with sensitive upper limits on the radio continuum using observations with ATCA, indicate the presence of a substantial mass of very large (millimeter-sized) grains in the waist of the nebula. Another unanticipated result is the detection of CO emission regions beyond the ultra-cold region which indicate the re-warming of the cold gas, most likely due to photoelectric grain heating.« less

ALMA Observations of the Coldest Place in the Universe: The Boomerang Nebula

NASA Astrophysics Data System (ADS)

Sahai, R.; Vlemmings, W. H. T.; Huggins, P. J.; Nyman, L.-Å.; Gonidakis, I.

2013-11-01

The Boomerang Nebula is the coldest known object in the universe, and an extreme member of the class of pre-planetary nebulae, objects which represent a short-lived transitional phase between the asymptotic giant branch and planetary nebula evolutionary stages. Previous single-dish CO (J = 1-0) observations (with a 45'' beam) showed that the high-speed outflow in this object has cooled to a temperature significantly below the temperature of the cosmic background radiation. Here we report the first observations of the Boomerang Nebula with ALMA in the CO J = 2-1 and J = 1-0 lines to resolve the structure of this ultra-cold nebula. We find a central hourglass-shaped nebula surrounded by a patchy, but roughly round, cold high-velocity outflow. We compare the ALMA data with visible-light images obtained with the Hubble Space Telescope and confirm that the limb-brightened bipolar lobes seen in these data represent hollow cavities with dense walls of molecular gas and dust producing both the molecular-emission-line and scattered-light structures seen at millimeter and visible wavelengths. The large diffuse biconical shape of the nebula seen in the visible wavelength range is likely due to preferential illumination of the cold, high-velocity outflow. We find a compact source of millimeter-wave continuum in the nebular waist—these data, together with sensitive upper limits on the radio continuum using observations with ATCA, indicate the presence of a substantial mass of very large (millimeter-sized) grains in the waist of the nebula. Another unanticipated result is the detection of CO emission regions beyond the ultra-cold region which indicate the re-warming of the cold gas, most likely due to photoelectric grain heating.

Lurking systematics in predicting galaxy cold gas masses using dust luminosities and star formation rates

NASA Astrophysics Data System (ADS)

Janowiecki, Steven; Cortese, Luca; Catinella, Barbara; Goodwin, Adelle J.

2018-05-01

We use galaxies from the Herschel Reference Survey to evaluate commonly used indirect predictors of cold gas masses. We calibrate predictions for cold neutral atomic and molecular gas using infrared dust emission and gas depletion time methods that are self-consistent and have ˜20 per cent accuracy (with the highest accuracy in the prediction of total cold gas mass). However, modest systematic residual dependences are found in all calibrations that depend on the partition between molecular and atomic gas, and can over/underpredict gas masses by up to 0.3 dex. As expected, dust-based estimates are best at predicting the total gas mass while depletion time-based estimates are only able to predict the (star-forming) molecular gas mass. Additionally, we advise caution when applying these predictions to high-z galaxies, as significant (0.5 dex or more) errors can arise when incorrect assumptions are made about the dominant gas phase. Any scaling relations derived using predicted gas masses may be more closely related to the calibrations used than to the actual galaxies observed.

Integrated low emissions cleanup system for direct coal-fueled turbines

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

Lippert, T.E.; Newby, R.A.; Alvin, M.A.

1992-12-31

The Westinghouse Electric Corporation, Science & Technology Center (W-STC) is developing an Integrated Low Emissions Cleanup (ILEC) concept for high-temperature gas cleaning to meet environmental standards, as well as to economical gas turbine life. The ILEC concept simultaneously controls sulfur, particulate, and alkali contaminants in high-pressure fuel gases or combustion gases at temperatures up to 1850{degrees}F for advanced power generation systems (PFBC, APFBC, IGCC, DCF7). The objective of this program is to demonstrate, at a bench scale, the conceptual, technical feasibility of the REC concept. The ELEC development program has a 3 phase structure: Phase 1 - laboratory-scale testing; phasemore » 2 - bench-scale equipment; design and fabrication; and phase 3 - bench-scale testing. Phase 1 laboratory testing has been completed. In Phase 1, entrained sulfur and alkali sorbent kinetics were measured and evaluated, and commercial-scale performance was projected. Related cold flow model testing has shown that gas-particle contacting within the ceramic barrier filter vessel will provide a good reactor environment. The Phase 1 test results and the commercial evaluation conducted in the Phase 1 program support the bench-scale facility testing to be performed in Phase 3. Phase 2 is nearing completion with the design and assembly of a modified, bench-scale test facility to demonstrate the technical feasibility of the ILEC features. This feasibility testing will be conducted in Phase 3.« less

Real-time black carbon emission factors of light-duty vehicles tested on a chassis dynamometer

NASA Astrophysics Data System (ADS)

Forestieri, S. D.; Cappa, C. D.; Kuwayama, T.; Collier, S.; Zhang, Q.; Kleeman, M. J.

2012-12-01

Eight light-duty gasoline vehicles were tested on a Chassis dynamometer using the California Unified Driving Cycle (UDC) at the Haagen-Smit vehicle test facility at the California Air Resources Board (CARB) in El Monte, CA during September 2011. In addition, one light-duty gasoline vehicle, one ultra low-emission vehicle, one diesel passenger vehicle, and one gasoline direct injection vehicle were tested on a constant velocity driving cycle. Vehicle exhaust was diluted through CARB's CVS tunnel and a secondary dilution system in order to examine particulate matter (PM) emissions at atmospherically relevant concentrations (5-30 μg-m3). A variety of real-time instrumentation was used to characterize how the major PM components vary during a typical driving cycle, which includes a cold start phase followed by a hot stabilized running phase. Aerosol absorption coefficients were obtained at 532 nm and 405 nm with a time resolution of 2 seconds from a photo-acoustic spectrometer. These absorption coefficients were then converted to black carbon (BC) concentrations via a mass absorption coefficient. Non-refractory organic and inorganic PM and CO2 concentrations were quantified with a time resolution of 10 seconds using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS). Real-time BC and CO2 concentrations allowed for the determination of BC emission factors (EFs), providing insights into the variability of BC EFs during different phases of a typical driving cycle and aiding in the modeling BC emissions.

The role of deep convection and nocturnal low-level jets for dust emission in summertime West Africa: Estimates from convection-permitting simulations

PubMed Central

Heinold, B; Knippertz, P; Marsham, JH; Fiedler, S; Dixon, NS; Schepanski, K; Laurent, B; Tegen, I

2013-01-01

[1] Convective cold pools and the breakdown of nocturnal low-level jets (NLLJs) are key meteorological drivers of dust emission over summertime West Africa, the world’s largest dust source. This study is the first to quantify their relative contributions and physical interrelations using objective detection algorithms and an off-line dust emission model applied to convection-permitting simulations from the Met Office Unified Model. The study period covers 25 July to 02 September 2006. All estimates may therefore vary on an interannual basis. The main conclusions are as follows: (a) approximately 40% of the dust emissions are from NLLJs, 40% from cold pools, and 20% from unidentified processes (dry convection, land-sea and mountain circulations); (b) more than half of the cold-pool emissions are linked to a newly identified mechanism where aged cold pools form a jet above the nocturnal stable layer; (c) 50% of the dust emissions occur from 1500 to 0200 LT with a minimum around sunrise and after midday, and 60% of the morning-to-noon emissions occur under clear skies, but only 10% of the afternoon-to-nighttime emissions, suggesting large biases in satellite retrievals; (d) considering precipitation and soil moisture effects, cold-pool emissions are reduced by 15%; and (e) models with parameterized convection show substantially less cold-pool emissions but have larger NLLJ contributions. The results are much more sensitive to whether convection is parameterized or explicit than to the choice of the land-surface characterization, which generally is a large source of uncertainty. This study demonstrates the need of realistically representing moist convection and stable nighttime conditions for dust modeling. Citation: Heinold, B., P. Knippertz, J. H. Marsham, S. Fiedler, N. S. Dixon, K. Schepanski, B. Laurent, and I. Tegen (2013), The role of deep convection and nocturnal low-level jets for dust emission in summertime West Africa: Estimates from convection-permitting simulations, J. Geophys. Res. Atmos., 118, 4385–4400, doi:10.1002/jgrd.50402. PMID:25893153

Laser spectroscopy of a halocarbocation in the gas phase: CH2I+.

PubMed

Tao, Chong; Mukarakate, Calvin; Reid, Scott A

2006-07-26

We report the first gas-phase observation of the electronic spectrum of a simple halocarbocation, CH2I+. The ion was generated rotationally cold (Trot approximately 20 K) using pulsed discharge methods and was detected via laser spectroscopy. The identity of the spectral carrier was confirmed by modeling the rotational contour observed in the excitation spectra and by comparison of ground state vibrational frequencies determined by single vibronic level emission spectroscopy with Density Functional Theory (DFT) predictions. The transition was assigned as 3A1 <-- X1A1. This initial detection of the electronic spectrum of a halocarbocation in the gas phase should open new avenues for study of the structure and reactivity of these important ions.

40 CFR 63.7690 - What emissions limitations must I meet?

Code of Federal Regulations, 2010 CFR

2010-07-01

... exceed a flow-weighted average of 20 ppmv. (11) For each triethylamine (TEA) cold box mold or core making... section: (i) You must not discharge emissions of TEA through a conveyance to the atmosphere that exceed 1... reduce emissions of TEA from each TEA cold box mold or core making line by at least 99 percent, as...

ORNL diagnostic and modeling development for LAPD ICRF experiments

NASA Astrophysics Data System (ADS)

Isler, R. C.; Caughman, J. B. O.; Lau, C.; Martin, E. H.; Perkins, R. J.; Compernolle, B. Van; Vincena, S.; Tripathi, S. K. P.; Gekelman, W.

2017-10-01

PPPL, UCLA, and ORNL scientists have recently collaborated on a three week ICRF campaign at the upgraded LAPD device to study near field-plasma interactions associated with a single strap antenna driven at 2.38 MHz with 100 kW of RF power. This poster highlights ORNL involvement through implementation of the following diagnostics: an optical emission probe to measure neutral density, a retarding field energy analyzer to measure fast ions, phase locked imaging to measure line integrated RF-driven optical emission fluctuations, and an RF compensated triple Langmuir probe to measure density and temperature. To interpret the results of the experimental campaign a 3D cold plasma finite element model with realistic antenna and vacuum vessel geometry was developed in COMSOL. A summary of these results will be discussed. Highlights include a proof of principle localized and spatially resolved measurement of the neutral density, a strong increase in RF-driven optical emission fluctuations directly in front of the RF antenna strap, a shift in fast ion energies near the plasma edge, and qualitative agreement between the COMSOL cold plasma model with the various diagnostics. Funded by the DOE OFES (DE-AC05-00OR22725, DE-AC02-09CH11466, and DE-FC02-07ER54918) and the Univ. of California (12-LR-237124).

Hundred Thousand Degree Gas in the Virgo Cluster of Galaxies

NASA Astrophysics Data System (ADS)

Sparks, W. B.; Pringle, J. E.; Carswell, R. F.; Donahue, M.; Martin, R.; Voit, M.; Cracraft, M.; Manset, N.; Hough, J. H.

2012-05-01

The physical relationship between low-excitation gas filaments at ~104 K, seen in optical line emission, and diffuse X-ray emitting coronal gas at ~107 K in the centers of many galaxy clusters is not understood. It is unclear whether the ~104 K filaments have cooled and condensed from the ambient hot (~107 K) medium or have some other origin such as the infall of cold gas in a merger, or the disturbance of an internal cool reservoir of gas by nuclear activity. Observations of gas at intermediate temperatures (~105-106 K) can potentially reveal whether the central massive galaxies are gaining cool gas through condensation or losing it through conductive evaporation and hence identify plausible scenarios for transport processes in galaxy cluster gas. Here we present spectroscopic detection of ~105 K gas spatially associated with the Hα filaments in a central cluster galaxy, M87, in the Virgo Cluster. The measured emission-line fluxes from triply ionized carbon (C IV 1549 Å) and singly ionized helium (He II 1640 Å) are consistent with a model in which thermal conduction determines the interaction between hot and cold phases.

Imaging strategies for the study of gas turbine spark ignition

NASA Astrophysics Data System (ADS)

Gord, James R.; Tyler, Charles; Grinstead, Keith D., Jr.; Fiechtner, Gregory J.; Cochran, Michael J.; Frus, John R.

1999-10-01

Spark-ignition systems play a critical role in the performance of essentially all gas turbine engines. These devices are responsible for initiating the combustion process that sustains engine operation. Demanding applications such as cold start and high-altitude relight require continued enhancement of ignition systems. To characterize advanced ignition systems, we have developed a number of laser-based diagnostic techniques configured for ultrafast imaging of spark parameters including emission, density, temperature, and species concentration. These diagnostics have been designed to exploit an ultrafast- framing charge-coupled-device (CCD) camera and high- repetition-rate laser sources including mode-locked Ti:sapphire oscillators and regenerative amplifiers. Spontaneous-emission and laser-shlieren measurements have been accomplished with this instrumentation and the result applied to the study of a novel Unison Industries spark igniter that shows great promise for improved cold-start and high-altitude-relight capability as compared to that of igniters currently in use throughout military and commercial fleets. Phase-locked and ultrafast real-time imaging strategies are explored, and details of the imaging instrumentation, particularly the CCD camera and laser sources, are discussed.

Impacts of ethanol fuel level on emissions of regulated and unregulated pollutants from a fleet of gasoline light-duty vehicles

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

Karavalakis, Georgios; Durbin, Thomas; Shrivastava, ManishKumar B.

The study investigated the impact of ethanol blends on criteria emissions (THC, NMHC, CO, NOx), greenhouse gas (CO2), and a suite of unregulated pollutants in a fleet of gasoline-powered light-duty vehicles. The vehicles ranged in model year from 1984 to 2007 and included one Flexible Fuel Vehicle (FFV). Emission and fuel consumption measurements were performed in duplicate or triplicate over the Federal Test Procedure (FTP) driving cycle using a chassis dynamometer for four fuels in each of seven vehicles. The test fuels included a CARB phase 2 certification fuel with 11% MTBE content, a CARB phase 3 certification fuel withmore » a 5.7% ethanol content, and E10, E20, E50, and E85 fuels. In most cases, THC and NMHC emissions were lower with the ethanol blends, while the use of E85 resulted in increases of THC and NMHC for the FFV. CO emissions were lower with ethanol blends for all vehicles and significantly decreased for earlier model vehicles. Results for NOx emissions were mixed, with some older vehicles showing increases with increasing ethanol level, while other vehicles showed either no impact or a slight, but not statistically significant, decrease. CO2 emissions did not show any significant trends. Fuel economy showed decreasing trends with increasing ethanol content in later model vehicles. There was also a consistent trend of increasing acetaldehyde emissions with increasing ethanol level, but other carbonyls did not show strong trends. The use of E85 resulted in significantly higher formaldehyde and acetaldehyde emissions than the specification fuels or other ethanol blends. BTEX and 1,3-butadiene emissions were lower with ethanol blends compared to the CARB 2 fuel, and were almost undetectable from the E85 fuel. The largest contribution to total carbonyls and other toxics was during the cold-start phase of FTP.« less

Strain Evolution in Cold-Warm Forged Steel Components Studied by Means of EBSD Technique

PubMed Central

Bonollo, Franco; Bassan, Fabio; Berto, Filippo

2017-01-01

Electron BackScatter Diffraction (EBSD) in conjunction with Field-Emission Environmental Scanning Electron Microscopy (FEG-ESEM) has been used to evaluate the microstructural and local plastic strain evolution in different alloys (AISI 1005, AISI 304L and Duplex 2205) deformed by a single-stage cold and warm forging process. The present work is aimed to describe the different behavior of the austenite and ferrite during plastic deformation as a function of different forging temperatures. Several topological EBSD maps have been measured on the deformed and undeformed states. Then, image quality factor, distributions of the grain size and misorientation have been analyzed in detail. In the austenitic stainless steel, the γ-phase has been found to harden more easily, then α-phase and γ-phase in AISI 1005 and in duplex stainless steel, sequentially. Compared to the high fraction of continuous dynamic recrystallized austenitic zones observed in stainless steels samples forged at low temperatures, the austenitic microstructure of samples forged at higher temperatures, 600–700 °C, has been found to be mainly characterized by large and elongated grains with some colonies of fine nearly-equiaxed grains attributed to discontinuous dynamic recrystallization. PMID:29258249

Characterization of Low Pressure Cold Plasma in the Cleaning of Contaminated Surfaces

NASA Technical Reports Server (NTRS)

Lanz, Devin Garrett; Hintze, Paul E.

2016-01-01

The characterization of low pressure cold plasma is a broad topic which would benefit many different applications involving such plasma. The characterization described in this paper focuses on cold plasma used as a medium in cleaning and disinfection applications. Optical Emission Spectroscopy (OES) and Mass Spectrometry (MS) are the two analytical methods used in this paper to characterize the plasma. OES analyzes molecules in the plasma phase by displaying the light emitted by the plasma molecules on a graph of wavelength vs. intensity. OES was most useful in identifying species which may interact with other molecules in the plasma, such as atomic oxygen or hydroxide radicals. Extracting useful data from the MS is done by filtering out the peaks generated by expected molecules and looking for peaks caused by foreign ones leaving the plasma chamber. This paper describes the efforts at setting up and testing these methods in order to accurately and effectively characterize the plasma.

The effects of neat biodiesel and biodiesel and HVO blends in diesel fuel on exhaust emissions from a light duty vehicle with a diesel engine.

PubMed

Prokopowicz, Adam; Zaciera, Marzena; Sobczak, Andrzej; Bielaczyc, Piotr; Woodburn, Joseph

2015-06-16

The influence of fatty acid methyl esters (FAME) and hydrotreated vegetable oil (HVO) diesel blends on the exhaust emissions from a passenger car was examined. The impact of FAME for the cold urban phase (UDC) was increased CO and HC emissions, probably due to blend physical properties promoting incomplete combustion. The HVO blend caused the lowest CO and HC emissions for the UDC. NOx emissions did not change significantly with the fuel used, however the UDC was characterized by lower NOx emission for FAME blends. Particle emissions were highest with standard diesel. Emissions of carbonyl compounds increased as fuel biodiesel content increased, especially during the UDC. HVO in diesel fuel decreased carbonyl emissions. Formaldehyde and acetaldehyde were the most abundant carbonyl compounds in the exhaust gas. Total particle-bound PAH emissions were variable, the emission of heavier PAHs increased with blend biodiesel content. The HVO blend increased emission of lighter PAHs. Nitro-PAHs were identified only during the UDC and not for all blends; the highest emissions were measured for pure diesel. The results showed that emission of nitro-PAHs may be decreased to a greater extent by using biodiesel than using a HVO blend.

A Herschel [C ii] Galactic plane survey. I. The global distribution of ISM gas components

NASA Astrophysics Data System (ADS)

Pineda, J. L.; Langer, W. D.; Velusamy, T.; Goldsmith, P. F.

2013-06-01

Context. The [C ii] 158 μm line is an important tool for understanding the life cycle of interstellar matter. Ionized carbon is present in a variety of phases of the interstellar medium (ISM), including the diffuse ionized medium, warm and cold atomic clouds, clouds in transition from atomic to molecular, and dense and warm photon dominated regions. Aims: Velocity-resolved observations of [C ii] are the most powerful technique available to disentangle the emission produced by these components. These observations can also be used to trace CO-dark H2 gas and determine the total mass of the ISM. Methods: The Galactic Observations of Terahertz C+ (GOT C+) project surveys the [C ii] 158 μm line over the entire Galactic disk with velocity-resolved observations using the Herschel/HIFI instrument. We present the first longitude-velocity maps of the [C ii] emission for Galactic latitudes b = 0°, ±0.5°, and ±1.0°. We combine these maps with those of H i, 12CO, and 13CO to separate the different phases of the ISM and study their properties and distribution in the Galactic plane. Results: [C ii] emission is mostly associated with spiral arms, mainly emerging from Galactocentric distances between 4 and 10 kpc. It traces the envelopes of evolved clouds as well as clouds that are in the transition between atomic and molecular. We estimate that most of the observed [C ii] emission is produced by dense photon dominated regions (~47%), with smaller contributions from CO-dark H2 gas (~28%), cold atomic gas (~21%), and ionized gas (~4%). Atomic gas inside the Solar radius is mostly in the form of cold neutral medium (CNM), while the warm neutral medium gas dominates the outer galaxy. The average fraction of CNM relative to total atomic gas is ~43%. We find that the warm and diffuse CO-dark H2 is distributed over a larger range of Galactocentric distances (4-11 kpc) than the cold and dense H2 gas traced by 12CO and 13CO (4-8 kpc). The fraction of CO-dark H2 to total H2 increases with Galactocentric distance, ranging from ~20% at 4 kpc to ~80% at 10 kpc. On average, CO-dark H2 accounts for ~30% of the molecular mass of the Milky Way. When the CO-dark H2 component is included, the radial distribution of the CO-to-H2 conversion factor is steeper than that when only molecular gas traced by CO is considered. Most of the observed [C ii] emission emerging from dense photon dominated regions is associated with modest far-ultraviolet fields in the range χ0 ≃ 1 - 30. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.Appendices are available in electronic form at http://www.aanda.org

Diurnal and seasonal variations of greenhouse gas emissions from a naturally ventilated dairy barn in a cold region

NASA Astrophysics Data System (ADS)

Huang, Dandan; Guo, Huiqing

2018-01-01

Carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) emissions were quantified for a naturally ventilated free-stall dairy barn in the Canadian Prairies climate through continuous measurements for a year from February 2015 to January 2016, with ventilation rate estimated by a CO2 mass balance method. The results were categorized into seasonal emission profiles with monthly data measured on a typical day, and diurnal profiles in cold (January), warm (July), and mild seasons (October) of all three gases. Seasonal CO2, CH4, and N2O concentrations greatly fluctuated within ranges of 593-2433 ppm, 15-152 ppm, and 0.32-0.40 ppm, respectively, with obviously higher concentrations in the cold season. Emission factors of the three gases were summarized: seasonal N2O emission varied between 0.5 and 10 μg s-1 AU-1 with lower emission in the cold season, while seasonal CO2 and CH4 emissions were within narrow ranges of 112-119 mg s-1 AU-1 and 2.5-3.5 mg s-1 AU-1. The result suggested a lower enteric CH4 emission for dairy cows than that estimated by Environment Canada (2014). Significant diurnal effects (P < 0.05) were observed for CH4 emissions in all seasons with higher emissions in the afternoons and evenings. The total greenhouse gas (GHG) emission, which was calculated by summing the three GHG in CO2 equivalent, was mainly contributed by CO2 and CH4 emissions and showed no significant seasonal variations (P > 0.05), but obvious diurnal variations in all seasons. In comparison with previous studies, it was found that the dairy barn in a cold region climate with smaller vent openings had relatively higher indoor CO2 and CH4 concentrations, but comparable CO2 and CH4 emissions to most previous studies. Besides, ventilation rate, temperature, and relative humidity all significantly affected the three gas concentrations with the outdoor temperature being the most relevant factor (P < 0.01); however, they showed less or no statistical relations to emissions.

­­Secondary organic aerosol formation from photo-oxidation of wood combustion emissions: Characterization of gas phase precursors and their link to SOA budget

NASA Astrophysics Data System (ADS)

Bhattu, D.; Stefenelli, G.; Zotter, P.; Zhou, J.; Nussbaumer, T.; Bertrand, A.; Marchand, N.; Termine-Roussel, B.; Baltensperger, U.; Slowik, J.; Prevot, A. S.; El-Haddad, I.; Dommen, J.

2016-12-01

Current legislation limits the emission of particulate matter, but does not regulate the precursors potentially forming secondary organic aerosol (SOA). Recent literature has shown that only 22 non-traditional SOA precursors from residential wood combustion explains 84-116% of the observed SOA mass whereas traditional precursors in the models account for only 3-27% of the SOA mass (Bruns et al., 2016). Investigation of gas phase emissions from wood combustion and their SOA formation potential have largely focused on single combustion devices with limited operating conditions. As, both primary emissions and SOA formation is a strong function of device type, load, fuel and operating conditions, we have performed a detailed chamber study investigating the gas-phase precursors from beech wood using three combustion devices namely a pellet boiler (combustion conditions: optimum, lack and excess of oxygen), an industrial wood chip grate boiler (30% and 100% power), and a log wood stove (varying fuel load and moisture content) using a potential aerosol mass reactor (PAM) with varying OH exposure. The short residence time in the reactor allowed a time resolved picture of SOA production potential and reduced wall losses. The main aim of this study is to characterize the primary and aged gaseous emissions and investigate their SOA formation potential depending on their mass yield, molecular structures, functional groups and OH reactivity in order to ascertain the contribution of residential wood burning in total carbonaceous OA budget. The physical and chemical effects of different OA aging conditions were monitored using an SMPS, an Aethalometer, an HR-ToF-AMS, as well as a PTR-ToF-MS and other gas monitors. In pellet boiler, significant SOA mass enhancement is observed in excess oxygen conditions compared to optimum and oxygen deprived conditions. Highest gas phase emissions from wood stove are observed at cold start (start of each burn cycle) and lowest in burn out phase (end of each burn cycle). Despite of the comparable total gas phase emissions, the compositional space of wood stove emissions is largely occupied by SOA precursors compared to pellet boiler. Finally we will determine effective SOA mass yield of the speciated and unspeciated precursors and assess the extent to which SOA mass closure can be achieved.

Hot gas, cold gas and sub-haloes in a Lyman α blob at redshift 2.38

NASA Astrophysics Data System (ADS)

Francis, Paul. J.; Dopita, Michael A.; Colbert, James W.; Palunas, Povilas; Scarlata, Claudia; Teplitz, Harry; Williger, Gerard M.; Woodgate, Bruce E.

2013-01-01

We present integral field spectroscopy of a Lyman α blob at redshift 2.38, with a spectral resolution three times better than previous published work. As with previous observations, the blob has a chaotic velocity structure, much of which breaks up into multiple components. Our spectroscopy shows, however, that some of these multiple components are extremely narrow: they have velocity widths of less than 100 km s- 1. Combining these new data with previous observations, we argue that this Lyman α blob resides in a dark matter halo of around 1013 M⊙. At the centre of this halo are two compact red massive galaxies. They are surrounded by hot gas, probably a superwind from merger-induced nuclear starbursts. This hot gas has shut down star formation in the non-nuclear region of these galaxies, leading to their red-and-dead colours. A filament or lump of infalling cold gas is colliding with the hot gas phase and being shocked to high temperatures, while still around 30 kpc from the red galaxies. The shock region is self-absorbed in Lyman α but produces C iv emission. Further out still, the cold gas in a number of sub-haloes is being lit up, most likely by a combination of tidally triggered star formation, bow shocks as they plough through the hot halo medium, resonant scattering of Lyman α from the filament collision and tidal stripping of gas which enhances the Lyman α escape fraction. The observed Lyman α emission from the blob is dominated by the sum of the emission from these sub-haloes. On statistical grounds, we argue that Lyman α blobs are not greatly elongated in shape and that most are not powered by ionization or scattering from a central active galactic nucleus or starburst.

A pulse tube cryocooler with a cold reservoir

NASA Astrophysics Data System (ADS)

Zhang, X. B.; Zhang, K. H.; Qiu, L. M.; Gan, Z. H.; Shen, X.; Xiang, S. J.

2013-02-01

Phase difference between pressure wave and mass flow is decisive to the cooling capacity of regenerative cryocoolers. Unlike the direct phase shifting using a piston or displacer in conventional Stirling or GM cryocoolers, the pulse tube cyocooler (PTC) indirectly adjusts the cold phase due to the absence of moving parts at the cold end. The present paper proposed and validated theoretically and experimentally a novel configuration of PTC, termed cold reservoir PTC, in which a reservoir together with an adjustable orifice is connected to the cold end of the pulse tube. The impedance from the additional orifice to the cold end helps to increase the mass flow in phase with the pressure wave at the cold end. Theoretical analyses with the linear model for the orifice and double-inlet PTCs indicate that the cooling performance can be improved by introducing the cold reservoir. The preliminary experiments with a home-made single-stage GM PTC further validated the results on the premise of minor opening of the cold-end orifice.

Optimization of Location-Routing Problem for Cold Chain Logistics Considering Carbon Footprint.

PubMed

Wang, Songyi; Tao, Fengming; Shi, Yuhe

2018-01-06

In order to solve the optimization problem of logistics distribution system for fresh food, this paper provides a low-carbon and environmental protection point of view, based on the characteristics of perishable products, and combines with the overall optimization idea of cold chain logistics distribution network, where the green and low-carbon location-routing problem (LRP) model in cold chain logistics is developed with the minimum total costs as the objective function, which includes carbon emission costs. A hybrid genetic algorithm with heuristic rules is designed to solve the model, and an example is used to verify the effectiveness of the algorithm. Furthermore, the simulation results obtained by a practical numerical example show the applicability of the model while provide green and environmentally friendly location-distribution schemes for the cold chain logistics enterprise. Finally, carbon tax policies are introduced to analyze the impact of carbon tax on the total costs and carbon emissions, which proves that carbon tax policy can effectively reduce carbon dioxide emissions in cold chain logistics network.

Astrochemical Properties of Planck Cold Clumps

NASA Astrophysics Data System (ADS)

Tatematsu, Ken'ichi; Liu, Tie; Ohashi, Satoshi; Sanhueza, Patricio; Nguyen Lu'o'ng, Quang; Hirota, Tomoya; Liu, Sheng-Yuan; Hirano, Naomi; Choi, Minho; Kang, Miju; Thompson, Mark A.; Fuller, Gary; Wu, Yuefang; Li, Di; Di Francesco, James; Kim, Kee-Tae; Wang, Ke; Ristorcelli, Isabelle; Juvela, Mika; Shinnaga, Hiroko; Cunningham, Maria; Saito, Masao; Lee, Jeong-Eun; Tóth, L. Viktor; He, Jinhua; Sakai, Takeshi; Kim, Jungha; JCMT Large Program "SCOPE" Collaboration; TRAO Key Science Program "TOP" Collaboration

2017-02-01

We observed 13 Planck cold clumps with the James Clerk Maxwell Telescope/SCUBA-2 and with the Nobeyama 45 m radio telescope. The N2H+ distribution obtained with the Nobeyama telescope is quite similar to SCUBA-2 dust distribution. The 82 GHz HC3N, 82 GHz CCS, and 94 GHz CCS emission are often distributed differently with respect to the N2H+ emission. The CCS emission, which is known to be abundant in starless molecular cloud cores, is often very clumpy in the observed targets. We made deep single-pointing observations in DNC, HN13C, N2D+, and cyclic-C3H2 toward nine clumps. The detection rate of N2D+ is 50%. Furthermore, we observed the NH3 emission toward 15 Planck cold clumps to estimate the kinetic temperature, and confirmed that most targets are cold (≲20 K). In two of the starless clumps we observed, the CCS emission is distributed as it surrounds the N2H+ core (chemically evolved gas), which resembles the case of L1544, a prestellar core showing collapse. In addition, we detected both DNC and N2D+. These two clumps are most likely on the verge of star formation. We introduce the chemical evolution factor (CEF) for starless cores to describe the chemical evolutionary stage, and analyze the observed Planck cold clumps.

Development of a high brightness ultrafast Transmission Electron Microscope based on a laser-driven cold field emission source.

PubMed

Houdellier, F; Caruso, G M; Weber, S; Kociak, M; Arbouet, A

2018-03-01

We report on the development of an ultrafast Transmission Electron Microscope based on a cold field emission source which can operate in either DC or ultrafast mode. Electron emission from a tungsten nanotip is triggered by femtosecond laser pulses which are tightly focused by optical components integrated inside a cold field emission source close to the cathode. The properties of the electron probe (brightness, angular current density, stability) are quantitatively determined. The measured brightness is the largest reported so far for UTEMs. Examples of imaging, diffraction and spectroscopy using ultrashort electron pulses are given. Finally, the potential of this instrument is illustrated by performing electron holography in the off-axis configuration using ultrashort electron pulses. Copyright © 2017 Elsevier B.V. All rights reserved.

40 CFR 600.113-12 - Fuel economy and carbon-related exhaust emission calculations for FTP, HFET, US06, SC03 and cold...

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Fuel economy and carbon-related exhaust emission calculations for FTP, HFET, US06, SC03 and cold temperature FTP tests. 600.113-12 Section 600.113-12 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) ENERGY POLICY FUEL ECONOMY AND CARBON-RELATED EXHAUST EMISSIONS OF...

Surfing Silicon Nanofacets for Cold Cathode Electron Emission Sites.

PubMed

Basu, Tanmoy; Kumar, Mohit; Saini, Mahesh; Ghatak, Jay; Satpati, Biswarup; Som, Tapobrata

2017-11-08

Point sources exhibit low threshold electron emission due to local field enhancement at the tip. In the case of silicon, however, the realization of tip emitters has been hampered by unwanted oxidation, limiting the number of emission sites and the overall current. In contrast to this, here, we report the fascinating low threshold (∼0.67 V μm -1 ) cold cathode electron emission from silicon nanofacets (Si-NFs). The ensembles of nanofacets fabricated at different time scales, under low energy ion impacts, yield tunable field emission with a Fowler-Nordheim tunneling field in the range of 0.67-4.75 V μm -1 . The local probe surface microscopy-based tunneling current mapping in conjunction with Kelvin probe force microscopy measurements revealed that the valleys and a part of the sidewalls of the nanofacets contribute more to the field emission process. The observed lowest turn-on field is attributed to the absence of native oxide on the sidewalls of the smallest facets as well as their lowest work function. In addition, first-principle density functional theory-based simulation revealed a crystal orientation-dependent work function of Si, which corroborates well with our experimental observations. The present study demonstrates a novel way to address the origin of the cold cathode electron emission sites from Si-NFs fabricated at room temperature. In principle, the present methodology can be extended to probe the cold cathode electron emission sites from any nanostructured material.

40 CFR 86.1809-12 - Prohibition of defeat devices.

Code of Federal Regulations, 2010 CFR

2010-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) General Compliance Provisions for Control of Air Pollution From New and In-Use Light-Duty Vehicles, Light... device. (c) For cold temperature CO and cold temperature NMHC emission control, the Administrator will...

40 CFR 86.1809-10 - Prohibition of defeat devices.

Code of Federal Regulations, 2010 CFR

2010-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) General Compliance Provisions for Control of Air Pollution From New and In-Use Light-Duty Vehicles, Light... device. (c) For cold temperature CO and cold temperature NMHC emission control, the Administrator will...

40 CFR 86.1809-12 - Prohibition of defeat devices.

Code of Federal Regulations, 2013 CFR

2013-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) General Compliance Provisions for Control of Air Pollution From New and In-Use Light-Duty Vehicles, Light... device. (c) For cold temperature CO and cold temperature NMHC emission control, the Administrator will...

40 CFR 86.1809-10 - Prohibition of defeat devices.

Code of Federal Regulations, 2011 CFR

2011-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) General Compliance Provisions for Control of Air Pollution From New and In-Use Light-Duty Vehicles, Light... device. (c) For cold temperature CO and cold temperature NMHC emission control, the Administrator will...

40 CFR 86.1809-10 - Prohibition of defeat devices.

Code of Federal Regulations, 2013 CFR

2013-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) General Compliance Provisions for Control of Air Pollution From New and In-Use Light-Duty Vehicles, Light... device. (c) For cold temperature CO and cold temperature NMHC emission control, the Administrator will...

40 CFR 86.1809-12 - Prohibition of defeat devices.

Code of Federal Regulations, 2011 CFR

2011-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) General Compliance Provisions for Control of Air Pollution From New and In-Use Light-Duty Vehicles, Light... device. (c) For cold temperature CO and cold temperature NMHC emission control, the Administrator will...

Steady-state, cavityless, multimode superradiance in a cold vapor

NASA Astrophysics Data System (ADS)

Greenberg, Joel A.; Gauthier, Daniel J.

2012-07-01

We demonstrate steady-state, mirrorless superradiance in a cold vapor pumped by weak optical fields. Beyond a critical pump intensity of 1 mW/cm2, the vapor spontaneously transforms into a spatially self-organized state: a density grating forms. Scattering of the pump beams off this grating generates a pair of new, intense optical fields that act back on the vapor to enhance the atomic organization. We map out experimentally the superradiant phase transition boundary and show that it is well described by our theoretical model. The resulting superradiant emission is nearly coherent, persists for several seconds, displays strong temporal correlations between the various modes, and has a coherence time of several hundred μs. This system therefore has applications in fundamental studies of many-body physics with long-range interactions as well as all-optical and quantum information processing.

Linear theory of plasma Čerenkov masers

NASA Astrophysics Data System (ADS)

Birau, M.

1996-11-01

A different theoretical model of Čerenkov instability in the linear amplification regime of plasma Čerenkov masers is developed. The model assumes a cold relativistic annular electron beam propagating through a column of cold dense plasma, the two bodies being immersed in an infinite magnetic guiding field inside a perfect cylindrical waveguide. In order to simplify the calculations, a radial rectangular distribution of plasma and beam density is assumed and only azimuthal symmetric modes are under investigation. The model's difference consists of taking into account the whole plasma and beam electromagnetic structures in the interpretation of the Čerenkov instability. This model leads to alternative results such as the possibility of emission at several frequencies. In addition, the electric field is calculated taking into account its radial phase dependence, so that a map of the field in the interaction region can be presented.

Dna Sequencing

DOEpatents

Hetrick, Robert Eugene; Hilbert, Harold Sean; Parsons, Michael Howard; Stockhausen, William Francis

1997-10-07

A fuel injection system used in the intake air passageway of an internal combustion engine has a strategy for reducing cold start hydrocarbon emissions. The fuel injector has an actuator which allows the fuel spray pattern to be varied from one which is widely dispersed and atomized to one which is only weakly dispersed. A strategy for varying the spray pattern during the engine warm-up period after cold start is disclosed. The strategy increases evaporation within the passageway so that cold start overfuelling and attendant hydrocarbon emissions are reduced.

Fabrication and testing of an enhanced ignition system to reduce cold-start emissions in an ethanol (E85) light-duty truck engine

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

Gardiner, D; Mallory, R; Todesco, M

This report describes an experimental investigation of the potential for an enhanced ignition system to lower the cold-start emissions of a light-duty vehicle engine using fuel ethanol (commonly referred to as E85). Plasma jet ignition and conventional inductive ignition were compared for a General Motors 4-cylinder, alcohol-compatible engine. Emission and combustion stability measurements were made over a range of air/fuel ratios and spark timing settings using a steady-state, cold-idle experimental technique in which the engine coolant was maintained at 25 C to simulate cold-running conditions. These tests were aimed at identifying the degree to which calibration strategies such as mixturemore » enleanment and retarded spark timing could lower engine-out hydrocarbon emissions and raise exhaust temperatures, as well as determining how such calibration changes would affect the combustion stability of the engine (as quantified by the coefficient of variation, or COV, of indicated mean effective pressure calculated from successive cylinder pressure measurements). 44 refs., 39 figs.« less

Astrochemical Properties of Planck Cold Clumps

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

Tatematsu, Ken’ichi; Sanhueza, Patricio; Nguyễn Lu’o’ng, Quang

We observed 13 Planck cold clumps with the James Clerk Maxwell Telescope/SCUBA-2 and with the Nobeyama 45 m radio telescope. The N{sub 2}H{sup +} distribution obtained with the Nobeyama telescope is quite similar to SCUBA-2 dust distribution. The 82 GHz HC{sub 3}N, 82 GHz CCS, and 94 GHz CCS emission are often distributed differently with respect to the N{sub 2}H{sup +} emission. The CCS emission, which is known to be abundant in starless molecular cloud cores, is often very clumpy in the observed targets. We made deep single-pointing observations in DNC, HN{sup 13}C, N{sub 2}D{sup +}, and cyclic-C{sub 3}H{sub 2}more » toward nine clumps. The detection rate of N{sub 2}D{sup +} is 50%. Furthermore, we observed the NH{sub 3} emission toward 15 Planck cold clumps to estimate the kinetic temperature, and confirmed that most targets are cold (≲20 K). In two of the starless clumps we observed, the CCS emission is distributed as it surrounds the N{sub 2}H{sup +} core (chemically evolved gas), which resembles the case of L1544, a prestellar core showing collapse. In addition, we detected both DNC and N{sub 2}D{sup +}. These two clumps are most likely on the verge of star formation. We introduce the chemical evolution factor (CEF) for starless cores to describe the chemical evolutionary stage, and analyze the observed Planck cold clumps.« less

Infrared Spectral Energy Distribution Decomposition of WISE-selected, Hyperluminous Hot Dust-obscured Galaxies

NASA Astrophysics Data System (ADS)

Fan, Lulu; Han, Yunkun; Nikutta, Robert; Drouart, Guillaume; Knudsen, Kirsten K.

2016-06-01

We utilize a Bayesian approach to fit the observed mid-IR-to-submillimeter/millimeter spectral energy distributions (SEDs) of 22 WISE-selected and submillimeter-detected, hyperluminous hot dust-obscured galaxies (Hot DOGs), with spectroscopic redshift ranging from 1.7 to 4.6. We compare the Bayesian evidence of a torus plusgraybody (Torus+GB) model with that of a torus-only (Torus) model and find that the Torus+GB model has higher Bayesian evidence for all 22 Hot DOGs than the torus-only model, which presents strong evidence in favor of the Torus+GB model. By adopting the Torus+GB model, we decompose the observed IR SEDs of Hot DOGs into torus and cold dust components. The main results are as follows. (1) Hot DOGs in our submillimeter-detected sample are hyperluminous ({L}{IR}≥slant {10}13{L}⊙ ), with torus emission dominating the IR energy output. However, cold dust emission is non-negligible, contributing on average ˜ 24% of total IR luminosity. (2) Compared to QSO and starburst SED templates, the median SED of Hot DOGs shows the highest luminosity ratio between mid-IR and submillimeter at rest frame, while it is very similar to that of QSOs at ˜ 10{--}50 μ {{m}}, suggesting that the heating sources of Hot DOGs should be buried AGNs. (3) Hot DOGs have high dust temperatures ({T}{dust}˜ 72 K) and high IR luminosity of cold dust. The {T}{dust}{--}{L}{IR} relation of Hot DOGs suggests that the increase in IR luminosity for Hot DOGs is mostly due to the increase of the dust temperature, rather than dust mass. Hot DOGs have lower dust masses than submillimeter galaxies (SMGs) and QSOs within a similar redshift range. Both high IR luminosity of cold dust and relatively low dust mass in Hot DOGs can be expected by their relatively high dust temperatures. (4) Hot DOGs have high dust-covering factors (CFs), which deviate from the previously proposed trend of the dust CF decreasing with increasing bolometric luminosity. Finally, we can reproduce the observed properties in Hot DOGs by employing a physical model of galaxy evolution. This result suggests that Hot DOGs may lie at or close to peaks of both star formation and black hole growth histories, and represent a transit phase during the evolutions of massive galaxies, transforming them from the dusty starburst-dominated phase to the optically bright QSO phase.

The influence of cold pack on labour pain relief and birth outcomes: a randomised controlled trial.

PubMed

Shirvani, Marjan Ahmad; Ganji, Zhila

2014-09-01

(1) To evaluate the influence of local cold on severity of labour pain and (2) to identify the effect of local cold on maternal and neonatal outcomes. Fear of labour pain results in an increase in pain and duration of labour, maternal discontent and demand for caesarean section. Regarding maternal and foetal complications of analgesic medications, the attention to application of nonpharmacological methods including cold therapy is increased. Randomised controlled trial. Sixty-four pregnant women, at initiation of active phase of labour, were allocated randomly to cold therapy and control groups (n = 64). Null parity, term pregnancy, presence of single foetus, cephalic presentation and completing informed consent were considered as inclusion criteria. Administration of analgesic and anaesthesia, foetal distress, skin lesions in regions of cold therapy and high-risk pregnancy provided exclusion criteria. Cold pack was applied over abdomen and back, for 10 minutes every 30 minutes during first phase of labour. Additionally, cold pack was placed over perineum, for 5 minutes every 15 minutes during second phase. Pain severity was assessed based on the visual analogue scale. The two groups were not significantly different considering demographic data, gestational age, foetal weight, rupture of membranes and primary severity of pain. Degree of pain was lower in cold therapy group during all parts of active phase and second stage. Duration of all phases was shorter in cold therapy group in all phases. Foetal heart rate, perineal laceration, type of birth, application of oxytocin and APGAR score were not significantly different between two groups. Labour pain is probably reduced based on gate theory using cold. Pain control by cold maybe improves labour progression without affecting mother and foetus adversely. Local cold therapy could be included in labour pain management. © 2013 John Wiley & Sons Ltd.

Development program on a Spindt cold-cathode electron gun

NASA Technical Reports Server (NTRS)

Spindt, C. A.

1982-01-01

A thin film field emission cathode (TFFEC) array and a cold cathode electron gun based on the emitter were developed. A microwave tube gun that uses the thin film field emission cathode as an electron source is produced. State-of-the-art cathodes were fabricated and tested. The tip-packing density of the arrays were increased thereby increasing the cathode's current density capability. The TFFEC is based on the well known field emission effect and was conceived to exploit the advantages of that phenomenon while minimizing the difficulties associated with conventional field emission structures, e.g. limited life and high voltage requirements. Field emission follows the Fowler-Nordheim equation.

Optimization of Location–Routing Problem for Cold Chain Logistics Considering Carbon Footprint

PubMed Central

Wang, Songyi; Tao, Fengming; Shi, Yuhe

2018-01-01

In order to solve the optimization problem of logistics distribution system for fresh food, this paper provides a low-carbon and environmental protection point of view, based on the characteristics of perishable products, and combines with the overall optimization idea of cold chain logistics distribution network, where the green and low-carbon location–routing problem (LRP) model in cold chain logistics is developed with the minimum total costs as the objective function, which includes carbon emission costs. A hybrid genetic algorithm with heuristic rules is designed to solve the model, and an example is used to verify the effectiveness of the algorithm. Furthermore, the simulation results obtained by a practical numerical example show the applicability of the model while provide green and environmentally friendly location-distribution schemes for the cold chain logistics enterprise. Finally, carbon tax policies are introduced to analyze the impact of carbon tax on the total costs and carbon emissions, which proves that carbon tax policy can effectively reduce carbon dioxide emissions in cold chain logistics network. PMID:29316639

Influence of driving cycles on unit emissions from passenger cars

NASA Astrophysics Data System (ADS)

Joumard, R.; André, M.; Vidon, R.; Tassel, P.; Pruvost, C.

Small samples of petrol engine or diesel cars, equipped with or without catalysts, were tested over 36 driving cycles divided into four categories - standard cycles and three sets of cycles more representative of real-world driving conditions. The tests addressed standard gaseous pollutants and fuel consumption and also less frequently measured pollutant such as CH 4. In the first part of this paper we examine cold emissions in order to assess the duration of the cold start impact and the representativity of the cold ECE15 cycle. Then unit emissions are compared over the four driving cycle families. As compared to representative cycles, the standardised cycles underestimate hot emissions by almost 50% for petrol engine cars and 30% for diesel vehicles. Conversely, the results obtained for the three representative cycle families are in relatively close agreement with each other - within approximately 10%. However, the cinematic properties of the three families differ. Finally, we demonstrate that weighting all emission data equally, not taking into account the weight of each cycle in overall traffic, introduces significant biases, particularly when plotting emission vs. average speed curves.

Cutaneous microvascular response during local cold exposure - the effect of female sex hormones and cold perception.

PubMed

Cankar, Ksenija; Music, Mark; Finderle, Zare

2016-11-01

It is generally known that differences exist between males and females with regard to sensitivity to cold. Similar differences even among females in different hormonal balance might influence microvascular response during cold provocation testing. The aim of the present study was to measure sex hormone levels, cold and cold pain perception thresholds and compare them to cutaneous laser-Doppler flux response during local cooling in both the follicular and luteal phases of the menstrual cycle. In the luteal phase a more pronounced decrease in laser-Doppler flux was observed compared to follicular phase during local cooling at 15°C (significant difference by Dunnett's test, p<0.05). In addition, statistically significant correlations between progesterone level and laser-Doppler flux response to local cooling were observed during the follicular (R=-0.552, p=0.0174) and during the luteal phases (R=0.520, p=0.0271). In contrast, the correlation between estradiol level and laser-Doppler flux response was observed only in the follicular phase (R=-0.506, p=0.0324). Our results show that individual sensitivity to cold influences cutaneous microvascular response to local cooling; that microvascular reactivity is more pronounced during the luteal phase of the menstrual cycle; and that reactivity correlates with hormone levels. The effect of specific sex hormone levels is related to the cold-provocation temperature. Copyright © 2016. Published by Elsevier Inc.

Pressure resistance of cold-shocked Escherichia coli O157:H7 in ground beef, beef gravy and peptone water.

PubMed

Baccus-Taylor, G S H; Falloon, O C; Henry, N

2015-06-01

(i) To study the effects of cold shock on Escherichia coli O157:H7 cells. (ii) To determine if cold-shocked E. coli O157:H7 cells at stationary and exponential phases are more pressure-resistant than their non-cold-shocked counterparts. (iii) To investigate the baro-protective role of growth media (0·1% peptone water, beef gravy and ground beef). Quantitative estimates of lethality and sublethal injury were made using the differential plating method. There were no significant differences (P > 0·05) in the number of cells killed; cold-shocked or non-cold-shocked. Cells grown in ground beef (stationary and exponential phases) experienced lowest death compared with peptone water and beef gravy. Cold-shock treatment increased the sublethal injury to cells cultured in peptone water (stationary and exponential phases) and ground beef (exponential phase), but decreased the sublethal injury to cells in beef gravy (stationary phase). Cold shock did not confer greater resistance to stationary or exponential phase cells pressurized in peptone water, beef gravy or ground beef. Ground beef had the greatest baro-protective effect. Real food systems should be used in establishing food safety parameters for high-pressure treatments; micro-organisms are less resistant in model food systems, the use of which may underestimate the organisms' resistance. © 2015 The Society for Applied Microbiology.

A multi-scale comparison of modeled and observed seasonal methane emissions in northern wetlands

DOE PAGES

Xu, Xiyan; Riley, William J.; Koven, Charles D.; ...

2016-09-13

Wetlands are the largest global natural methane (CH 4) source, and emissions between 50 and 70° N latitude contribute 10-30 % to this source. Predictive capability of land models for northern wetland CH 4 emissions is still low due to limited site measurements, strong spatial and temporal variability in emissions, and complex hydrological and biogeochemical dynamics. To explore this issue, we compare wetland CH 4 emission predictions from the Community Land Model 4.5 (CLM4.5-BGC) with site- to regional-scale observations. A comparison of the CH 4 fluxes with eddy flux data highlighted needed changes to the model's estimate of aerenchyma area,more » which we implemented and tested. The model modification substantially reduced biases in CH 4 emissions when compared with CarbonTracker CH 4 predictions. CLM4.5 CH 4 emission predictions agree well with growing season (May–September) CarbonTracker Alaskan regional-level CH 4 predictions and site-level observations. However, CLM4.5 underestimated CH 4 emissions in the cold season (October–April). The monthly atmospheric CH 4 mole fraction enhancements due to wetland emissions are also assessed using the Weather Research and Forecasting-Stochastic Time-Inverted Lagrangian Transport (WRF-STILT) model coupled with daily emissions from CLM4.5 and compared with aircraft CH 4 mole fraction measurements from the Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE) campaign. Both the tower and aircraft analyses confirm the underestimate of cold-season CH 4 emissions by CLM4.5. The greatest uncertainties in predicting the seasonal CH 4 cycle are from the wetland extent, cold-season CH 4 production and CH 4 transport processes. We recommend more cold-season experimental studies in high-latitude systems, which could improve the understanding and parameterization of ecosystem structure and function during this period. Predicted CH 4 emissions remain uncertain, but we show here that benchmarking against observations across spatial scales can inform model structural and parameter improvements.« less

A multi-scale comparison of modeled and observed seasonal methane emissions in northern wetlands

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

Xu, Xiyan; Riley, William J.; Koven, Charles D.

Wetlands are the largest global natural methane (CH 4) source, and emissions between 50 and 70° N latitude contribute 10-30 % to this source. Predictive capability of land models for northern wetland CH 4 emissions is still low due to limited site measurements, strong spatial and temporal variability in emissions, and complex hydrological and biogeochemical dynamics. To explore this issue, we compare wetland CH 4 emission predictions from the Community Land Model 4.5 (CLM4.5-BGC) with site- to regional-scale observations. A comparison of the CH 4 fluxes with eddy flux data highlighted needed changes to the model's estimate of aerenchyma area,more » which we implemented and tested. The model modification substantially reduced biases in CH 4 emissions when compared with CarbonTracker CH 4 predictions. CLM4.5 CH 4 emission predictions agree well with growing season (May–September) CarbonTracker Alaskan regional-level CH 4 predictions and site-level observations. However, CLM4.5 underestimated CH 4 emissions in the cold season (October–April). The monthly atmospheric CH 4 mole fraction enhancements due to wetland emissions are also assessed using the Weather Research and Forecasting-Stochastic Time-Inverted Lagrangian Transport (WRF-STILT) model coupled with daily emissions from CLM4.5 and compared with aircraft CH 4 mole fraction measurements from the Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE) campaign. Both the tower and aircraft analyses confirm the underestimate of cold-season CH 4 emissions by CLM4.5. The greatest uncertainties in predicting the seasonal CH 4 cycle are from the wetland extent, cold-season CH 4 production and CH 4 transport processes. We recommend more cold-season experimental studies in high-latitude systems, which could improve the understanding and parameterization of ecosystem structure and function during this period. Predicted CH 4 emissions remain uncertain, but we show here that benchmarking against observations across spatial scales can inform model structural and parameter improvements.« less

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

Bates, G.J.; Germano, S.

Tests were undertaken with a Renault Express 1.4 litre converted to natural gas operation. The effect of cold starts at cold temperatures and vehicle weight on tail pipe emissions were investigated with petrol and natural gas operation over the FTP75 and the 91/441/EEC drive cycles. The results show that the emissions with natural gas are unaffected by cold temperature, unlike petrol emissions which are several times higher at -15{degree}-C than at 25{degree}-C. A crude simulation, accounting for the actual temperature, shows that the conversion of a significant quantity of light duty vehicles to natural gas operation could reduce the emissionsmore » of CO and HC by more than 90% in Switzerland. 15 refs., 17 figs., 8 tabs.« less

40 CFR 1054.110 - What evaporative emission standards must my handheld equipment meet?

Code of Federal Regulations, 2014 CFR

2014-07-01

... must meet the permeation requirements for EPA Nonroad Fuel Lines or EPA Cold-Weather Fuel Lines as... that are not used in cold-weather equipment. For fuel lines used in cold-weather equipment, you may...

Gasoline Particulate Filters as an Effective Tool to Reduce Particulate and Polycyclic Aromatic Hydrocarbon Emissions from Gasoline Direct Injection (GDI) Vehicles: A Case Study with Two GDI Vehicles.

PubMed

Yang, Jiacheng; Roth, Patrick; Durbin, Thomas D; Johnson, Kent C; Cocker, David R; Asa-Awuku, Akua; Brezny, Rasto; Geller, Michael; Karavalakis, Georgios

2018-03-06

We assessed the gaseous, particulate, and genotoxic pollutants from two current technology gasoline direct injection vehicles when tested in their original configuration and with a catalyzed gasoline particulate filter (GPF). Testing was conducted over the LA92 and US06 Supplemental Federal Test Procedure (US06) driving cycles on typical California E10 fuel. The use of a GPF did not show any fuel economy and carbon dioxide (CO 2 ) emission penalties, while the emissions of total hydrocarbons (THC), carbon monoxide (CO), and nitrogen oxides (NOx) were generally reduced. Our results showed dramatic reductions in particulate matter (PM) mass, black carbon, and total and solid particle number emissions with the use of GPFs for both vehicles over the LA92 and US06 cycles. Particle size distributions were primarily bimodal in nature, with accumulation mode particles dominating the distribution profile and their concentrations being higher during the cold-start period of the cycle. Polycyclic aromatic hydrocarbons (PAHs) and nitrated PAHs were quantified in both the vapor and particle phases of the PM, with the GPF-equipped vehicles practically eliminating most of these species in the exhaust. For the stock vehicles, 2-3 ring compounds and heavier 5-6 ring compounds were observed in the PM, whereas the vapor phase was dominated mostly by 2-3 ring aromatic compounds.

Strand specific RNA-sequencing and membrane lipid profiling reveals growth phase-dependent cold stress response mechanisms in Listeria monocytogenes

PubMed Central

Hingston, Patricia; Chen, Jessica; Allen, Kevin; Truelstrup Hansen, Lisbeth

2017-01-01

The human pathogen Listeria monocytogenes continues to pose a challenge in the food industry, where it is known to contaminate ready-to-eat foods and grow during refrigerated storage. Increased knowledge of the cold-stress response of this pathogen will enhance the ability to control it in the food-supply-chain. This study utilized strand-specific RNA sequencing and whole cell fatty acid (FA) profiling to characterize the bacterium’s cold stress response. RNA and FAs were extracted from a cold-tolerant strain at five time points between early lag phase and late stationary-phase, both at 4°C and 20°C. Overall, more genes (1.3×) were suppressed than induced at 4°C. Late stationary-phase cells exhibited the greatest number (n = 1,431) and magnitude (>1,000-fold) of differentially expressed genes (>2-fold, p<0.05) in response to cold. A core set of 22 genes was upregulated at all growth phases, including nine genes required for branched-chain fatty acid (BCFA) synthesis, the osmolyte transporter genes opuCBCD, and the internalin A and D genes. Genes suppressed at 4°C were largely associated with cobalamin (B12) biosynthesis or the production/export of cell wall components. Antisense transcription accounted for up to 1.6% of total mapped reads with higher levels (2.5×) observed at 4°C than 20°C. The greatest number of upregulated antisense transcripts at 4°C occurred in early lag phase, however, at both temperatures, antisense expression levels were highest in late stationary-phase cells. Cold-induced FA membrane changes included a 15% increase in the proportion of BCFAs and a 15% transient increase in unsaturated FAs between lag and exponential phase. These increases probably reduced the membrane phase transition temperature until optimal levels of BCFAs could be produced. Collectively, this research provides new information regarding cold-induced membrane composition changes in L. monocytogenes, the growth-phase dependency of its cold-stress regulon, and the active roles of antisense transcripts in regulating its cold stress response. PMID:28662112

Strand specific RNA-sequencing and membrane lipid profiling reveals growth phase-dependent cold stress response mechanisms in Listeria monocytogenes.

PubMed

Hingston, Patricia; Chen, Jessica; Allen, Kevin; Truelstrup Hansen, Lisbeth; Wang, Siyun

2017-01-01

The human pathogen Listeria monocytogenes continues to pose a challenge in the food industry, where it is known to contaminate ready-to-eat foods and grow during refrigerated storage. Increased knowledge of the cold-stress response of this pathogen will enhance the ability to control it in the food-supply-chain. This study utilized strand-specific RNA sequencing and whole cell fatty acid (FA) profiling to characterize the bacterium's cold stress response. RNA and FAs were extracted from a cold-tolerant strain at five time points between early lag phase and late stationary-phase, both at 4°C and 20°C. Overall, more genes (1.3×) were suppressed than induced at 4°C. Late stationary-phase cells exhibited the greatest number (n = 1,431) and magnitude (>1,000-fold) of differentially expressed genes (>2-fold, p<0.05) in response to cold. A core set of 22 genes was upregulated at all growth phases, including nine genes required for branched-chain fatty acid (BCFA) synthesis, the osmolyte transporter genes opuCBCD, and the internalin A and D genes. Genes suppressed at 4°C were largely associated with cobalamin (B12) biosynthesis or the production/export of cell wall components. Antisense transcription accounted for up to 1.6% of total mapped reads with higher levels (2.5×) observed at 4°C than 20°C. The greatest number of upregulated antisense transcripts at 4°C occurred in early lag phase, however, at both temperatures, antisense expression levels were highest in late stationary-phase cells. Cold-induced FA membrane changes included a 15% increase in the proportion of BCFAs and a 15% transient increase in unsaturated FAs between lag and exponential phase. These increases probably reduced the membrane phase transition temperature until optimal levels of BCFAs could be produced. Collectively, this research provides new information regarding cold-induced membrane composition changes in L. monocytogenes, the growth-phase dependency of its cold-stress regulon, and the active roles of antisense transcripts in regulating its cold stress response.

Moist Climates with an Ineffective Cold Trap

NASA Astrophysics Data System (ADS)

Ding, F.; Pierrehumbert, R.

2016-12-01

The tropopause of the Earth's atmosphere behaves as a cold trap, limiting the water vapor transport from the humid sea surface to the dry regions in the atmosphere including both the upper atmosphere and the highly sub-saturated places in the free troposphere. It is hypothesized that during some period of time on Earth, the cold trap mechanism would become less effective, due to either a reduced nitrogen inventory in the atmosphere or high surface temperatures. An ineffective cold trap favors a moist upper atmosphere and will lead to rapid water loss by the ultraviolet photodissociation, which was well studied in one-dimensional models. However, the effect of an ineffective cold trap on 3D climates has not yet received much attention. Here we explore the 3D effect with an idealized general circulation model especially designed for studying condensible-rich atmospheres. We consider two scenarios based on the orbital configuration of the planet. (a) With Earth's orbital parameters, sub-saturation in the free troposphere is difficult to be produced by large-scale atmospheric flows, which implies that an ineffective cold trap also favors the onset of the runaway greenhouse. (b) For synchronous-rotating planets, water vapor is easier to be transported to the nightside, building up an atmosphere with similar column water mass as the dayside. For extrasolar habitable planets detections around M dwarfs in the future, if the water vapor contrast between the day and night side could be provided by the phase-resolved emission spectra, the contrast might be useful as a constraint for evaluating the mass of the non-condensible components in the atmosphere.

Can the capacity for isoprene emission acclimate to environmental modifications during autumn senescence in temperate deciduous tree species Populus tremula?

PubMed

Sun, Zhihong; Copolovici, Lucian; Niinemets, Ülo

2012-03-01

Changes in isoprene emission (Φ(isoprene)), and foliage photosynthetic (A) rates, isoprene precursor dimethylallyldiphosphate (DMADP), and nitrogen and carbon contents were studied from late summer to intensive leaf fall in Populus tremula to gain insight into the emission controls by temperature and endogenous, senescence-induced, modifications. Methanol emissions, characterizing degradation of cell wall pectins, were also measured. A rapid reduction in Φ(isoprene) and A of 60-70% of the initial value was observed in response to a rapid reduction of ambient temperature by ca. 15°C (cold stress). Later phases of senescence were associated with further reductions in Φ(isoprene) and A, with simultaneous major decrease in nitrogen content. However, during episodes of temperature increase, A and in particular, Φ(isoprene) partly recovered. Variation in Φ(isoprene) during senescence was correlated with average temperature of preceding days, with the highest degree of explained variance observed with average temperature of 6 days. Throughout the study, methanol emissions were small, but a large burst of methanol emission was associated with leaf yellowing and abscission. Overall, these data demonstrate that the capacity for isoprene emission can adjust to environmental conditions in senescing leaves as well, but the responsiveness is low compared with mid-season and is also affected by stress.

Effects of δ phase and cold drawing ratio on the LCF properties of alloy 718 wire

NASA Astrophysics Data System (ADS)

Jeong, Yong-Kwon; Jo, Chang-Yong; Kim, In-Bae

2000-10-01

The effects of the amount and distribution of δ particles on the low cycle fatigue (LCF) properties of alloy 718 wire were investigated. The amount and distribution of δ particles were controlled by cold drawing followed by a variety of agings. As the cold drawing ratio and aging time at 1116K increased, the well developed granular δ particles increased in amount and their distribution at grain/twin boundaries became more uniform. Regardless of the aging conditions, the LCF life increased as the cold drawing ratio increased. The granular particles precipitated along the grain boundary also improved the LCF life of alloy 718 wire since they inhibited crack propagation. After Merrick heat treatment, 50% of the cold drawn wire displayed lower 698K tensile and yield strength than 30% of the cold drawn wire. This was because the higher strain induced by the cold drawing prior to the first aging at 1116K appeared to promote the precipitation of the δ phase during aging, which has no influence on the strength of the material but has same stoichiometry with the γ phase as Ni3Nb and, as a result, the higher strain precipitated a smaller quantity of γ particles with subsequent aging, which is a major hardening phase of the alloy. Cold drawing also lowered the precipitation temperature of the δ phase.

Gas- and particle-phase primary emissions from in-use, on-road gasoline and diesel vehicles

NASA Astrophysics Data System (ADS)

May, Andrew A.; Nguyen, Ngoc T.; Presto, Albert A.; Gordon, Timothy D.; Lipsky, Eric M.; Karve, Mrunmayi; Gutierrez, Alváro; Robertson, William H.; Zhang, Mang; Brandow, Christopher; Chang, Oliver; Chen, Shiyan; Cicero-Fernandez, Pablo; Dinkins, Lyman; Fuentes, Mark; Huang, Shiou-Mei; Ling, Richard; Long, Jeff; Maddox, Christine; Massetti, John; McCauley, Eileen; Miguel, Antonio; Na, Kwangsam; Ong, Richard; Pang, Yanbo; Rieger, Paul; Sax, Todd; Truong, Tin; Vo, Thu; Chattopadhyay, Sulekha; Maldonado, Hector; Maricq, M. Matti; Robinson, Allen L.

2014-05-01

Tailpipe emissions from sixty-four unique light-duty gasoline vehicles (LDGVs) spanning model years 1987-2012, two medium-duty diesel vehicles and three heavy-duty diesel vehicles with varying levels of aftertreatment were characterized at the California Air Resources Board Haagen-Smit and Heavy-Duty Engine Testing Laboratories. Each vehicle was tested on a chassis dynamometer using a constant volume sampler, commercial fuels and standard duty cycles. Measurements included regulated pollutants such as carbon monoxide (CO), total hydrocarbons (THC), nitrogen oxides (NOx), and particulate matter (PM). Off-line analyses were performed to speciate gas- and particle-phase emissions. The data were used to investigate trends in emissions with vehicle age and to quantify the effects of different aftertreatment technologies on diesel vehicle emissions (e.g., with and without a diesel particulate filter). On average, newer LDGVs that met the most recent emissions standards had substantially lower emissions of regulated gaseous pollutants (CO, THC and NOx) than older vehicles. For example, THC emissions from the median LDGV that met the LEV2 standard was roughly a factor of 10 lower than the median pre-LEV vehicle; there were also substantial reductions in NOx (factor of ∼100) and CO (factor of ∼10) emissions from pre-LEV to LEV2 vehicles. However, reductions in LDGV PM mass emissions were much more modest. For example, PM emission from the median LEV2 vehicle was only a factor of three lower than the median pre-LEV vehicle, mainly due to the reductions in organic carbon emissions. In addition, LEV1 and LEV2 LDGVs had similar PM emissions. Catalyzed diesel particulate filters reduced CO, THC and PM emissions from HDDVs by one to two orders of magnitude. Comprehensive organic speciation was performed to quantify priority air toxic emissions and to estimate the secondary organic aerosol (SOA) formation potential. The data suggest that the SOA production from cold-start LDGVs exhaust will likely exceed primary PM emissions from LDGVs and could potentially exceed SOA formation from on-road diesel vehicles.

40 CFR 1060.102 - What permeation emission control requirements apply for fuel lines?

Code of Federal Regulations, 2014 CFR

2014-07-01

... handheld Small SI engines installed in cold-weather equipment must meet the standards for EPA Cold-Weather... when measured according to the test procedure described in § 1060.515. (3) EPA Cold-Weather Fuel Lines... described in § 1060.515: Table 1 to § 1060.102—Permeation Standards for EPA Cold-Weather Fuel Lines Model...

Secondary Organic Aerosol Production from Gasoline Vehicle Exhaust: Effects of Engine Technology, Cold Start, and Emission Certification Standard.

PubMed

Zhao, Yunliang; Lambe, Andrew T; Saleh, Rawad; Saliba, Georges; Robinson, Allen L

2018-02-06

Secondary organic aerosol (SOA) formation from dilute exhaust from 16 gasoline vehicles was investigated using a potential aerosol mass (PAM) oxidation flow reactor during chassis dynamometer testing using the cold-start unified cycle (UC). Ten vehicles were equipped with gasoline direct injection engines (GDI vehicles) and six with port fuel injection engines (PFI vehicles) certified to a wide range of emissions standards. We measured similar SOA production from GDI and PFI vehicles certified to the same emissions standard; less SOA production from vehicles certified to stricter emissions standards; and, after accounting for differences in gas-particle partitioning, similar effective SOA yields across different engine technologies and certification standards. Therefore the ongoing, dramatic shift from PFI to GDI vehicles in the United States should not alter the contribution of gasoline vehicles to ambient SOA and the natural replacement of older vehicles with newer ones certified to stricter emissions standards should reduce atmospheric SOA levels. Compared to hot operations, cold-start exhaust had lower effective SOA yields, but still contributed more SOA overall because of substantially higher organic gas emissions. We demonstrate that the PAM reactor can be used as a screening tool for vehicle SOA production by carefully accounting for the effects of the large variations in emission rates.

CARMA observations of Galactic cold cores: searching for spinning dust emission

NASA Astrophysics Data System (ADS)

Tibbs, C. T.; Paladini, R.; Cleary, K.; Muchovej, S. J. C.; Scaife, A. M. M.; Stevenson, M. A.; Laureijs, R. J.; Ysard, N.; Grainge, K. J. B.; Perrott, Y. C.; Rumsey, C.; Villadsen, J.

2015-11-01

We present the first search for spinning dust emission from a sample of 34 Galactic cold cores, performed using the CARMA interferometer. For each of our cores, we use photometric data from the Herschel Space Observatory to constrain bar{N}H, bar{T}d, bar{n}H, and bar{G}0. By computing the mass of the cores and comparing it to the Bonnor-Ebert mass, we determined that 29 of the 34 cores are gravitationally unstable and undergoing collapse. In fact, we found that six cores are associated with at least one young stellar object, suggestive of their protostellar nature. By investigating the physical conditions within each core, we can shed light on the cm emission revealed (or not) by our CARMA observations. Indeed, we find that only three of our cores have any significant detectable cm emission. Using a spinning dust model, we predict the expected level of spinning dust emission in each core and find that for all 34 cores, the predicted level of emission is larger than the observed cm emission constrained by the CARMA observations. Moreover, even in the cores for which we do detect cm emission, we cannot, at this stage, discriminate between free-free emission from young stellar objects and spinning dust emission. We emphasize that although the CARMA observations described in this analysis place important constraints on the presence of spinning dust in cold, dense environments, the source sample targeted by these observations is not statistically representative of the entire population of Galactic cores.

Characterizing the Multi-Phase Origin of the [CII] Emission in M101 and NGC 6946

NASA Astrophysics Data System (ADS)

Tarantino, Elizabeth; Bolatto, Alberto; Herrera-Camus, Rodrigo

2018-01-01

The bright far-infrared line [CII] is a dominant cooling channel of the neutral interstellar medium (ISM) and is a tracer of star formation. However, [CII] can be excited in different environments of the ISM, such as in dense photodissociation regions (PDRs), the cold/warm neutral medium (CNM/WNM), and the warm ionized medium (WIM). Separating the [CII] emission into its multiple components is vital for understanding star formation and for using [CII] as a star formation tracer. We present spectrally resolved SOFIA/GREAT data of the 158 μm [CII] emission, as well as ancillary HI and CO 2-1 data, to disentangle the multiple phases of the ISM. We use 18 pointings that sample the range of different environments present in these galaxies, including star formation activity, metallicity, radiation field strength, and gas content. We find that on average the [CII] is more associated with the dense CO gas coming from PDRs than the neutral medium, consistent with other results in the literature. Additionally, the [CII] observations allow us to access the “CO-faint” molecular gas in regions that have too low of a metallicty to produce CO. This adds to the small number of studies that have explored this “CO-faint” regime.

40 CFR 600.113-08 - Fuel economy calculations for FTP, HFET, US06, SC03 and cold temperature FTP tests.

Code of Federal Regulations, 2013 CFR

2013-07-01

... EMISSIONS OF MOTOR VEHICLES Fuel Economy and Carbon-Related Exhaust Emission Test Procedures § 600.113-08 Fuel economy calculations for FTP, HFET, US06, SC03 and cold temperature FTP tests. The Administrator... specific gravity, carbon weight fraction and net heating value of the test fuel must be determined. The FTP...

Comparison of real-world and certification emission rates for light duty gasoline vehicles.

PubMed

Khan, Tanzila; Frey, H Christopher

2018-05-01

U.S. light duty vehicles are subject to the U.S. Environmental Protection Agency (EPA) emission standards. Emission compliance is determined by certification testing of selected emissions from representative vehicles on standard driving cycles using chassis dynamometers. Test results are also used in many emission inventories. The dynamometer based emission rates are adjusted to provide the certification levels (CL), which must be lower than the standards for compliance. Although standard driving cycles are based on specific observations of real-world driving, they are not necessarily real-world representative. A systematic comparison of the real-world emission rates of U.S. light duty gasoline vehicles (LDGVs) versus CL, and emission standards has not been previously reported. The purpose of this work is to compare regulatory limits (both CLs and emission standards) and the real-world emissions of LDGVs. The sensitivity of the comparisons to cold start emission was assessed. Portable Emission Measurement Systems (PEMS) were used to measure hot stabilized exhaust emissions of 122 LDGVs on a specified 110 mile test route. Cold start emissions were measured with PEMS for a selected vehicle sample of 32 vehicles. Emissions were measured for carbon dioxide (CO 2 ), carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxides (NO x ). For each vehicle, a Vehicle Specific Power (VSP) modal emission rate model was developed. The VSP modal rates were weighted by the standard driving cycles and real-world driving cycles to estimate the respective cycle average emission rates (CAERs). Measured vehicles were matched with certification test vehicles for comparison. For systematic trends in comparison, vehicles were classified into four groups based on the Tier 1 and Tier 2 emission regulation, and the vehicle type such as passenger car and passenger truck. Depending on the cycle-pollutant and the vehicle groups, hot stabilized CAERs are on average either statistically significantly higher than or significantly not different from the CLs, with the exception of CO on the US06 cycle, for which real-world rates are lower than CLs. Compared to the emission standards, hot stabilized CAERs are on average significantly lower. However, comparisons of CAERs and standards are sensitive to cold start emissions. For some combinations of pollutants and vehicle groups, cold start inclusive CAERs are higher than the corresponding CLs and as high as the standards. The CLs, which are based on standard driving cycles, tend to underestimate real-world emission rates. Therefore, emission inventory estimates using certification test results are potentially underestimated. Copyright © 2017 Elsevier B.V. All rights reserved.

Alternative Fuels Data Center: Biodiesel Blends

Science.gov Websites

popular because it represents a good balance of cost, emissions, cold-weather performance, materials increase nitrogen oxides emissions, although it greatly reduces other toxic emissions. B100 requires

Acquisition parameters optimization of a transmission electron forward scatter diffraction system in a cold-field emission scanning electron microscope for nanomaterials characterization.

PubMed

Brodusch, Nicolas; Demers, Hendrix; Trudeau, Michel; Gauvin, Raynald

2013-01-01

Transmission electron forward scatter diffraction (t-EFSD) is a new technique providing crystallographic information with high resolution on thin specimens by using a conventional electron backscatter diffraction (EBSD) system in a scanning electron microscope. In this study, the impact of tilt angle, working distance, and detector distance on the Kikuchi pattern quality were investigated in a cold-field emission scanning electron microscope (CFE-SEM). We demonstrated that t-EFSD is applicable for tilt angles ranging from -20° to -40°. Working distance (WD) should be optimized for each material by choosing the WD for which the EBSD camera screen illumination is the highest, as the number of detected electrons on the screen is directly dependent on the scattering angle. To take advantage of the best performances of the CFE-SEM, the EBSD camera should be close to the sample and oriented towards the bottom to increase forward scattered electron collection efficiency. However, specimen chamber cluttering and beam/mechanical drift are important limitations in the CFE-SEM used in this work. Finally, the importance of t-EFSD in materials science characterization was illustrated through three examples of phase identification and orientation mapping. © Wiley Periodicals, Inc.

Statistical properties of the polarized emission of Planck Galactic cold clumps

NASA Astrophysics Data System (ADS)

Ristorcelli, Isabelle; Planck Collaboration

2015-08-01

The Galactic magnetic fields are considered as one of the key components regulating star formation, but their actual role on the dense cores formation and evolution remains today an open question.Dust polarized continuum emission is particularly well suited to probe the dense and cold medium and study the magnetic field structure. Such observations also provide tight constraints to better understand the efficiency of the dust alignment along the magnetic field lines, which in turn relate on our grasp to properly interpret the B-field properties.With the Planck all-sky survey of dust submillimeter emission in intensity and polarization, we can investigate the intermediate scales, between that of molecular cloud and of prestellar cores, and perform a statistical analysis on the polarization properties of cold clumps.Combined with the IRAS map at 100microns, the Planck survey has allowed to build the first all-sky catalogue of Galactic Cold Clumps (PGCC, Planck 2015 results XXVIII 2015). The corresponding 13188 sources cover a broad range in physical properties, and correspond to different evolutionary stages, from cold and starless clumps, nearby cores, to young protostellar objects still embedded in their cold surrounding cloud.I will present the main results of our polarization analysis obtained on different samples of sources from the PGCC catalogue, based on the 353GHz polarized emission measured with Planck. The statistical properties are derived from a stacking method, using optimized estimators for the polarization fraction and angle parameters. These properties are determined and compared according to the nature of the sources (starless or YSOs), their size or density range. Finally, I will present a comparison of our results with predictions from MHD simulations of clumps including radiative transfer and the dust radiative torque alignment mechanism.

40 CFR 86.208-94 - Dynamometer.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Passenger Vehicles; Cold Temperature Test Procedures § 86.208-94 Dynamometer. (a) For testing that is... the manufacturer, a dynamometer with different characteristics may be used provided cold CO emissions...

40 CFR 86.208-94 - Dynamometer.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Passenger Vehicles; Cold Temperature Test Procedures § 86.208-94 Dynamometer. (a) For testing that is... the manufacturer, a dynamometer with different characteristics may be used provided cold CO emissions...

40 CFR 86.201-11 - General applicability.

Code of Federal Regulations, 2013 CFR

2013-07-01

...-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.201-11 General applicability. (a) This subpart describes procedures for determining the cold temperature carbon monoxide (CO) emissions from 1994...

40 CFR 86.201-94 - General applicability.

Code of Federal Regulations, 2013 CFR

2013-07-01

...-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.201-94 General applicability. (a) This subpart describes procedures for determining the cold temperature carbon monoxide (CO) emission from 1994...

40 CFR 86.208-94 - Dynamometer.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Passenger Vehicles; Cold Temperature Test Procedures § 86.208-94 Dynamometer. (a) For testing that is... the manufacturer, a dynamometer with different characteristics may be used provided cold CO emissions...

40 CFR 86.201-94 - General applicability.

Code of Federal Regulations, 2012 CFR

2012-07-01

...-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.201-94 General applicability. (a) This subpart describes procedures for determining the cold temperature carbon monoxide (CO) emission from 1994...

40 CFR 86.201-94 - General applicability.

Code of Federal Regulations, 2011 CFR

2011-07-01

...-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.201-94 General applicability. (a) This subpart describes procedures for determining the cold temperature carbon monoxide (CO) emission from 1994...

40 CFR 86.201-11 - General applicability.

Code of Federal Regulations, 2011 CFR

2011-07-01

...-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.201-11 General applicability. (a) This subpart describes procedures for determining the cold temperature carbon monoxide (CO) emissions from 1994...

40 CFR 86.201-11 - General applicability.

Code of Federal Regulations, 2012 CFR

2012-07-01

...-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.201-11 General applicability. (a) This subpart describes procedures for determining the cold temperature carbon monoxide (CO) emissions from 1994...

Single photon infrared emission spectroscopy: a study of IR emission from UV laser excited PAHs between 3 and 15 micrometers

NASA Technical Reports Server (NTRS)

Cook, D. J.; Schlemmer, S.; Balucani, N.; Wagner, D. R.; Harrison, J. A.; Steiner, B.; Saykally, R. J.

1998-01-01

Single-photon infrared emission spectroscopy (SPIRES) has been used to measure emission spectra from polycyclic aromatic hydrocarbons (PAHs). A supersonic free-jet expansion has been used to provide emission spectra of rotationally cold and vibrationally excited naphthalene and benzene. Under these conditions, the observed width of the 3.3-micrometers (C-H stretch) band resembles the bandwidths observed in experiments in which emission is observed from naphthalene with higher rotational energy. To obtain complete coverage of IR wavelengths relevant to the unidentified infrared bands (UIRs), UV laser-induced desorption was used to generate gas-phase highly excited PAHs. Lorentzian band shapes were convoluted with the monochromator-slit function in order to determine the widths of PAH emission bands under astrophysically relevant conditions. Bandwidths were also extracted from bands consisting of multiple normal modes blended together. These parameters are grouped according to the functional groups mostly involved in the vibration, and mean bandwidths are obtained. These bandwidths are larger than the widths of the corresponding UIR bands. However, when the comparison is limited to the largest PAHs studied, the bandwidths are slightly smaller than the corresponding UIR bands. These parameters can be used to model emission spectra from PAH cations and cations of larger PAHs, which are better candidate carriers of the UIRs.

Tidally controlled gas bubble emissions: A comprehensive study using long-term monitoring data from the NEPTUNE cabled observatory offshore Vancouver Island

NASA Astrophysics Data System (ADS)

Römer, Miriam; Riedel, Michael; Scherwath, Martin; Heesemann, Martin; Spence, George D.

2016-09-01

Long-term monitoring over 1 year revealed high temporal variability of gas emissions at a cold seep in 1250 m water depth offshore Vancouver Island, British Columbia. Data from the North East Pacific Time series Underwater Networked Experiment observatory operated by Ocean Networks Canada were used. The site is equipped with a 260 kHz Imagenex sonar collecting hourly data, conductivity-temperature-depth sensors, bottom pressure recorders, current meter, and an ocean bottom seismograph. This enables correlation of the data and analyzing trigger mechanisms and regulating criteria of gas discharge activity. Three periods of gas emission activity were observed: (a) short activity phases of few hours lasting several months, (b) alternating activity and inactivity of up to several day-long phases each, and (c) a period of several weeks of permanent activity. These periods can neither be explained by oceanographic conditions nor initiated by earthquakes. However, we found a clear correlation of gas emission with bottom pressure changes controlled by tides. Gas bubbles start emanating during decreasing tidal pressure. Tidally induced pressure changes also influence the subbottom fluid system by shifting the methane solubility resulting in exsolution of gas during falling tides. These pressure changes affect the equilibrium of forces allowing free gas in sediments to emanate into the water column at decreased hydrostatic load. We propose a model for the fluid system at the seep, fueled by a constant subsurface methane flux and a frequent tidally controlled discharge of gas bubbles into the ocean, transferable to other gas emission sites in the world's oceans.

Parametrically Optimized Carbon Nanotube-Coated Cold Cathode Spindt Arrays

PubMed Central

Yuan, Xuesong; Cole, Matthew T.; Zhang, Yu; Wu, Jianqiang; Milne, William I.; Yan, Yang

2017-01-01

Here, we investigate, through parametrically optimized macroscale simulations, the field electron emission from arrays of carbon nanotube (CNT)-coated Spindts towards the development of an emerging class of novel vacuum electron devices. The present study builds on empirical data gleaned from our recent experimental findings on the room temperature electron emission from large area CNT electron sources. We determine the field emission current of the present microstructures directly using particle in cell (PIC) software and present a new CNT cold cathode array variant which has been geometrically optimized to provide maximal emission current density, with current densities of up to 11.5 A/cm2 at low operational electric fields of 5.0 V/μm. PMID:28336845

Large turbulent reservoirs of cold molecular gas around high-redshift starburst galaxies.

PubMed

Falgarone, E; Zwaan, M A; Godard, B; Bergin, E; Ivison, R J; Andreani, P M; Bournaud, F; Bussmann, R S; Elbaz, D; Omont, A; Oteo, I; Walter, F

2017-08-24

Starburst galaxies at the peak of cosmic star formation are among the most extreme star-forming engines in the Universe, producing stars over about 100 million years (ref. 2). The star-formation rates of these galaxies, which exceed 100 solar masses per year, require large reservoirs of cold molecular gas to be delivered to their cores, despite strong feedback from stars or active galactic nuclei. Consequently, starburst galaxies are ideal for studying the interplay between this feedback and the growth of a galaxy. The methylidyne cation, CH + , is a most useful molecule for such studies because it cannot form in cold gas without suprathermal energy input, so its presence indicates dissipation of mechanical energy or strong ultraviolet irradiation. Here we report the detection of CH + (J = 1-0) emission and absorption lines in the spectra of six lensed starburst galaxies at redshifts near 2.5. This line has such a high critical density for excitation that it is emitted only in very dense gas, and is absorbed in low-density gas. We find that the CH + emission lines, which are broader than 1,000 kilometres per second, originate in dense shock waves powered by hot galactic winds. The CH + absorption lines reveal highly turbulent reservoirs of cool (about 100 kelvin), low-density gas, extending far (more than 10 kiloparsecs) outside the starburst galaxies (which have radii of less than 1 kiloparsec). We show that the galactic winds sustain turbulence in the 10-kiloparsec-scale environments of the galaxies, processing these environments into multiphase, gravitationally bound reservoirs. However, the mass outflow rates are found to be insufficient to balance the star-formation rates. Another mass input is therefore required for these reservoirs, which could be provided by ongoing mergers or cold-stream accretion. Our results suggest that galactic feedback, coupled jointly to turbulence and gravity, extends the starburst phase of a galaxy instead of quenching it.

Secondary organic aerosol formation from road vehicle emissions

NASA Astrophysics Data System (ADS)

Pieber, Simone M.; Platt, Stephen M.; El Haddad, Imad; Zardini, Alessandro A.; Suarez-Bertoa, Ricardo; Slowik, Jay G.; Huang, Ru-Jin; Hellebust, Stig; Temime-Roussel, Brice; Marchand, Nicolas; Drinovec, Luca; Mocnik, Grisa; Baltensperger, Urs; Astorga, Covadogna; Prévôt, André S. H.

2014-05-01

Organic aerosol particles (OA) are a major fraction of the submicron particulate matter. OA consists of directly emitted primary (POA) and secondary OA (SOA). SOA is formed in-situ in the atmosphere via the reaction of volatile organic precursors. The partitioning of SOA species depends not only on the exposure to oxidants, but for instance also on temperature, relative humidity (RH), and the absorptive mass chemical composition (presence of inorganics) and concentration. Vehicle exhaust is a known source of POA and likely contributes to SOA formation in urban areas [1;2]. This has recently been estimated by (i) analyzing ambient data from urban areas combined with fuel consumption data [3], (ii) by examining the chemical composition of raw fuels [4], or (iii) smog chamber studies [5, 6]. Contradictory and thus somewhat controversial results in the relative quantity of SOA from diesel vs. gasoline vehicle exhaust were observed. In order to elucidate the impact of variable ambient conditions on the potential SOA formation of vehicle exhaust, and its relation to the emitted gas phase species, we studied SOA formed from the exhaust of passenger cars and trucks as a function of fuel and engine type (gasoline, diesel) at different temperatures (T 22 vs. -7oC) and RH (40 vs. 90%), as well as with different levels of inorganic salt concentrations. The exhaust was sampled at the tailpipe during regulatory driving cycles on chassis dynamometers, diluted (200 - 400x) and introduced into the PSI mobile smog chamber [6], where the emissions were subjected to simulated atmospheric ageing. Particle phase instruments (HR-ToF-AMS, aethalometers, CPC, SMPS) and gas phase instruments (PTR-TOF-MS, CO, CO2, CH4, THC, NH3 and other gases) were used online during the experiments. We found that gasoline emissions, because of cold starts, were generally larger than diesel, especially during cold temperatures driving cycles. Gasoline vehicles also showed the highest SOA formation. Furthermore, we observed that vehicle emissions and SOA are significantly affected by temperature and RH: doubling the RH in the chamber resulted in significantly increased SOA formation. Primary emissions and secondary aerosol formation from diesel and gasoline vehicles will be compared at different temperature and RH. Also the interaction and influence of inorganics on organics will be discussed. References: [1] Robinson, A.L., et al. (2007) Science 315, 1259. [2] Weitkamp, E.A., et al. (2007) Environ. Sci. Technol. 41, 6969. [3] Bahreini, R., et al. (2012) Geophys. Res. Lett. 39, L06805. [4] Gentner, D.R. et al. (2012) PNAS 109, 18318. [5] Gordon, T.D. et al. (2013) Atmos. Chem. Phys. Discuss 13, 23173. [6] Platt, S.M., et al. (2013) Atmos. Chem. Phys. Discuss. 12, 28343.

Advancing Methods for Estimating Soil Nitrous Oxide Emissions by Incorporating Freeze-Thaw Cycles into a Tier 3 Model-Based Assessment

NASA Astrophysics Data System (ADS)

Ogle, S. M.; DelGrosso, S.; Parton, W. J.

2017-12-01

Soil nitrous oxide emissions from agricultural management are a key source of greenhouse gas emissions in many countries due to the widespread use of nitrogen fertilizers, manure amendments from livestock production, planting legumes and other practices that affect N dynamics in soils. In the United States, soil nitrous oxide emissions have ranged from 250 to 280 Tg CO2 equivalent from 1990 to 2015, with uncertainties around 20-30 percent. A Tier 3 method has been used to estimate the emissions with the DayCent ecosystem model. While the Tier 3 approach is considerably more accurate than IPCC Tier 1 methods, there is still the possibility of biases in emission estimates if there are processes and drivers that are not represented in the modeling framework. Furthermore, a key principle of IPCC guidance is that inventory compilers estimate emissions as accurately as possible. Freeze-thaw cycles and associated hot moments of nitrous oxide emissions are one of key drivers influencing emissions in colder climates, such as the cold temperate climates of the upper Midwest and New England regions of the United States. Freeze-thaw activity interacts with management practices that are increasing N availability in the plant-soil system, leading to greater nitrous oxide emissions during transition periods from winter to spring. Given the importance of this driver, the DayCent model has been revised to incorproate freeze-thaw cycles, and the results suggests that including this driver can significantly modify the emissions estimates in cold temperate climate regions. Consequently, future methodological development to improve estimation of nitrous oxide emissions from soils would benefit from incorporating freeze-thaw cycles into the modeling framework for national territories with a cold climate.

Light absorption of organic carbon emitted from burning wood, charcoal, and kerosene in household cookstoves.

PubMed

Xie, Mingjie; Shen, Guofeng; Holder, Amara L; Hays, Michael D; Jetter, James J

2018-05-02

Household cookstove emissions are an important source of carbonaceous aerosols globally. The light-absorbing organic carbon (OC), also termed brown carbon (BrC), from cookstove emissions can impact the Earth's radiative balance, but is rarely investigated. In this work, PM 2.5 filter samples were collected during combustion experiments with red oak wood, charcoal, and kerosene in a variety of cookstoves mainly at two water boiling test phases (cold start CS, hot start HS). Samples were extracted in methanol and extracts were examined using spectrophotometry. The mass absorption coefficients (MAC λ , m 2 g -1 ) at five wavelengths (365, 400, 450, 500, and 550 nm) were mostly inter-correlated and were used as a measurement proxy for BrC. The MAC 365 for red oak combustion during the CS phase correlated strongly to the elemental carbon (EC)/OC mass ratio, indicating a dependency of BrC absorption on burn conditions. The emissions from cookstoves burning red oak have an average MAC λ 2-6 times greater than those burning charcoal and kerosene, and around 3-4 times greater than that from biomass burning measured in previous studies. These results suggest that residential cookstove emissions could contribute largely to ambient BrC, and the simulation of BrC radiative forcing in climate models for biofuel combustion in cookstoves should be treated specifically and separated from open biomass burning. Copyright © 2018 Elsevier Ltd. All rights reserved.

Correlation of Microstructure and Texture in a Two-Phase High-Mn Twinning-Induced Plasticity Steel During Cold Rolling

NASA Astrophysics Data System (ADS)

Ashiq, Mohammad; Dhekne, Pushkar; Hamada, Atef Saad; Sahu, Puspendu; Mahato, B.; Minz, R. K.; Ghosh Chowdhury, Sandip; Pentti Karjalainen, L.

2017-10-01

The evolution of microstructure and texture of a two-phase austenite-ferrite twinning-induced plasticity steel during cold rolling was investigated and different deformation mechanisms were found to become active with increasing thickness reductions. Optical microscopy showed the formation of brass-type shear bands across several austenite grains at reductions greater than 50 pct. TEM observations reveal the presence of deformation twinning in austenite. The austenite phase initially shows the Cu-type texture, i.e., Cu {1 1 2}〈1 1 1〉, Goss {0 1 1}〈1 0 0〉 with a spread toward Brass {1 1 0}〈1 1 2〉. With continued cold rolling, the Cu {1 1 2}〈1 1 1〉 component moves toward CuT component {552}〈115〉 and the other two components increase in intensity. There is also emergence of {111} fiber after 90 pct cold rolling. The ferrite phase exhibits the evolution of ND-rotated Cube component {001}〈110〉 along with 〈110〉 fiber at lower as well as at higher rolling reductions. An exception is at 75 pct reduction, when the ferrite texture contains {111} fiber in place of 〈110〉 fiber with a weak rotated-Cube component. Phase fraction analysis by X-ray diffraction indicates a decrease in the austenite fraction up to 75 pct reduction followed by an increase at 90 pct reduction. After 90 pct cold rolling, the phase fraction is similar to that of the "as-received" state. Elongated grains of ferrite phase in finer dimensions after 90 pct cold rolling indicate softening within that phase; at similar stage, there are finer scale austenite grains mostly at the grain boundaries. The above has been suggested to be related with the adiabatic heating during cold rolling due to the high strain hardening of the austenite phase.

Gas-phase chemical characteristics of Asian emission plumes observed during ITCT 2K2 over the eastern North Pacific Ocean

NASA Astrophysics Data System (ADS)

Nowak, J. B.; Parrish, D. D.; Neuman, J. A.; Holloway, J. S.; Cooper, O. R.; Ryerson, T. B.; Nicks, D. K.; Flocke, F.; Roberts, J. M.; Atlas, E.; de Gouw, J. A.; Donnelly, S.; Dunlea, E.; Hübler, G.; Huey, L. G.; Schauffler, S.; Tanner, D. J.; Warneke, C.; Fehsenfeld, F. C.

2004-12-01

The gas-phase chemical characteristics of emission plumes transported from Asia across the Pacific Ocean observed during the Intercontinental Transport and Chemical Transformation experiment in 2002 (ITCT 2K2) are described. Plumes measured in the troposphere from an aircraft were separated from the background air in data analysis using 1-s measurements of carbon monoxide (CO), total reactive nitrogen (NOy), and other gas-phase species along with back trajectory analysis. On the basis of these measurements, Asian transport plumes with CO mixing ratios greater than 150 ppbv were observed on seven flights. Correlations between 1-s observations of CO, ozone (O3), and NOy are used to characterize the plumes. The NOy/CO ratios were similar in each plume and significantly lower than those derived from estimated Asian emission ratios, indicating substantial removal of soluble NOy species during transport. Observations of nitric oxide (NO), nitrogen dioxide (NO2), nitric acid (HNO3), peroxyacetyl nitrate (PAN), peroxypropionyl nitrate (PPN), and alkyl nitrates are used with the NOy measurements to further distinguish the transport plumes by their NOy partitioning. NOy was primarily in the form of PAN in plumes that were transported in cold high-latitude and high-altitude regions, whereas in plumes transported in warmer, lower latitude and altitude regions, NOy was mainly HNO3. Additional gas-phase species enhanced in these plumes include sulfuric acid, methanol, acetone, propane, and ethane. The O3/CO ratio varied among the plumes and was affected by the mixing of anthropogenic and stratospheric influences. The complexity of this mixing prevents the determination of the relative contribution of anthropogenic and stratospheric influences to the observed O3 levels.

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.

Spectroscopy of neutral and ionized PAHs. From laboratory studies to astronomical observations

NASA Technical Reports Server (NTRS)

Salama, Farid

2005-01-01

Polycyclic Aromatic Hydrocarbons (PAHs) are an important and ubiquitous component of carbon-bearing materials in space. PAHs are the best-known candidates to account for the IR emission bands (UIR bands) and PAH spectral features are now being used as new probes of the ISM. PAHs are also thought to be among the carriers of the diffuse interstellar absorption bands (DIBs). In the model dealing with the interstellar spectral features, PAHs are present as a mixture of radicals, ions and neutral species. PAH ionization states reflect the ionization balance of the medium while PAH size, composition, and structure reflect the energetic and chemical history of the medium. A major challenge for laboratory astrochemistry is to reproduce (in a realistic way) the physical conditions that are associated with the emission and absorption interstellar zones. An extensive laboratory program has been developed at NASA Ames to assess the physical and chemical properties of PAHs in such environments and to describe how they influence the radiation and energy balance in space and the interstellar chemistry. PAHs, neutrals and ions, are expanded through a pulsed discharge nozzle (PDN) and probed with high-sensitivity cavity ringdown spectroscopy (CRDS). These laboratory experiments provide unique information on the spectra of free, cold large carbon molecules and ions in the gas phase from the ultraviolet and visible range to the near-infrared range. Intrinsic band profiles and band positions of cold gas-phase PAHs can now be measured with high-sensitivity spectroscopy and directly compared to the astronomical data. Preliminary conclusions from the comparison of the laboratory data with astronomical observations of interstellar and circumstellar environments will also be discussed.

Spatial and temporal distributions of Martian north polar cold spots before, during, and after the global dust storm of 2001

USGS Publications Warehouse

Cornwall, C.; Titus, T.N.

2009-01-01

In the 1970s, Mariner and Viking observed features in the Mars northern polar region that were a few hundred kilometers in diameter with 20 fj,m brightness temperatures as low as 130 K (considerably below C02 ice sublimation temperatures). Over the past decade, studies have shown that these areas (commonly called "cold spots") are usually due to emissivity effects of frost deposits and occasionally to active C02 snowstorms. Three Mars years of Mars Global Surveyor Thermal Emission Spectrometer data were used to observe autumn and wintertime cold spot activity within the polar regions. Many cold spots formed on or near scarps of the perennial cap, probably induced by adiabatic cooling due to orographic lifting. These topographically associated cold spots were often smaller than those that were not associated with topography. We determined that initial grain sizes within the cold spots were on the order of a few millimeters, assuming the snow was uncontaminated by dust or water ice. On average, the half-life of the cold spots was 5 Julian days. The Mars global dust storm in 2001 significantly affected cold spot activity in the north polar region. Though overall perennial cap cold spot activity seemed unaffected, the distribution of cold spots did change by a decrease in the number of topographically associated cold spots and an increase in those not associated with topography. We propose that the global dust storm affected the processes that form cold spots and discuss how the global dust storm may have affected these processes. ?? 2009 by the American Geophysical Union.

Vacuum encapsulated hermetically sealed diamond amplified cathode capsule and method for making same

DOEpatents

Rao, Triveni; Walsh, John; Gangone, Elizabeth

2014-12-30

A vacuum encapsulated, hermetically sealed cathode capsule for generating an electron beam of secondary electrons, which generally includes a cathode element having a primary emission surface adapted to emit primary electrons, an annular insulating spacer, a diamond window element comprising a diamond material and having a secondary emission surface adapted to emit secondary electrons in response to primary electrons impinging on the diamond window element, a first cold-weld ring disposed between the cathode element and the annular insulating spacer and a second cold-weld ring disposed between the annular insulating spacer and the diamond window element. The cathode capsule is formed by a vacuum cold-weld process such that the first cold-weld ring forms a hermetical seal between the cathode element and the annular insulating spacer and the second cold-weld ring forms a hermetical seal between the annular spacer and the diamond window element whereby a vacuum encapsulated chamber is formed within the capsule.

The Fifth ISM Phase as Revealed by Faraday Rotation

NASA Astrophysics Data System (ADS)

Heiles, Carl E.

2011-01-01

In the diffuse ISM, phases are classically categorized as largely ionized or neutral. The neutral phases come in two flavors, the Cold and Warm Neutral Media (the CNM and WNM), which have typical temperatures 50 and 5000 K. The ionized phases also come in two flavors, again classified by temperature: the Warm and Hot Ionized Media (the WIM and the HIM), which have typical temperatures 8000 and 106 K. There lurks a fifth phase, the Warm Partially Ionized Medium (WPIM). This is not widely recognized, mainly because it's presence is hard to establish observationally. It is well represented by the Local Interstellar Cloud (LIC), whose properties are very well specified in a series of papers by Redfield and Linsky. This fifth phase has a relatively high electron column but low emission measure, so it is not easily seen in H alpha. However, if the region is permeated by a typical magnetic field ( 6 microGauss), then it can produce a recognizable signature in Faraday rotation. We show a few examples and discuss the potential for large-scale mapping of this fifth ISM phase. Support for this work was provided in part by NSF grant AST-0908572.

A COLD FLARE WITH DELAYED HEATING

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

Fleishman, Gregory D.; Pal'shin, Valentin D.; Lysenko, Alexandra L.

2016-05-10

Recently, a number of peculiar flares have been reported that demonstrate significant nonthermal particle signatures with low, if any, thermal emission, which implies a close association of the observed emission with the primary energy release/electron acceleration region. This paper presents a flare that appears “cold” at the impulsive phase, while displaying delayed heating later on. Using hard X-ray data from Konus- Wind , microwave observations by SSRT, RSTN, NoRH, and NoRP, context observations, and three-dimensional modeling, we study the energy release, particle acceleration, and transport, and the relationships between the nonthermal and thermal signatures. The flaring process is found tomore » involve the interaction between a small loop and a big loop with the accelerated particles divided roughly equally between them. Precipitation of the electrons from the small loop produced only a weak thermal response because the loop volume was small, while the electrons trapped in the big loop lost most of their energy in the coronal part of the loop, which resulted in coronal plasma heating but no or only weak chromospheric evaporation, and thus unusually weak soft X-ray emission. The energy losses of the fast electrons in the big tenuous loop were slow, which resulted in the observed delay of the plasma heating. We determined that the impulsively accelerated electron population had a beamed angular distribution in the direction of the electric force along the magnetic field of the small loop. The accelerated particle transport in the big loop was primarily mediated by turbulent waves, which is similar to other reported cold flares.« less

DOUBLE DCO{sup +} RINGS REVEAL CO ICE DESORPTION IN THE OUTER DISK AROUND IM LUP

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

Öberg, Karin I.; Loomis, Ryan; Andrews, Sean M.

2015-09-10

In a protoplanetary disk, a combination of thermal and non-thermal desorption processes regulate where volatiles are liberated from icy grain mantles into the gas phase. Non-thermal desorption should result in volatile-enriched gas in disk-regions where complete freeze-out is otherwise expected. We present Atacama Large Millimeter/Submillimeter Array observations of the disk around the young star IM Lup in 1.4 mm continuum, C{sup 18}O 2–1, H{sup 13}CO{sup +} 3–2 and DCO{sup +} 3–2 emission at ∼0.″5 resolution. The images of these dust and gas tracers are clearly resolved. The DCO{sup +} line exhibits a striking pair of concentric rings of emission thatmore » peak at radii of ∼0.″6 and 2″ (∼90 and 300 AU, respectively). Based on disk chemistry model comparison, the inner DCO{sup +} ring is associated with the balance of CO freeze-out and thermal desorption due to a radial decrease in disk temperature. The outer DCO{sup +} ring is explained by non-thermal desorption of CO ice in the low-column-density outer disk, repopulating the disk midplane with cold CO gas. The CO gas then reacts with abundant H{sub 2}D{sup +} to form the observed DCO{sup +} outer ring. These observations demonstrate that spatially resolved DCO{sup +} emission can be used to trace otherwise hidden cold gas reservoirs in the outmost disk regions, opening a new window onto their chemistry and kinematics.« less

The Evolution of Second-Phase Particles in 6111 Aluminum Alloy Processed by Hot and Cold Rolling

NASA Astrophysics Data System (ADS)

Zhang, Lixin; Wang, Yihan; Ni, Song; Chen, Gang; Li, Kai; Du, Yong; Song, Min

2018-03-01

The evolution of coarse Al9.9Fe2.65Ni1.45 phase, spherical Al12(Mn,Fe)3Si phase and rod-like Q phase in a 6111 aluminum alloy during hot and cold rolling deformation processes was systematically investigated in this work. The results showed that the coarse Al9.9Fe2.65Ni1.45 particles are mainly distributed at the grain boundaries, accompanied by the co-formation of Al12(Fe,Mn)3Si phase and Mg2Si phase, while the spherical Al12(Mn,Fe)3Si particles are mainly distributed in the grain interiors. Hot rolling has little effects on the size and distribution of both phases, but cold deformation can severely decrease the size of the particles by breaking the particles into small pieces. In addition, the temperature of 450 °C is not high enough for the dissolution of Q phase in the Al matrix, but the Q particles can be broken into small pieces due to the stress concentration during both hot and cold rolling deformation. In addition, the influences of phase evolution, dislocations and recrystallization on the mechanical properties evolution were also discussed.

Chemically synthesized boron carbon oxynitride as a new cold cathode material

NASA Astrophysics Data System (ADS)

Banerjee, Diptonil; Maity, Supratim; Chattopadhyay, K. K.

2015-11-01

Synthesis of boron carbon oxynitride (BCNO) nanosheets at different temperature from amorphous to crystalline regime has been reported. The synthesis was done by a simple molten salt process using sodium borohydride and urea as precursors. Transmission electron microscopic study confirms the formation of sheet-like structure of the as-synthesized material. The performances of the as-synthesized BCNO nanosheets as cold cathode materials have been studied for the first time in the high vacuum electron field emission set up. It has been seen that the material gives considerable field emission current with turn on field as low as 2.95 V/μm with good stability and thus a new cold cathode material can be postulated.

Using a Cold Radiometer to Measure Heat Loads and Survey Heat Leaks

NASA Technical Reports Server (NTRS)

Dipirro, M.; Tuttle, J.; Hait, T.; Shirron, P.

2014-01-01

We have developed an inexpensive cold radiometer for use in thermal/vacuum chambers to measure heat loads, characterize emissivity and specularity of surfaces and to survey areas to evaluate stray heat loads. We report here the results of two such tests for the James Webb Space Telescope to measure heat loads and effective emissivities of 2 major pieces of optical ground support equipment that will be used in upcoming thermal vacuum testing of the Telescope.

Using a Cold Radiometer to Measure Heat Loads and Survey Heat Leaks

NASA Technical Reports Server (NTRS)

DiPirro, M.; Tuttle, J.; Hait, T.; Shirron, P.

2013-01-01

We have developed an inexpensive cold radiometer for use in thermal/vacuum chambers to measure heat loads, characterize emissivity and specularity of surfaces and to survey areas to evaluate stray heat loads. We report here the results of two such tests for the James Webb Space Telescope to measure heat loads and effective emissivities of2 major pieces of optical ground support equipment that will be used in upcoming thermal vacuum testing of the Telescope.

Exhaust Emission Rates for Heavy-Duty On road Vehicles in MOVES201X

EPA Science Inventory

Updated running exhaust gaseous emission rates (THC, CO, NOx, CO2) for heavy-duty diesel trucks model year 2010 and later based on portable emission measurements from the manufacturer-run, heavy-duty in-use testing (HDIUT) program. Updated cold start emission rates and soak adjus...

Load-Dependent Emission Factors and Chemical Characteristics of IVOCs from a Medium-Duty Diesel Engine.

PubMed

Cross, Eben S; Sappok, Alexander G; Wong, Victor W; Kroll, Jesse H

2015-11-17

A detailed understanding of the climate and air quality impacts of mobile-source emissions requires the characterization of intermediate-volatility organic compounds (IVOCs), relatively-low-vapor-pressure gas-phase species that may generate secondary organic aerosol with high yields. Due to challenges associated with IVOC detection and quantification, IVOC emissions remain poorly understood at present. Here, we describe measurements of the magnitude and composition of IVOC emissions from a medium-duty diesel engine. Measurements are made on an engine dynamometer and utilize a new mass-spectrometric instrument to characterize the load dependence of the emissions in near-real-time. Results from steady-state engine operation indicate that IVOC emissions are highly dependent on engine power, with highest emissions at engine idle and low-load operation (≤25% maximum rated power) with a chemical composition dominated by saturated hydrocarbon species. Results suggest that unburned fuel components are the dominant IVOCs emitted at low loads. As engine load increases, IVOC emissions decline rapidly and become increasingly characterized by unsaturated hydrocarbons and oxygenated organics, newly formed from incomplete combustion processes at elevated engine temperatures and pressures. Engine transients, including a cold-start ignition and engine acceleration, show IVOC emission profiles that are different in amount or composition compared to steady-state combustion, underscoring the utility of characterizing IVOC emissions with high time resolution across realistic engine operating conditions. We find possible evidence for IVOC losses on unheated dilution and sampling surfaces, which need to be carefully accounted for in IVOC emission studies.

The 617 MHz-λ 850 μm correlation (cosmic rays and cold dust) in NGC 3044 and NGC 4157

NASA Astrophysics Data System (ADS)

Irwin, J. A.; Brar, R. S.; Saikia, D. J.; Henriksen, R. N.

2013-08-01

We present the first maps of NGC 3044 and NGC 4157 at λ 450 μm and λ 850 μm from the James Clerk Maxwell Telescope as well as the first maps at 617 MHz from the Giant Metrewave Radio Telescope. High-latitude emission has been detected in both the radio continuum and sub-mm for NGC 3044 and in the radio continuum for NGC 4157, including several new features. For NGC 3044, in addition, we find 617 MHz emission extending to the north of the major axis, beginning at the far ends of the major axis. One of these low-intensity features, more than 10 kpc from the major axis, has apparently associated emission at λ 20 cm and may be a result of in-disc activity related to star formation. The dust spectrum at long wavelengths required fitting with a two-temperature model for both galaxies, implying the presence of cold dust (Tc = 9.5 K for NGC 3044 and Tc = 15.3 K for NGC 4157). Dust masses are Md = 1.6 × 108 M⊙ and Md = 2.1 × 107 M⊙ for NGC 3044 and NGC 4157, respectively, and are dominated by the cold component. There is a clear correlation between the 617 MHz and λ 850 μm emission in the two galaxies. In the case of NGC 3044 for which the λ 850 μm data are strongly dominated by cold dust, this implies a relation between the non-thermal synchrotron emission and cold dust. The 617 MHz component represents an integration of massive star formation over the past 107-8 yr and the λ 850 μm emission represents heating from the diffuse interstellar radiation field (ISRF). The 617 MHz-λ 850 μm correlation improves when a smoothing kernel is applied to the λ 850 μm data to account for differences between the cosmic ray (CR) electron diffusion scale and the mean free path of an ISRF photon to dust. The best-fitting relation is L_{617_MHz} ∝ {L_{850μ m}}^{2.1 ± 0.2} for NGC 3044. If variations in the cold dust emissivity are dominated by variations in dust density, and the synchrotron emission depends on magnetic field strength (a function of gas density) as well as CR electron generation (a function of massive star formation rate and therefore density via the Schmidt law) then the expected correlation for NGC 3044 is L_{617_MHz} ∝ {L_{850μ m}}^{2.2}, in agreement with the observed correlation.

Effects of regional temperature on electric vehicle efficiency, range, and emissions in the United States.

PubMed

Yuksel, Tugce; Michalek, Jeremy J

2015-03-17

We characterize the effect of regional temperature differences on battery electric vehicle (BEV) efficiency, range, and use-phase power plant CO2 emissions in the U.S. The efficiency of a BEV varies with ambient temperature due to battery efficiency and cabin climate control. We find that annual energy consumption of BEVs can increase by an average of 15% in the Upper Midwest or in the Southwest compared to the Pacific Coast due to temperature differences. Greenhouse gas (GHG) emissions from BEVs vary primarily with marginal regional grid mix, which has three times the GHG intensity in the Upper Midwest as on the Pacific Coast. However, even within a grid region, BEV emissions vary by up to 22% due to spatial and temporal ambient temperature variation and its implications for vehicle efficiency and charging duration and timing. Cold climate regions also encounter days with substantial reduction in EV range: the average range of a Nissan Leaf on the coldest day of the year drops from 70 miles on the Pacific Coast to less than 45 miles in the Upper Midwest. These regional differences are large enough to affect adoption patterns and energy and environmental implications of BEVs relative to alternatives.

Chlorophyll fluorescence emission as a reporter on cold tolerance in Arabidopsis thaliana accessions

PubMed Central

Mishra, Anamika; Höermiller, Imke I; Heyer, Arnd G; Nedbal, Ladislav

2011-01-01

Non-invasive, high-throughput screening methods are valuable tools in breeding for abiotic stress tolerance in plants. Optical signals such as chlorophyll fluorescence emission can be instrumental in developing new screening techniques. In order to examine the potential of chlorophyll fluorescence to reveal plant tolerance to low temperatures, we used a collection of nine Arabidopsis thaliana accessions and compared their fluorescence features with cold tolerance quantified by the well established electrolyte leakage method on detached leaves. We found that, during progressive cooling, the minimal chlorophyll fluorescence emission rose strongly and that this rise was highly dependent on the cold tolerance of the accessions. Maximum quantum yield of PSII photochemistry and steady state fluorescence normalized to minimal fluorescence were also highly correlated to the cold tolerance measured by the electrolyte leakage method. In order to further increase the capacity of the fluorescence detection to reveal the low temperature tolerance, we applied combinatorial imaging that employs plant classification based on multiple fluorescence features. We found that this method, by including the resolving power of several fluorescence features, can be well employed to detect cold tolerance already at mild sub-zero temperatures. Therefore, there is no need to freeze the screened plants to the largely damaging temperatures of around −15°C. This, together with the method's easy applicability, represents a major advantage of the fluorescence technique over the conventional electrolyte leakage method. PMID:21427532

Thermophysical Properties of Cold and Vacuum Plasma Sprayed Cu-Cr-X Alloys, NiAl and NiCrAlY Coatings. Part 1; Electrical and Thermal Conductivity, Thermal Diffusivity, and Total Hemispherical Emissivity

NASA Technical Reports Server (NTRS)

Raj, S. V.

2017-01-01

This two-part paper reports the thermophysical properties of several cold and vacuum plasma sprayed monolithic Cu and Ni-based alloy coatings. Part I presents the electrical and thermal conductivity, thermal diffusivity, and total hemispherical emissivity data while Part II reports the specific heat capacity data for these coatings. Metallic copper alloys, stoichiometric NiAl and NiCrAlY coatings were fabricated by either the cold sprayed or the vacuum plasma spray deposition processes for thermal property measurements between 77 and 1223 K. The temperature dependencies of the thermal conductivities, thermal diffusivities, electrical conductivities and total hemispherical emissivities of these cold and vacuum sprayed monolithic coatings are reported in this paper. The electrical and thermal conductivity data correlate reasonably well for Cu-8%Cr-1%Al, Cu-23%Cr-5%Al and NiAl in accordance with the Wiedemann-Franz (WF) law although a better fit is obtained using the Smith-Palmer relationship. The Lorentz numbers determined from the WF law are close to the theoretical value.

[Fluorescence spectra analysis of the scrophularia soup].

PubMed

Yan, Li-hua; Song, Feng; Han, Juan; Su, Jing; Qu, Fei-fei; Song, Yi-zhan; Hu, Bo-lin; Tian, Jian-guo

2008-08-01

The cold-water and boiled-water soaked scrophularia soups have been prepared. The emission and excitation spectra of each scrophularia soup under different conditions have been measured at room temperature. The pH values of the different scrophularia soups have been also detected. There are obvious differences between the cold-water soaked scrophularia soup and the boiled-water soaked scrophularia. For both soups the emission wavelength increases with the wavelength of the excitation, but the peaks of the emission spectra for cold-water and boiled-water soaked scrophularia soup are different, which are 441 and 532 nm, respectively. Excitation spectrum has double peaks in the cold-water soaked scrophularia soup while only one peak with longer wavelength in the boiled-water soaked one. The pH value changes from 5.5 to 4.1. According to the organic admixture fluorescence mechanism we analyzed the reasons of the experimental results. Through heating, the interaction in different fluorescence molecular and the energy transfer process in the same fluorescence molecular become more active, and the conjugate structures and the generation of hydrogen bonds, increase. The fluorescence measurement is of value for the scrophularia pharmacology analysis and provides an analytical method for the quality identification of scrophularia soup.

Thermophysical Properties of Cold- and Vacuum Plasma-Sprayed Cu-Cr-X Alloys, NiAl and NiCrAlY Coatings I: Electrical and Thermal Conductivity, Thermal Diffusivity, and Total Hemispherical Emissivity

NASA Astrophysics Data System (ADS)

Raj, S. V.

2017-11-01

This two-part paper reports the thermophysical properties of several cold- and vacuum plasma-sprayed monolithic Cu- and Ni-based alloy coatings. Part I presents the electrical and thermal conductivity, thermal diffusivity, and total hemispherical emissivity data, while Part II reports the specific heat capacity data for these coatings. Metallic copper alloys and stoichiometric NiAl and NiCrAlY coatings were fabricated by either the cold spray or the vacuum plasma spray deposition processes for thermal property measurements between 77 and 1223 K. The temperature dependencies of the thermal conductivities, thermal diffusivities, electrical conductivities, and total hemispherical emissivities of these cold- and vacuum-sprayed monolithic coatings are reported in this paper. The electrical and thermal conductivity data correlate reasonably well for Cu-8%Cr-1%Al, Cu-23%Cr-5%Al, and NiAl in accordance with the Wiedemann-Franz (WF) law although a better fit is obtained using the Smith-Palmer relationship. The Lorentz numbers determined from the WF law are close to the theoretical value.

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

Tierno, S. P., E-mail: sp.tierno@upm.es; Donoso, J. M.; Domenech-Garret, J. L.

The interaction between an electron emissive wall, electrically biased in a plasma, is revisited through a simple fluid model. We search for realistic conditions of the existence of a non-monotonic plasma potential profile with a virtual cathode as it is observed in several experiments. We mainly focus our attention on thermionic emission related to the operation of emissive probes for plasma diagnostics, although most conclusions also apply to other electron emission processes. An extended Bohm criterion is derived involving the ratio between the two different electron densities at the potential minimum and at the background plasma. The model allows amore » phase-diagram analysis, which confirms the existence of the non-monotonic potential profiles with a virtual cathode. This analysis shows that the formation of the potential well critically depends on the emitted electron current and on the velocity at the sheath edge of cold ions flowing from the bulk plasma. As a consequence, a threshold value of the governing parameter is required, in accordance to the physical nature of the electron emission process. The latter is a threshold wall temperature in the case of thermionic electrons. Experimental evidence supports our numerical calculations of this threshold temperature. Besides this, the potential well becomes deeper with increasing electron emission, retaining a fraction of the released current which limits the extent of the bulk plasma perturbation. This noninvasive property would explain the reliable measurements of plasma potential by using the floating potential method of emissive probes operating in the so-called strong emission regime.« less

The role of Hurst exponent on cold field electron emission from conducting materials: from electric field distribution to Fowler-Nordheim plots

PubMed Central

de Assis, T. A.

2015-01-01

This work considers the effects of the Hurst exponent (H) on the local electric field distribution and the slope of the Fowler-Nordheim (FN) plot when considering the cold field electron emission properties of rough Large-Area Conducting Field Emitter Surfaces (LACFESs). A LACFES is represented by a self-affine Weierstrass-Mandelbrot function in a given spatial direction. For 0.1 ≤ H < 0.5, the local electric field distribution exhibits two clear exponential regimes. Moreover, a scaling between the macroscopic current density () and the characteristic kernel current density (), , with an H-dependent exponent , has been found. This feature, which is less pronounced (but not absent) in the range where more smooth surfaces have been found (), is a consequence of the dependency between the area efficiency of emission of a LACFES and the macroscopic electric field, which is often neglected in the interpretation of cold field electron emission experiments. Considering the recent developments in orthodox field emission theory, we show that the exponent must be considered when calculating the slope characterization parameter (SCP) and thus provides a relevant method of more precisely extracting the characteristic field enhancement factor from the slope of the FN plot. PMID:26035290

Facile synthesis of ZnPc nanocubes: An electron emitting material for field emission display devices

NASA Astrophysics Data System (ADS)

Samanta, M.; Ghorai, U. K.; Mukherjee, M.; Howli, P.; Chattopadhyay, K. K.

2017-05-01

A simple low temperature water chemical route for synthesizing Zinc Phthalocyanine (ZnPc) nanostructures were reported here. The as-prepared samples were well analysed by X-ray diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM) technique. The plausible formation mechanism of cube like nanostructures was also explained here. Cold cathode emission properties of ZnPc nanocubes were studied by using an indigenously designed high vacuum system at anode to cathode distance 130 µm. The turn on field and enhancement factor is found to be 5.0 V/μm @ 1µA/cm2 and 1757 respectively. Cold cathode emission properties were further investigated theoretically by finite element method using ANSYS Maxwell simulation package. The obtained results strongly professed that ZnPc nanocubes can act as potential candidate for electron emitter for field emission display devices and many more.

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.

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...

Theoretical and Observational Studies of the Central Engines of AGN

NASA Technical Reports Server (NTRS)

Sivron, Ran

1995-01-01

In Active Galactic Nuclei (AGN) the luminosity is so intense that the effect of radiation pressure on a particle may exceed the gravitational attraction. It was shown that when such luminosities are reached, relatively cold (not completely ionized) thermal matter clouds may form in the central engines of AGN, where most of the luminosity originates. We show that the spectrum of emission from cold clouds embedded in hot relativistic matter is similar to the observed spectrum. We also show that within the hot relativistic matter, cold matter moves faster than the speed of sound or the Alfven speed, and shocks form. The shocks provide a mechanism by which a localized perturbation can propagate throughout the central engine. The shocked matter can emit the observed luminosity, and can explain the flux and spectral variability. It may also provide an efficient mechanism for the outward transfer of angular momentum and provide the outward flow of winds. With observations from X-ray satellites, emission features from the cold and hot matter may be revealed. Our analysis of X-ray data from the Seyfert 1 galaxy MCG - 6-30-15 over five years using detectors on the Ginga and Rosat satellites, revealed some interesting variable features. A source with hot matter emits non-thermal radiation which is Compton reflected from cold matter and then absorbed by warm (partially ionized) absorbing matter in the first model, which can be fit to the data if both the cold and warm absorbers are near the central engine. An alternative model in which the emission from the hot matter is partially covered by very warm matter (in which all elements except Iron are mostly ionized) is also successful. In this model the cold and warm matter may be at distances of up to 100 times the size of the central engine, well within the region where broad optical lines are produced. The flux variability is more naturally explained by the second model. Our results support the existence of cold matter in, or near, the central engine of MCG -6-30-15. Cold matter in the central engine, and evidence of the effects of shocks, is probably forthcoming with future X-ray satellites.

Aberration corrected 1.2-MV cold field-emission transmission electron microscope with a sub-50-pm resolution

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

Akashi, Tetsuya; Takahashi, Yoshio; Tanigaki, Toshiaki, E-mail: toshiaki.tanigaki.mv@hitachi.com

2015-02-16

Atomic-resolution electromagnetic field observation is critical to the development of advanced materials and to the unveiling of their fundamental physics. For this purpose, a spherical-aberration corrected 1.2-MV cold field-emission transmission electron microscope has been developed. The microscope has the following superior properties: stabilized accelerating voltage, minimized electrical and mechanical fluctuation, and coherent electron emission. These properties have enabled to obtain 43-pm information transfer. On the bases of these performances, a 43-pm resolution has been obtained by correcting lens aberrations up to the third order. Observations of GaN [411] thin crystal showed a projected atomic locations with a separation of 44 pm.

Temporal dynamics of direct N2O fluxes from agro-ecosystems in cold climates: importance of year-round measurements in multiple cropping systems

NASA Astrophysics Data System (ADS)

Wagner-Riddle, C.; Tenuta, M.

2014-12-01

Soil N2O fluxes (direct emissions) are highly variable in time and space due to soil, weather and management drivers. In cold climates, freeze/thaw cycles and short growing seasons can enhance soil N2O production contributing to the temporal variability of fluxes. Year-round measurements of N2O fluxes in multiple cropping systems are needed to decrease the uncertainty of annual emission estimates and to devise mitigation practices for emission reduction in cold climates. We have deployed a micrometeorological flux-gradient approach coupled to a tunable diode laser absorption spectroscopy system at two long-term sites in Canada: Elora, Ontario (2000-2014) and Glenlea, Manitoba (2006-2014). Quasi-simultaneous half-hourly flux measurements on four 4-ha fields within a level and aerodynamically homogeneous landscape were obtained allowing for comparison of crop type and/or management practices within and between years. Annual crops such as corn, soybeans, wheat, and barley received typical inorganic fertilizer and/or manure applications, and best management practices such as timing of application and reduced tillage were studied. Perennial grass-alfalfa hayfields were compared to annual crops during selected time periods. Here we synthesize the long-term datasets from these two sites, and quantify the overall contribution of non-growing season (mainly freeze/thaw cycles) and growing season (mainly nitrogen application) to annual emission totals. Uncertainties of regional estimates for cold-climates will be assessed using these long-term datasets.

Constraining East Asian CO2 emissions with GOSAT retrievals: methods and policy implications

NASA Astrophysics Data System (ADS)

Shim, C.; Henze, D. K.; Deng, F.

2017-12-01

The world largest CO2 emissions are from East Asia. However, there are large uncertainties in CO2 emission inventories, mainly because of imperfections in bottom-up statistics and a lack of observations for validating emission fluxes, particularly over China. Here we tried to constrain East Asian CO2 emissions with GOSAT retrievals applying 4-Dvar GEOS-Chem and its adjoint model. We applied the inversion to only the cold season (November - February) in 2009 - 2010 since the summer monsoon and greater transboundary impacts in spring and fall greatly reduced the GOSAT retrievals. In the cold season, the a posteriori CO2 emissions over East Asia generally higher by 5 - 20%, particularly Northeastern China shows intensively higher in a posteriori emissions ( 20%), where the Chinese government is recently focusing on mitigating the air pollutants. In another hand, a posteriori emissions from Southern China are lower 10 - 25%. A posteriori emissions in Korea and Japan are mostly higher by 10 % except over Kyushu region. With our top-down estimates with 4-Dvar CO2 inversion, we will evaluate the current regional CO2 emissions inventories and potential uncertainties in the sectoral emissions. This study will help understand the quantitative information on anthropogenic CO2 emissions over East Asia and will give policy implications for the mitigation targets.

Effect of cold rolling on the microstructural evolution of new β-typed Ti–6Mo–6V–5Cr–3Sn–2.5Zr alloys

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

Choi, Gwnaghyo; Lee, Kwangmin, E-mail: kmlee@jnu.a

A Ti–6Mo–6V–5Cr–3Sn–2.5Zr (wt.%) alloy was designed as a new metastable β-Ti alloy. The effect that cold rolling had on the microstructural evolution of the material was investigated via optical microscopy (OM), X-ray diffraction (XRD), electron back-scattered diffraction (EBSD) and transmission electron microscopy (TEM) measurements. A single β phase formed in the alloy after solution treatment at 780 °C for 30 min followed by water quenching. The solution-treated alloy was cold rolled with thickness reductions of 10%, 30%, 50% and 70%, and the hardness values increased as the thickness of the specimen decreased. The textures of the cold rolled specimen weremore » characterized according to the 〈110〉 partial parallel to the rolling direction as the rolling reduction increased. The crystallographic orientation showed principal α-fiber textures for (111)〈110〉 and (112)〈110〉. The cold deformation led to the appearance of martensite α″ phases, particularly stress-induced martensite (SIM) α″ phases. - Highlights: • Effect of cold rolling on new β-typed Ti-6Mo-6V-5Cr-3Sn-2.5Zr alloy was studied. • A single β phase was obtained after solution treatment at 780 °C for 30 min. • α-Fiber textures became dominated with the increase in cold rolling reduction. • A stress-induced α″ martensite was caused by cold rolling.« less

Comprehensive particle characterization of modern gasoline and diesel passenger cars at low ambient temperatures

NASA Astrophysics Data System (ADS)

Mathis, Urs; Mohr, Martin; Forss, Anna-Maria

Particle measurements were performed in the exhaust of five light-duty vehicles (Euro-3) at +23, -7, and -20 °C ambient temperatures. The characterization included measurements of particle number, active surface area, number size distribution, and mass size distribution. We investigated two port-injection spark-ignition (PISI) vehicles, a direct-injection spark-ignition (DISI) vehicle, a compressed ignition (CI) vehicle with diesel particle filter (DPF), and a CI vehicle without DPF. To minimize sampling effects, particles were directly sampled from the tailpipe with a novel porous tube diluter at controlled sampling parameters. The diluted exhaust was split into two branches to measure either all or only non-volatile particles. Effect of ambient temperature was investigated on particle emission for cold and warmed-up engine. For the gasoline vehicles and the CI vehicle with DPF, the main portion of particle emission was found in the first minutes of the driving cycle at cold engine start. The particle emission of the CI vehicle without DPF was hardly affected by cold engine start. For the PISI vehicles, particle number emissions were superproportionally increased in the diameter size range from 0.1 to 0.3 μm during cold start at low ambient temperature. Based on the particle mass size distribution, the DPF removed smaller particles ( dp<0.5μm) more efficiently than larger particles ( dp>0.5μm). No significant effect of ambient temperature was observed when the engine was warmed up. Peak emission of volatile nanoparticles only took place at specific conditions and was poorly repeatable. Nucleation of particles was predominately observed during or after strong acceleration at high speed and during regeneration of the DPF.

Systems and methods to mitigate NO.sub.x and HC emissions

DOEpatents

Gupta, Aniket; Cunningham, Michael J.; Ruth, Michael J.; Chilumukuru, Krishna P.

2017-06-14

Systems and methods are provided for managing low temperature NO.sub.x and HC emissions, such as during a cold start of an internal combustion engine. The systems and methods include storing NO.sub.x and HC emissions at low temperatures and passively releasing and treating these emissions as the temperature of the exhaust system increases.

Current and future hot-spots and hot-moments of nitrous oxide emission in a cold climate river basin.

PubMed

Shrestha, Narayan Kumar; Wang, Junye

2018-08-01

An ecosystem in a cold climate river basin is vulnerable to the effects of climate change affecting permafrost thaw and glacier retreat. We currently lack sufficient data and information if and how hydrological processes such as glacier retreat, snowmelt and freezing-thawing affect sediment and nutrient runoff and transport, as well as N 2 O emissions in cold climate river basins. As such, we have implemented well-established, semi-empirical equations of nitrification and denitrification within the Soil and Water Assessment Tool (SWAT), which correlate the emissions with water, sediment and nutrients. We have tested this implementation to simulate emission dynamics at three sites on the Canadian prairies. We then regionalized the optimized parameters to a SWAT model of the Athabasca River Basin (ARB), Canada, calibrated and validated for streamflow, sediment and water quality. In the base period (1990-2005), agricultural areas (2662 gN/ha/yr) constituted emission hot-spots. The spring season in agricultural areas and summer season in forest areas, constituted emission hot-moments. We found that warmer conditions (+13% to +106%) would have a greater influence on emissions than wetter conditions (-19% to +13%), and that the combined effect of wetter and warmer conditions would be more offsetting than synergetic. Our results imply that the spatiotemporal variability of N 2 O emissions will depend strongly on soil water changes caused by permafrost thaw. Early snow freshet leads to spatial variability of soil erosion and nutrient runoff, as well as increases of emissions in winter and decreases in spring. Our simulations suggest crop residue management may reduce emissions by 34%, but with the mixed results reported in the literature and the soil and hydrology problems associated with stover removal more research is necessary. This modelling tool can be used to refine bottom-up emission estimations at river basin scale, test plausible management scenarios, and assess climate change impacts including climate feedback. Copyright © 2018 Elsevier Ltd. All rights reserved.

Limited Range Sesame EOS for Ta

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

Greeff, Carl William; Crockett, Scott; Rudin, Sven Peter

2017-03-30

A new Sesame EOS table for Ta has been released for testing. It is a limited range table covering T ≤ 26, 000 K and ρ ≤ 37.53 g/cc. The EOS is based on earlier analysis using DFT phonon calculations to infer the cold pressure from the Hugoniot. The cold curve has been extended into compression using new DFT calculations. The present EOS covers expansion into the gas phase. It is a multi-phase EOS with distinct liquid and solid phases. A cold shear modulus table (431) is included. This is based on an analytic interpolation of DFT calculations.

Dust silicate emission in FIR/submm

NASA Astrophysics Data System (ADS)

Coupeaud, A.; Demyk, K.; Mény, C.; Nayral, C.

2010-12-01

The far-infrared to millimeter wavelength (FIR-mm) range in astronomical observations is dominated by the thermal emission from large (10-100 nm) and cold (10-20 K) dust grains, which are in thermal equilibrium with the interstellar radiation field. However, the physics of the FIR-mm emission from such cold matter is not well understood as shown by the observed dependence with the temperature of the spectral index of the dust emissivity β and by the observed far infrared excess. Interestingly, a similar behaviour is observed in experiments of characterization of the spectral properties of dust analogues. We present a study of the optical properties of analogues of interstellar silicate grains at low temperature in the FIR/submm range aiming to understand their peculiar behaviour. Such studies are essential for the interpretation of the Herschel and Planck data.

Stratified NH and ND emission in the prestellar core 16293E in L1689N

NASA Astrophysics Data System (ADS)

Bacmann, A.; Daniel, F.; Caselli, P.; Ceccarelli, C.; Lis, D.; Vastel, C.; Dumouchel, F.; Lique, F.; Caux, E.

2016-03-01

Context. High degrees of deuterium fractionation are commonly found in cold prestellar cores and in the envelopes around young protostars. As it brings strong constraints to chemical models, deuterium chemistry is often used to infer core history or molecule formation pathways. Whereas a large number of observations are available regarding interstellar deuterated stable molecules, relatively little is known about the deuteration of hydride radicals, as their fundamental rotational transitions are at high frequencies where the atmosphere is mostly opaque. Aims: Nitrogen hydride radicals are important species in nitrogen chemistry, as they are thought to be related to ammonia formation. Observations have shown that ammonia is strongly deuterated, with [NH2D]/[NH3] ~ 10%. Models predict similarly high [ND]/[NH] ratios, but so far only one observational determination of this ratio is available, towards the envelope of the protostar IRAS16293-2422. To test model predictions, we aim here to determine [ND]/[NH] in a dense, starless core. Methods: We observed NH and ND in 16293E with the HIFI spectrometer on board the Herschel Space Observatory as part of the CHESS guaranteed time key programme, and derived the abundances of these two species using a non local thermodynamic equilibrium radiative transfer model. Results: Both NH and ND are detected in the source, with ND in emission and NH in absorption against the continuum that arises from the cold dust emission. Our model shows, however, that the ND emission and the NH absorption originate from different layers in the cloud, as further evidenced by their different velocities. In the central region of the core, we can set a lower limit to the [ND]/[NH] ratio of ≳2%. This estimate is consistent with recent pure gas-phase models of nitrogen chemistry. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

Transport pathways for Asian pollution outflow over the Pacific: Interannual and seasonal variations

NASA Astrophysics Data System (ADS)

Liu, Hongyu; Jacob, Daniel J.; Bey, Isabelle; Yantosca, Robert M.; Duncan, Bryan N.; Sachse, Glen W.

2003-10-01

The meteorological pathways contributing to Asian pollution outflow over the Pacific are examined with a global three-dimensional model analysis of CO observations from the Transport and Chemical Evolution over the Pacific (TRACE-P) aircraft mission (February-April 2001). The model is used also to place the TRACE-P observations in an interannual (1994-2001) and seasonal context. The major process driving Asian pollution outflow in spring is frontal lifting ahead of southeastward-moving cold fronts (the leading edge of cold surges) and transport in the boundary layer behind the cold fronts. Orographic lifting over central and eastern China combines with the cold fronts to promote the transport of Chinese pollution to the free troposphere. Outflow of seasonal biomass burning in Southeast Asia during spring takes place mostly by deep convection but also by northeastward transport and frontal lifting, mixing with the anthropogenic outflow. Boundary layer outflow over the western Pacific is largely devoid of biomass burning influence. European and African (biomass burning) plumes in Asian outflow during TRACE-P were weak (<60 ppbv and 20 ppbv CO, respectively) and were not detectable in the observations because of superposition of the much larger Asian pollution signal. Spring 2001 (La Niña) was characterized by unusually frequent cold surge events in the Asian Pacific rim and strong convection in Southeast Asia, leading to unusually strong boundary layer outflow of anthropogenic emissions and convective outflow of biomass burning emissions in the upper troposphere. The Asian outflow flux of CO to the Pacific is found to vary seasonally by a factor of 3-4 (maximum in March and minimum in summer). The March maximum results from frequent cold surge events and seasonal biomass burning emissions.

Transport Pathways for Asian Pollution Outflow Over the Pacific: Interannual and Seasonal Variations

NASA Technical Reports Server (NTRS)

Liu, Hong-Yu; Jacob, Daniel J.; Bey, Isabelle; Yantosca, Robert M.; Duncan, Bryan N.; Sachse, Glen W.

2003-01-01

The meteorological pathways contributing to Asian pollution outflow over the Pacific are examined with a global three-dimensional model analysis of CO observations from the Transport and Chemical Evolution over the Pacific (TRACE-P) aircraft mission (February-April 2001). The model is used also to place the TRACE-P observations in an interannual (1994-2001) and seasonal context. The major process driving Asian pollution outflow in spring is frontal lifting ahead of southeastward-moving cold fronts (the leading edge of cold surges) and transport in the boundary layer behind the cold fronts. Orographic lifting over central and eastern China combines with the cold fronts to promote the transport of Chinese pollution to the free troposphere. Outflow of seasonal biomass burning in Southeast Asia during spring takes place mostly by deep convection but also by northeastward transport and frontal lifting, mixing with the anthropogenic outflow. Boundary layer outflow over the western Pacific is largely devoid of biomass burning influence. European and African (biomass burning) plumes in Asian outflow during TRACE-P were weak (less than 60 ppbv and 20 ppbv CO, respectively) and were not detectable in the observations because of superposition of the much larger Asian pollution signal. Spring 2001 (La Nina) was characterized by unusually frequent cold surge events in the Asian Pacific rim and strong convection in Southeast Asia, leading to unusually strong boundary layer outflow of anthropogenic emissions and convective outflow of biomass burning emissions in the upper troposphere. The Asian outflow flux of CO to the Pacific is found to vary seasonally by a factor of 3-4 (maximum in March and minimum in summer). The March maximum results from frequent cold surge events and seasonal biomass burning emissions.

40 CFR 86.237-94 - Dynamometer test run, gaseous emissions.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.237-94 Dynamometer...

40 CFR 86.244-94 - Calculations; exhaust emissions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.244-94 Calculations; exhaust...

A Fully-Sealed Carbon-Nanotube Cold-Cathode Terahertz Gyrotron

PubMed Central

Yuan, Xuesong; Zhu, Weiwei; Zhang, Yu; Xu, Ningsheng; Yan, Yang; Wu, Jianqiang; Shen, Yan; Chen, Jun; She, Juncong; Deng, Shaozhi

2016-01-01

Gigahertz to terahertz radiation sources based on cold-cathode vacuum electron technology are pursued, because its unique characteristics of instant switch-on and power saving are important to military and space applications. Gigahertz gyrotron was reported using carbon nanotube (CNT) cold-cathode. It is reported here in first time that a fully-sealed CNT cold-cathode 0.22 THz-gyrotron is realized, typically with output power of 500 mW. To achieve this, we have studied mechanisms responsible for CNTs growth on curved shape metal surface, field emission from the sidewall of a CNT, and crystallized interface junction between CNT and substrate material. We have obtained uniform growth of CNTs on and direct growth from cone-cylinder stainless-steel electrode surface, and field emission from both tips and sidewalls of CNTs. It is essential for the success of a CNT terahertz gyrotron to have such high quality, high emitting performance CNTs. Also, we have developed a magnetic injection electron gun using CNT cold-cathode to exploit the advantages of such a conventional gun design, so that a large area emitting surface is utilized to deliver large current for electron beam. The results indicate that higher output power and higher radiation frequency terahertz gyrotron may be made using CNT cold-cathode electron gun. PMID:27609247

A Fully-Sealed Carbon-Nanotube Cold-Cathode Terahertz Gyrotron.

PubMed

Yuan, Xuesong; Zhu, Weiwei; Zhang, Yu; Xu, Ningsheng; Yan, Yang; Wu, Jianqiang; Shen, Yan; Chen, Jun; She, Juncong; Deng, Shaozhi

2016-09-09

Gigahertz to terahertz radiation sources based on cold-cathode vacuum electron technology are pursued, because its unique characteristics of instant switch-on and power saving are important to military and space applications. Gigahertz gyrotron was reported using carbon nanotube (CNT) cold-cathode. It is reported here in first time that a fully-sealed CNT cold-cathode 0.22 THz-gyrotron is realized, typically with output power of 500 mW. To achieve this, we have studied mechanisms responsible for CNTs growth on curved shape metal surface, field emission from the sidewall of a CNT, and crystallized interface junction between CNT and substrate material. We have obtained uniform growth of CNTs on and direct growth from cone-cylinder stainless-steel electrode surface, and field emission from both tips and sidewalls of CNTs. It is essential for the success of a CNT terahertz gyrotron to have such high quality, high emitting performance CNTs. Also, we have developed a magnetic injection electron gun using CNT cold-cathode to exploit the advantages of such a conventional gun design, so that a large area emitting surface is utilized to deliver large current for electron beam. The results indicate that higher output power and higher radiation frequency terahertz gyrotron may be made using CNT cold-cathode electron gun.

Chemical Weathering on a Cold and Wet Ancient Mars: New Insights from a Glacial Mars Analog Site

NASA Astrophysics Data System (ADS)

Scudder, N.; Horgan, B. H. N.; Rutledge, A. M.; Rampe, E. B.

2016-12-01

If cold climates prevailed on ancient Mars, we should expect to see corroborating mineralogical evidence preserved in the geologic record. However, the extent to which the diverse alteration mineralogy observed on Mars can be explained by cold climate weathering is currently unknown, as the alteration phases that result from weathering by snow and ice are poorly understood. If cold climate weathering produces distinct alteration signatures, they may be a useful climate indicator on Mars. On Earth, poorly crystalline or short order silicates, such as allophane, tend to dominate in alpine and arctic soils where weathering mainly occurs through rapid seasonal melting of ice and snow. This mineralogy is distinct from the crystalline phyllosilicates that are common in more temperate climates. Thus, we hypothesize that high abundances of poorly crystalline material could indicate cold climate weathering. Here we report new results from a field campaign at the mafic and glaciated Three Sisters volcanic complex in Oregon, USA, to determine the mineralogy and chemistry of cold climate weathering in a Mars analog environment. We find that high abundances of poorly crystalline phases are generated in this environment and that these phases may be detectable using orbital spectroscopy. Ongoing chemical and mineralogical analyses of glacial till and sediments from glacier-fed lakes and streams will allow us to determine the specific distribution and composition of mineral phases in Mars-relevant glacial environments. Poorly crystalline phases have been detected on Mars: modeling of TES data suggests a regionally distributed allophane component, while MER and MSL results indicate up to 40-50% amorphous components in rocks and sediments at Gusev and Gale Craters. We hypothesize that these could be the result of weathering by ice and snow. However, it is not clear that more crystalline alteration phases observed elsewhere on Mars could be formed under a globally cold climate.

Pulsed Discharge Nozzle Cavity Ring Down Spectroscopy of Cold PAH Ions

NASA Technical Reports Server (NTRS)

Biennier, Ludovic; Salama, Farid; Allamandola, Louis J.; Scherer, James J.; DeVincenzi, Donald (Technical Monitor)

2002-01-01

The gas-phase electronic absorption spectra of the naphthalene (C10H8(+)) and acenaphthene (C12H10(+)) cations have been measured in the visible range in a free 10 jet planar expansion in an attempt to collect data in an astrophysically relevant environment. The direct absorption spectra of two out of four bands measured of the gas-phase cold naphthalene cation along with the gas-phase vibronic absorption spectrum of the cold acenaphthene cation are reported for the first time. The study has been carried out using the ultrasensitive and versatile technique of cavity ringdown spectroscopy (CRDS) coupled to a pulsed discharge slit nozzle (PDN). The new CRDS-PDN set up is described and its characteristics are evaluated. The direct-absorption spectra of the PAH ions are discussed and compared to the gas-phase and solid-phase data available in the literature. The analysis of the results show that cold, free flying PAH ions are generated in the argon discharge primarily through soft Penning ionization. This enables the intrinsic band profiles to be measured, a key requirement for astrophysical applications.

Ambient Temperature, Fuel Economy, Emissions, and Trip Length

DOT National Transportation Integrated Search

1979-08-01

This report examines the relationship among automotive fuel economy, ambient temperature, cold-start trip length, and drive-train component temperatures of four 1977 vehicles. Fuel economy, exhaust emission, and drive-train temperatures were measured...

Lagrangian Hotspots of In-Use NOX Emissions from Transit Buses.

PubMed

Kotz, Andrew J; Kittelson, David B; Northrop, William F

2016-06-07

In-use, spatiotemporal NOX emissions were measured from a conventional powertrain transit bus and a series electric hybrid bus over gradients of route kinetic intensity and ambient temperature. This paper introduces a new method for identifying NOX emissions hotspots along a bus route using high fidelity Lagrangian vehicle data to explore spatial interactions that may influence emissions production. Our study shows that the studied transit buses emit higher than regulated emissions because on-route operation does not accurately represent the range of engine operation tested according to regulatory standards. Using the Lagrangian hotspot detection, we demonstrate that NOX hotspots occurred at bus stops, during cold starts, on inclines, and for accelerations. On the selected routes, bus stops resulted in 3.3 times the route averaged emissions factor in grams/km without significant dependence on bus type or climate. The buses also emitted 2.3 times the route averaged NOX emissions factor at the beginning of each route due to cold selective catalytic reduction aftertreatment temperature. The Lagrangian hotspot detection technique demonstrated here could be employed in future connected vehicles empowered by advances in computational power, data storage capability, and improved sensor technology to optimize emissions as a function of spatial location.

November 15, 1991 X Flare -- The Movie: Hα , Soft X-rays, and Hard X-rays and Magnetic Fields

NASA Astrophysics Data System (ADS)

Wulser, J.-P.; Acton, L.; Sakao, T.; Canfield, R.; Kosugi, T.; Slater, G.; Strong, K.; Tsuneta, S.

1992-05-01

The X1.5/3B flare on 1991 November 15, 22:33 UT was well observed by the Hα Imaging Spectrograph and the Vector Magnetograph (Stokes Polarimeter) at Mees Solar Observatory, and by the Soft- and Hard X-ray Telescopes (SXT and HXT) aboard YOHKOH. We have combined this multispectral dataset into a series of temporally and spatially co-aligned video movies and analyzed the morphological and temporal relationships of the various flare emissions. The earliest manifestations of this flare include unresolved preflare SXR brightenings very close to the magnetic neutral line and preflare motions of filaments seen in Hα . In the flare core, SXR and Hα emission show moving and rotating coronal structures which we interpret as a successive brightening of adjacent loops during the main phase of the flare. The HXR source shows much more dramatic variability than the SXR source, and they are clearly not cospatial. On the other hand, there is a close spatial relationship between the HXR and Hα blue wing emission sites. The Hα , HXR, and SXR images all point to acceleration and heating in a region that starts close to the neutral line and moves outward during each HXR burst and during the gradual phase. Spectacular mass ejections are seen in both SXR and Hα , with clear unwinding of tightly coiled structures, acceleration of X-ray and Hα material to velocities of order 1000 km/s, and a striking thermal bifurcation between hot and cold plasma.

Multi-phase Nature of a Radiation-driven Fountain with Nuclear Starburst in a Low-mass Active Galactic Nucleus

NASA Astrophysics Data System (ADS)

Wada, Keiichi; Schartmann, Marc; Meijerink, Rowin

2016-09-01

The structures and dynamics of molecular, atomic, and ionized gases are studied around a low-luminosity active galactic nucleus (AGN) with a small (2× {10}6{M}⊙ ) black hole using three-dimensional (3D) radiation-hydrodynamic simulations. We studied, for the first time, the non-equilibrium chemistry for the X-ray-dominated region in the “radiation-driven fountain” with supernova feedback. A double hollow cone structure is naturally formed without postulating a thick “torus” around a central source. The cone is occupied with an inhomogeneous, diffuse ionized gas and surrounded by a geometrically thick (h/r≳ 1) atomic gas. Dense molecular gases are distributed near the equatorial plane, and energy feedback from supernovae enhances their scale height. Molecular hydrogen exists in a hot phase (>1000 K) as well as in a cold (\\lt 100 {{K}}), dense (\\gt {10}3 {{cm}}-3) phase. The velocity dispersion of H2 in the vertical direction is comparable to the rotational velocity, which is consistent with near-infrared observations of nearby Seyfert galaxies. Using 3D radiation transfer calculations for the dust emission, we find polar emission in the mid-infrared band (12 μm), which is associated with bipolar outflows, as suggested in recent interferometric observations of nearby AGNs. If the viewing angle for the nucleus is larger than 75°, the spectral energy distribution is consistent with that of the Circinus galaxy. The multi-phase interstellar medium observed in optical/infrared and X-ray observations is also discussed.

Optical properties of lamps with cold emission cathode

NASA Astrophysics Data System (ADS)

Kalenik, Jerzy; Czerwosz, ElŻbieta; Biernacki, Krzysztof; Rymarczyk, Joanna; Stepińska, Izabela

2016-12-01

A luminescent lamp was constructed and tested. Phosphor excited by electrons is the source of light. The source of electrons is field emission cathode. The cathode is covered with nickel-carbon layer containing carbon nanotubes that enhance electron emission from the cathode. Results of luminance measurements are presented. Luminance is high enough for lighting application.

Methane fluxes during the cold season: distribution and mass transfer in the snow cover of bogs

NASA Astrophysics Data System (ADS)

Smagin, A. V.; Shnyrev, N. A.

2015-08-01

Fluxes and profile distribution of methane in the snow cover and different landscape elements of an oligotrophic West-Siberian bog (Mukhrino Research Station, Khanty-Mansiisk autonomous district) have been studied during a cold season. Simple models have been proposed for the description of methane distribution in the inert snow layer, which combine the transport of the gas and a source of constant intensity on the soil surface. The formation rates of stationary methane profiles in the snow cover have been estimated (characteristic time of 24 h). Theoretical equations have been derived for the calculation of small emission fluxes from bogs to the atmosphere on the basis of the stationary profile distribution parameters, the snow porosity, and the effective methane diffusion coefficient in the snow layer. The calculated values of methane emission significantly (by 2-3 to several tens of times) have exceeded the values measured under field conditions by the closed chamber method (0.008-0.25 mg C/(m2 h)), which indicates the possibility of underestimating the contribution of the cold period to the annual emission cycle of bog methane.

Relationship between directions of wave and energy propagation for cold plasma waves

NASA Technical Reports Server (NTRS)

Musielak, Zdzislaw E.

1986-01-01

The dispersion relation for plasma waves is considered in the 'cold' plasma approximation. General formulas for the dependence of the phase and group velocities on the direction of wave propagation with respect to the local magnetic field are obtained for a cold magnetized plasma. The principal cold plasma resonances and cut-off frequencies are defined for an arbitrary angle and are used to establish basic regimes of frequency where the cold plasma waves can propagate or can be evanescent. The relationship between direction of wave and energy propagation, for cold plasma waves in hydrogen atmosphere, is presented in the form of angle diagrams (angle between group velocity and magnetic field versus angle between phase velocity and magnetic field) and polar diagrams (also referred to as 'Friedrich's diagrams') for different directions of wave propagation. Morphological features of the diagrams as well as some critical angles of propagation are discussed.

CO2 Condensation Models for Mars

NASA Technical Reports Server (NTRS)

Colaprete, A.; Haberle, R.

2004-01-01

During the polar night in both hemispheres of Mars, regions of low thermal emission, frequently referred to as "cold spots", have been observed by Mariner 9, Viking and Mars Global Surveyor (MGS) spacecraft. These cold spots vary in time and appear to be associated with topographic features suggesting that they are the result of a spectral-emission effect due to surface accumulation of fine-grained frost or snow. Presented here are simulations of the Martian polar night using the NASA Ames General Circulation Cloud Model. This cloud model incorporates all the microphysical processes of carbon dioxide cloud formation, including nucleation, condensation and sedimentation and is coupled to a surface frost scheme that includes both direct surface condensation and precipitation. Using this cloud model we simulate the Mars polar nights and compare model results to observations from the Thermal Emission Spectrometer (TES) and the Mars Orbiter Laser Altimeter (MOLA). Model predictions of "cold spots" compare well with TES observations of low emissivity regions, both spatially and as a function of season. The model predicted frequency of CO2 cloud formation also agrees well with MOLA observations of polar night cloud echoes. Together the simulations and observations in the North indicate a distinct shift in atmospheric state centered about Ls 270 which we believe may be associated with the strength of the polar vortex.

40 CFR 600.107-08 - Fuel specifications.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Exhaust Emission Test Procedures § 600.107-08 Fuel specifications. (a) The test fuel specifications for... given in paragraph (b) of this section. (b)(1) Diesel test fuel used for cold temperature FTP testing... alternative fuel for cold temperature FTP testing. (c) Test fuels representing fuel types for which there are...

40 CFR 600.107-08 - Fuel specifications.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Exhaust Emission Test Procedures § 600.107-08 Fuel specifications. (a) The test fuel specifications for... given in paragraph (b) of this section. (b)(1) Diesel test fuel used for cold temperature FTP testing... alternative fuel for cold temperature FTP testing. (c) Test fuels representing fuel types for which there are...

40 CFR 600.107-08 - Fuel specifications.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Exhaust Emission Test Procedures § 600.107-08 Fuel specifications. (a) The test fuel specifications for... given in paragraph (b) of this section. (b)(1) Diesel test fuel used for cold temperature FTP testing... alternative fuel for cold temperature FTP testing. (c) Test fuels representing fuel types for which there are...

Cold in-place recycling using solventless emulsion - phase IV (emulsion qualification and long-term field performance).

DOT National Transportation Integrated Search

2016-05-01

This report looks into how a successful Cold In-Place solventless emulsion behaves and how the emulsion : break test developed in Phase III of this project demonstrates that behavior. Modifications to the test have been : made to improve the consiste...

A fuel-based approach to estimating motor vehicle exhaust emissions

NASA Astrophysics Data System (ADS)

Singer, Brett Craig

Motor vehicles contribute significantly to air pollution problems; accurate motor vehicle emission inventories are therefore essential to air quality planning. Current travel-based inventory models use emission factors measured from potentially biased vehicle samples and predict fleet-average emissions which are often inconsistent with on-road measurements. This thesis presents a fuel-based inventory approach which uses emission factors derived from remote sensing or tunnel-based measurements of on-road vehicles. Vehicle activity is quantified by statewide monthly fuel sales data resolved to the air basin level. Development of the fuel-based approach includes (1) a method for estimating cold start emission factors, (2) an analysis showing that fuel-normalized emission factors are consistent over a range of positive vehicle loads and that most fuel use occurs during loaded-mode driving, (3) scaling factors relating infrared hydrocarbon measurements to total exhaust volatile organic compound (VOC) concentrations, and (4) an analysis showing that economic factors should be considered when selecting on-road sampling sites. The fuel-based approach was applied to estimate carbon monoxide (CO) emissions from warmed-up vehicles in the Los Angeles area in 1991, and CO and VOC exhaust emissions for Los Angeles in 1997. The fuel-based CO estimate for 1991 was higher by a factor of 2.3 +/- 0.5 than emissions predicted by California's MVEI 7F model. Fuel-based inventory estimates for 1997 were higher than those of California's updated MVEI 7G model by factors of 2.4 +/- 0.2 for CO and 3.5 +/- 0.6 for VOC. Fuel-based estimates indicate a 20% decrease in the mass of CO emitted, despite an 8% increase in fuel use between 1991 and 1997; official inventory models predict a 50% decrease in CO mass emissions during the same period. Cold start CO and VOC emission factors derived from parking garage measurements were lower than those predicted by the MVEI 7G model. Current inventories in California appear to understate total exhaust CO and VOC emissions, while overstating the importance of cold start emissions. The fuel-based approach yields robust, independent, and accurate estimates of on-road vehicle emissions. Fuel-based estimates should be used to validate or adjust official vehicle emission inventories before society embarks on new, more costly air pollution control programs.

Aircraft NOx and O3 measurements during wintertime temperature inversions in Salt Lake City, Utah

NASA Astrophysics Data System (ADS)

Womack, C.; Fibiger, D. L.; McDuffie, E. E.; Franchin, A.; Goldberger, L.; Moravek, A.; Middlebrook, A. M.; Thornton, J. A.; Murphy, J. G.; Baasandorj, M.; Brown, S. S.

2017-12-01

The topography of northern Utah results in several multi-day persistent cold-air pools (PCAPs) each winter, during which a temperature inversion prevents the mix-out of anthropogenic emissions. Pollutant levels rise over the course of several days, resulting in particulate matter (PM2.5) levels exceeding the US National Ambient Air Quality Standard of 35 µg/m3, often reaching 60-70 µg/m3 or higher. However, there is significant variability within individual valleys, whose emissions are predominately urban (as in Salt Lake City Valley), agricultural (as in Cache Valley), or a combination of the two. The Utah Winter Fine Particulate Matter Study (UWFPS 2017) was a ground- and aircraft-based field campaign that took place in Jan-Feb 2017 with the aim of better characterizing the complex chemistry involved in the buildup of PM2.5. On board the NOAA Twin Otter aircraft was a cavity ringdown instrument for measuring nitrogen oxides and ozone, an I- CIMS for gas phase oxidized reactive nitrogen, an AMS that measured particulate phase nitrate, and a mid-infrared absorption instrument for NH3. We report vertical and horizontal distributions of NOx, NOy, and O3, and their variation with meteorological conditions and time of day, in the urban and rural valleys of northern Utah.

Three-dimensional mantle dynamics with an endothermic phase transition

NASA Technical Reports Server (NTRS)

Honda, S.; Balachandar, S.; Yuen, D. A.; Reuteler, D.

1993-01-01

3D convection for the spinel to perovskite phase change has been simulated numerically. Results for Rayleigh (Ra) numbers of 0(10 exp 6) show intermittent layering with a strong robust plume rising through the phase boundary. Many descending instabilities are deflected but merging cold sheets come together at a junction. A pool of cold material accumulates underneath in the phase-transition zone. A strong gravitational instability results, which precipitates a rapid and massive discharge of upper-mantle material.

Raining on black holes and massive galaxies: the top-down multiphase condensation model

NASA Astrophysics Data System (ADS)

Gaspari, M.; Temi, P.; Brighenti, F.

2017-04-01

The plasma haloes filling massive galaxies, groups and clusters are shaped by active galactic nucleus (AGN) heating and subsonic turbulence (σv ˜ 150 km s-1), as probed by Hitomi. Novel 3D high-resolution simulations show the soft X-ray, keV hot plasma cools rapidly via radiative emission at the high-density interface of the turbulent eddies, stimulating a top-down condensation cascade of warm 104 K filaments. The kpc-scale ionized (optical/ultraviolet) filaments form a skin enveloping the neutral filaments (optical/infrared/21 cm). The peaks of the warm filaments further condense into cold molecular clouds (<50 K; radio) with total mass of several 107 M⊙ and inheriting the turbulent kinematics. In the core, the clouds collide inelastically, mixing angular momentum and leading to Chaotic Cold Accretion (CCA). The black hole accretion rate (BHAR) can be modelled via quasi-spherical viscous accretion, dot{M}_bullet ∝ ν _c, with clump collisional viscosity νc ≡ λc σv and λc ˜ 100 pc. Beyond the core, pressure torques shape the angular momentum transport. In CCA, the BHAR is recurrently boosted up to 2 dex compared with the disc evolution, which arises as turbulence becomes subdominant. With negligible rotation too, compressional heating inhibits the molecular phase. The CCA BHAR distribution is lognormal with pink noise, f-1 power spectrum characteristic of fractal phenomena. Such chaotic fluctuations can explain the rapid luminosity variability of AGN and high-mass X-ray binaries. An improved criterium to trace non-linear condensation is proposed: σv/vcool ≲ 1. The three-phase CCA reproduces key observations of cospatial multiphase gas in massive galaxies, including Chandra X-ray images, SOAR Hα filaments and kinematics, Herschel [C+] emission and ALMA molecular associations. CCA plays important role in AGN feedback and unification, the evolution of BHs, galaxies and clusters.

High-energy emissions from the gamma-ray binary LS 5039

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

Takata, J.; Leung, Gene C. K.; Cheng, K. S.

2014-07-20

We study mechanisms of multi-wavelength emissions (X-ray, GeV, and TeV gamma-rays) from the gamma-ray binary LS 5039. This paper is composed of two parts. In the first part, we report on results of observational analysis using 4 yr data of the Fermi Large Area Telescope. Due to the improvement of instrumental response function and increase of the statistics, the observational uncertainties of the spectrum in the ∼100-300 MeV bands and >10 GeV bands are significantly improved. The present data analysis suggests that the 0.1-100 GeV emissions from LS 5039 contain three different components: (1) the first component contributes to <1more » GeV emissions around superior conjunction, (2) the second component dominates in the 1-10 GeV energy bands, and (3) the third component is compatible with the lower-energy tail of the TeV emissions. In the second part, we develop an emission model to explain the properties of the phase-resolved emissions in multi-wavelength observations. Assuming that LS 5039 includes a pulsar, we argue that emissions from both the magnetospheric outer gap and the inverse-Compton scattering process of cold-relativistic pulsar wind contribute to the observed GeV emissions. We assume that the pulsar is wrapped by two kinds of termination shock: Shock-I due to the interaction between the pulsar wind and the stellar wind and Shock-II due to the effect of the orbital motion. We propose that the X-rays are produced by the synchrotron radiation at the Shock-I region and the TeV gamma-rays are produced by the inverse-Compton scattering process at the Shock-II region.« less

Formation of complex organic molecules in cold objects: the role of gas-phase reactions

NASA Astrophysics Data System (ADS)

Balucani, Nadia; Ceccarelli, Cecilia; Taquet, Vianney

2015-04-01

While astrochemical models are successful in reproducing many of the observed interstellar species, they have been struggling to explain the observed abundances of complex organic molecules. Current models tend to privilege grain surface over gas-phase chemistry in their formation. One key assumption of those models is that radicals trapped in the grain mantles gain mobility and react on lukewarm ( ≳ 30 K) dust grains. Thus, the recent detections of methyl formate (MF) and dimethyl ether (DME) in cold objects represent a challenge and may clarify the respective role of grain-surface and gas-phase chemistry. We propose here a new model to form DME and MF with gas-phase reactions in cold environments, where DME is the precursor of MF via an efficient reaction overlooked by previous models. Furthermore, methoxy, a precursor of DME, is also synthesized in the gas phase from methanol, which is desorbed by a non-thermal process from the ices. Our new model reproduces fairly well the observations towards L1544. It also explains, in a natural way, the observed correlation between DME and MF. We conclude that gas-phase reactions are major actors in the formation of MF, DME and methoxy in cold gas. This challenges the exclusive role of grain-surface chemistry and favours a combined grain-gas chemistry.

Modeling impacts of cold climates on vehicle emissions : final report.

DOT National Transportation Integrated Search

2017-01-20

Vehicle emissions include carbon monoxide (CO), nitrogen oxides (NOx = NO + NO2), volatile organic compounds (VOCs), and air toxics such as benzene. Each of these pollutants is linked to adverse human health effects. To evaluate the contributions of ...

40 CFR 86.245-94 - [Reserved

Code of Federal Regulations, 2010 CFR

2010-07-01

... EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.245-94 [Reserved] ...

40 CFR 86.220-94 - [Reserved

Code of Federal Regulations, 2010 CFR

2010-07-01

... EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.220-94 [Reserved] ...

40 CFR 86.243-94 - [Reserved

Code of Federal Regulations, 2010 CFR

2010-07-01

... EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.243-94 [Reserved] ...

40 CFR 86.207-94 - [Reserved

Code of Federal Regulations, 2010 CFR

2010-07-01

... EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.207-94 [Reserved] ...

40 CFR 86.225-94 - [Reserved

Code of Federal Regulations, 2010 CFR

2010-07-01

... EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.225-94 [Reserved] ...

40 CFR 86.217-94 - [Reserved

Code of Federal Regulations, 2010 CFR

2010-07-01

... EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.217-94 [Reserved] ...

40 CFR 86.241-94 - [Reserved

Code of Federal Regulations, 2010 CFR

2010-07-01

... EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.241-94 [Reserved] ...

40 CFR 86.210-94 - [Reserved

Code of Federal Regulations, 2010 CFR

2010-07-01

... EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.210-94 [Reserved] ...

40 CFR 86.212-94 - [Reserved

Code of Federal Regulations, 2010 CFR

2010-07-01

... EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.212-94 [Reserved] ...

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.

The winter gap effect in methane leak detection and repair with optical gas imaging cameras

NASA Astrophysics Data System (ADS)

Fox, T. A.; Barchyn, T.; Hugenholtz, C.

2017-12-01

Implementing effective leak detection and repair (LDAR) programs is essential for mitigating fugitive methane emissions from oil and gas operations. In Canada, newly proposed regulations will require that high-risk facilities be surveyed 3 times/yr for fugitive leaks. Like the United States, Canada promotes the use of Optical Gas Imaging cameras (OGIs) for detecting natural gas leaks during LDAR surveys. However, recent research suggests OGIs may perform poorly under adverse environmental conditions, especially in low temperatures. For regions like Canada that experience cold winters, OGIs may not be reliably used for months at a time, meaning that leaks may accumulate and emit for longer periods before being repaired. While considerable oil and gas activity occurs in high-latitude regions with cold winters, no research has explored how extended cold periods impact OGI-focused LDAR programs. To improve this understanding, we present a simple model exploring relationships among winter gap length, fugitive methane emissions, and investment input for LDAR programs employing OGI instruments in gas producing regions of different latitudes. Preliminary results suggest that longer gaps between LDAR surveys caused by cold temperatures result in either 1) higher total emissions for the year, or 2) greater time and equipment investment in LDAR programs to achieve emissions mitigation equivalent to LDAR programs operating under ideal conditions. When weather constraints are removed and LDAR surveys are evenly spaced throughout the year, emissions mitigation is optimized. However, as the winter gap duration and the size of the implicated area increases, fugitive leaks last longer. Furthermore, a spillover effect is observed as LDAR crews become overwhelmed with the high volume of work required as temperatures increase in the spring. Our model adds weight to the argument that LDAR programs should be tailored to regional needs, and that regulators should be more cognisant of sensor-specific limitations as they develop LDAR protocols.

PAHs and the Diffuse Interstellar Bands. What have we Learned from the New Generation of Laboratory and Observational Studies?

NASA Technical Reports Server (NTRS)

Salama, Farid

2005-01-01

Polycyclic Aromatic Hydrocarbons (PAHs) are an important and ubiquitous component of carbon-bearing materials in space. PAHs are the best-known candidates to account for the IR emission bands (UIR bands) and PAH spectral features are now being used as new probes of the ISM. PAHs are also thought to be among the carriers of the diffuse interstellar absorption bands (DIBs). In the model dealing with the interstellar spectral features, PAHs are present as a mixture of radicals, ions and neutral species. PAH ionization states reflect the ionization balance of the medium while PAH size, composition, and structure reflect the energetic and chemical history of the medium. A major challenge for laboratory astrophysics is to reproduce (in a realistic way) the physical conditions that exist in the emission and/or absorption interstellar zones, An extensive laboratory program has been developed at NASA Ames to characterize the physical and chemical properties of PAHs in astrophysical environments and to describe how they influence the radiation and energy balance in space and the interstellar chemistry. In particular, laboratory experiments provide measurements of the spectral characteristics of interstellar PAH analogs from the ultraviolet and visible range to the infrared range for comparison with astronomical data. This paper will focus on the recent progress made in the laboratory to measure the direct absorption spectra of neutral and ionized PAHs in the gas phase in the near-W and visible range in astrophysically relevant environments. These measurements provide data on PAHs and nanometer-sized particles that can now be directly compared to astronomical observations. The harsh physical conditions of the IS medium - characterized by a low temperature, an absence of collisions and strong V W radiation fields - are simulated in the laboratory by associating a molecular beam with an ionizing discharge to generate a cold plasma expansion. PAH ions are formed from the neutral precursors in an isolated environment at low temperature (of the order of 100 K). The spectra of neutral and ionized PAHs are measured using the high sensitivity methods of cavity ring down spectroscopy (CRDS). These experiments provide unique information on the spectra of free, cold large carbon molecules and ions in the gas phase. Intrinsic band profiles and band positions of cold gas-phase PAHs can now be measured with high- sensitivity spectroscopy and directly compared to the astronomical data. The electronic bands measured for ionized PAH are found to be intrinsically broad (about 20/cm) while the bands associated with the neutral precursors are narrower (of the order of 2 - 10/cm).

Spectroscopic method to study low charge state ion and cold electron population in ECRIS plasma

NASA Astrophysics Data System (ADS)

Kronholm, R.; Kalvas, T.; Koivisto, H.; Tarvainen, O.

2018-04-01

The results of optical emission spectroscopy experiments probing the cold electron population of a 14 GHz Electron Cyclotron Resonance Ion Source (ECRIS) are reported. The study has been conducted with a high resolution spectrometer and data acquisition setup developed specifically for the diagnostics of weak emission line characteristic to ECRIS plasmas. The optical emission lines of low charge state ions and neutral atoms of neon have been measured and analyzed with the line-ratio method. The aforementioned electron population temperature of the cold electron population (Te < 100 eV) is determined for Maxwell-Boltzmann and Druyvesteyn energy distributions to demonstrate the applicability of the method. The temperature was found to change significantly when the extraction voltage of the ion source is turned on/off. In the case of the Maxwellian distribution, the temperature of the cold electron population is 20 ± 10 eV when the extraction voltage is off and 40 ± 10 eV when it is on. The optical emission measurements revealed that the extraction voltage also affects both neutral and ion densities. Based on the rate coefficient analysis with the aforementioned temperatures, switching the extraction voltage off decreases the rate coefficient of neutral to 1+ ionization to 42% and 1+ to 2+ ionization to 24% of the original. This suggests that switching the extraction voltage on favors ionization to charge states ≥2+ and, thus, the charge state distributions of ECRIS plasmas are probably different with the extraction voltage on/off. It is therefore concluded that diagnostics results of ECRIS plasmas obtained without the extraction voltage are not depicting the plasma conditions in normal ECRIS operation.

Response of Global Lightning Activity Observed by the TRMM/LIS During Warm and Cold ENSO Phases

NASA Technical Reports Server (NTRS)

Chronis, Themis G.; Cecil, Dan; Goodman, Steven J.; Buechler, Dennis

2007-01-01

This paper investigates the response of global lightning activity to the transition from the warm (January February March-JFM 1998) to the cold (JFM 1999) ENSO phase. The nine-year global lightning climatology for these months from the Tropical Rainfall Measuring Mission (TRMM) Lightning Imaging Sensor (LIS) provides the observational baseline. Flash rate density is computed on a 5.0x5.0 degree lat/lon grid within the LIS coverage area (between approx.37.5 N and S) for each three month period. The flash rate density anomalies from this climatology are examined for these months in 1998 and 1999. The observed lightning anomalies spatially match the documented general circulation features that accompany the warm and cold ENSO events. During the warm ENSO phase the dominant positive lightning anomalies are located mostly over the Western Hemisphere and more specifically over Gulf of Mexico, Caribbean and Northern Mid-Atlantic. We further investigate specifically the Northern Mid-Atlantic related anomaly features since these show strong relation to the North Atlantic Oscillation (NAO). Furthermore these observed anomaly patterns show strong spatial agreement with anomalous upper level (200 mb) cold core cyclonic circulations. Positive sea surface temperature anomalies during the warm ENSO phase also affect the lightning activity, but this is mostly observed near coastal environments. Over the open tropical oceans, there is climatologically less lightning and the anomalies are less pronounced. Warm ENSO related anomalies over the Eastern Hemisphere are most prominent over the South China coast. The transition to the cold ENSO phase illustrates the detected lightning anomalies to be more pronounced over East and West Pacific. A comparison of total global lightning between warm and cold ENSO phase reveals no significant difference, although prominent regional anomalies are located over mostly oceanic environments. All three tropical "chimneys" (Maritime Continent, Central Africa, and Amazon Basin) do not show any particular response to this transition.

Quantum incommensurate skyrmion crystals and commensurate to in-commensurate transitions in cold atoms and materials with spin-orbit couplings in a Zeeman field

NASA Astrophysics Data System (ADS)

Sun, Fadi; Ye, Jinwu; Liu, Wu-Ming

2017-08-01

In this work, we study strongly interacting spinor atoms in a lattice subject to a two dimensional (2d) anisotropic Rashba type of spin orbital coupling (SOC) and an Zeeman field. We find the interplay between the Zeeman field and the SOC provides a new platform to host rich and novel classes of quantum commensurate and in-commensurate phases, excitations and phase transitions. These commensurate phases include two collinear states at low and high Zeeman field, two co-planar canted states at mirror reflected SOC parameters respectively. Most importantly, there are non-coplanar incommensurate Skyrmion (IC-SkX) crystal phases surrounded by the four commensurate phases. New excitation spectra above all the five phases, especially on the IC-SKX phase are computed. Three different classes of quantum commensurate to in-commensurate transitions from the IC-SKX to its four neighboring commensurate phases are identified. Finite temperature behaviors and transitions are discussed. The critical temperatures of all the phases can be raised above that reachable by current cold atom cooling techniques simply by tuning the number of atoms N per site. In view of recent impressive experimental advances in generating 2d SOC for cold atoms in optical lattices, these new many-body phenomena can be explored in the current and near future cold atom experiments. Applications to various materials such as MnSi, {Fe}}0.5 {Co}}0.5Si, especially the complex incommensurate magnetic ordering in Li2IrO3 are given.

Unregulated gaseous exhaust emission from modern ethanol fuelled light duty vehicles in cold ambient condition

NASA Astrophysics Data System (ADS)

Clairotte, M.; Adam, T. W.; Zardini, A. A.; Astorga, C.

2011-12-01

According to Directive 2003/30/EC and 2009/28/EC of the European Parliament and the Council, Member States should promote the use of biofuel. Consequently, all petrol and diesel used for transport purpose available on the market since the 1st of January 2011 must contain a reference value of 5.75% of renewable energy. Ethanol in gasoline could be a promising alternative to comply with this objective, and is actually available in higher proportion in Sweden and Brazil. In addition to a lower dependence on fossil fuel, it is well established that ethanol contributes to reduce air pollutant emissions during combustion (CO, THC), and presents a beneficial effect on the greenhouse gas emissions. However, these statements rely on numerous chassis dynamometer emission studies performed in warm condition (22°C), and very few emission data are available at cold ambient condition encountered in winter, particularly in the north of Europe. In this present study, the effects of ethanol (E75-E85) versus gasoline (E5) have been investigated at cold ambient temperature (-7°C). Experiments have been carried out in a chassis dynamometer at the Vehicle Emission Laboratory (VELA) of the European Commission's Joint Research Centre (JRC - Ispra, Italy). Emissions of modern passenger cars complying with the latest European standard (Euro4 and Euro5a) were tracked over the New European Driving Cycle (NEDC). Unregulated gaseous compounds like greenhouse gases (carbon dioxide, methane, nitrous oxide), and air quality related compounds (ammonia, formaldehyde, acetaldehyde) were monitored by an online Fourier Transformed Infra-Red spectrometer with 1 Hz acquisition frequency. In addition, a number of ozone precursors (carbonyls and volatile organic hydrocarbons) were collected in order to assess the ozone formation potential (OFP) of the exhaust. Results showed higher unregulated emissions at -7°C, regardless of the ethanol content in the fuel blend. Most of the emissions occurred during the first minutes of the cycle, before the light-off of the Three-Way Catalyst (TWC). Less ammonia has been emitted with ethanol fuel, in particular in low ambient condition (E75 versus E5). Ammonia is a harmful compound for human health and vegetation, and is a precursor of secondary aerosol. Even if agricultural activities are the main source of anthropogenic ammonia, the contribution from the transport sector increases significantly during the cold season. Consequently, using high concentrated ethanol as fuel may have a positive impact on ammonia emission in urban area. However, ethanol fuel had a negative impact on formaldehyde and acetaldehyde. The latter together with methane was notably emitted in low ambient temperature, in comparison with gasoline fuel (E5). Moreover, the OFP at -7°C was influenced by the amount of ethanol in gasoline, mainly because of the increase of ozone precursors linked to ethanol (ethylene, acetylene, and acetaldehyde). Even if ozone concentration levels are generally lower during the cold seasons these results show that the issue should be considered globally before promoting the use of high concentrated ethanol fuel in a large scale.

Convective Cold Pool Structure and Boundary Layer Recovery in DYNAMO

NASA Astrophysics Data System (ADS)

Savarin, A.; Chen, S. S.; Kerns, B. W.; Lee, C.; Jorgensen, D. P.

2012-12-01

One of the key factors controlling convective cloud systems in the Madden-Julian Oscillation (MJO) over the tropical Indian Ocean is the property of the atmospheric boundary layer. Convective downdrafts and precipitation from the cloud systems produce cold pools in the boundary layer, which can inhibit subsequent development of convection. The recovery time is the time it takes for the boundary layer to return to pre convective conditions. It may affect the variability of the convection on various time scales during the initiation of MJO. This study examines the convective cold pool structure and boundary layer recovery using the NOAA WP-3D aircraft observations, include the flight-level, Doppler radar, and GPS dropsonde data, collected during the Dynamics of MJO (DYNAMO) field campaign from November-December 2011. The depth and strength of convective cold pools are defined by the negative buoyancy, which can be computed from the dropsonde data. Convective downdraft can be affected by environmental water vapor due to entrainment. Mid-level dry air observed during the convectively suppressed phase of MJO seems to enhance convective downdraft, making the cold pools stronger and deeper. Recovery of the cold pools in the boundary layer is determined by the strength and depth of the cold pools and also the air-sea heat and moisture fluxes. Given that the water vapor and surface winds are distinct for the convectively active and suppressed phases of MJO over the Indian Ocean, the aircraft data are stratified by the two different large-scale regimes of MJO. Preliminary results show that the strength and depth of the cold pools are inversely correlated with the surrounding mid-level moisture. During the convectively suppressed phase, the recovery time is ~5-20 hours in relative weak wind condition with small air-sea fluxes. The recovery time is generally less than 6 hours during the active phase of MJO with moist mid-levels and stronger surface wind and air-sea fluxes.

On the relation between phase path, group path and attenuation in a cold absorbing plasma

NASA Technical Reports Server (NTRS)

Bennett, J. A.; Dyson, P. L.

1978-01-01

Consideration is given to a cold absorbing plasma in which the collision frequency is zero. Expressions are developed which relate the attenuation and the group and phase refractive indices. It is found that because the expressions for the group and phase refractive indices and the imaginary part of the refractive index are closely related in form, the attenuation is related to the difference between the group and phase paths. Numerical calculations have derived approximations which significantly increase the range of known approximations of this type.

The Nature of Cold-induced Dormancy in Urediospores of Puccinia graminis tritici

PubMed Central

Maheshwari, Ramesh; Sussman, Alfred S.

1971-01-01

When air-dry urediospores of the wheat stem rust, Puccinia graminis f. sp. tritici, are exposed to temperatures below freezing, their germinability is markedly reduced, even after prolonged thawing at room temperature. Germinability is fully restored by a brief heat-shock or by vapor phase hydration. We have found that this “cold dormancy” cannot be reversed once the spores contact liquid water. Enhanced loss of metabolites occurs immediately upon suspension of cold-dormant urediospores in liquid without a prior heat-shock. Such leakage is two to three times greater than from untreated or heatshocked cold-dormant spores and accounts for up to 70% of the soluble pool of metabolites normally present in germinating urediospores. Respiratory activity of cold-dormant urediospores declines rapidly during incubation in liquid. Incorporation of isotopic carbon into cold-dormant urediospores is only a fraction of that of untreated or heat-activated spores. Thus, cold shock transforms the spores into a state of supersensitivity to liquid water, which is reversed by heat-shock or slow hydration by vapor phase equilibration. The primary cause of damage to cold-dormant cells exposed to liquid water appears to be irreversible permeability damage, followed by metabolic injury. PMID:16657610

Imaging the cold molecular gas in SDSS J1148 + 5251 at z = 6.4

NASA Astrophysics Data System (ADS)

Stefan, Irina I.; Carilli, Chris L.; Wagg, Jeff; Walter, Fabian; Riechers, Dominik A.; Bertoldi, Frank; Green, David A.; Fan, Xiaohui; Menten, Karl; Wang, Ran

2015-08-01

We present Karl G. Jansky Very Large Array (VLA) observations of the CO (J = 2 → 1) line emission towards the z = 6.419 quasar SDSS J114816.64 + 525150.3 (J1148 + 5251). The molecular gas is found to be marginally resolved with a major axis of 0.9 arcsec (consistent with previous size measurements of the CO (J = 7 → 6) emission). We observe tentative evidence for extended line emission towards the south-west on a scale of ˜1.4 arcsec, but this is only detected at 3.3σ significance and should be confirmed. The position of the molecular emission region is in excellent agreement with previous detections of low-frequency radio continuum emission as well as [C II] line and thermal dust continuum emission. These CO (J = 2 → 1) observations provide an anchor for the low-excitation part of the molecular line spectral energy distribution. We find no evidence for extended low-excitation component, neither in the spectral line energy distribution nor the image. We fit a single kinetic gas temperature model of 50 K. We revisit the gas and dynamical masses in light of this new detection of a low-order transition of CO, and confirm previous findings that there is no extended reservoir of cold molecular gas in J1148 + 5251, and that the source departs substantially from the low-z relationship between black hole mass and bulge mass. Hence, the characteristics of J1148 + 5251 at z = 6.419 are very similar to z ˜ 2 quasars, in the lack of a diffuse cold gas reservoir and kpc-size compactness of the star-forming region.

Analysis of the repeatability of the exhaust pollutants emission research results for cold and hot starts under controlled driving cycle conditions.

PubMed

Jaworski, Artur; Kuszewski, Hubert; Ustrzycki, Adam; Balawender, Krzysztof; Lejda, Kazimierz; Woś, Paweł

2018-04-20

Measurement of car engines exhaust pollutants emissions is very important because of their harmful effects on the environment. This article presents the assessment of repeatability of the passenger car engine exhaust pollutants emission research results obtained in the conditions of a chassis dynamometer. The research was conducted in a climate chamber, enabling the temperature conditions to be determined from - 20 to + 30 °C. The emission of CO, CH 4 , CO 2 , NO X , THC, and NMHC was subjected to the analysis. The aim of the research is to draw attention to the accuracy of the pollutant emission research results in driving cycles, and the comparison of pollutant emission results and their repeatability obtained in successive NEDC cycles under cold and hot start conditions. The results of the analysis show that, in the case of a small number of measurements, the results repeatability analysis is necessary for a proper interpretation of the pollutant emission results on the basis of the mean value. According to the authors' judgment, it is beneficial to determine the coefficient of variation for a more complete assessment of exhaust emission result repeatability obtained from a small number of measurements. This parameter is rarely presented by the authors of papers on exhaust components emission research.

Independent cellular effects of cold ischemia and reperfusion: experimental molecular study.

PubMed

Lledó-García, E; Humanes-Sánchez, B; Mojena-Sánchez, M; Rodrígez, J C J; Hernández-Fernández, C; Tejedor-Jorge, A; Fernández, A L

2013-04-01

There is less information available on cell cultures on the exclusive effects of either duration of cold ischemia (CI) or rewarming-reperfusion in the kidney subjected to initial warm ischemia (WI). Therefore, the goals of our work were: (1) to evaluate the consequences on tubular cellular viability of different durations of CI on a kidney after an initial period of WI, and (2) to analyze the additional effect on tubular cell viability of rewarming of the same kidney. Sixteen mini-pig were used. All the animals were performed a right nephrectomy after 45-minute occlusion of the vascular pedicle. The kidneys were then divided into 2 groups (phase 1): cold storage in university of wisconsin (UW) solution for 3 hours (group A, n = 8) at 4°C, or cold storage in UW for 12 hours (group B, n = 8) at 4°C. Four organs of group A and four organs of group B were autotrasplanted (AT) and reperfused for 1 hour (phase 2). Nephrectomy was finally done. Biopsies were taken from all groups to perform cultures of proximal tubule epithelium cells. The biopsies were subjected to studies of cellular morphological viability (contrast phase microscopy [CPM]) and quantitative (confluence cell [CC]) parameters. Phase of pure CI effects (phase 1): Both CC rate and CPM parameters were significantly lower in group B compared with group A, where cell activity reached almost normal results. Phase of CI + AT (phase 2): At produced additional harmful effects in cell cultures compared with those obtained in phase 1, more evident in group B cells. The presence of cold storage followed by rewarming-reperfusion induces independent and cumulative detrimental effects in viability of renal proximal tubule cells. CI periods ≤ 3 hours may ameliorate the injuries secondary to reperfusion in comparison with longer CI periods. Copyright © 2013 Elsevier Inc. All rights reserved.

Emissions from cold heavy oil production with sands (CHOPS) facilities in Alberta, Canada

NASA Astrophysics Data System (ADS)

Roscioli, J. R.; Herndon, S. C.; Yacovitch, T. I.; Knighton, W. B.; Zavala-Araiza, D.; Johnson, M. R.; Tyner, D. R.

2017-12-01

Cold heavy oil production with sands (CHOPS) is generally characterized as a pump driven oil extraction method producing a mixture of sand, water, and heavy oil to heated liquid storage tanks. In addition to fluids, CHOPS sites also produce solution gas, primarily composed of methane, through the well annulus. Depending on formation and well production characteristics, large volumes of this solution gas are frequently vented to the atmosphere without flaring or conservation. To better understand these emission we present measurements of methane, ethane, propane and aromatic emission rates from CHOPS sites using dual tracer flux ratio methodology. The use of two tracers allowed on-site emission sources to be accurately identified and in one instance indicated that the annular vent was responsible for >75% of emissions at the facility. Overall, a measurement survey of five CHOPS sites finds that the methane emissions are in general significantly under-reported by operators. This under-reporting may arise from uncertainties associated with measured gas-to-oil ratios upon which the reported vent volume is based. Finally, measurements of ethane, propane and aromatics from these facilities indicates surprisingly low non-methane hydrocarbon content.

Carbon nanotube emitters and field emission triode

NASA Astrophysics Data System (ADS)

Fan, Zhiqin; Zhang, Binglin; Yao, Ning; Zhang, Lan; Ma, Huizhong; Deng, Jicai

2006-05-01

Based on our study on field emission from multi-walled carbon nanotubes (MWNTs), we experimentally manufactured field emission display (FED) triode with a MWNTs cold cathode, and demonstrated an excellent performance of MWNTs as field emitters. The measured luminance of the phosphor screens was 1.8*10^(3) cd/m2 for green light. The emission is stable with a fluctuation of only 1.5% at an average current of 260 'mu'A.

The Planck Catalogue of Galactic Cold Clumps : PGCC

NASA Astrophysics Data System (ADS)

Montier, L.

The Planck satellite has provided an unprecedented view of the submm sky, allowing us to search for the dust emission of Galactic cold sources. Combining Planck-HFI all-sky maps in the high frequency channels with the IRAS map at 100um, we built the Planck catalogue of Galactic Cold Clumps (PGCC, Planck 2015 results. XXVIII), counting 13188 sources distributed over the whole sky, and following mainly the Galactic structures at low and intermediate latitudes. This is the first all-sky catalogue of Galactic cold sources obtained with a single instrument at this resolution and sensitivity, which opens a new window on star-formation processes in our Galaxy.

Development of a single-phase thermosiphon for cold collection and storage of radiative cooling

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

Zhao, Dongliang; Martini, Christine Elizabeth; Jiang, Siyu

A single-phase thermosiphon is developed for cold collection and storage of radiative cooling. Compared to the conventional nocturnal radiative cooling systems that use an electric pump to drive the heat transfer fluid, the proposed single-phase thermosiphon uses the buoyancy force to drive heat transfer fluid. This solution does not require electricity, therefore improving the net gain of the radiative cooling system. A single-phase thermosiphon was built, which consists of a flat panel, a cold collection tank, a water return tube, and a water distribution tank. Considering that outdoor radiative cooling flux is constantly changing (i.e. uncontrollable), an indoor testing facilitymore » was developed to provide a controllable cooling flux (comparable to a radiative cooling flux of 100 W/m2) for the evaluation of thermosiphon performance. The testing apparatus is a chilled aluminum flat plate that has a controlled air gap separation relative to the flat panel surface of the thermosiphon to emulate radiative cooling. With an average of 105 W/m2 cooling flux, the 18 liters of water in the thermosiphon was cooled to an average temperature of 12.5 degrees C from an initial temperature of 22.2 degrees C in 2 h, with a cold collection efficiency of 96.8%. The results obtained have demonstrated the feasibility of using a single-phase thermosiphon for cold collection and storage of radiative cooling. Additionally, the effects of the thermosiphon operation conditions, such as tilt angle of the flat panel, initial water temperature, and cooling energy flux, on the performance have been experimentally investigated. Modular design of the single-phase thermosiphon gives flexibility for its scalability. A radiative cooling system with multiple thermosiphon modules is expected to play an important role in cooling buildings and power plant condensers.« less

Efficient cold cathode emission in crystalline-amorphous hybrid: Study on carbon nanotube-cadmium selenide system

NASA Astrophysics Data System (ADS)

Sarkar, S.; Banerjee, D.; Das, N. S.; Ghorai, U. K.; Sen, D.; Chattopadhyay, K. K.

2018-03-01

Cadmium Selenide (CdSe) quantum dot (QD) decorated amorphous carbon nanotubes (a-CNTs) hybrids have been synthesized by simple chemical process. The samples were characterized by field emission scanning and transmission electron microscopy, Fourier transformed infrared spectroscopy, Raman and UV-Vis spectroscopy. Lattice image obtained from transmission electron microscopic study confirms the successful attachment of CdSe QDs. It is seen that hybrid samples show an enhanced cold emission properties with good stability. The results have been explained in terms of increased roughness, more numbers of emitting sites and favorable band bending induced electron transport. ANSYS software based calculation has also supported the result. Also a first principle based study has been done which shows that due to the formation of hybrid structure there is a profound upward shift in the Fermi level, i.e. a decrease of work function, which is believed to be another key reason for the observed improved field emission performance.

Spent nuclear fuel project cold vacuum drying facility operations manual

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

IRWIN, J.J.

This document provides the Operations Manual for the Cold Vacuum Drying Facility (CVDF). The Manual was developed in conjunction with HNF-SD-SNF-SAR-002, Safety Analysis Report for the Cold Vacuum Drying Facility, Phase 2, Supporting Installation of Processing Systems (Garvin 1998) and, the HNF-SD-SNF-DRD-002, 1997, Cold Vacuum Drying Facility Design Requirements, Rev. 3a. The Operations Manual contains general descriptions of all the process, safety and facility systems in the CVDF, a general CVD operations sequence, and has been developed for the SNFP Operations Organization and shall be updated, expanded, and revised in accordance with future design, construction and startup phases of themore » CVDF until the CVDF final ORR is approved.« less

Cold Heat Storage Characteristics of O/W-type Latent Heat Emulsion Including Continuum Phase of Water Treated with a Freezing Point Depression

NASA Astrophysics Data System (ADS)

Inaba, Hideo; Morita, Shin-Ichi

This paper deals with flow and cold heat storage characteristics of the oil (tetradecane, C14H30, freezing point 278.9 K, Latent heat 229 kJ/kg)/water emulsion as a latent heat storage material having a low melting point. The test emulsion includes a water-urea solution as a continuum phase. The freezing point depression of the continuum phase permits enhancement of the heat transfer rate of the emulison, due to the large temperature difference between the latent heat storage material and water-urea solution. The velocity of emulsion flow and the inlet temperature of coolant in a coiled double tube heat exchanger are chosen as the experimental parameters. The pressure drop, the heat transfer coefficient of the emulsion in the coiled tube are measured in the temperture region over solid and liquid phase of the latent heat storage material. The finishing time of the cold heat storage is defined experimentally in the range of sensible and latent heat storage. It is clarified that the flow behavior of the emulsion as a non-Newtonian fluid has an important role in cold heat storage. The useful nondimentional correlation equations for the additional pressure loss coefficient, the heat transfer coefficient and the finishing time of the cold heat storage are derived in terms of Dean number and heat capacity ratio.

Cold-stress response during the stationary-growth phase of Antarctic and temperate-climate Penicillium strains.

PubMed

Miteva-Staleva, Jeni G; Krumova, Ekaterina T; Vassilev, Spassen V; Angelova, Maria B

2017-07-01

Cold-induced oxidative stress during the aging of three Penicillium strains (two Antarctic and one from a temperate region) in stationary culture was documented and demonstrated a significant increase in the protein carbonyl content, the accumulation of glycogen and trehalose, and an increase in the activities of antioxidant enzymes (superoxide dismutase and catalase). The cell response to a temperature downshift depends on the degree of stress and the temperature characteristics of the strains. Our data give further support for the role of oxidative stress in the aging of fungi in stationary cultures. Comparing the present results for the stationary growth phase with our previous results for the exponential growth phase was informative concerning the relationship between the cold-stress response and age-related changes in the tested strains. Unlike the young cells, stationary-phase cultures demonstrated a more pronounced level of oxidative damage, as well as decreased antioxidant defence.

Lifecycle of laser-produced air sparks

DOE PAGES

Harilal, S. S.; Brumfield, B. E.; Phillips, M. C.

2015-06-03

Here, we investigated the lifecycle of laser-generated air sparks or plasmas using multiple plasma diagnostic tools. The sparks were generated by focusing the fundamental radiation from an Nd:YAG laser in air, and studies included early and late time spark dynamics, decoupling of the shock wave from the plasma core, emission from the spark kernel, cold gas excitation by UV radiation, shock waves produced by the air spark, and the spark's final decay and turbulence formation. The shadowgraphic and self-emission images showed similar spark morphology at earlier and late times of its lifecycle; however, significant differences are seen in the midlifemore » images. Spectroscopic studies in the visible region showed intense blackbody-type radiation at early times followed by clearly resolved ionic, atomic, and molecular emission. The detected spectrum at late times clearly contained emission from both CN and N 2 +. Additional spectral features have been identified at late times due to emission from O and N atoms, indicating some degree of molecular dissociation and excitation. Detailed spatially and temporally resolved emission analysis provides insight about various physical mechanisms leading to molecular and atomic emission by air sparks, including spark plasma excitation, heating of cold air by UV radiation emitted by the spark, and shock-heating.« less

Lifecycle of laser-produced air sparks

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

Harilal, S. S., E-mail: hari@pnnl.gov; Brumfield, B. E.; Phillips, M. C.

2015-06-15

We investigated the lifecycle of laser-generated air sparks or plasmas using multiple plasma diagnostic tools. The sparks were generated by focusing the fundamental radiation from an Nd:YAG laser in air, and studies included early and late time spark dynamics, decoupling of the shock wave from the plasma core, emission from the spark kernel, cold gas excitation by UV radiation, shock waves produced by the air spark, and the spark's final decay and turbulence formation. The shadowgraphic and self-emission images showed similar spark morphology at earlier and late times of its lifecycle; however, significant differences are seen in the midlife images.more » Spectroscopic studies in the visible region showed intense blackbody-type radiation at early times followed by clearly resolved ionic, atomic, and molecular emission. The detected spectrum at late times clearly contained emission from both CN and N{sub 2}{sup +}. Additional spectral features have been identified at late times due to emission from O and N atoms, indicating some degree of molecular dissociation and excitation. Detailed spatially and temporally resolved emission analysis provides insight about various physical mechanisms leading to molecular and atomic emission by air sparks, including spark plasma excitation, heating of cold air by UV radiation emitted by the spark, and shock-heating.« less

The influence of Ag+Mg additions on the nucleation of strengthening precipitates in a non-cold-worked Al-Cu-Li alloy

NASA Technical Reports Server (NTRS)

1991-01-01

Aluminum-copper-lithium alloys generally require cold work to attain their highest strengths in artificially aged tempers. These alloys are usually strengthened by a combination of the metastable delta prime (Al3Li) and theta prime (Al2Cu) phases and the equilibrium T sub 1 (Al2CuLi) phase, and where the T sub 1 phase is a more potent strengthener than the delta prime. Various investigators have shown that the high strengths obtained after artificial aging associated with cold work result from the heterogeneous precipitation of T sub 1 on matrix dislocations. The objective here is to elucidate the mechanism by which the Ag+Mg additions stimulate the precipitation of T sub 1 type precipitates without cold work. To accomplish this, the microstructure of an Al-6.3Cu-1.3Li-0.14Zr model alloy was evaluated in a T6 type temper with and without the Ag+Mg addition.

Effect of Natural Aging and Cold Working on Microstructures and Mechanical Properties of Al-4.6Cu-0.5Mg-0.5Ag alloy

NASA Astrophysics Data System (ADS)

Chen, Yu-Te; Lee, Sheng-Long; Bor, Hui-Yun; Lin, Jing-Chie

2013-06-01

This research investigates the effects of natural aging and cold working prior to artificial aging on microstructures and mechanical properties of Al-4.6Cu-0.5Mg-0.5Ag alloy. Mechanical properties relative to microstructure variations were elucidated by the observations of the optical microscope (OM), differential scanning calorimeter (DSC), electrical conductivity meter (pct IACS), and transmission electron microscopy (TEM). The results showed that natural aging treatment has little noticeable benefit on the quantity of precipitation strengthening phases and mechanical properties, but it increases the precipitation strengthening rate at the initial stage of artificial aging. Cold working brings more lattice defects which suppress Al-Cu (GP zone) and Mg-Ag clustering, and therefore the precipitation of Ω phase decreases. Furthermore, more dislocations are formed, leading to precipitate the more heterogeneous nucleation of θ' phase. The above-mentioned precipitation phenomena and strain hardening effect are more obvious with higher degrees of cold working.

Organic compounds in PM 2.5 emitted from fireplace and woodstove combustion of typical Portuguese wood species

NASA Astrophysics Data System (ADS)

Gonçalves, Cátia; Alves, Célia; Fernandes, Ana Patrícia; Monteiro, Cristina; Tarelho, Luís; Evtyugina, Margarita; Pio, Casimiro

2011-09-01

The aim of this study is the further characterisation of PM 2.5 emissions from the residential wood combustion of common woods grown in Portugal. This new research extends to eight the number of biomass fuels studied and tries to understand the differences that the burning appliance (fireplace versus woodstove) and the combustion temperature (cold and hot start) have on emissions. Pinus pinaster (Maritime pine), Eucalyptus globulus (eucalypt), Quercus suber (cork oak), Acacia longifolia (Golden wattle), Quercus faginea (Portuguese oak), Olea europea (Olive), Quercus ilex rotundifolia (Holm oak) and briquettes produced from forest biomass waste were used in the combustion tests. Determinations included fine particle emission factors, carbonaceous content (OC and EC) by a thermal-optical transmission technique and detailed identification and quantification of organic compounds by gas chromatography-mass spectrometry. Fine particle emission factors from the woodstove were lower than those from the fireplace. For both combustion appliances, the OC/EC ratio was higher in "cold start" tests (1.56 ± 0.95 for woodstove and 2.03 ± 1.34 for fireplace). These "cold start" OC/EC values were, respectively, for the woodstove and the fireplace, 51% and 69% higher than those obtained in "hot start" experiments. The chromatographically resolved organics included n-alkanes, n-alkenes, PAHs, n-alkanals, ketones, n-alkanols, terpenoids, triterpenoids, phenolic compounds, phytosterols, alcohols, n-alkanoic acids, n-di-acids, unsaturated acids and alkyl esters of acids. The smoke emission rate and composition varied widely depending on fuel type, burning appliance and combustion temperature.

Estimation of cold plasma outflow during geomagnetic storms

NASA Astrophysics Data System (ADS)

Haaland, S.; Eriksson, A.; André, M.; Maes, L.; Baddeley, L.; Barakat, A.; Chappell, R.; Eccles, V.; Johnsen, C.; Lybekk, B.; Li, K.; Pedersen, A.; Schunk, R.; Welling, D.

2015-12-01

Low-energy ions of ionospheric origin constitute a significant contributor to the magnetospheric plasma population. Measuring cold ions is difficult though. Observations have to be done at sufficiently high altitudes and typically in regions of space where spacecraft attain a positive charge due to solar illumination. Cold ions are therefore shielded from the satellite particle detectors. Furthermore, spacecraft can only cover key regions of ion outflow during segments of their orbit, so additional complications arise if continuous longtime observations, such as during a geomagnetic storm, are needed. In this paper we suggest a new approach, based on a combination of synoptic observations and a novel technique to estimate the flux and total outflow during the various phases of geomagnetic storms. Our results indicate large variations in both outflow rates and transport throughout the storm. Prior to the storm main phase, outflow rates are moderate, and the cold ions are mainly emanating from moderately sized polar cap regions. Throughout the main phase of the storm, outflow rates increase and the polar cap source regions expand. Furthermore, faster transport, resulting from enhanced convection, leads to a much larger supply of cold ions to the near-Earth region during geomagnetic storms.

Estimation of cold plasma outflow during geomagnetic storms

NASA Astrophysics Data System (ADS)

Haaland, S.; Eriksson, A. I.; Andre, M.; Maes, L.; Baddeley, L. J.; Barakat, A. R.; Chappell, C. R.; Eccles, V.; Johnsen, C.; Lybekk, B.; Li, K.; Pedersen, A.; Schunk, R. W.; Welling, D. T.

2015-12-01

Low energy ions of ionospheric origin provide a significant contributon to the magnetospheric plasmapopulation. Measuring cold ions is difficult though. Observations have to be done at sufficiently high altitudes and typically in regions of space where spacecraft attain a positive charge due to solar illumination. Cold ions are therefore shielded from the satellite particle detectors. Furthermore, spacecraft can only cover key regions of ion outflow during segments of their orbit, so additional complications arise arise if continuous longtime observations such as the during a geomagnetic storms are needed. In this paper we suggest a new approach, based on a combination of synoptic observations and a novel technique to estimate the flux and total outflow during the various phases of geomagnetic storms. Our results indicate large variations in both outflow rates and transport throughout the storm. Prior to the storm main phase, outflow rates are moderate, and the cold ions are mainly emanating from moderately sized polar cap regions. Throughout the main phase of the storm, outflow rates increase and the polar cap source regions expand. Furthermore, faster transport, resulting from enhanced convection, leads to a much larger supply of cold ions to the near Earth region during gemagnetic storms.

Cold Fronts Research Programme: Progress, Future Plans, and Research Directions.

NASA Astrophysics Data System (ADS)

Ryan, B. F.; Wilson, K. J.; Garratt, J. R.; Smith, R. K.

1985-09-01

Following the analysis of data collected during Phases land II of the Cold Fronts Research Programme (CFRP) a conceptual model for the Australian summertime "cool change" has been proposed. The model provides a focus and a framework for the design of Phase III.The model is based on data gathered from a mesoscale network centered on Mount Gambier, South Australia, and includes the coastal waters to the west and relatively flat terrain to the east. The first objective of Phase III is to generalize the model so that it is applicable to the ocean waters to the far west of Mount Gambier and to the more rugged terrain farther to the east in the vicinity of Melbourne, Victoria. The remaining objectives concentrate on resolving unsatisfactory aspects of the model such as the evolution of convective lines and the relationship between the surface cold front and the upper-tropospheric cold pool and its associated jet stream.The integrated nature of the Cold Fronts Research Programme has meant that it has stimulated a wide range of research activities that extend beyond the field observations. The associated investigations include climatological, theoretical, and numerical modeling studies.

The Thermal Pressure in Low Metallicity Galaxies

NASA Astrophysics Data System (ADS)

Wolfire, Mark; McKee, Christopher; Ostriker, Eve C.; Bolatto, Alberto; Jenkins, Edward

2015-08-01

The thermal pressure in the diffuse interstellar medium (ISM) is a relatively small fraction of the total ISM pressure yet it is extremely important for the evolution of the ISM phases. A multi-phase medium can exist between a range of thermal pressures Pmin < Pth < Pmax. The phase separation is driven by thermal instability and produces a cold (T ˜ 100 K) neutral atomic gas and a warm (T ˜ 8000 K) neutral atomic gas separated by thermally unstable gas. At thermal pressures greater than Pmax only the cold phase can exist and at thermal pressures less than Pmin only the warm phase can exist. The ISM is also highly turbulent and turbulence can both initiate the thermal phase transition and be produced in a rapid phase transition. Hydrodynamic modeling also points to a strong two-phase distribution (.e.g., Kim et al. 2011; Audit & Hennebelle 2010) with a median thermal pressure in the cold gas very near the expected two-phase pressure. Global, theoretical models including star-formation feedback have been developed for the molecular fraction in galactic disks using, at their core, the paradigm that thermal pressure determines the phase transitions to warm, cold, or multiphase medium (e.g., Krumholz et al. 2009; Ostriker et al. 2010).Here we present a phase diagram for a low metallicity galaxy using the Small Magellanic Clouds as an example. We find that although the heating rates and metallicities can differ by factors of 5 to 10 from the Milky Way, the resulting two-phase pressure and physical conditions of the phases are not very different from Galactic. We also confirm that a widely used fitting function for Pmin presented in Wolfire et al. 2003 provides an accurate prediction for the new results. We demonstrate how the variation in input parameters determine the final pressures and physical conditions.

The SCUBA-2 850 μm Follow-up of WISE-selected, Luminous Dust-obscured Quasars

NASA Astrophysics Data System (ADS)

Fan, Lulu; Jones, Suzy F.; Han, Yunkun; Knudsen, Kirsten K.

2017-12-01

Hot dust-obscured galaxies (Hot DOGs) are a new population recently discovered in the Wide-field Infrared Survey Explorer All-Sky survey. Multiwavelength follow-up observations suggest that they are luminous, dust-obscured quasars at high redshift. Here we present the JCMT SCUBA-2 850 μm follow-up observations of 10 Hot DOGs. Four out of ten Hot DOGs have been detected at >3σ level. Based on the IR SED decomposition approach, we derive the IR luminosities of AGN torus and cold dust components. Hot DOGs in our sample are extremely luminous with most of them having {L}{IR}{tot}> {10}14 {L}⊙ . The torus emissions dominate the total IR energy output. However, the cold dust contribution is still non-negligible, with the fraction of the cold dust contribution to the total IR luminosity (˜8%-24%) being dependent on the choice of torus model. The derived cold dust temperatures in Hot DOGs are comparable to those in UV bright quasars with similar IR luminosity, but much higher than those in SMGs. Higher dust temperatures in Hot DOGs may be due to the more intense radiation field caused by intense starburst and obscured AGN activities. Fourteen and five submillimeter serendipitous sources in the 10 SCUBA-2 fields around Hot DOGs have been detected at >3σ and >3.5σ levels, respectively. By estimating their cumulative number counts, we confirm the previous argument that Hot DOGs lie in dense environments. Our results support the scenario in which Hot DOGs are luminous, dust-obscured quasars lying in dense environments, and being in the transition phase between extreme starburst and UV-bright quasars.

40 CFR 86.203-94 - Abbreviations.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.203-94 Abbreviations. The abbreviations in subpart...

40 CFR 86.246-94 - Intermediate temperature testing.

Code of Federal Regulations, 2010 CFR

2010-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.246-94 Intermediate...

40 CFR 86.213-04 - Fuel specifications.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.213-04 Fuel specifications. Gasoline...

40 CFR 86.213-94 - Fuel specifications.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.213-94 Fuel specifications. Gasoline...

40 CFR 86.218-94 - Dynamometer calibration.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.218-94 Dynamometer calibration. The...

40 CFR 86.224-94 - Carbon dioxide analyzer calibration.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 18 2011-07-01 2011-07-01 false Carbon dioxide analyzer calibration... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission... New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.224-94 Carbon dioxide...

40 CFR 86.222-94 - Carbon monoxide analyzer calibration.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 18 2011-07-01 2011-07-01 false Carbon monoxide analyzer calibration... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission... New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.222-94 Carbon monoxide...

DHIGLS: DRAO H I Intermediate Galactic Latitude Survey

NASA Astrophysics Data System (ADS)

Blagrave, K.; Martin, P. G.; Joncas, G.; Kothes, R.; Stil, J. M.; Miville-Deschênes, M. A.; Lockman, Felix J.; Taylor, A. R.

2017-01-01

Observations of Galactic H I gas for seven targeted regions at intermediate Galactic latitude are presented at 1\\prime angular resolution using data from the DRAO Synthesis Telescope (ST) and the Green Bank Telescope (GBT). The DHIGLS data are the most extensive arcminute-resolution measurements of the diffuse atomic interstellar medium beyond those in the Galactic plane. The acquisition, reduction, calibration, and mosaicking of the DRAO ST data and the cross calibration and incorporation of the short-spacing information from the GBT are described. The high quality of the resulting DHIGLS products enables a variety of new studies in directions of low Galactic column density. We analyze the angular power spectra of maps of the integrated H I emission (column density) from the data cubes for several distinct velocity ranges. In fitting power-spectrum models based on a power law, but including the effects of the synthesized beam and noise at high spatial frequencies, we find exponents ranging from -2.5 to -3.0. Power spectra of maps of the centroid velocity for these components give similar results. These exponents are interpreted as being representative of the three-dimensional density and velocity fields of the atomic gas, respectively. We find evidence for dramatic changes in the H I structures in channel maps over even small changes in velocity. This narrow line emission has counterparts in absorption spectra against bright background radio sources, quantifying that the gas is cold and dense and can be identified as the cold neutral medium phase. Fully reduced DHIGLS H I data cubes and other data products are available at www.cita.utoronto.ca/DHIGLS.

Particulate matter speciation profiles for light-duty gasoline vehicles in the United States.

PubMed

Sonntag, Darrell B; Baldauf, Richard W; Yanca, Catherine A; Fulper, Carl R

2014-05-01

Representative profiles for particulate matter particles less than or equal to 2.5 microm (PM2.5) are developed from the Kansas City Light-Duty Vehicle Emissions Study for use in the US. Environmental Protection Agency (EPA) vehicle emission model, the Motor Vehicle Emission Simulator (MOVES), and for inclusion in the EPA SPECIATE database for speciation profiles. The profiles are compatible with the inputs of current photochemical air quality models, including the Community Multiscale Air Quality Aerosol Module Version 6 (AE6). The composition of light-duty gasoline PM2.5 emissions differs significantly between cold start and hot stabilized running emissions, and between older and newer vehicles, reflecting both impacts of aging/deterioration and changes in vehicle technology. Fleet-average PM2.5 profiles are estimated for cold start and hot stabilized running emission processes. Fleet-average profiles are calculated to include emissions from deteriorated high-emitting vehicles that are expected to continue to contribute disproportionately to the fleet-wide PM2.5 emissions into the future. The profiles are calculated using a weighted average of the PM2.5 composition according to the contribution of PM2.5 emissions from each class of vehicles in the on-road gasoline fleet in the Kansas City Metropolitan Statistical Area. The paper introduces methods to exclude insignificant measurements, correct for organic carbon positive artifact, and control for contamination from the testing infrastructure in developing speciation profiles. The uncertainty of the PM2.5 species fraction in each profile is quantified using sampling survey analysis methods. The primary use of the profiles is to develop PM2.5 emissions inventories for the United States, but the profiles may also be used in source apportionment, atmospheric modeling, and exposure assessment, and as a basis for light-duty gasoline emission profiles for countries with limited data. PM2.5 speciation profiles were developed from a large sample of light-duty gasoline vehicles tested in the Kansas City area. Separate PM2.5 profiles represent cold start and hot stabilized running emission processes to distinguish important differences in chemical composition. Statistical analysis was used to construct profiles that represent PM2.5 emissions from the U.S. vehicle fleet based on vehicles tested from the 2005 calendar year Kansas City metropolitan area. The profiles have been incorporated into the EPA MOVES emissions model, as well as the EPA SPECIATE database, to improve emission inventories and provide the PM2.5 chemical characterization needed by CMAQv5.0 for atmospheric chemistry modeling.

Changes in Sea Salt Emissions Enhance ENSO Variability

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

Yang, Yang; Russell, Lynn M.; Lou, Sijia

Two 150-year pre-industrial simulations with and without interactive sea salt emissions from the Community Earth System Model (CESM) are performed to quantify the interactions between sea salt emissions and El Niño–Southern Oscillation (ENSO). Variations in sea salt emissions over the tropical Pacific Ocean are affected by changing wind speed associated with ENSO variability. ENSO-induced interannual variations in sea salt emissions result in decreasing (increasing) aerosol optical depth (AOD) by 0.03 over the equatorial central-eastern (western) Pacific Ocean during El Niño events compared to those during La Niña events. These changes in AOD further increase (decrease) radiative fluxes into the atmospheremore » by +0.2 W m -2 (-0.4 W m -2) over the tropical eastern (western) Pacific. Thereby, sea surface temperature increases (decreases) by 0.2–0.4 K over the tropical eastern (western) Pacific Ocean during El Niño compared to La Niña events and enhances ENSO variability by 10%. The increase in ENSO amplitude is a result of systematic heating (cooling) during the warm (cold) phase, of ENSO in the eastern Pacific. Interannual variations in sea salt emissions then produce the anomalous ascent (subsidence) over the equatorial eastern (western) Pacific between El Niño and La Niña events, which is a result of heating anomalies. Due to variations in sea salt emissions, the convective precipitation is enhanced by 0.6–1.2 mm day -1 over the tropical central-eastern Pacific Ocean and weakened by 0.9–1.5 mm day -1 over the Maritime Continent during El Niño compared to La Niña events, enhancing the precipitation variability over the tropical Pacific.« less

Arrays of Bundles of Carbon Nanotubes as Field Emitters

NASA Technical Reports Server (NTRS)

Manohara, Harish; Bronkowski, Michael

2007-01-01

Experiments have shown that with suitable choices of critical dimensions, planar arrays of bundles of carbon nanotubes (see figure) can serve as high-current-density field emitter (cold-cathode) electron sources. Whereas some hot-cathode electron sources must be operated at supply potentials of thousands of volts, these cold-cathode sources generate comparable current densities when operated at tens of volts. Consequently, arrays of bundles of carbon nanotubes might prove useful as cold-cathode sources in miniature, lightweight electron-beam devices (e.g., nanoklystrons) soon to be developed. Prior to the experiments, all reported efforts to develop carbon-nanotube-based field-emission sources had yielded low current densities from a few hundred microamperes to a few hundred milliamperes per square centimeter. An electrostatic screening effect, in which taller nanotubes screen the shorter ones from participating in field emission, was conjectured to be what restricts the emission of electrons to such low levels. It was further conjectured that the screening effect could be reduced and thus emission levels increased by increasing the spacing between nanotubes to at least by a factor of one to two times the height of the nanotubes. While this change might increase the emission from individual nanotubes, it would decrease the number of nanotubes per unit area and thereby reduce the total possible emission current. Therefore, to maximize the area-averaged current density, it would be necessary to find an optimum combination of nanotube spacing and nanotube height. The present concept of using an array of bundles of nanotubes arises partly from the concept of optimizing the spacing and height of field emitters. It also arises partly from the idea that single nanotubes may have short lifetimes as field emitters, whereas bundles of nanotubes could afford redundancy so that the loss of a single nanotube would not significantly reduce the overall field emission.

Demonstration of spatial-light-modulation-based four-wave mixing in cold atoms

NASA Astrophysics Data System (ADS)

Juo, Jz-Yuan; Lin, Jia-Kang; Cheng, Chin-Yao; Liu, Zi-Yu; Yu, Ite A.; Chen, Yong-Fan

2018-05-01

Long-distance quantum optical communications usually require efficient wave-mixing processes to convert the wavelengths of single photons. Many quantum applications based on electromagnetically induced transparency (EIT) have been proposed and demonstrated at the single-photon level, such as quantum memories, all-optical transistors, and cross-phase modulations. However, EIT-based four-wave mixing (FWM) in a resonant double-Λ configuration has a maximum conversion efficiency (CE) of 25% because of absorptive loss due to spontaneous emission. An improved scheme using spatially modulated intensities of two control fields has been theoretically proposed to overcome this conversion limit. In this study, we first demonstrate wavelength conversion from 780 to 795 nm with a 43% CE by using this scheme at an optical density (OD) of 19 in cold 87Rb atoms. According to the theoretical model, the CE in the proposed scheme can further increase to 96% at an OD of 240 under ideal conditions, thereby attaining an identical CE to that of the previous nonresonant double-Λ scheme at half the OD. This spatial-light-modulation-based FWM scheme can achieve a near-unity CE, thus providing an easy method of implementing an efficient quantum wavelength converter for all-optical quantum information processing.

Cold Shock Induction of Thermal Sensitivity in Listeria monocytogenes

PubMed Central

Miller, Arthur J.; Bayles, Darrell O.; Eblen, B. Shawn

2000-01-01

Cold shock at 0 to 15°C for 1 to 3 h increased the thermal sensitivity of Listeria monocytogenes. In a model broth system, thermal death time at 60°C was reduced by up to 45% after L. monocytogenes Scott A was cold shocked for 3 h. The duration of the cold shock affected thermal tolerance more than did the magnitude of the temperature downshift. The Z values were 8.8°C for controls and 7.7°C for cold-shocked cells. The D values of cold-shocked cells did not return to control levels after incubation for 3 h at 28°C followed by heating at 60°C. Nine L. monocytogenes strains that were cold shocked for 3 h exhibited D60 values that were reduced by 13 to 37%. The D-value reduction was greatest in cold-shocked stationary-phase cells compared to cells from cultures in either the lag or exponential phases of growth. In addition, cold-shocked cells were more likely to be inactivated by a given heat treatment than nonshocked cells, which were more likely to experience sublethal injury. The D values of chloramphenicol-treated control cells and chloramphenicol-treated cold-shocked cells were no different from those of untreated cold-shocked cells, suggesting that cold shock suppresses synthesis of proteins responsible for heat protection. In related experiments, the D values of L. monocytogenes Scott A were decreased 25% on frankfurter skins and 15% in ultra-high temperature milk if the inoculated products were first cold shocked. Induction of increased thermal sensitivity in L. monocytogenes by thermal flux shows potential to become a practical and efficacious preventative control method. PMID:11010880

Antiphase light and temperature cycles affect PHYTOCHROME B-controlled ethylene sensitivity and biosynthesis, limiting leaf movement and growth of Arabidopsis.

PubMed

Bours, Ralph; van Zanten, Martijn; Pierik, Ronald; Bouwmeester, Harro; van der Krol, Alexander

2013-10-01

In the natural environment, days are generally warmer than the night, resulting in a positive day/night temperature difference (+DIF). Plants have adapted to these conditions, and when exposed to antiphase light and temperature cycles (cold photoperiod/warm night [-DIF]), most species exhibit reduced elongation growth. To study the physiological mechanism of how light and temperature cycles affect plant growth, we used infrared imaging to dissect growth dynamics under +DIF and -DIF in the model plant Arabidopsis (Arabidopsis thaliana). We found that -DIF altered leaf growth patterns, decreasing the amplitude and delaying the phase of leaf movement. Ethylene application restored leaf growth in -DIF conditions, and constitutive ethylene signaling mutants maintain robust leaf movement amplitudes under -DIF, indicating that ethylene signaling becomes limiting under these conditions. In response to -DIF, the phase of ethylene emission advanced 2 h, but total ethylene emission was not reduced. However, expression analysis on members of the 1-aminocyclopropane-1-carboxylic acid (ACC) synthase ethylene biosynthesis gene family showed that ACS2 activity is specifically suppressed in the petiole region under -DIF conditions. Indeed, petioles of plants under -DIF had reduced ACC content, and application of ACC to the petiole restored leaf growth patterns. Moreover, acs2 mutants displayed reduced leaf movement under +DIF, similar to wild-type plants under -DIF. In addition, we demonstrate that the photoreceptor PHYTOCHROME B restricts ethylene biosynthesis and constrains the -DIF-induced phase shift in rhythmic growth. Our findings provide a mechanistic insight into how fluctuating temperature cycles regulate plant growth.

40 CFR 86.236-94 - Engine starting and restarting.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Engine starting and restarting. 86.236... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission... New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.236-94 Engine starting and...

40 CFR 86.206-11 - Equipment required; overview.

Code of Federal Regulations, 2010 CFR

2010-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.206-11 Equipment required...

40 CFR 86.223-94 - Oxides of nitrogen analyzer calibration.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.223-94 Oxides of...

40 CFR 86.204-94 - Section numbering; construction.

Code of Federal Regulations, 2010 CFR

2010-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.204-94 Section numbering...

40 CFR 86.228-94 - Transmissions.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.228-94 Transmissions. The provisions of § 86.128...

40 CFR 86.214-94 - Analytical gases.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.214-94 Analytical gases. The provisions of § 86...

40 CFR 86.202-94 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.202-94 Definitions. The definitions in subpart A...

40 CFR 86.208-94 - Dynamometer.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.208-94 Dynamometer. (a) For testing that is...

40 CFR 86.222-94 - Carbon monoxide analyzer calibration.

Code of Federal Regulations, 2010 CFR

2010-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.222-94 Carbon monoxide...

40 CFR 86.224-94 - Carbon dioxide analyzer calibration.

Code of Federal Regulations, 2010 CFR

2010-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.224-94 Carbon dioxide...

40 CFR 86.215-94 - EPA urban dynamometer driving schedule.

Code of Federal Regulations, 2010 CFR

2010-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.215-94 EPA urban dynamometer...

40 CFR 86.205-11 - Introduction; structure of this subpart.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.205-11 Introduction...

40 CFR 86.211-94 - Exhaust gas analytical system.

Code of Federal Regulations, 2010 CFR

2010-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.211-94 Exhaust gas...

40 CFR 86.226-94 - Calibration of other equipment.

Code of Federal Regulations, 2010 CFR

2010-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.226-94 Calibration of other...

40 CFR 86.227-94 - Test procedures; overview.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.227-94 Test procedures; overview. The...

40 CFR 86.216-94 - Calibrations, frequency and overview.

Code of Federal Regulations, 2010 CFR

2010-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.216-94 Calibrations...

40 CFR 86.219-94 - CVS calibration.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.219-94 CVS calibration. The provisions of § 86.119...

40 CFR 86.242-94 - Records required.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.242-94 Records required. The provisions of § 86...

40 CFR 86.240-94 - Exhaust sample analysis.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.240-94 Exhaust sample analysis. The...

40 CFR 86.205-94 - Introduction; structure of this subpart.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.205-94 Introduction...

40 CFR 86.201-94 - General applicability.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.201-94 General applicability. (a) This...

40 CFR 63.7743 - How do I demonstrate continuous compliance with the emissions limitations that apply to me?

Code of Federal Regulations, 2010 CFR

2010-07-01

... with these requirements. (11) For each TEA cold box mold or core making line at a new or existing iron... emissions limit for PM, total metal HAP, VOHAP, or TEA in § 63.7690(a) and subsequent performance tests at...

Effects of cold temperature and ethanol content on VOC emissions from light-duty gasoline vehicles

EPA Science Inventory

Emissions of speciated volatile organic compounds (VOCs), including mobile source air toxics (MSATs), were measured in vehicle exhaust from three light-duty spark ignition vehicles operating on summer and winter grade gasoline (E0) and ethanol blended (E10 and E85) fuels. Vehicle...

40 CFR 86.236-94 - Engine starting and restarting.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 19 2013-07-01 2013-07-01 false Engine starting and restarting. 86.236... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission... New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.236-94 Engine starting and...

40 CFR 86.236-94 - Engine starting and restarting.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 18 2011-07-01 2011-07-01 false Engine starting and restarting. 86.236... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission... New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.236-94 Engine starting and...

40 CFR 86.236-94 - Engine starting and restarting.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 19 2012-07-01 2012-07-01 false Engine starting and restarting. 86.236... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission... New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.236-94 Engine starting and...

Cold atomic hydrogen in the inner galaxy

NASA Technical Reports Server (NTRS)

Dickey, J. M.; Garwood, R. W.

1986-01-01

The VLA is used to measure 21 cm absorption in directions with the absolute value of b less than 1 deg., the absolute value of 1 less than 25 deg. to probe the cool atomic gas in the inner galaxy. Abundant H I absorption is detected; typical lines are deep and narrow, sometimes blending in velocity with adjacent features. Unlike 21 cm emission not all allowed velocities are covered: large portions of the l-v diagram are optically thin. Although not similar to H I emission, the absorption shows a striking correspondence with CO emission in the inner galaxy: essentially every strong feature detected in one survey is seen in the other. The provisional conclusion is that in the inner galaxy most cool atomic gas is associated with molecular cloud complexes. There are few or no cold atomic clouds devoid of molecules in the inner galaxy, although these are common in the outer galaxy.

Signatures of photon-scalar interaction in astrophysical situations

NASA Astrophysics Data System (ADS)

Ganguly, Avijit K.; Jaiswal, Manoj K.

2018-01-01

Dimension-5 photon ( γ) scalar ( ϕ) interaction term usually appear in the Lagrangians of bosonic sector of unified theories of electromagnetism and gravity. This interaction makes the medium dichoric and induces optical activity. Considering a toy model of an ultra-cold magnetized compact star (white dwarf (WD) or neutron star (NS)), we have modeled the propagation of very low energy photons with such interaction, in the environment of these stars. Assuming synchro-curvature process as the dominant mechanism of emission in such environments, we have tried to understand the polarimetric implications of photon-scalar coupling on the produced spectrum of the same. Further more assuming the `emission-energy vs emission-altitude' relation, that is believed to hold in such ( i.e., cold magnetized WD or NS) environments, we have tried to point out the possible modifications to the radiation spectrum when the same is incorporated along with dimension-5 photon-scalar mixing operator.

Characterizing particulate matter emissions from vehicles: chassis-dynamometer tests using a High-Resolution Aerosol Mass Spectrometer

NASA Astrophysics Data System (ADS)

Collier, S.; Zhang, Q.; Forestieri, S.; Kleeman, M.; Cappa, C. D.; Kuwayama, T.

2012-12-01

During September of 2011 a suite of real-time instruments was used to sample vehicle emissions at the California Air Resources Board Haagen-Schmidt facility in El Monte, CA. A representative fleet of 8 spark ignition gasoline vehicles, a diesel passenger vehicle, a gasoline direct-injection vehicle and an ultra-low emissions vehicle were tested on a chassis dynamometer. The emissions were sampled into the facility's standard CVS tunnel and diluted to atmospherically relevant levels (5-30 μg/m3) while controlling other factors such as relative humidity or background black carbon particulate loading concentrations. An Aerodyne High Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-MS) was among the real-time instruments used and sampled vehicle emissions at 10 second time resolution in order to characterize the non-refractory organic and inorganic particulate matter (PM). PM composition and concentration were tracked throughout the cold start driving cycle which included periods of fast acceleration and high velocity cruise control, meant to recreate typical commuter driving behavior. Variations in inorganic and organic PM composition for a given vehicle throughout the driving cycle as well as for various vehicles with differing emissions loading were characterized. Differences in PM composition for a given vehicle whose emissions are being exposed to differing experimental conditions such as varying relative humidity will also be reported. In conjunction with measurements from a Multi Wavelength Photoacoustic Black Carbon Spectrometer (MWPA-BC) and real-time gas measurements from the CARB facility, we determine the real-time emission ratios of primary organic aerosols (POA) with respect to BC and common combustion gas phase pollutants and compared to different vehicle driving conditions. The results of these tests offer the vehicle emissions community a first time glimpse at the real-time behavior of vehicle PM emissions for a variety of conditions and vehicle types at atmospherically relevant conditions and without chemical interferences from other primary or secondary aerosol sources.

Characterizing CH4, CO2 and N2O emission from barn feeding Tibetan sheep in Tibetan alpine pastoral area in cold season

NASA Astrophysics Data System (ADS)

Xu, Tianwei; Zhao, Na; Hu, Linyong; Xu, Shixiao; Liu, Hongjin; Ma, Li; Zhao, Xinquan

2017-05-01

Herein, methane (CH4), carbon dioxide (CO2) and nitrous oxide (N2O) emission from different aged barn feeding Tibetan sheep were characterized using a respiration chamber in combination with gas chromatograph method in cold season of 2013. This work was based on measuring the increase of gas concentration inside respiration chamber by the means of gas chromatograph. Results indicated that diurnal CH4 emission patterns for barn feeding Tibetan sheep were driven by feeding schedule, diurnal CO2 emission patterns were relatively stable with two slight emission peaks, diurnal N2O emission patterns were driven by the variation of temperature inside chamber. Diurnal CH4 emission rates were 17.65, 19.49 and 21.06 g sheep-1 d-1 for yearling, two-year and three-year barn feeding Tibetan sheep, account for 6.15%, 5.76% and 5.45% of their daily gross energy intakes, respectively. Diurnal CO2 emission rates were 526.88, 588.43 and 640.66 g sheep-1 d-1 for yearling, two-year and three-year barn feeding Tibetan sheep, respectively. Diurnal N2O emission rates were 1.64, 1.25 and 1.05 mg sheep-1 d-1 for yearling, two-year and three-year barn feeding Tibetan sheep, respectively. Three-year barn feeding Tibetan sheep released more CO2-eq on per unit BW and BW0.75 gain basis.

In China, Students in Crowded Dormitories with a Low Ventilation Rate Have More Common Colds: Evidence for Airborne Transmission

PubMed Central

Sun, Yuexia; Wang, Zhigang; Zhang, Yufeng; Sundell, Jan

2011-01-01

Objective To test whether the incidence of common colds among college students in China is associated with ventilation rates and crowdedness in dormitories. Methods In Phase I of the study, a cross-sectional study, 3712 students living in 1569 dorm rooms in 13 buildings responded to a questionnaire about incidence and duration of common colds in the previous 12 months. In Phase II, air temperature, relative humidity and CO2 concentration were measured for 24 hours in 238 dorm rooms in 13 buildings, during both summer and winter. Out-to indoor air flow rates at night were calculated based on measured CO2 concentrations. Results In Phase I, 10% of college students reported an incidence of more than 6 common colds in the previous 12 months, and 15% reported that each infection usually lasted for more than 2 weeks. Students in 6-person dorm rooms were about 2 times as likely to have an incidence of common colds ≥6 times per year and a duration ≥2 weeks, compared to students in 3-person rooms. In Phase II, 90% of the measured dorm rooms had an out-to indoor air flow rate less than the Chinese standard of 8.3 L/s per person during the heating season. There was a dose-response relationship between out-to indoor air flow rate per person in dorm rooms and the proportion of occupants with annual common cold infections ≥6 times. A mean ventilation rate of 5 L/(s•person) in dorm buildings was associated with 5% of self reported common cold ≥6 times, compared to 35% at 1 L/(s•person). Conclusion Crowded dormitories with low out-to indoor airflow rates are associated with more respiratory infections among college students. PMID:22110607

Organic nanowire hierarchy over fabric platform for flexible cold cathode

NASA Astrophysics Data System (ADS)

Maiti, Soumen; Narayan Maiti, Uday; Pal, Shreyasi; Chattopadhyay, Kalyan Kumar

2013-11-01

Organic charge transfer (CT) complexes initiated a growing interest in modern electronic devices owing to their easy processability and unique characteristics. In this work, three-dimensional field emitters comprising metal-organic charge transfer complex nanostructures of AgTCNQ and CuTCNQ (TCNQ, 7,7,8,8-tetracyanoquinodimethane) over flexible fabric substrate are realized. Deliberate control over the reaction parameter during organic solid phase reaction leads to modification in structural parameters of the nanowires (i.e. length, diameter) as well as their arrangement atop the carbon fibers. The optimized arrays of AgTCNQ and CuTCNQ nanowires exhibit excellent field electron emission performance with very low turn-on (1.72 and 2.56 V μm-1) and threshold fields (4.21 and 6.33 V μm-1) respectively, which are comparable to those of the best organic field emitters reported to date. The underlying conducting carbon cloth with special woven-like geometry not only offers a flexible platform for nanowire growth, but also provides an additional field enhancement to ease the electron emission.

Method and apparatus for reducing cold-phase emissions by utilizing oxygen-enriched intake air

DOEpatents

Poola, Ramesh B.; Sekar, Ramanujam R.; Stork, Kevin C.

1997-01-01

An oxygen-enriched air intake control system for an internal combustion engine includes air directing apparatus to control the air flow into the intake of the engine. During normal operation of the engine, ambient air flowing from an air filter of the engine flows through the air directing apparatus into the intake of the engine. In order to decrease the amount of carbon monoxide (CO) and hydrocarbon (HC) emissions that tend to be produced by the engine during a short period of time after the engine is started, the air directing apparatus diverts for a short period of time following the start up of the engine at least a portion of the ambient air from the air filter through a secondary path. The secondary path includes a selectively permeable membrane through which the diverted portion of the ambient air flows. The selectively permeable membrane separates nitrogen and oxygen from the diverted air so that oxygen enriched air containing from about 23% to 25% oxygen by volume is supplied to the intake of the engine.

Atlantic Multidecadal Oscillation Modulates the Impacts of Arctic Sea Ice Decline

NASA Astrophysics Data System (ADS)

Li, Fei; Orsolini, Yvan J.; Wang, Huijun; Gao, Yongqi; He, Shengping

2018-03-01

The Arctic sea ice cover has been rapidly declining in the last two decades, concurrent with a shift in the Atlantic Multidecadal Oscillation (AMO) to its warm phase around 1996/1997. Here we use both observations and model simulations to investigate the modulation of the atmospheric impacts of the decreased sea ice cover in the Atlantic sector of the Arctic (AASIC) by the AMO. We find that the AASIC loss during a cold AMO phase induces increased Ural blocking activity, a southeastward-extended snowpack, and a cold continent anomaly over Eurasia in December through northerly cold air advection and moisture transport from the Arctic. The increased Ural blocking activity and more extended Eurasian snowpack strengthen the upward propagation of planetary waves over the Siberian-Pacific sector in the lower stratosphere and hence lead to a weakened stratospheric polar vortex and a negative Arctic Oscillation (AO) phase at the surface in February. However, corresponding to the AASIC loss during a warm AMO phase, one finds more widespread warming over the Arctic and a reduced snowpack over Northern Eurasia in December. The stratosphere-troposphere coupling is suppressed in early winter and no negative AO anomaly is found in February. We suggest that the cold AMO phase is important to regulate the atmospheric response to AASIC decline, and our study provides insight to the ongoing debate on the connection between the Arctic sea ice and the AO.

The 400W at 1.8K Test Facility at CEA-Grenoble

NASA Astrophysics Data System (ADS)

Roussel, P.; Girard, A.; Jager, B.; Rousset, B.; Bonnay, P.; Millet, F.; Gully, P.

2006-04-01

A new test facility with a cooling capacity respectively of 400W at 1.8K or 800W at 4.5K, is now under nominal operation in SBT (Low Temperature Department) at CEA Grenoble. It has been recently used for thermohydraulic studies of two phase superfluid helium in autumn 2004. In the near future, this test bench will allow: - to test industrial components at 1.8K (magnets, cavities of accelerators) - to continue the present studies on thermohydraulics of two phase superfluid helium - to develop and simulate new cooling loops for ITER Cryogenics, and other applications such as high Reynolds number flows This new facility consists of a cold box connected to a warm compressor station (one subatmospheric oil ring pump in series with two screw compressors). The cold box, designed by AIR LIQUIDE, comprises two centrifugal cold compressors, a cold turbine, a wet piston expander, counter flow heat exchangers and two phase separators at 4.5K and 1.8K. The new facility uses a Programmable Logic Controller (PLC) connected to a bus for the measurements. The design is modular and will allow the use of saturated fluid flow (two phase flow at 1.8K or 4.5K) or single phase fluid forced flow. Experimental results and cooling capacity in different operation modes are detailed.

Studies on densification, mechanical, micro-structural and structure–properties relationship of magnesium aluminate spinel refractory aggregates prepared from Indian magnesite

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

Ghosh, Chandrima; Ghosh, Arup; Haldar, Manas Kamal, E-mail: manashaldar@cgcri.res.in

The present work intends to study the development of magnesium aluminate spinel aggregates from Indian magnesite in a single firing stage. The raw magnesite has been evaluated in terms of chemical analysis, differential thermal analysis, thermogravimetric analysis, infrared spectroscopy, and X-ray diffraction. The experimental batch containing Indian magnesite and calcined alumina has been sintered in the temperature range of 1550 °C–1700 °C. The sintered material has been characterized in terms of physico-chemical properties like bulk density, apparent porosity, true density, relative density and thermo-mechanical/mechanical properties like hot modulus of rupture, thermal shock resistance, cold modulus of rupture and structural propertiesmore » by X-ray diffraction in terms of phase identification and evaluation of crystal structure parameters of corresponding phases by Rietveld analysis. The microstructures developed at different temperatures have been analyzed by field emission scanning electron microscope study and compositional analysis of the developed phase has been carried out by energy dispersive X-ray study. - Highlights: • The studies have been done to characterize the developed magnesium aluminate spinel. • The studies reveal correlation between refractory behavior of spinel and developed microstructures. • The studies show the values of lattice parameters of developed phases.« less

Dust in a compact, cold, high-velocity cloud: A new approach to removing foreground emission

NASA Astrophysics Data System (ADS)

Lenz, D.; Flöer, L.; Kerp, J.

2016-02-01

Context. Because isolated high-velocity clouds (HVCs) are found at great distances from the Galactic radiation field and because they have subsolar metallicities, there have been no detections of dust in these structures. A key problem in this search is the removal of foreground dust emission. Aims: Using the Effelsberg-Bonn H I Survey and the Planck far-infrared data, we investigate a bright, cold, and clumpy HVC. This cloud apparently undergoes an interaction with the ambient medium and thus has great potential to form dust. Methods: To remove the local foreground dust emission we used a regularised, generalised linear model and we show the advantages of this approach with respect to other methods. To estimate the dust emissivity of the HVC, we set up a simple Bayesian model with mildly informative priors to perform the line fit instead of an ordinary linear least-squares approach. Results: We find that the foreground can be modelled accurately and robustly with our approach and is limited mostly by the cosmic infrared background. Despite this improvement, we did not detect any significant dust emission from this promising HVC. The 3σ-equivalent upper limit to the dust emissivity is an order of magnitude below the typical values for the Galactic interstellar medium.

Infrared dust bubble CS51 and its interaction with the surrounding interstellar medium

NASA Astrophysics Data System (ADS)

Das, Swagat R.; Tej, Anandmayee; Vig, Sarita; Liu, Hong-Li; Liu, Tie; Ishwara Chandra, C. H.; Ghosh, Swarna K.

2017-12-01

A multiwavelength investigation of the southern infrared dust bubble CS51 is presented in this paper. We probe the associated ionized, cold dust, molecular and stellar components. Radio continuum emission mapped at 610 and 1300 MHz, using the Giant Metrewave Radio Telescope, India, reveals the presence of three compact emission components (A, B, and C) apart from large-scale diffuse emission within the bubble interior. Radio spectral index map shows the co-existence of thermal and non-thermal emission components. Modified blackbody fits to the thermal dust emission using Herschel Photodetector Array Camera and Spectrometer and Spectral and Photometric Imaging Receiver data is performed to generate dust temperature and column density maps. We identify five dust clumps associated with CS51 with masses and radius in the range 810-4600 M⊙ and 1.0-1.9 pc, respectively. We further construct the column density probability distribution functions of the surrounding cold dust which display the impact of ionization feedback from high-mass stars. The estimated dynamical and fragmentation time-scales indicate the possibility of collect and collapse mechanism in play at the bubble border. Molecular line emission from the Millimeter Astronomy Legacy Team 90 GHz survey is used to understand the nature of two clumps which show signatures of expansion of CS51.

Is there widespread metal contamination from in-situ bitumen extraction at Cold Lake, Alberta heavy oil field?

PubMed

Skierszkan, Elliott K; Irvine, Graham; Doyle, James R; Kimpe, Linda E; Blais, Jules M

2013-03-01

The extraction of oil sands by in-situ methods in Alberta has expanded dramatically in the past two decades and will soon overtake surface mining as the dominant bitumen production process in the province. While concerns regarding regional metal emissions from oil sand mining and bitumen upgrading have arisen, there is a lack of information on emissions from the in-situ industry alone. Here we show using lake sediment records and regionally-distributed soil samples that in the absence of bitumen upgrading and surface mining, there has been no significant metal (As, Cd, Cu, Hg, Ni, Pb, V) enrichment from the Cold Lake in-situ oil field. Sediment records demonstrate post-industrial Cd, Hg and Pb enrichment beginning in the early Twentieth Century, which has leveled off or declined since the onset of commercial in-situ bitumen production at Cold Lake in 1985. Copyright © 2013 Elsevier B.V. All rights reserved.

The Interface Structure of High-Temperature Oxidation-Resistant Aluminum-Based Coatings on Titanium Billet Surface

NASA Astrophysics Data System (ADS)

Xu, Zhefeng; Rong, Ju; Yu, Xiaohua; Kun, Meng; Zhan, Zhaolin; Wang, Xiao; Zhang, Yannan

2017-10-01

A new type of high-temperature oxidation-resistant aluminum-based coating, on a titanium billet surface, was fabricated by the cold spray method, at a high temperature of 1050°C, for 8 h, under atmospheric pressure. The microstructure of the exposed surface was analyzed via optical microscopy, the microstructure of the coating and elemental diffusion was analyzed via field emission scanning electron microscopy, and the interfacial phases were identified via x-ray diffraction. The Ti-Al binary phase diagram and Gibbs free energy of the stable phase were calculated by Thermo-calc. The results revealed that good oxidation resistant 50-μm-thick coatings were successfully obtained after 8 h at 1050°C. Two layers were obtained after the coating process: an Al2O3 oxidation layer and a TiAl3 transition layer on the Ti-based substrate. The large and brittle Al2O3 grains on the surface, which can be easily spalled off from the surface after thermal processing, protected the substrate against oxidation during processing. In addition, the thermodynamic calculation results were in good agreement with the experimental data.

Structure of cold nuclear matter at subnuclear densities by quantum molecular dynamics

NASA Astrophysics Data System (ADS)

Watanabe, Gentaro; Sato, Katsuhiko; Yasuoka, Kenji; Ebisuzaki, Toshikazu

2003-09-01

Structure of cold nuclear matter at subnuclear densities for the proton fraction x=0.5, 0.3, and 0.1 is investigated by quantum molecular dynamics (QMD) simulations. We demonstrate that the phases with slablike and rodlike nuclei, etc. can be formed dynamically from hot uniform nuclear matter without any assumptions on nuclear shape, and also systematically analyze the structure of cold matter using two-point correlation functions and Minkowski functionals. In our simulations, we also observe intermediate phases, which have complicated nuclear shapes. It has been found out that these phases can be characterized as those with negative Euler characteristic. Our result implies the existence of these kinds of phases in addition to the simple “pasta” phases in neutron star crusts and supernova inner cores. In addition, we investigate the properties of the effective QMD interaction used in the present work to examine the validity of our results. The resultant energy per nucleon ɛn of the pure neutron matter, the proton chemical μ(0)p in pure neutron matter and the nuclear surface tension Esurf are generally reasonable in comparison with other nuclear interactions.

Three-dimensional instabilities of mantle convection with multiple phase transitions

NASA Technical Reports Server (NTRS)

Honda, S.; Yuen, D. A.; Balachandar, S.; Reuteler, D.

1993-01-01

The effects of multiple phase transitions on mantle convection are investigated by numerical simulations that are based on three-dimensional models. These simulations show that cold sheets of mantle material collide at junctions, merge, and form a strong downflow that is stopped temporarily by the transition zone. The accumulated cold material gives rise to a strong gravitational instability that causes the cold mass to sink rapidly into the lower mantle. This process promotes a massive exchange between the lower and upper mantles and triggers a global instability in the adjacent plume system. This mechanism may be cyclic in nature and may be linked to the generation of superplumes.

The Production of Cold Gas Within Galaxy Outflows

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

Scannapieco, Evan

2017-03-01

I present a suite of three-dimensional simulations of the evolution of initially hot material ejected by starburst-driven galaxy outflows. The simulations are conducted in a comoving frame that moves with the material, tracking atomic/ionic cooling, Compton cooling, and dust cooling and destruction. Compton cooling is the most efficient of these processes, while the main role of atomic/ionic cooling is to enhance density inhomogeneities. Dust, on the other hand, has little effect on the outflow evolution, and is rapidly destroyed in all the simulations except for the case with the smallest mass flux. I use the results to construct a simplemore » steady-state model of the observed UV/optical emission from each outflow. The velocity profiles in this case are dominated by geometric effects, and the overall luminosities are extremely strong functions of the properties of the host system, as observed in ultra-luminous infrared galaxies (ULIRGs). Furthermore the luminosities and maximum velocities in several models are consistent with emission-line observations of ULIRGs, although the velocities are significantly greater than observed in absorption-line studies. It may be that absorption line observations of galaxy outflows probe entrained cold material at small radii, while emission-line observations probe cold material condensing from the initially hot medium at larger distances.« less

Source Apportionment of Elemental Carbon in Beijing, China: Insights from Radiocarbon and Organic Marker Measurements.

PubMed

Zhang, Yan-Lin; Schnelle-Kreis, Jürgen; Abbaszade, Gülcin; Zimmermann, Ralf; Zotter, Peter; Shen, Rong-rong; Schäfer, Klaus; Shao, Longyi; Prévôt, André S H; Szidat, Sönke

2015-07-21

Elemental carbon (EC) or black carbon (BC) in the atmosphere has a strong influence on both climate and human health. In this study, radiocarbon ((14)C) based source apportionment is used to distinguish between fossil fuel and biomass burning sources of EC isolated from aerosol filter samples collected in Beijing from June 2010 to May 2011. The (14)C results demonstrate that EC is consistently dominated by fossil-fuel combustion throughout the whole year with a mean contribution of 79% ± 6% (ranging from 70% to 91%), though EC has a higher mean and peak concentrations in the cold season. The seasonal molecular pattern of hopanes (i.e., a class of organic markers mainly emitted during the combustion of different fossil fuels) indicates that traffic-related emissions are the most important fossil source in the warm period and coal combustion emissions are significantly increased in the cold season. By combining (14)C based source apportionment results and picene (i.e., an organic marker for coal emissions) concentrations, relative contributions from coal (mainly from residential bituminous coal) and vehicle to EC in the cold period were estimated as 25 ± 4% and 50 ± 7%, respectively, whereas the coal combustion contribution was negligible or very small in the warm period.

Time-of-Day Effects on Metabolic and Clock-Related Adjustments to Cold.

PubMed

Machado, Frederico Sander Mansur; Zhang, Zhi; Su, Yan; de Goede, Paul; Jansen, Remi; Foppen, Ewout; Coimbra, Cândido Celso; Kalsbeek, Andries

2018-01-01

Daily cyclic changes in environmental conditions are key signals for anticipatory and adaptive adjustments of most living species, including mammals. Lower ambient temperature stimulates the thermogenic activity of brown adipose tissue (BAT) and skeletal muscle. Given that the molecular components of the endogenous biological clock interact with thermal and metabolic mechanisms directly involved in the defense of body temperature, the present study evaluated the differential homeostatic responses to a cold stimulus at distinct time-windows of the light/dark-cycle. Male Wistar rats were subjected to a single episode of 3 h cold ambient temperature (4°C) at one of 6 time-points starting at Zeitgeber Times 3, 7, 11, 15, 19, and 23. Metabolic rate, core body temperature, locomotor activity (LA), feeding, and drinking behaviors were recorded during control and cold conditions at each time-point. Immediately after the stimulus, rats were euthanized and both the soleus and BAT were collected for real-time PCR. During the light phase (i.e., inactive phase), cold exposure resulted in a slight hyperthermia ( p  < 0.001). Light phase cold exposure also increased metabolic rate and LA ( p  < 0.001). In addition, the prevalence of fat oxidative metabolism was attenuated during the inactive phase ( p  < 0.001). These metabolic changes were accompanied by time-of-day and tissue-specific changes in core clock gene expression, such as DBP ( p  < 0.0001) and REV-ERBα ( p  < 0.01) in the BAT and CLOCK ( p  < 0.05), PER2 ( p  < 0.05), CRY1 ( p  < 0.05), CRY2 ( p  < 0.01), and REV-ERBα ( p  < 0.05) in the soleus skeletal muscle. Moreover, genes involved in substrate oxidation and thermogenesis were affected in a time-of-day and tissue-specific manner by cold exposure. The time-of-day modulation of substrate mobilization and oxidation during cold exposure provides a clear example of the circadian modulation of physiological and metabolic responses. Interestingly, after cold exposure, time-of-day mostly affected circadian clock gene expression in the soleus muscle, despite comparable changes in LA over the light-dark-cycle. The current findings add further evidence for tissue-specific actions of the internal clock in different peripheral organs such as skeletal muscle and BAT.

40 CFR 80.45 - Complex emissions model.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) VOCW% = Percentage change in winter VOC emissions from baseline levels (8) Phase II total VOC emissions... its domain Phase I = The years 1995-1999 Phase II = Year 2000 and beyond (b) Weightings and baselines... appropriate pollutant and Phase: Table 1—Normal and Higher Emitter Weightings for Exhaust Emissions Phase I...

Comparative Study of Hardening Mechanisms During Aging of a 304 Stainless Steel Containing α'-Martensite

NASA Astrophysics Data System (ADS)

Jeong, S. W.; Kang, U. G.; Choi, J. Y.; Nam, W. J.

2012-09-01

Strain aging and hardening behaviors of a 304 stainless steel containing deformation-induced martensite were investigated by examining mechanical properties and microstructural evolution for different aging temperature and time. Introduced age hardening mechanisms of a cold rolled 304 stainless steel were the additional formation of α'-martensite, hardening of α'-martensite, and hardening of deformed austenite. The increased amount of α'-martensite at an aging temperature of 450 °C confirmed the additional formation of α'-martensite as a hardening mechanism in a cold rolled 304 stainless steel. Additionally, the increased hardness in both α'-martensite and austenite phases with aging temperature proved that hardening of both α'-martensite and austenite phases would be effective as hardening mechanisms in cold rolled and aged 304 stainless steels. The results suggested that among hardening mechanisms, hardening of an α'-martensite phase, including the diffusion of interstitial solute carbon atoms to dislocations and the precipitation of fine carbide particles would become a major hardening mechanism during aging of cold rolled 304 stainless steels.

40 CFR 600.113-08 - Fuel economy calculations for FTP, HFET, US06, SC03 and cold temperature FTP tests.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Fuel economy calculations for FTP, HFET, US06, SC03 and cold temperature FTP tests. 600.113-08 Section 600.113-08 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) ENERGY POLICY FUEL ECONOMY AND CARBON-RELATED EXHAUST EMISSIONS OF MOTOR VEHICLES Fuel Economy...

Temperature effects on particulate emissions from DPF-equipped diesel trucks operating on conventional and biodiesel fuels.

PubMed

Book, Emily K; Snow, Richard; Long, Thomas; Fang, Tiegang; Baldauf, Richard

2015-06-01

Emissions tests were conducted on two medium heavy-duty diesel trucks equipped with a particulate filter (DPF), with one vehicle using a NOx absorber and the other a selective catalytic reduction (SCR) system for control of nitrogen oxides (NOx). Both vehicles were tested with two different fuels (ultra-low-sulfur diesel [ULSD] and biodiesel [B20]) and ambient temperatures (70ºF and 20ºF), while the truck with the NOx absorber was also operated at two loads (a heavy weight and a light weight). The test procedure included three driving cycles, a cold start with low transients (CSLT), the federal heavy-duty urban dynamometer driving schedule (UDDS), and a warm start with low transients (WSLT). Particulate matter (PM) emissions were measured second-by-second using an Aethalometer for black carbon (BC) concentrations and an engine exhaust particle sizer (EEPS) for particle count measurements between 5.6 and 560 nm. The DPF/NOx absorber vehicle experienced increased BC and particle number concentrations during cold starts under cold ambient conditions, with concentrations two to three times higher than under warm starts at higher ambient temperatures. The average particle count for the UDDS showed an opposite trend, with an approximately 27% decrease when ambient temperatures decreased from 70ºF to 20ºF. This vehicle experienced decreased emissions when going from ULSD to B20. The DPF/SCR vehicle tested had much lower emissions, with many of the BC and particle number measurements below detectable limits. However, both vehicles did experience elevated emissions caused by DPF regeneration. All regeneration events occurred during the UDDS cycle. Slight increases in emissions were measured during the WSLT cycles after the regeneration. However, the day after a regeneration occurred, both vehicles showed significant increases in particle number and BC for the CSLT drive cycle, with increases from 93 to 1380% for PM number emissions compared with tests following a day with no regeneration. The use of diesel particulate filters (DPFs) on trucks is becoming more common throughout the world. Understanding how DPFs affect air pollution emissions under varying operating conditions will be critical in implementing effective air quality standards. This study evaluated particulate matter (PM) and black carbon (BC) emissions with two DPF-equipped heavy-duty diesel trucks operating on conventional fuel and a biodiesel fuel blend at varying ambient temperatures, loads, and drive cycles.

Induction of DREB2A pathway with repression of E2F, Jasmonic acid biosynthetic and photosynthesis pathways in cold acclimation specific freeze resistant wheat crown

USDA-ARS?s Scientific Manuscript database

Winter wheat lines can achieve cold acclimation (development of tolerance to freezing temperatures) and vernalization (delay in transition from vegetative to reproductive phase) in response to low non-freezing temperatures. To describe cold acclimation specific processes and pathways, we utilized co...

40 CFR 80.91 - Individual baseline determination.

Code of Federal Regulations, 2013 CFR

2013-07-01

...—6.45 Exhaust benzene emissions, complex model—33.03 mg/mile Exhaust toxics emissions, Phase I—50.67 mg/mile Exhaust toxics emissions, Phase II—104.5 mg/mile NOX emissions, Phase I—714.4 mg/mile NOX emissions, Phase II—1461. mg/mile (d) Data collection and testing requirements—(1) Minimum sampling...

40 CFR 80.91 - Individual baseline determination.

Code of Federal Regulations, 2014 CFR

2014-07-01

...—6.45 Exhaust benzene emissions, complex model—33.03 mg/mile Exhaust toxics emissions, Phase I—50.67 mg/mile Exhaust toxics emissions, Phase II—104.5 mg/mile NOX emissions, Phase I—714.4 mg/mile NOX emissions, Phase II—1461. mg/mile (d) Data collection and testing requirements—(1) Minimum sampling...

40 CFR 80.91 - Individual baseline determination.

Code of Federal Regulations, 2011 CFR

2011-07-01

...—6.45 Exhaust benzene emissions, complex model—33.03 mg/mile Exhaust toxics emissions, Phase I—50.67 mg/mile Exhaust toxics emissions, Phase II—104.5 mg/mile NOX emissions, Phase I—714.4 mg/mile NOX emissions, Phase II—1461. mg/mile (d) Data collection and testing requirements—(1) Minimum sampling...

40 CFR 80.91 - Individual baseline determination.

Code of Federal Regulations, 2010 CFR

2010-07-01

...—6.45 Exhaust benzene emissions, complex model—33.03 mg/mile Exhaust toxics emissions, Phase I—50.67 mg/mile Exhaust toxics emissions, Phase II—104.5 mg/mile NOX emissions, Phase I—714.4 mg/mile NOX emissions, Phase II—1461. mg/mile (d) Data collection and testing requirements—(1) Minimum sampling...

Cold Temperature Effects on Speciated VOC Emissions from Modern GDI Light-Duty Vehicles 1

EPA Science Inventory

In this study, speciated VOC emissions were characterized from three modern GDI light-duty vehicles. The vehicles were tested on a chassis dynamometer housed in a climate-controlled chamber at two temperatures (20 and 72 °F) using the EPA Federal Test Procedure (FTP) and a portio...

40 CFR 86.210-08 - Exhaust gas sampling system; Diesel-cycle vehicles not requiring particulate emissions measurements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Exhaust gas sampling system; Diesel... Vehicles; Cold Temperature Test Procedures § 86.210-08 Exhaust gas sampling system; Diesel-cycle vehicles not requiring particulate emissions measurements. (a) General applicability. The exhaust gas sampling...

40 CFR 86.210-08 - Exhaust gas sampling system; Diesel-cycle vehicles not requiring particulate emissions measurements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 18 2011-07-01 2011-07-01 false Exhaust gas sampling system; Diesel... Vehicles; Cold Temperature Test Procedures § 86.210-08 Exhaust gas sampling system; Diesel-cycle vehicles not requiring particulate emissions measurements. (a) General applicability. The exhaust gas sampling...

40 CFR 86.238-94-86.239-94 - [Reserved

Code of Federal Regulations, 2010 CFR

2010-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures §§ 86.238-94—86.239-94 [Reserved] ...

40 CFR 86.233-94-86.234-94 - [Reserved

Code of Federal Regulations, 2010 CFR

2010-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures §§ 86.233-94—86.234-94 [Reserved] ...

Cold Temperature and Biodiesel Fuel Effects on Speciated Emissions of Volatile Organic Compounds from Diesel Trucks

EPA Science Inventory

Speciated volatile organic compounds (VOCs) were measured in diesel exhaust from three medium heavy-duty trucks equipped with modern aftertreatment technologies. Emissions testing was conducted on a chassis dynamometer at two ambient temperatures (-6.7°C and 21.7°C) operating on ...

Climate and chemistry effects of a regional scale nuclear conflict

NASA Astrophysics Data System (ADS)

Stenke, A.; Hoyle, C. R.; Luo, B.; Rozanov, E.; Gröbner, J.; Maag, L.; Brönnimann, S.; Peter, T.

2013-05-01

Previous studies have highlighted the severity of detrimental effects for life on Earth after an assumed regionally limited nuclear war. These effects are caused by climatic, chemical and radiative changes persisting for up to one decade. However, so far only a very limited number of climate model simulations have been performed, giving rise to the question how realistic previous computations have been. This study uses the coupled chemistry climate model (CCM) SOCOL, which belongs to a different family of CCMs than previously used, to investigate the consequences of such a hypothetical nuclear conflict. In accordance with previous studies, the present work assumes a scenario of a nuclear conflict between India and Pakistan, each applying 50 warheads with an individual blasting power of 15 kt ("Hiroshima size") against the major population centers, resulting in the emission of tiny soot particles, which are generated in the firestorms expected in the aftermath of the detonations. Substantial uncertainties related to the calculation of likely soot emissions, particularly concerning assumptions of target fuel loading and targeting of weapons, have been addressed by simulating several scenarios, with soot emissions ranging from 1 to 12 Tg. Their high absorptivity with respect to solar radiation leads to a tremendous self-lofting of the soot particles into the strato- and mesosphere, where they remain for several years. Consequently, the model suggests Earth's surface temperatures to drop by several degrees Celsius due to the shielding of solar irradiance by the soot, indicating a major global cooling. In addition, there is a substantial reduction of precipitation lasting 5 to 10 yr after the conflict, depending on the magnitude of the initial soot release. Extreme cold spells associated with massive sea ice formation are found during Northern Hemisphere winter, which expose the continental land masses of Northern America and Eurasia to chilling coldness. In the stratosphere, the strong heating leads to an acceleration of catalytic ozone loss and, consequently, to enhancements of UV radiation at the ground. In contrast to surface temperature and precipitation changes, which show a linear dependence to the soot burden, there is a saturation effect with respect to stratospheric ozone chemistry. Soot emissions of 5 Tg lead to an ozone column reduction of almost 50% in northern high latitudes, while emitting 12 Tg only increases ozone loss by a further 10%. In summary, this study, though using a different chemistry climate model, corroborates the previous investigations with respect to the atmospheric impacts. In addition to these persistent effects, the present study draws attention to episodically cold phases, which would likely add to the severity of human harm worldwide. The best insurance against such a catastrophic development would be the delegitimization of nuclear weapons.

Photocatalytic destruction of automobile exhaust emissions

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

Kaviranta, P.D.; Peden, C.H.F.

1996-10-01

Hydrocarbons, carbon monoxide, and nitrogen oxides contained in automobile exhaust emissions are among the major atmospheric air pollutants. During the first few minutes of a cold start of the engine, the emission levels of unburned hydrocarbon and CO pollutants are very high due to the inefficiency of the cold engine and the poor activity of the catalysts lower temperatures. Therefore, it is necessary to provide an alternative approach to deal with this specific problem in order to meet near-term regulatory requirements. Our approach has been to use known photocatalytic reactions obtainable on semiconducting powders such as titanium dioxide. In thismore » presentation we describe our recent studies aimed at the photocatalytic reduction of unburned hydrocarbons and carbon monoxide in automobile exhaust emissions. Our results demonstrate the effective destruction of propylene into water and carbon dioxide. The conversion was found to be dependent on the propylene flow rate. The reaction rate was studied as a function of time, humidity and temperature. The effect of the power of the UV source on conversion will also be presented.« less

Microwave plasma chemical synthesis of nanocrystalline carbon film structures and study their properties

NASA Astrophysics Data System (ADS)

Bushuev, N.; Yafarov, R.; Timoshenkov, V.; Orlov, S.; Starykh, D.

2015-08-01

The self-organization effect of diamond nanocrystals in polymer-graphite and carbon films is detected. The carbon materials deposition was carried from ethanol vapors out at low pressure using a highly non-equilibrium microwave plasma. Deposition processes of carbon film structures (diamond, graphite, graphene) is defined. Deposition processes of nanocrystalline structures containing diamond and graphite phases in different volume ratios is identified. The solid film was obtained under different conditions of microwave plasma chemical synthesis. We investigated the electrical properties of the nanocrystalline carbon films and identified it's from various factors. Influence of diamond-graphite film deposition mode in non-equilibrium microwave plasma at low pressure on emission characteristics was established. This effect is justified using the cluster model of the structure of amorphous carbon. It was shown that the reduction of bound hydrogen in carbon structures leads to a decrease in the threshold electric field of emission from 20-30 V/m to 5 V/m. Reducing the operating voltage field emission can improve mechanical stability of the synthesized film diamond-graphite emitters. Current density emission at least 20 A/cm2 was obtained. Nanocrystalline carbon film materials can be used to create a variety of functional elements in micro- and nanoelectronics and photonics such as cold electron source for emission in vacuum devices, photonic devices, cathodoluminescent flat display, highly efficient white light sources. The obtained graphene carbon net structure (with a net size about 6 μm) may be used for the manufacture of large-area transparent electrode for solar cells and cathodoluminescent light sources

FIRST CONNECTION BETWEEN COLD GAS IN EMISSION AND ABSORPTION: CO EMISSION FROM A GALAXY–QUASAR PAIR

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

Neeleman, Marcel; Prochaska, J. Xavier; Zwaan, Martin A.

2016-04-01

We present the first detection of molecular emission from a galaxy selected to be near a projected background quasar using the Atacama Large Millimeter/submillimeter Array (ALMA). The ALMA detection of CO(1−0) emission from the z = 0.101 galaxy toward quasar PKS 0439–433 is coincident with its stellar disk and yields a molecular gas mass of M{sub mol} ≈ 4.2 × 10{sup 9} M{sub ⊙} (for a Galactic CO-to-H{sub 2} conversion factor), larger than the upper limit on its atomic gas mass. We resolve the CO velocity field, obtaining a rotational velocity of 134 ± 11 km s{sup −1} and a resultant dynamical mass of ≥4 × 10{sup 10} M{sub ⊙}.more » Despite its high metallicity and large molecular mass, the z = 0.101 galaxy has a low star formation rate, implying a large gas consumption timescale, larger than that typical of late-type galaxies. Most of the molecular gas is hence likely to be in a diffuse extended phase, rather than in dense molecular clouds. By combining the results of emission and absorption studies, we find that the strongest molecular absorption component toward the quasar cannot arise from the molecular disk, but is likely to arise from diffuse gas in the galaxy’s circumgalactic medium. Our results emphasize the potential of combining molecular and stellar emission line studies with optical absorption line studies to achieve a more complete picture of the gas within and surrounding high-redshift galaxies.« less

Interstellar PAH in the Laboratory and in Space. What have we Learned from the New Generation of Laboratory and Observational Studies?

NASA Technical Reports Server (NTRS)

Salama, Farid

2005-01-01

Polycyclic Aromatic Hydrocarbons (PAHs) are an important and ubiquitous component of carbon-bearing materials in space. PAHs are the best-known candidates to account for the IR emission bands (UIR bands) and PAH spectral features are now being used as new probes of the ISM. PAHs are also thought to be among the carriers of the diffuse interstellar absorption bands (DIBs). In the model dealing with the interstellar spectral features, PAHs are present as a mixture of radicals, ions and neutral species. PAH ionization states reflect the ionization balance of the medium while PAH size, composition, and structure reflect the energetic and chemical history of the medium. A major challenge for laboratory astrophysics is to reproduce (in a realistic way) the physical conditions that exist in the emission and/or absorption interstellar zones. An extensive laboratory program has been developed at NASA Ames to assess the physical and chemical properties of PAHs in such environments and to describe how they influence the radiation and energy balance in space and the interstellar chemistry. In particular, laboratory experiments provide measurements of the spectral characteristics of interstellar PAH analogs from the ultraviolet and visible range to the infrared range for comparison with astronomical data. This paper will focus on the recent progress made in the laboratory to measure the direct absorption spectra of neutral and ionized PAHs in the gas phase in the near-UV and visible range in astrophysically relevant environments. These measurements provide data on PAHs and nanometer-sized particles that can now be directly compared to astronomical observations. The harsh physical conditions of the IS medium - characterized by a low temperature, an absence of collisions and strong VUV radiation fields - are simulated in the laboratory by associating a molecular beam with an ionizing discharge to generate a cold plasma expansion. PAH ions are formed from the neutral precursors in an isolated environment at low temperature (of the order of 100 K). The spectra of neutral and ionized PAHs are measured using the high sensitivity methods of cavity ring down spectroscopy (CRDS). These experiments provide unique information on the spectra of free, cold large carbon molecules and ions in the gas phase. Intrinsic band profiles and band positions of cold gas-phase PAHs can now be measured with high-sensitivity spectroscopy and directly compared to the astronomical data. The electronic bands measured for ionized PAH are found to be intrinsically broad (about 20 cm(sup -1)) while the bands associated with the neutral precursors are narrower (of the order of 2 - 10 cm(sup -1)). The laboratory data are discussed and compared with recent astronomical spectra of large and narrow DIBs and with the spectra of circumstellar environments of selected carbon stars and the implications for the interstellar PAH population are derived. Preliminary results also show that carbon nanoparticles are formed during the short residence time of the precursors in the plasma.

THE 1.1 mm CONTINUUM SURVEY OF THE SMALL MAGELLANIC CLOUD: PHYSICAL PROPERTIES AND EVOLUTION OF THE DUST-SELECTED CLOUDS

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

Takekoshi, Tatsuya; Minamidani, Tetsuhiro; Sorai, Kazuo

The first 1.1 mm continuum survey toward the Small Magellanic Cloud (SMC) was performed using the AzTEC instrument installed on the ASTE 10 m telescope. This survey covered 4.5 deg{sup 2} of the SMC with 1 σ noise levels of 5–12 mJy beam{sup −1}, and 44 extended objects were identified. The 1.1 mm extended emission has good spatial correlation with Herschel 160 μ m, indicating that the origin of the 1.1 mm extended emission is thermal emission from a cold dust component. We estimated physical properties using the 1.1 mm and filtered Herschel data (100, 160, 250, 350, and 500more » μ m). The 1.1 mm objects show dust temperatures of 17–45 K and gas masses of 4 × 10{sup 3}–3 × 10{sup 5} M {sub ⊙}, assuming single-temperature thermal emission from the cold dust with an emissivity index, β , of 1.2 and a gas-to-dust ratio of 1000. These physical properties are very similar to those of giant molecular clouds (GMCs) in our galaxy and the Large Magellanic Cloud. The 1.1 mm objects also displayed good spatial correlation with the Spitzer 24 μ m and CO emission, suggesting that the 1.1 mm objects trace the dense gas regions as sites of massive star formation. The dust temperature of the 1.1 mm objects also demonstrated good correlation with the 24 μ m flux connected to massive star formation. This supports the hypothesis that the heating source of the cold dust is mainly local star-formation activity in the 1.1 mm objects. The classification of the 1.1 mm objects based on the existence of star-formation activity reveals the differences in the dust temperature, gas mass, and radius, which reflects the evolution sequence of GMCs.« less

The 1.1 mm Continuum Survey of the Small Magellanic Cloud: Physical Properties and Evolution of the Dust-selected Clouds

NASA Astrophysics Data System (ADS)

Takekoshi, Tatsuya; Minamidani, Tetsuhiro; Komugi, Shinya; Kohno, Kotaro; Tosaki, Tomoka; Sorai, Kazuo; Muller, Erik; Mizuno, Norikazu; Kawamura, Akiko; Onishi, Toshikazu; Fukui, Yasuo; Ezawa, Hajime; Oshima, Tai; Scott, Kimberly S.; Austermann, Jason E.; Matsuo, Hiroshi; Aretxaga, Itziar; Hughes, David H.; Kawabe, Ryohei; Wilson, Grant W.; Yun, Min S.

2017-01-01

The first 1.1 mm continuum survey toward the Small Magellanic Cloud (SMC) was performed using the AzTEC instrument installed on the ASTE 10 m telescope. This survey covered 4.5 deg2 of the SMC with 1σ noise levels of 5-12 mJy beam-1, and 44 extended objects were identified. The 1.1 mm extended emission has good spatial correlation with Herschel 160 μm, indicating that the origin of the 1.1 mm extended emission is thermal emission from a cold dust component. We estimated physical properties using the 1.1 mm and filtered Herschel data (100, 160, 250, 350, and 500 μm). The 1.1 mm objects show dust temperatures of 17-45 K and gas masses of 4 × 103-3 × 105 M⊙, assuming single-temperature thermal emission from the cold dust with an emissivity index, β, of 1.2 and a gas-to-dust ratio of 1000. These physical properties are very similar to those of giant molecular clouds (GMCs) in our galaxy and the Large Magellanic Cloud. The 1.1 mm objects also displayed good spatial correlation with the Spitzer 24 μm and CO emission, suggesting that the 1.1 mm objects trace the dense gas regions as sites of massive star formation. The dust temperature of the 1.1 mm objects also demonstrated good correlation with the 24 μm flux connected to massive star formation. This supports the hypothesis that the heating source of the cold dust is mainly local star-formation activity in the 1.1 mm objects. The classification of the 1.1 mm objects based on the existence of star-formation activity reveals the differences in the dust temperature, gas mass, and radius, which reflects the evolution sequence of GMCs. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

Cerebral responses and role of the prefrontal cortex in conditioned pain modulation: an fMRI study in healthy subjects

PubMed Central

Bogdanov, Volodymyr B.; Viganò, Alessandro; Noirhomme, Quentin; Bogdanova, Olena V.; Guy, Nathalie; Laureys, Steven; Renshaw, Perry F.; Dallel, Radhouane; Phillips, Christophe; Schoenen, Jean

2017-01-01

The mechanisms underlying conditioned pain modulation (CPM) are multifaceted. We searched for a link between individual differences in prefrontal cortex activity during multi-trial heterotopic noxious cold conditioning and modulation of the cerebral response to phasic heat pain. In 24 healthy female subjects, we conditioned laser heat stimuli to the left hand by applying alternatively ice-cold or lukewarm compresses to the right foot. We compared pain ratings with cerebral fMRI BOLD responses. We also analyzed the relation between CPM and BOLD changes produced by the heterotopic cold conditioning itself, as well as the impact of anxiety and habituation of cold-pain ratings. Specific cerebral activation was identified in precuneus and left posterior insula/SII, respectively, during early and sustained phases of cold application. During cold conditioning, laser pain decreased (n = 7), increased (n = 10) or stayed unchanged (n = 7). At the individual level, the psychophysical effect was directly proportional to the cold-induced modulation of the laser-induced BOLD response in left posterior insula/SII. The latter correlated with the BOLD response recorded 80 s earlier during the initial 10-s phase of cold application in anterior cingulate, orbitofrontal and lateral prefrontal cortices. High anxiety and habituation of cold pain were associated with greater laser heat-induced pain during heterotopic cold stimulation. The habituation was also linked to the early cold-induced orbitofrontal responses. We conclude that individual differences in conditioned pain modulation are related to different levels of prefrontal cortical activation by the early part of the conditioning stimulus, possibly due to different levels in trait anxiety. PMID:25461267

Formation and Destruction Processes of Interstellar Dust: From Organic Molecules to carbonaceous Grains

NASA Technical Reports Server (NTRS)

Salama, F.; Biennier, L.

2004-01-01

The study of the formation and destruction processes of cosmic dust is essential to understand and to quantify the budget of extraterrestrial organic molecules. interstellar dust presents a continuous size distribution from large molecules, radicals and ions to nanometer-sized particles to micron-sized grains. The lower end of the dust size distribution is thought to be responsible for the ubiquitous spectral features that are seen in emission in the IR (UIBs) and in absorption in the visible (DIBs). The higher end of the dust-size distribution is thought to be responsible for the continuum emission plateau that is seen in the IR and for the strong absorption seen in the interstellar UV extinction curve. All these spectral signatures are characteristic of cosmic organic materials that are ubiquitous and present in various forms from gas-phase molecules to solid-state grains. Although dust with all its components plays an important role in the evolution of interstellar chemistry and in the formation of organic molecules, little is known on the formation and destruction processes of dust. Recent space observations in the UV (HST) and in the IR (ISO) help place size constraints on the molecular component of carbonaceous IS dust and indicate that small (ie., subnanometer) PAHs cannot contribute significantly to the IS features in the UV and in the IR. Studies of large molecular and nano-sized IS dust analogs formed from PAH precursors have been performed in our laboratory under conditions that simulate diffuse ISM environments (the particles are cold -100 K vibrational energy, isolated in the gas phase and exposed to a high-energy discharge environment in a cold plasma). The species (molecules, molecular fragments, ions, nanoparticles, etc) formed in the pulsed discharge nozzle (PDN) plasma source are detected with a high-sensitivity cavity ring-down spectrometer (CRDS). We will present new experimental results that indicate that nanoparticles are generated in the plasma. From these unique measurements, we derive information on the nature, the size and the structure of interstellar dust particles, the growth and the destruction processes of IS dust and the resulting budget of extraterrestrial organic molecules.

Fast and optimized methodology to generate road traffic emission inventories and their uncertainties

NASA Astrophysics Data System (ADS)

Blond, N.; Ho, B. Q.; Clappier, A.

2012-04-01

Road traffic emissions are one of the main sources of air pollution in the cities. They are also the main sources of uncertainties in the air quality numerical models used to forecast and define abatement strategies. Until now, the available models for generating road traffic emission always required a big effort, money and time. This inhibits decisions to preserve air quality, especially in developing countries where road traffic emissions are changing very fast. In this research, we developed a new model designed to fast produce road traffic emission inventories. This model, called EMISENS, combines the well-known top-down and bottom-up approaches to force them to be coherent. A Monte Carlo methodology is included for computing emission uncertainties and the uncertainty rate due to each input parameters. This paper presents the EMISENS model and a demonstration of its capabilities through an application over Strasbourg region (Alsace), France. Same input data as collected for Circul'air model (using bottom-up approach) which has been applied for many years to forecast and study air pollution by the Alsatian air quality agency, ASPA, are used to evaluate the impact of several simplifications that a user could operate . These experiments give the possibility to review older methodologies and evaluate EMISENS results when few input data are available to produce emission inventories, as in developing countries and assumptions need to be done. We show that same average fraction of mileage driven with a cold engine can be used for all the cells of the study domain and one emission factor could replace both cold and hot emission factors.

Dynamic light scattering study on phase separation of a protein-water mixture: Application on cold cataract development in the ocular lens

NASA Astrophysics Data System (ADS)

Petta, V.; Pharmakakis, N.; Papatheodorou, G. N.; Yannopoulos, S. N.

2008-06-01

We present a detailed dynamic light scattering study of the phase separation in the ocular lens emerging during cold cataract development. Cold cataract is a phase separation effect that proceeds via spinodal decomposition of the lens cytoplasm with cooling. The intensity autocorrelation functions of the lens protein content are analyzed with the aid of two methods, providing information on the populations and dynamics of the scattering elements associated with cold cataract. It is found that the temperature dependence of many measurable parameters changes appreciably at the characteristic temperature ˜16±1°C which is associated with the onset of cold cataract. By extending the temperature range of this work to previously inaccessible regimes, i.e., well below the phase separation or coexistence curve at Tcc , we have been able to accurately determine the temperature dependence of the collective and self-diffusion coefficients of proteins near the spinodal. The analysis showed that the dynamics of proteins bears some resemblance to the dynamics of structural glasses, where the apparent activation energy for particle diffusion increases below Tcc , indicating a highly cooperative motion. Application of ideas developed for studying the critical dynamics of binary protein-solvent mixtures, as well as the use of a modified Arrhenius equation, enabled us to estimate the spinodal temperature Tsp of the lens nucleus. The applicability of dynamic light scattering as a noninvasive, early-diagnostic tool for ocular diseases is also demonstrated in light of the findings of the present paper.

Automotive fuel economy and emissions program

NASA Technical Reports Server (NTRS)

Dowdy, M. W.; Baisley, R. L.

1978-01-01

Experimental data were generated to support an assessment of the relationship between automobile fuel economy and emissions control systems. Tests were made at both the engine and vehicle levels. Detailed investigations were made on cold-start emissions devices, exhaust gas recirculation systems, and air injection reactor systems. Based on the results of engine tests, an alternative emission control system and modified control strategy were implemented and tested in the vehicle. With the same fuel economy and NOx emissions as the stock vehicle, the modified vehicle reduced HC and CO emissions by about 20 percent. By removing the NOx emissions constraint, the modified vehicle demonstrated about 12 percent better fuel economy than the stock vehicle.

Low-macroscopic field emission properties of wide bandgap copper aluminium oxide nanoparticles for low-power panel applications.

PubMed

Banerjee, Arghya Narayan; Joo, Sang W

2011-09-07

Field emission properties of CuAlO(2) nanoparticles are reported for the first time, with a low turn-on field of approximately 2 V µm(-1) and field enhancement factor around 230. The field emission process follows the standard Fowler-Nordheim tunnelling of cold electron emission. The emission mechanism is found to be a combination of low electron affinity, internal nanostructure and large field enhancement at the low-dimensional emitter tips of the nanoparticles. The field emission properties are comparable to the conventional carbon-based field emitters, and thus can become alternative candidate for field emission devices for low-power panel applications.

Low-macroscopic field emission properties of wide bandgap copper aluminium oxide nanoparticles for low-power panel applications

NASA Astrophysics Data System (ADS)

Narayan Banerjee, Arghya; Joo, Sang W.

2011-09-01

Field emission properties of CuAlO2 nanoparticles are reported for the first time, with a low turn-on field of approximately 2 V µm - 1 and field enhancement factor around 230. The field emission process follows the standard Fowler-Nordheim tunnelling of cold electron emission. The emission mechanism is found to be a combination of low electron affinity, internal nanostructure and large field enhancement at the low-dimensional emitter tips of the nanoparticles. The field emission properties are comparable to the conventional carbon-based field emitters, and thus can become alternative candidate for field emission devices for low-power panel applications.

The gas phase emitter effect of lanthanum within ceramic metal halide lamps and its dependence on the La vapor pressure and operating frequency

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

Ruhrmann, C.; Hoebing, T.; Bergner, A.

2015-08-07

The gas phase emitter effect increases the lamp lifetime by lowering the work function and, with it, the temperature of the tungsten electrodes of metal halide lamps especially for lamps in ceramic vessels due to their high rare earth pressures. It is generated by a monolayer on the electrode surface of electropositive atoms of certain emitter elements, which are inserted into the lamp bulb by metal iodide salts. They are vaporized, dissociated, ionized, and deposited by an emitter ion current onto the electrode surface within the cathodic phase of lamp operation with a switched-dc or ac-current. The gas phase emittermore » effect of La and the influence of Na on the emitter effect of La are studied by spatially and phase-resolved pyrometric measurements of the electrode tip temperature, La atom, and ion densities by optical emission spectroscopy as well as optical broadband absorption spectroscopy and arc attachment images by short time photography. An addition of Na to the lamp filling increases the La vapor pressure within the lamp considerably, resulting in an improved gas phase emitter effect of La. Furthermore, the La vapor pressure is raised by a heating of the cold spot. In this way, conditions depending on the La vapor pressure and operating frequency are identified, at which the temperature of the electrodes becomes a minimum.« less

Hollow - cathode electrode for high-power, high-pressure discharge devices

DOEpatents

Chang, Jim J.; Alger, Terry W.

1995-01-01

Several different cold cathode configurations for a gas discharge device each having a plurality of grooves of selected spacing, depth and width to improve the emission of electrons in a gas discharge device. Each of the cold cathode configurations can be machined from a single piece of a selected material. Several of the configurations can be assembled with individual elements which is easily seen from the various figures.

Projections of Seasonal Patterns in Temperature- Related Deaths for Manhattan, New York

NASA Technical Reports Server (NTRS)

Li, Tiantian; Horton, Radley M.; Kinney, Patrick L.

2013-01-01

Global average temperatures have been rising for the past half-century, and the warming trend has accelerated in recent decades. Further warming is expected over the next few decades, with significant regional variations. These warming trends will probably result in more frequent, intense and persistent periods of hot temperatures in summer, and generally higher temperatures in winter. Daily death counts in cities increase markedly when temperatures reach levels that are very high relative to what is normal in a given location. Relatively cold temperatures also seem to carry risk. Rising temperatures may result in more heat-related mortality but may also reduce cold-related mortality, and the net impact on annual mortality remains uncertain. Here we use 16 downscaled global climate models and two emissions scenarios to estimate present and future seasonal patterns in temperature-related mortality in Manhattan, New York. All 32 projections yielded warm-season increases and cold-season decreases in temperature-related mortality, with positive net annual temperature-related deaths in all cases. Monthly analyses showed that the largest percentage increases may occur in May and September. These results suggest that, over a range of models and scenarios of future greenhouse gas emissions, increases in heat-related mortality could outweigh reductions in cold-related mortality, with shifting seasonal patterns.

Dilute Oxygen Combustion Phase IV Final Report

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

Riley, M.F.

2003-04-30

Novel furnace designs based on Dilute Oxygen Combustion (DOC) technology were developed under subcontract by Techint Technologies, Coraopolis, PA, to fully exploit the energy and environmental capabilities of DOC technology and to provide a competitive offering for new furnace construction opportunities. Capital cost, fuel, oxygen and utility costs, NOx emissions, oxide scaling performance, and maintenance requirements were compared for five DOC-based designs and three conventional air5-fired designs using a 10-year net present value calculation. A furnace direct completely with DOC burners offers low capital cost, low fuel rate, and minimal NOx emissions. However, these benefits do not offset the costmore » of oxygen and a full DOC-fired furnace is projected to cost $1.30 per ton more to operate than a conventional air-fired furnace. The incremental cost of the improved NOx performance is roughly $6/lb NOx, compared with an estimated $3/lb. NOx for equ8pping a conventional furnace with selective catalytic reduction (SCCR) technology. A furnace fired with DOC burners in the heating zone and ambient temperature (cold) air-fired burners in the soak zone offers low capital cost with less oxygen consumption. However, the improvement in fuel rate is not as great as the full DOC-fired design, and the DOC-cold soak design is also projected to cost $1.30 per ton more to operate than a conventional air-fired furnace. The NOx improvement with the DOC-cold soak design is also not as great as the full DOC fired design, and the incremental cost of the improved NOx performance is nearly $9/lb NOx. These results indicate that a DOC-based furnace design will not be generally competitive with conventional technology for new furnace construction under current market conditions. Fuel prices of $7/MMBtu or oxygen prices of $23/ton are needed to make the DOC furnace economics favorable. Niche applications may exist, particularly where access to capital is limited or floor space limitations are critical. DOC technology will continue to have a highly competitive role in retrofit applications requiring increases in furnace productivity.« less

Robust changes in the socio-climate risk over CONUS by mid 21st century

NASA Astrophysics Data System (ADS)

Ashfaq, M.; Rastogi, D.; Batibeniz, F.; Alifa, M.; Pagán, B. R.; Bonds, B. W.; Pal, J. S.; Diffenbaugh, N. S.; Preston, B. L.

2017-12-01

Using high-resolution near-term ensemble projections of hydro-climatic changes, we investigate impacts of climate change on natural and human systems across the CONUS. Climate projections are based a hybrid downscaling approach where a combination of regional and hydrological models are used to downscales 11 Global Climate Models from the 5th phase of Coupled Model Inter-comparison Project to 4km horizontal grid spacing for 41 years in the historical period (1965-2005) and 41 years in the near-term future period (2010-2050) under Representative Concentration Pathway 8.5. Should emissions continue to rise, climatic changes will likely intensify the regional hydrological cycle over CONUS through the acceleration of the historical trends in cold, warm and wet extremes. Our results show robust changes in the occurrence of severe weather conditions and in the likelihood of ice, freezing rain and snowstorms that may have disruptive impact on large human population across the U.S. More summer like conditions will also drive increase in cooling demands and a net increase in the energy consumption over many regions. We further use an integrated vulnerability index that combines human exposure to different climate extremes (hot, cold, wet and dry) and changes in socioeconomic pathways (due to changes in population and income levels), to reveal that future exposure to potentially damaging climatic conditions will likely increase manifold for population living in major urban centers in California, Texas, Florida, Michigan, Illinois and Northeast. With the current trajectory of emissions, these results warrant that a large human population across the U.S. may feel the impacts of climate change within its lifespan.

The TOP-SCOPE Survey of Planck Galactic Cold Clumps: Survey Overview and Results of an Exemplar Source, PGCC G26.53+0.17

NASA Astrophysics Data System (ADS)

Liu, Tie; Kim, Kee-Tae; Juvela, Mika; Wang, Ke; Tatematsu, Ken’ichi; Di Francesco, James; Liu, Sheng-Yuan; Wu, Yuefang; Thompson, Mark; Fuller, Gary; Eden, David; Li, Di; Ristorcelli, I.; Kang, Sung-ju; Lin, Yuxin; Johnstone, D.; He, J. H.; Koch, P. M.; Sanhueza, Patricio; Qin, Sheng-Li; Zhang, Q.; Hirano, N.; Goldsmith, Paul F.; Evans, Neal J., II; White, Glenn J.; Choi, Minho; Lee, Chang Won; Toth, L. V.; Mairs, Steve; Yi, H.-W.; Tang, Mengyao; Soam, Archana; Peretto, N.; Samal, Manash R.; Fich, Michel; Parsons, Harriet; Yuan, Jinghua; Zhang, Chuan-Peng; Malinen, Johanna; Bendo, George J.; Rivera-Ingraham, A.; Liu, Hong-Li; Wouterloot, Jan; Li, Pak Shing; Qian, Lei; Rawlings, Jonathan; Rawlings, Mark G.; Feng, Siyi; Aikawa, Yuri; Akhter, S.; Alina, Dana; Bell, Graham; Bernard, J.-P.; Blain, Andrew; Bőgner, Rebeka; Bronfman, L.; Byun, D.-Y.; Chapman, Scott; Chen, Huei-Ru; Chen, M.; Chen, Wen-Ping; Chen, X.; Chen, Xuepeng; Chrysostomou, A.; Cosentino, Giuliana; Cunningham, M. R.; Demyk, K.; Drabek-Maunder, Emily; Doi, Yasuo; Eswaraiah, C.; Falgarone, Edith; Fehér, O.; Fraser, Helen; Friberg, Per; Garay, G.; Ge, J. X.; Gear, W. K.; Greaves, Jane; Guan, X.; Harvey-Smith, Lisa; HASEGAWA, Tetsuo; Hatchell, J.; He, Yuxin; Henkel, C.; Hirota, T.; Holland, W.; Hughes, A.; Jarken, E.; Ji, Tae-Geun; Jimenez-Serra, Izaskun; Kang, Miju; Kawabata, Koji S.; Kim, Gwanjeong; Kim, Jungha; Kim, Jongsoo; Kim, Shinyoung; Koo, B.-C.; Kwon, Woojin; Kuan, Yi-Jehng; Lacaille, K. M.; Lai, Shih-Ping; Lee, C. F.; Lee, J.-E.; Lee, Y.-U.; Li, Dalei; Li, Hua-bai; Lo, N.; Lopez, John A. P.; Lu, Xing; Lyo, A.-Ran; Mardones, D.; Marston, A.; McGehee, P.; Meng, F.; Montier, L.; Montillaud, Julien; Moore, T.; Morata, O.; Moriarty-Schieven, Gerald H.; Ohashi, S.; Pak, Soojong; Park, Geumsook; Paladini, R.; Pattle, Kate M.; Pech, Gerardo; Pelkonen, V.-M.; Qiu, K.; Ren, Zhi-Yuan; Richer, John; Saito, M.; Sakai, Takeshi; Shang, H.; Shinnaga, Hiroko; Stamatellos, Dimitris; Tang, Y.-W.; Traficante, Alessio; Vastel, Charlotte; Viti, S.; Walsh, Andrew; Wang, Bingru; Wang, Hongchi; Wang, Junzhi; Ward-Thompson, D.; Whitworth, Anthony; Xu, Ye; Yang, J.; Yang, Yao-Lun; Yuan, Lixia; Zavagno, A.; Zhang, Guoyin; Zhang, H.-W.; Zhou, Chenlin; Zhou, Jianjun; Zhu, Lei; Zuo, Pei; Zhang, Chao

2018-02-01

The low dust temperatures (<14 K) of Planck Galactic cold clumps (PGCCs) make them ideal targets to probe the initial conditions and very early phase of star formation. “TOP-SCOPE” is a joint survey program targeting ∼2000 PGCCs in J = 1–0 transitions of CO isotopologues and ∼1000 PGCCs in 850 μm continuum emission. The objective of the “TOP-SCOPE” survey and the joint surveys (SMT 10 m, KVN 21 m, and NRO 45 m) is to statistically study the initial conditions occurring during star formation and the evolution of molecular clouds, across a wide range of environments. The observations, data analysis, and example science cases for these surveys are introduced with an exemplar source, PGCC G26.53+0.17 (G26), which is a filamentary infrared dark cloud (IRDC). The total mass, length, and mean line mass (M/L) of the G26 filament are ∼6200 M ⊙, ∼12 pc, and ∼500 M ⊙ pc‑1, respectively. Ten massive clumps, including eight starless ones, are found along the filament. The most massive clump as a whole may still be in global collapse, while its denser part seems to be undergoing expansion owing to outflow feedback. The fragmentation in the G26 filament from cloud scale to clump scale is in agreement with gravitational fragmentation of an isothermal, nonmagnetized, and turbulent supported cylinder. A bimodal behavior in dust emissivity spectral index (β) distribution is found in G26, suggesting grain growth along the filament. The G26 filament may be formed owing to large-scale compression flows evidenced by the temperature and velocity gradients across its natal cloud.

Late Pleistocene - Holocene surface processes and landscape evolution in the central Swiss Alps

NASA Astrophysics Data System (ADS)

Boxleitner, Max; Musso, Alessandra; Waroszewski, Jarosław; Malkiewicz, Małgorzata; Maisch, Max; Dahms, Dennis; Brandová, Dagmar; Christl, Marcus; de Castro Portes, Raquel; Egli, Markus

2017-10-01

The European Alps are a geomorphologically active region and experience a number of gravity-driven hillslope processes. Soil and landscape formation in the Alps has consequently undergone several minor and major traceable changes of developmental trajectories during the Holocene. Soil development is hypothesised to be often non-linear with time and characterised by stages of progressive and regressive evolution caused by upbuilding (formation, profile deepening) and erosion (profile shallowing). Several cold and warm climate phases are identified during the Holocene but it is largely unknown which effects these might have had on slope processes. By using datable moraines (10Be) and mires (14C), we have constructed a temporal framework for these processes. Using the geochemical imprint of mires in the Alpine setting of the Göschener-valley of the Central Swiss Alps, we reconstructed general (mostly erosional) landscape processes for the last ca. 10 ka. As this is the type locality for the Göschener cold phase, we assumed that this phase (Göschener cold phase I and II 1.5 and 2.5 ka BP) should have left easily recognizable traits. After deglaciation (11-12 ka BP), soil evolution was progressive. Beginning around 8 ka BP, we detect a distinct increase in erosion here, together with a vegetation change (towards tundra vegetation) and the highest measured rates of carbon sequestration. Other phases of high geomorphic activity were recognised ca. 5-6 ka BP, 4 ka BP and, to a lesser extent, 1-3 ka ago. The cold phase at 5-6 ka BP corresponds to a less distinct change in vegetation and lessened erosion. Human impact is increasingly obvious since about 2.4 ka BP which overlaps with the Göschener cold phase. Nonetheless, erosion processes were not extraordinarily high during this period and a climate effect cannot be distinguished. We detect evidence of increasing human disturbance (regressive soil evolution) for about the last 1 ka. We also detect an increase in dust flux during the last ca. 4-5 ka, presumably due to the landscape change(s) in the Sahara during this time.

Cold Water Vapor in the Barnard 5 Molecular Cloud

NASA Technical Reports Server (NTRS)

Wirstrom, E. S.; Charnley, S. B.; Persson, C. M.; Buckle, J. V.; Cordiner, M. A.; Takakuwa, S.

2014-01-01

After more than 30 yr of investigations, the nature of gas-grain interactions at low temperatures remains an unresolved issue in astrochemistry. Water ice is the dominant ice found in cold molecular clouds; however, there is only one region where cold ((is) approximately 10 K) water vapor has been detected-L1544. This study aims to shed light on ice desorption mechanisms under cold cloud conditions by expanding the sample. The clumpy distribution of methanol in dark clouds testifies to transient desorption processes at work-likely to also disrupt water ice mantles. Therefore, the Herschel HIFI instrument was used to search for cold water in a small sample of prominent methanol emission peaks. We report detections of the ground-state transition of o-H2O (J = 110-101) at 556.9360 GHz toward two positions in the cold molecular cloud, Barnard 5. The relative abundances of methanol and water gas support a desorption mechanism which disrupts the outer ice mantle layers, rather than causing complete mantle removal.

Temperature-difference-driven mass transfer through the vapor from a cold to a warm liquid.

PubMed

Struchtrup, Henning; Kjelstrup, Signe; Bedeaux, Dick

2012-06-01

Irreversible thermodynamics provides interface conditions that yield temperature and chemical potential jumps at phase boundaries. The interfacial jumps allow unexpected transport phenomena, such as the inverted temperature profile [Pao, Phys. Fluids 14, 306 (1971)] and mass transfer from a cold to a warm liquid driven by a temperature difference across the vapor phase [Mills and Phillips, Chem. Phys. Lett. 372, 615 (2002)]. Careful evaluation of the thermodynamic laws has shown [Bedeaux et al., Physica A 169, 263 (1990)] that the inverted temperature profile is observed for processes with a high heat of vaporization. In this paper, we show that cold to warm mass transfer through the vapor from a cold to a warm liquid is only possible when the heat of evaporation is sufficiently small. A necessary criterium for the size of the mass transfer coefficient is given.

Planck early results. XVII. Origin of the submillimetre excess dust emission in the Magellanic Clouds

NASA Astrophysics Data System (ADS)

Planck Collaboration; Ade, P. A. R.; Aghanim, N.; Arnaud, M.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; Balbi, A.; Banday, A. J.; Barreiro, R. B.; Bartlett, J. G.; Battaner, E.; Benabed, K.; Benoît, A.; Bernard, J.-P.; Bersanelli, M.; Bhatia, R.; Bock, J. J.; Bonaldi, A.; Bond, J. R.; Borrill, J.; Bot, C.; Bouchet, F. R.; Boulanger, F.; Bucher, M.; Burigana, C.; Cabella, P.; Cardoso, J.-F.; Catalano, A.; Cayón, L.; Challinor, A.; Chamballu, A.; Chiang, L.-Y.; Chiang, C.; Christensen, P. R.; Clements, D. L.; Colombi, S.; Couchot, F.; Coulais, A.; Crill, B. P.; Cuttaia, F.; Danese, L.; Davies, R. D.; Davis, R. J.; de Bernardis, P.; de Gasperis, G.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Delouis, J.-M.; Désert, F.-X.; Dickinson, C.; Dobashi, K.; Donzelli, S.; Doré, O.; Dörl, U.; Douspis, M.; Dupac, X.; Efstathiou, G.; Enßlin, T. A.; Finelli, F.; Forni, O.; Frailis, M.; Franceschi, E.; Fukui, Y.; Galeotta, S.; Ganga, K.; Giard, M.; Giardino, G.; Giraud-Héraud, Y.; González-Nuevo, J.; Górski, K. M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Harrison, D.; Helou, G.; Henrot-Versillé, S.; Herranz, D.; Hildebrandt, S. R.; Hivon, E.; Hobson, M.; Holmes, W. A.; Hovest, W.; Hoyland, R. J.; Huffenberger, K. M.; Jaffe, A. H.; Jones, W. C.; Juvela, M.; Kawamura, A.; Keihänen, E.; Keskitalo, R.; Kisner, T. S.; Kneissl, R.; Knox, L.; Kurki-Suonio, H.; Lagache, G.; Lähteenmäki, A.; Lamarre, J.-M.; Lasenby, A.; Laureijs, R. J.; Lawrence, C. R.; Leach, S.; Leonardi, R.; Leroy, C.; Linden-Vørnle, M.; López-Caniego, M.; Lubin, P. M.; Macías-Pérez, J. F.; MacTavish, C. J.; Madden, S.; Maffei, B.; Mandolesi, N.; Mann, R.; Maris, M.; Martínez-González, E.; Masi, S.; Matarrese, S.; Matthai, F.; Mazzotta, P.; Meinhold, P. R.; Melchiorri, A.; Mendes, L.; Mennella, A.; Miville-Deschênes, M.-A.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Munshi, D.; Murphy, A.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C. B.; Nørgaard-Nielsen, H. U.; Noviello, F.; Novikov, D.; Novikov, I.; Onishi, T.; Osborne, S.; Pajot, F.; Paladini, R.; Paradis, D.; Pasian, F.; Patanchon, G.; Perdereau, O.; Perotto, L.; Perrotta, F.; Piacentini, F.; Piat, M.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Ponthieu, N.; Poutanen, T.; Prézeau, G.; Prunet, S.; Puget, J.-L.; Reach, W. T.; Rebolo, R.; Reinecke, M.; Renault, C.; Ricciardi, S.; Riller, T.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Rowan-Robinson, M.; Rubiño-Martín, J. A.; Rusholme, B.; Sandri, M.; Savini, G.; Scott, D.; Seiffert, M. D.; Smoot, G. F.; Starck, J.-L.; Stivoli, F.; Stolyarov, V.; Sudiwala, R.; Sygnet, J.-F.; Tauber, J. A.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Torre, J.-P.; Tristram, M.; Tuovinen, J.; Umana, G.; Valenziano, L.; Varis, J.; Vielva, P.; Villa, F.; Vittorio, N.; Wade, L. A.; Wandelt, B. D.; Wilkinson, A.; Ysard, N.; Yvon, D.; Zacchei, A.; Zonca, A.

2011-12-01

The integrated spectral energy distributions (SED) of the Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC) appear significantly flatter than expected from dust models based on their far-infrared and radio emission. The still unexplained origin of this millimetre excess is investigated here using the Planck data. The integrated SED of the two galaxies before subtraction of the foreground (Milky Way) and background (CMB fluctuations) emission are in good agreement with previous determinations, confirming the presence of the millimetre excess. In the context of this preliminary analysis we do not propose a full multi-component fitting of the data, but instead subtract contributions unrelated to the galaxies and to dust emission. The background CMB contribution is subtracted using an internal linear combination (ILC) method performed locally around the galaxies. The foreground emission from the Milky Way is subtracted as a Galactic Hi template, and the dust emissivity is derived in a region surrounding the two galaxies and dominated by Milky Way emission. After subtraction, the remaining emission of both galaxies correlates closely with the atomic and molecular gas emission of the LMC and SMC. The millimetre excess in the LMC can be explained by CMB fluctuations, but a significant excess is still present in the SMC SED. The Planck and IRAS-IRIS data at 100 μm are combined to produce thermal dust temperature and optical depth maps of the two galaxies. The LMC temperature map shows the presence of a warm inner arm already found with the Spitzer data, but which also shows the existence of a previously unidentified cold outer arm. Several cold regions are found along this arm, some of which are associated with known molecular clouds. The dust optical depth maps are used to constrain the thermal dust emissivity power-law index (β). The average spectral index is found to be consistent with β = 1.5 and β = 1.2 below 500μm for the LMC and SMC respectively, significantly flatter than the values observed in the Milky Way. Also, there is evidence in the SMC of a further flattening of the SED in the sub-mm, unlike for the LMC where the SED remains consistent with β = 1.5. The spatial distribution of the millimetre dustexcess in the SMC follows the gas and thermal dust distribution. Different models are explored in order to fit the dust emission in the SMC. It is concluded that the millimetre excess is unlikely to be caused by very cold dust emission and that it could be due to a combination of spinning dust emission and thermal dust emission by more amorphous dust grains than those present in our Galaxy. Corresponding author: J.-P. Bernard, e-mail: jean-philippe.bernard@cesr.fr

Cleaner emissions from a DI diesel engine fueled with waste plastic oil derived from municipal solid waste under the influence of n-pentanol addition, cold EGR, and injection timing.

PubMed

Damodharan, Dillikannan; Sathiyagnanam, Amudhavalli Paramasivam; Rajesh Kumar, Babu; Ganesh, Kuttalam Chidambaradhanu

2018-05-01

Urban planning and development is a decisive factor that increases the automobile numbers which leads to increased energy demand across the globe. In order to meet the escalating requirements of energy, it is necessary to find viable alternatives. Waste plastic oil (WPO) is one such alternative which has dual benefits as it reduces the environmental pollution caused by plastic waste and it could possibly meet the energy requirement along with fossil fuels. The study attempted to reduce emissions from a DI diesel engine fueled with WPO using 30% by volume of n-pentanol with fossil diesel (WPO70P30). EGR (10, 20, and 30%) and injection timing modifications were made with the intention to find optimum engine operating conditions. The experimental results indicated that addition of renewable component like n-pentanol had improved the combustion characteristics by igniting WPO more homogeneously producing a higher premixed combustion phase. Smoke density for WPO70P30 was found to be twice lower than that of neat WPO at standard injection timing of 23°CA bTDC at any given EGR rate, NOx emissions were slightly on the higher side about 12% for WPO70P30 blend against WPO at same operating conditions. WPO70P30 showed lowest smoke and carbon monoxide emissions than diesel and WPO while delivering BTE's higher than WPO and closer to diesel at all EGR and injection timings. However NOx and HC emissions increased with n-pentanol addition. The use of EGR reduced NOx emissions but was found to aggravate other emissions. It was concluded WPO70P30 can be favorably used in a DI diesel engine at the engines advanced injection timing for better performance than diesel with a slight penalty in NOx emissions.

The warm and cold neutral phase in the local interstellar medium at absolute value of B greater than or equal to 10 deg

NASA Astrophysics Data System (ADS)

Poppel, W. G. L.; Marronetti, P.; Benaglia, P.

1994-07-01

We made a systematic separation of both the neutral phases using the atlases of 21-cm profiles of Heiles & Habing (1974) and Colomb et al. (1980), complemented with other data. First, we fitted the emission of the warm neutral medium (WNM) by means of a broad Gaussian curve (velocity dispersion sigma approximately 10-14 km/s). We derived maps of the column densities NWH and the radial velocities VW of the WNM. Its overall distribution appears to be very inhomogeneous with a large hole in the range b greater than or equal to +50 deg. However, if the hole is excluded, the mean latitude-profiles admit a rough cosec absolute value of b-fit common to both hemispheres. A kinematical analysis of VW for the range 10 deg less than or equal to absolute value of b less than or equal to 40 deg indicates a mean differential rotation with a small nodal deviation. At absolute value of b greater than 50 deg VW is negative, with larger values and discontinuities in the north. On the mean, sigma increases for absolute value of b decreasing, as is expected from differential rotation. From a statistical study of the peaks of the residual profiles we derived some characteristics of the cold neutral medium (CNM). The latter is generally characterized by a single component of sigma approximately 2-6 km/s. Additionally we derived the sky-distribution of the column densities NCH and the radial velocities VC of the CNM within bins of 1.2 deg sec b x 1 deg in l, b. Furthermore, we focused on the characteristics of Linblad's feature A of cool gas by considering the narrow ridge of local H I, which appears in the b-V contour maps at fixed l (e.g. Schoeber 1976). The ridge appears to be the main component of the CNM. We suggest a scenario for the formulation and evolution of the Gould belt system of stars and gas on the basis of an explosive event within a shingle of cold dense gas tilted to the galactic plane. The scenario appears to be consistent with the results found for both the neutral phases, as well as with Danly's (1989) optical and UV observations of interstellar cool gas in the lower halo.

Cold cathode emission studies on topographically modified few layer and single layer MoS2 films

NASA Astrophysics Data System (ADS)

Gaur, Anand P. S.; Sahoo, Satyaprakash; Mendoza, Frank; Rivera, Adriana M.; Kumar, Mohit; Dash, Saroj P.; Morell, Gerardo; Katiyar, Ram S.

2016-01-01

Nanostructured materials, such as carbon nanotubes, are excellent cold cathode emitters. Here, we report comparative field emission (FE) studies on topographically tailored few layer MoS2 films consisting of ⟨0001⟩ plane perpendicular (⊥) to c-axis (i.e., edge terminated vertically aligned) along with planar few layer and monolayer (1L) MoS2 films. FE measurements exhibited lower turn-on field Eto (defined as required applied electric field to emit current density of 10 μA/cm2) ˜4.5 V/μm and higher current density ˜1 mA/cm2, for edge terminated vertically aligned (ETVA) MoS2 films. However, Eto magnitude for planar few layer and 1L MoS2 films increased further to 5.7 and 11 V/μm, respectively, with one order decrease in emission current density. The observed differences in emission behavior, particularly for ETVA MoS2 is attributed to the high value of geometrical field enhancement factor (β), found to be ˜1064, resulting from the large confinement of localized electric field at edge exposed nanograins. Emission behavior of planar few layers and 1L MoS2 films are explained under a two step emission mechanism. Our studies suggest that with further tailoring the microstructure of ultra thin ETVA MoS2 films would result in elegant FE properties.

Karl G. Jansky very large array observations of cold dust and molecular gas in starbursting quasar host galaxies at z ∼ 4.5

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

Wagg, J.; Carilli, C. L.; Lentati, L.

2014-03-10

We present Karl G. Jansky Very Large Array (VLA) observations of 44 GHz continuum and CO J = 2-1 line emission in BRI 1202–0725 at z = 4.7 (a starburst galaxy and quasar pair) and BRI 1335–0417 at z = 4.4 (also hosting a quasar). With the full 8 GHz bandwidth capabilities of the upgraded VLA, we study the (rest-frame) 250 GHz thermal dust continuum emission for the first time along with the cold molecular gas traced by the low-J CO line emission. The measured CO J = 2-1 line luminosities of BRI 1202–0725 are L{sub CO}{sup ′}=(8.7±0.8)×10{sup 10} Kmore » km s{sup –1} pc{sup 2} and L{sub CO}{sup ′}=(6.0 ± 0.5)×10{sup 10} K km s{sup –1} pc{sup 2} for the submillimeter galaxy (SMG) and quasar, respectively, which are equal to previous measurements of the CO J = 5-4 line luminosities implying thermalized line emission, and we estimate a combined cold molecular gas mass of ∼9×10{sup 10} M {sub ☉}. In BRI 1335–0417 we measure L{sub CO}{sup ′}=(7.3±0.6)×10{sup 10} K km s{sup –1} pc{sup 2}. We detect continuum emission in the SMG BRI 1202–0725 North (S {sub 44} {sub GHz} = 51 ± 6 μJy), while the quasar is detected with S {sub 44} {sub GHz} = 24 ± 6 μJy and in BRI 1335–0417 we measure S {sub 44} {sub GHz} = 40 ± 7 μJy. Combining our continuum observations with previous data at (rest-frame) far-infrared and centimeter wavelengths, we fit three-component models in order to estimate the star formation rates. This spectral energy distribution fitting suggests that the dominant contribution to the observed 44 GHz continuum is thermal dust emission, while either thermal free-free or synchrotron emission contributes less than 30%.« less

Volatile transport on Venus and implications for surface geochemistry and geology

NASA Technical Reports Server (NTRS)

Brackett, Robert A.; Fegley, Bruce; Arvidson, Raymond E.

1995-01-01

The high vapor pressure of volatile metal halides and chalcogenides (e.g., of Cu, Zn, Sn, Pb, As, Sb, Bi) at typical Venus surface temperatures, coupled with the altitude-dependent temperature gradient of approximately 8.5 K/km, is calculated to transport volatile metal vapors to the highlands of Venus, where condensation and accumulation will occur. The predicted geochemistry of volatile metals on Venus is supported by observations of CuCl in volcanic gases at Kilauea and Nyiragongo, and large enrichments of these and other volatile elements in terrestrial volcanic aerosols. A one-dimensional finite difference vapor transport model shows the diffusive migration of a thickness of 0.01 to greater than 10 microns/yr of moderately to highly volatile phases (e.g., metal halides and chalcogenides) from the hot lowlands (740 K) to the cold highlands (660 K) on Venus. The diffusive transport of volatile phases on Venus may explain the observed low emissivity of the Venusian highlands, hazes at 6-km altitude observed by two Pioneer Venus entry probes, and the Pioneer Venus entry probe anomalies at 12.5 km.

El Niño-Southern Oscillation effect on quasi-biennial oscillations of temperature diurnal tides in the mesosphere and lower thermosphere

NASA Astrophysics Data System (ADS)

Sun, Yang-Yi; Liu, Huixin; Miyoshi, Yasunobu; Liu, Libo; Chang, Loren C.

2018-05-01

In this study, we evaluate the El Niño-Southern Oscillation (ENSO) signals in the two dominant temperature diurnal tides, diurnal westward wavenumber 1 (DW1) and diurnal eastward wavenumber 3 (DE3) on the quasi-biennial oscillation (QBO) scale (18-34 months) from 50 to 100 km altitudes. The tides are derived from the 21-year (January 1996-February 2017) Ground-to-Topside model of Atmosphere and Ionosphere for Aeronomy (GAIA) temperature simulations and 15-year (February 2002-February 2017) Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED)/Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) temperature observations. The results show that ENSO warm phases shorten the period ( 2 years) of the QBO in DW1 amplitude near the equator and DE3 amplitude at low latitudes of the Northern Hemisphere. In contrast, the QBO period lengthens ( 2.5 years) during the ENSO neutral and cold phases. Correlation analysis shows the long-lasting effect of ENSO on the tidal QBO in the mesosphere and lower thermosphere.[Figure not available: see fulltext.

Cold in-place recycle phase III, mix design.

DOT National Transportation Integrated Search

2014-10-01

This projects purpose is to revise the UDOT accepted design methods for Cold In-Place Recycling so that they : better reflect field behavior and target the desirable attributes of the material. The previous design process failed to : adequately pr...

X-ray flares from runaway pair production in active galactic nuclei

NASA Technical Reports Server (NTRS)

Kirk, J. G.; Mastichiadis, A.

1992-01-01

The hard X-ray spectrum of AGNs is nonthermal, probably arising from an electron-positron pair cascade, with some emission reflected off relatively cold matter. There has been interest in models on which protons are accelerated and create relativistic electrons on interaction with a local radiation field. It is shown here that a sufficient column density of protons can lead to runaway pair production: photons generated by the relativistic pairs are the targets for the protons to produce more pairs. This can produce X-ray fluxes with the characteristics observed in AGN. The model predicts the maximum ratio of luminosity to source size as well as their spectrum in the early phases. The same mechanism may also be able to create the knots of synchrotron-radiating pair plasma seen in sources such as 3C273.

PG 1316+678: A young pre-cataclysmic binary with weak reflection effects

NASA Astrophysics Data System (ADS)

Shimansky, V. V.; Borisov, N. V.; Bikmaev, I. F.; Sakhibullin, N. A.; Shimanskaya, N. N.; Spiridonova, O. I.; Irtuganov, E. N.

2013-03-01

The PG 1316+678 star is classified as a pre-cataclysmic binary, as is evidenced by its photometric and spectroscopic observations. Its orbital period is determined to be P orb = 3.3803d, which coincides with the photometric period. The intensities of the emission HI and HeI lines are shown to vary synchronously with the brightness of the object (Δ m V = 0.065 m , Δ m R = 0.08 m ). These variations arise as the UV radiation from the DAO white dwarf is reflected from the surface of the cold companion. The parameters of the binary are estimated and the time of its evolution after the common-envelope phase is determined to be t ≈ 240 000 years. Thus, PG 1316+678 is a young pre-cataclysmic NN Ser variable with the smallest known photometric reflection effect.

Effect of cold rolling on the microstructural, magnetic, mechanical, and corrosion properties of AISI 316L austenitic stainless steel

NASA Astrophysics Data System (ADS)

Tanhaei, S.; Gheisari, Kh.; Alavi Zaree, S. R.

2018-06-01

This study has evaluated the effect of different levels of cold rolling (from 0 to 50%) on the microstructural, magnetic, and mechanical properties and the corrosion behavior of 316L austenitic stainless steel in NaCl (1 mol/L) + H2SO4 (0.5 mol/L) solution. Microstructural examinations using optical microscopy revealed the development of a morphological texture from coaxial to elongated grains during the cold-rolling process. Phase analysis carried out on the basis of X-ray diffraction confirmed the formation of the ferromagnetic α'-martensite phase under the stresses applied during cold rolling. This finding is in agreement with magnetic measurements using a vibrating sample magnetometer. Mechanical properties determined by tensile and Vickers microhardness tests demonstrated an upward trend in the hardness-to-yield strength ratio with increasing cold-rolling percentage, representing a reduction in the material's work-hardening ability. Uniform and localized corrosion parameters were estimated via potentiodynamic polarization corrosion tests and electrochemical impedance spectroscopy. In contrast to the uniform corrosion, wherein the corrosion current density increased with increasing cold-working degree because of the high density of microstructural defects, the passive potential range and breakdown potential increased by cold working, showing greater resistance to pit nucleation. Although pits were formed, the cold-rolled material repassivation tendency decreased because of the broader hysteresis anodic loop, as confirmed experimentally by observation of the microscopic features after electrochemical cyclic polarization evaluations.

Chemistry and Evolution of Interstellar Clouds

NASA Technical Reports Server (NTRS)

Wooden, D. H.; Charnley, S. B.; Ehrenfreund, P.

2003-01-01

In this chapter we describe how elements have been and are still being formed in the galaxy and how they are transformed into the reservoir of materials present at the time of formation of our protosolar nebula. We discuss the global cycle of matter, beginning at its formation site in stars, where it is ejected through winds and explosions into the diffuse interstellar medium. In the next stage of the global cycle occurs in cold, dense molecular clouds, where the complexity of molecules and ices increases relative to the diffuse ISM.. When a protostar forms in a dense core within a molecular cloud, it heats the surrounding infalling matter warms and releases molecules from the solid phase into the gas phase in a warm, dense core, sponsoring a rich gas-phase chemistry. Some material from the cold and warm regions within molecular clouds probably survives as interstellar matter in the protostellar disk. For the diffuse ISM, for cold, dense clouds, and for dense-warm cores, the physio-chemical processes that occur within the gas and solid phases are discussed in detail.

Hollow-cathode electrode for high-power, high-pressure discharge devices

DOEpatents

Chang, J.J.; Alger, T.W.

1995-08-22

Several different cold cathode configurations are disclosed for a gas discharge device each having a plurality of grooves of selected spacing, depth and width to improve the emission of electrons in a gas discharge device. Each of the cold cathode configurations can be machined from a single piece of a selected material. Several of the configurations can be assembled with individual elements which is easily seen from the various figures. 8 figs.

Environmental Load during the Distribution of Cultured Tuna

NASA Astrophysics Data System (ADS)

Sakai, Rirei; Watanabe, Manabu; Suzuki, Toru

Tuna is the most favorite marine products for Japanese people. Most of them are consumed as Sashimi in Japan, and a half of them are imported. Cold transportation technology is essential to keep freshness of tuna during the oversea transportation. In the case of transporting tuna, ship transportation in ultra low temperature such as -60 °C is applied and also high speed transportation even by using airplane is practically used. On the other hand, it is a fact that such transportation processes of tuna are giving huge environmental load, though it has not been so much focused. Evaluation of cold transportation technologies from this environmental viewpoint must be important in the future. In this article, we compared CO2 emission during cold transportations of frozen tuna (marine transportation) and non-frozen tuna (air transportation) by using LCI analysis. As a result, CO2 emission of non-frozen tuna is found to be about four times greater than that of frozen tuna. This is due to the difference in the amount of freight per transportation of the airplane and the ship.

National Bio-fuel Energy Laboratory

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

Jezierski, Kelly

2010-12-27

The National Biofuel Energy Laboratory or NBEL was a consortia consisting of non-profits, universities, industry, and OEM’s. NextEnergy Center (NEC) in Detroit, Michigan was the prime with Wayne State University as the primary subcontractor. Other partners included: Art Van Furniture; Biodiesel Industries Inc. (BDI); Bosch; Clean Emission Fluids (CEF); Delphi; Oakland University; U.S. TARDEC (The Army); and later Cummins Bridgeway. The program was awarded to NextEnergy by U.S. DOE-NREL on July 1, 2005. The period of performance was about five (5) years, ending June 30, 2010. This program was executed in two phases: 1.Phase I focused on bench-scale R&D andmore » performance-property-relationships. 2.Phase II expanded those efforts into further engine testing, emissions testing, and on-road fleet testing of biodiesel using additional types of feedstock (i.e., corn, and choice white grease based). NextEnergy – a non-profit 501(c)(3) organization based in Detroit was originally awarded a $1.9 million grant from the U.S. Dept. of Energy for Phase I of the NBEL program. A few years later, NextEnergy and its partners received an additional $1.9MM in DOE funding to complete Phase II. The NBEL funding was completely exhausted by the program end date of June 30, 2010 and the cost share commitment of 20% minimum has been exceeded nearly two times over. As a result of the work performed by the NBEL consortia, the following successes were realized: 1.Over one hundred publications and presentations have been delivered by the NBEL consortia, including but not limited to: R&D efforts on algae-based biodiesel, novel heterogeneous catalysis, biodiesel properties from a vast array of feedstock blends, cold flow properties, engine testing results (several Society of Automotive Engineers [SAE] papers have been published on this research), emissions testing results, and market quality survey results. 2.One new spinoff company (NextCAT) was formed by two WSU Chemical Engineering professors and another co-founder, based on a novel heterogeneous catalyst that may be retrofitted into idled biodiesel manufacturing facilities to restart production at a greatly reduced cost. 3.Three patents have been filed by WSU and granted based on the NextCAT focus. 4.The next-generation advanced biodiesel dispensing unit (CEF F.A.S.T. unit version 2) was developed by Clean Emission Fluids (CEF). 5.NBEL aided in the preparing a sound technical basis for setting an ASTM B20 standard: ASTM Standard D7467-08 was passed in June of 2008 and officially published on October of 2008. 6.NBEL has helped to understand composition-property-performance relationships, from not only a laboratory and field testing scale, for biodiesel blends from a spectrum of feedstocks. 7.NBEL helped propel the development of biodiesel with improved performance, cetane numbers, cold flow properties, and oxidative stability. 8.Data for over 30,000 miles has been logged for the fleet testing that select members of the consortia participated in. There were five vehicles that participated in the fleet testing. Art Van provided two vehicles, one that remained idle for most of the time and one that was used often for commercial furniture deliveries, Oakland University provided one vehicle, NEC provided one vehicle, and The Night Move provided one vehicle. These vehicles were light to medium duty (2.0 to 6.6 L displacement), used B5 or B20 blends from multiple sources of feedstock (corn-, choice white grease-, and soybean-based blends) and sources (NextDiesel, BDI, or Wacker Oil), experienced a broad range in ambient temperatures (from -9 °F in Michigan winters to 93 °F in the summertime), and both city and highway driving conditions.« less

VARIATIONS BETWEEN DUST AND GAS IN THE DIFFUSE INTERSTELLAR MEDIUM. II. SEARCH FOR COLD GAS

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

Reach, William T.; Heiles, Carl; Bernard, Jean-Philippe, E-mail: wreach@sofia.usra.edu

2017-01-01

The content of interstellar clouds, in particular the inventory of diffuse molecular gas, remains uncertain. We identified a sample of isolated clouds, approximately 100 M {sub ⊙} in size, and used the dust content to estimate the total amount of gas. In Paper I, the total inferred gas content was found significantly larger than that seen in 21 cm emission measurements of H i. In this paper we test the hypothesis that the apparent excess “dark” gas is cold H i, which would be evident in absorption but not in emission due to line saturation. The results show that theremore » is not enough 21 cm absorption toward the clouds to explain the total amount of “dark” gas.« less

Optimization study of direct morphology observation by cold field emission SEM without gold coating.

PubMed

He, Dan; Fu, Cheng; Xue, Zhigang

2018-06-01

Gold coating is a general operation that is generally applied on non-conductive or low conductive materials, during which the morphology of the materials can be examined by scanning electron microscopy (SEM). However, fatal deficiencies in the materials can result in irreversible distortion and damage. The present study directly characterized different low conductive materials such as hydroxyapatite, modified poly(vinylidene fluoride) (PVDF) fiber, and zinc oxide nanopillar by cold field emission scanning electron microscopy (FE-SEM) without a gold coating. According to the characteristics of the low conductive materials, various test conditions, such as different working signal modes, accelerating voltages, electron beam spots, and working distances, were characterized to determine the best morphological observations of each sample. Copyright © 2018 Elsevier Ltd. All rights reserved.

Carbon Nanotube Bundle Array Cold Cathodes for THz Vacuum Tube Sources

NASA Astrophysics Data System (ADS)

Manohara, Harish M.; Toda, Risaku; Lin, Robert H.; Liao, Anna; Bronikowski, Michael J.; Siegel, Peter H.

2009-12-01

We present high performance cold cathodes composed of arrays of carbon nanotube bundles that routinely produce > 15 A/cm2 at applied fields of 5 to 8 V/µm without any beam focusing. They have exhibited robust operation in poor vacuums of 10-6 to 10-4 Torr- a typically achievable range inside hermetically sealed microcavities. A new double-SOI process was developed to monolithically integrate a gate and additional beam tailoring electrodes. The ability to design the electrodes for specific requirements makes carbon nanotube field emission sources extremely flexible. The lifetime of these cathodes is found to be affected by two effects: a gradual decay of emission due to anode sputtering, and catastrophic failure because of dislodging of CNT bundles at high fields ( > 10 V/µm).

Combustor for a low-emissions gas turbine engine

DOEpatents

Glezer, Boris; Greenwood, Stuart A.; Dutta, Partha; Moon, Hee-Koo

2000-01-01

Many government entities regulated emission from gas turbine engines including CO. CO production is generally reduced when CO reacts with excess oxygen at elevated temperatures to form CO2. Many manufactures use film cooling of a combustor liner adjacent to a combustion zone to increase durability of the combustion liner. Film cooling quenches reactions of CO with excess oxygen to form CO2. Cooling the combustor liner on a cold side (backside) away from the combustion zone reduces quenching. Furthermore, placing a plurality of concavities on the cold side enhances the cooling of the combustor liner. Concavities result in very little pressure reduction such that air used to cool the combustor liner may also be used in the combustion zone. An expandable combustor housing maintains a predetermined distance between the combustor housing and combustor liner.

Resolving the Large Scale Spectral Variability of the Luminous Seyfert 1 Galaxy 1H 0419-577: Evidence for a New Emission Component and Absorption by Cold Dense Matter

NASA Technical Reports Server (NTRS)

Pounds, K. A.; Reeves, J. N.; Page, K. L.; OBrien, P. T.

2004-01-01

An XMM-Newton observation of the luminous Seyfert 1 galaxy 1H 0419-577 in September 2002, when the source was in an extreme low-flux state, found a very hard X-ray spectrum at 1-10 keV with a strong soft excess below -1 keV. Comparison with an earlier XMM-Newton observation when 1H 0419-577 was X-ray bright indicated the dominant spectral variability was due to a steep power law or cool Comptonised thermal emission. Four further XMM-Newton observations, with 1H 0419-577 in intermediate flux states, now support that conclusion, while we also find the variable emission component in intermediate state difference spectra to be strongly modified by absorption in low ionisation matter. The variable soft excess then appears to be an artefact of absorption of the underlying continuum while the core soft emission can be attributed to re- combination in an extended region of more highly ionised gas. We note the wider implications of finding substantial cold dense matter overlying (or embedded in) the X-ray continuum source in a luminous Seyfert 1 galaxy.

A Modified Kinematic Model of Neutral and Ionized Gas in Galactic Center

NASA Astrophysics Data System (ADS)

Krishnarao, Dhanesh; Benjamin, Robert A.; Haffner, L. Matthew

2018-01-01

Gas near the center of the Milky Way is very complex across all phases (cold, warm, neutral, ionized, atomic, molecular, etc.) and shows strong observational evidence for warping, lopsided orientations and strongly non-circular kinematics. Historically, the kinematic complexities were modeled with many discrete features involved with expulsive phenomena near Galactic Center. However, much of the observed emission can be explained with a single unified and smooth density structure when geometrical and perspective effects are accounted for. Here we present a new model for a tilted, elliptical disk of gas within the inner 2 kpc of Galactic center based on the series of models following Burton & Liszt (1978 - 1992, Papers I- V). Machine learning techniques such as the Histogram of Oriented Gradients image correlation statistic are used to optimize the geometry and kinematics of neutral and ionized gas in 3D observational space (position,position, velocity). The model successfully predicts emission from neutral gas as seen by HI (Hi4Pi) and explains anomalous ionized gas features in H-Alpha emission (Wisconsin H-Alpha Mapper) and UV absorption lines (Hubble Space Telescope - Space Telescope Imaging Spectrograph). The modeled distribution of this tilted gas disk along with its kinematics of elliptical x1 orbits can reveal new insight about the Galactic Bar, star formation, and high-velocity gas near Galactic Center and its relation with the Fermi Bubble.

ENSO's far reaching connection to Indian cold waves.

PubMed

Ratnam, J V; Behera, Swadhin K; Annamalai, H; Ratna, Satyaban B; Rajeevan, M; Yamagata, Toshio

2016-11-23

During boreal winters, cold waves over India are primarily due to transport of cold air from higher latitudes. However, the processes associated with these cold waves are not yet clearly understood. Here by diagnosing a suite of datasets, we explore the mechanisms leading to the development and maintenance of these cold waves. Two types of cold waves are identified based on observed minimum surface temperature and statistical analysis. The first type (TYPE1), also the dominant one, depicts colder than normal temperatures covering most parts of the country while the second type (TYPE2) is more regional, with significant cold temperatures only noticeable over northwest India. Quite interestingly the first (second) type is associated with La Niña (El Niño) like conditions, suggesting that both phases of ENSO provide a favorable background for the occurrence of cold waves over India. During TYPE1 cold wave events, a low-level cyclonic anomaly generated over the Indian region as an atmospheric response to the equatorial convective anomalies is seen advecting cold temperatures into India and maintaining the cold waves. In TYPE2 cold waves, a cyclonic anomaly generated over west India anomalously brings cold winds to northwest India causing cold waves only in those parts.

Modeling of meteorology, chemistry and aerosol for the 2017 Utah Winter Fine Particle Study

NASA Astrophysics Data System (ADS)

McKeen, S. A.; Angevine, W. M.; McDonald, B.; Ahmadov, R.; Franchin, A.; Middlebrook, A. M.; Fibiger, D. L.; McDuffie, E. E.; Womack, C.; Brown, S. S.; Moravek, A.; Murphy, J. G.; Trainer, M.

2017-12-01

The Utah Winter Fine Particle Study (UWFPS-17) field project took place during January and February of 2017 within the populated region of the Great Salt Lake, Utah. The study focused on understanding the meteorology and chemistry associated with high particulate matter (PM) levels often observed near Salt Lake City during stable wintertime conditions. Detailed composition and meteorological observations were taken from the NOAA Twin-Otter aircraft and several surface sites during the study period, and extremely high aerosol conditions were encountered for two cold-pool episodes occurring in the last 2 weeks of January. A clear understanding of the photochemical and aerosol processes leading to these high PM events is still lacking. Here we present high spatiotemporal resolution simulations of meteorology, PM and chemistry over Utah from January 13 to February 1, 2017 using the WRF/Chem photochemical model. Correctly characterizing the meteorology is difficult due to the complex terrain and shallow inversion layers. We discuss the approach and limitations of the simulated meteorology, and evaluate low-level pollutant mixing using vertical profiles from missed airport approaches by the NOAA Twin-Otter performed routinely during each flight. Full photochemical simulations are calculated using NOx, ammonia and VOC emissions from the U.S. EPA NEI-2011 emissions inventory. Comparisons of the observed vertical column amounts of NOx, ammonia, aerosol nitrate and ammonium with model results shows the inventory estimates for ammonia emissions are low by a factor of four and NOx emissions are low by nearly a factor of two. The partitioning of both nitrate and NH3 between gas and particle phase depends strongly on the NH3 and NOx emissions to the model and calculated NOx to nitrate conversion rates. These rates are underestimated by gas-phase chemistry alone, even though surface snow albedo increases photolysis rates by nearly a factor of two. Several additional conversion mechanisms are added and evaluated in the model, including: heterogeneous nitrate to aerosol formation, catalytic conversion of NO2 to HONO and HNO3 at the snow surface, and direct HONO emissions from vehicles. Each mechanism contributes to the model matching observed NOx and total nitrate levels within 25% for median statistics over the study period.

Technology Application of Environmental Friendly Refrigeration (Green Refrigeration) on Cold Storage for Fishery Industry

NASA Astrophysics Data System (ADS)

Rasta, IM; Susila, IDM; Subagia, IWA

2018-01-01

The application of refrigeration technology to postharvest fishery products is an very important. Moreover, Indonesia is a tropical region with relatively high temperatures. Fish storage age can be prolonged with a decrease in temperature. Frozen fish can even be stored for several months. Fish freezing means preparing fish for storage in low-temperature cold storage. The working fluid used in cold storage to cool low-temperature chambers and throw heat into high-temperature environments is refrigerant. So far refrigerant used in cold storage is Hydrochloroflourocarbons (HCFC) that is R-22. Chlor is a gas that causes ODP (Ozone Depleting Potential), while Flour is a gas that causes GWP (Global Warming Potential). Government policy began in 2015 to implement Hydrochloroflourocarbons Phase-Out Management Plan. Hydrocarbon (HC) is an alternative substitute for R-22. HC-22 (propane ≥ 99.5%) has several advantages, among others: environmentally friendly, indicated by a zero ODP value, and GWP = 3 (negligible), thermophysical property and good heat transfer characteristics, vapor phase density Which is low, and good solubility with mineral lubricants. The use of HC-22 in cold storage is less than R-22. From the analysis results obtained, cold storage system using HC-22 has better performance and energy consumption is more efficient than the R-22.

High strength, low carbon, dual phase steel rods and wires and process for making same

DOEpatents

Thomas, Gareth; Nakagawa, Alvin H.

1986-01-01

A high strength, high ductility, low carbon, dual phase steel wire, bar or rod and process for making the same is provided. The steel wire, bar or rod is produced by cold drawing to the desired diameter in a single multipass operation a low carbon steel composition characterized by a duplex microstructure consisting essentially of a strong second phase dispersed in a soft ferrite matrix with a microstructure and morphology having sufficient cold formability to allow reductions in cross-sectional area of up to about 99.9%. Tensile strengths of at least 120 ksi to over 400 ksi may be obtained.

Comparison of chemical characteristics of 495 biomass burning plumes intercepted by the NASA DC-8 aircraft during the ARCTAS/CARB-2008 field campaign

NASA Astrophysics Data System (ADS)

Hecobian, A.; Liu, Z.; Hennigan, C. J.; Huey, L. G.; Jimenez, J. L.; Cubison, M. J.; Vay, S.; Diskin, G. S.; Sachse, G. W.; Wisthaler, A.; Mikoviny, T.; Weinheimer, A. J.; Liao, J.; Knapp, D. J.; Wennberg, P. O.; Kürten, A.; Crounse, J. D.; St. Clair, J.; Wang, Y.; Weber, R. J.

2011-12-01

This paper compares measurements of gaseous and particulate emissions from a wide range of biomass-burning plumes intercepted by the NASA DC-8 research aircraft during the three phases of the ARCTAS-2008 experiment: ARCTAS-A, based out of Fairbanks, Alaska, USA (3 April to 19 April 2008); ARCTAS-B based out of Cold Lake, Alberta, Canada (29 June to 13 July 2008); and ARCTAS-CARB, based out of Palmdale, California, USA (18 June to 24 June 2008). Approximately 500 smoke plumes from biomass burning emissions that varied in age from minutes to days were segregated by fire source region and urban emission influences. The normalized excess mixing ratios (NEMR) of gaseous (carbon dioxide, acetonitrile, hydrogen cyanide, toluene, benzene, methane, oxides of nitrogen and ozone) and fine aerosol particulate components (nitrate, sulfate, ammonium, chloride, organic aerosols and water soluble organic carbon) of these plumes were compared. A detailed statistical analysis of the different plume categories for different gaseous and aerosol species is presented in this paper. The comparison of NEMR values showed that CH4 concentrations were higher in air-masses that were influenced by urban emissions. Fresh biomass burning plumes mixed with urban emissions showed a higher degree of oxidative processing in comparison with fresh biomass burning only plumes. This was evident in higher concentrations of inorganic aerosol components such as sulfate, nitrate and ammonium, but not reflected in the organic components. Lower NOx NEMRs combined with high sulfate, nitrate and ammonium NEMRs in aerosols of plumes subject to long-range transport, when comparing all plume categories, provided evidence of advanced processing of these plumes.

Tracing the Baryon Cycle within Nearby Galaxies with a next-generation VLA

NASA Astrophysics Data System (ADS)

Kepley, Amanda A.; Leroy, Adam; Murphy, Eric J.; ngVLA Baryon Cycle Science Working Group

2017-01-01

The evolution of galaxies over cosmic time is shaped by the cycling of baryons through these systems, namely the inflow of atomic gas, the formation of molecular structures, the birth of stars, and the expulsion of gas due to associated feedback processes. The best way to study this cycle in detail are observations of nearby galaxies. These systems provide a complete picture of baryon cycling over a wide range of astrophysical conditions. In the next decade, higher resolution/sensitivity observations of such galaxies will fundamentally improve our knowledge of galaxy formation and evolution, allowing us to better interpret higher redshift observations of sources that were rapidly evolving at epochs soon after the Big Bang. In particular, the centimeter-to-millimeter part of the spectrum provides critical diagnostics for each of the key baryon cycling processes and access to almost all phases of gas in galaxies: cool and cold gas (via emission and absorption lines), ionized gas (via free-free continuum and recombination lines), cosmic rays and hot gas (via synchrotron emission and the Sunyaev-Zeldovich effect). This poster highlights a number of key science problems in this area whose solutions require a next-generation radio-mm interferometer such as the next-generation VLA.

The Upper Atmosphere Research Satellite microwave limb sounder instrument

NASA Technical Reports Server (NTRS)

Barath, F. T.; Chavez, M. C.; Cofield, R. E.; Flower, D. A.; Frerking, M. A.; Gram, M. B.; Harris, W. M.; Holden, J. R.; Jarnot, R. F.; Kloezeman, W. G.

1993-01-01

The microwave limb sounder (MLS) on the Upper Atmosphere Research Satellite (UARS) is the first satellite experiment using limb sounding techniques at microwave frequencies. Primary measurement objectives are stratospheric ClO, O3, H2O, temperature, and pressure. Measurements are of thermal emission: all are performed simultaneously and continuously and are not degraded by ice clouds or volcanic aerosols. The instrument has a 1.6-m mechanically scanning antenna system and contains heterodyne radiometers in spectral bands centred near 63, 183, and 205 GHz. The radiometers operate at ambient temperature and use Schottky-diode mixers with local oscillators derived from phase-locked Gunn oscillators. Frequency tripling by varactor multipliers generates the 183- and 205-GHz local oscillators, and quasi-optical techniques inject these into the mixers. Six 15-channel filter banks spectrally resolve stratospheric thermal emission lines and produce an output spectrum every 2 s. Thermal stability is sufficient for 'total power' measurements which do not require fast chopping. Radiometric calibration, consisting of measurements of cold space and an internal target, is performed every 65-s limb scan. Instrument in-orbit performance has been excellent, and all objectives are being met.

The Upper Atmosphere Research Satellite microwave limb sounder instrument

NASA Astrophysics Data System (ADS)

Barath, F. T.; Chavez, M. C.; Cofield, R. E.; Flower, D. A.; Frerking, M. A.; Gram, M. B.; Harris, W. M.; Holden, J. R.; Jarnot, R. F.; Kloezeman, W. G.

1993-06-01

The microwave limb sounder (MLS) on the Upper Atmosphere Research Satellite (UARS) is the first satellite experiment using limb sounding techniques at microwave frequencies. Primary measurement objectives are stratospheric ClO, O3, H2O, temperature, and pressure. Measurements are of thermal emission: all are performed simultaneously and continuously and are not degraded by ice clouds or volcanic aerosols. The instrument has a 1.6-m mechanically scanning antenna system and contains heterodyne radiometers in spectral bands centred near 63, 183, and 205 GHz. The radiometers operate at ambient temperature and use Schottky-diode mixers with local oscillators derived from phase-locked Gunn oscillators. Frequency tripling by varactor multipliers generates the 183- and 205-GHz local oscillators, and quasi-optical techniques inject these into the mixers. Six 15-channel filter banks spectrally resolve stratospheric thermal emission lines and produce an output spectrum every 2 s. Thermal stability is sufficient for 'total power' measurements which do not require fast chopping. Radiometric calibration, consisting of measurements of cold space and an internal target, is performed every 65-s limb scan. Instrument in-orbit performance has been excellent, and all objectives are being met.

Spin-orbit-coupled fermions in an optical lattice clock

NASA Astrophysics Data System (ADS)

Kolkowitz, S.; Bromley, S. L.; Bothwell, T.; Wall, M. L.; Marti, G. E.; Koller, A. P.; Zhang, X.; Rey, A. M.; Ye, J.

2017-02-01

Engineered spin-orbit coupling (SOC) in cold-atom systems can enable the study of new synthetic materials and complex condensed matter phenomena. However, spontaneous emission in alkali-atom spin-orbit-coupled systems is hindered by heating, limiting the observation of many-body effects and motivating research into potential alternatives. Here we demonstrate that spin-orbit-coupled fermions can be engineered to occur naturally in a one-dimensional optical lattice clock. In contrast to previous SOC experiments, here the SOC is both generated and probed using a direct ultra-narrow optical clock transition between two electronic orbital states in 87Sr atoms. We use clock spectroscopy to prepare lattice band populations, internal electronic states and quasi-momenta, and to produce spin-orbit-coupled dynamics. The exceptionally long lifetime of the excited clock state (160 seconds) eliminates decoherence and atom loss from spontaneous emission at all relevant experimental timescales, allowing subsequent momentum- and spin-resolved in situ probing of the SOC band structure and eigenstates. We use these capabilities to study Bloch oscillations, spin-momentum locking and Van Hove singularities in the transition density of states. Our results lay the groundwork for using fermionic optical lattice clocks to probe new phases of matter.

Herschel Observations of C+ in the Vicinity of Star Forming Complexes in the Galactic Plane

NASA Astrophysics Data System (ADS)

Pineda, Jorge; Velusamy, T.; Langer, W.; Goldsmith, P.; Li, D.; Yorke, H.

2010-05-01

The CII fine-structure line at 158 um, is an excellent tracer of the warm diffuse gas and the hot, dense Photon Dominated Regions (PDRs). We can, therefore, use the CII emission as a probe to understand the effects of star formation on their interstellar environment. Here we present the first results from the Galactic Observations of Terahertz C+ (GOT C+), a Herschel Key Project study of CII fine structure emission in the vicinity of star forming complexes. In the Priority Science Phase of HIFI observations, the GOT C+ project collects data along a dozen lines of sight passing near star forming regions in the inner Galaxy from longitude 310 degrees to 25 degrees. We discuss our first results on the transition between dense and hot gas (traced by CII) and dense and cold gas (traced by 12CO and 13CO). This research was conducted at the Jet Propulsion Laboratory, California Institute of Technology under contract with the National Aeronautics and Space Administration. JLP was supported under the NASA Postdoctoral Program at JPL, Caltech, administered by Oak Ridge Associated Universities through a contract with NASA, and is currently supported as a Caltech-JPL Postdoc.

Optical chopper for the HIRDLS instrument

NASA Astrophysics Data System (ADS)

Opyd, Walter G.; Rudolf, Wayne; Loewenthal, Stuart; Heal, Thomas

1998-11-01

Test chipper performance, as well as mechanical design and electronic control concepts, are presented for the optical chopper developed for the High-Resolution Dynamics Limb Sounder (HIRDLS) to be flown on the CHEM-1 satellite of the NASA Earth Observing System (EOS). Optical chopping is essential in order to achieve the required sensitivity and accuracy in measurement of infrared emission from various chemical species in the earth's atmosphere. Chopping of the optical input as far forward in the telescope as practical minimizes calibration errors arising from variations in emission from warm optics and due to electronic drifts in the infrared detecting system. At 500 Hz, the reflective chopper blade switches between the atmospheric limb view and reference radiation from cold space. The HIRDLS chopper is a six- toothed, mirrored wheel driven by a three-phase, permanent- magnet, brushless DC motor with trapezoidal excitation synchronized to motor back-emf. Chopper design was driven by requirements of (1) continuous operation at 5000 RPM for 50,000 hours in space vacuum, (2) chopping amplitude stability of one part in 100,000, (3) lubricant loss control for both bearing reliability and prevention of optics contamination, (4) compact size to fit in the folded telescope, and (5) survival in the launch environment.

Precipitation-induced of partial annealing of Ni-rich NiTi shape memory alloy

NASA Astrophysics Data System (ADS)

Nashrudin, Muhammad Naqib; Mahmud, Abdus Samad; Mohamad, Hishamiakim

2018-05-01

NiTi shape memory alloy behavior is very sensitive to alloy composition and heat treatment processes. Thermomechanical behavior of near-equiatomic alloy is normally enhanced by partial anneal of a cold-worked specimen. The shape memory behavior of Ni-rich alloy can be enhanced by ageing precipitation. This work studied the effect of simultaneous partial annealing and ageing precipitation of a Ni-rich cold drawn Ti-50.9at%Ni wire towards martensite phase transformation behavior. Ageing treatment of a non-cold worked specimen was also done for comparison. It was found that the increase of heat treatment temperature caused the forward transformation stress to decrease for the cold worked and non-cold worked specimens. Strain recovery on the reverse transformation of the cold worked wire improved compared to the non-cold worked wire as the temperature increased.

Control of flowering time and cold response by a NAC-domain protein in Arabidopsis.

PubMed

Yoo, So Yeon; Kim, Yunhee; Kim, Soo Young; Lee, Jong Seob; Ahn, Ji Hoon

2007-07-25

Plants must integrate complex signals from environmental and endogenous cues to fine-tune the timing of flowering. Low temperature is one of the most common environmental stresses that affect flowering time; however, molecular mechanisms underlying the cold temperature regulation of flowering time are not fully understood. We report the identification of a novel regulator, LONG VEGETATIVE PHASE 1 (LOV1), that controls flowering time and cold response. An Arabidopsis mutant, longvegetative phase 1-1D (lov1-1D) showing the late-flowering phenotype, was isolated by activation tagging screening. Subsequent analyses demonstrated that the phenotype of the mutant resulted from the overexpression of a NAC-domain protein gene (At2g02450). Both gain- and loss-of-function alleles of LOV1 affected flowering time predominantly under long-day but not short-day conditions, suggesting that LOV1 may act within the photoperiod pathway. The expression of CONSTANS (CO), a floral promoter, was affected by LOV1 level, suggesting that LOV1 controls flowering time by negatively regulating CO expression. The epistatic relationship between CO and LOV1 was consistent with this proposed regulatory pathway. Physiological analyses to elucidate upstream signalling pathways revealed that LOV1 regulates the cold response in plants. Loss of LOV1 function resulted in hypersensitivity to cold temperature, whereas a gain-of-function allele conferred cold tolerance. The freezing tolerance was accompanied by upregulation of cold response genes, COLD-REGULATED 15A (COR15A) and COLD INDUCED 1 (KIN1) without affecting expression of the C-repeat-binding factor/dehydration responsive element-binding factor 1 (CBF/DREB1) family of genes. Our study shows that LOV1 functions as a floral repressor that negatively regulates CO expression under long-day conditions and acts as a common regulator of two intersecting pathways that regulate flowering time and the cold response, respectively. Our results suggest an overlapping pathway for controlling cold stress response and flowering time in plants.

A prospective comparison of cold snare polypectomy using traditional or dedicated cold snares for the resection of small sessile colorectal polyps

PubMed Central

Dwyer, Jeremy P.; Tan, Jonathan Y. C.; Urquhart, Paul; Secomb, Robyn; Bunn, Catherine; Reynolds, John; La Nauze, Richard; Kemp, William; Roberts, Stuart; Brown, Gregor

2017-01-01

Background and study aims  The evidence for efficacy and safety of cold snare polypectomy is limited. The aim of this study was to assess the completeness of resection and safety of cold snare polypectomy, using either traditional or dedicated cold snares. Patients and methods  This was a prospective, non-randomized study performed at a single tertiary hospital. Adult patients with at least one colorectal polyp (size ≤ 10 mm) removed by cold snare were included. In the first phase, all patients had polyps removed by traditional snare without diathermy. In the second phase, all patients had polyps removed by dedicated cold snare. Complete endoscopic resection was determined from histological examination of quadrantic polypectomy margin biopsies. Immediate or delayed bleeding within 2 weeks was recorded. Results  In total, 181 patients with 299 eligible polyps (n = 93 (173 polyps) traditional snare group, n = 88 (126 polyps) dedicated cold snare group) were included. Patient demographics and procedure indications were similar between groups. Mean polyp size was 6 mm in both groups ( P  = 0.25). Complete polyp resection was 165 /173 (95.4 %; 95 %CI 90.5 – 97.6 %) in the traditional snare group and 124/126 (98.4 %; 95 %CI 93.7 – 99.6 %) in the dedicated cold snare group ( P  = 0.16). Serrated polyps, compared with adenomatous polyps, had a higher rate of incomplete resection (7 % vs. 2 %, P  = 0.03). There was no statistically significant difference in the rate of immediate bleeding (3 % vs. 1 %, P  = 0.41) and there were no delayed hemorrhages or perforations. Conclusions  Cold snare polypectomy is effective and safe for the complete endoscopic resection of small (≤ 10 mm) colorectal polyps with either traditional or dedicated cold snares. PMID:29250580

Evidence for Atmospheric Cold-trap Processes in the Noninverted Emission Spectrum of Kepler-13Ab Using HST /WFC3

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

Beatty, Thomas G.; Zhao, Ming; Gilliland, Ronald L.

We observed two eclipses of the Kepler-13A planetary system, on UT 2014 April 28 and UT 2014 October 13, in the near-infrared using Wide Field Camera 3 on the Hubble Space Telescope . By using the nearby binary stars Kepler-13BC as a reference, we were able to create a differential light curve for Kepler-13A that had little of the systematics typically present in HST /WFC3 spectrophotometry. We measure a broadband (1.1–1.65 μ m) eclipse depth of 734 ± 28 ppm and are able to measure the emission spectrum of the planet at R  ≈ 50 with an average precision of 70 ppm. Wemore » find that Kepler-13Ab possesses a noninverted, monotonically decreasing vertical temperature profile. We exclude an isothermal profile and an inverted profile at more than 3 σ . We also find that the dayside emission of Kepler-13Ab appears generally similar to an isolated M7 brown dwarf at a similar effective temperature. Due to the relatively high mass and surface gravity of Kepler-13Ab, we suggest that the apparent lack of an inversion is due to cold-trap processes in the planet’s atmosphere. Using a toy model for where cold traps should inhibit inversions, as well as observations of other planets in this temperature range with measured emission spectra, we argue that with more detailed modeling and more observations we may be able to place useful constraints on the size of condensates on the daysides of hot Jupiters.« less

Substellar fragmentation in self-gravitating fluids with a major phase transition

NASA Astrophysics Data System (ADS)

Füglistaler, A.; Pfenniger, D.

2015-06-01

Context. The observation of various ices in cold molecular clouds, the existence of ubiquitous substellar, cold H2 globules in planetary nebulae and supernova remnants, or the mere existence of comets suggest that the physics of very cold interstellar gas might be much richer than usually envisioned. At the extreme of low temperatures (≲10 K), H2 itself is subject to a phase transition crossing the entire cosmic gas density scale. Aims: This well-known, laboratory-based fact motivates us to study the ideal case of a cold neutral gaseous medium in interstellar conditions for which the bulk of the mass, instead of trace elements, is subject to a gas-liquid or gas-solid phase transition. Methods: On the one hand, the equilibrium of general non-ideal fluids is studied using the virial theorem and linear stability analysis. On the other hand, the non-linear dynamics is studied using computer simulations to characterize the expected formation of solid bodies analogous to comets. The simulations are run with a state-of-the-art molecular dynamics code (LAMMPS) using the Lennard-Jones inter-molecular potential. The long-range gravitational forces can be taken into account together with short-range molecular forces with finite limited computational resources, using super-molecules, provided the right scaling is followed. Results: The concept of super-molecule, where the phase transition conditions are preserved by the proper choice of the particle parameters, is tested with computer simulations, allowing us to correctly satisfy the Jeans instability criterion for one-phase fluids. The simulations show that fluids presenting a phase transition are gravitationally unstable as well, independent of the strength of the gravitational potential, producing two distinct kinds of substellar bodies, those dominated by gravity (planetoids) and those dominated by molecular attractive force (comets). Conclusions: Observations, formal analysis, and computer simulations suggest the possibility of the formation of substellar H2 clumps in cold molecular clouds due to the combination of phase transition and gravity. Fluids presenting a phase transition are gravitationally unstable, independent of the strength of the gravitational potential. Arbitrarily small H2 clumps may form even at relatively high temperatures up to 400-600 K, according to virial analysis. The combination of phase transition and gravity may be relevant for a wider range of astrophysical situations, such as proto-planetary disks. Figures 33-44 are available in electronic form at http://www.aanda.org

Projected temperature-related deaths in ten large U.S. metropolitan areas under different climate change scenarios.

PubMed

Weinberger, Kate R; Haykin, Leah; Eliot, Melissa N; Schwartz, Joel D; Gasparrini, Antonio; Wellenius, Gregory A

2017-10-01

There is an established U-shaped association between daily temperature and mortality. Temperature changes projected through the end of century are expected to lead to higher rates of heat-related mortality but also lower rates of cold-related mortality, such that the net change in temperature-related mortality will depend on location. We quantified the change in heat-, cold-, and temperature-related mortality rates through the end of the century across 10 large US metropolitan areas. We applied location-specific projections of future temperature from over 40 downscaled climate models to exposure-response functions relating daily temperature and mortality in 10 US metropolitan areas to estimate the change in temperature-related mortality rates in 2045-2055 and 2085-2095 compared to 1992-2002, under two greenhouse gas emissions scenarios (RCP 4.5 and 8.5). We further calculated the total number of deaths attributable to temperature in 1997, 2050, and 2090 in each metropolitan area, either assuming constant population or accounting for projected population growth. In each of the 10 metropolitan areas, projected future temperatures were associated with lower rates of cold-related deaths and higher rates of heat-related deaths. Under the higher-emission RCP 8.5 scenario, 8 of the 10 metropolitan areas are projected to experience a net increase in annual temperature-related deaths per million people by 2086-2095, ranging from a net increase of 627 (95% empirical confidence interval [eCI]: 239, 1018) deaths per million in Los Angeles to a net decrease of 59 (95% eCI: -485, 314) deaths per million in Boston. Applying these projected temperature-related mortality rates to projected population size underscores the large public health burden of temperature. Increases in the heat-related death rate are projected to outweigh decreases in the cold-related death rate in 8 out of 10 cities studied under a high emissions scenario. Adhering to a lower greenhouse gas emissions scenario has the potential to substantially reduce future temperature-related mortality. Copyright © 2017 Elsevier Ltd. All rights reserved.

A synoptic and dynamical characterization of wave-train and blocking cold surge over East Asia

NASA Astrophysics Data System (ADS)

Park, Tae-Won; Ho, Chang-Hoi; Deng, Yi

2014-08-01

Through an agglomerative hierarchical clustering method, cold surges over East Asia are classified into two distinct types based on the spatial pattern of the geopotential height anomalies at 300 hPa. One is the wave-train type that is associated with developing large-scale waves across the Eurasian continent. The other is the blocking type whose occurrence accompanies subarctic blocking. During the wave-train cold surge, growing baroclinic waves induce a southeastward expansion of the Siberian High and strong northerly winds over East Asia. Blocking cold surge, on the other hand, is associated with a southward expansion of the Siberian High and northeasterly winds inherent to a height dipole consisting of the subarctic blocking and the East Asian coastal trough. The blocking cold surge tends to be more intense and last longer compared to the wave-train type. The wave-train cold surge is associated with the formation of a negative upper tropospheric height anomaly southeast of Greenland approximately 12 days before the surge occurrence. Further analysis of isentropic potential vorticity reveals that this height anomaly could originate from the lower stratosphere over the North Atlantic. Cold surge of the blocking type occurs with an amplifying positive geopotential and a negative potential vorticity anomaly over the Arctic and the northern Eurasia in stratosphere. These anomalies resemble the stratospheric signature of a negative phase of the Arctic Oscillation. This stratospheric feature is further demonstrated by the observation that the blocking type cold surge occurs more often when the Arctic Oscillation is in its negative phase.

Soil Crystallinity As a Climate Indicator: Field Experiments on Earth and Mars

NASA Technical Reports Server (NTRS)

Horgan, Briony; Scudder, Noel; Rampe, Elizabeth; Rutledge, Alicia

2016-01-01

Soil crystallinity is largely determined by leaching rates, as high leaching rates favor the rapid precipitation of short order or poorly-crystalline phases like the aluminosilicate allophane. High leaching rates can occur due to high precipitation rates, seasonal monsoons, or weathering of glass, but are also caused by the rapid onset of seasonal melting of snow and ice in cold environments. Thus, cold climate soils are commonly dominated by poorly crystalline phases, which mature into kaolin minerals over time. Thus, we hypothesize that, in some contexts, soils with high abundances of poorly crystalline phases could indicate formation under cold climatic conditions. This model could be helpful in interpreting the poorly-constrained paleoclimate of ancient Mars, as the crystallinity of ancient soils and soil-derived sediments appears to be highly variable in time and space. While strong signatures of crystalline phyllosilicates have been identified in possible ancient paleosols on Mars, Mars Science Laboratory rover investigations of diverse ancient sediments at Gale Crater has shown that they can contain very high abundances (40-50 wt%) of poorly crystalline phases. We hypothesize that these poorly crystalline phases could be the result of weathering by ice/snow melt, perhaps providing support for sustained cold climates on early Mars punctuated by more limited warm climates. Furthermore, such poorly crystalline soils could be highly fertile growth media for future human exploration and colonization on Mars. To test this hypothesis, we are currently using rover-like instrumentation to investigate the mineralogy and chemistry of weathering products generated by snow and ice melt in a Mars analog alpine environment: the glaciated Three Sisters volcanic complex in central Oregon. Alteration in this glacial environment generates high abundances of poorly crystalline phases, many of which have compositions distinct from those identified in previous terrestrial investigations, and perhaps more similar to poorly crystalline phases identified on Mars.

Intrinsically variable stars

NASA Technical Reports Server (NTRS)

Bohm-Vitense, Erika; Querci, Monique

1987-01-01

The characteristics of intrinsically variable stars are examined, reviewing the results of observations obtained with the IUE satellite since its launch in 1978. Selected data on both medium-spectral-class pulsating stars (Delta Cep stars, W Vir stars, and related groups) and late-type variables (M, S, and C giants and supergiants) are presented in spectra, graphs, and tables and described in detail. Topics addressed include the calibration of the the period-luminosity relation, Cepheid distance determination, checking stellar evolution theory by the giant companions of Cepheids, Cepheid masses, the importance of the hydrogen convection zone in Cepheids, temperature and abundance estimates for Population II pulsating stars, mass loss in Population II Cepheids, SWP and LWP images of cold giants and supergiants, temporal variations in the UV lines of cold stars, C-rich cold stars, and cold stars with highly ionized emission lines.

[Influence of cold spot temperature on 253.7 nm resonance spectra line of electrodeless discharge lamps].

PubMed

Dong, Jin-yang; Zhang, Gui-xin; Wang, Chang-quan

2012-01-01

As a kind of new electric light source, electrodeless discharge lamps are of long life, low mercury and non-stroboscopic light. The lighting effect of electrodeless discharge lamps depends on the radiation efficiency of 253.7 nm resonance spectra line to a large extent. The influence of cold temperature on 253.7 nm resonance spectra line has been studied experimentally by atomic emission spectral analysis. It was found that the radiation efficiency of 253.7 nm resonance spectra line is distributed in a nearly normal fashion with the variation of cold spot temperature, in other words, there is an optimum cold spot temperature for an electrodeless discharge lamp. At last, the results of experiments were analyzed through gas discharge theory, which offers guidance to the improvement of lighting effect for electrodeless discharge lamps.

Phase transformation kinetics in rolled U-10 wt. % Mo foil: Effect of post-rolling heat treatment and prior γ-UMo grain size

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

Jana, Saumyadeep; Overman, Nicole; Varga, Tamas

The effect of sub-eutectoid heat treatment on the phase transformation behavior in rolled U-10 wt.percent Mo (U10Mo) foils was systematically investigated. The as-cast 5 mm thick foils were initially homogenized at 900 degrees C for 48 hours and were hot rolled to 2 mm and later cold rolled down to 0.2 mm. Three starting microstructures were evaluated: (i) hot- + cold-rolled to 0.2 mm (as-rolled condition), (ii) hot- + cold-rolled to 0.2 mm + annealed at 700 deg. C for 1 hour, and (iii) hot- + cold-rolled to 0.2 mm + annealed at 1000 deg. C for 60 hours. U10Momore » rolled foils went through various degrees of decomposition when subjected to the sub-eutectoid heat-treatment step and formed a lamellar microstructure through a cellular reaction mostly along the previous γ-UMo grain boundaries.« less

On the application of quantum transport theory to electron sources.

PubMed

Jensen, Kevin L

2003-01-01

Electron sources (e.g., field emitter arrays, wide band-gap (WBG) semiconductor materials and coatings, carbon nanotubes, etc.) seek to exploit ballistic transport within the vacuum after emission from microfabricated structures. Regardless of kind, all sources strive to minimize the barrier to electron emission by engineering material properties (work function/electron affinity) or physical geometry (field enhancement) of the cathode. The unique capabilities of cold cathodes, such as instant ON/OFF performance, high brightness, high current density, large transconductance to capacitance ratio, cold emission, small size and/or low voltage operation characteristics, commend their use in several advanced devices when physical size, weight, power consumption, beam current, and pulse repletion frequency are important, e.g., RF power amplifier such as traveling wave tubes (TWTs) for radar and communications, electrodynamic tethers for satellite deboost/reboost, and electric propulsion systems such as Hall thrusters for small satellites. The theoretical program described herein is directed towards models to evaluate emission current from electron sources (in particular, emission from WBG and Spindt-type field emitter) in order to assess their utility, capabilities and performance characteristics. Modeling efforts particularly include: band bending, non-linear and resonant (Poole-Frenkel) potentials, the extension of one-dimensional theory to multi-dimensional structures, and emission site statistics due to variations in geometry and the presence of adsorbates. Two particular methodologies, namely, the modified Airy approach and metal-semiconductor statistical hyperbolic/ellipsoidal model, are described in detail in their present stage of development.

Infrared (IR) photon-sensitive spectromicroscopy in a cryogenic environment

DOEpatents

Pereverzev, Sergey

2016-06-14

A system designed to suppress thermal radiation background and to allow IR single-photon sensitive spectromicroscopy of small samples by using both absorption, reflection, and emission/luminescence measurements. The system in one embodiment includes: a light source; a plurality of cold mirrors configured to direct light along a beam path; a cold or warm sample holder in the beam path; windows of sample holder (or whole sample holder) are transparent in a spectral region of interest, so they do not emit thermal radiation in the same spectral region of interest; a cold monochromator or other cold spectral device configured to direct a selected fraction of light onto a cold detector; a system of cold apertures and shields positioned along the beam path to prevent unwanted thermal radiation from arriving at the cold monochromator and/or the detector; a plurality of optical, IR and microwave filters positioned along the beam path and configured to adjust a spectral composition of light incident upon the sample under investigation and/or on the detector; a refrigerator configured to maintain the detector at a temperature below 1.0K; and an enclosure configured to: thermally insulate the light source, the plurality of mirrors, the sample holder, the cold monochromator and the refrigerator.

DETECTION OF STRONG MILLIMETER EMISSION FROM THE CIRCUMSTELLAR DUST DISK AROUND V1094 SCO: COLD AND MASSIVE DISK AROUND A T TAURI STAR IN A QUIESCENT ACCRETION PHASE?

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

Tsukagoshi, Takashi; Kohno, Kotaro; Saito, Masao

2011-01-01

We present the discovery of a cold massive dust disk around the T Tauri star V1094 Sco in the Lupus molecular cloud from the 1.1 mm continuum observations with AzTEC on ASTE. A compact (r{approx}< 320 AU) continuum emission coincides with the stellar position having a flux density of 272 mJy, which is the largest among T Tauri stars in Lupus. We also present the detection of molecular gas associated with the star in the five-point observations in {sup 12}CO J = 3-2 and {sup 13}CO J = 3-2. Since our {sup 12}CO and {sup 13}CO observations did not showmore » any signature of a large-scale outflow or a massive envelope, the compact dust emission is likely to come from a disk around the star. The observed spectral energy distribution (SED) of V1094 Sco shows no distinct turnover from near-infrared to millimeter wavelengths, can be well described by a flattened disk for the dust component, and no clear dip feature around 10 {mu}m suggestive of the absence of an inner hole in the disk. We fit a simple power-law disk model to the observed SED. The estimated disk mass ranges from 0.03 M{sub sun} to {approx}>0.12 M{sub sun}, which is one or two orders of magnitude larger than the median disk mass of T Tauri stars in Taurus. The resultant temperature is lower than that of a flared disk with well-mixed dust in hydrostatic equilibrium and is probably attributed to the flattened disk geometry for the dust which the central star cannot illuminate efficiently. From these results, together with the fact that there is no signature of an inner hole in the SED, we suggest that the dust grains in the disk around V1094 Sco sank into the midplane with grain growth by coalescence and are in the evolutional stage just prior to or at the formation of planetesimals.« less

Annual Changes of Paddy Rice Planting Areas in Northeastern Asia from MODIS images in 2000-2014

NASA Astrophysics Data System (ADS)

Xiao, X.; Zhang, G.; Dong, J.; Menarguez, M. A.; Kou, W.; Jin, C.; Qin, Y.; Zhou, Y.; Wang, J.; Moore, B., III

2014-12-01

Knowledge of the area and spatial distribution of paddy rice is important for assessment of food security, management of water resources, estimation of greenhouse gas (methane) emissions, and understanding avian influenza virus transmission. Over the past two decades, paddy rice cultivation has expanded northward in temperate and cold temperate zones, particularly in Northeastern China. There is a need to quantify and map changes in paddy rice planting areas in Northeastern Asia (Japan, North and South Korea, and northeast China) at annual interval. We developed a pixel- and phenology-based image analysis system, MODIS-RICE, to map the paddy rice in Northeastern Asia by using multi-temporal MODIS thermal and surface reflectance imagery. Paddy rice fields during the flooding and transplanting phases have unique physical and spectral characteristics, which make it possible for the development of an automated and robust algorithm to track flooding and transplanting phases of paddy rice fields over time. In this presentation, we will show the MODIS-based annual maps of paddy rice planting area in the Northeastern Asia from 2000-2014 (500-m spatial resolution). Accuracy assessments using high-resolution images show that the resultant paddy rice map of Northeastern Asia had a comparable accuracy to the existing products, including 2010 Landsat-based National Land Cover Dataset (NLCD) of China, the 2010 RapidEye-based paddy rice map in North Korea, and the 2010 AVNIR-2-based National Land Cover Dataset in Japan in terms of both area and spatial pattern of paddy rice. This study has demonstrated that our novel MODIS-Rice system, which use both thermal and optical MODIS data over a year, are simple and robust tools to identify and map paddy rice fields in temperate and cold temperate zones.

Use of quantitative SPECT/CT reconstruction in 99mTc-sestamibi imaging of patients with renal masses.

PubMed

Jones, Krystyna M; Solnes, Lilja B; Rowe, Steven P; Gorin, Michael A; Sheikhbahaei, Sara; Fung, George; Frey, Eric C; Allaf, Mohamad E; Du, Yong; Javadi, Mehrbod S

2018-02-01

Technetium-99m ( 99m Tc)-sestamibi single-photon emission computed tomography/computed tomography (SPECT/CT) has previously been shown to allow for the accurate differentiation of benign renal oncocytomas and hybrid oncocytic/chromophobe tumors (HOCTs) apart from other malignant renal tumor histologies, with oncocytomas/HOCTs showing high uptake and renal cell carcinoma (RCC) showing low uptake based on uptake ratios from non-quantitative single-photon emission computed tomography (SPECT) reconstructions. However, in this study, several tumors fell close to the uptake ratio cutoff, likely due to limitations in conventional SPECT/CT reconstruction methods. We hypothesized that application of quantitative SPECT/CT (QSPECT) reconstruction methods developed by our group would provide more robust separation of hot and cold lesions, serving as an imaging framework on which quantitative biomarkers can be validated for evaluation of renal masses with 99m Tc-sestamibi. Single-photon emission computed tomography data were reconstructed using the clinical Flash 3D reconstruction and QSPECT methods. Two blinded readers then characterized each tumor as hot or cold. Semi-quantitative uptake ratios were calculated by dividing lesion activity by background renal activity for both Flash 3D and QSPECT reconstructions. The difference between median (mean) hot and cold tumor uptake ratios measured 0.655 (0.73) with the QSPECT method and 0.624 (0.67) with the conventional method, resulting in increased separation between hot and cold tumors. Sub-analysis of 7 lesions near the separation point showed a higher absolute difference (0.16) between QPSECT and Flash 3D mean uptake ratios compared to the remaining lesions. Our finding of improved separation between uptake ratios of hot and cold lesions using QSPECT reconstruction lays the foundation for additional quantitative SPECT techniques such as SPECT-UV in the setting of renal 99m Tc-sestamibi and other SPECT/CT exams. With robust quantitative image reconstruction and biomarker analysis, there may be an expanded role for SPECT/CT imaging in renal masses and other pathologic conditions.

40 CFR 86.244-94 - Calculations; exhaust emissions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.244-94 Calculations; exhaust.... Should NOX measurements be calculated, note that the humidity correction factor is not valid at colder...

40 CFR 86.244-94 - Calculations; exhaust emissions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.244-94 Calculations; exhaust.... Should NOX measurements be calculated, note that the humidity correction factor is not valid at colder...

40 CFR 86.244-94 - Calculations; exhaust emissions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.244-94 Calculations; exhaust.... Should NOX measurements be calculated, note that the humidity correction factor is not valid at colder...

40 CFR 63.462 - Batch cold cleaning machine standards.

Code of Federal Regulations, 2012 CFR

2012-07-01

... PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES... splashing against tank walls or parts being cleaned. (7) The owner or operator shall ensure that, when the...

40 CFR 63.462 - Batch cold cleaning machine standards.

Code of Federal Regulations, 2013 CFR

2013-07-01

... PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES... splashing against tank walls or parts being cleaned. (7) The owner or operator shall ensure that, when the...

40 CFR 63.462 - Batch cold cleaning machine standards.

Code of Federal Regulations, 2014 CFR

2014-07-01

... PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES... splashing against tank walls or parts being cleaned. (7) The owner or operator shall ensure that, when the...

40 CFR 63.462 - Batch cold cleaning machine standards.

Code of Federal Regulations, 2010 CFR

2010-07-01

... PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES... splashing against tank walls or parts being cleaned. (7) The owner or operator shall ensure that, when the...

40 CFR 63.462 - Batch cold cleaning machine standards.

Code of Federal Regulations, 2011 CFR

2011-07-01

... PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES... splashing against tank walls or parts being cleaned. (7) The owner or operator shall ensure that, when the...

Apparatus for photocatalytic destruction of internal combustion engine emissions during cold start

DOEpatents

Janata, Jiri; McVay, Gary L.; Peden, Charles H.; Exarhos, Gregory J.

1998-01-01

A method and apparatus for the destruction of emissions from an internal combustion engine wherein a substrate coated with TiO.sub.2 is exposed to a light source in the exhaust system of an internal combustion engine thereby catalyzing oxidation/reduction reactions between gaseous hydrocarbons, carbon monoxide, nitrogen oxides and oxygen in the exhaust of the internal combustion engine.

`Blame' Hawaii for Extreme Cold Air Outbreaks on the US West Coast?

NASA Astrophysics Data System (ADS)

Grotjahn, R.; Zhang, R.

2017-12-01

Short term extreme cold events punctuate the climate record. Though not always captured by monthly or seasonal means, they can have impacts lasting months. Extreme cold air outbreaks affecting the US West Coast are associated with a specific large scale meteorological pattern (LSMP). The LSMP has large meridional displacements of warm and cold air that create a ridge over and south of western Alaska, then a trough downstream moving with the cold air of the CAO, and finally another ridge over the southeastern US. These three features form in that order over several days leading up to the CAO onset. The warm advection creating the Alaskan ridge displaces cold air which is then advected southward along the North American west coast. Our recent work shows that both advections are driven by a lower level highly unusual high pressure center near the Gulf of Alaska. The cold air advection includes a continental interior portion (which sets up an offshore pressure gradient) and a portion off the west coast (air parcels high enough to be little modified before sinking over the US West Coast). In the mid to upper troposphere there are additional cyclonic centers to the south of the Alaskan ridge. Depending on the region compared, the LSMP has notable pattern correlation (up to 0.7) with the Pacific-North American teleconnection (PNA) negative phase pattern. (Others have shown a link between the PNA negative phase and unusual cold over northwestern North America on longer time scales. Here we find a higher frequency LSMP having centers offset from corresponding centers in the negative phase PNA loading pattern.) Even earlier before onset, we find a connection to a stream function structure straddling the equator that shares properties with slow moving equatorial Rossby waves; this pattern includes a trough near Hawaii that appears linked to the Alaskan ridge building that initiates the CAO. Hence, we arrive at our provocative title. All these features in the geopotential and stream function fields are highly significant from bootstrap statistics. The presentation will emphasize the time evolution of these significant features.

A novel approach to the pacemaker infection with non-thermal atmospheric pressure plasma

NASA Astrophysics Data System (ADS)

Zhang, Yuchen; Li, Yu; Li, Yinglong; Yu, Shuang; Li, Haiyan; Zhang, Jue

2017-08-01

Although the pacemaker (PM) is a key cardiac implantable electrical device for life-threatening arrhythmias treatment, the related infection is a challenge. Thus, the aim of this study is to validate cold plasma as a potential technology for the disinfection of infected pacemakers. Fifty donated PMs were cleaned and sterilized before use and then infected with Staphylococcus aureus ( S. aureus). Then, each experimental group was treated with cold plasma treatment for 1 min, 3 min, 5 min and 7 min, while the control group was immersed with sterilized water. Effectiveness of disinfection was evaluated by using CFU counting method and confocal laser scanning microscopy (CLSM). The physicochemical properties of water treated with cold plasma at different time were evaluated, including water temperature change and oxidation reduction potential (ORP). The major reactive species generated by the cold plasma equipment during cold plasma were analyzed with optical emission spectroscopy (OES). No live bacteria were detected with CFU counting method after 7 min of cold plasma treatment, which matches with the CLSM results. The ORP value of water and H2O2 concentration changed significantly after treating with cold plasma. Furthermore, reactive oxygen species (ROS) and reactive nitrogen species (RNS), especially NO, O (777 nm) and O (844 nm) were probably key inactivation agents in cold plasma treatment. These results indicate that cold plasma could be an effective technology for the disinfection of implantable devices.

Multivessel system for cold-vapor mercury generation. Determination of mercury in hair and fish.

PubMed

Boaventura, G R; Barbosa, A C; East, G A

1997-01-01

A multivessel system for the determination of mercury (Hg) by cold-vapor atomic absorption spectrometry (CV-AAS) and inductively coupled plasma atomic emission spectrometry (ICP-AES) was developed. The performance of the proposed device was tested by determining total Hg in quality-control samples of hair and fishes following acid digestion. Application of the apparatus to the determination of Hg by CV-AAS following alkaline digestion was studied as well. The detection limit obtained for CV-AAS was 0.11 ng/mL and for ICP-AES 1.39 ng/mL. The results show that the system is appropriate to be used in techniques involving cold-vapor generation of Hg.

In-Plume Emission Test Stand 2: emission factors for 10- to 100-kW U.S. military generators.

PubMed

Zhu, Dongzi; Nussbaum, Nicholas J; Kuhns, Hampden D; Chang, M-C Oliver; Sodeman, David; Uppapalli, Sebastian; Moosmüller, Hans; Chow, Judith C; Watson, John G

2009-12-01

Although emissions of air pollutants from some military tactical equipment are not subject to the emissions standards, local communities near military bases must conform to the National Ambient Air Quality Standards. Military diesel generators are widely used in training. A portable in-plume system was used to measure fuel-based emission factors (EFs) for particulate matter (PM), carbon monoxide (CO), nitrogen oxides (NOx), and hydrocarbons (HCs) for 30-, 60-, and 100-kW generators at five load levels and for cold starts. It was found that EFs depend on multiple parameters including engine size, engine load, unit age, and total running hours. The average CO EF of generators tested was 5% lower, and the average NOx EF was 63% lower than AP-42 estimates; average PM EF was 80% less than the AP-42 estimates. A 2002 model-year 60-kW engine produced 25% less PM than a 1995 engine of the same family with similar running hours. CO EFs decrease with increasing engine load, NOx EFs increase up to mid-loads and decrease slightly at high loads, PM EFs increase with loads for 30- and 60-kW engines. CO and PM have higher EFs and NOx has a lower EF during cold starts than during hot-stabilized operation. PM chemical source profiles were also examined.

Dust emission mechanisms in the central Sahara: new insights from remote field observations

NASA Astrophysics Data System (ADS)

Allen, C.; Washington, R.; Engelstaedter, S.

2013-12-01

North Africa is the world's largest source of mineral aerosol (dust). The Fennec Project, an international consortium led by the University of Oxford, is the first project to systematically instrument the remote central Sahara Desert. These observations have, among others, provided new insights into the atmospheric mechanisms of dust emission. Bordj Badji Mokhtar, in south-west Algeria, is within kilometres of the centre of the global mean summer dust maximum. The site, operated by Fennec partners ONM Algerie, has been heavily instrumented since summer 2011. During the Intensive Observation Period (IOP) in June 2011, four main emission mechanisms were observed and documented: cold pool outflows, low level jets (LLJs), monsoon surges and dry convective plumes. Establishing the relative importance of dust emission mechanisms has been a long-standing research goal. A detailed partitioning exercise of dust events during the IOP shows that 45% of the dust over BBM was generated by local emission in cold pool outflows, 14% by LLJs and only 2% by dry convective plumes. 27% of the dust was advected to the site rather than locally emitted and 12% of the dust was residual or ';background' dust. The work shows the primacy of cold pool outflows for dust emission in the region and also the important contribution of dust advection. In accordance with long-held ideas, the cube of wind speed is strongly correlated with dust emission. Surprisingly however, particles in long-range advection (>500km) were found to be larger than locally emitted dust. Although a clear LLJ wind structure is evident in the mean diurnal cycle during the IOP (12m/s peak winds at 935hPa between 04-05h), LLJs are only responsible for a relatively small amount of dust emission. There is significant daily variability in LLJ strength; the strongest winds are produced by a relatively small number of events. The position and strength of the Saharan Heat Low is strongly associated with the development (or otherwise) of LLJs. However, the presence of a LLJ is not a guarantee of dust emission. Momentum calculations show that dust emission always occurs if momentum mixes down to the surface, but mix-down does not always happen - particularly if the surface temperature inversion is strong or ground heating is weak. Fennec findings are not only providing new insights into dust emission processes, they are also an excellent test-bed for models and satellite algorithms in a region where high-quality ';ground-truthing' measurements have been scarce. Conditions of (relatively) high water vapour appear to be a common cause of error. In one model, wind speeds in the core of monsoon LLJs are underestimated by 8.5m/s compared to observations.

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

Abboud, Alexander; Guillen, Donna Post; Pokorny, Richard

At the Hanford site in the state of Washington, more than 56 million gallons of radioactive waste is stored in underground tanks. The cleanup plan for this waste is vitrification at the Waste Treatment Plant (WTP), currently under construction. At the WTP, the waste will be blended with glass-forming materials and heated to 1423K, then poured into stainless steel canisters to cool and solidify. A fundamental understanding of the glass batch melting process is needed to optimize the process to reduce cost and decrease the life cycle of the cleanup effort. The cold cap layer that floats on the surfacemore » of the glass melt is the primary reaction zone for the feed-to-glass conversion. The conversion reactions include water release, melting of salts, evolution of batch gases, dissolution of quartz and the formation of molten glass. Obtaining efficient heat transfer to this region is crucial to achieving high rates of glass conversion. Computational fluid dynamics (CFD) modeling is being used to understand the heat transfer dynamics of the system and provide insight to optimize the process. A CFD model was developed to simulate the DM1200, a pilot-scale melter that has been extensively tested by the Vitreous State Laboratory (VSL). Electrodes are built into the melter to provide Joule heating to the molten glass. To promote heat transfer from the molten glass into the reactive cold cap layer, bubbling of the molten glass is used to stimulate forced convection within the melt pool. A three-phase volume of fluid approach is utilized to model the system, wherein the molten glass and cold cap regions are modeled as separate liquid phases, and the bubbling gas and plenum regions are modeled as one lumped gas phase. The modeling of the entire system with a volume of fluid model allows for the prescription of physical properties on a per-phase basis. The molten glass phase and the gas phase physical properties are obtained from previous experimental work. Finding representative properties for the cold cap region is more difficult, as this region is not a true liquid, but rather a multilayer region consisting of a porous and a foamy layer. Physical properties affecting heat transfer, namely the thermal conductivity and heat capacity, have been fit to closely match data and observations from laboratory experiments. Data from xray tomography and quenching of laboratory-scale cold caps provide insight into the topology of bubble distribution within the cold cap at various temperatures. Heat transfer within the melter was validated by comparison with VSL data for the pilot-scale melter.« less

Advanced Collaborative Emissions Study (ACES)

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

Greenbaum, Daniel; Costantini, Maria; Van Erp, Annemoon

2013-12-31

The objective of the Advanced Collaborative Emissions Study (ACES) was to determine before widespread commercial deployment whether or not the new, energy-efficient, heavy duty diesel engines (2007 and 2010 EPA Emissions Standards Compliant) may generate anticipated toxic emissions that could adversely affect the environment and human health. ACES was planned to take place in three phases. In Phase 1, extensive emissions characterization of four production-intent prototype engine and control systems designed to meet 2007 standards for nitrogen oxides (NOx) and particulate matter (PM) was conducted at an existing emissions characterization facility: Southwest Research Institute (SwRI). One of the tested enginesmore » was selected (at random, after careful comparison of results) for health testing in Phase 3. In Phase 2, extensive emission characterization of three production-intent prototype engine and control systems meeting the 2010 standards (including more advanced NOx controls to meet the more stringent 2010 NOx standards) was conducted at the same test facility. In Phase 3, one engine/aftertreatment system selected from Phase 1 was further characterized during health effects studies (at an existing inhalation toxicology laboratory: Lovelace Respiratory Research Institute, [LRRI]) to form the basis of the ACES safety assessment. The Department of Energy (DOE) award provided funding for emissions characterization in Phases 1 and 2 as well as exposure characterization in Phase 3. The main health analyses in Phase 3 were funded separately and are not reported here.« less

[Research advances in mathematical model of coniferous trees cold hardiness].

PubMed

Zhang, Gang; Wang, Ai-Fang

2007-07-01

Plant cold hardiness has complicated attributes. This paper introduced the research advances in establishing the dynamic models of coniferous trees cold hardiness, with the advantages and disadvantages of the models presented and the further studies suggested. In the models established initially, temperature was concerned as the only environmental factor affecting the cold hardiness, and the concept of stationary level of cold hardiness was introduced. Due to the obvious prediction errors of these models, the stationary level of cold hardiness was modeled later by assuming the existence of an additive effect of temperature and photoperiod on the increase of cold hardiness. Furthermore, the responses of the annual development phases for cold hardiness to environment were considered. The model researchers have paid more attention to the additive effect models, and run some experiments to test the additivity principle. However, the research results on Scots pine (Pinus sylvestris) indicated that its organs did not support the presumption of an additive response of cold hardiness by temperature and photoperiod, and the interaction between environmental factors should be taken into account. The mathematical models of cold hardiness need to be developed and improved.

Laser interferometry and emission spectroscopy measurements of cold-sprayed copper thermite shocked to 35 GPa

NASA Astrophysics Data System (ADS)

Neel, Christopher; Lacina, David; Johnson, Stephanie

2017-01-01

Plate impact experiments were conducted on a cold-sprayed Al-CuO thermite at peak stresses between 5-35 GPa to determine the Hugoniot curve and characterize any shock induced energetic reaction. Photon Doppler Velocimetry (PDV) measurements were used to obtain particle velocity histories and shock speed information for both the shock loading and unloading behavior of the material. A jump in shock velocity was observed in the Hugoniot curve when the material was shocked beyond 20 GPa, suggesting a volume-increasing reaction occurs in this shocked Al-CuO thermite near 20 GPa. To better characterize any shock-induced thermite reactions, emission spectroscopy measurements were obtained at stresses above 20 GPa. The best time-resolved spectra obtained thus far, at 25 GPa, does not support the fast thermite reaction hypothesis.

New ALMA constraints on the star-forming interstellar medium at low metallicity: a 50 pc view of the blue compact dwarf galaxy SBS 0335-052

NASA Astrophysics Data System (ADS)

Cormier, D.; Bendo, G. J.; Hony, S.; Lebouteiller, V.; Madden, S. C.; Galliano, F.; Glover, S. C. O.; Klessen, R. S.; Abel, N. P.; Bigiel, F.; Clark, P. C.

2017-06-01

Properties of the cold interstellar medium of low-metallicity galaxies are not well known due to the faintness and extremely small scale on which emission is expected. We present deep ALMA band 6 (230 GHz) observations of the nearby, low-metallicity (12 + log (O/H) = 7.25) blue compact dwarf galaxy SBS 0335-052 at an unprecedented resolution of 0.2 arcsec (52 pc). The 12CO J = 2→1 line is not detected and we report a 3σ upper limit of LCO(2-1) = 3.6 × 104 K km s-1 pc2. Assuming that molecular gas is converted into stars with a given depletion time, ranging from 0.02 to 2 Gyr, we find lower limits on the CO-to-H2 conversion factor αCO in the range 102-104 M⊙ pc-2 (K km s-1)-1. The continuum emission is detected and resolved over the two main super star clusters. Re-analysis of the IR-radio spectral energy distribution suggests that the mm-fluxes are not only free-free emission but are most likely also associated with a cold dust component coincident with the position of the brightest cluster. With standard dust properties, we estimate its mass to be as large as 105 M⊙. Both line and continuum results suggest the presence of a large cold gas reservoir unseen in CO even with ALMA.

Seasonal variations and source apportionment of atmospheric PM2.5-bound polycyclic aromatic hydrocarbons in a mixed multi-function area of Hangzhou, China.

PubMed

Lu, Hao; Wang, Shengsheng; Li, Yun; Gong, Hui; Han, Jingyi; Wu, Zuliang; Yao, Shuiliang; Zhang, Xuming; Tang, Xiujuan; Jiang, Boqiong

2017-07-01

To reveal the seasonal variations and sources of PM 2.5 -bound polycyclic aromatic hydrocarbons (PAHs) during haze and non-haze episodes, daily PM 2.5 samples were collected from March 2015 to February 2016 in a mixed multi-function area in Hangzhou, China. Ambient concentrations of 16 priority-controlled PAHs were determined. The sums of PM 2.5 -bound PAH concentrations during the haze episodes were 4.52 ± 3.32 and 13.6 ± 6.29 ng m -3 in warm and cold seasons, respectively, which were 1.99 and 1.49 times those during the non-haze episodes. Four PAH sources were identified using the positive matrix factorization model and conditional probability function, which were vehicular emissions (45%), heavy oil combustion (23%), coal and natural gas combustion (22%), and biomass combustion (10%). The four source concentrations of PAHs consistently showed higher levels in the cold season, compared with those in the warm season. Vehicular emissions were the most considerable sources that result in the increase of PM 2.5 -bound PAH levels during the haze episodes, and heavy oil combustion played an important role in the aggravation of haze pollution. The analysis of air mass back trajectories indicated that air mass transport had an influence on the PM 2.5 -bound PAH pollution, especially on the increased contributions from coal combustion and vehicular emissions in the cold season.

Reduced Cortisol and Metabolic Responses of Thin Ewes to an Acute Cold Challenge in Mid-Pregnancy: Implications for Animal Physiology and Welfare

PubMed Central

Verbeek, Else; Oliver, Mark Hope; Waas, Joseph Rupert; McLeay, Lance Maxwell; Blache, Dominique; Matthews, Lindsay Ross

2012-01-01

Background Low food availability leading to reductions in Body Condition Score (BCS; 0 indicates emaciation and 5 obesity) in sheep often coincides with low temperatures associated with the onset of winter in New Zealand. The ability to adapt to reductions in environmental temperature may be impaired in animals with low BCS, in particular during pregnancy when metabolic demand is higher. Here we assess whether BCS affects a pregnant animal's ability to cope with cold challenges. Methods Eighteen pregnant ewes with a BCS of 2.7±0.1 were fed to attain low (LBC: BCS2.3±0.1), medium (MBC: BCS3.2±0.2) or high BCS (HBC: BCS3.6±0.2). Shorn ewes were exposed to a 6-h acute cold challenge in a climate-controlled room (wet and windy conditions, 4.4±0.1°C) in mid-pregnancy. Blood samples were collected during the BCS change phase, acute cold challenge and recovery phase. Results During the BCS change phase, plasma glucose and leptin concentrations declined while free fatty acids (FFA) increased in LBC compared to MBC (P<0.01, P<0.01 and P<0.05, respectively) and HBC ewes (P<0.05, P<0.01 and P<0.01, respectively). During the cold challenge, plasma cortisol concentrations were lower in LBC than MBC (P<0.05) and HBC ewes (P<0.05), and FFA and insulin concentrations were lower in LBC than HBC ewes (P<0.05 and P<0.001, respectively). Leptin concentrations declined in MBC and HBC ewes while remaining unchanged in LBC ewes (P<0.01). Glucose concentrations and internal body temperature (Tcore) increased in all treatments, although peak Tcore tended to be higher in HBC ewes (P<0.1). During the recovery phase, T4 concentrations were lower in LBC ewes (P<0.05). Conclusion Even though all ewes were able to increase Tcore and mobilize glucose, low BCS animals had considerably reduced cortisol and metabolic responses to a cold challenge in mid-pregnancy, suggesting that their ability to adapt to cold challenges through some of the expected pathways was reduced. PMID:22662144

Flexible attosecond beamline for high harmonic spectroscopy and XUV/near-IR pump probe experiments requiring long acquisition times

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

Weber, S. J., E-mail: sebastien.weber@cea.fr; Manschwetus, B.; Billon, M.

2015-03-15

We describe the versatile features of the attosecond beamline recently installed at CEA-Saclay on the PLFA kHz laser. It combines a fine and very complete set of diagnostics enabling high harmonic spectroscopy (HHS) through the advanced characterization of the amplitude, phase, and polarization of the harmonic emission. It also allows a variety of photo-ionization experiments using magnetic bottle and COLTRIMS (COLd Target Recoil Ion Momentum Microscopy) electron spectrometers that may be used simultaneously, thanks to a two-foci configuration. Using both passive and active stabilization, special care was paid to the long term stability of the system to allow, using bothmore » experimental approaches, time resolved studies with attosecond precision, typically over several hours of acquisition times. As an illustration, applications to multi-orbital HHS and electron-ion coincidence time resolved spectroscopy are presented.« less

Cold CO Gas in the Envelopes of FU Orionis-type Young Eruptive Stars

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

Kóspál, Á.; Ábrahám, P.; Moór, A.

FU Orionis-type objects (FUors) are young stellar objects experiencing large optical outbursts due to highly enhanced accretion from the circumstellar disk onto the star. FUors are often surrounded by massive envelopes, which play a significant role in the outburst mechanism. Conversely, the subsequent eruptions might gradually clear up the obscuring envelope material and drive the protostar on its way to become a disk-only T Tauri star. Here we present an APEX {sup 12}CO and {sup 13}CO survey of eight southern and equatorial FUors. We measure the mass of the gaseous material surrounding our targets, locate the source of the COmore » emission, and derive physical parameters for the envelopes and outflows, where detected. Our results support the evolutionary scenario where FUors represent a transition phase from envelope-surrounded protostars to classical T Tauri stars.« less

Gas and grain chemical composition in cold cores as predicted by the Nautilus three-phase model

NASA Astrophysics Data System (ADS)

Ruaud, Maxime; Wakelam, Valentine; Hersant, Franck

2016-07-01

We present an extended version of the two-phase gas-grain code NAUTILUS to the three-phase modelling of gas and grain chemistry of cold cores. In this model, both the mantle and the surface are considered as chemically active. We also take into account the competition among reaction, diffusion and evaporation. The model predictions are confronted to ice observations in the envelope of low-mass and massive young stellar objects as well as towards background stars. Modelled gas-phase abundances are compared to species observed towards TMC-1 (CP) and L134N dark clouds. We find that our model successfully reproduces the observed ice species. It is found that the reaction-diffusion competition strongly enhances reactions with barriers and more specifically reactions with H2, which is abundant on grains. This finding highlights the importance having a good approach to determine the abundance of H2 on grains. Consequently, it is found that the major N-bearing species on grains go from NH3 to N2 and HCN when the reaction-diffusion competition is taken into account. In the gas phase and before a few 105 yr, we find that the three-phase model does not have a strong impact on the observed species compared to the two-phase model. After this time, the computed abundances dramatically decrease due to the strong accretion on dust, which is not counterbalanced by the desorption less efficient than in the two-phase model. This strongly constrains the chemical age of cold cores to be of the order of few 105 yr.

The Greenhouse Gas Emission from Portland Cement Concrete Pavement Construction in China.

PubMed

Ma, Feng; Sha, Aimin; Yang, Panpan; Huang, Yue

2016-06-24

This study proposes an inventory analysis method to evaluate the greenhouse gas (GHG) emissions from Portland cement concrete pavement construction, based on a case project in the west of China. The concrete pavement construction process was divided into three phases, namely raw material production, concrete manufacture and pavement onsite construction. The GHG emissions of the three phases are analyzed by a life cycle inventory method. The CO₂e is used to indicate the GHG emissions. The results show that for 1 km Portland cement concrete pavement construction, the total CO₂e is 8215.31 tons. Based on the evaluation results, the CO₂e of the raw material production phase is 7617.27 tons, accounting for 92.7% of the total GHG emissions; the CO₂e of the concrete manufacture phase is 598,033.10 kg, accounting for 7.2% of the total GHG emissions. Lastly, the CO₂e of the pavement onsite construction phase is 8396.59 kg, accounting for only 0.1% of the total GHG emissions. The main greenhouse gas is CO₂ in each phase, which accounts for more than 98% of total emissions. N₂O and CH₄ emissions are relatively insignificant.

Efimov-driven phase transitions of the unitary Bose gas.

PubMed

Piatecki, Swann; Krauth, Werner

2014-03-20

Initially predicted in nuclear physics, Efimov trimers are bound configurations of three quantum particles that fall apart when any one of them is removed. They open a window into a rich quantum world that has become the focus of intense experimental and theoretical research, as the region of 'unitary' interactions, where Efimov trimers form, is now accessible in cold-atom experiments. Here we use a path-integral Monte Carlo algorithm backed up by theoretical arguments to show that unitary bosons undergo a first-order phase transition from a normal gas to a superfluid Efimov liquid, bound by the same effects as Efimov trimers. A triple point separates these two phases and another superfluid phase, the conventional Bose-Einstein condensate, whose coexistence line with the Efimov liquid ends in a critical point. We discuss the prospects of observing the proposed phase transitions in cold-atom systems.

Energy and mass balance in the three-phase interstellar medium

NASA Technical Reports Server (NTRS)

Wang, Zhong; Cowie, Lennox L.

1988-01-01

Details of the energy and mass balances are considered in the context of a three-phase interstellar medium. The rates of mass exchange between the different phases are derived based on the pressure variations created by supernova remnant expansions. It is shown that the pressure-confined warm and cold gases have stable temperatures under a variety of interstellar conditions. The three-phase quasi-static configuration is found to be a natural outcome, and both warm and cold phases generally contribute about half of the total mass density to the diffuse interstellar gas. The model is also likely to be self-regulatory in the sense that variations of the input parameters do not strongly alter the general result, which is consistent with most current observations. The consequences of extreme conditions on this model are considered, and the possible implications for interstellar medium in other galaxies are briefly discussed.

Exploring the relevance of gas-phase structures to biology: cold ion spectroscopy of the decapeptide neurokinin A.

PubMed

Pereverzev, A Y; Boyarkin, O V

2017-02-01

Linking the intrinsic tertiary structures of biomolecules to their native geometries is a central prerequisite for making gas-phase studies directly relevant to biology. The isolation of molecules in the gas phase eliminates hydrophilic interactions with solvents, to some extent mimicking a hydrophobic environment. Intrinsic structures therefore may resemble native ones for peptides that in vivo reside in a hydrophobic environment (e.g., binding pockets of receptors). In this study, we investigate doubly protonated neurokinin A (NKA) using IR-UV double resonance cold ion spectroscopy and find only five conformers of this decapeptide in the gas phase. In contrast, NMR data show that in aqueous solutions, NKA exhibits high conformational heterogeneity, which reduces to a few well-defined structures in hydrophobic micelles. Do the gas-phase structures of NKA resemble these native structures? The IR spectra reported here allow the validation of future structural calculations that may answer this question.

Observations of electron gyroharmonic waves and the structure of the Io torus. [jupiter 1 spacecraft radio astronomy experiment

NASA Technical Reports Server (NTRS)

Birmingham, T. J.; Alexander, J. K.; Desch, M. D.; Hubbard, R. F.; Pedersen, B. M.

1980-01-01

Narrow-banded emissions were observed by the Planetary Radio Astronomy experiment on the Voyager 1 spacecraft as it traversed the Io plasma torus. These waves occur between harmonics of the electron gyrofrequency and are the Jovian analogue of electrostatic emissions observed and theoretically studied for the terrestrial magnetosphere. The observed frequencies always include the component near the upper hybrid resonant frequency, (fuhr) but the distribution of the other observed emissions varies in a systematic way with position in the torus. A refined model of the electron density variation, based on identification of the fuhr line, is included. Spectra of the observed waves are analyzed in terms of the linear instability of an electron distribution function consisting of isotropic cold electrons and hot losscone electrons. The positioning of the observed auxiliary harmonics with respect to fuhr is shown to be an indicator of the cold to hot temperature ratio. It is concluded that this ratio increases systematically by an overall factor of perhaps 4 or 5 between the inner and outer portions of the torus.

Laboratory simulation of photoionized plasma among astronomical compact objects

NASA Astrophysics Data System (ADS)

Fujioka, Shinsuke; Yamamoto, Norimasa; Wang, Feilu; Salzmann, David; Li, Yutong; Rhee, Yong-Joo; Nishimura, Hiroaki; Takabe, Hideaki; Mima, Kunioki

2008-11-01

X-ray line emission with several-keV of photon energy was observed from photoionized accreting clouds, for example CYGNUS X-3 and VELA X-1, those are exposed by hard x-ray continuum from the compact objects, such as neutron stars, black holes, or white dwarfs, although accreting clouds are thermally cold. The x-ray continuum-induced line emission gives a good insight to the accreting clouds. We will present a novel laboratory simulation of the photoionized plasma under well-characterized conditions by using high-power laser facility. Blackbody radiator with 500-eV of temperature, as a miniature of a hot compact object, was created.Silicon (Si) plasma with 30-eV of electron temperature was produced in the vicinity of the 0.5-keV blackbody radiator. Line emissions of lithium- and helium-like Si ions was clearly observed around 2-keV of photon-energy from the thermally cold Si plasma, this result is hardly interpreted without consideration of the photoionization. Atomic kinetics code reveals importance of inner-shell ionization directly caused by incoming hard x-rays.

Cold and warm swelling of hydrophobic polymers

NASA Astrophysics Data System (ADS)

de Los Rios, Paolo; Caldarelli, Guido

2001-03-01

We introduce a polymer model where the transition from swollen to compact configurations is due to interactions between the monomers and the solvent. These interactions are the origin of the effective attractive interactions between hydrophobic amino acids in proteins. We find that in the low and high temperature phases polymers are swollen, and there is an intermediate phase where the most favorable configurations are compact. We argue that such a model captures in a single framework both the cold and the warm denaturation experimentally detected for thermosensitive polymers and for proteins.

Optimization evaluation of cutting technology based on mechanical parts

NASA Astrophysics Data System (ADS)

Wang, Yu

2018-04-01

The relationship between the mechanical manufacturing process and the carbon emission is studied on the basis of the process of the mechanical manufacturing process. The formula of carbon emission calculation suitable for mechanical manufacturing process is derived. Based on this, a green evaluation method for cold machining process of mechanical parts is proposed. The application verification and data analysis of the proposed evaluation method are carried out by an example. The results show that there is a great relationship between the mechanical manufacturing process data and carbon emissions.

Acoustic emission investigation of cold cracking in gas metal-arc welding of AISI 4340 steel

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

Fang, C.K.; Kannatey-Asibu, E. Jr.; Barber, J.R.

1995-06-01

Acoustic emission (AE) has been used to investigate the propagation of a finite crack in a weldment subjected to nonuniform longitudinal residual stresses during gas metal arc welding (GMAW). Cold cracking in selected weldments was accelerated using the electrochemical method to cathodically charge the weldments with hydrogen in order to induce hydrogen embrittlement. Cold cracking was observed about 40 min after charging in the specimen subjected to hydrogen embrittlement, while it was observed two days after welding for the one that was left in the atmosphere. The AE signals were generated as the specimen cracked and were recorded, and themore » effects from structure and instrumentation were removed from the measured signals by deconvolution in the frequency domain. Most of the high-amplitude signal components were found to be clustered in the frequency range below 200 kHz. The experimentally obtained spectrum was compared with theoretical results derived in earlier work, and reasonable agreement with theoretical surface displacement in both time and frequency domains was obtained. The envelopes for both spectra were found to decrease with increasing frequency, while the fluctuations in each curve diminished at high frequencies.« less

Capsinoids activate brown adipose tissue (BAT) with increased energy expenditure associated with subthreshold 18-fluorine fluorodeoxyglucose uptake in BAT-positive humans confirmed by positron emission tomography scan.

PubMed

Sun, Lijuan; Camps, Stefan G; Goh, Hui Jen; Govindharajulu, Priya; Schaefferkoetter, Joshua D; Townsend, David W; Verma, Sanjay K; Velan, S Sendhil; Sun, Lei; Sze, Siu Kwan; Lim, Su Chi; Boehm, Bernhard Otto; Henry, Christiani Jeyakumar; Leow, Melvin Khee-Shing

2018-01-01

Capsinoids are reported to increase energy expenditure (EE) via brown adipose tissue (BAT) stimulation. However, imaging of BAT activation by capsinoids remains limited. Because BAT activation is a potential therapeutic strategy for obesity and related metabolic disorders, we sought to prove that capsinoid-induced BAT activation can be visualized by 18-fluorine fluorodeoxyglucose (18F-FDG) positron emission tomography (PET). We compared capsinoids and cold exposure on BAT activation and whole-body EE. Twenty healthy participants (8 men, 12 women) with a mean age of 26 y (range: 21-35 y) and a body mass index (kg/m2) of 21.7 (range: 18.5-26.0) underwent 18F-FDG PET and whole-body calorimetry after ingestion of 12 mg capsinoids or ≤2 h of cold exposure (∼14.5°C) in a crossover design. Mean standardized uptake values (SUVs) of the region of interest and BAT volumes were calculated. Blood metabolites were measured before and 2 h after each treatment. All of the participants showed negligible 18F-FDG uptake post-capsinoid ingestion. Upon cold exposure, 12 participants showed avid 18F-FDG uptake into supraclavicular and lateral neck adipose tissues (BAT-positive group), whereas the remaining 8 participants (BAT-negative group) showed undetectable uptake. Capsinoids and cold exposure increased EE, although cold induced a 2-fold increase in whole-body EE and higher fat oxidation, insulin sensitivity, and HDL cholesterol compared with capsinoids. Capsinoids only increased EE in BAT-positive participants, which suggests that BAT mediates EE evoked by capsinoids. This implies that capsinoids stimulate BAT to a lesser degree than cold exposure as evidenced by 18F-FDG uptake below the presently accepted SUV thresholds defining BAT activation. This trial was registered at www.clinicaltrials.gov as NCT02964442. © 2018 American Society for Nutrition. All rights reserved.

Analysis of the Emission Inventories and Model-Ready Emission Datasets of Europe and North America for Phase 2 of the AQMEII Project

EPA Science Inventory

This paper highlights the development of the emission inventories and emission processing for Europe (EU) and North America (NA) in the second phase of the Air Quality Model Evaluation International Initiative (AQMEII) project. The main purpose of the second phase of the AQMEII...

Lurking systematics in dust-based estimates of galaxy ISM masses

NASA Astrophysics Data System (ADS)

Janowiecki, Steven; Cortese, Luca; Catinella, Barbara; Goodwin, Adelle

2018-01-01

We use galaxies from the Herschel Reference Survey to evaluate commonly used indirect predictors of cold gas masses. With observations of cold neutral atomic and molecular gas, we calibrate predictive relationships using infrared dust emission and gas depletion time methods. We derive a set of self-consistent predictions of cold gas masses with ~20% scatter, and the greatest accuracy for total cold gas mass. However, significant systematic residuals are found in all calibrations which depend strongly on the molecular-to-atomic hydrogen mass ratio, and they can over/under-predict gas masses by >0.5 dex. Extending these types of indirect predictions to high-z galaxies (e.g., using ALMA observations of dust continuum to determine gas masses) requires implicit assumptions about the conditions in their interstellar medium. Any scaling relations derived using predicted gas masses may be more closely related to the calibrations used than to the actual galaxies observed.

Optimization of Domestic-Size Renewable Energy System Designs Suitable for Cold Climate Regions

NASA Astrophysics Data System (ADS)

Akpan, Itoro Etim; Sasaki, Masafumi; Endoh, Noboru

Five different kinds of domestic-size renewable energy system configurations for very cold climate regions were investigated. From detailed numerical modeling and system simulations, it was found that the consumption of fuel oil for the auxiliary boiler in residential-type households can almost be eliminated with a renewable energy system that incorporates photovoltaic panel arrays for electricity generation and two storage tanks: a well-insulated electric water storage tank that services the hot water loads, and a compact boiler/geothermal heat pump tank for room heating during very cold seasons. A reduction of Greenhouse Gas Emissions (GHG) of about 28% was achieved for this system compared to an equivalent conventional system. The near elimination of the use of fuel oil in this system makes it very promising for very cold climate regions in terms of energy savings because the running cost is not so dependent on the unstable nature of global oil prices.

40 CFR 600.113-12 - Fuel economy and carbon-related exhaust emission calculations for FTP, HFET, US06, SC03 and cold...

Code of Federal Regulations, 2011 CFR

2011-07-01

... weighted grams/mile values for total hydrocarbons (HC), carbon monoxide (CO), and carbon dioxide (CO2); and... input of grams/mile values for nitrous oxide (N2O) and methane (CH4). Emissions shall be determined for...) Calculate the FTP fuel economy. (1) Calculate the weighted grams/mile values for the FTP test for CO2, HC...

Apparatus for photocatalytic destruction of internal combustion engine emissions during cold start

DOEpatents

Janata, J.; McVay, G.L.; Peden, C.H.; Exarhos, G.J.

1998-07-14

A method and apparatus are disclosed for the destruction of emissions from an internal combustion engine wherein a substrate coated with TiO{sub 2} is exposed to a light source in the exhaust system of an internal combustion engine thereby catalyzing oxidation/reduction reactions between gaseous hydrocarbons, carbon monoxide, nitrogen oxides and oxygen in the exhaust of the internal combustion engine. 4 figs.

The use of lipids as phase change materials for thermal energy storage

USDA-ARS?s Scientific Manuscript database

Phase change materials (PCMs) are substances capable of absorbing and releasing large 2 amounts of thermal energy (heat or cold) as latent heat over constant temperature as they 3 undergo a change in state of matter (phase transition), commonly, between solid and 4 liquid phases. Since the late 194...

Assessment of emissions and removal of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) at start-up periods in a hazardous waste incinerator.

PubMed

Karademir, Aykan; Korucu, M Kemal

2013-07-01

A study was conducted to observe the changes in polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/F) levels and congener profiles in the flue gas of a hazardous waste incinerator during two start-up periods. Flue gas samplings were performed simultaneously through Air Pollution Control Devices (APCDs) (including boiler outlet, electrostatic precipitator (ESP) outlet, wet scrubbers (WS) outlet, and activated carbon (AC) filter outlet) in different combustion temperatures during a planned cold (long) start-up and an unplanned warm (short) start-up. The results showed that PCDD/F concentrations could be elevated during the start-up periods up to levels 3-4 times higher than those observed in the normal operation. Especially lower combustion temperatures in the short start-ups may cause high PCDD/F concentrations in the raw flue gas. Assessment of combustion temperatures and Furans/Dioxins values indicated that surface-catalyzed de novo synthesis was the dominant pathway in the formation of PCDD/Fs in the combustion units. PCDD/F removal efficiencies of Air Pollution Control Devices suggested that formation by de novo synthesis existed in ESP also when in operation, leading to increase of gaseous phase PCDD/Fs in ESP Particle-bound PCDD/Fs were removed mainly by ESP and WS, while gaseous phase PCDD/Fs were removed by WS, and more efficiently by AC filter. This paper evaluates PCDD/F emissions and removal performances of APCDs (ESP, wet scrubbers, and activated carbon) during two start-up periods in an incinerator. The main implications are the following: (1) start-up periods increase PCDD/F emissions up to 2-3 times in the incinerator; (2) low combustion temperatures in start-ups cause high PCDD/F emissions in raw gas; (3) formation of PCDD/Fs by de novo synthesis occurs in ESP; (4) AC is efficient in removing gaseous PCDD/Fs, but may increase particle-bound ones; and (5) scrubbers remove both gaseous and particle-bound PCDD/Fs efficiently.

Lung inflation with hydrogen during the cold ischemia phase decreases lung graft injury in rats

PubMed Central

Liu, Rongfang; Fang, Xianhai; Meng, Chao; Xing, Jingchun; Liu, Jinfeng; Yang, Wanchao

2015-01-01

Hydrogen has antioxidant and anti-inflammatory effects on lung ischemia–reperfusion injury when it is inhaled by donor or/and recipient. This study examined the effects of lung inflation with 3% hydrogen during the cold ischemia phase on lung graft function in rats. The donor lung was inflated with 3% hydrogen, 40% oxygen, and 57% nitrogen at 5 mL/kg, and the gas was replaced every 20 min during the cold ischemia phase for 2 h. In the control group, the donor lung was inflated with 40% oxygen and 60% nitrogen at 5 mL/kg. The recipient was euthanized 2 h after orthotropic lung transplantation. The hydrogen concentration in the donor lung during the cold ischemia phase was 1.99–3%. The oxygenation indices in the arterial blood and pulmonary vein blood were improved in the hydrogen group. The inflammation response indices, including lung W/D ratio, the myeloperoxidase activity in the grafts, and the levels of IL-8 and TNF-α in serum, were significantly lower in the hydrogen group (5.2 ± 0.8, 0.76 ± 0.32 U/g, 340 ± 84 pg/mL, and 405 ± 115 pg/mL, respectively) than those in the control group (6.5 ± 0.7, 1.1 ± 0.5 U/g, 443 ± 94 pg/mL, and 657 ± 96 pg/mL, respectively (P < 0.05), and the oxidative stress indices, including the superoxide dismutase activity and the level of malonaldehyde in lung grafts were improved after hydrogen application. Furthermore, the lung injury score determined by histopathology, the cell apoptotic index, and the caspase-3 protein expression in lung grafts were decreased after hydrogen treatment, and the static pressure–volume curve of lung graft was improved by hydrogen inflation. In conclusion, lung inflation with 3% hydrogen during the cold ischemia phase alleviated lung graft injury and improved graft function. PMID:25662956

On the Disappearance of a Cold Molecular Torus around the Low-luminosity Active Galactic Nucleus of NGC 1097

NASA Astrophysics Data System (ADS)

Izumi, T.; Kohno, K.; Fathi, K.; Hatziminaoglou, E.; Davies, R. I.; Martín, S.; Matsushita, S.; Schinnerer, E.; Espada, D.; Aalto, S.; Onishi, K.; Turner, J. L.; Imanishi, M.; Nakanishi, K.; Meier, D. S.; Wada, K.; Kawakatu, N.; Nakajima, T.

2017-08-01

We used the Atacama Large Millimeter/Submillimeter Array to map the CO(3-2) and the underlying continuum emissions around the type-1 low-luminosity active galactic nucleus (LLAGN; bolometric luminosity ≲ {10}42 erg s-1) of NGC 1097 at ˜10 pc resolution. These observations revealed a detailed cold gas distribution within a ˜100 pc of this LLAGN. In contrast to the luminous Seyfert galaxy NGC 1068, where a ˜7 pc cold molecular torus was recently revealed, a distinctively dense and compact torus is missing in our CO(3-2) integrated intensity map of NGC 1097. Based on the CO(3-2) flux, the gas mass of the torus of NGC 1097 would be a factor of ≳2-3 less than that found for NGC 1068 by using the same CO-to-H2 conversion factor, which implies less active nuclear star formation and/or inflows in NGC 1097. Our dynamical modeling of the CO(3-2) velocity field implies that the cold molecular gas is concentrated in a thin layer as compared to the hot gas traced by the 2.12 μm H2 emission in and around the torus. Furthermore, we suggest that NGC 1097 hosts a geometrically thinner torus than NGC 1068. Although the physical origin of the torus thickness remains unclear, our observations support a theoretical prediction that geometrically thick tori with high opacity will become deficient as AGNs evolve from luminous Seyferts to LLAGNs.

The Greenhouse Gas Emission from Portland Cement Concrete Pavement Construction in China

PubMed Central

Ma, Feng; Sha, Aimin; Yang, Panpan; Huang, Yue

2016-01-01

This study proposes an inventory analysis method to evaluate the greenhouse gas (GHG) emissions from Portland cement concrete pavement construction, based on a case project in the west of China. The concrete pavement construction process was divided into three phases, namely raw material production, concrete manufacture and pavement onsite construction. The GHG emissions of the three phases are analyzed by a life cycle inventory method. The CO2e is used to indicate the GHG emissions. The results show that for 1 km Portland cement concrete pavement construction, the total CO2e is 8215.31 tons. Based on the evaluation results, the CO2e of the raw material production phase is 7617.27 tons, accounting for 92.7% of the total GHG emissions; the CO2e of the concrete manufacture phase is 598,033.10 kg, accounting for 7.2% of the total GHG emissions. Lastly, the CO2e of the pavement onsite construction phase is 8396.59 kg, accounting for only 0.1% of the total GHG emissions. The main greenhouse gas is CO2 in each phase, which accounts for more than 98% of total emissions. N2O and CH4 emissions are relatively insignificant. PMID:27347987

Exhaust emissions of volatile organic compounds of powered two-wheelers: effect of cold start and vehicle speed. Contribution to greenhouse effect and tropospheric ozone formation.

PubMed

Costagliola, M Antonietta; Murena, Fabio; Prati, M Vittoria

2014-01-15

Powered two-wheeler (PTW) vehicles complying with recent European type approval standards (stages Euro 2 and Euro 3) were tested on chassis dynamometer in order to measure exhaust emissions of about 25 volatile organic compounds (VOCs) in the range C1-C7, including carcinogenic compounds as benzene and 1,3-butadiene. The fleet consists of a moped (engine capacity ≤ 50 cm(3)) and three fuel injection motorcycles of different engine capacities (150, 300 and 400 cm(3)). Different driving conditions were tested (US FPT cycle, constant speed). Due to the poor control of the combustion and catalyst efficiency, moped is the highest pollutant emitter. In fact, fuel injection strategy and three way catalyst with lambda sensor are able to reduce VOC motorcycles' emission of about one order of magnitude with respect to moped. Cold start effect, that is crucial for the assessment of actual emission of PTWs in urban areas, was significant: 30-51% of extra emission for methane. In the investigated speed range, moped showed a significant maximum of VOC emission factor at minimum speed (10 km/h) and a slightly decreasing trend from 20 to 60 km/h; motorcycles showed on the average a less significant peak at 10 km/h, a minimum at 30-40 km/h and then an increasing trend with a maximum emission factor at 90 km/h. Carcinogenic VOCs show the same pattern of total VOCs. Ozone Formation Potential (OFP) was estimated by using Maximum Incremental Reactivity scale. The greatest contribution to tropospheric ozone formation comes from alkenes group which account for 50-80% to the total OFP. VOC contribution effect on greenhouse effect is negligible with respect to CO2 emitted. © 2013.

Mineralogy of Sediments on a Cold and Icy Early Mars

NASA Astrophysics Data System (ADS)

Rampe, E. B.; Horgan, B. H. N.; Smith, R.; Scudder, N.; Rutledge, A. M.; Bamber, E.; Morris, R. V.

2017-12-01

The water-related minerals discovered in ancient martian terrains suggest liquid water was abundant on the surface and/or near subsurface during Mars' early history. The debate remains, however, whether these minerals are indicative of a warm and wet or cold and icy climate. To characterize mineral assemblages of cold and icy mafic terrains, we analyzed pro- and supraglacial rocks and sediments from the Collier and Diller glacial valleys in Three Sisters, Oregon. We identified primary and secondary phases using X-ray diffraction (XRD), scanning and transmission electron microscopies with energy dispersive spectroscopy (SEM, TEM, EDS), and visible/short-wave-infrared (VSWIR) and thermal-infrared (TIR) spectroscopies. Samples from both glacial valleys are dominated by primary igneous minerals (i.e., plagioclase and pyroxene). Sediments in the Collier glacial valley contain minor to trace amounts of phyllosilicates and zeolites, but these phases are likely detrital and sourced from hydrothermally altered units on North Sister. We find that the authigenic phases in cold and icy mafic terrains are poorly crystalline and/or amorphous. TEM-EDS analyses of the <2 um size fraction of glacial flour shows the presence of many different nanophase materials, including iron oxides, devitrified volcanic glass, and Fe-Si-Al (e.g., proto-clay) phases. A variety of primary and secondary amorphous materials (e.g., volcanic glass, leached glass, allophane) have been suggested from orbital IR data from Mars, and the CheMin XRD on the Curiosity rover has identified X-ray amorphous materials in all rocks and soils measured to date. The compositions of the Gale Crater amorphous components cannot be explained by primary volcanic glass alone and likely include secondary silicates, iron oxides, and sulfates. We suggest that the prevalence of amorphous materials on the martian surface and the variety of amorphous components may be a signature of a cold and icy climate on Early Mars.

Skin histology and its role in heat dissipation in three pinniped species

PubMed Central

2012-01-01

Background Pinnipeds have a thick blubber layer and may have difficulty maintaining their body temperature during hot weather when on land. The skin is the main thermoregulatory conduit which emits excessive body heat. Methods Thorough evaluation of the skin histology in three pinniped species; the California sea lion-Zalophus californianus, the Pacific harbor seal-Phoca vitulina richardsi, and the Northern elephant seal-Mirounga angustirostris, was conducted to identify the presence, location and distribution of skin structures which contribute to thermoregulation. These structures included hair, adipose tissue, sweat glands, vasculature, and arteriovenous anastomoses (AVA). Thermal imaging was performed on live animals of the same species to correlate histological findings with thermal emission of the skin. Results The presence and distribution of skin structures directly relates to emissivity of the skin in all three species. Emissivity of skin in phocids (Pacific harbor and Northern elephant seals) follows a different pattern than skin in otariids (California sea lions). The flipper skin in phocids tends to be the most emissive region during hot weather and least emissive during cold weather. On the contrary in otariids, skin of the entire body has a tendency to be emissive during both hot and cold weather. Conclusion Heat dissipation of the skin directly relates to the presence and distribution of skin structures in all three species. Different skin thermal dissipation patterns were observed in phocid versus otariid seals. Observed thermal patterns can be used for proper understanding of optimum thermal needs of seals housed in research facilities, rescue centers and zoo exhibits. PMID:22889205

Range of plasma ions in cold cluster gases near the critical point

NASA Astrophysics Data System (ADS)

Zhang, G.; Quevedo, H. J.; Bonasera, A.; Donovan, M.; Dyer, G.; Gaul, E.; Guardo, G. L.; Gulino, M.; La Cognata, M.; Lattuada, D.; Palmerini, S.; Pizzone, R. G.; Romano, S.; Smith, H.; Trippella, O.; Anzalone, A.; Spitaleri, C.; Ditmire, T.

2017-05-01

We measure the range of plasma ions in cold cluster gases by using the Petawatt laser at the University of Texas-Austin. The produced plasma propagated in all directions some hitting the cold cluster gas not illuminated by the laser. From the ratio of the measured ion distributions at different angles we can estimate the range of the ions in the cold cluster gas. It is much smaller than estimated using popular models, which take only into account the slowing down of charged particles in uniform matter. We discuss the ion range in systems prepared near a liquid-gas phase transition.

Chemical Characterization and Source Apportionment of Indoor and Outdoor Fine Particulate Matter (PM2.5) in Retirement Communities of the Los Angeles Basin

PubMed Central

Hasheminassab, Sina; Daher, Nancy; Shafer, Martin M.; Schauer, James J.; Delfino, Ralph J.; Sioutas, Constantinos

2014-01-01

Concurrent indoor and outdoor measurements of fine particulate matter (PM2.5) were conducted at three retirement homes in the Los Angeles Basin during two separate phases (cold and warm) between 2005 and 2006. Indoor-to-outdoor relationships of PM2.5 chemical constituents were determined and sources of indoor and outdoor PM2.5 were evaluated using a molecular marker-based chemical mass balance (MM-CMB) model. Indoor levels of elemental carbon (EC) along with metals and trace elements were found to be significantly affected by outdoor sources. EC, in particular, displayed very high indoor-to-outdoor (I/O) mass ratios accompanied by strong I/O correlations, illustrating the significant impact of outdoor sources on indoor levels of EC. Similarly, indoor levels of polycyclic aromatic hydrocarbons (PAHs), hopanes, and steranes were strongly correlated with their outdoor components and displayed I/O ratios close to unity. On the other hand, concentrations of n-alkanes and organic acids inside the retirement communities were dominated by indoor sources (e.g. food cooking and consumer products), as indicated by their I/O ratios, which exceeded unity. Source apportionment results revealed that vehicular emissions were the major contributor to both indoor and outdoor PM2.5, accounting for 39 and 46% of total mass, respectively. Moreover, the contribution of vehicular sources to indoor levels was generally comparable to its corresponding outdoor estimate. Other water-insoluble organic matter (other WIOM), which accounts for emissions from uncharacterized primary biogenic sources, displayed a wider range of contributions, varying from 2 to 73% of PM2.5, across all sites and phases of the study. Lastly, higher indoor than outdoor contribution of other water-soluble organic matter (other WSOM) was evident at some of the sites, suggesting the production of secondary aerosols as well as direct emissions from primary sources (including cleaning or other consumer products) at the indoor environments. PMID:24880542

Herschel HIFI GOT C+ Survey: CII, HI, and CO Emissions in a Sample of Transition Clouds and Star-Forming regions in the Inner Galaxy

NASA Astrophysics Data System (ADS)

Pineda, Jorge; Velusamy, Thangasamy; Langer, William D.; Goldsmith, Paul; Li, Di; Yorke, Harold

The GOT C+ a HIFI Herschel Key Project, studies the diffuse ISM throughout the Galactic Plane, using C+ as cloud tracer. The C+ line at 1.9 THz traces a so-far poorly studied stage in ISM cloud evolution -the transitional clouds going from atomic HI to molecular H2. This transition cloud phase, which is difficult to observe in HI and CO alone, may be best characterized via CII emission or absorption. The C+ line is also an excellent tracer of the warm diffuse gas and the warm, dense gas in the Photon Dominated Regions (PDRs). We can, therefore, use the CII emission as a probe to understand the effects of star formation on their interstellar environment. We present our first results on the transition between dense and hot gas (traced by CII) and dense and cold gas (traced by 12CO and 13CO) along a few representative lines of sight in the inner Galaxy from longitude 325 degrees to 25 degrees, taken during the HIFI Priority Science Phase. Comparisons of the high spectral resolution ( 1 km/s) HIFI data on C+ with HI, 12CO, and 13CO spectra allow us to separate out the different ISM components along each line of sight. Our results provide detailed information about the transition of diffuse atomic to molecular gas clouds needed to understand star formation and the lifecycle of the interstellar gas. These observations are being carried out with the Herschel Space Observatory, which is an ESA cornerstone mission, with contributions from NASA. This research was conducted at the Jet Propulsion Laboratory, California Institute of Technology under contract with the National Aeronautics and Space Administration. JLP was supported under the NASA Postdoctoral Program at JPL, Caltech, administered by Oak Ridge Associated Universities through a contract with NASA, and is currently supported as a Caltech-JPL Postdoctoral associate.

Treatment of enterococcus faecalis bacteria by a helium atmospheric cold plasma brush with oxygen addition

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

Chen Wei; Huang Jun; Wang Xingquan

2012-07-01

An atmospheric cold plasma brush suitable for large area and low-temperature plasma-based sterilization is designed. Results demonstrate that the He/O{sub 2} plasma more effectively kills Enterococcus faecalis than the pure He plasma. In addition, the sterilization efficiency values of the He/O{sub 2} plasma depend on the oxygen fraction in Helium gas. The atmospheric cold plasma brush using a proper ratio of He/O{sub 2} (2.5%) reaches the optimum sterilization efficiency. After plasma treatment, the cell structure and morphology changes can be observed by the scanning electron microscopy. Optical emission measurements indicate that reactive species such as O and OH play amore » significant role in the sterilization process.« less

Chemistry of Protostellar Envelopes and Disks

NASA Astrophysics Data System (ADS)

Flores Rivera, Lizxandra; Terebey, Susan; Willacy, Karen

2018-06-01

Molecule formation is dynamic during the protostar collapse phase, driven by changes in temperature, density, and UV radiation as gas and dust flows from the envelope onto the forming protoplanetary disk. In this work, we compare physical models based on two different collapse solutions. We modeled the chemistry (created by Karen Willacy) for C18O to see how its abundance changes over time using as primary input parameters the temperature and density profile that were produced by the dust Radiative Transfer (MCRT) model called HOCHUNK3D from Whitney (2003). Given this model, we produce synthetic line emission maps from L1527 IRS to simulate the Class 0/I protostar L1527 IRS using RADMC3D code and compare them with previous observations from ALMA. High concentrations of gas phase molecules of C18O are found within the 20 AU in areas in the envelope that are close to the surface of the disk. In the outermost part of the disk surface, the C18O freezes out beyond 400 AU, showing a much reduced abundance where the temperature profile drops down below 25 K. In cold regions, the radiation field plays an important role in the chemistry.

Herschel Sees Through Ghostly Pillars

NASA Image and Video Library

2012-01-18

This image of the Eagle nebula shows the self-emission of the intensely cold nebula gas and dust as never seen before; the nebula intricate tendril nature, with vast cavities forms an almost cave-like surrounding to the famous pillars.

REDUCING REFRIGERANT EMISSIONS FROM SUPERMARKET SYSTEMS

EPA Science Inventory

Large refrigeration systems are found in several applications including supermarkets, cold storage warehouses, and industrial processes. The sizes of these systems are a contributing factor to their problems of high refrigerant leak rates because of the thousands of connections, ...

Dimensional crossover and cold-atom realization of topological Mott insulators

PubMed Central

Scheurer, Mathias S.; Rachel, Stephan; Orth, Peter P.

2015-01-01

Interacting cold-atomic gases in optical lattices offer an experimental approach to outstanding problems of many body physics. One important example is the interplay of interaction and topology which promises to generate a variety of exotic phases such as the fractionalized Chern insulator or the topological Mott insulator. Both theoretically understanding these states of matter and finding suitable systems that host them have proven to be challenging problems. Here we propose a cold-atom setup where Hubbard on-site interactions give rise to spin liquid-like phases: weak and strong topological Mott insulators. They represent the celebrated paradigm of an interacting and topological quantum state with fractionalized spinon excitations that inherit the topology of the non-interacting system. Our proposal shall help to pave the way for a controlled experimental investigation of this exotic state of matter in optical lattices. Furthermore, it allows for the investigation of a dimensional crossover from a two-dimensional quantum spin Hall insulating phase to a three-dimensional strong topological insulator by tuning the hopping between the layers. PMID:25669431

The chilling truth about the solar chromosphere

NASA Astrophysics Data System (ADS)

Ayres, Thomas R.

The notion that much of the solar gas in the low chromosphere is cool is discussed in terms of its validity. The dark CO absorption cores recorded at the extreme limb of the sun are described, including the 3-2 R14 line with a core-brightness temperature of 3620 K. A bifurcation in the plasma energy balance described to explain the high altitude cold gas is reviewed in terms of recent investigations. Spectral simulations of CO are described which examine the range of thermal profiles allowed by CO observations with low spatial resolution and limb darkening. Weak emission shoulders in the K line demonstrate that a cool chromosphere with Ca II emission is feasible, although the cold gas requires a surface coverage of as little as 20 percent to reproduce the limb darkening. To distinguish between the thermal bifurcation notion and the neophotosphere concept, observations of the high spatial resolution spectra of the CO bands are required.

Thin films of aluminum nitride and aluminum gallium nitride for cold cathode applications

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

Sowers, A.T.; Christman, J.A.; Bremser, M.D.

1997-10-01

Cold cathode structures have been fabricated using AlN and graded AlGaN structures (deposited on n-type 6H-SiC) as the thin film emitting layer. The cathodes consist of an aluminum grid layer separated from the nitride layer by a SiO{sub 2} layer and etched to form arrays of either 1, 3, or 5 {mu}m holes through which the emitting nitride surface is exposed. After fabrication, a hydrogen plasma exposure was employed to activate the cathodes. Cathode devices with 5 {mu}m holes displayed emission for up to 30 min before failing. Maximum emission currents ranged from 10{endash}100 nA and required grid voltages rangingmore » from 20{endash}110 V. The grid currents were typically 1 to 10{sup 4} times the collector currents. {copyright} {ital 1997 American Institute of Physics.}« less

Kinetic modeling on CO₂ capture using basic oxygen furnace slag coupled with cold-rolling wastewater in a rotating packed bed.

PubMed

Chang, E-E; Chen, Tse-Lun; Pan, Shu-Yuan; Chen, Yi-Hung; Chiang, Pen-Chi

2013-09-15

In this study, direct and indirect carbonation of basic oxygen furnace slag (BOFS) coupled with cold-rolling wastewater (CRW) was carried out via a rotating packed bed (RPB). The solid products were qualitatively characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) and quantitatively analyzed with thermogravimetric analysis (TGA). The leachate was analyzed with inductively coupled plasma-optical emission spectroscopy (ICP-OES). The results indicate that the maximum achievable carbonation conversion (MACC) of BOFS was 90.7%, corresponding to a capture capacity of 0.277 g CO₂/g of BOFS, by direct carbonation with CRW under a rotation speed of 750 rpm at 30 °C for 20 min. In addition, CO₂ mass balance among the gas, liquid, and solid phases within an RPB was well-developed, with an error less than 10%, to confirm the actual CO₂ capture capacity of BOFS with precision and accuracy. Furthermore, a reaction kinetic model based on mass balance was established to determine the reaction rate constant for various liquid agents (CRW and pure water). It was concluded that co-utilization of alkaline wastes including BOFS and CRW via the RPB is a novel approach for both enhancing CO₂ capture capacity and reducing the environmental impacts of alkaline wastes. Copyright © 2013 Elsevier B.V. All rights reserved.

Laser Induced Fluorescence Spectroscopy of Neutral and Ionized Polycyclic Aromatic Hydrocarbons in the Cosmic Simulation Chamber

NASA Technical Reports Server (NTRS)

Bejaoui, Salma; Salama, Farid; Contreras, Cesar; Sciamma O'Brien, Ella; Foing, Bernard; Pascale, Ehrenfreund

2015-01-01

Polycyclic aromatic hydrocarbon (PAH) molecules are considered the best carriers to account for the ubiquitous infrared emission bands. PAHs have also been proposed as candidates to explain the diffuse interstellar bands (DIBs), a series of absorption features seen on the interstellar extinction curve and are plausible carriers for the extended red emission (ERE), a photoluminescent process associated with a wide variety of interstellar environments. Extensive efforts have been devoted over the past two decades to characterize the physical and chemical properties of PAH molecules and ions in space. Absorption spectra of PAH molecules and ions trapped in solid matrices have been compared to the DIBs. Absorption spectra of several cold, isolated gas-phase PAHs have also been measured under experimental conditions that mimic the interstellar conditions. The purpose of this study is to provide a new dimension to the existing spectroscopic database of neutral and single ionized PAHs that is largely based on absorption spectra by adding emission spectroscopy data. The measurements are based on the laser induced fluorescence (LIF) technique and are performed with the Pulsed Discharge Nozzle (PDN) of the COSmIC laboratory facility at NASA Ames laboratory. The PDN generates a plasma in a free supersonic jet expansion to simulate the physical and the chemical conditions in interstellar environments. We focus, here, on the fluorescence spectra of large neutral PAHs and their cations where there is a lack of fluorescence spectroscopy data. The astronomical implications of the data (e.g., ERE) are examined.

Polycyclic Aromatic Hydrocarbons

NASA Technical Reports Server (NTRS)

Salama, Farid

2010-01-01

Carbonaceous materials play an important role in space. Polycyclic Aromatic Hydrocarbons (PAHs) are a ubiquitous component of the carbonaceous materials. PAHs are the best-known candidates to account for the IR emission bands. They are also thought to be among the carriers of the diffuse interstellar absorption bands (DIBs). PAH ionization states reflect the ionization balance of the medium while PAH size, composition, and structure reflect the energetic and chemical history of the medium. A major challenge is to reproduce in the laboratory the physical conditions that exist in the emission and absorption interstellar zones. The harsh physical conditions of the ISM -low temperature, collisionless, strong UV radiation fields- are simulated in the laboratory by associating a molecular beam with an ionizing discharge to generate a cold plasma expansion. PAH ions and radicals are formed from the neutral precursors in an isolated environment at low temperature and probed with high-sensitivity cavity ringdown spectroscopy in the NUV-NIR range. Carbon nanoparticles are also formed during the short residence time of the precursors in the plasma and are characterized with time-offlight mass spectrometry. These experiments provide unique information on the spectra of large carbonaceous molecules and ions in the gas phase that can now be directly compared to interstellar and circumstellar observations (IR emission bands, DIBs, extinction curve). These findings also hold great potential for understanding the formation process of interstellar carbonaceous grains. We will review recent progress in the experimental and theoretical studies of PAHs, compare the laboratory data with astronomical observations and discuss the global implications.

The Redox Potential of the Plastoquinone Pool of the Cyanobacterium Synechocystis Species Strain PCC 6803 Is under Strict Homeostatic Control1[C][W

PubMed Central

Schuurmans, R. Milou; Schuurmans, J. Merijn; Bekker, Martijn; Kromkamp, Jacco C.; Matthijs, Hans C.P.; Hellingwerf, Klaas J.

2014-01-01

A method is presented for rapid extraction of the total plastoquinone (PQ) pool from Synechocystis sp. strain PCC 6803 cells that preserves the in vivo plastoquinol (PQH2) to -PQ ratio. Cells were rapidly transferred into ice-cold organic solvent for instantaneous extraction of the cellular PQ plus PQH2 content. After high-performance liquid chromatography fractionation of the organic phase extract, the PQH2 content was quantitatively determined via its fluorescence emission at 330 nm. The in-cell PQH2-PQ ratio then followed from comparison of the PQH2 signal in samples as collected and in an identical sample after complete reduction with sodium borohydride. Prior to PQH2 extraction, cells from steady-state chemostat cultures were exposed to a wide range of physiological conditions, including high/low availability of inorganic carbon, and various actinic illumination conditions. Well-characterized electron-transfer inhibitors were used to generate a reduced or an oxidized PQ pool for reference. The in vivo redox state of the PQ pool was correlated with the results of pulse-amplitude modulation-based chlorophyll a fluorescence emission measurements, oxygen exchange rates, and 77 K fluorescence emission spectra. Our results show that the redox state of the PQ pool of Synechocystis sp. strain PCC 6803 is subject to strict homeostatic control (i.e. regulated between narrow limits), in contrast to the more dynamic chlorophyll a fluorescence signal. PMID:24696521

Wave-Particle Interactions Involving Correlated Electron Bursts and Whistler Chorus in Earth's Radiation Belts

NASA Astrophysics Data System (ADS)

Echterling, N.; Schriver, D.; Roeder, J. L.; Fennell, J. F.

2017-12-01

During the recovery phase of substorm plasma injections, the Van Allen Probes commonly observe events of quasi-periodic energetic electron bursts correlating with simultaneously detected upper-band, whistler-mode chorus emissions. These electron bursts exhibit narrow ranges of pitch angles (75-80° and 100-105°) and energies (20-40 keV). Electron cyclotron harmonic (ECH) emissions are also commonly detected, but typically do not display correlation with the electron bursts. To examine sources of free energy and the generation of these wave emissions, an observed electron velocity distribution on January 13, 2013 is used as the starting condition for a particle in cell (PIC) simulation. Effects of temperature anisotropy (perpendicular temperature greater than parallel temperature), the presence of a loss cone and a cold electron population on the generation of whistler and ECH waves are examined to understand wave generation and nonlinear interactions with the particle population. These nonlinear interactions produce energy diffusion along with strong pitch angle scattering into the loss cone on the order of milliseconds, which is faster than a typical bounce period of seconds. To examine the quasi-periodic nature of the electron bursts, a loss-cone recycling technique is implemented to model the effects of the periodic emptying of the loss cone and electron injection on the growth of whistler and ECH waves. The results of the simulations are compared to the Van Allen Probe observations to determine electron acceleration, heating and transport in Earth's radiation belts due to wave-particle interactions.

Can Hail and Rain Nucleate Cloud Droplets?

NASA Astrophysics Data System (ADS)

Weiss, S.; Prabhakaran, P.; Krekhov, A.; Pumir, A.; Bodenschatz, E.

2017-12-01

We present results from a laboratory scale moist convection experiment composed of a mixture of pressurized sulphur hexafluoride (SF6 - liquid and vapor phase) and helium (He - gas phase) to mimic the wet (saturated water vapor) and dry components (nitrogen, oxygen etc.) of the earth's atmosphere. We operate the experiments close to critical conditions to allow for homogeneous nucleation of sulphur hexafluoride droplets. The liquid SF6 pool is heated from below and the warm SF6 vapor from the liquid-vapor interface rise and condense underneath the cold top plate. We observe the nucleation of microdroplets in the wake of cold drops falling through the SF6-He atmosphere. Using classical nucleation theory, we show that the nucleation is caused by isobaric cooling of SF6 vapor in the wake of the cold drop. Furthermore, we argue that in an atmospheric cloud, falling hail and large cold raindrops may induce heterogeneous nucleation of microdroplets in their wake. We also observe that under appropriate conditions these microdroplets form a stable horizontal layer, thus separating regions of super and sub-critical saturation.

Can hail and rain nucleate cloud droplets?

NASA Astrophysics Data System (ADS)

Prabhakaran, Prasanth; Weiss, Stephan; Krekhov, Alexei; Pumir, Alain; Bodenschatz, Eberhard

2017-11-01

We present results from a laboratory scale moist convection experiment composed of a mixture of pressurized sulphur hexafluoride (SF6 - liquid and vapor phase) and helium (He - gas phase) to mimic the wet (saturated water vapor) and dry components (nitrogen, oxygen etc.) of the earth's atmosphere. We operate the experiments close to critical conditions to allow for homogeneous nucleation of sulphur hexafluoride droplets. The liquid SF6 pool is heated from below and the warm SF6 vapor from the liquid-vapor interface rise and condense underneath the cold top plate. We observe the nucleation of microdroplets in the wake of cold drops falling through the SF6-He atmosphere. Using classical nucleation theory, we show that the nucleation is caused by isobaric cooling of SF6 vapor in the wake of the cold drop. Furthermore, we argue that in an atmospheric cloud, falling hail and large cold raindrops may induce heterogeneous nucleation of microdroplets in their wake. We also observe that under appropriate conditions these microdroplets form a stable horizontal layer, thus separating regions of super and sub-critical saturation.

Resonant Pump-dump Quantum Control of Solvated Dye Molecules with Phase Jumps

NASA Astrophysics Data System (ADS)

Konar, Arkaprabha; Lozovoy, Vadim; Dantus, Marcos

2014-03-01

Quantum coherent control of two photon and multiphoton excitation processes in atomic and condensed phase systems employing phase jumps has been well studied and understood. Here we demonstrate coherent quantum control of a two photon resonant pump-dump process in a complex solvated dye molecule. Phase jump in the frequency domain via a pulse shaper is employed to coherently enhance the stimulated emission by an order of magnitude when compared to transform limited pulses. Red shifted stimulated emission from successive low energy Stokes shifted excited states leading to narrowband emission are observed upon scanning the pi step across the excitation spectrum. A binary search space routine was also employed to investigate the effects of other types of phase jumps on stimulated emission and to determine the optimum phase that maximizes the emission. Understanding the underlying mechanism of this kind of enhancement will guide us in designing pulse shapes for enhancing stimulated emission, which can be further applied in the field of imaging.

Emission of intermediate, semi and low volatile organic compounds from traffic and their impact on secondary organic aerosol concentrations over Greater Paris

NASA Astrophysics Data System (ADS)

Sartelet, K.; Zhu, S.; Moukhtar, S.; André, M.; André, J. M.; Gros, V.; Favez, O.; Brasseur, A.; Redaelli, M.

2018-05-01

Exhaust particle emissions are mostly made of black carbon and/or organic compounds, with some of these organic compounds existing in both the gas and particle phases. Although emissions of volatile organic compounds (VOC) are usually measured at the exhaust, emissions in the gas phase of lower volatility compounds (POAvapor) are not. However, these gas-phase emissions may be oxidised after emission and enhance the formation of secondary organic aerosols (SOA). They are shown here to contribute to most of the SOA formation in Central Paris. POAvapor emissions are usually estimated from primary organic aerosol emissions in the particle phase (POA). However, they could also be estimated from VOC emissions for both gasoline and diesel vehicles using previously published measurements from chamber measurements. Estimating POAvapor from VOC emissions and ageing exhaust emissions with a simple model included in the Polyphemus air-quality platform compare well to measurements of SOA formation performed in chamber experiments. Over Greater Paris, POAvapor emissions estimated using POA and VOC emissions are compared using the HEAVEN bottom-up traffic emissions model. The impact on the simulated atmospheric concentrations is then assessed using the Polyphemus/Polair3D chemistry-transport model. Estimating POAvapor emissions from VOC emissions rather than POA emissions lead to lower emissions along motorway axes (between -50% and -70%) and larger emissions in urban areas (up to between +120% and +140% in Central Paris). The impact on total organic aerosol concentrations (gas plus particle) is lower than the impact on emissions: between -8% and 25% along motorway axes and in urban areas respectively. Particle-phase organic concentrations are lower when POAvapor emissions are estimated from VOC than POA emissions, even in Central Paris where the total organic aerosol concentration is higher, because of different assumptions on the emission volatility distribution, stressing the importance of characterizing not only the emission strength, but also the emission volatility distribution.

Crystallographic and magnetic structure of HAVAR under high-pressure using diamond anvil cell (DAC)

NASA Astrophysics Data System (ADS)

Halevy, Itzhak; Haroush, Shlomo; Eisen, Yosef; Silberman, Ido; Moreno, Dany; Hen, Amir; Winterrose, Mike L.; Ghose, Sanjit; Chen, Zhiqiang

2010-04-01

Annealed (H1) and cold-rolled (H2) HAVAR has been studied using high-pressure synchrotron X-ray diffraction. A structural phase transformation was discovered at ˜13 GPa at ambient temperature, transforming from m - 3 m (S.G. 225) to P 63/m m c (S.G. 194) symmetry. The transition was not reversible on pressure release. The low-pressure cubic phase was found to be more compressible than the high-pressure hexagonal phase. Conventional Mössbauer and NFS shows that the HAVAR is not magnetic at room temperature and no splitting is observed. The SQUID indicates a huge difference in the temperature dependence of the magnetic susceptibility between the cold Rolled HAVAR compared to the annealed HAVAR.

Effect of the estrous cycle on water maze acquisition depends on the temperature of the water.

PubMed

Rubinow, Marisa J; Arseneau, Linda M; Beverly, J Lee; Juraska, Janice M

2004-08-01

The literature on the effects of ovarian hormones on rodent learning and memory is mixed. In this study, the authors examined the role of task stressfulness. Female hooded rats were tested during proestrus or estrus on the hidden-platform water maze in warm (33 degrees C) or cold (19 degrees C) water. There were no effects of cycle or temperature, but estrous phase interacted with temperature such that proestrous rats performed better overall under the warm condition and estrous rats performed better under the cold condition. Plasma corticosterone, measured after 4 trials, varied significantly with estrous phase. Water temperature, perhaps through stress, influences the effect of estrous phase on water maze performance.

Condensed-phase biogenic-anthropogenic interactions with implications for cold cloud formation

DOE PAGES

Charnawskas, Joseph C.; Alpert, Peter A.; Lambe, Andrew; ...

2017-01-24

Anthropogenic and biogenic gas emissions contribute to the formation of secondary organic aerosol (SOA). When present, soot particles from fossil-fuel combustion can acquire a coating of SOA. We investigate SOA-soot biogenic-anthropogenic interactions and their impact on ice nucleation in relation to the particles’ organic phase state. SOA particles were generated from the OH oxidation of naphthalene, α-pinene, longifolene, or isoprene, with or without presence of sulfate or soot particles. Corresponding particle glass transition (T g) and full deliquescence relative humidity (FDRH) were estimated by a numerical diffusion model. Longifolene SOA particles are solid-like and all biogenic SOA sulfate mixtures exhibitmore » a core-shell configuration (i.e. a sulfate-rich core coated with SOA). Biogenic SOA with or without sulfate formed ice at conditions expected for homogeneous ice nucleation in agreement with respective T g and FDRH. α-pinene SOA coated soot particles nucleated ice above the homogeneous freezing temperature with soot acting as ice nuclei (IN). At lower temperatures the α-pinene SOA coating can be semisolid inducing ice nucleation. Naphthalene SOA coated soot particles acted as IN above and below the homogeneous freezing limit, which can be explained by the presence of a highly viscous SOA phase. Our results suggest that biogenic SOA does not play a significant role in mixed-phase cloud formation and the presence of sulfate further renders this even less likely. Furthermore, anthropogenic SOA may have an enhancing effect on cloud glaciation under mixed-phase and cirrus cloud conditions compared to biogenic SOA that dominate during preindustrial times or in pristine areas.« less

Condensed-phase biogenic–anthropogenic interactions with implications for cold cloud formation

DOE PAGES

Charnawskas, Joseph C.; Alpert, Peter A.; Lambe, Andrew T.; ...

2017-01-24

Anthropogenic and biogenic gas emissions contribute to the formation of secondary organic aerosol (SOA). When present, soot particles from fossil fuel combustion can acquire a coating of SOA. We investigate SOA–soot biogenic–anthropogenic interactions and their impact on ice nucleation in relation to the particles’ organic phase state. SOA particles were generated from the OH oxidation of naphthalene, α-pinene, longifolene, or isoprene, with or without the presence of sulfate or soot particles. Corresponding particle glass transition (T g) and full deliquescence relative humidity (FDRH) were estimated using a numerical diffusion model. Longifolene SOA particles are solid-like and all biogenic SOA sulfatemore » mixtures exhibit a core–shell configuration (i.e.a sulfate-rich core coated with SOA). Biogenic SOA with or without sulfate formed ice at conditions expected for homogeneous ice nucleation, in agreement with respectiveT gand FDRH. α-pinene SOA coated soot particles nucleated ice above the homogeneous freezing temperature with soot acting as ice nuclei (IN). At lower temperatures the α-pinene SOA coating can be semisolid, inducing ice nucleation. Naphthalene SOA coated soot particles acted as ice nuclei above and below the homogeneous freezing limit, which can be explained by the presence of a highly viscous SOA phase. Our results suggest that biogenic SOA does not play a significant role in mixed-phase cloud formation and the presence of sulfate renders this even less likely. However, anthropogenic SOA may have an enhancing effect on cloud glaciation under mixed-phase and cirrus cloud conditions compared to biogenic SOA that dominate during pre-industrial times or in pristine areas.« less

Condensed-phase biogenic-anthropogenic interactions with implications for cold cloud formation.

PubMed

Charnawskas, Joseph C; Alpert, Peter A; Lambe, Andrew T; Berkemeier, Thomas; O'Brien, Rachel E; Massoli, Paola; Onasch, Timothy B; Shiraiwa, Manabu; Moffet, Ryan C; Gilles, Mary K; Davidovits, Paul; Worsnop, Douglas R; Knopf, Daniel A

2017-08-24

Anthropogenic and biogenic gas emissions contribute to the formation of secondary organic aerosol (SOA). When present, soot particles from fossil fuel combustion can acquire a coating of SOA. We investigate SOA-soot biogenic-anthropogenic interactions and their impact on ice nucleation in relation to the particles' organic phase state. SOA particles were generated from the OH oxidation of naphthalene, α-pinene, longifolene, or isoprene, with or without the presence of sulfate or soot particles. Corresponding particle glass transition (T g ) and full deliquescence relative humidity (FDRH) were estimated using a numerical diffusion model. Longifolene SOA particles are solid-like and all biogenic SOA sulfate mixtures exhibit a core-shell configuration (i.e. a sulfate-rich core coated with SOA). Biogenic SOA with or without sulfate formed ice at conditions expected for homogeneous ice nucleation, in agreement with respective T g and FDRH. α-pinene SOA coated soot particles nucleated ice above the homogeneous freezing temperature with soot acting as ice nuclei (IN). At lower temperatures the α-pinene SOA coating can be semisolid, inducing ice nucleation. Naphthalene SOA coated soot particles acted as ice nuclei above and below the homogeneous freezing limit, which can be explained by the presence of a highly viscous SOA phase. Our results suggest that biogenic SOA does not play a significant role in mixed-phase cloud formation and the presence of sulfate renders this even less likely. However, anthropogenic SOA may have an enhancing effect on cloud glaciation under mixed-phase and cirrus cloud conditions compared to biogenic SOA that dominate during pre-industrial times or in pristine areas.

Effect of temperature, water-phase salt and phenolic contents on Listeria monocytogenes growth rates on cold-smoked salmon and evaluation of secondary models.

PubMed

Cornu, M; Beaufort, A; Rudelle, S; Laloux, L; Bergis, H; Miconnet, N; Serot, T; Delignette-Muller, M L

2006-02-01

Salting and smoking are ancient processes for fish preservation. The effects of salt and phenolic smoke compounds on the growth rate of L. monocytogenes in cold-smoked salmon were investigated through physico-chemical analyses, challenge tests on surface of cold-smoked salmon at 4 degrees C and 8 degrees C, and a survey of the literature. Estimated growth rates were compared to predictions of existing secondary models, taking into account the effects of temperature, water phase salt content, phenolic content, and additional factors (e.g. pH, lactate, dissolved CO2). The secondary model proposed by Devlieghere et al. [Devlieghere, F., Geeraerd, A.H., Versyck, K.J., Vandewaetere, B., van Impe, J., Debevere, J., 2001. Growth of Listeria monocytogenes in modified atmosphere packed cooked meat products: a predictive model. Food Microbiology 18, 53-66.] and modified by Giménez and Dalgaard [Giménez, B., Dalgaard, P., 2004. Modelling and predicting the simultaneous growth of Listeria monocytogenes and spoilage micro-organisms in cold-smoked salmon. Journal of Applied Microbiology 96, 96-109.] appears appropriate. However, further research is needed to understand all effects affecting growth of L. monocytogenes in cold-smoked salmon and to obtain fully validated predictive models for use in quantitative risk assessment.

Variability of cold season surface air temperature over northeastern China and its linkage with large-scale atmospheric circulations

NASA Astrophysics Data System (ADS)

Zhuang, Yuanhuang; Zhang, Jingyong; Wang, Lin

2018-05-01

Cold temperature anomalies and extremes have profound effects on the society, the economy, and the environment of northeastern China (NEC). In this study, we define the cold season as the months from October to April, and investigate the variability of cold season surface air temperature (CSAT) over NEC and its relationships with large-scale atmospheric circulation patterns for the period 1981-2014. The empirical orthogonal function (EOF) analysis shows that the first EOF mode of the CSAT over NEC is characterized by a homogeneous structure that describes 92.2% of the total variance. The regionally averaged CSAT over NEC is closely linked with the Arctic Oscillation ( r = 0.62, 99% confidence level) and also has a statistically significant relation with the Polar/Eurasian pattern in the cold season. The positive phases of the Arctic Oscillation and the Polar/Eurasian pattern tend to result in a positive geopotential height anomaly over NEC and a weakened East Asian winter monsoon, which subsequently increase the CSAT over NEC by enhancing the downward solar radiation, strengthening the subsidence warming and warm air advection. Conversely, the negative phases of these two climate indices result in opposite regional atmospheric circulation anomalies and decrease the CSAT over NEC.

On the Method of Efficient Ice Cold Energy Storage Using a Heat Transfer of Direct Contact Phase Change and a Natural Circulation of a Working Medium in an Enclosure

NASA Astrophysics Data System (ADS)

Utaka, Yoshio; Saito, Akio; Nakata, Naoki

The objectives of this report are to propose a new method of the high performance cold energy storage using ice as a phase change material and to clarify the heat transfer characteristics of the apparatus of ice cold energy storage based on the proposed principle. A working medium vapor layer a water layer and a working medium liquid layer stratified in this order from the top were kept in an enclosure composed of a condenser, an evaporator and a condensate receiver-and-return tube. The direct contact heat transfers between water or ice and a working medium in an enclosure were applied for realizing the high performance cold energy storage and release. In the storage and release processes, water changes the phase between the liquid and the solid, and the working medium cnanges between the vapor and the liquid with a natural circulation. Experimental apparatus was manufactured and R12 and R114 were selected as working media in the thermal energy storage enclosure. It was confirmed by the measurements that the efficient formation and melting of ice were achieved. Then, th e heat transfer characteristics were clarified for the effects of the initial water height, the initial height of woking medium liquid layer and the inlet coolant temperature.

Characteristics of black carbon emissions from in-use light-duty passenger vehicles.

PubMed

Zheng, Xuan; Zhang, Shaojun; Wu, Ye; Zhang, K Max; Wu, Xian; Li, Zhenhua; Hao, Jiming

2017-12-01

Mitigating black carbon (BC) emissions from various combustion sources has been considered an urgent policy issue to address the challenges of climate change, air pollution and health risks. Vehicles contribute considerably to total anthropogenic BC emissions and urban BC concentrations. Compared with heavy-duty diesel vehicles, there is much larger uncertainty in BC emission factors for light-duty passenger vehicles (LDPVs), in particular for gasoline LDPVs, which warrants further studies. In this study, we employed the dynamometer and the Aethalometer (AE-51) to measure second-by-second BC emissions from eight LDPVs by engine technology and driving cycle. The average BC emission factors under transient cycles (e.g., ECE-15, New European Driving Cycle, NEDC, Worldwide Harmonized Light Vehicles Test Cycle, WLTC) are 3.6-91.5 mg/km, 7.6 mg/km and 0.13-0.58 mg/km, respectively, for diesel (N = 3), gasoline direct injection (GDI) (N = 1) and gasoline port-fuel injection (PFI) engine categories (N = 4). For gasoline PFI LDPVs, the instantaneous emission profiles show a strong association of peak BC emissions with cold-start and high-speed aggressive driving. Such impacts lead to considerable BC emission contributions in cold-start periods (e.g., the first 47 s-94 s) over the entire cycle (e.g., 18-76% of the NEDC and 13-36% of the WLTC) and increased BC emission factors by 80-440% under the WLTC compared to the NEDC. For diesel BC emissions, the size distribution exhibits a typical unimodal pattern with one single peak appearing approximately from 120 to 150 nm, which is largely consistent with previous studies. Nevertheless, the average mass ratios of BC to particle mass (PM) range from 0.38 to 0.54 for three diesel samples, representing substantial impacts from both driving and engine conditions. The significant discrepancy between gasoline BC emission factors obtained from tailpipe exhaust versus ambient conditions suggest that more comparative measurements and fine-grained simulations should be designed and implemented to address this discrepancy. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Planck Catalogue of Galactic Cold Clumps : Looking at the early stages of star-formation

NASA Astrophysics Data System (ADS)

Montier, Ludovic

2015-08-01

The Planck satellite has provided an unprecedented view of the submm sky, allowing us to search for the dust emission of Galactic cold sources. Combining Planck-HFI all-sky maps in the high frequency channels with the IRAS map at 100um, we built the Planck catalogue of Galactic Cold Clumps (PGCC, Planck 2015 results XXVIII 2015), counting 13188 sources distributed over the whole sky, and following mainly the Galactic structures at low and intermediate latitudes. This is the first all-sky catalogue of Galactic cold sources obtained with a single instrument at this resolution and sensitivity, which opens a new window on star-formation processes in our Galaxy.I will briefly describe the colour detection method used to extract the Galactic cold sources, i.e., the Cold Core Colour Detection Tool (CoCoCoDeT, Montier et al. 2010), and its application to the Planck data. I will discuss the statistical distribution of the properties of the PGCC sources (in terms of dust temperature, distance, mass, density and luminosity), which illustrates that the PGCC catalogue spans a large variety of environments and objects, from molecular clouds to cold cores, and covers various stages of evolution. The Planck catalogue is a very powerful tool to study the formation and the evolution of prestellar objects and star-forming regions.I will finally present an overview of the Herschel Key Program Galactic Cold Cores (PI. M.Juvela), which allowed us to follow-up about 350 Planck Galactic Cold Clumps, in various stages of evolution and environments. With this program, the nature and the composition of the 5' Planck sources have been revealed at a sub-arcmin resolution, showing very different configurations, such as starless cold cores or multiple Young Stellar objects still embedded in their cold envelope.

Enantiomer-Selective Photo-Induced Reaction of Protonated Tryptophan with Disaccharides in the Gas Phase

NASA Astrophysics Data System (ADS)

Doan, Thuc N.; Fujihara, Akimasa

2018-03-01

In order to investigate chemical evolution in interstellar molecular clouds, enantiomer-selective photo-induced chemical reactions between an amino acid and disaccharides in the gas phase were examined using a tandem mass spectrometer containing an electrospray ionization source and a cold ion trap. Ultraviolet photodissociation mass spectra of cold gas-phase noncovalent complexes of protonated tryptophan (Trp) enantiomers with disaccharides consisting of two d-glucose units, such as d-maltose or d-cellobiose, were obtained by photoexcitation of the indole ring of Trp. NH2CHCOOH loss via cleavage of the Cα-Cβ bond in Trp induced by hydrogen atom transfer from the NH3 + group of a protonated Trp was observed in a noncovalent heterochiral H+( l-Trp)( d-maltose) complex. In contrast, a photo-induced chemical reaction forming the product ion with m/z 282 occurs in homochiral H+( d-Trp)( d-maltose). For d-cellobiose, both NH2CHCOOH elimination and the m/z 282 product ion were observed, and no enantiomer-selective phenomena occurred. The m/z 282 product ion indicates that the photo-induced C-glycosylation, which links d-glucose residues to the indole moiety of Trp via a C-C bond, can occur in cold gas-phase noncovalent complexes, and its enantiomer-selectivity depends on the structure of the disaccharide.

Spin temperature and density of cold and warm H I in the Galactic disk: Hidden H I

NASA Astrophysics Data System (ADS)

Sofue, Yoshiaki

2018-05-01

We present a method to determine the spin temperature TS and volume density n of H I gas simultaneously along the tangent-point circle of Galactic rotation in the Milky Way by using the χ2 method. The best-fit TS is shown to range either in TS ˜ 100-120 K or in 1000-3000 K, indicating that the gas is in the cold H I phase with high density and large optical depth, or in warm H I with low density and small optical depth. Averaged values at 3 ≤ R ≤ 8 kpc are obtained to be TS = 106.7 ± 16.0 K and n = 1.53 ± 0.86 H cm-3 for cold H I, and 1720 ± 1060 K and 0.38 ± 0.10 H cm-3 for warm H I, where R = 8 |sinl| kpc is the galacto-centric distance along the tangent-point circle. The cold H I appears in spiral arms and rings, whereas warm H I appears in the inter-arm regions. The cold H I is denser by a factor of ˜4 than warm H I. The present analysis has revealed the hidden H I mass in the cold and optically thick phase in the Galactic disk. The total H I mass inside the solar circle is shown to be greater by a factor of 2-2.5 than the current estimation by the optically thin assumption.

Spin temperature and density of cold and warm H I in the Galactic disk: Hidden H I

NASA Astrophysics Data System (ADS)

Sofue, Yoshiaki

2018-06-01

We present a method to determine the spin temperature TS and volume density n of H I gas simultaneously along the tangent-point circle of Galactic rotation in the Milky Way by using the χ2 method. The best-fit TS is shown to range either in TS ˜ 100-120 K or in 1000-3000 K, indicating that the gas is in the cold H I phase with high density and large optical depth, or in warm H I with low density and small optical depth. Averaged values at 3 ≤ R ≤ 8 kpc are obtained to be TS = 106.7 ± 16.0 K and n = 1.53 ± 0.86 H cm-3 for cold H I, and 1720 ± 1060 K and 0.38 ± 0.10 H cm-3 for warm H I, where R = 8 |sinl| kpc is the galacto-centric distance along the tangent-point circle. The cold H I appears in spiral arms and rings, whereas warm H I appears in the inter-arm regions. The cold H I is denser by a factor of ˜4 than warm H I. The present analysis has revealed the hidden H I mass in the cold and optically thick phase in the Galactic disk. The total H I mass inside the solar circle is shown to be greater by a factor of 2-2.5 than the current estimation by the optically thin assumption.

Galactic cold cores. VI. Dust opacity spectral index

NASA Astrophysics Data System (ADS)

Juvela, M.; Demyk, K.; Doi, Y.; Hughes, A.; Lefèvre, C.; Marshall, D. J.; Meny, C.; Montillaud, J.; Pagani, L.; Paradis, D.; Ristorcelli, I.; Malinen, J.; Montier, L. A.; Paladini, R.; Pelkonen, V.-M.; Rivera-Ingraham, A.

2015-12-01

Context. The Galactic Cold Cores project has carried out Herschel photometric observations of 116 fields where the Planck survey has found signs of cold dust emission. The fields contain sources in different environments and different phases of star formation. Previous studies have revealed variations in their dust submillimetre opacity. Aims: The aim is to measure the value of dust opacity spectral index and to understand its variations spatially and with respect to other parameters, such as temperature, column density, and Galactic location. Methods: The dust opacity spectral index β and the dust colour temperature T are derived using Herschel and Planck data. The relation between β and T is examined for the whole sample and inside individual fields. Results: Based on IRAS and Planck data, the fields are characterised by a median colour temperature of 16.1 K and a median opacity spectral index of β = 1.84. The values are not correlated with Galactic longitude. We observe a clear T-β anti-correlation. In Herschel observations, constrained at lower resolution by Planck data, the variations follow the column density structure and βFIR can rise to ~2.2 in individual clumps. The highest values are found in starless clumps. The Planck 217 GHz band shows a systematic excess that is not restricted to cold clumps and is thus consistent with a general flattening of the dust emission spectrum at millimetre wavelengths. When fitted separately below and above 700 μm, the median spectral index values are βFIR ~ 1.91 and β(mm) ~ 1.66. Conclusions: The spectral index changes as a function of column density and wavelength. The comparison of different data sets and the examination of possible error sources show that our results are robust. However, β variations are partly masked by temperature gradients and the changes in the intrinsic grain properties may be even greater. Planck http://www.esa.int/Planck is a project of the European Space Agency - ESA - with instruments provided by two scientific consortia funded by ESA member states (in particular the lead countries: France and Italy) with contributions from NASA (USA), and telescope reflectors provided in a collaboration between ESA and a scientific consortium led and funded by Denmark.Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.Table 3 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/584/A94Appendices are available in electronic form at http://www.aanda.org

The 2-79 keV X-ray Spectrum of the Circinus Galaxy with NuSTAR, XMM-Newton and Chandra: a Fully Compton-Thick Active Galactic Nucleus

DOE PAGES

Arevalo, P.; Bauer, F. E.; Puccetti, S.; ...

2014-07-30

Here, the Circinus galaxy is one of the closest obscured active galactic nuclei (AGNs), making it an ideal target for detailed study. Combining archival Chandra and XMM-Newton data with new NuSTAR observations, we model the 2-79 keV spectrum to constrain the primary AGN continuum and to derive physical parameters for the obscuring material. Chandra's high angular resolution allows a separation of nuclear and off-nuclear galactic emission. In the off-nuclear diffuse emission, we find signatures of strong cold reflection, including high equivalent-width neutral Fe lines. This Compton-scattered off-nuclear emission amounts to 18% of the nuclear flux in the Fe line region,more » but becomes comparable to the nuclear emission above 30 keV. The new analysis no longer supports a prominent transmitted AGN component in the observed band. We find that the nuclear spectrum is consistent with Compton scattering by an optically thick torus, where the intrinsic spectrum is a power law of photon index Γ = 2.2-2.4, the torus has an equatorial column density of N H = (6-10) × 10 24 cm –2, and the intrinsic AGN 2-10 keV luminosity is (2.3-5.1) × 10 42 erg s –1. These values place Circinus along the same relations as unobscured AGNs in accretion rate versus Γ and L X versus L IR phase space. NuSTAR's high sensitivity and low background allow us to study the short timescale variability of Circinus at X-ray energies above 10 keV for the first time. Here, the lack of detected variability favors a Compton-thick absorber, in line with the spectral fitting results.« less

Infrared Spectroscopy of HR 4796A's Bright Outer Cometary Ring + Tenuous Inner Hot Dust Cloud

NASA Astrophysics Data System (ADS)

Lisse, C. M.; Sitko, M. L.; Marengo, M.; Vervack, R. J., Jr.; Fernandez, Y. R.; Mittal, T.; Chen, C. H.

2017-11-01

We have obtained new NASA/IRTF SpeX spectra of the HR 4796A debris ring system. We find a unique red excess flux that extends out to ˜9 μm in Spitzer IRS spectra, where thermal emission from cold, ˜100 K dust from the system’s ring at ˜75 au takes over. Matching imaging ring photometry, we find the excess consists of NIR reflectance from the ring, which is as red as that of old, processed comet nuclei, plus a tenuous thermal emission component from close-in, T ˜ 850 K circumstellar material evincing an organic/silicate emission feature complex at 7-13 μm. Unusual, emission-like features due to atomic Si, S, Ca, and Sr were found at 0.96-1.07 μm, likely sourced by rocky dust evaporating in the 850 K component. An empirical cometary dust phase function can reproduce the scattered light excess and 1:5 balance of scattered versus thermal energy for the ring with optical depth < τ > ≥slant 0.10 in an 8 au wide belt of 4 au vertical height and M dust > 0.1-0.7 M Mars. Our results are consistent with HR 4796A, consisting of a narrow shepherded ring of devolatilized cometary material associated with multiple rocky planetesimal subcores and a small steady stream of dust inflowing from this belt to a rock sublimation zone at ˜1 au from the primary. These subcores were built from comets that have been actively emitting large, reddish dust for >0.4 Myr at ˜100 K, the temperature at which cometary activity onset is seen in our solar system.

Submesoscale CO2 variability across an upwelling front off Peru

NASA Astrophysics Data System (ADS)

Köhn, Eike E.; Thomsen, Sören; Arévalo-Martínez, Damian L.; Kanzow, Torsten

2017-12-01

As a major source for atmospheric CO2, the Peruvian upwelling region exhibits strong variability in surface fCO2 on short spatial and temporal scales. Understanding the physical processes driving the strong variability is of fundamental importance for constraining the effect of marine emissions from upwelling regions on the global CO2 budget. In this study, a frontal decay on length scales of 𝒪(10 km) was observed off the Peruvian coast following a pronounced decrease in down-frontal (equatorward) wind speed with a time lag of 9 h. Simultaneously, the sea-to-air flux of CO2 on the inshore (cold) side of the front dropped from up to 80 to 10 mmol m-2 day-1, while the offshore (warm) side of the front was constantly outgassing at a rate of 10-20 mmol m-2 day-1. Based on repeated ship transects the decay of the front was observed to occur in two phases. The first phase was characterized by a development of coherent surface temperature anomalies which gained in amplitude over 6-9 h. The second phase was characterized by a disappearance of the surface temperature front within 6 h. Submesoscale mixed-layer instabilities were present but seem too slow to completely remove the temperature gradient in this short time period. Dynamics such as a pressure-driven gravity current appear to be a likely mechanism behind the evolution of the front.

Virtual cathode emission of an annular cold cathode

NASA Astrophysics Data System (ADS)

Park, S.-d.; Kim, J.-h.; Han, J.; Yoon, M.; Park, S. Y.; Choi, D. W.; Shin, J. W.; So, J. H.

2009-11-01

Recent measurement of voltage V and current I of the electron gun of a relativistic klystron amplifier revealed that the resulting current-voltage relationship appeared to differ from the usual Child-Langmuir law (I∝V3/2) especially during the initial period of voltage increase. This paper attempts to explain this deviation by examining the emission mechanism using particle-in-cell simulation. The emission area in the cathode increased stepwise as the applied voltage increased and within each step the current and voltage followed the Child-Langmuir law. The electron emission began when the voltage reached a threshold, and the perveance increased with the emission area. Furthermore, an apparent virtual cathode was formed which was larger than the cathode tip. This occurs because, above a certain voltage, the emission from the edge and the side of the cathode surface dominates the emission from the front-end surface.

Experimental Demonstration of a Synthetic Lorentz Force by Using Radiation Pressure.

PubMed

Šantić, N; Dubček, T; Aumiler, D; Buljan, H; Ban, T

2015-09-02

Synthetic magnetism in cold atomic gases opened the doors to many exciting novel physical systems and phenomena. Ubiquitous are the methods used for the creation of synthetic magnetic fields. They include rapidly rotating Bose-Einstein condensates employing the analogy between the Coriolis and the Lorentz force, and laser-atom interactions employing the analogy between the Berry phase and the Aharonov-Bohm phase. Interestingly, radiation pressure - being one of the most common forces induced by light - has not yet been used for synthetic magnetism. We experimentally demonstrate a synthetic Lorentz force, based on the radiation pressure and the Doppler effect, by observing the centre-of-mass motion of a cold atomic cloud. The force is perpendicular to the velocity of the cold atomic cloud, and zero for the cloud at rest. Our novel concept is straightforward to implement in a large volume, for a broad range of velocities, and can be extended to different geometries.

Astrochemistry: Recent Advances in the Study of Carbon Molecules in Space

NASA Technical Reports Server (NTRS)

Salama, Farid

2006-01-01

Carbon molecules and ions play an important role in space. Polycyclic Aromatic Hydrocarbons (PAHs) are the best-known candidates to account for the infrared emission bands (UIR bands) and PAH spectral features are now being used as probes of the interstellar medium in Galactic and extra-galactic environments. PAHs are also thought to be among the carriers of the diffuse interstellar absorption bands (DIBs). In the model dealing with the interstellar spectral features, PAHs are present as a mixture of radicals, ions and neutral species. PAH ionization states reflect the ionization balance of the medium while PAH size, composition, and structure reflect the energetic and chemical history of the medium. A major challenge for laboratory Astrochemistry is to reproduce (in a realistic way) the physical conditions that exist in the emission and absorption interstellar zones. An extensive laboratory program has been developed in various laboratories to characterize the physical and chemical properties of PAHs in astrophysical environments and to describe how they influence the radiation and energy balance in space and the interstellar chemistry. In particular, laboratory experiments provide measurements of the spectral characteristics of interstellar PAH analogs from the ultraviolet and visible range to the infrared range for comparison with astronomical data. The harsh physical conditions of the interstellar medium - characterized by a low temperature, an absence of collisions and strong ultraviolet radiation fields - are simulated in the laboratory by associating a molecular beam with an ionizing discharge to generate a cold plasma expansion. PAH ions are formed from the neutral precursors in an isolated environment at low temperature (of the order of 100 K). The spectra of neutral and ionized PAHs are measured using the high sensitivity methods of cavity ring down spectroscopy (CRDS). These experiments provide unique information on the spectra of free, cold large carbon molecules and ions in the gas phase.

Revealing H I gas in emission and absorption on pc to kpc scales in a galaxy at z ˜ 0.017

NASA Astrophysics Data System (ADS)

Gupta, N.; Srianand, R.; Farnes, J. S.; Pidopryhora, Y.; Vivek, M.; Paragi, Z.; Noterdaeme, P.; Oosterloo, T.; Petitjean, P.

2018-05-01

We present a detailed study of the quasar-galaxy pair: J1243+4043-UGC 07904. The sight line of the background quasar ( zq = 1.5266) passes through a region of the galaxy (zg = 0.0169) at an impact parameter of 6.9 kpc with high metallicity (0.5 Z⊙) and negligible dust extinction. We detect H I 21-cm absorption from the foreground galaxy at arcsecond and milliarcsecond scales. For typical cold neutral medium (CNM) temperatures in the Milky Way, this 21-cm absorber can be classified as a damped Lyα absorber (DLA). We infer the harmonic mean spin temperature of the gas to be ˜400 K and for a simple two-phase medium we estimate the CNM fraction to be fCNM = 0.27. This is remarkably consistent with the CNM fraction observed in the Galaxy and less than that of high-redshift DLAs. The quasar exhibits a core-jet morphology on milliarcsecond scales, corresponding to an overall extent of ˜9 pc at zg. We show that the size of CNM absorbing clouds associated with the foreground galaxy is >5 pc and they may be part of cold gas structures that extend beyond ˜35 pc. Interestingly, the rotation measure of quasar J1243+4043 is higher than any other source in samples of quasars with high-z DLAs. However, we do not find any detectable differences in rotation measures and polarization fraction of sight lines with or without high-z (z ≥ 2) DLAs or low-z (z ≤ 0.3) 21-cm absorbers. Finally, the foreground galaxy UGC 07904 is also part of a galaxy group. We serendipitously detect H I 21-cm emission from four members of the group, and an ˜80 kpc long H I bridge connecting two of the other members. The latter, together with the properties of the group members, suggests that the group is a highly interactive environment.

Health effects of inhaled gasoline engine emissions.

PubMed

McDonald, Jacob D; Reed, Matthew D; Campen, Matthew J; Barrett, Edward G; Seagrave, JeanClare; Mauderly, Joe L

2007-01-01

Despite their prevalence in the environment, and the myriad studies that have shown associations between morbidity or mortality with proximity to roadways (proxy for motor vehicle exposures), relatively little is known about the toxicity of gasoline engine emissions (GEE). We review the studies conducted on GEE to date, and summarize the findings from each of these studies. While there have been several studies, most of the studies were conducted prior to 1980 and thus were not conducted with contemporary engines, fuels, and driving cycles. In addition, many of the biological assays conducted during those studies did not include many of the assays that are conducted on contemporary inhalation exposures to air pollutants, including cardiovascular responses and others. None of the exposures from these earlier studies were characterized at the level of detail that would be considered adequate today. A recent GEE study was conducted as part of the National Environmental Respiratory Center (www.nercenter.org). In this study several in-use mid-mileage General Motors (Chevrolet S-10) vehicles were purchased and utilized for inhalation exposures. An exposure protocol was developed where engines were operated with a repeating California Unified Driving Cycle with one cold start per day. Two separate engines were used to provide two cold starts over a 6-h inhalation period. The exposure atmospheres were characterized in detail, including detailed chemical and physical analysis of the gas, vapor, and particle phase. Multiple rodent biological models were studied, including general toxicity and inflammation (e.g., serum chemistry, lung lavage cell counts/differentials, cytokine/chemokine analysis, histopathology), asthma (adult and in utero exposures with pulmonary function and biochemical analysis), cardiovascular effects (biochemical and electrocardiograph changes in susceptible rodent models), and susceptibility to infection (Pseudomonas bacteria challenge). GEE resulted in significant biological effects for upregulation of MIP-2, clearance of Pseudomonas bacteria, development of allergic response after in utero exposure, and cardiovascular indicators of vasoconstriction, oxidant stress, and damage.

Climate and chemistry effects of a regional scale nuclear conflict

NASA Astrophysics Data System (ADS)

Stenke, A.; Hoyle, C. R.; Luo, B.; Rozanov, E.; Gröbner, J.; Maag, L.; Brönnimann, S.; Peter, T.

2013-10-01

Previous studies have highlighted the severity of detrimental effects for life on earth after an assumed regionally limited nuclear war. These effects are caused by climatic, chemical and radiative changes persisting for up to one decade. However, so far only a very limited number of climate model simulations have been performed, giving rise to the question how realistic previous computations have been. This study uses the coupled chemistry climate model (CCM) SOCOL, which belongs to a different family of CCMs than previously used, to investigate the consequences of such a hypothetical nuclear conflict. In accordance with previous studies, the present work assumes a scenario of a nuclear conflict between India and Pakistan, each applying 50 warheads with an individual blasting power of 15 kt ("Hiroshima size") against the major population centers, resulting in the emission of tiny soot particles, which are generated in the firestorms expected in the aftermath of the detonations. Substantial uncertainties related to the calculation of likely soot emissions, particularly concerning assumptions of target fuel loading and targeting of weapons, have been addressed by simulating several scenarios, with soot emissions ranging from 1 to 12 Tg. Their high absorptivity with respect to solar radiation leads to a rapid self-lofting of the soot particles into the strato- and mesosphere within a few days after emission, where they remain for several years. Consequently, the model suggests earth's surface temperatures to drop by several degrees Celsius due to the shielding of solar irradiance by the soot, indicating a major global cooling. In addition, there is a substantial reduction of precipitation lasting 5 to 10 yr after the conflict, depending on the magnitude of the initial soot release. Extreme cold spells associated with an increase in sea ice formation are found during Northern Hemisphere winter, which expose the continental land masses of North America and Eurasia to a cooling of several degrees. In the stratosphere, the strong heating leads to an acceleration of catalytic ozone loss and, consequently, to enhancements of UV radiation at the ground. In contrast to surface temperature and precipitation changes, which show a linear dependence to the soot burden, there is a saturation effect with respect to stratospheric ozone chemistry. Soot emissions of 5 Tg lead to an ozone column reduction of almost 50% in northern high latitudes, while emitting 12 Tg only increases ozone loss by a further 10%. In summary, this study, though using a different chemistry climate model, corroborates the previous investigations with respect to the atmospheric impacts. In addition to these persistent effects, the present study draws attention to episodically cold phases, which would likely add to the severity of human harm worldwide. The best insurance against such a catastrophic development would be the delegitimization of nuclear weapons.

Using Paraffin PCM, Cryogel and TEC to Maintain Comet Surface Sample Cold from Earth Approach Through Retrieval

NASA Technical Reports Server (NTRS)

Choi, Michael K.

2017-01-01

An innovative thermal design concept to maintain comet surface samples cold (for example, 263 degrees Kelvin, 243 degrees Kelvin or 223 degrees Kelvin) from Earth approach through retrieval is presented. It uses paraffin phase change material (PCM), Cryogel insulation and thermoelectric cooler (TEC), which are commercially available.

Evidence for a Multiphase ISM in Early Type Galaxies and Elliptical Galaxies with Strong Radio Continuum

NASA Technical Reports Server (NTRS)

Kim, Dong Woo

1997-01-01

We have observed NGC 1316 (Fornax A) with the ROSAT HRI. In this paper, we present the results of these observations and we complement them with the spectral analysis of the archival PSPC data. The spectral properties suggest the presence of a significant component of thermal X-ray emission (greater than 60%), amounting to approx. 10(exp 9) solar mass of hot ISM. Within 3 feet from the nucleus of NGC 1316, the HRI X-ray surface brightness falls as r(exp -2) following the stellar light. In the inner approx. 30 inch., however, the X-ray surface brightness is significantly elongated, contrary to the distribution of stellar light, which is significantly rounder within 10 inch. This again argues for a non-stellar origin of the X-ray emission. This flattened X-ray feature is suggestive of either the disk-like geometry of a rotating cooling flow and/or the presence of extended, elongated dark matter. By comparing the morphology of the X-ray emission with the distribution of optical dust patches, we find that the X-ray emission is significantly reduced at the locations where the dust patches are more pronounced, indicating that at least some of the X-ray photons are absorbed by the cold ISM. We also compare the distribution of the hot and cold ISM with that of the ionized gas, using recently obtained H(sub alpha) CCD data. We find that the ionized gas is distributed roughly along the dust patches and follows the large scale X-ray distribution at r greater than 1 foot from the nucleus. However, there is no one-to-one correspondence between ionized gas and hot gas. Both morphological relations and kinematics suggest different origins for hot and cold ISM. The radio jets in projection appear to pass perpendicularly through the central X-ray ellipsoid. Comparison of thermal and radio pressures suggests that the radio jets are confined by the surrounding hot gaseous medium.

Starch-related alpha-glucan/water dikinase is involved in the cold-induced development of freezing tolerance in Arabidopsis.

PubMed

Yano, Ryoichi; Nakamura, Masanobu; Yoneyama, Tadakatsu; Nishida, Ikuo

2005-06-01

Cold-induced soluble sugar accumulation enhances the degree of freezing tolerance in various cold-hardy plants including Arabidopsis (Arabidopsis thaliana), where soluble sugars accumulate in only a few hours at 2 degrees C. Hence, along with photosynthesis, starch degradation might play a significant role in cold-induced sugar accumulation and enhanced freezing tolerance. Starch-related alpha-glucan/water dikinase (EC 2.7.9.4), encoded by Arabidopsis STARCH EXCESS 1 (SEX1), is hypothesized to regulate starch degradation in plastids by phosphorylating starch, thereby ensuring better accessibility by starch-degrading enzymes. Here, we show that Arabidopsis sex1 mutants, when incubated at 2 degrees C for 1 d, were unable to accumulate maltooligosaccharides or normal glucose and fructose levels. In addition, they displayed impaired freezing tolerance. After 7 d at 2 degrees C, sex1 mutants did not show any of the above abnormal phenotypes but displayed slightly higher leaf starch contents. The impaired freezing tolerance of sex1 mutants was restored by overexpression of wild-type SEX1 cDNA using the cauliflower mosaic virus 35S promoter. The results demonstrate a genetic link between the SEX1 locus and plant freezing tolerance, and show that starch degradation is important for enhanced freezing tolerance during an early phase of cold acclimation. However, induction of starch degradation was not accompanied by significant changes in alpha-glucan/water dikinase activity in leaf extracts and preceded cold-induced augmentation of SEX1 transcripts. Therefore, we conclude that augmentation of SEX1 transcripts might be a homeostatic response to low temperature, and that starch degradation during an early phase of cold acclimation could be regulated by a component(s) of a starch degradation pathway(s) downstream of SEX1.

Acclimation to cold and warm temperatures is associated with differential expression of male carp blood proteins involved in acute phase and stress responses, and lipid metabolism.

PubMed

Dietrich, Mariola A; Hliwa, Piotr; Adamek, Mikołaj; Steinhagen, Dieter; Karol, Halina; Ciereszko, Andrzej

2018-05-01

The environmental temperature affects plasma biochemical indicators, antioxidant status and hematological and immunological parameters in fish. So far, only single blood proteins have been identified in response to temperature changes. The aim of this study was to compare the proteome of carp blood plasma from males acclimated to warm (30 °C) and cold (10 °C) temperatures by two-dimensional differential gel electrophoresis followed by MALDI-TOF/TOF mass spectrometry. A total of 47 spots were found to be differentially regulated by temperature (>1.2-fold change, p < 0.05): 25 protein spots were more abundant in warm-acclimated males and 22 were enriched in cold-acclimated males. The majority of differentially regulated proteins were associated with acute phase response signalling involved in: i) activation of the complement system (complement C3-H1), ii) neutralization of proteolytic enzymes (inter-alpha inhibitor H3, fetuin, serpinA1, antithrombin, alpha2-macroglobulin), iii) scavenging of free hemoglobin and radicals (haptoglobin, Wap65 kDa), iv) clot-formation (fibrinogen beta and alpha chain, T-kininogen) and v) the host's immune response modulation (ApoA1 and ApoA2). However, quite different sets of these proteins or proteoforms were involved in response to cold and warm temperatures. In addition, cold acclimation seems to be related to the proteins involved in lipid metabolism (apolipoproteins A and 14 kDa) and stress response (corticosteroid binding globulin). We discovered a strongly regulated protein Cap31 upon cold acclimation, which can serve as a potential blood biomarker of cold response in carp. These studies significantly extend our knowledge concerning mechanisms underlying thermal adaptation in poikilotherms. Copyright © 2018. Published by Elsevier Ltd.

Cold fission description with constant and varying mass asymmetries

NASA Astrophysics Data System (ADS)

Duarte, S. B.; Rodríguez, O.; Tavares, O. A. P.; Gonçalves, M.; García, F.; Guzmán, F.

1998-05-01

Different descriptions for varying the mass asymmetry in the fragmentation process are used to calculate the cold fission barrier penetrability. The relevance of the appropriate choice for both the description of the prescission phase and inertia coefficient to unify alpha decay, cluster radioactivity, and spontaneous cold fission processes in the same theoretical framework is explicitly shown. We calculate the half-life of all possible partition modes of nuclei of A>200 following the most recent Mass Table by Audi and Wapstra. It is shown that if one uses the description in which the mass asymmetry is maintained constant during the fragmentation process, the experimental half-life values and mass yield of 234U cold fission are satisfactorily reproduced.

Cloud-Resolving Model Simulations of Aerosol-Cloud Interactions Triggered by Strong Aerosol Emissions in the Arctic

NASA Astrophysics Data System (ADS)

Wang, H.; Kravitz, B.; Rasch, P. J.; Morrison, H.; Solomon, A.

2014-12-01

Previous process-oriented modeling studies have highlighted the dependence of effectiveness of cloud brightening by aerosols on cloud regimes in warm marine boundary layer. Cloud microphysical processes in clouds that contain ice, and hence the mechanisms that drive aerosol-cloud interactions, are more complicated than in warm clouds. Interactions between ice particles and liquid drops add additional levels of complexity to aerosol effects. A cloud-resolving model is used to study aerosol-cloud interactions in the Arctic triggered by strong aerosol emissions, through either geoengineering injection or concentrated sources such as shipping and fires. An updated cloud microphysical scheme with prognostic aerosol and cloud particle numbers is employed. Model simulations are performed in pure super-cooled liquid and mixed-phase clouds, separately, with or without an injection of aerosols into either a clean or a more polluted Arctic boundary layer. Vertical mixing and cloud scavenging of particles injected from the surface is still quite efficient in the less turbulent cold environment. Overall, the injection of aerosols into the Arctic boundary layer can delay the collapse of the boundary layer and increase low-cloud albedo. The pure liquid clouds are more susceptible to the increase in aerosol number concentration than the mixed-phase clouds. Rain production processes are more effectively suppressed by aerosol injection, whereas ice precipitation (snow) is affected less; thus the effectiveness of brightening mixed-phase clouds is lower than for liquid-only clouds. Aerosol injection into a clean boundary layer results in a greater cloud albedo increase than injection into a polluted one, consistent with current knowledge about aerosol-cloud interactions. Unlike previous studies investigating warm clouds, the impact of dynamical feedback due to precipitation changes is small. According to these results, which are dependent upon the representation of ice nucleation processes in the employed microphysical scheme, Arctic geoengineering/shipping could have substantial local radiative effects, but is unlikely to be effective as the sole means of counterbalancing warming due to climate change.

Demonstration of a Single-Crystal Reflector-Filter for Enhancing Slow Neutron Beams

DOE PAGES

Muhrer, Guenter; Schönfeldt, Troels; Iverson, Erik B.; ...

2016-06-14

The cold polycrystalline beryllium reflector-filter concept has been used to enhance the cold neutron emission of cryogenic hydrogen moderators, while suppressing the intermediate wavelength and fast neutron emission at the same time. While suppressing the fast neutron emission is often desired, the suppression of intermediate wavelength neutrons is often unwelcome. It has been hypothesized that replacing the polycrystalline reflector-filter concept with a single-crystal reflector-filter concept would overcome the suppression of intermediate wavelength neutrons and thereby extend the usability of the reflector-filter concept to shorter but still important wavelengths. In this paper we present the first experimental data on a single-crystalmore » reflector-filter and compare experimental results with hypothesized performance. We find that a single-crystal reflector-filter retains the long-wavelength benefit of the polycrystalline reflector-filter, without suffering the same loss of important intermediate wavelength neutrons. Ultimately, this finding extends the applicability of the reflector-filter concept to intermediate wavelengths, and furthermore indicates that the reflector-filter benefits arise from its interaction with fast (background) neutrons, not with intermediate wavelength neutrons of potential interest in many types of neutron scattering.« less

The State of the Warm and Cold Gas in the Extreme Starburst at the Core of the Phoenix Galaxy Cluster (SPT-CLJ2344-4243)

NASA Astrophysics Data System (ADS)

McDonald, Michael; Swinbank, Mark; Edge, Alastair C.; Wilner, David J.; Veilleux, Sylvain; Benson, Bradford A.; Hogan, Michael T.; Marrone, Daniel P.; McNamara, Brian R.; Wei, Lisa H.; Bayliss, Matthew B.; Bautz, Marshall W.

2014-03-01

We present new optical integral field spectroscopy (Gemini South) and submillimeter spectroscopy (Submillimeter Array) of the central galaxy in the Phoenix cluster (SPT-CLJ2344-4243). This cluster was previously reported to have a massive starburst (~800 M ⊙ yr-1) in the central, brightest cluster galaxy, most likely fueled by the rapidly cooling intracluster medium. These new data reveal a complex emission-line nebula, extending for >30 kpc from the central galaxy, detected at [O II]λλ3726, 3729, [O III]λλ4959, 5007, Hβ, Hγ, Hδ, [Ne III]λ3869, and He II λ4686. The total Hα luminosity, assuming Hα/Hβ = 2.85, is L Hα = 7.6 ± 0.4 ×1043 erg s-1, making this the most luminous emission-line nebula detected in the center of a cool core cluster. Overall, the relative fluxes of the low-ionization lines (e.g., [O II], Hβ) to the UV continuum are consistent with photoionization by young stars. In both the center of the galaxy and in a newly discovered highly ionized plume to the north of the galaxy, the ionization ratios are consistent with both shocks and active galactic nucleus (AGN) photoionization. We speculate that this extended plume may be a galactic wind, driven and partially photoionized by both the starburst and central AGN. Throughout the cluster we measure elevated high-ionization line ratios (e.g., He II/Hβ, [O III]/Hβ), coupled with an overall high-velocity width (FWHM gsim 500 km s-1), suggesting that shocks are likely important throughout the interstellar medium of the central galaxy. These shocks are most likely driven by a combination of stellar winds from massive young stars, core-collapse supernovae, and the central AGN. In addition to the warm, ionized gas, we detect a substantial amount of cold, molecular gas via the CO(3-2) transition, coincident in position with the galaxy center. We infer a molecular gas mass of M_{H_2} = 2.2 ± 0.6 × 1010 M ⊙, which implies that the starburst will consume its fuel in ~30 Myr if it is not replenished. The L IR/M_{H_2} that we measure for this cluster is consistent with the starburst limit of 500 L ⊙/M ⊙, above which radiation pressure is able to disperse the cold reservoir. The combination of the high level of turbulence in the warm phase and the high L IR/M_{H_2} ratio suggests that this violent starburst may be in the process of quenching itself. We propose that phases of rapid star formation may be common in the cores of galaxy clusters, but so short-lived that their signatures are quickly erased and appear only in a subsample of the most strongly cooling clusters.

Effect of Cold Deformation and Annealing on the Microstructure and Tensile Properties of a HfNbTaTiZr Refractory High Entropy Alloy

NASA Astrophysics Data System (ADS)

Senkov, O. N.; Pilchak, A. L.; Semiatin, S. L.

2018-07-01

The microstructure and tensile properties of HfNbTaTiZr after cold working and annealing were investigated. Cold work was introduced by axial compression followed by rolling resulting in a total thickness reduction of 89 pct without any evidence of cracking. The cold-worked material retained a single-phase microstructure and had a room temperature tensile yield stress σ 0.2 = 1438 MPa, peak true stress σ p = 1495 MPa, and true fracture strain ɛ f = 5 pct. Annealing at 800 °C for up to 256 hours resulted in the precipitation of Nb and Ta rich particles with a BCC crystal structure inside a Hf-and-Zr-enriched BCC matrix. The second phase particles nucleated heterogeneously inside deformation bands and slip lines and coarsened during annealing. Analysis of the coarsening behavior suggested that kinetics were controlled by the diffusion of Nb and Ta. In the two-phase material, σ 0.2 and σ p decreased from 1159 to 1071 MPa and from 1174 to 1074 MPa, respectively, with an increase in particle diameter from 0.18 to 0.72 μm, while ɛ f remained between 5 and 8 pct. Full recrystallization and normal grain growth, with the activation energy of 238 kJ/mol and activation volume of 5.3 to 9.6 m3/mol, occurred during annealing above 1000 °C. After heat treatment at this temperature, the alloy was characterized by a single-phase BCC structure with σ 0.2 = 1110 to 1115 MPa, σ p = 1160 to 1195 MPa, and ɛ f = 12 to 19 pct with the maximum values attained after annealing for 1 hour.

Effect of Cold Deformation and Annealing on the Microstructure and Tensile Properties of a HfNbTaTiZr Refractory High Entropy Alloy

NASA Astrophysics Data System (ADS)

Senkov, O. N.; Pilchak, A. L.; Semiatin, S. L.

2018-05-01

The microstructure and tensile properties of HfNbTaTiZr after cold working and annealing were investigated. Cold work was introduced by axial compression followed by rolling resulting in a total thickness reduction of 89 pct without any evidence of cracking. The cold-worked material retained a single-phase microstructure and had a room temperature tensile yield stress σ 0.2 = 1438 MPa, peak true stress σ p = 1495 MPa, and true fracture strain ɛ f = 5 pct. Annealing at 800 °C for up to 256 hours resulted in the precipitation of Nb and Ta rich particles with a BCC crystal structure inside a Hf-and-Zr-enriched BCC matrix. The second phase particles nucleated heterogeneously inside deformation bands and slip lines and coarsened during annealing. Analysis of the coarsening behavior suggested that kinetics were controlled by the diffusion of Nb and Ta. In the two-phase material, σ 0.2 and σ p decreased from 1159 to 1071 MPa and from 1174 to 1074 MPa, respectively, with an increase in particle diameter from 0.18 to 0.72 μm, while ɛ f remained between 5 and 8 pct. Full recrystallization and normal grain growth, with the activation energy of 238 kJ/mol and activation volume of 5.3 to 9.6 m3/mol, occurred during annealing above 1000 °C. After heat treatment at this temperature, the alloy was characterized by a single-phase BCC structure with σ 0.2 = 1110 to 1115 MPa, σ p = 1160 to 1195 MPa, and ɛ f = 12 to 19 pct with the maximum values attained after annealing for 1 hour.

[Efficacy of nebulizer therapy with acetylcystein in outpatients with chronic obstructive lung disease].

PubMed

Stepanishcheva, L A; Ignatova, G L; Blinova, E V

2005-01-01

Chronic obstructive lung disease (COLD) is a widespread illness with constantly growing mortality. Mucolytic therapy plays a significant role in treatment of patients with COLD. The paper contains the results of nebulization with acetyl-cystein as part of rehabilitation program in outpatients with stable clinical course of I-II stage of COLD. The results demonstrated significant clinical improvement, as well as positive changes in external respiration parameters (1 sforced expiratory volume), increase of physical activity tolerance, and disappearance of acute inflammation phase reactants in saliva.

[How can we improve symptomatic hypotension in hemodialysis patients: cold dialysis vs isothermic dialysis].

PubMed

Ramos, R; Soto, C; Mestres, R; Jara, J; Zequera, H; Merello, J I; Moreso, F

2007-01-01

Symptomatic hypotension is the most frequent acute complication affecting patients during chronic hemodialysis treatment sessions. Many reports have demonstrated that the use of cool dialysate has a protective effect on blood pressure during hemodialysis treatments. In the present study, we investigated whether preventing the hyperthermic response had favourable effects on hemodynamic stability during the hemodialysis procedure while affording good tolerance to patients. We investigated the effect of thermal control of dialysate on hemodynamic stability in hypotension-prone patients in our center. Patients were eligible for the study if they had symptomatic hypotensive episodes (> 3/12session/ month) during the screening phase. The study was designed with two phases for the same selected patients and two treatment arms, each phase lasting 4 weeks. In the first phase, we adjusted dialysate temperature on 36 masculineC for 12 sessions (cold dialysis) and in the second phase we used a device allowing the regulation of thermal balance (Blood Temperature Monitor; Fresenius Medical Care, Bad Homberg, Germany), that keep body temperature unchanged (isothermic dialysis). Nine HD patients were enrolled and completed the study. During the screening phase the mean ultrafiltration was 4 1% of dry weight, and blood pressure decreased from 9916 to 8016 mm Hg (p<0.001). In 5.01.7 sessions of 12 treatments were complicated by hypotension. In the first and second phase we observed a decrease of complicated treatments with symptomatic hypotension (5.01.7 versus 2.71.6 y 2.81.7; p<0.01). Both procedures: Cold dialysis and Isothermic dialysis was well tolerated by patients. Results show that active control of body temperature can significantly improve intradialytic tolerance in hypotension-prone patients.

Spatiotemporal variability of extreme temperature frequency and amplitude in China

NASA Astrophysics Data System (ADS)

Zhang, Yuanjie; Gao, Zhiqiu; Pan, Zaitao; Li, Dan; Huang, Xinhui

2017-03-01

Temperature extremes in China are examined based on daily maximum and minimum temperatures from station observations and multiple global climate models. The magnitude and frequency of extremes are expressed in terms of return values and periods, respectively, estimated by the fitted Generalized Extreme Value (GEV) distribution of annual extreme temperatures. The observations suggest that changes in temperature extremes considerably exceed changes in the respective climatological means during the past five decades, with greater amplitude of increases in cold extremes than in warm extremes. The frequency of warm (cold) extremes increases (decreases) over most areas, with an increasingly faster rate as the extremity level rises. Changes in warm extremes are more dependent on the varying shape of GEV distribution than the location shift, whereas changes in cold extremes are more closely associated with the location shift. The models simulate the overall pattern of temperature extremes during 1961-1981 reasonably well in China, but they show a smaller asymmetry between changes in warm and cold extremes primarily due to their underestimation of increases in cold extremes especially over southern China. Projections from a high emission scenario show the multi-model median change in warm and cold extremes by 2040 relative to 1971 will be 2.6 °C and 2.8 °C, respectively, with the strongest changes in cold extremes shifting southward. By 2040, warm extremes at the 1971 20-year return values would occur about every three years, while the 1971 cold extremes would occur once in > 500 years.

Volatile organic compound constituents from an integrated iron and steel facility.

PubMed

Tsai, Jiun-Horng; Lin, Kuo-Hsiung; Chen, Chih-Yu; Lai, Nina; Ma, Sen-Yi; Chiang, Hung-Lung

2008-09-15

This study measured the volatile organic compound (VOC) constituents of four processes in an integrated iron and steel industry; cokemaking, sintering, hot forming, and cold forming. Toluene, 1,2,4-trimethylbenzene, isopentane, m,p-xylene, 1-butene, ethylbenzene, and benzene were the predominant VOC species in these processes. However, some of the chlorinated compounds were high (hundreds ppbv), i.e., trichloroethylene in all four processes, carbon tetrachloride in the hot forming process, chlorobenzene in the cold forming process, and bromomethane in the sintering process. In the sintering process, the emission factors of toluene, benzene, xylene, isopentane, 1,2,4-trimethylbenzene, and ethylbenzene were over 9 g/tonne-product. In the vicinity of the manufacturing plant, toluene, isopentane, 1,2,4-trimethylbenzene, xylene and ethylbenzene were high. Toluene, 1,2,4-trimethylbenzene, xylene, 1-butene and isopentane were the major ozone formation species. Aromatic compounds were the predominant VOC groups, constituting 45-70% of the VOC concentration and contributing >70% to the high ozone formation potential in the stack exhaust and workplace air. The sequence of VOC concentration and ozone formation potential was as follows: cold forming>sintering>hot forming>cokemaking. For the workplace air, cokemaking was the highest producer, which was attributed to the fugitive emissions of the coke oven and working process release.

Molecular Line Emission as a Tool for Galaxy Observations (LEGO). I. HCN as a tracer of moderate gas densities in molecular clouds and galaxies

NASA Astrophysics Data System (ADS)

Kauffmann, Jens; Goldsmith, Paul F.; Melnick, Gary; Tolls, Volker; Guzman, Andres; Menten, Karl M.

2017-09-01

Trends observed in galaxies, such as the Gao & Solomon relation, suggest a linear relationship between the star formation rate and the mass of dense gas available for star formation. Validation of such trends requires the establishment of reliable methods to trace the dense gas in galaxies. One frequent assumption is that the HCN (J = 1-0) transition is unambiguously associated with gas at H2 densities ≫ 104 cm-3. If so, the mass of gas at densities ≫ 104 cm-3 could be inferred from the luminosity of this emission line, LHCN (1-0). Here we use observations of the Orion A molecular cloud to show that the HCN (J = 1-0) line traces much lower densities 103 cm-3 in cold sections of this molecular cloud, corresponding to visual extinctions AV ≈ 6 mag. We also find that cold and dense gas in a cloud like Orion produces too little HCN emission to explain LHCN (1-0) in star forming galaxies, suggesting that galaxies might contain a hitherto unknown source of HCN emission. In our sample of molecules observed at frequencies near 100 GHz (also including 12CO, 13CO, C18O, CN, and CCH), N2H+ is the only species clearly associated with relatively dense gas.

Controlled rolling process for dual phase steels and application to rod, wire, sheet and other shapes

DOEpatents

Thomas, G.; Ahn, J.H.; Kim, N.J.

1986-10-28

An improved, energy efficient, hot rolling method for direct production of cold formable dual-phase steel is provided. The steel is heated to completely austenitize it and then continuously hot rolled and cooled down into the ferrite-austenite two phase region to a temperature which is just below the effective Ar[sub 3] temperature. The hot rolled steel is then rapidly quenched to provide an alloy containing strong, tough lath martensite (fibers) in a ductile soft ferrite matrix. The method is particularly useful for providing rods in which form the alloy is capable of being drawn into high strength wire or the like in a cold drawing operation without any intermediate annealing or patenting, and has excellent strength, ductility and fatigue characteristics. 3 figs.

Controlled rolling process for dual phase steels and application to rod, wire, sheet and other shapes

DOEpatents

Thomas, Gareth; Ahn, Jae-Hwan; Kim, Nack-Joon

1986-01-01

An improved, energy efficient, hot rolling method for direct production of cold formable dual-phase steel is provided. The steel is heated to completely austenitize it and then continuously hot rolled and cooled down into the ferrite-austenite two phase region to a temperature which is just below the effective Ar.sub.3 temperature. The hot rolled steel is then rapidly quenched to provide an alloy containing strong, tough lath martensite (fibers) in a ductile soft ferrite matrix. The method is particularly useful for providing rods in which form the alloy is capable of being drawn into high strength wire or the like in a cold drawing operation without any intermediate annealing or patenting, and has excellent strength, ductility and fatigue characteristics.

Investigation of crystalline morphology in poly (ether ether ketone) using dielectric relaxation spectroscopy

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

Kalika, D.S.; Krishnaswamy, R.K.

1993-12-31

The relaxation behavior of poly (ether ether ketone) [PEEK] has been investigated using dielectric relaxation spectroscopy; the glass-rubber ({alpha}) relaxation and a sub-glass ({beta}) relaxation were examined for the amorphous material and both cold-crystallized and melt-crystallized specimens. Analysis of the data using the Cole-Cole modification of the Debye equation allowed determination of the dielectric relaxation strength and relaxation broadening parameter for both transitions as a function of material crystallization history. The crystallized specimens displayed a positive offset in isochronal loss temperature for both the {alpha} and {beta} relaxations, with the {alpha} relaxation broadened significantly. The measured dipolar response was interpretedmore » using a three-phase morphological model encompassing a crystalline phase, a mobile amorphous phase, and a rigid amorphous phase. Determination of phase fractions based on dipolar mobilization across the glass-rubber relaxation revealed a finite rigid amorphous phase fraction for both the cold-crystallized specimens which was relatively insensitive to thermal history and degree of crystallinity (W{sub RAP}40.20).« less

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

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.

High-efficiency Resonant rf Spin Rotator with Broad Phase Space Acceptance for Pulsed Polarized Cold Neutron Beams

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

Seo, P. -N.; Barron-Palos, L.; Bowman, J. D.

2008-01-01

High precision fundamental neutron physics experiments have been proposed for the intense pulsed spallation neutron beams at JSNS, LANSCE, and SNS to test the standard model and search for new physics. Certain systematic effects in some of these experiments have to be controlled at the few ppb level. The NPD Gamma experiment, a search for the small parity-violating {gamma}-ray asymmetry A{sub Y} in polarized cold neutron capture on parahydrogen, is one example. For the NPD Gamma experiment we developed a radio-frequency resonant spin rotator to reverse the neutron polarization in a 9.5 cm x 9.5 cm pulsed cold neutron beammore » with high efficiency over a broad cold neutron energy range. The effect of the spin reversal by the rotator on the neutron beam phase space is compared qualitatively to rf neutron spin flippers based on adiabatic fast passage. We discuss the design of the spin rotator and describe two types of transmission-based neutron spin-flip efficiency measurements where the neutron beam was both polarized and analyzed by optically polarized {sup 3}He neutron spin filters. The efficiency of the spin rotator was measured at LANSCE to be 98.8 {+-} 0.5% for neutron energies from 3 to 20 meV over the full phase space of the beam. Systematic effects that the rf spin rotator introduces to the NPD Gamma experiment are considered.« less

Image-guided plasma therapy of cutaneous wound

NASA Astrophysics Data System (ADS)

Zhang, Zhiwu; Ren, Wenqi; Yu, Zelin; Zhang, Shiwu; Yue, Ting; Xu, Ronald

2014-02-01

The wound healing process involves the reparative phases of inflammation, proliferation, and remodeling. Interrupting any of these phases may result in chronically unhealed wounds, amputation, or even patient death. Despite the clinical significance in chronic wound management, no effective methods have been developed for quantitative image-guided treatment. We integrated a multimodal imaging system with a cold atmospheric plasma probe for image-guided treatment of chronic wound. Multimodal imaging system offers a non-invasive, painless, simultaneous and quantitative assessment of cutaneous wound healing. Cold atmospheric plasma accelerates the wound healing process through many mechanisms including decontamination, coagulation and stimulation of the wound healing. The therapeutic effect of cold atmospheric plasma is studied in vivo under the guidance of a multimodal imaging system. Cutaneous wounds are created on the dorsal skin of the nude mice. During the healing process, the sample wound is treated by cold atmospheric plasma at different controlled dosage, while the control wound is healed naturally. The multimodal imaging system integrating a multispectral imaging module and a laser speckle imaging module is used to collect the information of cutaneous tissue oxygenation (i.e. oxygen saturation, StO2) and blood perfusion simultaneously to assess and guide the plasma therapy. Our preliminary tests show that cold atmospheric plasma in combination with multimodal imaging guidance has the potential to facilitate the healing of chronic wounds.

Possible mechanisms for four regimes associated with cold events over East Asia

NASA Astrophysics Data System (ADS)

Yang, Zifan; Huang, Wenyu; Wang, Bin; Chen, Ruyan; Wright, Jonathon S.; Ma, Wenqian

2017-09-01

Circulation patterns associated with cold events over East Asia during the winter months of 1948-2014 are classified into four regimes by applying a k-means clustering method based on the area-weighted pattern correlation. The earliest precursor signals for two regimes are anticyclonic anomalies, which evolve into Ural and central Siberian blocking-like circulation patterns. The earliest precursor signals for the other two regimes are cyclonic anomalies, both of which evolve to amplify the East Asian trough (EAT). Both the blocking-like circulation patterns and amplified EAT favor the initialization of cold events. On average, the blocking-related regimes tend to last longer. The lead time of the earliest precursor signal for the central Siberian blocking-related regime is only 4 days, while those for the other regimes range from 16 to 18 days. The North Atlantic Oscillation plays essential roles both in triggering the precursor for the Ural blocking-related regime and in amplifying the precursors for all regimes. All regimes preferentially occur during the positive phase of the Eurasian teleconnection pattern and the negative phase of the El Niño-Southern Oscillation. For three regimes, surface cooling is primarily due to reduced downward infrared radiation and enhanced cold advection. For the remaining regime, which is associated with the southernmost cooling center, sensible and latent heat release and horizontal cold advection dominate the East Asian cooling.